Stator of an electric rotating machine, electric rotating machine, and geared motor unit

Abstract

The invention relates to a stator of an electric rotating machine, an electric rotating machine equipped therewith and to a geared motor unit having the electric rotating machine. The stator (20) of the electric rotating machine (1) has a plurality of stator teeth (22), of which at least one stator tooth (22) comprises a laminated core (30) and on at least one side of the laminated core (30) facing a rotor (10) of an electric rotating machine (1) comprising the stator (20), at least one pole shoe (40) is arranged which delimits an air gap (21) between the rotor (10) and the stator tooth (22) and is formed at least in regions from a soft-magnetic composite material, wherein the pole shoe (40) is bounded between its side facing the air gap (21) and its side facing the laminated core (30) on at least one side (50) bounding the pole shoe (40) along the circumferential direction (71) by an obliquely extending surface (60) and the cross-section of the pole shoe (40) is larger on the side facing the air gap (21) than on the side facing the laminated core (30). Using the rotor proposed here and the electric rotating machine equipped therewith, devices can be provided which, in a simple constructional design, guarantee long-lasting operation of the electric rotating machine with high efficiency.

Description

[0001] Stator of an electric rotating machine, electric rotating machine and geared motor unit

[0002] The invention relates to a stator of an electric rotary machine, an electric rotary machine equipped therewith and a geared motor unit with the electric rotary machine.

[0003] Electric drive motors are known from the state of the art in many industrial applications, and are also increasingly being used in the automotive industry. Such a motor comprises a stator and a rotor that rotates relative to it. The rotor typically includes a rotor shaft, balancing plates, rotor cores, and magnets.

[0004] Particularly for applications in electrically powered motor vehicles, the requirement is to achieve the required power within the available installation space. Accordingly, the electric rotating machine must be designed as a very compact axially radial flux machine or as an axial flux machine. The required installation space for the power electronics associated with the respective electric rotating machine must also be taken into account.

[0005] To reduce iron losses in the stator, high-quality, non-grain-oriented electrical steel sheets with very thin sheet thicknesses are typically used. If the machine topology allows, grain-oriented electrical steel sheets can also be used, which typically further minimize losses.

[0006] Such electrical steel sheets are frequently used in stator-yokeless axial flux machines. However, here the guidance of the magnetic flux from the air gap to the stator tooth can also cause losses. In electrical rotating machines with non-grain-oriented electrical steel sheets, funnel-shaped tooth geometries made of the same material as the electrical steel sheets are sometimes used. When grain-oriented electrical steel sheets are used, pole shoes made of a soft magnetic composite material are used in some places and arranged on the laminated core. The poorer flux guidance properties of the soft magnetic composite material are accepted because the total losses resulting from a combination of grain-oriented electrical steel sheets and soft magnetic composite material are lower than when the laminated core is constructed from non-grain-oriented electrical steel sheets.

[0007] DE 10 2020 101 149 A1 discloses an axial flux machine, preferably for a drive train of a purely electrically or hybrid-powered motor vehicle, comprising an annular stator and two rotor elements mounted rotatably relative to the stator about a common axis of rotation. A first rotor element is arranged axially along the axis of rotation next to a first axial end face of the stator, and a second rotor element is arranged axially next to a second axial end face of the stator. The stator comprises a plurality of stator cores distributed in a circumferential direction of a circular line extending around the axis of rotation. The stator cores comprise pole shoes arranged along the circumferential direction next to the laminated core.

[0008] DE 10 2015 223 766 A1 teaches an electrical machine in the form of an axial flux motor, with a rotor mounted so as to be rotatable about a machine axis, and with a stator which has a sintered support structure and an insert connected thereto, which at least partially forms a pole shoe, and which comprises a laminated core.

[0009] Based on this, the present invention is based on the object of providing a stator and an electric rotary machine equipped therewith, which ensure long-lasting operation with high efficiency in a simple structural design.

[0010] This object is achieved by the stator according to the invention as defined in claim 1 and by the electric rotary machine as defined in claim 8. Advantageous embodiments of the stator are specified in subclaims 2-7. In addition, a geared motor unit is provided as defined in claim 9. The features of the claims can be combined in any technically reasonable manner, whereby the explanations from the following description and features from the figures, which comprise supplementary embodiments of the invention, can also be considered.

[0011] The terms “axial”, “radial” and “in the circumferential direction” refer in the following to the axis of rotation of an electrical rotating machine equipped with the stator.

