JP2004254361A

JP2004254361A - Molded type eccentric rotor, its manufacturing method and axial air-gap type core-less vibration motor having the rotor

Info

Publication number: JP2004254361A
Application number: JP2003039510A
Authority: JP
Inventors: Tadao Yamaguchi; 忠男山口; Masahiro Takagi; 正弘高城; Satoru Shimosegawa; 悟下瀬川; Katsuhito Sohara; 勝仁蘇原
Original assignee: Tokyo Parts Ind Co Ltd
Current assignee: Tokyo Parts Ind Co Ltd
Priority date: 2003-02-18
Filing date: 2003-02-18
Publication date: 2004-09-09
Anticipated expiration: 2023-02-18
Also published as: JP3546207B1

Abstract

<P>PROBLEM TO BE SOLVED: To propose a molded type eccentric rotor which can place an air-core armature coil at a predetermined position so as to place the air-core armature coil on a printed circuit board and which can be injection-molded from the printed circuit board side, to further thin a motor by being combined with such an eccentric rotor and to further thin a vibration motor by improving a brush base and a bracket. <P>SOLUTION: The molded type eccentric rotor has first and second surfaces. A shaft inserting hole is formed at the center of rotation. An air-core armature coil placing area is provided by being radially outwardly eccentrically deviating from the shaft inserting hole. A commutator made of a plurality of commutator segments is formed radially outward of the shaft inserting hole on the first surface. A plurality of the air-core armature coils 2A are arranged on the printed circuit board 1 having a recess for a gate port formed on the outer periphery. An eccentric weight 3 having a positioning guide formed at an opposite side via the center of rotation is arranged, and is integrally molded with the air-core armature coil from the first surface side via the recess with a resin 4 by molding. Since the eccentric weight 3 has a small diameter and a flat shape, even when the area of the printed circuit board for constituting the commutator is small, the air-core armature coil and the eccentric weight can be accurately integrally molded by filling the resin from the printed circuit board side. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【産業上の利用分野】
この発明は、移動体通信機器のサイレントコール手段などに用いられるモールド型偏心ロータとその製法の改良に係り、同ロータを備えた扁平薄型な軸方向空隙型コアレス振動モータの構成に関する。
【０００２】
【従来の技術】
従来ロータ自体で遠心力により振動を発生させるようにしたモールド型偏心ロータは、古くは本出願人らの提案によるものとして空心電機コイルを片側に偏在させた平面視半月型の偏心ロータからなるものがある。（特許文献１参照）
しかしながら、移動体通信機器の小型薄型化志向に伴い、移動体通信機器に搭載される部材もより小型薄型化が要求される。たとえば、直径が１２ｍｍ、厚みが３ｍｍ程度のサイズのものが要求されるようになると、従来直径１４ｍｍ程度のものでは好適な構造とした空心電機コイルを片側に偏在させた平面視半月型偏心ロータでは、重心の移動量が少なくなって遠心力振動が不足するようになるので、高比重部材からなる補助ウエイトが必要になってくる。
【０００３】
このため、モールドする樹脂をタングステン合金粉末あるいはブロックからなる高比重部材を樹脂に一体化、いわゆる２色成形にして重心の移動と重量を得るようにしたものが本出願人から提案されている。（特許文献２）
このようなモールド型偏心ロータは、空心電機子コイルを載置する印刷配線板に当該空心電機子コイルの内径に合わせたガイド孔と、巻き始め結線パターンが設けられ、当該空心電機子コイルを載置した後、印刷配線板を下方にして上方の空心電機コイル側から射出成形によって一体モールドされるようになっている。（特許文献３、４参照）
【０００４】
また、このような偏心ロータを備えた扁平型振動モータを移動体通信機器のサイレントコール手段として使用するには、機器の印刷配線板に両面粘着剤などを介して直接載置するため、取り付け面は平坦が要求される。
また、ブラシに電力を供給する給電端子はモータの側周部に導出され、機器の印刷配線板に設けられた給電パターンへ接続されるようになっている。
このような扁平型モータは、軸方向界磁型リング状マグネットで駆動されるので、このマグネットの内径部分に配されたブラシに電力を供給する給電構造に工夫が必要である。
【０００５】
このような薄型コアレス振動モータは、たとえば、特開平１０−２６２３５２号公報（特許文献５参照）として開示されたように、ブラケットにブラシベースの形状に合わせてプレス加工によって凹所を形成し、この凹所にブラシベースを埋め込むことにより、ブラスベースの厚みを無視できるようにしたものがある。
しかしながら、プレス加工で凹所を押し潰して形成するのは、かなりのブラケットの厚みが必要であり、このため、従来の技術では厚さが２．５ｍｍ程度が限界であった。すなわち、ブラケットの厚みが０．１５ｍｍ程度になると、部分的に０．１５ｍｍを潰すことはできないものである。
【０００６】
【特許文献１】特開平６−２０５５６５号公報
