200307123 ⑴ 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之踏力檢測裝置，特別 是關於以簡單且廉價的構成可良好地檢測踏力的電動輔助 自行車之踏力檢測裝置。 【先前技術】 在倂設利用踏力的驅動系與利用電動馬達的驅動系的 電動輔助自行車，所謂的輔助（assist )自行車，以踏力 感測器檢測施加於踏板的踏力，根據其檢測結果控制電動 馬達的驅動扭矩（torque)。 第1 6圖爲具備習知的輔助自行車所使用的踏力檢測 機構的旋轉軸的剖面圖，揭示於日本專利公報第2 9 6 7 3 9 1 號等。 此旋轉軸1 0 2是以在軸方向二分割配置成同軸狀的輸 入軸1 0 2 a以及輸出軸1 〇 2 b，與插通於各輸入輸出軸1 〇 2 a 、102b的內部，在各軸l〇2a、102b與兩端部栓槽（ spline)結合的扭力棒（torsi〇n bar) 102c，與相互地朝 軸方向彈開前述各輸入輸出軸102a、102b的彈簧1 1 1爲 主要構成。 在輸入軸102a的大徑部於端面具有凸狀凸輪部921a 的滑塊（slider ) 921藉由栓槽結合容許朝軸方向的滑動 而被結合。在輸入軸1 02a的球杯（ball cup ) 924卡合一 端藉由銷（pin) 153擺動自如地支持的位移檢測桿152的 -6 - (2) (2)200307123 略中央部，在位移檢測桿1 5 2的他端連結有衝程感測器（ s t r 〇 k e s e n s 〇 r ) 1 5 0 的衝程檢測軸 1 5 1。 前述球杯924因藉由螺旋彈簧（coil spring) 199經 常被按壓於輸出軸1 〇2b側，故球杯924 —邊吸收其旋轉 一邊將前述滑塊92 1經常按壓於輸出軸i〇2b側。在前述 輸出軸1 0 2 b的端面與前述滑塊9 2 1的凸凸輪部9 2 1 a卡合 的兩個凹狀凸輪溝槽922係形成於圓周方向。 形成於前述輸入軸1 〇2a的小徑部的小徑的齒輪齒 113被輸入踏力。在輸入軸102a的齒輪齒102e由未圖示 的驅動馬達輸入輔助輸入。結接於在輸入軸1 0 2 a的小徑 部的齒輪102d與未圖示的輸出鏈輪（sprocket )軸咬合。 在這種構成中，若依照踏力使扭力棒102c扭轉的話 ，在輸入軸102a以及輸出軸102b間產生旋轉方向的相位 差，在輸出軸102b與滑塊921之間也產生相位差。若根 據此相位差球杯924在軸方向位移的話，因位移檢測桿 1 52會以銷1 53爲軸而擺動，故此擺動傳達到衝程感測器 1 5 0而被檢測。 【發明內容】 上述習知的扭矩檢測機構因零件數目多構造複雜化， 容易招致裝置的大型化或製程的繁雜化。而且，因滑動位 置或對接位置多，故必須使用耐磨耗性或耐久性優良的材 料。 本發明的目的是提供解決上述習知技術的課題，零件 (3) (3)200307123 數目少、簡單且小型，滑動位置或對接位置少的構造，同 時良好的扭矩檢測可進行的踏力檢測裝置。 爲了達成上述目的本發明爲一種電動輔助自行車之踏 力檢測裝置，包含外插於曲柄軸，一端結合於該曲柄軸， 他端結合於踏板鏈輪的扭力棒，以輸入該曲柄軸的踏力作 爲該扭力棒的扭轉量而檢測，在採取如以下的手段的點具 有特徵。 (1 )、其特徵爲具備：配置於扭力棒的一端側以及他 端側，沿著圓周方向以微小的間距施以磁化的一對磁鐵環 ，與感應該磁性體的磁氣感測器，與對磁鐵環彈性地使該 磁氣感測器接觸的支持手段。 (2)、其特徵爲具備：配置於扭力棒的一端側以及他 端側，沿著圓周方向以微小的間距施以磁化的一對磁鐵環 ，與感應該磁性體的磁氣感測器，與具備對預定的被對接 體彈性地對接的對接部，對磁鐵環彈性地使該磁氣感測器 接觸的支持手段。 (3 )、其特徵爲具備：配置於扭力棒的一端側以及他 端側，沿著圓周方向以微小的間距施以磁化的一對磁鐵環 ，與包含磁氣感測器的磁氣感測器單元，與該磁氣感測器 與該磁鐵環保持預定的間隙而面對以固定該磁氣感測器單 元的固定手段。 如果依照上述特徵（1 )，因可對磁鐵環彈性地使磁 氣感測器接觸，故即使曲柄軸偏心也能經常保持磁氣感測 器與磁鐵環的相對位置關係於一定。 -8- (4) (4)200307123 如果依照上述特徵（2 )，若使支持手段的對接部對 接於磁鐵環或與該磁鐵環同樣偏心的被對接體的話，因若 曲柄軸偏心的話，據此磁氣感測器也同樣地位移，故即使 曲柄軸偏心也能經常保持磁氣感測器與磁鐵環的相對位置 關係於一定。 如果依照上述特徵（3 )，因磁氣感測器對車體框架 被強固地固定，故可經常保持磁氣感測器與磁鐵環的位置 關係於一定。 【實施方式】 以下參照圖面詳細說明本發明的較佳實施形態。第1 圖是裝設本發明的踏力感測器的電動輔助自行車的側面圖 〇 電動輔助自行車1爲折疊型，使車體框架4在車體的 前後方向的大致中央部可折疊而由前框架2與後框架3構 成，各框架2、3藉由連結部1 〇連結。在前框架2的前端 部配設有頭管（head pipe ) 5，在此頭管5安裝前輪7以 及把手（handle) 8的前叉（front fork) 6係操舵自如地 被支持。 在後框架3的前端結合有朝後斜上方延伸的薄板支持 框架1 1，在配設於此薄板支持框架1 1的後端部的薄板柱 (sheet post)安裝部11a上下動作自如地安裝有薄板柱 13，更於薄板柱 13上安裝有車座（saddle ) 14。在薄板 柱安裝部11 a配設有薄板柱高度調整用桿1 2。在後框架3 -9- (5) (5)200307123 的後端部軸支承有後輪1 5，在下方裝設有後述的曲柄單 元(crank unit) 50〇 在前述把手8配設有手柄8a以及煞車桿8b，在車體 前部、後部分別配設有前煞車1 7、後煞車1 8。在後輪：[5 的輪轂（hub )作爲輔助動力源的馬達1 6配設於同軸上。 馬達1 6爲高扭矩且低摩擦的三相無刷馬達較佳。 結合於踏板（pedal) 24的曲柄21結合於曲柄軸23 。在曲柄軸2 3經由之後詳述的踏力感測器（s e n s 0 r )結 合有踏板鏈輪2 5，施加於踏板24的踏力經由踏力感測器 傳達到踏板鏈輪25。踏板鏈輪25經由鏈條（chain) 27 結合於後輪的從動鏈輪（未圖示）。在車體中央部收納有 成爲馬達1 6等的電源的電池9。 第2圖爲模式地表現前述電動輔助自行車的動力傳達 機構的圖，與前述同一的符號表示同一或同等部分。 由踏板24輸入的踏力經由曲柄軸23、踏板鏈輪25 以及鏈條27輸入到後輪1 5的從動鏈輪26，在藉由變速 機3 0的齒輪機構減速後與馬達1 6所產生的輔助動力合成 以驅動後輪1 5。 第3圖爲馬達16的剖面圖，組裝變速機的汽缸（ cylinder) 3〇被軸31支持。在汽缸30的外圍嵌合有輪轂 (wheel hub) 32。輪轂32爲具有內筒以及外筒的環狀體 ，內筒的內周面對接於汽缸3 0的外圍。在輪轂3 2的側面 由汽缸30突出的連結板33被螺栓（bolt ) 34固定。在輪 轂3 2的外筒的內周，構成馬達1 6的轉子側磁極的銨磁石 -10- (6) (6)200307123 3 5隔著預定間隔被配置。即外筒爲構成保持磁石3 5的轉 子鐵心（rotor core)。 在輪轂3 2的內筒的外圍嵌合軸承3 6，在此軸承3 6 的外圍嵌合定子（stator)支持板37。在定子支持板37 的外圍配置有定子38，藉由螺栓40安裝。定子38是用 以與轉子鐵心即輪轂3 2的外筒具有預定的間隙而配置， 在此定子3 8捲裝有三相線圈3 9。 在定子支持板37的側面配設有以霍爾（Hall)元件 構成的磁極感測器4 1。磁極感測器4 1感測由前述輪轂3 2 突出配設的磁石4 2通過時的磁通量變化，輸出作爲轉子 的輪轂3 2的位置訊號。磁極感測器4 1對應馬達1 6的各 相配設於三個位置。 在定子支持板3 7的側面配設有藉由來自磁極感測器 4 1的位置訊號進行對前述三相線圈3 9的通電控制用的控 制基板43，在此控制基板43上裝設有CPU或FET等的 控制元件。此外，控制基板43可與前述磁極感測器4 1用 的安裝基板一體化。 在輪轂3 2的外圍固定有與未圖示的後輪的輪緣（rim )連結的輪幅（spoke) 44。再者，在定子支持板37的與 裝設有前述控制基板43等的側相反側藉由螺栓45固定有 托架（bracket) 46，托架46在前述車體框架4的板（ plate) 29被未圖示的螺栓結合。 第4圖爲裝設於前述框架下部的曲柄單元5 0的側面 剖面圖，在該曲柄部裝設有踏力檢測裝置500。第5圖爲 -11 - (7) (7)200307123 沿著曲柄軸的剖面圖。 曲柄單元50如第4圖所示，在前述框架下部於三個 位置以螺絲固定。在曲柄單元5 0如第5圖所示，曲柄軸 23的一端被軸承5 1旋轉自如地軸支承。在曲柄軸23的 外圍插入貫穿有筒狀的扭力棒5 3，其一端在前述軸承5 1 的附近被栓槽結合於曲柄軸23的外圍面，其他端藉由軸 承5 2對曲柄單元5 0旋轉自如地被軸支承。在前述曲柄軸 2 3的他端側的外圍面咬合有前述踏板鏈輪2 5。 