M442978 五、新型說明： 【新型所屬之技術領域】 本創作是一種鏈輪’特別是關於一種嚙合於鏈條 的自行車用之鏈輪及自行車用之鏈輪組合體。 【先前技術】 用於自行車的鏈輪，係嚙合於鏈條，對於鏈條進 行驅動及被驅動的動作。該鏈輪嚙合於此鏈條時接觸 鏈條會產生聲音。以往已知減輕嚙合鏈條時的接觸音 的鏈輪（例如特開2011-241964號公報）^以往的鏈輪 係在旋轉部件（spinning reel)的齒部向著徑方向内侧 形成環狀凹槽，在環狀凹槽將環狀的兩個緩衝環 (cushion ring)設成彼此可滑動接觸者。 在以往的鏈輪，由於環狀的凹槽形成於齒部，所 以為了維持齒部的強度，齒部厚度會變厚。因此，特 別是難以使用在需要薄型化的自行車用之鏈輪。 【新型内容】 本創作的課題是在自行車用鏈輪中，不增厚齒部 的厚度，即可減輕鏈輪與鍵條接觸的聲音。 本創作的自行車用之鏈輪，是嚙合於鏈條的自行 車用之鏈輪。自行車用之鏈輪具備：鏈輪本體與非金 屬製的緩衝部件。鏈輪本體具有：金屬製的齒部；齒 底部，被配置在齒部之間；第一側面；第二側面，位 於第一側面的相反侧；以及凹部，被設於第一側面與 第二側面中的至少任一者。緩衝部件之至少一部分被 3 M442978 配置於凹部，緩衝部件延伸到比齒底部更徑方向的外 側。 在此自行車用之鏈輪，凹部被設於鏈輪本體的側 面，配置於該凹部的緩衝部件延伸到比齒底部更徑方 向的外側。因此，當鏈條嚙合於鏈輪時，鏈條會接觸 非金屬製的緩衝部件，而不是金屬製的齒底部。藉 此，不增厚齒部的厚度，即可以減輕鏈輪與鏈條接觸 的聲音。 緩衝部件，係從設有前述凹部的側面在鏈輪旋轉 中心轴的軸方向突出，被配置在凹部的狀況下，除了 有緩衝機能外，還有間隔物的機能來規定軸方向並列 的兩個自行車用鏈輪的間隔。 根據本創作，在鏈輪本體的側面設有凹部，配置 於該凹部的緩衝部件延伸到比齒底部更徑方向的外 侧。因此，當鏈條嚙合於鏈輪時，鏈條會接觸非金屬 製的緩衝部件，而不是金屬製的齒底部。藉此，不增 厚齒部的厚度，可以減輕鏈輪與鏈條接觸的聲音。 又，藉由緩衝部件的至少一部分被配置在在鏈輪 本體所形成的凹部，可以防止緩衝部件容易從鏈輪本 體脫落。 【實施方式】 <第一實施形態> 在第一圖中，採用本創作的第一實施形態的自行 車用之後輪穀（rear hub) 10，具備：輪轂軸40，可裝 置在自行車框架；輪轂體41，被支持在輪轂軸40自由 旋轉；以及飛輪（free wheel) 42，可一體旋轉地被連 4 M442978 接在輪轂體41。 輪轂轴40疋快拆（quick reiease)式的輪穀軸，具 有：中空的軸本體44 ;以及快拆機構45，被配置在軸 本體44的内周側。在軸本體44的兩端部，有階層的鎖 定螺帽7〇a、70b被旋入至軸方向外側。 輪轂體41為例如鋁合金或鈦合金製的筒狀部件。 輪轂體41是在外周面兩端部形成有轂凸緣（hubflange) 4la_、41b的大致筒狀部件，轂凸緣41a、41b嚙止圖未 的輪輻（spoke)。輪轂體41係一端被第一軸承43a —阓成在輪轂軸40自由旋轉。在輪轂體41的他端（第 “I右側端），連接有飛輪42成可一體旋轉。輪轂體 =端經由飛輪42被第二轴承43b支持成在輪較轴 υ自由旋轉。 47a^輪42係在外周部具有花鍵(sPline)47a，該花鍵 鏈私^具有複數個（例如9個）後鏈輪(下稱自行車用之 繞赫t2a〜四的鏈輪組合體22，可連接成可成一體地 =輪旋轉中心軸c旋轉。在自行車用鏈輪22a〜22i 鏈二二配置有間隔物23，間隔物23規定相鄰自行車用 的鏈輪旋轉中心軸c的軸方向的間隔。 如，第二圖所示，自行車用之鍵輪22a的齒數，為例 齒齡^」，齒數最少。前鏈輪221的齒數為例如「32」， 多。又，中間的7個自行車用之鏈輪22b〜22h 1^數為例如「12」、「14」、「16」、「17」、「21」、 50 乂一28」 ’齒數依序增加。如第一圖所示，鏈條 7合於鏈輪22a〜22i中的任一者。如第五圖所示， «•西、5〇具有：滾筒（r〇Uer)5〇a; 一對内鏈節50b，被相 自，滾筒5〇3被裝置在該一對内鏈節5〇b之兩端成 旋轉，以及一對外鏈節5〇c，被連接於内鏈節 5 5〇b。 體旋轅〒所示，飛輪42具有：内筒部件46，可-内St在輪穀體41 ;外筒部件47，被配置在 西内己❸卜周側；以及爪式的單向離合器48，被 件47的一°部_^牛46與外筒部件47之間，只傳達外筒部 的仃進方向的旋轉到内筒部件46。 接下來說明關於本創作的第一實施形態的自行車 鏈輪22a〜22i。又，在以τ的說明，說明關於自 用之鏈輪22e«其他自行車用之鏈輪22a〜22d以 @ ^行車用之鏈輪22f〜22i，基本結構與自行車用之 p . 22e相同，由於只有如前述的齒數不同，所以省略 說明。因此，其他自行車用鏈輪22a〜22d以及自行車 用鏈輪22f〜22i也具備後述的結構。 自行車用之鍵輪22e’如第三圖所示，係喃合於鍵 條50。圖未顯示的自行車曲軸的旋轉經由鏈條5〇被傳 達至自行車用之鏈輪22e。如第三圖、第四圖以及第五 圖所示’自行車用之鏈輪22e具備鏈輪本體24與緩衝 部件26。鏈輪本體24具有：金屬製的齒部30 ;齒底部 31 ’被配置在齒部30之間；第一側面32 ;第二側面 33 ’位於第一侧面32的相反側；凹部34，被設於第一 側面32與第二側面33中的至少任一者；以及花鍵嚙合 部35。 複數個（例如17個）齒部30相隔間隔被配置於周 方向。齒部30被配置在鏈條50的一對内鏈節50b或是 一對外鏈節50c (參照第五圖）之間。在一般的自行車 用之鏈輪，鏈條50的滾筒50a可以接觸齒底部31。但 是’在本創作，鏈條50不接觸齒底部31。 第一側面32是自行車用之鍵輪22e被裝置在自行 6 M442978 車的狀態下向著外側的面。第二側面33是位於第一側 面32相反側的面，是向著内側的面。 在第一實施形態，一對凹部34係環狀内凹形成在 第一側面32以及第二側面33。凹部34的外周緣34a 被配置在比齒底部31還更徑方向的外側。凹部34的内 周緣34b被配置在比齒底部31還更徑方向的内側。因 此，凹部34被形成在徑方向挾著齒底部31。又，凹部 34的外周緣34a在形成齒底部31的部分分開。花鍵嚙 合部35嚙合於飛輪42所設的花鍵47a成可一體旋轉。 花鍵嚙合部35具有：複數個突出部35a，被配置在鏈 輪本體24的内周部，且在周方向相隔間隔。 •緩衝部件26分別被固定在一對凹部34。緩衝部件 26為例如合成橡膠等彈性體製的環狀部件。緩衝部件 26藉由接著等適當固定手段被固定於凹部34。又，也 可以將鏈輪本體24裝置在模具内，將緩衝部件26藉由 喪入成型（insert molding)等適當成型手段與鏈輪本體 24 —體形成。 緩衝部件26延伸到比齒底部31更徑方向的外側。 具體來說，緩衝部件26的外周面26a位於比連接齒底 部31最内周侧部分的齒底圓31a還更徑方向的外側。 因此，緩衝部件26的外周面26a的一部分，在齒底部 31的形成部分向外部露出。又，緩衝部件26被配置在 凹部34成與第一側面32及第二側面33為同一面。緩 衝部件26配置於凹部34内的部分，被形成為延伸到比 齒底部31更徑方向的外側。因此，在第一實施形態， 鏈條50的滾筒50a會接觸緩衝部件26。藉此，使緩衝 部件26的鏈輪旋轉中心軸C的軸方向的厚度為需要的 最小限度而可達成輕量化，並可以減輕鏈輪與鏈條接 7 M442978 觸的聲音。 在如此結構的自行車用之鏈輪22e，當曲軸旋轉， 鏈條50在行進方向被循環驅動，則自行車用之鏈輪 22e在行進方向旋轉。此時，鏈條50依序嚙合於自行 車用鏈輪22e的齒部30。在自行車用鏈輪22e，延伸到 比齒底部31更徑方向外側的緩衝部件26，被配置在鏈 輪本體24的第一侧面32以及第二側面33。因此，當 鏈條50嚙合於自行車用之鏈輪22e時，鏈條50會接觸 緩衝部件26而不是鏈輪本體24的齒底部31。具體來 說，因為一對緩衝部件26被配置在凹部34成與第一側 面32及第二側面33為同一面，所以鏈條50的滾筒50a 會接觸彈性體製的緩衝部件26。因此，不會增厚齒部 30的厚度，即可以減輕鏈輪22e與鏈條50接觸的聲 音。 <第二實施形態> 如第六圖所示，關於在第二實施形態的自行車用 之鏈輪122e，凹部134僅被設於鏈輪本體124的第一側 面132。又，凹部134比第一實施形態形成得更深，緩 衝部件126被配置在比第一側面132更内凹的凹部 134。又，緩衝部件126被配置在滾筒50a的軸方向的 大致中心位置。其他結構與第一實施形態一樣。在如 此的第二實施形態，不會增厚齒部130的厚度，即可 以減輕鏈輪122e與鏈條50接觸的聲音，並達成自行車 用之鏈輪122e的輕量化與結構的簡單化。 再者，在第二實施形態，也可以將緩衝部件不配 置在滾筒50a的軸方向的中心位置，而是配置在比中心 位置更接近第一側面132的位置。