EP2089635A2

EP2089635A2 - Clutch friction disk

Info

Publication number: EP2089635A2
Application number: EP07866524A
Authority: EP
Inventors: Philippe Walter; Pascal Moreau; Loïc ADAMCZAK; Jean-Jacques Chatras
Original assignee: Valeo Materiaux de Friction SAS
Current assignee: Valeo Materiaux de Friction SAS
Priority date: 2006-10-30
Filing date: 2007-10-30
Publication date: 2009-08-19
Also published as: WO2008053126A3; BRPI0717792A2; WO2008053126A2; MX2009004795A; FR2907864A1; CN101529109A; KR20090074065A

Abstract

The invention relates to a dry-clutch friction disk comprising a web (2), at least one friction lining (3) and an intermediate part (6), wherein said intermediate part (6) comprises a crown (61) from which tabs (62, 63) extend radially towards the outside, the web (2) comprising progressive areas and the radially extending tabs (62, 63) of the intermediate part (6) being axially arranged opposite said progressive areas, a tab (62, 63) being systematically interleaved between the web (2) and the lining(s) (3). The invention also relates to a method for making such a friction disk.

Description

FRICTION DISC CLUTCH

The present invention relates to a dry clutch friction disc, in particular for a motor vehicle. In the usual manner, a clutch friction disk is intended to be mounted on a shaft said led being inserted between a reaction plate and a pressure plate of a clutch integral in rotation with a shaft said to drive. During a clutch operation, said pressure plate clamps the friction disk against said reaction plate.

Although applicable to any type of friction disc, the invention is of particular interest for a so-called progressive clutch friction disc. A progressive clutch friction disk, as for example represented in FIGS. 7 and 8 of patent FR 1 304 067, comprises a substantially flat ring-shaped metal support, commonly referred to as "the web", the outer periphery of which is fragmented by so as to have fins attached to, or reported on, said ring.

These fins are alternately folded so as to include staggered portions, on either side of a mean plane, capable of being deformed elastically under the effect of a clamping force.

A crown-shaped friction liner is attached to each side of said support by being secured by any suitable means to some of said offset portions. During tightening, the fins deform elastically, the offset portions coming closer to each other.

This results in a progressive effect in the clamping of the friction disk and therefore in the transmission of the torque during a clutch maneuver, which allows to considerably reduce the jolts. In order to increase their elasticity, said fins have cutouts and openings.

In operation, the friction linings are subjected to a significant heating that can reduce the surface hardness. Under the effect of the clamping force to which the linings are subjected, the latter are then frequently subject to a phenomenon of incrustation of said fins in the linings, which causes a loss of elasticity and therefore progressivity. It has already been proposed to avoid this disadvantage to interpose an annular spacer, in particular a strip or steel foil glued to each lining between the liner and said fins. Such an arrangement which is visible in Figures 7 and 8 of the aforementioned French Patent 1 304 067, gives satisfaction.

It is found that such an arrangement, although advantageous in terms of resistance to encrustation, leads to increase the inertia of the friction disc. This results in less flexibility of the transmission chain particularly sensitive during the coupling and uncoupling phases of the clutch.

Another proposal, as described in the patent application FR 2 817 002 of the applicant, consists in alternating between the web and the liners, at least one of the liners having areas of reduced thickness,

- The interposition of legs of an intermediate piece comprising a ring from which legs extend radially towards the outside, these lugs interposing axially in areas between the veil and the or lining (s), and

- The juxtaposition of the veil and areas of reduced thickness of gaskets.

The disadvantage of this latter solution is the difficult industrial realization of at least one lining having areas of reduced thickness.

The object of the present invention is to overcome the above drawbacks and to provide a friction disc with low addition of inertia and resistant to incrustation phenomena. This object is achieved by a dry clutch friction disc comprising a web, at least one friction lining and an intermediate part, said intermediate part comprising a ring from which tabs extend radially outwards, the web comprising progressivity zones, the lugs of the radially extending intermediate part being arranged axially facing said progressivity zones, a lug systematically interposing between the web and the (or) lining (s).

Thus, according to the invention, all areas of the web which are in contact with a lining are by means of tabs, that is to say by indirect contact veil - lug - lining, no direct contact being possible. possible between the veil and the (or) fittings.

This results in a significant decrease in the inertia of the friction disk compared to that of a friction disk comprising an annular spacer, and a significant decrease in the incrustation in the linings, while having known type fittings, namely of substantially constant thickness, achievable commonly industrial.