在前述扭力棒5 3的一端側附近以及他端側附近的外 側面沿著圓周方向裝設有一對磁鐵環（magnet ring) 55 ( 5 5a、5 5b )。磁鐵環55是藉由沿著圓周方向以微小的間 距實施磁化而構成。在與前述磁鐵環5 5面對的位置配置 有一對 MR 感測器 5 0 1 ( 5 0 1 a、5 0 1 b )。 第6圖是顯示前述MR感測器5 0 1的安裝構造的一例 的剖面圖，MR感測器501係搭載於感測器基板5 02的一 方的主面上。MR感測器5 0 1的檢測訊號經由裝具（ harness) 503引出到外部。 前述感測器基板5 0 2被固定於略L形的板彈簧5 0 6的 一端。前述L形板彈簧5 0 6的他端係使前述MR感測器 5 〇 1藉由板彈簧5 0 6的彈性力對磁鐵環5 5彈性地接觸而 藉由螺絲5 0 5固定於曲柄單元5 0的底面。 如果依照這種感測器安裝構造，因可使MR感測器 5 0 1對磁鐵環5 5彈性地接觸，故即使曲柄軸2 3偏心也能 經常保持MR感測器5 0 1與磁鐵環5 5的相對位置關係於 -12- (8) (8)200307123 一定。因此，無論曲柄軸2 3的偏心，可以簡單的構造正 確地檢測扭力棒5 3的扭轉量所代表的踏力。 第7圖是顯示前述MR感測器5 0 1的安裝構造的其他 一例的剖面圖，前述感測器基板5 0 2被固定於略L形的 板彈簧5 0 7的一端。前述L形板彈簧5〇7的他端在互相卡 合的一對夾持具5 0 8的一方（5 0 8 a )藉由螺絲5 0 9固定。 前述一對夾持具5 0 8經由螺旋彈簧（c〇il spring) 510相互彈開而卡合。前述一對夾持具508的他方（ 508b )係使其一方（5 0 8 a )對磁鐵環5 5的預定位置彈性地對 接而藉由螺絲5 0 5固定於曲柄單元5 0的底面。 前述MR感測器5 0 1以及夾持具5 0 8在一方的夾持具 5〇8a對接於磁鐵環55的預定位置的狀態下，MR感測器 5 0 1彈性地接觸於磁鐵環5 5的其他預定位置，而預先相 對地被定位。 如果依照這種感測器安裝構造，曲柄軸23偏心夾持 具5 0 8 a位移的話，因據此MR感測器5 0 1也同樣地位移 ，故即使曲柄軸2 3偏心也能使MR感測器5 0 1對磁鐵環 5 5經常正確地定位。 第8圖是顯示前述MR感測器5 0 1的安裝構造的再其 他一例的剖面圖，前述感測器基板5 0 2被固定於板彈簧 5 1 1的一端。在前述板彈簧5 1 1的他端形成有鋸齒形彈簧 部5 1 1 a，在可相互滑動組合的一對夾持具5 i 2 ( 5丨2a、 51 2b)的面對面間，以其彈性力使一方的夾持具512a對 他方的夾持具5 1 2 b朝曲柄方向彈開而收納。他方的夾持 -13- (9) 200307123 具5 12b係使一方的夾持具512a的對接部對磁鐵環55 預定位置彈性地對接而藉由螺絲5 0 5固定於曲柄單元 的底面。 前述MR感測器5 0 1以及夾持具5 1 2在一方的夾持 5 12a對接於磁鐵環55的預定位置的狀態下，MR感測 5 0 1彈性地接觸於磁鐵環5 5的其他預定位置，而預先 對地被定位。 如果依照本實施形態，不另外準備螺旋彈簧，可得 與前述第7圖的安裝構造同等的功效。此外，在第7 圖的安裝構造雖然以夾持具的一方對磁鐵環對接者來說 ，惟使其對接於曲柄軸2 3或扭力棒5 3等與磁鐵環5 5 樣偏心的其他被對接體也可以。 第9圖是顯示前述MR感測器5 0 1的安裝構造的再 他一例的圖，前述感測器基板5 0 2被固定於略L形的夾 具5 〇4的一端。前述L形夾持具5〇4的他端係令MR感 器5 0 1與磁鐵環5 5的間隙保持於預定値（例如5 0微米 而藉由螺絲5 0 5固定於曲柄單元5 0的底面。 如果依照這種感測器安裝構造，因可使MR感測 5〇1與磁鐵環55非接觸，故MR感測器501以及磁鐵 5 5的耐久性提高。 第1 〇圖是顯示本實施形態中的踏力檢測電路的主 部位的構成的方塊圖，在各MR感測器5 0 1串聯連接有 照磁力電阻値變化的兩個可變電阻體R 1、R2。 在各MR感測器5 0 1 a ( 5 0 1 b )的輸出訊號V 1、V2 的 50 具 器 相 到 8 明 同 其 持 測 ) 器 環 要 依 若 -14- (10) 200307123 在前述扭力棒5 3發生扭轉的話，如第1 2圖所示僅發 因於在製造組裝時所產生的偏差的若千初期相位差 。相對於此，若在扭力棒5 3發生扭轉的話，如第13 示對各輸出訊號VI、V2加入前述初期相位差0 ref， 生依照扭力棒5 3的扭轉量即踏力的相位差0 F。 在本實施形態爲了定量地檢測代表前述踏力的相 (9 F，各M R感測器5 0 1 a ( 5 0 1 b )的輸出訊號 V 1 ( 經由局通濾波器（high-pass filter) ( HP F ) 2 0 2a ( )、限幅放大器（limit amplifier) 203a ( 203b)以 形整形用的比較電路（comparator) 204a ( 204b)， 到內裝計數器（counter)的CPU205。CPU205如第： 所示計數輸出訊號V2對輸出訊號V 1的延遲時間η 輸出訊號V 1的週期Ν，根據下式（1 )求出相位差0 相位差 0 F = n/N.3 60 [度]-0 ref ... ( 1 ) 此處，相位差與踏力因如第1 4圖所示顯示線性 性，故若可檢測相位差0 F的話，僅藉由將相位差0 入簡單的比例式就能求出踏力。 第1 1圖是顯示踏力檢測電路的其他實施形態的 部位的構成的方塊圖，在各MR感測器5 0 1依照磁力 値變化的四個可變電阻體R 1〜R4連接成橋狀，兩個 成爲逆相位。因若使用這種橋式電路的話可使雜訊被 ，故可更正確地求出踏力。 【發明的功效】 生起 Θ ref 圖所 更產 位差 V2 ) 202b 及波 輸入 15圖 以及 F 〇 的特 F代 主要 電阻 輸出 降低 - 15- (11) (11)200307123 如果依照本發明，可達成如以下的功效。 (1 )、如果依照申請專利範圍第1、2項的發明，目 可對磁鐵環彈性地使磁氣感測器接觸，故即使曲柄軸偏心、 也能經常保持磁氣感測器與磁鐡環的相對位置關係於—g 〇 (2 )、如果依照申請專利範圍第3、4、5、6項的發 明，因若曲柄軸偏心的話，據此磁氣感測器也同樣地位移 ，故即使曲柄軸偏心也能經常保持磁氣感測器與磁鐵環的 相對位置關係於一定。 (3 )、如果依照申請專利範圍第7項的發明，因磁 氣感測器對車體框架被強固地固定，故可經常保持磁氣感 測器與磁鐵環的位置關係於一定。 【圖式簡單說明】 ' 第1圖是裝設本發明的踏力感測器的電動輔助自行車 的側面圖。 第2圖是模式地表現電動輔助自行車的動力傳達機構 的圖。 第3圖是驅動馬達的剖面圖。 第4圖是曲柄單元的側面圖。 第5圖是沿著曲柄單元的曲柄軸的剖面圖。 第6圖是顯示MR感測器的安裝構造的一例（其一） 的圖。 第7圖是顯示MR感測器的安裝構造的一例（其二） -16- (12) 200307123 的圖。 第8圖是顯示MR感測器的安裝構造的一例（其三） 的圖。 第9圖是顯示MR感測器的安裝構造的一例（其四） 的圖。 第1 〇圖是踏力檢測電路的主要部位的方塊圖（其一 )°200307123 玖 说明, Description of the invention [Technical field to which the invention belongs] The present invention relates to a pedaling force detection device for an electric assisted bicycle, and more particularly to a pedaling force detection device for an electric assisted bicycle that can detect pedaling force with a simple and inexpensive configuration. [Prior art] An electric assist bicycle equipped with a driving system using a pedaling force and a driving system using an electric motor, a so-called assist bicycle, detects a pedaling force applied to a pedal with a pedaling force sensor, and controls electric power based on the detection results. Torque of the motor. Fig. 16 is a cross-sectional view of a rotating shaft including a pedaling force detecting mechanism used in a conventional assist bicycle, and is disclosed