JP4043659B2

JP4043659B2 - Method for manufacturing self-starting permanent magnet type synchronous motor

Info

Publication number: JP4043659B2
Application number: JP25703599A
Authority: JP
Inventors: 健治佐々木; 輝雄田村; 三千寛吉田
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1999-09-10
Filing date: 1999-09-10
Publication date: 2008-02-06
Anticipated expiration: 2019-09-10
Also published as: JP2001086675A

Description

【０００１】
【発明の属する技術分野】
本発明は、冷凍冷蔵機器用および空調機器用の電動圧縮機や一般産業用に使用される自己始動形永久磁石式同期電動機に関する。
【０００２】
【従来の技術】
自己始動形永久磁石式同期電動機は始動時には回転子の始動用かご形導体により誘導電動機として作動し、回転子が同期速度付近に達すると永久磁石による回転子磁極が回転子巻線のつくる同期速度で回る回転磁界に引き込まれて同期運転を行うものであるが、定速度運転性および高効率性等優れた性能を有している。特に電動機の回転子構造についてはさまざまな改良が施されてきた。
【０００３】
従来の自己始動形永久磁石式同期電動機の回転子の一例は特開平９−３０８１９５号公報に示されているものがある。以下、図８から図１０を参照しながら上記従来の自己始動形永久磁石式同期電動機の回転子について説明する。
【０００４】
図８は回転子の径方向断面図であり、図９は回転子の軸方向断面図である。また図１０は図８のＡ部の部分拡大図である。図８から図１０において、１は回転子、２は積層電磁鋼板よりなる回転子鉄心である。３は導体バーであり、回転子鉄心２の両端に位置する短絡環４とアルミダイカストで一体的に成型されて始動用かご形導体を形成している。また、５は永久磁石であり、回転子鉄心２の軸方向に設けた永久磁石埋設穴６に同極性の２個の永久磁石５を回転子鉄心２のブリッジ部７を挟んで山形状に突き合わせるように配置して一つの回転子磁極を作り、回転子全体では４極の回転子磁極を形成している。
【０００５】
また、隣り合う異極性の２個の永久磁石５はお互いに山形状に直接突き合わせて配置されており両者の永久磁石５の間には回転子鉄心のブリッジ部は設けられていない。
【０００６】
８は永久磁石保護用の非磁性の端板である。９は回転子１の軸穴であり、１０は回転子１に装着された軸である。
【０００７】
また、従来例の製造方法は、回転子鉄心２に永久磁石５を挿入し、且つ端板を回転子鉄心に当接させた後に、アルミダイカストにより始動用かご形導体を形成するとともに、端板も同時に一体的に回転子鉄心２に固定するという製造方法となっている。
【０００８】
【発明が解決しようとする課題】
しかしながら上記従来の構成では、同極性の永久磁石５間のブリッジ部７は図８のＡ部に示されているように永久磁石５の突き合わせ端面と当接しているかまたは微小な隙間しか設けられていない。このことにより、図１０に示すように永久磁石５の端面５ａ内における異極間の磁束短絡が多くなって永久磁石５による回転子磁極の強さは弱くなる。そのため、電動機は脱調トルクが低下し、且つ電流が増大して電動機の性能が低下するという課題があった。
【０００９】
また隣り合う異極性の２個の永久磁石５の間には回転子鉄心２のブリッジ部が設けられておらず、回転子鉄心２の永久磁石埋設穴６の外側部分と内側部分とはブリッジ部７のみでつながっており強度的に弱いという欠点があった。
【００１０】
また始動用かご形導体をアルミダイカストで形成した後、短絡環４が冷えて内側に収縮する際に、回転子鉄心２の軸方向の両端部もその応力を受けて内側に収縮しようとする。その際２個の異極の永久磁石５の突き合わせ箇所付近ではブリッジ部が設けられていないので、永久磁石埋設穴６の径方向の幅が縮んでアルミダイカスト前に挿入した永久磁石５との隙間がなくなり、回転子鉄心の外径寸法が小さくなる。
【００１１】
一方ブリッジ部７付近の永久磁石埋設穴６の径方向の幅は、アルミダイカストによってもブリッジ部７が収縮応力を支えるため殆ど変化せず、回転子鉄心２の外径寸法も変わらない。このように、回転子鉄心２の外径は箇所によって異なる寸法となるため、固定子鉄心内径との空隙寸法を回転子鉄心２の電磁鋼板を金型打抜きするだけで形成しようとしても精度よく出すことができず、アルミダイカスト後回転子鉄心２の外径切削を行う必要があり工数がかかるという課題があった。
【００１２】
また回転子鉄心２に永久磁石５を挿入し、且つ端板８を回転子鉄心２に当接させた後アルミダイカストをする製造方法であるので、アルミダイカスト作業が複雑になり不良品が出易いという課題があった。
【００１３】
本発明は上記の課題に鑑み、回転子鉄心２内の磁束短絡を防止するとともに、回転子鉄心２の外径切削を不要とし、且つアルミダイカスト作業を容易にした生産性の高い製造方法とし、高性能で安価な自己始動形永久磁石式同期電動機を提供することを目的とする。
【００１４】
【課題を解決するための手段】
この目的を達成するために本発明は、固定子鉄心に巻線を巻装した固定子と、前記固定子鉄心の内径円筒面に対向して自在に回転し、回転子鉄心の外周付近に位置する複数個の導体バーと前記回転子鉄心の軸方向の両端面に位置する短絡環とをアルミダイカストで一体成型して始動用かご形導体を形成するとともに、前記導体バーの内側に複数個の永久磁石を埋設した回転子とからなる２極の自己始動形永久磁石式同期電動機の製造方法において、前記永久磁石を埋設する永久磁石埋設穴を回転子鉄心の径方向に設けた幅が狭い部分と広い部分とを有するブリッジ部Ｆを挟んで山形状に突き合わせるように配置し、これに同極性の永久磁石を埋設することにより一つの回転子磁極を形成させ、かつ前記永久磁石の端面と前記ブリッジ部Ｆとの間に磁束短絡防止用の空間部を設けるとともに、隣り合う異極性の永久磁石を埋設する永久磁石埋設穴の間には磁束短絡防止用のバリアスロットを挟んで回転子鉄心の径方向に２箇所のブリッジ部Ｇを設けて、前記回転子鉄心の外径を回転子磁極の端部から中心部に向かうにつれて次第に大きくなるような楕円形状に形成した回転子鉄心に、アルミダイカストにより始動用かご形導体を形成した後、永久磁石を装着することを特徴とする製造方法である。同極性の永久磁石を回転子鉄心の幅の狭い部分と広い部分とを有する径方向のブリッジ部を挟んで山形状に突き合わせるように配置するとともに、永久磁石の端面とブリッジ部との間に磁束短絡防止用の空間部を設ける構成としたので、永久磁石の端面内における異極間の磁束短絡を防止して電動機の性能を向上させることができ、且つアルミダイカスト後の短絡環の径方向の収縮による回転子鉄心外径の回転子磁極中心での収縮歪を、ブリッジ部の強度を強くしたために微小にすることができるので、固定子鉄心内径との間の空隙寸法を回転子鉄心の電磁鋼板を金型打抜きするだけで精度よく出すことができ、回転子鉄心の外径を切削することが不要となって、工数を低減することができる。
【００１５】
また本発明は同極性の永久磁石を回転子鉄心に設けた２箇所のブリッジを挟んで配置する構成としたので、アルミダイカスト後の回転子鉄心の回転子磁極の中心付近の外径の収縮歪はさらに低減され、固定子鉄心内径との空隙寸法をより精度よく出すことができる。
