Welding torch with integrated welding wire feed unit and cooling

Abstract

The invention relates to a welding torch (1) with an integrated welding wire feed unit (17), with efficient and simultaneously compact cooling of the welding torch (1) and of the welding wire feed unit (17). The welding torch (1) is characterised in that a cooling block (41) having a cooling block channel (47) passing through the cooling block (41) and an insulating body (50) having an insulating path channel (51) passing through the insulating body (50) are arranged in the torch housing (3) of the welding torch (1), in that the cooling block channel (47) and the insulating path channel (51) are either part of the torch housing feed line (42) or part of the torch housing return line (45), in that the insulating body (50) is made of an electrically insulating material, and in that a length of the insulating path channel (51) in the insulating body (50) is at least 50 mm.

Description

[0001] Welding torch with integrated welding wire feed unit and cooling

[0002] The present invention relates to a welding torch with an integrated welding wire feed unit and an electric motor, wherein the welding torch comprises a torch housing and a torch neck, and the electric motor is arranged in the torch housing, wherein a torch neck supply line and a torch neck return line for a coolant are provided in the torch neck, and the ends of the torch neck supply line and the torch neck return line located in the torch neck are connected to each other, wherein a torch housing supply line and a torch housing return line are provided in the torch housing, and the torch housing supply line is connected to the torch neck supply line and the torch housing return line is connected to the torch neck return line. The invention also relates to a welding machine with a welding power source and a welding torch according to the invention.

[0003] Welding torches for performing welding processes, particularly MIG (Metal Inert Gas) or MAG (Metal Active Gas) welding, are well known. In such welding torches, a welding wire is fed through the torch by a wire feed unit and moved towards the torch nozzle. The welding wire simultaneously serves as the welding electrode. An electrical welding lead is also supplied to the welding torch, carrying an electrical potential through which a welding current flows during the welding process. The welding torch typically includes a contact tube connected to the welding lead, which also carries the electrical potential. The welding wire makes contact with the contact tube in the welding torch, thereby transferring the electrical potential to the welding wire (the welding electrode).Between the electrical potential of the welding wire and the workpiece to be welded (to which an electrical return wire to the welding power source is connected), an electrical welding voltage is present, causing an arc to burn between the welding electrode and the workpiece. When the electrical welding circuit is closed by striking an arc, the welding current flows in the welding circuit. This is all, of course, well known.

[0004] A welding torch typically consists of a torch body and a torch neck. The torch neck is detachably connected to the torch body via a coupling, for example, a threaded connection with a union nut. The torch neck has the torch nozzle at one end and the torch neck-side part of the coupling, such as the union nut, at the other. Preferably, the torch body is made up of several parts, such as a torch base, a cover, control electronics, a torch holder, or a torch handle, etc. In a cooled welding torch, a coolant supply line and a coolant return line are also provided, extending into the torch neck.

[0005] Welding torches with an integrated welding wire feed unit are also known. In such welding torches, an electric motor is integrated into the torch housing, for example in the torch base body, which, together with a drive roller driven by the electric motor and a counter-pressure roller between which the welding wire is clamped, forms the welding wire feed unit.

[0006] There are a multitude of difficulties associated with such welding torches with integrated welding wire feed units.

[0007] A fundamental and all-encompassing problem lies in the fact that there is very little space available in the welding torch to integrate the welding wire feed unit. This is due to the fact that the welding torch must be as compact as possible and cannot be arbitrarily large.

[0008] Another problem is that the welding wire feeder often has to handle highly dynamic welding wire movements, requiring high rates of change in wire speed and, in some welding processes (such as Cold Metal Transfer (CMT) welding), also changes in the direction of wire movement at high frequencies. In a modern CMT welding process, for example, the direction of the welding wire speed (push / pull phases) changes at a frequency between 100 and 120 Hz. This places high demands on the electric motor of the welding wire feeder and requires high motor currents during operation. Consequently, the electric motor heats up considerably during operation, necessitating efficient cooling of the electric motor within the welding torch to prevent overheating.

[0009] Various cooling concepts for the electric motor are known from the state of the art.

