Welding transformer and method for its production, method for production of modules for welding transformers

Abstract

The present invention relates to a welding transformer and a method of producing the same, a method of producing a module for a welding transformer. A welding transformer, a method for producing a module for a welding transformer, and a method for producing a welding transformer are provided. The welding transformer includes a core, at least one primary winding wound around the core such that the at least one primary winding is connectable with a power source to supply a primary voltage to the at least one primary winding, and at least two modules, wherein each of the at least two modules is formed as one component including at least one secondary winding wound around the core such that the at least one secondary winding is capable of converting the primary voltage into a secondary voltage for supplying a welding current to a welding tool, and a mounting unit for mounting a rectifier to the welding transformer to rectify the secondary voltage to supply a direct current as the welding current to the welding tool.

Description

TECHNICAL FIELD

[0001] The present invention relates to a welding transformer, a method for producing a module for a welding transformer and a method for producing a welding transformer. BACKGROUND

[0002] A welding transformer is used by a welding tool to provide a predetermined current to join metal parts of an object by at least one weld seam. For the generation of a weld seam, the welding tool can be guided by hand or by a robot. Usually, a transformer is attached to the welding tool to omit a heavy high-voltage cable. In this case, the weight and size of the transformer need to be optimized to make the handling of the welding tool easy. This also favors a low power consumption of the welding tool.

[0003] Such a light-weight welding transformer is usually connected with a rectifier. The transformer converts a primary alternating current into a secondary alternating current with a desired strength and time characteristic. The secondary side of the transformer is connected to a rectifier, which rectifies the current output from the transformer and provides a direct current to at least one welding electrode of the welding tool. If the welding electrode is brought into contact with a metal part and a corresponding welding current is fed to the welding electrode, a weld seam can be generated.

[0004] One problem is that the current generated by the transformer-rectifier unit generates a lot of heat. This requires the transformer-rectifier unit to be cooled, for example, by water as a coolant. Due to this, the transformer and the rectifier are usually made of a plurality of different parts to allow cooling of the unit and a compact size of the unit.

[0005] Another problem is that the plurality of different parts will be connected so that a sufficient stability is achieved to allow a safe operation for moving the welding tool around. In this context, a hard soldering is required, which leads to an oxidation of the parts that are soldered. Therefore, the parts have to be cleaned with effort.

[0006] All this makes the assembly of the transformer-rectifier unit rather complex. Therefore, the transformer-rectifier unit is expensive. SUMMARY

[0007] It is therefore an object of the present invention to provide a welding transformer, a method for producing a module for a welding transformer and a method for producing a welding transformer, which are able to solve the above-mentioned problems. In particular, it is an object of the present invention to provide a welding transformer, a method for producing a module for a welding transformer and a method for producing a welding transformer, which are able to simplify and enhance the assembly of the transformer-rectifier unit so that a light-weight transformer-rectifier unit can be built with high stability and low costs.

[0008] This object is solved by a welding transformer for a welding tool according to the features of claim 1. The welding transformer comprises a magnetic core, at least one primary winding wound around the core such that the at least one primary winding is connectable with a power supply to supply a primary voltage to the at least one primary winding, and at least two modules, wherein each of the at least two modules is formed as one component comprising at least one secondary winding wound around the core such that the at least one secondary winding is capable of transforming the primary voltage into a secondary voltage for supplying a welding current to the welding tool, and a mounting unit for mounting a rectifier to the welding transformer to rectify the secondary voltage to provide a direct current as the welding current to the welding tool.

[0009] In the described welding transformer, the number of metal components or modules is reduced to a minimum due to the absence of a separate secondary winding and a separate rectifier mounting unit.

[0010] A further advantage of the described welding transformer is that no hard soldering is required anymore. The modules are constructed such that a joint to the other components of the transformer can be formed by only fastening elements, like screws. Due to the reduced number of components, only a small number of joints to the fastening elements is created. Due to this, the construction of the transformer-rectifier unit is more stable than a transformer-rectifier unit having more parts, which require more joints to the fastening elements. Due to the reduced current losses, also a better efficiency is caused.

[0011] Thus, the above described welding transformer is constructed such that the assembly of the single components or modules of the welding transformer is easier than a transformer having a separate secondary winding and a separate rectifier mounting unit.

[0012] Further advantageous developments of the welding transformer are stated in the dependent claims.

[0013] Possibly, each of the at least two modules comprises a cooling liquid channel.

