JP2004208475A

JP2004208475A - Insulation structure of, and insulation method for stator core

Info

Publication number: JP2004208475A
Application number: JP2002377749A
Authority: JP
Inventors: Takeshi Yamaguchi; 毅山口; Shingo Hashimoto; 伸吾橋本; Toru Azeyanagi; 徹畔柳
Original assignee: Aisin AW Co Ltd
Current assignee: Aisin AW Co Ltd
Priority date: 2002-12-26
Filing date: 2002-12-26
Publication date: 2004-07-22

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulation structure to which a mold construction method can be applied even in the case that a stator core is long lengthwise and besides which is excellent in electric insulation, and to provide an insulation method. <P>SOLUTION: This is an insulation structure for getting the electric insulation of the stator core 2 which has an annular yoke 20, a plurality of teeth 22 projected inward in the radial direction and slots 25 made between the teeth 22. Insulating members 3 consisting of sheet materials having electric insulation are wound on the teeth 22 to cover all the periphery mostly. A resin mold film 4 consisting of synthetic resin is formed at least at a section not covered with the insulating member 3 and at the bottom 251 of the slots 25 out of the surface 205 of the yoke end and the surface 225 of the tooth end of the stator core 2. In the vicinity of the proximal end of the tooth 22, an overlap 5 is made all around where a mold film 4 and the insulating member 3 overlap each other. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【技術分野】
本発明は，ステータコアに装着するコイルとステータコアとの間の電気絶縁性を得るための絶縁構造及び絶縁方法に関する。
【０００２】
【従来技術】
電動モータ等の回転電動機に用いられるステータコアには，そのスロットにワイヤを巻回して形成したコイルが挿入配置される。コイルを構成する各ワイヤには，電気絶縁性を確保するため電気絶縁性樹脂等により被覆を行っているが，より十分な電気絶縁性を得るために，ステータコアにおけるコイルが接触する部分に絶縁処理が施されるのが普通である。
【０００３】
従来のステータコアの絶縁処理としては，例えば，電気絶縁性を有するシート状の絶縁紙をステータコアのスロット内に配置する方法や，ステータコアのほぼ全面を電気絶縁性を有する合成樹脂によってコーティングするモールド工法等がある。モールド工法は，ステータコアにおける各々のティース部にそれぞれ１つのコイルを装着する集中巻き構造の場合に多用されている。
上記絶縁紙を用いた絶縁方法としては，例えば次の特許文献１に開示されているものがある。
【０００４】
【特許文献１】
特開平７−７５２７３号公報
【０００５】
【解決しようとする課題】
ところで，上記モールド工法では，ステータコアの両端面を全面的に覆い，かつ，ティース部の全周を覆うように樹脂モールド皮膜が形成されるので，絶縁特性において有利ではある。
しかしながら，ステータコアの軸長が長い，すなわち，ステータコアを構成する鋼板の積層厚みが厚い場合には，ティース部の側面であるスロット部に面するスロット内壁面全体に合成樹脂を流動させるようなモールド処理を行うことが困難である。なお，形成する樹脂モールド皮膜を十分に厚くすれば，合成樹脂の流動性が向上し，上記スロット内壁面全体に樹脂モールド皮膜を形成することが可能となるが，この場合には，電磁気的特性が低下して好ましくない。したがって，ステータコアの軸長が長い場合などには，モールド工法を適用することができない。
【０００６】
また，絶縁紙による絶縁方法においては，絶縁紙を成形して挿入するが，ステータコアの軸方向の両端面全体を覆い，かつスロット部に面するスロット内壁面全体をも覆うことは困難である。そのため，いわゆる沿面電流の発生を防止するための沿面距離を十分に確保できない場合も生じうる。
【０００７】
本発明は，かかる従来の問題点に鑑みてなされたもので，ステータコアの軸長が長い場合にもモールド工法が適用でき，かつ，電気絶縁性に優れた絶縁構造及び絶縁方法を提供しようとするものである。
【０００８】
【課題の解決手段】
第１の発明は，リング状のヨーク部と，該ヨーク部を基端として径方向内方に突設した複数のティース部及び該ティース部の間に形成されたスロット部とを有するステータコアの電気絶縁性を得るための絶縁構造において，
上記ティース部には，少なくともその一部分のほぼ全周を覆うように，電気絶縁性を有する絶縁部材が配設されており，
また，上記ステータコアの軸方向の両端面に面する上記ヨーク部のヨーク端表面のうち少なくとも一部と，上記ステータコアの軸方向の両端面に面する上記ティース部のティース端表面のうち少なくとも上記絶縁部材により覆われていない部分と，上記スロット部に面するスロット内壁面のうち上記絶縁部材よりも径方向外方に位置するスロット底面部とには，合成樹脂よりなる樹脂モールド皮膜が形成されており，
かつ，上記樹脂モールド皮膜と上記絶縁部材とが重なり合ったオーバーラップ部が，少なくとも，上記ティース部の基端部近傍において該ティース部の全周にわたって形成されていることを特徴とするステータコアの絶縁構造にある（請求項１）。
【０００９】
本発明のステータコアの絶縁構造においては，ステータコアにおける絶縁すべき部分を，上記絶縁部材又は樹脂モールド皮膜により覆っている。そのため，スロット部に挿入配置されたコイルとティース部及びヨーク部との直接接触を防止することができる。
【００１０】
更に，本発明では，上記ティース部の基端部近傍において，上記絶縁部材とティース部とが重なり合って存在する上記オーバーラップ部を形成している。そのため，絶縁部材と樹脂モールド皮膜との境界部分における沿面距離を積極的に増大させることができ，沿面電流の発生を防止することができる。さらには，上記オーバーラップ部の存在によって，絶縁部材が樹脂モールド皮膜と十分に係合し，絶縁部材の位置ずれを防止することもできる。
【００１１】
また，さらなる効果として，上記ティース部の周囲は上記絶縁部材によって絶縁することができるので，スロット部に面するティース部の側面（上記スロット内壁面の一部）には，樹脂モールド皮膜を形成する必要がない。そして，スロット部に面する上記スロット内壁面のうち，比較的厚みを大きくすることが許される上記スロット底面部のみに上記樹脂モールド皮膜を形成すればよい。そのため，後述する実施例にも示すように，絶縁部材を装着した後にモールド工法を適用して上記樹脂モールド皮膜を形成する手法を採用することができる。それ故，ステータコアの軸長が長い場合でも，上記の絶縁構造をモールド工法を利用して実現することができる。
【００１２】
第２の発明は，リング状のヨーク部と，該ヨーク部を基端として径方向内方に突設した複数のティース部及び該ティース部の間に形成されたスロット部とを有するステータコアの電気絶縁性を得るための絶縁方法において，
上記ティース部の少なくともその一部分のほぼ全周を覆うように，電気絶縁性を有する絶縁部材を配設する絶縁部材配設工程と，
上記ステータコアを型内にセットし，該型内に合成樹脂を流し込んで，上記ステータコアの表面の少なくとも一部に樹脂モールド皮膜を形成するモールド工程とを行い，
かつ，上記モールド工程においては，上記ステータコアの軸方向の両端面に面する上記ヨーク部のヨーク端表面のうち少なくとも一部と，上記ステータコアの軸方向の両端面に面する上記ティース部のティース端表面のうち少なくとも上記絶縁部材により覆われていない部分と，上記スロット部に面するスロット内壁面のうち上記絶縁部材よりも径方向外方に位置するスロット底面部とに，上記樹脂モールド皮膜を形成すると共に，
少なくとも，上記ティース部の基端部近傍において，上記ティース部と上記絶縁部材の間又は／及び該絶縁部材の表面上に上記合成樹脂を流入させて上記樹脂モールド皮膜を形成することにより，
該樹脂モールド皮膜と上記絶縁部材とが重なり合ったオーバーラップ部を，少なくとも，上記ティース部の基端部近傍において該ティース部の全周にわたって形成することを特徴とするステータコアの絶縁方法にある（請求項１０）。
【００１３】
本発明の絶縁方法では，上記のごとく，絶縁部材配設工程を行った後に，上記モールド工程を実施する。これにより，上述した第１の発明の絶縁構造を確実に実現することができる。
そして，さらに注目すべきことは，上記モールド工程において，単に絶縁部材に覆われていない部分のみに樹脂モールド皮膜を形成するのだけでなく，少なくともティース部の基端部近傍においてティース部と絶縁部材との間隙又は絶縁部材の上のいずれかあるいは両方に合成樹脂を積極的に流入させ，上記オーバーラップ部を形成することである。これにより，絶縁部材と樹脂モールド皮膜との係合関係が十分に得られ，絶縁部材の位置ずれを防止することができる。さらには，上述したごとく，絶縁部材と樹脂モールド皮膜との境界部分における沿面電流の発生を防止することができる。
【００１４】
【発明の実施の形態】
上記第１及び第２の発明における上記ステータコアは，珪素鋼板等を積層することにより作製される。
また，上記絶縁部材としては，電気的絶縁性を有する様々なシート材を用いることができる。例えば，従来の絶縁紙として用いられていたアラミド樹脂のシート，カプトンフィルム，ポリエチレンフィルム等がある。また，上記樹脂モールド皮膜として適用する合成樹脂としては，電気絶縁性，ある程度の耐熱性を兼ね備えたものであれば，様々な合成樹脂，プラスチックなどを用いることができる。この中でも，例えば，ＬＣＰ（Liquid Crystal Polymer）と呼ばれる液晶ポリマーは，強度特性にも優れ特に好ましい。
【００１５】
また，上記第１の発明において，上記ティース端表面においては，その全面にわたって，該ティース端表面上又は／及び上記絶縁部材上に上記樹脂モールド皮膜が形成されており，該ティース端表面に対面する上記絶縁部材全面が上記オーバーラップ部を形成していることが好ましい（請求項２）。
この場合には，上記ティース端表面全体が樹脂モールド皮膜によって覆われた上に，さらに上記オーバーラップ部においては絶縁部材が存在する状態，又は，ティース端表面上に直接絶縁部材が存在しその全体の上にさらに樹脂モールド皮膜が存在する状態，あるいは，ティース端表面と樹脂モールド皮膜との間と樹脂モールド皮膜上の両方に樹脂モールド皮膜が存在する状態が得られる。これにより，さらに絶縁効果，及び沿面電流発生防止効果を高めることができると共に，オーバーラップ部の増大によって絶縁部材の固定効果を高めることができる。
【００１６】
また，上記オーバーラップ部のうち少なくとも一部は，上記ティース部上に上記樹脂モールド皮膜が存在し，該樹脂モールド皮膜の表面上に上記絶縁部材が存在している二重積層構造を有している構造をとることができる（請求項３）。
【００１７】
また，上記オーバーラップ部のうち少なくとも一部は，上記ティース部上に上記絶縁部材が存在し，該絶縁部材上に上記樹脂モールド皮膜が存在している二重積層構造を有している構造をとることもできる（請求項４）。
【００１８】
さらには，上記オーバーラップ部のうち少なくとも一部は，上記ティース部上に上記樹脂モールド皮膜が存在し，該樹脂モールド皮膜の表面上に上記絶縁部材が存在し，さらに該絶縁部材上に上記樹脂モールド皮膜が存在している三重積層構造を有している構造をとることもできる。
いずれの構造においても，上記オーバーラップ部としての機能を十分に発揮することができる。
【００１９】
また，上記ティース端表面と上記絶縁部材との間には，合成樹脂よりなる樹脂パーツを介設した構造をとることが好ましい（請求項５）。この場合には，上記樹脂パーツに，上記絶縁部材との係合機能を設けることによって，絶縁部材の配設を容易に行うことができる。例えば後述するようにクリップで絶縁部材を係止できる構造などを採用することができる。
なお，上記樹脂パーツの材料としては，例えば，ＬＣＰ等の電気絶縁性を有する合成樹脂材料を適用することができる。
【００２０】
また，上記絶縁部材は，上記ティース端表面の少なくとも一方の面上において重なり合った重合部を有していることが好ましい（請求項６）。
この場合には，シート状の上記絶縁部材によって容易にリング形状を形成することができる。また，上記重合部をティース端表面上に配設することによって，コイルの配設状態に支障を来すことがほとんどない状態で，上記重合部を形成することができる。なお，上記重合部においては，後述するごとく，絶縁部材を構成するシート同士を接合してもよいし，樹脂モールド皮膜との噛み込み効果のみを利用して固定してもよい。
【００２１】
また，上記絶縁部材は，上記重合部において接合してあることが好ましい（請求項７）。
この場合には，絶縁部材の配設状態をより安定化させることができる。なお，この場合の接合方法としては，例えば，熱圧着，超音波接合，接着剤での接合などの方法がある。
【００２２】
また，上記絶縁部材は，上記オーバーラップ部において切り欠き部又は突起部を有しており，該切り欠き部又は突起部と上記樹脂モールド皮膜とが噛み込み状態を形成することによって上記絶縁部材が固定されている構造をとることもできる（請求項８）。この場合には，上記重合部による接合がなくても絶縁部材をティース部に配設することが可能となる。なお，この切り欠き部又は突起部と上記樹脂モールド皮膜とが噛み込み状態の形成と，上記の重合部の接合を併用することも可能であり，最も好ましい。
【００２３】
また，上記オーバーラップ部は，上記ステータコアの径方向において，少なくとも４ｍｍ以上形成されていることが好ましい（請求項９）。オーバーラップ部が４ｍｍ未満の場合には，沿面電流の防止効果が十分に得られないおそれがある。なお，オーバーラップ部は可能な限り上記径方向に長い方が好ましい。また，上記のオーバーラップ部の寸法の最適な範囲は，コイルに供給される電圧容量によって変更することが好ましい。
【００２４】
次に，上記第２の発明において，上記モールド工程においては，上記ティース端表面とこれに対面する上記絶縁部材との間隙又は／及び該絶縁部材の表面上に全体に上記合成樹脂を流入させて上記樹脂モールド皮膜を形成することが好ましい（請求項１１）。
この場合には，ティース端表面に対面する上記絶縁部材全面が上記オーバーラップ部を形成している構造を実現することができる。これにより，上述したごとく，さらに絶縁効果，及び沿面電流発生防止効果を高めることができると共に，オーバーラップ部の増大によって絶縁部材の固定効果を高めた絶縁構造を得ることができる。
【００２５】
また，上記絶縁部材配設工程においては，上記ティース端表面上に合成樹脂よりなる樹脂パーツを介設し，その後上記絶縁部材を配設することもできる（請求項１２）。この場合には，上記樹脂パーツと上記絶縁部材との係合により絶縁部材を固定することができるので，その配設作業を容易化することができる。
【００２６】
【実施例】
実施例１
本発明の実施例に係るステータコアの絶縁構造及びステータコアの絶縁方法につき，図１〜図８を用いて説明する。
本例のステータコアの絶縁構造１は，図１〜図３に示すごとく，リング状のヨーク部２０と，該ヨーク部２０を基端として径方向内方に突設した複数のティース部２２及び該ティース部２２の間に形成されたスロット部２５とを有するステータコア２の電気絶縁性を得るための絶縁構造である。
【００２７】
図３に示すごとく，ティース部２２には，少なくともその一部分のほぼ全周を覆うように，電気絶縁性を有する絶縁部材３が配設されている。また，ステータコア２の軸方向の両端面に面するヨーク部２０のヨーク端表面２０５（図１）のうち少なくとも一部と，ステータコア２の軸方向の両端面に面するティース部２２のティース端表面２２５のうち少なくとも絶縁部材３により覆われていない部分と，スロット部２５に面するスロット内壁面２５０のうち絶縁部材３よりも径方向外方に位置するスロット底面部２５１とには，合成樹脂よりなる樹脂モールド皮膜４が形成されている。
かつ，樹脂モールド皮膜４と絶縁部材３とが重なり合ったオーバーラップ部５が，少なくとも，ティース部２２の基端部近傍においてティース部２２の全周にわたって形成されている。
さらに，本例では，ティース端表面２２５においては，その全面にわたって上記樹脂モールド皮膜４が形成されており，ティース端表面２２５に対面する絶縁部材３全面が上記オーバーラップ部５を形成している。
以下，これを詳説する。
【００２８】
上記ステータコア２は，図１に示すごとく，リング状に打ち抜いた多数の珪素鋼板を積層して構成してある。ステータコア２は，上記のごとく，リング状のヨーク部２０を有し，ヨーク部２０を基端として径方向内周側に突設した複数のティース部２２及びティース部２２の間に形成されたスロット部２５とを有している。本例のティース部２２は，内周端側において周方向に突出した突出部２２９を有しており，対面する突出部２２９の間には，スロット部２５の入り口となるスロットオープン部２５８（図４）が形成されている。
【００２９】
このような構造のステータコア２において上記絶縁構造１を得るため，本例では，まず，図２に示すごとく，ティース部２２の少なくともその一部分のほぼ全周を覆うように，電気絶縁性を有するシート材よりなる絶縁部材３を配設する絶縁部材配設工程を行う。
【００３０】
より具体的には，ステータコア３用の素材として，従来よりモータ用の絶縁紙として多用されている，アラミド繊維のシートを用いた。そして，図２に示すごとく，ティース部２２の突起部２２９近傍及び基端部近傍を除く大部分を覆うように全周に巻き付けて，一方のティース端表面２２５上において重ね合わせて重合部３２を設けた。さらに重合部３２は，超音波接合して一体化した。