[0010] In a simple design, the electric motor is cooled by thermal radiation into the surrounding environment. Cooling fins are typically provided on the welding torch to increase cooling capacity. US 2007 / 0119840 A1 teaches the cooling of an electric motor of the welding wire feed unit by thermal radiation into the surrounding environment. This type of cooling is sufficient for modern welding torches with integrated welding wire feed units, and more complex cooling concepts would only increase the complexity of the welding torch and its use. Other cooling concepts, for example, provide a separate cooling circuit for the electric motor of the welding wire feed unit. This is shown in JP 2021-164960 A and JP 2022-50815 A for a gaseous cooling medium. In JP 2022-50815 A, the welding torch also has a separate cooling circuit with a coolant for cooling the welding torch.In JP 2016-129465 A, the shielding gas for the welding process is used simultaneously to cool the electric motor of the welding wire feed unit.

[0011] US 2007 / 0119840 A1 also allows for the provision of additional cooling channels in the torch housing, particularly in the section housing the electric motor stator, through which a liquid or gaseous cooling medium is circulated. Separate cooling lines for the welding torch may also be provided, which may also extend around the section of the torch housing containing the electric motor stator.

[0012] Cooling with a gaseous coolant is less effective than cooling with a liquid coolant, especially when space for cooling channels is limited. Providing a separate cooling circuit for the electric motor is also complex and increases the effort required to operate the welding torch, as a separate cooling circuit is then needed for the electric motor, usually in addition to the cooling circuit required for the welding torch.

[0013] However, using a coolant as a cooling medium for the welding torch or the electric motor of a welding wire feeder presents another problem. The welding torch contains the electrical potential necessary for welding at many points, for example, at the contact tube in the torch neck, at the connection between the welding cable and the contact tube, and at the coupling for the torch neck. The coolant used to cool the welding torch inevitably comes into contact with parts of the torch where this electrical potential is present. This electrical potential is then transferred to the coolant and the cooling line that carries it. Therefore, care must be taken to ensure that the cooling line does not contact any other electrically conductive components of the welding torch, as this would also transfer the electrical potential to them.This could pose a safety problem because a user of the welding machine or welding torch might be able to touch such components that are at electrical potential. This could be countered by, for example, making such cooling lines electrically insulated. However, if, for example, a common cooling circuit were provided in the welding torch to cool the electric motor of the welding wire feed unit and the welding torch itself with a coolant, electrical insulation of a cooling line would not be sufficient because the electrical potential would also be transferred through the coolant. With cooling channels in the housing of the electric motor, which is usually made of metal, the electrical potential would be present on the housing and thus potentially also on other components in contact with the housing, with the aforementioned safety implications.

[0014] Furthermore, an electrical potential on the motor housing could also disrupt the function of the electric motor itself. While it would be possible to electrically insulate such cooling channels from the coolant, this would be extremely difficult and costly. This problem does not occur when using gas as the cooling medium because gas has a significantly lower electrical conductivity than a liquid and therefore acts as an electrical insulator.

[0015] Current efforts are focused on increasing the performance of the welding wire feed unit integrated into the welding torch, particularly on increasing the rate of change of the welding wire movement and / or the possible frequency of changes in the welding wire movement. This is only possible with more powerful electric motors, which in turn leads to even greater heating of the electric motor during operation of the welding torch. The resulting heat could no longer be dissipated by cooling through thermal radiation from cooling fins alone. Therefore, additional cooling is necessary. A separate cooling circuit for the electric motor is disadvantageous, as already explained above, and should therefore be avoided. The use of cooling gas as a cooling medium is also problematic because the necessary cooling with cooling gas is hardly feasible due to the confined and limited installation space within the welding torch.The use of coolant also causes difficulties, especially if separate cooling circuits for cooling the welding torch and the electric motor of the welding wire feed unit are not desired.

[0016] This creates a fundamental need for a welding torch with an integrated welding wire feed unit, with efficient and compact cooling of the welding torch and the welding wire feed unit.

[0017] This is achieved by arranging a cooling block with a cooling block channel through the cooling block and an insulating body with an insulating channel through the insulating body in the burner housing, the cooling block channel and the insulating channel being either part of the burner housing supply line or part of the burner housing return line, the insulating body being made of an electrically insulating material, and the insulating channel having a length of at least 50 mm, preferably at least 75 mm and particularly preferably at least 100 mm.