The inventors have found that for most sails, especially in the case of sail including progressivity zones, the risks of incrustation are not evenly distributed over the surface of the lining. An intermediate piece according to the invention is advantageously arranged in a clutch disk so that the radially extending lugs are disposed in contact with all the areas of the friction linings where the risk of incrustation is greatest. These zones correspond in particular to the areas where the pressure exerted by the web on the lining is highest during the coupling phases of the friction disk against the reaction plate. The inventors have further found that the presence of free space between the tabs of the insert is particularly advantageous. They have noticed that under the pressure of the areas where the pressure is highest, the material of the friction lining can flow.

This creep in the zones of greater pressure can lead to deformations of the intermediate part when using an annular spacer piece of the state of the art. Thanks to the particular shape of the intermediate piece according to the invention which leads to spare spaces between the legs, the material can flow in these free spaces and thus prevent deformation of the insert.

According to one embodiment, the insert is formed from a sheet. This sheet is generally thin.

The friction pad (s) and the part interlayer above are generally assembled by gluing.

According to one embodiment, the (or) friction lining (s) and the insert part are substantially radially in internal and external circles of the same diameters.

According to embodiments of the friction disc according to the invention, taken separately or in combination:

the zones of progressivity comprise fins capable of axial elastic deformations;

the veil comprising the fins is cut and formed in a sheet; the fins are attached to a sheet previously cut and formed to form the veil. The invention also relates to a method of manufacturing a dry clutch friction disk according to the invention, as described above and comprising a web with progressivity zones, at least one friction lining and an intermediate piece where the following components are supplied: the web, the friction lining (s), the intermediate part (s);

- Assembling said components by rivets so that the tabs of the intermediate piece are arranged axially facing all areas of progressivity of the web.

According to one embodiment of said method, the friction lining and the intermediate part are preassembled in the form of a friction member. The mounting of the friction disk is then facilitated.

According to another embodiment of said method, the components are assembled by rivets only one of which end is supported on counter faces of the (the) friction linings. It is thus possible to avoid the use of glue in the assembly and to obtain an advantageous disk in terms of cost. The term "assemble by rivets only", an assembly where the rivets are only active in the transfer of forces between components of the assembly, thus excluding components are glued together.

The term "facing surfaces of the friction lining" means surfaces adapted to receive a rivet head, including substantially flat or conical surfaces, in contact with which one can have a rivet head, in particular respectively flat or conical. These countersink surfaces are obtained by milling the lining so as to create a bore with a small diameter portion in which the rivet body can move and a larger diameter portion of which one end comprises the countersink surface to receive the rivet head. The larger diameter portion is milled so that the rivet head is embedded in the packing when new. After crimping the rivet, most of the countersink surface is in contact with most of the bearing surface of the rivet head.

It has been demonstrated that such friction discs are particularly well suited for applications to clutches coupled to diesel engines, in which the load on the plate, and thus the pressure on the linings, are high.

It has been shown that such friction discs respond successfully to the centrifugation constraints of such applications and that thanks to the moderate inertia of these discs, the shifts are flexible. The invention will be detailed hereinafter with the aid of non-limiting examples illustrated by the following figures:

Figure 1: schematic drawing of a friction disc;

- Figure 2: schematic view of the insert of the friction disc according to the invention;

- Figure 3a: schematic sectional view along A-A of components before mounting a friction disc according to the invention;

- Figure 3b: schematic sectional view along A-A of assembled components of a friction disc according to the invention;

- Figure 4: schematic sectional view along B-B of assembled components of a friction disc according to

The invention.

For reasons of clarity, the dimensions of the various elements shown in these figures are not in proportion to their actual dimensions. In all the figures, identical references correspond to identical elements.

In the context of the invention, the terms "axial", "axially" and "radial", "radially" are defined in relation to the axis of rotation of the friction disk. "Axial" is understood to mean a direction parallel to this axis of rotation and "radial" is understood to mean a direction perpendicular to this axis and passing through this axis.

The term "inside" an area close to this axis of rotation and "outside", an area away radially from this axis of rotation.

FIG. 1 represents a schematic front view a friction disk 1 comprising a hub 5 capable of being secured to a driven shaft, a friction lining 3 and dashed a web 2. Elastic means, including springs 4, are arranged to allow the damping and / or vibration filtration of the shaft leading to the driven shaft.

