JP3554413B2

JP3554413B2 - Auto tensioner

Info

Publication number: JP3554413B2
Application number: JP21789995A
Authority: JP
Inventors: 宏彰今治
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1995-08-25
Filing date: 1995-08-25
Publication date: 2004-08-18
Anticipated expiration: 2015-08-25
Also published as: JPH0960697A

Description

【０００１】
【発明の属する技術分野】
本発明は、無端ベルトや無端チェーンのような動力伝達用の無端伝動帯にプーリやスプロケットのような押圧部材を弾発的に当接させて所定の張力を与えるためのオートテンショナーに関する。
【０００２】
【従来の技術】
かかるオートテンショナーは、例えば実開昭６４−４１７５６号公報、特開平６−１３７３８９号公報により公知である。
【０００３】
上記実開昭６４−４１７５６号公報に記載されたオートテンショナーは、ハウジングの内周面に形成した雌ねじにロッドの外周面に形成した雄ねじを螺合させるとともに、スプリングでハウジングから前進する方向に付勢した前記ロッドの先端に無端ベルトに当接するプーリを支持した構造を有している。そして、無端ベルトの張力変化に伴ってロッドが回転しながらハウジングに対して進退するとき、前進時の荷重と後退時の荷重との間に所定のヒステリシスを与えるべく、前記雌ねじ及び雄ねじのネジ山の形状を前後非対称にしている。
【０００４】
また上記特開平６−１３７３８９号公報に記載されたオートテンショナーは、ハウジングの内部に配置した有底円筒状のバルブスリーブにロッドと一体のプランジャを摺動自在に嵌合させ、バルブスリーブの底部に設けた油室の内外をオリフィス及び前記プランジャに設けた一方向弁を介して連通させ、更にスプリングでハウジングから前進する方向に付勢した前記ロッドの先端に無端ベルトの背面に当接するプーリを支持した構造を有している。そして、無端ベルトの張力変化に伴ってロッドがハウジングに対して進退するとき、一方向弁の開閉により前進時の荷重と後退時の荷重との間に所定のヒステリシスを与えるようになっている。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記前者のオートテンショナーはロッドが回転しながら進退するため、ロッドが回転してもプーリの軸受け部が回転しないように考慮する必要があり、そのために構造が複雑化する問題があった。また上記後者のオートテンショナーは油圧式であるため、作動油の漏れを防止するために取付姿勢が制限されるという問題があった。
【０００６】
本発明は前述の事情に鑑みてなされたもので、構造が簡単で取付姿勢が自由でありながら、ロッドが進退する際の荷重に所定のヒステリシスを与えることが可能なオートテンショナーを提供することを目的とする。
【０００７】
【課題を解決するための手段】
前記目的を達成するために、請求項１に記載された発明は、周壁及び一対の端壁を有する概略筒状のハウジングと、ハウジングに該ハウジングの軸線に沿って進退可能且つ回転不能に支持されたロッドと、ハウジングの内部に収納されて該ハウジングの一方の端壁からロッドを前進させる方向に付勢する弾発部材と、ハウジングの一方の端壁から延出するロッドの一端部に支持されて無端伝動帯の背面に弾発的に当接する押圧部材と、ハウジングの内部に収納されてロッドが前進するときの荷重及び後退するときの荷重間にヒステリシスを与える制動手段とを備えたオートテンショナーであって、前記制動手段はロッドに形成したネジ部に螺合して該ロッドの進退により回転する回転制動体と、ハウジングに固設されて回転制動体に摺接する固定制動体とを備えてなり、前記固定制動体はロッドの他端部が遊嵌する円筒状の部材であって、その一端部においてハウジングの他方の端壁に固定されるとともに、その他端部において回転制動体に摺接し、前記弾発部材はロッドに設けた弾発部材受け部と回転制動体との間に配置されて該回転制動体を固定制動体に圧接する方向に付勢することを特徴とする。
【０００８】
また請求項２に記載された発明は、周壁及び一対の端壁を有する概略筒状のハウジングと、ハウジングに該ハウジングの軸線に沿って進退可能且つ回転不能に支持されたロッドと、ハウジングの内部に収納されて該ハウジングの一方の端壁からロッドを前進させる方向に付勢する弾発部材と、ハウジングの一方の端壁から延出するロッドの一端部に支持されて無端伝動帯の背面に弾発的に当接する押圧部材と、ハウジングの内部に収納されてロッドが前進するときの荷重及び後退するときの荷重間にヒステリシスを与える制動手段とを備えたオートテンショナーであって、前記制動手段はロッドに形成したネジ部に螺合して該ロッドの進退により回転する回転制動体と、ハウジングに固設されて回転制動体に摺接する固定制動体とを備えてなり、前記固定制動体はハウジングの周壁内面から一体に張り出してロッドの他方の端部が遊嵌するフランジ状の部材であり、前記弾発部材はロッドに設けた弾発部材受け部と回転制動体との間に配置されて該回転制動体を固定制動体に圧接する方向に付勢することを特徴とする。
【０００９】
また請求項３に記載された発明は、周壁及び一対の端壁を有する概略筒状のハウジングと、ハウジングに該ハウジングの軸線に沿って進退可能且つ回転不能に支持されたロッドと、ハウジングの内部に収納されて該ハウジングの一方の端壁からロッドを前進させる方向に付勢する弾発部材と、ハウジングの一方の端壁から延出するロッドの一端部に支持されて無端伝動帯の背面に弾発的に当接する押圧部材と、ハウジングの内部に収納されてロッドが前進するときの荷重及び後退するときの荷重間にヒステリシスを与える制動手段とを備えたオートテンショナーであって、前記制動手段はロッドに形成したネジ部に螺合して該ロッドの進退により回転する回転制動体と、ハウジングに固設されて回転制動体に摺接する固定制動体とを備えてなり、前記回転制動体は有底円筒状の部材であって、その底部にロッドのネジ部が螺合するとともに、その開口部がハウジングの他方の端壁に設けた固定制動体に摺接し、前記弾発部材はロッドに設けた弾発部材受け部と回転制動体との間に配置されて該回転制動体を固定制動体に圧接する方向に付勢することを特徴とする。
【００１０】
また請求項４に記載された発明は、周壁及び一対の端壁を有する概略筒状のハウジングと、ハウジングに該ハウジングの軸線に沿って進退可能且つ回転不能に支持されたロッドと、ハウジングの内部に収納されて該ハウジングの一方の端壁からロッドを前進させる方向に付勢する弾発部材と、ハウジングの一方の端壁から延出するロッドの一端部に支持されて無端伝動帯の背面に弾発的に当接する押圧部材と、ハウジングの内部に収納されてロッドが前進するときの荷重及び後退するときの荷重間にヒステリシスを与える制動手段とを備えたオートテンショナーであって、前記制動手段はロッドに形成したネジ部に螺合して該ロッドの進退により回転する回転制動体と、ハウジングに固設されて回転制動体に摺接する固定制動体とを備えてなり、前記ロッドは非円形断面のガイド部を有しており、このガイド部はハウジングの一方の端壁に形成した非円形断面のガイド孔に挿通され、前記弾発部材はロッドに設けた弾発部材受け部と回転制動体との間に配置されて該回転制動体を固定制動体に圧接する方向に付勢することを特徴とする。
【００１１】
