JP3838819B2 - Toothed belt, toothed belt transmission and office equipment - Google Patents

Toothed belt, toothed belt transmission and office equipment Download PDF

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JP3838819B2
JP3838819B2 JP18055399A JP18055399A JP3838819B2 JP 3838819 B2 JP3838819 B2 JP 3838819B2 JP 18055399 A JP18055399 A JP 18055399A JP 18055399 A JP18055399 A JP 18055399A JP 3838819 B2 JP3838819 B2 JP 3838819B2
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pulley
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政喜 落合
隆一 城戸
英昭 川原
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Bando Chemical Industries Ltd
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Description

【０００１】
【発明の属する技術分野】
本発明は、歯付ベルト及び歯付ベルト伝動装置並びにそれを用いた事務用機器に関し、特に、ベルトの速度むら（速度変動）を低減させるための技術分野に属するものである。
【０００２】
【従来の技術】
従来より、この種の歯付ベルトとしては、ベルト歯部の形状が台形状であるものが一般的に用いられていたが、より一層の高負荷を伝達したり、騒音をより一層低減したりするという目的で、凸形状の側面を有する歯部形状のベルトが提案され、現在では主流となっている。その歯形の１つが特開昭５０―４２２５２号公報に示されるいわゆるＳＴＰＤ歯形と呼ばれるものであり、他の１つが特開昭５９―８９８５２号公報に示されたいわゆるＨＴＤ−II歯形と呼ばれるものである。前者のＳＴＰＤ歯形は、例えばバンドー化学（株）の商品名「スーパートルクシンクロベルト」として、また後者のＨＴＤ−II歯形は、ユニッタ（株）の商品名「パワーグリップＧＴベルト」としてそれぞれ実用化されている。
【０００３】
また、この他、事務用機器における可動部の精密な位置決め駆動を目的として、特開昭６４―７４３４１号公報に示される歯付ベルトも提案されている。このものでは、図２１に示すように、ベルト１０′における本体１１′のランドラインＬＬ上に複数のベルト歯部１３′，１３′，…（１つのみ示す）を一定ピッチで設け、この各ベルト歯部１３′は、歯幅方向中心線Ｃ２に対し対称に配置された円弧面からなる歯元部１４′，１４′と、この歯元部１４′，１４′に連続してかつ上記歯幅方向中心線Ｃ２に対し対称に設けられた凸形状の円弧面からなる歯側面部１５′，１５′と、この歯側面部１５′，１５′に連続してかつ上記歯幅方向中心線Ｃ２に対し対称に設けられた円弧面からなる円弧面部１７′，１７′とを備え、これら円弧面部１７′，１７′同士は１つの平面からなる平面部１８′により接続されている。そして、この歯付ベルト１０′の歯付プーリ１′との静的噛合い状態において、各ベルト歯部１３′の歯元部１４′がプーリ歯溝部３′の歯頂円弧部４′と略接触し、ベルト歯部１３′のプーリ歯溝部３′でのバックラッシュがベルト歯部１３′の歯元から歯先にかけて漸次増大し、プーリ歯溝部３′の深さがベルト歯部１３′の高さ以上になるように構成されている。
【０００４】
このものでは、プーリ歯溝部３′とのバックラッシュをベルト歯部１３′の歯元部１４′でなくす一方、そのプーリ歯溝部３′とのバックラッシュをベルト歯部１３′の歯元から歯先にかけて漸増させてベルト歯部１３′を歯先に向かって細くし、このことでベルト歯部１３′とプーリ歯溝部３′の歯頂円弧部４′との噛合い干渉を抑制して、この噛合い干渉に起因するベルトピッチラインＰＬの変動を低減するようにしている。尚、図２１中、５′はプーリ歯溝部３′における凹形状の歯溝側面部、６′は歯溝底部である。また、ベルト１０′のピッチラインＰＬはプーリ１′のピッチ円ＰＣと一致している。また、理解を容易にするために、図２１ではプーリ１′の外周部をベルト１０′と共に展開して示している。
【０００５】
【発明が解決しようとする課題】
ところで、プリンタや複写機に代表される事務用機器においては、歯付ベルト伝動装置を利用した印字装置（画像印刷も含む）が一般的に用いられている。この印字装置では、インクやハンマ等の印字機構を装着したキャリッジを歯付ベルトに取り付けて、この歯付ベルトを歯付プーリ間に掛け渡し、プーリを正逆転させてキャリッジを往復動作させるようになっている。
【０００６】
そして、上記キャリッジによる印字精度や画像品質を高めるために、歯付ベルトの走行時の速度むら（速度変動）を可能な限り低減することが要求される。特に、プリンタにおいては、近年、カラー印刷やその高速化・高画質化が急速に進んでおり、歯付ベルトの噛合振動（噛合いによる速度むら）が印字むらや画像むらを引き起こすことがあるので、歯付ベルトの噛合速度むらの低減が強く要求されている。
【０００７】
これらプリンタ等の事務用機器には、上記ＳＴＰＤ歯形やＨＴＤ−ＩＩ歯形で歯部ピッチが３ｍｍ以下（例えば３ｍｍ、２ｍｍ、１．５ｍｍ等）の歯付ベルトが一般的に用いられており、その歯部の形状は８ｍｍピッチや５ｍｍピッチ等、比較的大きい歯部ピッチの歯形をそのまま略相似的に縮小した形状が採用されている。
【０００８】
しかしながら、これらの歯形は本来、高負荷伝達の用途を目的として開発されたものであり、このため、上記速度むらを低減する要求については何等考慮されていない。
【０００９】
尚、上記した特開昭６４―７４３４１号公報に示される歯付ベルトは、速度むらの低減をある程度考慮して提案されたものではあるが、その速度むらの低減に最適な歯形とはなり得ておらず、速度むらを可及的に低減するのに不十分であった。
【００１０】
すなわち、このように、歯付ベルトの速度むら低減のための歯形状の研究等については、従来から殆ど行われていないのが実情である。
【００１１】
本発明は斯かる諸点に鑑み、本発明者が上記の如き事務用機器等に用いられる歯付ベルトの歯形状を構成する種々の因子について解析及び実験を鋭意重ねることでなされたものであり、その目的は歯付ベルトの速度むらを可及的に低減することにある。
【００１２】
【課題を解決するための手段】
上記の目的を達成するために、本発明者による研究の結果、これまでに全く考慮されていなかった因子として、ベルト歯部の側面を凸形状とした歯付ベルトにおいては、その側面の所定位置での圧力角が速度むらに極めて大きな影響を与えることが突き止められた。上記圧力角とは、ベルトのランドライン上での歯元幅をＷとしたとき、ランドラインから歯高さ方向に０．３Ｗ離れた位置（この位置を基準位置とする）におけるベルト歯部側面の圧力角であり、以後、「０．３Ｗ圧力角」とも記す。この理由は、ベルト歯部側面の凸形状の歯側面部が通常０．６Ｗ前後の歯高さを有するので、その歯高さの中央となる基準位置での「０．３Ｗ圧力角」が凸形状歯形の圧力角として実質的に有効な指標となるからである。
【００１３】
従来のＳＴＰＤ歯形やＨＴＤ−II歯形を有する歯付ベルトでは、高負荷伝動を目的としているので、高負荷時のベルトの歯飛び（ジャンピング）を避けるために、歯部側面の上記０．３Ｗ圧力角は小さく設定される。例えば歯部ピッチが１．５〜３．０ｍｍのＳＴＰＤ歯形では上記０．３Ｗ圧力角は２５．１〜２５．３°の範囲に、また１．５〜３．０ｍｍピッチのＨＴＤ−ＩＩ歯形では０．３Ｗ圧力角は２０．８〜２１．１°の範囲にそれぞれ設定されている。これに対し、事務用機器の用途に用いられる歯付ベルトは、軽負荷伝動条件下で駆動されるものであるので、上記の如きベルトの歯飛びを考慮する必要は殆どない。そして、発明者の研究の結果、歯部側面の０．３Ｗ圧力角を２６〜３９°とすることで、ベルトの速度むらを大きく低減できることが判明した。
【００１４】
具体的には、請求項１の発明では、軽負荷伝動用の歯付ベルトとして、ピッチライン上に抗張体が埋設されたベルト本体と、このベルト本体のランドライン上に一定ピッチで設けられた複数のベルト歯部とを備えている。そして、上記各ベルト歯部は、歯幅方向中心線に対し対称に配置された略円弧面からなる歯元部と、この歯元部に連続して歯部側面に位置しかつ上記歯幅方向中心線に対し対称に設けられた凸形状の略円弧面からなる歯側面部と、この両歯側面部の円弧面の歯先側延長線よりも歯元側に位置し、両歯側面部同士を連続するように設けられた歯先部とで構成され、上記ランドライン上での歯元幅をＷとしたとき、上記ベルト歯部の歯側面部においてランドラインから歯高さ方向に０．３Ｗ離れた基準位置での圧力角（０．３Ｗ圧力角）が２６〜３９°であり、上記歯側面部と略相似形でかつ張力の付与された伝動状態において、該歯側面部と歯高さ方向の各位置での圧力角が略等しい歯溝側面部を有する複数のプーリ歯溝部がプーリ外径ライン上に一定ピッチで設けられた歯付プーリに巻き付けられることを特徴としている。
【００１５】
歯付ベルトの歯部が駆動側の歯付プーリの歯溝部に噛み込むとき、与えられる負荷トルクの影響によりベルト歯部はプーリ歯溝部の位置に対し若干遅れた位置で噛み込むので、まず、ベルト歯部の走行方向後側の歯部側面がプーリ歯溝部の側面に接触し、その後にベルト歯部がプーリ歯溝部に滑り込む。このとき、ベルトのスパン（プーリに巻き付いていない部分）でベルトピッチラインがベルトスパンと直交する方向に上下動することにより、噛合い速度むらが発生する。上記ピッチラインの上下動量は、ベルト歯部がプーリ歯溝部に滑り込む際に発生する反力と、その反力によってベルトが上側に押し上げられたときに発生するベルト張力の分力とによって決まる。このため、接触位置がベルト歯部とプーリ歯溝部との完全噛合位置から離れるほどベルト張力の分力が小さくなり、ピッチラインの押上げ量が大きくなる。換言すれば、ベルト歯部のプーリ歯溝部への接触が早期になされるほど速度むらが大きくなるのである。
【００１６】
それ故、従来の歯部形状のように０．３Ｗ圧力角が小さいと、ベルト歯部の側面がプーリ歯溝部の側面に早く接触する（図４（ｂ）参照）のに対し、本発明のように０．３Ｗ圧力角が従来のものよりも大きいと、ベルト歯部のプーリ歯溝部側面との接触は遅くなり（図４（ａ）参照）、このことによってベルトの速度むらを低減することができる。
【００１７】
一方、上記０．３Ｗ圧力角を無闇に大きくすることはできず、それが大き過ぎると、却って速度むらが増大する。すなわち、上記のとおり、ベルト歯部の側面はプーリ歯溝部の側面と接触した後に滑り込む反力とベルト張力の分力とによってベルトスパンの移動量が決まるが、そのとき、０．３Ｗ圧力角が大き過ぎると、ベルト歯部がプーリ歯溝部に滑り込む際に発生する反力の垂直方向（ベルトスパンと直交する方向）の成分が大きくなり過ぎ、容易に滑り込めなくなってベルトピッチラインが押し上げられるためである。
【００１８】
したがって、上記０．３Ｗ圧力角は、本発明者の解析結果によれば、上記の如く２６〜３９°にあれば最適の許容範囲が得られることとなり、従来の圧力角（例えば２５．１〜２５．３°）を有するものに比べてベルトの速度むらの低減に極めて有効である。
【００１９】
ここで、上記ベルト歯部の歯側面部は、１つの円の弧面で構成されていることが好ましいが、実質的に略円弧面で近似できる凸状の曲面であれば、楕円の一部や放物線の一部等、他の曲線からなる曲面であってもよい。いずれにしても略円弧面で近似できる凸状の曲面であり、０．３Ｗ圧力角が２６〜３９°であれば、本発明の効果が発揮される。
【００２０】
また、ベルト歯部において、両歯側面部同士を連結する歯先部は、先端に略平面からなる平面部を有し、かつこの平面部が歯側面部の円弧面に対し円弧面部で連続的に接続されるように形成するのが一般的な構成（図１参照）であるが、この構成に限らず、歯先部を両歯側面部の円弧面の歯先方向への延長線よりも歯元側（内側）に位置するように設けさえすれば、上記本発明の効果を発揮できる。
【００２１】
請求項２の発明では、上記請求項１の歯付ベルトにおけるベルト歯部の側面部の基準位置での圧力角（０．３Ｗ圧力角）を２８〜３５°とし、請求項３の発明では、同圧力角を２９〜３３°とする。こうすると、ベルトの速度むらをさらに低減できて好ましい。
【００２２】
請求項４の発明では、上記ベルト歯部の歯側面に位置する歯側面部の円弧半径ＲＢは、ランドライン上での歯元幅Ｗに対し、ＲＢ＝０．７Ｗ〜１．５Ｗとする。すなわち、上記のように、０．３Ｗ圧力角を大きくすることによって、ベルト歯部のプーリ歯溝部への噛込み時にベルト歯部のプーリ歯溝部への接触が遅くなり、これにより速度むらを小さくすることができるが、同じ０．３Ｗ圧力角を有する歯形であっても、その歯形の歯側面部の円弧半径によってベルト歯部のプーリ歯溝部への滑込み易さが異なるため、速度むらに影響する。つまり、ベルトのプーリへの噛込みにおいて、ベルトのランド部がプーリ歯頂部に巻き付くときには、ベルトはプーリに円弧状に巻き付くが、ランド部が巻き付いた後にベルト歯部がプーリ歯溝部へ噛み込むときには、ベルト歯部は歯の走行方向前側の歯元付近におけるピッチライン上の点を支点（回転中心）として、プーリ歯溝部に噛み込む。このとき、歯側面部の円弧半径ＲＢが大き過ぎる場合、ベルト歯部の歯先付近がプーリ歯溝側面に干渉しながら（図６（ｂ）参照）、また歯側面部の円弧半径ＲＢが小さ過ぎる場合は、ベルト歯部側面がプーリ歯頂円弧付近に干渉しながら（図６（ｃ）参照）それぞれ滑り込む。こうしてベルト歯部の歯先付近又は側面が干渉しながら滑り込むことによって、噛込み時に発生するプーリからの反力が大きくなり、ピッチラインが押し上げられて速度むらが大きくなる。
【００２３】
これに対し、ベルト歯部の歯側面部の円弧半径ＲＢがベルト歯元幅Ｗと略等しくてＲ＝０．７Ｗ〜１．５Ｗの範囲にあれば、上記の如き干渉は殆ど発生せず（図６（ａ）参照）、滑らかに滑り込むことができるため、速度むらが小さくなる。つまり、半径ＲＢが歯元幅Ｗに対し、ＲＢ＝０．７Ｗ〜１．５Ｗの範囲であれば、滑らかに滑り込むことができ、速度むらの低減に有効である。
【００２４】
請求項５の発明では、上記ベルト歯部の歯側面部の円弧半径ＲＢはＲＢ＝０．８Ｗ〜１．３Ｗとし、請求項６の発明では、ベルト歯部の歯側面部の円弧半径ＲＢはＲＢ＝０．９Ｗ〜１．１Ｗとする。こうすると速度むらをさらに低減できて好ましい。
【００２５】
請求項７の発明では、上記歯付ベルトにおけるベルト歯部の歯ピッチＰＢは、上記歯元幅Ｗに対し、ＰＢ＝１．２５Ｗ〜１．５Ｗとしている。すなわち、従来のＳＴＰＤ歯形やＨＴＤ−II歯形を有する歯付ベルトでは、高負荷伝動時のベルトランド部の摩耗を考慮して、ＰＢ＝１．５６Ｗ〜１．６４Ｗとされていた。この理由は、ベルト歯ピッチＰＢをこれよりも小さくすると、ベルトランド部の面積が小さくなり過ぎて高負荷伝動時の面圧が上がり、ランド部が摩耗してベルトが早期破損に至る危険性があるためであるが、歯ピッチ１．５〜３ｍｍの軽負荷用途のものについても、単に相似設計としているので、上記のとおりＰＢ＝１．５６Ｗ〜１．６４Ｗとされている。
【００２６】
これに対し、速度むらを低減させるためには、ベルト歯ピッチはできるだけ小さい方が有利である。例えば、ベルトにキャリッジを取り付け、往復運動をさせるプリンタの場合、ＰＢ＝１．６Ｗの歯付ベルトで歯数１４の駆動プーリを駆動させる駆動装置について、その歯付ベルトをＰＢ＝１．４Ｗのものに置き換えた場合、キャリッジ速度及びプーリ径を合わせるのに、歯数１６の駆動プーリを使用することができる。
【００２７】
そして、プーリ歯数が多い方が多角形効果が小さい（より一層円に近くなる）ので、歯ピッチが小さい方が有利である。ＰＢ＝１．５Ｗ以下であれば、従来のものに比べて上記の効果があり、速度むらが小さくなる。但し、たとえ軽負荷用途とはいえ、ＰＢ＝１．２５Ｗ未満では、プーリ歯頂部が狭くなり過ぎ、プーリの強度や加工性に問題がある。このため、ＰＢ＝１．２５Ｗ〜１．５Ｗが実用的に有効な範囲である。
【００２８】
請求項８の発明では、上記歯付ベルトのベルト歯部の歯ピッチＰＢをＰＢ＝１．３７Ｗ〜１．４７Ｗとする。この範囲が速度むらの低減とプーリの強度や加工性とから見て、さらに適切なベルトピッチの範囲となる。
【００２９】
請求項９の発明では、上記ベルト歯部の歯先部は、両歯側面部の円弧面と連続しかつ歯幅方向中心線上に中心点を持つ１つの円弧面で構成されていることを特徴とする。
【００３０】
上記のとおり、歯先部の構成は、両歯側面部の円弧面の歯先方向への延長線上内側に位置するように設けさえすればよいが、歯先部を１つの円弧面で構成すれば、平面部を有するもの（図９仮想線参照）に比べ、ベルト歯部のプーリ歯溝部への接触をさらに遅くすることができ（図９実線参照）、ベルトの速度むらをより一層低減できる利点がある。
【００３１】
請求項１０の発明では、ベルト歯部の歯先部は、両側面部の円弧面に連続するように設けられた略円弧面からなる円弧面部と、両円弧面部を接続するように設けられた略平面からなる１つの平面部とで構成されている。すなわち、プリンタの用途では、従動プーリ（図３のプーリ２参照）を平プーリとして使用することがあり、その場合、ベルト歯部の歯先部が平プーリ外径部と直接接触して走行するので、このベルト歯先部が略平面であれば広い面積で荷重を受け持つこととなり、ピッチラインの位置を安定させることができ、これによりベルトの速度むらを抑えることができる。
【００３２】
