GB2273335A

GB2273335A - Clutch plate with friction damping device

Info

Publication number: GB2273335A
Application number: GB9325379A
Authority: GB
Inventors: Reinhard Feldhaus; Harald Jeppe
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1992-12-10
Filing date: 1993-12-03
Publication date: 1994-06-15
Anticipated expiration: 2013-12-03
Also published as: BR9304992A; ES2068774A2; ITMI932307A1; FR2699242B1; ITMI932307A0; ES2068774B1; GB9325379D0; IT1266527B1; GB2273335B; ES2068774R; FR2699242A1

Abstract

A friction clutch plate comprises a hub 6, a central disc-like component 36 and two outer such components 8, 9, together with coiled damping springs 13 which, with parallel friction devices 21, 22, provide the basic damping over the whole angle of relative rotation. Further damping, dependent upon angle, is provided in parallel through a control element 15 located radially inside springs 13 and between components 8 and 36. The element 15 has axially directed noses 18 which engage circumferentially larger openings 32 in component 8 and further noses 17 engaging openings 33 in component 36 with the interposition of circumferentially acting pre-loaded elastomeric springs 34. The springs 34 may alternatively lie in the component 8 (FIG 5) and the outer disc-like components may alternatively be secured to the hub (FIG 6). <IMAGE>

Description

CLUTCH PLATE WITH ADD-IN FRICTION DEVICE The invention relates to a clutch plate for a friction clutch for motor vehicles, and in particular to such a clutch plate comprising a hub with internal splines concentric with an axis of rotation, three disc-like components arranged axially side by side, of which either a central one is secured to the hub and the two outer ones are secured to one another and provided in a radial outer region with friction linings and energy-storing springs between the two kinds of component for mutual relative rotation against the force of the springs or the middle one is connected to the friction linings and the two side ones are arranged to be secured on the hub, further comprising at least two damping devices of which one is in action over the whole range of relative angular movement, and the other is brought into action in dependence on angle and co-operates with a pre-loaded spring device in a parallel arrangement through a control element, which spring device returns the damping device on reversal of the direction of loading, the control element being arranged between the central and one lateral disc-shaped component.

A clutch plate of this kind is known for example from German patent specification 32 30 663. In the known solution a control element is provided for controlling a friction device which is of disc like shape, has a large radial extent and which co-operates with circumferentially distributed torsion springs.

The construction is relatively voluminous and the control element significantly increases the moment of inertia of the clutch plate.

It is accordingly the aim of the present invention to improve a clutch plate of the above-mentioned construction significantly so that a lower moment of inertia can be achieved and the overall construction is more compact.

This problem is solved according to the invention by a clutch plate for a friction clutch for motor vehicles comprising a hub with internal splines concentric with an axis of rotation, three disc-like components arranged axially side by side, of which either a central one is secured to the hub and the two outer ones are secured to one another and provided in a radial outer region with friction linings and energy-storing springs between the two kinds of component for mutual relative rotation against the force of the springs or the middle one is connected to the friction linings and the two side ones are arranged to be secured on the hub, further comprising at least two damping devices of which one is in action over the whole range of relative angular movement, and the other is brought into action in dependence on angle and co-operates with a pre-loaded spring device in a parallel arrangement through a control element, which spring device returns the damping device on reversal of the direction of loading, the control element being arranged - between the central and one lateral disc-shaped component, in which the control element is arranged radially inside the energy-storing springs and has axially directed noses which engage in corresponding circumferentially larger first openings in one of the disc-shaped components and further axially directed noses which engage in second openings in the other disc-shaped components, with the interposition of a circumferentially acting spring device.

By arranging the control element radially within the energy-storing springs on the one hand the moment of inertia of the clutch plate is significantly reduced and on the other hand the space radially outside the control element can be fully employed for mounting the springs. Moreover the axial extent of the clutch plate in the region of the springs is very compact.

According to a further feature of the invention it is proposed that the control element should be arranged directly radially inside the springs and the friction device for the basic friction should be arranged between the control element and the hub. By this arrangement the friction rings and the springs for the two different friction devices can be radially intercalated over one another and accordingly take up a small amount of space in an axial direction.

