WELDING METHOD AND WELDING APPARATUS FOR WELDING CONDUCTOR ENDS

Abstract

To improve quality and reduce reject in the large-scale production of components of an electrical machine provided with coil windings, a welding method is provided for welding conductor ends organized into groups of conductor ends of a component for an electrical machine. The method includes detecting a relative position of a first conductor end and a second conductor end of a group of conductor ends, and controlling a welding energy input to the conductor ends to be welded depending on the detected relative position. A welding apparatus for performing the welding method is also provided.

Claims

1-13. (canceled)

14. A welding method for welding conductor ends organized into groups of conductor ends of a component for an electrical machine, comprising: a) detecting a relative position of a first conductor end and a second conductor end of a group of conductor ends; and b) controlling a welding energy input to the conductor ends to be welded depending on the detected relative position.

15. The welding method according to claim 14, further including c) detecting at least one size parameter of a molten pool formed during welding, and d) controlling the welding energy input depending on the detected size parameter of the molten pool.

16. The welding method according to claim 14, further including e) detecting at least one size parameter of a weld bead solidified after welding; and f) controlling the welding energy input during a subsequent welding of a further group of conductor ends depending on the detected size parameter of the solidified weld bead.

17. The welding method according to claim 16, wherein step e) comprises at least one of e1) being performed on a first group of conductor ends, while step b) is already being performed on a second group of conductor ends; e2) being performed to characterize a result of the welding; or e3) comparing the at least one size parameter with a predetermined parameter value or parameter value range.

18. The welding method according to claim 14, wherein at least one of steps a), c) and/or e) comprises at least one or more of the following steps: a1) position measuring using optical measuring methods; a2) position measuring by means of time-of-flight measurement of reflected radiation; a3) performing an optical coherence tomography; a4) alternately directing a measuring radiation to different groups of conductor ends; a5) measuring distances or stretches in at least two dimensions at the group of conductor ends; a6) measuring a distance or a stretch in a direction of an extension of conductor sections comprising ends of the conductors; a7) determining a distance between the conductor ends; a8) measuring a height offset between the conductor ends; a9) determining a cross-sectional area of the end region of a group of conductor ends; a10) determining a volume of an end region of the group of conductor ends; a11) measuring at least one of a thickness, a width or a height of the end region at the group of conductor ends; a12) detecting a change in at least one dimension of the end region of the group of conductor ends.

19. The welding method according to claim 14, wherein at least one of step b), step d) or step f) comprises at least one or more of the following steps: b1) directing a welding beam onto the group of conductor ends; b2) starting the welding energy input to the group of conductor ends; b3) stopping the welding energy input to the group of conductor ends; b4) increasing or decreasing the welding energy input to the group of conductor ends; or b5) changing a beam cross-section of a welding beam on the group of conductor ends.

20. A welding apparatus for welding conductor ends organized into groups of conductor ends of a component for an electrical machine, comprising: a welding means for inputting welding energy to a group of conductor ends; a measuring device for detecting a relative position of a first conductor end and a second conductor end of the group of conductor ends, and a control device which is configured to control a welding energy input to the conductor ends to be welded as a function of the detected relative position.

21. The welding apparatus according to claim 20, wherein the measuring device is configured to detect at least one size parameter of a molten pool produced during welding, and wherein the control device is configured to control the welding energy input as a function of the detected size parameter of the molten pool.

22. The welding apparatus according to claim 20, wherein the measuring device is configured to detect at least one size parameter of a weld bead solidified after welding, and wherein the control device is configured to control a welding energy input during subsequent welding of a further group of conductor ends as a function of the detected size parameter of the solidified weld bead.

23. The welding apparatus according to claim 22, wherein the measuring device at least one of: has at least one or more deflection mirrors by means of which measuring radiation can be selectively guided to different groups of conductor ends, and is configured to measure the size parameter of the weld bead solidified after welding at a first group of conductor ends and at the same time to detect at least one of a relative position of the conductor ends or the size parameter of the molten pool already at a second group of conductor ends; is configured to evaluate a result of the welding; or comprises a comparison device for comparing the at least one size parameter with a predetermined parameter value or parameter value range.

