Arpa Dec 2008

///MMT Single Phase Rotary Actuators Basic Information

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Also called Limited Angle Torquers or Torque Motors

MM13 EP#0429625

USA#5,298,825 MM18

EP#642704 USA#5,512,871 Japan#03021046

MM22 EP#0558362

USA# 5,334,893 Japan#3250860

MM55 FR#2786042

USA#6,313,553 MM91

FR#2849712

Basic Information for Evaluation Purpose

MMT - DA

MMT Technology for Single Phase Rotary Actuators

Moving Magnet Technologies SA ZAC Lafayette 1, rue Christiaan Huygens F-25000 Besanon France Tel 03 81 41 42 00 International +33 3 81 41 42 00 Fax 03 81 51 83 06 International +33 3 81 51 83 06


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Moving Magnet Technologies S.A ZAC La Fayette 1, rue Christiaan HUYGENS F - 25 000 Besanon : +33 3 81 41 42 00 : +33 3 81 51 83 06 Web : www.movingmagnet.com


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SUMMARY

1. MMT proportional actuators 4 1.1 Working principle 4

1.2 Disc magnets embodiments 6 1.2.1 Two poles/ two coils design 6

1.2.2 Two poles / one coil design 7

1.2.3 4 poles designs 8

1.3 Ring magnet embodiments 11 1.3.1 Two poles designs 11

1.3.2 4 poles designs 12

1.4 Tile magnet design MM55 12 1.4.1 MM55 Structure 13

1.4.2 MM55 Working principle 13

1.4.3 Prototype measurement 14

2. MMT bi-stable actuator 16 2.1 MM91 structure 16

2.2 MM91 working principle 16

2.3 MM91 prototype and measurement 18

3. Applications 19 3.1 Automotive engine management 19

3.2 Other automotive applications 20

3.3 Non automotive applications 22

4. Patent situation 23


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1.1 Working principle The principal features of MMTs technology are the following: A constant torque over the stroke A reversed torque for a reversed current A torque proportional to current (proportional actuator) This drawing explains the basic principle of our technology: a two-pole magnet is placed between two 3-pole stators, a coil being wrapped around the central pole of each stator. When the coils are supplied, a varying magnetic field is created between the stators and the magnet will move in order to align with that field. The force created that way on the magnet is constant upon the whole useful stroke and is strictly proportional to current input.

The force created is expressed by:

nI.Z.EL.Br2F =

Br is the magnetic remanence of the magnet, L the thickness of the magnet, E the thickness of the gap, Z the width of the mechanism, nI the number of Amperes-turns in the coil. nI is calculated by: P is the electrical power in the coil and Ro is the coil resistance divided by the coils wire turns number squared.

RoPnI =

E/2 E/2

Stroke

EL

Stator

Coil

Magnet

1. MMT proportional actuators


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MMT rotary actuators are simply created from that basic design by rolling it around an axis. Lets indeed imagine that we do roll the actuator described around X-axis : the magnet becomes a 2-pole disc one and the motion created is a limited angle rotary one at constant torque.

Lets now imagine that we roll it around Y-axis : the magnet becomes a ring and the mo-tion created is also rotary.

That defines the main structures of our rotary actuators that will be presented there: ac-cording to the structure chosen and to the number of pole pairs used, every torquer user should find there a efficient, compact and reliable solution for rotary actuation purpose.

X

The datasheet here after provides you with the main characteristics of that family of actua-tors.

Y


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1.2 Disc magnet embodiments 1.2.1 Two poles + two coils designs

Such actuators can be designed to provide strokes up to 150. The actuator uses at least one bearing, preferably of the axial type in order to withstand the axial force due to the permanent magnet. Standard actuators use an additional ball bearing to withstand external forces perpendicular to the shaft. Simple sleeve bearing can be used if these forces are not too high. The magnet is glued onto a yoke of soft magnetic material.

