JPH097647A - Wire connecting method - Google Patents

Abstract

PURPOSE: To provide a wire connecting method in which the contact resistance can be easily reduced without reducing the mechanical strength. CONSTITUTION: A coating 3 in the end part of a wire 4 formed of a conductor 2 consisting of a plurality of collected element wires 1 and the coating 3 applied thereto is peeled to form a part 6 to be crimped where the conductor 2 is exposed, and each element wire 1 is connected on the tip side of the part 6 to be crimped, whereby a connected part 7 and a non-connected part 8 are formed on the tip side and base end side, respectively, and a crimp terminal 10 is crimped to the non-connected part 8 of the part 6 to be crimped. Thus, since the collected form of the non-connected part 8 is easily deformed by the crimping of the crimp terminal 10, the contact surface between the connector 2 and the crimp terminal 10 is increased, and the contact resistance can be suppressed low. Further, since the element wire 1 which is not in direct contact with the crimp terminal 10 in the non-connected part 8 can be continued, in the connected part 7 adjacent to the non-connected part 8, to the element wire 1 being in direct contact with the crimp terminal 10 in the connecting part 8, the contact resistance between the wire 4 and the crimp terminal 10 can be suppressed low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric wire connecting method for crimping a crimped portion of an electric wire composed of a plurality of wires with a crimp terminal.

[0002]

2. Description of the Related Art In recent years, the performance of automobiles and general industrial equipment has been improved, which is considered to be the result of the application of various sensors. Along with this, the number of signal circuits for passing minute voltages and currents has increased, and the processing capability of the CPU for processing the information of these signal circuits to control the system has also improved.

However, when the number of parts handling such minute voltages and currents increases, the contact resistance and instantaneous interruption of the connection parts of electric wires and the like, which have not been a problem in the related art, have come to a great extent.

On the other hand, in the conventional method of mechanically crimping a crimp terminal to a crimped portion of an electric wire composed of a plurality of strands,
When the wires or crimp terminals are thermally expanded and contracted and deformed due to environmental temperature changes, good contact cannot be obtained between the wires or between the wires and crimp terminals, and the contact resistance between the crimp terminals and wires increases. There was a problem.

Therefore, in place of the above-mentioned conventional mechanical crimping, ultrasonic welding method and resistance welding method have begun to be used, and tin-plated electric wires have come to be used in the conventional mechanical crimping.

[0006]

However, in the case of welding, the tear strength is lower than that of mechanical crimping, so that
It is necessary to devise a method for protecting the welded portion, and further, when the electric wire is thin, there is a problem that the damage during welding is large and the mechanical strength of the welded portion is reduced. In addition, in the case of ultrasonic welding, the crimping terminals come into contact with the processing jig to cause wear due to ultrasonic vibration, and in the case of resistance welding, the crimping terminals come into contact with the electrodes to prevent oxidation and melting damage due to heat generation. May occur. In particular, when the crimp terminals are plated, there is a problem in that the underlying metal is exposed and the appearance is impaired, and that electrolytic corrosion occurs due to the exposure of dissimilar metals.

On the other hand, the tin-plated electric wire has good contact reliability because a new metal surface of tin appears due to plastic deformation during crimping and a gas-tight structure is obtained. Has a length of several mm to 1 cm only, but the whole electric wire has to be tin-plated due to the plating process, and there is a problem that the material waste is very large.

A method of applying a conductive paste prepared by dissolving a powder of a noble metal, copper, carbon or the like in an organic resin to an electric wire and crimping the same has been proposed. In this case, however, the contact resistance increases when the resin hardens or Since gas is released due to evaporation of the resin or decomposition of the resin in a high temperature environment, the released gas reacts with the components in the ambient atmosphere and adheres to the pressure-bonded portion, forming a film and increasing the contact resistance. However, there is a problem that the resin of the connector housing may be melted or damaged depending on the type of the organic substance.

Therefore, the present invention has been made in order to solve the above problems, and provides a wire connecting method which can easily reduce the contact resistance without lowering the mechanical strength. With the goal.

