JP2005169429A - Resistance welding method, and resistance welding power supply device - Google Patents

Resistance welding method, and resistance welding power supply device Download PDF

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JP2005169429A
JP2005169429A JP2003409927A JP2003409927A JP2005169429A JP 2005169429 A JP2005169429 A JP 2005169429A JP 2003409927 A JP2003409927 A JP 2003409927A JP 2003409927 A JP2003409927 A JP 2003409927A JP 2005169429 A JP2005169429 A JP 2005169429A
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welding
current
component
resistance
power source
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Hidehiko Sugimoto
英彦 杉本
Sumihiro Fujii
純裕 藤井
Kazuo Washida
一夫 鷲田
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Fukui Prefecture
Fujii Optical Co Ltd
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Fujii Optical Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a resistance welding equipment and a resistance welding method in which melting deformation, thermal deformation, degradation of base metal characteristics, and degradation of strength do not occur, and the quality and reliability of welding are not degraded between dissimilar metal components or even between similar metal components when the heat capacity is small or the heat capacity is considerably different from each other. <P>SOLUTION: In the resistance welding, the welding current including the high frequency components with the skin effect runs while maintaining the pressure applied to a component to be welded so as to keep the contact resistance of considerably high value in order to concentrate the heat to a welding surface, and the welding is performed by locally and instantaneously performing heating, melting and bonding of a surface layer of the welding surface by these two synergistic effects. By the local and instantaneous heating effect, high quality and high reliability can be obtained in the welding of dissimilar metal components, or the welding of similar metal components of small heat capacity or similar metal components considerably different in heat capacity from each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は異種金属部品同士または熱容量が大きく異なる同種金属部品同士または熱容量の小さな同種金属部品同士を抵抗溶接する抵抗溶接電源装置及び抵抗溶接方法に関するものである。   The present invention relates to a resistance welding power supply apparatus and a resistance welding method for resistance welding of dissimilar metal parts, similar metal parts having greatly different heat capacities, or similar metal parts having a small heat capacity.

一般に、抵抗溶接は次のように行われる。固定電極と電動機、空気圧シリンダー等で駆動される加圧軸に取り付けた可動電極の間に、被溶接部品を挟み、初期加圧力を加えながら、適当な時間保持する。次に、加熱のための加圧力を加えながら、固定電極と可動電極間に接続した溶接電源から、被溶接部品に溶接電流を通電する。該溶接電流は、各被溶接部品の固有抵抗と接合面の接触抵抗によるジュール熱を発生し、被溶接部品は溶融し溶着する。その後、溶接電流の通電を終了させ、冷却保持のための加圧力を加えながら、冷却、固化するの待つ。以上、一連の工程により溶接が完了する。   Generally, resistance welding is performed as follows. A part to be welded is sandwiched between a fixed electrode and a movable electrode attached to a pressure shaft driven by an electric motor, a pneumatic cylinder or the like, and is held for an appropriate time while applying an initial pressure. Next, a welding current is applied to the parts to be welded from a welding power source connected between the fixed electrode and the movable electrode while applying a pressing force for heating. The welding current generates Joule heat due to the specific resistance of each welded part and the contact resistance of the joint surface, and the welded part is melted and welded. Thereafter, energization of the welding current is terminated, and the cooling and solidification are waited while applying a pressurizing force for cooling and holding. As described above, welding is completed through a series of steps.

抵抗溶接の品質、信頼性は、前記した一連の溶接工程中に被溶接部品に印加する加圧力パターン、溶接電流通電パターン、およびそれらの相互関係、また、それぞれの実行精度に依存する。そこで、加圧力と溶接電流の制御に関して様々な方法が考案されている。例えば、特許文献１には、溶接電流通電開始時の加圧力を確実に設定加圧力に一致させるために、エアシリンダを電空比例弁により制御する装置が開示されている。また、特許文献２には異物の挟み込みを検出回避しながら加圧制御するため、電極間の導通状態を検出しながら加圧する抵抗溶接機が開示されている。また、特許文献３には、被溶接物相互間に隙間が生じた場合に、その隙間をゼロにした後、所定の加圧力により加圧する抵抗溶接機が開示されている。また、特許文献４には、溶接前に被溶接部品全体の導通抵抗を測定し、導通抵抗が大きいほど加圧力を大きく設定する抵抗溶接機が開示されている。また、特許文献５には、サーボモータの電機子電流を制御して、加圧力を連続的または断続的に増加させる加圧力制御法が開示されている。 The quality and reliability of resistance welding depend on the pressurizing pattern applied to the parts to be welded during the series of welding processes described above, the welding current conduction pattern, and their interrelationships, and the execution accuracy of each. Therefore, various methods have been devised for controlling the pressing force and the welding current. For example, Patent Document 1 discloses a device that controls an air cylinder with an electropneumatic proportional valve in order to ensure that the applied pressure at the start of welding current energization matches the set applied pressure. Patent Document 2 discloses a resistance welding machine that performs pressurization while detecting a conduction state between electrodes in order to perform pressurization control while avoiding detection of foreign object pinching. Patent Document 3 discloses a resistance welder that, when a gap is generated between workpieces, pressurizes with a predetermined pressure after setting the gap to zero. Further, Patent Document 4 discloses a resistance welding machine that measures the conduction resistance of the entire part to be welded before welding, and sets a larger pressure as the conduction resistance increases. Further, Patent Document 5 discloses a pressure control method for controlling the armature current of a servo motor to increase the pressure continuously or intermittently.

