JP3719663B2

JP3719663B2 - Electric disc brake

Info

Publication number: JP3719663B2
Application number: JP2002089294A
Authority: JP
Inventors: 修足立
Original assignee: Nissin Kogyo Co Ltd
Current assignee: Nissin Kogyo Co Ltd
Priority date: 2002-03-27
Filing date: 2002-03-27
Publication date: 2005-11-24
Anticipated expiration: 2022-03-27
Also published as: JP2003287065A

Abstract

<P>PROBLEM TO BE SOLVED: To prevent disconnection of the harness of a load sensor due to the advancing and retreating of the ball screw shaft by providing a load sensor detecting the load of a friction pad on the ball screw shaft of a ball screw mechanism. <P>SOLUTION: The ball screw mechanism 16 is constituted by screwing the ball screw shaft 38 generating the pressing force to the pressing member pressing friction pads 3, 4 to the ball screw nut 34 rotated by the electric motor 15. The load sensor 48 detecting the load of the friction pads 3, 4 is provided on the tip of the ball screw shaft 38. The length of the harness 50 of the load sensor 48 inserted in the hollow part 41 inside the ball screw shaft 38 is made to be more than the sum of the formed length of the hollow part 41 and the maximum moving length of the advancing and retreating of the ball screw shaft 38. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【産業上の利用分野】
本発明は、自動車や自動二輪車等の各種車両に搭載され、電動モータの駆動力でボールねじ機構のボールねじ軸を進退させ、ディスクロータに摩擦パッドを押圧摺動して制動を行う電気式ディスクブレーキに係るものであり、前記ボールねじ軸に摩擦パッドの荷重を検知する荷重センサを設け、この荷重センサのハーネスがボールねじ軸の進退時に、断線等を生じにくくするものである。
【０００２】
【従来の技術】
従来、自動車や自動二輪車等の各種車両に於いて、特開平１０−２８１１９１号公報記載の発明の如く、電動モータの駆動力でボールねじ機構を作動し、摩擦パッドの押圧部材に押圧力を発生させて制動を行うとともに、摩擦パッドに掛かる荷重を検知するための荷重センサを設けた電気式ディスクブレーキが存在する。前記ボールねじ機構は、電動モータにより回動するボールねじナットと、このボールねじナット内に進退可能に螺合するボールねじ軸とから成る。このボールねじ軸の先端に、摩擦パッドの押圧部材を接続するとともに、この接続側に前記荷重センサを配置固定している。
【０００３】
そして、この荷重センサのハーネスが、押圧部材やボールねじ軸等の進退部品間や、ボールねじナット等の回動部品間に入り込んで断線される事のないよう、本従来発明では、ボールねじ軸を中空形状に形成し、この中空部内にハーネスを挿通させ、中空部の後端からキャリパボディの外部にハーネスを突出させている。また、荷重センサとハーネスは、ボールねじ軸の進退に追随してキャリパボディ内を進退するため、この進退移動距離に対応した長さ分、余裕を設けてキャリパボディの外部にハーネスを配置している。
【０００４】
【発明が解決しようとする課題】
しかしながら、このハーネスの余裕部が、キャリパボディの外部で弛みを生じるため、車両に配置した各種部品にハーネスが絡まったり、車両の走行中に障害物に引っ掛かる等の不具合を生じる事があり、ハーネスの断線を生じ易くなるとともに、ボールねじ機構等の作動不良を生じる虞がある。
【０００５】
本発明は上述の如き課題を解決しようとするものであって、ボールねじ軸に設けた荷重センサのハーネスを、ボールねじ軸の進退移動長さに対応した余裕を持った長さとする。そして、このハーネスの余裕部を、ボールねじ軸の進退や、他の回動部品の回動の妨げにならない位置に配置して、ハーネスの断線や絡まりの防止効果を高めるとともに、ボールねじ機構及び各種回動部品の円滑な作動を可能とするものである。
【０００６】
【課題を解決するための手段】
本発明は上述の如き課題を解決するため、第１の発明は電動モータの駆動力で回動するボールねじナットと、このボールねじナット内に螺合し摩擦パッドを押圧する押圧部材に押圧力を発生させるボールねじ軸とから成るボールねじ機構と、前記ボールねじ軸の押圧部材側の先端に、摩擦パッドの荷重を検知する荷重センサを設けた電気式ディスクブレーキに於いて、前記ボールねじ軸の内部を軸方向に貫通形成して中空部を設け、この中空部に前記荷重センサのハーネスを挿通させるとともに、中空部に配置するハーネスの長さを、中空部の形成長さとボールねじ軸が進退する最大移動長さの和以上の長さとすると共に中空部に配置するハーネスは、中空部の形成長さよりも長尺とした余裕部を、伸縮可能な保持具で締結して弛み部を設けるとともに、この弛み部以外を、弛む事のないよう緊張させて成るものである。
【０００７】
また、第２の発明は、電動モータの駆動力で回動するボールねじナットと、このボールねじナット内に螺合し摩擦パッドを押圧する押圧部材に押圧力を発生させるボールねじ軸とから成るボールねじ機構と、前記ボールねじ軸の押圧部材側の先端に、摩擦パッドの荷重を検知する荷重センサを設けた電気式ディスクブレーキに於いて、前記ボールねじ軸の内部を軸方向に貫通形成して中空部を設け、この中空部に前記荷重センサのハーネスを挿通させるとともに、中空部に配置するハーネスの長さを、中空部の形成長さとボールねじ軸が進退する最大移動長さの和以上の長さとすると共に中空部に配置するハーネスは、中空部の形成長さよりも長尺とした余裕部を、軟弾性材で形成して弛み部とするとともに、この弛み部以外を、剛性材で形成するか又は剛性材で被覆して弛む事のないよう緊張させて成るものである。
【０００８】
【作用】