[0018] This design allows for compact cooling, as only one cooling circuit is required for cooling the welding torch and the wire feed unit. The cooling block also ensures efficient cooling because it allows for targeted cooling of the components subjected to the highest thermal loads, particularly the electric motor of the wire feed unit. Furthermore, the inventive design of the insulating body prevents any electrical potential from the torch neck being transferred to the torch housing via a coolant line in the welding torch and the coolant itself. This is what makes the cooling of the torch housing and torch neck with a single, series cooling circuit using a single coolant possible in the first place.

[0019] In a preferred embodiment, the burner housing comprises a burner base body, and the cooling block is designed as a separate component arranged on the burner base body, preferably on a motor housing of the burner base body to accommodate the electric motor. This makes it possible to design, construct, and arrange the cooling block in the burner housing for optimal cooling performance.

[0020] For the most compact design possible, the insulating body is attached to the cooling block, with a cooling block outlet opening provided on the cooling block, which is connected to an insulating body inlet opening on the insulating body.

[0021] Advantageously, the torch housing return line or the torch housing supply line and / or the cooling block can be at least partially manufactured as a single component using a 3D printing process, preferably from a copper-nickel-chromium alloy. 3D printing allows for a reduction in the number of individual parts of these components and thus also in the number of possible electrical connections between them. This reduces losses caused by electrical connections, thereby decreasing the heat generated in the welding torch. This also helps to make the cooling system more compact and efficient.

[0022] In a welding machine, it is advantageous if the welding torch is configured to transmit the electrical conductivity of the coolant, detected by a conductivity sensor in the torch, to a control unit of the welding power source. This control unit is then configured to limit the welding voltage based on the detected conductivity of the coolant. This provides an additional safety layer, ensuring that the length of the insulating channel provided in the insulating body is sufficient under all circumstances, and especially when using coolants that are not otherwise permitted or specified for use with the welding machine.

[0023] The present invention is explained in more detail below with reference to Figures 1 to 8, which show exemplary, schematic, and non-limiting advantageous embodiments of the invention.

[0024] Fig. 1 shows a design of a welding torch,

[0025] Fig. 2 shows the welding torch with the cover removed,

[0026] Fig. 3 shows the cooling concept of the welding torch according to the invention.

[0027] Fig. 4 shows an embodiment of a burner housing,

[0028] Fig. 5 shows an embodiment of the welding torch with cooling block and insulating body, Fig. 6 shows the cooling block, the insulating body and further lines in an embodiment according to the invention.

[0029] Fig. 7 shows a possible embodiment of the insulating body and

[0030] Fig. 8 shows a possible design of the cooling block.

[0031] Fig. 1 shows a typical embodiment of a welding torch 1 with a torch housing 3 and a torch neck 2. The torch neck 2 is detachably connected to the torch housing 3 by means of a coupling 4, as is usual. However, instead of a coupling 4, the torch neck 2 could also be permanently connected to the torch housing 3. The coupling is, for example, designed as a union nut 5 on the torch neck 2 and a corresponding thread 6 on the torch housing 3 (Fig. 2), but can also be designed in any other way.

[0032] The torch housing 3 comprises a torch base body 7. Furthermore, the torch housing 3 may include other components, such as a cover 8, a torch holder 9 for mounting the welding torch 1 on a welding robot, or control electronics 10. If the welding torch 1 is hand-held, the torch housing 3 may also include a torch handle instead of (or in addition to) a torch holder 9.

[0033] When used, the welding torch 1 is connected via a hose assembly 11 to a welding power source (not shown in Fig. 1), and optionally also to a shielding gas source and a coolant source (which could also be integrated into the welding power source or the welding system). The hose assembly 11 can include the electrical welding cable, a cable for the welding wire, a shielding gas line, as well as a coolant supply and return line, control lines, etc. The hose assembly 11 is usually detachably connected to the welding torch 1 via a hose assembly coupling 12. However, the hose assembly 11 can also be permanently connected to the welding torch 1.

[0034] In Fig. 2, the cover 8 has been removed and the torch neck 2 detached. This reveals the part of the coupling 4 (here a thread 6) attached to the torch housing 3. Connections are also visible: a welding wire connection 13, a coolant supply connection 14, a coolant return connection 15, a shielding gas connection 16, and control cable connections may also be present. A connection for the electrical welding cable may also be provided. Often, however, the part of the coupling 4 attached to the torch housing 3 (here the thread 6) is connected to the welding cable, so that this part is at the electrical potential of the welding cable when the welding torch 1 is in use. In this case, this part would be made of an electrically conductive material, such as brass. The electrical potential is then contacted by the torch neck 2, or by the contact tube in the torch neck 2.It can be seen here that the coolant in the coolant supply line, which is carried through the part of the coupling 4 (here a thread 6) arranged on the burner housing 3, would also be directly at the electrical potential of the welding line.