又，凹部也可以不 設於第一側面132，而僅設於第二側面133。再者，也 8 M442978 可以將緩衝部件配置在凹部i34成與 二側面133為同一面。 谢面132及弟 〈第三實施形態> 之鏈以圖所示’在關於第三實施形態的自行車用 側:部234分別被設於鏈輪本㈣的第- 被μ 1二側面233 °凹部234的外周緣234a， ::輪本體224的齒底部231更徑方向的内 成邻八>凹部234的外周緣234a，在齒底部231的形 ί 23：^； ί 〇 5 ^ ^ 邛234破形成為環狀。 以芬Ϊ衝部件226被配置在凹部234錢第一側面232 &^士―側面233在鏈輪旋轉中心軸C (參照第三圖） 的軸方向突出。緩衝部件226從第—側面加以及第二 側面233犬出的突出部226a，延伸到比齒底部23丨更徑 方向的外侧。又，突出部施的厚度（突出量）丁，是 相鄰的自行車用之鏈輪（例如自行車用之鏈輪 之，的間隔L的-半。藉此，藉由使突出部22如接觸 相的自行車用鏈輪的突出部，緩衝部件226具有間 隔物的機能來規定自行車用鏈輪222e與相鄰的自行車 ，鏈輪的間隔。在此，為了使緩衝部件226具有間隔 勿$機％’緩衝部件226是比彈性體硬質的碳纖維強 化樹脂製或合成樹脂製。 緩衝部件226延伸到徑方向外側的外周部，由於 在鏈輪旋轉中心軸c的轴方向比第—側面232以及第二 側面233更突出，所以不接觸鏈條5〇的滾筒5〇&，而是 接觸内鏈㈣b或外鏈節5Ge。其他結構與第一實施形 態一樣。 藉此，由於在喷合時鏈條50的内鏈節50b或外鏈 9 M442978 節50c接觸碳纖維強化樹脂製或合成樹脂製的緩衝部件 226，所以不增厚齒部230的厚度，即可以減輕鏈輪與 鏈條50的接觸音。又，由於緩衝部件226具有間隔物 的機能，所以不需要特別設有間隔物。 <第四實施形態> 如第八圖所示，在關於第四實施形態的自行車用 之鏈輪322e，與第一實施形態同樣形狀的凹部334分 別被設於鏈輪本體324的第一側面332以及第二側面 333。 衝部=第是 疋…弟只施形態同樣的結構，被配置 在凹部334成與第一側面332為同一面。第一緩衝部件 326f延伸到比齒底部331更徑方向的外側。 被形成在第二側面333的凹部334所配置的第 衝部件326g，被配置在凹部334成 &的 在鏈輪旋轉中心轴c(參照第三m的： ί :二 衝部件326g從第二側面333在S =犬出的犬出部326a的厚度（突出量 Ϊ用之鏈輪处與相鄰的自行車用之鍵輪（:二 326a接觸相鄰的自行車用之鏈輪的出部 鏈輪的第-緩衝部件），第二緩衝部件326giJ:;鄰 物的機能來規定自行車用鏈輪322e與有，隔 鏈輪的間隔。在此，為了使第二緩衝部鄰% 2用 隔物的機能並與第-緩衝部件326f千具有間 件326f以及緩衝部件326g是比彈性體=質部 化樹脂製或合成樹脂製。 硬質的峡纖維強 第二缓衝部件326g配置於凹部334的部分，是與 10 M442978 第一緩衝部件326f同樣的形狀，延伸到比齒底部331 更徑方向的外側。因此，在第四實施形態，第一緩衝 部件326f與第二緩衝部件326g，與第一實施形態一 樣，接觸鏈條50的滚筒50a。其他結構與第一實施形 態一樣。 藉此，由於在嚙合時鏈條50的滾筒50a接觸碳纖 維強化樹脂製或合成樹脂製的緩衝部件326，所以不增 厚齒部330的厚度，即可以減輕鏈輪與鏈條50接觸的 聲音。又，由於第二緩衝部件326g具有間隔物的機 能，所以不需要特別設有間隔物。 又，第四實施形態中，在最小徑的自行車用之鏈 輪22a的第二緩衝部件，不需要設有突出部。 又，如第八圖以兩點鏈線所示，在被形成在第一 側面332的凹部334所配置的第一緩衝部件326f，也可 以設有突出部。又，突出部的徑方向位置可以是與凹 部重疊的任何位置。再者，將突出部設於第一側面側 的第一緩衝部件326f的狀況，不需要將突出部設於最 大徑側的自行車用之鏈輪22i。 在前述四個實施形態，在鏈輪本體的第一側面或 第二側面所設的凹部内，設置緩衝部件的至少一部 分。因此，可以防止在使用自行車用鏈輪中，緩衝部 件容易從鏈輪本體脫落。 <其他實施形態> 雖然以上說明了關於本創作的一實施形態，但本 創作並不受限於上述實施形態，在不脫離本創作要旨 的範圍内可以進行各種變更。特別是本說明書所寫到 的複數個實施形態以及變形例，可以依需要進行任意 組合。 11 M442978 (a) 雖然在前述的四個實施形態，凹部以及緩衝 部件被形成為環狀，但本創作不受限於此。在第九圖 中，複數個（例如17個）凹部434以及複數個（例如 17個）緩衝部件426，相隔間隔被設於鏈輪本體424的 周方向。凹部434被設於鏈輪本體424的第一側面432 以及第二側面（圖未顯示）。緩衝部件426與第一實施 形態一樣，被配置在凹部434成與第一側面432及第二 側面為同一面。又，緩衝部件426延伸到比齒底部431 更徑方向的外側。即使在如此的實施形態，也達成與 第一實施形態同樣的作用效果。 又，也可以將複數個緩衝部件構成為與從第二實 施形態到第四實施形態一樣。 (b) 在前述實施形態，雖然以後鏈輪為例來說明 本創作的自行車用之鏈輪，但本創作不受限於此。本 創作可以也適用於具有複數個前鏈輪的鏈輪組合體。 (c) 在前述實施形態，雖然以具有複數個後鏈輪 的可變速鏈輪組合體為例來說明本創作，但本創作不 受限於此。本創作也可以適用於例如1個後鏈輪以及1 個前鍵輪。 (d) 在前述第九圖所示的實施形態，雖然將大致 矩形的凹部相隔間隔配置在周方向，但也可以將圓形 的凹部相隔間隔配置在周方向。 (e) 也可以將緩衝部件形成為C字形成其兩端被 固定在外側面的凹部與内側面的凹部，且跨越齒底 部。 【圖式簡單說明】 12 M442978 第一圖：採用本創作一實施形態鏈輪組合體的後輪轂 的半截剖面圖。 第二圖：本創作一實施形態的鏈輪組合體的正面圖。 第三圖：本創作一實施形態的自行車用之鏈輪的正面 圖。 第四圖··第三圖所示的自行車用之鏈輪的齒部的正面 放大圖。 第五圖：第三圖被切斷面v-v切斷的剖面圖。 第六圖：第二實施形態的自行車用之鏈輪相當於第五 圖的圖。 第七圖··第三實施形態的自行車用之鏈輪相當於第五 圖的圖。 第八圖：第四實施形態的自行車用之鏈輪相當於第五 圖的圖。 第九圖：其他實施形態的自行車用之鏈輪相當於第三 圖的圖。 【主要元件符號說明】 10後輪轂 22鏈輪組合體 22a〜22i、122e、222d、222e、322d、322e 自行車用之 鏈輪 23間隔物 24、124、224、324、424 鏈輪本體 26、126、226、426 緩衝部件 26a外周面 30、130、230、430 齒部 13 M442978 31、 13卜231、33卜431齒底部 31a齒底圓 32、 132、232、332、432 第一側面 33、 133、233、333 第二側面 34、 134、234、334、434 凹部 34a、234a外周緣 34b内周緣 35花鍵嚙合部 40輪轂軸 41輪轂體 42飛輪 43a第一軸承 43b第二軸承 44轴本體 45快拆機構 46内筒部件 47外筒部件 47a花鍵 48單向離合器 50鏈條 50a滾筒 50b内鏈節 50c外鏈節 70a、70b鎖定螺帽 226a突出部 326f第一緩衝部件 326g第二緩衝部件 C鏈輪旋轉中心軸 M442978 L間隔 T厚度M442978 V. New description: [New technical field] This creation is a sprocket', especially for a bicycle sprocket and a bicycle sprocket assembly that mesh with the chain. [Prior Art] A sprocket for a bicycle is engaged with a chain to drive and be driven by the chain. When the sprocket engages the chain, it contacts the chain to produce sound. A sprocket for reducing the contact sound when the chain is engaged is known (for example, JP-A-2011-241964). The conventional sprocket is formed with an annular groove on the inner side in the radial direction of the tooth portion of the rotating reel. The annular groove sets the two annular cushion rings to