JP2001015242A - Connecting method of insulating core wire to connector terminal by laser irradiation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce working man-hour, allow connecting work in a very narrow area, and enhance connecting reliability for a long time by converging laser beams with a convergent lens, melting a low melting point cover layer on the surface of a strand conductor for forming an insulating core wire and a low melting point cover layer on the surface of a connector terminal, and fusion- connecting the insulating core wire and the connector terminal. SOLUTION: A surface cover layer having a lower melting point than Cu of a conductor base material, for example tin plating, is formed on the surface of a strand conductor 4a, absorption and heat generation by laser beams 2 are generated in the tin plating layer, only the tin plating layer is melted, and a strand conductor 4c is formed. The surface layer part of a connector terminal 5 is formed with a solder plating layer using nickel as a primary coat, having lower melting point than brass for forming the connector terminal 5, therefore, absorption and heat generation by laser beams 2 are generated in the solder plating part, the connecting surface made of an alloy layer is formed on the interface with the strand conductor 4c, and the strand conductor 4a and the connector terminal 5 are connected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an insulated core wire and a connector.
Laser connection, especially CO2 ₂Leh
Melts the insulator of the small-diameter insulated core wire
Exposed and covered multiple conductor surfaces that make up the insulated core.
Insulating by fusing and unifying the covering layer
Melts the surface coating layer of core wires and connector terminals and connects them
Complete a series of tasks simultaneously and instantly
Non-contact connection method using laser beam and focusing lens
Regarding expressions.

[0002]

2. Description of the Related Art Conventionally, connection methods for connecting an insulated core wire and a connector terminal generally include crimping, pressure welding,
There are soldering methods and the like. First, in the crimping method, the insulation coating of the wire is peeled off in advance using a metal tool such as a stripper to expose the conductor portion, and then the crimping portion of the tubular structure having the insulation coating portion and the conductor exposed portion of the connector terminal. Then, using a suitable crimping tool, the cylindrical crimping portion is mechanically pressed and deformed in a lump including the insulating coating portion and the conductor exposed portion, and the electric wire and the connector terminal are connected. Next, in the pressure welding method, an insulating core wire is inserted into the U-shaped portion of the connector terminal having a U-shape and having a spring elasticity without peeling off the insulating coating of the electric wire. Is a method of connecting an insulated core wire and a connector terminal by using a plastic deformation force generated between the insulated core wire and a U-shaped portion. In the last soldering method, the molten alloy layer is formed by melting the solder by heat, and through this molten alloy layer, the insulation coating is peeled off and the conductor part of the insulated core wire and the pre-soldered conductor are connected to the connector terminal. This is a method of thermally connecting. Although there are various connection methods in this way, a series of pretreatment processes such as stripping the insulation coating of the wire by crimping and soldering and preliminary soldering by soldering before the connection between the wire and the connector terminal are necessary. Become.

[0003]

As a technical problem of each connection method, in the case of the crimping method, a special crimping tool is required for each conductor diameter of the electric wire and each shape of the connector terminal in order to press and deform the connector terminal. Processing becomes complicated,
The crimping method is not suitable for small-diameter electric wires whose mechanical strength is weaker than the connection theory, and the soldering method has a disadvantage that the work itself requires a high-level solder welding technique.

Further, in the crimping / soldering method, the insulation of the insulated core wire is required. However, since a metal tool such as a stripper is brought into direct contact with the insulated core wire and stripped, the internal conductor is easily damaged. Further, when the inner conductor is formed of a stranded wire, the conductor that has been twisted in advance at a constant pitch is likely to be separated by the peeling operation itself, and a series of operations such as a straightening operation for untwisting the conductor and a preliminary soldering are required. That is, each connection method requires a dedicated tool, and is divided before the connection between the electric wire and the connector terminal, and there is an unavoidable preprocessing, which has a disadvantage that the number of processing steps is increased.

On the other hand, as an environment surrounding the above-mentioned insulated core wires and connector terminals, in recent years, signal current flowing in or between electronic devices has become very small, and accompanying this, thinning of electric wires (AWG36-46 level). In addition, due to the tendency of the connector terminals to be finer, disconnection of the conductor is likely to occur, and this tendency has become more remarkable due to the increasing use of small-diameter electric wires.