抵抗溶接で使用する電源は、一般に、（１）コンデンサーに電荷を蓄えた直流電源、（２）５０Ｈｚや６０Ｈｚの商用交流をサイリスタ素子やトライアック素子等の半導体素子で導通角制御し、それを変圧器で降圧した電源、（３）５０Ｈｚや６０Ｈｚの商用交流を整流回路、平滑回路で直流とし、その直流をパワートランジスタ等の半導体スイチィング素子でスイッチングして交流に変換し、それを変圧器で降圧したインバータ交流式電源 等が用いられる。特許文献６には、溶接通電中の電流過剰変化を抑制することを目的に、被溶接部の板厚や材質などの溶接条件に応じて、溶接電流周波数を変化させるインバータ交流式抵抗溶接方法が開示されている。しかし、これらの何れの電源においても、溶接電流に含まれる最も振幅が大きい交流成分の周波数は、たかだか４００Ｈｚ程度であり、本発明の８００Ｈｚ程度から１０００Ｈｚ程度以上のものは無い。また、通電中に溶接電流に含まれる最も振幅が大きい交流成分の周波数をある目的を持って任意に変更することはない。
特開平９−２７７０６３号公報 特開２００２−２０５１７４号公報 特開２０００−２１８３７９号公報 特開２００２−２８７９０号公報 特開平９−８５４５６号公報 特開２００１−１０５１５５号公報 The power source used for resistance welding is generally (1) a DC power source in which electric charge is stored in a capacitor, and (2) a commercial AC current of 50 Hz or 60 Hz is subjected to conduction angle control with a semiconductor element such as a thyristor element or a triac element and transformed (3) 50Hz or 60Hz commercial alternating current is converted into direct current by a rectifier circuit and smoothing circuit, and the direct current is switched by a semiconductor switching element such as a power transistor and converted to alternating current, and it is stepped down by a transformer. Inverter AC type power supply etc. are used. Patent Document 6 discloses an inverter AC resistance welding method in which the welding current frequency is changed in accordance with welding conditions such as a plate thickness and a material of a welded part for the purpose of suppressing an excessive change in current during welding energization. It is disclosed. However, in any of these power supplies, the frequency of the AC component having the largest amplitude included in the welding current is at most about 400 Hz, and none of the present invention has about 800 Hz to 1000 Hz or more. Further, the frequency of the AC component having the largest amplitude included in the welding current during energization is not arbitrarily changed with a certain purpose.
Japanese Patent Laid-Open No. 9-277063 JP 2002-205174 A JP 2000-218379 A JP 2002-28790 A JP-A-9-85456 JP 2001-105155 A

異種金属部品同士を抵抗溶接する場合、各金属の電気抵抗率が異なるために、各被溶接部品の固有抵抗が異なり、溶接電流により発生するジュール熱量が異なる。また、たとえ発生するジュール熱量が同じでも、各金属の比熱と熱伝導率が異なるために、各被溶接部品が上昇する温度が異なる。また、たとえ各被溶接部品が同じ温度になって、各金属の融点が異なるために、その温度が融点の高い金属の融点程度でないと溶接が出来ない。このように、異種金属部品同士を溶接するには、電気抵抗率、比熱、熱伝導率の違いを乗り越えて、融点の高い金属の融点程度まで両被溶接部品の温度を上げる必要がある。   When resistance welding of dissimilar metal parts, the electrical resistivity of each metal is different, so the specific resistance of each part to be welded is different, and the amount of Joule heat generated by the welding current is different. Moreover, even if the generated Joule heat amount is the same, the specific heat and the thermal conductivity of each metal are different, so that the temperature at which each welded part rises is different. Further, even if the parts to be welded are at the same temperature and the melting points of the metals are different, welding is not possible unless the temperature is about the melting point of the metal having a high melting point. Thus, in order to weld dissimilar metal parts, it is necessary to overcome the differences in electrical resistivity, specific heat, and thermal conductivity and raise the temperatures of both parts to be welded to the melting point of a metal having a high melting point.

しかし、両被溶接部品の温度を融点の高い被溶接部品の融点程度まで上昇させた場合、融点の低い方の被溶接部品は過加熱となり、溶接面及びその近傍で溶融変形や熱変形が発生し、熱影響部が広範囲に拡大し、結晶粒の粗大化等による母材特性の劣化、強度低下が発生し、溶接の品質や信頼性が低下する。 However, if the temperature of both parts to be welded is raised to the melting point of the part to be welded with a high melting point, the part to be welded with the lower melting point will be overheated, and melting and thermal deformation will occur at and near the weld surface. However, the heat-affected zone expands in a wide range, and the base material characteristics are deteriorated and the strength is lowered due to the coarsening of crystal grains, so that the quality and reliability of welding are lowered.

熱容量が大きく異なる同種金属部品同士を抵抗溶接する場合、熱容量が大きい被溶接部品を適正な溶接温度まで加熱すると、熱容量が小さな被溶接部品は過加熱になり、前記した問題が発生する。 When the same kind of metal parts having greatly different heat capacities are resistance-welded, if the parts to be welded having large heat capacities are heated to an appropriate welding temperature, the parts to be welded having small heat capacities are overheated, and the above-described problems occur.

細い線材部品などの熱容量の小さな同種金属部品同士を溶接する場合、熱容量が小さいために、溶接面のみならず、部品全体が加熱され、溶融変形や熱変形が発生し、また、熱影響部が広範囲に拡大し、結晶粒の粗大化等による母材特性の劣化、強度低下が発生し、溶接の品質や信頼性が低下する。 When welding the same kind of metal parts with small heat capacity such as thin wire rod parts, the heat capacity is small, so not only the welding surface but the whole part is heated, melting deformation and heat deformation occur, and the heat affected zone Expanding over a wide area, deterioration of base material properties and strength reduction due to coarsening of crystal grains, etc. occur, and the quality and reliability of welding deteriorate.