[0012] The invention relates to a stator of an electrical rotary machine, comprising a plurality of stator teeth, of which at least one stator tooth comprises a laminated core, and on at least one side of the laminated core facing a rotor of an electrical rotary machine comprising the stator, at least one pole shoe is arranged which delimits the air gap between the rotor and the stator tooth and is formed at least partially from a soft magnetic composite material. Between its side facing the air gap and its side facing the laminated core, the pole shoe is delimited by an inclined surface on at least one side delimiting the pole shoe along the circumferential direction, wherein the cross-section of the pole shoe is larger on the side facing the air gap than on the side facing the laminated core.

[0013] The sloping surface may, if necessary, have further form elements to a minor extent, such as unevenness, so that it is essentially a sloping surface.

[0014] The cross-section mentioned is a section that runs parallel to the axis of rotation of a rotor of an electrical rotating machine comprising the stator and perpendicular to the planes of the laminations of the laminated core when these are aligned essentially radially with respect to the axis of rotation. Insofar as the stator is designed for a stator yoke-less arrangement of rotors of an axial flux machine - i.e. for a so-called H-arrangement - the stator tooth has two axially opposite sides. Each stator tooth is formed by a laminated core and is separated from an adjacent stator tooth on the circumference by slots and windings placed in the slots. The pole shoe extends from the laminated core in the direction of the air gap or the position of the rotor. In one embodiment, the pole shoe is thus located exclusively between the air gap and the laminated core, and not along the circumferential direction next to the laminated core.

[0015] The pole piece is a component made of a material with high permeability and serves to allow the magnetic field lines to emerge and distribute them in a defined shape.

[0016] According to the invention, the pole shoe geometry is optimized so that in addition to optimal flux guidance, shielding of harmonic fields is also achieved.

[0017] In one embodiment of the stator, the stator is the stator of an axial flux machine, so that the pole shoe is arranged on an axial side of the laminated core. The pole shoe is delimited between its side facing the air gap and its side facing the laminated core on at least one side radially delimiting the stator tooth by an inclined surface, wherein the cross-section of the pole shoe is larger on the side facing the air gap than on the side facing the laminated core.

[0018] The cross-section referred to here runs in a section parallel to the axis of rotation of a rotor of an electrical rotary machine comprising the stator and parallel to the planes of the laminations of the laminated core when these are aligned substantially radially with respect to the axis of rotation.

[0019] The laminations of the laminated core can be grain-oriented electrical laminations. This means that the electrical laminations are made of a grain-oriented iron material. Alternatively, the laminations of the laminated core can be non-grain-oriented electrical laminations. This embodiment enables increased efficiency in machine topologies that do not permit the use of grain-oriented electrical laminations.

[0020] An advantageous embodiment of the stator provides that the inclined surface extends up to a maximum of 60% of the pole shoe height defined between the laminated core and the air gap. Accordingly, this embodiment of the stator provides that, in addition to its respective inclined surface, the pole shoe also has a further boundary surface that adjoins the inclined surface and delimits the pole shoe along the circumferential direction or radially. Furthermore, the inclined surface can extend up to at least 40% of the pole shoe height defined between the laminated core and the air gap.

[0021] Furthermore, the stator can comprise at least one winding per stator tooth, which wraps around the respective stator tooth, wherein the pole piece forms at least one projection along the circumferential direction, which axially overlaps the winding in some areas and extends along the circumferential direction to at least 50% of the maximum distance of the winding from the laminated core. This means that the projection extends toward the adjacent stator tooth.

[0022] In addition, the stator can comprise at least one winding per stator tooth, which wraps around the respective stator tooth. The pole piece forms at least one projection along the circumferential direction, which axially overlaps the winding in some areas and extends along the circumferential direction up to 100% of the maximum distance of the winding from the laminated core. The side of the projection facing the laminated core has an inclined surface on at least one side.

[0023] The inclined surface can essentially adjoin the laminated core. Minor deviations from this design, resulting in a step between the inclined surface and the outer surface of the laminated core, are insignificant in this embodiment. For example, with pole pieces located on both sides of the laminated core, the inner boundary edges of the inclined surfaces relative to the laminated core can have a distance from each other that corresponds to 90% to 110% of the width of the laminated core.

[0024] The stator according to the invention can be a stator of an axial flux machine, so that the pole piece is arranged on an axial side of the laminated core. In this embodiment, it is accordingly provided that the pole piece has an inclined surface at least on one radially extending edge, the plane of which, in addition to the general radial extent, is oriented with a directional component in the circumferential direction and in the axial direction, and is formed on the side facing the winding.