【特許文献２】特開平１１−７５３４２号公報
【特許文献３】特開平８−１６３８４６号公報
【特許文献４】特開平１１−１１３２３１号公報
【特許文献５】特開平１０−２６２３５２号公報
【０００７】
【発明が解決しようとする課題】
小型化要求に伴い直径が１０ｍｍ、厚みが２ｍｍといった偏平で小型のモータが期待されるようになると、ロータ自体で遠心力振動を発生させるには、今度は比重１８程度のタングステン合金の助けが必要になってくる。
そして、小型化に伴いコンミテータを構成する印刷配線板の面積が減少して配線パターンのスペースを確保するのが難しくなり、コイル位置決めガイドを挿通する孔の確保が困難になる。
また、偏心ウエイトも振動量を確保するのにできるだけ大きいものが必要となるため、印刷配線板上の部品配置密度が高くなりこれら部品の間に射出成型用のゲートを配置することが困難となった。
そこで、この発明は、印刷配線板に空心電機子コイルを載置するにあたって空心電機子コイルを所定位置に載置可能とし、印刷配線板側から射出成形できるモールド型偏心ロータを提案し、このような偏心ロータと組みあわせ、モータをより薄型化できるようにするのを目的としたものである。また、ブラシベースとブラケットを改良することにより、振動モータをさらに薄型化することを目的とする。
【０００８】
【課題を解決するための手段】
上記課題の基本的な解決は、請求項１に示す発明のように、回転中心に軸挿通孔が設けられると共に、その半径方向外方に偏心して空心電機子コイル載置エリアがあり、第１の面で前記軸挿通孔の半径方向外方に複数個の整流子セグメントからなる整流子部が形成され、外周部にゲート口用凹所が形成され、さらに端末結線パターンが形成された印刷配線板と、この印刷配線板の前記第２の面の空心電機子コイル載置エリアに配された複数個の空心電機子コイルと、中心を介して前記空心電機子コイルの反対側に位置する偏心ウエイトとが前記空心電機子コイル共に前記凹所を介して第１面側から樹脂によって一体成形されたモールド型偏心ロータで達成できる。
このようにすれば、印刷配線板に空心電機子コイル載置ガイド用穿孔を設けることなく、外周のゲート口用凹所で印刷配線板側から射出成形でき、偏心ウエイトを空心電機子コイルと共に一体成形できる。
【０００９】
本願発明は、請求項２に示す発明のように焼結含油軸受けを一体に成形することも可能で、モールド型偏心ロータの回転制度をより高めることができる。
さらに請求項３の発明のように、円筒状の軸受けの外周に連続した帯状の凸部あるいは不連続の凸部を設けることで、軸受と樹脂の結合強度が高めることができ、さらに凸部で印刷配線板を支持することが可能となる。
また、請求項４に示す発明のように前記樹脂は密度が２以下の軽量樹脂で構成され、前記印刷配線板は偏心ウエイトの部分が削除されているものにするのがよい。
このようにすれば、空心電機子コイル側は樹脂と銅線の密度、占積率より実質的な密度を４以下にすることができるので、偏心ウエイトとの比重差によってウエイト側に大きく重心が移動することになる。そして、印刷配線板の厚み分偏心ウエイトを厚くできるので振動量を増すことが可能となる。
【００１０】
また、請求項５に示す発明のように、前記ゲート口用凹所は前記印刷配線板の外周で前記複数の空心電機子コイルの間に形成されているものがよい。
このようにすれば、樹脂の流れを良くできるので小径の偏心ロータに好都合となる。
さらに、このモールド型偏心ロータを製造するには、請求項６に示す発明のように第１、第２の面があり、中心に軸挿通孔が設けられると共に、その半径方向外方に空心電機子コイル載置エリアがあり、第１の面で前記軸挿通孔の半径方向外方に形成された複数個の整流子セグメントとからなる整流子部が形成された印刷配線板と空心電機子コイルを、ガイドを利用して前記印刷配線板がゲート側となるよう射出成形金型へ装着し、位置決めガイドを利用して偏心ウエイトを配し、前記空心電機子コイルの載置部外で前記印刷配線板の外周部に形成されたゲート口用凹所のところで第１面側から射出成形してなるものにするのがよい。
このような製造方法によれば、空心電機子コイルの内径部の小さいものでも印刷配線板に載置でき、偏心ウエイトと容易に一体化できる。
【００１１】
そして、請求項７、８に示すように、請求項１〜５のいずれか１項に記載のモールド型偏心ロータと、この偏心ロータを支承する軸と、この軸を支承するハウジングと、前記偏心ロータに空隙を介して臨ませるようにハウジングに一部に配されたマグネットと、このマグネットの内径部でブラシベースに配されたブラシとを備え、前記ブラシベースの一部が前記マグネット下方を通ってハウジング側方に給電電極として導出されたものにするか、前記軸は少なくとも一端が前記ハウジングに固定されると共に、このハウジングを構成するケースの開口部にブラケットが組み付けられ、前記ハウジングは厚みが０．２ｍｍ以下で構成されると共に、前記ブラシベースはフレキシブルで接着層を含めた厚みが０．１８ｍｍ以下で構成され、前記ハウジングはマグネットが配される部分の一部に透孔が設けられ、この透孔を通って前記ブラシベースの一部がハウジング側方に給電電極として導出されているもので達成できる。
このようにすれば、扁平型モータが容易に得られ、ブラケットの厚みを０．２ｍｍ以下にしても、プレス押圧等の無理な手段を採用しなくても、透孔加工によるブラシベース導出手段が容易にでき、フレキシブルなブラシベースは通常０．１５程度のため、透孔を通してモータの側周に容易に導出できるので厚みを増加させる怖れもない。このとき、ブラシベースは透孔とマグネットによって押さえられるので、ブラシ摺接部分に図において、下方の力が加わっても、ブラシ固定部のブラシベースの浮きが防止できる。
【００１２】
【発明の実施の形態】
次に、この発明の実施の形態の図面を説明する。
図１は、この発明のモールド型偏心ロータＲの下面Ｒ１側から見た図である。
図２は、モールド型偏心ロータＲの上面Ｒ２側から見た図である。
図３はこのモールド型偏心ロータの第１の組立図である。
図４は、同第２の組立図である。
図５は、同ロータを備えた軸方向空隙型コアレスモータの断面図である。
図６は、同ロータを備えた軸方向空隙型コアレスモータの断面図で、焼結含油軸受を用いない実施例を示す。
【００１３】
以下、上記各図面に基づく本願の実施形態を説明する。
図１，図２に円盤形状にモールド成形された偏心ロータＲの平面図を示す。図１は後述の印刷配線板第１の面１ａ側から見た下面Ｒ１の図であり、図２は図１の裏側でやはり後述の空心電機子コイル側から見た上面Ｒ２の図である。
この偏心ロータＲは、下面Ｒ１に印刷配線板１、焼結含油軸受Ｊの一方の端部および位置決めガイド孔３ｂを有する偏心ウエイト３が、上面Ｒ２に空心電機子コイル２Ａ、２Ｂ、２Ｃ、偏心ウエイト３および焼結含油軸受けＪの他方の端部が実線で示すよう露出して、他の部分にはそれらの隙間を充填するように樹脂４が射出成形により成形されている。
【００１４】
印刷配線板１はその上面Ｒ２側である第２の面１ｂに３個の空心電機子コイル２Ａ、２Ｂおよび２Ｃを円盤の片側に寄せて載置するようほぼ半月状に形成されている。そして、その回転中心に軸挿通孔１ｃが設けられ、その軸挿通孔１ｃ周囲の下面Ｒ１側である第１の面１ａには、複数個の整流子セグメントからなる整流子部１ｓが軸挿通孔１ｃを囲んで形成されている。
印刷配線板１にはこの他に空心電機子コイル２Ａ、２Ｂ、２Ｃの巻き線端末を各セグメントパターンへ接続する端末結線パターンや、火花防止用印刷抵抗あるいは必要に応じて印刷コイル等が設けられるが図示を省略する。
【００１５】
図２で示すように、空心電機子コイル２Ａ、２Ｂ、２Ｃは配置角８０度で印刷配線板１の第２の面１ｂに設けられた載置エリア１ｄに載置されている。また、整流子部Ｓが軸挿通孔１ｃを囲んでいるため、印刷配線板１は円盤の回転中心を含む線より突き出した部分を持つ半月状に形成されている。
