WO2019214861A1

WO2019214861A1 - Laminated stator and method for manufacturing same

Info

Publication number: WO2019214861A1
Application number: PCT/EP2019/055226
Authority: WO
Inventors: Stefan Schoeneich
Original assignee: Magna Powertrain Bad Homburg GmbH
Priority date: 2018-05-07
Filing date: 2019-03-01
Publication date: 2019-11-14
Also published as: DE102018207041A1

Abstract

The invention relates to a stator comprising: a strip-shaped base plate (12), which on at least one side and at predetermined intervals has a plurality of wall projections (14) formed integrally with the base plate (12); a plurality of winding cores, each of which is arranged adjacent to the wall projections (14); and a plurality of windings, each of which is wound around the winding cores and the wall projections (14), an individual winding core being formed as a single piece from a metal strip folded multiple times through substantially 180° at predetermined folding points.

Description

Laminated stator and manufacturing method for such

Field of the invention

The invention relates to a laminated stator and a manufacturing method for such a stator.

State of the art

The problem with large axial or radial flux stators for intermediate rotor engines (pancake design) is that there is no suitable soft magnetic iron core around which the copper wires are wound. Either the stators are limited in size by the construction, or the construction is expensive and complicated. In most cases, the winding is done without coreless core, but this results in reduced inductance and thus lower power.

A conventional production process is disclosed, for example, in US Pat. No. 9,583,982 B2. This discloses an axial flux stator comprising a plurality of magnetically permeable members, a plurality of windings, a back iron and a jacket. The windings are connected to the magnetically permeable elements to form a plurality of magnetically permeable winding element arrays. The rear iron is mechanically connected to the magnetically permeable winding element arrangements. The jacket maintains the connection of the rear iron with the magnetically permeable winding element assemblies.

EP 2 787 610 B1 discloses a device for punching and winding a sheet metal strip into a laminated core for the production of stators and rotors, the device comprising a punching unit for punching grooves in the sheet metal strip, a winding unit for winding the stamped sheet metal strip into a laminated core wherein the punching unit is disposed in front of the winding unit, wherein driving means for changing the relative position of the winding unit with the laminated core with respect to the punching unit are provided, and a controller for controlling the punching unit, the winding unit and the drive means for adjusting the relative position of the punching unit Winding unit, wherein the device comprises one or more sensors, which detects the actual position of the groove edges on the stamped sheet metal strip and that the control of the device compares the detected actual position of the measured Nutrandes with the desired position and controls the drive means of the winding unit such that the detected position deviation is compensated for a detected deviation.

Presentation of the invention

The object of the invention is therefore to provide and provide a flux-stator, which comprises a simple and inexpensive to manufacture iron core with the lowest possible weight despite large construction for each winding. This object is achieved by a stator having the features of claim 1 and by a method having the features of claim 7.

A stator according to the invention comprises a strip-shaped base plate having, at predetermined intervals on at least one side, a plurality of wall projections integrally formed with the base plate, a plurality of winding cores respectively adjacent to the wall projections and a plurality of windings, each wound around the winding cores and the wall projections, wherein a single winding core is integrally formed of a metal strip folded at predetermined folds several times by substantially 180 °. The strip-shaped base plate can be designed to be straight for radial stators and arc, circular or ring-shaped for axial stators. By producing the winding core from a metal strip (in particular a sheet having a thickness of 0.1 mm to 0.8 mm, preferably 0.2 mm to 0.5 mm), an acceptable weight can be achieved even with large stators. chen. Furthermore, these are also inexpensive to manufacture.

Preferably, the winding cores and the adjacent wall projections are formed integrally. As a result, the assembly of the stators is greatly simplified and the iron core for the windings firmly connected to the stator.

The strip-shaped base plate may have on both sides wall projections, which are opposite to each other. In such an embodiment, it is possible to form the iron core separately from the base plate, since it can be received between the opposite wall projections. The base plate preferably has a greater wall thickness or thickness than the metal strip from which the winding cores are formed. Thereby, the stator base becomes more stable, while the winding core can be easily formed.

The metal strips, from which in each case a winding core is formed, can have at least one lateral projection at every second fold. As a result, a lateral projection is produced on the winding core at the top, with which the windings can be held on the winding core, which simplifies the assembly of the stator.

Between the windings and the winding core, an insulating braid is preferably arranged. This protects and isolates the windings from the edges of the winding core.

A stator manufacturing method of the present invention includes the steps of forming a strip-shaped base plate having at predetermined intervals on at least one side a plurality of wall projections formed integrally with the base plate, forming the coil cores by folding a metal strip a plurality of times Essentially 180 ° and the winding of windings around the winding cores. Preferably, the wall projections are formed as metal strips and are formed by folding as winding cores. The wall projections are preferably formed opposite one another on both sides of the strip-shaped base plate, the wall projections being bent upwards, and the winding core being inserted between the wall projections. Further preferably, before winding the windings around the winding cores, an insulation braid is applied around the winding core. The advantages of the respective embodiments of the methods correspond to those of the abovementioned stator embodiments.

