200836971 、 九、發明說明： 【發明所屬之技術領域】 本發明係關於自行車用前變速系統。 【先前技術】 前後部設有多段齒輪之自行車已相當普遍，一般多係在 前部設置2片或3片齒輪，而在後部設置5片至1 0片的齒 輪。 並於前後部分別具有外裝變速器，且構成爲藉由使該外 裝變速器朝自行車之車寬方向移動而換掛上鏈條，而可選 擇所需之齒輪比，在前變速器中，在自行車之車寬方向上 大致平行地設有2片板，利用該些板按壓鏈條而使其移動。 又，最近之自行車幾乎都採用分檔（index)系統，且藉由 鋼索調整而設定成最佳之變速點。 【發明內容】 (發明所欲解決之課題） , 然而，在前變速器之情況，因爲藉由朝自行車之車寬方 向移動而強制性地移動鏈條，所以，在有力矩施加於鏈條 上之情況，使得平滑地變速顯得非常難。 如第1圖所示，在前側組裝有具備換掛鏈條6用之外板 4a及內板4b之前變速器4，在此雖未圖示，但其構成爲藉 由變速撥桿對鋼索之牽引及開放，以使前變速器朝自行車 之車寬方向移動，而可將鏈條換掛於所需之齒·輪上，更詳 細而画’在欲從小徑齒輪2 c側朝大徑齒輪2 a側（以下稱爲 向上變檔）（up shi ft)換掛鏈條之情況，藉由鋼索之牽引以使 200836971 • 外板4a及內板4b朝大徑齒輪2a側移動，藉由內板4b按 壓鏈條而使鏈條朝大徑齒輪2 a側移動，以換掛於所需之齒 輪上。 另外，在欲從大徑齒輪2 a側朝小徑齒輪2 c側（以下稱爲 向上變檔）換掛鏈條之情況，當鋼索被開放時，藉由內建於 前變速器之恢復彈簧4 c，以使外板4 a及內板4 b朝小徑齒 輪2c側移動，藉由外板4a按壓而使鏈條朝小徑齒輪2c側 移動，以換掛於所需之齒輪上。 在後側組裝有具備用於換掛鍵條6之外板5 a及內板5 b 之後變速器5，在此雖未圖示，但其構成爲藉由變速撥桿 對鋼索之牽引及開放，以使後變速器朝自行車之車寬方向 移動，而可將鏈條換掛於所需之齒輪上，更詳細而言，在 欲從小徑齒輪3 d側朝大徑齒輪3 a側換掛鏈條之情況，藉 由鋼索之牽引以使外板5 a及內板5b朝大徑齒輪側移動， 藉由外板5 a按壓鏈條而朝大徑齒輪側移動，以換掛於所需 之齒輪上。 % 另外，在欲從大徑齒輪側朝小徑齒輪側換掛鏈條之情 況，當鋼索被開放時，藉由內建於後變速器之恢復彈簧5 c， 以使外板5a及內板5b朝小徑齒輪側移動，藉由內板5b按 壓而使鏈條朝小徑齒輪側移動，以換掛於所需之齒輪上。 根據路況及體力之狀態等，雖如上述藉由變速撥桿操作 外裝變速器以選擇所需的齒輪比，但在進行變速之情況， 必須使鏈輪旋轉，此時在未施加大負載於鏈輪時，並無太 大的問題’而可較爲平滑地變速，但在爬坡路等之情況， 200836971 • 造成大負載施加於鏈輪及鏈條上，在前側，尤其是在向上 變檔時，將變得非常難以變速。 另外，雖然最近之鏈輪的齒形被施以改良使其變速性比 以前更佳，但在大負載時其性能依舊不夠充分，而迫切要 求一種更高性能之前變速系統，但若過於追求高性能而作 成極端之齒形時，因爲鏈條之自動變速或鏈條對齒輪的掛 合不良的緣故，而會產生異音或鏈條與齒輪之間的接觸 音、鏈條與外板或內板之間的接觸音等各式各樣的問題。 針對該問題更詳細地說明，一般之齒形係作成如第6圖 所示之形狀，在向上變檔之情況，藉由離脫導引齒2 a a c以 使鏈條朝小徑齒輪側傾斜，並藉由離脫齒2abb以使鏈條自 大徑齒輪脫離，但在該情況時，如第2圖所示，在鏈條繞 掛於後部多段齒輪之大徑齒輪側3 a，3 b，3 c時，係設計成鏈 條不會自前側之大徑齒輪2 a或中徑齒輪2 b自動進行向上 變檔之程度、或不會因鏈條對於齒輪之掛合不良而產生異 音之程度。 、 離脫導引齒2 a a c係朝自行車之車寬方向外側被施以尺寸 P之倒角，離脫齒2abb係朝自行車之車寬方向內側被施以 尺寸q之倒角’在離脫導引輔助齒2acb上施以尺寸〇之倒 角，用以輔助離脫導引齒2aac而使鏈條傾斜。 爲了在大負載時用以提高向上變檔之變速性，如第7圖 所示，雖可切割成如離脫導引齒2aaa狀，以增大離脫齒2aba 之自行車車寬方向內側的倒角，但如圖示，若過於極端的 話，在由於大振動等而使鏈條搖動時、或鏈條之路徑如第 200836971 ^ 2圖所示傾斜之狀態時，即使未進行變速操作，亦即、即 使未使前變速器移動，仍有鏈條自動地朝小徑齒輪側進行 變速、或即使未變速仍因與齒輪之嚙合不良而產生異音的 問題。 另外，爲了提高自小徑齒輪2c朝中徑齒輪2b、自中徑齒 輪2b朝大徑齒輪2a之變速性，如第9圖所示，在大徑齒 輪及中徑齒輪的小徑齒輪側側面，設置在變速時暫時保持 鏈條之突起8 a，8 b，且以儘可能使其朝小徑齒輪側突出爲較 佳，但若太過突出，在由於振動等而使鏈條搖動時、或鏈 條之路徑爲如第3圖所示之狀態時，會有鏈條與突出部接 觸而產生異音的情況。 又，因爲最近之自行車幾乎都採用分檔系統，而必須經 常在已決定之位置進行變速，所以更難以進行平滑之變速。 另外，在分檔系統之情況，雖藉由鋼索調整而設定成最 佳之變速點，但如前述，在力矩施加於鏈條時，在該設定 之分檔點中，難以獲得平滑之變速，使得鋼索調整亦成爲 i 一種麻煩的事。 另外’如日本特開平6 - 3 05 47 5號，雖提出一種藉由前變 速器之改良以提高變速性之方案，但在該情況時，向上變 檔之變速性雖略有改善，但仍無法預期在大負載時有大幅 的改善，另外，向上變檔則完全沒有改善。 再略微詳細地說明時，日本特開平6 - 3 0 5 4 7 5號之目的係 在如第2圖所示之狀態時，用以緩和鏈條與內板間之干涉 音’而其向上變檔之變速性能與習知構造無太大之差異。 200836971 因爲其與鏈條之接觸音有所緩和，所以雖可超越齒盤（〇 v e r shi ft)以提高變速性能，但若如此做的話，反而會造成向上 變檔之性能極度地降低，所以，結果還是無法超越齒盤， 與習知構造比較仍無法大幅提高變速性能。 本發明係用以一舉解決上述課題者，其提供一種即使在 力矩施加於鏈條時，亦可確實地獲得平滑之變速，另外’ 亦可簡單地進行分檔調整之自行車用前變速系統。 (解決課題之手段） 爲達成上述目的，在本發明中，係將除了至少由二片以 上之齒輪構成的前鏈輪的最小徑齒輪之外的齒輪作成鏈條 可容易自動地向上變檔之形狀，且於前變速器上組裝輔助 板，以使鏈條不會因振動或傾斜而自動向下變檔。 【實施方式】 更具體而言，例如在由3片齒輪構成之前鏈輪的情況， 將最大徑齒輪與中間徑齒輪之一部分或全部設計成鏈條由 於振動或傾斜，即使不使前變速器移動，鏈條仍自動地朝 小徑齒輪側變速、或鏈條與齒輪之嚙合變差而產生異音的 形狀，且在前變速器之自行車車寬之方向內側的板上，以 不會自動地朝小徑齒輪側變速的方式、或不會有鏈條與齒 輪之嚙合變差而產生異音的方式組裝輔助板，以便不產生 鏈條之自動變速或異音。 另外，輔助板係設計成可拆卸，藉以在因磨耗等而減少 了輔助板的效果的情況，可更換成新品，並藉由消音材料 等構成輔助板、或設成消音效果，即可緩和與鏈條之接觸 200836971 ‘ 音。 [實施例] 以下，參照圖面說明本發明之實施例。第1圖爲前後具 有外裝變速器之一般的启行車的圖，第2圖爲鏈條朝小徑 齒輪側自動變速或難以平滑地繞掛於齒輪上之狀態圖，第 3圖爲設於齒輪上之變速用突起與鏈條容易產生接觸音的 狀態圖，第4圖及第5圖爲本發明之實施形態的說明圖， 第6圖爲現狀齒輪之齒形的說明圖，第7圖及第8圖爲容 易自動變速之齒輪之齒形的說明圖，第9圖爲自中徑齒輪 朝大徑齒輪的變速狀態圖，第1 0圖爲由輔助板保持鏈條之 狀態圖，第1 1圖爲鏈條繞掛於前大徑齒輪與後大徑齒輪之 狀態圖，第1 2圖爲鏈條繞掛於前中徑齒輪與後大徑齒輪之 狀態圖。 在本發明中，爲了大幅提高向上變檔之變速性，將離脫 導引齒作成如第7圖之齒2aaa的形狀，並將該離脫導引齒 之後方2至3片離脫齒作成如齒2aba之形狀，以使鏈條更 % 容易朝小徑齒輪側脫離。 離脫導引齒2aaa係將習知齒2aac加以切割者，其目的是 用以使鏈條容易朝更小徑齒輪側傾斜，離脫齒2aba係設置 比習知齒2abb之自行車車寬方向內側的倒角q更大之倒角 t，其目的在即使鏈條僅略微傾斜時亦可脫離，離脫導引輔 助齒2 a c a係設置比習知齒2 a c b之自行車車寬方向外側的倒 角◦更大之倒角1·，其目的在藉由離脫導引齒2 a a a而使鏈 條的傾斜變得更大。 -10- 200836971 • 在另一實施例中，係如第8圖之離脫導引齒2 a a b所示’ 未如離脫導引齒2aaa般進行切割’而係將自行車車寬方向 外側的倒角作成比習知離脫導引齒2aac之倒角p更大之倒 角s，藉以達成讓鏈條容易朝更小徑齒輪側傾斜的目的。 雖在最小徑齒輪以外的齒輪設置此種離脫導引齒、離脫 齒、離脫導引輔助齒之形狀，但在此狀態下，鏈條如第2 圖所示般傾斜時，即使不操作前變速器，鏈條仍會朝小徑 齒輪側自動變速，或會因鏈條對齒輪之繞掛不良而產生異 音。 反之，在如第2圖之狀態時，以鏈條朝小徑齒輪側自動 變速或產生異音的方式，設定離脫導引齒、離脫齒、離脫 導引輔助齒之齒形。 另一方面，在前變速器4之內板4b上，一體或可離脫地 設置輔助板7，且輔助板與內板之自行車車寬方向之位置 關係，係在如第2圖所示之狀態時，設定成內板4b與鏈條 不直接接觸而由輔助板先接觸。