JPS62173078A - Rotating electrode type cutting device - Google Patents

Abstract

PURPOSE:To lower an electric resistance of a shaft, and to prevent effectively the generation of Joule head and the heat reserve, by embedding a high conductive material into a shaft center part of a shaft of a rotating electrode type cutting device. CONSTITUTION:A core material 103 made of copper is embedded in a shaft 101. The core material 103 consists of a high conductive material and the generation of Joule heat of the shaft 101 is suppressed, and a temperature rise is relaxed. By a rotation of the shaft 101, a rotating electrode 1 rotates, and approaches an object 9 to be cut by a movement of a casing 2. When it has approached a prescribed distance, the object 9 to be cut is cut by executing an arc discharge. In this case, Joule heat is generated to the rotating electrode 1 side from a collector ring 39 of the shaft 101, but it is diffused by a heat transfer of the periphery of the shaft 101. According to this constitution, an electric resistance of the shaft is lowered, the generation of Joule heat is prevented, and the reliability as a cutting device can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a rotating electrode type cutting device used when cutting steel materials, etc., for example, in buildings or facilities where the environment is deteriorated.

Technical Background of the Invention In general, various types of equipment in various plants reach the end of their service life after long-term use. In that case, it is necessary to completely dismantle and remove the equipment by cutting it off or otherwise.

The cutting methods include the following. That is, gas cutting methods, methods combining gas cutting methods and gouging methods, electrode water jet cutting methods, plasma cutting methods, electric discharge machining methods, and the like.

However, this method has the following problems. For example, in the case of the gas cutting method described above, if there is a cladding of austenitic stainless steel, cutting becomes impossible. Furthermore, the method that combines the gas cutting method and the gouging method has the problem of producing many by-products.

Therefore, the following rotating electrode cutting method has been considered. This will be explained below with reference to FIGS. 2 to 4. Reference number 1 in FIG. 2 indicates a rotating electrode, and this rotating electrode 1 is fixed to a shaft 3 rotatably installed in a casing 2. As shown in FIG. 3, slits 1A are formed at equal intervals in the circumferential direction on the outer peripheral edge of the rotating electrode 1, and the slits 1A scrape out and eliminate the molten material (molten slag) generated during cutting. . The shaft 3 is connected to a hydraulic motor 4 installed outside the casing 2,
By driving this hydraulic motor 4, the rotating electrode 1 is rotated.

A copper brush 5 is installed inside the casing 2 and around the outer periphery of the shaft 3, and this copper brush 5 is connected to one pole (-pole) of a DC power source 7 via a cable 6. Further, the object to be cut 9 is connected to the other pole (child) of the DC power supply 7 via a cable 8 .

The casing 2 is a piston 1 of a hydraulic cylinder mechanism 10.
1, and therefore, as the piston 11 slides (in the direction indicated by the arrow in the figure), the casing 2 slides in the direction toward and away from the object 9 to be cut. The hydraulic cylinder mechanism 10 is controlled by a servo system 12. That is, when cutting is performed by bringing the rotating electrode 1 close to the object 9 to be cut, the cutting current is detected by the ammeter 13 inserted in the cable 6, and the detection signal is sent to the current comparator 1.
4 is input. In addition to the detection signal described above, a control signal preset by a control panel 15 is input to the current comparator 14. The current comparator 14 compares these detection signals and control signals and outputs the difference therebetween to the servo system 12 as a difference signal.

The servo system 12 operates the hydraulic cylinder mechanism 10 based on this difference signal.
The purpose is to control the cutting current to maintain a constant cutting current. Note that reference numeral 16 in the figure indicates an air inlet, and compressed air as a shielding gas is injected into the casing 2 through this air inlet 16 to shield the power supply portion to the rotating electrode 1.

According to the above configuration, when cutting the object 9, first the hydraulic motor 4 is driven to rotate the rotary electrode 1, and the hydraulic cylinder mechanism 10 is driven to rotate the piston 1.
1 downward in the figure, and the rotating electrode 1 is placed on the object 9 to be cut.
approach. The rotating electrode 1 is approximately zero relative to the object to be cut 9.
．． Arc discharge is performed at a point 1 to 0.2 degrees away, and DC low voltage and high current (50V in terms of voltage).