be slidable to each other. In the conventional sprocket, since the annular groove is formed in the tooth portion, the thickness of the tooth portion is increased in order to maintain the strength of the tooth portion. Therefore, it is particularly difficult to use a sprocket for a bicycle that requires thinning. [New content] The subject of this creation is to reduce the thickness of the tooth portion in the bicycle sprocket and reduce the sound of the sprocket and the key bar. The bicycle sprocket of the present invention is a sprocket for a bicycle that is engaged with a chain. The sprocket for bicycles has a sprocket body and a non-metallic cushioning member. The sprocket body has: a metal tooth portion; a tooth bottom portion disposed between the tooth portions; a first side surface; a second side surface on an opposite side of the first side surface; and a concave portion disposed on the first side surface and the second side At least any of the sides. At least a portion of the cushioning member is disposed in the recess by the 3 M442978, and the cushioning member extends to the outer side in the radial direction of the bottom of the tooth. In the bicycle sprocket, the concave portion is provided on the side surface of the sprocket body, and the cushioning member disposed in the concave portion extends to the outer side in the radial direction of the tooth bottom portion. Therefore, when the chain is engaged with the sprocket, the chain contacts the non-metallic cushioning member instead of the metal tooth bottom. Therefore, the thickness of the tooth portion is not thickened, that is, the sound of the sprocket in contact with the chain can be reduced. The cushioning member protrudes from the side surface on which the concave portion is provided in the axial direction of the central axis of the sprocket rotation, and is disposed in the concave portion. In addition to the cushioning function, there are two functions of the spacer to define the axial direction. The spacing of the bicycle sprocket. According to the present invention, a concave portion is provided on the side surface of the sprocket body, and the cushioning member disposed in the concave portion extends to the outer side in the radial direction of the tooth bottom portion. Therefore, when the chain is engaged with the sprocket, the chain contacts the non-metallic cushioning member instead of the metal bottom of the tooth. Thereby, the thickness of the tooth portion is not increased, and the sound of the sprocket in contact with the chain can be reduced. Further, since at least a part of the cushioning member is disposed in the concave portion formed in the sprocket body, it is possible to prevent the cushioning member from being easily detached from the sprocket body. [Embodiment] <First Embodiment> In the first drawing, a rear rear wheel 10 for a bicycle according to a first embodiment of the present invention includes a hub axle 40 that can be mounted on a bicycle frame; The hub body 41 is supported to freely rotate on the hub axle 40; and a free wheel 42, which is integrally rotatably connected to the hub body 41 by 4 M442978. The wheel axle 40 疋 quick reiease type volute shaft has a hollow shaft body 44 and a quick release mechanism 45 disposed on the inner peripheral side of the shaft body 44. At both ends of the shaft body 44, the level of the lock nuts 7a, 70b are screwed to the outside in the axial direction. The hub body 41 is, for example, a tubular member made of an aluminum alloy or a titanium alloy. The hub body 41 is a substantially cylindrical member in which hub flanges 4a and 41b are formed at both end portions of the outer peripheral surface, and the hub flanges 41a and 41b engage spokes of the figure. One end of the hub body 