Abstract: An air passage open/close device includes a casing having an air passage, and a sliding door having a board member slidably located in the casing so as to open or close the air passage. The casing has a guide groove for guiding a movement of the board member. The guide groove has an upstream wall extending in a moving direction of the board member at an upstream side of the board member in an air flow direction, and a downstream wall opposing to the upstream wall at a downstream side of the board member in the air flow direction. The board member is configured to be elastically deformed when the board member is arranged in the casing.

Abstract: An air passage open/close device includes a casing having an air passage, and a sliding door having a board member slidably located in the casing so as to open or close the air passage. The casing has a guide groove for guiding a movement of the board member. The guide groove has an upstream wall extending in a moving direction of the board member at an upstream side of the board member in an air flow direction, and a downstream wall opposing to the upstream wall at a downstream side of the board member in the air flow direction. The board member is configured to be elastically deformed when the board member is arranged in the casing.

Abstract: An air passage opening and closing device includes a case forming an opening portion, a sliding door, and a gear mechanism. The case has a case-side seal surface at two edges of the opening portion in a width direction of a door body of the sliding door, on which a first plate surface of the door body abuts. The gear mechanism includes a driven side gear molded integrally with the door body using resin. The driven side gear protrudes from a second plate surface of the door body on a side opposite to the first plate surface, and extends in parallel with a movement direction of the sliding door, at two edge portions of the second plate surface in the width direction. In addition, the driven side gear has a hollow space opened toward a direction parallel to the width direction.