PROCESS ARRANGEMENT FOR A METAL SHIELDED GAS WELDING OR BRAZING PROCESS

Description

[0001] The invention relates to a process arrangement for a metal arc welding or soldering process according to the preamble of claim 1.

[0002] A key aspect of the invention is that the torch can be designed without a shielding gas nozzle. In this case, the shielding gas is supplied to the torch passage solely via the shielding gas channel of the auxiliary tool. This results in advantages regarding torch design, torch cleaning, and accessibility. A prior art process arrangement can be found, for example, in US Pat. No. 2,590,084.

[0003] Using such a process arrangement, a weld or solder joint (e.g., a welding or soldering point) is created to connect a component assembly. Such a weld or soldering point can, for example, secure a seamed flange connection between sheet steel components. The two sheet steel components can, for example, form a vehicle door that can be installed as an add-on part to a vehicle body.

[0004] A generic process arrangement is known from DE 10 2019 211 860 A1. This comprises an auxiliary tool that protects the area adjacent to the welding or soldering point from welding-related smoke traces during the gas metal arc welding process. The auxiliary tool has a torch aperture through which a torch with its electrode can be brought into operative contact with the component assembly, specifically to form the welding or soldering point. The auxiliary tool has a shielding gas connection that can be connected to a shielding gas source. Shielding gas can flow into the torch aperture via the shielding gas connection to shield the molten metal in the welding or soldering point.

[0005] In the above prior art, the shielding gas flow path in the auxiliary tool is implemented with a radially outer annular chamber. This merges radially inward into a reduced-cross-section, annular nozzle chamber. The nozzle chamber is in flow connection with the torch passage via an annular gap on the bottom. Both the radially outer annular chamber, the nozzle chamber, and the annular gap are open on the underside of the auxiliary tool, so that the shielding gas flowing through is in direct contact with the component composite surface. A shielding gas annular flow is generated in the radially outer annular chamber, which, as it continues through the torch passage, forms a vortex flow around a central axis of the torch passage. Overall, this results in comparatively long shielding gas flow paths in the auxiliary tool, so that the auxiliary tool requires a correspondingly high installation space.Therefore, the use of the auxiliary tool is not possible in an environment with limited installation space, such as the above-mentioned seam flange connection.

[0006] DE 10 2016 225 831 A1 discloses a clamping element for a clamping device for welding workpieces. EP 1 862 248 A1 discloses a device for preventing contamination on a component surface adjacent to a weld seam by weld spatter generated during MIG / MAG welding.

[0007] The object is solved by the features of claim 1. Preferred developments of the invention are disclosed in the subclaims.

[0008] The invention is based on an auxiliary tool that can be used in a metal arc welding or soldering process. The auxiliary tool has a torch passage through which a torch with its electrode can be brought into operative contact with a component to be joined, specifically to form a weld or solder joint, for example a welding or soldering point. The auxiliary tool has a shielding gas connection that can be connected to an external shielding gas source. The shielding gas can flow into the torch passage via the shielding gas connection to shield the molten metal in the welding or soldering point. The torch can be designed without a shielding gas nozzle, so that the shielding gas is supplied to the torch passage solely via a shielding gas channel of the auxiliary tool.

[0009] It should be emphasized that the invention is applicable to all suitable welding or brazing processes, for example also to linear MAG / MIG welding or brazing.

[0010] According to the characterizing part of claim 1, the shielding gas flow path guided through the auxiliary tool is designed to be more compact compared to the prior art, so that the auxiliary tool has significantly smaller component dimensions compared to the prior art. In this way, the auxiliary tool according to the invention can also be used in a space-limited environment, such as in a seamed flange connection described later. With a view to a space-reduced design, the auxiliary tool has at least one shielding gas channel that connects the shielding gas connection directly to the torch passage, i.e., without the interposition of flow chambers.