According to a further feature it is however also possible to arrange axially on both sides of the central disc-shaped component, eg the hub disc, on the one side a friction ring for the basic friction and on the other side a control element with two friction rings, and here the one friction ring is in action until the introduction of the control element and thereafter over the further angular range the introduction of the other friction ring takes place.

In this way a radially very compact construction for the friction device is obtained. Furthermore the number of individual components which are required is kept to the minimum.

In this connection, in an advantageous manner a plate spring is introduced for generating the force for the friction device, which also can achieve a flat spring characteristic on increasing wear and which accordingly takes care of the damping force for the entire friction force component.

In this arrangement the friction values of the friction rings are matched or tuned with regard to the pre-load force of the spring device co-operating with the control element so that the first damping force is smaller than or equal to the pre-load force of the spring device co-operating with the control element plus the second damping force. In this way we ensure that with the present construction the feed back action by the pre-load force of the spring device is ensured in every case.

The openings in the central disc-shaped component could, in this arrangement, preferably be made in one piece with windows for the energy-storing springs.

Such a embodiment brings with it advantages from the point of view of manufacture and of strength.

According to a further feature the first openings are preferably arranged in the central disc-shaped component. This brings particular advantages for the central disc-shaped component from the strength point of view if small free angles are provided, after which the introduction of the control element takes place, as in this case the corresponding openings can be made circumferentially short.

According to a further feature of the invention it is proposed that the pre-loaded spring device should be in the form of an elastomeric element in which the noses of the control element are embedded. Such an embodiment allows for example a mounting of the spring device which is very economical in space in a radial direction. Moreover it is possible, using such a material, to bond the spring element to the control sheet or to the opening in which it is present by vulcanising. In this way a deliberate reinforcement both in a circumferential direction and also in an axial direction can be achieved.

The control element is, in an advantageous manner, provided in the region of its outer periphery and in the region of its inner periphery with axially directed noses which point in different axial directions. In this way the control element is easy to produce, for example from a simple sheet metal pressing, and to mount in a space-saving manner.

The invention is further explained in the following in conjunction with a number of examples. In the drawings in detail: Figure 1 shows the upper half of a longitudinal section through a clutch plate; Figure 2 is a diagrammatic illustration of the principle of operation; Figure 3 shows a further embodiment of a clutch plate; Figure 4 shows a diagrammatic illustration of the principle of operation of Figure 3; Figure 5 shows a further embodiment of a clutch plate; Figure 6 shows a further embodiment of a clutch plate; Figures 7 and 8 show details of the actuation of the control element; Figure 9 shows the build-up of torque and build-up of friction force in accordance with angle of relative rotation.

Figure 1 shows the upper half of a longitudinal section to an enlarged scale through a clutch plate 1.

It comprises a hub 6 which is arranged concentrically with relation to an axis of rotation 5. Integral with the hub 6 is a radially outwardly projecting hub disc 36. This forms the central disc-shaped component of the clutch plate 1. On opposite sides of the hub disc 36 are the two other disc-shaped components in the form of a lining carrier 8 and cover plate pressing 9.

These two are connected together securely and at the same time spaced apart by means of rivet pins, not shown. Spring energy-storing devices in the form of coil springs 13 are arranged in correspondingly shaped windows both in the hub disc 36 and also in the lining carrier 8 and in the cover pressing 9, and they are compressed when the clutch plate 1 is subjected to torque. The lining carrier 8 carries friction linings 14 in its radially outer region. The lining carrier 8 and the cover pressing are guided radially on the hub 6 and various damping devices are arranged in the radial space between the hub 6 and the springs 13.