本発明が解決しようとする課題はこれらの問題点であり、異種金属部品同士また同種金属部品同士でも熱容量が小さな場合や熱容量が大きく異なる場合、溶融変形、熱変形、母材特性の劣化、強度低下を起こさせず、溶接の品質や信頼性を低下させない抵抗溶接装置および抵抗溶接方法を提供する。 The problems to be solved by the present invention are these problems.When the heat capacity is small or the heat capacities are different even between different metal parts or between the same kind of metal parts, melting deformation, heat deformation, deterioration of base material characteristics, strength Provided are a resistance welding apparatus and a resistance welding method that do not cause deterioration and do not deteriorate the quality and reliability of welding.

本発明は異種金属部品同士また同種金属部品同士でも熱容量が小さな場合や熱容量が大きく異なる場合に、従来のような溶融変形、熱変形、母材特性劣化、強度低下を起こさせず、溶接の信頼性を低下させないで抵抗溶接する方法で、次のような技術的手段を講じてある。互いに対向する２個の電極で、該電極間に設置した被溶接部品を挟み、加圧力を印加しながら、前記両電極間に溶接電源を接続し、被溶接物に溶接電流を流して溶接する抵抗溶接方法において、溶接電流通電中に被溶接部品に印加する加圧力は、溶接電流通電終了後の冷却保持中に被溶接部品に印加する加圧力より小さいこと、かつ、溶接電源から供給される溶接電流は、該溶接電流に含まれる交流成分が直流成分に対して相対的に大きく、最も振幅が大きい交流成分の周波数が８００Ｈｚ程度以上であるものとすることを特徴とすることを主要な条件とする。   The present invention does not cause melting deformation, heat deformation, deterioration of base material characteristics, and strength reduction as in the case where the heat capacity is small or the heat capacity is greatly different even between dissimilar metal parts or between the same metal parts. The following technical measures are taken by resistance welding without reducing the properties. A welding power source is connected between the two electrodes while two parts facing each other are sandwiched between the parts to be welded between the electrodes and a pressing force is applied, and welding is performed by passing a welding current to the workpiece. In the resistance welding method, the applied pressure applied to the welded part during energization of the welding current is smaller than the applied pressure applied to the welded part during cooling and holding after the energization of the welding current, and is supplied from the welding power source. The welding current is characterized in that the AC component included in the welding current is relatively large with respect to the DC component, and the frequency of the AC component having the largest amplitude is about 800 Hz or more. And

前記のような手段を講ずることで、（１）溶接面の接触抵抗を大きく保ちながら溶接電流を通電することになり、被溶接部品の溶接面の表面層にＩ２Ｒのジュール熱が集中する、（２）交流成分が直流成分に対して相対的に大きく、最も振幅が大きい交流成分の周波数が８００Ｈｚ程度から１０００Ｈｚ程度以上である高周波成分を含む溶接電流の表皮効果により、被溶接部品及び溶接面の表面層の電流密度が大きくなり、表面層だけにＩ２Ｒのジュール熱が集中する、と言う二つの物理現象が同時に発生し、その相互作用により、溶接面の表面層だけを瞬間的に加熱、溶融、融着する。その結果、異種金属部品や熱容量の小さな小形の同種金属部品や熱容量の大きく異なる同種金属部品の溶接において、溶接部や部品全体に溶融変形や熱変形が発生したり、また、熱影響部が広範囲に拡大し、結晶粒の粗大化等による母材特性の劣化や強度低下が発生することはなくなり、品質や信頼性の高い溶接が可能となる。 By taking the above-described means, (1) a welding current is applied while maintaining a large contact resistance of the weld surface, and I 2 R Joule heat concentrates on the surface layer of the weld surface of the welded part. (2) Due to the skin effect of the welding current including the high frequency component in which the alternating current component is relatively large with respect to the direct current component and the amplitude of the alternating current component having the largest amplitude is about 800 Hz to about 1000 Hz or more, Two physical phenomena that the current density of the surface layer of the surface increases and the I 2 R Joule heat concentrates only on the surface layer occur at the same time. Heat, melt, and fuse. As a result, in the welding of dissimilar metal parts, small homogeneous metal parts with small heat capacities, and similar metal parts with greatly different heat capacities, melting and thermal deformation may occur in the welded part and the entire part, and there is a wide range of heat affected parts. Thus, the base material characteristics are not deteriorated and the strength is not reduced due to the coarsening of crystal grains, and welding with high quality and reliability is possible.

すなわち、本発明の抵抗溶接は、溶接面に熱を集中させるために、被溶接部品に印加する加圧力を接触抵抗がかなり大きい値を維持できる程度に保ちながら、表皮効果のある高周波成分を含む溶接電流を流すもので、この二つの相乗効果により溶接面の表面層を局部的に、瞬間的に、加熱、溶融、融着させ、溶接を行うものである。この局部的で瞬間的な加熱作用のため、異種金属部品や熱容量の小さな小形の同種金属部品や熱容量の大きく異なる同種金属部品の溶接において、高い品質や高い信頼性が得られることになる。   That is, the resistance welding of the present invention includes a high-frequency component having a skin effect while maintaining the pressure applied to the parts to be welded at such a level that the contact resistance can be maintained at a considerably large value in order to concentrate heat on the welding surface. A welding current is passed, and the surface layer of the welding surface is locally, instantaneously heated, melted, and fused by these two synergistic effects to perform welding. Due to this local and instantaneous heating action, high quality and high reliability can be obtained in welding of dissimilar metal parts, small-sized similar metal parts having a small heat capacity, and similar metal parts having greatly different heat capacities.

