JPH02207407A - Bending-and-oscillation-resistant flexible conductor - Google Patents

Abstract

PURPOSE:To improve wear resistance by having stranded element wires constituting the outermost layer formed into pure soft copper wires and stranded element wire constituting the lower layer in contact therewith formed into softened wires of preset copper alloy. CONSTITUTION:A flexible conductor 3 comprises collective stranded wires 1 for which element wires are collectively stranded and complex stranded wires 2 for which the collective stranded wires are stranded in a concentric manner. The complex-stranded flexible conductor 3 is stranded in a concentric manner by arranging one complex stranded wire 2 as a stranded wire 2a for a center layer, six complex wires 2 as stranded wires 2b for the first layer of the next outside and 12 complex stranded wires 2 as stranded wires 2c for the second layer of the next outside. For the element wires constituting the stranded wires 2c for the outermost layer, pure soft copper is used, and for the element wires constituting the stranded wires 2b for the lower layer in contact therewith, copper alloy is used which contains Zr and Sn, with the content by wt. of 0.05-0.2% and 0.05-0.5% respectively, and copper for the rest.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides a flexible conductor having a large current capacity and excellent bending resistance and salt movement resistance.

[Conventional technology and problems to be solved] For example, in the power supply lead wire of a spot welding machine using an industrial robot, an extremely large current is passed through each time welding, and an impact (electrodynamic) Vibration occurs. Furthermore, each time the robot operates, the lead wire is twisted and bent repeatedly. The leads used in this manner are therefore flexible conductors.

This flexible conductor is usually made by twisting together strands of mild steel wire, concentrically twisting the assembled strands to make a compound strand (child twist), and further concentrically twisting the compound strand to make a compound strand. It consists of a wire, and has a cross-sectional structure as shown in FIG. 4, for example.

When observing the use of the above flexible conductor, do you notice repeated bending?
#J The strands of the compound stranded wire are rubbed at the parts where they touch each other on the jumper, causing wear and breakage.

When a part of the strands breaks, the resistance of the conductor increases, and that part overheats, making it even more likely to break, and the vicious cycle repeats, causing the wire to break.

This disconnection is caused by the outermost child twist (2C') of the compound twist.
This is most noticeable at the part where the outermost child twist (2b') and the child twist (2b') in the lower layer are in contact with each other, and the wire breakage is particularly noticeable in the child twist (2b') in the lower layer than in the child twist (2c') in the outermost layer. According to the durability test of the composite stranded wire shown in Fig. 4, in which pure annealed copper wire was used as the wire of each child twist (2a') (2b') (2c'), it was found that the wires in contact with the outermost layer child twist (2c') Among the child twists (2b') in the lower layer, the breakage of the strands of the collective strands (ld') in the outer layer portion was particularly remarkable.

Therefore, when using this type of flexible conductor,
It is desired to improve the bending resistance and vibration resistance under heating to prevent the above-mentioned wire breakage.

Therefore, based on the above observation results, it was proposed that the twisting directions of the outermost layer and the lower layer are the same so that the wires touching each other do not cross.
No. 06), although in this case wire breakage was less likely to occur compared to conventional products in which the strands crossed, a fully satisfactory effect could not be obtained.

Therefore, the present inventors aimed to prevent the above-mentioned wear-out and disconnection.
Furthermore, in the process of researching and examining various types of wires, we found that the friction coefficient is smaller when wires of different metals are in contact with each other than when wires of the same metal, especially pure annealed copper wires, are in contact with each other. It has been found that the occurrence of wear and disconnection due to rubbing etc. is significantly reduced.

Based on this, by bringing the child twist using pure copper wire into contact with the child twist using separately mentioned copper alloy wire, bending,
When a wear test was conducted by applying vibrations, 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 the present invention is based on the above-mentioned findings. We decided to use a softened wire made of the following copper alloy, which has good electrical conductivity and excellent mechanical properties such as heat resistance and bending resistance, for the lower layer child-twisted wires. The present invention provides a flexible conductor that has improved vibration resistance and is extremely effective in preventing wire breakage due to wear and tear.

That is, the first aspect of the present invention is, in particular, in a flexible conductor in which a composite stranded wire obtained by concentrically twisting agglomerated stranded wires is used as a child twist, and the child twist is further concentrically twisted to form a compound compound strand, the outermost layer thereof is configured. The strands of the child twist are made of pure annealed copper wire, and the strands of the child twist of the lower layer in contact with the child twist of the outermost layer contain Zr and Sn, and the content thereof is Zr: 0.005 to 0.2 weight, respectively. %S
n: 0.05 to 0.5% by weight, and the remainder is copper, which is constructed using a softened copper alloy wire.