【００１６】
なお、永久磁石回転子の永久磁石埋設穴と永久磁石との径方向の隙間を回転子磁極の端部から中心部に向かうにつれて次第に大きくなるように形成した回転子鉄心に、アルミダイカストで始動用かご形導体を形成した後、永久磁石を装着する製造方法としたので、アルミダイカスト後の回転子鉄心の外径の径方向の収縮歪が回転子磁極の中心付近に向かうにつれて大きくなっても、永久磁石との間の隙間は十分確保でき、永久磁石を支障なく容易に永久磁石埋設穴に挿入することができる。またアルミダイカストは永久磁石や端板がない状態で行うので作業が簡単になる。
【００１７】
このように、本発明は２極の永久磁石回転子において、回転子鉄心の外径を回転子磁極の端部から中心部に向けて次第に大きくなるような楕円形状に形成し、その回転子鉄心にアルミダイカストで始動用かご形導体を形成した後、永久磁石を装着する製造方法としたので、アルミダイカスト後の回転子鉄心外径の径方向の収縮歪が回転子磁極の中心付近に向かうにつれて大きくなっても、収縮後の回転子鉄心の外径をほぼ真円にすることができるので、回転子鉄心の電磁鋼板を金型打抜きするだけで固定子鉄心内径との空隙寸法を精度よく出すことができ、回転子鉄心の外径切削は不要となって工数を低減することができる。またアルミダイカストは永久磁石や端板がない状態で行うので作業が簡単で不良品が出にくくなり、生産性を高めることができる。
【００１８】
また本発明は永久磁石を希土類磁石で形成したものであるため、強い磁力が得られるので回転子や電動機全体を小型軽量化することができる。
【００１９】
なお、固定子鉄心に巻線を巻装した固定子と、前記固定子鉄心の内径円筒面に対向して自在に回転し、回転子鉄心の外周付近に位置する複数個の導体バーと前記回転子鉄心の軸方向の両端面に位置する短絡環とをアルミダイカストで一体成型して始動用かご形導体を形成するとともに、前記導体バーの内側に複数個の永久磁石を埋設した回転子とからなる電動機であって、永久磁石埋設穴を回転子鉄心の径方向に設けた幅が狭い部分と広い部分とを有するブリッジ部Ａを挟んで山形状に突き合わせるように配置し、これに同極性の永久磁石を埋設することにより一つの回転子磁極を形成させ、且つ前記永久磁石の端面と前記ブリッジ部Ａとの間に磁束短絡防止用の空間部を設けるとともに、隣り合う異極性の永久磁石を埋設する永久磁石埋設穴の間には磁束短絡防止用のバリアスロットを挟んで回転子鉄心の径方向に２箇所のブリッジ部Ｂを設けたことにより、永久磁石端面内の磁束短絡を防いで電動機の性能を向上でき、且つアルミダイカスト後の回転子鉄心外径の径方向の収縮歪は微小となり、電磁鋼板の金型打抜きだけで固定子鉄心内径との空隙寸法を精度よく出すことができるので、回転子鉄心の外径切削が不要となって工数を低減することができるという作用を有する。
【００２０】
なお、固定子鉄心に巻線を巻装した固定子と、前記固定子鉄心の内径円筒面に対向して自在に回転し、回転子鉄心の外周付近に位置する複数個の導体バーと前記回転子鉄心の軸方向の両端面に位置する短絡環とをアルミダイカストで一体成型して始動用かご形導体を形成するとともに、前記導体バーの内側に複数個の永久磁石を埋設した回転子とからなる電動機であって、永久磁石埋設穴を回転子鉄心の径方向に設けた２箇所のブリッジ部Ｃを挟んで山形状に突き合わせるように配置し、これに同極性の永久磁石を埋設することにより一つの回転子磁極を形成させ、且つ前記永久磁石の端面と前記ブリッジ部Ｃとの間に磁束短絡防止用の空間部を設けるとともに、隣り合う異極性の永久磁石を埋設する永久磁石埋設穴の間には磁束短絡防止用のバリアスロットを挟んで回転子鉄心の径方向に２箇所のブリッジ部Ｂを設けたことにより、回転子磁極の中心部における回転子鉄心外径の径方向の収縮歪はさらに低減され、固定子鉄心内径との空隙寸法をより精度よく出すことができるので電動機のさらなる低騒音・低振動化を図ることができるという作用を有する。
【００２１】
なお、固定子鉄心に巻線を巻装した固定子と、前記固定子鉄心の内径円筒面に対向して自在に回転し、回転子鉄心の外周付近に位置する複数個の導体バーと前記回転子鉄心の軸方向の両端面に位置する短絡環とをアルミダイカストで一体成型して始動用かご形導体を形成するとともに、前記導体バーの内側に複数個の永久磁石を埋設した回転子とからなる２極の自己始動形永久磁石式同期電動機において、永久磁石埋設穴を永久磁石との径方向の隙間が回転子磁極の端部から中心部に向かうにつれて次第に大きくなるように形成した回転子鉄心に、アルミダイカストにより始動用かご形導体を形成した後、永久磁石を装着する製造方法としたものであり、アルミダイカストにより永久磁石埋設穴の径方向の幅が狭くなるが、回転子鉄心への永久磁石の挿入は支障なく容易に行えるとともに、アルミダイカスト作業が簡単になるという作用を有する。
【００２２】
【発明の実施の形態】
本発明は、固定子鉄心に巻線を巻装した固定子と、前記固定子鉄心の内径円筒面に対向して自在に回転し、回転子鉄心の外周付近に位置する複数個の導体バーと前記回転子の軸方向の両端面に位置する短絡環とをアルミダイカストで一体成型して始動用かご形導体を形成するとともに、前記導体バーの内側に複数個の永久磁石を埋設した回転子とからなる２極の自己始動形永久磁石式同期電動機において、回転子鉄心の外径を回転子磁極の端部から中心部に向かうにつれて次第に大きくなるような楕円形状に形成した回転子鉄心に、アルミダイカストにより始動用かご形導体を形成した後、永久磁石を装着する製造方法としたものであり、アルミダイカストによる回転子鉄心外径の径方向の収縮歪があっても、回転子鉄心内径との空隙寸法は電磁鋼板の金型打抜きだけで精度よく出すことができるので回転子鉄心の外径切削は不要となり、且つアルミダイカスト作業が簡単になって生産性を高めることができるという作用を有する。
【００２３】
なお、上記において永久磁石を希土類磁石で形成すると、強い磁力が得られ、回転子や電動機全体を小型軽量化することができるという作用を有する。
【００２４】
【実施例】
以下、本発明による自己始動形永久磁石式同期電動機とその製造方法の実施例について図面を参照しながら説明する。なお、参考例についても説明する。同一の構成については同一の符号を付して詳細な説明は省略する。また固定子は一般的な自己始動形永久磁石式同期電動機と同様の構成であるため固定子についての説明も省略する。
【００２５】
（参考例１）
図１から図３を用いて説明する。図１は参考例１による自己始動形永久磁石式同期電動機の回転子の軸方向断面図であり、図２は図１の径方向断面図である。また図３は図２のＭ部の部分拡大図である。
【００２６】
図１から図３において、１は回転子、２は積層電磁鋼板よりなる回転子鉄心である。３は導体バーであり、回転子鉄心２の軸方向の両端に位置する短絡環４とアルミダイカストで一体成型されて始動用かご形導体を形成している。また５は永久磁石であり、回転子鉄心２の軸方向に設けた永久磁石埋設穴６に、同極性の２個の平板状の永久磁石５を回転子鉄心２のブリッジ部Ａ７を挟んで山形状に突き合わせるように配置して一つの回転子磁極を作り、回転子全体では２極の回転子磁極を形成している。
【００２７】
ここで７のブリッジ部Ａは幅の狭い部分７ａと７ａから外径側に向かうにつれて幅を広くした部分７ｂとをもつように設計されている。永久磁石５の裏表の異極間の磁束短絡は、幅の狭い部分７ａが磁気飽和することによって防止される。
【００２８】
