GB2275521A

GB2275521A - Improvements in clutch plates

Info

Publication number: GB2275521A
Application number: GB9403552A
Authority: GB
Inventors: Erwin Wack; Karlheinz Hofmann; Johann Spitzhirnn; Albert Kammermeier; Juergen Kleifges; Reinhard Feldhaus
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1993-02-27
Filing date: 1994-02-24
Publication date: 1994-08-31
Anticipated expiration: 2014-02-24
Also published as: FR2702019B1; FR2702019A1; GB9403552D0; ES2109128B1; ES2109128A1; GB2275521B

Abstract

The hub disc (3) and/or sheet metal covers (5, 6) of a clutch plate are formed as fine-blanked sheet metal components, which enables the connections between them and the other components to be in the form of welded connections (19). The fine-blanking is stated to strengthen the edges of the spring windows. The covers may be welded together (Figs 2 and 4), or to the hub, (Fig 3) and the disc may be welded to two hub members (Fig 6). … <IMAGE> …

Description

2275521 IMPROVEMENTS IN CLUTCH PLATES The invention relates to a clutch

plate for a friction clutch in a motor vehicle comprising a hub with internal splines, a hub disc and at least one sheet metal cover, which are in the form of substantially disc-shaped components with windows for receiving and locating energy-storing springs, one of the components, the hub disc or the cover, being provided with friction linings and the other being secured permanently to the hub and the clutch plate being arranged concentrically with respect to an axis of rotation.

A clutch plate of the above-mentioned construction is known, for example from German Patent Application No. 40 11 498. Problems arise in particular in the hub disc - but also in the sheet metal covers - of such clutch plates in that the circumferential end edges of the windows for locating the energy-storing springs are subjected to increased wear if special counter-measures are not undertaken. One effective but expensive measure is to harden the edges of the windows. This gives rise to the danger of distortion of the components which are provided with the windows. Moreover it is not immediately possible to weld the hardened material to other components. For example, the material must be further treated by machining in the region of the welding points which are provided, and this means a really high outlay.

It is the aim of the present invention to increase the durability and strength of the components of clutch plates without having to take into account the draw-backs in welded connections.

2 According to the invention it is therefore proposed that a clutch plate for a friction clutch in a motor vehicle comprise a hub with internal splines, a hub disc and at least one sheet metal cover, which are in the form of substantially disc-shaped components with windows for receiving and locating energy-storing springs, one of the components, the hub disc or the cover, being provided with friction linings and the other being secured permanently to the hub and the clutch plate being arranged concentrically with respect to an axis of rotation, in which the hub disc and/or the cover or covers is or are formed as fine-blanked sheet metal components and the rigid connections between them and between them and other components are in the form of welded connections.

By the fine-blanking of hub disc and/or sheet metal cover the result is a strengthening of the edges which solves the problem of wear at the points in question. At the same time the material which can then be employed is capable of being welded without problems so that the previously necessary hardening process with its danger of distortion of the components in question can be omitted without any substitute. As the material for these substantially disc-shaped components one can for example employ coldrolled QStE 500 TM having sufficient basic strength.

According to a further feature of the invention it is proposed that two sheet metal covers are provided, held rigidly together but spaced apart by means of connecting elements. Independently of the manner in which the two covers are in a rotational connection to the hub, here all of the connections between the sheet metal covers - regardless of whether using separate connecting elements or using connecting elements 3 arranged in one piece with one of the covers - can be formed by welding, and in view of the welding process no particular machining step is necessary.