in Japanese Patent Publication No. 2 9 6 7 3 9 1 and the like. This rotating shaft 1 0 2 is an input shaft 1 2 a and an output shaft 1 0 2 b which are coaxially divided in two in the axial direction, and is inserted into each of the input and output shafts 1 0 2 a and 102 b. Each of the shafts 102a, 102b and a torsion bar 102c combined with spline at both ends, and the springs 1 1 1 that spring the above-mentioned input and output shafts 102a, 102b toward each other in the axial direction are The main composition. A slider 921 having a convex cam portion 921a on the end face of the large-diameter portion of the input shaft 102a is coupled by a bolt-groove coupling to allow sliding in the axial direction. On the input shaft 1 02a, a ball cup 924 engaging end of the displacement detection lever 152 -6-(2) (2) 200307123 supported by a pin 153 is swingably supported in the center of the displacement detection he rod end 152 is coupled with a stroke sensor (str 〇kesens 〇r) stroke detecting shaft 150 of 151. The ball cup 924 is often pressed against the output shaft 1 〇2b by a coil spring 199, so the ball cup 924 is often pressed against the output shaft 〇2b while absorbing its rotation. . Two concave cam grooves 922 engaged with the convex cam portion 9 2 1 a of the slider 9 2 1 on the end surface of the output shaft 10 2 b are formed in the circumferential direction. The small-diameter gear teeth 113 formed in the small-diameter portion of the input shaft 102a are input with a pedaling force. The gear teeth 102e of the input shaft 102a are inputted with an auxiliary input by a drive motor (not shown). A gear 102d connected to a small-diameter portion of the input shaft 10 2 a is engaged with an output sprocket shaft (not shown). In this configuration, when the torsion bar 102c is twisted in accordance with the pedaling force, a phase difference in the rotation direction occurs between the input shaft 102a and the output shaft 102b, and a phase difference also occurs between the output shaft 102b and the slider 921. If the phase difference ball cup 924 is displaced in the axial direction based on this, the displacement detection lever 1 52 will swing about the pin 1 53 as an axis, so the swing is transmitted to the stroke sensor 150 and detected. SUMMARY OF THE INVENTION The above-mentioned conventional torque detection mechanism is complicated in structure due to the large number of parts, which easily leads to an increase in the size of the device or a complicated process. In addition, since there are many sliding positions or docking positions, it is necessary to use a material having excellent abrasion resistance or durability. An object of the present invention is to provide a pedaling force detection device capable of solving the problems of the above-mentioned conventional technology, a structure with a small number of parts (3), (3) 200307123, a simple and small size, a small sliding position or abutting position, and a good torque detection. In order to achieve the above object, the present invention is a pedaling force detecting device for an electric assisted bicycle. The twist amount of the torsion bar is detected, and it is characterized in that the following measures are taken. (1) It is characterized by comprising a pair of magnet rings arranged on one end side and the other end side of the torsion bar, magnetized at a slight pitch along the circumferential direction, and a magnetic sensor sensing the magnetic body, A support means for elastically contacting the magnetic sensor with a pair of magnet rings. (2) A pair of magnet rings disposed on one end side and the other end side of the torque rod and magnetized at a slight pitch along the circumferential direction, and a magnetic sensor that senses the magnetic body, A supporting means that is provided with a docking portion