JP2010253561A - Projection welding method of highly conductive material to be welded - Google Patents

Projection welding method of highly conductive material to be welded Download PDF

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JP2010253561A
JP2010253561A JP2010145572A JP2010145572A JP2010253561A JP 2010253561 A JP2010253561 A JP 2010253561A JP 2010145572 A JP2010145572 A JP 2010145572A JP 2010145572 A JP2010145572 A JP 2010145572A JP 2010253561 A JP2010253561 A JP 2010253561A
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JP4940334B2 (en
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Koji Sasaki
佐々木  広治
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Origin Electric Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding method which can simply perform projection welding even between the highly conductive materials to be welded made of copper or aluminum. <P>SOLUTION: Regarding the projection welding method of the highly conductive materials to be welded where the first highly conductive material W1 to be welded and the second highly conductive material W2 to be welded are faced each other in such a manner that projections P1, P2 are confronted, a highly conductive metallic thin sheet W3 made of the same metallic material as that of the first highly conductive material to be welded or the second highly conductive material to be welded is interposed between the projections, and a pulse-shaped welding current is made to flow between the first highly conductive material to be welded and the second highly conductive material to be welded in a state where elastic pressurizing force is applied thereto, the highly conductive metallic thin sheet is made of the one in which a plurality of highly conductive metal foils w are superimposed, and the first highly conductive material to be welded and the second highly conductive material to be welded are provided with recessed parts V1 to V4 receiving the swelling of the highly conductive metal foils generated upon diffusion bonding around the respective projections. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、導電性が非常に高い銅部材又はアルミニウム部材などの高導電性被溶接物部材を簡単に接合するのに適したプロジェクション溶接方法に関する。   The present invention relates to a projection welding method suitable for easily joining highly conductive workpieces such as copper members or aluminum members having very high conductivity.

同種の金属材料同士や、鉄系材料とステンレス材料、あるいは鉄系材料と銅部材、又は鉄系材料とアルミニウム部材料など、融点や導電率など特性の異なる異種金属材料を接合する方法が種々提案されているが、異種金属材料の接合は硬ロウによる接合、あるいは超音波接合、又はかしめ、ボルト締めなど機械的な結合などによって、接合される場合が多かった。また、同種の金属材料同士の抵抗溶接でも、導電率が非常に良好な銅部材と銅部材同士の接合、又はアルミニウム部材とアルミニウム部材同士、あるいは銅部材とアルミニウム部材との接合なども同様の手段で行われていることが多いが、このような接合方法では、導電率が非常に良好な銅部材、アルミニウム部材を用いるという用途から見て、それらの接合部の抵抗を無視できるほどには小さくできない。このような理由もあって、導電率が非常に良好な銅部材同士、アルミニウム部材同士、又は銅部材とアルミニウム部材との抵抗溶接は特に難しいとされている中、界面抵抗を小さくできる抵抗溶接を行う努力が既に行われており、下記のような処理工程を予め行うことによって銅部材とアルミニウム部材との抵抗溶接を可能にする改良技術も開示されている(例えば、特許文献1参照)。   Various proposals for joining different kinds of metal materials with different characteristics such as melting point and conductivity, such as metal materials of the same type, iron-based materials and stainless steel materials, iron-based materials and copper members, or iron-based materials and aluminum part materials However, dissimilar metal materials are often joined by hard soldering, ultrasonic joining, or mechanical joining such as caulking and bolting. The same means can be used for resistance welding of the same kind of metal materials, such as bonding between copper members and copper members with very good conductivity, or bonding between aluminum members and aluminum members, or bonding between copper members and aluminum members, etc. However, in such a joining method, from the viewpoint of using a copper member and an aluminum member having very good conductivity, the resistance of those joints is so small that it can be ignored. Can not. For these reasons, resistance welding that can reduce the interfacial resistance is considered difficult because resistance welding between copper members with very good conductivity, between aluminum members, or between copper members and aluminum members is considered particularly difficult. Efforts have already been made, and an improved technique that enables resistance welding between a copper member and an aluminum member by performing the following processing steps in advance has also been disclosed (for example, see Patent Document 1).

この方法は、銅部材とアルミニウム部材とを直接抵抗溶接することはできないので、抵抗溶接前に予め銅部材の接合表面にスズ膜を形成し、更に処理を行ってその銅部材とスズとの界面に銅とスズとの固溶を生成させたスズ被覆層を形成した後に、そのスズ被覆層とアルミニウム部材とを接触させ、その固溶生成させたスズ被覆層を銅部材とアルミニウム部材との間に介在させた状態で加圧し、溶接電流を流して抵抗溶接を行うものである。この溶接方法を実現するのは、コンデンサ式溶接機ではなくインバータ式溶接機を用いて、高周波の溶接電流を銅部材とアルミニウム部材とに流し、銅部材とアルミニウム部材との接合部を溶融させ、溶融した銅とアルミニウムとを互いに混じり合わせたナゲットを形成して溶接を行うものである。また、異種金属の抵抗溶接に当たっては、予め異種金属の接合部を最適な特殊形状に加工することによって良好な溶接結果が得られる抵抗溶接方法、及び抵抗溶接装置が既に報告されている(例えば、特許文献2〜5参照)。また、拡散接合時にアルミニウム又はマグネシウムなどの接合面の酸化膜や汚れを除去する酸洗いなどの前処理を不要にするために、被溶接物双方にプロジェクションを形成し、それらプロジェクションの頂部同士を当接させて溶接する方法も開示されている(例えば、特許文献6参照)。
特開2001−087866公報 特開平08−118040号公報 特開平10−128550号公報 特開平10−156548号公報 特開平11−033737号公報 特開2002−103056公報
Since this method cannot directly resistance weld a copper member and an aluminum member, a tin film is previously formed on the bonding surface of the copper member before resistance welding, and further processing is performed to obtain an interface between the copper member and tin. After forming a tin coating layer in which a solid solution of copper and tin is formed, the tin coating layer and the aluminum member are brought into contact with each other, and the tin coating layer thus formed is formed between the copper member and the aluminum member. Pressure is applied in a state of being interposed between the electrodes and resistance welding is performed by passing a welding current. This welding method is realized by using an inverter type welding machine instead of a capacitor type welding machine, flowing a high-frequency welding current through the copper member and the aluminum member, and melting the joint between the copper member and the aluminum member, Welding is performed by forming a nugget in which molten copper and aluminum are mixed together. In addition, for resistance welding of dissimilar metals, a resistance welding method and a resistance welding apparatus have been already reported in which good welding results can be obtained by processing joints of dissimilar metals into optimal special shapes in advance (for example, (See Patent Documents 2 to 5). Also, in order to eliminate the need for pre-treatment such as pickling to remove oxide film or dirt on the joint surface such as aluminum or magnesium during diffusion bonding, projections are formed on both objects to be welded, and the tops of the projections are applied to each other. A method of welding in contact with each other is also disclosed (for example, see Patent Document 6).
JP 2001-087866 A Japanese Patent Laid-Open No. 08-1118040 Japanese Patent Laid-Open No. 10-128550 Japanese Patent Laid-Open No. 10-156548 Japanese Patent Laid-Open No. 11-033737 JP 2002-103056 A

しかし、前掲特許文献1で開示された抵抗溶接方法にあっては、銅部材の接合表面にスズを形成し、銅部材とアルミニウム部材との接合部にナゲットを形成する溶接方法であるので、溶接前に銅又はアルミニウムよりも抵抗の大きな低融点金属膜であるスズ膜を形成しなければならない。このことはスズ膜をメッキなどで形成する工程が必要であること、及び銅部材とアルミニウム部材との接合部にスズが混入するために、接合部での抵抗が大きくなるという欠点がある。また、相互の金属が溶融することによって形成されるナゲットの熱によって接合部の周囲のスズがチリとなって飛散するという問題点がある。また、溶接電流の通電時間が長いので、溶接部での発熱が大きく、溶接部だけでなくその周囲が変色したり、変形が大きくなるなどの問題もある。   However, in the resistance welding method disclosed in the above-mentioned Patent Document 1, since it is a welding method in which tin is formed on the joint surface of the copper member and nugget is formed at the joint portion between the copper member and the aluminum member, welding is performed. A tin film, which is a low melting point metal film having a higher resistance than copper or aluminum, must be formed in advance. This has the disadvantages that a step of forming a tin film by plating or the like is necessary, and that tin is mixed into the joint portion between the copper member and the aluminum member, resulting in an increase in resistance at the joint portion. Further, there is a problem in that tin around the joint becomes dust and is scattered by the heat of the nugget formed by melting the mutual metals. Further, since the energization time of the welding current is long, there is a problem that heat generation at the welded portion is large, and not only the welded portion but also its surroundings are discolored and deformation is increased.

前掲の特許文献2〜5に記載されている接合部の構造は特定の構造の異種金属材料からなる被溶接物に適しているが、特に銅部材と銅部材、又はアルミニウム部材とアルミニウム部材、あるいは銅部材とアルミニウム部材との抵抗溶接にはそのまま適用することは難しく、前掲特許文献に開示されている抵抗溶接装置をもってしても安定な接合強度が得られない。また、前掲の特許文献6に記載されているように、銅部材とアルミニウム部材との双方にプロジェクションを設けて互いに突合せて溶接しても、アルミニウム部材に比べて銅部材の塑性流動化が遅いために安定な接合結果は得られず、また、プロジェクション同士を合致させるのは技術的に面倒な問題があり、特許文献6に記載されている抵抗溶接方法を実際の製造ラインに採用することは、今のところコスト的な面などで難しい場合が多い。   The structures of the joints described in the above-mentioned Patent Documents 2 to 5 are suitable for an object to be welded made of a dissimilar metal material having a specific structure, but in particular, a copper member and a copper member, or an aluminum member and an aluminum member, or It is difficult to apply as it is to resistance welding between a copper member and an aluminum member, and a stable joint strength cannot be obtained even with the resistance welding apparatus disclosed in the above-mentioned patent document. Further, as described in the above-mentioned Patent Document 6, even if projections are provided on both the copper member and the aluminum member and they are butt-welded to each other, the plastic fluidization of the copper member is slower than the aluminum member. However, it is technically troublesome to match the projections to each other, and adopting the resistance welding method described in Patent Document 6 in an actual production line At present, it is often difficult in terms of cost.

本発明は前述の問題点を解決し、拡散接合面にスズ膜のような低融点金属膜を形成することなく、銅部材又はアルミニウム部材のように導電率が非常に高い高導電性被溶接物同士を接合部の抵抗を増やすことなく従来の抵抗溶接装置でもって容易に接合でき、安価に接合強度及び外観など溶接品質の高い接合結果が得られる実際的な拡散接合を提供することを主目的としている。   The present invention solves the above-mentioned problems, and does not form a low-melting-point metal film such as a tin film on the diffusion bonding surface, and has a high conductivity such as a copper member or an aluminum member. The main purpose is to provide a practical diffusion bonding that can be easily joined with conventional resistance welding equipment without increasing the resistance of the joints, and that provides a joint result with high welding quality such as joint strength and appearance at a low cost. It is said.

第1の発明は、第1の高導電性被溶接物と第2の高導電性被溶接物との間に溶接電流を流して抵抗溶接を行う高導電性被溶接物のプロジェクション溶接方法であって、前記第1の高導電性被溶接物及び前記第2の高導電性被溶接物はそれぞれプロジェクションを有し、
前記第1の高導電性被溶接物と前記第2の高導電性被溶接物とを前記プロジェクションが対向するように向かい合わせ、前記プロジェクション同士の間に、前記第1の高導電性被溶接物又は前記第2の高導電性被溶接物の金属材料と同一の金属材料からなる高導電性金属薄板を介在させ、前記第1の高導電性被溶接物と前記第2の高導電性被溶接物との間に、弾性的加圧力を加えた状態でパルス状溶接電流を通電することを特徴とする高導電性被溶接物のプロジェクション溶接方法において、高導電性金属薄板は高導電性金属箔を複数枚重ねたものからなり、前記第1の高導電性被溶接物及び前記第2の高導電性被溶接物は、それぞれの前記プロジェクションの周囲に、拡散接合時に生じる前記高導電性金属箔の盛り上がりを受け入れる凹所を備えることを特徴とする高導電性被溶接物のプロジェクション溶接方法を提供する。
The first invention is a projection welding method for a highly conductive workpiece that performs resistance welding by passing a welding current between the first highly conductive workpiece and the second highly conductive workpiece. The first highly conductive workpiece and the second highly conductive workpiece each have a projection,
The first highly conductive work piece and the second high conductive work piece are faced so that the projections face each other, and the first high conductive work piece is interposed between the projections. Alternatively, a highly conductive metal thin plate made of the same metal material as the metal material of the second highly conductive workpiece is interposed, and the first highly conductive workpiece and the second highly conductive workpiece are welded. In a projection welding method for a highly conductive object to be welded, a pulsed welding current is applied in a state where an elastic pressure is applied between the highly conductive metal thin plate and the highly conductive metal foil. And the first highly conductive workpiece and the second highly conductive workpiece are formed around the projections at the time of diffusion bonding. Recess to accept the excitement of Provides a projection welding method of highly conductive object to be welded, characterized in that it comprises.

第2の発明は、前記第1の発明において、高導電性金属薄板は、前記第1の高導電性被溶接物と前記第2の高導電性被溶接物との間から外部に延びて、第3の高導電性被溶接物として作用することを特徴とする高導電性被溶接物のプロジェクション溶接方法。   According to a second invention, in the first invention, the highly conductive thin metal plate extends from between the first highly conductive workpiece and the second highly conductive workpiece, A projection welding method for a high-conductivity workpiece, characterized by acting as a third high-conductivity workpiece.