24. The welding apparatus according to claim 20, wherein the measuring device is at least one device selected from a group of measuring devices comprising: a measuring device for position measurement by means of optical measuring methods; a measuring device for position measurement by means of time-of-flight measurement of reflected radiation; a measuring device for performing optical coherence tomography; a measuring device for alternately directing a measuring radiation to different groups of conductor ends; a measuring device for measuring distances or stretches in at least two dimensions at the group of conductor ends; a measuring device for measuring a distance or a stretch in a direction of the extension of the conductor sections comprising the conductor ends; a measuring device for measuring a distance between the conductor ends; a measuring device for measuring a height offset between the conductor ends; a measuring device for determining a cross-sectional area of the end region of the group of conductor ends; a measuring device for determining a volume of the end region of the group of conductor ends; a measuring device for measuring a thickness, a width and/or a height of the end region at the group of conductor ends; or a measuring device for detecting a change in at least one dimension of the end region of the group of conductor ends.

25. The welding apparatus according to claim 20, wherein the control device is configured to control the welding apparatus to at least one of: b1) direct a welding beam onto the group of conductor ends; b2) start the welding energy input to the group of conductor ends; b3) stop the welding energy input to the group of conductor ends; b4) increase or decrease the welding energy input to the group of conductor ends; or b5) change a beam cross section of a welding beam on the group of conductor ends.

26. A computer program product comprising machine-readable control instructions which, when loaded into a controller of a welding apparatus for welding conductor ends organized into groups of conductor ends of a component for an electrical machine, the welding apparatus comprising: a welding means for inputting welding energy to a group of conductor ends; a measuring device for detecting a relative position of a first conductor end and a second conductor end of the group of conductor ends, and a control device which is configured to control a welding energy input to the conductor ends to be welded as a function of the detected relative position, cause the welding apparatus to perform the welding method according to claim 14.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0193] Examples of embodiments of the invention are explained in more detail below with reference to the accompanying drawings wherein it is shown by

[0194] FIG. 1 is a schematic block diagram of a welding arrangement with a component having pairs of conductor ends protruding from the component—as an example of a group of conductor ends—and an embodiment of a welding apparatus for welding the pairs of conductor ends;

[0195] FIGS. 2a to 2e are each a top view of a pair of conductor ends to be welded, with process zone conditions at different times of a welding method inclusive dimension lines;

[0196] FIG. 3 is a perspective view of another pair of conductor ends with different relative positions of the conductor ends before welding, corresponding to the state of FIG. 2a;

[0197] FIGS. 4a to 4d, 5a to 5d and 6a to 6d are each an isometric view of the pair of conductor ends to be welded corresponding to the states of FIGS. 2a to 2d, namely in perspective view, in side view and in plan view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0198] FIG. 1 shows an embodiment of a welding arrangement 10 comprising a component 12 to be processed and a welding apparatus 14. Conductor ends 16, 16a, 16b protrude from the component 12 and are organized into groups of conductor ends 18, in particular pairs of conductor ends 20, of conductor ends 16a, 16b to be connected to each other. The component 12 is a component of an electric machine to be mass-produced, such as an electric motor to be used as a traction motor for electric or hybrid vehicles. Coil windings of the component 12 are produced by connecting conductor ends 16.