また請求項５に記載された発明は、周壁及び一対の端壁を有する概略筒状のハウジングと、ハウジングに該ハウジングの軸線に沿って進退可能且つ回転不能に支持されたロッドと、ハウジングの内部に収納されて該ハウジングの一方の端壁からロッドを前進させる方向に付勢する弾発部材と、ハウジングの一方の端壁から延出するロッドの一端部に支持されて無端伝動帯の背面に弾発的に当接する押圧部材と、ハウジングの内部に収納されてロッドが前進するときの荷重及び後退するときの荷重間にヒステリシスを与える制動手段とを備えたオートテンショナーであって、前記制動手段はロッドに形成したネジ部に螺合して該ロッドの進退により回転する回転制動体と、ハウジングに固設されて回転制動体に摺接する固定制動体とを備えてなり、前記ロッドのネジ部のピッチは軸方向に変化し、前記弾発部材はロッドに設けた弾発部材受け部と回転制動体との間に配置されて該回転制動体を固定制動体に圧接する方向に付勢することを特徴とする。
【００１２】
【発明の実施例の形態】
以下、本発明の実施の形態を、添付図面に示した本発明の実施例に基づいて説明する。
【００１３】
図１〜図４は本発明の第１実施例を示すもので、図１はオートテンショナーの全体側面図、図２は図１の２−２線断面図、図３は図１の３−３線断面図、図４はロッドの変位と荷重との関係を示すグラフである。
【００１４】
図１に示すように、自動車用エンジンのクランク軸の駆動力を発電機等の補器類に伝達する無端ベルトＢの張力を調整するためのオートテンショナーＴは、周壁１の軸方向両端部を端壁２，３により閉塞した円筒状のハウジング４を備える。図２を併せて参照すると明らかなように、ハウジング４の一方の端壁２には円の一部を切り欠いた非円形断面のガイド孔２₁が形成されており、このガイド孔２₁にロッド５のガイド部６が嵌合する。ガイド部６は平坦面６₁を有して前記ガイド孔２₁と同一の断面形状に形成されており、従って、ロッド５のガイド部６は端壁２のガイド孔２₁に沿って摺動可能且つ回転不能に案内される。
【００１５】
ハウジング４から外部に延出するガイド部６の上端にプーリ支持部７がＬ字状に連設されており、このプーリ支持部７にボールベアリング８及びボルト９を介して押圧部材としてのプーリ１０が支持される。プーリ１０は前記無端ベルトＢの背面に当接して回転する。
【００１６】
図１及び図３から明らかなように、ロッド５のガイド部６の下端には弾発部材受け部としてのフランジ部１１を介してネジ部１２が形成される。ネジ部１２の断面形状はガイド部６のそれと同一であるが、その平坦面１２₁がネジ部１２の外周に沿って螺旋状に形成されている。これら平坦面６₁，１２₁を有するガイド部６及びネジ部１２は、転造によって丸棒材から製造することができる。
【００１７】
ハウジング４の端壁２のガイド孔２₁と同一断面形状のネジ孔１３₁を有する円盤状の回転制動体１３がロッド５のネジ部１２に螺合しており、この回転制動体１３の上面とフランジ部１１の下面との間に弾発部材としてのコイルスプリング１４が縮設される。回転制動体１３は好ましくは合成樹脂製である。
【００１８】
有底円筒状に形成された金属製の固定制動体１５が、その底部においてハウジング４の端壁３にボルト１６で固定される。固定制動体１５の内部空間１５₁にはロッド５のネジ部１２が遊嵌するとともに、固定制動体１５の上面と回転制動体１３の下面とが、摺動面Ｐを介して摺接する。前記ネジ部１２、回転制動体１３及び固定制動体１５は本発明の制動手段Ｆを構成する。
【００１９】
次に、前述の構成を備えた本発明の実施例の作用について説明する。
【００２０】
ロッド５は回転制動体１３の上面とフランジ部１１の下面との間に縮設したコイルスプリング１４の弾発力によって前進方向に付勢されており、ロッド５に支持したプーリ１０は無端ベルトＢの背面に当接して該無端ベルトＢに張力を与えている。無端ベルトＢの張力が増加すると、ロッド５はコイルスプリング１４を圧縮しながら、ガイド部６の平坦面６₁を端壁２のガイド孔２₁に案内されて回転することなく後退方向に摺動する。
【００２１】
このとき、オートテンショナーＴが制動手段Ｆを備えていないと仮定すると、ロッド５を後退させるための押圧荷重はコイルスプリング１４の弾発力に等しく、またロッド５が前進するときの前進荷重もコイルスプリング１４の弾発力に等しくなる。従って、制動手段Ｆを備えていない場合には、ロッド５を進退させる荷重はコイルスプリング１４の変形に伴う弾発力だけに依存し、図４に破線ａで示すようにヒステリシスは発生しない。
【００２２】
一方、本発明の如く制動手段Ｆを備えている場合には、ロッド５が後退方向に摺動すると、固定制動体１５の上面に当接して軸方向の移動を規制された回転制動体１３は、ロッド５のネジ部１２との螺合により強制的に回転駆動されるとともに、螺合部に作用する摩擦力により固定制動体１５の上面に押し付けられる。従って、回転制動体１３と固定制動体１５との摺動面Ｐには、コイルスプリング１４の弾発力に基づく面圧に加えて、前記ロッド５の後退方向の摺動に伴う面圧が作用し、摺動面Ｐには回転制動体１３の回転を規制しようとする摩擦力が発生する。ロッド５の後退量が増加するとコイルスプリング１４が圧縮されて弾発力が増加するため、前記摩擦力はロッド５が後退するに伴って増加する。
【００２３】
而して、無端ベルトＢの張力の増加によりロッド５が後退方向に摺動するとき、その後退量の増加に伴って摺動面Ｐに作用する摩擦力が増加するため、回転制動体１３の回転（即ち、ロッド５の後退）が規制される。その結果、図４に実線ｂで示すように、前記破線ａに比べてロッド５の後退時の荷重は増加する。
【００２４】
また、ロッド５が前進方向に摺動すると、回転制動体１３はロッド５のネジ部１２との螺合により前述とは逆方向に強制的に回転駆動される。このとき、前進するロッド５に引かれて回転制動体１３には固定制動体１５から離反するような力が加わるが、その力よりもコイルスプリング１４が回転制動体１３を固定制動体１５に押し付ける力の方が勝っているため、回転制動体１３は固定制動体１５に所定の面圧で摺接し、摺動面Ｐには回転制動体１３の回転を規制しようとする摩擦力が発生する。その結果、コイルスプリング１４の弾発力でロッド５が前進しようとする荷重は、前記摩擦力により相殺され、図４に実線ｃで示すように、ロッド５の前進時の荷重は前記破線ａに比べて小さくなる。
【００２５】
このようにして、制動手段Ｆによりロッド５の進退時の荷重にヒステリシスを与えることができるので、無端ベルトＢの張力が減少した場合にはロッド５を速やかに前進させて無端ベルトＢの弛みを抑えるとともに、無端ベルトＢの張力が増加した場合にはロッド５の後退に所定の抵抗力を与えて無端ベルトＢの振動を抑えることが可能になる。
【００２６】
しかも、このオートテンショナーＴはロッド５が回転せずに進退するため、ロッド５に対するプーリ１０の支持構造が極めて簡単であるばかりか、油圧を使用していないので、作動油の漏れを考慮することなく任意の取付姿勢をとることができる。更に、ハウジング４は周壁１及び一対の端壁２，３で囲まれた概略円筒状に形成されているので、その内部に水や塵が入り難くなっている。従って、錆の発生等によるオートテンショナーＴの作動不良を効果的に防止することができる。
【００２７】
次に、図５に基づいて本発明の第２実施例を説明する。
【００２８】
第２実施例は、回転制動体１３と固定制動体１５との摺動面Ｐが平面でなく、相互に回転自在に嵌合する曲面から構成されている。従って、回転制動体１３が回転する際に、その回転軸線のずれを規制してロッド５のコジリを防止するとともに、摺動面Ｐにおける摩擦力の発生を安定させることができる。
【００２９】
次に、図６に基づいて本発明の第３実施例を説明する。
【００３０】
