JP6612098B2 - Metal bonding wire manufacturing method and die - Google Patents

Description

  The present invention relates to a metal bonding wire used for bonding a winding wire and a lead wire connected to a terminal in a rotating machine such as an electric motor or a generator, a device such as a transformer, and a manufacturing method thereof, and in particular, the diameter or width of the wire. The present invention relates to a technique for connecting metal materials of the same type or different types different from each other.

  In general, windings used for devices such as motors and generators such as rotating machines and transformers are connected to lead wires that are pulled out of the equipment, and are connected to glass terminals provided in sealed containers via connectors. The The winding and the lead wire are connected by welding, soldering, or a press contact terminal (see, for example, Patent Document 1, page 3-4, Fig. 1-3).

  As the winding wound around the internal iron core, a copper wire having a low electrical resistance is generally used. However, for the purpose of cost reduction, a wire other than a copper wire such as an aluminum wire may be used (for example, Patent Document 2, page 4). reference).

  Using a taffled wire, which is a cold-welded aluminum wire and copper wire, between the winding and the terminal, the aluminum wire side of the tuffed wire is welded or soldered to the winding, and the copper side of the taffled wire is copper It is joined with a copper lead wire connected to the terminal and a pressure contact terminal.

JP 2001-197699 A JP 2008-173001 A JP-A-8-57662 JP-A-8-164436

  The windings in sealed containers such as conventional electric motors and generators, transformers, etc. and the lead wires drawn from the containers are connected by connecting members such as soldering, brazing, or pressure contact terminals. It is common. When an aluminum wire is used for the winding, the electrical resistance is higher than that of the copper wire, and the winding temperature rises. Since the iron core is heated by the winding, the electric motor and the transformer are used under a higher temperature condition than before.

  When the operating temperature of the motor or transformer rises, the crimping terminal that connects and fixes the winding and lead wires loosens the winding and lead wires due to the difference in the coefficient of thermal expansion of the material of each part. There was a problem that the electrical contact between the wire, the lead wire, and the press contact terminal was lowered, and the electrical resistance at the connection portion was increased. And if the electrical resistance at the connection part increases, the efficiency of the equipment will be reduced, the temperature of the connection part will rise, and the thermal expansion of the winding, lead wire and press contact terminal will be promoted, and further the winding and lead wire will There was a problem that the fixed state increased the looseness. In particular, when the material of parts is different, such as copper material, brass material, and aluminum material, the difference in thermal expansion coefficient of each material is large, so that there is a problem that looseness is large and electrical resistance is likely to increase.

  Also, when the winding and lead wire are soldered or brazed, the winding and lead wire are connected via solder or brazing material, so the electrical resistance of the connection part is the material of the winding or lead wire There is a problem that the efficiency of the device is lowered and the temperature of the connection portion is increased. Generally, the connection part connected by soldering or brazing is protected from contact with other conductors by a protective member such as a sleeve, but in the control of flowing a large current such as vibration suppression control or field weakening control. Further, since the temperature rise of the connecting portion is also increased, there is a problem that the protective member also needs high heat resistance.

  In addition, an oxide film is formed on the surface of the winding and lead wires, and soldering and brazing are due to the wetting phenomenon between the base material and the molten metal, so flux is used to chemically remove the oxide film To do. However, if flux remains in the joints, the windings or lead wires are corroded, and foreign substances such as sludge are generated due to chemical reaction with the refrigerant or refrigerating machine oil. There is a risk of clogging the throttle valve. For this reason, there is a problem that an increase in manufacturing cost and a decrease in productivity are caused, for example, it is necessary to add a cleaning process. In particular, a material having a strong oxidizing action such as an aluminum material has a problem that the action of the welding flux for removing the oxide film becomes strong, so that the corrosiveness becomes high and the necessity for cleaning becomes high.

