JP3701704B2

JP3701704B2 - AC / DC dual-purpose arc machining system

Info

Publication number: JP3701704B2
Application number: JP33402994A
Authority: JP
Inventors: 喜久夫寺山; 英治西山
Original assignee: Daihen Corp
Current assignee: Daihen Corp
Priority date: 1994-12-15
Filing date: 1994-12-15
Publication date: 2005-10-05
Anticipated expiration: 2020-10-05
Also published as: JPH08168882A

Description

【０００１】
【産業上の利用分野】
本発明は、交直両用のアーク溶接、切断またはアーク加熱等に使われるアーク加工装置において、アーク起動性能を改良した装置を提案したものである。
【０００２】
【従来の技術】
図１は、従来のアーク溶接装置の例である。図１において、１ないし３は１次入力線、５は電極側ケーブル、６は電極、７は被溶接物、８は被溶接物側ケーブル、ＴＳ１は起動スイッチである。溶接電源４において、１１は第１の直流電源、１５は第２の直流電源であり直流高電圧を発生する回路である。１６はダイオードであり第２の直流電源が発生する直流高電圧に耐えかつ溶接電流を流す容量のものが用いられる。１８はアーク発生検出手段であり通常アーク電流が流れているかいないかによってアーク発生と判断する。１９はスイッチ手段であり起動スイッチＴＳ１からの起動信号を受けて、図示を省略されたガス供給回路に指令を出し、電極の周囲にシールドガスの供給を開始させ、シールドガスが電極周囲に達する頃を見計らって第１の直流電源１１および第２の直流電源１５を動作させる。第２の直流電源１５が発生する直流高電圧はダイオード１６に阻止されて第１の直流電源１１には印加されず、電極６と被溶接物７間にのみ印加され、この間の絶縁を破って火花放電を発生させる。この火花放電に第１の直流電源から電力が供給されて火花放電は溶接アークに成長する。
【０００３】
【発明が解決しようとする課題】
図１の従来装置の場合は、直流出力のものに対してのみ適用できるものであり、その出力極性は固定されている。それ故、アーク加工部には装置によって定まった極性の出力が供給されるだけであり、被加工物の材質や加工方法に応じて被加工物側が正となる正極性アーク、電極側が正となる逆極性アークあるいは正・逆両極性のアークを所定の割合で切り替えて交流出力を得るなどの交直両用には適用できないものであった。
【０００４】
【課題を解決するための手段】
本発明は、直流電源の出力を正および逆の極性に切り替えてアーク加工負荷に供給する主スイッチング回路と、アーク加工負荷にアーク起動用の高電圧を供給するための直流高電圧発生回路と、直流電源と負荷出力端子との間に直列にされて直流高電圧発生回路と同極性のダイオードと、直流高電圧発生回路の出力極性と逆の極性の出力を通過させる副スイッチング回路と、アーク起動に際して直流高電圧発生回路を起動するとともに主スイッチング回路を直流高電圧発生回路の出力と同極性の出力をアーク加工負荷に供給するように駆動し、アーク起動後は高電圧直流発生回路の出力を遮断するとともに副スイッチング回路を導通させ、かつ所定の順序で主スイッチング回路をON-OFF制御する制御回路とを備えた構造とすることによって上記従来装置の問題点を解決したものである。
【０００５】
【実施例】
以下、本発明を図示の実施例によって説明する。図２は、本発明を交直両用のアーク溶接に適用したときの実施例を示す接続図であり、請求項１、２および６の実施例に相当する。図２において、１ないし３は１次入力線、５は電極側ケーブル、６は電極、７は被溶接物、８は被溶接物側ケーブル、ＴＳ１は起動スイッチ、ＲＶ１は出力電流調整器である。溶接電源９において、ＤＲ１は１次整流器、Ｃ１は平滑コンデンサ、ＴＲ１はインバータ回路、Ｔ１はインバータトランス、Ｌ１（１／２）、Ｌ１（２／２）はリアクトルであり、両リアクトルは共通の鉄心に巻かれたコイルからなり、各コイルは図中に・印で示すように直列に接続されたスイッチング素子ＴＲ２およびＴＲ３の導通によってそれぞれに流れる電流によって共有する鉄心に同方向の磁束を発生する極性に定められている。ＴＲ２およびＴＲ３は主スイッチング回路を構成するトランジスタ、ＣＴ１は電流検出器、Ｔｍ１は被溶接物側出力端子、Ｔｍ２は電極側出力端子である。なお、通常はトランジスタＴＲ２とトランジスタＴＲ３には逆並列にダイオードが接続されるが、図が繁雑になることをさけるために、それらのダイオードは図示を省略している。
【０００６】
また、図２において、ＤＲ３はダイオード、Ｓ１は副スイッチング回路を構成する電磁接触器、ＨＤは直流高電圧発生回路、ＣＬ２は制御回路である。なお、直流高電圧発生回路ＨＤは無負荷電圧は高いが出力インピーダンスは大きく、電極６と被溶接物７との間には火花放電が発生する程度にその出力電流は制限されている。
【０００７】
図２において、１次入力線１ないし３から３相の商用周波交流が加えられ、１次整流器ＤＲ１はこれを整流して直流にする。その出力は平滑コンデンサＣ１により平滑される。インバータ回路ＴＲ１は平滑コンデンサＣ１によって平滑された出力を商用周波数より高い周波数の交番電圧に変換してインバータトランスＴ１の１次巻線に供給する。インバータトランスＴ１は２次巻線に溶接に適した電圧が得られるようにその巻数比が選ばれる。２次整流回路ＤＲ２はインバータトランスＴ１の出力電圧を整流する。トランジスタＴＲ２とトランジスタＴＲ３はいずれか一方がＯＮで他方がＯＦＦとなって溶接出力の極性を切り替える。いまトランジスタＴＲ２がＯＮでトランジスタＴＲ３がＯＦＦとすると、溶接電流は、２次整流回路ＤＲ２の正出力端子、リアクトルＬ１（１／２）、トランジスタＴＲ２、ダイオードＤＲ３、被溶接物側出力端子Ｔｍ２、被溶接物側ケーブル８、被溶接物７、電極６、電極側ケーブル５、電極物側出力端子Ｔｍ１、電流検出器ＣＴ１の経路を流れ、被溶接物７と電極６の間に正極性のアークを発生させる。出力電流検出器ＣＴ１はアーク電流を検出して、検出信号を制御回路ＣＬ２に送る。制御回路ＣＬ２は出力調整器ＲＶ１からの出力電流指令信号と出力電流検出器ＣＴ１の検出信号とを比較し、その差が減ずるような指令信号をインバータ回路ＴＲ１に送る。この結果、溶接電源４の出力電流は出力調整器ＲＶ１の設定値に保たれる。
【０００８】
つぎに、トランジスタＴＲ２がＯＦＦにトランジスタＴＲ３がＯＮになると、トランジスタＴＲ２を通してリアクトルＬ１（１／２）に流れる電流とトランジスタＴＲ３を通してリアクトルＬ１（２／２）に流れる電流は鉄心を同じ方向に磁化するので、リアクトルＬ１（１／２）に流れていた電流はリアクトルＬ１（２／２）に移って流れることになる。その結果、溶接電流は２次整流回路ＤＲ２の零出力端子、出力電流検出器ＣＴ１、電極側出力端子Ｔｍ１、電極側ケーブル５、電極６、被溶接物７、被溶接物側ケーブル８、電磁接触器Ｓ１、トランジスタＴＲ３、リアクトルＬ１（２／２）、２次整流回路ＤＲ２の負出力端子の経路を流れ、電極６と被溶接物７の間に逆極性のアークを発生させる。トランジスタＴＲ２がＯＮでトランジスタＴＲ３がＯＦＦの状態と、トランジスタＴＲ２がＯＦＦでトランジスタＴＲ３がＯＮの状態とを交互に繰り返すことよって電極６と被溶接物７間に交流アークが得られる。
【０００９】
つぎにアーク起動時の動作について説明する。図２において、起動スイッチＴＳ１が押されると制御回路ＣＬ２は、図示を省略したガス供給回路に指令を出し、電極の周囲にシールドガスの供給を開始させる。シールドガスが電極周囲に達する頃を見計らって制御回路ＣＬ２は、インバータ回路ＴＲ１に動作の開始を、トランジスタＴＲ２にＯＮを、電磁接触器Ｓ１にＯＦＦを指令し、直流高電圧発生回路ＨＤには出力の開始を指令する。直流高電圧発生回路ＨＤの電圧はダイオードＤＲ３および開放状態の電磁接触器Ｓ１に阻止されてトランジスタＴＲ２およびトランジスタＴＲ３側にはかからず、電極６と被溶接物７間にかかり、この間の絶縁を破って火花放電を発生させる。この火花放電は、直流高電圧発生回路ＨＤの内部インピーダンスが高いために出力電流が小さいが、２次整流回路ＤＲ２からリアクトルＬ１（１／２）、トランジスタＴＲ２、ダイオードＤＲ３を経て同極性の電流が重畳して流れるので、火花放電電流は急速に増大して溶接アークに成長する。出力電流検出器ＣＴ１は溶接電流検出信号を制御回路ＣＬ２に送り、この検出信号によって制御回路ＣＬ２は直流高電圧発生回路ＨＤに動作の停止を指令し、直流アーク溶接を行う場合はトランジスタＴＲ２をＯＮ、トランジスタＴＲ３をＯＦＦ、電磁接触器Ｓ１をＯＦＦのままとし、交流アーク溶接を行う場合は電磁接触器Ｓ１をＯＮとした後、トランジスタＴＲ２とトランジスタＴＲ３を交互にＯＮ、ＯＦＦさせる。なお、電磁接触器Ｓ１はダイオードＤＲ３とは逆向きの電流を流すサイリスタなどの半導体スイッチング素子を用いてもよい。
【００１０】
ここで、交流出力時には、リアクトルＬ１（１／２）とリアクトルＬ１（２／２）との巻線を前述のように各コイルに流れる電流によって共有する鉄心に同じ方向の磁束が発生するようにその巻き方向を決定しておくと、極性の反転に際してトランジスタＴＲ２がＯＮからＯＦＦになるときにリアクトルＬ１（１／２）に流れていた電流がそのままリアクトルＬ１（２／２）に移って流れようとする。このためにトランジスタＴＲ２のＯＦＦと同時に高いサージ電圧が発生し、アークの再生を助ける。さらに、トランジスタＴＲ２とＴＲ３とを導通期間が極く短時間の重なりをもって交互にＯＮ−ＯＦＦするようにして両トランジスタを実質的に間隙なく制御するとよい。このようにするときは、トランジスタＴＲ２とトランジスタＴＲ３との重なり時間の間は、アークは消滅するが電流はリアクトルを通じてトランジスタＴＲ２とトランジスタＴＲ３とによって短絡されて流れ続け、その値はリアクトルによって抑制される。この状態でトランジスタＴＲ２がＯＦＦするとその直前にリアクトルに流れていた電流を維持するように高いサージ電圧がトランジスタＴＲ３の順方向に発生する。このサージ電圧は電極６と比溶接物７との間に先とは逆の極性で印加され、かつトランジスタＴＲ３がすでに導通状態にあるので、トランジスタＴＲ２がＯＦＦとなる瞬間に電極６と被溶接物７との間に発生することになりアークの再生がより確実となる。
【００１１】
なお、ＴＩＧアーク溶接においては、上記のように正極性からアーク起動を行うとアークの確立が不安定になることがある。このような場合には、直流高電圧発生回路ＨＤおよびダイオードＤＲ３の極性を図と逆にして、起動時にはトランジスタＴＲ３をＯＮとし、トランジスタＴＲ２をＯＦＦとして、逆極性から起動し、アークが確立したことを検出してから所望の極性になるようにトランジスタＴＲ２またはトランジスタＴＲ３をＯＮあるいはＯＦＦし、これにあわせて電磁接触器Ｓ１を開閉すればよい。
【００１２】
図３は、本発明をアーク溶接に適用したときの別の実施例であり、請求項１、３および７の発明の実施例に相当する。同図において、１０は溶接電源であり、図２に示した実施例と異なり、直流高電圧発生回路ＨＤを出力回路に直列接続してある。直流高電圧発生回路ＨＤの正側出力は被溶接物側出力端子Ｔｍ２、被溶接物側ケーブル８を経て被溶接物７に、また負側出力はトランジスタＴＲ２、リアクトルＬ１（１／２）、２次整流回路ＤＲ２および電極側出力端子Ｔｍ１、電極側ケーブル５を経て電極６にそれぞれ供給される。この直流高電圧によって電極６と被溶接物７間に火花放電が発生した後は図２に示した実施例の動作と同様である。なお、図２および図３の各実施例において、リアクトルＬ１（１／２）とトランジスタＴＲ２との順序およびリアクトルＬ１（２／２）とトランジスタＴＲ３との順序はそれぞれ図示と逆でもよい。
【００１３】
図４は本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、４および８の発明の実施例に相当する。同図においては、説明の煩雑を避けるために図１ない図３と同じ部分は省略し、これらと異なるインバータトランスＴ１以降のみを示す。
【００１４】
図４において、ＤＲ２ａないしＤＲ２ｄは２次整流回路ＤＲ２の各要素を構成するダイオード、ＤＲ３はダイオード、ＤＲ４およびＤＲ５はダイオード、Ｓ１は副スイッチング回路を構成する電磁接触器である。
【００１５】
図４において、アーク起動時はトランジスタＴＲ２をＯＮ、トランジスタＴＲ３をＯＦＦ、電磁接触器Ｓ１をＯＦＦとして直流高電圧発生回路ＨＤを動作させる。直流高電圧発生回路ＨＤの出力電圧は正側は被溶接物側出力端子Ｔｍ２、被溶接物側ケーブル８を経て被溶接物側７に、また負側は電極側出力端子Ｔｍ１、電極側ケーブル５を経て電極６に加わり被溶接物７と電極６との間に火花放電を発生させ、この火花放電にダイオードＤＲ２ａおよびＤＲ２ｂからリアクトルＬ１（１／２）、ダイオードＤＲ３、トランジスタＴＲ２を経て電流が流れ火花放電は溶接アークに成長する。ダイオードＤＲ３はダイオードＤＲ２ａおよびダイオードＤＲ２ｂおよびＯＮ状態のトランジスタＴＲ２に直流高電圧発生回路ＨＤの直流高電圧がかからないように阻止し、電磁接触器Ｓ１はダイオードＤＲ５およびＯＦＦ状態にあるトランジスタＴＲ３に直流高電圧発生回路ＨＤの直流高電圧がかからないように阻止するとともに、交流溶接時にはＯＮとなってトランジスタＴＲ３に電流を流す。なお、リアクトルＬ１（１／２）、ダイオードＤＲ３、トランジスタＴＲ２とダイオードＤＲ４との並列回路の接続の順序、リアクトルＬ１（２／２）、電磁接触器Ｓ１、トランジスタＴＲ３とダイオードＤＲ５との並列回路の接続の順序は図示の通りでなくてもよい。
【００１６】
図５は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、５および９の発明の実施例に相当する。同図においても図４と同様にインバータトランスＴ１以降のみ示してある。
図５において、直流高電圧発生回路ＨＤをダイオードＤＲ３に並列に接続してリアクトルＬ１（１／２）とトランジスタＴＲ２との間に直列に接続し、副スイッチング回路である電磁接触器Ｓ１はリアクトルＬ１（２／２）とトランジスタＴＲ３との間に直列に接続されている。直流高電圧発生回路ＨＤの正側の電圧はトランジスタＴＲ２および被溶接物側出力端子Ｔｍ２、被溶接物側ケーブル８を経て被溶接物７に、また、負側の電圧はリアクトルＬ１（１／２）、ダイオードＤＲ２ａまたはダイオードＤＲ２ｂ、インバータトランスＴ１および被溶接物側出力端子Ｔｍ１、電極側ケーブル５を経て電極６に印加される。なお、トランジスタＴＲ３とダイオードＤＲ５の並列回路に直流高電圧発生回路ＨＤの直流高電圧に耐えるトランジスタとダイオードを用いるときは電磁接触器Ｓ１を省略してもよい。図５においても、リアクトルＬ１（１／２）とダイオードＤＲ３およびトランジスタＴＲ２とダイオードＤＲ４との並列回路の順序およびリアクトルＬ（２／２）と電磁接触器Ｓ１とトランジスタＴＲ３とダイオードＤＲ５との並列回路の順序は図示の通りでなくてもよい。
【００１７】
図６は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１および１０の発明の実施例に相当する。図６においても図４に示した実施例と同様にインバータランスＴ１以降のみを示してあり、図４の実施例とは直流高電圧発生回路ＨＤをダイオードＤＲ３とトランジスタＴＲ２との接続点と電極側出力端子Ｔｍ１との間に接続した点のみが異なり、その他は、図４の実施例と同様である。
【００１８】