また永久磁石５の端面５ａとブリッジ部Ａ７との間には空間部８が設けられているので、永久磁石５の端面５ａ内における異極間の磁束短絡を防ぐことができる。
【００２９】
また９は隣り合う異極性の永久磁石５の間に設けた磁束短絡防止用のバリアスロットであり、その中はアルミダイカストでアルミ１０が充填されている。バリアスロット９と永久磁石埋設穴６との間の回転子鉄心２のブリッジ部Ｂ１１は狭い幅に設定されており、この部分が磁気飽和して異極性どうしの永久磁石５の間の磁束短絡を防止するようになっており、且つ永久磁石５の端面とブリッジ部Ｂ１１の間には空間部１２を設けて、永久磁石５の端面内における異極間の磁束短絡を防止している。１３は永久磁石５を保護するための非磁性の端板であり、リベットピン１４により回転子鉄心２の両端面に固定されている。また１５は回転子の軸穴である。
【００３０】
以上のような構成の回転子１の製造は、電磁鋼板を積層してなる回転子鉄心２にアルミダイカストによって始動用かご形導体を形成した後、永久磁石埋設穴６に永久磁石５を埋設し、リベットピン１４で端板１３を回転子鉄心２の両端面に固定する順序をとる。
【００３１】
ここでアルミダイカストを行った後、アルミが冷却していく際に短絡環が径方向に収縮していくが、それに伴って回転子鉄心２も内径方向に収縮応力を受けることになる。しかしながら図２に示すようにバリアスロット９の付近は回転子鉄心２のブリッジ部Ｂ１１がバリアスロット９を挟んで２箇所設けられているため収縮応力に対する強度が強いので回転子鉄心２の外径の径方向の収縮歪は小さい。
【００３２】
一方ブリッジ部Ａ７は１箇所だけであるので、この部分での回転子鉄心２の内径方向への歪は大きくなる。そこでこれを防ぐためブリッジ部Ａ７の磁気飽和により磁束短絡を防ぐ幅の狭い部分７ａの径方向の長さを短くして、これに続く幅の広い部分７ｂを設けることにより、ブリッジ部Ａ７全体の径方向への収縮応力に対する強度を強くして、ブリッジ部Ａ７付近での回転子鉄心２の内径方向に歪が生じるのを防止している。
【００３３】
このことにより、回転子鉄心２の外径はほぼ真円に近い形状が確保できるので、回転子鉄心２の電磁鋼板を金型打抜きする際に、その外径をあらかじめ回転子鉄心内径との空隙が所定の寸法を得られるようにしておけば、アルミダイカスト後回転子鉄心外径を切削して所定の空隙寸法を出すという工程を省くことができる。
【００３４】
なお参考例では２極の回転子の例をとって説明したが、これに限られるものではなく４極等他の回転子磁極数のものであってもよい。
【００３５】
また永久磁石を平板状のもので説明したが、円弧状等他の形状のものであってもよい。
【００３６】
以上のように参考例１によれば永久磁石間の磁束短絡が防止されて高い性能を確保できるとともに、回転子鉄心の外径切削が不要となり、高性能で安価な自己始動形永久磁石式同期電動機を提供することができる。
【００３７】
（参考例２）
図４を用いて説明する。図４は参考例２による自己始動形永久磁石式同期電動機の回転子の径方向断面図である。
【００３８】
図４において、２１は回転子鉄心２のブリッジ部Ｃであり、同極性の２個の平板状の永久磁石５は２箇所のブリッジ部Ｃ２１を挟んで山形状に突き合わせるように配置されて一つの回転子磁極を作り、回転子全体では２極の回転子磁極を形成している。２２は２箇所のブリッジ部Ｃ２１の間の空間部であり、ブリッジ部Ｃ２１の幅を狭くして永久磁石５の裏表の異極間の磁束短絡を防止するように設計されている。
【００３９】
また２３は永久磁石５の端面とブリッジ部Ｃ２１との間に設けた空間部であり、参考例１の場合と同様に永久磁石５の端面内の異極間の磁束短絡を防止している。
【００４０】
以上の構成により、アルミダイカスト後の短絡環の径方向の収縮に伴う回転子鉄心２のブリッジ部Ｃ２１の付近の径方向の収縮歪は、ブリッジ部Ｃが２箇所設けられているため前記した参考例１の１箇所のブリッジ部の場合に比べて強度が強くなるので殆ど生じなくなり、アルミダイカスト後の回転子鉄心２の外径はさらに真円度が向上して回転子鉄心内径との空隙寸法を均一化でき、電動機のさらなる低騒音・低振動化を図ることができる。
【００４１】
（参考例３）
図５および図６を用いて説明する。
【００４２】
図５は参考例３による自己始動形永久磁石式同期電動機の回転子の電磁鋼板の平面図である。また図６は参考例３における他の回転子の電磁鋼板の平面図である。
【００４３】
図５において、３１は電磁鋼板であり、これが所定枚数積層されて回転子鉄心を形成した後、アルミダイカストによって始動用かご形導体が回転子鉄心に形成される。３２は始動用かご形導体の導体バーが充填される導体バー用スロットであり、３３は永久磁石埋設穴である。
【００４４】
上記２個の永久磁石３３にはアルミダイカスト後、２点鎖線で示すように同極性の２個の永久磁石が埋設されて一つの回転子磁極を形成する。また下部２個の永久磁石埋設穴３３にも異極性の永久磁石が埋設され、回転子全体では２極の回転子磁極を構成させることになる。３４はブリッジ部Ｄであり、この幅を狭くして磁気飽和を起こさせ永久磁石の裏表異極間の磁気短絡を防止するようにしてある。また３５は磁束短絡防止用のバリアスロットであり、上下の隣り合う永久磁石埋設穴３３の間に介在させるとともに、永久磁石埋設穴３３との間に形成させる２箇所のブリッジ部Ｅ３６の幅を狭く設定して、この部分を磁気飽和させて隣り合う異極性の永久磁石間の磁束短絡を防いでいる。３７は端板固定用のリベットピンを通すための穴であり、３８は軸穴である。
【００４５】
ここで永久磁石埋設穴３３の径方向の穴幅は、回転子磁極の端部（すなわちバリアスロット３６の付近）では永久磁石埋設穴３３と２点鎖線で示す永久磁石との隙間Ｐ₁を小さくし、回転子磁極の中心部（すなわちブリッジ部Ｄ３４の付近）に向かうにつれて隙間を次第に大きくして行き、Ｐ₂（Ｐ₂＞Ｐ₁）に到るよう
に設定する。
【００４６】
なお図面では理解しやすいように隙間を誇張して大きく描いている。
【００４７】
以上のような形状の電磁鋼板を金型で打抜き所定枚数積層して回転子鉄心を形成し、これにアルミダイカストにより始動用かご形導体を形成した後、永久磁石を装着する。回転子はアルミダイカスト後、始動用かご形導体の回転子鉄心の軸方向両端に形成した短絡環（図示せず）が冷えてきて径方向に収縮するが、それに伴い回転子鉄心の外径も短絡環の収縮応力を受けて径方向に収縮することになる。その際永久磁石埋設穴３３は、回転子磁極端部では２箇所のブリッジ部Ｅ３６があるため強度が強く殆ど穴幅が変化しないが、磁極中心部ではブリッジ部３５が１箇所だけであるため収縮応力に対して強度が弱く、永久磁石の穴幅は狭くなる。しかしながら永久磁石埋設穴３３の磁極中心部では永久磁石との隙間を大きくとった形状の電磁鋼板としているため、この箇所の穴幅が狭くなりすぎて永久磁石が挿入できなくなるといったことは起こらず、回転子の組み立てをスムースに行うことができる。
【００４８】
なお図６では同極性の平板状の２個の永久磁石で一つの回転子磁極を形成したが、平板状の永久磁石を３個以上使用して一つの回転子磁極を形成させてもよく、また永久磁石の形状は円弧状等他の形状としてもよい。
【００４９】
また図６は２点鎖線で示すような１個の円弧状の永久磁石だけで一つの回転子磁極をつくり、回転子全体では２個の円弧状の永久磁石で２極の回転子磁極を形成するような回転子鉄心の電磁鋼板である。個々の符号の説明は省略するが図５で述べたと同様に、回転子磁極の端部では永久磁石埋設穴４３と永久磁石との隙間Ｑ₁を狭くし、回転子磁極の中心部では、隙間Ｑ₂（Ｑ₂＞Ｑ₁）を広く設定するので、図５の例と同様の効果を得ることができる。
