GB1562071A

GB1562071A - Friction clutch driven plate

Info

Publication number: GB1562071A
Application number: GB783778A
Authority: GB
Original assignee: Automotive Products PLC
Current assignee: Automotive Products PLC
Priority date: 1978-02-28
Filing date: 1978-02-28
Publication date: 1980-03-05
Also published as: FR2418380B1; DE2907045A1; FR2418380A1

Description

(54) FRICTION CLUTCH DRIVEN PLATE (71) We, AUTOMOTIVE PRO DUCTS LIMITED, a British Company of Tachbrook Road, Leamington Spa, Warwickshire, CV3 1 3ER do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to vehicle friction clutch driven plates and in particular to clutch driven plates having a device which is arranged for damping angular velocity fluctuations between a flywheel and a gear box input shaft when the torque transmitted between the flywheel and shaft is very low, such fluctuations cause idling chatter between the teeth of the meshed gears of the gear box.

According to the present invention there is provided a vehicle friction clutch driven plate comprising a hub member, a friction facing carrier capable of limited angular rotation relative to the hub member, a control plate arranged to move with the carrier for the first portion of said rotation and then to move with the hub member for the remaining second portion of rotation, the control plate being in substantially frictionally free engagement with the hub member but being frictionally engage able with the facing carrier, wherein a torque spring is connected between the carrier and the hub member so as to be loaded in torsion and thus provides an initial resistance to said rotation of the carrier relative to the hub member and other additional spring means are provided to increase the said resistarice as the degree of said angular relative rotation increases.

Preferably the control plate is carried on a sleeve concentric with and free to rotate about a portion of the hub member and is biased into frictional engagement with the facing carrier by a third spring means which is also carried by the sleeve.

Conveniently low friction materials are interposed between the hub member and the other components of the clutch driven plate.

Such low friction materials are nylon washers interposed between the hub member and facing carrier and control plate, and lubrication between the sleeve and the hub member.

It is preferable for the torque spring means to operate between 25 degrees of move- ment off centre of the facing carrier relative to the hub member.

Conveniently the other additional spring means begin to resist said limited angular rotation before the control plate frictionally engages with the facing carrier.

An embodiment of the invention will be described by way of example and with reference to the following drawings in which: Fig. 1 is a plan view of a driven plate according to this invention with a section of the facing carrier plate removed.

Fig. 2 is a section on the line II-II of Fig. 1.

Fig. 3 shows the movement of the circumferential spring at three positions of the facing carrier relative to the hub member: ti) 9" overdrive position (ii) central position (iii) 21 drive position Fig. 4 is a graph of torque load various deflections of the facing carrier relative to the hub member.

With reference to Fig. 1 and Fig. 2 the friction clutch driven plate of the type suitable for use in vehicles comprises a hub member 11 having internal splines for cooperating with the splines on a gear box input shaft and also having a radially outwardly projecting annular flange 12. The annular flange 12 is normal to the axis of the hub and is located at the approximate mid point of the axial length of the hub. A friction facing carrier 13 consists of two annular plates, a carrier plate 14 and a retainer plate 15 which are arranged to surround the hub member and are located one on each side of the flange 12.

The two plates 14 and 15 are secured to each other by three equiangularly spaced stop pins 16, each of which passes through a respective co-operating slot 17 in the outer periphery of the flange 12. The facing carrier is free to rotate relative to the hub member 12, the degree of rotation is limited by abutment of the stop pins 16 with the edges of the slots 17.

The facing carrier plate 14, retainer plate 15 and hub flange 12 each have three circumferentially extending apertures 18, 19 and 20 respectively therein. The apertures 18, 19 and 20 are aligned with each other, and form three sets of apertures each of which houses a torsion damping spring 22.

The torsion damping springs 22 resist the relative rotational movement between the friction facing carrier 13 and the hub member 11. The three sets of apertures, each respectively consisting of one of each of the apertures 18, 19 and 20 are arranged to be located between the stop pins 16. The carrier plate 14 carries the driven plate friction facing 23 on its radially outer periphery.

The hub member 11 has a concentric annular sleeve 24 on one end portion on the same side of the flange 12 as the retainer plate 15.

The sleeve 24 is free to rotate around the hub 11, and is also free to rotate relative to the retainer plate 15 through the centre of which the sleeve 24 passes. A retainer clip 25 adjacent the one end of the hub 11 holds the sleeve on the hub and the one end face 26 of the sleeve 24 adjacent the clip 25 is coated in nylon to reduce frictional engagement between the clip 25 and sleeve 24. Also lubrication such as a high temperature grease can be placed between the sleeve and the hub to reduce frictional engagement therebetween.

