200406335 玖、發明說明： 【發明所屬之技術領域】 本發明是關於電動輔助自行車，更具體的是關於具有依 靠人力進行轉動操作而轉動驅動後輪的曲柄踏板、將作用 於這個曲柄踏板的踏力轉矩傳遞到前述後輪的轉動傳遞機 構和將輔助轉矩傳給這個轉動傳遞機構的輔助動力單元的 電動輔助自行車。 【先前技術】 在自行車上裝備輔助動力單元，將來自被人力蹬踏的曲 柄踏板的踏力轉矩和來自輔助動力單元的輔助轉矩的合力 作用於鏈條上，在這種電動輔助自行車上，為了將這個輔 助動力單元的轉動輸出作為輔助轉矩傳給鏈條，需要在掛 鏈條的部分加上來自輔助動力單元的轉動動力，就需要在 座支柱和在這個座支柱後方的後叉處支撐輔助動力單元。 由此，例如為了將輔助動力單元配置在後叉的下方，而使 用改變了形狀的車體框架，將這個後叉配置在比通常更加 上方的位置，而從座支柱向後延伸，用於搭載輔助動力單 元（例如，參照專利文獻 1 )和將輔助動力單元搭載於座 支柱後方的後叉上方處（例如，專利文獻2)等。 (專利文獻1 ) 日本專利特開2 0 0 0 — 0 0 2 6 0 4號公報（圖2 ) (專利文獻2 ) 曰本專利特開平1 1 — 1 0 5 7 7 4號公報（第3頁，圖1 ) 【發明内容】 6 312/發明說明書(補件)/92-12/92125190. 200406335 (發明所欲解決之問題） 但是，在使車體框架改變形狀的情況下，則存在需要準 備這種特別的支架而造成電動輔助自行車的成本提高的問 題，另外，在座支柱的後方而且是後叉的上方的位置配置 輔助動力單元的話，則有必須將電池箱和電裝品箱配置在 其他的位置上，而難於有效地利用車體的空間的問題。 本發明有鑒於這樣的問題，目的在於提供可以使用一般 的自行車支架，而且通過將輔助動力單元配置在後叉下 方，而可以有效地利用座支柱後方的空間，製造成本低的 電動輔助自行車。 (解決問題之手段） 為了達到這樣的目的，本發明的電動輔助自行車，具有 車體框架、可掌握方向地樞軸連接在該車體框架的前部的 車把架（例如實施形態中的前叉7以及轉向車把8 )、被自 由轉動地安裝在車把架下端的前輪、由與車體框架的後部 連成一體且向後方延伸的左右一對支撐構件組成的後叉、 位於該左右一對支撐構件之間且可自由轉動地安裝在後叉 上的後輪、被樞軸支撐並可自由轉動地安裝在車體框架上 的曲柄踏板、將踩踏該曲柄踏板而作用於該曲柄踏板上的 踏力轉矩傳遞到後輪上的轉動傳遞機構（例如，在實施形 態中由驅動鏈輪2 1、從動鏈輪2 3以及鏈條2 2構成的鏈條 機構）、輔助踏力轉矩並將輔助轉矩傳給轉動傳遞機構的輔 助動力單元，輔助動力單元具有電動機（例如，實施形態 中的電動馬達 1 5 )、將來自該電動機的轉動輸出進行減速 312/發明說明書(補件)/92-12/92125190. 200406335 的減速齒輪機構（例如，實施形態中的減速齒輪組 56)、 將被減速齒輪機構減速的轉動輸出作為輔助轉矩傳遞到轉 動傳遞機構的輔助動力傳遞部（例如，實施形態中的輔助 鏈輪 2 4 )、至少覆蓋了減速齒輪機構的收納構件（例如， 實施形態中的箱 5 0 )，在輔助動力單元配置在後叉的下方 的同時，收納構件具有覆蓋構成減速齒輪機構的大直徑齒 輪且向外部突出的突出部，突出部被配置在左右一對支撐 構件之間。 通過這樣的構成，可以將普通的車支架用於安裝輔助動 力單元的自行車支架，所以可以降低成本。另外，由於將 輔助動力單元配置在後又下方，所以可以在後叉上方有效 地利用座支柱後方的空間，可在那裏配置電池箱和電裝品 箱等。另外，由於可以將重量大的輔助動力單元配置在下 方，在可以降低重心穩定地行進的同時，由於有曲柄踏板 和鏈條、以及鏈罩等，可以使輔助動力單元不顯眼。 另外，較佳將收納構件的突出部的上部配置在從側面看 與後叉的上面幾乎相等的位置上，通過這樣的構成，可以 進一步降低電動輔助自行車的重心位置。 另外，減速齒輪機構具有與電動機的馬達軸平行地延伸 且被可以自由轉動地配置在收納構件上的第1轉動軸、形 成在該第1轉動軸上且與形成在馬達軸上的1次減速驅動 齒輪相嚙合的1次減速從動齒輪，在將電動機的馬達軸設 置於曲柄踏板附近的同時，較佳將馬達轴和第1轉動軸配 置成從側面看相對於地面呈近似水平地並列地配置，通過 8 312/發明說明書(補件)/92-12/92125190. 200406335 這樣的構成，可以在確保輔助動力單元的底面距離地 一定高度的同時，確保在第2轉動軸上形成的輔助動 遞部分上構成轉動傳遞機構的捲掛傳遞構件（例如， 形態中的鏈條2 2 )的捲繞角。 另外，減速齒輪機構具有與第1轉動軸平行地延伸 可以自由轉動地配置在收納構件上的第2轉動軸、形 該第2轉動軸上且與在第1轉動軸上形成的2次減速 齒輪相嚙合的2次減速從動齒輪，從側面看第2轉動 配置在第1轉動軸的上方是理想的，通過這樣的構成 以確保輔助動力單元的底面距離地面有一定高度。 【實施方式】 以下，參照附圖對本發明的較佳實施形態進行說明 先使用圖 1以及圖 2對本發明的電動輔助自行車進 明。圖2 ( A )是從左面看的本發明的電動輔助自行車 要部分，圖2 ( B )是在圖2 ( A )中將輔助動力單元 下的情況下的側視圖。但是，在圖2 ( B )中，圖示了 述的輔助鏈輪2 4和惰輪2 5以及支撐這個惰輪2 5的支 件8 3的一部分。 電動辅助自行車1具有車體框架2，這個車體框架 位於其前部而向上下方向延伸的車頭前管3和從車頭 3向後下方延伸的下降管4、被固定在下降管4的後端 左右延伸的支撐管5 (參照圖5 )、從支撐管5向上方 的座管6組成。在車頭前管3上，向下方延伸的前叉 可以自由轉向地支撐，前輪WF被軸支撐於這個前叉7 312/發明說明書(補件)/92-12/92125190. 面有 力傳 實施 且被 成在 驅動 軸被 ，可 〇首 行說 的主 .6拆 如後 撐構 2由 前管 而向 立起 7被 的下 9 200406335 端。另外，在前叉7的上端設置連成一體的轉向車把8， 操縱這個轉向車把8即可以操縱被軸支撐在這個前叉7上 的前輪WF。 從支撐管5向後方的一側上配置後叉9，該後叉9具有 與這個支撐管5形成一體而與地面平行那樣呈一直線地向 後方延伸的一對支撐構件9 L、9 R，後輪W R被作為驅動輪 軸支撐在這個左右一對的支撐構件9 L、9 R的後端部之間。 另外，左右一對的撐桿1 0被設置在座管6的上部和兩個支 撐構件9 L、9 R的後部之間。 上端具有車座1 1的座支柱1 2被可以調節車座1 1的上 下位置那樣地裝在座管6上。另外，在座管6的後端部可 以插上和脫開那樣地收納電池B的電池收納箱1 3、電裝品 箱1 4被向下排列地設置在座管6的後端部。然後，在後叉 9的下方，配置具有藉助電裝品箱1 4而由電池B供電的作 為輔助轉矩發生構件的電動馬達1 5的輔助動力單元1 6， 這個輔助動力單元1 6被支撐管5以及支撐構件9 L、9 R所 支撐。 在車體框架2的支撐管5上，同軸貫通這個支撐管5的 曲柄軸1 7被軸支撐，另外，具有被配置在這個曲柄軸1 7 的左端以及右端上而可以自由轉動的踏板的曲柄 1 8 L、1 8 R 被分別固定地連接，曲柄軸1 7、曲柄1 8 L、1 8 R以及被裝 在這個曲柄1 8 L、1 8 R上的踏板構成曲柄踏板。這樣，曲柄 1 8 L、1 8 R受到騎電動輔助自行車1的騎車人的踏力而可以 使曲柄軸1 7轉動，這個曲柄軸1 7被可以自由轉動地支撐 10 312/發明說明書(補件)/9孓12/92125190. 200406335 在車體框架2上。 在曲柄軸 1 7上，設置依靠後述的動力傳遞裝置傳遞 柄軸1 7的轉動的驅動鏈輪2 1，驅動鏈輪2 1的轉動通過 條2 2被傳遞到後輪W R側的從動鏈輪2 3上。在驅動鏈 21的後方，設置將來自輔助動力單元1 6的輔助轉矩傳 到鏈條2 2上的輔助鏈輪2 4。另外，在輔助鏈輪2 4的後：¾ 設置為了加大鏈條2 2相對於這個輔助鏈輪2 4的捲繞角 惰輪25。 另外，在本實施例中，採用了將踏力轉矩以及輔助轉 從驅動鏈輪2 1和輔助鏈輪2 4通過鏈條2 2傳遞到從動鏈 2 3上的鏈條機構，也可以使用皮帶機構將踏力轉矩以及 助轉矩傳遞到後輪WR上。 接下來，參照圖3以及圖4，對於被裝在曲柄軸1 7上 動力傳遞裝置進行說明。在被固定於下降管4上的支撐 5的兩端順螺紋插入蓋板1 9 L、1 9 R。在這個蓋板1 9 L、1 和曲柄軸 1 7上形成的段差之間分別嵌插滾珠軸承 2 0 L 2 0 R。即，滾珠軸承2 0 L、2 0 R承受加在曲柄軸1 7上的推 方向以及徑向的荷重而相對於支#管5可以自由轉動地 撐曲柄軸1 7。 在曲柄軸17上，固定第1單向離合器26的内輪27。 外，驅動鏈輪2 1通過軸襯2 7 A可以自由轉動地被支#在 個内輪2 7的外周。驅動鏈輪2 1的推力方向的位置被螺 2 8 A和板2 8 B所限制。 在驅動鏈輪2 1上整體地設置蓋體2 9，在被這些驅動 312/發明說明書(補件)/92-12/92125190. 曲 鏈 輪 遞 的 矩 輪 輔 的 管 9R 力 支 另 這 母 鏈 11 200406335 輪2 1和蓋體2 9所包圍的空間内，設置傳遞板3 0。這個傳 遞板3 0與驅動鏈輪2 1同軸，而且在以曲柄轴1 7為軸的轉 動方向上相互可以有預定量的偏移那樣被支撐。 驅動鏈輪2 1跨過傳遞板3 0，形成·多個（在此為6個） 窗3 1，在這個窗3 1的内側分別收容壓縮螺旋彈簧3 2。在 驅動鏈輪2 1以及傳遞板3 0之間相互地產生轉動方向的偏 移時，壓縮螺旋彈簧3 2產生相對於偏移的抗力那樣進行作 用。 在傳遞板3 0的襯套的内周形成作為第1單向離合器2 6 的外輪的棘輪齒3 3，這個棘輪齒3 3被内輪2 7所支#、與 依靠彈簧3 4向放射方向上加力的棘輪爪（在這裏有3個） 相結合，在這個第1單向離合器2 6上設置用於防塵的罩 36 〇 通過這樣的第1單向離合器2 6，踏曲柄1 8 L、1 8 R而使 曲柄軸1 7正轉時，通過彈簧3 4，棘輪爪3 5向棘輪齒3 3 壓靠，所以棘輪爪3 5與棘輪齒3 3的齒底部分相喃合而曲 柄1 8 L、1 8 R的踏力被傳遞到傳遞板3 0上，但是在踏曲柄 1 8 L、1 8 R而使曲柄轴1 7反轉或者在騎行中停止經踏時， 棘輪爪3 5在棘輪齒3 3的齒牙部分滑移而不嚙合，第1單 向離合器2 6滑移，所以曲柄軸1 7可以反轉，另外，來自 傳遞板3 0的轉矩不會傳遞到曲柄軸1 8 L、1 8 R上。 在傳遞板3 0上，設置後述的傳遞踏力用的突起部3 8所 結合的固定孔3 7。在驅動鏈輪2 1上，設置可以使突起部 3 8與固定孔3 7相結合的窗3 9，突起部3 8貫穿這個窗3 9 12 312/發明說明書(補件)/92-12/92125190. 200406335 與固定孔37相嵌合。 跨過驅動鏈輪2 1和傳遞板3 0，形成與前述窗3 1不同的 另夕卜多個（在此為3個）小窗4 0，在這個小窗4 0的内側 分別收容壓縮螺旋彈簧4 1。壓縮螺旋彈簧4 1是使傳遞板 3 0向轉動方向 4 2 —側壓靠配置的。即，作用於吸收驅動 鏈輪2 1以及傳遞板3 0結合部之間鬆動的方向，傳遞板3 0 的變位被以良好的應答性而傳遞到鏈輪 21上那樣進行作 用。 因此，曲柄 1 8 L、1 8 R 由於騎車人的證踏而加在曲柄轴 1 7上的踏力轉矩被通過第1單向離合器2 6傳遞到傳遞板 30 上，而這個踏力轉矩一邊壓縮各壓縮螺旋彈簧 32、41 一邊被傳遞到驅動鏈輪2 1上，再通過鏈條2 2以及從動鏈 輪2 3被傳遞到後輪W R上。並且，從後述的輔助動力單元 1 6給予輔助鏈輪2 4的輔助轉矩，通過鏈條2 2和從動鏈輪 2 3傳遞到後輪W R。另外，從該輔助動力單元1 6給予輔助 鏈輪2 4的輔助轉矩，通過第1單向離合器2 6的作用，不 會被傳遞到曲柄1 8 L、1 8 R上。 在驅動鏈輪2 1的靠車體側，即下降管 4側裝設踏力檢 測裝置的感測器部4 3。這個感測器部4 3具有固定在驅動 鏈輪2 1上的外側環4 4和可以相對於這個外側環4 4自由轉 動地設置用於形成磁電路的感測器本體4 5。對於感測器本 體4 5以及作為其支撐構件的套管4 6、法蘭盤4 7等，將在 後面敘述。 外側環 4 4是由具有電氣絕緣性能的材料形成的，由未 13 312/發明說明書(補件)/92-12/92125190. 200406335 被圖示的螺栓固定在驅動鏈輪2 1上。 接下來，用圖5〜圖9對輔助動力單元1 6進行說明。輔 助動力單元16的箱50由右半箱體51、在這個右半箱體51 之間形成第1收納室5 4且與右半箱體5 1相結合的左半箱 體5 2、在這個左半箱體5 2之間形成第2收納室5 5且與左 半箱體5 2相結合的罩5 3構成。 在箱5 0上，安裝具有與曲柄軸1 7的轉動軸線相平行的 軸線的電動馬達1 5。這個電動馬達1 5的轉動輸出應輔助 施加在曲柄18L、18R上的踏力轉矩，藉助輔助減速齒輪組 5 6傳遞到輔助鏈輪2 4上。 在箱50的左半箱體52上，一體地設置向與罩53相反 的一側突出的嵌合筒部7 4，具有電動馬達1 5的有底圓筒 形的馬達殼7 5，在被嵌合於嵌合筒部7 4上的狀態下，用 多個（例如3處）螺栓緊固在左半箱體5 2的螺孔7 6内。 另外，馬達軸57可以自由轉動地貫通支撐壁部77而向第 2收納室5 5突出，與支撐壁部7 7相接的馬達殼7 5和馬達 軸5 7之間裝滾珠軸承91。另外，馬達殼7 5例如是一體鑄 模形成的。 用於將電動馬達1 5的動力傳遞到輔助鏈輪2 4上的減速 齒輪組5 6的轉動軸是由具有與馬達軸5 7相平行轴線的第 1轉動軸5 9和具有與這個第1轉動軸5 9相平行軸線的第2 轉動軸6 4構成。在第1轉動軸5 9和左半箱體5 2之間裝滾 珠軸承6 9，在右半箱體51和第1轉動軸5 9之間裝滾珠軸 承7 0，第1轉動軸5 9被可以自由轉動地配置。另外，在 14 312/發明說明書(補件)/92-12/92125190. 200406335 左半箱體5 2和第2轉動軸6 4之間裝滾珠軸承7 1，在右半 箱體51和第2轉動軸6 4之間裝滾珠軸承7 2，第2轉動軸 64被可以自由轉動地配置 另外，具備在第2收納室5 5内被固定在電動馬達1 5的 馬達軸5 7上的1次減速驅動齒輪5 8、與在第2收納室5 5 内被螺栓6 0固定在第1轉動軸5 9上並與1次減速驅動齒 輪5 8相ϋ齒合的1次減速從動齒輪6 1、在第1收納室5 4内 與第1轉動軸5 9形成一體的2次減速驅動齒輪6 2，在第1 收納室5 4内被固定在第2轉動軸6 4上並與2次減速驅動 齒輪6 2相嚙合的2次減速從動齒輪6 3、被設在2次減速 從動齒輪6 3和第2轉動軸6 4之間的第2單向離合器6 5， 輔助鏈輪2 4被固定在從第2轉動軸6 4的右半箱體5 1向外 突出的部分上。另外，密封構件6 6被設在從右半箱體5 1 向第2轉動軸6 4突出的部分。另外，在1次減速從動齒輪 6 1的 2次減速驅動齒輪6 2 —側的面上，為了加強這個1 次減速從動齒輪6 1，用螺栓6 8緊固環形的增強板6 7。 另夕卜，在罩4 8的内側（第2收納室5 5側）形成多個肋 73，而可以提高這個罩48的剛性。另外，罩48是通過向 成型模内澆樹脂材料而形成的，而通過將罩48的内側形狀 作成上述那樣，可以改善在製造罩4 8時樹脂材料的流動。 在這樣的減速齒輪組5 6中，伴隨著電動馬達1 5動作的 轉動被減速後傳遞給輔助鏈輪2 4，在電動馬達1 5的動作 停止時和在驅動鏈輪2 1的轉動比輔助鏈輪2 4的轉動快的 情況下，由於第2單向離合器6 5的作用而允許第2轉動軸 15 312/發明說明書(補件)/92-12/92125190. 200406335 64空轉。而不會妨礙依靠來自曲柄18L、18R的踏力轉矩 而進行的輔助鏈輪2 4的轉動。 但是，輔助動力單元1 6被支撐管5以及支撐構件9 L、 9 R所支撐而被配置在後叉9的下方，在這時，馬達軸5 7 位於在比曲柄軸1 7略微後下方的曲柄踏板的附近，另外， 馬達軸5 7和第1轉動軸5 9從側面看是位於與地面略微平 行地那樣並列的。另外第2轉動軸64位於比第1轉動軸 5 9更上方的位置，形成使覆蓋被固定在這個第2轉動軸6 4 上的 2次減速從動齒輪 6 3的箱 5 0的部分突出的突出部 8 4，按照使這個突出部8 4在後輪W R的前方且可從下方插 入左右一對的支撐構件9 L、9 R之間那樣配置輔助動力單元 16° 這時，在固定於支撐管 5的托架 7 9上，用螺栓和螺母 緊固被向左半箱體 5 2的前方上部的上方隆起那樣設置的 懸掛部8 0，另外，在被緊固在左右一對的支撐構件9 L、9 R 上的托架8 1 L、8 1 R之間夾著被向後方上部的上方隆起那樣 設置的懸掛部8 2，其被螺栓和螺母緊固（將懸掛部分8 0、 8 2以及輔助動力單元1 6裝到電動輔助自行車1的狀態， 如圖2 ( A )所示。另外，箱5 0的突出部8 4的上部，從平 面圖的角度上看，是被配置在與後又9的上面幾乎相同的 位置上。 另外，在第2轉動軸6 4從右半箱體51突出的部分處， 形成向後方延伸的支撐構件8 3，惰輪2 5可以自由轉動那 樣地被軸支撐在這個支撐構件8 3的端部，右半箱體5 1和 16 312/發明說明書(補件)/92-12/92125190. 200406335 惰輪2 5形成一體。 如以上說明的那樣，使箱5 0的突出部8 4僅蓋住與2次 減速從動齒輪6 3相對的部分那樣而突出即可，所以呈在前 後方向細長延伸的形狀。這樣，即使用普通的自行車支架， 也可以從下方將這個突出部分插入構成後叉的左右一對的 支撐構件之間，而配置輔助動力裝置1 6，所以不需要準備 特殊的支架，從而可以降低製造成本。另外，通過將重量 大的輔助動力單元16配置在車體框架2的下部，可以降低 重心的位置，而提高行進時的穩定性。另外，由於不在後 叉9的上方而且是座管12的後方空間内配置輔助動力單元 1 6，可以有效地利用這個空間，如在本實施例中說明的那 樣，可以配置電池收納箱1 3和電裝品箱1 4等。 另外，由於輔助動力單元 16的配置位置是在驅動鏈輪 2 1 和被掛在那個驅動鏈輪2 1上的鏈條2 2的附近，故可使 這個輔助動力單元16的存在不顯眼，特別是用鏈罩蓋上的 話，可以更加不顯眼。 另外，通過將馬達軸5 7和第1轉動軸5 9與地面平行地 那樣並列配置，還將第2轉動軸6 4配置在第1轉動軸5 9 的上方，可以確保輔助動力單元16的底面距離地面一定的 高度，另外，可以在一定程度上確保鏈條2 2相對於被固定 在第2轉動軸64上的輔助鏈輪24的捲繞角。 下面，通過圖10〜13說明構成該輔助動力單元16的電 動馬達1 5。電動馬達1 5是通過直流電源驅動的直流無刷 馬達’具有馬達軸57、包圍馬達軸57地配置的定子85、 17 312/發明說明書(補件)/92-12/92125190. 200406335 固定在馬達軸5 7上的轉子8 6以及檢測該轉子位置的轉子 位置檢測器8 7，整體被馬達殼7 5所覆蓋。 定子85是通過在定子磁芯88上繞定子線圈89而構成， 而被沿著馬達殼7 5的内周面設置多個（在此為9個）。另 外，轉子8 6與上述定子8 5相對那樣配置多個（在此為8 個）永久磁鐵9 0，按照N極、S極交替那樣排列與這個永 久磁鐵9 0的定子8 5相對的磁極。這時在定子8 5和轉子 86之間形成一定間隔的空隙。 另外，在馬達轴5 7和馬達殼7 5之間裝滾珠軸承9 1、9 2 而軸支撐這個馬達軸5 7。另外，在馬達殼7 5的側面且為 在馬達軸5 7突出的一側上，形成多個（在此為3個）托架 9 3，螺栓穿過這個托架9 3的貫通孔而將電動馬達1 5固定 在箱 5 0上。另外，轉子位置檢測器8 7被按照與轉子8 6 的上面平行和留有所確定的空隙那樣配置，用這個轉子位 置檢測器8 7具有的霍爾元件，檢測出移動到轉子位置檢測 器87下方的轉子86的N極。 