JPH0587358B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a stud welding method that allows stud welding to be easily and reliably performed even on land in the rain or in puddles, and the welding method. This relates to a welding gun used for.

(Prior Art) Various welding techniques have been developed in the past, but they have the drawback that welding is difficult to perform in the rain or when there are puddles of water.

(Technical Problem) The present invention was developed in view of the shortcomings of the prior art, and its purpose is to eliminate water near the welding area and to facilitate welding even in the rain or in areas where water puddles. The technical challenge is to make it possible.

(Technical Means) The present invention has been made to solve the above technical problem, and is capable of fixing another structure or other equipment to a structure in the rain or in a puddle on land. Or regarding a method of welding a stud made of bolts, etc. for attaching a corrosion-resistant material, and a welding gun for the same, the tip of the stud held in the stud welding gun is surrounded by a heat-resistant elastic water sealing member, and a special gas generating agent is applied to the welding part. The welding current generates an arc between the stud and the base metal by attaching the water seal member to the base metal, and first, the arc heat generates gas from the gas generating agent to remove the water around the tip of the stud. Gas pressure is used to discharge the water out of the water sealing member, and then the stud is welded to the base material in a state in which water is excluded.

Specifically, as shown in the illustrated embodiment, the configuration is as follows. First, details of the welding gun shown in FIG. 1 will be explained below.

Reference numeral 1 denotes a gun body, and the gun body 1 is formed with a cylinder chamber 2 that extends from the rear end surface P to near the tip Q. A piston 3 and a coiled stud return spring 4 are built into the cylinder chamber 2. There is.

A cap 5 is screwed onto the opening 2A of the cylinder chamber 2 in a fluid-tight manner. Reference numeral 6 denotes an adjustment screw rod that penetrates the cap 5 in a liquid-tight manner, and the adjustment screw rod 6 includes:
A spring receiver 7 is screwed on. The stud return spring 4 described above is mounted between the spring receiver 7 and the piston 3 in a compressed state. A piston rod 8 is fixed to the piston 3 and projects forward through the tip of the gun body 1 in a liquid-tight manner.A chuck 9 is attached to the tip of the piston rod 8.

Further, a cover 10 and a cylinder 11 made of a transparent insulating material are sequentially attached to the tip of the gun body 1, and a liquid sealing member 12 made of a heat-resistant elastic material such as heat-resistant rubber is attached.
is screwed onto the tip of the cylindrical body 11 through a mounting cover 13 in a fluid-tight manner. Reference numeral 15 denotes an arc shield member which is fitted and fixed in the recess 14 at the center of the tip of the liquid sealing member 12. The stud S is loosely inserted into the arc shield member 15 in the direction of arrow A, liquid-tightly penetrates a packing material 16 such as an O-ring disposed within the liquid seal member 12, and is bitten by the chuck 9. A movable core member 17 and a solenoid coil 18 surrounding it are housed together in a solenoid chamber 19 in a direction perpendicular to the longitudinal direction of the cylinder chamber 2, piston rod 8, and stud S. It communicates with the cylinder chamber 2. A sliding member 20 is attached to one end of the link 22 and is brought into sliding contact with the outer peripheral surface 3A of the piston 3. The link 22 is rotatably supported on the gun body 1 by a pin 21, and the other end is connected to the movable core member 17.

The piston 3 described above has one or more communication holes 23 passing through the front and rear, and a communication passage 24 connecting the front and rear of the piston 3 in the cylinder chamber 2 is provided inside the gun body 1. A regulating valve 25 that is manually operated from the outside is provided in the communication passage 24. The aforementioned cylinder chamber 2 and solenoid chamber 1
A plug 2 is provided in a part of the gun body 1 in the nine communication passages 24 and the space T inside the gun body 1 that communicates with these passages.
It is filled with an insulating liquid having corrosion resistance, such as oil, which is injected from an injection port 27 to which a screw 6 is screwed.

28 is a trigger provided on the gun body 1; 29 is a liquid-tight starting switch; 30 is a land-based power supply device; a welder including a control device; 31 is a control power source; 32, 33
34 is an electric wire for welding, 34 is an electrode protruding from the tip 35 of the stud S, W is a base material made of iron plate, stainless steel plate, etc., and G is a gas generating agent attached to the tip 35 of the stud S, according to the present invention. This is an important point. That is, the feature of the welding method according to the present invention is that a gas generating agent G is attached to the welded part surrounded by the liquid sealing member 12, and the gas generating agent G is thermally decomposed by arc heat to generate gas. , tip part 3 of stud S
5 is discharged to the outside of the liquid sealing member 12 by gas pressure, and welding is performed in an atmosphere free of water.

This gas generating agent G is, for example, a substance that generates an inert gas such as carbon dioxide at a relatively low temperature, such as sodium bicarbonate (NaHCO ₃ ) and aluminum (Al).
As a binder, it is kneaded with an epoxy resin at a certain ratio or wrapped in a waterproof membrane with sodium bicarbonate, and is attached to the tip 35 of the stud S in a water-insoluble state.

The thermal decomposition reaction of the gas generated by the gas generating agent G during arc welding is as follows.

6HaHCO ₃ +2Al→3Na ₂ CO ₃ +3CO ₂ +Al ₂ O ₃ +
3H ₂ This carbon dioxide gas (CO ₂ ) functions as an inert gas, and together with the simultaneously generated H ₂ , it increases the gas pressure and allows for good welding.

In this case, when about 400 mg of bicarbonate of soda is pyrolyzed, about 6/min of carbon dioxide gas is generated, which is sufficient for shielding the stud weld. Therefore, not only carbon dioxide gas but also gas generating agent G can be used if it generates inert gas at a rate of about 5 to 8 min.
Of course, it is not limited to bicarbonate of soda, but may be other materials.

