Method and device for producing a stator body of an axial flux machine, and axial flux machine
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-04-22
- Publication Date
- 2026-03-11
AI Technical Summary
Current manufacturing processes for stator bodies of axial flux machines are time-consuming and costly due to the need for complex milling and post-processing to prevent conductive burrs and ensure smooth wire winding, and existing methods require significant investment in specialized tools.
A method and device that use a sheet metal strip and a punching stamp unit to create recesses with adjustable widths by multiple punching strokes, allowing for the formation of linear grooves with freely selectable edge courses and sizes, enabling a simpler, cost-effective, and time-saving production process.
This approach allows for the efficient and cost-effective manufacturing of stator bodies with adjustable groove widths and shapes, reducing electromagnetic losses and manufacturing effort, while enabling precise assembly and assembly process optimization.
Smart Images
Figure DE2024100353_07112024_PF_FP_ABST
Abstract
Description
[0001] Method and device for producing a stator body of an axial flux machine, and axial flux machine
[0002] The invention relates to a method and a device for producing a stator body of an axial flux machine. Furthermore, the invention relates to the axial flux machine itself.
[0003] Axial flux machines and transverse flux machines are widely known. The special feature of these machines is that they have a circumferential winding that runs concentrically with the shaft of the axial flux machine's rotor. Various manufacturing processes are known for producing the stator body of axial flux machines.
[0004] One method involves winding the stator body from sheet metal. This creates essentially wedge-shaped stator teeth. The winding is housed in slots between the stator teeth. For this purpose, the winding is placed in a so-called winding package on the stator teeth and above the slots and then inserted axially into the slots. To ensure this without damage, it is advantageous for the stator teeth to have rounded edges so that the stator teeth do not impair the insulation of the winding wires.
[0005] Corresponding radii 11 can be seen in Figure 1 on the stator body 1 shown there on the stator teeth 10. Such radii are often produced by milling. However, such a milling process also has disadvantages: the formation of burrs causes individual sheet metal layers to become conductively connected to one another, which can lead to greatly increased electromagnetic losses in the stator due to the formation of eddy currents. To avoid this, the stator body must be etched after milling and thus undergoes extensive cleaning. Accordingly, milling and the necessary post-processing are time-consuming and costly. Patent EP 2 722 976 B9 shows an alternative manufacturing implementation in which the radius on the stator tooth is approximated by steps at the height of the sheet metal during punching using several stepped punch-die combinations with transverse movement to the feed direction.
[0006] The specific design of the stator teeth with radii is explained below. The punch and die are designed for the smallest required slot width, as indicated in Figures 2 and 3. Figure 2 shows a stator body 1 in plan view, and Figure 3 shows detail A from Figure 2 in an enlarged view.
[0007] Here it can be seen that the stator body 10 is formed by a roll 15 of a thin sheet metal strip, wherein the sheet metal strip has recesses at defined intervals, which together form radially extending linear grooves 17 at defined angular positions 16.
[0008] Figure 3 shows the radially inner region of some stator teeth 10. Individual lamination layers 18 are indicated in a radially inner end region of one of the stator teeth 10 to illustrate that the stator body 1 is formed from a roll of rolled-up lamination strip. It is also evident here that the stator teeth 10 have radii 11 on their circumferential boundary edges to facilitate the insertion of wire windings and to prevent damage to the wire insulation. To form these radii 11, the lamination layers 18, which form a corresponding groove 17 in a region of the radii 11, must have recesses of different sizes as adapted windings 14.
[0009] It is necessary that at least the smallest groove width 12 is realized, up to the largest groove width 13.
[0010] In this regard, patent EP 2 722 976 B9 teaches a device and method for producing recesses in sheet metal strips from which stator bodies are wound. The device utilizes a plurality of tool inserts of varying widths that are movable transversely along the feed direction of the sheet metal strip. The upper punch and lower die assemblies are advanced by an actuator, so that relatively wider punches and dies are used to produce the first several innermost layers and the last several outermost layers.
[0011] But even in this manufacturing process, the manufacturing effort as well as the investment expenditure for providing the necessary tools remains considerable.
[0012] From DD 257 335 A5 a method for producing a stator body of an axial flux machine is known, in which two punching strokes are carried out in order to produce two separate recesses by means of one punching stroke each.