空心電機子コイル２Ａ、２Ｂ、２Ｃは巻線で形成され、所定厚みで導体部の開角が６０度となり、中央に巻軸形状の空間を有するよう形成されている。コイル外形を小さくするため、このコイルの内側空間も小さいものとなっている。
【００１６】
偏心ウエイト３は所定の幅、厚みを有する円弧状で形成され、その幅は偏心ロータＲの円盤直径より突出しない範囲で、その厚みは空心電機子コイル２Ａ、２Ｂ、２Ｃと印刷配線板１を合わせた厚みとして偏心ロータＲの外形および厚みで小型化に影響しないようにしてある。
また、偏心ウエイト３には偏心ロータＲの成型時に偏心ウエイト３の位置を決定する位置決めガイド孔３ｂが厚み方向に貫通して２個設けられ、外周部および直線の部分には面取りが施されチャンハ３ａを形成している。
さらに、偏心ウエイト３には凹所３ｅを設け、ここへ射出成型時に必要なゲートを配置し、凹所３ｅにより樹脂の流れをより良くする。
偏心ウエイトは銅タングステン合金製で、モータサイズ、たとえば直径１４ｍｍ〜１０ｍｍなどに応動して消費電流と遠心力を勘案して密度（比重）が１５〜１８．４のものが選定される。
【００１７】
印刷配線板１の外周部にはゲート口用凹所（１ｅ）が形成されている。これは、印刷配線板１の外周に切り欠きを配置し、射出成型時ここから樹脂４を注入することで、樹脂注入を印刷配線板１側から行えるようにすると共に、印刷配線板１の内部に開口を形成しなくても良いようにするためである。このゲート口用凹所１ｅは空心電機子コイル２Ａと２Ｂの間および２Ｂと２Ｃの間に位置するよう設けられている。
本実施例では半円形としているが、角形や楕円等も考えられ、特に半円形に限定されない。
【００１８】
焼結含油軸受Ｊは円筒形状で印刷配線板１の軸挿通孔１ｃに設けられ、後述の軸８により偏心ロータＲをブラケット７へ回転自在に支持する。また、その円筒軸方向中央部には、円周上に凸部Ｊａが設けられている。
この凸部Ｊａにより焼結含油軸受Ｊはモールド成形後、偏心ロータＲに対する軸方向への抜け強度を増強することができる。
また、凸部Ｊａは筒状の焼結含油軸受Ｊの外周全周に亘らず断続して形成しても同様の効果が得られ、さらに回転方向に対する取り付け強度も強くすることができる。
偏心ロータＲはこれら印刷配線板１、空心電機子コイル２Ａ、２Ｂ、２Ｃ、偏心ウエイト３および焼結含油軸受Ｊが樹脂４に一体にモールド成形されたものである。
樹脂４は、重心位置をできるだけ相殺してしまわないように密度（比重）が少なく、成形性と再生性のよいポリブチレンテレフタレート樹脂など密度が２以下のもので、できればガラス繊維の入った強度のある１．４程度のものが選定される。
【００１９】
このような偏心ロータＲを製造する方法について図３、図４を用いて説明する。図３はジグを用いた準備作業であり、図４は射出成形金型を用いたモールド成型である。
図３により準備作業を説明する。
空心電機子コイル２Ａ、２Ｂ、２Ｃを印刷配線板１に載置するジグ５には、空心電機子コイル２Ａ、２Ｂおよび２Ｃの巻き軸寸法に合わせた配置ガイド５Ａ、５Ｂおよび５Ｃが設けられている。この配置ガイド５Ａ、５Ｂ、５Ｃは配置開角８０度で空心電機子コイル２Ａ、２Ｂおよび２Ｃの厚み内でジグ上面から突き出し形成されている。
ジグ上面にはさらに、印刷配線板１の外周に形成した半円型の凹所１ｅが入る位置決めピン５Ｆ、５Ｆと印刷配線板１の軸挿通孔１ｃの位置にピン５Ｄを配置する。
準備作業における組立方法は次の通りである。
まず、各空心電機子コイル２Ａ、２Ｂおよび２Ｃをジグ５の配置ガイド５Ａ、５Ｂおよび５Ｃにはめ込み、各空心電機子コイル２Ａ、２Ｂおよび２Ｃ上方の面に接着剤（ここでは嫌気性紫外線硬化型）を塗布する。
つぎに印刷配線板１を、軸挿通孔１ｃとピン５Ｄを、ゲート口用凹所１ｅと位置決めピン（５Ｆ、５Ｆ）をそれぞれ合わせて被せ、少し押圧して仮接着して射出成形前の第１の準備作業をする。
【００２０】
その後、各空心電機子コイル（２Ａ、２Ｂおよび２Ｃ）の各所定の端末を、印刷配線板１上に設けた端末結線パターンに半田、あるいは熱溶着などで結線する。
その結線部分を紫外線硬化型接着剤を塗布した上でコイルに塗布した紫外線硬化型接着剤とともに紫外線照射し、結線部分を保護するとともに印刷配線板に対してコイルを固定する。
【００２１】
次に図４によりモールド成型について説明する。
射出成型用下型５５には、成型により円盤を形成する凹部内にジグ５の配置ガイド５Ａ、５Ｂおよび５Ｃと同寸に射出成型用配置ガイド５５Ａ、５５Ｂおよび５５Ｃを形成し、さらに、所定の位置に偏心ウエイト３の位置決めガイド孔３ｂに入るガイドピン５Ｅ、５Ｅを立ちあげる。そして中心に焼結含油軸受けＪを装着する軸受装着ピン５Ｇを立ち上げる。
【００２２】
射出成形上型５６には、印刷配線板ゲート用凹所１ｅに対応する箇所に印刷配線板ゲート口５６ｅが設けられ、また必要に応じて偏心ウエイトゲート口用凹部３ｅに対応する位置に偏心ウエイトゲート口５６ｃが設けられている。
このゲート口５６ｅ、５６ｃは、ゲート用凹所１ｅ、３ｅが大きく構成できれば凹所内に収まるよう構成する。また、ゲート用凹所１ｅ、３ｅの大きさが限られる場合、ゲート口５６ｅ、５６ｃの開口を射出成形下型５５のパーティング面にかかるよう、いわゆるハーフゲートとしても良い。
また、ゲートの周囲を、成形後の樹脂４がゲート口用凹所１ｅ、３ｅに収まる範囲で厚み方向凹状態となるよう形成しても良い。これは、ピンゲート等でも切り離し時に処理跡が微少量凸状に形成されるので、その処理跡を偏心ロータＲの第１の面から突出するのを防止できる。
半径方向に余裕がある場合は、このゲート用凹部１ｅ、３ｅの側面にゲートを設け、サイドゲートとして射出成形しても良い。
【００２３】
この射出成型用下型５５と射出成形上型５６を用いたモールド成形工程について説明する。
先ず、焼結含油軸受Ｊを軸受け挿着ピン５Ｇに装填し、空心電機子コイル２Ａ、２Ｂ、２Ｃが取り付けられた印刷配線板１を、板面が上になるように、かつ各空心電機子コイルの巻軸形状の空間を前記射出成型用配置ガイド５５Ａ、５５Ｂおよび５５Ｃに合わせて装填する。また、偏心ウエイト３をガイドピン５Ｅ、５Ｅに合わせて射出成型用下型５５へ装着する。
次に射出成型用上型５６を降ろして半円型の凹所１ｅの位置と、偏心ウエイトゲート口５６ｃの位置から樹脂４を射出することによってモールド型偏心ロータ（Ｒ）を完成させる。
【００２４】
以上述べた製造方法は準備作業工程を用いるとして説明したが、偏心ウエイト３を印刷配線板１の位置決めに用いるようにすれば、図３に示す準備作業工程を省略することも可能である。
すなわち、偏心ウエイト３は印刷配線板１を含んだ厚みとなっていることから、その内周部形状を印刷配線板１の外形と同一とすることで偏心ウエイト３を印刷配線板１の位置だし部材として用いることができる。
【００２５】
これまで述べたように、印刷配線板１の外周部に設けたゲート口用凹所１ｅを設けたことで、これまで偏心ロータの第２の上面側へゲートを設けて射出成形によるモールド成形していたものが、下面である印刷配線板１の第１の面１ａ側から可能となる。
また、空心電機子コイルの位置決めを行うガイドピンを挿通する孔を印刷配線板へ設ける必要が無く、印刷自由度が増すことになる。
さらにゲート口用凹所を空心電機子コイル間に設けたので、樹脂がコイル間を通り樹脂廻りが良くなる。
偏心ウエイトにはその外周部等にチャンハ３ａを設けることで樹脂廻りが良くなると共に、軸方向に強度を有して印刷配線板１や空心電機子コイルと一体化できるので、偏心ウエイト３の部分に印刷配線板１が形成されていなくても良く、印刷配線板の厚みを偏心ウエイトにできるため偏心量を増すことができる。
【００２６】
図５は、前述のモールド型偏心ロータを採用し、厚み２ｍｍ程度に構成した超薄型コアレス振動モータを示す。
