JPS60154883A - Wire outlet part of automatic arc welding gun - Google Patents

Abstract

PURPOSE:To maintain the specified advancing direction of a welding wire and to decrease overheating in the power feed part in the welding wire outlet at the top end of an automatic welding gun and the wear in said part due to the wire by providing a heat-shield ceramic cover provided with a wire guiding hole to said feed part. CONSTITUTION:Ceramics which is less worn in a wire guiding hole 12 and withstands arc heat is used for a heat-shield cover 11 to be attached to a power feed part 10 and any shape thereof is satisfactory as far as the cover protects the top end of the part 10 against arc light and can be directly or indirectly attached to the power feed part in the outlet in such a way that the hole 12 can be surely held in the home position. Press-fitting, adhesion screwing, lock nut type of a flange part, bolting, etc. are applicable to the method for attaching the cover as far as the cover is prevented from being loosened by the oscillation of the hole 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement of the wire outlet section of an automatic arc welding gun, and the wire guide function of the conventional wire outlet power supply section is added to the guide hole of the ceramic heat insulating cover newly added to the front surface of the wire outlet section. By changing the direction of the wire, the direction of wire movement can be kept constant, reducing overheating caused by the arc in the power supply section and wear caused by the wire.

Conventionally, the can of an automatic arc welding machine has a wire power supply contact tip replaceably attached to the tip to serve as a wire outlet. The contact tip is a small piece of copper alloy with a wire passage and power feeding surface in the center, and is usually screwed into the tip of the can. It is preferable that the power supply position to the welding wire be as close to the arc generation position as possible. If the wires are separated, the wire will be preheated by the resistance heat of the large current flowing through the wire, and the arc heat will melt the wire more easily, resulting in shallower penetration and other unfavorable effects on the welding phenomenon. For this reason, the current model is established in which the most advanced contact tip of the gun serves both as a wire outlet and as a power supply.

This conventional type has a paradox in that the inner wall of the outlet, which is subject to the high heat of the arc and gradually wears out and deforms due to the sliding power supply to the wire, also takes over the role of guiding the wire. However, in actual work, the welding technology team operates the gun by hand, adjusts the position of the can appropriately even when it is fully automatic, continuously monitors the arc to match the welding line, and inserts the contact tip at the appropriate time. Since it was replaced with a new one, it did not affect welding quality. For this reason, the model containing the contradiction remains the standard model to this day. However, constant supervision by experts,
A device that requires adjustment is hardly a truly automatic device.

Arc welding using robots, which led to this invention, is difficult because the same welding line of parts of the same shape is repeatedly welded all day long, but after welding for three hours at a welding current of 500A, the contact tip of the welding gun must be replaced. Failure to do so may result in defective welding. At the very least, they wanted something that would allow them to install a new chip in the morning and not have to replace it until the evening.

Therefore, the first consideration was to prevent the outlet of the contact tip from becoming soft and prone to wear due to intense arc heat. Cooling was difficult, so a ceramic heat shield was placed over the chip. Instead of having a heat-blocking odor, the cover had a guide hole for the wire exit, which had a revolutionary effect.

Next, the configuration and embodiments of the present invention will be described with reference to the drawings, but before that, the wire outlet portion of a conventional gun will be explained with reference to FIG. 1 is the contact tip, ko is the tip of the welding gun, 3 is the encapsulated gas nozzle, gu is the @ pole wire, old is the base metal, 6 is the arc, 7 is the molten pool, and g is the welding line. It can be inferred at first glance that the wire outlet at the tip of the tip would be exposed to the high heat of the arc, accelerating wear.

The welding wire is unwound from the reel, passes through a simple straightening roller, and exits the tip/chip, but some curling remains. Therefore, a highly curved wire is forced into the tip, and the inlet, outlet, and intermediate portions of the tip are subjected to sliding friction, and the hot inner wall of the outlet is particularly abraded. If the outlet of the wire becomes slightly wider than a perfect circle due to wear, the position of the arc at the tip of the wire will deviate to the side from the weld line by several times that amount, resulting in a defective weld.

Now, this invention has a welding wire outlet power supply section at the tip of the gun.
It is characterized by being provided with a ceramic heat-insulating cover with wire guide holes, and an example thereof is shown in FIG. 2 and subsequent figures.

In this case, welding wire output and pasting at the tip of the gun, 10,
A sliding defrost tube similar to a conventional contact tip, screwed into the tip of the gun body. This power supply giBlθ
Ceramic heat shield cover with wire guide hole 1.2/
/ is screwed in.

Half of the screws /3 on the rear outer circumference of the supplied TIE Anatomy 10 are used to attach to the tip of the gun body, and the remaining half are used to attach the cover. Since the power supply part 10 is surrounded and reinforced by a heat-resistant and wear-resistant thermal cover, it may be thinner than a conventional contact tip.

After fully screwing the heat insulating cover into the power supply Hio in advance, grab the heat insulating cover and screw it onto the tip of the gun body until the open edge of the cover touches the main body. Power supply! This is a screw connection that can withstand the passage of large current between II and θ.