【００５０】
また参考例では、アルミダイカストは永久磁石や端板を装着しない状態で行うので作業が簡単で不良品もでにくくなって、生産性を向上させることができる。
【００５１】
（実施例１）
図７を用いて説明する。
【００５２】
図７は本発明の実施例１による自己始動形永久磁石式同期電動機の回転子の電磁鋼板の平面図である。
【００５３】
図７において５１は電磁鋼板であり、これが所定枚数積層されて回転子鉄心を形成した後、アルミダイカストによって始動用かご形導体が回転子鉄心に形成される。５２は導体バー用のスロットであり、５３は永久磁石埋設穴、５４はブリッジ部Ｆ、５５は磁束短絡防止用のバリアスロット、５６はブリッジ部Ｇである。また５７は端板固定用のリベットを通す穴であり、５８は軸穴である。各々の部分は前記した参考例３の場合と同様の役目を担うものであり重複を避けるため説明は省略する。また２点鎖線でアルミダイカスト後挿入する永久磁石を示しており、回転子は２極の回転子磁極を形成する。
【００５４】
ここで電磁鋼板５１の外径は、回転子磁極の端部では固定子鉄心内径との間に所定の空隙寸法になるような外径Ｒ₁に設定し、回転子磁極の中心部に向かうにつれて外径寸法を大きくしていき、回転子磁極の中心部の外径はＲ₂（Ｒ₂＞Ｒ₁）に到るように設定する。以上のような形状の電磁鋼板を打抜き、所定枚数積層して回転子鉄心を形成し、これにアルミダイカストにより始動用かご形導体を形成した後、永久磁石を装着する。
【００５５】
アルミダイカスト後、始動用かご形導体の回転子鉄心の軸方向両端面に形成した短絡環（図示せず）が冷えてきて径方向に収縮するが、それに伴い回転子鉄心の外径も短絡環の収縮応力を受けて径方向に収縮することになる。
【００５６】
その際回転子鉄心の電磁鋼板５１の回転子磁極端部はブリッジ部Ｇ５６が２箇所あるため、内径方向への収縮応力に対して強度が強いので回転子鉄心の外径Ｒ₁は殆ど変化しない。しかし回転子磁極の中心部ではブリッジ部Ｆ５４が１箇所あるだけなので、強度が弱く回転子鉄心の外径Ｒ₂は収縮応力を受けて径方向に収縮する。このとき外径Ｒ₂の寸法を収縮後の寸法がＲ₁になるように設定しておけば、回転子鉄心の外径全体は直径がＲ₁のほぼ真円の形状とすることができる。
【００５７】
なお図７において、収縮後の外径Ｒ₁の円は２点鎖線で示してあるが、Ｒ₁とＲ₂の寸法差は理解しやすいように誇張して大きくとって描いてある。
【００５８】
また図７では同極性の２個の平板状の永久磁石で一つの回転子磁極を形成したが、前記した図６に示すように１個の円弧状の永久磁石で一つの回転子磁極を形成させてもよい。
【００５９】
以上のように本発明によれば、アルミダイカスト後の回転子鉄心の外径はほぼ真円になるので、固定子鉄心内径との空隙はあらかじめ打抜き金型で打抜いて形成できるので、回転子鉄心の外径を切削して寸法出しをする必要はなく工数を低減することができる。
【００６０】
またアルミダイカストは永久磁石や端板を装着していない状態で行うので作業が簡単で不良品が出にくくなり、両者相俟って生産性を向上させることができる。
【００６１】
（参考例４）
図示はしないが、永久磁石をネオジウム・鉄・ボロン系のような希土類磁石で形成すれば強い磁力を得ることができるので、回転子や電動機全体を小型軽量化することができる。
【００６２】
【発明の効果】
以上のように本発明は、２極の永久磁石回転子において、回転子鉄心の外径を回転子磁極の端部から中心部に向かうにつれて次第に大きくなるような楕円形状に形成した回転子鉄心に、アルミダイカストにより始動用かご形導体を形成した後、永久磁石を装着する製造方法としたものであるので、アルミダイカスト後の回転子鉄心外径が径方向に収縮しても均一な固定子鉄心内径との隙間が確保できて回転子鉄心の外径切削は不要となり、またアルミダイカスト作業も容易で不良品も出にくくなって生産性が上がり、高性能で安価な自己始動形永久磁石式同期電動機を提供することができる。
【図面の簡単な説明】
【図１】参考例１による自己始動形永久磁石式同期電動機の回転子の軸方向断面図
【図２】図１の径方向断面図
【図３】図２のＣ部の部分拡大図
【図４】参考例２による自己始動形永久磁石式同期電動機の回転子の軸方向断面図
【図５】参考例３による自己始動形永久磁石式同期電動機の回転子の電磁鋼板の平面図
【図６】参考例３による自己始動形永久磁石式同期電動機の他の回転子の電磁鋼板の平面図
【図７】本発明の実施例１による自己始動形永久磁石式同期電動機の回転子の電磁鋼板の平面図
【図８】従来の自己始動形永久磁石式同期電動機の径方向断面図
【図９】従来の自己始動形永久磁石式同期電動機の軸方向断面図
【図１０】図８のＡ部の部分拡大図
【符号の説明】
１回転子
２回転子鉄心
３導体バー
４短絡環
５永久磁石
６永久磁石埋設穴
７ブリッジ部Ａ
８空間部
９バリアスロット
１１ブリッジ部Ｂ[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a self-starting permanent magnet synchronous motor used for electric compressors for refrigeration and refrigeration equipment and air-conditioning equipment and general industries..
[0002]
[Prior art]
  The self-starting permanent magnet synchronous motor operates as an induction motor by a squirrel-cage conductor for starting the rotor, and when the rotor reaches near the synchronous speed, the rotor magnetic pole of the permanent magnet creates the synchronous speed created by the rotor winding. The synchronous operation is carried out by being drawn into the rotating magnetic field rotating around, but has excellent performance such as constant speed operation and high efficiency. In particular, various improvements have been made to the rotor structure of an electric motor.
[0003]
  An example of a conventional rotor of a self-starting permanent magnet type synchronous motor is disclosed in Japanese Patent Laid-Open No. 9-308195. Hereinafter, the rotor of the conventional self-starting permanent magnet type synchronous motor will be described with reference to FIGS.