被繞在定子磁芯8 8上的定子線圈8 9，按圖1 3所示順序 進行電氣連接，具有3相（U、V、W相）輸入端子94。加 在這個輸入端子9 4上的電壓被電裝品箱1 4所具有的控制 裝置所控制而從電池B提供，在輸入端子9 4上加一個相位 各相差120度的脈衝電壓的話，多個定子85的磁極N極、 S極交替出現，而且，定子8 5的磁極對應於這個脈衝的頻 率而移動，這樣，通過電裝品箱1 4而得到用轉子位置檢測 器8 7檢測到的轉子8 6的永久磁鐵9 0的位置，通過根據這 18 312/發明說明書(補件)/92-12/92125190. 200406335 個永久磁鐵9 0的位置而調整加在定子8 5上脈衝電壓， 以使馬達軸 5 7轉動。另外，通過控制加在這個輸入端 9 4上的脈衝電壓的脈衝波幅的P W Μ控制，可以控制轉子 的轉動速度（電動機的輸出）。 另外，由於這個轉子位置檢測器 8 7檢測出向這個轉 位置檢測器8 7的下方移動的永久磁鐵9 0的Ν極，通過 這個次數，可以從這個Ν極的檢測信號的次數計算出馬 軸5 7的轉數（轉速）。 在以上那樣構成的電動輔助自行車1上，依靠人力， 驅動方向（正轉方向）踏曲柄1 8 L、1 8 R，被固定在曲柄 1 7上的内輪2 7轉動，那個轉動被通過棘輪爪3 5傳遞到 輪齒。然後，使傳遞板3 0轉動，這個轉動被通過壓縮螺 彈簧3 2傳遞到驅動鏈輪2 1上，而由於在驅動鏈輪2 1上 了轉矩，所以傳遞板3 0的轉矩不會被立即傳遞到驅動鏈 2 1上，首先，由於轉矩壓縮螺旋彈簧3 2發生撓變，在 個撓變負荷與轉矩平衡時，驅動鏈輪2 1轉動。這樣，傳 板3 0以及驅動鏈輪2 1以具有與轉矩相對應方向的偏移 狀態進行轉動，通過鏈條2 2給後輪W R以驅動力。加在 動鏈輪2 1上的轉矩被作為騎車人蹬踏曲柄1 8 L、1 8 R的 力，即踏力轉矩而被檢測出。 由於從踏力檢測裝置的感測器本體4 3突出的突起部 與傳遞板3 0同時轉動，所以支撐這個突起部3 8的踏力 遞環9 5 (以下，與外側環4 4相對應，而將踏力傳遞環 稱為内側環9 5 )和被固定在驅動鏈輪2 1上的外側環4 4 312/發明說明書(補件)/92-12/92125190. 可 子 86 子 數 達 向 軸 棘 旋 加 輪 這 遞 的 驅 踏 38 傳 95 的 19 200406335 相對位置與轉矩相對應而被決定。這個相對位置被感測器 本體4 3檢測到，而提供給檢測踏力的控制裝置（在後面 述）。 使用圖1 4及圖1 5詳細說明這個感測器本體4 3。用具有 電氣絕緣性能的材料形成外側環4 4，設置3處螺栓孔9 6， 而可以將用於使這個外側環4 4固定在驅動鏈輪2 1上的螺 栓貫通。沿外側環4 4的内周面配置第1感應體9 7 A，還配 置與第1感應體9 7 A相鄰的第2感應體9 7 B。另外，在第2 感應體9 7 B上沿外周面配置内側環9 5。第1感應體9 7 A和 第2感應體9 7 B由鋁和黃銅等的高導電率材料或軟磁材料 構成，如後述的那樣，分別被固定在外側環44以及内側環 9 5上。 夾著第1感應體97A和第2感應體97B設置兩片1組的 環狀磁芯板9 8、9 9，而且在這些磁芯板9 8、9 9的内周側 設置磁芯軸環1 0 0。磁芯板9 8、9 9以及磁芯軸環1 0 0由軟 鐵氧化物等的軟磁材料組成。線圈1 0 1被繞在磁芯軸環1 0 0 的外周，通過磁芯板9 8、9 9以及磁芯軸環1 0 0，還有第1 感應體97A和第2感應體97B，在向線圈101通電時產生 的磁通貫通，形成磁電路。磁芯板 9 8、9 9以及磁芯軸環 1 0 0，被套管4 6以及具有與這個套管4 6的内紋螺紋相配外 紋螺紋的法蘭盤4 7所支撐。另外，套管4 6以及法蘭盤4 7 被支撐管5所支撐，而限制轉動。 向前述線圈1 0 1供應電流的引出線1 0 4，貫穿套管4 6並 向外部引出，與後述的控制裝置1 1 0相連接。在外側環4 4 20 312/發明說明書(補件)/92-12/92125190. 200406335 和套管4 6之間設置油封1 0 5，在外側環4 4和内側環9 5之 間以及内側環9 5和法蘭盤4 7之間，分別設置密封件1 0 6、 1 0 7。按照可以與固定孔3 7相配合那樣，從設在罩4 8上的 開口 4 8 Α向外部突出那樣設置從内側環9 5向直角突出的突 起部38。 圖16是第1感應體97A的前視圖，圖17是剖面圖。第 1感應體97A整體為環形，在其内周上形成多個齒108。在 第2感應體97B上也設置與這些齒108相同的齒。通過這 些齒的重疊，形成由線圈1 0 1而產生的磁通的通路的一部 分。在齒1 0 8的兩個地方，形成從罩形的第1感應體9 7 A 的底部向外突出的突起部1 0 9 A。按照第1感應體9 7 A可以 與外側環4 4 一體地轉動那樣，與在外側環4 4上形成的凹 部嵌合那樣設定突起部1 0 9 A。 圖1 8是第2感應體9 7 B的剖面圖。第2感應體9 7 B與 第1感應體9 7 A形狀相同。但是，外周要比第1感應體9 7 A 小一圈。另外，如圖1 8所示的那樣，第2感應體9 7 B具有 從帽形的第2感應體9 7 B的底部向外打出的突起部1 0 9 B。 按照在與第2感應體9 7 B相接的内側環9 5上形成的凹部嵌 合那樣設定這個突起部1 0 9 B。 圖1 9是表示由線圈1 0 1產生的磁通貫通的磁電路的模 式圖，在這個圖中，在線圈1 0 1通電時產生的磁通Φ形成 包括磁芯板9 8、9 9以及磁芯軸環1 0 0，還有第1感應體9 7 A '和第2感應體9 7 B的磁電路。這時，磁通Φ的指向，例如 在圖1 9中表示的那樣。在此，線圈1 0 1的阻抗被用磁通Φ 21 312/發明說明書(補件)/92-12/92125190. 200406335 通過的電路的阻抗，即磁電路阻抗的函數表示。另外，磁 通Φ實質地通過設在第1感應體97A以及第2感應體97B 的内周上的齒（在第1感應體9 7 A上的齒1 0 8 )，所以這個 部分的磁電路的阻抗由第1感應體9 7 A以及第2感應體9 7 B 的各個齒的重疊量所決定。 如上述那樣，外側環4 4和内側環9 5相應於踏力轉矩相 互產生偏移，第1感應體9 7 A以及第2感應體9 7 B的相對 位置上也隨之產生偏移。其結果是第1感應體9 7 A以及第 2感應體9 7 B的各個齒的重疊程度也相應於踏力轉矩而變 化。 圖2 0是表示根據踏力轉矩的不同第1感應體9 7 A以及 第2感應體97B所具有的各自的齒的重疊程度不同的圖。 從這些圖可知，在踏力轉矩小的情況下，第1感應體97 A 以及第2感應體9 7 B的重疊程度變大，所以用第1感應體 9 7 A以及第2感應體9 7 B的齒將通過磁芯板9 8、9 9之間的 磁通遮擋的比例減小，所以磁電路阻抗變小。另外，在踏 力轉矩大的情況下，第1感應體9 7 A以及第2感應體9 7 B 的重疊程度變小，所以用第1感應體97A以及第2感應體 9 7 B 的齒將通過磁芯板 9 8、9 9之間的磁通遮擋的比例增 加，所以磁電路阻抗變大。 這樣，磁通所通過通路的阻抗對應於踏力轉矩而改變， 所以通過檢測作為這個磁電路阻抗函數的線圈 1 0 1的阻 抗，可以檢測踏力轉矩。 如圖 2 1所示，根據線圈1 01的阻抗，檢測踏力阻抗的 22 312/發明說明書(補件)/92-12/92125190. 200406335 控制裝置1 1 0的振盪電路1 1 1、峰值保持電路1 1 2、以及阻 抗 1 1 3與線圈1 0 1 —起構成這個控制裝置1 1 0的主要部 分。峰值保持電路 1 1 2的輸出由C P U 1 1 4處理。振盪電路 1 1 1輸出預定頻率的交流電（在圖2 2 ( A )中表示圖2 1的 點a的波形）。第1感應體9 7 A以及第2感應體9 7 B的各個 齒的重疊程度大的情況下，在線圈1 0 1中產生的磁通Φ的 磁電路阻抗大，所以在點 b的波形的振幅變大（在圖 21 的點b伴隨著踏力增加的波形在圖2 2 ( B )中表示）。點b 的振幅被峰值保持電路1 1 2所保持，其峰值保持值，即點 b的值（參照圖2 2 ( C ))被作為踏力轉矩輸入到C P U 1 1 4。 構成輔助動力單元1 6的電動馬達1 5被作為負荷連接在 控制裝置1 1 0上，作為電源連接有電池B。 電動馬達 1 5的驅動電路由 F E T 1 1 7、二極體 1 1 8、電容 1 1 9所構成。電池B的正電極被通過接點1 2 0接到電動馬 達1 5的正端子上，電池B的負電極被通過F E T 1 1 7接到電 動馬達1 5的負端子上。 接點1 2 0按照C P U 1 1 4的指令，根據線圈1 2 1的通電而 進行 Ο N動作。被供到電動馬達1 5上的電流由從 C P U 1 1 4 加到F E T 1 1 7的閘極上的電壓所決定。C P U 1 1 4參照對應於 踏力值的踏力轉矩值/電壓表，或者根據預定的計算式進行 計算，而求得與踏力轉矩值對應的電壓值，將這個電壓加 到F E T 1 1 7的閘極上。按照被輸入到C P U 1 1 4的踏力轉矩的 值增大的同時，電動馬達1 5的輸出增大那樣設定踏力轉矩 值/電壓表或者計算式是理想的。 23 312/發明說明書(補件)/92-12/92125190. 200406335 根據本實施形態，例如產生了組裝精度上的偏差而在第 1感應體9 7 A以及第2感應體9 7 B之間，磁芯板9 8、9 9的 位置在軸向偏移，第1感應體9 7 A以及磁芯板9 8之間的距 離變窄時，第2感應體9 7 B以及磁芯板9 9之間的距離增 大。與此相反，第1感應體9 7 A以及磁芯板9 8之間的距離 增大時，第2感應體9 7 B以及磁芯板9 9之間的距離縮小。 這樣，一方的間隔變化被另一方的間隔變化所抵銷，作為 整體的磁電路阻抗可以維持一定。 另外，在第1感應體97A以及第2感應體97B之間，磁 芯板 9 8、9 9 的位置在半徑方向偏移，在半徑方向的一方 上，第1感應體9 7 A以及第2感應體9 7 B和磁芯板9 8、9 9 的重疊加大時，在半徑方向的另一方上，第1感應體97A 以及第2感應體9 7 B和磁芯板9 8、9 9的重疊變小。因此， 一方磁電路阻抗增大，而在另一方磁電路阻抗減小，結果 是作為整體的磁電路阻抗可以維持一定。 另外，本發明的電動輔助自行車 1，設置限制器，當這 個電動輔助自行車1以超過所規定的速度行進時，不管來 自踏力檢測裝置的輸出如何而使輔助單元停止，不發生輔 助轉矩那樣進行控制，為了檢測出電動輔助自行車1的行 進速度，使用上述電動馬達1 5的轉子位置檢測器8 7檢測 的N極的檢測信號。被固定在電動馬達1 5的轉子8 6上的 永久磁鐵9 0的N極的個數由電動機所決定（在此為4極）， 通過計數從轉子位置檢測器8 7輸出的N極的檢測信號，可 以得到電動馬達1 5的轉數（轉速）。 24 312/發明說明書(補件)/92-12/92125190. 200406335 騎車人踏曲柄 1 8 L、1 8 R而加踏力轉矩時，如上述，電 動馬達1 5被控制電路11 0所驅動，從輔助動力單元1 6的 輔助鏈輪2 4向鏈條2 2加輔助轉矩。這時，由於連接著構 成這個輔助動力單元16的第2單向離合器65，電動馬達 15的馬達軸57的轉動和輔助鏈輪24的轉動與減速齒輪組 5 6的齒輪比成比例。這樣，可以從電動馬達1 5的馬達轴 5 7的轉數求得電動輔助自行車1的車速。 另外，騎車人的踏力轉矩加在曲柄 18L、18R上，如車 速增加而超過所規定的速度，則輔助動力單元1 6的電動馬 達15停止而不加輔助轉矩，但是，由於第2單向離合器 6 5滑動，不會從鏈條2 2向輔助動力單元1 6加轉矩，辅助 動力單元16不會妨礙曲柄18L、18R引起的曲柄踏板的轉 動。 對於根據車速控制輔助轉矩的限制器，向上述控制裝置 1 1 0傳遞電動馬達1 5的轉子位置檢測器8 7的輸出，可以 在用CPU114計算車速的同時，實現電動馬達15的控制。 另外，在圖21中，表示了控制裝置110控制具有現有的整 流元件的直流馬達的情況，而對於上述那樣的無刷直流馬 達，為了控制直流馬達，而從電池B的輸出生成三相脈衝 電壓並加在電動馬達1 5上而進行對應。 (發明效果） 由以上的說明可知，根據本發明的電動輔助自行車，在 將輔助動力單元配置在後叉的下方的同時通過將覆蓋構成 這個動力單元的減速齒輪機構的大徑齒輪的收納構件的突 25 312/發明說明書(補件)/92-12/92125190. 200406335 出部分從下方插入左右一對的支撐構件之間，可以用 的自行車支架作為裝這個動力單元的自行車的支架， 可以降低製造成本。另外，由於將輔助動力裝置配置 叉的下方，所以可以有效地利用後叉上方而且是座管 的空間，可以配置電池箱和電裝品箱等。另夕卜，由於 量大的輔助動力單元配置在下方，可以降低重心的位 穩定地行進的同時由於曲柄踏板和鏈條，再有鏈罩等 使輔助動力單元不顯眼。 另夕卜，從側面看通過將收納構件的突出部分的上部 在為與後叉的上面幾乎相等的位置上，通過這樣的構 可以進一步降低電動輔助自行車的重心位置，而穩定 進。 另外，具有輔助動力單元的電動機的馬達軸被配置 板近旁的同時，從側面看具有輔助動力單元的減速齒 構的第1轉動軸和電動機的馬達軸的位置相對於地面 似水平地並列配置，通過這樣的構成，可以在確保輔 力單元的底面距離地面有一定高度，而且可以確保掛 助動力單元的輔助動力傳遞部分上的捲掛傳遞構件的 角。 另外，上述減速齒輪機構具有第2轉動軸、從側面 2轉動軸被配置在第1轉動軸的上方，通過這樣的構 可以確保輔助動力單元的底面距離地面有一定高度。 【圖式簡單說明】 圖1為本發明的電動輔助自行車的側視圖。 312/發明說明書(補件)/92-12/92125190. 普通 從而 在後 後方 將重 置， 可以 配置 成， 地行 在踏 輪機 呈近 助動 在輔 捲繞 看第 成， 26 200406335 圖2為本發明的電動輔助自行車的主要部分的放大圖， 圖2 ( A )是裝了輔助單元的情況下的側視圖，圖2 ( B )是 將輔助單元拆下的情況下的側視圖。 圖3為本發明的電動輔助自行車曲柄軸以及驅動鏈輪附 近的剖面圖。 圖4為圖3沿I V — I V線之剖面圖。 圖5為圖2 ( A )沿V — V線之剖面圖。 圖6為圖2 ( A )沿V I — V I線之剖面圖。 圖7為圖2 ( A )沿V I I — V I I線之剖面圖。 圖8為左罩半體的側視圖。 圖9為右罩半體的側視圖。 圖1 0為電動馬達的剖面圖。 圖1 1為圖1 0沿X I — X I線之剖面圖。 圖1 2為圖1 0沿X I I — X I I線之剖面圖。 圖1 3為電動馬達定子線圈的配線圖。 圖 1 4為踏力檢測裝置的感測器部分的主要部分的剖面 圖。 圖1 5為踏力檢測裝置的感測器部分的前視圖。 圖16為第1感應體的前視圖。 圖17為第2感應體的剖面圖。 圖18為第2感應體的剖面圖。 圖 19為表示由線圈產生的磁通所貫通的磁電路的模式 圖。 圖20為表示第1感應體和第2感應體重疊程度的圖， 27 312/發明說明書(補件)/92-12/92125190. 200406335 圖2 0 ( A )為踏力轉矩小時的圖，圖2 0 ( B )為踏力轉矩大 時的圖。 圖2 1是控制裝置的踏力檢測電路。 圖2 2為表示線圈的電壓和踏力關係的圖，圖2 2 ( A )是 在圖21的a點的波形圖，圖2 2 ( B )是在圖21的b點的 波形，圖2 2 ( C )是表示在圖2 1的c點的線圈電壓與踏力 關係的圖。 (元件符號說明） 1 電 動 輔 助 自行車 2 車 體 框 架 3 車 頭 前 管 4 下 降 管 5 支 撐 管 6 座 管 7 前 叉 8 轉 向 車 把 9 後 叉 9L、9R 支 撐 構 件 10 撐 桿 11 車 座 12 座 支 柱 13 電 池 收 納 箱 14 電 裝 品 箱 15 電 動 馬 達 (電動機） 312/發明說明書(補件)/92-12/92125190. 28 200406335 16 輔 助 動 力 單 元 17 曲 柄 轴 1 8L、 1 8R 曲 柄 1 9L、 1 9R 蓋 板 20L、 20R 滾 球 軸 承 2 1 驅 動 鏈 輪 22 鏈 條 23 從 動 鍵 輪 24 輔 助 鏈 輪 25 惰 輪 26 第 1 單 向 離 合器 27 内 輪 27 A 轴 襯 28 A 螺 母 28B 板 29 蓋 體 30 傳 遞 板 3 1 窗 32 壓 縮 螺 旋 彈 簧 33 棘 輪 齒 34 彈 簧 35 棘 輪 爪 36 罩 37 固 定 孔 312/發明說明書(補件)/92-12/92125190.200406335 发明 Description of the invention: [Technical field to which the invention belongs] The present invention relates to electric assisted bicycles, and more specifically, to a crank pedal having a rear wheel that is driven by a human to perform a rotational operation, and the pedaling force acting on the crank pedal The torque is transmitted to the aforementioned rotation transmission mechanism of the rear wheel and an electric assist bicycle that transmits an assist torque to an auxiliary power unit of this rotation transmission mechanism. [Prior art] Equipped with an auxiliary power unit on a bicycle, the combined force of the pedaling torque from the crank pedal pedaled by the human and the auxiliary torque from the auxiliary power unit is applied to the chain. The rotation output of this auxiliary power unit is transmitted to the chain as auxiliary torque. The rotation power from the auxiliary power unit needs to be added to the part of the chain, and the auxiliary power unit needs to be supported at the seat post and the rear fork behind the seat post. . Therefore, for example, in order to dispose the auxiliary power unit under the rear fork, a shape-changing body frame is used, the rear fork is disposed at a position higher than usual, and is extended rearwardly from