  In order to solve these problems, in joining aluminum wires and lead wires connected to copper terminals, they are joined without increasing the electrical resistance of the joint, and foreign matter such as sludge is generated from the joint. A cold pressure welding method is also used in which it is suppressed. However, in the cold welding method, it is possible to join wires having the same diameter or width, and it is not possible to directly join a copper lead wire connected to a terminal and an aluminum winding having a different diameter or width. was there. For this purpose, a taffled wire in which an aluminum wire and a copper wire are joined by cold welding is used between the winding and the terminal, and the aluminum wire side of the taffled wire is welded or soldered to the same aluminum winding. Then, the copper wire side of the taffried wire is joined to the copper lead wire connected to the terminal made of the same material by the press contact terminal. Accordingly, there is a complicated process in which there are three joint portions between the winding and the lead wire connected to the terminal, which causes an increase in process time and cost.

  An object of the present invention is to provide a metal bonding wire obtained by directly bonding different types or types of metal wires having different diameters or widths by a cold pressure welding method and a manufacturing method thereof.

In order to solve the above problems, for example, the configuration of the claims is adopted.
The present application includes a plurality of means for solving the above-mentioned problems. To give an example of the method for producing a metal bonding wire of the present invention, a pair of pair dies supports two metal wires having different diameters or widths, and is cooled. A method of manufacturing a metal bonding wire that is joined by inter-pressure welding, wherein two metal wires having different diameters or widths are supported on the pair of pair dies, and the two metal wires having different diameters or widths are arranged to face each other. And a step of moving the pair of dies, pressing the two metal wires having different diameters or widths to cause plastic deformation by compression, and causing a contaminated layer such as an oxide film on the metal surface to be outside by plastic flow. A step of performing cold pressure welding by bringing the atoms present in the extruded new surface into contact with each other, further moving the pair of pair dies, and arranging a large diameter or width on the outside Restraining portion of the Peadaisu restraining the outer circumference of the metal wire, comprising the steps of removing the burrs extruded outward, and as the pair of Peadaisu, restraint portion of the Peadaisu diameter or restraining the large wire widths, It protrudes by a predetermined distance from the contact part with another pair die, and the restraint part of the pair die that restrains the wire having a small diameter or width is a predetermined distance from the contact part with another pair die. It is characterized by using a retracted one.

Further, as an example of the die of the present invention, a die composed of a pair of pair dies for joining two metal wires having different diameters or widths by cold pressure welding, the two pair dies being ends facing the other pair dies. The portion is provided with a restraining portion for restraining the outer periphery of the metal wire, and the angle of inclination of the end of the restraining portion of the metal wire having a small diameter or width is larger than the angle of inclination of the end of the restraining portion of the wire having a large diameter or width. However, the constraining portion of the wire rod having a large diameter or width protrudes by a predetermined distance from the abutting portion with another die, and the constraining portion of the wire rod having a small diameter or width comes into contact with another die. It is characterized in that it is pulled in a predetermined distance rather than the part .

  ADVANTAGE OF THE INVENTION According to this invention, the metal joining wire which joined the dissimilar or same kind metal wire from which a diameter or a width | variety differs directly by the cold pressure welding method, and its manufacturing method can be provided.

  And it can join without increasing the electrical resistance of a joined part, and can obtain a metal bond line with high reliability which controlled generating foreign matters, such as sludge, from a joined part.

It is a figure which shows an example of the transformer using the metal joint line which concerns on Embodiment 1 of this invention, and the expanded cross section of a metal joint line. It is a figure which shows the different diameter (or width) of Embodiment 1, and the metal joining line of a different cross-sectional shape. It is an external appearance perspective view of the die | dye which concerns on Embodiment 2 of this invention. It is a top view of the die | dye which concerns on Embodiment 2 of this invention. It is a figure which shows the manufacturing method of the metal joining wire which concerns on Embodiment 3 of this invention. It is a figure which shows the manufacturing method of the metal joining wire which concerns on Embodiment 3 of this invention. It is a figure which shows the manufacturing method of the metal joining wire which concerns on Embodiment 3 of this invention. It is an external appearance perspective view of an example of a well-known cold press machine. It is sectional drawing of the cold pressure welding machine of FIG. It is an external appearance perspective view of the conventional die. It is a figure which shows the portable electric type cold pressure welding machine which concerns on Embodiment 4 of this invention. It is a figure which shows an example of a well-known portable cold press machine.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that components having the same function are denoted by the same names and reference numerals as much as possible in the drawings for describing the embodiments, and the repetitive description thereof is omitted.

