JP5497321B2 - Compressed stranded conductor, method for producing the same, and insulated wire - Google Patents

Description

  The present invention relates to an insulated wire used for wiring of other electronic devices, medical devices, industrial robots, etc., mainly for mounting on automobiles, and a compressed stranded wire conductor thereof, and a manufacturing method thereof.

There is a strong demand for reducing the weight of automobiles for the purpose of reducing exhaust gas and improving fuel efficiency, especially in electric wires used for automobiles. ing. Among them, the wire harness is no exception, and the diameter of the electric wire for the purpose of reducing the weight has been reduced.
Conventionally, soft copper (concentric stranded) is mainly used as a conductor of an automobile electric wire. However, there is a concern about disconnection at the time of routing due to insufficient strength as the diameter is reduced. Therefore, the actual situation is that the copper alloy is cold worked to improve the strength and measures are taken using work hardening. However, in that case, although the strength is improved and the above-mentioned problem is solved, the elongation is insufficient, and therefore, the problem of being inferior to “flexibility” which is an important characteristic for automobile applications has been pointed out.

Until now, many techniques for manufacturing a stranded wire using strands having different physical properties are known. For example, as in Patent Document 1, pure copper or copper alloy is used for the outer layer wire of the concentric twisted conductor, and a metal wire such as Mo or W having a large elastic coefficient is used for the center line while ensuring conductivity. Thus, a method for improving the bending resistance is known.
Also, as disclosed in Patent Document 2, a method is known in which a conductor is annealed to adjust the tensile strength and ductility (elongation) of an outer layer wire.

JP 7-249315 A JP-A-8-127830

  However, a further reduction in diameter and weight is required for electric wires for automobiles. When the conductor described in Patent Document 1 is subjected to circular compression in order to further reduce the diameter, only the outer layer wire is processed depending on the degree of compression processing, and the outer layer wire excellent in conductivity is compressed to a small diameter. As the cross-sectional area of the outer layer wire decreases, the electrical resistance increases and the conductivity deteriorates. Although it is possible to realize that the final product electric wire has a small diameter, there is a problem in electrical characteristics. In addition, since the manufacturing process described in Patent Document 2 requires an annealing process, there is a problem in that the manufacturing efficiency of the compressed conductor is lowered, and extra time and cost are consumed for manufacturing. As described above, it has been extremely difficult to produce an electric wire having a small diameter, a light weight, and having a high level of strength and elongation at break with good electrical performance.

  Accordingly, an object of the present invention is to provide a lightweight and high-performance compression stranded conductor and insulated wire that are excellent in bending resistance and large in strength (tensile strength), and a manufacturing method thereof.

In order to achieve the above object, the present invention provides a stranded wire conductor in which six outer layer wires are concentrically twisted on the outer periphery of a center line to produce a stranded wire, and the diameter of the stranded wire is reduced. a manufacturing method of a, with the center lines consisting of pure a aluminum above purity 99.99 wt%, the outer layer wire is made from pure 99.99 wt% or more pure copper, the work hardening coefficient of the outer layer line, the central The wire diameter is set to be larger than the work hardening coefficient of the wire, and the diameter reduction processing is performed between the outer diameter D ₀ of the stranded wire before the diameter reduction processing and the outer diameter D ₁ of the compressed stranded wire conductor after the diameter reduction processing. , The ratio (D ₁ / D ₀ ) is 0.88 to 0.98.
Moreover, the compression twisted wire conductor which concerns on this invention is produced with the manufacturing method of the compression twisted wire conductor of Claim 1.
Moreover, the insulated wire which concerns on this invention coat | covers the outer periphery of the said compression strand wire conductor with the insulating layer of the insulating material in which a halogen element is not mix | blended.