FIG. 2 shows a view of the intermediate part 6. This part comprises a ring 61 of inner radius close to the inside radius of the friction lining 3. Tabs 62, 63 extend radially outwardly from this ring 61. These lugs 62, 63 preferably extend to a limit constituted by the outer radius of the friction lining 3. According to one embodiment, the radial width of the ring 61 is less than or equal to 20% of the total radial width of the intermediate part 6, considered between the inner radius of this part and the radial extension of the outermost legs. According to one embodiment, the zones of the tabs 62, 63 connected to the ring 61 occupy circumferentially less than 50% of the outer circumference of said ring 61.

The tabs 62, 63 shown are substantially rectangular. They could also have a flared shape, for example wider outward than inward.

The tabs 62 comprise openings 64 capable of passing a rivet body but not its head. The legs 63 are full.

Figure 3 shows a section along AA of Figure 1, a friction disc according to the invention, wherein the components appear arranged before mounting in Figure 3a and after mounting in Figure 3b. A spacer 6 is disposed on each side of the web 2, between said web and a gasket 3. The gasket comprises countersunk holes with a portion 32 large enough to accommodate a rivet head 7 and a narrower portion 33 to allow movement of the rivet body without allow passage of the rivet head. At the bottom of the widest part 32 is a counter-face 31 on which the rivet head can be supported. The part of the insert 6 intended to be in contact with the area of the hole 33 of the lining also comprises a hole 64 of the same diameter, as well as the web 2 which comprises a hole 21. The lining 3 located on the other side of the web 2 comprises a hole 34 capable of passing a rivet head. A rivet 7 is crimped to secure the lining 3, the insert 6 and the veil 2 by placing a head of this rivet on one side in contact with the facing face 31 and placing the other head of the rivet in the veil , the body of the rivet passing through the holes 33, 64, 21. The intermediate part 6 may be previously glued to the friction lining 3.

After assembly, a distance e between the two intermediate parts results from the presence of progressive areas in the web, in particular in the form of axially elastically deformable fins. Such fins appear in dashed lines in FIG. 1 and are presented in section in FIGS. 3 and 4.

In this case, the fins are attached to a sheet previously cut and formed to form the web 2. Figure 4 shows a schematic section, according to BB of Figure 1, the same friction disc as shown in Figure 3. We see easily that the web 2 comprises fins some of which is in sliding contact with a tab 63 of the first intermediate part 6, a second part is fixed to a perforated tab 62 of the second intermediate part 6, a third part to a perforated tab 62 of the first intermediate part 6 and a fourth part is in sliding contact with a lug 63 of the second intermediate part 6. As a result, according to this view, a corrugated shape of this area of the veil which ensures the progressivity of the friction disc. In addition, according to the invention, all areas of the web 2 in contact with the liners are by means of lugs 62 or 63.

The invention is not limited to these types of embodiments and must be interpreted in a nonlimiting manner and encompassing any equivalent embodiment.

Claims

A dry clutch friction disc comprising a web (2), at least one friction lining (3) and an intermediate part (6), said intermediate part (6) comprising a ring (61) from which tabs (62, 63) extend radially outwardly, the veil

(2) comprising progressiveness zones, the tabs (62, 63) of the radially extending intermediate piece (6) being arranged axially facing said progressivity zones, a tab (62, 63) systematically interposed between the sail (2) and the (or) trim (s) (3).

2. friction disc according to the preceding claim according to the preceding claim such that the insert (6) is formed from a sheet.

3. dry clutch friction disc comprising according to one of the preceding claims, such that the (or) friction lining (s) (3) and the intermediate part (6) are assembled by gluing.

4. Friction disc according to the preceding claim such that the (or) friction lining (s)

(3) and the insert (6) are substantially radially inscribed in inner and outer circles of the same diameter.

5. Friction disc according to one of the preceding claims such that the progressivity zones comprise fins capable of axial elastic deformations.

6. Clutch friction disc according to the preceding claim such that the web (2) comprising the fins is cut and formed in a sheet.

7. clutch friction disk according to claim 5 such that the fins are attached to a sheet previously cut and formed to form the web (2).

8. A method of manufacturing a dry clutch friction disc according to one of the preceding claims characterized in that:

the following components are supplied: the web (2), the friction lining (s) (3), the intermediate part (s) (6), and

- Assembling said components by rivets (7) so that the tabs (62, 63) of the intermediate piece (6) are arranged axially facing all areas of progressivity of the web (2).

9. Manufacturing process according to the preceding claim such that the friction lining (3) and the intermediate part (6) are pre-assembled in the form of a friction member.

10. The manufacturing method according to the preceding claim such that the components are assembled by only rivets (7), one end of which bears against the facing faces (31) of the (the) friction linings (3).