JPH0262515B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for joining ceramics by melting and joining while swinging an arc generated between electrodes facing a ceramic joint by a magnetic field.

[Prior Art] FIG. 5 is a schematic diagram showing an electrical bonding device for ceramics prior to the present invention. For example, when non-conductive ceramics are to be bonded, there is a After interposing the adhesive 3 which is conductive at high temperature, the joint is heated with a gas flame generated from the tips of the blowpipe 4 and 5 installed on both sides of the joint, and 1 to 1 is placed between the electrodes 6 and 7. 10Kv
Apply current or alternating voltage. Power supply device 14
As long as it has a no-load voltage of about 1 to 10 kV, it is sufficient. Although the output current is not constant depending on the area of the junction, etc., it is usually a small current of about several amperes or less. The ceramics at the joints heated to a high temperature by the gas flame become highly conductive, and the blowpipe 4, 5
The charge carried by the gas flame from the electrode passes through the ceramics of the joint, energizing the electrodes.

At this time, the bonded portion is heated in a short time by resistance heat generated in the ceramics, that is, joule heat, and the ceramics are firmly bonded. When the joint is rapidly heated by Joule heat, the electrical resistance value decreases significantly and the conductivity rapidly increases.
For this reason, an output current control device 15 is required to maintain the current at an appropriate value. An appropriate current value is appropriately determined depending on the type of ceramics used.

[Problems to be Solved by the Invention] In the conventional method, unless the joining length is very small, it is necessary to move the current-carrying part by moving the blowpipe and the electrode or by moving the ceramics to perform the joining one after another. I was doing it. Furthermore, in the conventional energization method, since the molten pool is narrow, the temperature in the periphery of the molten pool rapidly decreases, resulting in a state in which the electrical resistance value in this area rapidly increases. For this reason, the counter electrode part is now the molten pool part (hereinafter referred to as P ₁ ).
Even if you move away from P 1, the current-carrying part does not follow the counter electrode smoothly and stays at P ₁ due to the large electrical resistance of this part, and when you move further away from P ₁ , the current-carrying part suddenly changes to the current counter electrode. (hereinafter referred to as P ₂ ), and a new molten pool is generated in the P ₂ part (discontinuous transition of the molten pool). At this time P ₁ and P ₂
Incomplete bonding tends to occur between the two.

The present invention aims to eliminate discontinuous transition of the molten pool by increasing the size of the molten pool, thereby preventing the occurrence of incompletely joined portions.

[Means for Solving the Problems] The method of the present invention applies a Lorentz force to an earth current by a magnetic field generated by an electromagnet placed near a joint of ceramics, and this force causes a current-carrying part to swing. The purpose is to expand the molten pool area.

[Operation] When joining ceramics, a magnetic field is applied to the vicinity of the joint using an electromagnet or the like in a direction perpendicular to both the direction in which the energizing position is desired to be moved and the direction between the opposing electrodes.

Consider the case where current is being applied between the electrodes, an arc is generated in the gap between the electrode and the ceramic surface, and the ceramic joint has high conductivity and is in a current-carrying state. At this time, when the magnetic field described above is applied, a Lorentz force acts on the interelectrode current-carrying part according to Fleming's left hand measurement.

If either the inter-electrode power source or the electromagnetic excitation coil power source is AC, and the other is DC, the Lorentz force causes the arc to oscillate in the direction in which the energized position is desired to be moved, in synchronization with the frequency of the AC. This arc oscillation causes the molten pool at the ceramic joint to expand, so that complete joining can be achieved without discontinuities in the joint.

[Example] Example 1 The following description will be given with reference to FIGS. 1 and 2.
In Example 1, prismatic ceramics 1 and 2 were bonded with adhesive 3.
This shows the case of butting and current-carrying.

A pair of blowpipe 4, 5 and electrodes 6, 7 are arranged opposite the ceramic joint.