図６の実施例において、アーク起動時はトランジスタＴＲ２を導通させ、同時に直流高電圧発生回路ＨＤに出力を開始させることによって、直流高電圧発生回路ＨＤの正側はトランジスタＴＲ２、被溶接物側出力端子Ｔｍ２を経て被溶接物７に、負側は被溶接物側出力端子Ｔｍ１を経て電極６に加わり、電極６と被溶接物７との間に火花放電を発生させる。もちろん、トランジスタＴＲ４とダイオードＤＲ５とを高耐圧のものにして副スイッチング回路の電磁接触器Ｓ１を省略してもよい。図６においても、リアクトルＬ１（１／２）とダイオードＤＲ３およびトランジスタＴＲ２とダイオードＤＲ４との並列回路の順序およびリアクトルＬ１（２／２）と電磁接触器Ｓ１とトランジスタＴＲ３とダイオードＤＲ５との並列回路の順序は図示の通りでなくてもよい。
【００１９】
図７は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、２および１１の発明の実施例に相当する。同図においては、２次整流回路としてインバータトランスＴ１の出力をダイオードＤＲ２ａとＤＲ２ｂとによって両波整流するとともにリアクトルＬ２を介して正および負の出力端子を有する直流電源を構成している。また、主スイッチング回路は、トランジスタＴＲ４ａないしＴＲ４ｄからなるフルブリッジ回路を使用する。さらに単一の巻線からなるリアクトルＬ２を２次整流回路と主スイッチング回路との間に接続し、ダイオードＤＲ３は副スイッチング回路Ｓ１と並列にして主スイッチング回路と出力端子Ｔｍ２との間に直列に接続し、直流高電圧発生回路ＨＤは出力端子Ｔｍ１とＴｍ２との間に接続されている。したがって、図７は図２の実施例の変形例に相当する。
【００２０】
同図の実施例においては、主スイッチング回路はトランジスタＴＲ４ａとＴＲ４ｄおよびトランジスタＴＲ４ｂとＴＲ４ｃとがそれぞれ１組となって同時にかつ各組のトランジスタが交互にＯＮ−ＯＦＦすることによって出力極性の切り替えが行われる。同図においてアーク起動時には、トランジスタＴＲ４ｂとＴＲ４ｃとが導通し、同時に直流高電圧発生回路ＨＤが出力を開始する。これによって電極６と被溶接物７との間に火花放電が発生し、これに誘発されて２次整流回路からの出力が溶接アークを発生する。溶接アーク起動後は直流高電圧発生回路ＨＤを停止させ、電磁接触器Ｓ１をＯＮし、以後トランジスタＴＲ４ａないしＴＲ４ｄを所定の順序でＯＮ−ＯＦＦ制御することによって交流アーク溶接または所定の極性の直流アーク溶接を行う。
【００２１】
図８は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、２、１１および１６の発明の実施例に相当する。同図においては、図７の実施例に２個のリアクトルＬ３（１／２）とＬ３（２／２）とを電極側および被溶接物側の各出力回路に直列に接続したもので、その他は図７に示した実施例と同様である。同図において、リアクトルＬ３（１／２）とＬ３（２／２）とは図２の実施例において用いたリアクトルリアクトルＬ１（１／２）とＬ１（２／２）と同様に鉄心を共有し、各リアクトルに流れる電流によって共有する鉄心に同方向の磁束を発生する極性に各リアクトルの巻線の巻き方向が定められている。
【００２２】
同図の実施例においても、アーク起動時にトランジスタＴＲ４ｂとＴＲ４ｃとを導通させ直流高電圧発生回路ＨＤを動作開始させることによって電極と被溶接物との間に火花放電が発生し溶接アークに移行する。溶接アーク起動後は直流高電圧発生回路ＨＤを停止させ、電磁接触器Ｓ１をＯＮとすることによつて溶接を行う。このときリアクトルＬ３（１／２）とＬ３（２／２）との作用によつて図２に示した実施例と同様に極性の切り替え時に急峻に電流が切り替えられ、かつこの極性切り替えの瞬間にアークが一旦消滅したときに高いサージ電圧が発生するのでアークの再点孤が確実となる。この場合もトランジスタＴＲ４ａ、ＴＲ４ｄの組とトランジスタＴＲ４ｂ、ＴＲ４ｃの組との各組の導通期間を極く短時間の重なり期間をもって切り替えるようにすればリアクトルＬ３（１／２）Ｌ３（２／２）に流れる電流の急変するときがアークの再点孤すべきときと一致してさらに確実なアーク再点孤が実現できる。それ故、図８は図２および図７の実施例の変形例に相当する。
【００２３】
図９は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、３および１１の発明の実施例に相当する。図９においては、２次整流回路を両波整流するとともにリアクトルＬ２を介して正および負の出力端子を有する回路とし、直流高電圧発生回路ＨＤを副スイッチング回路Ｓ１と並列にして出力回路に直列に挿入したものである。それ故、図９の実施例は図３の変形例に相当し、動作はリアクトルＬ１（１／２）、Ｌ１（２／２）の部分を除いて図３と同様である。
【００２４】
図１０は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、３、１１および１６の発明の実施例に相当する。図１０においては図９の実施例に図８の実施例と同様に２個のリアクトルＬ３（１／２）またはＬ３（２／２）を出力回路に直列に挿入したものであり、その動作はリアクトルの作用を除いて図９の実施例と同様であり、またリアクトルＬ３の作用は図３および図８の実施例と同様である。それ故、図１０の実施例は図３および図９の実施例の変形例に相当する。
【００２５】
図１１は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、２、４および１２の発明の実施例に相当する。同図においては、図４とは２次整流回路を両波整流するとともにリアクトルＬ２を介して正および負の出力端子を有する回路とし、かつ主スイッチング回路がトランジスタＴＲ４ａないしＴＲ４ｄからなるブリッジ回路を構成しており、ブリッジ回路の一方の極性の出力回路にダイオードＤＲ３がまた他方の極性の出力回路に副スイッチング回路の電磁接触器Ｓ１がそれぞれ直列に挿入されている点が異なるのみでその他は変わるところはない。それ故、図１１は図４の実施例の変形例に相当し、その動作はリアクトルＬ１（１／２）およびＬ１（２／２）の動作を除いて図４と同様である。
【００２６】
図１２は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、２、４、１２および１６の発明の実施例に相当する。図１２においては図１１の実施例に図８の実施例と同様に２個のリアクトルＬ３（１／２）およびＬ３（２／２）を出力回路に直列に挿入したものであり、その動作はリアクトルの作用を除いて図１１の実施例と同様であり、またリアクトルＬ３（１／２）およびＬ３（１／２）の作用は図４および図８の実施例と同様である。それ故、図１２は図４および図１１の実施例の変形例に相当する。
【００２７】
図１３は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、３、５および１３の発明の実施例に相当する。同図は、図５とは２次整流回路を両波整流するとともにリアクトルＬ２を介して正および負の出力端子を有する回路とし、かつ主スイッチング回路がトランジスタＴＲ４ａないしＴＲ４ｄからなるブリッジ回路を構成しており、ブリッジ回路の一方の極性の出力回路にダイオードＤＲ３と直流高電圧発生回路ＨＤとの並列回路がまた他方の極性の出力回路に副スイッチング回路の電磁接触器Ｓ１がそれぞれ直列に挿入されている点が異なるのみでその他は変わるところはない。それ故、図１３は図５の実施例の変形例に相当し、その動作はリアクトルＬ１（１／２）およびＬ１（２／２）を除いて図５と同様である。
【００２８】
図１４は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、３、５、１３および１６の発明の実施例に相当する。図１４においては図１３の実施例に図８の実施例と同様に２個のリアクトルＬ３（１／２）またはＬ３（２／２）を出力回路に直列に挿入したものであり、その動作はリアクトルの作用を除いて図１３の実施例と同様であり、またリアクトルＬ３の作用は図４および図８の実施例と同様である。それ故、図１４は図５および図１３の実施例の変形例に相当する。
【００２９】
図１５は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１および１４の発明の実施例に相当する。同図において２次整流回路は図７ないし図１４の実施例と同様に両波整流するとともにリアクトルＬ２を介して正および負の出力端子を有する回路のものを使用しており、直流高電圧発生回路ＨＤは図示のようにブリッジ接続された主スイッチング回路の直流入力側に並列に接続されており、副スイッチング回路はトランジスタＴＲ４ａとＴＲ４ｄとを回路から切り離すように２個の電磁接触器Ｓ１ａとＳ１ｂとしてブリッジ回路に直列に接続されている。同図の実施例において、アーク起動時はトランジスタＴＲ４ｂとＴＲ４ｃとをＯＮとし、同時に直流高電圧発生回路ＨＤの動作を開始させると被溶接物７に正、電極６に負の極性の電圧が供給され、両者間に火花放電が発生する。この火花放電に２次整流回路の出力が重畳されてアークが成長して溶接が開始される。アークが確立した後は上記の各実施例と同様に直流高電圧発生回路ＨＤをＯＦＦし副スイッチング回路の電磁接触器Ｓ１ａとＳ１ｂとをＯＮとした後にトランジスタＴＲ４ａないしＴＲ４ｄを所定の順序でＯＮ−ＯＦＦすることによって直流または交流アーク溶接を実施することができる。
【００３０】
図１６は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、１４および１６の発明の実施例に相当する。同図においては図１５の実施例に図８の実施例と同様にリアクトルＬ３（１／２）およびＬ３（２／２）を出力回路に直列に挿入したものであり、その動作はリアクトルＬ３（１／２）およびＬ３（２／２）を除いては図１５と同様であり、リアクトルＬ３（１／２）およびＬ３（２／２）は図８と同様に作用する。また、電磁接触器Ｓ１ｂは直流高電圧発生回路ＨＤの動作時に開路状態に保ち、起動時遮断状態のトランジスタＴＲ４ｄが直流高電圧発生回路ＨＤの出力高電圧によって破壊されるのを防止している。
【００３１】
図１７は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、３および１５の実施例に相当する。同図において２次整流回路は図７ないし図１６の実施例と同様に両波整流するとともにリアクトルＬ２を介して正および負の出力端子を有する回路のものを使用しており、直流高電圧発生回路ＨＤは図示のようにブリッジ接続された主スイッチング回路の直流入力側に直列接続されたダイオードＤＲ３に並列に接続されており、副スイッチング回路はトランジスタＴＲ４ａとＴＲ４ｄとを回路から切り放すように２個の電磁接触器Ｓ１ａとＳ１ｂがブリッジ回路に直列に接続されている。同図の実施例において、アーク起動時はトランジスタＴＲ４ｂとＴＲ４ｃとをＯＮとし、同時に直流高電圧発生回路ＨＤの動作を開始させると、被溶接物７に正、電極６に負の極性の電圧が供給され、両者間に火花放電が発生する。この火花放電に２次整流回路ＤＲ２の出力が重畳されてアークが成長し溶接が開始される。アークが確立した後は、上記の各実施例と同様に直流高電圧発生回路ＨＤをＯＦＦし、副スイッチング回路の電磁接触器Ｓ１ａとＳ１ｂとをＯＮとした後にトランジスタＴＲ４ａないしＴＲ４ｄを所定の順序でＯＮ−ＯＦＦすることによって直流または交流アーク溶接を実施することができる。それ故、図１７の実施例は図５の実施例の変形例に相当する。
【００３２】
図１８は、本発明をアーク溶接に適用したときの別の実施例を示す接続図であり、請求項１、３、１５および１６の発明の実施例に相当する。同図においては図１７の実施例に図８の実施例と同様にリアクトルＬ３（１／２）およびＬ３（２／２）を出力回路に直列に挿入したものであり、その動作はリアクトルＬ３（１／２）およびＬ３（２／２）を除いては図１７と同様であり、リアクトルＬ３（１／２）およびＬ３（２／２）は図８と同様に作用する。それ故、図１８の実施例は図５および図１７の実施例の変形例に相当する。
【００３３】
上記各実施例においては、本発明をアーク溶接に適用する場合について説明したが、本発明はアーク溶接のみに限られるものではなく、アーク切断、アーク加熱、アーク溶融などアーク応用加工装置に適用できることはもちろんである。
【００３４】
【発明の効果】
本発明のアーク加工装置は、アーク起動用の直流高電圧が２次回路に侵入しないようにするダイオードとアーク起動時とは逆向きの出力電流を流せるようにする副スイッチ回路を用いることにより、直流出力のみでなく交流出力も得ることができる、交直両用のアーク加工装置を実現できる。
【図面の簡単な説明】
【図１】従来のアーク加工装置の例を示接続図、
【図２】本発明の請求項１、２および６の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図３】本発明の請求項１、３および７の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図４】本発明の請求項１、２、４および８の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図５】本発明の請求項１、３、５および９の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図６】本発明の請求項１および１０の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図７】本発明の請求項１、２および１１の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図８】本発明の請求項１、２、１１および１６の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図９】本発明の請求項１、３および１１の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図１０】本発明の請求項１、３、１１および１６の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図１１】本発明の請求項１、２、４および１２の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図１２】本発明の請求項１、２、４、１２および１６の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図１３】本発明の請求項１、３、５および１３の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図１４】本発明の請求項１、３、５、１３および１６の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図１５】本発明の請求項１および１４の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図１６】本発明の請求項１、１４および１６の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図１７】本発明の請求項１、３および１５をの発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【図１８】本発明の請求項１、３、１５および１６の発明を交直両用アーク溶接機に実施したときの例を示す接続図、
【符号の説明】
１ないし３１次入力線
４溶接電源
５電極側ケーブル
６電極
７被溶接物
８被溶接物側ケーブル
９、１０溶接電源
１１第位置１の直流電源
１５第２の直流電源
１６ダイオード
１８アーク発生検出手段
１９スイッチ手段
ＤＲ１１次整流器
ＤＲ２２次整流回路
ＤＲ２ａないしＤＲ２ｄ２次整流回路を構成するダイオード
ＤＲ３、ＤＲ４、ＤＲ５ダイオード
ＤＲ６ａないしＤＲ６ｄダイオード