that elastically abuts a predetermined mated body, and elastically brings the magnetic sensor into contact with a magnet ring. (3) A pair of magnet rings arranged on one end side and the other end side of the torsion bar and magnetized at a slight pitch along the circumferential direction, and a magnetic sensor including a magnetic sensor And a fixing means for maintaining the magnetic sensor unit in a predetermined gap with the magnetic sensor and the magnetic ring to face the magnetic sensor unit. According to the above feature (1), since the magnetic sensor can be elastically contacted to the magnet ring, the relative positional relationship between the magnetic sensor and the magnet ring can be kept constant even if the crank shaft is eccentric. -8- (4) (4) 200307123 In accordance with the above feature (2), if the abutment part of the supporting means is abutted against a magnet ring or an eccentric mated body that is eccentric with the magnet ring, if the crank shaft is eccentric, according to Since this magnetic sensor is also displaced in the same manner, the relative positional relationship between the magnetic sensor and the magnet ring can be kept constant even if the crank shaft is eccentric. According to the above feature (3), since the magnetic sensor is firmly fixed to the vehicle body frame, the positional relationship between the magnetic sensor and the magnet ring can always be kept constant. [Embodiment] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of an electric assist bicycle equipped with a pedaling force sensor of the present invention. The electric assist bicycle 1 is a foldable type, and the body frame 4 is foldable at a substantially central portion in the front-rear direction of the vehicle body. 2 is composed of the rear frame 3, and each frame 2 and 3 are connected by the connection part 10. A head pipe 5 is disposed at the front end of the front frame 2. The head pipe 5 is equipped with a front wheel 7 and a front fork 6 of a handle 8 to support the steering freely. A thin plate support frame 11 extending obliquely upwards and backwards is coupled to the front end of the rear frame 3, and a sheet post mounting portion 11a arranged at the rear end portion of the thin plate support frame 11 is mounted to move up and down freely. A thin plate pillar 13 is further provided with a saddle 14 on the thin plate pillar 13. A thin-plate column height adjusting rod 12 is arranged in the thin-plate column mounting portion 11 a. The rear frame 3 -9- (5) (5) 200307123 is pivotally supported by a rear wheel 15 at a rear end thereof, and a crank unit 50 (described later) is mounted below. A handle 8a is disposed at the handle 8 described above. And the brake lever 8b is provided with a front brake 17 and a rear brake 18 respectively at the front and rear of the vehicle body. On the rear wheels: [5] The hub (6) of the motor (16) as an auxiliary power source is arranged on the coaxial. The motor 16 is preferably a three-phase brushless motor with high torque and low friction. A crank 21 coupled to a pedal 24 is coupled to a crank shaft 23. The crank shaft 23 is coupled to a pedal sprocket 25 via a pedal force sensor (s en s 0 r) described later, and the pedaling force applied to the pedal 24 is transmitted to the pedal sprocket 25 via the pedal force sensor. The pedal sprocket 25 is coupled to a driven sprocket (not shown) of the rear wheel via a chain 27. A battery 9 serving as a power source for the motor 16 and the like is housed in the center of the vehicle body. Fig. 2 is a diagram schematically showing the power transmission mechanism of the electric assist bicycle, and the same reference numerals denote the same or equivalent parts. The pedaling force input from the pedal 24 is input to the driven sprocket 26 of the rear wheel 15 through the crankshaft 23, the