The object 9 to be cut is melted and cut by electrical energy with a current of about 4000 A to 2000 OA), and melting slag is removed through the slit 1A.

Next, the configuration of the head portion of the rotating electrode type cutting device will be explained in detail with reference to FIG. FIG. 4 is a sectional view of the head section, and the rotating electrode 1 has a pair of flanges 31A, 3
1B, and in this state is fixed to the shaft 3 via a collar 32 with a screw 33. Reference numeral 34 in the figure indicates a bolt fixing the flanges 31A and 31B. The shaft 3 has both ends covered with an insulator 35.
A and 35B are respectively supported by rolling bearings 36A and 36B. These rolling bearings 36A, 36B
are bearing chambers 37A, 37 formed in the casing 2.
The brush chamber 38 is installed in the brush chamber 38, and the portion where the brush 5 is installed serves as a brush chamber 38. Note that a collector ring 39 is installed between the brush 5 and the shaft 3. The brush 5 is composed of a plurality of divided brushes 5A, and each divided brush 5A is biased toward the collector ring 39 by a spring 40, respectively. Further, the biasing force of these brushes 5A is adjusted as appropriate by adjusting screws 41.

A spline 4 is connected between the shaft 3 and the hydraulic motor 4.
2 is intervening. A tacho line 43 is attached to the outer periphery of this spline 42. Also, the number 44.4 in the figure
Reference numeral 5 indicates the inlet and outlet flanges of the hydraulic motor 4, reference numeral 46 indicates a bolt fixing the hydraulic motor 4 to the casing 2, reference numeral 47 indicates a stopper, and reference numeral 48 indicates a cover.

[Problems with the Background Art] With the above configuration, for example, during cutting work, phenomena such as an abnormal decrease in rotational speed, seizure due to an abnormal temperature rise in the bearing 23, or cracks in a portion of the casing 2 occur. There are things to do. These problems are caused by Joule heat being generated in the shaft 3 by supplying a large current to the rotating electrode 1, and the decrease in rotational speed as described above not only reduces the ability to discharge molten slag during cutting, but also causes a rise in temperature. There is a risk that the bearing 36A, which has the lowest allowable limit, may seize and the casing 2 may be damaged, making it impossible to continue operation. In the unlikely event that such a situation occurs while cutting work is being carried out in a place with a degraded environment, the worker must disassemble and replace each part in the place with a degraded environment. There was a problem in terms of ensuring the safety of the work.

[Purpose of the Invention] The present invention has been made based on the above points, and its purpose is to solve situations where cutting ability is reduced or continuous operation becomes impossible due to various adverse effects caused by Joule heat generation in the shaft. It is an object of the present invention to provide a cutting device that can cut even thick steel materials at high speed and improve reliability.

[Summary of the Invention] That is, the rotating electrode type cutting device according to the present invention includes a casing, a shaft rotatably housed in the casing and having both ends pivotally supported by bearings installed in a bearing chamber, and a shaft at the tip of the shaft. In a rotating electrode type cutting device that includes a fixed rotating electrode and a control mechanism that reciprocates the shaft in the direction of the object to be cut, the electrical resistance of the shaft is reduced by using a highly conductive material at the axial center of the shaft. This aims to suppress the generation of Joule heat due to the current flowing through the shaft, thereby suppressing the temperature rise of the shaft.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIG. Note that parts that are the same as those in the prior art are denoted by the same reference numerals, and their explanations will be omitted. FIG. 1 is a sectional view showing the head portion of the rotating electrode type cutting device according to this embodiment. Reference numeral 101 in the figure is a shaft, and an elongated hole 102 is formed in the axial center of the shaft 101 in the axial direction from the rotating electrode 1 side. A copper rod 103 is fitted into the elongated hole 102 by shrink fitting. The bar material 103 has high conductivity, and as a result, the electrical resistance of the shaft 101 becomes small.