the seat pillar for carrying the auxiliary A power unit (for example, refer to Patent Document 1), an auxiliary power unit is mounted above a rear fork behind a seat post (for example, Patent Document 2), and the like. (Patent Document 1) Japanese Patent Laid-Open No. 2 0 0 — 0 0 2 6 0 4 (Figure 2) (Patent Document 2) Japanese Patent Laid-Open No. 1 1 — 1 0 5 7 7 4 (No. 3 Page, Figure 1) [Summary of the Invention] 6 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 (Problems to be Solved by the Invention) However, when the shape of the vehicle body frame is changed, there is a problem that such a special bracket needs to be prepared to increase the cost of the electric assist bicycle. In addition, the rear of the seat pillar is also If the auxiliary power unit is disposed above the rear fork, there is a problem that the battery box and the electric component box must be disposed at other positions, and it is difficult to effectively use the space of the vehicle body. The present invention has been made in view of such a problem, and an object thereof is to provide an electric assist bicycle which can use a general bicycle stand, and can effectively use the space behind the seat post by arranging the auxiliary power unit under the rear fork, thereby making the manufacturing cost low. (Means for Solving the Problem) In order to achieve such an object, the electric assist bicycle of the present invention has a body frame and a handlebar frame that is pivotally connected to the front portion of the body frame (eg, the front of the embodiment). The fork 7 and the steering handlebar 8), a front wheel that is freely rotatably mounted on the lower end of the handlebar frame, a rear fork composed of a pair of left and right support members integrated with the rear portion of the body frame and extending rearward, A rear wheel rotatably mounted on the rear fork between a pair of support members, a crank pedal supported by the pivot and rotatably mounted on the body frame, and the crank pedal will be stepped on to act on the crank pedal The pedaling torque on the rear wheel is transmitted to the rotation transmitting mechanism on the rear wheel (for example, in the embodiment, a chain mechanism composed of the driving sprocket 21, the driven sprocket 23, and the chain 22), the auxiliary pedaling torque and The auxiliary torque is transmitted to the auxiliary power unit of the rotation transmission mechanism. The auxiliary power unit includes a motor (for example, the electric motor 15 in the embodiment), and outputs the rotation from the motor. Deceleration 312 / present specification (complement member) / 92-12 / 92125190. The reduction gear mechanism of 200406335 (for example, the reduction gear set 56 in the embodiment), and the auxiliary power transmission section (for example, the auxiliary chain in the embodiment) that transmits the rotation output decelerated by the reduction gear mechanism as an auxiliary torque Wheels 2 4), a storage member covering at least the reduction gear mechanism (for example, a box 50 in the embodiment), the storage member has a large diameter covering the reduction gear mechanism while the auxiliary power unit is disposed below the rear fork. A protruding portion of the gear that protrudes outward, and the protruding portion is disposed between the pair of left and right support members. With such a configuration, a general vehicle bracket can be used for a bicycle bracket to which an auxiliary power unit is mounted, so that cost can be reduced. In addition, since the auxiliary power unit is arranged at the rear and the lower side, the space behind the seat post can be effectively used above the rear fork, and a battery box and an electric box can be arranged there. In addition, since the auxiliary power unit having a large weight can be arranged below, the center of gravity can be stably lowered, and the auxiliary power unit can be made inconspicuous due to the presence of a crank pedal, a chain, and a chain cover. In addition, it is preferable that the upper portion of the protruding portion of the storage member is arranged at a position almost equal to the upper surface of the rear fork when viewed from the side. With this configuration, the position of the center of gravity of the electric assist bicycle can be further reduced. In addition, the reduction gear mechanism includes a first rotation shaft extending parallel to the motor shaft of the motor and rotatably disposed on the storage member, and a first speed reduction formed on the first rotation shaft and the motor shaft. The primary deceleration driven gear that meshes with the driving gear is preferably provided with the motor shaft of the motor near the crank pedal, and the motor shaft and the first rotation shaft are preferably arranged side by side approximately horizontally with respect to the ground when viewed from the side. Configuration through 8 312 / Invention Specification (Supplement) / 92-12 / 92125190. The structure of 200406335 can ensure a certain height of the bottom surface of the auxiliary power unit, and at the same time ensure a roll transmission member (for example, a chain in the form) constituting a rotation transmission mechanism on the auxiliary movement portion formed on the second rotation shaft. 2 2) Winding angle. In addition, the reduction gear mechanism includes a second rotation shaft extending parallel to the first rotation shaft and rotatably disposed on the storage member, and a second reduction gear formed on the second rotation shaft and formed on the first rotation shaft. The meshed secondary deceleration driven gears are ideal when the second rotation is arranged above the first rotation shaft when viewed from the side. This configuration ensures that the bottom surface of the auxiliary power unit has a certain height from the ground. [Embodiment] Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. First, an electric assist bicycle of the present invention will be described using FIG. 1 and FIG. 2. Fig. 2 (A) is a main part of the electric assist bicycle of the present invention viewed from the left side, and Fig. 2 (B) is a side view of the case where the auxiliary power unit is lowered in Fig. 2 (A). However, in FIG. 2 (B), the auxiliary sprocket 24 and the idler 25, as well as a part of the support member 83 supporting this idler 25, are illustrated. The electric-assisted bicycle 1 includes a vehicle body frame 2. The vehicle body frame is located at the front of the vehicle. The extended support tube 5 (see FIG. 5) and a seat tube 6 extending upward from the support tube 5 are composed. On the front tube 3, the front fork extending downward can be freely steered, and the front wheel WF is axially supported by the front fork 7 312 / Invention Specification (Supplement) / 92-12 / 92125190. The force transmission is implemented on the surface and it is made on the driving shaft. 6 Remove the rear support structure 2 from the front tube to stand 7 to the bottom 9 200406335 end. In addition, an integrated steering handlebar 8 is provided at the upper end of the front fork 7, and the steering wheel handle 8 can be operated to operate the front wheels WF supported by the front fork 7. A rear fork 9 is disposed on the rear side from the support pipe 5. The rear fork 9 has a pair of support members 9 L, 9 R which are integrated with this support pipe 5 and extend rearward in a straight line so as to be parallel to the ground. The wheel WR is supported as a driving wheel shaft between the rear end portions of the pair of left and right support members 9 L, 9 R. A pair of left and right stays 10 are provided between the upper part of the seat tube 6 and the rear parts of the two support members 9L and 9R. A seat post 12 having a seat 11 at the upper end is mounted on the seat tube 6 in such a manner that the upper and lower positions of the seat 11 can be adjusted. In addition, a battery storage box 1 3, in which the battery B is accommodated at the rear end portion of the seat tube 6 so as to be inserted and detached, is provided at the rear end portion of the seat tube 6 so as to be aligned downward. Then, an auxiliary power unit 16 having an electric motor 15 as an auxiliary torque generating member powered by the battery B via the electric component box 14 is disposed below the rear fork 9, and the auxiliary power unit 16 is supported. The tube 5 and the supporting members 9 L and 9 R are supported. On the support tube 5 of the vehicle body frame 2, a crank shaft 17 coaxially penetrating through the support tube 5 is supported by the shaft, and a crank having a pedal that is rotatably disposed on the left end and the right end of the crank shaft 17 is supported. 