GB2153479A

GB2153479A - Clutch control device

Info

Publication number: GB2153479A
Application number: GB08501274A
Authority: GB
Inventors: Yvon Sevennec
Original assignee: Valeo SE
Current assignee: Valeo SE
Priority date: 1984-01-25
Filing date: 1985-01-18
Publication date: 1985-08-21
Also published as: ES8606927A1; DE3502341A1; FR2558551B1; ES539811A0; IT8512409A0; FR2558551A1; GB8501274D0; GB2153479B; IT1186809B

Abstract

The clutch control device comprises an actuating fork (21) mounted pivotally about an axis (A1), and a motor shaft (25) mounted rotatably about en axis (A2). Levers (30 and 31) pivot the fork (21) in response to a rotary movement of the motor shaft (25). The lever (30) is mounted rotatably about the axis (A1) and is non-rotatably fixed with respect to the fork (21). The lever (31) is connected to the motor shaft (25) by meshing means (29, 33) and is mounted rotatably about an axis (A3). Abutment means (40, 41) are interposed between the levers (30 and 31) for entrainment of the lever (30) by the lever (31). The three axes (A1, A2, A3) are parallel to one another. The motor shaft (25) is drivable by an electric motor (28) via a worm (27) and toothed wheel (26). The abutment means comprise a slot (41) in either lever (30 or 31) engaged by the rounded head of a projection (40) carried by the other lever. <IMAGE>

Description

SPECIFICATION Clutch control device This invention relates to a clutch control device including an actuating fork mounted pivotally about a first axis, a motor shaft mounted rotatably about a second axis which is parallel to the first axis, and lever means interposed between the fork and the motor shaft for pivoting the fork in response to the rotary movement of the motor shaft In general, such lever means conventionally comprises single lever which is fixed with respect to the fork and which pivots about the first axis, the lever carrying a toothed sector which engages with a pinion which is non-rotatably fixed with respect to the motor shaft.This arrangement is generally satisfactory and is suitable under good conditions for use in a motorised clutch control system, that is to say, a system in which a motor, generally an electric motor, drives the motor shaft of the clutch control system.

However, such an arrangement suffers from various disadvantages. In particular, however precise and accurate assembly of the arrangement is, it is liable to become locked up and to jamming and gives rise to difficulties of a practical nature in regard to installing the clutch control system within the adjoining components, in particular in the case of a motor vehicle clutch, on the casing of the gearbox.

Additionally the known arrangement having a single lever does not make it possible easily to select, as desired, the most favourable transmission ratio between the motor shaft and the axis of the fork.

There is thus a need for a generally improved clutch control device provides greater convenience of installation and reduced risk of jamming or locking up while making it possible to select, at a desired value, a predetermined transmission ratio between the motor shaft and the axis or spindle of the fork.

According to the present invention there is provided a clutch control device including an actuating fork mounted pivotally about a first axis, a motor shaft mounted rotatably about a second axis which is parallel to the first, and lever means interposed between the fork and the motor shaft, wherein the lever means includes a first lever which is mounted for rotation about the first axis and which is nonrotatably fixed with respect to the fork, and a second lever which is connected to the motor shaft by meshing means and which is mounted for rotation about a third axis extending in the same direction as the first and second axes, abutment means being interposed between the two levers for entrainment of the first lever by the second lever.

On this device entrainment of one lever by the other imparts to the assembly a degree of freedom as preferably the abutment means are constructed to accommodate possible inaccuracies and lack of precision in regard to parallelism and/or inter-axis spacing between the first two axes. This eliminates danger of locking up or jaming in the control system.

The third axis may be coaxial with the first axis, if desired, in which case the transmission ratio is the same as that which would be obtained if the lever means comprises a single lever. However, the provision of such a third axis makes it possible to introduce a predetermined transmission ratio, as desired. It is only necessary suitably to select the location of the third axis in order to give a predetermined transmission ratio as indicated above. For example, the third axis may advantageously be located between the first two axes while the abutment means are disposed between the second and third axes. Under those conditions, the predetermined transmission ratio is a step-down ratio, which is generally desirable in a clutch control system of the type considered here.

In accordance with another preferred feature, the first axis is connected to a first fixed casing, for example in the case of a motor vehicle, the casing of the gearbox, while the second and third axes are connected to a second fixed casing which incorporates the two levers and which is constructed to be mounted as a unit on the first fixed casing.

This provides a monolithic construction in the form of the second fixed casing which merely has to be mounted on the first fixed casing. Even when such assembly suffers from inaccuracies, the abutment means connecting the two levers make it possible to accommodate such inaccuracies and to achieve satisfactory operation of the assembly under all circumstances. The first fixed casing also advantageously incorporates an electric motor for driving the motor shaft of the control system.