請求項１１〜１３の発明は、歯付ベルトと歯付プーリとを組み合わせた歯付ベルト伝動装置に関する発明である。請求項１１の発明では、上記請求項１〜１０のいずれか１つの歯付ベルトと、複数のプーリ歯溝部を備えた歯付プーリとを組み合わせてなる歯付ベルト伝動装置として、上記各プーリ歯溝部は、歯溝幅方向中心線に対し対称に配置された略円弧面からなる歯頂円弧部と、この歯頂円弧部に連続して歯溝幅方向中心線に対し対称に設けられた凹形状の略円弧面からなる歯溝側面部と、この両歯溝側面部同士を接続するように設けられた歯溝底部とで構成されている。そして、上記歯溝側面部は、上記ベルト歯部の歯側面部と略相似形であり、ベルトにプーリが巻き付いてベルトに張力が付与された伝動状態において、ベルト歯部の歯側面部と歯高さ方向の各位置での圧力角が略等しく構成されている。
【００３３】
上記のように、凸状円弧の歯側面部を有する歯付ベルトで、圧力角を適正範囲に大きく構成すれば、プーリ歯溝部との接触を遅くすることができるため、ベルトそのものとして速度むらを低減させる効果を有するが、プーリ歯溝形状との組合せにより、より一層大きな効果を発揮できる。すなわち、ベルト歯形状とプーリ歯溝形状の組合せにより速度むらの低減を狙った従来技術として、上記した特開昭６４―７４３４１号公報のものがある。このものは、前述のようにベルト歯部とプーリ歯溝部との間のバックラッシュが歯先部から歯先側に向かって漸増させる（つまりベルト歯側面の圧力角よりも、プーリ歯溝側面の圧力角を小さくしたもの）ことにより、噛込み時のベルト歯のプーリ歯溝への干渉を抑えることを狙ったものである（図２１参照）。
【００３４】
しかし、この構成では、確かに無負荷の伝動状態で干渉は殆ど起こらないが、現実には前述のように通常の伝動状態で、与えられる負荷トルクの影響により、ベルト歯部はプーリ歯溝部の位置に対し若干遅れた位置で噛み込むので、ベルト歯部の走行方向後側の歯部側面がプーリ歯溝部の側面に接触し、その後に滑り込む。このとき、従来例のように、ベルト歯側面の圧力角よりも、プーリ歯溝側面の圧力角を小さくすると、ベルト歯部側面はプーリ歯溝部の歯頂円弧部に接触し、ベルト歯部はプーリ歯溝部の歯頂円弧部に突き上げられながら噛み込む（図５（ｂ）参照）。これにより、プーリ歯溝部にスムーズに滑り込むことができず、ベルトピッチラインが押し上げられて速度むらが増大してしまう。実際、有限要素法を用いた速度むら解析において、ベルトとプーリの圧力角が同じものに対して、速度むらが悪化する結果となる。
【００３５】
これに対し、請求項１１の発明の構成によれば、ベルト歯部の側面とプーリ歯溝部の歯溝側面との歯高さ方向の各位置での圧力角が略等しいため、噛込み時にベルト歯部側面がプーリ歯溝部側面に対し、均一に接触してベルト歯部がプーリ歯溝部にスムーズに滑り込むため、ベルトピッチラインが押し上げられない（図５（ａ）参照）。従って、ベルト歯部側面の圧力角が従来よりも大きくベルト歯側面がプーリ歯溝側面との接触が遅いことと相俟って、ベルトの速度むらを極めて小さく抑えることができる。
【００３６】
請求項１２の発明では、請求項１０の歯付ベルトと、複数のプーリ歯溝部を備えた歯付プーリとを組み合わせてなる歯付ベルト伝動装置として、上記各プーリ歯溝部は、歯溝幅方向中心線に対し対称に配置された略円弧面からなる歯頂円弧部と、この歯頂円弧部に連続して歯溝幅方向中心線に対し対称に設けられた凹形状の略円弧面からなる歯溝側面部と、この両歯溝側面部同士を接続するように設けられた略円弧面からなる円弧面部、及び該両円弧面部同士を接続するように設けられた略平面からなる１つの平面部からなる歯溝底部とで構成されている。そして、上記歯溝側面部は、上記ベルト歯部の歯側面部と略相似形であり、ベルトにプーリが巻き付いてベルトに張力が付与された伝動状態において、ベルト歯部の歯側面部と歯高さ方向の各位置での圧力角が略等しく構成され、かつベルト歯先部とプーリ歯溝底部とが接触していることを特徴としている。
【００３７】
このようにベルト歯部の歯先部が略平面に設けられた歯付ベルトと、プーリ歯溝部の歯溝底部が略平面に設けられた歯付プーリとを組み合わせ、かつ両者の平面部が接触するように組み合わせることにより、ベルトがプーリに噛み込んで完全に噛み合った状態において、ベルト歯部の歯先部の平面部全体をプーリ歯溝部の歯溝底部の平面部により広い面積で受けることができ、このため、完全噛合い時のベルト心線位置（ピッチライン）をより安定させて、ベルトの速度むらをさらに低減することができる。
【００３８】
請求項１３の発明では、上記請求項９の歯付ベルトと、複数のプーリ歯溝部を備えた歯付プーリとを組み合わせてなる歯付ベルト伝動装置として、上記各プーリ歯溝部は、歯溝幅方向中心線に対し対称に配置された略円弧面からなる歯頂円弧部と、この歯頂円弧部に連続して歯溝幅方向中心線に対し対称に設けられた凹形状の略円弧面からなる歯溝側面部と、この両歯溝側面部同士を連続するように設けられ、上記プーリ歯幅方向中心線上に中心を持ちかつベルト歯先部の円弧半径よりも大きい半径を有する１つの円弧面からなる歯溝底部で構成されている。そして、上記歯溝側面部は、上記ベルト歯部の歯側面部と略相似形であり、ベルトにプーリが巻き付いてベルトに張力が付与された伝動状態において、ベルト歯部の歯側面部と歯高さ方向の各位置での圧力角が略等しく構成され、かつベルト歯先部とプーリ歯溝底部が接触している。
【００３９】
このように、プーリ歯溝部の歯溝底部がベルト歯部の歯先部の円弧半径よりも大きい半径の円弧面で構成されているので、この場合もやはり、ベルト歯先部円弧面の略全体をプーリ歯溝底部の円弧面の広い面積で受けることができ、上記と同様の効果が得られる。
【００４０】
さらに、この発明では、ベルトのプーリへの噛込み時、ベルト歯部の側面がプーリ歯溝部の側面を滑らかに滑り込む上に、ベルト歯部の歯先部が歯側面部と、またプーリ歯溝部の歯溝底部が歯溝側面部とそれぞれ連続的に設けられた円弧面からなっているために、ベルトとプーリとが完全噛合い状態に至る瞬間まで、ベルト歯部の側面のみならず歯先部までもがプーリ歯溝底部に滑らかに滑り込むようになり、これにより、ピッチラインの上下量が殆ど起こらず、速度むらを極めて小さくすることができる。
【００４１】
請求項１４の発明では、事務用機器として、上記歯付ベルト伝動装置が装備されていて、その歯付ベルトにキャリッジが取り付けられているものとする。このことで、歯付ベルト伝動装置の作動時に、キャリッジを移動させて印字等をするとき、ベルトの速度むらによるキャリッジの速度変動が小さくなるので、キャリッジによる印字精度や画像品質を高めることができる。
【００４２】
【発明の実施の形態】
（実施形態１）
図３は本発明の実施形態１に係る歯付ベルト伝動装置Ａの全体構成を示し、この伝動装置Ａは、プリンタや複写機に代表される事務用機器に装備されるものである。図３において、１は歯付プーリからなる駆動プーリ、２は同様の従動プーリで、これらプーリ１，２は例えば水平方向に対向して配置されている。両プーリ１，２間には歯付ベルト１０が噛合い状態で巻き掛けられ、この歯付ベルト１０の下側スパンにはインクやハンマ等の印字機構（図示せず）を装着したキャリッジ２４が取付部２４ａにて移動一体に取付固定されており、駆動プーリ１，２を正転又は逆転させて歯付ベルト１０を走行移動させることにより、キャリッジ２４をプーリ１，２間で往復動作させるようにしている。
【００４３】
図２に拡大して示すように、上記歯付プーリからなる駆動又は従動プーリ１，２は、外周のプーリ外径ライン上に一定ピッチで設けられた複数のプーリ歯溝部３，３，…（１つのみ図示する）を備えている。この各プーリ歯溝部３は、その歯溝幅方向中心線Ｃ１に対し対称に配置された円弧半径ｒ１Ｐの円弧面からなる１対の歯頂円弧部４，４と、これら両歯頂円弧部４，４に連続して上記歯溝幅方向中心線Ｃ１に対し対称に設けられ、ピッチ円ＰＣの近傍（後述の如くプーリ１，２に噛み合うベルト１０の歯部１３における歯側面部１５の円弧面中心点Ｏ１Ｂと同じ位置）に中心点Ｏ１Ｐを有しかつ後述するベルト歯部１３の歯側面部１５の円弧半径ＲＢよりも若干大きい円弧半径ＲＰ（＞ＲＢ）の凹形状の円弧面からなる１対の歯溝側面部５，５と、これら両歯溝側面部５，５を連続するように設けられた歯溝底部６とで構成され、この歯溝底部６は、両歯溝側面部５，５同士を接続するように設けられた略円弧面からなる円弧面部７，７と、該両円弧面部７，７同士を接続するように設けられた略平面からなる１つの平面部８とからなっている（尚、図２においては、理解を容易にするためにプーリ１，２の外周をベルト１０と共に展開した状態で示している）。
【００４４】
一方、上記歯付ベルト１０は、図１に拡大して示すように、弾性材からなるベルト本体１１を備えている。このベルト本体１１はゴム製又はポリウレタン製であるのが好ましく、その他、例えば合成樹脂系等の材料でもよい。ゴム製の場合、クロロプレンゴムが用いられる他、ＮＢＲ、ＳＢＲ、ＥＰＤＭ等でもよく、そのゴムの硬度はＪＩＳ−Ａで６５〜８５°程度のものがよい。ベルト本体１１をポリウレタン製とする場合、そのポリウレタンは熱硬化性でかつエーテル系のものが用いられるが、熱可塑性やエステル系のものでもよい。
【００４５】
また、上記ベルト本体１１のピッチラインＰＬ上に抗張体としての心線（図示せず）が埋設されている。この心線は、ベルト本体１１がゴム製又はポリウレタン製のいずれであっても、主としてガラス繊維、アラミド繊維が用いられ、カーボンやＰＢＯ等の繊維でもよい。また、事務用機器の消費電力を低減するために、ロストルクが小さくなるように細径の心線が望ましい。
【００４６】
また、ベルト１０の速度むらを低減する狙いからみて、ベルト１０のピッチラインＰＬを安定して維持するために、ベルト１０の曲げ剛性を低くする点、また、負荷がかけられたときの歯ピッチＰＢの維持により噛合干渉を低減し、事務用機器の起動時の速度変動を素早く減衰させるために、ベルト１０の引張弾性率を高くする点を考慮すると、高弾性率の心線を用いるのがよい。
【００４７】
上記ベルト本体１１のランドラインＬＬ上には、歯元幅Ｗ（ベルト歯部１３の後述する両方の歯側面部１５，１５の歯元方向の円弧延長線とランドラインＬＬとの交差位置間の寸法）を有する複数の歯部１３，１３，…（１つのみ図示する）がベルト長さ方向に一定の歯ピッチＰＢで形成され、この歯部１３，１３間にあるベルト本体１１の底面に、ランドラインＬＬ上に位置するランド部１２が設けられている。上記ベルト歯部１３のピッチＰＢは、上記歯元幅Ｗに対し、ＰＢ＝１．２５Ｗ〜１．５Ｗとされ、特に、ＰＢ＝１．３７Ｗ〜１．４７Ｗとするのが好ましい。
【００４８】
上記の如くベルト本体１１がゴム製である場合、その歯部１３の表面に合成繊維製の織布（図示せず）が貼り付けられる。その織布はポリアミド繊維が望ましいが、ポリエステル繊維でもよい。織布は通常、ＲＦ処理、エポキシ処理、ＲＦＬ処理等の接着処理が施され、糊ゴムにより処理される。この糊ゴム処理は、織布の表裏両面に行われることもあるが、特に事務用機器の用途ではベルト１０表面からのゴム粉の飛散を嫌い、しかもベルト１０の速度むらの低減という目的からみてベルト１０表面の摩擦係数を低くしておく必要があるために、歯部１３の表面となる側にゴム処理を行わないのが好ましい。
【００４９】
一方、ベルト本体１１がポリウレタン製である場合、歯部１３の表面に織布は設けられておらず、ベルト本体１１に心線のみが埋め込まれたものとなる。
【００５０】
本発明の特徴は、上記各ベルト歯部１３及びプーリ歯溝部３の形状にある。すなわち、図１に示すように、各ベルト歯部１３は、そのベルト長さ方向両側に、ベルト歯部１３の歯幅方向中心線Ｃ２（ベルト長さ方向の中心線）に対し対称に位置しかつランド部１２に連続する所定半径ｒ１Ｂの円弧面からなる１対の歯元部１４，１４と、これらの歯元部１４，１４に連続して歯部１３の側面に位置しかつ上記歯幅方向中心線Ｃ２に対し対称に設けられ、円弧半径ＲＢの凸形状の円弧面からなる１対の歯側面部１５，１５と、これら両歯側面部１５，１５の円弧面の円弧状の歯先側延長線１５ａよりも歯元側（内側）に位置し、両歯側面部１５，１５同士を連続するように設けられた歯先部１６とで構成され、この歯先部１６は、両歯側面部１５，１５に連続してかつ上記歯幅方向中心線Ｃ２に対し対称に設けられた所定半径ｒ２Ｂの略円弧面からなる円弧面部１７，１７と、これら両円弧面部１７，１７同士を連続するように設けられた１つの略平面からなる平面部１８とで構成されている。
【００５１】
上記各歯側面部１５の円弧面の中心点Ｏ１Ｂは、上記ベルト１０のピッチラインＰＬ上又はその近傍に位置するのが望ましい。また、この各歯側面部１５の円弧面の円弧半径ＲＢは、ＲＢ＝０．７Ｗ〜１．５Ｗに設定するのがよく、特に、ＲＢ＝０．８Ｗ〜１．３Ｗ、さらにはＲＢ＝０．９Ｗ〜１．１Ｗとする好ましい。
【００５２】
そして、上記歯付ベルト１０のベルト歯部１３側面の歯側面部１５においてランドラインＬＬから歯高さ方向に０．３Ｗ離れた基準位置Ｄでの０．３Ｗ圧力角θＢはθＢ＝２６〜３９°とされ、望ましくはθＢ＝２８〜３５°であり、そのうちθＢ＝２９〜３３°が好ましく、最適値はθＢ＝３１°（図示例のもの）である。
【００５３】
また、図２に示す如く、上記ベルト歯部１３の側面（歯幅方向の側面）とプーリ歯溝部３の側面（歯溝幅方向の側面）とは互いに略相似形であり、ベルト１０が各プーリ１，２に巻き付いてベルト１０に張力が付与された実際の伝動状態で、ベルト歯部１３及びプーリ歯溝部３の各側面の歯高さ方向の各位置でのベルト歯部１３側面の圧力角とプーリ歯溝部３側面の圧力角とが略等しく構成され、かつベルト歯部１３の歯先部１６とプーリ歯溝部３の歯溝底部６とが接触している。
【００５４】
この実施形態においては、図４に示すように、歯付ベルト１０の各歯部１３が歯付プーリからなる駆動プーリ１の各歯溝部３に噛み込むとき、与えられる負荷トルクの影響によりベルト歯部１３はプーリ歯溝部３の位置に対し若干遅れた位置で噛み込むので、ベルト歯部１３の走行方向後側の歯部１３側面がプーリ歯溝部３の側面に接触した後にベルト歯部１３がプーリ歯溝部３に滑り込む。
【００５５】
そのとき、ベルト１０のスパン（プーリ１に巻き付いていない部分）でベルトピッチラインＰＬがベルトスパンと直交する方向に上下動することにより、噛合い速度むらが発生し、上記ピッチラインＰＬの上下動量は、ベルト歯部１３がプーリ歯溝部３に滑り込む際に発生する反力と、その反力によってベルト１０が上側に押し上げられたときに発生するベルト張力の分力とによって決まるため、接触位置がベルト歯部１３とプーリ歯溝部３との完全噛合位置から離れるほどベルト張力の分力が小さくなってピッチラインＰＬの押上げ量が大きくなり、ベルト歯部１３のプーリ歯溝部３への接触が早期であると速度むらが大きくなる。
【００５６】
したがって、従来の歯付ベルト１０では、図４（ｂ）に示すように、上記したベルト歯部１３側面の０．３Ｗ圧力角θＢが小さい（θＢ＝２０．８〜２５．３°）ので、ベルト歯部１３の側面がプーリ歯溝部３の側面に早く接触するのに対し、この実施形態では、図４（ａ）に示す如く、上記０．３Ｗ圧力角θＢがθＢ≧２６°と従来よりも大きいので、ベルト歯部１３のプーリ歯溝部３側面との接触は遅くなり、このことによってベルト１０の速度むらを低減することができる。
【００５７】
一方、このように、ベルト歯部１３の側面はプーリ歯溝部３の側面と接触した後に滑り込む反力とベルト張力の分力とによってベルトスパンの移動量が決まり、そのときに、０．３Ｗ圧力角θＢが大き過ぎると、ベルト歯部１３がプーリ歯溝部３に滑り込む際に発生する反力の垂直方向（ベルトスパンと直交する方向）の成分が大きくなり過ぎ、容易に滑り込めなくなってベルトピッチラインＰＬが押し上げられ、却ってベルト１０の速度むらが増大するが、この実施形態では、上記０．３Ｗ圧力角θＢはθＢ≦３９°であるので、ベルト歯部１３がプーリ歯溝部３にスムーズに滑り込むようになり、ベルト１０の速度むらの増大を抑えることができる。つまり、０．３Ｗ圧力角θＢの最適範囲をθＢ＝２６〜３９°とすることで、ベルト１０の速度むらを可及的に低減することができる。
【００５８】
また、この実施形態では、ベルト歯部１３の側面とプーリ歯溝部３の側面との歯高さ方向の各位置での圧力角が略等しいため、図５（ａ）に示すように、ベルト歯部１３の側面がプーリ歯溝部３の側面に対し均一に接触してベルト歯部１３がプーリ歯溝部３にスムーズに滑り込むこととなる。このため、図５（ｂ）に示す如く、プーリ歯溝部３の圧力角をベルト歯部１３の圧力角よりも小さくした場合のように、ベルト歯部１３の側面がプーリ歯溝部３の側面でなくて歯頂円弧部４に接触してベルト歯部１３がプーリ歯溝部３の歯頂円弧部４に突き上げられることはなく、ベルト１０の速度むらをさらに抑制することができる。
【００５９】
また、上記ベルト歯部１３の歯側面に位置する歯側面部１５の円弧半径ＲＢは、ランドラインＬＬ上での歯元幅Ｗに対し、ＲＢ＝０．７Ｗ〜１．５Ｗとされているので、次の作用効果が得られる。すなわち、上記のように、０．３Ｗ圧力角θＢを大きくすることによって、ベルト歯部１３のプーリ歯溝部３への噛込み時にベルト歯部１３のプーリ歯溝部３への接触が遅くなり、これにより速度むらを小さくすることができるが、同じ０．３Ｗ圧力角θＢを有する歯形であっても、その歯形の歯側面部１５の円弧半径ＲＢによってベルト歯部１３のプーリ歯溝部３への滑込み易さが異なるため、速度むらに影響する。つまり、ベルト１０のプーリ１，２への噛込みにおいて、ベルト１０のランド部１２がプーリ１，２の歯頂部に巻き付くときには、ベルト１０はプーリ１，２に円弧状に巻き付くが、ランド部１２が巻き付いた後にベルト歯部１３がプーリ歯溝部３へ噛み込むときには、ベルト歯部１３は歯の走行方向前側の歯元付近におけるピッチラインＰＬ上の点を支点（回転中心）として、プーリ歯溝部３に噛み込む。このとき、歯側面部１５の円弧半径ＲＢが大き過ぎると（例えばＲＢ＝１．６Ｗ）、図６（ｂ）に示すように、ベルト歯部１３の歯先部１６付近がプーリ歯溝部３の側面に干渉しながら滑り込む一方、逆に歯側面部１５の円弧半径ＲＢが小さ過ぎる場合（例えばＲＢ＝０．６５Ｗ）は、図６（ｃ）に示す如く、ベルト歯部１３の側面がプーリ歯溝部３の歯頂円弧部４付近に干渉しながら滑り込むこととなり、こうしてベルト歯部１３の歯先部１６付近又は側面が干渉しながら滑り込むことによって、噛込み時に発生するプーリ１，２からの反力が大きくなり、ピッチラインＰＬが押し上げられて速度むらが大きくなる。