[0014] According to one configuration, the cooling agent channel comprises an opening for an inlet and / or an outlet of the cooling agent, wherein the opening is positioned between the at least one secondary winding and the mounting unit.

[0015] According to another configuration, each of the at least two modules comprises at least one blind hole and at least one through hole, which cross each other to form the cooling agent channel. Herein, at least one of the openings comprises a thread for sealing the cooling agent channel to the outside with a threaded plug.

[0016] The form of the secondary winding of one module can differ from the form of the mounting unit of the module.

[0017] In an advantageous configuration, the secondary winding of one of the modules is connected with the mounting unit of the module via a connector, which is positioned offset from the center line of the module.

[0018] It is conceivable that the welding transformer comprises a first module and a second module having the same outer form and / or shape, wherein the first and second module are positioned spaced apart from each other and side by side, such that the connector of the first module is positioned on the other side of the center line of the first module compared to the connector of the second module.

[0019] Possibly, the at least two modules are made of copper or aluminum.

[0020] In a particular configuration, each of the at least two modules is coated with a coating protecting the module from corrosion.

[0021] The welding transformer described above can be part of a welding tool for producing an article. The welding tool can further comprise a control unit configured to adjust a welding current for forming the article by joining at least two portions of one component and / or at least two components by at least one welding joint. In this context, the welding tool can further comprise means for moving the welding tool along at least one component according to a predetermined movement profile, wherein the article is a vehicle body.

[0022] The above-mentioned objects are further solved by a method for producing a module for a welding transformer according to the features of claim 13. The method comprises the steps of forming a plate-shaped module such that the module comprises a secondary winding and a mounting unit for mounting a rectifier to the welding transformer, and machining at least one blind hole and at least one through hole into the module such that the openings cross each other to form a coolant channel in the module.

[0023] The method achieves the same advantages as mentioned above with respect to the welding transformer.

[0024] The above-mentioned objects are further solved by a method for producing a welding transformer according to the features of claim 14. The method comprises the steps of positioning a first module laterally inverted with respect to a second module, wherein the first module and the second module at least have the same outer form, wherein each module comprises a secondary winding and a mounting unit for mounting a rectifier to the welding transformer, and wherein the first and second module are positioned such that the secondary windings of the first and second module are positioned facing each other, positioning and fastening at least two semiconductor modules between the mounting units of the first and second module to build a stack, wherein the at least two semiconductor modules are positioned in the stack on both sides of a central module of the rectifier.

[0025] The method can further comprise the step of mounting a core of the transformer into a recess of the secondary winding of the at least two semiconductor modules.

[0026] The method achieves the same advantages as mentioned above with respect to the welding transformer.

[0027] Even if not explicitly mentioned, further possible embodiments of the present application also include combinations of features or aspects described above or below with respect to the examples. In this context, the skilled person will also add individual aspects as improvements or additions to the respective basic form of the application.

[0028] A further embodiment of the present application is the subject of the examples of the present application described below. BRIEF DESCRIPTION OF DRAWINGS

[0029] In the following, the present application is described in more detail by means of examples and with reference to the accompanying drawings, in which:

[0030] Figure 1 A block diagram of a plant with a welding device according to an example is schematically shown;

[0031] Figure 2 A three-dimensional view of a raw module of a welding transformer for a welding device according to an example is shown;

[0032] Figure 3 A plan view of a first module realized after machining in the module of Figure 2 for cooling channels and openings for mounting is shown;

[0033] Figure 4 A plan view of a second module realized after machining in the module of Figure 2 for cooling channels and openings for mounting is shown;

[0034] Figure 5 A side view of an assembly of the first and second modules of Figure 3 and Figure 4 symmetrically positioned is shown;

[0035] Figure 6 A first side view of an assembly of the module of Figure 5 with components or modules of a rectifier is shown;

[0036] Figure 7 A second side view of an assembly of the module of Figure 5 with components or modules of a rectifier is shown;

[0037] Figure 8 A bottom view of an assembly of the module of Figure 5 with components or modules of a rectifier is shown;

[0038] Figure 9A flow chart is shown to illustrate a method for producing a module for a welding transformer; and

[0039] Figure 10 A flow chart is shown to illustrate a method for producing a welding transformer.

