JP3750933B2

JP3750933B2 - Electric disc brake layout

Info

Publication number: JP3750933B2
Application number: JP2002045737A
Authority: JP
Inventors: 修足立
Original assignee: Nissin Kogyo Co Ltd
Current assignee: Nissin Kogyo Co Ltd
Priority date: 2002-02-22
Filing date: 2002-02-22
Publication date: 2006-03-01
Anticipated expiration: 2022-02-22
Also published as: JP2003247576A

Abstract

<P>PROBLEM TO BE SOLVED: To provide a product to prevent increase of temperature of a reduction gear mechanism for reducing drive force of an electric motor due to brake heat of a friction pad, improve operating properties and durability with excellent assembling properties, productivity, and maintainability, and compact caliper body, and improve degree of freedom of layout during situation of an electric display brake at a vehicle. <P>SOLUTION: A forward and backward moving mechanism is provided to be moved forward and backward by the drive force of the electric motor 15, and the electric disc brake causes pressing and sliding of press members of friction pads 3 and 4 to generate a press force. The electric disc brake is provided such that braking is performed by pressing and sliding friction pads 3 and 4 against a disc rotor 1. The electric motor 15 is situated between the friction pads 3 and 4 and a reduction gear mechanism 17 to reduce the drive force of the electric motor 15, and to transmit it to the forward and backward moving mechanism. <P>COPYRIGHT: (C)2003,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進退作動機構を進退させ、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の配置構造に係るものであり、電動モータの駆動力を減速して進退作動機構に伝達する減速ギア機構を、摩擦パッドから離れた位置に配置し、制動熱による減速ギア機構の高温化を防止して、減速ギア機構の作動の正確性と耐久性を向上させようとするものである。
【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、電動モータの駆動力によりボールネジ等の進退作動機構を進退させ、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が存在する。そして、電動モータの駆動力を減速して、進退作動機構に伝達する減速ギア機構として、特表平１０−５０４８７６号、特表平３−５００９２０号、特表２００１−５２４６４７号公報記載発明の如く、遊星歯車を用いたものが存在し、電動モータの駆動力を効率的に減速して、摩擦パッドに強い押圧力を発生させる事が可能であった。
【０００３】
【発明が解決しようとする課題】
しかしながら、上記特表平１０−５０４８７６号、特表平３−５００９２０号公報記載の従来発明では、電動モータと摩擦パッドとの間に、遊星歯車等のギア部品を配置しているので、摩擦パッドとディスクロータ間で発生する制動熱や電動モータの熱が、キャリパボディの表面を介して、又は雰囲気熱として伝達され易く、放熱性も悪いため、前記ギア部品の高温化を生じ易かった。この高温化により、ギア部品が熱膨張して作動不良を生じたり、ギア部品を潤滑するグリス等の油脂の劣化を招いていた。
【０００４】
上記熱膨張による作動不良を防ぐためには、キャリパボディの内部に於いて、摩擦パッドと減速ギア機構との間に断熱材を配置する等の断熱対策が必要となり、組み付け性の悪化や部品点数の増加を生じ、生産性やメンテナンス性が低下する虞がある。また、グリスの劣化を防止するには、耐高温性のグリスの使用等が必要となり、コスト高となる。
【０００５】
また、特表２００１−５２４６４７号公報記載発明では、電動モータの内側に、複数段の歯車を噛み合わせて、減速ギア機構を構成し、摩擦パッドとの距離を大きくしているので、他の従来技術に比べて、減速ギア機構に制動熱が伝わりにくい。しかしながら、キャリパボディの作用部側が、径方向に大きく形成されるため、ドライブシャフト等が突出する狭いタイヤホイールの内側に製品を設置する際に、レイアウト上の制約を受け易い。また、特表平３−５００９２０号の従来発明では、電動モータを内蔵せず、キャリパボディの後部に別個に配置しているので、径大とはならないがキャリパボディがディスク軸の方向に長尺に形成され、この製品の設置の際も、レイアウト上の制約を受ける可能性がある。
【０００６】
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、減速ギア機構を、摩擦パッドの制動熱の影響を受けにくい位置に配置可能とするものである。そして、減速ギア機構の高温化を防止して耐久性を向上させ、円滑で正確な作動を持続可能とする。また、ギア部品に使用するグリスの劣化を防止し、部品点数の増加を防ぎ、組み付け性、メンテナンス性に優れた低コストな製品を得るものである。また、キャリパボディの径大化を防ぎ、コンパクトな製品を得て、車両への設置時のレイアウトの自由度を高めようとするものである。
【０００７】
【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、電動モータの駆動力が伝達されて回動するボールねじナットの回転運動をボールねじ軸の進退運動に変換する事によって、該ボールねじ軸で摩擦パッドの押圧部材に押圧力を発生させる進退作動機構をキャリパボディに設け、この進退作動機構によりディスクロータに摩擦パッドを押圧摺動させて制動を行う電気式ディスクブレーキに於いて、前記電動モータが、前記の進退作動機構を内周側に収容し、外周にマグネットを配置した円筒状の円筒部を回動させ、該円筒部の回動力を減速して前記進退作動機構のボールねじ軸に伝達する減速ギア機構を備え、前記電動モータを、前記摩擦パッドと減速ギア機構との間に配置するとともに、この減速ギア機構は、前記電動モータの前記円筒部と一体に回動し摩擦パットとは反対側の後部に円筒部よりも径大な径大部を設けた遊星腕と、この径大部の外周に回動可能に軸支されるとともに径大部の外周に開口した切欠窓から外部に突出させた遊星歯車と、前記キャリパボディに回動不能に固定され、前記遊星歯車と噛合することで該遊星歯車を回動させる太陽歯車と、前記遊星歯車と噛合することで前記進退作動機構のボールねじナットと一体に回動する減速歯車とを備えた遊星歯車減速機構としてなるものである。