【００３１】
次に，本例では，絶縁部材３をすべてのティース部２２に配設した後，ステータコア２を，樹脂モールド用の型内にセットし（図示略），型内に合成樹脂を流し込んで，ステータコア２の表面の少なくとも一部に樹脂モールド皮膜４を形成するモールド工程を行った。
【００３２】
本例は，上記型内にステータコア２をセットした際に，絶縁部材３の周囲を型で覆うと共に，樹脂モールド皮膜４を形成しようとする部分に合成樹脂が入り込むキャビティとなる空間を設けた。
この空間は，まず，ステータコア２の軸方向両端面に面するヨーク部２０のヨーク端表面２０５のうち少なくとも一部と，同じくステータコア２の軸方向の両端面に面するティース部２２のティース端表面２２５のうち絶縁部材３により覆われていない部分全部と，スロット部２５に面するスロット内壁面２５０のうち絶縁部材３よりも径方向外方に位置するスロット底面部２５１とに設けた。
【００３３】
さらに，ティース部２２と絶縁部材３との間にも上記空間を設けた。ここで，両ティース端表面２２５と絶縁部材３との間には，径方向にほぼ一定の間隙が形成されるようにした。具体的には，ティース端表面２２５からおよそ１〜２ｍｍ程度の間隙を設けた。また，ティース部２２のスロット部２５に面する側面（スロット内壁面２５０の一部）と絶縁部材３との間は，ティース部２２の先端側である突起部２２９近傍においてはほとんど隙間を無くし，ティース部２２の基端側，つまり上記スロット内壁面２５０のうち上記スロット底面部２５１に近いスロット奥側面部２５２においては比較的大きな間隙が空くようにした。具体的には，スロット奥側面部２５２においては，ティース部２２と絶縁部材３との隙間がおよそ０．２〜０．３ｍｍとなるようにした。
【００３４】
また，上記合成樹脂としては，ＬＣＰ（Liquid Crystal Polymer）を用いた。そして，この合成樹脂を上記型内に充填した。これにより，図３〜図８に示すごとく，合成樹脂は，まず，ステータコア２の軸方向の両端面に面する上記ヨーク部２０のヨーク端表面２０５及び上記ティース部２２のティース端表面２２５のうち少なくとも絶縁部材３により覆われていない部分と，上記スロット底面部２５１とを覆い，樹脂モールド皮膜４となる。
【００３５】
また，スロット内壁面２５０のティース部２２の基端部近傍であるスロット奥側面部２５２においては，ティース部２２と絶縁部材３の間の全周に合成樹脂が流入し，樹脂モールド皮膜４が形成され，樹脂モールド皮膜４と絶縁部材３とが重なり合ったオーバーラップ部５が形成された。
さらに，ティース部２２のティース端表面２２５と絶縁部材３の間においては，基端部側だけでなく，先端部側まで全面的に合成樹脂が流入し，樹脂モールド皮膜４が形成された。これにより，ティース端表面２２５においては，その全面にわたって樹脂モールド皮膜４が形成され，ティース端表面２２５に対面する絶縁部材３の全面が上記オーバーラップ部５を形成した。
【００３６】
上記の絶縁方法により得られた絶縁構造１を，各部の断面などから説明したのが図４〜図８である。これらの図は，便宜上，曲率を持った部分も直線的に示した説明図である。
図４は，上面からみた説明図である。図５は，図３におけるＡ−Ａ線矢視断面図である。図６は，図４におけるＢ−Ｂ線矢視断面図である。図７は，図４におけるＣ−Ｃ線矢視断面図である。図８は，図４におけるＤ−Ｄ線矢視断面図である。
【００３７】
図３，図４に表された外観から知られるように，ステータコア２の軸方向端面は，樹脂モールド皮膜４あるいは絶縁部材３によって全面的に覆われていることがわかる。
また，図５〜図７より知られるように，ティース部２２の側面は，その基端部側，すなわちスロット奥側面部２５２の部分において樹脂モールド皮膜４と絶縁部材３とが重なったオーバーラップ部５を形成しているが，先端側では絶縁部材３のみに覆われていることがわかる。そして，本例のティース部２２の側面におけるオーバーラップ部５は，図５に示すごとく，その径方向の幅Ｗが約４ｍｍとなっている。
【００３８】
また，図５〜図８に示すごとく，本例におけるオーバーラップ部５は，いずれの部分においても，ティース部２２上に樹脂モールド皮膜４が存在し，樹脂モールド皮膜４の表面上に絶縁部材３が存在している二重積層構造を有している。
【００３９】
次に，本例の作用効果につき説明する。
本例のステータコアの絶縁構造においては，ステータコア２における絶縁すべき部分を，上記絶縁部材３又は樹脂モールド皮膜４により覆っている。そのため，スロット部２５に挿入配置されたコイル８とティース部２２及びヨーク部２０との直接接触を防止することができる。
【００４０】
更に，本例では，ティース部２２の基端部近傍において，絶縁部材３とティース部２２との間に樹脂モールド皮膜４が介在していて，上記オーバーラップ部５を形成している。そのため，絶縁部材３と樹脂モールド皮膜４との境界部分における沿面距離を積極的に増大させることができ，沿面電流の発生を防止することができる。さらには，上記オーバーラップ部５の存在によって，絶縁部材３が樹脂モールド皮膜４と十分に係合し，絶縁部材３の位置ずれを防止することもできる。
【００４１】
また，ティース部２２の周囲は絶縁部材３によって絶縁することができるので，スロット部２５に面するティース部２２の側面（スロット内壁面２５０の一部）には，樹脂モールド皮膜４を形成する必要がない。スロット内壁面２５０のうち，比較的厚みを大きくすることが許されるスロット底面部２５１近傍のみに樹脂モールド皮膜４を形成すればよい。そのため，上記のごとく，絶縁部材３を装着した後にモールド工法を適用して樹脂モールド皮膜４を形成する手法を積極的に採用することができる。それ故，ステータコア３の軸長が長い場合でも，上記の絶縁構造１をモールド工法を利用して実現することができる。
【００４２】
さらに，本例では，ティース端表面２２５においては，その全面にわたって樹脂モールド皮膜４が形成されており，ティース端表面２２５に対面する絶縁部材３の全面がオーバーラップ部５を形成している。そのため，さらに絶縁効果，及び沿面電流発生防止効果を高めることができると共に，オーバーラップ部５の増大によって絶縁部材の固定効果を高めることができる。
【００４３】
実施例２
本例は，図９に示すごとく，実施例１における絶縁部材３の両端に，切り欠き部としての貫通穴３６を設けた例である。
本例では，この貫通穴３６を一方のティース端表面２５２上において重ね合わせて重合部を形成し，上記のモールド工法を実施した。
これにより，上記のモールド工程において充填される樹脂モールド皮膜４が貫通穴３６に流入して重合部における絶縁部材３の接合効果を発揮する。それ故，さらなる工程の合理化を図ることができる。
その他は実施例１と同様の作用効果が得られる。
【００４４】
実施例３
本例は，図１０〜図１２に示すごとく，実施例１における絶縁構造に代えて，オーバーラップ部５の絶縁部材３と樹脂モールド皮膜４の配置を逆転させた例である。
すなわち，同図に示すごとく，本例では，オーバーラップ部５のすべてにおいて，ティース部２２上に絶縁部材３が存在し，その絶縁部材３上に樹脂モールド皮膜４が存在している二重積層構造を採用した。また，オーバーラップ部５は，実施例１と同様に，ティース部２２の側面側では，その基端部近傍であるスロット奥側面部２５２のみに形成し，ティース端表面２２５上においては絶縁部材３が存在する全面に形成した。その他は実施例１と同様である。
【００４５】
この場合には，その製造時の絶縁部材配設工程において，絶縁部材３をティース部２２の周りに殆ど隙間なく配設し，そして，モールド工程で使用する金型によって所望の部分のみにキャビティを形成すれば製造できる。そのため，絶縁部材３とティース部２２との隙間の寸法を管理する必要がほとんどなく製造が容易になる。その他，実施例１と同様の作用効果が得られる。
【００４６】
実施例４
本例は，図１３，図１４に示すごとく，実施例３における基本構造を踏襲し，更に，一方のティース端表面２２５上における絶縁部材３の接合を，別部材であるキャップ部材３３により行った例である。
【００４７】
まず，本例の絶縁部材３は，同図に示すごとく，一方のティース端表面２２５上に面する形状を変更した。すなわち，上記ティース部２２の側面に当接する側面部３１０からティース端表面２２５側に折れ曲がった第１折れ片部３１１と，これに連なってティース端表面２２５から離れる方向に折れ曲がった第２折れ片部３１２と，更に，第２折れ片部３１２の先端から第１折れ片部３１１の方へ折り返された第３折れ片部３１３とを有する形状とした。
【００４８】
またキャップ部材３３は，断面略カップ形状を呈し，その開口部においてその開口径を縮径するように内方へ曲げて形成した係合部３３１を有する部材である。このキャップ部材３３は，絶縁部材３と同材質により作製したものである。
【００４９】
そして，本例では，絶縁部材配設工程において，絶縁部材３をティース部２２に巻き付けた後，その第３折り返し片部３３１にキャップ部材３３を被せ，その係合部３３１を係合させることにより，絶縁部材３を固定する。そして，その後モールド工程を実施する。
【００５０】
これにより，図１３，図１４に示すごとく，ティース部２２の一方のティース端表面２２５上においては，樹脂モールド皮膜４と絶縁部材３及びキャップ３３が積層し，さらにその上面に樹脂モールド皮膜４が積層した三層構造が得られる。
【００５１】
本例の場合には，上記キャップ３３を用いることにより，絶縁部材配設工程において絶縁部材３を固定する作業を容易化することができる。その他は，実施例１と同様の作用効果が得られる。
【００５２】
実施例５
本例は，図１５，図１６に示すごとく，実施例３における基本構造を踏襲し，更に，一方のティース端表面２２５と絶縁部材３との間には，合成樹脂よりなる樹脂パーツ６１を介設した例である。
本例の樹脂パーツ６１は，同図に示すごとく，ティース端表面２２５に当接する底面部６１０と，その中央部において立設され底面部６１０から離れるほど幅寸法が大きくなるような逆テーパ形状を呈した立設部６１１とを有している。また，立設部６１１の上面部６１２には，後述するピン３５を挿入する挿入穴６１３が形成されている。
【００５３】
また，本例の絶縁部材３は，同図に示すごとく，上記ティース部２２の側面に当接する側面部３２０から上記樹脂パーツ６１の底面部６１０の表面に沿ってティース端表面２２５側に折れ曲がった第１折れ片部３２１と，これに連なってティース端表面２２５から離れる方向に折れ曲がった第２折れ片部３２２と，更に，第２折れ片部３２２の先端から上記樹脂パーツ６１に接する方向に折り返された第３折れ片部３２３とを有する形状とした。
【００５４】
更に，本例では，同図に示すごとく，断面略カップ状のキャップ部材３４とピン３５とを用いた。
キャップ部材３４は，上記第２折れ片部３２３を覆うような断面略カップ形状を有し，その底面部３４０の中央に貫通穴３４１を有している。また，ピン３５はそのピン本体部３５０よりも大径の頭部３５１を有していると共に，上記ピン本体部３５０の径は，上記樹脂パーツ６１の挿入穴６１３に圧入されて係合しうるように設計されている。
【００５５】
そして，本例の絶縁構造を得るための絶縁部材配設工程では，絶縁部材３を配設する前に，ティース端表面２２５上に合成樹脂よりなる樹脂パーツ６１を介設し，その後絶縁部材３を配設する。そして，上記キャップ部材３４を絶縁部材３の第２折り返し片部３２２を覆うように被せた後，ピン３５をキャップ部材３４の貫通穴３４１を貫通させて樹脂パーツ６１の挿入穴６１３に圧入することにより，絶縁部材３の固定を行うことができる。
また，この固定構造においては，絶縁部材３の第３折り返し片３２３が樹脂パーツ６１の立設部６１１の逆テーパ形状とうまく係合し，固定状態をより安定化させることができる。
【００５６】
そして，その後，実施例１，２と同様にしてモールド工程を行うことにより，本例の絶縁構造を得ることができる。
本例の場合には，上記のごとく，絶縁部材配設工程において絶縁部材３の固定を容易に行うことができ，製造工程をさらに合理化することができる。
その他は実施例１と同様の作用効果が得られる。
【００５７】
実施例６
本例では，図１７，図１８に示すごとく，実施例５の場合とは形状を変更した樹脂パーツ６２を採用し，また，絶縁部材３の形状及びキャップ部材３３の形状を実施例４の場合と同様にした例である。
本例の樹脂パーツ６２は，同図に示すごとく，ティース端表面２２５に当接する底面部６２０と，その中央部において立設され底面部６２０から離れるほど幅寸法が小さくなるようなテーパ形状を呈した立設部６２１とを有している。
【００５８】
この場合には，絶縁部材配設工程では，絶縁部材３を配設する前に，ティース端表面２２５上に合成樹脂よりなる樹脂パーツ６２を介設し，その後絶縁部材３を配設する。そして，上記キャップ部材３３を絶縁部材３の第３折り返し片部３１３を覆うように被せ，これに係合部３３１を係合させる。これにより，絶縁部材３の固定を行うことができる。このとき，本例では，樹脂パーツ６２の存在によって，この固定構造を実施例４の場合よりもより安定化させることができる。その他，上述した他の実施例と同様の作用効果が得られる。
【００５９】
実施例７
本例は，図１９に示すごとく，実施例６における樹脂パーツ６２を，ティース部２２の両方のティース端表面２２５に配設した例である。
この場合には，絶縁部材３の形状を，キャップ部材３３を配設する側と反対側のティース端表面２２５に対面する部分において略台形状に変更した。より具体的には，樹脂パーツ６２の先端面６２２に当接する平坦部３１７と，側面部３１０との間を結ぶ傾斜部３１６とを有する形状とした。その他は実施例６と同様である。
【００６０】
この場合には，ステータコア２の軸方向両端面におけるティース端表面にそれぞれ同形状の樹脂パーツ６２を配設する。そのため，この時点までは，少なくとも表裏対象の状態でステータコアを取り扱うことができ，工程管理を容易にすることができる。さらに樹脂パーツ６２と絶縁部材３との間に樹脂モールド皮膜４の合成樹脂が入り込むため，合成樹脂と絶縁部材との結合力を高くすることができ，ステータコア２から樹脂モールド皮膜４又は絶縁部材３が剥離してしまうことを防止することができる。その他は実施例６と同様である。
【００６１】
実施例８
本例は，図２０，図２１に示すごとく，実施例６の場合と形状を変更したキャップ部材３６を採用した例である。
すなわち，同図に示すごとく，キャップ部材３６は，断面略カップ状を呈し，その係合部３６１は，その先端に内方に突出した爪部３６２を有し，第３折り返し片部３１３の先端面３１４に係合するように構成されている。
【００６２】
なお，絶縁部材３の形状は実施例６の場合と同様であり，また，樹脂パーツ６３の形状も実施例６の場合と基本的に同じで立設部６３１の幅寸法を若干大きくした点だけが異なる。
【００６３】
本例の場合には，キャップ部材３６が上記のごとく爪部３６２を有しているので，これを絶縁部材３の第３折り返し片部３１３の先端面３１４に係合させることにより，絶縁部材３の固定構造をより強固にすることができる。
その他，上述したその他の実施例の場合と同様の作用効果が得られる。
【００６４】
実施例９
本例は，図２１に示すごとく，実施例８における樹脂パーツ６３を，ティース部２２の両方のティース端表面２２５に配設した例である。
この場合にも，絶縁部材３の形状を，キャップ部材３６を配設する側と反対側のティース端表面２２５に対面する部分において，樹脂パーツ６３の先端面６３２に当接する平坦部３１７と，側面部３１０との間を結ぶ傾斜部３１６とを有する形状とした。その他は実施例８と同様である。
【００６５】
この場合にも，ステータコア２の軸方向両端面におけるティース端表面にそれぞれ同形状の樹脂パーツ６３を配設するので，この時点までは，少なくとも表裏対象の状態でステータコアを取り扱うことができ，工程管理を容易にすることができる。さらに樹脂パーツ６３と絶縁部材３との間に樹脂モールド皮膜４の合成樹脂が入り込むため，合成樹脂と絶縁部材との結合力を高くすることができ，ステータコア２から樹脂モールド皮膜４又は絶縁部材３が剥離してしまうことを防止することができる。その他，上述した実施例と同様の作用効果が得られる。
【図面の簡単な説明】
【図１】実施例１における，ステータコアの構造を示す説明図。
【図２】実施例１における，絶縁部材配設工程完了状態を示す説明図。
【図３】実施例１における，ステータコアの絶縁構造を示す説明図。
【図４】実施例１における，ステータコアの絶縁構造を上面（端面側）からみた説明図。
【図５】実施例１における，ステータコアの積層面に沿った断面からみた横断面図（図３のＡ−Ａ線矢視断面図）。
【図６】実施例１における，ティース部のスロットオープン部近傍においてステータコアの周方向断面からみた縦断面図（図４のＢ−Ｂ線矢視断面図）。
【図７】実施例１における，ティース部の基端部近傍においてステータコアの周方向断面からみた縦断面図（図４のＣ−Ｃ線矢視断面図）。
【図８】実施例１における，ティース部をステータコアの軸方向に平行な径方向断面からみた縦断面図（図４のＤ−Ｄ線矢視断面図。
【図９】実施例２における，絶縁部材の切り欠き部としての貫通穴を示す説明図。
【図１０】実施例３における，ステータコアの積層面に沿った断面からみた横断面図（図３のＡ−Ａ線矢視断面図に相当）。
【図１１】実施例３における，ティース部のスロットオープン部近傍においてステータコアの周方向断面からみた縦断面図（図４のＢ−Ｂ線矢視断面図に相当）。
【図１２】実施例３における，ティース部の基端部近傍においてステータコアの周方向断面からみた縦断面図（図４のＣ−Ｃ線矢視断面図に相当）。
【図１３】実施例４における，ティース部のスロットオープン部近傍においてステータコアの周方向断面からみた縦断面図（図４のＢ−Ｂ線矢視断面図に相当）。
【図１４】実施例４における，ティース部の基端部近傍においてステータコアの周方向断面からみた縦断面図（図４のＣ−Ｃ線矢視断面図に相当）。
【図１５】実施例５における，ティース部のスロットオープン部近傍においてステータコアの周方向断面からみた縦断面図（図４のＢ−Ｂ線矢視断面図に相当）。
【図１６】実施例５における，ティース部の基端部近傍においてステータコアの周方向断面からみた縦断面図（図４のＣ−Ｃ線矢視断面図に相当）。
【図１７】実施例６における，ティース部のスロットオープン部近傍においてステータコアの周方向断面からみた縦断面図（図４のＢ−Ｂ線矢視断面図に相当）。
【図１８】実施例６における，ティース部の基端部近傍においてステータコアの周方向断面からみた縦断面図（図４のＣ−Ｃ線矢視断面図に相当）。
【図１９】実施例７における，ティース部のスロットオープン部近傍においてステータコアの周方向断面からみた縦断面図（図４のＢ−Ｂ線矢視断面図に相当）。
【図２０】実施例８における，ティース部のスロットオープン部近傍においてステータコアの周方向断面からみた縦断面図（図４のＢ−Ｂ線矢視断面図に相当）。
【図２１】実施例８における，ティース部の基端部近傍においてステータコアの周方向断面からみた縦断面図（図４のＣ−Ｃ線矢視断面図に相当）。
【図２２】実施例９における，ティース部のスロットオープン部近傍においてステータコアの周方向断面からみた縦断面図（図４のＢ−Ｂ線矢視断面図に相当）。