[0004]
  FIG. 8 is a radial sectional view of the rotor, and FIG. 9 is an axial sectional view of the rotor. FIG. 10 is a partially enlarged view of part A in FIG. 8 to 10, reference numeral 1 denotes a rotor, and 2 denotes a rotor core made of laminated electromagnetic steel sheets. Reference numeral 3 denotes a conductor bar, which is formed integrally with a short-circuit ring 4 positioned at both ends of the rotor core 2 and an aluminum die cast to form a starting cage conductor. Reference numeral 5 denotes a permanent magnet. Two permanent magnets 5 having the same polarity are butted in a mountain shape with a bridge portion 7 of the rotor core 2 sandwiched in a permanent magnet embedding hole 6 provided in the axial direction of the rotor core 2. One rotor magnetic pole is formed so as to form a four-pole rotor magnetic pole in the entire rotor.
[0005]
  Two permanent magnets 5 of different polarities adjacent to each other are arranged so as to directly face each other in a mountain shape, and no bridge portion of the rotor core is provided between the permanent magnets 5.
[0006]
  Reference numeral 8 denotes a nonmagnetic end plate for protecting the permanent magnet. 9 is a shaft hole of the rotor 1, and 10 is a shaft attached to the rotor 1.
[0007]
  In addition, in the manufacturing method of the conventional example, after the permanent magnet 5 is inserted into the rotor core 2 and the end plate is brought into contact with the rotor core, the starting cage conductor is formed by aluminum die casting, and the end plate Is also a manufacturing method in which the rotor core 2 is fixed integrally at the same time.
[0008]
[Problems to be solved by the invention]
  However, in the above-described conventional configuration, the bridge portion 7 between the permanent magnets 5 of the same polarity is in contact with the butted end surface of the permanent magnet 5 or is provided with a very small gap as shown in part A of FIG. Absent. As a result, as shown in FIG. 10, the magnetic flux short-circuit between the different poles in the end face 5a of the permanent magnet 5 increases, and the strength of the rotor magnetic pole by the permanent magnet 5 becomes weak. Therefore, the motor has a problem that the step-out torque is reduced, and the current is increased to deteriorate the performance of the motor.
[0009]
  Moreover, the bridge part of the rotor core 2 is not provided between two adjacent permanent magnets 5 of different polarities, and the outer part and the inner part of the permanent magnet embedding hole 6 of the rotor core 2 are bridge parts. There was the fault that it was connected only by 7 and was weak in strength.
[0010]
  Further, after the starting cage conductor is formed of aluminum die casting, when the short ring 4 is cooled and contracts inward, both axial end portions of the rotor core 2 are also subjected to the stress and try to contract inward. At this time, since no bridge portion is provided in the vicinity of the abutting portion between the two permanent magnets 5 having different polarities, the radial width of the permanent magnet embedding hole 6 is reduced and the gap between the permanent magnet 5 inserted before the aluminum die casting is reduced. The outer diameter of the rotor core is reduced.
[0011]
  On the other hand, the radial width of the permanent magnet embedded hole 6 in the vicinity of the bridge portion 7 hardly changes because the bridge portion 7 supports the contraction stress even by aluminum die casting, and the outer diameter of the rotor core 2 does not change. As described above, the outer diameter of the rotor core 2 varies depending on the location. Therefore, the gap between the rotor core 2 and the inner diameter of the stator core 2 can be accurately formed even if the magnetic steel sheet of the rotor core 2 is simply punched out. In other words, there is a problem that it is necessary to perform outer diameter cutting of the rotor core 2 after aluminum die casting, which requires man-hours.
[0012]
  In addition, since the permanent magnet 5 is inserted into the rotor core 2 and the end plate 8 is brought into contact with the rotor core 2 and then the aluminum die casting is performed, the aluminum die casting operation becomes complicated and defective products are likely to be produced. There was a problem.
[0013]
  In view of the above problems, the present invention provides a highly productive manufacturing method that prevents magnetic flux short-circuiting in the rotor core 2, eliminates the need for cutting the outer diameter of the rotor core 2, and facilitates the aluminum die casting operation. An object of the present invention is to provide a self-starting permanent magnet type synchronous motor that is high-performance and inexpensive.
[0014]
[Means for Solving the Problems]
  In order to achieve this object, the present inventionA stator in which a winding is wound around a stator core, a plurality of conductor bars that rotate freely facing an inner cylindrical surface of the stator core, and are located near the outer periphery of the rotor core, and the rotor core A short-circuit ring positioned on both end faces in the axial direction is integrally formed by aluminum die casting to form a squirrel cage conductor, and a rotor having a plurality of permanent magnets embedded inside the conductor bar. In a method for manufacturing a pole self-starting permanent magnet synchronous motor, a bridge portion F having a narrow portion and a wide portion in which a permanent magnet embedding hole for embedding the permanent magnet is provided in a radial direction of the rotor core is sandwiched. In order to form a single rotor magnetic pole by embedding a permanent magnet of the same polarity in this, a magnetic pole short circuit is prevented between the end face of the permanent magnet and the bridge portion F. Provide space for In both cases, two bridge portions G are provided in the radial direction of the rotor core between the permanent magnet embedding holes for embedding adjacent permanent magnets with a magnetic flux short-circuit prevention barrier slot therebetween. A permanent magnet is mounted after a squirrel-cage-shaped conductor is formed by aluminum die casting on a rotor core that is formed in an elliptical shape in which the outer diameter of the iron core gradually increases from the end of the rotor pole toward the center. It is a manufacturing method characterized by this.A permanent magnet of the same polarity is arranged so as to abut in a mountain shape across a radial bridge portion having a narrow portion and a wide portion of the rotor core, and between the end surface of the permanent magnet and the bridge portion. Since the space for preventing magnetic flux short circuit is provided, it is possible to improve the performance of the motor by preventing magnetic flux short circuit between different poles in the end face of the permanent magnet, and the radial direction of the short circuit ring after aluminum die casting The shrinkage distortion at the rotor magnetic pole center of the outer diameter of the rotor core due to the shrinkage of the rotor can be made minute by increasing the strength of the bridge part, so the gap dimension between the stator core inner diameter and the rotor core The electromagnetic steel sheet can be produced with high precision simply by die cutting, and it becomes unnecessary to cut the outer diameter of the rotor core, thereby reducing the number of man-hours.
[0015]
  In addition, since the present invention has a configuration in which permanent magnets of the same polarity are arranged with two bridges provided on the rotor core sandwiched between them, the shrinkage distortion of the outer diameter near the center of the rotor magnetic pole of the rotor core after aluminum die casting Is further reduced, and the gap dimension with respect to the stator core inner diameter can be obtained with higher accuracy.
[0016]
  In addition,Permanent magnet rotorofAfter forming the starting cage conductor with aluminum die casting on the rotor core formed so that the radial gap between the permanent magnet embedding hole and permanent magnet gradually increases from the end of the rotor magnetic pole toward the center Since the manufacturing method is to install a permanent magnet, even if the shrinkage strain in the radial direction of the outer diameter of the rotor core after aluminum die casting increases toward the center of the rotor magnetic pole, the gap between the permanent magnet and the permanent magnet Can be secured sufficiently, and the permanent magnet can be easily inserted into the permanent magnet embedding hole without hindrance. In addition, aluminum die casting is performed without a permanent magnet or end plate, thus simplifying the operation.
[0017]
  in this way,According to the present invention, in a permanent magnet rotor having two poles, the outer diameter of the rotor core is formed in an elliptical shape so as to gradually increase from the end of the rotor magnetic pole toward the center, and the rotor core is made of aluminum die casting. After forming the starting cage conductor, it is a manufacturing method in which a permanent magnet is mounted, so even if the shrinkage strain in the radial direction of the rotor core outer diameter after aluminum die casting increases toward the center of the rotor magnetic pole, Since the outer diameter of the rotor core after contraction can be made substantially circular, the gap dimension with the stator core inner diameter can be accurately obtained simply by punching the electromagnetic steel sheet of the rotor core. The outer diameter cutting of the rotor core is unnecessary and the number of man-hours can be reduced. Moreover, since aluminum die casting is performed without a permanent magnet or end plate, it is easy to work and it is difficult for defective products to be produced, and productivity can be improved.