本発明は、固定電極とサーボ電動機で駆動される加圧軸に取り付けた可動電極の間に、前記サーボ電動機を駆動して被溶接部品を挟み、加圧力を印加し、前記両電極間に溶接電源を接続し、前記被溶接物に溶接電流を流して溶接する抵抗溶接方法において実施する。また、溶接電源はインバータ交流電源を用いる。以下、本発明にかかる実施例を図面に基づいて詳細に説明する。 The present invention drives a servo motor to sandwich a part to be welded between a fixed electrode and a movable electrode attached to a pressure shaft driven by a servo motor, applies pressure, and welds between the electrodes. This is performed in a resistance welding method in which a power source is connected and welding is performed by passing a welding current through the workpiece. Further, an inverter AC power source is used as the welding power source. Embodiments according to the present invention will be described below in detail with reference to the drawings.

本発明を実施する抵抗溶接装置の全体構成図を図１に示す。サーボ電動機１を直進運動ユニット２に接続し、そのユニット２に加圧軸３を取り付け、その加圧軸３に可動電極４を取り付ける。その可動電極４に対向する位置に固定電極５を設置する。サーボ電動機１は、サーボ電動機駆動回路７を経てサーボ電動機制御回路８に接続される。サーボ電動機１は、指定した速度で回転する速度制御モードと、指定した電機子電流を発生する、つまり指定したトルクを発生するトルク制御モードとを併せ持ち、サーボ電動機制御回路８からの信号により、動作モードの選択と速度の大きさとトルクの大きさが決定される。直進運動ユニット２には、原点位置に原点位置検出センサー９を、および可動電極４が被溶接部品６ｂに接触する位置に、速度制御モードとトルク制御モードを切り替えるモード切替位置検出センサー１０を設ける。両電極４，５間には、本発明の抵抗溶接電源装置１２の出力端子を接続する。抵抗溶接装置の全体制御指示装置１１は、溶接条件を受け付け、一連の溶接工程を制御管理するもので、サーボ電動機制御回路８と抵抗溶接電源装置１２に対して、動作指示信号、制御信号、または、溶接条件情報信号を出す。   An overall configuration diagram of a resistance welding apparatus for carrying out the present invention is shown in FIG. The servo motor 1 is connected to the linear motion unit 2, the pressure shaft 3 is attached to the unit 2, and the movable electrode 4 is attached to the pressure shaft 3. A fixed electrode 5 is installed at a position facing the movable electrode 4. The servo motor 1 is connected to a servo motor control circuit 8 via a servo motor drive circuit 7. The servo motor 1 has both a speed control mode that rotates at a specified speed and a torque control mode that generates a specified armature current, that is, generates a specified torque, and operates according to a signal from the servo motor control circuit 8. The mode selection, speed magnitude and torque magnitude are determined. The linear motion unit 2 is provided with an origin position detection sensor 9 at the origin position and a mode switching position detection sensor 10 for switching between the speed control mode and the torque control mode at a position where the movable electrode 4 contacts the workpiece 6b. An output terminal of the resistance welding power source device 12 of the present invention is connected between the electrodes 4 and 5. The overall control instruction device 11 of the resistance welding device receives welding conditions and controls and manages a series of welding processes. The operation instruction signal, the control signal, or the The welding condition information signal is output.

本発明を実施する一連の溶接工程条件を図２のタイムチャートに示す。抵抗溶接装置の全体制御指示装置１１からの始動信号２６により可動電極下降工程２１が始まり、サーボ電動機１が速度制御モードで動作し、可動電極４は、原点位置から、指定された速度で、モード切替位置検出センサー１０の信号が検出されるまで下降する。次は初期加圧工程２２で、サーボ電動機１は、トルク制御モードに切り替わり、指定されたトルクを発生し、その結果、可動電極４は、指定された加圧力で被溶接部品６ａ，６ｂを加圧する。次は通電加熱工程２３で、この工程も同様に、指定された加圧力で被溶接部品６ａ，６ｂに加圧を加えながら、本発明の抵抗溶接電源装置１２から、両電極４，５を通して被溶接部品６ａ，６ｂに、指定された溶接電圧周波数パターン２８、指定された溶接電圧デューティ比パターン２９の溶接電圧を印加し、溶接電流を流し、被溶接部品６ａ，６ｂを加熱溶融する。次は冷却保持工程２４で、溶接電流通電を終了し、指定された加圧力を加えながら、冷却、固化するのを待つ。次は可動電極上昇復帰工程２５で、サーボ電動機１を速度制御モードに切り替え動作させ、可動電極４を指定された速度で上昇させ、原点位置検出センサー９の信号が検出されると停止させる。被溶接部品６ａ，６ｂの材質や大きさ等により、各工程で印加する加圧力印加パターン２７ａ，２７ｂ、２７ｃを使い分ける。溶接電圧周波数パターン２８は、被溶接部品６ａ，６ｂの大きさ、材質、または形状によって、周波数とそのパターンを設定する。以上、一連の工程により溶接が完了する。 A series of welding process conditions for carrying out the present invention are shown in the time chart of FIG. The movable electrode lowering step 21 is started by the start signal 26 from the overall control instruction device 11 of the resistance welding apparatus, the servo motor 1 operates in the speed control mode, and the movable electrode 4 is operated at the specified speed from the origin position. It goes down until the signal of the switching position detection sensor 10 is detected. Next, in the initial pressurizing step 22, the servo motor 1 switches to the torque control mode and generates a designated torque. As a result, the movable electrode 4 applies the parts to be welded 6a and 6b with the designated pressure. Press. Next is an energization heating process 23. In this process as well, a pressure is applied to the parts to be welded 6a and 6b with a specified pressure, and the resistance welding power source device 12 of the present invention passes through both electrodes 4 and 5 through the electrodes. The welding voltage of the designated welding voltage frequency pattern 28 and the designated welding voltage duty ratio pattern 29 is applied to the welding parts 6a and 6b, a welding current is passed, and the parts to be welded 6a and 6b are heated and melted. Next, in the cooling and holding step 24, the welding current energization is finished, and the cooling and solidification are waited while applying the specified pressurizing force. Next, in the movable electrode rise return step 25, the servo motor 1 is switched to the speed control mode, the movable electrode 4 is raised at a designated speed, and is stopped when the signal of the origin position detection sensor 9 is detected. Depending on the material and size of the parts to be welded 6a and 6b, the pressure application patterns 27a, 27b and 27c applied in each process are properly used. The welding voltage frequency pattern 28 sets the frequency and its pattern according to the size, material, or shape of the parts to be welded 6a, 6b. As described above, welding is completed through a series of steps.

