| 摘要 |
PURPOSE:To reduce quantity of working oil being fed from a hydraulic pump, by incorporating a piston for regulating the setting load according to a pressure difference into a flow control valve having spool valve structure being arranged in the way of a return oil path communicating between delivery side and suction side of a hydraulic pump. CONSTITUTION:A metering orifice 5 is arranged in the way of an oil supply path 4 communicating between a delivery port 1a of a hydraulic pump 1 and a power steering device 3, and a flow control valve 7 is arranged in the way of a return oil path 6 communicating between the downstream side of a metering orifice 5 and a suction port 1b of the hydraulic pump. The flow control valve 7 is constructed by fitting a spool valve body 11 slidably to a valve box 10 having an inlet and an outlet 8, 9 continuous to portions 6a, 6b at the upstream side and the downstream side of the return oil path 6. Here, one oil chamber 13 of a pair of oil chambers 12, 13 in the valve box 10 is partitioned into two chambers 15, 16 by means of a piston 14, where the first chamber 15 is communicated with an oil supply path 4 in the downstream of the metering orifice 5 and a changeover valve 26 is arranged between the second chamber 16, the chamber 15 and a hydraulic tank 2. |