[0040] In the drawings, identical or functionally identical elements are provided with the same reference signs unless stated otherwise. DETAILED DESCRIPTION

[0041] Figure 1 A device 1 with a welding device 2 is shown very schematically. In particular, the welding device 2 is a resistance welding device. The device 1 is a production device for producing an item, such as a vehicle, a household device, a heater, etc.

[0042] In the device 1, metal parts 5, 6 can be connected such that a weld joint 7 is produced. To this end, the welding device 2 comprises a welding tool 10. The welding tool 10 is formed as a welding gun, which comprises two welding electrodes 11, 12, a control unit 20, a welding transformer 30 and a rectifier 40. In Figure 1 In the example, the welding tool 10 is moved by a device 50. The device 50 can be a robot.

[0043] The welding device 2 can produce the weld joint 7 with the welding tool 10 by control of the control device 20. In this context, for example, two edges of a single part 5 can be connected by one or more weld joints 7. Irrespective of the number of parts 5, 6 that are connected by the weld joint 7, the weld joint(s) can be produced by at least one spot weld or at least one seam weld or a combination of both.

[0044] The welding transformer 30 is mounted to the rectifier 40 such that a transformer-rectifier unit is provided.

[0045] The welding transformer 30 has a primary winding 31 and a secondary winding 32, which are both positioned at a common core 33. The primary winding 31 is connected to a power supply 25, which provides the necessary power and voltage U1 for welding, as indicated by the left arrow in Figure 1 The secondary winding 32 has three outputs 35, 36, 37 such that a first primary voltage U21 and a second secondary voltage U22 are produced. The first primary voltage U21 and the second secondary voltage U22 form a welding voltage U23, which results in a welding current I2 at the output of the transformer-rectifier unit. In the example shown, the welding transformer 30 is a medium frequency direct current transformer (MF-DC transformer).

[0046] In Figure 1In the example shown, the rectifier 40 has first to fourth semiconductor devices 41 to 44, for example transistors 41 to 44. The first semiconductor device 41 is connected to the first output 35 of the welding transformer 30. The second semiconductor device 42 is connected in series to the first semiconductor device 41. Thus, the series connection of the first and second semiconductor devices 41, 42 is connected between the transformer 30 and the welding tool 10. In more detail, the series connection of the first and second semiconductor devices is connected between the secondary winding 32 of the transformer 30 and the first welding electrode 11.

[0047] The second welding electrode 12 is connected to the second output 36 of the transformer 30.

[0048] The third semiconductor device 43 is connected to the third output 37 of the transformer 30. The fourth semiconductor device 44 is connected in series to the third semiconductor device 43. Thus, the series connection of the third and fourth semiconductor devices 43, 44 is connected between the transformer 30 and the welding tool 10. In more detail, the series connection of the third and fourth semiconductor devices 43, 44 is connected between the secondary winding 32 of the transformer 30 and the first welding electrode 11.

[0049] In the case that the semiconductor devices 41 to 44 are four transistors, the transistors 41 to 44 are switched under the control of the control unit 20 to switch the polarity of the welding voltage U23. Alternatively, the semiconductor devices 41, 42 can be replaced by one diode and the semiconductor devices 43, 44 can be replaced by another diode to provide a direct current as the welding current I2.

[0050] Figure 2 A raw module 34 is shown, which is configured to connect the transformer 30 and the rectifier 40. The raw module 34 is formed by one component. The component is made of metal, in particular copper or aluminum or at least one other metal which is able to conduct electricity. Copper and aluminum are advantageous in their comparably small electrical resistance as well as in their high thermal conductivity.

[0051] Possibly, the module 34 is coated by a coating 340, as Figure 2 is shown only very schematically in Fig. 1. The coating 340 can protect the modules 3401, 3402 from corrosion. For example, the coating 340 can be a coating for passivating aluminum or aluminum alloys, in particular the coating can be anodized. Alternatively, the coating 340 can be an electrocoating. Alternatively, the coating 340 can be a chemical coating of nickel. Alternatively, the coating 340 can be a cathodic dip coating. Alternatively, the coating 340 can be a plastic coating. Alternatively or in addition, the coolant can comprise a corrosion inhibitor.

[0052] The original module 34 has a plate-like form. The original module 34 has a secondary winding 341, a mounting unit 342, a connector 343, a recess 344, a first gap 345, and a second gap 346. The outer edge of the original module 34 can be circular.

[0053] The secondary winding 341 has a first end 3411 and a second end 3412.

