JP2020087868A - Electric wire with terminal and method for manufacturing electric wire with terminal - Google Patents

Abstract

An object of the present invention is to provide an electric wire with a terminal that suppresses corrosion of a core wire of an aluminum electric wire and has excellent corrosion resistance, and a method for manufacturing the electric wire with a terminal. A barrel part (41) to be crimped to a core wire (11) is composed of a first layer (21c) containing copper or a copper alloy, a second layer (21d) containing tin, and a third layer (21e) containing tin from the far side of the core wire (11). and , in this stacking order. Also, the contact portion 31 connected to the mating terminal has a first layer 21c and a second layer 21d in this stacking order. The thickness of the second layer 21d is greater than the thickness b in the stacking direction of the copper-tin alloy region 21f formed by the tin contained in the second layer 21d and the copper contained in the first layer 21c. It is configured such that the thickness a in the direction is greater. Further, the thickness of the third layer 21e in the stacking direction is a thickness that prevents the second layer 21d from being exposed to the outside due to deformation of the third layer 21e when the barrel portion 41 is crimped to the core wire 11. FIG. [Selection drawing] Fig. 2

Description

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

2. Description of the Related Art In recent years, wire harnesses installed in vehicles have been crimp-connected with electric wires having a core wire made of aluminum or aluminum alloy (hereinafter referred to as "aluminum electric wires") and terminal fittings made of copper or copper alloy for weight reduction. Wires with terminals may be used. In this type of terminal-attached electric wire, water adhering between the core wire of the electric wire, which is made of a different metal, and the terminal fitting serves as an electrolytic solution, and galvanic corrosion (dissimilar metal contact corrosion) may occur. As is well known, galvanic corrosion is caused by the difference in standard electrode potential between different metals, and the greater the difference, the more likely galvanic corrosion occurs.

For example, in one of the conventional electric wires with terminals, a galvanic corrosion is suppressed by forming a plating layer or an insulating coating on the surface of the crimped portion of the terminal fitting to the electric wire (see, for example, Patent Document 1).

JP, 2012-094340, A

Examples of the plating layer provided on the terminal fitting in order to suppress galvanic corrosion between the core wire of the aluminum electric wire and the terminal fitting include a plating layer containing tin. The reason for this is that the difference in standard electrode potential between copper or copper alloy, which is a general material for terminal fittings, and aluminum or aluminum alloy (difference without plating), tin, which constitutes the plating layer, and aluminum. Alternatively, the difference in the standard electrode potential between the aluminum alloy and the aluminum alloy (difference with plating) is smaller. In other words, the latter (with plating) can suppress galvanic corrosion because the difference in standard electrode potential is smaller than the former (without plating).

The standard electrode potential is a parameter related to the ionization tendency (ease of corrosion) of the material, and the smaller the standard electrode potential, the greater the ionization tendency and the more likely it is to corrode. The standard electrode potential can be defined as, for example, an electromotive force in a standard state of a battery made by combining an electrode made of the material and a standard hydrogen electrode. For example, the standard electrode potential of aluminum is about −1.67V, the standard electrode potential of tin is about −0.14V, and the standard electrode potential of copper is about 0.52V. The standard electrode potential of an aluminum alloy depends on its composition, but is generally smaller than the standard electrode potentials of tin and copper described above. Similarly, the standard electrode potential of copper alloys, which depends on their composition, is generally greater than the standard electrode potentials of aluminum and aluminum alloys described above.

By the way, when a plating layer containing tin is provided on a terminal fitting, if a layer containing copper or a copper alloy (for example, a copper underlayer and a copper base material of the terminal fitting) is in contact with the plating layer, the copper Alternatively, a copper-tin alloy may be formed between the layer containing the copper alloy and the plated layer. Here, the standard electrode potential of the copper-tin alloy is generally higher than the standard electrode potential of tin (original plating layer), although it varies depending on its composition. In other words, the difference in the standard electrode potential between the copper-tin alloy and the core material of the aluminum wire (the copper-tin alloy is exposed) means that the standard electrode potential between the tin and the core material is different (the copper-tin alloy is not exposed). ) Greater than. Therefore, when the copper-tin alloy is exposed on the surface of the plating layer in this way, galvanic corrosion is more likely to occur than when it is not exposed. It is desirable that such corrosion be suppressed.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electric wire with a terminal and a method for manufacturing an electric wire with a terminal that suppress corrosion of a core wire of an aluminum electric wire and have excellent corrosion resistance. ..

