Eshan Senanayake- Thesis 2011

1 Eshan Senanayake/ 201101042331

Design and Research on the Emergency

Braking System of Mining Monorail

Locomotives

Shandong University of Science & technology

(Supervisor; Mr. Zhu Xu Li)

Eshan Senanayake

2011 Mechatronics

201101042331


Design and Research on the Emergency Braking System of

Mining Monorail Locomotives

Abstract___________________________________________________

A monorail locomotive is a railway in which the track consists of a single rail, typically

elevated. The term is also used to describe the beam of the system, or the vehicles traveling on

such a beam or track. The term originates from joining mono (one) and rail (rail), from as early

as 1897, possibly from German engineer EugenLangen, who called an elevated railway system

with wagons suspended the EugenLangen One-railed Suspension Tramway

(EinschienigesHängebahnsystemEugenLangen).

The product quality of China’s coal auxiliary transport industry is still far behind the

developed countries in the world as design, manufacturing processes, and many other reasons,

and Moreover, as the majority of manufacturers in order to maintain technological superiority,

the core technology secret, it cause domestic manufacturers must rely on foreign technology,

photographs health production, can’t solve the problem of product design and manufacturing,

and could hardly help the manufacturers product new products.

In this paper, Monorail brake system design and Performance analysis methods was

researched, it can be used to reduce costs, improve product quality, and to design a more secure

and reliable braking system. In this paper, several commonly used mechanism of monorail

brake system was analyzed, it was based on the actual research on the monorail equipment and

refer to relevant information. Then summarize the advantages and disadvantages of various

brake mechanism.

On that basis, a set of reasonable structure was offered and the main dimensions was

determined; the brake lining material was studied and determine to use copper-tin alloy as a

brake material; the springs, hydraulic cylinders and other key components type-selection

design was mentioned. Hydraulic brake system model was established by the MSC-EASY5

software in this paper. And then make a simulation analysis about the hydraulic brake circuit

simulate the unloading time of the brake cylinder in the spring force, in order to verify whether

the response time of the braking system to meet the requirements of the coal safety regulations.

Through the PRO/E software to establish a three-dimensional solid model, and then

imported into the ADAMS by the MECHANISM/Pro software, using the ADAMS software to

make the kinematic and dynamic Science simulation. Verify the simulation accuracy during

braking action, while, through the force measuring device simulation, obtained the static state

of the braking force value in computer simulation. The results show that the results of

simulation and calculation results are consistent,achieve the design requirements.

Key words: Emergency brake, Hydraulic control, friction materials, centrifugal releaser, CAD,

virtual prototyping technology, ANSYS.


Contents___________________________________________________

1 Introduction

1.1 Research Background

1.2 Current Research Situation about the Braking System

1.3 Main Research Contents and Research Significance

2 Overall Design of the Monorail Emergency Braking System

2.1 Elementary Theory and Design Requirements of the Monorail Braking System

2.2 Selection of Brake Actuator

2.3 Selection of Speed Detection Mechanism

2.4 Selection of Friction Material

2.5 Summary

3 The Major Parts Design of the Monorail Emergency Braking System

3.1 Determination of Braking Force

3.2 The Selection of the Brake Spring

3.3 Design of Brake Hydraulic Cylinder

3.4 The Selection and Design of Other Important Parts

3.5 Summary

4 3D Solid Modeling and Simulation

4.13D Solid Modeling

4.2 Simulation of Braking Performance

4.3 Summary

5 Conclusions and Prospects

5.1Conclusions

5.2Prospects

References

Acknowledgement


1 Introduction______________________________________________

Nowadays, in the developed countries is very widely used suspended monorail transport.

With his help solve the problems above-ground isolation of traffic. Foreign and domestic

experience has shown successful results in the application of monorail transport not only as

overhead, but also as an underground. When operating in the mine of monorail transport

problems are resolved or simplified to transport people and support materials to develop. A

particular advantage is the practicality of use and safety.

There are two monorail system: the cable car and locomotive traction. Of these,

preference should be given to the second as it provides a very high safety. Also, when using

roads with cable traction problems arise opportunities to work on branched lines and

long-haul transport.

Early years-The first monorail prototype was made in Russia in 1820 by Ivan Elmanov.

Attempts at creating monorail alternatives to conventional railway shave been made since the

early part of the 19th century. The earliest patent was taken out by Henry Palmer in the UK in

1821, and the design was employed at Deptford Dockyard in South-East London, and a short

line for moving stone from a quarry near Cheshunt ,Hertfordshire to the River Lea, the

world's first monorail to carry passengers and the first railway in Hertfordshire.

Around 1879 a "one-rail" system was proposed independently by Haddon and by

Stringfellow, which used an inverted "/\" rail. It was intended for military use, but was also

seen to have civilian use as a "cheap railway."

Recent history-From the 1980s, with the rise of traffic congestion and urbanization,

monorails have experienced a resurgence in interest for mass transit usage, notable from the

early use by Japan. Tokyo Monorail, one of the world's busiest, averages 127,000 passengers

per day and has served over 1.5 billion passengers since 1964. Monorails have seen

continuing use in niche shuttle markets and amusement parks.

Modern mass transit monorail systems use developments of the ALWEG beam and tyre

approach, with only two suspended types in large use. Monorail configurations have also been

adopted by maglev trains. Chongqing Rail Transit in China has adopted a unique

ALWEG-based design with rolling stock is much wider than most monorails, with capacity

comparable to heavy rail. This is because Chongqing is criss-crossed by numerous hills,

mountains and rivers, therefore tunneling is not feasible except in some cases (Line 1 and

future Line 6) due to the extreme depth involved. India is developing monorails in several

cities for mass rapid transit with Mumbai Monorail being the first one.

In December 2014, the government of Malta proposed a monorail system to the

European Commission as an infrastructural project to benefit from EU funding. The network

would be 76 km (47 mi) long, which would make it the longest monorail network in the

world.

1.1 Research Background_____________________________________

In addition to the sum of coal mine auxiliary transportation of various transport refers to

transport coal production, including transportation of various materials, work equipment,

waste rock and associated personnel. Mine auxiliary transportation is an important part of the


production, according to statistics, labor accounts for more than half of the total labor

auxiliary transportation volume. In recent years, along with the ability to continuously

improve the domestic coal mining, and production of materials needed to increase, increase

the weight of the device, which auxiliary transport system efficiency, security put forward

higher requirements.

In 2012, the domestic coal industry a huge market demand and supply shocks, generally

speaking, it has gone through three stages. 1-4 months, supply and demand level is very, coal

prices stabilize; 5-9 months, significantly lower than the coal supply of coal demand, coal

prices have fallen, the cumulative increase in inventories; since October, coal prices remain

low and stable, the demand increase. At present, the pace of modernization of China to

accelerate the construction of the mine, more than 1.2 million tons of mine has 850 spots, its

coal production accounts for about 65% of the country, small mines (with an annual output of

300,000 tons) of production fell to 17% or less. Faced with rising coal stocks, prices, intense

competition phenomenon, various types of mines pay more attention to the problem of

efficient production, and auxiliary transport is not efficient mine production factors, how to

improve transport efficiency auxiliary transport system has become the key.

Early in the 1950s, foreign countries according to their specific situation began to

develop coal mine auxiliary transportation equipment to meet the working conditions of each

mine, improve auxiliary transportation mechanization level and productivity of the mine. To

the 1970s, the development of various types of coal mine auxiliary transportation equipment,

and maturing, a good solution to the problem of not supporting auxiliary transport such

auxiliary transport efficiency is improved. Currently, foreign technology mature new auxiliary

transport equipment there are four main categories: rail car, cog car, monorail and trackless

rubber tire vehicles, including monorail and rail cars used more often. Compared with the

traditional winch transportation, these new devices have traction, not a sports car, cannot

afford road, safe, etc., and mechanization mechanized mining mechanization mechanized

Driving adapt. Meanwhile, for the type of transportation of materials, design and manufacture

of specialized equipment, such as large transport flatbed truck when the tanker, vehicles and

other special vehicles and containers, application of these ancillary devices well done

underground auxiliary transport task such as transport problems mining area staff, which

greatly improves the efficiency of coal mine auxiliary transportation.

Development of coal mine auxiliary transportation is slow, the vast majority of mine is

still used by a small winch, small batteries and other components of the motor vehicle behind

multistage dispersion auxiliary transport system, there is a slow, links, low benefits,

occupancy and equipment and more personnel and security, adaptability and poor, difficult to

complete the shaft bottom or from the ground to the direct transport tasks face end, not suited

to large-scale mechanized mining of fully mechanized equipment, heavy-duty and Face Fast

installation, moving requirements, a serious impediment to coal production efficiency.

The overall technical level of domestic existing underground auxiliary transport

equipment, there is still a gap compared with foreign countries, many modern mine level is

not high, low production efficiency, equipment reliability, less secure, to change this situation,

to further strengthen Manufacturing of auxiliary transport equipment and modernization of

existing mines is not high modernize, has important significance. According to the actual

situation of the mine, a reasonable selection of a new generation of highly efficient auxiliary


transport equipment and auxiliary transport system has been modernized in order to gradually

lift the traditional auxiliary transport bound for mine construction and development, it has

become an important part in the future development of the mine construction . Monorail mine

locomotive as a new and efficient auxiliary transport equipment, with its advantages and good

adaptability, at our various mine auxiliary transportation more and more applications, get very

good results. Monorail mine locomotive operation safety can not guarantee the high reliability

from emergency braking system, the current majority of domestic manufacturers of monorails

mainly for production of a copy of a brake device according to the existing structure abroad

without their being involved in technical in-depth analysis of the problem, in order to adapt

the overall technological level monorail locomotive of Progress requirements, the need for

coal mine monorail locomotive emergency stop device for further study.

1.2 Current Research Situation about The Braking System_________

Monorail mine locomotive, with its advantages and good adaptability, used in various mines

in the increasingly wide range of Monorail locomotives mainly by the power source, brakes,

main cab, walking device support, traction devices, lifting beams and other parts of the

composition, running on the upper roadway suspended in a special I-beam track, traction

completed by the traction mechanism materials, transport equipment and personnel.

Monorail system mainly has the following characteristics: less demanding conditions for

roadway floor, ground without curing, adaptable; climbing ability, Diesel monorail up to 25 °,

can adapt to small turning radius, tunnel undulating environment In the frequent ups and

downs and big angle seam address conditions applied more widely; personnel transport tasks

can be done, to a certain extent, reduce labor intensity; equipment is simple, flexible, less staff

needed to maintain, easy to maintain; may the whole transport hydraulic support, without the

need to disassemble, runs trough, Face installation, high efficiency move; small transport

links, can be realized from the ground or the shaft bottom to stop the transport face not reprint;

track can be recycled, reused. Currently, Huaibei Mining Qinan Mine, Laws of choice

monorail diesel locomotives can complete the entire frame stand near 25t, climbing 24 ° slope

transport task, especially for complex roadway conditions and circumstances Face Moving,

working efficiency greatly improved equipment safety performance has also been guaranteed.

Xinwen Mining Group Suncun mine achieved using diesel monorails Face at longer distances,

a larger slope and complex geological conditions on the one-time delivery of materials and

equipment in place, eliminating the need for reprint links, making installation speed can be

improved, Face shorten the installation cycle, the pressure is reduced mine production

continue.

Common monorails run and Features

Depending on the power source can be divided into diesel-type monorail explosion,

explosion-proof battery type monorails and rope traction Monorail. Diesel monorail with

explosion-proof diesel as a power source, the circuit will be intensified by hydraulic pressure

to the drive wheels hanging rail webs, walking through the hydraulic motor. Another auxiliary

hydraulic circuit, complete locomotive emergency brake, safety brake and brake work.

