PROBLEM TO BE SOLVED: To enable work to be restarted upon blowing-out dusts adhering to a filter at the time of restarting an engine, improve an output of the engine, and increase operation efficiency.SOLUTION: A cooling fan [20] and a dust removing fan [30] of which blade angles are set in reverse states are coaxially arranged. There are provided a cooling clutch [C1] for transmitting a driving force to the cooling fan [20] and a dust removing clutch [C2] for transmitting a driving force to the dust removing fan [30]. There is provided driving state changing-over means [45] for alternatively connecting both clutches [C1, C2] under a prescribed time interval. When cooling water temperature of a radiator [50] is lower than a set temperature at the time of starting engine [E], interval control is started from a connected state of the dust removing clutch [C2] and when a cooling water temperature of the radiator [50] is higher than a set temperature, the driving state changing-over means [45] is controlled in such a way that the operation is started from connection of the cooling clutch [C1].SELECTED DRAWING: Figure 10COPYRIGHT: (C)2017,JPO&INPIT【課題】エンジンの再始動時に、濾過体に付着した塵埃を吹き飛ばしてから作業を再開できるものとし、エンジンの出力を向上させ、作業能率を高める。【解決手段】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)を同一軸心上に設け、冷却ファン(20)へ駆動力を伝達する冷却クラッチ(C1)と、排塵ファン(30)へ駆動力を伝達する排塵クラッチ(C2)を設け、両クラッチ(C1,C2)を所定の時間間隔で交互に接続する駆動状態切換手段(45)を設け、エンジン(E)の始動時において、ラジエータ(50)の冷却水温が設定温度よりも低い場合には、インターバル制御が排塵クラッチ(C2)の接続から開始され、ラジエータ(50)の冷却水温が設定温度以上に高い場合には、冷却クラッチ(C1)の接続から開始されるように駆動状態切換手段(45)を制御する。【選択図】図10