【符号の説明】
１．．．ステータコアの絶縁構造，
２．．．ステータコア，
２０．．．ヨーク部，
２２．．．ティース部，
２５．．．スロット部，
３．．．絶縁部材，
４．．．樹脂モールド皮膜，
５．．．オーバーラップ部，[0001]
【Technical field】
The present invention relates to an insulation structure and an insulation method for obtaining electrical insulation between a coil mounted on a stator core and a stator core.
[0002]
[Prior art]
A coil formed by winding a wire around a slot is inserted and arranged in a stator core used for a rotary electric motor such as an electric motor. Each wire that composes the coil is coated with an electrically insulating resin or the like to ensure electrical insulation. To obtain more sufficient electrical insulation, insulation is applied to the part of the stator core where the coil contacts. Is usually applied.
[0003]
Conventional insulation treatment of the stator core includes, for example, a method of arranging a sheet of insulating paper having electrical insulation in a slot of the stator core, and a molding method of coating almost the entire surface of the stator core with a synthetic resin having electrical insulation. There is. The molding method is frequently used in the case of a concentrated winding structure in which one coil is attached to each tooth portion of the stator core.
As an insulating method using the insulating paper, for example, there is a method disclosed in Patent Document 1 below.
[0004]
[Patent Document 1]
JP-A-7-75273
[0005]
[Problem to be solved]
By the way, in the above-mentioned molding method, the resin mold film is formed so as to cover both end surfaces of the stator core entirely and to cover the entire periphery of the teeth portion, which is advantageous in terms of insulation characteristics.
However, if the axial length of the stator core is long, that is, if the thickness of the steel sheets constituting the stator core is large, a molding process is performed such that the synthetic resin flows over the entire inner wall surface of the slot facing the slot, which is the side surface of the teeth. Is difficult to do. If the resin mold film to be formed is sufficiently thick, the fluidity of the synthetic resin is improved, and it is possible to form the resin mold film on the entire inner wall surface of the slot. Is undesirably reduced. Therefore, when the axial length of the stator core is long, the molding method cannot be applied.
[0006]
In the insulating method using insulating paper, the insulating paper is formed and inserted. However, it is difficult to cover the entire axial end surfaces of the stator core and also cover the entire inner wall surface facing the slot portion. Therefore, there may be a case where a creeping distance for preventing generation of a so-called creeping current cannot be sufficiently secured.
[0007]
The present invention has been made in view of such conventional problems, and an object of the present invention is to provide an insulating structure and an insulating method that can be applied to a molding method even when the axial length of a stator core is long, and have excellent electrical insulation properties. Things.
[0008]
[Means for solving the problem]
According to a first aspect of the present invention, there is provided an electric stator core having a ring-shaped yoke, a plurality of teeth protruding radially inward from the yoke as a base end, and a slot formed between the teeth. In the insulation structure to obtain insulation,
The teeth portion is provided with an insulating member having electrical insulation so as to cover at least a part of the teeth.
Further, at least a part of the yoke end surface of the yoke portion facing the axial both end surfaces of the stator core and at least the insulating portion of the tooth end surface of the tooth portion facing the axial end surfaces of the stator core. A resin mold film made of a synthetic resin is formed on the portion not covered by the member and on the slot bottom surface located radially outward of the insulating member on the slot inner wall surface facing the slot portion. Yes,
An insulation structure for a stator core, wherein an overlap portion in which the resin mold film and the insulation member overlap with each other is formed at least in the vicinity of the base end of the teeth portion over the entire periphery of the teeth portion. (Claim 1).
[0009]
In the stator core insulating structure of the present invention, a portion of the stator core to be insulated is covered with the insulating member or the resin mold film. Therefore, it is possible to prevent direct contact between the coil inserted into the slot portion and the teeth portion and the yoke portion.
[0010]
Further, in the present invention, the overlap portion in which the insulating member and the tooth portion overlap each other is formed near the base end of the tooth portion. Therefore, the creepage distance at the boundary between the insulating member and the resin mold film can be positively increased, and the generation of creepage current can be prevented. Further, the presence of the overlap portion allows the insulating member to sufficiently engage with the resin mold film, thereby preventing displacement of the insulating member.
[0011]
As a further effect, since the periphery of the teeth portion can be insulated by the insulating member, a resin mold film is formed on the side surface of the teeth portion facing the slot portion (part of the inner wall surface of the slot). No need. Then, the resin mold film may be formed only on the bottom surface of the slot, which is allowed to have a relatively large thickness, among the inner wall surfaces of the slot facing the slot. Therefore, as shown in an embodiment described later, a method of forming the resin mold film by applying a molding method after mounting the insulating member can be adopted. Therefore, even when the axial length of the stator core is long, the above-described insulating structure can be realized by using the molding method.
[0012]
According to a second aspect of the present invention, there is provided a stator core having a ring-shaped yoke, a plurality of teeth protruding radially inward from the yoke as a base end, and a slot formed between the teeth. In the insulation method to obtain insulation,
An insulating member arranging step of arranging an insulating member having electrical insulation so as to cover substantially the entire periphery of at least a part of the teeth portion;
Performing a molding step of setting the stator core in a mold, pouring a synthetic resin into the mold, and forming a resin mold film on at least a part of the surface of the stator core;
In the molding step, at least a part of the yoke end surface of the yoke portion facing the axial both end surfaces of the stator core and the tooth end of the tooth portion facing the axial end surfaces of the stator core. The resin mold film is formed on at least a portion of the surface that is not covered by the insulating member and a slot bottom surface portion of the slot inner wall surface facing the slot portion that is located radially outward from the insulating member. Along with
At least in the vicinity of the base end of the teeth, between the teeth and the insulating member and / or by flowing the synthetic resin onto the surface of the insulating member to form the resin mold film,
A method of insulating a stator core, comprising forming an overlap portion where the resin mold film and the insulating member overlap each other at least in the vicinity of the base end of the tooth portion over the entire circumference of the tooth portion. Item 10).
[0013]
In the insulating method of the present invention, as described above, after the insulating member arranging step is performed, the above-described molding step is performed. Thereby, the above-described insulating structure of the first invention can be reliably realized.
It should be further noted that, in the above-mentioned molding process, not only the resin mold film is formed only on the portion not covered with the insulating member, but also at least in the vicinity of the base end of the tooth portion. The synthetic resin is positively flown into one or both of the gap and the insulating member to form the overlap portion. Thereby, a sufficient engagement relationship between the insulating member and the resin mold film can be obtained, and the displacement of the insulating member can be prevented. Further, as described above, it is possible to prevent the generation of the creeping current at the boundary between the insulating member and the resin mold film.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The stator core in the first and second inventions is manufactured by laminating a silicon steel plate or the like.