Monorail has a small diesel engine, transportation, long distance, climbing ability, small


turning radius, range capability, strong carrying capacity and other characteristics, these

features make it more and more used in the mine. A monorail runs on multiple Face can be

achieved from the ground to the mining area or shaft bottom face direct transport, eliminating

the reprint links, complete normal transport personnel, materials, etc., in particular, hydraulic

support, etc. heavy equipment transport. Lu'an Environmental Energy AG Zhangcun mine is

China's first use of diesel monorail locomotive, so far retained direct transport from the

ground to the working surface of monorail transport system for mine modernization and

improvement of production efficiency has played a positive role.

Monorail battery is a battery power pack as a power source, a DC power supply inside

out through electrical control box of the inverter, the direct current into three-phase

alternating current, direct driven by explosion-proof motors drive wheels running on the

monorail track device, while driving through the auxiliary hydraulic pump motor, set up the

system pressure locomotive running the necessary to ensure the normal operation. Monorail

traction battery with a simple operation, low noise, environmental pollution…etc. Compared

with diesel monorail locomotive, equipment investment small, easy replacement of defective

parts; the use of lead-acid battery can be heavier than a small, limited life; short battery life,

battery life is generally not more than two years, the high costs required to replace the battery ;

its own weight, and small climbing ability, does not apply to long-distance transport.

Lithium-ion battery than the lead-acid battery has many advantages, along with the

development of lithium battery technology continues to mature, to lithium batteries instead of

lead-acid batteries as a power source monorail locomotive has a great advantage for battery

Monorail broader application provides new impetus.

Monorail wire rope traction components including drives, tractors, lifting beams,

reservoir rope drum, carrying cars, back to rope station, tensioning device, the safety brake

car, the connecting means, the suspension device, track, etc.. Promise rope winch traction use

monorails, between the rope and the drive wheels by the friction generated to drive the rope

run, makes monorail locomotive running back and forth along a suspended track to do to

complete the auxiliary transport tasks. Simple traction rope monorail structure, climbing

ability, low capital investment, mainly for Heading Face foot mountain, complete transport

materials, equipment and personnel. With increasing transport distances, plus the need to

increase a lot in the corners of the guide wheel and not bifurcated run, rope resistance,

resistance locomotive, rail carrying capacity will increase, so does not apply to rope pulling

monorail Long Distance auxiliary transport. Although China calls for the establishment of

large modern mine, but also many small and medium mines still exist for the realization of

auxiliary transport modernization, simple structure, small and flexible, efficient monorail

locomotive traction rope there is a great use of space. Use rope tow monorail can solve small

auxiliary transportation links, a large labor intensity, equipment transportation difficulties and

low security, lower cost increase productivity largely mine.

Since the monorail auxiliary transport equipment with advanced technology, operational

flexibility and efficiency, etc., used in the United Kingdom, the Czech Republic, Germany

and Australia, and other countries with advanced mining technology is widely used. Germany

since 1940 applied the first rope tow monorails, so far, by the monorail auxiliary transport

tasks accounted for over 90% of the total transport auxiliary assignments. Currently, the

monorail equipment used in many domestic mines are from Scharf companies. Czech began


to study the auxiliary transportation mechanization in 1950, mostly because of their domestic

mine seam, roadway layout complex, cross more serious floor deformation, the slope is not

greater than 25 degrees and toward small length, not applicable trackless rubber tire vehicles

and rail cars transportation, so the Czech Republic mainly by the diesel traction assist

monorail transportation system, there are more than 2,000 underground diesel monorails bear

primary auxiliary transport task. In the Czech Republic renowned monorail manufacturers

have 芬瑞特 Company and Star Steve companies.

At present, foreign countries have eliminated the rope tow monorails, major development

and production of batteries and diesel traction Monorail. Due to limitations in current battery

technology, battery energy storage per unit volume less locomotive run a short distance on a

single charge, the need for frequent battery charging. Powered by a diesel monorail

explosion-proof system needed to run the diesel engine, power, performance, ramp angle is

relatively large, and therefore the main development direction of foreign diesel monorails.

Currently, state and foreign mining technology has advanced compared our auxiliary

transportation equipment there is a large gap, there are many small and medium mine is still

used in small battery electric locomotive, winch and other multiport relay backward mode of

transport, which there is a kind of auxiliary transport running slow, transport links, low

security, personnel and equipment to use and more poor adaptability, low efficiency and other

issues. Especially in the face in moving, relocation workload, the process is complicated,

time-consuming, resulting in a serious impact on coal production efficiency and safety.

For in mine auxiliary transportation problems of domestic coal mines have been using the

new device's own auxiliary transportation system reform, a lot of which is the use of

monorails. At present, the country has a battery monorails manufacturer, there is no diesel

monorails manufacturer, diesel monorail lifting auxiliary input systems are used in each mine

through imports. Zhangcun Mine is the first completed monorail using underground coal mine

auxiliary transportation tasks, the mine can be achieved along the slope of 6 °, length of

1438m is inclined to heavy hydraulic arm, or other material directly transported to face the

task auxiliary transport links greatly simplified, significantly improve efficiency.

Since 1950 our country began to introduce and study design auxiliary transport

equipment, and in 1979 to resolve the Mechanized Roadway in material handling issues, from

the introduction of West Germany's first monorail locomotive traction rope, but since we had

a small area roadway that does not resolve the problem and did not stand reinforcement put

into use. In 1982, Hebei Province Coal Institute developed the FND-40-type internal

combustion engine monorails, but because they did not solve the problem and makes it

difficult element explosion application. In 1986, Henan Province Coal Institute developed the

GDD-140 type rope tow monorails, mainly for Mechanized Roadway charged to protect the

material transport, and in 1987 passed the technical appraisal of the Ministry of Coal, we have

to promote the use of 3 Taiwan. In 1987, the Institute of Henan Province Jiyuan coal

switchgear plant jointly developed the XTD-7 proof monorail traction batteries, successfully

applied to seven minePingdingshan Mining completed Mechanized Roadway in materials,

equipment and other transport tasks.

At present, China has adopted a number of mine monorail transport equipment to

complete the underground auxiliary transport missions, monorail diesel locomotives and

locomotive batteries used more monorail, monorail locomotive traction rope is seldom used.


Monorail diesel locomotive primarily in use today is imported from Germany Star Steve

Scharf Group Company and the Czech Republic 芬瑞特 company, there are no

manufacturers. Battery monorail locomotive few domestic manufacturers, mainly in

Shandong Sinsa monorail transport equipment and Shijiazhuang Coal Mining Machinery Co.,

Ltd., the former Shandong Founding Scharf Group and Germany's joint venture, which are

produced mainly in Funchal monorail husband of technology; the latter is the Central Coal

Group and Jizhong Energy Group common shares of state-owned joint venture company, has

a good working relationship with Tsinghua University, Beijing Institute of Technology and

other famous universities.

Monorail research status at home and abroad passive emergency braking system

Currently in coal mine monorail transport system mainly traction batteries and diesel traction

monorail monorails, rope pulling less monorail applications, where mining technology in high

levels of foreign countries have been eliminated. Each stage proof diesel and battery monorail

monorails are made active emergency brake and brake and emergency brake work using the

same set of brake control device, but rarely in research and application of passive emergency

brake passive emergency brake device is mainly used in rope pull monorail braking. Maarten

in 1986 to explore the rope tow Monorail random braking was summed up three common

passive rope pulling emergency brakes, and that the ZGZ type compared with the same type

of foreign braking device, there are obvious advantages such as low cost, small size, good

processing technology. Tow rope monorail three passive emergency brake mechanism

suspending the structure diagram shown.

Self-energizing brakes (Drum Brakes)

Figure 1.1The brake mechanism of self-increasing power

1. friction block base; 2. unloading bolt; 3. the brake friction block; 4. compression spring; 5.

connecting rod; 6. lever; 7. centrifugal governor; 8. the brake frame

When the monorail locomotive speeding, centrifugal governor increased 7 two centrifugal

ball centrifugal force, pulling the lever 6, so that the connecting rod 5 relieve pressure, brake

block compression spring 3 under the pressure of the friction block pushed back and

engagement with the base, with the locomotive to move forward, the pressure increases


between the two wedges, friction will cause friction between the block and hanging rail web

is gradually increased, ultimately braking. This kind of structure does not require additional

power source braking pressure provided, it is with the brake friction wedging block

implemented, the greater the amount of wedging, positive pressure rail web and the greater

the friction between the blocks, the obtained the greater the braking force.

Figure 1.2showing the explosion view of a standard Self-Energizing brake

Advantage of this structure is that smaller, lower cost, but there is a big disadvantage, if

they can not function in the reverse movement; because it is self-energizing brake can not be

adjusted according to the traffic, the braking force may cause so large that the harm to

personnel. GDD-140 monorail locomotive traction rope adopted this kind of self-energizing

brakes.

Eccentric friction brake (Disc Brake)

Figure 1.3The eccentric gear brake mechanism

1, cam friction block; 2, connecting lever; 3, connecting rod; 4, the guide sleeve; 5, wire rope; 6, the

slider; 7, the spring guide bar; 8, compression spring; 9, the adjusting nut; 10, unloading mechanism

Eccentric braking: When the rope off the rope for some reason, the compression spring 8 in

the role of guide rod guide 7, push the slider 6 drive link 3, link lever 2 causing friction block


eccentric 1 to rotate counterclockwise, Random car move, the two eccentric webs hanging rail

for positive pressure is gradually increased, eventually brake. This structure is mainly used for

carrying small monorail locomotive brake.

Clamp the friction brakes

Figure 1.4 Standard Clamp Brake

Figure 1.5The clamp friction braking mechanism

1,brake block; 2, the brake arm; 3, the return spring; 4, the boss-shaped energizer blocks; 5, hydraulic

cylinder; 6, the compression spring; 7, centrifugal governor; 8, a joystick; 9, Hydraulic brake circuit

Braking: When speeding occurs and the speed reaches a certain value, the centrifugal

governor 7 action, 8 joystick trigger unloading valve operation of the hydraulic cylinder 5

unloading, boss-like block brake booster compression spring 6 under the effect of upward

pressure out through the brake block brake arm pressed against the track in order to achieve

braking. Just shake your hand when you loose brake pump to supply hydraulic pressure, the

brake spring compression, two brake arm to its original position by the return spring 3 role.

The species characteristic of the braking mechanism are: speeding locomotive forward

and reverse can be done when the brake; braking process either manually or automatically; by

adjusting the spring and the hydraulic cylinder can be achieved on the braking force

regulation, there is conducive to optimizing the performance of the braking device; lock when

there is a higher hydraulic oil, likely to cause leaks and spontaneous braking, so the higher the

tightness of the hydraulic system requirements.


1.3 Main Research Contents and Research Significance____________

Application Status by analyzing this topic monorail locomotive in coal mine auxiliary

transportation system and application development trends, to design a study to determine the

need for and feasibility of monorail with higher reliability passive emergency braking device,

then According to structural analysis and design optimization of target parameters to calculate

the required emergency brake, and with the relevant software to complete braking system,

emergency braking process research. Specifically, the main contents of the research are:

(1) Analysis of common Monorail braking device structure at home and abroad, working

principle and characteristics, summary of national standards for mine auxiliary transportation

vehicle emergency braking device, in particular for monorail locomotive requirements; learn

from some of the world-renowned Monorail manufacturer of brakes business practices, such

as Germany Scharf company, design a highly reliable passive emergency brake.

(2) some of the existing monorail hydraulic control system analysis, extensive access to such

information, in accordance with actual down hole environment, setting norms and questions

should be noted monorail hydraulic system design should follow, and design a passive

emergency hydraulic brake system control loop.

(3) summary service brake friction materials, analysis of factors frictional force during

emergency braking, the friction heat generated wear mechanism and brake mechanism blocks

to guide the right choice for brake friction material, while the brake frictional heating during

analysis of the phenomenon.

