JP2004114092A

JP2004114092A - Electromagnetic welding set using semiconductor switch and welding transformer

Info

Publication number: JP2004114092A
Application number: JP2002280807A
Authority: JP
Inventors: Tomokatsu Aizawa; 相澤　友勝; Yuji Yonenaga; 米永　裕司
Original assignee: Chuo Seisakusho KK; Japan Science and Technology Corp
Current assignee: Chuo Seisakusho KK; Japan Science and Technology Agency
Priority date: 2002-09-26
Filing date: 2002-09-26
Publication date: 2004-04-15
Anticipated expiration: 2022-09-26
Also published as: JP4024119B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic welding set using a semiconductor switch and a welding transformer, without causing damage or consumption of a contact and occurrence of noise. <P>SOLUTION: In the electromagnetic welding set for generating eddy current and electromagnetic force by applying magnetic flux generated by a magnetic flux generating coil to stacked metal sheets, and performing the seam welding of the metal sheets, a plurality of welding transformers 1 and 1 are provided, secondary windings 5 and 5 thereof connected in parallel and connected to a magnetic flux generating coil 6, and primary windings 2 and 2 of the welding transformers 1 and 1 are connected to capacitors 3 and 3 via semiconductor switches 4 and 4. A control device 8 of the semiconductor switches 4 and 4 to discharge charges accumulated in the capacitors 3 and 3 through the primary windings 2 and 2 of the welding transformers 1 and 1 by simultaneously closing the semiconductor switches 4 and 4 is provided. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、金属薄板を電磁力によって溶接する電磁溶接機であって、半導体スイッチおよび溶接トランスを使用した電磁溶接装置に関するものである。
【０００２】
【従来の技術】
【特許文献１】特開平１１−１９２５６２号公報
【０００３】
アルミニウムなどの金属薄板を容易にシーム溶接する方法として、本願発明者の１名が考えた特開平１１−１９２５６２のような電磁溶接法がある。この電磁溶接法は図９及び図１０に示すように、スイッチ９を介してコンデンサ１０に接続された一回巻の磁束発生コイル６の間に被溶接物７として２枚の金属薄板を重ねて置き、図示しないコンデンサ充電電源装置によりコンデンサ１０を充電した後スイッチ９を閉じて磁束発生コイル６にコンデンサ１０の放電電流を流して溶接するものである。すなわち、磁束発生コイル６にコンデンサ１０の放電電流が流れると発生する磁束は図１１に示すように金属薄板に鎖交し、金属薄板に渦電流が流れ同時に金属薄板の重ねた部分を押圧する電磁力が働いてシーム溶接されるものである。
【０００４】
この電磁溶接法では、例えば磁束発生コイル６を厚さ１０ｍｍ、幅５ｍｍのクロム銅製導体板により構成し、板厚０．５〜１ｍｍのアルミニウム薄板５を、長さ１００ｍｍに亘ってシーム溶接する場合には、必要な溶接電流の最大値が１５０〜２００ｋＡ、コンデンサ１０に蓄積すべきエネルギーは２〜４ｋＪとなる。このパルス大電流はスイッチ９を通して直接磁束発生コイル６に流すものであるが、このような大電流のスイッチングには半導体スイッチを使用することができず、放電ギャップスイッチが使用されていた。ところが放電ギャップスイッチには接点の損傷、消耗、電極周囲の絶縁物の劣化などがあって連続使用に制限があり、動作時に衝撃音等の騒音を発生するという問題があった。
【０００５】
こうした問題を解決するためには溶接トランスを使用することが考えられる。例えば、巻数比１０：１の溶接トランス２１を使用すれば、溶接トランス２１の一次巻線側では電流値が１／１０の１５〜２０ｋＡになる。電流値がこの程度に下がれば、図１２に示すようにコンデンサ２３及び半導体スイッチ２４を並列にして使用することが可能となる。また、卷数比をさらに大きくして一次巻線側の電流値を下げ、電圧を高くして図１３に示すようにコンデンサ２３及び半導体スイッチ２４を直列にして使用することも可能となる。溶接トランス２１の損失を無視すれば、磁束発生コイル６に流れる電流は１５０〜２００ｋＡのままであり、溶接トランス２１を使用しない図９の場合と同様シーム溶接が可能となる筈である。
【０００６】
