HK40112948A - Electric drive having a toroidal coil carrier - Google Patents

Description

Electric drive device with ring coil frame

Technical Field

This invention relates to an electric drive device having a stator and a rotor. This description particularly includes the case of a radial flux motor having exactly one stator and exactly one rotor, and especially includes the case of an axial flux motor having two stators and one rotor. Furthermore, multiple coils are present.

Background Technology

An electric drive is a motor that converts electrical power into mechanical power. Current-carrying conductor coils generate a magnetic field, and the attractive and repulsive forces between these coils are converted into motion. In the case of an internal rotor, there are stationary outer components and rotating inner components within them. These components are called the stator and rotor.

In addition, electric motors are used in industries such as packaging and food, robotics, medical technology and medical assistive devices, or in motor vehicles such as electric bicycles, small vehicles and small aircraft.

Traditionally, for stator geometry, especially in the case of toothed coil windings, a rectangular tooth structure with side lengths _l1 and _l2 is used, where _l1 is typically much larger than _l2 . Side length _l1 is considered the winding that generates torque, and side length _l2 is considered the undesirable winding head. On the one hand, the variation in magnetic flux and therefore its amplitude should be maximized; on the other hand, the current heat loss in the winding should be minimized.

Summary of the Invention

The objective of this invention is to provide an electric drive device having a physically and mathematically optimized winding geometry.

This task is solved by the technical solution of the independent claim. Accordingly, the electric drive device includes a stator and a rotor. The stator is stationary and the rotor is moving. The rotor rotates the drive shaft. The electric drive device includes multiple turns of winding wire, which are wound into coils. The winding wire is, in particular, mostly made of copper wire, especially enameled copper wire.

An electric drive unit has a toroidal coil frame around which coils of winding wire are wound and supported. The term "toroidal coil frame" or "toroidal body" refers to a rotating body with a hole at its center. The axis of rotation passes through the hole and does not intersect the rotating body. Any cross-section, such as a square, can be rotated. If a circular cross-section is rotated, the toroidal body is called a "ring". The cross-section of a toroidal coil frame has an elliptical shape, especially a circular shape.

Applying coils to "segments" around a ring coil frame means that the coils do not exist along the entire rotational area, but only in partial segments.

A circle, as a cross-section, has the largest area with the smallest possible perimeter among all two-dimensional geometries. This minimizes the length of the enclosed wire. Consequently, current heat loss in the winding wire wound in a circle around a toroidal coil frame is also minimized. This is because current heat loss is a function of winding wire length. Alternatively, if the cross-section is designed as an ellipse instead of a circle, it is still better than a rectangular tooth structure in conventional electric drives, even if the geometry is not optimal.

Advantageously, the stator has a laminated structure comprising multiple laminations. Coils are wound around sections of a toroidal coil frame between each lamination. In particular, the toroidal coil frame and the laminated structure together constitute the stator. In larger stator geometries, the stator can be assembled and bonded from individual segments or from multiple components.

The addition of a lamination structure to the annular coil frame enables the use of conventional rotor structures. This can be either an axial flux rotor or a radial flux rotor. Without the lamination structure, the described electric drive device would be manufactured at extremely high costs.

In particular, the length of the laminated laminations extending along the rotational axis of the annular coil frame is greater than that of the annular coil frame itself. Therefore, a large stator exists that can receive the main magnetic flux from the rotor and allows for the use of a conventional rotor structure.

Especially in designs for radial flux motors, the length of the laminations extending along the rotation axis of the annular coil frame is at least twice, and especially at least three times, the length of the annular coil frame.

Advantageously, the laminated structure is constructed as a ring. The laminates form segments of this ring. Between these laminated segments are segments for the individual coil bodies of the windings.

In particular, the axis of rotation of the ring coil frame is the same as the axis of rotation of the ring body of the laminated structure.