この振動モータは０．１５ｍｍの薄い磁性ステンレス板を絞り加工したケース６とこのケースの開口部に取り付けた０．１５ｍｍ程度のブラケット７でハウジングＨが構成されている。
内部には、前記ブラケット７の中心に太さ０．５ｍｍ程度の軸８が圧入固定され、この軸８の半径方向外方に薄いリング状マグネット９が載置されている。
ここで軸８の基端８ａは圧入の代わりにレーザ溶接してもよい。
軸８には、厚み０．６５ｍｍ程度のモールド型偏心ロータＲが回転自在に装着され、軸方向空隙を介して前記リング状マグネット９に臨ませている。
【００２７】
このモールド型偏心ロータＲは、前記のように３個の電機子コイルと１個の偏心ウエイトからなり、整流子部１ｓを介して一対のブラシ１０、１１により電力を受けるようになっている。ここでは偏心ロータＲは図２のＡ−Ａ断面図で表している。
前記ブラケット７には、ちょうどマグネット９の位置の一部が透孔７ａとなっていて、ブラシ１０、１１は基部が半田付あるいは熱溶着などでフレキシブルベース１２に植設され、給電リード部分１２ａを半径方向へ延在させて透孔７ａを通してケース６の側周に給電電極部１２ｂとして導出される。
したがって、フレキシブルベース１２をマグネット９とブラケット７の間から外方に導出するに当たって、この０．１５程度厚みを有するフレキシブルベース１２の導出空間を容易に確保できることになる。
【００２８】
ここで前記フレキシブルベース１２は所定の面に接着剤が付着されていてブラケット７、マグネット９に接着固定するのがよい。
フレキシブルベース１２の給電電極部１２ｂはブラケット７より突き出された舌片７ｂの部分で折り返され、３方向に半田電極がむき出されて容易に機器側の印刷配線板に半田結線できるようになっている。
【００２９】
一方ハウジングの他部を構成するケース６は、中央に前記細手のステンレス製の軸８の他端が装着されるバーリング状透孔６ａが配され、この透孔６ａの周囲にポリイミドフイルムＰを配着する。このポリイミドフイルムＰには前記モールド型偏心ロータＲが前記軸受Ｊを介して前記一対のブラシ１０、１１の押接力によって摺接されている。
このため、偏心ロータＲは常時ケース６側に付勢され、ポリイミドフイルムＰで回転自在に押さえられるので、それ以上にケース６側に移動して当たるおそれがなく、ケース６との空隙を常に一定にして回転位置がばらつくこともなく安定して回転支承させることができる。
【００３０】
ここで、前記軸８の他端は前記ケースに前記バーリング状透孔６ａの部分でレーザ溶接されている。
したがって、前記軸８は落下などの衝撃が加わっても透孔から外れてしまうおそれはない。
上述の実施の形態では、空心電機子コイルを３個使用する例を示したが、コイルを２個使用し偏心ウエイトを大きくする構成も可能である。
【００３１】
図６に、本願の他の実施例である偏心ロータを用いた振動モータを示す。
この振動モータは、偏心ロータＲに焼結含油軸受を設けることなく軸受け部を樹脂４で形成した例である。軸受け部を樹脂４で一体に形成することにより部品点数が減り、部品コスト、作業コストを削減することができる。
この構成とする場合、射出成形金型にはこの軸受け部を形成する凹部を設けておけばよい。
また、本実施の形態では偏心ロータＲに軸受け部を設ける、いわゆる軸固定型のモータを示したが、軸を偏心ロータＲへ一体成型する軸回転型モータであっても良い。
その場合、樹脂成形金型には回転軸を装着できる孔を設けておけばよい。
【００３２】
以上本願実施例でモールド型偏心ロータと同ロータの製法及び同ロータを備えた軸方向空隙型コアレス振動モータを説明したが、印刷配線板１を円形に構成し、偏心ウエイト３を用いないことで、通常のモールド型ロータおよび同ロータの製法および同ロータを備えた軸方向空隙型コアレスモータを提供することも可能である。
【００３３】
すなわち、印刷配線板１を円形に形成し、複数の空心電機子コイル２Ａ、２Ｂ、２Ｃを均等に配置する。（コイルの個数が３個の場合は配置角１２０度）
そしてゲート口用凹所をコイルの間に位置するよう設けることで印刷配線板側から樹脂を注入して射出成形し、印刷配線板１と空心電機子コイル２Ａ、２Ｂ、２Ｃおよび焼結含油軸受Ｊを一体に形成することができる。
また、この場合も焼結含油軸受Ｊのかわりに軸を一体として軸回転型モータとし、軸をモータケース外部へ突出させて出力軸とすれば通常のモータとして使用可能である。
また、ロータの外周にギヤを設け、そのギヤをモータケースの外部へ露出させて出力手段に用いるようにすれば、軸固定型のロータにより構成することもできる。
図３、図４における製造方法については、偏心ウエイト、各ガイドの位置以外は共通であり、その作用および効果も同様共通である。
【００３４】
【発明の効果】
この発明は上記のように構成したので、印刷配線板に空心電機子コイルを載置するにあたって印刷配線板が小さいものであって、印刷配線板側に空心電機子コイルガイド用穿孔を設けることができないようなものであっても容易に載置でき、印刷配線板側から射出成形できるモールド型偏心ロータにしたので、ブラケットに工夫を加えてモータの厚みを２ｍｍ程度にできる軸方向空隙型モータができる。
【００３５】
請求項１の発明では、外周のゲート口用凹所で印刷配線板側から射出成形することで印刷配線板に空心電機子コイル載置ガイド用穿孔を設けることなく、印刷配線板、偏心ウエイトおよび空心電機子コイルを共に一体成形できる。
請求項２の発明では、空心電機子コイル側は樹脂と銅線の密度、占積率より実質的な密度を４以下にすることができるので、偏心ウエイトとの比重差によってウエイト側に大きく重心が移動することになる。
【００３６】
請求項５の発明では、樹脂の流れが良くなるので小径の偏心ロータに好都合となる。
請求項６の発明では、空心電機子コイル、印刷配線板および偏心ウエイトを容易に一体化できる。
【００３７】
請求項７および請求項８の発明では、ブラケットの厚みを０．２ｍｍ以下にしても、プレス押圧等の無理な手段を採用しなくても、透孔加工によるブラシベース導出手段が容易にでき、フレキシブルなブラシベースは通常０．１５ｍｍ程度のため、透孔を通してモータの側周に容易に導出できるので厚みを増加させる怖れもない。このとき、ブラシベースは透孔とマグネットによって押さえられるので、ブラシ摺接部分の図において、下方の力が加わっても、ブラシ固定部のブラシベースの浮きが防止できる軸方向空隙型モータが得られる。
【図面の簡単な説明】
【図１】この発明のモールド型偏心ロータＲの上面側Ｒ１から見た図である。
【図２】モールド型偏心ロータＲの下面側Ｒ２から見た図である。
【図３】図１のモールド型偏心ロータの第１の組立図である。
【図４】同第２の組立図である。
【図５】図１のＡ−Ａ線切断の同ロータを備えた軸方向空隙型コアレスモータの断面図である。
【図６】同ロータを備えた軸方向空隙型コアレスモータの断面図で、焼結含油軸受けを用いない実施例を示す。
【符号の説明】
１印刷配線板
２Ａ、２Ｂ及び２Ｃ空心電機子コイル
３偏心ウエイト
４樹脂
５ジグ
Ｊ焼結含油軸受
６ケース
７ブラケット
Ｈハウジング
８軸
９マグネット
１０、１１一対のブラシ
１２フレキシブルベース[0001]
[Industrial applications]
The present invention relates to a mold-type eccentric rotor used for silent call means of a mobile communication device and an improvement of a manufacturing method thereof, and relates to a configuration of a flat thin axial-type air gap type coreless vibration motor provided with the rotor.
