JP2015109168A - Covered wire with terminal and wire harness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated wire with a terminal in which an electric connection part between a wire conductor and a terminal metal fitting on a surface of which a metal layer containing tin is formed is coated by an anticorrosive agent, in which spreading of corrosion generated in a portion of a terminal metal fitting, which is not coated with the anticorrosive agent, to the electric connection part and the wire conductor is suppressed, and such a wire harness.SOLUTION: In a coated wire with a terminal, a wire conductor of the coated wire and a terminal metal fitting 5 are electrically connected in an electric connection part, and the electric connection part is coated by an anticorrosive agent 7 made of insulating resin. A copper-tin alloy layer 56 is formed on a surface of at least a portion of the terminal metal fitting 5 coated by the anticorrosive agent 7 in the exposed manner on a layer under the anticorrosive agent 7.

Description

  The present invention relates to a coated electric wire with a terminal and a wire harness, and more particularly relates to a coated electric wire with a terminal excellent in corrosion resistance of an electric connection portion between an electric wire conductor and a terminal fitting, and a wire harness using the same.

  A terminal fitting is connected to the wire conductor at the end of the covered wire that is routed in a vehicle such as an automobile. It is required to prevent corrosion in the electrical connection portion where the terminal fitting and the wire conductor of the covered wire are electrically connected.

  In recent years, the use of aluminum or aluminum alloy as a material for electric wire conductors has been studied for the purpose of reducing the weight of vehicles such as automobiles. On the other hand, copper or a copper alloy is often used as a material for the terminal fitting. Further, the surface of the terminal fitting is often subjected to plating such as tin plating. In other words, the wire conductor and the terminal fitting may be made of different materials. If the wire conductor and the terminal fitting are made of different materials, corrosion due to contact with different metals occurs at the electrical connection portion. For this reason, it is calculated | required that an electrical connection part should carry out corrosion prevention reliably. Therefore, in order to prevent corrosion of the electrical connection portion, for example, in Patent Document 1, an electrical connection portion between a wire conductor made of aluminum or an aluminum alloy and a terminal fitting made of copper or a copper alloy is formed by an anticorrosive agent made of an adhesive resin. Covering is described.

JP 2011-103266 A

  By covering the electrical connection portion between the wire conductor and the terminal fitting with the anticorrosive agent, the occurrence of corrosion in the electrical connection portion can be highly suppressed. However, although a tin plating layer is generally formed on the surface of the terminal fitting, tin has a relatively low oxidation-reduction potential among various metal species and is susceptible to corrosion. If rust occurs at the part of the terminal fitting that is not covered with the anticorrosive agent and the tin plating layer is exposed, the rust is generated along the surface of the terminal fitting and reaches the electrical connection part. May reach up to. Then, there exists a possibility that the electrical property and the mechanical characteristic may deteriorate in the electrical connection part and the electric wire conductor.

  The problem to be solved by the present invention is a coated electric wire with a terminal in which an electrical connection portion between a wire conductor and a terminal metal fitting on which a metal layer containing tin is formed is coated with an anticorrosive agent. An object of the present invention is to provide a coated electric wire with a terminal in which corrosion generated in a portion not covered with an anticorrosive agent is suppressed from reaching the electrical connection portion and the electric wire conductor, and such a wire harness.

  In order to solve the above-described problems, the coated electric wire with a terminal according to the present invention is such that the wire conductor of the coated electric wire and the terminal fitting are electrically connected at the electric connection portion, and the electric connection portion is made of an insulating resin. The gist is that a copper tin alloy layer is exposed on the lower layer of the anticorrosive agent on the surface of at least the portion of the terminal fitting covered with the anticorrosive agent.

  The covered electric wire with a terminal according to claim 1, wherein the electric wire conductor has a strand made of aluminum or an aluminum alloy, and the terminal fitting is made of copper or a copper alloy as a base material.

  The wire harness concerning this invention makes it a summary to have said covered electric wire with a terminal.

