JP3829572B2

JP3829572B2 - Transformer and manufacturing method thereof

Info

Publication number: JP3829572B2
Application number: JP2000054568A
Authority: JP
Inventors: 浩康北村; 秀明安倍; 直有村
Original assignee: Matsushita Electric Works Ltd
Current assignee: Panasonic Electric Works Co Ltd
Priority date: 1999-12-15
Filing date: 2000-02-29
Publication date: 2006-10-04
Anticipated expiration: 2020-02-29
Also published as: JP2001237126A

Description

【０００１】
【発明の属する技術分野】
本発明は、プッシュプル型の電源回路に用いるトランスに関するものである。
【０００２】
【従来の技術】
一般に、プッシュプル型（センタタップ型ともいう）のスイッチング電源回路には、図１７に示すように、１次巻線ｎ１と２次巻線ｎ２とにそれぞれセンタタップを備えるトランスＴが用いられる。この電源回路は、制御回路ＣＮ１，ＣＮ２により高周波（一般には数十ｋＨｚ）で交互にオンオフされる２個のスイッチング素子Ｑ１，Ｑ２を備える。両スイッチング素子Ｑ１，Ｑ２は一端が共通に接続され（図示例ではスイッチング素子Ｑ１，Ｑ２としてＭＯＳＦＥＴを用いており、ソースが共通に接続されている）、各他端がそれぞれトランスＴの１次巻線ｎ１の各一端に接続されている。１次巻線ｎ１のセンタタップは直流電源ＤＣの一方の出力端（図示例では正極）に接続され、スイッチング素子Ｑ１，Ｑ２の上記一端は直流電源ＤＣの他方の出力端（図示例では負極）に接続される。トランスＴの１次巻線の各一端とセンタタップとの間にはそれぞれコンデンサＣ１，Ｃ２が接続される。コンデンサＣ１，Ｃ２はトランスＴの漏れインダクタンスとともに共振回路を構成し、スイッチング素子Ｑ１，Ｑ２のゼロボルトスイッチングを可能にする。
【０００３】
また、トランスＴの２次巻線ｎ２の両端にはそれぞれダイオードＤ１，Ｄ２のアノードが接続される。ダイオードＤ１，Ｄ２のカソードは共通に接続され、トランスＴの２次巻線ｎ２のセンタタップとの間で脈流電圧を出力する。つまり、トランスＴの２次巻線ｎ２とダイオードＤ１，Ｄ２とにより全波整流回路が構成されている。全波整流回路の出力はインダクタＬとコンデンサＣとからなるチョークインプット型のフィルタ回路を通して負荷Ｚに供給される。
【０００４】
しかして、スイッチング素子Ｑ１，Ｑ２が交互にオンオフされると、１次巻線ｎ１の各一端とセンタタップとの間で交互に電流が流れ、２次巻線ｎ２には１次巻線ｎ１に流れる電流の向きに応じて交番する電圧が発生する。つまり、１次巻線ｎ１においてセンタタップと各一端との間の２つの巻線ｎ１１，ｎ１２には、つねに一方にのみ電流が流れ、電流が同時に流れることはない。このように直流−交流変換が行われ、トランスＴの２次巻線ｎ２に発生した交番電圧は整流されフィルタ回路を通ることによって直流電圧に変換されるから、図示例の回路では直流−直流変換が行われる。
【０００５】
ところで、上述のように漏れインダクタンスを共振用のインダクタンスとして利用するために、１次巻線ｎ１と２次巻線ｎ２とを完全に結合させず分割巻きにしてあり、１次巻線ｎ１と２次巻線ｎ２との間の磁路を形成するコア３にはエアギャップが形成される。上述したように、１次巻線ｎ１と２次巻線ｎ２とはそれぞれセンタタップを有しているから、１次巻線ｎ１と２次巻線ｎ２とはそれぞれセンタタップと各一端との間の２個ずつの巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を備えており、１次巻線ｎ１と２次巻線ｎ２とを分割巻きにするために、これらの巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を図１８に示す位置関係にすることが考えられている（特開昭６３−２１１７１１号公報）。
【０００６】
すなわち、図１８（ａ）に示すものは、コイルボビン１の長手方向の両端部に鍔部２ａ，２ｂを設けるとともに、長手方向の中間部に１個の分割鍔２ｃを形成し、鍔部２ａと分割鍔２ｃとの間に１次巻線ｎ１を形成する２個の巻線ｎ１１，ｎ１２を順に重ねて巻装し、鍔部２ｂと分割鍔２ｃとの間に２次巻線ｎ２を形成する２個の巻線ｎ２１，ｎ２２を順に重ねて巻装している。また、図１８（ｂ）に示すものは、コイルボビン１の長手方向の中間部に２個の分割鍔２ｄ，２ｅを形成し、鍔部２ａと分割鍔２ｄとの間に１次巻線ｎ１の一方の巻線ｎ１１を巻装し、鍔部２ｂと分割鍔２ｅとの間に１次巻線ｎ１の他方の巻線ｎ１２を巻装し、さらに両分割鍔２ｄ，２ｅの間に２次巻線ｎ２の各巻線ｎ２１，ｎ２２を順に重ねて巻装してある。図１８（ｃ）に示すものは、コイルボビン１の長手方向の中間部に３個の分割鍔２ｆ〜２ｈを形成し、分割された各部位にそれぞれ巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を巻装してある。
【０００７】
【発明が解決しようとする課題】
ところで、上述したトランスＴは、巻線に流れた電流と巻線の抵抗とから算出される損失以上の損失が生じる。この損失の１つの原因は漏れインダクタンスを共振用のインダクタンスとして利用するために１次巻線ｎ１と２次巻線ｎ２とを完全に結合させていないことであるが、他の原因としては巻線に高周波電流が流れることによる近接効果の影響が大きいと考えられる。すなわち、トランスＴでの損失を低減するには近接効果の影響を低減することが要求される。
【０００８】
本発明は上記事由に鑑みて為されたものであり、その目的は、損失を低減したトランスを提供することにある。
【０００９】
【課題を解決するための手段】
請求項１の発明は、コアの異なる部位に巻装された１次巻線と２次巻線との少なくとも一方がセンタタップと各一端との間の２つの巻線からなるトランスであって、前記センタタップと各一端との間の２つの巻線が夫々並列接続された複数本の線路からなり、各線路が１つの層となるとともに、センタタップと各一端との間の各巻線の層が交互に重なるようにコイルボビンに巻装されているものである。
【００１０】
請求項２の発明は、請求項１の発明において、前記１次巻線のみにおいてセンタタップと各一端との間の２つの巻線の層が交互に重なるようにコイルボビンに巻装されているものである。
【００１１】
請求項３の発明は、請求項１の発明において、前記１次巻線と前記２次巻線との両方がセンタタップを有し、それぞれのセンタタップと各一端との間の２つの巻線の層が交互に重なるようにコイルボビンに巻装されているものである。
【００１２】
請求項４の発明は、請求項２の発明において、前記１次巻線と前記２次巻線との両方がセンタタップを有し、２次巻線における２つの巻線が１次巻線を両側から挟む形で配置されているものである。
【００１３】
請求項５の発明は、請求項１ないし請求項４の発明において、前記コアは２つのＥ型コアを組み合わせた日字状に形成されているものである。
【００１４】
請求項６の発明は、請求項１ないし請求項３の発明において、前記１次巻線を磁路の一部が開放された第１のコアに巻装した第１のトランス半体と、前記２次巻線を磁路の一部が開放された第２のコアに巻装した第２のトランス半体とを備え、第１および第２のコアにおいて磁路の開放されている部位同士を突き合わせる形で第１および第２のトランス半体を分離可能に対向配置するものである。
【００１５】
請求項７の発明は、請求項１ないし請求項６の発明において、少なくとも１つの層は撚り線を巻装して形成されているものである。
【００１６】
請求項８の発明は、請求項１ないし請求項７の発明において、前記コイルボビンにおいて各巻線を巻装する領域がそれぞれ仕切られ、各巻線を巻装する領域を埋めて隙間を形成しないようにセンタタップと各一端との間の２つの巻線の層が巻装されているものである。
【００１７】
請求項９の発明は、請求項１の発明において、上記センタタップと各一端との間の２つの巻線はそのセンタタップ側の各端部がコイルボビンの一方側に、センタタップ側でない端部をコイルボビンの他方側に位置して２つの巻線のセンタタップ側の端部がセンタタップに接続されているものである。
【００１８】
請求項１０の発明は、請求項９の発明において、センタタップと各一端との間の２つの巻線のコイルボビンに対する巻き始め位置が同じとなっているものである。
【００１９】
請求項１１の発明は、請求項９または請求項１０の発明において、次巻線用のコイルボビンと２次巻線用のコイルボビンとが独立しているとともに、これらコイルボビンは外部接続用ピンを備えた台座に連結されて上記ピンに巻線が接続されているものである。
【００２０】
請求項１２の発明は、コアの異なる部位に巻装された１次巻線と２次巻線との少なくとも一方がセンタタップと各一端との間の２つの巻線からなるとともに、センタタップと各一端との間の上記２つの巻線が、並列接続された複数本の線路からなるトランスの製造方法であって、センタタップと各一端との間の上記２つの巻線である第１の巻線と第２の巻線のうちの第１の巻線の第１の線路をコイルボビンに巻き、ついで第１の巻線の第１の線路の外周に第２の巻線の第１の線路を逆巻きで巻き、この後、第２の巻線の第１の線路の外周に第１の巻線の第２の線路を巻き、さらに第１の巻線の第２の線路の外周に第２の巻線の第２の線路を巻いて、上記４つの線路のコイルボビンの一方側に位置する各端部をセンタタップに接続し、コイルボビンの他方側に位置する第１の巻線の２つの線路の各端部と第２の巻線の２つの線路の各端部とを夫々相互に接続するものである。
【００２１】
請求項１３の発明は、請求項１２の発明において、巻線の各端部はコイルボビンに設けたプリント板取付用のピンに接続するものである。
【００２２】
請求項１４の発明は、センタタップと各一端との間の２つの巻線の各線路をコイルボビンに対して同一位置から巻き始めるものである。
【００２３】
【発明の実施の形態】
以下の実施形態では、図８に示したスイッチング電源回路に用いるトランスＴを示す。
【００２４】
（第１の実施の形態）
本実施形態は基本的には、図１に示すように、コイルボビン１の長手方向において、１次巻線ｎ１を巻装する領域と２次巻線ｎ２を巻装する領域とを形成し、１次巻線ｎ１を形成する２個の巻線ｎ１１，ｎ１２と２次巻線ｎ２を形成する２個の巻線ｎ２１，ｎ２２とをそれぞれいわゆるサンドイッチ巻きとしてある。サンドイッチ巻きとは、２つの巻線を多層巻きとする場合に、１層ずつ異なる巻線を交互に巻装する巻き方である。また、コア３には２個のＥ型コア３ａ，３ｂを組み合わせた日字状のＥＥ型コアを用いており、Ｅ型コア３ａ，３ｂの中央片をコイルボビン１に挿通して１次巻線ｎ１と２次巻線ｎ２との中心に通し、Ｅ型コア３ａ，３ｂの残りの部分で１次巻線ｎ１と２次巻線ｎ２とを囲むようにして磁路を形成してある。ここに、漏れ磁束を得るために、Ｅ型コア３ａ，３ｂの突き合わせ部分にはエアギャップが形成される。
【００２５】
さらに具体的に説明すると、図２に示すように、コイルボビン１は長手方向の両端部に鍔部２ａ，２ｂが形成されるとともに中間部に分割鍔２ｃが形成されることによって、１次巻線ｎ１を巻装する領域と２次巻線ｎ２を巻装する領域とに分割されており、鍔部２ａと分割鍔２ｃとの間には１次巻線ｎ１を形成する２個の巻線ｎ１１，ｎ１２が１層ずつ交互に巻装される。ここに、一方の巻線ｎ１１を密着巻きで１層分巻装した後には巻線ｎ１１の外周に絶縁テープ４が巻かれ、絶縁テープ４の外側に他方の巻線ｎ１２が１層分巻装される。さらに、巻線ｎ１２の外側に絶縁テープ４が巻かれ、絶縁テープ４の外側に上記一方の巻線ｎ１１が巻装される。同様の手順で２つの巻線ｎ１１，ｎ１２が順に１層ずつ交互に巻装されるのである。図示例では巻線ｎ１１，ｎ１２を４層に巻装してあり、各層はそれぞれ図３のように巻装されるとともに、図３において同符号を付した各層の端点が互いに接続される。つまり、同じ巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を形成する各層同士は互いに並列接続され、異なる巻線ｎ１１，ｎ１２、ｎ２１ｎ２２のうちセンタタップとなる端点は互いに接続される。つまり、図示例では１次巻線ｎ１および２次巻線ｎ２をそれぞれ並列接続された複数の線路に分割し、各線路を１つの層とする形で異なる巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を交互に重ねて巻装するのである。こうして端点ロがセンタタップになり、端点イが巻線ｎ１１の一端、端点ハが巻線ｎ１２の一端になる。２次巻線ｎ２についても同様に巻装される。
【００２６】
したがって、たとえば巻線ｎ１１の断面積をＳとし、第１層と第３層として巻装する巻線に直径の等しいものを用いるとすれば、１層当たりの巻線の断面積はＳ／２になる。他の巻線ｎ１２、ｎ２１，ｎ２２も同様である。
【００２７】
上述したプッシュプル型のスイッチング電源回路では、１次巻線ｎ１の各巻線ｎ１１，ｎ１２に同時に電流が流れることがないから、２つの巻線ｎ１１，ｎ１２の相互作用はほとんどない。しかも各巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を形成する層間には他方の巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を形成する層が存在するから（たとえば、巻線ｎ１１の層の間に巻線ｎ１２の層が存在する）、１つの巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２の層間における近接作用の影響が軽減される。つまり、１つの巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を並列接続された複数の線路に分割して各線路でそれぞれ層を形成するとともに、層間に他の巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２の層を介在させることによって、近接効果の影響を軽減することができる。一方、１次巻線ｎ１と２次巻線ｎ２とはコイルボビン１において分割鍔２ｃにより分割された異なる領域にそれぞれ巻装され、コアにエアギャップが形成されているから完全には結合しておらず漏れインダクタを利用することができる。
【００２８】
上述した構成例では、１つの巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を２つの線路に分割しているが、３つ以上の線路に分割してもよい。また、分割するに際して各線路の断面積は必ずしも均等でなくてもよい。たとえば、全体の断面積をＳとするとき２分割にあたって、一方の断面積をＳ／３とし、他方の断面積を２Ｓ／３などとしてもよい。
【００２９】
（第２の実施の形態）