[0199] For example, the component 12 is a stator 22 of the electric motor. The conductor ends 16 are, for example, the ends designated as pins 1 of hairpins, i.e., of approximately U-shaped pieces of wire, in particular of rectangular wire, which are inserted into grooves of a housing (laminated core) 24 of the stator 22. By connecting the free ends of the hairpins, the coil windings extending through the stator 22 in a wave-like manner can be formed. For more details on the structure of the stator 22, the hairpins and the manufacturing method for the stator 22, reference is made to the literature [1] to [4] mentioned at the beginning. As can be seen from this literature, before the coil windings are welded together, a large number of conductor ends 16 protrude from one end of the housing 24, mostly grouped into pairs of conductor ends 20, 20a-20e. A first conductor 16a and a second conductor 16b of a pair of conductor ends 20, 20a-20e are usually to be welded together so as to connect one hairpin to another hairpin. However, it may also be the case that three or more conductor ends 16 are to be connected to each other, which is then also to be carried out by welding as described in more detail below. The welding will be explained below with reference to the example of the group of conductor ends 18 being formed as a pair of conductor ends 20.

[0200] A clamping device 25 of the type explained in more detail in [4] can be provided on the component 12, which clamps the conductor ends 16a, 16b of each pair of conductor ends 20 to be welded together. For reasons of illustration, five pairs of conductor ends 20a-20e, which are welded in succession by the welding apparatus 14, are schematically and roughly depicted in FIG. 1. In practice, a significantly larger number (e.g., 150 to 300 or even more) of pairs of conductor ends 20 are to be welded per component 12. In the embodiment of FIG. 1, the first and second pairs of conductor ends 20a, 20b have already been completely welded, which is indicated by a welding seam 6 with a weld bead 27, while the third pair of conductor ends 20c is currently in the welding method, which is indicated by a molten pool 5. The fourth and fifth pairs of conductor ends 20d, 20e would then be welded thereafter.

[0201] Accordingly, the welding apparatus 14 is designed for welding conductor ends 16, 16a, 16b of a component 12 for an electrical machine, which conductor ends are organized into groups of conductor ends 18, 20. The welding apparatus 14 has a welding means 26, a measuring device 28 and a control device 30.

[0202] The welding apparatus 26 is configured to apply welding energy to a group of conductor ends 18. In particular, the welding apparatus 26 may be any beam welding apparatus capable of directing a welding beam 33 sequentially onto the groups of conductor ends 18, 20, 20a-20e. Alternatively, the welding apparatus 26 may comprise a TIG or plasma welder, wherein the conductor ends 20, 20a-20e are successively moved into the welding zone. In the preferred embodiment shown in FIG. 1, the welding apparatus 26 has a laser 32 for generating a laser beam 2 as a welding beam 33 for laser welding and laser optics 34 for deflecting and focusing the laser beam 2. In particular, the laser optics 34 comprises one or more galvanometrically driven deflection mirrors 36 and an optical element 38 for focusing the laser beam 2 and for adjusting the beam cross-section of the laser beam 2. The laser optics 34 may also include apertures (not shown) for blanking out all or an adjustable amount of the laser beam 2. Thus, the laser optics 34 is an example of a device for directing a welding beam 33 onto the group of conductor ends 18 and of a device for starting, stopping, increasing and decreasing the welding energy input to the group of conductor ends 18. At least some of these functions may, of course, be performed by other suitable devices, such as on the laser 32 itself or on or in the beam path between the laser 32 and the laser optics 34.

[0203] The measuring device 28 is designed at least for detecting a relative position of a first conductor end 16a and a second conductor end 16b of the respective group of conductor ends 18, 20, 20a-20e. The measuring device 28 can be designed differently for this purpose as long as it can detect the relative positions between the conductor ends 16a, 16b and transmit a measurement signal indicating the relative position to the control device 30. This is preferably effected by optical measuring methods, such as image capture or optical length measurements, and various measuring devices are available on the market for this purpose. In particular, the measuring device 28 is designed to measure a plurality of dimensions of the end region of the group of conductor ends 18, 20, 20a- 20e. In the preferred embodiment shown in FIG. 1, the measuring device 28 operates via time-of-flight measurement of reflected measuring radiation 40 and more particularly by means of optical coherence tomography (OCT). For this purpose, the measuring device 28 has an OCT device 40 with deflection device (scanner) 42. As can be seen e.g., from literature

[0204] [5] “Optical coherence tomography,” Wikipedia entry, wikipedia.org, retrieved 2020 Mar. 26,

[0205] such OCT devices 40 for performing optical coherence tomography are available on the market for completely different purposes. They are currently used in medicine, particularly for detecting the fundus of the eye in ophthalmology. The deflection device 42 can be used to scan a measuring beam 44 of the OCT device 40 over the respective group of conductor ends 18, 20, 20a-20e to detect the position of the contours of the individual conductor ends 16a, 16b or even the contours, the dimensions and the volume of the molten pool 5 or the weld bead 27 or the welding seam 6.