第３実施例は、固定制動体１５をハウジング４の側壁１内周面にフランジ状に一体成形したもので、これにより部品点数の削減と小型化とが可能になる。
【００３１】
次に、図７に基づいて本発明の第４実施例を説明する。
【００３２】
第４実施例は、回転制動体１３が有底円筒状に形成されており、その上底部に形成したネジ孔１３₁にロッド５のネジ部１２が螺合している。そして回転制動体１３の下端が、固定制動体１５として機能するハウジング４の端壁３に摺接する。この第４実施例によれば、部品点数を更に減少させることができる。
【００３３】
次に、図８に基づいて本発明の第５実施例を説明する。
【００３４】
第５実施例はロッド５のネジ部１２の構造に特徴を有するもので、そのネジ部１２のピッチがフランジ部１１に近い側で小さく、フランジ部１１から遠い側で大きくなるように変化している。ロッド５が後退するとき、その初期には大きなピッチにより回転制動体１３の回転量が小さくなって小さな制動力が発生するが、その後期には小さなピッチにより回転制動体１３の回転量が大きくなって大きな制動力が発生する。従って、ネジ部１２のピッチを軸方向に変化させることにより、ヒステリシスの特性を任意に設定することが可能となる。
【００３５】
次に、図９に基づいて本発明の第６実施例を説明する。
【００３６】
第６実施例は、ロッド５のフランジ部１１にコイルスプリング１４の上端を係止する代わりに、ロッド５に形成した弾性部材受け部としての孔５₁にコイルスプリング１４の上端を係止したものである。この実施例によれば、ロッド５の構造を更に簡略化することができる。
【００３７】
以上、本発明の実施例を詳述したが、本発明は前記実施例に限定されるものでなく、種々の設計変更を行うことが可能である。
【００３８】
例えば、実施例では回転制動体１３を合成樹脂製とし、固定制動体１５を金属製としているが、それらの材質は任意に設定することができる。またロッド５のガイド部６の断面形状及びネジ部１２の断面形状も任意に設定することができる。また実施例では便宜上ハウジング４を一部材として図示しているが、組み立て上の都合から適宜分割することができる。また無端伝動帯を無端チェーンとすることもでき、この場合押圧部材はスプロケットになる。更にまた、押圧部材は無端伝動帯に摺接するスリッパであっても良い。
【００３９】
【発明の効果】
以上のように、請求項１〜請求項５のそれぞれに記載された発明によれば、制動手段はロッドに形成したネジ部に螺合して該ロッドの進退により回転する回転制動体と、ハウジングに固設されて回転制動体に摺接する固定制動体とを備えてなり、弾発部材はロッドに設けた弾発部材受け部と回転制動体との間に配置されて該回転制動体を固定制動体に圧接する方向に付勢するので、ロッドが後退する際の荷重は弾発部材の弾発力と両制動体間に作用する摩擦力との和になり、ロッドが前進する際の荷重は弾発部材の弾発力と両制動体間に作用する摩擦力との差になる。その結果、回転体を支持するロッドが進退する際の荷重に所定のヒステリシスを与えて、無端伝動帯の張力を適切に調節することができる。しかも、ロッドが回転しないので該ロッドに回転体を支持する構造が簡略化されるばかりか、油圧を使用していないので取付姿勢に制約を受けることも無い。更に、ハウジングは周壁及び一対の端壁を有する概略円筒状に形成されているので内部に水や塵が入り難く、錆の発生等による作動不良を効果的に防止することができる。
【００４０】
また特に請求項１に記載された発明によれば、固定制動体はロッドの他端部が遊嵌する円筒状の部材であって、その一端部においてハウジングの他方の端壁に固定されるとともに、その他端部において回転制動体に摺接するので、ロッドのネジ部と干渉することなく回転制動体を固定制動体に摺接させることができる。
【００４１】
また特に請求項２に記載された発明によれば、固定制動体はハウジングの周壁内面から一体に張り出してロッドの他方の端部が遊嵌するフランジ状の部材であるため、部品点数を削減することができる。
【００４２】
また特に請求項３に記載された発明によれば、回転制動体は有底円筒状の部材であって、その底部にロッドのネジ部が螺合するとともに、その開口部がハウジングの他方の端壁に設けた固定制動体に摺接するので、部品点数を更に削減することができる。
【００４３】
また特に請求項４に記載された発明によれば、ロッドは非円形断面のガイド部を有しており、このガイド部をハウジングの一方の端壁に形成した非円形断面のガイド孔に挿通したので、簡単な構造でロッドを摺動可能且つ回転不能に支持することができる。
【００４４】
また特に請求項５に記載された発明によれば、ロッドのネジ部のピッチを軸方向に変化させたので、ロッドの変位に対する回転制動体の回転数を変化させて前記ヒステリシスを任意に設定することができる。
【図面の簡単な説明】
【図１】オートテンショナーの全体側面図
【図２】図１の２−２線断面図
【図３】図１の３−３線断面図
【図４】ロッドの変位と荷重との関係を示すグラフ
【図５】第２実施例に係る、前記図１に対応する図
【図６】第３実施例に係る、前記図１に対応する図
【図７】第４実施例に係る、前記図１に対応する図
【図８】第５実施例に係る、ロッドの側面図
【図９】第６実施例に係る、ロッド及びコイルスプリングの側面図
【符号の説明】
１周壁
２端壁
２₁ ガイド孔
３端壁
４ハウジング
５ロッド
５₁ 孔（弾発部材受け部）
６ガイド部
１０プーリ（押圧部材）
１１フランジ部（弾発部材受け部）
１２ネジ部
１３回転制動体
１４コイルスプリング（弾発部材）
１５固定制動体
Ｂ無端ベルト（無端伝動帯）
Ｆ制動手段
Ｐ摺動面[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an auto-tensioner for applying a predetermined tension by elastically bringing a pressing member such as a pulley or a sprocket into contact with an endless power transmission band for transmitting power such as an endless belt or an endless chain.
[0002]
[Prior art]
Such an automatic tensioner is known, for example, from Japanese Utility Model Application Laid-Open No. 64-41756 and Japanese Patent Application Laid-Open No. 6-137389.
[0003]
The auto-tensioner described in Japanese Utility Model Laid-Open Publication No. 64-41756 discloses a female screw formed on an inner peripheral surface of a housing and a male screw formed on an outer peripheral surface of a rod. A structure is provided in which a pulley that abuts on the endless belt is supported at the tip of the urged rod. When the rod advances and retreats with respect to the housing while rotating due to a change in the tension of the endless belt, the thread of the female screw and the male screw are provided so as to provide a predetermined hysteresis between the load at the time of advance and the load at the time of retreat. Is asymmetrical in the front-rear direction.