【０００８】
また、前記進退作動機構は、遊星歯車に第１歯車部と、この第１歯車部よりも歯数の少ない第２歯車部とを、軸方向の前後に分離して一体に形成し、前記第１歯車部を、キャリパボディに回動不能に固定された太陽歯車に噛合し、前記第２歯車部を前記減速歯車に噛合するとともに前記遊星歯車よりも径大で遊星歯車の回動によって回動するボールねじナットと、このボールねじナットの回動により、ディスク軸の方向に進退するボールねじ軸とから成り、遊星歯車にて径大なボールねじナットを回動する事により、減速ギア機構から伝達される回動力を更に減速して、ボールねじ軸を介して押圧部材に押圧力を発生させるものであっても良い。
【０００９】
【作用】
本発明は上述の如く構成したものであり、電動式ディスクブレーキの電動モータを、摩擦パッドと減速ギア機構との間に配置する事により、摩擦パッドから離れた位置に減速ギア機構を配置可能となり、ギア部品の制動熱からの影響を減らす事ができる。また、このような減速ギア機構の位置では、放熱性が向上し、適宜の冷却手段での冷却も行い易いものとなる。
【００１０】
従って、減速ギア機構の高温化を良好に防止可能で、ギア部品の熱膨張による作動不良やグリスの劣化等を防止して、減速ギア機構の作動の正確性と耐久性を向上させる事ができる。また、厳密な断熱対策等を必要とせず、部品点数や製造工程の増加を防ぎ、生産性や組み付け性を向上させ、低コストな製品を得る事ができる。更に、キャリパボディの分解や再組み付けも容易となり、車両使用時のメンテナンス性も向上する。また、キャリパボディが径大とならず、タイヤホイールの内側への電気式ディスクブレーキ設置時の、レイアウトの自由度が増すものとなる。
【００１１】
また、減速ギア機構は、摩擦パッドとの間に電動モータを介在する構造であれば、従来公知の何れの機構を用いても良く、例えば電動モータにより回動可能な遊星腕と、この遊星腕の外周に回動可能に軸支される遊星歯車と、キャリパボディに回動不能に固定され、前記遊星歯車を回動させる太陽歯車とから成る遊星歯車機構であっても良い。
【００１２】
この遊星歯車機構の作用により、電動モータの駆動力が効率的に減速されて、ボールねじ軸による摩擦パッドの強い押圧力に変換され、良好な制動が行われるものである。また、遊星歯車機構を用いる事により、キャリパボディが径大とならないだけでなく、ディスク軸の方向にも長尺とはならず、電気式ディスクブレーキ装置全体をコンパクトに形成でき、車両への設置時のレイアウトの自由度が、更に向上するものとなる。
【００１３】
また、前記進退作動機構は、従来公知の何れの機構であっても良く、例えば前記減速機構の遊星歯車よりも径大で遊星歯車の回動によって回動するボールねじナットと、このボールねじナットの回動により、ディスク軸の方向に進退するボールねじ軸とから成るボールねじ機構を用いる事ができる。そして、遊星歯車にて径大なボールねじナットを回動する事により、減速ギア機構により減速された電動モータの駆動力が、更に減速されるので、電動モータの駆動力をボールねじ軸の進退力に効率的に変換して、押圧部材に強い押圧力を発生させる事ができる。
【００１４】
【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)は自動車の駆動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、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。
【００１５】
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)に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。
【００１６】
そして、前記作用部(１０)は、図１に示す如く、シリンダ(１４)内に、電動モータ(１５)と、摩擦パッド(３)(４)の押圧力を発生させる進退作動機構としてのボールねじ機構(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。
【００１７】
前記遊星腕(１８)は、外周にマグネット(３９)を配置した円筒状の円筒部(２０)と、摩擦パッド(３)とは反対側の後部に設け、円筒部(２０)よりも径大な径大部(２１)とから成り、円筒部(２０)のマグネット(３９)の外周に配置した電動モータ(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３〜図５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、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。
【００１８】
また、遊星歯車(２３)は、図１、図３に示す如く、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。
【００１９】
また、上記太陽歯車(２６)の固定は、図１、図３、図６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。
【００２０】
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)の回動を可能としている。
【００２１】
また、ボールねじナット(３４)の中央にボール溝(３６)を設け、図１、図６、図７に示す如く、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。このボールねじ軸(３８)は先端に、図１に示す如く、一方の摩擦パッド(３)の押圧部材として、平板状のパッド押圧板(４０)を接続している。このパッド押圧板(４０)にて、前記摩擦パッド(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。また、本実施例では、パッド押圧板(４０)の外周とシリンダ(１４)の内周間に、伸縮可能なダストシール(４７)を接続し、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。
【００２２】
尚、上記ボールねじ軸(３８)とパッド押圧板(４０)との接続は、図１に示す如く、ボールねじ軸(３８)の内部を貫通形成して中空部(４１)を設け、この中空部(４１)内から、パッド押圧板(４０)の背面に凹設した袋穴状の取付穴(４３)に、取付ねじ(４２)を螺着して行うものである。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も防止している。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。
【００２３】
上述の如く構成する事により、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)とは反対側の後部側に配置可能となる。そのため、特表平１０−５０４８７６号、特表平３−５００９２０号等の従来技術の如く、ギア部品を摩擦パッドと電動モータとの間に配置した場合に比べて、本発明のキャリパボディ(８)では、前記ギア部品への制動熱の伝達を抑える事ができる。
