Electric drive with toroidal coil carrier

Abstract

The electric drive comprises a stator (2) and a rotor (1) and a number of coils of a winding (3). The stator (2) has a toroidal coil carrier (21), the cross-sectional area of ​​which has the shape of an ellipse, in particular a circle. The coils of the winding (3) are wound around a section (215) of the toroidal coil carrier (21).

Description

[Technical field]

[0001] The present invention relates to an electric drive having a stator and a rotor. The proposal includes in particular the case of radial flux machines having only one stator and only one rotor, as well as the case of axial flux machines having in particular two stators and one rotor. Furthermore, there are a large number of coils. [Background technology]

[0002] An electric drive is an electric machine that converts electrical power into mechanical power. Current-carrying conductor coils generate magnetic fields whose mutual attraction and repulsion are converted into motion. The so-called inner rotor has a fixed outer part and a rotating inner part. These parts are called the stator and the rotor.

[0003] Electric motors are used in industries such as, for example, the packaging and food industries, robotics, medical technology and medical aids, or even in mobility, such as, for example, electric bicycles, small vehicles, small aircraft.

[0004] Conventionally, the length of the side is l 1 and l 2 A rectangular teeth structure is used for the stator shape, and in particular for the teeth coil winding. In this case, usually, 1 is 2 is much larger than the side length l 1 is considered as a torque forming winding, with side length l 2 is considered an undesirable winding head. On the one hand, the change in magnetic flux and therefore its amplitude must be maximized, and on the other hand, the current heat losses in the winding must be minimized. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to provide an electric drive having a physically and mathematically optimized winding geometry. [Means for solving the problem]

[0006] This object is solved by the subject matter of the independent claims. Thus, an electric drive comprises a stator and a rotor. The stator is fixed and the rotor moves. The rotor rotates a drive shaft. The electric drive comprises a number of windings of a winding wire wound into a coil. In particular, the winding wire usually consists of a copper wire, in particular an enamelled copper wire.

[0007] The electric drive comprises a toroidal coil carrier, where the coil of winding wire is wound around a section of the toroidal coil carrier and is supported by the toroidal coil carrier. The term toroidal coil carrier or toroidal body describes a rotating body with a hole in the middle. The axis of rotation passes through the hole and does not cross the rotating body. Any cross-sectional area can be rotated, for example a square. If the cross-sectional area is rotated in the form of a circle, the toroidal body is called a "torus". The cross-sectional area of ​​the toroidal coil carrier has the shape of an ellipse, in particular the shape of a circle.

[0008] Applying coils around a "section" of a toroidal coil carrier means that these coils are only present partially, rather than along the entirety of the rotating region.

[0009] A circle as a cross-sectional area has the largest surface area with the smallest possible perimeter of any 2D geometric shape. This minimizes the length of the surrounding wire. As a result, the current heat loss in the winding wire wound in a circular shape around the toroidal coil carrier is also minimized, since the amount of current heat loss is a function of the length of the winding wire. Alternatively, if the cross-sectional area is designed as an ellipse instead of a circle, the shape, although not optimal, is still better than the rectangular teeth configuration of conventional electric drives.

[0010] Advantageously, the stator has a lamination structure with a number of laminations. The coils are wound between the laminations around the sections of the toroidal coil carrier, respectively. In particular, the toroidal coil carrier and the lamination structure are designed together as a stator. In the case of larger stator shapes, the stator can be assembled and joined from individual segments or from several sections.

[0011] The addition of lamination structures to the toroidal coil carrier allows the use of conventional rotor structures, which can be either axial or radial flux rotors. Without lamination structures, such electric drives could only be produced with enormous manufacturing effort.

[0012] In particular, the laminate extends over a greater length in the direction of the rotation axis of the toroidal coil carrier than the toroidal coil carrier, which allows for a larger stator capable of accommodating the main magnetic flux from the rotor and allows the use of conventional rotor structures.

[0013] In particular, when designed as a radial flux machine, the lamella extends in the direction of the rotation axis of the toroidal coil carrier over at least twice the length, in particular over at least three times the length, of the toroidal coil carrier.

[0014] Advantageously, the laminate structure is designed as a toroidal body, the laminate corresponding to a section of the toroidal body, the sections for the individual coil formers of the winding being arranged between these sections of the laminate.

[0015] In particular, the axis of rotation of the toroidal coil carrier is the same as the axis of rotation of the toroidal body of the laminated structure.