本発明は上述の如く構成したものであるから、運転者がブレーキペダルを踏み込んで制動操作を行うと、電動モータが駆動し、ボールねじ機構のボールねじナットが回動する。この回動によりボールねじナットに螺合したボールねじ軸が摩擦パッド方向に摺動し、摩擦パッドの押圧部材を介して摩擦パッドをディスクロータに押し付け、制動が行われる。このボールねじ軸の摺動に伴って、荷重センサも摩擦パッド方向に移動するが、荷重センサのハーネスの長さを、中空部の形成長さと前記ボールねじ軸が進退する最大移動長さの和以上の長さとして、余裕を持たせて中空部内に配置している。従って、ボールねじ軸の摺動を円滑に行う事が可能となるとともに、ハーネスの断線も生じにくいものとなる。
【０００９】
また、前記ハーネスの余裕部を中空部内に配置しているので、キャリパボディ内に於いて、中空部以外でハーネスが弛む事がなく、ボールねじナット等の回動部品へのハーネスの絡まりや引っ掛かりを生じにくくなるから、ハーネスの断線防止効果が高く、回動部品の円滑な作動も可能となる。また、本発明はハーネスの余裕を中空内に設け、従来発明の特開平１０−２８１１９１号の如く、キャリパボディの外部に弛みが形成されないから、キャリパボディ外部に於いても、絡みや引っ掛かりによるハーネスの断線が生じにくいものとなる。
【００１０】
また、上記中空部に配置するハーネスは、中空部の形成長さよりも長尺とした余裕部を、中空部にて伸縮可能な保持具で締結し、余裕部を中空部内で弛ませておけば、この弛み部以外では、ハーネスが弛む事なく緊張状態を保つ。そして、制動時にボールねじ軸が摩擦パッド方向に摺動すると、この移動距離の長さに応じて保持具が伸張するので、ハーネスの断線防止効果が高く、ボールねじ軸の摺動も円滑に行える。また、制動解除によりボールねじ軸がボールねじナット内部方向に後退すると、前記保持具が収縮して、ハーネスの緊張状態を保つので、中空部の弛み部以外でハーネスが弛む事がない。従って、進退部品や回動部品間へのハーネスの絡まりや引っ掛かりが生じにくくなり、ハーネスの断線防止効果を高める事ができる。また、前記ハーネスを締結する保持具は、伸縮可能であれば、引張り発条、ゴム材等、何れのものを使用しても良い。
【００１１】
また、中空部に配置するハーネスは、中空部の形成長さよりも長尺とした余裕部を、軟弾性材で形成して弛み部を形成可能とするとともに、この弛み部以外を、剛性材で形成するか又は剛性材で被覆して中空部内で弛む事のないよう緊張させても良い。このように形成した場合も、保持具を用いなくても、弛み部を常に中空部に配置可能となり、ボールねじ軸の進退に支障を来しにくいものとなるし、ハーネスの断線防止効果も高い。
【００１２】
【実施例】
以下、本発明の一実施例を図面に於いて説明すると、(１)は自動車の車輪に接続して一体に回動するディスクロータで、両側の摩擦面(２)に臨ませて、図１に示す如く、タイヤホイール(５)の内側に於いて、一対の摩擦パッド(３)(４)を配置している。また、前記ディスクロータ(１)に臨ませて、車両本体にブラケット(６)を固定し、この固定側からディスクロータ(１)の外周を跨いで反対側に掛けて突設したキャリパ支持腕(７)に、前記摩擦パッド(３)(４)を摺動可能に配置している。
【００１３】
また、前記ブラケット(６)のキャリパ支持腕(７)に、摩擦パッド(３)(４)をディスクロータ(１)に押し付けるキャリパボディ(８)を、図２に示す如く、一対のスライドピン(９)を介して進退可能に連結している。このキャリパボディ(８)は、図１に示す如く、ディスクロータ(１)を挟んで、一方の摩擦パッド(３)の背面に配置する作用部(１０)と、他方の摩擦パッド(４)の背面に配置する反力爪(１１)を設けた反作用部(１２)と、ディスクロータ(１)の外周を跨いで作用部(１０)及び反作用部(１２)とを連結するブリッジ部(１３)とで構成されている。
【００１４】
そして、前記作用部(１０)は、図１に示す如く、シリンダ(１４)内に、ブラシレス型の電動モータ(１５)と、摩擦パッド(３)(４)の押圧力を発生させるボールねじ機構(１６)と、このボールねじ機構(１６)に電動モータ(１５)の駆動力を減速して伝達する減速ギア機構(１７)とを収納している。この減速ギア機構(１７)は、電動モータ(１５)の駆動力により回動可能な遊星腕(１８)と、この遊星腕(１８)に回動可能に軸支した遊星歯車(２３)と、この遊星歯車(２３)を回動させる太陽歯車(２６)とから構成されている。
【００１５】
前記遊星腕(１８)は、前記電動モータ(１５)の回転子として作用するマグネット(３９)を外周に配置した円筒部(２０)と、この円筒部(２０)よりも径大で、摩擦パッド(３)とは反対側の後部に設けた径大部(２１)とから成り、電動モータ(１５)の駆動力により、軸受部(５７)を介してシリンダ(１４)内を回動可能としている。そして、径大部(２１)の外周三ヶ所に、等間隔で遊星歯車(２３)を回動可能に軸支し、図２、図３に示す如く、各遊星歯車(２３)を、径大部(２１)外周に開口した切欠窓(２２)から外部に突出させている。また、径大部(２１)は、図２に示す如く、隣接する遊星歯車(２３)間の外周を三角形状にカットして、遊星腕(１８)の軽量化を図るとともに、後述の回転角センサ(１９)のロータとしての使用を可能としている。
【００１６】
また、遊星歯車(２３)は、第１歯車部(２４)と、この第１歯車部(２４)よりも歯数の少ない第２歯車部(２５)とを、軸方向の前後に分離して一体に形成し、前記第１歯車部(２４)を、キャリパボディ(８)に回動不能に固定された太陽歯車(２６)に噛合し、この太陽歯車(２６)により遊星歯車(２３)の回動を可能としている。
【００１７】
また、上記太陽歯車(２６)の固定は、図１、図３に示す如く、キャリパボディ(８)の後部に配置したバックプレート(２７)に、等間隔で挿通穴(２９)を複数開口し、各挿通穴(２９)に挿通した固定ピン(２８)を、太陽歯車(２６)の背面に凹設した固定穴(３０)に挿入する事により行っている。前記固定ピン(２８)は、バックプレート(２７)の装着孔(３２)に装着したキャップ(３３)にて頭部を押圧され、固定穴(３０)への挿入状態が保たれている。そして、キャップ(３３)を外すと、固定ピン(２８)の頭部とバックプレート(２７)間に装着した押圧発条(３１)の付勢力により、固定ピン(２８)が固定穴(３０)から離脱し、太陽歯車(２６)の固定が解除可能となる。
【００１８】
そして、前記遊星腕(１８)内に、軸受部(５８)を介してボールねじ機構(１６)のボールねじナット(３４)を、回動可能で進退不能に収納している。このボールねじナット(３４)は、遊星腕(１８)の径大部(２１)側に配置した後端外周に、太陽歯車(２６)よりも歯数の少ない減速歯車(３５)を固定している。この減速歯車(３５)を、前記遊星歯車(２３)の第２歯車部(２５)に噛合し、遊星歯車(２３)の回動によってボールねじナット(３４)の回動を可能とし、このボールねじナット(３４)の内径側に設けたボール溝(３６)に、複数のボール(３７)を介してボールねじ軸(３８)を進退可能に螺着している。
【００１９】
また、前記ボールねじ軸(３８)は先端に、摩擦パッド(３)の押圧部材として、平板状のパッド押圧板(４０)を互いに分離不能に接続している。このパッド押圧板(４０)にて、摩擦パッド(３)を、広い面積で一部に押圧力を集中する事なく押圧して、ディスクロータ(１)に平行に押し付け可能としている。尚、上記ボールねじ軸(３８)とパッド押圧板(４０)との接続のため、図１に示す如く、ボールねじ軸(３８)は、摩擦パッド(３)側に取付ねじ(４２)を固定する固定壁(４９)を設けた中空形状に形成し、内部に中空部(４１)を設ける。また、パッド押圧板(４０)の背面に、袋穴状の取付穴(４３)を凹設する。