本実施形態は、図４（ａ）に示すように、各巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２を分割した線路をさらに２本の素線によって形成し、両素線をコイルボビン１に同時に巻装したものである（要するに、両巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２をバイファイラ巻きにしてある）。これは１層当たりの巻数が少ないなどの理由によって、図４（ｂ）のようにコイルボビン１において１次巻線ｎ１または２次巻線ｎ２を巻装する領域に巻線の巻装されない部分が生じるようなときに有効であって、複数の線路を１層に同時に巻装することで巻線を巻装する領域の両端間が埋まるようにする。
【００３０】
本実施形態の構成は通常の単線を用いる代わりに細径の線を撚ったリッツ線を用いることでも実現できる。しかもリッツ線のような撚り線を用いると表皮効果の影響を低減することができる。また、巻線には一般の銅線のような断面円形の材料ではなく、銅箔のような断面矩形状などの材料を用いることも可能である。他の構成および動作は第１の実施の形態と同様である。
【００３１】
上述した構成例では、コア３をＥ型コア３ａの組み合わせとしているが、図５に示すように、全体としてロ字型をなすように２個のＵ型コア３ｃ，３ｄの組み合わせとするなど他の形式のコア３を用いてもよい。この場合は、各Ｕ型コア３ｃ，３ｄの一方の脚片の突き合わせ部分付近に１次巻線ｎ１を巻装し、他方の脚片の突き合わせ部分に２次巻線ｎ２を巻装する。
【００３２】
（第３の実施の形態）
本実施形態は、図６に示すように、１次巻線ｎ１と２次巻線ｎ２とを各別のハウジング５ａ，５ｂに収納したものである。すなわち、第１の実施の形態において用いたコイルボビン１を分離鍔２ｃの部位で２分割した形状のコイルボビン１ａ，１ｂを用い、一方のコイルボビン１ａに１次巻線ｎ１の巻線ｎ１１，ｎ１２を巻装し、他方のコイルボビン１ｂに２次巻線ｎ２の巻線ｎ２１，ｎ２２を巻装している。１次巻線ｎ１と２次巻線ｎ２との巻装の仕方は第１の実施の形態と同様であって、各巻線ｎ１１，ｎ１２、ｎ２１，ｎ２２をそれぞれ並列接続された複数の線路に分割し、各線路ごとに層を形成するとともに１つの巻線の層間に他の巻線の層を介在させるようにして多層巻きとする。また、コア３には２個のＥ型コア３ａを用いており、各Ｅ型コア３ａを各ハウジング５ａ，５ｂにそれぞれ配置してある。つまり、各ハウジング５ａ，５ｂにそれぞれトランスＴの半分ずつを構成するトランス半体Ｔ１，Ｔ２が収納される。
【００３３】
１次巻線ｎ１を巻装したトランス半体Ｔ１を収納するハウジング５ａには凹所６が形成され、トランス半体Ｔ１におけるＥ形コア３ａの中央片および両側片の先端面が凹所６の底面に望むように配置される。また、ハウジング５ｂには２次巻線ｎ２を巻装したトランス半体Ｔ２が収納され、トランス半体Ｔ２の中央片および両側片の先端面をトランス半体Ｔ１の中央片および両側片に位置合わせしたときに、ハウジング５ｂの一部がハウジング５ａに設けた凹所６に嵌合するようにしてある。各Ｅ型コア３ａ，３ｂの先端面において磁路は開放されており、ハウジング５ｂをハウジング５ａの凹所６に嵌合させると、各Ｅ型コア３ａ，３ｂにおいて磁路の開放されている部位同士が突き合わせられる形で両トランス半体Ｔ１，Ｔ２が対向配置される。したがって、両トランス半体Ｔ１，Ｔ２がトランス結合されることで、１次巻線ｎ１から２次巻線ｎ２への電力の伝達が可能になる。
【００３４】
上述の構成によれば、各トランス半体Ｔ１，Ｔ２をハウジング５ａ，５ｂの外部に露出させることなく、両ハウジング５ａ，５ｂ間での電力の伝達が可能になるから、ハウジング５ａ，５ｂを密封しながらもハウジング５ａからハウジング５ｂへの電力供給が可能になり、浴室や屋外のような防水性や防塵性が要求される環境での電力の供給に適したものになる。他の構成および動作は第１の実施の形態と同様である。
【００３５】
（第４の実施の形態）
本実施形態は、漏れインダクタンスを小さくするものであり、図７に示すように、コイルボビン１として図１８（ｂ）に示したものと同様に、長手方向の両端に鍔部２ａ，２ｂを備えるとともに、長手方向の中間部に２つの分離鍔２ｄ，２ｅを形成することによって、巻線を巻装する領域を３つ設けたものを用いる。中央の領域には１次巻線ｎ１の各巻線ｎ１１，ｎ１２を交互に層にして多層巻きに巻装し、両側の領域にはそれぞれ２次巻線ｎ２の各巻線ｎ２１，ｎ２２をそれぞれ巻装してある。この構成では、１次巻線ｎ１の両側に２次巻線ｎ２を配置していることによって、１次巻線ｎ１で生じる磁束の大部分が２次巻線ｎ２を通ることになり、第１の実施の形態の構成に比較すると漏れ磁束は低減する。他の構成および動作は第１の実施の形態と同様である。
【００３６】
（第５の実施の形態）
図８に示す実施形態は、第１の実施形態のものにおける巻線ｎ１１，ｎ１２の巻き付けについて詳しく示したものであり、一方の巻線ｎ１１の一方の線路を密着巻きで１層分巻装した後に巻線ｎ１１の外周に絶縁テープ４を巻き、絶縁テープ４の外側に他方の巻線ｎ１２の一方の線路を逆巻きで巻装する。さらに、巻線ｎ１２の外側に絶縁テープ４を巻き、絶縁テープ４の外側に上記一方の巻線ｎ１１の他方の線路を巻装する。この上に絶縁テープ４を巻いた後、さらに他方の巻線ｎ１２の他方の線路を逆巻きで巻き、その上に絶縁テープ４を巻く。そして、コイルボビン１の一端側に位置する都合４つの端部を半田付けで相互に接続した端部ロをセンタタップとし、コイルボビン４の他端側に位置する都合４つの端部のうち、巻線ｎ１１である２つの端部と巻線ｎ１２である２つの端部を夫々半田付けで接続し、端点イ，ハを形成する。なお、各巻線ｎ１１，ｎ１２の各線路は１本の導線を用いて折り返すようにして巻くようにしてもよい。
【００３７】
いずれにしても、各巻線ｎ１１，ｎ１２の各線路のコイルボビン１に対する巻き始め位置を同じとすることで、端点イ、ハ及びセンタタップとなる端部ロはコイルボビン１の周方向における同一位置に位置させることができる。
【００３８】
２次巻線ｎ２１，２２も同様に図９に示すように巻き始め位置を同じとして総計４層を順次巻装し、端点ニ、ヘ及びセンタタップとなる端部ホを形成する。１次巻線ｎ１１の巻き始め位置及び２次巻線ｎ１２の巻き始め位置を揃えることで、上記イ〜ヘを同じ位置とすることができる。
【００３９】
センタタップとなる端部ロ、ホの少なくとも一方を、図１０に示すように、コイルボビン１の中央側に位置させてもよい。
【００４０】
図１１に示すように、プリント板への取付用のピン７０を備えた台座７がコイルボビン１に連結される場合は、各端点及びセンタタップは上記ピン７０に接続すればよい。
【００４１】
いわゆるサンドイッチ巻きとしない場合においても、図１２に示すように、巻き始めを同じとして一方の巻線ｎ１１（またはｎ２１）と他方の巻線ｎ１２（またはｎ２２）を順次巻いて、一端側に端点イ、ハ（またはニ、ヘ）、他端側にセンタタップとなる端部ロ（またはホ）を形成すればよい。
【００４２】
（第６の実施の形態）
本実施形態では、図１３に示すように、センタタップとなる端部ロを最終的にコイルボビン１の外周を通して端点イ、ハが位置する側に配置している。
【００４３】
図１４に示すように、各層毎に端点をコイルボビン１の一端側に引き出すようにしてもよい。ただし、この場合は絶縁テープ４を巻かなくてはならない回数が増えるために、コンパクト化の点では図１３に示すようにした方が好ましい。
【００４４】
（第７の実施の形態）
図１５及び図１６に示すように、１次巻線ｎ１１，ｎ１２のコイルボビン１と２次巻線ｎ２１，ｎ２２のコイルボビン１とを別体としている場合は、各巻線を簡単に巻くことができ、また、台座７に両コイルボビン１，１を連結することで一体化したり、第３の実施形態に示したもののようにすることもできる。
【００４５】
【発明の効果】
請求項１の発明は、コアの異なる部位に巻装された１次巻線と２次巻線との少なくとも一方がセンタタップと各一端との間の２つの巻線からなるトランスであって、前記センタタップと各一端との間の２つの巻線が夫々並列接続された複数本の線路からなり、各線路が１つの層となるとともに、センタタップと各一端との間の各巻線の層が交互に重なるようにコイルボビンに巻装されているものであり、一方の巻線を形成する２つの層間に他方の巻線を形成する層が挿入されるから、１つの巻線における層間の近接効果が抑制されることによって損失が低減することになる。すなわち、トランスでの損失が少なくなり、巻線による発熱が低減してトランスの小型化が可能になる。
【００４６】
請求項２の発明は、前記１次巻線のみにおいてセンタタップと各一端との間の２つの巻線の層が交互に重なるようにコイルボビンに巻装されているものであり、２次巻線については従来と同様の巻き方を採用することで、１次巻線での近接効果によって生じる損失を低減しながらも、２次巻線については従来の技術を適用することができるから、巻装作業が比較的簡単であって、所要の効果を得ながらもコスト増を抑制することができる。
【００４７】
請求項３の発明は、請求項１の発明において、前記１次巻線と前記２次巻線との両方がセンタタップを有し、それぞれのセンタタップと各一端との間の２つの巻線の層が交互に重なるようにコイルボビンに巻装されているものであり、１次巻線と２次巻線との両方について近接効果による損失を低減することができるから、トランスでの損失が少なくなり、巻線による発熱が一層低減してトランスの小型化につながる。
【００４８】
請求項４の発明は、請求項２の発明において、前記１次巻線と前記２次巻線との両方がセンタタップを有し、２次巻線における２つの巻線が１次巻線を両側から挟む形で配置されているものであり、１次巻線と２次巻線との結合度が高くなり漏れ磁束が少なくなってトランスでの損失を一層低減することができる。
【００４９】
請求項５の発明は、請求項１ないし請求項４の発明において、前記コアは２つのＥ型コアを組み合わせた日字状に形成されているものであり、磁気抵抗の少ない磁路を形成することができ、損失の一層少ないトランスを提供することができる。
【００５０】
請求項６の発明は、請求項１ないし請求項３の発明において、前記１次巻線を磁路の一部が開放された第１のコアに巻装した第１のトランス半体と、前記２次巻線を磁路の一部が開放された第２のコアに巻装した第２のトランス半体とを備え、第１および第２のコアにおいて磁路の開放されている部位同士を突き合わせる形で第１および第２のトランス半体を分離可能に対向配置するものであり、端子を設けることなく無接点で電力を伝達することができるから、端子の腐食による故障が発生せず、防水性や防塵性を要求される環境での使用に適したものになる。
【００５１】
請求項７の発明は、請求項１ないし請求項６の発明において、少なくとも１つの層は撚り線を巻装して形成されているものであり、近接効果が少ないのはもちろんのこと、高周波で使用する際の表皮効果の影響も低減できるから、高周波での損失の少ないトランスを提供することができる。
【００５２】
請求項８の発明は、請求項１ないし請求項７の発明において、前記コイルボビンにおいて各巻線を巻装する領域がそれぞれ仕切られ、各巻線を巻装する領域を埋めて隙間を形成しないようにセンタタップと各一端との間の２つの巻線の層が巻装されているものであり、各層が隙間なく巻装されていることによって、磁束の漏れが少なくなり、漏れ磁束による損失を低減することができる。
【００５３】
請求項９の発明は、請求項１の発明において、センタタップと各一端との間の２つの巻線はそのセンタタップ側の各端部がコイルボビンの一方側に、センタタップ側でない端部をコイルボビンの他方側に位置して２つの巻線のセンタタップ側の端部がセンタタップに接続されているものであり、センタタップ接続させる巻線の端点をコイルボビンの一方側に集めるために、センタタップ配線を短くすることができ、トランス巻線の体積密度をあげるとともにノイズを低減させることができる。
【００５４】
請求項１０の発明は、請求項９の発明において、センタタップと各一端との間の２つの巻線のコイルボビンに対する巻き始め位置が同じとなっているものであり、巻線を巻く時の位置調整が簡単になる上に、回路への接続のための配線を短くすることができ、トランス巻線の体積密度をあげるとともに特性を向上させることができ、ノイズを低減させることができる。
【００５５】
請求項１１の発明は、請求項９または請求項１０の発明において、次巻線用のコイルボビンと２次巻線用のコイルボビンとが独立しているとともに、これらコイルボビンは外部接続用ピンを備えた台座に連結されて上記ピンに巻線が接続されているものであり、プリント板への取付を容易にすることができる。
【００５６】
請求項１２の発明は、コアの異なる部位に巻装された１次巻線と２次巻線との少なくとも一方がセンタタップと各一端との間の２つの巻線からなるとともに、センタタップと各一端との間の上記２つの巻線が、並列接続された複数本の線路からなるトランスの製造方法であって、センタタップと各一端との間の上記２つの巻線である第１の巻線と第２の巻線のうちの第１の巻線の第１の線路をコイルボビンに巻き、ついで第１の巻線の第１の線路の外周に第２の巻線の第１の線路を逆巻きで巻き、この後、第２の巻線の第１の線路の外周に第１の巻線の第２の線路を巻き、さらに第１の巻線の第２の線路の外周に第２の巻線の第２の線路を巻いて、上記４つの線路のコイルボビンの一方側に位置する各端部をセンタタップに接続し、コイルボビンの他方側に位置する第１の巻線の２つの線路の各端部と第２の巻線の２つの線路の各端部とを夫々相互に接続するものであり、いわゆるサンドイッチ巻きとした請求項１の発明にかかるものを容易に製造することができる。
【００５７】
請求項１３の発明は、請求項１２の発明において、巻線の各端部はコイルボビンに設けたプリント板取付用のピンに接続するものであり、請求項１１に係るものを容易に製造することができる。
【００５８】
請求項１４の発明は、センタタップと各一端との間の２つの巻線の各線路をコイルボビンに対して同一位置から巻き始めるものであり、請求項１及び請求項１０の発明に係るものを容易に製造することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態を示す断面図である。
【図２】同上の要部断面図である。
【図３】同上における巻線の巻装例を示す図である。
【図４】本発明の第２の実施の形態における巻線の巻装例を示す図である。
【図５】本発明に他の構成例を示す概略構成図である。
【図６】本発明の第３の実施の形態を示す断面図である。
【図７】本発明の第４の実施の形態を示す概略断面図である。
【図８】本発明の第５の実施の形態における製造手順を示す説明図である。
【図９】同上の製造手順を示す説明図である。
【図１０】同上の他例を示す概略構成図である。
【図１１】同上のさらに他例を示す概略構成図である。
【図１２】同上の別の例の製造手順を示す説明図である。
【図１３】本発明の第６の実施の形態における製造手順を示す説明図である。
【図１４】同上の他例の製造手順を示す説明図である。
【図１５】本発明の第７の実施の形態を示す概略構成図である。
【図１６】（ａ）は同上のコイルボビンと台座の側面図、（ｂ）は同上の水平断面図、（ｃ）は側面図である。
【図１７】トランスを用いたスイッチング電源の一例を示す回路図である。
【図１８】従来のトランスの構成例を示す断面図である。
【符号の説明】
１コイルボビン
２ａ，２ｂ鍔部
２ｃ〜２ｅ分離鍔
３コア
３ａ，３ｂＥ型コア
ｎ１１次巻線
ｎ２２次巻線
ｎ１１，ｎ１２巻線
ｎ２１，ｎ２２巻線
Ｔトランス