[0010]

In order to solve the above-mentioned problems, the electric wire connecting method according to the first aspect is such that the covering of the end portion of the electric wire is formed by covering the conductor in which a plurality of strands are assembled. To form a pressure-bonded portion in which the conductor is exposed, and to bond the individual wires of the pressure-bonded portion only in a predetermined region to each other so that the wires are bonded to each other And a crimp terminal is crimped to the non-joined portion of the crimped portion.

Further, as described in claim 2, the respective wires of the joint portion may be joined by ultrasonic welding, resistance welding, laser welding or soldering.

[0012]

When the crimp terminal is crimped to the non-joint portion where the wires are in a disjointed state as in the wire connecting method according to claim 1 or 2, the wires are joined to each other. Since the aggregate shape of each wire is easily deformed compared to the joint part, the joint strength between the wire and the crimp terminal is increased, and the contact area between the non-joint part and the crimp terminal is increased, which leads to The contact resistance between the and crimp terminals can be kept low.
In addition, the wire that cannot directly contact the crimp terminal at the non-bonding portion can be electrically connected to the wire that directly contacts the crimp terminal at the bonded portion at the bonding portion adjacent to the non-bonding portion.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, a crimped portion 6 made of the conductor 2 exposed by peeling off the coating 3 at the end of an electric wire 4 obtained by applying a coating 3 to a conductor 2 in which a plurality of strands 1 are assembled.
To form Then, only the tip side of the crimped portion 6 is joined to each other by resistance welding, ultrasonic welding, laser welding, or soldering to join the strands 1 to the tip side of the crimped portion 6. The joined portion 7 is formed, and the non-joined portion 8 where the wires 1 are not joined to each other is formed on the base end side. At this time, when welding is performed by resistance welding, ultrasonic welding, or laser welding, it is preferable to perform welding while applying a certain amount of pressure so that the wires 1 are well assembled.

After processing the crimped portion 6 of the electric wire 4 in this manner, as shown in FIG. 2, the crimp portion 11 formed on one end of the crimp terminal 10 is unbonded by a crimping machine (not shown). 8 is crimped in a holding shape to connect the electric wire 4 and the crimp terminal 10.

When the electric wire 4 and the crimp terminal 10 are connected by the above method, the crimp terminal 10 is crimped to the non-joint portion 8 in which the individual wires 1 of the portion to be crimped 6 are disjointed. The aggregate shape of each strand 1 of the joint 8 is easily deformed,
While improving the joint strength between the electric wire 4 and the crimp terminal 10,
The contact area between the non-bonded portion 8 and the crimp terminal 10 increases,
The contact resistance with the crimp terminal 10 can be kept low. In addition, even if there is a wire 1 that cannot be directly contacted with the crimp terminal 10 in the non-bonding portion 8, the wire 1 is bonded to the non-bonding portion 8 at the bonding portion 7 adjacent to the non-bonding portion 8. Since electrical continuity is obtained with the element wire 1 that is in direct contact with the wire 10, the contact resistance between the wire 4 and the crimp terminal 10 can be kept low. Further, when the crimp terminal 10 is connected to the electric wire 4, the crimp portion 11 of the crimp terminal 10 is only bent and compressed by a crimping machine.
As in the case of ultrasonic welding or resistance welding, the crimping terminal 10 is not damaged by abrasion due to vibration caused by the contact of the processing jig with the crimping terminal 10, oxidation by heat generation, and melting loss, and the crimping terminal 10 is also damaged. Does not happen. Further, since the pressure is applied mechanically, the bonding strength is also strong. Further, since it is not necessary to perform the plating treatment on the wire 1, and only the predetermined region of the pressure-bonded portion 6 needs to be bonded, the material is not wasted. Furthermore, since no organic resin or the like is used, problems such as increase in contact resistance and gas release due to changes in the ambient temperature environment do not occur.

