Magnets, pole pieces and slot openings of an axial flux motor

Abstract

An axial flux motor comprises: a stator having a first side and a second side opposite to the first side, the stator comprising: N stator core components on the first side, wherein N is an integer greater than 2; and pole shoes attached to the radial sides of the N stator core components, N slot openings between adjacent pole shoes, wherein each of the N slot openings extends along at least one non-radial direction on the first side; and a rotor comprising a third side and M permanent magnets on the third side, wherein the first side is parallel to the third side, and wherein M is an integer greater than 2.

Description

[0001] introduction

[0002] The information provided in this section is intended to generally present the background of the present disclosure. To the extent described in this section, the work of the presently named inventors and aspects that may not otherwise qualify as prior art at the time of filing are neither expressly nor impliedly admitted to be prior art against the present disclosure. Technical Field

[0003] The present disclosure relates to electric motors, and more particularly to slot openings of a stator core of an electric motor. Background Art

[0004] Electric motors convert electrical energy into mechanical work by generating torque, while generators convert mechanical work into electrical energy. Electric vehicles (including hybrid vehicles) include electric motors / generators (such as induction motors and permanent magnet motors) to propel the vehicle and capture braking energy when used as generators. Reference will be made to electric motors in this article; however, it should be understood that this principle also applies to generators. Generally, an electric motor includes a rotor that rotates during operation and a stationary stator. The rotor may contain multiple permanent magnets and rotate relative to a fixed stator. The rotor is connected to a rotor shaft, which also rotates with the rotor. The rotor including permanent magnets is separated from the stator by a predetermined air gap. The stator includes a conductor in the form of a wire winding. When electrical energy is applied through the conductive wire winding, a magnetic field is generated. When electrical energy is fed into the conductive winding of the stator, power can be transferred through the air gap by generating a magnetic flux that acts on the permanent magnets in the rotor. In this way, mechanical power can be transferred to the rotating rotor shaft. In an electric vehicle, the rotor therefore transfers torque to the drive wheels of the vehicle via a rotating shaft through a gear set.

[0005] Two types of electric motors include radial flux type and axial flux type motors. In a radial flux motor, the rotor and stator are typically located in a concentric or nested configuration so that when the stator is energized, it produces a magnetic flux that extends radially from the stator to the rotor. Therefore, the conductive windings in the stator are typically arranged parallel to the axis of rotation so that a magnetic field is produced that is oriented in a radial direction from the axis of rotation (along the rotor axis). In an axial flux motor, the wire windings in the stator produce a magnetic field parallel to the axis of rotation, so the magnetic flux extends parallel to the axis of rotation (parallel to the rotor axis). In certain applications, axial flux motors are ideal because they are relatively lightweight, produce increased power, and have a compact size compared to radial flux motors. Summary of the invention

[0006] In one feature, an axial flux motor includes: a stator having a first side and a second side opposite the first side, the stator including: N stator core components on the first side, wherein N is an integer greater than 2; and pole shoes attached to radial sides of the N stator core components, N slot openings between adjacent pole shoes in the pole shoes, wherein each of the N slot openings extends in at least one non-radial direction on the first side; and a rotor including a third side and M permanent magnets on the third side, wherein the first side is parallel to the third side, and wherein M is an integer greater than 2.

[0007] In further features, at least one recess is formed in each of the N stator core components.

[0008] In further features, the at least one recess extends non-radially on the first side.

[0009] In further features, the at least one recess includes at least two recesses formed in each of the N stator core components.

[0010] In further features, electrically insulating material is located in each of the one or more recesses formed in each of the N stator core components.

[0011] In further features, air gaps are provided between the N stator core components and the permanent magnets.

[0012] In further features, the electrical conductor is at least one of: (i) wound around the N stator core components and (ii) wound through the N stator core components.

[0013] In further features, the N stator core components are made of a soft magnetic composite (SMC) material.

[0014] In further features, the pole piece is made of a soft magnetic composite (SMC) material.

[0015] In further features, the pole pieces are respectively adhered to the N stator core components via at least one of an adhesive and powder metallurgy forming.

[0016] In further features, more than one of the pole shoes includes: a first arched surface; a second arched surface located radially outward of the first arched surface; a first side surface connecting the first ends of the first arched surface and the second arched surface and extending along at least one non-radial direction on the first side; and a second side surface connecting the second ends of the first arched surface and the second arched surface and extending along at least one non-radial direction on the first side.

[0017] In further features, each of the M permanent magnets includes: a first arcuate surface; a second arcuate surface located radially outside the first arcuate surface; and at least one of the following: a third side surface connecting the first ends of the first arcuate surface and the second arcuate surface and extending along at least one non-radial direction on the third side of the rotor; and a fourth side surface connecting the second ends of the first arcuate surface and the second arcuate surface and extending along at least one non-radial direction on the third side of the rotor.

[0018] In further features, each of the M permanent magnets includes both of: a third side surface connecting the first ends of the first arcuate surface and the second arcuate surface and extending along at least one non-radial direction on the third side of the rotor; and a fourth side surface connecting the second ends of the first arcuate surface and the second arcuate surface and extending along at least one non-radial direction on the third side of the rotor.