According to a further proposal of the invention hub disc and/or sheet metal cover or covers are formed as fine-blanked components and the rigid connection to the hub and to each other is formed as a welded connection. In a clutch plate, in which the hub disc is connected rigidly to the hub and at least one sheet metal cover is provided and is arranged to be rotatable in relation to the hub disc against the force of the energy-storing springs, it is proposed that the hub disc should be mounted by means of an opening which is concentric to the axis of rotation on a matching seating on the hub concentric with the axis of rotation possibly engaging against an axial stop - and the two components are connected together by a seam weld in the seating-opening region. With such a construction the hub can be manufactured with its difficult internal splines separately from the hub disc, which has great advantages lying in the fact that in the manufacture of the hub little machined waste arises. In this connection the hub disc is produced from a fine-blanked sheet metal component in which an edge- strengthening at the windows for the spring elements during the fine-blanking process ensures an extended working life and the hub and the hub disc can be easily and permanently connected together in the seating-opening region by a seam weld. In this connection it is not necessary for the seam weld to be of a circumferentially continuous form and it is also possible to form the connection by short, separate and unjoined seam welds.

4 It is further proposed in clutch plates, in which the hub disc is rigidly connected to the hub and at least one sheet metal cover is provided and is arranged to be rotatable with respect to the hub disc against the force of the springs, that the hub disc should be provided in its radially inner region with a hub member projecting from at least one side in the form of a tubular piece, one face of the tubular piece lying axially opposite a corresponding face on the hub disc and the two of them being connected together in this region by means of a seam weld. Using such a construction both the hub disc and also the or each of the corresponding hub components can be produced separately, the hub disc being made by fine-blanking and using a weldable material and being capable of being welded to the tubular piece without further treatment and at the same time the windows have the necessary strength. In this connection the advantage of the fine-blanking process used for the windows applies not only to these but also for any possible stop edges which are arranged at the periphery for the hub disc and are provided as a rotational stop. Using this construction the low-energy and low cost capacitor discharge welding process can be employed to advantage. in this way on the one hand distortion of the individual components is avoided and on the other hand the strengthening of the edges is not adversely affected.

In a clutch plate in which two sheet metal covers are rigidly connected to the hub spaced from apart from one another axially and the hub disc is arranged between them to be rotatable with respect to the covers and the hub against the force of the spring, it is proposed that the sheet metal covers should be mounted on the hub with openings concentric with the axis of rotation on matching seatings concentric with the axis of rotation on the hub - possibly on an axial stop in the form of a central region of larger diameter - and each cover is rigidly secured to the hub by means of a seam weld in the opening-seating region. Such a layout is very simple in construction and i,s arrived at with few individual components, because the rivets and the space necessary for them in the hub at this point can be omitted without any substitutes.

The invention is further explained in the following description in conjunction with various embodiments by way of example. In the drawings,

Figure 1 shows the upper half of the longitudinal section through a clutch plate with a welded connection between the hub disc and hub; Figure 2 shows the lower half of the longitudinal section through a clutch plate with a welded connection between the two sheet metal covers; Figure shows the upper half of a longitudinal section through a construction having two sheet metal covers which are both rigidly connected to the hub; Figure 4 is a partial section through a clutch plate having two sheet metal covers which are connected together in their radially outer region and held spaced apart; Figures 5 and 6 show an elevation and section through a clutch plate in which the hub disc is welded at the sides to tubular pieces which have internal splines.

6 Figures 1 and 2 show longitudinal sections through a clutch plate in which a hub 2 is arranged concentrically with respect to an axis of rotation 17. The hub 2 has internal splines for mounting on and rotation with, a gearbox shaft, not shown. Rigidly connected to the hub 2 is a hub disc 3 which has a number of circumferential distributed windows 9 for locating energy storing springs 25. Arranged on each side of the hub disc 3 is a sheet metal cover 5 and 6, the two of them, as shown in Figure 2, being rigidly connected together and the same time held spaced apart by spacers 22, and which likewise have windows for locating the springs 25. The cover 6 is rigidly connected in the region of its outer periphery, furthermore, through lining carriers 11 to friction linings 16. The two covers 5 and 6 together with the friction linings 16 form a unit which, when subjected to torque, can perform a relative rotation in relation to the hub 2 and the hub disc 3 against the force of the springs 25. In the present case both the sheet metal covers 5 and 6 and also the hub disc 3 are manufactured as fine-blanked sheet metal components, whereby on the one hand a material which can be welded without difficult can be employed and whereby on the other hand the windows receive a local increase in strength in order to take the torque of the springs 25, whereby a degree of restriction is offered to wear taking place at these points. The hub disc 3 in this arrangement is mounted by means of an opening concentric with the axis 17 on a matching seating on the hub 2 and the two components are welded together in the seating-opening region by a seam weld 19. In this connection this seam weld 19 can extend all the way around. However, it is is also possible to provide individual weld regions. The hub 2 in the present case is provided with an axial stop 18 which serves as a 7 location between the hub disc 3 and the hub 2 before the welding takes place.

