GB2193284A

GB2193284A - A friction clutch for a vehicle

Info

Publication number: GB2193284A
Application number: GB08618330A
Authority: GB
Inventors: Anthony William Breeze
Original assignee: Automotive Products PLC
Current assignee: Automotive Products PLC
Priority date: 1986-07-28
Filing date: 1986-07-28
Publication date: 1988-02-03
Anticipated expiration: 2006-07-28
Also published as: GB8618330D0; GB2193284B

Abstract

The friction clutch comprises a diaphragm spring 14 formed with a plurality of slots 20 extending outwardly from a central aperture 22. A hub 13 has a surface 25 in engagement with the diaphragm spring and through which load is applied, in use, to the spring to release the clutch. A resilient element 26 is arranged between the spring and the hub for holding the spring and hub in axial interengagement, said resilient element including a plurality of tongues 128 extending through the slots in said spring. <IMAGE>

Description

SPECIFICATION A friction clutch for a vehicle The invention relates to a friction clutch for a vehicle and is particularly concerned with a friction clutch of the kind including a slotted diaphragm spring and a hub member for applying a load to the spring to release the cluch, the hub member being held in axial engagement with the spring by a resilient element. Such a friction clutch is described in U.K. Patent No. 1069300 and an object of the present invention is to provide a friction clutch which has improved means for holding the hub and clutch spring in axial interengagement.

According to the invention there is provided a friction clutch comprising a diaphragm spring formed with a plurality of slots extending outwardly from a central aperture, a hub having a surface in engagement with the diaphragm spring and through which load is applied, in use, to the spring to release the clutch, and a resilient element arranged between the spring and the hub for holding the spring and hub in axial interengagement, said resilient element including a tongue extending through one of the slots in said spring.

The tongue may be positioned radially outwardly of the hub.

The resilient element may comprise an annular washer with said tongue extending axially therefrom. Preferably the tongue has a free end which is reverse bent inwardly towards the axis of the clutch, the annular washer being spaced from the bent free end with the clutch spring and a portion of the hub gripped therebetween. The tongue may extend from a peripheral edge of the annular washer. Prefera bly, the resilient element includes a plurality of circumferentially spaced said tongues located in respective slots in the diaphragm spring.

The clutch hub may include a radial flange engaging a side of the clutch spring facing a driven member of the clutch with the resilient element urging the radial flange and spring into engagement with each other.

The hub may include a tubular portion extending axially through the central aperture in said diaphragm spring. Preferably, said tubular portion is connected to a member of a clutch release mechanism by a releasable detent. In such a case, the releasable detent may be located in an opening in one of said tubular portion and member and is preferably radially deformable to permit the tubular portion to be connected to or reieased from said member of said clutch release mechanism. The detent may define an ear which locates in a further opening in one of said tubular portion and member. The detent may be ring-like and may have adjacent free ends which allow the ring to expand or contract radially to facilitate connection or release of the tubular portion.The tubular portion may be formed with a plurality of further opening which receive respective ears formed on said detent. Preferably, the first said opening receives free end sections of said clip.

The first said opening may be open in the axial direction to permit entry of said free end sections into said opening. Preferably, the member of said clutch release mechanism is formed so as to snap fit into engagement with said detent to connect with said hub so that clutch release forces can be applied to the hub via the detent, said member being releasable from said hub by first causing the detent to expand or contract radially and then withdrawing the member from engagement with the detent. The detent may be expanded or contracted by moving its free ends manually.

Preferably, said one of the tubular portion and member is formed with an inclined surface which engages the detent and urges it against the other of said tubular portion and member during application of clutch release forces.

Preferably, the member of said clutch release mechanism is formed so as to snap fit into engagement with said clip to connect with said hub so that clutch release forces can be applied to the hub via the clip, said member being releasable from said hub by first causing the clip to expand and then withdrawing the member from engagement with the clip. Such an arrangement makes the assembly together and disassembly of the hub and the said member particularly straightforward. The clip may be expanded by moving the free ends of the clip apart manually.

The hub may be formed with an inclined surface which engages the clip and urges it against the said member during application of clutch release forces.

