JP3606850B2

JP3606850B2 - Vibration motor

Info

Publication number: JP3606850B2
Application number: JP2002135458A
Authority: JP
Inventors: 啓介浅場
Original assignee: 株式会社アサバ
Priority date: 2002-05-10
Filing date: 2002-05-10
Publication date: 2005-01-05
Anticipated expiration: 2022-05-10
Also published as: JP2003333796A; CN1458731A; KR20030087988A

Description

【０００１】
【発明の属する技術分野】
本発明は偏心分銅を備え、携帯電話やＰＨＳ（ＰｅｒｓｏｎａｌＨａｎｄｙｐｈｏｎｅＳｙｓｔｅｍ）等の小型電話機のバイブレータ呼び出し用として好適な小型の振動モータに関する。
【０００２】
【従来の技術とその問題点】
偏心分銅を備える振動モータには従来から各種の構造のものがある。
近年、携帯電話やＰＨＳ等の小型電話機において、着信音を鳴らさずに着信を知らせる手段として、電話機内に小型の振動モータを設け、着信音を鳴らす代わりにこの振動モータを駆動せしめて電話機自体を振動させ、この振動により使用者に着信を知らせるようにしたものがあり、このような電話機の機能は「バイブレーション機能」として殆ど全ての小型電話機に搭載されている。
【０００３】
上述した用途に従来から一般的に使用されている振動モータには、図９に示すようなものがあり、モータ本体３１から外部へ導出された回転軸３２の先端に、偏心分銅３３が取り付けられている。
【０００４】
このような振動モータは、近年より一層の小型化が進む携帯電話等の内部に収納されるので、モータ本体３１は直径が６ｍｍ程度、長さが１２ｍｍ程度の極めて小型のものが使用され、回転軸３２は直径が０．７ｍｍ程度、偏心分銅３３には重さ０．５〜０．７ｇ程度のものが一般的に使用されている。
【０００５】
しかし、上述した従来の振動モータでは偏心分銅３３がモータ本体３１の外部に設けられているので、偏心分銅が電話機内部における電子回路等の他の構成部材に接触しないように、これらの構成部材とは充分な間隔をあけて取り付ける必要があるので、取付位置の自由度が低いという問題がある。
【０００６】
また、小型電話機に使用される偏心モータには上述したように小型であることのほかに、落下衝撃に対する充分な強度も要求される。
【０００７】
しかし上述した従来のものでは、直径が０．７ｍｍ程度の細い回転軸３２の先端に偏心分銅３３が設けられているので、回転軸３２に対してラジアル方向の衝撃が加わるとモータ本体３１から導出されている部分の基部に衝撃による力が集中してこの部分で折れ曲がり易く、電話機内の周囲の部材に対して偏心分銅が接触して回転できなくなるという不具合が生じる。
【０００８】
特に、振動量（振動の強さ）を大ならしめることを目的として偏心分銅の偏心量や重量を大ならしめると、落下時において回転軸に掛かる力はより大となり、落下衝撃に対する強度は低下する。
【０００９】
振動モータは、上述した小型電話機用以外にも、工業用試験機器等の測定機械器具において所定の振動を発生させたり、ゲーム機等における仮想現実体験用の振動発生源として用いたり、あるいは小型あんま機のマッサージ振動発生源として用いられ、これらのような使用目的においても上述した小型電話機用の振動モータと同様に耐衝撃性の向上およびより一層の小型化が求められている。
【００１０】
【目的】
本発明の目的とするところは、充分な振動量を得ることができ、しかも小型電話機等の被組み付け機器に対する取付スペースの自由度が高く、かつ衝撃に対する充分な強度を有する振動モータを提供することにある。
【００１１】
【本発明の構成】
上記目的を達成するために、本発明の請求項１に係る振動モータは、頂板は有するが下部が開口する円筒状ハウジングがベース上に固定され、ハウジングの頂板に、ラジアル方向に着磁されたリング状のマグネットを外周に備えるステータヨークの上端部が固定され、このステータヨークの中央にあけた縦孔内に上端部が嵌入固定された固定軸の下端がベースに固定され、下部が整流子を兼ねる円筒部と、この円筒部から外側に向かうフランジ部と、このフランジ部の外周辺部から上方へ突出する複数の支持突起とよりなる支持体に、内側面が前記マグネットの外周面に対峙する複数の極歯をリング状の本体部の内側に有し、各極歯の脚部まわりにコイルが捲装され、外周辺部に偏心分銅が取り付けられたコアの隣り合う極歯間に前記支持体の支持突起を嵌入してコアを取り付け、前記支持体の下部における整流子がベース上に設けられたブラシと接触するように支持体を固定軸まわりに回転可能に設けたものとしてある。
【００１２】
本発明の請求項２に係る振動モータは、前記ステータヨークが、下部が開口する円筒状に形成され、前記支持体の円筒部の上部をステータヨーク内に臨ませてたものとしてある。
【００１３】
本発明の請求項３に係る振動モータは、前記固定軸の下端が、上部に外周フランジを有する円柱状の座台の上面に形成した中央凹部に嵌入固定され、この座台の下部が、ベースにあけられ、座台の下部の外径よりも内径の大なる中央孔内に臨むようにして座台がベースに固定されたものとしてある。
【００１４】
本発明の請求項４に係る振動モータは、前記支持体における円筒部の内面に、上下の部分よりもわずかに内径の大なる大内径部を形成して固定軸と円筒部との間にオイル溜めを設けたものとしてある。
【００１５】
本発明の請求項５に係る振動モータは、前記マグネットの重心を通る水平面が、前記コアの重心を通る水平面よりも上方に位置し、コアがマグネットの磁力によって常に上方へ吸引されるようにしたものとしてある。
【００１６】
本発明の請求項６に係る振動モータは、頂板は有するが下部が開口する円筒状ハウジングがベース上に固定され、ハウジングの頂板に、上部は閉じているが下部が開口し、ラジアル方向に着磁されたリング状のマグネットを外周に備えるステータヨークの上端部が固定され、このステータヨーク内に円筒状の軸受スリーブが嵌入固定され、下部が整流子を兼ねる円筒部と、この円筒部から外側に向かうフランジ部と、このフランジ部の外周辺部から上方へ突出する複数の支持突起とよりなる支持体を回転軸まわりに固定し、内側面が前記マグネットの外周面に対峙する複数の極歯をリング状の本体部の内側に有し、各極歯の脚部まわりにコイルが捲装され、外周辺部に偏心分銅が取り付けられたコアの隣り合う極歯間に前記支持体の支持突起を嵌入してコアを支持体に取り付け、前記支持体の下部における整流子がベース上に設けられたブラシと接触するように前記回転軸の上部を前記軸受スリーブ内に回転可能に取り付けたものとしてある。