Brief description of the figures

Figure 1a shows a plan view of a circular base plate from which a first embodiment of an axial stator of the present invention can be cut out;

FIG. 1b shows a plan view of the embodiment from FIG. 1a, in which the winding core has been formed by folding; FIG. 1 c shows a sectional view AB from FIG. 1 b on the winding core;

FIG. 1 d shows a plan view of the embodiment from FIG. 1 b, in which the winding core is bent over and anchored;

FIG. 1 e shows a sectional view A-B from FIG. 1 d on the winding core;

Figure 1f shows a plan view of the embodiment of Figure 1 d, in which the winding core is encapsulated with a resin;

FIGS. 2a to 2d show views of another embodiment of an axial stator and of the corresponding winding core, wherein the winding core has a projection on the upper side;

FIGS. 3a to 3g show views of another embodiment of a radial stator and of the corresponding winding core, wherein the winding core has a projection on the upper side;

Figures 4a to 4e are views of axial and radial stators having a winding core separated from the base plate and the wall projections;

FIGS. 5a to 5d show views of individual steps for producing an axial stator which has a winding core separated from the base plate and the wall projections; and

FIGS. 6a to 6f show views of individual steps for producing an axial stator which has a winding core separated from the base plate and the wall projections.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the term "axially" denotes a direction of an axis on which a stator is mounted (in Figure 1 in the drawing plane / out), "radially" a direction perpendicular to the axial direction (in Figure 1 from the center of the stator to the outside ) and "Circumferential" is a direction around the circumference (clockwise or counterclockwise in FIG. 1).

In Figures 1 a to 1 f, a first embodiment of a stator of the present invention is shown in various stages of manufacture. In Fig. 1 there is shown the base of a stator 10 made of sheet metal, for example by cutting (for example laser cutting) or punching. The stator comprises a base plate

12, which is formed here from a sheet metal blank for an axial stator, that is provided with a curvature, so that an annular base plate 12 is formed. In the embodiment shown in Figures 1, there is only one wall projection 14, each projecting radially toward the center of the annular base plate. Theoretically, the wall projections could also protrude outwards, but the longer they are formed, the more waste 13 would arise. The dashed area is the blend

13, which is not used for the manufacture of the stator 10. To save material, the wall projections 14 may taper towards the end, as shown in FIG. 1a. The sheet thickness of the base plate can preferably 0.5mm -2.0mm and results from the compromise between strength and elasticity of the material and eddy current losses in the finished winding core. The sheet thicknesses of the winding core are preferably less than those of the wall projections or of the base plate. This is possible with a one-piece design, as shown in FIG. 1, but the special metal sheets with different wall thickness would in turn cause higher costs. With diameters of the circular sheet metal plate up to 1200 mm, no special semi-finished products are necessary as there are production widths of electrical sheet broadband up to 1230 mm. In this respect, the preferred diameter of the circular blanks are 1200mm or less. To increase the deformability of the sheet material, a pre-annealing above the Rekristallisati- onstemperatur (700-800 ° C) can be performed.

In FIG. 1 b it is shown that the cut-free wall projections 14 are folded outward several times by a 180 ° turn-up so as to form the winding cores 16 (armature cores) at a predetermined armature height h. Such a winding core is shown in Figure 1c in a side view. In order to prevent springback of the material, the fold is preferably crimped with a predecessor stitch with a small inner radius of 180 ° and can also be compressed in a subsequent step. The resulting extension of anchor width b should be taken into account. be deducted, for example by being deducted beforehand. The possible spring-back of the folded winding core 16 should also be taken into account. The electrical sheet, which is preferably used for the production of the stators, preferably has an insulating thermoresistive layer. However, it is likewise possible to lay a film or a woven fabric of nonconductive, temperature-resistant material between the bent winding core layers during the transfer (eg a quartz or ceramic fiber braid).

The folded winding cores are then bent again by substantially 80 ° -95 °, in particular 90 °, centrally on the base plate of the stator (FIG. 1 d). The free-standing tab 18 is bent behind the base plate 12 and secured by gluing, soldering, welding, riveting or clamping. The folded sheet metal layers are then parallel to the field direction when using the stator to keep eddy currents as low as possible. In the bending radius at the edges, the eddy current losses may be slightly higher. Furthermore, an insulation braid for insulation and as edge protection, can be wound around the outer area of the anchor. The optimum magnetic properties can be set by annealing at 200-400 ° C.