[0002]
[Prior art]
Conventionally, a mold-type eccentric rotor in which vibration is generated by centrifugal force in the rotor itself is an old eccentric rotor of a half-moon type in a plan view in which an air-core electric coil is unevenly distributed on one side as proposed by the present applicant. There is. (See Patent Document 1)
However, with the trend toward smaller and thinner mobile communication devices, members mounted on the mobile communication devices are also required to be smaller and thinner. For example, when a size having a diameter of about 12 mm and a thickness of about 3 mm is required, a plane view half-moon type eccentric rotor in which an air-core electric coil having a structure suitable for a conventional about 14 mm diameter is unevenly distributed on one side is required. In addition, since the amount of movement of the center of gravity becomes small and the centrifugal force vibration becomes insufficient, an auxiliary weight made of a high specific gravity member is required.
[0003]
For this reason, the present applicant has proposed that the resin to be molded is formed by integrating a high specific gravity member made of a tungsten alloy powder or a block into the resin, that is, so-called two-color molding to obtain the shift of the center of gravity and the weight. (Patent Document 2)
Such a mold-type eccentric rotor is provided with a guide hole corresponding to the inner diameter of the air-core armature coil and a winding start connection pattern on a printed wiring board on which the air-core armature coil is mounted. After being placed, the printed wiring board is turned downward, and is integrally molded by injection molding from the upper air core coil side. (See Patent Documents 3 and 4)
[0004]
Further, in order to use a flat type vibration motor having such an eccentric rotor as a silent call means of a mobile communication device, since the flat vibration motor is directly mounted on a printed wiring board of the device via a double-sided adhesive or the like, a mounting surface is required. Is required to be flat.
In addition, a power supply terminal for supplying power to the brush is led out to a side peripheral portion of the motor, and is connected to a power supply pattern provided on a printed wiring board of the device.
Since such a flat motor is driven by an axial field ring magnet, it is necessary to devise a power supply structure for supplying electric power to a brush disposed inside the magnet.
[0005]
In such a thin coreless vibration motor, for example, as disclosed in Japanese Patent Application Laid-Open No. H10-262352 (see Patent Document 5), a recess is formed on a bracket by press working in accordance with the shape of a brush base, and this recess is formed. There is one in which the thickness of the brass base can be ignored by embedding the brush base in the recess.
However, crushing the recess by pressing requires a considerable bracket thickness, and the conventional technology has a limit of about 2.5 mm in thickness. That is, when the thickness of the bracket is about 0.15 mm, the bracket cannot be partially crushed by 0.15 mm.
[0006]
[Patent Document 1] JP-A-6-205565
[Patent Document 2] JP-A-11-75342
[Patent Document 3] JP-A-8-163846
[Patent Document 4] JP-A-11-113231
[Patent Document 5] JP-A-10-262352
[0007]
[Problems to be solved by the invention]
With the demand for miniaturization, flat and small motors with a diameter of 10 mm and a thickness of 2 mm are expected, the help of a tungsten alloy with a specific gravity of about 18 is now required to generate centrifugal vibration with the rotor itself. It becomes.
In addition, as the size of the commutator decreases, the area of the printed wiring board decreases, and it becomes difficult to secure a space for the wiring pattern, and it becomes difficult to secure a hole for inserting the coil positioning guide.
In addition, since the eccentric weight must be as large as possible to secure the vibration amount, the density of parts arranged on the printed wiring board increases, and it becomes difficult to arrange an injection molding gate between these parts. Was.
Therefore, the present invention proposes a mold-type eccentric rotor that allows the air-core armature coil to be mounted at a predetermined position when mounting the air-core armature coil on the printed wiring board and that can be injection-molded from the printed wiring board side. The purpose of the present invention is to make the motor thinner by combining it with an eccentric rotor. Another object of the present invention is to further reduce the thickness of the vibration motor by improving the brush base and the bracket.
[0008]
[Means for Solving the Problems]
A basic solution to the above-mentioned problem is that, as in the first aspect of the present invention, a shaft insertion hole is provided at the center of rotation, and an air-core armature coil mounting area is eccentric to the outside in the radial direction. A printed wiring having a commutator portion formed of a plurality of commutator segments formed radially outward of the shaft insertion hole on the surface, a recess for a gate opening formed on an outer peripheral portion, and a terminal connection pattern formed thereon. A board, a plurality of air-core armature coils disposed in an air-core armature coil mounting area on the second surface of the printed wiring board, and an eccentric located on a side opposite to the air-core armature coil via a center. The weight and the air-core armature coil can be achieved by a molded eccentric rotor integrally formed of resin from the first surface side through the recess.
In this way, the printed wiring board can be injection-molded from the printed wiring board side at the outer peripheral gate opening recess without providing a hole for the air-core armature coil placement guide, and the eccentric weight is integrated with the air-core armature coil. Can be molded.
[0009]
According to the invention of the present application, the sintered oil-impregnated bearing can be integrally formed as in the invention described in claim 2, and the rotation accuracy of the mold-type eccentric rotor can be further increased.
Further, by providing a continuous belt-like convex portion or discontinuous convex portion on the outer periphery of the cylindrical bearing as in the invention of claim 3, the bonding strength between the bearing and the resin can be increased, and furthermore, the convex portion can be used. The printed wiring board can be supported.
It is preferable that the resin is made of a lightweight resin having a density of 2 or less, and the printed wiring board has an eccentric weight portion removed.
By doing so, the density of the air-core armature coil can be reduced to 4 or less from the density and space factor of the resin and the copper wire. Will move. Further, since the eccentric weight can be made thicker by the thickness of the printed wiring board, the amount of vibration can be increased.
[0010]
Also, as in the invention as set forth in claim 5, it is preferable that the recess for the gate opening is formed between the plurality of air-core armature coils on the outer periphery of the printed wiring board.
This makes it possible to improve the flow of the resin, which is advantageous for a small-diameter eccentric rotor.
Further, in order to manufacture the molded eccentric rotor, the first and second surfaces are provided as in the invention as set forth in claim 6, the shaft insertion hole is provided at the center, and the air-core A printed wiring board having a commutator portion including a plurality of commutator segments formed radially outward of the shaft insertion hole on the first surface and having an armature coil mounting area; and an air-core armature coil. Is mounted on an injection molding die using a guide so that the printed wiring board is on the gate side, an eccentric weight is arranged using a positioning guide, and the printing is performed outside the mounting portion of the air-core armature coil. It is preferable that the wiring board be formed by injection molding from the first surface side at the gate opening recess formed in the outer peripheral portion.
According to such a manufacturing method, even an air-core armature coil having a small inner diameter can be mounted on a printed wiring board, and can be easily integrated with an eccentric weight.