[0206] The control device 30 is designed to control a welding energy input to the conductor ends 16a, 16b to be welded depending on the measurement signal of the measuring device 28. In particular, the welding energy input can thus be controlled depending on the detected relative position of the conductor ends 16a, 16b. The control device 30 has, for example, a controller comprising a computing unit and a memory in which control instructions are stored as software. The control instructions cause the welding apparatus 14 to perform the welding method explained in more detail below.

[0207] The measuring device 28 and the measuring method carried out with it are based on optical coherence tomography, OCT for short: In a preferred embodiment of the measuring device 28, a measuring beam 44 with a wavelength of approx. 840 nm is emitted. The height information of the area to be measured at the group of conductor ends 18 in the z-direction is determined by calculating the propagation time of the reflected signal.

[0208] In one possible embodiment of the welding method, in contrast to the literature cited in [1] to [4], no joint cutting of the conductor ends 16 takes place after clamping and before welding. In particular, uncut hairpins—pins 1—are present as conductor ends 16, 16a, 16b, as shown in FIGS. 2a, 4a, 5a, 6a and 3, which show pairs of conductor ends 20, 20c, 20d before the welding method. FIG. 2a and FIGS. 2b to 2e also show dimension lines M1-M4 for performing the OCT measurements according to a preferred measurement strategy during the different steps or phases of the welding method.

[0209] The measurement strategy is implemented as a double cross (see the intersecting dimension lines M1 to M4) to characterize the positions of the uncut hairpins before welding in the x-y-z direction. Thus, the size of a gap 46 between the conductor ends 16a, 16b, a height offset HV between the conductor ends 16a, 16b, a radial offset RV (with respect to the radial direction of the component 12 having a central axis), and a tangential offset TV between the conductor ends 16a, 16b can be detected. For example, FIG. 3 shows another pair of conductor ends 20e in which the conductor ends 16a, 16b have correspondingly larger offsets with respect to each other than in the pair of conductor ends 20c shown in FIGS. 2a-2e and 4a-4d to 6a-6d.

[0210] According to the positions of the conductor ends 16, 16a, 16b, a pin-related power distribution or area energy, i.e., a power distribution or area energy to be individually set for the group of conductor ends 18, 20c currently to be welded, can be calculated so that a homogeneous weld bead 27 is obtained. Furthermore, the process zone dimension can be measured iteratively during the welding method—in this case by measuring the dimensions of the molten pool 5 along the dimension lines M1 to M4—in order to achieve defined limit values of the bond cross-section or not to exceed the permissible bead dimension. In detail, the change in length, width and height extension is quantified during the process. As the volume of the material of the conductor ends, e.g., copper, increases during melting, the height of the pair of conductor ends 20c to be welded changes. With continued energy input, a complete melt blanket results until a lateral bead overhang occurs with sufficient melt volume (see progress in FIGS. 2b to 2e). This is directly proportional to a specific melt volume and thus to a defined bond cross-section (cross-section over which the conductor ends 16a, 16b are fully bonded together).

[0211] In detail, optical coherence tomography can thus be used to measure the change in the process zone dimension during a welding method. Based on this, a correlation to the bond cross-section can be established. As soon as the desired melt volume or the required bond cross section is available, the energy input can be stopped. In this way, a situation-dependent energy input can be implemented, which avoids scrap and increases the process capability.

