JP3108525B2 - Transfer cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving cable which is mounted on a robot or the like and is used by being moved together with the robot.

[0002]

2. Description of the Related Art Examples of this type of cable include a generally used moving cable, a primary cable for a gun with a transformer of a spot welding machine, a water-cooled cable for a portable spot welding machine, and an air-cooled cable for a multi-welding machine.
Since these cables are used under extremely severe use conditions, they have a problem that they do not last long and are disconnected at an early stage.

That is, in a spot welding machine 20 as shown in FIG. 4, as a welding gun 21 is operated, a connection with a transformer 23 among welding cables (one kind of moving cable) 22 is performed. The end 22a is locally sharply bent. Since the welding gun 21 repeats severe movement while bending the welding cable 22, there is a possibility that the connection end portion 22a of the welding cable 22 is disconnected in a short time (early disconnection).

As shown in FIG. 5, a transformer 24 is disposed at a position distant from the welding gun 25, and power is supplied to the welding gun 25 via the kickless cable 26 and the auxiliary cables 27a and 27b sequentially. Also in the machine 28, there is a possibility that the connection ends 29a and 29b of the auxiliary cables 27a and 27b are disconnected in a short period of time as in the case of the spot welding machine 20 described above. That is, in the spot welding machine 28, since the kickless cable 26 is a unit which is set in a case such as a hose while insulating a reciprocating cable having a different current direction, the kickless cable 26 The electric repulsive force generated between the reciprocating cables stops in the hose, and no kick occurs as a single kickless cable. However, in the case of the non-kickless auxiliary cables 27a and 27b, large currents having different directions flow when energized, and a strong magnetic field is generated around them, and this magnetic field repels the two auxiliary cables 27a and 27b. In addition, the alternating current causes vibration, which causes local bending and, consequently, premature disconnection.

Therefore, the welding cable 22 as described above is used.
Alternatively, in order to prevent disconnection of the auxiliary cables 27a and 27b, a proposal is made to cover the connection end of the cable with a protective net, thereby relieving the bending of the connection end and reducing the disconnection (Japanese Patent Laid-Open No. 1-249275). See).

The operation and effect of the above-described protection network are as follows. That is, as shown in FIG.
If the connection end portion 30a of 0 is connected to the box portion 31 as it is, stress concentrates on the connection portion between the cable 30 and the box portion 31 (the root portion of the cable 30), but as shown in FIG. When the protection net 32 is put on the connection end portion 30a as described above, the bending at the root of the cable 30 is relieved, and the stress is dispersed throughout the cable 30, so that the early disconnection of the cable 30 is prevented.

[0007]

However, in the cable proposed in the prior art, welding spatter (deposits) adheres to the protection net (weld spatter adheres to stainless steel, which is the material of the protection net). There is a problem that the life of the protection network is greatly reduced due to this.

Further, before the cable 30 is broken, the protection net 32 is rubbed against the outer sheath (sheath or jumper hose) of the cable 30 or the power supply conductor, or the protection net 32 is rubbed between the wires of the protection net 32. May be worn and damaged. Alternatively, wire stress may occur due to stress concentration due to bending, resulting in breakage. When the strands of the protection net 32 are broken as shown in FIG. 6C, the stress caused by bending concentrates on the broken portion, and the life of the cable 30 is shortened at an accelerated pace. Therefore, such a situation is the worst case for the cable.

Further, as shown in FIG. 7, when the strand 33 made of stainless steel constituting the protection net is broken, the broken strand 33 of stainless steel is broken at the breakage point P as shown in FIG. It penetrates the sheath 34 of the cable 30 and comes into contact with the power supply conductor 35 to cause a ground fault (ground fault current I
g) or a cable failure may be caused.

As described above, in the conventional cable 30,
The provision of the protection net 32 for preventing disconnection may cause an accelerated reduction in the life of the cable 30 and secondary adverse effects such as a ground fault.

