200949104 六、發明說明： 【發明所屬之技術領域】 本發明係有關一種設有排氣構造之動力單元’此排氣 構造供排出用於冷卻皮帶驅動式連續變速傳動裝置之空氣 【先前技術】 〇 車輛動力單元之皮帶驅動式連續變速傳動裝置例如已 知揭示於專利文獻1中。此動力單元包含配置於傳動箱中 曲柄軸之一側的皮帶驅動式連續變速傳動裝置。於此用於 皮帶驅動式連續變速傳動裝置之周知冷卻構造中’用於連 續變速傳動裝置之冷卻空氣入口形成於連續變速傳動裝置 側上傳動箱之一部分中，冷卻空氣出口形成於連續變速傳 動裝置側之對向側上傳動箱之下部中’且連接冷卻空氣入 口與冷卻空氣出口之冷卻空氣通路形成於傳動箱之下部中 ® 。由於冷卻空氣通路及冷卻空氣出口形成於傳動箱之下部 中，因此，有水及灰塵易於進入傳動箱之下部的問題。若 連續變速傳動裝置被水沾濕式，連續變速傳動裝置的壽命 即可能縮短。 專利文獻1 :日本專利61-40864 (第4及5頁） 【發明內容】 本發明欲解決之問題 本發明之目的在於提供一種設有用於皮帶驅動式連續 -5- 200949104 變速傳動裝置之排氣構造之動力單元，其中此動力單元設 有防止水及塵沙進入連續變速傳動裝置之冷卻空氣排氣通 路及冷卻空氣出口。 解決問題之手段 爲達成以上目的，本發明提供一種車輛動力單元，安 ^ 裝於車輛上，其內燃機之曲柄軸平行於車輛寬度橫向延伸 ，包括：曲柄軸箱，容納該內燃機之曲柄軸；皮帶驅動式 0 連續變速傳動裝置，包含：驅動軸，平行於該曲柄軸而延 伸，爲該曲柄軸所驅動；從動軸，平行於該曲柄軸；多數 帶輪，分別安裝於該驅動及從動軸上；以及皮帶，延伸於 該等帶輪間；以及傳動箱，容納該皮帶驅動式連續變速傳 動裝置，並具有冷卻空氣通路，用以冷卻該皮帶驅動式連 續變速傳動裝置之冷卻空氣被吸入其內，該傳動箱配置於 該曲柄軸之一側；該傳動箱包含：外傳動箱，形成該傳動 箱之一部分，並相對於平行於車輛寬度之橫向，自外側覆 Ο 蓋該皮帶驅動式連續變速傳動裝置：以及內傳動箱，形成 該傳動箱之另一部分，並附裝於該曲柄軸箱，俾相對於該 橫向，自內側覆蓋該皮帶驅動式連續變速傳動裝置；其中 該內傳動箱具有：冷卻空氣入口，吸入該傳動箱之冷卻空 氣被透過該冷卻空氣入口排出：排氣通路，設於該曲柄軸 箱之上部中以連接於該冷卻空氣入口，並實質上沿該橫向 延伸；以及下行通路，形成於該傳動裝置之對向側上該曲 柄軸箱之側壁中’並連接於該排氣通路。 -6 - 200949104 於車輛動力單元中，冷卻空氣排氣通路可與曲柄軸箱 一體形成。 較佳地，車輛動力單元計進一步包括：發電機，對向 安裝於該驅動軸上之帶輪，安裝於該曲柄軸之一部分上； 以及動力傳輸機構，用來將安裝在配置於該驅動帶輪後側 之從動軸上之帶輪的輸出動力傳輸至該動力單元所含用以 驅動車輛後輪之輸出軸；其中，自上方俯視，連接於排氣 ❹ 通路之下行通路形成於保持發電機之發電機保持部與自外 側覆蓋輸出軸之輸出軸容納部間之空腔中。 機油加油口形成於排氣通路之下行通路之出口附近， 潤滑油透過該機油加油口供入曲柄軸箱。 排氣通路之下行通路可由平行於車輛寬度而自曲柄軸 箱之外表面橫向向外延伸之肋以及自外側覆蓋肋之蓋所界 定。 較佳地，界定排氣通路之下行通路之蓋形成一輸出軸 蓋，其用以相對於平行於車輛寬度之方向自外側覆蓋動力 單元之輸出軸。 較佳地，界定排氣通路之壁形成用以強化動力單元吊 架突面之強化部。 發明之效果 根據本發明，皮帶驅動式連續變速傳動裝置之排氣通 路延伸入曲柄軸箱之上部，且排氣通路之下行通路於傳動 裝置側之對向側，沿曲柄軸箱之側表面設置。因此，可有 -7- 200949104 效防止灰塵及水經由排氣通路流入傳動箱。 排氣通路與曲柄軸箱一體形成可減少組成零件數。 當排氣通路之下行通路形成於保持發電機於內之發電 機保持部與自外側覆蓋輸出軸之輸出軸容納部間之空腔中 時，動力單元不會橫向鼓出，並可緊實形成。 當機油加油口形成於排氣通路之下行通路附近之空腔 中時，動力單元之組成構件不會平行於車輛寬度橫向突出 〇 當排氣通路之下行通路由平行於車輛寬度而從曲柄軸 箱之外表面橫向向外延伸之肋及從外側覆蓋此肋的蓋形成 時，下行通路可受到保護。 當形成排氣通路之下行通路之蓋形成相對於車輛寬度 自橫向外側覆蓋動力單元之輸出軸之蓋時，零件數可減少 〇 當形成排氣通路之周壁形成用於動力單元吊架突面之 強化構件時，可強化動力單元吊架突面。 G 【實施方式】 第1圖係摩托車1之側視圖，此摩托車1設有本發明 之動力單元20。摩托車1具有：本體2，於本體架之前端 包含車頭管3;主車架4，自車頭管3延伸以朝後方向下 傾斜；右及左樞支托架5，固定於該主車架4之後端部以 向下延伸；右及左座軌6，附裝於主車架4接近樞支托架 5前部之一部分，以朝後方向上傾斜，並分別具有彎曲中 -8- 200949104 間部；以及多數中間車架7，分別延伸於諸座軌6之中間 部與樞支托架5之間。 騎士乘坐之椅座8安裝於諸座軌6上，且容器9配置 於椅座8下。手把10藉車頭管3支撐於本體2之前部上 方，使之可轉動。前叉11自車頭管3向下延伸。前輪12 可旋轉地支撐於前叉11之下端部上。後叉14自樞支托架 5向後延伸。後叉14具有藉樞軸13樞支於樞支托架5上 G 之前端部，以及可旋轉地支撐後輪15之後端部。後叉14 在垂直於樞軸13的平面中上下擺動。多數後吸震器16分 別延伸於後叉1 4之諸後端部與諸座軌6之間。 動力單元20配置於主車架4下之一位置及樞支托架5 之前方，並自主車架4懸吊。動力單元20之上部藉自主 車架4之中間部向下延伸之支撐托架17懸吊。動力單元 20之二後部固定於此等樞支托架5。本體2以合成樹脂製 分部本體蓋18覆蓋。 ® 動力單元20包含形成動力單元20前部之內燃機21， 以及形成動力單元20後部之動力傳輸裝置22。內燃機21 係單汽缸四行程內燃機。內燃機21之汽缸單元以大角度 前傾，俾成水平姿勢向前突出。吸入管26自內燃機21向 上延伸，且節流閥本體27及用於內燃機21之進氣系統之 進氣清潔器28連接於吸入管26。自內燃機21向下延伸之 排氣管29折成向後延伸。配置於後輪15之右側之消音器 30連接於排氣管29之後端。驅動鏈輪32安裝於動力單元 20所含動力單元輸出軸31上。從動鏈輪33與後輪15組 -9- 200949104 合。動力傳輸鏈34延伸於驅動鏈輪32與從動鏈輪33間 以驅動後輪15。騎士用擱腳台122自動力單元20之下部 橫向向外延伸。機油加油口 127(第n圖）形成於擱腳台 122內側上之動力單元20之左側面，並以機油濾清器蓋 133覆蓋。 第2圖係自右側所取動力單元2〇之動力傳輸裝置22 之側視圖。該圖顯示動力傳輸裝置22之多數主軸、帶輪 及齒輪之個別位置。第2圖中144標示汽缸軸。內燃機21 Q 之曲柄軸37配置於曲柄軸箱25之前部。曲柄軸37之右 部作爲用於皮帶驅動式連續變速傳動裝置23之驅動軸38 。皮帶驅動式連續變速傳動裝置23所含從動軸39配置於 曲柄軸箱25之後部中。驅動帶輪40安裝於驅動軸38上 ，從動帶輪41安裝於從動軸39上，且V形皮帶42延伸 於驅動帶輪40與從動帶輪41之間。 濕式離心離合器43安裝於皮帶驅動式連續變速傳動 裝置23之從動軸39之左部上。濕式離心離合器43具有 〇 約等於從動帶輪41者之直徑。減速齒輪機構24包含離心 離合器—出齒輪76、減速齒輪中間軸45以及安裝於動力 單元輸出軸31上之多數齒輪。 參考第2圖，腳踏起動器機構46配置於曲柄軸箱25 之下部中。腳踏起動器機構46包含：腳踏起動器軸47’ 具有腳踏臂；第一中間軸48 ;第二中間軸49 ;安裝於第 二中間軸49上之多數齒輪；以及腳踏起動器從動齒輪50 ，安裝於曲柄軸37上。油栗125配設於曲柄軸37之前側 -10- 200949104 上，傾斜向下位移離開曲柄軸37之位置。起動器馬達18〇 配置於曲柄軸箱25之前部上。 第3圖係第2圖之III·III線上截面之展開圖。汽缸組 53、汽缸蓋54及搖臂室蓋55按此順序堆疊於曲柄軸箱25 之前表面上。活塞56裝入形成於汽缸組53之汽缸□徑 53a內，並藉連接桿57連接於曲柄軸37。活塞56於汽缸 口徑53a內往復運動。 Ο 內燃機21設有SHOC型閥系統。閥系58以搖臂室蓋 55覆蓋。閥系58藉曲柄軸37，透過曲柄軸驅動鏈59驅 動。燃燒室60形成於連結於汽缸組53之汽缸蓋54之端 面。火星塞61自汽缸蓋54之右側插入汽缸蓋54。 動力單元20之動力傳輸裝置22之外殻包含：曲柄軸 箱25，由左曲柄軸箱25L及右曲柄軸箱25R構成；發電 機蓋62，連結於左曲柄軸箱25L之左側；以及傳輸箱63 ，連結於右曲柄軸箱25之右側；並包含內傳輸箱63A及 ® 外傳輸箱63B。此等箱及蓋爲鑄件。 曲柄軸室65及連通或續接曲柄軸室65之減速齒輪室 66形成於曲柄軸箱25所界定之空間內。曲柄軸37沿平行 於車輛寬度之方向，亦即橫向延伸，並被支承成於左曲柄 軸箱25L及右曲柄軸箱25R上之諸軸承中旋轉。減速齒輪 機構24所含齒輪系的齒輪配置於減速齒輪室66中。 左曲柄軸箱25L及發電機蓋62之間界定一發電機室 67。曲柄軸驅動鏈輪68、電動起動器從動齒輪69及交流 變電機70安裝在延伸於發電機室67中之曲柄軸37的一 -11 - 200949104 部分。 離心離合器室71界定於右曲柄軸箱25R與內傳輸箱 63A之間。藉導流板72將連結內傳輸箱63A與外傳輸箱 63B而形成之傳輸箱63中之空間分成傳動室73及導氣室 74。曲柄軸37之右部經由離心離合器室71並經由裝入內 傳輸箱63A之開口中之密封構件75而伸入傳動室73。腳 踏起動器從動齒輪50藉多數栓槽，與伸入離心離合器室 71中之曲柄軸37之一部分聯鎖。伸入傳動室73中之曲柄 ⑬ 軸37之一部分用來作爲皮帶驅動式連續變速傳動裝置23 之驅動軸38。皮帶驅動式連續變速傳動裝置23之驅動帶 輪40安裝於驅動軸38上。 皮帶驅動式連續變速傳動裝置23之從動軸39配置於 驅動軸38的後面。從動軸39被支承於右曲柄軸箱25R及 內傳輸箱63A上之多數軸承中。皮帶驅動式連續變速傳動 裝置23之從動帶輪41安裝於伸入傳動室73之從動軸39 之一部分。濕式離心離合器43及離合器輸出齒輪76安裝 〇 於伸入離心離合器室71中之從動軸39之一部分上。軸承 密封構件77裝入形成於內傳輸箱63A中之開口以保持支 承驅動軸39之軸承。 皮帶驅動式連續變速傳動裝置23之驅動帶輪40包含 固定部78及活動部79。活動部79與驅動軸38 —起旋轉 ，並可藉利用離心力徑向向外移動之配重滾子80,軸向朝 向或遠離固定部78。如此，V形皮帶42繞驅動帶輪40處 之驅動帶輪40之節圓之節徑改變。 -12- 200949104 皮帶驅動式連續變速傳動裝置23之從動帶輪41包含 固定部81及活動部82。活動部82藉位於固定部81右側 之環形滑件83支承於套筒84上。藉螺旋彈簧85將活動 部82壓至左側。當V形皮帶42保持於繞驅動帶輪40之 諸部78與79間處之驅動帶輪40之節圓之節徑增加時， 從動帶輪41之部分81與82間之距離抵抗螺旋彈簧85之 壓力而而增加’且節圓之直徑因自動連續變速改變而減少 〇 濕式離心離合器43安裝於延伸入離心離合器室71之 從動軸39之左部。濕式離心離合器43具有：內構件87， 其具有藉花鍵而與從動軸39聯鎖之內構件87;以及多數 離合器回位彈簧89，被支承以在附裝於內構件87之周部 之銷88上擺動。 離合器輸出齒輪76藉滾針軸承支承於從動軸39之左 端部，俾相對於從動軸39旋轉。濕式離心離合器43具有 外構件90，該外構件90具有固定於離合器輸出齒輪76之 突面之中央部。在從動軸39之轉速上升超過預定轉速時 ，離合器回位彈簧89與外構件90啣合以旋轉外構件90。 結果，離合器輸出齒輪76與外構件90 —起旋轉。 減速齒輪機構24配置於皮帶式連續變速傳動裝置23 之從動軸39與配置在從動軸39後部之動力單元輸出軸31 間。減速齒輪機構24之減速齒輪中間軸45支承於左曲柄 軸箱25L及右曲柄軸箱25R上的軸承中。齒輪91安裝於 延伸入離心離合器室71之減速齒輪中間軸45之一部分上 -13- 200949104 ，並與離合器輸出齒輪76啣合。小齒輪92與延伸入減速 齒輪室66中之減速齒輪中間軸45之一部分形成爲一體。 動力單元輸出軸31支承於左曲柄軸箱25L及右曲柄 軸箱25R上的軸承中。齒輪93安裝於延伸入減速齒輪室 66中之動力單元輸出軸31之一部分上，並與小齒輪92嚙 合，該小齒輪92與減速齒輪中間軸45形成爲一體。驅動 鏈輪32安裝於動力單元輸出軸31之一部分上，該動力單 元輸出軸31自左曲柄軸箱25L向左突出。驅動鏈34捲繞 @ 於驅動鏈輪32上。離合器輸出齒輪76之旋轉以減低之轉 速透過減速齒輪中間軸45傳輸至動力單元輸出軸31。離 合器輸出齒輪76之旋轉透過安裝於動力單元輸出軸31之 左端部上之驅動鏈輪32及動力傳輸鏈34(第1圖）傳輸至 後輪1 5。 參考第2圖，腳踏起動器機構46配置於曲柄軸37及 濕式離心離合器43下方。腳踏起動器軸47配置於皮帶驅 動式連續變速傳動裝置23之從動軸39下方。 © 第4圖係於第2圖中線IV-IV之截面之展開圖。腳踏 起動器軸47可旋轉地支撐於續接曲柄軸室65之腳踏起動 器齒輪室95中左曲柄軸箱25L及右曲柄軸箱25R上。腳 踏起動器軸47之左端部延伸經過左曲柄軸箱25L之厚、 圓筒形軸承部96，並自左曲柄軸箱25L向左突出。腳踏 臂98之底端部附接於腳踏起動器軸47自左曲柄軸箱25L 突出之部分。踏板106附接於腳踏臂98之自由端。腳踏 起動器軸47之右端部支撐於右曲柄軸箱25R上。回復彈 -14- 200949104 簧97捲繞腳踏起動器軸47之右端部，俾將腳踏起動器軸 47與腳踏臂98 —起轉動至起動位置。止動件99附接於腳 踏起動器軸47之右端部以保持腳踏臂98於預定起動位置 〇 大徑之腳踏起動器驅動齒輪1 0 0藉花鍵，與腳踏起動 器軸47接近軸承部96之一部分聯鎖。第一中間軸48配 置於腳踏起動器軸47前面，並可旋轉地支撐於左曲柄軸 〇 箱25L及右曲柄軸箱25R上。第一中間小齒輪101與第一 中間軸48—體形成。第一中間齒輪1〇2藉花鍵，與第一 中間軸4 8聯鎖。第一中間小齒輪1 〇 1與腳踏起動器驅動 齒輪1〇〇嚙合。 第二中間軸49配置於第一中間軸48前面，並可旋轉 地支撐於左曲柄軸箱25L、右曲柄軸箱25R及內傳動箱 63A上。第二中間軸49穿過右曲柄軸箱25R以延伸入曲 柄軸室65及離心離合器室71兩者中。第二中間小齒輪 ® 1〇3形成在位於接近第二中間軸49之被支撐左端部之第二 中間軸49上。第二中間小齒輪103與第一中間齒輪102 嚙合。 從動螺旋齒輪機構105安裝於第二中間軸49延伸入 離心離合器室71之部分上。從動螺旋齒輪機構1〇5容許 第二中間軸49沿一方向之旋轉被傳輸至可相對於第二中 間軸49旋轉之第二中間齒輪104，且不容許第二中間軸 49沿一相對方向之旋轉被傳輸至第二中間齒輪1 〇4。第二 中間齒輪104與腳踏起動器從動齒輪50嚙合，該腳踏起 -15- 200949104 動器從動齒輪50藉花鍵，與曲柄軸37聯鎖。 