GB1591949A

GB1591949A - Clutch lining carrier discs

Info

Publication number: GB1591949A
Application number: GB4648177A
Authority: GB
Original assignee: Francaise du Ferodo SA
Current assignee: Valeo SE
Priority date: 1976-11-15
Filing date: 1977-11-08
Publication date: 1981-07-01
Also published as: FR2370893B1; FR2370893A1; IT1116944B; ES464106A1; DE2751043A1

Description

(54) IMPROVEMENTS IN CLUTCH LINING CARRIER DISCS (71) We, SOCIETE ANONYME FRAN CAISE DU FERODO, a French Body Corporate, of 64 Avenue de la Grande-Armee, 75017 Paris, France, 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 lining carrier discs used in friction discs suitable for motor vehicle clutches.

As is well known, friction discs of this kind are essentially composed of a lining carrier disc comprising a generally planar circularly continuous central portion and a peripheral portion divided into radial blades, each of which are connected individually to the central portion by a generally radial foot and extending circumferentially from at least one side of the said foot, and friction linings suitably attached to the radial blades on each face of the lining carrier disc.

In order to impart a certain axial elasticity to the radial blades when subjected to compression, and thus to ensure the most uniform possible distribution of friction between the linings which they carry and the action and reaction plates between which they are gripped when the clutch is engaged, as well as a more uniform rise in temperature during use and therefore reduced wear of the linings and of the plates, a more progressive engagement of the clutch, and advantagepus relieving of the load on the corresponding clutch release pedal when the clutch is released, it is usual to provide the radial blades with folds which circularly delimit in it bearing surface zones which are generally parallel to the plane of the central portion to which each of these blades is connected by a foot, alternating with connection zones which are oblique in relation to the said plane.

The bearing surface zones of the radial blades are alternately in contact with one or the other of the friction linings flanking them, and by means of their connection zones, they permit elastic axial movement of their bearing surface zones between a spaced apart position of rest in which these bearing surface zones are axially offset in relation to one another and therefore in which the corresponding friction linings are axially relatively spaced apart from one another, and a compressed working position in which, through the action of the clutch plates in question the said bearing surface zones are axially less distant from one another, or even in the same plane, and therefore in which the friction linings are axially relatively close to one another.

In previously known constructions of this kind it is usual to find that the radial blades of a lining carrier disc possess along their radially inner edges, that is to say along their edges nearest their feet, a stiffness greater than that which they have along their radially outer edges.

There are two reasons for this; firstly, the folds provided in the radial blades usually extend substantially along the radii of the carrier disc to which the blades belong, and therefore the connection zones of the blades will each have a longer radially outer edge than radially inner edge and hence longer component, lying in the plane containing the central portion of the lining carrier disc, of that radially outer edge. Since it is the extent of these components which inversely determine the stiffness of the respective edge, the radially inner edge of each connection zone will be stiffer than its outer edge. Secondly, in the case where the blades extend circumferentially symmetrically either side of their feet, the stiffness of the blades along their radially inner edges is inevitably increased by the twisting to which their feet are usually subjected, the latter in turn forming the radially inner edges.

However this may be, this difference in stiffness between the radially inner and radially outer edges of a blade leads to a reduction along a radius of the specific crushing load on a friction disc constructed in this manner, this load then being higher along the radially inner edge of this disc than along its radially outer edge.

it is however desirable that this specific load along the radially outer edge of the friction disc should be at least equal to thz load along the radially inner edge of the said disc, in order to obtain radially in opcration the most regular possible heating, and therefore the most regular possible wear.

The present invention secks in a general way to provide an arrangement enabling this aim to be achieved.

According to the invention there is pro vided a lining carrier disc suitable for forming part of friction disc of a clutch, which carrier disc comprises a generally planar, circular, central portion and a peripheral portion divided into radial blades adapted to receive friction linings, each of said radial blades being connected individually to the central portion by a generally radial foot and extending circumferentially from at least one side of the said foot, the said blades having folds which delimit bearing surface zones which are generally parallel to the plane of said central portion the said bearing surface zones alternating with connecting zones which are generally oblique in relation to said ,bear- ing surface zones, wherein the effective number of bearing surface zones disposed along the radially outer edge of each blade are greater than the number of bearing surface zones along the radially inner edge of the corresponding blade, bearing surface zones being provided at both circumferential ends of the radially outer edge of each blade.

The difference Ibetween the number of effective bearing surface zones along the radially inner and outer edges of a blade, which according to a first embodiment is obtained by an inclination of the end folds of the blade defining the circumferentially endmost bearing zones relative to a respective transverse edge of the blade which extends at least in part along a radius of the lining arrier disc or which, as an alternative, is obtained by an inclination of the transverse edges of the circumferentially extending portions of sucb a blade in relation to the corresponding radii of the lining carrier disc, or else by suitably cutting out such a transverse edge, makes it possible in a very simple manner to compensate effectively for the difference in stiffness which the blade would, for the reasons explained above, otherwise have along its circumferential edges.