[0011]
As shown in claims 7 and 8, the mold eccentric rotor according to any one of claims 1 to 5, a shaft for supporting the eccentric rotor, a housing for supporting the shaft, and the eccentric rotor. A magnet is provided on a part of the housing so as to face the rotor via a gap, and a brush is provided on a brush base at the inner diameter of the magnet, and a part of the brush base passes below the magnet. Or at least one end of the shaft is fixed to the housing, and a bracket is attached to an opening of a case forming the housing, and the housing has a thickness. The brush base is flexible and has a thickness including an adhesive layer of 0.18 mm or less. Managing the through hole is provided in a part of the portion magnet is disposed, a portion of the brush base through the hole can be achieved with what is derived as a feeding electrode on the housing side.
In this way, a flat-type motor can be easily obtained, and even if the thickness of the bracket is 0.2 mm or less, the brush-based deriving means by the through-hole processing can be used without employing any unreasonable means such as pressing. Since the brush base can be easily formed and the flexible brush base is generally about 0.15, it can be easily led out to the side circumference of the motor through the through-hole, so that there is no fear of increasing the thickness. At this time, since the brush base is pressed by the through hole and the magnet, even if a downward force is applied to the brush sliding portion in the drawing, the brush base of the brush fixing portion can be prevented from floating.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, drawings of an embodiment of the present invention will be described.
FIG. 1 is a view of the molded eccentric rotor R of the present invention as viewed from the lower surface R1 side.
FIG. 2 is a diagram of the molded eccentric rotor R viewed from the upper surface R2 side.
FIG. 3 is a first assembly view of the molded eccentric rotor.
FIG. 4 is a second assembly drawing.
FIG. 5 is a sectional view of an axial gap type coreless motor including the rotor.
FIG. 6 is a sectional view of an axial gap type coreless motor provided with the rotor, showing an embodiment in which a sintered oil-impregnated bearing is not used.
[0013]
Hereinafter, embodiments of the present application based on the above drawings will be described.
1 and 2 are plan views of the eccentric rotor R molded into a disk shape. FIG. 1 is a diagram of a lower surface R1 viewed from a first surface 1a side of a printed wiring board described later, and FIG. 2 is a diagram of an upper surface R2 viewed from the air core armature coil side described later on the back side of FIG.
The eccentric rotor R has an eccentric weight 3 having a printed wiring board 1 on one lower surface R1, one end of a sintered oil-impregnated bearing J, and a positioning guide hole 3b, and air core armature coils 2A, 2B, 2C on an upper surface R2. The other ends of the weight 3 and the sintered oil-impregnated bearing J are exposed as shown by solid lines, and a resin 4 is formed by injection molding in other portions so as to fill the gaps therebetween.
[0014]
The printed wiring board 1 is formed in a substantially half-moon shape so that the three air-core armature coils 2A, 2B and 2C are placed on one side of the disk on the second surface 1b on the upper surface R2 side. A shaft insertion hole 1c is provided at the center of rotation, and a first surface 1a on the lower surface R1 side around the shaft insertion hole 1c is provided with a commutator portion 1s composed of a plurality of commutator segments. 1c.
In addition to the above, the printed wiring board 1 is provided with a terminal connection pattern for connecting winding ends of the air-core armature coils 2A, 2B, 2C to each segment pattern, a spark-prevention print resistor, or a print coil as required. Are not shown.
[0015]
As shown in FIG. 2, the air-core armature coils 2A, 2B, and 2C are mounted on the mounting area 1d provided on the second surface 1b of the printed wiring board 1 at an arrangement angle of 80 degrees. Further, since the commutator portion S surrounds the shaft insertion hole 1c, the printed wiring board 1 is formed in a half-moon shape having a portion protruding from a line including the rotation center of the disk.
The air-core armature coils 2A, 2B, and 2C are formed by windings, have a predetermined thickness, have an opening angle of a conductor of 60 degrees, and have a winding shaft-shaped space at the center. In order to reduce the outer shape of the coil, the space inside the coil is also small.
[0016]
The eccentric weight 3 is formed in an arc shape having a predetermined width and thickness. The width of the eccentric weight 3 is within a range not protruding from the disk diameter of the eccentric rotor R. The thickness of the eccentric weight 3 is equal to that of the air-core armature coils 2A, 2B, 2C and the printed wiring board 1. The combined thickness is such that the outer shape and thickness of the eccentric rotor R do not affect downsizing.
The eccentric weight 3 is provided with two positioning guide holes 3b for determining the position of the eccentric weight 3 at the time of molding the eccentric rotor R so as to penetrate in the thickness direction. 3a is formed.
Further, a concave portion 3e is provided in the eccentric weight 3, and a gate necessary for injection molding is disposed in the concave portion 3e, and the flow of the resin is further improved by the concave portion 3e.
The eccentric weight is made of a copper-tungsten alloy, and a density (specific gravity) of 15 to 18.4 is selected in consideration of current consumption and centrifugal force in response to a motor size, for example, a diameter of 14 mm to 10 mm.
[0017]
A recess (1e) for a gate opening is formed in the outer peripheral portion of the printed wiring board 1. This is achieved by disposing a notch on the outer periphery of the printed wiring board 1 and injecting the resin 4 therefrom at the time of injection molding, so that the resin can be injected from the printed wiring board 1 side. This is because it is not necessary to form an opening in the opening. The gate opening recess 1e is provided between the air-core armature coils 2A and 2B and between 2B and 2C.
In the present embodiment, the shape is a semicircle, but a square or an ellipse can be considered, and the shape is not particularly limited to a semicircle.
[0018]
The sintered oil-impregnated bearing J is provided in the cylindrical insertion hole 1c of the printed wiring board 1 in a cylindrical shape, and rotatably supports the eccentric rotor R to the bracket 7 by a shaft 8 described later. Further, a convex portion Ja is provided on the circumference at the central portion in the cylindrical axis direction.
After the molding, the sintered oil-impregnated bearing J can increase the strength of the eccentric rotor R with respect to the axial direction due to the protrusion Ja.
The same effect can be obtained even if the convex portion Ja is formed intermittently over the entire outer periphery of the cylindrical sintered oil-impregnated bearing J, and the mounting strength in the rotational direction can be increased.
The eccentric rotor R is formed by integrally molding the printed wiring board 1, the air-core armature coils 2A, 2B, 2C, the eccentric weight 3, and the sintered oil-impregnated bearing J into a resin 4.
The resin 4 has a low density (specific gravity) so that the position of the center of gravity is not offset as much as possible, and has a density of 2 or less such as polybutylene terephthalate resin having good moldability and reproducibility. Some 1.4 items are selected.
[0019]
A method of manufacturing such an eccentric rotor R will be described with reference to FIGS. FIG. 3 shows a preparation operation using a jig, and FIG. 4 shows a molding operation using an injection mold.
The preparation operation will be described with reference to FIG.
The jig 5 on which the air-core armature coils 2A, 2B, and 2C are mounted on the printed wiring board 1 is provided with arrangement guides 5A, 5B, and 5C that match the winding axis dimensions of the air-core armature coils 2A, 2B, and 2C. I have. The arrangement guides 5A, 5B and 5C are formed so as to protrude from the upper surface of the jig within the thickness of the air-core armature coils 2A, 2B and 2C at an arrangement open angle of 80 degrees.
Further, on the upper surface of the jig, positioning pins 5F, 5F into which semi-circular recesses 1e formed on the outer periphery of the printed wiring board 1 enter, and pins 5D at positions of the shaft insertion holes 1c of the printed wiring board 1.
The assembling method in the preparation work is as follows.
First, the air-core armature coils 2A, 2B, and 2C are fitted into the arrangement guides 5A, 5B, and 5C of the jig 5, and an adhesive (here, an anaerobic ultraviolet curing type) is attached to the surface above each of the air-core armature coils 2A, 2B, and 2C. ) Is applied.
