Arc welding torch, replaceable wearing parts thereof and holder for replaceable wearing parts

Abstract

The present application relates to a replaceable wear part for an arc welding torch, the wear part being suitable for being arranged in the region of the end of the arc welding torch for carrying out a welding process, wherein the wear part is provided with threads on the outer side of a groove and / or on a boundary wall, and the heat transfer performance needs to be improved, and when such a component is energized, an improved current transmission performance also needs to be achieved. To this end, the present invention proposes that in the longitudinal direction of the wear part, toward the side or boundary wall, a conical first section having threads suitable for fixing the wear part is followed on or at the same side or boundary wall by a conical second section of the side or boundary wall without threads.

Description

Technical Field

[0001] The present invention relates to a replaceable wearing part of an arc welding torch, wherein the wearing part is particularly suitable for being arranged in an area of ​​the arc welding torch close to the end of a welding process, wherein the wearing part has a groove, which is preferably located in the center, and the groove is used to arrange another replaceable wearing part and / or for accommodating an electric welding rod and / or for conveying a shielding gas, and the outer envelope surface or boundary wall of the groove of the wearing part is provided with a conical section, which has a thread. Background Art

[0002] There are a large number of different welding processes. The invention is of particular significance for arc welding. Arc welding is based on the heating of an arc between an electrode and a workpiece to be welded. The workpiece to be welded can be locally melted by the heating. In almost all arc welding processes, a shielding gas is supplied to the area of ​​the arc in order, on the one hand, to achieve a reduced-resistance ionized atmosphere between the electrode and the workpiece and, on the other hand, to prevent oxidation of the electrode and the workpiece. Instead of an inert gas provided as shielding gas, an active gas or a mixture for the reaction can also be supplied. It is also possible to provide electrodes that do not require an external gas supply, since the required substances are contained in these electrodes and are released when the electrode melts.

[0003] Arc welding torches are usually designed in a way that allows a user or robot to direct a metal welding wire, also called a metal welding filler, to a desired joint point on a target metal piece. The welding wire is guided by the welding torch and ultimately delivered to the target metal piece through an opening in a contact nozzle at the end of the welding torch.

[0004] When voltage is applied to the inner tube of the welding torch and the welding wire contacts the target metal, a relatively high current flows from the inner tube of the welding torch via the so-called nozzle holder, via the contact nozzle, via the welding wire and, if necessary, via the arc to the target metal and to ground. The high current and the arc cause the welding wire to melt in the protective gas atmosphere, which causes the wire to form droplets and an arc to form.

[0005] This arc melts the metal of the target metal parts and the welding wire that is introduced further. The target metal parts are connected together because the resulting welding wire drops fall down or because the drops are transferred to the liquefied position of the target metal parts during a short circuit. Due to the small distance between the contact nozzle and the gas nozzle and the arc or the heated target metal parts, these components heat up significantly. Due to the high thermal load, the contact nozzle in particular is subject to severe wear.

[0006] Conventional welding torch systems generally consist of a contact nozzle, a nozzle holder and an outer gas nozzle at their ends. These components are mounted on the welding torch nozzle (outer tube, inner tube) and are thermally or electrically connected to each other via contact surfaces, threads, or coupled or insulated from other components of the welding torch nozzle. However, the outer tube must be electrically decoupled from other live components, because for safety reasons, no voltage should be present there. Through the thermal coupling of the components, an attempt is made to conduct the energy in the form of heat introduced into the contact nozzle or gas nozzle as effectively as possible through the outer tube or inner tube, thereby reducing the maximum temperature of the contact nozzle in order to minimize wear.

[0007] Conventional contact nozzles have an at least approximately cylindrical shape from the front end to the rear end, one end of which is provided with a cylindrical outer thread for fastening to a nozzle holder. DE-AS 2 334 335 discloses another contact or gas nozzle which, as an alternative to the cylindrical thread, has a conical end portion provided with a thread, which serves as part of a holding device for arranging the contact nozzle on a welding torch nozzle. It is mainly the end-side annular contact surface between the contact nozzle and the nozzle holder that serves as the contact surface for current transmission or heat transfer. In previously known solutions, the surface and thread provided there may not contribute significantly to the transfer due to the small contact area.

[0008] In general, the nozzle holder is mainly used as a support for the contact nozzle and for distributing the protective gas. The nozzle holder is usually connected to the inner tube by means of a thread. The nozzle holder can also be axially arranged on the inner tube by means of a flange. The end-side annular contact surface of the thread and the flange serves as a contact surface for current transmission or heat transfer.

[0009] The gas nozzle is normally fixed to the outer tube or to a component of the welding torch attached to the outer tube by means of an internal thread and is arranged axially thereon. The thread and the relatively small annular contact surface between the gas nozzle and the outer tube serve as a transfer surface for heat dissipation. An electrical insulator is usually provided between the gas nozzle and the nozzle seat. The thread of the gas nozzle serves primarily as a retaining device for fixing the gas nozzle to the outer tube.

[0010] Previously known contact nozzles that are all held in the arc welding torch, for example on a nozzle holder, and gas nozzles that are usually fixed in an exchangeable manner by means of a thread have the following disadvantages: even if they are set up for current transmission, the heat transmission and current transmission to the arc welding torch on other components in contact with them are still insufficient. The large current transmission resistance and the unfavorable heat transmission lead to temperature increases in the components that are usually used as replaceable wear parts. The high temperatures during the implementation of the welding process are in turn the cause of excessive temperature changes between the use of the arc welding torch and the non-use time, which in turn can often lead to accidental separation of the above-mentioned components. This can in turn be the cause of poor quality of the produced welded connection and malfunctions of the welding device. High temperatures can also lead to increased wear of these components, so that the service life is disadvantageously shortened. In addition to the increased costs of the wear parts themselves, additional increased costs are also caused by increased downtimes and more frequent maintenance operations for the arc welding torch and the automatic manufacturing equipment that optionally operates the arc welding torch. Summary of the invention

[0011] In view of this, the object of the present invention is to achieve an improved heat transfer performance when using an arc welding torch of the type mentioned in the introduction, wherein live components that can be connected in a detachable manner can also be provided in the arc welding torch. When such components are live, an improved current transmission performance should also be achieved.