【００２４】
また、この制動熱及び電動モータ(１５)の回動熱が、キャリパボディ(８)表面や内部空間を介して伝達されても、太陽歯車(２６)、遊星歯車(２３)、減速歯車(３５)を、キャリパボディ(８)の後部側に配置しているので、内部に設けた場合に比べて放熱性に優れ、適宜の冷却手段での冷却も容易となる。従って、減速ギア機構(１７)の高温化の防止効果が高く、熱膨張による作動不良やグリスの劣化等を防止して、減速ギア機構(１７)の作動の正確性と耐久性を向上させる事ができる。
【００２５】
また、従来技術の特表２００１−５２４６４７号では、電動モータの内部に減速ギア機構を組み込んでいたので、キャリパボディの径大化を招き、特表平３−５００９２０号では、電動モータをキャリパボディの後部に別個に配置しているので、ディスク軸の方向に長尺な製品となり、共に設置の際にレイアウト上の制限を受けていた。これに対して、本実施例では、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)よりも後部側に配置している。従って、キャリパボディ(８)が長尺にも径大にもならず、コンパクト化が可能となり、レイアウトの自由度が増すものとなる。
【００２６】
また、本実施例では、減速ギア機構(１７)への断熱効果を更に高めるため、キャリパボディ(８)は、電動モータ(１５)の前後で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リング状の断熱部材(４６)を挿入配置している。この断熱部材(４６)により、キャリパボディ(８)の表面を介して、摩擦パッド(３)(４)の制動熱や、電動モータ(１５)の回動熱がギア部品に伝達されるのを防止して、減速ギア機構(１７)の高温化の防止効果を更に高める事ができる。また、電動モータ(１５)への制動熱の伝達も防止するので、電動モータ(１５)の高温化による作動不良も防止する事ができる。また、断熱部材(４６)は、キャリパボディ(８)の外周に配置しているので、内部に設ける場合と比較して、組み付けが容易であり、生産性を低下させる事はない。また、キャリパボディ(８)を分割可能とする事により、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。
【００２７】
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、前記荷重センサ(４８)と検知器本体(図示せず)とを接続するハーネス(５０)を、図１に示す如く、ボールねじ軸(３８)の中空部(４１)に挿通させている。また、ハーネス(５０)は、ボールねじ軸(３８)の進退移動量に合わせて、余裕を持たせた長さで中空部(４１)に配置しているが、この余裕部分の弛みが、部品相互の隙間に入り込んで、引掛かりや切断を生じる虞がある。
【００２８】
この不具合を解消するため、図１に示す如く、ハーネス(５０)を引張り発条(５１)にて引張り付勢し、弛み部分を常に中空部(４１)に配置して、中空部(４１)の外ではハーネス(５０)が常に張った状態となるようにしている。そして、ボールねじ軸(３８)が摩擦パッド(３)方向に前進して、ハーネス(５０)に引張り力が加わっても、引張り発条(５１)が伸張するので、ハーネス(５０)が切断されたり、ボールねじ軸(３８)の前進が阻害される事はない。また、ボールねじ軸(３８)が後退すると、引張り発条(５１)が復元収縮するので、ハーネス(５０)が中空部(４１)以外の位置で弛む事はない。
【００２９】
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、ボールねじ軸(３８)の進退量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１、図２、図７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ものとなる。
【００３０】
更に、本実施例では、図１、図７に示す如く、遊星腕(１８)の径大部(２１)の後端面に臨ませて、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。
【００３１】
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。
【００３２】
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、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、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)が後退するので、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。
【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)が後退し、作用部(１０)側の摩擦パッド(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】
上記制動に於いて、減速ギア機構(１７)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。この減速ギア機構(１７)による減速作用を説明すると、例えば、太陽歯車(２６)の歯数を６３、この太陽歯車(２６)と噛合する遊星歯車(２３)の第１歯車部(２４)の歯数を１８、第２歯車部(２５)の歯数を１５、この第２歯車部(２５)と噛合するボールねじナット(３４)の減速歯車(３５)の歯数を５４とする。
【００３５】
まず、電動モータ(１５)により遊星腕(１８)が一方向に一回転すると、遊星腕(１８)に軸支した遊星歯車(２３)が、太陽歯車(２６)の外周を一方向に一周する。この場合、太陽歯車(２６)の歯数は６３で、第１歯車部(２４)の歯数は１８であるから、遊星歯車(２３)は、太陽歯車(２６)の外周を一周する際に、一方向に６３歯／１８歯＝３．５回転する。即ち、第１歯車部(２４)と同軸の第２歯車部(２５)も、一方向に３．５回転する。(第２歯車部(２５)の歯数は１５であるから、一周では３．５回転×１５歯＝５２．５歯分の変位となる。)
【００３６】
一方、ボールねじナット(３４)には、遊星腕(１８)の回転により、一方向への回転力(５４歯分)が作用する。また、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)により、減速歯車(３５)には、一方向とは逆方向に、３．５×(１５歯／５４歯)＝０．９７２２回転の回転力が作用する(歯数では、前記５２．５歯分)。この一方向と逆方向への回転力を合成すると、１＋(−０．９７２２)＝０．０２７８回転となる(歯数での計算では、減速歯車(３５)は、５４歯＋(−５２．５)＝１．５歯分、一方向に変位し、減速歯車(３５)は５４歯だから、１．５歯／５４歯＝０．０２７８回転となる)。従って、遊星腕(１８)の一方向への一回転に対して、ボールねじナット(３４)が、同一方向に０．０２７８回転する比率で減速が行われる。
【００３７】
【発明の効果】
本発明は上述の如く構成したもので、摩擦パッドと減速ギア機構との間に電動モータを配置した構造としているので、減速ギア機構に対する摩擦パッドの制動熱の影響を少なくする事ができる。また、このような構造とする事により、減速ギア機構の放熱性も向上し、適宜の冷却手段での冷却も容易となるから、摩擦パッドの制動熱や電動モータの熱が伝達されても、減速ギア機構の高温化を良好に防ぐ事ができる。従って、熱膨張による作動不良やグリスの劣化を防ぎ、減速ギア機構の作動の正確性と耐久性を向上させる事ができる。