  According to the coated electric wire with a terminal according to the present invention, the electrical connection portion between the terminal fitting and the wire conductor is coated with the anticorrosive agent, and the corrosion of the electrical connection portion due to the direct exposure of the electrical connection portion to the corrosive environment. Is prevented. In addition, a layer made of a copper-tin alloy that has a higher oxidation-reduction potential than tin and is less susceptible to corrosion is formed on the surface of at least a portion of the terminal fitting that is covered with the anticorrosive. Thereby, even if corrosion occurs on the surface of the portion other than the electrical connection portion that is not covered with the anticorrosive agent in the terminal fitting, the electrical connection portion covered with the anticorrosive agent and the electrical connection portion are continuous. Corrosion is less likely to progress in the wire conductor.

  Here, when the wire conductor has a strand made of aluminum or an aluminum alloy and the terminal fitting is made of copper or a copper alloy as a base material, a dissimilar metal is in contact with the electrical connection portion of the coated electric wire with a terminal. If the anti-corrosion treatment is not applied, the probability of corrosion will increase, but the corrosion of the dissimilar metals due to direct contact of the electrical connection with moisture etc. is possible because this electrical connection is covered with the anti-corrosion agent. What happens is highly avoided. In addition, a structure in which a copper tin alloy layer is laminated can be easily formed by creating a tin layer on the surface of the terminal fitting by using copper or a copper alloy as a base material and appropriately heating the terminal fitting. Can do.

  Since the wire harness according to the present invention has the above-described coated electric wire with a terminal, high anticorrosion performance is obtained at the electrical connection portion between the terminal fitting and the wire conductor, and is not covered with the anticorrosive agent of the terminal fitting. Corrosion generated on the surface is prevented from reaching the electrical connection.

It is an external appearance perspective view of an example of the covered electric wire with a terminal of the present invention. FIG. 2 is a longitudinal sectional view taken along line AA in FIG. 1. It is a schematic diagram which shows the cross section of a terminal metal fitting.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Outline of covered electric wire with terminal)
FIG. 1 is an external perspective view showing an example of a coated electric wire with a terminal according to the present invention, and FIG. 2 is a longitudinal sectional view taken along line AA in FIG. As shown in FIG. 1 and FIG. 2, the covered electric wire 1 with a terminal of the present invention is such that the electric wire conductor 3 of the covered electric wire 2 in which the electric wire conductor 3 is covered with the insulator 4 and the terminal fitting 5 are electrically connected at the electric connection portion 6. It is connected to the.

  The terminal fitting 5 includes a tab-like connection portion 51 made of an elongated flat plate connected to a counterpart terminal, a wire barrel 52 extending at the end of the connection portion 51, and an electric wire fixing portion made of an insulation barrel 53. 54.

  In the electrical connection portion 6, the insulator 4 at the end of the covered electric wire 2 is peeled off to expose the electric wire conductor 3, and the exposed electric wire conductor 3 is crimped to one side of the terminal metal fitting 5. And the terminal fitting 5 are connected. The wire barrel 52 of the terminal fitting 5 is crimped from above the wire conductor 3 of the covered electric wire 2 so that the wire conductor 3 and the terminal fitting 5 are electrically connected. Further, the insulation barrel 53 of the terminal fitting 5 is crimped from above the insulator 4 of the covered electric wire 2.

  And the electric connection part 6 is coat | covered with the anticorrosive 7 in the range shown with the dashed-dotted line in FIG. 1 is shown in a state where the anticorrosive 7 is seen through. The anticorrosive 7 prevents the metal portion from corroding due to the entry of moisture or the like into the wire conductor 3, the contact portion between the wire conductor 3 and the terminal fitting 5 from the outside.

  The specific part which the anticorrosive 7 has coat | covered is the following parts. As shown in FIG. 1, the tip 2 a side of the covered electric wire 2 is covered with an anticorrosive 7 so as to protrude slightly from the tip of the wire conductor 3 to the connection portion 51 side of the terminal fitting 5. The tip 5 a side of the terminal fitting 5 is covered with the anticorrosive 7 so as to slightly protrude from the end of the insulation barrel 53 to the insulator 4 side of the covered electric wire 2. As shown in FIG. 2, the side surface 5 b of the terminal fitting 5 is also covered with the anticorrosive agent 7. The back surface 5 c of the terminal fitting 5 is not covered with the anticorrosive 7. In this way, the electrical connection portion 6 is covered with the anticorrosive agent 7 with a predetermined thickness along the outer peripheral shape of the terminal fitting 5 and the covered electric wire 2. The portion where the end of the covered wire 2 is peeled off and the wire conductor 3 is exposed is completely covered with the anticorrosive 7 and is not exposed to the outside. If the electrical connection is not affected, the back side of the wire fixing portion 54 of the terminal fitting 5 (including the back side of the wire barrel 52 and the insulation barrel 53) may be covered with the anticorrosive 7. .