[0012] In an arc welding torch of the type mentioned at the outset, the solution of the invention for achieving this object is that the conical or conical first section with the thread is followed by a non-threaded but also conical or conical second section of the envelope surface or the boundary wall in the direction of the longitudinal axis of the corresponding wear part, in particular (but not necessarily) in the direction of the free end of the welding torch, and the arc welding process is carried out on the welding torch. The conical or conical second section following the conical or conical first section with the thread can be used and function as a particularly effective heat transition zone and, as the case may be, as a current transition zone to other components of the arc welding torch. Unlike the conventional end-side contact surfaces or cylindrical contact surfaces that are constructed substantially perpendicular to the longitudinal axis of the corresponding wear part, the conical surface itself can still provide a larger contact surface under conventional manufacturing tolerances, which contact surface actually comes into contact with the surface of the contact object that is consistent with the conical surface of the corresponding wear part. Due to the increased contact surface and contact pressure per unit area, the current transmission and heat transfer between the components are improved, which helps to reduce the process temperature in the area of ​​the corresponding wear parts, while extending the service life of the wear parts and helping to increase the operating safety of the arc welding torch. The invention is suitable for arc welding torches for any welding process in which the required process temperature is generated by means of an arc ignited and maintained by electricity, and is independent of whether the welding process is carried out by means of a melting electrode or a non-melting electrode. Similarly, the invention is not limited to welding torches for supplying shielding gas to the welding point. The method of the invention can also be applied in arc welding processes without shielding gas. In particular, MIG, MAG, WIG, plasma welding, plasma cutting, cold wire welding processes, WIG / hot wire welding processes, laser / hot wire welding processes and laser / cold wire welding processes, etc., are all possible application areas of the invention.

[0013] In a preferred embodiment of the invention, a thread undercut can be provided between the first and second conical or tapered sections, the thread undercut having a smaller diameter than the unthreaded conical or tapered section. With this solution, the thread on the conical first section of the wearing part and the unthreaded conical second section can be manufactured particularly easily on an automatic lathe in series production. In this way, a wearing part having the properties and features of the invention can be manufactured particularly inexpensively.

[0014] According to the present invention, there may be a large contact force between the wear part and its support. Nevertheless, the preferred embodiment of the present invention still helps to enhance the shape stability of the corresponding wear part. In the embodiment, the cylindrical threadless equal-diameter section of the side or boundary wall preferably connects the conical threadless section of the side or boundary wall of the wear part along the longitudinal axis of the wear part, so that the threadless conical section is located between the threaded conical section and the cylindrical section. The cylindrical section can provide shape stability for the wear part similar to a ring anchor hook.

[0015] Furthermore, according to the invention, the two conical or conical sections can preferably have the same cone angle or cone angle, in particular a cone angle or cone angle that is constant over its entire longitudinal extension. This embodiment of the invention allows particularly simple production while achieving high operating safety. In an alternative embodiment of the invention, the two sections, each of which is provided with a cone, can also have different cone angles.

[0016] In a preferred embodiment of the invention, at least one of the two conical or conical sections of the wearing part can be provided with a certain cone angle, which is suitable for achieving self-locking with the material of the contact object component. In order to achieve this self-locking property, the cone angle suitable for the threaded and / or unthreaded conical section of the wearing part, which is smaller than the friction angle, can preferably be selected from an angle range of 5° to 15°, particularly preferably from an angle range of 8° to 12°, wherein the wearing part can preferably be made of the material copper or a copper alloy and / or when using a conductive coating.

[0017] The pitch of the thread of the first conical section can also be selected from a range within which, depending on the intended material of the thread and its mating thread, self-locking is produced in the thread. A suitable pitch for a metal thread can be selected, for example, from a range of 5° to 15°, particularly preferably from 8° to 12°. This measure also facilitates a press fit of the corresponding wearing parts, which does not separate even in the case of large and frequent temperature differences.

[0018] The properties of the wear part according to the invention are particularly advantageous when the thread of the first threaded section is designed as a trapezoidal thread. The trapezoidal cross section of such a thread allows particularly effective heat transfer due to the planar and not only linear or point-shaped contact with the surface of the thread and its mating thread, as well as particularly effective current transfer when current is also to be transferred via the thread. In this way, the temperatures and temperature differences that occur in the respective wear part can be kept extremely low, which is beneficial to the wear behavior and the achievable service life. According to the invention, the trapezoidal thread is used to achieve both favorable wear behavior and reliable current and heat transfer, thereby ensuring a high degree of process reliability.

[0019] The solution for achieving the above-mentioned object also consists in a support according to one embodiment and a support system according to one embodiment. In such a support system, which should include the wear parts of an arc welding torch and other components of the arc welding torch (the components are configured to accommodate the wear parts and arrange the wear parts in or on the arc welding torch), according to this aspect of the invention, just as the conical or conical threadless sections of the wear parts and the support should correspond to each other in order to form a flat abutment, the threads of the support and the threads of the wear parts should also correspond to each other in order to form a screw connection between the support and the wear parts. Due to the two conical or conical threadless surfaces that correspond to each other being flat against each other, a particularly large contact area can be achieved between the components while the retained wear parts are automatically centered relative to the support in or on the arc welding torch. This is particularly beneficial for the heat transfer from the wear parts to the support and thus for the heat to be removed from the welding process point. In the case where the wear parts are also live components of the welding torch, the large contact area also contributes to a particularly efficient current transmission with the lowest possible resistance. A resistance which is as low as possible in turn advantageously keeps the heating caused by the current transmission at a low level.

[0020] In the case where the tightening torque required for attaching the wearing part to its holder results in a high contact pressure per unit area between the threadless conical surfaces abutting against each other, this also particularly helps to achieve a press fit of the wearing part, which is unlikely to come apart even in the case of frequent large temperature changes and vibrations. The screw tension acting by the tightening torque in the screwed or threaded connection results in an increase in the contact pressure per unit area between the contact surfaces due to the conical contact surface, which makes it possible to particularly advantageously tension the corresponding wearing part and its holder against each other, thereby better preventing the connection from coming apart accidentally than in previously known arc welding torches.

