| 摘要 |
PURPOSE:To obtain a device high in reliability and unconstrained in layout by constructing the device in such a way as to change a rear wheel solenoid control valve over to the negative-phase mode by fluid pressure when front and rear wheels are steered reversely by turning a steering wheel largely. CONSTITUTION:When a steering wheel 11 is turned largely, a metering cylinder MC is put in action to actuate a pilot cylinder PC feeding it with delivered fluid pressure so as to change a rear wheel solenoid control valve RV over to the negative-phase mode. If the turning angle of the steering wheel 11 is small, the rear wheel solenoid control valve RV is not changed over as the pilot cylinder PC acts in the range of a deadband. When the speed exceeds the fixed speed, a controller C excites solenoids 41, 42 so as to change the rear wheel solenoid control valve RV over to the in-phase mode. In addition, in turning the steering wheel largely, the steering directions of front and rear wheels 14, 48 are reversed in the case of low speed running, and in small turning, the steering direction of the front and rear wheels 14, 48 are made the same in the case of high speed running. |