After preferably the edge protection made of insulation braid or a plastic overmold has been attached to the folded winding core, the stator can be wound, for example, with copper wire 20. In Figure 1f, the winding cores are now wrapped with a copper wire and protrude axially from the base plate. With the preferred punched holes 22, the stator can be screwed to a housing or a rim. The folding and bending of the winding core from a sheet metal strip results in a very slim shape, which can be accommodated in a narrow space. Due to the size of the stator, there is also a high torque compared to conventional motors. This makes it possible to reduce the drive power, which leads to an increase in the range with the same charge capacity.

The embodiments of FIGS. 2 to 6 will be described below. Essentially, only the differences or peculiarities of the individual embodiments are discussed. FIGS. 2a to 2d show the substantially identical embodiment of an axial stator. FIG. 2 a shows a section of the sheet metal blank from which the base plate 12 and the wall projections 14 are cut out. The waste 13 is again shown in dashed lines. The wall projections 14 are likewise formed only on one side of the sheet metal blank and, as in FIG. 1, in one piece with the base plate 12. Further, the wall projections 14 are formed sufficiently long that the winding core 16 can also be formed from the respective wall projection 14 formed as a metal strip. At predetermined intervals, namely at the folds of the wall projection, lateral projections 24 are provided on the metal strip, which then after folding the winding core 16 at the top of the winding core 16 (the side facing away from the base plate) form a stop which the Wick - Keep lungs 20 on the winding core. FIG. 2b is a plan view of a winding core 16. From above, only the wider upper side of the winding core 16 can be seen. The section AB from FIG. 2b is shown in FIG. 2c. FIG. 2 d shows a side view of the winding core 16 on the side on which the tab 18 is bent under the base plate 12.

FIG. 3 a shows a sheet metal plate, in particular made of electrical steel. The embodiments of FIGS. 3a to 3g are radial flux stators. In these, the base plate is not formed annular or curved, but straight and is then bent later, which is possible due to the small wall thickness of the base plate 12. As a result of the straight strip-shaped design of the base plate 12 in the case of radial stators, a plurality of stators can be formed from a single sheet metal strip, as shown in FIG. 3 a. The waste 13 is shown in black. In the manner shown, two comb-shaped base plates 12, 12 'can be formed from an electrical steel strip via a cutting pattern without excessive waste 13. As described above, these base plates 12, 12 'likewise have integral wall projections, which are formed as metal strips and can thus also be used for the production of the winding core 16. The thus formed base plates 12, 12 'with wall projections 14, 14' and winding cores 16, 16 'can be designed as radial stator with internal or external winding cores (stator anchors). The two loose ends of the base plate 12, 12 'can be connected to each other by laser or TIG welding to ensure the circulating magnetic flux. FIGS. 3b and 3c show the base plates 12, 12 'in which the (already folded) winding cores 16, 16' are still not around the base plate 12, 12 'are bent and fixed. FIG. 3d shows a sectional view AB from FIG. 3b. In FIGS. 3e and 3f, the windings 16, 16 'are then fastened and the base plates are correspondingly shown as internal or external winding cores. FIG. 3g shows the section CD from FIG. 3e.

FIGS. 4 a to 4 e show embodiments of axial and radial stators in which the winding core 16 is produced separately from the base plate 12 and the wall projections 14. FIG. 4a shows a detail of an arrangement for an axial flux stator. In this embodiment, the base plate 12 at its inner and outer edges in each case opposite wall projections 14, 15. The wall projections are made shorter than in the base plates of FIGS. 1 to 3, since the winding cores 16 are not folded out of the wall projections, but rather from a separate metal strip. In FIGS. 4a and 4c respectively, base plates 12 with the corresponding wall projections 14, 15 are shown. The wall projections 14, 15 shown here also have the lateral projections 24, with which the windings are held on the winding cores. The wall projections 14, 15 are bent upwards by about 90 ° and the winding core, which is formed from a folded metal strip, inserted between the wall projections. Then the winding core can preferably be fastened with plastic (resin) or an adhesive or lacquer between the wall projections 14, 15 and provided with the windings. In Figures 4b and 4d, the winding cores 16 are shown within the wall projections. FIG. 4e shows a view onto the section A-B from FIG. 4b, in which the winding core 16 is arranged between the wall projections 14, 15.

FIGS. 5a-5d show an axial flux stator stator which substantially corresponds to the axial stator from FIGS. 4a and 4b. This embodiment is also suitable as a radial flux stator, but the winding core can be designed to be rectangular in such a case. The difference is in the cover portions 26, which are provided on the wall projections 14, 15. Furthermore, the winding core is also slightly conical, which will be explained in more detail below with reference to Figure 6a. On the one hand, the wall projections fix the winding cores 16 in the circumferential direction, and on the other hand, sharp edges are avoided, at which the windings could be damaged. FIG. 5a shows a plan view of the base plate 12 with the wall projections 14, 15. The wall projections 14, 15 have the cover section 26 on, covering the edges of the winding core 16 and holds this in place. In FIG. 5 b, the wall projections 14, 15 are bent upwards and the cover sections 26 are bent toward the base plate 12. In FIG. 5c, the winding cores are inserted between the wall projections and FIG. 5d shows a view of the section AB from FIG. 5c. Of course, the cover sections 26 can also be combined with an insulation fabric as edge protection.