[0035] It is also possible that the electrical welding cable is routed through the coolant supply or return line from the welding power source to the welding torch 1. This is done to cool the electrical welding cable, through which a high electrical current flows from the welding power source to the welding torch 1 during operation. The electrical welding cable would then exit the coolant supply or return line within the welding torch 1, for example, in the torch housing 3, and could then be connected to the coupling part of the coupling 4 on the torch housing 3 (here, the thread 6).

[0036] Figure 2 also shows a partial illustration of a welding wire feed unit 17 integrated into the welding torch 1. A drive roller 18 and a pressure roller 19 are visible in Figure 2, between which a welding wire 20 (indicated by dashed lines in Figure 2) is passed when the welding torch 1 is used for welding. The drive roller 18 is driven by an electric motor 21 (indicated by dashed lines in Figure 2), which is arranged in the torch housing 3, usually in the torch base 7.

[0037] The cooling concept of the welding torch 1 according to the invention is explained below with reference to Figures 3 to 8, which show various views and different parts of an advantageous embodiment of the invention. Figure 3 shows the cooling concept in a schematic representation using the example of a welding machine 36. Figure 3 shows a welding machine 36 with a welding power source 30 and a welding power unit 31, which provides the welding current and voltage via an electrical welding cable 34 during welding. The welding cable 34 is connected to a welding torch 1 of the welding machine 36 and to a welding electrode 35. The (consumable) welding electrode 35 is formed by the welding wire 20, which is moved by a welding wire feed unit 17 integrated into the welding torch 1 in the movement required for the respective welding process.The welding power source 30 (or an external component thereof) may also include a wire supply drum 33 from which the welding wire 20 is unwound. The welding power source 30 (or an external component thereof) may also include a cooling unit 32, for example, a coolant reservoir with a pump. The cooling unit 32 is connected via a supply line 40 to a torch housing supply line 42 in the welding torch 1, specifically in the torch housing 3. The torch housing supply line 42 is in turn connected to a torch neck supply line 43, usually via corresponding connections in the coupling 4 between the torch housing 3 and the torch neck 2. The end of the torch neck supply line 43 is connected in the torch neck 2 to a torch neck return line 44 running in the torch neck.The torch neck return line 44 is in turn connected to a torch housing return line 45 in the welding torch 1, specifically in the torch housing 3, usually via corresponding connections in the coupling 4 between torch housing 3 and torch neck 2. The torch housing return line 45 is connected to the cooling unit 32 via a return line 46.

[0038] The supply line 40, the return line 46 and the welding wire 20 (and optionally other lines, such as a welding line 34) can, for example, be guided in a hose package 11, which is connected to the welding torch 1 via the hose package coupling 12, as indicated by dashed lines in Fig. 3.

[0039] To efficiently cool the electric motor 21 of the welding wire feed unit 17, a cooling block 41 with a continuous cooling block channel 47 is provided in the torch housing 3. The cooling block channel 47 of the cooling block 41 is part of the torch housing supply line 42 in the torch housing 3. The cooling block 41 is, of course, positioned in the torch housing 3 to ensure the most efficient cooling of the electric motor 21. The cooling block 41 can be a separate component or integrated into the torch body 7. In the latter case, the cooling block channel 47 would be integrated into the torch body 7. If it is a separate component, the cooling block 41 can also be made of a material with favorable heat transfer properties, for example, a copper-nickel-chromium alloy such as CuNiSiCr or CuNi2SiCr.The cooling block 41 could also be manufactured using a 3D printing process with a copper-nickel-chromium alloy, which is very advantageous with regard to the design possibilities of the cooling block 41.

[0040] This creates a cooling circuit with a coolant as the coolant, whereby the coolant is pumped from the cooling unit 32 via the cooling block 41 in the torch housing 3, the torch neck 2, and back again. Due to this serial cooling, one cooling circuit is sufficient for cooling the electric motor 21 and the torch neck 2, which reduces the effort required for cooling the entire welding torch 1.