The other end face of the sleeve abuts a nylon washer 27 located against the flange 12 between the flange and the retainer plate 15.

The nylon washer 27 substantially reduces frictional engagement between the sleeve 24 and the flange 12. A second nylon washer 28 surrounds the hub member 11 on the other side of the flange 12 and is located between the flange 12 and the carrier plate 14 so that there is substantially no frictional engagement between the carrier plate 14 and the hub member 11.

A control plate 29 is attached to the other end portion of the sleeve 24 and lies adjacent the retainer plate 15, and is located between the retainer plate 15 and the flange 12. The control plate 29 has an annular centre portion attached to the sleeve 24 and has two diametrically opposite substantially radial projections, one projection 31 is forked and each arm 32 of the fork engages with a respective end of a spring 22 and the other projection 33 serves as a counter balance to the projection 31. The control plate 29 is frictionally engaged with the retainer plate 15 and is in substantially friction free engagement with the flange 12 because the nylon washer 27 is located between the flange 12 and the control plate 29. The control plate 29 is biased into engagement with retainer plate 15 by a belleville spring 34, located on the opposite side of the retainer plate, and acting between the sleeve 24 and a washer 36, axially slideable but rotationally fast with the sleeve 24 and abutting the retainer plate 15, so as to pull the control plate 29 against the retainer plate 15. The control plate is able to rotate relative to the retainer plate 15, the rotation being resisted by the frictional engagement with the retainer plate and is also capable of limited rotation relative to the flange 12. Each arm 32 of the forked projection 31 is arranged to project into an aperture 20 in the flange 12 and is engageable with the radial edges of that aperture to limit rotation of the control plate relative to the flange 12.

The three sets of apertures formed from the apertures 18, 19 and 20 in the carrier plate 14, retaining plate 15 and flange 12 respectively are arranged to operate the torsion damping springs 22 at different deflections of the facing carrier relative to the hub member 11. This is achieved by the matching apertures 18 and 19 in the plates 14 and 15 having different circumferential lengths to their respective co-operating apertures 20 in the flange 12.

For each set of apertures, the apertures 18 and 19 have the same dimensions and hold the spring 22 in a non prestressed state, such that the spring 22 is snugly accomodated by apertures in the facing carrier 13. The aperture 20 in the flange is circumferentially longer than the spring 22 and thus the plates 14 and 15 of the facing carrier can rotate for a predetermined amount before the spring 22 abuts the edge of the aperture 20 and begins to resist the rotation. By varying the rates of each of the individual springs 22 and by adjusting the length of free play in the apertures 20 before springs 22 begin to operate, the desired torque deflection curve (Fig. 4) can be achieved.

The springs 22 are arranged so that two springs A and B operate before the spring C which fits between the two arms 32 of the control palte 29. For the driven plate in Fig. 1 and 2 the springs 22 are arranged to operate in three steps after 14", 16", 17 , up to 22C deflection, where the stop pin 16 limits the rotation of the facing carrier relative to the hub member 11. The spring C and arms 32 of the control plate abut the edge of their respective aperture 20 in the flange 12 after 17".

On the radially inner edge of the nylon washer 28, located between the carrier plate 14 and the flange 12, is housed a circular torque spring 40 of the type having two adjacent ends and which resists relative movement between ends of the spring. One end 41 of the spring is engaged in a hole in the car rier plate and the other end of the spring is engaged with a hole in the flange 12 so that rotation of the facing carrier 13 relative to the hub member 11 moves the ends 41 and 42 of spring 40 either together or apart, this movement being resisted by the spring 40 which becomes loaded in torsion.

With reference also to Figs. 3 and Fig. 4, the driven plate in Fig. 1 is at the central position i.e. 0 deflection on Fig. 4 and with the spring 40 as illustrated in Fig. 3 (ii). If the hub member 11 is held stationary and the facing carrier 13 rotated around the hub in an anticlockwise direction, indicated by arrow 'A', then the load in the springs 22 and 40 builds up as indicated by the graph Fig. 4.

During the initial portion of rotation i.e.

0-14", the facing carrier 13 rotates about the hub 11 and this moves the ends of circular spring 40 together, thus the spring 40 acts in torsion to resist the initial portion of rotation.