Further, as the insulating member, various sheet materials having electrical insulation properties can be used. For example, there are an aramid resin sheet, a Kapton film, a polyethylene film and the like which have been used as conventional insulating paper. As the synthetic resin applied as the resin mold film, various synthetic resins, plastics, and the like can be used as long as they have electrical insulation and a certain degree of heat resistance. Among them, for example, a liquid crystal polymer called LCP (Liquid Crystal Polymer) is particularly preferable because of its excellent strength characteristics.
[0015]
Further, in the first invention, the resin mold film is formed on the entire surface of the tooth end surface and / or on the insulating member, and faces the tooth end surface. It is preferable that the entire surface of the insulating member forms the overlap portion.
In this case, the entire surface of the tooth end is covered with the resin mold film, and further, the insulating member is present in the overlapping portion, or the insulating member is present directly on the tooth end surface and the entire surface is covered. A state is obtained in which a resin mold film is further present on the substrate, or a state in which the resin mold film is present both between the teeth end surface and the resin mold film and on the resin mold film. Thereby, the insulating effect and the creeping current generation preventing effect can be further enhanced, and the effect of fixing the insulating member can be enhanced by increasing the overlap portion.
[0016]
Further, at least a part of the overlap portion has a double lamination structure in which the resin mold film exists on the teeth portion and the insulating member exists on the surface of the resin mold film. (Claim 3).
[0017]
Further, at least a part of the overlap portion has a double laminated structure in which the insulating member is present on the teeth portion and the resin mold film is present on the insulating member. It can also be taken (claim 4).
[0018]
Further, at least a part of the overlap portion includes the resin mold film on the teeth portion, the insulating member on the surface of the resin mold film, and the resin member on the insulating member. A structure having a three-layer structure in which a mold film is present may be employed.
In any of the structures, the function as the overlapping portion can be sufficiently exhibited.
[0019]
In addition, it is preferable that a resin part made of a synthetic resin is interposed between the tooth end surface and the insulating member. In this case, by providing the resin part with a function of engaging with the insulating member, the insulating member can be easily arranged. For example, a structure in which the insulating member can be locked by a clip as described later can be adopted.
As a material for the resin parts, for example, a synthetic resin material having electrical insulation such as LCP can be used.
[0020]
Further, it is preferable that the insulating member has an overlapping portion that overlaps on at least one surface of the tooth end surface.
In this case, the ring shape can be easily formed by the sheet-shaped insulating member. Further, by disposing the overlapping portion on the tooth end surface, the overlapping portion can be formed in a state where the arrangement of the coil is hardly hindered. In the overlapping portion, as will be described later, the sheets constituting the insulating member may be joined to each other, or may be fixed using only the effect of biting the resin mold film.
[0021]
Further, it is preferable that the insulating member is joined at the overlapping portion.
In this case, the arrangement state of the insulating member can be further stabilized. The bonding method in this case includes, for example, methods such as thermocompression bonding, ultrasonic bonding, and bonding with an adhesive.
[0022]
The insulating member has a notch or a protrusion in the overlap portion, and the notch or the protrusion and the resin mold film form a biting state, whereby the insulating member is formed. A fixed structure may be adopted (claim 8). In this case, it is possible to dispose the insulating member in the teeth portion without joining by the overlapping portion. In addition, it is possible to combine the formation of the cut-out portion or the protrusion with the resin mold film and the joining of the overlapping portion, and it is most preferable.
[0023]
Preferably, the overlap portion is formed at least 4 mm or more in a radial direction of the stator core. When the overlap portion is less than 4 mm, the effect of preventing the creeping current may not be sufficiently obtained. It is preferable that the overlap portion be as long as possible in the radial direction. Further, it is preferable that the optimal range of the size of the overlap portion is changed according to the voltage capacity supplied to the coil.
[0024]
Next, in the second aspect of the present invention, in the molding step, the synthetic resin is caused to flow into a gap between the tooth end surface and the insulating member facing the tooth end surface and / or the entire surface of the insulating member. It is preferable to form the resin mold film (claim 11).
In this case, it is possible to realize a structure in which the entire surface of the insulating member facing the tooth end surface forms the overlap portion. As a result, as described above, it is possible to further increase the insulating effect and the creeping current generation preventing effect, and it is possible to obtain an insulating structure in which the effect of fixing the insulating member is enhanced by increasing the overlap portion.
[0025]
In the insulating member disposing step, a resin part made of a synthetic resin may be interposed on the tooth end surface, and then the insulating member may be disposed. In this case, since the insulating member can be fixed by the engagement between the resin part and the insulating member, the disposing work can be simplified.
[0026]
【Example】
Example 1
An insulating structure of a stator core and a method of insulating a stator core according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 to 3, the stator core insulating structure 1 of this embodiment includes a ring-shaped yoke portion 20, a plurality of teeth portions 22 projecting radially inward from the yoke portion 20 as a base end, and This is an insulating structure for obtaining electrical insulation of the stator core 2 having the slot portions 25 formed between the teeth portions 22.
[0027]
As shown in FIG. 3, the teeth portion 22 is provided with an insulating member 3 having electrical insulation properties so as to cover at least a part of the teeth 22 substantially entirely. Also, at least a part of the yoke end surface 205 (FIG. 1) of the yoke portion 20 facing the axial both end surfaces of the stator core 2 and the tooth end surface of the tooth portion 22 facing the axial end surfaces of the stator core 2. At least a portion of the slot 225 that is not covered by the insulating member 3 and a slot bottom surface 251 that is located radially outward of the insulating member 3 of the slot inner wall surface 250 that faces the slot 25 are made of synthetic resin. The resin mold film 4 is formed.
Further, an overlap portion 5 in which the resin mold film 4 and the insulating member 3 overlap each other is formed at least in the vicinity of the base end of the tooth portion 22 over the entire periphery of the tooth portion 22.
Further, in the present example, the resin mold film 4 is formed on the entire surface of the tooth end surface 225, and the entire surface of the insulating member 3 facing the tooth end surface 225 forms the overlap portion 5.
The details are described below.
[0028]