By the manufacture of the two sheet metal covers 5 and 6 in the same way it is possible to realise their interconnection which simultaneously produces the axial spacing, likewise by a welding process. For this purpose a number of circumferentially distributed spacers 22 are inserted between the two covers 5 and 6, projecting into corresponding openings in the covers and are anchored in place by corresponding seam welds 19. These spacers 22 could be made from sheet material or could equally well be turned components.

As the starting material both for the covers 5 and 6 and also for the hub disc 3 having sufficient basic strength a suitable material is for example cold-rolled steel of QStE 500 TM quality. In contrast to the methods previously employed, involving hardening of the sheet metal covers and the hub disc in the region of the windows in order to increase the strength, this material needs no subsequent machining in the region of the welds as it is per se weldable. Despite this characteristic, by the use of the fine-blanking technique it receives sufficient strength in the region of the windows which control the storage spring, to allow no wear to arise at these points.

In Figure 3 there is illustrated a construction in which the hub 1 is connected rigidly to two sheet metal covers 7 and 8 which have a predetermined spacing apart from one another. The hub disc 4 is arranged axially between the two covers 7 and 8 and is provided at its radial outer region, through lining carries 11, with friction linings 16. The hub disc 4 is guided for rotation relative to the hub 1 in a circumferential 8 direction against the force of the springs 25, these springs being arranged in windows in the covers 7 and 8 and in windows 9 in the hub disc 4. To maintain the axial spacing between the two covers 7 and 8 the hub 1 can be provided with a region 23 of larger diameter forming an axial stop for each of the covers.

Each of the two sheet metal covers 7 and 8 is provided with an opening which is concentric with respect to the axis 17 and by which it is mounted on a matching seating on the hub 1 and is secured at that point by a seam weld 19. By the manufacture of the two covers 7 and 8, for example from a cold-rolled QStE 500 TM having sufficient basic strength, and by the manufacture of the necessary windows for locating the springs 25 by the fine-blanking method it is possible to achieve the necessary strength for the windows without having to perform a hardening step, and so the material which is provided is directly capable of being welded. it is naturally also possible to produce the hub disc 4 in this way.

Figure 4 shows a partial section through a clutch plate in the region of, and radially outside, the springs, the two sheet metal covers 7 and 8 being held together whilst spaced apart in their radially outer region and rigidly secured together. For this purpose the cover 8 is provided with a number of axially bent. over tongues 21 which pass through corresponding openings 24 in the hub disc and are connected directly to the opposite cover 7 by a seam weld 19. In this connection the tongues 21 can naturally engage with their ends against the side face of the cover 7 but they could alternatively also be made axially longer and engage over the outer periphery of the cover 7 and be welded 9 there. The remainder of the construction corresponds to that of Figure 3.