Advantageously, the cross-section of the toroidal body is at least three times, and especially at least five times, the cross-section of the toroidal coil frame. This gives the stator a large air gap surface to receive the main magnetic flux from the rotor.

Advantageously, the maximum radial extension of the annular coil frame and the maximum radial extension of the annular body of the laminated structure are the same size, respectively, from the axis of rotation. In other words, the annular coil frame and the laminated structure, which together form the stator, are flush with each other on their respective outer sides. This design is particularly suitable for the case of an internal mover.

Alternatively, the minimum radial extension dimension of the annular coil frame, respectively, from the axis of rotation, can be the same as the minimum radial extension dimension of the annular body of the laminated structure. This design is particularly suitable for the case of an external mover.

The advantage of this stator geometry is that the coils wound by the winding wires partially protrude from the laminated structure and are therefore easily accessible to the cooling system.

In other words, the coil of the winding extends to a region radially further away from the axis of rotation than the outermost radial region of the laminated structure. This design is particularly suitable for internal movers.

Alternatively, the winding extends into a region radially closer to the axis of rotation than the radially innermost region of the laminated structure.

In particular, the electric drive device, in the design scheme of a radial flux motor, includes exactly one stator and exactly one rotor, and in the design scheme of an axial flux motor, it includes exactly two stators and exactly one rotor.

Advantageously, the maximum diameter of the annular coil frame is 200 mm, especially 100 mm and/or at least 60 mm, especially at least 80 mm. If the annular coil frame has a circular cross-sectional shape, the diameter of the circle is especially greater than 5 mm, especially greater than 10 mm and/or less than 20 mm, especially less than 15 mm.

In particular, the stator surrounds the rotor, meaning the rotor is located within the core of the stator. This refers to what is called an inner mover. Alternatively, the rotor surrounds the stator. This refers to what is called an outer mover. Advantageously, the rotor is a radial flux rotor.

If the cross-section of the ring coil frame is elliptical, then the major axis of the ellipse, especially the minor axis, is at most 1.3 times, and especially at most 1.2 times.

The stator is made of a 3D flux-conducting material with eddy current reduction mechanisms. This may include, for example, soft magnetic powder composites (SMC), ferrite, or nanocrystalline materials.

Attached Figure Description

Other design features, advantages, and applications of the invention will become apparent from the dependent claims and the following description based on the accompanying drawings. The drawings are as follows:

Figure 1a shows the first type of electric drive device arranged radially as an internal mover;

Figure 1b shows the stator of the first type of electric drive device without stator winding coils;

Figure 1c is a top view of a stator without stator windings;

Figure 1d is a cross-sectional view of the stator with the tangent passing through the statorless winding coil as shown in Figure 1c;

Figure 1e is a side view of a stator without stator windings;

Figure 1f is a cross-sectional view of the stator drawn with the tangent in Figure 1e through the stator, where the shaded area represents the coil of the stator winding;

Figure 2a shows the second type of electric drive device arranged radially as an external mover;

Figure 2b shows the stator of the second type of electric drive device without stator winding coils;

Figure 2c is a top view of a stator without stator windings;

Figure 2d is a cross-sectional view of the stator with the tangent passing through the statorless winding coil as shown in Figure 2c.

Figure 2e is a side view of a stator without stator windings;

Figure 2f is a cross-sectional view of the stator drawn with the tangent in Figure 2e through the stator, where the shaded area represents the coil of the stator winding;

Figure 3a shows the third type of electric drive device in an axial arrangement;

Figure 3b shows a stator component of the third type of electric drive device;

Figure 3c is a plan view of the stator component;

Figure 3d is a side view of the stator assembly; and

Figure 4 shows a cross-section of an elliptical geometry of a ring coil frame in an alternative embodiment.

Detailed Implementation

Figure 1a shows a first type of electric drive device. This first type of electric drive device includes a rotor 1 and a stator 2. Figures 1b to 1f show only the stator 2, wherein the coils of the winding 3 in Figure 1f are shown as shaded areas.