1 8 L, 1 8 R are fixedly connected, respectively. The crank shaft 17, the cranks 1 8 L, 1 8 R, and the pedals mounted on the cranks 1 8 L, 1 8 R constitute a crank pedal. In this way, the cranks 1 8 L, 1 8 R can be rotated by the pedaling force of the rider riding the electric assist bicycle 1, and this crank shaft 17 is rotatably supported 10 312 / Invention Manual (Supplementary Documents) ) / 9 孓 12/92125190. 200406335 on the body frame 2. The crank shaft 17 is provided with a drive sprocket 21 that transmits rotation of the crank shaft 17 by a power transmission device described later, and the rotation of the drive sprocket 21 is transmitted to the driven chain on the rear wheel WR side through the bar 2 2 Round 2 3 up. Behind the drive chain 21, an auxiliary sprocket 24 is provided to transmit the auxiliary torque from the auxiliary power unit 16 to the chain 22. In addition, behind the auxiliary sprocket 24, an idler 25 is provided to increase the winding angle of the chain 22 with respect to this auxiliary sprocket 24. In addition, in this embodiment, a chain mechanism that transmits pedaling torque and auxiliary rotation from the driving sprocket 21 and the auxiliary sprocket 24 to the driven chain 23 through the chain 22 is adopted, and a belt mechanism may also be used. The pedaling torque and assist torque are transmitted to the rear wheel WR. Next, a power transmission device mounted on the crank shaft 17 will be described with reference to Figs. 3 and 4. The cover plates 19 L, 19 R are threadedly inserted into both ends of the support 5 fixed to the downcomer 4. Ball bearings 20 L 2 0 R are inserted between the cover plates 19 L, 1 and the step formed on the crank shaft 17 respectively. In other words, the ball bearings 20 L and 20 R support the crank shaft 17 in a thrust direction and a radial load applied to the crank shaft 17 and can freely rotate relative to the support tube 5. An inner wheel 27 of the first one-way clutch 26 is fixed to the crank shaft 17. In addition, the driving sprocket 21 is rotatably supported on the outer periphery of the inner wheels 2 7 through a bush 2 7 A. The position in the thrust direction of the driving sprocket 21 is restricted by the screw 2 8 A and the plate 2 8 B. A cover body 29 is integrally provided on the driving sprocket 21, and is driven by these 312 / Invention Specification (Supplement) / 92-12 / 92125190. The curved tube sprocket passes the auxiliary tube 9R to support the mother chain 11 200406335. In the space enclosed by the wheel 2 1 and the cover 2 9, a transfer plate 30 is provided. This transmission plate 30 is coaxial with the drive sprocket 21, and is supported so as to be offset from each other by a predetermined amount in the direction of rotation with the crank shaft 17 as the axis. The drive sprocket 21 crosses the transmission plate 30 to form a plurality of (six in this case) windows 31, and the compression coil springs 32 are housed inside the windows 31, respectively. When the driving sprocket 21 and the transmission plate 30 are shifted in the rotation direction with respect to each other, the compression coil spring 32 acts as a resistance against the displacement. A ratchet tooth 3 3 is formed on the inner periphery of the bushing of the transmission plate 30 as an outer wheel of the first one-way clutch 2 6. This ratchet tooth 3 3 is supported by the inner wheel 2 7 and is radiated in the radial direction by the spring 34. A combination of booster ratchet claws (three in this case) is provided on this first one-way clutch 2 6 for a dustproof cover 36 〇 Through such a first one-way clutch 26, the crank 18 8 L, When the crank shaft 1 7 is rotated forward by 1 8 R, the ratchet claw 3 5 is pressed against the ratchet teeth 3 3 by the spring 3 4, so the ratchet claw 3 5 and the bottom portion of the ratchet teeth 3 3 are fused to form the crank 1 The pedaling force of 8 L, 1 8 R is transmitted to the transmission plate 3 0, but when the crank shaft 1 8 L, 1 8 R is depressed to reverse the crank shaft 17 or the pedaling is stopped during riding, the ratchet claws 3 5 at The teeth of the ratchet teeth 3 3 slip and not mesh, and the first one-way clutch 2 6 slips, so the crank shaft 17 can be reversed. In addition, the torque from the transmission plate 30 is not transmitted to the crank shaft 1 8 L, 1 8 R. The transmission plate 30 is provided with a fixing hole 37 to which a protruding portion 38 for transmitting a pedal force described later is coupled. The drive sprocket 21 is provided with a window 3 9 which can be combined with the protruding portion 3 8 and the fixing hole 37. The protruding portion 3 8 penetrates this window 3 9 12 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 fits into the fixing hole 37. Straddle the drive sprocket 21 and the transmission plate 30 to form a plurality of (here 3) small windows 40 different from the aforementioned window 31, and the compression spirals are housed inside the small windows 40, respectively. Spring 4 1. The compression coil spring 41 is arranged so that the transmission plate 30 is pressed against the side in the rotation direction 4 2. That is, acting on the direction of looseness between the absorbing sprocket 21 and the coupling portion of the transmission plate 30, the displacement of the transmission plate 30 is transmitted to the sprocket 21 with good responsiveness. Therefore, the pedaling torque applied to the crankshaft 17 by the cranks 18 L and 18 R due to the rider's pedaling is transmitted to the transmission plate 30 through the first one-way clutch 26, and this pedaling torque While compressing the compression coil springs 32 and 41, they are transmitted to the driving sprocket 21, and then transmitted to the rear wheel WR through the chain 22 and the driven sprocket 23. The assist torque given to the auxiliary sprocket 24 from the auxiliary power unit 16 described later is transmitted to the rear wheel W R through the chain 22 and the driven sprocket 23. In addition, the assist torque given to the auxiliary sprocket 24 from this auxiliary power unit 16 is not transmitted to the cranks 18 L, 18 R by the action of the first one-way clutch 26. A sensor portion 43 of a pedaling force detecting device is provided on the side of the drive sprocket 21 that is closer to the vehicle body, that is, on the downcomer 4 side. This sensor section 4 3 has an outer ring 4 4 fixed to the drive sprocket 21 and a sensor body 45 for forming a magnetic circuit that can be freely rotated with respect to this outer ring 4 4. The sensor body 45 and the bushings 46 and flanges 47 as supporting members will be described later. The outer ring 4 4 is formed of a material having electrical insulation properties, and is composed of 13 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 The illustrated bolt is fixed to the drive sprocket 21. Next, the auxiliary power unit 16 will be described with reference to FIGS. 5 to 9. The box 50 of the auxiliary power unit 16 includes a right half box 51 and a left half box 5 which is a first storage chamber 5 4 formed between the right half box 51 and the right half box 5 2. Here, A cover 5 3 is formed between the left half case 5 2 and the second storage room 55 and is combined with the left half case 5 2. On the box 50, an electric motor 15 having an axis parallel to the rotation axis of the crank shaft 17 is mounted. The rotation output of this electric motor 15 should assist the pedaling torque applied to the cranks 18L, 18R, and transmit it to the auxiliary sprocket 24 through the auxiliary reduction gear set 56. On the left half box 52 of the box 50, a fitting cylindrical portion 7 4 protruding toward the side opposite to the cover 53 and a bottomed cylindrical motor case 75 having an electric motor 15 are integrally provided. In a state of being fitted on the fitting cylindrical portion 74, a plurality of (for example, three) bolts are fastened in the screw holes 7 6 of the left half case 5 2. In addition, the