第1の発明によれば、高導電性金属板が複数の、特に多数の高導電性金属箔を重ねたものからなる場合には、拡散接合時に接合部が組成流動化するために高導電性金属箔の接合部周辺が変形して盛り上がり、この盛り上がりが接合強度に悪影響を与えるので、これら高導電性金属箔の盛り上がりを収容する凹所をプロジェクションの近傍に備えているので、多数の高導電性金属箔を良好に拡散接合することができる。   According to the first invention, when the highly conductive metal plate is composed of a plurality of, in particular, a large number of highly conductive metal foils, the joint is fluidized at the time of diffusion bonding. Around the joint of the metal foil is deformed and swells, and this swell has an adverse effect on the joint strength. Therefore, a recess that accommodates the swell of these highly conductive metal foils is provided near the projection. The conductive metal foil can be diffusion-bonded satisfactorily.

第2の発明によれば、前記第1の発明で得られる効果の他に、第1の高導電性被溶接物と第2の高導電性被溶接物との間から外部に延びる前記高導電性金属薄板を、第3の高導電性被溶接物とすることができるので、使用目的に応じて第3の高導電性被溶接物の形状や大きさを決めれば、用途を広げることができる。   According to the second invention, in addition to the effects obtained in the first invention, the high conductivity extending to the outside from between the first highly conductive workpiece and the second highly conductive workpiece. Since the conductive thin metal plate can be used as a third highly conductive workpiece, if the shape and size of the third highly conductive workpiece can be determined according to the purpose of use, the application can be expanded. .

[実施形態1]
図1によって本発明に係るプロジェクション溶接方法の実施形態1について説明する。先ず、本発明が適用できる範囲は極めて難しいとされている銅又は銅合金同士のプロジェクション溶接(本発明では、プロジェクション溶接又は抵抗溶接は拡散接合と同意義である。)を例として以下に説明する。本明細書においては、「銅部材」とは「銅又は銅合金」を意味し、「アルミニウム部材」とは「アルミニウム又はアルミニウム合金」を意味する。銅部材又はアルミニウム部材は、一般に鋼板やステンレス材料に比べて導電率が高いので、銅部材同士又はアルミニウム部材同士、あるいは銅部材とアルミニウム部材とのプロジェクション溶接は特に難しいとされており、実施形態1を説明する前にこの点について説明する。以下では銅部材について述べる。
[Embodiment 1]
Embodiment 1 of the projection welding method according to the present invention will be described with reference to FIG. First, a description will be given below by taking, as an example, projection welding between copper or copper alloys, to which the present invention can be applied, which is extremely difficult (in the present invention, projection welding or resistance welding has the same meaning as diffusion bonding). . In the present specification, “copper member” means “copper or copper alloy”, and “aluminum member” means “aluminum or aluminum alloy”. Since the copper member or the aluminum member generally has a higher electrical conductivity than the steel plate or the stainless steel material, projection welding between the copper members or between the aluminum members, or between the copper member and the aluminum member is considered to be particularly difficult. Embodiment 1 This point will be described before description. Below, a copper member is described.

金属材料の抵抗溶接は、溶接電流が流れるときに金属材料の有する抵抗及び双方の金属材料の当接面での接触抵抗が生じる発熱によって双方の金属材料の当接面で塑性流動、つまり軟化が起こり、接合が行われる。しかしながら、銅部材の抵抗及び銅部材同士の接触抵抗は極めて小さいためにその抵抗により発熱する発熱量が不足し、要求される接合強度が極めて小さい場合を除いて、満足の行く抵抗溶接結果を得るのは難しいというのが大きな理由である。要求される接合強度が極めて小さい拡散接合は可能であっても、現実に要求される接合強度を満足するには、高導電性被溶接物である銅部材の接合部の形状や表面状態(接触抵抗)、溶接電流の条件、溶接装置の諸々の特性など種々の制約が厳しい上に、予めスズ膜のような低融点金属膜を形成しておかなければならないために実際の製造ラインに適用することは難しかった。   In resistance welding of metal materials, when the welding current flows, the resistance of the metal materials and the heat generated by the contact resistance at the contact surfaces of both metal materials cause plastic flow, that is, softening at the contact surfaces of both metal materials. Occurs and bonding takes place. However, since the resistance of the copper member and the contact resistance between the copper members are extremely small, the amount of heat generated due to the resistance is insufficient, and a satisfactory resistance welding result is obtained unless the required bonding strength is extremely small. The main reason is that it is difficult. Diffusion bonding with extremely low required bonding strength is possible, but in order to satisfy the actual required bonding strength, the shape and surface condition (contact of the copper member, which is a highly conductive workpiece) Resistance), welding current conditions, various characteristics of the welding equipment, and other restrictions are severe, and a low melting point metal film such as a tin film must be formed in advance, so it is applied to an actual production line. That was difficult.

例えば、銅部材が純銅であるとすれば、広く使用されている銅合金からなる溶接電極の抵抗率は銅部材よりも高くなるので、銅部材における発熱よりも溶接電極での発熱の方が当然に大きくなり、銅部材間の接触抵抗と溶接電極と銅部材との接触抵抗とがほぼ同じであるとすれば、銅部材間の接合よりも溶接電極と銅部材との間で接合が起こり易いという不都合が生じる。実際の連続する溶接工程では、溶接電極の表面は僅かながらに汚れが進むので、この傾向はますます起こりやすい状況になる。このことは、銅部材が数mm以下の厚みの薄板、特に2mm程度以下の薄板の場合、銅部材の厚み方向の抵抗が極めて小さくなるために顕著であり、銅部材のプロジェクション、溶接電流波形、抵抗溶接装置などの諸条件を選定しても、銅部材同士の接合面にスズ膜のような比較的抵抗の大きな低融点金属膜が介在しなければ、安定性も含めて満足の行く溶接結果は得られなかった。実施形態1では、従来のように銅部材同士の接合面にスズ膜のような抵抗値の大きな低融点金属膜を形成せずに、第1の被溶接物W1と第2の被溶接物W2との間に高導電性金属薄板W3を介在させ、その間の接触抵抗を増大させることに特徴がある。この接触抵抗は、接合後には当然にゼロとなるので、接合部の抵抗を増やすことはない。   For example, if the copper member is pure copper, the resistance of a widely used copper alloy welding electrode is higher than that of the copper member, so that the heat generation at the welding electrode is naturally better than the heat generation at the copper member. If the contact resistance between the copper members and the contact resistance between the welding electrode and the copper member are substantially the same, the joining between the welding electrode and the copper member is more likely to occur than the joining between the copper members. The inconvenience arises. In an actual continuous welding process, this tendency becomes more and more likely because the surface of the welding electrode is slightly soiled. This is remarkable when the copper member is a thin plate having a thickness of several mm or less, particularly a thin plate having a thickness of about 2 mm or less because the resistance in the thickness direction of the copper member is extremely small. Even if various conditions such as resistance welding equipment are selected, if a low-melting point metal film with a relatively large resistance, such as a tin film, is not present on the joint surface between copper members, satisfactory welding results including stability will be achieved. Was not obtained. In the first embodiment, the first welded object W1 and the second welded object W2 are formed without forming a low-melting point metal film having a large resistance value such as a tin film on the joint surface between the copper members as in the prior art. Is characterized by interposing a highly conductive thin metal plate W3 between the two and increasing the contact resistance therebetween. Since this contact resistance is naturally zero after joining, it does not increase the resistance of the joint.

図1において、銅部材である第1の被溶接物W1の片面にはプロジェクションP1が形成されている。プロジェクションP1は通常のプロジェクションでよいが、その高さは後述の中間部材となる高導電性金属薄板の厚みによって異なる。通常、プロジェクションの高さの上限はプロジェクションの造り易さから決まり、1mm強程度である。銅部材である第2の被溶接物W2の片面にも、プロジェクションP1と同様なプロジェクションP2が形成されている。プロジェクションP1、P2は一般的な構造のリングプロジェクションでも勿論よい。プロジェクションの面積は要求される接合強度などの条件によって決まり、要求される接合強度が得られる大きさであるので様々である。   In FIG. 1, a projection P1 is formed on one surface of a first workpiece W1 that is a copper member. The projection P1 may be a normal projection, but its height varies depending on the thickness of a highly conductive thin metal plate that serves as an intermediate member described later. Usually, the upper limit of the height of the projection is determined by the ease of making the projection and is about 1 mm. A projection P2 similar to the projection P1 is also formed on one surface of the second workpiece W2 that is a copper member. Of course, the projections P1 and P2 may be ring projections having a general structure. The area of the projection depends on conditions such as the required bonding strength, and varies depending on the size with which the required bonding strength can be obtained.

第1の被溶接物W1のプロジェクションP1と第2の被溶接物W2のプロジェクションP2との間には、銅部材からなる高導電性金属薄板W3が介在している。実施形態1の高導電性金属薄板W3の幅、長さは特に制限されず、溶接工程で取り扱い易いものであればよい。この実施形態1のプロジェクション溶接方法では、銅部材からなる第1の被溶接物W1のプロジェクションP1と第2の被溶接物W2のプロジェクションP2との間に銅部材からなる高導電性金属薄板W3を挟み、所定の加圧力を加えた状態で、その加圧力の応答性が高速のプロジェクション溶接装置、例えば後で説明する図8に示すような抵抗溶接装置によって、短時間に大電流を通電し、高導電性金属薄板W3を介して第1の被溶接物W1と第2の被溶接物W2とを接合する。   Between the projection P1 of the first workpiece W1 and the projection P2 of the second workpiece W2, a highly conductive thin metal plate W3 made of a copper member is interposed. The width and length of the highly conductive metal thin plate W3 of Embodiment 1 are not particularly limited as long as they are easy to handle in the welding process. In the projection welding method of the first embodiment, a highly conductive thin metal plate W3 made of a copper member is provided between the projection P1 of the first work piece W1 made of a copper member and the projection P2 of the second work piece W2. In a state where a predetermined pressing force is sandwiched and applied, a large current is passed in a short time by a projection welding device having a high responsiveness of the pressing force, for example, a resistance welding device as shown in FIG. The first workpiece W1 and the second workpiece W2 are joined via the highly conductive metal thin plate W3.

溶接電極1と2との間に挟まれている初期の状態では、第1の被溶接物W1のプロジェクションP1の先端が高導電性金属薄板W3の一方の面に当接し、第2の被溶接物W2のプロジェクションP2の先端が高導電性金属薄板W3の他方の面に当接している。この状態で、図示していない加圧機構が溶接電極1と2との間に加圧力をかけ、加圧力が上昇している過程で溶接トランスの2次巻線N2から、例えばピーク値が数万Aから数十万Aのパルス状の大電流が第1の被溶接物W1と高導電性金属薄板W3と第2の被溶接物W2とを通して通電される。抵抗溶接にあっては、拡散接合に寄与する溶接電流のほとんどは立ち上がりからピーク値近傍までの電流であるので、実施形態1の抵抗溶接では溶接電流がピーク値近傍まで立ち上がる時間が10ms程度以下であり、7ms以下であることが好ましい。このようなパルス幅の狭い急峻なパルス状の大電流が銅部材からなる第1、第2の被溶接物W1、W2及び高導電性金属薄板W3を通して流れるが、通電初期には、プロジェクションP1とP2とに電流が集中する。   In the initial state sandwiched between the welding electrodes 1 and 2, the tip of the projection P1 of the first work piece W1 comes into contact with one surface of the highly conductive metal thin plate W3, and the second work piece is welded. The tip of the projection P2 of the object W2 is in contact with the other surface of the highly conductive thin metal plate W3. In this state, a pressurizing mechanism (not shown) applies pressure between the welding electrodes 1 and 2 and, for example, a peak value is several times from the secondary winding N2 of the welding transformer while the pressure is increasing. A pulsed large current of 10,000 A to several hundred thousand A is energized through the first workpiece W1, the highly conductive thin metal plate W3, and the second workpiece W2. In resistance welding, since most of the welding current that contributes to diffusion bonding is current from the rise to the vicinity of the peak value, in the resistance welding of Embodiment 1, the time for the welding current to rise to the vicinity of the peak value is about 10 ms or less. Yes, preferably 7 ms or less. Such a steep and pulsed large current with a narrow pulse width flows through the first and second workpieces W1 and W2 and the highly conductive thin metal plate W3 made of a copper member. Current concentrates on P2.

この点について詳しく説明すると、溶接電極1を流れるパルス状溶接電流は、先ず溶接電極1と第1の被溶接物W1との当接面から第1の被溶接物W1を通してそのプロジェクションP1に集中し、プロジェクションP1に当接している高導電性金属薄板W3の一方の微小な当接面域の第1の接触抵抗を通して高導電性金属薄板W3内に流れる。更に、パルス状溶接電流は第2の被溶接物W2のプロジェクションP2に当接している高導電性金属薄板W3の他方の微小な当接面域の第2の接触抵抗に集中して流れる。ここで、溶接電極1と第1の被溶接物W1との当接面及び第2の被溶接物W2と溶接電極2との当接面の面積は、第1の被溶接物W1のプロジェクションP1と高導電性金属薄板W3との当接面域及び第2の被溶接物W2のプロジェクションP2と高導電性金属薄板W3との当接面域の面積に比べてはるかに小さい。したがって、第1の被溶接物W1のプロジェクションP1と高導電性金属薄板W3との微小な当接面域の第1の接触抵抗及び第2の被溶接物W2のプロジェクションP2と高導電性金属薄板W3との微小な当接面域の第2の接触抵抗を流れる電流密度は、非常に大きな値になる。   To explain this point in detail, the pulsed welding current flowing through the welding electrode 1 first concentrates on the projection P1 from the contact surface between the welding electrode 1 and the first workpiece W1 through the first workpiece W1. Then, it flows into the highly conductive metal sheet W3 through the first contact resistance of one minute contact surface area of the highly conductive metal sheet W3 that is in contact with the projection P1. Further, the pulsed welding current flows concentratedly on the second contact resistance of the other minute contact surface area of the highly conductive thin metal sheet W3 that is in contact with the projection P2 of the second workpiece W2. Here, the area of the contact surface between the welding electrode 1 and the first workpiece W1 and the contact surface between the second workpiece W2 and the welding electrode 2 is the projection P1 of the first workpiece W1. And the area of the contact surface area between the high conductive metal thin plate W3 and the area of the contact surface area between the projection P2 of the second workpiece W2 and the high conductive metal thin plate W3. Therefore, the first contact resistance of the minute contact surface area between the projection P1 of the first workpiece W1 and the highly conductive metal thin plate W3 and the projection P2 of the second workpiece W2 and the high conductive metal thin plate. The density of current flowing through the second contact resistance in the minute contact surface area with W3 is a very large value.

