JPH0664938B2 - Flexible and vibration-resistant flexible conductor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a flexible conductor having a large current capacity and excellent bending resistance and vibration resistance.

[Problems to be Solved by Conventional Techniques] For example, a lead wire for power supply of a spot welding machine using an industrial robot is shocked (electrodynamically) due to an extremely large current being applied each time welding is performed. Vibration occurs. Also, the lead wire is swung around each time the robot is operated and repeatedly bent. The lead wire thus used is thus a flexible conductor.

This flexible conductor is usually made by collectively twisting strands of annealed copper wire, concentrically twisting this collective twisted wire into a composite twisted wire (child twist), and further twisting this composite twisted wire into a multiple composite twisted wire. It is composed of lines, and has a sectional structure as shown in FIG. 4, for example.

When the usage of the flexible conductor is observed, the strands of the composite multi-strand wire are rubbed at the portions in contact with each other during repeated bending and impact, and wear breakage occurs. When a part of the wire breaks, the resistance of the conductor increases, the part is overheated, and the wire breaks more easily, which repeats a vicious circle and the wire breaks.

This disconnection is most noticeable at the portion where the outermost layer twisted (2c ′) and the lower layer twisted (2b ′), which are double-composite twists, contact each other, and more particularly than the outermost layer twisted (2c ′). The child twist (2
The wire breakage in b ') is remarkable. Each child twist (2a ') (2
b ′) (2c ′) strands are made of pure annealed copper wire. According to the durability test of the compound composite stranded wire shown in FIG. 4, the outermost layer twisted layer (2c ′) and the lower layer twisted layer (2b ′) Among them, the breakage of the strands of the assembled stranded wire (1d ′) in the outer layer part was particularly remarkable.

Therefore, as a flexible conductor of this type,
It is desired to improve bending resistance and vibration resistance under heating to prevent the wire breakage.

Therefore, from the above observation results, it is proposed that the outermost layer and the lower layer are twisted in the same twist direction so that the wires in contact with each other do not cross each other (Japanese Utility Model Application No. 63-879).
No. 06), but in this case, the wire breakage is less likely to occur as compared with the conventional product in which the strands cross, but a sufficiently satisfactory effect cannot be obtained.

Therefore, the inventors of the present invention, for the prevention of the above wear disconnection,
Furthermore, in the process of conducting various studies and studies, the friction coefficient is smaller when the dissimilar metal wires are in contact with each other than when the same metal wires are in contact with each other, especially when the pure annealed copper wires are in contact with each other. It has been found that wear disconnection due to rubbing or the like is significantly reduced.

Based on this, the twisting using a pure copper wire and the twisting using a wire of a copper alloy as described above are brought into contact with each other, and bending,
When a wear test was conducted by applying vibration, it was found that the wear resistance was greatly improved.

[Means for Solving the Problems] The present invention has been made based on the above findings, and is in contact with the first-layer child twist, that is, the outer-most child twist, in which the disconnection is most likely to occur in the multiple composite twisted wire. For the lower strand of the twisted strand, we will use a softened wire of the following copper alloy that has good electrical properties and excellent mechanical properties such as heat resistance and bending resistance, so that it can be bent without sacrificing conductivity. The present invention provides a flexible conductor which has improved vibration resistance and is extremely effective in preventing abrasion and breakage of the wire.

That is, the first aspect of the present invention is, in particular, in a flexible conductor in which a composite twisted wire obtained by concentrically twisting a collective twisted wire is used as a child twist, and this child twist is further concentrically twisted to form a double composite twisted wire, and the outermost layer thereof is formed. The element wire of the child twist is a pure annealed copper wire, and Fe, Mg and P are contained in the element wire of the child twist of the lower layer in contact with the child twist of the outermost layer, and the content is Fe: 0.02 to 3% by weight Mg: 0.02 to 3% by weight P: 25 to 80% by weight with respect to the Fe content and 70 to 90% by weight with respect to the Mg content, and is composed of a softening wire of a copper alloy with the balance being copper. .

