JP2004324806A

JP2004324806A - Tension adjusting device of cable

Info

Publication number: JP2004324806A
Application number: JP2003122400A
Authority: JP
Inventors: Akihiko Koike; 明彦小池
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2003-04-25
Filing date: 2003-04-25
Publication date: 2004-11-18
Anticipated expiration: 2023-04-25
Also published as: JP3845387B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tension adjusting device of a cable in which a stepless tension can be adjusted, and noise is not produced on the operation. <P>SOLUTION: The tension adjusting device of the cable installed in an equalizer E is provided with an input device 15 to tow forward in order to apply a parking brake, an output transmitting member 16 engaged with the input member 15 via a first screw mechanism S1, output members 13 and 14 for regulating a forward end of the output member 16 connected to the not indicated cable, an adjusting member 17 engaged with the output transmitting member 16 via the first screw mechanism S1 and the second screw mechanism S2 of an inverse screw, a clutch mechanism 18 for restricting the rotation of the adjusting member 17, a coil spring 19 for energizing the adjusting member 17 in the backward direction and sliding the second screw mechanism S2 when the clutch mechanism 18 is engaged and released, and a coil spring 21 for applying tension to the cable by energizing the input member 15 backward with respect to the output members 13 and 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、入力部材および出力部材の少なくとも一方に接続されて牽引力を伝達するケーブルの張力を調整するケーブルの張力調整装置に関する。
【０００２】
【従来の技術】
車両のブレーキやクラッチを作動させるケーブルの伸びを調整するケーブルの張力調整装置が、下記特許文献１〜３により公知である。特許文献１には駐車ブレーキのケーブルの途中に配置されたイコライザーに張力調整装置を設けたものが記載されており、特許文献２には駐車ブレーキのブレーキレバーに張力調整装置を設けたものが記載されており、特許文献３にはクラッチやブレーキのケーブルの途中あるいは端部に張力調整装置を設けたものが記載されている。これらの張力調整装置は何れもラチェット機構を備えており、ケーブルの張力が減少したときに、ラチェット爪およびラチェット歯の係合位置を変化させてケーブルの張力を増加させるようになっている。
【０００３】
【特許文献１】
特公平４−３３６５７号公報
【特許文献２】
実公平６−２８５３号公報
【特許文献３】
特開２００１−８２４３８号公報
【０００４】
【発明が解決しようとする課題】
しかしながら上記従来の張力調整装置は何れもラチェット機構を備えているため、ラチェット爪がラチェット歯を乗り越える際に打撃音が発生する問題があるだけでなく、１回の調整量がラチェット歯のピッチに制限されてしまうため、そのピッチ未満の細かい調整できなかった。
【０００５】
本発明は前述の事情に鑑みてなされたもので、無段階の張力調整が可能であり、しかも作動時に騒音が発生しないケーブルの張力調整装置を提供することを目的とする。
【０００６】
【課題を解決するための手段】
上記目的を達成するために、請求項１に記載された発明によれば、入力部材および出力部材の少なくとも一方に接続されて牽引力を伝達するケーブルの張力を調整するケーブルの張力調整装置において、軸線方向に移動可能に配置された入力部材と、軸線方向に移動可能かつ軸線まわりに回転可能に配置されて入力部材に第１ねじ機構を介して係合する出力伝達部材と、出力伝達部材の前進端を規制する出力部材と、軸線方向に移動可能かつ軸線まわりに回転可能に配置され、第１ねじ機構と逆ねじの第２ねじ機構を介して出力伝達部材に係合するアジャスト部材と、アジャスト部材に後向きに設けた第１クラッチ面および出力部材に前向きに設けた第２クラッチ面で構成されて該アジャスト部材の軸線まわりの回転を拘束するクラッチ機構と、出力部材に対してアジャスト部材を後退方向に付勢し、クラッチ機構の第１、第２クラッチ面が離間したときに出力伝達部材に対してアジャスト部材を相対回転させる第１付勢手段と、入力部材を出力部材に対して後方に付勢してケーブルに張力を与える第２付勢手段とを備えたことを特徴とするケーブルの張力調整装置が提案される。