According to the method for producing a compression twisted wire conductor of the present invention, the outer layer wire C _{5 having} a work hardening coefficient larger than that of the center line C ₁ is used, and the outer diameter before and after the diameter reducing process is further increased. Since the compression stranded conductor is manufactured by specifying the ratio, the outer layer wire is preferentially processed (diameter reduction processing), and the strength (tensile strength) by work hardening is improved. On the other hand, the center line is less affected by the diameter reduction process than the outer layer line (it does not work harden), so the decrease in elongation and the decrease in conductivity before and after the diameter reduction process are suppressed, and as a result, the strength (tensile strength) ), A stretched wire conductor having good elongation and good conductivity can be manufactured.
In addition, since the compression twisted wire conductor obtained from the production method of the present invention is excellent in bending resistance, the insulated wire obtained by coating the outer periphery of the compression insulation conductor wire with an insulating material is desired to be reduced in weight, such as for automotive applications. Suitable for products.

It is an expanded sectional view of the stranded wire before diameter reduction processing. It is an expanded sectional view of the compression twisted wire conductor after diameter reduction processing. It is an expanded sectional view showing one embodiment of an electric wire concerning the present invention. It is an expanded sectional view of the electric wire which shows a comparative example.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
FIG. 2 is an enlarged cross-sectional view showing an embodiment of a compression stranded conductor according to the present invention, and FIG. 3 shows an electric wire in which the compression stranded conductor is covered with an insulating layer.
The insulated wire 4 of the present invention is composed of a compression stranded wire conductor 2 having six outer layer wires C ₅ around a center line C ₁ , and an insulation layer 3 coated on the outer periphery of the compression stranded wire conductor 2. Is done.
The compression stranded wire conductor 2 has a concentric stranded configuration in which the center line C ₁ having a substantially true circular cross section is disposed in close contact with the outer layer wire C ₅ having an eccentric circular cross section.

FIG. 1 is an enlarged cross-sectional view of the stranded wire 1 before diameter reduction processing, and FIG. 2 is an enlarged cross-sectional view of the compression stranded wire conductor 2 after diameter reduction processing.
The stranded wire 1 is produced using a wire having a work hardening coefficient of the outer layer wire C ₅ larger than that of the center line C ₁ .
By doing so, the outer layer wire C ₅ is work-hardened in the diameter reduction processing (cold processing), and the center line C ₁ is not work hardened and the elongation changes before and after the diameter reduction processing compared to the outer layer wire C _5. No (does not fall).
The work hardening coefficient (n value) is measured by a method defined in JIS Z 2241.
If the work hardening coefficient of the outer layer wire C ₅ is the same as or smaller than the work hardening coefficient of the center line C ₁ , the outer layer wire C ₅ will not be sufficiently work hardened even when the diameter is reduced (cold working). The improvement of the tensile strength of the entire compression stranded conductor obtained cannot be expected.

The center line C _1, copper wire, copper alloy wire, aluminum wire, aluminum alloy wire, iron wire, iron alloy wire and the like can be mentioned, et al are. The copper wire is preferably a wire made of pure copper (purity: 99.99 wt% or more Cu), and the copper alloy wire is a wire made of a Cu-Sn alloy. Specifically, Cu-0.2 wt% to 0.4 wt% A wire made of% Sn alloy is preferred.
The outer layer line C ₅ is larger than the work hardening coefficient of the center line C ₁ .
For example, a pure copper wire (purity: 99.99 wt% or more Cu, work hardening coefficient n ₀ = 0.44) is used as the center line C ₁ , and a copper alloy wire (Cu-0.3 wt% Sn, work hardening coefficient n ₁ = 0.46) is used as the outer layer wire C _5. ) Is preferable.

  In Table 1 to be described later, the pure copper wire is “pure copper”, Cu-0.3 wt% Sn as an example of the copper alloy wire is “Cu-0.3Sn”, the aluminum wire is “aluminum”, and the iron alloy. As an example, a stainless steel wire is represented as “stainless steel” and a steel wire as “steel”.

A compression stranded conductor 2 as shown in FIG. 2 is manufactured by drawing or drawing the stranded wire 1 of FIG. 1 with a die or the like and compressing it in the center direction. When the outer diameter of the compressed stranded wire conductor 2 is D ₁ and the outer diameter of the stranded wire 1 is D ₀ , diameter reduction processing (cold processing) is performed within a range of 0.88 ≦ D ₁ / D ₀ ≦ 0.98. . In the compression stranded wire conductor 2 of FIG. 2, the six outer layer wires C ₅ are cold worked larger than the center line C ₁ . The outer layer wire C ₅ is work hardened larger than the center line C ₁ and the tensile strength is larger than that before the diameter reduction processing, and the center line C ₁ is less work hardened than the outer layer wire C _5. tensile strength before the change as compared to the outer layer line C ₅ is small. Similarly, the elongation of the center line C ₁ is small before and after the diameter reduction processing.