In order to achieve the above-mentioned object, an electric wire with a terminal and a method for manufacturing an electric wire with a terminal according to the present invention are characterized by the following [1] to [4].
[1]
An electric wire with a terminal, comprising an electric wire having a core wire made of aluminum or an aluminum alloy, and a terminal fitting having a barrel portion crimped to the core wire and a contact portion connected to a mating terminal,
The barrel portion is
Having a first layer containing copper or a copper alloy, a second layer containing tin, and a third layer containing tin from the side distant from the core when being crimped to the core, in the order of lamination,
The contact portion is
When it is crimped to the core wire, from the side far from the core wire, the first layer and the second layer, in the order of lamination,
The second layer is
The core-side surface of the second layer and the surface of the first layer of the copper-tin alloy region formed by the tin contained in the second layer and the copper contained in the first layer in the laminating direction. It is configured such that the distance in the stacking direction between the surface on the core wire side is large,
The third layer is
The thickness of the third layer in the stacking direction is configured such that the second layer is not exposed to the outside due to deformation of the third layer when the barrel portion is pressure-bonded to the core wire. The
It must be an electric wire with a terminal.
[2]
In the electric wire with a terminal according to the above [1],
The thickness of the third layer is 3.0 μm or more and 7.0 μm or less,
It must be an electric wire with a terminal.
[3]
For manufacturing an electric wire with a terminal, which includes an electric wire having a core wire made of aluminum or an aluminum alloy, and a terminal fitting having a barrel portion crimped to the core wire and a contact portion connected to a mating terminal In the method of manufacturing an electric wire with a terminal,
The metal plate material has a first layer containing copper or a copper alloy and a second layer containing tin from the side distant from the core wire when the metal plate material is pressure-bonded to the core wire, so that the metal plate material has a second layer containing tin in this order of lamination. A step of treating the metal plate material,
Molding a primary molded body having a shape corresponding to the terminal fitting from the metal plate material;
Molding a portion of the primary molded body corresponding to the barrel portion so as to have a preliminary shape capable of receiving the core wire;
A step of molding a portion corresponding to the contact portion of the primary molded body so as to have the shape of the contact portion;
A portion corresponding to the barrel portion having the preliminary shape includes the first layer, the second layer, and a third layer containing tin from the side farther from the core wire when pressure-bonded to the core wire. A step of treating the portion corresponding to the barrel portion so as to have this stacking order;
Pressure-bonding the barrel portion having the first layer, the second layer, and the third layer to the core wire.
It must be a method of manufacturing electric wires with terminals.
[4]
In the method of manufacturing an electric wire with a terminal according to the above [3],
A treatment is applied to a portion corresponding to the barrel portion so that the thickness of the third layer is 3.0 μm or more and 7.0 μm or less,
It must be a method of manufacturing electric wires with terminals.

According to the electric wire with a terminal having the above configuration (1), the barrel portion crimped to the core wire made of aluminum or an aluminum alloy includes the first layer containing copper or a copper alloy and tin from the side far from the core wire. It has the 2nd layer containing and the 3rd layer containing tin in this lamination order. Furthermore, regarding the layer structure in the stacking direction, the thickness of the copper-tin alloy region formed by the tin contained in the second layer and the copper contained in the first layer in the stacking direction is larger than the thickness of the copper-tin alloy region in the stacking direction and the surface on the core wire side of the second layer. The second layer is configured such that the distance in the stacking direction between the one layer and the surface on the core wire side is large. Therefore, the copper tin alloy is not exposed on the surface of the second layer, and galvanic corrosion between the copper tin alloy and the core wire of the aluminum electric wire can be suppressed.

Furthermore, the third layer has a thickness in the stacking direction in which the second layer is not exposed to the outside due to deformation of the third layer when the barrel portion is pressure-bonded to the core wire. Therefore, for example, when the barrel portion is pressure-bonded to the core wire, even if the third layer comes into pressure contact with the pressure-bonding mold (for example, anvil and crimper), and the third layer is worn or crushed, The two layers are not exposed to the outside. In other words, the third layer can properly protect the second layer during the crimping process. Therefore, the above-described copper-tin alloy region is more appropriately prevented from being exposed to the outside.

Therefore, the electric wire with a terminal of the present configuration can appropriately suppress the corrosion of the core wire of the aluminum electric wire, as compared with the case where the second layer and the third layer do not have the above structure and the copper-tin alloy is exposed to the outside, Excellent in corrosion resistance.