【０００７】
上記構成によれば、ケーブルが永久伸びした状態で、あるいはケーブルに組付時の弛みが存在する状態では出力伝達部材と出力部材との間に隙間が発生するため、入力部材を前方に牽引して該入力部材と共に出力伝達部材を前進させて前記隙間を詰めると、出力伝達部材と共にアジャスト部材が前進してクラッチ機構の第１、第２クラッチ面が離間する。その結果、第１付勢手段の付勢力で第２ねじ機構がスリップしてアジャスト部材が出力伝達部材に対して相対回転することで、アジャスト部材が後退して第１、第２クラッチ面が係合する。
【０００８】
その後に入力部材の牽引を解除すると、第２付勢手段の付勢力で出力部材に対して出力伝達部材が後方に付勢されるが、出力伝達部材に第２ねじ機構を介して係合するアジャスト部材は第１、第２クラッチ面が係合して出力部材に回転不能に拘束されているため、第２ねじ機構がスリップして出力伝達部材がアジャスト部材に対して相対回転する。すると出力伝達部材に第１ねじ機構を介して係合する入力部材が後退してケーブルの張力を増加させるが、これと同時に出力伝達部材が第２ねじ機構を介してアジャスト部材に対して後退するため、出力伝達部材に対する入力部材の後退量、即ちケーブルの永久伸び（あるいは初期弛み）の調整量は、第２付勢手段による出力伝達部材の後退量（ケーブルの永久伸び量）の全量ではなく、その一部だけに制限される。以上の過程により、入力部材が出力伝達部材に対してケーブルの永久伸び量の一部だけ後退し、これを繰り返すことによりケーブルの永久伸び量の全量が調整される。
【０００９】
このように、入力部材を一旦牽引して解放した際に第２付勢手段の付勢力で出力伝達部材が後退すると、第２ねじ機構により回転する出力伝達部材に対して入力部材が後退することでケーブルの永久伸び量が調整されるが、その調整量はケーブルの永久伸び量の一部だけであり、これを繰り返すことで最終的にケーブルの永久伸び量の全量を調整するので、入力部材に大きな負荷を加えたときにケーブルの永久伸び量の全量を超える過剰な調整が行われるのを防止することができる。
【００１０】
またラチェット機構を用いずに第１、第２ねじ機構の回転で調整を行うので、ラチェット機構に特有の打撃音が発生せずに静粛な作動が可能となるだけでなく、ラチェット機構に特有のステップ状の調整ではなく連続的な調整が可能になる。しかもケーブルの永久伸び量が大きいときには１回の調整量も大きくなるので、比較的に少ない作動回数でケーブルの永久伸び量の全量を調整することができる。
【００１１】
また請求項２に記載された発明によれば、請求項１の構成に加えて、第２ねじ機構が矩形状のねじ山およびねじ溝を有することを特徴とするケーブルの張力調整装置が提案される。
【００１２】
上記構成によれば、第２ねじ機構が矩形状のねじ山およびねじ溝を有するので、第２ねじ機構の摺動摩擦抵抗を減少させてスムーズな作動を可能にすることができる。
【００１３】
また請求項３に記載された発明によれば、請求項２の構成に加えて、第２ねじ機構が合成樹脂製あるいはアルミニウム製であることを特徴とするケーブルの張力調整装置が提案される。
【００１４】
上記構成によれば、第２ねじ機構が合成樹脂製あるいはアルミニウム製であるので、矩形状のねじ山およびねじ溝を金型成形で容易に製造することができる。
【００１５】
また請求項４に記載された発明によれば、請求項１〜請求項３の何れか１項の構成に加えて、ケーブルにより駐車ブレーキを作動させることを特徴とするケーブルの張力調整装置。
【００１６】
上記構成によれば、ケーブルの永久伸びや組付時の弛みを調整することで駐車ブレーキを確実に作動させることができる。
【００１７】
尚、実施例の支点ピン１３および円筒部材１４は本発明の出力部材に対応し、実施例のコイルスプリング１９は本発明の第１付勢手段に対応し、実施例のコイルスプリング２１は本発明の第２付勢手段に対応する。
【００１８】
【発明の実施の形態】
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。
【００１９】
図１〜図６は本発明の一実施例を示すもので、図１は駐車ブレーキ装置の全体図、図２は図１の２方向拡大斜視図、図３は図２の３−３線拡大断面図、図４は入力部材の牽引開始時の作用説明図、図５は入力部材の牽引中の作用説明図、図６は入力部材の牽引解除時の作用説明図である。
【００２０】
図１に示すように、エンジンの駆動力が自動変速機を介して伝達される左右の後輪Ｗｒ，Ｗｒにドラム式の駐車ブレーキ１，１が設けられており、運転席の横に配置された電動駐車ブレーキ装置２が左右のケーブル３，３を介して前記駐車ブレーキ１，１に接続される。各々の駐車ブレーキ１はブレーキドラム４と、ブレーキドラム４の内周面に接触可能な一対のブレーキシュー５，６と、両ブレーキシュー５，６を連結する連結ロッド７と、一方のブレーキシュー５にピン８を介して一端を回転自在に支持されたレバー９とを備えており、レバー９の他端に前記ケーブル３が接続される。
【００２１】
従って、電動駐車ブレーキ装置２に設けた電動モータ１０でケーブル３を牽引すると、レバー９がピン８まわりに図中時計方向に回転して連結ロッド７に圧縮荷重が作用し、その荷重で他方のブレーキシュー６が図中左方向に押されてブレーキドラム４に押し付けられ、かつ連結ロッド７およびピン８を介して一方のブレーキシュー５が図中右方向に押されてブレーキドラム４に押し付けられ、駐車ブレーキ１が制動力を発生する。逆に、電動モータ１０でケーブル３を緩めると、図示せぬリターンスプリングの弾発力でブレーキシュー５，６がブレーキドラム４から離反して駐車ブレーキ１の制動力が解除される。
【００２２】
電動駐車ブレーキ装置２には、２本のケーブル３，３の張力を均一化するためのイコライザーＥが設けられる。
【００２３】
次に、図２および図３に基づいてイコライザーＥの構造を説明する。尚、図３において、左側を前方と定義し、右側を後方と定義する。
【００２４】
イコライザーＥは金属板を折り曲げて形成したハウジング１１を備えており、ハウジング１１の左右両端に固定ピン１２，１２を介して固定された２本のケーブル３，３が左右の駐車ブレーキ１，１に接続される。ハウジング１１の中央に支点ピン１３を介して円筒部材１４の前端が左右揺動自在に支持される。支点ピン１３の貫通孔１３ａを緩く貫通するボルト状のロッドよりなる入力部材１５は、その前端が電動駐車ブレーキ装置２に設けた電動モータ１０（図１参照）に接続されて前方に牽引される。