【００１７】
本発明の請求項７に係る振動モータは、前記軸受スリーブの内面に、動圧溝を形成したものとしてある。
【００１８】
本発明の請求項８に係る振動モータは、前記偏心分銅を、少なくともその一部分が前記コアのリング状本体部の上下面と重なるようにコアに取り付けたものとしてある。
【００１９】
本発明に係る振動モータの実施態様の第１は、前記ハウジングを若干弾性を有する素材、厚さのもので構成し、外部からの衝撃を受けると弾性変形して分銅の上端面に接触し、分銅に掛かる衝撃がハウジングに分散されて衝撃が緩和されるようにした構成のものとしてある。
【００２０】
また、実施態様の第２は、上記ハウジングを厚さ０．１０〜０．１５ｍｍのステンレス鋼よりなるものとしてある。
【００２１】
さらに実施態様の第３は、前記支持体の円筒部下端とベース上面との間の隙間αと、分銅の下面とベース上面との間の隙間βをほぼ同じ寸法に設定し、分銅にスラスト方向の衝撃が加わると、分銅の下端面と支持体の下端面がほぼ同時にベース上面に接触して衝撃が分散されるように構成したものとしてある。
【００２２】
【実施例】
以下、本発明に係る振動モータの実施例を添付図面に示す具体例に基づいて詳細に説明する。
図中の符号１はベース、２はハウジングを示し、下部開口の円筒状に形成されたハウジング２の頂板２ａの中央にあけた孔２ｂ内にステータヨーク３の上端部が加締め固定されている。
【００２３】
上記ステータヨーク３は下部が開口する円筒状に形成されていて、頂部中央にあけた縦孔３ａ内に固定軸４の上端部が圧入や接着等により固定され、またステータヨークの外周にリング状のマグネット５を取り付けてあり、このマグネットはラジアル方向に着磁されている。
【００２４】
前記固定軸４の下端には座台６を設けてあり、この座台は上面に形成された中央凹部６ａに固定軸の下端が嵌入固定され、外周フランジ６ｂの下面が前記ベースの中央孔１ａの上部内周面に形成された段差部１ｂの上面にて支持され、この段差部へ接着剤にて固定されている。
【００２５】
なお、座台６は段差部への接着前においては水平方向に移動できるよう座台下部６ｃ外周面とベースの中央孔１ａ内周面との間に適宜の遊びを設けてあり、固定軸４の芯合わせを行なってから座台を段差部へ接着等の手段によって固定することにより、固定軸をベースに対して正確に垂設できるように構成してある。
【００２６】
しかして、前記固定軸４のステータヨーク３と座台６との間における外周には支持体７を固定軸まわりに回転可能に設けてあって、支持体の円筒部７ａ上部をステータヨーク３内に臨ませてあり、支持体は円筒部７ａの軸線方向中央部の外周にフランジ部７ｂを有し、このフランジ部の外周辺部に上方へ突出する複数の支持突起７ｃ、７ｃが形成されていて、上記円筒部、フランジ部および支持突起を、例えばポリフェニレンサルファイド等の合成樹脂材により同一材で一体に形成してある。
【００２７】
前記円筒部７ａ内面における軸線方向の中央部には、同円筒部内面の上下の部分よりも若干内径の大なる大内径部７ｄを形成してあり、この大内径部は固定軸４との間におけるオイル溜めとして機能し、固定軸４に対する支持体７の回転をより円滑ならしめるようにしてある。
【００２８】
上記支持体７はコア８の内周辺部を支持しており、このコアはリング状のコア本体部８ａの内側から内方に突出し、内側面が前記マグネット５の外周面に対峙する極歯８ｂ、８ｂを有している。
【００２９】
また、前記支持体７の支持突起７ｃ、７ｃはコア８の隣り合う極歯８ｂ、８ｂ間とコア本体部８ａ内周面との間に嵌入され、この支持突起によって支持体に対するコアの位置合わせがなされ、かつ前記フランジ部とともにコアを支持するようになっている。
【００３０】
コア８は、例えば珪素鋼板よりなり、少なくとも上下面および極歯の脚部まわりに、例えばポリブチレンテレフタレート等の合成樹脂材よりなる保護部材９をモールド成型により設けてあり、各極歯８ｂの脚部まわりにコイル１０を捲装してあって、コイルの巻線がコアに直接接触しないように構成してある。
【００３１】
上記コイル１０の巻線端部は、支持体７の円筒部７ａ下部に設けた整流子１１に接続されており、この整流子はベース１上に設けたブラシ１２と接触するように設けられている。
【００３２】
また、前記コア８の外周辺部には、偏心錘たる瓦状の分銅１３を取り付けてあり、この分銅は例えばタングステンよりなり、内周面の長手方向に形成した溝１３ａをコアの外周辺部に嵌合せしめて接着剤等で固定してある。このように分銅に溝を設けてコアに嵌合せしめると、分銅は溝の深さ分コアの上下面に重なり、したがって溝のない分銅をコアの外周縁に取り付ける場合に比して分銅の回転半径を小ならしめることができ、振動モータの小型化を図ることができる。
【００３３】
上記コア８は、軸線方向において前記マグネット５よりも下方に位置せしめてあって、より詳しくは前記マグネット５の重心を通る水平面ＭＰをコアの重心を通る水平面ＣＰよりも上方に位置せしめてあり、コアはマグネットの磁力によって常に上方に吸引された状態となるようにしてある。
【００３４】
したがって、支持体は円筒部７ａ上端がランナー１４に当接させられ、円筒部下端と座台との間に隙間があいた状態で回転し、通常の使用状態においては円筒部下端が座台上面に接触することがなく、これら円筒部下端と座台上面との接触に起因する損傷や磨耗のおそれがまずなく、長寿命の振動モータを実現できるというメリットがある。
【００３５】
なお、図中の符号１４は円筒部７ａの上端面とステータヨーク３の頂部内面との間に介在せしめた底摩擦係数の合成樹脂材よりなるリング状のランナー、１５はブラシ１２と接続され、ハウジング２外に導出された端子を示す。
【００３６】
上述のように構成した本発明の振動モータは、端子１５に駆動用の電流を供給すると、ブラシ１２および整流子１１を経てコイル１０に通電され、コア８の極歯に生じる磁力とマグネット５との間の磁気的吸引・反発力によってコアが支持体７および分銅１３とともに固定軸４まわりに回転駆動され、分銅１３の偏心回転に伴って振動が発生する。
【００３７】
落下等によって振動モータが衝撃を受けた場合、固定軸４は軸長が短く、かつステータヨーク３と座台６にて両端が支持されていて、両端支持部の間に支持体７を設けてあるので、衝撃力が回転軸の一部に集中して回転軸を破損するようなおそれはまずない。
【００３８】
また、支持体７はその円筒部７ａの上部がステータヨーク３の開口下部から内部に臨んでいて、支持体と回転軸との軸線方向における接触長さを大ならしめてあるので、支持体から回転軸に掛かる力が充分に分散され、しかも分銅の重心を通る水平面が支持体の円筒部７ａの上部を通るので、落下衝撃により分銅に掛かる力のラジアル方向成分が円筒部の上部に掛かり、支持体のねじれが生じにくく、したがってラジアル方向の衝撃力に対する強度が大である。