The damping device arranged radially further in is in the form of a pure friction device and it comprises friction ring 21 which is arranged between the cover pressing 9 and the hub disc 36 as well as a friction ring 22 on the opposite side, which is clamped to the hub disc 36 through a backing ring 35 and a plate spring 28. The plate spring in this arrangement abuts with its one diameter against the backing ring 35 and with its other against the lining carrier 8. The backing ring 35 is held against rotation, but axially free, by axially extending noses engaging in openings 31 in the lining carrier 8. The flow of force is produced through the rivet pins, not shown. This friction device ensures the provision of the basic friction which is effective over the entire range of relative angular movement of the clutch plate 1.In the radial space between this basic friction device and the coil springs 13 there is arranged a further damping device which is not effective over a first free angle and then subsequently is additionally effective up to the end of the whole range of angle of relative rotation. It comprises both a spring device and also a friction device. For this purpose a control pressing 15 is provided, which has an annular body which in the present case is arranged between the lining carrier 8 and the hub disc 36. Projecting from the basic body in both axial directions are a number of noses 17 and 18, the noses 18 engaging with circumferential play in openings 32 in the lining carrier 8. The noses 17 which project in the other direction project through openings 33 in the hub disc 36, again with circumferential play but in this case case this play is filled by an elastomeric spring 34.The elastomeric spring 34 is installed with a deliberate circumferential pre-load. The noses 17 extend further in an axial direction beyond the springs 34 and are secured against rotation and axial movement to a radially extending ring 30 which engages the hub disc 36 through a friction ring 25. On the side of the hub disc 36 opposite the ring 30 there is provided a further friction ring 26 which is acted on axially by a plate spring 29 which abuts on the one hand against the basic body of the control element 15 and on the other hand against this friction ring 26. There are several of the noses 18 and the openings 32 distributed circumferentially and the same is true of the noses 17 and the springs 34.

The manner of operation of the clutch plate 1 is explained further in connection with Figs 2 and 9, and the principle can also be derived from Figs 7 and 8.

From the diagram of the principle shown in Figure 2 it can be seen then there is provided between the two input and output components, shown cross-hatched, a basic spring action which is derived from the coil springs 13 and which for example in Fig 9 has a continuous spring characteristic of stiffness C 1 It is naturally possible in principle to add the coil springs 13 into the action individually after a predetermined angle of relative rotation, so that the spring characteristic takes up a kinked path. In parallel with this device there is provided a friction device for the basic friction which produces the friction moment MR1 and which is achieved by the components 21,22,28,35. This basic friction MR1 is in action over the whole angle of relative rotation.

Accordingly the basic friction and the spring device represent the basic damping device.

After a predetermined angle of relative rotation a ) ss (symmetrically or unsymmetrically distributed between the tension and compression) corresponding to the play between the openings 32 in the lining carrier 8 and the noses 18 of the control element 15 there is brought in a second damping device.This comprises the arrangement, connected in parallel, of the elastomeric springs 34 having the spring characteristic C2 and the pre-load torque Mo2 and the friction device having the friction torque NR2 In order to achieve a return of the control element 15 to its rest position in a reliable way on a reverse of the direction of rotation within the clutch plate 1, in this arrangement the pre-load force of the elastomeric springs 34 with their torque N02 must be at least equal to or larger than the friction torque MR2 of the friction device. At the same time it is of advantage if the spring characteristic C2 extends as flat as possible as the friction force should be derived substantially as a damping element.In this way we ensure that, within the entire angle of relative rotation in which the coil springs 13 are in action, the additional friction force having the torque MR2 can be added at practically any desired point. Accordingly overall there occurs a course of the damping forces in accordance with Figure 9, which within the relative rotation angle a, ss comprises the basic springing having the characteristic C1 as well as the basic friction torque MR1 effective in parallel with it, and after the addition of the further damping device the spring characteristic is made up of a combination of the individual characteristics C1 plus C2 as well as the combined friction force MR1 plus MR2. On subsequent reversal of the direction of rotation the friction force MR2 remains maintained by the pre-load force of the elastomeric springs 34 until the control pressing 1.5 is shifted back to its central position in relation to the hub disc 36 by the elastomeric springs 34.

With this construction the basic friction device can be made completely independent of the damping device which comes in later.

In Figure 3 is shown a further embodiment by way of example, which is explained further in conjunction with Figures 4,7,8 and 9. The clutch- plate 2 shows a construction which ends up with fewer individual components and taking up a minimum of radial space.