According to the electric wire with a terminal having the above configuration (2), the thickness of the third layer is 3.0 μm or more and 7.0 μm or less. According to experiments and consideration conducted by the inventor, if the third layer has such a thickness, the second layer is exposed to the outside due to the deformation of the third layer when the barrel portion is crimped onto the core wire. It has become clear that they will not. Therefore, with this configuration, it is possible to reliably suppress corrosion of the core wire of the aluminum electric wire and provide an electric wire with a terminal having excellent corrosion resistance.

According to the method for manufacturing an electric wire with a terminal having the above configuration (3), the electric wire with a terminal manufactured is a barrel portion crimped to a core wire made of aluminum or an aluminum alloy, and is made of copper or copper from a side far from the core wire. It has a first layer containing a copper alloy, a second layer containing tin, and a third layer containing tin in this order of lamination. Furthermore, regarding the layer structure in the stacking direction, the thickness of the copper-tin alloy region formed by the tin contained in the second layer and the copper contained in the first layer in the stacking direction is less than the thickness of the second layer on the core wire side and the first layer. The second layer is configured such that the distance in the stacking direction between the one layer and the surface on the core wire side is large. Therefore, the copper-tin alloy is not exposed on the surface of the second layer, and galvanic corrosion between the copper-tin alloy and the core wire of the aluminum electric wire can be suppressed.

Further, according to the present manufacturing method, after molding the portion corresponding to the barrel portion of the primary molded body of the terminal fitting so as to have a predetermined preliminary shape, the third layer is formed at the portion corresponding to the barrel portion. It will be. Therefore, as compared with the case where the molding having the preliminary shape is not performed (the case where the third layer is directly molded on the primary molded body), the amount of deformation of the portion corresponding to the barrel portion during the subsequent crimping to the core wire is small, The third layer can be formed thicker.

Therefore, the third layer can be easily formed to a thickness such that the second layer is not exposed to the outside due to deformation of the third layer when the barrel portion is pressure-bonded to the core wire in the stacking direction. Therefore, for example, when the barrel portion is pressure-bonded to the core wire, even if the third layer comes into pressure contact with the pressure-bonding mold (for example, anvil and crimper), and the third layer is worn or crushed, The two layers are not exposed to the outside. In other words, the third layer can properly protect the second layer during the crimping process. Therefore, the above-described copper-tin alloy region is more appropriately prevented from being exposed to the outside.

Therefore, the method for manufacturing an electric wire with a terminal of this configuration can appropriately suppress the corrosion of the core wire of an aluminum electric wire, as compared with the case where the second layer and the third layer do not have the above-mentioned configuration and the copper-tin alloy is exposed to the outside. Therefore, it is possible to manufacture an electric wire with a terminal having excellent corrosion resistance.

According to the method for manufacturing an electric wire with a terminal having the above configuration (4), the thickness of the third layer of the electric wire with a terminal manufactured is 3.0 μm or more and 7.0 μm or less. According to experiments and consideration conducted by the inventor, if the third layer has such a thickness, the second layer is exposed to the outside due to the deformation of the third layer when the barrel portion is crimped onto the core wire. It has become clear that they will not. Therefore, according to the present manufacturing method, it is possible to reliably suppress the corrosion of the core wire of the aluminum electric wire and provide an electric wire with a terminal having excellent corrosion resistance.

ADVANTAGE OF THE INVENTION According to this invention, the corrosion of the core wire of an aluminum electric wire is suppressed, and the electric wire with a terminal excellent in corrosion resistance and the manufacturing method of the electric wire with a terminal can be provided.

The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through the modes for carrying out the invention described below (hereinafter referred to as “embodiments”) with reference to the accompanying drawings.

FIG. 1 is a perspective view of an electric wire with a terminal according to the present embodiment. FIG. 2 is a schematic view showing a state of surface treatment at a contact portion and a barrel portion of the terminal fitting, and FIG. 2(a) is a schematic view showing an arrangement of electric wires when crimping the terminal fitting to the electric wire, 2B is a sectional view taken along the line AA of the contact portion of FIG. 2A, and FIG. 2C is a sectional view taken along the line BB of the barrel portion of FIG. 2A. 2D is an enlarged view of a C portion in FIG. 2B, and FIG. 2E is an enlarged view of a D portion in FIG. 2C. FIG. 3 is an enlarged view of an F portion of FIG. 2E, and is a view for explaining a more detailed cross-sectional structure of the barrel portion of the terminal fitting. FIG. 4 is a flow chart showing each step of the method for manufacturing an electric wire with a terminal according to this embodiment, and a schematic diagram showing a cross-sectional structure of a contact portion and a barrel portion in each step.

