JPH0330472B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a welding torch, and includes:
In particular, the present invention relates to a welding torch with improved durability and welding workability.

(Prior Art) Conventionally used welding torches have a structure in which an insulating member is screwed onto the collet at the tip of the torch body, and a metal (copper) nozzle is screwed onto this insulating member. There is.

(Problem to be Solved by the Invention) However, in this welding torch, the tip of the metal nozzle wears out during use, making it easy for welding spatter to adhere, and it is difficult to remove the spatter. There are disadvantages in that it requires interruption of welding work and a great deal of effort to remove firmly adhered spatter. Moreover, the adhering spatter may cause a bridge between the welding tip and the nozzle.
When the nozzle comes into contact with the workpiece during welding work, a short circuit occurs between the welding tip and the workpiece through the nozzle, causing damage to not only the nozzle but also the torch body. . This not only brings about economic losses due to damage to equipment, but also puts psychological pressure on workers who must always be aware of the short-circuit phenomenon described above during welding work. It is also a contributing factor.

In addition, even in automatic welding using robots, etc., whose application has been rapidly expanding in recent years, from the viewpoint of continuous work over a long period of time, spatter adhesion to the nozzle as described above and the accompanying Preventing damage to equipment has become an important technical challenge.

In order to prevent the above-mentioned drawbacks, it is conceivable to make the entire welding nozzle from a non-conductive material such as ceramic, but as is well known, ceramic is susceptible to breakage if it has notches or the like. Since this material is easy to use, even if a welding nozzle with a shape similar to that of a conventional one is formed using this material, it is considered to be extremely difficult to put it into practical use as it is.

Therefore, the present applicant filed an earlier application (Japanese Patent Application No. 1983-
No. 200573 (see Japanese Unexamined Patent Publication No. 60-92086)),
A support ring is screwed onto the tip of the welding torch, and a grip claw having an engaging protrusion is formed at the tip of the support ring, while a concave groove is formed around the outer periphery of one end of the ceramic nozzle member. We have proposed a welding nozzle having a structure in which the nozzle member is fixed to the welding torch by fitting the engaging protrusion into the groove.

Although this welding nozzle can eliminate the above-mentioned drawbacks, since the nozzle member is required to have high dimensional accuracy due to the use of the above-mentioned uneven fitting, the machining thereof requires a great deal of time. As a result, the disadvantage is that the nozzle member becomes expensive.

This invention was made in view of the above, and its purpose is to have a structure that is difficult to attract spatter, has good removability, can prevent the short circuit phenomenon described above, and can be manufactured at low cost. An object of the present invention is to provide a welding torch whose durability can be improved.

(Means for Solving the Problems) The welding torch of the present invention that meets the above object includes an insulating member attached to a collet portion on the tip side of the welding torch, and a cylindrical nozzle member attached to the tip side of the insulating member. and a holding means for fixing the nozzle member to the insulating member, the nozzle member being formed of ceramics, and having a concave groove having an arcuate cross section around one end thereof. At the same time, a radially outward protrusion is formed by fitting an elastic ring with a circular cross section into this groove, and the holding means is formed with an engagement surface that engages with the protrusion, and further includes an engagement surface that engages the protrusion. The present invention is characterized in that a pushing mechanism is provided between the insulating member and the holding means for pushing the engagement surface that engages with the protrusion toward the welding torch.

(Function) Since the nozzle member is used as described above and is made of ceramic, spatter is difficult to adhere to, and its peelability is good, and there is also a barrier between the chip and the object to be welded. It becomes possible to prevent short-circuit phenomena, and it becomes possible to improve the durability of the welding torch. Moreover, since welding can be performed with the nozzle member in contact with the workpiece, it is possible to prevent shield failure due to the influence of wind, and the arc length can be maintained constant, improving welding work efficiency. It becomes possible to do so.

Moreover, since the above structure is employed, the nozzle member is not required to have high dimensional accuracy, and the nozzle member and, by extension, the entire welding torch can be provided at low cost.

Further, since the nozzle member does not have an edge portion, defects such as cracks caused by stress concentration can be prevented.

(Embodiments) Next, specific embodiments of the welding torch of the present invention will be described in detail with reference to the drawings.

In FIG. 1, 1 is a welding torch main body, and a collet 2 is attached to the tip thereof.
An insulating member 3 is screwed onto the outer periphery of the collet 2. A cylindrical nozzle member 4 is attached to the tip of the insulating member 3, and a holding means is attached to the outer periphery of the insulating member 3. A retaining ring 5 is arranged. The insulating member 3 is provided with a threaded portion 6 on its inner periphery, and the inner threaded portion 6 is screwed onto the outer periphery of the collet 2. Further, a step 7 extending in the axial direction is formed at the tip of the insulating member 3, and one end of the nozzle member 4 is fitted into the step 7. Although not shown, it is assumed that a welding tip is attached to the tip of the collet 2.