[0013] Based on this, the present invention is based on the object of providing a method and a device for producing a stator body of an axial flux machine as well as an axial flux machine itself, which enable the production of the stator body in a simple, cost-effective and time-saving manner.
[0014] This object is achieved by the method for producing a stator body of an axial flux machine according to claim 1 and by the device for producing a stator body of an axial flux machine according to claim 11.
[0015] Advantageous embodiments of the method are specified in the dependent claims 2 to 10. In addition, an axial flow machine according to claim 12 is provided.
[0016] The features of the claims may be combined in any technically reasonable manner, whereby the explanations from the following description as well as features from the figures, which comprise supplementary embodiments of the invention, may also be considered. Within the context of the present invention, the terms "radial," "axial," and "circumferential direction" always refer to the axis of rotation of a rotor of the axial flux machine, which is positioned next to the stator body of the axial flux machine.
[0017] The invention relates to a method for producing a stator body of an axial flux machine, in which a sheet metal strip and a punching unit are provided, and sheet metal areas are punched out of the sheet metal strip by means of the punching unit at defined longitudinal positions such that the sheet metal strip has recesses. The sheet metal strip having the recesses is rolled up such that the recesses are located at defined angular positions in the roll of the sheet metal strip, and recesses arranged at common angular positions form linear grooves extending in the radial direction.At least one recess is created by a first punching stroke and a second punching stroke in such a way that with the first punching stroke a first boundary edge is created that bounds the recess along the longitudinal direction of the sheet metal strip, with the second punching stroke a second boundary edge is created that bounds the recess along the longitudinal direction of the sheet metal strip, and the two boundary edges are at a greater distance from one another along the longitudinal direction of the sheet metal strip than at least one further recess in the sheet metal strip.
[0018] The arbitrary design of a width of the at least one recess, ie the distance between the two boundary edges of the at least one recess, has the advantage that a course of a groove edge of the linear grooves running in the radial direction can be freely selected.
[0019] After the recesses have been created, the sheet metal strip further comprises a longitudinally running strip of material from which individual webs separate the recesses from one another.
[0020] In an advantageous embodiment of the method described, several recesses are produced by two punching strokes, so that these recesses have a larger size or extension with respect to the longitudinal direction of the sheet metal strip.
[0021] A larger size or extension with respect to the longitudinal direction of the sheet metal strip of a larger recess relates in proportion to a smaller recess which, when the sheet metal strip is rolled up, is located at the same angular position as the larger recess, so that the smaller recess and the larger recess together form a stepped groove.
[0022] By arranging windings in the slots of the stator body, the stator is essentially completed.
[0023] Advantageously, the first punching stroke and the second punching stroke are applied to the same recess and a width of the same recess can be changed by changing a position of the first boundary edge generated by means of the first punching stroke along the longitudinal direction of the sheet metal strip and / or by changing a position of the second boundary edge generated by means of the second punching stroke along the longitudinal direction of the sheet metal strip.
[0024] Advantageously, the position of the first boundary edge and / or the position of the second boundary edge can be changed in such a way that any desired shape contours of the same recess can be produced.
[0025] The first punching stroke and the second punching stroke can be carried out with the same punching punch, whereby after the first punching stroke has been carried out, a relative feed movement is carried out between the sheet metal strip and the punching punch unit, and then the second punching stroke is carried out. A wider or larger recess is created accordingly by the first punching stroke and the second punching stroke being carried out with the same punch at different longitudinal positions on the sheet metal strip, whereby the cutting areas of the first punching stroke and the second idle stroke at least partially overlap each other. This overlap area or overlap area varies depending on the desired groove width. The relative feed movement between the sheet metal strip and the punching punch unit can be carried out by rotating the wound roll of the sheet metal strip.
[0026] Alternatively, or in addition, the relative feed movement between the sheet metal strip and the punching and die unit can be implemented by a translational relative movement between the rolled-up roll of the sheet metal strip and the punching and die unit. Thus, the roll can be moved translationally and / or the punching and die unit can be moved translationally; if necessary, this can be combined with the rolled-up roll of the sheet metal strip.
[0027] The translational relative movement can be realized, for example, by means of a linear unit that moves the rolled-up roll translationally.
