JPS6018104B2 - Crimp terminal for aluminum conductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crimp terminal for aluminum conductors.

More specifically, the present invention relates to mass-produced crimp terminals for connecting low-voltage electric wires for low power using aluminum conductors.
BACKGROUND OF THE INVENTION Assembly wires used for wiring in automobiles, etc. have been constructed of steel conductor wires with terminals attached by crimping.

However, in recent years, due to the demand for weight reduction of automobiles, it has been desired to apply aluminum conductors to the low power electric wire conductors used in these assembled electric wires. However, compared to copper, aluminum generally tends to form an insulating oxide film on its surface.

■ Stress relaxation is likely to occur.

■ The coefficient of thermal expansion is larger than that of terminal materials such as yellow steel.

■ Poor corrosion resistance, especially in the presence of moisture.

Due to these characteristics, it has been impossible to make a sufficient electrical connection using a normal crimp terminal for copper wire when connecting using the crimp method. In addition, connections other than the crimping method, such as soldering with aluminum solder, have poor workability and are difficult to meet the requirements for mass production and automation such as assembly wires, and welding also Highly efficient connection workability cannot be expected.

Therefore, various attempts have been made to improve the aluminum conductor connection portion of crimp terminals, but none of them have necessarily satisfied the objective. For example, a structure in which the aluminum conductor's lacquer holding part has a claw-like convex part on the inside of the aluminum conductor's lacquer holding part, in which a nail is set up from the outside in advance, has the effect of destroying the insulating oxide film on the surface of the aluminum conductor, but the conductor itself may be damaged and the wire may be disconnected. In addition to being susceptible to corrosion, moisture tends to accumulate in the punched areas of the slit-shaped parts, and the aluminum conductor is exposed to the outside air, which can lead to problems with corrosion resistance.

As another example, a method has been proposed in which a cylindrical inclusion with a number of holes is inserted in advance into a cylindrical crimp terminal, and then an aluminum conductor is inserted and crimped (for example, US Pat. No. 3,955,044). ing.

However, the drawbacks are that it cannot be said to be suitable for industrial mass production in terms of cost and workability, such as manufacturing cylindrical inclusions, inserting them into crimp terminals, and inserting electric wires into the cylindrical part. was there. Further, terminals have been proposed in which a groove is provided in the U-shaped crimp holding part (for example, US Pat. No. 2,379,567), and a structure in which a recess is provided in place of the groove (for example, US Pat. No. 3,990,143). However, in the case of electric wires for low power use, the wire diameter is generally small, and the terminals used to connect them are not the same as the current copper wire terminals, but are not designed to be excessively large or thick. Even in the case of aluminum conductors, the thickness of the material strips used is limited to a small thickness in order to maintain compatibility with conventional copper terminals. (Normally, the board thickness of terminals for wiring in automobiles is about 0.4 inch thick at most). For terminals processed from such thin material strips,
Effective in destroying the oxide film on the surface of aluminum conductors.
It is difficult to fabricate grooves and recesses with sufficient depth to ensure terminal adhesion, or even if it is possible to fabricate them, the conductor crimps must be made at a higher height than in the case of copper wire to prevent the stress relaxation phenomenon of aluminum conductors. Although strength and high elasticity are required,
Due to the presence of grooves and recesses, the effective cross-sectional area that contributes to the strength of the crimping part is reduced, and the crimping load after repeated heat cycles tends to decrease, resulting in an increase in contact resistance.

The present invention solves the above-mentioned problems, and makes it possible to mass-produce ponytail aluminum conductor electric wires for low power use with ease and excellent workability in the same way as copper conductor electric wires with crimp terminals, and It is an object of the present invention to provide a crimp terminal that enables sufficient connection physically and mechanically and is compatible with conventional copper wire terminals.

The present invention provides a terminal having a male or female type electrical contact part and a wire crimping part, in which the plate thickness of a portion of the material constituting the conductor clamping part of the wire crimping part is equal to that of the material constituting the electric saddle shark part. This crimp terminal for an aluminum conductor is characterized in that the crimp terminal is larger than the plate thickness of the aluminum conductor, and has a concave portion or a convex portion on the inner wall of the conductor support portion. In the present invention, it is optimal for the thickness of the material forming the conductor holding part to be at least 1.3 times the thickness of the material forming the electrical contact part in order to obtain a good connection.