【００３９】
さらに本実施例の振動モータにおいては、支持体７の円筒部下端面と座台６の上端面との間の隙間αと、分銅１３の下端面とベース１の上端面との間の隙間βの寸法をほぼ同じとしてあり、落下衝撃力のスラスト方向成分によって分銅１３および支持体７が下方に移動した場合には分銅の下端面と支持体の下端面がほぼ同時にベース１の上面に接触して衝撃が分散されるようにしてある。
【００４０】
なお、モータの停止時においてもコア８がマグネット５によって磁気的に吸引されているので、支持体７下端面と座台６の上端面の隙間αはモータの回転、停止にかかわらず常に一定に維持される。
【００４１】
また、ハウジング２を例えば厚さ０．１０〜０．１５ｍｍ程度の薄手のステンレス鋼（例えばＳＵＳ３０３）で構成して若干弾性を有するものとし、振動モータに衝撃が与えられるとハウジング２が若干変形して分銅１３の上端面に接触し、分銅に掛かる荷重をハウジングで受け、分銅から支持体に掛かる衝撃を緩和するように構成してある。なお、ハウジングの厚さを０．１０ｍｍ未満にすると、ハウジングによるステータヨークの支持が不安定となるおそれがあり、また０．１５ｍｍよりも大にすると上述した衝撃の緩和作用が十分に得られない。
したがって、スラスト方向の衝撃力に対しても充分な強度が得られる。
【００４２】
次ぎに、上述した実施例の振動モータの製作工程について説明する。
まず、予め保護部材９をモールドしたコア８の各極歯８ｂの脚部にコイル１０を捲装し、隣り合う極歯８ｂ、８ｂとコア本体部８ａとの間に支持体７の支持突起７ｃを嵌入し、フランジ部７ｂの外周辺部をコア８の内周下辺部に当接せしめ、支持突起とコアとの間を接着固定する。
【００４３】
そしてコイル１０の巻線端部を整流子１１に接続し、その後、分銅の溝１３ａをコア８の外周辺部に嵌合せしめて接着固定する。
以上の工程により、支持体７、コア８および分銅１３よりなる回転部材が製作される。
【００４４】
上述した回転部材の製作工程とは別に、ステータヨーク３をハウジング２の中央孔２ｂ内に加締め固定し、ステータヨークの外周面にマグネット５を接着により固定し、その後、ステータヨークの縦孔３ａ内に固定軸４の上端を圧入や接着等により固定する。
【００４５】
そして固定軸４にその下端側からランナー１４を遊嵌し、前述した工程によりコア８、分銅１３を予め取り付けた支持体７の円筒部７ａを固定軸４に嵌合せしめ、その後、固定軸４の下端に座台６の中央凹部６ａを圧嵌や接着により固定する。
【００４６】
次ぎに、ベース１を、その中央孔１ａ内に座台下部６ｃが臨むように取り付け、この状態でハウジング２の下端部を外側から加締め、さらに接着剤にてベース１まわりに固定する。
【００４７】
その後、座台６の小径部６ｃとベースの中央孔１ａ内面との間に接着剤を流し込んで硬化せしめる。かくすることにより、固定軸４の上端部を支持しているステータヨーク３のハウジング２に対する取り付け位置やハウジング２のベース１に対する取り付け位置に水平方向の誤差が生じて、これらの誤差によって固定軸４の上端位置がずれても、固定軸の上端位置のずれに対応して固定軸の下端を支持する座台６の水平方向の位置がベースの中央孔１ａ内で移動するので、製作時における組み付け誤差によって固定軸に傾きが生じるようなおそれはまずない。
【００４８】
したがって、固定軸の傾きによって回転部材がハウジングやベースに接触するというような製作時の組み付け誤差に起因する不良品の発生が殆どなくなり、製品歩留まりの向上を期すことができる。
【００４９】
なお、座台６とベース１間の接着には、任意のタイミングで迅速に硬化させることができる紫外線硬化タイプや２剤混合タイプの接着剤を用いるのが好適である。
【００５０】
上述した第１実施例の振動モータにおいては、分銅１３の内面に形成した溝１３ａをコア８の外周辺部に嵌合固定する構成としてあるが、図３、４に示す第２実施例のもののようにコア８の外周辺部の上下面にそれぞれ上下の分銅１６ａ、１６ｂを接着固定して、分銅全体をコアの上下面と重なるようにする場合もあり、この場合には各分銅の外周面をコア８の外周面に揃え、分銅の内周面がコイル１０に接触しないように分銅とコイルとの間に保護部材９を介在せしめる。
【００５１】
この第２実施例のものでは、分銅１６ａ、１６ｂが２分割タイプであるので、第１実施例のものに比して分銅の取り付けに若干の手間が掛かるが、分銅の最大回転半径をコア８の最大回転半径と同じにすることができ、振動モータのより一層の小型化を実現できるというメリットがある。
【００５２】
上述した第１および第２実施例では、ともに円筒状に形成したステータヨーク３内に支持体７の円筒部７ａ上部を臨ませる構成としてあるが、図５に示す第３実施例のもののように、ステータヨーク１７を、固定軸４を嵌入固定せしめるための縦孔１７ａを有する円柱状のもので構成するとともに、支持体１８を、フランジ部１８ｂの上方に円筒部１８ａが突出しない形状のものとし、円筒部がステータヨーク内に臨まない構成とする場合もある。なお、同図５において符号１８ｃは支持突起を示す。
【００５３】
また、同図５のもののように、固定軸４の下端をベース１の上面に形成した欧部１ｃに直接嵌入固定して座台６を設けない場合もある。
【００５４】
上述した第１乃至第３実施例のものは、いずれも軸が回転しない軸固定タイプのものであるが、図６、７に示される第４実施例のもののように軸回転タイプのものとする場合もある。
【００５５】
しかして、第４実施例のものにおいては、上部は閉じているが下部が開口する円筒状のステータヨーク１９内に、低摩擦係数の合成樹脂材よりなる円板状のスラスター２０と、同じく低摩擦係数の合成樹脂材よりなり、上下が開口する円筒状の軸受スリーブ２１を設けてあり、軸受スリーブ２１内に回転軸２２の上半部が回転可能に挿入され、回転軸２２の上端はスラスター２０に当接させられている。
【００５６】
上記軸受スリーブ２１の内周面には、図８に示されるように例えばヘリンボーン状の動圧溝２４を形成してあり、回転軸との間の摩擦をより小ならしめるように構成してある。
なお、回転軸２２の上端は球面状に形成されていて、スラスターに対する接触面積を小ならしめ、回転時の安定性を向上せしめてある。
【００５７】
上記回転軸２２の下半部には、支持体２３を固定してあり、この支持体は整流子を兼ねる円筒部２３ａと、この円筒部の上端部から外側に向かうフランジ部２３ｂと、フランジ部の外周辺部から上方へ突出する複数の支持突起２３ｃとよりなるものとしてある。
【００５８】
この実施例の振動モータにおける他の構成は、第１実施例のものと同じであり、マグネット５の重心を通る水平面ＭＰをコア８の重心を通る水平面ＣＰよりも上方に位置せしめてコア８、支持体２３および回転軸２２よりなる回転部材をマグネットのコアに対する磁気吸引力により上方へ引き付けている。
