NEI Technical Case

Competition

Please paste your photo

(would prefer a smiling one)

Raju Chaudhary

ROLLING CONTACT

BEARINGS & FUEL EFFICIENCY

Presentation Overview

• Introduction• Contribution of Bearing to overall vehicle fuel efficiency• Significance• Selection For Fuel Efficient Bearings at Normal Conditions• Suggestion For Fuel Efficient Bearings• Total Friction Torque Calculation Formula • Final Result • References

IntroductionRolling bearings play a significant role in energy conservation.

The significant advantage of rolling contact bearings over a sliding contact bearings that it has a low starting friction.

Due to this low friction offered by the rolling contact bearings, these are called antifriction bearings.

Fuel Efficiency in Global environment

The objective of fuel efficiency is to development of a cleaner, more efficient vehicle strategy, policy package, and adopt best practices on fuel economy improvement so as to reduce the average fuel consumption.

Improves Fuel Economy and National Economy

Protects the Environment

Conserves Resources

Significance

Illustration by examplesContribution of Bearing to overall vehicle fuel efficiency

Energy Conservation by Rolling

Figure 1: Comparison of energy consumption for vehicles with and without rolling bearings.

Contribution of Rolling Contact for Roller Tappets and Rocker Arms

Figure 2: Design of rocker arms

Conventional rocker arm (Sliding type) Rocker arm with needle bearings

Contribution of low Friction Tapered roller Bearings

Tapered roller bearings used in automotive power trains have rather high frictional resistance compared to other rolling bearings.

The bearing running torque has been reduced 20 to 50% by reducing friction coefficient between the large head of the roller and the rib surface, and by applying crowning the outer ring race way.

Contribution of Automotive Transmission Rolling Bearings

Needle roller bearings are used in transmission gear shafts .Frictional torque has been reduced by about one-tenth with increased machine and fuel efficiency resulting in greater energy conservation.

Figure 4: Application of rolling bearings in sedan transmission

Selection For Fuel Efficient Bearings at Normal Conditions

Bearing Location: Gearbox ShaftAnalytically Test were Conducted For Three Bearings

Deep Groove Ball Bearings Double Row Angular Contact BearingsTaper Roller BearingsConstant Parameter: Fa=3250N, Fr=4000N, n=1750 RPM, Shaft Orientation- Horizontal, Lubricant Viscosity- (120 – 12 ) mm²/s

This is Suggested By SKF

Further low Friction Tapered roller Bearings can Be Improved Barest Minimal Level

Figure 6: Running torque of low-torque tapered roller bearings

Bearing bore: ø30, ø50 mm Axial load: 3.92 kNLubricant viscosity: 23.3 mm ²/s

Conventional bearings

Improved bearing I

Improved bearing II

Runn

ing

torq

ue

Nm

·

Speed (rpm)

Suggestion For Fuel Efficient Bearingsby Optimized Design

Figure 5:Taper roller bearings

Further Improvement

Turbo Technologies

Improving the Performance of Rolling Element Bearings with Nanocomposite Tribological Coatings.

Experimental and Analytical Methods for Assessing Bearing Performance Under Debris Contaminated Lubrication Conditions.

Total Friction Torque Calculation Formula Applied

Total Friction TorqueM=MM=Mll+M+Mvv+M+Mff

Total Friction Loss (H)=0.001M.Total Friction Loss (H)=0.001M.ωωn: Rotation Speedn: Rotation SpeedMMll : Bearing Friction Torque due to Load : Bearing Friction Torque due to Load

MMvv: Bearing Friction Torque due to Lubrication: Bearing Friction Torque due to Lubrication

MMff:Bearing Friction Torque due to Roller end Flange Load:Bearing Friction Torque due to Roller end Flange Load

Ball Bearings Friction Torque

Torque Due to Applied Load: Ml = flFβdm

Fl=z(Fs/Cs)y

Fβ=0.9Facotα-0.1Fr or Fβ=Fr

For Deep Groove Ball Bearings Having Nominal Contact (Angle 0°)

Fβ=3Fa-0.1Fr

For Thrust Ball Bearings Fβ=Fa

Fs: Static Equivalent Load

Cs: Basic Static Load Rating

Taper Roller Bearings• M=3.35*10-8G(nvo)1/2(ftFr/K)1/3

• M=3.35*10-8G(nvo)1/2Fa1/3

• G=dm1/2D1/6(Z.l)2/3(sinα)-1/3

• Fr/C

r or Fa/Ca≤0.59

• nvo≥2700• G is the Geometry factor based on the internal

dimensions of the bearings.• Z Number of rolling element.

Final Bar Chart

Comparision of Power Losses (W) by SKF and Analytically

Jaipur

Green field project - Gujarat

ManesarNewai

Final Result

Result

Bearing Efficiency also depends upon the Lubrication Type.

From my point of view Taper Roller Bearing is more efficient in compare to power losses at given operating condition.

Analytical Model for calculating and minimizing friction of Roller Bearings

• Catalog Method• Highly specialized Multi Body Simulation (MBS)

Figure 6:BEARINX

It is possible to select friction optimized bearing design, even in the early product development phase.

References• http://www.jbia.or.jp/e/pdf/environment.pdf (Fig : 1, 2, 3, 4 )• http://www.ntn.co.jp/english/products/review/pdf/

NTN_TR79_en_p098_103.pdf (Fig: 5)• http://www.skf.com/group/knowledge-centre/engineering-tools/

skfbearingcalculator.html• http://www.powertransmission.com/issues/0810/bearings.pdf (Fig:

6)• Rolling Bearing Analysis by Tedric A. Harris & Michael N. Kotzales

( FIFTH EDITION ) Page Number: (119 – 211)• Mechanical Design Data Book by V. S. Konnur & A. A. Memon Latest

Second Edition: 2014

Thank You ….