A valve includes a valve body having an exhaust gas inlet and an exhaust gas outlet, the valve body defining an exhaust gas circulation passage between the exhaust gas inlet and the exhaust gas outlet. A flap is arranged in the valve body and a shaft drives the flap in rotation with respect to the valve body. At least one guide bearing guides the drive shaft of the flap for rotation relative to the valve body. The guide bearing is engaged through an orifice of the valve body, with an inner end of the guide bearing being located inside the valve body. A first tube is engaged in one of the exhaust gas inlet and exhaust gas outlet and abuts against the inner end of the guide bearing.

A bearing holding structure has a substantially cylindrical sleeve and a plate-shaped pressing plate. A tubular portion of the sleeve includes a housing press-fit portion having an outer peripheral surface to be press-fit into a recess of an upper housing, and a bearing press-fit portion having an inner peripheral surface to be press-fit thereinto by a bearing. A pullout prevention portion that protrudes inward to prevent pullout of the bearing is formed at one end of the tubular portion, and the pressing plate is press-fit into the other end thereof.

A butterfly valve for controlling gas flow is disclosed. The butterfly valve may include a valve body, the valve body defining a bore and a shaft configured for rotatable motion with respect to the valve body and including a shoulder. The butterfly valve may further include a disk housed within the bore, operatively coupled with the shaft, and configured to control gas flow through the bore based on a rotational position of the shaft relative to the valve body. The butterfly valve may further include a ball bearing operatively coupled with the shaft and including a ball and a race. The butterfly may further includes a spring configured to provide an axial force on the shaft, the axial force configured to press the shoulder of the shaft against the race of the ball bearing to prevent an outer edge of the disk from contacting an inner wall of the bore.

A butterfly valve for controlling gas flow is disclosed. The butterfly valve may include a valve body, the valve body defining a bore and a shaft configured for rotatable motion with respect to the valve body and including a shoulder. The butterfly valve may further include a disk housed within the bore, operatively coupled with the shaft, and configured to control gas flow through the bore based on a rotational position of the shaft relative to the valve body. The butterfly valve may further include a ball bearing operatively coupled with the shaft and including a ball and a race. The butterfly may further includes a spring configured to provide an axial force on the shaft, the axial force configured to press the shoulder of the shaft against the race of the ball bearing to prevent an outer edge of the disk from contacting an inner wall of the bore.

A thrust plate for a butterfly valve includes a thrust plate body that defines a recess that extends between a bottom thrust surface, side walls, and an open top. There is a nickel-based or cobalt-based wear-resistant coating located on the bottom thrust surface. The wear-resistant coating is harder than the thrust plate body.

A valve device has a valve that opens and closes a passage, and a cantilever bearing member rotatably supporting a rotating shaft of the valve. The cantilever bearing member has rolling-element bearings arranged in series in an axial direction of the rotating shaft. One of the rolling-element bearings located the closest to the passage has a rolling element, an inner race, an outer race and a seal portion. A space is defined between the inner race and the outer race to receive the rolling element. The seal portion made of rubber tightly seals the space on a side adjacent to the passage.