【００６０】
しかし、この実施形態のように、ベルト歯部１３の歯側面部１５の円弧半径ＲＢがベルト歯元幅Ｗと略等しければ（ＲＢ＝０．７Ｗ〜１．５Ｗ）、図６（ａ）に例示するように、上記の如き干渉は殆ど発生せず、滑らかに滑り込むことができて速度むらが小さくなる。よって、歯側面部１５の円弧半径ＲＢが歯元幅Ｗに対し、ＲＢ＝０．７Ｗ〜１．５Ｗの範囲であれば、ベルト１０の速度むらの低減に有効である。
【００６１】
また、歯付ベルト１０の歯ピッチＰＢは、歯元幅Ｗに対し、ＰＢ＝１．２５Ｗ〜１．５Ｗとされているので、以下の作用効果を奏する。すなわち、ベルト１０の速度むらを低減させるためには、ベルト１０の歯ピッチＰＢができるだけ小さくてプーリ歯数が多い方が、多角形効果が小さく（より一層円に近く）なるので、有利であり、ＰＢ＝１．５Ｗ以下であれば、従来のものに比べて、速度むらが小さくなる。一方、ＰＢ＝１．２５Ｗ未満では、プーリ歯頂部が狭くなり過ぎ、プーリ１，２の強度や加工性に問題がある。このため、この実施形態のように、ＰＢ＝１．２５Ｗ〜１．５Ｗとすることで、プーリ１，２の強度や加工性の問題を招くことなく、ベルト１０の速度むらを低減することができる。
【００６２】
さらにまた、ベルト歯部１３の歯先部１６に略平面の平面部１８が設けられている一方、プーリ歯溝部３の歯溝底部６に略平面の平面部８が設けられているので、ベルト１０がプーリ１，２に完全に噛み合った状態では、ベルト歯部１３の歯先部１６における平面部１８全体をプーリ歯溝部３の歯溝底部６における平面部８が広い面積で受けることになり、完全噛合い時のベルト１０の心線位置（ピッチラインＰＬ）をより安定させて、ベルト１０の速度むらをさらに低減することができる。
【００６３】
以上のようにベルト１０の速度むらが可及的に低減されることによって、事務用機器の印字精度や画像品質の向上等を図ることができる。
【００６４】
また、上記プーリ１，２における各プーリ歯溝部３の歯溝底部６が略平面であるので、プーリ歯溝部３の歯溝底部６をベルト歯部１３の歯先部１６と同じ略平面形状とすることができる。尚、この実施形態１において、プーリ歯溝部３の歯溝底部６のみを、プーリ中心方向に中心を持つ円弧面で形成してもよい。
【００６５】
（実施形態２）
図７及び図８は本発明の実施形態２を示し（尚、以下の各実施形態では図１及び図２と同じ部分については同じ符号を付してその詳細な説明は省略する）、この実施形態では、ベルト歯部１３の形状を変えたものである。
【００６６】
すなわち、この実施形態では、図８に示すように、プーリ１，２における各プーリ歯溝部３は、歯溝幅方向中心線Ｃ１に対し対称に配置された円弧面からなる歯頂円弧部４，４と、この歯頂円弧部４，４に連続して歯溝幅方向中心線Ｃ１に対し対称に設けられた凹形状の円弧面からなる歯溝側面部５，５と、これら両歯溝側面部５，５同士を連続するように設けられた円弧面部７，７及び平面部８からなる歯溝底部６とで構成されている。
【００６７】
一方、図７及び図８に示すように、歯付ベルト１０の各ベルト歯部１３は、そのベルト長さ方向両側に、ベルト歯部１３の歯幅方向中心線Ｃ２に対し対称に位置しかつランド部１２に連続する所定半径ｒ１Ｂの円弧面からなる１対の歯元部１４，１４と、この歯元部１４，１４に連続して歯部１３側面に位置しかつ上記歯幅方向中心線Ｃ２に対し対称に設けられた円弧半径ＲＢの凸形状の円弧面からなる１対の歯側面部１５，１５と、この両歯側面部１５，１５同士を連続するように設けられ、上記ベルト歯部１３の歯幅方向中心線Ｃ２上に中心点Ｏ２Ｂを持つ円弧半径ｒＴＢの１つの円弧面からなる歯先部１６とで構成されている。
【００６８】
そして、上記実施形態１と同様に、上記各ベルト歯部１３側面の歯側面部１５の基準位置Ｄでの０．３Ｗ圧力角θＢはθＢ＝２６〜３９°とされ、望ましくはθＢ＝２８〜３５°で、そのうちθＢ＝２９〜３３°が好ましく、最適値はθＢ＝３１°（図示例のもの）である。
【００６９】
さらに、上記ベルト歯部１３側面とプーリ歯溝部３の側面とは略相似形で、ベルト１０がプーリ１，２に巻き付いてベルト１０に張力が付与された伝動状態では、ベルト歯部１３及びプーリ歯溝部３の各側面の歯高さ方向の各位置でのベルト歯部１３側面の圧力角とプーリ歯溝部３側面の圧力角とが略等しく構成され、かつベルト歯部１３の歯先部１６とプーリ歯溝部３の歯溝底部６とが接触している。その他の構成は実施形態１と同様である。
【００７０】
したがって、この実施形態においても、上記実施形態１と同様の作用効果が得られる。そのことに加え、各ベルト歯部１３の歯先部１６が１つの円弧面で構成されているので、図９で実線にて示すように、ベルト歯部１３のプーリ歯溝部３への接触をさらに遅くすることができ、単に０．３Ｗ圧力角θＢを大きくするのみの実施形態１の構造（図９に仮想線にて示す）に比べ、ベルト１０の速度むらをさらに有効に低減できる利点がある。
【００７１】
（実施形態３）
図１０は実施形態３を示し、この実施形態では、歯付ベルト１０における各ベルト歯部１３は、上記実施形態２と同様に、その先端部に、１つの円弧面からなる歯先部１６がベルト長さ方向両側の両歯側面部１５，１５同士を連続するように設けられている。
【００７２】
これに対し、プーリ１，２における各プーリ歯溝部３の歯溝底部６は、歯溝幅方向中心線Ｃ１上に中心点Ｏ２Ｐを持ちベルト歯部１３の歯先部１６の円弧半径ｒＴＢよりも少し大きい円弧半径ｒＴＰの１つの円弧面で構成されている。
【００７３】
この実施形態の場合、各プーリ歯溝部３の歯溝底部６が各ベルト歯部１３の歯先部１６の円弧面の半径ｒＴＢよりも少し大きい半径ｒＴＰ（＞ｒＴＢ）を持つ円弧面で形成されているので、ベルト１０のプーリ１，２への噛込み時、ベルト歯部１３の側面がプーリ歯溝部３の側面により一層滑らかに滑り込む。しかも、ベルト歯部１３の歯先部１６が歯側面部１５と連続的に設けられた円弧面であり、またプーリ歯溝部３の歯溝底部６が歯溝側面部５と連続的に設けられた円弧面であるので、ベルト１０とプーリ１，２とが完全噛合い状態に至る瞬間まで、ベルト歯部１３の側面のみならず歯先部１６までもがプーリ歯溝底部６に滑らかに滑り込むようになる。これらの作用により、ピッチラインＰＬの上下量が殆ど起こらず、ベルト１０の速度むらを極めて小さくすることができる。
【００７４】
また、プーリ歯溝部３の歯溝底部６はベルト歯部１３の歯先部１６の円弧半径ｒＴＢよりも若干大きい半径ｒＴＰの円弧面で構成されているので、この場合もやはり、ベルト歯部１３の歯先部１６円弧面の略全体をプーリ歯溝部３における歯溝底部６の円弧面の広い面積で受けることができ、完全噛合い時のベルト１０の心線位置を安定させて、ベルト１０の速度むらを低減することができる。
【００７５】
（他の実施形態）
尚、上記実施形態１においては、ベルト１０がプーリ１，２に巻き付いてベルト１０に張力が付与された伝動状態で、ベルトランド部１２がプーリ外径部に接触するようにしているが、図１１に示す如く、同じ状態でベルトランド部１２がプーリ外径部に接触しないようにしてもよい。
【００７６】
また、その場合、歯付ベルト１０のランド部１２は、円弧面でもよいが、歯幅方向中心線Ｃ２に対し対称に配置された円弧面からなる歯元部１４，１４によりベルト歯部１３側面と連続して接続された略平面で構成するのがよい。すなわち、ベルト本体１１がポリウレタン製である歯付ベルト１０において、そのベルト歯部１３の歯ピッチＰＢが１．５ｍｍ以下であるときには、心線をランド部１２から離すために設ける凹部の寸法が極めて小さく、金型の加工が難しいため、上記の如き凹部を設けずに、ランド部１２上に直接心線を配設しているが、この心線がプーリ１，２の外径部に接触して傷付けられないようにすべく、ベルト１０のランド部１２がプーリ１，２の外径部と接触しない状態で使用される。従って、上記のようにベルト１０のランド部１２を略平面とすることで、上記心線の位置を安定させることができる。
【００７７】
また、上記各実施形態は、プリンタや複写機等の事務用機器に装備された歯付ベルト１０及び伝動装置Ａについて説明しているが、本発明は、事務用機器以外の歯付ベルト及び伝動装置に対しても適用できるのはいうまでもない。
【００７８】
また、上記各実施形態では、ベルト歯部１３の両歯側面部１５，１５同士を連結する歯先部１６は、先端に略平面からなる平面部１８を有しかつこの平面部１８が各歯側面部１５の円弧面に円弧面部１７で連続的に接続されるように形成し（図１参照）、或いは両歯側面部１５，１５の円弧面と連続しかつ歯幅方向中心線Ｃ２上に中心点を持つ１つの円弧面で構成している（図７参照）が、その他の形状の歯先部を設けることができる。例えば図１２（ａ）に示す如く、平面部１８の中央に突起部２０を設けた歯先部１６や、図１２（ｂ）に示すように歯幅方向の中央に凹部２１を形成した歯先部１６等でもよく、さらにその他の公知の歯先部のいずれであっても本発明の効果が発揮される。要は、歯先部１６を両歯側面部１５，１５の円弧面の歯先方向への延長線よりも歯元側（内側）に位置するように設けさえすればよいのである。
【００７９】
【実施例】
（ＦＥＭ解析評価）
次に、具体的に実施した実施例について説明する。まず、歯付ベルトの速度むらをＦＥＭ解析法を用いて解析した。このＦＥＭ解析では、汎用ソフトウェア「ＡＢＡＱＵＳ」を用いた２次元の動的解析とした。図１３に示すように、解析モデルは駆動及び従動プーリの１，２の２つのプーリと、内側に歯部１３を有するエンドレスのベルト１０とをモデル化し、ベルト１０に張力を付与した後にプーリ１，２を回転させるものとした。ベルト歯部１３及びプーリ歯溝部３の各形状は上記実施形態と同様の形状に合わせて形成した（図１３では実施形態１の形状に合わせて形成したモデルを例示している）。ベルトの材料の各定数は、歯ピッチが２．１１７ｍｍのベルト及びその各構成材料で実測して入力した（歯形状が変わっても材料定数は変化しないものであるとした）。ベルト本体は四角形の平面要素に、また心線は梁要素にそれぞれ設定し、プーリ１，２と接触する表面は摩擦を考慮してインタフェース要素とした。プーリ表面は剛表面でモデル化した。尚、図１４はＦＥＭ解析法による解析途中で噛合状態にある解析モデルの要部を示しており、図１４（ａ）は本発明の実施例の解析モデルを、また図１４（ｂ）は従来例の解析モデルをそれぞれ示す。
【００８０】
そして、ベルトピッチライン上の１点の速度を出力して速度むらのデータを得た。そのデータを図１５に示す。図１５（ａ）は、ベルト歯部が歯先部に１つの略平面からなる平面部を備えていて、０．３Ｗ圧力角が３１°の本発明例（本発明の実施形態１に相当するもの）のデータであり、また、図１５（ｂ）は従来例（０．３Ｗ圧力角が２５．３°）のデータを示している。
【００８１】
また、このデータからベルト歯部の０．３Ｗ圧力角と速度むら（ベルト速度の変動値）との関係を求めたところ、図１６に示す結果が得られた。図１６においては、ベルト速度の変動値は上記従来例を「１．０」とする指数で表している。また、図１６中、実線はベルト歯部が、１つの略平面からなる歯先部を備えた歯部形状を持つものを示し、そのうち、０．３Ｗ圧力角が２６〜３９°のものが本発明例となる。一方、破線はベルト歯部が、両歯側面部同士を連続するように設けられかつ歯幅方向中心線上に中心点を持つ１つの円弧面からなる歯先部を備えた実施形態２に相当する本発明例を示す。
【００８２】
（台上評価）
一方、ベルト及びプーリからなる伝動装置を作製して、そのベルトの速度むらを測定装置で測定する台上試験をも行った。すなわち、本発明例として、図７に示す実施形態２の構成で圧力角が異なる（０．３Ｗ圧力角＝２９．２°，３１．１°）２つの歯付ベルトを作り（本発明例１，２）、従来例として１つの略平面を有する歯先部を備えかつ歯側面部の０．３Ｗ圧力角が２５．３°の歯付ベルトを作った。その各々の寸法は下記の表１のとおりである。尚、寸法値はベルト歯部のピッチ（２．１１７ｍｍ）を「１．０」とする指数で表している。
【００８３】
【表１】

Figure 0003838819
【００８４】
具体的には、歯付ベルトは歯ピッチ２．１１７ｍｍの円弧歯形状の歯部を持つゴム製のもので、そのゴムは硬度７０°のクロロプレンゴムで、心線は径０．３ｍｍのガラス繊維からなる。織布はポリアミドウーリー加工糸からなり、ＲＦ処理と、裏面のみのゴム糊処理とを施した。
【００８５】
そして、これらの歯付ベルトについて、実際の走行時の速度むらを図１７に示すベルト速度むら測定装置により測定した。この測定装置は、試験用の歯付ベルト１０を巻き掛ける歯付プーリからなる駆動及び従動プーリ１，２を備えており、その従動プーリ２への静荷重ＤＷによりベルト張力を付与しかつ従動プーリ２を無負荷にした状態で駆動プーリ１を図で矢印の方向に回転させ、そのときのベルト１０の緩み側スパンにおいて駆動プーリ１の軸心からｄ１＝１０ｍｍ離れた部位に対し、その部位からベルト側方にｄ２＝１００±２ｍｍ離れた位置のプローブ４３からレーザ光４３ａを当て、そのプローブ４３の出力信号に基づいて速度むら測定器４４によりベルト４０の速度むらを測定し、この速度むらの周波数をＦＦＴ４５により解析してパソコン４６に取り込み、そのデータをプリンタ４７によりプリントするようにしたものである。この速度むら測定装置の測定データを図１８に、またベルト１０の速度むらの周波数を分析したデータを図１９にそれぞれ示す（図１９（ａ）は本発明例２を、図１９（ｂ）は従来例をそれぞれ示している）。また、ベルトの速度むら測定データから得られたベルト歯部の０．３Ｗ圧力角と速度むらとの関係を図２０に示す。尚、この図２０におけるベルト速度の変動値も従来例（０．３Ｗ圧力角２５．３°）を「１．０」とする指数値である。
【００８６】
上記図１６から明らかなように、ベルト歯部側面の０．３Ｗ圧力角を２６〜３９°とすれば、従来例のように０．３Ｗ圧力角を２５．３°とするのに比べ、ベルトの速度むらが低減していることが裏付けられた。特に、０．３Ｗ圧力角を２８〜３５°とし、さらには２９〜３３°とすれば、ベルトの速度むらが大きく低減し、３１°が最適値であることが判る。
【００８７】
【発明の効果】
以上説明したように、請求項１では、軽負荷伝動用の歯付ベルトの各ベルト歯部の略円弧面からなる歯元部と、凸形状の略円弧面からなる歯側面部とをベルト歯部の歯幅方向中心線に対し対称に配置し、これら歯側面部同士を連続する歯先部を歯側面部の円弧面の歯先側延長線よりも歯元側に配置し、ランドライン上での歯元幅Ｗに対し、ベルト歯部の歯側面部においてランドラインから歯高さ方向に０．３Ｗ離れた基準位置での０．３Ｗ圧力角を２６〜３９°とし、歯側面部と略相似形でかつ張力の付与された伝動状態において、該歯側面部と歯高さ方向の各位置での圧力角が略等しい歯溝側面部を有する複数のプーリ歯溝部がプーリ外径ライン上に一定ピッチで設けられた歯付プーリに巻き付けた。また、請求項２の発明では、上記０．３Ｗ圧力角を２８〜３５°とした。さらに、請求項３の発明では、同圧力角を２９〜３３°とした。従って、これらの発明によれば、ベルト歯部のプーリ歯溝部への噛合時にベルト歯部の側面をプーリ歯溝部の側面に遅く接触させるとともに、ベルト歯部がプーリ歯溝部に滑り込む際に発生する反力の垂直方向の成分を小さくして、容易に滑り込ませることができ、よって歯付ベルトの速度むらを大幅に低減して、プリンタに代表される軽負荷伝動下で歯付ベルトを駆動させる事務用機器の印字精度や画像品質の向上等を図ることができるという実用上優れた効果が得られる。
【００８８】
請求項４の発明では、ベルト歯部の歯側面部の円弧半径を０．７Ｗ〜１．５Ｗとした。また、請求項５の発明では、上記歯側面部の円弧半径を０．８Ｗ〜１．３Ｗとした。さらに、請求項６の発明では、同円弧半径を０．９Ｗ〜１．１Ｗとした。これらの発明によれば、ベルトのプーリへの噛込み時に、ベルトのランド部がプーリ歯頂部に巻き付いた後にベルト歯部がプーリ歯溝部へ噛み込む際、ベルト歯部の歯先付近がプーリ歯溝側面に、またベルト歯部側面がプーリ歯頂円弧付近にそれぞれ干渉するのを防いで、ベルト歯部をプーリ歯溝部へ滑らかに滑り込ませることができ、ピッチラインの押上げを抑えてベルトの速度むらをさらに低減することができる。
【００８９】
請求項７の発明では、上記ベルト歯部の歯ピッチを１．２５Ｗ〜１．５Ｗとした。また、請求項８の発明では、同歯ピッチを１．３７Ｗ〜１．４７Ｗとした。これらの発明によれば、プーリ歯数を多くして多角形効果によりベルトの速度むらを低減しつつ、プーリの強度や加工性の確保を図ることができる。
【００９０】
請求項９の発明によると、ベルト歯部の歯先部を、両歯側面部の円弧面と連続しかつ歯幅方向中心線上に中心点を持つ１つの円弧面で構成したことにより、ベルト歯部のプーリ歯溝部への接触をさらに遅くして、ベルトの速度むらをより一層低減することができる。
【００９１】
請求項１０の発明によると、ベルト歯部の歯先部を、両側面部の円弧面に連続するように設けられた略円弧面からなる円弧面部と、両円弧面部を接続するように設けられた略平面からなる１つの平面部とで構成したことにより、プリンタの用途で従動プーリを平プーリとして使用し、ベルト歯部の歯先部を平プーリ外径部と直接接触して走行させる場合、略平面のベルト歯先部により広い面積で荷重を受け持たせてピッチラインの位置を安定させることができ、歯付ベルトの速度むらの低減を図ることができる。
【００９２】
請求項１１の発明によれば、請求項１〜１０の歯付ベルトと歯付プーリとを組み合わせてなる歯付ベルト伝動装置として、歯付プーリの各プーリ歯溝部の円弧面からなる歯頂円弧部と、凹形状の円弧面からなる歯溝側面部とを歯溝幅方向中心線に対し対称に配置し、両歯溝側面部同士を接続するように歯溝底部を設け、プーリ歯溝部の歯溝側面部をベルト歯部の歯側面部と略相似形とし、ベルトがプーリに巻き付いてベルトに張力が付与された状態で、ベルト歯部及びプーリ歯溝部の各側面の歯高さ方向の各位置でのベルト歯部側面の圧力角とプーリ歯溝部側面の圧力角とを略等しくしたことにより、伝動状態でのベルト歯部のプーリ歯溝部への噛込み時、にベルト歯部側面がプーリ歯溝部側面に均一に接触してベルト歯部がプーリ歯溝部にスムーズに滑り込むようになり、ベルトピッチラインの押上げを抑えて、ベルトの速度むらをさらに低減することができる。
【００９３】