Also this initial movement will bring one of the springs A and B into abutment with the edge of its respective aperture 20 in the flange, and the spring C and hence the control plate 29, will be moved with the facing carrier 13 towards the edge of its respective aperture 20 in the flange 12. The control plate 29 and sleeve 24 rotate freely around the hub 11 because of the nylon washers 27, 28 and nylon coated end face 26.

During the next period of rotation, 14-16", the torsion load in the spring 40 continues to increase and also one of the springs A and B will be deformed and start to resist rotation.

After 16 the other of the springs A and B is also brought into abutment with its respective aperture 20. The spring C and arms 32 of the control plate 29 are moved by the facing carrier 13 nearer their abutment whilst still rotating freely around the hub member 11.

During the next period of rotation, up to 17 , the circular spring 40, and the springs A and B resist the relative rotation and at 170 the spring C and arms 32 of the control plate 31 are moved into abutment with the edge of its respective aperture 20.

During the final phase of rotation 17-22 the circular spring 40 and springs A, B and C resist the rotation. Also the control plate 29 which was rotating relative to hub 11 now abuts the hub member 11 with its arm 32 and hence over the period of rotation between 17 and 22 the control plate, now stationary, moves relative to the facing carrier 13.

Since the control plate 29 is in frictional engagement with the retainer plate 15 under the bias of the belleville spring 34 a degree of friction damping is introduced into the rotational movement between the facing carrier 13 and hub member 11. This gives rise to the hysterisis shown on Fig. 4. The deflection curve will continue until the stop pins 16 abut the ends of their respective slots 17. Fig. 3 (iii) shows the ends of the spring 40 at 21 drive deflection.

When the load is slowly removed from the driven plate the springs return the facing cam rier 13 in a clockwise direction. At the 17 the spring C picks up on both the arms 32 of the control plate again and the other springs A and B which are still stressed move the facing carrier and control plate back to 14 .

Hence the set of sPrings 22 (i.e. individual springs A, B and C return the control plate back to 140. After 14" since no friction damping is operating the spring 40 moves the facing carrier back to its 0 position with respect to the hub member. Should the driven plate go past the 0 position into overdrive, for example in slowing a car on the gearbox, then the clearances between the springs A, B and C and their respective apertures 20 are made less than for the drive direction. The plate is arranged to operate against the spring 40 and one of the springs A and B between 0 to -2", and the spring 40 and both the springs A and B between -2" to -4", and all the springs and the control plate friction damping between -4" to -9 .

WHAT WE CLAIM IS: 1. A vehicle friction clutch driven plate comprising a hub member, a friction facing carrier capable of limited angular rotation relative to the hub member, a control plate arranged to move with the carrier for the first portion of said rotation and then to move with the hub member for the remaining second portion of rotation, the control plate being in substantially frictionally free engagement with the hub member but being frictionally engageable with the facing carrier, wherein a torque spring is connected between the carrier and the hub member so as to be loaded in torsion and this provides an initial resistance to said rotation of the carrier relative to the hub member and other additional spring means are provided to increase the said resistance as the degree of said angular relative rotation increases.

2. A clutch driven plate as claimed in Claim 1, wherein the control plate is carried on a sleeve concentric with and free to rotate about a portion of the hub member and is biased into frictional engagement with the facing carrier by a third spring means which is also carried by the sleeve.

3. A friction clutch driven plate as claimed in Claim 2 wherein the facing carrier comprises two annular plates arranged one either side of a flange on the hub member, and the control plate is located between one annular plate and the hub flange and the third spring means is arranged on the side of the one annular plate away from the flange and acts to bias the control plate against the one annular plate.

4. A friction clutch driven plate as claimed in any one of Claims 1 to 3, wherein the torque spring is a circular spring having