このことからプロジェクションP1と高導電性金属薄板W3との微小な当接面域及びプロジェクションP2と高導電性金属薄板W3との微小な当接面域での発熱は、溶接電極1と第1の被溶接物W1との当接面及び第2の被溶接物W2と溶接電極2との当接面での発熱に比べてはるかに大きくなり、このように高導電性金属薄板W3が第1、第2の被溶接物W1、W2の間に存在すると、存在しない場合に比べて接触抵抗がほぼ2倍になるから、発熱量はその分だけ大きくなる。したがって、溶接電極1、2の発熱が第1の被溶接物W1及び第2の被溶接物W2よりも大きくても、第1の被溶接物W1のプロジェクションP1と高導電性金属薄板W3との当接部分及び第2の被溶接物W2のプロジェクションP2と高導電性金属薄板W3との当接部分が塑性流動化し、プロジェクションP1とプロジェクションP2と高導電性金属薄板W3との接合面域で拡散接合が行われる。拡散接合後は当然に前記接触抵抗はゼロになるので、その接触抵抗が接合部の抵抗値を増やすことはない。   Therefore, heat generation in the minute contact surface area between the projection P1 and the highly conductive metal thin plate W3 and in the minute contact surface area between the projection P2 and the high conductive metal thin plate W3 is caused by the welding electrode 1 and the first conductive metal sheet W3. The heat generation at the contact surface with the work piece W1 and the contact surface between the second work piece W2 and the welding electrode 2 is much larger, and thus the highly conductive thin metal sheet W3 has the first, If it exists between the 2nd to-be-welded objects W1 and W2, compared with the case where it does not exist, since contact resistance will be almost doubled, the emitted-heat amount will become large by that much. Therefore, even if the heat generation of the welding electrodes 1 and 2 is larger than that of the first workpiece W1 and the second workpiece W2, the projection P1 of the first workpiece W1 and the highly conductive thin metal sheet W3 The contact portion and the contact portion between the projection P2 of the second workpiece W2 and the highly conductive thin metal plate W3 are plastically fluidized and diffused in the joint surface area between the projection P1, the projection P2, and the highly conductive thin metal plate W3. Joining is performed. Since the contact resistance is naturally zero after diffusion bonding, the contact resistance does not increase the resistance value of the junction.

ここで言う接合面域とは、プロジェクションP1と高導電性金属薄板W3との当接部分及びプロジェクションP2と高導電性金属薄板W3との当接部分がそれぞれ塑性流動化する過程で、溶接電極1と2との間にかけられている加圧力によって、当接部分でそれぞれの被溶接物のプロジェクションP1、P2及びその近傍の銅材料が高導電性金属薄板W3の銅材料と互いになじみあって接合が行われたときの面域をいう。したがって、実施形態1の溶接方法では、接合面域はプロジェクションP1、P2の根元面域とプロジェクションP1、P2が僅かに拡がった面域であり、パルス状溶接電流の通電前におけるプロジェクションP1と高導電性金属薄板W3との初期の当接面域及びプロジェクションP2と高導電性金属薄板W3との初期の当接面域よりも大きい。   The joint surface area referred to here is a process in which the contact portion between the projection P1 and the highly conductive metal thin plate W3 and the contact portion between the projection P2 and the high conductive metal thin plate W3 are plastic fluidized, respectively. 2 and 2, the projections P 1 and P 2 of the respective workpieces and the copper material in the vicinity thereof are in contact with the copper material of the highly conductive thin metal sheet W 3 at the contact portion, and are joined. The area when performed. Therefore, in the welding method of the first embodiment, the joint surface area is the base area of the projections P1 and P2 and the area where the projections P1 and P2 are slightly expanded, and the projection P1 and the high conductivity before the pulsed welding current is supplied. Larger than the initial contact surface area between the conductive thin metal plate W3 and the initial contact surface area between the projection P2 and the highly conductive thin metal plate W3.

このプロジェクション溶接方法では、第1の被溶接物W1と第2の被溶接物W2との厚みは関係なく、前述した2mm以下の厚みであっても良好な拡散接合を行うことができる。しかしながら、高導電性金属薄板W3が第1の被溶接物W1及び第2の被溶接物W2に比べて、厚過ぎる場合には下記のような問題が生じる。例えば、高導電性金属薄板W3が第1の被溶接物W1又は第2の被溶接物W2の厚みよりも大きい厚みを有する場合には、パルス状溶接電流の通電に伴うプロジェクションP1と高導電性金属薄板W3との当接部分の第1の接触抵抗による発熱及びプロジェクションP2と高導電性金属薄板W3との当接部分の第2の接触抵抗による発熱は、パルス状溶接電流の通電時間に比べて熱伝導速度が遅いために、パルス状溶接電流の通電中では前記双方の発熱が高導電性金属薄板W3の厚み内方向に熱伝導、つまり内方向に未だ逃げている状態であるので、プロジェクションP1と高導電性金属薄板W3との当接部分での温度上昇が不十分になり、したがって、その当接部分の塑性流動化が不完全な状態になる。同様に、プロジェクションP2と高導電性金属薄板W3との当接部分での塑性流動化も不完全な状態になるので、溶接強度が低下する。この問題を解決するには、パルス状溶接電流のピーク値を更に大きくしなければならない。   In this projection welding method, the thickness of the first workpiece W1 and the second workpiece W2 is not related, and good diffusion bonding can be performed even if the thickness is 2 mm or less. However, when the highly conductive metal thin plate W3 is too thick compared to the first workpiece W1 and the second workpiece W2, the following problems occur. For example, in the case where the highly conductive thin metal sheet W3 has a thickness larger than the thickness of the first workpiece W1 or the second workpiece W2, the projection P1 and the high conductivity due to the energization of the pulse welding current. Heat generation due to the first contact resistance at the contact portion with the metal thin plate W3 and heat generation due to the second contact resistance at the contact portion between the projection P2 and the highly conductive metal thin plate W3 are compared with the energization time of the pulse welding current. Since the heat conduction speed is slow, both the heat generations are conducted in the thickness inward direction of the highly conductive thin metal sheet W3 during the energization of the pulsed welding current. The temperature rise at the contact portion between P1 and the highly conductive metal thin plate W3 becomes insufficient, and therefore the plastic fluidization of the contact portion becomes incomplete. Similarly, the plastic fluidization at the contact portion between the projection P2 and the highly conductive thin metal plate W3 is also incomplete, so that the welding strength is reduced. In order to solve this problem, the peak value of the pulsed welding current must be further increased.

しかし、パルス状溶接電流のピーク値を大きくすれば大きくするほど、溶接電極1と第1の被溶接物W1との当接面及び第2の被溶接物W2と溶接電極2との当接面での発熱が大きくなり、溶接電極1に第1の被溶接物W1が付着し易くなり、また溶接電極2に第2の被溶接物W2が付着し易くなるために溶接電極1、2が汚れるという問題が生じる。つまり、大きな溶接電力を使用した上で、頻繁に溶接電極のクリーニングなどを行わなければならなくなる問題を生ずる。したがって、パルス状溶接電流の通電時間と高導電性金属薄板W3の熱伝導などの関係から、高導電性金属薄板W3は第1の被溶接物W1又は第2の被溶接物W2の厚み以下の厚みであることが好ましい。例えば、第1の被溶接物W1及び第2の被溶接物W2の厚みが数mmであれば、高導電性金属薄板W3が1mm程度以下の厚みのときには、第1の被溶接物W1と高導電性金属薄板W3と第2の被溶接物W2の三者を十分に満足に行く拡散接合を行えるので、高導電性金属薄板W3の厚みは、1mm程度以下の厚みの薄板であることが好ましい。   However, as the peak value of the pulse welding current is increased, the contact surface between the welding electrode 1 and the first workpiece W1 and the contact surface between the second workpiece W2 and the welding electrode 2 are increased. The first electrode W1 is likely to adhere to the welding electrode 1 and the second workpiece W2 is likely to adhere to the welding electrode 2, so that the welding electrodes 1 and 2 become dirty. The problem arises. That is, there arises a problem that the welding electrode needs to be frequently cleaned after using a large welding power. Therefore, from the relationship between the energization time of the pulse welding current and the heat conduction of the highly conductive thin metal sheet W3, the highly conductive thin metal sheet W3 is equal to or less than the thickness of the first workpiece W1 or the second welded object W2. Thickness is preferred. For example, if the thickness of the first workpiece W1 and the second workpiece W2 is several mm, the thickness of the first workpiece W1 and the height of the first workpiece W1 is high when the highly conductive thin metal sheet W3 has a thickness of about 1 mm or less. Since the diffusion joining which can sufficiently satisfy the three of the conductive metal thin plate W3 and the second workpiece W2 can be performed, the thickness of the high conductive metal thin plate W3 is preferably a thin plate having a thickness of about 1 mm or less. .

すなわち、第1の被溶接物W1のプロジェクションP1と高導電性金属薄板W3との間の接触抵抗、及び第2の被溶接物W2のプロジェクションP2と高導電性金属薄板W3との間の接触抵抗を利用することによって、高導電性被溶接物同士の接合では不足する発熱量を補うことができればよい。したがって、高導電性金属薄板W3は1μm程度以上あればよい。また、高導電性金属薄板W3の幅と長さを使用目的に応じて設定することによって、第3の被溶接物として利用することができる。   That is, the contact resistance between the projection P1 of the first workpiece W1 and the highly conductive metal thin plate W3, and the contact resistance between the projection P2 of the second workpiece W2 and the high conductive metal thin plate W3. It is only necessary to compensate for the calorific value that is insufficient in the joining of the highly conductive workpieces by using. Therefore, the highly conductive metal thin plate W3 may be about 1 μm or more. Moreover, it can utilize as a 3rd to-be-welded object by setting the width | variety and length of the highly conductive metal thin plate W3 according to the intended purpose.

この実施形態1では、第1、第2の被溶接物W1、W2及び高導電性金属薄板W3が銅部材からなるものとして説明したが、高導電性金属薄板W3がアルミニウム材からなってもプロジェクション溶接ができるが、溶接強度が幾分低下する場合もあるので、高導電性金属薄板W3は銅部材からなるのが好ましい。第1、第2の被溶接物W1、W2はアルミニウム材からなっても勿論よい。この場合には、高導電性金属薄板W3はアルミニウム材又は銅部材のどちらからなってもよいが、プロジェクション溶接の簡便性からはアルミニウム材からなる高導電性金属薄板W3を用いた方が望ましい。また、第1、第2の被溶接物W1、W2の一方が銅部材、他方がアルミニウム部材からなっても同様にしてプロジェクション溶接を行うことができ、この場合、高導電性金属薄板W3は銅部材からなるのが好ましいが、アルミニウム部材からなってもよい。なお、本発明のプロジェクション溶接方法を実現する抵抗溶接装置については、各実施形態を説明した後で図8によって簡単に説明する。なお、プロジェクションP1、P2は、1点又は多点のプロジェクション、あるいは、一般的な形状のリングプロジェクションであってもよく、プロジェクションの形状には制限されない。   In the first embodiment, the first and second workpieces W1 and W2 and the highly conductive thin metal plate W3 are described as being made of a copper member. However, even if the highly conductive thin metal plate W3 is made of an aluminum material, the projection is performed. Although welding can be performed, the weld strength may be somewhat reduced, so the highly conductive thin metal sheet W3 is preferably made of a copper member. Of course, the first and second workpieces W1 and W2 may be made of an aluminum material. In this case, the highly conductive thin metal plate W3 may be made of either an aluminum material or a copper member, but it is desirable to use the highly conductive thin metal plate W3 made of an aluminum material for the convenience of projection welding. Further, even if one of the first and second workpieces W1 and W2 is a copper member and the other is an aluminum member, projection welding can be performed in the same manner. In this case, the highly conductive thin metal plate W3 is made of copper. It is preferably made of a member, but may be made of an aluminum member. In addition, about the resistance welding apparatus which implement | achieves the projection welding method of this invention, after describing each embodiment, it demonstrates easily with FIG. The projections P1 and P2 may be single-point or multi-point projections or ring projections having a general shape, and are not limited to the shape of the projection.

[実施形態2]
図2によって本発明に係るプロジェクション溶接方法の実施形態2について説明する。図2において、図1で用いた記号と同一の記号は同じ名称の部材を示すものとする。第1の被溶接物W1は銅部材からなり、その一方の面側にプロジェクションP1が形成されている。同様に、第2の被溶接物W2も銅部材からなり、その一方の面側にプロジェクションP2が形成されている。高導電性金属薄板W3は4枚の銅箔wを重ねたものからなる。例えば、それぞれの銅箔wは100μm程度の厚みを有し、したがって、高導電性金属薄板W3は400μm程度の厚みを有する。実施形態2における高導電性金属薄板W3は、使用目的に適した所定の幅と長さを有する第3の被溶接物となる。実施形態2においても、溶接電極1を流れるパルス状溶接電流は、先ず溶接電極1と第1の被溶接物W1との当接面から第1の被溶接物W1を通してプロジェクションP1に集中し、プロジェクションP1に当接している高導電性金属薄板W3の一方の当接面域の第1の接触抵抗を通して高導電性金属薄板W3内に流れる。更に、パルス状溶接電流はプロジェクションP2に当接している高導電性金属薄板W3の他方の当接面域の第2の接触抵抗に集中し、第2の被溶接物W2、及び第2の被溶接物W2と溶接電極2との当接面から溶接電極2へと流れる。
[Embodiment 2]
Embodiment 2 of the projection welding method according to the present invention will be described with reference to FIG. 2, the same symbols as those used in FIG. 1 indicate members having the same names. The first workpiece W1 is made of a copper member, and a projection P1 is formed on one surface side thereof. Similarly, the second workpiece W2 is also made of a copper member, and a projection P2 is formed on one surface side thereof. The highly conductive metal thin plate W3 is formed by stacking four copper foils w. For example, each copper foil w has a thickness of about 100 μm, and thus the highly conductive thin metal sheet W3 has a thickness of about 400 μm. The highly conductive metal thin plate W3 in the second embodiment is a third workpiece to be welded having a predetermined width and length suitable for the intended use. Also in the second embodiment, the pulsed welding current flowing through the welding electrode 1 first concentrates on the projection P1 through the first workpiece W1 from the contact surface between the welding electrode 1 and the first workpiece W1. It flows in the highly conductive metal thin plate W3 through the first contact resistance in one contact surface area of the high conductive metal thin plate W3 in contact with P1. Further, the pulsed welding current is concentrated on the second contact resistance of the other contact surface area of the highly conductive thin metal sheet W3 that is in contact with the projection P2, and the second workpiece W2 and the second workpiece to be welded are concentrated. It flows from the contact surface between the weldment W2 and the welding electrode 2 to the welding electrode 2.

