GB2201486A

GB2201486A - Clutch disc assembly

Info

Publication number: GB2201486A
Application number: GB08804184A
Authority: GB
Inventors: Karl Heinz Werner
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1987-02-25
Filing date: 1988-02-23
Publication date: 1988-09-01
Anticipated expiration: 2008-02-23
Also published as: FR2611243A1; DE3706027C2; DE3706027A1; GB8804184D0; FR2611243B1; GB2201486B

Abstract

To narrow the tolerance in friction force generation in the case of a clutch disc assembly, it is proposed that the radially inner zones of the cover plates 5, 7, which are initially tensioned in an axial direction as friction force generating parts and which bear on the hub disc 4 be so influenced in their spring characteristics by the provision of corresponding apertures 13, that the tolerances in the generation of axial pre-tensioning force have a less unfavourable effect on the friction force. <IMAGE>

Description

TITLE: Clutch disc assembly The invention relates to a clutch discZwieh aY torsion vibration damper. A clutch disc of simple construction is knows for example from DE-PS 1 272 645. The clutch disc assembly has a torsion vibration damper and consists of a hub with a hub disc, cover plates disposed on both sides and of which one is constructed as or-is connected to a lining carrier, spacing rivets for rigid connection of the cover plates. to one another as well as to main- tain a specific gap. Springs between hub disc and cover plates in suitable ports to provide torsion springing under torque loading, and-means of generating friction force in which the radially inner areas of the cover plates bear under their inherent tension on an annular zone of the hub disc.

Where these clutch discb/are concerned, the friction force for assisting the damping of the torsion vibrations is generated in that the cover plates disposed on both sides of the hub disc generate a friction force in relation to the hub disc by virtue of a corresponding initial tension in an axial direction.- For this purpose, the hub disc is provided on both sides with an annular surface zone on which the cover plates bear. The axial initial tension is achieved in that the spacing rivets have their length matched to the hub disc.

Well, as the cover plates- have to be of relatively rigid=construc- tion on the one hand in order to be able to transmit high torque levels and since on the other the tolerances in the width of the hub disc andin the length of the spacing rivets cannot be kept particularly close without substantial expenditure, quite considerable fluctuations in friction force occur under practical conditions.

The object of the present invention is to minimise the effects of the tolerances on the friction force by adopting the simplest possible measures.

According to the invention, this problem is resolved by the characterising part of the main claim - by making the apertures according to the invention in the side plates (cover plates), it is possible to reduce quite considerably the spring stiffness in this area, so that without restricting the tolerances, the fluctuations in friction force can be reduced to an equal extent.

It has been demonstrated that by these simple measures, it is possible to reduce the stiffness of the springing to a half that previously available.

Advantageously, the apertures are disposed around the periphery, between the ports for the springs. Thus it is possible, in a radial direction, to be relatively independent of the disposition of the ports for the springs.

The apertures provided in the side plates (cover plates) can thereby vary in their geometrical form. Advantageously and easily produced are circular apertures or substantially triangular apertures. With triangular apertures, one point of the triangle is directed radially outwardly so that in this way the material between two ports which are disposed beside each other in a peripheral direction remains unweakened.

It goes without saying that it is also possible, instead of circular or triangular apertures, to provide relieving slots.

Where Where constructions of a clutch disc are co cerned, in which on the one hand a side plate (cover plate) is connected to a separate lining carrier which is disposed on the inside of the cover plate, the above mentioned apertures are-made directly into the lining carrier, so that this participates in the generation of friction force, by reason of its axial initial tension.

The invention will be described in greater detail hereinafter with reference to examples of embodiment which are shown in the accompanying drawings which, in detail,show: Fig. 1 a cross-section through a clutch disc assembly with a cover plate as a lining carrier; Fig. 2 shows a cross-section through a clutch dise}t blaYsepa- rate lining carrier on the inside of one of the cover plates and Fig. 3 is a side view of the lining carrier shown in Fig. 2.

Fig. 1 shows the cross-section through a clutch disc assembly 1 with a simple torsion vibration damper. The clutch disa7iemcbolfrises a hub 3 with a radially outwardly pointing hub disc 4. On both sides of the hub disc 4 there are side plates (cover plates) 5, 7, of which the cover plate 7 is at the same time constructed as a lining carrier and carries on its outer periphery friction linings 15. Both cover plates 5 and 7 are rigidly connected to each other via spacing rivets 9 which maintain them at a distance from each other. In corresponding ports both in the hub disc 4 and -also in the cover plates 5 and 7, there are coil springs 10 which transmit the torque resiliently and in torsionally elastic fashion.The length of the spacing rivets 9 is such that the radially inner zones of the cover plates 5 and 7 bear with axial initial tension on the hub disc 4 in an axially opposite situation, in fact in each case in an annular surface zone 12 which is directly adjacent the region of the hub 3.

