PROBLEM TO BE SOLVED: To improve working efficiency of a combine-harvester by causing dust adhered to the core of a radiator to fall, blowing out the falling dust, thereby increasing cooling efficiency of an engine.SOLUTION: A prime mover part of a combine-harvester is constituted in such a way that: radiator (50) is arranged outside an engine (E)； a filtration body (8B) filtering dust is arranged outside the radiator (50)； a cooling fan (20) and a dust-discharging fan (30) having blade angles set to be opposite to each other are rotatably provided on the same shaft center between the engine (E) and the radiator (50)； there are provided a cooling clutch (C1) connecting and interrupting transmission of a driving force from the engine (E) to the cooling fan (20), and a dust-discharging clutch (C2) connecting and interrupting transmission of a driving force from the engine (E) to the dust-discharging fan (30)； and a drive state switching means (45) is provided which switches a state of alternatively connecting the cooling clutch (C1) and the dust-discharging clutch (C2) and a state of connecting both of the cooling clutch (C1) and the dust-discharging clutch (C2).SELECTED DRAWING: Figure 10COPYRIGHT: (C)2018,JPO&INPIT【課題】ラジエータのコアに付着した塵埃を脱落させてから吹き飛ばし、エンジンの冷却効率を高めてコンバインの作業能率を向上させる。【解決手段】エンジン（Ｅ）の外側にラジエータ（５０）を配置し、ラジエータ（５０）の外側に塵埃を濾過する濾過体（８Ｂ）を配置し、エンジン（Ｅ）とラジエータ（５０）の間には、互いの翼角度を逆に設定した冷却ファン（２０）と排塵ファン（３０）を同一軸心上に回転自在に設け、エンジン（Ｅ）から冷却ファン（２０）への駆動力の伝達を接続および遮断する冷却クラッチ（Ｃ１）と、エンジン（Ｅ）から排塵ファン（３０）への駆動力の伝達を接続および遮断する排塵クラッチ（Ｃ２）を設け、冷却クラッチ（Ｃ１）と排塵クラッチ（Ｃ２）を択一的に接続する状態と冷却ファン（Ｃ１）と排塵クラッチ（Ｃ２）の両方を接続する状態とに切り換える駆動状態切換手段（４５）を設ける。【選択図】図１０