本発明の抵抗溶接方法は、溶接面に熱を集中させ、瞬間的に溶接面表層を加熱溶融させるために、通電加熱工程中２３に、次の二つの方法を同時に行い、その相互作用による相乗効果を引き出すことを特徴とするものである。   In the resistance welding method of the present invention, in order to concentrate heat on the welding surface and instantaneously heat and melt the surface layer of the welding surface, the following two methods are simultaneously performed during the energization heating process 23, and the synergistic effect of the interaction is performed. It is characterized by drawing out an effect.

一つ目の方法は、通電加熱工程中２３に被溶接部品６ａ，６ｂに印加する加圧力の大きさは、冷却保持工程２４に被溶接部品６ａ，６ｂに印加する加圧力より小さくすることである。その加圧力を印加することで、溶接面の接触抵抗が大きく保たれ、溶接面の表面層における局部的加熱が行われることになる。 The first method is that the pressure applied to the parts to be welded 6a and 6b during the current heating process 23 is made smaller than the pressure applied to the parts to be welded 6a and 6b during the cooling holding process 24. is there. By applying the pressurizing force, the contact resistance of the welding surface is kept large, and local heating in the surface layer of the welding surface is performed.

二つ目の方法は、抵抗溶接電源１２から供給される溶接電流は、該溶接電流に含まれる交流成分が直流成分に対して相対的に大きく、最も振幅が大きい交流成分の周波数が８００Ｈｚ程度から１０００Ｈｚ程度以上のものであるとすることである。このような高周波成分を含む溶接電流は、表皮効果により、被溶接部品６ａ，６ｂの表面層に集中して流れる。つまり、溶接面の表面層に電流が集中して流れる。 In the second method, the welding current supplied from the resistance welding power source 12 is such that the AC component included in the welding current is relatively large with respect to the DC component, and the frequency of the AC component having the largest amplitude is about 800 Hz. That is, the frequency is about 1000 Hz or higher. A welding current including such a high-frequency component flows in a concentrated manner on the surface layers of the parts to be welded 6a and 6b due to the skin effect. That is, current concentrates on the surface layer of the weld surface.

以上の二つの方法を同時に行うことで、溶接面の表面層の抵抗値を大きくし、かつ、そこに溶接電流を集中して流すことになり、ジュール熱が溶接面の表面層に局部的に発生し、瞬間的に、溶接面の表面層を加熱し、溶融、融着する。その結果、異種金属部品や熱容量の小さな小形の同種金属部品や熱容量の大きく異なる同種金属部品の溶接において、溶接部や部品全体の溶融変形や熱変形が発生したり、また、熱影響部が広範囲に拡大し、結晶粒の粗大化等による母材特性の劣化や強度低下が発生することはなくなり、高い品質で高い信頼性のある溶接が可能となる。 By simultaneously performing the above two methods, the resistance value of the surface layer of the welding surface is increased, and the welding current is concentrated there, so that Joule heat is locally applied to the surface layer of the welding surface. Generates and instantaneously heats, melts and fuses the surface layer of the welding surface. As a result, in the welding of dissimilar metal parts, small homogeneous metal parts with small heat capacity, and homogeneous metal parts with greatly different heat capacities, the welded part or the entire part may be melted or thermally deformed, and there is a wide range of heat affected parts. Thus, the base material characteristics are not deteriorated and the strength is not lowered due to the coarsening of crystal grains, and high quality and highly reliable welding is possible.

冷却保持工程２４では、接合面の密着度を向上させるため、通電加熱工程２３の加圧力以上の一定の加圧力を印加しながら、冷却、固化するのを待つ。   In the cooling and holding step 24, in order to improve the adhesion degree of the joint surface, the cooling and solidifying process is awaited while applying a constant applied pressure equal to or higher than the applied pressure in the energizing and heating step 23.

本発明の抵抗溶接電源装置１２を説明する前に従来の電源回路を説明するが、図３は従来の電源ブロック配線図を示している。この従来のインバータ電源は変圧器の二次側にダイオードを挿入し、片電圧方式で使用している。そして溶接電流は変圧器の二次側から溶接治具までの配線に含まれるインダクタンス成分により、なまってしまい、図３(ｂ)に示すごとく直流に近い電流となって高周波成分は含まれない。 Prior to describing the resistance welding power supply device 12 of the present invention, a conventional power supply circuit will be described. FIG. 3 shows a conventional power supply block wiring diagram. This conventional inverter power supply uses a single-voltage method by inserting a diode on the secondary side of the transformer. The welding current is distorted by the inductance component included in the wiring from the secondary side of the transformer to the welding jig, and becomes a current close to direct current as shown in FIG.

図４も従来の電源ブロック配線図を示していて、変圧器の二次側にダイオードを挿入してないので両電圧で使用することが出来るが、しかしこの場合でもインバータ回路においてスイッチング毎に電圧極性を変化させないので、変圧器にかかる電圧極性はスイッチング毎には変化しない。その為に溶接電流は図４（ｂ）に示すように、リップルを含む低周波の交流となり、すなわち高周波成分を含まないために本発明は該電源装置を利用することは出来ない。リップル程度では高周波成分としてのパワーが小さい。   FIG. 4 also shows a conventional power supply block wiring diagram. Since no diode is inserted on the secondary side of the transformer, it can be used with both voltages. However, even in this case, the polarity of the voltage is different for each switching in the inverter circuit. Therefore, the voltage polarity applied to the transformer does not change every switching. Therefore, as shown in FIG. 4B, the welding current becomes a low-frequency alternating current including ripples, that is, since the high-frequency component is not included, the present invention cannot use the power supply device. At the ripple level, the power as a high frequency component is small.

