GB2197918A

GB2197918A - Clutch cover

Info

Publication number: GB2197918A
Application number: GB08630325A
Authority: GB
Inventors: Luigi Cucinotta; Pietro Caracini
Original assignee: Automotive Products PLC
Current assignee: Automotive Products PLC
Priority date: 1986-09-18
Filing date: 1986-12-18
Publication date: 1988-06-02
Also published as: IT1198026B; IT8621753A1; GB8630325D0; IT8621753A0

Abstract

The clutch cover assembly 2 for a diaphragm spring friction clutch includes a cover 4 formed of moulded synthetic plastics material with a lip formation 12 to locate the fulcrum ring 40 and depression formations 42 to retain the diaphragm spring 32. The plastics material can be a polyester, for example, a polyethylene terephalate. <IMAGE>

Description

Clutch Cover This invention concerns a clutch cover and also a clutch cover assembly.

Clutch cover assemblies are known comprising a cover, a pressure plate, spring means to apply a load to urge the pressure plate in a direction outwardly of the cover, and lever means operable to relieve said load.

Such assemblies can be used to form friction clutches in which the assembly is attached to a driving plate to rotate therewith, and a driven plate beingclampable between the pressure plate and the driving plate when the spring means applies said load.

In a motor vehicle the driving plate may be rotated by the engine of the vehicle and may be the fly-wheel of said engine.

The spring means may be a diaphragm spring acting between a first fulcrum arrangement on the pressure plate and a second fulcrum arrangement on the cover, and the release levers may be radially inwardly directed fingers extending from a surrounding annular Belleville portion of the spring.

The known covers are formed of metal, for example steel, usually pressed to the desired shape which is frequently a dish shape. Often the metal pressing operation consists of several stages before the desired shape is attained.

Also being of metal, the covers are relatively heavy and thus have a correspondingly high moment of inertia.

An object of the invention is to provide a cover which can be relatively light in weight and obviates the need for metal pressing operations.

According to a first aspect of the invention a cover for a friction clutch is formed substantially of synthetic plastics material.

The cover may be formed between mould halves by a plastics moulding technique.

The plastics material may be a polyester material. The plastics material may be a polyethylene terephalate otherwise known as PET.

The cover may be integrally formed with a formation arrangement for radially retaining a fulcrum ring. Also the cover may be integrally formed with a formation arrangement for radially retaining a diaphragm spring.

According to a second aspect of the invention a cover assembly for a friction clutch comprises a cover formed according to the first aspect, a pressure plate, spring means to apply a load to urge the pressure plate in a direction outwardly of the cover, and means operable to relieve said load.

Each aspect of the invention will now be further described, by way of example, with reference to the accompanying drawing in which: Fig.l is a plan view of a clutch cover formed according to the first aspect of the invention included in a cover assembly formed according to the second aspect for a friction clutch; Fig.2 is a section on line II - II in Fig.l; Fig.3 is a fragmentary view along arrow III in Fig.l, and Fig.4 is a section on line IV - IV in Fig.l In the drawing a cover assembly for a friction clutch is shown at 2. The clutch comprising the assembly 2 will be a pull-type clutch and can be used in a motor vehicle to transmit rotary motion from the engine of the vehicle to a gearbox.

The assembly 2 comprises a dish-shaped cover 4 centred on axis X and having at its periphery an interuped rim flange 6 at an axial front end of the cover from which flange the cover has a side wall comprising a cylindrical part 8 extending into a frusto - conical part 10 converging towards the axial rear end at which the cover has an annular inturned lip 12.

The cover 4 is formed of synthetic plastics.

The plastics material can be thermosetting polyester material. For example, the plastics material can be a polyethylene terephalate (PET). If desired the polyethylene terephalate can be a glycol modified polyethylene terephalate (PETG). The cover 4 can be moulded by a plastics material moulding technique comprising introducing the plastics material into a mould cavity between mould halves.

In the side wall of the cover 4 through windows 14 are provided at spaced intervals coinciding with the interuptions in the rim flange 6. Within the cover is an annular pressure plate 16 which can be of cast metal. The pressure plate has peripheral lugs 18 each extending through a respective said window 14. Each lug 18 is rivetted at 20 to a corresponding, resilient, drive/release strap 22 rivetted at 24 to an axially set-back or step portion 26 of the rim flange 6 adjacent to the corresponding window 14. A corner of each step portion 26 is blanked off by an integral and substantially triangular reinforcing bracket portion 28 (Fig.3) extending axially and circumferentially to reinforce and support each step-portion 26 against forces thereon due to the said strap 22 being secured to the step by the rivet 24.An annular fulcrum arrangement 30 on the pressure plate is urged in direction A outwardly of the cover 4 by the load thereon exerted by a circumferental Belleville portion 32 of a diaphragm spring 34 having integral release levers formed by radial fingers 36 separated by slots 38. Near its outer periphery the diaphragm spring 34 bears on a metal fulcrum ring 40 retained against substantial radial movement with respect to axis X by the lip 12 which is inturned into the cover 4 from the rear. Part 10 of the cover is also integrally formed with rectangular depressions forming formations 42 inside the cover to radially retain the diaphragm spring 34 against substantial radial movement thereof. The rim flange 6 has axially set-back portions 44 to any of which a balance rivet 46 (Fig.4) may be attached.

In use the clutch cover assembly is secured to a rotatably driven counter-pressure plate (not shown) for example a fly-wheel by bolts through holes 48 in the rim flange 6. A clutch driven plate (not shown) is clamped against the counter-pressure plate by the pressure plate 16 urged by the diaphragm spring 34. To release the driven plate, the load of the diaphragm spring is relieved by a pull in direction B on finger tips 50.

Claims

1. A cover for a clutch, said cover being formed substantially of synthetic plastics material.

2. A cover as claimed in Claim 1, formed by moulding the plastics material.

3. A cover as claimed in Claim 1 or Claim 2, in which the plastics material is a polyester.

4. A cover as claimed in Claim 1 or Claim 2, in which the plastics material is a polyethylene terephalate.

5. A cover as claimed in any one preceding claim, said cover being integrally formed with a formation arrangement for radially retaining a fulcrum ring for a diaphragm spring friction clutch.

6. A cover as claimed in any one of Claims 1 to 4, said cover being integrally formed with a formation arrangement for radially retaining a diaphragm spring for a diaphragm spring friction clutch.

7. A cover assembly for a friction clutch comprising a cover formed according to any one of Claims 1 to 4, a pressure plate, spring means to apply a load to urge the pressure plate in a direction outwardly of the cover, and lever means operable to relieve said load.

8. A cover assembly as claimed in Claim 7, in which said spring means and lever means are formed by a diaphragm spring with radially inwardly directed fingers.

9. A cover assembly as claimed in Claim 8, wherein said cover is formed according to Claim 5, and in which a fulcrum ring interacting with the diaphragm spring is radially retained by said formation arrangment.

10. A cover assembly as claimed in Claim 8, wherein said cover is formed according to Claim 6, and in which said diaphragm spring is radially retained by said formation arrangment.

11. A cover for a clutch as claimed in Claim 1 and substantially as hereinbefore described with reference to the accompanying drawing.

12. A cover assembly for a friction clutch comprising a cover as claimed in Claim 1, and wherein said cover assembly is substantially as hereinbefore described with reference to the accompanying drawing.

13. A clutch including a cover as claimed in any one of Claims 1 to 6 or Claim 11, or including a cover assembly as claimed in any one of Claims 7 to 10 or Claim 12.

14. A motor vehicle having a clutch as claimed in Claim 13.