The invention will now be described, by way of example, with reference to the accompanying diagrammatical drawings, in which : - Figure 1 is a partial view in elevation of a lining carrier disc according to the invention: Figure 2 is a view in axial section thereof along the broken line II-II in Figure 1; Figure 3 shows part of Figure 1 to an enlarged scale; Figures 4 and 5 are respectively flat projections of views in circumferential section on the circular lines IV-IV and V-V in Figure 3; Figures 6, 7, and 8 are views respectively similar to those in Figures 3, 4, and 5, and relate to a modified embodiment; and Figure 9 is a similar view to that shown in Figure 3 and relates to another modified embodiment.

Figures 1 to 5 illustrate the application of the invention to a lining carrier disc having blades each of which extend circum ferentially from each side of their foot portion.

In a manner known per se a disc of this kind comprises a central flat annular portion 10 which is generally circular but which has windows 11 and passages 12 which, since they do not form part of the present invention, will not be described in detail here.

Likewise in a manner known per se, the disc also comprises a peripheral portion divided into radial blades 13, which are each individually connected to the central portion 10 by a generally radial foot portion 14 and each of which in a substantially symmetrical manner extends circularly on each side beyond the foot portion 14.

A blade 13 of this kind is shown separately in Figure 3.

It extends generally between two circumferences C1, C2 which correspond respectively to the radially inner circumferential edge and to the radially outer circumferential edge of the blade, and between two transverse edges T which, in the example illustrated, extend substantially radially.

In the example illustrated the radially outer edge of a blade 13 has a flat 15 in its median zone, but this is not essential.

Furthermore, in the example illustrated, each blade 13 is provided in its central portion with an I-shaped cutout 17, which has on each side two passages 18A, 18B which enable it to receive friction linings on each of its faces, for example by riveting.

Friction linings of this kind are shown diagrammatically by dashed lines at 19A.

19B in Figure 2; the lining carrier disc equipped with friction linings in this manner constitutes a friction disc.

In a manner known per se each blade 13 is provided with folds which circularly delimit bearing surface zones 21A, 21B for contact with the friction linings 19A, 19B respectively, which zones are generally parallel to the middle plane of the central portion 10, alternating with connection zones 22 which are generally oblique in relation to the said plane.

In order to distinguish more clearly between the bearing surface zones 21A, 21B, these zones have been hatched in different directions in Figure 3.

In the Example shown in Figures 1 to 5, on a first side of the central cutout 17 of a blade 13 there are thus in succession, from nearest the central cut-out 17: a bearing surface zone 21A which extends from one of the circumferential edges of the blade to the other and which is circumferentially bounded by, on one side, two elementary folds 23, 23' connecting the circumferential edges of this blade to the corresponding edges of its central cutout 1-7, and on the other side, by a fold 24 connecting the said circumferential edges to one another; a connecting zone 22 circumferentially bounded by, on one side, the aforesaid fold 24 and on the other side, a fold 25 substantially parallel to the fold 24; and a bearing surface zone 21B circumferentially bounded by the single fold 25 and extending as far as the corresponding free end of the blade 13.

On the other side of the central cutout 17 in this blade there are in succession, starting from nearest the cutout 17 and in an arrangement symmetrical to that pre- viously described: a bearing surface zone 21B between folds 23, 23' and 24; a connecting zone 22 between the aforesaid fold 24 and a fold 25; and a bearing surface zone 21A beyond the said fold 25.

In the embodiment illustrated in Figures 1 to 5 the folds 24 and 25, which are substantially parallel to one another, extend obliquely in relation to radii of the disc, along which radii extend the transverse edges T of the circumferentially extending portions of the blade 13 to which they belong.

This has the consequence that if a fold 24 of this kind actually extends from one of the circumferential edges to the other circumferential edge of the blade 13, the fold 25, which is the fold associated with the circumferentially extending portion of a blade at the greatest distance from the foot of the blade, extends only from the radially outer circumferential edge of the blade to the corresponding transverse edge thereof.

Thus, the end bearing surface zones 21A, 21B of the blade 13 do not extend as far as the radially inner circumferential edge of the blade.

In other words, according to a characteristic arrangement of the invention the number of bearing surface zones of a blade 13 which are effective along the circumference C2 selected to correspond to the radially outer circumferential edge of the blade is greater than the number of bearing surface zones effective along the circumference C1 selected to correspond to the radially inner circumferential edge of the blade.

In the embodiment shown in Figures 1 to 5 there are four effective bearing surface zones along the circumference C2, that is to say two bearing surface zones 21A and two bearing surface zones 21B, while there are only two along the circumference C1, namely a bearing surface zone 21A and a bearing surface zone 21B.

This arrangement makes it possible to have along the circumference C2 an axial stiffness at least equal to the stiffness along the circumference C1, despite (in the example illustrated) the unavoidable twisting of the foot 14 which radially connects the flat central portion 10 to an oblique connecting zone 22 of the corresponding blade 13.