Ｔ１，Ｔ２トランス半体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transformer used in a push-pull type power supply circuit.
[0002]
[Prior art]
In general, a push-pull type (also referred to as a center tap type) switching power supply circuit uses a transformer T having a center tap in each of a primary winding n1 and a secondary winding n2, as shown in FIG. This power supply circuit includes two switching elements Q1 and Q2 that are alternately turned on and off at high frequencies (generally several tens of kHz) by the control circuits CN1 and CN2. Both switching elements Q1 and Q2 are connected in common at one end (in the example shown, MOSFETs are used as switching elements Q1 and Q2 and the sources are connected in common), and each other end is a primary winding of a transformer T, respectively. It is connected to each end of the line n1. The center tap of the primary winding n1 is connected to one output end (positive in the illustrated example) of the DC power source DC, and the one end of the switching elements Q1 and Q2 is the other output end (negative in the illustrated example) of the DC power source DC. Connected to. Capacitors C1 and C2 are connected between one end of the primary winding of the transformer T and the center tap, respectively. Capacitors C1 and C2 constitute a resonant circuit together with the leakage inductance of transformer T, and enable zero-volt switching of switching elements Q1 and Q2.
[0003]
The anodes of the diodes D1 and D2 are connected to both ends of the secondary winding n2 of the transformer T, respectively. The cathodes of the diodes D1 and D2 are connected in common and output a pulsating voltage between the center tap of the secondary winding n2 of the transformer T. That is, the full-wave rectifier circuit is configured by the secondary winding n2 of the transformer T and the diodes D1 and D2. The output of the full-wave rectifier circuit is supplied to a load Z through a choke input type filter circuit including an inductor L and a capacitor C.
[0004]
Thus, when the switching elements Q1 and Q2 are alternately turned on and off, current flows alternately between each end of the primary winding n1 and the center tap, and the secondary winding n2 has the primary winding n1. An alternating voltage is generated according to the direction of the flowing current. That is, in the primary winding n1, current always flows through only one of the two windings n11 and n12 between the center tap and one end, and current does not flow simultaneously. In this way, DC-AC conversion is performed, and the alternating voltage generated in the secondary winding n2 of the transformer T is rectified and converted into a DC voltage by passing through a filter circuit. Is done.
[0005]
By the way, in order to use the leakage inductance as the resonance inductance as described above, the primary winding n1 and the secondary winding n2 are not completely coupled, but are divided and the primary windings n1 and 2 are divided. An air gap is formed in the core 3 that forms a magnetic path with the next winding n2. As described above, since the primary winding n1 and the secondary winding n2 each have a center tap, the primary winding n1 and the secondary winding n2 are each between the center tap and one end. 2 windings n11, n12, n21, n22, and in order to split the primary winding n1 and the secondary winding n2, the windings n11, n12, n21, n22 Is considered to have the positional relationship shown in FIG. 18 (Japanese Patent Laid-Open No. 63-211711).
[0006]
That is, the one shown in FIG. 18A is provided with flanges 2a and 2b at both ends in the longitudinal direction of the coil bobbin 1, and one split flange 2c is formed at the middle in the longitudinal direction. Two windings n11 and n12 that form the primary winding n1 are wound in order between the split rod 2c and the secondary winding n2 is formed between the flange portion 2b and the split rod 2c. Two windings n21 and n22 are stacked in order. 18 (b) shows that two split rods 2d and 2e are formed in the middle portion in the longitudinal direction of the coil bobbin 1, and the primary winding n1 is between the rib portion 2a and the divided rod 2d. One winding n11 is wound, the other winding n12 of the primary winding n1 is wound between the flange portion 2b and the split rod 2e, and the secondary winding is further sandwiched between the two divided rods 2d and 2e. The windings n21 and n22 of the line n2 are wound in an overlapping manner. In FIG. 18C, three split rods 2f to 2h are formed in the middle portion of the coil bobbin 1 in the longitudinal direction, and windings n11, n12, n21, and n22 are wound around the divided portions, respectively. It is.
[0007]
[Problems to be solved by the invention]
By the way, in the transformer T described above, a loss greater than the loss calculated from the current flowing through the winding and the resistance of the winding occurs. One cause of this loss is that the primary winding n1 and the secondary winding n2 are not completely coupled in order to use the leakage inductance as a resonance inductance. It is thought that the influence of the proximity effect due to the flow of the high-frequency current is large. That is, to reduce the loss in the transformer T, it is required to reduce the influence of the proximity effect.
[0008]
The present invention has been made in view of the above reasons, and an object thereof is to provide a transformer with reduced loss.
[0009]
[Means for Solving the Problems]
The invention of claim 1 is a transformer in which at least one of a primary winding and a secondary winding wound around different parts of a core is composed of two windings between a center tap and one end, Above Between the center tap and each end Two windings Respectively It consists of multiple lines connected in parallel, and each line becomes one layer, Between the center tap and each end It is wound around the coil bobbin so that the layers of each winding are alternately overlapped.
[0010]
The invention of claim 2 is the invention of claim 1, wherein only the primary winding is used. Between the center tap and each end It is wound around the coil bobbin so that the layers of the two windings are alternately overlapped.
[0011]
According to a third aspect of the present invention, in the first aspect of the invention, both the primary winding and the secondary winding have center taps, Between the center tap and each end It is wound around the coil bobbin so that the layers of the two windings are alternately overlapped.
[0012]
According to a fourth aspect of the present invention, in the second aspect of the invention, both the primary winding and the secondary winding have center taps, and two windings in the secondary winding are primary windings. It is arranged so as to be sandwiched from both sides.