(4) of the speed limiting device research. Establish centrifugal release simplifies mechanical

model, and with the virtual assembly technology to complete system modeling, simulation

using the sliding ADAMS different displacement speeds of the shaft extension, to determine

the trigger switch arrangement area theory under certain circumstances, to a certain extent, the

initial spring compression research the amount projected impact shaft displacement curve of

the slide, while guiding the selection or design to take reasonable speed wheel diameter.

(5) the use of three-dimensional solid modeling UG NX6.0 complete primary structure of the

braking device, and by means of the finite element simulation software brakes key member

statics analysis and structural optimization, such as brake calipers, brake lever.

(6) of the brake block and the web contact process research. ADAMS use of variation during

braking lever and rack sleeve gap between research, analysis contacting law summarized

brake block and the rail web and propose improvements.


2 Overall Design of The Monorail Emergency Braking System_____

2.1 Elementary Theory and Design Requirements of the Monorail

Braking System_____________________________________________

Monorail mine emergency brake Overall Structure Design

Coal production process, shall be equipped with the monorail locomotive orbit emergency

brake to avoid speeding, rewind slip phenomenon appears vehicles. Unstable load operation

often leads to fluctuations in the braking time, when the power system can not provide

sufficient power for the braking system, it will also lead to increased braking time or to

increase the slippage distance, sometimes even sudden power status locomotive causing

runaway locomotive, which can give the lead to accidents, thus Based on the existing

emergency brake active research on the design of a monorail locomotive passive emergency

brake, and its hydraulic control loop planning.

Germany Scharf brake clamp structure (school type)

Germany Scharf brake clamp structure of the main structure and hydraulic brake pneumatic

brake structure, the two structures have their advantages and disadvantages, the wider

application.

Figure2.1 The pneumatic brake mechanism

Figure 2.1 shows Scharf's pneumatic brake structure, which consists of a cylinder, the system

springs, brake calipers, brake rack, friction blocks and other components. Brake calipers and

the friction block is directly connected to the braking pressure directly from the brake caliper

to the track. Features are: spring brake cylinders arranged separately from the system, in order

to obtain a larger layout space, longer brake calipers long rod with cylinder attached.

Although the cylinder stroke is relatively long cylinder, but it moves fast unloading, it can

make a long journey to bring the braking response time lag to some extent.

Figure 2.2 Three poles hydraulic brake mechanism


Figure2.2, To Scharf three hydraulic brake rod structure, which consists of parts of the

brake caliper, brake lever head, brake springs, hydraulic cylinders, rod, friction block, frame

body and other components. This kind of brake form hydraulic brake spring inside, to a large

extent reduce the space requirements. Braking, for unloading hydraulic cylinder, brake

calipers under spring pressure by the brake lever, the brake lining is pressed against the rail.

In this process, the support bar by a pin and the bracket body is connected to and rotates

with the brake caliper lever and the strut is connected to the head through the pin, the brake

caliper for rotation plane, such that the sleeve along the rod on the frame body movement.

Compared with the brake cylinder structure, a triple rod brake braking force structure,

the overall structure and other characteristics, with its advantages of this structure in domestic

and foreign manufacturers more often

Emergency braking device body structure design

Monorail mine in accordance with the power source can be divided into rope pulling

monorails, explosion and diesel traction battery monorail Monorail. Whatever the form of the

monorail, are required in accordance with the relevant requirements of the national standard

emergency brake. Some manufacturers emergency brake and parking brake work by the same

brake system is completed. Monorail mine auxiliary transportation system during transport

personnel and cargo, it is necessary to brake the car carrying security. The design with rope

pulling monorails as an example, its emergency brakes, also be applied to other monorail

transport system.

Tow rope winch monorail transport system is driven by rope traction with traction, small,

small turning radius, climbing ability, transportation safety and reliability. Transport material

and personnel can also be used to transport hydraulic support and other heavy equipment.

Track adoption I140E type beam, suspended from the ceiling on the use of the tunnel roof, for

easy removal. In the roadway floor conditions are not good and gradient changes in the larger

case, more suitable for use in the transportation system. The device is a high degree of

automation, simple operation, various protection functions, safe and reliable operation. When

speeding or other accident occurs, the brake is automatically braked to avoid the derailment or

coasting phenomenon occurs. Locomotive traction rope monorail system includes traction

rope car storage, safe braking car, lifting beams and various types of vehicles, can be a

random combination of vehicles depending on the transport task.But as long as the materials

involved in the transport of persons or equipment, it must be matched according to size

selection emergency brake traction. Emergency brake device consists of brake calipers, brake

beam, friction plate, rod head, hydraulic, compression springs and other components, by press

release brake, spring brake complete unloading emergency brake locomotives to ensure

personnel and equipment safety.

Mine Monorail emergency brake Overall Structure Design

Coal production process, shall be equipped with the monorail locomotive orbit emergency

brake to avoid speeding, rewind slip phenomenon appears vehicles. Unstable load operation

often leads to fluctuations in the braking time, when the power system can not provide

sufficient power for the braking system, it will also lead to increased braking time or to

increase the slippage distance, sometimes even sudden power status locomotive causing


runaway locomotive, which can give the lead to accidents, thus Based on the existing

emergency brake active research on the design of a monorail locomotive passive emergency

brake, and its hydraulic control loop planning.

Present common monorail brakes

Stage coal mine monorail braking mode, the vast majority use clamp friction braking mode.

Mine production abroad Monorail business units are: Germany SCHARF (Scharf), Czech

Republic Ferrit (FenruiTe), Czech STAVUS (Star Steve), they all have their own independent

braking structure. Monorail domestic manufacturers are: Founding Shandong Machinery

Equipment Co., Ltd., Shijiazhuang coal, brakes are used also learn from foreign

manufacturers more experience, more applications are in Germany and the brake mechanism

Scharf Czech FenruiTe brake mechanism. Emergency braking mechanism of these

manufacturers are mostly active in walking on their own monorail locomotive more

applications, such as monorail locomotive traction battery explosion, explosion-proof

monorail diesel locomotive traction, while the monorail locomotive traction rope seldom used.

In this paper, the current structure of some manufacturers use the brake is analyzed and

summarized their working principle and characteristics.

Germany Scharf brake clamp structure

Germany Scharf brake clamp structure of the main structure and hydraulic brake pneumatic

brake structure, the two structures have their advantages and disadvantages, the wider

application.

Scharf's pneumatic brake structure, which consists of a cylinder, the system springs,

brake calipers, brake rack, friction blocks and other components. Brake calipers and the

friction block is directly connected to the braking pressure directly from the brake caliper to

the track. Features are: spring brake cylinders arranged separately from the system, in order to

obtain a larger layout space, longer brake calipers long rod with cylinder attached. Although

the cylinder stroke is relatively long cylinder, but it moves fast unloading, it can make a long

journey to bring the braking response time lag to some extent.

Three poles hydraulic brake mechanism

To Scharf three hydraulic brake rod structure, which consists of parts of the brake caliper,

brake lever head, brake springs, hydraulic cylinders, rod, friction block, frame body and other

components. This kind of brake form hydraulic brake spring inside, to a large extent reduce

the space requirements. Braking, for unloading hydraulic cylinder, brake calipers under spring

pressure by the brake lever, the brake lining is pressed against the rail. In this process, the

support bar by a pin and the bracket body is connected to and rotates with the brake caliper

lever and the strut is connected to the head through the pin, the brake caliper for rotation

plane, such that the sleeve along the rod on the frame body movement.

Compared with the brake cylinder structure, a triple rod brake braking force structure,

the overall structure and other characteristics, with its advantages of this structure in domestic

and foreign manufacturers more often.


Domestic common monorail detent

At present, the research Monorail brakes less, some manufacturers mainly some foreign

braking mechanism, Figure 2.4 for the monorail brakes Transport Equipment Co., Ltd.

Shandong Sinsa monorail used. The company is a German company with Shandong Scharf

Founding Machinery Equipment Co., Ltd. jointly funded the establishment of Sino-German

joint venture, the company produced monorail Scharf brake structure uses three hydraulic

brake rod structure.

Shijiazhuang Coal Mining Machinery Co., Ltd production of rope pull monorail car used

in the safety brake and carrying crane structure is basically the same, but in each of the

support rollers provided with a brake cylinder. Need brake, brake cylinder pressure relief, the

piston moves in the spring push, which will support the friction brake blocks within the wheel

brake pressure to achieve orbit webs. The brake system reduces the structure size brake the

car, but the complex structure, with respect to the brake lever is get the same positive pressure

on oil requirements, more likely to cause leakage.

2.2Selection of Brake Actuator______ __________________________

GB in the braking system of monorails requirements

Ministry of Coal Industry of the approval in 1996 of the standard MT / T591-1996 "coal mine

emergency stop device", the State Coal Industry Bureau issued a standard MT in 2000 /

T886-2000 "coal mine traction rope Monorail" and MT / T883-2000 "monorail diesel

locomotive", their mining monorail locomotive brake system is mainly made up of the

following requirements:

1, monorail locomotive vehicle requirements

Each monorail transport equipment, be equipped with 1 to 2 sets the emergency brakes, and

the braking force of not less than 1 5-2 times the sum of the nominal traction. Each brake

device an automatic speed limiting device must be installed, which allows for manual brakes

both brake application, but also to achieve automatic brake application.

2, the brake system performance requirements:

(1) braking device must have a high reliability, it should be equipped with either manually,

but automatic, fail-safe braking system. Braking device must have the following properties:

① locomotive traveling faster than 15% of rated speed automatic brake application,

when the rated speed of not more than 2m / s, allowing time to run faster than 30% of

rated speed automatic brake application, the brake system should be flexible and reliable;

Lost motion time

②brake application time should not exceed 0.7s;

③When the locomotive to the maximum load maximum design speed down the run at

the maximum slope, the braking distance shall not exceed the equivalent of running under 6s

distance in this speed;

④when the locomotive up to the minimum load traveling on the maximum gradient,

braking deceleration is not exceeded.


(2) hydraulic system pressure at 125% of rated pressure, packing 5min and not have leakage.

After 36h dwell under the rated pressure, the pressure can be maintained when the normally

open brake blocks required.

Centrifugal release

(3) braking device used in the operation must be guaranteed to always face engagement and

rail, for which the general should set up two sets of the same structural performance

centrifugal releaser.

(4) brakes at maximum load, the provisions of the main parts of the rear brake brake on the

maximum design gradient may not cause permanent deformation.

3, on the friction brake pad material antiknock requirements:

Monorail use of polymer products should be flame retardant and antistatic properties, and

comply with the MT113. Brake block braking device material should be used in combustion

and detonation does not occur when the brake made of a material.

4, the relevant test requirements:

Germany Scharf Group requirements for brakes

Scharf Group since 2003 to enter the Chinese market, has gradually to Shandong Xinwen

Group, Shanxi Lu'an Group, delivered dozens of sets of different types of diesel monorail

locomotive, it has been recognized by the users. Monorail braking means the company has a

high reliability, some domestic manufacturers also use it some structure, three rod hydraulic

braking system as adopted by the Group of Shandong career. The company produced

monorail braking device requires periodic measurement and testing, generally measured about

two months apart, the main contents include: Check the brake calipers holding force;

geometric characteristics Check the brake calipers; check the brake calipers length of the

spring; contact force checking brake calipers; check centrifugal starter; machine checks the

boot situation by centrifugation start; check emergency stop means.

1. Check the brake caliper geometry

1) The thickness of the brake pads redundancy least 7mm (new to 10 mm), if worn friction

plate after less than 7 mm need to replace a new brake lining;

2) When the brake release state, maximum lateral displacement of the bracket between the

sleeve and the brake lever is 2 mm;

3) The maximum distance between the roller and the holder is 114 mm;

4) The brake lever are arranged symmetrically, when the brake lever to lift the track surface,

on each side of the brake pad and track a minimum clearance of 26mm;

5) The brake release process and the braking process, the brake lever head can not stand

against the sleeve;

6) increase, under power, can not resist the brake lever bracket, should a gap, the gap is no

greater than 3mm.