As shown in FIG. 1, the stator core 2 is formed by laminating a number of silicon steel sheets punched in a ring shape. As described above, the stator core 2 has a ring-shaped yoke portion 20, and a plurality of teeth portions 22 projecting radially inward from the yoke portion 20 and slots formed between the teeth portions 22. And a part 25. The teeth portion 22 of this example has a protrusion 229 projecting in the circumferential direction on the inner peripheral end side, and a slot open portion 258 (see FIG. 4) is formed.
[0029]
In order to obtain the insulation structure 1 in the stator core 2 having such a structure, in the present embodiment, first, as shown in FIG. An insulating member arranging step of arranging the insulating member 3 made of a material is performed.
[0030]
More specifically, as a material for the stator core 3, a sheet of aramid fiber, which has conventionally been frequently used as insulating paper for motors, was used. Then, as shown in FIG. 2, it is wound around the entire circumference so as to cover most of the teeth portion 22 except for the vicinity of the protrusion 229 and the vicinity of the base end, and is superposed on one of the teeth end surfaces 225 to overlap the overlapped portion 32. Provided. Further, the overlapping portion 32 was integrated by ultrasonic bonding.
[0031]
Next, in this example, after the insulating members 3 are disposed on all the teeth portions 22, the stator core 2 is set in a mold for resin molding (not shown), and synthetic resin is poured into the mold. A molding step of forming the resin mold film 4 on at least a part of the surface of the second mold was performed.
[0032]
In this embodiment, when the stator core 2 is set in the mold, the periphery of the insulating member 3 is covered with the mold, and a space is formed in a portion where the resin mold film 4 is to be formed, as a cavity in which the synthetic resin enters.
First, at least a part of the yoke end surface 205 of the yoke portion 20 facing the axial both end surfaces of the stator core 2 and the tooth end surface of the tooth portion 22 also facing the axial end surfaces of the stator core 2. 225 is provided on the entire portion of the slot inner wall surface 250 facing the slot portion 25 that is not covered with the insulating member 3 and on the slot bottom surface portion 251 located radially outward of the insulating member 3 on the slot inner wall surface 250.
[0033]
Further, the space is provided between the teeth portion 22 and the insulating member 3. Here, a substantially constant radial gap is formed between the teeth end surfaces 225 and the insulating member 3. Specifically, a gap of about 1 to 2 mm from the tooth end surface 225 was provided. In addition, there is almost no gap between the side surface of the tooth portion 22 facing the slot portion 25 (part of the slot inner wall surface 250) and the insulating member 3 in the vicinity of the projecting portion 229 on the tip end side of the tooth portion 22, A relatively large gap is provided on the base end side of the teeth portion 22, that is, on the slot inner side wall portion 252 near the slot bottom surface portion 251 of the slot inner wall surface 250. Specifically, the gap between the teeth portion 22 and the insulating member 3 is set to be approximately 0.2 to 0.3 mm in the slot inner side surface portion 252.
[0034]
In addition, as the synthetic resin, LCP (Liquid Crystal Polymer) was used. Then, the synthetic resin was filled in the mold. As a result, as shown in FIGS. 3 to 8, the synthetic resin is first removed from the yoke end surface 205 of the yoke portion 20 and the tooth end surface 225 of the tooth portion 22 facing both axial end surfaces of the stator core 2. At least a portion not covered by the insulating member 3 and the above-mentioned slot bottom surface portion 251 are covered to form the resin mold film 4.
[0035]
Further, in the slot inner side surface portion 252 near the base end portion of the tooth portion 22 of the slot inner wall surface 250, synthetic resin flows into the entire circumference between the tooth portion 22 and the insulating member 3, and the resin mold film 4 is formed. Thus, an overlap portion 5 where the resin mold film 4 and the insulating member 3 overlap was formed.
Further, between the tooth end surface 225 of the tooth portion 22 and the insulating member 3, the synthetic resin flowed not only to the base end side but also to the front end side, and the resin mold film 4 was formed. As a result, the resin mold film 4 was formed on the entire surface of the tooth end surface 225, and the entire surface of the insulating member 3 facing the tooth end surface 225 formed the overlap portion 5.
[0036]
FIGS. 4 to 8 illustrate the insulating structure 1 obtained by the above-described insulating method from the cross section of each part. These figures are explanatory diagrams in which a portion having a curvature is also shown linearly for convenience.
FIG. 4 is an explanatory diagram as viewed from above. FIG. 5 is a sectional view taken along line AA in FIG. FIG. 6 is a sectional view taken along line BB in FIG. FIG. 7 is a sectional view taken along line CC in FIG. FIG. 8 is a sectional view taken along line DD in FIG.
[0037]
As is known from the appearances shown in FIGS. 3 and 4, it can be seen that the axial end face of the stator core 2 is entirely covered with the resin mold film 4 or the insulating member 3.
Further, as is known from FIGS. 5 to 7, the side surface of the tooth portion 22 has an overlap portion where the resin mold film 4 and the insulating member 3 overlap on the base end side, that is, the portion of the slot inner side surface portion 252. 5 is formed, but it can be seen that only the insulating member 3 is covered on the tip end side. As shown in FIG. 5, the width W of the overlap portion 5 on the side surface of the tooth portion 22 in this example is about 4 mm in the radial direction.
[0038]
As shown in FIGS. 5 to 8, in each of the overlapping portions 5 in this example, the resin mold film 4 exists on the teeth portion 22 and the insulating member 3 is formed on the surface of the resin mold film 4. Has a double laminated structure.
[0039]
Next, the operation and effect of this embodiment will be described.
In the insulating structure of the stator core of the present embodiment, a portion of the stator core 2 to be insulated is covered with the insulating member 3 or the resin mold film 4. Therefore, it is possible to prevent direct contact between the coil 8 inserted into the slot 25 and the teeth 22 and the yoke 20.
[0040]
Further, in the present example, the resin mold film 4 is interposed between the insulating member 3 and the teeth portion 22 near the base end of the teeth portion 22 to form the overlap portion 5. Therefore, the creepage distance at the boundary between the insulating member 3 and the resin mold film 4 can be positively increased, and the generation of creepage current can be prevented. Further, the presence of the overlap portion 5 allows the insulating member 3 to sufficiently engage with the resin mold film 4 and prevent the insulating member 3 from being displaced.
[0041]
Further, since the periphery of the teeth portion 22 can be insulated by the insulating member 3, it is necessary to form the resin mold film 4 on the side surface of the teeth portion 22 facing the slot portion 25 (part of the slot inner wall surface 250). There is no. The resin mold film 4 may be formed only in the vicinity of the slot bottom surface portion 251 of the slot inner wall surface 250 where a relatively large thickness is allowed. Therefore, as described above, a method of forming the resin mold film 4 by applying the molding method after the insulating member 3 is mounted can be positively adopted. Therefore, even when the axial length of the stator core 3 is long, the above-described insulating structure 1 can be realized using the molding method.
[0042]
Furthermore, in this example, the resin mold film 4 is formed on the entire surface of the teeth end surface 225, and the entire surface of the insulating member 3 facing the tooth end surface 225 forms the overlap portion 5. Therefore, the insulating effect and the creeping current generation preventing effect can be further enhanced, and the increase in the overlap portion 5 can enhance the fixing effect of the insulating member.
[0043]
Example 2
In the present embodiment, as shown in FIG. 9, a through hole 36 as a notch is provided at both ends of the insulating member 3 in the first embodiment.
In this example, the through holes 36 were overlapped on one of the teeth end surfaces 252 to form an overlapped portion, and the above-described molding method was performed.
