GB2305484A

GB2305484A - Clutch assembly having a spring clip connecting an actuation member and a clut ch release member

Info

Publication number: GB2305484A
Application number: GB9603638A
Authority: GB
Inventors: David Robertson Grant; Robert Leslie Smith
Original assignee: LIPE Ltd
Current assignee: LIPE Ltd
Priority date: 1995-02-21
Filing date: 1996-02-21
Publication date: 1997-04-09
Anticipated expiration: 2016-02-21
Also published as: GB2305484B; GB9503330D0; GB9603638D0

Abstract

A clutch actuation ring 23 is connected to a clutch release bearing by a spring clip 24 which has a circular section 35 and two end portions 36,37. One of the end portions 36 has a tangentially extending part 41 and an axially extending part 42, the latter facilitating widening of the clip to release the clutch release bearing from the actuation ring 23. The other end portion 37 also has an axially extending portion 44 which engages with a slot 19 between adjacent fingers of the diaphragm spring to limit relative rotation between the clip and the diaphragm. The circular part 35 of the clip preferably has an outwardly extending portion 45 received in a slot in the actuation ring 23. The radially extending parts 36,37 of the clip preferably locate in a respective chordal slot 48,49 of the actuation ring. A retaining ring 50 preferably retains the actuation ring and spring clip on the diaphragm when disengaged from the clutch release bearing.

Description

Title: Clutch Assembly Description of Invention This invention relates to a diaphragm spring friction clutch assembly, hereinafter referred to as a clutch assembly of the kind specified, comprising a diaphragm spring to bias drive and driven clutch members together in torque transmitting relationship, and an actuation ring which is axially movable along an axis to release the clutch, a clutch release member adapted to be moved axially along said axis by a clutch release means and said actuation ring having a first annular shoulder facing in one axial direction, said clutch release member having a second annular shoulder facing in the opposite axial direction, and a spring clip disposed between said shoulders and in engagement with each thereof releasably to interconnect the actuation ring and the clutch release member for disengagement of the clutch, wherein the spring clip comprises a substantially circular portion, engaging both annular shoulders, and two end portions, at least one end portion being moveable relative to the other so as to permit of widening of the substantially circular portion, to allow disengagement of the actuation ring and clutch release member.

The clutch release member is typically rotatably mounted relative to the clutch release means, which may be linked to, for example, a clutch pedal operated means, so that axial movement of the clutch release member causes engagement or disengagement of the clutch.

A clutch assembly of the kind specified may further comprise a cover member adapted to be mounted on the drive member such as a vehicle flywheel, a pressure plate mounted to rotate with the cover member, the diaphragm spring applying pressure to the pressure plate to clamp the driven member between the pressure plate and the drive member. The diaphragm spring may have an opening in which the actuation ring is mounted so that axial movement of the actuation ring in said opposite axial direction releases the pressure applied to the pressure plate by the diaphragm spring.

The connection provides a comparatively simple means to interconnect the clutch release member and the actuation ring by way of a "snap fit" type engagement.

In order for release of the actuation ring and the clutch release member, it has previously been necessary to use a tool, or crossed over manually engageable parts on the spring clip must be squeezed together to increase the effective diameter of the generally circular spring clip, for example, as disclosed in UK patent 2212878B. Such a squeezing action is relatively hard to perform.

It is accordingly an object of the present invention to provide a clutch assembly in which separation of the actuation ring and the clutch release member is facilitated and which may be accomplished manually without the need for special tooling and which may be accomplished relatively easily.

According to one aspect of the invention, there is provided a clutch assembly of the kind specified, wherein one of said end portions is adapted to be restrained from rotation about said axis and said other end portion is adapted to be engaged to permit of widening of said substantially circular portion.

Said one end portion may have a first axially extending part and said other end portion may have a second axially extending part, said first and second axially extending parts extending in opposite axial directions.

Said one axial extending part may engage the diaphragm spring of the clutch.

Said one axially extending portion may be engaged in a slot between fingers of the diaphragm spring.

The actuation ring may have a generally axially extending tubular part.

According to a second aspect of the invention, or in the first aspect of the invention, the spring clip may be provided with a co-operation portion adapted to co-operate with the actuation ring to restrain relative axial movement between said co-operation portion of the spring clip and the actuation ring.

Said co-operation portion may comprise a portion of the spring clip which is disposed radially outwards of said substantially circular portion and the actuation ring having a co-operating recess or slot of the actuation ring in which the radially outwardly disposed portion is engaged.