【００２５】
入力部材１５の外周に形成された雄ねじに、円筒状の出力伝達部材１６の内周に形成された雌ねじが噛み合っており、これらの雄ねじおよび雌ねじは第１ねじ機構Ｓ１を構成する。第１ねじ機構Ｓ１は、概略三角形のねじ山およびねじ溝を有する一条右ねじである。出力伝達部材１６の外周に形成された雄ねじと、円筒状のアジャスト部材１７の内周に形成された雌ねじとが噛み合っており、これらの雄ねじおよび雌ねじは第２ねじ機構Ｓ２を構成する。第２ねじ機構Ｓ２は、矩形状のねじ山およびねじ溝を有する多条（実施例では３条）左ねじである。つまり、第１ねじ機構Ｓ１および第２ねじ機構Ｓ２は、そのねじ山およびねじ溝の旋回方向が逆になっている。
【００２６】
アジャスト部材１７は円筒部材１４の内部に緩く嵌合しており、アジャスト部材１７に後向きに形成した第１クラッチ面１７ａと円筒部材１４に前向きに形成した第２クラッチ面１４ａとがクラッチ機構１８を構成する。第１、第２クラッチ面１７ａ，１４ａは、入力部材１５の軸線Ｌに対してコーン状に傾斜しており、これによりクラッチ機構１８の係合力が高められる。クラッチ機構１８を係合方向に付勢すべく、支点ピン１３の座面１３ｂとアジャスト部材１７の前端との間にコイルスプリング１９およびボールベアリング２０が配置される。また出力伝達部材１６の後部に形成したフランジ１６ａと円筒部材１４との間にコイルスプリング２１およびボールベアリング２２が配置される。
【００２７】
本実施例では、入力部材１５は鉄製であり、出力伝達部材部材１６はアルミニウム製であり、アジャスト部材１７および円筒部材１４は合成樹脂製である。出力伝達部材１６およびアジャスト部材１７をアルミニウム製および合成樹脂製とすることで、第２ねじ機構Ｓ２の矩形状のねじ山およびねじ溝を容易に金型成形することができる。仮に、出力伝達部材部材１６およびアジャスト部材１７を鉄製とすると、鉄の溶融温度の関係で金型成形することができず、また切削で矩形状のねじ山およびねじ溝を製造しようとすると非常にコストが嵩んでしまう。
【００２８】
次に、上記構成を備えたイコライザーＥの作用を説明する。
【００２９】
イコライザーＥを組み付けた直後の状態、あるいはケーブル３，３に永久伸びが発生した状態では、図３に示すように、出力伝達部材１６の前端と支点ピン１３の座面１３ｂとの間に隙間αが存在する。この状態から電動駐車ブレーキ装置２を作動させて入力部材１５を前方に牽引すると、入力部材１５に第１ねじ機構Ｓ１を介して連結された出力伝達部材１６がコイルスプリング２１を圧縮しながら前記隙間αを詰め、出力伝達部材１６の前端が支点ピン１３の座面１３ｂに当接する。その結果、入力部材１５の牽引力は、出力伝達部材１６、支点ピン１３およびハウジング１１を介してケーブル３，３に伝達され、駐車ブレーキ１，１を作動させる。その際に、ハウジング１１が支点ピン１３まわりに自由に揺動することで、左右のケーブル３，３の張力を均一化して駐車ブレーキ１，１に均一な制動力を発生させることができる。
【００３０】
上述したように、前進する出力伝達部材１６がコイルスプリング２１を圧縮しながら前記隙間αを詰めると、図４に示すように、出力伝達部材１６と共に前進するアジャスト部材１７の第１クラッチ面１７ａと、円筒部材１４の第２クラッチ面１４ａとが隙間αだけ離間してクラッチ機構１８が係合解除される。すると、コイルスプリング１９の弾発力で第２ねじ機構Ｓ２がスリップすることで、図５に示すように、アジャスト部材１７が出力伝達部材１６に対して矢印Ｒ１方向に回転しながら後退し、クラッチ機構１８が再び係合する。
【００３１】
このとき、第２ねじ機構Ｓ２が摺動摩擦抵抗の小さい矩形状のねじ山およびねじ溝を有しているので、第２ねじ機構Ｓ２を容易にスリップさせてアジャスト部材１７および出力伝達部材１６をスムーズに相対回転させることができる。
【００３２】
駐車ブレーキ１，１の制動力を解除すべく入力部材１５の前方への牽引力を解除すると、図６に示すように、コイルスプリング２１の弾発力で出力伝達部材１６が後退するが、クラッチ機構１８が係合してアジャスト部材１７が円筒部材１４に移動不能かつ回転不能に拘束されているため、第２ねじ機構Ｓ２がスリップして出力伝達部材１６が回転する。その結果、出力伝達部材１６および入力部材１５が第１ねじ機構Ｓ１において相対回転し、出力伝達部材１６に対して入力部材１５が後退し、ケーブル３，３の永久伸びを補償する調整が行われる。しかしながら、これと同時にアジャスト部材１７および出力伝達部材１６が第２ねじ機構Ｓ２において相対回転することで、アジャスト部材１７に対して出力伝達部材１６が後退する。
【００３３】
この出力伝達部材１６の後退は、上述した入力部材１５の後退によるケーブル３，３の永久伸びの補償機能を一部キャンセルするように作用するため、結果としてケーブル３，３の永久伸び量の一部だけが調整される。このように、入力部材１５の牽引および解放を繰り返す度に、ケーブル３，３の永久伸び量が一部ずつ調整され、最終的にケーブル３，３の永久伸びの全量が調整されるので、入力部材１５が強い荷重で牽引された場合でも、ケーブル３，３の永久伸びの過剰な調整（オーバーアジャスト）が行われるのを防止することができる。
【００３４】
以下、上記作用を定量的に説明する。
【００３５】
入力部材１５の１回の牽引解除で該入力部材１５が出力伝達部材１６に対して後退する距離をＬｕｐとし、入力部材１５の１回の牽引解除で出力伝達部材１６がアジャスト部材１７に対して後退する距離をＬｄｎとすると、本来必要とされる調整量α（つまり前記隙間αに対応するケーブル３，３の永久伸び量）は、
α＝Ｌｕｐ＋Ｌｄｎ
で表される。
【００３６】
ここで、出力伝達部材１６の回転数をｎとし、第１ねじ機構Ｓ１のピッチをＰ１とし、第２ねじ機構Ｓ２のピッチをＰ２、条数をＮとすると、
Ｌｕｐ＝ｎＰ１
Ｌｄｎ＝ｎＮＰ２
で表される。
【００３７】
従って、入力部材１５の１回の牽引解除で調整される量の、本来必要とされる調整量Ｌに対する比率Ｒは、