The nozzle member 4 is a cylindrical member, and grooves 8, 8 are provided around the outer periphery near both ends of the nozzle member 4, respectively. A ring spring 9 is fitted into one of the recesses 8, and this ring spring 9 serves as a protrusion that engages with an engagement surface to be described later. Non-conductive materials such as ceramics are used to form this nozzle member 4, and among them, Si ₃ N ₄ and ceramics mainly composed of it have excellent high-temperature strength, abrasion resistance, and thermal shock resistance. It has been confirmed that this material is particularly preferable as a material for the nozzle member 4.
In addition, a test was also conducted using a nozzle member 4 made of Al _{2 O 3 in} addition to the above-mentioned Si ₃ N 4 etc., but the nozzle member 4 made of Si ₃ N ₄ etc. was far superior in terms of both the amount of spatter attached and the spatter removability. We are sure that it is excellent.

A recess 10 extending radially inward is formed in the insulating member 3, and a ball 11 is fitted into the recess 10. The ball 11 is biased radially outward by a spring 12 and is arranged so as to protrude from the outer circumference of the insulating member 3.

On the other hand, the retaining ring 5 has a through hole 13 into which the ball 11 provided on the insulating member 3 can fit, and a radially inward protrusion is formed at the tip thereof. The inner surface of this protrusion serves as an engagement surface 14 that can engage with the ring spring 9. In this case, as shown in FIG. 2, a plurality of through holes 13 are bored along the radial direction of the circumferential side of the retaining ring 5, and each through hole 13 is formed at a predetermined position in the axial direction. They are arranged with a difference of pitch P from each other. This pitch P is, for example, the ball 11
It is preferable to set P<(D-d)/2, where D is the diameter of the protrusion and d is the diameter of the through hole 13. The reason for this will be explained later.

The insulating member 3 may be entirely formed of an insulating material, but the point is that the insulating member 3 is made of an insulating material.
It is sufficient that the outer circumferential portion including the collector 1 is insulated from the collector 2, and it is not necessarily necessary that the entire portion be formed of an insulating material.

The welding torch described above is assembled using the following steps. First, the inner circumferential threaded portion 6 of the insulating member 3 is screwed onto the outer circumferential portion of the collet 2 of the welding torch main body 1, and one end of the nozzle member 4 is fitted into the stepped portion 7 provided at the tip of the insulating member 3. . In this state, the retaining ring 5 is fitted onto the outer periphery of the insulating member 3. In this case, rotate the retaining ring 5 and
1 is fitted into the optimal through hole 13. In this state, the engagement surface 14 contacts the ring spring 9 of the nozzle member 4, and the nozzle member 4 is pressed toward the torch 1 side via the ring spring 9, and is pressed within the stepped portion 7 of the insulating member 3. It will be held at

In the above-mentioned welding torch, the nozzle member 4 made of ceramic is arranged at the tip of the torch, so that it is difficult for spatter to adhere to it, and even if it does adhere, it can be easily peeled off, and furthermore, the chip and the object to be welded can be easily separated. It is possible to prevent a short circuit phenomenon between the welding torch and the welding torch, thereby improving the durability of the welding torch. Moreover, since welding can be performed with the nozzle member in contact with the workpiece, it is possible to prevent shield failure due to the influence of wind, and the arc length can be maintained constant, improving welding work efficiency. It becomes possible to do so.

In addition, because we adopted the mounting structure as described above,
Unlike conventional nozzle members 4, high dimensional accuracy is not required, machining becomes easy, and nozzle members 4, and by extension welding torches, can be provided at low cost.

Furthermore, as described above, since the structure is such that the ball 11 is fitted into the through hole 13, the nozzle member 4 can be attached in a so-called one-touch operation. Moreover, since the plurality of through holes 13 are arranged at the pitch P as described above, even if there are dimensional errors in each member, the ball 13 is always in the optimum condition.
1 can be fitted into the through hole 13. This is because although the arrangement of the through holes 13 is continuous, since the pitch P thereof is determined as described above, continuous positioning can be performed.

FIG. 3 shows a modification of the pushing mechanism for pushing the engaging surface 14 that engages with the protrusion of the nozzle member 4 toward the torch body 1 as described above. In place of the ball 11 and through hole 13, threaded portions 15 and 16 are provided on the outer periphery of the insulating member 3 and the inner periphery of the retaining ring 4, respectively.

FIG. 4 shows a modified example of the insulating member 3 and the retaining ring 5, which has a protrusion 17 on the outer periphery of the insulating member 3.
On the other hand, the retaining ring 5 is provided with a guide groove 18 into which the protrusion 17 is inserted. In this case as well, it is possible to hold the nozzle member 4 in the same manner as in the above embodiment. Note that the guide groove 18 may be provided at an angle as shown by a solid line in the figure, or it may be formed in a straight line like a groove 18a shown by a broken line in the same figure. In some cases, although not shown, a spring may be attached to the protrusion 17,
A structure may be adopted in which the nozzle member 4 is held using the elasticity of a spring.