<Embodiment>
Hereinafter, an example of an embodiment according to the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of an electric wire with a terminal 1 according to the present embodiment. FIG. 2 is a longitudinal sectional view of the electric wire 10 and the terminal fitting 20. In addition, in the following description, the left side in FIG. 1 is shown as “front” and the right side is shown as “rear”.

As shown in FIG. 1 and FIG. 2A, the terminal fitting 20 is crimped to the end of the electric wire 10 and the terminal fitting 20 and the core wire 11 of the electric wire 10 are electrically connected to each other. The electric wire with a terminal 1 including the metal fitting 20 is manufactured. The electric wire 1 with a terminal constitutes a wire harness to be installed in a vehicle such as an automobile.

The electric wire 10 is an insulated electric wire having a core wire 11 and a coating 12 made of a resin that covers the core wire 11. The core wire 11 is configured by twisting a plurality of element wires made of aluminum or aluminum alloy. By configuring the core wire 11 of the electric wire 10 from aluminum or an aluminum alloy, the weight of the terminal fitting 20 is reduced, and the weight of the wire harness including the terminal fitting 20 is also reduced. The lightweight terminal fitting 20 is particularly suitable for vehicles such as electric vehicles and hybrid vehicles in which wire harnesses are frequently used.

The terminal fitting 20 has a contact portion 31 to be connected to the counterpart terminal at the front portion, and a sheath crimp portion 41 crimped to the core wire 11 of the electric wire 10 and a sheath crimp crimped to the sheath 12 of the electric wire 10. It has a portion 42 at the rear. Hereinafter, the core wire crimping portion 41 is also referred to as a barrel portion 41 for convenience. The contact part 31 and the barrel part 41 are connected to each other by a connecting part 32.

The contact portion 31 is disposed on the front side of the barrel portion 41 and has a box-like shape corresponding to the shape of the mating terminal (not shown). As shown in the AA sectional view of FIG. 2B, the contact portion 31 has a substantially rectangular shape in a cross section orthogonal to the axis of the terminal fitting 20, and has a hollow portion inside. A mating terminal (not shown) is inserted into this hollow portion. A spring-like terminal 33 that comes into contact with a mating terminal (not shown) is provided in the hollow portion.

Further, as shown in the BB sectional view of FIG. 2C, the barrel portion 41 has a substantially U-shape in a cross section orthogonal to the axis of the terminal fitting 20. As shown by the arrow in FIG. 2A, after the core wire 11 exposed from the coating 12 at the end of the electric wire 10 is placed on the barrel bottom surface 43 of the barrel portion 41, the barrel portion 41 is The core wire 11 is crimped and electrically connected to the core wire 11. The cover crimp portion 42 is crimped to the outer surface of the cover 12 and fixed to the cover 12.

As shown as an enlarged view of a portion C in FIG. 2D, the contact portion 31 has a base material layer 21a of the terminal fitting 20, a nickel layer 21b, a copper underlayer (first layer) 21c, and a first portion. The tin-plated layer (second layer) 21d is laminated in this order. In other words, the base material layer 21a is subjected to a surface treatment in which the nickel layer 21b, the copper underlayer 21c, and the first tin plating layer 21d are laminated in this order. Details of this surface treatment will be described later. To put it the other way around, the contact part 31 has a copper underlayer 21c and a first tin-plated layer 21d in this order of lamination from the side far from the core wire 11 when crimp-connected to the core wire 11 of the electric wire 10. ing. Furthermore, the end surface E of the contact portion 31 is not covered with the above-mentioned layers and is exposed to the outside.

On the other hand, as shown as an enlarged view of a portion D in FIG. 2E, the barrel portion 41 has a base material layer 21a of the terminal fitting 20, a nickel layer 21b, a copper underlayer (first layer) 21c, A first tin plating layer (second layer) 21d and a second tin plating layer (third layer) 21e are laminated in this order. In other words, the base material layer 21a is subjected to a surface treatment in which the nickel layer 21b, the copper underlayer 21c, the first tin plating layer 21d, and the second tin plating layer 21e are laminated in this order. Details of this surface treatment will be described later. To put it the other way around, when the barrel portion 41 is crimp-connected to the core wire 11 of the electric wire 10, the copper base layer 21c, the first tin plating layer 21d, and the second tin plating layer 21e are arranged from the side far from the core wire 11, In the stacking order. Further, the end surface E of the barrel portion 41 is covered with the second tin plating layer 21e and is not exposed to the outside.