pedal sprocket 25, and the chain 27. After being decelerated by the gear mechanism of the transmission 30, it is generated by the motor 16 Auxiliary power synthesis to drive the rear wheels 15. FIG. 3 is a cross-sectional view of the motor 16, and a cylinder 30 assembling the transmission is supported by the shaft 31. A wheel hub 32 is fitted to the periphery of the cylinder 30. The hub 32 is an annular body having an inner cylinder and an outer cylinder. The inner periphery of the inner cylinder faces the periphery of the cylinder 30. The connecting plate 33 protruding from the cylinder 30 on the side of the hub 32 is fixed with a bolt 34. On the inner periphery of the outer tube of the hub 32, the ammonium magnets constituting the rotor-side magnetic poles of the motor 16 are arranged at predetermined intervals. That is, the outer cylinder is a rotor core constituting a holding magnet 35. A bearing 36 is fitted to the periphery of the inner cylinder of the hub 32, and a stator support plate 37 is fitted to the periphery of the bearing 36. A stator 38 is arranged on the periphery of the stator support plate 37 and is attached by bolts 40. The stator 38 is disposed so as to have a predetermined gap from the outer cylinder of the rotor core, that is, the hub 32, and the stator 38 is wound with a three-phase coil 39. A magnetic pole sensor 41 made of a Hall element is arranged on the side of the stator support plate 37. The magnetic pole sensor 41 senses a change in magnetic flux when the magnet 4 2 protrudingly arranged from the hub 3 2 passes, and outputs a position signal of the hub 32 as a rotor. The magnetic pole sensor 41 is arranged at three positions corresponding to each phase of the motor 16. A control board 43 for controlling the energization of the three-phase coils 39 by a position signal from the magnetic pole sensor 41 is provided on the side of the stator support plate 37. A CPU is mounted on the control board 43 Or FET control elements. The control board 43 may be integrated with the mounting board for the magnetic pole sensor 41 described above. A spoke 44 connected to a rim (not shown) of a rear wheel (not shown) is fixed to the periphery of the hub 32. In addition, a bracket 46 is fixed to the stator support plate 37 on the opposite side to the side on which the control board 43 and the like are mounted by bolts 45. The bracket 46 is on a plate 29 of the vehicle body frame 4. They are connected by bolts (not shown). Fig. 4 is a side sectional view of a crank unit 50 mounted on the lower portion of the frame, and a pedaling force detecting device 500 is mounted on the crank portion. Figure 5 is a cross-sectional view along the crank axis of -11-(7) (7) 200307123. As shown in Fig. 4, the crank unit 50 is fixed to the lower portion of the frame at three positions with screws. In the crank unit 50, as shown in Fig. 5, one end of the crank shaft 23 is rotatably supported by a bearing 51. A cylindrical torsion bar 5 3 is inserted through the periphery of the crank shaft 23. One end of the crank shaft 23 is bolted to the outer surface of the crank shaft 23 in the vicinity of the bearing 5 1, and the other end is connected to the crank unit 5 0 through the bearing 5 2. It is rotatably supported by a shaft. The pedal sprocket 25 is engaged with the outer peripheral surface of the other end side of the crank shaft 23. A pair of magnet rings 55 (5 5a, 5 5b) are provided along the circumferential direction on the outer side surfaces of the torsion bar 5 3 near one end side and near the other end side. The magnet ring 55 is formed by magnetizing at a small pitch in the circumferential direction. A pair of MR sensors 5 0 1 (50 1 a, 50 1 b) are arranged at positions facing the magnet ring 55. Fig. 6 is a cross-sectional view showing an example of the mounting structure of the MR sensor 