當如以上所述，下壓腳踏起動器機構46之踏板106 時，透過第一中間軸48、安裝於第二中間軸49上之齒輪 及從動螺旋齒輪機構105，將施加至踏板1〇6之驅動力傳 輸至腳踏起動器從動齒輪50,以強力旋轉曲柄軸37。 參考第4圖，動力單元20設有電動起動機構107。電 動起動機構107包含起動器馬達108、形成於起動器馬達 108之旋轉軸中之驅動小齒輪109、安裝於電動起動器中 ❹ 間軸110上之齒輪111及小齒輪112、安裝於曲柄軸37之 左部上之馬達起動器從動齒輪69以及介設於馬達起動器 從動齒輪69與曲柄軸37間之單向離合器113。起動起動 器馬達108以強力旋轉曲柄軸37。 參考第3圖，第一空氣通路115形成於外傳動箱63B 之後上部中。氣流經由第一空氣通路115流入傳動箱63。 如上所述，導流板72固定保持於外傳動箱63B內部，俾 傳動箱63之內部被導流板72分成傳動室73及導氣室74 〇 〇 第5圖係自右側所視，於外傳動箱63B之外壁與導流 板72間之平面所取外傳動箱63B之縱剖視圖。第一空氣 通路115形成於外傳動箱63B之後上部。空氣經由第一空 氣通路115流入傳動箱63。導流板72延伸於外傳動箱 63 B之實質上整個內表面的上方。導流板72配置在皮帶 驅動式連續變速傳動裝置23相對於車輛寬度之橫切外側 上。第二空氣通路116(亦參考第3圖）形成於導流板72對 -16- 200949104 向驅動軸38之端部的一部分。空氣自導氣室74經由第二 空氣通路116流入傳動室73。開口 117(第3圖）形成於導 流板72對向從動軸39之一部分。從動軸39之一端部延 伸通過開口 1 17。圓筒壁1 18(第3圖）自外傳動箱63B之 內表面突出至開口 117之邊緣。因此，空氣不會流經開口 117。壁138自外傳動箱63B朝導流板72之周邊突出（第3 及4圖）。基本上，由於壁138接觸導流板72，因此，空 ❹ 氣不會流經導流板72之周邊而進入開口 117。然而’空氣 卻可能略微流經導流板72之周邊。 如於第3圖所示，驅動帶輪40之固定部78設有多數 導氣片119。當驅動帶輪40旋轉時，空氣從導氣室74被 強力吸入傳動室73。由於驅動帶輪40之固定部78設有多 數導氣片119，因此，導氣片119保持與導流板72隔固定 距離，且空氣可穩定吸入。從動帶輪41之固定部81亦設 有多數導氣片125，俾諸帶輪可被有效冷卻。 © 如於第1圖所示，用以空氣冷卻連續變速傳動裝置之 冷卻空氣清潔器12〇連接於後本體蓋18中第一空氣通路 115之上游端。冷卻空氣清潔器120及進氣清潔器28係個 別空氣清潔器。由於第一空氣通路115形成於動力單元20 之後上部，因此，即使連續變速傳動裝置用冷卻空氣清潔 器120未設於第一空氣通路115之上游端，渣子及塵粒仍 難以往前進入第一空氣通路115。雖然連續變速傳動裝置 用冷卻空氣清潔器120將渣子及塵粒移除至某一程度，即 使動力單元20未設有連續變速傳動裝置用冷卻空氣清潔 -17- 200949104 器120，當空氣於導氣室74中自第一空氣通路n5流入 二空氣通路116時’渣子及塵粒卻仍與空氣分離。由於 一空氣通路115與第二空氣清潔器相互分離，因此，當 氣自連續變速傳動裝置用冷卻空氣清潔器120流至第一 氣通路115時，渣子及塵粒易與空氣分離。通過第一空 通路115之冷卻空氣121朝導氣室74之下部流動。因 ’冷卻空氣121流經導氣室74之下部，且渣子及塵粒 與導氣室74中的冷卻空氣121分離。 如於第1圖所示，爲騎士而設之擱腳台122自動力 元20之傳輸箱62之側壁橫向向外延伸。傳輸箱62之 壁藉空氣冷卻’且藉導氣室74隔離連續變速傳動裝置 所產生的熱。因此，駕駛的腳不會覺得熱，且騎士可舒 地騎乘摩托車。 第6圖係自左側所示’外傳動箱63B之左連結表面 傳動室73內部之視圖。於第6圖中顯示驅動軸38、安 於驅動軸38上之驅動帶輪40、從動軸39、安裝於從動 39上之從動帶輪41以及延伸於配置在外傳動箱63B之 壁內部之帶輪40與41間的V形皮帶41。排氣通路入 導肋63Ba形成於外傳動箱63B之上部，俾將冷卻空 121導入內傳動箱63A之排氣通路124。200949104 VI. Description of the Invention: [Technical Field] The present invention relates to a power unit provided with an exhaust structure for exhausting air for cooling a belt-driven continuously variable transmission. [Prior Art] A belt-driven continuously variable transmission of a vehicle power unit is known, for example, from Patent Document 1. This power unit consists of a belt-driven continuously variable transmission that is placed on one side of the crankshaft in the gearbox. In the well-known cooling structure for a belt-driven continuously variable transmission, the cooling air inlet for the continuously variable transmission is formed in a portion of the transmission case on the side of the continuously variable transmission, and the cooling air outlet is formed in the continuously variable transmission A cooling air passage connecting the cooling air inlet and the cooling air outlet in the lower portion of the gearbox on the opposite side of the side is formed in the lower part of the transmission case. Since the cooling air passage and the cooling air outlet are formed in the lower portion of the transmission case, there is a problem that water and dust easily enter the lower portion of the transmission case. If the continuously variable transmission is wetted by water, the life of the continuously variable transmission may be shortened. Patent Document 1: Japanese Patent No. 61-40864 (pages 4 and 5) SUMMARY OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is to provide an exhaust gas provided for a belt-driven continuous-5-200949104 variable speed transmission device. The power unit is constructed, wherein the power unit is provided with a cooling air exhaust passage and a cooling air outlet for preventing water and dust from entering the continuously variable transmission. Means for Solving the Problems In order to achieve the above object, the present invention provides a vehicle power unit mounted on a vehicle, wherein a crankshaft of the internal combustion engine extends laterally parallel to the width of the vehicle, including: a crankcase, a crankshaft for accommodating the internal combustion engine; The driven type 0 continuously variable transmission includes: a drive shaft extending parallel to the crank shaft for driving the crank shaft; a driven shaft parallel to the crank shaft; and a plurality of pulleys respectively mounted on the drive and the driven And a belt extending between the pulleys; and a gearbox accommodating the belt-driven continuously variable transmission and having a cooling air passage for cooling the cooling air of the belt-driven continuously variable transmission The transmission case is disposed on one side of the crankshaft; the transmission case includes: an outer transmission case forming a part of the transmission case, and the belt-driven type is covered from the outer side with respect to a lateral direction parallel to the width of the vehicle Continuously variable transmission: and an internal transmission case forming another part of the transmission case and attached to the crankcase, 俾For the lateral direction, the belt-driven continuously variable transmission is covered from the inner side; wherein the inner transmission case has a cooling air inlet through which cooling air sucked into the transmission box is exhausted: an exhaust passage is provided in the crank An upper portion of the axle box is coupled to the cooling air inlet and extends substantially in the lateral direction; and a downward passage is formed in the side wall of the crank axle box on the opposite side of the transmission device and is coupled to the exhaust passage . -6 - 200949104 In the vehicle power unit, the cooling air exhaust passage can be formed integrally with the crankcase. Preferably, the vehicle power unit further includes: a generator, a pulley mounted opposite to the drive shaft, mounted on a portion of the crankshaft; and a power transmission mechanism for mounting on the drive belt The output power of the pulley on the driven shaft on the rear side of the wheel is transmitted to the output shaft of the power unit for driving the rear wheel of the vehicle; wherein, viewed from above, the passage connected to the exhaust passage is formed in the transmission The generator holding portion of the motor and the outer casing cover the output shaft housing portion of the output shaft. The oil filler port is formed near the outlet of the exhaust passage below the exhaust passage, and the lubricating oil is supplied to the crankcase through the oil filler port. The