溶接トランスを使用する場合、一次巻線と二次巻線との間の電磁結合が悪いと漏れ磁束が生じ、磁束発生コイル側への電磁エネルギー伝達時に損失が生じる。従来、一般のトランスでは鉄芯を使用して一次巻線と二次巻線との間の電磁結合を高めている。しかし、電磁溶接法では電流値が大きく、その時間的変化が速いため鉄芯が飽和し、鉄芯を使用することは不可能である。鉄芯に代わる高周波用の磁心も考えられるが、大電力用としては適当なものが存在しない。したがって、鉄芯、磁心なしで溶接トランスの一次巻線と二次巻線との間の電磁結合を高める必要があり、実際に溶接トランスを使用することは困難であった。
【０００７】
このようなことから、本願発明者の１名は溶接トランス一次巻線の内側に磁束発生用コイルとトランス２次巻線とを一体化させて配置する装置および溶接法を考え、特願２００１−１１８８６４として出願中である。この発明は、磁束発生用コイルとトランス２次巻線とを一体化させることで溶接トランスを別途設ける必要をなくし、漏れ磁束の問題を解決したものである。
【０００８】
ところが、溶接トランスの問題は解決されてもコンデンサ及び半導体スイッチは並列もしくは直列とする必要があり、コンデンサ及び半導体スイッチを並列にした場合には各並列枝路に電流を均等に分散させることが困難であるという問題があった。さらに、このコンデンサ及び半導体スイッチを並列にした場合、直列にした場合のいずれの場合にも、インダクタンスの大きい溶接トランスの一次巻線に全ての電流すなわち大きなエネルギーが集中することになり、電磁溶接ではこの集中した電流で生じる高密度磁束の時間的変化が速いため大きな電圧が誘起され、半導体スイッチの保護対策が容易でないという問題があった。
【０００９】
【発明が解決しようとする課題】
本発明は上記の問題点を解決し、放電ギャップスイッチに替えて半導体スイッチを使用し、接点の損傷、消耗、騒音の発生等のない半導体スイッチおよび溶接トランスを使用した電磁溶接装置を提供するためになされたものである。
【００１０】
【課題を解決するための手段】
上記の問題を解決するためになされた請求項１の発明は、高密度の磁束を発生する幅の狭い磁束発生コイルを備え、重ねて置いた金属薄板に磁束発生コイルの発生する磁束を加えることにより渦電流と電磁力を発生させ、その渦電流と電磁力を利用して金属薄板をシーム溶接する、半導体スイッチおよび溶接トランスを使用した電磁溶接装置であって、複数の溶接トランスを設けてその二次巻線を並列に接続したうえ磁束発生コイルに接続し、各溶接トランスの一次巻線はそれぞれ半導体スイッチを介してコンデンサに接続し、各半導体スイッチを同時に閉路して各コンデンサに蓄積された電荷を各溶接トランスの一次巻線を通して放電させる半導体スイッチの制御装置を設けたことを特徴とするものである。
【００１１】
同一の問題を解決するためになされた請求項２の発明は、高密度の磁束を発生する幅の狭い磁束発生コイルを備え、重ねて置いた金属薄板に磁束発生コイルの発生する磁束を加えることにより渦電流と電磁力を発生させ、その渦電流と電磁力を利用して金属薄板をシーム溶接する、半導体スイッチおよび溶接トランスを使用した電磁溶接装置であって、複数の一次巻線を備えた溶接トランスを設け、該溶接トランスの１個又は複数の二次巻線は前記複数の一次巻線に共通のものとして二次巻線の一部を磁束発生コイルとし、各一次巻線はそれぞれ半導体スイッチを介してコンデンサに接続し、各半導体スイッチを同時に閉路して各コンデンサに蓄積された電荷を各溶接トランスの一次巻線を通して放電させる半導体スイッチの制御装置を設けたことを特徴とするものである。
【００１２】
請求項２の発明においては、二次巻線を１個とし、該二次巻線の１つの面に幅の狭い磁束発生コイルを一体に設けたものとすることができ、あるいは、二次巻線を２個とし、該２個の二次巻線を巻線軸が平行になるように配置し、二次巻線の互いに相対する面に幅の狭い磁束発生コイルをそれぞれ一体に設けたものとすることができる。二次巻線を２個とし、該２個の二次巻線を巻線軸が平行になるように配置し、二次巻線の互いに相対する面に幅の狭い磁束発生コイルをそれぞれ一体に設けたものとした場合には、二次巻線の空間を導体で充填したものとすることができる。
【００１３】
【発明の実施の形態】
次に、本発明の電磁溶接機の実施形態について、図を参照しながら具体的に説明する。
図１は第１の実施の形態の回路構成を示すもので、複数の溶接トランス１、１、１の一次巻線２、２、２にコンデンサ３、３、３と半導体スイッチ４、４、４との直列回路がそれぞれ接続してある。複数の溶接トランス１、１、１の二次巻線５、５、５は並列に接続したうえ磁束を発生して溶接する１回巻の磁束発生コイル６に接続してある。溶接トランス１、１、１の数及び巻数比は、溶接条件から必要な電流を磁束発生コイル６に流すために必要な溶接トランスの一次巻線の電流が使用する半導体スイッチの定格以内になるように選んでおく。コンデンサ３、３、３にはそれぞれ図示しないコンデンサ充電装置が接続してあり、半導体スイッチ４、４、４を同時に閉路させる制御装置８が設けてある。
【００１４】
個々の溶接トランス１は具体的には一次巻線２と二次巻線５との間の漏れ磁束を減らすため、各巻線を厚さ０．５〜１ｍｍの平板状導体で構成し、絶縁シートを挟んで、０．２〜０．３ｍ^２というような比較的に大きな断面の周囲を重ね巻きすることが好ましい。また、巻数の多い一次巻線２の胴体幅を狭く、巻数の少ない二次巻線の導体幅を広くして一次巻線２の巻幅と二次巻線５巻幅を一致させることが好ましい。
【００１５】
このような構成の電磁溶接機の磁束発生コイル６の間に被溶接物７である重ね合わせた２枚の金属薄板を置き、コンデンサ３、３、３を充電したうえ制御装置８を動作させて半導体スイッチ４、４、４を閉路すれば、溶接トランス１、１、１の一次巻線２、２、２にコンデンサ３、３、３の放電電流が流れる。溶接トランス１、１、１の二次巻線５、５、５にはそれぞれ巻数比にしたがって電流が流れ、その加え合わされた電流が磁束発生コイル６に流れて被溶接物７が溶接されることになる。磁束発生コイル６の間に被溶接物７を置く際に磁束発生コイル６と被溶接物７との間に絶縁物を介挿して固定しておくことは従来の電磁溶接を行う場合と同様である。
【００１６】