The actuation ring may have a generally axially extending tubular portion and said recess or slot being provided in said tubular portion.

The actuation ring may have an abutment means facing in said opposite axial direction to engage one side of said diaphragm spring, said one side facing in said one axial direction, and at least part of at least one of said end portions being disposed to engage the other side of said diaphragm spring, said other side facing in said opposite axial direction, such that axial movement of the spring clip relative to said actuation ring in said one axial direction is restrained.

According to a third aspect of the invention, or in the first or second aspect of the invention, one of said end portions may extend, transversely to said generally circular portion, through a slot in said actuation ring to restrain relative rotation between the spring clip and the actuation ring and thus between the diaphragm spring and the actuation means.

The actuation ring may have a generally axially extending tubular portion and said slot being provided in said tubular portion.

In any aspect of the invention the tubular portion may have an inwardly directed flange to provide said first annular shoulder.

The tubular portion may have an outwardly directed flange facing in said other axial direction to provide an or the abutment means to abut the spring.

A retaining ring may be provided to engage a surface of said outwardly directed flange which faces in said one axial direction and to engage with a surface of the spring which faces in said opposite axial direction.

The retaining ring may be of generally annular configuration to engage the fingers of the spring and have a plurality of tongues extending axially between the fingers of the spring and having hook portions adapted to engage said other surface of the outwardly extending flange.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, wherein: FIGURE 1 is a side elevation, partly broken away and partly in section of a diaphragm spring friction clutch embodying the invention; FIGURE 2 is a fragmentary end view, in the direction of the arrow X in Figure 1, showing a part of the diaphragm spring of the clutch of Figure 1 together with an actuation ring engaged therewith; FIGURE 3 is a section on the line 3-3 of Figure 2; FIGURE 4 is an axial view of a retaining ring, and FIGURE 5 is a side view of the ring of Figure 4.

Referring to the Figures, there is shown a basically conventional diaphragm spring friction clutch 10 comprising a cover member 11 bolted to a vehicle flywheel 12.

A pressure plate 13 is mounted within the cover member 11 for rotation therewith about an axis 14.

A diaphragm spring 15 acts between the cover member 11 and the pressure plate 13 to bias the pressure plate towards the flywheel so as frictionally to clamp a driven plate 16 between the pressure plate 13 and the flywheel 12.

The pressure plate 13 is held co-axial with the axis 14 by a plurality of straps which extend approximately tangentially or chordally between the cover and the pressure plate in conventional manner.

The diaphragm spring 15 comprises a generally annular outer part 17 and a plurality of radially inwardly directed fingers 18 with generally radial slots 19 therebetween. The fingers 18 define, together, a central aperture 20.

The pressure plate 13 carries a circular in cross-section wire ring 21 in a circumferentially extending groove 22. The ring 21 acts as a fulcrum against which the diaphragm spring 15 bears and about which dishing of the diaphragm spring is varied during clutch actuation in conventional manner.

The aperture 20 provided by the fingers 18 receives a clutch release actuation ring 23 made of a sheet metal pressing and comprising an axially extending tubular portion 23a having an inwardly directed flange 23b at one end and an outwardly extending flange 23c at the other end.

A clutch release member 24 of sleeve configuration is releasably engageable with the actuation ring 23 as hereinafter to be described. The clutch release member 24 is connected in conventional manner by a ballbearing 25 to a tubular portion 26 provided with ears 27 which are engaged by a forked end 28 of a pivoted lever 29 of a clutch release means 30 of conventional kind.

Operation of the clutch release means 30 causes the lever 29 to pivot to cause the ears 27 to be moved to the right in Figure 1 and so move the actuation ring 23 to the right in Figure 1 and thus cause the inner ends of the fingers 18 to be moved to the right and so release the clutch.

The releasable connection between the clutch release member 24 and the actuation ring 23 will now be described.

The clutch release member 24 has a nose part 31 which has an external frusto-conical surface 32 which at its larger diameter end has a generally annular shoulder 33L A similar shoulder 33h is provided on the inwardly directed flange 23b of the actuation ring 23. In order to retain the nose part 31 in releasable retention with the actuation ring 23, a spring clip 34 is provided.

The spring clip 34 is made by bending from wire of circular cross-section and comprises a part 35 which is generally circular in a plane normal to the axis 14.

The circular part 35 has end portions 36, 37, each of which extends in a respective plane 38, 39 which is substantially radial to the axis 14, and are axially inclined as shown at 40 in Figure 3 so as to be axially offset with respect to a plane defined by the circular part 35.