[0041] However, this leads to the problem explained at the beginning: the electrical potential applied to the welding wire 20 (the welding electrode 25) (indicated by the arrow symbol in Fig. 3) would be transferred via the coolant to the cooling block 41, and thus also to the torch body 7, with the associated safety and functional problems. Therefore, it would not be sufficient to simply manufacture the torch housing supply line 42 in the torch housing 3 between the torch neck 2 and the cooling block 41 from an electrically insulating material, because the coolant itself is an electrical conductor.

[0042] To solve this problem, an insulating body 50 with an insulating channel 51 extending through the insulating body 50 is arranged in the burner housing 3, preferably in the burner base body 7 of the burner housing 3, wherein the insulating channel 51 is part of the burner housing supply line 42. The insulating channel 51 is arranged between the cooling block channel 47 and the burner neck 2, preferably between the cooling block channel 47 and the coupling 4 between the burner housing 3 and the burner neck 2.

[0043] The insulating body 50 is made of an electrically insulating material. This means that there is at least no electrical connection between an insulating body inlet opening 59 of the insulating channel 51 and an insulating body outlet opening 60 of the insulating channel 51. Preferably, the entire insulating body 50 is made of an electrically insulating material. The insulating body 50 thus electrically interrupts the burner housing supply line 42. For the purposes of this invention, electrically insulating material refers to materials with a high specific electrical resistance of > 10 Ω. 8This, and thus electrical non-conductors, is understood. The insulating body 50 is preferably made of a plastic. In principle, any electrically insulating plastic can be used. Depending on the manufacturing method, the plastic is preferably suitable for injection molding and / or welding (for example, for ultrasonic welding). Thermoplastic materials are preferably used. Manufacturing is advantageously carried out using an injection molding process because this is very beneficial with regard to the design possibilities of the insulating body 50. Manufacturing using joined, for example, ultrasonically joined, injection-molded parts is also possible.

[0044] To prevent the electrical potential of the welding line 34 (of the welding wire 20) from being transferred via the cooling liquid, it is additionally provided that the insulating channel 51 in the insulating body 50 has a length of at least 50 mm, preferably at least 75 mm, and most advantageously at least 100 mm.

[0045] During operation of the welding torch 1, an electrical leakage current flows through the coolant. A leakage current is an electrical current that flows under normal operating conditions in an unwanted current path, in this case, the coolant. The coolant has a specific electrical conductance G (inverse of the specific electrical resistance R). The relationship between the conductance G of the coolant in a coolant line and the electrical conductivity K of the coolant (a known material parameter of the coolant) is known to be given by G = - K - R, where R is the cross-sectional area A of the coolant line and I is the length of the coolant line.In the area of ​​welding equipment, the maximum permissible leakage current, for example due to safety regulations, is 10 mA at a voltage of 500 V (although the welding voltages during welding are usually significantly lower, by a factor of 10). This results in a required minimum resistance of the coolant of 50 kΩ. Assuming tap water as the coolant, an electrical conductivity K of a maximum of 1000 pS / cm (usually lower) can be assumed. Assuming a cross-sectional area of ​​the insulating channel 51 of 15 mm². 2If this were the case, the required length of the insulating channel 51 would be 75 mm to limit the electrical leakage current to 10 mA at a voltage of 500 V. However, cooling is usually not performed with conventional tap water, but with distilled water, which has an electrical conductivity K of only 20 pS / cm at most. Therefore, a significantly shorter length I of the insulating channel 51 would suffice for distilled water.

[0046] With a length of 50 mm for the insulating channel 51, you are on the safe side and can cover common coolants. This is particularly important because, as a manufacturer of welding equipment and welding torches, you have no control over which coolant is actually used.

[0047] The insulating body 50 with the insulating channel 51 prevents the electrical potential of the welding line 34 from being transferred to the torch base body 7 via the coolant and the torch housing supply line 42, and prevents an impermissibly high electrical leakage current from flowing.