[0021] Such a support system can be arranged in a particularly advantageous manner between a contact nozzle as a wear part, which can also be referred to as a gas flow nozzle, and a nozzle seat connected to the inner tube, which in this case assumes the function of a support for the contact nozzle. In this case, the contact nozzle preferably has an external thread arranged on a cone or a conical shape, which is constructed or arranged corresponding to the internal thread of the nozzle seat that can be screwed to the external thread, so as to achieve a screw connection between the two threads. As an alternative, the internal and external threads on the component can also be exchanged. In addition, the wear part constructed as a contact nozzle is provided with a conical second section that is preferably arranged relative to the thread at the smallest possible distance when viewed in the longitudinal direction of the contact nozzle, which section is threadless and suitable for flat contact on the corresponding conical shape of the nozzle seat in terms of shape and size. The thread on the conical section can preferably be provided with a smaller diameter, while the threadless conical shape is constructed on a section that has a larger diameter than the threaded section.

[0022] In another preferred embodiment, the nozzle itself can be constructed as a wearing part according to at least one embodiment of the present invention. In addition to the function of the support for the contact nozzle and the two conical or conical sections provided for this purpose, the nozzle seat can have another conical threaded first section and a non-threaded second section in the area of ​​its inner tube end, especially on the outer side and the envelope surface. These two sections should correspond to the conical threaded section and the conical non-threaded section of the end of the inner tube or the end piece, so that the nozzle seat is fixed to the inner tube used as a support by means of its thread and can be positioned in a self-centering manner by means of the conical or conical shape. Preferably, a trapezoidal thread, preferably a flat trapezoidal thread, can be provided as the thread of these two components arranged on each other in a separable manner. In this way, in this solution, while extending the service life of the nozzle seat, particularly advantageous heat transfer and current transmission can also be achieved.

[0023] Finally, the invention can also be used in conjunction with a gas nozzle which is located outside the welding torch nozzle and can be connected to the outer tube, in that the connection here is also realized by a conical thread, preferably a trapezoidal thread, which threads correspond to each other and can be screwed together. In addition, the gas nozzle should be equipped with at least one conical non-threaded section, which can be brought into contact with a conical section of the support of the outer tube corresponding to the above section in the use position of the welding torch nozzle. As in other wearing parts, here too, the internal thread or the external thread (and thus the non-threaded conical inner or outer surface) can be selectively provided either in the wearing part or on the support of the wearing part.

[0024] The present invention also provides a solution for achieving the above-mentioned object, which is a nozzle holder-contact nozzle system according to one embodiment and an arc welding torch according to some embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For other preferred technical solutions of the present invention, please refer to the claims, description and drawings.

[0026] The invention is explained in more detail with reference to the exemplary embodiments shown purely schematically in the drawings, in which:

[0027] Figure 1 is an exploded perspective view of an arc welding torch of the present invention;

[0028] Figure 2 for Figure 1 A longitudinal cross-sectional view of an end region of an arc welding torch;

[0029] Figure 3 for Figure 1 and Figure 2 A longitudinal cross-sectional view of a contact nozzle mounted in a nozzle holder;

[0030] Figure 4 A longitudinal sectional view of the end region of the inner tube in which the nozzle seat is arranged;

[0031] Figure 5 for Figure 2 An enlarged view of the end region of the arc welding torch;

[0032] Figure 6 A sectional view of a threaded region of one of the wearing parts and a holder of the wearing part in an arc welding torch. DETAILED DESCRIPTION

[0033] Figure 1 A preferred embodiment of an arc welding torch 1 of the present invention is shown. The arc welding torch 1 is suitable for use in an automatic welding machine, for example, a welding robot. The arc welding torch 1 is arranged on an end effector not shown in detail, and the end effector is movable in different spatial directions, preferably in all spatial directions, on any feed path. In this way, the end effector can move along with the arc welding torch on its feed path, and the arc welding torch can produce a weld on a workpiece. The arc welding torch can preferably be constructed in principle in the same manner as the arc welding torch disclosed in WO 2005 / 049259A1, wherein Figure 1 The difference is in the end region of the arc welding torch in the embodiment, which will be explained below. An unlimited rotation of the welding torch and a prevention of twisting of the welding cable during the rotational movement can be achieved by a not absolutely necessary but particularly preferred embodiment of the arc welding torch, in which the arc welding torch has an outer stator part and an inner rotor part and the welding medium is fed and supplied to the welding point at least approximately along and coaxially with the longitudinal axis of rotation of the welding torch and the end effector.

[0034] The arc welding torch 1 shown is a welding torch 1 that works according to the metal-shielded gas welding process. When using this welding torch, since the welding wire 7 is consumed during the welding process, the welding wire 7 melted during the welding process is continuously introduced into the set welding point. Among them, the welding wire 7 usually passes through the interior of the welding torch 1 together with its welding wire core 8a and insulation layer 8b, at least through the inner tube 2. In addition, the shielding gas is supplied to the welding point, and it is usually also passed through the inner tube 2. In the embodiment, the shielding gas is an inert gas, and in other embodiments of the present invention, active gas (or a mixture of the two) can also be supplied as shielding gas. In addition, in the embodiment, the current is directed to the welding point or process point on the free end 1a of the arc welding torch, and the current is used to ignite the arc at the welding point and maintain it during the welding process. Therefore, the arc welding torch 1 is used together with a welding power source not shown and a wire feeder not shown. In a preferred embodiment, the welding wire, the shielding gas and the current are supplied to the arc welding torch 1 at the power connection point 3 through a known welding cable, especially a coaxial welding cable. Subsequently, the shielding gas is introduced into the delivery line inside the welding torch 1 at the connection point 3 of the arc welding torch 1, so that the shielding gas is delivered from the connection point 3 to the free end 1a to the welding point. The current is also conducted from the welding cable through the arc welding torch 1 to the welding point or process point. The current is also conducted to the process point inside the welding torch, so that the outside of the arc welding torch 1 is free of current.

[0035] Thus, the arc welding torch 1 has a welding torch nozzle 5, which is equipped with an outer tube 6 and an inner tube 2 arranged in the outer tube 6 and arranged coaxially with this outer tube at a distance. The outer tube 6 is electrically insulated from the inner tube 2, so that there is no electrically conductive connection between the outer tube 6 and the inner tube 2. The outer tube 6 and the inner tube 2 extend from one end of the arc welding torch to the other end 1a of the arc welding torch. In the region of the end 1a, several replaceable wearing parts are arranged, which will be described in detail below.

