WO2014168215A1 - Electrical wire, terminal, and joining structure - Google Patents

Abstract

The present invention is characterized by a joining structure resulting from an electrical wire joining section (12) having a joining surface (13) perpendicular to the direction of extension of a terminal (10) being formed at one end of the terminal (10), and the tip of a core wire (23) exposed from an insulating covering (22) of an electrical wire (20) being ultrasonically joined to the joining surface (13).

Description

Connection structure of electric wire and terminal

The present invention relates to a joint structure between an electric wire and a terminal.

¡Connecting terminals, such as connector terminals housed in the connector housing and connection terminals fixed to the terminals of the electrical equipment with screws or the like, are joined with electric wires for connection with other related electrical equipment. Such a joining structure of the electric wire and the terminal is formed by joining the electric wire to the terminal by various methods such as crimp bonding and ultrasonic bonding. For example, crimp bonding is also referred to as caulking bonding, and has a U-shaped crimp connection portion with a pair of crimp pieces facing each other at one end of a terminal, and a core wire from which the wire coating has been stripped is placed on the crimp connection portion. The pair of crimping pieces are caulked to the core wire side and joined. In ultrasonic bonding, for example, a U-shaped connecting portion formed at one end of a terminal is fixed to an anvil (pedestal), a core wire of an electric wire is placed on the connecting portion, and an ultrasonic horn is pushed on the side surface of the core wire. By applying parallel vibration to the joint surface between the core wire side surface and the terminal, the wires and the metal of the terminal are bonded by atomic bonding.

On the other hand, since there is a demand for miniaturization of connectors and electrical devices or space saving around these devices, it is required to reduce the dimensions of the junction between the terminal and the wire, particularly the length in the wire length direction. However, according to the crimp bonding, since it is necessary to secure a bonding area between the terminal and the core wire in order to reduce electric resistance, there is a limit to reducing the dimension in the electric wire length direction of the bonding portion between the electric wire and the terminal. Similarly, in the case of ultrasonic bonding, since the core wire side surface is placed on the U-shaped connecting portion of the terminal and ultrasonic bonding is performed, the dimension of the connecting portion in the length direction of the electric wire becomes a certain value or more. There is a limit to reducing the dimension in the length direction of the wire at the joint between the terminal and the terminal.

On the other hand, according to the method of forming the joint structure between the electric wire and the terminal by friction welding described in Patent Document 1, it is possible to reduce the dimension in the electric wire length direction of the joint portion between the electric wire and the terminal. In other words, friction welding is a method in which the joint surface between the terminal and the core wire cut surface (tip surface) of the electric wire is brought into pressure contact and rotated at a relatively high speed to generate frictional heat on the joint surface. Then, after melting the metal member on the joining surface, the rotation is stopped and the pressure is further applied to join the tip surface of the electric wire and the terminal. In particular, according to the same document, a disk-shaped end having a diameter corresponding to the diameter of the core wire is formed at the tip of the terminal, and the disk surface and the tip surface of the core wire are joined by friction welding. The dimension in the electric wire length direction of the joint part of a terminal and an electric wire can be shortened significantly.

Japanese Unexamined Patent Publication No. 2004-311061

However, if the electric wire side is rotated in order to relatively rotate the electric wire and the terminal by friction welding, there is a problem that the apparatus becomes large because the surroundings of the electric wire must be dealt with. Moreover, since the core wire of an electric wire is generally a stranded wire, the tip end surface of the stranded wire is joined as a rotating surface, so that it is necessary to prevent the stranded wire from breaking. In this regard, according to Patent Document 1, a rib extending on the side surface of the stranded wire is provided on the joint surface on the terminal side, and the tip surface of the stranded wire is covered with the rib. Also, by surrounding the tip of the stranded wire with a ceramic cylinder or conductive cylinder member with the wires and conductors chucked, adhesion of the melt during friction welding is prevented, and the mechanical and electrical connection of the joint In addition to preventing such adverse effects, the invention has been devised to increase heat diffusion during friction welding and heat conduction in residual heat. However, there is a demand for obtaining a stable joint portion that can further suppress fraying of the stranded wire and twisting of the electric wire and efficiently friction-weld with the terminal joint surface.

The problem to be solved by the present invention is to provide a wire-terminal joint structure that can shorten the dimension of the joint portion between the wire and the terminal in the wire length direction and can form a stable joint portion.

