JP3681136B2

JP3681136B2 - Transmission rotor

Info

Publication number: JP3681136B2
Application number: JP27869996A
Authority: JP
Inventors: 洋一竹内
Original assignee: Enplas Corp
Current assignee: Enplas Corp
Priority date: 1996-09-30
Filing date: 1996-09-30
Publication date: 2005-08-10
Anticipated expiration: 2016-09-30
Also published as: JPH10103450A

Description

【０００１】
【発明の属する技術分野】
本発明は例えばプーリー、或いは、歯車、スプロケット、回転カム等の複合体に好適に適用することができる伝動回転体の構造に関し、更に詳しくは、複数の分割片を接合してなる合成樹脂製の伝動回転体に関する。
【０００２】
【従来の技術】
例えば回転伝動部品の１つであるＶベルト用プーリーは、その外周部に断面略台形状のベルト係合溝を有する。さらに内周に歯形を形成したタイミングベルトと係接されるプーリーのベルト係合溝の底部にはタイミングベルトの歯形と噛合する歯形が全周に亘って形成される。このようなプーリーはベルト係合溝の両側壁を形成する一対のフランジ部を有し、その内側面はテーパー状に形成される。
【０００３】
【発明が解決しようとする課題】
上記のようなプーリーを合成樹脂で一体成形する場合、プーリーはその外周部に軸方向断面が略凹状の凹部を有するので、該プーリーを一体成形するための金型にはプーリーのベルト係合溝を形成するための駒を環状に配置する必要がある。このため、成形後に成形品であるプーリーを金型から取り出す際にはプーリーの両フランジ間に位置する駒を移動させる必要がある。このため、一般のＶベルト用プーリーを成形するときは、駒を少なくとも直径方向に２分割する必要がある。また、上述したタイミングベルト用のプーリーを成形するときは駒をさらに多数に分割して放射状に移動させる必要がある。したがって成形用の金型構造が複雑になり、合成樹脂製プーリーの製造コストが増大する原因となる。
【０００４】
また、プーリー部、歯車部、スプロケット部、カム部等を適宜に組み合わせて複合化した伝動回転体においても、外周部の断面形状が略凹状となる場合には上述したプーリーと同様の問題が生じ得る。
【０００５】
そこで、例えばプーリーにおいては、その一方のフランジ部をベルト係合溝の底部から切り離すようにプーリーを軸方向に２分割し各々別体に成形するようにすれば、成形後に金型内から成形されたプーリーを取り出す際に、ベルト係合溝を形成するための駒を移動させる必要がなくなるので、金型構造を簡素化することができる。しかし、プーリーを上記の如く２分割構造とした場合、２つの分割片の結合時に両者を互いに同心に位置合わせする必要があるとともに、両者を軸方向に移動防止および抜け防止可能に強固に結合する必要がある。
【０００６】
実公昭６２−２０９３１号公報には上フランジとハブを備えた下フランジとを別個に成形して結合する２分割構造の合成樹脂製のテープリールが開示されている。このテープリールにおいては、ハブの頂面に形成した段部と複数の突起を上フランジの下面に形成した段部および複数の孔にそれぞれ嵌合させて両フランジを結合させるように構成されており、突起の先端には孔からの抜けを防止するためのフックが形成されている。
【０００７】
しかしながら、上記のテープリールにおいては円筒状に形成された浅い段部の直径寸法誤差により両フランジに半径方向の遊びが生じたり、両段部の嵌合が困難となったりするので、遊びのない同心結合を確実に得ることが困難である。また、先端にフックを有する突起の高さ寸法誤差により突起のフックと上フランジとの間に軸方向の遊びが生じたり、フックの係止が困難となったりするので、軸方向に遊びのない結合を確実に得ることが困難である。
【０００８】
したがって、本発明の目的は製造が容易で、且つ、半径方向および軸方向に遊びの生じない強固な結合構造の伝動回転体を提供することにある。
【０００９】
【課題を解決するための手段】
上記目的を達成するために、本発明は、合成樹脂製の回転体本体の外周部の少なくとも一部に軸方向断面が略凹状の凹部を有する伝動回転体において、前記回転体本体が前記凹部の底面部と内側面との境界部で分断された複数の分割片で構成され、互いに隣接する２つの分割片のうちの一方の分割片の一端面側にはその回転軸心上に曲率中心をもつ断面円形の嵌合穴が、また他方の分割片には該嵌合穴と嵌合する嵌合片がそれぞれ設けられ、前記一方の分割片の他端面側にはその回転軸心上に曲率中心をもつ断面円形の凹陥部が形成されて該凹陥部と前記嵌合片との間にディスク状の連結壁部が形成され、該連結壁部に前記嵌合穴及び前記凹陥部間を貫通する挿通孔が形成され、前記他方の分割片には該挿通孔に挿通されて前記凹陥部の底面上の該挿通孔の端縁に軸方向抜け防止可能に係止されるフック片が設けられ、前記嵌合穴と前記嵌合片の嵌合面がそれぞれテーパー面とされ、前記嵌合片が前記嵌合穴に圧入された状態で前記フック片が前記凹陥部の底面上で前記挿通孔の端縁に係止されることを特徴とする。
【００１０】
上記構成の伝動回転体においては、合成樹脂製の分割片に形成される断面円形の嵌合穴と嵌合片の嵌合面をそれぞれテーパー面としているので、互いに隣接する２つの分割片を結合するときに、嵌合穴と嵌合片を確実に密着状態で嵌合させることができる。しかも、嵌合片が嵌合穴に圧入された状態でフック片が挿通孔の端縁に係止されるので、嵌合穴への嵌合片の圧入によって両分割片を強く結合し且つ両分割片の離脱を確実に防止することができる。また、分割片の結合時に嵌合穴と嵌合片との締め代を調整することより両分割片の軸方向の相対位置を調整することができるので、フック片を確実に且つ軸方向に遊びのない状態で挿通孔の端縁に係止させることができる。したがって、半径方向に遊びの生じない同心結合を確実に得ることができる。また、嵌合穴と嵌合片との嵌合時にフック片を挿通孔端縁に係止させることができるので、互いに結合された２つの分割片の離脱を確実に防止することができる。しかも、上記構成によれば、挿通孔の端縁に係止されるフック片の先端部を分割片の端面に形成される凹陥部内に置くことができるので、該フック片の先端部が分割片の端部から外部に突出することを防止できる。
【００１１】
好ましくは、前記嵌合穴と前記嵌合片との嵌合部が前記挿通孔および前記フック片よりも分割片の外周部側に形成される。係る構成によれば、分割片の回転軸心上に曲率中心をもつ嵌合穴と前記嵌合片との嵌合部の曲率半径を大きくとることができるので、嵌合穴および嵌合片自体の心合わせ精度を容易に高めることができると共に、両分割片の外周部に形成される伝動部を高精度に心合わせすることができる。また、嵌合部の曲率半径を大きくできるので嵌合面の面積を容易に増大させることができ、心合わせ結合の安定性を高めることができる。
【００１２】
また、本発明は、合成樹脂製の回転体本体の外周部の少なくとも一部に軸方向断面が略凹状の凹部を有する伝動回転体において、前記回転体本体が前記凹部の底面部と内側面との境界部で分断された３つの分割片で構成され、該３つの分割片のうちの中間の分割片の一端面側及び他端面側にそれぞれその回転軸心上に曲率中心をもつ断面円形の嵌合穴が形成されて両嵌合穴間にディスク状の連結壁部が形成され、他の２つの分割片のうちの一方には前記中間の分割片の前記一端面側の嵌合穴と嵌合する嵌合片が、また他方には前記中間の分割片の前記他端面側の嵌合穴と嵌合する嵌合片がそれぞれ設けられ、前記中間の分割片の前記連結壁部に両嵌合穴間を貫通する複数の挿通孔が形成され、前記他の２つの分割片には該挿通孔に挿通されて前記挿通孔の端縁に軸方向抜け防止可能に係止されるフック片がそれぞれ設けられ、前記嵌合穴と前記嵌合片の嵌合面がそれぞれテーパー面とされ、前記嵌合片が前記嵌合穴に圧入された状態で前記フック片が前記挿通孔の端縁に係止されることを特徴とする。
上記構成の伝動回転体においては、合成樹脂製の分割片に形成される断面円形の嵌合穴と嵌合片の嵌合面をそれぞれテーパー面としているので、中間の分割片に対して他の２つの分割片を結合するときに、嵌合穴と嵌合片を確実に密着状態で嵌合させることができる。しかも、嵌合片が嵌合穴に圧入された状態でフック片が挿通孔の端縁に係止されるので、嵌合穴への嵌合片の圧入によって中間の分割片に対し他の２つの分割片を強く結合し且つ他の２つの分割片の離脱を確実に防止することができる。また、分割片の結合時に嵌合穴と嵌合片との締め代を調整することより中間の分割片に対し他の２つの分割片の軸方向の相対位置を各々調整することができるので、フック片を確実に且つ軸方向に遊びのない状態で挿通孔の端縁に係止させることができる。したがって、半径方向に遊びの生じない同心結合を確実に得ることができる。また、嵌合穴と嵌合片との嵌合時にフック片を挿通孔端縁に係止させることができるので、中間の分割片に対する他の２つの分割片の離脱を確実に防止することができる。しかも、上記構成によれば、挿通孔の端縁に係止されるフック片の先端部を断面円形の嵌合穴内に置くことができるので、該フック片の先端部が分割片の外部に突出することを防止できる。
【００１３】
【発明の実施の形態】
以下、図面を参照して本発明の実施例につき説明する。
【００１４】
【実施例】