[0018]
  In the present invention, since the permanent magnet is formed of a rare earth magnet, a strong magnetic force can be obtained, so that the rotor and the entire motor can be reduced in size and weight.
[0019]
  In addition,A stator in which a winding is wound around a stator core, a plurality of conductor bars that rotate freely facing an inner cylindrical surface of the stator core, and are located near the outer periphery of the rotor core, and the rotor core An electric motor comprising a short-circuit ring positioned at both end faces in the axial direction and integrally formed by aluminum die casting to form a squirrel-cage conductor and a rotor in which a plurality of permanent magnets are embedded inside the conductor bar The permanent magnet burying hole is arranged so as to abut on a mountain shape with a bridge portion A having a narrow portion and a wide portion provided in the radial direction of the rotor core, and a permanent magnet of the same polarity. By embedding a magnet, one rotor magnetic pole is formed, and a space portion for preventing magnetic flux short-circuiting is provided between the end face of the permanent magnet and the bridge portion A, and adjacent permanent magnets of different polarities are embedded. Between permanent magnet buried holes Has two bridge parts B in the radial direction of the rotor core with a barrier slot for magnetic flux short-circuit prevention, which prevents the magnetic flux short-circuit in the end face of the permanent magnet and improves the performance of the motor. Later, the shrinkage strain in the radial direction of the outer diameter of the rotor core is very small, and the outer diameter cutting of the rotor core can be performed accurately because the gap dimension with the inner diameter of the stator core can be accurately obtained by simply punching the electromagnetic steel sheet. It has the effect that it becomes unnecessary and the number of man-hours can be reduced.
[0020]
  In addition,A stator in which a winding is wound around a stator core, a plurality of conductor bars that rotate freely facing an inner cylindrical surface of the stator core, and are located near the outer periphery of the rotor core, and the rotor core An electric motor comprising a short-circuit ring positioned at both end faces in the axial direction and integrally formed by aluminum die casting to form a squirrel-cage conductor and a rotor in which a plurality of permanent magnets are embedded inside the conductor bar The permanent magnet embedding hole is arranged so as to abut in a mountain shape with two bridge portions C provided in the radial direction of the rotor core, and a permanent magnet having the same polarity is embedded in the hole. Two rotor magnetic poles are formed, and a space for preventing magnetic flux short-circuiting is provided between the end face of the permanent magnet and the bridge portion C, and between permanent magnet embedding holes for embedding adjacent permanent magnets of different polarities There is a burr to prevent magnetic flux short circuit. By providing two bridge portions B in the radial direction of the rotor core across the slot, the radial shrinkage strain of the rotor core outer diameter at the center of the rotor magnetic pole is further reduced, and the stator core inner diameter is reduced. Therefore, it is possible to further reduce noise and vibration of the electric motor.
[0021]
  In addition,A stator in which a winding is wound around a stator core, a plurality of conductor bars that rotate freely facing an inner cylindrical surface of the stator core, and are located near the outer periphery of the rotor core, and the rotor core A short-circuit ring positioned on both end faces in the axial direction is integrally formed by aluminum die casting to form a squirrel cage conductor, and a rotor having a plurality of permanent magnets embedded inside the conductor bar. In the self-starting permanent magnet type synchronous motor of the pole, in the rotor core formed so that the radial gap between the permanent magnet embedded hole and the permanent magnet gradually increases from the end of the rotor magnetic pole toward the center, This is a manufacturing method in which a permanent magnet is mounted after forming a starting cage conductor by aluminum die casting, and the radial width of the permanent magnet embedding hole is narrowed by aluminum die casting, but the permanent magnet to the rotor core Insertion together can be easily without any trouble, with the effect that aluminum die casting operation is simplified.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
  BookThe invention includes a stator in which a winding is wound around a stator core, a plurality of conductor bars that rotate freely facing an inner cylindrical surface of the stator core, and are positioned near the outer periphery of the rotor core; A short-circuit ring positioned on both end faces in the axial direction of the rotor is integrally formed with aluminum die casting to form a starting cage conductor, and a rotor in which a plurality of permanent magnets are embedded inside the conductor bar. In the two-pole self-starting permanent magnet type synchronous motor, the rotor core is formed in an elliptical shape so that the outer diameter of the rotor core gradually increases from the end of the rotor magnetic pole toward the center. After the starter cage conductor is formed by the manufacturing method, a permanent magnet is mounted, and even if there is shrinkage distortion in the radial direction of the rotor core outer diameter due to aluminum die casting, the gap with the rotor core inner diameter Dimensions are electric Because it can issue only accurately mold punching a steel plate outer diameter cutting rotor core is not required, and has the effect of aluminum die casting operation is able to improve productivity become easy.
[0023]
  In the above,Permanent magnet made of rare earth magnetThenStrong magnetic force is obtained, and the rotor and the entire motor can be reduced in size and weight.
[0024]
【Example】
  Embodiments of a self-starting permanent magnet synchronous motor and a method for manufacturing the same according to the present invention will be described below with reference to the drawings. In additionReference examples will also be described.About the same structure, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted. Since the stator has the same configuration as a general self-starting permanent magnet synchronous motor, description of the stator is also omitted.
[0025]
  (Reference example1)
  This will be described with reference to FIGS. Figure 1Reference example2 is a sectional view in the axial direction of the rotor of the self-starting permanent magnet synchronous motor 1 according to FIG. 2, and FIG. 2 is a sectional view in the radial direction of FIG. FIG. 3 is a partially enlarged view of a portion M in FIG.
[0026]
  In FIG. 1 to FIG. 3, 1 is a rotor, and 2 is a rotor core made of laminated electromagnetic steel sheets. Reference numeral 3 denotes a conductor bar, which is integrally formed with a short-circuit ring 4 positioned at both ends in the axial direction of the rotor core 2 and an aluminum die cast to form a starting cage conductor. Reference numeral 5 denotes a permanent magnet, and two flat permanent magnets 5 having the same polarity are sandwiched between permanent magnet embedded holes 6 provided in the axial direction of the rotor core 2 with the bridge portion A7 of the rotor core 2 interposed therebetween. One rotor magnetic pole is formed so as to match the shape, and the rotor as a whole forms two rotor magnetic poles.
[0027]
  Here, the bridge portion A of 7 is designed to have a narrow portion 7a and a portion 7b that becomes wider from the outer diameter side toward the outer diameter side. Magnetic flux short circuit between the opposite poles of the permanent magnet 5 is prevented by magnetic saturation of the narrow portion 7a.
[0028]
  Moreover, since the space part 8 is provided between the end surface 5a of the permanent magnet 5 and the bridge part A7, the magnetic flux short circuit between the different poles in the end surface 5a of the permanent magnet 5 can be prevented.
[0029]
  Reference numeral 9 denotes a barrier slot for preventing a magnetic flux short circuit provided between adjacent permanent magnets 5 of different polarities, in which aluminum 10 is filled with aluminum die casting. The bridge portion B11 of the rotor core 2 between the barrier slot 9 and the permanent magnet embedding hole 6 is set to have a narrow width, and this portion is magnetically saturated to prevent a magnetic flux short circuit between the permanent magnets 5 of different polarities. In addition, a space 12 is provided between the end face of the permanent magnet 5 and the bridge part B11 to prevent a magnetic flux short circuit between different poles in the end face of the permanent magnet 5. Reference numeral 13 denotes a nonmagnetic end plate for protecting the permanent magnet 5, and is fixed to both end faces of the rotor core 2 by rivet pins 14. Reference numeral 15 denotes a rotor shaft hole.