そこで、本発明の抵抗溶接電源装置１２は変圧器の二次側に、交流成分が直流成分に対して相対的に大きく、最も振幅が大きい交流成分の周波数が８００Ｈｚ程度から１０００Ｈｚ程度以上である高周波成分を多く含む電流を流せる回路構成にしている。図５は本発明の抵抗溶接電源装置を示すブロック図であるが、特徴は次の４点にある。
(１)電源装置のインバータ回路において，スイッチング毎に電圧極性を変えて，変圧器にかかる電圧極性をスイッチング毎に変化させ，変圧器の二次側に流れる電流に含まれる高周波成分を大きくする。
(２)電源装置の変圧器のインダクタンスを出来るだけ小さくしている。すなわち、抵抗溶接電源用変圧器において、変圧器の巻き線を２本以上の並列巻き線あるいはリッツ線を巻き線として使用することで変圧器のインダクタンスを小さくして大電流が流れ易くしている。
(３)変圧器の二次側から抵抗溶接装置の電極までの配線を二本以上の並列配線またはリッツ線で構成している。
(４)インバータの波形はワンパルス幅変調が基本であるが、ツーパルス以上でもかまわないし、今回の実施例のように、正電圧−負電圧、又は逆に負電圧−正電圧の繰り返しでもよい。 Therefore, the resistance welding power source device 12 of the present invention is arranged on the secondary side of the transformer with a high frequency in which the AC component is relatively large with respect to the DC component and the frequency of the AC component having the largest amplitude is about 800 Hz to about 1000 Hz. The circuit configuration allows a current containing many components to flow. FIG. 5 is a block diagram showing the resistance welding power source device of the present invention, characterized in the following four points.
(1) In the inverter circuit of the power supply device, the voltage polarity is changed for each switching, the voltage polarity applied to the transformer is changed for each switching, and the high-frequency component contained in the current flowing on the secondary side of the transformer is increased.
(2) The inductance of the power supply transformer is made as small as possible. That is, in a resistance welding power source transformer, by using two or more parallel windings or a litz wire as a winding, the inductance of the transformer is reduced and a large current flows easily. .
(3) The wiring from the secondary side of the transformer to the electrode of the resistance welding apparatus is composed of two or more parallel wirings or litz wires.
(4) The waveform of the inverter is basically one-pulse width modulation, but it may be two pulses or more, and may be a positive voltage-negative voltage, or conversely, a negative voltage-positive voltage, as in this embodiment.

従来は、高周波電流による抵抗溶接では、変圧器や配線のインダクタンスにより溶接に必要な大電流は流すことが出来ないと思われてきたが、本発明は上記(１)、(２)、(３) 、(４)の特徴にて構成することで高周波で大電流を流すことが出来る。   Conventionally, in resistance welding using high-frequency current, it has been considered that a large current required for welding cannot be flowed due to the inductance of a transformer or wiring. However, the present invention has the above (1), (2), (3 ) And (4), it is possible to flow a large current at a high frequency.

図５の抵抗溶接電源装置の動作を説明すると、三相交流５１を整流回路５２で整流し、平滑コンデンサー５３で平滑化して直流電源を作る。そして該直流電源をパワートランジスターで構成したインバータ回路５４で交流に変換し、変圧器５５の一次側に通電する。二次側では大電流となって溶接電流として利用出来る。ここで上記インバータ回路５４は、入力部５８で設定されて記憶部５９で記憶されているインバータのスイッチング周波数、デューティ比及び通電時間を、制御回路６０によって駆動回路６１を通して駆動される。   The operation of the resistance welding power source apparatus of FIG. 5 will be described. A three-phase AC 51 is rectified by a rectifier circuit 52 and smoothed by a smoothing capacitor 53 to produce a DC power source. The DC power source is converted to AC by an inverter circuit 54 constituted by a power transistor, and the primary side of the transformer 55 is energized. The secondary side becomes a large current and can be used as a welding current. Here, the inverter circuit 54 is driven by the control circuit 60 through the drive circuit 61 with the switching frequency, duty ratio, and energization time of the inverter set by the input unit 58 and stored in the storage unit 59.

上記入力部５８はスイッチング周波数、デューティ比、通電時間等の溶接条件を設定する部分であり、全体制御指示装置１１からの溶接条件情報信号を受け付ける。記憶部５９は上記入力部５８に入力された溶接条件を記憶しておく部分である。又表示部は記憶された溶接条件を表示する部分である。そして制御回路６０はインバータの駆動回路６１へ信号を出す部分であり、入力して記憶されたスイッチング周波数、デューティ比、及び通電時間等に基づいて、インバータの駆動回路６１へ駆動信号を送る。   The input unit 58 is a part for setting welding conditions such as a switching frequency, a duty ratio, and an energizing time, and receives a welding condition information signal from the overall control instruction device 11. The storage unit 59 is a part that stores the welding conditions input to the input unit 58. The display part is a part for displaying the stored welding conditions. The control circuit 60 is a part that outputs a signal to the drive circuit 61 of the inverter, and sends a drive signal to the drive circuit 61 of the inverter based on the switching frequency, duty ratio, energization time, and the like that are input and stored.