(Embodiment 1)
Here, the same or different metal joint lines in the lead wires connecting the windings and the terminals will be described using a transformer as an example.

  FIG. 1 shows the same or different metal joint lines in a lead wire connecting a winding and a terminal inside a transformer container in Embodiment 1 of the present invention. The transformer 1 shown in FIG. 1 requires an iron core 4 that constitutes a magnetic path, a winding 2 that constitutes an electric circuit, and a lead wire 3 in order to perform its function. It is assembled using various insulating materials 5 so that it can be operated without abnormality even when a high voltage is applied. In addition, these assemblies are fixed to the tank, and insulators such as a low pressure bushing 8 and a high pressure bushing 9 are used to safely connect to an external electric wire via the connector 7.

  Here, the winding 2 is generally made of a copper wire, but some of the wire 2 uses an aluminum wire for cost reduction. When an aluminum wire is used as the winding 2, it is necessary to join a copper lead wire connected to the connector with a wire having a different diameter (or width) and material. For this reason, conventionally, at least three joints are used between the winding 2 made of an aluminum material and the lead wire 3 made of a copper material connected to the connector 7. Since the wire diameter (or width) and material are different as normal joining methods, there are a method of melting and joining materials at high temperature such as welding, soldering, brazing and a method of connecting and fixing by pressing pressure of a pressure contact terminal. It is used.

  However, when an aluminum wire is used, a conductive wire having the same wire diameter (or width) as copper has an electric resistance of about 1.6 times that of the copper wire. If the load of the transformer does not change, the current flowing through the winding 2 does not change. Therefore, even when an aluminum wire is used for the winding 2, it is necessary to pass the same amount of current as when a copper wire is used. When a necessary current is passed, Joule heat generated by a winding using an aluminum wire is increased as compared with a winding using a copper wire, so that the operating temperature of the aluminum wire is higher than that of the copper wire. That is, the upper limit value of the temperature rise of the winding 2 is increased. In order to suppress the temperature rise of the winding 2, there is a method of increasing the wire diameter (or width) of the winding 2 and reducing the electrical resistance. However, since the load required by the transformer does not change, the same number of windings are required to ensure the same amount of magnetic flux generated in the iron core 4, and the entire container for storing the winding 2 becomes large. Therefore, there is a limit to the method of suppressing the temperature rise by increasing the diameter (or width) of the winding 2 and reducing the electrical resistance. Therefore, there is a problem in using the copper wire and the aluminum wire at the same operating temperature.

  On the other hand, when the temperature of the winding becomes high, the electrical resistance of the connection portion where the winding 2 and the lead wire 3 are soldered or brazed becomes higher than that of the winding material or the lead wire, and the efficiency of the transformer 1 is reduced. As a result, the temperature of the connecting portion increases. In addition, an oxide film is formed on the surface of the winding 2 and the lead wire 3, and flux is used to chemically remove the oxide film during soldering or brazing. If they remain, the winding 2 or the lead wire 3 may be corroded, or foreign substances such as sludge may be generated due to a chemical reaction with the insulating oil in the transformer, leading to problems. Further, in a general method of connecting and fixing the winding 2 and the lead wire 3 by the pressing force of the press contact terminal, the connection is fixed due to the difference in thermal expansion coefficient of the metal used for the winding 2, the lead wire 3 and the press contact terminal. The part is deformed, the fixed state of the winding 2 and the lead wire 3 is loosened, the electrical contact state is deteriorated, and the electrical resistance is increased. Therefore, although it was not a problem in the conventional temperature condition, even if an element that requires an expansion of the upper limit of the temperature condition was introduced and the insulation type was changed to a high-temperature rank accordingly, the connection between the winding 2 and the lead wire 3 There is a problem of strength reliability in the part, and there is a case where sufficient ability cannot be exhibited. Therefore, in recent years, a method using cold pressure welding in which the connection state between the winding 2 and the lead wire 3 does not change with respect to a temperature change has been studied.

