GB1583606A - Clutch release assembly - Google Patents

Description

(54) CLUTCH RELEASE ASSEMBLY (71) We, AUTOMOTIVE PRODUCTS LIMI TED, a British Company of Tachbrook Road, Leamington Spa, Warwickshire, CV31 3ER, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement The invention relates to clutch release assemblies.

A typical clutch release assembly for an automotive clutch incorporates a release member which is guided for generally axial movement either on an axially extending guide member or by means of a pivotable release lever. The release member 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, It is difficult to establish accurate axial alignment between the guide member for the release bearing assembly and the clutch itself.

Mis-alignment can lead to a variety of problems including premature wear of diaphragm spring fingers and frictional heating leading to a short life for the ball bearing.

In order to overcome the mis-alignment problem the ball bearing can be mounted in the release member for limited radial movement. Then some control of the radial position of the ball bearing with respect to the release member is desirable in order to establish and maintain alignment between the bearing and the clutch.

According to the invention there is provided a clutch release assembly for a diaphragm spring clutch, the assembly comprising a diaphragm spring having radial fingers co-axially supporting and locating a guide ring, a non-rotatable axially movable release member and a rolling element bearing having a rotary race arranged to apply an axial release load to the diaphragm spring and a non-rotatable race radially adjustably mounted on the release member, to allow axial alignment between the bearing and the diaphragm spring, the rotatable race and guide ring having mutually co-operating guide surfaces, one of which has a tapered lead-in whereby the release bearing is axially aligned with the diaphragm spring as the rotary race is brought into engagement with guide ring by operation of the release member, the guide ring comprising two annular parts, respectively a location element fixed between adjacent fingers of the diaphragm spring and a guide element fixed to the location element and axially aligned with the diaphragm spring.

The two parts of the guide ring may, for example be ultra-sonically welded together.

An embodiment of the invention will now be described with reference to the accompanying drawing which is: A diagrammatic cross-sectional view through a clutch release assembly according to the invention.

The clutch release assembly incorporates an annular release member 11 which is guided for axial movement on a sleeve 12 which does not form part of the assembly and is shown in chain-dotted outline. The sleeve 12 may, for example, be supported on a gearbox casing and may be arranged to surround the gearbox input shaft. The release member incorporates a radial flange 13 which has an annular forward facing boss 14 against which the non rotating race 15 of a ball bearing 16 is located.

An annular pressing 17 is secured to the outer periphery of the outer flange 13 by means of a bent over lip 18. An axially extending portion 19 of the pressing 17 carries an inwardly directed forward flange 21 which locates the non rotating race 15 with respect to the flange 13. Although the race is held between the boss 14 and flange 21 against movement in an axial direction, there is in practice a small clearance which allows the race 15 to move freely in a radial direction with the imits controlled by the central part of the release member 11 or by the pressing 17.

The bearing 16 also incorporates a rotary race 23 which is guided with respect to the race 15 by a series of balls 24. The race 23 has an annular forward extension which terminates in a curved clutch engagement surface 37 which is intended to bear against the inner part of the diaphragm spring fingers of a diaphragm spring clutch.

One diaphragm spring finger 25 is shown diagrammatically in the drawing in engagement with surface 37. The diaphragm spring supports a guide ring 27 which is constituted by a location element 28 and a guide element 29. The location element 28 is in the form of an annular ring with a cruved annular face 31 for engagement with the diaphragm spring fingers and with a series of projections 32 which extend through the gaps between adjacent fingers and hence locate the location element positively against any radial movement with respect to the diaphragm spring.

The guide element 29 is secured by means such as ultrasonic welding to the ends of the projections 32 on the opposite side of the diaphragm spring from the ring of the location element 28. The guide element also incorporates a curved face 33 which engages the diaphragm spring fingers and together with the curved face 31 permits relative angular movement between the fingers 25 and the guide ring 27. The guide element 29 has an inner annular guide surface which has a generally axial forward portion 34 and a tapered lead-in 35. It is important for the guide surface 34 and 35 to be accurately in axial alignment with the axis of rotation of the clutch as a whole.

When the clutch and the release bearing are assembled together, which normally occurs when a gearbox is secured to an engine and clutch combination, the tapered lead-in 35 co-operates with the curved clutch engagement surface 37 of the release bearing so that the release bearing is moved radially if necessary to bring it into accurate axial alignment with the guide surface 34 and 35 and the axis of clutch rotation. The axial forward portion 34 of the guide surface ensures that the coaxial relationship is retained during small axial movement between the guide ring and the release bearing. Such axial movement may in part be a small clearance when the clutch is released but also includes movement to accommodate inclination of the clutch fingers 25 during clutch operation. The outer surface 36 of the rotatable release bearing race 23 constitutes a guide surface for co-operation with the guide surface 34, 35.