で表される。
【００３８】
上式から明らかなように、前記比率Ｒは、１条ねじである第１ねじ機構Ｓ１のピッチＰ１が大きいほど、また多条ねじである第２ねじ機構Ｓ２のピッチＰ２および条数Ｎが小さいほど大きくなる。逆に、前記比率Ｒは、１条ねじである第１ねじ機構Ｓ１のピッチＰ１が小さいほど、また多条ねじである第２ねじ機構Ｓ２のピッチＰ２および条数Ｎが大きいほど小さくなる。
【００３９】
以上のように、入力部材１５を一旦牽引した後に解放すると、コイルスプリング２１の付勢力で出力伝達部材１６が後退し、第２ねじ機構Ｓ２により回転する出力伝達部材１６に対して入力部材１５が後退することでケーブル３，３の永久伸び量が調整される。このときの調整量はケーブル３，３の永久伸び量の一部だけであり、これを繰り返すことで最終的にケーブル３，３の永久伸び量の全量を調整するので、入力部材１５に大きな負荷を加えたときにケーブル３，３の永久伸び量の全量を超える過剰な調整が行われるのを防止し、従来必要であったオーバーアジャスト防止機構を廃止して構造の簡素化によるコストダウンを図ることができる。
【００４０】
またラチェット機構を用いずに第１、第２ねじ機構Ｓ１，Ｓ２の回転で調整を行うので、ラチェット機構に特有の打撃音の発生を回避することができ、しかもラチェット機構に特有のステップ状の調整を回避して連続的な調整が可能になる。またケーブル３，３の永久伸び量が大きいときには１回の調整量も大きくなるので、比較的に少ない作動回数でケーブル３，３の永久伸び量の全量を調整することができる。
【００４１】
このように、イコライザーＥに設けた張力調整装置でケーブル３，３の張力を常に最適の大きさに調整するので、駐車ブレーキ１，１の作動を確実なものにすることができる。
【００４２】
以上、本発明の実施例を説明したが、本発明はその要旨を逸脱しない範囲で種々の設計変更を行うことが可能である。
【００４３】
例えば、実施例では第１ねじ機構Ｓ１を右ねじとし、第２ねじ機構Ｓ２を左ねじとしているが、それを逆にして第１ねじ機構Ｓ１を左ねじとし、第２ねじ機構Ｓ２を右ねじとしても良い。
【００４４】
また請求項１〜請求項３の発明は、電動駐車ブレーキ装置２以外の任意の用途のケーブルに対して適用することができる。
【００４５】
また実施例では張力調整装置をイコライザーＥに設けているが、それをイコライザー以外の部位に設けることができる。
【００４６】
また実施例では張力調整装置をケーブル３の端部に設けているが、ケーブルの中間部に設けることができる。
【００４７】
【発明の効果】
以上のように請求項１に記載された発明によれば、入力部材を一旦牽引して解放した際に第２付勢手段の付勢力で出力伝達部材が後退すると、第２ねじ機構により回転する出力伝達部材に対して入力部材が後退することでケーブルの永久伸び量が調整されるが、その調整量はケーブルの永久伸び量の一部だけであり、これを繰り返すことで最終的にケーブルの永久伸び量の全量を調整するので、入力部材に大きな負荷を加えたときにケーブルの永久伸び量の全量を超える過剰な調整が行われるのを防止することができる。
【００４８】
またラチェット機構を用いずに第１、第２ねじ機構の回転で調整を行うので、ラチェット機構に特有の打撃音が発生せずに静粛な作動が可能となるだけでなく、ラチェット機構に特有のステップ状の調整ではなく連続的な調整が可能になる。しかもケーブルの永久伸び量が大きいときには１回の調整量も大きくなるので、比較的に少ない作動回数でケーブルの永久伸び量の全量を調整することができる。
【００４９】
また請求項２に記載された発明によれば、第２ねじ機構が矩形状のねじ山およびねじ溝を有するので、第２ねじ機構の摺動摩擦抵抗を減少させてスムーズな作動を可能にすることができる。
【００５０】
また請求項３に記載された発明によれば、第２ねじ機構が合成樹脂製あるいはアルミニウム製であるので、矩形状のねじ山およびねじ溝を金型成形で容易に製造することができる。
【００５１】
また請求項４に記載された発明によれば、ケーブルの永久伸びや組付時の弛みを調整することで駐車ブレーキを確実に作動させることができる。
【図面の簡単な説明】
【図１】駐車ブレーキ装置の全体図
【図２】図１の２方向拡大斜視図
【図３】図２の３−３線拡大断面図
【図４】入力部材の牽引開始時の作用説明図
【図５】入力部材の牽引中の作用説明図
【図６】入力部材の牽引解除時の作用説明図
【符号の説明】
１駐車ブレーキ
３ケーブル
１３支点ピン（出力部材）
１４円筒部材（出力部材）
１４ａ第２クラッチ面
１５入力部材
１６出力伝達部材
１７アジャスト部材
１７ａ第１クラッチ面
１８クラッチ機構
１９コイルスプリング（第１付勢手段）
２１コイルスプリング（第２付勢手段）
Ｌ軸線
Ｓ１第１ねじ機構
Ｓ２第２ねじ機構[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cable tension adjusting device that is connected to at least one of an input member and an output member and that adjusts the tension of a cable that transmits traction force.
[0002]
[Prior art]
DESCRIPTION OF RELATED ART The tension | tensile_strength adjustment apparatus of the cable which adjusts the elongation of the cable which operates the brake and clutch of a vehicle is known by the following patent documents 1-3. Patent Literature 1 describes an equalizer provided in the middle of a cable for a parking brake and provided with a tension adjusting device, and Patent Literature 2 describes a parking lever provided with a tension adjusting device on a brake lever of a parking brake. Patent Literature 3 discloses a clutch or brake cable provided with a tension adjusting device in the middle or at the end of the cable. Each of these tension adjusting devices has a ratchet mechanism, and when the tension of the cable decreases, the engagement position of the ratchet pawl and the ratchet teeth is changed to increase the tension of the cable.
[0003]
[Patent Document 1]
Japanese Patent Publication No. 4-33657 [Patent Document 2]
Japanese Utility Model Publication No. 6-2853 [Patent Document 3]
JP-A-2001-82438
[Problems to be solved by the invention]
However, since all of the above-mentioned conventional tension adjusting devices are provided with a ratchet mechanism, not only is there a problem that an impact sound is generated when the ratchet claw gets over the ratchet teeth, but also the amount of one adjustment is the pitch of the ratchet teeth. Because of the limitation, it was not possible to make fine adjustments below the pitch.
[0005]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a tension adjusting device for a cable which can adjust tension in a stepless manner and does not generate noise during operation.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a tension adjusting device for a cable, which is connected to at least one of an input member and an output member and adjusts a tension of a cable for transmitting traction force. An input member movably disposed in a direction, an output transmission member disposed axially movably and rotatably about an axis, and engaged with the input member via a first screw mechanism; An output member that regulates an end, an adjust member that is arranged to be movable in the axial direction and rotatable around the axis, and that engages with the output transmission member via a second screw mechanism of a first screw mechanism and a reverse screw; A clutch mechanism, comprising a first clutch surface provided rearward on the member and a second clutch surface provided forward on the output member, for restraining rotation of the adjustment member about an axis. First biasing means for biasing the adjusting member in the retreating direction with respect to the output member, and for relatively rotating the adjusting member with respect to the output transmitting member when the first and second clutch surfaces of the clutch mechanism are separated from each other; A second tension means for urging the input member rearward with respect to the output member to apply tension to the cable is provided.
[0007]