[0004]
The auto-tensioner described in the above-mentioned Japanese Patent Application Laid-Open No. 6-137389 has a plunger integrated with a rod slidably fitted to a bottomed cylindrical valve sleeve disposed inside a housing, and is fitted to the bottom of the valve sleeve. The inside and outside of the provided oil chamber are communicated through an orifice and a one-way valve provided in the plunger, and a pulley that contacts the back surface of the endless belt at the tip of the rod urged in the direction of moving forward from the housing by a spring is supported. It has the following structure. When the rod advances and retreats with respect to the housing due to a change in the tension of the endless belt, a predetermined hysteresis is applied between the load at the time of forward movement and the load at the time of retreat by opening and closing the one-way valve.
[0005]
[Problems to be solved by the invention]
However, since the former auto-tensioner advances and retreats while the rod rotates, it is necessary to take into account that the bearing of the pulley does not rotate even if the rod rotates, and thus the structure is complicated. Further, since the latter automatic tensioner is of a hydraulic type, there is a problem that the mounting posture is restricted in order to prevent leakage of hydraulic oil.
[0006]
The present invention has been made in view of the above circumstances, and provides an auto-tensioner capable of giving a predetermined hysteresis to a load when a rod advances and retreats, while having a simple structure and a free mounting posture. Aim.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 has a substantially cylindrical housing having a peripheral wall and a pair of end walls, and is supported by the housing so as to be able to advance and retreat along the axis of the housing and to be unable to rotate. A rod, a resilient member housed inside the housing and biasing the rod forward from one end wall of the housing, and one end of the rod extending from one end wall of the housing. Auto-tensioner having a pressing member that resiliently abuts the rear surface of the endless power transmission band, and a braking unit that is housed inside the housing and provides hysteresis between the load when the rod moves forward and the load when the rod moves backward. Wherein the braking means is screwed into a threaded portion formed on the rod and is rotated by the advance and retreat of the rod, and is fixed to the housing and is in sliding contact with the rotary braking body. It and a constant braking body, the fixed braking member is a cylindrical member to which the other end portion of the rod is loosely fitted, is fixed to the other end wall of the housing at one end, at its other end Sliding contact with the rotating brake, wherein the resilient member is disposed between the resilient member receiving portion provided on the rod and the rotating brake, and biases the rotating brake in a direction of pressing against the fixed brake. Features.