2. Check the brake spring length

1) must be closed in the brake caliper brake status, the brake spring length measurement,

brake lining minimum thickness of 10mm (new);

2) to measure the true length of the contact spring and the contact surface between the surface

of the disc, in the new spring brake lining length of not more than 495 mm.

3) In any case, no contact with brake, brake because at any moment may close

Figure 2.3 Sketch diagram of geometrical features Figure 2.4 The sketch diagram of spring length

2.3Selection of Speed Detection Mechanism______________________

Speed test;

(1) of the centrifugal governor

Tachometer using centrifugal governor on a dedicated test equipment, the centrifugal

governor rotor rotation, when the governor action, recording operation speed value, the test

five times, the measured value tolerance of 5% of the predetermined value taxis.

(2) braking device in space-time dynamic brake application time trial

Use the lost motion tester operating handle (or release valve) and brake shoe at each posted a

platinum metal makes contact and the tester is turned on, the lost motion time will be

displayed on the operating handle brake tester.

2.4.1 Selection of Friction Material_________________ ____________

Common brake friction materials

Friction block according to the different materials can be divided into two metals and

non-metallic, metal friction block including (copper, iron) powder metallurgy friction block,

friction blocks high-speed rail and high-carbon austenitic steel; non-metallic type friction

materials include non-asbestos friction materials and asbestos friction material, wherein

non-asbestos friction material also contains semi-metallic, inorganic fiber-reinforced, organic

and inorganic fiber-reinforced type.

For a long time, since asbestos has good heat resistance and good mechanical strength,

asbestos materials are widely used in conventional vehicles and drive machinery. Products are

mainly made by the asbestos brake pads, brake band, brakes, etc., in the field of mining


machinery more applications are compiled asbestos brake pads, divided into two kinds of oil

and resin. Domestic production of asbestos brake pads mainly as a reinforcing material, and

with a phenolic resin binder, special packing, through the membrane made of plastic

composite materials, automotive brakes in large load more applications. But asbestos

environmental pollution, easy to dehydration and unstable at high temperatures, especially

those with a significant impact on human health, many countries have banned the use of such

materials. Common asbestos-free friction materials are glass fiber reinforced type friction

materials, carbon fiber reinforced type friction materials, the former speed, load and

temperature sensitive, prone to wear; overall performance which was significantly higher than

the former, especially in high temperature conditions Under able to maintain a high

coefficient of friction and wear rate is relatively low, but the current high costs, limited to the

preparation of our country.

Friction materials obtained by sintering powder metallurgy technology, also known as

friction materials, mainly copper, aluminum, iron-based categories, this material has a high

strength, stable friction coefficient, wear resistance, less environmental pollution. Among

them, the aluminum low friction material point of combustion, surface susceptible to

oxidation, and easy to produce sparks, generally can not be used in the mine. In addition,

copper-based friction material also has good thermal conductivity, wear resistance, corrosion

resistance, and other advantages; compared to the iron-based copper-based friction material

friction material having a higher heat resistance and coefficient of friction, and therefore dry

friction It is widely used under heavy load conditions.

Emergency brake block friction Phenomena

Emergency braking, also known as safety brake means that in the event of an accident or

sudden accident, the braking device can be realized to meet the relevant provisions under

braking conditions, avoid property damage or casualties. Currently, brake pad materials

research is mainly aimed at cars, trains, planes, etc., and the underground car monorail

locomotive brake emergency brake friction material is relatively small study, in order to

further improve the underground monorail transportation security, to emergency braking

conditions monorail research brake block friction and wear properties of materials important.

In the monorail locomotive during emergency braking, the hydraulic cylinder unloading, the

spring pressure through the link mechanism is pressed against the brake block beam hanging

rail, locomotive kinetic energy into heat energy consumed, in order to achieve braking. Since

the locomotive weight, and braking time is short, the emergency braking process will produce

a lot of heat can not be distributed and attached to the surface, resulting in brake block surface

temperature, easy to produce sparks. At the same time, the temperature can not be lowered in

some brake block material properties will change, likely to cause braking performance

degradation, such as lost motion time increases. Therefore, a reasonable selection of brake

block material of great practical significance to ensure the reliability of the emergency

braking device.

Emergency brake friction factors

In actual monorail locomotive braking, the braking force is provided by friction brake blocks

with hanging rail web between the braking effect depends directly on the brake block braking


tribological performance parameters, and these properties Parameters affected by many

factors, including a positive pressure, temperature, speed, etc.

Effect of braking force :

(1) positive pressure. Many manufacturers work Monorail brake and emergency brake are

using the same set of devices, although the braking process takes shorter braking pressure still

take some time to reach the maximum. The brake pressure is increased in the process can be

divided into three phases, in periods of low pressure, increase the brake pressure will increase

the actual surface contact area, in the pressurization process, on the surface asperities mutual

engagement, collision until fall, portion of the filler particles and the matrix binding is not

strong will fall from the surface, thereby generating wear. As the pressure increases, the effect

of this surface asperities will strengthen the engagement between the collision, shedding more

abrasive amount, resulting in friction increases, but because of the low brake pressure, and

therefore increase the amount of wear It will not be obvious. After entering the medium

pressure stage, the actual contact area between the shoe material has increased to a relatively

stable value, depending on the contact surface of the frictional force at this time a large area

of the contact between the adhesive effect of the film, as the pressure increases, Adhesion -

tearing effect will be enhanced, thus leading to increased friction, adhesion - influence tearing

action on the brake shoe material is more obvious than the engagement of the low pressure

stage of asperity, so the wear rate of speed. In the high-pressure stage, a heavy load for a large

area on the stage of the brake shoe contact film formed on the surface of the material damage

caused to crack, touching film is peeled off from the surface will be crushed, the actual

contact area will be reduced again, so friction factor becomes low, while shedding a direct

impact on the surface of the film thickness variation brake shoe, thus resulting in a sharp

increase wear rates.

Comprehensive view, when the brake initial velocity is constant, with the increase of the

brake pressure, the average coefficient of friction brake shoe material will be increased, then

decreased, and the stability of the friction coefficient of the overall downward trend was; the

wear rate is increasing, and in the low-pressure phase material wear rate of growth is slow,

but after entering the high pressure stage, the wear rate of increase has accelerated noticeably.

Thus, the reasonable selection of brake pressure, not only affect the performance of

brake shoe friction material, its degree of deterioration and wear properties have a great

relationship. Within a certain range, increasing the brake pressure brake shoe material will

help to improve the friction coefficient, the wear rate can be maintained within a reasonable

range, but the high performance friction brake pressure so they will decline, while increased

wear and tear of materials, which is reasonable for the site selection braking pressure is a very

important issue .

(2) the temperature on the brake blocks. Given the temperature of the brake block friction and

wear properties of materials directly affected and may cause abnormal changes, thus

increasing brake pressure, we should also consider taking appropriate measures to reduce

brake shoe surface temperature rises, design allows for heat dissipation as a surface structure

for brake blocks.


(3) the running speed of the braking process. With respect to the automobile brake, coal mine

monorail locomotive speed is generally low, under positive pressure and brake shoe material

conditions determined little effect on the braking force.

Mechanism of heat generated by the emergency brake friction analysis

From the perspective of energy conversion, emergency braking process is actually an energy

conversion process, the braking device will monorails the kinetic energy in a very short period

of time is converted into heat and dissipated. With the development of high-yield and efficient

mine construction, carrying capacity auxiliary transport equipment gradually increased, which

means more heat is generated in the emergency braking process. Monorail brake blocks for use

in terms of material, will lead to high-temperature friction material of the organic component is

thermally decomposed, thermally crosslinking, oxidation, burst melting, evaporation, and

sublimation and a series of physical and chemical reactions, the reaction rate with the

temperature exponentially increase. Practice has proved that theory, failure or damage the

friction material is mainly due to the high temperature generated by friction surfaces, excessive

temperatures will cause the material surface a series of physical and chemical changes,

resulting in decreased braking performance, enabling the device to run lower safety factor. The

physical properties of friction material, positive pressure brake lever head, friction material

design structure and size, operating conditions and environment can affect the friction material

surface temperature. Emergency brake shoe friction and heat for analysis, will contribute to a

reasonable choice of friction material, and to guide the design of the friction surface structure to

some extent.

Emergency brake block friction and wear analysis

Monorail locomotives generate an emergency braking friction between the friction material

and the I-beam rails to achieve kinetic energy through friction, potential energy converted to

heat, friction force determines the conversion speed. Friction between the friction surface

between the rail and the friction material would cause the contact surface material loss and

transfer, which creates wear. Wear so that the distance between the rail brake block friction

becomes large, the brake reaction time and amount of pressure has a significant positive

impact on, when the wear reaches a certain level, you can not guarantee the reliability of the

emergency brake, then brake blocks must be replaced. Wear mechanism analysis, it helps

block gate structure design stage to take certain measures to reduce wear and extend the life

of brake blocks to ensure the reliability monorail braking device.

Monorail locomotive brake friction braking apparatus belongs, at work, Friction type is

dry friction, its movement type is sliding friction. According to modern solid friction theory,

it is believed the friction brake consists of three parts: First, when the brake block and the

guide rail relative movement between the two intermeshed peak asperity friction between the

collision and the formation of (mechanical action force); the second is in a certain local high

temperature and high pressure stress, friction asperity local plastic deformation will occur, the

instantaneous formation of the contact point sticking point and the friction relative movement

of the pair has forced separation of these local bond, These nodes are bonded to overcome

resistance constitutes a part of the friction (adhesion friction); the third is hard particle

abrasion or friction surface, the friction during movement pushed the friction surface and


form a new asperity, continue to generate friction surface cutting, plowing role, which also

form part of friction (furrows force). Therefore, the brake friction can be expressed as.

321 FFFF (2.1)

Where，

F —— Brake friction，N

1F —— Engaging deformation resistance，N

2F —— Adhesion resistance，N

3F —— Furrows resistance，N

For further research and analysis generated by the friction brake mechanism, the frictional

force will pose the following fundamental factors, namely adhesion, engage and furrows three

friction component analysis and study .

（1）Adhesive friction

Due to the surface roughness, when contact between the brake blocks and the I-beam track,

the real contact only occurs in the top handful of asperity, shown in Figure 3.2. The real point

of contact occurs is called the real point of contact, the sum of all the contact points of the

contact area is called the real contact area. Obviously, the real contact area only accounts for a

small part of the design of the contact area. Under braking pressure, the compressive stress at

the contact point will reach peak compression brake block material yield limit s ，Plastic

deformation, leading to adhesion (otherwise known as cold welding) phenomenon. Due to the

more compressive friction soft material yield limit s Determine the stress at the contact

points, so in a state of static friction, friction of the real contact area can be expressed as:

sPA /0 (2.2)

where，

0A —— The real contact area of a static friction state, m2 ;

P —— Brake pressure, N;

s —— Brake Materials compressive yield strength, Pa


Figure 2.5 Rough peaks contact model

When there is relative sliding between beam rails and brake shoe, due to the presence of

shear force, the sticking point will occur plastic flow, increase the contact area, shown in

figure. Therefore, the sliding friction state, the contact point deformation conditions and the

real contact area that is dependent on normal load brake pressure shear stress and shear stress

generated by the combined effects of pressure. According to the revised adhesive friction

theory, the real contact area available for the sliding friction state：

220 )()(

b

t

s

FPA

(2.3)

therefore，

0A—— The real contact area of the sliding friction state, m2

tF —— Tangential force, N

Figure 2.6 The slide of the sticking points

Relative movement, sticking friction 2F Relative movement, sticking friction...

bAF 02

(2.4)

where， b — Shear strength adhesive junction，Pa。Intensity of a variety of factors


ranging size and surface materials, surface cleanliness, temperature and other related material.