【００３８】
また、高価なグリスの使用や厳密な断熱対策等による部品点数や製作工数の増加を防ぎ、生産性や組み付け性を向上して、製品の低コスト化が可能となる。また、分解や再組み付けも容易で、メンテナンス性にも優れた製品となる。また、キャリパボディが径大化する事がなく、電気式ディスクブレーキをタイヤホイール内に設置する際の、レイアウトの自由度が増すものとなる。また、摩擦パッドと減速ギア機構との間に電動モータを配置し、かつ減速ギア機構として遊星歯車機構を使用すれば、キャリパボディがディスク軸方向にも長尺とならず、製品全体がコンパクトとなり、レイアウトの自由度が更に増すものとなる。
【図面の簡単な説明】
【図１】本発明の一実施例で、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１のＡ−Ａ線断面図。
【図３】減速ギア機構の斜視図。
【図４】図３の背面図。
【図５】図３の側面図。
【図６】太陽歯車をバックプレートに固定する固定ピン付近の拡大図。
【図７】ソレノイド付近の拡大図。
【符号の説明】
１ディスクロータ
３摩擦パッド
４摩擦パッド
８キャリパボディ
１５電動モータ
１７減速ギア機構
１８遊星腕
２３遊星歯車
２６太陽歯車
３４ボールねじナット
３８ボールねじ軸[0001]
[Industrial application fields]
The present invention is mounted on various vehicles such as automobiles and motorcycles, and has an electric disc brake arrangement structure in which an advance / retreat operation mechanism is advanced / retracted by a driving force of an electric motor, and a friction pad is pressed and slid on a disc rotor to perform braking. The reduction gear mechanism that decelerates the driving force of the electric motor and transmits it to the advance / retreat operation mechanism is disposed at a position away from the friction pad, and prevents the reduction gear mechanism from becoming hot due to braking heat, It is intended to improve the accuracy and durability of the operation of the reduction gear mechanism.
[0002]
[Prior art]
Conventionally, in various vehicles such as automobiles and motorcycles, there is an electric disc brake that performs a braking operation by pushing and sliding a friction pad against a disc rotor by advancing and retracting a ball screw or the like by a driving force of an electric motor. To do. And as a reduction gear mechanism that decelerates the driving force of the electric motor and transmits it to the advance / retreat operation mechanism, as described in Japanese Patent Publication No. 10-504876, Japanese Patent Publication No. 3-500920, and Japanese Patent Publication No. 2001-524647. However, there is one using planetary gears, and the driving force of the electric motor can be efficiently reduced to generate a strong pressing force on the friction pad.
[0003]
[Problems to be solved by the invention]
However, in the conventional invention described in the above Japanese National Publication No. 10-504876 and Japanese National Publication No. 3-500920, gear parts such as planetary gears are arranged between the electric motor and the friction pad. Since the braking heat generated between the motor and the disk rotor and the heat of the electric motor are easily transmitted through the surface of the caliper body or as atmospheric heat and heat dissipation is poor, the temperature of the gear parts is likely to increase. Due to this high temperature, the gear parts are thermally expanded to cause a malfunction, and the grease such as grease that lubricates the gear parts is deteriorated.
[0004]
In order to prevent malfunctions due to thermal expansion, it is necessary to take heat insulation measures such as placing a heat insulating material between the friction pad and the reduction gear mechanism inside the caliper body. An increase may occur, and productivity and maintainability may be reduced. Further, in order to prevent the grease from deteriorating, it is necessary to use high temperature resistant grease, which increases the cost.