[0028] A further alternative embodiment of the method provides that the first punching stroke is performed with a first punching punch, and the second punching stroke is performed with a second punching punch. To produce several recesses of different sizes for each recess, a relative movement is performed between the first punching punch and the second punching punch. In this case, the punching punch unit has two punches.
[0029] Both punching dies are offset from each other along the longitudinal direction of the sheet metal strip in order to create the two boundary edges.
[0030] To determine the positions of the boundary edges, the method can be carried out in such a way that, before carrying out the first punching stroke, the target size Ga of the recess to be punched out along the longitudinal direction of the sheet metal strip is determined. The difference D between the target size Ga and the size Wb of an adjacent recess located at the same angular position in the radially inner adjacent turn of the roll of the sheet metal strip can then be determined. In addition, a theoretical distance A can be determined which depends on a number of linear grooves running in the radial direction and / or a current position of the rolled-up sheet metal strip and / or a sheet thickness of the sheet metal strip and which would result from the adjacent recess without enlarging the recess along the longitudinal direction of the sheet metal strip.From this, starting from the first boundary edge of a previously created recess adjacent to the sheet metal strip along the longitudinal direction, a path Sv of a feed movement of the sheet metal strip can be determined, which results from:.
[0031] Sv = A + Wb -D / 2. The first punching stroke can be performed at the position on the sheet metal strip resulting from the feed movement of the sheet metal strip with the path Sv.
[0032] By determining the target size Ga of the recess to be punched, the radius of the groove is adjusted by graduating the edges of several rolled sheet metal layers at an angular position. The theoretical distance A, which would result from the adjacent recess without enlarging the recess along the longitudinal direction of the sheet metal strip, depends on the radial position of the recess in question in the roll.
[0033] Before executing the second punching stroke, a position of the second boundary edge relative to a position of the first boundary edge can be determined by adding the target size Ga of the recess to a position dimension of the first boundary edge. The second punching stroke can be performed at this position to produce the second boundary edge.
[0034] Alternatively, or as a control calculation, the term Wb + D / 2 can also be added to the position measurement of the first boundary edge. The distance is defined from the roll.
[0035] Accordingly, the recess widening is symmetrical. However, the invention does not exclude an asymmetrical design of the recess widening. This asymmetrical design of the recess widening can be achieved, for example, as follows: By moving the rotational axis or the translational movement through the linear axis, the position for each punching stroke can be freely selected. This makes it possible to design the width of a groove created from two punching strokes in such a way that an asymmetric relationship arises around the center axis of the grooves. Furthermore, as a logical consequence, it is also possible to design the groove edge, which is created by arranging individual layers separately selected in a geometry, in any desired shape. The different design of the grooves along their course is particularly useful here in order to implement targeted poka-yoke features for further assembly processes.
[0036] Distances between adjacent recesses for forming linear radial grooves can be adjusted by a translational relative movement between the roller and the punching unit.
[0037] For example, the produced roll is moved linearly relative to the punching unit, in particular, away from it. The roll produced from the wound sheet metal strip should have linear, radially extending grooves formed by the radially overlapping recesses. However, this requires that the distances between adjacent recesses along the circumferential direction in a radially further inner section of the sheet metal strip in the roll must be created significantly closer to one another than the distances between adjacent recesses along the circumferential direction that are arranged radially further outward in the roll.
[0038] Accordingly, it must be ensured that the distances between adjacent recesses become increasingly larger throughout the rolling and punching process. This increase in distance can be achieved by a translational relative movement between the roller and the punching unit, for example by a linear unit that moves the roller in relation to the punching unit. A further aspect of the present invention is a device for producing a stator body of an axial flux machine, which device has a punching unit for punching out recesses from a sheet metal strip at defined longitudinal positions and a rolling device for rolling up the sheet metal strip having the recesses in such a way that the recesses are located at defined angular positions in the roll of the sheet metal strip and recesses arranged at common angular positions form linear grooves running in the radial direction.The punching unit is configured to produce at least one recess by a first punching stroke and a second punching stroke such that a first boundary edge delimiting the recess along a longitudinal direction of the sheet metal strip is produced with the first punching stroke, a second boundary edge delimiting the recess along the longitudinal direction of the sheet metal strip is produced with the second punching stroke, and the two boundary edges are spaced apart from one another along the longitudinal direction of the sheet metal strip by a greater distance than at least one further recess in the sheet metal strip.