図１および図２は本発明をプーリーに適用した場合の第１実施例を示すものである。これらの図を参照すると、プーリーは合成樹脂製の回転体本体２からなり、その中心部にハブ３を、また外周部に断面台形状のタイミングベルト（図示省略）と係合する凹部すなわちベルト係合溝４を形成したものとなっている。ベルト係合溝４は軸方向断面略台形の凹状をなし、該ベルト係合溝４の両側面を形成するフランジ部５，６の内側面はそれぞれテーパー状に形成されている。ベルト係合溝４の底部４Ａにはタイミングベルトの内周面に形成される歯形と噛合する歯形４Ｂが全周に亘り形成されている。この種の伝動回転体（プーリー）においては、伝動回転体本体２の外周部にはベルト係合溝４の底部４Ａの歯形４Ｂの箇所を底面部とする軸方向略凹状の凹部が全周に亘り形成されることとなるので、伝動回転体本体２を合成樹脂で一体成形しようとすると、金型にはベルト係合溝４の歯形４Ｂを形成するための多数の駒を放射状に移動可能に配置する必要がある。
【００１５】
プーリーの回転体本体２は２つの分割片２Ａ，２Ｂにより構成されており、一方の分割片２Ａはハブ３と、フランジ部５と、ベルト係合溝４の底部４Ａを形成するリム部７と、前記ハブ３とリム部７とを連結するディスク状の連結壁部８とを一体に有している。また他方の分割片２Ｂはディスク状をなして他方のフランジ部６を備えており、両分割片２Ａ，２Ｂは、伝動部であるベルト係合溝４をその底部４Ａと上記他方のフランジ部６との境界部で分断されている。他方の分割片２Ｂの中央部には適度のクリアランスを介してハブ３と嵌合する中心孔９が形成されている。
【００１６】
さらに、一方の分割片２Ａのリム部７の内側には該分割片２Ａの回転軸心上に曲率中心をもつ断面円形の嵌合穴１０が形成され、また他方の分割片２Ｂには該嵌合穴１０と嵌合する嵌合片１１が設けられている。また、一方の分割片２Ａの連結壁部８には複数（図示実施例では３つ）の挿通孔１２が周方向に等角度間隔あけて形成されており、他方の分割片２Ｂには各々の挿通孔１２に挿通されて該挿通孔１２の端縁に軸方向抜け防止可能に係止される複数のフック片１３が設けられている。そして、嵌合穴１０と嵌合片１１の嵌合面はそれぞれ截頭円錐形状のテーパー面とされている。挿通孔１２にはフック片１３の挿入を容易にするための面取り部１２Ａが形成されている。また、フランジ６にはフック片１３を成形する際の駒の移動を可能にする貫通孔６Ａが形成されている。
【００１７】
前述したように、外周部に略台形状のベルト係合溝４を有するプーリーにおいては、両フランジ５，６の内側面はベルト係合溝４が略台形状をなすようにテーパー面となっているので、両分割片２Ａ，２Ｂの中心がずれて結合されると、ベルト係合溝４にベルトを掛けたときにベルトの側面がフランジ部５，６の内側面とぴったり嵌合しなくなり、ベルトの回転に歪が生じ、きしみ音や偏磨耗が生じる原因となる。しかし、上記実施例においては、上記の如く、嵌合穴１０と嵌合片１１との嵌合面をテーパー面としているので、両分割片２Ａ,２Ｂを結合するときに、両分割片２Ａ、２Ｂを容易に心合わせすることができる。また、嵌合穴１０と嵌合片１１を確実に密着状態で嵌合させることができるので、半径方向に遊びの生じない同心結合を確実に得ることができる。さらに、嵌合穴１０と嵌合片１１との嵌合時にフック片１３を挿通孔１２の端縁に係止させることができるので、互いに結合された２つの分割片２Ａ，２Ｂの離脱を確実に防止することができる。
【００１８】
なお、図示実施例では挿通孔１２の端縁に係止させるためのフック片１３の先端の爪部１３Ａは分割片２Ａ，２Ｂの半径方向外方に突出しているが、半径方向内方或いは半径方向と直角な方向に突出していてもよい。
【００１９】
さらに、上記実施例においては、嵌合片１１が嵌合穴１０に圧入された状態でフック片１３が挿通孔１２の端縁に係止されるように寸法設定されている。したがって、嵌合穴１０への嵌合片１１の圧入によって両分割片２Ａ，２Ｂを強く結合することができる。また、分割片２Ａ，２Ｂの結合時に嵌合穴１０と嵌合片１１との締め代を調整することより両分割片２Ａ，２Ｂの軸方向の相対位置を調整することができるので、フック片１３を確実に且つ軸方向に遊びのない状態で挿通孔１２の端縁に係止させることができる。
【００２０】
さらに、上記実施例においては、嵌合穴１０と嵌合片１１との嵌合部が挿通孔１２およびフック片１３よりも分割片２Ａ，２Ｂの外周部側に形成されているので、分割片２Ａ，２Ｂの回転軸心上に曲率中心をもつ嵌合穴１０と嵌合片１１との嵌合部の曲率半径を大きくとることができる。したがって、嵌合穴１０と嵌合片１１との心合わせ精度を容易に高めることができる。しかも、嵌合穴１０と嵌合片１１との嵌合部を両分割片２Ａ，２Ｂの外周部に近接させて心合わせすることができるので、プーリーの外周部に形成されるベルト係合溝４の箇所における両分割片２Ａ，２Ｂの心合わせ精度を高めることができる。
【００２１】
さらに、上記実施例においては、フック片１３の係止される挿通孔１２の端縁がフック片１３を有する分割片２Ｂとは反対側の分割片２Ａの端面に形成された断面円形（図１参照）の凹陥部１４の底面部に形成されているので、挿通孔１２の端縁に係止されるフック片１２の先端部を分割片２Ａの端面に形成される凹陥部１４内に配置させることができ、該フック片１３の先端部が分割片２Ａの端面から突出することを防止できる。
【００２２】
なお、両分割片２Ａ，２Ｂの廻り止めは嵌合穴１０への嵌合片１１の圧入による摩擦結合と、挿通孔１２の壁面と該挿通孔１２に挿通されたフック片１３の側面との当接により達成してもよいが、図示実施例のように、一方の分割片２Ａのハブ３の外周面にＤカット部３Ａを形成し、他方の分割片２Ｂの中心孔９をこのＤカット部３Ａに適合させるようにすれば、より確実な廻り止めを達成することができる。
【００２３】
また更に、嵌合穴１０と嵌合片１１の嵌合面の傾斜角度は、両分割片２Ａ，２Ｂを結合する際の作業性と、分割片２Ａ，２Ｂの心合わせ精度を考慮して設定すべきである。
【００２４】
図３から図５までは本発明の第２実施例を示したものである。この第２実施例の伝動回転体における伝動回転体本体２０は、ハブ２１と、外周部に歯形２３を備えた小歯車部２２と、該小歯車部２２よりも歯先円直径の大きな歯形２５を備えた大歯車部２４と、外周部にカム面２７を備えたカム部２６とを一体化したものであり、小歯車部２２の両側に大歯車部２４とカム部２６がそれぞれ配置されている。したがって、この種の伝動回転体においては、伝動回転体本体２０の外周部には小歯車部２２の歯形２３の箇所を底面部とする軸方向略凹状の凹部が全周に亘り形成されることとなるので、伝動回転体本体２０を合成樹脂で一体成形しようとすると、金型には小歯車部２２の歯形２３を形成するための多数の駒を放射状に移動可能に配置する必要がある。
【００２５】
そこで、本発明の第２実施例においては、伝動回転体本体２０が２つの分割片２０Ａ，２０Ｂからなり、一方の分割片２０Ａはハブ２１と小歯車部２２と大歯車部２４とを一体に有し、他方の分割片２０Ｂはカム部２６を有している。一方の分割片２０Ａにおける小歯車部２２及び大歯車部２４は略リング状をなしており、ディスク状の連結壁部２８を介してハブ２１と連結されている。この伝動回転体本体２０の外周部は軸方向断面が略凹状の凹部を有し、小歯車部２２の歯形２３が該凹部の底面部をなすので、両分割片２０Ａ，２０Ｂは該凹部の底面部すなわち小歯車２２の歯形２３とカム部２６との境界部で分断されている。カム部２６を有する他方の分割片２０Ｂの中央部には適度のクリアランスを介してハブ３と嵌合する中心孔２９が形成されている。
【００２６】
さらに、一方の分割片２０Ａの小歯車部２２の内側には該分割片２０Ａの回転軸心上に曲率中心をもつ断面円形の嵌合穴３０が形成され、また他方の分割片２０Ｂには該嵌合穴３０と嵌合する嵌合片３１が設けられている。また、一方の分割片２０Ａの連結壁部２８には複数（図示実施例では３つ）の挿通孔３２が周方向に等角度間隔あけて形成されており、他方の分割片２０Ｂには各々の挿通孔３２に挿通されて該挿通孔３２の端縁に軸方向抜け防止可能に係止される複数のフック片３３が設けられている。そして、嵌合穴３０と嵌合片３１の嵌合面はそれぞれ截頭円錐形状のテーパー面とされている。
【００２７】
上記第２実施例においては、嵌合穴３０と嵌合片３１との嵌合面がテーパー面とされているので、両分割片２０Ａ,２０Ｂを結合するときに、両分割片２０Ａ、２０Ｂを容易に心合わせすることができる。また、嵌合穴３０と嵌合片３１を確実に密着状態で嵌合させることができるので、半径方向に遊びの生じない同心結合を確実に得ることができる。さらに、嵌合穴３０と嵌合片３１との嵌合時にフック片３３を挿通孔３２の端縁に係止させることができるので、互いに結合された２つの分割片２０Ａ，２０Ｂの離脱を確実に防止することができる。
【００２８】
なお、第２実施例においても、挿通孔３２の端縁に係止されるフック片３３の先端の爪部３３Ａは分割片２０Ａ，２０Ｂの半径方向外方に突出しているが、半径方向内方或いは半径方向と直角な方向に突出していてもよい。
【００２９】
さらに、上記第２実施例においても、嵌合片３１が嵌合穴３０に圧入された状態でフック片３３が挿通孔３２の端縁に係止されるように寸法設定されている。したがって、嵌合穴３０への嵌合片３１の圧入によって両分割片２０Ａ，２０Ｂを強く結合することができる。また、分割片２０Ａ，２０Ｂの結合時に嵌合穴３０と嵌合片３１との締め代を調整することより両分割片２０Ａ，２０Ｂの軸方向の相対位置を調整することができるので、フック片３３を確実に且つ軸方向に遊びのない状態で挿通孔３２の端縁に係止させることができる。
【００３０】
さらに、上記第２実施例においても、嵌合穴３０と嵌合片３１との嵌合部が挿通孔３２およびフック片３３よりも分割片２０Ａ，２０Ｂの外周部側に形成されているので、分割片２０Ａ，２０Ｂの回転軸心上に曲率中心をもつ嵌合穴３０と嵌合片３１との嵌合部の曲率半径を大きくとることができる。したがって、嵌合穴３０と嵌合片３１との心合わせ精度を容易に高めることができる。しかも、嵌合穴３０と嵌合片３１との嵌合部を両分割片２０Ａ，２０Ｂの外周部に近接させて心合わせすることができるので、両分割片２０Ａ，２０Ｂの外周部における心合わせ精度を高めることができる。
