The present invention relates to the driving part structures of working truck. Project to be solved is to provide a kind of mechanism that outside air is effectively drawn into using radiator fan. The project is solved by using such as flowering structure. Have the first fan (26) and configuration in the second fan (27) than first fan (26) on the inside of body, and it is equipped with the converting member (45) of the conversion of the rotation status for carrying out the first fan (26) and rotation halted state and the conversion of the rotation status of the second fan (27) and rotation halted state, so that it is corresponded to the rotation of the first fan (26) and stops and rotate the second fan (27).本發明涉及作業車輛的原動部結構。所要解決的課題是提供一種利用散熱器風扇有效地吸入外部空氣的機構。該課題通過採用如下結構來解決。具備第一風扇(26)和配置在比該第一風扇(26)靠機體內側的第二風扇(27)，並設有進行第一風扇(26)的旋轉狀態和旋轉停止狀態的轉換、和第二風扇(27)的旋轉狀態和旋轉停止狀態的轉換的轉換部件(45)，使其對應第一風扇(26)的旋轉停止而使第二風扇(27)旋轉。
