| 摘要 |
<p>PROBLEM TO BE SOLVED: To effectively prevent erosion of a seal by using a seal member made of rubber in a center valve. SOLUTION: A seat part for a seal is of double structure, i.e., an external side and internal side, and an external seal part 98 is made of rubber, and an internal seal part 94 is made of a material whose rigidity is higher than that of rubber. The seal parts 98, 94 are in the distance relationship in which the external seal part 98 is earlier seated than the internal seal part 94 relative to a poppet type valve element 72.</p> |