[0019] In another feature, each of the M permanent magnets includes: a first arcuate surface; a second arcuate surface located radially outside the first arcuate surface; a third side surface extending radially outward along a first direction from a first end of the first arcuate surface; a fourth side surface extending radially outward along a second direction to the first end of the second arcuate surface; a fifth side surface connecting the third side surface and the fourth side surface; a sixth side surface extending radially outward along a third direction from the second end of the first arcuate surface; a seventh side surface extending radially outward along a fourth direction to the second end of the second arcuate surface; and an eighth side surface connecting the sixth side surface and the seventh side surface, wherein the first, second, third and fourth directions are different from each other.

[0020] In further features, the fifth side surface is perpendicular to both the third and fourth side surfaces.

[0021] In further features, the eighth side surface is perpendicular to both the sixth and seventh side surfaces.

[0022] In further features, the fifth side surface forms an oblique angle with the third and fourth side surfaces; and the eighth side surface forms an oblique angle with the sixth and seventh side surfaces.

[0023] In one feature, an axial flux motor includes: a stator having a first side and a second side opposite the first side, the stator including: N stator core components on the first side, wherein N is an integer greater than 2; and pole shoes attached to the sides of the N stator core components; N slot openings between adjacent pole shoes in the pole shoes; and a rotor including a third side and M permanent magnets on the third side, wherein the first side is parallel to the third side, and wherein M is an integer greater than 2, and wherein each of the M permanent magnets includes: a first arcuate surface; a second arcuate surface located radially outside the first arcuate surface; and at least one of the following: a third side surface connecting the first ends of the first arcuate surface and the second arcuate surface and extending along at least one non-radial direction on the third side of the rotor; and a fourth side surface connecting the second ends of the first arcuate surface and the second arcuate surface and extending along at least one non-radial direction on the third side of the rotor.

[0024] In further features, each of the M permanent magnets includes both of: a third side surface connecting the first ends of the first arcuate surface and the second arcuate surface and extending along at least one non-radial direction on the third side of the rotor; and a fourth side surface connecting the second ends of the first arcuate surface and the second arcuate surface and extending along at least one non-radial direction on the third side of the rotor.

[0025] In one feature, an axial flux motor comprises: a stator having a first side and a second side opposite the first side, the stator comprising: N stator core components on the first side, wherein N is an integer greater than 2; and pole shoes attached to the sides of the N stator core components; N slot openings between adjacent pole shoes in the pole shoes; and a rotor comprising a third side and M permanent magnets on the third side, wherein the first side is parallel to the third side, and wherein M is an integer greater than 2, and wherein each of the M permanent magnets comprises: a first arcuate surface; a second arcuate surface located a radially outer side of the first arched surface; a third side surface extending radially outward along the first direction from the first end of the first arched surface; a fourth side surface extending radially outward along the second direction to the first end of the second arched surface; a fifth surface connecting the third side surface and the fourth side surface; a sixth side surface extending radially outward along the third direction from the second end of the first arched surface; a seventh side surface extending radially outward along the fourth direction to the second end of the second arched surface; and an eighth surface connecting the sixth side surface and the seventh side surface, wherein the first, second, third and fourth directions are different from each other.

[0026] The present invention proposes the following technical solutions:

[0027] 1. An axial flux motor, comprising:

[0028] A stator having a first side and a second side opposite the first side, the stator comprising:

[0029] N stator core components on the first side,

[0030] Wherein N is an integer greater than 2; and

[0031] pole shoes attached to the radial sides of the N stator core components,

[0032] N slot openings between adjacent ones of the pole shoes, wherein each of the N slot openings extends in at least one non-radial direction on the first side; and

[0033] a rotor comprising a third side and M permanent magnets on the third side,

[0034] wherein the first side is parallel to the third side, and

[0035] Here, M is an integer greater than 2.

[0036] 2. The axial flux motor according to technical solution 1, wherein the plurality of pole shoes comprises:

[0037] a first arcuate surface;

[0038] a second arcuate surface located radially outward of the first arcuate surface;

[0039] a first side surface connecting first ends of the first arcuate surface and the second arcuate surface and extending in at least one non-radial direction on the first side; and

[0040] A second side surface connects the first arcuate surface and the second end of the second arcuate surface and extends in at least one non-radial direction on the first side.

[0041] 3. The axial flux motor according to technical solution 1, wherein each of the M permanent magnets comprises:

[0042] a first arcuate surface;

[0043] a second arcuate surface located radially outward of the first arcuate surface; and

[0044] At least one of the following:

[0045] a third side surface connecting first ends of the first and second arcuate surfaces and extending in at least one non-radial direction on the third side of the rotor; and

[0046] A fourth side surface connects the second ends of the first and second arcuate surfaces and extends in at least one non-radial direction on the third side of the rotor.

[0047] 4. The axial flux motor according to technical solution 3, wherein each of the M permanent magnets includes the following two:

[0048] a third side surface connecting first ends of the first and second arcuate surfaces and extending in at least one non-radial direction on the third side of the rotor; and

[0049] A fourth side surface connects the second ends of the first and second arcuate surfaces and extends in at least one non-radial direction on the third side of the rotor.

[0050] 5. The axial flux motor according to technical solution 1, wherein each of the M permanent magnets comprises:

[0051] a first arcuate surface;

[0052] a second arcuate surface located radially outward of the first arcuate surface;

[0053] a third side surface extending radially outwardly in a first direction from a first end of the first arcuate surface;

[0054] a fourth side surface extending radially outwardly in a second direction to a first end of the second arcuate surface;

[0055] a fifth side surface connecting the third side surface and the fourth side surface;

[0056] a sixth side surface extending radially outwardly from the second end of the first arcuate surface along a third direction;

[0057] a seventh side surface extending radially outwardly along a fourth direction to a second end of the second arcuate surface; and

[0058] an eighth side surface connecting the sixth side surface and the seventh side surface,

[0059] Wherein, the first, second, third and fourth directions are different from each other.