[0008]
According to a second aspect of the present invention, there is provided a substantially cylindrical housing having a peripheral wall and a pair of end walls, a rod supported by the housing so as to be able to advance and retreat along the axis of the housing and to be non-rotatable, And a resilient member for urging the rod in a direction to advance the rod from one end wall of the housing, and a back end of an endless transmission belt supported by one end of a rod extending from one end wall of the housing. An auto-tensioner comprising: a pressing member that resiliently abuts; and a braking device that is housed inside the housing and that provides hysteresis between a load when the rod moves forward and a load when the rod moves backward, wherein the braking device includes: Is provided with a rotary brake which is screwed into a threaded portion formed on the rod and rotates by advancing and retreating of the rod, and a fixed brake which is fixed to the housing and slidably contacts the rotary brake. The fixed brake member is a flange-shaped member and the other end of the rod protrudes integrally from the inner surface of the peripheral wall of the housing is loosely fitted, the resilient member is a rotary braking member Tamahatsu member receiving portion provided on the rod And urges the rotary brake in the direction of pressing against the fixed brake.
[0009]
According to a third aspect of the present invention, there is provided a substantially cylindrical housing having a peripheral wall and a pair of end walls, a rod supported by the housing so as to be able to advance and retreat along the axis of the housing so as not to rotate, and an interior of the housing. And a resilient member for urging the rod in a direction to advance the rod from one end wall of the housing, and a back end of an endless transmission belt supported by one end of a rod extending from one end wall of the housing. An auto-tensioner comprising: a pressing member that resiliently abuts; and a braking device that is housed inside the housing and that provides hysteresis between a load when the rod moves forward and a load when the rod moves backward, wherein the braking device includes: Is provided with a rotary brake which is screwed into a threaded portion formed on the rod and rotates by advancing and retreating of the rod, and a fixed brake which is fixed to the housing and slidably contacts the rotary brake. , The rotating brake member is a bottomed cylindrical member, together with the threaded portion of the rod is screwed to the bottom, sliding on the fixed brake body the opening is provided on the other end wall of the housing, the The resilient member is disposed between the resilient member receiving portion provided on the rod and the rotary brake, and biases the rotary brake in a direction of pressing against the fixed brake.
[0010]
According to a fourth aspect of the present invention, there is provided a substantially cylindrical housing having a peripheral wall and a pair of end walls, a rod supported by the housing so as to be able to advance and retreat along the axis of the housing so as not to rotate, and And a resilient member for urging the rod in a direction to advance the rod from one end wall of the housing, and a back end of an endless transmission belt supported by one end of a rod extending from one end wall of the housing. An auto-tensioner comprising: a pressing member that resiliently abuts; and a braking device that is housed inside the housing and that provides hysteresis between a load when the rod moves forward and a load when the rod moves backward, wherein the braking device includes: Is provided with a rotary brake which is screwed into a threaded portion formed on the rod and rotates by advancing and retreating of the rod, and a fixed brake which is fixed to the housing and slidably contacts the rotary brake. The rod has a guide portion of non-circular cross-section, the guide portion is inserted into the guide hole of non-circular cross-section formed in one end wall of the housing, it said resilient member is resilient provided at the rod The rotary brake is disposed between the member receiving portion and the rotary brake to urge the rotary brake in a direction of pressing against the fixed brake.
[0011]
According to a fifth aspect of the present invention, there is provided a substantially cylindrical housing having a peripheral wall and a pair of end walls, a rod supported by the housing so as to be able to advance and retreat along the axis of the housing so as not to rotate, and an inner portion of the housing. And a resilient member for urging the rod in a direction to advance the rod from one end wall of the housing, and a back end of an endless transmission belt supported by one end of a rod extending from one end wall of the housing. An auto-tensioner comprising: a pressing member that resiliently abuts; and a braking device that is housed inside the housing and that provides hysteresis between a load when the rod moves forward and a load when the rod moves backward, wherein the braking device includes: Is provided with a rotary brake which is screwed into a threaded portion formed on the rod and rotates by advancing and retreating of the rod, and a fixed brake which is fixed to the housing and slidably contacts the rotary brake. , The pitch of the threaded portion of the rod is changed to the axial direction, pressing the resilient member is disposed between the Tamahatsu member receiving portion provided in the rod and the rotating brake body the rotating brake body on the fixed brake body In the direction in which it is driven.
[0012]
Embodiment of the Invention
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0013]
1 to 4 show a first embodiment of the present invention. FIG. 1 is an overall side view of an auto tensioner, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is 3-3 of FIG. FIG. 4 is a graph showing the relationship between the displacement of the rod and the load.
[0014]
As shown in FIG. 1, an auto-tensioner T for adjusting the tension of an endless belt B that transmits the driving force of a crankshaft of an automobile engine to accessories such as a generator is provided at both axial ends of a peripheral wall 1. A cylindrical housing 4 closed by end walls 2 and 3 is provided. As it is apparent Referring also to FIG. 2, the one end wall 2 of the housing 4 has guide holes 2 ₁ a non-circular cross-section, with parts cut away, of a circle is formed, the guide hole 2 ₁ The guide part 6 of the rod 5 is fitted. Guide portion 6 is formed in the same cross-sectional shape and the guide hole 2 ₁ has a flat surface _61, therefore, the guide portion 6 of the rod 5 along the guide holes 2 _first end wall 2 sliding Guided as possible and non-rotatable.
[0015]
A pulley support 7 is connected to the upper end of a guide 6 extending outside from the housing 4 in an L-shape. A pulley 10 as a pressing member is connected to the pulley support 7 via a ball bearing 8 and a bolt 9. Is supported. The pulley 10 rotates in contact with the back surface of the endless belt B.