プロジェクションP1に当接している最上位の高導電性金属薄板W3の銅箔wと第1の被溶接物W1とは前述したようにプロジェクション溶接が行われ、また、プロジェクションP2に当接している最下位の高導電性金属薄板W3の銅箔wと第2の被溶接物W2とは前述したようにプロジェクション溶接が行われる。しかし、隣り合う銅箔w同士はほぼ全面で当接しているから当接面が広く、厚みが大きいと溶接電流は横方向に広がり易くなるので、隣り合う銅箔w同士の当接面を流れる溶接電流は、プロジェクションP1とP2とを最短距離で結ぶ4枚の銅箔wの電流路における電流密度が最も大きく、それを離れるに従って小さくなる。   The copper foil w of the uppermost highly conductive thin metal sheet W3 that is in contact with the projection P1 and the first workpiece W1 are subjected to projection welding as described above, and are the most in contact with the projection P2. As described above, projection welding is performed on the copper foil w of the lower high-conductivity metal thin plate W3 and the second workpiece W2. However, since the adjacent copper foils w are almost in contact with each other, the contact surface is wide, and if the thickness is large, the welding current easily spreads in the lateral direction, and therefore flows through the contact surfaces of the adjacent copper foils w. The welding current has the highest current density in the current path of the four copper foils w connecting the projections P1 and P2 with the shortest distance, and the welding current decreases as the distance is increased.

しかしながら、隣り合う銅箔w同士の当接面にそれぞれ接触抵抗が生じるので、発熱が大きくなり、1枚の銅箔wの厚みが例えばほぼ500μm以下ならば、横方向に流れる電流を小さく抑えることができると同時に、前述したようにそれぞれの当接面の接触抵抗によって生じる発熱がパルス状溶接電流の通電期間に互いに隣り合う当接面まで熱伝導されるので、少なくともプロジェクションP1とP2とを最短距離で結ぶ4枚の銅箔wの電流路及びその近傍部分では塑性流動化が生じ、隣り合う銅箔w同士の当接面それぞれにおいても望ましい拡散接合が行われる。したがって、第1、第2の被溶接物1、2は銅箔wを重ねた高導電性金属薄板W3を介してもプロジェクション溶接することができる。   However, since contact resistance is generated between the contact surfaces of the adjacent copper foils w, heat generation increases, and if the thickness of one copper foil w is, for example, approximately 500 μm or less, the current flowing in the lateral direction is kept small. At the same time, as described above, the heat generated by the contact resistance of each contact surface is thermally conducted to the contact surfaces adjacent to each other during the energization period of the pulse welding current, so that at least the projections P1 and P2 are minimized. Plastic fluidization occurs in the current paths of the four copper foils w connected by the distance and in the vicinity thereof, and desirable diffusion bonding is performed also on each contact surface between the adjacent copper foils w. Accordingly, the first and second workpieces 1 and 2 can be projection welded via the highly conductive thin metal sheet W3 on which the copper foil w is superimposed.

実施形態2では、高導電性金属薄板W3としての4枚の銅箔wを重ねた薄板を用いたが、これに制限されるものではない。ただし、銅箔wを重ねる枚数が増えると、その分だけ当接面が増え、接触抵抗も増えるが、接触抵抗が増える分、銅箔wを横方向に流れる電流も増えるので、重ねられた銅箔wの内、中央部に位置する銅箔wほど電流密度が低下する傾向がある。したがって、パルス状溶接電流のピーク値などの条件によっても異なるが、一例としては得られる溶接強度の面から銅箔wを重ねた厚みをほぼ1mm程度以内に制限するのが好ましい。この場合、例えば、100μmの銅箔wを重ねる場合には、10枚以下に制限するのが望ましい。   In Embodiment 2, although the thin plate which piled up four copper foil w as the highly conductive metal thin plate W3 was used, it is not restrict | limited to this. However, as the number of stacked copper foils w increases, the contact surface increases and the contact resistance also increases. However, as the contact resistance increases, the current flowing in the lateral direction of the copper foil w also increases. Of the foil w, the copper foil w located at the center tends to decrease the current density. Therefore, although depending on conditions such as the peak value of the pulse-shaped welding current, as an example, it is preferable to limit the thickness of the overlapped copper foil w to about 1 mm or less in terms of the obtained welding strength. In this case, for example, when stacking 100 μm copper foils w, it is desirable to limit the number to 10 or less.

この実施形態2において、ある厚みの銅箔w、例えば10μm程度以下の厚みの銅箔wを複数枚重ねた高導電性金属薄板W3を用いる場合には、銅箔w間を流れる電流密度の減少に比べて接触抵抗の増大による発熱効果が大きくなるので、高導電性金属薄板W3による発熱が増大し、より拡散接合を容易に行える。このことは高導電性金属薄板W3の存在による効果をより大きなものにし、パルス状溶接電流のピーク値を小さくすることが可能であり、被溶接物の付着による溶接電極の汚れを少なくできる。なお、第1、第2の被溶接物W1、W2はアルミニウム材からなっても勿論よい。この場合には、高導電性金属薄板W3はアルミニウム材又は銅部材のどちらからなってもよく、ほぼ同じ溶接強度を得ることができる。プロジェクションP1、P2は、1点又は多点のプロジェクション、あるいは、一般的な形状のリングプロジェクションであってもよく、プロジェクションの形状には制限されない。   In the second embodiment, when a highly conductive thin metal sheet W3 in which a plurality of copper foils w having a thickness of, for example, a thickness of about 10 μm or less is used is used, the current density flowing between the copper foils w is reduced. Compared with the above, since the heat generation effect due to the increase in contact resistance is increased, the heat generation due to the highly conductive metal thin plate W3 is increased, and diffusion bonding can be performed more easily. This increases the effect of the presence of the highly conductive thin metal sheet W3, can reduce the peak value of the pulsed welding current, and can reduce contamination of the welding electrode due to adhesion of the workpiece. Of course, the first and second workpieces W1 and W2 may be made of an aluminum material. In this case, the highly conductive metal thin plate W3 may be made of either an aluminum material or a copper member, and can obtain substantially the same welding strength. The projections P1 and P2 may be single-point or multi-point projections or ring projections having a general shape, and are not limited to the shape of the projection.

[実施形態3]
図2によって本発明に係るプロジェクション溶接方法の実施形態3について説明する。この実施形態3では、第1の被溶接物W1が銅部材からなり、第2の被溶接物W2がアルミニウム部材からなる。この場合には、図2において、高導電性金属薄板W3を構成する上側2枚の箔wは銅材からなり、下側の2枚の箔wはアルミニウム材からなる。この場合にもほぼ前述と同様に抵抗溶接できるが、銅に比べてアルミニウムの融点は低い、つまり塑性流動化する温度が低いので、それらの融点の比率に反比例するよう、第1の被溶接物WIの頂部の面積、つまり第1の被溶接物WIの頂部と高導電性金属薄板W3との当接面積に比べて、第2の被溶接物W2の頂部と高導電性金属薄板W3との当接面積を大きくすれば、前者の電流密度が後者の電流密度よりも大きくなるから、より良好な接合結果を得ることができる。
[Embodiment 3]
Embodiment 3 of the projection welding method according to the present invention will be described with reference to FIG. In the third embodiment, the first workpiece W1 is made of a copper member, and the second workpiece W2 is made of an aluminum member. In this case, in FIG. 2, the upper two foils w constituting the highly conductive thin metal sheet W3 are made of a copper material, and the lower two foils w are made of an aluminum material. In this case as well, resistance welding can be performed in substantially the same manner as described above. However, since the melting point of aluminum is lower than that of copper, that is, the temperature at which plastic fluidization occurs is low, the first workpiece to be welded is inversely proportional to the ratio of these melting points Compared to the area of the top of WI, that is, the contact area between the top of the first workpiece WI and the highly conductive metal thin plate W3, the top of the second workpiece W2 and the high conductive metal thin plate W3 If the contact area is increased, the former current density is larger than the latter current density, so that a better bonding result can be obtained.

上側2枚の銅箔wと下側の2枚のアルミニウム箔wとの接合についても、塑性流動化の始まりに微少の時間的ずれが生じるが、銅箔w、アルミニウム箔wの双方が塑性流動化して満足できる拡散接合が行われる。また、銅箔w、アルミニウム箔wの枚数は異なってもよく、例えば、銅箔wが3枚でアルミニウム箔wが1枚であってもよい。高導電性金属薄板W3の厚みの条件は実施形態1、2と同じである。この実施形態3においても、実施形態2と同様に、ある厚みの銅箔wとアルミニウム箔w、例えば10μm程度以下の厚みの銅箔wとアルミニウム箔wを複数枚重ねた高導電性金属薄板W3を用いる場合には、銅箔w、アルミニウム箔w間を流れる電流密度の減少に比べて接触抵抗の増大による発熱効果が大きくなるので、高導電性金属薄板W3による発熱が増大し、より拡散接合を容易に行える。このことは高導電性金属薄板W3の存在による効果をより大きなものにし、パルス状溶接電流のピーク値を小さくすることが可能であり、被溶接物の付着による溶接電極の汚れを少なくできる。   Even when the upper two copper foils w and the lower two aluminum foils w are joined, a slight time lag occurs at the beginning of plastic fluidization, but both the copper foil w and the aluminum foil w are plastically flowed. To achieve satisfactory diffusion bonding. The number of copper foils w and aluminum foils w may be different, for example, three copper foils w and one aluminum foil w may be used. The conditions for the thickness of the highly conductive metal thin plate W3 are the same as those in the first and second embodiments. Also in the third embodiment, as in the second embodiment, a copper foil w and aluminum foil w having a certain thickness, for example, a highly conductive metal thin plate W3 in which a plurality of copper foils w and aluminum foil w having a thickness of about 10 μm or less are stacked. Is used, the heat generation effect due to the increase in contact resistance is larger than the decrease in the current density flowing between the copper foil w and the aluminum foil w, so the heat generation due to the highly conductive thin metal sheet W3 is increased and the diffusion bonding is further performed. Can be easily performed. This increases the effect of the presence of the highly conductive thin metal sheet W3, can reduce the peak value of the pulsed welding current, and can reduce contamination of the welding electrode due to adhesion of the workpiece.

[実施形態4]
図3によって本発明に係るプロジェクション溶接方法の実施形態4について説明する。図3において、図1、図2で用いた記号と同一の記号は同じ名称の部材を示すものとする。第1の被溶接物W1、第2の被溶接物W2は銅部材からなり、高導電性金属薄板W3も銅部材からなる。この実施形態3は、第1、第2の被溶接物W1、W2の厚みなどの関係から被溶接物W1、W2にプロジェクションを形成してもプロジェクションの役割を十分に果たし難い場合、あるいは被溶接物W1、W2にプロジェクションを形成したくない場合などに特に有用である。したがって、第1の被溶接物W1、第2の被溶接物W2にはプロジェクションが形成されておらず、高導電性金属薄板W3の両面にプロジェクションP3、P4がそれぞれ形成されている。高導電性金属薄板W3の厚みは、前述のように、第1の被溶接物W1又は第2の被溶接物W2の厚み以下の厚みが好ましい。また、プロジェクションP3、P4は前述したプロジェクションP1、P2と同様なものである。高導電性金属薄板W3は使用目的の用途に適う形状、幅、長さなどを有する。
[Embodiment 4]
Embodiment 4 of the projection welding method according to the present invention will be described with reference to FIG. In FIG. 3, the same symbols as those used in FIGS. 1 and 2 indicate members having the same names. The first workpiece W1 and the second workpiece W2 are made of a copper member, and the highly conductive metal thin plate W3 is also made of a copper member. In the third embodiment, when the projections are formed on the workpieces W1 and W2 due to the thicknesses of the first and second workpieces W1 and W2, it is difficult to fulfill the role of projection, or the welding is performed. This is particularly useful when it is not desired to form a projection on the objects W1 and W2. Therefore, no projection is formed on the first workpiece W1 and the second workpiece W2, and projections P3 and P4 are formed on both surfaces of the highly conductive thin metal plate W3. As described above, the thickness of the highly conductive metal thin plate W3 is preferably equal to or less than the thickness of the first workpiece W1 or the second workpiece W2. The projections P3 and P4 are the same as the projections P1 and P2 described above. The highly conductive metal thin plate W3 has a shape, width, length and the like suitable for the intended use.