請求項１２の発明によると、請求項１０の歯付ベルトと歯付プーリとを組み合わせてなる歯付ベルト伝動装置として、歯付プーリの各プーリ歯溝部の歯溝底部を、両歯溝側面部同士を接続する略円弧面からなる円弧面部と、これら両円弧面部同士を接続する略平面からなる１つの平面部とからなるものとし、プーリ歯溝部の歯溝側面部をベルト歯部の歯側面部と略相似形とし、ベルトがプーリに巻き付いてベルトに張力が付与された状態で、ベルト歯部及びプーリ歯溝部の各側面の歯高さ方向の各位置でのベルト歯部側面の圧力角とプーリ歯溝部側面の圧力角とを略等しくし、かつベルト歯先部とプーリ歯溝底部とを接触させたことにより、ベルトがプーリに完全に噛み合った状態で、ベルト歯部の歯先部の平面部全体をプーリ歯溝部の歯溝底部の平面部により広い面積で受けて、完全噛合い時のベルト心線位置を安定させてベルトの速度むらをさらに低減することができる。
【００９４】
請求項１３の発明によれば、請求項９の歯付ベルトと歯付プーリとを組み合わせてなる歯付ベルト伝動装置として、歯付プーリの各プーリ歯溝部の歯溝底部を、両歯溝側面部同士を連続するように設けられ、プーリ歯幅方向中心線上に中心を持ちかつベルト歯先部の円弧半径よりも大きい半径を有する１つの円弧面からなるものとし、プーリ歯溝部の歯溝側面部をベルト歯部の歯側面部と略相似形とし、ベルトがプーリに巻き付いてベルトに張力が付与された状態で、ベルト歯部及びプーリ歯溝部の各側面の歯高さ方向の各位置でのベルト歯部側面の圧力角とプーリ歯溝部側面の圧力角とを略等しくし、かつベルト歯先部とプーリ歯溝底部とを接触させたことにより、ベルトがプーリに完全に噛み合った状態で、ベルト歯部の歯先部全体をプーリ歯溝部により広い面積で受けるとともに、完全噛合い状態に至るまでベルト歯部の側面のみならず歯先部をもプーリ歯溝底部に滑らかに滑り込ませることができ、ベルトの速度むらのより一層の低減を図ることができる。
【００９５】
請求項１４の発明によると、上記歯付ベルト伝動装置が装備されていて、その歯付ベルトにキャリッジが取り付けられている事務用機器としたことにより、その事務用機器のキャリッジの速度変動を小さくして印字精度や画像品質を高めることができる。
【図面の簡単な説明】
【図１】 本発明の実施形態１における歯付ベルトの歯部を拡大して示す断面図である。
【図２】 実施形態１における歯付ベルト伝動装置の歯付ベルトの歯部が歯付プーリに噛み合った状態を展開して示す拡大断面図である。
【図３】 歯付ベルト伝動装置の全体構成を概略的に示す正面図である。
【図４】 歯付ベルトの歯部が歯付プーリの歯溝部に噛み合う状態を概略的に示す説明図である。
【図５】 歯付ベルトの歯部側面と歯付プーリの歯溝部側面との圧力角の相違に応じた噛合状態を示す図４相当図である。
【図６】 ベルト歯部の歯側面部の円弧半径の大きさに応じた噛合状態を示す図４相当図である。
【図７】 本発明の実施形態２における歯付ベルトの歯部を示す図１相当図である。
【図８】 実施形態２を示す図２相当図である。
【図９】 実施形態２において歯付ベルトの歯部が歯付プーリの歯溝部に噛み合う状態を概略的に示す図４相当図である。
【図１０】 実施形態３を示す図２相当図である。
【図１１】 ベルトに張力が付与された伝動状態でベルトランド部がプーリ外径部に接触しない構成の他の実施形態を示す図２相当図である。
【図１２】 ベルト歯部の歯先部の変形例を概略的に示す図である。
【図１３】 ベルトの速度むらをＦＥＭ解析法により解析するための解析モデルの全体構成を示す図である。
【図１４】 解析モデルの要部を示す図である。
【図１５】 ベルトの速度むらをＦＥＭ解析法により解析したデータを示す図である。
【図１６】 ベルトの速度むら解析データから得られたベルト歯部の圧力角と速度むらとの関係を示す図である。
【図１７】 ベルトの速度むら測定装置を示す図である。
【図１８】 ベルトの速度むら測定装置の測定データを示す図である。
【図１９】 ベルトの速度むらの周波数を分析したデータを示す図である。
【図２０】 ベルトの速度むら測定データから得られたベルト歯部の圧力角と速度むらとの関係を示す図である。
【図２１】 従来の歯付ベルトの歯部が歯付プーリに噛み合った状態を示す図２相当図である。
【符号の説明】
Ａ 歯付ベルト伝動装置
１，２ プーリ
３ プーリ歯溝部
４ 歯頂円弧部
５ 歯溝側面部
６ 歯溝底部
７ 円弧面部
８ 平面部
Ｃ１ 歯溝幅方向中心線
Ｏ２Ｐ 中心点
ｒＴＰ 円弧半径
１０ 歯付ベルト
１１ ベルト本体
１２ ランド部
１３ ベルト歯部
１４ 歯元部
１５ 歯側面部
１６ 歯先部
１７ 円弧面部
１８ 平面部
Ｄ 基準位置
ＰＬ ピッチライン
ＬＬ ランドライン
Ｃ２ 歯幅方向中心線
Ｏ２Ｂ 中心点
ｒＴＢ 円弧半径
θＢ ０．３Ｗ圧力角
Ｗ 歯元幅[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toothed belt, a toothed belt transmission device, and office equipment using the same, and particularly relates to a technical field for reducing uneven speed of the belt (speed fluctuation).
[0002]
[Prior art]
Conventionally, as this type of toothed belt, a belt having a trapezoidal shape is generally used. However, a higher load can be transmitted and noise can be further reduced. To this end, a tooth-shaped belt having a convex side surface has been proposed and is now mainstream. One of the tooth profiles is a so-called STPD tooth profile disclosed in Japanese Patent Laid-Open No. 50-42252, and the other is a so-called HTD-II tooth profile disclosed in Japanese Patent Laid-Open No. 59-89852. is there. The former STPD tooth profile is put into practical use, for example, under the trade name “Super Torque Synchro Belt” of Bando Chemical Co., Ltd., and the latter HTD-II tooth profile as the product name “Power Grip GT Belt” of Unitta Corporation. ing.
[0003]
In addition, a toothed belt disclosed in Japanese Patent Application Laid-Open No. 64-74341 has been proposed for the purpose of precise positioning driving of a movable part in office equipment. As shown in FIG. 21, a plurality of belt teeth 13 ', 13',... (Only one is shown) are provided at a constant pitch on the land line LL of the main body 11 'of the belt 10'. The belt tooth portion 13 ′ includes tooth base portions 14 ′ and 14 ′ formed of circular arc surfaces arranged symmetrically with respect to the tooth width direction center line C 2, and the tooth base portions 14 ′ and 14 ′ and the above tooth teeth. Tooth side surface portions 15 'and 15' made of convex circular arc surfaces provided symmetrically with respect to the width direction center line C2, and the tooth width direction center line C2 continuous to the tooth side surfaces 15 'and 15'. Are provided with circular arc surface portions 17 'and 17' formed symmetrically with respect to each other, and these circular arc surface portions 17 'and 17' are connected to each other by a flat surface portion 18 'consisting of one plane. In the static meshing state of the toothed belt 10 ′ with the toothed pulley 1 ′, the tooth root portion 14 ′ of each belt tooth portion 13 ′ is substantially the same as the crest arc portion 4 ′ of the pulley tooth groove portion 3 ′. Contact, the backlash at the pulley tooth groove portion 3 'of the belt tooth portion 13' gradually increases from the tooth root of the belt tooth portion 13 'to the tooth tip, and the depth of the pulley tooth groove portion 3' becomes the belt tooth portion 13 '. It is configured to be higher than the height.
[0004]
In this device, the backlash with the pulley tooth groove portion 3 'is eliminated from the tooth root portion 14' of the belt tooth portion 13 ', while the backlash with the pulley tooth groove portion 3' is removed from the tooth root of the belt tooth portion 13 '. The belt tooth portion 13 'is gradually increased toward the tip of the tooth, and the meshing interference between the belt tooth portion 13' and the apex arc portion 4 'of the pulley tooth groove portion 3' is suppressed. Variations in the belt pitch line PL due to this meshing interference are reduced. In FIG. 21, reference numeral 5 'denotes a concave tooth groove side surface portion of the pulley tooth groove portion 3', and 6 'denotes a tooth groove bottom portion. Further, the pitch line PL of the belt 10 'coincides with the pitch circle PC of the pulley 1'. In order to facilitate understanding, FIG. 21 shows the outer peripheral portion of the pulley 1 ′ along with the belt 10 ′.
[0005]
[Problems to be solved by the invention]
By the way, in office equipment represented by printers and copiers, printing devices (including image printing) using a toothed belt transmission are generally used. In this printing apparatus, a carriage equipped with a printing mechanism such as ink or hammer is attached to a toothed belt, the toothed belt is stretched between toothed pulleys, and the carriage is reciprocated by rotating the pulley forward and backward. It has become.
[0006]
In order to improve the printing accuracy and image quality by the carriage, it is required to reduce the speed unevenness (speed fluctuation) when the toothed belt travels as much as possible. In particular, in printers, color printing and its high speed and high image quality have been progressing rapidly in recent years, and the meshing vibration of the toothed belt (speed unevenness due to meshing) can cause uneven printing and uneven image. Therefore, there is a strong demand for reducing the unevenness of the meshing speed of the toothed belt.
[0007]
In office equipment such as printers, toothed belts having a tooth portion pitch of 3 mm or less (for example, 3 mm, 2 mm, 1.5 mm, etc.) in the above-mentioned STPD tooth profile or HTD-II tooth profile are generally used. As the shape of the tooth portion, a shape obtained by reducing the tooth shape of a relatively large tooth portion pitch, such as an 8 mm pitch or a 5 mm pitch, as it is is substantially similar.
[0008]
However, these tooth profiles were originally developed for the purpose of high load transmission, and therefore, no consideration has been given to the requirement to reduce the speed unevenness.
[0009]
The above-mentioned toothed belt disclosed in Japanese Patent Application Laid-Open No. 64-74341 has been proposed in consideration of the reduction of the speed unevenness to some extent, but can be an optimum tooth profile for the reduction of the speed unevenness. It was not sufficient to reduce the uneven speed as much as possible.
[0010]
In other words, as described above, the research on the tooth shape and the like for reducing the speed unevenness of the toothed belt has hardly been performed.