（2）Frictional engagement

When the I-beam rail in contact with the brake shoe friction relative motion, since the

contact surfaces is smooth, due to mechanical engagement, the contact surface will produce

distortion resistance. For the metal-to-metal friction, mechanical deformation resistance of

small, usually negligible, but the brake deputy from the metal rails and a resin-based

composite friction material, wherein the surface deformation and hysteresis loss of the resin

matrix composites resistance caused by the friction of the important parts. According to Gail

Chomsky carat mechanical - molecular theory, engaging obtained deformation resistance 2F

To：

)(2pBASF mmm

(2.5)

where，

mS — Mechanical engagement of the area，m2;

mA — Mechanical engagement of the tangential stress，Pa;

mB — Normal load influence coefficient;

p — Normal load, namely stress，Pa;

a — Index, which tends to a value of not more than 1.

（3）Furrows friction

Hard filler particles during braking, brake blocks on the surface and the substrate binding is

not strong will gradually fall off from the surface, part of the residence between the contact

interface, embedded in the friction surface under pressure to form a new asperity, push the

brake shoes during braking surface material, to produce plastic flow and plow the groove, as

shown in Figure 3.4. For Monorail brake, because the impact of the underground environment,

between the brake blocks and the rail most of the time is not smooth, furrows serious.

Figure 2.7 The furrow model


Assume hard asperity is composed of many apex angle 2 h Cone composition, the

role of the normal pressure, hard asperity material embedded in the surface of the brake shoe

depth，In the process of sliding friction, only in contact with the brake shoe material Frontier

surface of the cone. Therefore, the contact surface area of the vertical projection plane as:

2

dhS

(2.6)

If the plastic yield performance brake block is isotropic, and the yield limit of s ，Then the

friction effect in the furrow to 3F ：

ss dhSF 2

13

(2.7)

These are based on the basic principles of modern solid tribology, an analysis of the

friction brake of the basic factors. In fact, the braking process shown by the friction i

s the result of the combined effects of various forms of friction generated in the peri

od under different conditions and different effects on various aspects of brake friction.

2.4.2 Emergency brake friction materials selection ______

Variation brake friction analysis

Constituted by the front brake friction analysis shows that during the three emergency

brake friction components are: mechanical engagement friction surface asperity deforma

tion force between 1F、Adhesion local contact points - Cut friction 2F 、And hard par

ticles furrows cutting force 3F During braking, due to different working conditions, th

ree different frictional forces will change, and change may appear abnormal, and then

at the macro performance of the friction coefficient gradients and mutations.

The size of the friction adhesion and adhesion junction of major shear strength a

nd the real contact area concerned. In the initial stage of the brake, the surface frictio

n of the relatively rough, sticking only occurs on a few points of contact, so that the

adhesion - shear generated by the friction is relatively small; with the brake progress

es, the friction surface reduce the number of asperity, the actual contact area will incr

ease, adhesion occurs in the larger contact area, so there are more obvious adhesion r

esistance increases. Under normal braking conditions, brake block material properties i

n the normal state, the shear strength of the adhesive area is more stable, sticking fri

ction change depending on changes in actual contact area, which is in gradual stages.

After several continuous braking, the surface temperature of brake block material will

be resistant adhesive material reaches the limit, the cladding material is in a softened

molten state, at this time will be drastically reduced shear strength adhesive junction,

Therefore, mutations can cause sticking friction.


The mechanical deformation frictional engagement of main components: brake pres

sure tangential component and tangential resistance. In the initial stage of the braking

surface friction is relatively rough, asperity occurs more engaging, and with the brakes

were rough asperity gradually reduce the number of bodies. Therefore, the engageme

nt initial deformation resistance of the friction brake only play a major role, with the

extension of its value gradually reduce braking time, this is a gradual process.

The size of the main furrows friction with hard particles furrows area and brake

block material yield limit exposure related. Furrow contact area is determined by the

hard particles size, shape and number, its range is very limited, so the yield limit bra

ke block material has a decisive influence on the furrows friction. When the nature of

the material is in the normal brake block, which has a relatively stable yield limit v

alue, so that the friction in the normal state, furrows friction changes minimal. But w

hen the brake block surface softened, melted, it will drastically reduce the yield limit,t

hen furrows resistance mutations may also occur.

Based on the above analysis of brake friction variation of the basic elements, whi

ch can be seen: the deformation generated by frictional engagement generally work on

ly in the initial stage of the brake, there is a gradual process of change, and the adh

esion and friction furrow friction braking process in the whole work, and both are lik

ely due to changes in material properties and mutates. Therefore, during the majority

of brake friction, play a major role in the adhesion friction and friction furrows are li

kely due to mutations caused by mutations in the occurrence of the braking force. Mo

norail stage many manufacturers are working with the brake, safety brake and emerge

ncy brake are used with a braking mechanism, bad brakes and brake frequently enviro

nment, it is necessary to choose a reasonable brake block material to ensure braking s

tability and reliability.

2.4.3 Emergency brake friction materials selection_____________________

Through the front brake friction braking friction factors and analysis of the phenomenon can

be drawn:

(1) monorail locomotive braking system has the kinetic and potential energy is converted into

heat in a short time the friction generated by Deputy Commissioner, small contact area, will

produce a high temperature. At high temperatures, some of the powder metallurgy materials,

composite materials prone to degradation, wear serious problems, which can affect the life of

the friction block. Therefore, both the choice of friction material should have good thermal

conductivity and can maintain a good frictional properties at high temperatures;

(2) The friction from metal and metal composition, mechanical deformation resistance is

small, the braking process will be worn brake blocks, there is no need to brake structure with

high surface roughness requirements;

(3) Taking into account the coal mine environment, friction by a hanging rail and friction

between blocks is not smooth, often attached to dust on the monorail braking zone guide is

easy to produce significant light scratches, the braking force is mainly composed of adhesive

friction frictional resistance and provide furrows; for yield limit - friction stability of the

furrow, the best selection of isotropic friction material of a certain thickness, in order to


improve stability.

After analysis, the choice of copper powder material design of the program, such as a matrix

material is copper, and add other elements, by sintering. When you add zinc, nickel and other

elements, the hardness and strength of the matrix material have been significantly improved

in order to add an element of tin material also has good toughness. The use of copper-based

powder metallurgy materials, braking process does not produce sparks, suitable for use at the

mine. In addition, thermal conductivity copper-based material is stronger than asbestos based

friction material, is conducive to frictional heat dispersed in time to help maintain

performance friction brake pads and improve braking reliability, stability, improve the life of

brake blocks.

2.5 Summary

First, this chapter summarizes the emergency brake hydraulic control system should have the

characteristics, analyzes the national standard requirements for brake control circuit should

satisfy for the requirements and characteristics analysis of the measures to be taken in the

design of the circuit, the final design of a hydraulic rope tow Monorail apply passive

emergency brake control loop, and a detailed description of the rail brake lock Brake run two

processes and implementation, summarizes the characteristics of the system. The circuit can

also be applied to batteries and diesel traction monorail monorail transport system as required

combination.

Then, sums up the type of friction material brake block coal mine locomotive, analyzes

the main factors monorail emergency braking friction, and analyzes the impact of positive

pressure on the friction; emergency braking Friction and Wear heat generating mechanism is

analyzed theoretically, and the frictional engagement, adhesive friction and variation of

friction furrows were analyzed, obtained braking force is mainly composed of monorail brake

friction and furrow adhesive friction provided, summarized the problem of brake block

material selection should be considered, and ultimately make the choice of copper powder

material as a friction block material.

Finally, with the help of the finite element analysis software ANSYS12.0 braking friction

and heat phenomena analysis, the temperature distribution contours brake block braking, the

maximum temperature 129.19C, meet the standard.


3 The Major Parts Design of The Monorail Emergency Braking

System_____________________________________________________

3.1 Determination of Braking Force_____________________________

Movement of the locomotive on overhead rail traffic is carried on the directed path (rail)

and in most cases in mines is a movement in the wheel-rail system.

In order to obtain the equation of motion of the train, it is necessary to take the following

location axes: the axis XX – horizontal, along the axis of the rail, the axis YY – the vertical,

upward, and ZZ horizontal axis perpendicular to the axis XX and directed to the right. Consider

the train as a material point located at the center of its gravity.

Figure 2 shows a diagram of the train and suspension forces acting on it. Point and – the

center of gravity and aerodynamic trains center of pressure, respectively. The origin is at O.

Figure 3.1 – Diagram of the train and suspension forces acting on it:

1 – rail; 2 – trailer; 3 – wagons

In general, when a train of mass m moving in a straight line on it are some of the forces:

train weight G = mg in the direction of the axis YY down, applied at the point ;

inertia in the direction of the axis XX at ;

traction or braking F in the direction of the axis XX, at the point О;

drag force on the mechanical loss in the direction of the axis XX at the point О;

force air resistance movement , which is the geometric sum of the and

having a component along the axis XX applied at the point .


Vertical and horizontal reaction force on the rail not shown in Figure 1. When driving on

a curve on a train centrifugal force , directed along the axis ZZ from the point of

application .

If the angle the way to the horizon ( > 0), the weight of the train is decomposed into two

components: axis XX and , perpendicular to the axis XX down.

Projecting all forces on the axis XX (direction), we obtain the basic equation of motion of

the train:

(3.1)

where – coefficient taking into account the inertia of the rotating masses of the rolling

stock;

s – the path of the train in the direction of the axis XX, m;

t – time, s;

sign "+" corresponds to the forces in the direction of the train.

To determine the components of equation 1, we consider the energy component processes

traction. To do this, we write the expression for mechanical work at a small gap in traction

mode:

(3.2)

where – mechanical work train locomotive with a warehouse, J;

– impedance of the movement of the train, N;

– incremental kinetic energy of the movement of the train, J.

For coasts, where the work forces of resistance is due to the decrease of the kinetic energy

(3.3)

In braking mode additional kinetic energy losses occur in the train braking devices:

(3.4)

where – the braking force of the train, N.

From (2), (3) and (4) can be rewritten for the general case of formula:

(3.5)

The value of the impedance includes primary and secondary. Additional includes

components which are dependent on: the construction of a moving, the state of the ambient

parameters false path. Thus, the impedance value can be written as:

(3.6)


The increase of the kinetic energy is only a target weight of the train, which does not

change during the trip, and the speed of its movement. The speed depends on the ratio of the

work of the tractive force, resistance, and braking. The operation of each component of the

equation (5) suffer changes that can be evaluated by means of correction coefficients, which are

defined as the ratio of the actual value of the work and the calculated values. Then equation (5)

can be written as:

(3.7)

where – coefficient change of traction, respectively, the resistance forces and

braking forces train.

Consider the component that takes into account the additional resistance force on the plan

and profile path:

(3.8)

where i – escarpment slope profile gauge, ‰.

Hence, with the formula 7 we find the escarpment slope section of the path length :

(3.9)

Resistance force and braking are defined by the relevant unit of force, depending on the

speed of:

(3.10)

(3.11)

where – specific resistance force of the locomotive and composition, respectively,

N/kN;

– specific braking force, N/kN;

P, Q – weight of the locomotive and storage, respectively, t.

Increase the kinetic energy of motion when the speed of to over a

distance determined by the formula:

(3.12)

Pulling force on the drive wheels can be found from the expression:

(3.13)

where – torque on the motor shaft, kNm;

– cardinality ratio of losses;


– gear ratio transmission traction device;

D – diameter of the drive wheels, m.

To move the locomotive at a constant velocity along a straight section of a journey to

overcome the resistance movement of the train. The maximum force on the drive wheels of the

towing device must be:

(3.14)

where m – mass of cargo, t;

– tare weight of the trailer trains, including the weight of containers, pallets and drawbars,

t;

g – acceleration of gravity, m/s2;

– angle monorail, hail;

M – mass of the locomotive, t;

W'– the coefficient of resistance to the motion of wheels trailer with a load of the train;

– coefficients of resistance to movement of running and the drive wheels of the

locomotive, respectively;

– number of pairs of driving wheels (drive modules);

P – total force pressing a pair of drive wheels, kN.