[0036] exist Figure 1 , Figure 2 and Figure 5The exploded view and the cross-sectional view of the free end 1a region of the arc welding torch are shown in the figure. It can be seen from these figures that, mainly due to the high process temperature, the free end 1a region of the welding torch 1 is equipped with replaceable components, which are directly or indirectly connected to the outer tube 6 or the inner tube 2. These components on the end side of the welding torch are subject to more wear and therefore must be replaced regularly. For this purpose, separable connecting parts are provided between the components. In particular, they refer to the so-called nozzle seat 9, the contact nozzle 10 and the gas nozzle 11, which can all be called wearing parts. Among them, the nozzle seat 9 is fixed with its end 9a in the end 2a region of the inner tube 2. At the end position of the nozzle seat 9 on the inner tube 2, the end side of the end 9a of the nozzle seat 9 is arranged at a distance from the inner end side boundary wall of the end piece 2d of the inner tube 2. This ensures that the non-threaded and threaded sections can always abut with their corresponding mating surfaces. The nozzle holder 9 is detachably connected with one of the ends 10a, 10b of the contact nozzle 10 at its other end 9b, wherein the other end 10a, 10b of the contact nozzle is the inner end of the welding torch 1 or the welding torch nozzle 5. The hollow cylindrical gas nozzle 11 is coaxially arranged with the contact nozzle 10 and the nozzle holder 9 and spaced apart in the radial direction, so that a gas outlet 12 with a circular cross section from the welding torch nozzle 5 is generated between the inner side 11c of the gas nozzle 11 and the outer surface 9d of the nozzle holder 9 and the contact nozzle 10. In the welding torch nozzle 5, the gas outlet 12 is limited by the flange 13 of the nozzle holder 9.

[0037] Mainly as Figure 2 and Figure 3 As shown, the nozzle holder 9 is provided with a through groove 16, which extends from its inner tube side end 9a to its contact nozzle side end 9b. In the region of the inner tube side end 9a, an inlet 17 of the through groove 16 is constructed in a funnel shape, and then the through groove continues to extend in a cylindrical shape of constant diameter. Between the inner tube side end 9a and the contact nozzle side end 9b, the wall of the nozzle holder 9 is provided with a plurality of outlet grooves 18 distributed radially around the wall and passing through the wall from the through groove 16 in the radial direction. These outlet grooves are suitable for inputting the shielding gas passing through the inner tube 2 into the annular gas outlet 12 and from there to the end 1a of the welding torch nozzle 5.

[0038] In order to fix the nozzle holder 9 on the inner tube 2, the inner tube has an end piece 2d of the inner wall 2b with a central through-recess 2c, which expands in a conical or circular cone shape. The through-recess 2c is suitable for accommodating the welding wire in the welding wire core and for supplying shielding gas. This conical end piece 2d of the inner wall 2b is in turn provided with two sections 20, 21, wherein the first conical or circular cone section 20 is provided with an internal thread 22. Unlike the first conical section 20, the second conical section 21 adjoining in the end direction of the inner tube is unthreaded and provided with a substantially smooth surface 23. In the embodiment shown here, the two sections 20, 21 have the same cone angle or circular cone angle, wherein the threaded section 20 is provided with a smaller diameter and the unthreaded section 21 is provided with a relatively larger diameter.

[0039] For example Figure 6 As shown, a trapezoidal thread may be preferably provided as the internal thread 22 of the inner tube 2. In particular, Figure 5 As shown, the cylindrical through-groove 2c of the inner tube 2 transitions to the internal thread 22 with a shoulder 24. Thus, a larger diameter is provided in the first thread line of the thread root of the internal thread 22, which is greater than the diameter of the cylindrical through-groove 2c. Due to the conical or truncated cone shape of the first section 20 following the cylindrical shape of the through-groove, the diameter of the thread root increases axially toward the second conical section 21.

[0040] The trapezoidal internal thread 22, which is symmetrical in cross section, has straight side surfaces 27, 28. Preferably, a flat trapezoidal thread is provided for the internal thread 22. In an ideal case, the side surfaces 27, 28 are flat against the side surfaces 27a, 28a of the external thread of the nozzle seat 9, which are provided with the same side angle. In addition, it is preferred that the lead of the internal and external threads 22 is provided, which is dimensioned so that self-locking is formed by means of the material of the external thread as a threaded counterpart of the internal thread. This can be achieved in particular in the following way: the lead angle of the thread flank is less than the inverse tangent value of the sliding friction of the material combination of the internal and external threads. Preferably, self-locking can be formed both due to the cone angle or cone angle in the region of the first section 20 and due to the lead of the trapezoidal thread 22, taking into account the material combination used. The other threads to be described below can preferably be constructed in the same way in principle, and the internal and external threads can also be interchanged as appropriate.

[0041] The nozzle holder 9, which is detachably fixed to the inner tube 2, has a longitudinal extension extending along its longitudinal axis 30. When arranged on the inner tube 2, the longitudinal axis 30 of the nozzle holder 9 is aligned with the longitudinal axis 2e of the inner tube 2 and its through-cut groove 2c. The nozzle holder 9 also has a through-cut groove 16, for which the longitudinal axis of the nozzle holder 9 is the axis of symmetry. In the region of the inner tube-side end 9a of the nozzle holder 9 and its end face, the through-cut groove 16 is designed in a funnel shape, wherein the diameter of the opening of the through-cut groove is initially the same as or larger than the through-cut groove 2c of the inner tube 2 and then tapers to a smaller diameter.

[0042] In the center of the nozzle seat 9, with respect to the longitudinal axis 30, several outlet grooves 18 are arranged which are distributed around the circumference of the nozzle seat 9 and which penetrate the wall of the nozzle seat 9 radially outward from the through groove 16. In the other axial course of the through groove 16 of the nozzle seat 9, the through groove 16 tapers and initially has a section of constant diameter again. This section is connected by a conically widening end piece which extends almost to the nozzle-contacting outlet or end 9b of the through groove 16. The basic shape of this end piece, which can also be called a cone, is produced by the conical shape and the circular cross section. The technical solution of the inner surface which limits the through groove 16 to the region of the end 9b will be described in detail below.