  Accordingly, three of the peripheral ends of the anticorrosive agent 7 that covers the electrical connection portion 6 are in contact with the surface of the terminal fitting 5, and one is in contact with the surface of the insulator 4. That is, most of the peripheral edge of the anticorrosive 7 is in contact with the surface of the terminal fitting 5.

Hereinafter, the material which comprises each part of the covered electric wire 1 with a terminal is demonstrated.
(Coated wire)
The electric wire conductor 3 of the covered electric wire 2 is made of a stranded wire formed by twisting a plurality of strands 3a. In this case, the stranded wire may be composed of one type of metal strand or may be composed of two or more types of metal strand. Moreover, the twisted wire may contain the strand etc. which consist of organic fibers other than a metal strand. Note that “consisting of one type of metal strand” means that all the metal strands constituting the stranded wire are made of the same metal material, and “consisting of two or more types of metal strands” This means that the wire contains metal wires made of different metal materials. The stranded wire may include a reinforcing wire (tension member) for reinforcing the covered electric wire.

  Examples of the material of the metal wire constituting the wire conductor 3 include copper, a copper alloy, aluminum, an aluminum alloy, or a material obtained by applying various platings to these materials. Examples of the material of the metal strand as the reinforcing wire include copper alloy, titanium, tungsten, and stainless steel. Examples of the organic fiber as the reinforcing wire include Kevlar.

  Examples of the material of the insulator 4 include rubber, polyolefin, PVC, and thermoplastic elastomer. These may be used alone or in combination of two or more. Various additives may be appropriately added to the material of the insulator 4. Examples of the additive include a flame retardant, a filler, a colorant and the like.

(Terminal bracket)
In FIG. 3, the structure of the material which comprises the terminal metal fitting 5 is shown as sectional drawing. Examples of the base material 55 constituting the terminal fitting 5 include various copper alloys, copper, and the like in addition to brass that is generally used. A copper tin alloy layer 56 is formed on the surface of the base material 55 at least in a portion of the terminal metal 5 covered with the anticorrosive agent 7, and the surface of the copper tin alloy layer 56 is covered with the anticorrosive agent 7.

  A tin layer is formed on the surface of the base material 55 made of copper or a copper alloy by electrolytic plating or the like, and appropriately heated to form a copper tin alloy layer 56 by alloying between the tin layer and the copper of the base material 55 can do. If heating is performed for a long time, finally, the entire tin layer formed first can be made into the copper tin alloy layer 56 as shown in FIG. As a heating temperature at the time of alloying, the range of 150-200 degreeC can be illustrated. If a heating temperature within this range is selected, alloying can proceed effectively, and the copper tin alloy layer 56 with high thickness uniformity can be formed.

  The surface of the terminal fitting 5 other than the portion covered with the anticorrosive 7 is covered with a different metal layer even if it is covered with the copper tin alloy layer 56 in the same manner as the portion covered with the anticorrosive 7. But you can. From the viewpoint of simplicity of manufacturing the terminal fitting 5, the copper tin alloy layer 56 is uniformly formed on the entire surface of the terminal fitting 5 over the portion coated with the anticorrosive 7 and the portion not covered. Is preferred.

(Anticorrosive)
The anticorrosive 7 is made of an insulating resin whose main component is an adhesive resin. Any adhesive resin may be used as long as it is a resin that can adhere to the metal surface. In particular, if the coating is applied in a state with high fluidity and can be changed to a state with low fluidity after coating, a layer of the anticorrosive agent 7 with high adhesion is easily formed at a site including the electrical connection portion 6. be able to. Examples of such resins include thermoplastic resins and various curable resins. Examples of the curable resin include an ultraviolet curable resin, a thermosetting resin, a moisture curable resin, and a two-component reaction curable resin. Examples of the resin type include acrylic resin, epoxy resin, polyamide resin, urethane resin, silicone resin, and polyolefin resin. These may be used alone or in combination of two or more. In addition, additives such as coloring pigments, viscosity modifiers, anti-aging agents, inorganic fillers, storage stabilizers, and dispersants may be added to the anticorrosive agent 7.