As a result, the resin mold film 4 filled in the above-described molding step flows into the through-hole 36 and exhibits the effect of joining the insulating member 3 at the overlapped portion. Therefore, the process can be further rationalized.
Otherwise, the same operation and effect as those of the first embodiment can be obtained.
[0044]
Example 3
In this example, as shown in FIGS. 10 to 12, the arrangement of the insulating member 3 and the resin mold film 4 of the overlap portion 5 is reversed, instead of the insulating structure in the first embodiment.
That is, as shown in the figure, in this example, in all of the overlap portions 5, the insulating member 3 is present on the teeth 22 and the resin mold film 4 is present on the insulating member 3. Adopted structure. Further, as in the first embodiment, the overlap portion 5 is formed only on the slot inner side surface portion 252 near the base end portion on the side surface side of the tooth portion 22, and the insulating member 3 is formed on the tooth end surface 225. Was formed on the entire surface in which is present. Others are the same as the first embodiment.
[0045]
In this case, in the insulating member arranging step at the time of manufacturing, the insulating member 3 is arranged around the teeth portion 22 with almost no gap, and the cavity is formed only in a desired portion by a mold used in the molding step. Once formed, it can be manufactured. Therefore, there is almost no need to control the size of the gap between the insulating member 3 and the teeth portion 22, and the manufacturing becomes easy. In addition, the same functions and effects as those of the first embodiment can be obtained.
[0046]
Example 4
In this example, as shown in FIGS. 13 and 14, the basic structure in Example 3 is followed, and the joining of the insulating member 3 on one tooth end surface 225 is performed by a cap member 33 which is another member. It is an example.
[0047]
First, as shown in the figure, the shape of the insulating member 3 of this example facing one tooth end surface 225 was changed. That is, a first bent piece 311 bent from the side surface portion 310 contacting the side surface of the tooth portion 22 to the tooth end surface 225 side, and a second bent piece bent continuously in the direction away from the tooth end surface 225. 312, and a third bent part 313 that is bent from the tip of the second bent part 312 toward the first bent part 311.
[0048]
The cap member 33 is a member having a substantially cup-shaped cross section and having an engaging portion 331 formed at an opening thereof by bending inward so as to reduce the opening diameter. The cap member 33 is made of the same material as the insulating member 3.
[0049]
In the present embodiment, after the insulating member 3 is wound around the teeth portion 22 in the insulating member disposing step, the cap member 33 is put on the third folded piece portion 331 and the engaging portion 331 is engaged. Then, the insulating member 3 is fixed. Then, a molding process is performed.
[0050]
Thus, as shown in FIGS. 13 and 14, on one tooth end surface 225 of the tooth portion 22, the resin mold film 4, the insulating member 3, and the cap 33 are laminated, and further, the resin mold film 4 is formed on the upper surface thereof. A laminated three-layer structure is obtained.
[0051]
In the case of this example, by using the cap 33, the work of fixing the insulating member 3 in the insulating member arranging step can be facilitated. Otherwise, the same operation and effect as those of the first embodiment can be obtained.
[0052]
Example 5
In this example, as shown in FIGS. 15 and 16, the basic structure in Example 3 is followed, and a resin part 61 made of synthetic resin is interposed between one tooth end surface 225 and the insulating member 3. This is an example.
As shown in the figure, the resin part 61 of this example has a bottom portion 610 that comes into contact with the tooth end surface 225 and an inverted tapered shape that is erected at the center thereof and whose width dimension increases as the distance from the bottom portion 610 increases. And a standing portion 611 that is provided. Further, an insertion hole 613 for inserting a pin 35 described later is formed in the upper surface 612 of the standing portion 611.
[0053]
In addition, as shown in the figure, the insulating member 3 of this example is bent from the side surface portion 320 contacting the side surface of the tooth portion 22 to the tooth end surface 225 along the surface of the bottom portion 610 of the resin part 61. A first bent piece 321, a second bent piece 322 connected to the first bent piece 321 and bent away from the teeth end surface 225, and further folded back from the tip of the second bent piece 322 in a direction in contact with the resin part 61. And a bent third bent portion 323.
[0054]
Further, in the present embodiment, as shown in the figure, a cap member 34 and a pin 35 having a substantially cup-shaped cross section are used.
The cap member 34 has a substantially cup shape in cross section so as to cover the second bent piece 323, and has a through hole 341 in the center of the bottom surface 340. Further, the pin 35 has a head 351 having a diameter larger than that of the pin main body 350, and the diameter of the pin main body 350 can be press-fitted into the insertion hole 613 of the resin part 61 and engaged therewith. It is designed to be.
[0055]
In the insulating member arranging step for obtaining the insulating structure of the present embodiment, before arranging the insulating member 3, a resin part 61 made of a synthetic resin is interposed on the teeth end surface 225, and thereafter, the insulating member 3 is formed. Is arranged. Then, after covering the cap member 34 so as to cover the second folded piece 322 of the insulating member 3, the pin 35 is inserted through the through hole 341 of the cap member 34 and pressed into the insertion hole 613 of the resin part 61. Thereby, the insulating member 3 can be fixed.
Further, in this fixing structure, the third folded piece 323 of the insulating member 3 is well engaged with the inverted tapered shape of the upright portion 611 of the resin part 61, and the fixing state can be further stabilized.
[0056]
Then, by performing the molding process in the same manner as in the first and second embodiments, the insulating structure of the present embodiment can be obtained.
In the case of this example, as described above, the insulating member 3 can be easily fixed in the insulating member arranging step, and the manufacturing process can be further streamlined.
Otherwise, the same operation and effect as those of the first embodiment can be obtained.
[0057]
Example 6
In this example, as shown in FIGS. 17 and 18, the resin part 62 whose shape is changed from the case of the fifth embodiment is employed, and the shape of the insulating member 3 and the shape of the cap member 33 are the same as those of the fourth embodiment. This is an example similar to.
As shown in the drawing, the resin part 62 of the present example has a bottom surface 620 that abuts on the tooth end surface 225 and a tapered shape that is erected at the center and the width decreases as the distance from the bottom surface 620 increases. Erected portion 621.
[0058]
In this case, in the insulating member disposing step, before disposing the insulating member 3, a resin part 62 made of a synthetic resin is interposed on the teeth end surface 225, and then the insulating member 3 is disposed. Then, the cap member 33 is covered so as to cover the third folded piece portion 313 of the insulating member 3, and the engaging portion 331 is engaged with the cap member 33. Thereby, the insulating member 3 can be fixed. At this time, in the present embodiment, the fixing structure can be more stabilized than in the fourth embodiment due to the presence of the resin part 62. In addition, the same functions and effects as those of the other embodiments described above can be obtained.
[0059]
Example 7
In the present embodiment, as shown in FIG. 19, the resin parts 62 of the sixth embodiment are arranged on both teeth end surfaces 225 of the teeth portion 22.
