| 摘要 |
PROBLEM TO BE SOLVED: To improve operability of a workability vehicle, eliminate the fluctuation of a vehicle body during high-speed work, and safely execute work, by changing the steering quantity of steering wheels by a steering device according to detection of vehicle speed from a vehicle. SOLUTION: The proportional pressure control valves 46, 46 of an oil quantity regulating means are provided on the lower part side of the circuits of right and left oil passages 45R, 45L output from a steering unit 42. The proportional control valves 46 are constituted so that one parts on the oil passages 45R, 45L are always opened and the oil passages 45R, 45L are further largely opened by a command from a controller. When an operator rotationally moves a steering handle 1, working oil is let flow in a hydraulic cylinder 48 for steering front wheels so as to steer front wheels 22, but by changing a current value carried to the solenoid valves 46s, 46s of the proportional pressure control valves 46, 46 by means of the controller, the quantity of working oil flowing in the hydraulic cylinder 48 is controlled, and hence the steering quantity of the front wheels 2, 2 against the steering quantity of the steering handle 1 can be changed. |