It goes without saying that the tip of the wire passage /q passing through the center of the power supply unit IO faces the guide hole /q of the heat insulating cover //. In principle, the wire passageway /4 (and the guide hole /2 are coaxial and have the same diameter, but in consideration of manufacturing errors, the diameter of the guide hole 12 may be made slightly larger. However, the guide hole The diameter should not be too large.

In addition, the length of the guide hole 7.2, that is, the thickness of the cover//bottom, should be kept as short as possible, taking into consideration the wear resistance of the ceramic material used, and within the range where the wear caused by the wire guide is negligible. make it thin. The larger the length and thickness of the wire, the more resistance heat will be added due to the welding current passing through the wire. Rather than using screws, the tapered surface /3α is tightened with a nut. Also, a screw /6 is made at the end so that the collar of the heat insulating cover // can be tightened and fixed with a nut /7. Is the heat shield cover// provided? Since the outer periphery of the a'-section 10 is tightened, it is securely fixed, and the guide hole /2 is held in place.

Thermal cover// is the power supply ffl! Any material may be used as long as it can function to block the arc light directed toward the power supply section 10 and to maintain a guide hole that will not wear out at the wire passage exit of the power supply section 10. Two embodiments in which a cover is attached to cover only the tip of the power supply section 10 are shown in FIG. 4.5.

The one in Figure 4 has a wrench on the power supply part IO in Figure 2.
Large diameter part with /! ;a is provided, and the heat insulating cover /l is a small one that covers only the tip portion of the power supply unit 10. The cover/l may be attached to the power supply unit 10 by adhesive, or the outer periphery of the power supply unit 10 may be roughened and the cover//l may be pushed in to form a static fit. As long as the cover// can be securely fixed to the power supply unit 10, any attachment method may be used. The embodiment of FIG. 5 replaces the conventional contact tip of FIG.
\, is used as the power supply part IO of this invention, and a ceramic cover // is glued to the tip. Alternatively, by adding various types of attachment means that are removable instead of adhesive, a conventional contact tip that is only replaceable can be transformed into a contact tube that can be used for a long time, and only needs to be replaced once in a while.

Even if the cover /l is small like the one in Fig. 5, the arc light comes from directly below t"t y, so it serves the purpose of shielding light. However, as in the embodiment shown in Fig. 2.5, the supply part 10
Power is supplied by reinforcing the entire length! l! 10
The material and dimensions can be made optimal only for the original power supply. Furthermore, the power supply unit 1O is not a "chip" that is a conventional replacement part, but can be a semi-permanent power supply unit.

Although a small number of embodiments have been described above, this invention is characterized by attaching a ceramic heat-insulating cover with guide holes to the wire outlet power supply part of the gun, and the wire outlet power supply part is similar to the conventional contact tip. It is limited to those with a circular hole power supply surface like this. For example, a clamping type sliding power feeding system is more preferable. The heat insulating cover that can be accessed over the wire guide hole is made of ceramic that has very little wear on the wire guide hole and can withstand arc heat. Any type of material may be used as long as it can be attached directly or indirectly to the outlet supply 11g so that it can be held in place reliably.

As mentioned above, the mounting method can be press fit, adhesive, screw fitting, flange tightening nut method, bolting, or other well-known mounting methods, but it must be such that it will not loosen due to vibration of the guide hole. Many.

This invention reveals a contradiction in the conventional wisdom that the wire outlet of an automatic arc welding gun is a contact tip. The inner wall near the exit of the contact tip, which is directly hit by the arc light, softens as the temperature rises and increases the electrical resistance, causing increased wear on the inner wall due to the curly wire. This is a contradiction.

This invention solves the above contradiction by adding a ceramic heat insulating cover with a wire guide hole to the gun outlet supply. Although the wire guide hole is subjected to the sliding friction of the wire, there is no wear accelerating effect due to minute sparks or resistance heat generation during sliding power supply, and it exhibits the wear resistance unique to ceramics.

Therefore, the direction in which the wire moves remains unchanged for a long period of time, eliminating the need for operators to monitor and adjust arc deviation. There is no longer any need to interrupt continuous work to replace the contact tip or remove adhering spatter.

The power supply part is protected from arc light by the heat shield, so
The synergistic effect of temperature rise and increase in electrical resistance disappears. Although the force pushing the power supply unit's active direction does not change due to the winding of the wire, the friction force is absorbed by the ceramic guide hole on the exit side, so the wear on the power supply exit side is minimal.

If well-known automatic arc control is added to an automatic arc welding gun to which this invention is applied, complete unmanned arc welding will become possible, similar to resistance welding. Extremely thick.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing an example of a wire outlet of a conventional automatic arc welding gun, and FIGS. 2.6.4.5 are explanatory views of four embodiments of the present invention. 10...Wire outlet power supply section, //...Heatproof cover. ward size

Claims (1)

[Claims] A wire outlet section of an automatic arc welding gun, characterized in that a ceramic heat-insulating cover with a wire guide hole is provided at the welding wire outlet power supply section at the tip of the gun.