【００５９】
したがって、回転軸２２の上端は常にスラスター２０に当接させられ、回転軸の下端とベース上面との間には隙間γがあけられ、この隙間γは分銅１３の下端面とベース１上面との間の隙間βとほぼ同じにしてある。
【００６０】
【発明の効果】
本発明に係る振動モータは、ハウジング内に分銅を設けてあるので、振動モータを小型電話機等の被組付機器内に取り付ける際に、分銅の駆動スペースを全く考慮する必要がなく、被組付機器の設計の自由度が格段に向上し、また軸は軸長が短いので、外部からの衝撃によって折れ曲がるような破損のおそれが殆どない。
【００６１】
また、下部が開口するステータヨーク内に、支持体の円筒部の上部を臨ませてあるので、固定軸に対する支持体の組付け長さが大であり、かつ、分銅の重心を通る水平面が円筒部の上部を通り、したがって外部からの衝撃によって分銅に掛かる力のラジアル方向成分が固定軸のほぼ全長に亘って分散し、支持体のねじれや破損のおそれが殆どなく、耐久性の高い振動モータを実現することができる。
【００６２】
さらに、固定軸の下端は座台を介してベースに固定してあり、座台の下部はベースの中央孔に対して水平方向に移動可能な寸法に設定されているので、振動モータの製作工程の最後に座台とベースを接着固定し、この際に座台の水平位置を調節することによって固定軸の立設角度を正確に設定することができ、製作時における各部材の組み付け誤差が生じても、この組み付け誤差によって固定軸に傾きが生じるようなおそれはまずなく、したがって、固定軸の傾きによって回転部材がハウジングやベースに接触するというような製作時の組み付け誤差に起因する不良品の発生が殆どなくなり、製品歩留まりの向上を期すことができる。
【００６３】
また、マグネットの重心を通る水平面を、コアの重心を通る水平面よりも上方に位置せしめてあるので、コアがマグネットの磁力により上方へ吸引され、したがって支持体がコアとともに上方へ引き上げられているので、通常のモータ駆動時すなわち外部からの衝撃を受けていない状態においては、支持体や回転軸がベースと接触するおそれはまずなく、これら支持体や回転体がベースに接触することによる各部材の損傷や磨耗の発生が殆どなく、耐久性が大で寿命の長い振動モータを実現することができる。
【００６４】
さらに、分銅の少なくとも一部がコアのリング状本体部の上下面に重なるように分銅をコアに取り付けるので、分銅をコアの外周縁に取り付ける場合に比して分銅の回転半径を小ならしめることができ、小型の振動モータを実現することができる。
【図面の簡単な説明】
【図１】本発明に係る振動モータの第１実施例を示す縦断正面図。
【図２】図１のＩＩ−ＩＩ線横断平面図。
【図３】本発明に係る振動モータの第２実施例を示す縦断正面図。
【図４】図３のＩＶ−ＩＶ線横断平面図。
【図５】本発明に係る振動モータの第３実施例を示す縦断正面図。
【図６】本発明に係る振動モータの第４実施例を示す縦断正面図。
【図７】図６のＶＩＩ−ＶＩＩ線横断平面図。
【図８】軸受スリーブの縦断斜視図。
【図９】従来の振動モータの一例を示す斜視図。
【符号の説明】
１ベース
２ハウジング
３ステータヨーク
４固定軸
５マグネット
６座台
７支持体
８コア
９保護部材
１０コイル
１１整流子
１２ブラシ
１３分銅
１４ランナー
１５端子
１６ａ、１６ｂ分銅
１７ステータヨーク
１８支持体
１９ステータヨーク
２０スラスター
２１軸受スリーブ
２２回転軸
２３支持体
２４動圧溝[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a small vibration motor having an eccentric weight and suitable for calling a vibrator of a small telephone such as a mobile phone or a PHS (Personal Handyphone System).
[0002]
[Prior art and its problems]
Conventionally, there are various types of vibration motors having an eccentric weight.
In recent years, in small telephones such as mobile phones and PHS, a small vibration motor is provided in the telephone as a means for notifying ringing without ringing, and instead of ringing, the vibration motor is driven to drive the telephone itself. There is one that vibrates and informs the user of an incoming call by this vibration, and such a telephone function is mounted on almost all small telephones as a “vibration function”.
[0003]
As a vibration motor that has been generally used for the applications described above, there is a vibration motor as shown in FIG. 9, and an eccentric weight 33 is attached to the tip of a rotating shaft 32 led out from the motor body 31 to the outside. ing.
[0004]
Since such a vibration motor is housed inside a mobile phone or the like that has been further downsized in recent years, an extremely small motor body 31 having a diameter of about 6 mm and a length of about 12 mm is used. The shaft 32 has a diameter of about 0.7 mm and the eccentric weight 33 generally has a weight of about 0.5 to 0.7 g.