[0011]
In view of these points, the present invention has been made by repeatedly conducting analysis and experiments on various factors that constitute the tooth shape of the toothed belt used by the inventor as described above, The purpose is to reduce the uneven speed of the toothed belt as much as possible.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, as a factor that has not been considered at all as a result of research by the present inventors, in a toothed belt having a convex side surface of the belt tooth portion, a predetermined position on the side surface It has been found that the pressure angle at the cylinder has an extremely large influence on the speed unevenness. The pressure angle refers to the side surface of the belt tooth portion at a position separated from the land line by 0.3 W in the tooth height direction (this position is the reference position) where W is the root width on the belt land line. Hereinafter, it is also referred to as “0.3 W pressure angle”. The reason for this is that the convex tooth side surface of the belt tooth side surface usually has a tooth height of around 0.6 W, so that the “0.3 W pressure angle” at the reference position at the center of the tooth height is convex. This is because it becomes a substantially effective index as the pressure angle of the shape tooth profile.
[0013]
The conventional toothed belt having the STPD tooth profile and the HTD-II tooth profile is intended for high load transmission. Therefore, in order to avoid tooth jumping (jumping) of the belt at high load, the above-mentioned 0.3 W pressure on the side surface of the tooth portion is used. The corner is set small. For example, in the STPD tooth profile with a tooth pitch of 1.5 to 3.0 mm, the 0.3 W pressure angle is in the range of 25.1 to 25.3 °, and in the HTD-II tooth profile with a pitch of 1.5 to 3.0 mm. The 0.3 W pressure angle is set in the range of 20.8 to 21.1 °. On the other hand, since the toothed belt used for the office machine is driven under light load transmission conditions, there is almost no need to consider the tooth skipping of the belt as described above. As a result of the inventor's research, it has been found that the belt speed unevenness can be greatly reduced by setting the 0.3 W pressure angle on the side surface of the tooth portion to 26 to 39 °.
[0014]
Specifically, in the invention of claim 1, For light load transmission The toothed belt includes a belt main body in which a tensile body is embedded on a pitch line, and a plurality of belt tooth portions provided at a constant pitch on a land line of the belt main body. And each said belt tooth part is located in the tooth | gear part side which consists of the substantially circular arc surface symmetrically arrange | positioned with respect to the tooth-width direction centerline, and this tooth | gear base part, and the said tooth width direction A tooth side surface portion formed of a convex arcuate surface provided symmetrically with respect to the center line, and the tooth side surface portions located on the tooth root side of the tooth tip side extension line of the arc surface of the both tooth side surface portions, , And the tooth width on the land line is W. The tooth side surface portion of the belt tooth portion is 0. 0 in the tooth height direction from the land line. The pressure angle (0.3W pressure angle) at the reference position 3W apart is 26-39 ° A plurality of pulley teeth having a tooth gap side surface that is substantially similar to the tooth side surface and has a pressure angle at each position in the tooth height direction substantially equal to that of the tooth side surface in a transmission state in which tension is applied. The groove is wound around a toothed pulley provided at a constant pitch on the pulley outer diameter line. It is characterized by that.
[0015]
When the tooth part of the toothed belt bites into the tooth groove part of the toothed pulley on the driving side, the belt tooth part bites at a position slightly delayed from the position of the pulley tooth groove part due to the influence of the applied load torque. The side surface of the tooth portion on the rear side in the running direction of the belt tooth portion contacts the side surface of the pulley tooth groove portion, and then the belt tooth portion slides into the pulley tooth groove portion. At this time, the belt pitch line moves up and down in a direction perpendicular to the belt span in the belt span (portion not wrapped around the pulley), thereby causing uneven meshing speed. The vertical movement amount of the pitch line is determined by a reaction force generated when the belt tooth portion slides into the pulley tooth groove portion and a component force of the belt tension generated when the belt is pushed up by the reaction force. For this reason, as the contact position moves away from the complete meshing position between the belt tooth portion and the pulley tooth groove portion, the component force of the belt tension decreases, and the pitch line push-up amount increases. In other words, the speed unevenness increases as the contact of the belt tooth portion to the pulley tooth groove portion is made earlier.
[0016]
Therefore, when the 0.3 W pressure angle is small as in the conventional tooth shape, the side surface of the belt tooth portion quickly contacts the side surface of the pulley tooth groove portion (see FIG. 4 (b)). Thus, when the 0.3 W pressure angle is larger than the conventional one, the contact of the belt tooth portion with the side surface of the pulley tooth groove portion becomes slow (see FIG. 4A), thereby reducing the belt speed unevenness. Can do.
[0017]
On the other hand, the 0.3 W pressure angle cannot be increased in a dark manner. If it is too large, the speed unevenness increases. That is, as described above, the amount of movement of the belt span is determined by the reaction force that slips after the side surface of the belt tooth portion comes into contact with the side surface of the pulley tooth groove portion and the component force of the belt tension. If it is too large, the component in the vertical direction (in the direction perpendicular to the belt span) of the reaction force generated when the belt tooth slides into the pulley tooth groove will become too large, making it difficult to slip and pushing up the belt pitch line. It is.
[0018]
Therefore, according to the analysis result of the present inventor, the above-mentioned 0.3 W pressure angle is within the range of 26 to 39 ° as described above, so that an optimum allowable range can be obtained. 25.3 °), which is extremely effective in reducing the uneven speed of the belt.
[0019]
Here, it is preferable that the tooth side surface portion of the belt tooth portion is composed of an arc surface of one circle, but if it is a convex curved surface that can be approximated by a substantially arc surface, a part of the ellipse Or a curved surface made of another curve, such as a part of a parabola. In any case, if it is a convex curved surface that can be approximated by a substantially arc surface, and the 0.3 W pressure angle is 26 to 39 °, the effect of the present invention is exhibited.
[0020]
Further, in the belt tooth portion, the tooth tip portion that connects the two tooth side surface portions has a flat surface portion that is substantially flat at the tip, and this flat surface portion is continuous with the arc surface portion with respect to the arc surface of the tooth side surface portion. It is a general configuration (see FIG. 1) that is formed so as to be connected to the teeth. However, the present invention is not limited to this configuration, and the tooth tip part is more than the extension line in the tooth tip direction of the arc surface of both tooth side parts. The effect of the present invention can be exhibited as long as it is provided so as to be positioned on the tooth base side (inner side).
[0021]
In the invention of claim 2, the pressure angle (0.3 W pressure angle) at the reference position of the side surface portion of the belt tooth portion in the toothed belt of claim 1 is set to 28 to 35 °, and in the invention of claim 3, The pressure angle is 29 to 33 °. This is preferable because the uneven speed of the belt can be further reduced.
[0022]
In the invention of claim 4, the arc radius RB of the tooth side surface portion located on the tooth side surface of the belt tooth portion is set to RB = 0.7 W to 1.5 W with respect to the tooth root width W on the land line. That is, by increasing the 0.3 W pressure angle as described above, the contact of the belt tooth portion with the pulley tooth groove portion becomes slow when the belt tooth portion is engaged with the pulley tooth groove portion, thereby reducing the speed unevenness. However, even with a tooth profile having the same 0.3 W pressure angle, the ease of sliding the belt tooth portion into the pulley tooth groove portion varies depending on the arc radius of the tooth side surface portion of the tooth shape. Affect. In other words, when the belt land is wrapped around the pulley tooth crest when the belt is caught in the pulley, the belt is wound around the pulley in an arc shape, but after the land is wound, the belt tooth is bitten into the pulley tooth groove. When the belt tooth portion is engaged, the belt tooth portion is engaged with the pulley tooth groove portion with a point on the pitch line in the vicinity of the tooth root on the front side of the tooth traveling direction as a fulcrum (rotation center). At this time, when the arc radius RB of the tooth side surface portion is too large, the vicinity of the tooth tip of the belt tooth portion interferes with the pulley tooth groove side surface (see FIG. 6B), and the arc radius RB of the tooth side surface portion is small. If too much passes, the belt tooth side faces slip into each other while interfering with the vicinity of the pulley crest arc (see FIG. 6C). In this way, when the vicinity of the tooth tip or the side surface of the belt tooth part slides while interfering, the reaction force generated from the pulley during the engagement becomes large, the pitch line is pushed up, and the speed unevenness increases.
[0023]
On the other hand, if the arc radius RB of the tooth side surface portion of the belt tooth portion is substantially equal to the belt tooth root width W and is in the range of R = 0.7 W to 1.5 W, the above interference hardly occurs ( (See FIG. 6 (a)), since it can slide smoothly, the speed unevenness is reduced. In other words, if the radius RB is within the range of RB = 0.7 W to 1.5 W with respect to the tooth root width W, it is possible to slip smoothly and is effective in reducing the speed unevenness.
[0024]
In the invention of claim 5, the arc radius RB of the tooth side surface portion of the belt tooth portion is RB = 0.8 W to 1.3 W, and in the invention of claim 6, the arc radius RB of the tooth side surface portion of the belt tooth portion is RB = 0.9W to 1.1W. This is preferable because the speed unevenness can be further reduced.
[0025]
In the invention of claim 7, the tooth pitch PB of the belt tooth portion in the toothed belt is set to PB = 1.25 W to 1.5 W with respect to the tooth width W. That is, in the conventional toothed belt having the STPD tooth profile and the HTD-II tooth profile, PB = 1.56 W to 1.64 W is set in consideration of wear of the belt land portion during high load transmission. The reason for this is that if the belt tooth pitch PB is made smaller than this, the area of the belt land portion becomes too small, the surface pressure at the time of high load transmission increases, the land portion wears, and the belt may be damaged early. This is because, for light load applications with a tooth pitch of 1.5 to 3 mm, the design is simply similar, so that PB = 1.56 W to 1.64 W as described above.
[0026]
On the other hand, in order to reduce the speed unevenness, it is advantageous that the belt tooth pitch is as small as possible. For example, in the case of a printer that attaches a carriage to a belt and makes a reciprocating motion, for a driving device that drives a driving pulley with 14 teeth with a toothed belt with PB = 1.6 W, the toothed belt is with PB = 1.4 W. If replaced with one, a drive pulley with 16 teeth can be used to match the carriage speed and pulley diameter.
[0027]
Since the polygonal effect is smaller (more closer to a circle) when the number of pulley teeth is larger, it is advantageous that the tooth pitch is smaller. If PB = 1.5 W or less, the above effect is obtained compared to the conventional one, and the speed unevenness is reduced. However, even if it is a light load application, if it is less than PB = 1.25 W, the pulley tooth crest becomes too narrow, and there is a problem in the strength and workability of the pulley. For this reason, PB = 1.25W-1.5W is a practically effective range.
[0028]
In the invention of claim 8, the tooth pitch PB of the belt tooth portion of the toothed belt is set to PB = 1.37W to 1.47W. This range is a more appropriate belt pitch range in view of reduction in speed unevenness and pulley strength and workability.
[0029]
According to a ninth aspect of the present invention, the tooth tip portion of the belt tooth portion is constituted by one circular arc surface that is continuous with the circular arc surfaces of both tooth side surface portions and has a center point on the center line in the tooth width direction. And
[0030]
As described above, the tooth tip portion only needs to be provided so as to be positioned on the inner side of the extension line in the tooth tip direction of the arc surface of both tooth side surface portions, but the tooth tip portion is constituted by one arc surface. For example, the contact of the belt tooth portion with the pulley tooth groove portion can be further slowed (see the solid line in FIG. 9) and the belt speed unevenness can be further reduced as compared with the one having a flat portion (see the phantom line in FIG. 9). There are advantages.
[0031]
In the invention of claim 10, the tooth tip portion of the belt tooth portion is an arc surface portion formed of an approximately arc surface provided so as to be continuous with the arc surfaces of the both side surface portions, and an approximate shape provided so as to connect both arc surface portions. It is composed of a single flat surface portion. That is, in a printer application, a driven pulley (see pulley 2 in FIG. 3) may be used as a flat pulley, and in this case, the tooth tip portion of the belt tooth portion travels in direct contact with the outer diameter portion of the flat pulley. Therefore, if the belt tooth tip portion is substantially flat, the load is handled in a wide area, and the position of the pitch line can be stabilized, thereby suppressing unevenness of the belt speed.
[0032]
The inventions of claims 11 to 13 are inventions related to a toothed belt transmission device in which a toothed belt and a toothed pulley are combined. In the invention of claim 11, the toothed belt according to any one of claims 1 to 10 above. And double As a toothed belt transmission device in combination with a toothed pulley having a plurality of pulley tooth groove portions, each pulley tooth groove portion is a tooth crest composed of a substantially arcuate surface arranged symmetrically with respect to the center line in the tooth groove width direction. Connect the arcuate part, the tooth gap side part composed of a substantially arcuate concave surface provided symmetrically with respect to the center line in the tooth gap width direction, and the tooth gap side parts. It is comprised with the tooth gap bottom part provided in this way. And above The tooth gap side part is a tooth side part of the belt tooth part. It is almost similar The In a transmission state where a pulley is wound around the belt and tension is applied to the belt The tooth side of the belt tooth The pressure angle at each position in the tooth height direction is configured to be substantially equal.
[0033]
As described above, with a toothed belt having a convex arc tooth side surface portion, if the pressure angle is configured to be large within an appropriate range, the contact with the pulley tooth groove portion can be slowed, so the speed variation as the belt itself is reduced. Although it has the effect of reducing, it can exhibit a much larger effect by combining with the pulley tooth groove shape. That is, as a prior art aiming at reducing the speed unevenness by combining the belt tooth shape and the pulley tooth groove shape, there is the above-mentioned Japanese Patent Application Laid-Open No. 64-74341. As described above, the backlash between the belt tooth portion and the pulley tooth groove portion is gradually increased from the tooth tip portion toward the tooth tip side (that is, the pulley tooth groove side surface is larger than the pressure angle on the belt tooth side surface). By reducing the pressure angle, the aim is to suppress the interference of the belt teeth on the pulley tooth groove during biting (see FIG. 21).
[0034]
However, in this configuration, interference hardly occurs in the no-load transmission state, but in reality, in the normal transmission state as described above, the belt tooth portion of the pulley tooth groove portion is affected by the applied load torque. Since it bites in a position slightly delayed from the position, the side surface of the tooth portion on the rear side in the running direction of the belt tooth portion comes into contact with the side surface of the pulley tooth groove portion and then slips. At this time, as in the conventional example, if the pressure angle on the pulley tooth groove side is made smaller than the pressure angle on the belt tooth side surface, the belt tooth side surface comes into contact with the apex arc portion of the pulley tooth groove portion, and the belt tooth portion is It is bitten while being pushed up by the crest arc portion of the pulley tooth groove (see FIG. 5B). As a result, the belt cannot slide smoothly into the pulley tooth groove, and the belt pitch line is pushed up, resulting in increased speed unevenness. Actually, in the speed unevenness analysis using the finite element method, the speed unevenness deteriorates for the same pressure angle of the belt and the pulley.
[0035]
On the other hand, according to the structure of the invention of claim 11, the pressure angle at each position in the tooth height direction between the side surface of the belt tooth portion and the tooth groove side surface of the pulley tooth groove portion is substantially equal. Since the tooth side surface contacts the pulley tooth groove portion side surface uniformly and the belt tooth portion slides smoothly into the pulley tooth groove portion, the belt pitch line cannot be pushed up (see FIG. 5A). Therefore, coupled with the fact that the pressure angle on the side surface of the belt tooth portion is larger than before and the contact between the side surface of the belt tooth and the side surface of the pulley tooth groove is slow, unevenness in the speed of the belt can be minimized.
[0036]
In the invention of claim 12, the toothed belt of claim 10 is provided. And double As a toothed belt transmission device in combination with a toothed pulley having a plurality of pulley tooth groove portions, each pulley tooth groove portion is a tooth crest composed of a substantially arcuate surface arranged symmetrically with respect to the center line in the tooth groove width direction. Connect the arcuate part, the tooth gap side part composed of a substantially arcuate concave surface provided symmetrically with respect to the center line in the tooth gap width direction, and the tooth gap side parts. The circular arc surface portion is formed of a substantially circular arc surface provided in this manner, and the tooth groove bottom portion is formed of a single flat surface portion formed of a substantially flat surface so as to connect the two circular arc surface portions. And above The tooth gap side part is a tooth side part of the belt tooth part. It is almost similar The In a transmission state where a pulley is wound around the belt and tension is applied to the belt The tooth side of the belt tooth The pressure angle at each position in the tooth height direction is configured to be substantially equal, and the belt tooth tip portion and the pulley tooth groove bottom portion are in contact with each other.
[0037]
In this way, the toothed belt in which the tooth tip portion of the belt tooth portion is provided on a substantially flat surface and the toothed pulley in which the tooth groove bottom portion of the pulley tooth groove portion is provided on a substantially flat surface are combined, and the two flat portions are in contact with each other. As a result, the entire flat surface of the tooth tip portion of the belt tooth portion can be received by the flat surface portion of the tooth groove bottom portion of the pulley tooth groove portion in a wide area in a state where the belt is fully engaged with the pulley. For this reason, the belt core line position (pitch line) at the time of complete meshing can be made more stable, and the uneven speed of the belt can be further reduced.
[0038]
In the invention of claim 13, the toothed belt of claim 9 above. And double As a toothed belt transmission device in combination with a toothed pulley having a plurality of pulley tooth groove portions, each pulley tooth groove portion is a tooth crest composed of a substantially arcuate surface arranged symmetrically with respect to the center line in the tooth groove width direction. An arc portion, a tooth gap side surface portion made of a substantially arcuate concave surface provided symmetrically with respect to the center line in the tooth gap width direction, and the tooth groove side surface portions are continuous with each other. And is configured by a tooth groove bottom portion having one arc surface having a center on the pulley tooth width direction center line and having a radius larger than the arc radius of the belt tooth tip portion. And above The tooth gap side part is a tooth side part of the belt tooth part. It is almost similar and in a transmission state where a pulley is wound around the belt and tension is applied to the belt. The tooth side of the belt tooth The pressure angle at each position in the tooth height direction is substantially equal, and the belt tooth tip and the pulley tooth groove bottom are in contact with each other.
