Cover and device for simultaneously aligning and masking hairpins of a stator in preparation for a welding process and method for joining upper ends of hairpins of a stator

Abstract

The invention relates to a cover for simultaneously aligning and masking the hairpins of a stator in preparation for a welding process in which the upper ends of the hairpins are joined. The cover comprises a surface, in particular circular, with a top and a bottom, recesses into which an arrangement comprising the paired upper sections of two hairpins can be received, and means for aligning and clamping the paired upper sections of the two hairpins. The use of such a cover enables automatic centering and positive clamping accuracy, while simultaneously masking the hairpin pairs.Furthermore, the invention relates to a device comprising such a cover, a method for connecting upper ends of hairpins of a stator using such a cover, a stator produced according to this method, and a system comprising a stator and a cover according to the invention.

Description

[0001] The invention relates to a cover for the simultaneous alignment and masking of stator hairpins in preparation for a welding process by which upper ends of the hairpins are connected, as well as to a device comprising such a cover. Furthermore, the invention relates to a method for connecting upper ends of stator hairpins, which is carried out using a cover according to the invention, and to a stator manufactured according to such a method. Furthermore, the invention relates to a system comprising a stator and a cover according to the invention.

[0002] Methods and devices for manufacturing stators are known in the art. Stators are used in electrodynamic machines, e.g., electric motors.

[0003] In the production of electromechanical converters, especially electric motors, especially for traction drives, individual winding elements (plug-in coils, so-called “hairpins”) are produced, which are then further processed into a stator winding.

[0004] In order to achieve greater efficiency in electrical machines due to a higher fill ratio, hairpin technology was switched from round to rectangular conductor cross-sections. Within the scope of the invention, the use of any conductor cross-section is possible, for example, round or rectangular cross-sections. During the production of the winding elements, appropriate conductor sections are cut from continuous material and formed into suitable winding elements. The winding elements are then positioned on the stator and welded together at their upper ends.

[0005] To ensure this welding process is reliable and reproducible, the hairpins to be welded together must be positioned in a precisely defined position relative to each other to ensure the desired contact. Furthermore, it is desirable to cover or mask the area around the hairpin ends to prevent welding beads or waste material generated during the welding process from contacting and potentially damaging the remaining sections of the hairpins. With hairpin technology, two conductor elements are formed as a single piece in a U-shaped wire, similar to a classic hairpin.

[0006] In the typically provided two-layer winding, the ends of two individual conductor elements, hereinafter referred to as two conductor element ends, or two ends of two different hairpins, hereinafter referred to as two ends of a hairpin pair, are welded together. Beforehand, the two conductor element ends or ends of a hairpin pair to be welded are stripped of insulation and positioned relative to one another using a clamping device. The relative positioning is carried out in accordance with their desired relative arrangement after the welding operation, i.e. in the finished stator. A masking device is also typically provided. This is intended to prevent welding sparks or hot metal particles generated during the welding process from damaging the stator or the insulation of the conductors and / or destroying their functionality.

[0007] Numerous devices and methods for aligning and masking the conductor elements or hairpins of stators prior to a welding process are known in the prior art, as described, for example, in DE 10 2013 206 532 A1, DE 10 2018 103 100 A1, JP 2013 - 165 615 A, US 9 455 614 B2, JP 4 114 588 B2, and JP 2015 - 171 260 A. Only previously known devices and methods for stators manufactured using hairpin technology are described below.

[0008] For example, individual stator segments are clamped and masked sequentially within a welding ring. This involves using clamping pins, which are inserted radially into the respective stator segment and position the ends of the individual hairpin pairs relative to each other. In addition, a flat masking plate, arranged over the part of the stator not being machined, has a stop surface oriented in the z-direction for the hairpin pairs to be clamped. The disadvantage of this approach is the small number of hairpin pairs that can be machined in one and the same machine setting. Furthermore, this method is not applicable for stators with multiple welding rings.

[0009] Alternatively, full clamping and full masking are possible. In one variant, the ends of the hairpin pairs to be welded are held in two cover plates, each provided with through holes and arranged one above the other. The ends of the hairpin pairs are then aligned tangentially and radially by rotating the cover plates against each other. In the final position, the inner sides of the through holes contact the ends of the hairpin pairs in the circumferential direction.

[0010] Another well-known design for full clamping and full masking involves sheet metal strips with holes for the ends of the hairpin pairs to be welded. A radial row of hairpin pairs is inserted into the holes of two stacked strips. The sheets are then radially shifted against each other. This design is very complex, especially with regard to maintenance and repair.

[0011] The main disadvantage of these two methods, full clamping and full masking, is the risk that metal particles generated during welding can block the twisting mechanism. Furthermore, depending on the cross-sectional geometry of the hairpins to be welded, openings in the respective masking are required.

