JPS62127180A - Leakage detecting device for conductive liquid metal of rotary roll electrode - Google Patents

Abstract

PURPOSE:To provide the titled detecting device enabling to discover ealier the leakage of a conductive liquid metal by composing so as to detect the electrifying state due to said leakage by the leakage detecting part which equips with a conductor by arranging at minute intervals at the close position of a rotary roll. CONSTITUTION:A rotary roll electrodes supporting body 21 and the left side print wiring part 22 are connected and become in electrifying state in case of a conductive liquid metal 4 being adhered to a leakage detector 20 with its leakage from the left side of a rotary roll electrode A. In this case the left side memory circuit 33 outputs a leakage detecting signal a successively to the left side leakage display lamp 41 due to the left side electrification detecting circuit 31 becoming in electrifying state and lights a lamp 41 and integral leakage display lamp 43. Even in case of the metal 4 being leaked from the right side of the electrode A the support body 21 and right side print wiring part 23 are connected and become in electrifying state similarly and the right side leakage display lamp 42 and lamp 43 are lit. Consequently the leakage detection of not only the liquid metal easy to evaporate of Hg, etc. but also the conductive liquid metal difficult to evaporate like the easily melting alloy of Ga main body can be performed as well.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a fixed part of a rotating roll electrode used for electrical resistance seam welding of overlapping metal plates such as the side seam of a can body molded body. The present invention relates to a conductive liquid metal leakage detection device for detecting leakage of conductive liquid metal sealed in a gap between a rotating part and a rotating part.

(Prior art) In recent years, the overlapping part of a can body formed by rolling metal plates such as tin-plated steel plates and nickel-plated steel plates into a cylindrical shape and overlapping both end edges is connected via copper wire electrodes. Can bodies are manufactured by an electric resistance seam welding method in which welding is performed by applying current to a rotating roll electrode on the inner surface of a molded can body and a rotating roll electrode on the outer surface of the molded can body by applying pressure therebetween.

As shown in FIG. 13, the rotating roll electrode used in this electric resistance seam welding includes a fixed part 100 and a rotating part 102 rotatably mounted around the fixed part 100 via an insulated bearing lot. We are prepared.

The fixed part 100 has a disk-shaped part 100a in the axial center part.
The outer circumferential surface of the disc-shaped portion 100a faces the inner surface of the rotating portion 102 with a small gap therebetween.

A conductive liquid metal 10 is provided in the gap formed between the outer circumferential surface of the disk-shaped portion 100a and the inner surface of the rotating portion 102.
3 is included.

The fixed part 100 and the rotating part 102 are made of copper or a copper alloy, which is a conductive metal, so that the welding current flows from the fixed part Zoo through the liquid metal 103 in the gap to the rotating part 102.

Here, regarding the conductive liquid metal 103 sealed in the cavity of the rotating roll electrode, mercury has traditionally been widely used, but since mercury is highly toxic, it has been recently Easily fusible alloys based on gallium, such as Ga, In, and Sn.

A large-scale alloy consisting of Zn, Ag, and A-mono, Ga.

A binary alloy consisting of In, Ga, In, and Sn.

The use of quaternary alloys made of Zn has been proposed (Japanese Patent Publication Nos. 55-40355, 40359/1980, 62680/1980, 77/198).
No. 076), which the applicant himself uses in part.

In order to prevent the liquid metal 103 from leaking from the joint between the fixed part 100 and the rotating part lO2, the liquid metal 103 is
A sealing material 104 such as a seal ring is installed between the fixed part 100 and the rotating part 102 adjacent to the cavity in which 03 is sealed, but this sealing material 104 wears out due to long-term use of the rotating roll electrode. Therefore, it cannot be said that this is sufficient to prevent the liquid metal 103 from leaking.