Next, a method of welding using the welding gun of the present invention will be described.

As shown in FIG. 1, a gas generating agent G is attached to the tip 35 of the stud S which is held in the chuck 9 and protrudes from the arc shield member 15. On the other hand, in order to ensure the reliability of welding, a flux 36 in the form of a colloid, which does not decompose into water or melt, is applied to a portion of the base material W to be welded. (See Figure 2) Next, when the gun body 1 is pressed against the base material W at a right angle, the stud S is pressed in the direction of arrow A, causing the piston 3 to retreat in the same direction, and the liquid seal member 12 is compressed in the direction of the arrow B to tightly contact the surface of the base material W, and is surrounded by the arc shield member 15, the stud S, and the base material W in a narrow sealed space 37.
is formed. (See Figure 3) Next, when the trigger 28 provided on the gun body 1 is pulled to activate the liquid-tight starting switch 29, the control wire 31 connects the external power supply and actuating device. The welder 30 operates, energizes the solenoid coil 18 to attract the movable core member 17, presses the sliding member 20 against the outer peripheral surface 3A of the piston 3, and fixes the piston 3. On the other hand, welding electric wires 32, 3
3, when a weak welding current is passed between the base metal W and the stud S and at the same time the stud S is slightly separated from the base metal W, a pilot arc is generated.

The gas generating agent G is thermally decomposed by this arc heat, and for example, carbon dioxide and hydrogen are explosively generated.
The water in the sealed space 37 is discharged from between the liquid sealing member 12 and the base material W in the direction of arrow C by the gas pressure. (See FIG. 4) Next, the tip 35 of the stud S and the surface of the base material W are melted by arc discharge heat to generate molten metal 38. (See FIG. 5) At this time, the pressure inside the sealed space 37 increases due to arc discharge heat, molten metal heat, etc., so that water is prevented from entering.

After a certain period of time has passed, when the energization is stopped, the solenoid coil 18 is demagnetized, and the piston 3 released from the sliding member 20 moves forward in the direction of arrow D by the elastic force of the stud return spring 4, and the stud S moves toward the base material W. Welding is performed by the molten metal 38.
(Refer to Fig. 5), when the piston 3 moves back and forth within the cylinder chamber 2, the filled liquid flows into the communication hole 2.
3. The forward speed of the stud S by the stud return spring 4 is adjusted by moving the piston 3 back and forth through the communication path 24 and adjusting the opening degree of the regulating valve 25.

Welding work will be performed in this manner. The gas generating agent G described above may be attached to the tip 35 of the stud S and also to the surface of the base material W, but when a substance with a low decomposition temperature is used, it may be attached to the arc shield member 15 or the liquid seal. Member 12
It may also be attached to. Furthermore, the stud S is used as the base material W.
The present invention is also applicable to a stud welding method in which an arc is generated while the stud S is fixed at the set position shown in FIG. 3 without being removed from the stud S to generate an arc.

Effects of the present invention The tip part 35 of the stud S is surrounded by the liquid sealing member 12 so that a sealed space 37 is formed when it comes into contact with the base material W, and the gas generating agent G attached to the welding part is used for welding. The stud S is thermally decomposed by arc discharge heat, gas is generated, and the liquid (water) in the closed space 37 is discharged to weld the stud S to the base material W, so there is a greater degree of freedom in work compared to conventional techniques. Therefore, reliable welding can be performed. Since the liquid sealing member 12 is heat-resistant and elastic, it not only withstands welding heat and adheres closely to the surface of the base metal W, but also easily forms a gap for discharging water by gas pressure, so that welding is carried out in a state in which water is expelled. This allows for strong welding. Further, in the present invention, by generating an inert gas, an arc can be stably generated even in the presence of water, and reliable welding can be performed. Since it is only necessary to create the necessary narrow sealed space 37, the diameter can be reduced and studs can be welded at narrow intervals.

In addition, in the case of a welding gun, the internal space of the gun body 1 containing the position fixing and driving parts necessary for the stud is filled with a corrosion-resistant liquid, so that rain etc. do not penetrate into the gun body 1. In addition, by pressurizing and filling the liquid, there is a risk of electrical leakage due to water intrusion.
It can be used safely even if the structure does not take into account corrosion, electrolytic corrosion, etc.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a welding gun used in the welding method of the present invention, and FIGS. 2 to 5 are cross-sectional views sequentially showing the steps of the welding method of the present invention. 1... Gun body, 12... Liquid sealing member, S... Stud, W... Base material, G... Gas generating agent.

Claims (1)

[Claims] 1. The tip of the stud S is a heat-resistant elastic liquid sealing member 1.
2, a gas generating agent G is attached to the welding part, the liquid sealing member 12 is brought into contact with the base metal W, an arc is generated between the stud S and the base metal W by the welding current, and the gas is generated by arc discharge heat, etc. The feature is that the generating agent G is thermally decomposed to generate gas, the water around the tip of the stud S is discharged outside the liquid sealing member 12 by gas pressure, and the stud S is welded to the base material W. Method 2 of welding studs on land, in which the gas generating agent G is attached to the tip 35 of the stud S, as set forth in claim 1. Method 3 of welding studs on land, as claimed in claim 1. In the description of scope 1, method 4 for welding studs on land formed by kneading gas generating agent G with bicarbonate of soda, aluminum powder, and epoxy resin at a certain ratio, chuck 9 for biting stud S. The internal space of the gun body 1, which houses the coupled piston 3, stud return spring 4, and solenoid coil 18 that fixes the stud S in a predetermined position when welding current is applied, is filled with a liquid having corrosion-resistant and insulating properties. A stud welding gun suitable for use on land, characterized in that the liquid can move forward and backward of the piston 3.