[0016] Advantageously, the toroidal body has a cross-sectional area at least three times as large as the cross-sectional area of ​​the toroidal coil former, in particular at least five times as large, resulting in a stator with a large air gap area to accommodate the main magnetic flux from the rotor.

[0017] Advantageously, the maximum radial extent of the toroidal coil carrier starting from the axis of rotation is the same size as the maximum radial extent of the toroidal body of the laminated structure starting from the axis of rotation. In other words, the toroidal coil carrier and the laminated structure, which together in particular form the stator, are located in the same plane with each other on their respective outsides. This design is provided in particular for an inner rotor.

[0018] Alternatively, the minimum radial extent of the toroidal coil carrier starting from the axis of rotation can be the same size as the minimum radial extent of the toroidal body of the laminated structure starting from the axis of rotation. This design is particularly suitable for the outer rotor.

[0019] Such a geometrical configuration of the stator has the advantage that the coils wound from the winding wire partially protrude from the laminated structure and are therefore easily accessible for cooling.

[0020] In other words, the coils of the winding extend to a region radially further away from the axis of rotation than the radially outermost region of the laminated structure. This configuration is provided particularly for inner rotors.

[0021] Alternatively, the windings may extend to a region that is a shorter radial distance from the axis of rotation than the radially innermost region of the laminated structure.

[0022] In particular, the electric drive comprises only one stator and only one rotor in the radial flux machine version and only two stators and only one rotor in the axial flux machine version.

[0023] Advantageously, the toroidal coil carrier has a maximum annular ring diameter of at most 200 mm, in particular at most 100 mm and / or at least 60 mm, in particular at least 80 mm. If the toroidal coil carrier has a circular cross-sectional shape, the diameter of this circle is in particular more than 5 mm, in particular more than 10 mm and / or less than 20 mm, in particular less than 15 mm.

[0024] In particular, the stator surrounds the rotor, i.e. the rotor is located within the core of the stator. This is the so-called internal rotor. Alternatively, the rotor surrounds the stator. This is known as an external rotor. The rotor is preferably a radial flux rotor.

[0025] If the cross-sectional area of ​​the toroidal coil carrier has the shape of an ellipse, the major axis of this ellipse is at most 1.3 times, in particular at most 1.2 times, longer than the minor axis of this ellipse.

[0026] The stator is constructed from 3D flux conducting materials with means to reduce eddy currents. Examples include soft magnetic powder composites (SMC), ferrite, or nanocrystalline materials.

[0027] Further embodiments, advantages and applications of the invention are set forth in the dependent claims and in the following description with reference to the drawings. [Brief description of the drawings]

[0028] [Figure 1a] FIG. 2 shows a first electric drive in a radial configuration as an inner rotor. [Figure 1b] FIG. 2 shows the stator of the first electric drive without the coils of the stator winding. [Figure 1c] FIG. 2 is a top view of the stator without the coils of the stator windings. [Figure 1d] FIG. 1c is a cross-sectional view of the stator taken along the section line shown in FIG. [Figure 1e]FIG. 2 is a side view of the stator without the coils of the stator winding. [Figure 1f] 1c is a cross-sectional view of the stator taken along the section line shown in FIG. 1e, where the shaded areas represent the coils of the stator winding. [Figure 2a] FIG. 2 shows a second electric drive in radial configuration as an external rotor. [Figure 2b] FIG. 13 shows the stator of the second electric drive without the coils of the stator winding. [Figure 2c] FIG. 2 is a top view of the stator without the coils of the stator windings. [Figure 2d] FIG. 2c is a cross-sectional view of the stator taken along the section line shown in FIG. 2c, without the coils of the stator winding. [Figure 2e] FIG. 2 is a side view of the stator without the coils of the stator winding. [Figure 2f] 2c is a cross-sectional view of the stator taken along the section line shown in FIG 2e, with the shaded areas representing the coils of the stator windings. [Figure 3a] FIG. 13 shows a third electric drive in an axial configuration. [Figure 3b] FIG. 13 shows a stator portion of a third electric drive device. [Figure 3c] FIG. 2 is a view of the stator portion as viewed from a flat surface. [Figure 3d] FIG. [Figure 4] FIG. 13 illustrates the cross-sectional area of ​​a toroidal coil carrier in an alternative embodiment having an elliptical shape. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Figure 1a shows a first electric drive, which comprises a rotor 1 and a stator 2. Figures 1b to 1f show only the stator 2, in which the coils of the winding 3 are shown as shaded areas.

