| 摘要 |
PURPOSE:To reduce the load of an engine during no use of auxiliary steering, by providing a load reducing means for reducing the load of a hydraulic pressure or the load of a drive source for driving the hydraulic pressure source when a hydraulic selector valve takes its neutral position. CONSTITUTION:A load reducing means 18 is provided between an oil pump 17 and a flow divider valve 19, and when the pressures of the pressure ports P of steering angle control valves 20, 21 are high, ports A, B of the load reducing means 18 are communicated with each other so that a discharged hydraulic pressure Qo from an oil pump 17 is fed to the steering angle control valves 20, 21. When the pressures of the pressure ports P of the steering angle control valves 20, 21 are low, that is, when they are set at their neutral positions so as to rest auxiliary steering, ports A, C of the load reducing means 18 are communicated together (however, the ports A, B are also maintained to be slightly communicated with each other) so as to drain the discharged hydraulic pressure Qo of the oil pump 17 with a slight loss. Accordingly, it is possible to lower the load of the oil pump 17. |