[0030]
  The rotor 1 having the above configuration is manufactured by forming a starting cage conductor by aluminum die casting on a rotor core 2 formed by laminating electromagnetic steel plates, and then embedding the permanent magnet 5 in the permanent magnet embedding hole 6. The order in which the end plate 13 is fixed to both end faces of the rotor core 2 with the rivet pins 14 is taken.
[0031]
  Here, after aluminum die casting is performed, when the aluminum is cooled, the short-circuiting ring contracts in the radial direction, and accordingly, the rotor core 2 is also subjected to contraction stress in the inner diameter direction. However, as shown in FIG. 2, since the bridge portion B11 of the rotor core 2 is provided at two locations around the barrier slot 9 in the vicinity of the barrier slot 9, the strength against contraction stress is strong, so the outer diameter of the rotor core 2 is small. The shrinkage strain in the radial direction is small.
[0032]
  On the other hand, since there is only one bridge portion A7, the distortion in the inner diameter direction of the rotor core 2 at this portion increases. In order to prevent this, by shortening the radial length of the narrow portion 7a that prevents magnetic flux short-circuiting due to magnetic saturation of the bridge portion A7, and by providing the subsequent wide portion 7b, the entire bridge portion A7 is The strength against the shrinkage stress in the radial direction is increased to prevent distortion in the inner diameter direction of the rotor core 2 near the bridge portion A7.
[0033]
  As a result, the outer diameter of the rotor core 2 can be ensured to be a shape close to a perfect circle. Therefore, when the electromagnetic steel sheet of the rotor core 2 is punched into a die, the outer diameter of the rotor core 2 is a gap with the inner diameter of the rotor core in advance. If a predetermined dimension can be obtained, the step of cutting the outer diameter of the rotor core after aluminum die casting to obtain a predetermined gap dimension can be omitted.
[0034]
  In additionReference exampleIn the above description, the example of the rotor having two poles has been described. However, the present invention is not limited to this, and the rotor may have another number of rotor poles such as four poles.
[0035]
  In addition, although the permanent magnet has been described as having a flat plate shape, it may have another shape such as an arc shape.
[0036]
  As aboveReference exampleAccording to No. 1, it is possible to prevent a magnetic flux short circuit between permanent magnets to ensure high performance, and to provide a high-performance and inexpensive self-starting permanent magnet synchronous motor that eliminates the need for cutting the outer diameter of the rotor core. it can.
[0037]
  (Reference example2)
  This will be described with reference to FIG. Figure 4Reference example2 is a radial sectional view of a rotor of a self-starting permanent magnet type synchronous motor according to FIG.
[0038]
  In FIG. 4, reference numeral 21 denotes a bridge portion C of the rotor core 2, and two flat permanent magnets 5 having the same polarity are arranged so as to abut on a mountain shape with two bridge portions C <b> 21 interposed therebetween. Two rotor magnetic poles are formed, and the rotor as a whole forms two rotor magnetic poles. Reference numeral 22 denotes a space between two bridge portions C21, which is designed to narrow the width of the bridge portion C21 to prevent magnetic flux short-circuit between the opposite poles of the permanent magnet 5.
[0039]
  Reference numeral 23 denotes a space provided between the end face of the permanent magnet 5 and the bridge C21.Reference exampleAs in the case of 1, the magnetic flux short-circuit between the different poles in the end face of the permanent magnet 5 is prevented.
[0040]
  With the above configuration, the shrinkage strain in the radial direction in the vicinity of the bridge portion C21 of the rotor core 2 due to the shrinkage in the radial direction of the short-circuit ring after aluminum die casting is described above because two bridge portions C are provided.Reference exampleAs compared with the case of one bridge portion of 1, the strength is so strong that it hardly occurs, and the outer diameter of the rotor core 2 after aluminum die casting is further improved in roundness so that the gap dimension with the inner diameter of the rotor core is increased. The electric motor can be made uniform, and the motor can be further reduced in noise and vibration.
[0041]
  (Reference example3)
  This will be described with reference to FIGS.
[0042]
  FIG.Reference example3 is a plan view of a magnetic steel sheet of a rotor of a self-starting permanent magnet type synchronous motor according to FIG. Fig. 6Reference example3 is a plan view of an electromagnetic steel plate of another rotor in FIG.
[0043]
  In FIG. 5, 31 is a magnetic steel sheet, and a predetermined number of sheets are laminated to form a rotor core, and then a starting cage conductor is formed on the rotor core by aluminum die casting. Reference numeral 32 denotes a conductor bar slot filled with a conductor bar of a starting cage conductor, and 33 denotes a permanent magnet embedding hole.
[0044]
  Two permanent magnets of the same polarity are embedded in the two permanent magnets 33 after aluminum die casting as shown by a two-dot chain line to form one rotor magnetic pole. Further, permanent magnets of different polarities are embedded in the two lower permanent magnet embedding holes 33, and the rotor as a whole constitutes a two-pole rotor magnetic pole. Reference numeral 34 denotes a bridge portion D, which is narrowed to cause magnetic saturation to prevent a magnetic short circuit between the opposite surfaces of the permanent magnet. Reference numeral 35 denotes a barrier slot for preventing a magnetic flux short circuit. The barrier slot 35 is interposed between the upper and lower adjacent permanent magnet embedding holes 33 and the width of the two bridge portions E36 formed between the permanent magnet embedding holes 33 is narrow. By setting, this portion is magnetically saturated to prevent a magnetic flux short circuit between adjacent permanent magnets of different polarities. 37 is a hole for passing a rivet pin for fixing the end plate, and 38 is a shaft hole.
[0045]
  Here, the radial hole width of the permanent magnet embedding hole 33 is the gap P between the permanent magnet embedding hole 33 and the permanent magnet indicated by a two-dot chain line at the end of the rotor magnetic pole (that is, near the barrier slot 36).₁, And the gap is gradually increased toward the center of the rotor magnetic pole (ie, near the bridge portion D34).₂(P₂> P₁)
Set to.
[0046]
  In the drawings, the gaps are exaggerated and drawn for easy understanding.
[0047]
  The rotor steel core is formed by punching the magnetic steel sheets having the above shapes with a metal mold to form a rotor core. After forming a starting cage conductor by aluminum die casting, a permanent magnet is mounted. After the rotor is die-casted, the short-circuit rings (not shown) formed at both ends in the axial direction of the rotor core of the starting cage conductor cool down and shrink in the radial direction. Under the contraction stress of the short-circuit ring, it contracts in the radial direction. At that time, the permanent magnet buried hole 33 has a strong strength because there are two bridge portions E36 at the end of the rotor magnetic pole, and the hole width hardly changes. However, the permanent magnet embedded hole 33 contracts because there is only one bridge portion 35 at the magnetic pole center. The strength is weak against stress, and the hole width of the permanent magnet is narrowed. However, since the magnetic steel sheet has a shape with a large gap with the permanent magnet at the center of the magnetic pole of the permanent magnet embedded hole 33, the hole width at this point becomes too narrow and the permanent magnet cannot be inserted. The rotor can be assembled smoothly.
[0048]
  In FIG. 6, one rotor magnetic pole is formed by two plate-shaped permanent magnets having the same polarity. However, one or more plate-shaped permanent magnets may be used to form one rotor magnetic pole. The shape of the permanent magnet may be other shapes such as an arc shape.
