GB2373032A

GB2373032A - Multiplate clutch for concentric shafts

Info

Publication number: GB2373032A
Application number: GB0105359A
Authority: GB
Inventors: Shaun Ewan Mepham
Original assignee: Prodrive 2000 Ltd
Current assignee: Prodrive 2000 Ltd
Priority date: 2001-03-05
Filing date: 2001-03-05
Publication date: 2002-09-11
Also published as: GB0105359D0

Abstract

An inner shaft 12 and concentric outer shaft 14 can be connected by a multiplate clutch assembly made up of a number of clutch plates 20,22 fixed to the shafts 12,14 by splines 16,18 between end plates 24,26. One end plate 24 receives a force F to engage the clutch and the second end plate 26 abuts a lip 28 to keep the clutch in place. A spring 30 may be provided to cushion the shock of the force F.

Description

Differential Clutch Cushion Spring

The present invention relates to a differential clutch and in particular an automotive differential clutch.

According to the present invention there is provided a differential clutch assembly adapted to selectively couple and decouple concentric inner and outer shafts, the clutch assembly comprising at least one clutch plate fixed for rotation with said inner shaft, at least one clutch plate fixed for rotation with said outer shaft and opposed clutch endplates adapted to clamp said clutch plates together upon the application of a clutch engagement force to one of said endplates, wherein the other of said clutch endplates includes stop means adapted to limit movement of the clutch assembly longitudinally relative to said shafts in the direction of application of said force, the stop means further including a spring.

In a preferred embodiment the stop means further include a lip of one of the shafts, the spring being interposed between said lip and clutch endplate. Preferably said lip is provided on the inner shaft. Preferably the spring is preloaded so as to resist said clutch engagement force up until it exceeds said pre-load. The spring may have either a linear or non-linear spring rate depending upon desired operating characteristics. In a preferred embodiment the clutch assembly includes multiple clutch plates fixed for rotation with said shafts.

An embodiment of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a cross-sectional side view of a differential clutch in accordance with the present invention; and Figure 2 shows a graph of applied force against displacement for the clutch of figure 1.

Referring firstly to figure 1 there is shown a clutch assembly generally designated 10.

The assembly 10 is provided between an inner shaft 12 and a concentric annular outer shaft 14 provided with respective splined portions 16,18. The clutch assembly 10 is

1 n adapted to selectively couple and decouple the shafts 12, 14. The clutch assembly 10 comprises a plurality of clutch plates 20,22 alternatively engaged on the splines 16,18 of the respective shafts 12,14, and provided between end plates 24,26. A first end plate 24 is adapted to receive a force input F from appropriate actuator means (not shown) to engage the clutch assembly 10, in use, while the second end plate 26 is secured relative to the inner shaft 12 so as to resist movement of the clutch assembly 10 in the direction of the force application. The second end plate 26 is located relative to the inner shaft 12 by the provision of a circumferential lip 28 on the inner shaft 12 and a spring 30 provided between the lip 28 and the second end plate 26. The spring 30 is preloaded so as to initially bias the clutch assembly 10 away from the lip 28.

Operation of the assembly will now be described with reference to figure 2. As force is applied to the first endplate 24 to engage the clutch, movement of the clutch assembly 10 is resisted by the spring 30. Initial displacement d of the clutch assembly is limited to the take up of any spacing between the clutch plates 20,22 as they are moved into engagement with one another as a result of being compressed between the endplates 24, 26. As the applied force F increases the resistive force of the spring 30 is overcome with the result that spring 30 is compressed and the clutch assembly 10 displaced longitudinally in the direction of application of force F. Once the spring 30 is fully compressed the clutch assembly 10 is limited against further longitudinal movement by the lip 28. Increased application of force F serves to fully compress the clutch plates 20,22 between the end plates 24,26 until the clutch is fully engaged and the shafts 12,14 coupled for rotation. Elimination of the force F results in clutch assembly 10 being disengaged and extension of the spring 30 to its initial unloaded state with consequent movement of the clutch assembly 10 longitudinally in the opposite direction to that of force application.

The present invention introduces a degree of compliance into a multi-plate differential clutch assembly thereby softening the usual harsh transition between the engaged and disengaged states. In the embodiment described above, compression of the spring is linear however it will be understood that the pre-load and compression characteristics may be varied so as to achieve desired compliance characteristics.

Claims

Claims 1. A differential clutch assembly arranged to selectively couple and uncouple concentric inner and outer shafts, the assembly comprising at least one clutch plate fixed for rotation with the inner shaft, at least one clutch plate fixed for rotation with the outer shaft, and opposed clutch end plates adapted to clamp the clutch plates together upon the application of a clutch engagement force to one of the end plates, wherein the other of the clutch end plates includes stop means adapted to limit movement of the clutch assembly in the longitudinal direction relative to said shafts in the direction of application of said force, the stop means including a spring.
2. A clutch assembly according to claim 1 wherein the stop means includes a lip on one of the shafts, the spring being interposed between the lip and the clutch end plate.
3. A clutch assembly according to claim 2 wherein said lip is provided on the inner shaft.
4. A clutch assembly according to any one of the preceding claims wherein the spring is preloaded so as to resist said clutch engagement force until it exceeds said preloaded value.
5. A clutch assembly according to any one of the preceding claims wherein the spring has a linear or non-linear spring rate depending upon the desired operating characteristics.
6. A clutch assembly according to any one of the preceding claims comprising multiply clutch plates fixed for rotation with the associated shafts.