| 摘要 |
<p>In a hydraulic pressure pilot circuit which has a pilot pump which delivers pilot fluid and a plurality of pilot valves which control a plurality of hydraulic pressure selector valves by controlling the supply of the pilot fluid, the heating of the operating fluid which is caused by holding the pilot fluid is reduced and, even if a plurality of pilot valves are operated simultaneously, the pilot fluid can be sufficiently supplied to the pilot valves and the operatability is not deteriorated. A variable delivery pump is employed as the pilot pump. The operated states of the hydraulic pilot valves are detected by detecting means and the quantity of pilot fluid delivered which is necessary to operate the hydraulic pressure selector valves is calculated by a controller and only the required quantity of operating fluid is delivered by the pilot pump.</p> |