[0043] With respect to the outer side or envelope surface of the nozzle seat 9, in a preferred embodiment, the first section 32, more precisely the section with the area with a smaller diameter, is provided with an external thread 34. This external thread 34 is provided as a threaded counterpart for the internal thread 22 of the inner tube 2. Therefore, the external thread 34 has the same cross-sectional shape and the same pitch as the internal thread 22 of the inner tube 2. Therefore, in the embodiment, a trapezoidal thread with a pitch that corresponds to the pitch of the internal thread 22 and is selected in such a way that self-locking is formed due to the material combination and the pitch. Similarly, the cone or taper of the first section 32, which is rounded in terms of cross section, is provided with the same cone angle or cone angle as the first section 20 of the end piece of the inner tube 2, which is implemented as a conical borehole wall. The same is true for the second section 33 of the side or envelope surface of the conical non-threaded second section 21 of the inner surface of the nozzle seat 9 and the inner tube 2 without a thread. The two thread-free surface sections are designed with regard to the provided material combination and the cone angle or taper angle in such a way that these corresponding cone angles are smaller than the friction angle, so that self-locking occurs.

[0044] On the outer side or envelope of the nozzle holder 9, a cylindrical section is connected to a non-threaded conical second section 33, and a flange-shaped ring 13 is connected to this cylindrical section, which is integrally connected to the nozzle holder 9 and is suitable for abutting against the end side of the inner tube 2 and against the sleeve-shaped insulating element 35. The sleeve-shaped insulating element 35 is sleeved on the inner tube 2. The circumference of the flange 13 is arranged opposite to the sleeve-shaped second insulating element 36, which is in turn embedded in the undercut of the inner surface 11c of the gas nozzle 11. The sleeve-shaped second insulating element 36 abuts against the end side of the outer tube 6 with one of its end sides. Therefore, the flange 13 closes the annular gas outlet 12 on the back side, so that a gas backflow opposite to the predetermined flow direction of the protective gas can be prevented. Therefore, the gas outlet is formed by the nozzle holder 9 and its flange 13, the contact nozzle 10, the sleeve-shaped second insulating element 36 and the gas nozzle 11. For example, a cylindrical section 37 of the side surface or envelope surface of the nozzle holder 9 in turn adjoins the collar 13 , which section then transitions into a conically or conically tapering end region of the side surface or envelope surface.

[0045] The end piece 39 of the welding torch end side of the borehole wall of the nozzle seat 9, which expands conically or conically, has at least two sections 40, 41 and is constructed in principle in the same way as the end piece on the nozzle seat side of the through groove 2c of the inner tube 2. The first section of the end piece 39 is provided with an internal thread 42. In the embodiment, this internal thread 42 is constructed as a single-line trapezoidal thread, the pitch and cross section of which correspond to the trapezoidal external thread of the contact nozzle 10 as a threaded counterpart. The trapezoidal internal thread preferably has a certain pitch, which leads to self-locking of the thread when taking into account the materials of the two threaded counterparts. In the embodiment, the material of the trapezoidal internal thread has copper, a copper alloy or a conductive coating, and the pitch of the trapezoidal internal thread is smaller than the friction angle.

[0046] A further conical or conical section 41 of the inner surface follows the threaded conical first section 40 towards the nozzle-contacting end of the nozzle seat 9, but is unthreaded and has a substantially smooth surface. In the exemplary embodiment, the taper angle of the threaded first section 40 corresponds to the taper angle of the unthreaded second conical section 41 of the end piece 39. In other exemplary embodiments, different angles can also be set for the taper or conical shape of the two sections 40, 41.

[0047] An area of ​​the end-side end of the contact nozzle 10 is arranged in the overall conical end piece 39 of the inner surface of the nozzle holder 9. Like the nozzle holder 9, the contact nozzle 10 is also designed as a longitudinally extending component, which (except for certain details on the contact nozzle 10) is designed rotationally symmetrically with respect to the longitudinal axis 43, wherein this axis of symmetry is simultaneously the longitudinal axis and the axis of symmetry of the through-hole 44 on the two end sides of the contact nozzle 10. On the nozzle holder-side end side of the through-hole 44 or through-hole recess, this through-hole or through-hole recess is designed in the shape of a funnel with a continuously decreasing diameter. When using a newly inserted contact nozzle 10 or a newly introduced welding wire into the welding torch, this funnel serves as an introduction aid for the welding wire and, if appropriate, as a centering aid for the welding wire core. The through-hole 44 has a constant diameter after the funnel, which is adjusted according to the size of the welding wire used. The inner tube 2 , the nozzle holder 9 and the contact nozzle 10 therefore together form a feed line for the welding wire in the center of the welding torch 1 , wherein the diameter of this feed line decreases continuously from the inner tube 2 to the nozzle holder 9 and then to the contact nozzle 10 .

[0048] The side surface or envelope surface 46 of the contact nozzle 10 has an end piece 47 of this surface in the region of its end on the nozzle seat side, which end piece can be divided into two sections 48, 49. A first conical or truncated cone section 48 with a smaller diameter on the end side extends from the end of the contact nozzle 10 in the direction of the other end of the contact nozzle 10, wherein the size of the diameter of the first section increases when viewed in this direction. The first section 48 is provided with an external thread 50 over its entire length, in the preferred embodiment a trapezoidal external thread, which corresponds in terms of its geometric dimensions, in particular its cross-sectional shape and lead, to the internal thread 42 on the contact nozzle side of the nozzle seat 9. The cone angle or taper angle of the first section 48 also corresponds to the cone angle or taper angle of the first section 40 of the end piece of the nozzle seat 9. The conical first section 48 of the contact nozzle 10 is followed by a conical second section 49 of the end piece 47 in the direction of the free end of the welding torch nozzle 5. This conical or truncated cone second section 49 is thread-free and is provided with an at least substantially smooth surface. The cone angle or taper angle of the two sections 48 , 49 of the contact nozzle 10 is preferably the same. It also corresponds to the cone angle or taper angle of the two sections 40 , 41 of the inner surface of the nozzle seat 9 .

[0049] In the preferred embodiment shown, a short undercut 52 is provided between the conical or conical first and second sections 48, 49 of the outer side 46 of the contact nozzle 10, viewed in the direction of the longitudinal axis 43. The diameter of this undercut 52 is smaller than the adjoining beginning of the second section 49. The diameter of the undercut 52 is preferably smaller than the maximum diameter of the first section 48 and smaller than the minimum diameter of the second section 49.