[0039] The device may further comprise a linear device with which the distance between the recesses can be adjusted and / or extensions of the size of a respective recess can be adjusted.
[0040] A corresponding control device for controlling the individual units of the device, including the linear device, can be provided. The control device can also be configured to control the rolling device in such a way that the extensions of the size of a respective recess can be adjusted.
[0041] In addition, according to the invention, an axial flux machine is provided which has a stator body manufactured according to the invention.
[0042] The above-described invention is explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, and it should be noted that the exemplary embodiments shown in the drawings are not limited to the dimensions shown.
[0043] It is shown in
[0044] Fig. 1 : a stator body of an axial flux machine in perspective view,
[0045] Fig. 2: a stator body of an axial flux machine in plan view with detail A,
[0046] Fig. 3: detail A from Figure 2 in an enlarged view,
[0047] Fig. 4: the structure of a device for carrying out the method for producing the stator body of an axial flow machine,
[0048] Fig. 5: a sheet metal strip during execution of a first punching stroke,
[0049] Fig. 6: the sheet metal strip between two punching strokes, and
[0050] Fig. 7: the sheet metal strip during a second punching stroke.
[0051] Figures 1 to 3 have already been discussed to explain the state of the art.
[0052] Figures 4 to 7 show, based on the tools used and the individual punching strokes, the sequence of the method according to the invention in order to produce a stator body as shown in Figures 1 to 3.
[0053] The features of the stator body itself mentioned below therefore refer to Figures 1 to 3.
[0054] Figure 4 shows the basic structure of the device for producing a stator body of an axial flux machine.
[0055] The device comprises a punching unit 20 with one or more punches for creating recesses in a sheet metal strip 50, a rolling device 30 for rolling up the sheet metal strip 50 provided with recesses, and a linear unit 40 for varying a distance between the rolling device 30 or the roller held thereby and the punching unit 20.
[0056] During the manufacturing process, the sheet metal strip 50 is picked up by a reel (not shown here) and fed in an extended form to the punching and stamping unit 20 along a feed direction 70. Recesses are created in the sheet metal strip 50 by means of the punching and stamping unit 20, as described with reference to Figures 5 to 7. After the sheet metal strip 50 has been processed by the punching and stamping unit 20, the sheet metal strip 50 is fed to the rolling device 30. This rolling device 30 is seated on a carriage of a linear unit 40, with which the distance between the rolling device 30 and the punching and stamping unit 20 can be adjusted. This is due to the fact that between the punching point or position of the punching and stamping unit 20 and the winding point there is a number of already punched grooves defined by the machine design, and the angular rotation of the rotation axis of the rolling device 30 is suitable for the groove located directly at the winding point.Accordingly, a change in the feed length per groove up to the punching point must be carried out by the movement of the linear unit 40 in order to adjust the distances between the recesses such that they can together form the linear grooves 17 in the stator body 10 in different radial positions, see Figure 2.
[0057] The punching processes are explained using Figures 5 to 7.
[0058] Figure 5 shows a top view of the sheet metal strip 50 during a first punching stroke. Figure 6 shows a top view of the sheet metal strip 50 between the two punching strokes, and Figure 7 shows a top view of the sheet metal strip 50 during the second punching stroke.
[0059] To prepare for the first punching stroke according to Figure 5, the rolling device 30 rotates and thereby moves the sheet metal strip 50 along the feed direction 70. Before executing the first punching stroke 81, the target size Ga of the recess 60 to be punched out along the longitudinal direction 51 of the sheet metal strip 50 is determined. Furthermore, a difference D between the target size Ga and a size Wb of an adjacent recess located at the same angular position in the radially inner adjacent turn of the roll of the sheet metal strip is determined. In addition, a theoretical distance A is determined that would result from the adjacent recess without enlarging the recess along the longitudinal direction of the sheet metal strip.
[0060] The path Sv of a feed movement of the sheet metal strip 50 is calculated from Sv = A + Wb -D / 2
[0061] A feed movement with this path Sv is carried out, and the first punching stroke 81 for producing the first boundary edge 71 is carried out at this position.