  Cold welding is a bonding state in which atomic bonding is caused between the metals by pressurizing and deforming the metal material. Normally, the inside of a metal is in a state of being regularly aligned and bonded by the action of electrons that travel around the nucleus, but the atoms that are aligned on the surface of the metal are in an unstable state (activated state) with no partner on the outside. For this reason, it is combined with oxygen atoms in the air to form a stable state, that is, an oxide film. Normally, even if metal materials are brought into contact with each other, since there is an oxide film, a bonding state that causes an atomic bond between the metals does not occur, but oxygen atoms are removed from the surface metal (oxide film is removed) When metals whose surfaces are activated are brought into contact with each other, even if different types of metals are brought into contact with each other, atomic bonds are caused by the action of electrons around the nucleus and bonded.

  In cold welding, metal wires are brought into contact with each other, and plastic deformation is intentionally caused by compression, and a contaminated layer such as an oxide film on the metal surface is stretched by plastic flow, thereby contaminating the contact surfaces of both metals. Causes the layer to crack. The active metal that does not touch the atmosphere called the new surface is pushed out from the crack. A method of causing metal bonding by bringing atoms present on the new surface extruded from both metals closer to 10 A (angstrom) or less is used. When this method is used, the above-described problem in strength reliability of the joint can be solved.

  In the present invention, by using the above-mentioned cold welding, the diameters of both metal wires between the same type metal wires or different types of metal wires (for example, the copper lead wire 3 connecting the aluminum winding 2 and the connector 7) ( (Or width), the inclination of the end of the device that constrains the outer periphery of each is changed to join metal wires having different diameters (or widths) and different cross-sectional shapes.

  FIG. 1 shows an enlarged cross-sectional view of a metal bonding line 10 formed by bonding metal wires 12 and 13 having different diameters (or widths) 12a and 13a bonded by the cold welding method of the present invention. In the joining portion 10a of the metal joining wire 10, the end portion of the metal wire 12 having the smaller diameter (or width) is larger than the original diameter 12a (or width) of the metal wire 12 having the smaller diameter (or width). It has the site | part 10b currently formed in the diameter 12b, It is characterized by the above-mentioned. As shown in the drawing, the diameter 12b of the portion 10b of the metal wire 12 that is larger than the original diameter 12a is substantially the same as the diameter 13b of the metal wire 13 having the larger diameter. In FIG. 1, the metal joint wire 10 is used for connection between the winding 2 of the transformer 1 and the lead wire 3 connected to the terminal. Similarly, in a rotating machine such as an electric motor or a generator, it can be used for connection between a winding and a lead wire connected to a terminal.

FIG. 2 shows metal joint lines having different diameters (or widths) and different cross-sectional shapes joined by the cold welding method. In FIG. 2A, a metal wire 12 having a smaller diameter is joined to a metal wire 13 having a larger diameter by a cold pressure welding method. A portion 10b having a large diameter is provided.
FIG. 2B shows a case where a rectangular metal wire 12 having a small width is joined to a circular metal wire 13 having a large diameter by a cold pressure welding method. A portion 10b having a large diameter is provided.
FIG. 2C shows a case where a circular metal wire 12 having a small diameter is joined to a rectangular metal wire 13 having a large width by a cold pressure welding method. A portion 10b formed with a large width is provided.
Different cross-sectional shapes may be various shapes such as a circle, an ellipse, a polygon, and a non-circle.

  According to the present embodiment, it is possible to provide a metal bonding wire obtained by directly bonding different types or types of metal wires having different diameters or widths by a cold welding method. And this metal joining wire can be used for joining windings and lead wires connected to terminals in devices such as rotating machines and transformers such as electric motors and generators, improving the reliability of the device and the number of parts. The manufacturing process can be simplified and the cost can be reduced.