under passage of the exhaust passage may be defined by ribs extending laterally outward from the outer surface of the crankcase parallel to the width of the vehicle and from the cover of the outer cover ribs. Preferably, the cover defining the passageway below the exhaust passage forms an output shaft cover for covering the output shaft of the power unit from the outside with respect to the direction parallel to the width of the vehicle. Preferably, the wall defining the exhaust passage forms a reinforcement for reinforcing the power unit hanger projection. EFFECTS OF THE INVENTION According to the present invention, the exhaust passage of the belt-driven continuously variable transmission extends into the upper portion of the crankcase, and the passage below the exhaust passage is on the opposite side of the transmission side, along the side surface of the crankcase . Therefore, there is a -7-200949104 effect to prevent dust and water from flowing into the gearbox via the exhaust passage. The exhaust passage is integrally formed with the crankcase to reduce the number of components. When the exhaust passage is formed in a cavity between the generator holding portion that holds the generator and the output shaft housing portion that covers the output shaft from the outside, the power unit does not bulge laterally and can be formed tightly. . When the oil filler port is formed in the cavity near the exhaust passage under the exhaust passage, the constituent members of the power unit do not protrude laterally parallel to the width of the vehicle. When the exhaust passage is below the exhaust passage, the passage is parallel to the width of the vehicle from the crankcase The downward passage can be protected when the outer surface extends laterally outwardly from the rib and the cover that covers the rib from the outside. When the cover forming the passage under the exhaust passage forms a cover covering the output shaft of the power unit from the laterally outer side with respect to the width of the vehicle, the number of parts can be reduced. When the peripheral wall forming the exhaust passage is formed for the power unit hanger protrusion When the component is strengthened, the power unit hanger protrusion surface can be strengthened. [Embodiment] Fig. 1 is a side view of a motorcycle 1, which is provided with a power unit 20 of the present invention. The motorcycle 1 has a body 2 including a head tube 3 at a front end of the body frame, a main frame 4 extending from the head tube 3 to be inclined downward toward the rear, and right and left pivot brackets 5 fixed to the main frame 4, the rear end extends downward; the right and left seat rails 6, attached to the main frame 4 close to a part of the front part of the pivot bracket 5, are inclined in the rearward direction, and have curved mid--8-200949104 respectively And a plurality of intermediate frames 7 extending between the intermediate portions of the seat rails 6 and the pivot brackets 5, respectively. The rider seat 8 is mounted on the seat rails 6, and the container 9 is disposed under the seat 8. The handle 10 is supported by the front tube 3 above the front portion of the body 2 to be rotatable. The front fork 11 extends downward from the head pipe 3. The front wheel 12 is rotatably supported on the lower end of the front fork 11. The rear fork 14 extends rearward from the pivot bracket 5. The rear fork 14 has a pivot end 13 pivotally supported on the front end of the pivot bracket 5 on the G, and rotatably supports the rear end of the rear wheel 15. The rear fork 14 swings up and down in a plane perpendicular to the pivot 13. Most of the rear shock absorbers 16 extend between the rear ends of the rear forks 14 and the land rails 6, respectively. The power unit 20 is disposed at a position below the main frame 4 and in front of the pivot bracket 5, and the autonomous frame 4 is suspended. The upper portion of the power unit 20 is suspended by a support bracket 17 extending downward from the intermediate portion of the autonomous frame 4. The rear portion of the power unit 20 bis is fixed to the pivot brackets 5. The body 2 is covered with a synthetic resin partial body cover 18. The power unit 20 includes an internal combustion engine 21 that forms the front of the power unit 20, and a power transmission device 22 that forms the rear of the power unit 20. The internal combustion engine 21 is a single-cylinder four-stroke internal combustion engine. The cylinder unit of the internal combustion engine 21 is tilted forward at a large angle and protrudes in a horizontal posture to protrude forward. The suction pipe 26 extends upward from the internal combustion engine 21, and the throttle body 27 and the intake cleaner 28 for the intake system of the internal combustion engine 21 are connected to the suction pipe 26. The exhaust pipe 29 extending downward from the internal combustion engine 21 is folded to extend rearward. The muffler 30 disposed on the right side of the rear wheel 15 is connected to the rear end of the exhaust pipe 29. The drive sprocket 32 is mounted on the power unit output shaft 31 included in the power unit 20. The driven sprocket 33 is combined with the rear wheel 15 group -9-200949104. The power transmission chain 34 extends between the drive sprocket 32 and the driven sprocket 33 to drive the rear wheel 15. The knight's footrest 122 automatically extends outwardly from the lower portion of the force unit 20. The oil filler port 127 (Fig. n) is formed on the left side of the power unit 20 on the inner side of the footrest 122, and is covered by the oil filter cover 133. Fig. 2 is a side view of the power transmission device 22 of the power unit 2 taken from the right side. The figure shows the individual positions of the majority of the spindle, pulley and gear of the power transmission device 22. In Figure 2, 144 indicates the cylinder axis. The crankshaft 37 of the internal combustion engine 21 Q is disposed in front of the crankcase 25. The right portion of the crankshaft 37 serves as a drive shaft 38 for the belt-driven continuously variable transmission 23. The driven shaft 39 included in the belt-driven continuously variable transmission 23 is disposed in the rear portion of the crankcase 25. The drive pulley 40 is mounted on the drive shaft 38, and the driven pulley 41 is mounted on