501. The MR sensor 501 is mounted on one main surface of the sensor substrate 502. The detection signal of the MR sensor 501 is led to the outside through a harness 503. The aforementioned sensor substrate 5 0 2 is fixed to one end of a slightly L-shaped leaf spring 5 0 6. The other end of the L-shaped leaf spring 5 0 6 is such that the MR sensor 5 0 1 is elastically contacted to the magnet ring 5 5 by the elastic force of the leaf spring 5 0 6 and is fixed to the crank unit by a screw 5 0 5 5 0 underside. According to this sensor mounting structure, the MR sensor 5 0 1 can be elastically contacted with the magnet ring 5 5. Therefore, even if the crank shaft 2 3 is eccentric, the MR sensor 5 0 1 and the magnet ring can be kept constantly. The relative position of 5 5 depends on -12- (8) (8) 200307123. Therefore, regardless of the eccentricity of the crank shaft 23, it is possible to accurately detect the pedaling force represented by the amount of torsion of the torsion bar 5 3 with a simple structure. Fig. 7 is a cross-sectional view showing another example of the mounting structure of the MR sensor 501. The sensor substrate 502 is fixed to one end of a slightly L-shaped leaf spring 507. The other end of the aforementioned L-shaped leaf spring 507 is fixed to one side (508a) of a pair of clamps 508 that are engaged with each other by screws 509. The aforementioned pair of clamps 508 are spring-opened to each other via a coil spring 510 to be engaged. The other side (508b) of the pair of holders 508 is such that one side (508a) elastically abuts at a predetermined position of the magnet ring 55, and is fixed to the bottom surface of the crank unit 50 by screws 505. The MR sensor 501 and the holder 508 are in a state where one of the holders 508a is abutted to a predetermined position of the magnet ring 55, and the MR sensor 501 is elastically contacted with the magnet ring 5 5 other predetermined positions, while being relatively positioned in advance. According to this sensor mounting structure, if the crank shaft 23 is eccentrically clamped by 5 8 a, the MR sensor 5 0 1 is also displaced accordingly. Therefore, even if the crank shaft 23 is eccentric, the MR can be made MR. The sensor 5 0 1 pair of magnet rings 5 5 are often positioned correctly. Fig. 8 is a cross-sectional view showing still another example of the mounting structure of the MR sensor 501. The sensor substrate 50 is fixed to one end of a leaf spring 511. A zigzag spring portion 5 1 1 a is formed at the other end of the leaf spring 5 1 1, and a pair of clamps 5 i 2 (5 丨 2a, 51 2b) which can be slidably combined with each other has its elasticity. The force urges one clamper 512a to the other clamper 5 1 2 b in the direction of the crank to be stored. Other clamps -13- (9) 200307123 The tool 5 12b elastically abuts the abutment portion of one clamper 512a with the magnet ring 55 at a predetermined position and is fixed to the bottom surface of the crank unit by screws 5 05. The MR sensor 5 0 1 and the holder 5 1 2 are in a state where one of the holders 5 12 a is abutted to a predetermined position of the magnet ring 55, and the MR sensor 5 0 1 elastically contacts the other of the magnet ring 5 5. Predetermined position, while being positioned on the ground in advance. If a coil spring is not prepared separately according to this embodiment, the same effect as that of the mounting structure of Fig. 7 can be obtained. In addition, although the mounting structure shown in FIG. 7 uses the one side of the holder to connect the magnet ring, it is connected to the crank shaft 23 or the torsion bar 5 3 and others that are eccentric to the magnet ring 5 5. Body can also. Fig. 9 is a diagram showing another example of the mounting structure of the MR sensor 501. The sensor substrate 502 is fixed to one end of a slightly L-shaped