[0060] 6. An axial flux motor according to technical solution 5, wherein the fifth side surface is perpendicular to both the third side surface and the fourth side surface.

[0061] 7. An axial flux motor according to technical solution 5, wherein the eighth side surface is perpendicular to both the sixth side surface and the seventh side surface.

[0062] 8. The axial flux motor according to technical solution 5, wherein:

[0063] The fifth side surface forms an oblique angle with the third and fourth side surfaces; and

[0064] The eighth side surface forms an oblique angle with the sixth and seventh side surfaces.

[0065] 9. An axial flux motor, comprising:

[0066] A stator having a first side and a second side opposite the first side, the stator comprising:

[0067] N stator core components on the first side,

[0068] Wherein N is an integer greater than 2; and

[0069] pole shoes attached to sides of the N stator core components;

[0070] N slot openings between adjacent ones of the pole shoes; and

[0071] a rotor comprising a third side and M permanent magnets on the third side,

[0072] wherein the first side is parallel to the third side, and

[0073] Wherein, M is an integer greater than 2, and

[0074] Wherein, each of the M permanent magnets comprises:

[0075] a first arcuate surface;

[0076] a second arcuate surface located radially outward of the first arcuate surface; and

[0077] At least one of the following:

[0078] a third side surface connecting first ends of the first arcuate surface and the second arcuate surface and extending in at least one non-radial direction on the third side of the rotor; and

[0079] A fourth side surface connects the first arcuate surface and the second arcuate surface at second ends and extends in at least one non-radial direction on a third side of the rotor.

[0080] 10. The axial flux motor according to technical solution 9, wherein each of the M permanent magnets includes the following two:

[0081] a third side surface connecting first ends of the first arcuate surface and the second arcuate surface and extending in at least one non-radial direction on the third side of the rotor; and

[0082] A fourth side surface connects the first arcuate surface and the second arcuate surface at second ends and extends in at least one non-radial direction on the third side of the rotor.

[0083] 11. An axial flux motor, comprising:

[0084] A stator having a first side and a second side opposite the first side, the stator comprising:

[0085] N stator core components on the first side,

[0086] Wherein N is an integer greater than 2; and

[0087] pole shoes attached to sides of the N stator core components;

[0088] N slot openings between adjacent ones of the pole shoes; and

[0089] a rotor comprising a third side and M permanent magnets on the third side,

[0090] wherein the first side is parallel to the third side, and

[0091] Wherein, M is an integer greater than 2, and

[0092] Wherein, each of the M permanent magnets comprises:

[0093] a first arcuate surface;

[0094] a second arcuate surface located radially outward of the first arcuate surface;

[0095] a third side surface extending radially outwardly in a first direction from a first end of the first arcuate surface;

[0096] a fourth side surface extending radially outwardly in a second direction to a first end of the second arcuate surface;

[0097] a fifth side surface connecting the third side surface and the fourth side surface;

[0098] a sixth side surface extending radially outwardly from the second end of the first arcuate surface along a third direction;

[0099] a seventh side surface extending radially outwardly along a fourth direction to a second end of the second arcuate surface; and

[0100] an eighth surface connecting the sixth side surface and the seventh side surface,

[0101] Wherein, the first, second, third and fourth directions are different from each other.

[0102] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the accompanying drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0103] The present disclosure will be more fully understood from the detailed description and accompanying drawings, wherein:

[0104] Figure 1 An example axial flux electric machine having one stator and two rotors is shown;

[0105] Figure 2 A laminated stator core component including a plurality of laminated layers is shown;

[0106] Figure 3 A stator core component is shown;

[0107] Figure 4 shows an image Figure 3 A stator having a plurality of stator core components as described in;

[0108] Figure 5 Included in the Figure 3 Example graphs of cogging torque versus rotor position during rotor rotation of stator core components and pole pieces;

[0109] Figure 6 and 7 is a perspective view of the stator viewed from a first side of the stator;

[0110] Figure 8 is another perspective view of the stator viewed from a first side of the stator;

[0111] Fig. 9 is an example graph of cogging torque versus rotor position during rotor rotation;

[0112] Fig.10 , 11 , 12 and 13 include perspective views of the stator;

[0113] Fig.14 is another perspective view of the stator viewed from a first side of the stator;

[0114] Fig.15 including example graphs of cogging torque versus rotor position during rotor rotation;

[0115] Fig.16 and17 a perspective view including permanent magnets of the rotor; and

[0116] Fig.18A and 18B Includes example illustrations of rectangular permanent magnet blocks that may be used to form permanent magnets for a rotor.

[0117] In the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0118] The present application relates to stator and rotor components for axial flux electric machines. These concepts are applicable not only to axial flux electric machines that generate mechanical energy from electrical energy, but also to axial flux generators that can generate electrical energy from mechanical energy.

[0119] The teeth of the stator define slots between adjacent teeth of the teeth. The winding is inserted into the slots and wound around the teeth. The teeth can have the same shape, and the shape of the teeth can be such that the slots between adjacent teeth extend radially. Pole shoes can be attached to the sides of the teeth to reduce the width of the slot opening so as to concentrate more magnetic flux paths through the teeth and thereby improve the performance of the motor. The pole shoes can also have the same shape, and the shape of the pole shoes can be such that the slot openings between adjacent pole shoes extend radially. In summary, the teeth define slots between adjacent teeth of the teeth, wherein the winding is inserted into the slots and wound around the teeth. The pole shoes define slot openings between adjacent pole shoes. Therefore, the slot opening is the end of the slot close to the air gap surface. However, by such an arrangement structure of the teeth, pole shoes, slots and slot openings, the cogging torque can vary as the motor rotates.