Ｔ１インバータトランス
Ｌ１（１／２）、Ｌ１（２／２）リアクトル
Ｌ２リアクトル
Ｌ３（１／２）、Ｌ３（２／２）リアクトル
ＴＲ１インバータ回路
ＴＲ２およびＴＲ３トランジスタ
ＴＲ４ａないしＴＲ４ｄトランジスタ
Ｓ１、Ｓ１ａ、Ｓ１ｂ副スイッチング回路（電磁接触器）
ＨＤ直流高電圧発生回路
ＴＳ１起動スイッチ
ＲＶ１出力電流調整器
ＣＴ１出力電流検出器
Ｔｍ１電極側出力端子
Ｔｍ２被溶接物側出力端子
Ｃ１平滑コンデンサ
ＣＬ１、ＣＬ２制御回路[0001]
[Industrial application fields]
The present invention proposes an apparatus having improved arc starting performance in an arc machining apparatus used for AC / DC arc welding, cutting or arc heating.
[0002]
[Prior art]
FIG. 1 is an example of a conventional arc welding apparatus. In FIG. 1, 1 to 3 are primary input lines, 5 is an electrode side cable, 6 is an electrode, 7 is an article to be welded, 8 is a cable to be welded, and TS1 is a start switch. In the welding power source 4, 11 is a first DC power source, and 15 is a second DC power source, which is a circuit that generates a DC high voltage. Reference numeral 16 denotes a diode which can withstand a high DC voltage generated by the second DC power source and has a capacity for flowing a welding current. Reference numeral 18 denotes an arc generation detecting means, which determines that an arc has been generated depending on whether or not a normal arc current is flowing. 19 is a switch means that receives an activation signal from the activation switch TS1, issues a command to a gas supply circuit (not shown), starts supplying shield gas around the electrode, and the shield gas reaches around the electrode. The first DC power supply 11 and the second DC power supply 15 are operated. The high DC voltage generated by the second DC power supply 15 is blocked by the diode 16 and is not applied to the first DC power supply 11, but is applied only between the electrode 6 and the workpiece 7 and breaks the insulation between them. Generates a spark discharge. Electric power is supplied to the spark discharge from the first DC power source, and the spark discharge grows into a welding arc.
[0003]
[Problems to be solved by the invention]
The conventional apparatus shown in FIG. 1 can be applied only to a DC output type, and its output polarity is fixed. Therefore, only the output of the polarity determined by the apparatus is supplied to the arc processing unit, and the positive arc is positive on the workpiece side and the electrode side is positive depending on the material and processing method of the workpiece. This method cannot be applied to both AC and DC applications, such as switching the reverse polarity arc or the positive / reverse polarity arc at a predetermined ratio to obtain an AC output.
[0004]
[Means for Solving the Problems]
The present invention includes a main switching circuit that supplies an arc machining load by switching the output of a DC power source to normal and reverse polarity, and a DC high voltage generation circuit for supplying a high voltage for arc starting to the arc machining load; A diode connected in series between the DC power source and the load output terminal and having the same polarity as that of the DC high voltage generation circuit, a sub switching circuit for passing an output having a polarity opposite to the output polarity of the DC high voltage generation circuit, and arc starting At this time, the DC high voltage generating circuit is started and the main switching circuit is driven so as to supply an output having the same polarity as the output of the DC high voltage generating circuit to the arc machining load. The above-described structure is provided with a control circuit that shuts off and makes the sub-switching circuit conductive, and that controls the main switching circuit in a predetermined order. It is obtained by solving the problems of the coming devices.
[0005]
【Example】
Hereinafter, the present invention will be described with reference to the illustrated embodiments. FIG. 2 is a connection diagram showing an embodiment when the present invention is applied to AC / DC arc welding, and corresponds to the embodiments of claims 1, 2 and 6. In FIG. 2, 1 to 3 are primary input lines, 5 is an electrode side cable, 6 is an electrode, 7 is an object to be welded, 8 is a cable to be welded, TS1 is a start switch, and RV1 is an output current regulator. . In the welding power source 9, DR1 is a primary rectifier, C1 is a smoothing capacitor, TR1 is an inverter circuit, T1 is an inverter transformer, L1 (1/2) and L1 (2/2) are reactors, and both reactors have a common iron core. Consists of a coil wound around Each In the figure, the polarity is determined to be a polarity that generates a magnetic flux in the same direction in the iron core shared by the currents flowing through each of the switching elements TR2 and TR3 connected in series, as indicated by a mark. TR2 and TR3 are transistors constituting the main switching circuit , C T1 is a current detector, Tm1 is a workpiece output terminal, and Tm2 is an electrode output terminal. Normally, diodes are connected in antiparallel to the transistors TR2 and TR3, but these diodes are not shown in order to prevent the figure from becoming complicated.
[0006]
In FIG. 2, DR3 is a diode, S1 is an electromagnetic contactor constituting a sub-switching circuit, HD is a DC high voltage generation circuit, and CL2 is a control circuit. Note that the DC high voltage generation circuit HD has a high no-load voltage but a large output impedance, and its output current is limited to the extent that spark discharge is generated between the electrode 6 and the workpiece 7.
[0007]
In FIG. 2, three-phase commercial frequency alternating current is applied from the primary input lines 1 to 3, and the primary rectifier DR1 rectifies this to direct current. The output is smoothed by the smoothing capacitor C1. The inverter circuit TR1 converts the output smoothed by the smoothing capacitor C1 into an alternating voltage having a frequency higher than the commercial frequency and supplies it to the primary winding of the inverter transformer T1. The turn ratio of the inverter transformer T1 is selected so that a voltage suitable for welding can be obtained in the secondary winding. The secondary rectifier circuit DR2 rectifies the output voltage of the inverter transformer T1. One of the transistors TR2 and TR3 is turned on and the other is turned off to switch the polarity of the welding output. When the transistor TR2 is now ON and the transistor TR3 is OFF, the welding current is the positive output terminal of the secondary rectifier circuit DR2, the reactor L1 (1/2), the transistor TR2, the diode DR3, the workpiece-side output terminal Tm2, A welded-side cable 8, an object to be welded 7, an electrode 6, an electrode-side cable 5, an electrode-object-side output terminal Tm 1, and a current detector CT 1 flow through the path, and a positive arc is formed between the object to be welded 7 and the electrode 6. generate. The output current detector CT1 detects an arc current and sends a detection signal to the control circuit CL2. The control circuit CL2 compares the output current command signal from the output regulator RV1 with the detection signal of the output current detector CT1, and sends a command signal that reduces the difference to the inverter circuit TR1. As a result, the output current of the welding power source 4 is maintained at the set value of the output adjuster RV1.