這是因爲內板一般是由剛 " 性高之金屬所製成，所以當鏈條接觸於內板時會產生具不 協調感之金屬音，故使內板與鏈條不直接接觸。 更詳細地說明時，因爲在鏈條繞掛於鏈輪之大徑齒輪與 後方自由飛輪之最大徑齒輪時，鏈條與內板4b最容易接觸 之部位係如第1 1圖所示，在點p 1之附近，所以，在其後 方部將輔助板之面7a配置於比點p 1更早與鏈條接觸之位 置，另外，因爲在鏈條繞掛於鏈輪之中徑齒輪與後方自由 飛輪之最大徑齒輪時，鏈條與內板4b最容易接觸之部位係 *11- 200836971 ' 如第1 2圖所示，在點P 2之附近，所以，在其後方部將輔 助板之面7b配置於比點P2更早與鏈條接觸之位置。 在使用組合如上述構成之鏈輪及前變速器之情況，以下 將說明其可發揮何種效果。 如本實施例，當將離脫導引齒、離脫齒、離脫導引輔助 齒作成極端之形狀時，雖可大幅改善向上變檔，但鏈條在 如第2圖之狀態時，即使不使前變速器作動，仍會自動地 向上變檔、或即使不向上變檔，鏈條對齒輪之繞掛仍變差 而產生異音’迨是因爲鏈條係比通常之路徑更增大朝小徑 齒輪側之傾斜，而靠向更小徑齒輪側之緣故。 但是’在本發明之前變速器上’在如第2圖之狀態時， 如第1 0圖所示，因爲將輔助板設成與鏈條接觸或具有微小 間隙，所以即使鏈條欲比通常之路徑更靠近小徑齒輪側 時’仍可藉由該輔助板來保持，所以可維持通常之路徑， 而無自動地向上變檔、或鏈條對齒輪之繞掛變差而產生異 音的情況。 此時，雖因鏈條與輔助板接觸而產生接觸音，但輔助板 係由比一般之金屬材料可緩和與鏈條之接觸音的材料、例 如樹脂等所形成，所以，不會產生感到不適感之聲音，若 進一步使用具有消音效果之樹脂材料、或在內板與輔助板 之間插入具消音效果之阻尼益’則可進一步緩和接觸音。 在本實施例中，輔助板7係藉由銷9而安裝於內板上， 但亦可將輔助板7與內板4b形成爲一體，而於面7a及面 7 b貼上或黏者具消音效果之材料，或亦可由具消音效果之 1 200836971 • 材料來形成內板4 b整體。 照不由 離脫導 前變速 鏈條.， 之情況 之形狀 檔之性 徑齒輪 ，藉由 :示，藉 丨，但如 使突起 示，在 以突出 能，但 4b與鏈 結果， 在自第2圖之狀態而向上變檔之情況，因爲係依 輔助板來保持時自動進行向上變檔之程度，來設定 引齒、離脫齒、離脫導引輔助齒之形狀，所以當使 器朝小徑齒輪側移動時，會變得不由輔助板來保持 而使鏈條瞬間轉掛於小徑齒輪側。 另外，即使在鏈條繞掛於後方自由飛輪之齒輪3 d 時’仍可將離脫導引齒、離脫齒、離脫導引輔助齒 作成鏈條容易脫離之形狀，所以可大幅提高向上變 會b 。 在向上變檔中，在習知構造之情況，例如在自中 朝大徑齒輪變速時，使前變速器朝大徑齒輪側移動 內板4b將鏈條朝大徑齒輪側頂壓，其後如第9圖戶ϋ 由突起8 a而頂起鏈條，而使鏈條移動至大徑齒輪俱I. 前述，因爲在施加大負載時其變速困難，所以雖然 8 a處在朝小徑齒輪側更爲突出之處，但如第3圖所 % 鏈條傾斜時，因爲鏈條與突起接觸而產生異音，所 高度受到限制，另外，雖藉由超越齒盤亦可提高性 在該情況時，因爲在變速結束後，前變速器之內板 條接觸而產生異音，所以亦無法進行超越齒盤，其 現狀是無法獲得充分之變速性能。 但是，在本發明中，輔助板7係比內板及鏈條之接觸更 早進行接觸，所以，即使在超越齒盤而變速之後，仍不會 產生如金屬音之異音，所以，可充分地超越齒盤，其結果 200836971 即使施加大負載仍可大幅提高自小徑齒輪側朝大徑齒輪側 之變速性能。 如前述’在本發明中，因爲將大徑齒輪及中徑齒輪之齒 形作成容易自動變速之形狀，以大幅提高向上變檔之變速 性能，所以，即使稍有超越齒盤，仍不會降低向上變檔之 變速性能，其結果，可同時大幅提高向上變檔及向上變檔 的變速性能。 又，本發明並不限於本實施例，在前鏈輪中，在鏈條相 對於齒輪傾斜的情況，可作成自動變速之齒形，另外，在 前變速器中，在鏈條相對於齒輪傾斜的情況，在鏈條接觸 於輔助板時，若不產生具有不適感之接觸音即可。 (發明效果） 在習知之前變速系統中，雖對前鏈輪形狀的齒形或前變 速器加以改良以提高其變速性能，但若欲極端地提高變速 性能時，則會產生自動變速或異音，所以該改良仍有界限， 現狀是在高負載時無法獲得充分的變速性能，另外藉由分 檔系統之普遍化，在可滿足向上變檔及向上變檔之任一方 的點進行調整非常麻煩，其結果，不得不在某種程度之性 能上作妥協。 本發明係用以一舉解決現狀之問題點，藉由將除了前鏈 輪之小徑齒輪之外之齒輪的齒形作成可自動變速的形狀， 同時於前變速器設置輔助板，以保持鏈條不會自動變速， 可大幅提高在高負載時之向上變檔的變速性能，且藉由設 置輔助板及大幅提高向上變檔的變速性能，可使前變速器 -14- 200836971 - 超越齒盤，所以亦可大幅提高向上變檔之變速性能，藉由 使用組合本發明之前鏈輪及前變速器，可獲得迄今爲止所 沒有之巨大效果。 【圖式簡單說明】 第1圖爲前後具有外裝變速器之一般的自行車的圖。 第2圖爲鏈條朝小徑齒輪側自動變速或難以平滑地繞掛 於齒輪上之狀態圖。 第3圖爲設於齒輪上之變速用突起與鏈條容易產生接觸 f 音的狀態圖。 第4圖爲本發明之實施形態的說明圖。 第5圖爲本發明之實施形態的說明圖。 第6圖爲現狀齒輪之齒形的說明圖 第7圖爲容易自動變速之齒輪之齒形的說明圖。 第8圖爲容易自動變速之齒輪之齒形的說明圖。 第9圖爲自中徑齒輪朝大徑齒輪的變速狀態圖。 第1 0圖爲由輔助板保持鏈條之狀態圖。 % 第11圖爲鏈條繞掛於前大徑齒輪與後大徑齒輪之狀態 圖。 第1 2圖爲鏈條繞掛於前中徑齒輪與後大徑齒輪之狀態 圖。 【主要元件符號說明】 2 a a a 離脫導引齒 2 a a b 離脫導引齒 2 a a c 離脫導引齒 -15- 200836971 2 a b a 離 脫 齒 2 ab b 離 脫 齒 2 a c a 離 脫 導 引 輔 助 齒 2 a c b 離 脫 導 引 輔 助 齒 Q 倒 角 T 倒 角 〇 倒 角 R 倒 角 P 倒 角 S 倒 角 2a 大 徑 齒 輪 2b 中 徑 齒 輪 2 c 小 徑 齒 輪 3 a , 3 b , 3 c 大 徑 齒 輪 3d 小 徑 齒 輪 4 刖 變 速 器 4 a 外 板 4b 內 板 4 c 恢 復 彈 簧 5 後 變 速 器 5 a 外 板 5b 內 板 5 c 恢 復 彈 簧 6 鏈 條 -16 200836971 7 輔助板 7a, 7b 輔助板之面 8a,8b 突起 9 銷200836971, IX. Description of the Invention: [Technical Field of the Invention] The present invention relates to a bicycle front shifting system. [Prior Art] A bicycle having a plurality of gears at the front and the rear is quite common, and generally two or three gears are provided at the front, and five to ten gears are provided at the rear. And having an external transmission in the front and rear portions, respectively, and configured to change the hanging gear by moving the externally mounted transmission toward the width direction of the bicycle, and selecting a desired gear ratio in the front derailleur, in the bicycle Two plates are provided substantially in parallel in the vehicle width direction, and the chains are pressed by the plates to move them. Also, most recent bicycles have adopted an index system and are set to an optimum shift point by wire adjustment. [Problem to be Solved by the Invention] However, in the case of the front derailleur, since the chain is forcibly moved by moving toward the vehicle width direction of the bicycle, when a moment is