In order to solve the above-described problems, the wire-terminal connection structure of the present invention has a wire joint portion having a joint surface orthogonal to the extending direction of the terminal formed at one end of the terminal, and the wire insulation cover on the joint surface. The core wire portion exposed from the tip has a joining structure in which the tip is ultrasonically joined.

According to such a joining structure, the length in the wire length direction of the joining portion between the wire and the terminal is the core wire portion (exposed from the thickness of the member (for example, plate material) of the wire joining portion of the terminal and the insulation coating). Hereinafter, the total length with the length of the core wire portion can be appropriately suppressed. In particular, in the case of ultrasonic bonding, the length of the core wire portion can be sufficiently shortened compared to the case of crimp bonding or conventional ultrasonic bonding so that the insulation coating is not caught between the bonding surfaces. The length in the electric wire length direction can be made sufficiently short. Moreover, since the joint surface is not rotated at high speed while being in pressure contact like friction welding, it is possible to simplify the countermeasures against core wire breakage and fraying and torsion of the wire itself, and to obtain a stable joint structure. Can do.

In this case, terminal processing such as forming, press molding, ultrasonic bonding, or the like for forming the tip of the core wire portion into a predetermined shape (for example, a rectangular parallelepiped shape) in advance is performed before ultrasonic bonding to the bonding surface. preferable. According to this, since the core wire portion is work-hardened by terminal processing, when the core wire is a stranded wire, fraying or bending of the core wire occurs when the end of the core wire portion is abutted against the joint surface of the electric wire joint portion of the terminal. Concerns can be reduced and a stable bonded structure can be obtained.

Moreover, it is preferable that a recess in which the tip of the core wire portion can be fitted is formed on the joining surface of the wire joining portion of the terminal. According to this, fraying or bending of the core wire portion can be prevented by the inner wall of the recess. In this case, terminal processing such as forming for forming the tip of the core wire portion into a rectangular parallelepiped shape may be performed, but such terminal processing may not be performed.

According to the present invention, it is possible to shorten the dimension in the wire length direction of the joint portion between the electric wire and the terminal, and to form a stable joint portion.

Fig.1 (a) thru | or FIG.1 (c) are the figures explaining the joining structure of the electric wire and terminal of Example 1 of this invention. FIG. 2 is a diagram showing the shape of Example 2 of the core portion of the electric wire of the present invention. FIG. 3A to FIG. 3D are views for explaining the joint structure between the electric wire and the terminal according to the third embodiment of the present invention.

Hereinafter, the joint structure between the electric wire and the terminal of the present invention will be described based on examples.

FIG. 1A to FIG. 1C are diagrams showing Example 1 of a joining structure formed by ultrasonically joining an electric wire 20 to a male terminal 10 of a connector, and FIG. FIG. 1B is a state diagram after joining, and FIG. 1C is a cross-sectional view in the length direction of the electric wire. FIG. 2 is a schematic diagram illustrating the configuration and manufacturing procedure of an ultrasonic bonding apparatus that manufactures the bonding structure between the electric wire and the terminal according to the first embodiment. In addition, in the following description, although it demonstrates based on the example which ultrasonically joins an electric wire to the male terminal of a connector, this invention is not restricted to this, When joining an electric wire to the female terminal of a connector, and a board In the case of a needle-like connector terminal instead of a wire, the present invention can be applied to a case where an electric wire is connected to a connection terminal fixed to a terminal of an electric device with a screw or the like.

As shown in FIG. 1 (a), the male terminal 10 has a contact portion 11 to be inserted into the female terminal using a strip-shaped metal plate, and a wire joint portion 12 to which the electric wire 20 is joined. The tip of the contact portion 11 located on the female terminal side of the mating connector (the portion located on the left side of FIG. 1B) is formed in a pointed shape so that it can be easily inserted into the female terminal of the mating connector. Moreover, the electric wire joining part 12 is formed by being bent with respect to the contact part 11 in a direction orthogonal to the extending direction of the contact part 11, and on the back side in FIGS. 1A and 1B of the electric wire joining part 12. A joining surface 13 is formed. That is, the wire joint portion 12 having the joint surface 13 orthogonal to the extending direction of the male terminal 10 is formed at one end of the male terminal 10. The electric wire 20 is formed by covering a core wire 21 formed by combining a plurality of strands with an insulating coating 22. And as for the electric wire 20, the insulation coating 22 is peeled in the edge part joined to the male terminal 10, and the core wire part 23 is exposed. Hereinafter, a part of the core wire 21 exposed from the insulating coating 22 at one end of the electric wire is referred to as a core wire portion 23.