A second aspect of the present invention was made in consideration of the fact that the strand break of the aggregated twisted wire in the outer layer portion is remarkable among the child twists of the lower layer in contact with the child twist of the outermost layer, and the cost of the copper alloy and the like. In the flexible conductor by the same complex composite stranded wire as described above, the strand of the child twist forming the outermost layer is a pure annealed copper wire,
It is characterized in that the strands of the gathered stranded wire in the outer layer portion of the lower twisted child layer that is in contact with the outermost twisted strand are softened wires of the above copper alloy, and the strands of other gathered twisted wires are pure soft copper wires. It is a thing.

In the copper alloy used in the above invention, the Fe content is 0.02 to
3% by weight means that if it is less than 0.023% by weight, the effects of repeated bending strength, tensile strength and heat resistance will decrease.
On the other hand, if it exceeds 3% by weight, the decrease in conductivity (heat conductivity) becomes large. The Mg content of 0.02 to 3% by weight means that the bending strength is less than 0.02% by weight.
Effects such as tensile strength and heat resistance are reduced, while
This is because if it exceeds 3% by weight, the conductivity is lowered and the castability is also lowered. P content is relative to the Fe content present
Addition of 25-80% by weight is effective for forming fine intermetallic compounds, and 70-90% by weight for Mg content.
Is also effective. When P is added to Fe and Mg in excess of the above upper limit, unreacted P remains and conductivity is lost.

The above-mentioned copper alloy is disclosed in Japanese Patent Application No.
No. 8-198357, which has good electrical conductivity and thermal conductivity as described in the specification, and has excellent heat resistance and mechanical properties such as repeated bending and tensile strength. ing.

[Operation] According to the above-mentioned first flexible conductor of the present invention, the outermost layer of the child-twisted element wire of the composite composite stranded wire is a pure annealed copper wire, and the lower-layer child-twisted element wire in contact with this is described above. By using a copper alloy, dissimilar metal wires are in contact with each other in the contact portion between the outer twist of the outermost layer and the lower twist of the outer layer in which the wear breakage of the strand is remarkable, and therefore, compared with the case of the same metal wire. The coefficient of friction is reduced, the wear resistance is greatly improved, and wear disconnection is extremely unlikely to occur. However, this is a soft wire made of copper alloy that has good electrical conductivity and excellent heat resistance and mechanical properties such as repeated bending and tensile strength for the lower-layer (first layer) twisted strands that are easily broken. Combined with this, the effect of preventing wire wear and wire breakage can be enhanced, and the wire breakage occurrence rate can be greatly reduced.

Further, according to the second aspect of the invention, among the child twists of the lower layer in contact with the child twists of the outermost layer, the strands of the gathered twisted wires in the outer layer portion that are most likely to cause abrasion breakage are the softened wires of the copper alloy, and Since the strands of the assembled stranded wire of are made of pure annealed copper wire, the contact portion between this child twist and the outermost child twist becomes a contact between different metal wires, and like the above, frictional disconnection is unlikely to occur in this part. In addition to the above, dissimilar metal wires also come into contact with each other at the contact portion between the gathered twisted wire in the outer layer portion and the gathered twisted wire in the central portion, and abrasion and disconnection at this contact portion hardly occur. Moreover, since the strands of the assembled stranded wire other than the outer layer portion are pure annealed copper wires, there is no problem in the flexibility of the flexible conductor as a whole.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-sectional structure of a flexible conductor made of a complex composite stranded wire according to the first aspect of the present invention. In the figure, (1) is a set stranded wire in which 26 strands having a diameter of 0.26 mm are set and stranded, (2)
Is a collective twisted wire obtained by concentrically twisting the above seven twisted wires (1). The flexible conductor (3) of the multiple composite twists has one composite twisted wire (2) as the child twist (2a) of the center layer, and six compound twists as the child twist (2b) of the outer first layer. The wire (2) is further concentrically twisted by arranging twelve composite twisted wires (2) as the second layer child twist (2c) on the outer side thereof.