41 is freely rotated by the first bearing 43a on the hub axle 40. At the other end of the hub body 41 (the right end of the "I"), the flywheel 42 is coupled for integral rotation. The hub body = end is supported by the second bearing 43b via the flywheel 42 to freely rotate on the wheel axle. 47a^ Wheel 42 The sPline 47a is provided on the outer peripheral portion, and the spline chain has a plurality of (for example, nine) rear sprocket wheels (hereinafter referred to as a sprocket assembly 22 for bicycles t2a to four, which can be connected The wheel rotation center axis c can be integrally rotated. The bicycle sprocket wheels 22a to 22i are provided with a spacer 23, and the spacer 23 defines the axial direction of the adjacent sprocket rotation center axis c of the bicycle. For example, as shown in the second figure, the number of teeth of the key wheel 22a for a bicycle is, for example, the tooth age, and the number of teeth is the least. The number of teeth of the front sprocket 221 is, for example, "32", and more, the seven bicycles in the middle are used. The number of teeth of the sprocket 22b to 22h is, for example, "12", "14", "16", "17", "21", 50 乂28". The number of teeth increases sequentially. As shown in the first figure, the chain 7 Cooperating with any of the sprockets 22a to 22i. As shown in the fifth figure, «•西,5〇 has: roller (r〇Uer) 5〇a; a pair of inner links 50b, being self-aligned, the drum 5〇3 is rotated by the device at both ends of the pair of inner links 5〇b, and a pair of outer links 5〇c is connected to the inner link 5 5〇b. As shown in FIG. 2, the flywheel 42 has an inner cylinder member 46, an inner cylinder St in the wheel body 41, an outer cylinder member 47 disposed on the inner side of the inner cylinder, and a claw type one-way clutch 48. Between the one-section portion of the member 47 and the outer tubular member 47, only the rotation of the outer tubular portion in the direction of the advancement is transmitted to the inner tubular member 46. Next, the bicycle sprocket according to the first embodiment of the present invention will be described. 22a to 22i. In addition, in the description of τ, the sprocket 22e to 22d for the bicycle sprocket 22a to 22d for the bicycle sprocket 22f to 22i for the bicycle, the basic structure and the bicycle p. Since the number of teeth is the same as that of 22e, the description will be omitted. Therefore, the other bicycle sprocket wheels 22a to 22d and the bicycle sprocket wheels 22f to 22i are also provided as described later. The bicycle key wheel 22e' is as shown in the third figure. As shown, it is spliced to the key strip 50. The rotation of the bicycle crankshaft not shown is conveyed via the chain 5〇 To the bicycle sprocket 22e. As shown in the third, fourth and fifth figures, the bicycle sprocket 22e is provided with a sprocket body 24 and a cushioning member 26. The sprocket body 24 has a metal tooth portion. 30; the tooth bottom 31' is disposed between the teeth 30; the first side 32; the second side 33' is located on the opposite side of the first side 32; the recess 34 is disposed in the first side 32 and the second side 33 And at least one of the spline engaging portions 35. The plurality of (for example, 17) tooth portions 30 are arranged in the circumferential direction at intervals. The tooth portion 30 is disposed between the pair of inner links 50b of the chain 50 or an outer link 50c (refer to the fifth figure). In a conventional bicycle sprocket, the drum 50a of the chain 50 can contact the tooth bottom 31. However, in the present creation, the chain 50 does not contact the bottom 31 of the tooth. The first side surface 32 is a surface on which the bicycle key wheel 22e is placed on the outer side in the state of the