[0016]
As is clear from FIGS. 1 and 3, a screw portion 12 is formed at the lower end of the guide portion 6 of the rod 5 via a flange portion 11 as a resilient member receiving portion. Cross-sectional shape of the threaded portion 12 is a same as that of the guide portion 6, the planar surface 12 ₁ is formed in a spiral shape along the outer periphery of the threaded portion 12. The guide portion 6 and the screw portion 12 having the flat surfaces 6 ₁ and 12 ₁ can be manufactured from a round bar material by rolling.
[0017]
Disk-shaped rotary braking member 13 having a screw hole 13 ₁ of the guide hole 2 ₁ the same cross-sectional shape of the end wall 2 of the housing 4 are screwed to the screw portion 12 of the rod 5, the upper surface of the rotating brake member 13 A coil spring 14 as a resilient member is contracted and provided between the coil spring 14 and the lower surface of the flange portion 11. The rotation brake 13 is preferably made of a synthetic resin.
[0018]
A metal fixed braking body 15 formed in a cylindrical shape with a bottom is fixed to the end wall 3 of the housing 4 with a bolt 16 at the bottom. With threaded portion 12 of the rod 5 is loosely fitted in the interior space 15 ₁ of the stationary brake member 15, and the lower surface of the upper surface and the rotating brake member 13 of the fixed brake member 15, sliding contact over the sliding surface P. The screw portion 12, the rotary brake 13 and the fixed brake 15 constitute a braking means F of the present invention.
[0019]
Next, the operation of the embodiment of the present invention having the above-described configuration will be described.
[0020]
The rod 5 is urged in the forward direction by the repulsive force of a coil spring 14 contracted between the upper surface of the rotary brake 13 and the lower surface of the flange portion 11, and the pulley 10 supported by the rod 5 is an endless belt B And tension is applied to the endless belt B. The tension of the endless belt B increases, while the rod 5 compresses the coil spring 14, sliding the flat surface ₆₁ of the guide portion 6 in the backward direction without rotating while being guided by the guide hole 2 _first end wall 2 I do.
[0021]
At this time, assuming that the auto-tensioner T does not include the braking means F, the pressing load for retreating the rod 5 is equal to the elastic force of the coil spring 14, and the forward load when the rod 5 advances is also a coil load. It becomes equal to the spring force of the spring 14. Therefore, when the braking means F is not provided, the load for moving the rod 5 forward and backward depends only on the resilience due to the deformation of the coil spring 14, and no hysteresis occurs as shown by the broken line a in FIG.
[0022]
On the other hand, in the case where the braking means F is provided as in the present invention, when the rod 5 slides in the retreating direction, the rotary braking body 13 which is in contact with the upper surface of the fixed braking body 15 and whose axial movement is restricted is restricted. The rod 5 is forcibly driven to rotate by screwing with the screw portion 12 and is pressed against the upper surface of the fixed brake 15 by the frictional force acting on the screwing portion. Therefore, in addition to the surface pressure based on the resilience of the coil spring 14, the surface pressure due to the sliding of the rod 5 in the retreating direction acts on the sliding surface P between the rotary braking member 13 and the fixed braking member 15. However, a frictional force is generated on the sliding surface P to restrict the rotation of the rotation brake 13. When the retraction amount of the rod 5 increases, the coil spring 14 is compressed and the resilience increases, so that the frictional force increases as the rod 5 retreats.
[0023]
Thus, when the rod 5 slides in the retreating direction due to the increase in the tension of the endless belt B, the frictional force acting on the sliding surface P increases with the increase in the amount of retraction. Rotation (that is, retraction of the rod 5) is restricted. As a result, as shown by the solid line b in FIG. 4, the load when the rod 5 is retracted increases as compared with the broken line a.
[0024]
When the rod 5 slides in the forward direction, the rotation braking body 13 is forcibly driven to rotate in a direction opposite to the above by screwing with the screw portion 12 of the rod 5. At this time, a force is applied to the rotary brake 13 by being pulled by the rod 5 moving forward, so as to separate from the fixed brake 15, but the coil spring 14 presses the rotary brake 13 against the fixed brake 15 by the force. Since the force is greater, the rotary brake 13 slides against the fixed brake 15 with a predetermined surface pressure, and a frictional force is generated on the sliding surface P to control the rotation of the rotary brake 13. As a result, the load at which the rod 5 moves forward due to the elastic force of the coil spring 14 is offset by the frictional force. As shown by the solid line c in FIG. It is smaller than that.
[0025]
In this way, the hysteresis can be given to the load when the rod 5 advances and retreats by the braking means F. Therefore, when the tension of the endless belt B decreases, the rod 5 is quickly advanced to reduce the slack of the endless belt B. In addition, when the tension of the endless belt B increases, a predetermined resistance force is applied to the retraction of the rod 5 so that the vibration of the endless belt B can be suppressed.
[0026]
In addition, since the rod 5 moves forward and backward without rotating, the auto tensioner T not only has a very simple structure for supporting the pulley 10 with respect to the rod 5, but also does not use hydraulic pressure. And any mounting posture can be taken. Furthermore, since the housing 4 is formed in a substantially cylindrical shape surrounded by the peripheral wall 1 and the pair of end walls 2 and 3, it is difficult for water and dust to enter the inside. Therefore, malfunction of the auto tensioner T due to rust or the like can be effectively prevented.
[0027]
Next, a second embodiment of the present invention will be described with reference to FIG.
[0028]
In the second embodiment, the sliding surface P between the rotary brake 13 and the fixed brake 15 is not a flat surface, but is formed of a curved surface which is rotatably fitted to each other. Therefore, when the rotation brake 13 rotates, the displacement of the rotation axis can be restricted to prevent the rod 5 from stiffening, and the generation of frictional force on the sliding surface P can be stabilized.
[0029]
Next, a third embodiment of the present invention will be described with reference to FIG.
[0030]
In the third embodiment, the fixed braking member 15 is integrally formed in a flange shape on the inner peripheral surface of the side wall 1 of the housing 4, whereby the number of parts and the size can be reduced.
[0031]
Next, a fourth embodiment of the present invention will be described with reference to FIG.