[0013]
According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the core is formed in a letter shape combining two E-type cores.
[0014]
According to a sixth aspect of the present invention, in the first to third aspects of the present invention, a first transformer half body in which the primary winding is wound around a first core having a part of a magnetic path opened, and A second transformer half that winds a secondary winding around a second core having a part of the magnetic path opened, and the portions of the first and second cores where the magnetic path is opened The first and second transformer halves are arranged to face each other so as to be separated from each other.
[0015]
The invention of claim 7 is the invention of claims 1 to 6, wherein at least one layer is formed by winding a stranded wire.
[0016]
According to an eighth aspect of the present invention, in the first to seventh aspects of the present invention, in the coil bobbin, a region where each winding is wound is partitioned, and a region where each winding is wound is filled so as not to form a gap. Two winding layers between the center tap and each end Is wound.
[0017]
The invention of claim 9 In the invention of claim 1, the above Two windings between the center tap and each end Is Each end on the center tap side is located on one side of the coil bobbin, the end on the non-center tap side is located on the other side of the coil bobbin, and the center tap side ends of the two windings are connected to the center tap It is.
[0018]
The invention of claim 10 is the invention of claim 9, Between the center tap and each end The winding start positions of the two windings with respect to the coil bobbin are the same.
[0019]
The invention of claim 11 is the invention of claim 9 or claim 10, wherein the coil bobbin for the next winding and the coil bobbin for the secondary winding are independent, and these coil bobbins are provided with external connection pins. It is connected to a pedestal and a winding is connected to the pin.
[0020]
According to the invention of claim 12, at least one of the primary winding and the secondary winding wound around different parts of the core includes two windings between the center tap and each one end. , Above the center tap and each end A method of manufacturing a transformer comprising a plurality of lines in which two windings are connected in parallel, Of the two windings between the center tap and one end, the first winding and the second winding The first line of the first winding is wound around the coil bobbin, then the first line of the second winding is wound around the outer periphery of the first line of the first winding by reverse winding, and then the second line Winding the second line of the first winding around the outer periphery of the first line of the winding, and winding the second line of the second winding around the outer periphery of the second line of the first winding , Each end located on one side of the coil bobbin of the four lines is connected to the center tap, and each end of the two lines of the first winding located on the other side of the coil bobbin and the second winding Each end of the two lines is connected to each other.
[0021]
According to a thirteenth aspect of the present invention, in the twelfth aspect of the invention, each end of the winding is connected to a printed board mounting pin provided on the coil bobbin.
[0022]
The invention of claim 14 Two between the center tap and each end Each line of the winding starts to be wound from the same position around the coil bobbin.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
In the following embodiment, a transformer T used in the switching power supply circuit shown in FIG. 8 is shown.
[0024]
(First embodiment)
In the present embodiment, basically, as shown in FIG. 1, in the longitudinal direction of the coil bobbin 1, a region for winding the primary winding n1 and a region for winding the secondary winding n2 are formed. The two windings n11 and n12 forming the next winding n1 and the two windings n21 and n22 forming the secondary winding n2 are so-called sandwich windings. Sandwich winding is a winding method in which different windings are alternately wound one by one when two windings are multi-layer windings. The core 3 is a Japanese character EE type core that is a combination of two E type cores 3a and 3b. The central piece of the E type cores 3a and 3b is inserted into the coil bobbin 1 to perform the primary winding. A magnetic path is formed so as to surround the primary winding n1 and the secondary winding n2 with the remaining portions of the E-type cores 3a and 3b through the centers of n1 and the secondary winding n2. Here, in order to obtain the leakage magnetic flux, an air gap is formed at the butt portion of the E-type cores 3a and 3b.
[0025]
More specifically, as shown in FIG. 2, the coil bobbin 1 has primary windings by forming flanges 2a and 2b at both ends in the longitudinal direction and split flanges 2c at the intermediate part. It is divided into a region where n1 is wound and a region where the secondary winding n2 is wound, and two windings n11 forming the primary winding n1 between the flange portion 2a and the divided flange 2c. , N12 are alternately wound one layer at a time. Here, after one winding n11 is wound by one layer with close winding, the insulating tape 4 is wound around the outer periphery of the winding n11, and the other winding n12 is wound by one layer outside the insulating tape 4. Is done. Further, the insulating tape 4 is wound around the outside of the winding n12, and the one winding n11 is wound around the outside of the insulating tape 4. The two windings n11 and n12 are alternately wound one layer at a time in the same procedure. In the illustrated example, the windings n11 and n12 are wound in four layers, and each layer is wound as shown in FIG. 3, and the end points of the respective layers denoted by the same reference numerals in FIG. 3 are connected to each other. That is, the layers forming the same winding n11, n12, n21, n22 are connected in parallel to each other, and the end points that are the center taps of the different windings n11, n12, n21n22 are connected to each other. That is, in the illustrated example, the primary winding n1 and the secondary winding n2 are each divided into a plurality of lines connected in parallel, and the windings n11, n12, n21, and n22 are different in a form in which each line is formed as one layer. They are wound in layers. Thus, the end point B becomes the center tap, the end point A becomes one end of the winding n11, and the end point C becomes one end of the winding n12. The secondary winding n2 is similarly wound.