[0005]
In the invention described in JP-T-2001-524647, a reduction gear mechanism is formed by engaging a plurality of gears inside the electric motor, and the distance from the friction pad is increased. Compared to technology, braking heat is less likely to be transmitted to the reduction gear mechanism. However, since the working portion side of the caliper body is formed to be large in the radial direction, it is easy to receive layout restrictions when installing a product inside a narrow tire wheel from which a drive shaft or the like protrudes. Moreover, in the conventional invention of JP-T-3-500920, since the electric motor is not built in and is separately arranged at the rear part of the caliper body, the caliper body is long in the direction of the disk axis, although the diameter is not large. When installing this product, the layout may be restricted.
[0006]
The present invention is intended to solve the above-described problems, and allows the reduction gear mechanism to be disposed at a position that is not easily affected by the braking heat of the friction pad. Then, the reduction gear mechanism is prevented from being heated to improve durability, and smooth and accurate operation can be sustained. In addition, the grease used for the gear parts is prevented from deteriorating, the number of parts is prevented from increasing, and a low-cost product excellent in assemblability and maintainability is obtained. In addition, the caliper body is prevented from increasing its diameter, and a compact product is obtained to increase the degree of freedom in layout when installed on a vehicle.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention converts the rotational motion of a ball screw nut, which is rotated by the driving force of an electric motor, into a forward / backward motion of the ball screw shaft, so that the friction screw pad is used on the ball screw shaft. In an electric disc brake that provides a caliper body with an advancing / retreating operation mechanism that generates a pressing force on the pressing member, and that presses and slides a friction pad against the disc rotor by this advancing / retreating operation mechanism, the electric motor includes: The advance / retreat operation mechanism is accommodated on the inner periphery side, and a cylindrical cylindrical portion having a magnet disposed on the outer periphery is rotated, and the rotational force of the cylinder portion is decelerated and transmitted to the ball screw shaft of the advance / retreat operation mechanism. includes a reduction gear mechanism, the electric motor, the the rewritable disposed between the friction pad and the reduction gear mechanism, the reduction gear mechanism, times integrally with the cylindrical portion of the electric motor A planetary arm provided with a large diameter portion larger than the cylindrical portion on the rear side opposite to the friction pad, and pivotally supported on the outer periphery of the large diameter portion and opened on the outer periphery of the large diameter portion A planetary gear projecting outward from the cutout window, a sun gear fixed to the caliper body so as not to rotate, and meshing with the planetary gear to rotate the planetary gear, and meshing with the planetary gear Thus, the planetary gear reduction mechanism is provided with a reduction gear that rotates integrally with the ball screw nut of the advance / retreat operation mechanism.
[0008]
The advancing / retracting operation mechanism includes a planetary gear and a first gear portion and a second gear portion having a smaller number of teeth than the first gear portion, which are integrally formed separately in the axial direction. the first gear portion meshes with the sun gear that is non-rotatably secured to the caliper body, rotating by the rotation of the planetary gears at a diameter larger than the Yu star gear with meshing the second gear unit to the reduction gear It consists of a moving ball screw nut and a ball screw shaft that advances and retreats in the direction of the disk shaft by the rotation of this ball screw nut. By rotating the large ball screw nut with a planetary gear, a reduction gear mechanism The rotational force transmitted from the motor may be further decelerated to generate a pressing force on the pressing member via the ball screw shaft.
[0009]
[Action]
The present invention is configured as described above. By arranging the electric motor of the electric disc brake between the friction pad and the reduction gear mechanism, the reduction gear mechanism can be arranged at a position away from the friction pad. , The influence from the braking heat of the gear parts can be reduced. Further, at such a position of the reduction gear mechanism, heat dissipation is improved, and cooling by an appropriate cooling means is easy.
[0010]
Therefore, it is possible to prevent the reduction gear mechanism from being heated to a high temperature, to prevent malfunction due to thermal expansion of gear parts, deterioration of grease, etc., and to improve the accuracy and durability of the operation of the reduction gear mechanism. . In addition, strict heat insulation measures are not required, the number of parts and the manufacturing process can be prevented, productivity and assembly can be improved, and a low-cost product can be obtained. In addition, the caliper body can be easily disassembled and reassembled, and maintenance is improved when the vehicle is used. Further, the caliper body does not have a large diameter, and the degree of freedom in layout increases when an electric disc brake is installed inside the tire wheel.
[0011]
The reduction gear mechanism may be any conventionally known mechanism as long as it has a structure in which an electric motor is interposed between the friction pad and, for example, a planetary arm that can be rotated by an electric motor, and the planetary arm. The planetary gear mechanism may be composed of a planetary gear that is pivotally supported on the outer periphery thereof and a sun gear that is fixed to the caliper body so as not to rotate and that rotates the planetary gear.
[0012]
Due to the action of the planetary gear mechanism, the driving force of the electric motor is efficiently decelerated and converted into a strong pressing force of the friction pad by the ball screw shaft, and good braking is performed. Also, by using a planetary gear mechanism, the caliper body does not become large in diameter, it does not become long in the direction of the disc axis, and the entire electric disc brake device can be compactly formed and installed in the vehicle. The degree of freedom of layout at the time is further improved.
