| 摘要 |
PROBLEM TO BE SOLVED: To provide a steering device featuring high safety, low cost and small size, which can be smoothly changed from an automatic steering mode to a normal steering mode. SOLUTION: By hydraulic control of pressure oil from an oil pump 37 by a second control valve 23' actuated to be based on an external signal, an auxiliary hydraulic actuator 50 generates acting force of a first control valve 23. By hydraulic control by the first control valve 23 actuated to be based on steering force by a driver, normal steering assist force is generated in a hydraulic cylinder 18, by hydraulic control by the first control valve 23 actuated to be based on generating force of the auxiliary hydraulic actuator 50, automatic steering force is generated in a hydraulic actuator 18. To a normal steering mode, in which a relief oil path connecting the pump 37 and a tank 41 by an opening/closing valve 112 is opened by action of steering force of the driver in an automatic steering mode, a steering device is switched. |