Electrodes 6 and 7 are mounted in the blowpipe 4 and 5, respectively, with the tips of the electrodes protruding from the openings of the blowpipe. The gap between the tip of the electrode and the outer surface of the ceramic joint is set to 2 to 3 mm.

A pair of electromagnetic iron cores 8 and 9 are arranged across the ceramic joint, and the tip of the electrode is located in the space between the magnetic poles, so that a strong magnetic field extends from the tip of the electrode to the outer surface of the ceramic joint. A magnetic field is generated.

Excitation coils 10 and 11 that magnetize the electromagnetic core are connected so as to generate magnetic fields in the same direction on the left and right sides of the ceramic joint.

In Example 1, an AC power source is used for the electrodes, and a DC power source is used for the excitation coil.

When the ceramic adhesive is heated by the gas flame from the blowpipe and becomes conductive, a discharge begins between the electrodes.

The no-load voltage between the electrodes is 1 to 10 kV, but the current control device 1 is used to prevent runaway due to the process of temperature rise due to discharge current → resistance value decrease → discharge current increase.
Install 5.

Now, when the direction of the magnetic field B ₂ due to the current I ₁ between the electrodes and _the current I 2 of the excitation coil is in the direction of the solid arrow shown in Figure 1, the Lorentz force F is determined by Fleming's left hand method as shown in the paper in Figure 1. The arc moves in the back direction, that is, in the direction of the solid arrow shown in FIG. 2, and the current-carrying portion within the ceramic also moves accordingly. When the direction of the current between the electrodes is reversed in the direction of the dotted arrow, the direction of the Lorentz force is also reversed, and the moving direction of the arc and the moving direction of the current-carrying part are also reversed. By repeating this, the current-carrying portion within the ceramic oscillates over the entire length of the joint in synchronization with the alternating current frequency. As a result, the entire length of the ceramic joint is uniformly heated, melted, and joined. In the above description, the inter-electrode energizing power source is AC and the excitation coil power source is DC; however, conversely, the inter-electrode energizing current may be DC and the excitation coil power source is AC.

Example 2 If the joining length of ceramics is long, it is not possible to join the entire length just by swinging the arc, so by moving the blowpipe and electrode while swinging the arc, or by moving the ceramics. , the bonding is performed by changing the relative positions of the blowpipe and electrode and the bonding portion of the ceramic.

FIGS. 3 and 4 show an embodiment of the present invention, in which flat plates 1 and 2 having long joints are butt-joined with an adhesive 3 interposed therebetween. This will be explained below with reference to FIGS. 3 and 4.

A pair of blowpipes and electrodes are positioned against the ceramic joint. The gas flame ejected from the blowpipe 4, 5 is directed towards the ceramic joint. Electrodes 6 and 7 are mounted in the blowpipe 4 and 5, respectively, with the tips of the electrodes protruding from the openings of the blowpipe. The gap between the tip of the electrode and the outer surface of the ceramic joint is set at 2 to 3 mm.

A pair of electromagnets 8 and 9 are placed across the ceramic joint, and the tip of the electrode is located in the gap between the magnetic poles, creating a strong magnetic field from the tip of the electrode to the outer surface of the ceramic joint. occurs. Excitation coils 10 and 11 that magnetize the electromagnetic core are connected so as to generate magnetic fields in the same direction on the left and right sides of the ceramic joint.
In the second embodiment, a DC electrode is used as the electrode, and an AC power source is used as the excitation coil.

The ceramics are placed on a table 16 and fixed to the table with fixing fittings (not shown). There is a rack 17 on the table,
A pinion 18 is engaged with this rack. The pinion is rotated by a drive device (not shown), and the rotation of the pinion causes the ceramic to move in the left-right direction in FIG. 4.

Before starting the bonding work, the ceramics are arranged so that the electrode faces the left end in the left-right direction of the ceramic bonded portion.