That is, in the connection method between the insulated core wire and the connector terminal, particularly in the case of crimping and soldering, it is necessary to peel off the insulator of the insulated core wire before connection. The occurrence of wire breaks and the work itself that make up the conductor of the conductor are becoming extremely difficult.Moreover, when the conductor is a stranded wire, the twist of the conductor after peeling off at the time of peeling off the insulation coating increases more than before, There is a tendency for the number of processing steps to increase, such as the necessity of twisting the conductor again before the connection operation. In addition, in the case of the soldering method, there is a problem that a heat stress is applied to a peripheral portion of the connection due to heat of melting of the solder, and it is difficult to connect a small-diameter electric wire and a fine connector terminal in a small area. The pressure welding method increases the number of cases where the conductor strand is cut or damaged when the connector terminal is pressed into the U-shaped part due to the thinning of the wire, and the long-term connection reliability and reliability of the connection immediately after the pressure welding work are increased. There was a drawback of lacking in sex.

[0007]

According to the present invention, as a connection method for solving the problems, an insulated core wire 4 using a laser beam 2 which enables non-contact connection processing between the insulated core wire 4 and a connector terminal 5 is provided. Is melt-peeled, and the surface coating layers of the plurality of stranded conductors 4a forming the insulated core wire 4 are melted to form the stranded conductor 4c in which the stranded conductors 4a are integrated with each other, and This melt-integrated stranded conductor 4
by melting the surface coating layer of the c and the connector terminal 5, stranded conductor 4c and to form a molten alloy layer between the connector terminal 5, insulated wire 4 and the connector terminal 5 and the laser beam 2
Is converted into heat energy and connected.

As a method of converting light energy into heat energy, a laser beam 2 is focused in a spot shape by using a focusing lens 3 to increase the power density and an insulating coating 4 of an insulating core 4.
b, by irradiating the surface of the internally stranded conductor 4a and the connector terminal 5, the surface energy of each of these illuminated objects absorbs light energy, thereby converting into heat energy, thereby generating heat and melting. In addition, a series of behaviors occurring on these objects is irradiated with a laser beam 2.
Therefore, various pretreatments required in the related art become unnecessary, and the connection between the insulated core wire 4 and the connector terminal 5 becomes possible. Furthermore, since the laser beam 2 is focused by using the focusing lens 3, the connection operation in a small area becomes possible, and it can be used for the connection between the small-diameter insulated core wire 4 and the miniaturized connector terminal 5. Becomes Moreover, can be controlled by adjusting the amount removed lens focal distance and focus the irradiation area related to the combination and density of heat input irradiation power and the irradiation time, the connection between the small diameter insulated wires 4 and the connector terminal 5 Adaptive control becomes possible.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the present invention, the insulated wires 4, were used several annealed copper strands and (AWG # 36) insulated wires 4 which has been subjected to insulating coating 4b is subjected to low melting point tin plating on the surface of a conductor material. The connector terminal 5 is mainly composed of brass, has a nickel plating coating layer having a lower melting point than brass on the surface thereof, and has a solder plating coating layer having a lower melting point than brass on its outermost layer. Was used to verify the connection between the insulated core wire 4 and the connector terminal 5 by the laser light 2.

The laser beam 2 used was a CO ₂ laser whose irradiation was easy to control and the maintenance cost was low. Although an excimer laser can be used as a laser beam having a similar function, the system is expensive and the power
Although the energy is low and the insulation can be melt-peeled, the present invention is intended to peel off the insulation coating 4b, fuse and integrate the plurality of stranded conductors 4a, and melt-integrate the conductor 4c and the connector terminal 5. A CO ₂ laser, which is unsuitable for fusion splicing with, can be irradiated with high power and high energy.

The laser beam 2 is a pulsed laser beam whose irradiation energy can be easily controlled, but the irradiation energy is uniquely determined by the oscillation frequency, the duty ratio, and the number of irradiation pulses of the pulsed laser beam 2. The irradiation energy received by the insulated core wire 4 and the connector terminal 5 per unit area is determined by the focal point distance and defocusing of the focusing lens 3 for focusing the laser beam 2 described above.

As shown in FIG. 1A, the connection between the insulated core wire 4 and the connector terminal 5 is made by placing the connector terminal 5 to be connected on a smooth work and setting the insulated core wire 4 thereon. At this time, the work position is set to a point where the laser beam 2 is focused, and is set to a position where the irradiated laser beam 2 is efficiently absorbed.

