GB2148415A

GB2148415A - Friction clutch cover assemblies

Info

Publication number: GB2148415A
Application number: GB08422113A
Authority: GB
Inventors: Roger Porter Jarvis; Keith Vernon Leigh-Monstevens; Alain Briand
Original assignee: Automotive Products PLC
Current assignee: Automotive Products PLC
Priority date: 1983-10-15
Filing date: 1984-08-31
Publication date: 1985-05-30
Also published as: GB8422113D0; GB2148415B

Abstract

A clutch cover assembly is disclosed in which the cover is fabricated from a number of prefabricated sector members (22) joined together at their ends (26). The ends (26) of each of the sector members (22) are formed to provide either an overlap joint (27a, 28a) as shown or a butt joint (not shown). The diaphragm spring (15a) is conveniently positioned by providing radially extending pips (32) on the outer periphery of the diaphragm spring (15a) which cooperate with windows (33) formed in a wall portion of the cover. The ends may be joined by rivets (31) or by welding or brazing. <IMAGE>

Description

SPECIFICATION Friction clutch cover assemblies This invention relates to a friction clutch cover assembly of the kind including a cover for fastening to a reaction plate or flywheel and a pressure plate for gripping a driven plate interposed between the reaction plate and the pressure plate, the pressure plate being axially movable relative to the cover and driven for rotation therewith.

A cover for a friction clutch cover assembly of this type is normally formed as a one piece pressing. Although the manufacture of such a pressing for small clutches does not present any great difficulties, it does result in a considerable amount of waste material. However, as the cover size increases a heavier gauge material is required to withstand the operating loads without excessive flexure or failure of the cover and, consequently, the pressing operation beomes more difficult, requiring the use of large press tools of considerable strength and cost.

It is an object of this invention to provide a friction clutch cover assembly in which the cover is easier and cheaper to manufacture than a one piece pressing.

According to the invention there is provided a friction clutch cover assembly of the kind referred to in which the cover comprises a number of prefabricated sector members, each having end portions that are joined together to form the cover.

The end portions may be overlapped where joined together to form the cover. Alternatively, the end portion may be in butting engagement where joined together to form the cover.

In one embodiment of the invention each sector member has one end portion formed into a flat fixing tab at one end and another end portion formed into a joggled fixing tab at the other end.

In another embodiment of the invention each sector member has a radially extending flange at each end that are joined together to form the cover.

In a clutch cover assembly of the kind in which a diaphragm spring is positioned between the pressure plate and the cover the diaphragm spring may have pips on its periphery which co-operate with windows in the cover thereby locating it.

Alternatively, to locate the diaphragm spring each of the joggled fixing tabs may have an inwardly directed finger adapted to co-operate with a pip on the periphery of the diaphragm spring.

Some embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, of which: Figure 1 is a half plan view of a first embodiment of a clutch cover assembly according to the invention; Figure 2 is a cross section on the line ll-ll of Fig. 1; Figure 3 is a view in the direction of arrow Aon Fig. 1; Figure 4 is a cross section on the line IV-IV of Fig. 1; Figure 5 is a cross section on the line V-V of Fig. 1; Figure 6 is a cross section similar to Fig. 5 of an alternative construction detail; Figure 7 is an enlarged isometric view of the detail of Fig. 6; Figure 8 is a half plan view of a second embodiment of a clutch cover assembly according to the invention; Figure 9 is a view in the direction of arrow B on Fig. 8;; Figure 10 is a cross section on the line X-X of Fig. 8 showing a further constructional detail; Figure ii is an enlarged isometric view of the detail of Fig. 10; Figure 12 is an enlarged isometric view of the detail of Fig. 10 showing parts before assembly; and Figure 13 is a plan view of a third embodiment of the invention showing a plan view of part of a cover assembly accoiding to the invention.

With reference to Fig. 1 to 5 there is shown a clutch cover assembly including a cover 11 for fastening to a reaction plate in the form of a flywheel 1 2. A pressure plate 1 3 for gripping a driven plate 1 4 is interposed between the pressure plate 1 3 and the flywheel 1 2.