applied to the chain, Making smooth shifting is very difficult. As shown in Fig. 1, the transmission 4 is provided on the front side with the outer plate 4a for replacing the chain 6 and the inner plate 4b. Although not shown, it is configured to be pulled by the shift lever and the cable. Open, so that the front derailleur can move toward the width of the bicycle, and the chain can be changed to the required tooth and wheel. In more detail, the picture is drawn from the small diameter gear 2 c side toward the large diameter gear 2 a side ( In the case of the upshifting of the chain (up shi ft), the traction of the steel cable causes the 200836971 • the outer panel 4a and the inner panel 4b to move toward the large-diameter gear 2a side, and the inner panel 4b presses the chain. The chain is moved toward the large diameter gear 2 a side to be hung on the desired gear. Further, in the case where the chain is to be changed from the side of the large-diameter gear 2a toward the side of the small-diameter gear 2c (hereinafter referred to as the upward shift), when the cable is opened, the return spring 4c built in the front derailleur is used. The outer plate 4a and the inner plate 4b are moved toward the small-diameter gear 2c side, and the outer plate 4a is pressed to move the chain toward the small-diameter gear 2c side to be attached to the desired gear. The transmission 5 is provided on the rear side with the outer plate 5 a and the inner plate 5 b for replacing the key strip 6 . Although not shown, it is configured to pull and open the cable by the shift lever. In order to move the rear derailleur toward the width direction of the bicycle, the chain can be changed to the required gear, and more specifically, the chain is to be changed from the small diameter gear 3 d side toward the large diameter gear 3 a side. The outer plate 5a and the inner plate 5b are moved toward the large-diameter gear side by the pulling of the steel wire, and the chain is pressed by the outer plate 5a to move toward the large-diameter gear side to be attached to the desired gear. In addition, in the case where the chain is to be changed from the side of the large-diameter gear toward the side of the small-diameter gear, when the cable is opened, the return spring 5c built in the rear derailleur is used to cause the outer panel 5a and the inner panel 5b to face The small-diameter gear side moves, and the chain is moved toward the small-diameter gear side by the inner plate 5b to be pressed to the desired gear. Depending on the condition of the road and the state of the physical force, etc., the external gearbox is operated by the shift lever as described above to select the desired gear ratio. However, in the case of shifting, the sprocket must be rotated, and at this time, no large load is applied to the chain. There is not much problem when it is rounded, and it can be shifted more smoothly, but in the case of climbing, etc., 200836971 • Causes a large load to be applied to the sprocket and the chain, on the front side, especially when shifting upwards. Will become very difficult to change speed. In addition, although the tooth profile of the recent sprocket has been modified to make it more versatile than before, its performance is still insufficient at large loads, and a higher performance prior shifting system is urgently required, but if it is too high When the performance is made into an extreme tooth shape, the contact between the chain and the gear, the contact between the chain and the outer or inner plate may occur due to the automatic shifting of the chain or the poor connection of the chain to the gear. Sounds and other various problems. To explain the problem in more detail, the general tooth shape is formed into a shape as shown in Fig. 6, and in the case of upward shifting, the chain is tilted toward the