By the way, after the crimped portion exposed at the end of the electric wire made of 50 annealed copper wires having a wire diameter of 0.18 mm is joined only in a predetermined region to form a joined portion and a non-joined portion,
A crimp terminal made of brass is crimped to the non-bonded portion to perform a thermal shock durability test, and the initial contact resistance value before the start of the test,
The contact resistance value after endurance was measured by repeating the thermal shock for 400 cycles of -40 to 120 ° C for 30 minutes each, and the results were as shown in Fig. 3. For comparison, FIG. 3 shows the same data as in the case of the conventional crimping method in which a crimp terminal is mechanically crimped to an electric wire made of an unplated wire and an electric wire in which the wire is tin-plated. Similar data is also shown when mechanical crimping of the crimp terminal is performed.

As can be seen from the above, when the parts to be crimped are joined and then crimped, the initial resistance value becomes lower than that of the conventional method, and the same initial resistance value as when crimping the tin-plated wire is obtained. It can be seen that the change in the initial resistance value and the resistance value after the endurance are small as well as when the tin-plated electric wire is crimped, and the stability in the endurance test is improved.

Even when a plurality of electric wires are connected to each other by crimping terminals, as shown in FIG. 4, each crimped portion 6a exposed at the end of each electric wire 4a is formed in the same manner as in the above embodiment. The individual wires are joined to each other only on the tip end side to form the joining portion 7a on the tip end side and the non-joining portion 8a on the base end side, and the non-joining portion 8a is formed by bundling the crimped portions 6a.
Alternatively, the crimp terminal 10a may be crimped. Also in this case, the contact resistance between the respective electric wires 4a and the crimp terminals 10a becomes low as in the above embodiment, and as a result, the contact resistance between the respective electric wires 4a can be kept low.

Further, as shown in FIG. 5, depending on the position and shape of the crimp portion of the crimp terminal, for example, when the crimp portion is near the middle of the crimp terminal, the crimped portion 6b at the end of the electric wire 4b is pressed.
The wires 1b on the base end side are joined to each other to form the non-joint portion 8b on the tip side of the crimped portion 6b and the joint portion 7b on the base end side, or the crimp portion of the crimp terminal is crimped. When two terminals are formed on one end side of the terminal with a predetermined interval, the element wires on the base end side and the tip end side of the portion to be crimped are joined to form a joint portion depending on the position. At the same time, the bonded portion may be formed in the middle thereof.

[0020]

As described above, according to the electric wire connecting method of the first or second aspect of the present invention, not the joining portion where the individual wires of the crimped portion are joined, but the non-joining of the individual wires is in a disjointed state. Since the crimp terminal is crimped to the part, the aggregate shape of the individual wires of the non-bonded part can be easily deformed, increasing the bonding strength between the wire and the crimp terminal, and making contact between the non-bonded part and the crimp terminal. Since the area is increased, the contact resistance between the electric wire and the crimp terminal can be suppressed to be low. In addition, the wire that cannot be directly contacted with the crimp terminal at the joined part should be electrically connected to the wire that is directly contacted with the crimped terminal at the joined part at the joining part adjacent to the non-joined part. Therefore, the contact resistance between the electric wire and the crimp terminal can be kept low.

[Brief description of drawings]

FIG. 1 is a side view showing an intermediate step of an embodiment according to the present invention.

FIG. 2 is a perspective view of another process of one embodiment.

FIG. 3 is a diagram showing a measurement result of contact resistance in one example.

FIG. 4 is a perspective view showing another embodiment.

FIG. 5 is a side view showing still another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Elementary wire 2 Conductor 3 Coating 4 Electric wire 6 Crimped part 7 Joined part 8 Joined part 10 Crimp terminal

Claims (2)

[Claims] 1. A conductor to which a plurality of strands are assembled is coated to peel off a coating on an end of an electric wire to form a crimped portion in which the conductor is exposed. After forming a joined portion where the wires are joined and a non-joined portion where the joining is not made by joining only in a predetermined region, crimp terminals are crimped to the non-joined portion of the crimped portion. Wire connection method characterized by. 2. The electric wire connecting method according to claim 1, wherein the individual wires of the joint are joined by ultrasonic welding, resistance welding, laser welding or soldering.