According to the above configuration, a gap is generated between the output transmission member and the output member in a state where the cable is permanently extended, or in a state where the cable is loose when assembled, so that the input member is pulled forward. When the output transmission member is advanced together with the input member to close the gap, the adjustment member advances together with the output transmission member, and the first and second clutch surfaces of the clutch mechanism are separated. As a result, the biasing force of the first biasing means causes the second screw mechanism to slip and the adjusting member to rotate relative to the output transmission member, whereby the adjusting member retreats and the first and second clutch surfaces are engaged. Combine.
[0008]
When the traction of the input member is subsequently released, the output transmission member is urged rearward with respect to the output member by the urging force of the second urging means, but is engaged with the output transmission member via the second screw mechanism. Since the first and second clutch surfaces engage and the output member is non-rotatably restrained by the adjust member, the second screw mechanism slips and the output transmission member rotates relative to the adjust member. Then, the input member engaged with the output transmission member via the first screw mechanism is retracted to increase the tension of the cable, but at the same time, the output transmission member is retracted relative to the adjustment member via the second screw mechanism. Therefore, the amount of retreat of the input member relative to the output transmitting member, that is, the amount of adjustment of the permanent elongation (or initial slack) of the cable is not the total amount of retreat of the output transmitting member (permanent elongation of the cable) by the second urging means. , Limited to only some of them. By the above process, the input member is retracted by a part of the permanent elongation of the cable with respect to the output transmission member, and by repeating this, the total amount of the permanent elongation of the cable is adjusted.
[0009]
As described above, when the output transmission member is retracted by the urging force of the second urging means when the input member is once pulled and released, the input member is retracted with respect to the output transmission member rotated by the second screw mechanism. The amount of permanent elongation of the cable is adjusted by, but the adjustment amount is only a part of the amount of permanent elongation of the cable, and by repeating this, the entire amount of permanent elongation of the cable is finally adjusted. When a large load is applied to the cable, excessive adjustment exceeding the total amount of permanent elongation of the cable can be prevented.
[0010]
In addition, since the adjustment is performed by rotating the first and second screw mechanisms without using the ratchet mechanism, not only the rattling mechanism does not generate a striking sound but also a quiet operation is possible, but also the ratchet mechanism is unique. A continuous adjustment is possible instead of a step-like adjustment. Moreover, when the permanent elongation of the cable is large, the amount of one adjustment is also large, so that the entire permanent elongation of the cable can be adjusted with a relatively small number of operations.
[0011]
According to the second aspect of the present invention, in addition to the configuration of the first aspect, there is proposed a tension adjusting device for a cable, wherein the second screw mechanism has a rectangular thread and a thread groove. You.
[0012]
According to the above configuration, since the second screw mechanism has the rectangular screw thread and the screw groove, the sliding friction resistance of the second screw mechanism can be reduced and smooth operation can be performed.
[0013]
According to a third aspect of the present invention, in addition to the configuration of the second aspect, there is provided a cable tension adjusting device, wherein the second screw mechanism is made of synthetic resin or aluminum.
[0014]
According to the above configuration, since the second screw mechanism is made of a synthetic resin or aluminum, a rectangular screw thread and a screw groove can be easily manufactured by die molding.
[0015]
According to a fourth aspect of the present invention, in addition to the configuration according to any one of the first to third aspects, a cable tension adjusting device that operates a parking brake by a cable.
[0016]
According to the above configuration, the parking brake can be reliably operated by adjusting the permanent elongation of the cable and the slack at the time of assembly.
[0017]
The fulcrum pin 13 and the cylindrical member 14 of the embodiment correspond to the output member of the present invention, the coil spring 19 of the embodiment corresponds to the first biasing means of the present invention, and the coil spring 21 of the embodiment corresponds to the present invention. Corresponds to the second urging means.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0019]
1 to 6 show an embodiment of the present invention. FIG. 1 is an overall view of a parking brake device, FIG. 2 is an enlarged perspective view in two directions of FIG. 1, and FIG. 3 is an enlarged view of line 3-3 in FIG. FIG. 4 is a sectional view illustrating the operation of the input member at the start of towing, FIG. 5 is a sectional view illustrating the operation of the input member during towing, and FIG.
[0020]
As shown in FIG. 1, drum-

