GB2309503A

GB2309503A - Pre-damper for a clutch plate

Info

Publication number: GB2309503A
Application number: GB9701151A
Authority: GB
Inventors: Jurgen Kleifges; Ernst Muller; Werner Wiesner
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Friedrichshafen AG
Priority date: 1996-01-23
Filing date: 1997-01-21
Publication date: 1997-07-30
Anticipated expiration: 2017-01-21
Also published as: ES2142212B1; GB9701151D0; BR9700735A; ES2142212A1; FR2743854B1; GB2309503B; FR2743854A1; DE19602221C1

Description

2309503 1 PRE-DAMPER FOR A CLUTCH PLATE The invention relates to a

pre-damper for a clutch plate of a motor vehicle friction clutch of the kind comprising two axially spaced rings connected for rotation together, a disc arranged between the two rings and at least one spring received in superimposed windows in the rings and the disc, the rings being connected by one or more axially projecting lugs on one ring engaging in corresponding notches in the other ring.

Such a pre-damper is known from WO 95124 573 and is designed to damp vibrations which arise through unavoidable uneven running of an internal combustion engine on operation at low torque, for example on idling. The residual torque at the hub of the clutch in this state of operation is very small so that the movement of side discs of a main vibration damper cannot be damped as the main damper spring forces are greater than the forces of the vibrations. These forces are transmitted from the side discs into the pre-damper and damped by the pre-damper springs, which have low spring forces. As the torque rises the predamper rotates with the hub disc and the vibrations are then damped by the main damper.

To reduce the assembly costs of a clutch as much as possible subassemblies are formed and assembled together subsequently. In the clutch plate the pre-damper is often such a sub-assembly. Securing means must be provided to locate the two rings axially so that the pre-damper does not fall apart when it is handled. In the known pre-damper this location is achieved through radially outwardly projecting lugs on one ring which are bent to lie axially and are received in the corresponding notches in the other ring. These lugs are further bent over at their axial outer ends so as to form a nose by which the ring can be snapped behind the notch. The 2 bending operations can be performed before or after assembly of the predamper. As it is only necessary to prevent falling apart during handling, no great forces have to be transmitted by the bent lugs.

DE-A-38 05 595 and DE-A-38 10 922 show clutch plates in which the pre-assembled pre-damper is secured for handling in that the lugs on the one ring have hook-shaped resilient ends which engage in or behind corresponding notches on the other ring.

According to the present invention, in a pre-damper for a clutch plate of a motor vehicle friction clutch of the kind set forth, each lug and corresponding notch are connected by a staking process.

This provides a different type of securing means, in which the pre- damper sub-assembly is secured for handling in a particularly simple way.

Further, the lugs do not have to be deformed twice, so that their stability is maintained. The construction also enables the lugs to transmit torque.

Accordingly, for the same constructional design either a greater torque can be transmitted or, for the same torque transmitted, the thickness of the material can be reduced, which leads to an overall reduction in cost and weight.

Advantageously the notches are deeper than the thickness of the material of the lugs, and the material at the side edges of the notches is staked so that the staked material projects beyond the corresponding edges of the lugs.

In another embodiment the lugs are staked after insertion in the notches to spread out the material of the lugs. For this purpose, a pointed stamp of a press tool is applied to the lug so that the displaced material is 3 urged towards the edges of the notch. Alternatively, the size of the notches can be reduced after insertion of the lugs, for example by a press tool acting on the material at the edges of the notch.

is Some embodiments of the invention are illustrated by way of example in the accompanying drawings, in which:- Figure 1 shows part of a clutch plate in longitudinal section with a pre- assembled pre-damper; Figure 2 shows the pre-assembled pre-damper of Figure 1; Figure 3 shows a first embodiment of the connection of the predamper parts; and Figure 4 shows a second embodiment.

Figure 1 shows a clutch plate for a motor vehicle friction clutch, omitting components not necessary for a description of the invention. The clutch plate has a hub 2 provided with splines 3 for connection to a shaft (not shown). The hub 2 mounts a radially outwardly extending hub disc 4 and cover pressings 1 and 12 provided one on each side of the hub disc 4 and coaxial with it. The cover pressings 1, 12 are connected together to rotate together through rivets (not shown). One cover pressing 12 carries friction linings, only part of which are shown. The hub disc 4 and the cover pressings 1, 12 have respective windows 14, 16, 13 for receiving compression springs. The springs acts as a main damper of torsional vibrations arising in the clutch plate.

4 A pre-damper for damping vibrations arising at low torque, such as during idling of the motor vehicle engine, before the main damper operates. The pre-damper is provided between the cover pressing 1 and the hub disc 4. The pre-damper comprises two rings, a follower disc 5 and a cover pressing 7, an intermediate disc 8 arranged between the rings and compression springs 10. The follower disc 5, the cover pressing 7 and the intermediate disc 8 each have circumferentially spaced windows 15, 17, 18 respectively, the windows being aligned axially. A spring 10 is then arranged in each set of windows 15, 17, 18, in order to damp 10 relative movement of the disc 5, cover pressing 7 and disc 8.

In a modification (not shown) the pre-damper is arranged between the cover pressing 12 and the hub disc 4, in mirror image.

is The radially outer ends of the follower disc 5 are bent axially to form lugs 6. A number of lugs 6 are provided, spaced around the periphery of the disc 5. A corresponding number of notches 9 are formed in the cover pressing 7, similarly spaced around the periphery. As can be seen in Figure 3, the depth of the notches 9 is greater than the thickness of the material of the lugs 6.

To assemble the pre-damper first the compression springs 10 are inserted in the windows 15 in the follower disc 5, then the intermediate disc 8 is placed in position with the windows 18 over the springs 10, and finally the cover pressing 7 is put in position with the windows 17 over the compression springs 10. To secure the parts together, to prevent loss of the springs 10, a stamp tool 20 of a press tool (not shown) is used in a staking process, to stake the material at the side edges 9' of the notches 9, so that the material projects beyond the edges of the lugs 6. This ensures that the lugs 6 are secured in the notches 9, and connects the disc 5 and cover pressing 7 for rotation together. The connection also serves to transmit torque.

Figure 4 shows a modification of the staking process. Here, after assembly of the pre-damper a tool 30 of a press tool (not shown) provided with a point 31 is applied to the lugs 6 in the notches 9 so that the material of each lug 6 is spread out and displaced towards the side edges of the notch 9. Here it can be of advantage for the thickness of the lugs 6 to be greater than the depth of the notches 9.

In another modification of the staking operation, the process of Figure 4 is inverted, and the size of the notches 9 is reduced by staking the material at the side edges 9', to form the connection between the lugs 6 and notches 2.

is 6

Claims

1. A pre-damper for a clutch plate of a motor vehicle friction clutch of the kind set forth, in which each lug and corresponding notch are 5 connected by a staking process.

2. A pre-damper as claimed in claim 1, in which the notches are deeper than the thickness of the material of the lugs, and the material at the side edges of the notches is staked so that the staked material projects 10 beyond the corresponding edges of the lugs.

3. A pre-damper as claimed in claim 1, in which the lugs are staked after insertion in the notches to spread out the material of the lugs.

4. A pre-damper as claimed in claim 1, in which the size of the notches is reduced after insertion of the lugs.

5. A pre-damper for a clutch plate of a motor vehicle friction clutch of the kind set forth substantially as described herein with reference to and as illustrated in Figures 1 to 3 of the accompanying drawings.

6. A pre-damper for a clutch plate of a motor vehicle friction clutch of the kind set forth substantially as described herein with reference to and as illustrated in Figure 4 of the accompanying drawings.