PROBLEM TO BE SOLVED: To simplify a reverse transmission constitution of a radiator fan for use in removing dusts at a dust protection net arranged at an outside air introduction part of a radiator and also enable an external power takeout constitution to be attained.SOLUTION: This invention is a work vehicle mover part structure including a tension change-over mechanism 35 for selectively applying tension to a normal rotation transmission belt 31 for cooperatively driving one of two-consecutive input pulleys 33 arranged at a fan shaft 19 and an inverse rotation transmission belt 32 for cooperatively driving the other pulley 33b through an inverse rotation transmission mechanism 18. Further, the inverse rotation transmission mechanism 18 comprises an input side shaft 21 cooperatively related to an engine output shaft 14； an output side shaft 22 arranged coaxially with the input side shaft 21； a bevel transmission mechanism 20 for cooperatively relating the normal rotation of the input side shaft 21 to the output side shaft 22； and an inverse rotation transmission shaft 24 arranged in parallel with the input side shaft 21 and the output side shaft 22 and cooperatively related to the output side shaft 22, the normal rotation transmission belt 31 is cooperatively related to the input side shaft 21 and the inverse rotation transmission belt 32 is cooperatively related to the inverse rotation transmission shaft 24.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2018,JPO&INPIT【課題】ラジエータの外気導入部に設ける防塵網の塵埃除去のためのラジエータファンの逆転伝動構成の簡素化を図る。併せて外部動力取出し構成を可能にしようとする。【解決手段】 ファン軸１９に設ける２連の入力プーリ３３の一方を連動する正転伝動ベルト３１と、逆転伝動機構１８を介して他方のプーリ３３ｂを連動する逆転伝動ベルト３２とを択一的に緊張するテンション切換機構３５を備えた作業車両の原動部構造とする。さらに前記逆転伝動機構１８は、エンジン出力軸１４に連動する入力側軸２１と、この入力側軸２１と同軸芯に設ける出力側軸２２と、入力側軸２１の正回転を出力側軸２２に逆回転に連動するベベル伝動機構２０と、入力側軸２１及び出力側軸２２と平行に設けられ該出力側軸２２に連動する逆転伝動軸２４とを備え、前記入力側軸２１に前記正転伝動ベルト３１を、前記逆転伝動軸２４に前記逆転伝動ベルト３２を連動させる。【選択図】 図３