As shown in FIG. 3 as an enlarged view of the F portion, in this example, the copper-tin alloy region 21f of tin and copper is formed between the underlayer 21c and the first tin-plated layer 21d. It is generated so as to grow toward the inside of the layer 21d.

When the above-mentioned surface treatment is applied to the barrel portion 41, the surface of the first tin plating layer 21d closer to the core wire 11 and the base layer 21c than the thickness b of the copper-tin alloy region 21f in the stacking direction (vertical direction in FIG. 3) is determined. The thickness of the first tin-plated layer 21d is designed in advance so that the thickness a in the stacking direction between the surface on the core wire 11 side is larger (a>b). This design may be performed in consideration of the degree of growth of the copper-tin alloy region 21f specified based on a preliminary experiment or the like.

Further, the thickness c of the second tin plating layer 21e in the stacking direction is such that the first tin plating layer 21d is exposed to the outside due to deformation such as abrasion or crushing of the second tin plating layer 21e that occurs when the barrel portion 41 is caulked to the core wire 11. It is thick enough to ensure that it does not. For example, according to an experiment conducted by the inventor, the thickness of the second tin plating layer 21e is preferably 3.0 μm or more and 7.0 μm or less. The second tin-plated layer 21e is molded so that its surface is matte, and thus the appearance of the region where the second tin-plated layer 21e is provided and the region where the second tin-plated layer 21e is not provided are apparent. The distinction between can be clarified.

Since the first tin plating layer 21d and the second tin plating layer 21e have such a thickness, the copper tin alloy region 21f is suppressed from being exposed to the outside (that is, the surface of the first tin plating layer 21d). Here, the standard electrode potential of copper-tin alloy is generally higher than the standard electrode potential of tin, although it varies depending on its composition. That is, the difference in standard electrode potential between the copper-tin alloy and the aluminum material of the core wire 11 (the copper-tin alloy region 21f is exposed) means that the difference in standard electrode potential between tin and the aluminum material of the core wire 11 (copper-tin alloy region 21f). Is not exposed). Therefore, by suppressing the exposure of the copper-tin alloy region 21f, galvanic corrosion that occurs between the core wire 11 of the electric wire 10 and the copper-tin alloy region 21f is suppressed as compared with the case where the copper-tin alloy region 21f is exposed.

On the other hand, the surface treatment applied to the contact portion 31 is slightly different from the surface treatment applied to the barrel portion 41, as described above. In the surface treatment applied to the contact portion 31, the base material layer 21a, the nickel layer 21b, the copper underlayer 21c, and the first tin plating layer 21d of the terminal fitting 20 are laminated in this order (FIG. 2(d See)). That is, the contact portion 31 is not provided with the second tin plating layer 21e (third layer) provided on the barrel portion 41. This is because, for example, when the second tin plating layer 21e is provided on the contact portion 31, the contact pressure at the time of connecting the mating terminal and the contact portion 31 (which is formed into a tubular shape as shown in FIG. 1) increases, This is because it may be difficult to connect the mating terminal and the terminal fitting 20.

Next, a method for manufacturing the electric wire with terminal 1 according to the present embodiment will be described with reference to FIG. In the following description, for convenience, the nickel layer 21b is not shown in the flowchart of the forming process.

First, for example, a metal plate material M such as a copper plate corresponding to the base material layer 21a is prepared (step SS). Then, a nickel layer 21b is formed on the surface of the metal plate material M (base material layer) as a base layer for surface treatment in each of the following steps.

Then, a copper underlayer 21c is formed as a first layer on the outer surface of the nickel layer 21b (step S1). Then, a first tin plating layer 21d is formed as a second layer on the outer surface of the base layer 21c (step S2).

Next, the metal plate material M is punched and pressed so as to have the primary molded body 22 having a shape corresponding to the expanded shape of the terminal fitting 20 (step S3). In the primary molded body 22, a plurality of expanded terminal fittings 20 are connected by a carrier 23 to be integrated. By punching the primary molded body 22 from the metal plate material M in this step, the end surface E of the primary molded body 22 is exposed to the outside in both the contact portion 31 and the barrel portion 41.