Addition to that defined by equation (14) the maximum force on the drive wheels do not

exceed the strength of coupling, which is considered to be equal:

(3.15)

where – coefficient of friction of the drive wheels with a monorail.

From (14) and (15) that the limit value of cargo can be found on the steady-state equation

(3.16)

Included in this equation coefficients , W', are empirical. We consider the

steady state because the inertia characteristic of the transient regime are negligible compared to

the forces of static

esistance, because of low velocities and railcars in mines.

The resulting equation (16) relates the three variables: the allowable load weight for

traction conditions of the drive wheels with a monorail, the angle of monorail track and the

contact pressure of the drive wheels.

Air resistance movement of the larger, higher speed and greater frontal area of the

composition. force of air resistance also depends on the geometrical forms of the


locomotive and trailer parts – streamlining. In the mining conditions the velocity of the air at

airing generation , which moves on the composition. Moreover receives both positive and

negative values, depending on the direction of movement relative to the direction of airflow.

Consequently, we can write an expression for determining the air resistance of the

movement:

(3.17)

where: S – frontal area, m2;

v – speed of movement of the rolling stock, m/s;

k – coefficient of aerodynamics, Ns2/m4;

– air ventilation rate of output.

The calculated braking force...

Principle of the braking process

Popular at home and abroad by monorail transport equipment described above braking

structure and characteristics of the work process analysis, the design uses three hydraulic

brake lever embedded structure. Three rod hydraulic emergency braking is achieved by

external forces, the main course is a spring accumulator, when the brake cylinder oil

unloading, through the spring pressure brake block pressed onto the track of the web, a

positive pressure, the braking force provided by the frictional force between the brake blocks

and the rail, thus achieving braking. By sliding friction in physics formula, you can calculate

the size of friction of 2.10 schematic diagram of a brake works

Figure 3.2 The sketch diagram of braking principle

The formula can be based on the physics of friction

Nbrake FnF (3.18)

therefore，

F — The total friction brake blocks and hanging rail between；

— The coefficient of friction between the brake blocks and rail；

NF — Positive pressure between the brake blocks and rail；

N — The number of friction blocks。

From equation (3.18) can be seen, the braking force coefficient of friction between the brake

blocks and rail by the positive pressure and the influence of brake block number, the greater

the friction coefficient, the higher the positive pressure, the more the number of brake blocks ,

the greater the braking force. The coefficient of friction due to differ gate number of blocks to


be determined by the choice of lining material according to the size of the traction system.

Under normal circumstances, the greater the positive pressure, the braking force under the

same conditions to obtain greater, but the pressure is bringing a lot of problems over the

General Assembly. Track withstand increased positive pressure, the spring means to store

more energy, the hydraulic cylinder working pressure, which brings the oil pressure increases

due to the pipeline to increase the amount of the leakage problem. In addition, if the positive

pressure, friction pad wear serious, affecting the lining life. In selecting a braking device shall

be designed to meet the mine of high coefficient of friction materials for use in selecting a

braking device shall be designed to meet the high coefficient of friction of the material

conditions of the mine, the rational design of positive pressure, determine a reasonable ratio

and arm the number of friction blocks.

The calculated braking force

According to coal industry standard/T886-2000: coal mine rope pulling monorail

standard, locomotive traction generally 45kN or less, the maximum towing speed of 3.5m / s

or less, climbing angle at 25 ° below the horizontal track turning radius ≥6m, vertical turning

radius ≥10m. Table 2.1 of Shijiazhuang Coal Mining Machinery Co., Ltd production of rope

pulling Monorail and the Shandong Sinsa monorail transportation equipment Limited

production of DX40 battery traction Monorail main parameters compared. As can be seen

from Table 2.1, these two types of monorail traction, the same model used in orbit, differ only

in climbing angle and running speed, the program according to the monorail traction to 40kN,

pulling speed of 1.6m / s design, combined with the standard braking force is the sum of not

less than 1.5 times its rated traction requirements, the braking force determined that this

program is designed to 60kN.

Table 2.1 rope tow monorail monorail traction battery with DX40 main parameters

comparison table Table2.1 The main parameters comparison between rope traction monorail

and DX40 battery traction monorail

Table 2.1 The main parameters comparison between rope traction monorail and DX40 battery

traction monorail

Type SDY Monorail traction rope DX40 Traction batteries

Monorail

Traction/kN 40 40

Speedm/s 0-2 1.6

Maximum climbing angle ° 25 16

Track Type I140E I140E


Figure 3.3 The sketch diagram of brake mechanism

The braking device with three hydraulic brake rod structure, Scharf three hydraulic brake

rod structure similar structure diagram as shown in 2.11. This means the total braking force F

jointly by the four structures, the same material brake block, brake clamping force is designed

to arm ratio of 1: 3, the brake block braking force needs to be provided for each of 15kN, that

is, each the friction between the brake blocks and the track is 15kN. Figure 2.13 is a

simplified schematic of the brake caliper, the friction coefficient between the selection and

rail friction material of 0.25, according to the formula (2.1) can be positive pressure is 60kN,

a pressure spring provided when needed can be drawn from the principle of the lever brake to

20kN .

Figure 3.4 The sketch diagram of simplified brake clamp


3.2 The Selection of The Brake Spring

Figure 3.5 Standard Spring

The basic compression rate and wire stress for a compression For these reasons, refinements

in large spring design should spring can be estimated with the following: be left to the

experienced spring designer.

Where:

D= Mean diameter, (O.D. - d) inches

d= Wire diameter, inches

G= Modulus (spring steel = 11.5x106,

stainless = 10x106), p.s.i.

K= Stress correction factor (see plot)

N= Number of total coils

n= Number of active coils (see table)

R= Spring rate, pounds per inch (lbs./in.)

S= Wire stress, psi

Note: One should not employ the curvature (k) correction P= Applied load,

pounds

stress in an expression solving for deflection. Use the p= Pitch, distance

between centerlines uncorrected stress only or errors will occur. The

uncorrected of wires of adjoining coils stress can be used for static applications.

Large wire and bar stock sizes also require an empirically- Δ= Deflection,

inches

derived reduction in the standard rate calculation of up to 9%. π= 3.14

Spring Selection and Calculation

When using the spring, mainly used in clamping force, vibration and energy storage, etc.,

generally composed of carbon spring steel, stainless spring steel, copper alloy, nickel alloy,

alloy spring steel and other materials, according to the function and shape can be divided into


tension springs, compression springs, scroll springs and torsion springs.

Brake pressure of this program is to provide emergency brake by spring pressure, spring reflect

its storage effect, so the need for springs Selection and sizing. Depending on design

requirements, the program uses helical compression spring, spring material selection rolled

spring steel [30], its main parameters are calculated as follows:

Original Condition: suffered because the spring load changes, but taking into account the effect

of number is less than 104, it is Class III loads. When the brake device is holding rail brake

state, the spring has a minimum working load P1, its size for 30kN; when the brake device is in

the disengaged state of the spring to resist the pressure of the hydraulic cylinder, when spring

has a maximum working load P2 this program value of 40kN.

By mapping can get loose brake compression spring length 385.95L 初始mm；The

new liner braking spring length mm31.484制动L ；Wear and tear 4mmAfter braking

spring length mm31.500制动L ，

(a)Loose braking mode (b)Braking mode (c)Braking mode after abrasion

Figure 3.6 Three braking mode

According to "Mechanical Design Manual", when the spring material diameter greater

than 8mm, use tight ends and polished without the support ring 0.75 ring spring; because the

spring under load is large, so I chose high temperature, high-strength hot-rolled 50CrMnA

60CrMnA as spring steel or spring material [31]。

First calculate the spring stiffness：

2 1 30000 2000087.44N /

500.31 385.95

P PP mm

L L

制动初始

(3.2)

Working Load Limit: You can get through the tables refer to the "Mechanical Design Manual"

P1>Pa → P1=40kN (3.3)

Spring material diameter d and spring diameter D and the relevant parameters

Table 2.2 The main parameters of the spring

d D Pj fj dP

30 100 34788 25.69 1354


Effective number of turns：

135415.48

87.44

dPn

P

(3.4)

11-2-10，Effective number of turns n,taken as16

Total number of turns：

1 1.5 17.5n n (3.5)

Spring stiffness：

135484.625 /

16

dPP N mm

n

(3.6)

Limit the amount of deformation under load work：

16 25.69 411.04j iF nf mm (3.7)

Pitch：

411.0430 55.69

16

jFt d mm

n (3.8)

Spring free height：

mmH 9500

Spring diameter：

mmdDD 130301002 (3.9)

Spring inner diameter：

mmdDD 70301001 (3.10)

Minimum load height when：

11 0

20000950 721.27

87.44

PH H mm

P

(3.11)

Maximum load height：

22 0

30000950 606.9

87.44

PH H mm

P

(3.12)

The actual working stroke：

1 114.36nh H H mm (3.13)

High aspect ratio：

0 9505.27 5.3

180

Hb

D (3.14)

So no need to carry out spring stability computations。


3.3 Design of Brake Hydraulic Cylinder

Hydraulic Cylinder Parts

Figure 3.7 Standard Hydraulic Actuator and its principle

Hydraulic cylinders consist of a smooth bore round tubular cylinder, a freely moving piston

with several polymer seals, a highly polished round piston rod and a rod support bearing

along with several tight-fitting seals to seal the sliding rod where it exits the cylinder. The top

of the cylinder as well as the end of the piston rod have clevis fittings which allow angular

movement of the device the cylinder is attached to. Each end of the cylinder has a threaded or

compression fitting opening where the hydraulic pressure tubes are connected from the

cylinder control valve.

Cylinder Operation

When the control valve handle is moved toward the extend cylinder position, hydraulic fluid

under high pressure--usually 500 lbs. to thousands of lbs. per square inch is allowed to flow

from the hydraulic pump to the piston side of the cylinder, while the oil under the piston by

the rod side of the cylinder is allowed to flow from the cylinder and back to the reservoir. If

the handle is pushed to the retract position, the pressurized oil is sent to the rod side of the

cylinder, retracting the cylinder and pushing the oil on top of the piston and back to the

reservoir.


System Description

A typical system employing hydraulic cylinders to accomplish work requiring large

forces--such as a hydraulic power excavator shovel used to perform construction

excavation--consists of the engine-driven hydraulic pump, oil reservoir, cooling and filtering,

operator controls, tubing and the hydraulic cylinders.

Hydraulic Gain

This provides a much higher output force from the cylinder than the force applied by the

motor, albeit at a proportionately lower speed. In the case of hydraulic jacks, rams and presses,

this is exactly the goal of using hydraulic cylinders--tons of force available at slow to

moderate speed of inches per minute.

Hydraulic force - area formulas and calculator

Figure 3.8 Symbolic Diagram of an Actuator

The force produced by a double acting hydraulic piston on the rod side can be expressed as

F1 = (π (d22 - d1

2) / 4) P1 (3.1)

where

F1 = rod pull force (lb, N)

d1 = rod diameter (in, m)

d2 = piston diameter (in, m)

P1 = pressure in the cylinder (rod side) (lff/in2 (psi), N/m2 (Pa))

The force produced opposite the rod can be expressed as

F2 = (π d22 / 4) P2 (3.2)

where

F2 = rod push force (lb, N)

P2 = pressure in the cylinder (opposite rod) (lff/in2 (psi), N/m2 (Pa))


Push Diagram

Rod pushing force for hydraulic cylinders are indicated below:

Figure 3.9 Graphically showing Rod pushing force for hydraulic cylinders

1 psi (lb/in2) = 144 psf (lbf/ft2) = 6,894.8 Pa (N/m2) = 6.895x10-3 N/mm2 = 6.895x10-2 bar

1 N/m2 = 1 Pa = 1.4504x10-4 lb/in2 = 1x10-5 bar = 4.03x10-3 in water = 0.336x10-3 ft water =

0.1024 mm water = 0.295x10-3 in mercury = 7.55x10-3mm mercury = 0.1024 kg/m2 =

0.993x10-5 atm

1 lbf (Pound force) = 4.44822 N = 0.4536 kp

1 N (Newton) = 0.1020 kp = 7.233 pdl = 7.233/32.174 lbf = 0.2248 lbf = 1 (kg m)/s2 = 105 dyne

= 1/9.80665 kgf

1 in (inch) = 25.4 mm

1 m (meter) = 39.37 in = 100 cm = 1000 mm

3.4 The Selection and Design of Other Important Parts

Structure

The design of the emergency braking device of the device consists of brake arm, trays,

storage spring, frame body, rod, friction block assembly, centrifugal release device, fork

switches and other parts, the structure and layout is shown in Figure 2.14 FIG.