【００３１】
さらに、上記第２実施例においても、フック片３３の係止される挿通孔３２の端縁がフック片３３を有する分割片２０Ｂとは反対側の分割片２０Ａの端面に形成された断面円形（図３参照）の凹陥部３４の底面部に形成されているので、挿通孔３２の端縁に係止されるフック片３３の先端部を分割片２０Ａの端面に形成される凹陥部３４内に配置させることができ、該フック片３３の先端部が分割片２０Ａの端面から突出することを防止できる。
【００３２】
なお、第２実施例においては、両分割片２０Ａ，２０Ｂの廻り止めは嵌合穴３０への嵌合片３１の圧入による摩擦結合と、挿通孔３２の壁面と該挿通孔３２に挿通されたフック片３３の側面との当接により達成されるが、第１実施例と同様に、一方の分割片２０Ａのハブ２１の外周面にＤカット部を形成し、他方の分割片２０Ｂの中心孔２９をこのＤカット部に適合させるようにすれば、より確実な廻り止めを達成することができる。
【００３３】
図６及び図７は本発明の第３実施例を示したものである。この第３実施例の伝動回転体における伝動回転体本体４０は、ハブ４１と、外周部にカム面４３、４５，４７をそれぞれ備えた３つのカム部４２，４４，４６を一体化したものである。したがってこの種の伝動回転体においては、各カム部４２，４４，４６の外周部のカム面４３，４５，４７の凹凸形状により、図７に示すように、この伝動回転体本体４０の外周部には軸方向断面が略凹状の凹部が部分的に形成されている。このため、伝動回転体本体４０を合成樹脂で一体成形しようとすると、金型には中間のカム部４２の外周カム面４３を形成するための複数個の駒を移動可能に配置する必要がある。
【００３４】
そこで、本発明の第３実施例においては、伝動回転体本体４０が２つの分割片４０Ａ，４０Ｂからなり、一方の分割片４０Ａはハブ４１と中間のカム部４２とその一側に位置するカム部４４とを一体に有し、他方の分割片４０Ｂは他側のカム部４６を有している。一方の分割片４０Ａにおける２つのカム部４２，４４は略リング状をなしており、ディスク状の連結壁部４８を介してハブ４１と連結されている。両分割片４０Ａ，４０Ｂは中間のカム部４２と他側（図７中下側）のカム部４６との境界部で分断されている。カム部４６を有する他方の分割片４０Ｂの中央部には適度のクリアランスを介してハブ４１と嵌合する中心孔４９が形成されている。
【００３５】
さらに、一方の分割片４０Ａにおける中間のカム部４２の内側には該分割片４０Ａの回転軸心上に曲率中心をもつ断面円形の嵌合穴５０が形成され、また他方の分割片４０Ｂには該嵌合穴５０と嵌合する嵌合片５１が設けられている。また、一方の分割片４０Ａの連結壁部４８には複数（図示実施例では３つ）の挿通孔５２が周方向に等角度間隔あけて形成されており、他方の分割片４０Ｂには各々の挿通孔５２に挿通されて該挿通孔５２の端縁に軸方向抜け防止可能に係止される複数のフック片５３が設けられている。そして、嵌合穴５０と嵌合片５１の嵌合面はそれぞれ截頭円錐形状のテーパー面とされている。
【００３６】
上記第３実施例においては、嵌合穴５０と嵌合片５１との嵌合面がテーパー面とされているので、両分割片４０Ａ，４０Ｂを結合するときに、両分割片４０Ａ，４０Ｂを容易に心合わせすることができる。また、嵌合穴５０と嵌合片５１を確実に密着状態で嵌合させることができるので、半径方向に遊びの生じない同心結合を確実に得ることができる。さらに、嵌合穴５０と嵌合片５１との嵌合時にフック片５３を挿通孔５２の端縁に係止させることができるので、互いに結合された２つの分割片４０Ａ，４０Ｂの離脱を確実に防止することができる。
【００３７】
なお、第３実施例においても、挿通孔５２の端縁に係止されるフック片５３の先端の爪部５３Ａは分割片４０Ａ，４０Ｂの半径方向外方に突出しているが、半径方向内方或いは半径方向と直角な方向に突出していてもよい。
【００３８】
さらに、上記第３実施例においても、嵌合片５１が嵌合穴５０に圧入された状態でフック片５３が挿通孔５２の端縁に係止されるように寸法設定されている。したがって、嵌合穴５０への嵌合片５１の圧入によって両分割片４０Ａ，４０Ｂを強く結合することができる。また、分割片４０Ａ，４０Ｂの結合時に嵌合穴５０と嵌合片５１との締め代を調整することより両分割片４０Ａ，４０Ｂの軸方向の相対位置を調整することができるので、フック片５３を確実に且つ軸方向に遊びのない状態で挿通孔５２の端縁に係止させることができる。
【００３９】
さらに、上記第３実施例においても、嵌合穴５０と嵌合片５１との嵌合部が挿通孔５２およびフック片５３よりも分割片４０Ａ，４０Ｂの外周部側に形成されているので、分割片４０Ａ，４０Ｂの回転軸心上に曲率中心をもつ嵌合穴５０と嵌合片５１との嵌合部の曲率半径を大きくとることができる。したがって、嵌合穴５０と嵌合片５１との心合わせ精度を容易に高めることができる。しかも、嵌合穴５０と嵌合片５１との嵌合部を両分割片４０Ａ，４０Ｂの外周部に近接させて心合わせすることができるので、両分割片４０Ａ，４０Ｂの外周部における心合わせ精度を高めることができる。
【００４０】
さらに、上記第３実施例においても、フック片５３の係止される挿通孔５２の端縁がフック片５３を有する分割片４０Ｂとは反対側の分割片４０Ａの端面に形成された断面円形（図６参照）の凹陥部５４の底面部に形成されているので、挿通孔５２の端縁に係止されるフック片５３の先端部を分割片４０Ａの端面に形成される凹陥部５４内に配置させることができ、該フック片５３の先端部が分割片４０Ａの端面から突出することを防止できる。
【００４１】
なお、第３実施例においても、第２実施例と同様に、両分割片４０Ａ，４０Ｂの廻り止めは嵌合穴５０への嵌合片５１の圧入による摩擦結合と、挿通孔５２の壁面と該挿通孔５２に挿通されるフック片５３の側面との当接により達成されるが、第１実施例と同様に、一方の分割片４０Ａのハブ４１の外周面にＤカット部を形成し、他方の分割片４０Ｂの中心孔４９をこのＤカット部に適合させるようにすれば、より確実な廻り止めを達成することができる。
【００４２】
図８は本発明の第４実施例を示したものである。この第４実施例の伝動回転体における伝動回転体本体４０は、ハブ４１と、外周部にカム面４３、４５，４７，５５，５７をそれぞれ備えた５つのカム部４２，４４，４６，５４，５６を一体化したものである。したがってこの種の伝動回転体においては、各カム部４２，４４，４６，５４，５６の外周部のカム面４３，４５，４７，５５、５７の凹凸形状により、カム部４４とカム部４６との間において伝動回転体本体４０の外周部に軸方向断面が略凹状の凹部が部分的に形成されているとともに、カム部４４とカム部５６との間において伝動回転体本体４０の外周部に軸方向断面が略凹状の凹部が部分的に形成されている。このため、伝動回転体本体４０を合成樹脂で一体成形しようとすると、金型にはカム部４２の外周カム面４３を形成するための複数個の駒及びカム部５４の外周カム面５５を形成するための複数個の駒をそれぞれ移動可能に配置する必要がある。
【００４３】
そこで、本発明の第４実施例においては、伝動回転体本体４０が３つの分割片４０Ａ，４０Ｂ，４０Ｃからなり、隣接する２つの分割片４０Ａ，４０Ｂの関係は上記第３実施例と同様の構成とされており、また、隣接する２つの分割片４０Ａ，４０Ｃの関係は分割片４０Ａ，４０Ｂの関係と同様の構成とされている。
【００４４】
すなわち、中間の分割片４０Ａはハブ４１とカム部４２，４４，５４を一体に有し、一側の分割片４０Ｂはカム部４６を有し、他側の分割片４０Ｃはカム部５６を有している。中間の分割片４０Ａにおける２つのカム部４２，４４，５４は略リング状をなしており、ディスク状の連結壁部４８を介してハブ４１と連結されている。２つの分割片４０Ａ，４０Ｂの関係は上記第３実施例と同様であり、同一の構成要素には同一の参照符号が付してある。したがって、ここでは２つの分割片４０Ａ，４０Ｂの関係についての詳細な説明を省略する。
【００４５】
隣接する２つの分割片４０Ａ，４０Ｃの関係において、両分割片４０Ａ，４０Ｃは、分割片４０Ａのカム部５４と分割片４０Ｃのカム部５６との境界部で分断されている。カム部５６を有する分割片４０Ｃの中央部には適度のクリアランスを介してハブ４１と嵌合する中心孔５９が形成されている。
【００４６】
さらに、分割片４０Ａにおけるカム部４４，５４の内側には該分割片４０Ａの回転軸心上に曲率中心をもつ断面円形の嵌合穴６０が形成され、また他方の分割片４０Ｃには該嵌合穴６０と嵌合する嵌合片６１が設けられている。また、一方の分割片４０Ａの連結壁部４８には複数の挿通孔６２が周方向に等角度間隔あけて形成されており、他方の分割片４０Ｃには各々の挿通孔６２に挿通されて該挿通孔６２の端縁に軸方向抜け防止可能に係止される複数のフック片６３が設けられている。そして、嵌合穴６０と嵌合片６１の嵌合面はそれぞれ截頭円錐形状のテーパー面とされている。
【００４７】
さらに、嵌合穴６０と嵌合片６１との嵌合面がテーパー面とされているので、隣接する２つの分割片４０Ａ，４０Ｃを結合するときに、両分割片４０Ａ，４０Ｃを容易に心合わせすることができる。また、嵌合穴６０と嵌合片６１を確実に密着状態で嵌合させることができるので、半径方向に遊びの生じない同心結合を確実に得ることができる。さらに、嵌合穴６０と嵌合片６１との嵌合時にフック片６３を挿通孔６２の端縁に係止させることができるので、互いに結合された２つの分割片４０Ａ，４０Ｃの離脱を確実に防止することができる。
【００４８】
さらに、両分割片４０Ａ，４９Ｃの関係においても、嵌合片６１が嵌合穴６０に圧入された状態でフック片６３が挿通孔６２の端縁に係止されるように寸法設定されているので、嵌合穴６０への嵌合片６１の圧入によって両分割片４０Ａ，４０Ｃを強く結合することができる。また、分割片４０Ａ，４０Ｃの結合時に嵌合穴６０と嵌合片６１との締め代を調整することより両分割片４０Ａ，４０Ｃの軸方向の相対位置を調整することができるので、フック片６３を確実に且つ軸方向に遊びのない状態で挿通孔６２の端縁に係止させることができる。
