| 摘要 |
PURPOSE:To prevent an understeer phenomenon from increasing by steering a rear wheel in a reverse phase with a decrease of turning radius of a vehicle when a rear wheel rotary speed is faster than a front wheel rotary speed and when lateral acceleration of the vehicle is larger than a predetermined value. CONSTITUTION:A rear wheel steering control device 30, which performs a rear wheel steering control being based on input information of, a difference N or the like between front and rear wheel rotary speeds when a vehicle is in turning by its handle operation, is provided. This device 30 has a rear wheel steering control unit 36 inputting detecting signals from a steering angle sensor 31, right front wheel speed sensor 32, left front wheel speed sensor 33, right rear wheel speed sensor 34 and a left rear wheel speed sensor 35, rear wheel steering control valve 38 controlling pressure oil from an external hydraulic pressure source 37 to a predetermined control pressure being based on an instruction from the rear wheel steering control unit 36 and a rear wheel power steering 39 steering a rear wheel by the control pressure from the rear wheel steering control valve 38. The control unit 36, when the vehicle is in turning approaching the limit, outputs a signal steering the rear wheel so as to be in a reverse phase to a front wheel. |