the driven shaft 39, and the V-belt 42 extends between the drive pulley 40 and the driven pulley 41. The wet centrifugal clutch 43 is mounted on the left side of the driven shaft 39 of the belt-driven continuously variable transmission 23. The wet centrifugal clutch 43 has a diameter which is approximately equal to that of the driven pulley 41. The reduction gear mechanism 24 includes a centrifugal clutch-out gear 76, a reduction gear intermediate shaft 45, and a plurality of gears mounted on the power unit output shaft 31. Referring to Fig. 2, the kick starter mechanism 46 is disposed in the lower portion of the crankcase 25. The kick starter mechanism 46 includes: the kick starter shaft 47' has a pedal arm; a first intermediate shaft 48; a second intermediate shaft 49; a plurality of gears mounted on the second intermediate shaft 49; and a kick starter The moving gear 50 is mounted on the crankshaft 37. The oil pump 125 is disposed on the front side of the crankshaft 37, -10-200949104, and is displaced obliquely downward from the position of the crankshaft 37. The starter motor 18 is disposed on the front portion of the crankcase 25. Figure 3 is an expanded view of the section on the III.III line of Figure 2. The cylinder block 53, the cylinder head 54 and the rocker chamber cover 55 are stacked on the front surface of the crankcase 25 in this order. The piston 56 is housed in a cylinder diameter 53a formed in the cylinder group 53, and is coupled to the crank shaft 37 by a connecting rod 57. The piston 56 reciprocates within the cylinder bore 53a.内燃机 The internal combustion engine 21 is provided with a SHOC type valve system. Valve train 58 is covered by rocker chamber cover 55. Valve train 58 is driven by crankshaft drive chain 59 via crankshaft 37. The combustion chamber 60 is formed at an end face of the cylinder head 54 coupled to the cylinder block 53. The Mars plug 61 is inserted into the cylinder head 54 from the right side of the cylinder head 54. The outer casing of the power transmission device 22 of the power unit 20 includes: a crank axle box 25 composed of a left crank axle box 25L and a right crank axle box 25R; a generator cover 62 coupled to the left side of the left crank axle box 25L; and a transmission box 63, connected to the right side of the right crank axle box 25; and includes an inner transmission box 63A and an outer transmission box 63B. These boxes and covers are castings. The crank chamber 65 and the reduction gear chamber 66 that communicates or continually extends the crank chamber 65 are formed in the space defined by the crankcase 25. The crankshaft 37 extends in a direction parallel to the width of the vehicle, i.e., laterally, and is supported to rotate in the bearings on the left crank axle box 25L and the right crank axle box 25R. The gear of the gear train included in the reduction gear mechanism 24 is disposed in the reduction gear chamber 66. A generator chamber 67 is defined between the left crank axle box 25L and the generator cover 62. The crankshaft drive sprocket 68, the electric starter driven gear 69, and the AC motor 70 are mounted in a portion -11 - 200949104 of the crankshaft 37 extending in the generator chamber 67. The centrifugal clutch chamber 71 is defined between the right crank axle box 25R and the inner transfer case 63A. The space in the transmission case 63 formed by joining the inner transfer case 63A and the outer transfer case 63B is divided by the deflector 72 into the transmission chamber 73 and the air guide chamber 74. The right portion of the crankshaft 37 extends into the transmission chamber 73 via the centrifugal clutch chamber 71 and via a sealing member 75 that is inserted into the opening of the inner transfer case 63A. The pedal starter driven gear 50 is interlocked with a portion of the crank shaft 37 that projects into the centrifugal clutch chamber 71 by a plurality of bolt slots. A portion of the crank 13 shaft 37 that projects into the transmission chamber 73 is used as the drive shaft 38 of the belt driven continuously variable transmission 23. The drive pulley 40 of the belt-driven continuously variable transmission 23 is mounted on the drive shaft 38. The driven shaft 39 of the belt-driven continuously variable transmission 23 is disposed behind the drive shaft 38. The driven shaft 39 is supported in a plurality of bearings on the right crankcase 25R and the inner transfer case 63A. The driven pulley 41 of the belt-driven continuously variable transmission 23 is mounted to a portion of the driven shaft 39 that projects into the transmission chamber 73. The wet centrifugal clutch 43 and the clutch output gear 76 are mounted on a portion of the driven shaft 39 that projects into the centrifugal clutch chamber 71. The bearing sealing member 77 is fitted into the opening formed in the inner transfer case 63A to hold the bearing that supports the drive shaft 39. The drive pulley 40 of the belt-driven continuously variable transmission 23 includes a fixed portion 78 and a movable portion 79. The movable portion 79 rotates together with the drive shaft 38, and can be axially moved toward or away from the fixed portion 78 by a weight roller 80 that moves radially outward by centrifugal force. Thus, the V-belt 42 changes around the pitch of the pitch circle of the drive pulley 40 at the drive pulley 40. -12- 200949104 The driven pulley 41 of the belt-driven continuously variable transmission 23 includes a fixed portion 81 and a movable portion 82. The movable portion 82 is supported by the sleeve 84 by an annular slider 83 located on the right side of the fixed portion 81. The movable portion 82 is pressed to the left side by a coil spring 85. When the V-belt 42 is held around the pitch of the drive pulley 40 between the portions 78 and 79 of the drive pulley 40, the distance between the portions 81 and 82 of the driven pulley 41 resists the coil spring. The pressure of 85 is increased by 'and the diameter of the pitch circle is reduced by the automatic continuous shifting change. The damped centrifugal clutch 43 is mounted to the left portion of the driven shaft 39 that extends into the centrifugal clutch chamber 71. The wet centrifugal clutch 43 has an inner member 87 having an inner member 87 interlocked with the driven shaft 39 by a spline, and a plurality of clutch return springs 89 