板厚０．５〜１ｍｍのアルミニウム薄板を長さ１００ｍｍに亘ってシーム溶接するのに必要な溶接電流の最大値は、１５０〜２００ｋＡである。例えば溶接トランス１、１、１の巻数比を全て１０：１、数を３個とし、溶接トランス１、１、１の漏れ磁束を無視すれば、各一次巻線２、２、２に流れる電流は溶接電流の３０分の１の５〜７ｋＡとなり、半導体スイッチ４、４、４として市販されているサイリスタが並列接続することなく使用可能となる。また、溶接トランス１、１、１は１個あたりの容量を小さくすることができるので、製作することが可能になる。
【００１７】
図２は第２の実施の形態の回路構成を示すもので、複数の溶接トランス１、１と複数の溶接トランス１１、１１の２グループの溶接トランスを備えたものとしてある。各溶接トランス１、１及び１１、１１の一次巻線２、２及び１２、１２には第１の実施の形態のものと同様にコンデンサ３、３及び１３、１３と半導体スイッチ４、４及び１４、１４の直列回路がそれぞれ接続してある。溶接トランス１、１及び１１、１１の二次巻線５、５及び１５、１５はグループごとに並列に接続したうえ磁束発生コイル６と直列に接続してある。
【００１８】
このような構成の電磁溶接機の磁束発生コイル６の間に被溶接物７を置き、コンデンサ３、３及び１３、１３を充電したうえ半導体スイッチ４、４及び１４、１４を閉路すれば、溶接トランス１、１及び１１、１１の一次巻線２、２及び１２、１２にコンデンサ３、３及び１３、１３の放電電流が流れる。溶接トランス１、１及び１１、１１の二次巻線５、５及び１５、１５にはそれぞれ巻数比にしたがって電流が流れ、その加え合わされた電流が磁束発生コイル６に流れて被溶接物７が溶接されることになる。
【００１９】
この第２の実施の形態のものでは溶接トランス１、１及び１１、１１の二次巻線５、５及び１５、１５が直並列に接続されることになり、例えば溶接トランス１、１及び１１、１１の巻数比を全て１０：１、数をそれぞれ２個とすれば各一次巻線２、２及び１２、１２に流れる電流は溶接電流の１０分の１となる。溶接トランス１、１及び１１、１１の数を適正に定めることにより、第２の実施の形態のものでも半導体スイッチ４、４及び１４、１４として市販されているサイリスタが並列接続することなく使用可能となる。また、溶接トランス１、１及び１１、１１は１個あたりの容量を小さくすることができるので、製作することが可能になる。さらに、溶接トランス１、１及び１１、１１の巻数比を同じとすれば、第１の実施の形態のものに比べて半導体スイッチ４、４及び１４、１４が低耐圧のものでよいという利点がある。
【００２０】
図３及び図４は第３の実施の形態のものの溶接トランス１の構造を示すもので、溶接トランス１の矩形形状に複数回巻回した複数の一次巻線２、２の内側に矩形形状に一回巻回した二次巻線５を配置し、該二次巻線５の一部を磁束発生コイル６としてある。磁束発生コイル６とした二次巻線５の一部は幅を狭く、電流が集中するようにしたものである。図３では一次巻線２、２が二次巻線５の外側に置かれることになるが、これを二次巻線５の内側あるいは分割して両側に置くこともできる。図３及び図４では省略してあるが、各一次巻線２、２には第１の実施の形態のものと同様にコンデンサと半導体スイッチの直列回路がそれぞれ接続してある。この第３の実施の形態のものの回路構成は図１に示す第１の実施の形態のものと同じになるわけであるが、二次巻線５は共通であり、磁束発生コイル６は二次巻線５と一体になっている。
【００２１】
このような構成の電磁溶接装置の磁束発生コイル６に接して被溶接物７を置き、コンデンサを充電したうえ半導体スイッチを閉路すれば、溶接トランス１、１の一次巻線２、２にコンデンサ放電電流が流れる。二次巻線５及び磁束発生コイル６には巻数比にしたがった電流の総和の電流が流れ、被溶接物７が溶接されることになる。この第３の実施の形態のものは第１の実施の形態のものに比べて２次巻線５、５を別途並列に配線する必要がないので配線に無駄がなく、漏れ磁束が少なく、効率がよくなる利点がある。さらに一次巻線２、２の作る磁束の一部も被溶接物に直接に鎖交し、この磁束の向きは磁束発生コイル６に流れる電流の作る磁束と同じであり、効率を向上させることになる。
【００２２】
磁束発生コイルをこの第３の実施の形態のもののように構成した場合には、被溶接物７を一回巻の磁束発生コイル６の外側に置くことになる。この場合磁束発生コイル６が発生する磁束は図５に示すように金属薄板に鎖交し、金属薄板５の重ねた部分を押圧する電磁力が働く。同じ電流が流れた場合、鎖交する磁束密度、電磁力は、図９の場合に比べ小さくなるが、流す電流を増加させれば同様にシーム溶接される。重ねた金属薄板の両面に磁束発生コイル６を配置せずにシーム溶接したい場合のほか、１枚の金属薄板を管材などの側面にシーム溶接する場合に利用できる。
【００２３】
被溶接物７である金属薄板近くの磁束発生コイル６の導体幅は、電流を集中させてシーム溶接できるように狭くする必要があるが、磁束発生コイル６と一体とした二次巻線５の部分は磁束発生コイル６のように細くする必要はない。一体とした二次巻線５及び磁束発生コイル６には電磁力が働くので、この電磁力による変形を防ぐため、二次巻線５及び磁束発生コイル６を構成する導体の板厚を厚くし、さらに要すれば強固な絶縁材により補強することが好ましい。二次巻線５及び磁束発生コイル６を一次巻線２、２の内側に配置した場合には、二次巻線５及び磁束発生コイル６の板厚を厚くしても二次巻線５及び磁束発生コイル６に流れる電流が外側表皮部分に集中して流れる利点がある。
【００２４】
図６は第４の実施の形態のものの溶接トランス１の構造を示すもので、溶接トランス１の矩形形状に複数回巻回した複数の一次巻線２、２の内側に２個の矩形形状に一回巻回した二次巻線５、５が配置してある。この二次巻線５、５の互いに対向する面は幅を狭くして電流が集中するようにし、磁束発生コイル６、６としてある。各々の磁束発生コイル６を一体にした二次コイル５は第３の実施の形態のものと同じ構成になるものである。一次巻線２、２には第１の実施の形態のものと同様にコンデンサと半導体スイッチの直列回路がそれぞれ接続してある。
【００２５】
このような構成の電磁溶接装置の磁束発生コイル６、６の間に被溶接物７を置き、コンデンサを充電したうえ半導体スイッチを閉路すれば、溶接トランス１の一次巻線２、２にコンデンサの放電電流が流れる。二次巻線５、５及び磁束発生コイル６、６には巻数比にしたがって電流が流れ、被溶接物７がシーム溶接されることになる。この場合被溶接物７は磁束発生コイル６、６の間に置かれており、第１の実施の形態のものと同様にシーム溶接されるわけである。