[0011] In contrast to the prior art, the shielding gas channel according to the invention therefore runs at least partially inside the auxiliary tool. The flow cross-section of the shielding gas channel is therefore completely delimited by the auxiliary tool material, so that the shielding gas flowing in the shielding channel has no contact with the component assembly. In contrast to the prior art, the shielding channel according to the invention extends with a straight channel axis from the shielding gas connection directly into the torch passage, so that the shielding gas can flow linearly towards the torch passage, without annular flow in an otherwise interposed annular flow chamber. In this way, shorter flow paths result in the auxiliary tool compared to the prior art, which means that the auxiliary tool can be designed with a smaller installation space.

[0012] The torch is a separate component from the auxiliary tool. During the welding or brazing process, the torch extends into the torch passage from the side of the auxiliary tool facing away from the component assembly. This occurs without contact, i.e., forming an annular gap between the torch or torch electrode and the inner wall of the tool. During the welding or brazing process, the shielding gas in the torch passage can thus flow outward through the annular gap to the outside of the tool.

[0013] In one technical implementation, the torch passage can be rotationally symmetrical about a tool center axis. The torch passage can be divided along the tool center axis into a central chamber facing the component assembly and a funnel-shaped inlet opening facing away from the component assembly. The welding or soldering point can be created in the central chamber of the torch passage by forming an arc between the electrode and the component assembly. Preferably, the chamber cross-section of the central chamber can expand towards the component assembly. The central chamber and the funnel-shaped inlet opening can be in flow connection with one another at a transition with a reduced cross-section.

[0014] As mentioned above, the torch can be designed without a shielding gas nozzle. In this case, the shielding gas is supplied to the torch passage solely via the shielding gas channel of the auxiliary tool. To avoid depression of the molten metal or excessive welding or soldering point elevation during the welding or brazing process, it is preferable for the shielding gas flow to impinge on the molten metal at an accelerated rate. Against this background, it is advantageous if the flow cross-section of the shielding gas channel tapers towards its outlet opening. The main effect of the accelerated shielding gas flow is to create a more stable shielding plane (surface) of shielding gas above the component surface, which can reliably prevent smoke deposits.

[0015] The opening of the shielding gas channel is formed in an inner wall of the tool that limits the torch passage.

[0016] In a further development of the invention, at least two shielding gas channels can be formed in the auxiliary tool. In a first variant, shielding gas can be supplied to the torch passage via each of the two shielding gas channels. Alternatively, gas can be supplied via only one shielding gas channel, while the other shielding gas channel is used for shielding gas removal.

[0017] Preferably, the orifices of the two shielding gas channels can open into the torch passage on diametrically opposite sides with respect to the tool center axis.

[0018] According to the invention, the size of the auxiliary tool can be adapted for use in a special, space-limited environment, which is described below: accordingly, the component assembly can be constructed from two sheet steel parts that are connected to one another at the edges via a folded flange connection. The folded flange connection can protrude from a sheet steel part structure over a flange width. Furthermore, the folded flange connection can extend at least partially along the longitudinal direction of the sheet steel part structure (e.g., door structure). The flange of a first sheet steel part can be extended beyond the flange of the second sheet steel part by a folded web in the flange width direction. The folded web is folded over 180° at a folded axis, resulting in a three-layer structure consisting of the folded web and the outer flange of the first sheet steel part with the middle flange of the second sheet steel part clamped between them.Between the folded web and the center flange, a sheet metal step is formed, the step height of which corresponds to the sheet thickness of the first steel sheet part. In this case, the welding or soldering point can be placed directly at the sheet metal step to connect the folded web to the center flange.

[0019] A key aspect of the invention is that the auxiliary tool is specifically adaptable to the seamed flange connection indicated above. Against this background, the auxiliary tool can be approximately cuboid-shaped, with a component length extending in the longitudinal direction of the flange and a component width extending in the direction of the flange width. The component width of the auxiliary tool is preferably smaller than the flange width of the seamed flange connection.