[0212] FIG. 1 shows, for example, a situation in which the welding beam 33—laser beam 2—of the welding apparatus 14 is directed to the third pair of conductor ends 20c in order to weld this pair of conductor ends 20c. In this case, the introduction of the welding energy is controlled depending on the relative position of the conductor ends 16a, 16b and depending on the current size of the molten pool 5 measured inline, as shown in FIGS. 2b to 2e. As shown in FIG. 1, the second pair of conductor ends 20b has been welded shortly before, whose molten pool 5 is just cooling to a weld bead 27, and the first pair of conductor ends 20a has been welded before the first pair whose weld bead 27 has already completely solidified.

[0213] In addition to process control for setting individual target variables of the bead dimension and the bond cross-section, the illustrated embodiment of the welding apparatus 14 and the welding method also enable characterization of the welding results.

[0214] Here, geometric measurement of the weld beads 27 is carried out after complete solidification of the molten pool 5. This process step is interposed during the welding method of a bead, since solidification is not completed immediately after the emission stop. The time until complete solidification of a process zone is used to weld the pin pair following it. After solidification of the previous molten pool, the deflection device 42 of the measuring device 28, e.g., scanner optics of the OCT device 40, changes the measuring range to the last welding position during an ongoing welding method in order to analyze the length and width extension of the previous bead.

[0215] In FIG. 1, this is indicated by the dashed measuring beam 44′, which is directed onto the second pair of conductor ends 20b during welding of the third pair of conductor ends 20c in order to measure and evaluate the weld bead 27 of the second pair of conductor ends 20b. Also, the measurement signal of the measurement beam 44′ indicating at least one dimension of the weld bead 27 of the previous weld is included in the control of the energy input of the current weld. Thus, the control device 30 is adapted to control the welding energy input to the pair of conductor ends 20c currently to be welded depending on a characterization of the previous welding result.

[0216] Analogously—see the dashed measuring beam 44—the growth of the molten pool 5 is also monitored at the current welding position—here at the third air of conductor ends 20c. As soon as the molten pool 5 at the current processing position shows a critical length or width extension—e.g., shown in FIG. 2e—the emission of the laser beam 2 is stopped.

[0217] The minimum dimension of the permissible air and creepage distance LuK (i.e., the distance between adjacent welding seams 6) is used as the evaluation variable for this purpose, since the distance to the previous weld bead 27 is known. Accordingly, the dimension of the process zone extension is controlled via the energy input in order to avoid falling below the minimum required air and creepage distance LuK.

[0218] FIGS. 2a to 2e show top views of the pair of pins 1 currently being welded —pair of conductor ends 20c—with process zone dimensions at different times of the process progress including dimension lines M1 to M4. Thus, as shown in FIG. 2a, the size of the gap 46 between the conductor ends 16a, 16b, among others, can be recorded. FIGS. 2b to 2e show the increasing size of the molten pool 5 and thus of the process zone dimensions.

[0219] Direct quantification of the current relative positions of the conductor ends 16a, 16b at each current group of conductor ends 18 and direct quantification of the molten pool dimensions may be provided, thereby enabling the progress of the weld to be detected and the welding energy input to be optimally stopped or otherwise controlled.

[0220] From a process engineering point of view, optical coherence tomography offers process engineering advantages due to the evaluation of optical measured variables of the process zone dimension. Here, a measuring beam 44 is emitted in a specific wavelength. Height information is generated via the travel time of the reflected radiation. This makes it possible to detect a geometric change in the molten pool 5, which at the same time serves as an input variable for dimensioning the energy input. Thus, the process zone dimension can be quantified and also the pin positions before welding and the weld bead after welding can be measured.

[0221] Other measuring methods based on time-of-flight measurements can also be used. Basically, any measuring principle is suitable that can be used to geometrically measure different dimensions of the weld zone.

[0222] In embodiments of the welding method, inline measurement of the process zone dimensions thus takes place (during the welding method). It is possible to intervene in the power emission as soon as the specified melt volume and/or the specified bond cross-section are reached. There is a direct evaluation of evaluation variables decisive for the quality of the weld.