[0026]
Therefore, for example, if the cross-sectional area of the winding n11 is S and the windings wound as the first layer and the third layer have the same diameter, the cross-sectional area of the winding per layer is S / 2. become. The same applies to the other windings n12, n21, and n22.
[0027]
In the above-described push-pull type switching power supply circuit, since no current flows through the windings n11 and n12 of the primary winding n1, there is almost no interaction between the two windings n11 and n12. In addition, there is a layer forming the other winding n11, n12, n21, n22 between the layers forming the windings n11, n12, n21, n22 (for example, between the layers of the winding n11, the winding n12 The effect of the proximity action between the layers of one winding n11, n12, n21, n22 is reduced. That is, one winding n11, n12, n21, n22 is divided into a plurality of lines connected in parallel to form a layer on each line, and layers of other windings n11, n12, n21, n22 between the layers. By interposing, the influence of the proximity effect can be reduced. On the other hand, the primary winding n1 and the secondary winding n2 are respectively wound in different regions divided by the dividing rod 2c in the coil bobbin 1, and an air gap is formed in the core. A leakage inductor can be used.
[0028]
In the configuration example described above, one winding n11, n12, n21, n22 is divided into two lines, but may be divided into three or more lines. Moreover, when dividing, the cross-sectional area of each line does not necessarily have to be equal. For example, when the total cross-sectional area is S, in the case of two divisions, one cross-sectional area may be S / 3, and the other cross-sectional area may be 2S / 3.
[0029]
(Second Embodiment)
In this embodiment, as shown in FIG. 4A, a line obtained by dividing the windings n11, n12, n21, and n22 is further formed by two strands, and both strands are wound around the coil bobbin 1 at the same time. (In short, both windings n11, n12, n21, n22 are bifilar windings). This is because, for the reason that the number of turns per layer is small, a portion of the coil bobbin 1 where the primary winding n1 or the secondary winding n2 is wound is not wound in the coil bobbin 1 as shown in FIG. It is effective when it occurs, and a plurality of lines are wound in one layer at the same time so that both ends of a region where the winding is wound are filled.
[0030]
The configuration of the present embodiment can also be realized by using a litz wire twisted with a thin wire instead of using a normal single wire. In addition, when a stranded wire such as a litz wire is used, the influence of the skin effect can be reduced. The winding may be made of a material having a circular cross section such as a copper foil, instead of a circular material having a circular cross section such as a general copper wire. Other configurations and operations are the same as those in the first embodiment.
[0031]
In the configuration example described above, the core 3 is a combination of the E-type core 3a. However, as shown in FIG. 5, a combination of two U-type cores 3c and 3d is formed so as to form a square shape as a whole. A core 3 of the form may be used. In this case, the primary winding n1 is wound around the butted portion of one leg piece of each U-shaped core 3c, 3d, and the secondary winding n2 is wound around the butted portion of the other leg piece.
[0032]
(Third embodiment)
In the present embodiment, as shown in FIG. 6, the primary winding n1 and the secondary winding n2 are housed in separate housings 5a and 5b. That is, the coil bobbins 1a and 1b having the shape obtained by dividing the coil bobbin 1 used in the first embodiment into two parts at the part of the separation rod 2c are used, and the windings n11 and n12 of the primary winding n1 are wound around one coil bobbin 1a. Windings n21 and n22 of the secondary winding n2 are wound around the other coil bobbin 1b. The winding method of the primary winding n1 and the secondary winding n2 is the same as that of the first embodiment, and each winding n11, n12, n21, n22 is divided into a plurality of lines connected in parallel. Then, a layer is formed for each line, and another winding layer is interposed between layers of one winding to form a multilayer winding. Further, two E-type cores 3a are used for the core 3, and each E-type core 3a is disposed in each of the housings 5a and 5b. That is, the transformer halves T1 and T2 constituting half of the transformer T are accommodated in the respective housings 5a and 5b.
[0033]
A recess 6 is formed in the housing 5a for housing the transformer half T1 around which the primary winding n1 is wound. The center piece of the E-shaped core 3a and the tip surfaces of both side pieces of the transformer half T1 are the recesses 6. Arranged as desired on the bottom. The housing 5b houses a transformer half T2 around which the secondary winding n2 is wound. The center piece and both end pieces of the transformer half T2 are aligned with the center piece and both side pieces of the transformer half T1. In this case, a part of the housing 5b is fitted into the recess 6 provided in the housing 5a. The magnetic path is open at the tip surface of each E-type core 3a, 3b, and when the housing 5b is fitted into the recess 6 of the housing 5a, the magnetic path is opened at each E-type core 3a, 3b. Both transformer halves T1 and T2 are arranged to face each other in such a manner that they face each other. Therefore, both transformer halves T1 and T2 are transformer-coupled so that power can be transmitted from the primary winding n1 to the secondary winding n2.
[0034]
According to the above-described configuration, since the transformer halves T1 and T2 can be transmitted between the housings 5a and 5b without exposing the transformer halves T1 and T2 to the outside of the housings 5a and 5b, the housings 5a and 5b are sealed. However, it becomes possible to supply power from the housing 5a to the housing 5b, which is suitable for supplying power in an environment where waterproofness and dustproofness are required such as in a bathroom or outdoors. Other configurations and operations are the same as those in the first embodiment.
[0035]
(Fourth embodiment)