[0013]
The advance / retreat operation mechanism may be any conventionally known mechanism. For example, a ball screw nut having a diameter larger than that of the planetary gear of the speed reduction mechanism and rotating by rotation of the planetary gear, and the ball screw nut. Thus, a ball screw mechanism comprising a ball screw shaft that advances and retreats in the direction of the disk shaft can be used. By rotating the ball screw nut having a large diameter with the planetary gear, the driving force of the electric motor decelerated by the reduction gear mechanism is further decelerated. It is possible to efficiently convert to a force and generate a strong pressing force on the pressing member.
[0014]
【Example】
An embodiment of the present invention will be described below with reference to the drawings. (1) is a disk rotor which is connected to a driving wheel of an automobile and rotates integrally with it, facing the friction surfaces (2) on both sides. As shown in FIG. 1, a pair of friction pads (3) and (4) are arranged inside the tire wheel (5). Further, the bracket (6) is fixed to the vehicle body so as to face the disk rotor (1), and the caliper support arm (7) projecting from the fixed side across the outer periphery of the disk rotor (1) to the opposite side. ), The friction pads (3) and (4) are slidably disposed.
[0015]
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. In 9), they are linked so that they can move forward and backward. 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.
[0016]
As shown in FIG. 1, the action portion (10) is a ball as an advancing / retreating mechanism for generating a pressing force of the electric motor (15) and the friction pads (3) (4) in the cylinder (14). A screw mechanism (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).
[0017]
The planetary arm (18) is provided in a cylindrical part (20) having a magnet (39) on the outer periphery and a rear part opposite to the friction pad (3), and has a larger diameter than the cylindrical part (20). The inside of the cylinder (14) via the bearing portion (57) is driven by the driving force of the electric motor (15) arranged on the outer periphery of the magnet (39) of the cylindrical portion (20). It can be rotated. Then, planetary gears (23) are pivotally supported at three locations on the outer periphery of the large-diameter portion (21) at equal intervals so that the planetary gears (23) are large-diameter as shown in FIGS. The part (21) protrudes to the outside from a notch window (22) opened on the outer periphery. 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 rotor of the rotation angle sensor (19) described later. It can be used as
[0018]
The planetary gear (23) includes a first gear portion (24) and a second gear portion (25) having a smaller number of teeth than the first gear portion (24), as shown in FIGS. The first gear portion (24) is formed integrally with the front and rear in the axial direction, and meshed with a sun gear (26) fixed to the caliper body (8) so as not to rotate. 26) enables rotation of the planetary gear (23).
[0019]
The sun gear (26) is fixed, as shown in FIGS. 1, 3, and 6, by inserting insertion holes (29) at equal intervals in the back plate (27) disposed at the rear of the caliper body (8). The fixing pin (28) having a plurality of openings and inserted into the insertion holes (29) is inserted into the fixing holes (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.
[0020]
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) is engaged with the second gear portion (25) of the planetary gear (23), and the ball screw nut (34) can be rotated by the rotation of the planetary gear (23).
[0021]
In addition, a ball groove (36) is provided in the center of the ball screw nut (34) so that the ball screw shaft (38) can be advanced and retracted via a plurality of balls (37) as shown in FIGS. Screwed. As shown in FIG. 1, a flat pad pressing plate (40) is connected to the tip of the ball screw shaft (38) as a pressing member of one friction pad (3). 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 disc rotor (1). In this embodiment, an extendable dust seal (47) is connected between the outer periphery of the pad pressing plate (40) and the inner periphery of the cylinder (14) to close the opening (45) of the cylinder (14). Intrusion of dust, moisture, pebbles, etc. into the cylinder (14) can be prevented.
[0022]
As shown in FIG. 1, the ball screw shaft (38) and the pad pressing plate (40) are connected by penetrating the inside of the ball screw shaft (38) to provide a hollow portion (41). The mounting screw (42) is screwed into the bag hole-shaped mounting hole (43) recessed in the back surface of the pad pressing plate (40) from within the portion (41). By adopting such a configuration, 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 also 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) in this way, the assembling property and the maintenance property are improved.
[0023]
By configuring as described above, the reduction gear mechanism (17) can be disposed on the rear side opposite to the friction pads (3) and (4) via the electric motor (15). For this reason, the caliper body (8) of the present invention is compared with the case where the gear parts are arranged between the friction pad and the electric motor as in the prior art such as JP 10-504876 and JP 3-500920. ) Can suppress the transmission of braking heat to the gear parts.
[0024]
Even if the braking heat and the rotational heat of the electric motor (15) are transmitted through the surface of the caliper body (8) or the internal space, the sun gear (26), the planetary gear (23), the reduction gear (35 ) Is arranged on the rear side of the caliper body (8). Therefore, the heat dissipation is excellent compared to the case where the caliper body (8) is provided inside, and cooling with an appropriate cooling means is facilitated. Accordingly, the reduction gear mechanism (17) is highly effective in preventing the temperature from increasing, and the malfunction and deterioration of grease due to thermal expansion are prevented to improve the accuracy and durability of the operation of the reduction gear mechanism (17). Can do.