self-propelled 6 M442978 vehicle. The second side surface 33 is a surface on the opposite side of the first side surface 32 and is a surface facing inward. In the first embodiment, the pair of recessed portions 34 are annularly concavely formed on the first side face 32 and the second side face 33. The outer peripheral edge 34a of the recessed portion 34 is disposed on the outer side in the radial direction of the tooth bottom portion 31. The inner peripheral edge 34b of the recessed portion 34 is disposed on the inner side in the radial direction of the tooth bottom portion 31. Therefore, the concave portion 34 is formed in the radial direction of the tooth bottom portion 31. Further, the outer peripheral edge 34a of the recessed portion 34 is separated at a portion where the tooth bottom portion 31 is formed. The spline engagement portion 35 is engaged with the spline 47a provided in the flywheel 42 so as to be rotatable integrally. The spline engagement portion 35 has a plurality of projections 35a disposed on the inner peripheral portion of the sprocket body 24 and spaced apart in the circumferential direction. The cushioning members 26 are fixed to the pair of recesses 34, respectively. The cushion member 26 is an elastic member such as an elastomer. The cushioning member 26 is fixed to the concave portion 34 by a suitable fixing means. Further, the sprocket body 24 may be housed in a mold, and the cushion member 26 may be integrally formed with the sprocket body 24 by a suitable molding means such as insert molding. The cushioning member 26 extends to the outer side in the radial direction of the tooth bottom portion 31. Specifically, the outer peripheral surface 26a of the cushioning member 26 is located on the outer side in the radial direction of the tooth bottom circle 31a of the innermost peripheral side portion of the connecting tooth bottom portion 31. Therefore, a part of the outer peripheral surface 26a of the cushioning member 26 is exposed to the outside at the portion where the tooth bottom portion 31 is formed. Further, the cushioning member 26 is disposed in the concave portion 34 so as to be flush with the first side surface 32 and the second side surface 33. The portion of the cushion member 26 disposed in the recess 34 is formed to extend to the outer side in the radial direction of the tooth bottom portion 31. Therefore, in the first embodiment, the drum 50a of the chain 50 contacts the cushioning member 26. Thereby, the thickness of the sprocket rotation center axis C of the damper member 26 in the axial direction is minimized, and the weight can be reduced, and the sound of the sprocket and the chain link 7 M442978 can be reduced. In the bicycle sprocket 22e thus constructed, when the crankshaft rotates and the chain 50 is circulated in the traveling direction, the bicycle sprocket 22e rotates in the traveling direction. At this time, the chain 50 is sequentially engaged with the tooth portion 30 of the bicycle sprocket 22e. In the bicycle sprocket 22e, the cushion member 26 that extends to the outer side of the tooth bottom portion 31 in the radial direction is disposed on the first side face 32 and the second side face 33 of the sprocket body 24. Therefore, when the chain 50 is engaged with the sprocket 22e for bicycle, the chain 50 contacts the cushioning member 26 instead of the tooth bottom 31 of the sprocket body 24. Specifically, since the pair of cushioning members 26 are disposed in the recessed portion 34 so as to be flush with the first side surface 32 and the second side surface 33, the roller 50a of the chain 50 contacts the elastic cushioning member 26. Therefore, the thickness of the tooth portion 30 is not thickened, that is, the sound of the sprocket 22e in contact