前述したようなパルス状の溶接電流は、図3において、第1の被溶接物W1の下面と高導電性金属薄板W3のプロジェクションP3との微小な当接面の第1の接触抵抗、及び高導電性金属薄板W3のプロジェクションP4と第2の被溶接物W2の上面との微小な当接面の第2の接触抵抗を集中して流れ、これら接触抵抗による発熱でそれら当接部分が塑性流動化することにより良好な拡散接合が行われる。したがって、第1の被溶接物W1と第2の被溶接物W2と高導電性金属薄板W3の3者は所期の溶接強度で互いにプロジェクション溶接される。高導電性金属薄板W3はプロジェクションP3、P4に相当するプロジェクションをそれぞれ有する銅板を2枚重ね合わせたものであってもよい。それら銅板は加圧力によってプロジェクションが圧潰されない程度以上の厚みをもっていればよく、それら銅板の間に銅箔が挟まれていても勿論よい。なお、実施形態3においても、第1の被溶接物W1、第2の被溶接物W2がアルミニウムからなる場合には、高導電性金属薄板W3はアルミニウム材からなるのが好ましいが、銅材からなってもよい。第1の被溶接物W1、第2の被溶接物W2の一方が銅材、他方がアルミニウム材からなる場合には高導電性金属薄板W3は銅材からなるのが好ましいが、アルミニウム材からなってもよい。   In FIG. 3, the pulse-like welding current as described above includes the first contact resistance of the minute contact surface between the lower surface of the first workpiece W1 and the projection P3 of the highly conductive metal thin plate W3, and the high The second contact resistance of the minute contact surface between the projection P4 of the conductive metal thin plate W3 and the upper surface of the second workpiece W2 flows in a concentrated manner, and the heat generated by these contact resistance causes the contact portion to plastically flow. As a result, good diffusion bonding is performed. Therefore, the three members, that is, the first workpiece W1, the second workpiece W2, and the highly conductive thin metal plate W3 are projection-welded to each other with a predetermined welding strength. The highly conductive metal thin plate W3 may be a laminate of two copper plates each having a projection corresponding to the projections P3 and P4. These copper plates need only have a thickness that does not cause the projection to be crushed by the applied pressure. Of course, a copper foil may be sandwiched between the copper plates. In Embodiment 3 also, when the first workpiece W1 and the second workpiece W2 are made of aluminum, the highly conductive thin metal plate W3 is preferably made of an aluminum material, but from a copper material. It may be. When one of the first workpiece W1 and the second workpiece W2 is made of a copper material and the other is made of an aluminum material, the highly conductive thin metal plate W3 is preferably made of a copper material, but is made of an aluminum material. May be.

[実施形態5]
図4によって本発明に係るプロジェクション溶接方法の実施形態5について説明する。図4において、図1〜図3で用いた記号と同一の記号は同じ名称の部材を示すものとする。実施形態5は、銅製の円環状パイプである第1の被溶接物W1と銅製の円環状パイプである第2の被溶接物W2とを、円環状の高導電性金属薄板W3を介して突合せ溶接する実施例である。第1の被溶接物W1の端部は先細りとなるように切削されてリング状のプロジェクションP1が形成されている。また、第2の被溶接物W2の端部も同様に先細りとなるように切削されてリング状のプロジェクションP2が形成されている。これら円環状パイプはほぼ等しい外径、内径を有する。リング状のプロジェクションP1とリング状のプロジェクションP2との間に位置する円環状の高導電性金属薄板W3は、前記環状のパイプの外径と内径とにほぼ等しい外径、内径であって、前述したように高導電性金属薄板W3の厚みは、前述のように、第1の被溶接物W1又は第2の被溶接物W2の厚み以下の厚みが好ましい。
[Embodiment 5]
Embodiment 5 of the projection welding method according to the present invention will be described with reference to FIG. In FIG. 4, the same symbols as those used in FIGS. 1 to 3 indicate members having the same names. In the fifth embodiment, a first workpiece W1 that is a copper annular pipe and a second workpiece W2 that is a copper annular pipe are butt-joined via an annular highly conductive thin metal plate W3. It is the Example welded. The end of the first workpiece W1 is cut so as to be tapered to form a ring-shaped projection P1. Similarly, the end of the second workpiece W2 is cut so as to be tapered to form a ring-shaped projection P2. These annular pipes have substantially the same outer diameter and inner diameter. An annular high-conductivity thin metal plate W3 located between the ring-shaped projection P1 and the ring-shaped projection P2 has an outer diameter and an inner diameter that are substantially equal to the outer diameter and the inner diameter of the annular pipe. As described above, the thickness of the highly conductive metal thin plate W3 is preferably equal to or less than the thickness of the first workpiece W1 or the second workpiece W2 as described above.

溶接電極1、2は一般の鋼管を抵抗溶接するときに用いられる一般的なコレットチャック構造のものであるので詳しく説明しないが、溶接電極1、2は縦方向に複数に分割、例えば3個の電極部に分割されており、これら3個の電極部が前記銅製の円環状パイプの中心軸線Xに対して放射内方向、放射外方向に動くことによって、前記銅製の円環状パイプを把持、開放するものである。実施形態5では、第1の被溶接物W1と第2の被溶接物W2との間に円環状の高導電性金属薄板W3を正確に位置させ、保持するために保持機構HMを備える。保持機構HMは等間隔、例えば120度間隔で設けられた支持部材M1、M2(他の1個の支持部材は陰になっているので示されていない。)とこれらを駆動する不図示の駆動機構などからなる。支持部材M1、M2などは、第1の被溶接物W1と第2の被溶接物W2との間に円環状の高導電性金属薄板W3が配置される前には、前記中心軸線Xに対して放射外方向に後退しており、第1の被溶接物W1と第2の被溶接物W2との間に円環状の高導電性金属薄板W3が配置されると、前記中心軸線Xに対して放射内方向に前進して、第1の被溶接物W1と第2の被溶接物W2のごく先端部分と円環状の高導電性金属薄板W3の外周面に当接し、その状態を保持するものである。   Since the welding electrodes 1 and 2 have a general collet chuck structure used when resistance welding a general steel pipe, they will not be described in detail, but the welding electrodes 1 and 2 are divided into a plurality of parts in the vertical direction, for example, three Divided into electrode parts, these three electrode parts move radially inward and outward with respect to the central axis X of the copper annular pipe to grip and open the copper annular pipe. To do. In the fifth embodiment, a holding mechanism HM is provided for accurately positioning and holding the annular high-conductivity metal thin plate W3 between the first workpiece W1 and the second workpiece W2. The holding mechanism HM has support members M1 and M2 (not shown because the other one support member is shaded) provided at regular intervals, for example, 120 ° intervals, and a drive (not shown) that drives them. It consists of mechanisms. The supporting members M1, M2, etc. are arranged with respect to the central axis X before the annular highly conductive metal thin plate W3 is disposed between the first workpiece W1 and the second workpiece W2. If the annular highly conductive thin metal plate W3 is disposed between the first workpiece W1 and the second workpiece W2, the center axis X is retracted. Then, it advances forward in the radial direction and comes into contact with the very distal end portions of the first workpiece W1 and the second workpiece W2 and the outer peripheral surface of the annular high-conductivity thin metal plate W3, and maintains this state. Is.

次に、プロジェクション溶接方法の一例について説明する。従来と同様に、溶接電極1に第1の被溶接物W1を、また、溶接電極2に第2の被溶接物W2をそれぞれ把持させる。第2の被溶接物W2である円環状パイプのリング状のプロジェクションP2上に、円環状の高導電性金属薄板W3を供給する。次に、溶接電極1を下降、又は溶接電極2を上昇させて、第1の被溶接物W1である円環状パイプのリング状のプロジェクションP1を円環状の高導電性金属薄板W3の上面に軽く接触させる。次に、保持機構HMが動作し、支持部材M1、M2などを前記中心軸線Xに対して放射内方向に前進させ、第1の被溶接物W1と第2の被溶接物W2のごく先端部分と円環状の高導電性金属薄板W3の外周面に当接して、位置ずれなどを修正し、その状態を保持する。   Next, an example of the projection welding method will be described. As in the prior art, the welding object 1 is made to hold the first work piece W1 and the welding electrode 2 is made to hold the second work piece W2. An annular highly conductive thin metal sheet W3 is supplied onto the ring-shaped projection P2 of the annular pipe which is the second workpiece W2. Next, the welding electrode 1 is lowered or the welding electrode 2 is raised, and the ring-shaped projection P1 of the annular pipe, which is the first workpiece W1, is lightly applied to the upper surface of the annular highly conductive thin metal plate W3. Make contact. Next, the holding mechanism HM is operated to advance the support members M1, M2 and the like in the radial inward direction with respect to the central axis X, so that the very distal end portions of the first workpiece W1 and the second workpiece W2 are welded. And abutting against the outer peripheral surface of the annular highly conductive metal thin plate W3, the positional deviation is corrected and the state is maintained.

次に、溶接電極1と2との間に加圧力がかけられると、支持部材M1、M2などが後退し始め、しかる後にパルス状溶接電流が通電される。前述と同様に、プロジェクションP1と高導電性金属薄板W3との当接面の第1の接触抵抗による発熱でプロジェクション溶接が行われ、かつプロジェクションP2と高導電性金属薄板W3との当接面での第2の接触抵抗による発熱でプロジェクション溶接が行われることによって、高導電性金属薄板W3を介して第1の被溶接物W1と第2の被溶接物W2とのプロジェクション溶接が行われる。この溶接方法によれば、高導電性金属薄板W3の位置の修正もできると共に、位置を修正した状態を保持でき、しかも溶接電流の通電前に支持部材M1、M2などが後退するので、支持部材M1、M2などが汚損する危険性もない。   Next, when a pressing force is applied between the welding electrodes 1 and 2, the support members M1, M2 and the like begin to move backward, and then a pulsed welding current is applied. Similarly to the above, projection welding is performed by the heat generated by the first contact resistance of the contact surface between the projection P1 and the highly conductive metal thin plate W3, and at the contact surface between the projection P2 and the high conductive metal thin plate W3. By performing projection welding with the heat generated by the second contact resistance, projection welding of the first workpiece W1 and the second workpiece W2 is performed via the highly conductive metal thin plate W3. According to this welding method, the position of the highly conductive thin metal sheet W3 can be corrected, the corrected position can be maintained, and the supporting members M1, M2 and the like are retracted before energization of the welding current. There is no risk of M1, M2, etc. being soiled.

なお、第1の被溶接物W1と第2の被溶接物W2との端部にリング状のプロジェクションP1、P2を設けずに、高導電性金属薄板W3の両面にリングプロジェクションを設けてあっても勿論よい。この場合には、被溶接物にプロジェクションを形成する工程を省くことができ、有利である。また、円環状の高導電性金属薄板W3の外径は第1、第2の被溶接物W1、W2である円環状パイプの外径、内径と条件によっては同じである必要はなく、また、高導電性金属薄板W3は円環状の銅箔を必要枚数重ねたもの、あるいは網状のものであってもよい。第1、第2の被溶接物W1、W2はアルミニウム製のパイプであってもよく、この場合には環状の高導電性金属薄板W3は好ましくはアルミニウム材からなり、銅材からなっても良い。また、第1、第2の被溶接物W1、W2の一方が銅製のパイプで、他方がアルミニウム製のパイプであってもよく、この場合には高導電性金属薄板W3が両面にリングプロジェクションを有する銅製のもの、あるいは円環状の銅箔と円環状のアルミニウムの箔とを重ねたものであってもよい。   The ring projections P1 and P2 are not provided at the ends of the first workpiece W1 and the second workpiece W2, but ring projections are provided on both surfaces of the highly conductive thin metal plate W3. Of course. In this case, it is possible to omit the step of forming the projection on the workpiece, which is advantageous. In addition, the outer diameter of the annular highly conductive metal thin plate W3 does not need to be the same depending on the outer diameter, inner diameter and conditions of the annular pipe which is the first and second workpieces W1 and W2, The highly conductive metal thin plate W3 may be a laminate of a necessary number of annular copper foils or a net-like one. The first and second workpieces W1 and W2 may be aluminum pipes. In this case, the annular highly conductive thin metal plate W3 is preferably made of an aluminum material and may be made of a copper material. . In addition, one of the first and second workpieces W1 and W2 may be a copper pipe and the other may be an aluminum pipe. In this case, the highly conductive thin metal plate W3 performs ring projection on both sides. It may be made of copper or an annular copper foil and an annular aluminum foil laminated.

なお、実施形態5では第1、第2の被溶接物W1、W2が銅製又はアルミニウム製のパイプとして説明したが、銅製又はアルミニウム製の円柱などであっても同様に良好なプロジェクション溶接結果が得られる。第1、第2の被溶接物W1、W2が銅製又はアルミニウム製の円柱の場合には、高導電性金属薄板W3は銅製又はアルミニウム製の円板でよい。更にまた、以上の実施形態では高導電性金属薄板W3が存在することの作用、効果について述べたが、高導電性金属薄板W3が溶接時の加圧力で曲がり難い程度の厚みである100μm程度以上の厚みを有していれば、第1、第2の被溶接物W1、W2のプロジェクションP1、P2の頂部の位置合わせが多少ずれていたとしても、何らの支障を起こすことなく簡便に拡散接合を行うことができるという効果を奏する。このことは実際の製造ラインではプロジェクションP1、P2の頂部同士の厳密な位置合わせとその状態を厳密に保持しながら溶接を行わなくてもよいという面で非常に有利である。   In the fifth embodiment, the first and second workpieces W1 and W2 have been described as copper or aluminum pipes, but good projection welding results are obtained even when the cylinders are made of copper or aluminum. It is done. When the first and second workpieces W1 and W2 are cylindrical columns made of copper or aluminum, the highly conductive thin metal plate W3 may be a copper or aluminum disc. Furthermore, in the above embodiment, the operation and effect of the presence of the highly conductive metal thin plate W3 have been described. However, the thickness of the high conductive metal thin plate W3 is about 100 μm or more which is difficult to bend by the applied pressure during welding. If the thickness of the projections P1 and P2 of the first and second workpieces W1 and W2 is slightly misaligned, diffusion bonding can be easily performed without causing any trouble. There is an effect that can be performed. In an actual production line, this is very advantageous in terms of strict alignment between the tops of the projections P1 and P2 and the need to perform welding while strictly maintaining the state.