[0120] The present application relates to slot openings extending in at least one non-radial direction to reduce variations in cogging torque of an electric motor. Additionally or alternatively, the present application relates to permanent magnets of a rotor having a non-conventional shape to reduce cogging torque.

[0121] Figure 1 An exploded view of a non-limiting example of an (electric) axial flux electric machine 100 (also referred to as a pancake electric machine) is shown in FIG. The axial flux electric machine 100 may be used, for example, in a vehicle or other suitable type of device. In a vehicle, the electric machine 100 may be used, for example, to generate torque that may be transferred to one or more wheels of the vehicle and / or to convert kinetic energy from the one or more wheels into electrical energy (e.g. for regeneration).

[0122] The electric machine 100 includes a first rotor 110 and a second rotor 120, both of which are connected to a rotor shaft 130 and are configured to rotate about the rotor shaft 130. The first rotor 110 and the second rotor 120 both have an annular or disc shape and have a centrally disposed hole 118. The rotor shaft 130 passes through the centrally disposed hole 118. The rotor shaft 130 defines an axis of rotation 132 about which the rotors 110 and 120 rotate.

[0123] The stator 140 is disposed between the first rotor 110 and the second rotor 120. The stator 140 may have a ring or disk shape. The stator 140 is fixed and stationary, while the first rotor 110 and the second rotor 120 rotate together with the rotor shaft 130 during operation. One side of the first rotor 110 faces a first side 142 of the stator 140, and a first air gap 144 is defined therebetween. The first side 142 of the stator 140 exists along a first plane. One side of the second rotor 120 faces a second side 146 of the stator 140, and a second air gap 148 is defined therebetween. The second side 146 of the stator 140 exists along a second plane. The first and second planes are parallel and do not intersect.

[0124] Although the motor 100 is shown as having one stator and two rotors, the present application may also be applicable to other numbers of stators and / or rotors, including multiple stators, a single rotor, or more than two rotors. For example, the present application may also be applicable to a motor having a single rotor motor, a motor having a single stator, a motor having a single rotor between two stators, and a motor having a single stator between two rotors. The following description also applies to these other embodiments. Although not shown, the motor 100 includes a housing, and the rotor, stator, and rotor shaft are disposed within the housing. The rotor shaft 130 typically extends to the outside of the housing through a hole in the housing. The housing may be fixed to, for example, a vehicle frame, and the rotor shaft may be coupled to a gearbox within the vehicle, such as a reduction gearbox.

[0125] The first rotor 110 and the second rotor 120 may have the same design or a similar design (facing in opposite directions toward the stator 140 ), and thus the common components will be described herein.

[0126] Each of the first rotor 110 and the second rotor 120 includes a plurality of permanent magnets 112 fixed to a rotor body 114. The permanent magnets 112 may have alternating polarities. For example, one permanent magnet 112 may have a positive polarity, the next adjacent permanent magnet 112 may have a negative polarity, the next adjacent permanent magnet 112 may have a positive polarity, and so on. The permanent magnets 112 are separated from each other by channels such as channels 116. The channels may extend radially along the respective rotor faces. The permanent magnets 112 and channels 116 may together define a plurality of magnetic poles.

[0127] The stator 140 includes a plurality of stator segments or core members 150, and a plurality of conductive windings 152 are wound (wound) around the stator segments or core members 150 (around the stator segments or core members 150). The stator core members 150 may also be referred to as teeth. The stator 140 defines a plurality of slots 156 between the stator core members 150. The conductive windings 152 may extend over or bridge the slots 156. The stator 140 may be fixed and stationary. Although an example winding configuration is shown, the present application may also be applicable to other winding configurations. For example, in some aspects, the slots 156 may be configured to receive the conductive windings 152, which are wound in and through the slots 156. The conductive wires or windings 152 may include, for example, copper, a copper alloy, or another type of electrical conductor.

[0128] The rotor shaft 130 may pass through a hole 154 centrally disposed in the stator 140 and be supported by one or more bearings that align the first rotor 110 and the second rotor 120 relative to the stator 140 while allowing the rotor shaft 130 to rotate. The conductive windings 152 of the stator 140 may be formed of copper or other conductive wires that are configured to generate a magnetic field when an electric current is applied to interact with the magnetic fields of the plurality of permanent magnets 112 having alternating polarities located on the first rotor 110 and the second rotor 120.

[0129] Different regions of the stator 140 may be selectively energized to impart a rotational force on the first rotor 110 and the second rotor 120, thereby rotating the rotors 110 and 120 and the rotor shaft 130 relative to the rotation axis 132. For example, the stator component 150 may be sequentially energized in a counterclockwise direction or a clockwise direction to impart a clockwise or counterclockwise rotation to the rotor shaft 130.

[0130] The electric machine 100 having a single stator 140 and a first rotor 110 and a second rotor 120 can be used for high torque applications, including in electric vehicles or hybrid vehicles. In such an embodiment, the housing encapsulating the electric machine 100 can be fixed / attached to the vehicle frame, and at least one output from one end of the rotor shaft 130 is coupled to a reduction gearbox or directly to the vehicle drive wheels. Although an example of an electric machine 100 implemented in a vehicle is provided, the present application is not limited to a vehicle-based example.

