Abstract: An air amount control valve is connected to a sidewall of a throttle body in which a main air passage for supplying intake air into an internal combustion engine is formed. The air amount control valve has a bypass air passage bypassing the main passage and controls an amount of air flowing through the bypass air passage, thereby controlling an idling speed of the engine. The air amount control valve includes an aluminum alloy housing having a valve hole and a rotatable valve body having a valve surface facing a fringe wall of the valve hole. To prevent deposits from adhering to the fringe wall facing the valve surface, an anodic oxide film is formed to cover the fringe wall and further a fluororesin film is formed on the anodic oxide film.

Abstract: A flow control valve comprises a first valve for controlling a radiator flow amount and a second valve for controlling a bypass flow amount. Pressure adjusting passages are respectively provided for the first and second valves for communicating spaces formed at both sides of the respective valves to equalize fluid pressures at both sides, so that a pressure load in an axial direction to the respective valves can be eliminated. As a result, a driving force of an actuator of the flow control valve for directly or indirectly driving the first and second valves can be reduced.

Abstract: An air amount control valve is connected to a sidewall of a throttle body in which a main air passage for supplying intake air into an internal combustion engine is formed. The air amount control valve has a bypass air passage bypassing the main passage and controls an amount of air flowing through the bypass air passage, thereby controlling an idling speed of the engine. The air amount control valve includes an aluminum alloy housing having a valve hole and a rotatable valve body having a valve surface facing a fringe wall of the valve hole. To prevent deposits from adhering to the fringe wall facing the valve surface, an anodic oxide film is formed to cover the fringe wall and further a fluororesin film is formed on the anodic oxide film.