| 摘要 |
<p>PURPOSE:To prevent generation of a valve stick due to biting of a dust, by providing a groove or a step difference in the peripheral direction on a land of a spool in the control valve of an oil hydraulic actuator and forming a groovein a port part in the side of a valve body. CONSTITUTION:A spool 174 in the control valve of an oil hydraulic actuator forms in its land 174b a column-shaped equal contour part 174s and a cone- shaped contracting part 174t extended before and after said part 174s. And a transfer part, from the equal contour part 174s to the contracting part 174t, forms a groove 174m extending in the peripheral direction, which also a port 172b, opposed to said groove 174m, forms a groove 906 along the port. Consequently, a dust 900 contained in oil is all stored staying in the groove 174m, and the control valve eliminates biting of the dust in the spool, when it is moved, while obtains a stable flow of oil by the action of the groove 906 along the port.</p> |