(Embodiment 2)
In the second embodiment, an apparatus for manufacturing a metal joining wire joined by a cold welding method will be described. As a conventional cold pressure welding machine for manufacturing the metal joining wire 10, for example, one disclosed in Japanese Patent Application Laid-Open No. 8-57662 (Patent Document 3) is known. As shown in FIGS. 5 and 6, two V blocks 16 (FIG. 6) arranged opposite to each other on the upper part of the frame 15 are provided, and a pair of dies 17 are incorporated between the two V blocks 16. is there. By rotating a lever 18 (FIG. 5) pivotally supported by the frame 15, both V blocks 16 are pressed against each other, and the wire rods supported by the pair of dies 17 are pressed against each other.

  FIG. 7 shows the appearance of the pair of dies 17. The die 17 is composed of four die pieces 17a to 20a, and by combining the two die pieces 17a and 18a, a die hole 21a for sandwiching one wire is formed, and the remaining two die pieces 19a and 20a are formed. By combining them, a die hole 21b for sandwiching the other wire is formed. Pins 22 are disposed between adjacent die pieces, and ends of the pins 22 are inserted into the die pieces 17a to 20a, respectively. Then, the screw 23 is screwed into the pin 22 to connect the die pieces 17a to 20a so that each die piece can slide along the pin. In addition, the circular hollow formed in the periphery of the die holes 21a and 21b is a gap 24 for releasing a burr generated at the time of press contact.

  The die 17 is assembled into the V block 16 so that the inclined surface (side surface) 25 of the die piece abuts on the inclined surface of the V block 16. When the V block 16 is pressed, each die piece is pressed in the pressing direction to sandwich the wire, and further slides along the inclined surface of the V block so as to be in the die hole axial direction (direction orthogonal to the V block pressing direction). Is also pressed.

  When the cam 18 is rotated by operating the lever 18, the roller 27 provided on the yoke 31 is released from the concave portion of the cam 28 and comes into contact with the convex portion, and one end of the rocker arm 33 is expanded. The rocker arm 33 acts as a lever around the rotation shaft 29, the other end of the rocker arm on the V block 16 side moves to the center side, and presses both the V blocks 16. The pair of dies 17 moves and the two wire rods supported by the die hole 21a and the die hole 21b are pressed at the center of the frame, whereby the two wire rods are cold-welded.

  FIG. 3A shows a schematic perspective view of a die of the present invention used in a cold welding machine for manufacturing the metal bonding wire 10 of the present invention. The die for cold welding includes a pair die that forms a die hole with a pair of die pieces 17a and 18a, and a pair die that forms a die hole with another pair of die pieces 19a and 20a. A pair die formed by a pair of die pieces 17 a and 18 a supports the wire 13, and a pair die formed by another pair of die pieces 19 a and 20 a supports the wire 12. Each pair die is provided with restraining portions 37 and 38 for restraining the outer periphery of the wire according to the diameter (or width) of the wire to be supported at the end facing the other pair dies, as will be described later. Depending on the diameter (or width) of the wire rod, the angles of the end slopes 37a and 38a of the restraint portion are changed. In the figure, reference numeral 24 is a recess around the restraining portions 37 and 38 provided on the die, and reference numerals 35 and 36 are contact portions with other paired dies.

  FIG. 3B shows a detailed cross-sectional view in which the pair of pair dies of FIG. 3A are arranged to face each other. The pair die formed by the die pieces 17a and 18a and supporting the wire rod 13 having a large diameter (or width) includes a restricting portion 37 at the tip, and the angle of the end slope 37a of the restricting portion 37 is α1. Moreover, the pair die which is configured by the die pieces 19a and 20a and supports the wire 12 having a small diameter (or width) includes the restraining portion 38 at the tip portion, and the angle of the end slope 38a of the restraining portion 38 is α2. . Here, the angles α1 and α2 of the end inclination are angles from the axial direction (pressing direction) of each wire to the end inclination of the restraint. The angle α2 of the end portion inclination 38a of the restricting portion 38 is larger than the angle α1 of the end portion inclination 37a of the restricting portion 37. By making the angle α2 of the end slope 38a of the restraining portion 38 of the wire 12 having a small diameter (or width) larger than the angle α1 of the end slope 37a of the restraining portion 37 of the wire 13 having a large diameter (or width), When wires having different diameters or widths are cold-welded, plastic deformation is intentionally caused by compression, and a contaminated layer such as an oxide film present on the metal surface can be drawn outside by plastic flow. The angle α1 is 5 ° to 45 °, more preferably 15 ° to 45 °. The angle α2 is 45 ° to 90 °, more preferably 65 ° to 85 °.

