JP3867414B2

JP3867414B2 - Polarity switching control method and consumable electrode arc welding power source

Info

Publication number: JP3867414B2
Application number: JP26742898A
Authority: JP
Inventors: 紀典本宮; 篤寛川本; 茂樹米森
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1997-09-20
Filing date: 1998-09-04
Publication date: 2007-01-10
Anticipated expiration: 2018-09-04
Also published as: JPH11156540A

Description

【０００１】
【発明の属する技術分野】
本発明は、消耗電極と母材との間に印加する溶接出力電圧の極性を逆極性と正極性とに交互に繰り返し切り換え、特に短絡を伴う消耗電極式アーク溶接における極性切換制御方法および消耗電極式アーク溶接電源に関する。
【０００２】
【従来の技術】
近年、消耗電極と母材との間に印加する電圧を逆極性と正極性とで交互に繰り返し切り換える消耗電極式アーク溶接電源は、短絡期間では極性を切り換えず、アーク期間で極性を切り換えるように制御している。
【０００３】
以下、従来の極性切換制御方法および消耗電極式アーク溶接電源について図面を参照しながら説明する。
【０００４】
図１１は従来の消耗電極式アーク溶接電源の構成を示すブロック図である。図１１において、１は入力交流電源、２は溶接出力部、３は第１スイッチング素子、４は第２スイッチング素子、５および６は出力端子、７は溶接電圧検出部、８は短絡・アーク判別部、９は極性比率指令部、１０は極性切換制御部である。
【０００５】
上記構成においてその動作を説明する。まず、極性比率指令部９により逆極性と正極性の比率が決定される。また、溶接電圧検出部７は、溶接出力電圧を検出する。つぎに、短絡・アーク判別部８は、溶接電圧検出部７の出力信号を入力して、その波形から消耗電極と母材とが短絡状態であるかアーク状態であるかを判別し、短絡期間とアーク期間とを示す信号を出力する。極性切換制御部１０は、極性比率指令部９の出力信号と短絡・アーク判別部８の出力信号とを入力し、短絡・アーク判別部８の出力信号によりアーク期間であって、極性比率指令部９の出力信号が逆極性を指令している場合には、第１スイッチング素子３をオン、第２スイッチング素子４をオフとし、溶接出力部２の出力する電圧を出力端子５と出力端子６との間に逆極性で供給し、また、短絡・アーク判別部８の出力信号によりアーク期間であって、極性比率指令部９の出力信号が正極性を指令している場合には、第１スイッチング素子３をオフ、第２スイッチング素子４をオンとし、溶接出力部２が出力する電圧を出力端子５と出力端子６との間に正極性で供給する。これにより、短絡期間中では極性の切り換えを行わず、アーク期間中に極性の切り換えを行っている。
【０００６】
【発明が解決しようとする課題】
このような従来の極性切換制御方法および消耗電極式アーク溶接電源では、短絡が開放してアークが再生した時点（以下、短絡開放アーク再生時点と称す）の直後付近で極性の切り換えが発生する場合があり、このタイミングで極性を切り換えると、アーク長が長くなっているためにアーク切れを発生し易くなり、溶接欠陥、ビード外観の不均一、スパッタ発生量の増加という問題点があった。
【０００７】
本発明は上記の課題を解決するもので、逆極性と正極性とを切り換えるときのアーク切れの発生を抑制できる極性切換制御方法および消耗電極式アーク溶接電源を提供することを目的とする。
【０００８】
【課題を解決するための手段】
請求項１に係わる本発明は、消耗電極と母材との間に印加する溶接出力電圧の極性を逆極性と正極性とに交互に繰り返し切り換える消耗電極式アーク溶接電源において、アーク期間中に極性を切り換える場合、所定の極性比率に対応する逆極性から正極性への切り換えが短絡開放アーク再生時点から第１の所定時間までの間に発生した場合には極性の切り換えを禁止して前記第１の所定時間を経過した時点で極性を切り換え、また、前記極性比率に対応する正極性から逆極性への切り換えが短絡開放アーク再生時点から第２の所定時間までの間に発生した場合には極性の切り換えを禁止して前記第２の所定時間を経過した時点で極性を切り換えるようにした極性切換制御方法である。
【０００９】
本発明により、アーク期間中に極性を切り換える場合において、短絡開放アーク再生時点直後近くにおける極性も切り換えが禁止され、アーク切れが抑制されて溶接欠陥、ビード外観の不均一、およびスパッタ発生量の増加を防止することができる。
【００１０】
また、消耗電極の溶融速度が正極性時のほうが速いため、アーク長が長くなり、アーク切れを起こし易い正極性から逆極性への切り換え時は、逆極性から正極性への切り換え時に比べ、極性の切り換えを禁止する時間を長く設定でき、アーク切れをより効果的に抑制できる。
【００１１】
請求項２に係わる本発明は、消耗電極と母材との間に印加する溶接出力電圧の極性を逆極性と正極性とに交互に繰り返し切り換える消耗電極式アーク溶接電源において、前記溶接出力電圧を検出する溶接電圧検出部と、検出された溶接出力電圧の波形から短絡期間とアーク期間とを判別する短絡・アーク判別部と、逆極性と正極性との所定の比率を指令する極性比率指令部と、短絡開放アーク再生時点から第１の所定時間を計測する第１計測回路部と、短絡開放アーク再生時点から第２の所定時間を計測する第２計測回路部と、前記極性比率指令部の出力信号と前記第１計測回路部の出力信号と前記第２計測回路部の出力信号とを入力して極性の切り換えを制御する極性切換制御部とを備え、前記極性切換制御部は前記極性比率指令部の出力信号によりアーク期間中に極性を切り換えるとき、逆極性から正極性への切り換えが前記第１計測回路部の計測中に発生した場合には極性の切り換えを禁止してその計測が終了した時点で極性を切り換え、また、正極性から逆極性への切り換えが前記第２計測回路部の計測中に発生した場合には極性の切り換えを禁止してその計測が終了した時点で極性を切り換えるようにした消耗電極式アーク溶接電源である。
【００１２】
本発明により、請求項１に係わる本発明と同じ作用と効果を得ることができる。
【００１３】
請求項３に係わる本発明は、消耗電極と母材との間に印加する溶接出力電圧の極性を逆極性と正極性とに交互に繰り返し切り換える消耗電極式アーク溶接電源において、前記溶接出力電圧を検出する溶接電圧検出部と、検出された溶接出力電圧の波形から短絡期間とアーク期間とを判別する短絡・アーク判別部と、逆極性と正極性との所定の比率を指令する極性比率指令部と、前記短絡・アーク判別部の出力信号を第１の所定時間だけ遅延させる第１遅延回路部と、前記短絡・アーク判別部の出力信号を第２の所定時間だけ遅延させる第２遅延回路部と、前記極性比率指令部の出力信号と前記第１遅延回路部の出力信号と前記第２遅延回路部の出力信号とを入力して極性の切り換えを制御する極性切換制御部とを備え、前記極性切換制御部は前記極性比率指令部の出力信号によりアーク期間中に極性を切り換えるとき、逆極性から正極性への切り換えが短絡開放アーク再生時点から前記第１の所定時間遅延した短絡期間中に発生した場合には極性の切り換えを禁止してその遅延した短絡期間の終了時点で極性を切り換え、また、正極性から逆極性への切り換えが短絡開放アーク再生時点から前記第２の所定時間遅延した短絡期間中に発生した場合には極性の切り換えを禁止してその遅延した短絡期間の終了時点で極性を切り換えるようにした消耗電極式アーク溶接電源である。
【００１４】
本発明により、請求項１および請求項２に係わる本発明と同じ作用と効果を得ることができる。
【００１５】
請求項４に係わる本発明は、消耗電極と母材との間に印加する溶接出力電圧の極性を逆極性と正極性とに交互に繰り返し切り換える消耗電極式アーク溶接電源において、短絡期間中における極性の切り換えを禁止するとともに、所定の極性比率に対応する逆極性から正極性への切り換えが短絡開放アーク再生時点から第１の所定時間までの間に発生した場合には極性の切り換えを禁止して前記第１の所定時間を経過した時点で極性を切り換え、また、前記極性比率に対応する正極性から逆極性への切り換えが短絡開放アーク再生時点から第２の所定時間までの間に発生した場合には極性の切り換えを禁止して前記第２の所定時間を経過した時点で極性を切り換えるようにした極性切換制御方法である。
【００１６】
本発明により、請求項１ないし請求項３に係わる本発明と同じ作用と効果を得ることができるとともに、従来の消耗電極式アーク溶接電源と同様に短絡期間中の極性切り換えも禁止することができる。
【００１７】
請求項５に係わる本発明は、消耗電極と母材との間に印加する溶接出力電圧の極性を逆極性と正極性とに交互に繰り返し切り換える消耗電極式アーク溶接電源において、前記溶接出力電圧を検出する溶接電圧検出部と、検出された溶接出力電圧の波形から短絡期間とアーク期間とを判別する短絡・アーク判別部と、逆極性と正極性との所定の比率を指令する極性比率指令部と、前記短絡・アーク判別部の出力信号を第１の所定時間だけ遅延させる第１遅延回路部と、前記短絡・アーク判別部の出力信号を第２の所定時間だけ遅延させる第２遅延回路部と、前記極性比率指令部の出力信号と前記短絡・アーク判別部の出力信号と前記第１遅延回路部の出力信号と前記第２遅延回路部の出力信号とを入力して極性の切り換えを制御する極性切換制御部とを備え、前記極性切換制御部は前記極性比率指令部の出力信号により極性を切り換えるとき、短絡期間中は極性の切り換えを禁止するとともに、前記極性比率に対応する逆極性から正極性への切り換えが短絡開放アーク再生時点から前記第１の所定時間遅延した短絡期間中に発生した場合には極性の切り換えを禁止してその遅延した短絡期間の終了時点で極性を切り換え、また、前記極性比率に対応する正極性から逆極性への切り換えが短絡開放アーク再生時点から前記第２の所定時間遅延した短絡期間中に発生した場合には極性の切り換えを禁止してその遅延した短絡期間の終了時点で極性を切り換えるようにした消耗電極式アーク溶接電源である。
【００１８】
本発明により、請求項４に係わる本発明と同じ作用と効果を得ることができる。
【００１９】
請求項６に係わる本発明は、消耗電極と母材との間に印加する溶接出力電圧の極性を逆極性と正極性とに交互に繰り返し切り換える消耗電極式アーク溶接電源において、前記溶接出力電圧を検出する溶接電圧検出部と、検出された溶接出力電圧の波形から短絡期間とアーク期間とを判別する短絡・アーク判別部と、前記短絡・アーク判別部の出力信号を第１の所定時間だけ遅延させる第１遅延回路部と、前記短絡・アーク判別部の出力信号を第２の所定時間だけ遅延させる第２遅延回路部と、前記極性比率指令部の出力信号と前記短絡・アーク判別部の出力信号と前記第１遅延回路部の出力信号と前記第２遅延回路部の出力信号とを入力して逆極性と正極性との所定の比率を指令する極性比率指令部と、前記極性比率指令部の出力信号を入力して極性の切り換えを制御する極性切換制御部とを備え、前記極性比率指令部は、所定の極性比率に応じた極性切り換えの出力信号を前記極性切換制御部へ出力して極性を切り換えるとき、短絡期間中は極性比率の時間カウントを禁止するとともに、逆極性の場合は短絡開放アーク再生時点から前記第１の所定時間遅延した短絡期間も極性比率の時間カウントを禁止し極性を切り換え、また、正極性の場合は短絡開放アーク再生時点から前記第２の所定時間遅延した短絡期間も極性比率の時間カウントを禁止し極性を切り換えるようにした消耗電極式アーク溶接電源である。
【００２０】
本発明により、請求項４ないし請求項５に係わる本発明と同じ作用と効果を得ることができるとともに、従来の消耗電極式アーク溶接電源と同様に短絡期間中の極性切り換えも禁止することができる。
【００２１】
【発明の実施の形態】
（実施の形態１）
以下、本発明の極性切換制御方法および消耗電極式アーク溶接電源の実施の形態１について図面を参照しながら説明する。本発明は請求項１および請求項２に係わる。
【００２２】
図１は本実施の形態の構成を示すブロック図である。なお、図１１に示した従来例と同じ構成要素には同一番号を付与して詳細な説明を省略する。図１において、１１ａは短絡開放アーク再生時点から第１の所定時間ｔ0 を計測する第１計測回路部、１１ｂは短絡開放アーク再生時点から第２の所定時間ｔ1 を計測する第２計測回路部である。本実施の形態が従来例と異なる点は、第１計測回路部１１ａと第２計測回路部１１ｂとを備え、極性比率に対応する極性の切り換えがアーク期間の先頭近傍で発生した場合には極性の切り換えを禁止したのち所定の時間を経過した時点でその極性の切り換えを実行するようにしたことにある。この場合の所定の時間を、逆極性から正極性への切り換えには第１の所定時間ｔ0 、正極性から逆極性への切り換えには第２の所定時間ｔ1 としている。
【００２３】
上記構成においてその動作を説明する。図２は、本実施の形態の動作を示す波形図である。図において、（ａ）は溶接電圧検出部７の出力信号（溶接出力電圧波形）、（ｂ）は短絡・アーク判別部８の出力信号、（ｃ）は第１計測回路部１１ａの出力信号、（ｄ）は第２計測回路部１１ｂの出力信号、（ｅ）は極性比率指令部９の出力信号、（ｆ）は極性切換制御部１０の出力信号を示す。
【００２４】
まず、溶接電圧検出部７は、溶接出力電圧を検出し（ａ）に示した信号を出力する。つぎに、短絡・アーク判別部８は、前記溶接電圧検出部７の出力信号を入力し、（ｂ）に示したように短絡期間ＳではＬレベル、アーク期間ＡではＨレベルの信号を出力する。また、第１計測回路部１１ａは、短絡・アーク判別部８の出力信号を入力し、（ｂ）に示した信号波形がＬレベルからＨレベルに変わった時点、すなわち短絡開放アーク再生時点を起点とし、第１の所定時間ｔ0 の間はＬレベルとなる（ｃ）に示した信号を出力し、第２計測回路部１１ｂは、短絡・アーク判別部８の出力信号を入力し、（ｂ）に示した信号波形がＬレベルからＨレベルに変わった時点、すなわち短絡開放アーク再生時点を起点とし、第２の所定時間ｔ1 の間はＬレベルとなる（ｄ）に示した信号を出力する。また、極性比率指令部９は、設定された所定の逆極性と正極性との比率に応じて、（ｅ）に示したように、逆極性の期間ではＨレベル、正極性の期間ではＬレベルとなる信号を出力する。
【００２５】
極性切換制御部１０は、極性比率指令部９の出力信号と第１計測回路部１１ａの出力信号と第２計測回路部１１ｂの出力信号とを入力し、第１計測回路部１１ａの出力信号がＬレベルの期間中、すなわち第１計測回路部１１ａが第１の所定時間ｔ0 を計測中に、極性比率指令部９の出力信号がＨレベルからＬレベルに変わった場合には直前のＨレベルを保持して出力し、第１の所定時間ｔ0 を計測終了した時点でＬレベルを出力する。また、第２計測回路部１１ｂの出力信号がＬレベルの期間中、すなわち第２計測回路部１１ｂが第２の所定時間ｔ1 を計測中に、極性比率指令部９の出力信号がＬレベルからＨレベルに変わった場合には直前のＬレベルを保持して出力し、第２の所定時間ｔ1 を計測終了した時点でＨレベルを出力する。
【００２６】
すなわち、極性切換制御部１０は、第１計測回路部１１ａの出力信号がＬレベルの期間では、極性比率指令部９の出力信号のＨレベルと、Ｈレベルから変わったＬレベルとに対して、第１スイッチング素子３をオン、第２スイッチング素子４をオフとし、溶接出力部２の出力する電圧を出力端子５と出力端子６との間に逆極性で供給し、また、第２計測回路部１１ｂの出力信号がＬレベルの期間では、極性比率指令部９の出力信号のＬレベルと、Ｌレベルから変わったＨレベルとに対して、第１スイッチング素子３をオフ、第２スイッチング素子４をオンとし、溶接出力部２の出力する電圧を出力端子５と出力端子６との間に正極性で供給している。
【００２７】
以上の動作により、逆極性から正極性に切り換える場合には短絡開放アーク再生時点から第１計測回路部１１ａが出力する第１の所定時間ｔ0 、また、正極性から逆極性に切り換える場合には短絡開放アーク再生時点から第２計測回路部１１ｂが出力する第２の所定時間ｔ1 の間は極性の切り換えが禁止され、前記所定時間を経過した時点で極性を切り換える。
【００２８】
以上のように本実施の形態によれば、アーク期間で極性を切り換える場合、逆極性から正極性への切り換えが短絡開放アーク再生時点から第１計測回路部１１ａが計測する第１の所定時間ｔ0 までの間に発生した場合は極性の切り換えを禁止して、第１の所定時間ｔ0 の計測を終了した時点で極性を切り換え、また、正極性から逆極性への切り換えが短絡開放アーク再生時点から第２計測回路部１１ｂが計測する第２の所定時間ｔ1 までの間に発生した場合は極性の切り換えを禁止して、第２の所定時間ｔ1 の計測を終了した時点で極性を切り換えるようにしたことにより、短絡開放アーク再生時点から第１の所定時間ｔ0 （逆極性から正極性への切り換え時）、または第２の所定時間ｔ1 （正極性から逆極性への切り換え時）までに発生した極性の切り換えが禁止され、アークに移行した直後における極性の切り換えでアークが消滅したり不安定になることを防止することができる。
【００２９】
（実施の形態２）
以下、本発明の極性切換制御方法および消耗電極式アーク溶接電源の実施の形態２について図面を参照しながら説明する。本発明は請求項１および請求項３に係わる。
【００３０】
図３は本実施の形態の構成を示すブロック図である。なお、実施の形態１で示した図１と同じ構成要素には同一番号を付与して詳細な説明を省略する。図において、１２ａは短絡・アーク判別部８の出力信号を第１の所定時間ｔ0 だけ遅延させて出力する第１遅延回路部、１２ｂは短絡・アーク判別部８の出力信号を第２の所定時間ｔ1 だけ遅延させて出力する第２遅延回路部である。また、図４は第１遅延回路部１２ａおよび第２遅延回路部１２ｂの構成例を示す回路図である。図に示したように、第１遅延回路部１２ａおよび第２遅延回路部１２ｂは、コンデンサと抵抗とで構成されている。本実施の形態が実施の形態１と異なる点は、第１計測回路部１１ａと第２計測回路部１１ｂとに代えて第１遅延回路部１２ａと第２遅延回路部１２ｂとを備え、実施の形態１と同様の動作をさせていることにある。
【００３１】
上記構成においてその動作を説明する。図５は、本実施の形態の動作を示す波形図である。図において、（ａ）は溶接電圧検出部７の出力信号（溶接出力電圧波形）、（ｂ）は短絡・アーク判別部８の出力信号、（ｃ）は第１遅延回路部１２ａの出力信号、（ｄ）は第２遅延回路部１２ｂの出力信号、（ｅ）は極性比率指令部９の出力信号、（ｆ）は極性切換制御部１０の出力信号を示す。
【００３２】
まず、溶接電圧検出部７は、溶接出力電圧を検出し（ａ）に示した信号を出力する。つぎに、短絡・アーク判別部８は、前記溶接電圧検出部７の出力信号を入力し、（ｂ）に示したように短絡期間ＳではＬレベル、アーク期間ＡではＨレベルの信号を出力する。また、第１遅延回路部１２ａは、短絡・アーク判別部８の出力信号を入力し、（ｂ）に示した信号を第１の所定時間ｔ0 だけ遅延させて（ｃ）に示した信号を出力し、第２遅延回路部１２ｂは、短絡・アーク判別部８の出力信号を入力し、（ｂ）に示した信号を第２の所定時間ｔ1 だけ遅延させて（ｄ）に示した信号を出力する。また、極性比率指令部９は、設定された所定の逆極性と正極性との比率に応じて、（ｅ）に示したように、逆極性の期間ではＨレベル、正極性の期間はＬレベルの信号を出力する。
【００３３】
極性切換制御部１０は、極性比率指令部９の出力信号と第１遅延回路部１２ａの出力信号と第２遅延回路部１２ｂの出力信号とを入力し、短絡開放アーク再生時点から第１遅延回路部１２ａの出力信号がＬレベルである期間中、すなわち短絡開放アーク再生時点から第１の所定時間ｔ0 だけ遅延された短絡期間中に、極性比率指令部９の出力信号がＨレベルからＬレベルに変わった場合には直前のＨレベルを保持して出力し、その遅延された短絡期間が終了した時点でＬレベルを出力する。また、短絡開放アーク再生時点から第２遅延回路部１２ｂの出力信号がＬレベルである期間中、すなわち短絡開放アーク再生時点から第２の所定時間ｔ1 だけ遅延された短絡期間中に、極性比率指令部９の出力信号がＬレベルからＨレベルに変わった場合には直前のＬレベルを保持して出力し、その遅延された短絡期間が終了した時点でＨレベルを出力する。
【００３４】
すなわち、極性切換制御部１０は、短絡開放アーク再生時点から第１遅延回路部１２ａの出力信号がＬレベルの期間では、極性比率指令部９の出力信号のＨレベルと、Ｈレベルから変わったＬレベルとに対して、第１スイッチング素子３をオン、第２スイッチング素子４をオフとし、溶接出力部２の出力する電圧を出力端子５と出力端子６との間に逆極性で供給し、また、短絡開放アーク再生時点から第２遅延回路部１２ｂの出力信号がＬレベルの期間では、極性比率指令部９の出力信号のＬレベルと、Ｌレベルから変わったＨレベルとに対して、第１スイッチング素子３をオフ、第２スイッチング素子４をオンとし、溶接出力部２の出力する電圧を出力端子５と出力端子６との間に正極性で供給している。