FIGS. 6a to 6f likewise show an axial flux stator stator, which substantially corresponds to the axial stator from FIGS. 4a and 4b. Also, the embodiment shown in Figures 6 can be formed as a radial stator. The difference here is that the winding core 16 and also the wall projections 14, 15 have lateral projections 24 for holding the windings 20. FIG. 6 a shows an electrical sheet strip which is provided for the production of a winding core 16 of an axial stator. the metal strips are designed to taper to a point and the recesses (black areas in FIG. 6a) are cut out for the lateral protrusions without the protrusions 24 being pointed, the pointed or tapered metal strips for the winding cores 16 are simply cut out with straight edges (the black ver - cut surfaces in Figure 6 fall away). As mentioned above, radial stators can be used to cut out rectangular metal strips.

To produce a stator according to the invention, therefore, depending on the desired type of stator (radial or axial stator), a corresponding base plate 12, 12 'with at least one wall projection 14, 14' is cut out of a metal sheet. The cutting can be performed by known methods. Then, the metal strip of the winding core 16 is also cut out of a metal sheet, if it has not already been formed together with the base plate 12, 12 'and the respective wall projections 14, 14'. The metal strip is then folded by in each case substantially 180 °, so that a laminated core is formed, which forms the winding core 16. In each case, an insulation braid can be arranged between the layers, which is placed in each case before bending over. Depending on the embodiment, either the wall projection 14, 14 'upwards and the winding core on the base plate 12, 12' and the tab then under the base plate 12, 12 'bent, or the wall projections 14 and 15 bent upward and the separate winding core 16 inserted between the wall projections 14, 15. The winding cores are preferably connected to the base plate 12 and / or the wall projections 14, for example by gluing, and are then preferably wrapped with an edge protection 19 such as an insulation braid or encapsulated with a resin in order to avoid damage to the winding wire by sharp edges. Instead or in addition, covering sections can be bent around the winding core 16 in the direction of the base plate, if these are present. Then the winding core with a good conductive wire, for example. Of copper, wrapped and possibly cast. This process can still be refined by the heat treatment steps mentioned above.

Bezuaszeichenliste

10 stators

12, 12 'base plate

13 waste

14, 14 'wall projection

15 Opposite wall projection

16, 16 'winding core

18 tab

19 edge protection

20 windings

22 mounting hole

24 Lateral projection

26 cover section

Claims

claims

A stator (10) comprising: a strip-shaped base plate (12) having at predetermined intervals on at least one side thereof a plurality of wall projections (14) integrally formed with the base plate (12); a plurality of winding cores (16) each disposed adjacent to the wall projections (14); and a plurality of windings (20) wound around the winding cores (16) and the wall projections (14), respectively; characterized in that a single winding core (14) is formed in one piece from a metal strip folded at predetermined folds several times by substantially 180 °.

Second stator (10) according to claim 1, wherein the winding cores (16) and the adjacent wall projections (14) are integrally formed.

3. stator (10) according to claim 1 or 2, wherein the strip-shaped base plate (12) on both sides wall projections (14, 15) which are opposite to each other.

4. stator (10) according to any one of the preceding claims, wherein the base plate (12) has a greater sheet thickness, than the metal strip from which the winding cores (16) are formed.

5. stator (10) according to any one of the preceding claims, wherein the folded metal strip, each of which a winding core (16) is formed on each second Faltstel- le has at least one lateral projection (24).

6. stator (10) according to any one of the preceding claims, in which between the windings (20) and the winding core (24) an insulation braid is arranged.

7. A method for producing a stator (10), in particular according to one of the preceding claims, comprising the steps:

- forming a strip-shaped base plate (12) having at predetermined intervals on at least one side a plurality of integrally formed with the base plate wall projections (14, 14 '15);

- Forming the winding cores (16) by folding several times a metal strip by substantially 180 °; and

- winding windings around the winding cores (16).

8. The method of claim 7, wherein the wall projections (14) are formed as metal strips and are formed by folding as winding cores (16).

9. The method of claim 7, wherein the wall projections (14, 15) on both sides of the strip-shaped base plate (12) are formed opposite to each other, wherein the wall projections are bent upward, the winding core is inserted between the Wandvor- jumps.

10. The method according to any one of claims 7 to 9, wherein prior to winding the windings (20) around the winding cores (16) further an insulation braid around the winding cores (16) is applied.