WO2015158916A1

WO2015158916A1 - A coupling

Info

Publication number: WO2015158916A1
Application number: PCT/EP2015/058442
Authority: WO
Inventors: Lars Severinsson
Original assignee: Borgwarner Torqtransfer Systems Ab
Priority date: 2014-04-17
Filing date: 2015-04-17
Publication date: 2015-10-22

Abstract

A coupling for connecting a driven axle with a non-driven axle is provided. The coupling comprises a disc coupling and a piston for actuating the disc coupling, wherein the coupling further comprising a lock mechanism being configured to permanently apply a pressure to the piston of the disc coupling when actuated, wherein lock mechanism actuation is provided by applying a pressure impact to the lock mechanism.

Description

A COUPLING

Technical Field

The present invention relates to a coupling having a lock mechanism. More particularly the present invention relates to a coupling for a vehicle combining a disc coupling and a lock mechanism.

Background

In vehicles it may be beneficial to allow a permanent connection between two shafts. For example in transfer case applications it is necessary to lock the font and rear axles to each other during off road driving or other demanding situations in which it is difficult to apply slip control or other algorithms for controlling disc coupling torque. The same need is also present in other torque transfer applications, such as differential brakes.

A pump used for hydraulic activation of disc couplings is described in

WO201 1043722. However the described solution does not allow for constant application of maximum torque due to overheat of the DC motor. Further, even if cooling of the motor is provided the power consumption of such solution would be far too excessive.

Summary

An object of the present invention is to solve the above mentioned drawbacks. One idea is to combining a disc coupling and a locking mechanism which is locked by a pressure impact. Unlocking the locking mechanism is provided by actuating a hydraulic piston of the disc coupling.

According to aspects of the present invention, a coupling is provided in accordance with the features set forth in the independent claims. Preferred embodiments are defined by the appended dependent claims. Brief Description of Drawings

Embodiments of the invention will be described in the following; reference being made it the appended drawings which illustrate non-limiting examples of how the inventive concept can be reduced into practice.

Fig. 1 shows a coupling according to an embodiment;

Fig. 2 is a cross-sectional view of the coupling shown in Fig. 1 in a locked position; Fig. 3 is a cross-sectional view of the coupling shown in Fig. 1 in an unlocked position;

Fig. 4 shows a coupling according to an embodiment;

Fig. 5 is a cross-sectional view of the coupling shown in Fig. 4 in a locked position;

Fig. 6 is a cross-sectional view of the coupling shown in Fig. 4 in an unlocked position; and

Fig. 7 is a cross-sectional view of a coupling according to a further

embodiment.

Detailed Description

Fig. 1 shows a coupling according to a first embodiment. The coupling has a disc coupling which is actuated by a hydraulically actuated piston (referred to as AWD piston in Fig. 1). A lock mechanism is also provided comprising a disc spring, a lock piston, a release piston, and a locking ring.

The coupling is enclosed in a housing, or sleeve having two hydraulic inlets (input 1 and input 2 as seen in Figs. 2-3).

Fig. 3 shows the coupling when operated in normal AWD mode, i.e. connecting the front and rear axles by applying a specific torque to the AWD piston via input 2. Should a permanent connection be required hydraulic pressure is provided at input 1 whereby a pressure impact will force the release piston and lock piston to the right as is shown in Fig. 2. At the same time the disc spring is compressed, thus applying a constant force on the AWD piston, and the locking ring is snapped into the position of Fig. 2 in order to keep the disc spring compressed also when the hydraulic pressure is released.

When the permanent connection is to be released, thus returning to normal AWD mode, pressure is provided at input 2 whereby the release piston is pushed towards the left as is shown in Fig. 3. A cone, i.e. the upper (or radially outer) surface of the release piston will move the locking ring out from the snap groove and the lock piston will thus be allowed to release the pressure on the disc spring, as well as on the AWD piston.

Figs. 4-6 show another embodiment of a coupling. The coupling has a disc coupling which is actuated by a hydraulically actuated piston (referred to as AWD piston in Fig. 4). A lock mechanism is also provided comprising a disc spring, a lock piston, a release piston, a locking ring, and a release cone.

The coupling is enclosed in a housing, or sleeve having two hydraulic inlets (input 1 and input 2 as seen in Figs. 5-6). Fig. 6 shows the coupling when operated in normal AWD mode, i.e. connecting the front and rear axles by applying a specific torque to the AWD piston via input 2. Should a permanent connection be required hydraulic pressure is provided at input 1 whereby a pressure impact will force the release piston, lock piston, and release cone to the right as is shown in Fig. 5. At the same time the disc spring is compressed, thus applying a constant force on the AWD piston, and the locking ring is snapped into the position of Fig. 2 in order to keep the disc spring compressed also when the hydraulic pressure is released.

When the permanent connection is to be released, thus returning to normal AWD mode, pressure is provided at input 2 whereby the release piston is pushed towards the left as is shown in Fig. 3. The release cone will consequently move the locking ring out from the snap groove and the lock piston will thus be allowed to release the pressure on the disc spring, as well as on the AWD piston.

A yet further embodiment of a coupling is shown in Fig. 7.

Claims

1. A coupling for connecting a driven axle with a non-driven axle, comprising a disc coupling and a piston for actuating the disc coupling,

characterized in that the coupling further comprising a lock mechanism being configured to permanently apply a pressure to the piston of the disc coupling when actuated, wherein lock mechanism actuation is provided by applying a pressure impact to the lock mechanism.

2. The coupling according to claim 1 , further comprising a first inlet for providing hydraulic fluid for disc coupling actuation, and a second inlet for providing hydraulic fluid for lock mechanism actuation.

3. The coupling according to claim 2, wherein the lock mechanism comprises a moveable lock piston for compressing a disc spring against the piston of the disc coupling in a locking position, a locking ring for snap locking the lock piston in the locking position, and a release piston having a release cone being moveable in order to release the locking ring.

4. The coupling according to claim 2 and 3, wherein the first inlet is in connection with the lock piston, and the second inlet is in connection with the piston of the disc coupling as well as with the release piston.

5. The coupling according to claim 3 or 4, wherein the release cone is formed integrally with the release piston.

6. The coupling according to any one of the preceding claims, wherein the lock mechanism is released by applying a pressure impact to the piston of the disc coupling.

7. A transfer case, comprising a coupling according to any one of the preceding claims.

8. A differential brake, comprising a coupling according to any one of claims

1-6.

9. A vehicle, comprising a transfer case according to claim 7 and/or a differential brake according to claim 8.