[0005]
However, since the eccentric weight 33 is provided outside the motor body 31 in the conventional vibration motor described above, these components are arranged so that the eccentric weight does not contact other components such as an electronic circuit inside the telephone. Has a problem in that the degree of freedom of the mounting position is low.
[0006]
Further, in addition to being small as described above, an eccentric motor used in a small telephone is required to have sufficient strength against a drop impact.
[0007]
However, in the above-described conventional one, the eccentric weight 33 is provided at the tip of the thin rotating shaft 32 having a diameter of about 0.7 mm. Therefore, when a radial impact is applied to the rotating shaft 32, it is derived from the motor body 31. The force due to the impact concentrates on the base portion of the portion where it is formed, and it is easy to bend at this portion, and the eccentric weight comes into contact with the surrounding members in the telephone and cannot be rotated.
[0008]
In particular, if the eccentric amount or weight of the eccentric weight is increased for the purpose of increasing the amount of vibration (vibration strength), the force applied to the rotating shaft at the time of dropping increases, and the strength against dropping impact decreases. To do.
[0009]
In addition to the small telephones described above, the vibration motor generates a predetermined vibration in a measuring machine such as an industrial test device, is used as a vibration source for virtual reality experience in a game machine, or a small anomaly. As in the case of the above-described vibration motors for small telephones, improvement in impact resistance and further miniaturization are demanded for these purposes.
[0010]
【the purpose】
An object of the present invention is to provide a vibration motor that can obtain a sufficient amount of vibration and that has a high degree of freedom in mounting space for a device to be assembled such as a small telephone and has sufficient strength against impact. It is in.
[0011]
[Configuration of the present invention]
In order to achieve the above object, a vibration motor according to claim 1 of the present invention has a cylindrical housing that has a top plate but is open at the bottom and is fixed on the base, and is magnetized in the radial direction on the top plate of the housing. The upper end of a stator yoke having a ring-shaped magnet on the outer periphery is fixed, the lower end of a fixed shaft with the upper end inserted and fixed in a vertical hole formed in the center of the stator yoke is fixed to the base, and the lower part is a commutator The inner surface is opposed to the outer peripheral surface of the magnet. The support body includes a cylindrical portion that also serves as a flange, a flange portion that extends outward from the cylindrical portion, and a plurality of support protrusions that protrude upward from the outer peripheral portion of the flange portion. A plurality of pole teeth on the inner side of the ring-shaped main body, a coil is provided around the legs of each pole tooth, and an eccentric weight is attached to the outer periphery between adjacent pole teeth of the core. Support Attach the core by fitting the supporting protrusion, is as commutator in the lower part of the support is rotatable about the fixed shaft support in contact with the brush provided on the base.
[0012]
In the vibration motor according to claim 2 of the present invention, the stator yoke is formed in a cylindrical shape having an opening at the lower portion, and the upper portion of the cylindrical portion of the support body faces the stator yoke.
[0013]
In the vibration motor according to a third aspect of the present invention, the lower end of the fixed shaft is fitted and fixed in a central recess formed on the upper surface of a cylindrical seat having an outer peripheral flange at the upper portion, and the lower portion of the seat has a base The seat is fixed to the base so as to face the center hole having an inner diameter larger than the outer diameter of the lower portion of the seat.
[0014]
According to a fourth aspect of the present invention, there is provided a vibration motor in which a large inner diameter portion having a slightly larger inner diameter than that of the upper and lower portions is formed on the inner surface of the cylindrical portion of the support so that the oil is interposed between the fixed shaft and the cylindrical portion. A reservoir is provided.
[0015]
In the vibration motor according to claim 5 of the present invention, the horizontal plane passing through the center of gravity of the magnet is positioned above the horizontal plane passing through the center of gravity of the core, and the core is always attracted upward by the magnetic force of the magnet. As a thing.
[0016]
In the vibration motor according to claim 6 of the present invention, a cylindrical housing having a top plate but having an opening at the bottom is fixed on the base, and the top plate of the housing is closed at the top but opened at the bottom and is attached in the radial direction. The upper end of a stator yoke having a magnetized ring-shaped magnet on the outer periphery is fixed, a cylindrical bearing sleeve is fitted and fixed in the stator yoke, and the lower part also serves as a commutator, and the outer side from the cylindrical part A plurality of pole teeth whose inner surface faces the outer peripheral surface of the magnet, and a support body comprising a flange portion facing toward the outer periphery and a plurality of support protrusions projecting upward from the outer peripheral portion of the flange portion. On the inner side of the ring-shaped main body, a coil is mounted around the leg of each pole tooth, and an eccentric weight is attached to the outer peripheral part. The core is attached to the support by being inserted, and the upper part of the rotating shaft is rotatably mounted in the bearing sleeve so that the commutator in the lower part of the support contacts the brush provided on the base. .
[0017]
In the vibration motor according to claim 7 of the present invention, a dynamic pressure groove is formed on the inner surface of the bearing sleeve.
[0018]
In the vibration motor according to claim 8 of the present invention, the eccentric weight is attached to the core so that at least a part thereof overlaps the upper and lower surfaces of the ring-shaped main body portion of the core.
[0019]
A first embodiment of the vibration motor according to the present invention is configured such that the housing is made of a material having a slight elasticity, a thickness, and is elastically deformed when subjected to an impact from the outside and contacts the upper end surface of the weight. The shock applied to the weight is dispersed in the housing so that the shock is mitigated.
[0020]
In the second embodiment, the housing is made of stainless steel having a thickness of 0.10 to 0.15 mm.
[0021]
Further, in the third embodiment, the gap α between the lower end of the cylindrical portion of the support and the upper surface of the base and the gap β between the lower surface of the weight and the upper surface of the weight are set to substantially the same size, and the weight is in the thrust direction. When the impact is applied, the lower end surface of the weight and the lower end surface of the support come into contact with the upper surface of the base almost simultaneously to disperse the impact.
[0022]
【Example】
Hereinafter, embodiments of the vibration motor according to the present invention will be described in detail based on specific examples shown in the accompanying drawings.
In the figure, reference numeral 1 denotes a base, 2 denotes a housing, and the upper end portion of the stator yoke 3 is caulked and fixed in a hole 2b formed in the center of a top plate 2a of the housing 2 formed in a cylindrical shape with a lower opening. .
[0023]
The stator yoke 3 is formed in a cylindrical shape with an opening at the bottom, and the upper end of the fixed shaft 4 is fixed by press-fitting or bonding in a vertical hole 3a opened in the center of the top, and a ring shape is formed on the outer periphery of the stator yoke. The magnet 5 is attached, and this magnet is magnetized in the radial direction.