[0062] Figure 6 shows the sheet metal strip 50 with the first boundary edge 71 created.
[0063] Thereafter, a relative feed movement 85 takes place between the sheet metal strip 50 and the punching unit 20 in order to produce the second boundary edge 72, as shown in Figure 7.
[0064] The feed value of the relative feed movement 85 is the complete value of the target size Ga of the recess 60 to be produced and thus the necessary extension of the groove width in order to produce part of the radius.
[0065] This ensures that the extension of the groove width or the width of the recess 60 is symmetrical around the center line of the groove.
[0066] The second punching stroke 82 is carried out for the same recess 60. Depending on the selected target size Ga of the respective recess 60, a different size of overlap area results in a groove base.
[0067] The relative feed movement 85 can be carried out by actuating the rolling device 30 and / or the linear unit 40, as shown in Figure 4.
[0068] Adjusting the feed movement of the sheet metal strip 50 along the feed direction 70 in order to adjust the positions of the recesses 60 along the longitudinal direction 51 of the sheet metal strip 50 to the angular positions dependent on the radial positions of the recesses in the stator body can be achieved by simply actuating the rolling device 30. As a result, the webs 61 between the recesses 60 are also adjusted, and accordingly, the distances 73 are also increasingly increased during the continuous punching process.
[0069] By gradually increasing the nominal sizes Ga of the recesses 60, a radius 11 can be specifically created by step-like approach after the sheet metal strip 50 has been rolled up, as indicated in Figure 3.
[0070] Using the method described, for example, a stator body 10 with 18 slots 17 can be produced, thus having a nominal pitch of 20°. The center lines of the slots 17 are thus offset by 20°. To produce a wider slot 17, an angle of 19.5° is rotated in a first step. This is followed by the first punching stroke 81. The rolling device 30 now rotates to 20.5°. This is followed by the second punching stroke 82. Depending on the radial position of the created recess 60 in the punching body 10, the modification of the angle of rotation in degrees results in a change in the slot width in millimeters.
[0071] The method and device proposed here for producing a stator body of an axial flux machine, as well as the axial flux machine itself, provide solutions that enable the production of the stator body in a simple, cost-effective, and time-saving manner.
[0072] I Stator body
[0073] 10 stator teeth
[0074] II Radius
[0075] 12 smallest groove width
[0076] 13 largest groove width
[0077] 14 adapted winding
[0078] 15 rolls
[0079] 16 angular position
[0080] 17 grooves
[0081] 18 sheet layers
[0082] 20 punching unit
[0083] 30 rolling device
[0084] 40 linear unit
[0085] 50 metal strips
[0086] 51 Longitudinal direction
[0087] 60 recess
[0088] 61 jetty
[0089] 70 Feed direction
[0090] 71 first boundary edge
[0091] 72 second boundary edge
[0092] 73 distance
[0093] 81 first punching stroke
[0094] 82 second punching stroke
[0095] 85 Relative feed movement
[0096] Ga Size
Claims
Claims 1. A method for producing a stator body (1) of an axial flux machine, the method comprising the following steps: providing a sheet metal strip (50) and a punching unit (20), punching out sheet metal areas at defined longitudinal positions from the sheet metal strip (50) by means of the punching unit (20) such that the sheet metal strip (50) has recesses (60), and rolling up the sheet metal strip (50) having the recesses (60) such that the recesses (60) are located at defined angular positions in the roll of the sheet metal strip (50) and recesses (60) arranged at common angular positions form linear grooves (17) extending in a radial direction, wherein at least one recess (60) is produced by a first punching stroke (81) and a second punching stroke (82) such thatthat with the first punching stroke (81) a first boundary edge (71) is produced which bounds the recess (60) along a longitudinal direction (51) of the sheet metal strip (50), with the second punching stroke (82) a second boundary edge (72) is produced which bounds the recess (60) along the longitudinal direction (51) of the sheet metal strip (50), and the two boundary edges (71, 72) are at a greater distance (73) from one another along the longitudinal direction (51) of the sheet metal strip (50) than at least one further recess (60) in the sheet metal strip (50)., 2. Method according to claim 1, characterized in that the first punching stroke (81) and the second punching stroke (82) are applied to the same recess (60) and a width of the same recess (60) can be changed by changing a position of the first boundary edge (71) produced by means of the first punching stroke (81) along the longitudinal direction (51) of the sheet metal strip and / or by changing a position of the second boundary edge (72) produced by means of the second punching stroke (82) along the longitudinal direction (51) of the sheet metal strip.