The pressure plate 1 3 is biased away from the cover 11 by a diaphragm spring 1 5 and is attached to the cover by three resilient straps 1 6. The straps 1 6 allow for a limited axial movement of the pressure plate 1 3 while permitting the transfer of torque between the cover 11 and the pressure plate 1 3. Each strap 1 6 extends substantially tangentially from a position of attachment 1 7 on the cover 11, where it is secured by a rivet 1 8, to a position of attachment 1 9 on the pressure plate 1 3 where it is secured by another rivet 20.The positions of attachment 1 9 to the pressure plate 1 3 are on lugs 21 extending radially outwardly from the outer periphery of the pressure plate 1 3.

The cover 11 is of a prefabricated type in which three sector members 22 are mechanically joined together to form the cover 11. In radial cross section each sector member 22 has a substantially flat flange portion 23 for fixing to the flywheel 12, a double curvature wall portion 24 and an inner rim portion 25.

The flange portion 23 extends beyond both ends 26 of the wall and rim portions 24 and 25 to form a flat fixing tab 27 at one end and a joggled fixing tab 28 at the other end, each tab 27, 28 having a radially centrally posi tioned hole 29.

Upon assembly the joggled tab 28 of each sector member 22 is overlapped with the flat tab 27 of the adjacent sector member 22 so that the holes 29 are aligned. The overlapping tabs 27 and 28 are then secured together by an annular spot weld 30 encircling the locating holes 29. The holes 29 may also be used to position the cover 11 on the flywheel 1 2 by means of doweis (not shown).

To prevent excessive movement of the pressure plate 1 3 away from the cover 11 during transit, the straps 1 6 are attached to the outer surface of the cover 11. The flange portion 23 of each sector member 22 is locally deflected away from the strap 1 6 to provided an abutment 34 extending from the position of attachment 1 7 of the strap 1 6 to the cover 11 to a position where the flange portion 23 is cut back to allow for passage of the lug 21.

If the pressure plate 1 3 moves outwardly from the cover 11 then contact between the strap 1 6 and the abutment 34 will initially occur close to the position of attachment 1 7 of the strap 1 6 to the cover 11. Further outward movement of the pressure plate 1 3 results in a zone of contact spreading towards the position of attachment 1 9 of the strap 1 6 to the lug 21. This helps to protect the straps 1 6 from sudden shock loads caused by instantaneous contact with the abutment surface 34.

As an alternative to spot welding adjacent pairs of tabs may be secured by riveting as shown in Figs. 6 and 7 in which case the fixing rivet 31 can be used to locate the cover 11 a on the flywheel 12a. The diaphragm spring 1 5a is conveniently positioned by providing three pips 32 on the outer periphery of the diaphragm spring 1 5a which co-operate with recesses in the form of windows 33 formed in the wall portion 24a at the junction of adjacent sector members 22a.

In the second embodiment of the invention shown in Figs. 8-12, many parts of the cover assembly are similar to or modifications of those described with respect to Figs. 1-7, so that where appropriate the same reference numerals are used with the addition of 100 and only the differences and modifications will be described in full.

The diaphragm spring 11 5 is positively located in a manner similar to that described with reference to Figs. 6 and 7. Pips 1 32 cooperate with recesses in fingers 1 35 formed in each of the joggled fixing tabs 1 28.

To allow for the passage of the fingers 1 35 the wall portion 1 24 is circumferentially slotted where it joins the flat tab 1 27.

The overlapped junction of each joggled tab 1 28 with its adjacent tab 1 27 is secured by a spot weld 1 30.

In a manner similar to that described in relation to Figs. 1-5, each of the straps 11 6 connecting the pressure plate 11 3 to the cover 111 extends from a position of attachment 11 7 on the cover to position of attachment 11 9 on the pressure plate 11 3. However, the flange portion 1 23 adjacent to each position of attachment 11 7 of the strap to the cover 111 is deformed away from the strap 11 6 to provide a ledge 1 34. The ledges 1 34 are parallel to the flange 1 23 and each has a window 1 33 formed in it to allow for the passage of the adjacent lug 121.An edge 1 36 of each of the windows forms an abutment for co-operating with the strap 11 6.

In normal use each lug 121 on the pressure plate 11 3 extends beyond the edge 1 35 and no contact occurs between the edge 1 36 and the adjacent strap 11 6. If, during transit there is movement of the pressure plate 11 3 away from the cover 111 the straps 11 6 can contact the edges 1 36 and damage to the straps 11 6 is prevented.