At the outer end of the generally radially outwardly extending portion 36 the clip 34 has a tangentially extending part 41 and at the free end thereof an axially extending part 42 which extends in a direction away from the flywheel 12.

Similarly the other generally radially outwardly extending portion 37 has a tangentially extending portion 43 but which extends in the opposite direction to the tangentially extending portion 41 and has at the free end thereof an axially extending portion 44 which extends towards the flywheel 12, i.e. in the opposite direction to the axially extending portion 42. The axially extending portion 44 is disposed in a slot 19 between adjacent fingers 18 so as to prevent rotation of the clip 34 about the axis 14 although limited rotation due to clearance between the portion 44 and the fingers 18 can take place.

Diametrically opposite to the generally radially extending portions 36, 37 the circular part 35 of the clip has a radially outwardly displaced co-operation portion 45 which is received in a generally diametrically extending slot 46 provided in a wall part 47 of the tubular portion 23a of the actuation ring 23.

The generally radially extending parts 36, 37 of the spring clip extend through a respective chordal slot 48, 49 formed in the wall part 47 of the actuation ring 23. The slot 48 for the radially outwardly extending portion 36 is of greater chordal extent than the slot 49 provided for the radially outwardly extending portion 37. The slot 49 is relatively narrow in the said circumferential direction to prevent or to restrict relative rotation between the clip and the actuation ring 23 to a predetermined limited extent.

A retaining ring 50 is provided to retain the actuation ring 23 and spring clip 34 in place on the diaphragm spring when disengaged from the clutch release member 24. The spring 50, as best shown in Figures 4 and 5, comprises a body part 51 which is of an annular shape when viewed in an axial direction and which is of wavy configuration when viewed in a side elevation as shown in Figure 4. Extending axially from the body 51 are a plurality, in the present example 9, fingers 52 which have a hook shaped configuration at their free ends as shown at 53.

As shown in Figures 2 and 3 the retaining spring 50 is disposed with the annular body adjacent the side of the diaphragm spring 15 which faces in said opposite axial direction and with the fingers 52 extending through slots 19 between the fingers 18 of the spring 15. The hook formations 53 hook over the periphery of the outwardly extending flange 23c on the side thereof which faces in said one axial direction so that the opposite face of the flange which faces in said opposite axial direction is held adjacent to or in abutment with the fingers 18 of the spring 15. The corrugated configuration of the annular body 51 provides the clip with resilience since the "peaks" 54 of the corrugations are adapted to engage the fingers 18 whilst the "troughs" 55 from which the fingers 52 extend are spaced from the fingers of the diaphragm spring.

In use, when it is desired to assemble the clutch release member 24 with the actuation ring 23 the nose part 31 is pushed axially in the direction Al so that the taper provided by the frusto-conical surface 32 causes the circular part 35 of the spring clip 34 to expand elastically until it snaps behind the shoulder 33aL At the same time the spring clip is interposed between the shoulders 33a and 33b so as to prevent passage of the nose part 31 outwardly of the actuating ring 23 in the direction A2. Consequently, axial movement of the clutch release member 24 caused by the lever 29 is communicated through the spring clip 34 to the actuation ring 23 and hence to the fingers 18 to disengage the clutch in conventional manner.

When it is desired to release the nose part 31 from the actuation ring 23 it is simply necessary. to move the axially extending part 42 in a generally tangential direction relative to the axis 14 to increase the diameter of the circular part 35 so as to permit the shoulder 33a to pass through the circular part 35 of the spring clip. Such generally tangential movement of the axially extending part 42 can be simply achieved manually, either by directly grasping the part 42 with the fingers by an operative, or by an operative pressing on the part 42 directly with a digit or with a suitable tool such as a lever. Single handed operation only is required since the force needs to be applied to the part 42 only in a single direction because the other axially extending part 44 is anchored by virtue of its engagement in the slot 19.

The relatively greater width of the slot 48 permits of such generally tangential movement of the axially extending part 42 and the associated radially extending part 36, whilst the relatively narrow width of the slot 49 is all that is required since the radially extending part 37 and associated axially extending part 44 remain fixed relative to the diaphragm spring 15 and the actuation ring 23.

The radially outwardly displaced co-operation portion 45 retains the spring clip 34 to prevent or limit axial movement relative to the actuation ring 23 during introduction of the nose part 31 through the circular part 35 of the clip 34.

