| 摘要 |
<p>PURPOSE:To prevent the pressure in a pressure chamber from being leaked to a supply chamber and reduce the cost by providing a seal member having a first seal surface making contact with the outer circumferential surface of a valve seat member, a second seal surface making contact with the end surface of a piston, and a third seal surface making contact with the inner surface of a cylinder hole. CONSTITUTION:When a left pressing force is added to a piston 12, the piston 12 is moved to the left against the energizing force of a return spring 13, a valve seat part 23a makes contact with a valve body 22 to interrupt a communicating passage 18, and the pressure of the operating liquid in a pressure chamber R2 is raised in proportion to the pressing force added to the piston 12. In this case, since the sealings between the seat valve member 23 and the piston 12 and between a cylinder hole 11a and the piston 12 are simultaneously performed, the sealing between the pressure chamber R2 and a supply chamber R1 can be performed by one seat member 26. Since the piston 12 needs not to be integrated into the valve seat member 23 by press-fitting, no high dimensional precision is required.</p> |