【００４９】
図９は図１及び図２に示す上記第１実施例の変形例を示したものである。同図において上記第１実施例の構成要素と同様の構成要素には同一の参照符号が付してある。この変形例においては分割片２Ｂにその回転軸心上に曲率中心をもつ断面円形のテーパー状の嵌合穴９’が形成され、また分割片２Ａのハブ３には該嵌合穴９’と嵌合する嵌合部１０’が設けられている。したがって、この変形例においても嵌合穴９’と嵌合部１０’との嵌合により両分割片２Ａ，２Ｂを確実に同心結合させることができる。また、嵌合穴９’と嵌合部１０’との嵌合時にフック片１２を挿通孔１１の端縁に係止させることができるので、互いに結合された２つの分割片２Ａ，２Ｂの離脱を確実に防止することができる。
【００５０】
以上、図示実施例につき説明したが、本発明は上記実施例の態様のみに限定されるものではなく、特許請求の範囲に記載した発明の範囲内でその構成要素に種々の変更を加えることができる。
【００５１】
例えば、嵌合穴及び嵌合片は挿通孔及びフック片よりも分割片の回転軸心寄りに配置形成してもよい。したがって、例えば挿通孔及びフック片とハブとの間に嵌合穴及び嵌合片をそれぞれ配置してもよい。
【００５２】
また、フック片の個数は複数個が好ましいが１つであってもよい。
【００５３】
さらに、分割片はその中央部にハブの代わりに中実構造の軸部を備えていてもよい。
【００５４】
また、本発明は上記各実施例に示す歯車、カム等の組合せの他、複数のプーリー、或いは、歯車、スプロケット、プーリー、カム等を任意に組み合わせて一体化される伝動用の回転体に適用可能である。
【００５５】
また、一般に伝動回転体の場合、その回転により発生する摩擦熱などにより高温になる場合が多いので、各分割片は同一の合成樹脂材料或いは線膨張係数の近似した合成樹脂材料で構成することが望ましい。
【００５６】
【発明の効果】
以上の説明から明らかなように、本発明は、合成樹脂製の回転体本体の外周部の少なくとも一部に軸方向断面が略凹状の凹部を有する伝動回転体において、前記回転体本体が前記凹部の底面部と内側面との境界部で分断された複数の分割片で構成され、互いに隣接する２つの分割片のうちの一方の分割片の一端面側にはその回転軸心上に曲率中心をもつ断面円形の嵌合穴が、また他方の分割片には該嵌合穴と嵌合する嵌合片がそれぞれ設けられ、前記一方の分割片の他端面側にはその回転軸心上に曲率中心をもつ断面円形の凹陥部が形成されて該凹陥部と前記嵌合片との間にディスク状の連結壁部が形成され、該連結壁部に前記嵌合穴及び前記凹陥部間を貫通する挿通孔が形成され、前記他方の分割片には該挿通孔に挿通されて前記凹陥部の底面上の該挿通孔の端縁に軸方向抜け防止可能に係止されるフック片が設けられ、前記嵌合穴と前記嵌合片の嵌合面がそれぞれテーパー面とされ、前記嵌合片が前記嵌合穴に圧入された状態で前記フック片が前記凹陥部の底面上で前記挿通孔の端縁に係止されるように構成しているので、製造が容易で、且つ、半径方向および軸方向に遊びの生じない強固な結合構造の伝動回転体を提供することができる。
また、本発明は、合成樹脂製の回転体本体の外周部の少なくとも一部に軸方向断面が略凹状の凹部を有する伝動回転体において、前記回転体本体が前記凹部の底面部と内側面との境界部で分断された３つの分割片で構成され、該３つの分割片のうちの中間の分割片の一端面側及び他端面側にそれぞれその回転軸心上に曲率中心をもつ断面円形の嵌合穴が形成されて両嵌合穴間にディスク状の連結壁部が形成され、他の２つの分割片のうちの一方には前記中間の分割片の前記一端面側の嵌合穴と嵌合する嵌合片が、また他方には前記中間の分割片の前記他端面側の嵌合穴と嵌合する嵌合片がそれぞれ設けられ、前記中間の分割片の前記連結壁部に両嵌合穴間を貫通する複数の挿通孔が形成され、前記他の２つの分割片には該挿通孔に挿通されて前記挿通孔の端縁に軸方向抜け防止可能に係止されるフック片がそれぞれ設けられ、前記嵌合穴と前記嵌合片の嵌合面がそれぞれテーパー面とされ、前記嵌合片が前記嵌合穴に圧入された状態で前記フック片が前記挿通孔の端縁に係止されるように構成しているので、製造が容易で、且つ、半径方向および軸方向に遊びの生じない強固な結合構造の３分割片タイプの伝動回転体を提供することができる。
【図面の簡単な説明】
【図１】本発明の第１実施例を示すプーリーの平面図。
【図２】図１に示すプーリーの図１中Ａ−Ａ線に沿った断面図。
【図３】本発明の第２実施例を示す２つの歯車とカムを一体化した伝動回転体の平面図。
【図４】図３に示す伝動回転体の図３中Ｂ−Ｂ線に沿った断面図。
【図５】図３に示す伝動回転体の底面図。
【図６】本発明の第３実施例を示す３つのカムを一体化した伝動回転体の平面図。
【図７】図６に示す伝動回転体の図６中Ｃ−Ｃ線に沿った断面図。
【図８】本発明の第４実施例を示す５つのカムを一体化した伝動回転体の図７と類似の断面図。
【図９】図１及び図２に示す第１実施例の変形例を示すプーリーの図２と類似の断面図。
【符号の説明】
２プーリー（伝動回転体）
２Ａ，２Ｂ分割片
３ハブ
４ベルト係合溝
５，６フランジ部
７リム部
８連結壁部
１０嵌合穴
１１嵌合片
１２挿通孔
１３フック片[0001]
BACKGROUND OF THE INVENTION
 The present invention relates to a structure of a transmission rotating body that can be suitably applied to, for example, a pulley or a complex such as a gear, a sprocket, and a rotating cam, and more specifically, a synthetic resin made by joining a plurality of divided pieces. It relates to a transmission rotor.
[0002]
[Prior art]
 For example, a pulley for a V belt, which is one of rotational transmission parts, has a belt engagement groove having a substantially trapezoidal cross section on the outer peripheral portion thereof. Further, a tooth profile that meshes with the tooth profile of the timing belt is formed over the entire circumference at the bottom of the belt engagement groove of the pulley that is engaged with the timing belt having a tooth profile formed on the inner periphery. Such a pulley has a pair of flange portions forming both side walls of the belt engaging groove, and the inner surface thereof is formed in a tapered shape.
[0003]
[Problems to be solved by the invention]
 When the pulley as described above is integrally formed with a synthetic resin, the pulley has a concave portion having a substantially concave axial cross section on the outer peripheral portion thereof, so that the mold for integrally forming the pulley has a belt engagement groove of the pulley. It is necessary to arrange the pieces for forming the ring in a ring shape. For this reason, when taking out the pulley which is a molded product after shaping | molding, it is necessary to move the piece located between the both flanges of a pulley. For this reason, when molding a general V-belt pulley, it is necessary to divide the piece into two at least in the diameter direction. Further, when forming the pulley for the timing belt described above, it is necessary to divide the pieces into a large number and move them radially. Therefore, the mold structure for molding becomes complicated, which increases the manufacturing cost of the synthetic resin pulley.
