JP2014099385A - Electric wire with terminal and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric wire with a terminal of which the connection reliability between the terminal and the electric wire is enhanced and a method for manufacturing the same.SOLUTION: An electric wire 10 with a terminal comprises: an electric wire 11 having a conductor 12 made of copper or copper alloy and an insulation coating 13 which covers the conductor 12; and a terminal 20 having a connection part 24 to which an exposed conductor 12 exposed in a terminal 11A of the electric wire 11. The terminal 20 is made of stainless steel, and the connection part 24 is formed by crimping a cylindrical part 23 which is provided at the terminal 20 and into which the exposed conductor 12 can be inserted while performing resistance heating at a state that the exposed conductor 12 is inserted into the cylindrical part 23.

Description

  The present invention relates to an electric wire with a terminal and a method for manufacturing the same.

As an electric wire with a terminal provided with a conductor consisting of a stranded wire obtained by twisting a plurality of metal strands with an insulating coating, and an electric wire where the conductor is exposed at the terminal and a terminal connected to the terminal of the electric wire For example, the thing of patent document 1 etc. are known.
In the electric wire with a terminal described in Patent Document 1, a wire barrel of a terminal is crimped to an exposed conductor exposed at the end of the electric wire so as to be electrically connected.

Japanese Utility Model Publication No. 5-72053

  Although the terminal of the electric wire with a terminal given in the above-mentioned patent documents 1 is a product made from a copper alloy, materials other than a copper alloy are considered as a material of a terminal in consideration of a place etc. where an electric wire is wired.

  Here, when an electric wire with a terminal in which a terminal made of a stainless material is connected by crimping to an exposed conductor of an electric wire having a copper conductor, the resistance value between the conductor and the electric wire increases in an environment with a large temperature difference. There was a problem that electrical connectivity deteriorated.

  This invention is completed based on the above situations, Comprising: It aims at providing the electric wire with a terminal which improved the connection reliability of a terminal and an electric wire, and its manufacturing method.

  The resistance value increases due to the difference in thermal expansion coefficient between the conductor and the electric wire due to the difference in thermal expansion coefficient when the terminal-attached electric wire connected by crimping to the exposed conductor of the electric wire with a copper conductor is connected to the stainless steel terminal. It may be possible to move the contact point with or decrease the number of contact points.

  As a result of diligent studies to solve this problem, it was found that the increase in resistance value can be suppressed even when the terminal is placed in an environment with a large temperature difference by connecting the terminal to the exposed conductor of the electric wire by crimping while performing resistance heating. It was.

  That is, the present invention has a terminal having a wire having a conductor made of copper or a copper alloy and an insulating coating covering the conductor, and a terminal having a connection portion to which an exposed conductor exposed at the end of the wire is connected. An electric wire, wherein the terminal is made of stainless steel, and the connecting portion is crimped while resistance heating a cylindrical portion provided in the terminal and through which the exposed conductor is inserted, in a state in which the exposed conductor is inserted. It is an electric wire with a terminal formed by doing.

  Further, the present invention includes a terminal having a wire having a conductor made of copper or a copper alloy and an insulating coating covering the conductor, and a terminal having a connection portion to which an exposed conductor exposed at the end of the wire is connected. A method of manufacturing an electric wire, wherein the terminal is made of stainless steel, and the cylindrical portion is provided in the terminal and inserted through the exposed conductor, and then the cylindrical portion is resisted. It is a manufacturing method of the electric wire with a terminal characterized by forming the above-mentioned connecting part by carrying out pressure bonding while heating.

  In the present invention, the connection portion between the exposed conductor and the terminal is formed by pressure-bonding the cylindrical portion in which the exposed conductor is inserted while resistance heating. In the present invention, the strong oxide film formed on the surface of the stainless steel terminal before crimping is joined to the conductor (electric wire) in a state of being destroyed by resistance heating, so that the contact point to be electrically connected is This increases the connection reliability between the terminal and the electric wire. As a result, according to the present invention, it is possible to provide a terminal-attached electric wire with improved connection reliability between the terminal and the electric wire and a method for manufacturing the electric wire.