small-diameter gear side by the off-guide tooth 2 aac, and By disengaging the teeth 2abb to disengage the chain from the large-diameter gear, but in this case, as shown in Fig. 2, when the chain is wound around the large-diameter gear side 3 a, 3 b, 3 c of the rear multi-stage gear It is designed such that the chain does not automatically shift upward from the large-diameter gear 2 a of the front side or the medium-diameter gear 2 b, or does not cause an abnormal sound due to poor coupling of the chain to the gear. The off-guide tooth 2 aac is applied with a chamfer of the dimension P toward the outer side in the width direction of the bicycle, and the chamfering of the dimension q is applied to the inner side of the bicycle in the width direction of the bicycle 2abb. The auxiliary tooth 2acb is subjected to a chamfer of a size 〇 to assist the tilting of the chain by the off-lead tooth 2aac. In order to increase the shifting property of the upward shifting gear at a large load, as shown in Fig. 7, the cutting can be cut like a disengaging tooth 2aaa to increase the inner side of the bicycle in the width direction of the decoupling 2aba. If the angle is too extreme, if the chain is shaken due to large vibration or the like, or the path of the chain is tilted as shown in the figure of 200836971^2, even if the shifting operation is not performed, even if When the front derailleur is not moved, there is still a problem that the chain automatically shifts toward the small-diameter gear side or that the misalignment with the gear is generated even if the gear is not shifted. Further, in order to increase the shifting speed of the small-diameter gear 2c toward the intermediate-diameter gear 2b and the middle-diameter gear 2b toward the large-diameter gear 2a, as shown in Fig. 9, the small-diameter gear side surface of the large-diameter gear and the medium-diameter gear It is preferable to temporarily hold the protrusions 8 a, 8 b of the chain at the time of shifting, and to make it protrude as far as possible toward the small-diameter gear side, but if it is too protruding, when the chain is shaken due to vibration or the like, or the chain When the path is in the state shown in Fig. 3, there is a case where the chain comes into contact with the protruding portion to generate an abnormal sound. Moreover, since most recent bicycles use a shifting system and must be frequently shifted at a determined position, it is more difficult to perform a smooth shifting. Further, in the case of the shifting system, although the optimum shifting point is set by the wire rope adjustment, as described above, when the torque is applied to the chain, it is difficult to obtain a smooth shifting speed in the set shifting point. Wire rope adjustment has also become a troublesome thing. In addition, as in the case of Japanese Patent Laid-Open No. Hei 6-3 05 47 5, although a modification of the front derailleur is proposed to improve the shifting speed, in this case, although the shifting property of the upward shifting is slightly improved, it is still impossible. It is expected to have a substantial improvement at large loads, and there is no improvement at all upshifts. In a slightly more detailed description, the purpose of Japanese Patent Application Laid-Open No. Hei 6- 3 0 5 4 7 5 is to relax the interfering sound between the chain and the inner panel while in the state shown in FIG. 2, and to shift upwards. The shifting performance is not much different from the conventional construction. 