[0008]
Next, when the transistor TR2 is turned off and the transistor TR3 is turned on, the current flowing through the transistor TR2 to the reactor L1 (1/2) and the current flowing through the transistor TR3 into the reactor L1 (2/2) magnetize the iron core in the same direction. Therefore, the current flowing through the reactor L1 (1/2) moves to the reactor L1 (2/2) and flows. As a result, the welding current is the zero output terminal of the secondary rectifier circuit DR2, the output current detector CT1, the electrode side output terminal Tm1, the electrode side cable 5, the electrode 6, the work piece 7, the work piece side cable 8, the electromagnetic contact. Flows through the path of the negative output terminal of the secondary device rectifier circuit DR2 by generating a reverse-polarity arc between the electrode 6 and the workpiece 7 to be welded. An alternating arc is obtained between the electrode 6 and the workpiece 7 by alternately repeating the state in which the transistor TR2 is ON and the transistor TR3 is OFF and the state in which the transistor TR2 is OFF and the transistor TR3 is ON.
[0009]
Next, the operation at the time of arc starting will be described. In FIG. 2, when the activation switch TS1 is pressed, the control circuit CL2 issues a command to a gas supply circuit (not shown) to start supplying shield gas around the electrodes. The control circuit CL2 commands the inverter circuit TR1 to start operation, the transistor TR2 to turn on, the electromagnetic contactor S1 to turn off, and the output to the DC high voltage generation circuit HD. Command to start The voltage of the DC high voltage generating circuit HD is blocked by the diode DR3 and the open electromagnetic contactor S1 and does not reach the transistor TR2 and transistor TR3 side, but is applied between the electrode 6 and the workpiece 7 and insulation between them is performed. Break and generate a spark discharge. This spark discharge has a small output current due to the high internal impedance of the DC high voltage generation circuit HD. However, a current of the same polarity passes from the secondary rectifier circuit DR2 to the reactor L1 (1/2), the transistor TR2, and the diode DR3. Since they flow in a superimposed manner, the spark discharge current increases rapidly and grows into a welding arc. The output current detector CT1 sends a welding current detection signal to the control circuit CL2, and this control signal instructs the control circuit CL2 to stop the operation of the DC high voltage generation circuit HD. When performing DC arc welding, the transistor TR2 is turned on. When the transistor TR3 is turned off and the electromagnetic contactor S1 is kept off and the AC arc welding is performed, the electromagnetic contactor S1 is turned on, and then the transistor TR2 and the transistor TR3 are alternately turned on and off. The magnetic contactor S1 may use a semiconductor switching element such as a thyristor that allows a current in the direction opposite to that of the diode DR3 to flow.
[0010]
Here, at the time of AC output, magnetic fluxes in the same direction are generated in the iron core sharing the windings of the reactor L1 (1/2) and the reactor L1 (2/2) by the current flowing through each coil as described above. If the winding direction is determined in advance, the current that has been flowing through the reactor L1 (1/2) when the transistor TR2 is switched from ON to OFF during the polarity inversion will be transferred to the reactor L1 (2/2) as it is. And For this reason, a high surge voltage is generated simultaneously with the turning-off of the transistor TR2, and assists the regeneration of the arc. Further, the transistors TR2 and TR3 are preferably turned on and off alternately with a very short conduction period and with a short overlap, so that both transistors may be controlled substantially without a gap. When this is done, the arc disappears during the overlap time of the transistors TR2 and TR3, but the current is short-circuited by the transistors TR2 and TR3 through the reactor, and the value is suppressed by the reactor. . When the transistor TR2 is turned off in this state, a high surge voltage is generated in the forward direction of the transistor TR3 so as to maintain the current that was flowing in the reactor immediately before. This surge voltage is applied between the electrode 6 and the specific welding object 7 with the opposite polarity to the previous one, and the transistor TR3 is already in a conductive state, so that the electrode 6 and the workpiece to be welded at the moment when the transistor TR2 is turned off. 7 and the arc regeneration is more reliable.
[0011]
In TIG arc welding, when the arc is started from the positive polarity as described above, the establishment of the arc may become unstable. In such a case, the polarities of the DC high voltage generation circuit HD and the diode DR3 are reversed from those shown in the figure, the transistor TR3 is turned on at the time of activation, the transistor TR2 is turned off, and the arc is established from the opposite polarity. The transistor TR2 or the transistor TR3 may be turned on or off so that the desired polarity is detected, and the electromagnetic contactor S1 may be opened and closed accordingly.
[0012]
FIG. 3 shows another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the inventions of claims 1, 3 and 7. In the figure, reference numeral 10 denotes a welding power source, and unlike the embodiment shown in FIG. 2, a DC high voltage generating circuit HD is connected in series to an output circuit. The positive side output of the DC high voltage generating circuit HD is to the workpiece 7 through the workpiece side output terminal Tm2 and the workpiece side cable 8, and the negative side output is the transistor TR2, reactor L1 (1/2), 2 The secondary rectifier circuit DR2, the electrode side output terminal Tm1, and the electrode side cable 5 are supplied to the electrode 6 respectively. After the spark discharge is generated between the electrode 6 and the workpiece 7 by this DC high voltage, the operation is the same as that of the embodiment shown in FIG. 2 and FIG. 3, the order of reactor L1 (1/2) and transistor TR2 and the order of reactor L1 (2/2) and transistor TR3 may be opposite to those shown in the drawings.
[0013]
FIG. 4 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the first, fourth and eighth aspects of the present invention. In this figure, in order to avoid complicated explanation, the same parts as those in FIG. 3 not shown in FIG.
[0014]