The stator 2 includes an annular coil frame 21. The annular coil frame 21 is a rotating body that rotates a cross-section 211. In this embodiment, the cross-section 211 is a circle with an exemplary radius of 6 mm. The coil 3 is wound around the annular coil frame 21. As described above, this coil is indicated by the shaded area in FIG1f.

The ring coil frame 21 only refers to such a portion of sub-2 around which the coil of the winding is wound. In this embodiment, this relates to a ring, which is defined inward by dashed line 212 and outward by solid circular line 213 in FIG. 1f.

The toroidal coil frame 21 is supplemented by the lamination structure 22. The stator 2 therefore includes the toroidal coil frame 21 and the lamination structure 22. The stator 2 is constructed integrally, but can be composed of bonded segments.

Between each lamination 221, sections 215 of the annular coil frame 21 are exposed, and the coil 3 is wound around these sections. That is, the coil 3 does not travel along the entire annulus, but only around the annular coil frame 21 in the sections 215 between each lamination 221. In this embodiment, the stator 2 or lamination structure 22 includes a total of twelve laminations 221 and twelve sections 215 of the annular coil frame 21 between each lamination 221.

Along the direction of the rotation axis 214, the lamination 221 extends over a length L1 that is longer than the length L2 of the annular coil frame 21, for example, 40 mm. The length L1 is approximately three times the length L2.

In this embodiment, the lamination structure 22 is also an annular body. This is because the lamination structure 22 is a body of revolution in which the cross-section 222, shown in shaded form in FIG. 1d, rotates about the axis of rotation 214. The axis of rotation of the annular coil frame 21 and the lamination structure 22 are the same. However, the lamination structure 22 is not continuous along the annulus, but exists only in segments. These segments of the lamination structure 22 are the laminations 221. The annular body of the lamination structure 22 is interrupted between the laminations, thereby forming gaps for the coils of the winding 3.

The cross-section 222 of the annular body of the laminated structure 22 is approximately six to seven times the cross-section 211 of the annular coil frame 21. This gives the stator 2 a large air gap surface to receive the main magnetic flux from the rotor.

The maximum radial extension dimension R1 of the annular coil holder 21 is exactly the same as the maximum radial extension dimension R2 of the laminated structure 22. This has the advantageous effect that a portion 31 of the coil 3 is exposed outside the stator 2 and is easily accessible to the cooling device 4. In other words, the coil of the winding 3 extends to a region radially further away from the axis of rotation 214 than the outermost radial region of the laminated structure 22. In this exemplary embodiment, radii R1 and R2 are 40 mm and correspond to the maximum annular diameter of the annular bodies of the annular coil holder 21 and the laminated structure 22.

Figure 2a shows a second type of electric drive device. This second type of electric drive device also includes exactly one rotor 1 and exactly one stator 2. Figures 2b to 2f show only the stator 2, where the winding 3 is indicated by a shaded area in Figure 2f. The reference numerals are the same as those used in Figures 1a to 1f. Since the rotor 1 surrounds the stator 2, this involves what is called an "outer mover".

The stator 2 is constructed based on the same principle as the stator 2 of the first type of electric drive device. It also includes an annular coil frame 21 with a circular cross-section 211, around which coils are applied in sections, and the windings consist of the coils.

The difference from the first type of electric drive is that the minimum radial extension dimension R3 of the toroidal coil frame 21 is exactly the same as the minimum radial extension dimension R3 of the laminated structure 22. This has the advantage that a portion 31 of the winding 3 is exposed within the stator 2 and is easily accessible to the cooling device 4. In other words, the winding 3 extends further radially closer to the axis of rotation 214 than the innermost radial region of the laminated structure 22.

