JP2011161512A - Electromagnetic welding coil and method for fixing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, regarding a one turn coil subjecting a metal thin sheet to electromagnetic welding into a seam shape, when seam welding is performed with the conventional coil, the seam width is 3 to 5 mm, and welding with the seam width of ≤1 mm has not been performed. <P>SOLUTION: A large current reciprocating between the current concentration part 1a (width 1 mm) in a coil and the peripheral part 1c is rapidly made to flow, and aluminum sheets 2 plated thereon are welded. For the purpose of preventing the deformation of the current concentration part 1a, forces 5 are applied from the circumference using a fixed plate 3 and an insulting material 4. The aluminum plates 2 are welded at a seam welding width of about 1 mm along the current concentration part 1a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electromagnetic welding coil and a fixing method for welding plates and foils of aluminum, copper, and the like, which are used in the field of assembling electric and electronic components such as electrode plates and printed wiring boards, by electromagnetic force.

As a method for easily welding an aluminum plate that is difficult to weld, there are electromagnetic welding methods developed by the present inventors (Patent Documents 1 to 3). This electromagnetic welding method uses a flat plate-shaped one-turn coil provided with a current-concentrating portion or a U-shaped one-turn coil in which a rectangular electric wire is reciprocated in an electromagnetic welding apparatus for welding an aluminum plate or the like with an electromagnetic force. This is a method in which a large discharge current is passed from the power supply to the coil, and an aluminum plate or the like placed on the flat one-turn coil or inside the U-shaped coil is welded in a seam (wire) form by electromagnetic force. .
Japanese Patent No. 3751153 Japanese Patent No. 3852823 Patent No. 3944202

  FIG. 1 is a perspective view (partial cross-sectional view) of a typical flat plate-shaped one-turn coil 1 conventionally used. The material of the coil is copper or a copper alloy through which current easily flows. The current flows into the current concentration portion 1a at the center of the narrow coil, changes direction at the folded portion 1b, and flows out from the wide peripheral portion 1c. The number of coil turns is 1, which is called a one-turn coil. A symbol (× or... In a circle) drawn on the cross section of FIG. 1 is a symbol indicating the direction of current.

  FIG. 2 is a cross-sectional view showing a state in which the aluminum plate 2 is welded using the flat one-turn coil 1 (1a, 1b, 1c). The coil 1 is electrically insulated by a thin polyimide sheet (not shown) or the like, and is pressed and fixed by upper and lower fixing plates 3 together with an aluminum plate 2 placed thereon. The pressurizing device is omitted.

  The plate thickness of the flat one-turn coil 1 and the cross-sectional width of the current concentration portion 1a are preferably as thin and narrow as possible in order to efficiently generate a large electromagnetic force. However, during welding, a large discharge current flows through the current concentration portion 1a, and a large electromagnetic force acts as a reaction also in this portion. For this reason, the coil plate thickness is selected to be 2 to 3 mm, and the cross-sectional width of the current concentration portion 1a is selected to be 3 to 5 mm. In order to prevent the current concentration portion 1a from being deformed by electromagnetic force (reaction), a strong fixing plate 3 is disposed below the flat one-turn coil 1.

  When the cross-sectional width of the current concentration portion 1a is narrowed, the pressure of the electromagnetic force (reaction) increases, the lower fixing plate 3 is dented, and the current concentration portion 1a is easily deformed. Usually, the cross-sectional width of the current concentration portion 1a is made larger than the plate thickness, and the pressure of the electromagnetic force generated in the current concentration portion 1a is reduced (dispersed) to prevent deformation of this portion. This type of coil in which the cross-sectional width of the current concentration portion 1a is smaller than the plate thickness is not found.

  In the U-shaped one-turn coil obtained by reciprocating the flat electric wire, the flat electric wire corresponds to the current concentration portion 1a in FIG. Although the structure of the coil is different, the horizontal width and vertical width of the cross section in the direction perpendicular to the current of the rectangular electric wire are 2 to 5 mm, respectively, and the cross-sectional horizontal width and vertical width (plate thickness) of the current concentrated portion 1a of the flat plate-shaped one-turn coil 1 Almost equal. For this reason, the problem of the cross-sectional shape which arises in the case of a flat plate-shaped one-turn coil, the solution means, etc. can be considered substantially the same in the case of a U-shaped one-turn coil.

