Vehicular air conditioner having two-layered air flow

1. An air conditioner for vehicles having a two-layer air flow structure, air conditioner which comprises: an air-conditioning case having an air passageway, an indoor air inlet and an outdoor air inlet formed at an entrance side of the air passageway, the indoor air inlet and the outdoor air inlet being formed separately by a partition wall; and a plurality of air vents formed at an exit side of the air passageway;

an evaporator and a heater core mounted successively in the air passageway of the downstream side of the indoor air inlet and the outdoor air inlet, wherein the evaporator and the heater core are mounted so as to be spaced apart from each other by a predetermined distance;

a temperature control door rotatably mounted in the air passageway and located between the evaporator and the heater core for adjusting temperature by inducing air which has passed through the evaporator to pass through or to bypass the heater core;

whereby indoor air and outdoor air flow through the air passageway in a separated state from each other in a two-layer air flow mode,

wherein the temperature control door includes:

a rotary shaft rotatably mounted on the air-conditioning case;

a plate respectively formed on each of both sides of the rotary shaft, one plate being upstream of the rotary shaft and the other plate being downstream of the rotary shaft, each plate having two side edges; and

a pair of side walls respectively formed on both side edges of the upstream plate, said pair of side walls having end portions;

an auxiliary plate formed on the end portions of the side walls to open and close an air passageway bypassing the heater core, whereby the upstream plate, the pair of side walls, and the auxiliary plate together form a duct shape so that an air flow channel is formed through an inner space of the duct shape; and,

wherein the temperature control door further comprises a leak preventing device, the leak preventing device including an arc-shaped rib protruding from an outer surface of at least one of the side walls of the temperature control door, and a sliding groove formed on an inner surface of the air conditioning case for slidably inserting the rib therein.

2. The air conditioner for vehicles having a two-layer air flow structure according to claim 1 , wherein the air-conditioning case further includes a cold air bypass passageway formed at a downstream side of the evaporator to increase an air volume in a cooling mode, and a door for opening and closing the cold air bypass passageway, the cold air bypass passageway bypassing the heater core.