Next, the manufacturing method of the electric wire of this invention is demonstrated.
First, as shown in FIG. 1, to prepare a stranded wire 1 an outer line C ₅ six around the center line C ₁ and twisted concentrically. The stranded wire 1 may be a known stranded wire machine. Further, if the twist pitch is a layer core diameter (center diameter of the outermost layer, for example, a 7-strand strand having an outer diameter of 1 mm strand (one center line, six outer layer wires), the layer core diameter = 1 mm + 0.5 mm + 0.5 mm = 2 mm) is preferably 20 times to 80 times, and more preferably 30 times to 70 times. If it is less than the lower limit, the twist of the stranded wire 1 tends to increase and the productivity tends to decrease. If the upper limit is exceeded, the dispersion of the strands C ₁ and C ₅ increases and the flexibility tends to decrease.
After producing the stranded wire 1, diameter reduction processing (cold processing) is performed using a drawing method or a wire drawing method using a die or the like, and a compressed stranded wire conductor 2 as shown in FIG. 2 is manufactured. At this time, after the diameter reduction processing of the stranded wire 1 in FIG. 1, the outer layer wire C ₅ is uniformly processed so that the overall cross-sectional shape is substantially circular as shown in FIG. The diameter is reduced to D ₁ .

The value of the ratio of the outer diameter D ₁ of the reduced diameter outer diameter of unprocessed stranded 1 D ₀ and diameter compression after processing stranded conductor 2 (D ₁ / D ₀₎ is in the range of 0.88 to 0.98 Thus, the hole diameter of the die to be used is specified. When the diameter of the stranded wire 1 is reduced by the above-described method, the outer layer wire C ₅ is hardened and hardened compared to the center line C ₁ , so that the tensile strength is greater than that before the diameter reduction processing, and the elongation is reduced. Smaller than before processing.
On the other hand, since the center line C ₁ is not work hardened compared to the outer layer line C ₅ , the tensile strength does not change before and after the diameter reduction processing (the change amount is small compared to the outer layer line C ₅ ), and the elongation changes similarly. (The amount of change is small compared to the outer layer line C ₅ ).
In other words, in order to maintain the tensile strength and elongation at a high level, the center line C ₁ and the outer layer wire C ₅ constituting the compression stranded conductor have respective characteristics (the outer layer wire C ₅ has the tensile strength and the center line C ₁ has Compressed stranded conductor 2 having a specific elongation).

Moreover, in the manufacturing method of the compression twisted wire conductor of this invention, since it can obtain the compression twisted wire conductor 2 with which tensile strength and elongation become a high level by passing through an above-described process, There is an advantage in the production process that an annealing process is not required, and after the compression stranded conductor 2 is manufactured, the process can proceed to the process of covering the insulating layer 3 (see FIG. 3), Can be obtained.
At this time, since the outer peripheral surface of the compressed stranded wire conductor 2 is formed in a smooth shape, the coating thickness t of the insulating layer 3 is uniformly coated over the circumferential direction, and the inhibition of the diameter reduction by the insulating layer 3 is prevented. Can be minimized. The insulating layer 3 is made of a material not containing a halogen element.

FIG. 4 is an enlarged cross-sectional view of an insulated wire 14 showing a comparative example (Comparative Example 1).
The value of the ratio of the outer diameter D ₁ of the reduced diameter outer diameter of unprocessed stranded 1 D ₀ and diameter compression after processing stranded conductor 2 (D ₁ / D ₀₎ is greater than 0.98 (0.99) Settings In this comparative example, the outer layer wire C ₅ ′ is not evenly compressed during drawing with a die, so that the overall cross-sectional shape of the produced compression stranded conductor is formed in an eccentric shape. That is, since some of the outer layer wires C ₅ ′ are not compressed as shown in FIG. 4, the tensile strength of the compressed stranded wire conductor cannot satisfy the desired characteristics. Further, since the gap Y is formed between the adjacent outer layer lines C ₅ ′ and the insulating layer 13 is also formed in the gap Y, the insulating layer 13 is not uniformly covered on the outer periphery of the conductor. The coating thickness t ′ of the insulating layer 13 varies greatly in the circumferential direction, the average thickness increases, and the weight of the insulated wire increases.