type parking brakes

1, 1 are provided on left and right rear wheels Wr, Wr to which a driving force of an engine is transmitted via an automatic transmission, and are disposed beside a driver's seat. The electric parking brake device 2 is connected to the

parking brakes

1, 1 via left and

right cables

3, 3. Each parking brake 1 has a brake drum 4, a pair of

brake shoes

5, 6 capable of contacting the inner peripheral surface of the brake drum 4, a connecting rod 7 connecting the

brake shoes

5, 6, and one brake shoe 5. And a lever 9 rotatably supported at one end via a pin 8. The cable 3 is connected to the other end of the lever 9.
[0021]
Accordingly, when the cable 3 is pulled by the electric motor 10 provided in the electric parking brake device 2, the lever 9 rotates clockwise around the pin 8 in the drawing to apply a compressive load to the connecting rod 7, and the load causes the other load. The brake shoe 6 is pushed to the left in the drawing to be pressed against the brake drum 4, and one of the brake shoes 5 is pushed to the right in the drawing to be pressed against the brake drum 4 via the connecting rod 7 and the pin 8, The parking brake 1 generates a braking force. Conversely, when the cable 3 is loosened by the electric motor 10, the

brake shoes

5, 6 are separated from the brake drum 4 by the elastic force of a return spring (not shown), and the braking force of the parking brake 1 is released.
[0022]
The electric parking brake device 2 is provided with an equalizer E for equalizing the tension of the two cables 3.
[0023]
Next, the structure of the equalizer E will be described with reference to FIGS. In FIG. 3, the left side is defined as the front, and the right side is defined as the rear.
[0024]
The equalizer E includes a housing 11 formed by bending a metal plate. Two

cables

3, 3 fixed to the left and right ends of the housing 11 via fixing

pins

12, 12, respectively, are connected to the left and

right parking brakes

1, 1. Connected. The front end of the cylindrical member 14 is supported at the center of the housing 11 via a fulcrum pin 13 so as to be swingable right and left. The input member 15, which is a bolt-like rod that loosely penetrates the through hole 13 a of the fulcrum pin 13, has its front end connected to the electric motor 10 (see FIG. 1) provided in the electric parking brake device 2 and is pulled forward. .
[0025]
A female screw formed on the inner circumference of the cylindrical output transmission member 16 meshes with a male screw formed on the outer circumference of the input member 15, and the male screw and the female screw constitute a first screw mechanism S1. The first screw mechanism S1 is a single right-hand thread having a substantially triangular thread and a thread groove. A male screw formed on the outer periphery of the output transmission member 16 and a female screw formed on the inner periphery of the cylindrical adjusting member 17 are engaged with each other, and these male and female screws constitute a second screw mechanism S2. The second screw mechanism S2 is a multi-thread (three in this embodiment) left-hand thread having a rectangular thread and a thread groove. That is, the turning directions of the thread and the groove of the first screw mechanism S1 and the second screw mechanism S2 are reversed.
[0026]
The adjusting member 17 is loosely fitted inside the cylindrical member 14, and a first clutch surface 17a formed rearward on the adjusting member 17 and a second clutch surface 14a formed forward on the cylindrical member 14 form the clutch mechanism 18. Constitute. The first and second

