JP2004311061A - Connection method between wire conductor and terminal by friction welding - Google Patents

Abstract

An object of the present invention is to provide a method of connecting a wire conductor and a terminal, which is particularly suitable for a W / H wire by a friction welding method.
An electric wire (1) is fixed with an end face of a conductor (2) exposed, and the terminal (3) is rotated while a joining surface of a terminal (3) connected to the conductor (2) of the electric wire (1) and the end face are brought into pressure contact with each other. After securing the desired frictional heat, the terminal 3 is stopped, and the end face of the conductor 2 and the joining surface of the terminal 3 are joined.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of connecting a wire conductor and a terminal by a friction welding method, and particularly to a method of connecting a wire conductor and a terminal suitable for a W / H wire or the like.
[0002]
[Prior art]
As a technique for electrically connecting a terminal and an electric wire, pressure connection and caulking connection are widely used in general. As the press-connecting connection, for example, “pressing an electric wire in manufacturing a wire harness for an automatic worker” described in Japanese Patent Application Laid-Open No. 10-125439 is known. In this technique, as shown in FIG. 5, an electric wire a is pushed into a slot t of a press contact terminal T by a press contact blade 60, and at that time, an insulator covering the electric wire is cut, so that the wire conductor and the press contact terminal are connected to each other. Are brought into contact with each other to thereby obtain conduction.
[0003]
As a crimping connection for crimping a crimp terminal to an end of an electric wire, for example, a "method and a measuring device for dimensions of a terminal crimping portion" described in JP-A-10-89906 is known. According to this technique, as shown in FIG. 6, a height CH and a width CW of a terminal crimping portion d which is a connection portion between a core wire b of an electric wire a and a terminal fitting c are measured, and a crimping connection is performed with an optimal crimp amount. It is a technology to do.
[0004]
The above-described press-connecting and crimping connections have a structure in which current is supplied while maintaining mechanical contact between the electric wire and the terminal. However, there is a structural problem related to mechanical contact. That is, these connections have a problem that the conductor is damaged when the press-contact blade or the caulked portion comes into contact with the conductor, thereby reducing the strength of the conductor. Further, when a contact resistance occurs in a mechanical contact portion, an oxide film is generated due to heat generation, and there is a problem that connection reliability cannot be maintained. Therefore, in order to enhance the reliability of the connection portion, it is necessary to perform a soldering process or a protection process from an oxide film such as gold plating on the connection portion.
[0005]
As a connection method for solving the above-described problem relating to mechanical contact, there is a connection method using friction welding. As this technique, for example, a “method of manufacturing a terminal for a cable terminal” described in Japanese Patent Application Laid-Open No. 7-183056 is known. As shown in FIG. 7, a blade plate portion 12 and a cylindrical cable terminal portion are provided. 14 are separately formed, and both surfaces are rotated while being brought into pressure contact with each other at the position of the bonding portion 18, and the surfaces are bonded by frictional heat generated at that time. Such a method of friction welding of a rod (tube) -shaped metal material is a known technique in which mechanical joining of structural members is performed by welding without using a supply material.
[0006]
[Problems to be solved by the invention]
As described above, in the friction welding, there is no problem related to the mechanical contact structure such as the pressure welding connection and the caulking connection, but it is sometimes difficult to apply the conventional friction welding as it is. That is, in connection by friction welding, the connection members are brought into contact with each other in a pressurized state, and are relatively rotated to generate frictional heat. However. An electric wire for W / H (wire harness) having a structure in which strands are twisted has a low rigidity of the conductor, and the conductor loses the butt pressure at the time of friction welding, and may buckle (break).
[0007]
In order to withstand the butt pressure, as shown in FIG. 7, a sleeve-type terminal wire receiving portion may be provided to secure the rigidity of the conductive wire. In this structure, the wire conductor is inserted into and joined to the terminal wire receiving portion 15, but the contact surface between the terminal wire receiving portion and the wire conductor extends to the circumferential side surface of the wire conductor. Therefore, when rotating, the rotational force is transmitted through the circumferential side surface of the electric wire conductor, the electric wire conductor is in a state of being cut out, and the element wire is easily broken.