[0054] The secondary winding 341 is wound around the recess 344, in which the core 33 of the transformer 30 will be inserted. In Figure 2 the example, the outer edge of the secondary winding 341 is inclined. Further, in Figure 2 the example, the recess 344 has an approximately square cross-section. The first end 3411 of the secondary winding 341 is connected with the mounting unit 342 by means of the connector 343. The second end 3412 is a free end of the secondary winding 341. In this context, the second end 3412 protrudes from the secondary winding 341 in the direction of the mounting unit 342. The second end 3412 is positioned facing the mounting unit 342. The second end 3412 is positioned spaced apart from the mounting unit 342 by means of the first gap 345. Thus, the first gap 345 separates the second end 3412 and the mounting unit 342.

[0055] In Figure 2 the example, the mounting unit 342 has an approximately rectangular cross-section. The mounting unit 342 is connected to the connector 343 at one of its four corners. The connector 343 is positioned offset from the midline M of the module 34. The midline M is approximately orthogonal to the axis of the recess 344.

[0056] In Figure 2 the example, the connector 343 has an approximately rectangular cross-section. In this context, the long side of the rectangular connector 343 is positioned transversely to the long side of the mounting unit 342.

[0057] The first gap 345 is delimited on one side by a portion of the long side of the mounting unit 342.

[0058] The connector 343 is positioned at least partially alongside the second end 3412. The second end 3412 is positioned spaced apart from the connector 343 by means of the second gap 346. Thus, the second gap 346 separates the second end 3412 and the connector 343. In Figure 2 the example, the second gap 346 is cascaded. Thus, the first end 3412 of the secondary winding 341 is also cascaded.

[0059] The second gap 346 is delimited on one side by a portion of the long side of the connector 343 and a portion of the secondary winding 341. The second gap 346 separates the connector 343 and the first end 3411 of the secondary winding 341. Further, the second gap 346 separates the first and second ends 3411, 3412 of the secondary winding 341.

[0060] The first gap 345 and the second gap 346 are connected to each other such that the gaps 345, 346 have an approximately angular or L shape. The gaps 345, 346 are to be filled with an electrically insulating material. In Figure 2 the electrically insulating material is air, such that the gaps 345, 346 are air gaps.

[0061] Figure 3 A plan view of a first module 3401 is shown, which is produced from the original module 34 shown in Figure 2 by machining first and second cooling channel openings 347, 348 for a cooling channel into the original module 34. The machining can be carried out by drilling as openings 347, 348. Figure 2

[0062] The first openings 347 are blind holes. The second openings 348 are through-holes. At least one of the openings 347 is provided with a thread 3471 at its opening end. Also, the openings 348 are each provided with a thread 3481 at their opening ends. In addition, third openings 349 are provided in the mounting plate 342 for mounting the rectifier 40 and the module 34 to each other. At least one of the openings 349 is provided with a thread 3491 at its opening end.

[0063] The openings 347, 348 of the first module 3401 are positioned transversely to each other such that at least two of the openings 347, 348 cross each other. Thereby, a cooling channel is built by the module 3401.

[0064] Figure 4 A plan view of a second module 3402 is shown, which is produced from another original module 34 shown in Figure 2 by machining first and second cooling channel openings 347, 348 for a cooling channel into this original module 34. As in the module 3401 shown in Figure 2 Figure 3 Figure 4 ​​​The first opening 347 of module 3402 is a blind hole. The second opening 348 is a through hole. At least one of the openings 347 has a thread 3471 at its opening end. Furthermore, each of the openings 348 has a thread 3481 at its opening end. Additionally, a third opening 349 is provided in the mounting plate 342 for mounting the rectifier 40 and module 34 to each other. At least one of the openings 349 has a thread 3491 at its opening end.

[0065] The openings 347 and 348 of the second module 3402 are positioned laterally to each other, such that at least two of the openings 347 and 348 intersect each other. Thus, a cooling channel is constructed through module 3402.

[0066] Therefore, the first and second modules 3401 and 3402 have the same external form and / or shape. However, as from Figure 3 and Figure 4 It can be concluded that the openings 347 and 348 for the cooling channels can be different for the first and second modules 3401 and 3402.

[0067] To assemble transformer 30 and rectifier 40, modules 3401 and 3402 are as follows: Figure 5 The locations shown are positioned relative to each other.