clutch surfaces

17a and 14a are inclined in a cone shape with respect to the axis L of the input member 15, whereby the engagement force of the clutch mechanism 18 is increased. A coil spring 19 and a ball bearing 20 are arranged between the bearing surface 13b of the fulcrum pin 13 and the front end of the adjusting member 17 so as to urge the clutch mechanism 18 in the engagement direction. A coil spring 21 and a ball bearing 22 are arranged between the cylindrical member 14 and a flange 16a formed at a rear portion of the output transmission member 16.
[0027]
In this embodiment, the input member 15 is made of iron, the output transmission member 16 is made of aluminum, and the adjustment member 17 and the cylindrical member 14 are made of synthetic resin. Since the output transmission member 16 and the adjustment member 17 are made of aluminum or synthetic resin, the rectangular screw thread and the screw groove of the second screw mechanism S2 can be easily molded. If the output transmission member 16 and the adjustment member 17 are made of iron, it is impossible to form a mold due to the melting temperature of iron, and it is extremely difficult to manufacture rectangular threads and thread grooves by cutting. The cost increases.
[0028]
Next, the operation of the equalizer E having the above configuration will be described.
[0029]
In a state immediately after the equalizer E is assembled, or in a state in which the

cables

3 and 3 are permanently elongated, as shown in FIG. 3, a gap α is formed between the front end of the output transmission member 16 and the bearing surface 13b of the fulcrum pin 13. Exists. In this state, when the electric parking brake device 2 is operated to pull the input member 15 forward, the output transmission member 16 connected to the input member 15 via the first screw mechanism S1 compresses the coil spring 21 while the gap is compressed. The front end of the output transmission member 16 abuts on the bearing surface 13 b of the fulcrum pin 13. As a result, the traction force of the input member 15 is transmitted to the

cables

3, 3 via the output transmission member 16, the fulcrum pin 13, and the housing 11, and the

parking brake

1, 1 is operated. At this time, the housing 11 swings freely around the fulcrum pin 13, so that the tension of the left and

right cables

3, 3 is equalized, and a uniform braking force can be generated on the

parking brakes

1, 1.
[0030]
As described above, when the advancing output transmission member 16 closes the gap α while compressing the coil spring 21, as shown in FIG. 4, the first clutch surface 17 a of the adjusting member 17 advancing together with the output transmission member 16 and Then, the second clutch surface 14a of the cylindrical member 14 is separated from the second clutch surface 14a by the gap α, and the clutch mechanism 18 is disengaged. Then, the second screw mechanism S2 slips due to the elastic force of the coil spring 19, and as shown in FIG. 5, the adjusting member 17 retreats while rotating in the direction of the arrow R1 with respect to the output transmitting member 16, and the clutch moves. The mechanism 18 re-engages.
[0031]
At this time, since the second screw mechanism S2 has a rectangular screw thread and a screw groove with small sliding friction resistance, the second screw mechanism S2 is easily slipped to smoothly adjust the adjusting member 17 and the output transmission member 16. Relative rotation.
[0032]
When the forward pulling force of the input member 15 is released in order to release the braking force of the

parking brakes

1, 1, the output transmission member 16 is retracted by the elastic force of the coil spring 21 as shown in FIG. Since the adjusting member 17 is locked by the cylindrical member 14 such that the adjusting member 17 cannot move and cannot rotate, the second screw mechanism S2 slips and the output transmission member 16 rotates. As a result, the output transmission member 16 and the input member 15 rotate relative to each other in the first screw mechanism S1, the input member 15 retreats relative to the output transmission member 16, and adjustment is performed to compensate for the permanent elongation of the

cables

3 and 3. . However, at the same time, the adjustment member 17 and the output transmission member 16 are relatively rotated by the second screw mechanism S2, so that the output transmission member 16 is retracted with respect to the adjustment member 17.
[0033]
The retreat of the output transmission member 16 acts to partially cancel the function of compensating for the permanent elongation of the

cables

3 and 3 due to the retreat of the input member 15 described above. Only the parts are adjusted. As described above, each time the input member 15 is repeatedly pulled and released, the amount of permanent elongation of the

cables

3 and 3 is partially adjusted, and finally the total amount of permanent elongation of the

cables

3 and 3 is adjusted. Even when the member 15 is pulled with a strong load, it is possible to prevent the permanent elongation of the

cables

3 and 3 from being excessively adjusted (overadjusted).
[0034]
Hereinafter, the above operation will be described quantitatively.
[0035]
The distance at which the input member 15 retreats with respect to the output transmission member 16 by one release of the input member 15 is set to Lup, and the output transmission member 16 is moved relative to the adjustment member 17 by one release of the input member 15 being released. Assuming that the retreat distance is Ldn, the adjustment amount α originally required (that is, the permanent elongation amount of the cables 3 corresponding to the gap α) is
α = Lup + Ldn
Is represented by
[0036]
Here, assuming that the rotation speed of the output transmission member 16 is n, the pitch of the first screw mechanism S1 is P1, the pitch of the second screw mechanism S2 is P2, and the number of threads is N,
Lup = nP1
Ldn = nNP2
Is represented by
[0037]
Therefore, the ratio R of the amount adjusted by one release of the traction of the input member 15 to the originally required adjustment amount L is:

Is represented by
[0038]
As is clear from the above formula, the ratio R is such that the larger the pitch P1 of the first screw mechanism S1 that is a single thread, the smaller the pitch P2 and the number N of threads of the second screw mechanism S2 that are multi-threaded. It becomes bigger. Conversely, the ratio R becomes smaller as the pitch P1 of the first screw mechanism S1 that is a single-threaded screw is smaller, and as the pitch P2 and the number N of threads are larger in the second screw mechanism S2 that is a multi-threaded screw.
[0039]
As described above, when the input member 15 is once pulled and then released, the output transmission member 16 is retracted by the urging force of the coil spring 21, and the input member 15 is moved relative to the output transmission member 16 rotated by the second screw mechanism S2. By retreating, the permanent elongation of the cables 3 is adjusted. The adjustment amount at this time is only a part of the permanent elongation of the