[0048] In an advantageous embodiment, a conductivity sensor 48 (indicated by dashed lines in Fig. 3) is additionally provided in the welding torch 1, preferably in the torch housing 3, which determines the electrical conductivity K of the coolant used in the welding torch 1. Based on the geometry of the insulating channel 51 (cross-section, length), the maximum permissible welding voltage at which welding may be performed with the welding torch 1 can then be determined. A control unit 35 of the welding power source 30 can limit the welding voltage on the welding cable 34 accordingly. For this purpose, the measured electrical conductivity K can be transmitted from the welding torch 1 to the welding power source 30 via a control line.

[0049] Figures 4 to 8 show a possible constructive embodiment of a welding torch 1 according to the invention.

[0050] Fig. 4 shows an embodiment of the burner base body 7 with an integrated motor housing 55. The cooling block 41 could be an integral part of the motor housing 55, but is preferably a separate component attached to the motor housing 55. A plurality of cooling fins 56 are also provided on the burner base body 7 to additionally cool the burner housing 3 by thermal radiation to the surroundings via the cooling fins 56. To increase the cooling capacity of the cooling fins 56, the cooling fins 56 advantageously project from the burner base body 7 on at least three sides, preferably on all four sides.

[0051] The electric motor 21 is inserted into the motor housing 55 of the welding torch 1. It is advantageous to have as little gap as possible between the electric motor 21 and the motor housing 55 to increase heat transfer from the electric motor 21 to the motor housing 55. The electric motor 21 could, for example, be clamped in the motor housing 55. The electric motor 21 could also be pressed into the motor housing 55, for example, with a clearance fit. A sleeve made of a material with favorable heat transfer properties could also be provided between the electric motor 21 and the motor housing 55. Similarly, thermal paste could be applied between the electric motor 21 and the motor housing 55.

[0052] It is also advantageous to optimize the design of the electric motor 21 with regard to power loss, as this also reduces the heat generated. For example, the cross-sectional area of ​​the motor winding's wire can be designed with heat loss in mind. Besides the materials used and the permanent magnets employed, the copper fill factor of the motor winding of the electric motor 21 is known to significantly determine the electric motor's heat loss. The higher the copper fill factor, the higher the efficiency and the lower the heat loss.

[0053] The electric motor 21 can, of course, also be designed advantageously with regard to heat conduction. For example, the stator of the electric motor 21 can be vacuum-encapsulated, with the encapsulating compound having a high thermal conductivity, preferably greater than 1.5 W / mK. Ideally, the encapsulating compound should be free of air inclusions, as these can reduce the thermal conductivity. To increase the thermal conductivity of the encapsulating compound, ceramic particles, such as boron nitride, can be included in it.

[0054] Furthermore, the control and regulation of the electric motor 21 is important for the power loss. Here, attempts can be made to reduce the losses by using more continuous control signals compared to pulsed, discontinuous signals.

[0055] One could also concentrate the heat transfer point between electric motor 21 and motor housing 55 to ensure good heat transfer.

[0056] For example, thermal insulation caps could be inserted axially into the laminated core from both sides, spaced axially apart from each other in the center. This creates a central outer ring without insulation caps, for example with an axial length of a few millimeters, which rests against the motor housing 55 and ensures good heat transfer to the motor housing 55.

[0057] The electric motor 21 could also be designed with an encapsulated space between the rotor and stator, sealed off from the environment. Suitable sealing elements, such as O-rings, could be provided for this purpose. This could be achieved by placing a rotary encoder for position detection at one axial end and the encoder evaluation electronics or a cover at the opposite end. This encapsulated space could then be additionally purged with the protective gas to further enhance the cooling of the electric motor 21. In other words, this additional cooling takes place directly at the motor winding, i.e., where the heat is generated, and the heat is carried away from the encapsulated space by the gas flow.

[0058] In one possible embodiment with a separate cooling block 41, the motor housing 55 has a connection surface 54 for the cooling block 41 (Figs. 4 and 5). The cooling block 41 makes contact with this connection surface 54 as fully as possible to ensure good heat transfer. Thermal paste can also be applied between the two surfaces. Threaded holes for attaching the cooling block 41 are indicated in Fig. 4.

[0059] The cooling block 41 also includes a connection part 57 for connecting the burner housing supply line 42. This can be a separate component or integrated into the cooling block 41. A supply flow rate Kj is supplied via the connection part 57. n supplied. The cooling block 41 is shown individually in Fig. 8 in one possible embodiment (without connection part 57). In Fig. 8, a possible course of the cooling block channel 47 is shown with a dashed line.