motor shaft 57 can freely rotate through the support wall portion 77 and protrude toward the second storage chamber 55, and a ball bearing 91 is installed between the motor case 75 and the motor shaft 57 connected to the support wall portion 7-7. The motor case 75 is formed by, for example, a one-piece mold. The rotation shaft of the reduction gear set 5 6 for transmitting the power of the electric motor 15 to the auxiliary sprocket 24 is a first rotation shaft 59 having an axis parallel to the motor shaft 57 and a rotation shaft 1 rotating shaft 5 9 second parallel rotating shafts 6 4 are configured. A ball bearing 6 9 is installed between the first rotation shaft 5 9 and the left half case 5 2, and a ball bearing 7 0 is installed between the right half case 51 and the first rotation shaft 5 9. The first rotation shaft 5 9 is Freely rotatable. In addition, at 14 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 A ball bearing 71 is installed between the left half casing 5 2 and the second rotation shaft 64, and a ball bearing 7 2 is installed between the right half casing 51 and the second rotation shaft 64. The second rotation shaft 64 is possible. It is arranged to rotate freely. In addition, it includes a primary reduction drive gear 5 8 fixed to the motor shaft 5 7 of the electric motor 15 in the second storage chamber 5 5, and bolts 6 0 in the second storage chamber 5 5. Primary reduction driven gear 6 fixed to the first rotation shaft 5 9 and meshing with the primary reduction drive gear 5 8 1. It is integrated with the first rotation shaft 5 9 in the first storage chamber 5 4. The secondary reduction driving gear 62 is fixed to the second rotation shaft 64 in the first storage chamber 54 and the secondary reduction driven gear 62 is meshed with the secondary reduction driving gear 62. The secondary reduction gear 6 is provided at The second one-way clutch 6 5 between the second reduction driven gear 6 3 and the second rotating shaft 6 4, and the auxiliary sprocket 2 4 is fixed to the right half of the case 5 1 outward from the second rotating shaft 6 4. On the protruding part. The sealing member 66 is provided at a portion protruding from the right half casing 5 1 to the second rotation shaft 64. To reinforce the primary reduction driven gear 6 1 on the side of the secondary reduction driven gear 6 2 of the primary reduction driven gear 6 1, a ring-shaped reinforcing plate 67 is tightened with bolts 6 8. In addition, by forming a plurality of ribs 73 on the inner side of the cover 48 (on the side of the second storage chamber 55), the rigidity of the cover 48 can be improved. In addition, the cover 48 is formed by pouring a resin material into the mold, and by forming the inside shape of the cover 48 as described above, the flow of the resin material when the cover 48 is manufactured can be improved. In such a reduction gear set 56, the rotation accompanying the operation of the electric motor 15 is decelerated and transmitted to the auxiliary sprocket 2 4 when the operation of the electric motor 15 is stopped and the rotation ratio of the driving sprocket 21 is assisted. When the sprocket 24 rotates fast, the second one-way clutch 65 allows the second rotating shaft 15 312 / Invention Manual (Supplement) / 92-12 / 92125190. 200406335 64 idling. This does not hinder the rotation of the auxiliary sprocket 24 depending on the pedaling torque from the cranks 18L, 18R. However, the auxiliary power unit 16 is supported by the support pipe 5 and the support members 9 L and 9 R and is disposed below the rear fork 9. At this time, the motor shaft 5 7 is positioned on the crank slightly lower than the crank shaft 17. In the vicinity of the pedal, the motor shaft 57 and the first rotation shaft 59 are juxtaposed in a side view so as to be slightly parallel to the ground. In addition, the second rotation shaft 64 is positioned higher than the first rotation shaft 59, and is formed so as to protrude a part of the box 50 that covers the secondary reduction driven gear 6 3 fixed to the second rotation shaft 6 4. The protruding part 84 is arranged such that the auxiliary power unit 16 ° is positioned in front of the rear wheel WR and can be inserted between the left and right pair of supporting members 9L and 9R from below. At this time, the auxiliary power unit is fixed to the supporting tube The brackets 7 and 9 of 5 are fastened with bolts and nuts to a suspension portion 80 that is swelled to the upper part of the front upper part of the left half of the housing 5 2 and the support members 9 are fastened to the left and right pair. The brackets 8 1 on the L and 9 R are sandwiched between the suspension portions 8 2 which are provided to be swollen upwards and upwards, and are fastened by bolts and nuts (the suspension portions 8 0, 8 2 And the state in which the auxiliary power unit 16 is mounted on the electric assist bicycle 1 is shown in FIG. 2 (A). In addition, the upper part of the protrusion 8 4 of the box 50 is arranged in a rear view from the perspective of a plan view. And the upper surface of 9 is almost the same. In addition, the second rotating shaft 64 is projected from the right half of the housing 51. At the branch, a support member 8 3 extending rearward is formed, and the idler wheel 25 can be pivotally supported at the end of this support member 8 3 so that the right half of the box 5 1 and 16 312 / Invention Specification (Supplement) ) / 92-12 / 92125190. 200406335 The idler wheels 25 are integrated. As described above, the protruding portion 84 of the box 50 may only protrude so as to cover the portion opposed to the secondary reduction driven gear 63, and thus has a shape that extends slenderly in the front-rear direction. In this way, even with an ordinary bicycle stand, this protruding portion can be inserted from below between the left and right pair of supporting members constituting the rear fork, and the auxiliary power unit 16 is arranged, so there is no need to prepare a special stand, which can reduce the manufacturing cost. In addition, by disposing the auxiliary power unit 16 having a large weight under the vehicle body frame 2, the position of the center of gravity can be lowered, and the stability during traveling can be improved. In addition, since the auxiliary power unit 16 is not arranged in the space above the rear fork 9 and in the rear space of the seat tube 12, this space can be effectively used. As explained in this embodiment, a battery storage box 13 and Electric equipment box 1 4 and so on. In addition, since the position of the auxiliary power unit 16 is near the driving sprocket 21 and the chain 2 2 hung on the driving sprocket 21, the existence of this auxiliary power unit 16 can be made inconspicuous, especially Covering it with a chain cover makes it less noticeable. In addition, by arranging the motor shaft 57 and the first rotation shaft 59 in parallel with the ground, and arranging the second rotation shaft 64 above the first rotation shaft 59, the bottom surface of the auxiliary power unit 16 can be secured. At a certain height from the ground, the winding angle of the chain 22 with respect to the auxiliary sprocket 24 fixed to the second rotation shaft 64 can be secured to a certain degree. Next, the electric motor 15 constituting the auxiliary power unit 16 will be described with reference to Figs. 10 to 13. The electric motor 15 is a brushless DC motor driven by a DC power source. It has a motor shaft 57 and stators 85 and 17 arranged around the motor shaft 57. 