clamp 504. The other end of the aforementioned L-shaped holder 504 keeps the gap between the MR sensor 5 0 1 and the magnet ring 5 5 at a predetermined value (for example, 50 μm and is fixed to the crank unit 5 0 by screws 5 0 5 Bottom surface. According to this sensor mounting structure, the MR sensor 501 can be brought into non-contact with the magnet ring 55, so the durability of the MR sensor 501 and the magnet 55 is improved. Figure 10 shows the display In the block diagram of the configuration of the main part of the pedaling force detection circuit in the embodiment, two variable resistors R 1 and R 2 that change in accordance with the magnetic resistance 値 are connected in series to each MR sensor 501. Each MR sensor The output signals of the device 5 0 1 a (50 0 1 b) are 50 pieces of equipment V1, V2 and 8 are the same as the measurement.) The device ring must be according to -14- (10) 200307123 occurred in the aforementioned torque rod 5 3 If it is twisted, as shown in FIG. 12, the initial phase difference of Wakazen is caused only by the deviation generated during manufacturing and assembly. In contrast, if the torsion bar 53 is twisted, the initial phase difference 0 ref is added to each of the output signals VI and V2 as shown in Fig. 13 to generate the phase difference 0 F according to the torsion amount of the torsion bar 5 3. In this embodiment, in order to quantitatively detect the phase (9 F, each MR sensor 5 0 1 a (50 0 1 b)) representing the pedaling force, the output signal V 1 (via a high-pass filter ( HP F) 2 0 2a (), limit amplifier (203a (203b)), a comparison circuit (comparator) 204a (204b) for shaping, to a CPU 205 with a counter. The CPU 205 is as follows: Shows the delay time η of the count output signal V2 to the output signal V 1. The period N of the output signal V 1 is obtained by the following formula (1): phase difference 0 phase difference 0 F = n / N. 3 60 [degrees] -0 ref ... (1) Here, the phase difference and pedaling force show linearity as shown in Fig. 14. Therefore, if the phase difference 0 F can be detected, it can be obtained only by putting the phase difference 0 into a simple proportional equation. Fig. 11 is a block diagram showing the structure of a portion of another embodiment of the pedaling force detection circuit. Four variable resistors R 1 to R 4 connected to each of the MR sensors 501 in accordance with the magnetic force 成 are connected to form a block diagram. Two bridges are in inverse phase. Noise can be captured if this bridge circuit is used, so the pedaling force can be obtained more accurately. Efficacy of the invention] The generation of the difference between the Θ ref graph and the production level difference V2) 202b and the wave input 15 graph and the special resistance of the F F generation of the main resistance output are reduced-15- (11) (11) 200307123 The following effects: (1) According to the inventions in the scope of claims 1 and 2 of the patent application, the magnetic ring can be elastically brought into contact with the magnetic ring, so even if the crank shaft is eccentric, the magnetic sensor can always be maintained. The relative position of the sensor and the magnetic ring is related to -g 〇 (2). If according to the inventions in the scope of patent application Nos. 3, 4, 5, and 6, if the crank shaft is eccentric, the magnetic sensor will be the same. Ground displacement, so even if the crank shaft is eccentric, the relative positional relationship between the magnetic sensor and the magnet ring can always be kept constant. (3) If the invention according to item 7 of the scope of the patent application is applied, the magnetic sensor will affect the car. The body frame is firmly fixed, so the positional relationship between the magnetic sensor and the magnet ring can always be maintained. [Brief