【００２６】
図７及び図８は第５の実施の形態のものの溶接トランス１の構造を示すもので、溶接トランス１の矩形形状に複数回巻回した複数の一次巻線２、２の内側に２個の一回巻の二次巻線５、５を配置し、該二次巻線５、５の互いに対向する面を磁束発生コイル６、６としてある。この二次巻線５は台形形状の導体であって、一次巻線２、２からの誘導電流であるパルス状の溶接電流は、図７に点線で示すように周辺の表面に近い部分に流れ、幅の狭い磁束発生コイル６、６になる部分では電流が集中して流れることになる。一次巻線２、２には第１の実施の形態のものと同様にコンデンサと半導体スイッチの直列回路がそれぞれ接続してある。
【００２７】
このような構成の電磁溶接機の磁束発生コイル６、６の間に被溶接物７を置き、コンデンサを充電したうえ半導体スイッチを閉路すれば、溶接トランス１の一次巻線２、２にコンデンサの放電電流が流れる。二次巻線５、５及び磁束発生コイル６、６になる部分には巻数比にしたがって電流が流れ、被溶接物７がシーム溶接されることになる。このような二次巻線５、５を使用した場合には、溶接電流が内部にも少しは分布して流れるためエネルギー効率が多少悪くなるが、磁束発生コイルの耐久性を著しく向上させることができる利点がある。
【００２８】
【発明の効果】
以上説明した本発明によれば、複数の溶接トランスあるいは複数の一次巻線を備えた溶接トランスを使用するようにしたので個別の一次巻線に流れる電流は一次巻線の数に応じて小さくすることができ、スイッチとして半導体素子を使用することができる。これにより放電ギャップスイッチを使用する必要がなくなり、放電ギャップスイッチの使用にともなう接点の損傷、消耗、騒音の発生等の問題が解消される利点がある。したがって、従来の問題点を解決し実用性を増した半導体スイッチおよび溶接トランスを使用した電磁溶接装置を提供するものとして業界に寄与するところ極めて大である。
【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結線図である。
【図２】本発明の第２の実施の形態を示す結線図である。
【図３】本発明の第３の実施の形態の溶接トランスの構成を示す平面図である。
【図４】本発明の第３の実施の形態の溶接トランスの構成を示す正面図である。
【図５】第３の実施の形態のものの磁束の状態を示す図である。
【図６】本発明の第４の実施の形態の溶接トランスの構成を示す正面図である。
【図７】本発明の第５の実施の形態の溶接トランスの構成を示す正面図である。
【図８】本発明の第５の実施の形態の溶接トランスの構成を示す縦断側面図である。
【図９】電磁溶接法の原理を示す構成図である。
【図１０】磁束発生コイルと被溶接物の配置を示す図である。
【図１１】溶接部の電流と磁束を示す図である。
【図１２】従来の電磁溶接装置に溶接トランスを組み合わせた例を示す結線図である。
【図１３】従来の電磁溶接装置に溶接トランスを組み合わせた別の例を示す結線図である。
【符号の説明】
１　溶接トランス
２　一次巻線
３　コンデンサ
４　半導体スイッチ
５　二次巻線
６　磁束発生コイル
７　被溶接物
８　制御装置
１１　溶接トランス
１２　一次巻線
１３　コンデンサ
１４　半導体スイッチ
１５　二次巻線[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic welding machine for welding a thin metal plate by electromagnetic force, and more particularly to an electromagnetic welding device using a semiconductor switch and a welding transformer.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. 11-192562
As a method of easily seam-welding a thin metal plate such as aluminum, there is an electromagnetic welding method as disclosed in Japanese Patent Application Laid-Open No. H11-192562 considered by one of the present inventors. In this electromagnetic welding method, as shown in FIG. 9 and FIG. 10, two thin metal plates are stacked as a work 7 between a single-turn magnetic flux generating coil 6 connected to a capacitor 10 via a switch 9. After the capacitor 10 is charged by a capacitor charging power supply device (not shown), the switch 9 is closed and the discharge current of the capacitor 10 is supplied to the magnetic flux generating coil 6 for welding. That is, as shown in FIG. 11, the magnetic flux generated when the discharge current of the capacitor 10 flows through the magnetic flux generating coil 6 is linked to the thin metal plate, and the eddy current flows through the thin metal plate and simultaneously presses the overlapped portion of the thin metal plate. Seam welding is performed by force.