In Figures 5 and 6 is shown an elevation and section through a clutch plate in which the hub disc 3 is formed as a fine-blanked component and the windows 9 and 12 are made durable by the reinforcement of the edges which takes place during the manufacturing process. The same applies also to the edges 15 which are provided in the region of the outside diameter of the hub disc 3 and which function as stops to limit the angular movement. They are provided in notches 14 into which for example the spacers 22 of Figure 2 extend and they form together with these spacers 22 the corresponding angle-limiting stop. The edges 10 and 13 co-operate with the springs 25 for example according to Figure 1 and cause compression of these springs when subjected to torque. In this connection these springs can both be in the form of metallic coil springs but it is also however, possible without difficulty to employ springs made of rubber or similar resilient material, and these can then advantageously be provided with guiding elements which engage against the edges 10 and 13.

It is evident in particular from Figure 6 that the hub disc 3 is rigidly secured on both sides to a respective hub portion 2a and 2b, the connection being through seam welds 19. The hub portions 2a, 25b are provided with internal splines for mounting on, and rotation with, a gearbox shaft and all the components are concentric with respect to the axis 17. The hub disc 3 itself can likewise be provided with splines, but it is entirely possible to do without any splines in the hub disc 3. The seam weld 19 can in this connection be made advantageously by employing a capacitor discharge welding process and with this in mind the two hub portions 2a, 2b are provided before welding with a web or bead 20 which takes part in the welding process at least partially as material in the weld.

1 1 11

Claims

1 A clutch plate for a friction clutch in a motor vehicle comprising a hub with internal splines, a hub disc and at least one sheet metal cover, which are in the form of substantially disc-shaped components with windows for receiving and locating energy-storing springs, one of the components, the hub disc or the cover, being provided with friction linings and the other being secured permanently to the hub and the clutch plate being arranged concentrically with respect to an axis of rotation, in which the hub disc and/or the cover or covers is or are formed as fine- blanked sheet metal components and the rigid connections between them and between them and other components are in the form of welded connections.

2. A clutch plate according to claim 1, in which two sheet metal covers are provided, rigidly connected together through connecting elements and held spaced apart.

3. A clutch plate according to claim 2, in which the two sheet metal covers are provided, rigidly connected and held spaced apart by a welded seam.

4. A clutch plate according to claim 1, in which the hub disc and/or sheet metal cover or covers is or are formed as fine-blanked components and the rigid connection to the hub or between them is or are formed as a welded connection.

5. A clutch plate according to claim 4, in which the hub disc is permanently connected to the hub and at least one sheet metal cover is provided and is arranged 12 to be rotatable in relation to the hub disc against the force of the springs, the hub disc is mounted with an opening concentric with respect to the axis of rotation on a matching seating of the hub concentric to the axis and both components are connected by a seam weld in the region of the seating and opening.

6. A clutch plate according to claim 5, in which the hub disc is mounted with the opening concentric with respect to the axis of rotation on the matching seating on the hub concentric to the axis and engaging against an axial stop, both components being connected by the seam weld in the region of the seating and opening.

7. A clutch plate according to claim 4, in which the hub disc is permanently secured to the hub and at least one sheet metal cover is provided and is arranged to be rotatable in relation to the hub disc against the force of the springs, the hub disc is provided in its radially inner region projecting from at least one side with a hub portion in the form of a tubular piece, one face of the tubular piece lying opposite a corresponding face of the hub disc and the two being connected together in this region through a seam weld.

8. A clutch plate according to claim 4, in which two cover plates are connected to the hub spaced apart from one another axially and the hub disc is arranged to be rotatable with respect to the sheet metal covers and the hub against the force of the springs, the sheet metal covers are mounted on the hub with openings concentric with the axis of rotation on matching seatings concentric with the axis and each sheet metal cover is rigidly connected to the hub by a seam weld in the opening-seating region.

13

9. A clutch plate according to claim 8, in which the sheet metal covers are mounted on the hub with the openings concentric with the axis of rotation on the matching seatings concentric with the axis on an axial stop in the form of a central region of larger diameter.

10. A clutch plate substantially as described herein with reference to any of Figures 1 to 6 of the accompanying drawings.

11. A method of construction of a clutch plate substantially as described herein with reference to any of Figures 1 to 6 of the accompanying drawings.