200836971 Because the contact sound with the chain is moderated, it can be used to improve the shifting performance even though it can exceed the gear plate (〇ver shi ft). However, if this is done, the performance of the upward shifting will be extremely reduced, so the result Still can't go beyond the toothed disc, and it still can't greatly improve the shifting performance compared with the conventional structure. The present invention has been made in an effort to solve the above problems, and provides a bicycle front shifting system that can smoothly obtain a smooth shift even when a torque is applied to a chain, and can also be easily adjusted by a shift. (Means for Solving the Problem) In order to achieve the above object, in the present invention, a gear other than a minimum-diameter gear of a front sprocket composed of at least two or more gears is formed into a chain that can be easily and automatically shifted upward. And the auxiliary plate is assembled on the front derailleur so that the chain does not automatically shift downward due to vibration or tilt. [Embodiment] More specifically, for example, in the case of a front sprocket composed of three gears, part or all of the maximum diameter gear and the intermediate diameter gear are designed such that the chain is vibrated or tilted, even if the front derailleur is not moved, the chain Still automatically shifting toward the small-diameter gear side, or the meshing of the chain and the gear is deteriorated to produce an abnormal sound shape, and on the inner side of the front derailleur bicycle width direction, does not automatically face the small-diameter gear side The auxiliary plate is assembled in a manner of shifting, or in such a manner that the meshing of the chain and the gear is deteriorated to generate an abnormal sound, so that automatic shifting or abnormal sound of the chain is not generated. In addition, the auxiliary plate is designed to be detachable, so that the effect of the auxiliary plate can be reduced due to wear, etc., and can be replaced with a new product, and the auxiliary plate can be formed by a sound absorbing material or the sound absorbing effect can be alleviated. Chain contact 200836971 ' sound. [Examples] Hereinafter, examples of the invention will be described with reference to the drawings. Fig. 1 is a view showing a general driving vehicle having an exterior transmission before and after, and Fig. 2 is a state in which the chain is automatically shifted toward the small-diameter gear side or is difficult to smoothly wrap around the gear, and Fig. 3 is a gear set on the gear. FIG. 4 and FIG. 5 are explanatory views of the embodiment of the present invention, and FIG. 6 is an explanatory view of the tooth profile of the current gear, FIG. 7 and FIG. The figure shows an explanatory view of the tooth profile of the gear that is easy to automatically shift, and FIG. 9 is a shifting state diagram of the gear from the middle diameter gear to the large diameter gear, and FIG. 10 is a state diagram in which the chain is held by the auxiliary plate, and FIG. The chain is wound around the state diagram of the front large diameter gear and the rear large diameter gear, and the first two is a state diagram of the chain wound around the front middle diameter gear and the rear large diameter gear. In the present invention, in order to greatly improve the shifting property of the upward shifting, the disengagement guide teeth are formed into the shape of the teeth 2aaa as shown in Fig. 7, and 2 to 3 pieces of the disengagement guide teeth are made to be de-toothed. The shape of the tooth 2aba is such that the chain is more easily detached toward the small-diameter gear side. The detachment guide tooth 2aaa is used to cut the conventional tooth 2aac, and the purpose thereof is to make the chain easy to tilt toward the smaller diameter gear side, and to provide the inner side of the bicycle width direction of the bicycle 2abb from the tooth removal 2aba. The chamfer q has a larger chamfer t, the purpose of which is to disengage even when the chain is only slightly inclined, and the off-guide auxiliary tooth 2 aca is provided with a chamfer outside