supported to be attached to the periphery of the inner member 87. The pin 88 swings. The clutch output gear 76 is supported by the left end of the driven shaft 39 by a needle bearing, and is rotated relative to the driven shaft 39. The wet centrifugal clutch 43 has an outer member 90 having a central portion fixed to a projection surface of the clutch output gear 76. When the rotational speed of the driven shaft 39 rises above a predetermined rotational speed, the clutch return spring 89 engages with the outer member 90 to rotate the outer member 90. As a result, the clutch output gear 76 rotates with the outer member 90. The reduction gear mechanism 24 is disposed between the driven shaft 39 of the belt type continuously variable transmission 23 and the power unit output shaft 31 disposed at the rear of the driven shaft 39. The reduction gear intermediate shaft 45 of the reduction gear mechanism 24 is supported in bearings on the left crank axle housing 25L and the right crank axle housing 25R. The gear 91 is mounted on a portion of the reduction gear intermediate shaft 45 that extends into the centrifugal clutch chamber 71 -13 - 200949104 and engages the clutch output gear 76. The pinion gear 92 is integrally formed with a portion of the reduction gear intermediate shaft 45 that extends into the reduction gear chamber 66. The power unit output shaft 31 is supported in bearings on the left crank axle housing 25L and the right crank axle housing 25R. The gear 93 is mounted on a portion of the power unit output shaft 31 that extends into the reduction gear chamber 66 and is engaged with the pinion 92, which is formed integrally with the reduction gear intermediate shaft 45. The drive sprocket 32 is mounted on a portion of the power unit output shaft 31 which projects leftward from the left crank axle box 25L. The drive chain 34 is wound around @ on the drive sprocket 32. The rotation of the clutch output gear 76 is transmitted to the power unit output shaft 31 through the reduction gear intermediate shaft 45 at a reduced speed. The rotation of the clutch output gear 76 is transmitted to the rear wheel 15 through the drive sprocket 32 and the power transmission chain 34 (Fig. 1) attached to the left end portion of the power unit output shaft 31. Referring to Fig. 2, the kick starter mechanism 46 is disposed below the crankshaft 37 and the wet centrifugal clutch 43. The kick starter shaft 47 is disposed below the driven shaft 39 of the belt drive type continuously variable transmission 23. © Fig. 4 is an expanded view of the section of line IV-IV in Fig. 2. The pedal starter shaft 47 is rotatably supported on the left crank axle box 25L and the right crank axle box 25R in the kick starter gear chamber 95 of the crankshaft chamber 65. The left end portion of the pedal starter shaft 47 extends through the thick, cylindrical bearing portion 96 of the left crank axle housing 25L and protrudes leftward from the left crank axle housing 25L. The bottom end of the pedal arm 98 is attached to a portion of the pedal starter shaft 47 that protrudes from the left crank axle box 25L. The pedal 106 is attached to the free end of the pedal arm 98. The right end portion of the pedal starter shaft 47 is supported on the right crank axle box 25R. Resilience -14- 200949104 The spring 97 winds the right end of the pedal starter shaft 47, and rotates the pedal starter shaft 47 and the pedal arm 98 to the starting position. A stopper 99 is attached to the right end of the kick starter shaft 47 to hold the pedal arm 98 at a predetermined starting position, a large diameter pedal starter drive gear 110, a spline, and a kick starter shaft 47. A portion of the bearing portion 96 is interlocked. The first intermediate shaft 48 is disposed in front of the kick starter shaft 47 and rotatably supported on the left crank axle box 25L and the right crank axle box 25R. The first intermediate pinion 101 is formed integrally with the first intermediate shaft 48. The first intermediate gear 1〇2 is interlocked with the first intermediate shaft 4 8 by a spline. The first intermediate pinion 1 〇 1 is engaged with the pedal starter drive gear 1〇〇. The second intermediate shaft 49 is disposed in front of the first intermediate shaft 48 and rotatably supported on the left crank axle housing 25L, the right crank axle housing 25R, and the inner transmission case 63A. The second intermediate shaft 49 passes through the right crank axle box 25R to extend into both the crank shaft chamber 65 and the centrifugal clutch chamber 71. The second intermediate pinion ® 1〇3 is formed on the second intermediate shaft 49 located near the supported left end of the second intermediate shaft 49. The second intermediate pinion 103 meshes with the first intermediate gear 102. The driven helical gear mechanism 105 is mounted on a portion of the second intermediate shaft 49 that extends into the centrifugal clutch chamber 71. The driven helical gear mechanism 1〇5 allows the second intermediate shaft 49 to be transmitted in one direction to the second intermediate gear 104 rotatable relative to the second intermediate shaft 49, and does not allow the second intermediate shaft 49 to follow an opposite direction The rotation is transmitted to the second intermediate gear 1 〇4. The second intermediate gear 104 meshes with the kick starter driven gear 50, which is interlocked with the crank shaft 37 by a spline -15-200949104 driven gear 50. When the pedal 106 of the kick starter mechanism 46 is depressed as described above, the first intermediate shaft 48, the gear mounted on the second intermediate shaft 49, and the driven helical gear mechanism 105 are applied to the pedal 1〇. The driving force of 6 is transmitted to the kick starter driven gear 50 to strongly rotate the crank shaft 37. Referring to Fig. 4, the power unit 20 is provided with an electric starting mechanism 107. The electric starting mechanism 107 includes a starter motor 108, a drive pinion 109 formed in a rotating shaft of the starter motor 108, a gear 111 and a pinion 112 attached to the inter-shaft 110 in the electric starter, and is mounted to the crankshaft 37. A motor starter driven gear 69 on the left side and a one-way clutch 113 interposed between the motor starter driven gear 69 and the crankshaft 37. The starter motor 108 is started to rotate the crankshaft 37 with