Normally, the rotating roll electrode is replaced before the sealed liquid metal starts leaking, that is, before the rotating roll electrode reaches the end of its life, so liquid metal rarely leaks from the rotating roll electrode. Since the lifespan of the rotating roll electrode varies due to variations in the sealing material and other parts, if a rotating roll electrode with a short lifespan is unintentionally used, there is a risk of leakage of liquid metal as described above.

By the way, when liquid metal leaks, the amount of leakage is almost always small, and the rotating roll electrode and leaked liquid metal are often hidden by the can body that is being welded as it passes through. It is almost impossible for an operator to detect liquid metal leaks with the naked eye during welding.

If liquid metal leaks from the rotating roll electrode, it may adhere to the welded can body. In particular, if liquid metal adheres to the can body intended for canning food and beverages, it may be toxic as liquid metal. It is unfavorable from a sanitary standpoint not only when mercury, which is highly toxic, is used, but also when an easily fusible alloy mainly composed of gallium, which is said to be almost non-toxic, is used.

In addition, liquid metal acts as a conductive medium that electrically connects fixed parts and rotating parts, and leakage of liquid metal means a decrease in liquid metal. This is not preferable as it may cause defects.

Therefore, a leakage detection device for detecting leakage of liquid metal was devised as described below.

This leakage detection device uses a correction coating that is applied to the welded part of the can body immediately after welding when the liquid metal adheres to the can body due to leakage from the rotating roll electrode when using a liquid metal that easily vaporizes, such as mercury. When drying and baking, the adhered liquid metal vaporizes and is included in the gas in the heating furnace.The gas in the heating furnace is sampled at predetermined intervals or continuously to detect mercury from the gas. This was used to detect liquid metal leakage from the rotating roll electrode.

(Problems to be Solved by the Invention) However, such conventional conductive liquid metal leakage detection devices using rotating roll electrodes detect leakage of liquid metal by detecting vaporized liquid metal. There is a problem in that it is difficult to detect leakage of liquid metals that are difficult to vaporize, such as easily melted metals mainly composed of.

In addition, leakage of liquid metal is not detected until the dry-baking process after welding occurs, and countermeasures are delayed, so when a leak is detected, a large number of can bodies that have been welded together after a leak have to be discarded.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and to achieve this purpose, the present invention includes a fixed part and the surroundings of the fixed part. Leakage detection system equipped with a conductor placed close to a rotating roll electrode with a conductive liquid metal sealed in the gap between the rotary part and the rotary part rotatably attached to the rotary part. and a leakage detection circuit that is connected to the leakage detection section and outputs a leakage detection signal by detecting an energized state in which the conductor is connected and energized due to leakage of conductive liquid metal. This is a conductive liquid metal leak detection device for electrodes.

(Function) Therefore, in the electroconductive liquid metal leakage detection device for a rotating roll electrode of the present invention, if the electroconductive liquid metal leaks from the rotating roll electrode and adheres to the leakage detection part disposed in the vicinity of the rotating roll electrode. The conductor of the leakage detection part is connected and becomes energized, and by detecting this energization state and outputting a leakage detection signal by the leakage detection circuit, leakage of liquid metal can be detected in the welding process.

(Example) Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

First, a conductive liquid metal leak detection device for a rotating roll electrode according to a first embodiment shown in FIGS. 1 to 6 will be described.

First, the one-rotation roll electrode A will be explained.

This rotating roll electrode A is axially supported by being inserted into a rotating roll electrode support, and as shown in FIGS. 2 and 3, it has a fixed part 1, a rotating part 2, an injection hole 3, a conductive liquid It includes a metal 4, an electroplated layer (metal coating) 5, a support bearing 6, a seal ring 7, and an insulating ring 8.

The fixed part 1 is formed with a disk-shaped part 1a at the center in the axial direction, and a shaft part 1b which is pivoted to the rotating roll electrode support 21 at both ends.A cooling water channel is provided inside the disk-shaped part 1a to prevent overheating. 9 is provided.