According to the above configuration, the rotating electrode 1 rotates due to the rotation of the shaft 101, and approaches the workpiece 9 as the casing 2 moves. When the object 9 approaches to a predetermined distance, arc discharge is performed to cut the object 9 and remove melting slag through the slit 1A of the rotating electrode 1.

In such a cutting operation, a cutting current flows between the rotating electrode 1 and the collector ring 39 via the shaft 101. At this time, Joule heat is generated in a portion of the shaft 101 closer to the rotating electrode 1 than the collector ring 39. The Joule heat is dissipated around the shaft 101 by heat transfer. And if a lot of Joule heat is generated, shaft 10
The generated heat is stored in the shaft 10113 and the bearing 36A, causing a rise in temperature. However, the shaft 101 according to this embodiment
Since the core material 103 made of copper is embedded in the shaft 101, the electrical resistance of the shaft 101 is reduced, the generation of Joule heat is suppressed, and as a result, the rise in humidity of the shaft 101 is alleviated.

At the same time, it is also possible to suppress the temperature rise of the rolling bearing 36A.

As described above, according to this embodiment, the temperature rise of the shaft 101 and the rolling bearing 36A can be effectively suppressed, and the seizure of the rolling bearing 36A and the decrease in rotational speed, etc. are eliminated, and the reliability of the device is greatly improved. be able to. Therefore, even thick steel materials can be cut at high speed.

Next, a second embodiment will be described. That is, the first
In the case of the above embodiment, the core material 103 is inserted from the end of the shaft 101 on the rotating electrode 1 side, but the same effect can be achieved by inserting it from the hydraulic motor 4 side. Further, in the case of the first embodiment, since the hole 102 is formed continuously with the screw hole for the screw 33, the hole 102 is formed continuously with the screw hole for the screw 33.
It is necessary to make the diameter of screw 2 smaller than the diameter of screw 33. Therefore, there is a limit to the expansion of the diameter of the core material 103, that is, a decrease in the electrical resistance of the shaft 101, but in the case of the second embodiment, there is no υ1 limit, and the shaft 101 It is possible to lower the electrical resistance of the heat exchanger, and to more effectively prevent the harmful effects of Joule heat generation and heat accumulation.

Further, in the first F3 and the second embodiment, if a hole is formed in the radial direction in the cylindrical portion of the shaft 101 at the collector ring 39 position, and a copper bar or the like is fitted into the hole by shrink fitting, It becomes possible to further effectively reduce the electrical resistance of the shaft 101.

Note that highly conductive materials are not limited to copper;
Any material may be used as long as it has a higher conductivity than the shaft 101.

[Effects of the Invention] As detailed above, according to the rotating N-pole type cutting device according to the present invention, the electrical resistance of the shaft is reduced, thereby effectively preventing the generation and accumulation of Joule heat, and reducing the Joule heat. It is possible to prevent various adverse effects caused by heat generation and heat accumulation, and to greatly improve the reliability of the cutting device.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the head of a rotating N-pole type cutting device showing an embodiment of the present invention, FIGS. 2 to 4 are views showing conventional examples, and FIG. A diagram showing a schematic configuration,
FIG. 3 is a plan view of the rotating electrode, and FIG. 4 is a sectional view of the head portion of the rotating electrode type cutting device. DESCRIPTION OF SYMBOLS 1... Rotation Nri, 2... Casing, 9... Object to be cut, 10... Hydraulic cylinder mechanism, 101... Shaft, 102... Hole, 103... Core material.

Claims (2)

[Claims] (1) A casing, a shaft that is rotatably housed in the casing and whose both ends are supported by bearings installed in a bearing chamber, a rotating electrode fixed to the tip of the shaft, and a shaft to be cut. What is claimed is: 1. A rotating electrode cutting device comprising a control mechanism for reciprocating in the direction, characterized in that a highly conductive material is embedded in the axial center of the shaft. (2) The rotating electrode according to claim 1, wherein the highly conductive material is a copper bar, and the copper bar is embedded in the shaft by shrink fitting. type cutting device.