the width direction of the bicycle 2 acb. The large chamfer 1· is intended to make the inclination of the chain larger by the off-guide tooth 2 aaa. -10- 200836971 • In another embodiment, as shown in Fig. 8, the 'offering teeth 2 aab' are not cut as the off-guide teeth 2aaa, and the bicycle is turned outward in the width direction. The corner is made to have a larger chamfer s than the chamfer p of the conventional disengagement guiding tooth 2aac, thereby achieving the purpose of making the chain easy to tilt toward the smaller diameter gear side. Although the gears other than the minimum-diameter gear are provided with such a shape of the disengagement guide tooth, the disengagement tooth, and the disengagement guide auxiliary tooth, in this state, when the chain is tilted as shown in FIG. 2, even if it is not operated In the front derailleur, the chain will still automatically shift to the side of the small-diameter gear, or it will produce abnormal sound due to the poor connection of the chain to the gear. On the other hand, in the state of Fig. 2, the tooth profile of the disengagement guide tooth, the disengagement tooth, and the disengagement guide auxiliary tooth is set such that the chain is automatically shifted to the small diameter gear side or an abnormal sound is generated. On the other hand, on the inner panel 4b of the front derailleur 4, the auxiliary plate 7 is integrally or detachably provided, and the positional relationship between the auxiliary plate and the inner panel in the bicycle width direction is as shown in Fig. 2 At this time, it is set such that the inner panel 4b is not in direct contact with the chain and is first contacted by the auxiliary panel. This is because the inner plate is generally made of a metal of high rigidity, so that when the chain contacts the inner plate, a metal tone with an uncomfortable feeling is generated, so that the inner plate does not directly contact the chain. In more detail, when the chain is wound around the large diameter gear of the sprocket and the largest diameter gear of the rear free flywheel, the portion where the chain and the inner plate 4b are most easily contacted is as shown in Fig. 1, at point p. In the vicinity of 1, the surface 7a of the auxiliary plate is placed at the rear portion at a position earlier than the point p1 in contact with the chain, and because the chain is wound around the sprocket, the largest of the radial gear and the rear free flywheel In the case of the radial gear, the portion where the chain and the inner plate 4b are most easily contacted is *11-200836971'. As shown in Fig. 12, near the point P2, the surface 7b of the auxiliary plate is disposed at the rear portion thereof. Point P2 is in contact with the chain earlier. In the case of using a sprocket and a front derailleur configured as described above, the following effects will be described. As in the present embodiment, when the off-guide tooth, the off-tooth removal, and the off-guide auxiliary tooth are made into an extreme shape, although the upward shift can be greatly improved, the chain is in the state as shown in FIG. 2, even if not When the front derailleur is actuated, it will still automatically shift upwards, or even if it does not shift upwards, the chain will still be inferior to the gears and produce an abnormal sound. 