Coil

Two-pole magnet

Moving yoke

Stator

Bearing

Axial bearing To

tal h

yste

resi

s

110 14

Additional stroke providing a detent torque to keep the rotor against the stop

180

0

69 W

44 W

2.77 W

11 W

25 W

Typical measurement curves


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Typical sizes and related specifications (R35, R50, R75) ARPA R35/90 R50/110 R75/110Stroke () 90 110 110Rated Joule Power (W 100% duty cycle) 7 13,5 23,5Duty rating ED (%) 100 40 25 15 5* 100 40 25 15 5* 100 40 25 15 5*Power consumption (W) 7 15,8 25 38 82 13,5 25,8 49,1 79,8 177 23,5 47 77,1 137 311Torque (mNm) 33 49,6 62,4 76,9 113 120 166 229 292 434 400 566 725 967 1455Reference of temperature (C) 20 20 20Outer diameter (mm) 35 50 75Length (mm) 28 37 53Mass (kg) 0,15 0,36 1,2Inertia (kg.m)Electrical time constant (ms) 4,5 5,5 7

1,57E-06 1,11E-05 1,10E-04

*: d

epen

dant

on

the

mag

net g

rade

1.2.2 Two poles + one coil design

Yoke

Axial ball bearing

2-pole ring magnet

Coil

Stator

Compared with previous structure, we have decrease the number of parts, and so simplify the design. It has to be noticed that with this type of structure, a shaft going through the actuator is not easily available.


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ARPA 2P1B

OD = 50

Over-all dimension

OD 50 x h 50

Magnet dimension

OD 50 x ID 23 x

h 3

Magnet remanence Br

1.12 T

Total weight

520g

Torque constant

235 mNm/A

Coil resistance

4.25 Ohms

Thermal resistance coil-air

9.2C/W

Power available @ 125C During 10 min

Max coil temp: 180C / magnet: 150C

12W

Motor constant @ 25C

115mNm/W1/2

Motor constant @ 125C

85.5mNm/W1/2

Torque available @ 125C during 10 min

301 mNm

Available stroke 90

With this structure, at ambient temperature with 1.4A (8.3W), we generate a torque higher than 300 mNm on 90 stroke

1.2.3 4 poles designs

For smaller strokes than 90, a structure with more than two stator poles can be imple-mented. Then, by using more pole pairs, we will get more output torque for a same input electrical power. The four-pole structure covers strokes from 30 to 80, the permanent magnet being then magnetized with four pole-pairs. For less than 30, the stator can use a six-pole arrangement, the permanent magnet being magnetized with six-pole pairs. The torque is then 3 times larger than that of the two-pole structure for the same number of Amperes-turns applied to each coil.

4-pole magnet

Yoke

Shaped pole

Coil

Base

Thrust bearing


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The actuator shown on the figure here above is typical of 4-pole actuators designed for 80 strokes : the pole is made wider at its top in order to increase the useful stroke with-out loosing any useful place for copper volume.

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Torque = 0.28 Nm @ 10 WTorque = 0.28 Nm @ 10W

4-pole rotary actuator Magnet 42 mm Outer 50 mm

Detent torque

The typical performances of that kind of actuator are provided in the array here below ac-cording to the size and power input.

Units 36 42 51

Continuous stall supply power (100% of duty cycle) W 8.4 10 30

Continuous stall torque (100% of duty cycle) mNm 138(1) (P=8.4W)

250(1) (P=10 W)

800(2) (P=30.8W)

Peak supply power W 50 50 60

Peak torque mNm 360 540 1100

Useful stroke 75 75 75

Resistance 2.6 3.1 3

Inductance mH 15 36 22

Overall dimensions mm 54 x 52* 54 x 60* 67 x 57*

Rotor inertia g.cm 57* 155* 345*

Mass g 320* 470* 700*

(* delivered in a plastic housing and integrated position sensor http://www.sonceboz.com/html/en/products_torque.htm ) (1) Actuator measured in ambient air @ 25C (2) Actuator measured in a ventilated oven @ 25C


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36 42

51


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1.3 Ring magnet embodiments 1.3.1 Two poles designs

Strokes over 90 can also be obtained with ring magnet actuators. The advantages of those structures compared to disc ones are the following: Stator can be made of laminations : lower cost and more precise solution Symmetrical structures : forces are equilibrated Radial air gaps are easier to achieve than axial ones The disadvantage of that solution is that the magnet is still expensive in such shapes.