【００３５】
以上の動作により、逆極性から正極性に切り換える場合には短絡開放アーク再生時点から第１遅延回路部１２ａにより第１の所定時間ｔ0 だけ遅延された短絡期間中、また、正極性から逆極性に切り換える場合には短絡開放アーク再生時点から第２遅延回路部１２ｂにより第２の所定時間ｔ1 だけ遅延された短絡期間中は極性の切り換えが禁止され、前記遅延された短絡期間が終了した時点で極性を切り換える。
【００３６】
以上のように本実施の形態によれば、アーク期間で極性を切り換える場合、逆極性から正極性への切り換えが短絡開放アーク再生時点から第１遅延回路部１２ａにより第１の所定時間ｔ0 だけ遅延された短絡期間に発生した場合は極性の切り換えを禁止して、その遅延された短絡期間が終了した時点で極性を切り換え、また、正極性から逆極性への切り換えが短絡開放アーク再生時点から第２遅延回路部１２ｂにより第２の所定時間ｔ1 だけ遅延された短絡期間に発生した場合は極性の切り換えを禁止して、その遅延された短絡期間が終了した時点で極性を切り換えるようにしたことにより、実施の形態１と同様に、短絡開放アーク再生時点から第１の所定時間ｔ0 （逆極性から正極性への切り換え時）、または第２の所定時間ｔ1 （正極性から逆極性への切り換え時）までに発生した極性の切り換えが禁止され、アークに移行した直後における極性の切り換えでアークが消滅したり不安定になることを防止することができる。
【００３７】
（実施の形態３）
以下、本発明の極性切換制御方法および消耗電極式アーク溶接電源の実施の形態３について図面を参照しながら説明する。本発明は請求項４および請求項５に係わる。
【００３８】
図６は本実施の形態の構成を示すブロック図である。なお、実施の形態２で示した図３と同じ構成要素には同一番号を付与して詳細な説明を省略する。本実施の形態が実施の形態２と異なる点は、極性切換制御部１０が極性比率指令部９の出力信号と第１遅延回路部１２ａの出力信号と第２遅延回路部１２ｂの出力信号とを入力するとともに、短絡・アーク判別部８の出力信号も入力し、実施の形態１ないし実施の形態２と同様の切り換え禁止を実施するとともに、短絡期間Ｓにおける極性の切り換えも禁止するようにしたことにある。
【００３９】
上記構成においてその動作を説明する。図７は本実施の形態の動作を示す波形図である。図において、（ａ）は溶接電圧検出部７の出力信号（溶接出力電圧波形）、（ｂ）は短絡・アーク判別部８の出力信号、（ｃ）は第１遅延回路部１２ａの出力信号と短絡・アーク判別部８の出力信号との論理積（負論理の論理和）、（ｄ）は第２遅延回路部１２ｂの出力信号と短絡・アーク判別部８の出力信号との論理積（負論理の論理和）、（ｅ）は極性比率指令部９の出力信号、（ｆ）は極性切換制御部１０の出力信号を示す。
【００４０】
まず、溶接電圧検出部７は溶接出力電圧を検出し、（ａ）に示した信号を出力する。つぎに、短絡・アーク判別部８は溶接電圧検出部７の出力信号を入力し、（ｂ）に示したように短絡期間ＳではＬレベル、アーク期間ＡではＨレベルの信号を出力する。第１遅延回路部１２ａは、短絡・アーク判別部８の出力信号を入力し、第１の所定時間ｔ0 だけ遅らせた信号を出力し、第２遅延回路部１２ｂは、短絡・アーク判別部８の出力信号を入力し、第２の所定時間ｔ1 だけ遅らせた信号を出力する。また、極性比率指令部９は、設定された所定の逆極性と正極性の比率に応じて、（ｅ）に示したように、逆極性の期間はＨレベル、正極性の期間はＬレベルの信号を出力する。なお、（ｃ）と（ｄ）に示した論理積の信号は極性切換制御部１０の内部で生成される。
【００４１】
極性切換制御部１０は、極性比率指令部９の出力信号と第１遅延回路部１２ａの出力信号と第２遅延回路部１２ｂの出力信号と短絡・アーク判別部８の出力信号とを入力し、（ｂ）に示した短絡・アーク判別部８の出力信号がＬレベルである期間に発生した極性の切り換えは実行せず、また、短絡開放アーク再生時点から短絡・アーク判別部８の出力信号と第１遅延回路部１２ａの出力信号との論理積をとった（ｃ）の信号がＬレベルの間で極性比率指令部９の出力がＨレベルからＬレベルに変わった場合にはＬレベルになる直前のＨレベルを保持して出力し、（ｃ）の信号がＨレベルになった時点でＬレベルを出力する。また、短絡開放アーク再生時点から（ｂ）に示した短絡・アーク判別部８の出力信号と第２遅延回路部１２ｂの出力信号との論理積をとった（ｄ）の信号がＬレベルの間で極性比率指令部９の出力信号がＬレベルからＨレベルに変わった場合にはＨレベルになる直前のＬレベルを保持して出力し、（ｄ）の信号がＨレベルになった時点でＨレベルを出力する。
【００４２】
すなわち、極性切換制御部１０は、短絡・アーク判別部８の出力信号がＬレベルである期間と、短絡開放アーク再生時点から第１遅延回路部１２ａの出力信号がＬレベルの期間とでは、極性比率指令部９の出力信号のＨレベルと、Ｈレベルから変わったＬレベルとに対して、第１スイッチング素子３をオン、第２スイッチング素子４をオフとし、溶接出力部２の出力する電圧を出力端子５と出力端子６との間に逆極性で供給し、また、短絡・アーク判別部８の出力信号がＬレベルである期間と、短絡開放アーク再生時点から第２遅延回路部１２ｂの出力信号がＬレベルの期間とでは、極性比率指令部９の出力信号のＬレベルと、Ｌレベルから変わったＨレベルとに対して、第１スイッチング素子３をオフ、第２スイッチング素子４をオンとし、溶接出力部２の出力する電圧を出力端子５と出力端子６との間に正極性で供給している。
【００４３】
以上の動作により、短絡期間における極性の切り換えを禁止するとともに、実施の形態２で説明した動作を併せて実行することになる。
【００４４】
なお、図８は、第１遅延回路部１２ａおよび第２遅延回路部１２ｂの他の構成例を示す回路図である。図に示したように、コンデンサ、抵抗、およびダイオードで構成され、充電時定数を放電時定数よりも大きくして波形の立ち上がりにおける遅延を大きくし、立ち下がりにおける遅延を小さくすることにより、図７（ｃ）、図７（ｄ）に示した波形とほぼ同じ波形を論理積によらずに得ることが可能である。この場合には極性切換制御部１０における論理積処理を無用にすることができる。
【００４５】
以上のように本実施の形態によれば、極性切換制御部１０において極性比率指令部の出力信号と第１遅延回路部１２ａの出力信号と第２遅延回路部１２ｂの出力信号を入力するとともに短絡・アーク判別部の出力信号も入力し、短絡期間における極性の切り換えも禁止するようにしたことにより、実施の形態２と同様の効果を得るとともに、従来と同様に短絡期間では極性を切り換えないようにすることができる。
【００４６】
（実施の形態４）
以下、本発明の極性切換制御方法および消耗電極式アーク溶接電源の実施の形態４について図面を参照しながら説明する。本発明は請求項４および請求項６に係わる。
【００４７】
図９は本実施の形態の構成を示すブロック図である。なお、実施の形態３で示した図６と同じ構成要素には同一番号を付与して詳細な説明を省略する。本実施の形態が実施の形態３と異なる点は、極性比率指令部９が第１遅延回路部１２ａの出力信号と第２遅延回路部１２ｂの出力信号と短絡・アーク判別部８の出力信号とを入力し、実施の形態１ないし実施の形態２および実施の形態３と同様に切り換えを禁止するとともに、実施の形態３と同様に短絡期間Ｓにおける極性の切り換えも禁止するように比率を設定し、極性切換制御部１０は極性比率指令部９の上記設定通りの比率で極性を切り換えるようにしたことにある。
【００４８】
上記構成においてその動作を説明する。図１０は本実施の形態の動作を示す波形図である。図において、（ａ）は溶接電圧検出部７の出力信号（溶接出力電圧波形）、（ｂ）は短絡・アーク判別部８の出力信号、（ｃ）は第１遅延回路部１２ａの出力信号と短絡・アーク判別部８の出力信号との論理積（負論理の論理和）、（ｄ）は第２遅延回路部１２ｂの出力信号と短絡・アーク判別部８の出力信号との論理積（負論理の論理和）、（ｅ）は極性比率指令部９の出力信号を示す。
【００４９】
まず、溶接電圧検出部７は溶接出力電圧を検出し、（ａ）に示した信号を出力する。つぎに、短絡・アーク判別部８は溶接電圧検出部７の出力信号を入力し、（ｂ）に示したように短絡期間Ｓ（ｔn1、ｔn2、ｔp1、およびｔp2）ではＬレベル、アーク期間ＡではＨレベルの信号を出力する。第１遅延回路部１２ａは、短絡・アーク判別部８の出力信号を入力し、第１の所定時間ｔ0 だけ遅らせた信号を出力し、第２遅延回路部１２ｂは、短絡・アーク判別部８の出力信号を入力し、第２の所定時間ｔ1 だけ遅らせた信号を出力する。なお、（ｃ）および（ｄ）に示した論理積の信号は極性比率指令部９の内部で生成される。
【００５０】
極性比率指令部９は、第１遅延回路部１２ａの出力信号と第２遅延回路部１２ｂの出力信号と短絡・アーク判別部８の出力信号とを入力し、逆極性期間の場合は短絡・アーク判別部８の出力信号と第１遅延回路部１２ａの出力信号との論理積をとった（ｃ）の信号がＬレベルの間では極性比率の時間カウントを停止し、正極性期間の場合は短絡・アーク判別部８の出力信号と第２遅延回路部１２ｂの出力信号との論理積をとった（ｄ）の信号がＬレベルの間では極性比率の時間カウントを停止し、設定された所定の逆極性と正極性の極性比率に応じて、（ｅ）に示したように、逆極性の期間（ｔn＋ｔn1＋ｔ0）および（ｔn＋ｔn2＋ｔ0）ではＨレベル、正極性の期間（ｔp＋ｔp1＋ｔ1）および（ｔp＋ｔp2＋ｔ1）ではＬレベルの信号を出力する。このとき、所定の極性比率はｔn：ｔpである。
【００５１】
すなわち、極性比率指令部９は、所定の極性比率に対応した逆極性時間ｔn に、短絡・アーク判別部８の出力信号がＨレベルからＬレベルに変わった時点から第１遅延回路部１２ａの出力信号がＬレベルからＨレベルに変わるまでの時間（ｔn＋ｔ0）、または（ｔn2＋ｔ0）を加算した期間をＨレベルとして極性切換制御部１０に出力し、第１スイッチング素子３をオン、第２スイッチング素子４をオフとし、溶接出力部２の出力する電圧を出力端子５と出力端子６との間に逆極性で供給し、また、所定の極性比率に対応した正極性時間ｔp には、短絡・アーク判別部８の出力信号がＨレベルからＬレベルに変わった時点から第２遅延回路部１２ｂの出力信号がＬレベルからＨレベルに変わるまでの時間（ｔp1＋ｔ0）、または（ｔp2＋ｔ0）を加算した期間をＨレベルとして極性切換制御部１０に出力し、第１スイッチング素子３をオフ、第２スイッチング素子４をオンとし、溶接出力部２の出力する電圧を出力端子５と出力端子６との間に正極性で供給している。
【００５２】
以上の動作により、短絡期間Ｓにおける極性の切り換えを禁止するとともに、実施の形態３で説明した動作を併せて実行することになる。
【００５３】
なお、第１遅延回路部１２ａないし第２遅延回路部１２ｂは実施の形態３と同様に図８に示した構成とすることにより、図１０（ｃ）、図１０（ｄ）に示した波形とほぼ同じ波形を論理積によらずに得ることが可能である。この場合には極性比率指令部９における論理積処理を無用にすることができる。
【００５４】
以上のように本実施の形態によれば、極性比率指令部９において第１遅延回路部１２ａの出力信号と第２遅延回路部１２ｂの出力信号と短絡・アーク判別部８の出力信号を入力し、短絡期間Ｓにおける極性比率の時間カウントを停止するとともに、短絡開放アーク再生時点から逆極性では第１の所定時間ｔ0 の期間、正極性では第２の所定時間ｔ1 の期間も極性比率の時間カウントを禁止することにより、実施の形態３と同様の効果を得るとともに、従来例と同様に短絡期間Ｓで極性を切り換えないようにすることができる。
【００５５】
また、実施の形態１ないし実施の形態４における第１の所定時間ｔ0 および第２の所定時間ｔ1 は、溶接電流指令値、シールドガスの種類、消耗電極の種類に対応して可変としてもよい。
【００５６】
【発明の効果】
以上の説明から明らかなように、請求項１ないし請求項５に係わるいずれの本発明の極性切換制御方法および消耗電極式アーク溶接電源においても、短絡開放アーク再生時点から所定時間は極性の切り換えを禁止することにより、逆極性と正極性との極性切り換え時におけるアーク切れの発生を抑制することができ、また、請求項４ないし請求項６に係わる本発明の極性切換制御方法および消耗電極式アーク溶接電源では短絡期間中の極性切り換えも禁止することにより従来の極性切換制御方法と同様の安定な極性切り換えも可能となる。
【００５７】
そして、逆極性から正極性への切り換えと、正極性から逆極性への切り換えに対して、短絡開放アーク再生時点から極性の切り換えを禁止する時間を個々に設定することができるので、アーク長が長くなり、アーク切れを起こし易い正極性から逆極性への切り換え時は、逆極性から正極性への切り換え時に比べ、禁止時間を長く設定でき、アーク切れの発生をより効果的に抑制することができる。
【００５８】
さらに、極性切り換えを禁止する条件を溶接電流指令値、シールドガスの種類、消耗電極の種類に応じて決定することにより、溶接状態に対応した適切な極性切り換えでアーク切れの発生を抑制することもできる。
【図面の簡単な説明】
【図１】本発明の消耗電極式アーク溶接電源の実施の形態１の構成を示すブロック図
【図２】同実施の形態の動作を示す波形図
【図３】本発明の消耗電極式アーク溶接電源の実施の形態２の構成を示すブロック図
【図４】同実施の形態における第１遅延回路部および第２遅延回路部の構成を示す回路図
【図５】同実施の形態の動作を示す波形図
【図６】本発明の消耗電極式アーク溶接電源の実施の形態３の構成を示すブロック図
【図７】同実施の形態の動作を示す波形図
【図８】第１遅延回路部および第２遅延回路部の他の構成例を示す回路図
【図９】本発明の消耗電極式アーク溶接電源の実施の形態４の構成を示すブロック図
【図１０】同実施の形態の動作を示す波形図
【図１１】従来の消耗電極式アーク溶接電源の構成を示すブロック図
【符号の説明】
１入力交流電源
２溶接出力部
３第１スイッチング素子
４第２スイッチング素子
５，６出力端子
７溶接電圧検出部
８短絡・アーク判別部
９極性比率指令部
１０極性切換制御部
１１ａ第１計測回路部
１１ｂ第２計測回路部
１２ａ第１遅延回路部
１２ｂ第２遅延回路部
Ａアーク期間
Ｓ短絡期間
ｔ0 第１の所定時間
ｔ1 第２の所定時間
ｔn 所定の極性比率における逆極性時間
ｔp 所定の極性比率における正極性時間
ｔn1，ｔn2 逆極性期間における短絡時間
ｔp1，ｔp2 正極性期間における短絡時間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polarity switching control method and a consumable electrode in consumable electrode arc welding, particularly in a consumable electrode type arc welding, in which the polarity of the welding output voltage applied between the consumable electrode and the base material is repeatedly switched alternately between a reverse polarity and a positive polarity. The present invention relates to a type arc welding power source.
[0002]
[Prior art]
In recent years, a consumable electrode arc welding power source that alternately and repeatedly switches the voltage applied between the consumable electrode and the base material with reverse polarity and positive polarity does not switch the polarity during the short circuit period, but switches the polarity during the arc period. I have control.
[0003]
A conventional polarity switching control method and a consumable electrode arc welding power source will be described below with reference to the drawings.
[0004]
FIG. 11 is a block diagram showing a configuration of a conventional consumable electrode arc welding power source. In FIG. 11, 1 is an input AC power source, 2 is a welding output section, 3 is a first switching element, 4 is a second switching element, 5 and 6 are output terminals, 7 is a welding voltage detection section, and 8 is a short circuit / arc discrimination. , 9 is a polarity ratio command unit, and 10 is a polarity switching control unit.
[0005]
The operation of the above configuration will be described. First, the polarity ratio command unit 9 determines the ratio between reverse polarity and positive polarity. Moreover, the welding voltage detection part 7 detects a welding output voltage. Next, the short circuit / arc discriminating unit 8 inputs the output signal of the welding voltage detecting unit 7, discriminates whether the consumable electrode and the base material are in a short circuit state or an arc state from the waveform, and the short circuit period. And a signal indicating the arc period. The polarity switching control unit 10 inputs the output signal of the polarity ratio command unit 9 and the output signal of the short circuit / arc discrimination unit 8, and the arc period is determined by the output signal of the short circuit / arc discrimination unit 8. When the output signal 9 indicates a reverse polarity, the first switching element 3 is turned on, the second switching element 4 is turned off, and the voltage output from the welding output portion 2 is set to the output terminal 5 and the output terminal 6. The first switching is performed when the polarity is supplied in the reverse polarity and the arc period is determined by the output signal of the short circuit / arc discriminating unit 8 and the output signal of the polarity ratio command unit 9 commands the positive polarity. The element 3 is turned off, the second switching element 4 is turned on, and the voltage output from the welding output unit 2 is supplied between the output terminal 5 and the output terminal 6 with a positive polarity. Thus, the polarity is not switched during the short circuit period, but the polarity is switched during the arc period.