[0068] As from Figure 5 Therefore, the first module 3401 and the second module 3402 are positioned spaced apart from each other and side by side. Figures 2 to 4 Combination, from Figure 5 It is evident that, compared to connector 343 of the second module 3402, connector of the first module 3401 is positioned on the other side of centerline M of the first module 3401.

[0069] In other words, such as Figure 5 As shown, modules 3401 and 3402 are positioned symmetrically to each other, but laterally reversed relative to each other within transformer 30. In other words, the first and second modules 3401 and 3402 are rotated approximately 180° relative to each other, that is, around... Figure 2 The center line M of one of the modules 3401 and 3402 shown is perpendicular to each other. Therefore, the windings 341 of modules 3401 and 3402 face each other. Furthermore, the mounting units 342 of modules 3401 and 3402 face each other. However, the connectors 343 of modules 3401 and 3402 are positioned on two different sides of the stack constructed from modules 3401 and 3402.

[0070] according to Figures 6 to 8The rectifier 40 and the modules 3401, 3402 can be mounted as one unit. In this unit, the openings 347, 348 are sealed by a seal 3405 or a plug 3473. Thereby, the openings 347, 348 are closed such that no coolant can leak from the modules 3401, 3402. Thus, coolant can circulate in the modules 3401, 3402 to perform heat dissipation from the unit built by the transformer 30 and the rectifier 40. The coolant can be any suitable coolant, e.g. a fluid and / or a gas, in particular water or oil or air.

[0071] As shown in Fig. 3, the rectifier 40 comprises a contact unit 45 for connecting to the positive pole and a contact unit 46 for connecting to the negative pole. The contact units 45, 46 are configured to deliver the welding current I2 to the welding electrodes 11, 12. Figure 6

[0072] The rectifier 40 further comprises a first welding semiconductor module 401, a second welding semiconductor module 402, a central rectifier module 403, a first spring package module 404, a second spring package module 405 and a fastening device 408 having an end portion 409. As shown in Fig. 3, the modules 401 to 405 are stacked together with the modules 3401, 3402. The stack built by the modules 401 to 405 and the modules 3401, 3402 is fastened with the fastening device 408. To this end, the fastening device 408 is inserted through the opening 349 in all modules 401 to 405, 3401, 3402. In this context, the spring package modules 404, 405 perform a spring force to provide a pressure or holding force which holds the stack built by the modules 401 to 405 together. Figures 6 to 8

[0073] The first welding semiconductor module 401 is positioned between the first module 3401 and the center plate 403. The first welding semiconductor module 401 can comprise the semiconductor devices 41, 42 of the circuit shown in Fig. 1. Alternatively, the semiconductor module 401 comprises diodes for rectifying the voltage U21 shown in Fig. 2. Figure 1 Figure 1 The second welding semiconductor module 402 is positioned between the second module 3402 and the center plate 403. The second welding semiconductor module 402 can comprise transistors as semiconductor devices 43, 44 of the circuit shown in Fig. 1. Alternatively, the semiconductor module 402 comprises diodes for rectifying the voltage U22 shown in Fig. 2.

[0074] The second welding semiconductor module 402 is positioned between the second module 3402 and the center plate 403. The second welding semiconductor module 402 can comprise transistors as semiconductor devices 43, 44 of the circuit shown in Fig. 1. Alternatively, the semiconductor module 402 comprises diodes for rectifying the voltage U22 shown in Fig. 2. Figure 1 Figure 1 The second welding semiconductor module 402 is positioned between the second module 3402 and the center plate 403. The second welding semiconductor module 402 can comprise transistors as semiconductor devices 43, 44 of the circuit shown in Fig. 1. Alternatively, the semiconductor module 402 comprises diodes for rectifying the voltage U22 shown in Fig. 2.

[0075] ​​​​The first spring-packaged module 404 is positioned spaced apart from the first solder semiconductor module 401. The second spring-packaged module 405 is positioned spaced apart from the second solder semiconductor module 402. Therefore, the stack of rectifiers 40 includes, in this order, the first spring-packaged module 404, the first module 3401, the first solder semiconductor module 401, the central rectifier module 403, the second solder semiconductor module 402, the second module 3402, and the second spring-packaged module 405.