[0004]
 Even in the case of a transmission rotating body obtained by combining pulley parts, gear parts, sprocket parts, cam parts, etc. as appropriate, the same problem as the above-described pulley occurs when the outer peripheral section has a substantially concave shape. obtain.
[0005]
 Therefore, for example, in the case of a pulley, if one pulley is separated from the bottom of the belt engaging groove and the pulley is divided into two parts in the axial direction and each is molded separately, it is molded from the mold after molding. When removing the pulley, it is not necessary to move the piece for forming the belt engagement groove, so that the mold structure can be simplified. However, when the pulley has a two-divided structure as described above, it is necessary to align the two concentric with each other when the two divided pieces are coupled, and the two are firmly coupled so that they can be prevented from moving and coming off in the axial direction. There is a need.
[0006]
 Japanese Utility Model Publication No. 62-20931 discloses a synthetic resin tape reel having a two-part structure in which an upper flange and a lower flange having a hub are separately molded and joined. In this tape reel, a step portion formed on the top surface of the hub and a plurality of protrusions are respectively fitted to a step portion formed on the lower surface of the upper flange and a plurality of holes, and both flanges are coupled. A hook is formed at the tip of the protrusion to prevent the protrusion from coming out.
[0007]
 However, in the above tape reel, there is no play because the radial dimension of both flanges may be caused due to the diameter dimensional error of the shallow step formed in the cylindrical shape, and it is difficult to fit the both steps. It is difficult to reliably obtain concentric bonds. In addition, there is no play in the axial direction because there is play in the axial direction between the hook of the protrusion and the upper flange due to a height error of the protrusion having a hook at the tip, or it becomes difficult to lock the hook. It is difficult to ensure a bond.
[0008]
 SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a transmission rotor having a strong coupling structure that is easy to manufacture and does not generate play in the radial and axial directions.
[0009]
[Means for Solving the Problems]
 In order to achieve the above-mentioned object, the present invention provides a transmission rotor having a recess having a substantially concave cross section in the axial direction in at least a part of an outer peripheral portion of a rotor body made of synthetic resin. One of two divided pieces that are composed of a plurality of divided pieces separated by a boundary portion between the bottom surface portion and the inner side surface and are adjacent to each otherOne side of the split pieceHas a center of curvature on its axis of rotationCircular in cross sectionThe mating hole is on the other sideSplit piecesEach is provided with a fitting piece to be fitted with the fitting hole,On the other end surface side of the one divided piece, a concave section having a circular section with a center of curvature is formed on the rotation axis, and a disk-shaped connecting wall is formed between the concave section and the fitting piece. An insertion hole penetrating between the fitting hole and the recessed portion is formed in the connecting wall portion, and the other divided piece is inserted into the insertion hole to form the insertion hole on the bottom surface of the recessed portion. A hook piece that is locked to the end edge so as to be prevented from coming off in the axial direction is provided,The fitting surface of the fitting hole and the fitting piece is a tapered surface, and the hook piece is in a state where the fitting piece is press-fitted into the fitting hole.On the bottom of the recessIt is locked to the edge of the insertion hole.
[0010]
 In the transmission rotating body having the above-described configuration, it is formed on a segment piece made of synthetic resin.Circular in cross sectionSince the fitting surfaces of the fitting hole and the fitting piece are respectively tapered surfaces, the fitting hole and the fitting piece can be securely fitted in close contact when two adjacent pieces are joined together. it can. In addition, since the hook piece is locked to the end edge of the insertion hole in a state where the fitting piece is press-fitted into the fitting hole, both the divided pieces are strongly coupled by press-fitting the fitting piece into the fitting hole, and both The separation of the divided pieces can be reliably prevented. Moreover, since the relative position in the axial direction of the two split pieces can be adjusted by adjusting the tightening margin between the fitting hole and the fitting piece when the split pieces are joined, the hook pieces can be surely played in the axial direction. It can be locked to the end edge of the insertion hole in the absence of any. Therefore, a concentric connection that does not cause play in the radial direction can be reliably obtained. In addition, since the hook piece can be locked to the edge of the insertion hole when the fitting hole and the fitting piece are fitted, the separation of the two divided pieces coupled to each other can be reliably prevented.In addition, according to the above configuration, the tip of the hook piece that is locked to the edge of the insertion hole can be placed in the recessed portion formed on the end surface of the split piece. It can prevent protruding from the edge of the outside.
[0011]
 Preferably, a fitting portion between the fitting hole and the fitting piece is formed closer to the outer peripheral portion side of the split piece than the insertion hole and the hook piece. According to this configuration, since the radius of curvature of the fitting portion between the fitting hole having the center of curvature on the rotation axis of the divided piece and the fitting piece can be increased, the fitting hole and the fitting piece itself The centering accuracy can be easily increased, and the transmission portions formed on the outer peripheral portions of the two split pieces can be centered with high accuracy. Moreover, since the curvature radius of a fitting part can be enlarged, the area of a fitting surface can be increased easily and stability of centering coupling can be improved.
[0012]
 Further, the present invention provides a transmission rotating body having a concave portion having a substantially concave axial cross section in at least a part of an outer peripheral portion of a synthetic resin rotating body main body, wherein the rotating body main body includes Each of which has a circular cross section with a center of curvature on the axis of rotation on each of the one end face side and the other end face side of the intermediate split piece of the three split pieces. A fitting hole is formed to form a disk-shaped connecting wall between the fitting holes, and one of the other two divided pieces has a fitting hole on the one end face side of the intermediate divided piece. A fitting piece to be fitted is provided on the other side, and a fitting piece to be fitted to the fitting hole on the other end surface side of the intermediate divided piece is provided on the other side. A plurality of insertion holes penetrating between the fitting holes are formed, and the other two divided pieces are inserted into the insertion holes. Hook pieces that are locked so as to be prevented from coming off in the axial direction are provided at the end edges of the insertion holes, the fitting surfaces of the fitting holes and the fitting pieces are respectively tapered surfaces, and the fitting pieces are The hook piece is locked to an end edge of the insertion hole in a state of being press-fitted into the fitting hole..
 In the transmission rotating body having the above-described configuration, the fitting hole of the circular cross section formed in the synthetic resin divided piece and the fitting surface of the fitting piece are each a tapered surface. When two divided pieces are joined, the fitting hole and the fitting piece can be reliably fitted in a close contact state. In addition, since the hook piece is locked to the end edge of the insertion hole in a state where the fitting piece is press-fitted into the fitting hole, the other two pieces are inserted into the intermediate divided piece by press-fitting the fitting piece into the fitting hole. It is possible to firmly connect the two pieces and prevent the other two pieces from coming off. Moreover, since the relative position in the axial direction of the other two divided pieces can be adjusted with respect to the intermediate divided piece by adjusting the interference between the fitting hole and the fitting piece when the divided pieces are joined, The hook piece can be securely locked to the end edge of the insertion hole without any play in the axial direction. Therefore, a concentric connection that does not cause play in the radial direction can be reliably obtained. In addition, since the hook piece can be locked to the edge of the insertion hole when the fitting hole and the fitting piece are fitted, it is possible to reliably prevent the other two divided pieces from being separated from the intermediate divided piece. it can. In addition, according to the above configuration, the tip of the hook piece that is locked to the edge of the insertion hole can be placed in the fitting hole having a circular cross section, so that the tip of the hook piece protrudes outside the split piece. Can be prevented.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
【Example】
 1 and 2 show a first embodiment when the present invention is applied to a pulley. Referring to these drawings, the pulley is composed of a rotating body body 2 made of synthetic resin. The pulley 3 is engaged with a hub 3 at the center and a timing belt (not shown) having a trapezoidal cross section at the outer periphery. The groove 4 is formed. The belt engaging groove 4 has a concave shape with a substantially trapezoidal cross section in the axial direction, and the inner side surfaces of the flange portions 5 and 6 forming both side surfaces of the belt engaging groove 4 are each tapered. A tooth profile 4B that meshes with a tooth profile formed on the inner peripheral surface of the timing belt is formed on the bottom 4A of the belt engagement groove 4 over the entire circumference. In this type of transmission rotator (pulley), an axially substantially concave recess having a bottom surface portion corresponding to the tooth profile 4B of the bottom 4A of the belt engagement groove 4 is provided on the entire outer periphery of the transmission rotator body 2. When the transmission rotor body 2 is to be integrally formed of synthetic resin, a large number of pieces for forming the tooth profile 4B of the belt engagement groove 4 can be moved radially in the mold. Need to be placed.
[0015]
 The rotating body 2 of the pulley is composed of two divided pieces 2A and 2B. One divided piece 2A includes a hub 3, a flange portion 5, and a rim portion 7 that forms a bottom portion 4A of the belt engaging groove 4. The hub 3 and the rim portion 7 are integrally provided with a disk-shaped connecting wall portion 8. The other divided piece 2B has a disk-like shape and is provided with the other flange portion 6. Both the divided pieces 2A and 2B have a belt engaging groove 4 as a transmission portion formed on the bottom portion 4A and the other flange portion 6 described above. It is divided at the boundary. A central hole 9 is formed in the central portion of the other divided piece 2B so as to be fitted to the hub 3 with an appropriate clearance.
