| 摘要 |
PURPOSE:To reduce loss of energy by controlling the discharge quantity of a variable capacity type pump to the minimum required flow during traveling and controlling the pump discharge quantity to the maximum flow according to an engine speed during working. CONSTITUTION:When a selector valve 15 is operated during traveling to put a power steering cylinder 14 in action, the presence of a throttle valve 3 is raised and applied to a cylinder small area chamber 9b1 and a cylinder large area chamber 9b2, therefore, the discharge quantity of a pump is controlled to the define minimum flow required regardless of the speed of an engine 1. When a selector valve 7a or 7b is operated during working, the cylinder large area chamber 9b2 is put in communication with a tank 11 through a duct 8 and only the pressure of a duct 5 is applied to the cylinder small area chamber 9b1. Accordingly, the discharge quantity of the pump can be controlled to the maximum flow corresponding to the speed of the engine 1. |