[0012] Overall, the devices and methods described in the prior art are considered relatively complex, labor-intensive, cost-intensive, and prone to failure. Furthermore, they exhibit limitations regarding the cross-sectional geometries of the hairpins, the number of hairpin pairs that can be simultaneously aligned and / or welded, and / or the number of weld rings that can be processed. Overall, the known methods are considered unsatisfactory from an economic perspective.

[0013] The invention is therefore based on the object of overcoming these and other disadvantages of the prior art and of providing a device and a method with which the welding process in the manufacture of a stator comprising hairpins can be prepared and carried out simply, cost-effectively, reliably, and reproducibly. Furthermore, the device and method should be applicable regardless of the stator design, e.g., the number of welding rings and the geometry of the hairpins.

[0014] Main features of the invention are set out in claim 1, claim 13, claim 14, claim 17, or claim 18. Embodiments are the subject of claims 2 to 12 or 15 and 16.

[0015] The problem is solved by a cover for the simultaneous alignment and masking of stator hairpins in preparation for a welding process, which connects the upper ends of the hairpins. The hairpins have two legs, and the legs have an upper section that is stripped and has an upper end. Two upper sections of legs of different hairpins are arranged in pairs. The cover according to the invention comprises i) a surface, in particular a circular one, with a top side and a bottom side, ii) recesses, - in each of which an arrangement comprising the paired upper sections of two hairpins can be accommodated and - which are arranged in a circumferential direction of the surface on concentric circular paths or sections of concentric circular paths and in radially extending rows next to one another, wherein - recesses arranged next to one another in the circumferential direction are spaced apart by a section of a radial web extending in a radial direction, - recesses arranged next to one another in the radial direction are spaced apart by a section of an annular web running between the concentric circular paths, and - a relative arrangement of the recesses corresponds to a relative end positioning which is provided for the paired upper sections of two hairpins, and iii) means for aligning and tensioning the paired upper sections of two hairpins, where - the means are arranged on the underside of the surface in the radial direction, - each means has a first end facing the underside of the surface and a second end facing away from the underside of the surface, each means being tapered towards the second end, and - the first end of each means partially overlaps with at least one of the recesses.

[0016] A number of recesses corresponds to at least a set of arrangements, each of which comprises paired upper sections of two hairpins and is to be welded together. The recesses extend in the direction of a normal from the top side to the bottom side of the surface. The normal runs perpendicular to at least part of the top side of the surface.

[0017] The area encompassed by the cover is preferably circular. Alternatively, it can be configured as a polygon, e.g., a square or rectangle. The cover can also be designed to encompass only a portion of the circularly arranged hairpins. For example, the cover can be designed to mask a semicircular portion of the hairpins.

[0018] The claimed cover is advantageously formed in one piece. Therefore, both its production and its application are particularly simple and cost-effective. The cover can be manufactured using 3D printing, in particular using metallic materials. Furthermore, the relatively simple structure of the cover enables simple, reliable, and reproducible preparation and execution of the welding operation required to connect the ends of the hairpin pairs. Thus, the cover is only moved in a normal direction so that the assemblies, comprising the paired upper sections of two hairpins, are received in the recesses. The normal direction runs parallel to the longitudinal axis of the stator to be covered and / or machined. This movement can be realized, for example, using a simple linear drive.This eliminates the need for complex and failure-prone twisting of multiple components against each other. This keeps operating costs low, as well as maintenance and repair costs.

[0019] Alignment, clamping, and masking of the hairpins are carried out simultaneously in one step. For alignment and clamping, means are arranged on the underside of the surface in the radial direction. The means, which tapers towards the second end, initially act as insertion aids for the upper sections of the hairpins into the recesses. The advantage here is that the hairpins are neither irreversibly deformed nor are their surfaces or insulation damaged. Furthermore, any positioning deviations within the entire hairpin arrangement of the stator are compensated for in a particularly simple and material-friendly manner. The means are advantageously repositioned, e.g. via a stop, above the bending points of the hairpins. Because the first end of each means partially overlaps with at least one of the recesses, automatic alignment, i.e.Centering and clamping of the hairpin pairs within the recesses is achieved in a simple, cost-effective, reliable, and reproducible manner. An external clamping station or mandrel changer is not required.

[0020] Due to the numerous design options regarding the cover material, the shape of the surface, as well as the number, shape, dimensions, and arrangement of the recesses and means, the cover according to the invention can be modified and used in a variety of ways. In particular, adaptation to the design of a variety of stators, which have different numbers of weld rings and / or cross-sectional geometries of the hairpins, can be carried out easily and cost-effectively by replacing the cover.

[0021] The recesses are advantageously rectangular, and the means for aligning and clamping are arranged in the respective corners of the recesses. The arrangement is preferably such that the means overlap the corners of the rectangles (the recesses). Thus, the means extend both along the narrow side and along the longitudinal side arranged orthogonally to this.

