GB2215422A

GB2215422A - Clutch release bearing assembly with sleeve for protecting shaft

Info

Publication number: GB2215422A
Application number: GB8804413A
Authority: GB
Inventors: William George Munson
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1988-02-25
Filing date: 1988-02-25
Publication date: 1989-09-20
Also published as: GB8804413D0

Abstract

A clutch release bearing 22 slides on a shaft 14. A sleeve 28 surrounds the shaft and provides a seat for the bearing so that the sliding movement of the bearing does not result in damaging wear to the shaft. The sleeve preferably grips around the shaft, has a better wear resistance than the shaft and has a longitudinal split to give resiliency. The sleeve is preferably of spring steel with inwardly bent tangs for gripping the shaft. <IMAGE>

Description

Clutch release bearing assembly This invention relates to a clutch release bearing assembly for the driveline clutch in a motor vehicle. The invention is particularly suitable for use where the clutch release bearing slides on a stub shaft of an alloy of aluminium or other light metal.

It is desirable to use light metal components wherever possible in motor vehicles in order to reduce the overall vehicle weight.

According to the invention there is provided a clutch release bearing assembly comprising a bearing support shaft, a sleeve mounted on the shaft and a release bearing axially slideable on the sleeve.

The sleeve is preferably constructed so that it grips around the shaft.

The sleeve is preferably of a material which has a better wear resistance than the support shaft and may be of spring steel.

The sleeve may have a longitudinal split. It can then have a relaxed internal diameter smaller than the diameter of the shaft so that it can be expanded over the shaft to grip the shaft when in place. The sleeve can preferably also be compressed to take up a circumference smaller than its normal relaxed circumference.

The axial length of.the sleeve is preferably equal to the axial length of the bearing plus the length of the axial movement of the bearing between the "clutch engaged" and "clutch disengaged" positions. The sleeve may be constructed so that the friction between the sleeve internal diameter and the shaft is greater than that between the bearing and the sleeve so that the sleeve is normally stationary when the bearing moves to engage or disengage the clutch. However as the clutch plate facings wear, the sleeve can slide along the shaft to compensate.

In order to produce the correct frictional conditions, the sleeve may have inwardly directed projections such as tangs or pimples which bear against the surface of the shaft and increase the grip of the sleeve on the shaft.

The use of a sleeve as set forth above avoids undesirable wear arising on the external circumference of the shaft.

The sliding movement instead takes place between the bearing and the sleeve, and the sleeve can be made of a suitably resistant material.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which; Figure 1 is a side view showing a section through a clutch housing which includes a release bearing assembly in accordance with the invention; Figure 2 is an elevation of a sleeve for use in the assembly of Figure 1; and Figure 3 is an end view of the sleeve of Figure 2.

The clutch unit shown in Figure 1 is largely conventional, and most of the components will be familiar to those skilled in the art. The housing 10 is formed at the left hand end of a gear box housing 12. The internal mechanism of the gearbox is not shown, neither is the final drive shaft from the gearbox which leaves the housing 12 axially and passes through a central bore in a bearing support shaft 14 before engaging with a drive transmitting component on the clutch pressure plate 16. The pressure plate 16 has a friction facing 18 which can be driven towards and away from a corresponding face of a transmission shaft (which is also not itself shown).

Movement of the pressure plate is controlled by spring fingers 20 of a diaphragm spring which act at one end against the pressure plate and at the other end against a release bearing 22. The other side of the release bearing is acted upon by an actuating lever which is pivoted on a fulcrum at 24 and enters the housing 10 through a window 26.

Thus far, the components described are largely conventional.

The bearing support shaft 14 does not rotate and is present to provide a support for the release bearing 22 which moves axially along the shaft to operate the clutch.

Between the bearing and the shaft is fitted a sleeve 28.

This sleeve is shown in more detail in Figures 2 and 3.

It is cylindrical with an internal diameter such that it will fit closely around the shaft 14, and an external diameter which provides a good seat for the bearing 22 whilst allowing the bearing to move axially. At each end of the sleeve there is a shoulder 30, 32 and these shoulders will limit axial movement of the bearing on the sleeve. The shoulders need not be continuous; they may be interrupted shoulders or merely spaced lugs around the circumference. In Figure 1 the necessary axial movement for clutch operation is shown at 34, and the overall length of the sleeve 28 is equal to the axial supported length of the bearing 22 plus the operating distance 34.

In normal operation, when the bearing 22 is moved to the left in Figure 1 it will move no further than the left hand shoulder 30 and the sleeve itself will not be displaced. However as the friction facing 18 wears, the sleeve may move axially along the surface of the shaft 14 to compensate for the wear.

Internally projecTing tangs 38 or other projections can be pressed out o the material of the sleeve in order to increase the friction between the sleeve interior and the shaft 14.

As can be seen in Figure 3, the sleeve has a longitudinal slit 40, and this allows the sleeve to be compressed sufficiently to be inserted into the wall of the release bearing before the release bearing and the sleeve are together placed over the shaft 14.

As a result of the presence of the sleeve, the backwards and forwards sliding movement of the release bearing 22 acts against the sleeve rather than against the shaft and reduces the likelihood of damaging wear of the shaft 14.

Claims

1. A clutch release bearing assembly comprising a bearing support shaft, a sleeve mounted on the shaft and a release bearing axially slideable on the sleeve.

2. An assembly as claimed in Claim 1, wherein the sleeve grips around the shaft.

3. An assembly as claimed in Claim 1 or Claim 2, wherein the sleeve is of a material which has a better wear resistance than the support shaft.

4. An assembly as claimed in any preceding claim, wherein the sleeve is of spring steel.

5. An assembly as claimed in any preceding claim, wherein the sleeve has a longitudinal split and has a relaxed internal diameter smaller than the diameter of the shaft so that it can be expanded over the shaft to grip the shaft when in place.

6. An assembly as claimed in any preceding claim, wherein the axial length of the sleeve is equal to the axial length of the bearing plus the length of the axial movement of the bearing between the "clutch engaged" and "clutch disengaged" positions.

7. An assembly as claimed in any preceding claim, wherein the sleeve is constructed so that the friction between the sleeve internal diameter and the shaft is greater than that between the bearing and the sleeve so that the sleeve is normally stationary when the bearing moves to engage or disengage the clutch.

8. An -assembly as claimed in any preceding claim, wherein the sleeve has inwardly directed tangs which bear against the surface of the shaft.

9. A clutch release bearing assembly substantially as herein described with reference to the accompanying drawing.