Next, the printed wiring board 1 is covered with the shaft insertion hole 1c and the pin 5D, the recess 1e for the gate opening and the positioning pin (5F, 5F) are respectively aligned, and slightly pressed and temporarily adhered to the printed wiring board 1 before injection molding. Do the preparation work of 1.
[0020]
Thereafter, predetermined terminals of the air-core armature coils (2A, 2B and 2C) are connected to terminal connection patterns provided on the printed wiring board 1 by soldering or heat welding.
The connection portion is coated with an ultraviolet-curable adhesive, and then irradiated with ultraviolet light together with the ultraviolet-curable adhesive applied to the coil, thereby protecting the connection portion and fixing the coil to the printed wiring board.
[0021]
Next, the molding will be described with reference to FIG.
In the lower mold 55 for injection molding, placement guides 55A, 55B, and 55C for injection molding are formed in the recesses forming the disk by molding to the same size as the placement guides 5A, 5B, and 5C for the jig 5, and further, The guide pins 5E and 5E which enter the positioning guide hole 3b of the eccentric weight 3 at the position are raised. Then, a bearing mounting pin 5G for mounting the sintered oil-impregnated bearing J is set up at the center.
[0022]
The injection molding upper die 56 is provided with a printed wiring board gate opening 56e at a position corresponding to the printed wiring board gate recess 1e, and an eccentric weight at a position corresponding to the eccentric weight gate opening recess 3e as necessary. A gate port 56c is provided.
The gate openings 56e and 56c are configured to fit within the recesses if the gate recesses 1e and 3e can be made large. When the size of the gate recesses 1e, 3e is limited, a so-called half gate may be used so that the openings of the gate openings 56e, 56c cover the parting surface of the lower injection mold 55.
Further, the periphery of the gate may be formed so as to be concave in the thickness direction within a range in which the resin 4 after molding is contained in the recesses 1e and 3e for the gate opening. This is because even when a pin gate or the like is cut off, a trace of processing is formed in a very small convex shape at the time of separation, so that the processing trace can be prevented from protruding from the first surface of the eccentric rotor R.
If there is room in the radial direction, a gate may be provided on the side surface of the gate recesses 1e, 3e, and injection molding may be performed as a side gate.
[0023]
A molding process using the lower mold 55 for injection molding and the upper mold 56 for injection molding will be described.
First, the sintered oil-impregnated bearing J is loaded on the bearing insertion pin 5G, and the printed wiring board 1 on which the air-core armature coils 2A, 2B, and 2C are mounted is placed on the air-core armature with the board surface facing upward. The space in the shape of the winding shaft of the coil is loaded according to the arrangement guides 55A, 55B and 55C for injection molding. Further, the eccentric weight 3 is mounted on the lower mold 55 for injection molding in accordance with the guide pins 5E and 5E.
Next, the upper mold 56 for injection molding is lowered, and the resin 4 is injected from the position of the semicircular recess 1e and the position of the eccentric weight gate port 56c to complete the mold eccentric rotor (R).
[0024]
Although the above-described manufacturing method has been described as using the preparatory work step, the preparatory work step shown in FIG. 3 can be omitted if the eccentric weight 3 is used for positioning the printed wiring board 1.
That is, since the eccentric weight 3 has a thickness including the printed wiring board 1, the eccentric weight 3 is positioned at the printed wiring board 1 by making the inner peripheral shape the same as the outer shape of the printed wiring board 1. It can be used as a member.
[0025]
As described above, since the gate opening recess 1e provided on the outer peripheral portion of the printed wiring board 1 is provided, a gate is provided on the second upper surface side of the eccentric rotor and injection molding is performed. What has been done becomes possible from the first surface 1a side of the printed wiring board 1, which is the lower surface.
Further, it is not necessary to provide a hole for inserting a guide pin for positioning the air-core armature coil in the printed wiring board, so that the degree of freedom in printing is increased.
Further, since the recess for the gate opening is provided between the air-core armature coils, the resin flows between the coils to improve the resin circulation.
By providing the eccentric weight with a channel 3a on the outer peripheral portion or the like, the resin circling is improved, and the eccentric weight has strength in the axial direction and can be integrated with the printed wiring board 1 and the air-core armature coil. The printed wiring board 1 does not need to be formed, and the thickness of the printed wiring board can be made an eccentric weight, so that the amount of eccentricity can be increased.
[0026]
FIG. 5 shows an ultra-thin coreless vibration motor employing the above-described molded eccentric rotor and having a thickness of about 2 mm.
In this vibration motor, a housing H is constituted by a case 6 formed by drawing a thin magnetic stainless steel plate of 0.15 mm and a bracket 7 of about 0.15 mm attached to an opening of the case.
Inside, a shaft 8 having a thickness of about 0.5 mm is press-fitted and fixed at the center of the bracket 7, and a thin ring-shaped magnet 9 is placed radially outward of the shaft 8.
Here, the base end 8a of the shaft 8 may be laser-welded instead of press-fitting.
A molded eccentric rotor R having a thickness of about 0.65 mm is rotatably mounted on the shaft 8 and faces the ring-shaped magnet 9 through an axial gap.
[0027]
The molded eccentric rotor R is composed of three armature coils and one eccentric weight as described above, and receives electric power from the pair of brushes 10 and 11 via the commutator portion 1s. Here, the eccentric rotor R is represented by a sectional view taken along the line AA in FIG.
The bracket 7 has a through hole 7a at a part of the position of the magnet 9, and the bases of the brushes 10 and 11 are implanted on a flexible base 12 by soldering or heat welding, so that a power supply lead portion 12a is formed. It extends in the radial direction and is led out to the side periphery of the case 6 through the through hole 7a as the power supply electrode portion 12b.
Therefore, when the flexible base 12 is led out from the space between the magnet 9 and the bracket 7, a space for leading out the flexible base 12 having a thickness of about 0.15 can be easily secured.
[0028]
Here, the flexible base 12 has a predetermined surface to which an adhesive is adhered, and is preferably fixed to the bracket 7 and the magnet 9 by adhesion.
The power supply electrode portion 12b of the flexible base 12 is folded back at the portion of the tongue piece 7b protruding from the bracket 7, so that the solder electrodes are exposed in three directions so that it can be easily soldered to the printed wiring board on the device side. I have.
[0029]
On the other hand, a case 6 constituting the other part of the housing is provided with a burring-shaped through hole 6a in the center of which the other end of the thin stainless steel shaft 8 is mounted, and a polyimide film P is provided around the through hole 6a. Distribute. The mold type eccentric rotor R is slidably contacted with the polyimide film P by the pressing force of the pair of brushes 10 and 11 via the bearing J.
For this reason, the eccentric rotor R is always urged toward the case 6 and is rotatably pressed by the polyimide film P. Therefore, there is no possibility that the eccentric rotor R moves further toward the case 6 and hits the same, and the gap with the case 6 is always constant. Thus, the rotation can be stably supported without variation in the rotation position.
[0030]
Here, the other end of the shaft 8 is laser-welded to the case at the burring-shaped through hole 6a.
Therefore, there is no possibility that the shaft 8 will fall out of the through hole even when an impact such as a drop is applied.
In the above-described embodiment, an example in which three air-core armature coils are used has been described. However, a configuration in which two coils are used to increase the eccentric weight is also possible.