[0006]
[Problems to be solved by the invention]
In such a conventional polarity switching control method and consumable electrode type arc welding power source, when polarity switching occurs immediately after the short circuit is opened and the arc is regenerated (hereinafter referred to as the short circuit open arc regeneration time). If the polarity is switched at this timing, the arc length is long, so that arc breakage is likely to occur, and there are problems of welding defects, uneven bead appearance, and increased spatter generation.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a polarity switching control method and a consumable electrode type arc welding power source capable of suppressing the occurrence of arc breakage when switching between reverse polarity and positive polarity.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a consumable electrode type arc welding power source that alternately and repeatedly switches the polarity of the welding output voltage applied between the consumable electrode and the base material between the reverse polarity and the positive polarity. When switching from reverse polarity corresponding to a predetermined polarity ratio to positive polarity occurs between the time of short-circuit open arc regeneration and the first predetermined time, the switching of polarity is prohibited and the first is switched. When the predetermined time elapses, the polarity is switched, and when the switching from the positive polarity to the reverse polarity corresponding to the polarity ratio occurs between the short-circuit open arc regeneration time and the second predetermined time, the polarity is changed. Is switched so that the polarity is switched when the second predetermined time elapses.
[0009]
According to the present invention, when switching the polarity during the arc period, the switching of the polarity immediately after the short-circuit open arc regeneration is prohibited, the arc break is suppressed, welding defects, uneven bead appearance, and increased spatter generation Can be prevented.
[0010]
Also, since the melting rate of the consumable electrode is faster when the polarity is positive, the arc length becomes longer, and when switching from positive polarity to reverse polarity, where arc breakage is likely to occur, the polarity is greater than when switching from reverse polarity to positive polarity. It is possible to set a longer time for prohibiting the switching of the arc, and it is possible to more effectively suppress arc breakage.
[0011]
According to a second aspect of the present invention, there is provided a consumable electrode arc welding power source in which the polarity of the welding output voltage applied between the consumable electrode and the base material is alternately and repeatedly switched between a reverse polarity and a positive polarity. Welding voltage detection unit to detect, short-circuit / arc discrimination unit for discriminating short-circuit period and arc period from detected welding output voltage waveform, and polarity ratio command unit for commanding a predetermined ratio of reverse polarity and positive polarity A first measurement circuit unit that measures a first predetermined time from a short-circuit open arc regeneration time point, a second measurement circuit unit that measures a second predetermined time from a short-circuit open arc regeneration time point, and the polarity ratio command unit A polarity switching control unit for controlling polarity switching by inputting an output signal, an output signal of the first measurement circuit unit, and an output signal of the second measurement circuit unit, and the polarity switching control unit includes the polarity ratio Command unit output When switching the polarity during the arc period according to the signal, if switching from reverse polarity to positive polarity occurs during the measurement of the first measurement circuit unit, the polarity switching is prohibited and the polarity is completed when the measurement is completed. In addition, when switching from positive polarity to reverse polarity occurs during the measurement of the second measuring circuit unit, the switching of the polarity is prohibited and the polarity is switched when the measurement is completed. This is an electrode type arc welding power source.
[0012]
According to the present invention, the same operation and effect as the present invention according to claim 1 can be obtained.
[0013]
According to a third aspect of the present invention, there is provided a consumable electrode arc welding power source that alternately and repeatedly switches the polarity of the welding output voltage applied between the consumable electrode and the base material between a reverse polarity and a positive polarity. Welding voltage detection unit to detect, short-circuit / arc discrimination unit for discriminating short-circuit period and arc period from detected welding output voltage waveform, and polarity ratio command unit for commanding a predetermined ratio of reverse polarity and positive polarity A first delay circuit unit that delays the output signal of the short circuit / arc discrimination unit for a first predetermined time, and a second delay circuit unit that delays the output signal of the short circuit / arc discrimination unit for a second predetermined time A polarity switching control unit for controlling polarity switching by inputting an output signal of the polarity ratio command unit, an output signal of the first delay circuit unit, and an output signal of the second delay circuit unit, The polarity switching control unit When switching the polarity during the arc period by the output signal of the polarity ratio command unit, when switching from reverse polarity to positive polarity occurs during the short circuit period delayed for the first predetermined time from the short circuit open arc regeneration time point Polarity switching is prohibited and polarity is switched at the end of the delayed short circuit period, and switching from positive polarity to reverse polarity occurs during the short circuit period delayed by the second predetermined time from the short circuit open arc regeneration time point. In this case, it is a consumable electrode arc welding power source in which switching of the polarity is prohibited and the polarity is switched at the end of the delayed short-circuit period.
[0014]
According to the present invention, the same operation and effect as the present invention according to claims 1 and 2 can be obtained.
[0015]
According to a fourth aspect of the present invention, there is provided a consumable electrode arc welding power source that alternately and repeatedly switches the polarity of the welding output voltage applied between the consumable electrode and the base material between the reverse polarity and the positive polarity, and the polarity during the short circuit period. Switching is prohibited, and if switching from reverse polarity to positive polarity corresponding to a predetermined polarity ratio occurs between the time of short-circuit open arc regeneration and the first predetermined time, switching of polarity is prohibited. The polarity is switched when the first predetermined time has elapsed, and the switching from the positive polarity to the reverse polarity corresponding to the polarity ratio occurs between the short-circuit open arc regeneration time and the second predetermined time. Is a polarity switching control method in which polarity switching is prohibited and the polarity is switched when the second predetermined time has elapsed.
[0016]
According to the present invention, the same operation and effect as the present invention according to claims 1 to 3 can be obtained, and polarity switching during a short circuit period can be prohibited as in the conventional consumable electrode arc welding power source. .
[0017]