[0039]
As described above, the tooth bottom portion of the pulley tooth groove portion is configured by an arc surface having a radius larger than the arc radius of the tooth tip portion of the belt tooth portion. Can be received over a wide area of the arc surface of the pulley tooth groove bottom, and the same effect as described above can be obtained.
[0040]
Furthermore, according to the present invention, when the belt is engaged with the pulley, the side surface of the belt tooth portion smoothly slides on the side surface of the pulley tooth groove portion, the tooth tip portion of the belt tooth portion is the tooth side surface portion, and the pulley tooth groove portion. Since the bottom of the tooth groove is an arc surface continuously provided with the side surface of the tooth groove, not only the side of the belt tooth but also the tooth tip until the moment when the belt and the pulley are fully engaged. Even the portion slides smoothly into the bottom portion of the pulley tooth groove, so that the vertical amount of the pitch line hardly occurs and the speed unevenness can be extremely reduced.
[0041]
According to the fourteenth aspect of the present invention, the toothed belt transmission device is provided as office equipment, and a carriage is attached to the toothed belt. As a result, when printing is performed by moving the carriage during operation of the toothed belt transmission device, the speed fluctuation of the carriage due to uneven speed of the belt is reduced, so that the printing accuracy and image quality by the carriage can be improved. .
[0042]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
FIG. 3 shows an overall configuration of the toothed belt transmission device A according to the first embodiment of the present invention, and this transmission device A is installed in office equipment typified by a printer or a copying machine. In FIG. 3, reference numeral 1 denotes a driving pulley made of a toothed pulley, 2 denotes a similar driven pulley, and these pulleys 1 and 2 are arranged facing each other in the horizontal direction, for example. A toothed belt 10 is wound between the pulleys 1 and 2 in a meshed state, and a carriage 24 equipped with a printing mechanism (not shown) such as ink or hammer is attached to the lower span of the toothed belt 10. The carriage 24 is reciprocated between the pulleys 1 and 2 by moving and moving the toothed belt 10 by rotating the drive pulleys 1 and 2 forward or backward. I have to.
[0043]
As shown in FIG. 2 in an enlarged manner, the driving or driven pulleys 1 and 2 comprising the above-mentioned toothed pulleys are provided with a plurality of pulley tooth groove portions 3, 3,... Only one is shown). Each pulley tooth groove portion 3 includes a pair of tooth top arc portions 4 and 4 made of arc surfaces having an arc radius r1P arranged symmetrically with respect to the center line C1 of the tooth groove width direction, and both the tooth top arc portions 4 4 and symmetrically with respect to the tooth gap width direction center line C1 and in the vicinity of the pitch circle PC (the arc surface of the tooth side surface portion 15 in the tooth portion 13 of the belt 10 meshing with the pulleys 1 and 2 as will be described later). 1 consisting of a concave circular arc surface having a central point O1P at the same position as the central point O1B) and having an arc radius RP (> RB) slightly larger than the arc radius RB of the tooth side surface portion 15 of the belt tooth portion 13 described later. A pair of tooth gap side portions 5 and 5 and a tooth groove bottom portion 6 provided so as to be continuous with both tooth groove side portions 5 and 5 are formed. , 5 are arcuate surface portions 7, 7 each having a substantially arcuate surface provided to connect each other, It consists of one flat surface portion 8 formed of a substantially flat surface provided so as to connect both the arc surface portions 7 and 7 (in FIG. 2, the outer periphery of the pulleys 1 and 2 is easy to understand. Is shown deployed with the belt 10).
[0044]
On the other hand, the toothed belt 10 includes a belt body 11 made of an elastic material as shown in an enlarged view in FIG. The belt body 11 is preferably made of rubber or polyurethane, and may be made of other materials such as synthetic resin. In the case of rubber, chloroprene rubber may be used, and NBR, SBR, EPDM, etc. may be used, and the hardness of the rubber is preferably about 65 to 85 ° according to JIS-A. When the belt body 11 is made of polyurethane, the polyurethane is thermosetting and ether-based, but may be thermoplastic or ester-based.
[0045]
Further, a core wire (not shown) as a tensile body is embedded on the pitch line PL of the belt body 11. This core wire is mainly made of glass fiber or aramid fiber, regardless of whether the belt body 11 is made of rubber or polyurethane, and may be a fiber such as carbon or PBO. Moreover, in order to reduce the power consumption of office equipment, a thin core wire is desirable so as to reduce the loss torque.
[0046]
Further, in view of reducing the speed unevenness of the belt 10, in order to stably maintain the pitch line PL of the belt 10, the bending rigidity of the belt 10 is reduced, and the tooth pitch when a load is applied. Considering the point of increasing the tensile elastic modulus of the belt 10 in order to reduce the meshing interference by maintaining the PB and to quickly attenuate the speed fluctuation at the start-up of the office equipment, it is necessary to use a high elastic core. Good.
[0047]
On the land line LL of the belt main body 11, the tooth width W (between the intersecting positions of the land line LL and an arc extension line in the tooth root direction of both tooth side surfaces 15, 15 of the belt tooth portion 13 to be described later). .. (Only one is shown) is formed at a constant tooth pitch PB in the belt length direction, and is formed on the bottom surface of the belt main body 11 between the teeth 13 and 13. The land portion 12 is provided on the land line LL. The pitch PB of the belt tooth portion 13 is set to PB = 1.25 W to 1.5 W with respect to the root width W, and particularly preferably PB = 1.37 W to 1.47 W.
[0048]
When the belt main body 11 is made of rubber as described above, a woven fabric (not shown) made of synthetic fiber is attached to the surface of the tooth portion 13. The woven fabric is preferably a polyamide fiber, but may be a polyester fiber. The woven fabric is usually subjected to adhesion treatment such as RF treatment, epoxy treatment, RFL treatment, and is treated with glue rubber. This glue rubber treatment may be performed on both the front and back sides of the woven fabric. In particular, in the application of office equipment, it dislikes the scattering of rubber powder from the surface of the belt 10 and, from the purpose of reducing the speed unevenness of the belt 10. Since the friction coefficient of the surface of the belt 10 needs to be low, it is preferable not to perform rubber treatment on the side that becomes the surface of the tooth portion 13.
[0049]
On the other hand, when the belt main body 11 is made of polyurethane, the woven fabric is not provided on the surface of the tooth portion 13, and only the core wire is embedded in the belt main body 11.
[0050]
The feature of the present invention resides in the shape of each belt tooth portion 13 and pulley tooth groove portion 3 described above. That is, as shown in FIG. 1, each belt tooth portion 13 is located symmetrically with respect to the tooth width direction center line C <b> 2 (center line in the belt length direction) of the belt tooth portion 13 on both sides in the belt length direction. A pair of tooth root portions 14, 14 consisting of circular arc surfaces of a predetermined radius r 1 B continuous with the land portion 12, and the tooth widths positioned on the side surfaces of the tooth portion 13 continuously with these tooth root portions 14, 14. A pair of tooth side surfaces 15, 15 that are provided symmetrically with respect to the direction center line C <b> 2 and that are convex arc surfaces having an arc radius RB, and arc-shaped tooth tips of the arc surfaces of both tooth side surfaces 15, 15. It is located on the tooth root side (inner side) with respect to the side extension line 15a, and is composed of a tooth tip portion 16 provided so that both tooth side surface portions 15 and 15 are continuous with each other. A portion provided continuously to the side surface portions 15 and symmetrically with respect to the center line C2 in the tooth width direction. A circular surface 17, 17 a substantially arcuate surface having a radius R2B, is composed of a flat portion 18 of one of the substantially plane surfaces provided to be continuous both of these circular surface 17, 17 to each other.
[0051]
The center point O1B of the arc surface of each tooth side surface portion 15 is preferably located on or near the pitch line PL of the belt 10. Further, the arc radius RB of the arc surface of each tooth side surface portion 15 is preferably set to RB = 0.7 W to 1.5 W, in particular, RB = 0.8 W to 1.3 W, and further RB = 0. .9 W to 1.1 W is preferable.
[0052]
The 0.3 W pressure angle θB at the reference position D, which is 0.3 W away from the land line LL in the tooth height direction in the tooth side surface portion 15 on the side surface of the belt tooth portion 13 of the toothed belt 10, is θB = 26 to 39. Is desirably θB = 28 to 35 °, of which θB = 29 to 33 ° is preferable, and the optimum value is θB = 31 ° (in the illustrated example).
[0053]
In addition, as shown in FIG. 2, the side surface (side surface in the tooth width direction) of the belt tooth portion 13 and the side surface of the pulley tooth groove portion 3 (side surface in the tooth groove width direction) are substantially similar to each other. The pressure on the side surface of the belt tooth portion 13 at each position in the tooth height direction of each side surface of the belt tooth portion 13 and the pulley tooth groove portion 3 in an actual transmission state where the belt 10 is wound around the pulleys 1 and 2 and tension is applied to the belt 10. The angle and the pressure angle of the side surface of the pulley tooth groove portion 3 are substantially equal, and the tooth tip portion 16 of the belt tooth portion 13 and the tooth groove bottom portion 6 of the pulley tooth groove portion 3 are in contact with each other.
[0054]
In this embodiment, as shown in FIG. 4, when each tooth portion 13 of the toothed belt 10 is engaged with each tooth groove portion 3 of the driving pulley 1 formed of a toothed pulley, the belt teeth are affected by the applied load torque. Since the portion 13 is engaged at a position slightly delayed from the position of the pulley tooth groove portion 3, the belt tooth portion 13 is moved after the side surface of the tooth portion 13 in the running direction of the belt tooth portion 13 contacts the side surface of the pulley tooth groove portion 3. Slide into the pulley tooth groove 3.
[0055]
At that time, the belt pitch line PL moves up and down in the direction perpendicular to the belt span in the span of the belt 10 (the portion not wrapped around the pulley 1), thereby causing uneven meshing speed and the amount of vertical movement of the pitch line PL. Is determined by a reaction force generated when the belt tooth portion 13 slides into the pulley tooth groove portion 3 and a component force of the belt tension generated when the belt 10 is pushed upward by the reaction force. The further away from the complete meshing position between the belt tooth portion 13 and the pulley tooth groove portion 3, the smaller the belt tension component, the larger the push-up amount of the pitch line PL, and the contact of the belt tooth portion 13 with the pulley tooth groove portion 3 becomes. If it is early, the speed unevenness will increase.
[0056]
Therefore, in the conventional toothed belt 10, as shown in FIG. 4B, the 0.3 W pressure angle θB on the side surface of the belt tooth portion 13 is small (θB = 20.8 to 25.3 °). Whereas the side surface of the belt tooth portion 13 quickly contacts the side surface of the pulley tooth groove portion 3, in this embodiment, the 0.3 W pressure angle θB is θB ≧ 26 ° as shown in FIG. Therefore, the contact of the belt tooth portion 13 with the side surface of the pulley tooth groove portion 3 is delayed, and this can reduce the speed unevenness of the belt 10.
[0057]
On the other hand, the amount of movement of the belt span is determined by the reaction force that slides after the side surface of the belt tooth portion 13 comes into contact with the side surface of the pulley tooth groove portion 3 and the component force of the belt tension. If the angle θB is too large, the component in the vertical direction (direction perpendicular to the belt span) of the reaction force generated when the belt tooth portion 13 slides into the pulley tooth groove portion 3 becomes too large to easily slip and the belt pitch. The line PL is pushed up, and the speed unevenness of the belt 10 increases. In this embodiment, since the 0.3 W pressure angle θB is θB ≦ 39 °, the belt tooth portion 13 smoothly enters the pulley tooth groove portion 3. As a result, the belt 10 can slip, and the increase in the speed unevenness of the belt 10 can be suppressed. That is, by setting the optimum range of the 0.3 W pressure angle θB to θB = 26 to 39 °, the speed unevenness of the belt 10 can be reduced as much as possible.
[0058]
Further, in this embodiment, since the pressure angle at each position in the tooth height direction of the side surface of the belt tooth portion 13 and the side surface of the pulley tooth groove portion 3 is substantially equal, as shown in FIG. The side surface of the portion 13 uniformly contacts the side surface of the pulley tooth groove portion 3 and the belt tooth portion 13 smoothly slides into the pulley tooth groove portion 3. Therefore, as shown in FIG. 5B, the side surface of the belt tooth portion 13 is the side surface of the pulley tooth groove portion 3 as in the case where the pressure angle of the pulley tooth groove portion 3 is smaller than the pressure angle of the belt tooth portion 13. The belt tooth portion 13 is not pushed up to the tooth crest arc portion 4 of the pulley tooth groove portion 3 in contact with the tooth crest arc portion 4, and the speed variation of the belt 10 can be further suppressed.
[0059]
Further, the arc radius RB of the tooth side surface portion 15 located on the tooth side surface of the belt tooth portion 13 is RB = 0.7 W to 1.5 W with respect to the tooth root width W on the land line LL. The following effects can be obtained. That is, by increasing the 0.3 W pressure angle θB as described above, the contact of the belt tooth portion 13 with the pulley tooth groove portion 3 is slowed when the belt tooth portion 13 is engaged with the pulley tooth groove portion 3, and this However, even if the tooth profile has the same 0.3 W pressure angle θB, the slip of the belt tooth portion 13 to the pulley tooth groove portion 3 by the arc radius RB of the tooth side surface portion 15 of the tooth shape can be reduced. Since the ease of loading is different, it affects the speed unevenness. In other words, when the belt 10 is engaged with the pulleys 1 and 2 and the land portion 12 of the belt 10 is wound around the crests of the pulleys 1 and 2, the belt 10 is wound around the pulleys 1 and 2 in an arc shape. When the belt tooth portion 13 bites into the pulley tooth groove portion 3 after the portion 12 is wound, the belt tooth portion 13 uses the point on the pitch line PL near the tooth base on the front side of the tooth traveling direction as a fulcrum (rotation center) as a pulley. Biting into the tooth gap 3. At this time, if the arc radius RB of the tooth side surface portion 15 is too large (for example, RB = 1.6 W), the vicinity of the tooth tip portion 16 of the belt tooth portion 13 is the pulley tooth groove portion 3 as shown in FIG. On the other hand, if the arc radius RB of the tooth side surface portion 15 is too small (for example, RB = 0.65 W) while sliding while interfering with the side surface, FIG. ) As shown in FIG. 4, the side surface of the belt tooth portion 13 slides while interfering with the vicinity of the crest arc portion 4 of the pulley tooth groove portion 3, and thus the vicinity of the tooth tip portion 16 of the belt tooth portion 13 or the side surface slides while interfering. The reaction force from the pulleys 1 and 2 generated at the time of biting increases, and the pitch line PL is pushed up to increase the speed unevenness.
[0060]
However, as in this embodiment, if the arc radius RB of the tooth side surface portion 15 of the belt tooth portion 13 is substantially equal to the belt root width W (RB = 0.7 W to 1.5 W), FIG. As illustrated, the interference as described above hardly occurs and can be smoothly slid and the speed unevenness is reduced. Therefore, if the arc radius RB of the tooth side surface portion 15 is within the range of RB = 0.7 W to 1.5 W with respect to the tooth root width W, it is effective for reducing the speed unevenness of the belt 10.
[0061]
Moreover, since the tooth pitch PB of the toothed belt 10 is set to PB = 1.25 W to 1.5 W with respect to the tooth root width W, the following effects are exhibited. That is, in order to reduce the speed unevenness of the belt 10, it is advantageous that the tooth pitch PB of the belt 10 is as small as possible and the number of pulley teeth is large because the polygonal effect is smaller (closer to a circle). If PB = 1.5 W or less, the speed unevenness is smaller than that of the conventional one. On the other hand, when PB is less than 1.25 W, the pulley tooth crest is too narrow, and there is a problem in the strength and workability of the pulleys 1 and 2. For this reason, as in this embodiment, by setting PB = 1.25 W to 1.5 W, the speed unevenness of the belt 10 can be reduced without causing problems of the strength and workability of the pulleys 1 and 2. it can.
[0062]
Furthermore, the substantially flat plane portion 18 is provided on the tooth tip portion 16 of the belt tooth portion 13, while the substantially flat plane portion 8 is provided on the tooth groove bottom portion 6 of the pulley tooth groove portion 3. In a state in which the pulley 10 is completely engaged with the pulleys 1 and 2, the entire flat portion 18 in the tooth tip portion 16 of the belt tooth portion 13 is received by the flat portion 8 in the tooth groove bottom portion 6 of the pulley tooth groove portion 3 in a wide area. Further, it is possible to further stabilize the speed unevenness of the belt 10 by further stabilizing the core line position (pitch line PL) of the belt 10 at the time of complete engagement.
[0063]
As described above, the unevenness of the speed of the belt 10 is reduced as much as possible, so that the printing accuracy and image quality of the office equipment can be improved.
[0064]
Further, since the tooth groove bottom portion 6 of each pulley tooth groove portion 3 in the pulleys 1 and 2 is substantially flat, the tooth groove bottom portion 6 of the pulley tooth groove portion 3 has the same substantially planar shape as the tooth tip portion 16 of the belt tooth portion 13. can do. In the first embodiment, only the tooth groove bottom portion 6 of the pulley tooth groove portion 3 may be formed by an arc surface having a center in the pulley center direction.
[0065]
(Embodiment 2)
7 and 8 show a second embodiment of the present invention (in the following embodiments, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals and detailed description thereof is omitted). In the form, the shape of the belt tooth portion 13 is changed.
