| 摘要 |
<p>The invention relates to a control valve apparatus (1) providing reciprocal motion, comprising a spool (2) and sleeve (3), a passage (4) for fluid, which is hydraulic fluid in the embodiment, the passage (4) being openable and closable by the spool (2) and sleeve (3), ports (A, B, C) for fluid, and at least one seal (5, 6), the arrangement being such that a seat of one seal (5) reacts with a seat of another (6) whereby to open the another seal (6).</p> |