Generally, a capacitor power source is used as a power source for the electromagnetic welding apparatus. The capacity of the capacitor power source is 10 to 400 μF, and the charging energy is 1 to several kJ. When a discharge current is supplied from the capacitor power source to the flat plate-shaped one-turn coil 1, a large current of 100 kA or more at the maximum value flows in the coil for a short time of 100 μs or less. A high-density magnetic flux is suddenly generated in the current concentration portion 1a (width 3 to 5 mm) of the coil and intersects the aluminum plate (material to be welded) 2. An induced current called an eddy current flows through the aluminum plate 2 and is heated and electromagnetic force is applied. As a result, the aluminum plate 2 is subjected to seam welding (pressure welding) along the current concentration portion 1a (Non-Patent Documents 1 to 3).
“Light Metal” vol. 54, No. 4 (2004) p. 153 “Light Metal Welding”, Vol. 41, No. 3, (2003) p. 114 “Journal of the Japan Welding Society” Vol. 77, No. 8 (2008) 6

In the welding apparatus using the conventional flat one-turn coil 1 shown in FIG. 1, the width of the seam-welded portion is 3 to 5 mm in cross-sectional width of the coil current concentration portion 1a. It is difficult to set the seam weld width to 1 mm or less. The reason is that if the cross-sectional width of the coil current concentration portion 1a is 1 mm or less, deformation or melting is likely to occur when a large discharge current is passed (Non-Patent Document 4).
“Plasticity and processing”, Volume 50, No. 585 (2009) p. 936

  A method is conceivable in which the cross-sectional width of the coil current concentration portion 1a is set to 1 mm or less and the periphery of this portion is fixed with an insulating material to prevent deformation of this portion. However, since the thickness of the flat coil was as thin as 2 to 3 mm, it could not be fixed sufficiently. Moreover, if the side surface of the current concentration portion 1a is fixed with an insulating material, it is difficult to dissipate heat at this portion, and it is easy to melt.

  For these reasons, there has been no idea so far that the cross-sectional width of the coil current concentration portion 1a is 1 mm or less and the seam weld width is 1 mm or less. The seam weld width of 1 mm or less is particularly necessary in the field of assembling printed wiring boards and electronic components that are becoming narrower. Narrowing the seam welding width to perform electromagnetic welding is a problem to be solved. An object of the present invention is to provide an electromagnetic welding coil and a fixing method that can solve this problem and reduce the seam welding width.

  A method for solving the above-described problems will be described in order by setting the cross-sectional width of the current concentrated portion 1a of the flat one-turn coil 1 (FIGS. 1 and 2) to 1 mm or less.

(1) The cross-sectional shape of the current concentration portion 1a is rectangular, the lateral width is 1 mm or less, and the plate thickness of the flat one-turn coil 1 is 10 mm to 20 mm.

(2) In order to prevent deformation of the current concentration portion 1a having a width of 1 mm or less, a strong insulating material having the same thickness as the coil plate thickness is newly provided between the current concentration portion 1a of the coil and the wide peripheral portion 1c. Put in.

(3) The entire coil containing the insulating material is pressurized and fixed from the side of the coil. Since the surface area of the current concentration part is large, it is easy to press and fix and prevent deformation.

(4) Several cooling passages penetrating the inside of the coil including the insulating material are provided in a direction perpendicular to the coil current direction and horizontal. Thereby, even if the current concentration portion 1a is fixed with an insulating material, the current concentration portion is radiated and the current concentration portion is hardly melted.

  Based on the above means, the present invention repeats the experiment, examines the cross-sectional shape of the current concentration portion 1a, applies a large discharge current, and does not deform or melt even if the seam weld width is 1 mm or less. Coil and fixing method were devised.

  When the flat plate-shaped one-turn coil for electromagnetic welding according to the first to third aspects of the present invention is used, plates and foils such as aluminum and copper can be stacked, and this portion can be electromagnetically welded with a seam weld width of 1 mm or less. It can be used as a highly reliable connection method to replace soldering and ultrasonic bonding in the field of assembly of printed wiring boards and electrical / electronic components that are becoming thinner and lighter, especially in automotive circuit parts where the usage environment is severe. . In addition, if a cooling passage that penetrates the inside of the coil is provided, heat radiation at the current concentration portion is facilitated, and continuous welding is possible.