A friction clutch in accordance with the invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a longitudinal cross section through a friction clutch in accordance with the invention., Fig. 2 is an end view of part of a diaphragm clutch spring of the clutch in Fig. 1 drawn to a smaller scale, Fig. 3 is an end view of a spring hub of the clutch of Fig. 1 drawn to a larger scale, Fig. 4 and 5 are views of the spring hub of Fig. 3 looking in the direction of arrows Y and Z in Fig. 3 respectively, Fig. 6 is a cross section of the spring hub of Fig. 3 on the line VI VI in Fig. 3, Fig. 7 is an end view of a clip for interconnecting the spring hub and a member of a clutch release mechanism, Fig. 8 is a cross section of the clip of Fig.

7 on the line VIII-VIII in Fig. 7.

Fig. 9 is an end view of a resilient element for holding the clutch spring and spring hub together, and Fig. 10 is a cross section of the element of Fig. 9 on the line X-X in Fig. 9.

In Fig. 1 there is shown a friction clutch in accordance with the invention in which a clutch pressure plate 10 is retracted by a clutch release mechanism 11 to release a clutch driven plate 12 drivably connected, in use, to an input shaft (not shown) of a gearbox. Clutch release is effected by applying a force in direction A to a hub 13 of a clutch spring 14 through an outer race 15 of a release bearing 16, an inner race 17 formed by a short hollow shaft 18, and a resilient detent clip 19 arranged between the shaft 18 and spring hub 13. The clutch spring 14 is of the diaphragm type and a section of such a spring is shown in Fig. 2. The spring is circular and is formed with a plurality of radial slots 20 extending from a central aperture 22. The radially outer ends of the slots 20 terminate at circular apertures 23.Release forces are applied to the radially inner ends of spring fingers 24 defined between the slots 20 by means of an annular flange 25 formed on the hub 13. The flange 25 and the spring fingers 24 are held in axial engagement with each other by means of a resilient element 26 as described below.

Various sections of the clutch will now be described in detail with reference to the remaining drawings.

The spring hub 13 is shown in detail in Figures 3 to 6 and comprises a stepped tubular section 30 integral with the flange 25. The section 30 is formed with two rectangular apertures 32 and a relatively larger rectangular aperture 33. An axial slot 34 is formed in the tubular section 30 so as to extend between an edge of the section 30 and the aperture 33. As shown in Fig. 1, the tubular section 30 extends through the central aperture 22 in the diaphragm spring 14.

The detent clip 19 is formed from spring steel wire and is bent to form two spaced apart ears 40 and two free end sections 42.

As apparent from Fig. 7 the clip is of generally circular form and the ears and free end sections projecting subtantially radially therefrom. The ears are circumferentially spaced so as to locate with working clearance within the apertures 32 with the free end sections 42 in the aperture 33 as shown in broken lines in Fig. 3. The free end sections 42 are drawn together to enable them to pass through the slot 34 when assembling the clip on to the hub 13. The ears 40 and free end sections 42 retain the clip loosely in the hub 13.

The short hollow shaft 18 is formed with a bevelled leading edge 43 (Fig. 1) and an external peripheral groove 44. The inside diameter d of the clip 19 in its relaxed condition is such that the spring hub 13 and hollow shaft 18 can be interconnected by urging the bevelled leading edge 43 axially to the left as viewed against the clip so that it rides up the bevelled edge and expands radially until it eventually rides on the external cylindrical surface of the shaft. Further axial movement of the shaft 18 causes the clip 19 to snap into the groove 44 whereupon releasing forces can be applied to clutch spring by moving the shaft 18 in direction A.

As will be appreciated from Fig. 6, the stepped tubular portions 30 includes a reduced diameter section 45 which includes a frusto conical surface 46. Application of clutch release forces to the clip 19 causes the clip to be drawn against the surface 46 which tends to contract the clip and therefore urge it firmly into the groove 44. The shaft 18 fits with working clearance within the reduced diameter section 45, the latter being chamfered at 47 to assist location of the shaft. The resilient element 26 prevents leftward axial movement of the hub 13 relative to the spring 14. When interconnecting the shaft 18 and hub 13 as described above.

