| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a driving device of a hydraulically operated motor in which a drain of a hydraulically operated motor has no bad influence on other hydraulically operated motors when drain pressure for either one of a plurality of hydraulically operated motors is abnormally increased at a high level. SOLUTION: If the drain pressure of the hydraulically operated motor 29 between the hydraulically operated motors 9 and 29 is abnormally increased at a high level, operating oil supplied to the hydraulically operated motor 29 returns to a tank 2 led through a first drain pipe 30, a second drain pipe 32, and a converged drain pipe 40 in a second hydraulic circuit 120. Then, a selector valve 11 is switched so that the drain pressure of the hydraulically operated motor 29 is given to a pilot chamber 11a of the selector valve 11 via a signal pipe 14. In a first hydraulic circuit 110, connection between a first drain pipe 10 and a second drain pipe 12 is blocked, the first drain pipe 10 and a third drain pipe 13 are connected each other, a drain of the hydraulically operated motor 9 returns to the tank 2 for operating oil led through the first drain pipe 10, the third drain pipe 13, a check valve 8, and a pipe 90b for low pressured oil flow.</p> |