The components 6,36,8,9,13 and 14 are taken in principle from Figure 1. Between the cover pressing 9 and the hub disc 36 there is arranged a friction ring 21 which is effective over the whole range of relative rotation and which produces the friction torque MR1. Arranged on the opposite side is the control element 16 which has noses 19,20 extending axially in different directions at its outside diameter and at its inside diameter and which serve for control. The friction ring 24 is arranged between the control element 16 and the lining carrier 8 and a friction ring 23 and a plate spring 27 are arranged opposite the hub disc 36. The noses 19 arranged at the outer periphery of the control element 16 extend into openings 33 in the hub disc 36 or with the interposition of elastomeric springs 34 which are pre-loaded in a circumferential direction.The noses 20 arranged at the inner periphery of the control element 16 extend in the other direction and there they extend into openings 32 which are circumferentially larger in extent, in the lining carrier 8. The plate spring 27 and the friction ring 23 are arranged to be secure against rotation but axially free with respect to the noses 19 on the control element 16.

The manner of operation of the clutch plate 2 is as follows: as already explained in principle with respect to Figure 1 the steepness of the spring characteristic CR2 should extend as flat as possible so that at least in the region of the add-in friction device the spring characteristic shows no significant kinks. In this way the introduction of the friction can be achieved independently of other add-in coil springs 13. Within the first range of relative angular rotation a , ss the coil springs 13 are effective with the spring characteristic C1, and in parallel the action of the friction ring 21 having the friction torque MR1 and in parallel with that the friction torque MR3 produced by the friction ring 24.In fact during this first range of relative angular rotation the control element 16 is held securely in its relative position in relation to the hub disc 36 by the pre-load force of the elastomeric springs 34. The force for producing the friction is prepared by the plate spring 27. When the angle a 8 ss of relative rotation is exceeded the control element 16 is forceably taken along by the end stops of the openings 33 in the lining carrier 8, causing the friction ring 24 to lose its function, but the friction ring 23 comes into action for this purpose.This friction ring 23 acts with a friction torque having the magnitude MR2 In order to be able to maintain the operation described, the following requirements must be maintained in this connection: the pre-load torque N02 of the elastomeric springs 34 must be greater than or equal to the friction torque MR2 of the friction ring 23 and the friction torque MR3 must be smaller than or equal to the sum of the pre-load torque Mo2 plus the friction torque MR2 In this connection in Fig.9 the value in brackets M plus MR3 in the range of angle a , ss relates to the construction shown in Figure 3.

Figures 7 and 8 show partial views to a larger scale illustrating the arrangement of the noses 19 in the openings 33 in the hub disc 36, bringing in the elastomeric springs 34. The springs 34 in this arrangement are provided with a relatively large circumferential extent whereas in the radial direction they only have a small extent. The noses 19 pass through corresponding openings in the springs 34 and the noses 19 can either be rigidly bonded to the springs 34 (by vulcanising) and the springs 34 are then inserted loosely in the openings 33, or vice versa. It is likewise possible to receive the springs axially in the hub disc by mechanical interengagement, combined with secure vulcanising to the noses of the control elements or a simple plug-in connection between the noses and the elastomer.Figure 8 shows the construction of the noses of the control element 16 which pass through openings 32 in the lining carrier, the openings 32 being made greater in a circumferential direction by the amount of the angle a, ss and the start of the introduction when the clutch plate is subjected to torque is controlled by these angles.

The embodiment by way of example shown in Fig.5 illustrates a clutch plate 3 in which, in contrast to the embodiment of Figure 3, the control element 16 has its noses 19 inserted in the elastomeric spring 34 in openings 33 in the lining carrier, whereas the noses 20 extend into the openings 32 in the hub disc 36. The manner of operation is identical in principle with the one difference that here the friction ring 24 produces the friction torque MR3 and the friction ring 23 produces the friction torque MR2 It is furthermore shown that the elastomeric springs 34 embrace the edges of the openings 33 so that here an axially acting interengagement is provided on insertion of the elastomeric springs.The construction is particularly advantageous when the angles of relative rotation a, ss are chosen to be relatively small in relation to the necessary angular extent of the openings 33 in the lining carrier 8, as in this way the openings 32 in the hub disc 36 can be made short in a circumferential direction so that overall a minimum degree of weakening of the hub disc 36 is caused by these openings 32.

The embodiment by way of example shown in Fig.6 illustrates a clutch plate 4 in which the basic construction of the clutch plate is reversed. This means that the two cover pressings 11 and 12 are connected against relative rotation to the hub 7 in a suitable manner and the lining carrier 10 is provided radially outwards with the friction linings 14 and all together can perform a relative angular rotation with respect to the cover pressings 11 and 12 against the force of the coil springs 13 when subjected to torque.