【００２０】
そして、ボールねじ軸(３８)の中空部(４１)側から、前記パッド押圧板(４０)の取付穴(４３)に、ボールねじ軸(３８)の固定壁(４９)を介して取付ねじ(４２)を螺着し、ボールねじ軸(３８)とパッド押圧板(４０)とを接続するものである。このような構成とする事により、パッド押圧板(４０)とボールねじ軸(３８)の接続部からのシリンダ(１４)内への塵埃や水分の侵入を防止している。また、このようにパッド押圧板(４０)とボールねじ軸(３８)との接続を、キャリパボディ(８)の後部側から行う事ができるので、組み付け性やメンテナンス性も向上するものである。また、本実施例では、パッド押圧板(４０)の外周とシリンダ(１４)の内周との間に、伸縮可能なダストシール(４７)を接続して、シリンダ(１４)の開口部(４５)を閉塞し、シリンダ(１４)内への塵埃や水分、小石等の侵入を防止可能としている。
【００２１】
また、キャリパボディ(８)には、遊星腕(１８)の回転角を検出して、ブラシレス型の電動モータ(１５)の駆動を制御したり、ボールねじ軸(３８)の進退距離を推定するための回転角センサ(１９)を設けている。この回転角センサ(１９)は、図２、図３に示す如く、シリンダ(１４)の内周面に、遊星腕(１８)の三角形状の径大部(２１)の外周に臨ませて、磁気コイルを円周状に配置してステータとし、遊星腕(１８)の径大部(２１)をロータとした構成である。この三角形状の径大部(２１)が回転角センサ(１９)の内周を回動する事により、波形の出力電圧を発生するので、遊星腕(１８)の回転角を検知可能となるものである。このように、遊星腕(１８)の径大部(２１)をロータとして兼用できるので、遊星腕(１８)とは別個に回転角センサ(１９)用のロータを設ける必要がなく、部品点数や組み付け工数の増加を防ぐ事ができる。
【００２２】
また、キャリパボディ(８)には、図１、図３に示す如く、遊星腕(１８)の径大部(２１)の後端面に臨ませて、前記バックプレート(２７)に、パーキング機構のソレノイド(５４)を設けている。そして、車両の駐車時に、摩擦パッド(３)(４)により制動を行って、ソレノイド(５４)を作動すると、係止ピン(５５)が、遊星腕(１８)の径大部(２１)端面に設けた係止穴(５６)に係合する。この係合により、遊星腕(１８)が回動不能に固定され、摩擦パッド(３)(４)による制動を維持する事ができる。また、バックプレート(２７)外周に、被覆カバー(４４)を装着して、ソレノイド(５４)やバックプレート(２７)、その他を外的衝撃から保護している。
【００２３】
また、本実施例では、前述の如く減速ギア機構(１７)を、電動モータ(１５)を介して摩擦パッド(３)(４)とは反対側に配置しているので、制動熱が減速ギア機構(１７)に伝達されにくいものとなり、減速ギア機構(１７)の高温化を防ぐ事ができる。このような制動熱の伝達による部品の高温化を防止するため、本実施例では、キャリパボディ(８)を、電動モータ(１５)の摩擦パッド(３)側と減速ギア機構(１７)側で３分割可能に形成し、各パーツ間に、図１に示す如く、キャリパボディ(８)よりも熱伝導率の低い断熱材製の断熱リング部材(４６)を挿入配置して、キャリパボディ(８)の断熱性を高めている。この断熱リング部材(４６)により、摩擦パッド(３)(４)の制動熱が、キャリパボディ(８)の外表面を介して、電動モータ(１５)、回転角センサ(１９)、ソレノイド(５４)等の電気部品、及び減速ギア機構(１７)に伝達されるのを良好に防ぐ事ができる。また、電動モータ(１５)の駆動熱が、減速ギア機構(１７)に伝達されるのも防ぐ事ができる。
【００２４】
従って、電動モータ(１５)、回転角センサ(１９)、ソレノイド(５４)等の電気部品、減速ギア機構(１７)等の高温化を良好に防ぎ、前記各部品の作動の正確性と耐久性が向上し、電気式ディスクブレーキの円滑な制動が長期に持続可能なものとなる。尚、前記断熱リング部材(４６)は、キャリパボディ(８)の本体を分割形成して、各パーツ間に挿入配置しているので、キャリパボディ(８)内部の部品に設ける場合と比較して、組み付けが容易であり、生産性に影響を与える事はない。また、分割形成によりキャリパボディ(８)の内部への各種部品の組み付け性やメンテナンス性も向上するものとなる。
【００２５】
更に、前述の如く、電動モータ(１５)をキャリパボディ(８)に内蔵し、更に前記遊星歯車(２３)等の減速ギア機構(１７)を電動モータ(１５)の内側ではなく、電動モータ(１５)よりも後部側に配置しているので、キャリパボディ(８)が長尺にも径大にもならず、コンパクトな形成が可能となる。そのため、電気式ディスクブレーキをタイヤホイール(５)の内側に設置する際のレイアウトの自由度が増すものとなる。
【００２６】
また、ボールねじ軸(３８)は、図１に示す如く、先端に荷重センサ(４８)を設けて、摩擦パッド(３)に掛かる荷重を検知可能としている。そして、本発明では、該荷重センサ(４８)と検知器本体(図示せず)とを接続するハーネス(５０)の断線防止効果を高めるため、図１に示す如く、ハーネス(５０)をボールねじ軸(３８)の中空部(４１)に挿通させている。そして、この中空部(４１)に挿通したハーネス(５０)を、ボールねじナット(３４)内に挿通させ、更に該ボールねじナット(３４)及び太陽歯車(２６)、バックプレート(２７)のキャップ(３３)の中央に各々設けた工具穴(６１)(６２)(６３)を介して、キャリパボディ(８)の外部に突出させている。尚、前記工具穴(６１)(６２)(６３)は、ボルトや工具等を挿入して各種部品の組み付けや分解等を行うためのものである。
【００２７】
そして、前記中空部(４１)の摩擦パッド(３)側の先端からキャップ(３３)の工具穴(６３)の端部までを、ハーネス(５０)の挿通間隔(６０)としている。この挿通間隔(６０)は、ボールねじ軸(３８)の進退によって、長さが伸縮するため、挿通間隔(６０)に配置するハーネス(５０)の長さに余裕を持たせる必要がある。そのため、本実施例では、ハーネス(５０)を折曲可能な軟弾性材(６５)で形成するともに、中空部(４１)に配置するハーネス(５０)の長さを、該中空部(４１)の形成長さと前記ボールねじ軸(３８)が進退する最大移動長さの和以上の長さとしている。このように、中空部(４１)にハーネス(５０)の余裕部を設ける事により、ボールねじ軸(３８)の進退を支障なく行おうとしている。
【００２８】
ところが、前記ハーネス(５０)の余裕部が中空部(４１)以外の位置で弛みを生じると、この弛みがボールねじナット(３４)とボールねじ軸(３８)間、ボールねじナット(３４)と太陽歯車(２６)間等、部品相互の隙間に入り込み、絡まりや切断を生じる虞がある。この不具合を解消するため、本実施例では、図１に示す如く、中空部(４１)内に於いて、ハーネス(５０)を引張り発条(５１)にて引張り付勢する事により、前記余裕部を弛み部(５３)として常に中空部(４１)内に配置可能としている。この引張り発条(５１)の作用により、弛み部(５３)以外では、挿通間隔(６０)内のハーネス(５０)が弛む事がなく、図１、図３に示す如く、緊張状態を保つものとなる。また、本実施例では、ハーネス(５０)の保持具として引張り発条(５１)を使用しているが、伸縮可能であれば、ゴム材等を保持具として使用しても良い。
【００２９】