As shown in Figs. 9 and 10, the resilient element 26 comprises an annular washer portion 27 having nine tongues 128 extending from the outer periphery thereof. Each of the tongues is reverse bent inwardly towards the axis of the element and comprises an axial section 21 and a terminal section 28. The section 28 is inclined at an angle 0, e.g.

around 20 to the axial section 21 of the tongue. As apparent from Fig. 1, the resilient element 26 is located around the hub 13 with the left hand surface of washer portion 27 resiliently engaging the spring fingers 24, the right hand ends of terminal sections 28 resiliently engaging the left hand surface of the flange 25 and the axial sections 21 of the tongues extending through associated slots 20 in the spring 14. In that way, the spring 14 and flange 25 are gripped between opposite sections of the resilient element. The use of the element 26 is advantageous in that no groove or the formation on the hub 13 as required in No. 1069300 is necessary to locate the free ends of the tongues. Also, the axial sections of the tongues do not occupy space within the hub 13, and assembly of the spring hub 13, spring 14 and resilient element 26 is quick and simple.

To disassemble the shaft 18 from the spring hub 13, the free end sections 42 of the clip 19 are moved manually apart to expand the clip. The clip is expanded out of the groove 44 sufficiently to permit withdrawal of the shaft 18 from the clip on application of clutch release forces in direction A to the shaft 18.

Claims

1. A friction clutch for a vehicle comprising a diaphragm spring formed with a plurality of slots extending outwardly from a central aper ture, a hub having a surface in engagement with the diaphragm spring and through which load is applied, in use, to the spring to release the clutch, and a resilient element arranged between the spring and the hub for holding the spring and hub in axial interengagement, said resilient element including a tongue extending through one of the slots in said spring.

2. A friction clutch according to Claim 1 in which said tongue is positioned radially outwardly of the hub.

3. A friction clutch according to Claim 1 or 2 in which said resilient element comprises am annular washer with said tongue extending axially therefrom.

4. A friction clutch according to Claim 3 in which the tongue has a terminal end section which is reverse bent inwardly towards the axis of the clutch, the annular washer being spaced from the bent free end with the clutch spring and a portion of the hub gripped therebetween.

5. A friction clutch according to Claims 3 or 4 in which the tongue extends from an outer peripheral edge of the annular washer.

6. A friction clutch according to any preceding Claim in which the clutch hub includes a radial flange engaging a side of the clutch spring facing a driven member of the clutch and the resilient element urges the radial flange and spring into engagement with each other.

7. A friction clutch according to any preceding claim in which the resilient element includes a plurality of circumferentially spaced said tongues located in respective slots in the diaphragm spring.

8. A friction clutch according to any preceding claim in which the hub includes a tubular portion extending axially through the central aperture in said diapgram spring.

9. A friction clutch according to Claim 8 in which said tubular portion is connected to a member of a clutch release mechanism by releasable detent.

10. A friction clutch according to Claim 9 in which the releasable detent is located in an opening in one of said tubular portion and member and is radially deformable to permit the tubular portion to be connected to or released from said member of said clutch release mechanism.

11. A friction clutch according to Claim 10 in which the detent includes an ear which locates in a further opening in one of said tubular portion and member.

12. A friction clutch according to Claim 11 in which the detent is ring-like and has adjacent free ends which allow the ring to expand to facilitate connection or release of the tubular portion.

13. A friction clutch according to Claim 10, 11 or 12 in which the tubular portion is formed with a plurality of further openings which receive respective ears formed on said detent.

14. A friction clutch according to any of Claims 10 to 13 in which the first said opening receives free end sections of said clip.

15. A friction clutch according to Claim 14 in which said free end sections extend through the first opening and project radially outwardly of the one of said tubular portion and member.

16. A friction clutch according to Claim 14 or 15 in which the first said opening is open in the axial direction to permit entry of said free end section into said opening.

17. A friction clutch according to any of Claims 9 to 16 in which the member of said clutch release mechanism is formed so as to snap fit into engagement with said detent to connect with said hub so that clutch release forces can be applied to the hub via the detent, said member being releasable from said hub by first causing the detent to expand or contract radially and then withdrawing the member from engagement with the detent.

18. A friction clutch according to Claim 17 in which the detent is expanded or contracted by moving its free ends manually.

19. A friction clutch according to any of Claims 9 to 18 in which one of the tubular portion and member is formed with an inclined surface which engages the detent and urges it against the other said tubular portion and member during application of clutch release forces.'

20. A friction clutch constructed and arranged subtstantially as described herein with reference to the accompanying drawings.