[0223] Advantages of the preferred embodiment of the welding method are:

[0224] quantification of the actual process zone dimension during a welding operation for situation-adjusted energy input

[0225] avoidance of excessive energy input and thus oversized melt formation as well as the risk of damage to the insulating varnish

[0226] avoidance of insufficient energy input and thus insufficient bond cross-sections

[0227] combination of pre-process, in-process and post-process analysis of the welded joint

[0228] In particular, the measurement strategy developed allows inline quantification of the process zone geometry and thus control of the energy input to achieve the required bond cross-section.

[0229] In the following, an embodiment of the welding method is explained in more detail, in which the welding energy input is controlled depending on the relative position of the conductor ends 16a, 16b to be welded. FIG. 2a and FIGS. 4a, 5a and 6a show views of a group of conductor ends 18 for this purpose, using the example of the third pair of conductor ends 20c currently to be welded in FIG. 1. FIG. 3 shows another group of conductor ends 18, for example the fifth pair of conductor ends 20e with deviating relative positions.

[0230] By means of the measuring device 28, the height offset HV, the radial offset RV and the tangential offset TV of the conductor ends 16a,16b are detected. The pin positions are characterized with respect to HV, RV and TV. Subsequently, an individual calculation of the energy distribution for the current pair of conductor ends 20c or 20e is performed by means of the control device 30.

[0231] In the case of an offset (HV, RV, TV) detected before the process start—see FIG. 3—this can be taken into account in the calculation of the required process zone dimension in order to achieve the required bond cross-sections. In addition, a pin-related energy input can be calculated as a function of the height offsets and implemented on the respective pins 1.

[0232] As shown in FIGS. 2b to 2e as well as 4b to 4d, 5b to 5d and 6b to 6d, the process zone dimension is quantified during power emission in accordance with the four exemplarily arranged measurement lines M1-M4. Depending on the process zone dimension—i.e., in particular the dimensions of the depicted weld contours 3—a back-calculation to the associated bond cross-sections is possible. Consequently, an emission stop can be stored for a specific limit value of the bond cross-section so that the pair of conductor ends 20c, 20e currently to be welded is not thermally overloaded. In addition, the welding energy input can be controlled, for example, by controlling the size of the laser spot 4.

[0233] In one embodiment, only the relative position of the conductor ends 16a, 16b is detected to control the welding energy input. In another embodiment, the relative position of the conductor ends is detected and the molten pool dimensions are quantified inline to control the welding energy input. Other embodiments have still additional parameters by which the welding energy input is controlled.

[0234] In the process indicated in FIG. 1 with the measuring beam 44′, the previous weld location is measured and used as an input variable for the control at the current weld location (post-process weld location 1=in-process weld location 2). In particular, the bead geometry of already welded pairs of conductor ends 20a, 20b (weld location 1) is detected during the welding method for the current pair of conductor ends 20c (weld location 2).

[0235] In a further embodiment, one of the pairs of conductor ends 20d, 20e to be welded next is measured in advance, e.g., still during the current welding method. For example, a leading measurement of the adjacent pins 1, i.e., in the example of FIG. 1 in particular of the fourth pair of conductor ends 20d and/or the fifth pair of conductor ends 20e—is carried out with respect to the respective relative position, i.e., one or more of the relative offsets HV, RV and TV. As a result, the detection of the relative positions can be faster, and the welding of the respective next pair of conductor ends 20d can start with the input variables of the relative positions immediately after the completion of the previous pair of conductor ends 20c.

[0236] In a further embodiment, the air and creepage distance LuK of two adjacent already welded pin pairs is determined. For example, in the welding arrangement 10 of FIG. 1, the air and creepage distance, i.e., in particular the free distance, between the weld beads 27 of the first pair of conductor ends 20a and the second pair of conductor ends 20b is determined. If the value is below a predetermined threshold or prewarning value, the energy input for the current weld is reduced. If the value is above a predetermined maximum value, the energy input may be increased to allow for a larger melt volume and thus a larger bond cross-section.