The device consists of four symmetrically arranged on the scroll wheel support rails

distance between the two scroll-wheel is 660mm. Has two sets of three-rod hydraulic brake

mechanism, in order to improve stability, the use of frame body between two risers


connecting the two lateral panels; vertical plate welded frame body around the guide tube

brake, and the brake lever maximum gap 1mm, to reduce the stress on the rod between the

sleeve and the frame body during braking; the right side plate welded centrifugal rotating

lever release device support. Each braking device comprising two brake arms, and together

form the brake lever and strut three-link mechanism. 1mm gap left between the supporting

plate and rib plate bracket to facilitate installation. By mapping can be obtained when the

brake device consists of brake release state to the braking state, the brake arm rotational angle

of 8 °, rod horizontal displacement of 17mm.

Type hanging rail Introduction

Figure 3.10 Standard dimension of a Hang Rail.

Monorail section of I140E The connection of joist steel monorail

Figure 3.11 Shows the connection between to monorails


The trigger switch design

Centrifugal releaser for speeding is controlled by the slide shaft extending trigger the

appropriate agencies in order to achieve control of the hydraulic control system, the final

completion of the emergency braking action [35]. The program consists of a sliding shaft

extension, the two blade switches and hydraulic relief valve trigger execution speed governor

mining results. When the rotation axis angular velocity is increasing, and slide the shaft

extension, along with the release of the rotating centrifugal, centrifugal releaser impact left a

small gap of a trigger switch blade. Switch blades and the release valve with another, so that

the release valve is spring in a compressed state without conducting. When the slide shaft hit

the trigger switch, the switch is fixed around its own axis, release the spring to extend valve,

turn to the conducting state by the closed state, so that the hydraulic circuit unloading, brake

calipers at the spring pressure brake block pressure to the rail, complete brake.

Two blade trigger control trigger switch is an important part of the process, its design

should not only consider the role of the slide shaft impact should be considered release valve

is fully closed spring pressure. Two trigger switch blade structure shown in figure.

Figure 3.12 The structure of two blades trigger switch

The trigger switch in the knock-on effect around its axis of rotation, the friction and impact

forces on the shaft torque demand, there are: 0 oM

0force springforce percussice bFaF (3.1)

Where：a To the point of impact to O Point distance；b To release valve spring blade

contact point to O From the point of； The coefficient of friction at the contact；springF

Positive pressure relief valve spring given switch blades。

springforce percussiceF

a

bF (3.2)

Slide the shaft of the switch leaves the size of the force and the distance from the impact

point of the O point of relief valve spring pressure, friction coefficient, the blade force is

related to the release valve selection and blade length are interrelated. When the release valve

is determined to be appropriate to increase the length of the blade, the point of impact and

increase the distance between the center of the shaft to reduce the impact force, to reduce the

sliding projecting shaft impact deformation; when the switch blade length is determined,


should be a reasonable adjustment pressure relief valve spring, try to use a smaller opening

release valve action to meet the impact force to reduce sliding shaft deformation. Two blade

trigger switch by rotating shaft is fixed to the brake bracket body, between the centrifugal

release should be left with the very small gap, but requires arranged in the slide shaft end can

touch location area extends, as shown below,for the trigger switch schematic arrangement。

Figure 3.13 The lay-out of a trigger switch.

Emergency brake hydraulic control circuit design

Emergency brake hydraulic pressure control loop characteristics

This topic is designed monorail rope pulling the emergency brake system uses a three-friction

brake lever recessed structure, this kind of mechanism is implemented by a hydraulic cylinder

and with a compression spring. Braking, rapid unloading hydraulic cylinder, under pressure in

the spring brake pressure to the rail webs, the braking force is provided by friction; normal

operation, the hydraulic cylinder rod chamber is pressurized, so that the compression spring to

store energy, until it is completely loose brake status. In both processes, the outer cylinder

bearing load exerted by the spring only, and is changing even while requiring braking should

fast unloading, to ensure the stability of the system pressure Brake runtime.

Overall, the emergency brake hydraulic pressure control system has the following

characteristics;

(1) single action execution units: the process of braking and brake release hydraulic cylinder

that is pressurized and unloading process, the implementation of parts of the brake cylinder as

the only spring mating;

(2) should have a fast response time unloading: As mine safety rules in emergency braking

lost motion time there are strict requirements, it is necessary to ensure fast response.

(3) hydraulic piping should be as short as possible: a short hydraulic lines can reduce oil

leakage, help maintain the stability of the system pressure, the process of moving the

locomotive to avoid frequent automatic emergency braking condition affecting the normal

production;

(4) shall satisfy both the manual brake also automatically braking requirements: manual

operation is related to manual control valve to achieve complete braking system during

braking, automatic hold some kind of rail brake applications requiring speed limiting device,

when speeding occurs when the switch can automatically trigger the hydraulic cylinder timely


unloading and brake.

(5) to load changes require Low: positive pressure hydraulic brake system must meet the end

state requirements needed to keep the system pressure stable Brake, mainly on the early end

of the two states that require high.

Emergency brake hydraulic control circuit

According to the "Coal Mine Safety Regulations" requirement, and hydraulic system design

issues that need attention, for monorail locomotive traction rope emergency brake hydraulic

circuit design, shown in Figure 3.1. The system automatically hold both rail brake can over

speed, it can also be achieved artificially emergency brake to work or when. The design of the

hydraulic system is mainly composed of hand pumps, relief valves, bleed valves, check valves,

hydraulic cylinders, release valve, centrifugal release, pressure gauges and other components.

Figure 3.14 Components of a Hydraulic system

1) Brake during operation. Pulling the handle 10, the pressure limiting valve 8 spool move on,

cut off the oil; turning the manual pump 1, the hydraulic oil into the brake cylinder 6 retracts

the piston rod to the cylinder, in order to achieve Brake; gauge pressure rises to set up After

setting, release handle 10, a hand pump is stopped; hydraulic control valve body 8 due to the

action in the open state, release valve 5 due to the ends of the pressure balance in the off state,

then the monorail normal operation.

If the oil pressure does not stop when the system reaches the set value the pump and

release the handle10, or due to system leaks the working fluid pressure drops below the set

value, the spool valve 8 is turned down and the relief tank, which When the discharge valve5

to the left and transposition, the hydraulic cylinder 6 within rapidly released, and ultimately

hold the rail stop. Only Repeat the above procedures to lose brake operation. Action pressure

limiting valve8 is to maintain a certain hydraulic systems, to ensure that only monorail

locomotive brake release state in the whole operation, to avoid the resistance due to the low

oil pressure, brake release state run in the second half due to the increase and brake pad wear

problems2 relief role is to avoid high pressure hand pump pressure system, ensure the system

work.


2) The brake application during braking. Automatic brake application during braking

speeding through centrifugal release is achieved. Take the line speed locomotive wheel speed

runtime into rotational shaft speed centrifugal discharge device, driven centrifugal releaser

rotate. When the locomotive normal driving, the slide does not extend or extend the length of

the shaft is small, you cannot touch the trigger switch; when the locomotive speeding, sliding

shaft extends longer than the set value, hit the trigger, so that the release valve 7 action

change to, release valve 5 due to the pressure imbalance and the action ends, the brake

cylinder is turned on the fuel tank, to achieve the emergency brake under spring pressure.

This system has the following characteristics: a small hydraulic components (1), a

shorter pipeline, the system is simple, reducing the hydraulic oil leakage and maintenance of

hydraulic components, improve the safety of the hydraulic system; (2) guarantee You can run

the locomotive at full brake release, avoiding the low oil pressure, running at half unbraking

state brought too much resistance and brake pad wear serious issues; (3) the use of a hand

pump instead of a hydraulic gear pump supply control loop, ie no motor driven, small brakes

overall size, small footprint; do not use the solenoid valve, the system is still available in case

of power failure; (4) according to the size of the monorail traction, it is reasonable choose the

number of braking device; (5) the system can be applied to the emergency brake battery and

diesel monorails monorails control loop, without the need for much improvement; (6) brake

system uses voltage brake, provide positive pressure, given the rapid, can achieve rapid

braking action requested by the spring pressure of the spring; (7) has a release valve and

centrifugal releaser, when a speeding by a broken rope caused by such factors, the centrifugal

releaser transposition can release valve, hydraulic cylinder unloading, enabling automatic

hold rail brake.

3.5 Summary

This chapter focuses on the working principle and characteristics of brakes Monorail, all the

major domestic manufacturers were used in the analysis, summarized the national standard

monorail emergency brake requirements, studied Scharf Group Company braking device

design and testing requirements, and ultimately proposed using three rod hydraulic brake

embedded structure design of the structure of the present. In addition, analysis of the physical

principles during braking and braking force influencing factors, and in accordance with the

adopted structure to SDY rope pulling monorail for the study, we designed a passive

emergency stop device structure. In the braking device design process, mainly to complete the

selection and calculation, brake and other content structure and layout of the spring. Finally,

the release of the study centrifugal structure, working principle, the establishment of a

simplified mechanical model, designed a two blade trigger fork structure


4.3D Solid Modeling and Simulation

4.1 3D Solid Modeling

The Design base was to design a brake caliper that is small and yet able to space enough

clearance for the spring and hydraulic actuator to move freely.

figure 4.1, Shows the design based drawing.

Once the minimum pressure for the hydraulic actuator and the power spring were determined.

Using reference, a standard hydraulic actuator and spring was selected of the needed Force, yet in

smaller size. Once these standard part were in place, the design of the caliper was made as shown in

figure 4.2 (below)

figure4.2, Dimensions of design


Figure 4.3, shows the 3D drawing of the Brake-caliper as if it appearance in the system. This

3D AutoCAD drawing was to conform that the brake caliper is of good dimension and

spacing, and thereby can be applied.

figure4.3, 3D AutoCAD drawing of appearance and arrangement of system

figure 4.4, shows the 3D model of the brake-caliper, drowning using Work-bench. This model is using

in the Ansys stimulation to determine whether the caliper is able to withstand the force it is exposed to,

both while the brake is on and while it is release.

figure4.4, 3D Model, using Work-bench


4.2Simulation of Braking Performance

Brake calipers-static analysis

To judge the reliability of structural design, using Solid works Simulation module of this

programmed complete the brake the main structure of static analysis. UG NX 6.0will be used

for the simplified mock-up re-deposited to the Para solid format file, and then imported into

Solid works simulation analysis. Added links to parts and materials properties, define, define a

component interface group, adding fixtures, application of external loads, meshing, calculation

and analysis of sequence and finally to complete statics analysis of the process model built by

[60]. Because the model loads, materials, structure with symmetry, so you can one-fourth the

structure of models by the symmetry and pin connector instead of the real pin can be used to

reduce the number of contacts, reduce the number of units and number of degrees of freedom,

and ultimately increase solution speed, solving the model as shown in Figure 4.8. Define brake

blocks and Rails, pads and trolley shafts with contact sets, set parts contact types for

non-penetrating type, and establish symmetric constraints, fixed rack and Rails. Alone is the

main component of the braking end state analysis of stress and strain, may be at the bottom of

the brake arm applying a constant load, replaced by the size of horizontal force of 20kN spring

pressure. When the mesh, select the grid based on curvature, which can change life into the

grid, good for small features Department in the geometry to get accurate results. To run the

examples built by analysis model of stress, strain, and displacement diagrams can be obtained,

respectively, as shown in Figure 4.9, 4.10 and 4.11. Use maximum von Misesstress as yield

failure criteria by defining the graphic safe area safety and non-safety areas graphically, as

shown in figure.