[実施形態6]
図5〜図6によって本発明に係るプロジェクション溶接方法の実施形態6について説明する。図5〜図6において、図1〜図4で用いた記号と同一の記号は同じ名称の部材を示すものとする。図5は通電前における第1の高導電性被溶接物W1と第2の高導電性被溶接W2の一部分の断面とそれらに挟まれた高導電性金属薄板W3の拡散接合時における変形などを説明するために拡大して示す図である。実施形態6は、実施形態2における第1の高導電性被溶接物W1と第2の高導電性被溶接W2にそれぞれ形成されたプロジェクションP1、P2は円環状、つまりリング状のプロジェクションであって、高導電性金属薄板W3が曲がり易い厚み、例えば数μmないし10μm程度の肉厚の銅箔wを4、5枚ないしは数十枚重ねたものからなる場合について説明する。ここでは高導電性金属箔wを銅箔として説明するが、アルミニウムなど他の高導電性金属箔であっても勿論よい。前述したように、プロジェクションP1、P2は通常のリングプロジェクションでよい。
[Embodiment 6]
Embodiment 6 of the projection welding method according to the present invention will be described with reference to FIGS. 5 to 6, the same symbols as those used in FIGS. 1 to 4 indicate members having the same names. FIG. 5 shows a partial cross section of the first highly conductive workpiece W1 and the second highly conductive workpiece W2 before energization and deformation during diffusion bonding of the highly conductive metal thin plate W3 sandwiched between them. It is a figure expanded and shown in order to demonstrate. In the sixth embodiment, the projections P1 and P2 respectively formed on the first highly conductive workpiece W1 and the second highly conductive workpiece W2 in the second embodiment are annular, that is, ring-shaped projections. A case will be described in which the highly conductive thin metal sheet W3 is formed of a stack of four, five, or several tens of copper foils w having a thickness that can be easily bent, for example, about several μm to 10 μm. Here, the highly conductive metal foil w will be described as a copper foil, but other highly conductive metal foils such as aluminum may of course be used. As described above, the projections P1 and P2 may be normal ring projections.

図5及び図6に示す第1の高導電性被溶接物W1は、リング状のプロジェクションP1に囲まれた部分に凹所V1を有するとともに、リング状のプロジェクションP1の外側近傍に円環状の凹所V2を有する。凹所V1は、リング状のプロジェクションP1の直径が小さい場合には小円筒状の凹所であり、リング状のプロジェクションP1の直径が大きい場合にはプロジェクションP1の内側に沿った円環状の凹所であってもよい。第2の高導電性被溶接物W2も、リング状のプロジェクションP2に囲まれた部分に凹所V1と同様な凹所V3を有するとともに、リング状のプロジェクションP2の周囲に沿って凹所V2と同様な円環状の凹所V4を有する。   The first highly conductive work W1 shown in FIGS. 5 and 6 has a recess V1 in a portion surrounded by the ring-shaped projection P1, and an annular recess near the outside of the ring-shaped projection P1. It has a place V2. The recess V1 is a small cylindrical recess when the diameter of the ring-shaped projection P1 is small, and the annular recess along the inside of the projection P1 when the diameter of the ring-shaped projection P1 is large. It may be. The second highly conductive work W2 also has a recess V3 similar to the recess V1 in the portion surrounded by the ring-shaped projection P2, and the recess V2 along the periphery of the ring-shaped projection P2. A similar annular recess V4 is provided.

拡散接合に当たって、高導電性金属薄板W3の最上位に位置する銅箔wの上面に第1の高導電性被溶接物W1のリング状のプロジェクションP1の頂面が当接され、高導電性金属薄板W3の最下位に位置する銅箔wの下面に第2の高導電性被溶接物W1のリング状のプロジェクションP2の頂面が当接される。その状態で図示しない加圧機構によって溶接電極1、2の間に加圧力がかけられ、通常は加圧力が増大する過程で所定の値を通過するとき、急峻に立上る接合電流が溶接電極1、2間を流れる。   At the time of diffusion bonding, the top surface of the ring-shaped projection P1 of the first highly conductive work piece W1 is brought into contact with the upper surface of the copper foil w positioned at the uppermost position of the highly conductive thin metal sheet W3, and the highly conductive metal The top surface of the ring-shaped projection P2 of the second highly conductive workpiece W1 is brought into contact with the lower surface of the copper foil w positioned at the lowest position of the thin plate W3. In this state, a pressurizing mechanism is applied between the welding electrodes 1 and 2 by a pressurizing mechanism (not shown). Usually, when a predetermined value is passed in a process in which the pressurizing force increases, a sharply rising joining current is applied to the welding electrode 1. Between the two.

この接合電流が通電するときには、高導電性金属薄板W3の最上位に位置する銅箔wの上面と第1の高導電性被溶接物W1のリング状のプロジェクションP1の頂面との間には前記加圧力が印加されると共に、高導電性金属薄板W3の最下位に位置する銅箔wの下面と第2の高導電性被溶接物W1のリング状のプロジェクションP2の頂面との間には前記加圧力が印加されている。このときリング状のプロジェクションP1とP2とを最短距離で結ぶそれぞれ銅箔w間にもほぼ所定の前記加圧力が加えられるので、リング状のプロジェクションP1、P2を流れる接合電流の多くはリング状のプロジェクションP1とP2とを最短距離で結ぶそれぞれの銅箔wの部分に集中して流れる。したがって、リング状のプロジェクションP1とP2の頂面は、通電前の加圧力をかけているときに圧潰せず、かつ所望の接合強度が得られる最低限の電流密度の接合電流を流すことのできる幅の狭い円環状であることが望ましい。   When this joining current is applied, there is a gap between the upper surface of the copper foil w located at the top of the highly conductive thin metal sheet W3 and the top surface of the ring-shaped projection P1 of the first highly conductive workpiece W1. While the pressing force is applied, between the lower surface of the copper foil w positioned at the lowest position of the highly conductive thin metal sheet W3 and the top surface of the ring-shaped projection P2 of the second highly conductive workpiece W1. The pressure is applied. At this time, almost the predetermined pressure is also applied between the copper foils w that connect the ring-shaped projections P1 and P2 with the shortest distance, so that most of the junction current flowing through the ring-shaped projections P1 and P2 is almost ring-shaped. It flows concentrated on each copper foil w portion connecting the projections P1 and P2 with the shortest distance. Accordingly, the top surfaces of the ring-shaped projections P1 and P2 are not crushed when a pressure is applied before energization, and a junction current having a minimum current density that can obtain a desired junction strength can be passed. A narrow annular shape is desirable.

前述したように、リング状のプロジェクションP1、P2を流れる接合電流の多くがリング状のプロジェクションP1とP2とを最短距離で結ぶそれぞれの銅箔wの部分に集中して流れるとき、第1の高導電性被溶接物W1のリング状のプロジェクションP1の頂面と最上位に位置する銅箔wの上面との間の接触抵抗など、隣り合う銅箔w同士の当接面にそれぞれの接触抵抗など、及び最下位に位置する銅箔wの下面と第2の高導電性被溶接物W1のリング状のプロジェクションP2の頂面との接触抵抗などによって発熱する。そしてこれら各部分の発熱によって、拡散接合が行われる現象については前記実施形態と同様であるので詳しく説明しないが、高導電性金属薄板W3が複数枚銅箔wを重ねたものからなるときには、拡散接合時の発熱によって、図5において破線で示すように、リング状のプロジェクションP1とP2とを最短距離で結ぶそれぞれの銅箔wの部分に近い箇所で盛り上がり、この盛り上がりが接合強度に悪影響を与え、接合強度を低下させることを本発明者はつきとめた。   As described above, when most of the junction current flowing through the ring-shaped projections P1 and P2 flows in a concentrated manner in the portions of the copper foils w that connect the ring-shaped projections P1 and P2 with the shortest distance, the first high current flows. Contact resistance between the top surface of the ring-shaped projection P1 of the conductive workpiece W1 and the upper surface of the uppermost copper foil w, such as contact resistance between the contact surfaces of adjacent copper foils w Further, heat is generated by contact resistance between the lower surface of the copper foil w located at the lowest position and the top surface of the ring-shaped projection P2 of the second highly conductive work piece W1. The phenomenon in which diffusion bonding is performed due to the heat generated by these portions is the same as in the above embodiment and will not be described in detail. However, when the highly conductive thin metal sheet W3 is formed by stacking a plurality of copper foils w, diffusion is performed. As shown by the broken line in FIG. 5, the heat generated during the joining swells at a location close to each copper foil w portion that connects the ring-shaped projections P1 and P2 with the shortest distance, and this swell adversely affects the joining strength. The present inventors have found that the bonding strength is lowered.

この点について詳述すると共に、その対策として銅箔wに設けた凹所V1〜V4について説明する。この拡散接合は、第1の高導電性被溶接物W1のリング状のプロジェクションP1の塑性流動化とプロジェクションP1に当接する最上位に位置する銅箔wの部分の塑性流動化、リング状のプロジェクションP1とP2とを最短距離で結ぶそれぞれの銅箔wの部分の塑性流動化、及び第2の高導電性被溶接物W2のリング状のプロジェクションP2の塑性流動化とプロジェクションP2に当接する最下位に位置する銅箔wの部分の塑性流動化によって行われる。塑性流動化した接合部分は上下からの加圧力によって、銅箔wの幅方向(図5の左右方向)に拡がろうとする。この拡がろうとする左右方向の力によって接合部分近傍の塑性流動化していない部分が変形して盛り上がる。そして、接合部分近傍の塑性流動化していない部分が変形して盛り上がった分だけ接合部分の銅箔wが沈み込むことになる。   This point will be described in detail, and the recesses V1 to V4 provided in the copper foil w will be described as countermeasures. This diffusion bonding is performed by plastic fluidization of the ring-shaped projection P1 of the first highly conductive work piece W1, plastic fluidization of the portion of the copper foil w positioned on the uppermost surface in contact with the projection P1, and ring-shaped projection. Plastic fluidization of each copper foil w portion connecting P1 and P2 with the shortest distance, and plastic fluidization of the ring-shaped projection P2 of the second highly conductive work piece W2 and the lowest level in contact with the projection P2 It is performed by plastic fluidization of the portion of the copper foil w located at. The plastic fluidized joint portion tends to spread in the width direction of the copper foil w (the left-right direction in FIG. 5) by the applied pressure from above and below. Due to the lateral force to expand, the portion that is not plastic fluidized near the joint portion is deformed and raised. And the copper foil w of a joining part sinks by the part which the part which is not plastic-fluidized in the vicinity of a joining part deform | transforms and swells.

特に、リング状のプロジェクションP1とP2に囲まれた銅箔wの部分では、リング状のプロジェクションP1とP2にかけられている加圧力によって、塑性流動化した銅箔wの接合部分は放射内方向に伸びるので、リング状のプロジェクションP1とP2に囲まれた塑性流動化しない部分は盛り上がる。リング状のプロジェクションP1とP2の径が小さいときには、リング状のプロジェクションP1とP2に囲まれた塑性流動化しない部分は小さな紡錘状に盛り上がる。曲がり易い薄い肉厚の銅箔wは接合前のプロジェクションの高さ程度又はそれよりも盛り上がる場合もあり、放射外方向に比べて高く盛り上がる傾向がある。この小紡錘状の盛り上がりは、重ねられた銅箔wのうち、内側に位置する銅箔wよりも外側に位置する銅箔wほど盛り上がりが大きくなることが確認されているが、図5の破線で示すように、積み重ねられた銅箔wの内、中ほどから上側に位置する銅箔wは上側に盛り上がり、中ほどから下側に位置する銅箔wは下側に盛り上がる。図5に示すリング状のプロジェクションP1とP2は拡散接合前のものであり、重ねられた銅箔wの前記盛り上がりが生じなければ、接合電流の通電によってリング状のプロジェクションP1とP2が塑性流動化するのに伴い、加圧力によってリング状のプロジェクションP1とP2は横方向に拡がって当然に低くなり、拡散接合の完了時にはほとんど平面近くまで低くなる。   In particular, in the portion of the copper foil w surrounded by the ring-shaped projections P1 and P2, due to the pressure applied to the ring-shaped projections P1 and P2, the joined portion of the plastic fluidized copper foil w is directed radially inward. Since it stretches, the portion that is surrounded by the ring-shaped projections P1 and P2 and is not plastically fluidized rises. When the diameters of the ring-shaped projections P1 and P2 are small, the portion that is surrounded by the ring-shaped projections P1 and P2 and is not plastically fluidized rises like a small spindle. The thin-walled copper foil w that is easily bent may swell higher than the height of the projection before joining or in some cases, and tends to swell higher than the radial direction. The small spindle-shaped bulge has been confirmed to be larger in the copper foil w positioned on the outer side than the copper foil w positioned on the inner side in the stacked copper foils w. As shown in the figure, among the stacked copper foils w, the copper foil w located from the middle to the upper side rises upward, and the copper foil w located from the middle to the lower side rises downward. The ring-shaped projections P1 and P2 shown in FIG. 5 are those before diffusion bonding, and the ring-shaped projections P1 and P2 are plastically fluidized by energization of the bonding current if the swell of the stacked copper foil w does not occur. As a result, the ring-shaped projections P1 and P2 expand in the lateral direction due to the applied pressure and naturally become low, and are almost lowered to the plane when diffusion bonding is completed.