The second aspect of the present invention is that the wire breakage of the collective stranded wires in the outer layer is remarkable among the lower layer child twists in contact with the outermost layer child twists, and the cost of the copper alloy is taken into consideration. In a flexible conductor made of the same compound twisted wire as described above, the wires of the child twist constituting the outermost layer are pure annealed copper wire, and the outer layer portion of the child twist of the lower layer in contact with the child twist of the outermost layer is made of pure annealed copper wire. It is characterized in that the strands of the assembled stranded wires are made of the above-mentioned softened copper alloy wires, and the other strands of the assembled stranded wires are made of pure annealed copper wires.

In the copper alloy used in the above invention, the Zr content is 0.0
05 to 0.2% by weight is because o, oos without grooves will have less effect on cyclic bending strength, tensile strength, heat resistance, etc., whereas if it exceeds 0.2% by weight, the electrical conductivity (thermal conductivity) will decrease. The reason for this is that the decline in performance (sexuality) increases. The reason why the Sn content is set to 0.05 to 0.5% by weight is that if it is less than 0.05i1% by weight, the effects of cyclic bending strength, tensile strength, heat resistance, etc. will decrease, while if it exceeds 0.5% by weight, This is because conductivity decreases and castability also decreases.

[Function] According to the first flexible conductor of the present invention described above, the outermost layer of the twisted wires of the composite wire is made of pure annealed copper wire, and the lower layer of the twisted wires in contact therewith are made of the above-mentioned wires. By using a copper alloy made of copper alloy, dissimilar metal wires come into contact with each other in the contact area between the outermost layer of child twist and the child twist of the lower layer, where wear and breakage of the strands is noticeable. The coefficient of friction is reduced, the wear resistance is greatly improved, and wear-out breaks are extremely difficult to occur. Coupled with the use of copper alloy softened wire, which has good mechanical properties such as heat resistance, repeated bending, and tensile strength, it increases the effect of preventing wire breakage due to wear and tear, and reduces the incidence of wire breakage. can be significantly reduced.

Further, according to the second invention, among the child twists in the lower layer that are in contact with the child twists in the outermost layer, the strands of the collective stranded wire in the outer layer portion where wear and breakage is most likely to occur are the softened wires of the copper alloy, and Since the strands of the assembled stranded wire are made of pure annealed copper wire, the contact area between this child twist and the child twist in the outermost layer is a contact between different metal wires, and as mentioned above, frictional disconnection is unlikely to occur at this part. In addition, dissimilar metal wires come into contact with each other at the contact portion between the stranded wires in the outer layer portion and the stranded wires in the central portion, making it difficult for wear and wire breakage to occur at this contact portion.

Moreover, since the strands of the stranded wires other than the outer layer portion are made of pure annealed copper wire, there is no problem with the flexibility of the entire flexible conductor.

[Example code] Next, one embodiment of the present invention will be described based on the drawings.

Figure 1 shows the cross-sectional structure of a flexible conductor made of composite stranded wires according to the first invention. Stranded wire, (
2) is a composite stranded wire in which seven of the above-mentioned aggregated strands are concentrically twisted.The flexible conductor (3) with multiple composite strands has one composite stranded wire (2) connected to the child 1!( of the center layer). 2a), and the first outside
Six composite strands (2) are arranged as child twists (2b) of the layer, and 12 composite strands (2) are arranged as child twists (2c) of the second layer on the outside, respectively, and twisted concentrically. ing.

In addition to the case where the child twist (2C) of the first layer and the child twist (2b) of the outermost layer are concentrically twisted in opposite directions as in the conventional case,
The child twists (2c) and (2b) of both layers may be concentrically twisted in the same direction. In the latter case, the strands of the child twists (2c) and (2b) come into contact with each other along the twisting direction, and the strands do not make strong local contact like in a conventional flexible conductor where the strands cross and touch each other. Therefore, the effect of preventing wire breakage due to wear and tear due to contact between dissimilar metal wires, which will be described later, becomes even greater.

In the flexible conductor having the above structure, the outermost layer child twist (
This child! (2
The copper alloy containing Zr and Sn in the above-mentioned mixing ratios, that is, the mixing ratios of each element is Zr:
It is constructed using a copper alloy containing O: 1% by weight and Sn: 0.1% by weight. Therefore, the contact portion between the outermost layer and the child twists (2cX2b) of the lower layer is the contact between different metal wires, and the coefficient of friction at this portion is small, making it difficult for wire breakage to occur due to wear. Note that in the drawings, only the portions using the softened wire of the copper alloy are shown with hatching.

Child 1 of the first layer, which is a tight wire that constitutes the child twist (2λ) of the center layer
Although it is possible to use the above-mentioned copper alloy as in 11(2b), as a result of the durability test, it is better to use pure annealed copper wire for the strands of the child twist (2a) in the center layer and the child twist in the first layer. (2a) (
The contact part in 2b) is a contact between dissimilar metal wires, which reduces wear and breakage of the strands, does not reduce flexibility, and uses copper alloy, which is more expensive than annealed copper wires. Since the amount is smaller, it is more suitable in practice.

