JP2881074B2 - Water cooling 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 water-cooled cable, and more particularly, to a flexible, high-frequency, high-current water-cooled cable used in a high-frequency induction heating furnace or the like.

[0002]

2. Description of the Related Art In general, a high frequency induction heating furnace generally has
A low voltage, large current of 100 to tens of thousands of amps is supplied at a frequency of 0 to several hundred kHz. For this reason, the cable used to connect the power supply of the high-frequency induction heating furnace and the heating coil is generally a water-cooled cable in which cooling water flows inside the cable to remove heat generated from the cable and has flexibility. ing. One example of a water-cooled cable used in such a high-frequency induction heating furnace is, conventionally, a wire-shaped cylindrical conductor supported by a spring, covered with a rubber tube, so that cooling water flows inside the wire-shaped conductor. Had become. In such a cable, the conductor is a single wire,
In the high-frequency induction heating furnace, two cables were connected from a power supply, and one was used for a current forward path and one was used for a current return path. This water-cooled cable is flexible because the wire-like conductor supported by the spring is covered with a rubber tube, so that the induction heating furnace needs to move the heating coil. It was suitable for use.

[0003]

However, if the heating coil of the induction heating furnace and the power supply are connected by these two conventional water-cooled cables, the potential drops by the water-cooled cables, especially when a high-frequency, large current flows. Rapidly increases, the supply voltage applied to both ends of the heating coil decreases, and the heat loss of the cable rapidly increases. In addition, there is a problem that vibrations are generated in the two cables due to interference of the electromagnetic field between the two reciprocating cables.

[0004] In view of the problems of the prior art, the present invention can be used in an induction heating furnace to supply electric power to a heating coil with a small potential drop against a high-frequency large current, that is, efficiently. It is another object of the present invention to provide a water-cooled cable that does not dissipate an electromagnetic field to the outside.

[0005]

SUMMARY OF THE INVENTION A water-cooled cable according to the present invention is provided with an inner tube made of a wire-like conductor or a bellows-like metal conductor covered by an insulating tube and supported by a spring. An outer cylinder made of a wire conductor or a bellows-shaped metal conductor that is coaxially arranged and covered with an insulator and supported by a spring, and is cooled between the inner cylinder and the inner cylinder and the outer cylinder. It is characterized by the fact that water circulates.

[0006]

Since the line-shaped conductor covered by the insulator and supported by the spring is coaxially arranged, the current flowing through the inner cylinder and the outer cylinder flows uniformly over the entire circumference. Conventionally, when a high-frequency large current flows through two parallel conductors, the current concentrates inside the two parallel conductors due to mutual electromagnetic field interference.
It is considered that the resistance and the inductance of the cable suddenly increased, and the potential drop increased rapidly. Therefore, by arranging the conductors of the inner cylinder and the outer cylinder of the present invention coaxially, the uneven concentration of the current to the negative portion is eliminated, the resistance and the inductance of the cable are greatly reduced, and the potential of the cable is reduced. The drop is greatly reduced, and power can be efficiently supplied to the heating coil. Furthermore, by arranging the conductors of the inner cylinder and the outer cylinder coaxially, it is possible to prevent the electromagnetic field from diffusing to the outside of the cable. Therefore, problems such as vibration of the cable caused by interference of the electromagnetic fields of the two parallel conductors can be prevented, and the stability of the cable can be improved.

[0007]

FIG. 1 is a sectional view of a water-cooled cable according to an embodiment of the present invention. This cable comprises an inner tube 8 and an outer tube 9 in which conductors are arranged coaxially. Cable inner tube 8
Is constituted by a spirally wound spring 2 made of phosphor bronze or the like, a wire-shaped conductor 1 supported by the spring 2, and an insulating tube 3 covering the conductor portion. Similarly, the outer sleeve 8 of the cable is a spirally wound spring 6 made of phosphor bronze or the like, the wire-shaped conductor 1 supported by the spring 6, and an insulating coating 7 made of rubber or the like to be the outer sheath of the cable. It is composed of

Each of the inner cylinder 8 and the outer cylinder 9 has a structure in which a net-shaped conductor supported by a spring is covered with an insulator such as rubber, so that each has flexibility.
Further, since the inside of the inner cylinder 8 is hollow, it becomes a cooling water passage 15 through which cooling water flows. Since the outer cylinder 9 is disposed coaxially with the inner cylinder 8 and has a hollow portion (gap) through which cooling water flows, the hollow portion between the outer cylinder 9 and the inner cylinder 8 becomes a cooling water passage 16.

The flanges 11, 12, 13, and 14 are connected to terminals 21 and 22 formed of copper hollow pipes, and are electrically connected to the inner tube 8 and the outer tube 9 of the cable.
Cooling water channel 1 in the cable as well as an electric power flange
It is mechanically connected to 5, 16 to form a cooling water flange. Therefore, for example, the cooling water flowing from the flange 11 passes through the hollow portion of the terminal 21, passes through the cooling water passage 15 inside the inner cylinder 8, takes heat from the internal conductor 1, and passes through the hollow portion of the terminal 21 to the flange 13. It enters the heating coil.
After cooling the heating coil, the cooling water enters the cable through the flange 14, passes through the hollow portion in the terminal 22, passes through the cooling water passage 16 in the hollow portion (gap) between the inner cylinder and the outer cylinder,
It mainly takes heat from the conductor 5 of the outer cylinder and flows out of the flange 12 to the power supply side.