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. rier plate and the other end of the spring is engaged with a hole in the flange 12 so that rotation of the facing carrier 13 relative to the hub member 11 moves the ends 41 and 42 of spring 40 either together or apart, this movement being resisted by the spring 40 which becomes loaded in torsion. With reference also to Figs. 3 and Fig. 4, the driven plate in Fig. 1 is at the central position i.e. 0 deflection on Fig. 4 and with the spring 40 as illustrated in Fig. 3 (ii). If the hub member 11 is held stationary and the facing carrier 13 rotated around the hub in an anticlockwise direction, indicated by arrow 'A', then the load in the springs 22 and 40 builds up as indicated by the graph Fig. 4. During the initial portion of rotation i.e. 0-14", the facing carrier 13 rotates about the hub 11 and this moves the ends of circular spring 40 together, thus the spring 40 acts in torsion to resist the initial portion of rotation. Also this initial movement will bring one of the springs A and B into abutment with the edge of its respective aperture 20 in the flange, and the spring C and hence the control plate 29, will be moved with the facing carrier 13 towards the edge of its respective aperture 20 in the flange 12. The control plate 29 and sleeve 24 rotate freely around the hub 11 because of the nylon washers 27, 28 and nylon coated end face 26. During the next period of rotation, 14-16", the torsion load in the spring 40 continues to increase and also one of the springs A and B will be deformed and start to resist rotation. After 16 the other of the springs A and B is also brought into abutment with its respective aperture 20. The spring C and arms 32 of the control plate 29 are moved by the facing carrier 13 nearer their abutment whilst still rotating freely around the hub member 11. During the next period of rotation, up to 17 , the circular spring 40, and the springs A and B resist the relative rotation and at 170 the spring C and arms 32 of the control plate 31 are moved into abutment with the edge of its respective aperture 20. During the final phase of rotation 17-22 the circular spring 40 and springs A, B and C resist the rotation. Also the control plate 29 which was rotating relative to hub 11 now abuts the hub member 11 with its arm 32 and hence over the period of rotation between 17 and 22 the control plate, now stationary, moves relative to the facing carrier 13. Since the control plate 29 is in frictional engagement with the retainer plate 15 under the bias of the belleville spring 34 a degree of friction damping is introduced into the rotational movement between the facing carrier 13 and hub member 11. This gives rise to the hysterisis shown on Fig. 4. The deflection curve will continue until the stop pins 16 abut the ends of their respective slots 17. Fig. 3 (iii) shows the ends of the spring 40 at 21 drive deflection. When the load is slowly removed from the driven plate the springs return the facing cam rier 13 in a clockwise direction. At the 17 the spring C picks up on both the arms 32 of the control plate again and the other springs A and B which are still stressed move the facing carrier and control plate back to 14 . Hence the set of sPrings 22 (i.e. individual springs A, B and C return the control plate back to 140. After 14" since no friction damping is operating the spring 40 moves the facing carrier back to its 0 position with respect to the hub member. Should the driven plate go past the 0 position into overdrive, for example in slowing a car on the gearbox, then the clearances between the springs A, B and C and their respective apertures 20 are made less than for the drive direction. The plate is arranged to operate against the spring 40 and one of the springs A and B between 0 to -2", and the spring 40 and both the springs A and B between -2" to -4", and all the springs and the control plate friction damping between -4" to -9 . WHAT WE CLAIM IS:

1. A vehicle friction clutch driven plate comprising a hub member, a friction facing carrier capable of limited angular rotation relative to the hub member, a control plate arranged to move with the carrier for the first portion of said rotation and then to move with the hub member for the remaining second portion of rotation, the control plate being in substantially frictionally free engagement with the hub member but being frictionally engageable with the facing carrier, wherein a torque spring is connected between the carrier and the hub member so as to be loaded in torsion and this provides an initial resistance to said rotation of the carrier relative to the hub member and other additional spring means are provided to increase the said resistance as the degree of said angular relative rotation increases.

two adjacent ends and which resists relative movement between the ends.

5. A friction clutch driven plate as claimed in Claim 4, wherein the torque spring is located between the hub flange and the other annular plate, and one end of the torque spring engages with the hub and the other end of the spring engages with the other annular plate.

6. A friction clutch driven plate as claimed in any one of Claims 1 to 6, wherein low friction materials are interposed between the hub member and other components of the clutch driven plate.

7. A clutch driven plate as claimed in any one of Claims 1 to 6, wherein the torque spring operates between approximately t25 degrees of movement off centre of the facing carrier relative to the hub member.

8. A clutch driven plate as claimed in any one of Claims 1 to 7, wherein the other additional spring means begin to resist the angular rotation before the control plate frictionally engages with the facing carrier.

9. A clutch driven plate as claimed in any one of Claims 1 to 8, wherein the control plate is an annular plate having two substantially diametral projections, one of the projections is forked so that each arm of the fork engages with a respective end of a spring means, and the other projection provides a counter balance to said one projection and increases the area of frictional engagement between the control plate and the facing carrier.

10. A clutch driven plate substantially as described herein and as shown in the accompanying drawings.