This may be aided by engagement of the radially extending parts 37 with the diaphragm spring.

The anchoring of the spring clip relative to the diaphragm spring by engagement of the axially extending part 44 in a slot 19 permits of relatively easy "one finger" operation to release the nose portion from the actuation ring.

The relatively narrow slot 49 prevents rotation of the actuation ring 23 relative to the diaphragm spring since the slot 49 prevents rotation between the actuation ring 23 and the spring clip 34 whilst rotation of the spring clip 34 relative to the diaphragm spring is prevented by the hereinbefore mentioned engagement of the axially extending part 44 in the slot 19, thereby reducing wear on the diaphragm fingers. Of course, clearance between the part 44 and the sides of the slot can allow limited rotation to occur.

In this specification the term "restrain rotation" is intended to cover both prevention of any rotation and movement whatsoever and the prevention of more than a small amount of rotational movement. Usually the small amount will be a few degrees.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A clutch assembly of the kind specified, wherein one of said end portions is adapted to be restrained from rotation about said axis and said other end portion is adapted to be engaged to permit a widening of said substantially circular portion.

2. A clutch assembly according to Claim 1 wherein said one end portion has a first axially extending part and said other end portion has a second axially extending part, said first and second axially extending parts extending in opposite axial directions.

3. A clutch according to Claim 2 wherein said one axially extending part is engaged with the diaphragm spring of the clutch.

4. A clutch assembly according to Claim 3 wherein said one axially extending portion is engaged in a slot between fingers of the diaphragm spring.

5. A clutch assembly according to any one of the preceding claims wherein the spring clip is provided with a co-operation portion adapted to cooperate with the actuation ring to restrain relative axial movement between said co-operation portion of the spring clip and the actuation ring.

6. A clutch assembly of the kind specified wherein the spring clip is provided with a co-operation portion adapted to co-operate with the actuation ring to restrain relative axial movement between said co-operation portion of the spring clip and the actuation ring.

7. A clutch assembly according to Claim 5 or Claim 6 wherein said cooperation portion comprises a portion of the spring clip which is disposed radially outwardly of said substantially circular portion and the actuation ring having a cooperating recess or slot in which the radially outwardly disposed portion is engaged.

8. A clutch assembly according to Claim 7 wherein the actuation ring has a generally axially extending tubular portion and said recess or slot being provided in said tubular portion.

9. A clutch assembly according to Claim 5 or Claim 6 wherein the actuation ring has an abutment means facing in said opposite axial direction to engage one side of said diaphragm spring, said one side facing in said one axial direction, and at least part of at least one of said end portions being disposed to engage the other side of said diaphragm spring, and said other side facing in said opposite axial direction, such that axial movement of the spring clip relative to said actuation ring in said one axial direction is restrained.

10. A clutch assembly according to any one of the preceding claims wherein one of said end portions extends transversely to said generally circular portion, through a slot in said actuation ring to restrain relative rotation between the spring clip and the actuation ring and thus between the diaphragm spring and the actuation means.

11. A clutch assembly of the kind specified wherein one of said end portions extends transversely to said generally circular portion, through a slot in said actuation ring to restrain relative rotation between the spring clip and the actuation ring and thus between the diaphragm spring and the actuation means.

12. A clutch assembly according to Claim 10 or Claim 11 wherein the actuation ring has a generally axially extending tubular portion and said slot is provided in said tubular portion.

13. A clutch assembly according to any one of the preceding claims wherein the tubular portion has an inwardly directed flange to provide said first annular shoulder.

14. A clutch assembly according to Claim 12 or Claim 13 wherein the tubular portion has an outwardly directed flange facing in said other axial direction to provide the abutment means to abut the spring.

15. A clutch assembly according to Claim 8, 12 or 13 when dependent upon Claim 8 or Claim 12 wherein the tubular portion has an outwardly directed flange facing in said other axial direction to provide an abutment means to abut the spring.

16. A clutch assembly according to Claim 14 or Claim 15 wherein a retaining ring is provided to engage a surface of said outwardly directed flange which faces in said one axial direction and to engage with a surface of the spring which faces in said opposite axial direction.

17. A clutch assembly according to Claim 16 wherein the retaining ring is of generally annular configuration to engage the fingers of the spring and has a plurality of tongues extending axially between the fingers of the spring and having hook portions adapted to engage said other surface of the outwardly extending flange.

18. A clutch assembly substantially as herebefore described with reference to the accompanying drawings.

19. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.