[0020] With a view to a space-efficient design of the auxiliary tool, it is preferred if the at least one shielding gas channel extends in the longitudinal direction of the flange. If necessary, the shielding gas channel may not be aligned directly in longitudinal alignment with the longitudinal direction of the flange, but rather be offset from it by a slight angle. In this case, the shielding gas channel is formed in an inclined position in the auxiliary tool, in which the shielding channel axis forms a slight angle with the longitudinal direction of the flange. Alternatively and / or additionally, the shielding gas channel may be inclined by a tilt angle in the vertical direction of the auxiliary tool, specifically downwards in the direction of the torch passage.

[0021] The outlet opening of the shielding gas channel can preferably be formed in the immediate vicinity of the component assembly in the inner wall of the auxiliary tool. If two shielding gas channels are provided in the auxiliary tool, the following applies: the shielding gas coming from one outlet opening can flow directly onto the seam web. In contrast, the shielding gas coming from the second outlet opening can flow directly onto the flange of the second sheet steel part (exposed by the seam web). In this case, it is preferred if the second outlet opening is positioned at a height offset below the first outlet opening (taking into account the sheet metal gradation).

[0022] Embodiments of the invention are described below with reference to the attached figures.

[0023] They show: Fig. 1 shows a finished seam flange connection with a weld or soldering point in place; Figs. 2 to 4 show different views of an auxiliary tool placed on the seam flange connection for carrying out a metal arc welding or soldering process; Figs. 5 to 8 show further embodiments of the auxiliary tool.

[0024] In Figure 11 shows a finished component assembly 1 which is constructed from two sheet steel parts 3, 5 that form a sheet steel part structure 9 (for example a door structure). The two sheet steel parts 3, 5 are connected to one another at the edges via a folded flange connection 7. This projects from the sheet steel part structure 9 over a flange width b. In addition, the folded flange connection 7 extends at least partially along the sheet steel part structure 9 in a flange longitudinal direction x. The folded flange connection 7 is realized as follows: A flange 11 of the first sheet steel part 3 is extended with a folded web 13 in the flange width direction y beyond the flange 15 of the second sheet steel part 5. The folded web 13 is folded over by 180° at a folded axis F. In this way, a three-layer structure is obtained from the folded web 13 and the outer flange 11 of the first steel sheet part 3 with the middle flange 15 of the second steel sheet part 5 clamped between them.Between the folded web 13 and the central flange 15, a sheet metal step 17 is formed, the step height of which corresponds to the sheet thickness of the first steel sheet part 3. Directly on the sheet metal step 17, a welding or soldering point 19 is placed, which connects the folded web 13 to the flange 15 of the second steel sheet part 5. In the . Figure 1 Therefore, a lap joint is shown in which the upper seam web 13 merges step-like into the flange 15 of the second steel sheet part 5.

[0025] The welding or soldering point 19 is set using a process arrangement, which is subsequently described using the Figures 2 to 4is described. Accordingly, by means of the process arrangement, a metal-shielded gas welding or soldering process is carried out with the aid of a torch 21. During the welding or soldering process, the torch, with its electrode 23, is in operative connection with the component assembly 1, so that the welding or soldering point 19 can be created by forming an arc 25 between the electrode 23 and the component assembly 1. The metal-shielded gas welding or soldering process is preferably part of a fully automated process chain for producing the component assembly 1.

[0026] The process arrangement also has an auxiliary tool 27, which is placed on the component assembly 1 during the welding or soldering process. The auxiliary tool 27 protects the area adjacent to the welding or soldering point 19 from welding-related traces of smoke. According to the Figure 2 The auxiliary tool 27 is part of a pivoting clamping jaw of a clamping unit (not shown). Figure 2the pivoting clamping jaw together with the auxiliary tool 27 is clamped against a stationary clamping jaw 31 of the clamping unit with the component assembly 1 interposed.

[0027] The geometry of the auxiliary tool 27 is specifically designed for the use of the metal arc welding or soldering process to create the welding or soldering point 19 on the space-restricted seam flange connection 7. Accordingly, the auxiliary tool 27 is approximately cuboid-shaped with a component length Δx ( Figure 4 ) and a component width Δy ( Figure 4 ). The component width Δy of the auxiliary tool 27 is smaller than the flange width b of the seam flange connection 7, so that the auxiliary tool 27 can be reliably supported on the seam flange connection 7.

