JP6288932B2 - Connection structure of electric wire and terminal - Google Patents

Description

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

  Electric wires for connecting to other related electric devices are joined to terminals such as connector terminals housed in the connector housing and connection terminals fixed to the terminals of the electric devices by screws or the like. 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 electric devices or space saving around those devices, it is required to reduce the dimensions of the joint portion between the terminal and the electric wire, particularly the length in the electric 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.

JP 2004-311061 A

  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 joint structure of an electric wire and a terminal that can shorten the dimension of the joint portion between the electric wire and the terminal in the electric 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-bonding portion having a bonding surface orthogonal to the extending direction of the terminal formed at one end of the terminal, and the wire-insulating coating on the bonding surface It is characterized in that it has a joining structure in which the tip of the core wire part from which is peeled is ultrasonically joined.

  According to such a joining structure, the length of the joining portion between the wire and the terminal in the wire length direction is the core wire portion (hereinafter referred to as the insulation coating) peeled off from the thickness of the member (for example, plate material) of the wire joining portion of the terminal. As appropriate, the total length with the length of the core wire portion) can be 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, it is preferable that end processing such as forming, press molding, ultrasonic bonding, or the like for forming the cross section of the core wire portion into a predetermined shape (for example, a rectangle) in advance is performed before ultrasonic bonding to the bonding surface. . 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 the recessed part which can mount | wear with the front-end | tip of a core wire part is formed in the joining surface of the electric wire junction part of a 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 a cross section of the core portion into a rectangle may be performed, but such terminal processing may not be performed.

  ADVANTAGE OF THE INVENTION According to this invention, the dimension of the electric wire length direction of the junction part of an electric wire and a terminal can be shortened, and the junction part of the stable property can be formed.

It is a figure explaining the junction structure of the electric wire and terminal of Example 1 of the present invention. It is a figure which shows the shape of Example 2 of the core wire part of the electric wire of this invention. It is a figure explaining the junction structure of the electric wire and terminal of Example 3 of the present invention.

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

  FIG. 1 is a diagram showing a first embodiment of a joining structure formed by ultrasonically joining an electric wire 20 to a male terminal 10 of a connector. FIG. 1 (a) is a state diagram before joining, and FIG. 1 (b). Is a state diagram after joining, and FIG. 8C is a cross-sectional view in the electric wire length direction. 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 by a screw or the like.

  As shown in FIG. 1, the male terminal 10 includes a contact portion 11 that is inserted into the female terminal using a band-shaped metal plate, and a wire joint portion 12 to which the electric wire 20 is joined. The tip of the contact portion 11 has a pointed cross section so that it can be easily inserted into the female terminal of the mating connector. Moreover, the electric wire joining part 12 is bent and formed in the direction orthogonal to the extending direction of the contact part 11, and the joining surface 13 is formed in the back surface side of the electric wire joining part 12 in Fig.1 (a), (b). . 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 the insulation coating 22 of the edge part joined with the male terminal 10 is peeled, and the core wire part 23 is exposed.

  The male terminal 10 and the electric wire 20 formed in this way are pressed against the joint surface 13 of the male terminal 10 against the joint surface 13 of the male terminal 10 as shown in FIG. As is well known, ultrasonic vibration is applied to the boundary between the front end surface of the portion 23 and ultrasonic bonding is performed 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 a of the member of the electric wire joint portion 12 and the length b 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 b of the core wire portion 23 can be made sufficiently short so that the insulating coating is not caught between the bonding surfaces. As a result, the length b of the core wire portion 23 can be sufficiently shortened compared to the case of crimp bonding or conventional ultrasonic bonding, so that 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 pressure contact as in friction welding, it is possible to simplify measures against fraying of the core wire 21 and twisting of the electric wire itself, and a stable property joining structure can be obtained.

  The joining structure of the electric wire and the terminal of Example 1 can be manufactured by a known ultrasonic joining. For example, the joint surface 13 of the male terminal 10 is placed and fixed on a pedestal called an anvil, and the distal end surface of the core wire portion 23 of the electric wire 20 is pressed against the joint surface 13 to at least the core wire portion 23. Ultrasonic waves are applied through an ultrasonic horn equipped with an ultrasonic transducer. As a result, ultrasonic vibration parallel to the boundary surface between the joint surface 13 and the front end surface of the core wire portion 23 is applied, and the oxide film or the like on the metal surface is removed by friction generated on the boundary surface. The metal molecules appear, and further, the metal atoms are diffused by receiving ultrasonic vibration and are solid-phase bonded by atomic bonds.

  Thus, 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 can be suppressed to the sum of the thickness a of the member of the electric wire joint portion 12 and the length b in the electric wire length direction of the core wire portion 23 from which the insulation coating has been peeled off. it can. As a result, the length b of the core wire portion 23 can be sufficiently shortened compared to the case of crimp bonding or conventional ultrasonic bonding, so that 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.

  In FIG. 2, the structure of the core part 26 of the electric wire 20 used for the connection structure of the electric wire of Example 2 of this invention and a terminal is shown. 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. That is, the core wire portion 26 of the present embodiment is formed by forming a cross section at the tip of the core wire portion 26 into a rectangle (in the illustrated example, a square) by terminal processing such as forming. 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. Note that the ultrasonic bonding structure of the second embodiment can be manufactured by applying a known method in the same manner as described in the first embodiment.

  With reference to FIG. 3, Example 3 of the joining structure formed by ultrasonically joining the electric wire 20 to the male terminal 10 will be described. 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. 4C is a state diagram after joining, and FIG. 4D 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 the present embodiment has a depth d 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 becomes the sum of the length b of the wire length direction of the core wire part 23 from which a and the insulation coating were peeled off. Note that the ultrasonic bonding structure of the third embodiment can be manufactured by applying a known method in the same manner as described in the first embodiment.

  According to the third embodiment, since 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 and 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 cross section of the tip of the core wire 21 into a rectangle as in the second embodiment. In addition, while forming the cross section of the recess 17 in a rectangular shape, it is also possible to perform a terminal process for forming or pressing the cross section of the tip of the core wire 21 into a rectangular shape. 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.

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 (2)

Wire bonding portion having a bonding surface that is orthogonal to the extending direction of the terminal is formed at one end of the terminal, Ri Na insulating coating of the electric wire is pressed against the front end face of the core part which is peeled is ultrasonically bonded to the bonding surface ,
The distal end portion of the core wire portion has a junction structure of an electric wire and a terminal whose cross section is formed into a rectangular shape and cured in advance before ultrasonic bonding to the bonding surface . Junction structure between the wire and the terminal according to claim 1, the bonding surface of the electric wire joint portion of the terminal, distal end of the core wire portion is characterized in that fitted capable recesses are formed.

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