When the ceramic adhesive is heated by the gas flame from the blowpipe and becomes conductive, a discharge begins between the electrodes. Although the no-load voltage between the electrodes is 1 to 10 kV, a current control device 15 is installed to prevent runaway due to the process of temperature rise due to discharge current → resistance value decrease → discharge current increase.

Now, when the direction of the magnetic field B ₄ due to the current I ₃ between the electrodes and _the current I 4 of the excitation coil is in the direction of the solid arrow shown in Figure 3, the Lorentz force F is calculated by Fleming's left hand method. The arc moves in the back direction, that is, in the direction of the solid arrow shown in FIG. 4, and the current-carrying portion within the ceramic also moves accordingly. When the direction of the current between the electrodes is reversed in the direction of the dotted arrow, the direction of the Lorentz force is also reversed, and the moving direction of the arc and the moving direction of the current-carrying part are also reversed. By repeating this, the current-carrying portion within the ceramic oscillates over substantially the entire width of the electrode in synchronization with the AC frequency. On the other hand, the pinion 18 is rotated by a drive device (not shown), and the table 16 is moved to the left in FIG. 4 by the rack 17 that engages with the pinion 18. While swinging the arc in the direction of the bonding line, the ceramics and the electrode are moved relative to each other to bond the entire length of the ceramic bonding line. Since a wide molten pool is created by the arc oscillation, melting due to the relative movement between the ceramic and the electrode and movement of the parts to be joined occur evenly and continuously, resulting in a uniform and high quality product without any unwelded parts. Can be joined.

In the above description, the inter-electrode energizing power source is DC, and the electromagnet excitation electrodes are DC current, but conversely, the inter-electrode energizing power source may be DC current, and the electromagnet excitation power source may be AC. Further, the frequency of the energizing power supply or the electromagnet excitation power supply is not limited to the commercial frequency, and any frequency can be selected.

[Effects of the Invention] According to the present invention, since the molten pool becomes large, continuous and uniform bonding can be achieved.

[Brief explanation of drawings]

Fig. 1 is a layout diagram when prismatic ceramics are joined by arc swinging according to the present invention, Fig. 2 is a partially omitted/notched side view seen from the right side of Fig. 1,
FIG. 3 is a layout diagram of flat ceramics according to the present invention when the ceramics are moved and joined while arc-swinging, and FIG. 4 is a partially omitted/notched side view seen from the right side of FIG. 3. FIG. 5 is a layout diagram showing a conventional method for joining ceramics. 1, 2...Ceramics, 3...Adhesive, 4,
5...Blowpipe, 6,7...Electrode, 8,9...Electromagnetic core, 10,11...Exciting coil, 12...Power source for exciting coil, 13...Current control device for exciting coil, 14...Electrode power supply for current flow between electrodes, 15... interelectrode current flow control device, 16... table, 17...
Rack, 18...Pinion.

Claims (1)

[Claims] 1. Ceramics that are conductive at high temperatures are butted together, or ceramics are butted together with an adhesive that is conductive at high temperatures, and at least one pair of blowpipe and electrodes are provided on both sides of the joint. In the method of fusion joining by heating the joining part with a gas flame emitted from the blowpipe and generating an arc by applying a voltage between the electrodes, a heating current is applied between the electrodes. An arc oscillation welding method for ceramics in which ceramics are joined by periodically changing the phase difference between the magnetic field generated near the arc current and the arc to oscillate the arc in the direction of the joining line. 2. Butt ceramics that are electrically conductive at high temperatures or butt ceramics with an adhesive that is electrically conductive at high temperatures, arrange at least one pair of blowpipes and electrodes on both sides of the joint, and A magnetic field generated in the vicinity of the arc in a method of heating the joining part by the emitted gas flame and applying a heating current by applying the voltage between the electrodes to generate an arc and melt joining. While periodically changing the phase difference between the arc current and the arc current to swing the arc in the direction of the bonding line, the blowpipe, the electrode, and the ceramics are moved relative to each other in the direction of the bonding line to perform bonding. Arc oscillation joining method for ceramics.