with the chain 50 can be alleviated. <Second Embodiment> As shown in the sixth embodiment, in the bicycle sprocket 122e according to the second embodiment, the recessed portion 134 is provided only on the first side surface 132 of the sprocket body 124. Further, the concave portion 134 is formed deeper than the first embodiment, and the cushion member 126 is disposed in the concave portion 134 which is recessed than the first side surface 132. Further, the cushioning member 126 is disposed at a substantially central position of the drum 50a in the axial direction. The other structure is the same as that of the first embodiment. In the second embodiment as described above, the thickness of the tooth portion 130 is not increased, and the sound of the sprocket 122e in contact with the chain 50 can be reduced, and the weight and structure of the bicycle sprocket 122e can be reduced. Further, in the second embodiment, the cushion member may be disposed not at the center position of the drum 50a in the axial direction but at a position closer to the first side surface 132 than the center position. Further, the concave portion may not be provided on the first side surface 132 but only on the second side surface 133. Further, in 8 M442978, the cushion member may be disposed in the concave portion i34 so as to be flush with the two side faces 133. In the bicycle side: the portion 234 of the third embodiment is provided on the first side of the sprocket (four), the second side 233 ° of the sprocket wheel (the fourth embodiment). The outer peripheral edge 234a of the recess 234, the outer bottom edge 234a of the tooth bottom 231 of the wheel body 224 is more in the radial direction than the outer periphery 234a of the recess 234, and the shape of the bottom 231 of the tooth 231 is 形23:^; ί 〇 5 ^ ^ 邛234 is broken into a ring shape. The defrosting member 226 is disposed so that the first side surface 232 of the concave portion 234 and the side surface 233 protrude in the axial direction of the sprocket rotation center axis C (see FIG. 3). The cushioning member 226 extends from the first side surface and the protruding portion 226a of the second side surface 233 to the outer side of the tooth bottom portion 23A in the radial direction. Further, the thickness (protrusion amount) applied to the protruding portion is an sprocket for an adjacent bicycle (for example, a half of the interval L of the sprocket for bicycles. Thereby, by making the protruding portion 22 such as a contact phase The protruding portion of the bicycle sprocket, the cushioning member 226 has a function of a spacer to define the interval between the bicycle sprocket 222e and the adjacent bicycle and sprocket. Here, in order to make the cushioning member 226 have a gap of not less than % The cushioning member 226 is made of a carbon fiber reinforced resin or a synthetic resin which is harder than the elastic body. The cushioning member 226 extends to the outer peripheral portion on the outer side in the radial direction, and the axial direction of the sprocket rotation center axis c is larger than the first side surface 232 and the second side surface. 233 is more prominent, so it does not touch the roller 5〇& of the chain 5〇, but contacts the inner chain (4)b or the outer link 5Ge. The other structure is the same as that of the first embodiment. Thereby, since the chain 50 is inside the spray. The link 50b or the outer link 9 M442978 section 50c is in contact with the carbon fiber reinforced resin or the synthetic resin cushion member 226, so that the thickness of the tooth portion 230 is not thickened, that is, the contact sound of the sprocket and the chain 50 can be reduced. Since the punching member 226 has a function of a spacer, it is not necessary to