| 摘要 |
PROBLEM TO BE SOLVED: To provide a passage opening/closing valve capable of surely closing a fluid passage even if each member expands/contracts due to variation in temperature. SOLUTION: When a first abutting member 32 is seated in a first valve seat 22 and moreover a second abutting member 33 is seated on a second valve seat 28, an EGR(Exhaust Gas REFLUX) valve is closed, cutting off the communication between an exhaust gas inflow passage 100 and an exhaust gas outflow passage 101. A valve housing 20 is made of cast iron. The first valve seat 22 an the first abutting member 32 are formed by pressing a thin stainless steel plate to elastically deformable. The first valve seat 22 is provided with corner parts 22a, 22b forming a step between the outer peripheral side and the inner peripheral side. Thus, even if an outer peripheral annular part 23 deforms due to a difference in the coefficient of thermal expansion between the valve housing 20 and the first valve seat 22, the distorsion of the outer peripheral annular part 23 is prevented from being transmitted to the inner peripheral annular part 24, owing to the elastic deformation of the corner parts 22a, 22b.
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