'Because the chain is larger than the normal path to the small diameter gear. The side is tilted and leans toward the smaller diameter gear side. However, 'before the present invention' is in the state of Fig. 2, as shown in Fig. 10, because the auxiliary plate is placed in contact with the chain or has a small gap, even if the chain is intended to be closer than the usual path When the small-diameter gear side is still held by the auxiliary plate, the normal path can be maintained without automatically shifting up, or the chain-to-gear winding is deteriorated to generate an abnormal sound. At this time, although the contact sound is generated by the contact of the chain with the auxiliary plate, the auxiliary plate is formed of a material which can relax the contact sound with the chain, such as a resin, etc., in general, and therefore does not cause a feeling of discomfort. The contact sound can be further alleviated by further using a resin material having a silencing effect, or inserting a damping effect between the inner panel and the auxiliary panel. In the present embodiment, the auxiliary plate 7 is attached to the inner panel by the pin 9, but the auxiliary plate 7 and the inner panel 4b may be integrally formed, and the surface 7a and the surface 7b may be attached or adhered. The material of the muffling effect, or the inner panel 4 b may be formed by the material with the sound-absorbing effect of 200836971 •. According to the case of the shifting chain before the disengagement, the shape of the gear of the shape of the gear, by: show, lend, but if the protrusion is shown, in the protrusion can, but 4b and the chain result, in the second figure In the state of upshifting, because the degree of upward shifting is automatically performed when the auxiliary board is held, the shape of the picking tooth, the disengagement, and the off guiding auxiliary tooth are set, so when the actuator is oriented toward the small path When the gear side moves, it will not be held by the auxiliary plate, and the chain will be immediately hung on the small diameter gear side. In addition, even when the chain is wound around the gear 3 d of the rear free flywheel, the shape of the disengagement guide tooth, the disengagement tooth, and the disengagement guide auxiliary tooth can be easily separated, so that the upward change can be greatly improved. b. In the upward shift, in the case of the conventional configuration, for example, when shifting from the middle to the large-diameter gear, the front derailleur moves the inner plate 4b toward the large-diameter gear side to press the chain toward the large-diameter gear side, and thereafter 9图户ϋ The chain is lifted by the protrusion 8 a, and the chain is moved to the large-diameter gear. I. As described above, since the shifting is difficult when a large load is applied, although 8 a is more prominent toward the small-diameter gear side However, if the chain is tilted as shown in Fig. 3, the chain is in contact with the protrusion to produce an abnormal sound, and the height is limited. In addition, the performance can be improved by overtaking the toothed disc, because at the end of the shift After that, the inner slats of the front derailleur are in contact with each other to generate an abnormal sound, so that it is impossible to carry out the overtaking of the sprocket wheel, and the current state of the art is that sufficient shifting performance cannot be obtained. However, in the present invention, the auxiliary plate 7 is brought into contact earlier than the contact between the inner plate and the chain. Therefore, even after shifting beyond the toothed disk, an abnormal sound such as a metal sound is not generated, so that it can be sufficiently Beyond the toothed disc, the result of 200836971 can greatly improve the shifting performance from the small-diameter gear side to the large-diameter gear side even if a large load is applied. As described above, in the present invention, since the tooth shape of the large-diameter gear and the medium-diameter gear is made into a shape that is easy to automatically shift, the shifting performance of the upward shifting is greatly improved, so that even if it slightly exceeds the toothed disc, it does not fall. The shifting performance of upshifting, as a result, can greatly improve the shifting performance of