[0025] Furthermore, this pole piece can also have such an inclined surface on a radially limiting side.

[0026] In an alternative embodiment, the stator is a stator of a radial flux machine, so that the pole piece is arranged on a radial side of the laminated core.

[0027] A further aspect of the present invention is an electric rotary machine comprising a stator according to the present invention and a rotor arranged opposite the stator at the air gap. This electric rotary machine can be an axial flux machine or a radial flux machine. In the case of an axial flux machine, it can have a stator yoke-less design—a so-called H-arrangement—in which the stator is arranged axially centrally and a rotor is arranged axially on each side of the stator for rotation.

[0028] By combining the inventive pole shoe geometry with the material-based subdivision of the stator tooth into a laminated core and pole shoe, the efficiency of the electric rotating machine equipped with it can be increased. The electrical sheet reduces power losses and magnetic resistance, but only allows for one-dimensional flux flow. The soft magnetic composite material enables three-dimensional flux flow with low eddy current losses, which are particularly prevalent in fields with harmonics, and also allows for more complex geometries in production.

[0029] Accordingly, the inventive design of the pole piece reduces unwanted stray fluxes and, through its shielding effect, eliminates the main problem of the conventional two-part stator made of soft magnetic composite material and electrical steel sheets.

[0030] The inclined surface also provides a surface area which, in the case of direct groove cooling, enables additional convection at a thermally critical point.

[0031] The invention also provides a geared motor unit which has at least one electric rotary machine according to the invention and at least one gearbox whose gearbox input shaft is or can be coupled to a rotor shaft of the electric rotary machine.

[0032] The invention described above will be explained in detail below against the relevant technical background with reference to the accompanying drawings, which show embodiments. The invention is in no way limited by the purely schematic drawings, whereby it should be noted that the embodiments shown in the drawings are not limited to the dimensions shown. It is shown in

[0033] Fig. 1 : an electric rotary machine according to the invention in a partial sectional view from the side, and

[0034] Fig. 2: the electric rotary machine according to the invention in a further partial sectional view.

[0035] Figures 1 and 2 show an electric rotary machine 1 designed according to the invention in different views, wherein Figure 1 shows a partial section of the electric rotary machine 1 above the rotation axis, and Figure 2 shows a partial section of the electric rotary machine 1 in a section that runs perpendicular to the section line of Figure 1. The electric rotary machine 1 and its stator 20 are explained below with reference to both Figures 1 and 2.

[0036] The electric rotary machine 1 shown here forms a stator yoke-less, or so-called H-arrangement, of the two rotors 10 arranged axially on either side of the stator 20. The magnets 11 of the two rotors 10 are each arranged opposite the stator 20, so that a respective air gap 21 is formed between a respective magnet 11 and the stator 20 or its respective pole piece 40.

[0037] Only one stator tooth 22 of the stator 20 is depicted in Figures 1 and 2. The stator tooth 22 comprises a laminated core 30, which comprises several laminations 33 made of grain-oriented or non-grain-oriented iron material.

[0038] Figure 2 shows that the individual laminations 33 are essentially radially aligned. The laminated core 30 is wrapped by at least one winding 42.

[0039] A pole shoe 40 made of a soft magnetic composite material is fixed to each of the two axial sides 31 of the laminated core 30.

[0040] A respective pole shoe 40 has an obliquely extending surface 60 on its side 51 radially delimiting the stator tooth, as shown in Figure 1, and on its side 50 delimiting the stator tooth along the circumferential direction 71, as shown in Figure 2.

[0041] This inclined surface 60 causes a projection 70, which exists along the circumferential direction 71 and radially and is formed by the respective pole shoe 40, to have a smaller cross-section on its outside than in the area of ​​the fixation on the laminated core 30. This allows the magnetic flux to be guided in an optimal manner into the winding 42 and into the laminated core 30, while at the same time shielding fields containing harmonics.

[0042] However, in the embodiment shown here, the obliquely extending surface 60 does not extend to the axial outer side of the respective pole shoe 40, but ends at a certain distance in front of the axial outer side, so that the pole shoe 40 has a respective further boundary surface 61 on its radial outer side or on its radial inner side, as well as on its circumferentially limiting side.

[0043] It is intended that the inclined surface 60 extends up to a maximum of 60% of the height 41 of the pole piece 40 defined between the laminated core 30 and the air gap 21.