Figures 6 to 9 illustrate the application of the invention to a lining carrier in which each blade 13 of the disc does not extend symmetrically from each side of the foot 14 connecting it to the corresponding flat central portion 10.

In the embodiment illustrated in Figures 6 to 8 the transverse edges T of the circumferentially extending portions of the blade extend, as previously, at least partly along radii of tha lining carrier disc.

Likewise as previously, at least that one of the end folds in the at least one of the circumferentially extending portions of a blade of this kind which is at the greatest distance from the foot 14 of the blade (and in practice both these end folds) extends from the radially outer circumferential edge of this blade to the corresponding transverse edge T, obliquely in relation to the radius to which this transverse edge corresponds.

In the example illustrated in Figures 6 to 8 there are thus, on a first side of a bearing surface zone 21A, which is an extension of the flat central portion 10, a first oblique connecting zone -22, a bearing surface zone 21B, a second oblique connecting zone 22, and, a bearing surface zone 21A which is effective only along the circumference C2 corresponding to the radially outer circumferential edge of the blade.

On the other side of the bearing surface zone 21A, an extension of the central portion 10, there are, in succession, in the embodiment illustrated in Figs. 6 to 8: an oblique connection zone 22 and a bearing surface zone 21B which Is effective only along the circumference C2.

In the further modified embodiment illustrated in Figure 9, for at least one of the circumferentially extending portions of a blade 13, the transverse edge T of the latter is partly composed of a portion Tl which extends substantially along a radius of the lining carrier disc, near the radially outer circumferential edge of the blade, and partly of a portion T2 which extends generally obliquely in relation to the said radius and which therefore moves away from the latter.

In this case, as illustrated, the end bearing surface zone of the corresponding circumfercntially extending portion of a blade of this kind is effective only along the cir cumference C2 corresponding to the radially outer circumferential edge of the said blade, even if the fold 25 which delimits it extends substantially parallel to the radius corresponding to the portion T1 of the transverse edge T in question.

Thus, as previously, the stiffness of a blade of this kind along its radially outer circumferential edge is at least equal to its stiffness along its radially inner circumferential edge.

In the embodiment shown in solid lines T2 in Figure 9 the portion T2 of the trans vcrse edge T which moves away from the corresponding radius is generally rectilinear.

A result similar to that described can be obtained by giving the portion T2 a curved shape by cutting out part of the circumferentially extending blade portion in question, as shown by a dashed line T'2 in Figure 9, for example.

In fact, in both cases the portion of the transverse edge extends away from the end radius of the blade, and since it extends obliquely in relation to that radius it eliminates along the radially inner circumferential edge of the blade the effective bearing surface zone, which is present along the radially outer circumferential edge of the blade.

The invention is not limited to the em bodimcnts described and illustrated but includes any alternative construction and/or combination of their various elements within the scope of the appended claims.

As will be understood, the passages 18A, 18B of a blade 13 which enable the latter to be fitted in turn with its friction linings 19A, 19B associated with it are suitably disposed respectively in bearing surface zones 21A, 21B of the blade.

WHAT WE CLAIM IS: 1. A lining carrier disc suitable for forming part of a friction disc of a clutch, which carrier disc comprises a generally planar, circular, central portion and a peripheral portion divided into radial blades adapted to receive friction linings, each of said radial blades being connected individually to the central portion by a generally radial foot and extending circumferentially from at least one side of the said foot, the said blades having folds which delimit bearing surface zones which are generally parallel to the plane of said central portion, the said bearing surface zones alternating with connecting zones which are generally oblique in relation to said bearing surface zones, wherein the effective number of bearing surface zones disposed along the radially outer edge of each blade are greater than the number of bearing surface zones along the radially inner edge of the corresponding blade, bearing surface zones being provided at both circumferential ends of the radially outer edge of each blade.

2. A lining carrier disc as claimed in Claim 1, wherein at least one of the folds defining the circumferentially endmost bearing surface zones of each blade extends from the radially outer edge of the blade to an adjacent transverse edge thereof.

3. A lining carrier disc as claimed In Claim 2, at least one transverse edge of each blade extending at least partly substantially radially, wherein the corresponding end fold of the blade extends obliquely in relation to the substantially radial part of the transverse edge.

4. A lining carrier disc as claimed in Claim 2, one of the end folds of each blade extends substantially radially of the said disc, wherein at least part of the transverse edge corresponding to said end fold extends obliquely relative to said substantially radial end fold.

5. A lining carrier disc as claimed in Claim 4, wherein the part of the transverse edge which extends obliquely is generally rectilinear.

6. A lining carrier disc as claimed in Claim 4, wherein the part of the transverse edge which extends obliquely is formed by a cutout in the transverse edge of the blade.

7. A lining carrier disc substantially as hereinbefore described with reference to Figs. 1 to 5, Figs. 6 to 8, or Fig. 9 of the accompanying drawings.

8. A clutch friction disc, incorporating a lining carrier disc as claimed in any of

Claims

Claims 1 to 7.