| 摘要 |
<p>PURPOSE:To facilitate a running work by providing first, second, and third switching valve groups where a stack type switching valve has a switching valve for a working machine and a straight advancing control valve and a selection valve, located between the second and third switching groups. CONSTITUTION:When, through running of an engine, a first hydraulic pump or third hydraulic pumps 1, 2, and 3 and an auxiliary pump 4 are run, delivery oil from the first hydraulic pump 1 is fed to a pump port P1 of a connection plate A. Delivery oil from the second hydraulic pump 2 flows through a pump port P2, formed in a selection valve H, to a switching valve F for an arm, and flows through a joint passage 14 of a subplate E to a tank passage 6. Delivery oil from the third hydraulic pump 3 flow through a pump port P2 of a connection plate N to the passage 6 by means of a feed passage 9. This constitution maintains excellent straight advancing ability.</p> |