[0030] The stator 2 comprises a toroidal coil carrier 21. The toroidal coil carrier 21 is a rotating body which rotates a cross-sectional area 211. In the present embodiment, the cross-sectional area 211 is a circle with an exemplary radius of 6 mm. A coil 3 is wound around the toroidal coil carrier 21. As already mentioned, in FIG. 1f this coil 3 is indicated by a shaded area.

[0031] The only part around which the coils of the windings of the stator 2 are wound is called the toroidal coil carrier 21. In this embodiment, this part is a torus, the inside of which is defined by the dashed line 212 and the outside of which is defined by the circular solid line 213 in Fig. 1f.

[0032] The toroidal coil carrier 21 is supplemented with a laminated structure 22. The stator 2 thus comprises the toroidal coil carrier 21 and the laminated structure 22. The stator 2 is designed in one piece, but it can also be made up of joined sub-segments.

[0033] The sections 215 of the toroidal coil carrier 21 around which the coil 3 is wound are exposed between the laminations 221. In other words, the coil 3 does not surround the toroidal coil carrier 21 along the entire circular ring, but only the sections 215 between the laminations 221. In this embodiment, the stator 2 or lamination structure 22 comprises a total of 12 laminations 221 and 12 sections 215 of the toroidal coil carrier 21 between these laminations 221.

[0034] In the direction of the rotation axis 214, the laminate 221 extends over a length L1 which is longer than the length L2 of the toroidal coil carrier 21, such as for example 40 mm. This length L1 is approximately three times the length L2.

[0035] In this embodiment, the laminar structure 22 is also a toroidal body. This is because the laminar structure 22 is a body of revolution and the cross-sectional area 222, which is shown hatched in FIG. 1d, rotates about the axis of revolution 214. The axis of revolution of the toroidal coil carrier 21 and the axis of revolution of the laminar structure 22 are identical. However, the laminar structure 22 is not continuous along the circular ring, but only partially. These sections of the laminar structure 22 are the laminar bodies 221. The toroidal body of the laminar structure 22 is interrupted between the laminar bodies, which forms intermediate spaces for the coils of the winding 3.

[0036] The cross-sectional area 222 of the toroidal body of the laminate structure 22 is approximately 6 to 7 times larger than the cross-sectional area 211 of the toroidal coil carrier 21. As a result, the stator 2 has a large air gap area to accommodate the main magnetic flux from the rotor.

[0037] The maximum radial extent R1 of the toroidal coil carrier 21 is exactly the same size as the maximum radial extent R2 of the laminated structure 22. This has the positive effect that the portion 31 of the coil 3 is exposed outside the stator 2 and is easily accessible at this location for cooling 4. In other words, the coils of the winding 3 extend to an area located further radially outward from the axis of rotation 214 than the radially outermost area of ​​the laminated structure 22. The radii R1 and R2 in this exemplary embodiment are 40 mm and correspond to the maximum annular diameter of the toroidal bodies of the toroidal coil carrier 21 and the laminated structure 22.

[0038] Figure 2a shows a second electric drive, which also comprises only one rotor 1 and only one stator 2. Figures 2b to 2f show only the stator 2, in which the windings 3 are shown in the shaded area. The reference numbers are used in the same way as in Figures 1a to 1f. The rotor 1 is the so-called "outer rotor" since it surrounds the stator 2.

[0039] This stator 2 is designed according to the same principle as the stator 2 of the first electric drive. It also comprises a toroidal coil carrier 21 with a circular cross-sectional area 211, around which the coils constituting the winding are partially mounted.

[0040] One difference with respect to the first electric drive is that the minimum radial extent R3 of the toroidal coil carrier 21 is exactly the same size as the minimum radial extent R3 of the laminated structure 22. This has the positive effect that a portion 31 of the winding 3 is exposed inside the stator 2 and is easily accessible at this location for cooling 4. In other words, the winding 3 extends to a region located further radially inward from the axis of rotation 214 than the radially innermost region of the fin structure 22.

[0041] Figures 3a-3d show an inner rotor in an axial configuration. It comprises a rotor 1 and a stator 2 with two stator parts 2a and 2b. Both stator parts 2a and 2b are constructed according to the same principle as the stators of the first and second electric drives. One difference is that the toroidal coil carrier 21 is located in the same plane with the outermost part of the lamination structure 22 in the axial direction, rather than in the radial direction. The toroidal coil carrier 21 and the lamination structure 22 are located in the same plane at the position of the dashed line 23.

[0042] 4 shows an ellipse 5. In a particular embodiment, the cross-sectional area 211 of the toroidal coil carrier 21 may have the shape of such an ellipse 5. For example, the ellipse has a major axis gA that is 1.2 times as long as the minor axis kA.