[0004]
In this electromagnetic welding method, for example, when the magnetic flux generating coil 6 is formed of a chromium copper conductor plate having a thickness of 10 mm and a width of 5 mm, and a thin aluminum plate 5 having a thickness of 0.5 to 1 mm is seam-welded over a length of 100 mm. In this case, the maximum value of the required welding current is 150 to 200 kA, and the energy to be stored in the capacitor 10 is 2 to 4 kJ. Although this large pulse current flows directly to the magnetic flux generating coil 6 through the switch 9, a semiconductor switch cannot be used for switching such a large current, and a discharge gap switch has been used. However, the discharge gap switch has problems such as damage to the contacts, wear and tear, deterioration of the insulator around the electrodes, and the like, so that continuous use is limited, and there is a problem that noise such as an impact sound is generated during operation.
[0005]
In order to solve these problems, it is conceivable to use a welding transformer. For example, if a welding transformer 21 having a turns ratio of 10: 1 is used, the current value on the primary winding side of the welding transformer 21 is 1/10, that is, 15 to 20 kA. If the current value decreases to this extent, the capacitor 23 and the semiconductor switch 24 can be used in parallel as shown in FIG. It is also possible to further increase the turns ratio to reduce the current value on the primary winding side and increase the voltage to use the capacitor 23 and the semiconductor switch 24 in series as shown in FIG. If the loss of the welding transformer 21 is neglected, the current flowing in the magnetic flux generating coil 6 remains at 150 to 200 kA, and seam welding should be possible as in the case of FIG.
[0006]
When a welding transformer is used, if the electromagnetic coupling between the primary winding and the secondary winding is poor, a leakage magnetic flux is generated, and a loss occurs when electromagnetic energy is transmitted to the magnetic flux generating coil side. Conventionally, a general transformer uses an iron core to enhance electromagnetic coupling between a primary winding and a secondary winding. However, in the electromagnetic welding method, the current value is large, and its time change is fast, so that the iron core is saturated, and it is impossible to use the iron core. A magnetic core for high frequency instead of an iron core is also conceivable, but there is no suitable one for high power. Therefore, it is necessary to enhance the electromagnetic coupling between the primary winding and the secondary winding of the welding transformer without the iron core and the magnetic core, and it has been difficult to actually use the welding transformer.
[0007]
In view of the above, one of the inventors of the present invention has considered a device and a welding method in which a magnetic flux generating coil and a transformer secondary winding are integrated and arranged inside a welding transformer primary winding, and a method disclosed in Japanese Patent Application No. 2001-214,197. Pending as 118864. The present invention solves the problem of leakage magnetic flux by integrating a magnetic flux generating coil and a secondary winding of a transformer, thereby eliminating the need for separately providing a welding transformer.
[0008]
However, even if the problem of the welding transformer is solved, the capacitor and the semiconductor switch need to be in parallel or in series, and when the capacitor and the semiconductor switch are in parallel, it is difficult to distribute the current evenly to each parallel branch. There was a problem that is. Further, in both cases where the capacitor and the semiconductor switch are arranged in parallel or in series, all current, that is, large energy is concentrated on the primary winding of the welding transformer having a large inductance. Since the temporal change of the high-density magnetic flux generated by the concentrated current is fast, a large voltage is induced, and there is a problem that protection measures for the semiconductor switch are not easy.
[0009]
[Problems to be solved by the invention]
The present invention has been made to solve the above problems, and to provide an electromagnetic welding apparatus using a semiconductor switch and a welding transformer that uses a semiconductor switch instead of a discharge gap switch and does not cause damage, wear, and noise of contacts. It was done in.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 includes a narrow magnetic flux generating coil for generating a high density magnetic flux, and applying a magnetic flux generated by the magnetic flux generating coil to a stacked metal thin plate. An electromagnetic welding apparatus using a semiconductor switch and a welding transformer, which generates an eddy current and an electromagnetic force by using the eddy current and the electromagnetic force to seam-weld a thin metal sheet, using a plurality of welding transformers. The secondary winding was connected in parallel and connected to the magnetic flux generating coil.The primary winding of each welding transformer was connected to a capacitor via a semiconductor switch, and each semiconductor switch was closed simultaneously and stored in each capacitor. A control device for a semiconductor switch for discharging an electric charge through a primary winding of each welding transformer is provided.
[0011]
In order to solve the same problem, a second aspect of the present invention includes a magnetic flux generating coil having a narrow width for generating a high-density magnetic flux, and applying a magnetic flux generated by the magnetic flux generating coil to a stacked metal thin plate. An electromagnetic welding apparatus using a semiconductor switch and a welding transformer, which generates an eddy current and an electromagnetic force by using the eddy current and the electromagnetic force to seam-weld a thin metal plate, and includes a plurality of primary windings. A welding transformer is provided, one or more secondary windings of the welding transformer are common to the plurality of primary windings, and a part of the secondary windings is a magnetic flux generating coil, and each primary winding is a semiconductor. A control device for a semiconductor switch connected to a capacitor via a switch and simultaneously closing each semiconductor switch and discharging the electric charge accumulated in each capacitor through the primary winding of each welding transformer is provided. It is characterized in.
