| 摘要 |
<p>A hydraulic directional-control valve comprises a first inlet port (11), a second inlet port (12), a tank port (28), a work port (29), and a valve member (21) which is movable from a neutral position to an operating position. In the neutral position the valve member (21) connects the first inlet port (11) with the tank port (28) and blocks the second inlet port (12), and in the operating position it blocks the first inlet port (11) and connects the second inlet port (12) with the work port (29). A third inlet port (13) is provided and the valve member (21) in the neutral position blocks the third inlet port and in the operating position connects it with the work port (29). The third inlet port (13) may be supplied with hydraulic fluid in parallel with the second inlet port (12) when an additional fluid flow is required.</p> |