a strong force. Referring to Fig. 3, the first air passage 115 is formed in the upper portion after the outer transmission case 63B. The air flow flows into the transmission case 63 via the first air passage 115. As described above, the deflector 72 is fixedly held inside the outer transmission case 63B, and the inside of the transmission case 63 is divided by the deflector 72 into the transmission chamber 73 and the air guiding chamber 74. The fifth picture is viewed from the right side. A longitudinal cross-sectional view of the outer transmission case 63B taken from the plane between the outer wall of the transmission case 63B and the deflector 72. The first air passage 115 is formed at an upper portion after the outer transmission case 63B. Air flows into the transmission case 63 via the first air passage 115. The deflector 72 extends above substantially the entire inner surface of the outer gearbox 63B. The deflector 72 is disposed on the lateral side of the belt-driven continuously variable transmission 23 with respect to the width of the vehicle. The second air passage 116 (also referred to in Fig. 3) is formed in a portion of the end of the baffle 72 facing the drive shaft 38 from -16 to 200949104. The air self-guided plenum 74 flows into the transmission chamber 73 via the second air passage 116. The opening 117 (Fig. 3) is formed in a portion of the deflector 72 facing the driven shaft 39. One end of the driven shaft 39 extends through the opening 1 17 . The cylindrical wall 18 (Fig. 3) projects from the inner surface of the outer transmission case 63B to the edge of the opening 117. Therefore, air does not flow through the opening 117. The wall 138 protrudes from the outer transmission case 63B toward the periphery of the deflector 72 (Figs. 3 and 4). Basically, since the wall 138 contacts the deflector 72, the air does not flow through the periphery of the deflector 72 and enters the opening 117. However, the air may flow slightly through the periphery of the baffle 72. As shown in Fig. 3, the fixing portion 78 of the drive pulley 40 is provided with a plurality of air guide sheets 119. When the drive pulley 40 rotates, air is strongly drawn from the air guide chamber 74 into the transmission chamber 73. Since the fixing portion 78 of the driving pulley 40 is provided with a plurality of air guiding sheets 119, the air guiding sheets 119 are kept at a fixed distance from the deflector 72, and the air can be stably sucked. The fixed portion 81 of the driven pulley 41 is also provided with a plurality of air guide fins 125, and the pulleys can be effectively cooled. © As shown in Fig. 1, a cooling air cleaner 12 for air-cooling the continuously variable transmission is coupled to the upstream end of the first air passage 115 in the rear body cover 18. The cooling air cleaner 120 and the air intake cleaner 28 are separate air cleaners. Since the first air passage 115 is formed at the upper portion after the power unit 20, even if the continuous-speed transmission cooling air cleaner 120 is not disposed at the upstream end of the first air passage 115, the slag and the dust particles are difficult to enter the first step. Air passage 115. Although the continuously variable transmission uses the cooling air cleaner 120 to remove the slag and dust particles to a certain extent, even if the power unit 20 is not provided with the continuously variable transmission, the cooling air is cleaned -17-200949104 120, when the air is in the air When the chamber 74 flows into the two air passages 116 from the first air passage n5, the slag and the dust particles are still separated from the air. Since the air passage 115 and the second air cleaner are separated from each other, when the air flows from the continuously variable transmission to the first air passage 115 by the cooling air cleaner 120, the slag and the dust particles are easily separated from the air. The cooling air 121 passing through the first empty passage 115 flows toward the lower portion of the air guide chamber 74. Since the cooling air 121 flows through the lower portion of the air guiding chamber 74, the slag and the dust particles are separated from the cooling air 121 in the air guiding chamber 74. As shown in Fig. 1, the side wall of the transfer case 62 of the automatic footrest 122 for the knight is extended laterally outward. The wall of the transfer box 62 is cooled by air' and the plenum 74 isolates the heat generated by the continuously variable transmission. Therefore, the driving feet do not feel hot, and the knight can ride the motorcycle comfortably. Fig. 6 is a view showing the inside of the left joint surface transmission chamber 73 of the outer transmission case 63B shown from the left side. In Fig. 6, a drive shaft 38, a drive pulley 40 mounted on the drive shaft 38, a driven shaft 39, a driven pulley 41 mounted on the driven 39, and a wall disposed inside the outer transmission case 63B are shown. A V-belt 41 between the pulleys 40 and 41. The exhaust passage guide rib 63Ba is formed on the upper portion of the outer transmission case 63B, and the cooling air 121 is introduced into the exhaust passage 124 of the inner transmission case 63A.
第7圖係自右側所示，內傳動箱63A之右連結表面 傳動室73內部之視圖。於第7圖中顯示係驅動軸38、 裝於驅動軸38上之驅動帶輪4〇、從動軸39、安裝於從 軸39上之從動帶輪41以及延伸於配置在內傳動箱63A 第 第 空 空 氣 此 易 單 側 23 適 及 裝 軸 周 P 氣 及 安 動 之 200949104 示排氣通路124之截面。 第1 〇圖係自左側所視左曲柄軸箱2 5 L之左側視圖 於第10圖中顯示曲柄軸37、凸輪軸從動鏈59、凸輪軸 緊張機構126、機油加油口 127、輸出軸31、驅動鏈輪 、動力傳輸鏈34及腳踏起動軸47。排氣通路124形成 左曲柄軸箱25L之上部。圖示排氣通路124之截面。 空氣導肋130配置於排氣通路124之下方。輸出軸 〇 護肋131形成於輸出軸31上以環繞輸出軸31之前部。 第10圖中二點鏈線所示後動力單元蓋132覆蓋容納排 通路124、排氣通路124之下行通路135、輸出軸31、 動鏈輪32及動力傳輸鏈34之繞驅動鏈輪32之部分的 間。後動力單元蓋132設有對應機油加油口 127之開 132a，使機油加油口 127不被覆蓋。 第11圖係於第10圖之XI-XI上所取截面圖。外傳 箱63B、內傳動箱63A、右曲柄軸箱25R、左曲柄軸 ® 25L及後動力單元蓋132之截面按第11圖中自右至左 順序配置。分別形成於此等殼件之上部之排氣通路124 諸零件連結在一起以形成排氣通路124。透過排氣通 124將所用冷卻空氣121排出。機油加油口 127以設有 位計之機油濾清蓋133覆蓋。機油濾清蓋133經由後動 單元蓋132之開口 132a向外突出。後動力單元蓋132 有用來將注油器之凸部導引至機油加油口 127導壁132b 冷卻空氣121自傳動室73經過空氣入口 123流入排氣 路124並流至排氣通路124中的左側。接著，冷卻空 鏈 32 於 保 以 氣 驅 空 P 動 箱 之 之 路 油 力 具 〇 通 氣 -20- 200949104 周壁內部之帶輪40與41間的V形皮帶42。排氣 口導肋63 Aa形成於內傳動箱63A之上部。排氣通 之結面顯示於空氣入口 123後方。排氣通路入 63 Aa形成於內傳動箱63 Α之上部，俾將冷卻空氣 入排氣通路124。 第8圖係右曲柄軸箱25R之右連結表面及離心 室71內部之視圖。於第8圖中顯示曲柄軸37之延 安裝於曲柄軸37之延伸部上之腳踏起動器從動齒寧 第二腳踏起動器中間軸49、第二中間齒輪104、腳 器機構46之從動螺旋齒輪機構105、從動軸39、 心離合器43、離合器輸出齒輪76、減速齒輪中間幸 動力單元20之動力單元輸出軸31及配置於右曲 25R之周壁內部之油泵125以及起動器馬達108。 