[0237] In yet another embodiment, splashes can be detected. For this purpose, instead of the coarse grid with a few dimension lines M1 to M4, a finer grid and preferably with a simultaneously shorter line length is used for the OCT process. Detection of splashes up to the closed melt blanket is possible. A fine grid with simultaneously shorter line length is used because the melt volume at the start of the process does not exceed the pin cross-section. This makes it possible to draw conclusions about splashes in the event of a significant change in the height level.

[0238] In addition to the process zone dimension, a potentially occurring emission of splashed from the process zone can be detected as further information. Splash formation can occur especially during the formation of the keyhole or an emission in the gap. If the measuring line is positioned appropriately, this can be detected by OCT and used as an evaluation variable for the process.

[0239] Further embodiments provide for a component-specific adjustment of the energy input per area. In particular, the irradiation location and/or the area energy are controlled as a function of the OCT image.

[0240] In one embodiment, the height offset HV is included as a boundary condition for this purpose. This embodiment of the welding method comprises the following steps:

[0241] s1) measurement of the clamped pin pair (for example pair of conductor ends 20c or 20e) in the initial state, see FIGS. 2a, 3, 4a, 5a, 6a, in particular by means of OCT, and identification of the height position (z-direction) and the x-y position

[0242] s2) identification or calculation of the energy distribution per pin 1 according to the xyz position of the respective pins

[0243] s3) a) controlling the surface energy according to the height difference, in particular by controlling contour length, the velocity and/or the power of the welding beam 33, in particular laser beam 2; and/or [0244] b) tracking of the focal plane according to the height difference.

[0245] In a further embodiment (may also be present in combination), the radial offset RV is included as a boundary condition for this purpose. This example of the welding method comprises the following steps:

[0246] t1) measurement by OCT or the like and identification of the gap 46

[0247] t2) calculation of the start position and geometry dimension (surface energy) of the welding beam 33 so that there is sufficient melt volume to close the gap 46

[0248] t3) a) controlling the surface energy according to the height difference, in particular by controlling position, contour length, the velocity and/or the power of the welding beam 33, in particular laser beam 2; and/or [0249] b) tracking of the focal plane according to the height difference.

[0250] The energy input is to be adjusted according to the height offset HV and the gap dimension—e.g., determined via the radial offset RV—so that a homogeneously pronounced welding seam 6/weld bead 27 is obtained.

[0251] Of course, embodiments of the invention may include all of the functions or any combinations of the foregoing embodiments.

[0252] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

LIST OF REFERENCE SIGNS

[0253] 1 pin [0254] 2 laser beam [0255] 3 welding contour [0256] 4 laser spot [0257] 5 molten pool [0258] 6 welding seam [0259] 10 welding arrangement [0260] 12 component [0261] 14 welding apparatus [0262] 16 conductor end [0263] 16a first conductor end [0264] 16b second conductor end [0265] 18 group of conductor ends [0266] 20 pair of conductor ends [0267] 20a first pair of conductor ends [0268] 20b second pair of conductor ends [0269] 20c third pair of conductor ends [0270] 20d fourth pair of conductor ends [0271] 20e fifth pair of conductor ends [0272] 22 stator [0273] 24 housing [0274] 25 clamping device [0275] 26 welding apparatus [0276] 27 weld bead [0277] 28 measuring device [0278] 30 control device [0279] 32 laser [0280] 33 welding beam [0281] 34 laser optics [0282] 36 deflecting mirror [0283] 38 optical element [0284] 40 OCT device [0285] 42 deflection device [0286] 44 measuring beam (on current weld zone) [0287] 44′ measuring beam (on previous weld zone) [0288] 46 gap [0289] HV Height offset [0290] M1 first dimension line [0291] M2 second dimension line [0292] M3 third dimension line [0293] M4 fourth dimension line [0294] LuK air and creepage distance [0295] RV radial offset [0296] TV tangential offset