[0008]
As described above, when an attempt is made to connect an electric wire and a terminal using the conventional friction welding, particularly in the case of a low-rigidity and twisted structure W / H electric wire, a conductor is required at the time of butt joint because of low rigidity. Is buckled, and the conductor is broken during rotation due to the problem of the stranded wire structure. For this reason, if the conventional friction welding is applied as it is, there is a problem that the conductor is easily damaged and electrical and mechanical reliability of the connecting portion cannot be secured.
[0009]
Therefore, an object of the present invention is to provide a method of connecting a wire conductor and a terminal by a friction welding method, which is particularly suitable for a W / H wire having a low rigidity and a stranded wire structure.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 fixes an electric wire in a state where a conductor end surface is exposed, and press-contacts a joining surface of a terminal connected to a conductor of the electric wire with the end surface. The terminal is rotated in such a state that desired frictional heat is secured, and then the terminal is stopped to join an end face of the conductor and a joining surface of the terminal.
[0011]
According to the method of connecting a wire conductor and a terminal by friction welding according to the first aspect, since the conductor is fixed, the rigidity of the conductor can be improved. Therefore, the conductor does not buckle even if a butt pressure is applied to the conductor during friction welding. In addition, since the connection portion is limited to the conductor end surface, the rotating force applied during friction welding does not transmit through the conductor side surface, so that even if the terminal is rotated, the conductor may be broken. There is no.
[0012]
The invention described in claim 2 is characterized in that the end surface of the conductor and the joint surface of the terminal are further pressed at a timing when the terminal stops or before or after the terminal stops.
[0013]
According to the method of connecting a wire conductor and a terminal by the friction welding method according to the second aspect, the upset pressurization (the process of further pressurizing the joint of the connection portion at the timing of stopping or before or after the terminal) Is added, the joining force between the wire conductor and the terminal can be increased, efficient friction welding can be performed, and the product yield can be improved.
[0014]
The invention described in claim 3 is characterized in that a rib extending on a side surface of the conductor is provided on a joint surface of the terminal, and the end surface of the conductor is covered with the rib.
[0015]
According to the method for connecting a wire conductor and a terminal by the friction welding method according to the third aspect, a rib corresponding to the shape of the conductor end surface (a cylindrical shape in a W / H stranded wire or the like) is formed on the terminal joining surface side. By restricting the end face of the conductor with ribs, it is possible to increase the rigidity of the end part by reinforcing the end part of the conductor, and to avoid the situation where the wires are separated at the end face of the conductor during rotation, and to improve efficiency Good friction welding can be performed.
[0016]
According to a fourth aspect of the present invention, there is provided an electric wire fixing portion for fixing the electric wire and the conductor in a chucked state with the end face of the conductor exposed, and opposed to a joint surface of the terminal of the electric wire fixing portion. The opposite surface is provided with a melt adhesion protection member, and a portion of the wire fixing portion that contacts the side surface of the conductor is made of a conductive material.
[0017]
According to the method for connecting an electric wire conductor and a terminal by the friction welding method according to claim 4, the electric wire fixing portion for chucking and fixing the electric wire and the conductor is melted at the time of friction welding on the opposing surface facing the conductor end surface. A melt adhesion protection member is provided for protection from objects. In addition, by forming a portion of the wire fixing portion that contacts the side surface of the wire conductor with a conductive member, heat accumulated in the wire conductor can be diffused to the outside. For this reason, surface oxidation, thermal deformation, and the like of the conductor strand can be prevented, and the heat accumulated in the conductor is transmitted to the wire coating and does not melt the wire coating. Further, when preheating of the conductor is required before the friction welding, the conductor can be heated via the conductive member.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram for explaining a method of connecting a wire conductor and a terminal. In FIG. 1A, reference numeral 1 denotes an electric wire such as a stranded wire for W / H, 2 denotes a conductor that peels and exposes an insulating coating of the electric wire 1, 3 denotes a terminal to be connected to the conductor 2, and 4 denotes a joint of the terminal 3. The rib 5 formed so as to cover the conductor end face is a wire fixing jig (fixing portion) for fixing and holding the wire 1 and the conductor 2.