The present invention may have the following configurations.
The conductor may be plated with nickel. Such a configuration is preferable because the heat resistance of the electric wire (conductor) is improved.

You may form the said connection part by crimping the said cylindrical part, carrying out resistance heating using the crimping die of the shape along the cross-sectional shape of the said exposed conductor.
With such a configuration, the cylindrical body of the terminal is deformed into a shape along the cross-sectional shape of the exposed conductor and subjected to thermocompression bonding, so that a large force does not act on the crimping die and a method with excellent thermal efficiency. Since a connection part can be formed, it is preferable.

  ADVANTAGE OF THE INVENTION According to this invention, the electric wire with a terminal which improved the connection reliability of a terminal and an electric wire, and its manufacturing method can be provided.

The perspective view of the electric wire with a terminal of Embodiment 1 Side view of electric wire with terminal Explanatory drawing explaining the procedure of inserting an electric wire into a terminal Perspective view of the terminal (before crimping) with the wire inserted The perspective view which shows the procedure which arrange | positions the terminal of FIG. 4 to a crimping | compression-bonding metal mold | die. Side view in the state of FIG. The perspective view which shows a mode that the terminal of FIG. 4 was pinched | interposed into the crimping die. Side view in the state of FIG. Front view of a crimping die described in another embodiment

<Embodiment 1>
The electric wire 10 with a terminal of Embodiment 1 of this invention is demonstrated with reference to FIG.
The electric wire 10 with a terminal of Embodiment 1 consists of the electric wire 11 and the terminal 20 connected to the terminal 11A of the electric wire 11, as shown in FIG. In the following description, the vertical direction will be described with reference to FIG. 2, and the front-back direction will be described with the left side of FIG. 2 as the front and the right side as the rear.

  As shown in FIG. 1, the conductor 11 is covered with a synthetic resin insulating coating 13 around the conductor 12. At the terminal 11A of the electric wire 11, as shown in FIG. 3, the insulating coating 13 is stripped and the conductor 12 is exposed (corresponding to “exposed conductor 12”).

  The conductor 12 is a stranded wire in which many (plural) metal strands are twisted together. The conductor 12 (metal strand) is made of copper or a copper alloy. In the present embodiment, the conductor 12 is plated with nickel. The electric wire 11 has a substantially circular cross section.

  The terminal 20 includes a flat terminal connection portion 21 connected to a mating terminal (not shown), and a cylindrical wire connection portion 24 (connection portion) connected to the rear of the terminal connection portion 21 and connected to the electric wire 11. Example). A terminal connection hole 22 for connecting a counterpart terminal is provided in a substantially central portion of the terminal connection portion 21.

  The conductor 12 of the electric wire 11 is inserted through the cylindrical portion 23. In the present embodiment, the cylindrical portion 23 is formed by deforming a portion that continues to the rear from the flat terminal connection portion 21 into a cylindrical shape.

  A substantially central portion in the longitudinal direction of the cylindrical portion 23 is compressed more than other portions as shown in FIG. Although the cylindrical part 23 is in contact with the conductor 12 in the entire region, the contact area with the conductor 12 is particularly large in the compressed part 24 in the substantially central part. The compressed portion 24 corresponds to the wire connecting portion 24. The wire connection portion 24 has a cross-sectional area of 80% to 95% with respect to the cross-sectional area of the portion 25 corresponding to the wire connection portion 24 before compression (the cross-sectional area cut in the direction orthogonal to the longitudinal direction). It is compressed and has a substantially circular shape.

  The terminal 20 is made of stainless steel. Examples of the stainless steel composing the terminal 20 include austenite such as SUS304, ferrite such as SUS430, martensitic stainless such as SUS410, and the like.

Next, the manufacturing method of the electric wire 10 with a terminal of this embodiment is demonstrated.
A terminal 20 having the shape shown in FIG. 3 is prepared, and the insulating coating 13 of the terminal 11A of the electric wire 11 is peeled off to expose the conductor 12. Next, as shown in FIG. 4, the conductor 12 (exposed conductor 12) exposed at the terminal 11 </ b> A of the electric wire 11 is inserted into the cylindrical portion 23 of the terminal 20.