The first layer child twist (2c) and the outermost layer child twist (2b) are concentrically twisted in opposite directions as in the conventional case, and both layer child twists (2c) and (2b) are in the same direction. There may be concentric twists.
In the latter case, the strands of the child strands (2c) and (2b) come into contact with each other along the twisting direction, and the conventional strands are strongly contacted locally like flexible conductors that cross each other and come into contact. Therefore, the effect of preventing wear and disconnection due to contact between different types of metal wires, which will be described later, is further enhanced.

Then, in the flexible conductor having the above structure, the outermost layer child twist (2
Pure annealed copper wire is used for the element wire constituting c), and the element wire constituting the lower layer child twist (2b) in contact with this child twist (2c) contains Fe, Mg and P in the above-mentioned compounding ratios, respectively. A copper alloy, that is, a softening wire described in the specification of Japanese Patent Application No. 58-198357 is used. Therefore, the contact portion between the outermost layer and the child twist (2c) and (2b) of the lower layer becomes contact between different metal wires, and the friction coefficient of this portion is small, so that abrasion disconnection hardly occurs. In the drawings, hatching is shown only in the portion using the softening line of the copper alloy.

The strands that compose the center layer child twist (2a) are connected to the first layer child twist (2b)
Although the copper alloy can be used in the same manner as the above, as a result of a durability test, it is better to use pure annealed copper wire for the strands of the center layer of the child twist (2a) when the center layer and the first layer of the child twist (2a) ( The contact part of 2b) is a contact between dissimilar metal wires, which does not cause abrasion and breakage of the wires, and does not reduce flexibility, and the use of an expensive copper alloy compared to annealed copper wire Since the amount is small, it is preferable in practice.

FIG. 2 shows a sectional structure of a second flexible conductor of the present invention.
Lower layer (first layer) composite stranded wire in contact with the outermost child strand (2c)
Of the twisted wires (2b) according to (2), the strands of the assembled stranded wire (1d) in the outer layer portion where wear breakage is likely to occur are the above-mentioned copper alloy softened wires, and other assembled stranded wires, mainly in the case of the figure Part stranded wire
The element wire of (1e) is a pure annealed copper wire similar to the outermost layer of the twisted wire (2c). In the drawings, hatching is shown only in the portion of the gathered stranded wire using the softened wire of the copper alloy.

In this case as well, since the dissimilar metal wires come into contact with each other at the contact portion between the outermost layer twist (2c) and the lower layer twist (2b), abrasion disconnection is less likely to occur at this portion. Also, the amount of copper alloy used is small.

Regarding the child twist (2a) of the central layer, there are cases where the softening wire of the copper alloy is used and cases where it is pure soft copper wire as in the above.

As in the conventional case, the flexible conductor (3) has the connection terminals (4) fixed to both ends as shown in FIG. 3, and the insulating outer cylinder (5) is covered between the terminals. The cooling water is kept watertight so that it can be circulated, and is used as a lead wire for supplying power to the welding robot.

(Test of Confirmation of Effect) The flexible conductor of the embodiment shown in FIG. 1 and the flexible conductor of the embodiment shown in FIG. 2 and the flexible conductor shown in FIG. 4 (all the wires are pure annealed copper wires). Of the outermost layer (the second layer) and the lower layer (the first layer) of the twisted layers in the same direction as the concentric twisted (A) The concentric twisted product (B) was tested in a welding robot under the same conditions, the durability of the spot welding was compared, and the wear disconnection condition was observed. The results were as follows.