Then, the value of the ratio of the outer diameter D ₁ of the outer diameter D ₀ and diameter reduction after compression stranded conductor 2 of diameter reduction before the stranded wire ₁ (D 1 / D ₀₎ is a 0.88 smaller In the diameter reduction process using a die, the probability that the compressed twisted wire conductor 2 having a reduced diameter is cut increases and the elongation decreases. As a result, the bending resistance decreases.

Examples of the present invention will be described below.
A compressed stranded conductor having a cross-sectional area of 0.13 mm ² was manufactured using the center line (elementary wire) and outer layer wire (elementary wire) shown in Table 1, and each characteristic was evaluated. The pitch of the stranded wire was 40 times the layer core diameter. The present invention is not limited to these examples.

The work hardening coefficient of pure copper (99.99 wt% or more Cu) described in Table 1 is 0.44, and the work hardening coefficient of Cu-0.3 wt% Sn (shown as Cu-0.3 Sn in Table 1) is 0.46, the work hardening coefficient of SUS304 ( stainless steel in Table 1 ) is 0.42, the work hardening coefficient of pure aluminum (99.99 wt% Al) (aluminum in Table 1) is 0.25, work hardening of steel The coefficient is 0.2.

The elongation of the wire (elementary wire) used for the center line and the outer layer wire is a value measured by a method defined in JIS Z 2241.
The breaking load of the compression twisted wire conductor was measured by a method defined in JIS Z 2241.
For bending resistance, the test conditions for the bending test were 100 g applied load and 5 mm bending R. Further, if the load at break was 60 N or more and the bending resistance was 400 or more, it was judged as acceptable. As a result, it can be seen that the compressed stranded conductor 2 obtained from the production method of the present invention is excellent in bending resistance and tensile strength (load at break / cross-sectional area).
Moreover, since it is not necessary to perform a heat treatment step after the stranded wire, by continuously covering the insulating layer 3, the insulated wire 4 having excellent bending resistance and tensile strength can be obtained. Such an insulated wire 4 is suitable for a wire harness used for automotive applications.

DESCRIPTION OF SYMBOLS 1 Stranded wire 2 Compression strand wire conductor 3 Insulation layer 4 Electric wire (insulated wire)
13 Insulating layer D ₀ Outer diameter of stranded wire before diameter reduction D ₁ Outer diameter of compressed stranded conductor after diameter reduction C ₁ center line C ₅ outer layer wire n ₀ Work hardening coefficient of center line n ₁ outer layer Work hardening coefficient of wire

Claims (3)

Six outer layer wires (C ₅ ) are concentrically twisted on the outer periphery of the center line (C ₁ ) to produce a twisted wire (1), and the twisted wire (1) is further reduced in diameter to be compressed and twisted. A manufacturing method for a wire conductor (2),
The center line (C ₁ ) is made of pure aluminum with a purity of 99.99 wt% or more, and the outer layer wire (C ₅ ) is made of pure copper with a purity of 99.99 wt% or more. The work hardening coefficient of the outer layer wire (C ₅ ) is , Set larger than the work hardening coefficient of the center line (C ₁ ),
And, the diameter reduction processing, the outer diameter of the diameter reduction before the stranded wire (1) (D _0), the outer diameter of the diameter reduction after the compression stranded conductor (2) (D ₁₎ and the The ratio (D ₁ / D ₀ ) is 0.88 to 0.98. A compression stranded conductor produced by the method for producing a compression stranded conductor according to claim 1 . An insulated wire comprising an insulating layer (3) made of an insulating material not containing a halogen element on the outer periphery of a compressed stranded wire conductor produced by the method for producing a compressed stranded wire conductor according to claim 1 .

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