  The cylindrical portion 23 of the terminal 20 into which the exposed conductor 12 of the electric wire 11 is inserted is crimped while being resistance-heated using a crimping die 30 shown in FIGS. At the time of thermocompression bonding, the cylindrical portion 23 of the terminal 20 is sandwiched between a crimping mold 32 disposed on the lower side and a crimping mold 31 disposed on the upper side (see FIGS. 7 and 7). 8).

  In the present embodiment, since the crimping die 30 having a shape along the cross-sectional shape of the exposed conductor 12 is used as the crimping die 30, the exposed conductor 12 is disposed along the current-carrying portion 33 of the crimping die 30 (FIG. 7). And see FIG. After the state shown in FIG. 7, current is passed through the energizing portion 33 of the crimping die 30 to compress the cylindrical portion 23 while resistance heating.

  By crimping the cylindrical portion 23 of the terminal 20 into which the exposed conductor 12 of the electric wire 11 is inserted while resistance heating, a part of the cylindrical portion 23 of the terminal 20 is compressed to form a substantially circular electric wire connecting portion 24. The electric wire 10 with a terminal shown in FIG. 1 is obtained.

Next, the effect of this embodiment will be described.
In the present embodiment, the wire connecting portion 24 between the exposed conductor 12 and the terminal 20 is formed by pressure-bonding the cylindrical portion 23 in which the exposed conductor 12 is inserted while resistance heating. The strong oxide film formed on the surface of the manufactured terminal 20 is joined to the electric wire 11 in a state of being broken by resistance heating. As a result, according to the present embodiment, the number of contacts at which the terminal 20 and the electric wire 11 (conductor 12) are electrically connected is increased, and the connection reliability between the terminal 20 and the electric wire 11 is improved. The terminal-attached electric wire 10 with improved connection reliability between the electric wire 11 and the electric wire 11 and the manufacturing method thereof can be provided.

  Moreover, according to this embodiment, since the conductor 12 is nickel-plated, the heat resistance of the electric wire 11 (conductor 12) improves.

  Further, according to the present embodiment, the wire connecting portion 24 is formed by crimping the cylindrical portion 23 while resistance heating using the crimping die 30 having a shape along the cross-sectional shape of the exposed conductor 12. Since the cylindrical portion 23 of the terminal 20 is deformed and thermocompression-bonded into a shape along the cross-sectional shape of the exposed conductor 12, a large force does not act on the crimping die 30, and the wire connection portion is formed by a method with excellent thermal efficiency 24 can be formed.

<Example>
Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1
An electric wire with a terminal was manufactured by the following method using a terminal having a shape shown in FIG. 3 manufactured using SUS430 as a terminal, using an electric wire having a conductor of annealed copper stranded wire 3sq.

The insulation coating on the end of the electric wire was peeled to expose the conductor, and the exposed conductor was inserted into the cylindrical portion of the terminal. Next, using the crimping die shown in FIG. 5, crimping was performed while resistance heating, and the terminal and the exposed conductor of the wire were connected to obtain the terminal-attached wire of Example 1. Three electric wires with terminals were prepared. In resistance heating, a current of 5 kA was passed through the crimping die and energized for 300 ms. The compression rate of the electric wire connection part was 93%.
The compression rate was calculated by the following formula.
Compressibility (%) = (Cross sectional area of wire connecting part after crimping / Cross sectional area of wire connecting part before crimping) × 100

(Comparative Example 1)
Instead of using the crimping die shown in FIG. 5 for resistance heating, crimping the cylindrical portion of the terminal to the exposed conductor of the wire without heating using a crimping die with a hexagonal cross section of wire connection A terminal-attached electric wire of Comparative Example 1 was produced in the same manner as in Example 1 except that. Three electric wires with terminals were produced in the same manner as in Example 1. The compression rate of the electric wire connection part was 81%.

