GB2201479A

GB2201479A - A friction clutch for a vehicle

Info

Publication number: GB2201479A
Application number: GB08718763A
Authority: GB
Inventors: Luigi Cucinotta
Original assignee: Automotive Products PLC
Current assignee: Automotive Products PLC
Priority date: 1987-02-27
Filing date: 1987-08-07
Publication date: 1988-09-01
Anticipated expiration: 2007-08-07
Also published as: AU599247B2; AU1847988A; GB8718763D0; IT1202593B; GB2201479B; IT8719521A0

Abstract

The clutch includes a release mechanism comprising a first member 17, a second member 18 and a detent 33 arranged to locate the first member relative to the second member on assembly by moving the first member in one direction relative to the second member whereby a clutch release force subsequently applied to said first member in an opposite direction will be transmitted to said second member to release the clutch. The detent 33 is releasable by urging said first member 17 further in said one direction relative to said second member 18 so that the first and second members can thereafter be separated. A clutch release member 19 is provided for applying said clutch release force arranged in the path of the first member 17 to inhibit accidental release movement of the first member relative to said second member 18 in said one direction. <IMAGE>

Description

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 pull type comprising a first member, a second member, and a detent arranged to locate the first member relative to the second member on assembly by moving the first member in one direction relative to the second member whereby a clutch release force subsequently applied to said first member in an opposite direction will be transmitted to said second member to release the clutch, said detent being releasable by urging said first member further in said one direction relative to said second member so that the first and second members can thereafter be separated.

Should the detent become accidentally released when the vehicle in which the clutch is installed is being driven, the clutch would be disengageable and an object of the present invention is to provide a clutch in which that particular problem is substantially avoided.

According to the invention there is provided a friction clutch for a vehicle which includes a clutch release mechanism comprising a first member, a second member, a detent arranged to locate the first member relative to the second member on assembly by moving-the first member in one direction relative to the second member whereby a clutch release force subsequently applied to said first member in an opposite direction will be transmitted to said second member to release the clutch, said detent being releasable, by urging. said first member further in said one direction relative to said second member so that the first and second members can thereafter by separated and a clutch release member for applying said clutch release force arranged in the path of the first member to inhibit accidental release movement of the first member relative to said second member in said one direction.

Preferably the clutch release member may be mounted on a housing for the clutch, which housing is detachable to enable the clutch release member to be moved out of the path of the first member and permit the first member subsequently to be moved relative to the second member in said one direction.

The housing may be a bell-type housing mounted on an engine of the vehicle, the only way in which the detent can be released being by first removing the housing from the engine so as to move the release member out of the path of the first member.

Preferably, the clutch release member locates between said first and second members, e.g. between projections on said members.

The clutch release member may transmit clutch release force through the projection on the first member.

Preferably, the clutch release member is pivotally mounted on said housing.

The clutch release member may comprise spaced apart fingers for location e.g. between said first and second members at diametrically opposite positions.

The detent may comprise a resilient ring which locates between retention surfaces on said first and second members to transmit clutch release force between said members and which deforms to clear at least one of the retention surfaces when released.

In such a case, bias means may be arranged between the first and second members to urge said retention surfaces of the first and second members normally into engagement with said detent.

Preferably, the second member is axially fast with a clutch release bearing through which clutch release forces are transmitted.

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 cross section of a friction clutch in accordance with the invention, and Fig. 2 is a side view of part of the clutch of Fig. 1 looking in the-directions of arrow II in Fig. 1.

A clutch pressure plate 10 is retractable by means of a clutch release mechanism 11 to release a clutch driven plate 12.

Clutch release effected by applying a force in direction A to a release plate 12 for a clutch spring 14 through a short hollow shaft 15, a clutch release bearing 16 and first and second clutch release members 17, 18. The releasing force is applied by spaced fingers 19 rotatably fast with a shaft 20 pivotally mounted adjacent each end (one end only being showing in Fig. 1) on a bell housing 22 attached to an engine 21 by bolts B. One end of the shaft 20 is rotatably fast with a lever 23 to which clutch release force can be applied by a hydraulic actuator or cable (not shown).

Looking at the clutch release mechanism 11 in greater detail, the first member 17 comprises a tubular section 24 which houses a bearing bush 25 slidable along a hollow cylindrical extension 26 of a gearbox 27. A derive input shaft (not shown) rotatably fast with the clutch driven plate 12 extends through the extension 26 in known manner to serve as a drive input shaft for the gearbox. The tubular section 24 has an annular flange 28 at its right hand end, as viewed in Fig. 1, which is formed with a cylindrical -wall 29 and two radial abutments 30. The tubular section 24 is formed with a peripheral groove 32 in which a resilient split ring 33 (constituting the aforesaid detent) is locatable.The tubular section 24 carries a sleeve 34 which prior to assembly of the clutch release mechanism, is used to return the ring 33 in a compressed state the groove 32 in a manner similar to that shown in Fig. 13 of our EP No. 0110602A3.