駆動回路６１は上記制御回路６０からの駆動信号を増幅して、インバータ回路５４のパワートランジスターを駆動し、変圧器５５の一次側へ通電される。同図に示す６２は電流検出回路であり、変圧器５５の一次側と二次側の各電流を検出して異常の有無を見極める。図６は変圧器５５へ入る一次側電圧波形６５と二次側電流波形６６を示している。この電源装置はインバータ回路５４で変圧器５５にかかる電圧極性をスイッチング毎に切り換え、二次側の溶接電流をプラスとマイナスにパルス状に大きく振ることが出来る。   The drive circuit 61 amplifies the drive signal from the control circuit 60, drives the power transistor of the inverter circuit 54, and is energized to the primary side of the transformer 55. 62 shown in the figure is a current detection circuit, which detects each current on the primary side and secondary side of the transformer 55 to determine whether there is an abnormality. FIG. 6 shows a primary side voltage waveform 65 and a secondary side current waveform 66 entering the transformer 55. In this power supply apparatus, the voltage polarity applied to the transformer 55 is switched by the inverter circuit 54 at every switching, and the welding current on the secondary side can be greatly pulsated positively and negatively.

本発明の抵抗溶接では周波数を一般に８００Ｈｚ程度から１０００Ｈｚ程度以上とし、従来使用されているシーム溶接機の周波数が４００Ｈｚ程度であるのに比較すれば、極端に高い周波数の電流が流れる。そして本発明では変圧器５５の巻き線、変圧器５５から電極端子５７ａ，５７ｂまでのリード線５６(配線)の長さを短くすると共に、該リード線５６を並列配線または細い線を束にしたリッツ線で構成することで、二次側に発生した高い周波数の大電流を電極端子５７ａ，５７ｂまで導いて抵抗溶接することが出来るようにしている。   In the resistance welding of the present invention, the frequency is generally set to about 800 Hz to about 1000 Hz or more, and an extremely high frequency current flows as compared with a conventionally used seam welder having a frequency of about 400 Hz. In the present invention, the length of the winding of the transformer 55 and the length of the lead wire 56 (wiring) from the transformer 55 to the electrode terminals 57a and 57b are shortened, and the lead wire 56 is bundled in parallel wiring or thin wires. By using a litz wire, a high-frequency large current generated on the secondary side can be guided to the electrode terminals 57a and 57b for resistance welding.

以上述べたように、本発明の抵抗溶接電源装置及び抵抗溶接方法は高周波成分を含んだ大電流を流すことが出来るようにしたものである。   As described above, the resistance welding power source apparatus and the resistance welding method of the present invention are configured to allow a large current containing a high frequency component to flow.

抵抗溶接装置全体構成図。The whole resistance welding apparatus block diagram. 抵抗溶接工程のタイムチャート。Time chart of resistance welding process. 従来の抵抗溶接装置の電源回路及び電圧波形と電流波形。The power supply circuit and voltage waveform and current waveform of a conventional resistance welding apparatus. 従来の抵抗溶接装置の電源回路及び電圧波形と電流波形。The power supply circuit and voltage waveform and current waveform of a conventional resistance welding apparatus. 本発明の抵抗溶接電源装置のブロック図。The block diagram of the resistance welding power supply device of this invention. 変圧器の一次側電圧波形と二次側電流波形。Transformer primary voltage waveform and secondary current waveform.

符号の説明Explanation of symbols

１ サーボ電動機
２ 直進運動ユニット
３ 加圧軸
４ 可動電極
５ 固定電極
６ 被溶接部品
７ サーボ電動機駆動回路
８ サーボ電動機制御回路
９ 原点位置検出センサー
１０ モード切替位置検出センサー
１１ 全体制御指示装置
１２ 抵抗溶接電源装置
２１ 可動電極下降工程
２２ 初期加圧工程
２３ 通電加熱工程
２４ 冷却保持工程
２５ 可動電極上昇復帰工程
２６ 始動信号
２７ 加圧力印加パターン
２８ 溶接電圧周波数パターン
２９ 溶接電圧デューティ比パターン
５１ 三相交流
５２ 整流回路
５３ 平滑コンデンサー
５４ インバータ回路
５５ 変圧器
５６ リード線
５７ 電極端子
５８ 入力部
５９ 記憶部
６０ 制御回路
６１ 駆動回路
６２ 電流検出回路
６５ 一次側電圧波形
６６ 二次側電流波形
DESCRIPTION OF SYMBOLS 1 Servo motor 2 Linear motion unit 3 Pressurization shaft 4 Movable electrode 5 Fixed electrode 6 Parts to be welded 7 Servo motor drive circuit 8 Servo motor control circuit 9 Origin position detection sensor 10 Mode switching position detection sensor 11 Overall control instruction device 12 Resistance welding Power supply device 21 Movable electrode lowering step 22 Initial pressurizing step 23 Current heating step 24 Cooling and holding step 25 Movable electrode rising return step 26 Start signal 27 Pressure application pattern 28 Welding voltage frequency pattern 29 Welding voltage duty ratio pattern 51 Three-phase AC 52 Rectifier circuit 53 Smoothing capacitor 54 Inverter circuit 55 Transformer 56 Lead wire 57 Electrode terminal 58 Input unit 59 Storage unit 60 Control circuit 61 Drive circuit 62 Current detection circuit 65 Primary side voltage waveform 66 Secondary side current waveform

Claims (8)