[0060] The insulating body 50 with its insulating channel 51 connects to the cooling block 41 with its cooling block channel 47. A cooling block outlet opening 58 on the cooling block 41 (Fig. 8) is connected to an insulating body inlet opening 59 on the insulating body 50. The coolant exiting the cooling block 41 is thus directed into the insulating body 50. Fig. 7 shows the insulating body 50 in one possible embodiment. The insulating body 50 can be attached directly to the cooling block 41 because it is electrically insulating. Figs. 7 and 8 show, for example, holes or threaded holes for attachment.

[0061] In Fig. 7, the course of the insulating body channel 51 is indicated by dashed lines. The insulating body 50 is advantageously designed to maximize the length of the insulating body channel 51 within the available space.

[0062] The coolant exits at an insulating body outlet opening 60. A supply line 61 (as part of the torch housing supply line 42 in the welding torch 1) is connected to the insulating body outlet opening 60, which connects the insulating body 50 to the torch neck supply line 43, preferably via the coupling 4.

[0063] The insulating channel 51 extends within the insulating body 50 between the insulating body inlet opening 59 and the insulating body outlet opening 60. In this embodiment, the insulating body outlet opening 60 is fluidically connected to the burner neck supply line 43. The cooling block channel 47 extends within the cooling block 41 between a cooling block inlet opening 53 (for example, formed by the connecting part 57) and the cooling block outlet opening 58. The cooling block outlet opening 58 is fluidically connected to the insulating body inlet opening 59.

[0064] The burner housing return line 45 is also shown (at least partially), which is connected to the burner neck return line 44, preferably via the coupling 4.

[0065] In Figures 5 and 6, a connecting sleeve 62 is provided on the torch housing return line 45. In this configuration, it serves to electrically connect a welding line 34 routed in the coolant return line. A screw terminal 63 can be integrated into the connecting sleeve 62 to electrically connect the welding line 34 within the sleeve. The torch housing return line 45 between the connecting sleeve 62 and the coupling 4 can be electrically conductive, for example, as a component manufactured using a 3D printing process from a copper-nickel-chromium alloy. In this section, the torch housing return line 45 transmits the welding voltage and current to the coupling 4, which is made of brass, for example. From the coupling 4, the welding voltage and current can then be transmitted to the torch neck 2.However, a separate electrical line could also be provided.

[0066] A return flow rate K is supplied to the cooling circuit via the burner housing return line 45. ou t traced back.

[0067] Figures 5 and 6 also show a shielding gas line 65 through which shielding gas can be supplied to the burner neck 2.

[0068] Figures 5 and 6 also show an optional blow-off line 66, through which a pressurized gas, such as compressed air or shielding gas, can be connected to blow out the welding torch 1 and the torch neck 2, in particular for cleaning or before replacing the welding torch 1 or the torch neck 2.

[0069] In the embodiment shown in Figures 5 and 6, the burner housing return line 45, the shielding gas line 65, and, if present, the exhaust line 66 are integrated into a single component. This component can be made of a copper-nickel-chromium alloy, advantageously using a 3D printing process, as this increases design possibilities. This component can be attached directly to the insulating body 50, for example, by means of screw connections. Care must be taken, especially if the insulating body is electrically conductive, to ensure that this component does not touch either the cooling block 41 or the burner base housing 7, which is easily achieved through appropriate design. By using 3D-printed components, the number of electrical connections in the system is reduced to a minimum because the component can be manufactured in one piece or at least with only a few assembled parts.Every current transition causes electrical losses, which in turn generate heat in the welding torch. Particularly in the welding current path, significant heat losses typically occur during current transitions due to the high current densities. This can be largely avoided or at least reduced using components manufactured using 3D printing.

[0070] In the embodiment described above according to Fig. 3, the electric motor 21 is cooled first, followed by the torch neck 2 by the coolant. Thus, the cooling block 41 and the insulating element 50 are arranged in the torch housing supply line 42, and the cooling block channel 47 and the insulating section channel 51 are part of the torch housing supply line 42 in the welding torch 1. However, the cooling circuit can also be reversed, so that the torch neck 2 is cooled by the coolant first, followed by the electric motor 21. In this case, the torch housing return line 45 in Fig. 3 would become the torch housing supply line 42 in the welding torch 1, and the torch housing supply line 42 in Fig. 3 would become the torch housing return line 45. The cooling block 41 and the insulating element 50 would then be arranged in the torch housing return line 45, and the cooling block channel 47 and the insulating section channel 51 would be part of the torch housing return line 45 in the welding torch 1.The burner neck supply line 43 and burner neck return line 44 of the cooling circuit in the burner neck 2 would of course also be reversed, as would the supply line 40 and the return line 46. However, this would not change the invention.