When torque is applied, the two cover plates 5 and 7 are, against the force of the springs 10, rotated in respect of the hub 3 and the hub disc 4, so that friction is generated by the cover plates 5 and 7 which are applied with an axial initial tension against the annular surface zones 12. At least in one of the two cover plates 5 and 7, now, in the area radially outside the annular surface zones 12and preferably in the peripheral zone between successive ports for springs 10, there are apertures 13. The aperture 13 serves to reduce the spring rating in this area to a markedly lower level, so the fluctuations in the tolerances firstly in terms of the length of the spacing rivets 9 and on the other with regard to the width of the hub disc 4 in the region of the annular surface zone 12 are of correspondingly reduced effect as friction force fluctuations.As a result of the measures described here, it is possible to reduce the spring stiffness to about one half the level which would exist without these apertures. Thus it is possible for the same tolerances also to reduce the fluctuations in friction force by half.

Fig. 2 shows a clutch disc75 witt a somewhat modified construction. The hub 3 comprises a hub disc 4 with two annular surface zones 12 against which the side plates (cover plates) bear. On one side of the hub disc 4 there is a conventional cover plate 5 while on the other side there is a cover plate 6 which has its radially inner zone maintained at a distance from the annular zone 12 of the hub disc 4. The cover plate 6 is on its inside face connected to a separate annular disc-shaped lining carrier 8 which, in its radially outer area, carries the friction linings 15 while its radially inner area bears with axial initial tension on the corresponding annular surface zone 12 of the hub disc 4.

The initial tension is generated by a corresponding matching of the length of the spacing rivets 9 to the width of the hub disc 4 in the region of the annular surface zones 12. The construction chosen here, with a cover plate 6 and a separate lining carrier 8, is conducive to the all-in-all stiffer construction assembly of the clutch disc/4 and with regard to the invention it is significant in so far as the generation of friction force on the side of the cover plate 6 is taken over by the lining carrier 8.

The side view of the lining carrier 8 is reproduced in Fig. 3.

It has on its outer periphery, although they are not designated in greater detail, areastwhich receive the friction linings 15, and also a plurality of peripherally distributed ports 11 to receive springs 10 and, disposed peripherally between these ports 11 and in a radial direction outside the annular surface zone 12 of the hub disc 4 apertures 13, which quite considerably reduces the spring rating of the lining carrier 8 in the inner area when an axial force is applied. The lowering of the spring rating can amount to half that of the continuous, i.e. uninterrupted, lining carrier. In consequence, with the tolerance otherwise unaltered, it is possible likewise to halve the friction force fluctuations.

The apertures 13 have, as Fig. 3 shows, a circular form. In Fig.

3, the broken lines indicate alternative forms of aperture. In particular, triangular apertures 14 are suitable, having one corner pointing radially outwardly, or in particular T-shaped slots 16. The aforedescribed forms of aperture may also be provided in the case of the clutch disSc7fmkhgwn in Fig. 1.

Claims

CLAIMS:

1. Clutch disc assembly comprising a hub (3)having a radially projecting hub disc (4), two annular disc-shaped- side plates (5, 7; 5, 6, 8) disposed on axially opposite sides of the hub disc (3) and connected rigidly to each other to form one unit by spac ing rivets (19) with a predetermined gap and mounted to rotate on and relative to the hub (3) as one unit, and with clutch friction linings (15) -connected to the side plate unit, and comprising a plurality of springs (10) disposed in axially corresponding ports in the hub disc (3) and the side plates (5, 7; 5, 6, 8) and which couple the hub disc (4) and the side plate unit together in torsionally elastic manner, and compris ing, on the hub (3) and on both sides of the hub disc (4), axial annular surface zones (12) on which the side plates (5, 7; 5, 8) bear resiliently under axial initial tension in order to damp friction from rotary oscillations in the region of their inner periphery, characterised in that at least one of the side plates (5i 7; 8) is provided with apertures (13, 14,

16) to flatten out the inherent tension spring characteristic radially outsie the annular surface zones (12) of the hub (3).

2. Clutch disc/accorYding to Claim 1. characterised in that the apertures (13, 14, 16) are in a peripheral direction provided between the ports which contain the springs (10).

3. Clutch diseqaccorxing to Claim 1 or 2, characterised in that the apertures (13) have a circular contour.

4. Clutch disc assembly according to Claim 1 or 2, characterised in that the apertures (14) have a triangular contour.

5. Clutch disc according to Claim 4, characterised in that the apertures (14) have afle corner of their contour pointing radially outwardly.

assembly

6. Clutch disc/according to Claim 1 or 2, characterised in that the apertures are constructed as slots (16).

7. Clutch disc assembly according to at least one of Claims 1 to 6, charac- terisedin that one of the side plates is constructed as a lining carrier disc (8) which carries the clutch friction lin ings (15.) and which extends in one piece radially and contin uously, extending as far as one of the annular surface zones (12) and bearing under inherent tension axially and resiliently on the annular surface zone (12).

assembly

8. Clutch disc/according to Claim 7, characterised in that on that side of the lining carrier plate (8) which is axially re mote from the hub disc (4) there is a third annular disc shaped side plate (6) which is rigidly connected by spacing rivets (19) to the side plate unit and which comprises ports which correspond axially to the ports of the hub disc (4) and the two other side plates (5, 8) and in that the third side plate (6) extends at least in its annular surface zone (12) at an axial distance from the lining carrier plate (8).

9. Clutch disc assembly substantially as described with reference t9 Figure 1 or Figures 2 and 3 of the accompanying drawings.