[0016]
 Further, a fitting hole 10 having a circular cross section with a center of curvature is formed on the rotation axis of the divided piece 2A on the inner side of the rim portion 7 of one divided piece 2A, and the fitting is made on the other divided piece 2B. A fitting piece 11 for fitting with the joint hole 10 is provided. In addition, a plurality (three in the illustrated embodiment) of insertion holes 12 are formed in the connecting wall portion 8 of one divided piece 2A at equal angular intervals in the circumferential direction. A plurality of hook pieces 13 are provided which are inserted into the insertion holes 12 and locked to the end edges of the insertion holes 12 so as to be prevented from coming off in the axial direction. The fitting surfaces of the fitting hole 10 and the fitting piece 11 are respectively tapered frustoconical tapered surfaces. A chamfered portion 12 A for facilitating insertion of the hook piece 13 is formed in the insertion hole 12. The flange 6 is formed with a through-hole 6A that enables movement of the piece when the hook piece 13 is formed.
[0017]
 As described above, in the pulley having the substantially trapezoidal belt engagement groove 4 on the outer peripheral portion, the inner surfaces of the flanges 5 and 6 are tapered so that the belt engagement groove 4 has a substantially trapezoidal shape. Therefore, if the centers of the two split pieces 2A and 2B are shifted and joined, the side surface of the belt does not fit the inner side surface of the flange portions 5 and 6 when the belt is put on the belt engaging groove 4, The belt rotation is distorted, which causes squeak noise and uneven wear. However, in the above embodiment, as described above, since the fitting surface of the fitting hole 10 and the fitting piece 11 is a tapered surface, when the two divided pieces 2A and 2B are joined, the two divided pieces 2A, 2B can be easily centered. In addition, since the fitting hole 10 and the fitting piece 11 can be reliably fitted in a close contact state, concentric coupling without play in the radial direction can be obtained with certainty. Further, since the hook piece 13 can be locked to the end edge of the insertion hole 12 when the fitting hole 10 and the fitting piece 11 are fitted, the separation of the two divided pieces 2A and 2B coupled to each other is ensured. Can be prevented.
[0018]
 In the illustrated embodiment, the claw portion 13A at the tip of the hook piece 13 to be engaged with the end edge of the insertion hole 12 protrudes outward in the radial direction of the split pieces 2A and 2B. You may protrude in the direction perpendicular to the direction.
[0019]
 Furthermore, in the said Example, the dimension is set so that the hook piece 13 may be latched by the edge of the insertion hole 12 in the state in which the fitting piece 11 was press-fit in the fitting hole 10. FIG. Therefore, the two split pieces 2A and 2B can be strongly coupled by press-fitting the fitting piece 11 into the fitting hole 10. Further, since the relative position in the axial direction of both divided pieces 2A and 2B can be adjusted by adjusting the tightening allowance between the fitting hole 10 and the fitting piece 11 when the divided pieces 2A and 2B are joined, the hook pieces 13 can be securely locked to the end edge of the insertion hole 12 without any play in the axial direction.
[0020]
 Furthermore, in the said Example, since the fitting part of the fitting hole 10 and the fitting piece 11 is formed in the outer peripheral part side of division piece 2A, 2B rather than the insertion hole 12 and the hook piece 13, division piece The radius of curvature of the fitting portion between the fitting hole 10 and the fitting piece 11 having the center of curvature on the rotation axis of 2A and 2B can be increased. Therefore, the alignment accuracy between the fitting hole 10 and the fitting piece 11 can be easily increased. In addition, since the fitting portion between the fitting hole 10 and the fitting piece 11 can be aligned with the outer peripheral portion of the two split pieces 2A and 2B, the belt engaging groove formed in the outer peripheral portion of the pulley can be obtained. The alignment accuracy of the two split pieces 2A and 2B at the four locations can be increased.
[0021]
 Furthermore, in the said Example, the edge of the penetration hole 12 with which the hook piece 13 is latched was formed in the end surface of the division piece 2A on the opposite side to the division piece 2B which has the hook piece 13With a circular cross-section (see Figure 1)Since it is formed in the bottom face part of the recessed part 14, the front-end | tip part of the hook piece 12 latched by the edge of the penetration hole 12 can be arrange | positioned in the recessed part 14 formed in the end surface of 2 A of division pieces. The tip of the hook piece 13 can be prevented from protruding from the end face of the split piece 2A.
[0022]
 It should be noted that the detents of both the split pieces 2A and 2B are the frictional coupling by press-fitting the fitting piece 11 into the fitting hole 10, and the wall surface of the insertion hole 12 and the side surface of the hook piece 13 inserted through the insertion hole 12. Although it may be achieved by contact, as in the illustrated embodiment, a D-cut portion 3A is formed on the outer peripheral surface of the hub 3 of one divided piece 2A, and the center hole 9 of the other divided piece 2B is formed in this D-cut. If it is adapted to the part 3A, a more reliable detent can be achieved.
[0023]
 Furthermore, the inclination angle of the fitting surface of the fitting hole 10 and the fitting piece 11 is set in consideration of workability when connecting the two divided pieces 2A and 2B and the alignment accuracy of the divided pieces 2A and 2B. Should.
[0024]
 3 to 5 show a second embodiment of the present invention. The transmission rotating body 20 in the transmission rotating body of the second embodiment includes a hub 21, a small gear portion 22 having a tooth profile 23 on the outer peripheral portion, and a tooth profile 25 having a tip diameter larger than that of the small gear portion 22. The large gear portion 24 having the cam surface 27 and the cam portion 26 having the cam surface 27 on the outer peripheral portion are integrated, and the large gear portion 24 and the cam portion 26 are respectively arranged on both sides of the small gear portion 22. Yes. Therefore, in this type of transmission rotating body, a substantially concave recess in the axial direction is formed over the entire circumference on the outer peripheral portion of the transmission rotating body main body 20 with the position of the tooth profile 23 of the small gear portion 22 as the bottom surface portion. Therefore, when the transmission rotor main body 20 is to be integrally formed of synthetic resin, it is necessary to dispose a large number of pieces for forming the tooth profile 23 of the small gear portion 22 on the mold so as to be radially movable.
[0025]
 Therefore, in the second embodiment of the present invention, the transmission rotating body 20 is composed of two divided pieces 20A and 20B, and one divided piece 20A is formed by integrating the hub 21, the small gear portion 22, and the large gear portion 24 together. The other divided piece 20 B has a cam portion 26. The small gear portion 22 and the large gear portion 24 in one divided piece 20 A have a substantially ring shape, and are connected to the hub 21 via a disk-shaped connecting wall portion 28. Since the outer peripheral portion of the transmission rotor body 20 has a concave portion having a substantially concave cross section in the axial direction, and the tooth profile 23 of the small gear portion 22 forms the bottom surface portion of the concave portion, both divided pieces 20A and 20B are formed on the bottom surface of the concave portion. This is divided at the boundary between the tooth profile 23 of the small gear 22 and the cam portion 26. A central hole 29 is formed in the central portion of the other divided piece 20B having the cam portion 26 so as to be fitted to the hub 3 with an appropriate clearance.
[0026]
 Further, a fitting hole 30 having a circular cross section having a center of curvature is formed on the rotation axis of the divided piece 20A on the inner side of the small gear portion 22 of one divided piece 20A, and the other divided piece 20B has the A fitting piece 31 that fits into the fitting hole 30 is provided. In addition, a plurality (three in the illustrated embodiment) of insertion holes 32 are formed in the connecting wall portion 28 of one divided piece 20A at equal angular intervals in the circumferential direction, and each of the divided pieces 20B has a respective one. A plurality of hook pieces 33 that are inserted through the insertion holes 32 and locked to the end edges of the insertion holes 32 so as to be prevented from coming off in the axial direction are provided. The fitting surfaces of the fitting hole 30 and the fitting piece 31 are respectively tapered frustoconical tapered surfaces.
[0027]
 In the said 2nd Example, since the fitting surface of the fitting hole 30 and the fitting piece 31 is made into the taper surface, when connecting both the division pieces 20A and 20B, both division pieces 20A and 20B are used. It can be easily aligned. In addition, since the fitting hole 30 and the fitting piece 31 can be reliably fitted in a close contact state, concentric coupling that does not cause play in the radial direction can be reliably obtained. Further, since the hook piece 33 can be locked to the edge of the insertion hole 32 when the fitting hole 30 and the fitting piece 31 are fitted, the two divided pieces 20A and 20B coupled to each other can be surely detached. Can be prevented.
[0028]
 In the second embodiment as well, the claw portion 33A at the tip of the hook piece 33 that is locked to the edge of the insertion hole 32 protrudes outward in the radial direction of the split pieces 20A and 20B. Or you may protrude in the direction orthogonal to a radial direction.
[0029]
 Further, in the second embodiment, the dimension is set so that the hook piece 33 is locked to the edge of the insertion hole 32 in a state where the fitting piece 31 is press-fitted into the fitting hole 30. Therefore, both the split pieces 20A and 20B can be strongly coupled by press-fitting the fitting piece 31 into the fitting hole 30. In addition, since the relative position in the axial direction of both the split pieces 20A and 20B can be adjusted by adjusting the tightening allowance between the fitting hole 30 and the fitting piece 31 when the split pieces 20A and 20B are joined, the hook pieces 33 can be securely locked to the end edge of the insertion hole 32 without any play in the axial direction.
[0030]
 Further, also in the second embodiment, the fitting portion between the fitting hole 30 and the fitting piece 31 is formed on the outer peripheral side of the divided pieces 20A and 20B rather than the insertion hole 32 and the hook piece 33. The radius of curvature of the fitting portion between the fitting hole 30 having the center of curvature and the fitting piece 31 on the rotation axis of the divided pieces 20A and 20B can be increased. Therefore, the alignment accuracy between the fitting hole 30 and the fitting piece 31 can be easily increased. In addition, since the fitting portion between the fitting hole 30 and the fitting piece 31 can be brought close to the outer peripheral portion of both the split pieces 20A and 20B, the centering can be performed at the outer peripheral portion of both the split pieces 20A and 20B. Accuracy can be increased.