また、前述の如く、ハーネス(５０)をボールねじナット(３４)の工具穴(６１)に挿通しているので、ボールねじナット(３４)の回動にハーネス(５０)が巻き込まれる虞がある。従って、図１、図３に示す如く、太陽歯車(２６)に固定したガード筒(６４)を、ボールねじナット(３４)の工具穴(６１)に挿通し、該ガード筒(６４)内にハーネス(５０)を挿通する事により、ボールねじナット(３４)の回動によるハーネス(５０)の絡まりや断線を生じにくくしている。また、図示はしないが、中空部(４１)内周にリング状のフック等を配置固定し、このフックにハーネス(５０)を進退自在に挿通すれば、中空部(４１)内でのハーネス(５０)の挿通安定性や弛み防止効果が高まるものとなる。
【００３０】
上述の如く構成された電気式ディスクブレーキでは、自動車の運転者がブレーキペダルを踏み込んで制動操作を行うと、この踏み込み量に応じて電動モータ(１５)が駆動し、遊星腕(１８)がシリンダ(１４)内を回動する。この遊星腕(１８)の回動により、径大部(２１)に軸支され、太陽歯車(２６)に第１歯車部(２４)を噛合する遊星歯車(２３)が、太陽歯車(２６)の外周を回動する。この遊星歯車(２３)の回動により、第２歯車部(２５)に減速歯車(３５)を噛合するボールねじナット(３４)が回動される。
【００３１】
そして、ボールねじ機構(１６)の作用により、回動力がボールねじ軸(３８)の摺動力に変換され、ボールねじ軸(３８)が摩擦パッド(３)(４)方向に前進し、パッド押圧板(４０)を介して作用部(１０)側の摩擦パッド(３)を押圧摺動して、ディスクロータ(１)に押し付ける。更に、ボールねじ軸(３８)の摺動の反力で、キャリパボディ(８)が後退し、反作用部(１２)の反力爪(１１)が、反作用部(１２)側の摩擦パッド(４)を押圧摺動し、ディスクロータ(１)に押し付ける事により、制動が行われる。
【００３２】
上記ボールねじ軸(３８)の摺動によって、ハーネス(５０)の挿通間隔(６０)の長さが長尺となるが、ハーネス(５０)に取り付けた引張り発条(５１)が伸張するので、ハーネス(５０)が断線しにくくなるし、ボールねじ軸(３８)の円滑な摺動が可能となる。また、上記制動の際には、前述の如く、遊星歯車(２３)は、太陽歯車(２６)と噛合する第１歯車部(２４)よりも、ボールねじナット(３４)の減速歯車(３５)と噛合する第２歯車部(２５)の歯数を少なくし、この第２歯車部(２５)にて、太陽歯車(２６)よりも歯数の少ない減速歯車(３５)を回動している。これらの作用により、電動モータ(１５)の駆動力は、効率的に減速されて、摩擦パッド(３)(４)の強い押圧力に変換可能となり、効果的な制動が可能となる。
【００３３】
そして、ブレーキペダルの踏み込みを解除すると、電動モータ(１５)の制御により遊星腕(１８)が逆回転し、遊星歯車(２３)を介してボールねじナット(３４)が、先の回転とは逆方向に回転するので、ボールねじ軸(３８)がボールねじナット(３４)内部方向に後退し、摩擦パッド(３)の押圧が解除される。また、このボールねじ軸(３８)後退の反力により、キャリパボディ(８)も復元方向に摺動し、反作用部(１２)側の摩擦パッド(４)の押圧が解除されるので、制動が解除されるものである。
【００３４】
上記ボールねじ軸(３８)の後退により、ハーネス(５０)の挿通間隔(６０)の長さが短尺となるが、引張り発条(５１)が復元収縮するので、ハーネス(５０)は、中空部(４１)内の弛み部(５３)以外の部分で弛む事はなく、緊張状態が保たれる。従って、キャリパボディ(８)の内外での、各種部品や障害物へのハーネス(５０)の絡まりや引っ掛かりが生じにくくなり、断線防止効果を高める事ができる。
【００３５】
また、上記実施例では、荷重センサ(４８)のハーネス(５０)を引張り発条(５１)やゴム材等の保持具で締結しているが、他の異なる第２実施例では、図４に示す如く、ハーネス(５０)は、中空部(４１)内に配置する余裕部を軟弾性材(６５)で形成し、余裕部以外を剛性材(６６)で形成している。この構成では、軟弾性材(６５)で形成した余裕部が中空部(４１)内で弛んで弛み部(５３)を形成可能となるとともに、挿通間隔(６０)に於いて、弛み部(５３)以外ではハーネス(５０)が弛む事がなく、緊張状態を保つ事ができる。
【００３６】
更に、他の異なる第３実施例では、図５に示す如く、ハーネス(５０)全体を軟弾性材(６５)で形成し、長尺とした余裕部を中空部(４１)に配置するとともに、余裕部以外に剛性材(６６)を溶着したり、剛性材(６６)製のパイプを装着している。このようなハーネス(５０)では、剛性材(６６)で被覆していない余裕部が、中空部(４１)内で弛んで弛み部(５３)となるとともに、弛み部(５３)以外では、剛性材(６６)により、弛む事がなく緊張状態を保つものとなる。
【００３７】
【発明の効果】
本発明は上述の如く構成したもので、ボールねじ軸を中空形状とし、この中空部に荷重センサのハーネスを挿通するとともに、中空部に配置するハーネスの長さを、中空部の形成長さと前記ボールねじ軸が進退する最大移動長さの和以上の長さとしている。このハーネスの余裕部により、ボールねじ軸の進退によるハーネスの断線防止効果が向上するとともに、ボールねじ機構の円滑な作動も可能となる。更に、ハーネスの余裕部を中空部に配置する事により、キャリパボディ内に於いてハーネスが中空部以外で弛む事がなく、ボールねじナット等のキャリパボディ内の回動部品への絡まりや引っ掛かりを防ぎ、ハーネスの断線防止効果を高める事ができる。また、キャリパボディの外部にハーネスの余裕を設ける必要もないから、キャリパボディ外部でのハーネスの断線防止効果も高まるものとなる。
【図面の簡単な説明】
【図１】本発明の第１実施例で、ディスクロータに臨ませて設置した電気式ディスクブレーキの横断面図。
【図２】図３のＡ−Ａ線断面図で、太陽歯車の固定ピンとハーネスとを省略してある。
【図３】図１のバックプレート側の部分拡大断面図。
【図４】本発明の第２実施例で、ハーネスの弛み部付近の拡大断面図。
【図５】本発明の第３実施例で、ハーネスの弛み部付近の拡大断面図。
【符号の説明】
３摩擦パッド
４摩擦パッド
１５電動モータ
１６ボールねじ機構
３４ボールねじナット
３８ボールねじ軸
４１中空部
４８荷重センサ
５０ハーネス
５３弛み部[0001]
[Industrial application fields]
The present invention is an electric disc that is mounted on various vehicles such as automobiles and motorcycles, and that makes a ball screw shaft of a ball screw mechanism advance and retreat by a driving force of an electric motor, and presses and slides a friction pad on a disc rotor to perform braking. The load sensor is provided with a load sensor for detecting the load of the friction pad on the ball screw shaft, and the harness of the load sensor is less likely to cause disconnection or the like when the ball screw shaft is advanced or retracted.