[0013]

In this embodiment, the laser beam 2 is used as a parameter for determining the irradiation energy of the laser beam 2 described above.
The oscillation frequency, the duty ratio, the number of irradiation pulses, and the focal length of the focusing lens 3 are combined in a matrix, and the insulated core wire 4 and the connector terminal 5 are connected under a plurality of irradiation conditions. Observing the presence or absence of wire breakage at the fused integrated portion 4c of the stranded conductor 4a having the conductor portion exposed by melting and peeling off the insulating coating 4b, the insulating core wire 4 by the laser beam 2 and the focusing lens 3 and the connector terminal The optimum conditions for connection processing with No. 5 were verified. Table 1 shows the optimum irradiation conditions.

[0014]

[Table 1]

In Table 1, the focus position of the focusing lens indicates a state where the laser beam 2 is irradiated and the laser beam 2 is narrowed down by the focusing lens 3 to the coating layer of the connector terminal 5, in this embodiment, the surface plating layer. Result of the verification, the connection between between insulated wires 4 and the connector terminal 5 in the optimal irradiation conditions in Table 1 are secured 100%, the connection between the insulated wires 4 and the connector terminal 5 by the laser beam 2 and the focusing lens 3 Reliability has been proven. Table 1
Out the optimum irradiation conditions are, the melting of the insulating coating portion 4b of the insulated wire 4 in the region of insufficient irradiation energy, evaporation, and molten integration of stranded conductor 4a is due to insufficient, insulated wires 4 and connector It does not lead to connection with terminal 5.
If the irradiation energy is excessive, the stranded wire conductor 4a
Damage was confirmed, and it was found that the irradiation conditions could not be optimized.

In FIGS. 1 and 2, when the laser beam 2 focused by the focusing lens 3 is applied to the insulating coating portion 4b of the insulated core wire 4, most of the laser beam 2 is reflected on the surface of the object to be irradiated. Absorption of laser light 2 on the surface of the insulator by the specific absorption rate determined by the material of the insulating coating material,
An exothermic effect occurs. Further, when the pulsed laser beam 2 specified under the optimum irradiation conditions in Table 1 is continuously irradiated, heat generation in the insulating coating 4b is promoted, and finally, the insulating coating 4b melts and evaporates. This series of heat generation, melting, and evaporation phenomenon
Generated immediately after the irradiation of the laser beam 2, the insulating coating 4b evaporates,
The inner stranded conductor 4a is peeled off and comes to be exposed.

As for the behavior on the surface of the stranded conductor 4a, most of the irradiated laser beam 2 is reflected on the conductor surface, similarly to the behavior on the insulating coating 4b because the composition is made of metal. The laser beam 2 is absorbed in the vicinity of the conductor surface layer by a specific absorptance determined by the type of metal forming the laser beam. Since the conductor surface is coated with a surface coating layer having a lower melting point than Cu of the conductor material, in this example, tin plating,
Absorption and heat generation by the laser beam 2 first occur in the tin plating layer. In this state, when the pulsed laser beam 2 is repeatedly irradiated within the optimum irradiation conditions shown in Table 1, the tin plating layer on the conductor surface reaches the melting point due to instantaneous heat generation and melting starts. This molten layer enhances the laser absorptivity and also has a synergistic effect on promoting the heating of the entire conductor. On the other hand, in this temperature range, since the melting point of Cu inside the conductor is not reached, only the tin plating layer forming the surface layer of the plurality of stranded conductors 4a is melted without adversely affecting the internal conductor, A molten layer is formed between the plurality of stranded conductors 4a to form a stranded conductor 4c in which the plurality of stranded conductors are integrated as shown in FIG.

On the other hand, the surface of the connector terminal 5 is also irradiated with the laser beam 2 focused by the focusing lens 3. However, since the material is metal like the stranded conductor 4a, the surface of the connector terminal 5 has a laser beam. The light 2 absorbs and generates heat. In this case, since the surface layer of the connector terminal 5 is made of nickel as a base and has a melting point of a solder plating layer having a melting point lower than that of brass forming the connector terminal 5, absorption and heat generation by the laser beam 2 are generated in this solder plating layer. Occurs and melting begins. As a result, a molten alloy layer is formed on the boundary surface between the molten layer formed on the surface of the connector terminal 5 and the stranded conductor 4c that has been melted and integrated. In this state, when the irradiation of the pulsed laser beam 2 necessary for connection is stopped, as shown in FIG. 1 (c), the molten alloy layer shifts from the molten state to the cooled / solidified state, and the interface is formed of the alloy layer. A connection surface is formed to connect the stranded conductor 4a and the connector terminal 5. These series of actions occur instantaneously as in the melting and evaporation of the insulating coating 4b, and the connection is completed. It is confirmed that the stranded conductor 4a in this state is reliably connected to the connector terminal 5 in the connected state (presence or absence of conduction), and that there is no breakage or damage to the stranded wire of the stranded conductor 4c fused and integrated by irradiation. The optimum conditions in Table 1 were obtained. In this embodiment, the case where the surface coating layer of the stranded wire conductor and the surface coating layer of the connector terminal are plated is described. However, a solder dip or a solder paste may be used for the coating layer.