[0032]
The fourth embodiment, the rotary damping member 13 is formed into a bottomed cylindrical shape, its screw hole 13 ₁ formed in the upper bottom screw portion 12 of the rod 5 is screwed. Then, the lower end of the rotary brake 13 slides on the end wall 3 of the housing 4 functioning as the fixed brake 15. According to the fourth embodiment, the number of components can be further reduced.
[0033]
Next, a fifth embodiment of the present invention will be described with reference to FIG.
[0034]
The fifth embodiment has a feature in the structure of the threaded portion 12 of the rod 5, and the pitch of the threaded portion 12 changes so as to be smaller on the side closer to the flange portion 11 and larger on the side farther from the flange portion 11. I have. When the rod 5 retreats, the rotation amount of the rotary brake 13 is reduced due to the large pitch at the initial stage and a small braking force is generated, but the rotation amount of the rotary brake 13 is increased due to the small pitch in the later period. Large braking force is generated. Therefore, by changing the pitch of the screw portion 12 in the axial direction, it is possible to arbitrarily set the hysteresis characteristics.
[0035]
Next, a sixth embodiment of the present invention will be described with reference to FIG.
[0036]
The sixth embodiment, instead of locking the upper end of the coil spring 14 to the flange portion 11 of the rod 5, that locks the upper end of the coil spring 14 into the hole 5 ₁ as the elastic member receiving portion formed in the rod 5 It is. According to this embodiment, the structure of the rod 5 can be further simplified.
[0037]
Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design changes can be made.
[0038]
For example, in the embodiment, the rotary brake 13 is made of synthetic resin and the fixed brake 15 is made of metal, but these materials can be arbitrarily set. Further, the cross-sectional shape of the guide portion 6 of the rod 5 and the cross-sectional shape of the screw portion 12 can be arbitrarily set. Further, in the embodiment, the housing 4 is illustrated as one member for convenience, but the housing 4 can be appropriately divided for convenience of assembly. In addition, the endless transmission band may be an endless chain, in which case the pressing member is a sprocket. Furthermore, the pressing member may be a slipper that slides on the endless transmission band.
[0039]
【The invention's effect】
As described above, according to the invention described in each of claims 1 to 5 , the braking means is screwed into the threaded portion formed on the rod, and the rotation braking body which rotates by moving the rod forward and backward, and the housing And a fixed braking member that is fixed to the rotating braking member and is in sliding contact with the rotating braking member. The resilient member is disposed between the resilient member receiving portion provided on the rod and the rotating braking member to fix the rotating braking member. Since the rod is urged in the direction of pressing against the brake, the load when the rod retreats is the sum of the elastic force of the resilient member and the frictional force acting between both brakes, and the load when the rod moves forward Is the difference between the resilience of the resilient member and the frictional force acting between the two brakes. As a result, a predetermined hysteresis is given to the load when the rod supporting the rotating body advances and retreats, and the tension of the endless transmission band can be appropriately adjusted. Moreover, since the rod does not rotate, the structure for supporting the rotating body on the rod is simplified, and the mounting posture is not restricted because no hydraulic pressure is used. Further, since the housing is formed in a substantially cylindrical shape having a peripheral wall and a pair of end walls, it is difficult for water or dust to enter the inside, and malfunctions due to rust or the like can be effectively prevented.
[0040]
According to the invention described in claim 1 , the fixed brake body is a cylindrical member into which the other end of the rod is loosely fitted, and is fixed at one end to the other end wall of the housing. Since the other end portion is in sliding contact with the rotary brake, the rotary brake can slide on the fixed brake without interfering with the thread portion of the rod.
[0041]
According to the second aspect of the present invention, since the fixed braking member is a flange-shaped member that protrudes integrally from the inner surface of the peripheral wall of the housing and the other end of the rod is loosely fitted, the number of parts is reduced. be able to.
[0042]
According to the third aspect of the present invention, the rotation braking member is a cylindrical member having a bottom, and a threaded portion of the rod is screwed to the bottom, and the opening is formed at the other end of the housing. Since it comes into sliding contact with the fixed braking body provided on the wall, the number of parts can be further reduced.
[0043]
According to the fourth aspect of the present invention, the rod has a guide portion having a non-circular cross section, and the guide portion is inserted into a guide hole having a non-circular cross section formed in one end wall of the housing. Therefore, the rod can be slidably and non-rotatably supported with a simple structure.
[0044]
According to the fifth aspect of the present invention, since the pitch of the threaded portion of the rod is changed in the axial direction, the number of rotations of the rotary brake with respect to the displacement of the rod is changed to arbitrarily set the hysteresis. be able to.
[Brief description of the drawings]
FIG. 1 is an overall side view of an auto tensioner. FIG. 2 is a cross-sectional view taken along a line 2-2 in FIG. 1. FIG. 3 is a cross-sectional view taken along a line 3-3 in FIG. 1. FIG. FIG. 5 shows a diagram corresponding to FIG. 1 according to the second embodiment. FIG. 6 shows a diagram corresponding to FIG. 1 according to the third embodiment. FIG. 7 shows the diagram according to the fourth embodiment. FIG. 8 is a side view of a rod according to a fifth embodiment. FIG. 9 is a side view of a rod and a coil spring according to a sixth embodiment.