In FIG. 4, DR2a to DR2d are diodes constituting each element of the secondary rectifier circuit DR2, DR3 is a diode, DR4 and DR5 are diodes, and S1 is an electromagnetic contactor constituting a sub switching circuit.
[0015]
In FIG. 4, when the arc is activated, the transistor TR2 is turned on, the transistor TR3 is turned off, and the electromagnetic contactor S1 is turned off to operate the DC high voltage generation circuit HD. The output voltage of the DC high voltage generating circuit HD is that the positive side is the workpiece-side output terminal Tm2 and the workpiece-side cable 8 to the workpiece-side 7 and the negative side is the electrode-side output terminal Tm1 and the electrode-side cable 5 To the electrode 6 to generate a spark discharge between the work piece 7 and the electrode 6, and a current flows through the spark discharge from the diodes DR2a and DR2b through the reactor L1 (1/2), the diode DR3, and the transistor TR2. The spark discharge grows into a welding arc. The diode DR3 prevents the diode DR2a and the diode DR2b and the transistor TR2 in the ON state from being applied with the DC high voltage of the DC high voltage generation circuit HD, and the electromagnetic contactor S1 applies the DC high voltage to the diode DR5 and the transistor TR3 in the OFF state. The generation circuit HD is prevented from being applied with a DC high voltage, and is turned ON during AC welding to pass a current through the transistor TR3. In addition, the order of connection of the parallel circuit of reactor L1 (1/2), diode DR3, transistor TR2 and diode DR4, reactor L1 (2/2), electromagnetic contactor S1, parallel circuit of transistor TR3 and diode DR5 The order of connection may not be as illustrated.
[0016]
FIG. 5 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the inventions of claims 1, 5 and 9. In FIG. 4, only the inverter transformer T1 and subsequent parts are shown as in FIG.
In FIG. 5, a DC high voltage generating circuit HD is connected in parallel to a diode DR3 and connected in series between a reactor L1 (1/2) and a transistor TR2, and an electromagnetic contactor S1 as a sub-switching circuit is connected to the reactor L1. (2/2) and the transistor TR3 are connected in series. The positive voltage of the DC high voltage generating circuit HD is supplied to the workpiece 7 via the transistor TR2, the workpiece-side output terminal Tm2, the workpiece-side cable 8, and the negative voltage is the reactor L1 (1/2 ), The diode DR2a or the diode DR2b, the inverter transformer T1, the workpiece-side output terminal Tm1, and the electrode-side cable 5 to be applied to the electrode 6. When a transistor and a diode that can withstand the DC high voltage of the DC high voltage generating circuit HD are used in the parallel circuit of the transistor TR3 and the diode DR5, the electromagnetic contactor S1 may be omitted. Also in FIG. 5, the order of the parallel circuit of reactor L1 (1/2), diode DR3, transistor TR2 and diode DR4, and the parallel circuit of reactor L (2/2), electromagnetic contactor S1, transistor TR3 and diode DR5 The order may not be as illustrated.
[0017]
FIG. 6 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the invention of claims 1 and 10. In FIG. 6 as well, only the inverter lance T1 and after are shown as in the embodiment shown in FIG. 4. The embodiment shown in FIG. 4 differs from the embodiment shown in FIG. 4 in that the DC high voltage generating circuit HD is connected to the connection point between the diode DR3 and the transistor TR2. The only difference is that it is connected to the output terminal Tm1, and the rest is the same as in the embodiment of FIG.
[0018]
In the embodiment of FIG. 6, when the arc is activated, the transistor TR2 is turned on and at the same time the DC high voltage generating circuit HD starts outputting, so that the positive side of the DC high voltage generating circuit HD is the transistor TR2 and the workpiece side output. The negative side is applied to the work piece 7 via the terminal Tm2 and the negative side is applied to the electrode 6 via the work piece side output terminal Tm1, and a spark discharge is generated between the electrode 6 and the work piece 7. Of course, the transistor TR4 and the diode DR5 may have a high breakdown voltage, and the electromagnetic contactor S1 of the sub-switching circuit may be omitted. Also in FIG. 6, the order of the parallel circuit of reactor L1 (1/2), diode DR3 and transistor TR2 and diode DR4, and the parallel circuit of reactor L1 (2/2), electromagnetic contactor S1, transistor TR3 and diode DR5 The order may not be as illustrated.
[0019]
FIG. 7 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the first, second and eleventh aspects of the present invention. In the figure, as a secondary rectifier circuit, an output of an inverter transformer T1 is rectified by both waves by diodes DR2a and DR2b, and a DC power source having positive and negative output terminals via a reactor L2 is configured. The main switching circuit uses a full bridge circuit composed of transistors TR4a to TR4d. Further, a reactor L2 composed of a single winding is connected between the secondary rectifier circuit and the main switching circuit, and the diode DR3 is connected in series with the sub switching circuit S1 between the main switching circuit and the output terminal Tm2. The DC high voltage generation circuit HD is connected between the output terminals Tm1 and Tm2. Accordingly, FIG. 7 corresponds to a modification of the embodiment of FIG.
[0020]
In the embodiment shown in the figure, the main switching circuit switches the output polarity by turning on and off the transistors TR4a and TR4d and the transistors TR4b and TR4c at the same time. Is called. In the figure, at the time of arc starting, the transistors TR4b and TR4c are brought into conduction, and at the same time, the DC high voltage generating circuit HD starts outputting. As a result, a spark discharge is generated between the electrode 6 and the workpiece 7 and is induced by this, and the output from the secondary rectifier circuit generates a welding arc. After starting the welding arc, the DC high voltage generating circuit HD is stopped, the magnetic contactor S1 is turned on, and then the transistors TR4a to TR4d are turned on and off in a predetermined order to perform AC arc welding or a DC arc of a predetermined polarity. Weld.
[0021]
FIG. 8 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiments of the inventions of claims 1, 2, 11 and 16. In this figure, the reactors L3 (1/2) and L3 (2/2) are connected in series to the output circuits on the electrode side and the workpiece side in the embodiment of FIG. Is the same as the embodiment shown in FIG. In the figure, reactors L3 (1/2) and L3 (2/2) share the same iron core as reactors L1 (1/2) and L1 (2/2) used in the embodiment of FIG. The winding direction of the winding of each reactor is determined so as to generate a magnetic flux in the same direction in the iron core shared by the current flowing through each reactor.