In the present embodiment, the leakage inductance is reduced. As shown in FIG. 7, the coil bobbin 1 is provided with flanges 2a and 2b at both ends in the longitudinal direction, as shown in FIG. 18B. By using two separation rods 2d and 2e in the middle portion in the longitudinal direction, three regions for winding the windings are used. In the central region, the windings n11 and n12 of the primary winding n1 are alternately layered and wound in a multi-layer winding, and in the regions on both sides, the windings n21 and n22 of the secondary winding n2 are respectively wound. It is. In this configuration, by arranging the secondary winding n2 on both sides of the primary winding n1, most of the magnetic flux generated in the primary winding n1 passes through the secondary winding n2. Compared with the configuration of the embodiment, the leakage magnetic flux is reduced. Other configurations and operations are the same as those in the first embodiment.
[0036]
(Fifth embodiment)
The embodiment shown in FIG. 8 shows in detail the winding of the windings n11 and n12 in the first embodiment, and one line of one winding n11 is wound by one layer with close winding. Later, the insulating tape 4 is wound around the outer periphery of the winding n11, and one line of the other winding n12 is wound around the outer side of the insulating tape 4 by reverse winding. Further, the insulating tape 4 is wound around the outside of the winding n12, and the other line of the one winding n11 is wound around the outside of the insulating tape 4. After the insulating tape 4 is wound thereon, the other line of the other winding n12 is wound in the reverse direction, and the insulating tape 4 is wound thereon. Then, an end B connecting the four end portions located on one end side of the coil bobbin 1 with each other by soldering is used as a center tap, and the winding of the four end portions located on the other end side of the coil bobbin 4 is wound. The two ends that are n11 and the two ends that are the winding n12 are connected by soldering to form the end points A and C. Note that each line of the windings n11 and n12 may be wound using a single conductor.
[0037]
In any case, by making the winding start positions of the respective windings n11 and n12 with respect to the coil bobbin 1 the same, the end points A, C, and the end portion B serving as the center tap are positioned at the same position in the circumferential direction of the coil bobbin 1. Can be made.
[0038]
Similarly, as shown in FIG. 9, the secondary windings n21 and 22 are sequentially wound with a total of four layers at the same winding start position, thereby forming end points d, f and a center tap. By aligning the winding start position of the primary winding n11 and the winding start position of the secondary winding n12, the above-mentioned A to F can be made the same position.
[0039]
As shown in FIG. 10, at least one of the end b and ho that become the center tap may be positioned on the center side of the coil bobbin 1.
[0040]
As shown in FIG. 11, when a pedestal 7 having a pin 70 for attachment to a printed board is coupled to the coil bobbin 1, each end point and center tap may be connected to the pin 70.
[0041]
Even when the so-called sandwich winding is not used, as shown in FIG. 12, one winding n11 (or n21) and the other winding n12 (or n22) are sequentially wound at the same winding start, and the end point , C (or d, f), and an end b (or e) serving as a center tap may be formed on the other end side.
[0042]
(Sixth embodiment)
In the present embodiment, as shown in FIG. 13, the end b serving as the center tap is finally arranged on the side where the end points i and c are located through the outer periphery of the coil bobbin 1.
[0043]
As shown in FIG. 14, the end point may be pulled out to one end side of the coil bobbin 1 for each layer. However, in this case, since the number of times that the insulating tape 4 must be wound increases, it is preferable to make it as shown in FIG.
[0044]
(Seventh embodiment)
As shown in FIGS. 15 and 16, when the coil bobbin 1 of the primary windings n11 and n12 and the coil bobbin 1 of the secondary windings n21 and n22 are separated, each winding can be easily wound. Further, the two coil bobbins 1 and 1 can be connected to the pedestal 7 so as to be integrated or as shown in the third embodiment.
[0045]
【The invention's effect】
The invention of claim 1 is a transformer in which at least one of a primary winding and a secondary winding wound around different parts of a core is composed of two windings between a center tap and one end, Above Between the center tap and each end Two windings Respectively It consists of multiple lines connected in parallel, and each line becomes one layer, Between the center tap and each end Since each winding layer is wound around the coil bobbin so as to overlap each other, a layer forming the other winding is inserted between two layers forming one winding, so that one winding Loss is reduced by suppressing the proximity effect between the layers. That is, loss in the transformer is reduced, heat generation by the winding is reduced, and the transformer can be downsized.
[0046]
The invention of claim 2 is only for the primary winding. Between the center tap and each end It is wound around the coil bobbin so that the layers of the two windings are alternately overlapped. By adopting the same winding method as the conventional winding for the secondary winding, the proximity effect in the primary winding Since the conventional technology can be applied to the secondary winding while reducing the loss generated, the winding operation is relatively simple, and the increase in cost can be suppressed while obtaining the required effect. it can.
[0047]
According to a third aspect of the present invention, in the first aspect of the invention, both the primary winding and the secondary winding have center taps, Between the center tap and each end Since the layers of the two windings are wound around the coil bobbin so as to overlap each other, the loss due to the proximity effect can be reduced for both the primary winding and the secondary winding. Loss is reduced, and heat generated by the windings is further reduced, leading to miniaturization of the transformer.
[0048]
According to a fourth aspect of the present invention, in the second aspect of the invention, both the primary winding and the secondary winding have center taps, and two windings in the secondary winding are primary windings. It is arranged so as to be sandwiched from both sides, and the degree of coupling between the primary winding and the secondary winding is increased, the leakage magnetic flux is reduced, and the loss in the transformer can be further reduced.
[0049]
According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the core is formed in a letter shape combining two E-shaped cores, and forms a magnetic path with a small magnetic resistance. And a transformer with less loss can be provided.