  In addition, even if the U-shaped one-turn coil for electromagnetic welding according to the inventions of claims 4 to 6 is used, electromagnetic welding can be performed with a seam weld width of 1 mm or less as in the case of the flat one-turn coil.

  Embodiments of the present invention will be described below with reference to the accompanying drawings (FIGS. 3 to 12).

  FIG. 3 is a perspective view (partial cross section) showing only the flat plate-shaped one-turn coil 1 for electromagnetic welding according to the present invention. As in FIG. 1, the current flows into the current concentration portion 1a at the center of the narrow coil, changes direction at the folded portion 1b, and flows out from the wide peripheral portion 1c. FIG. 4 is a cross-sectional view perpendicular to the current and shows the arrangement of the insulating material 4 that fixes the current concentration portion 1a of the coil 1.

  The material of the flat one-turn coil 1 shown in FIGS. 3 and 4 is copper or a copper alloy. The plate thickness is about 15 mm. The cross-sectional width of the current concentration portion 1a of this coil is about 1 mm. The material of the insulating material 4 placed on both sides of the current concentration portion 1a is preferably polyacetal or polycarbonate. The width of the insulating material 4 is desirably about 10 mm.

  If the plate-like one-turn coil 1 is too thin, it is difficult to fix the insulating material 4, and if it is too thick, the current density of the flowing current is reduced. When the current density is reduced, the electromagnetic force for welding is not sufficient. For this reason, the plate thickness of the coil 1 is desirably in the range of 10 to 20 mm.

  FIG. 5 is a cross-sectional view (in a direction perpendicular to the current) showing a state in which the aluminum plate (material to be welded) 2 actually stacked using the flat plate-shaped one-turn coil 1 (1a, 1c) is welded. A discharge current having a maximum value of 100 kA or more is passed through the flat coil 1 for a short time. A high-density magnetic flux (not shown) is suddenly generated in the current concentration portion 1 a and intersects the aluminum plate 2. An induced current called an eddy current flows through the plate 2 and is heated and electromagnetic force works. As a result, the aluminum plate 2 is seam welded along the current concentration portion 1a with a seam weld width of about 1 mm.

  A method of fixing the current concentration portion 1a having a width of about 1 mm will be described with reference to FIG. The current concentration portion 1a and the insulating material 4 are tightened from the horizontal direction of FIG. 5 by a mechanical method (for example, a hydraulic cylinder mechanism). In FIG. 5, the tightening force (direction) 5 is indicated by an arrow. Since the area of the current concentration portion 1a to be tightened is wide, deformation of the current concentration portion 1a can be prevented with a normal tightening force.

  An example of welding conditions and experimental results is shown. The capacity of the capacitor power supply is 24 μF, and the charging energy is 1 to 2 kJ. When a discharge current is supplied from the power source to the flat plate-shaped one-turn coil 1 as described above, a large current of about 200 kA maximum flows through the coil for a short time of about 30 μs. The thickness of the aluminum plate (material to be welded) 2 is 0.3 mm, and the size is 50 mm × 50 mm. The overlapping width of the aluminum plate 2 is 5 to 20 mm. At this time, the maximum magnetic flux density generated between the coil 1 and the aluminum plate 2 is approximately 30 T, and the magnetic pressure corresponding to the generated electromagnetic force is approximately 260 MPa at the maximum (Non-patent Document 5).

The aluminum plate 2 was seam welded with a length of about 1 mm over a length of 50 mm. When welding was performed at a charging energy of about 1 kJ or more, a joining strength at which the base metal fractured in the tensile shear test was obtained. This value was about 130 MPa. No deformation was observed in the current concentration portion 1a of the coil. It is expected that the entire coil including the insulating material is pressed and fixed from the coil side surface (Non-Patent Document 5).
"Journal of the Japan Welding Society Annual Meeting", Vol. 86 (2010), scheduled to be published in March, scheduled for April (lecture number 128)

  When it is necessary to dissipate the current concentration portion 1a during repeated welding using the flat plate-shaped one-turn coil 1, the cooling passage 6 penetrating the current concentration portion 1a, the peripheral portion 1c and the insulating material 4 is provided. Provided as shown in FIG. The cross-section of the passage 6 is circular or the like, and its diameter is about 4 mm, and the number of passages is preferably one per 10-15 mm in the length in the direction in which the current of the current concentration portion 1a flows. Cooling air flows through this passage.