In order to ensure that the guide element 29 with its guide surface 34 and 35 is in accurate axial alignment with the axis of rotation of the clutch as a whole, the guide element 29 should be aligned accurately with the axis of rotation of the clutch as a whole prior to welding rather than being aligned either with the diaphragm spring or the location element 28. This ensures that small inaccuracies in the position of the diaphragm spring and the location element 28 are not carried over to the guide surface.

The clutch release assembly is operated in the normal way by an axially movable release fork 26.

WHAT WE CLAIM IS: 1. A clutch release assembly for a diaphragm spring clutch, the assembly comprising a diaphragm spring having radial fingers co-axially supporting and locating a guide ring, a non-rotatable axially movable release member and a rolling element bearing having a rotary race arranged to apply an axial release load to the diaphragm spring and a non-rotatable race radially adjustably mounted on the release member, to allow axial alignment betwen the bearing and the diaphragm spring, the rotatable race and guide ring having mutually co-operating guide surfaces, one of which has a tapered lead-in whereby the release bearing is axially aligned with the diaphragm spring as the rotary race is brought into engagement with the guide ring by operation of the release member, the guide ring comprising two annular parts, respectively a location element fixed between adjacent fingers of the diaphragm spring and a guide element fixed to the location element and axially aligned with the diaphragm spring.

2. An assembly according to Claim 1, in which the two parts of the guide ring are ultra-sonically welded together.

3. A clutch release assembly substantially as described with reference to, and as shown by, the accompanying dawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. race 23 which is guided with respect to the race 15 by a series of balls 24. The race 23 has an annular forward extension which terminates in a curved clutch engagement surface 37 which is intended to bear against the inner part of the diaphragm spring fingers of a diaphragm spring clutch. One diaphragm spring finger 25 is shown diagrammatically in the drawing in engagement with surface 37. The diaphragm spring supports a guide ring 27 which is constituted by a location element 28 and a guide element 29. The location element 28 is in the form of an annular ring with a cruved annular face 31 for engagement with the diaphragm spring fingers and with a series of projections 32 which extend through the gaps between adjacent fingers and hence locate the location element positively against any radial movement with respect to the diaphragm spring. The guide element 29 is secured by means such as ultrasonic welding to the ends of the projections 32 on the opposite side of the diaphragm spring from the ring of the location element 28. The guide element also incorporates a curved face 33 which engages the diaphragm spring fingers and together with the curved face 31 permits relative angular movement between the fingers 25 and the guide ring 27. The guide element 29 has an inner annular guide surface which has a generally axial forward portion 34 and a tapered lead-in 35. It is important for the guide surface 34 and 35 to be accurately in axial alignment with the axis of rotation of the clutch as a whole. When the clutch and the release bearing are assembled together, which normally occurs when a gearbox is secured to an engine and clutch combination, the tapered lead-in 35 co-operates with the curved clutch engagement surface 37 of the release bearing so that the release bearing is moved radially if necessary to bring it into accurate axial alignment with the guide surface 34 and 35 and the axis of clutch rotation. The axial forward portion 34 of the guide surface ensures that the coaxial relationship is retained during small axial movement between the guide ring and the release bearing. Such axial movement may in part be a small clearance when the clutch is released but also includes movement to accommodate inclination of the clutch fingers 25 during clutch operation. The outer surface 36 of the rotatable release bearing race 23 constitutes a guide surface for co-operation with the guide surface 34, 35. In order to ensure that the guide element 29 with its guide surface 34 and 35 is in accurate axial alignment with the axis of rotation of the clutch as a whole, the guide element 29 should be aligned accurately with the axis of rotation of the clutch as a whole prior to welding rather than being aligned either with the diaphragm spring or the location element 28. This ensures that small inaccuracies in the position of the diaphragm spring and the location element 28 are not carried over to the guide surface. The clutch release assembly is operated in the normal way by an axially movable release fork 26. WHAT WE CLAIM IS:

1. A clutch release assembly for a diaphragm spring clutch, the assembly comprising a diaphragm spring having radial fingers co-axially supporting and locating a guide ring, a non-rotatable axially movable release member and a rolling element bearing having a rotary race arranged to apply an axial release load to the diaphragm spring and a non-rotatable race radially adjustably mounted on the release member, to allow axial alignment betwen the bearing and the diaphragm spring, the rotatable race and guide ring having mutually co-operating guide surfaces, one of which has a tapered lead-in whereby the release bearing is axially aligned with the diaphragm spring as the rotary race is brought into engagement with the guide ring by operation of the release member, the guide ring comprising two annular parts, respectively a location element fixed between adjacent fingers of the diaphragm spring and a guide element fixed to the location element and axially aligned with the diaphragm spring.

2. An assembly according to Claim 1, in which the two parts of the guide ring are ultra-sonically welded together.

3. A clutch release assembly substantially as described with reference to, and as shown by, the accompanying dawing.