  In order to form the layer of the anticorrosive 7 in the region including the electrical connection portion 6 of the coated electric wire 1 with a terminal, as described above, after applying the anticorrosive 7 in a highly fluid state to a predetermined site, A state with low fluidity may be used. Specifically, in the case where the anticorrosive agent 7 includes a thermoplastic resin, the anticorrosive agent 7 that is heated to be liquid may be applied to a predetermined portion and then allowed to cool. In the case where the anticorrosive agent 7 contains various curable resins, it may be cured by a curing method corresponding to each resin after being applied in a liquid state to a predetermined site. In other words, UV irradiation is applied to UV-curable resins, heating is applied to thermosetting resins, humidification is applied to moisture-curable resins, and two-component reaction-curable resins are mixed for two hours. Good. For applying the liquid anticorrosive 7, known means such as a dropping method, a coating method, and an extrusion method can be used. Moreover, in order to improve the permeability (coating property) of the anticorrosive agent 7, the anticorrosive agent 7 may be diluted with a solvent when applied.

(Anti-corrosion at electrical connection)
Since different kinds of metals are in contact with the electrical connection portion 6, corrosion of the metal is liable to occur when moisture enters. However, since the region including the electrical connection portion 6 is covered with the close corrosion inhibitor 7, moisture does not easily enter the electrical connection portion 6, and the electrical connection portion 6 is in direct contact with moisture. Corrosion is prevented from occurring. In particular, when the electric wire conductor 3 is made of aluminum or an aluminum alloy, a copper tin alloy layer 56 having a higher oxidation-reduction potential than pure tin is formed on the surface of the terminal fitting 5 constituting the electrical connection portion 6, and oxidized. Since it contacts the wire conductor 3 made of aluminum or aluminum alloy having a low reduction potential, the wire conductor 3 is likely to be corroded when contacted with moisture. The occurrence of corrosive corrosion can also be suppressed to a high degree.

  On the other hand, the metal is directly exposed on the surface of the terminal metal fitting 5 that is not covered with the anticorrosive agent 7, and such a portion is easily corroded by contact with moisture. When corrosion occurs in a portion not covered with the anticorrosive 7 and a tin layer that is susceptible to corrosion is exposed in the lower layer of the anticorrosive 7, it is adjacent along the surface of the terminal fitting 5. Corrosion may proceed to the surface of the portion covered with the anticorrosive agent 7, and the corrosion may reach the electric wire conductor 3. However, in the coated electric wire 1 with a terminal, the copper tin alloy layer 56 is formed at least on the surface of the portion covered with the anticorrosive agent 7. As described above, the copper tin alloy layer 56 has a higher oxidation-reduction potential than tin and is not easily corroded. Therefore, even if corrosion occurs in a portion of the terminal fitting 5 that is not covered with the anticorrosive 7, The rate at which the corrosion proceeds along the surface of the terminal metal fitting 5 toward the wire conductor 3 side through the portion coated with the anticorrosive 7 is slower than when only the tin layer is formed on the surface. Become. Thereby, it is suppressed that the corrosion which generate | occur | produced in the site | part which is not covered with the anticorrosive 7 of the terminal metal fitting 5 progresses in the electrical connection part 6 covered with the anticorrosive 7.

  In this way, the corrosion of the electrical connection portion 5 that can proceed in two paths is suppressed by the effects of the presence of the anticorrosive 7 and the presence of the copper-tin alloy layer 56. Thereby, even if it exposes to the corrosive environment, the electrical property and mechanical property in the electrical connection part 6 and the electric wire conductor 3 continuing to it are maintained.

(Wire Harness)
The wire harness concerning this invention consists of a some covered electric wire containing the covered electric wire 1 with a terminal concerning the said invention. All of the covered electric wires constituting the wire harness may be the covered electric wires with terminals 1 according to the present invention, or only a part thereof may be the covered electric wires 1 with terminals according to the present invention.

  Examples of the present invention and comparative examples are shown below. In addition, this invention is not limited by these Examples.