[0031]
FIG. 6 shows a vibration motor using an eccentric rotor according to another embodiment of the present invention.
This vibration motor is an example in which a bearing portion is formed of resin 4 without providing a sintered oil-impregnated bearing on the eccentric rotor R. By integrally forming the bearing portion with the resin 4, the number of components can be reduced, and component costs and work costs can be reduced.
In the case of this configuration, a recess for forming this bearing portion may be provided in the injection mold.
Further, in this embodiment, a so-called fixed shaft type motor in which a bearing portion is provided on the eccentric rotor R has been described, but a shaft rotating type motor in which a shaft is integrally formed with the eccentric rotor R may be used.
In this case, a hole for mounting a rotating shaft may be provided in the resin molding die.
[0032]
Although the mold type eccentric rotor, the manufacturing method of the rotor, and the axial gap type coreless vibration motor including the rotor have been described in the embodiments of the present application, the printed wiring board 1 is configured to be circular and the eccentric weight 3 is not used. It is also possible to provide a conventional molded rotor, a method of manufacturing the rotor, and an axial gap type coreless motor including the rotor.
[0033]
That is, the printed wiring board 1 is formed in a circular shape, and the plurality of air-core armature coils 2A, 2B, and 2C are evenly arranged. (When the number of coils is three, the arrangement angle is 120 degrees)
By providing a recess for the gate opening so as to be located between the coils, resin is injected from the printed wiring board side and injection molded, and the printed wiring board 1 and the air-core armature coils 2A, 2B, 2C and the sintered oil-impregnated bearing are provided. J can be formed integrally.
Also in this case, instead of the sintered oil-impregnated bearing J, a shaft can be used as a normal motor by integrating the shaft into a shaft rotation type motor and projecting the shaft to the outside of the motor case to form an output shaft.
Further, if a gear is provided on the outer periphery of the rotor and the gear is exposed to the outside of the motor case and is used for output means, the rotor can be constituted by a fixed shaft type rotor.
The manufacturing method in FIGS. 3 and 4 is common except for the position of the eccentric weight and each guide, and the operation and effect are also common.
[0034]
【The invention's effect】
Since the present invention is configured as described above, when mounting the air-core armature coil on the printed wiring board, the printed wiring board is small, and it is possible to provide a hole for the air-core armature coil guide on the printed wiring board side. A mold-type eccentric rotor that can be easily mounted even if it is not possible and can be injection-molded from the printed wiring board side. it can.
[0035]
According to the first aspect of the present invention, the printed wiring board, the eccentric weight, and the eccentric weight can be formed by injection-molding the printed wiring board from the printed wiring board side in the outer peripheral gate opening recess without providing a hole for the air-core armature coil placement guide in the printed wiring board. The air-core armature coil can be integrally formed together.
According to the second aspect of the present invention, the air-core armature coil side can have a substantial density of 4 or less from the density and space factor of the resin and the copper wire. Will move.
[0036]
According to the fifth aspect of the invention, the flow of the resin is improved, which is advantageous for an eccentric rotor having a small diameter.
According to the sixth aspect of the present invention, the air-core armature coil, the printed wiring board, and the eccentric weight can be easily integrated.
[0037]
According to the seventh and eighth aspects of the present invention, even if the thickness of the bracket is set to 0.2 mm or less, the brush-based deriving means can be easily formed by the through-hole processing without employing an unreasonable means such as pressing. Since the flexible brush base is usually about 0.15 mm, it can be easily led out to the side circumference of the motor through the through hole, so that there is no fear of increasing the thickness. At this time, since the brush base is pressed by the through hole and the magnet, an axial gap type motor is obtained in which the brush base of the brush fixing portion can be prevented from floating even when a downward force is applied in the drawing of the brush sliding portion. .
[Brief description of the drawings]
FIG. 1 is a diagram of a molded eccentric rotor R of the present invention as viewed from an upper surface side R1.
FIG. 2 is a view seen from a lower surface side R2 of a mold type eccentric rotor R.
FIG. 3 is a first assembly view of the molded eccentric rotor of FIG. 1;
FIG. 4 is a second assembly view of FIG.
FIG. 5 is a cross-sectional view of an axial gap type coreless motor including the rotor cut along the line AA in FIG. 1;
FIG. 6 is a sectional view of an axial gap type coreless motor including the rotor, showing an embodiment in which a sintered oil-impregnated bearing is not used.
[Explanation of symbols]
1 Printed wiring board
2A, 2B and 2C air core armature coils
3 Eccentric weight
4 resin
5 jigs
J sintered oil-impregnated bearing
6 cases
7 Bracket
H housing
8 axes
9 magnets
10, 11 A pair of brushes
12 Flexible base

Claims

A shaft insertion hole is provided at the center of rotation, and there is an air-core armature coil mounting area eccentric radially outward, and a plurality of commutator segments radially outward of the shaft insertion hole on the first surface. A printed wiring board on which a commutator portion made of the following is formed, a recess for a gate opening is formed on an outer peripheral portion, and a terminal connection pattern is further formed, and an air-core armature coil mounting on the second surface of the printed wiring board is provided. A plurality of air-core armature coils disposed in the mounting area, and an eccentric weight located on the opposite side of the air-core armature coil via the center of rotation, the air-core armature coil together with the first surface via the recess. Molded eccentric rotor integrally molded with resin from the side.

2. The mold type eccentric motor according to claim 1, wherein a cylindrical sintered oil-impregnated bearing is integrally formed with the resin at the rotation center.

3. The mold type eccentric rotor according to claim 2, wherein a convex portion is provided continuously or intermittently over the entire outer periphery of the cylindrical shape of the bearing.

The mold eccentric rotor according to claim 1, wherein the resin is made of a lightweight resin having a density of 2 or less, and the printed wiring board has an eccentric weight portion removed.

The mold eccentric rotor according to claim 1, wherein the gate port recess is formed between the plurality of air-core armature coils on an outer periphery of the printed wiring board.

There are first and second surfaces, a shaft insertion hole is provided at the center, and an air-core armature coil mounting area is located radially outward of the shaft insertion hole. The printed wiring board and the air-core armature coil formed with a commutator portion composed of a plurality of commutator segments formed in the mold are injected into an injection mold using a guide so that the printed wiring board is on the gate side. The eccentric weight is mounted using a positioning guide, and the resin is applied from the first surface side at a gate opening recess formed on the outer peripheral portion of the printed wiring board outside the mounting portion of the air-core armature coil. For manufacturing a mold-type eccentric rotor obtained by injecting and injection molding.

A mold-type eccentric rotor according to any one of claims 1 to 5, a shaft supporting the eccentric rotor, a housing supporting the shaft, and a housing that faces the eccentric rotor via a gap. A shaft provided with a magnet disposed on a part thereof and a brush disposed on a brush base at an inner diameter of the magnet, and a part of the brush base being led out as a power supply electrode to a side of the housing through a lower side of the magnet. Directional air gap type coreless vibration motor.

At least one end of the shaft is fixed to the housing, a bracket is attached to an opening of a case forming the housing, the housing has a thickness of 0.2 mm or less, and the brush base is flexible. The thickness of the housing including the adhesive layer is 0.18 mm or less, and the housing is provided with a through hole in a part of a portion where a magnet is arranged, and a part of the brush base passes through the through hole so that a portion of the brush base is on a side of the housing. The axial gap type coreless vibration motor according to claim 5, wherein the coreless vibration motor is led out as a power supply electrode.