GB2303672A

GB2303672A - Fixing a friction element to a spring segment of a clutch disc

Info

Publication number: GB2303672A
Application number: GB9615538A
Authority: GB
Inventors: Dieter Pretzel; Martin Kunz
Original assignee: LuK Lamellen und Kupplungsbau GmbH
Current assignee: LuK Lamellen und Kupplungsbau GmbH
Priority date: 1995-07-27
Filing date: 1996-07-24
Publication date: 1997-02-26
Anticipated expiration: 2016-07-24
Also published as: ITMI961601A0; GB9615538D0; ITMI961601A1; FR2737270A1; BR9603192A; IT1283341B1; DE19626686A1; FR2737270B1; DE19626686B4; GB2303672B

Abstract

A friction element, consisting of a support 2 and a friction lining 3, is fixed to a spring segment 5 of a clutch disc by using holders 13, 14 to clamp the segment and support together (figure 4a), using a ram 16 to force material of the support by deformation axially through an aperture in the segment so that a hollow attachment (18, figures 4b and 4c) is formed, and using a ram 15 to force the free end of the attachment protruding on the side of the segment remote from the support around the edge of the aperture in the segment in the manner of a rivet head.

Description

Fixing a friction element The invention relates to a method for fixing a friction element, consisting of a support and a friction lining fixed thereon, onto a carrier by means of at least one rivet-type connection. Furthermore the invention relates to clutch discs having friction elements of this kind wherein these friction elements can be fixed on so-called lining spring segments which serve as carriers.

Friction elements or clutch discs of the kind previously mentioned are known for example through DE-PS 30 47 934, GB PS 20 19 959 and FR-OS 2 568 964.

In the designs according to DE-PS 30 47 934 the connection between a friction element and the spring segment supporting same is produced by means of separate rivet elements. A connection of this kind is comparatively costly since the rivet elements have to be prepared separately and thus incur storage and administration costs as well as furthermore additional assembly expenditure.

From the description of FR PS 2 568 964 it is apparent that to produce the rivet-type connections shown in Figures 2 and 3 the support plates 2 already have moulded-on tubular projections which form hollow rivets. These tubular projections are as shown in Figures 2 and 3 flanged over in order to form closing heads. Tubular projections of this kind however have the drawback that when preparing the individual support plates or friction elements these can become hooked or where these support plates are prepared stacked for assembly they require additional space since the individual plates are kept at a certain distance apart owing to the tubular projections.

The object of the present invention is to overcome the aforesaid disadvantages and to allow a particularly simple and cost-effective connection between a friction element and a support element of the kind mentioned at the beginning.

Furthermore the invention is also to allow a particularly simple construction of clutch discs whereby the assembly thereof is to be optimized.

According to the invention this is achieved in that in order to produce the connection between a friction element and a carrier of the kind mentioned at the beginning the carrier has at least one recess and this connection is made by placing the carrier and support at least partially one above the other whereupon the material of the support in the area of the recess of the carrier is forced axially through the recess through deformation so that first a hollow attachment is formed whereby the carrier serves during deformation as the die and the hollow attachment thus formed is flanged over like a rivet head on the side of the carrier remote from the friction element or its support. The areas of the attachment protruding over the carrier are thus turned over in the radial direction.Through the method according to the invention the support receiving the friction lining can be formed at least substantially flat on its side facing the carrier, thus has no projections so that any hooking between the friction elements or with other component parts can be avoided. Furthermore the support or friction elements can be stacked in a simple space saving manner ready for assembly. According to the invention the areas adjoining a recess of the carrier thus serve during formation of the hollow attachment as a supporting area for the support of the friction element.

In order to produce the connection it can be particularly advantageous if the areas shaped out from the plane of a support have prior to deformation a central recess which defines a contour which has a smaller diameter than the associated recess of the carrier. It can be particularly expedient if prior to formation of a hollow attachment the areas of the support forming this attachment have a ringtype shape and lie at least approximately in one plane with the adjoining areas of the support. The areas to be deformed can also be off-set slightly axially relative to the areas of the support adjoining same or can have a slightly conical or dome-shaped design so that they protrude slightly axially.A design of this kind likewise allows a stacking of the supports or of the friction elements fitted with same whereby the slight conical formation or domeshaped design allows positioning in the transverse or radial direction between the supports or friction elements provided with same.