[0024]
A seat 6 is provided at the lower end of the fixed shaft 4, and the lower end of the fixed shaft is fitted and fixed to a central recess 6a formed on the upper surface of the seat, and the lower surface of the outer peripheral flange 6b is the center hole 1a of the base. Is supported by the upper surface of the stepped portion 1b formed on the upper inner peripheral surface of the first stepped portion, and is fixed to the stepped portion by an adhesive.
[0025]
The seat 6 is provided with an appropriate play between the outer peripheral surface of the seat lower portion 6c and the inner peripheral surface of the central hole 1a of the base so that it can move in the horizontal direction before bonding to the stepped portion. After the centering is performed, the seat is fixed to the stepped portion by means such as adhesion, so that the fixed shaft can be accurately suspended from the base.
[0026]
Thus, a support 7 is provided on the outer periphery of the fixed shaft 4 between the stator yoke 3 and the seat 6 so as to be rotatable around the fixed shaft, and the upper part of the cylindrical portion 7a of the support is disposed in the stator yoke 3. The support body has a flange portion 7b on the outer periphery of the central portion in the axial direction of the cylindrical portion 7a, and a plurality of support protrusions 7c and 7c projecting upward are formed on the outer peripheral portion of the flange portion. The cylindrical portion, the flange portion, and the support protrusion are integrally formed of the same material using a synthetic resin material such as polyphenylene sulfide.
[0027]
A large inner diameter portion 7d having a slightly larger inner diameter than the upper and lower portions of the inner surface of the cylindrical portion is formed at the central portion in the axial direction of the inner surface of the cylindrical portion 7a. It functions as an oil sump and smoothes the rotation of the support 7 with respect to the fixed shaft 4.
[0028]
The support 7 supports the inner peripheral portion of the core 8. The core protrudes inward from the inner side of the ring-shaped core main body 8 a, and the pole teeth 8 b whose inner side faces the outer peripheral surface of the magnet 5. , 8b.
[0029]
Further, the support protrusions 7c and 7c of the support body 7 are fitted between the adjacent pole teeth 8b and 8b of the core 8 and the inner peripheral surface of the core body portion 8a, and the core is aligned with the support body by the support protrusions. And the core is supported together with the flange portion.
[0030]
The core 8 is made of, for example, a silicon steel plate, and is provided with a protective member 9 made of a synthetic resin material such as polybutylene terephthalate by molding at least around the upper and lower surfaces and the legs of the pole teeth, and the legs of each pole tooth 8b. A coil 10 is fitted around the part so that the coil winding does not directly contact the core.
[0031]
The winding end of the coil 10 is connected to a commutator 11 provided below the cylindrical portion 7 a of the support 7, and this commutator is provided so as to come into contact with the brush 12 provided on the base 1. Yes.
[0032]
Further, a tile-like weight 13 which is an eccentric weight is attached to the outer peripheral portion of the core 8, and this weight is made of, for example, tungsten, and a groove 13a formed in the longitudinal direction of the inner peripheral surface is formed in the outer peripheral portion of the core. And is fixed with an adhesive or the like. When the weight is provided with a groove and fitted into the core in this way, the weight overlaps the top and bottom surfaces of the core by the depth of the groove, and therefore the weight rotates compared to the case where a weight without a groove is attached to the outer periphery of the core. The radius can be reduced, and the vibration motor can be reduced in size.
[0033]
The core 8 is positioned below the magnet 5 in the axial direction, and more specifically, the horizontal plane MP passing through the center of gravity of the magnet 5 is positioned above the horizontal plane CP passing through the center of gravity of the core. The core is always attracted upward by the magnetic force of the magnet.
[0034]
Therefore, the upper end of the cylindrical portion 7a is brought into contact with the runner 14, and the support rotates with a gap between the lower end of the cylindrical portion and the pedestal. In a normal use state, the lower end of the cylindrical portion is on the upper surface of the pedestal. There is an advantage that a long-life vibration motor can be realized without contact and without risk of damage or wear due to contact between the lower end of the cylindrical portion and the upper surface of the seat.
[0035]
In addition, the code | symbol 14 in a figure is a ring-like runner which consists of a synthetic resin material of the bottom friction coefficient interposed between the upper end surface of the cylindrical part 7a, and the top inner surface of the stator yoke 3, 15 is connected with the brush 12, The terminal led out of the housing 2 is shown.
[0036]
In the vibration motor of the present invention configured as described above, when a driving current is supplied to the terminal 15, the coil 10 is energized through the brush 12 and the commutator 11, and the magnetic force generated in the pole teeth of the core 8 and the magnet 5 The core is rotationally driven around the fixed shaft 4 together with the support 7 and the weight 13 by the magnetic attraction / repulsion force between them, and vibration is generated with the eccentric rotation of the weight 13.
[0037]
When the vibration motor receives an impact due to dropping or the like, the fixed shaft 4 has a short shaft length, and both ends are supported by the stator yoke 3 and the seat 6, and a support body 7 is provided between the both end support portions. Therefore, there is hardly a possibility that the impact force concentrates on a part of the rotating shaft and damages the rotating shaft.
[0038]
Further, the support 7 has an upper portion of the cylindrical portion 7a facing the inside from the lower opening of the stator yoke 3, and the contact length in the axial direction between the support and the rotating shaft is increased. Since the force applied to the shaft is sufficiently dispersed and the horizontal plane passing through the center of gravity of the weight passes through the upper portion of the cylindrical portion 7a of the support body, the radial component of the force applied to the weight due to the drop impact is applied to the upper portion of the cylindrical portion. It is difficult for the body to twist, and therefore the strength against the impact force in the radial direction is large.
[0039]
Furthermore, in the vibration motor of the present embodiment, the clearance α between the lower end surface of the cylindrical portion of the support 7 and the upper end surface of the base 6 and the clearance β between the lower end surface of the weight 13 and the upper end surface of the base 1 are as follows. When the weight 13 and the support 7 are moved downward due to the thrust direction component of the drop impact force, the lower end surface of the weight and the lower end surface of the support contact the upper surface of the base 1 almost simultaneously. The impact is distributed.
[0040]
Since the core 8 is magnetically attracted by the magnet 5 even when the motor is stopped, the gap α between the lower end surface of the support 7 and the upper end surface of the seat 6 is always constant regardless of whether the motor is rotating or stopped. Maintained.