Figures 3a and 3d show the inner mover in an axial arrangement. This includes a rotor 1 and a stator 2 with two stator components 2a and 2b. The two stator components 2a and 2b are constructed according to the same principle as the stators of the first and second electric drive devices. The difference is that the annular coil frame 21 is not radially outward, but rather flush with the outermost edge of the lamination structure 22 in the axial direction. The annular coil frame 21 and the lamination structure 22 are flush at the dashed line 23.

Figure 4 shows an ellipse 5. In one particular embodiment, the cross-section 211 of the annular coil holder 21 can have this ellipse 5 shape. For example, the ellipse has a major axis gA, which is 1.2 times the minor axis kA.

If the cross-section of the ring coil frame is elliptical, then the length of the major axis of the ellipse is at most 1.3 times, and especially at most 1.2 times, the length of the minor axis of the ellipse.

Although preferred embodiments of the invention have been described in this application, it should be clearly understood that the invention is not limited thereto and may be practiced in other ways within the scope of the appended claims.

Claims (14)

1. An electric drive device comprising a stator (2) and a rotor (1) and a plurality of coils of windings (3), characterized in that the stator (2) has an annular coil frame (21) with a rotation axis (214) and the annular coil frame (21) has an elliptical, in particular circular, cross-section (21), and the coils of the windings (3) are wound around a section (215) of the annular coil frame (21). 2. The electric drive device according to claim 1, wherein the stator (2) has a lamination structure (22) comprising a plurality of laminations (221), and the coils of the winding are applied between each lamination (221) around a section (215) of an annular coil frame (21). 3. The electric drive device according to claim 2, wherein the length of the lamination (221) extending in the direction of the rotation axis (214) of the annular coil frame (21) is greater than that of the annular coil frame (21). 4. The electric drive device according to claim 3, wherein the length of the lamination (221) extending in the direction of the rotation axis (214) of the annular coil frame (21) is at least two times, and especially at least three times, the length of the annular coil frame (21). 5. The electric drive device according to any one of claims 2 to 4, wherein the lamination structure (22) is configured as an annular body, and the lamination (221) is a segment of the annular body, and there are gaps between these segments for coils for winding (3). 6. The electric drive device according to claim 5, wherein the rotation axis (214) of the annular coil frame (21) is the same as the rotation axis (214) of the annular body of the laminated structure (22). 7. The electric drive device according to claim 5 or 6, wherein the cross-section (222) of the annular body is at least three times, and especially at least five times, the cross-section (221) of the annular coil frame (21). 8. The electric drive device according to any one of claims 5 to 7, wherein, from the rotation axis (214), the maximum radial extension dimension (R1) of the annular coil frame (21) and the maximum radial extension dimension (R2) of the annular body of the laminated structure (22) are the same; or Starting from the rotation axis (214), the minimum radial extension dimension (R3) of the annular coil frame (21) is the same as the minimum radial extension dimension (R4) of the annular body of the laminated structure (22). 9. The electric drive device according to any one of the preceding claims, wherein the winding extends to a region that is radially further away from the axis of rotation (214) than the radially outermost region of the laminated structure (22), or the winding extends to a region that is radially closer to the axis of rotation (214) than the radially innermost region of the laminated structure (22). 10. The electric drive device according to any one of the preceding claims, wherein the electric drive device has exactly one stator (2) and exactly one rotor (1); or the electric drive device has exactly two stators and exactly one rotor. 11. The electric drive device according to any one of the preceding claims, wherein the annular coil holder (21) has a maximum annular diameter, and the maximum annular diameter is at most 200 mm, especially at most 100 mm and/or at least 60 mm, especially at least 80 mm. 12. The electric drive device 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. The electric drive device according to any one of the preceding claims, wherein the rotor (1) is a radial flux rotor or an axial flux rotor. 14. The electric drive device according to any one of the preceding claims, wherein the elliptical shape of the cross-section of the annular coil frame has a major axis and a minor axis, wherein the length of the major axis is at most 1.3 times, and especially at most 1.2 times, the length of the minor axis.