[0019]
The electric wire fixing jig 5 chucks the electric wire 1 so that the joint portion of the end of the conductor 2 of the electric wire 1 is slightly exposed. , And a body portion that comes into contact with the side surface of the conductor 2 is formed of a conductive member 8 such as aluminum or copper.
[0020]
Reference numeral 6 denotes a terminal fixing / rotating portion for fixing and rotating the terminal 3, and positions and fixes the terminal 3 on a pedestal or the like so that the rib 4 of the joining portion accurately faces the end face of the conductor 2. The terminal fixing / rotating section 6 advances so as to apply a load to the joint surface with the conductor 2 (X direction in the figure), and rotates to generate frictional heat after contact and pressurization with the end of the conductor 2 ( (Y direction indicated by an arrow in the figure). The driving force for advancing / rotating the terminal fixing / rotating unit 6 is supplied by, for example, a servomotor (not shown) of the spindle in the case of the rotational drive, and is controlled synchronously with the spindle in the case of the forward drive. The rotation of a servo motor (not shown) of the shaft is reduced by a ball screw, a speed reduction mechanism, or the like, and the rotation is converted into a linear movement and supplied.
[0021]
Further, the electric wire 1 and the conductor 2 will be described with reference to FIG. The electric wire 1 exposes the conductor 2 from the electric wire 1 by stripping the insulating coating covering the conductor 2. The electric wire fixing jig 5 holds the electric wire 1 and the exposed conductor 2, and holds the electric wire holding portion 2 b except for the joint portion 2 a at the distal end portion, and sets the joint portion 2 a so as to be slightly exposed from the electric wire fixing jig 5. And fix it by chucking.
[0022]
Looking at the relationship between the conductor 2 of the electric wire 1 and the terminal 3, as shown in FIG. 1B, the end face 2 a of the conductor 2 and the rib 4 formed at the joint 3 a of the terminal 3 face each other. Is fixed using a positioning sensor or the like.
[0023]
The electric wire 1 is chucked and fixed to the electric wire fixing jig 5 as described above, and the terminal 3 is fixed to the terminal / fixed rotating portion 6 and, in a state where they are opposed to each other (FIG. 1 (a)), the pressure contact connection is started. I do. First, the terminal fixing / rotating portion 6 is driven in the forward direction so that the end surface 2a of the conductor 2 and the rib 4 surface of the terminal 3 are completely brought into contact with each other, and further driven using a pressure sensor or the like to apply a predetermined load. I do. After applying a predetermined load, the terminal 3 is rotated at a predetermined speed. By bringing the joining surface 2a of the conductor 2 and the rib 4 into contact with each other under pressure and rotating, the frictional heat is generated only on the joining surface 2a. When the frictional heat reaches a predetermined temperature and the joining surface begins to melt, the motor of the rotating shaft is stopped. The pressurization is further increased at the same time as the rotation is stopped or at the timing before or after the rotation is stopped (upset pressurization), and the joining at the joining portion 2a is completed. Thereby, the electric wire 1 and the terminal 3 can be joined only by the joint 2a of the conductor 2 (FIG. 3).
[0024]
In a state where the electric wire 1 and the terminal 3 are joined, since a part of the conductor 2 is exposed, a covering process for covering (covering) the exposed portion of the conductor 2 is performed. As the coating process, as shown in FIG. 4, the exposed portion of the conductive wire 2 is fixed by molding with a resin 9 or the like, and then completely covered with the metal tube 10. As a result, the rigidity of the conductor is increased, and the conductor is sealed and protected from the outside, thereby preventing breakage, oxidation deterioration, and the like.