  Moreover, as shown in the drawing, the constraining portion 37 of the wire 13 having a large diameter (or width) protrudes by a predetermined distance d1 from the contact portion 35 with other paired dies. On the other hand, the restraining portion 38 of the wire 12 having a small diameter (or width) is drawn by a predetermined distance d2 from the contact portion 36 with another pair die. With this configuration, as described in the third embodiment below, when cold-welded wires having different diameters or widths are plastically flowed to the outside by the restraining portion 37 of the wire 13 having a large diameter (or width). Can remove Bali.

  According to the dice described in the present embodiment, it is possible to manufacture a metal bonding wire obtained by directly bonding different types or types of metal wires having different diameters or widths by a cold welding method. A highly reliable metal bonding wire that is bonded without increasing the electrical resistance of the bonding portion and suppresses generation of foreign matters such as sludge from the bonding portion can be manufactured at a reduced cost.

(Embodiment 3)
In Embodiment 3, a method for manufacturing a metal bonding wire of the present invention will be described. 4A to 4C show a method for manufacturing the metal bonding wire 10 of the present invention using the dice described in the second embodiment.

  First, as shown in FIG. 4A, a pair of dice pieces 17a and 18a constitute a die hole to support a metal wire 13 having a large diameter or width, and a pair of die pieces 19a and 20a constitute a die hole. The metal wire 12 having a small diameter or width is supported by the pair die. Then, both pair dies are made to face each other, and the metal wire 13 and the metal wire 12 are brought into contact with each other. As described with reference to FIG. 3B, the angle α2 of the end slope 38a of the restraining portion 38 of the wire 12 having a small diameter (or width) is equal to the end slope 37a of the restraining portion 37 of the wire 13 having a large diameter (or width). It is larger than the angle α1. Further, the constraining portion 37 of the wire 13 having a large diameter (or width) protrudes by a predetermined distance d1 from the contact portion 35 with another pair die. On the other hand, the constraining portion 38 of the wire 12 having a small diameter (or width) is drawn by a predetermined distance d2 from the contact portion 36 with another pair die.

  Next, as shown in FIG. 4B, both pair dies are moved, and the metal wire 13 and the metal wire 12 are pressed to perform cold welding. As shown in the enlarged view of the figure, when the metal wire 13 and the metal wire 12 are pressed, plastic deformation is caused by compression, and changes in the end slopes 37a and 38a of the restraint portions 37 and 38 that restrain the outer periphery of the metal wire ( The angle α2 of the end slope 38a on the side with the smaller diameter of the metal wire is larger than the angle α1 of the end slope 37a on the side with the larger diameter of the metal wire), so that the contaminated layer such as an oxide film on the metal surface is plastic. It is stretched to the outside by the flow and becomes a burr 39 and comes out to the outside. And in the press part of the metal wire 13 and the metal wire 12, cold pressure welding is performed because the atoms which exist in the extruded new surface approach.

  When the pair dies are further moved, as shown in FIG. 4C, the contact portions 35 and 36 of the pair dies come into contact with each other. At this time, the constraining portion 37 of the wire 13 having a large diameter (or width) protrudes by a predetermined distance d1 from the contact portion 35 with another die, and constrains the wire 12 having a small diameter (or width). Since the portion 38 is pulled in by a predetermined distance d2 from the contact portion 36 with other dies, a restraining portion 37 that restrains the outer periphery of the metal wire 13 having a large diameter (or width) disposed outside. Removes Bali 39. In this case, since the angle α1 of the end slope 38a on the side where the diameter of the metal wire is large is small, it is easy to remove the burr.

