| 摘要 |
PURPOSE:To enable optimum rear wheel steering in each of released and locked conditions of a center differential gear by controlling rear wheel steering in said conditions in such a way as to meet the turning characteristics therein. CONSTITUTION:A front wheel steering angle sensor 1, a speed sensor 2 and a rear wheel steering angle sensor 3 are provided, and output signals from said sensors are inputted to a control unit 4. On the basis of the preliminarily determined characteristics of front and rear wheel steering angle ratios, the control unit 4 determines an applicable rear wheel steering angle and an electric motor 6 as an actuator for rear wheel steering is driven and controlled via a drive circuit 5. In this case, in a 4-wheel drive vehicle equipped with a center differential gear having a differential limiting device, two types of front and rear wheel steering angle ratio characteristics matching each of turning characteristics in the released aud locked conditions of the differential gear are set up as the predetermined characteristics, and the characteristics so set up are used selectively depending upon the output signals of a center differential gear locking sensor 13. |