[0012]
According to the second aspect of the present invention, the secondary winding may be one, and the magnetic flux generating coil having a small width may be integrally provided on one surface of the secondary winding. A wire having two wires, the two secondary windings being arranged so that the winding axes are parallel to each other, and a narrow magnetic flux generating coil provided integrally on the mutually facing surfaces of the secondary windings; can do. Two secondary windings are provided, and the two secondary windings are arranged so that the winding axes are parallel to each other. Narrow magnetic flux generating coils are provided integrally on surfaces of the secondary windings facing each other. In this case, the space of the secondary winding can be filled with a conductor.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the electromagnetic welding machine of the present invention will be specifically described with reference to the drawings.
FIG. 1 shows a circuit configuration of the first embodiment, in which a plurality of welding transformers 1, 1, 1 have primary windings 2, 2, 2 with capacitors 3, 3, 3 and semiconductor switches 4, 4, 4, respectively. Are connected to each other. The secondary windings 5, 5, 5 of the plurality of welding transformers 1, 1, 1 are connected in parallel and connected to a single-turn magnetic flux generating coil 6 which generates and welds a magnetic flux. The number and turns ratio of the welding transformers 1, 1, 1 are set so that the current of the primary winding of the welding transformer required for flowing the necessary current to the magnetic flux generating coil 6 from the welding conditions is within the rating of the semiconductor switch used. To choose. A capacitor charging device (not shown) is connected to each of the capacitors 3, 3, and 3, and a control device 8 for simultaneously closing the semiconductor switches 4, 4, and 4 is provided.
[0014]
In order to reduce the leakage magnetic flux between the primary winding 2 and the secondary winding 5, each of the welding transformers 1 is formed of a flat conductor having a thickness of 0.5 to 1 mm. , It is preferable to overlap and wind around a relatively large cross section such as 0.2 to 0.3 m ² . Further, it is preferable that the body width of the primary winding 2 having a large number of turns is narrow, and the conductor width of the secondary winding having a small number of turns is widened so that the winding width of the primary winding 2 and the winding width of the secondary winding 5 are matched. .
[0015]
The superposed two thin metal plates as the workpiece 7 are placed between the magnetic flux generating coils 6 of the electromagnetic welding machine having such a configuration, and the capacitors 3, 3, and 3 are charged, and the control device 8 is operated. When the semiconductor switches 4, 4, 4 are closed, the discharge current of the capacitors 3, 3, 3 flows through the primary windings 2, 2, 2 of the welding transformers 1, 1, 1. A current flows through the secondary windings 5, 5, 5 of the welding transformers 1, 1, 1 in accordance with the turns ratio, and the added current flows to the magnetic flux generating coil 6 to weld the work 7 to be welded. become. When placing the workpiece 7 between the magnetic flux generating coils 6, inserting an insulator between the magnetic flux generating coil 6 and the workpiece 7 and fixing the same is similar to the case of performing conventional electromagnetic welding. is there.
[0016]
The maximum value of the welding current required for seam welding a thin aluminum plate having a thickness of 0.5 to 1 mm over a length of 100 mm is 150 to 200 kA. For example, if the turns ratio of the welding transformers 1, 1, 1 is all 10: 1 and the number is 3, and the leakage flux of the welding transformers 1, 1, 1 is ignored, the current flowing through each primary winding 2, 2, 2 Is 5/30 kA, which is 1/30 of the welding current, and thyristors commercially available as semiconductor switches 4, 4 and 4 can be used without being connected in parallel. In addition, since the capacity of each of the welding transformers 1, 1, 1 can be reduced, it is possible to manufacture them.
[0017]
FIG. 2 shows a circuit configuration of the second embodiment, which is provided with two groups of welding transformers, a plurality of welding transformers 1 and 1 and a plurality of welding transformers 11 and 11. The primary windings 2, 2, 12, and 12 of the respective welding transformers 1, 1, 11, 11, 11 have capacitors 3, 3, 13, 13, 13 and semiconductor switches 4, 4, and 14 as in the first embodiment. , 14 are connected to each other. The secondary windings 5, 5, 15, 15 of the welding transformers 1, 1, 11, 11, 11 are connected in parallel for each group and connected in series with the magnetic flux generating coil 6.
[0018]
If the workpiece 7 is placed between the magnetic flux generating coils 6 of the electromagnetic welding machine having such a configuration, the capacitors 3, 3, 13 and 13 are charged and the semiconductor switches 4, 4 and 14 and 14 are closed, welding is performed. Discharge currents of the capacitors 3, 3, 13 and 13 flow through the primary windings 2, 2, 12 and 12 of the transformers 1, 1 and 11, 11. A current flows through the secondary windings 5, 5, 15, 15 and 15 of the welding transformers 1, 1, 11, and 11, respectively, in accordance with the turns ratio, and the added current flows through the magnetic flux generating coil 6 to cause the workpiece 7 to be welded. Will be welded.
