Abstract: In a valve apparatus, an annular contact portion made of elastic material is provided on a valve portion of a valve plug. A plurality of annular grooves are formed on a proximal end surface of a valve seat member which abuts against the contact portion. The annular grooves are formed around a communication hole through which fluid flows. The annular grooves have different diameters, and are concentric with one another.

Abstract: In a valve apparatus, an annular contact portion made of elastic material is provided on a valve portion of a valve plug. A plurality of annular grooves are formed on a proximal end surface of a valve seat member which abuts against the contact portion. The annular grooves are formed around a communication hole through which fluid flows. The annular grooves have different diameters, and are concentric with one another.

Abstract: A fluid passage valve is equipped with a valve body which is disposed rotatably through first and second shafts, a movable seat having a communication hole therein, and an elastic member that urges the movable seat toward a side opposite from the valve body. The first and second shafts are assembled and installed on the valve body such that an axis thereof is disposed at a position offset from a center of curvature of a spherical surface portion of the valve body. The fluid passage valve is placed in a valve-closed condition by the spherical surface portion abutting against a seating surface and closing the communication hole, and is placed in an open condition by the valve body separating away from the movable seat and thereby opening the communication hole.

Abstract: A fluid passage valve is equipped with a valve body which is disposed rotatably through first and second shafts, a movable seat having a communication hole therein, and an elastic member that urges the movable seat toward a side opposite from the valve body. The first and second shafts are assembled and installed on the valve body such that an axis thereof is disposed at a position offset from a center of curvature of a spherical surface portion of the valve body. The fluid passage valve is placed in a valve-closed condition by the spherical surface portion abutting against a seating surface and closing the communication hole, and is placed in an open condition by the valve body separating away from the movable seat and thereby opening the communication hole.

Abstract: An EGR valve includes a valve housing, a ball valve, a shaft, a valve holder held against the ball valve, and a valve seat. The valve holder includes a smaller-diameter portion, a larger-diameter portion, and an annular groove defined between the smaller-diameter portion and the larger-diameter portion. The annular groove is smaller in diameter than both the smaller-diameter portion and the larger-diameter portion. A chamber is defined between the annular groove and the valve housing.