| 摘要 |
PURPOSE:To improve steerability, by automatically reversing the polarity of a desired steering value when a car is steered with a mode to steer both front and rear wheels in the same direction in order to make a car body into horizontal movements and backward, in case of an automatic traveling farm working vehicle being steerable of both front and rear wheels. CONSTITUTION:In case of such one that rolls and steers both front and rear wheels 2 and 3 by each of hydraulic cylinder 7 and 8 and controls each of solenoid valve 9 and 10 actuating and controlling each of these hydraulic cylinders 7 and 8 with valve driving circuits 11 and 12, a device R1 which detects a turning angle of a steering wheel 5 and indicates a desired steering value theta is installed. In addition, a turnover amplifier A1, which turns over the polarity of output from this indication device R1 in relation to the output of a wheel neutral position setting device R0, is installed as well. Furthermore, deviation amplifiers A2 and A3, which amplify a differential portion lying between each output of devices R2 and R3 detecting the roll-steering values of both front and rear wheels 2 and 3 and the desired steering value passed through a steering mode select switch SW or output of the turnover amplifier A1, are installed whereby each of these solenoid valves 9 and 10 is controlled according to the output. |