In the present invention, the term "aluminum conductor" refers to aluminum or an aluminum alloy, or a solid wire or a continuous wire that has been subjected to surface treatment such as plating, and in particular, an aluminum alloy whose 0.2% yield strength is higher than that of ordinary electrical aluminum. Alternatively, it is preferable to use a conductor that has been surface-treated.

In addition, the material constituting the terminal has a hardness higher than that of the aluminum conductor so that the oxide film on the surface of the aluminum conductor can be effectively destroyed by the recesses or protrusions provided on the inner wall of the conductor holding part, and preferably has a micro Vickers hardness of 150 or more. A highly elastic material that is easy to prevent stress relaxation is preferable, and copper alloys such as brass, stainless steel, etc. are suitable.

In addition, in order to obtain even better electrical connections and to prevent contact corrosion of aluminum conductors, it is desirable to plate the terminal material or terminal with tin, lead, indium, or an alloy thereof. . The portion where the plate thickness should be increased is at least the portion of the conductor clamping portion where the exposed portion of the aluminum conductor is crimped, and the subsequent portion where the electric wire is clamped together with the insulation coating is not necessarily required. Note that it is preferable that the covered wire clamping portion of the aluminum conductor wire not have a structure in which the wire is crimped too strongly, since the aluminum conductor is more easily broken by bending than the copper conductor.

In addition, in the present invention, it is specified that the thickness of the thick part of the material is 1.3 times or more of the thin part of the material. This is because despite the effort involved, the effect of improving connectivity is small.

Further, the shape of the recess or projection provided on the inner wall of the conductor holding part is not limited to the shape of the groove-like recess as described above, and other shapes such as a circular recess can be arbitrarily selected. The present inventors have confirmed through experience that in order to sufficiently destroy the oxide film on the surface of the conductor and to guarantee the terminal adhesion, it is desirable that the depth or height thereof be 0.2 skin or more. .

Further, it is desirable to have a plurality of concave portions or convex portions.

Hereinafter, the present invention will be explained according to examples using the drawings.

FIGS. 1 and 2 are perspective views showing examples of material strips used in manufacturing embodiments of the terminal of the present invention. The thickness of the thin part shown in Figures 1 and 2 is 0.32, and the thickness of the thick part is 0.6.
Microvits hardness 18 with stepped ribs
Two types of yellow steel strips of 0 to 190 mm were prepared, and the yellow steel strip shown in FIG. 1 was pre-plated with a copper undercoat to a thickness of about 1 mm, and then tin-plated to a thickness of 5 mm. After that, use the usual method to cut a groove into the inner wall of the conductor holding part at a depth of 0.3 mm, so that the upper surface of the strip shown in Figure 1 becomes the inner wall of the conductor. and groove spacing 0.
A terminal having four grooves in a direction perpendicular to the direction of the five ribs was manufactured. Fig. 3 shows a group of terminals manufactured after plating the Aoi steel strip shown in Fig. 1, and Fig. 4 shows an enlarged view of the wire crimping part of the terminal shown in Fig. 3 (hereinafter referred to as This terminal example will be referred to as Invention Example 1). Next, in the same manner, from the yellow steel strip shown in FIG. 0.3
We manufactured a terminal with a recessed part in the ribs.

This terminal group was also subjected to tin plating treatment to a thickness of 10 mm (hereinafter, this terminal example will be referred to as Invention Example 2). An enlarged view of the wire crimping portion of this terminal is shown in FIG. In FIGS. 3 to 5, 1 is an electrical contact part, 2 is a conductor holding part, 3 is a covered wire holding part, 4 is a groove, and 5 is a recessed part. Also, for comparison, the plate thickness is 0.
．． A conventional crimp terminal for copper wire manufactured from a brass strip with a uniform thickness of 32 ribs and tinned to a thickness of 10 mm (hereinafter referred to as Comparative Example 1) Yellow strip steel of the same machine as Comparative Example 1 From the strip, on the inner wall of the conductor clamping part, there is a 0.3 willow depth 0.1 fence in the groove, and a tin crimp terminal with 4 grooves in the direction perpendicular to the axial direction on the side with a gap of 0.5 between the grooves. Plated with a thickness of 10 mm (hereinafter referred to as
(referred to as Comparative Example 2) was prepared. Next, 0.2% yield strength 10k9/sail 2, elongation 25%, made of aluminum alloy made by adding 1% iron to ordinary electrical aluminum.
These terminals were crimped using exactly the same method as usual to a single wire with a PVC coating on the 0.4 side and a 0.5 side ◇ stranded wire made of 7 Oka core twisted Hata wires.