[0002]
[Prior art]
Conventionally, in various vehicles such as automobiles and motorcycles, as in the invention described in Japanese Patent Laid-Open No. 10-281191, a ball screw mechanism is operated by a driving force of an electric motor to generate a pressing force on a pressing member of a friction pad. There is an electric disc brake provided with a load sensor for performing braking and detecting a load applied to the friction pad. The ball screw mechanism includes a ball screw nut that is rotated by an electric motor, and a ball screw shaft that is threadably engaged with the ball screw nut. A friction pad pressing member is connected to the tip of the ball screw shaft, and the load sensor is disposed and fixed on the connection side.
[0003]
In order to prevent the load sensor harness from entering and disconnecting between the advancing and retreating parts such as the pressing member and the ball screw shaft, and between the rotating parts such as the ball screw nut, the present invention provides a ball screw shaft. Is formed in a hollow shape, a harness is inserted into the hollow portion, and the harness protrudes from the rear end of the hollow portion to the outside of the caliper body. In addition, the load sensor and harness move forward and backward in the caliper body following the forward and backward movement of the ball screw shaft.Therefore, a harness is arranged outside the caliper body with a margin corresponding to the length of the forward and backward movement. Yes.
[0004]
[Problems to be solved by the invention]
However, since the margin of the harness causes slack outside the caliper body, the harness may get entangled with various parts arranged on the vehicle, or it may cause problems such as being caught by an obstacle while the vehicle is running. Disconnection is likely to occur, and malfunction of the ball screw mechanism or the like may occur.
[0005]
The present invention is to solve the above-described problems, and the harness of the load sensor provided on the ball screw shaft has a length corresponding to the advance / retreat movement length of the ball screw shaft. And the margin part of this harness is arranged at a position that does not hinder the advancement / retraction of the ball screw shaft and the rotation of the other rotating parts, thereby enhancing the effect of preventing the disconnection and entanglement of the harness, and the ball screw mechanism and It enables smooth operation of various rotating parts.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a ball screw nut that is rotated by a driving force of an electric motor, and a pressing force applied to a pressing member that is screwed into the ball screw nut and presses a friction pad. In an electric disc brake provided with a ball screw mechanism comprising a ball screw shaft that generates a load and a load sensor that detects a load of a friction pad at a tip of the ball screw shaft on the pressing member side, the ball screw shaft A hollow portion is formed by penetrating the inside of the shaft in the axial direction, the harness of the load sensor is inserted into the hollow portion, and the length of the harness arranged in the hollow portion is determined by the formation length of the hollow portion and the ball screw shaft. harness disposed in the hollow portion with a maximum length of travel the length of more than the sum of the forward and backward is a slack portion is provided a margin portion which is an elongated than the formation of the hollow portion length, and fastened with expandable retainer Together, except the slack portion, those made by tension so as not to sag.
[0007]
The second invention comprises a ball screw nut that is rotated by the driving force of the electric motor, and a ball screw shaft that generates a pressing force on a pressing member that is screwed into the ball screw nut and presses the friction pad. In an electric disc brake provided with a ball screw mechanism and a load sensor for detecting the load of a friction pad at the tip of the ball screw shaft on the pressing member side, the inside of the ball screw shaft is formed to penetrate in the axial direction. The load sensor harness is inserted into the hollow portion, and the length of the harness disposed in the hollow portion is equal to or greater than the sum of the formation length of the hollow portion and the maximum moving length of the ball screw shaft to advance and retract. The harness arranged in the hollow portion and having a length longer than the formation length of the hollow portion is formed with a soft elastic material to be a slack portion, and other than the slack portion is made of a rigid material. form Either or tensed as never sag coated with rigid material are those formed by.
[0008]
[Action]
Since the present invention is configured as described above, when the driver depresses the brake pedal to perform a braking operation, the electric motor is driven and the ball screw nut of the ball screw mechanism is rotated. Due to this rotation, the ball screw shaft screwed to the ball screw nut slides in the direction of the friction pad, and the friction pad is pressed against the disc rotor via the friction pad pressing member to perform braking. As the ball screw shaft slides, the load sensor also moves in the direction of the friction pad, but the load sensor harness length is the sum of the formation length of the hollow portion and the maximum movement length of the ball screw shaft. As the above length, it has arrange | positioned in a hollow part with allowances. Therefore, the ball screw shaft can be smoothly slid and the harness is hardly broken.
[0009]
In addition, since the spare part of the harness is arranged in the hollow part, the harness does not loosen in the caliper body except in the hollow part, and the harness is entangled or caught on a rotating part such as a ball screw nut. Therefore, the effect of preventing the disconnection of the harness is high, and the rotating component can be smoothly operated. Further, according to the present invention, a harness is provided in the hollow, and no slack is formed outside the caliper body as in JP-A-10-281191 of the conventional invention. Disconnection is less likely to occur.
[0010]
In addition, the harness to be arranged in the hollow part is formed by fastening a margin part longer than the formation length of the hollow part with a holder that can be expanded and contracted in the hollow part, and loosening the margin part in the hollow part. Except for the slack portion, the harness is kept in tension without slack. When the ball screw shaft slides in the direction of the friction pad during braking, the holding tool expands according to the length of the moving distance, so that the effect of preventing the disconnection of the harness is high and the ball screw shaft can be smoothly slid. . Further, when the ball screw shaft is retracted toward the inside of the ball screw nut by releasing the brake, the retainer is contracted and the harness is kept in a tension state, so that the harness is not loosened except for the slack portion of the hollow portion. Therefore, the harness is not easily entangled or caught between the advancing / retreating parts and the rotating parts, and the effect of preventing the disconnection of the harness can be enhanced. Moreover, as long as the holder which fastens the said harness can be expanded-contracted, you may use any things, such as a tension | pulling ripening and a rubber material.