Samples Twisting direction Number of spots Example of Figure 1 A 40 to 500,000 times Same as B 600,000 times or more Example of Figure 2 A 300 to 400,000 times Same as B 500,000 times or more Figure 4 (Conventional product) A Approximately 100,000 times (Comparative example) B 300 to 400,000 times As shown in the above table, the conventional product suffers wear disconnection at about 100,000 spots, and the disconnection rate is 25% at both ends near the connection terminal.
However, in the case of the present invention, each of them can withstand the use of the spot number of 3 to 6 times or more as compared with the conventional product, and the disconnection rate is 10% at both ends.
In particular, when the outermost layer and the lower layer are twisted in the same direction, abrasion breakage is more difficult to occur.

[Advantages of the Invention] As described above, according to the present invention, the bending resistance and the vibration resistance can be remarkably improved as compared with the conventional products without impairing the conductivity, and lead wires for power supply of the welding robot, etc. As a flexible conductor of this type used for, it is possible to prevent wear disconnection for a long period of time and to greatly enhance its durability. Moreover, since the copper alloy is used only for the lower twisted strands that are in contact with the outermost layer, the amount of relatively expensive copper alloy used can be small.
In particular, of the lower-layer twists that are in contact with the outer-most twists, the strands of the outer strands that are most susceptible to wear breakage are the strands of copper alloy softening and the strands of the other strands are pure soft copper. In the case of a wire, the amount of the copper alloy used is further smaller, and the wire can be manufactured and provided at low cost.

[Brief description of drawings]

FIG. 1 is a schematic view of a sectional structure showing an embodiment of a flexible conductor of the present invention, FIG. 2 is a schematic view of a sectional structure showing another example of the present invention, and FIG. FIG. 4 is a plan view showing a use state in which it is connected to a terminal, and FIG. 4 is a schematic view of a cross-sectional structure of a conventional flexible conductor. (1) ... Assembled stranded wire, (1d) ... Assembled stranded wire in outer layer part, (1e) ... Assembled stranded wire in central part, (2) ... Composite stranded wire, (2a) (2b) (2c) ... Each layer Child twist, (3) ... Flexible conductor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Matsui 2-3-1 Iwata-cho, Higashi-Osaka City, Osaka Prefecture Tatsuta Electric Wire Co., Ltd. (56) References: 60-164710 Kai 63-108113 (JP, U) Copper Technology Research Journal Vol. 16, 1977 pp. 165-176 Metal Handbook p. 622

Claims (2)

[Claims] 1. A flexible conductor comprising a composite stranded wire obtained by concentrically twisting a set stranded wire as a child twist, and further concentrically twisting the child twisted wire into a composite composite stranded wire, which is an outermost layer of a child stranded wire. Is a pure annealed copper wire, and the element wire of the lower layer of the twisted wire that is in contact with the outermost layer of the twisted wire is
(a) Copper alloy softening wire, which is characterized by bending resistance,
Vibration resistant flexible conductor. (a) Fe, Mg and P are contained, and the content is Fe: 0.02 to 3% by weight Mg: 0.02 to 3% by weight P: 25 to 80% by weight based on the Fe content, and Mg
A copper alloy with 70 to 90% by weight of the content and the balance being copper. 2. A flexible conductor comprising a composite twisted wire obtained by concentrically twisting a collective twisted wire as a child twist, and further concentrically twisting the child twisted wire into a composite twisted wire, which is an outermost layer of a child twisted wire. Is a pure annealed copper wire, and the strands of the aggregated stranded wire in the outer layer part of the lower layer of the twisted layer that is in contact with the outermost layer of the twisted strand are the softened wires of the copper alloy in (a) below, and the other strands of the aggregated strand are pure. A flexible conductor resistant to bending and vibration, characterized by using an annealed copper wire. (a) Fe, Mg and P are contained, and the content is Fe: 0.02 to 3% by weight Mg: 0.02 to 3% by weight P: 25 to 80% by weight based on the Fe content, and Mg
A copper alloy with 70 to 90% by weight of the content and the balance being copper.