[0022]
Also in the embodiment shown in the figure, when the arc is activated, the transistors TR4b and TR4c are turned on to start the operation of the DC high-voltage generation circuit HD, so that a spark discharge is generated between the electrode and the workpiece and the welding arc is shifted to. . After starting the welding arc, welding is performed by stopping the DC high voltage generating circuit HD and turning on the magnetic contactor S1. At this time, due to the action of the reactors L3 (1/2) and L3 (2/2), as in the embodiment shown in FIG. 2, the current is switched sharply at the time of polarity switching, and at the moment of this polarity switching. Since a high surge voltage is generated once the arc is extinguished, the arc can be re-pointed. Also in this case, the reactor L3 (1/2) L3 (2/2) can be switched by switching the conduction period between the pair of transistors TR4a and TR4d and the pair of transistors TR4b and TR4c with a very short overlap period. A more reliable arc re-arcing can be realized in accordance with the time when the current flowing through the current changes suddenly. Therefore, FIG. 8 corresponds to a modification of the embodiment of FIGS.
[0023]
FIG. 9 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the first, third and eleventh aspects of the present invention. In FIG. 9, the secondary rectifier circuit is rectified in both waves and has a positive and negative output terminal via a reactor L2, and the DC high voltage generation circuit HD is connected in parallel with the sub-switching circuit S1 and connected in series with the output circuit. It is inserted in. Therefore, the embodiment of FIG. 9 corresponds to the modification of FIG. 3, and the operation is the same as that of FIG. 3 except for the reactors L1 (1/2) and L1 (2/2).
[0024]
FIG. 10 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the invention of claims 1, 3, 11 and 16. In FIG. 10, two reactors L3 (1/2) or L3 (2/2) are inserted in series in the output circuit in the embodiment of FIG. 9 as in the embodiment of FIG. Except for the action of the reactor, it is the same as the embodiment of FIG. 9, and the action of the reactor L3 is the same as that of the embodiment of FIGS. Therefore, the embodiment of FIG. 10 corresponds to a modification of the embodiment of FIGS.
[0025]
FIG. 11 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiments of the first, second, fourth and twelfth aspects of the present invention. In FIG. 4, the secondary rectifier circuit is double-wave rectified and has a positive and negative output terminal via a reactor L2, and a main switching circuit constitutes a bridge circuit composed of transistors TR4a to TR4d. The only difference is that the diode DR3 is inserted in the output circuit of one polarity of the bridge circuit and the electromagnetic contactor S1 of the sub-switching circuit is inserted in series in the output circuit of the other polarity. There is no. Therefore, FIG. 11 corresponds to a modification of the embodiment of FIG. 4, and its operation is the same as that of FIG. 4 except for the operations of reactors L1 (1/2) and L1 (2/2).
[0026]
FIG. 12 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the inventions of claims 1, 2, 4, 12 and 16. In FIG. 12, two reactors L3 (1/2) and L3 (2/2) are inserted in series in the output circuit in the embodiment of FIG. 11 as in the embodiment of FIG. Except for the operation of the reactor, it is the same as the embodiment of FIG. 11, and the operations of the reactors L3 (1/2) and L3 (1/2) are the same as those of the embodiment of FIGS. Therefore, FIG. 12 corresponds to a modification of the embodiment of FIGS.
[0027]
FIG. 13 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiments of the inventions of claims 1, 3, 5 and 13. This figure is different from FIG. 5 in that a secondary rectifier circuit is rectified in both waves and a circuit having positive and negative output terminals via a reactor L2, and a main switching circuit constitutes a bridge circuit composed of transistors TR4a to TR4d. The parallel circuit of the diode DR3 and the DC high voltage generating circuit HD is inserted in the output circuit of one polarity of the bridge circuit, and the electromagnetic contactor S1 of the sub-switching circuit is inserted in series in the output circuit of the other polarity. The only difference is that there are no changes. Therefore, FIG. 13 corresponds to a modification of the embodiment of FIG. 5, and its operation is the same as that of FIG. 5 except for the reactors L1 (1/2) and L1 (2/2).
[0028]
FIG. 14 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the invention of claims 1, 3, 5, 13 and 16. In FIG. 14, two reactors L3 (1/2) or L3 (2/2) are inserted in series in the output circuit in the embodiment of FIG. 13 as in the embodiment of FIG. Except for the operation of the reactor, it is the same as the embodiment of FIG. 13, and the operation of the reactor L3 is the same as that of the embodiment of FIGS. Therefore, FIG. 14 corresponds to a modification of the embodiment of FIGS.
[0029]
FIG. 15 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the inventions of claims 1 and 14. In the same figure, the secondary rectifier circuit uses a circuit having both positive and negative output terminals via a reactor L2 as well as rectifying both waves in the same manner as in the embodiments of FIGS. The circuit HD is connected in parallel to the DC input side of the bridge-connected main switching circuit as shown, and the sub-switching circuit has two electromagnetic contactors S1a and S1b so as to disconnect the transistors TR4a and TR4d from the circuit. Connected in series to the bridge circuit. In the embodiment shown in the figure, when the arc is activated, the transistors TR4b and TR4c are turned on, and at the same time, the operation of the DC high voltage generation circuit HD is started, so that a positive polarity voltage is supplied to the work 7 and a negative polarity to the electrode 6. A spark discharge occurs between the two. The output of the secondary rectifier circuit is superimposed on this spark discharge, an arc grows, and welding is started. After the arc is established, the DC high voltage generating circuit HD is turned off and the electromagnetic contactors S1a and S1b of the sub-switching circuit are turned on, and the transistors TR4a to TR4d are turned on in a predetermined order. By turning it off, direct current or alternating current arc welding can be performed.
[0030]