Advantageous, a concertina-type sealing member is mounted between the two casings to prevent dust or foreign particles from being introduced into the second fixed casing. The latter therefore constitutes a sealed unit and forms an assembly which is ready to be mounted immediately, without any difficulty, on the first fixed casing, that is to say, the gearbox casing in th case of a motor vehicle.

The abutment means advantageously comprise a projection or lug which is fixed to one of the levers and which has a head in the form of a ball joint engaged in an elongate housing or recess in the other lever. In this way, with a particularly simple and robust construction, the assembly provides for transmission of the clutch operating movement under excellent conditions which are not affected by inaccuracies in assembly and which moreover, if desired, make it possible to use a predetermined transmission ratio.

The projection or lug may be fixed to the second lever and the housing or recess is provided in the first lever, but it is also possible to envisage fixing the projection to the first lever while the housing is provided in the second lever. In the latter case, it is possible to use a standard assembly which incorporates the second fixed casing, the motor, the motor shaft, the second lever and its elongate housing or recess, and, when there are different models of vehicle, it is only necessary to modify merely the first lever in order to safisty the conditions relating to each model.

Embodiments of the invention are described hereinafter by way of example with reference to the accompanying drawings in which: Figure 1 shows a clutch control device according to the invention in longitudinal section taken along line I-I in Figure 3, the clutch being shown in the engaged position, Figure 2 is a similar view to that shown in Figure 1, but showing the clutch in the disengaged position, Figure 3 is a view of the clutch control device in cross-section taken along line Ill-Ill in Figure 1, and Figure 4 shows an alternative form in which a detail in Figure 3 is modified.

Reference will first be made to Figures 1 to 3 which concern, by way of non-limiting example, the application of the invention to a clutch for a motor vehicle.

The clutch (Figures 1 to 3) comprises a cover 10 which is adapted to be fixed to the flywheel 11 of the engine of the motor vehicle. The flywheel 11 constitutes a reaction plate. The clutch also comprises a friction disc 12 which is coupled to the primary shaft 13 of the gearbox 14 of the vehicle, the casing thereof being shown at 15 (see Figure 3).

The disc 12 is arranged to be gripped between the plate 11 and a pressure plate 16 under the resilient gripping force of a diaphragm spring 17. The diaphragm spring 17 bears against the cover 10 at 18 and in its central region has fingers 19 which are arranged to be pushed towards the left in Figure 1 by a clutch release bearing 20 when the clutch is to be moved from its engaged condition as shown in Figure 1 wherein the clutch release bearing 20 has no effect on the diaphragm spring 17 to a clutch release position as shown in Figure 2 in which the clutch release bearing 20, by thrusting against the diaphragm spring 17, terminates the gripping force applied to the pressure plate 16, thereby freeing the friction disc 12.

The clutch control arrangement comprises an actuating fork 21 (Figure 1 to 3) which is mounted pivotally about a first axis Al. More particularly, the fork 21 is fixed with respect to a shaft 22 which is mounted rotatably in bearings 23 carried by the casing 15 of the gearbox 14.

The shaft 22 has a splined end portion 24.

A motor shaft 25 is mounted rotatably about a second axis A2 which is parallel to the axis Al. More particularly, the motor shaft 25 carries a pinion 26 which is entrained by an endless worm 27 which is itself driven in rotation by an electric motor 28. The motor shaft 25 also carries a pinion 29.

Lever means 30 and 31 are interposed between the fork 21 and the motor shaft 25 and cause the fork 21 to pivot in response to a rotary movement of the motor shaft 25.

The lever means 30 and 31 comprise two levers: a first lever 30 which is mounted rotatably aboutthe first axis Al and which for the purpose comprises a splined hub portion 32 which is engaged on the spline end portion 24 of the shaft 22, the first lever 30 thus being non-rotatably fixed with respect to the fork 21; and a second lever 31 which is connected to the motor shaft 25 by meshing means comprising the pinion 29 and a toothed sector 33. The second lever 31 is mounted rotatably about a third axis A3, in the same direction as the axes Al and A2. More particularly, the lever 31 is mounted by means of a bearing 34 on a trunion 35 which is carried by a casing 36 which is adapted to be fixed to the casing 15 of the gearbox 14.

The casing 36 incorporates the two levers 30 and 31 and carries the motor 28. It thus forms a monolithic assembly which is adapted to be fixed as desired to the casing 15, the splined hub portion 32 being fitted on to the splined end portion 24 of the shaft 22, and a resilient concertina-type sealing member or boot 37 being mounted between the two casings 15 and 36 to prevent dust or other particles from passing into the sealed assembly formed by the casing 36 and containing the levers 30 and 31.

