GB2259126A

GB2259126A - Clutch release bearing assembly having cap on thrust surface

Info

Publication number: GB2259126A
Application number: GB9110525A
Authority: GB
Inventors: Stuart John Sleath
Original assignee: Automotive Products PLC
Current assignee: Automotive Products PLC
Priority date: 1991-05-15
Filing date: 1991-05-15
Publication date: 1993-03-03
Anticipated expiration: 2011-05-15
Also published as: GB9110525D0; GB2259126B

Abstract

A clutch release bearing assembly (10) including a bearing (11) having one race (16) with a thrust surface (22) thereon and a second stationary race (15) by which the bearing (11) is mounted in a support (12). The thrust surface (22) is covered by a protective cap (23) which is a snap fit over the first bearing race (16), and has a detent (26) that snaps into an axial gap (28) between the bearing races (15) (16). <IMAGE>

Description

"Clutch Release Bearing Assembly" This invention relates to clutch release bearing assemblies and in particular to release bearing assemblies for use in automobiles.

A typical clutch release bearing assembly for an automotive clutch incorporates a support which is guided for generally axial movement or by means of a pivotable release lever.

The support normally carries a non-rotating race of a ball bearing while the other race of the bearing is rotatable and is intended for engagement with the clutch to apply an axial release load thereto. With a diaphragm spring clutch the release load is normally applied direct to the inner ends of the fingers of the diaphragm spring. In some installations the ball bearing may be replaced by a different form of rolling element bearing such as a roller bearing.

The release bearing when fitted on a release cover moves in a slight arc as the clutch release load is applied to the spring fingers. Hence there is some slight relative movement between the rotating race of the bearing and the inner ends of the spring fingers.

In order to overcome this mis-alignment problem the non-rotating race can have a layer of PTFE adhered thereto to enable the bearing to move easily during the normal interaction between the bearing and the clutch.

This has given rise to problems because the PTFE layer is removed or falls off during service.

According to the present invention there is provided a clutch release bearing assembly comprising a rolling element bearing having a first bearing race with a thrust surface thereon for applying a load to a clutch and a second bearing race by which the bearing assembly is mounted in a support, wherein the thrust surface is covered by a protective cap which is a resilient snap fit onto the first bearing race.

Preferably the cap has a detent that locates in a gap between the bearing races.

The invention will now be described by way of example and with reference to the accompanying drawings in which, Fig 1 is a cross section view through a clutch 5release bearing assembly according to the invention, Fig 2 is a cross section view of the protective wear cap as fitted to the release bearing of Fig 1.

Fig 3 is an enlarged radial cross section of the wear cap.

With reference to Fig 1 there is illustrated a clutch release bearing assembly 10 which in use is guided for axial movement on a release lever (not shown) pivotted to the clutch housing in a well known manner.

The release bearing assembly 10 comprises a rolling element bearing 11 which is mounted in a support 12 by a 'U' sectioned annular sheet steel sleeve 13. The support 12 has a pair of diamatrically opposed lugs 14 for attachment to a release fork.

The rolling element bearing comprises a stationary inner race 15 and a rotary outer race 16. The stationary race 15 is fixedly mounted on a radially inner axially extending portion 18 of the sleeve 13 which is connected to a radially outer axially extending portion 19 which is fixedly mounted in the support 12. The rotary outer race 16 is spaced from the sleeve portion 19 and has a radially inwardly projecting thrust member 21, having a thrust surface 22 thereon. There is an axial gap 28 on an inner surface of the bearing 11 between the inner edge of the thrust member 21 and stationary bearing race 15.

The thrust surface 22 is covered by a protective wear cap 23.

The wear cap is made from a resilient plastic material preferably a nylon based material such as glass filled nylon, and more preferably a glass filled nylon 4,6, which also contains a PTFE filler. A suitable material is marketed by DSM (UK) Ltd of Redditch under the designation NC003.

The wear cap 23 has a radially outwardly projecting flange 24 that overlies the thrust surface 22 and which on its inner periphery has an axially extending cylindrical portion 25.

The cylindrical portion 25 has an axially outwardly projecting annular rib 26 thereon.

The rib 26 is a snap fit into the gap 28 on the inner surface of the bearing 11, and forms a detent to prevent any removal of the wear cap from the bearing 11.

Because the cap 23 snaps into the gap 23 between the bearing races, it also helps prevent dirt from entering into the bearing race itself.

Claims

1. A clutch release bearing assembly comprising a rolling element bearing having a first bearing race with a thrust surface thereon for applying a load to a clutch and a second bearing race by which the bearing is mounted in a support, wherein the first surface is covered by a protective cap which is a resilient snap fit onto the first bearing race.

2. A clutch release bearing assembly as claimed in Claim 1 wherein the thrust surface is located on a radially extending portion of the first bearing race, there being an axial gap between said radial portion and the second bearing race, and the cap has a detent thereon that snaps into said axial gap.

3. A clutch release bearing assembly as claimed in Claim 1 dr Claim 2 whereon the first bearing race is a radially outer race and the radially extending portion extends inwardly therefrom, and said gap is located on the radially inner side of the bearing.

4. A clutch release bearing assembly as claimed in any one of Claims 1 to 3 wherein the second bearing race is mounted onto the support through a sleeve which surrounds the two races.

5. A clutch release bearing assembly as claimed in Claim 2, wherein the cap has an axially extending cylindrical portion having a radially extending projecting annular ribs thereon which forms the detent.

6. A clutch release bearing assembly as claimed in any one of Claims 1 to 5 wherein the cap is formed from a glass filled nylon material.

7. A clutch release bearing assembly substantially as described below herein and as shown in the accompanying drawings.