[0022] Preferably, the means are arranged at the intersection points of the radial webs and the annular webs. Preferably, the area of ​​the first ends of the means is larger than the area of ​​the intersection points.

[0023] Preferably, the extension of the first ends of the means in the circumferential direction is greater than the width of the radial webs (in the circumferential direction) at the position of the respective means.

[0024] Preferably, the extension of the first ends of the means in the radial direction is greater than the width of the annular webs (in the radial direction) at the position of the respective means.

[0025] Preferably, the first ends of the means cover the intersection points of the radial webs and the annular webs (when viewing the cover from the underside of the surface).

[0026] This may refer to some of the centers and recesses or radial webs and ring webs.

[0027] Preferably, the first ends of at least some means cover all four corners of at least some of the rectangular recesses.

[0028] Overall, the claimed cover achieves automatic centering and positive clamping accuracy. At the same time, the hairpin pairs are masked. This prevents or prevents damage to the stator caused by sparks and / or metal particles that may occur during the welding process, thus rendering it unusable. In particular, damage to the laminated core, the insulation material, and the mechanical components is avoided or prevented. Using the claimed cover, the welding of the upper ends of the hairpin pairs is simple, cost-effective, reliable, and reproducible, even on an industrial scale.

[0029] In one embodiment of the claimed cover, the recesses arranged on a circular path are arranged equidistantly from one another in the circumferential direction and / or the recesses of two adjacent circular paths are arranged equidistantly from one another in the radial direction. This makes the cover particularly easy to manufacture and use. The equidistantly selected distance between the recesses in the circumferential direction can be greater than the equidistantly selected distance between the recesses in the radial direction, and vice versa.

[0030] A further variant of the claimed cover provides that a first circumference of an inner side of each recess is larger than a second circumference of an outer side of an arrangement comprising the upper sections of two hairpins arranged in pairs. This makes it easier for the assemblies to be removed from the recesses after the welding process has been carried out, i.e. without jamming or tilting. This is because the weld seam or weld bead by which the upper ends of a hairpin pair are connected naturally projects somewhat beyond the outer side of the arrangement comprising the paired and welded upper sections of two hairpins. Therefore, a circumferential gap is provided (the gap runs up to the contact points of the hairpins with the means) between the inner side of each recess and the outer side of an arrangement comprising the paired upper sections of two hairpins.The width of the circumferential gap is usually ≤ 0.8 mm.

[0031] In another embodiment of the claimed cover, the radial web and / or the annular web are formed in one piece. This is particularly advantageous with regard to the manufacturing, stability, and robustness of the cover. Alternatively, the radial web and / or the annular web—depending, among other things, on the number of concentric circular paths on which the recesses are arranged—has several spaced-apart sections. This can reduce the material costs and / or weight of the cover.

[0032] In another variant of the claimed cover, the means are arranged on the radial webs extending in the radial direction. Such an arrangement is simple to implement and advantageous for the stability and application of the cover. Particularly in the case of rectangular recesses, the alignment, self-centering, and clamping of the paired upper sections of two hairpins can be easily achieved. This is because the means for alignment and clamping can be arranged on the radial webs such that all four corners of the recesses each have a partial overlap with the first end of one of the means. The corners of the recesses can also be rounded.

[0033] In another embodiment of the cover, the first end of each means partially overlaps at least two recesses. This can be achieved, for example, if the cover comprises rectangular recesses and, for example, truncated cones or hemispheres are provided as the means for alignment and clamping, which are arranged on the radial webs. The first ends of the truncated cones or hemispheres can be designed as circular surfaces or annular.

[0034] A further embodiment of the claimed cover provides that a surface of the first end of each means is integrally connected to the underside of the surface or lies in the same plane as the upper side of the surface. In the first case, the cover can be manufactured, for example, in several steps. First, the surface of the cover and the means are manufactured. Then, each means is arranged as desired with the surface of the first end on the underside of the surface, followed by a material-to-material connection of the surface of the first end of each means to the underside of the surface. This has the advantage that the cover can be manufactured individually as required. The material-to-material connection can be achieved, for example, using a special adhesive or a welding operation, depending on the type of material selected for the surface and means. However, the cover can also be manufactured in a single step. For this purpose, for example,An injection molding process or a 3D printer can be used. Thus, the manufacturing method for the cover can be advantageously selected depending on the desired application.

[0035] In another variant of the claimed cover, at least one, preferably several, in particular each means has a contour that can be derived from a pyramid, a cone and / or a sphere. The term "derivable" in this context means that the contour is designed from at least one geometric body selected from the group consisting of a pyramid, a cone and a sphere. The "derivation" occurs by modifying the at least one geometric body, in particular by capping an upper end or dividing it. The modification is carried out in accordance with the requirements associated with the cover to be manufactured. It is particularly simple and therefore advantageous if at least one, preferably several, in particular each means is a four-sided truncated pyramid, a six-sided truncated pyramid, a truncated cone or a hemisphere.