In finite element analysis, brake levers, brake arm, frame selection of carbon structural

steel Q235, its yield strength is 240Mpa, friction plates in brass, its yield strength of 239Mpa.

Through stress diagrams can be seen, this maximum stress values of 163.9MPa, below the

part material yield strength due to stress concentration, maximum stress on the brake arm

corner appear, considering the area is small and the stress is greater than the yield stress, you

can ignore its impact on the structure. By the strain diagram see, now the biggest stress

maximum strain areas, the maximum value is 0.67mm. Displacement diagram shows that the

maximum displacement occurs in the liquid tray springs and brake arm joints, maximum

displacement of 1.6mm, compared to the spring trip, its value is unlikely. Figure 4.12 is based

on the maximum von Mises stress of yield failure criteria of the security area map, red for

non-security zones, blue for the security zones, due to the structure of maximum stress does

not exceed the yield strength of the material, the regional shows are in blue, the biggest stress

region at a minimum safety factor, but still guarantee safety. Use pin connector replaces the

real pin, so you need to determine the PIN shearing stress situations, using Simulation

detection capability will get the PIN in the shear size, as shown in table 4.1. Can be obtained

from the table, the pin of the shear force shall not exceed the allowable shear stress, you can

think of each pin design. Conclusion can be summarized, the programme designed structure

of brake is reasonable.


Figure 4.5Total Deformation(brake on);

Figure 4.6Elastic Strain(brake on);

Figure 4.7Stress(brake on);


Figure 4.8Total Deformation(brake released);

Figure 4.9Elastic Strain(brake released);

Figure 4.10Stress(brake released);


Emergency braking friction and heat analysis

Emergency braking process is monorail system kinetic energy into heat energy in the process,

are hot - structure interaction, constant friction brake during braking, brake friction work done

only relevant braking distances, without affected initial velocity, and reduces the amount of

kinetic energy equal to the value of the system. When the vehicle speeds up m/s08.2 At the

beginning of the brake, setting the total weight of the locomotive monorail 15t，The brake

deceleration of 2m/s4 ，Braking distance 0.54m。

In ANSYS, friction between two objects generated total heat flow rate can be cal

culated as follows:

q FHTG v （4.1）

where，FHTG Friction heat energy conversion factor（The default is 1）； Equivalent

friction stress；v The relative speed of the two objects slide。

The contact surface of the heat flow rate：

cq FWGT FHTG v

（4.2）

therefore， cq Heat flow rate obtained by the contact surface；FWGT The target surface

and the contact surface heat distribution weighting factor（The default is 0.5）

Target surface heat flow rate：

(1 )cq FWGT FHTG v

（4.3）

therefore， cq Heat flow rates obtained by the target surface。

In this paper, the direct coupling solution, with the completion of the thermal coupling

analysis ANSYS12.0 emergency braking process, has been the distribution of temperature

field of brake block braking, the highest temperature obtained when the emergency brake

brake blocks.

(1) define the element types

Because it is a direct coupling solution is solved, so choose Coupled, Scalar Brick 5 field

three-dimensional six-sided eight-node coupled field analysis unit.

(2) define the material properties

Analysis, use copper material brake block, brake blocks and rail material parameters are

shown in the table:

Table 4.1 The material parameters of brake lump and rail

Materi

al

Temperature

/oC

Elastic

Modulus/

GPa

Density/(kg/

m3)

Heat transfer

coefficient/(

W/m oC)

Specific

heat

capacity/(J

/kg oC)

Thermal

expansi

on

coeffici

ent /(1/

oC)

Poisso

n's

ratio


Brake

block 20 103 8900 383 390 1.75e-5 0.3

Guide 20 206 7800 66.6 460 1.06e-5 0.3

（3）Establish geometric model

Sliding friction braking process is equivalent to between two sliders, where the structure is

simple, using direct modeling in ANSYS way to build a geometric model, shown below.

Figure 4.11 Geometric model

(4) mesh

Since the braking time is very short, but relatively rail brake rail longer braking heat focused

on the brake blocks, as well as reducing the amount of calculation, so as to improve the

accuracy of the brake block using finer mesh than rail . Brake control block mesh size of

1mm, rail control in 3mm.

(5) establish contact pairs

Brake blocks and rails relative motion, it is necessary to establish contacts between the two

pairs, and set the friction coefficient is 0.25.

(6) adding pressure load

In this analysis that the initial moments of the brake pressure will reach a maximum 16.5MPa,

and there is no change in the braking process, it does not consider the effect of temperature on

the friction factor, adding a constant surface pressure on the brake block load 16.5MPa .

(7) add constraints

Setting the external environment for the initial 30 oC, and the lower surface of the fixed rail

web, constraint displacement brake block Y direction and Z direction.

(8) add displacement load

Since it is considered as a constant friction, heat and generate only the braking distance, and

therefore can be added to the right end surface of the gate block 0.54m displacement load.


(9) set solution options

Solving option to transient analysis Transient large displacements, solving step number is set

to 10 steps, each step of recording the results.

(10) Analysis of the Solution

It can be obtained by solving the brake blocks and the rail temperature field distribution, the

contact surface heat flux profile, contact stress distribution, as shown in Figure 3.13, Figure

3.14, respectively, as shown in Figure 3.15. The figure shows that the maximum temperature

129.19 oC, standard MT / T1064-2008 required brake surface temperature no higher than 150 oC , and therefore the brake pressure is reasonable.

Figure 4.12 Temperature image of the brake lump and the rail

Figure 4.13 Thermal flux of the contact surface Figure 4.14 Contact stress envelope


4.3 Summary

This chapter established by means of UG NX 6.0 brake main structure of three dimensional

solid model using dynamic simulation software ADAMS on the braking process kinematics

simulation, Rod and sleeve-gap variation is obtained, and the brake blocks with hanging Rails

web contacts are change, while the wave phenomena is analyzed, improved the surface the

brake block is completed. By Solid Works Simulation completed the final braking brake static

mechanical analysis of main structure, design of structures is reasonable. Using Pro/e

complete a simplified model of centrifugal releaser, combined with dynamic simulation

software ADAMS completed kinematic simulation, spring is obtained the initial amount of

compression and the speed of the rotating shaft sliding out of the shaft out of the displacement

curve through the analysis of simulation results to determine the layout area of the trigger

switch.


5 Conclusions and Prospects

5.1 Conclusions

For nearly two years, in the face of coal stockpiles rise, benefits decline, falling prices,

competitive issues, the pursuit of effective, many existing small and medium coal mines began

to reform the traditional way of underground auxiliary haulage, new large mines are becoming

larger, in the direction of increasing degree of automation. Mine monorail locomotive, a type of

auxiliary conveying equipment with high efficiency in mine production is widely used, in order

to meet the needs of modern mine construction, improve large monorail transport technology,

transport capacity has become an important way to improve productivity.

The subject of the new monorail transport equipment with high efficiency in application of

underground auxiliary haulage system analysis and development, at the same time in order to

meet the requirement of high production and high efficiency mine construction and production

to further improve reliability and safety of the monorail locomotive, researched and designed a

mine steel rope haulage monorail locomotive with passive emergency brake. The main

conclusions of this research are as follows:

(1) through on both at home and abroad common monorail hanging brake device of structure

composition, and work principle and the features of analysis, again combines GB in the related

mine with auxiliary transport vehicles emergency brake device of requirements, especially for

monorail hanging locomotive of requirements, reference Germany, Jakob Scharf, company on

monorail hanging brake device of enterprise specification, design has a rope traction monorail

hanging with three Rod embedded type no source emergency brake device.

(2) the existing monorail hoist hydraulic circuit is analyzed through extensive access to the

relevant information, summed up the emergency braking characteristic of hydraulic control

circuit and design should pay attention to the problem, a passive emergency stop device is

designed to use the hydraulic circuit.

(3) summary has common brake friction material, on emergency brake process in the friction

size of effects factors, and friction hot produced mechanism and the brake friction tablets of

wear mechanism for has analysis research, and according to analysis results determines has this

programmed by with of brake friction material, while on brake friction born hot phenomenon

for has limited Yuan analysis, get has gate block and guide temperature field distribution figure,

determines brake Shi Supreme temperature meet standard of requirements.

(4) using software UG NX 6.0 completed the emergency stop device the main structure of

three-dimension solid modeling, and Solid works Simulation modules for emergency stop

device in static analysis of the main structure, and finalize the designs reasonable.

(5) with virtual prototype simulation analysis software ADAMS on emergency brake Shi lever

and machine frame sleeve between of clearance changes law and the gate block and guide

abdominal Board between of contact process for has analysis research, obtained brake process

in the lever and sleeve between will produced is small of interference, proposed gate block and

guide of contact process exists fluctuations, and fluctuations range gradually reduced,

eventually in stable state. According to the simulation results, contacts in order to reduce the

volatility and increasing braking stability and service life of brake blocks, thickening of the

surface of the brake blocks was improved.


(6) the establishment of simplified mechanical model of centrifugal releaser, and modeling of

virtual Assembly technology to complete the system, ADAMS simulation analysis software for

the initial amount of compression and the speed and the diameter of springs on the sliding shaft

extending effect arrangement obtained under specific environmental trigger switch theory.

5.2 Prospects

For coal mining monorail locomotive with passive emergency brake a braking mechanism

analysis, structural design, design and simulation analysis of hydraulic system, but due to the

limited time conditions and personal skills, project there are a lot of issues that need further

study and improvement, mainly include the following aspects:

(1) this project used for emergency braking mechanism design are the commonly used

three-lever hydraulic insert-type friction brake mechanism, braking lever for Planar kinematic

linear motion instead of a specific direction, the Guide sleeve and the need for clearance

between lever and this leads to fluctuate brake block contact with the rail, not conducive to

the stability of braking. Therefore needed on this basis to improve the structure, or a new type

of both sides can achieve synchronous vertical loading of the brake mechanism.

(2) thedown hole environment combined with the actual analysis of the emergency

braking brake blocks braking factors influencing wear mechanism of power source, brakes,

brake blocks, guiding the choice of brake material, we should design a conducive to

dissipation of surface structure of friction properties of brake blocks, and tested.

(3) draw the shoes and Rails through motion simulation is a process of fading fluctuation

between, this article only on the qualitative analysis of the fluctuation process, we should

study on fluctuation phenomenon influence on the service life of brake friction and brake

blocks.

(4) no more on oil brake cylinder when discharging time calculation of detection,

emergency brake valves of the hydraulic circuit to elements not selection, you must next

election conducted on various components and hydraulic oil tank discharge measured by

using testing time.


References

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2. Cardno_ Shaping the Future/ Mining solutions customized to your challenges

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Acknowledgement

Foremost, I would like to express my sincere gratitude to my advisor Prof. ZhuXuLi for the

continuous support for my study and research, for his patience, motivation, enthusiasm, and

immense knowledge. His guidance helped me in all the time of research and writing of this

thesis. I could not have imagined having a better advisor and mentor for my project study.

I thank my fellow project-partner: Navidu Heshan, Dilshan Bopage, Sandun Tharaka for the

stimulating discussions, for the sleepless nights we were working together before deadlines,

and for all the fun we have had in the last four years. Also I thank my Chinese friends in

Shandong University: Qi Hui, Gong Xu Bo and others who helped me in my thesis.

Many people, especially my classmates and team members itself, have made valuable

comment suggestions on this proposal which gave us an inspiration to improve our

assignment. We thank all the people for their help directly and indirectly to complete my

assignment.

Documents

Eshan Senanayake- Thesis 2011