[0066]
That is, in this embodiment, as shown in FIG. 8, each pulley tooth groove portion 3 in the pulleys 1 and 2 is a tooth crest arc portion 4 composed of an arc surface arranged symmetrically with respect to the tooth gap width direction center line C <b> 1. 4, tooth gap side surface portions 5, 5 made of concave arc surfaces provided symmetrically with respect to the tooth gap width direction center line C <b> 1 in succession to the tooth crest arc portions 4, 4, and both tooth groove side surfaces It is comprised by the tooth gap bottom part 6 which consists of the circular arc surface parts 7 and 7 and the plane part 8 which were provided so that parts 5 and 5 might continue.
[0067]
On the other hand, as shown in FIGS. 7 and 8, each belt tooth portion 13 of the toothed belt 10 is located symmetrically with respect to the center line C2 in the tooth width direction of the belt tooth portion 13 on both sides in the belt length direction. A pair of tooth root portions 14, 14 consisting of circular arc surfaces of a predetermined radius r 1 B continuous with the land portion 12, and the tooth width direction center line positioned on the side surface of the tooth portion 13 continuously with the tooth root portions 14, 14. A pair of tooth side surfaces 15 and 15 made of a convex arc surface having an arc radius RB provided symmetrically with respect to C2, and both the tooth side surfaces 15 and 15 are provided so as to be continuous with each other. The tooth tip portion 16 is formed of one circular arc surface having an arc radius rTB having a center point O2B on the center line C2 in the tooth width direction of the portion 13.
[0068]
As in the first embodiment, the 0.3 W pressure angle θB at the reference position D of the tooth side surface portion 15 on the side surface of each belt tooth portion 13 is set to θB = 26 to 39 °, preferably θB = 28 to 35 °, of which θB = 29 to 33 ° is preferable, and the optimum value is θB = 31 ° (in the illustrated example).
[0069]
Further, the side surface of the belt tooth portion 13 and the side surface of the pulley tooth groove portion 3 are substantially similar, and in a transmission state in which the belt 10 is wound around the pulleys 1 and 2 and tension is applied to the belt 10, the belt tooth portion 13 and the pulley The pressure angle on the side surface of the belt tooth portion 13 and the pressure angle on the side surface of the pulley tooth groove portion 3 at each position in the tooth height direction on each side surface of the tooth groove portion 3 are substantially equal, and the tooth tip portion 16 of the belt tooth portion 13 is formed. And the tooth groove bottom portion 6 of the pulley tooth groove portion 3 are in contact with each other. Other configurations are the same as those of the first embodiment.
[0070]
Therefore, also in this embodiment, the same effect as that of the first embodiment can be obtained. In addition, since the tooth tip portion 16 of each belt tooth portion 13 is formed by one circular arc surface, as shown by a solid line in FIG. 9, the contact of the belt tooth portion 13 with the pulley tooth groove portion 3 is prevented. Compared to the structure of the first embodiment (shown by phantom lines in FIG. 9) in which the speed can be further reduced and the 0.3 W pressure angle θB is simply increased, there is an advantage that the speed unevenness of the belt 10 can be further effectively reduced. is there.
[0071]
(Embodiment 3)
FIG. 10 shows a third embodiment, and in this embodiment, each belt tooth portion 13 of the toothed belt 10 has a tooth tip portion 16 made of one circular arc surface at the tip thereof, as in the second embodiment. Both tooth side surfaces 15, 15 on both sides in the belt length direction are provided so as to be continuous.
[0072]
On the other hand, the tooth groove bottom portion 6 of each pulley tooth groove portion 3 in the pulleys 1 and 2 has a center point O2P on the tooth groove width direction center line C1, and the belt tooth portion 13 Tooth tip 16 It is composed of one circular arc surface having an arc radius rTP slightly larger than the arc radius rTB.
[0073]
In the case of this embodiment, the tooth groove bottom portion 6 of each pulley tooth groove portion 3 is formed by an arc surface having a radius rTP (> rTB) slightly larger than the radius rTB of the arc surface of the tooth tip portion 16 of each belt tooth portion 13. Therefore, when the belt 10 is engaged with the pulleys 1 and 2, the side surface of the belt tooth portion 13 slides more smoothly into the side surface of the pulley tooth groove portion 3. Moreover, the tooth tip portion 16 of the belt tooth portion 13 is an arc surface provided continuously with the tooth side surface portion 15, and the tooth groove bottom portion 6 of the pulley tooth groove portion 3 is provided continuously with the tooth groove side surface portion 5. Because of the circular arc surface, not only the side surface of the belt tooth portion 13 but also the tooth tip portion 16 smoothly slides into the pulley tooth groove bottom portion 6 until the moment when the belt 10 and the pulleys 1 and 2 reach a complete meshing state. It becomes like this. By these actions, the vertical amount of the pitch line PL hardly occurs, and the speed unevenness of the belt 10 can be extremely reduced.
[0074]
Further, the tooth bottom portion 6 of the pulley tooth groove portion 3 is formed by an arc surface having a radius rTP slightly larger than the arc radius rTB of the tooth tip portion 16 of the belt tooth portion 13. Substantially the entire arc surface of the tooth tip portion 16 can be received by a wide area of the arc surface of the tooth bottom portion 6 in the pulley tooth groove portion 3, and the position of the center line of the belt 10 when fully engaged is stabilized. The speed unevenness can be reduced.
[0075]
(Other embodiments)
In the first embodiment, the belt land 12 is in contact with the outer diameter portion of the pulley while the belt 10 is wound around the pulleys 1 and 2 and tension is applied to the belt 10. 11, the belt land portion 12 may not contact the pulley outer diameter portion in the same state.
[0076]
Further, in this case, the land portion 12 of the toothed belt 10 may be an arc surface, but the side surface of the belt tooth portion 13 is formed by tooth base portions 14 and 14 formed of arc surfaces symmetrically arranged with respect to the center line C2 in the tooth width direction. It is good to comprise by the substantially plane connected continuously. That is, in the toothed belt 10 in which the belt main body 11 is made of polyurethane, when the tooth pitch PB of the belt tooth portion 13 is 1.5 mm or less, the size of the recess provided to separate the core wire from the land portion 12 is extremely large. Since it is small and it is difficult to process the mold, the core wire is disposed directly on the land portion 12 without providing the concave portion as described above, but this core wire contacts the outer diameter portion of the pulleys 1 and 2. In order not to be damaged, the land portion 12 of the belt 10 is used in a state where it does not contact the outer diameter portions of the pulleys 1 and 2. Therefore, the position of the core wire can be stabilized by making the land portion 12 of the belt 10 substantially flat as described above.
[0077]
In the above embodiments, the toothed belt 10 and the transmission device A provided in office equipment such as a printer and a copying machine have been described. However, the present invention relates to a toothed belt and transmission other than office equipment. Needless to say, the present invention can also be applied to an apparatus.
[0078]
Moreover, in each said embodiment, the tooth tip part 16 which connects both the tooth side parts 15 and 15 of the belt tooth part 13 has the plane part 18 which consists of a substantially plane at the front-end | tip, and this plane part 18 is each tooth | gear. It is formed so as to be continuously connected to the circular arc surface of the side surface portion 15 by the circular arc surface portion 17 (see FIG. 1), or is continuous with the circular arc surface of both tooth side surface portions 15 and 15 and on the center line C2 in the tooth width direction. Although it is composed of one circular arc surface having a center point (see FIG. 7), other shapes of tooth tip portions can be provided. For example, as shown in FIG. 12 (a), the tooth tip 16 provided with a protrusion 20 at the center of the flat surface 18 or the tooth tip formed with a recess 21 at the center in the tooth width direction as shown in FIG. 12 (b). The portion 16 or the like may be used, and the effect of the present invention is exhibited even if it is any other known tooth tip portion. In short, it is only necessary to provide the tooth tip portion 16 so as to be positioned on the tooth base side (inner side) with respect to the extension line in the tooth tip direction of the arcuate surfaces of the both tooth side surface portions 15 and 15.
[0079]
【Example】
(FEM analysis evaluation)
Next, specific examples will be described. First, the speed unevenness of the toothed belt was analyzed using the FEM analysis method. The FEM analysis was a two-dimensional dynamic analysis using general-purpose software “ABAQUS”. As shown in FIG. 13, the analysis model models two pulleys 1 and 2 of driving and driven pulleys and an endless belt 10 having a tooth portion 13 inside, and after applying tension to the belt 10, the pulley 1 , 2 are rotated. Each shape of the belt tooth portion 13 and the pulley tooth groove portion 3 is formed in accordance with the same shape as in the above embodiment (FIG. 13 illustrates a model formed in accordance with the shape of Embodiment 1). Each constant of the belt material was measured and input with a belt having a tooth pitch of 2.117 mm and its constituent materials (assuming that the material constant does not change even if the tooth shape changes). The belt body is set to a rectangular plane element, the core wire is set to a beam element, and the surface in contact with the pulleys 1 and 2 is an interface element in consideration of friction. The pulley surface was modeled as a rigid surface. FIG. 14 shows the main part of the analysis model that is meshed during the analysis by the FEM analysis method. FIG. 14A shows the analysis model of the embodiment of the present invention, and FIG. 14B shows the conventional model. Each example analysis model is shown.
[0080]
Then, the velocity irregularity data was obtained by outputting the velocity at one point on the belt pitch line. The data is shown in FIG. FIG. 15A shows an example of the present invention (corresponding to Embodiment 1 of the present invention) in which the belt tooth portion has a flat surface portion formed of one substantially flat surface at the tooth tip portion, and the 0.3 W pressure angle is 31 °. FIG. 15B shows data of a conventional example (0.3 W pressure angle is 25.3 °).
[0081]
Further, when the relationship between the 0.3 W pressure angle of the belt tooth portion and the speed unevenness (belt speed fluctuation value) was obtained from this data, the result shown in FIG. 16 was obtained. In FIG. 16, the fluctuation value of the belt speed is represented by an index with the above conventional example being “1.0”. Further, in FIG. 16, the solid line indicates that the belt tooth portion has a tooth shape having a tooth tip portion formed of one substantially flat surface, of which 0.3W pressure angle is 26 to 39 °. This is an example of the invention. On the other hand, the broken line corresponds to the second embodiment in which the belt tooth portion is provided so as to be continuous between both tooth side surface portions and has a tooth tip portion formed of one circular arc surface having a center point on the center line in the tooth width direction. The example of this invention is shown.
[0082]
(Table evaluation)
On the other hand, a transmission test composed of a belt and a pulley was produced, and a bench test was also performed in which the speed variation of the belt was measured with a measuring device. That is, as an example of the present invention, two toothed belts having different pressure angles (0.3 W pressure angle = 29.2 °, 31.1 °) in the configuration of the second embodiment shown in FIG. 2) As a conventional example, a toothed belt having a tooth tip portion having one substantially flat surface and a 0.3 W pressure angle of the tooth side surface portion of 25.3 ° was made. The respective dimensions are as shown in Table 1 below. The dimension value is expressed as an index with the belt tooth pitch (2.117 mm) being “1.0”.
[0083]
[Table 1]
Figure 0003838819
[0084]
Specifically, the toothed belt is made of rubber having an arc tooth-shaped tooth portion with a tooth pitch of 2.117 mm, the rubber is chloroprene rubber having a hardness of 70 °, and the core wire is a glass fiber having a diameter of 0.3 mm. Consists of. The woven fabric was made of polyamide wooly yarn, and was subjected to RF treatment and rubber paste treatment only on the back side.
[0085]
And about these toothed belts, the speed nonuniformity at the time of an actual driving | running | working was measured with the belt speed nonuniformity measuring apparatus shown in FIG. This measuring device comprises a drive and driven pulleys 1 and 2 comprising a toothed pulley around which a test toothed belt 10 is wound, and applies a belt tension by a static load DW applied to the driven pulley 2 and is driven pulley. 2 with no load applied, the drive pulley 1 is rotated in the direction of the arrow in the figure, and at a loose side span of the belt 10 at that time, a portion away from the shaft center of the drive pulley 1 by d1 = 10 mm The laser beam 43a is applied to the side of the belt from the probe 43 located at a distance of d2 = 100 ± 2 mm, and the speed unevenness measuring device 44 measures the speed unevenness of the belt 40 based on the output signal of the probe 43. The frequency is analyzed by the FFT 45, taken into the personal computer 46, and the data is printed by the printer 47. FIG. 18 shows the measurement data of the speed unevenness measuring device, and FIG. 19 shows the data obtained by analyzing the frequency of the speed unevenness of the belt 10 (FIG. 19 (a) shows Example 2 of the present invention, and FIG. 19 (b) shows the present invention. Conventional examples are shown). FIG. 20 shows the relationship between the belt tooth portion 0.3 W pressure angle and the speed unevenness obtained from the belt speed unevenness measurement data. Incidentally, the fluctuation value of the belt speed in FIG. 20 is also an index value in which the conventional example (0.3 W pressure angle 25.3 °) is “1.0”.
[0086]
As is apparent from FIG. 16 above, if the 0.3 W pressure angle on the side surface of the belt tooth is 26 to 39 °, the belt has a 0.3 W pressure angle of 25.3 ° as compared to the conventional example. It was confirmed that the non-uniformity of speed was reduced. In particular, if the 0.3 W pressure angle is set to 28 to 35 °, and further set to 29 to 33 °, the belt speed unevenness is greatly reduced, and 31 ° is found to be an optimum value.
[0087]
【The invention's effect】
As described above, in claim 1, For light load transmission The tooth root part of each belt tooth part of the toothed belt and the tooth side part made of a convex substantially arc surface are arranged symmetrically with respect to the center line in the tooth width direction of the belt tooth part. The tooth tip portion of the belt tooth portion is arranged with respect to the tooth width W on the land line by arranging the tooth tip portion continuous between the side surface portions from the tooth tip side extension line of the arc surface of the tooth side surface portion. In this case, the 0.3 W pressure angle at the reference position 0.3 W away from the land line in the tooth height direction is set to 26 to 39 °, A plurality of pulleys having a tooth groove side surface that is substantially similar to the tooth side surface part and has a pressure angle at each position in the tooth height direction substantially equal to the tooth side surface part in a transmission state in which tension is applied. Wound around a toothed pulley provided at a constant pitch on the outer diameter line It was. In the invention of claim 2, the 0.3 W pressure angle is set to 28 to 35 °. Furthermore, in the invention of claim 3, the pressure angle is set to 29 to 33 °. Therefore, according to these inventions, when the belt tooth portion is engaged with the pulley tooth groove portion, the side surface of the belt tooth portion is brought into slow contact with the side surface of the pulley tooth groove portion, and the belt tooth portion is generated when the belt tooth portion slides into the pulley tooth groove portion. The vertical component of the reaction force can be reduced and can be easily slid. Therefore, the speed unevenness of the toothed belt is greatly reduced, and it is represented by a printer. Drives the toothed belt under light load transmission A practically excellent effect of improving the printing accuracy and image quality of office equipment can be obtained.
[0088]
In the invention of claim 4, the arc radius of the tooth side surface portion of the belt tooth portion is set to 0.7 W to 1.5 W. Moreover, in invention of Claim 5, the circular arc radius of the said tooth | gear side part was 0.8W-1.3W. Further, in the invention of claim 6, the arc radius is set to 0.9 W to 1.1 W. According to these inventions, when the belt land portion is caught in the pulley tooth groove after the belt land portion is wound around the pulley tooth crest portion, the vicinity of the tooth tip of the belt tooth portion is the pulley tooth. The belt side surface and the belt tooth side surface are prevented from interfering with each other near the pulley crest arc, so that the belt tooth portion can be smoothly slid into the pulley tooth groove portion and the pitch line is prevented from being pushed up. The speed unevenness can be further reduced.
[0089]
In invention of Claim 7, the tooth pitch of the said belt tooth part was 1.25W-1.5W. In the invention of claim 8, the tooth pitch is set to 1.37W to 1.47W. According to these inventions, it is possible to increase the number of pulley teeth and reduce the belt speed unevenness due to the polygonal effect, while ensuring the pulley strength and workability.
[0090]
According to the ninth aspect of the present invention, the tooth portion of the belt tooth portion is constituted by one arc surface that is continuous with the arc surface of both tooth side surface portions and has a center point on the center line in the tooth width direction. It is possible to further reduce the belt speed unevenness by further slowing the contact of the belt portion with the pulley tooth groove portion.
[0091]
According to the invention of claim 10, the tooth tip portion of the belt tooth portion is provided so as to connect both the arc surface portions to the arc surface portion formed of a substantially arc surface provided so as to be continuous with the arc surfaces of the both side surface portions. When the driven pulley is used as a flat pulley in the application of the printer and the tip portion of the belt tooth portion is in direct contact with the outer diameter portion of the flat pulley by being configured with one flat portion made of a substantially flat surface, The substantially flat belt tooth tip portion can apply a load over a wide area to stabilize the position of the pitch line, and the speed unevenness of the toothed belt can be reduced.
[0092]
According to invention of Claim 11, as a toothed belt transmission device which combines the toothed belt of Claims 1-10 and a toothed pulley, the crest arc which consists of the circular arc surface of each pulley tooth groove part of a toothed pulley And a tooth gap side surface portion made of a concave arcuate surface are arranged symmetrically with respect to the center line in the width direction of the tooth gap, and a tooth groove bottom portion is provided so as to connect both tooth groove side surfaces, The tooth groove side surface of the pulley tooth groove Tooth side surface of belt tooth When The pressure angle of the side surface of the belt tooth portion and the pulley at each position in the tooth height direction of each side surface of the belt tooth portion and pulley tooth groove portion with the belt wound around the pulley and tension is applied to the belt. By making the pressure angle on the side surface of the tooth groove portion substantially equal, when the belt tooth portion is engaged with the pulley tooth groove portion in the transmission state, the belt tooth side surface uniformly contacts the pulley tooth groove side surface and the belt tooth portion Slips smoothly into the pulley tooth groove, and the belt pitch line is prevented from being pushed up, and the uneven speed of the belt can be further reduced.