[0131] Figure 2-4 A stator core component is shown which may be used in the stator of an axial flux electric machine, such as Figure 1 The stator 140. The conductive wire is arranged around or wound around the outside of the stator.

[0132] Figure 2A laminated stator core component 200 is shown having multiple layers 210 of magnetic material, such as a ferromagnetic material like magnetic steel or another type of ferromagnetic material. Such layers of magnetic material may be isolated from each other by insulating material sandwiched between the layers of magnetic material. The laminated steel sheets may be stamped, optionally annealed, and stacked during the manufacturing process to form the laminated stator core component. When multiple laminated stator core components are assembled together, they form a plurality of magnetizable poles.

[0133] As can be seen, the stator core component 200 may include an assembly of multiple different laminated layer structures or modules, which may have different orientations relative to each other. In other aspects, the multiple laminated modules may have substantially the same orientation relative to each other. Although in Figure 2 Although not shown, each magnetic pole defined by a stator core segment may have an electrically conductive wire disposed at least partially thereabout or wound around it. When such a laminated stator core segment is incorporated into the stator of an axial flux machine, it may have the advantages of reducing eddy currents and minimizing hysteresis. Although Figure 2 and Figure 3 Example shapes for stator core components are shown, but the present application is directed to more complex stator core component shapes, as discussed further below.

[0134] like Figure 2 As shown, the first layer 212 has a first dimension defined by its length, width, and height (e.g., thickness), while the second layer 214 in the stack has a second dimension defined by its length, width, and height (e.g., thickness). Due to the substantially trapezoidal shape of the stator core component 200, the second dimension of the second layer 214 must be smaller than the first dimension of the first layer 212.

[0135] Figure 3-4 Another option for forming a stator core component is shown, in which the stator core component 200 is formed of a soft magnetic composite material (SMC) 222. The SMC powder may include a soft magnetic material, the surface of which may be covered with an electrically insulating layer. These powders may be formed into soft magnetic components, for example, by pressing or another consolidation method. Although an example is provided in which the stator core component 200 has trapezoidal faces and a thickness between the trapezoidal faces, the stator core component 200 may have another suitable shape. Each stator core component 200 includes trapezoidal teeth 236 and pole shoes 300 extending outward from opposite sides of the stator core component. The pole shoes 300 may be attached, for example, by powder metallurgy forming or another suitable attachment form. The pole shoes 300 may form one or more flanges. The pole shoes 300 define a recessed area 226 together with the teeth 236. The area 226 is a slot, and each slot has two slot openings at its two ends in the axial direction defined by the pole shoes 300. The pole shoes 300 define slot openings between adjacent pole shoes on adjacent stator core components. Although Figure 3One example pole shoe shape is shown in , but the present application is contemplated by other pole shoe shapes, as discussed further below.

[0136] Figure 4 A plurality of stator core segments 200 are shown assembled along the circumference on a stator disk 230. Channels (slots) 232 are defined between the stator core segments 200. Figure 4 As shown, the recessed area 226 is configured to receive at least one conductive wire or winding 234 disposed therein (e.g., by being wound around at least a portion of the exterior of the stator core component 200). The slot opening is defined between the pole pieces 300 on opposite sides of the teeth 236. The stator core component 200 formed from the SMC material 222 can be manufactured into a variety of complex shapes. Therefore, different shapes of the slot openings can be achieved by changing the shape of the pole pieces 300, as discussed further below.

[0137] Figure 5 Included in the Figure 3 An example graph of cogging torque (in Newton meters (Nm)) 500 versus rotor position 504 during rotor rotation of a stator core component and pole piece of FIG. Cogging torque is introduced by the magnetic flux switching from one tooth to the next and passing through the slot openings as the permanent magnets of the rotor rotate. Figure 5 As shown, the peak-to-peak fluctuation in the cogging torque is approximately 25 Nm.

[0138] According to the present disclosure, the pole shoes attached to the stator core components are formed so that the slot openings between adjacent pole shoes of different stator core components extend in a non-radial direction. In other words, the slot openings extend at a non-zero (inclination) angle relative to all radii of the stator. In other words, the slot openings extend in at least one non-radial direction. The radius of the stator is perpendicular to the rotor axis and extends radially outward from the center of the hole 154 on the plane of the face of the stator. In various embodiments, as further discussed below, the stator core component may optionally include one or more recesses having the same shape as the slot opening to form a quasi (virtual) slot. The pole shoes may be made of, for example, SMC material. The pole shoes may be pressed and stamped, for example.

[0139] Figure 6 6 is a perspective view of the stator 600 as viewed from the first side 142 of the stator 600. The stator 600 includes pole pieces 604 and slot openings 608 between the pole pieces 604. The pole pieces 604 may be identical and equally spaced around the stator 600. Thus, the slot openings 608 between the pole pieces 604 are also identical. The terms slot, opening, and slot opening as used herein may be interchangeable.

[0140] The pole shoes of the pole shoes 604 attached to the left side (when viewed from the first side 142) of the stator core component 200 may each include an inner arcuate surface 612 and an outer arcuate surface 616. These pole shoes of the pole shoes 604 also each include a first linear surface 620 connecting the first ends of the inner arcuate surface 612 and the outer arcuate surface 616 and a second linear surface 624 connecting the second ends of the inner arcuate surface 612 and the outer arcuate surface 616. The pole shoes of the pole shoes 604 attached to the right side (when viewed from the first side 142) of the stator core component 200 may each include an outer arcuate surface 625, a first linear surface 626, and a second linear surface 627.