provide a spacer. [Fourth embodiment] As shown in the eighth embodiment, the bicycle sprocket 322e according to the fourth embodiment is first and The concave portions 334 having the same shape in the embodiment are respectively provided on the first side surface 332 and the second side surface 333 of the sprocket body 324. The punching portion is the same as the first embodiment, and is disposed in the concave portion 334 and the first portion. The side surface 332 is the same surface. The first cushioning member 326f extends to the outer side in the radial direction of the tooth bottom portion 331. The first punching member 326g disposed in the concave portion 334 formed on the second side surface 333 is disposed in the concave portion 334 In the sprocket rotation center axis c (refer to the third m: ί: the second punching member 326g from the second side surface 333 at S = the thickness of the canine out portion 326a of the dog (the protruding amount of the sprocket and the adjacent sprocket a bicycle key wheel (the second 326a contacts the first cushioning member of the outer sprocket of the adjacent bicycle sprocket), the second cushioning member 326giJ:; the function of the adjacent body defines the bicycle sprocket 322e and , the spacing of the sprocket. Here, in order to make the second The function of the spacer 2% spacer 2 is different from that of the first cushion member 326f and the cushion member 326g is made of an elastomer = a resin or a synthetic resin. The member 326g is disposed in the recess 334 and has the same shape as the 10 M442978 first cushioning member 326f, and extends to the outer side in the radial direction of the tooth bottom portion 331. Therefore, in the fourth embodiment, the first cushioning member 326f and the second embodiment The cushioning member 326g is in contact with the drum 50a of the chain 50 as in the first embodiment. The other structure is the same as the first embodiment. Thereby, since the roller 50a of the chain 50 is in contact with the carbon fiber reinforced resin or the synthetic resin cushion member 326 at the time of meshing, the thickness of the tooth portion 330 is not increased, that is, the sound of the sprocket in contact with the chain 50 can be reduced. Further, since the second cushioning member 326g has the function of a spacer, it is not necessary to provide a spacer. Further, in the fourth embodiment, it is not necessary to provide the protruding portion in the second cushioning member of the bicycle sprocket 22a having the smallest diameter. Further, as shown in the eighth figure, as shown by the two-dot chain line, the first cushioning member 326f disposed in the concave portion 334 formed in the first side surface 332 may be provided with a protruding portion. Further, the radial direction position of the protruding portion may be any position overlapping the concave portion. Further, in the case where the protruding portion is provided on the first cushioning member 326f on the first side surface side, it is not necessary to provide the protruding portion to the bicycle sprocket 22i on the largest diameter side. In the above four embodiments, at least a portion of the cushioning member is provided in the recess provided in the first side or the second side of the sprocket body. Therefore, it is possible to prevent the cushioning member from being easily detached from the sprocket body in the use of the bicycle sprocket. <Other Embodiments> Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. In particular, the plurality of embodiments and modifications described in the present specification can be arbitrarily combined as needed. 