[0041]
Further, the housing 2 is made of thin stainless steel (for example, SUS303) having a thickness of about 0.10 to 0.15 mm, for example, and has a slight elasticity. When an impact is applied to the vibration motor, the housing 2 is slightly deformed. The weight 13 is in contact with the upper end surface of the weight 13 and receives the load applied to the weight by the housing, so that the impact applied from the weight to the support is reduced. If the thickness of the housing is less than 0.10 mm, the support of the stator yoke by the housing may become unstable, and if it is greater than 0.15 mm, the above-described impact mitigating action cannot be sufficiently obtained. .
Therefore, sufficient strength can be obtained even with respect to the impact force in the thrust direction.
[0042]
Next, the manufacturing process of the vibration motor of the above-described embodiment will be described.
First, the coil 10 is mounted on the leg portion of each pole tooth 8b of the core 8 in which the protective member 9 is preliminarily molded, and the support protrusion 7c of the support body 7 between the adjacent pole teeth 8b and 8b and the core body portion 8a. The outer peripheral portion of the flange portion 7b is brought into contact with the inner peripheral lower side portion of the core 8, and the support protrusion and the core are bonded and fixed.
[0043]
Then, the winding end portion of the coil 10 is connected to the commutator 11, and then a weight groove 13 a is fitted to the outer peripheral portion of the core 8 to be bonded and fixed.
The rotating member which consists of the support body 7, the core 8, and the weight 13 is manufactured by the above process.
[0044]
Separately from the manufacturing process of the rotating member described above, the stator yoke 3 is caulked and fixed in the central hole 2b of the housing 2, the magnet 5 is fixed to the outer peripheral surface of the stator yoke by adhesion, and then the vertical hole 3a of the stator yoke is fixed. The upper end of the fixed shaft 4 is fixed inside by press-fitting or bonding.
[0045]
Then, the runner 14 is loosely fitted to the fixed shaft 4 from the lower end side, and the cylindrical portion 7a of the support 7 to which the core 8 and the weight 13 are previously attached is fitted to the fixed shaft 4 by the above-described process. The central recess 6a of the seat 6 is fixed to the lower end of the base 6 by press fitting or adhesion.
[0046]
Next, the base 1 is attached so that the seat lower portion 6c faces the center hole 1a. In this state, the lower end of the housing 2 is crimped from the outside, and further fixed around the base 1 with an adhesive.
[0047]
Thereafter, an adhesive is poured between the small diameter portion 6c of the seat 6 and the inner surface of the central hole 1a of the base to be cured. Thus, horizontal errors occur in the mounting position of the stator yoke 3 supporting the upper end of the fixed shaft 4 with respect to the housing 2 and the mounting position of the housing 2 with respect to the base 1, and these errors cause the fixed shaft 4. Even if the upper end position of the base shaft is shifted, the horizontal position of the seat 6 that supports the lower end of the fixed shaft moves within the central hole 1a of the base in response to the shift of the upper end position of the fixed shaft. There is almost no risk that the fixed shaft will be tilted due to an error.
[0048]
Therefore, there is almost no generation of defective products due to assembly errors during manufacture such that the rotating member comes into contact with the housing or the base due to the inclination of the fixed shaft, and the product yield can be improved.
[0049]
For the adhesion between the base 6 and the base 1, it is preferable to use an ultraviolet curing type adhesive or a two-component mixed type adhesive that can be quickly cured at an arbitrary timing.
[0050]
In the above-described vibration motor of the first embodiment, the groove 13a formed on the inner surface of the weight 13 is configured to be fitted and fixed to the outer peripheral portion of the core 8, but the second embodiment shown in FIGS. In this case, the upper and lower weights 16a and 16b are bonded and fixed to the upper and lower surfaces of the outer peripheral portion of the core 8, respectively, so that the entire weight overlaps with the upper and lower surfaces of the core. Are aligned with the outer peripheral surface of the core 8, and a protective member 9 is interposed between the weight and the coil so that the inner peripheral surface of the weight does not contact the coil 10.
[0051]
In the second embodiment, since the weights 16a and 16b are of a two-part type, it takes a little time to install the weight as compared to the first embodiment, but the maximum turning radius of the weight is set to the core 8. There is an advantage that the vibration motor can be further miniaturized.
[0052]
In the first and second embodiments described above, the upper portion of the cylindrical portion 7a of the support body 7 faces the inside of the stator yoke 3 formed in a cylindrical shape. However, as in the third embodiment shown in FIG. The stator yoke 17 is formed of a columnar shape having a vertical hole 17a for fitting and fixing the fixed shaft 4, and the support body 18 has a shape in which the cylindrical portion 18a does not protrude above the flange portion 18b. In some cases, the cylindrical portion does not face the stator yoke. In FIG. 5, reference numeral 18c denotes a support protrusion.
[0053]
In addition, as in FIG. 5, there is a case where the seat 6 is not provided by directly fitting and fixing the lower end of the fixed shaft 4 to the European portion 1 c formed on the upper surface of the base 1.
[0054]
All of the first to third embodiments described above are of a fixed shaft type in which the shaft does not rotate, but are of a shaft rotation type such as those of the fourth embodiment shown in FIGS. In some cases.
[0055]
Thus, in the fourth embodiment, the cylindrical stator yoke 19 which is closed at the top but opened at the bottom has a disk-like thruster 20 made of a synthetic resin material having a low coefficient of friction, and also has a low A cylindrical bearing sleeve 21 made of a synthetic resin material having a friction coefficient and having upper and lower openings is provided. The upper half of the rotary shaft 22 is rotatably inserted into the bearing sleeve 21, and the upper end of the rotary shaft 22 is a thruster. 20.
[0056]
As shown in FIG. 8, for example, a herringbone-shaped dynamic pressure groove 24 is formed on the inner peripheral surface of the bearing sleeve 21, and the friction with the rotating shaft is further reduced. .
Note that the upper end of the rotating shaft 22 is formed in a spherical shape, so that the contact area with the thruster is reduced and the stability during rotation is improved.
[0057]
A support body 23 is fixed to the lower half portion of the rotating shaft 22, and the support body is a cylindrical portion 23 a that also serves as a commutator, a flange portion 23 b that extends outward from the upper end portion of the cylindrical portion, and a flange portion. The plurality of support protrusions 23c projecting upward from the outer peripheral portion of the head.
[0058]
Other configurations of the vibration motor of this embodiment are the same as those of the first embodiment, and the core 8 is configured such that the horizontal plane MP passing through the center of gravity of the magnet 5 is positioned above the horizontal plane CP passing through the center of gravity of the core 8. A rotating member composed of the support 23 and the rotating shaft 22 is attracted upward by a magnetic attractive force with respect to the core of the magnet.