[0036] Regardless of their contour, the means can be designed as a solid body or as a hollow body. Thus, the surface of the first end of a means can be designed, for example, as a circular or polygonal surface or as a circular or polygonal ring.

[0037] Another embodiment of the claimed cover provides for its manufacture using a metallic material and / or a ceramic material. Depending on the application of the cover and the cost framework for its manufacture, the composition of its material can be selected from a relatively wide range of metallic and ceramic materials. Manufacturing from sheet steel, especially from a commercially available steel, is comparatively cost-effective.

[0038] The surface of the means can be designed to reduce friction, in particular coated. The surface of the means can be hardened or have a coating that is harder than the solid material.

[0039] In another variant of the claimed cover, it is manufactured using a 3D printing process or an injection molding process. This type of production is particularly fast and precise. The injection molding process can be, for example, a ceramic powder injection molding process or a metal powder injection molding process.

[0040] The object is further achieved by a device for the simultaneous alignment and masking of hairpins of a stator in preparation for a welding process by which upper ends of the hairpins are connected. Each hairpin has a first leg and a second leg, each leg having an upper section which is stripped and has an upper end. Furthermore, the upper section of the first leg of a first hairpin and the upper section of the second leg of a second hairpin are arranged in pairs. The claimed device comprises a cover according to one of the embodiments described above and a drive for moving the cover in a normal direction.

[0041] The normal direction runs parallel to a longitudinal axis of the stator to be covered and / or machined.

[0042] The device according to the invention allows the welding of the upper ends of the hairpins of a stator to be prepared and carried out in a simple, cost-effective, reliable, and reproducible manner. Furthermore, the claimed device is particularly simple and inexpensive to manufacture and use. In particular, its essential components, the cover described above and its embodiments, as well as the drive for moving the cover vertically up and down, are simple and inexpensive to manufacture and use. Modification and / or replacement of the cover is possible simply, quickly, and cost-effectively if necessary, i.e., depending on the stator and hairpin geometry. A wide variety of stators can be machined using the claimed device, regardless of the number of welding rings and the cross-sectional geometry of the hairpins. Hairpins with a rectangular, square, triangular, or round cross-section are possible, for example.The drive is also easily replaceable or expandable. This makes the device versatile and adaptable, even for industrial production.

[0043] In one embodiment of the device, the drive comprises a linear drive. The linear drive is, for example, a direct drive, a spindle drive, or a toothed belt drive. The linear drive has a high degree of precision, i.e., repeatability. The tolerance of the linear drive is preferably ± 0.04 mm, particularly preferably ± 0.003 mm.

[0044] Furthermore, the object is achieved by a method for connecting the upper ends of hairpins of a stator using a welding process. Each hairpin has a first leg and a second leg, each leg having an upper section that is stripped and has an upper end. Furthermore, the upper section of the first leg of a first hairpin and the upper section of the second leg of a second hairpin are arranged in pairs. The claimed method comprises the steps: i) simultaneous alignment and masking of arrays each comprising paired upper sections of two hairpins, using a cover according to one of the embodiments described above, wherein the cover is lowered in a normal direction until at least upper ends of the paired upper sections of the hairpins are received in recesses of the cover, ii) carrying out the welding operation, and iii) Removing the cover in a direction opposite to the normal direction.

[0045] Various welding methods can be used for the welding process, such as tungsten inert gas welding (TIG) and spot welding.

[0046] The normal direction runs parallel to a longitudinal axis of the stator to be covered and / or machined.

[0047] In the claimed method, the alignment, clamping, and masking of the hairpins are carried out simultaneously in a single step. Means for alignment and clamping are arranged in a radial direction on an underside of the cover. The means, which taper towards a second end, initially act as insertion aids for the upper sections of the hairpins into recesses in the cover. This is advantageous in that the hairpins are neither irreversibly deformed nor are their surfaces or insulation damaged. Furthermore, any deviations within the entire hairpin arrangement of the stator are compensated for in a particularly simple and material-friendly manner. The means are advantageously positioned above the bending points of the hairpins.

[0048] The method is particularly robust and less prone to failure due to the small number and comparatively simple design of the required components as well as the small number and relatively simple implementation of the method steps. The essential components required for the method, the cover described above and its embodiments as well as the drive for moving the cover vertically up and down, are simple and inexpensive to manufacture and use. Modification and / or replacement of the cover is possible easily, quickly and inexpensively if necessary, i.e. depending on the stator and hairpin geometry. The claimed method can be used to machine a large number of stators which can differ in the number of welding rings and / or the cross-sectional geometry of the hairpins. For example, hairpins with a rectangular, square, triangular or round cross-section are possible.The drive is also easily replaceable or expandable, making the device versatile and adaptable.