Then, in the primary molded body 22 formed up to the second layer (first tin-plated layer 21d), a portion corresponding to the barrel portion 41 of the terminal fitting 20 is molded into a preliminary shape 41a capable of receiving the core wire 11 (step S4). .. Further, the portion 31a corresponding to the contact portion 31 is formed into the shape of the contact portion 31 (step S5). The preliminary shape 41a is, for example, a shape having a U-shape in a cross section orthogonal to the longitudinal direction of the primary molded body 22. The forming of the preliminary shape (step S4) and the forming of the contact portion 31 (S5) may be performed in the reverse order or may be performed at the same time.

Next, the second tin plating layer 21e, which is the third layer, is formed on the outer surface of the portion having the preliminary shape 41a (step S6). At this time, the second tin plating layer 21e is formed on the portion corresponding to the barrel portion 41 and the connecting portion 32 and the carrier 23, and the second tin plating layer 21e is not formed on the portion corresponding to the contact portion 31. The second tin plating layer 21e is preferably formed to have a thickness of 3.0 μm or more and 7.0 μm or less as described above. By forming the second tin plating layer 21e on the barrel portion 41 and the like in this step, the end surface E of the barrel portion 41 and the like is covered with the second tin plating layer 21e and is not exposed to the outside. On the other hand, the end surface E of the contact portion 31 remains exposed to the outside.

Finally, the barrel portion 41 is swaged so as to wrap the electric wire 10. At this time, the rear part of the barrel part 41 is wrapped around the coating 12 and the front part of the barrel part 41 is crimped around the core wire 11. Then, the terminal fitting 20 is separated from the carrier 23 (step S7). At this time, in the barrel portion 41, the entire base material layer 21a including the end surface E is not exposed to the outside. Therefore, the occurrence of galvanic corrosion between the copper base material layer 21a and the core wire 11 is appropriately suppressed. When the terminal fitting 20 is separated from the carrier 23, the copper Ma may be exposed at the cut surface. However, since the cut surface is located at the coating 12 portion of the electric wire 10, it should be in direct contact with the core wire 11. And usually does not cause galvanic corrosion.

As described above, according to the electric wire with terminal 1 according to the present embodiment, the barrel portion 41 crimped to the core wire 11 made of aluminum or aluminum alloy is copper or copper alloy from the side far from the core wire 11. The base layer 21c containing tin, the first tin plating layer 21d containing tin, and the second tin plating layer 21e containing tin are provided in this order. Therefore, the barrel portion 41 contacts the core wire 11 via the second tin plating layer 21e. That is, rather than the difference in the standard electrode potential (parameter related to the susceptibility to corrosion) between copper or a copper alloy, which is a general material of the terminal fitting 20, and aluminum or an aluminum alloy, the tin forming the second tin plating layer 21e is Since the difference in standard electrode potential from aluminum or aluminum alloy is smaller, galvanic corrosion in the terminal fitting 20 can be suppressed.

The thickness a of the first tin-plated layer 21d in the stacking direction is more than the thickness b of the copper-tin alloy region 21f in the stacking direction formed by tin contained in the first tin-plated layer 21d and copper contained in the underlayer 21c. Is also configured to be large. Further, the thickness a of the second tin-plated layer 21e in the stacking direction is such that the first tin-plated layer 21d is not exposed to the outside due to the deformation of the second tin-plated layer 21e when the barrel portion 41 is pressure-bonded to the core wire 11. In the example, the thickness is 3.0 μm or more and 7.0 μm or less). Therefore, the copper tin alloy region 21f is prevented from being exposed to the outside due to the deformation of the second tin plating layer 21e. Therefore, galvanic corrosion in the terminal fitting 20 can be suppressed.

Further, the contact part 31 has a base layer 21c containing copper or a copper alloy and a first tin plating layer 21d containing tin in this order of lamination from the side far from the mating terminal, and is provided in the barrel part 41. The second tin plating layer 21e provided is not provided. As a result, it is possible to suppress an increase in contact pressure when connecting the mating terminal and the contact portion 31, and to easily connect the mating terminal and the terminal fitting 20.

Further, according to the method of manufacturing the electric wire with terminal according to the present embodiment, the primary molded body 22 having a shape corresponding to the terminal fitting 20 is molded from the metal plate material M, and the primary molded body 22 is crimped to the core wire 11. At this time, a base layer 21c containing copper or a copper alloy and a first tin plating layer 21d containing tin are formed in this order from the side remote from the core wire 11. As described above, since the plating treatment is performed after the primary molding, the copper alloy is not exposed from the end surface of the barrel portion 41 and the like, so that galvanic corrosion between copper and tin can be suppressed.

In addition, since the second tin plating layer 21e containing tin is formed on the portion corresponding to the barrel portion 41 so as to have the preliminary shape 41a, when the molding having the preliminary shape 41a is not performed ( As compared with the case where the second tin plating layer 21e is directly formed on the primary molded body 22), the second tin plating layer 21e is formed thicker because the deformation amount of the portion corresponding to the barrel portion 41 is smaller during the subsequent crimping to the core wire 11. You can do it. Therefore, the second tin-plated layer 21e can be easily formed so that the first tin-plated layer 21d has a thickness that is not exposed to the outside even when the second tin-plated layer 21e is deformed when the core wire 11 is pressure-bonded.

Further, according to the method of manufacturing the electric wire with terminal according to the present embodiment, the second tin plating layer 21e is formed so that the thickness of the second tin plating layer 21e is 3.0 μm or more and 7.0 μm or less. This makes it possible to more appropriately prevent the copper-tin alloy region 21f from being exposed to the outside.

<Other aspects>
The present invention is not limited to the above-mentioned embodiments, and various modifications can be adopted within the scope of the present invention. For example, the present invention is not limited to the above-described embodiments, and can be modified, improved, and the like as appropriate. In addition, the materials, shapes, dimensions, numbers, locations, etc. of the constituent elements in the above-described embodiments are arbitrary and are not limited as long as the present invention can be achieved.

For example, in the barrel portion 41 in the above-described embodiment, the nickel layer 21b and the base layer 21c are sandwiched between the base material layer 21a and the first tin plating layer 21d. However, the first tin plating layer 21d may be directly provided on the base material layer 21a. In this case, the base material layer 21a corresponds to the first layer.

Here, the features of the above-described embodiment of the electric wire with terminal and the method of manufacturing the electric wire with terminal according to the present invention will be briefly summarized and listed below in [1] to [4].
[1]
A terminal fitting (which includes an electric wire having a core wire (11) made of aluminum or an aluminum alloy, a barrel portion (41) crimped to the core wire (11), and a contact portion (31) connected to a mating terminal ( 20), and an electric wire (1) with a terminal comprising:
The barrel portion (41) is
A first layer (21c) containing copper or a copper alloy, a second layer (21d) containing tin, and a second layer containing tin from the side far from the core wire (11) when pressure-bonded to the core wire (11). 3 layers (21e) and, in this stacking order,
The contact part (31) is
When the core wire (11) is pressure-bonded to the core wire (11), the first layer (21c) and the second layer (21d) are arranged in this order from the side remote from the core wire (11),
The second layer (21d) is
The second layer rather than the thickness (b) in the stacking direction of the copper-tin alloy region (21f) generated by the tin contained in the second layer (21d) and the copper contained in the first layer (21c). The core wire (11) side surface of (21d) and the core wire (11) side surface of the first layer (21c) are configured to have a large distance (a) in the stacking direction,
The third layer (21e) is
The thickness of the third layer (21e) in the stacking direction is the second layer (21d) due to deformation of the third layer (21e) when the barrel portion (41) is pressure-bonded to the core wire (11). ) Is a thickness that is not exposed to the outside,
Electric wire with terminal (1).
[2]
In the electric wire (1) with a terminal according to the above [1],
The third layer (21e) has a thickness of 3.0 μm or more and 7.0 μm or less,
Electric wire with terminal (1).
[3]
An electric wire (10) having a core wire (11) made of aluminum or an aluminum alloy, a barrel portion (41) crimped to the core wire (11), and a contact portion (31) connected to a mating terminal. A method of manufacturing an electric wire with a terminal for manufacturing an electric wire with a terminal (1) including a terminal fitting (20),
A first layer (21c) containing copper or a copper alloy and a second layer (21d) containing tin from the side far from the core wire (11) when the metal plate material (M) is pressure-bonded to the core wire (11). ), and a step of treating the metal plate material (M) so as to have
Molding a primary molded body (22) having a shape corresponding to the terminal fitting (20) from the metal plate material (M);
A first layer (21c) containing copper or a copper alloy and a second layer containing tin from the side far from the core wire (11) when the primary molded body (22) is pressure-bonded to the core wire (11). (21d), and a step of treating the primary molded body (22) so as to have
Molding a portion of the primary molded body (22) corresponding to the barrel portion (41) so as to have a preliminary shape capable of receiving the core wire (11);
Molding a portion of the primary molded body (22) corresponding to the contact portion (31) so as to have the shape of the contact portion (31);
When the portion corresponding to the barrel portion (41) having the preliminary shape is pressed to the core wire (11) from the side distant from the core wire (11), the first layer (21c) and the second layer A step of treating the portion corresponding to the barrel portion (41) so as to have a layer (21d) and a third layer (21e) containing tin in this stacking order;
Crimping the barrel portion (41) having the first layer (21c), the second layer (21d) and the third layer (21e) to the core wire (11).
Manufacturing method of electric wire with terminal.
[4]
In the method for manufacturing the electric wire with a terminal (1) according to the above [3],
A treatment is applied to a portion corresponding to the barrel portion (41) such that the thickness of the third layer (21e) is 3.0 μm or more and 7.0 μm or less.
Manufacturing method of electric wire with terminal.