[0031]
 Further, also in the second embodiment, the end edge of the insertion hole 32 to which the hook piece 33 is locked is formed on the end surface of the divided piece 20A opposite to the divided piece 20B having the hook piece 33.Circular cross section (see Fig. 3)Therefore, the tip of the hook piece 33 locked to the end edge of the insertion hole 32 can be disposed in the recessed portion 34 formed on the end face of the divided piece 20A. It is possible to prevent the tip of the hook piece 33 from protruding from the end face of the divided piece 20A.
[0032]
 In the second embodiment, the detents of both the split pieces 20A and 20B are inserted through the frictional coupling by press-fitting the fitting piece 31 into the fitting hole 30, the wall surface of the insertion hole 32, and the insertion hole 32. This is achieved by contact with the side surface of the hook piece 33. As in the first embodiment, a D-cut portion is formed on the outer peripheral surface of the hub 21 of one divided piece 20A, and the center hole of the other divided piece 20B is formed. If 29 is adapted to this D-cut portion, a more reliable detent can be achieved.
[0033]
 6 and 7 show a third embodiment of the present invention. The transmission rotor main body 40 in the transmission rotor of the third embodiment is an integrated hub 41 and three cam portions 42, 44, 46 each provided with cam surfaces 43, 45, 47 on the outer periphery. is there. Accordingly, in this type of transmission rotating body, the outer peripheral portion of the transmission rotating body main body 40 as shown in FIG. 7 due to the uneven shape of the cam surfaces 43, 45, 47 on the outer peripheral portions of the cam portions 42, 44, 46. Is partially formed with a recess having a substantially concave cross section in the axial direction. For this reason, when the transmission rotor main body 40 is to be integrally formed of synthetic resin, it is necessary to displace a plurality of pieces for forming the outer peripheral cam surface 43 of the intermediate cam portion 42 in the mold. .
[0034]
 Therefore, in the third embodiment of the present invention, the transmission rotor body 40 is composed of two divided pieces 40A and 40B, and one divided piece 40A is a hub 41, an intermediate cam portion 42, and a cam positioned on one side thereof. The other divided piece 40B has a cam portion 46 on the other side. The two cam portions 42, 44 in one divided piece 40 A have a substantially ring shape, and are connected to the hub 41 via a disk-like connecting wall portion 48. Both divided pieces 40A and 40B are divided at a boundary portion between the intermediate cam portion 42 and the cam portion 46 on the other side (lower side in FIG. 7). A central hole 49 is formed in the central portion of the other divided piece 40B having the cam portion 46 so as to be fitted to the hub 41 with an appropriate clearance.
[0035]
 Furthermore, a fitting hole 50 having a circular cross section having a center of curvature is formed on the rotation axis of the divided piece 40A on the inner side of the intermediate cam portion 42 in one divided piece 40A, and the other divided piece 40B has A fitting piece 51 that fits into the fitting hole 50 is provided. In addition, a plurality (three in the illustrated embodiment) of insertion holes 52 are formed in the connecting wall portion 48 of one divided piece 40A at equal angular intervals in the circumferential direction, and each of the divided pieces 40B has a respective one. A plurality of hook pieces 53 that are inserted into the insertion hole 52 and locked to the edge of the insertion hole 52 so as to be prevented from coming off in the axial direction are provided. The fitting surfaces of the fitting hole 50 and the fitting piece 51 are respectively tapered frustoconical tapered surfaces.
[0036]
 In the said 3rd Example, since the fitting surface of the fitting hole 50 and the fitting piece 51 is made into the taper surface, when joining both the division pieces 40A and 40B, both division pieces 40A and 40B are used. It can be easily aligned. Further, since the fitting hole 50 and the fitting piece 51 can be reliably fitted in a close contact state, a concentric coupling without play in the radial direction can be obtained with certainty. Further, since the hook piece 53 can be locked to the edge of the insertion hole 52 when the fitting hole 50 and the fitting piece 51 are fitted, the two divided pieces 40A and 40B coupled to each other can be surely detached. Can be prevented.
[0037]
 In the third embodiment as well, the claw portion 53A at the tip of the hook piece 53 that is locked to the edge of the insertion hole 52 protrudes outward in the radial direction of the split pieces 40A and 40B. Or you may protrude in the direction orthogonal to a radial direction.
[0038]
 Further, also in the third embodiment, the dimension is set so that the hook piece 53 is locked to the edge of the insertion hole 52 in a state where the fitting piece 51 is press-fitted into the fitting hole 50. Therefore, both the split pieces 40A and 40B can be strongly coupled by press-fitting the fitting piece 51 into the fitting hole 50. Further, since the relative position in the axial direction of both the split pieces 40A and 40B can be adjusted by adjusting the tightening allowance between the fitting hole 50 and the fitting piece 51 when the split pieces 40A and 40B are joined, the hook pieces 53 can be securely locked to the end edge of the insertion hole 52 with no play in the axial direction.
[0039]
 Furthermore, also in the third embodiment, the fitting portion between the fitting hole 50 and the fitting piece 51 is formed on the outer peripheral side of the divided pieces 40A and 40B rather than the insertion hole 52 and the hook piece 53. The curvature radius of the fitting portion between the fitting hole 50 and the fitting piece 51 having the center of curvature on the rotation axis of the divided pieces 40A and 40B can be increased. Therefore, the alignment accuracy between the fitting hole 50 and the fitting piece 51 can be easily increased. In addition, since the fitting portion between the fitting hole 50 and the fitting piece 51 can be brought close to the outer peripheral portion of both the split pieces 40A and 40B, the centering can be performed at the outer peripheral portion of both the split pieces 40A and 40B. Accuracy can be increased.
[0040]
 Further, also in the third embodiment, the end edge of the insertion hole 52 to which the hook piece 53 is locked is formed on the end surface of the divided piece 40A opposite to the divided piece 40B having the hook piece 53.With a circular cross-section (see Fig. 6)Since it is formed in the bottom face part of the recessed part 54, the front-end | tip part of the hook piece 53 latched by the edge of the penetration hole 52 can be arrange | positioned in the recessed part 54 formed in the end surface of the division piece 40A. The tip of the hook piece 53 can be prevented from protruding from the end face of the divided piece 40A.
[0041]
 In the third embodiment, similarly to the second embodiment, the rotation of both the split pieces 40A and 40B is caused by frictional coupling by press-fitting the fitting piece 51 into the fitting hole 50, and the wall surface of the insertion hole 52. This is achieved by contact with the side surface of the hook piece 53 inserted through the insertion hole 52. As in the first embodiment, a D-cut portion is formed on the outer peripheral surface of the hub 41 of one divided piece 40A. If the center hole 49 of the other divided piece 40B is adapted to this D-cut portion, a more reliable detent can be achieved.
[0042]
 FIG. 8 shows a fourth embodiment of the present invention. The transmission rotor main body 40 in the transmission rotor of the fourth embodiment has a hub 41 and five cam portions 42, 44, 46, 54 each having cam surfaces 43, 45, 47, 55, 57 on the outer periphery. , 56 are integrated. Accordingly, in this type of transmission rotating body, the cam portions 44, 46, 54, 56, and the cam portions 46, 46, 54, 56 are formed by the uneven shapes of the cam surfaces 43, 45, 47, 55, 57 on the outer periphery. A recess having a substantially concave cross section in the axial direction is partially formed on the outer periphery of the transmission rotor body 40 between the cam portion 44 and the cam portion 56. A concave portion having a substantially concave axial cross section is partially formed. For this reason, when the transmission rotor main body 40 is formed integrally with synthetic resin, a plurality of pieces for forming the outer peripheral cam surface 43 of the cam portion 42 and the outer peripheral cam surface 55 of the cam portion 54 are formed on the mold. It is necessary to arrange a plurality of pieces to be movable.
[0043]
 Therefore, in the fourth embodiment of the present invention, the transmission rotor main body 40 is composed of three divided pieces 40A, 40B, 40C, and the relationship between the adjacent two divided pieces 40A, 40B is the same as in the third embodiment. Further, the relationship between the two adjacent divided pieces 40A and 40C is the same as the relationship between the divided pieces 40A and 40B.
[0044]
 That is, the intermediate divided piece 40A has the hub 41 and the cam portions 42, 44, 54 integrally, the one divided piece 40B has the cam portion 46, and the other divided piece 40C has the cam portion 56. doing. The two cam portions 42, 44, 54 in the intermediate divided piece 40 A have a substantially ring shape, and are connected to the hub 41 via a disk-shaped connecting wall portion 48. The relationship between the two divided pieces 40A and 40B is the same as that in the third embodiment, and the same reference numerals are assigned to the same components. Accordingly, detailed description of the relationship between the two divided pieces 40A and 40B is omitted here.
[0045]
 In the relationship between two adjacent divided pieces 40A and 40C, both divided pieces 40A and 40C are divided at the boundary between the cam portion 54 of the divided piece 40A and the cam portion 56 of the divided piece 40C. A central hole 59 that fits with the hub 41 is formed at a central portion of the split piece 40C having the cam portion 56 with an appropriate clearance.
[0046]
 Further, a fitting hole 60 having a circular cross section having a center of curvature is formed on the rotation axis of the divided piece 40A on the inner side of the cam portions 44 and 54 of the divided piece 40A, and the fitting is made on the other divided piece 40C. A fitting piece 61 that fits into the fitting hole 60 is provided. A plurality of insertion holes 62 are formed in the connecting wall portion 48 of one divided piece 40A at equal angular intervals in the circumferential direction, and the other divided piece 40C is inserted into each insertion hole 62 and A plurality of hook pieces 63 are provided at the edge of the insertion hole 62 so as to be locked so as to be prevented from coming off in the axial direction. The fitting surfaces of the fitting hole 60 and the fitting piece 61 are respectively tapered frustoconical tapered surfaces.
