| 摘要 |
PURPOSE:To shorten the whole time which is necessary for opening a valve, and to enable position adjustment in speed reduction section, thereby to always enable smooth switching of a valve by connecting a second oil path hole which is closed by a pair of small pistons respectively to a pair of pilot ports. CONSTITUTION:Oil in a sleeve end chamber 28 of a piston unit portion 21 flows out without resistance from a pilot port P1 through oil path holes 24b and 24c of a sleeve 24 to a tank 12. Therefore, a small piston 27 on the left side retreats without resistance to the left, and it allows high speed moving of a main spool 3 to the left caused by pressing of a small piston 27 on the right side. The main spool 3 moves to the left by X which is the overlapped portion of land portions 3a and 3b on a sliding hole 20a of a body 20. And when the small piston 27 on the left side closes the oil path holes 24b and 24c, oil in the sleeve end chamber on the left side flows out from the oil path hole 24a through a throttle valve 34. |