Although the case where the insulated core wire of the present invention is a stranded wire and is a typical connector terminal has been described as a representative example, other flat cables, coaxial cables, optical fiber core wires, connector terminals of other shapes, and odd-shaped connector terminals may be used. This method can be applied because the connection mechanism does not change even for a special case.
As described above, it goes without saying that various modifications are included in the design within the scope of the present invention.

[0020]

According to the connection method of the present invention, which uses a CO ₂ laser, focuses light energy into a minute spot by the focusing lens 3 and irradiates the object to be irradiated with concentrated light, (1) ) A metal layer having a low melting point is provided on the conductor surface of the electric wire (insulated core wire) requiring connection and the surface of the connector terminal.
_{Since the two} lasers are melted by continuous irradiation and connected to each other, pre-processing such as insulation peeling and preliminary soldering required in the related art becomes unnecessary, and the number of processing steps can be reduced. (2) Laser light irradiation can be concentrated on a very small area by the focusing lens, and the irradiation time is extremely short. Therefore, it is possible to minimize the thermal influence on the periphery of the connection part, and it is possible to miniaturize the insulation core wire. Processing within a small area, such as connection with a connector terminal, can be performed. (3) Unlike the prior art, at the time of connection, processing can be performed without contacting the insulated core wire and the connector terminal, so that connection can be made without damaging them, and connection reliability is dramatically improved. (4) Despite the superior connection method compared to the prior art, the connection can be easily made because a CO ₂ laser whose maintenance is easy is used. Its industrial value is great.

[Brief description of the drawings]

FIG. 1A is a perspective view of a typical embodiment, showing a state in which a laser beam 2 is irradiated to an insulated core wire 4 and a connector terminal 5 of the present invention. (B) After irradiating the insulating core wire 4 and the connector terminal 5 of the present invention with the laser beam 2, the insulating coating 4b melts and evaporates, and the surface of the internally stranded conductor 4a melts.
It is a perspective view in the state where the stranded wire conductors 4a were fused and integrated. (C) shows the insulated core wire 4 and the connector terminal 5 of the present invention.
FIG. 3 is a perspective view showing a state where the laser beam 2 is irradiated to the laser beam to complete connection.

FIG. 2 is a perspective view of an insulated core wire 4 before applying a laser beam 2 by applying an insulating coating 4b to a plurality of stranded conductors 4a of the present invention.

DESCRIPTION OF THE SYMBOLS 1. Connection method of insulated core wire and connector terminal by laser irradiation of the present invention 2 Laser light 3 Focusing lens 4 Insulated core wire 4a Twisted wire conductor 4b Insulating coating 4c Melted and integrated stranded wire conductor 4d Connector terminal -Integrated stranded wire conductor connected to the 5 connector terminal

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hideharu Kajizuka 2-12-8 Shimoodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Oki Electric Cable Co., Ltd. (72) Inventor Hiroyuki Kumehara 1-1-13, Shijukucho, Ashikaga-shi, Tochigi No. 8 (72) Inventor Teruhiko Hoshino 1-7-1, Higashi 1-chome, Kiryu-shi, Gunma (72) Inventor Toshihiro Inomata 2-35, Higashi-Kukata-cho, Kiryu-shi, Gunma White Corp 1-101 F-term (reference) 5E051 LA03 LB03

Claims (2)

[Claims] In a connection between an insulated core wire and a connector terminal, a laser beam is focused on the insulated core wire and the connector terminal by a converging lens, so that an insulating coating portion is melted and peeled to expose a conductor portion of the insulated core wire. A coating layer made of a material having a lower melting point than the stranded wire conductor on the surface of the stranded wire conductor that forms the insulated core wire, and the connector terminal on the surface of the connector terminal arranged along the insulated core wire. A method for connecting an insulated core wire and a connector terminal by laser irradiation, comprising: fusing a coating layer provided with a material having a low melting point; and fusing and connecting the insulated core wire and the connector terminal. 2. A method according to claim 1, wherein a CO ₂ laser is used as a laser beam.