According to a fifth aspect of the present invention, there is provided a consumable electrode arc welding power source in which the polarity of the welding output voltage applied between the consumable electrode and the base material is alternately and repeatedly switched between a reverse polarity and a positive polarity. Welding voltage detection unit to detect, short-circuit / arc discrimination unit for discriminating short-circuit period and arc period from detected welding output voltage waveform, and polarity ratio command unit for commanding a predetermined ratio of reverse polarity and positive polarity A first delay circuit unit that delays the output signal of the short circuit / arc discrimination unit for a first predetermined time, and a second delay circuit unit that delays the output signal of the short circuit / arc discrimination unit for a second predetermined time And switching the polarity by inputting the output signal of the polarity ratio command unit, the output signal of the short-circuit / arc discrimination unit, the output signal of the first delay circuit unit, and the output signal of the second delay circuit unit Polarity switching system The polarity switching control unit prohibits switching of the polarity during a short circuit period and switches from the reverse polarity corresponding to the polarity ratio to the positive polarity when switching the polarity by the output signal of the polarity ratio command unit. When switching occurs during the short-circuit period delayed for the first predetermined time from the short-circuit open arc regeneration time, polarity switching is prohibited and the polarity is switched at the end of the delayed short-circuit period, and the polarity ratio When the switching from the positive polarity to the reverse polarity corresponding to is generated during the short-circuit period delayed by the second predetermined time from the short-circuit open arc regeneration time, the switching of the polarity is prohibited and the end point of the delayed short-circuit period This is a consumable electrode type arc welding power source in which the polarity is switched at
[0018]
According to the present invention, the same operation and effect as the present invention according to claim 4 can be obtained.
[0019]
According to a sixth aspect of the present invention, there is provided a consumable electrode arc welding power source that alternately and repeatedly switches the polarity of the welding output voltage applied between the consumable electrode and the base material between a reverse polarity and a positive polarity. A welding voltage detector for detecting, a short-circuit / arc discriminating unit for discriminating a short-circuit period and an arc period from the waveform of the detected welding output voltage, and an output signal of the short-circuit / arc discriminating unit being delayed by a first predetermined time A first delay circuit section for delaying, a second delay circuit section for delaying an output signal of the short-circuit / arc discrimination section for a second predetermined time, an output signal of the polarity ratio command section, and an output of the short-circuit / arc discrimination section A polarity ratio command unit that inputs a signal, an output signal of the first delay circuit unit, and an output signal of the second delay circuit unit and commands a predetermined ratio of reverse polarity and positive polarity; and the polarity ratio command unit Input the output signal of A polarity switching control unit that controls polarity switching, and the polarity ratio command unit outputs a polarity switching output signal corresponding to a predetermined polarity ratio to the polarity switching control unit to switch the polarity. During the period, the time ratio of the polarity ratio is prohibited, and in the case of the reverse polarity, the polarity ratio time count is also prohibited during the short-circuit period delayed from the time of the short-circuit open arc regeneration and the polarity is switched. In the case of the nature, it is a consumable electrode type arc welding power source which prohibits the time counting of the polarity ratio and switches the polarity during the short-circuit period delayed for the second predetermined time from the short-circuit open arc regeneration time point.
[0020]
According to the present invention, the same operation and effect as the present invention according to claims 4 to 5 can be obtained, and polarity switching during a short-circuit period can be prohibited as in the case of a conventional consumable electrode arc welding power source. .
[0021]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
Hereinafter, a first embodiment of a polarity switching control method and a consumable electrode type arc welding power source according to the present invention will be described with reference to the drawings. The present invention relates to claims 1 and 2.
[0022]
FIG. 1 is a block diagram showing the configuration of the present embodiment. The same constituent elements as those in the conventional example shown in FIG. In FIG. 1, 11a is a first measurement circuit unit for measuring a first predetermined time t0 from the time of short-circuit open arc regeneration, and 11b is a second measurement circuit unit for measuring a second predetermined time t1 from the time of short-circuit open arc regeneration. is there. The present embodiment is different from the conventional example in that the first measurement circuit unit 11a and the second measurement circuit unit 11b are provided, and the polarity is switched when the polarity switching corresponding to the polarity ratio occurs near the head of the arc period. The switching of the polarity is executed when a predetermined time elapses after the switching is prohibited. The predetermined time in this case is a first predetermined time t0 for switching from reverse polarity to positive polarity, and a second predetermined time t1 for switching from positive polarity to reverse polarity.
[0023]
The operation of the above configuration will be described. FIG. 2 is a waveform diagram showing the operation of the present embodiment. In the figure, (a) is an output signal (welding output voltage waveform) of the welding voltage detection unit 7, (b) is an output signal of the short-circuit / arc discrimination unit 8, (c) is an output signal of the first measurement circuit unit 11a, (D) shows the output signal of the second measurement circuit unit 11b, (e) shows the output signal of the polarity ratio command unit 9, and (f) shows the output signal of the polarity switching control unit 10.
[0024]
First, the welding voltage detector 7 detects the welding output voltage and outputs the signal shown in (a). Next, the short circuit / arc discriminating unit 8 inputs the output signal of the welding voltage detection unit 7 and outputs an L level signal in the short circuit period S and an H level signal in the arc period A as shown in FIG. . The first measurement circuit unit 11a receives the output signal of the short circuit / arc discriminating unit 8, and starts when the signal waveform shown in (b) changes from the L level to the H level, that is, the short circuit open arc regeneration time point. And the signal shown in (c), which is at the L level during the first predetermined time t0, is output, and the second measurement circuit unit 11b inputs the output signal of the short-circuit / arc discriminating unit 8, and (b) The signal shown in (d), which is at the L level during the second predetermined time t1, is output from the time when the signal waveform shown in FIG. In addition, the polarity ratio command unit 9 is configured so that, as shown in (e), H level in the reverse polarity period and L level in the positive period, according to the set ratio between the predetermined reverse polarity and positive polarity. Is output.
[0025]
The polarity switching control unit 10 inputs the output signal of the polarity ratio command unit 9, the output signal of the first measurement circuit unit 11a, and the output signal of the second measurement circuit unit 11b, and the output signal of the first measurement circuit unit 11a is If the output signal of the polarity ratio command unit 9 changes from the H level to the L level during the L level period, that is, while the first measurement circuit unit 11a is measuring the first predetermined time t0, the previous H level is set. The output is held and outputted, and the L level is outputted when the measurement of the first predetermined time t0 is completed. Further, during the period when the output signal of the second measurement circuit unit 11b is at L level, that is, while the second measurement circuit unit 11b is measuring the second predetermined time t1, the output signal of the polarity ratio command unit 9 is changed from L level to H level. When the level is changed, the previous L level is held and outputted, and the H level is outputted when the second predetermined time t1 is measured.
[0026]
That is, the polarity switching control unit 10 is configured such that the output signal of the polarity ratio command unit 9 and the L level changed from the H level during the period in which the output signal of the first measurement circuit unit 11a is at the L level. The first switching element 3 is turned on, the second switching element 4 is turned off, the voltage output from the welding output unit 2 is supplied between the output terminal 5 and the output terminal 6 in the reverse polarity, and the second measurement circuit unit In the period in which the output signal of 11b is at the L level, the first switching element 3 is turned off and the second switching element 4 is turned off for the L level of the output signal of the polarity ratio command unit 9 and the H level changed from the L level. The voltage output from the welding output section 2 is supplied between the output terminal 5 and the output terminal 6 with a positive polarity.
