| 摘要 |
PROBLEM TO BE SOLVED: To prevent an operating fluid from flowing to a steering cylinder during automatic steering by insert-connecting a solenoid selector valve actuated when switching from manual to automatic or from automatic to manual, into a hydraulic pipeline connecting a manual steering source to an automatic steering source. SOLUTION: In the case of manual steering, a handwheel is rotated in the direction of an arrow mark A by a manual side orbit roll 15 to feed an operating fluid from the first port side to a steering cylinder 17 via first and second pipeline 21, 22, a manual-automatic steering selector valve 14, a third pipeline 23, an eighth port to a ninth port of the manual side orbit roll 15, a fourth pipeline 24, a solenoid selector valve 16 and a fifth pipeline 25 so as to move a rod of the steering cylinder 17 in the direction of an arrow mark H. In the case of shifting to a automatic steering, a signal for shifting to automatic steering control is obtained from a guide to switch an automatic steering selector valve 14 and a solenoid selector valve 16 so as to cut off automatic and manual hydraulic circuits. |