しかし、図5の破線で示すように、拡散接合が進むにつれて上側に位置する銅箔wが上側に盛り上がると共に、下側に位置する銅箔wが下側に盛り上がり、また、接合部分が沈み込むと、前記盛り上がりが邪魔をして拡散接合の途中から塑性流動化を始めたリング状のプロジェクションP1とP2にかかる加圧力が不十分になり、所望の接合強度を得ることができない。したがって、第1の高導電性被溶接物W1のリング状のプロジェクションP1に囲まれた内側に形成れている凹所V1は、最上位に位置する銅箔wにおけるリング状のプロジェクションP1に囲まれた部分の紡錘状の小さな盛り上がりの高さ程度の深さを有する。その深さは銅箔wの肉厚と積み重ねる枚数、及びリング状のプロジェクションP1の直径などによって異なる。従来の抵抗溶接や拡散接合にあっても、リング状のプロジェクションP1とP2の溶融又は塑性流動化した金属を収容する溝などを設ける場合があったが、実施形態6の凹所V1は従来の溝に比べて容積(容量)が大きい。なお、リング状のプロジェクションP1とP2の径が大きいときには、銅箔wにおけるリング状のプロジェクションP1とP2の内周に沿った部分がリング状に盛り上がることが確認されている。このリング状の盛り上がりも同様に接合強度を低下させる一因となる。したがって、この場合には凹所V1は銅箔wにおけるリング状のプロジェクションP1とP2の内周に沿って形成されたリング状の凹所でよい。   However, as shown by the broken line in FIG. 5, the copper foil w located on the upper side rises upward as the diffusion bonding proceeds, and the copper foil w located on the lower side rises downward, and the joining portion sinks. Then, the above-described swell obstructs the pressure applied to the ring-shaped projections P1 and P2, which started plastic fluidization in the middle of diffusion bonding, and the desired bonding strength cannot be obtained. Therefore, the recess V1 formed inside the ring-shaped projection P1 of the first highly conductive workpiece W1 is surrounded by the ring-shaped projection P1 in the copper foil w located at the uppermost position. It has a depth that is about the height of a small ridge of the spindle-shaped portion. The depth differs depending on the thickness of the copper foil w, the number of stacked copper foils, the diameter of the ring-shaped projection P1, and the like. Even in the conventional resistance welding or diffusion bonding, there is a case where a groove or the like for accommodating the molten or plastic fluidized metal of the ring-shaped projections P1 and P2 is provided. The volume (capacity) is larger than the groove. It has been confirmed that when the diameters of the ring-shaped projections P1 and P2 are large, portions of the copper foil w along the inner periphery of the ring-shaped projections P1 and P2 are raised in a ring shape. This ring-like swell also contributes to a decrease in bonding strength. Therefore, in this case, the recess V1 may be a ring-shaped recess formed along the inner periphery of the ring-shaped projections P1 and P2 in the copper foil w.

凹所V2は第1の高導電性被溶接物W1のリング状のプロジェクションP1の外側周囲に沿って形成されたリング状の凹所であり、最上位に位置する銅箔wにおけるリング状のプロジェクションP1の外側近傍部分の盛り上がりの高さ程度の深さを有する。リング状のプロジェクションP1の外側近傍部分の盛り上がりの高さは、塑性流動化した拡散接合部が放射外方向に伸びるときに、その拡散接合部以外は塑性流動化しなので当然に伸びることは無く、したがって、塑性流動化した拡散接合部が放射外方向に伸びる力によって接合部分の周辺、つまりリング状のプロジェクションP1の外側近傍部分が盛り上がる。この盛り上がりも、接合強度に悪影響を及ぼすほどの盛り上がりを生じる場合が多い。この場合には、凹所V1ほど深くなくても良いが、やはりその盛り上がりを受け入れることができる凹所V2を備えている方が望ましい。第2の高導電性被溶接物W2におけるリング状のプロジェクションP2に囲まれた部分に形成れた凹所V3は凹所V1と同様であるので説明を省略する。第2の高導電性被溶接物W2のリング状におけるプロジェクションP2の外側周囲に沿って形成されたリング状の凹所V4は凹所V2と同様でよいので説明を省略する。   The recess V2 is a ring-shaped recess formed along the outer periphery of the ring-shaped projection P1 of the first highly conductive work piece W1, and the ring-shaped projection in the copper foil w located at the uppermost position. It has a depth that is about the height of the rise in the vicinity of the outside of P1. The height of the bulge in the vicinity of the outer side of the ring-shaped projection P1 is such that when the plastic fluidized diffusion joint extends in the radial outward direction, the parts other than the diffusion joint are plastic fluidized so that they do not naturally extend. The periphery of the joint, that is, the outer vicinity of the ring-shaped projection P1 is raised by the force of the plastic fluidized diffusion joint extending in the radial outward direction. In many cases, this swell also swells so as to adversely affect the bonding strength. In this case, it does not have to be as deep as the recess V1, but it is desirable to provide the recess V2 that can accept the rise. Since the recess V3 formed in the portion surrounded by the ring-shaped projection P2 in the second highly conductive work piece W2 is the same as the recess V1, description thereof will be omitted. The ring-shaped recess V4 formed along the outer periphery of the projection P2 in the ring shape of the second highly conductive work piece W2 may be the same as the recess V2, and the description thereof will be omitted.

この実施形態6では、拡散接合時に塑性流動化したリング状のプロジェクションP1、P2の金属材料も、加圧力によって銅箔wの前記盛り上がりと一緒に凹所V1〜V4に収容されるので、拡散接合面はリング状のプロジェクションP1、P2の根元面域、つまり第1の高導電性被溶接物W1の下側平面、第2の高導電性被溶接物W2の上側平面にほぼあるので、拡散接合面積は凹所V1〜V4が存在しない場合に比べて大きな接合面積なり、接合強度をより向上させることができる。したがって、実施形態6では拡散接合工程の最終段階においても、銅箔wの変形による盛り上がりが凹所V1〜V4に収容されるので、その盛り上がりに邪魔されること無く所定の加圧力が拡散接合工程の最終まで塑性流動化したプロジェクションP1、P2部分と積み重ねられた銅箔wの拡散接合部とに印加されるので、接合強度が低下することも無い。なお、当然のことであるが、凹所V1〜V4部分においては接合強度に寄与していない。   In the sixth embodiment, the metal materials of the ring-shaped projections P1 and P2 plastically fluidized at the time of diffusion bonding are also accommodated in the recesses V1 to V4 together with the bulge of the copper foil w by the applied pressure. Since the surface is substantially in the root plane area of the ring-shaped projections P1, P2, that is, the lower plane of the first highly conductive workpiece W1 and the upper plane of the second highly conductive workpiece W2, diffusion bonding The area is larger than that in the case where the recesses V1 to V4 are not present, and the bonding strength can be further improved. Therefore, in the sixth embodiment, even in the final stage of the diffusion bonding process, the bulge due to the deformation of the copper foil w is accommodated in the recesses V1 to V4, so that a predetermined pressure is applied without being disturbed by the bulge. Since it is applied to the projections P1 and P2 portions plastically fluidized until the end of and the diffusion bonding portion of the copper foil w stacked, the bonding strength is not lowered. As a matter of course, the recesses V1 to V4 do not contribute to the bonding strength.

実施形態6における以上の説明では、プロジェクションP1、P2をリングプロジェクションとして説明したが、プロジェクションP1、P2が一点状又は多点状のものであってもプロジェクションP1、P2の近傍の周囲の銅箔wが前述の理由から円環状に盛り上がることがあるので、その盛り上がりを受け入れる円環状の凹所を第1、第2の高導電性被溶接物W1、W2におけるプロジェクションP1、P2の近傍の周囲に沿って設けるのが望ましい。また、曲がり易い厚みの金属箔に比べて肉厚の厚い高導電性金属薄板W3を1枚又は数枚挟んで拡散接合する場合にも、プロジェクションP1、P2がリングプロジェクションであって、接合電流が10ミリ秒程度以下でピーク値近傍まで急峻に立上る電流の場合には、リングプロジェクションに囲まれた内側部分の高導電性金属薄板W3が急激に変形して盛り上がる場合があるので、やはり前記凹所V1、V3に相当する凹所を第1、第2の高導電性被溶接物W1、W2に備えるのが望ましい。   In the above description of the sixth embodiment, the projections P1 and P2 are described as ring projections. However, even if the projections P1 and P2 are one-point or multi-point, the surrounding copper foil w in the vicinity of the projections P1 and P2 May swell in an annular shape for the above-described reason, and the annular recess for receiving the swell is formed around the vicinity of the projections P1 and P2 in the first and second highly conductive workpieces W1 and W2. It is desirable to provide them. Also, when diffusion bonding is performed by sandwiching one or several high-conductivity thin metal plates W3 that are thicker than a metal foil that is easy to bend, the projections P1 and P2 are ring projections, and the junction current is In the case of a current that rises steeply to the vicinity of the peak value in about 10 milliseconds or less, the highly conductive metal thin plate W3 in the inner part surrounded by the ring projection may be suddenly deformed and raised, so that the concave It is desirable that the first and second highly conductive workpieces W1 and W2 are provided with recesses corresponding to the locations V1 and V3.

このように、プロジェクションP1、P2がリングプロジェクションの場合にはそれらの内側、外側の双方に凹所を備えるのが好ましいが、図7(A)に示すようにリング状のプロジェクションP1、P2の内側だけに凹所V1、V3をそれぞれ備えるか、あるいは図7(B)に示すようにリング状のプロジェクションP1、P2の外側だけに凹所V2、V4をそれぞれ備えるだけでもよい。なお、以上の実施形態ではいずれも拡散接合面にスズ膜のような低融点金属膜を形成しなかったが、所望の接合強度を得やすいといった面からは、プロジェクションP1、P2の先端面及びそれらプロジェクションP1、P2に当接する高導電性金属薄板W3の面域のいずれか一方又は双方に低融点金属膜をあらかじめ形成しておいても構わない。   As described above, when the projections P1 and P2 are ring projections, it is preferable to provide recesses on both the inside and the outside, but as shown in FIG. 7A, the insides of the ring-shaped projections P1 and P2 are provided. Only the recesses V1 and V4 may be provided, or the recesses V2 and V4 may be provided only outside the ring-shaped projections P1 and P2 as shown in FIG. In each of the above embodiments, a low melting point metal film such as a tin film was not formed on the diffusion bonding surface. From the viewpoint of easily obtaining a desired bonding strength, the front end surfaces of the projections P1 and P2 and those A low melting point metal film may be formed in advance on one or both of the surface areas of the highly conductive thin metal sheet W3 that contacts the projections P1 and P2.

[プロジェクション溶接装置の好ましい一例]
次に、プロジェクションPが形成された銅部材などの高導電性被溶接物である第1の被溶接物W1と銅部材などの高導電性被溶接物である第2の被溶接物W2とのプロジェクション溶接(拡散接合)を実現するのに好適なコンデンサ式の抵抗溶接装置の一例を図5によって簡潔に説明する。図8において、図1〜図7で用いた記号と同一の記号は同じ名称の部材を示すものとする。床などに固定されている支持機構3には、シリンダ装置などからなる加圧機構4が取り付けられ、加圧機構4の先端部には可動ブロック5が取り付けられている。スプリング又は電磁加圧装置のような加圧補助部材6が可動ブロック5と支持部材7との間に備えられ、溶接電極1の加圧応答を向上させる補助的な役割を行っている。
[Preferred example of projection welding apparatus]
Next, a first workpiece W1 that is a highly conductive workpiece such as a copper member on which the projection P is formed and a second workpiece W2 that is a highly conductive workpiece such as a copper member. An example of a capacitor-type resistance welding apparatus suitable for realizing projection welding (diffusion bonding) will be briefly described with reference to FIG. In FIG. 8, the same symbols as those used in FIGS. 1 to 7 indicate members having the same names. A pressurizing mechanism 4 composed of a cylinder device or the like is attached to the support mechanism 3 fixed to the floor or the like, and a movable block 5 is attached to the tip of the pressurizing mechanism 4. A pressure auxiliary member 6 such as a spring or an electromagnetic pressure device is provided between the movable block 5 and the support member 7, and plays an auxiliary role to improve the pressure response of the welding electrode 1.

高導電性部材同士、特に銅部材又はアルミニウム部材の抵抗溶接ではこの加圧補助部材6の働きは大きい。ここで、支持部材7は直接又は間接的に加圧補助部材6の下端部に結合され、給電部としても作用する銅のような導電性の良好な金属材料からなる。上部側の溶接電極1は支持部材7に支承されており、溶接電極1と向かい合った位置には下部側の溶接電極2が配置されている。加圧補助部材6の伸縮の影響を受けない高さに位置する可動ブロック5にはL字形の中間接続部材8が固定されている。支持部材7とL字形中間接続部材8との間を接続する撓み易い第1のフレキシブル導電部材9が備えられ、L字形の中間接続部材8と一方の給電導体10との間は第2のフレキシブル導電部材11によって接続されている。溶接電極1と溶接電極2とは、例えば銅合金からなる。   In the resistance welding of highly conductive members, particularly a copper member or an aluminum member, the function of the pressure auxiliary member 6 is great. Here, the support member 7 is directly or indirectly coupled to the lower end portion of the pressure assisting member 6 and is made of a metal material having good conductivity such as copper that also functions as a power feeding portion. The upper side welding electrode 1 is supported by a support member 7, and the lower side welding electrode 2 is arranged at a position facing the welding electrode 1. An L-shaped intermediate connecting member 8 is fixed to the movable block 5 located at a height that is not affected by the expansion and contraction of the pressure assisting member 6. A flexible first flexible conductive member 9 that connects between the support member 7 and the L-shaped intermediate connection member 8 is provided, and a second flexible conductor is provided between the L-shaped intermediate connection member 8 and one power supply conductor 10. They are connected by a conductive member 11. The welding electrode 1 and the welding electrode 2 are made of, for example, a copper alloy.

給電導体10と、溶接電極2に接続された他方の給電導体12との間に溶接トランス13の2次巻線N2が接続され、これに磁気的に結合された1次巻線N1にはインバータ回路又は半導体スイッチ回路のような放電回路14が接続される。放電回路14にはエネルギー蓄積用コンデンサ15とそのコンデンサを充電する充電回路16とが接続されている。抵抗溶接にあっては、溶接に寄与する溶接電流のほとんどは立ち上がりからピーク値近傍までの電流であるので、実施形態5の抵抗溶接では溶接電流がピーク値近傍まで立ち上がる時間が10ms程度以下であり、7ms以下であることが好ましいことについては既に述べたが、このプロジェクション溶接装置はこのようなパルス幅の狭い急峻なパルス状電流が銅部材と銅部材との間に流れることができるような構成になっている。そして、この構造では溶接電極1は僅かな外力で上下方向に上下動できる支持部材7に支えられていると同時に、即応性の高い弾性力を与えることができる加圧補助部材6に結合されているので、第1、第2の被溶接物W1、W2又は高導電性金属薄板W3に形成されたプロジェクションとそれらの当接部分が塑性流動したときに生じる溶接電極1と溶接電極2との間の微妙な加圧力の変化に対して、溶接電極1が即応することができる。なお、記号17〜19は3相交流入力端子を示す。   The secondary winding N2 of the welding transformer 13 is connected between the power supply conductor 10 and the other power supply conductor 12 connected to the welding electrode 2, and the primary winding N1 magnetically coupled thereto is connected to the inverter. A discharge circuit 14 such as a circuit or a semiconductor switch circuit is connected. Connected to the discharge circuit 14 are an energy storage capacitor 15 and a charging circuit 16 for charging the capacitor. In resistance welding, since most of the welding current that contributes to welding is current from the rise to the vicinity of the peak value, in the resistance welding of the fifth embodiment, the time for the welding current to rise to the vicinity of the peak value is about 10 ms or less. As described above, it is preferable that the length is 7 ms or less. However, the projection welding apparatus has a configuration in which such a steep pulse current with a narrow pulse width can flow between the copper members. It has become. In this structure, the welding electrode 1 is supported by a support member 7 that can be moved up and down with a slight external force, and at the same time, is coupled to a pressurizing auxiliary member 6 that can provide a highly responsive elastic force. Therefore, the projections formed on the first and second workpieces W1 and W2 or the highly conductive thin metal plate W3 and the welding electrode 1 and the welding electrode 2 generated when the contact portions thereof are plastically flowed are provided. The welding electrode 1 can immediately respond to the slight change in pressure. Symbols 17 to 19 indicate three-phase AC input terminals.