[0027]
With the above operation, when switching from reverse polarity to positive polarity, the first predetermined time t0 output from the first measurement circuit unit 11a from the time of short-circuit open arc regeneration, and when switching from positive polarity to reverse polarity, a short circuit occurs. The switching of the polarity is prohibited during the second predetermined time t1 output from the second measuring circuit unit 11b from the open arc regeneration time point, and the polarity is switched when the predetermined time elapses.
[0028]
As described above, according to the present embodiment, when switching the polarity in the arc period, the switching from the reverse polarity to the positive polarity is the first predetermined time t0 measured by the first measurement circuit unit 11a from the short-circuit open arc regeneration time point. If this occurs, the switching of the polarity is prohibited, the polarity is switched when the measurement of the first predetermined time t0 is completed, and the switching from the positive polarity to the reverse polarity is started from the time of the short-circuit open arc regeneration. When it occurs before the second predetermined time t1 measured by the second measurement circuit unit 11b, the polarity switching is prohibited and the polarity is switched when the measurement of the second predetermined time t1 is finished. As a result, the poles generated from the time of short-circuit open arc regeneration to the first predetermined time t0 (when switching from reverse polarity to positive polarity) or the second predetermined time t1 (when switching from positive polarity to reverse polarity) Switching is prohibited, arc polarity switching immediately after the transition to the arc can be prevented from being unstable or disappear.
[0029]
(Embodiment 2)
Hereinafter, a second embodiment of the polarity switching control method and the consumable electrode type arc welding power source of the present invention will be described with reference to the drawings. The present invention relates to claims 1 and 3.
[0030]
FIG. 3 is a block diagram showing the configuration of the present embodiment. The same constituent elements as those shown in FIG. 1 shown in the first embodiment are given the same reference numerals, and detailed description thereof is omitted. In the figure, 12a is a first delay circuit section for outputting the output signal of the short-circuit / arc discriminating section 8 after being delayed by a first predetermined time t0, and 12b is an output signal of the short-circuit / arc discriminating section 8 for a second predetermined time. This is a second delay circuit section that outputs a signal delayed by t1. FIG. 4 is a circuit diagram showing a configuration example of the first delay circuit unit 12a and the second delay circuit unit 12b. As shown in the figure, the first delay circuit unit 12a and the second delay circuit unit 12b are composed of capacitors and resistors. The present embodiment is different from the first embodiment in that a first delay circuit unit 12a and a second delay circuit unit 12b are provided instead of the first measurement circuit unit 11a and the second measurement circuit unit 11b. The operation is the same as in the first mode.
[0031]
The operation of the above configuration will be described. FIG. 5 is a waveform diagram showing the operation of the present embodiment. In the figure, (a) is an output signal (welding output voltage waveform) of the welding voltage detector 7, (b) is an output signal of the short-circuit / arc discriminator 8, (c) is an output signal of the first delay circuit unit 12a, (D) shows the output signal of the second delay circuit unit 12b, (e) shows the output signal of the polarity ratio command unit 9, and (f) shows the output signal of the polarity switching control unit 10.
[0032]
First, the welding voltage detector 7 detects the welding output voltage and outputs the signal shown in (a). Next, the short circuit / arc discriminating unit 8 inputs the output signal of the welding voltage detection unit 7 and outputs an L level signal in the short circuit period S and an H level signal in the arc period A as shown in FIG. . The first delay circuit unit 12a receives the output signal of the short-circuit / arc determination unit 8, delays the signal shown in (b) by a first predetermined time t0, and outputs the signal shown in (c). The second delay circuit unit 12b receives the output signal of the short-circuit / arc discriminating unit 8, delays the signal shown in (b) by a second predetermined time t1, and outputs the signal shown in (d). To do. In addition, the polarity ratio command unit 9 determines that the ratio between the predetermined reverse polarity and the positive polarity is H level during the reverse polarity period and L level during the positive polarity period, as shown in (e). The signal is output.
[0033]
The polarity switching control unit 10 inputs the output signal of the polarity ratio command unit 9, the output signal of the first delay circuit unit 12a, and the output signal of the second delay circuit unit 12b, and the first delay circuit from the time of short-circuit open arc regeneration. The output signal of the polarity ratio command unit 9 changes from the H level to the L level during the period when the output signal of the unit 12a is at the L level, that is, during the short circuit period delayed by the first predetermined time t0 from the short-circuit open arc regeneration time point. When changed, the previous H level is held and outputted, and the L level is outputted when the delayed short-circuit period ends. In addition, during the period when the output signal of the second delay circuit unit 12b is at L level from the short-circuit open arc regeneration time point, that is, during the short-circuit period delayed by the second predetermined time t1 from the short-circuit open arc regeneration time point. When the output signal of the unit 9 changes from the L level to the H level, the previous L level is held and outputted, and the H level is outputted when the delayed short-circuit period ends.
[0034]
In other words, the polarity switching control unit 10 outputs the H level of the output signal of the polarity ratio command unit 9 and the L level changed from the H level during the period in which the output signal of the first delay circuit unit 12a is at the L level from the time of short-circuit open arc regeneration. With respect to the level, the first switching element 3 is turned on, the second switching element 4 is turned off, and the voltage output from the welding output portion 2 is supplied between the output terminal 5 and the output terminal 6 with a reverse polarity. In the period in which the output signal of the second delay circuit unit 12b is at the L level from the time of the short-circuit open arc regeneration, the first is applied to the L level of the output signal of the polarity ratio command unit 9 and the H level changed from the L level. The switching element 3 is turned off, the second switching element 4 is turned on, and the voltage output from the welding output portion 2 is supplied between the output terminal 5 and the output terminal 6 with a positive polarity.
[0035]
With the above operation, when switching from reverse polarity to positive polarity, during the short-circuit period delayed by the first delay circuit unit 12a from the time of short-circuit open arc regeneration by the first predetermined time t0, or from positive polarity to reverse polarity. In the case of switching, polarity switching is prohibited during the short-circuit period delayed by the second predetermined delay time t1 by the second delay circuit section 12b from the time of short-circuit open arc regeneration, and the polarity is reached when the delayed short-circuit period ends. Switch.
[0036]
As described above, according to the present embodiment, when the polarity is switched in the arc period, the switching from the reverse polarity to the positive polarity is delayed by the first predetermined time t0 by the first delay circuit unit 12a from the time of the short-circuit open arc regeneration. If this occurs during the short-circuit period, the polarity switching is prohibited, the polarity is switched when the delayed short-circuit period ends, and the switching from the positive polarity to the reverse polarity is performed from the time of the short-circuit open arc regeneration. 2) When it occurs in the short circuit period delayed by the second predetermined time t1 by the delay circuit unit 12b, the polarity switching is prohibited, and the polarity is switched when the delayed short circuit period ends. As in the first embodiment, the first predetermined time t0 (when switching from reverse polarity to positive polarity) or the second predetermined time t1 (whether positive polarity is detected) from the time of short-circuit open arc regeneration. Switching polarity generated by the time switching) in the opposite polarity is prohibited, arc polarity switching immediately after the transition to the arc can be prevented from being unstable or disappear.
