| 摘要 |
<p>PURPOSE:To make straight forward travelling possible when a boom is operated by short-circuiting both discharge passages of first and second pumps with first and second junction valves and a short-circuit passage, providing a left travelling valve and a boom valve respectively to the discharge passages of both pumps, and providing a right travelling valve on the side of the short- circuit passage. CONSTITUTION:When the first junction valve 24 is situated at the communicating position A and the second junction valve 34 at the cutoff position B, the discharge passage 20a of the first pump 20 is connected to a short-circuit passage 25, and discharge pressure oil is supplied respectively to left and right travel valves 22, 33. Also, the discharge pressure oil of the second pump 30 is supplied to a boom valve 31, thereby making the pressure of left and right travel motors equal and straight forward travelling possible when the boom is operated while travelling.</p> |