次に、このプロジェクション溶接装置の動作について簡単に説明する。例えば、図1に示したように溶接電極1と2との間に第1、第2の被溶接物W1、W2及び高導電性金属薄板W3が配置されると、加圧機構4が下方向に動作し、これに伴い、可動ブロック5、加圧補助部材6、支持部材7及び溶接電極1からなる上部溶接ヘッド全体が下降し、溶接電極1が第1、第2の被溶接物W1、W2及び高導電性金属薄板W3に所定の加圧力を加える。この所定の加圧力を加えている途中、あるいは加圧力がほぼ一定になった段階で、放電回路14がオンして、充電回路16により既にエネルギー蓄積用コンデンサ15に充電されている電荷を、溶接トランス13の1次巻線N1に放出する。これに伴い、1次巻線N1に比べて巻数が大幅に少ない1ターン又2ターン程度の2次巻線N2に大きな電流が発生し、溶接電極1と溶接電極2とその間に挟まれている第1、第2の被溶接物W1、W2及び高導電性金属薄板W3を介して急峻で大きなパルス状溶接電流が流れる。   Next, the operation of the projection welding apparatus will be briefly described. For example, when the first and second workpieces W1 and W2 and the highly conductive thin metal plate W3 are disposed between the welding electrodes 1 and 2 as shown in FIG. Accordingly, the entire upper welding head composed of the movable block 5, the pressure assisting member 6, the support member 7 and the welding electrode 1 is lowered, and the welding electrode 1 is moved to the first and second workpieces W1, A predetermined pressing force is applied to W2 and the highly conductive thin metal plate W3. During the application of the predetermined pressure, or when the pressure becomes substantially constant, the discharge circuit 14 is turned on, and the charge already charged in the energy storage capacitor 15 by the charging circuit 16 is welded. It is discharged to the primary winding N1 of the transformer 13. Along with this, a large current is generated in the secondary winding N2 having one or two turns which is significantly smaller than the primary winding N1, and is sandwiched between the welding electrode 1 and the welding electrode 2. A steep and large pulse welding current flows through the first and second workpieces W1 and W2 and the highly conductive thin metal plate W3.

溶接時に印加される前記加圧力によって第1の被溶接物W1のプロジェクションP1と第2の被溶接物W2のプロジェクションP2は変形しても圧潰することはないから、前述のようなパルス状溶接電流は、前述したように第1の被溶接物W1のプロジェクションP1と高導電性金属薄板W3との当接部、及び第2の被溶接物W2のプロジェクションP2と高導電性金属薄板W3との当接部に集中して短時間流れ、それら当接部が塑性流動化する。この塑性流動の過程で、加圧補助部材6は加圧機構4の下方向の加圧力を常に弾性的に受けているので、第1の被溶接物W1のプロジェクションP1と高導電性金属薄板Wとの当接部、及び第2の被溶接物W2のプロジェクションP2と高導電性金属薄板Wとの当接部が塑性流動化する過程で、それら当接部が軟化するのに伴い常に当接部の塑性流動化した銅材料を互いに押し込む。   Since the projection P1 of the first workpiece W1 and the projection P2 of the second workpiece W2 are not crushed even if they are deformed by the pressure applied during welding, the pulse welding current as described above is used. As described above, the contact portion between the projection P1 of the first workpiece W1 and the highly conductive metal thin plate W3, and the contact between the projection P2 of the second workpiece W2 and the high conductive metal thin plate W3. It flows for a short time while concentrating on the contact portion, and the contact portion is plastically fluidized. In the process of plastic flow, the pressure assisting member 6 always elastically receives the downward pressing force of the pressure mechanism 4, so that the projection P1 of the first workpiece W1 and the highly conductive thin metal plate W are applied. In the process of plastic fluidization of the abutting portion of the second workpiece W2 and the abutting portion of the projection P2 of the second work piece W2 and the highly conductive thin metal plate W, the abutting portion always abuts as the abutment portion softens. The plastic fluidized copper materials of the parts are pushed together.

ここでは、スプリング又は電磁加圧装置のような加圧補助部材6による弾力性のある加圧力を弾性的加圧力という。つまり、この溶接装置ではその弾性的加圧力を加圧機構4による加圧力に重畳してなる加圧力を溶接電極間に加え、即応できる機構を備えることによって、第1の被溶接物W1と第2の被溶接物W2と高導電性金属薄板W3との塑性流動による沈み込みに対しても極めて応答の速い加圧を与えることができ、この加圧補助部材6の弾性的加圧力によって溶接電極1の応答速度が速ければ速いほど、パルス幅の短いパルス状溶接電流を、つまり短時間に電流エネルギーを集中して第1の被溶接物W1と第2の被溶接物W2と高導電性金属薄板W3との間に流すことがでる。したがって、銅部材又はアルミニウム部材のような熱伝導の極めて良好な高導電性金属材料でも、好ましい状態に塑性流動化させることができ、このことが高導電性金属材料でも簡単に満足のいくプロジェクション溶接を行える一つの大きな要因になっている。   Here, the elastic pressure applied by the pressure auxiliary member 6 such as a spring or an electromagnetic pressure device is called an elastic pressure. That is, in this welding apparatus, the first welding object W1 and the first welding object W1 are provided by providing a mechanism capable of applying a pressing force obtained by superimposing the elastic pressing force on the pressing force by the pressing mechanism 4 between the welding electrodes. 2 can be applied with a very quick response to the subsidence caused by plastic flow between the work piece 2 and the highly conductive metal thin plate W3. The faster the response speed of 1, the shorter the pulse width of the pulse welding current, that is, the current energy is concentrated in a short time, and the first work piece W1, the second work piece W2, and the highly conductive metal. It can flow between the thin plates W3. Therefore, even a highly conductive metal material with extremely good thermal conductivity, such as a copper member or an aluminum member, can be plastically fluidized to a desirable state, which is a projection welding that can be easily satisfied even with a highly conductive metal material. It is one big factor that can do.

なお、図8に示したプロジェクション溶接装置では、図1を用いて説明した実施形態1の溶接方法を行った例について述べたが、図2〜図7を用いて説明した実施形態2〜実施形態6に係るプロジェクション溶接も、溶接電極など一部分を変更することによって同様に行うことができる。図8に示した抵抗溶接装置は一例であって、短時間で大電流のパルス状電流を通電でき、被溶接物の塑性流動化に伴う溶接電極間の圧力変化に即応できる、つまり弾性的加圧力を加えることができるものであるならば、他の構成のものであっても勿論よい。また、上記実施形態3〜5において、プロジェクションP1、P2は、1点又は多点のプロジェクション、あるいは、一般的な形状のリングプロジェクションであってもよく、プロジェクションの形状には制限されない。   In addition, although the example which performed the welding method of Embodiment 1 demonstrated using FIG. 1 was described in the projection welding apparatus shown in FIG. 8, Embodiment 2-Embodiment demonstrated using FIGS. The projection welding according to 6 can be similarly performed by changing a part of the welding electrode or the like. The resistance welding apparatus shown in FIG. 8 is an example, and can apply a high-current pulsed current in a short time, and can immediately respond to the pressure change between the welding electrodes accompanying plastic fluidization of the work piece, that is, elastically applied. Of course, other configurations may be used as long as pressure can be applied. In the third to fifth embodiments, the projections P1 and P2 may be one-point or multi-point projections or ring projections having a general shape, and are not limited to the shape of the projection.

本発明の実施形態1に係るプロジェクション溶接方法を説明するための図である。It is a figure for demonstrating the projection welding method which concerns on Embodiment 1 of this invention. 本発明の実施形態2、実施形態3に係るプロジェクション溶接方法を説明するための図である。It is a figure for demonstrating the projection welding method which concerns on Embodiment 2 and Embodiment 3 of this invention. 本発明の実施形態4に係るプロジェクション溶接方法を説明するための図である。It is a figure for demonstrating the projection welding method which concerns on Embodiment 4 of this invention. 本発明の実施形態5に係るプロジェクション溶接方法を説明するための図である。It is a figure for demonstrating the projection welding method which concerns on Embodiment 5 of this invention. 本発明の実施形態6に係るプロジェクション溶接方法に用いられる被溶接物の一例を説明するための図である。It is a figure for demonstrating an example of the to-be-welded object used for the projection welding method which concerns on Embodiment 6 of this invention. 本発明の実施形態6に係るプロジェクション溶接方法を説明するための図である。It is a figure for demonstrating the projection welding method which concerns on Embodiment 6 of this invention. 本発明の実施形態6に係るプロジェクション溶接方法で溶接される被溶接物の一例を示している。The example of the to-be-welded object welded with the projection welding method which concerns on Embodiment 6 of this invention is shown. 本発明のプロジェクション溶接方法を実現するためのプロジェクション溶接装置の好ましい一例を示す図である。It is a figure which shows a preferable example of the projection welding apparatus for implement | achieving the projection welding method of this invention.

W1・・・第1の被溶接物(高導電性被溶接物)
W2・・・第2の被溶接物(高導電性被溶接物)
W3・・・高導電性金属薄板
P1〜P4・・・プロジェクション
V1〜V4・・・凹所
1、2・・・溶接電極
3・・・支持機構
4・・・加圧機構
5・・・可動ブロック
6・・・加圧補助部材
7・・・支持部材
8・・・L字形の中間接続部材
9・・・第1のフレキシブル導電部材
10・・・給電導体
11・・・第2のフレキシブル導電部材
12・・・給電導体
13・・・溶接トランス
14・・・放電回路
15・・・エネルギー蓄積用コンデンサ
16・・・充電回路
17〜19・・・3相交流入力端子
W1 ... first workpiece (highly conductive workpiece)
W2 ... second workpiece (highly conductive workpiece)
W3: Highly conductive thin metal plate P1-P4 ... Projection V1-V4 ... Recess 1, 2 ... Welding electrode 3 ... Support mechanism 4 ... Pressure mechanism 5 ... Movable Block 6 ... Pressure assisting member 7 ... Support member 8 ... L-shaped intermediate connection member 9 ... First flexible conductive member 10 ... Feeding conductor 11 ... Second flexible conductive member Member 12 ... Feeding conductor 13 ... Welding transformer 14 ... Discharge circuit 15 ... Energy storage capacitor 16 ... Charging circuit 17-19 ... Three-phase AC input terminal

Claims (2)

第1の高導電性被溶接物と第2の高導電性被溶接物との間に溶接電流を流して抵抗溶接を行う高導電性被溶接物のプロジェクション溶接方法であって、
前記第1の高導電性被溶接物及び前記第2の高導電性被溶接物はそれぞれプロジェクションを有し、
前記第1の高導電性被溶接物と前記第2の高導電性被溶接物とを前記プロジェクションが対向するように向かい合わせ、前記プロジェクション同士の間に、前記第1の高導電性被溶接物又は前記第2の高導電性被溶接物の金属材料と同一の金属材料からなる高導電性金属薄板を介在させ、
前記第1の高導電性被溶接物と前記第2の高導電性被溶接物との間に、弾性的加圧力を加えた状態でパルス状溶接電流を通電することを特徴とする高導電性被溶接物のプロジェクション溶接方法において、
前記高導電性金属薄板は高導電性金属箔を複数枚重ねたものからなり、
前記第1の高導電性被溶接物及び前記第2の高導電性被溶接物は、それぞれの前記プロジェクションの周囲に、拡散接合時に生じる前記高導電性金属箔の盛り上がりを受け入れる凹所を備えることを特徴とする高導電性被溶接物のプロジェクション溶接方法。
A projection welding method for a highly conductive workpiece that performs resistance welding by passing a welding current between a first highly conductive workpiece and a second highly conductive workpiece,
Each of the first highly conductive workpiece and the second highly conductive workpiece has a projection,
The first highly conductive work piece and the second high conductive work piece are faced so that the projections face each other, and the first high conductive work piece is interposed between the projections. Or interposing a highly conductive metal thin plate made of the same metal material as the metal material of the second highly conductive work piece,
Highly conductive, characterized in that a pulsed welding current is passed between the first highly conductive workpiece and the second highly conductive workpiece with an elastic pressure applied. In the projection welding method of the workpiece,
The highly conductive metal thin plate is composed of a plurality of stacked highly conductive metal foils,
The first highly conductive work piece and the second highly conductive work piece include a recess around each projection for receiving the bulge of the highly conductive metal foil generated during diffusion bonding. A projection welding method for a highly conductive workpiece.
請求項1において、
前記高導電性金属薄板は、前記第1の高導電性被溶接物と前記第2の高導電性被溶接物との間から外部に延びて、第3の高導電性被溶接物として作用することを特徴とする高導電性被溶接物のプロジェクション溶接方法。
In claim 1,
The highly conductive metal thin plate extends from between the first highly conductive workpiece and the second highly conductive workpiece and acts as a third highly conductive workpiece. A projection welding method for a highly conductive workpiece to be welded.
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