[0025]
In addition, in Japanese Patent Publication No. 2001-524647 of the prior art, a reduction gear mechanism is incorporated inside the electric motor, so that the caliper body is enlarged in diameter. In Japanese Patent Publication No. 3-500920, the electric motor is mounted on the caliper body. Since it is separately arranged at the rear part, the product is long in the direction of the disk axis, and both are restricted in layout at the time of installation. On the other hand, in this embodiment, the electric motor (15) is built in the caliper body (8), and the reduction gear mechanism (17) such as the planetary gear (23) is further rearward than the electric motor (15). Is arranged. Therefore, the caliper body (8) is neither long nor large in diameter, and can be made compact, increasing the degree of freedom in layout.
[0026]
In this embodiment, in order to further enhance the heat insulation effect on the reduction gear mechanism (17), the caliper body (8) can be divided into three parts before and after the electric motor (15). As shown in FIG. 1, a ring-shaped heat insulating member (46) having a lower thermal conductivity than the caliper body (8) is inserted and disposed. By this heat insulating member (46), braking heat of the friction pads (3) and (4) and rotational heat of the electric motor (15) are transmitted to the gear parts through the surface of the caliper body (8). This can further prevent the high temperature of the reduction gear mechanism (17) from being prevented. Further, since transmission of braking heat to the electric motor (15) is also prevented, malfunction due to high temperature of the electric motor (15) can also be prevented. Further, since the heat insulating member (46) is disposed on the outer periphery of the caliper body (8), it is easy to assemble compared to the case where it is provided inside, and the productivity is not lowered. Further, by making the caliper body (8) separable, it is possible to improve the ease of assembly and maintenance of various components inside the caliper body (8).
[0027]
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. A harness (50) for connecting the load sensor (48) and the detector body (not shown) is inserted through the hollow portion (41) of the ball screw shaft (38) as shown in FIG. . Further, the harness (50) is arranged in the hollow portion (41) with a sufficient length according to the amount of advancement and retraction of the ball screw shaft (38). There is a risk of getting caught and cut by entering the gaps.
[0028]
In order to solve this problem, as shown in FIG. 1, the harness (50) is tensioned and biased by the pulling ridge (51), and the slack portion is always arranged in the hollow portion (41), so that the hollow portion (41) Outside, the harness (50) is always in a tensioned state. Even if the ball screw shaft (38) moves forward in the direction of the friction pad (3) and a tensile force is applied to the harness (50), the tension ridge (51) extends, so that the harness (50) is cut. The advance of the ball screw shaft (38) is not hindered. Further, when the ball screw shaft (38) is retracted, the tension ridge (51) is restored and contracted, so that the harness (50) is not loosened at a position other than the hollow portion (41).
[0029]
In addition, the caliper body (8) is provided with a rotation angle sensor (19) for detecting the rotation angle of the planetary arm (18) and estimating the advance / retreat amount of the ball screw shaft (38). As shown in FIGS. 1, 2, and 7, the rotation angle sensor (19) is disposed on the inner peripheral surface of the cylinder (14) and on the outer periphery of the triangular large diameter portion (21) of the planetary arm (18). In addition, the configuration is such that magnetic coils are 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). This will prevent an increase in assembly man-hours.
[0030]
Further, in this embodiment, as shown in FIGS. 1 and 7, the back plate (27) faces the rear end face of the large diameter portion (21) of the planetary arm (18) and the solenoid (54) of the parking mechanism. 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.
[0031]
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).
[0032]
Then, due to the action of the ball screw mechanism (16), the rotational force is converted into the sliding force of the ball screw shaft (38), and the friction pad (3) on the action part (10) side is moved through the pad pressing plate (40). Press and slide and press against the disc rotor (1). Further, since the caliper body (8) is retracted by the sliding reaction force of the ball screw shaft (38), the reaction force claw (11) of the reaction portion (12) is moved to the friction pad on the reaction portion (12) side ( 4) is pressed and slid and pressed against the disk rotor (1) to perform braking.
[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). Since it rotates in the direction, the ball screw shaft (38) retreats, and the pressing of the friction pad (3) on the action part (10) side 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]
In the above braking, the driving force of the electric motor (15) is efficiently decelerated by the action of the reduction gear mechanism (17) and can be converted into a strong pressing force of the friction pads (3) and (4). Effective braking is possible. The speed reduction action by the speed reduction gear mechanism (17) will be described. For example, the number of teeth of the sun gear (26) is 63, and the first gear portion (24) of the planetary gear (23) meshing with the sun gear (26) is used. The number of teeth is 18, the number of teeth of the second gear portion (25) is 15, and the number of teeth of the reduction gear (35) of the ball screw nut (34) meshing with the second gear portion (25) is 54.
[0035]
First, when the planetary arm (18) makes one rotation in one direction by the electric motor (15), the planetary gear (23) pivotally supported on the planetary arm (18) makes one rotation around the outer periphery of the sun gear (26). . In this case, since the number of teeth of the sun gear (26) is 63 and the number of teeth of the first gear portion (24) is 18, when the planetary gear (23) goes around the outer periphery of the sun gear (26), , 63 teeth / 18 teeth = 3.5 rotations in one direction. That is, the second gear portion (25) coaxial with the first gear portion (24) also rotates 3.5 times in one direction. (Since the number of teeth of the second gear portion (25) is 15, it is 3.5 rotations × 15 teeth = displacement of 52.5 teeth in one turn.)
