| 摘要 |
<p>PROBLEM TO BE SOLVED: To exhibit a stable and high sealing performance, while enhancing the durability by preventing caught-in phenomena of an elastic material used for a seal member, when sealing a valve seat of a piston and a valve element of a center valve in a center valve type hydraulic pressure master cylinder for a vehicle. SOLUTION: The internal circumferential side of a seal face 34c of a valve element 34a is set to a plane crossing at right angles with a valve central axis, the outer circumferential side is set to a tapered face, and the outer circumferential edge 34d is chamfered into an arch shape. A first valve seat 50 is formed of an outside seal part 54 made of an elastic material and an inside seal part 55 using hard synthetic resin and metals. An elastic seal face 54a is so provided to the outside seal part 54 as to be taperedly enlarged in the valve element direction. The elastic seal face 54a and the outer circumferential edge 34d are opposed to each other so that the outer circumferential edge 34d of the seal face 34c of the valve element 34a is positioned adjacent to the intermediate part of the elastic seal face 54a. A rigid seal face 55a is sequentially provided on the counter side of the hydraulic chamber of the elastic seal face 54a in the direction crossing at right angles with the valve central axis. The rigid seal face 54a is opposed to the internal circumferential side of the seal face 34c of the valve element 34a.</p> |
