| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology capable of changing an operation speed in a telescopic motion of a cylinder device according to a situation, with a simple constitution and high efficiency.SOLUTION: A pump device includes a first pump 101 having a first discharge portion 101a and a second discharge portion 101b, a first flow channel 111 connecting a first chamber Y1 of a cylinder and the first discharge portion 101a, a second flow channel 112 connecting a second chamber Y2 of the cylinder and the second discharge portion 101b, a second pump 102 having a third discharge portion 102a and a forth discharge portion 102b, a third flow channel 113 connecting the first chamber Y1 of the cylinder and the third discharge portion 102a, a forth flow channel 114 connecting the second chamber Y2 of the cylinder and the forth discharge portion 102b, a ninth flow channel 119 branched from the third flow channel 113 and reaching a tank 180, and a ninth flow channel opening/closing valve 145 disposed in the ninth flow channel 119, and opening the ninth flow channel 119 when a pressure of the second chamber Y2 of the cylinder is higher than a prescribed pressure.SELECTED DRAWING: Figure 4 |
