DRIVING FORCE DISTRIBUTION DEVICE

PROBLEM TO BE SOLVED: To provide a driving force distribution device capable of inhibiting overheating in the driving force transmission system of auxiliary drive wheels in performing the traction drive of a four-wheel drive vehicle equipped with main drive wheels to which torque is always transmitted from a drive source and the auxiliary drive wheels in which torque transmission is interrupted according to vehicle travelling conditions. SOLUTION: An ECU determines the traction of a vehicle based on the driving force and the acceleration (STEP 101). When the vehicle is in traction travelling (STEP 102: YES), the ECU determines the skid condition of the vehicle based on speed differences between wheels (STEP 103). When the vehicle is not in a skid condition (STEP 104: YES), the ECU determines whether a counter (n) is beyond a predetermined counter (n-th) or not. When the counter (n) is beyond the predetermined counter (n-th) (STEP 105: YES), the driving force distribution device shifts toward traction control for reducing the transmission torque of torque coupling (STEP 108). COPYRIGHT: (C)2008,JPO&INPIT