Abutment means 40 and 41 are interposed between the levers 30 and 31, within the casing 36, for the lever 30 to be entrained by the lever 31.

In the embodiment illustrated in Figures 1 to 3, the abutment means 40 and 41 comprise a lug or projection 40 which is fixed to the lever 31 and which has a head 43 in the form of a ball joint member engaged in an elongate housing or slot 41 in the lever 30. It will be appreciated that the contact connection at 40, 41 is a sliding contact and has one degree of freedom more than a connection formed by a simple pivot.

The abutment means 40 and 41 are thus adapted to accommodate any inaccuracies in regard to parallelism and inter-axis spacing between the axes Al and A2 which may result from tolerances in the construction or fitting of the casing 36 to the casing 15.

It will be noted that the third axis A3 is disposed at a spacing from the first axis Al,which makes it possible to introduce a transmission ratio which is of a predetermined value by means of the two levers 30 and 31. More particularly, the third axis A3 is disposed between the axes Al and A2 while the abutment means 40 and 41 are disposed between the second axis A2 and the third axis A3 so that the predetermined transmission ratio is a step-down ratio.

In the course of rotary movement of the motor shaft 25 under the control of the motor 28, the ball joint member 40, while pushing against the side of the housing or slot 41, is permitted to move therewithin, which makes it possible to transmit the movement to the lever 30 which actuates the fork 21 to move the clutch from the engaged condition as illustrated in Figure 1 to the disengaged condition as shown in Figure 2, or vice-versa.

It will be appreciated that the casing 36 incorporating the motor 28 and the levers 30 and 31 may be immediately fixed to the casing 15 of the gearbox 14, the splined hub portion 32 being simply fitted on to the splined end portion 24 of the shaft 22.

The arrangement provides an irreproachable mode of operation by virtue of the degree of freedom introduced by the ball joint member 40 in the housing 41, at the same time as a suitable step-down ratio.

In the alternative form shown in Figure 4, the arrangement of the components is similar to that desribed above with reference to Figures 1 to 3 but, instead of the ball joint member 40 being carried by the lever 31, it is carried by the lever 30, and in this case the elongate housing or slot 41 is provided in the lever 31.

That arrangement makes it possible to standardise manufacture with the same motor 28, the same shaft 25 and the same lever 31 and, depending on the vehicle models, it is only necessary to choose a lever 30 which is adapted to each model.

It will be appreciated that the invention is not limited to the embodiments described and illustrated but covers any alternative forms in regard to the various components thereof and in regard to its applications, within the scope of the appended

Claims

claims. CLAIMS

1. Aclutch control device including an actuating fork mounted pivotally about a first axis, a motor shaft mounted rotatably about a second axis which is parallel to the first, and lever means interposed between the fork and the motor shaft for pivoting the fork in response to a rotary movement of the motor shaft, wherein the lever means includes a first lever which is mounted for rotation about the first axis and which is non-rotatably fixed with respect to the fork, and a second lever which is connected to the motor shaft by meshing means and which is mounted for rotation about a third axis extending in the same direction as the first and second axes, abutment means being interposed between the two levers for entrainment of the first lever by the second lever.

2. A clutch control device according to claim 1, wherein the abutment means are constructed to accommodate inaccuracies in parallelism and interaxis spacing between the first two axes.

3. A clutch control device according to claim 1 or claim 2, wherein the third axis is spaced from the first axis to introduce a predetermined transmission ratio.

4. A clutch control device according to claim 3, wherein the third axis is disposed between the first two axes while the abutment means are disposed between the second axis and the third axis such that the predetermined transmission ratio is a step-down ratio.

5. A clutch control device according to any one of claims 1 to 4, wherein the abutment means include a projection which is fixed to one of the levers and which has a head in the form of a ball joint member engaging in an elongate housing of the other lever.

6. A clutch control device according to claim 5, wherein the projection is fixed to the second lever while the elongate housing is provided in the first lever.

7. A clutch control device according to claim 5, wherein the projection is fixed to the first lever while the elongate housing is provided in the second lever.

8. A clutch control device according to any one of claims 1 to 7, wherein the first axis is connected to a first fixed casing while the second axis and the third axis are connected to a second fixing casing which incorporate the two levers and which is mountable as a unit on the first fixed casing.

9. A clutch control device substantially as hereinbefore described with reference to Figures 1 to 3 or Figure 4 of the accompanying drawings.