[0044] As can be seen in particular from Figure 2, the projection 70 of the pole piece 40, delimited by the inclined surface 60, extends approximately far enough along the circumferential direction 71 that the adjacently arranged winding 42 is almost completely axially covered. In other words, this projection 70 extends approximately as far as the distance 43 of the winding 42 from the laminated core 30.

[0045] Furthermore, Figure 2 shows that the inclined surfaces 60, which are arranged on the sides 50 delimiting the stator tooth 22 along the circumferential direction 71, extend until they meet the laminated core 30. In other words, these two inclined surfaces 60, which are opposite one another along the circumferential direction 71, are separated from one another by a distance corresponding to the width 32 of the laminated core 30.

[0046] The inventive design of the stator makes it possible to reduce magnetically induced power losses by approximately 10%.

[0047] The stator proposed here and the electric rotary machine equipped with it provide devices which, in a simple structural design, ensure long-lasting operation of the electric rotary machine with high efficiency.

[0048] List of reference symbols

[0049] 1 electric rotary machine

[0050] 2 rotation axis

[0051] 10 Rotor

[0052] 11 Magnet

[0053] 20 Stator

[0054] 21 Air gap

[0055] 22 stator tooth

[0056] 30 sheet packages

[0057] 31 axial side of the laminated core

[0058] 32 Width of the laminated core

[0059] 33 sheet metal

[0060] 40 Pole piece

[0061] 41 Height of the pole piece

[0062] 42 winding

[0063] 43 Distance of the winding from the laminated core

[0064] 50 side limiting the stator tooth along the circumferential direction

[0065] 51 side radially limiting the stator tooth

[0066] 60 sloping surface

[0067] 61 additional boundary area

[0068] 70 lead

[0069] 71 Circumferential direction

Claims

Patent claims 1. Stator (20) of an electric rotary machine (1), comprising several stator teeth (22), at least one of which comprises a laminated core (30), and at least one pole shoe (40) is arranged on at least one side of the laminated core (30) facing a rotor (10) of an electric rotary machine (1) comprising the stator (20), the pole shoe (40) defining an air gap (21) between the rotor (10) and the stator tooth (22), the pole shoe being formed at least partially from a soft magnetic composite material, wherein the pole shoe (40) is bounded on at least one side (50) defining the pole shoe (40) along the circumferential direction (71) by an inclined surface (60) between its side facing the air gap (21) and its side facing the laminated core (30), and the cross-section of the pole shoe (40) on the side facing the air gap (21) is larger than on the side facing the laminated core (30) facing side.

2. Stator according to claim 1, characterized in that the stator (20) is the stator (20) of an axial flux machine, such that the pole shoe (40) is arranged on an axial side of the laminated core (30), wherein the pole shoe (40) is bounded between its side facing the air gap (21) and its side facing the laminated core (30) on at least one side (51) radially limiting the stator tooth (22) by an inclined surface (60), wherein the cross-section of the pole shoe (40) is larger on the side facing the air gap (21) than on the side facing the laminated core (30).

3. Stator according to one of the preceding claims, characterized in that the laminations (33) of the laminated core (30) are grain-oriented electrical steel sheets.

4. Stator according to one of the preceding claims, characterized in that the inclined surface (60) extends up to a maximum of 60% of the area between The sheet metal package (30) and air gap (21) extend to the defined height (41) of the pole shoe (40).

5. Stator according to one of the preceding claims, characterized in that the stator (20) comprises at least one winding (42) for each stator tooth (22) which wraps around the respective stator tooth (22), wherein the pole shoe (40) forms at least one projection (70) along the circumferential direction (71) which axially covers the winding (42) in certain areas and extends along the circumferential direction (71) to at least 50% of the maximum distance (43) of the winding (42) from the laminated core (30).

6. Stator according to one of the preceding claims, characterized in that the stator (20) comprises at least one winding (42) for each stator tooth (22) which wraps around the respective stator tooth (22), wherein the pole shoe (40) forms at least one projection (70) along the circumferential direction (71) which axially covers the winding (42) in certain areas and extends along the circumferential direction (71) up to 90% of the maximum distance (43) of the winding (42) from the laminated core (30).

7. Stator according to one of the preceding claims, characterized in that the inclined surface (60) substantially abuts the laminated core (30).

8. Electric rotary machine comprising a stator (20) according to one of claims 1 to 7 and a rotor (10) arranged at the air gap (21) opposite the stator (20).

9. Geared motor unit comprising at least one electric rotary machine (1 ) according to claim 8, and at least one gearbox whose gearbox input shaft is coupled or can be coupled to a rotor shaft of the electric rotary machine (1 ).

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