Patent ID: 6131686
Filing Date: 2000-10-17
Classification: B60K,B60W

Abstract:
In a transmission for a motor vehicle having front wheels and rear wheels operably interconnected by a selectable four-wheel drive including a coupling for selectively applying torque to the front wheels of the vehicle to switch between a two-wheel drive mode of operation and a four-wheel drive mode of operation, said coupulng including a drive member rotatable with the rear wheels and a driven member rotatable with the front wheels, the drive and driven members being movable axially relative to one another, the improvement comprising:teeth on the drive and driven members which mesh with one another in a first relative axial position of the drive and driven members to transmit torque with a limited degree of lost motion from the drive member to the driven member and which are disengaged from one another in a second relative axial position of the drive and driven members to disconnect the drive to the front wheels,first determining means for determining slip between the rear wheels and the road surface, said first determining means including sensing teeth respectively provided on the drive and driven members, the number of sensing teeth respectively being twice the number of the respective teeth on the drive and driven members for transmitting torque, andactuating means for axially moving the drive and driven members between the first and second relative positions in dependence upon the determined presence or absence of slipping of the rear wheels.