| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a driving device of a running motor capable of stopping both of right and left running motors when the drain pressure of at least one of the right and left running motors abnormally increases. SOLUTION: When the drain pressure of the first running motor 7 abnormally increases to exceed a designated pressure value, a pressure signal is given to switching valves 9, 10, 29, 30 by a first drain signal pipe 11 and a second drain signal pipe 31, to thereby switch the switching valves 9, 10, 29, 30. A first counterbalance 4 valve and a second counterbalance 24 valve are switched to the neutral position, the first running motor 7 and a second running motor 27 are stopped, hydraulic oil in a supply pipe 13 is returned to a hydraulic oil tank 2 by a first main relief valve 12, and oil pressure force in a supply pipe 33 is returned to the hydraulic oil tank 2 by a second main relief valve 32. Even if the drain pressure of the second running motor abnormally increases, both the first running motor 7 and the second running motor 27 are both stopped by the similar constitution.</p> |