Electrically, the flanges 11 and 13 are
The flanges 12 and 14 are connected to the conductor 5 of the outer cylinder 9 via the terminal 22. The connection between the terminals 21 and 22 and the conductors of the inner cylinder 8 and the outer cylinder 9 is made of a copper hollow of the terminals 21 and 22 in which the conductors 1 and 5 which are wire-shaped conductors are connected to the flanges 11, 12, 13 and 14. Sufficient electrical and mechanical strength can be obtained by caulking the pipe. The copper pipe of the terminal 22 connected to the conductor 5 of the outer cylinder 9 and the copper pipe of the terminal 22 connected to the conductor 1 of the inner cylinder 8 are made of insulators 19 and 2 such as Teflon.
0 is electrically insulated and mechanically connected and fixed.

Next, the operation of the water-cooled cable will be described. With the flanges 11 and 12 on the power supply side,
14 is connected and fixed to the heating coil. When a high-frequency high current is supplied to the heating coil from the power supply side, the current flows intensively outside the inner conductor 1 and inside the outer conductor 5 due to the skin effect, but the inner conductor 1 of the inner tube 8 and the outer tube 9 Are arranged coaxially with the outer conductor 5, so that the current distribution of both conductors becomes uniform in the circumferential direction. Therefore, the uneven concentration of current caused by the so-called proximity effect, which is a problem of the prior art, which occurs between two parallel conductors, is eliminated, and the resistance and inductance of the cable are greatly reduced. Therefore, the potential drop in the cable is conventionally 10% of the supply voltage of the power supply, for example.
By reducing the value from 20% to several percent or less, high-frequency power can be efficiently supplied to the heating coil. Further, since the resistance of the cable is reduced and the calorific value is reduced, the temperature rise of the cooling water is reduced, and the cooling water can be effectively used for cooling the heating coil.
In addition, since the conductor is arranged coaxially by the inner tube 8 and the outer tube 9, no electromagnetic field is radiated outside the cable. Therefore, problems such as vibration of the conductor caused by interference of the electromagnetic field between the two parallel conductors in the related art can be solved, and furthermore, the problem that the electromagnetic field is radiated to the outside and causes electromagnetic interference in the surroundings can be solved.

In this cable, the inner tube 8 and the outer tube 9 have substantially the same structure as a conventional single-line water-cooled cable in which a hollow conductor of a wire supported by a spring is covered with an insulator. Therefore, the flexibility of the cable required for moving the heating coil of the induction heating furnace is secured as in the conventional case.

The water-cooled cable of the present invention shown in FIG. 1 can be manufactured according to a conventional method of manufacturing a water-cooled cable. First, cover the spring 2 with the wire-shaped conductor 1.
The inner tube 8 is manufactured by covering the insulating tube 3 made of vinyl or the like and crimping the terminal with a copper pipe of the terminal 21. Next, the wire conductor 5 is covered on the spring 6 having a large diameter, and the copper pipe of the terminal 22 is covered with the insulating coating 7 made of rubber or the like to cover the cable. And outer cylinder 9
The water-cooled cable according to one embodiment of the present invention is manufactured by inserting the inner cylinder 8 into the terminals, inserting the terminals 21 and 22 into insulators 19 and 20 such as Teflon, and fixing the both by screws or the like. You.

In the second embodiment of the present invention, a bellows-like metal conductor is used in place of the wire conductor supported by the spring of the above-described embodiment. Bellows-shaped metal conductors are used for the inner cylinder 8 and the outer cylinder 9 instead of the spring and the wire conductor, respectively, and the other configuration is the same as that of the above-described embodiment. The bellows-shaped metal conductor is a copper-made hollow telescopic pipe-shaped one, which serves as a conductor serving as a high-frequency large current passage, has flexibility, and has a cooling water passage inside. Thus, heat generation of the conductor can be efficiently removed. Further, since the bellows-shaped metal conductor has elasticity, the bellows-shaped metal conductor plays a role of a spring in the above-described embodiment, and an inner cylinder covered with an insulating tube.
The flexibility of the cable can be secured while ensuring the mechanical strength of the outer cylinder covered with the insulating rubber sheath.

[0015]

As described above, according to the present invention, a water-cooled cable for an induction heating furnace is formed coaxially by conductors of an inner cylinder and an outer cylinder. Therefore, the high-frequency high current flowing between the power supply of the induction heating furnace and the heating coil can be uniformly flowed in the circumferential direction of the conductor while securing the flexibility of the cable and the direct water cooling of the cable conductor with the cooling water, Potential drop is greatly reduced, and power can be transmitted efficiently.

[Brief description of the drawings]

FIG. 1 is a sectional view of a water-cooled cable according to an embodiment of the present invention.

[Explanation of symbols]

 1,5 conductor 2,6 spring 3 insulating tube 7 insulating coating 8 inner cylinder 9 outer cylinder 11,12,13,14 flange 15,16 cooling water channel 19,20 insulator 21,22 terminal

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01B 7/34 H01B 11/00

Claims (2)

(57) [Claims] 1. An inner cylinder comprising a wire conductor covered by an insulating tube and supported by a spring,
An outer cylinder made of a wire conductor which is arranged coaxially with respect to the inner cylinder, is covered with an insulator, and is supported by a spring, and a cooling water is provided between the inner cylinder and the inner cylinder and the outer cylinder. A water-cooled cable characterized in that the cable is circulated. 2. An inner cylinder covered with an insulating tube and made of a bellows-shaped metal conductor, and an outer cylinder arranged coaxially with the inner cylinder and covered with an insulator and made of a bellows-shaped metal conductor. A water-cooled cable, wherein the cooling water flows through the inner cylinder and between the inner cylinder and the outer cylinder.