ARPA 2-pole, ring magnet rotary actuatorStroke ()Duty cycle (%) 100 50 20Power consumption (W) 15 30 75Torque (Nm) 0,6 0,82 1,3Reference of temperature (C)Resistance (ohms)Outer dimensions (mm)Weight (kg) 1,02

140

201,5

71*76*42

Such actuator can be realized either with one or two coils according to your specific re-quirements in terms of output torque, input power and available volume.

Coil

Stator

2-pole magnet

Coil

1 pole pair ring magnet

Stator stack of lamination


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1.3.2 4 poles design

Coil

Rotary posi-tion sensor

Laminated stator

Magnet tile

End stop

ARPA 4-pole, ring magnet rotary actuatorStroke ()Duty cycle (%) 100 50 20Power consumption (W) 16 32 80Torque (Nm) 1,07 1,5 2,4Reference of temperature (C)Resistance (ohms)Outer dimensions (mm)Weight (kg)Inertia (kg.m)Electrical time constant (ms)

2,033,60E-05

11,4

32

256,4

56 * 62 * 53

Ring multipolar magnet actuators can also be realized. Here below is shown an example of design for a high torque, low stroke ring magnet rotary actuator.

1.4 Tile magnet design MM55 In order to decrease the magnet volume in this proportional, we have developed a new structure using only one unipolar tile magnet embedded into the rotor. With this lower cost structure, we generate a reluctant effect which give a slope to the torque curve as a func-tion of the position as shown here after.


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1.4.1 MM55 Structure

Stator stack of lamination Rotor stack

of lamination

Tile magnet embedded

into the rotor

Coil (copper wounded on a plastic bobbin)

1.4.2 MM55 working principle In MM55, the torque generated is the sum of proportional torque Tni and the reluctant torque T(ni) with:

And With: - Br the magnet remanence (T) - Rm the magnet mean radius (m) - Z the height of the stack of lamination (m) - nI the current supplied (At) - L the magnet thickness L=R3-R1(m) - E the total air gap E= R4-R1 (m) - e the embedded height e=R2-R1 (m) - 0 air permeability We can notice that when e=0, Tni=0

a

p R1R3R4

R2

ap R1

R3R4R2

nIeE

LZRBnIT mrni == 22

22

)( )(12)()(

21 nI

baabbaZT

poni

+

=

2

4lnRRa =

1

4lnRRb =


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Based on these torque formulas, we can plot the following torque vs. position curve for the MM55 actuator:

We can notice that the higher the current is applied, the higher the reluctant torque is. Due the physical limitation of the tile magnet we have a stroke limitation around 90 for this type of actuator. 1.4.3 Prototype measurement

Tni(1)

Max 90

Tni(2) +Tni(2)Tni(2)

Torq

ue

Position

Tni(1) +Tni(1)


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With this prototype using a magnet mass of 15g. And a remanence of 1T., we generate 300 mNm over stroke with 8W electrical power. Each of our proportional rotary actuator structures can be adapted to your requirements in terms of output torque, electrical power input, resistance We will be pleased to provide you with any further information you need and to recommend you the kind of actuator that should be suited to your need.


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2. MMT bi-stable actuator On some other application, there is also a need for some stable equilibrium position without current on the end of stroke. MMT has developed some structures using the interaction between the magnetic circuit (soft magnetic material) and the permanent magnet to generate a locking torque on the end of the stroke position. This bi-stable structure is called MM91 2.1 MM91 structure On the basis of the MM55 proportional structure, MMT has added a specific shape to the rotor to generate some reluctant effect on the end of the stroke position as show hereafter: 2.2 MM91 working principle In the following view, we will the flux lines in MM91 structure during several working modes in order the understand the specific features of this structure:

-Without current-

STABLE POSITION due to the magneto-static torque

-Coil supplied against the magnet-

Beginning of the stroke: Important variation of the magnet flux in the coilHigh torque available = UNSTICKING

Quasi-proportional torque area

Reluctant torque area


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With this MM91 structure, we have the following torque versus position typical curve:

-Supplied coil-

In the middle of the stroke : Torque quasi-proportional to the current

-Coil supplied with the magnet-

End of the stroke : Electro magnet actuator, important sticking torque

CCtotaltotal = C= Cnini + + CCnini + C+ C00

Due to the coil alone Due to the interaction between coil and magnet

Due to the magnet alone

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90

Position []

