Patent ID: 6913529

Claim:
An air passage switching device comprising: a case for deforming an air passage through which air flows, the case having a first opening and a second opening through which air passes; and a rotary door that includes a rotation shaft, an outer peripheral door surface separated from a center axial line of the rotation shaft to a radial outside by a predetermined dimension, and two side plates connected to the rotation shaft and end portions of the outer peripheral door surface in an axial direction of the rotation shaft, wherein: the rotary door has first and second seal parts that are provided on periphery end portions of the side plates and the outer peripheral door surface, the first seal part being arranged at a side of the first opening, and the second seal part being arranged at a side of the second opening; the rotary door has a door structure angle (θd) defined by the first and second seal parts in a rotation direction of the rotary door, and the door structure angle is larger than a door operating angle (θm) in which the rotary door is rotatable around the rotation shaft; the case has a first end seal surface at a position proximate to the first opening and opposite to the second opening, a second end seal surface at a position proximate to the second opening and opposite to the first opening, and first and second middle seal surfaces between the first end seal surface and the second end seal surface in the rotation direction; the first and second middle seal surfaces are disposed to be separated from each other in the rotation direction by a predetermined angle that is a difference between the door structure angle and the door operating angle; when the rotary door is rotated to a first operation position where the first opening is closed, the first seal part press-contacts the first end seal surface, and the second seal part press-contacts the second middle seal surface; and when the rotary door is rotated to a second operation position where the second opening is closed, the first seal part press-contacts the first middle seal surface, and the second seal part press-contacts the second end seal surface.