With reference to Fig. 1 3 there is shown a third embodiment of the invention in which the cover assembly is similar to that described in GB.1229676. The cover. however, comprises four sector members only two of which are shown. The sector members 212, 213 are of equal circumferential length and each has an end portion at both ends in the form of a flange 214. Each of the flanges 214 has a radially extending face 215 for abutment with the radially extending face 21 5 of the adjoining sector member 212 or 213. Each of the sector members 212, 213 has an inner peripheral flange 224 extending between the two end flanges 214 and an outer peripheral flange 225 extending between fixing regions 218 each of which has a through hole 220 to allow the passage of a securing bolt. (not shown). At one end of each of the sector members 212, 213 there is provided a location hole 219 for co-operation with a dowel pin (not shown).

The sector members 212, 213 are also provided with rivet holes 216 through which diaphragm spring securing rivets pass to secure the diaphragm spring to the cover, and a hole 21 7 to allow the passage of a rivet securing a drive strap (not shown) to the cover.

To assemble the cover the four sector members are joined together by bringing adjacent radially extending faces 215 into abutting engagement and securing the flanges together by welding. This takes the form of spot welding but brazing or riveting may also be employed.

Claims

1. A friction clutch cover assembly including a cover for fastening to a reaction plate or flywheel and a pressure plate for gripping a driven plate interpoosed between the reaction plate and the pressure plate, the pressure plate being axially movable relative to the cover and driven for rotation therewith, wherein the cover comprises a number of fabricated sector members each having end portions that are joined together to form the cover.

2. A friction clutch cover assembly as claimed in Claim 1 in which the end portions are overlapped and joined together to form the cover.

3. A cover assembly as claimed in Claim 2 in which each sector member has a first end portion formed into a flat fixing tab at one end and a second end portion formed into a joggled fixing tab at the other end.

4. A cover assembly as claimed in Claims 1 to 3 in which the end portions are joined by welding or brazing.

5. A cover assembly as claimed in Claims 1 to 3, in which the end portions are joined by spot welding.

6. A cover assembly as claimed in Claim 5, in which the spot welds are annular and encircle a location hole in each sector member.

7. A cover assembly as claimed in Claims 1 to 3 in which the end portions are joined by fixing rivets.

8. A cover assembly as claimed in Claim 7, wherein the fixing rivets are adapted to locate the cover on the reaction plate on flywheel.

9. A cover assembly as claimed in any preceding claim in which a diaphragm spring is located between the pressure plate and the cover, the diaphragm spring having pips around its periphery for co-operation with locating recesses in the cover.

10. A cover assembly as claimed in Claim 9, in which the recesses are in the form of windows in a wall portion of the cover.

11. A cover assembly as claimed in Claim 10, in which the windows are formed at the junction of adjacent sector members.

1 2. A cover assembly as claimed in Claim 5, in which the recesses are formed in fingers extending radially inwardly from the cover.

1 3. A cover assembly as claimed in Claim 12, in which the fingers extend from sector members.

14. A cover assembly as claimed in Claim 13, in which each of the fingers extends from an end portion of the sector members.

1 5. A cover assembly as claimed in Claim 1, in which the end portions are in butting engagement and are joined together to form the cover.

16. A cover assembly as claimed in Claim 15, in which each sector member has a radially extending flange at both ends.

1 7. A ccover assembly as claimed in Claim 16, in which radially extending faces of the radially extending flanges are in butting engagement and the flanges are joined together to form the cover.

1 8. A cover assembly as claimed in Claims 1 5 to 17, in which the end portions are joined by welding.

1 9. A cover assembly as claimed in Claims 1 5 to 17, in which the end portionns are joined by riveting.

20. A cover assembly as claimed in Claims 1 5 to 1 7 in which the end portions are joined by brazing

21. A friction clutch cover assembly substantially as herein described with reference to Fig. 1 3 of the accompanying drawings.

21. A cover assembly as claimed in Claim 18 in which the end portions are joined by spot welding.

22. A friction clutch assembly substantially as herein described with reference to Figs. 1 to 7 or Figs. 8 to 1 2 of the accompanying drawings.