[0076] like Figure 7 As shown, by Figure 3 and Figure 4 The cooling channels formed by openings 347 and 348 in modules 3401 and 3402 are sealed to the outside of modules 3401 and 3402 by seals 3405. The openings 347 with seals 3405 can serve as inlets or outlets for coolant channels. Each of the seals 3405 is used to seal the corresponding winding 341, thereby preventing coolant leakage from the coolant channel. The openings 347 with seals 3405 are positioned between at least one secondary winding 341 and the mounting unit 342. The openings 347 with seals 3405 are positioned in the second end 3412 of the secondary winding 341.

[0077] The contact unit 46 for connection to the negative electrode is configured to connect to the cooling channel at the opening 347, which is... Figure 5 and Figure 7 The seal shown is 3405.

[0078] Apart from Figure 6 and Figure 7 In addition, Figure 8 A fastening device 410 for securing the contact unit 46 to the rectifier 40 is also shown.

[0079] Figure 9 The diagram illustrates, in a very schematic way, the materials used for production. Figure 3 The module 3401 shown or Figure 4 The method of module 3402 shown.

[0080] The method has a step S1 in which the original module 34 is integrally constructed. In this document, the original material is formed such that... Figure 2 As shown, the original module 34 has a winding 341, a mounting unit 342, a connector 343, recesses, and gaps 345 and 346. The original module 34 can be constructed by cutting the winding 341, mounting unit 342, connector 343, recesses, and gaps 345 and 346 from raw material, as shown. Figure 2The cutting can be performed by a laser or as a water cut. Alternatively, the original module 34 can be built by molding or three-dimensional printing. The original module 34 can also be provided with a coating 340. Thereafter, the flow further proceeds to step S2.

[0081] In step S2, the openings 347, 348, 349 are machined. The machining of the openings 347, 348, 349 can be performed with a drill. At least a portion of the openings 347, 348, 349 can be etched. Optionally, after machining the openings 347, 348, 349, the original module 34 can be provided with a coating 340. In this case, the openings 347, 348, 349 can also be protected from corrosion. Thereafter, the flow further proceeds to step S3.

[0082] In step S3, the threads 3471, 3481, 3491 of the openings 347, 348 are machined. The machining of the openings 347, 348 can be performed with a thread cutting tool. Optionally, after machining the threads 3471, 3481, 3491 of the openings 347, 348, 349, the original module 34 can be provided with a coating 340. In this case, the openings 347, 348, 349 completed with the threads 3471, 3481, 3491 can also be protected from corrosion. Thereafter, the flow further proceeds to step S4.

[0083] In step S4, the plugs 3473 can be fastened, in particular screwed, into the threads 3471, 3481 of the openings 347, 348 for the coolant channel. Further, a seal 3405 can be inserted into the openings 347 of the respective module 3401, 3402 to provide an inlet or outlet of the coolant channel. Thereafter, the method ends.

[0084] Steps S1 to S4 can be performed for at least two modules 3401, 3402 to build Figures 6 to 8 the transformer-rectifier unit shown in Fig. 1. In this context, steps S1 to S4 can be performed at least partially simultaneously.

[0085] Figure 10 A method for producing a transformer 30 is very schematically shown, as described above with reference to Figures 5 to 8 .

[0086] The method has a step S11 in which at least one of the modules 3401, 3402 is provided. The term “provided” includes that at least one of the modules 3401, 3402 is produced as described above with reference to Figure 9 . Thereafter, the flow further proceeds to step S12.

[0087] In step S12, the openings 347, 348, 349 are machined as Figure 6As shown, at least two modules 3401, 3402 are assembled in the stack with the modules 401 to 405 of the rectifier 40. I.e. the stack of the rectifier 40 is stacked such that the first spring package module 404, the first module 3401, the first soldered semiconductor module 401, the central rectifier module 403, the second soldered semiconductor module 402, the second module 3402 and the second spring package module 405 are positioned adjacent to each other in this order. Herein, the outer form and / or shape of the first and second module 3401, 3402 is at least identical. The first and second module 3401, 3402 are rotated by 180° to each other such that the windings 341 of the first and second module 3401, 3402 face each other and the mounting units 342 of the first and second module 3401, 3402 face each other. The stack is fastened by fastening elements 408 which are inserted and fastened into the third openings 349 of the modules 401 to 405, 3401, 3402. Thereafter, the process further proceeds to step S13.

[0088] In step S13, the contact units 45 for connecting to the positive pole and the contact units 46 for connecting to the negative pole are mounted to the stack built in step S12. This can also be made with screws. Thereafter, the process further proceeds to step S14.