In this case, the shape of the insulating member 3 is changed to a substantially trapezoidal portion at a portion facing the tooth end surface 225 on the side opposite to the side where the cap member 33 is provided. More specifically, the shape has a flat portion 317 that contacts the tip end surface 622 of the resin part 62 and an inclined portion 316 that connects the side portion 310. Others are the same as the sixth embodiment.
[0060]
In this case, resin parts 62 having the same shape are respectively provided on the teeth end surfaces on both axial end surfaces of the stator core 2. For this reason, up to this point, the stator core can be handled at least in a state where the front and back are symmetrical, and the process management can be facilitated. Furthermore, since the synthetic resin of the resin mold film 4 enters between the resin part 62 and the insulating member 3, the bonding force between the synthetic resin and the insulating member can be increased, and the resin mold film 4 or the insulating member 3 Can be prevented from peeling off. Others are the same as the sixth embodiment.
[0061]
Example 8
As shown in FIGS. 20 and 21, this embodiment is an example in which a cap member 36 whose shape is changed from that of the sixth embodiment is employed.
That is, as shown in the figure, the cap member 36 has a substantially cup-shaped cross section, the engaging portion 361 has a claw portion 362 protruding inward at the tip thereof, and the tip of the third folded piece portion 313. It is configured to engage surface 314.
[0062]
The shape of the insulating member 3 is the same as that of the sixth embodiment, and the shape of the resin part 63 is basically the same as that of the sixth embodiment, except that the width of the upright portion 631 is slightly larger. Are different.
[0063]
In the case of this example, since the cap member 36 has the claw portion 362 as described above, the cap member 36 is engaged with the distal end surface 314 of the third folded piece portion 313 of the insulating member 3 so that the insulating member 3 is formed. Can be further strengthened.
In addition, the same operation and effect as those of the other embodiments described above can be obtained.
[0064]
Example 9
In this example, as shown in FIG. 21, the resin parts 63 of the eighth embodiment are arranged on both tooth end surfaces 225 of the teeth portion 22.
Also in this case, the shape of the insulating member 3 is such that the flat portion 317 that contacts the tip end surface 632 of the resin part 63 at the portion facing the tooth end surface 225 opposite to the side where the cap member 36 is disposed, and the side surface And a slope portion 316 connecting the portion 310 and the portion 310. Others are the same as the eighth embodiment.
[0065]
Also in this case, the resin parts 63 having the same shape are provided on the teeth end surfaces at both axial end surfaces of the stator core 2, so that up to this point, the stator core can be handled at least in a front-back state, and the process management can be performed. Can be facilitated. Further, since the synthetic resin of the resin mold film 4 enters between the resin part 63 and the insulating member 3, the bonding force between the synthetic resin and the insulating member can be increased, and the resin mold film 4 or the insulating member 3 Can be prevented from peeling off. In addition, the same functions and effects as those of the above-described embodiment can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a structure of a stator core according to a first embodiment.
FIG. 2 is an explanatory diagram illustrating a completed state of an insulating member disposing step in the first embodiment.
FIG. 3 is an explanatory view showing an insulating structure of a stator core in the first embodiment.
FIG. 4 is an explanatory view of the insulating structure of the stator core according to the first embodiment as viewed from the top (end face side).
FIG. 5 is a cross-sectional view (a cross-sectional view taken along line AA in FIG. 3) of the first embodiment viewed from a cross-section along a lamination surface of the stator core;
FIG. 6 is a vertical cross-sectional view (a cross-sectional view taken along line BB in FIG. 4) of the stator core in the vicinity of a slot open portion of the teeth portion according to the first embodiment when viewed from a circumferential cross-section of the stator core;
FIG. 7 is a vertical cross-sectional view (a cross-sectional view taken along line CC in FIG. 4) of the stator core in the vicinity of the base end portion of the tooth portion in the first embodiment viewed from the circumferential cross section of the stator core;
FIG. 8 is a vertical cross-sectional view (a cross-sectional view taken along line DD in FIG. 4) of the teeth in Example 1 as viewed from a radial cross-section parallel to the axial direction of the stator core.
FIG. 9 is an explanatory view showing a through hole as a cutout portion of the insulating member in the second embodiment.
FIG. 10 is a cross-sectional view (corresponding to a cross-sectional view taken along the line AA in FIG. 3) of the third embodiment as viewed from a cross section along the lamination surface of the stator core.
11 is a longitudinal sectional view (corresponding to a sectional view taken along line BB of FIG. 4) of the stator core in the vicinity of a slot open portion of the teeth portion in Example 3 as viewed from a circumferential section.
FIG. 12 is a longitudinal sectional view (corresponding to a sectional view taken along line CC in FIG. 4) of the stator core in the vicinity of the base end of the teeth portion in Example 3 as viewed from the circumferential section of the stator core;
FIG. 13 is a longitudinal sectional view (corresponding to a sectional view taken along line BB of FIG. 4) of the stator core in the vicinity of the slot open portion of the teeth portion in Example 4 as viewed from the circumferential section of the stator core.
FIG. 14 is a longitudinal sectional view (corresponding to a sectional view taken along line CC in FIG. 4) of the stator core in the vicinity of the base end portion of the teeth portion in Example 4 as viewed from the circumferential section of the stator core.
FIG. 15 is a longitudinal sectional view (corresponding to a sectional view taken along line BB of FIG. 4) of the stator core in the vicinity of the slot open portion of the tooth portion in Example 5 as viewed from the circumferential section of the stator core.
FIG. 16 is a longitudinal sectional view (corresponding to a sectional view taken along line CC of FIG. 4) of the stator core in the vicinity of the base end portion of the tooth portion in Example 5, viewed from the circumferential section of the stator core.
FIG. 17 is a vertical cross-sectional view (corresponding to a cross-sectional view taken along line BB of FIG. 4) of the stator core in the vicinity of the slot open portion of the teeth portion in Example 6 as viewed from the circumferential cross-section of the stator core.
FIG. 18 is a vertical cross-sectional view (corresponding to a cross-sectional view taken along line CC in FIG. 4) of the vicinity of the base end of the teeth in Example 6 viewed from a circumferential cross-section of the stator core.
FIG. 19 is a vertical cross-sectional view (corresponding to a cross-sectional view taken along line BB of FIG. 4) of the stator core in the vicinity of the slot open portion of the tooth portion in Example 7 as viewed from the circumferential cross section of the stator core.
FIG. 20 is a vertical cross-sectional view (corresponding to a cross-sectional view taken along line BB in FIG. 4) of the stator core in the vicinity of the slot open portion of the teeth portion in Example 8 as viewed from the circumferential cross section of the stator core;
FIG. 21 is a longitudinal sectional view (corresponding to a sectional view taken along line CC of FIG. 4) of the stator core in the vicinity of the base end of the tooth portion in Example 8 as viewed from the circumferential section of the stator core.
FIG. 22 is a vertical cross-sectional view (corresponding to a cross-sectional view taken along line BB of FIG. 4) of the stator core in the vicinity of a slot open portion of the teeth portion in Example 9 as viewed from a circumferential cross-section;
[Explanation of symbols]
1. . . Stator core insulation structure,
2. . . Stator core,
20. . . Yoke,
22. . . Teeth part,
25. . . Slot part,
3. . . Insulating material,
4. . . Resin mold film,
5. . . Overlap part,

