| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve fluidity of operating fluid by securing a clearance for compensating the fluid formed between a rod part outer circumferential face and a central hole inner wall face of a valve element in a center valve mecha nism, lager compared with the conventional one and to eliminate any possibility of spoilling the seal performance, because the seating pose of the valve element relative to the valve seat becomes unstable caused by enlarging the clearance. SOLUTION: The outside diameter D2 of a pin member 21 is formed smaller than the inside diameter D1 of the central hole and larger than the outside diameter D3 of a rod part 13, and a guide part 28 performing sliding guide in the axial direction of the valve element 11 and regulating the diametrical movement is provided in a piston 3. A fluid communication passage to be a part of a communication passage between a fluid pressure chamber 6 and an operating fluid reservoir side is provided in the guide part 28.</p> |