[0019]
In the second embodiment, the secondary windings 5, 5, 15, and 15 of the welding transformers 1, 1, 11, and 11 are connected in series and parallel. , 11 are all 10: 1 and the number is two, the current flowing through each of the primary windings 2, 2, 12, and 12 is 1/10 of the welding current. By properly setting the number of the welding transformers 1, 1, 11, and 11, thyristors commercially available as the semiconductor switches 4, 4, and 14, and 14 can be used in the second embodiment without being connected in parallel. It becomes. In addition, since the capacity of each of the welding transformers 1, 1, 11, and 11 can be reduced, it is possible to manufacture them. Furthermore, assuming that the turns ratio of the welding transformers 1, 1, 11, and 11 is the same, there is an advantage that the semiconductor switches 4, 4, and 14 and 14 need to have a low withstand voltage as compared with the first embodiment. is there.
[0020]
FIGS. 3 and 4 show the structure of a welding transformer 1 according to the third embodiment. The welding transformer 1 has a rectangular shape inside a plurality of primary windings 2 and 2 wound a plurality of times in a rectangular shape. A secondary winding 5 wound once is arranged, and a part of the secondary winding 5 is used as a magnetic flux generating coil 6. A part of the secondary winding 5 serving as the magnetic flux generating coil 6 has a narrow width so that current is concentrated. In FIG. 3, the primary windings 2, 2 are placed outside the secondary winding 5, but they can also be placed inside the secondary winding 5 or divided and placed on both sides. Although omitted in FIG. 3 and FIG. 4, a series circuit of a capacitor and a semiconductor switch is connected to each of the primary windings 2 and 2 as in the first embodiment. The circuit configuration of the third embodiment is the same as that of the first embodiment shown in FIG. 1, but the secondary winding 5 is common and the magnetic flux generating coil 6 is It is integrated with the winding 5.
[0021]
When the workpiece 7 is placed in contact with the magnetic flux generating coil 6 of the electromagnetic welding apparatus having such a configuration, the capacitor is charged and the semiconductor switch is closed, the capacitor is discharged to the primary windings 2 and 2 of the welding transformers 1 and 1. Electric current flows. The current of the total sum of the currents according to the turns ratio flows through the secondary winding 5 and the magnetic flux generating coil 6, and the workpiece 7 is welded. Compared to the first embodiment, the third embodiment eliminates the need to separately wire the secondary windings 5, 5 in parallel, so that there is no waste in wiring, less leakage magnetic flux, and efficiency. Has the advantage of being better. Further, a part of the magnetic flux generated by the primary windings 2 and 2 also directly interlinks with the workpiece, and the direction of the magnetic flux is the same as the magnetic flux generated by the current flowing through the magnetic flux generating coil 6. Become.
[0022]
When the magnetic flux generating coil is configured as in the third embodiment, the workpiece 7 is placed outside the single-turn magnetic flux generating coil 6. In this case, the magnetic flux generated by the magnetic flux generating coil 6 is linked to the thin metal plate as shown in FIG. 5, and an electromagnetic force for pressing the overlapping portion of the thin metal plate 5 works. When the same current flows, the interlinked magnetic flux density and electromagnetic force are smaller than those in FIG. 9, but if the flowing current is increased, seam welding is performed similarly. It can be used not only when seam welding is desired without disposing the magnetic flux generating coils 6 on both sides of the stacked metal thin plates, but also when seam welding a single metal thin plate to the side surface of a tube or the like.
[0023]
The conductor width of the magnetic flux generating coil 6 near the metal plate to be welded 7 needs to be narrow so that current can be concentrated and seam welding can be performed. The portion does not need to be as thin as the magnetic flux generating coil 6. Since electromagnetic force acts on the integrated secondary winding 5 and magnetic flux generating coil 6, the thickness of the conductors constituting the secondary winding 5 and magnetic flux generating coil 6 is increased to prevent deformation due to the electromagnetic force. If necessary, it is preferable to reinforce with a strong insulating material. When the secondary winding 5 and the magnetic flux generating coil 6 are arranged inside the primary windings 2 and 2, the secondary winding 5 and There is an advantage that the current flowing through the magnetic flux generating coil 6 flows intensively on the outer skin portion.
[0024]
FIG. 6 shows the structure of the welding transformer 1 according to the fourth embodiment. The welding transformer 1 is formed into two rectangular shapes inside a plurality of primary windings 2 and 2 wound a plurality of times in a rectangular shape. Secondary windings 5 and 5 wound once are arranged. The surfaces of the secondary windings 5 and 5 facing each other are narrowed so that current is concentrated, and are used as magnetic flux generating coils 6 and 6. The secondary coil 5 in which the respective magnetic flux generating coils 6 are integrated has the same configuration as that of the third embodiment. As in the first embodiment, a series circuit of a capacitor and a semiconductor switch is connected to the primary windings 2 and 2, respectively.
[0025]
When the workpiece 7 is placed between the magnetic flux generating coils 6 of the electromagnetic welding apparatus having such a configuration and the capacitor is charged and the semiconductor switch is closed, the capacitor of the capacitor is connected to the primary windings 2 and 2 of the welding transformer 1. A discharge current flows. An electric current flows through the secondary windings 5 and 5 and the magnetic flux generating coils 6 and 6 according to the turn ratio, and the workpiece 7 is seam-welded. In this case, the workpiece 7 is placed between the magnetic flux generating coils 6, 6 and is seam-welded in the same manner as in the first embodiment.