[0050]
According to a sixth aspect of the present invention, in the first to third aspects of the present invention, a first transformer half body in which the primary winding is wound around a first core having a part of a magnetic path opened, and A second transformer half that winds a secondary winding around a second core having a part of the magnetic path opened, and the portions of the first and second cores where the magnetic path is opened The first and second transformer halves are arranged so as to face each other in a butting manner, and power can be transmitted in a contactless manner without providing a terminal, so that failure due to corrosion of the terminal does not occur. It is suitable for use in environments where waterproofness and dustproofness are required.
[0051]
According to a seventh aspect of the present invention, in the first to sixth aspects of the present invention, at least one layer is formed by winding a stranded wire, and the proximity effect is small, as well as at a high frequency. Since the influence of the skin effect at the time of use can also be reduced, a transformer with less loss at high frequencies can be provided.
[0052]
According to an eighth aspect of the present invention, in the first to seventh aspects of the present invention, in the coil bobbin, a region where each winding is wound is partitioned, and a region where each winding is wound is filled so as not to form a gap. Two winding layers between the center tap and each end Since each layer is wound without a gap, leakage of magnetic flux is reduced, and loss due to leakage magnetic flux can be reduced.
[0053]
The invention of claim 9 In the invention of claim 1, the two windings between the center tap and each one end are Each end on the center tap side is located on one side of the coil bobbin, the end on the non-center tap side is located on the other side of the coil bobbin, and the center tap side ends of the two windings are connected to the center tap Since the end points of the windings to be connected to the center tap are collected on one side of the coil bobbin, the center tap wiring can be shortened, and the volume density of the transformer winding can be increased and noise can be reduced.
[0054]
The invention of claim 10 is the invention of claim 9, Between the center tap and each end The winding start position of the two windings with respect to the coil bobbin is the same, and the position adjustment when winding the winding is simplified, and the wiring for connection to the circuit can be shortened, The volume density of the transformer winding can be increased and the characteristics can be improved, and noise can be reduced.
[0055]
The invention of claim 11 is the invention of claim 9 or claim 10, wherein the coil bobbin for the next winding and the coil bobbin for the secondary winding are independent, and these coil bobbins are provided with external connection pins. The winding is connected to the pin connected to the pedestal and can be easily attached to the printed board.
[0056]
According to the invention of claim 12, at least one of the primary winding and the secondary winding wound around different parts of the core includes two windings between the center tap and each one end. , Above the center tap and each end A method of manufacturing a transformer comprising a plurality of lines in which two windings are connected in parallel, Of the two windings between the center tap and one end, the first winding and the second winding The first line of the first winding is wound around the coil bobbin, then the first line of the second winding is wound around the outer periphery of the first line of the first winding by reverse winding, and then the second line Winding the second line of the first winding around the outer periphery of the first line of the winding, and winding the second line of the second winding around the outer periphery of the second line of the first winding , Each end located on one side of the coil bobbin of the four lines is connected to the center tap, and each end of the two lines of the first winding located on the other side of the coil bobbin and the second winding Each end of the two lines is connected to each other, and what is called a sandwich winding can be easily manufactured.
[0057]
According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention, each end of the winding is connected to a printed board mounting pin provided on the coil bobbin, and the one according to the eleventh aspect is easily manufactured. Can do.
[0058]
The invention of claim 14 Two between the center tap and each end Each line of the winding starts to be wound from the same position with respect to the coil bobbin, and the ones according to the inventions of claims 1 and 10 can be easily manufactured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the main part of the above.
FIG. 3 is a diagram showing a winding example of the winding in the above.
FIG. 4 is a diagram showing a winding example of a winding according to a second embodiment of the present invention.
FIG. 5 is a schematic configuration diagram showing another configuration example according to the present invention.
FIG. 6 is a cross-sectional view showing a third embodiment of the present invention.
FIG. 7 is a schematic sectional view showing a fourth embodiment of the present invention.
FIG. 8 is an explanatory diagram showing a manufacturing procedure in the fifth embodiment of the present invention.
FIG. 9 is an explanatory view showing the manufacturing procedure of the above.
FIG. 10 is a schematic block diagram showing another example of the above.
FIG. 11 is a schematic configuration diagram showing still another example of the above.
FIG. 12 is an explanatory view showing another example of the manufacturing procedure.
FIG. 13 is an explanatory diagram showing a manufacturing procedure in the sixth embodiment of the present invention.
FIG. 14 is an explanatory diagram showing a manufacturing procedure of another example of the above.
FIG. 15 is a schematic configuration diagram showing a seventh embodiment of the present invention.
16A is a side view of the coil bobbin and the pedestal, FIG. 16B is a horizontal sectional view of the same, and FIG. 16C is a side view.
FIG. 17 is a circuit diagram showing an example of a switching power supply using a transformer.
FIG. 18 is a cross-sectional view showing a configuration example of a conventional transformer.
[Explanation of symbols]
1 Coil bobbin
2a, 2b buttock
2c ~ 2e Separation basket
3 core
3a, 3b E type core
n1 Primary winding
n2 secondary winding
n11, n12 winding
n21, n22 winding
T transformer
T1, T2 Transformer half