[0089] In step S14, the secondary winding 341 is mounted on the core 33 of the transformer 30. For this, the core 33 is inserted into the recess 344 of the secondary winding 341. Further, at least one primary winding 31 is mounted on the core 33. Thereafter, the process further proceeds to step S15.

[0090] In step S15, at least the secondary winding 341 is molded with a resin, in particular an epoxy resin. Thereafter, the method ends.

[0091] Steps S11 to S14 can be executed at least partially simultaneously. Additionally or alternatively, steps S11 to S14 can be executed at least partially in a changed order.

[0092] Thereby, a low-cost soldering transformer 30 can be built without the need for hard soldering. The soldering transformer 30 has a minimum of single parts and is very stable in construction.

[0093] According to a second embodiment, Figure 2 The modules 34 are further cut in a plane which is approximately orthogonal to the axis of the recess 344. Herein, the cut can be made or present in a plane which is approximately parallel to the front and back face of the module 34. In other words, the cut is made or present in the direction of the middle line M. According to an alternative, the cut can be inclined to the front and back face of the module 34.

[0094] Thus, one module 34 has at least two windings 341. Such windings 241 are positioned approximately parallel to each other. Openings 347, 348 for cooling channels can be individually machined in each winding 341.

[0095] All the above-mentioned embodiments of the device 1, the transformer 30, the rectifier 40 and the above-mentioned method can be used individually or in all possible combinations thereof. The features of the described embodiments and / or modifications thereof can be combined arbitrarily. In particular, the following modifications can be envisaged.

[0096] The dimensions shown in the drawings serve to illustrate the principles of the application and are not limiting. The actual dimensions of the module 34 and its components can be chosen appropriately to meet the above-mentioned functionality.

[0097] The elements shown in the drawings are depicted schematically and can differ in specific embodiments from the forms shown in the drawings as long as the above-mentioned functionality is ensured.

[0098] The number of secondary windings 32, 341 can be chosen as desired. The number can be at least two.

[0099] It is possible that one of the windings 341 does not have a cooling channel.

Claims

1. A welding transformer (30) for a welding tool (10), the welding transformer (30) comprising: a magnetic core (33); at least one primary winding (31) wound around the magnetic core (33) such that the at least one primary winding (31) is connectable with a power supply (25) to supply a primary voltage to the at least one primary winding (31); and at least two modules (3401, 3402), wherein each module (3401, 3402) of the at least two modules (3401, 3402) is a plate-shaped module formed as one piece, the module comprising: at least one secondary winding (32; 341) wound around the magnetic core (33) such that the at least one secondary winding (32; 341) is capable of converting the primary voltage into a secondary voltage (U21, U22) for supplying a welding current (I2) to the welding tool (10); a recess (344) around which the secondary winding (32; 341) is wound and into which the magnetic core (33) is to be inserted; a mounting unit (342) for mounting a rectifier (40) for rectifying the secondary voltage (U21, U22) to the welding transformer (30) to supply a direct current to the welding tool (10) as the welding current (I2); a first gap (345); a second gap (346); and a connector (343), wherein the at least one secondary winding (32; 341) has a first end (3411) and a second end (3412), wherein the connector (343) connects the first end (3411) and the mounting unit (342), wherein the second end (3412) is a free end of the secondary winding (32; 341) and is spaced apart from the mounting unit (342) by the first gap (345), wherein the second gap (346) separates the connector (343) and the second end (3412), and wherein the second gap (346) separates the first end (3411) and the second end (3412) of the secondary winding (341). Each module (3401, 3402) of the at least two modules (3401, 3402) comprises a coolant channel.

2. The welding transformer (30) of claim 1, wherein, The coolant channel comprises an opening (347) for an inlet and / or an outlet of the coolant, and wherein the opening (347) is positioned between the at least one secondary winding (32; 341) and the mounting unit (342).

3. The welding transformer (30) of claim 2, wherein, Each module (3401; 3402) of the at least two modules (3401; 3402) comprises at least one blind hole (347) and at least one through hole (348) which cross each other to form the coolant channel.

4. The welding transformer (30) according to claim 2 or 3, wherein ​ 5. The welding transformer (30) of claim 4, wherein, At least one of the at least one blind hole (347) and the at least one through hole (348) comprises a thread (3471; 3481) to seal the coolant channel to the outside with a threaded plug (3473).

6. The welding transformer (30) according to any one of claims 1 to 3, wherein The form of the secondary winding (32; 341) of one module (3401; 3402) differs from the form of the mounting unit (342) of the module (3401; 3402).

