| 摘要 |
PURPOSE:To improve the interlocking action of a slewing base and a boom by using a system in which discharge pressure oil from a variable-capacity oil- pressure pump is preferentially supplied in parallel to a turning motor and a boom cylinder, and excessive oil is supplied to other actuators. CONSTITUTION:In the oil-pressure circuit of a back hoe A having a slewing base 1, a boom 2, an arm 3 and a bucket 4, the discharge pressure oil of a variable- capacity oil-pressure pump 11 is preferentially supplied in parallel to a turning motor 5 and a boom cylinder 6. The excessive pressure oil is supplied to other actuators 7 and 10 by a preferential type pressure compensating valve 27 provided in the upstream of the discharge pipeline of the oil-pressure pump 11. In concurrently operating the turning motor 5 and the boom cylinder 6, the pressure oil is supplied to the boom cylinder 6 and the turning motor 5 in a parallel manner. The interlocking action of the slewing base and the boom can thus be improved. |