FIG. 6 shows a cross section of the conductor crimping part when the terminal shown in FIG. 4 is used, and FIG.
A longitudinal section cut along the plane is shown.

In the figure, the same symbols as in FIG. 4 indicate the same parts,
6 is an aluminum alloy conductor, and 7 is an insulating coating. Table 1 shows the results of measuring the terminal adhesion strength and contact resistance values of these samples before and after the heat cycle test. From Table 1, it can be seen that the terminal according to the present invention has a greater terminal adhesion force and a significantly lower contact resistance value than the terminal of the comparative example, and these performances hardly deteriorate even after repeated heat cycles.

On the other hand, in the comparative example, the characteristics were significantly deteriorated and it could not be put to practical use. This is due to the fact that with the terminal of the present invention crimped, a large terminal fixing force is obtained due to the deep recess of the conductor crimping part and the strong elastic force of the thick crimping member, and also because the terminal is crimped into the deep recess made of a high hardness material. During the plastic deformation process, the oxide film on the surface of the aluminum alloy conductor is sufficiently destroyed, resulting in a good electrical connection, and due to the excellent tightening force of the thick crimped part,
The airtightness between the conductor and the terminal is maintained, and the excellent elasticity and sticking effect of the thick crimp material ensure not only good mechanical properties but also good electrical connection even after repeated heat cycles. This is to be done. Furthermore, in the terminal of the present invention, since the conductor crimping portion is isolated from the outside air, there is less concern about corrosion resistance as well as the effect of the plating layer.

As described above, in the terminal of the present invention, the thickness of the material constituting the conductor clamping part of the wire crimping part is larger (preferably 1.3 times larger) than the thickness of the material constituting the electric wire contact part. that's all)
and has a concave or convex part on the inner wall of the conductor holding part Table 1 Note) 1) *EP "The heat cycle is 120℃ in the atmosphere,
The repetition of holding for 45 minutes → holding at room temperature for 15 minutes was counted as one time.

2) Terminal fixing force marked with ★★ is the load that causes the terminal and wire to bulge in the axial direction and cause the wire to come out or break.

Since it is a crimp terminal for copper conductors, it can not only be crimped easily and efficiently in the same way as conventional terminals for copper wires, but also can be used in recesses of the depth or height necessary to obtain sufficient characteristics in thick parts of the board. Alternatively, since it is possible to form a convex portion, it is possible to obtain a terminal connection having excellent mechanical and electrical properties, and also has the feature that it does not deteriorate over a long period of time. Furthermore, according to the terminal of the present invention, electrical connections can be made in the same way as conventional terminals for copper wires, making it compatible with these terminals and facilitating wiring that uses a mixture of steel conductors and aluminum conductors. It has great effects when used.

[Brief explanation of drawings]

FIGS. 1 and 2 are perspective views showing examples of materials used for manufacturing embodiments of the terminal of the present invention. 3 is a perspective view showing a terminal group manufactured from the material shown in FIG. 1, and FIG. 4 is an enlarged view of the wire crimping portion of the terminal shown in FIG. 3. FIG. 5 is an enlarged view of the wire crimping portion of the terminal manufactured from the material shown in FIG. 2. Fig. 6 is a cross-sectional view of the conductor crimping part when an aluminum conductor wire is connected to the terminal shown in Fig. 4, and Fig. 7 is a longitudinal sectional view taken along the plane A-A' shown in Fig. 6. It is. 1... Electric contact part, 2...
...Conductor holding part, 3... Covered wire clamping part, 4... Groove, 5... Recessed part, 6... Aluminum alloy conductor, 7...
...Insulation coating part. Sir diagram 2 diagram you 3 diagram ☆ 4 diagram 5 diagram outside 6 diagram outside 7 diagram

Claims (1)

[Claims] 1. In a terminal having a male or female electrical contact part and a wire crimping part, the thickness of the part of the material constituting the conductor clamping part of the wire crimping part is equal to that of the part of the material constituting the electrical contact part. 1.3 times or more the plate thickness, and the depth or height of the recess or protrusion on the inner wall of the material constituting the conductor holding portion is 0.2 mm or more, and the material constituting the terminal is , copper alloy with microvits hardness of 150 or more,
A crimp terminal for an aluminum conductor, which is made of iron or an iron alloy, and has a plating layer made of tin, lead, indium, or an alloy thereof on at least the flat part of the inner wall of the conductor holding part.