[0047]
 Further, since the fitting surface of the fitting hole 60 and the fitting piece 61 is a tapered surface, when the two adjacent divided pieces 40A and 40C are joined, the two divided pieces 40A and 40C can be easily centered. Can be combined. In addition, since the fitting hole 60 and the fitting piece 61 can be reliably fitted in a close contact state, concentric coupling without play in the radial direction can be obtained with certainty. Furthermore, since the hook piece 63 can be locked to the edge of the insertion hole 62 when the fitting hole 60 and the fitting piece 61 are fitted, the two divided pieces 40A and 40C coupled to each other can be reliably detached. Can be prevented.
[0048]
 Further, in the relationship between the two divided pieces 40A and 49C, the dimension is set so that the hook piece 63 is locked to the edge of the insertion hole 62 in a state where the fitting piece 61 is press-fitted into the fitting hole 60. Therefore, both the split pieces 40 A and 40 C can be strongly coupled by press-fitting the fitting piece 61 into the fitting hole 60. In addition, since the relative position in the axial direction of both divided pieces 40A and 40C can be adjusted by adjusting the tightening allowance between the fitting hole 60 and the fitting piece 61 when the divided pieces 40A and 40C are coupled, the hook pieces 63 can be securely locked to the end edge of the insertion hole 62 without any play in the axial direction.
[0049]
 FIG. 9 shows a modification of the first embodiment shown in FIGS. In the figure, the same reference numerals are assigned to the same components as those of the first embodiment. In this modification, a tapered fitting hole 9 'having a circular cross section having a center of curvature is formed on the rotation axis of the divided piece 2B, and the fitting hole 9' is formed in the hub 3 of the divided piece 2A. A fitting portion 10 ′ to be fitted is provided. Therefore, also in this modified example, the two split pieces 2A and 2B can be reliably concentrically coupled by fitting the fitting hole 9 'and the fitting portion 10'. Further, since the hook piece 12 can be locked to the end edge of the insertion hole 11 when the fitting hole 9 ′ and the fitting portion 10 ′ are fitted, the two separated pieces 2A and 2B coupled to each other can be detached. Can be reliably prevented.
[0050]
 Although the illustrated embodiment has been described above, the present invention is not limited only to the embodiment described above, and various modifications can be made to the components within the scope of the invention described in the claims.it can.
[0051]
 For example,The fitting hole and the fitting piece may be arranged and formed closer to the rotation axis of the divided piece than the insertion hole and the hook piece. Therefore, for example, a fitting hole and a fitting piece may be arranged between the insertion hole and the hook piece and the hub, respectively.
[0052]
 Also hook pieceAlthough the number of is preferably plural, it may be one.
[0053]
 further,The split piece may be provided with a shaft portion having a solid structure in place of the hub at the center thereof.
[0054]
 Also,The present invention can be applied to a transmission rotating body integrated with any combination of a plurality of pulleys or gears, sprockets, pulleys, cams, etc. in addition to the combinations of gears and cams shown in the above embodiments. is there.
[0055]
 AlsoIn general, in the case of a transmission rotating body, there are many cases where the temperature becomes high due to frictional heat generated by the rotation, etc. Therefore, each divided piece is preferably made of the same synthetic resin material or a synthetic resin material having an approximate linear expansion coefficient. .
[0056]
【The invention's effect】
 As is clear from the above description, the present inventionIn a transmission rotating body having a recess having a substantially concave cross section in the axial direction on at least a part of an outer peripheral portion of a rotating body body made of synthetic resin, the rotating body body is divided at a boundary portion between a bottom surface portion and an inner surface of the recess. In addition, one of the two divided pieces adjacent to each other has a circular fitting hole with a circular cross section having a center of curvature on the rotation axis, and the other of the two divided pieces adjacent to each other. Each of the divided pieces is provided with a fitting piece that fits into the fitting hole. On the other end surface side of the one divided piece, a concave section having a circular cross section having a center of curvature is formed on the rotation axis. A disk-shaped connecting wall portion is formed between the recessed portion and the fitting piece, and an insertion hole penetrating between the fitting hole and the recessed portion is formed in the connecting wall portion, and the other divided piece. Is inserted through the insertion hole and can be prevented from coming off in the axial direction at the edge of the insertion hole on the bottom surface of the recessed portion. The hook piece is provided in a state in which the fitting hole and the fitting surface of the fitting piece are tapered surfaces, and the hook piece is pressed into the fitting hole. It is comprised so that it may be latched by the edge of the said insertion hole on the bottom face of the said recessed part.Therefore, it is possible to provide a transmission rotor having a strong coupling structure that is easy to manufacture and does not generate play in the radial direction and the axial direction.
 Further, the present invention provides a transmission rotating body having a recess whose axial cross section is substantially concave in at least a part of an outer peripheral portion of a rotating body body made of synthetic resin, wherein the rotating body body includes a bottom surface portion and an inner surface of the recess. Of the three divided pieces, each having a circular cross section having a center of curvature on the rotation axis on one end surface side and the other end surface side of the intermediate divided piece of the three divided pieces, respectively. A fitting hole is formed to form a disk-shaped connecting wall between the fitting holes, and one of the other two divided pieces has a fitting hole on the one end face side of the intermediate divided piece. A fitting piece to be fitted is provided on the other side, and a fitting piece to be fitted with the fitting hole on the other end surface side of the intermediate divided piece is provided on the other side. A plurality of insertion holes penetrating between the fitting holes are formed, and the other two divided pieces are inserted into the insertion holes. Hook pieces that are locked at the end edges of the insertion holes so as to be prevented from coming off in the axial direction are provided, the fitting surfaces of the fitting holes and the fitting pieces are tapered surfaces, respectively. Since the hook piece is configured to be locked to the end edge of the insertion hole while being press-fitted into the fitting hole, it is easy to manufacture and does not cause play in the radial direction and the axial direction. It is possible to provide a transmission rotor of a three-piece type with a simple coupling structure.
[Brief description of the drawings]
FIG. 1 is a plan view of a pulley showing a first embodiment of the present invention.
2 is a cross-sectional view of the pulley shown in FIG. 1 taken along line AA in FIG.
FIG. 3 is a plan view of a transmission rotating body in which two gears and a cam are integrated in a second embodiment of the present invention.
4 is a cross-sectional view of the transmission rotating body shown in FIG. 3 taken along line BB in FIG. 3;
5 is a bottom view of the transmission rotating body shown in FIG. 3. FIG.
FIG. 6 is a plan view of a transmission rotating body in which three cams according to a third embodiment of the present invention are integrated.
7 is a cross-sectional view of the transmission rotating body shown in FIG. 6 taken along the line CC in FIG. 6;
8 is a cross-sectional view similar to FIG. 7 of a transmission rotating body in which five cams are integrated, showing a fourth embodiment of the present invention.
9 is a cross-sectional view similar to FIG. 2 of a pulley showing a modification of the first embodiment shown in FIGS. 1 and 2. FIG.
[Explanation of symbols]
2 Pulley (transmission rotor)
2A, 2B split pieces
3 Hub
4 Belt engagement groove
5,6 Flange
7 Rim
8 Connecting wall
10 Mating hole
11 Mating piece
12 Insertion hole
13 Hook pieces

Claims

In a transmission rotating body having a recess having a substantially concave cross section in the axial direction on at least a part of an outer peripheral portion of a rotating body body made of synthetic resin, the rotating body body is divided at a boundary portion between a bottom surface portion and an inner surface of the recess. composed of a plurality of divided pieces, the circular cross section of the fitting hole in one end face of one of the divided pieces of the adjacent two divided pieces to each other with a center of curvature on the axis of rotation, and the other Each of the divided pieces is provided with a fitting piece that fits into the fitting hole. On the other end surface side of the one divided piece, a concave section having a circular cross section having a center of curvature is formed on the rotation axis. A disk-shaped connecting wall portion is formed between the recessed portion and the fitting piece, and an insertion hole penetrating between the fitting hole and the recessed portion is formed in the connecting wall portion, and the other divided piece. Is inserted through the insertion hole and can be prevented from coming off in the axial direction at the edge of the insertion hole on the bottom surface of the recessed portion. Hooks to be engaged is provided on the fitting surface of the said fitting hole fitting tab is respectively tapered surface, the hooks in a state in which the fitting piece is press-fitted into the fitting hole A transmission rotating body that is locked to an edge of the insertion hole.

2. The transmission rotating body according to claim 1, wherein a fitting portion between the fitting hole and the fitting piece is formed closer to an outer peripheral portion side of the split piece than the insertion hole and the hook piece.

In a transmission rotating body having a recess having a substantially concave cross section in the axial direction on at least a part of an outer peripheral portion of a rotating body body made of synthetic resin, the rotating body body is divided at a boundary portion between a bottom surface portion and an inner surface of the recess. Each of the three divided pieces is formed with a fitting hole having a circular cross section having a center of curvature on the axis of rotation on one end surface side and the other end surface side of the intermediate divided piece. A disc-shaped connecting wall portion is formed between the two fitting holes, and one of the other two divided pieces is a fitting piece that fits into the fitting hole on the one end face side of the intermediate divided piece. However, the other is provided with a fitting piece that fits into the fitting hole on the other end surface side of the intermediate divided piece, and penetrates between the fitting holes in the connecting wall portion of the intermediate divided piece. A plurality of insertion holes are formed, and the other two divided pieces are inserted into the insertion holes and end edges of the insertion holes Hook pieces that are locked so as to be prevented from coming off in the axial direction are provided, the fitting surfaces of the fitting holes and the fitting pieces are tapered surfaces, and the fitting pieces are press-fitted into the fitting holes. The transmission rotating body , wherein the hook piece is locked to an end edge of the insertion hole in a state .