離冷卻空氣之排氣通路124形成於右曲柄軸箱25R 。圖示排氣通路124之截面。界定排氣通路124之 亦作爲用於動力單元吊架突面139之強化構件。 第9圖係左曲柄軸箱25L與曲柄軸室65之內 踏起動器齒輪室95與減速齒輪室66之右連結表面 。於第9圖中顯示曲柄軸37、曲柄腹板3 7a、腳踏 機構46之腳踏起動器軸47、腳踏起動器驅動齒輪 第一中間軸48、第一中間小齒輪1 0 1、第一中間齒 、第二中間軸49、第二中間小齒輪103、減速齒輪5 之中間軸45、小齒輪92、輸出軸31、齒輪93及起 達108。排氣通路124形成於左曲柄軸箱25L之上 通路入 路124 口導肋 121導 離合器 伸部、 命50、 踏起動 濕式離 由45、 柄軸箱 用以驅 之上部 壁140 部、腳 之視圖 起動器 100 ' 輪102 機構24 動器馬 部。圖 200949104 121碰撞後動力單元蓋132而轉向以向下流動。接 卻空氣121向下流經形成於左曲柄軸箱25L與後動 蓋132間之下行通路135，並經由空氣出口 136排 中〇 參考第10圖，冷卻空氣121向下流經空氣導肋 輸出軸保護肋131及機油加油口 127所界定之下 135，並經由空氣出口 136排出。排氣通路124之 〇 路135藉後動力單元蓋132保護。 參考第3圖，機油加油口 127形成於發電機 134與輸出軸保護肋131間之空腔中。後動力單元 覆蓋該空腔除了機油加油口 127之部分。續接排 124之下行通路135形成於機油加油口 127後方。 視，下行通路135形成於曲柄軸箱25之發電機保持 與輸出軸保護肋131間之空腔中。因此，動力單元 件不會橫向鼓出。由於機油加油口 127配置在空腔 ® 油加油口 127及機油濾清蓋133不會橫向鼓出。 參考第10圖，機油加油口 127配置於發電機 134與腳踏起動軸47間之空腔中。因此，機油加油 及機油濾清蓋133不會鼓出，從而，動力單元20 形成。 上述實施例具有以下效果。 (1)由於用於皮帶驅動式連續變速傳動裝置23 通路124延伸於曲柄軸箱25之上部中，且排氣通 之下行通路1 3 5形成於排氣通路1 24側之對向側的 著，冷 力單元 入大氣 130、 行通路 下行通 保持部 蓋 132 氣通路 由上俯 部134 之諸構 中，機 保持部 口 127 可緊實 之排氣 路124 曲柄軸 -21 - 200949104 箱25之側壁上，因此，可有效避免塵埃及水流經排氣通 路124而進入傳動箱63。 (2) 由於排氣通路124與左曲柄軸箱25L、右曲柄軸箱 25R及內傳動箱63A形成爲一體，因此，零件數可減少。 (3) 由於由上俯視，下行通路135形成於發電機室67 與保持曲柄軸箱25之輸出軸31之保持部保護肋131間之 空腔中，因此，動力單元20不會橫向鼓出，並可緊實形成 。 ❹ (4) 由於機油加油口 127形成於接近下行通路135之空 腔中，因此，動力單元20之諸零件不會橫向鼓出。 (5) 由於下行通路135由空氣導肋130、自左曲柄軸箱 25L之側壁橫向向外突出之輸出軸保護肋131以及覆蓋此 等肋之後動力單元蓋132所界定，因此’下行通路135受 到保護。 (6) 由於後動力單元蓋132自外側覆蓋下行通路135及 動力輸出軸31兩者，因此，零件數可減少。 Ο (7) 由於界定排氣通路124之周壁140亦用來作爲強化 動力單元吊架突面139之強化構件，因此，可強化動力單 元吊架突面139。 【圖式簡單說明】 第1圖係設有本發明較佳實施例之動力單元之摩托車 的側視圖； 第2圖係自摩托車右側所動力單元之立體圖； -22- 200949104 第3圖係於第2圖中線ΠI-III之截面之展開圖； 第4圖係於第2圖中線IV-IV之截面之展開圖； 第5圖係自右側所視，於外傳動箱之外壁與導流板間 之平面所取外傳動箱之縱剖視圖； 第6圖係自左側所視，傳動箱之左連結表面及傳動室 內部之視圖； 第7圖係自右側所視，內傳動箱之右連結表面及傳動 © 室內部之視圖； 第8圖係右曲柄軸箱之右連結表面及離心離合器室內 部之視圖； 第9圖係左曲柄軸箱之右連結表面、曲柄軸箱內部及 用於腳踏起動器機構之齒輪室內部之視圖； 第1 〇圖係自左側所視左曲柄軸箱之側視圖；以及 第11圖係沿第1 0圖中線XI-XI所取剖視圖。 〇 【主要元件符號說明】 23:皮帶驅動式連續變速傳動裝置 24 :減速齒輪機構 25 :曲柄軸箱 25L :左曲柄軸箱 25R:右曲柄軸箱 4〇 :驅動帶輪 41 :從動帶輪 42 : V形皮帶 -23- 200949104 4 3 :濕式離心離合器 62 :發電機蓋 63 :傳輸箱 63 A :內傳輸箱 63B :外傳輸箱 6 5 :外傳輸箱 66 :曲柄軸室 67 :發電機室 7 1 :離心離合器室 72 :折流擋板 73 :傳動室 74 :導氣室 95:腳踏起動器齒輪室 1 1 5 :第一空氣通路 1 16 :第二空氣通路 1 1 7 :從動軸中之孔 1 2 1 :冷卻空氣 122 :擱腳台 1 23 :空氣入口 124 :排氣通路 1 2 7 :機油加油口 130 :空氣導肋 131 :輸出軸護肋 :後動力單元蓋 -24 132 200949104Fig. 7 is a view showing the inside of the transmission case 73 from the right connecting surface of the inner transmission case 63A as shown from the right side. In Fig. 7, a drive shaft 38, a drive pulley 4 mounted on the drive shaft 38, a driven shaft 39, a driven pulley 41 mounted on the slave shaft 39, and an extension gearbox 63A are shown. The first empty air is easy to unilaterally 23. It is suitable for the shaft circumference P gas and the safety of 200949104 shows the cross section of the exhaust passage 124. 1 is a left side view of the left crankcase 2 5 L from the left side. The crankshaft 37, the camshaft driven chain 59, the camshaft tensioning mechanism 126, the oil filler port 127, and the output shaft 31 are shown in FIG. The drive sprocket, the power transmission chain 34 and the kick start shaft 47. The exhaust passage 124 forms an upper portion of the left crankcase 25L. A cross section of the exhaust passage 124 is illustrated. The air guiding rib 130 is disposed below the exhaust passage 124. The output shaft 〇 guard rib 131 is formed on the output shaft 31 to surround the front portion of the output shaft 31. The rear power unit cover 132, which is shown by the two-dot chain line in FIG. 10, covers the accommodating passage 124, the exhaust passage 124, the output passage 135, the output shaft 31, the movable sprocket 32, and the power transmission chain 34 around the drive sprocket 32. Part of the room. The rear power unit cover 132 is provided with an opening 132a corresponding to the oil filler port 127 so that the oil filler port 127 is not covered. Figure 11 is a cross-sectional view taken on XI-XI of Figure 10. The cross sections of the outer transfer box 63B, the inner transmission case 63A, the right crank case 25R, the left crank shaft ® 25L, and the rear power unit cover 132 are arranged in order from right to left in Fig. 11. The exhaust passages 124, which are respectively formed on the upper portions of the casings, are joined together to form an exhaust passage 124. The cooling air 121 used is discharged through the exhaust passage 124. The oil filler port 127 is covered by an oil filter cover 133 having a position. The oil filter cover 133 protrudes outward through the opening 132a of the rear unit cover 132. The rear power unit cover 132 is used to guide the convex portion of the oiler to the oil filler port 127. The guide wall 132b. The cooling air 121 flows from the transmission chamber 73 through the air inlet 123 into the exhaust passage 124 and flows to the left side of the exhaust passage 124. Next, the cooling air chain 32 is used to protect the air from the P-moving box. The oil-carrying belt -20-200949104 The V-belt 42 between the pulleys 40 and 41 inside the peripheral wall. The exhaust port guide rib 63 Aa is formed on the upper portion of the inner transmission case 63A. The junction of the exhaust passage is shown behind the air inlet 123. The exhaust passage 63 Aa is formed on the upper portion of the inner transmission case 63, and the cooling air is introduced into the exhaust passage 124. Fig. 8 is a view showing the right connecting surface of the right crankcase 25R and the inside of the centrifugal chamber 71. The pedal starter of the crankshaft 37 extending on the extension of the crankshaft 37 is shown in Fig. 8 as the second pedal starter intermediate shaft 49, the second intermediate gear 104, and the foot mechanism 46. The driven helical gear mechanism 105, the driven shaft 39, the core clutch 43, the clutch output gear 76, the power unit output shaft 31 of the reduction gear intermediate power unit 20, and the oil pump 125 and the starter motor disposed inside the peripheral wall of the right curve 25R 108. An exhaust passage 124 from the cooling air is formed in the right crankcase 25R. A cross section of the exhaust passage 124 is illustrated. The exhaust passage 124 is also defined as a reinforcing member for the power unit hanger projection 139. Figure 9 is a diagram showing the right connecting surface of the left crankcase 25L and the crankshaft chamber 65 between the starter gear chamber 95 and the reduction gear chamber 66. In Fig. 9, the crankshaft 