[0141] exist Figure 6 In the example of , the slot opening 608 extends non-radially. The slot opening 608 extends linearly at a non-zero angle relative to all radii (such as radius 628) of the first side 142 of the stator 600. The slot opening 608 forms an oblique angle relative to all radii of the first side 142. An oblique angle may refer to all angles that are not a right angle (90 degrees) or an integer multiple of a right angle (90 degrees).

[0142] For example, a radius 628 is drawn between the center of the stator 600 and a radially inner midpoint 632 between two adjacent pole pieces 604. A line 636 along which the slot opening 608 extends forms a predetermined angle θ relative to the radius 628. The predetermined angle may be, for example, 3-15 degrees or another suitable angle. Each slot opening 608 forms the same predetermined angle θ relative to the radius between the center of the stator 600 and the radially inner midpoint between the two adjacent pole pieces 604 forming the slot opening. Although Figure 6 In the example of FIG. 6 , line 636 is a predetermined angle in a counterclockwise direction from radius 628, but slot opening 608 may be oriented such that line 636 is a predetermined angle in a clockwise direction from radius 628, such as Figure 7 For example, the predetermined angle may be selected to minimize cogging torque ripple.

[0143] Figure 8 is another perspective view of the stator 600 as viewed from the first side 142 of the stator 600. Figure 8 In the example of, one or more recesses 804 are formed in the outer surface of each stator core component on the plane of the first side 142. Although an example of two recesses formed in each stator core component is provided, one recess or more than two recesses may alternatively be formed in each stator core component. In various embodiments, the recesses may be formed during pressing of the stator core components, or removed from the stator core components after manufacturing. In various embodiments, the recesses may be filled with different materials (such as non-magnetic materials), or left unfilled. For example, the number of recesses and the size of the recesses may be selected to minimize cogging torque. The recesses form quasi (virtual) slots.

[0144] Fig. 9 is an example graph of cogging torque (in Nm) 900 versus rotor position 904 during rotor rotation. Trace 908 is based on a curve having a rotational speed similar to Figure 3 Trace 912 corresponds to a motor having a stator core component and pole shoes similar to Figure 6 and 7 Trace 916 corresponds to a motor having a stator core component, pole shoes, and slot openings similar to Figure 8 An electric motor having a stator core member, a pole shoe, and a slot opening (including a recess formed in the stator core member). Fig. 9 As shown, relative to Figure 3 For example, Figure 6 and 7 The example can reduce the cogging torque ripple. Figure 6 and 7 For example, Figure 8 An example of reducing cogging torque ripple.

[0145] Fig.10 , 11 and 12 include perspective views of stator 1000 . Fig.10 Included is a perspective view of the stator 1000 viewed from the first side 142 of the stator 1000 . Fig.12 Only a portion of the stator 1000 is shown from the first side 142 . Fig.11 is a cross-sectional view of the stator 1000, which is cut from the middle plane and is Fig.10 In other words, Fig.11 Is the stator 1000 into the other half of the page in the figure, not Fig.10 The half shown.

[0146] Stator 600 includes pole pieces 1004 and slot openings 1008 between pole pieces 1004. Each pole piece 1004 attached to the left side of stator core component 200 can be identical. Each pole piece 1004 attached to the right side of stator core component 200 can be identical. Therefore, the slot openings 1008 between pole pieces 1004 are also identical. Figure 10-12 In the example of FIG. 1 , the slot openings 1008 are V-shaped and extend in two non-radial directions relative to their respective sides of the stator 1000. Fig.12 As shown, when flipped over, the pole pieces 1004 and slot openings 1008 on the second side 146 of the stator 1000 may be identical to the pole pieces 1004 and slot openings 1008 located on the first side 142 of the stator 1000 .

[0147] exist Figure 10-12In the example of , the slot opening 1008 extends in two non-radial directions. The slot opening 1008 extends linearly at a non-zero angle relative to all radii (such as radius 1028) of the first side 142 of the stator 1000. For example, the radius 1028 is drawn between the center of the stator 1000 and the radially inner midpoint 1032 between two adjacent pole shoes 1004. The slot opening 1008 extends along a first line 1036 that forms a (non-zero) first predetermined angle relative to the radius 1028. The first line 1036 also forms a non-zero angle relative to all other radii of the first side 142. The predetermined angle is an oblique angle. The slot opening 1008 also extends along a second line 1040. The second line 1040 forms a (non-zero) second predetermined angle relative to the radius 1028. The second line 1040 also forms a non-zero angle relative to all other radii of the first side 142.

[0148] Each slot opening 1008 forms the same angle relative to the center of the stator 1000 and the radius between the radially inner midpoints between the two adjacent pole pieces 1004 forming the slot. Fig.10 The example of illustrates that the first line 1036 is located in the counterclockwise direction from the radius 1028, but the slot opening 1008 can be oriented so that the first line 1036 is located in the clockwise direction from the radius 1028, such as Fig.13 In other words, Fig.10 The pole piece 1004 of the example can be flipped horizontally, such as Fig.13 shown.

