| 摘要 |
PROBLEM TO BE SOLVED: To provide a small steering device with a high safety which can change a steering direction smoothly against an automatic steering mode at a low cost. SOLUTION: An auxiliary hydraulic actuator 50 takes place the operation force of a first control valve 23 by hydraulic controlling of a pressed oil from a pump 37 by a second control valve 23' operated based on an outer signal. A hydraulic cylinder 18 takes place a steering auxiliary force for usual steering by the hydraulic control by the first control valve 23 operated based on the steering force of a driver and a hydraulic actuator 18 takes place the steering force for automatic steering by the hydraulic control by the first control valve 23 operated based on the generation force of an auxiliary hydraulic actuator 50. In the automatic steering mode, by exerting to the first control valve 23 without interfering the steering force of the driver with the generation force of the auxiliary hydraulic actuator 50, the hydraulic actuator 50 takes place the steering force in response to the sum of the operation amount of the first control valve 23 based on the steering force of the driver and the operation amount of the first control valve 23 based on the generation force of the auxiliary hydraulic actuator 50. |