[0026]
FIGS. 7 and 8 show the structure of a welding transformer 1 according to the fifth embodiment, in which a plurality of primary windings 2, 2 wound in a rectangular shape of the welding transformer 1 a plurality of times, are provided inside. One-turn secondary windings 5 are arranged, and the surfaces of the secondary windings 5 facing each other are magnetic flux generating coils 6. The secondary winding 5 is a trapezoidal conductor, and a pulsed welding current, which is an induction current from the primary windings 2 and 2, flows to a portion near the peripheral surface as shown by a dotted line in FIG. In the portion where the magnetic flux generating coils 6 become narrow, the current flows intensively. As in the first embodiment, a series circuit of a capacitor and a semiconductor switch is connected to the primary windings 2 and 2, respectively.
[0027]
When the workpiece 7 is placed between the magnetic flux generating coils 6 of the electromagnetic welding machine having such a configuration, the capacitor is charged and the semiconductor switch is closed, the capacitor of the capacitor is connected to the primary windings 2 and 2 of the welding transformer 1. A discharge current flows. A current flows through the portions that become the secondary windings 5 and 5 and the magnetic flux generating coils 6 and 6 according to the turn ratio, and the workpiece 7 is seam-welded. When such secondary windings 5 and 5 are used, the welding current flows a little in the inside, so that the energy efficiency slightly deteriorates. However, the durability of the magnetic flux generating coil can be significantly improved. There are advantages that can be done.
[0028]
【The invention's effect】
According to the present invention described above, since a plurality of welding transformers or a welding transformer having a plurality of primary windings is used, the current flowing through each individual primary winding is reduced according to the number of primary windings. And a semiconductor element can be used as a switch. This eliminates the need to use a discharge gap switch, and has the advantage of eliminating problems such as damage to contacts, wear, and noise caused by the use of the discharge gap switch. Accordingly, it is extremely important to provide an electromagnetic welding apparatus using a semiconductor switch and a welding transformer which solves the conventional problems and has increased practicality, and which contributes to the industry.
[Brief description of the drawings]
FIG. 1 is a connection diagram showing a first embodiment of the present invention.
FIG. 2 is a connection diagram showing a second embodiment of the present invention.
FIG. 3 is a plan view showing a configuration of a welding transformer according to a third embodiment of the present invention.
FIG. 4 is a front view illustrating a configuration of a welding transformer according to a third embodiment of the present invention.
FIG. 5 is a diagram showing a state of a magnetic flux of the third embodiment.
FIG. 6 is a front view illustrating a configuration of a welding transformer according to a fourth embodiment of the present invention.
FIG. 7 is a front view showing a configuration of a welding transformer according to a fifth embodiment of the present invention.
FIG. 8 is a vertical sectional side view showing a configuration of a welding transformer according to a fifth embodiment of the present invention.
FIG. 9 is a configuration diagram showing the principle of the electromagnetic welding method.
FIG. 10 is a diagram showing an arrangement of a magnetic flux generating coil and a workpiece.
FIG. 11 is a diagram showing a current and a magnetic flux of a welding portion.
FIG. 12 is a connection diagram showing an example in which a welding transformer is combined with a conventional electromagnetic welding device.
FIG. 13 is a connection diagram showing another example in which a welding transformer is combined with a conventional electromagnetic welding apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Welding transformer 2 Primary winding 3 Capacitor 4 Semiconductor switch 5 Secondary winding 6 Magnetic flux generating coil 7 Workpiece 8 Control device 11 Welding transformer 12 Primary winding 13 Capacitor 14 Semiconductor switch 15 Secondary winding

Claims

Equipped with a narrow magnetic flux generating coil that generates a high-density magnetic flux, an eddy current and an electromagnetic force are generated by applying a magnetic flux generated by the magnetic flux generating coil to a stacked metal thin plate, and the eddy current and the electromagnetic force are reduced. An electromagnetic welding apparatus using a semiconductor switch and a welding transformer for seam welding a thin metal plate by using a plurality of welding transformers, connecting their secondary windings in parallel and connecting to a magnetic flux generating coil, The primary winding of each welding transformer is connected to a capacitor via a semiconductor switch, and the semiconductor switch is closed at the same time to discharge the electric charge accumulated in each capacitor through the primary winding of each welding transformer. An electromagnetic welding apparatus using a semiconductor switch and a welding transformer, characterized by comprising:

Equipped with a narrow magnetic flux generating coil that generates a high-density magnetic flux, an eddy current and an electromagnetic force are generated by applying a magnetic flux generated by the magnetic flux generating coil to a stacked metal thin plate, and the eddy current and the electromagnetic force are reduced. An electromagnetic welding apparatus using a semiconductor switch and a welding transformer for seam-welding a metal sheet using the same, comprising a welding transformer having a plurality of primary windings, and one or more secondary windings of the welding transformer. The wires are common to the plurality of primary windings, a part of the secondary winding is a magnetic flux generating coil, each primary winding is connected to a capacitor via a semiconductor switch, and each semiconductor switch is closed simultaneously. The semiconductor switch and the welding transformer are provided with a semiconductor switch control device for discharging the electric charge accumulated in each capacitor through the primary winding of each welding transformer. Use the electromagnetic welding apparatus.

3. The electromagnetic using a semiconductor switch and a welding transformer according to claim 2, wherein the secondary winding is one, and a narrow magnetic flux generating coil is integrally provided on one surface of the secondary winding. Welding equipment.

Two secondary windings are provided, and the two secondary windings are arranged so that the winding axes are parallel to each other. Narrow magnetic flux generating coils are provided integrally on surfaces of the secondary windings facing each other. An electromagnetic welding apparatus using the semiconductor switch and the welding transformer according to claim 2.

The electromagnetic welding apparatus using a semiconductor switch and a welding transformer according to claim 4, wherein the space of the secondary winding is filled with a conductor.