The rotating part 2 is rotatably mounted around the fixed part 1 via a support bearing 6.6, and includes a conductive rotor part 2a made of a highly conductive metal and an easily fusible metal mainly made of gallium. The anti-corrosion rotor part 2b is made of a metal that is not easily corroded by corrosion.

The conductive rotor portion 2a is formed with an electrode wire insertion groove 1O into which the electrode wire is wound during use, and a conductive liquid metal 4 is formed at the combined joint portion of the conductive rotor portion 2a and anti-corrosion rotor portion 2b. 0-ring 1 to prevent leakage.
1 is provided.

The injection hole 3 is a hole for injecting the conductive liquid metal 4 into the gap 12 formed between the fixed part 1 and the rotating part 2 using a syringe or the like. 2b, and a hole is made on the side where less welding current flows.

Note that after injecting the conductive liquid metal 4 into the injection hole 3,
A plug 13 and a backing 13 are used to seal the cavity.
' is provided.

The conductive liquid metal 4 is an easily fusible metal mainly composed of gallium, which is sealed in the gap 12 between the fixed part 1 and the rotating part 2 so that welding current can flow from the fixed part 1 to the rotating part 2 during welding. .

The electroplating layer 5 is applied to a portion of the fixed portion l facing the cavity (mainly the outer circumferential surface of the disc-shaped portion 1a) and a conductive rotor portion of the rotating portion 2. It is formed by electroplating on the inner surface facing the cavity 12 of a.

The support bearing 6 is a support member for rotatably supporting the rotating part 2 with respect to the fixed part 1. An insulating ring 8.8 made of an insulating material is interposed between the support bearing 6 and the rotating part 2. Furthermore, a seal ring 7.7 is interposed between the support bearing 6 and the gap 12 to prevent leakage of the conductive liquid metal 4.

Note that 14 in the figure is a bearing retaining ring.

Next, the materials of each part employed in the rotating roll electrode A of the first embodiment will be described.

For the fixed portion l, a highly conductive Cu-Cr alloy (copper-chromium alloy) was used.

The conductive rotor portion 2a of the rotating portion 2 is made of highly conductive C.
A u-Be alloy (copper/beryllium alloy) was used, and 5US304 (iron-based alloy) was used for the anti-corrosion rotor portion 2b.

In electroplating calendar 5, Co--W electroplating with a Co:W (cobalt:tungsten) weight ratio of 4=6 was applied to a plating thickness of 5 to log.

The conductive liquid metal 4 includes 65.5% Ga (gallium) and 21.3% In (indium).

An easily fusible alloy consisting of a quaternary alloy mainly composed of gallium mixed in a weight ratio of 9.6% Sn (tin) and 3.6% Zn (zinc) was used.

Next, the conductive liquid metal 4 sealed in the rotating roll electrode A
Leakage detection device B that detects leakage will be explained.

This leak detection device B includes a leak detection section 20 and a leak detection circuit 3.
0 (see Figure 1).

The leakage detection unit 20 includes a rotating roll electrode support (first conductor) 21, and a left printed wiring board 22 and a right printed wiring board 23 provided on both left and right sides of the rotating portion 2 of the rotating roll electrode A. It is configured.

The rotating roll electrode support 21 is made of conductive metal and is connected to a power source 50.

The left (right) printed wiring board 22 (23) is the fourth
As shown in FIG. 6, the comb is disposed in the lower half of the periphery of the shaft portion 1b in the gap between the rotating roll electrode support 21 and the rotating portion 2, and is fixed to the rotating roll electrode support 21. An insulator 24 (25) formed in a shape is used as a substrate, and a printed wiring portion (second conductor) 26 (27) is printed.

In this embodiment, the shortest distance between the printed wiring section 26 (27) and the portion of the rotating roll electrode support 21 that is not covered with the insulator 24 (25) is .