[0093]
According to the invention of claim 12, as a toothed belt transmission device in which the toothed belt of claim 10 and a toothed pulley are combined, the tooth groove bottom part of each pulley tooth groove part of the toothed pulley is formed on both tooth groove side parts. It shall consist of an arcuate surface part consisting of a substantially arcuate surface connecting each other, and a single plane part consisting of a substantially flat surface connecting these arcuate surface parts, The tooth groove side surface of the pulley tooth groove Tooth side surface of belt tooth When The pressure angle of the side surface of the belt tooth portion and the pulley at each position in the tooth height direction of each side surface of the belt tooth portion and pulley tooth groove portion with the belt wound around the pulley and tension is applied to the belt. By making the pressure angle of the side surface of the tooth groove part substantially equal and bringing the belt tooth tip part and the pulley tooth groove bottom part into contact with each other, the belt tooth part flat surface of the tooth part of the belt tooth part is engaged with the pulley. The entire portion can be received in a wide area by the flat surface portion of the tooth groove bottom portion of the pulley tooth groove portion, and the belt core line position at the time of complete meshing can be stabilized to further reduce the belt speed unevenness.
[0094]
According to the invention of claim 13, as a toothed belt transmission device in which the toothed belt of claim 9 and a toothed pulley are combined, the tooth groove bottom part of each pulley tooth groove part of the toothed pulley is arranged on both side surfaces of the tooth groove. It is provided so as to be continuous with each other, and has a single arc surface having a center on the pulley tooth width direction center line and a radius larger than the arc radius of the belt tooth tip, The tooth groove side surface of the pulley tooth groove Tooth side surface of belt tooth When The pressure angle of the side surface of the belt tooth portion and the pulley at each position in the tooth height direction of each side surface of the belt tooth portion and pulley tooth groove portion with the belt wound around the pulley and tension is applied to the belt. By making the pressure angle of the side surface of the tooth groove part substantially equal and bringing the belt tooth tip part and the pulley tooth groove bottom part into contact with each other, the entire tooth tip part of the belt tooth part is obtained with the belt fully engaged with the pulley. In addition to receiving a large area by the pulley tooth groove part, it is possible to smoothly slide not only the side surface of the belt tooth part but also the tooth tip part to the bottom part of the pulley tooth groove until the complete meshing state, further increasing the uneven speed of the belt Can be reduced.
[0095]
According to the fourteenth aspect of the present invention, since the office equipment is equipped with the toothed belt transmission device and the carriage is attached to the toothed belt, the speed fluctuation of the carriage of the office equipment is reduced. Thus, printing accuracy and image quality can be improved.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view showing a tooth portion of a toothed belt according to a first embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view illustrating a state in which a tooth portion of a toothed belt of the toothed belt transmission according to the first embodiment is engaged with a toothed pulley.
FIG. 3 is a front view schematically showing the overall configuration of the toothed belt transmission device.
FIG. 4 is an explanatory view schematically showing a state in which a tooth portion of a toothed belt meshes with a tooth groove portion of a toothed pulley.
FIG. 5 is a view corresponding to FIG. 4 showing a meshing state corresponding to a difference in pressure angle between a tooth side surface of the toothed belt and a tooth groove side surface of the toothed pulley.
6 is a view corresponding to FIG. 4 showing a meshing state according to the size of the arc radius of the tooth side surface portion of the belt tooth portion.
FIG. 7 is a view corresponding to FIG. 1 and showing a tooth portion of a toothed belt according to a second embodiment of the present invention.
FIG. 8 is a view corresponding to FIG.
FIG. 9 is a view corresponding to FIG. 4 schematically showing a state in which the tooth portion of the toothed belt meshes with the tooth groove portion of the toothed pulley in the second embodiment.
FIG. 10 is a view corresponding to FIG.
FIG. 11 is a view corresponding to FIG. 2 showing another embodiment in which the belt land portion does not contact the pulley outer diameter portion in a transmission state in which tension is applied to the belt.
FIG. 12 is a diagram schematically showing a modification of a tooth tip portion of a belt tooth portion.
FIG. 13 is a diagram showing an overall configuration of an analysis model for analyzing belt speed unevenness by an FEM analysis method;
FIG. 14 is a diagram showing a main part of an analysis model.
FIG. 15 is a diagram showing data obtained by analyzing the belt speed unevenness by an FEM analysis method;
FIG. 16 is a diagram showing a relationship between a pressure angle of a belt tooth portion and speed unevenness obtained from belt speed unevenness analysis data.
FIG. 17 is a view showing an apparatus for measuring uneven belt speed.
FIG. 18 is a diagram showing measurement data of a belt speed unevenness measuring apparatus.
FIG. 19 is a diagram showing data obtained by analyzing the frequency of belt speed unevenness.
FIG. 20 is a diagram showing a relationship between a pressure angle of a belt tooth portion obtained from belt speed unevenness measurement data and speed unevenness.
FIG. 21 is a view corresponding to FIG. 2 and showing a state in which a tooth portion of a conventional toothed belt meshes with a toothed pulley.
[Explanation of symbols]
A Toothed belt drive
1, 2 pulley
3 Pulley tooth groove
4 Top crest arc
5 tooth gap side
6 tooth gap bottom
7 Arc surface
8 Flat part
C1 center line in the tooth gap width direction
O2P center point
rTP arc radius
10 Toothed belt
11 Belt body
12 Land
13 Belt teeth
14 Tooth base
15 Tooth side
16 tooth tip
17 Arc surface
18 Flat part
D Reference position
PL pitch line
LL Landline
C2 Tooth width direction center line
O2B center point
rTB Arc radius
θB 0.3W pressure angle
W tooth root width

Claims (14)

軽負荷伝動用の歯付ベルトにおいて、
ピッチライン上に抗張体が埋設されたベルト本体と、
上記ベルト本体のランドライン上に一定ピッチで設けられた複数のベルト歯部とを備え、
上記各ベルト歯部は、歯幅方向中心線に対し対称に配置された略円弧面からなる歯元部と、
上記歯元部に連続して歯部側面に位置しかつ上記歯幅方向中心線に対し対称に設けられた凸形状の略円弧面からなる歯側面部と、
上記両歯側面部の円弧面の歯先側延長線よりも歯元側に位置し、両歯側面部同士を連続するように設けられた歯先部とで構成されており、
上記ランドライン上での歯元幅をＷとしたとき、上記ベルト歯部の歯側面部においてランドラインから歯高さ方向に０．３Ｗ離れた基準位置での圧力角が２６〜３９°であり、
上記歯側面部と略相似形でかつ張力の付与された伝動状態において、該歯側面部と歯高さ方向の各位置での圧力角が略等しい歯溝側面部を有する複数のプーリ歯溝部がプーリ外径ライン上に一定ピッチで設けられた歯付プーリに巻き付けられることを特徴とする歯付ベルト。 In a toothed belt for light load transmission,
A belt body in which a tensile body is embedded on the pitch line;
A plurality of belt teeth provided at a constant pitch on the land line of the belt body,
Each of the belt tooth portions is a tooth root portion formed of a substantially arc surface arranged symmetrically with respect to the center line in the tooth width direction;
A tooth side surface portion comprising a convex substantially arcuate surface located on the side surface of the tooth portion continuously to the tooth base portion and provided symmetrically with respect to the center line in the tooth width direction;
It is located on the tooth base side of the tooth tip side extension line of the arc surface of the both tooth side surface parts, and is composed of a tooth tip part provided so as to continue both tooth side parts.
When the tooth root width on the land line is W, the pressure angle at the reference position 0.3 W away from the land line in the tooth height direction at the tooth side surface portion of the belt tooth portion is 26 to 39 °. The
A plurality of pulley tooth groove portions having tooth groove side portions having substantially the same pressure angle at each position in the tooth height direction as the tooth side surface portion in a transmission state that is substantially similar to the tooth side surface portion and applied with tension. A toothed belt which is wound around a toothed pulley provided at a constant pitch on a pulley outer diameter line . 請求項１の歯付ベルトにおいて、
ベルト歯部の歯側面部の基準位置での圧力角が２８〜３５°であることを特徴とする歯付ベルト。The toothed belt of claim 1,
A toothed belt, wherein a pressure angle at a reference position of a tooth side surface portion of the belt tooth portion is 28 to 35 °. 請求項１の歯付ベルトにおいて、
ベルト歯部の歯側面部の基準位置での圧力角が２９〜３３°であることを特徴とする歯付ベルト。The toothed belt of claim 1,
A toothed belt, wherein a pressure angle at a reference position of a tooth side surface portion of the belt tooth portion is 29 to 33 °. 請求項１〜３のいずれか１つの歯付ベルトにおいて、
ベルト歯部の歯側面部の円弧半径ＲＢがＲＢ＝０．７Ｗ〜１．５Ｗであることを特徴とする歯付ベルト。The toothed belt according to any one of claims 1 to 3,
A toothed belt, wherein an arc radius RB of a tooth side surface portion of the belt tooth portion is RB = 0.7 W to 1.5 W. 請求項１〜３のいずれか１つの歯付ベルトにおいて、
ベルト歯部の歯側面部の円弧半径ＲＢがＲＢ＝０．８Ｗ〜１．３Ｗであることを特徴とする歯付ベルト。The toothed belt according to any one of claims 1 to 3,
A toothed belt, wherein an arc radius RB of a tooth side surface portion of the belt tooth portion is RB = 0.8 W to 1.3 W. 請求項１〜３のいずれか１つの歯付ベルトにおいて、
ベルト歯部の歯側面部の円弧半径ＲＢがＲＢ＝０．９Ｗ〜１．１Ｗであることを特徴とする歯付ベルト。The toothed belt according to any one of claims 1 to 3,
A toothed belt, wherein an arc radius RB of a tooth side surface portion of the belt tooth portion is RB = 0.9 W to 1.1 W. 請求項１〜６のいずれか１つの歯付ベルトにおいて、
ベルト歯部の歯ピッチＰＢがＰＢ＝１．２５Ｗ〜１．５Ｗであることを特徴とする歯付ベルト。The toothed belt according to any one of claims 1 to 6,
A toothed belt, wherein a tooth pitch PB of the belt tooth portion is PB = 1.25 W to 1.5 W. 請求項１〜６のいずれか１つの歯付ベルトにおいて、
ベルト歯部の歯ピッチＰＢがＰＢ＝１．３７Ｗ〜１．４７Ｗであることを特徴とする歯付ベルト。The toothed belt according to any one of claims 1 to 6,
A toothed belt having a tooth pitch PB of the belt tooth portion of PB = 1.37W to 1.47W. 請求項１〜８のいずれか１つの歯付ベルトにおいて、
ベルト歯部の歯先部は、両歯側面部の円弧面と連続しかつ歯幅方向中心線上に中心点を持つ１つの円弧面で構成されていることを特徴とする歯付ベルト。In the toothed belt of any one of Claims 1-8,
The toothed portion of the belt tooth portion is constituted by a single circular arc surface that is continuous with the circular arc surfaces of both tooth side surface portions and has a center point on the center line in the tooth width direction. 請求項１〜８のいずれか１つの歯付ベルトにおいて、
ベルト歯部の歯先部は、両側面部の円弧面に連続するように設けられた略円弧面からなる円弧面部と、両円弧面部を接続するように設けられた略平面からなる１つの平面部とで構成されていることを特徴とする歯付ベルト。In the toothed belt of any one of Claims 1-8,
The tooth tip part of the belt tooth part is an arc surface part formed of a substantially arc surface provided so as to be continuous with the arc surfaces of both side surface parts, and a single plane part comprising a substantially flat surface provided so as to connect both arc surface parts. A toothed belt characterized by comprising: 請求項１〜１０のいずれか１つの歯付ベルトと、複数のプーリ歯溝部を備えた歯付プーリとを組み合わせてなる歯付ベルト伝動装置であって、
上記各プーリ歯溝部は、歯溝幅方向中心線に対し対称に配置された略円弧面からなる歯頂円弧部と、
上記歯頂円弧部に連続して歯溝幅方向中心線に対し対称に設けられた凹形状の略円弧面からなる歯溝側面部と、
上記両歯溝側面部同士を接続するように設けられた歯溝底部とで構成されており、
上記歯溝側面部は、上記ベルト歯部の歯側面部と略相似形であり、ベルトにプーリが巻き付いてベルトに張力が付与された伝動状態において、ベルト歯部の歯側面部と歯高さ方向の各位置での圧力角が略等しく構成されていることを特徴とする歯付ベルト伝動装置。One and toothed belt any of claims 1 to 10, a toothed belt transmission device comprising a combination of a toothed pulley having a pulley tooth groove portion of the multiple,
Each pulley tooth groove part is a tooth crest part formed of a substantially arc surface arranged symmetrically with respect to the center line in the tooth gap width direction,
A tooth gap side surface portion comprising a substantially arc surface of a concave shape provided symmetrically with respect to the center line of the tooth gap width direction in succession to the tooth crest arc portion;
It is composed of a tooth gap bottom portion provided so as to connect the both tooth groove side surfaces,
The grooves side portion is a tooth side portion and the shape similar to the belt tooth portion, Te transmission state odor tension to the belt pulley is wound around the belt has been applied, the tooth side portion of the belt tooth portion and the tooth height A toothed belt transmission device characterized in that pressure angles at respective positions in the vertical direction are substantially equal. 請求項１０の歯付ベルトと、複数のプーリ歯溝部を備えた歯付プーリとを組み合わせてなる歯付ベルト伝動装置であって、
上記各プーリ歯溝部は、歯溝幅方向中心線に対し対称に配置された略円弧面からなる歯頂円弧部と、
上記歯頂円弧部に連続して歯溝幅方向中心線に対し対称に設けられた凹形状の略円弧面からなる歯溝側面部と、
上記両歯溝側面部同士を接続するように設けられた略円弧面からなる円弧面部と、該両円弧面部同士を接続するように設けられた略平面からなる１つの平面部とからなる歯溝底部とで構成されており、
上記歯溝側面部は、上記ベルト歯部の歯側面部と略相似形であり、ベルトにプーリが巻き付いてベルトに張力が付与された伝動状態において、ベルト歯部の歯側面部と歯高さ方向の各位置での圧力角が略等しく構成され、かつベルト歯先部とプーリ歯溝底部とが接触していることを特徴とする歯付ベルト伝動装置。 A toothed belt according to claim 10, a toothed belt transmission device comprising a combination of a toothed pulley having a pulley tooth groove portion of the multiple,
Each pulley tooth groove part is a tooth crest part formed of a substantially arc surface arranged symmetrically with respect to the center line in the tooth gap width direction,
A tooth gap side surface portion comprising a substantially arc surface of a concave shape provided symmetrically with respect to the center line of the tooth gap width direction in succession to the tooth crest arc portion;
A tooth groove comprising a circular arc surface portion formed of a substantially circular arc surface provided so as to connect the side surfaces of both tooth grooves and a single flat surface portion formed of a substantially flat surface provided so as to connect the circular arc surface portions. Consists of a bottom and
The grooves side portion is a tooth side portion and the shape similar to the belt tooth portion, Te transmission state odor tension to the belt pulley is wound around the belt has been applied, the tooth side portion of the belt tooth portion and the tooth height A toothed belt transmission device characterized in that pressure angles at respective positions in the vertical direction are substantially equal, and a belt tooth tip and a pulley tooth groove bottom are in contact with each other. 請求項９の歯付ベルトと、複数のプーリ歯溝部を備えた歯付プーリとを組み合わせてなる歯付ベルト伝動装置であって、
上記各プーリ歯溝部は、歯溝幅方向中心線に対し対称に配置された略円弧面からなる歯頂円弧部と、
上記歯頂円弧部に連続して歯溝幅方向中心線に対し対称に設けられた凹形状の略円弧面からなる歯溝側面部と、
上記両歯溝側面部同士を連続するように設けられ、上記プーリ歯幅方向中心線上に中心を持ちかつベルト歯先部の円弧半径よりも大きい半径を有する１つの円弧面からなる歯溝底部で構成されており、
上記歯溝側面部は、上記ベルト歯部の歯側面部と略相似形であり、ベルトにプーリが巻き付いてベルトに張力が付与された伝動状態において、ベルト歯部の歯側面部と歯高さ方向の各位置での圧力角が略等しく構成され、かつベルト歯先部とプーリ歯溝底部が接触していることを特徴とする歯付ベルト伝動装置。 A toothed belt according to claim 9, a toothed belt transmission device comprising a combination of a toothed pulley having a pulley tooth groove portion of the multiple,
Each pulley tooth groove part is a tooth crest part formed of a substantially arc surface arranged symmetrically with respect to the center line in the tooth gap width direction,
A tooth gap side surface portion comprising a substantially arc surface of a concave shape provided symmetrically with respect to the center line of the tooth gap width direction in succession to the tooth crest arc portion;
A tooth groove bottom portion formed by one arc surface having a center on the pulley tooth width direction center line and having a radius larger than the arc radius of the belt tooth tip portion, provided to be continuous between both tooth groove side surfaces. Configured,
The grooves side portion is a tooth side portion and the shape similar to the belt tooth portion, Te transmission state odor tension to the belt pulley is wound around the belt has been applied, the tooth side portion of the belt tooth portion and the tooth height A toothed belt transmission device characterized in that pressure angles at respective positions in the vertical direction are substantially equal, and a belt tooth tip and a pulley tooth groove bottom are in contact with each other. 請求項１１〜１３のいずれか１つの歯付ベルト伝動装置が装着されていて、
歯付ベルトにキャリッジが取り付けられていることを特徴とする事務用機器。The toothed belt transmission device according to any one of claims 11 to 13 is mounted,
An office machine characterized in that a carriage is attached to a toothed belt.
JP18055399A 1999-06-25 1999-06-25 Toothed belt, toothed belt transmission and office equipment Expired - Fee Related JP3838819B2 (en)

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