The damping devices radially within the coil springs are comparable with those of Figures 3 and 5 and they have the same function but are simply slightly different in construction. Thus the control element 16 is arranged so that the noses provided on its radially inner part project into corresponding openings 32 in the lining carrier 10 and the noses 19 provided at its radially outer periphery project into openings 33 in the cover pressing 10 with the interposition of the known elastomeric springs 34. In this embodiment the friction ring 21 provides the basic friction with a torque MR1, the friction ring 24 produces the friction torque MR3 and the friction ring 23 provides the friction torque MR2

Claims

CLAIMS 1. A clutch plate for a friction clutch for motor vehicles comprising a hub with internal splines concentric with an axis of rotation, three disc-like components arranged axially side by side, of which either a central one is secured to the hub and the two outer ones are secured to one another and provided in a radial outer region with friction linings and energy-storing springs between the two kinds of component for mutual relative rotation against the force of the springs or the middle one is connected to the friction linings and the two side ones are arranged to be secured on the hub, further comprising at least two damping devices of which one is in action over the whole range of relative angular movement, and the other is brought into action in dependence on angle and co-operates with a pre-loaded spring device in a parallel arrangement through a control element, which spring device returns the damping device on reversal of the direction of loading, the control element being arranged between the central and one lateral disc-shaped component, in which the control element is arranged radially inside the energy-storing springs and has axially directed noses which engage in corresponding circumferentially larger first openings in one of the disc-shaped components and further axially directed noses which engage in second openings in the other disc-shaped components, with the interposition of a circumferentially acting spring device.
2. A clutch plate according to claim 1, wherein the control element has noses which penetrate directly radially within the energy-storing springs into the central one of the disc-shaped components and is rotationaly connected to this through a pre-loaded spring device and from the one side, if necessary with the interposition of a friction ring, engages against it, and on the opposite side has spaced away from it an axial stop against which a spring abuts, this spring further abuting against a disc-shaped component, if necessary with the interposition of a friction ring, and the control element has noses which are opposite the noses and penetrate through one of the lateral disc-shaped components in an opening with circumferential play and radially within this damping device there is arranged a further damping device which is effective over the whole range of angular movement.
3. A clutch plate according to claim 1, wherein a friction ring for the damping device which is effective over the whole angular range is arranged within the springs and axially substantially in alignment with the central disc-shaped component and one of the lateral ones, and on the opposite side there is arranged an angle-dependent damping device which can be switched from a first damping force to a second damping force comprising two friction rings and a spring arranged between them and a control element.
4. A clutch plate according to claim 3, in which the spring in the form of a plate spring takes care of the entire friction force portion of the damping force.
5. A clutch plate according to claim 4, in which the first damping force is smaller than or equal to the pre-load force of the spring device co-operating with the control element plus the second damping force.
6. A clutch plate according to claim 5, in which the first openings are made in the central disc-shaped component, preferably integrally with windows for the energy-storing springs.
7. A clutch plate according to claim 5, in which the first openings are preferably arranged in the central disc-shaped component.
8. A clutch plate according to either claim 2 or claim 3, in which the pre-loaded spring device is in the form of an elastomeric element in which the noses on the control element engage.
9. A clutch plate according to either claim 6 or claim 7, in which the control element has noses in the region of its outside diameter and its inside diameter, directed axially in respective different directions.
10. A clutch plate substantially as described herein with reference to and as illustrated in Figures 1 and 2 of the accompanying drawings.
11. A clutch plate substantially as described herein with reference to and as illustrated in Figures 3 and 4 of the accompanying drawings.
12. A clutch plate substantially as described herein with reference to and as illustrated in Figure 5 of the accompanying drawings.
13. A clutch plate substantially as described herein with reference to and as illustrated in Figure 6 of the accompanying drawings.
14. A control element which is actuated substantially as described herein with reference to and as illustrated in Figures 7 and 8 of the accompanying drawings.
15. A clutch plate in which build-up of torque and build-up of friction force in accordance with angle of relative rotation occurs substantially as described herein with reference to and as illustrated in Figure 9 of the accompanying drawings.