[0149] Fig.14 is another perspective view of the stator 1000 as viewed from the first side 142 of the stator 1000. Fig.14 In the example of, one or more recesses 1404 are formed in the outer surface of each stator core component 200 on the plane of the first side 142. Although an example of two recesses formed in each stator core component is provided, one recess or more than two recesses may alternatively be formed in each stator core component. In various embodiments, the recesses may be formed during pressing of the stator core components, or removed from the stator core components after manufacturing. In various embodiments, the recesses may be filled with different materials (such as non-magnetic materials), or left unfilled. For example, the number of recesses and the size of the recesses may be selected to minimize cogging torque. The recesses form quasi (virtual) slots.

[0150] Fig.15 An example graph of cogging torque (in Nm) 1500 versus rotor position 1504 during rotor rotation is included. Trace 1508 is based on a curve having a rotational speed similar to Figure 3 Trace 1512 corresponds to a motor having a stator core component and pole shoes similar to Figure 10-12Trace 1516 corresponds to a motor having a stator core component, pole shoes, and slot openings similar to Fig.13 A motor having a stator core component (with a recess), a pole shoe and a slot. Fig.15 As shown, relative to Figure 3 For example, Figure 10-13 The example can reduce the cogging torque ripple. Figure 10-13 For example, Fig.14 The example can also reduce the slot torque ripple.

[0151] The permanent magnets 112 on the rotor may have Figure 1 As an alternative or in addition to slot openings extending in one or more non-radial directions, the permanent magnets 112 on the rotor may have a different shape.

[0152] Fig.16 A perspective view of a permanent magnet 1600 comprising a rotor having a Figure 1 The permanent magnets 112 of the motor may have different shapes. All permanent magnets on the motor may have the same shape.

[0153] Permanent magnet 1600 includes an inner arcuate surface 1604 and an outer arcuate surface 1608. Inner arcuate surface 1604 is located radially inward of outer arcuate surface 1608 on the rotor.

[0154] The first end of the inner arcuate surface 1604 is connected to the first end of the outer arcuate surface via the first surface 1612, the second surface 1616, and the third surface 1620. The first surface 1612 and the third surface 1620 can be linear. The second surface 1616 can be perpendicular to both the first surface 1612 and the third surface 1620. The second surface 1616 can be linear or arcuate. The second surface 1616 can form an angle different from 90 degrees with the first surface 1612 and the third surface 1620. With this arrangement, the first surface 1612 is aligned with the first radius 1624 of the rotor, the third surface 1620 is aligned with the second radius 1628 of the rotor, and the first radius 1624 is different from the second radius 1628 (angularly offset from the second radius 1628).

[0155] The second end of the inner arcuate surface 1604 is connected to the second end of the outer arcuate surface via the fourth surface 1632, the fifth surface 1636, and the sixth surface 1640. The fourth surface 1632 and the sixth surface 1640 may be linear. The fifth surface 1636 may be linear or arcuate. The fifth surface 1636 may be perpendicular to both the fourth surface 1632 and the sixth surface 1640. However, the fifth surface 1636 may form an angle different from 90 degrees with the fourth surface 1632 and the sixth surface 1640. With this arrangement, the fourth surface 1632 is aligned with the third radius 1644 of the rotor, the sixth surface 1640 is aligned with the fourth radius 1648 of the rotor, and the third radius 1644 is different from the fourth radius 1648 (angledly offset from the fourth radius 1648).

[0156] Fig.17 A perspective view of a permanent magnet 1700 comprising a rotor having Figure 1 The permanent magnets 112 of the motor may have different shapes. All permanent magnets on the motor may have the same shape.

[0157] Permanent magnet 1700 includes an inner arcuate surface 1704 and an outer arcuate surface 1708. Inner arcuate surface 1704 is located radially inward of outer arcuate surface 1708 on the rotor.

[0158] The first end of the inner arcuate surface 1704 is connected to the first end of the outer arcuate surface 1708 via a first linear surface 1712. Although an example of the first linear surface 1712 is provided, the first surface 1712 may be non-linear. The second end of the inner arcuate surface 1704 is connected to the second end of the outer arcuate surface 1708 via a second linear surface 1716. Although an example of the second linear surface 1716 is provided, the first surface 1716 may be non-linear. The first linear surface 1712 extends along a first line 1720 and extends non-radially relative to the rotor. In other words, the first linear surface 1712 forms a non-zero angle relative to all radii of the rotor. The second linear surface 1716 extends along a second line 1724 and extends non-radially relative to the rotor. In other words, the second linear surface 1716 forms a non-zero angle relative to all radii of the rotor.

[0159] Example radius 1728 and 1732 in Fig.17 , and intersect at the (radial) center 1736 of the rotor. Because the first line 1720 and the second line 1724 extend non-radially, the first line 1720 and the second line 1724 intersect at a position different from the rotor center 1736. Fig.16 Example or Fig.17 The example shape of the permanent magnet can reduce the cogging torque of the motor.

[0160] Although examples of arcuate permanent magnets are provided, the permanent magnets may be formed from a plurality of rectangular permanent magnets forming an overall pattern of arcuate surfaces. Multiple layers of rectangular permanent magnets may be used to produce one of the permanent magnets discussed above. The rectangular permanent magnets may be skewed so that the centerline of a given layer of rectangular magnet blocks is displaced relative to the center of the rotor. Fig.18B An example of a rectangular permanent magnet that can be used to form one of the permanent magnets discussed above is provided, where the centerline of the rectangular magnet block layer is displaced relative to the center of the rotor. Fig.18A Also included are rectangular permanent magnets, but the center lines of the rectangular magnet blocks are not relative to Fig.18A The rotor center is displaced.