Claims

Patent claims 1. Welding torch with integrated welding wire feed unit (17) with an electric motor (21), wherein the welding torch (1) comprises a torch housing (3) and a torch neck (2) and the electric motor (21) is arranged in the torch housing (3), wherein a torch neck supply line (43) and a torch neck return line (44) for a coolant are provided in the torch neck (2) and the ends of the torch neck supply line (43) and the torch neck return line (44) located in the torch neck (2) are connected to each other, wherein a torch housing supply line (42) and a torch housing return line (45) are provided in the torch housing (3) and the torch housing supply line (42) is connected to the torch neck supply line (43) and the torch housing return line (45) is connected to the torch neck return line (44), characterized in thatthat a cooling block (41) with a cooling block channel (47) extending through the cooling block (41) and an insulating body (50) with an insulating channel (51) extending through the insulating body (50) are arranged in the burner housing (3), that the cooling block channel (47) and the insulating channel (51) are either part of the burner housing supply line (42) or part of the burner housing return line (45), that the insulating body (50) is made of an electrically insulating material, and that the length of the insulating channel (51) in the insulating body (50) is at least 50 mm, preferably at least 75 mm, and particularly preferably at least 100 mm.

2. Welding torch according to claim 1, characterized in that the torch housing (3) comprises a torch base body (7), and that the cooling block (41) is integrated in the torch base body (7), preferably in a motor housing (55) of the torch base body (7) for receiving the electric motor (21).

3. Welding torch according to claim 2, characterized in that the insulating body (50) is attached to the torch base body (7), preferably to the motor housing (55) of the torch base body (7).

4. Welding torch according to claim 1, characterized in that the torch housing (3) comprises a torch base body (7), and that the cooling block (41) is a separate component arranged on the torch base body (7), preferably on a motor housing (55) of the torch base body (7) for receiving the electric motor (21).

5. Welding torch according to claim 4, characterized in that the insulating body (50) is attached to the cooling block (41), wherein a cooling block outlet opening (58) is provided on the cooling block (41), which is connected to an insulating body inlet opening (59) on the insulating body (50).

6. Welding torch according to one of claims 1 to 5, characterized in that an insulating body outlet opening (60) is provided on the insulating body (50), which is connected either to the torch neck supply line (43) or the torch neck return line (44) in the torch neck (2).

7. Welding torch according to one of claims 1 to 6, characterized in that the torch housing return line (45) or the torch housing supply line (42) is at least partially manufactured as a component produced using a 3D printing process, preferably from a copper-nickel-chromium alloy.

8. Welding torch according to one of claims 4 to 7, characterized in that the cooling block (41) is at least partially manufactured as a component produced by a 3D printing process, preferably from a copper-nickel-chromium alloy.

9. Welding torch according to one of claims 1 to 8, characterized in that a conductivity sensor (48) is provided in the welding torch (1) which is configured to detect the electrical conductivity of the coolant.

10. Welding machine with a welding power source (30) and a welding torch (1) according to one of claims 1 to 9, wherein the torch housing feed line (42) in the welding torch (1) is connected to a cooling unit (32) of the welding machine (36) via a feed line (40) and the torch housing return line (45) is connected to a cooling unit (32) of the welding machine (36) via a return line (46).

11. Welding apparatus according to claim 10, characterized in that the welding wire feed unit (17) is provided to feed a welding wire (20) through the torch neck (2) during operation of the welding apparatus (36), wherein the welding power source (30) is set up in the welding apparatus (36) to apply a welding voltage to the welding wire (20) via a welding line (34) during operation of the welding apparatus (36).

12. Welding machine according to claim 11, characterized in that the welding torch (1) is configured to transmit an electrical conductivity of the coolant detected by the conductivity sensor (48) to a control unit (35) of the welding power source (30) of the welding machine (36) and that the control unit (35) is configured to limit the welding voltage depending on the detected conductivity of the coolant.

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