upshifting and upshifting. Further, the present invention is not limited to the embodiment. In the front sprocket, in the case where the chain is inclined with respect to the gear, the automatic shifting tooth shape can be made, and in the case of the front derailleur, when the chain is inclined with respect to the gear, When the chain is in contact with the auxiliary board, it is not necessary to produce a contact sound having an uncomfortable feeling. (Effect of the Invention) In the conventional shifting system, although the front sprocket-shaped tooth profile or the front derailleur is modified to improve the shifting performance, if the shifting performance is to be extremely improved, an automatic shifting or an abnormal sound is generated. Therefore, there is still a limit to the improvement. The current situation is that sufficient shifting performance cannot be obtained at high load. In addition, by the generalization of the shifting system, it is very troublesome to adjust at any point that can satisfy either the upshift and the upshift. As a result, there has to be compromise on a certain level of performance. The present invention is to solve the problem of the current situation in one place, by making the tooth shape of the gear other than the small-diameter gear of the front sprocket into an automatically shiftable shape, and simultaneously setting an auxiliary plate in the front derailleur to keep the chain from being Automatic shifting can greatly improve the shifting performance of the upshift at high load, and by setting the auxiliary board and greatly improving the shifting performance of the upshift, the front derailleur-14-200836971 - beyond the toothed disc, so can also By greatly improving the shifting performance of the upshift, by using the combination of the sprocket and the front derailleur of the present invention, it is possible to obtain a great effect that has not been achieved so far. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a general bicycle having an exterior transmission before and after. Fig. 2 is a view showing a state in which the chain is automatically shifted toward the small-diameter gear side or is difficult to smoothly wrap around the gear. Fig. 3 is a view showing a state in which the shifting projection provided on the gear and the chain are likely to be in contact with the f sound. Fig. 4 is an explanatory view showing an embodiment of the present invention. Fig. 5 is an explanatory view showing an embodiment of the present invention. Fig. 6 is an explanatory view of the tooth profile of the current gear. Fig. 7 is an explanatory view of the tooth profile of the gear which is easy to automatically shift. Fig. 8 is an explanatory view of the tooth profile of the gear which is easy to automatically shift. Fig. 9 is a diagram showing the shifting state of the self-diameter gear toward the large-diameter gear. Figure 10 is a state diagram in which the chain is held by the auxiliary plate. % Figure 11 is a state diagram of the chain wrapped around the front large diameter gear and the rear large diameter gear. Figure 12 is a state diagram of the chain wrapped around the front and rear large diameter gears. [Main component symbol description] 2 aaa De-guide tooth 2 aab De-guide tooth 2 aac De-guide tooth -15- 200836971 2 aba De-toothing 2 ab b De-toothing 2 aca De-guided auxiliary tooth 2 acb off-off assisting tooth Q chamfering T chamfering chamfering angle R chamfering P chamfering S chamfering 2a large diameter gear 2b medium diameter gear 2 c small diameter gear 3 a , 3 b , 3 c large diameter gear 3d small diameter gear 4 刖transmission 4 a outer plate 4b inner plate 4 c recovery spring 5 rear derailleur 5 a outer plate 5b inner plate 5 c recovery spring 6 chain-16 200836971 7 auxiliary plate 7a, 7b auxiliary plate surface 8a, 8b Protrusion 9 pin