The present invention has been made to solve such various problems, and an object of the present invention is to prevent the adhesion of welding spatter to a protection net and extend the life of the protection net. In addition, to prevent the abrasion caused by the rubbing between the protective net and the cable sheath or the power supply conductor, to prevent breakage of the protection net or the cable, and to ground fault accident due to contact with the power supply conductor due to breakage of the strand of the protection net itself. It is an object of the present invention to provide a moving cable which can prevent such a problem.

[0012]

In order to achieve the above-mentioned object, according to the present invention, a cylindrical protective net coated with a heat-resistant resin material is fitted to a cable connection end, and this portion is connected to the protective net. It is covered.

[0013]

Since the surface of the protective net is coated with a heat-resistant resin material, the presence of the heat-resistant resin coating prevents welding spatter from directly adhering to the strands of the protective net. The life of the protection net is extended, and the life of the welding cable is extended. Moreover, since a heat-resistant resin material (coating) is interposed between the strands of the protection net and the cable sheath or the power supply conductor and between the strands, no friction occurs between them. In addition, it is possible to prevent a situation in which the element wire is broken due to the rubbing and the protection net is damaged. In addition, since the broken stainless steel wire of the protection net itself is coated, the wire does not come out of the coating, so that there is no contact with the power supply conductor and a ground fault accident or the like is prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a spot welding machine (welding robot) 2 having a welding cable (a kind of moving cable) 1a, 1b according to the present invention as a part of a secondary cable. The spot welding machine 2 includes a welding gun 4 at the tip of an arm 3, and the arm 3 and the welding gun 4 are automatically operated by a controller (not shown).

The transformer 5 is fixedly arranged separately from the arm 3, and power is supplied from the transformer 5 to the welding gun 4 via the secondary cable 6. The above-described secondary cable 6 includes the two welding cables (auxiliary cables) 1a and 1b described above and one kickless cable 7, and these welding cables 1a and 1b.
1b is connected in parallel between the kickless cable 7 and the welding gun 4.

The kickless cable 7 is a unit in which cables having different current directions are insulated and set in a rubber hose or the like to form a unit.
Reference numerals a and 1b denote cables that allow current to flow only in one direction. Therefore, when the secondary cable 6 is energized, the electric force is not expressed as a kick of the kickless cable 7, but the two welding cables 1 a and 1 b have current directions opposite to each other. A large repulsive force is generated between each other. In conjunction with this, the welding cables 1a and 1b are severely swung together with the arm 3 during the spot welding operation.
a, 1b, in particular, both ends thereof, ie, connection ends A, B
Tend to be sharply bent.

Therefore, in order to cope with such a sharp bend, the outer periphery of the connection end portion A of the welding cables 1a and 1b (on the outer periphery of the power supply conductor, or when the power supply conductor is covered with a jumper hose, this is not necessary). A cylindrical protection net 9 is fitted on the outer periphery of the jumper hose), and the connection end A is covered with the protection net 9. More specifically, as shown in FIGS. 2 and 3, this protection network 9
A unit stranded wire 11 composed of a plurality of stainless wires 10 is formed in a tubular shape by oblique weaving, and each unit stranded wire 11 is made of a heat-resistant resin material (for example, a 4-fluorocarbon resin having excellent spatter resistance). Coating 1 consisting of ethylene resin)
2 is given. Therefore, the protective net 9 is completely covered with the coating 12. As shown in FIG. 2, the protection net 9 having such a structure is connected to the connection ends A of the welding cables 1a and 1b, that is, the outer periphery of the end of the jumper hose 14 that covers the power supply conductor 13 in this example. It is fitted to.

Thus, the terminals 15 attached to both ends of the power supply conductor 13 are electrically connected to the kickless cable 7 and the welding gun 4, respectively, whereby the welding cables 1a and 1b are welded to the kickless cable 7. Gun 4
Installed between.