After forming the male terminal 10 and the electric wire 20 in this way, as shown in FIG. 1 (b), the front end surface of the core wire portion 23 of the electric wire 20 is pressed against the joint surface 13 of the male terminal 10. Then, as is well known, ultrasonic vibration is applied to the boundary between the bonding surface 13 and the distal end surface of the core wire portion 23 to perform ultrasonic bonding by atomic bonding. By ultrasonic bonding in this manner, the core wire portion 23 of the electric wire 20 is bonded to the electric wire bonding portion 12 of the male terminal 10 as shown in the cross-sectional view of FIG. The dimension L of the joint portion 25 between the electric wire 20 and the male terminal 10 of the present embodiment is the sum of the thickness La of the member of the electric wire joint portion 12 and the length Lb in the wire length direction of the core wire portion 23 from which the insulation coating has been peeled off. Can be suppressed. In particular, in the case of ultrasonic bonding, the length Lb of the core wire portion 23 can be made sufficiently short to such an extent that the insulating coating is not caught between the bonding surfaces. As a result, since the length Lb of the core wire portion 23 can be sufficiently shortened compared to the case of crimp bonding or conventional ultrasonic bonding, the length L in the wire length direction of the joint portion 25 can be made sufficiently short, It is possible to reduce the size of connectors and electrical devices or save space around those devices. In addition, since the joint surfaces are not rotated at high speed while being brought into press contact with each other as in friction welding, it is possible to simplify measures against fraying of the core wire 21 and twisting of the electric wires themselves, and a stable joint structure can be obtained.

The joint structure between the electric wire and the terminal of the first embodiment is, for example, placed and fixed on a pedestal called an anvil with the joint surface 13 of the male terminal 10 facing up, and the core wire of the electric wire 20 facing the joint surface 13. The tip surface of the portion 23 is pressed, and ultrasonic waves are applied to at least the core wire portion 23 via an ultrasonic horn provided with an ultrasonic transducer. As a result, ultrasonic vibration is applied to the boundary surface between the joint surface 13 and the front end surface of the core wire portion 23 to cause the front end surface of the core wire portion 23 to reciprocate along the boundary surface. The oxide film and the like are removed, clean activated metal molecules appear on the boundary surface, metal atoms are diffused by receiving ultrasonic vibration, and solid-phase bonding is performed by atomic bonding.

In this manner, as shown in the cross-sectional view of FIG. 1C, the core wire portion 23 of the electric wire 20 is abutted and joined to the joint surface 13 of the electric wire joint portion 12. Therefore, the dimension L of the joint portion 25 between the electric wire 20 and the male terminal 10 is suppressed to the sum of the thickness La of the member of the electric wire joint portion 12 and the length Lb in the wire length direction of the core wire portion 23 from which the insulation coating has been peeled off. it can. As a result, since the length Lb of the core wire portion 23 can be sufficiently shortened compared to the case of crimp bonding or conventional ultrasonic bonding, the length L in the wire length direction of the joint portion 25 can be made sufficiently short, It is possible to reduce the size of connectors and electrical devices or save space around those devices. In addition, fraying of the core wire 21 and twisting of the electric wire itself can be prevented, and a bonded portion having stable properties and excellent bonding quality can be formed. In addition, if the ultrasonic bonding is performed by interposing a known serration between the bonding surface 13 of the male terminal 10 and the front end surface of the core portion 23 of the electric wire 20, the reliability of the bonding can be stably secured.

FIG. 2 shows the configuration of the core portion 26 of the electric wire 20 used for the connection structure between the electric wire and the terminal according to the second embodiment of the present invention. The male terminal 10 of the present embodiment is the same as that of the first embodiment, and the shape of the core wire portion 26 of the electric wire 20 is different. In the core wire portion 26 of the present embodiment, the tip end of the core wire portion 26 is formed into a rectangular parallelepiped shape by terminal processing such as forming. That is, the front end surface of the core part 26 is formed in a rectangle (in the illustrated example, a square). According to this, when the core wire 21 is a stranded wire, it is possible to prevent the core wire 21 from fraying or bending when the tip of the core wire portion 26 is pressed against the joint surface 13 of the electric wire joint portion 12 of the male terminal 10. . That is, since the strands of the core wire portion 23 are subjected to work hardening by forming, pressing or ultrasonic bonding, and the core wire 21 can be prevented from fraying or bending, a more stable bonded structure can be obtained. Furthermore, if the front end surface of the core wire portion 26 is formed in a flat shape, no gap is generated between the front end surface and the joint surface 13 when the front end of the core wire portion 26 is pressed against the joint surface 13. An even more stable joining structure can be obtained. The ultrasonic bonding structure of the second embodiment can be manufactured by applying the same method as described in the first embodiment.