  FIG. 7 is a plan view of the flat plate one-turn coil 1 provided with a notch 7 having a width of about 1 mm and a depth of about 10 mm so that the current flows around the folded portion 1b of the flat plate-shaped one-turn coil. The coil current flows around the folded portion 1b (concentrates on a part of the current concentration portion 1a) and prevents a part of the current concentration portion 1a from melting.

  FIG. 8 is a plan view of the flat one-turn coil 1 having a structure in which only the current concentration portion 1a can be separated from other portions of the coil. When welding continuously many times using this coil 1, the surface is damaged with the number of times. In such a case, it is convenient that only the current concentration portion 1a can be replaced. The electrical connection between the current concentration portion 1a and the other portion of the coil is obtained by mechanical tightening from the horizontal direction in FIG.

  FIG. 9 is a perspective view of the U-shaped one-turn coil 8 for electromagnetic welding according to the present invention. The electric current flows back and forth in the flat electric wires 9 arranged in parallel. The short-circuit copper plate 10 is electrically connected to the end of the flat electric wire. FIG. 10 is a cross-sectional view showing a state in which the aluminum plates (materials to be welded) 2 stacked using the coil 8 are welded.

  The material of the U-shaped one-turn coil 8 is copper or a copper alloy. The width (horizontal direction) of the cross section of the two flat electric wires 9 is about 1 mm, and the vertical width (vertical direction in FIG. 10) is about 15 mm. An insulating material 4 such as polyacetal or polycarbonate is placed on both sides of the flat electric wire 9, and the flat electric wire 9 is fixed together with the fixing plate 3. The insulating material 4 has a horizontal width of 50 mm or more and a vertical width (vertical direction) of about 15 mm.

  When heat radiation of the flat electric wire 8 is necessary, a cooling passage is provided in the flat electric wire 8 including the insulating material 4 in a direction perpendicular to the direction in which current flows (see FIG. 6).

  FIG. 11 is a cross-sectional view showing a state in which stacked aluminum plates (materials to be welded) 2 are welded using another U-shaped one-turn coil 8 for electromagnetic welding according to the present invention. Compared with Example 5, only one flat electric wire 9 has the same arrangement and is similarly fixed. The other rectangular electric wire 9 is fixed by the fixing plate 3 with an increased width (horizontal direction). Used when welding two aluminum plates with different materials and thicknesses.

  FIG. 12 is a cross-sectional view showing a state where an aluminum plate (material to be welded) 2 is welded using a one-turn coil composed of three flat electric wires 9a and 9b according to the present invention. The central flat electric wire 9a (rectangular cross section) has a cross-sectional width (horizontal direction) of 1 mm or less, a vertical width of 10 mm to 20 mm, and the remaining flat electric wires 9b on both sides have a cross-sectional width of 30 mm or more and a vertical width of 1 mm to 5 mm. The insulating material 4 is placed on both sides of the central flat electric wire 9a, and is used to fix the three flat electric wires 9a and 9b together with the fixing plate 3.

  Due to the structure, the current flowing through the central flat wire 9a in FIG. For this reason, welding can be performed with higher energy efficiency than the flat plate-like one-turn coil 1 shown in FIGS.

