SHIFTING CONTROL FOR TWO-WHEEL DRIVE FROM/INTO FOUR-WHEEL DRIVE

摘要

PURPOSE:To prevent a main shaft, a differential gear, an acceleration shaft or the like from any damage, and the decrease of braking force in 2WD-4WD shifting control of a transfer device by shifting in into 4WD forcibly at the time of a low speed position in 4WD, and shifting 4WD into 2WD forcibly at the time of ABS operation. CONSTITUTION:Respective signals of 2WD-4WD shifting, low-high position, main shaft 5 speed, steering angle and ABS operation are inputted into a controller 25. It is judged whether a 4WD switch is on. If not on, it is judged whether the position is low, and when at a high position, 2WD shifting control is made. When at a low position, it is judged whether an ABS signal is on, and at the time of ABS operation, 2WD shifting control is carried out to prevent torque interference even at a low position. In the case of no ABS operation, it is judged whether the steering angle theta is above a prescribed value A, and then in the case of thetaA, 4WD shifting control is carried out. In the case of theta=A, it is judged whether the number of rear revolutions N is a prescribed value B or less. In the case of N=B, 2WD shifting control is carried out, and in the case of NB, 4WD shifting control is carried out.