FRONT AND REAR WHEEL TRANSMISSION IN FOUR-WHEEL DRIVE VEHICLE

摘要

PROBLEM TO BE SOLVED: To provide a front and rear wheel transmission in a four wheel drive vehicle which can effectively employ the change gear ratio range by determining a target change gear ratio of the variable speed for the rear wheels obtained in response to the width of the steering angle on the basis of the target change gear ratio of the variable speed for the front wheels. SOLUTION: So as to avoid tight corner brake phenomena caused by steering, a controller 30 is adapted to additionally correct a target tilted and rotating angleϕcr for rear wheels in variable speed for the rear wheels which is calculated according to the driving situation of a vehicle on the basis of the steering angleζdetected by a steering angle detection sensor 18, so that the target tilted and rotating angleϕcf for the front wheels is calculated and set in the variable speed for the front wheels. When the vehicle is driven at a slow speed in a wide steering angle, an additional margin for shift toward speed reduction side is not required for the target tilted and rotating angleϕcr for the rear wheels which has been shifted to the speed reduction side, so that the range of the change gear ratio can be effectively utilized.