[0037]
(Embodiment 3)
Hereinafter, a polarity switching control method and a consumable electrode type arc welding power source according to a third embodiment of the present invention will be described with reference to the drawings. The present invention relates to claims 4 and 5.
[0038]
FIG. 6 is a block diagram showing the configuration of the present embodiment. Note that the same components as those in FIG. 3 shown in the second embodiment are given the same reference numerals, and detailed description thereof is omitted. The difference between the present embodiment and the second embodiment is that the polarity switching control unit 10 determines the output signal of the polarity ratio command unit 9, the output signal of the first delay circuit unit 12a, and the output signal of the second delay circuit unit 12b. In addition to the input, the output signal of the short-circuit / arc discriminating unit 8 is also input to prohibit the switching in the same manner as in the first and second embodiments and to prohibit the switching of the polarity in the short-circuit period S. It is in.
[0039]
The operation of the above configuration will be described. FIG. 7 is a waveform diagram showing the operation of the present embodiment. In the figure, (a) is an output signal (welding output voltage waveform) of the welding voltage detection unit 7, (b) is an output signal of the short-circuit / arc discrimination unit 8, and (c) is an output signal of the first delay circuit unit 12a. The logical product (logical OR of negative logic) with the output signal of the short circuit / arc discriminating unit 8, (d) is the logical product (negative) of the output signal of the second delay circuit unit 12 b and the output signal of the short circuit / arc discriminating unit 8. (Logical OR), (e) shows the output signal of the polarity ratio command unit 9, and (f) shows the output signal of the polarity switching control unit 10.
[0040]
First, the welding voltage detection part 7 detects a welding output voltage, and outputs the signal shown to (a). Next, the short-circuit / arc discriminating unit 8 inputs the output signal of the welding voltage detection unit 7 and outputs an L-level signal in the short-circuit period S and an H-level signal in the arc period A as shown in FIG. The first delay circuit unit 12a receives the output signal of the short circuit / arc discriminating unit 8 and outputs a signal delayed by the first predetermined time t0. The second delay circuit unit 12b An output signal is input, and a signal delayed by a second predetermined time t1 is output. In addition, the polarity ratio command unit 9 sets the H level during the reverse polarity period and the L level during the positive period, as shown in (e), according to the set ratio of the reverse polarity and positive polarity. Output a signal. The logical product signals shown in (c) and (d) are generated inside the polarity switching control unit 10.
[0041]
The polarity switching control unit 10 inputs the output signal of the polarity ratio command unit 9, the output signal of the first delay circuit unit 12a, the output signal of the second delay circuit unit 12b, and the output signal of the short-circuit / arc discrimination unit 8, The switching of the polarity that occurred during the period when the output signal of the short-circuit / arc discriminating unit 8 shown in (b) is at the L level is not executed, and the output signal of the short-circuit / arc discriminating unit 8 is When the output of the polarity ratio command unit 9 changes from the H level to the L level while the signal (c) obtained by ANDing with the output signal of the first delay circuit unit 12a is at the L level, the signal becomes the L level. The previous H level is held and outputted, and the L level is outputted when the signal (c) becomes H level. In addition, the signal of (d) obtained by taking the logical product of the output signal of the short-circuit / arc discriminating unit 8 and the output signal of the second delay circuit unit 12b shown in (b) from the time of short-circuit open arc regeneration is between L level. When the output signal of the polarity ratio command unit 9 changes from the L level to the H level, the L level immediately before becoming the H level is held and outputted, and when the signal (d) becomes the H level, Output level.
[0042]
That is, the polarity switching control unit 10 determines the polarity between the period in which the output signal of the short circuit / arc discriminating unit 8 is at the L level and the period in which the output signal of the first delay circuit unit 12a is at the L level from the time of short circuit open arc regeneration. For the H level of the output signal of the ratio command unit 9 and the L level changed from the H level, the first switching element 3 is turned on, the second switching element 4 is turned off, and the voltage output from the welding output unit 2 is The output is supplied with the opposite polarity between the output terminal 5 and the output terminal 6, and the output of the second delay circuit unit 12b from the period when the output signal of the short circuit / arc discriminating unit 8 is at the L level and the short circuit open arc regeneration point. In the period when the signal is at the L level, the first switching element 3 is turned off and the second switching element 4 is turned on with respect to the L level of the output signal of the polarity ratio command unit 9 and the H level changed from the L level. And supplies a positive polarity between the voltage outputted from the welding output portion 2 and the output terminal 5 and the output terminal 6.
[0043]
With the above operation, switching of the polarity during the short circuit period is prohibited, and the operation described in the second embodiment is also executed.
[0044]
FIG. 8 is a circuit diagram showing another configuration example of the first delay circuit unit 12a and the second delay circuit unit 12b. As shown in FIG. 7, the capacitor is composed of a capacitor, a resistor, and a diode, and the charging time constant is made larger than the discharging time constant to increase the delay at the rising edge of the waveform and reduce the delay at the falling edge. (C) It is possible to obtain a waveform substantially the same as the waveform shown in FIG. In this case, the logical product processing in the polarity switching control unit 10 can be made unnecessary.
[0045]
As described above, according to the present embodiment, the polarity switching control unit 10 inputs the output signal of the polarity ratio command unit, the output signal of the first delay circuit unit 12a, and the output signal of the second delay circuit unit 12b and short-circuits. -By inputting the output signal of the arc discriminating unit and prohibiting the switching of the polarity during the short-circuit period, the same effect as in the second embodiment is obtained, and the polarity is not switched during the short-circuit period as in the conventional case. Can be.
[0046]
(Embodiment 4)
Hereinafter, a polarity switching control method and a consumable electrode type arc welding power source according to a fourth embodiment of the present invention will be described with reference to the drawings. The present invention relates to claims 4 and 6.
[0047]
FIG. 9 is a block diagram showing the configuration of the present embodiment. It should be noted that the same components as those in FIG. 6 shown in the third embodiment are given the same numbers, and detailed description thereof is omitted. This embodiment is different from the third embodiment in that the polarity ratio command unit 9 outputs an output signal from the first delay circuit unit 12a, an output signal from the second delay circuit unit 12b, and an output signal from the short circuit / arc discrimination unit 8. And the ratio is set so that the switching is prohibited as in the first to second embodiments and the third embodiment, and the switching of the polarity in the short-circuit period S is also prohibited as in the third embodiment. The polarity switching control unit 10 switches the polarity at the ratio as set by the polarity ratio command unit 9.
[0048]
The operation of the above configuration will be described. FIG. 10 is a waveform diagram showing the operation of the present embodiment. In the figure, (a) is an output signal (welding output voltage waveform) of the welding voltage detection unit 7, (b) is an output signal of the short-circuit / arc discrimination unit 8, and (c) is an output signal of the first delay circuit unit 12a. The logical product (logical OR of negative logic) with the output signal of the short circuit / arc discriminating unit 8, (d) is the logical product (negative) of the output signal of the second delay circuit unit 12 b and the output signal of the short circuit / arc discriminating unit 8. (Logical OR) and (e) indicate output signals of the polarity ratio command unit 9.
