Problem to be solved: to increase the engine output by raising the temperature of the radiator of the working vehicle to an appropriate temperature to improve the working efficiency.Solution: a single fan (40) is disposed between the engine (20) and the radiator (30), and the driving force of the engine (20) is transmitted to the fan (40) and the first transmission path (W1) for normal rotation is transmitted to the fan (40), and the driving force of the engine (20) is transmitted to the fan (40), and vice versa The second transmission path (W2) and the transmission from the first transmission path (W1) to the fan (40) and the state in which the driving force is transmitted to the fan (40) from the second transmission path (W2) to the fanA power switching mechanism (60) and a power switching mechanism (60) for controlling the power switching mechanism (60) are provided so that the fan stop state in which no driving force is transmitted from the first degree of route (W1) and the second transmission path (W2) to the fan (40) can be generated.Diagram【課題】作業車両のラジエータ水温を早期に適正温度まで上昇させてエンジン出力を高め、作業能率を向上させる。【解決手段】 エンジン(20)とラジエータ(30)の間に単一のファン(40)を配置し、エンジン(20)の駆動力をファン(40)に伝動して正転駆動する第1の伝動経路(W1)と、エンジン(20)の駆動力をファン(40)に伝動して逆転駆動する第2の伝動経路(W2)と、第1の伝動経路(W1)からファン(40)へ駆動力を伝動する状態と前記第2の伝動経路(W2)からファン(40)へ駆動力を伝動する状態とに切り替える動力切替機構(60)と、動力切替機構(60)を制御して第1の伝度経路(W1)と第2の伝動経路(W2)のいずれからもファン(40)へ駆動力が伝動されないファン停止状態を現出可能な構成とする。【選択図】図2