[0011]
In addition, the harness arranged in the hollow portion can be formed by forming a slack portion by forming a slack portion longer than the formation length of the hollow portion with a soft elastic material, and other than the slack portion with a rigid material. It may be formed or covered with a rigid material and tensioned so as not to loosen in the hollow part. Even when formed in this way, the slack portion can always be arranged in the hollow portion without using a holding tool, making it difficult for the ball screw shaft to move forward and backward, and the effect of preventing disconnection of the harness is also high. .
[0012]
【Example】
DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. (1) is a disk rotor that is connected to a wheel of an automobile and rotates integrally with it, facing both friction surfaces (2). As shown, a pair of friction pads (3) and (4) are arranged inside the tire wheel (5). Further, a bracket (6) is fixed to the vehicle body so as to face the disk rotor (1), and a caliper support arm (projecting from the fixed side across the outer periphery of the disk rotor (1) to the opposite side is provided. 7), the friction pads (3) and (4) are slidably disposed.
[0013]
Further, a caliper body (8) for pressing the friction pads (3), (4) against the disc rotor (1) on the caliper support arm (7) of the bracket (6), as shown in FIG. It is connected through 9) so that it can advance and retreat. As shown in FIG. 1, the caliper body (8) includes an action portion (10) disposed on the back surface of one friction pad (3) and a friction pad (4) between the disk rotor (1). A reaction portion (12) provided with a reaction force claw (11) disposed on the back surface and a bridge portion (13) for connecting the action portion (10) and the reaction portion (12) across the outer periphery of the disk rotor (1). It consists of and.
[0014]
As shown in FIG. 1, the action portion (10) has a ball screw mechanism for generating a pressing force of the brushless electric motor (15) and the friction pads (3) and (4) in the cylinder (14). (16) and a reduction gear mechanism (17) for reducing and transmitting the driving force of the electric motor (15) to the ball screw mechanism (16) are housed. The reduction gear mechanism (17) includes a planetary arm (18) that can be rotated by the driving force of the electric motor (15), a planetary gear (23) that is pivotally supported by the planetary arm (18), and The planetary gear (23) is configured to rotate with a sun gear (26).
[0015]
The planetary arm (18) includes a cylindrical portion (20) having a magnet (39) acting as a rotor of the electric motor (15) arranged on the outer periphery, a diameter larger than the cylindrical portion (20), and a friction pad. It comprises a large-diameter portion (21) provided on the rear side opposite to (3), and the inside of the cylinder (14) can be rotated via the bearing portion (57) by the driving force of the electric motor (15). Yes. Then, planetary gears (23) are pivotally supported at three positions on the outer periphery of the large-diameter portion (21) so as to be rotatable at equal intervals. As shown in FIGS. The part (21) protrudes to the outside from a notch window (22) opened on the outer periphery. Further, as shown in FIG. 2, the large-diameter portion (21) cuts the outer periphery between adjacent planetary gears (23) into a triangular shape to reduce the weight of the planetary arm (18), and the rotation angle described later. The sensor (19) can be used as a rotor.
[0016]
The planetary gear (23) separates the first gear portion (24) and the second gear portion (25) having a smaller number of teeth than the first gear portion (24) in the axial direction. The first gear portion (24) is integrally formed and meshed with a sun gear (26) fixed to the caliper body (8) so as not to rotate, and the planetary gear (23) of the planetary gear (23) is engaged with the sun gear (26). It can be turned.
[0017]
The sun gear (26) is fixed by opening a plurality of insertion holes (29) at equal intervals in the back plate (27) disposed at the rear of the caliper body (8) as shown in FIGS. The fixing pin (28) inserted into each insertion hole (29) is inserted into the fixing hole (30) recessed in the back surface of the sun gear (26). The head of the fixing pin (28) is pressed by the cap (33) mounted in the mounting hole (32) of the back plate (27), and the state of insertion into the fixing hole (30) is maintained. When the cap (33) is removed, the fixing pin (28) is removed from the fixing hole (30) by the urging force of the pressing ridge (31) mounted between the head of the fixing pin (28) and the back plate (27). The sun gear (26) can be released by releasing.
[0018]
Then, the ball screw nut (34) of the ball screw mechanism (16) is accommodated in the planetary arm (18) via a bearing portion (58) so as to be rotatable and unable to advance and retract. The ball screw nut (34) has a reduction gear (35) having fewer teeth than the sun gear (26) fixed to the outer periphery of the rear end disposed on the large diameter portion (21) side of the planetary arm (18). Yes. The reduction gear (35) meshes with the second gear portion (25) of the planetary gear (23), and the rotation of the planetary gear (23) enables the ball screw nut (34) to rotate. A ball screw shaft (38) is threadably attached to a ball groove (36) provided on the inner diameter side of the screw nut (34) via a plurality of balls (37).
[0019]
The ball screw shaft (38) has a flat pad pressing plate (40) as a pressing member for the friction pad (3) connected to the tip of the ball screw shaft (38) so as not to be separated from each other. With this pad pressing plate (40), the friction pad (3) can be pressed in a large area without concentrating the pressing force on a part thereof, and can be pressed in parallel with the disk rotor (1). In order to connect the ball screw shaft (38) and the pad pressing plate (40), as shown in FIG. 1, the ball screw shaft (38) has a mounting screw (42) fixed to the friction pad (3) side. It forms in the hollow shape which provided the fixed wall (49) to perform, and provides a hollow part (41) inside. Further, a bag-hole-like mounting hole (43) is recessed in the back surface of the pad pressing plate (40).
[0020]
Then, from the hollow portion (41) side of the ball screw shaft (38) to the mounting hole (43) of the pad pressing plate (40) through the fixing wall (49) of the ball screw shaft (38), 42), and the ball screw shaft (38) and the pad pressing plate (40) are connected. By adopting such a configuration, the entry of dust and moisture into the cylinder (14) from the connecting portion between the pad pressing plate (40) and the ball screw shaft (38) is prevented. Further, since the pad pressing plate (40) and the ball screw shaft (38) can be connected from the rear side of the caliper body (8) as described above, the assembling property and the maintenance property are improved. Further, in this embodiment, an expandable / contractible dust seal (47) is connected between the outer periphery of the pad pressing plate (40) and the inner periphery of the cylinder (14), and the opening (45) of the cylinder (14). To prevent the entry of dust, moisture, pebbles, etc. into the cylinder (14).