[0049]
First, the welding voltage detection part 7 detects a welding output voltage, and outputs the signal shown to (a). Next, the short-circuit / arc discriminating unit 8 inputs the output signal of the welding voltage detection unit 7 and, as shown in (b), in the short-circuit period S (tn1, tn2, tp1, and tp2), the L level and the arc period A Then, an H level signal is output. The first delay circuit unit 12a receives the output signal of the short circuit / arc discriminating unit 8 and outputs a signal delayed by the first predetermined time t0. The second delay circuit unit 12b An output signal is input, and a signal delayed by a second predetermined time t1 is output. The logical product signals shown in (c) and (d) are generated inside the polarity ratio command unit 9.
[0050]
The polarity ratio command unit 9 inputs the output signal of the first delay circuit unit 12a, the output signal of the second delay circuit unit 12b, and the output signal of the short circuit / arc discriminating unit 8, and in the case of the reverse polarity period, the short circuit / arc When the signal of (c) obtained by ANDing the output signal of the discriminating unit 8 and the output signal of the first delay circuit unit 12a is L level, the time counting of the polarity ratio is stopped, and in the case of the positive polarity period, the short circuit is performed. When the signal of (d) obtained by ANDing the output signal of the arc discriminating unit 8 and the output signal of the second delay circuit unit 12b is L level, the time counting of the polarity ratio is stopped and the predetermined predetermined value is set. Depending on the polarity ratio between the reverse polarity and the positive polarity, as shown in (e), it is H level during the reverse polarity period (tn + tn1 + t0) and (tn + tn2 + t0), and L level during the positive polarity period (tp + tp1 + t1) and (tp + tp2 + t1). The signal is output. At this time, the predetermined polarity ratio is tn: tp.
[0051]
That is, the polarity ratio command unit 9 outputs the output of the first delay circuit unit 12a from the time when the output signal of the short circuit / arc discriminating unit 8 changes from the H level to the L level at the reverse polarity time tn corresponding to the predetermined polarity ratio. A time obtained by adding the time (tn + t0) or (tn2 + t0) until the signal changes from the L level to the H level is output to the polarity switching control unit 10 as the H level, the first switching element 3 is turned on, and the second switching element 4 is turned on. Is turned off, the voltage output from the welding output section 2 is supplied between the output terminal 5 and the output terminal 6 with the opposite polarity, and at the positive polarity time tp corresponding to a predetermined polarity ratio, a short circuit / arc discrimination is performed. The time (tp1 + t0) or (tp2 + t0) from when the output signal of the unit 8 changes from H level to L level until the output signal of the second delay circuit unit 12b changes from L level to H level is added Is output to the polarity switching control unit 10 as the H level, the first switching element 3 is turned off, the second switching element 4 is turned on, and the voltage output from the welding output unit 2 is output between the output terminal 5 and the output terminal 6. It is supplied with positive polarity.
[0052]
With the above operation, switching of the polarity in the short-circuit period S is prohibited, and the operation described in the third embodiment is also executed.
[0053]
The first delay circuit unit 12a to the second delay circuit unit 12b are configured as shown in FIG. 8 as in the third embodiment, so that the waveforms shown in FIG. 10 (c) and FIG. It is possible to obtain almost the same waveform without using logical product. In this case, the logical product processing in the polarity ratio command unit 9 can be made unnecessary.
[0054]
As described above, according to the present embodiment, the polarity ratio command unit 9 inputs the output signal of the first delay circuit unit 12a, the output signal of the second delay circuit unit 12b, and the output signal of the short-circuit / arc discrimination unit 8. In addition, the time count of the polarity ratio in the short-circuit period S is stopped, and the time ratio of the polarity ratio is also counted for the first predetermined time t0 for the reverse polarity and the second predetermined time t1 for the positive polarity from the short-circuit open arc regeneration time point. By prohibiting the above, it is possible to obtain the same effect as in the third embodiment and not to switch the polarity in the short-circuit period S as in the conventional example.
[0055]
Further, the first predetermined time t0 and the second predetermined time t1 in the first to fourth embodiments may be variable corresponding to the welding current command value, the type of shield gas, and the type of consumable electrode.
[0056]
【The invention's effect】
As is clear from the above description, in any of the polarity switching control methods and the consumable electrode type arc welding power source according to any one of the first to fifth aspects of the present invention, the polarity is switched for a predetermined time from the time of short-circuit open arc regeneration. By prohibiting, it is possible to suppress the occurrence of arc break at the time of polarity switching between the reverse polarity and the positive polarity, and the polarity switching control method and the consumable electrode type arc of the present invention according to claims 4 to 6. By prohibiting polarity switching during the short-circuit period in the welding power source, stable polarity switching similar to the conventional polarity switching control method can be performed.
[0057]
In addition, for switching from reverse polarity to positive polarity and switching from positive polarity to reverse polarity, the time for which switching of polarity is prohibited from the time of short-circuit open arc regeneration can be individually set. When switching from positive polarity to reverse polarity, which tends to cause arc breakage, the prohibition time can be set longer than when switching from reverse polarity to positive polarity, and the occurrence of arc breakage can be suppressed more effectively. it can.
[0058]
Furthermore, by determining the conditions for prohibiting polarity switching according to the welding current command value, the type of shield gas, and the type of consumable electrode, it is also possible to suppress the occurrence of arc breaks with appropriate polarity switching corresponding to the welding state. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a consumable electrode type arc welding power source according to a first embodiment of the present invention.
FIG. 2 is a waveform diagram showing the operation of the embodiment
FIG. 3 is a block diagram showing a configuration of a consumable electrode type arc welding power source according to a second embodiment of the present invention.
FIG. 4 is a circuit diagram showing a configuration of a first delay circuit unit and a second delay circuit unit in the same embodiment;
FIG. 5 is a waveform diagram showing the operation of the embodiment;
FIG. 6 is a block diagram showing the configuration of Embodiment 3 of the consumable electrode arc welding power source according to the present invention.
FIG. 7 is a waveform diagram showing the operation of the embodiment
FIG. 8 is a circuit diagram showing another configuration example of the first delay circuit unit and the second delay circuit unit;
FIG. 9 is a block diagram showing a configuration of a consumable electrode type arc welding power source according to a fourth embodiment of the present invention.
FIG. 10 is a waveform diagram showing the operation of the embodiment.
FIG. 11 is a block diagram showing a configuration of a conventional consumable electrode type arc welding power source.
[Explanation of symbols]
1 input AC power supply
2 Welding output
3 First switching element
4 Second switching element
5,6 Output terminal
7 Welding voltage detector
8 Short-circuit / arc discriminator
9 Polarity ratio command section
10 Polarity switching controller
11a First measurement circuit section
11b Second measurement circuit section
12a First delay circuit section
12b Second delay circuit section
A Arc period
S Short-circuit period
t0 First predetermined time
t1 Second predetermined time
tn Reverse polarity time at a given polarity ratio
tp Positive polarity time at a given polarity ratio
tn1, tn2 Short circuit time in reverse polarity period
tp1, tp2 Short circuit time during positive polarity period