The welding cables 1a, 1 having such a configuration are described.
According to b, since the protection net 9 is covered, the bending of the connection end portions (root portions) A of the welding cables 1a and 1b is relieved, thereby preventing early disconnection, and a unit constituting the protection net 9. By applying the coating 12 to the stranded wire 11, welding spatter can be prevented from adhering to the unit stranded wire 11, and a reduction in the life of the protection net 9 due to the welding spatter can be prevented. Further, the presence of the coating 12 does not cause friction between the protection net 9 and the jumper hose 14 or the power supply conductor 13 and between the unit twisted wires 11 of the protection net 9, so that these frictions are not caused. This can prevent the protection net 9 from being damaged, and the occurrence of accidents and the like caused by the piercing of the broken stainless steel wire 10 into the power supply conductor.

As described above, one embodiment of the present invention has been described.
The present invention is not limited to the embodiments described above, and various modifications and changes can be made based on the technical idea of the present invention. For example, the coating 12 applied to the protective net 9 is not limited to ethylene tetrafluoride resin, and other types of heat-resistant resin can be applied. Further, it goes without saying that the present invention is not limited to the welding cables 1a and 1b used in the spot welding machine, but can be applied to a moving cable used in other types of robots and the like.

[0022]

As described above, according to the present invention, a cylindrical protective net formed by coating a heat-resistant resin material is fitted to the connection end of a cable so as to cover this portion. Because of this, the presence of the coating can prevent the welding spatter from adhering to the strands constituting the protection net and shorten the life, and can prolong the life of the protection net. Furthermore, the protection net does not rub against the cable sheath or the power supply conductor when the cable is bent, and the wires of the protection net do not rub against each other, and the wires are worn or broken due to the rubbing. Consequently, damage to the protection net can be prevented. As a result, it is possible to prevent the accelerated acceleration of the disconnection of the cable caused by the broken line of the protection net, and to prevent the occurrence of a ground fault or the like due to the piercing of the broken wire into the power supply conductor by coating the stainless wire.

[Brief description of the drawings]

FIG. 1 is a perspective view of a spot welder provided with a welding cable according to the present invention.

FIG. 2 is a perspective view of a connection end of the welding cable according to the present invention.

FIG. 3 is a perspective view showing a unit twisted wire of the protection net broken away.

FIG. 4 is a side view of a conventional spot welding machine having a welding cable.

FIG. 5 is a side view of another spot welding machine provided with a conventional welding cable.

FIG. 6A is a plan view showing a case where a protection net is not fitted to a connection end of a welding cable, and FIG. 6B is a view showing a case where a protection net is fitted to the connection end. Plan view,
(C) is a top view which shows the case where the protection net fitted to the said connection end part was broken.

FIG. 7 is a perspective view showing a state in which a protection net fitted to the connection end of the welding cable is broken.

FIG. 8 is an explanatory diagram conceptually showing a state in which a broken ground wire of the protection net pierces a power supply conductor and causes a ground fault.

[Explanation of symbols]

 1a, 1b Welding cable 2 Spot welding machine (welding robot) 9 Protection net 10 Stainless wire 12 Coating 13 Power supply conductor 14 Jumper hose A Connection end

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazutaka Fukushima 1-15-13 Nishiki, Naka-ku, Nagoya City, Aichi Prefecture Japan Flex Co., Ltd. (72) Inventor Kenichi Fukuya 1-15-, Nishiki, Naka-ku, Nagoya City, Aichi Prefecture 13 Japan Flex Co., Ltd. (56) References JP-A-1-249275 (JP, A) JP-A-2-118683 (JP, U) JP-A-5-1884872 (JP, U) (58) Fields investigated ( Int.Cl. ⁷ , DB name) H01B 7/24 B23K 11/11 530 B23K 11/24 358 H01B 7/00 306

Claims (1)

(57) [Claims] 1. A transfer cable, wherein a cylindrical protection net coated with a heat-resistant resin material is fitted to a cable connection end to cover this portion.