[0021]
The caliper body (8) detects the rotation angle of the planetary arm (18) to control the drive of the brushless type electric motor (15), and estimates the advance / retreat distance of the ball screw shaft (38). A rotation angle sensor (19) is provided. As shown in FIGS. 2 and 3, the rotation angle sensor (19) faces the outer periphery of the large-diameter portion (21) of the triangular shape of the planetary arm (18) on the inner peripheral surface of the cylinder (14). A magnetic coil is arranged circumferentially to form a stator, and the large-diameter portion (21) of the planetary arm (18) is a rotor. The triangular large diameter portion (21) rotates the inner circumference of the rotation angle sensor (19) to generate a waveform output voltage, so that the rotation angle of the planetary arm (18) can be detected. It is. Thus, since the large diameter part (21) of the planetary arm (18) can be used as a rotor, it is not necessary to provide a rotor for the rotation angle sensor (19) separately from the planetary arm (18). Increase in assembly man-hours can be prevented.
[0022]
Further, as shown in FIGS. 1 and 3, the caliper body (8) faces the rear end surface of the large diameter portion (21) of the planetary arm (18), and the back plate (27) has a parking mechanism. A solenoid (54) is provided. Then, when the vehicle is parked, braking is performed by the friction pads (3) and (4) and the solenoid (54) is operated, so that the locking pin (55) is the end surface of the large diameter portion (21) of the planetary arm (18). It engages with a locking hole (56) provided in. By this engagement, the planetary arm (18) is fixed so as not to rotate, and braking by the friction pads (3) and (4) can be maintained. A covering cover (44) is attached to the outer periphery of the back plate (27) to protect the solenoid (54), the back plate (27), and others from external impacts.
[0023]
In this embodiment, as described above, the reduction gear mechanism (17) is disposed on the opposite side of the friction pads (3) and (4) via the electric motor (15), so that the braking heat is reduced by the reduction gear. It becomes difficult to be transmitted to the mechanism (17), and the high temperature of the reduction gear mechanism (17) can be prevented. In order to prevent such a high temperature of the parts due to the transmission of braking heat, in this embodiment, the caliper body (8) is mounted on the friction pad (3) side and the reduction gear mechanism (17) side of the electric motor (15). As shown in FIG. 1, a heat insulating ring member (46) made of a heat insulating material having a lower thermal conductivity than that of the caliper body (8) is inserted and arranged between the parts, and the caliper body (8 ) Is improved. Due to the heat insulating ring member (46), the braking heat of the friction pads (3) and (4) is transmitted through the outer surface of the caliper body (8) to the electric motor (15), the rotation angle sensor (19), the solenoid (54 ) And the like and transmission to the reduction gear mechanism (17) can be satisfactorily prevented. Further, it is possible to prevent the drive heat of the electric motor (15) from being transmitted to the reduction gear mechanism (17).
[0024]
Therefore, it is possible to satisfactorily prevent high temperatures of the electric parts such as the electric motor (15), the rotation angle sensor (19), the solenoid (54), the reduction gear mechanism (17), etc., and the accuracy and durability of the operation of each part. As a result, smooth braking of electric disc brakes will be sustainable over the long term. In addition, since the said heat insulation ring member (46) has divided and formed the main body of the caliper body (8) and is arranged between each part, compared with the case where it is provided in the components inside the caliper body (8). Assembling is easy and productivity is not affected. Moreover, the assembling property and the maintenance property of various parts inside the caliper body (8) are also improved by the divided formation.
[0025]
Further, as described above, the electric motor (15) is built in the caliper body (8), and the reduction gear mechanism (17) such as the planetary gear (23) is not located inside the electric motor (15) but on the electric motor ( Since the caliper body (8) is neither long nor large in diameter, it can be formed in a compact form. Therefore, the degree of freedom in layout when the electric disc brake is installed inside the tire wheel (5) is increased.
[0026]
Further, as shown in FIG. 1, the ball screw shaft (38) is provided with a load sensor (48) at its tip so that the load applied to the friction pad (3) can be detected. In the present invention, in order to enhance the effect of preventing disconnection of the harness (50) connecting the load sensor (48) and the detector main body (not shown), the harness (50) is connected to a ball screw as shown in FIG. The shaft (38) is inserted through the hollow portion (41). Then, the harness (50) inserted through the hollow portion (41) is inserted into the ball screw nut (34), and the ball screw nut (34), the sun gear (26), and the cap of the back plate (27). It protrudes to the outside of the caliper body (8) through tool holes (61), (62) and (63) provided at the center of (33). The tool holes (61), (62) and (63) are for inserting bolts, tools and the like to assemble and disassemble various parts.
[0027]
The distance from the tip of the hollow portion (41) on the friction pad (3) side to the end of the tool hole (63) of the cap (33) is defined as the insertion interval (60) of the harness (50). Since the length of the insertion interval (60) expands and contracts as the ball screw shaft (38) advances and retracts, it is necessary to provide a margin for the length of the harness (50) disposed at the insertion interval (60). Therefore, in this embodiment, the harness (50) is formed of a bendable soft elastic material (65), and the length of the harness (50) disposed in the hollow portion (41) is set to the length of the hollow portion (41). And a length greater than or equal to the sum of the maximum length of movement of the ball screw shaft (38). In this way, by providing the hollow portion (41) with the extra portion of the harness (50), the ball screw shaft (38) can be advanced and retracted without hindrance.
[0028]
However, when the slack portion of the harness (50) is loosened at a position other than the hollow portion (41), the slack is caused between the ball screw nut (34) and the ball screw shaft (38) and between the ball screw nut (34). There is a risk of entanglement or cutting by entering the gaps between components such as between the sun gears (26). In order to eliminate this problem, in the present embodiment, as shown in FIG. 1, the harness (50) is tensioned and urged by the tension ridge (51) in the hollow portion (41), thereby the margin portion. Can be always disposed in the hollow portion (41) as a slack portion (53). By the action of the tension ridge (51), the harness (50) in the insertion interval (60) is not loosened except for the slack portion (53), and the tensioned state is maintained as shown in FIGS. Become. Further, in this embodiment, the pulling ridge (51) is used as a holder for the harness (50). However, a rubber material or the like may be used as the holder as long as it can be expanded and contracted.
[0029]
Further, as described above, since the harness (50) is inserted into the tool hole (61) of the ball screw nut (34), there is a possibility that the harness (50) is caught by the rotation of the ball screw nut (34). . Accordingly, as shown in FIGS. 1 and 3, the guard cylinder (64) fixed to the sun gear (26) is inserted into the tool hole (61) of the ball screw nut (34), and is inserted into the guard cylinder (64). By inserting the harness (50), the harness (50) is less likely to be entangled or disconnected due to the rotation of the ball screw nut (34). Although not shown, if a ring-shaped hook or the like is arranged and fixed on the inner periphery of the hollow portion (41) and the harness (50) is inserted into the hook so as to be able to advance and retreat, the harness in the hollow portion (41) ( 50) The insertion stability and slack prevention effect of 50) are enhanced.