3. Method according to claim 2, characterized in that the position of the first boundary edge (71) and / or the position of the second boundary edge (72) can be changed in such a way that any desired shape contours of the same recess (60) can be produced.
4. Method according to one of claims 1 to 3, characterized in that the first punching stroke (81) and the second punching stroke (82) are carried out with the same punching punch and after the execution of the first punching stroke (81) a relative feed movement (85) between the sheet metal strip (50) and the punching punch unit (20) and then the second punching stroke (82) is carried out.
5. Method according to claim 4, characterized in that the relative feed movement (83) between the sheet metal strip (50) and the punching unit (20) is carried out by a rotation of the rolled-up roll (15) of the sheet metal strip (50).
6. Method according to claim 4 or 5, characterized in that the relative feed movement (83) between the sheet metal strip (50) and the punching unit (20) is carried out by a translatory relative movement between the rolled-up roll (15) of the sheet metal strip (50) and the punching unit (20).
7. Method according to one of claims 1 to 3, characterized in that the first punching stroke (81) is carried out with a first punching punch and the second punching stroke (82) is carried out with a second punching punch and in order to produce a plurality of recesses (60) of different sizes (Ga) for each recess (60), a relative movement is carried out between the first punching punch and the second punching punch.
8. Method according to one of claims 1 to 7, characterized in that before carrying out the first punching stroke (81) it is determined which target size Ga has a recess (60) to be punched out, a difference D between the target size Ga and a size Wb of an adjacent recess (60) is determined, which is located at the same angular position in a radially inner adjacent turn of the roll (15) of the sheet metal strip (50), a theoretical distance A is determined which depends on a number of linear grooves (17) running in the radial direction and / or a current radial position of the rolled-up sheet metal strip (50) and / or a sheet thickness of the sheet metal strip (50), which would result from the adjacent recess (60) without enlarging the recess (60) along the longitudinal direction (51) of the sheet metal strip (50), a feed movement of the sheet metal strip (50) takes place with a path Sv which results from: Sv = A + Wb -D / 2, and the first punching stroke (81) takes place at the position on the sheet metal strip (51) resulting from the feed movement of the sheet metal strip (51) with the path Sv.
9. The method according to claim 8, characterized in that before carrying out the second punching stroke (82), a position of the second boundary edge (72) with respect to a position of the first boundary edge (71) is determined by adding the desired value Ga to a position measurement of the first boundary edge (71), and the second punching stroke (82) (72) takes place at the determined position of the second boundary edge (72).
10. Method according to one of claims 1 to 9, characterized in that distances (73) between adjacent recesses (60) for forming linear radially extending grooves (17) are adjusted by a translatory relative movement between the roller (15) and the punching unit (20).
11. Device for producing a stator body 1 of an axial flow machine, the device comprising: a punching unit (20) for punching out recesses (60) from a sheet metal strip (50) at defined longitudinal positions, a rolling device (30) for rolling up the sheet metal strip (50) having the recesses (60) in such a way that the recesses (60) are located at defined angular positions in the roll (15) of the sheet metal strip (50) and recesses (60) arranged at common angular positions form linear grooves (17) extending in the radial direction, wherein the punching unit (20) is configured to produce at least one recess (60) by a first punching stroke (81) and a second punching stroke (82) in such a way that a first boundary edge (71) delimiting the recess (60) along a longitudinal direction (51) of the sheet metal strip (50) is produced with the first punching stroke (81), and a second boundary edge (72) delimiting the recess (60) along the longitudinal direction (51) of the sheet metal strip (50) is produced with the second punching stroke (82). is generated and the two boundary edges (71 ,72) along the longitudinal direction (51) of the sheet metal strip (50) have a greater distance (73) from each other than at least one further recess (60) in the sheet metal strip (50)., 12. Axial flux machine having a stator body (1) manufactured according to one of claims 1 to 10.