Claims

In a consumable electrode arc welding power source that switches the polarity of the welding output voltage applied between the consumable electrode and the base metal alternately between reverse polarity and positive polarity, when switching the polarity during the arc period, the polarity ratio is When switching from the corresponding reverse polarity to positive polarity occurs between the time of short-circuit open arc regeneration and the first predetermined time, the polarity switching is prohibited and the polarity is reached when the first predetermined time elapses. In addition, when the switching from the positive polarity corresponding to the polarity ratio to the reverse polarity occurs between the time of the short-circuit open arc regeneration and the second predetermined time, the switching of the polarity is prohibited. A polarity switching control method in which the polarity is switched when a predetermined time elapses.

In a consumable electrode arc welding power source that alternately and repeatedly switches the polarity of the welding output voltage applied between the consumable electrode and the base material between a reverse polarity and a positive polarity, a welding voltage detection unit that detects the welding output voltage, and a detection A short-circuit / arc discriminating unit that discriminates a short-circuit period and an arc period from the waveform of the welding output voltage, a polarity ratio command unit that commands a predetermined ratio of reverse polarity and positive polarity, A first measurement circuit unit that measures a predetermined time of 1, a second measurement circuit unit that measures a second predetermined time from the time of short-circuit open arc regeneration, an output signal of the polarity ratio command unit, and the first measurement circuit unit And a polarity switching control unit that controls the switching of the polarity by inputting the output signal of the second measurement circuit unit and the polarity switching control unit during the arc period according to the output signal of the polarity ratio command unit Extreme When switching from reverse polarity to positive polarity occurs during the measurement of the first measurement circuit unit, switching of the polarity is prohibited and the polarity is switched when the measurement is completed. A consumable electrode arc welding power source which switches polarity when the switching from reverse polarity to reverse polarity occurs during the measurement of the second measurement circuit section and switches the polarity when the measurement is completed.

In a consumable electrode arc welding power source that alternately and repeatedly switches the polarity of the welding output voltage applied between the consumable electrode and the base material between a reverse polarity and a positive polarity, a welding voltage detection unit that detects the welding output voltage, and a detection A short-circuit / arc discriminating unit that discriminates a short-circuit period and an arc period from the waveform of the welding output voltage, a polarity ratio command unit that commands a predetermined ratio of reverse polarity and positive polarity, and the short-circuit / arc discriminating unit A first delay circuit section that delays the output signal by a first predetermined time; a second delay circuit section that delays the output signal of the short-circuit / arc discrimination section by a second predetermined time; and an output of the polarity ratio command section A polarity switching control unit that inputs a signal, an output signal of the first delay circuit unit, and an output signal of the second delay circuit unit to control polarity switching, and the polarity switching control unit includes the polarity ratio command Output signal When switching the polarity during the arc period, if the switching from reverse polarity to positive polarity occurs during the short circuit period delayed for the first predetermined time from the short circuit open arc regeneration time, the polarity switching is prohibited. The polarity is switched at the end of the delayed short-circuit period, and the polarity is switched when the switching from the positive polarity to the reverse polarity occurs during the short-circuit period delayed by the second predetermined time from the short-circuit open arc regeneration time. A consumable electrode arc welding power supply that is prohibited and switches polarity at the end of the delayed short circuit period.

In a consumable electrode arc welding power supply that alternately and repeatedly switches the polarity of the welding output voltage applied between the consumable electrode and the base material between the reverse polarity and the positive polarity, the polarity switching during the short-circuit period is prohibited, When switching from reverse polarity corresponding to the polarity ratio to positive polarity occurs between the time of short-circuit open arc regeneration and the first predetermined time, the switching of polarity is prohibited and the first predetermined time has elapsed. The polarity is switched at the time, and if switching from the positive polarity to the reverse polarity corresponding to the polarity ratio occurs between the short-circuit open arc regeneration time and the second predetermined time, the polarity switching is prohibited. A polarity switching control method in which the polarity is switched when the second predetermined time has elapsed.

In a consumable electrode arc welding power source that alternately and repeatedly switches the polarity of the welding output voltage applied between the consumable electrode and the base material between a reverse polarity and a positive polarity, a welding voltage detection unit that detects the welding output voltage, and a detection A short-circuit / arc discriminating unit that discriminates a short-circuit period and an arc period from the waveform of the welding output voltage, a polarity ratio command unit that commands a predetermined ratio of reverse polarity and positive polarity, A first delay circuit section that delays the output signal by a first predetermined time; a second delay circuit section that delays the output signal of the short-circuit / arc discrimination section by a second predetermined time; and an output of the polarity ratio command section A polarity switching control unit for controlling polarity switching by inputting a signal, an output signal of the short-circuit / arc discrimination unit, an output signal of the first delay circuit unit, and an output signal of the second delay circuit unit; Polarity switching When the control unit switches the polarity according to the output signal of the polarity ratio command unit, the switching of the polarity is prohibited during the short circuit period, and the switching from the reverse polarity to the positive polarity corresponding to the polarity ratio is started from the time of the short circuit open arc regeneration. If it occurs during the short-circuit period delayed for the first predetermined time, the polarity switching is prohibited and the polarity is switched at the end of the delayed short-circuit period, and the polarity is reversed from the positive polarity corresponding to the polarity ratio. When the switching to the occurrence of the switching occurs during the short-circuit period delayed by the second predetermined time from the short-circuit open arc regeneration time, the switching of the polarity is prohibited and the consumption is switched to the polarity at the end of the delayed short-circuit period. Electrode arc welding power supply.

In a consumable electrode arc welding power source that alternately and repeatedly switches the polarity of the welding output voltage applied between the consumable electrode and the base material between a reverse polarity and a positive polarity, a welding voltage detection unit that detects the welding output voltage, and a detection A short-circuit / arc discriminating unit that discriminates a short-circuit period and an arc period from the waveform of the welding output voltage, a first delay circuit unit that delays an output signal of the short-circuit / arc discriminating unit for a first predetermined time, and A second delay circuit for delaying the output signal of the short-circuit / arc discriminating unit by a second predetermined time, an output signal of the polarity ratio command unit, an output signal of the short-circuit / arc discriminating unit, and the first delay circuit unit A polarity ratio command unit that inputs an output signal and an output signal of the second delay circuit unit to command a predetermined ratio of reverse polarity and positive polarity; and an output signal of the polarity ratio command unit that inputs a polarity Control switching A polarity switching control unit, wherein the polarity ratio command unit outputs a polarity switching output signal corresponding to a predetermined ratio to the polarity switching control unit to switch the polarity, and during the short circuit period, the polarity ratio time count In the case of reverse polarity, the polarity ratio time count is also prohibited during the short-circuit period delayed for the first predetermined time from the time of short-circuit open arc regeneration, and the polarity is switched. A consumable electrode type arc welding power source which prohibits the time counting of the polarity ratio and switches the polarity during the short-circuit period delayed for the second predetermined time from the time.

7. The polarity switching control method and consumable electrode type according to claim 1, wherein at least one of the first predetermined time and the second predetermined time is determined by a welding current command value. Arc welding power supply.

6. The polarity switching control according to claim 1, wherein at least one of the first predetermined time and the second predetermined time is determined by the type of the shielding gas and the type of the consumable electrode. Method and consumable electrode arc welding power source.

6. The method according to claim 1, wherein at least one of the first predetermined time and the second predetermined time is determined by a welding current command value, a type of shield gas, and a type of consumable electrode. And a consumable electrode type arc welding power source.