[0030]
In the electric disc brake configured as described above, when the driver of the automobile depresses the brake pedal and performs a braking operation, the electric motor (15) is driven according to the amount of depression, and the planetary arm (18) is (14) Turn inside. Due to the rotation of the planetary arm (18), the planetary gear (23) that is pivotally supported by the large-diameter portion (21) and meshes with the first gear portion (24) in the sun gear (26) is the sun gear (26). Rotate the outer periphery of the. The rotation of the planetary gear (23) rotates the ball screw nut (34) that meshes with the reduction gear (35) in the second gear portion (25).
[0031]
Then, by the action of the ball screw mechanism (16), the turning force is converted into the sliding force of the ball screw shaft (38), the ball screw shaft (38) advances in the direction of the friction pad (3) (4), and the pad press The friction pad (3) on the acting part (10) side is pressed and slid through the plate (40) and pressed against the disk rotor (1). Further, the caliper body (8) is retracted by the sliding reaction force of the ball screw shaft (38), and the reaction force claw (11) of the reaction portion (12) is moved to the friction pad (4) on the reaction portion (12) side. ) Is pressed and slid and pressed against the disc rotor (1) to perform braking.
[0032]
By sliding the ball screw shaft (38), the length of the insertion interval (60) of the harness (50) becomes long, but the tension ridge (51) attached to the harness (50) extends, so the harness (50) is difficult to break, and the ball screw shaft (38) can be smoothly slid. During the braking, the planetary gear (23) has a reduction gear (35) of the ball screw nut (34) rather than the first gear portion (24) meshing with the sun gear (26) as described above. The number of teeth of the second gear portion (25) meshing with the gear is reduced, and the reduction gear (35) having a smaller number of teeth than the sun gear (26) is rotated by the second gear portion (25). . By these actions, the driving force of the electric motor (15) is efficiently decelerated and can be converted into a strong pressing force of the friction pads (3) and (4), so that effective braking is possible.
[0033]
When the depression of the brake pedal is released, the planetary arm (18) rotates reversely under the control of the electric motor (15), and the ball screw nut (34) is reversely rotated through the planetary gear (23). Therefore, the ball screw shaft (38) retreats toward the inside of the ball screw nut (34), and the pressing of the friction pad (3) is released. Further, the caliper body (8) slides in the restoring direction by the reaction force of the retraction of the ball screw shaft (38), and the pressing of the friction pad (4) on the reaction portion (12) side is released, so that braking is performed. It is to be canceled.
[0034]
With the retraction of the ball screw shaft (38), the length of the insertion interval (60) of the harness (50) becomes short, but the tension ridge (51) is restored and contracted, so that the harness (50) has a hollow portion ( 41) The portion other than the slack portion (53) in the portion 41) does not loosen, and the tensioned state is maintained. Therefore, the harness (50) is not easily entangled and caught on various parts and obstacles inside and outside the caliper body (8), and the effect of preventing disconnection can be enhanced.
[0035]
Moreover, in the said Example, although the harness (50) of the load sensor (48) is fastened with holders, such as a tension | pulling ridge (51) and a rubber material, in another different 2nd Example, it shows in FIG. As described above, in the harness (50), the margin portion disposed in the hollow portion (41) is formed of the soft elastic material (65), and the other portion is formed of the rigid material (66). In this configuration, the margin portion formed of the soft elastic material (65) can be loosened in the hollow portion (41) to form the slack portion (53), and the slack portion (53) can be formed at the insertion interval (60). Other than), the harness (50) does not loosen and can maintain a tension state.
[0036]
Furthermore, in another different 3rd Example, as shown in FIG. 5, while forming the harness (50) whole with a soft elastic material (65) and arrange | positioning the elongate margin part in the hollow part (41), A rigid material (66) is welded or a pipe made of the rigid material (66) is attached in addition to the margin. In such a harness (50), the margin part not covered with the rigid material (66) is loosened in the hollow part (41) to become a slack part (53). The material (66) keeps the tension state without loosening.
[0037]
【The invention's effect】
The present invention is configured as described above, and the ball screw shaft has a hollow shape, and the harness of the load sensor is inserted into the hollow portion, and the length of the harness disposed in the hollow portion is defined as the formation length of the hollow portion. The length is equal to or greater than the sum of the maximum moving lengths of the ball screw shaft. The margin portion of the harness improves the effect of preventing the disconnection of the harness due to the advancement / retraction of the ball screw shaft, and also enables a smooth operation of the ball screw mechanism. Furthermore, by arranging the extra part of the harness in the hollow part, the harness does not loosen in the caliper body except in the hollow part, and entanglement and catching on rotating parts in the caliper body such as ball screw nuts can be prevented. This can prevent the disconnection of the harness and enhance the effect. Further, since it is not necessary to provide a harness margin outside the caliper body, the effect of preventing the harness from being disconnected outside the caliper body is also enhanced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an electric disc brake installed to face a disc rotor in a first embodiment of the present invention.
2 is a cross-sectional view taken along the line AA in FIG. 3, and a fixing pin and a harness of the sun gear are omitted.
3 is a partially enlarged cross-sectional view of the back plate side of FIG. 1;
FIG. 4 is an enlarged sectional view of the vicinity of a slack portion of a harness in a second embodiment of the present invention.
FIG. 5 is an enlarged sectional view of the vicinity of a slack portion of a harness in a third embodiment of the present invention.
[Explanation of symbols]
3 Friction pad 4 Friction pad 15 Electric motor 16 Ball screw mechanism 34 Ball screw nut 38 Ball screw shaft 41 Hollow portion 48 Load sensor 50 Harness 53 Loose portion

Claims

A ball screw mechanism comprising: a ball screw nut that is rotated by a driving force of an electric motor; and a ball screw shaft that engages in the ball screw nut and presses a friction pad to generate a pressing force; In an electric disc brake provided with a load sensor for detecting the load of a friction pad at the tip of the pressing member side of the shaft, a hollow portion is formed by penetrating the inside of the ball screw shaft in the axial direction. with inserting the harness of the load sensor section, the length of the harness disposed in the hollow portion, the hollow portion with the formation of the hollow portion length and the ball screw shaft is the maximum length of travel the length of more than the sum of the forward and backward The harness to be arranged is provided with a slack portion by fastening a margin portion longer than the formation length of the hollow portion with an extendable holder, and tension other than the slack portion so as not to loosen. Electric disc brake, characterized in that was.

A ball screw mechanism comprising: a ball screw nut that is rotated by a driving force of an electric motor; and a ball screw shaft that engages in the ball screw nut and presses a friction pad to generate a pressing force; In an electric disc brake provided with a load sensor for detecting the load of a friction pad at the tip of the pressing member side of the shaft, a hollow portion is formed by penetrating the inside of the ball screw shaft in the axial direction. The harness of the load sensor is inserted into the part, and the length of the harness arranged in the hollow part is set to be equal to or longer than the sum of the formation length of the hollow part and the maximum movement length of the ball screw shaft to advance and retract. In the harness to be arranged, a margin part longer than the formation length of the hollow part is formed with a soft elastic material to be a slack part, and other than the slack part is formed with a rigid material or with a rigid material. Electric disc brake, characterized in that was tense so as not to be loosened overturned.