| 摘要 |
PROBLEM TO BE SOLVED: To prevent a stress fracture from being generated even when a rebounding member is kept in storage for a long time under a high load by molding a valve body in a resin with a specific tensile breaking point strength and specific bending modulus. SOLUTION: A valve mechanism is of such a construction that a seat part 6a is arranged, in a freely slidable manner, in the lower part of the inner wall on a protruding cylinder part 6 and brought into contact with a valve part 11a provided on a valve body 11 to be urged backward with the help of a rebounding member 10 such as a coil spring. The valve body 11 is protected against a stress fracture to be generated when it is kept in storage for a long time under the effects of a strong urging force (rebounding force) upon the valve body 11, by using a resin with a tensile breaking point strength of 200kg/cm<2> or more and a bending modulus of 4,000-15,000kg/cm<2> . |