Example 3 of the joining structure formed by ultrasonically joining the electric wire 20 to the male terminal 10 will be described with reference to FIGS. 3 (a) to 3 (d). FIG. 3A is a perspective view of the terminal 15 according to the third embodiment as viewed from the opposite side of the joint surface 16, and FIG. 3B is a perspective view of the terminal 15 as viewed from the joint surface 16 side. FIG. 3C is a state diagram after joining, and FIG. 3D is a cross-sectional view in the electric wire length direction. This embodiment is different from the first embodiment in that a recess 17 is formed in the joint surface 16, and the other points are the same as the first embodiment. The recess 17 of this embodiment has a depth Ld at which the tip of the core wire portion 23 can be inserted for a predetermined length, and an inner diameter D that can be fitted.

Since it is formed in this way, as shown in the cross-sectional view of FIG. 3D, the dimension L of the joint portion 28 between the electric wire 20 and the male terminal 10 of this embodiment is the thickness of the plate material of the electric wire joint portion 12. It is the sum of the length Lb in the electric wire length direction of the core wire part 23 from which La and the insulation coating are peeled off. The ultrasonic bonding structure of the third embodiment can be manufactured by applying the same method as described in the first embodiment.

According to the third embodiment, since the ultrasonic bonding can be performed in a state where the tip of the core wire portion 23 is inserted into the recess 17 provided on the bonding surface 16, fraying or bending of the core wire 21 can be further prevented. In the case of the present embodiment, ultrasonic bonding can be performed without forming or pressing the distal end surface of the core wire 21 into a rectangular shape as in the second embodiment. In addition, while forming the cross section of the recessed part 17 in a rectangle, the terminal process which makes the front end surface of the core wire 21 into a rectangle in a rectangular shape and press can also be performed. In this case, the strands of the core wire portion 23 are subjected to work hardening by the terminal treatment, so that the core wire 21 can be further prevented from being frayed or bent.

Here, the features of the above-described embodiment of the joint structure of the electric wire and the terminal according to the present invention are summarized and listed in the following [1] to [3], respectively.

[1] A wire joint (12) having a joint surface (13) orthogonal to the extending direction of the terminal (10) is formed at one end of the terminal (10), and the wire (20) is formed on the joint surface (13). A joining structure of an electric wire (20) and a terminal (10) in which the tip of the core wire portion (23) exposed from the insulating coating (22) is ultrasonically joined.
[2] The electric wire (20) and the terminal (10) according to the above [1], wherein the tip of the core wire portion (23) is molded in a predetermined shape in advance before ultrasonic bonding to the bonding surface (13). Bonding structure with.
[3] The electric wire (20) and the terminal (10) according to the above [1], wherein a recess (17) into which a tip of the core wire portion (23) can be fitted is formed on the joint surface (16). Bonding structure with.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

This application is based on a Japanese patent application filed on April 11, 2013 (Japanese Patent Application No. 2013-083419), the contents of which are incorporated herein by reference.

According to the present invention, it is possible to shorten the dimension of the joint portion between the electric wire and the terminal in the electric wire length direction and to form a stable joint portion. The present invention exhibiting this effect is useful for the connection structure between the electric wire and the terminal.

DESCRIPTION OF SYMBOLS 10 Male terminal 11 Contact part 12 Electric wire junction part 13 and 16 Joint surface 17 Recess 25 and 28 Joint part

Claims (3)

An electric wire joining portion having a joining surface orthogonal to the extending direction of the terminal is formed at one end of the terminal, and an end of the core wire portion exposed from the insulating coating of the electric wire is ultrasonically joined to the joining surface. Construction. The joint structure between an electric wire and a terminal according to claim 1, wherein a tip end of the core wire portion is molded into a predetermined shape in advance before ultrasonic joining to the joining surface. The joining structure of the electric wire and the terminal according to claim 1, wherein a recess in which a tip of the core wire portion can be fitted is formed on the joining surface.

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