[0049]
  In addition, FIG. 6 shows that one rotor magnetic pole is formed by only one arc-shaped permanent magnet as shown by a two-dot chain line, and a two-pole rotor magnetic pole is formed by two arc-shaped permanent magnets in the entire rotor. It is an electromagnetic steel sheet of a rotor core that does. Although the explanation of the individual symbols is omitted, the gap Q between the permanent magnet embedding hole 43 and the permanent magnet at the end of the rotor magnetic pole is the same as described in FIG.₁At the center of the rotor magnetic pole, the gap Q₂(Q₂> Q₁) Is set widely, the same effect as the example of FIG. 5 can be obtained.
[0050]
  AlsoIn reference exampleThe aluminum die casting is performed without attaching a permanent magnet or an end plate, so that the work is easy and it is difficult to produce defective products, so that productivity can be improved.
[0051]
  (Example1)
  This will be described with reference to FIG.
[0052]
  FIG. 7 shows an embodiment of the present invention.1It is a top view of the electromagnetic steel plate of the rotor of the self-starting type permanent magnet type synchronous motor.
[0053]
  In FIG. 7, reference numeral 51 denotes an electromagnetic steel sheet. After a predetermined number of sheets are laminated to form a rotor core, a starting cage conductor is formed on the rotor core by aluminum die casting. 52 is a slot for a conductor bar, 53 is a permanent magnet embedding hole, 54 is a bridge portion F, 55 is a barrier slot for preventing a magnetic flux short circuit, and 56 is a bridge portion G. Reference numeral 57 denotes a hole through which a rivet for fixing the end plate is passed, and 58 is a shaft hole. Each part is described aboveReference exampleThe same role as in the case of 3 is assumed, and the description is omitted to avoid duplication. Further, a two-dot chain line indicates a permanent magnet to be inserted after aluminum die casting, and the rotor forms a two-pole rotor magnetic pole.
[0054]
  Here, the outer diameter of the electromagnetic steel sheet 51 is such that the end of the rotor magnetic pole has a predetermined gap dimension between the inner diameter of the stator core and the stator core inner diameter.₁The outer diameter is increased toward the center of the rotor magnetic pole, and the outer diameter of the center of the rotor magnetic pole is R₂(R₂> R₁). The magnetic steel sheet having the above shape is punched and a predetermined number of layers are laminated to form a rotor core, and a starting cage conductor is formed thereon by aluminum die casting, and then a permanent magnet is mounted.
[0055]
  After aluminum die casting, the short-circuit rings (not shown) formed on both axial end faces of the rotor core of the starting cage conductor cool down and shrink in the radial direction. In response to the shrinkage stress, it shrinks in the radial direction.
[0056]
  At this time, since the rotor magnetic pole end of the electromagnetic steel plate 51 of the rotor core has two bridge portions G56, the strength against the contraction stress in the inner diameter direction is strong, so the outer diameter R of the rotor core.₁Hardly changes. However, since there is only one bridge portion F54 at the center of the rotor magnetic pole, the strength is weak and the outer diameter R of the rotor core is small.₂Receives shrinkage stress and shrinks in the radial direction. At this time, outer diameter R₂The dimension after shrinkage is R₁Is set so that the entire outer diameter of the rotor core is R.₁The shape can be almost a perfect circle.
[0057]
  In FIG. 7, the outer diameter R after shrinkage₁The circle of is shown with a two-dot chain line, but R₁And R₂The dimensional differences are exaggerated and drawn for easy understanding.
[0058]
  In FIG. 7, one rotor magnetic pole is formed by two flat permanent magnets having the same polarity, but one rotor magnetic pole is formed by one arc-shaped permanent magnet as shown in FIG. You may let them.
[0059]
  As described above, according to the present invention, since the outer diameter of the rotor core after aluminum die casting is almost perfect circle, the gap with the inner diameter of the stator core can be formed by punching in advance with a punching die. It is not necessary to cut out the outer diameter of the iron core and dimension it, and man-hours can be reduced.
[0060]
  In addition, since aluminum die casting is performed in a state where no permanent magnets or end plates are mounted, it is easy to work and it is difficult for defective products to be produced. Together, both can improve productivity.
[0061]
  (Reference example 4)
  Although not shown, since a strong magnetic force can be obtained if the permanent magnet is formed of a rare earth magnet such as neodymium, iron, or boron, the rotor and the entire motor can be reduced in size and weight.
[0062]
【The invention's effect】
  As aboveBookThe invention starts with an aluminum die casting in a rotor core formed in an elliptical shape in which the outer diameter of the rotor core gradually increases from the end of the rotor magnetic pole toward the center in a two-pole permanent magnet rotor After forming the cage-shaped conductor, the manufacturing method is to attach a permanent magnet. Therefore, even if the outer diameter of the rotor core after aluminum die casting shrinks in the radial direction, there is a uniform gap with the inner diameter of the stator core. To provide a high-performance and inexpensive self-starting permanent-magnet synchronous motor that can be secured, eliminates the need for cutting the outer diameter of the rotor core, and makes it easy to die-cast aluminum, making it difficult to produce defective products. Can do.
[Brief description of the drawings]
[Figure 1]referenceAxial sectional view of rotor of self-starting permanent magnet synchronous motor according to example 1
FIG. 2 is a radial sectional view of FIG.
FIG. 3 is an enlarged view of part C of FIG.
[Fig. 4]referenceAxial sectional view of rotor of self-starting permanent magnet synchronous motor according to example 2
[Figure 5]referencePlan view of electromagnetic steel plate of rotor of self-starting permanent magnet type synchronous motor according to example 3
[Fig. 6]referencePlan view of electromagnetic steel plate of other rotor of self-starting permanent magnet type synchronous motor according to example 3
FIG. 7 shows an embodiment of the present invention.1Plan of Magnetic Steel Sheet of Rotor of Self-Starting Permanent Magnet Synchronous Motor
FIG. 8 is a radial sectional view of a conventional self-starting permanent magnet type synchronous motor.
FIG. 9 is an axial sectional view of a conventional self-starting permanent magnet type synchronous motor.
10 is a partially enlarged view of part A in FIG. 8;
[Explanation of symbols]
  1 Rotor
  2 Rotor core
  3 Conductor bar
  4 Shorting ring
  5 Permanent magnet
  6 Permanent magnet hole
  7 Bridge part A
  8 Space
  9 Barrier slot
  11 Bridge part B

Claims

A stator in which a winding is wound around a stator core, a plurality of conductor bars that rotate freely facing an inner cylindrical surface of the stator core, and are located near the outer periphery of the rotor core, and the rotor core A short-circuit ring positioned on both end faces in the axial direction is integrally formed by aluminum die casting to form a squirrel cage conductor, and a rotor having a plurality of permanent magnets embedded inside the conductor bar. In the method for manufacturing a pole self-starting permanent magnet synchronous motor , a bridge portion (F) having a narrow portion and a wide portion in which a permanent magnet embedding hole for embedding the permanent magnet is provided in a radial direction of the rotor core Is arranged so as to abut against the mountain shape, and a permanent magnet of the same polarity is embedded in this to form one rotor magnetic pole, and between the end face of the permanent magnet and the bridge portion (F) Space for preventing magnetic flux short circuit And providing two bridge portions (G) in the radial direction of the rotor core with a barrier slot for preventing magnetic flux short-circuiting between permanent magnet embedding holes for embedding adjacent permanent magnets of different polarities, the outer diameter of the rotor core in the rotor core formed gradually larger such elliptical shape toward the center from the end of the rotor magnetic poles, after forming the starting cage conductor by aluminum die casting, permanent magnets A method of manufacturing a self-starting permanent magnet type synchronous motor , characterized by comprising: