JP2003229183A - Connection structure of aluminum electric wire for preventing electric corrosion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection structure of an aluminum electric wire for preventing an electric corrosion at a contact section in connecting electric members with a large standard electrode potential difference. <P>SOLUTION: In a connection structure electrically connecting an aluminum electric wire with a copper electric wire, electric connection of an aluminum electric wire with a copper electric wire is constituted by an electric wire connection member 1 made of a single material with a standard electrode potential value, intermediate between that of aluminum and that of copper, or an electric wire connection member 2 made of an electrical conductor composed of 3 parts, namely, a part 2a coupled with a core wire section of the aluminum electric wire, a part 2c coupled with a core wire section of the copper electric wire and an intermediate part 2b formed between the part coupled with the core wire section of the aluminum electric wire and the part coupled with the core wire section of the copper electric wire and with a conductor with the standard electrode potential satisfying: aluminum < the part connected with the core wire section of the aluminum electric wire < the intermediate part < the core wire section of the copper electric wire < copper. As the standard electrode potential changes little by little in stages through the electric wire connection member, the occurrence of electric corrosion can be restrained. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum electric wire connection structure for preventing electrolytic corrosion, and more particularly to an aluminum electric wire connection structure for preventing electric corrosion, which is preferably used for connection with copper terminals.

[0002]

2. Description of the Related Art Conventionally, in electric power fields such as power plants and overhead power transmission lines, aluminum electric wires having a core made of an aluminum-based material have been used as electric power lines because they are lightweight and have excellent electric conductivity. Generally, when electric wires are used to distribute electricity to various electric devices, electric wire connection terminals are attached to the end portions of the electric wires. For example, as an electric wire connecting terminal applied to the above-mentioned aluminum electric wire, for example, one shown in FIG. 3 is known.

FIG. 3 is an external perspective view showing a conventional electric wire connecting terminal and an aluminum electric wire. FIG. 3 (a) is an exploded (before connection) perspective view, and FIG. 3 (b) is a view showing a joined state. Is. The wire connection terminal 11 is integrally formed of a metal material such as aluminum or aluminum alloy. This wire connection terminal has a fastening portion 12 having a through hole 14 formed at a tip thereof through which a fastening means (not shown) such as a bolt can penetrate, and an insertion port 15 into which a terminal portion of an aluminum wire is inserted at a base end. It has a cylindrical electric wire connecting portion 13.

When connecting an aluminum electric wire to this electric wire connecting terminal, the aluminum core wire portion 17 which is exposed by peeling the outer skin of the end portion of the aluminum electric wire 16 is inserted, and the electric wire connecting portion is connected with a tool not shown. Compress from the outside and crimp. As a result, the wire connection terminal and the aluminum wire are inseparably pressure-bonded as shown in FIG. In the figure, a state in which the electric wire connecting portion is caulked into a hexagonal column shape and crimped is illustrated.

[0005]

In the fields of automobiles, OA equipment, and home appliances, in contrast to the above-mentioned electric power field, a copper electric wire having a core wire made of a copper-based material having excellent electrical conductivity is a signal wire. Used as a power line.

[0006] Above all, in the field of automobiles, since the performance and performance of vehicles have been rapidly advanced, the number of copper electric wires used increases with the increase of various electric equipments and control equipments mounted on vehicles. The current situation is that there is a tendency. Recently, electric vehicles and fuel cell vehicles, which have less impact on the environment, are being actively developed. However, in this type of vehicle, it is necessary to extract a large amount of energy from batteries, fuel cells, etc. A power line having a larger diameter than that of a conventional signal line is required as an electric wire connected to.

[0007] Under such circumstances, when attempting to improve fuel efficiency by reducing the weight of a vehicle, the total weight of the electric wires used per vehicle cannot be neglected, and the weight can be reduced. Can be the subject of. Particularly in electric vehicles, fuel cell vehicles, and the like, which are expected to become popular in the near future, since the batteries and fuel cells to be mounted on the vehicle itself are heavy, there is a strong demand for making the vehicle lighter. For this the purpose of achieving further weight reduction, density is used in the aluminum core wire is one of the density of 8.96 g / cm ³ Copper compared to the the 2.70 g / cm ³ to about 3 minutes Aluminum Electric wires have recently attracted particular attention in the automobile field.

However, although the aluminum electric wire itself has already been used in the electric power field such as an overhead power transmission line as described above, it has not been so widely used in the automobile field because it has not been required so far. It is a thing. When actually using the aluminum electric wire for automobiles, the following two problems mainly occur.

The first is the problem of the oxide film formed on the aluminum surface in air. Since aluminum is extremely active, when the outer skin of the end portion of the aluminum electric wire is peeled off and the aluminum core wire portion is exposed, the surface is exposed to the outside air and oxidized, and an oxide film made of aluminum oxide is formed. . This oxide film is extremely thin, about 100 liters or less, but because it is dense, hard, and insulating,
If electrical connection is made with the aluminum core wire portion and the wire connection terminal being interposed, the electrical resistance increases.

Therefore, in the conventional method of crimping the wire connecting portion to join the wire and the wire connecting terminal, the hard oxide film formed on the surface of the aluminum core wire cannot be destroyed, In order to avoid this problem, good electrical characteristics cannot be obtained, and in the above-mentioned power field, etc., in order to avoid this problem, the oxide film on the aluminum core wire portion should be applied immediately before connecting the aluminum wire and the power supply connection terminal. It is generally performed in advance by physically destroying / removing using a wire brush or the like.

However, it is not realistic to perform this kind of work in the field of automobile manufacturing, which uses a large number of electric wires and is mass-produced, because it is very inefficient and deteriorates productivity. In addition, the amount of oxide film removed is not constant due to differences in operators, and as a result, there is a problem in that variations in electrical characteristics become large and the quality becomes unstable. In order to solve this problem, there has been developed a structure in which the oxide film is naturally destroyed and removed at the time of fastening of the aluminum core portion and the connecting terminal to directly join with the unoxidized aluminum.

Secondly, there is a problem of electrolytic corrosion (corrosion between different metals). When performing wiring work not limited to aluminum electric wires,
It is necessary to attach a connecting terminal to the electric wires in order to connect the electric wires to each other, to connect the electric wires to the terminals of the external electric device, or to connect to the external electric device. As described above, many of these terminals and electric wires are formed of copper having excellent electric characteristics. For this reason, there are many cases in which it is necessary to contact and bond aluminum and copper, but when dissimilar metals with different standard electrode potentials are bonded, electrolytic corrosion occurs at this contact / bond part. Become.

In particular, since the standard electrode potential of copper is + 0.34V and the standard electrode potential of aluminum is -1.66V, the difference between the standard electrode potentials of the connectors connected to the aluminum core portion is 2 mm. It will be as large as 0.000V. For this reason, when running in the rain, washing the car, or when exposed to water due to dew condensation, ionization of the aluminum core, which is electrically base, progresses and corrosion is promoted. In addition to destabilizing the characteristics, there is a possibility that the contact resistance may increase, the electrical resistance may increase due to a decrease in the wire diameter due to corrosion, and further disconnection may occur. As a result, malfunctioning and functional stoppage of the electrical components may occur.

In order to prevent such electrolytic corrosion, generally, a method of forming a coating film by applying a water resistant coating to a portion where different metals are in contact with each other or a method of covering with a waterproof cap is used. A method of preventing moisture from directly adhering to the joint portion is used.

However, also in the method of forming a coating film by coating the contact portion of dissimilar metals to prevent the coating film from being exposed to water, electrolytic corrosion progresses under the coating film depending on the use conditions, and It is known that blister (blister) occurs and corrosion of aluminum, which is electrochemically base, progresses. Therefore, it cannot be said that the protection by the coating film has a sufficient effect as the prevention of electrolytic corrosion.

Further, even when a waterproof cap is used, it is difficult to completely prevent water from getting wet, and the cap is generally made of resin or rubber which is an insulator, but deterioration is caused. Depending on the case, the original function may be lost.

The problem to be solved by the present invention is to provide a terminal structure of an aluminum electric wire which can prevent electrolytic corrosion at the connecting portion even when connecting an aluminum electric wire and a copper electric wire.

[0018]

In order to solve this problem, the invention according to claim 1 is a connection structure for electrically connecting an aluminum electric wire and a copper electric wire by an electric wire connecting member, wherein the electric wire connecting member is aluminum. The gist is that it is formed by a conductor having a standard electrode potential of an intermediate value of copper.

With such a structure, the standard electrode potential changes gradually between the aluminum electric wire and the electric wire connecting member and between the electric wire connecting member and the copper electric wire, and the occurrence of electrolytic corrosion can be suppressed. .

In this case, the electric wire connecting member is F
It is desirable to be formed of a conductor of e, Zn, or Sn.

Further, the invention according to claim 3 is a connection structure for electrically connecting an aluminum electric wire and a copper electric wire by an electric wire connecting member, and a portion where the electric wire connecting member is joined to the aluminum electric wire core portion, and a copper wire. It has a part to be joined to the wire core part, an intermediate part to be formed between the part to be joined to the aluminum wire core part and the part to be joined to the copper wire core part, and the three parts are different standard electrodes. A conductor which is formed of a conductor having a potential, and the standard electrode potential of the conductor forming the three parts is the following conditional expression 1, that is, the standard electrode potential of aluminum <a conductor forming a part to be joined to the aluminum wire core part The standard electrode potential of <the standard electrode potential of the conductor forming the intermediate portion <the standard electrode potential of the portion forming the portion to be joined to the copper wire core wire <the standard electrode potential of copper> To do.

In this case, the portion of the electric wire connecting member to be joined to the aluminum electric wire core is made of Zn,
It is preferable that an intermediate portion of the electric wire connecting member is formed of Fe, and a portion of the electric wire connecting member that is joined to the copper electric wire core portion is formed of Sn.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1A is a cross-sectional view of a connection structure of an aluminum electric wire and a copper electric wire of an embodiment according to claim 1, and FIG. 1B is a connection structure of an aluminum electric wire and a copper electric wire of an embodiment according to claim 3. FIG. 2 is a cross-sectional view of the structure, and FIG. 2 is an external perspective view of a connection structure of an aluminum electric wire for preventing electrolytic corrosion according to an embodiment of the present invention.

The electric wire connecting member 1 according to claim 1 has a standard electrode potential of a conductor having an intermediate value between −1.66 V of aluminum and +0.34 V of copper, such as Fe (−0.44 V),
It is made of Zn (-0.77V), Sn (-0.14V), etc., and as shown in FIG. 1A, the core wire portion 4 of the aluminum electric wire 3 which is not penetrated is joined to one end thereof. An electric wire insertion hole 9 is formed at the other end of the electric wire insertion hole 10 to which the core wire portion 7 of the copper electric wire 6 is joined.

In the electric wire connecting member 2 according to claim 3, three kinds of electric conductors are laminated and formed, and in each part, the standard electrode potential is the standard electrode potential of aluminum <the part joined to the aluminum wire core portion. Standard electrode potential of the conductor forming the conductor <standard electrode potential of the conductor forming the intermediate portion <standard electrode potential of the portion forming the portion to be joined to the copper wire core wire <conductivity satisfying the standard electrode potential of copper It is formed by the body.
For example, the portion 2a in which the electric wire insertion hole 9 to be joined to the aluminum electric wire core portion 4 is formed is formed of Zn, and the portion 2c in which the copper electric wire core portion 7 and the electric wire insertion hole 10 are formed is formed of Sn, An intermediate portion 2b between the two portions 2a and 2c is formed of Fe.

Each portion 2a, 2 of the wire connecting member 2
The joining of b and 2c may be performed by a method in which the respective parts are in direct contact with each other to ensure electrical connection (conductivity), and solid layer joining or mechanical joining by screws or the like can be used.

As shown in FIGS. 1 (a) and 1 (b), the electric wire insertion holes 9 and 10 formed on both end surfaces of the electric wire connecting members 1 and 2 are installed in one electric wire insertion hole 9 by an aluminum electric wire. 3 is inserted into the other wire insertion hole 10, and the core member 7 of the copper electric wire 6 is inserted into the other wire insertion hole 10. Then, the connecting member is compressed from the outer peripheral surface toward the center by using a die or the like not shown. Staking,
This is performed by crimping with the core wire portions 4 and 7 of the electric wires 3 and 6 inserted into the electric wire insertion holes 9 and 10. As a result, an electric connection between the aluminum electric wire and the copper electric wire is formed via the electric wire connecting member 1 or 2.

According to the invention described in claim 1 or 2,
Since the core portion 4 of the aluminum electric wire 3 and the core portion 7 of the copper electric wire 6 do not directly contact each other and are electrically connected through the electric wire connecting member 1, when the electric wire connecting member 1 is formed of Fe. When the standard electrode potential difference between the aluminum wire core portion 3 and the wire connecting member 1 is 1.22V, the standard electrode potential difference between the wire connecting member 1 and the copper wire core portion is 0.78V, and Zn is formed. Is formed by a standard electrode potential difference between the aluminum wire core portion 3 and the wire connecting member 1 of 0.89V, and a standard electrode potential difference between the wire connecting member 1 and the copper wire core portion of 1.11V, Sn. In this case, the standard electrode potential difference between the aluminum wire core portion 3 and the wire connecting member 1 is 1.52V, and the standard electrode potential difference between the wire connecting member 1 and the copper wire core portion is 0.48V.
Compared to the standard electrode potential difference of 2.00 V when the aluminum wire core wire portion 3 and the copper wire core wire portion 6 are in direct contact with each other, the potential difference is small and changes stepwise.

According to the third or fourth aspect of the present invention, the core wire portion 4 of the aluminum electric wire 3 and the core wire portion 7 of the copper electric wire 6 are electrically connected via the electric wire connecting member 2. In addition to not making direct contact, the standard electrode potential difference in the wire connecting member 2 is 0.33 V between the part 2a joined to the core part 4 of the aluminum electric wire 3 formed of Zn and the intermediate part 2b formed of Fe. , Between the intermediate portion 2b formed of Fe and the portion 2c of the copper electric wire 6 formed of Sn and joined to the core portion 7 gradually changes to 0.3V in a small stepwise manner. The electrode potential difference can be further reduced.

Although the embodiment of the present invention has been described above, the connection structure of the aluminum electric wire for preventing electrolytic corrosion according to the present invention is not limited to the above-described embodiment, and does not depart from the gist of the present invention. Various modifications are possible.

For example, in the present invention, the connection structure of the aluminum electric wire and the copper electric wire is shown. However, the mutual standard electrode potential difference is large, and when directly connected / contacted, a corrosive battery is formed and electrolytic corrosion occurs. It is applicable to connection between materials and is not limited to the materials shown in the invention of the present application, and the material of the wire connecting member may be a conductor having a standard electrode potential difference of an intermediate value between aluminum and copper. However, the present invention is not limited to Fe, Zn, and Sn described in the claims. The invention according to claim 3 or 4 has shown an example of a three-layer laminated structure of three kinds of metals, but if the standard electrode potential is changed stepwise between the respective parts, the intermediate part 2b There is no two parts, or there are two intermediate parts
It may be configured to have more than one.

Although an example of crimping by caulking is shown as a joining form of the wire connecting members 1 and 2 and the aluminum wire core wire portion 4 and the copper wire core wire portion 5, the joining method is not limited to this. For example, screwing can be applied.

[0033]

According to the connection structure of the aluminum electric wire for preventing electrolytic corrosion according to the present invention, the standard electrode potential of the core portion of the aluminum electric wire and the core portion of the copper electric wire is set to an intermediate value between aluminum and copper. It is possible to change the standard electrode potential in small steps by making an electrical connection through an electric wire connecting member formed of a conductor that has, so that a corrosion battery is generated between aluminum and copper. Suppress. As a result, even if the electric conductors having a large standard electrode potential difference such as aluminum or copper are electrically connected to each other, electrical connection can be achieved without causing electrolytic corrosion.

[Brief description of drawings]

1A is a sectional view of a connection structure of an aluminum electric wire for preventing electrolytic corrosion according to an embodiment of claim 1, and FIG. 1B is an aluminum wire for preventing electrolytic corrosion according to an embodiment of claim 3; It is sectional drawing of the connection structure of an electric wire.

FIG. 2 is an external perspective view of an aluminum electric wire connection structure for preventing electrolytic corrosion according to an embodiment of the present invention.

FIG. 3 is an external perspective view showing a conventional electric wire connecting terminal and an aluminum electric wire.

[Explanation of symbols]

1 wire connecting member 2 wire connecting member 2a part of the wire connecting member that joins the core of the aluminum wire 2b middle part of the wire connecting member 2c part of the wire connecting member that joins the core of the copper wire 3 aluminum wire 4 aluminum Core part 5 of the electric wire 5 Aluminum wire covering material 6 Copper electric wire 7 Copper electric wire core part 8 Copper electric wire covering material 9 Electric wire insertion hole 10 Electric wire insertion hole 11 Connection terminal 12 Fastening part 13 Electric wire connection part 15 Electric wire insertion hole 17 Wire core

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hirotaka Yamada             1-7-10 Kikuzumi, Minami-ku, Nagoya-shi, Aichi             Auto Network Technical Laboratory Co., Ltd. F term (reference) 5E085 BB01 BB12 CC03 DD13 EE24                       FF01 GG11 GG21 JJ03 JJ50                 5G355 BA01 BA11 CA06

Claims (4)

[Claims] 1. A connection structure for electrically connecting an aluminum electric wire and a copper electric wire with an electric wire connecting member, wherein the electric wire connecting member is formed of a conductor having a standard electrode potential intermediate between aluminum and copper. A characteristic aluminum wire connection structure that prevents electrolytic corrosion. 2. The aluminum electric wire connection structure for preventing electrolytic corrosion according to claim 1, wherein the electric wire connection member is formed of any one of Fe, Zn, and Sn. 3. A connection structure for electrically connecting an aluminum electric wire and a copper electric wire by means of an electric wire connecting member, wherein the electric wire connecting member is joined to the aluminum electric wire core portion, and the portion is joined to the copper electric wire core portion. An intermediate portion formed between a portion joined to the aluminum electric wire core portion and a portion joined to the copper electric wire core portion, the three portions being formed of conductors having different standard electrode potentials, A connection structure of an aluminum electric wire for preventing electrolytic corrosion, characterized in that a standard electrode potential of a conductor forming the three parts satisfies the following conditional expression 1. Conditional expression 1: Standard electrode potential of aluminum <Standard electrode potential of conductor forming part to be joined to aluminum wire core wire <Standard electrode potential of conductor forming intermediate part <Part to be joined to copper wire core part Standard electrode potential of the part that forms copper <standard electrode potential of copper 4. A portion of the electric wire connecting member that is joined to the aluminum electric wire core portion is formed of Zn, and an intermediate portion of the electric wire connecting member is formed of Fe, which is joined to the copper electric wire core portion of the electric wire connecting member. The connection structure of the aluminum electric wire according to claim 3, wherein the portion to be formed is made of Sn.