[0025]
【The invention's effect】
According to the first aspect of the present invention, the wire conductor is fixed in a state where the end face of the wire conductor is exposed, and the terminal is rotated in a state where the end face and the joining surface of the terminal are brought into pressurized contact with each other to obtain a desired frictional heat. After securing the terminal, the terminal was stopped and the end face of the wire conductor and the joining surface of the terminal were welded and joined, so the rigidity of the conductor could be improved by fixing the conductor, and the butt pressure was applied Even in this case, buckling of the conductor can be prevented. In addition, since the connection is made by friction welding, the reliability of the connection can be improved without requiring an interface protection treatment. Furthermore, unlike the crimping connection and the caulking connection, the structure of the connection portion is not accompanied by a structural deformation, so that the structure of the connection portion can be simplified and miniaturized.
[0026]
According to the second aspect of the present invention, the end surface of the conductor and the joining surface of the terminal are further pressed and pressed against each other at the timing when the terminal is stopped or before or after the terminal is stopped. The joining force can be increased, friction welding can be performed efficiently, and the product yield can be improved.
[0027]
According to the third aspect of the present invention, a rib extending on the side surface of the conductor is provided on the joint surface of the terminal, and the end surface is covered with the rib to prevent the end surfaces of the plurality of wire conductors from coming apart. In the case of handling a stranded wire for W / H, the stranded wire end face can be efficiently welded and joined to the terminal joining surface without dispersing.
[0028]
According to the invention of claim 4, a fixing portion for fixing the wire and the conductor in a chucked state is provided, and the surface of the fixing portion facing the joining surface of the terminal is provided with a melt adhesion protection member to prevent the adhesion of the melt. Since it has been prevented, it is possible to remove the mechanical and electrical adverse effects due to the molten deposits. In addition, a conductive member is provided at a portion in contact with the side surface of the conductor of the fixed portion so as to enhance heat diffusion during welding and heat conduction when extra heat before welding is required. It is possible to effectively act only on the joint surface without accumulating in the portion, and it is also possible to perform preheating by supplying heat from the outside.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram for explaining a connection method of the present invention.
FIG. 2 is a view showing an arrangement state of electric wires and terminals shown in FIG. 1;
FIG. 3 is a view showing a joined state of the electric wire and the terminal shown in FIG. 1;
FIG. 4 is a view showing a state where an exposed portion of the electric wire conductor shown in FIG. 3 is covered.
FIG. 5 is a view showing a conventional pressure welding connection between an electric wire and a terminal.
FIG. 6 is a view showing a conventional caulked connection between an electric wire and a terminal.
FIG. 7 is a diagram showing a conventional friction welding connection.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electric wire 2 Conductor 3 Terminal 4 Rib 5 Wire fixing part (jig)
6 Terminal fixing / rotating part 7 Melt adhesion protection member 8 Conductive member 9 Mold resin 10 Metal cylinder

Claims (4)

The electric wire 1 is fixed in a state where the end face of the conductor 2 is exposed, and the terminal 3 is rotated in a state where the joining surface of the terminal 3 connected to the conductor 2 of the electric wire 1 and the end face are brought into pressure contact with each other. After the frictional heat is secured, the terminal 3 is stopped and the end face of the conductor 2 is joined to the joint surface of the terminal 3 by a friction welding method. The connection between the wire conductor and the terminal by the friction welding method according to claim 1, wherein the end surface of the conductor and the joint surface of the terminal are further pressed at a time when the terminal stops or before or after the terminal stops. Method. 3. The method according to claim 1, wherein a rib extending from a side surface of the conductor is provided on a joint surface of the terminal, and the end surface of the conductor is covered with the rib. An electric wire fixing portion for fixing the electric wire and the conductor in a chucked state with the end face of the conductor exposed is provided, and a fusion adhesion protection member is provided on an opposing surface of the electric wire fixing portion opposite to the joining surface of the terminal. The method according to any one of claims 1 to 3, wherein a portion of the wire fixing portion that contacts the side surface of the conductor is made of a conductive material. .

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