In order to make the rivet-type attachments it can be particularly expedient if the areas of a support serving to form such an attachment have a ring-type shape and have at least over a partial area of the radial extension of this ring-type shape radial cut-out sections which can be distributed at least approximately over the circumference.

These cut-out sections can thereby advantageously extend star-shaped from a central recess wherein it can be expedient if the cut-out sections form a recess with a cross-type shape. It can thus be advantageous to provide four cut-out sections diametrically opposite and in pairs.

According to a further design possibility the areas producing the connection between the support and carrier can be weakened prior to deformation at least in places at least over a partial area of their radial extension and viewed in the circumferential direction. A weakening of this kind can be formed by introducing notches which form ideal tear or ideal break points. These notches can thereby be provided additionally to the radial cut-out sections mentioned above or however in place of same.

The invention can be used particularly advantageously with supports of sheet metal which are each mounted on a lining spring segment of a clutch disc. The supports thereby consist of a material which has certain deep drawing properties. Since the spring segments consist of spring steel and have a comparatively high hardness or strength they can serve as a die for producing the hollow rivet type elements or rivet connection without danger of damage.

The method according to the invention or the design according to the invention can be used particularly advantageously in clutch discs which are constructed according to DE-PS 30 47 934. Such clutch discs have at least one entrainment disc which has radially protruding opposing spring segments on each of which a friction element is fixed by means of rivet connections wherein each rivet element on one side connects a spring segment to the friction element associated therewith in that the rivet element reaches through a rivet opening in the spring segment, and on the other side can project at least into a rivet head receiving opening of the opposing spring segment.

The invention will now be explained in further detail with reference to Figures 1 to 5 in which: Figure 1 is a view of a friction element prior to assembly looking onto the friction lining; Figure 2 shows a friction element mounted on a lining spring segment looking in the same direction as in Figure 1; Figure 3 likewise shows a friction element mounted on a lining spring segment, viewed from the reverse side of the friction element; Figures 4a to 4d show individual method steps for making the connection between a friction element and a lining spring segment; Figure 5 shows a detail of Figure 4d on an enlarged scale.

The friction element 1 shown in Figure 1 has a support formed by a sheet metal plate 2 on which a friction lining 3 is fixed. The friction lining 3 can be pressed and/or stuck onto the support 2 wherein between the friction lining and support still further mechanical or positive locking connections can be provided. Thus for example the support 2 can have on its outer circumference a protruding edge which surrounds the friction lining 3 as shown for example in Figure 2 of DE-PS 30 47 934.

The friction element 1 can in an advantageous manner and form be arranged as an essentially circular element, with the friction material being mounted on a carrier for example adhesively mounted.

The friction lining 3 of the friction element 1 which is designed as a pad has two diagonally arranged ring-shaped recesses 4,4a which serve to form the connections between the friction element 1 and a spring segment 5 according to Figure 2 or 6 according to Figure 3. Inside the recesses 4 there are areas 7 of the sheet metal support 2 which are deformed to form rivet-type fixing elements which fixedly connect the friction element 1 to a support designed for example as a spring segment 5 or 6. The area 7 deformable during fitting of the friction element 1 on a spring segment 5,6 is defined in Figure 1 radially outwards by the chaindotted line 8. As can be seen the outer diameter 8 of the area 7 is smaller than the diameter 9 of the recesses 4,4a.

The ring-shaped area 10 remaining between the diameters 8 and 9 serve for support during fitting of the friction element 1 on a spring segment 5,6.

The area 7 has in its centre a recess 11 which has a central circular shaped area from which emerge radially outwardly directed cut-out sections 12. In the illustrated embodiment one area 7 has four cut-out sections 12 arranged in a cross.

The cut-out sections 12 only extend over a partial area of the area 7 serving to form a rivet-type fixing element. It is also possible to provide instead of the cut-out sect ions 12 or in addition to these radial moulded areas in the area 7 to form ideal tear or ideal break points which support the formation of a rivet-type sleeve-shaped fixing element. To this end for example radially aligned notches can be formed in the material of the support 2 substantially opposite an area 7.