FIG. 16 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the invention of claims 1, 14 and 16. In FIG. 15, reactors L3 (1/2) and L3 (2/2) are inserted in series in the output circuit in the same manner as in the embodiment of FIG. Except for 1/2) and L3 (2/2), it is the same as in FIG. 15, and reactors L3 (1/2) and L3 (2/2) act in the same way as in FIG. Further, the electromagnetic contactor S1b is kept open when the DC high voltage generation circuit HD is in operation, and prevents the transistor TR4d in the cut-off state at startup from being destroyed by the output high voltage of the DC high voltage generation circuit HD.
[0031]
FIG. 17 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiments of claims 1, 3 and 15. In the same figure, the secondary rectifier circuit uses a circuit having both positive and negative output terminals via a reactor L2 as well as rectifying both waves in the same manner as in the embodiments of FIGS. The circuit HD is connected in parallel to a diode DR3 connected in series on the DC input side of the bridge-connected main switching circuit as shown in the figure, and the sub-switching circuit 2 disconnects the transistors TR4a and TR4d from the circuit. The electromagnetic contactors S1a and S1b are connected in series to the bridge circuit. In the embodiment shown in the figure, when the arc is activated, the transistors TR4b and TR4c are turned on and simultaneously the operation of the DC high voltage generating circuit HD is started, so that a positive polarity voltage is applied to the workpiece 7 and a negative polarity voltage is applied to the electrode 6. Supplied and spark discharge occurs between them. The output of the secondary rectifier circuit DR2 is superimposed on this spark discharge, an arc grows, and welding is started. After the arc is established, the DC high voltage generating circuit HD is turned off, the sub-switching circuit electromagnetic contactors S1a and S1b are turned on, and the transistors TR4a to TR4d are turned on in a predetermined order. Direct current or alternating current arc welding can be performed by turning on and off. Therefore, the embodiment of FIG. 17 corresponds to a modification of the embodiment of FIG.
[0032]
FIG. 18 is a connection diagram showing another embodiment when the present invention is applied to arc welding, and corresponds to the embodiment of the invention of claims 1, 3, 15 and 16. In FIG. 17, similarly to the embodiment of FIG. 8, reactors L3 (1/2) and L3 (2/2) are inserted in series in the output circuit in the embodiment of FIG. Except for 1/2) and L3 (2/2), it is the same as in FIG. 17, and reactors L3 (1/2) and L3 (2/2) act in the same way as in FIG. Therefore, the embodiment of FIG. 18 corresponds to a modification of the embodiment of FIGS.
[0033]
In each of the above embodiments, the case where the present invention is applied to arc welding has been described. However, the present invention is not limited to arc welding, and can be applied to arc applied machining apparatuses such as arc cutting, arc heating, and arc melting. Of course.
[0034]
【The invention's effect】
The arc machining apparatus of the present invention uses a diode that prevents a DC high voltage for arc starting from entering the secondary circuit and a sub-switch circuit that allows an output current to flow in a direction opposite to that during arc starting, An AC / DC arc machining apparatus capable of obtaining not only a DC output but also an AC output can be realized.
[Brief description of the drawings]
FIG. 1 is a connection diagram illustrating an example of a conventional arc machining apparatus;
FIG. 2 is a connection diagram showing an example when the inventions of claims 1, 2 and 6 of the present invention are applied to an AC / DC arc welder;
FIG. 3 is a connection diagram showing an example when the inventions of claims 1, 3 and 7 of the present invention are applied to an AC / DC arc welder;
FIG. 4 is a connection diagram showing an example when the inventions of claims 1, 2, 4 and 8 of the present invention are applied to an AC / DC arc welder;
FIG. 5 is a connection diagram showing an example when the inventions of claims 1, 3, 5 and 9 of the present invention are applied to an AC / DC arc welder;
FIG. 6 is a connection diagram showing an example when the inventions of claims 1 and 10 of the present invention are implemented in an AC / DC arc welder;
FIG. 7 is a connection diagram showing an example when the invention of claims 1, 2 and 11 of the present invention is applied to an AC / DC arc welder;
FIG. 8 is a connection diagram showing an example when the inventions of claims 1, 2, 11 and 16 of the present invention are applied to an AC / DC arc welder;
FIG. 9 is a connection diagram showing an example when the inventions of claims 1, 3 and 11 of the present invention are applied to an AC / DC arc welder;
FIG. 10 is a connection diagram showing an example when the inventions of claims 1, 3, 11 and 16 of the present invention are applied to an AC / DC arc welder;
FIG. 11 is a connection diagram showing an example when the invention of claims 1, 2, 4 and 12 of the present invention is applied to an AC / DC arc welder;
FIG. 12 is a connection diagram showing an example when the invention of claims 1, 2, 4, 12 and 16 of the present invention is applied to an AC / DC arc welder;
FIG. 13 is a connection diagram showing an example when the inventions of claims 1, 3, 5 and 13 of the present invention are applied to an AC / DC arc welder;
FIG. 14 is a connection diagram showing an example when the inventions of claims 1, 3, 5, 13 and 16 of the present invention are applied to an AC / DC arc welder;
FIG. 15 is a connection diagram showing an example when the invention of claims 1 and 14 of the present invention is applied to an AC / DC arc welder;
FIG. 16 is a connection diagram showing an example when the invention of claims 1, 14 and 16 of the present invention is applied to an AC / DC arc welder;
FIG. 17 is a connection diagram showing an example when the invention according to claims 1, 3 and 15 of the present invention is applied to an AC / DC arc welder;
FIG. 18 is a connection diagram showing an example when the invention of claims 1, 3, 15 and 16 of the present invention is applied to an AC / DC arc welding machine;
[Explanation of symbols]
1 to 3 primary input line
4 Welding power source
5 Electrode side cable
6 electrodes
7 Workpiece
8 Workpiece side cable
9, 10 Welding power supply
11 DC power supply at position 1
15 Second DC power supply
16 diodes
18 Arc generation detection means
19 Switch means
DR1 primary rectifier
DR2 secondary rectifier circuit
DR2a to DR2d Diode constituting secondary rectifier circuit
DR3, DR4, DR5 diode
DR6a to DR6d diode
T1 inverter transformer
L1 (1/2), L1 (2/2) reactor
L2 reactor
L3 (1/2), L3 (2/2) reactor
TR1 inverter circuit
TR2 and TR3 transistors
TR4a to TR4d transistors
S1, S1a, S1b Sub switching circuit (electromagnetic contactor)
HD DC high voltage generator
TS1 start switch
RV1 output current regulator
CT1 output current detector
Tm1 Electrode side output terminal
Tm2 Workpiece output terminal
C1 smoothing capacitor
CL1, CL2 control circuit