Claims

A stator core having a ring-shaped yoke, a plurality of teeth protruding radially inward from the yoke as a base end, and a slot formed between the teeth, for obtaining electrical insulation of a stator core. In the insulation structure,
The teeth portion is provided with an insulating member having electrical insulation so as to cover at least a part of the teeth.
Further, at least a part of the yoke end surface of the yoke portion facing the axial both end surfaces of the stator core and at least the insulating portion of the tooth end surface of the tooth portion facing the axial end surfaces of the stator core. A resin mold film made of a synthetic resin is formed on the portion not covered by the member and on the slot bottom surface located radially outward of the insulating member on the slot inner wall surface facing the slot portion. Yes,
An insulation structure for a stator core, wherein an overlap portion in which the resin mold film and the insulation member overlap with each other is formed at least in the vicinity of the base end of the teeth portion over the entire periphery of the teeth portion. .

2. The tooth end surface according to claim 1, wherein the resin mold film is formed on the tooth end surface and / or on the insulating member over the entire surface thereof, and the entire surface of the insulating member facing the tooth end surface is provided. Forming the above-mentioned overlapping portion.

3. The double lamination according to claim 1, wherein at least a part of the overlap portion has the resin mold film on the teeth portion and the insulating member exists on a surface of the resin mold film. An insulation structure for a stator core, characterized by having a structure.

4. The method according to claim 1, wherein at least a part of the overlap portion has the insulating member on the teeth portion and the resin mold film on the insulating member. An insulation structure for a stator core, which has a multilayer structure.

The stator core insulating structure according to any one of claims 1 to 4, wherein a resin part made of a synthetic resin is interposed between the teeth end surface and the insulating member.

The stator core insulating structure according to any one of claims 1 to 5, wherein the insulating member has an overlapping portion on at least one of the teeth end surfaces.

7. The stator core insulating structure according to claim 6, wherein the insulating member is joined at the overlapping portion.

The insulating member according to any one of claims 1 to 8, wherein the insulating member has a notch or a protrusion at the overlap portion, and the notch or the protrusion is engaged with the resin mold film. An insulating structure for a stator core, wherein the insulating member is fixed by forming a state.

The stator core insulating structure according to any one of claims 1 to 9, wherein the overlap portion is formed at least 4 mm or more in a radial direction of the stator core.

A stator core having a ring-shaped yoke, a plurality of teeth projecting radially inward from the yoke as a base end, and a slot formed between the teeth, for obtaining electrical insulation of a stator core. In the insulation method,
An insulating member arranging step of arranging an insulating member having electrical insulation so as to cover substantially the entire periphery of at least a part of the teeth portion;
Performing a molding step of setting the stator core in a mold, pouring a synthetic resin into the mold, and forming a resin mold film on at least a part of the surface of the stator core;
In the molding step, at least a part of the yoke end surface of the yoke portion facing the axial both end surfaces of the stator core and the tooth end of the tooth portion facing the axial end surfaces of the stator core. The resin mold film is formed on at least a portion of the surface that is not covered by the insulating member and a slot bottom surface portion of the slot inner wall surface facing the slot portion that is located radially outward from the insulating member. Along with
At least in the vicinity of the base end of the teeth, between the teeth and the insulating member and / or by flowing the synthetic resin onto the surface of the insulating member to form the resin mold film,
A method for insulating a stator core, comprising: forming an overlap portion where the resin mold film and the insulating member overlap each other at least in the vicinity of a base end of the tooth portion over the entire circumference of the tooth portion.

11. The resin molding film according to claim 10, wherein in the molding step, the synthetic resin is caused to flow into the gap between the tooth end surface and the insulating member facing the tooth end surface and / or the entire surface of the insulating member. A method for insulating a stator core, comprising:

12. The stator core insulation structure according to claim 10, wherein in the insulating member disposing step, a resin part made of a synthetic resin is interposed on the teeth end surfaces, and then the insulating member is disposed. .