cables

3 and 3. By repeating this, the entire permanent elongation of the

cables

3 and 3 is finally adjusted. To prevent excessive adjustment exceeding the total amount of permanent elongation of the

cables

3 and 3 when added, and eliminate the over-adjustment prevention mechanism conventionally required to reduce the cost by simplifying the structure. be able to.
[0040]
In addition, since the adjustment is performed by rotating the first and second screw mechanisms S1 and S2 without using the ratchet mechanism, it is possible to avoid the generation of a striking sound peculiar to the ratchet mechanism. Adjustment can be avoided and continuous adjustment can be performed. When the amount of permanent elongation of the

cables

3 and 3 is large, the amount of one adjustment is also large, so that the total amount of permanent elongation of the

cables

3 and 3 can be adjusted with a relatively small number of operations.
[0041]
As described above, since the tension of the

cables

3 and 3 is always adjusted to the optimum level by the tension adjusting device provided in the equalizer E, the operation of the

parking brakes

1 and 1 can be ensured.
[0042]
The embodiments of the present invention have been described above. However, various design changes can be made in the present invention without departing from the gist thereof.
[0043]
For example, in the embodiment, the first screw mechanism S1 is a right-hand screw and the second screw mechanism S2 is a left-hand screw. However, the first screw mechanism S1 is a left-hand screw, and the second screw mechanism S2 is a right-hand screw. It is good.
[0044]
Further, the inventions of claims 1 to 3 can be applied to a cable for any purpose other than the electric parking brake device 2.
[0045]
Further, in the embodiment, the tension adjusting device is provided in the equalizer E, but it can be provided in a portion other than the equalizer.
[0046]
Although the tension adjusting device is provided at the end of the cable 3 in the embodiment, it can be provided at an intermediate portion of the cable.
[0047]
【The invention's effect】
As described above, according to the first aspect of the present invention, when the input member is once pulled and released and the output transmission member is retracted by the urging force of the second urging means, the input member is rotated by the second screw mechanism. The permanent elongation of the cable is adjusted by the retreat of the input member with respect to the output transmission member, but the adjustment amount is only a part of the permanent elongation of the cable. Since the entire amount of permanent elongation is adjusted, it is possible to prevent excessive adjustment exceeding the entire amount of permanent elongation of the cable when a large load is applied to the input member.
[0048]
In addition, since the adjustment is performed by rotating the first and second screw mechanisms without using the ratchet mechanism, not only the rattling mechanism does not generate a striking sound but also a quiet operation is possible, but also the ratchet mechanism is unique. A continuous adjustment is possible instead of a step-like adjustment. Moreover, when the permanent elongation of the cable is large, the amount of one adjustment is also large, so that the entire permanent elongation of the cable can be adjusted with a relatively small number of operations.
[0049]
According to the second aspect of the present invention, since the second screw mechanism has a rectangular screw thread and a screw groove, the sliding friction resistance of the second screw mechanism is reduced to enable smooth operation. Can be.
[0050]
According to the third aspect of the present invention, since the second screw mechanism is made of synthetic resin or aluminum, a rectangular screw thread and a screw groove can be easily manufactured by die molding.
[0051]
According to the invention described in claim 4, the parking brake can be reliably operated by adjusting the permanent elongation of the cable and the slack at the time of assembly.
[Brief description of the drawings]
1 is an overall view of a parking brake device; FIG. 2 is an enlarged perspective view in two directions of FIG. 1; FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG. 2; FIG. 5 is an explanatory diagram of an operation of the input member during towing. FIG. 6 is an explanatory diagram of an operation of the input member when the torsion is released.
1 parking brake 3 cable 13 fulcrum pin (output member)
14 Cylindrical member (output member)
14a second clutch surface 15 input member 16 output transmission member 17 adjustment member 17a first clutch surface 18 clutch mechanism 19 coil spring (first biasing means)
21 coil spring (second biasing means)
L axis S1 first screw mechanism S2 second screw mechanism

Claims

In a tension adjusting device for a cable, which is connected to at least one of the input member (15) and the output member (13, 14) and adjusts the tension of a cable (3) for transmitting traction force,
An input member (15) movably arranged in the axis (L) direction,
An output transmission member (16) that is arranged to be movable in the direction of the axis (L) and rotatable about the axis (L) and engages with the input member (15) via the first screw mechanism (S1);
An output member (13) for regulating the forward end of the output transmission member (16);
It is arranged to be movable in the direction of the axis (L) and rotatable about the axis (L), and is engaged with the output transmission member (16) via the first screw mechanism (S1) and the second screw mechanism (S2) of reverse screw. An adjusting member (17) to be combined;
The axis (L) of the adjusting member (17) is constituted by a first clutch surface (17a) provided rearward on the adjusting member (17) and a second clutch surface (14a) provided forward on the output member (14). A clutch mechanism (18) for restraining the rotation around;
The adjusting member (17) is urged in the retreating direction with respect to the output member (13), and when the first and second clutch surfaces (17a, 14a) of the clutch mechanism (18) are separated, the output transmitting member (16). First biasing means (19) for relatively rotating the adjusting member (17) with respect to
Second urging means (21) for urging the input member (15) rearward against the output member (14) to apply tension to the cable (3);
A tension adjusting device for a cable, comprising:

The tension adjusting device for a cable according to claim 1, wherein the second screw mechanism (S2) has a rectangular thread and a thread groove.

The tension adjusting device for a cable according to claim 2, wherein the second screw mechanism (S2) is made of synthetic resin or aluminum.

The cable tension adjusting device according to any one of claims 1 to 3, wherein the parking brake (1) is operated by the cable (3).