Claims

In an AC / DC arc machining apparatus that starts an arc without bringing an electrode into contact with a workpiece, an arc machining load comprising an electrode and a workpiece by switching a DC power source and the output of the DC power source to positive and reverse polarities A main switching circuit for supplying to the arc machining load, a DC high voltage generating circuit for supplying a high voltage for starting the arc to the arc machining load, and the DC high voltage provided in series between the DC power supply and the load output terminal. A diode whose connection direction is determined to be the same as the voltage generation circuit, a sub-switching circuit for passing an output having a polarity opposite to the output polarity of the DC high voltage generation circuit, and the DC high voltage generation circuit at the time of arc starting. The main switching circuit is driven to supply an output having the same polarity as the output of the DC high voltage generation circuit to the arc machining load, After the sub switching circuit is conductive, and universal arc processing apparatus having a control circuit the main switching circuit for ON-OFF control in a predetermined sequence while blocking the output of the high voltage DC generator.

The DC high voltage generating circuit is connected between the load output terminals, and the diode is connected in parallel with the sub-switching circuit and connected in series between one output of the main switching circuit and the load output terminal. The AC / DC dual-purpose arc machining apparatus according to claim 1.

2. The AC / DC converter according to claim 1, wherein the DC high voltage generation circuit, the diode, and the sub-switching circuit are connected in parallel and connected in series between one output of the main switching circuit and the load output terminal. Dual-purpose arc machining device.

The direct current high voltage generation circuit is connected between the load output terminals, and the diode is connected in series in a circuit of a polarity in the main switching circuit that outputs an output in the same direction as the output polarity of the direct current high voltage generation circuit. The AC / DC arc machining according to claim 1, wherein the sub-switching circuit is connected in series in a circuit having a polarity opposite to a polarity to which the diode of the main switching circuit is connected. apparatus.

The diode is connected in parallel with the same polarity as the output polarity of the DC high voltage generation circuit, and is connected in series in a circuit that flows current in the same direction as the output of the DC high voltage generation circuit in the main switching circuit. The sub-switching circuit is connected in series in a circuit having a polarity opposite to a polarity of a parallel circuit of the diode and the DC high-voltage generating circuit in the main switching circuit. Item 2. The AC / DC dual-purpose arc machining apparatus according to item 1.

The DC power source is a DC power source having three outputs of positive, zero, and negative, and the main switching circuit is connected to the positive and negative output terminals of the DC power source and the other end is commonly connected to a reactor and a switching element. Each of the reactors uses one of two reactor windings wound around a common iron core, and each of the reactor windings is connected in series with a common iron core. A reactor whose winding direction is set to a polarity that is magnetized in the same direction by a current that flows when the switching element is turned on, and between the common connection point of the series circuit and one of the load output terminals. A parallel circuit with the circuit is connected, the zero output terminal of the DC power supply is connected to the other load output terminal, and the DC high voltage generating circuit is connected between the load output terminals Universal arc processing apparatus according to Motomeko 1.

The DC power source is a DC power source having three outputs of positive, zero, and negative, and the main switching circuit is connected to the positive and negative output terminals of the DC power source and the other end is commonly connected to a reactor and a switching element. Each of the reactors uses one of two reactor windings wound around a common iron core, and each of the reactor windings is connected in series with a common iron core. A reactor whose winding direction is set to a polarity that is magnetized in the same direction by a current that flows when the switching element is turned on, and between the common connection point of the series circuit and one of the load output terminals. The parallel circuit of a circuit and the said DC high voltage generation circuit is connected, The zero output terminal of the said DC power supply and the other end of the said parallel circuit were made into the load output terminal. Of universal arc processing equipment.

The DC power source is a DC power source having three outputs of positive, zero, and negative, and the main switching circuit is connected to one of positive and negative of the DC power source and includes a reactor, a switching element, and the diode. And a second series circuit composed of a reactor connected to the other output terminal of the DC power supply and the sub-switching circuit, and the other ends of the first and second series circuits are connected in common The DC high-voltage generating circuit is connected between the load output terminals together with the zero output terminal of the DC power supply, and each reactor is composed of two reactor windings wound around a common iron core. Each of the reactor windings is a pole that magnetizes the shared iron core in the same direction by the current that flows when the switching elements connected in series are conducted. Universal arc processing apparatus according to claim 1 is a reactor winding direction is defined.

The DC power source is a DC power source having three outputs of positive, zero, and negative, and the main switching circuit is connected to one of positive and negative of the DC power source and includes a reactor, a switching element, and the diode. And a second series circuit composed of a reactor connected to the other output terminal of the DC power source and the sub-switching circuit, and the first and second series circuits are connected in common to each other. A load output terminal together with a zero output terminal of a DC power supply, the DC high voltage generating circuit is connected in parallel to the diode, and each of the reactors is one of two reactor windings wound around a common iron core Each reactor winding has a polarity in which the shared iron core is magnetized in the same direction by the current flowing when the switching elements connected in series are conducted. Universal arc processing apparatus according to claim 1 is a reactor which direction is defined.

The DC power source is a DC power source having three outputs of positive, zero, and negative, and the main switching circuit is connected to one of positive and negative of the DC power source and includes a reactor, a switching element, and the diode. And a second series circuit composed of a reactor connected to the other output terminal of the DC power source and the sub-switching circuit, and the first and second series circuits are connected in common to each other. A load output terminal together with a zero output terminal of the DC power supply, and the DC high voltage generation circuit is connected between a connection point of the diode and the switching element in the first series circuit and a zero output terminal of the DC power supply. And each reactor uses one of two reactor windings wound around a common core, and each reactor winding has a common core. Universal arc processing apparatus according to claim 1 by the current flowing during the conduction of switching devices connected in series is a reactor that winding direction is defined in the polarity magnetized in the same direction.

The DC power supply is a single DC power supply, and one reactor is connected in series to one of the output terminals of the DC power supply, and the main switching circuit is composed of four switching elements constituting a bridge circuit. 2. The AC / DC arc machining apparatus according to claim 1, wherein a DC terminal of the bridge circuit is connected to an output terminal of the DC power supply via the reactor, and an arc machining output is taken out from the AC terminal of the bridge circuit.

One reactor is connected to one of the output terminals of the DC power supply, the main switching circuit is composed of four switching elements constituting a bridge circuit, and one of the DC terminal side of the bridge circuit is connected to the reactor. The other end of the DC terminal of the bridge circuit is connected to the other output terminal of the DC power supply, and an output for arc machining is taken out from the AC terminal of the bridge circuit, and the DC high voltage generating circuit is connected to the load The diode is connected between output terminals, and the diode is connected in series in a circuit in the bridge circuit having a polarity that allows an output in the same direction as the output polarity of the DC high voltage generation circuit, and the sub-switching circuit is The said bridge circuit is connected in series in the circuit of the polarity opposite to the polarity to which the said diode is connected. Universal arc processing equipment.

One reactor is connected to one of the output terminals of the DC power supply, the main switching circuit is composed of four switching elements constituting a bridge circuit, and one of the DC terminal side of the bridge circuit is connected to the reactor. The other end of the DC terminal of the bridge circuit is connected to the other output terminal of the DC power supply, and the arc machining output is taken out from the AC terminal of the bridge circuit, and the DC high voltage generating circuit is connected to the diode. Is connected in series in a circuit having a polarity that allows the output in the same direction as the output polarity of the DC high-voltage generating circuit in the bridge circuit to be parallel, and the sub-switching circuit is the bridge circuit in the bridge circuit. The AC / DC arc machining apparatus according to claim 1, wherein the arc machining apparatus is connected in series in a circuit having a polarity opposite to a polarity to which the diode is connected.

One reactor is connected to one of the output terminals of the DC power supply, the main switching circuit is composed of four switching elements constituting a bridge circuit, and one of the DC terminal side of the bridge circuit is connected to the reactor. The other end of the DC terminal of the bridge circuit is connected to the other output terminal of the DC power supply, and the DC high voltage generating circuit is connected in parallel to the DC input terminal of the bridge circuit. The arc processing output is taken out from the AC terminal of the bridge circuit, and the sub-switching circuit arc-starts a circuit that supplies an output having a polarity opposite to the output of the DC high voltage generation circuit to the load. The AC / DC dual-purpose arc machining apparatus according to claim 1, which is inserted at a position where it is sometimes interrupted.

One of the output terminals of the DC power supply is connected in series with one reactor, a parallel circuit of the diode and the DC high-voltage generating circuit, and the main switching element has four bridge-connected switching elements. One side of the DC terminal side of the bridge connection is connected to one output terminal of the DC power source via the reactor and the parallel circuit, and the other end of the DC terminal of the bridge circuit is connected to the other side of the DC power source. The output for arc machining is taken out from the AC terminal of the bridge circuit, and the sub-switching circuit is loaded with an output having a polarity opposite to the output of the DC high voltage generation circuit in the bridge circuit. The AC / DC arc machining apparatus according to claim 1, wherein the circuit to be supplied is inserted at a position where the circuit to be interrupted is interrupted when the arc is started.

An auxiliary reactor is connected in series between the AC output terminal and the load output terminal of the bridge circuit, and each auxiliary reactor is one of two reactor windings wound around a common iron core. The AC / DC arc according to any one of claims 11 to 15, wherein each winding has a winding direction set to a polarity in which a common iron core is magnetized in the same direction by a current flowing through each winding. Processing equipment.

The DC high voltage generating circuit has a polarity for supplying a high voltage of reverse polarity to the arc machining load, and the control circuit starts the DC high voltage generating circuit at the time of arc start and outputs the main switching circuit to a reverse polarity output. After starting the arc, the output of the DC high voltage generation circuit is cut off and the sub switching circuit is turned on, and the main switching circuit is positive at the time of DC output and has a predetermined order at the time of AC output. The AC / DC arc machining apparatus according to any one of claims 1 to 16, which is a circuit that performs ON-OFF control at a point.

18. The circuit according to claim 1, wherein the main switching circuit is a circuit that switches a conduction period of a switching element that bears an output of each of the positive and reverse polarities constituting the switching circuit at the time of switching of the output polarity substantially without a gap. An AC / DC dual-purpose arc machining apparatus as described in 1.