The ring-shaped area remaining between the diameter 8 of an area 7 and the radial outer ends of the cut-out sections 12 serves to form a circumferentially closed tubular sleeveshaped section of a rivet-type fixing element. This section which is circumferentially closed per se is located after fitting the friction element 1 on a spring segment 5,6 in the area of the material thickness of such a spring element whereby a solid cross connection between such a friction element 1 and a spring segment 5,6 is guaranteed.

The method of producing the connection between a friction element 1 and the associated carrier 5 in the form of a spring segment will now be described in further detail with reference to Figures 4a to 4d and 5.

The two parts 1 and 5 are first held relative to each other through means not shown in further detail in a position corresponding to Figure 2. The means for positioning the two parts 1 and 5 can be provided in a tool which has areas which engage on contours eg on the outer periphery or in recesses of the two parts 1 and 5 in order to position these accurately relative to each other.

The spring segment 5 and the support 2 of the friction element 1 made of sheet metal are tensioned axially at least in the area of the recesses 4. To this end a hollow holder or supporting ram 13 is provided on the side of the spring segment 5 remote from the friction element 1 and a counter holder or counter ram 14 which is likewise hollow is provided on the side of the friction element 1. The counter holder 14 engages in a recess 4 of the friction lining 3 and is supported on the support 2 whereby this and the spring segment 5 are tensioned and held firm axially between the two holders 13, 14. The counter holder 14 is supported on a ring-shaped area 10 (Figure 1) of the support 2.

The hollow holders 13,14 receive rivet or deformation rams 15,16 which are axially displaceable and preferably radially guided inside these holders 13,14.

As can be seen from Figure 4b, first the deformation ram 16 is moved inside the counter holder 14 axially in the direction of the spring segment 5 so that it can project into the recess 11 of the support 2 which is provided in the area 7. In order to make axial deformation of the area 7 easier the rivetting or deformation ram 16 has at its end area a taper 17 which is formed conical or frusto-conical in the illustrated embodiment. By moving the deformation ram 16 the area 7 is set up at least approximately at right angles to the support 2 whereby a sleeve type or hollow area 18 is formed which serves for both the rotationally secured and axially fixed connection between the two component parts 1 and 5.

After the sleeve-like area 18 has been formed the direction of movement of the deformation ram 16 is changed so that this moves back into its starting position. At the same time or just after, this is followed by the rivetting or deformation ram 15 which has at its end facing the spring segment 5 a moulded area 19 which is designed so that when it projects into the sleeve-type area 18 the areas 20 protruding over the spring segment 5 are turned over, namely relative to the opening of the sleeve-like area 18 radially outwards whereby a keyed rivet connection is produced between the sheet metal support 2 and the spring segment 5.

After the rivet connection 21 has been formed the holders 13, 14 and the rams 15, 16 can be retracted from the position shown in Figures 4d and 5 whereby the structural unit formed by a friction element and carrier 5 is released.

During the bending process of the area 7 to form a sleevetype area 18 the spring segment 5 serves as die. During the raising of the sleeve-type area 18 the areas Sb adjoining the recess Sa of the spring segment 5 thus serve to support the friction lining support plate 2. In order to form a rivet connection 21 the areas 7 are bent round the edge defined by the areas 5b.

The rivetting device can obviously also be designed so that all the rivet connections associated with the friction element 1 are made at the same time. This means that in the present case two rivet connections 21 can be made in one work step.

It can be seen from Figure 3 that after carrying out the operation according to Figure 4d the tab-type areas 22 originally existing between the cut-out sections 12 according to Figure 1 are bent down radially on the side of a spring segment 6 (or 5 ) remote from the friction element 1 and thus engage behind the spring segment 6 (or 5). The tab-type areas 22 thus protrude slightly beyond the spring segment 5, as is also apparent in connection with Figure 5.

Since the two friction elements 5 and 6 can be fitted back to back in a similar way, as described in DE-PS 30 47 934 the spring segments 5,6 each have in the area of the opposite rivet connections 21 receiving recesses 23,24 in which when the spring segments 5,6 are pressed flat the protruding areas 22 can project whereby an undesired support of the areas 22 on the spring segment opposite same can be avoided.