[0161] The foregoing description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because after studying the drawings, the specification and the appended claims, other modifications will become apparent. It should be understood that one or more steps in the method can be performed in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented in any other embodiment and / or combined with the features of any one of the other embodiments, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the replacement of one or more embodiments with each other is still within the scope of the present disclosure.

[0162] Various terms are used to describe the spatial and functional relationships between elements (e.g., relationships between modules, circuit elements, semiconductor layers, etc.), including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "above," "below," and "disposed." Unless explicitly described as "directly," when describing the relationship between a first and a second element in the above disclosure, the relationship may be a direct relationship in which there are no other intervening elements between the first and second elements, but may also be an indirect relationship in which there are one or more intervening elements (either spatially or functionally) between the first and second elements. As used herein, the phrase "at least one of A, B, and C" should be interpreted to mean a logical (A or B or C) using a non-exclusive logical "or," and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

Claims

1. An axial flux motor, comprising: A stator having a first side and a second side opposite the first side, the stator comprising: N stator core components on the first side, Wherein N is an integer greater than 2; and pole shoes attached to the radial sides of the N stator core components, N slot openings between adjacent ones of the pole shoes, wherein each of the N slot openings extends non-radially in at least one direction on the first side; and a rotor comprising a third side and M permanent magnets on the third side, wherein the first side is parallel to the third side, and Wherein, M is an integer greater than 2; Wherein, a plurality of said pole shoes include: a first arcuate surface; a second arcuate surface located radially outward of the first arcuate surface; a first side surface connecting first ends of the first arcuate surface and the second arcuate surface and extending non-radially in at least one direction on the first side; and A second side surface connects the first arcuate surface and the second end of the second arcuate surface and extends non-radially in at least one direction on the first side.

2. The axial flux motor according to claim 1, wherein: Each of the M permanent magnets comprises: a first arcuate surface; a second arcuate surface located radially outward of the first arcuate surface; and At least one of the following: a third side surface connecting first ends of the first and second arcuate surfaces and extending non-radially in at least one direction on the third side of the rotor; and A fourth side surface connects the second ends of the first and second arcuate surfaces and extends non-radially in at least one direction on the third side of the rotor.

3. The axial flux motor according to claim 1, wherein: Each of the M permanent magnets comprises: a first arcuate surface; a second arcuate surface located radially outward of the first arcuate surface; a third side surface extending radially outwardly in a first direction from a first end of the first arcuate surface; a fourth side surface extending radially outwardly in a second direction to a first end of the second arcuate surface; a fifth side surface connecting the third side surface and the fourth side surface; a sixth side surface extending radially outwardly from the second end of the first arcuate surface along a third direction; a seventh side surface extending radially outwardly along a fourth direction to a second end of the second arcuate surface; and an eighth side surface connecting the sixth side surface and the seventh side surface, Wherein, the first, second, third and fourth directions are different from each other.

4. The axial flux motor according to claim 3, wherein: The fifth side surface is perpendicular to both the third side surface and the fourth side surface.

5. The axial flux motor according to claim 3, wherein: The eighth side surface is perpendicular to both the sixth side surface and the seventh side surface.

6. The axial flux electric machine according to claim 3, wherein: The fifth side surface forms an oblique angle with the third and fourth side surfaces; and The eighth side surface forms an oblique angle with the sixth and seventh side surfaces.

7. An axial flux motor, comprising: A stator having a first side and a second side opposite the first side, the stator comprising: N stator core components on the first side, Wherein N is an integer greater than 2; and pole shoes attached to sides of the N stator core components; N slot openings between adjacent ones of the pole shoes; and a rotor comprising a third side and M permanent magnets on the third side, wherein the first side is parallel to the third side, and Where M is an integer greater than 2, and Wherein, each of the M permanent magnets comprises: a first arcuate surface; a second arcuate surface located radially outward of the first arcuate surface; and At least one of the following: a third side surface connecting first ends of the first arcuate surface and the second arcuate surface and extending non-radially in at least one direction on the third side of the rotor; and A fourth side surface connects the first arcuate surface and the second arcuate surface at second ends and extends non-radially in at least one direction on a third side of the rotor.

8. The axial flux motor according to claim 7, wherein: Each of the M permanent magnets includes both of: a third side surface connecting first ends of the first arcuate surface and the second arcuate surface and extending non-radially in at least one direction on the third side of the rotor; and A fourth side surface connects the second ends of the first arcuate surface and the second arcuate surface and extends non-radially in at least one direction on the third side of the rotor.

9. An axial flux motor, comprising: A stator having a first side and a second side opposite the first side, the stator comprising: N stator core components on the first side, Wherein N is an integer greater than 2; and pole shoes attached to sides of the N stator core components; N slot openings between adjacent ones of the pole shoes; and a rotor comprising a third side and M permanent magnets on the third side, wherein the first side is parallel to the third side, and Where M is an integer greater than 2, and Wherein, each of the M permanent magnets comprises: a first arcuate surface; a second arcuate surface located radially outward of the first arcuate surface; a third side surface extending radially outwardly in a first direction from a first end of the first arcuate surface; a fourth side surface extending radially outwardly in a second direction to a first end of the second arcuate surface; a fifth side surface connecting the third side surface and the fourth side surface; a sixth side surface extending radially outwardly from the second end of the first arcuate surface along a third direction; a seventh side surface extending radially outwardly along a fourth direction to a second end of the second arcuate surface; and an eighth surface connecting the sixth side surface and the seventh side surface, Wherein, the first, second, third and fourth directions are different from each other.

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