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 The rotor 8 6 fixed to the motor shaft 57 and the rotor position detector 8 7 which detects the position of the rotor are covered by the motor case 7 5 as a whole. The stator 85 is configured by winding a stator coil 89 around a stator core 88, and a plurality of stators 85 are provided along the inner peripheral surface of the motor case 75 (nine in this case). In addition, the rotor 86 is provided with a plurality of (here, eight) permanent magnets 90 as opposed to the above-mentioned stator 85, and the magnetic poles facing the stator 85 of this permanent magnet 90 are arranged alternately with N poles and S poles. At this time, a certain gap is formed between the stator 85 and the rotor 86. In addition, ball bearings 9 1 and 9 2 are installed between the motor shaft 57 and the motor case 7 5 to support the motor shaft 57. In addition, a plurality of (here, three) brackets 9 3 are formed on the side of the motor case 7 5 and on the projecting side of the motor shaft 57, and bolts pass through the through holes of the brackets 9 3. The electric motor 15 is fixed to the box 50. In addition, the rotor position detector 8 7 is arranged so as to be parallel to the upper surface of the rotor 8 6 with a certain gap. The Hall element included in the rotor position detector 87 is used to detect the movement to the rotor position detector 87. The N pole of the lower rotor 86. The stator coil 89, which is wound around the stator core 88, is electrically connected in the order shown in Fig. 13 and has three-phase (U, V, W-phase) input terminals 94. The voltage applied to this input terminal 9 4 is controlled by the control device in the electrical box 14 and is supplied from the battery B. If a pulse voltage of 120 degrees in phase is applied to the input terminal 9 4, a plurality of The magnetic poles N and S of the stator 85 appear alternately, and the magnetic poles of the stator 85 are moved in accordance with the frequency of this pulse. In this way, the rotor detected by the rotor position detector 87 is obtained through the electrical component box 14 The position of 8 6 permanent magnets 9 0 passed according to this 18 312 / Invention Specification (Supplement) / 92-12 / 92125190. The position of the 200406335 permanent magnets 90 adjusts the pulse voltage applied to the stator 85 to rotate the motor shaft 57. In addition, by controlling the PWM of the pulse amplitude of the pulse voltage applied to this input terminal 94, the rotation speed of the rotor (the output of the motor) can be controlled. In addition, since the rotor position detector 8 7 detects the N pole of the permanent magnet 90 moving below the turning position detector 8 7, the number of times of the detection signal of the N pole can be used to calculate the axle 5 7 through this number of times. Number of revolutions (speed). In the electric assist bicycle 1 configured as described above, the driving directions (forward rotation directions) of the cranks 1 8 L and 1 8 R rely on human power, and the inner wheels 27 fixed to the cranks 17 are rotated, and the rotation is passed through the ratchet claws. 3 5 passes to the gear teeth. Then, the transmission plate 30 is rotated, and this rotation is transmitted to the driving sprocket 21 by the compression coil spring 32, and the torque of the transmission plate 30 is not transmitted due to the torque on the driving sprocket 21. It is immediately transmitted to the drive chain 21. First, due to the torque compression of the coil spring 32, the drive sprocket 21 is rotated when the deflection load and the torque are balanced. In this way, the transmission plate 30 and the driving sprocket 21 are rotated in an offset state having a direction corresponding to the torque, and the rear wheel W R is driven by the chain 22. The torque applied to the moving sprocket 21 is detected as the force of the rider pedaling the cranks 18 L, 18 R, that is, the pedaling torque. Since the protruding portion protruding from the sensor body 4 3 of the pedaling force detecting device rotates at the same time as the transmission plate 30, the pedaling force transmitting ring 9 5 (hereinafter, corresponding to the outer ring 4 4, which supports this protruding portion 38) The pedaling force transmission ring is called the inner ring 9 5) and the outer ring 4 4 312 / Invention Specification (Supplement) / 92-12 / 92125190 fixed to the drive sprocket 21. The number of sub-86, the number of sub-axes, and the ratcheting of the spinner can be determined. The relative position and torque are determined based on the 38, 95, and 19 200406335. This relative position is detected by the sensor body 43 and provided to a control device (to be described later) for detecting pedaling force. This sensor body 43 will be described in detail with reference to FIGS. 14 and 15. The outer ring 4 4 is formed of a material having electrical insulation properties, and three bolt holes 9 6 are provided, so that the bolt for fixing this outer ring 4 4 to the drive sprocket 21 can be penetrated. A first inductor 9 7 A is disposed along the inner peripheral surface of the outer ring 44, and a second inductor 9 7 B adjacent to the first inductor 9 7 A is also disposed. In addition, an inner ring 95 is arranged on the second induction body 9 7 B along the outer peripheral surface. The first inductor 9 7 A and the second inductor 9 7 B are made of a highly conductive material such as aluminum or brass or a soft magnetic material, and are fixed to the outer ring 44 and the inner ring 95 as described later. Two sets of ring-shaped core plates 9 8 and 9 9 are provided between the first inductor 97A and the second inductor 97B, and a magnetic core collar is provided on the inner peripheral side of these core plates 9 8 and 9 9. 1 0 0. The magnetic core plates 9 8 and 9 9 and the magnetic core collar 100 are composed of a soft magnetic material such as soft iron oxide. The coil 101 is wound around the outer periphery of the magnetic core collar 100, and passes through the magnetic core plates 98, 99, and the magnetic core collar 100, as well as the first inductor 97A and the second inductor 97B. The magnetic flux generated when the coil 101 is energized passes through to form a magnetic circuit. The magnetic core plates 9 8 and 9 9 and the magnetic core collar 100 are supported by a sleeve 46 and a flange 47 having an external thread matching the internal thread of this sleeve 46. In addition, the sleeve 46 and the flange 4 7 are supported by the support pipe 5 to restrict rotation. A lead wire 104 for supplying a current to the coil 101 is passed through the sleeve 46 and led out to the outside, and is connected to a control device 110 described later. On the outer ring 4 4 20 312 / Invention specification (supplement) / 92-12 / 92125190. 200406335 and bushing 4 6 are provided with an oil seal 105, between the outer ring 4 4 and the inner ring 95, and between the inner ring 95 and the flange 47, respectively, seals 1 0 6, 1 0 7. A projection 38 protruding from the inner ring 95 at a right angle is provided so as to project outward from the opening 4 8 A provided in the cover 4 8 so as to fit the fixing hole 37. FIG. 16 is a front view of the first induction body 97A, and FIG. 17 is a cross-sectional view. The first induction body 97A has a ring shape as a whole, and a plurality of teeth 108 are formed on its inner periphery. The second induction body 97B is also provided with the same teeth as these teeth 108. The overlapping of these teeth forms part of the path of the magnetic flux generated by the coil 101. At two places of the teeth 108, protrusions 109A protruding from the bottom of the cover-shaped first induction body 97A are formed. The projecting portion 10 9 A is set so that the first inductor 9 7 A can be rotated integrally with the outer ring 4 4 and fitted with a recessed portion formed in the outer ring 4 4. FIG. 18 is a cross-sectional view of the second inductor 9 7 B. FIG. The second inductor 9 7 B has the same shape as the first inductor 9 7 A. However, the outer periphery is smaller than the first sensor 9 7 A. In addition, as shown in FIG. 18, the second inductor 9 7 B has a protruding portion 10 9 B projecting outward from the bottom of the hat-shaped second inductor 9 7 B. This protruding portion 1 0 9 B is set in such a manner that a recessed portion formed in the inner ring 9 5 in contact with the second inductor 9 7 B is fitted. FIG. 19 is a schematic diagram showing a magnetic circuit penetrating through the magnetic flux generated by the coil 101. In this figure, the magnetic flux Φ generated when the coil 101 is energized includes a core plate 9 8, 9 9 and The magnetic core collar 100 has a magnetic circuit of a first inductor 9 7 A ′ and a second inductor 9 7 B. At this time, the direction of the magnetic flux? Is, for example, as shown in Fig. 19. Here, the impedance of the coil 1 0 1 is used magnetic flux Φ 21 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 The impedance of the passing circuit, which is a function of the impedance of the magnetic circuit. In addition, the magnetic flux Φ substantially