Reference Signs List 1 peripheral wall 2 end wall 2 ₁ guide hole 3 end wall 4 housing 5 rod 5 ₁ hole (elastic member receiving portion)
6 Guide part 10 Pulley (pressing member)
11 Flange part (elastic member receiving part)
12 Screw part 13 Rotation brake 14 Coil spring (elastic member)
15 Fixed braking body B Endless belt (Endless transmission belt)
F Braking means P Sliding surface

Claims

A substantially cylindrical housing (4) having a peripheral wall (1) and a pair of end walls (2, 3);
A rod (5) supported on the housing (4) so as to be movable back and forth along the axis of the housing (4) and non-rotatably;
A resilient member (14) housed inside the housing (4) and biasing the rod (5) forward from one end wall (2) of the housing (4);
A pressing member (10) supported by one end of a rod (5) extending from one end wall (2) of the housing (4) and resiliently abutting the endless transmission band (B); A) a braking means (F) housed inside to provide hysteresis between the load when the rod (5) moves forward and the load when the rod (5) moves backward;
An auto tensioner with
The braking means (F) is fixed to a housing (4) and a rotary braking body (13) which is screwed into a threaded portion (12) formed on the rod (5) and rotates by advancing and retreating of the rod (5). And a fixed brake (15) slidingly contacting the rotary brake (13). The fixed brake (15) is a cylindrical member into which the other end of the rod (5) is loosely fitted. One end is fixed to the other end wall (3) of the housing (4), and the other end is in sliding contact with the rotation brake (13), and the resilient member (14) is provided on the rod (5). It is arranged between the resilient member receiving portions (5 ₁ , 11) and the rotary brake (13) to urge the rotary brake (13) in the direction of pressing against the fixed brake (15). Features an auto tensioner.

A substantially cylindrical housing (4) having a peripheral wall (1) and a pair of end walls (2, 3);
A rod (5) supported on the housing (4) so as to be movable back and forth along the axis of the housing (4) and non-rotatably;
A resilient member (14) housed inside the housing (4) and biasing the rod (5) forward from one end wall (2) of the housing (4);
A pressing member (10) supported by one end of a rod (5) extending from one end wall (2) of the housing (4) and resiliently abutting the endless transmission band (B); A) a braking means (F) housed inside to provide hysteresis between the load when the rod (5) moves forward and the load when the rod (5) moves backward;
An auto tensioner with
The braking means (F) is fixed to a housing (4) and a rotary braking body (13) which is screwed into a threaded portion (12) formed on the rod (5) and rotates by advancing and retreating of the rod (5). And a fixed brake body (15) slidingly contacting the rotary brake body (13). The fixed brake body (15) projects integrally from the inner surface of the peripheral wall (1) of the housing (4) to form a rod (5). a flange-shaped member other end portion is loosely fitted, between the resilient member (14) is Tamahatsu member receiving portion provided in the rod (5) (5 _1, 11) and the rotating brake body (13) An auto-tensioner, which is arranged in a position to urge the rotary brake body (13) in a direction of pressing against the fixed brake body (15).

A substantially cylindrical housing (4) having a peripheral wall (1) and a pair of end walls (2, 3);
A rod (5) supported on the housing (4) so as to be movable back and forth along the axis of the housing (4) and non-rotatably;
A resilient member (14) housed inside the housing (4) and biasing the rod (5) forward from one end wall (2) of the housing (4);
A pressing member (10) supported by one end of a rod (5) extending from one end wall (2) of the housing (4) and resiliently abutting the endless transmission band (B); A) a braking means (F) housed inside to provide hysteresis between the load when the rod (5) moves forward and the load when the rod (5) moves backward;
An auto tensioner with
The braking means (F) is fixed to a housing (4) and a rotary braking body (13) which is screwed into a threaded portion (12) formed on the rod (5) and rotates by advancing and retreating of the rod (5). And a fixed brake body (15) that slides on the rotary brake body (13). The rotary brake body (13) is a cylindrical member having a bottom, and has a threaded portion of a rod (5) at the bottom thereof. (12) is screwed, and the opening thereof is in sliding contact with a fixed brake (15) provided on the other end wall (3) of the housing (4), and the resilient member (14) is connected to the rod (5). Is disposed between the resilient member receiving portions (5 ₁ , 11) and the rotary brake (13) to urge the rotary brake (13) in a direction of pressing against the fixed brake (15). An auto tensioner characterized by the following.

A substantially cylindrical housing (4) having a peripheral wall (1) and a pair of end walls (2, 3);
A rod (5) supported on the housing (4) so as to be movable back and forth along the axis of the housing (4) and non-rotatably;
A resilient member (14) housed inside the housing (4) and biasing the rod (5) forward from one end wall (2) of the housing (4);
A pressing member (10) supported by one end of a rod (5) extending from one end wall (2) of the housing (4) and resiliently abutting the endless transmission band (B); A) a braking means (F) housed inside to provide hysteresis between the load when the rod (5) moves forward and the load when the rod (5) moves backward;
An auto tensioner with
The braking means (F) is fixed to a housing (4) and a rotary braking body (13) which is screwed into a threaded portion (12) formed on the rod (5) and rotates by advancing and retreating of the rod (5). The rod (5) has a guide part (6) having a non-circular cross section, and the guide part (6) is provided with a fixed brake body (15) that slides on the rotary brake body (13). The resilient member (14) is inserted into a guide hole (2 ₁ ) having a non-circular cross section formed in one end wall (2) of the housing (4), and the resilient member (14) is provided on a resilient member receiving portion ( 5 _1, 11) and arranged between the rotating brake body (13) the auto tensioner, characterized in that biases the pressure the rotating brake body (13) to the fixed brake member (15).

A substantially cylindrical housing (4) having a peripheral wall (1) and a pair of end walls (2, 3);
A rod (5) supported on the housing (4) so as to be movable back and forth along the axis of the housing (4) and non-rotatably;
A resilient member (14) housed inside the housing (4) and biasing the rod (5) forward from one end wall (2) of the housing (4);
A pressing member (10) supported by one end of a rod (5) extending from one end wall (2) of the housing (4) and resiliently abutting the endless transmission band (B); A) a braking means (F) housed inside to provide hysteresis between the load when the rod (5) moves forward and the load when the rod (5) moves backward;
An auto tensioner with
The braking means (F) is fixed to a housing (4) and a rotary braking body (13) which is screwed into a threaded portion (12) formed on the rod (5) and rotates by advancing and retreating of the rod (5). And a fixed brake body (15) slidingly contacting the rotary brake body (13), the pitch of the threaded portion (12) of the rod (5) changes in the axial direction, and the resilient member (14) A direction in which the rotary brake (13) is disposed between the resilient member receiving portions (5 ₁ , 11) provided on the rod (5) and the rotary brake (13) to press the rotary brake (13) against the fixed brake (15). An auto-tensioner characterized in that it is biased to