  It is a perspective view (partial cross section) of a conventional typical flat plate-shaped one-turn coil.   It is sectional drawing which shows the state which welds an aluminum plate (to-be-welded material) using the conventional typical flat plate one-turn coil.   It is a perspective view (partial cross section) figure of the flat plate-shaped one-turn coil which shows Example 1 of this invention.   It is sectional drawing of the insulating material which fixes the electric current concentration part of the flat plate-shaped one-turn coil which shows Example 1 of this invention.   It is sectional drawing which shows the state which welds an aluminum plate (to-be-welded material) using the flat plate-shaped one-turn coil of Example 1 of this invention.   It is sectional drawing which shows the channel | path for cooling of Example 2 of this invention.   It is a top view of the flat plate one-turn coil which shows Example 3 of this invention.   It is a top view of the flat plate one-turn coil which shows Example 4 of this invention.   It is a perspective view of the U-shaped one-turn coil which shows Example 5 of this invention.   It is sectional drawing which shows the state which welds an aluminum plate (to-be-welded material) using the U-shaped one-turn coil which shows Example 5 of this invention.   It is sectional drawing which shows the state which welds an aluminum plate (to-be-welded material) using the U-shaped one-turn coil which shows Example 6 of this invention.   It is sectional drawing which shows the state which welds an aluminum plate (to-be-welded material) using the one turn coil comprised from the three flat electric wires which concern on this invention.

DESCRIPTION OF SYMBOLS 1 Flat one turn coil 1a Current concentrated part 1b of flat one turn coil Flat part 1c of flat one turn coil Peripheral part 2 of flat one turn coil Aluminum plate (material to be welded)
3 Fixing plate 4 Insulating material 5 Tightening force (direction)
6 Cooling passage 7 Notch 8 U-shaped one-turn coil 9 Flat wire 9a Flat wire 9b in the center Flat wire 10 on both sides Short-circuit copper plate

Claims (6)

An electrically isolated metal plate with a narrow current-concentrating part for processing current from the power source by processing a highly conductive metal plate and a wide remaining part for supplying return current. An electromagnetic welding apparatus for horizontally placing a thin metal plate on a flat one-turn coil surface composed of a single plate, energizing the coil from a power source to generate electromagnetic force, and welding the thin metal plate by this electromagnetic force In
The cross-sectional shape in the direction perpendicular to the current of the current concentration portion is rectangular, the cross-sectional width (horizontal direction) of this current concentration portion is 1/10 or less than the coil plate thickness, and between this current concentration portion and the remaining portion, A flat plate one-turn coil and a fixing method characterized in that an insulating material having a cross-sectional width equal to or larger than a cross-sectional width of a current concentration portion and having the same thickness as a coil plate is inserted and the current concentration portion is fixed.   The flat one-turn coil and fixing method according to claim 1, wherein a cross-sectional width of the current concentration portion is 1 mm or less and a coil plate thickness is 10 mm to 20 mm.   2. The flat plate one-turn coil and fixing method according to claim 1, wherein a cooling passage penetrating the inside of the flat plate one-turn coil including the insulating material and the current concentration portion is provided in a horizontal direction. A U-shaped one-turn coil, in which two highly conductive flat rectangular wires are reciprocated in parallel, is electrically insulated, and a thin metal plate is placed horizontally between these coils (flat electric wires), and this coil is turned off from the power source. In an electromagnetic welding device for generating an electromagnetic force by energizing the metal plate and welding the metal thin plate by this electromagnetic force,
The cross-sectional shape of the flat electric wire is rectangular, the cross-sectional width (horizontal direction) of at least one flat electric wire is 1/10 or less than the vertical cross-sectional width (vertical direction), and insulation is placed on both sides of the flat electric wire in the horizontal direction. A U-shaped one-turn coil and a fixing method characterized by fixing a flat electric wire.   5. The U-shaped one-turn coil and fixing method according to claim 4, wherein the at least one rectangular electric wire has a cross-sectional width of 1 mm or less and a cross-sectional length of 10 mm to 20 mm. A one-turn coil with a structure in which one surface of three rectangular cross-sectionally well-conducting rectangular wires is aligned with the same horizontal plane, arranged in parallel, and the current going to the central rectangular wire is sent to the rest of the rectangular wires. Electromagnetically insulates and places the stacked thin metal plates horizontally on the matching surface of the coil, energizes the coil from a power source to generate electromagnetic force, and this electromagnetic force welds the thin metal plate. In welding equipment,
The horizontal width of the central flat electric wire is 1 mm or less, the vertical width of the cross section is 10 mm to 20 mm, the horizontal width of the remaining flat electric wire is 30 mm or more, and the vertical width of the cross section is 1 mm to 5 mm. A one-turn coil composed of three rectangular electric wires and a fixing method, characterized in that an insulating material is placed on the middle and the central rectangular electric wire is fixed.

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