passes through the teeth (the teeth 1 0 8 on the first inductor 9 7 A) provided on the inner periphery of the first inductor 97A and the second inductor 97B, so the magnetic circuit in this part The impedance is determined by the overlapping amount of the teeth of the first inductor 9 7 A and the second inductor 9 7 B. As described above, the outer ring 44 and the inner ring 95 are shifted in accordance with the pedaling torque, and the relative positions of the first inductor 9 7 A and the second inductor 9 7 B are also offset. As a result, the degree of overlap of the teeth of the first induction body 9 7 A and the second induction body 9 7 B also changes in accordance with the pedaling torque. FIG. 20 is a diagram showing that the teeth of the first inductor 9 7 A and the second inductor 97B have different degrees of overlap with each other depending on the pedaling torque. As can be seen from these figures, when the pedaling torque is small, the degree of overlap between the first inductor 97 A and the second inductor 9 7 B increases. Therefore, the first inductor 9 7 A and the second inductor 9 7 are used. The ratio of the teeth of B to be shielded by the magnetic flux between the magnetic core plates 9 8 and 9 9 is reduced, so the magnetic circuit impedance becomes smaller. In addition, when the pedaling torque is large, the degree of overlap of the first inductor 9 7 A and the second inductor 9 7 B is small, so the teeth of the first inductor 97A and the second inductor 9 7 B The ratio of the magnetic flux shielding between the magnetic core plates 9 8 and 9 9 increases, so the magnetic circuit impedance becomes large. In this way, the impedance of the path through which the magnetic flux passes changes according to the pedaling torque, so by detecting the impedance of the coil 1 0 1 as a function of the impedance of this magnetic circuit, the pedaling torque can be detected. As shown in Figure 21, 22 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 Control device 1 1 0 The oscillation circuit 1 1 1, the peak hold circuit 1 1 2, and the impedance 1 1 3 together with the coil 1 0 1 constitute the main part of this control device 1 1 0. The output of the peak hold circuit 1 1 2 is processed by C P U 1 1 4. The oscillation circuit 1 1 1 outputs an alternating current of a predetermined frequency (the waveform at a point a in FIG. 2 is shown in FIG. 2 (A)). When the degree of overlap of the teeth of the first inductor 9 7 A and the second inductor 9 7 B is large, the magnetic circuit impedance of the magnetic flux Φ generated in the coil 1 01 is large, so the waveform at the point b The amplitude becomes larger (the waveform with an increase in pedaling force at point b in FIG. 21 is shown in FIG. 2 (B)). The amplitude of the point b is held by the peak holding circuit 1 12, and the peak holding value, that is, the value of the point b (refer to FIG. 2 (C)) is inputted to C P U 1 1 4 as the pedaling torque. The electric motor 15 constituting the auxiliary power unit 16 is connected to the control device 110 as a load, and a battery B is connected as a power source. The driving circuit of the electric motor 15 is composed of F E T 1 1 7, a diode 1 1 8, and a capacitor 1 1 9. The positive electrode of battery B is connected to the positive terminal of the electric motor 15 through contact 120, and the negative electrode of battery B is connected to the negative terminal of the electric motor 15 through F E T 1 1 7. The contact 1 2 0 performs a 0 N operation according to the energization of the coil 1 2 1 according to the instruction of C P U 1 1 4. The current supplied to the electric motor 15 is determined by the voltage applied to the gate of F E T 1 1 7 from C P U 1 1 4. CPU 1 1 4 refers to the pedaling torque value / voltage table corresponding to the pedaling force value, or calculates according to a predetermined calculation formula to obtain a voltage value corresponding to the pedaling torque value, and adds this voltage to the FET 1 1 7 On the gate. It is desirable to set the pedaling torque value / voltmeter or calculation formula so that the value of the pedaling torque input to C P U 1 1 4 increases while the output of the electric motor 15 increases. 23 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 According to this embodiment, for example, a deviation in assembly accuracy occurs, and the positions of the core plates 9 8 and 99 are shifted in the axial direction between the first inductor 9 7 A and the second inductor 9 7 B. When the distance between the first inductor 9 7 A and the magnetic core plate 98 is narrowed, the distance between the second inductor 9 7 B and the magnetic core plate 99 is increased. In contrast, when the distance between the first inductor 9 7 A and the core plate 98 is increased, the distance between the second inductor 9 7 B and the core plate 99 is reduced. In this way, the variation of one interval is offset by the variation of the other interval, and the overall magnetic circuit impedance can be maintained constant. In addition, between the first inductor 97A and the second inductor 97B, the positions of the magnetic core plates 9 8 and 9 9 are shifted in the radial direction, and the first inductor 9 7 A and the second When the overlap between the inductor 9 7 B and the core plates 9 8 and 9 9 increases, on the other side in the radial direction, the first inductor 97A and the second inductor 9 7 B and the core plates 9 8 and 9 9 The overlap becomes smaller. Therefore, the impedance of one magnetic circuit increases and the impedance of the other magnetic circuit decreases. As a result, the overall magnetic circuit impedance can be maintained constant. In addition, the electric assist bicycle 1 of the present invention is provided with a limiter. When the electric assist bicycle 1 travels at a speed exceeding a predetermined speed, the assist unit is stopped regardless of the output from the pedaling force detection device, and the assist torque is not generated. In order to detect the traveling speed of the electric assist bicycle 1, the control uses the detection signal of the N pole detected by the rotor position detector 87 of the electric motor 15 described above. The number of N poles of the permanent magnets 90 fixed to the rotor 8 6 of the electric motor 15 is determined by the motor (here, 4 poles), and the N poles output from the rotor position detector 8 7 are detected by counting The signal can get the number of revolutions (speed) of the electric motor 15. 24 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 When the cyclist steps on the cranks 1 L and 18 R to increase the pedaling torque, as described above, the electric motor 15 is driven by the control circuit 110, from the auxiliary sprocket 2 of the auxiliary power unit 16 to the chain 2 2 Add auxiliary torque. At this time, since the second one-way clutch 65 constituting this auxiliary power unit 16 is connected, the rotation of the motor shaft 57 of the electric motor 15 and the rotation of the auxiliary sprocket 24 are proportional to the gear ratio of the reduction gear set 56. In this way, the speed of the electric assist bicycle 1 can be obtained from the number of revolutions of the motor shaft 57 of the electric motor 15. In addition, the cyclist's pedaling torque is added to the cranks 18L and 18R. If the vehicle speed increases and exceeds the prescribed speed, the electric motor 15 of the auxiliary power unit 16 stops without adding the auxiliary torque. However, since the second The one-way clutch 65 slides and does not apply torque from the chain 22 to the auxiliary power unit 16 and the auxiliary power unit 16 does not hinder the rotation of the crank pedal by the cranks 18L and 18R. As for the limiter for controlling the assist torque based on the vehicle speed, the output of the rotor position detector 87 of the electric motor 15 is transmitted to the above-mentioned control device 110, and the control of the electric motor 15 can be realized while the vehicle speed is calculated by the CPU 114. In addition, FIG. 21 shows a case where the control device 110 controls a DC motor having a conventional rectifying element. For the above-mentioned brushless DC motor, a three-phase pulse voltage is generated from the output of the battery B in order to control the DC motor. It is added to the