[0049] The claimed method allows for the preparation and implementation of welding the upper ends of the hairpins of a stator in a simple, cost-effective, reliable, and reproducible manner. In particular, automatic centering and positive clamping accuracy of the hairpin pairs are achieved. The method is also feasible on an industrial scale.

[0050] In one embodiment of the method, the lowering and removal of the cover is carried out by means of a drive comprising a linear drive. The linear drive can be, for example, a direct drive, a spindle drive, or a toothed belt drive. The linear drive has a high degree of precision, i.e., repeatability. The tolerance of the linear drive is preferably ± 0.04 mm, particularly preferably ± 0.003 mm.

[0051] A further variant of the method provides that the alignment comprises a radial alignment step and a tangential alignment step. The two alignment steps are carried out simultaneously. The radial alignment step comprises radial warping or clamping, i.e. in the radial direction. The tangential alignment step comprises lateral warping or clamping, i.e. in the circumferential direction. After alignment, a zero gap plane, which is oriented in the circumferential direction, and an alignment plane, which is oriented in the radial direction, are arranged orthogonally to one another. The first end of each means partially overlaps with at least one of the recesses. In this way, the simultaneous, automatic alignment in the radial and tangential directions, i.e. automatic centering, and clamping of the hairpin pairs within the recesses is achieved in a simple, cost-effective, reliable and reproducible manner.In particular, the number of process steps and thus the susceptibility to failure are advantageously reduced. The process is therefore particularly simple and quick to implement.

[0052] In another embodiment of the method, the cover is lowered until at least the upper ends of the paired upper sections of the hairpins are guided through the recesses in the cover. This is particularly advantageous because the welding of the upper ends of the stator hairpins can be carried out particularly easily and precisely.

[0053] The object is further achieved by a stator comprising hairpins. Each hairpin has a first leg and a second leg, each leg having an upper section which is stripped and has an upper end. Furthermore, the upper section of the first leg of a first hairpin and the upper section of the second leg of a second hairpin are arranged in pairs, wherein their upper ends are welded. The claimed stator is produced by a method according to one of the embodiments described further above. It is characterized in particular by its high-precision processing, in particular with regard to the alignment of the arrangements, comprising the upper sections of two hairpins arranged in pairs, the upper ends of which are welded. It can be produced particularly easily, inexpensively and reproducibly, i.e. even on an industrial scale.

[0054] Furthermore, the object is achieved by a system comprising a stator, which in turn comprises hairpins. The hairpins have two legs, and the legs have an upper section which is stripped and has an upper end. Two upper sections of legs of different hairpins are arranged in pairs. In addition to the stator, the claimed system comprises a cover according to one of the exemplary embodiments described above. At least the upper ends of the paired upper sections of the hairpins are received in recesses in the cover. Advantageously, the design of the cover is adapted to the stator and hairpin geometry. The claimed system is transportable, e.g. in the event that the upper ends of the hairpins are to be connected by means of a welding process at another location.The cover therefore serves not only to align and mask the hairpins in preparation for the welding process, but also as a transport safeguard.

[0055] The means of the cover can be convex outward toward the opening 12. However, the means 18 can also be concave inward toward the opening 12. The means 18 can also be designed such that their edges extend in a straight line when viewed toward the top side 11a, i.e., without any curvature.

[0056] The invention also includes a cover that only covers an angular range, e.g. 90°, of the 360° rings on hairpins.

[0057] The method is not limited to hairpin-shaped winding wires. The method according to the invention can also be a method for connecting the ends of winding wires, which may or may not be hairpins, of a stator using a welding process. where the winding wires have legs, and the legs have an upper portion which is stripped and has an upper end, and two upper sections of legs of different winding wires are arranged in pairs, comprehensive the steps: simultaneous alignment and masking of arrangements each comprising paired upper sections of two winding wires, using a cover according to one of the embodiments described above, wherein the cover is lowered in a normal direction until at least upper ends of the paired upper sections of the winding wires are received in recesses in the cover, Carrying out the welding process, and Remove the cover in a direction opposite to the normal direction.

[0058] The winding wires can, for example, be pin-shaped.

[0059] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. They show: Fig. 1 A stator comprising a laminated core and hairpins in an overall arrangement; Fig. 1a A partial enlargement of the overall arrangement of the hairpins from Fig. 1; Fig. 2 A section of the overall arrangement of the hairpins of the stator, accommodated in recesses of a cover according to the invention; Fig. 2a A partial plan view of an upper side of the cover according to the invention, in whose recesses hairpins are accommodated; Fig. 2b A partial enlargement of Fig. 2a; Fig. 3 A partial perspective view of an underside of an embodiment of the cover according to the invention; Fig. 3a A partial plan view of the embodiment from Fig. 3; Fig. 4 A top view of 2 upper ends of a hairpin arrangement; Fig. 4a A top view of the arrangement from Fig. 4 in the state accommodated in a recess; and Fig. 4b A representation corresponding Fig. 4a for an alternative cover.