1 Electric wire with terminal 10 Electric wire 11 Core wire 20 Terminal fitting 21c Base layer (first layer)
21d stannous plating layer (second layer)
21e Second tin plating layer (third layer)
21f Copper-tin alloy region 22 Primary molded body 31 Contact part 41 Barrel part/core wire crimping part 41a Preliminary shape M Metal plate material a Thickness of stannous plating layer (second layer) b Thickness of copper-tin alloy region

Claims (4)

An electric wire with a terminal, comprising an electric wire having a core wire made of aluminum or an aluminum alloy, and a terminal fitting having a barrel portion crimped to the core wire and a contact portion connected to a mating terminal,
The barrel portion is
Having a first layer containing copper or a copper alloy, a second layer containing tin, and a third layer containing tin from the side distant from the core wire when pressure-bonded to the core wire, in the order of lamination,
The contact portion is
When it is crimped to the core wire, from the side far from the core wire, the first layer, and the second layer, in the order of lamination,
The second layer is
The core-side surface of the second layer and the surface of the first layer of the copper-tin alloy region formed by the tin contained in the second layer and the copper contained in the first layer in the stacking direction. It is configured such that the distance in the stacking direction between the surface on the core wire side is large,
The third layer is
The thickness of the third layer in the stacking direction is configured such that the second layer is not exposed to the outside due to deformation of the third layer when the barrel portion is pressure-bonded to the core wire. The
Electric wire with terminal. The electric wire with a terminal according to claim 1,
The thickness of the third layer is 3.0 μm or more and 7.0 μm or less,
Electric wire with terminal. For manufacturing an electric wire with a terminal, which includes an electric wire having a core wire made of aluminum or an aluminum alloy, and a terminal fitting having a barrel portion crimped to the core wire and a contact portion connected to a mating terminal In the method of manufacturing an electric wire with a terminal,
The metal plate material has a first layer containing copper or a copper alloy and a second layer containing tin from the side distant from the core wire when the metal plate material is pressure-bonded to the core wire, so that the metal plate material has a second layer containing tin in this order of lamination. A step of treating the metal plate material,
Molding a primary molded body having a shape corresponding to the terminal fitting from the metal plate material;
When the primary molded body has a first layer containing copper or a copper alloy and a second layer containing tin from the side distant from the core wire when it is pressure-bonded to the core wire, in this order of lamination. A step of treating the primary molded body,
Molding a portion of the primary molded body corresponding to the barrel portion so as to have a preliminary shape capable of receiving the core wire;
A step of molding a portion corresponding to the contact portion of the primary molded body so as to have the shape of the contact portion;
A portion corresponding to the barrel portion having the preliminary shape includes the first layer, the second layer, and a third layer containing tin from the side farther from the core wire when pressure-bonded to the core wire. A step of treating the portion corresponding to the barrel portion so as to have this stacking order;
Pressure-bonding the barrel portion having the first layer, the second layer, and the third layer to the core wire.
Manufacturing method of electric wire with terminal. The method for manufacturing an electric wire with a terminal according to claim 3,
Treatment is applied to a portion corresponding to the barrel portion so that the thickness of the third layer is 3.0 μm or more and 7.0 μm or less,
Manufacturing method of electric wire with terminal.

Images