FIG. 5 shows still another modification of the retaining ring 5. The retaining ring 5 in this case includes a cylindrical member 19 rotatably supported on the outer periphery of the insulating member 3;
It consists of a ring piece 20 screwed onto the inner periphery of the tip of this cylindrical member 19. By rotating the cylindrical member 19 or the ring piece 20, the ring piece 20 can be moved toward the torch 1 side via the screw. It has a structure that allows it to be moved.

FIG. 6 shows a modification of the retaining ring 5, in which the engaging surface 14 is formed in a tapered shape. By making the engagement surface 14 tapered in this way, the ring spring 9, that is, the nozzle member 4, is pressed and held not only in the axial direction but also in the radial direction, so that the nozzle member 4 can be held more easily. It becomes possible to hold it even more reliably. Note that in order to press and hold the nozzle member 4 inward in the radial direction as described above, the nozzle member 4 is integrally provided with a protrusion, and this protrusion is aligned with the engagement surface of the retaining ring 5. This is also possible by forming it into a tapered shape.

FIG. 7 shows a modification of the retaining ring 5. The retaining ring 5 in this case is composed of a cylindrical member 19 and a ring piece 20, similar to that shown in FIG. This structure is such that the nozzle member 4 is pressed and held inward in the axial direction and radial direction by the tapered surface 21.

Note that the nozzle member 4 in the first embodiment is provided with two grooves 8, 8 near both ends. Of course, it is also possible to provide the groove 8 only at one end so that it can be reversed and used again.

Although one embodiment of the welding torch of the present invention has been described above, the welding torch of the present invention is not limited to the above embodiment, and can be implemented with various modifications. For example, in the above example, the nozzle member is integrally formed of ceramics, but as shown in FIG.
A nozzle member may be used in which a ceramic layer 25 is formed on the inside and outside of the nozzle 4 by thermal spraying or the like. Alternatively, an elastic body such as a spring may be interposed between the protrusion and the engagement surface to absorb dimensional errors of each member and hold the nozzle member with its elasticity. be.

(Effects of the Invention) The welding torch of the present invention is configured as described above. Therefore, according to the welding torch of the present invention, spatters are difficult to adhere to, and its removability is also good. It becomes possible to prevent a short circuit phenomenon between the chip and the workpiece to be welded, and as a result, it becomes possible to improve the durability of the welding torch. Moreover, since welding can be performed with the nozzle member in contact with the workpiece, it is possible to prevent shield failure due to the influence of wind, and the arc length can be maintained constant, improving welding work efficiency. It becomes possible to do so. It has been confirmed that the average service life of the welding torch of this invention is several times longer than that of conventional nozzles. Moreover, since the nozzle member is not required to have high dimensional accuracy as in the past, machining becomes easy, and therefore the nozzle member, and by extension the welding torch, can be provided at low cost.

Furthermore, since the nozzle member does not have an edge portion, it is possible to prevent the occurrence of cracks caused by stress concentration, thereby improving the durability of the nozzle member and, by extension, the life of the welding torch as a whole.

[Brief explanation of the drawing]

Fig. 1 is a central longitudinal sectional view of an embodiment of the welding torch of the present invention, Figs. 2 a and b are explanatory diagrams showing an example of the arrangement of the through holes in the above, and Fig. 3 shows an example of a modification of the pushing mechanism. 4a and 4b are partial sectional views showing modifications of the insulating member and the retaining ring; FIG. 5 is a longitudinal sectional view of the main parts showing another modification of the retaining ring;
FIG. 6 is a vertical cross-sectional view of the main part showing still another modification of the retaining ring, FIG. 7 is a vertical cross-sectional view of the main part showing a modification of the retaining ring, and FIG. 8 is a modification of the nozzle member. FIG. DESCRIPTION OF SYMBOLS 1... Welding torch, 2... Collet, 3... Insulating member, 4... Nozzle member, 5... Holding member, 8
...Concave groove, 9...Ring spring, 11...Ball,
13...Through hole, 14...Engaging surface.

Claims (1)

[Claims] 1. The welding torch has an insulating member attached to the collet on the tip side of the welding torch body, a cylindrical nozzle member attached to the tip side of the insulating member, and a holding means for fixing the nozzle member to the insulating member, The nozzle member is made of ceramics, and has a concave groove with an arcuate cross section around one end, and an elastic ring with a circular cross section is inserted into the concave groove to create a diameter. A protrusion outward in the direction is formed, the holding means is formed with an engagement surface that engages with the protrusion, and an engagement surface that engages with the protrusion is formed between the insulating member and the holding means. A welding torch characterized by being provided with a pushing mechanism for pushing a mating surface toward a welding torch side.