The spring segments 5,6 have a foot area 25 in which recesses 26 are provided to hold rivet elements for fixing on an entrainment disc, eg a clutch disc. The spring segments 5,6 have each side of the associated friction element 1 recesses 27,28 to receive connecting means such as rivets which connect the spring segments 5,6 arranged in pairs together so that these represent a preassembled structural group. This structural group can thus be fixed for example on the entrainment disc of a clutch disc.

The patent claims filed with the application are proposed wordings without prejudice for achieving wider patent protection. The applicant retains the right to claim further features disclosed up until now only in the description and/or drawings.

References used in the sub-claims refer to the further design of the subject of the main claim through the features of each sub-claim; they are not to be understood as dispensing with obtaining an independent subject protection for the features of the sub-claims referred to.

The subjects of these sub-claims however also form independent inventions which have a configuration independent of the subjects of the preceding sub-claims.

The invention is not restricted to the embodiment of the description. Rather numerous modifications and alterations are possible within the framework of the invention, more particularly those variations, elements and combinations and/or materials which are inventive for example through combination or modification of individual features or elements or method steps contained in the drawings and described in connection with those in the general description and embodiments and claims and lead through combinable features to a new subject or to new method steps or sequence of method steps where they relate to manufacturing, testing and work processes.

Claims

1. A method for connecting a friction element, consisting of a support and a friction lining fixed thereon, to a carrier which has at least one recess, wherein a connection is made by placing the carrier and support at least partially one on the other and forcing the material of the support in the area of the recess of the carrier by deformation axially through this recess so that a hollow attachment is formed wherein the carrier serves as the die during deformation and then the area of the attachment protruding on the side of the carrier remote from the support is flanged over like a rivet head.

2. A method according to claim 1 characterised in that the areas of the support deformed for producing the connection have a central recess prior to the deformation.

3. A method according to claim 1 or 2 characterised in that prior to deformation the areas of the support producing the connection have a ring-like shape and lie in one plane with the adjoining areas of the support.

4. A method according to one of claims 1 to 3 characterised in that prior to deformation the areas of the support producing a connection have a ring-type shape and have radial cut-out sections at least over a partial area of the radial extension of this ring-type extension.

5. A method according to claim 4 characterised in that the cut-out sections are formed star-shaped starting from a central recess.

6. A method according to one of claims 1 to 5 characterised in that prior to deformation the areas of the support producing the connection are weakened at least in places at least over a partial area of the radial extension - viewed in the circumferential direction.

7. A method according to claim 6 characterised in that the weakened areas are formed by introducing notches which form ideal crack or ideal break points.

8. A method according to one of claims 1 to 7 characterised in that the support consists of sheet metal and the carrier is formed by a spring segment.

9. A method according to one of Claims 1 to 8, characterised in that the friction element is constructed in the form of a circular ring.

10. A method according to one of claims 1 to 9 characterised in that the friction element is formed by a so-called pad.

11. A method according to one of claims 1 to 10 characterised in that a number of opposing spring segments is provided and these are fixed radially protruding on the outer area of an entrainment disc of a clutch disc and each spring segment is allocated a friction element.

12. A method according to one of claims 1 to 11 characterised in that each friction element is connected to the corresponding carrier through at least two fixing points.

13. A method for fixing a friction element consisting of a support and a friction lining fixed thereon, onto a carrier by means of at least one rivet-type connection wherein at least one of the support and the carrier, has, in order to produce this connection, at least one recess and this connection is produced by placing the carrier and support at least partially one on the other and forcing the material of the other of the two parts in the area of the recess of the one part through deformation axially through this recess so that a hollow attachment is produced whereby the one part having the recess serves as the die during deformation and then the area of the attachment protruding on the side of the one part remote from the other part is flanged over like a rivet head.

14. A friction element connected to a carrier by the method of any one of the preceding claims.

15. A method for connecting a friction element to a carrier, substantially as herein described with reference to the accompanying drawings.

16. A friction element connected to a carrier substantially as herein described with reference to the accompanying drawings.