互いに対向する２個の電極で、該電極間に設置した被溶接部品を挟み、加圧力を印加しながら、前記両電極間に溶接電源を接続し、被溶接物に溶接電流を流して溶接する抵抗溶接方法において、溶接電流通電中に被溶接部品に印加する加圧力は、溶接電流通電終了後の冷却保持中に被溶接部品に印加する加圧力より小さいこと、かつ、溶接電源から供給される溶接電流は、該溶接電流に含まれる交流成分が直流成分に対して相対的に大きく、最も振幅が大きい交流成分の周波数が８００Ｈｚ程度以上であるものとすることを特徴とする抵抗溶接の方法。 A welding power source is connected between the two electrodes while two parts facing each other are sandwiched between the parts to be welded between the electrodes and a pressing force is applied, and welding is performed by passing a welding current to the workpiece. In the resistance welding method, the applied pressure applied to the welded part during energization of the welding current is smaller than the applied pressure applied to the welded part during cooling and holding after the energization of the welding current, and is supplied from the welding power source. The welding current is characterized in that the AC component contained in the welding current is relatively large with respect to the DC component, and the frequency of the AC component having the largest amplitude is about 800 Hz or more. 溶接電源から供給される溶接電流は、該溶接電流に含まれる交流成分が直流成分に対して相対的に大きく、最も振幅が大きい交流成分の周波数が１０００Ｈｚ程度以上であるものとすることとした請求項１記載の抵抗溶接の方法。 The welding current supplied from the welding power source is such that the AC component included in the welding current is relatively large with respect to the DC component, and the frequency of the AC component having the largest amplitude is about 1000 Hz or more. Item 2. The resistance welding method according to Item 1. 溶接電源から供給される溶接電流は、該溶接電流に含まれる交流成分が直流成分に対して相対的に大きく、最も振幅が大きい交流成分の周波数を溶接電流通電中に任意に変化させるものとすることとした請求項１記載の抵抗溶接の方法。 The welding current supplied from the welding power source is such that the AC component included in the welding current is relatively large with respect to the DC component, and the frequency of the AC component having the largest amplitude is arbitrarily changed during the energization of the welding current. The resistance welding method according to claim 1. 対向する２個の電極で、該電極間に設置した被溶接部品を挟み、加圧力を印加しながら、前記両電極間に溶接電源を接続し、被溶接物に溶接電流を流して溶接する抵抗溶接機の抵抗溶接電源装置において、直流電源を交流電源に変換した後、変圧器の一次側に接続し、該変圧器の二次側電流を溶接電流とし、該溶接電流に含まれる交流成分が直流成分に対して相対的に大きく、最も振幅が大きい交流成分の周波数が８００Ｈｚ程度以上であることを特徴とする抵抗溶接電源装置。 A resistance to weld by placing a welding power source between the two electrodes facing each other and sandwiching the part to be welded between the two electrodes while applying pressure, and applying a welding current to the work piece In a resistance welding power source apparatus of a welding machine, after converting a DC power source to an AC power source, it is connected to the primary side of the transformer, the secondary side current of the transformer is set as a welding current, and the AC component included in the welding current is A resistance welding power supply device characterized in that the frequency of an alternating current component that is relatively large with respect to the direct current component and has the largest amplitude is about 800 Hz or more. 最も振幅が大きい交流成分の周波数を１０００Ｈｚ程度以上とした請求項４記載の抵抗溶接電源装置。 The resistance welding power source device according to claim 4, wherein the frequency of the AC component having the largest amplitude is about 1000 Hz or more. 最も振幅が大きい交流成分の周波数を溶接電流通電中に任意に変化可能であるものととした請求項４記載の抵抗溶接電源装置。 5. The resistance welding power source device according to claim 4, wherein the frequency of the AC component having the largest amplitude can be arbitrarily changed during energization of the welding current. 上記変圧器の巻き線を二本以上の並列巻き線又は各巻き線をリッツ線とした請求項４、請求項５、又は請求項６記載の抵抗溶接電源装置。 7. The resistance welding power supply device according to claim 4, wherein the winding of the transformer is two or more parallel windings or each winding is a litz wire. 上記変圧器から抵抗溶接機の電極までの配線を二本以上の並列配線又は該配線をリッツ線とした請求項４、請求項５、請求項６、又は請求項７記載の抵抗溶接電源装置。
The resistance welding power supply device according to claim 4, 5, 6, or 7, wherein the wiring from the transformer to the electrode of the resistance welding machine is two or more parallel wirings or the wiring is a litz wire.
JP2003409927A 2003-12-09 2003-12-09 Resistance welding method, and resistance welding power supply device Pending JP2005169429A (en)

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WO2010038779A1 (en) * 2008-09-30 2010-04-08 高周波熱錬株式会社 Welding device for metal and welding method for metal
JP2010082666A (en) * 2008-09-30 2010-04-15 Neturen Co Ltd Method of welding metallic material
JP2010082665A (en) * 2008-09-30 2010-04-15 Neturen Co Ltd Welding apparatus for metallic material
WO2011013793A1 (en) * 2009-07-31 2011-02-03 高周波熱錬株式会社 Welded structural member and welding method

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010038779A1 (en) * 2008-09-30 2010-04-08 高周波熱錬株式会社 Welding device for metal and welding method for metal
JP2010082666A (en) * 2008-09-30 2010-04-15 Neturen Co Ltd Method of welding metallic material
JP2010082665A (en) * 2008-09-30 2010-04-15 Neturen Co Ltd Welding apparatus for metallic material
US9079266B2 (en) 2008-09-30 2015-07-14 Neturen Co., Ltd. Welding equipment for metallic materials and method for welding metallic materials
US10189112B2 (en) 2008-09-30 2019-01-29 Neturen Co., Ltd. Welding equipment for metallic materials and method for welding metallic materials
WO2011013793A1 (en) * 2009-07-31 2011-02-03 高周波熱錬株式会社 Welded structural member and welding method
JP5467480B2 (en) * 2009-07-31 2014-04-09 高周波熱錬株式会社 Welded structural member and welding method
US9498840B2 (en) 2009-07-31 2016-11-22 Neturen Co., Ltd. Welding structural part and welding method of the same

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