[0060] In Fig. 1 shows a stator 30 comprising a laminated core 31 and hairpins 20 in an overall arrangement, wherein the hairpins 20 have a rectangular cross-sectional geometry. The laminated core 31 can be made, for example, from a sheet steel, in particular a commercially available one. The hairpins 20 are inserted with a lower end 24 into circumferential grooves of the laminated core 30, the grooves not being shown. The hairpins 20 are typically made of copper or a copper-containing material and, except for an upper section 22, are provided with an insulating layer.

[0061] Each hairpin 20 has legs 21, each leg 21 having an upper section 22. The latter is stripped and has an upper end 23. Furthermore, the upper sections 22 of two hairpins 20 are arranged in pairs. In Fig. 1a is a partial enlargement of the overall arrangement of the hairpins 20 from Fig. 1. Arrangements 13 comprising the paired upper sections 22 of two hairpins 20 are clearly visible.

[0062] Fig. 2 shows a section of the overall arrangement of the hairpins 20 of the stator 30, accommodated in rectangular recesses 12 of a cover 10 according to the invention with a circular surface 11. The latter comprises an upper side 11a ( Fig. 2a) and a subpage 11b ( Fig. 3). Alternatively, it can also be designed as a freeform or polygon, e.g., a square or rectangle. In other words, the cover 10 is flat.

[0063] The number of recesses 12 corresponds to the number of arrangements 13 (pairs at the upper ends 23 of the hairpins 20). Furthermore, the recesses 12 arranged on a circular path are arranged equidistant from one another in the circumferential direction U, and the recesses 12 of two adjacent circular paths are arranged equidistant from one another in the radial direction R. This makes the manufacture and application of the cover 10 particularly simple. Furthermore, a first circumference 12a of an inner side of each recess 12 is larger than a second circumference 13a of an outer side of an arrangement 13.

[0064] The arrangements 13 can be removed from the recesses after the welding process without jamming or tilting. A width or gap between the inner side 12a of each recess 12 and the outer side 13a of an arrangement 13 is typically ≤ 0.8 mm. The radial webs 15 and the annular webs 17 are formed in one piece. This is particularly advantageous with regard to the manufacturing, stability, and robustness of the cover. Alternatively, the radial web 15 and / or the annular web 17 can have several spaced-apart sections.

[0065] The cover 10 is advantageously formed as a single piece. Therefore, both its manufacture and application are particularly simple and cost-effective. The comparatively simple structure of the cover 10 enables simple, reliable, and reproducible preparation and execution of the welding operation required to connect the upper end 23a of the first hairpin 21 to the upper end 23b of the second hairpin 21.

[0066] Thus, it can be provided that the cover 10 is moved only in a normal direction N so that the assemblies 13, comprising the paired upper sections 22a, 22b of two hairpins 20a, 20b, are received in the recesses 10. The normal direction N runs parallel to the longitudinal axis of the stator 30 to be covered and / or machined. Alignment, clamping, and masking of the hairpins 20a, 20b take place simultaneously in one step. Means 18 for alignment and clamping are arranged on the underside 11b of the surface 11 in a radial direction R. The means 18 tapered towards a second end 18b initially serve as insertion aids for the paired upper sections 22a, 22b of the hairpins 20a, 20b into the recesses 12. The hairpins 20a, 20b are neither irreversibly deformed nor is their surfaces or insulation damaged.In addition, any deviations within the overall arrangement of the hairpins 20 of the stator are compensated for in a particularly simple and material-friendly manner. A stop (or an end of the movement of the cover) of the means 18 advantageously occurs above the bending points of the hairpins 20a, 20b. Because the first end 18a of each means 18 in the present case partially overlaps with at least two of the recesses 12, automatic alignment, i.e., centering, and clamping of the arrangements 13 within the recesses 12 is achieved in a simple, cost-effective, reliable, and reproducible manner. At the same time, the hairpins 20 are masked. This avoids or prevents the stator 30 from being damaged by sparks and / or metal particles that may arise during the welding operation, thus rendering it unusable.

[0067] It can be provided that first ends 18a of at least some means 18 overlap with four of the recesses 12 (middle two rows of the means 18).

[0068] In Fig. 2a shows a partial plan view of this overall arrangement of the hairpins 20 of the stator 30 and in Fig. 2b shows a partial enlarged top view of this overall arrangement. Both figures illustrate that the cover 10, particularly due to the presence of the means 18, achieves automatic centering and positive clamping accuracy. Thus, using the cover 10, stators 30 comprising hairpins 20 can be manufactured, which are characterized in particular by high-precision processing with regard to the alignment of the arrangements 13.