The position of the printed wiring part 26 (27) and the thickness of the insulator 24 (25) were selected so that the thickness was approximately 2 mm. It may be selected from the range of 0.5 to 10 mm.

Note that the left printed wiring board 22 and the right printed wiring board 23 have exactly the same configuration, so only the left printed wiring board 22 is shown in the drawing, and the right printed wiring board 2 is shown in the drawing.
3, the reference numerals will be omitted by writing them in parentheses next to the reference numerals indicating the same parts of the left printed wiring board 22.

The leakage detection circuit 30 is connected to the leakage detection section 20, and includes a left side energization detection circuit 31, a right side energization detection circuit 32, a left side storage circuit 33, and a right side storage circuit 34.
It is equipped with

The left side energization detection circuit 31 and the right side energization detection circuit 32 are
They are connected in series to the left printed wiring section 26 and the right printed wiring section 27, respectively, and are also connected to a power source 50, so that leakage of the conductive liquid metal 4 may cause damage to the rotating roll electrode support 21 and the left or right printed wiring. Part 2
6.27 is connected and energized, it becomes energized.

Further, the left side memory circuit 33 and the right side memory circuit 34 are connected in series to the left side energization detection circuit 31 and the right side energization detection circuit 32, respectively, and are also connected to the reset button 51. Once the .32 becomes energized, it continuously outputs the leakage detection signal a to the leakage display circuit 40.

Note that the output of the leakage detection signal a is canceled by replacing the rotating roll electrode from which the liquid metal has leaked, removing the liquid metal leaked into the leakage detection section 20, and then resetting it with the reset button 51.

The leak indicator circuit 40 is connected in series with a left leak indicator lamp 41 connected to the left memory circuit 33, a right leak indicator lamp 42 connected to the right memory circuit 34, and both leak indicator lamps 41 and 42. General leak indicator lamp 4
3, and when the leakage detection signal a is input, these lamps 41, 42, 43 are turned on and the conductive liquid metal 4 is turned on.
This indicates the leakage of the data.

Next, the operation of the first embodiment will be explained.

When the conductive liquid metal 4 leaks from the left side of the rotating roll electrode A and the leaked conductive liquid metal 4 adheres to the leak detection part 20, the rotating roll electrode support 21 and the left printed wiring part 22 are connected. It becomes energized.

At this time, the left energization detection circuit 31 becomes energized, so
The left side memory circuit 33 continuously outputs the leak detection signal a to the left side leak indicator lamp 41, causing the left side leak indicator lamp 41 and the comprehensive leak indicator lamp 43 to light up.

Note that even if the conductive liquid metal 4 leaks from the right side of the rotating roll electrode A and adheres to the leakage detection part 20, the one-turn roll support 21 and the right printed wiring part 23 are similarly connected and become energized. The right side leak indicator lamp 42 and the general leak indicator lamp 43 are lit.

Next, a second embodiment shown in FIGS. 7 to 9 will be described.

In this embodiment, the leak detection section 20 is constituted by a left printed wiring board 60 and a right printed wiring board 70 provided on both left and right sides of the rotating portion 2, and this left (right) printed wiring board 60 (70) The first printed wiring section (first conductor) 62 is printed in a comb shape using the insulator 61 (71) fixed to the rotating roll electrode holder 21 as a substrate.
63 (72, 73) and a second printed wiring portion (second conductor) 64.65 (74, 75).

In addition, these first printed wiring parts 62, 63 (72, 7
3) and the second printed wiring parts 64, 65 (74, 75) are arranged alternately, and the adjacent printed wiring parts are 0.
．． The comb teeth are interlocked with each other with a micro spacing of 5 to 10 mm.

Further, the first printed wiring sections 62, 63 (72, 73) are connected to the power source 50, and the second printed wiring sections 64
．． 65 (74, 75) is the left (right) leak detection circuit 3
1 (32).

Note that the other configurations are the same as those in the first embodiment, so the same reference numerals are used in the drawings and explanations thereof will be omitted.