FIG. 2 shows a cross-sectional structure of a second flexible conductor of the present invention, and in a flexible conductor made of a compound twisted wire similar to the above,
Of the child twists (2b) of the composite strands (2) of the lower layer (first layer) that are in contact with the child twists 2C) of the outermost layer, the strands of the collective strands (1d) in the outer layer portion where wear and breakage easily occur are as described above. The other clustered stranded wires, in the case of the figure, the strands of the clustered stranded wires (le) in the center part are pure annealed copper wires similar to the child twisted wires (2C) in the outermost layer.

In the drawings, only the part of the stranded wire using the softened copper alloy wire is shown with hatching.

Again, the outermost child! In the contact area between (2C) and the child twist (2b) in the lower layer, dissimilar metal wires come into contact with each other, so wear and breakage is less likely to occur in this area, and the amount of copper alloy used is also small. .

Regarding the child twist (2a) in the center layer, there are cases where the wire is made of the above-mentioned softened copper alloy as described above, and cases where it is made of pure annealed copper wire.

The above flexible conductor (3) has connection terminals (4) fixed to both ends as shown in the conventional example, and an insulating outer t1M (5) is placed between both terminals. It is held watertight to allow cooling water to flow through it, and is used as lead wires for power supply to welding robots.

(Test to confirm effectiveness) The flexible conductor of the example shown in Fig. 1 above, the flexible conductor of the example shown in Fig. 2, and the flexible conductor shown in Fig. 4 (all strands are pure annealed copper wire) (A) which is concentrically twisted with the twist direction of the outermost layer (No. 2111) and the child twist of the lower layer (Fig. 1) in the intersecting direction.
(B), which was concentrically twisted in the same direction, was tested on a welding robot under the same conditions, compared with the number of spot welding cycles, and observed the state of wear and breakage.The following results were obtained. became.

Sample Twisting direction Spot count Example of Figure 1 A 350,000 to 450,000 times 8
550,000 times or more Example of Figure 2 A 250,000 to 350,000 times Same 8
450,000 times or more Fig. 4 (Conventional product) A Approximately 100,000 times Fig. 4 (Comparative example) B 260,000 to 350,000 times As shown in the table above, the conventional product wears and breaks at about 100,000 spots. The rate was 26% to 35% at both ends near the connection terminal, but in the case of the present invention, it was 3 to 6% lower than the conventional product.
Can withstand twice or more spot use,
Moreover, the wire breakage rate was 10% or less even at both ends, and especially when the outermost layer and the child twists in the lower layer were twisted in the same direction, wear breakage became even less likely to occur.

[Effects of the Invention] As described above, according to the present invention, the bending resistance and vibration resistance characteristics can be significantly improved compared to conventional products without impairing conductivity, and lead wires for power supply of welding robots, etc. As this type of flexible conductor used in , it is possible to prevent wear and disconnection over a long period of time, greatly increasing its durability. Moreover, since the copper alloy is used only for the child twisted wires in the lower layer that are in contact with the outermost layer, the amount of relatively expensive copper alloy used can be reduced. In particular, among the lower layer child twists that are in contact with the child twists in the outermost layer, the strands of the collective stranded wire in the outer layer part where wear and breakage are most likely to occur are made of softened copper alloy wire, and the strands of the collective strand wire of the pond are made of pure annealed copper wire. In this case, the amount of the copper alloy used can be further reduced, and it can be manufactured and provided at low cost.

FIG. 2 is a schematic diagram of a cross-sectional structure of a flexible conductor.

(1)...Collected strands, (ld)...Collected strands in the outer layer (1e)...Collected strands in the center, (2)...
Composite twisted wire, (2a) (2b) (2c)... child twist of each layer, (3)... flexible conductor.

Claims (2)

[Claims] (1) In a flexible conductor in which a composite stranded wire is made by concentrically twisting a set of stranded wires, and this child strand is further concentrically twisted to form a composite stranded wire, the strands of the child strands constituting the outermost layer are pure. Made of soft copper wire,
A bend-resistant and vibration-resistant flexible conductor characterized in that the strands of the lower layer of child twists in contact with the child twists of the outermost layer are softened copper alloy wires as described in (a) below. (a) A copper alloy containing Zr and Sn, the contents of which are Zr: 0.005-0.2% by weight, Sn: 0.05-0.5% by weight, and the balance is copper. (2) In a flexible conductor in which a composite stranded wire is made by concentrically twisting a set of stranded wires, and this child strand is further concentrically twisted to form a composite stranded wire, the strands of the child strands constituting the outermost layer are pure. Made of soft copper wire,
The strands of the aggregated stranded wire in the outer layer portion of the lower layer of child twists that are in contact with the outermost layer of child twists are made of the softened copper alloy wire shown in (a) below, and the strands of the other aggregated stranded wires are made of pure annealed copper wire. Features a flexible conductor that is resistant to bending and vibration. (a) A copper alloy containing Zr and Sn, the contents of which are Zr: 0.005-0.2% by weight, Sn: 0.05-0.5% by weight, and the balance is copper.