[0050] At the end of the second section 49 with its maximum diameter, the side or envelope surface 46 transitions to a cylindrical section 53 of the side 46. In the region of the free end 10b of the contact nozzle 10, the cylindrical section 53 of the side 46 is provided with a wrench face 54, i.e. a surface of the contact nozzle 10 that can be engaged in a shape-matched manner and grasped with the aid of a suitable tool. In an embodiment, the wrench face 54 is two flat portions of the cylindrical side 46, which extend over a portion of the cylindrical section 53 when viewed in the longitudinal direction. Therefore, in a preferred embodiment, the two flat portions or wrench faces 54 are two mutually parallel planar rectangular surfaces that are at least approximately arranged opposite each other, i.e. offset by 180° on the circumference. In other embodiments of the present invention, such wrench faces may also have any number and shape that achieves a shape-matched contact with the tool and transmits the torque to the contact nozzle 10. As Figure 1 As shown, the nozzle holder 9 also has such a wrench surface 55 for engaging a suitable tool.

[0051] The end of the inner tube 2, the contact nozzle 10 and the nozzle holder 9 are surrounded by a gas nozzle 11. Figure 2 As shown, the gas nozzle 11 is also elongated and has a first end 11a and an oppositely arranged second end 11b. The gas nozzle longitudinal axis 56 extends through the first and second ends 11a, 11b and is aligned with the longitudinal axis 43 of the welding torch 1 or the welding torch nozzle 5 and thus the contact nozzle 10 and the nozzle holder 9. The gas nozzle is conical at the first end 11a and becomes cylindrical towards the second end 11b on the outer tube side. The outer side 11d and the inner boundary wall 11c of the gas nozzle 11 are at least approximately parallel to each other.

[0052] The gas nozzle 11 has an internal groove in the area of ​​the first free end 11a, thereby forming a conical shape. Subsequently, in the direction of the second end 11b on the outer tube side, before the conical end piece 58 with two sections 59 and 60, the conical groove is changed into a cylindrical shape or a bore with an undercut 14. This geometric shape construction scheme is only exemplary. Other shape sequences can also be used. The cylindrical borehole is followed by a conical or conical section 59 with an internal thread 61 as the first section 59, wherein the internal thread 61 provided here is constructed as a trapezoidal thread. The lead and the cone angle or cone angle of the thread 61 are preferably selected so that it is smaller than the friction angle of any material or smaller than the inverse tangent value of the friction coefficient. Adjacent to this section is a threadless conical section as the second section 60. The cone angle of the second section is preferably equivalent to the cone angle of the first section 59, and is therefore also smaller than the friction angle between the materials in contact with each other. The second end 11 b of the gas nozzle ends in a shorter cylindrical section, into which the second section 60 merges.

[0053] The end of the outer tube 6 is provided with an end piece 63 whose outer surface or side surface corresponds to the end piece 58 of the inner surface of the gas nozzle 11. Starting from the free end of the outer tube 6, the end piece 63 of the outer surface has a first threaded section 64. The outer thread 66 is a trapezoidal thread, which corresponds to the trapezoidal inner thread 61 in terms of its geometry. The same is true for the cone angle or taper angle of the first section 64 of the outer tube 6, which also corresponds to the cone angle or taper angle of the first threaded section 59 of the inner surface of the gas nozzle 11. The second section 65 of the end piece of the outer tube 6 is again threadless and is constructed as at least a smooth surface. The cone angle or taper angle of the second section also corresponds to the cone angle or taper angle of the second section 60 of the end piece of the gas nozzle 11. The threadless conical section 65 is adjoined by a shorter end-side cylindrical section, the inner wall of which has the same radius as the end of the threadless conical section adjoining the cylindrical section.

[0054] Therefore, the end of the welding torch system which is detachably mounted on the gas-cooled or water-cooled welding torch nozzle 5 is mainly composed of the wear parts nozzle seat 9, the contact nozzle 10 and the gas nozzle 11. As mentioned above, in a preferred embodiment of the present invention, all the wear parts, that is, at least the nozzle seat 9, the contact nozzle 10 and the gas nozzle 11 are connected by contact surfaces, which are designed in the same way in terms of their basic structure. These contact surfaces are respectively located on the end piece of one of the outer side surfaces of the corresponding wear parts or the end piece 31, 39, 63 of the inner wall defining the groove. In order to connect with other wear parts or with the fixedly installed components of the arc welding torch, the corresponding wear parts have at least one first conical section and a second conical section which are preferably arranged as close to each other as possible. In any case, one of the two sections is equipped with a thread, which, together with the threaded mating parts of the other components, produces a threaded connection for the corresponding wear parts. All threads are preferably trapezoidal threads, and particularly preferably flat trapezoidal threads, and their pitch is preferably in the self-locking range.

[0055] The respective conical end piece preferably transitions into a cylindrical, threadless section of the respective wearing part. The cylindrical section adjoining the respective end piece and integrally connected thereto can preferably act like an annular anchor hook, thereby providing the respective component with dimensional stability in the case of high pressing forces against its contact object and high tightening torques of the threaded connection. The diameter of the adjoining constant-diameter cylindrical section is preferably greater than at least one of the two sections of the respective end piece. The cylindrical section acting similarly to the annular anchor hook preferably has a diameter that is the same as or greater than the maximum diameter of the two respective sections, and the cylindrical section adjoins the two respective sections as closely as possible. Particularly advantageous results can be achieved when the first section of the end piece is provided with the smallest diameter and carries the thread of the respective end piece. In this case, the second section has a larger diameter than the first section and should be threadless. The cylindrical section, which is preferably directly adjoining the second section, can again have a diameter that is at least equal to or greater than the maximum diameter of the second section. This maximum diameter of the second section preferably directly adjoins the cylindrical section. This structure can be provided both in the outer side and in the boundary wall of a recess in a wearing part or a holder of the arc welding torch, which holder is provided on the arc welding torch in order to exchangeably accommodate another component.