[0069] Fig. 3 shows a partial perspective view of an underside 11b of an embodiment of the cover 10 according to the invention. In Fig. 3a is a partial plan view of the embodiment of Fig. 3. The cover 10 can be manufactured using a metallic material and / or a ceramic material, depending on the application of the cover and the cost framework for its production. Manufacturing from sheet steel, especially from a commercially available steel, is relatively cost-effective.

[0070] In the Fig. 3 and Fig. 3a, the design of the underside 11b of the cover 10 is clearly visible: The radial web 15 and the annular web 17 are each formed as a single piece. The means 18 are arranged on the radial webs 15 running in the radial direction R, in such a way that all four corners of the recesses 12 each partially overlap with the first end 18a of one of the means 18. Furthermore, all the means 18 are designed as truncated cones, for example. A comparable arrangement is possible using hemispheres as the means 18. Alternatively, the means 18 can be designed, for example, as a multi-sided, in particular four- or six-sided, truncated pyramid. In the present embodiment, the means 18 can be designed as a solid body or as a hollow body. Thus, the first ends 18a of the truncated cones can be designed as circular surfaces or annular.Independently of this, a surface 19 of the first end 18a of each means 18 is integrally connected to the underside 11b of the surface 11. For a cover 10 according to this embodiment, the surface 11 of the cover 10 and the means 18 are first manufactured. Then, each means 18 is arranged with the surface 19 of the first end 18a on the underside 11b of the surface 11, followed by a integral connection of the surface 19 of the first end 18a of each means 18 to the underside 11b of the surface 11. Thus, the cover 10 can be individually manufactured as required. The integral connection can be achieved, for example, using a special adhesive or a welding operation, depending on the type of materials selected for the surface 11 and the means 18. As in the Fig. 3 and Fig. As can be seen in Figure 3a, the extension of the first ends 18a of the means 18 in the circumferential direction U can be greater than a width 35 (in the circumferential direction U) of the radial webs 15 at the position of the respective means. Likewise, the extension of the first ends 18a of the means 18 in the radial direction R can be greater than a width 36 (in the radial direction R) of the annular webs 17 at the position of the respective means 18.

[0071] Fig. Figure 4 illustrates a pair of upper ends 23 of hairpins before they have been aligned by the inventive cover or method. Fig. Figure 4a, on the other hand, illustrates the upper sections 22 or upper ends 23 in the state received in the recess 12. When the cover 10 is "placed" or lowered onto the hairpins, the hairpins are guided along the means 18 and "steered" into the recesses 12. In this configuration, they are correctly positioned and masked.

[0072] In the example of Fig. 4a, the means 18 are curved (or convex) outwards towards the opening 12. In the example of Fig. 4b, the means 18 are curved (or concave) inwards towards the opening 12.

