Patent ID: 7694729

Claim:
An air passage opening/closing device comprising: a casing assembly that defines an air passage, the casing assembly having a first casing and a second casing that are connected integrally with each other; a slide door movably disposed in the casing assembly to open and close the air passage; a driving device that moves the slide door; and a guide member formed independently from the casing assembly and separate from the casing assembly to define with the casing assembly a guide channel at each of two sides of the slide door in a direction substantially perpendicular to a moving direction of the slide door, the slide door slidingly engaging the guide channel defined by the guide member and the casing assembly; wherein: the guide member has a first door-sliding surface, and the first casing has a second door-sliding surface, the slide door slidingly engaging the first and second door-sliding surfaces; the first door-sliding surface of the guide member and the second door-sliding surface of the first casing are located opposite to each other and define the guide channel that guides the two sides of the slide door; the guide member has an approximately rectangular frame portion that defines therein a substantially rectangular opening through which air passes the guide member; a total length (L) of the slide door in the moving direction is shorter than a total length of the second door-sliding surface of the first casing; the slide door is stacked on the second door-sliding surface of the first casing; the guide member is stacked on the slide door; and the second casing is stacked on the guide member.