The unstressed inner diameter of the ring 33 is equal to or greater than the outer diameter of the tubular section 24.

The second member 18 includes a cylindrical section 35 formed with first and second internal steps 36,37 and being slidable axially on the tubular section 24. The cylindrical section 35 has an annular shoulder 38 from which extends a rim 39.

The rim 39 is formed with an external circumferential projection 40 and an internal groove 41 which receives a circlip 42.

The circlip retains axially within the rim 39 an outer race 43 of the clutch release bearing 16. An inner race of the bearing 16 is formed by the hollow shaft 15. The clutch spring 14 is sandwiched between the release plate 13 and a Belleville washer 44 on the shaft 15. A grease seal 45 is sandwiched between the outer race 43 and the annular shoulder 38 and a compression spring 46 is positioned between the annular flange 28 and the annular shoulder 38.

To assemble the clutch release mechanism, the bell housing 22 is initially detached from the engine and the tubular section 24 of the first member 17 is inserted into the cylindrical section 35 of the second member 18. The first member 17 is moved manually left'rids against the bias of spring 46 so that the second member 18 pushes the sleeve 34 clear of the groove 32 thereby enabling the ring 36 to expand against the second member. Such movement of the first member 17 is continued until the ring 36 snaps into the first step 36 as shown in Fig. 1 so that the ring lies partly in the groove 32. The spring 46 biases the first and second members in opposite axial directions whereby the ring 33 is trapped in the position shown between the left hand radial surface of the groove 32 and the right hand surface of step 36 (constituting the aforesaid retention surfaces).The bell housing 22 is then moved into position and the fingers 19 are simultaneously located with axial clearance C between the abutments 30 on the first member 17 and the circumferential projection 40 on the second member 18. The fingers 19 lie substantially against the cylindrical wall 29 of the first member and a circumferential ledge 47 of the second member.

To release the clutch, the shaft 20 is rotated by lever 23 so that the fingers 19 apply clutch release force in direction A to the first member 17 via the abutments 30. The force is transmitted to the second member 18 through the ring 36 and from thence to the spring 14.

To dismantle the clutch release mechanism, the bell housing 22 is first removed from the engine so as to withdraw the fingers 19 from between the first and second members 17,18. The first member is then urged to the left relative to the second member 18 against the bias of spring 46 by a distance (greater than clearance C) sufficient to enable the ring 36 to snap into the second step 37 clear of groove 32. The first member 17 is then released and the spring 46 urges the first member to the right thereby assisting in the separation of the first and second members. Once the members have been separated, the ring 36 can be recovered.

It will be appreciated that sufficient movement of the first member towards the second member to release the ring 30 cannot take place while the fingers 19 are in situ as in Fig. 1 so that release of the detent ring 36 cannot occur without first removing the bell housing 22. Such an arrangement enhances the reliability of the clutch release mechanism whilst retaining simplicity in construction and in assembly and dismantling procedures.

Claims

1. A friction clutch for a vehicle which includes a clutch release mechanism comprising a first member, a second member, a detent arranged to locate the first member relative to the second member on assembly by moving the first member in one direction relative to the second member whereby a clutch release force subsequently applied to said first member in an opposite direction will be transmitted to said second member to release the clutch, said detent being releasable by urging said first member further in said one direction relative to said second member so that the first and second members can thereafter be separated and a clutch release member for applying said clutch release force arranged in the path of the first member to inhibit accidental release movement of the first member relative to said second member in said one direction.

2. A friction clutch according to Claim 1 in which the clutch release member is mounted on a housing for the clutch, which housing is detachable to enable the clutch release member to be moved out of the path of the first member and permit the first member subsequently to be moved relative to the second member in said one direction.

3. A friction clutch according to Claim l or 2 in which the clutch release member locates between said first and second members.

4. A friction clutch according to Claim 3 in which the clutch release member locates between projections on said first and second members.

5. A friction clutch according to Claim 4 in which the clutch release member transmits clutch release force through the projection on the first member.

6. A friction clutch according to any preceding claim in which the clutch release member is pivotally mounted on said housing.

7. A friction clutch according to any preceding claim in which the clutch release member comprises spaced apart fingers for co-operation with said first member at diametrically opposite positions.

8. A friction clutch according to any preceding claim in which the detent comprises a resilient ring which locates between retention surfaces on said first and second members to transmit clutch release force between said members and which deforms to clear at least of the retention surfaces when released.

9. A friction clutch according to Claim 8 in which bias means is arranged between the first and second members urge the said retention surfaces of the first and second members normally into engagement with said detent.

10. A fricton clutch according to any preceding claim in which the second member is axially fast with a clutch release bearing through which clutch release forces are transmitted.

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