(Evaluation Test 1)
A cooling cycle test was performed on three electric wires with terminals of Example 1 and three electric wires with terminals of Comparative Example 1. About each electric wire with a terminal, the resistance value before a thermal cycle test (initial resistance value) and the resistance value after a thermal cycle test (resistance value after a heat test) were measured.

  In the thermal cycle test, a thermal shock of −40 ° C. to 150 ° C. was applied to the electric wires with terminals for 240 cycles using a thermal shock tester (TSA-201S manufactured by ESPEC).

  The measurement results of the initial resistance value and the resistance value after the heat test are shown in Table 1. In Table 1, “Initial” means “Initial resistance value (mΩ)”, “After durability” means “Resistance value after heat test (mΩ)”, and “Average value” means an electric wire with three terminals The average resistance value (mΩ) is shown.

(Results and discussion)
As shown in Table 1, in the electric wire with a terminal of Example 1 that was crimped while resistance heating, the result that the resistance value after the durability test was significantly lower than the electric wire with a terminal of Comparative Example 1 was obtained.

  From this result, the resistance value of the terminal-attached electric wire provided with the electric wire connecting portion formed by crimping the cylindrical portion of the terminal through which the exposed conductor is inserted with resistance heating hardly increases even after the cold cycle test. I understood that.

  In addition, as shown in Table 1, the resistance value after the thermal cycle test was large in the electric wire with terminal of Comparative Example 1, but the resistance value was almost non-uniform in the electric wire with terminal of Example 1. was gotten.

  From this result, in the electric wire with a terminal provided with the electric wire connection portion formed by crimping while resistance heating the cylindrical portion of the terminal through which the exposed conductor is inserted, the effect of not increasing the resistance value after undergoing the thermal cycle. It was found that it can be obtained stably.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, the terminal-attached electric wire 10 including the electric wire connecting portion 24 having a circular cross section produced using the crimping die shown in FIG. 7 is shown. However, the connection having a hexagonal cross section as shown in FIG. The electric wire with a terminal formed with the crimping | die crimping die 40 in which a part is formed may be sufficient. The crimping die 40 shown in FIG. 9 includes an upper crimping die 41 and a lower crimping die 42 as in the crimping die 30 shown in FIG. The cross-sectional shape of the electric wire crimped while resistance heating using this crimping die 30 is hexagonal.

  (2) In the above embodiment, the copper conductor 12 plated with nickel is shown as the conductor 12. However, the conductor may be tin-plated or not plated. Good.

DESCRIPTION OF SYMBOLS 10 ... Electric wire with a terminal 11 ... Electric wire 11A ... Terminal 12 ... Conductor 13 ... Insulation coating 20 ... Terminal 21 ... Terminal connection part 23 ... Cylindrical part 24 ... Electric wire connection part (connection part)
25: Portion corresponding to the connection part before compression 30, 40 ... Crimping die 31, 41 ... Upper crimping die 32, 42 ... Lower crimping die 33, 43 ... Current-carrying part

Claims (4)

An electric wire with a terminal including a conductor having a conductor made of copper or a copper alloy and an insulating coating covering the conductor, and a terminal having a connection portion to which an exposed conductor exposed at an end of the electric wire is connected,
The terminal is made of stainless steel,
The connecting portion is a terminal-attached electric wire formed by crimping a tubular portion provided in the terminal, through which the exposed conductor is inserted, with resistance heating in a state where the exposed conductor is inserted. The electric wire with a terminal according to claim 1, wherein the conductor is nickel-plated. A method of manufacturing an electric wire with a terminal provided with an electric wire having a conductor made of copper or a copper alloy and an insulating coating covering the conductor, and a terminal having a connection portion to which an exposed conductor exposed at an end of the electric wire is connected. And
The terminal is made of stainless steel,
After inserting the exposed conductor into a cylindrical portion provided in the terminal and through which the exposed conductor is inserted,
The method of manufacturing an electric wire with a terminal, wherein the connecting portion is formed by pressure-bonding the cylindrical portion while resistance heating. The manufacturing method of the electric wire with a terminal of Claim 3 which forms the said connection part by crimping the said cylindrical part, resistance heating using the crimping die of the shape along the cross-sectional shape of the said exposed conductor.

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