[0056] To provide the connection, each of the wearing parts can have, in addition to the threaded first section, a non-threaded conical surface or cone as a second section, which is suitable for a planar contact with the corresponding conical surface or cone of the contact object. Therefore, the threaded section and the non-threaded section of one of the wearing parts are preferably realized in one piece in the same component. Due to the conical shape of the transmission surface, the corresponding surface is increased relative to the cylindrical shape while the axial length remains unchanged. Due to the wedge effect of the cone, the contact pressure per unit area increases sharply, so that both heat transfer and current transmission are improved. Through the conical trapezoidal thread, the risk of automatic separation of the threaded connection due to process conditions is greatly reduced while maintaining the lead in the self-locking range. This is conducive to the press fit of the connection. In this way, the clamping in the cone is further strengthened. In addition, a suitable cone angle for the threaded first section and / or for the non-threaded second section, which is smaller than the friction angle of the material combination, also helps to form self-locking and thus helps to press fit the corresponding wearing parts.

[0057] Another advantage of the solution according to the invention is that the unthreaded conical surfaces, in particular, which abut against each other, allow the components of the end region of the welding torch nozzle to be centered with respect to the longitudinal axis of the inner tube 2. Since in the embodiment of the invention the respective cylindrical section adjoins all the conical sections located inside, preferably the unthreaded sections, the load on the components is minimized when the fitting is screwed in. In addition, the centering of the components contributes particularly advantageously to an increase in the area proportion of the components or wearing parts fixed to each other that are actually in contact with each other, thereby contributing to an increase in the contact pressure per unit area that is evenly distributed on the contact surface. This in turn leads to an advantageous heat transfer and current transmission, so that the thermal load of the respective wearing parts caused by process heat and current transmission is reduced. In addition to ensuring a higher process stability, the service life of the respective wearing parts can also be extended compared to known solutions.

[0058] Although the measures according to the invention, namely the provision of at least two conical sections, one of which carries a thread and the other of which has a substantially smooth surface, are advantageous for all components in the end region of an arc welding torch, they are particularly important for the so-called contact nozzle 10. The contact nozzle, which guides the welding wire in the MIG / MAG welding process and supplies it to the welding point, is subject to particularly high thermal loads and can therefore be subject to greater wear than other components in the end region of the welding torch nozzle and to an increased risk of wear-related failures.

[0059] Reference numerals list

[0060] 1 Arc welding torch 18 outlet groove

[0061] 1a Free end 20 First section

[0062] 2 Inner tube 21 Second section

[0063] 2a End 22 Internal thread

[0064] 2c Through groove 23 Smooth surface

[0065] 2b Inner wall 24 shoulder

[0066] 2d End piece 27 Side surface

[0067] 2e longitudinal axis 27a side surface

[0068] 3 Power connection point 28 Side surface

[0069] 5 Torch nozzle 28a side surface

[0070] 6 Outer tube 29 thread root

[0071] 7 welding wire 30 longitudinal axis

[0072] 8a Welding wire core 31 End piece

[0073] 8b Insulation layer 32 has a first section with external threads

[0074] 9 Nozzle holder

[0075] 9a End 33 Second segment

[0076] 9b Insulation layer 34 External thread

[0077] 9d Outer surface 35 Insulation element

[0078] 10 Contact nozzle 36 Insulation element

[0079] 10a End 37 Cylindrical section

[0080] 10b End 39 End piece

[0081] 11 Gas nozzle 40 first section

[0082] 11a End 41 Second section

[0083] 11b End 42 Internal Thread

[0084] 11c Inside 43 Vertical axis

[0085] 11d Outer surface 44 through-hole contact nozzle

[0086] 12 Gas outlet

[0087] 13 Flange 46 Side

[0088] 14 Undercut 47 End piece

[0089] 16 Through groove 48 First section

[0090] 17 Entrance 49 Section 2

[0091] 50 External thread 64 First section

[0092] 52 Undercut 65 Second section

[0093] 53 Cylindrical section 66 External thread

[0094] 54 Wrench face 67

[0095] 55 Wrench Flat

[0096] 56 Vertical Gas Nozzle

[0097] 58 End piece

[0098] 59 First Segment

[0099] 60 Second Segment

[0100] 61 Internal thread 62

[0102] 63 End piece

Claims

1. A replaceable wearable part of an arc welding torch (1), the replaceable wearable part being a nozzle holder (9), a contact nozzle (10) or a gas nozzle (11), the wearable part being suitable for being arranged in the region of an end (1a) of the arc welding torch (1) for carrying out a welding process, wherein the wearable part is provided with a thread suitable for fixing the wearable part on an envelope surface and / or a boundary wall of a groove, wherein: In the direction of the longitudinal axis (2e, 30, 43, 56) of the wearing part, the threads of the envelope surface or the boundary wall are arranged on a conical first section on different end pieces of the wearing part, and a conical non-threaded second section of the envelope surface or the boundary wall is adjacent to the same envelope surface or boundary wall, Characterized in that the unthreaded and equal-diameter cylindrical section of the envelope surface or the boundary wall adjoins the conical unthreaded second section of the envelope surface or the boundary wall of the wearing part in the direction of the longitudinal axis (2e, 30, 43, 56), so that the conical unthreaded second section is located between the cylindrical section and the conical first section provided with the thread, Wherein, starting from the end surface close to the conical first section, the diameters of the conical first section and the conical non-threaded second section gradually increase in the same direction toward the cylindrical section.

2. The wearing part according to claim 1, characterized in that Each end piece (31, 39, 47, 58, 63) of the envelope surface or boundary wall comprises the conical first section and the conical non-threaded second section.

3. The wearing part according to claim 1 or 2, characterized in that: A centrally located groove is also provided in the wear part for arranging another replaceable wear part and / or for accommodating a welding rod and / or for conveying a shielding gas, wherein the centrally located groove is limited by the dividing wall and has the conical first section and the conical non-threaded second section.

4. The wearing part according to claim 1 or 2, characterized in that: An undercut (52) is provided between the conical first section and the conical non-threaded second section. The undercut (52) has a smaller diameter than that of the conical non-threaded second section.

5. The wearing part according to claim 1 or 2, characterized in that: The tapered first section and the tapered unthreaded second section have at least substantially the same taper angle.

6. The wearing part according to claim 5, characterized in that The taper angle is constant over the entire longitudinal extension of the tapered first section and the tapered unthreaded second section.

