| 摘要 |
PURPOSE:To secure and enhance both the turning-round property of a vehicle in a low vehicle speed area and the stability of the vehicle in a high vehicle speed area at high degrees and to allow a driver to choose a gear ratio so as to enhance the serviceability of the vehicle by properly changing the magnitude of gear ratio together with the vehicle speed according to the steering speed of a steering wheel. CONSTITUTION:A gear ratio selection means 37 has at least two high and low gear ratio characteristics defined as functional expressions in which vehicle speed is taken as a parameter, and selects the low gear ratio characteristic at below first predetermined vehicle speed, the high gear ratio characteristic at more than second predetermined vehicle speed which is higher than the first speed, and a gear ratio characteristic corresponding to the steering speed of a steering wheel detected by a steering speed detection means 35 or to the selection signal of a manual switch in a speed area between the first and second predetermined vehicle speeds. The control valves 17, 23 of a wheel steering means 24 are controlled on the basis of a selected gear ratio characteristic. |
