Patent ID: 8033899

Claim:
An air conditioning system for a cabin of a work vehicle comprising: a roof ( 7 ) of the cabin ( 1 ); and an air conditioning unit (A) arranged in a rear portion of the roof ( 7 ), wherein the roof ( 7 ) comprises a hollow outer roof ( 13 ) and an inner roof ( 14 ), the inner roof ( 14 ) has a rearward portion thereof formed as a low ceiling portion bulging downward, the outer roof ( 13 ) has a rearward portion thereof formed as an upward recess from a plane of joint with the inner roof ( 14 ), and the air conditioning unit (A) is provided in a space formed between the low ceiling portion and the recess, an air-conditioning duct ( 15 ) comprising right and left lateral air-conditioning ducts ( 15 B, 15 B) is located frontwardly with respect to the air conditioning unit (A) and in right and left lateral regions of the roof ( 7 ), which branches from the air conditioning unit (A) and extends to a front side of the roof ( 7 ), the inner roof ( 14 ) has right and left lateral portions as downward bulging portions, each of the right and left lateral air conditioning ducts ( 15 B, 15 B) is disposed in a space formed between the corresponding bulging portion of the inner roof ( 14 ) and a lower face of the outer roof ( 13 ), the system further comprises an interior air intake duct (a) for guiding interior air from the interior of the cabin ( 1 ) to the air conditioning unit (A), a circulation opening ( 14 A) for drawing air inside the cabin ( 1 ) into the air condition unit (A) is formed in a rear portion of a ceiling recess between the right and left downward bulging portions of the inner roof ( 14 ), and an ambient air feed opening ( 13 C) for drawing ambient air into the air condition unit (A) is formed in the lower face of the outer roof ( 13 ), the circulation opening ( 14 A) and the ambient air feed opening ( 13 C) being vertically opposed to each other, and a switching valve ( 17 ) switchable between a state in which the circulation opening ( 14 A) is opened and the ambient air feed opening ( 13 C) is closed and a state in which the circulation opening ( 14 A) is closed and the ambient air feed opening ( 13 C) is opened is supported swingably about a laterally extending axis at a position frontward of the circulation opening ( 14 A) and the ambient air feed opening ( 13 C).