7. The welding transformer (30) according to any one of claims 1 to 3, wherein The secondary winding (32; 341) of one of the modules (3401; 3402) is connected with the mounting unit (342) of the module (3401; 3402) via the connector (343), which is positioned offset from the center line (M) of the module (3401; 3402).

8. The welding transformer (30) of claim 7, wherein, The welding transformer (30) comprises a first module (3401) and a second module (3402) having the same outer form and / or shape, and wherein the first module (3401) and the second module (3402) are positioned spaced apart from each other and side by side, such that the connector of the first module (3401) is positioned on the other side of the center line (M) of the first module (3401) compared to the connectors (343) of the second module (3402).

9. The welding transformer (30) according to any one of claims 1 to 3, wherein, The at least two modules (3401, 3402) are made of copper or aluminum.

10. The welding transformer (30) according to any one of claims 1 to 3, wherein, Each of the at least two modules (3401, 3402) is coated with a coating (340) protecting the module (3401; 3402) from corrosion.

11. A welding tool (10) for producing an article (4), the welding tool (10) comprising a welding transformer (30) according to any one of claims 1 to 10 and a control unit (20) configured to adjust a welding current (I2) for forming the article by joining at least two parts of one component (5) and / or at least two components (5; 6) by at least one welding joint (7).

12. The soldering tool (10) according to claim 11, wherein The welding tool (10) further comprises means (50) for moving the welding tool (10) along the at least two parts and / or the at least two components (5, 6) according to a predetermined movement profile, and wherein the article (4) is a vehicle body.

13. A method for producing a module (3401; 3402) for a welding transformer (30), the method comprising the steps of: forming (S1) a plate-shaped module (34) as one component, such that the module (34) comprises a secondary winding (341), a recess (344), a mounting unit (342) for mounting a rectifier (40) to the welding transformer (30), a first gap (345), a second gap (346), and a connector (343), the secondary winding (32; 341) is wound around the recess (344), and a magnetic core (33) of the welding transformer (30) is to be inserted in the recess (344), wherein the secondary winding (32; 341) has a first end (3411) and a second end (3412), wherein the connector (343) connects the first end (3411) and the mounting unit (342), wherein the second end (3412) is a free end of the secondary winding (32; 341) and is spaced apart from the mounting unit (342) by the first gap (345), wherein the second gap (346) separates the connector (343) and the second end (3412), and wherein the second gap (346) separates the first end (3411) and the second end (3412) of the secondary winding (341); and machining (S2) at least one blind hole (347) and at least one through hole (348) into the module (34), such that the at least one blind hole (347) and the at least one through hole (348) cross each other to form a coolant channel in the module (34).

14. A method for producing a welding transformer (30), the method comprising the steps of: positioning (S12) a first module (3401) laterally inverted with respect to a second module (3402), wherein the first module (3401) and the second module (3402) have at least the same outer form, wherein each module (34) is a plate-shaped module formed as one piece, the module comprising a secondary winding (341), a recess (344), a mounting unit (342) for mounting a rectifier (40) to the welding transformer (30), a first gap (345), a second gap (346) and a connector (343), the secondary winding (32; 341) being wound around the recess (344) and a magnetic core (33) of the welding transformer (30) is to be inserted in the recess (344), wherein the secondary winding (32; 341) has a first end (3411) and a second end (3412), wherein the connector (343) connects the first end (3411) and the mounting unit (342), wherein the second end (3412) is a free end of the secondary winding (32; 341) and is spaced apart from the mounting unit (342) by the first gap (345), wherein the second gap (346) separates the connector (343) and the second end (3412), wherein the second gap (346) separates the first end (3411) and the second end (3412) of the secondary winding (341), and wherein the first module (3401) and the second module (3402) are positioned such that the secondary windings (341) of the first module (3401) and the second module (3402) are positioned facing each other; positioning and fastening (S13) at least two semiconductor modules (401, 402) between the mounting units (342) of the first module (3401) and the second module (3402) to build a stack, wherein the at least two semiconductor modules (401, 402) are positioned in the stack on both sides of a central module (403) of the rectifier (40).

15. The method of claim 14, further comprising the step of: mounting (S14, S15) the magnetic core (33) of the transformer (30) into the recess (344) of the secondary winding (341) of the at least two semiconductor modules (401, 402).

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