[0043] If the cross-sectional area of ​​the toroidal coil carrier has an elliptical shape, the major axis of this ellipse is in particular at most 1.3 times, in particular at most 1.2 times, longer than the minor axis of the ellipse.

[0044] Although preferred embodiments of the present invention are described in this application, it should be expressly pointed out that the present invention is not limited thereto and may be embodied in other ways within the scope of the appended claims. [Explanation of symbols]

[0045] 1 rotor 2 Stator 2a Stator part 2b Stator part 3 Windings, Coil 4 Cooling 5. Ellipse 21 Toroidal coil carrier 22 Thin layer structure, fin structure 23 Dashed Line 31 parts 211 Cross-sectional area 212 dashed line 213 Circular solid line 214 Rotational Axis Section 215 221 Thin layer body 222 Cross-sectional area

Claims

1. 1. An electric drive comprising a stator (2) and a rotor (1) and a plurality of coils of a winding (3), characterized in that the stator (2) comprises a toroidal coil carrier (21) having an axis of rotation (214), the toroidal coil carrier (21) having an elliptical, in particular circular, cross-sectional area (21), and the coils of the winding (3) are wound around a section (215) of the toroidal coil carrier (21).

2. 2. The electric drive according to claim 1, wherein the stator (2) has a lamination structure (22) with a plurality of laminations (221), the coils of the winding being applied between the laminations (221) around the section (215) of the toroidal coil carrier (21).

3. 3. An electric drive according to claim 2, wherein the laminate (221) extends over a length greater than the toroidal coil carrier (21) in the direction of the axis of rotation (214) of the toroidal coil carrier (21).

4. 4. An electric drive according to claim 3, wherein the lamination (221) extends over at least twice the length, in particular at least three times the length, of the toroidal coil carrier (21) in the direction of the rotation axis (214) of the toroidal coil carrier (21).

5. 5. An electric drive according to claim 2, wherein the laminated structure (22) is configured as a toroidal body, the laminated bodies (221) being sections of the toroidal body, intermediate spaces for the coils of the winding (3) being present between the sections.

6. 6. An electric drive according to claim 5, wherein the axis of rotation (214) of the toroidal coil carrier (21) is identical to the axis of rotation (214) of the toroidal body of the laminated structure (22).

7. 7. An electric drive according to claim 5 or 6, wherein the toroidal body has a cross-sectional area (222) that is at least three times as large, in particular at least five times as large, as the cross-sectional area (211) of the toroidal coil carrier (21).

8. the maximum radial extent (R1) of the toroidal coil carrier (21) when starting from the axis of rotation (214) is the same size as the maximum radial extent (R2) of the toroidal body of the laminated structure (22) when starting from the axis of rotation (214), or 8. An electric drive according to claim 5, wherein the minimum radial extent (R3) of the toroidal coil carrier (21) when starting from the axis of rotation (214) is equal to the minimum radial extent (R4) of the toroidal body of the laminated structure (22) when starting from the axis of rotation (214).

9. the winding extends radially further from the axis of rotation than the radially outermost region of the laminated structure; or 9. An electric drive device according to claim 1, wherein the windings extend to a region at a shorter radial distance from the axis of rotation than to a radially innermost region of the laminated structure.

10. Only one stator (2) and only one rotor (1), or Only two stators and only one rotor, 10. An electric drive arrangement according to claim 1 , comprising:

11. 11. An electric drive according to claim 1, wherein the toroidal coil carrier (21) has a maximum annular ring diameter, the size of which is at most 200 mm, in particular at most 100 mm, and / or at least 60 mm, in particular at least 80 mm.

12. 12. An electric drive according to any one of the preceding claims, wherein the stator (2) surrounds the rotor (1) or the rotor (1) surrounds the stator (2).

13. 13. An electric drive according to any one of the preceding claims, wherein the rotor (1) is a radial flux rotor or an axial flux rotor.

14. 14. An electric drive device according to claim 1, wherein the elliptical shape of the cross-sectional area of ​​the toroidal coil carrier has a major axis and a minor axis, the major axis being at most 1.3 times, in particular at most 1.2 times, longer than the minor axis.

15. An electric drive device as described in claim 8, wherein claims 1, 2, 3, and 5 are recited.

16. An electric drive device as described in claim 15 comprising only two stators and only one rotor.

17. An electric drive device as described in claim 9, wherein claims 1, 2, and 3 are cited.

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