[0028] According to the Figures 2 to 4The auxiliary tool 27 has a burner passage 33, via which the burner 21 with its electrode 23 can be brought into operative connection with the component assembly 1. The burner passage 33 is in the Figure 2 rotationally symmetrical about a tool central axis W. Along this central axis W, the torch passage 33 is divided into a welding chamber 35 facing the component assembly 1, in which the welding or soldering point 19 can be produced by forming the arc 25, and into a funnel-shaped insertion opening 37 facing away from the component assembly 1. Figure 2 The cross-section of the welding chamber 35 expands toward the lap joint. The welding chamber 35 and the insertion opening 37 are connected to each other by a reduced-cross-section transition 39.

[0029] As from the Figure 3 or 4As can be seen, the auxiliary tool 27 has two shielding gas channels 41. Each of the shielding gas channels 41 connects a shielding gas connection 43 directly to the torch passage 33. The two shielding gas channels 41 are in flow connection with the torch passage 33 via orifices 45. According to the Figure 4 the two orifices 45 are each formed in an inner tool wall 47 which delimits the burner passage 33.

[0030] According to the Figures 3 and 4The outlet openings 45 of the two shielding gas channels 41 are formed on diametrically opposite sides in the inner wall 47 of the auxiliary tool with respect to the central axis W. The two outlet openings 45 are positioned in such a way that a swirling flow around the auxiliary tool central axis W is produced in the torch passage 33. For this purpose, each of the two shielding gas channels 41 is formed in an inclined position in the auxiliary tool 27, in which the respective shielding channel axis A forms an angle α ( Figure 4 ) spans.

[0031] In order to be able to reliably reproduce this step-like joining geometry of the lap joint, a corresponding step 30 ( Figure 2 ) trained.

[0032] As from the Figure 3As can be seen further, the flow cross-section of the respective shielding gas channel 41 tapers in the direction of its mouth opening 45. The two mouth openings 45 are each formed in the immediate vicinity of the component assembly 1 in the inner wall 47 of the auxiliary tool.

[0033] According to the Figure 3 The shielding gas coming from the first orifice 45 flows directly onto the seam web 13, while the shielding gas coming from the second orifice 45 flows onto the flange 15 of the second sheet steel part 5. Taking into account the step height of the sheet step 17, the second orifice 45 is offset by a height offset Δz ( Figure 2 ) positioned below the first mouth opening 45.

[0034] During the welding or soldering process, the torch 21 protrudes from the auxiliary tool side facing away from the component assembly 1 into the funnel-shaped insertion opening 37 of the torch passage 33, without contact, so that an annular gap is created between the torch 21 or the torch electrode 23 and the tool inner wall 27. The shielding gas flowing into the torch passage 33 via the two shielding gas channels 41 is discharged to the outside of the tool via the annular gap.

[0035] In the Figures 5 and 6 A second embodiment of the invention is shown. The auxiliary tool 27 is essentially identical in construction to the auxiliary tool 27 according to the first embodiment, so that reference is made to the previous description. In contrast to the first embodiment, in the Figures 5 and 6 A gas supply into the burner passage 33 is provided via one of the two protective channels 41, while a protective gas discharge is provided via the other protective gas channel 41.

[0036] In the Figure 7a the two shielding gas channels 41 of the auxiliary tool 27 are not aligned in the flange longitudinal direction x, but rather transversely thereto, i.e. in the flange width direction y. The two outlet openings 45 of the shielding gas channels 41 are positioned so that the shielding gas flowing out is directed either directly onto the seam web 13 of the component connection ( Figure 7c ) or is directed directly onto the flange 15 of the second sheet steel part 5 ( Figure 7b ) in order to achieve the best possible vortex flow.

[0037] In the Figure 8 A further embodiment is shown in which the auxiliary tool 27 has a total of four shielding gas channels 41, each of which opens into the torch passage 33 at separate openings 45. This results in a more space-intensive design of the auxiliary tool 27 compared to the first embodiment.