Claims

[1] Cover (10) for simultaneously aligning and masking hairpins (20) of a stator (30) in preparation for a welding process by which upper ends (23) of the hairpins (20) are connected, wherein - the hairpins (20) have two legs, and the legs (21) have an upper section (22, 22a, 22b) which is stripped and has an upper end (23, 23a, 23b), and - two upper sections (22) of legs (21) of different hairpins (20) are arranged in pairs, where the cover (10) comprises i) a surface (11) with a top side (11a) and a bottom side (11b), ii) recesses (12), - in each of which an arrangement (13), comprising the paired upper sections (22a, 22b) of two hairpins (20, 20a, 20b), can be recorded and which are arranged side by side in a circumferential direction (U) of the surface (11) on concentric circular paths or sections of concentric circular paths and in radially extending rows, where - recesses (12) arranged next to one another in the circumferential direction (U) are spaced apart by a section (14) of a radial web (15) extending in a radial direction (R), - recesses (12) arranged next to one another in the radial direction (R) are spaced apart by a section (16) of an annular web (17) extending between the concentric circular paths, and - a relative arrangement of the recesses (12) corresponds to a relative end positioning which is provided for the paired upper sections (22a, 22b) of two hairpins (20a, 20b), and iii) means (18) for aligning and tensioning the paired upper sections (22a, 22b) of two hairpins (20a, 20b), where - the means (18) are arranged on the underside (11b) of the surface (11) in the radial direction (R), - each means (18) has a first end (18a) facing the underside (11b) of the surface (11) and a second end (18b) facing away from the underside (11b) of the surface (11), each means (18) being tapered towards the second end (18b), and - the first end (18a) of each means (18) partially overlaps with at least one of the recesses (12). [2] Cover (10) according to claim 1, wherein the recesses (12) arranged on a circular path are arranged equidistant from one another in the circumferential direction (U) and / or the recesses (12) of two adjacent circular paths are arranged equidistant from one another in the radial direction (R). [3] Cover (10) according to claim 1 or 2, wherein a first circumference of an inner side (12a) of each recess (12) is larger than a second circumference of an outer side (13a) of an arrangement (13) comprising the paired upper sections (22a, 22b) of two hairpins (20a, 20b). [4] Cover (10) according to one of claims 1 to 3, wherein the radial web (15) and / or the annular web (17) is formed in one piece. [5] Cover (10) according to one of claims 1 to 4, wherein the means (18) are arranged on the radial webs (15) extending in the radial direction (R). [6] Cover (10) according to one of claims 1 to 5, wherein the first end (18a) of each means (18) partially overlaps with at least two recesses (12). [7] Cover (10) according to one of claims 1 to 6, wherein a surface (19) of the first end (18a) of each means (18) - is integrally connected to the underside (11b) of the surface (11). [8] Cover (10) according to one of claims 1 to 7, wherein at least one means (18) has a contour which can be derived from a pyramid, a cone and / or a sphere. [9] Cover (10) according to claim 8, wherein at least one means (18) is a four-sided truncated pyramid, a six-sided truncated pyramid, a truncated cone or a hemisphere. [10] Cover (10) according to one of claims 1 to 9, manufactured using a metallic material and / or a ceramic material. [11] Cover (10) according to one of claims 1 to 10, manufactured using a 3D printing process or an injection molding process. [12] Cover (10) according to claim 11, wherein the injection molding process is a ceramic powder injection molding process or a metal powder injection molding process. [13] Device for the simultaneous alignment and masking of hairpins (20) of a stator (30) in preparation for a welding process by which upper ends (23) of the hairpins (20) are connected, where - the hairpins (20) have two legs, and the legs (21) have an upper section (22, 22a, 22b) which is stripped and has an upper end (23, 23a, 23b), and - two upper sections (22) of legs (21) of different hairpins (20) are arranged in pairs, comprising i) a cover (10) according to one of claims 1 to 12 and ii) a drive for moving the cover (10) in a normal direction (N). [14] Method for connecting upper ends (23) of hairpins (20) of a stator (30) using a welding process, where - the hairpins (20) have two legs, and the legs (21) have an upper section (22, 22a, 22b) which is stripped and has an upper end (23, 23a, 23b), and - two upper sections (22) of legs (21) of different hairpins (20) are arranged in pairs, comprising the steps: i) simultaneous alignment and masking of arrangements (13) each comprising paired upper sections (22a, 22b) of two hairpins (20a, 20b), using a cover (10) according to one of claims 1 to 12, wherein the cover (10) is lowered in a normal direction (N) until at least upper ends (23a, 23b) of the paired upper sections (22a, 22b) of the hairpins (20a, 20b) are received in recesses (12) of the cover (10), ii) carrying out the welding operation, and iii) removing the cover (10) in a direction opposite to the normal direction (N). [15] The method of claim 14, wherein the aligning comprises a radial alignment step and a tangential alignment step, and wherein the two alignment steps are performed simultaneously. [16] Method according to claim 14 or 15, wherein the lowering of the cover (10) takes place until at least the upper ends (23a, 23b) of the paired upper sections (22a, 22b) of the hairpins (20a, 20b) are passed through the recesses (12) of the cover (10). [17] System, comprehensive i) a stator (30), comprising hairpins (20), wherein - the hairpins (20) have two legs, and the legs (21) have an upper section (22, 22a, 22b) which is stripped and has an upper end (23, 23a, 23b), and - two upper sections (22) of legs (21) of different hairpins (20) are arranged in pairs, and ii) a cover (10) according to one of claims 1 to 12, wherein at least the upper ends (23a, 23b) of the paired upper sections (22a, 22b) of the hairpins (20a, 20b) are received in recesses (12) of the cover (10), so that the hairpins each received in a recess (12) of the cover can be welded to one another. [18] Method for connecting ends (23) of winding wires (20) of a stator (30) using a welding process, where - the winding wires (20) have legs, and the legs (21) have an upper section (22, 22a, 22b) which is stripped and has an upper end (23, 23a, 23b), and - two upper sections (22) of legs (21) of different winding wires (20) are arranged in pairs, comprehensive the steps: iv) simultaneous alignment and masking of arrangements (13) each comprising paired upper sections (22a, 22b) of two winding wires (20a, 20b), using a cover (10) according to one of claims 1 to 12, wherein the cover (10) is lowered in a normal direction (N) until at least upper ends (23a, 23b) of the paired upper sections (22a, 22b) of the winding wires (20a, 20b) are received in recesses (12) of the cover (10), v) Carrying out the welding process, and Removing the cover (10) in a direction opposite to the normal direction (N).

Images