37, the crank web 37a, the pedal starter shaft 47 of the pedal mechanism 46, the pedal starter drive gear first intermediate shaft 48, the first intermediate pinion 1 0 1 , the first An intermediate tooth, a second intermediate shaft 49, a second intermediate pinion 103, an intermediate shaft 45 of the reduction gear 5, a pinion 92, an output shaft 31, a gear 93 and an occupant 108. The exhaust passage 124 is formed on the left crank axle box 25L. The access passage 124 is formed by the guide rib 121, the clutch extension portion, the life 50, the step start wet separation 45, the stem housing for driving the upper wall 140, the foot View starter 100' wheel 102 mechanism 24 actuator horse. Figure 200949104 121 After the collision, the power unit cover 132 is turned to flow downward. The air 121 flows downwardly through the lower passage 135 formed between the left crank axle box 25L and the rear movable cover 132, and is discharged through the air outlet 136. Referring to FIG. 10, the cooling air 121 flows downward through the air guide rib output shaft protection. The rib 131 and the oil filler port 127 define a lower portion 135 and are discharged through the air outlet 136. The exhaust passage 135 of the exhaust passage 124 is protected by the rear power unit cover 132. Referring to Fig. 3, an oil filler port 127 is formed in the cavity between the generator 134 and the output shaft guard rib 131. The rear power unit covers the cavity except for the portion of the oil filler port 127. The continuation row 124 is formed below the oil filler port 127. The down passage 135 is formed in the cavity between the generator holding of the crankcase 25 and the output shaft guard rib 131. Therefore, the power unit does not bulge laterally. Since the oil filler port 127 is disposed in the cavity ® oil filler port 127 and the oil filter cap 133, it does not bulge laterally. Referring to Fig. 10, the oil filler port 127 is disposed in the cavity between the generator 134 and the kick starter shaft 47. Therefore, the oil refueling and the oil filter cover 133 do not bulge, so that the power unit 20 is formed. The above embodiment has the following effects. (1) Since the passage 124 for the belt-driven continuously variable transmission 23 extends in the upper portion of the crankcase 25, and the exhaust passage downstream passage 135 is formed on the opposite side of the exhaust passage 1 24 side The cooling unit is placed in the atmosphere 130, the passage passage is closed to the holding portion cover 132, the air passage is formed by the upper portion 134, and the machine holding portion 127 is tightened to the exhaust passage 124. The crank shaft-21 - 200949104 Box 25 On the side wall, therefore, dust and water can be effectively prevented from flowing through the exhaust passage 124 into the transmission case 63. (2) Since the exhaust passage 124 is formed integrally with the left crank axle housing 25L, the right crank axle housing 25R, and the inner transmission case 63A, the number of parts can be reduced. (3) Since the down passage 135 is formed in the cavity between the generator chamber 67 and the holding portion protection rib 131 of the output shaft 31 of the crankcase 25, as viewed from above, the power unit 20 does not bulge laterally. And can be formed tightly. ❹ (4) Since the oil filler port 127 is formed in the cavity close to the down passage 135, the components of the power unit 20 do not bulge laterally. (5) Since the down passage 135 is defined by the air guiding rib 130, the output shaft protecting rib 131 projecting laterally outward from the side wall of the left crank axle box 25L, and the power unit cover 132 covering the ribs, the 'downward passage 135 is received protection. (6) Since the rear power unit cover 132 covers both the descending passage 135 and the power output shaft 31 from the outside, the number of parts can be reduced. Ο (7) Since the peripheral wall 140 defining the exhaust passage 124 is also used as a reinforcing member for the reinforced power unit hanger projection 139, the power unit hanger projection 139 can be reinforced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of a motorcycle provided with a power unit according to a preferred embodiment of the present invention; Fig. 2 is a perspective view of a power unit from the right side of the motorcycle; -22- 200949104 Fig. 3 Fig. 2 is a development view of the section of the line I-III; Fig. 4 is a development view of the section of the line IV-IV in Fig. 2; Fig. 5 is viewed from the right side, on the outer wall of the outer gearbox Longitudinal sectional view of the outer gearbox taken from the plane between the deflectors; Figure 6 is a view from the left side, the left connecting surface of the gearbox and the interior of the transmission; Figure 7 is from the right side, the inner gearbox View of the right connecting surface and the drive © indoor; Figure 8 is the view of the right connecting surface of the right crankcase and the interior of the centrifugal clutch; Figure 9 is the right connecting surface of the left crankcase, the inside of the crankcase and the The view of the inside of the gear of the pedal starter mechanism; the first drawing is a side view of the left crank axle box from the left side; and the 11th drawing is a sectional view taken along line XI-XI of the first drawing. 〇[Main component symbol description] 23: Belt-driven continuous speed changer 24: Reduction gear mechanism 25: Crank axle box 25L: Left crank axle box 25R: Right crank axle box 4〇: Drive pulley 41: Drive pulley 42 : V-belt -23- 200949104 4 3 : Wet centrifugal clutch 62 : Generator cover 63 : Transmission box 63 A : Inner transmission box 63B : Outer transmission box 6 5 : Outer transmission box 66 : Crank shaft chamber 67 : Hair Motor chamber 7 1 : centrifugal clutch chamber 72 : baffle flap 73 : transmission chamber 74 : air guide chamber 95 : pedal starter gear chamber 1 1 5 : first air passage 1 16 : second air passage 1 1 7 : Hole in the driven shaft 1 2 1 : Cooling air 122 : Footrest 1 23 : Air inlet 124 : Exhaust passage 1 2 7 : Oil filler port 130 : Air guide rib 131 : Output shaft guard rib: Rear power unit cover -24 132 200949104
133 :機油濾清蓋 134 :發電機保持部 1 3 5 :下行通路 1 36 :空氣入口 -25-133: Oil filter cover 134: Generator holding part 1 3 5 : Downstream path 1 36 : Air inlet -25-