[0038] The metal arc welding or soldering process is preferably part of a fully automated process chain for the production of the component assembly 1. LIST OF REFERENCE SYMBOLS:

[0039] 1Component assembly 3, 5Steel sheet parts 7Seam flange connection 9Steel sheet part structure 11Flange of the first steel sheet part 3 13Seam web 15Flange of the second steel sheet part 5 17Sheet step 19Welding or soldering point 21Torch 23Electrode 25Light base 27Auxiliary tool 30Step 31Stationary clamping jaw 33Torch passage 35Welding chamber 37Funnel-shaped inlet opening 39Transition 41Shielding gas channels 43Shielding gas connection 45Orifice openings 47Auxiliary tool inner wall FFeam axis WTool center axis AShielding gas channel axis bFlange width ΔxComponent length ΔyComponent width

Claims

1. Process arrangement for a gas-shielded metal arc welding or soldering process, by means of which a welding or soldering point (19) can be set for joining a component assembly (1), the process arrangement having an auxiliary tool (27) which, during the welding or soldering process, protects the area adjacent to the welding or soldering point (19) from traces of smoke, wherein the auxiliary tool (27) has a burner passage (33) via which a burner (21) with its electrode (23) can be brought into operative connection with the component assembly (1), specifically to form the welding or soldering point (19), and wherein the auxiliary tool (27) has a shielding gas connection (43) which can be connected to a shielding gas source and via which shielding gas can flow into the burner passage (33) in order to shield the molten metal in the welding or soldering point (19), wherein, with a view to a configuration with reduced installation space, the auxiliary tool (27) is designed with at least one shielding gas channel (41) which connects the shielding gas connection (43) directly, that is, without the interposition of flow chambers, to the burner passage (33), and wherein the mouth opening (45) of the shielding gas channel (41) is formed in an inner tool wall (47) delimiting the burner passage (33), characterized in that the mouth opening (45) is positioned in the auxiliary tool inner wall (47) such that a turbulent flow is formed in the burner passage (33) around the auxiliary tool central axis (W).

2. Process arrangement according to claim 1, characterized in that the process arrangement has a burner and in the burner (21) is designed without a shielding gas nozzle, so that the shielding gas supply into the burner passage (33) takes place solely via a shielding gas channel (41) of the auxiliary tool (27).

3. Process arrangement according to claim 1 or 2, characterized in that the shielding gas channel (41) extends at least partially inside the auxiliary tool (27), so that in particular the flow cross-section of the shielding gas channel (41) is completely delimited by auxiliary tool material and / or the shielding gas channel (41) has no direct flow connection to the component assembly (1) or is closed with respect to the component assembly (1), and / or in that the shielding gas flowing in the shielding gas channel (41) has no contact with the component assembly (1), and / or in that the process arrangement has a burner and in that in the welding or soldering process the burner (21) protrudes into the burner passage (33) from the auxiliary tool side facing away from the component assembly (1), specifically forming an annular gap between the burner (21) or the burner electrode (23) and the inner tool wall (47), and in that, in particular, the shielding gas in the burner passage flows out to the outside of the tool via the annular gap.

4. Process arrangement according to any one of the preceding claims, characterized in that the burner passage (33) is designed to be rotationally symmetrical about a tool central axis (W), and / or in that in particular the burner passage (33), in particular along the central axis (W), is divided into a central chamber (35) facing the component assembly (1), in which chamber the welding or soldering point (19) can be produced by forming an arc (25) between the electrode (23) and the component assembly (1), and into an inlet opening (37) facing away from the component assembly (1), in particular a funnel-shaped inlet opening, and / or in that the chamber cross-section of the central chamber (35) widens in the direction of the component assembly (1), and / or in that the central chamber (35) and the inlet opening (37) are connected to one another at a transition (39) with a reduced cross-section.

5. Process arrangement according to any one of the preceding claims, characterized in that the flow cross-section of the shielding gas channel (41) tapers in the direction of its mouth opening (45), and / or in that the shielding gas channel (41) extends rectilinearly in the auxiliary tool (27), so that the shielding gas flows linearly in the direction of the burner passage (33).