11 M442978 (a) Although in the above four embodiments, the concave portion and the cushioning member are formed in a ring shape, the present creation is not limited thereto. In the ninth diagram, a plurality of (e.g., 17) concave portions 434 and a plurality of (e.g., 17) cushioning members 426 are provided at intervals in the circumferential direction of the sprocket body 424. The recess 434 is provided on the first side 432 and the second side of the sprocket body 424 (not shown). Similarly to the first embodiment, the cushioning member 426 is disposed in the concave portion 434 so as to be flush with the first side surface 432 and the second side surface. Further, the cushioning member 426 extends to the outer side in the radial direction of the tooth bottom portion 431. Even in such an embodiment, the same operational effects as those of the first embodiment are achieved. Further, a plurality of buffer members may be configured in the same manner as in the second embodiment to the fourth embodiment. (b) In the above embodiment, the bicycle sprocket of the present invention will be described as an example of a sprocket in the future, but the present invention is not limited thereto. This creation can also be applied to a sprocket assembly having a plurality of front sprockets. (c) In the above embodiment, the present invention has been described by taking a variable speed sprocket assembly having a plurality of rear sprocket as an example, but the present creation is not limited thereto. This creation can also be applied to, for example, one rear sprocket and one front key wheel. (d) In the embodiment shown in the ninth embodiment, the substantially rectangular recesses are arranged at intervals in the circumferential direction. However, the circular recesses may be arranged at intervals in the circumferential direction. (e) It is also possible to form the cushion member so that the C-shape forms a concave portion whose both ends are fixed to the concave portion on the outer side surface and the concave portion on the inner side surface, and spans the bottom portion of the tooth. [Simple description of the drawing] 12 M442978 First figure: A half cross-sectional view of the rear hub of the embodiment of the sprocket assembly. Second: A front view of a sprocket assembly of an embodiment of the present invention. Fig. 3 is a front view of a bicycle sprocket according to an embodiment of the present invention. Fig. 4 is an enlarged front view of the tooth portion of the bicycle sprocket shown in the third figure. Fig. 5 is a cross-sectional view of the third figure cut by the cut surface v-v. Fig. 6 is a view showing a bicycle sprocket according to a second embodiment. Fig. 7 is a view showing a bicycle sprocket according to a third embodiment. Eighth view: The bicycle sprocket according to the fourth embodiment corresponds to the fifth diagram. Fig. 9 is a view showing a bicycle sprocket according to another embodiment. [Main component symbol description] 10 rear hub 22 sprocket assembly 22a to 22i, 122e, 222d, 222e, 322d, 322e bicycle sprocket 23 spacer 24, 124, 224, 324, 424 sprocket body 26, 126 226, 426 cushioning member 26a outer peripheral surface 30, 130, 230, 430 tooth portion 13 M442978 31, 13 231, 33 431 tooth bottom 31a tooth bottom circle 32, 132, 232, 332, 432 first side 33, 133 233, 333 second side 34, 134, 234, 334, 434 recess 34a, 234a outer circumference 34b inner circumference 35 spline engagement portion 40 hub shaft 41 hub body 42 flywheel 43a first bearing 43b second bearing 44 shaft body 45 Quick release mechanism 46 inner cylinder member 47 outer cylinder member 47a spline 48 one-way clutch 50 chain 50a drum 50b inner link 50c outer link 70a, 70b locking nut 226a projection 326f first cushioning member 326g second cushioning member C Sprocket rotation central axis M442978 L interval T thickness