Furthermore, since the operation is similar to that of the first embodiment, the explanation will be omitted.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, in the embodiment, a printed wiring section is used as a conductor in the leak detection section, but other metals or the like may be used as a conductor as long as it has conductivity.

Further, in the embodiment, when a leak is detected, a lamp is turned on to indicate the leak, but a buzzer may be used to indicate the leak, or the operation of the welding device itself may be stopped.

In addition, when a rotating roll electrode support and a printed wiring part are used as conductors in the leakage detection part, the printed wiring board is not limited to the comb-shaped one shown in the first embodiment.
As shown in diagram O, there are those that force multiple arcs with different diameters,
They may have a radial shape as shown in FIG. 11 or a mesh shape as shown in FIG. 12.

(Effects of the Invention) As described above, in the electroconductive liquid metal leakage detection device for a rotating roll electrode of the present invention, the leakage detection section including the conductors spaced apart by a minute gap is connected to the rotating roll electrode. Since a leakage detection circuit is placed close to the leakage detection section and outputs a leakage detection signal by detecting an energized state in which the conductor is connected and energized due to leakage of conductive liquid metal, the leakage detection circuit is connected to the leakage detection section. It is possible to detect leakage not only of liquid metals that are easily vaporized, such as liquid metals, but also of conductive liquid metals that are difficult to vaporize, such as easily fusible alloys mainly composed of gallium.

Moreover, since conductive liquid metal leakage detection is performed close to the rotating roll electrode, conductive liquid metal leakage can be detected early, thereby preventing adhesion of conductive liquid metal to the can body and welding defects. The number of can bodies that must be discarded due to conductive liquid metal adhesion, poor welding, etc. can be reduced.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a conductive liquid metal leak detection device for a rotating roll electrode according to a first embodiment of the present invention, FIG. 2 is a sectional view showing a rotating roll electrode on which the device of the first embodiment is installed, and FIG. The figure is a cross-sectional view showing the main part of the rotating roll electrode, FIG. 4 is a cross-sectional view taken along the line I-I in FIG. 1, FIG. 5 is a cross-sectional view taken along the line ■-■, FIG. 7 is a cross-sectional view showing the leakage detection section of the device of the second embodiment,
Fig. 8 is a plan view showing the main part M in Fig. 7, Fig. 9 is a sectional view taken along the line ■-■ in Fig. 8, and Figs.
Cross-sectional view showing a modification of the leak detection section of the embodiment device, No. 13
The figure is a sectional view showing a rotating roll electrode. A...Rotating roll electrode 1...Fixed part 2...Rotating part 4...Conductive liquid metal 12...Gap part 20...Leakage detection part 21...Rotating roll electrode support 24 .25...Insulator 26.27...Printed wiring part (conductor) 30...
Leakage detection circuit a...Leakage detection signal

Claims (1)

[Scope of Claims] 1) Disposed near a rotating roll electrode in which conductive liquid metal is sealed in a gap between a fixed part and a rotating part rotatably mounted around the fixed part, and a leakage detection section including conductors spaced apart at minute intervals; the leakage detection section is connected to the leakage detection section, and detects an energized state in which the conductor is connected and energized due to leakage of the conductive liquid metal, and detects the leakage. A conductive liquid metal leak detection device for a rotating roll electrode, comprising: a leak detection circuit that outputs a detection signal; 2) The electrically conductive liquid of the rotating roll electrode according to claim 1, wherein the leakage detection unit uses the rotating roll holder as the first conductor and the printed wiring section having the insulator as the substrate as the second conductor. Metal leak detection device. 3) The electrical conductivity of the rotating roll electrode according to claim 1, in which the leakage detection section uses printed wiring sections, which are arranged in combination and adjacent to each other using an insulator as a substrate, as the first conductor and the second conductor. Liquid metal leak detection equipment.