Patent ID: 8256559
Filing Date: 2012-09-04
Classification: B60K,F16D,F16H

Abstract:
1. A driving force transmission device for a four-wheel-drive vehicle, the driving force transmission device comprising: a switch mechanism for switching between a four-wheel-drive mode in which a fastening power of a multi-disc clutch mechanism is changed continually and a driving force distribution to front and rear wheels is automatically controlled depending on running conditions, and a two-wheel-drive mode in which the multi-disc clutch mechanism is released and the driving force distribution is transmitted only to the rear wheels; and a disconnection/connection mechanism for disconnecting and connecting a front wheel differential to which the driving force distributed by the multi-disc clutch mechanism is input and one or both of left and right front wheel drive shafts, wherein a dragging torque of the multi-disc clutch mechanism is made smaller than a rotation resistance of a front wheel driving force transmission section from the multi-disc clutch mechanism to the disconnection/connection mechanism in the two-wheel-drive mode, and the front wheel differential and the one or both of the left and right front wheel drive shafts are disconnected by the disconnection/connection mechanism and thereby a rotation of the front wheel driving force transmission section is stopped.