[0036]
On the other hand, the rotational force (54 teeth) in one direction acts on the ball screw nut (34) by the rotation of the planetary arm (18). Further, the second gear portion (25) meshing with the reduction gear (35) of the ball screw nut (34) causes the reduction gear (35) to be 3.5 × (15 teeth / 54 teeth) = 0.9722 rotation force (in terms of the number of teeth, 52.5 teeth). When the rotational force in one direction and the opposite direction is combined, 1 + (− 0.9722) = 0.0278 rotations (in the calculation with the number of teeth, the reduction gear (35) has 54 teeth + (− 52. 5) = 1.5 teeth are displaced in one direction, and the reduction gear (35) is 54 teeth, so 1.5 teeth / 54 teeth = 0.0278 rotations). Accordingly, the ball screw nut (34) is decelerated at a rate of 0.0278 rotation in the same direction with respect to one rotation in one direction of the planetary arm (18).
[0037]
【The invention's effect】
The present invention is configured as described above. Since the electric motor is arranged between the friction pad and the reduction gear mechanism, the influence of braking heat of the friction pad on the reduction gear mechanism can be reduced. In addition, by adopting such a structure, the heat dissipation of the reduction gear mechanism is also improved, and cooling with an appropriate cooling means is facilitated, so even if braking heat of the friction pad or heat of the electric motor is transmitted, The high temperature of the reduction gear mechanism can be prevented well. Therefore, it is possible to prevent malfunction due to thermal expansion and deterioration of grease, and to improve the accuracy and durability of the operation of the reduction gear mechanism.
[0038]
In addition, the increase in the number of parts and the number of manufacturing steps due to the use of expensive grease and strict heat insulation measures can be prevented, and the productivity and assembly can be improved, thereby reducing the cost of the product. In addition, disassembly and reassembly are easy, and the product has excellent maintainability. Moreover, the caliper body does not increase in diameter, and the degree of freedom in layout when the electric disc brake is installed in the tire wheel is increased. If an electric motor is arranged between the friction pad and the reduction gear mechanism and a planetary gear mechanism is used as the reduction gear mechanism, the caliper body does not become long in the disk axis direction, and the entire product becomes compact. As a result, the degree of freedom in layout is further increased.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an electric disc brake installed to face a disc rotor in an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a perspective view of a reduction gear mechanism.
4 is a rear view of FIG. 3. FIG.
FIG. 5 is a side view of FIG. 3;
FIG. 6 is an enlarged view of the vicinity of a fixing pin for fixing the sun gear to the back plate.
FIG. 7 is an enlarged view of the vicinity of the solenoid.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Disc rotor 3 Friction pad 4 Friction pad 8 Caliper body 15 Electric motor 17 Reduction gear mechanism 18 Planetary arm 23 Planetary gear 26 Sun gear 34 Ball screw nut 38 Ball screw shaft

Claims

An advancing / retracting operation mechanism that generates a pressing force on the pressing member of the friction pad by the ball screw shaft by converting the rotational motion of the ball screw nut that rotates by transmitting the driving force of the electric motor into the advancing / retreating motion of the ball screw shaft. In the caliper body, and in this electric disc brake that performs braking by pressing and sliding the friction pad on the disc rotor by this advance / retreat operation mechanism, the electric motor accommodates the advance / retreat operation mechanism on the inner peripheral side. A reduction gear mechanism that rotates a cylindrical portion having a magnet disposed on its outer periphery, decelerates the rotational force of the cylindrical portion, and transmits it to the ball screw shaft of the advance / retreat operation mechanism, and the electric motor includes: the rewritable disposed between the friction pad and the reduction gear mechanism, the reduction gear mechanism, the cylindrical portion to the rear portion of the side opposite to the cylindrical portion and the friction pad rotates integrally of the electric motor A planetary arm provided with a large-diameter portion, and a planetary gear that is pivotally supported on the outer periphery of the large-diameter portion and protrudes to the outside from a notch window that opens to the outer periphery of the large-diameter portion; A sun gear fixed to the caliper body so as not to rotate and meshing with the planetary gear to rotate the planetary gear; and meshing with the planetary gear so as to be integrated with the ball screw nut of the advance / retreat operating mechanism. An arrangement structure of an electric disc brake, characterized in that it is a planetary gear reduction mechanism provided with a rotating reduction gear .

The advancing / retracting operation mechanism is configured such that a planetary gear is integrally formed with a first gear portion and a second gear portion having a smaller number of teeth than the first gear portion, separated in the axial direction, and integrally formed. the part, meshes with a sun gear that is non-rotatably secured to the caliper body, rotated by the rotation of the planetary gears at a diameter larger than the Yu star gear with meshing the second gear unit to the reduction gear It consists of a ball screw nut and a ball screw shaft that advances and retreats in the direction of the disk shaft by the rotation of this ball screw nut. By rotating the large ball screw nut with a planetary gear, it is transmitted from the reduction gear mechanism. 2. The electric disc brake arrangement structure according to claim 1, wherein the rotating force generated is further decelerated to generate a pressing force on the pressing member via the ball screw shaft.