description of the drawings] 'The first figure is an electric assist bicycle equipped with a pedaling force sensor of the present invention. Side view Figure 2 is a pattern ground A diagram showing a power transmission mechanism of an electric assist bicycle. Fig. 3 is a cross-sectional view of a drive motor. Fig. 4 is a side view of a crank unit. Fig. 5 is a cross-sectional view along a crank axis of the crank unit. Fig. 7 shows an example of the mounting structure of the MR sensor (Part 1). Fig. 7 is a diagram showing an example of the mounting structure of the MR sensor (Part 2) -16- (12) 200307123. FIG. 8 is a diagram showing an example (part 3) of the mounting structure of the MR sensor. FIG. 9 is a diagram showing an example (part 4) of a mounting structure of the MR sensor. Figure 10 is a block diagram of the main part of the pedaling force detection circuit (part one) °
第11圖是踏力檢測電路的主要部位的方塊圖（其二 )° 第1 2圖是第1 0圖的主要部位的訊號波形圖（無踏力 )° 第1 3圖是第i 0圖的主要部位的訊號波形圖（有踏力 )° 第1 4圖是顯示第i 〇圖中的相位差與踏力的關係圖。 第1 5圖是顯示相位差的求法的圖。Figure 11 is a block diagram of the main part of the pedaling force detection circuit (second) ° Figure 12 is a signal waveform diagram of the main part of Figure 10 (without pedaling force) ° Figure 13 is the main part of Figure i 0 The signal waveform of the part (with pedaling force) ° Figure 14 is a graph showing the relationship between the phase difference and the pedaling force in the i 0th figure. Fig. 15 is a diagram showing how to obtain a phase difference.
第1 6圖是習知的輔助自行車所使用的踏力檢測機構 白勺主要部位的剖面圖。 [符號說明〕 1 :電動輔助自行車 2:前框架 3:後框架 5：頭管 6:前叉 -17- (13) (13)200307123 7：前輪 8:把手 1 1 :薄板支持框架 1 1 a :薄板柱安裝部 1 2 :薄板柱高度調整用桿 1 3 :薄板柱 14:車座 1 5 後輪 1 6 :馬達 1 7 :前煞車 1 8 :後煞車 2 3 :曲柄軸 2 4 :踏板 2 5 :踏板鏈輪 26:從動鏈輪 2 7 :鏈條 3 〇 :汽缸 3 1 :軸 3 2 :輪轂 3 3 :連結板 34 > 40:螺栓 3 5 :磁石 3 6 : 軸承 3 7 :定子支持板 -18 (14) (14)200307123 38:定子 3 9 :三相線圈 4 1 :磁極感測器 4 2 :磁石 43:控制基板 44:輪幅 4 5 :螺栓 46:托架 5 0 :曲柄單元 5 1、5 2 : 軸承 5 3、1 0 2 c : 扭力棒 55、55a、55b:磁鐵環 1 0 2 a :輸入軸 102b:輸出軸 1 0 2 e :齒輪齒 1 5 0 :衝程感測器 1 5 2 :位移檢測桿 1 5 3 :銷 199:螺旋彈簧 202a、202b:高通濾波器 2 0 3 a ^ 2 0 3 b:限幅放大器Fig. 16 is a cross-sectional view of a main part of a pedaling force detecting mechanism used in a conventional assist bicycle. [Symbol description] 1: Electric-assisted bicycle 2: Front frame 3: Rear frame 5: Head tube 6: Front fork -17- (13) (13) 200307123 7: Front wheel 8: Handle 1 1: Sheet support frame 1 1 a : Sheet post mounting section 1 2: Sheet post height adjustment lever 1 3: Sheet post 14: Seat 1 5 Rear wheel 1 6: Motor 1 7: Front brake 1 8: Rear brake 2 3: Crank shaft 2 4: Pedal 2 5: Pedal sprocket 26: Driven sprocket 2 7: Chain 3 〇: Cylinder 3 1: Shaft 3 2: Hub 3 3: Connecting plate 34 > 40: Bolt 3 5: Magnet 3 6: Bearing 3 7: Stator Support plate-18 (14) (14) 200307123 38: Stator 3 9: Three-phase coil 4 1: Magnetic pole sensor 4 2: Magnet 43: Control board 44: Spoke 4 5: Bolt 46: Bracket 5 0: Crank unit 5 1, 5 2: Bearing 5 3, 1 0 2 c: Torque bars 55, 55a, 55b: Magnet ring 1 0 2 a: Input shaft 102b: Output shaft 1 0 2 e: Gear teeth 1 5 0: Stroke Sensor 1 5 2: Displacement detection lever 1 5 3: Pin 199: Coil spring 202a, 202b: High-pass filter 2 0 3 a ^ 2 0 3 b: Limiting amplifier
2 0 4 a、2 0 4 b ·.波形整形用的比較電路 20 5: CPU 5 00:踏力檢測裝置 -19- (15) (15)200307123 501、501a、501b: MR 感測器 5 02:感測器基板 503:裝具 5 0 6、5 0 7、5 1 1 :板彈簧 504、 508、 508a、 508b、 512:夾持具 5 00:踏力檢測裝置 5 0 9 :螺絲 5 1 〇 :螺旋彈簧 5 11a:鋸齒形彈簧部 9 2 1 : 滑塊 921a: 凸凸輪部 9 2 4 : 球杯 -20-2 0 4 a, 2 0 4 b · Comparison circuit for waveform shaping 20 5: CPU 5 00: Pedal force detection device-19- (15) (15) 200307123 501, 501a, 501b: MR sensor 5 02: Sensor substrate 503: Mounting device 5 0 6, 5 0 7, 5 1 1: Leaf spring 504, 508, 508a, 508b, 512: Clamping device 5 00: Pedal force detection device 5 0 9: Screw 5 1 〇: Coil spring 5 11a: Serrated spring portion 9 2 1: Slider 921a: Convex cam portion 9 2 4: Ball cup -20-