electric motor 15 for correspondence. (Effects of the Invention) As can be seen from the above description, according to the electric assist bicycle of the present invention, the auxiliary power unit is disposed below the rear fork, and the housing member of the large-diameter gear that covers the reduction gear mechanism constituting the power unit is covered by the auxiliary power unit. TU 25 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 The outlet part is inserted between the pair of left and right support members from below. A bicycle stand can be used as a stand for a bicycle equipped with this power unit, which can reduce manufacturing costs. In addition, since the auxiliary power unit is arranged below the fork, the space above the rear fork and the seat tube can be effectively used, and a battery box and an electric box can be arranged. In addition, because the large auxiliary power unit is arranged below, the position of the center of gravity can be lowered. The auxiliary power unit is inconspicuous due to the stable travel of the crank pedal, the chain, and the chain cover. In addition, by arranging the upper portion of the protruding portion of the accommodating member at a position almost equal to the upper surface of the rear fork when viewed from the side, such a configuration can further lower the center of gravity position of the electric assist bicycle and stabilize it. In addition, while the motor shaft of the motor having the auxiliary power unit is located near the arranging plate, the positions of the first rotating shaft having the reduction gear mechanism of the auxiliary power unit and the motor shaft of the motor are juxtaposed horizontally relative to the ground, With such a configuration, the bottom surface of the auxiliary power unit can be secured at a certain height from the ground, and the angle of the roll transmission member on the auxiliary power transmission portion of the auxiliary power unit can be ensured. In addition, the reduction gear mechanism has a second rotating shaft, and the second rotating shaft is disposed above the first rotating shaft from the side. With this structure, the bottom surface of the auxiliary power unit can be secured at a certain height from the ground. [Brief description of the drawings] FIG. 1 is a side view of an electric assist bicycle of the present invention. 312 / Invention Specification (Supplement) / 92-12 / 92125190. It is usually reset at the rear and rear, and can be configured so that the ground is on the treadmill to assist the winding and the auxiliary winding is viewed. 26 200406335 Figure 2 is an enlarged view of the main part of the electric assist bicycle of the present invention, Figure 2 (A) is a side view when the auxiliary unit is installed, and FIG. 2 (B) is a side view when the auxiliary unit is removed. Fig. 3 is a sectional view near the crank shaft and the drive sprocket of the electric assist bicycle according to the present invention. FIG. 4 is a cross-sectional view of FIG. 3 along the line I V-IV. Fig. 5 is a sectional view taken along the line V-V in Fig. 2 (A). FIG. 6 is a cross-sectional view of FIG. 2 (A) taken along the line V I-V I. FIG. 7 is a cross-sectional view of FIG. 2 (A) along the line V I I-V I I. FIG. Fig. 8 is a side view of the left cover half. Fig. 9 is a side view of the right cover half. FIG. 10 is a sectional view of the electric motor. Fig. 11 is a sectional view taken along the line X I-X I in Fig. 10. FIG. 12 is a cross-sectional view taken along the line X I I-X I I in FIG. 10. Fig. 13 is a wiring diagram of a stator coil of an electric motor. Fig. 14 is a sectional view of a main part of a sensor portion of the pedaling force detecting device. FIG. 15 is a front view of a sensor portion of the pedaling force detecting device. FIG. 16 is a front view of the first inductor. FIG. 17 is a cross-sectional view of a second inductor. FIG. 18 is a cross-sectional view of a second inductor. Fig. 19 is a schematic diagram showing a magnetic circuit penetrated by a magnetic flux generated by a coil. Figure 20 is a diagram showing the degree of overlap between the first sensor and the second sensor, 27 312 / Invention Specification (Supplement) / 92-12 / 92125190. 200406335 Figure 20 (A) is a graph when the pedaling torque is small, and Figure 20 (B) is a graph when the pedaling torque is large. FIG. 21 is a pedaling force detection circuit of the control device. FIG. 22 is a graph showing the relationship between the voltage of the coil and the pedaling force. FIG. 22 (A) is a waveform diagram at point a in FIG. 21, and FIG. 22 (B) is a waveform at point b in FIG. 21, and FIG. 2 2 (C) is a graph showing the relationship between the coil voltage and the pedaling force at a point c in FIG. 21. (Description of component symbols) 1 Electric-assisted bicycle 2 Body frame 3 Front tube 4 Drop tube 5 Support tube 6 Seat tube 7 Front fork 8 Steering handlebar 9 Rear fork 9L, 9R Support member 10 Support rod 11 Saddle 12 Seat pillar 13 Battery storage box 14 Electric equipment box 15 Electric motor (motor) 312 / Invention manual (Supplement) / 92-12 / 92125190. 28 200406335 16 Auxiliary power unit 17 Crankshaft 1 8L, 1 8R Crank 1 9L, 1 9R Cover 20L, 20R Ball bearing 2 1 Drive sprocket 22 Chain 23 Follower key 24 Auxiliary sprocket 25 Idler 26 26 1 One-way clutch 27 Inner wheel 27 A Bushing 28 A Nut 28B Plate 29 Cover 30 Transmission plate 3 1 Window 32 Compression coil spring 33 Ratchet teeth 34 Spring 35 Ratchet pawl 36 Cover 37 Fixing hole 312 / Instruction manual (Supplement) / 92 -12/92125190.
29 200406335 38 突 起 部 39 窗 40 小 窗 41 壓 縮 螺 旋 彈 簧 42 轉 動 方 向 43 感 測 器 部 44 外 側 環 45 感 測 器 本 體 46 套 管 47 法 蘭 盤 48 罩 48A 開 π 50 箱 (收納構件） 51 右 半 箱 體 52 左 半 箱 體 53 罩 54 第 1 收 納 室 55 第 2 收 納 室 56 減 速 齒 輪 組 57 馬 達 軸 58 1 次 減 速 驅 動 59 第 1 轉 動 轴 60 螺 栓 6 1 1 次 減 速 從 動 312/發明說明書(補件)/92-12/92125190.29 200406335 38 Protrusion 39 Window 40 Small window 41 Compression coil spring 42 Direction of rotation 43 Sensor section 44 Outer ring 45 Sensor body 46 Sleeve 47 Flange 48 Cover 48A Open π 50 box (storage member) 51 right Half case 52 Left half case 53 Cover 54 First storage room 55 Second storage room 56 Reduction gear set 57 Motor shaft 58 1st speed reduction drive 59 1st rotation shaft 60 bolt 6 1 1st speed reduction driven 312 / Invention Manual (Supplement) / 92-12 / 92125190.
30 200406335 62 2次； 咸： 連‘ 驅 動 齒 63 2次； 咸： 連‘ 從 動 齒 64 第 2 轉 動 軸 65 第 2 單 向 離 合 器 66 密 封 構 件 67 增 強 板 68 螺 栓 69 滾 珠 轴 承 70 滾 珠 軸 承 71 滾 珠 軸 承 72 滾 珠 車由 承 73 肋 74 礙 合 筒 部 75 馬 達 殼 76 螺 孔 77 支 撐 壁 部 79 托 架 80 懸 掛 部 81L、 81R 托架 82 懸 掛 部 83 支 撐 構 件 84 突 出 部 85 定 子 86 轉 子 312/發明說明書(補件)/92-12/92125190.30 200406335 62 2 times; salty: with 'drive tooth 63 2 times; salty: with' driven tooth 64 2nd rotating shaft 65 2nd one-way clutch 66 seal member 67 reinforcement plate 68 bolt 69 ball bearing 70 ball bearing 71 ball Bearing 72 ball bearing 73 bearing rib 74 blocking tube 75 motor case 76 screw hole 77 support wall 79 bracket 80 bracket 81L, 81R bracket 82 suspension 83 support member 84 protrusion 85 stator 86 rotor 312 / invention Instruction (Supplement) / 92-12 / 92125190.
31 200406335 87 轉 子 位 置 檢 測器 88 定 子 磁 芯 89 繞 定 子 線 圈 90 永 久 磁 鐵 91 滚 珠 軸 承 92 滾 珠 轴 承 93 托 架 94 輸 入 端 子 95 踏 力 傳 遞 環 (内側環） 96 螺 栓 孔 97A 第 1 感 應 體 97B 第 2 感 應 體 98 環 狀 磁 芯 板 99 環 狀 磁 芯 板 100 磁 芯 軸 環 101 線 圈 104 引 出 線 105 油 封 106 密 封 件 107 密 封 件 108 齒 1 09A、 1 09B 突； 起 部 110 控 制 裝 置 111 振 盪 電 路 312/發明說明書(補件)/92-12/92125190.31 200406335 87 Rotor position detector 88 Stator core 89 Winding stator coil 90 Permanent magnet 91 Ball bearing 92 Ball bearing 93 Bracket 94 Input terminal 95 Pedal force transmission ring (inner ring) 96 Bolt hole 97A First induction body 97B Second induction Body 98 Toroidal magnetic core board 99 Toroidal magnetic core board 100 Core collar 101 Coil 104 Lead-out wire 105 Oil seal 106 Seal 107 Seal 108 Tooth 1 09A, 1 09B protruding; Starting part 110 Control device 111 Oscillating circuit 312 / Invention Specification (Supplement) / 92-12 / 92125190.
32 200406335 112 峰值 保持電路 113 阻抗 114 CPU 116 主開 關 117 FET 118 二極 體 119 電容 1 20 接點 WF 前輪 WR 後輪 B 電池 312/發明說明書(補件)/92-12/92125190.32 200406335 112 Peak hold circuit 113 Impedance 114 CPU 116 Main switch 117 FET 118 Diode 119 Capacitance 1 20 Contacts WF Front wheel WR Rear wheel B Battery 312 / Invention Manual (Supplement) / 92-12 / 92125190.