7. The wearing part according to claim 5, characterized in that The cone angle is selected from the range of 5° to 15°.

8. The wearing part according to claim 1 or 2, characterized in that: The thread of the conical first section is designed as a trapezoidal thread or at least has a thread section designed as a trapezoidal thread.

9. The wearing part according to claim 8, characterized in that In the trapezoidal thread as an external thread, the ratio of the bottom width of the groove of the thread to the top width of the thread tooth is less than 1, and in the internal thread, the ratio of the bottom width of the groove of the thread to the top width of the thread tooth is greater than 1.

10. The wearing part according to claim 1 or 2, characterized in that: The lead of the thread is in the range of 5° to 15°.

11. The wearing part according to claim 1 or 2, characterized in that: At least two end pieces, one of which is constructed on the outer side of the wearing part, and the other end piece is constructed on the boundary wall of the groove of the wearing part, wherein the two end pieces are respectively equipped with the conical first section with the thread and the conical non-threaded second section of the side or the boundary wall suitable for fixing the wearing part.

12. A support for an arc welding torch for receiving replaceable wearable parts, the replaceable wearable parts being a nozzle seat (9), a contact nozzle (10) or a gas nozzle (11), the support being provided with threads on the envelope surface or the boundary wall of a groove, and having two conical sections on the same envelope surface or the same boundary wall of the groove, wherein the conical first section is provided with threads, and the section is closely connected to a conical non-threaded second section along the longitudinal axis direction of the conical first section, characterized in that: The threadless and equal-diameter cylindrical section of the envelope surface or the dividing wall is adjacent to the conical threadless second section of the envelope surface or the dividing wall of the wearing part along the longitudinal axis (2e, 30, 43, 56), so that the conical threadless second section is located between the conical first section provided with the thread and the cylindrical section, wherein, starting from the end face close to the conical first section, the diameters of the conical first section and the conical threadless second section gradually increase in the same direction toward the cylindrical section.

13. A support system for wearable parts of an arc welding torch (1), comprising a wearable part and a support of the arc welding torch, wherein the wearable part is a nozzle holder (9), a contact nozzle (10) or a gas nozzle (11), and the wearable part is suitable for being arranged in the area of ​​the end of the arc welding torch (1) where a welding process is performed, and the support is arranged in or on the arc welding torch (1) for fixing the wearable part on a thread in a detachable manner, and the thread is arranged on a conical or conical section of the support, characterized in that A wear part constructed according to any one of claims 1 to 11, wherein the threads of the bracket correspond to the threads of the wear part so as to form a threaded connection between the bracket and the wear part, and the tapered or conical section of the bracket corresponds to the tapered or conical section of the wear part so as to abut against each other in a planar manner.

14. The support system according to claim 13, characterized in that: A non-threaded section of a support for the wearing part, the non-threaded section being located axially between the thread and the opening of the groove, through which the wearing part can be introduced for fastening on the support.

15. The support system according to claim 14, characterized in that: The bracket is used for contacting the nozzle (10).

16. The support system according to any one of claims 13 to 15, characterized in that: The holder provided with at least two conical sections is a component of a component which is arranged inside the shielding gas welding torch.

17. The support system according to claim 16, characterized in that: The component is a nozzle holder (9) and the component part is a one-piece component.

18. The support system according to any one of claims 13 to 15, characterized in that: The bracket is provided with a through groove open at its two ends along the longitudinal axis (2e, 30, 43, 56), and the conical groove having the threaded conical first section and the conical non-threaded second section is a component of the through groove of the bracket. In addition, the bracket is also provided with at least one exhaust port extending radially from the through groove through the wall of the bracket.

19. The support system according to claim 18, characterized in that: The support is designed as a nozzle holder (9).

20. The support system according to any one of claims 13 to 15, characterized in that: The lead angle of the thread and / or the taper angle or cone angle of the wear part and the bracket form a self-locking between the wear part and the bracket through the taper angle or cone angle.

21. The support system according to any one of claims 13 to 15, characterized in that: The cylindrical section of the side surface or boundary wall of the support adjoins the conical second section without thread of the side surface or boundary wall of the support, so that the conical second section without thread is located between the cylindrical section of the support and the conical first section provided with the thread.

22. A nozzle holder-contact nozzle system for a shielding gas welding torch, wherein the nozzle holder (9) is suitable for being detachably fixed in the inner tube (2) of the shielding gas welding torch, wherein the nozzle holder (9) is provided with a through groove open at its two ends along the longitudinal axis (2e, 30, 43, 56), and the nozzle holder (9) also has a connecting component in the area of ​​its first end for being detachably fixed to the inner tube (2) of the shielding gas welding torch, and is provided with a conical groove at the second end facing the open end of the shielding gas welding torch, and the conical groove has an internal thread (42), characterized in that A contact nozzle (10) constructed according to any one of claims 1 to 11 above, wherein the internal thread (42) of the nozzle seat (9) corresponds to the external thread (50) of the contact nozzle (10) so as to form a threaded connection between the nozzle seat (9) and the contact nozzle (10).

23. An arc welding torch for an automatic welding machine, the arc welding torch being equipped with a melting or non-melting welding rod and a replaceable contact nozzle (10) as a holding element for the welding rod, characterized in that: The contact nozzle (10) according to any one of the preceding claims 1 to 11.

24. An arc welding torch for an automatic welding machine, the arc welding torch being provided with a melting or non-melting welding rod and a replaceable contact nozzle (10) as a holding element for the welding rod, the outer tube (6) and / or the inner tube (2) being arranged as a holder for another replaceable wearing part at the end side of the welding torch and being provided with an envelope surface or a boundary wall of a groove, the other replaceable wearing part being a nozzle holder (9) or a gas nozzle (11), characterized in that: In the direction of the longitudinal axis (2e, 30, 43, 56), a conical first section of the end piece of the envelope surface or the boundary wall having a thread suitable for fixing the corresponding wearing part is adjacent to a conical non-threaded second section of the end piece of the envelope surface or the boundary wall on the same envelope surface or the boundary wall, and the conical non-threaded second section is further adjacent to a non-threaded and equal-diameter cylindrical section of the envelope surface or the boundary wall in the direction of the longitudinal axis (2e, 30, 43, 56), Wherein, starting from the end surface close to the conical first section, the diameters of the conical first section and the conical non-threaded second section gradually increase in the same direction toward the cylindrical section.

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