Claims

At least one of a primary winding and a secondary winding wound around different parts of the core is a transformer composed of two windings between a center tap and each end, and the center tap and each end two windings consists plurality of lines which are respectively connected in parallel, with each line corresponds to one of the layers, the coil bobbin as layers of windings between the center tap and each one overlaps alternate between A transformer characterized by being wound around.

2. The transformer according to claim 1, wherein only the primary winding is wound around a coil bobbin so that two winding layers between the center tap and each one end are alternately overlapped.

Both the primary winding and the secondary winding have center taps, and are wound around the coil bobbin so that the layers of the two windings between the respective center taps and each one end overlap each other. The transformer according to claim 1, wherein:

Both the primary winding and the secondary winding have a center tap, and two windings in the secondary winding are arranged so as to sandwich the primary winding from both sides. The transformer according to claim 2.

The transformer according to any one of claims 1 to 4, wherein the core is formed in a letter shape combining two E-shaped cores.

A first transformer half in which the primary winding is wound around a first core having a part of the magnetic path open; and a second core in which the secondary winding has a part of the magnetic path open. A second transformer half wound around the first and second cores in such a manner that the first and second transformer halves face each other in a form where the magnetic path is opened. transformer according to any one of claims 1 to 3, characterized in that arranged.

At least one layer transformer according to any one of claims 1 to 6, characterized in that it is formed by winding the strands.

In the coil bobbin, the region where each winding is wound is partitioned, and two winding layers between the center tap and each one end are wound so as not to fill the region where each winding is wound and to form a gap. transformer according to any one of claims 1 to 7, characterized in that is.

Two windings on one side of each end of the center tap side coil bobbin between each end and the center tap, the end not center tap side located on the other side of the coil bobbin of the two windings The transformer according to claim 1, wherein an end on the center tap side is connected to the center tap.

10. The transformer according to claim 9, wherein the winding start positions of the two windings between the center tap and each one end with respect to the coil bobbin are the same.

The coil bobbin for primary winding and the coil bobbin for secondary winding are independent, and these coil bobbins are connected to a pedestal provided with external connection pins and the windings are connected to the pins. The transformer according to claim 9 or 10, characterized in that

At least one of the primary winding and the secondary winding wound around different parts of the core is composed of two windings between the center tap and each one end, and the above-mentioned between the center tap and each one end A method of manufacturing a transformer comprising a plurality of lines connected in parallel with two windings, wherein the first winding and the second winding are the two windings between the center tap and each end. winding the first line of the first winding of the line in the coil bobbin, then winding in reverse winding the first line of the second winding to the outer periphery of the first line of the first winding, after the The second winding of the first winding is wound around the outer periphery of the first winding of the second winding, and the second winding of the second winding is wound around the outer circumference of the second winding of the first winding. Wrap the track, connect each end located on one side of the coil bobbin of the above four tracks to the center tap, and locate it on the other side of the coil bobbin The method of manufacturing a transformer, characterized by connecting the first winding two lines each end of the two lines at each end and the second winding of the respective other.

13. A transformer manufacturing method according to claim 12, wherein each end of the winding is connected to a printed board mounting pin provided on the coil bobbin.

14. The method of manufacturing a transformer according to claim 12, wherein each line of the two windings between the center tap and each one end starts to be wound from the same position with respect to the coil bobbin.