[0059]
Therefore, the upper end of the rotating shaft 22 is always brought into contact with the thruster 20, and a gap γ is formed between the lower end of the rotating shaft and the upper surface of the base, and this gap γ is between the lower end surface of the weight 13 and the upper surface of the base 1. The gap β is approximately the same.
[0060]
【The invention's effect】
Since the vibration motor according to the present invention has a weight in the housing, there is no need to consider the drive space of the weight when mounting the vibration motor in a device to be assembled such as a small telephone. The degree of freedom in designing the device is greatly improved, and the shaft has a short shaft length, so there is almost no risk of breakage due to external impact.
[0061]
In addition, since the upper part of the cylindrical part of the support body faces the stator yoke with the lower part opened, the assembly length of the support body with respect to the fixed shaft is large, and the horizontal plane passing through the center of gravity of the weight is cylindrical. Highly durable vibration motor that passes through the top of the part, and therefore the radial component of the force applied to the weight due to external impact is distributed over almost the entire length of the fixed shaft, and there is almost no risk of twisting or breakage of the support. Can be realized.
[0062]
Furthermore, the lower end of the fixed shaft is fixed to the base via the seat, and the lower part of the seat is set to a dimension that can move in the horizontal direction with respect to the center hole of the base. At the end of this step, the base and base are bonded and fixed, and by adjusting the horizontal position of the base at this time, the standing angle of the fixed shaft can be set accurately, resulting in assembly errors for each member during production. However, it is unlikely that the fixed shaft will be tilted due to this assembly error, and therefore, defective products due to assembly errors during production such as the rotating member coming into contact with the housing or the base due to the tilt of the fixed shaft. Is almost eliminated and the product yield can be improved.
[0063]
In addition, since the horizontal plane passing through the center of gravity of the magnet is positioned above the horizontal plane passing through the center of gravity of the core, the core is attracted upward by the magnetic force of the magnet, so the support is pulled up together with the core. During normal motor driving, i.e., when no impact is applied from the outside, there is little possibility that the support and the rotating shaft will come into contact with the base. A vibration motor with almost no damage and wear, high durability, and long life can be realized.
[0064]
Furthermore, since the weight is attached to the core so that at least a part of the weight overlaps the upper and lower surfaces of the ring-shaped body of the core, the turning radius of the weight should be smaller than when attaching the weight to the outer periphery of the core. Therefore, a small vibration motor can be realized.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view showing a first embodiment of a vibration motor according to the present invention.
FIG. 2 is a cross-sectional plan view taken along line II-II in FIG.
FIG. 3 is a longitudinal front view showing a second embodiment of the vibration motor according to the present invention.
4 is a cross-sectional plan view taken along line IV-IV in FIG. 3;
FIG. 5 is a longitudinal front view showing a third embodiment of the vibration motor according to the present invention.
FIG. 6 is a longitudinal front view showing a fourth embodiment of the vibration motor according to the present invention.
7 is a cross-sectional plan view taken along line VII-VII in FIG. 6;
FIG. 8 is a vertical perspective view of a bearing sleeve.
FIG. 9 is a perspective view showing an example of a conventional vibration motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Base 2 Housing 3 Stator yoke 4 Fixed shaft 5 Magnet 6 Seat 7 Support body 8 Core 9 Protection member 10 Coil 11 Commutator 12 Brush 13 Weight 14 Runner 15 Terminal 16a, 16b Weight 17 Stator yoke 18 Support body 19 Stator yoke 20 Thruster 21 Bearing sleeve 22 Rotating shaft 23 Support 24 Dynamic pressure groove

Claims

A cylindrical housing having a top plate but having an opening at the bottom is fixed on the base, and an upper end portion of a stator yoke having a ring-shaped magnet magnetized in a radial direction is fixed to the top plate of the housing. The lower end of the fixed shaft whose upper end is fitted and fixed in the vertical hole in the center of the base is fixed to the base, the lower part is a cylindrical part that also serves as a commutator, the flange part that faces outward from the cylindrical part, and the flange part A plurality of pole teeth whose inner side faces the outer peripheral surface of the magnet are provided inside the ring-shaped main body, and each pole tooth A coil is fitted around the leg portion of the core, and an eccentric weight is attached to the outer periphery of the core. Vibration motor child is provided rotatably about the fixed shaft support in contact with the brush provided on the base.

2. The vibration motor according to claim 1, wherein the stator yoke is formed in a cylindrical shape having an opening at a lower portion, and an upper portion of the cylindrical portion of the support body faces the stator yoke.

The lower end of the fixed shaft is fitted and fixed in a central recess formed on the upper surface of a cylindrical seat having an outer peripheral flange at the top, and the lower portion of the seat is opened in the base, and the outer diameter of the lower portion of the seat is The vibration motor according to claim 1, wherein the seat is fixed to the base so as to face the central hole having a larger inner diameter.

The vibration according to claim 1, wherein a large inner diameter portion having a slightly larger inner diameter than the upper and lower portions is formed on an inner surface of the cylindrical portion of the support body, and an oil reservoir is provided between the fixed shaft and the cylindrical portion. motor.

The vibration motor according to claim 1, wherein a horizontal plane passing through the center of gravity of the magnet is positioned above a horizontal plane passing through the center of gravity of the core, and the core is always attracted upward by the magnetic force of the magnet.

A cylindrical housing having a top plate but having an opening at the bottom is fixed on the base, and a stator having a ring-shaped magnet that is closed at the top but opened at the bottom and magnetized in the radial direction on the top plate of the housing. The upper end of the yoke is fixed, and a cylindrical bearing sleeve is fitted and fixed in the stator yoke. A support body composed of a plurality of support protrusions projecting upward from the portion is fixed around the rotation axis, and a plurality of pole teeth whose inner side faces the outer peripheral surface of the magnet are provided inside the ring-shaped main body, A coil is fitted around the leg of each pole tooth, and the support protrusion of the support is inserted between the adjacent pole teeth of the core having an eccentric weight attached to the outer periphery, and the core is attached to the support. Vibration motor commutator in the lower support member is rotatably mounted on the upper portion of the rotary shaft so as to contact with the brush provided on the base in the bearing sleeve.

The vibration motor according to claim 6, wherein a dynamic pressure groove is formed on an inner surface of the bearing sleeve.

The vibration motor according to claim 1 or 6, wherein the eccentric weight is attached to the core so that at least a part thereof overlaps the upper and lower surfaces of the ring-shaped main body portion of the core.