Cni Co Cni


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2.3 MM91 prototype and measurement

In order to cancel the radial forces generated in this non-symmetrical structure, MMT has also worked on the design hereafter:

36.8 mm

48 mm

18 mm (iron)33 mm (coil)

Magnet weight 3.8 gRotor weight 33 gStator weight 94 gCopper weight 39.5 g

Total 170.3 g

-0.2

-0.18

-0.16

-0.14

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

-45 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45

Position []

Cou

ple

[Nm

]

C0 1.9W (0.5A) 4.9W (0.8A) 7.7W (1A) 13W (1.3A)

Valeurs au dcollage (-45)

Unsticking torque values (-45)


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3.1 Automotive Engine Management In order to withstand the more and more stringent automotive emission regulation (US EPA07, Euro 5, ) and increasing demand to fuel consumption reduction to counterbalance the increase in gas price, modern engines requires more and more regulation valves. MMT rotary actuators are used in a wide range of engine management application for electrical regulation of these valves as shown hereafter:

3- Applications

Exhaust Gas Recirculation (EGR) valve on diesel engine

Variable Geometry Turbo (VGT) actuator on diesel engine


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Manifold Vacuum Regulator Valve (MVRV) actuator on diesel engine

Manifold Tuning Valve (MTV) actuator on gasoline engine

Electronic Throttle Control (ETC) actuator and sensor on gasoline engine


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3.2 Other automotive applications Our rotary actuators are also used to generate 2 Nm torque for force feedback in the accel-erator pedal.

EGR bypass cooling valve actuator


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3.3 Non automotive applications

Our rotary actuators are also used for the following applications:

Laser beam deviation

Payment machines

Force feedback gamepad

Mecatronic lock


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4-Patent situation MM13 Actionneur lectromagntique monophas de faible encombrement (electromagnetic monophase rotary actuator having small overall dimensions) Priority France June 16, 1989 French patent granted on October 4, 1991, # FR 2 648 632 PCT application # WO9016107 publicized on December 27th 1990 EP # 0429625 (D, UK, FR, E, I, CH, NL) granted on September 6th 1995 Japan patent #180803/99 filed a second time on June 25, 1999 (iniial filing on June

15th 1990) USA patent # 5,298,825 granted on March 29,1994. MM18 (improvement to MM13) Actionneur lectromagntique monophas rotatif (electromagnetic monophase rotary actuator) Priority France December 17, 1990 French patent granted on March 10, 1995, # 2670629 PCT application # 9211686 of December 16, 1991 EP # 0642704 granted August 21st 1996 Japan patent #03021046 granted on March 15th, 2000 USA patent # 5,512,871 granted on April 30,1996. MM22 (actuator arrangement not dependant on MM13, MM18) Actionneur rotatif lectromagntique monophas de course entre 60 et 120 degrs (monophase electromagnetic rotary actuator of travel betwenn 60 and 120 degrees) Priority France February 28, 1992 French patent # 2688105 granted on May 6th 1994 Patent filed directly in USA and japan without using the PCT procedure EP # 0558362 ( D, UK, FR, I, CH) granted on August 28th 1996 Japan patent #03250860 granted on November 16, 2001 USA patent # 5,334,893 granted on August 2,1994. MM55 Actionneur avec rotor homopolaire et aimants encastrs dans le fer (Rotating electromagnetic actuator comprising at least one magnet embedded in ferromag-netic material) Priority in France November 13th 1998 French patent #2786042 granted on December 15th 2000 European patent #1001510 (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT,

LI, LU, MC, NL, PT, SE) publicized on May 17th 2000 US patent #6313553 delivered on November 6th 2001 Japan patent #2000152590 publicized on May 30th 2000 MM91 Actionneur rotatif bistable mono-phase hybride (Hybrid single phase bi-stable rotary actuator) Priority in France January 7th 2003 French patent #2849712 granted on May 20th 2005 PCT application #WO04066476 for Europe, Japan and USA publicized on October 5th

2004

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Arpa Dec 2008