  According to the method for manufacturing a metal bonding wire described in the present embodiment, it is possible to manufacture a metal bonding wire obtained by directly bonding different types or the same type of metal wires having different diameters or widths by a cold welding method. A highly reliable metal bonding wire that is bonded without increasing the electrical resistance of the bonding portion and suppresses generation of foreign matters such as sludge from the bonding portion can be manufactured at a reduced cost.

(Embodiment 4)
The present invention can be used for a portable cold pressure welding machine described in, for example, Japanese Patent Application Laid-Open No. 8-164436 (Patent Document 4), in addition to the installation type cold pressure welding machine described in the second embodiment. In the present embodiment, using the electric function, control is performed to change the stroke of the pressure contact in accordance with the change in the diameter of the metal wire and the change in the cross-sectional area.

  In FIG. 9, the top view of the portable cold press machine of patent document 4 is shown. In this cold pressure welding machine, the pressure welding stroke is operated by hand force using the lever 40 and the grip portion 41. On the other hand, in the portable conductive cold pressure welding machine according to the fourth embodiment shown in FIG. 8, when the switch unit 42 is pressed, the control base 43 and the power source unit 44 operate the pressure welding stroke. Further, the switch unit 42 is switched according to the diameter (width) of the metal wire.

  The portable electric cold pressure welding machine of the present embodiment is also provided with the dice shown in FIGS. 3A and 3B, and the same effects as described in the second embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 Transformer 2 Winding 3 Lead wire 4 Iron core 5 Insulating material 7 Connector 8 Low voltage bushing 9 High voltage bushing 10 Metal joint wire 10a Metal joint wire joint 10b The part 12 formed in the diameter larger than the original width of the metal wire 12 Small diameter metal wire 12a Diameter 12b of metal wire 12b Diameter 13 larger than original diameter 12a of metal wire 12 Large diameter metal wire 13a Diameter of large diameter metal wire 16 V block 17 Dies 17a, 18a, 19a, 20a Die piece 24 Recesses 35 and 36 around the restraint part Abutment parts 37 and 38 of both pair dies Die restraint part 37a and 38a End slope of restraint part restraining the outer periphery of the metal wire 39 Burr of metal wire

Claims (3)

A method of manufacturing a metal joining wire that supports two metal wires having different diameters or widths on a pair of pair dies and joins them by cold welding,
Supporting the two metal wires having different diameters or widths on the pair of pair dies, and placing the two metal wires having different diameters or widths opposite to each other;
The pair of dies are moved, the two metal wires having different diameters or widths are pressed, plastic deformation is caused by compression, and a contaminated layer such as an oxide film existing on the metal surface is pulled out by plastic flow and pushed out. A step of performing cold welding as atoms existing on the newly formed surface approach each other,
The pair of pair dies is further moved, and the restraint part of the pair dies for restraining the outer periphery of the metal wire having a large diameter or width disposed on the outside includes a step of removing the burrs pushed outward ,
As the pair of pair dies, the pair die restricting portion that restricts a wire having a large diameter or width protrudes by a predetermined distance from the contact portion with another pair die, and restricts a wire having a small diameter or width. The method of manufacturing a metal bonding line, wherein the pair die restricting portion is a portion that is pulled in a predetermined distance from a contact portion with another pair die . It is a manufacturing method of the metal joining wire according to claim 1 ,
As the pair of dies, the angle of inclination of the end portion of the restraining portion of the pair die that restrains a metal wire having a small diameter or width is greater than the angle of inclination of the end portion of the restraining portion of the pair die that restrains a wire having a large diameter or width. The manufacturing method of the metal joining wire characterized by using the enlarged thing. A die composed of a pair of pair dies for joining two metal wires having different diameters or widths by cold welding,
Both the pair dies are provided with a restraining portion for restraining the outer periphery of the metal wire at the end facing the other pair dies,
The angle of the end inclination of the constraining portion of the metal wire with a small diameter or width is made larger than the angle of the end inclination of the constraining portion of the wire with a large diameter or width ,
The constraining portion of the wire rod having a large diameter or width protrudes by a predetermined distance from the contact portion with the other die, and the constraining portion of the wire rod having a small diameter or width is more than the contact portion with the other die. Also, a die that is retracted by a predetermined distance .

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