Abstract: A guide groove is provided on both sides in a door width direction of a plate-like portion of a door. A radius of curvature of the plate-like portion in a single non-mounted state is set more than that of the guide groove, to thereby support both end portions in the door width direction of the plate-like portion respectively at three abutment points P1 to P3. A rib is provided in the plate-like portion to extend from one end portion in the door width direction of the plate-like portion to the other end portion thereof, so that force generated from both end portions in the door width direction of the plate-like portion is transferred to a center portion in the door width direction of the plate-like portion via the rib. Therefore, it can prevent the center portion and vicinity of the plate-like portion from being deformed in the direction away from a seal surface of the air conditioning case.

Abstract: An air passage opening and closing device includes: a sliding door configured to open and close an air passage using a plate-like portion disposed in an air-conditioning case; and a guide groove having a windward-side wall portion and a leeward-side wall portion. The plate-like portion includes: a first abutting portion positioned at an intermediate portion in a movement direction and abutting on the windward-side wall portion; two second abutting portions positioned on both sides of the first abutting portion in the movement direction and undergoing elastic deformation by abutting on one of the windward-side wall portion and the leeward-side wall portion; and two third abutting portions positioned on the both sides of the first abutting portion in the movement direction and pressed against and therefore abutting on the other wall portion on which the second abutting portions do not abut due to the elastic deformation of the second abutting portions.

Abstract: A guide groove is provided on both sides in a door width direction of a plate-like portion of a door. A radius of curvature of the plate-like portion in a single non-mounted state is set more than that of the guide groove, to thereby support both end portions in the door width direction of the plate-like portion respectively at three abutment points P1 to P3. A rib is provided in the plate-like portion to extend from one end portion in the door width direction of the plate-like portion to the other end portion thereof, so that force generated from both end portions in the door width direction of the plate-like portion is transferred to a center portion in the door width direction of the plate-like portion via the rib. Therefore, it can prevent the center portion and vicinity of the plate-like portion from being deformed in the direction away from a seal surface of the air conditioning case.