1. Preparation of covered electric wire For 100 parts by mass of polyvinyl chloride (degree of polymerization 1300), 40 parts by mass of diisononyl phthalate as a plasticizer, 20 parts by mass of calcium bicarbonate as a filler, 5 parts by mass of calcium zinc-based stabilizer as a stabilizer A polyvinyl chloride composition was prepared by mixing at 180 ° C. with an open roll and molding into pellets with a pelletizer.

  Next, using a 50 mm extruder, the polyvinyl chloride composition obtained above was 0.28 mm thick around a conductor (cross-sectional area 0.75 mm) made of an aluminum alloy twisted wire in which seven aluminum alloy wires were twisted together. And extrusion coated. This produced the covered electric wire (PVC electric wire).

2. Production of terminal metal fittings A tin layer was formed on the entire surface of a male crimp terminal metal fitting made of brass (tab width 0.64 mm), which is widely used for automobiles. About the terminal metal fitting of Example 1, it annealed at 170 degreeC then, the whole tin layer was alloyed with copper of a base material, and the copper tin alloy layer was formed. It was confirmed by observing the cross section of the terminal fitting with a scanning electron microscope (SEM) that the entire tin layer was a copper tin alloy. On the other hand, the terminal fitting in which the tin layer not subjected to the annealing treatment was formed was used as the terminal fitting according to Comparative Example 1.

3. Production of covered electric wire with terminal After peeling off the terminal of the produced covered electric wire and exposing the electric wire conductor, each produced terminal fitting was crimped and crimped to the terminal of the covered electric wire. Next, an anticorrosive agent made of urethane adhesive ("Ultra SU" manufactured by Konishi Co., Ltd.) was applied to the electrical connection portion between the electric wire conductor and the terminal fitting, and it was allowed to rest at 25 ° C for 7 days to be cured. Thus, the covered electric wire with a terminal concerning Example 1 and Comparative Example 1 was obtained.

4). Evaluation method About each covered electric wire with a terminal, the salt spray test was done based on JISC0023, and anticorrosion performance was evaluated. That is, a 96-hour salt spray test was performed on the entire terminal fitting including the electrical connection portion. And after peeling off an anticorrosive and resin coating, the external appearance of the electric wire conductor of an electrical-connection part was determined visually. The case where corrosion did not occur (when rust was not generated) was evaluated as “good”, and the case where corrosion was generated (when rust was generated) was determined as “failed”. In any of the covered electric wires with terminals, corrosion was observed in a portion of the terminal fitting that was not covered with the anticorrosive agent.

<Results and discussion>
Table 1 shows the results of the salt spray test for the coated electric wires with terminals according to Example 1 and Comparative Example 1.

  According to Table 1, in the covered electric wire with terminal according to Example 1 in which the copper tin alloy layer was formed on the surface of the terminal fitting, no corrosion occurred on the electric wire conductor in the salt spray test. On the other hand, in the covered electric wire with a terminal according to Comparative Example 1 in which the tin layer was formed on the surface of the terminal fitting, corrosion was observed in the electric wire conductor in the salt spray test. This is because, by providing a copper tin alloy layer having a higher oxidation-reduction potential than tin on the surface of the terminal fitting, the corrosion generated in the portion not covered by the anticorrosive agent is electrically connected to the anticorrosive agent and This shows that it is possible to prevent the electric connection portion from reaching a continuous wire conductor.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Coated electric wire with terminal 2 Coated electric wire 3 Electric wire conductor 4 Insulator 5 Terminal metal fitting 52 Wire barrel 53 Insulation barrel 54 Electric wire fixing part 55 Base material 56 Copper tin alloy layer 6 Electrical connection part 7 Anticorrosive

Claims (3)

The wire conductor of the covered electric wire and the terminal fitting are electrically connected at the electric connection portion, and the electric connection portion is covered with an anticorrosive agent made of an insulating resin,
A coated electric wire with a terminal, wherein a copper tin alloy layer is exposed and formed in a lower layer of the anticorrosive agent on a surface of at least a portion of the terminal fitting covered with the anticorrosive agent.   The covered electric wire with a terminal according to claim 1, wherein the electric wire conductor has a strand made of aluminum or an aluminum alloy, and the terminal fitting is made of copper or a copper alloy as a base material.   A wire harness comprising the coated electric wire with a terminal according to claim 1.

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