| 摘要 |
PURPOSE:To realize quick switching of the rotational speeds and directions of an actuator and reduction of cost, by providing a main pipe line with a plural number of constant capacity pumps, circuit selecting means, and 1st and 2nd selecting means. CONSTITUTION:Main pipe lines 4, 5 are provided with a plural number of constand capacity pumps 2, 3, each of which is connected to suction pipes 2a1 to 2a3, 3a1 to 3a3 and disharge pipes 2b1, 3b1, respectevely and, to a tank 6 via a tail pipe 7. And said suction pipes are provided with directional switching valves 2c1 to 2c4, 3a1 to 3a4 respectively. Due to the above construction, by selecting an appropriate combination of each of said directional switching valves 2c1 to 2c4, 3c1 to 3c4, the directions of flow which runs through main pipe lines 4, 5 and return pipe lines can be changed and the amount of flow can be selected in many mays. Thus, quick switching of the rotatal speeds and directions of an actuator can be realized, and reduction of cost can be achieved.
|
