| 摘要 |
PURPOSE: To enable a delivery direction to change in a reversible variable displacement oil hydraulic pump, and to set a capacity to a value corresponding to an engine speed. CONSTITUTION: A device is constituted of a controlling oil hydraulic pump 3 of delivering a flow amount corresponding to a rotational speed of an engine 1, direction switching valve 40 of switching a circulating direction to circulate delivery pressure oil of the pump to a differential pressure generating circuit 47 and a servo controller 22 of controlling a direction and angle of tilting a swash plate 5 corresponding to a pressure difference before and after a throttle 48 of this differential pressure generating circuit 47. From a fact that a pressure difference before and after the throttle 48 of the differential pressure generating circuit 47 is in proportion to an engine speed, a capacity in accordance with the engine speed is obtained, and by making a direction opposite of circulating in the differential pressure generating circuit 47, a delivery direction is changed. |
