Electrical machinery

Abstract

The electric machine may have a plurality of trapezoidal teeth, each of which may have a substantially constant cross-sectional perimeter in the radial direction and a cross-sectional area that varies in the radial direction, and each of which may be formed from a plurality of members that, when combined with one another, form the trapezoidal tooth.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application is a continuation-in-part of U.S. patent application Ser. No. 18 / 382,583, filed October 23, 2023, which is a continuation-in-part of U.S. patent application Ser. No. 18 / 104,426, filed February 1, 2023, which is a continuation-in-part of U.S. patent application Ser. No. 17 / 882,947 (now U.S. Patent No. 11,594,920), filed August 8, 2022, which is a continuation-in-part of U.S. patent application Ser. No. 11,594,920, filed October 4, 2021. This application is a continuation of Application No. 17,493,089 (now U.S. Patent No. 11,451,099), which claims priority to International Application No. PCT / IB2021 / 058475, filed September 17, 2021, which claims priority to U.S. Provisional Patent Application No. 63 / 081,043, filed September 21, 2020, each of which is incorporated by reference herein in its entirety.

[0002] The present disclosure relates to electric machines, and in particular to radial flux electric machines. [Background technology]

[0003] The term "electric machine" (or electrical machine) generally refers to a machine whose operation relies on electromagnetic forces. The two main components of an electric machine can be described in mechanical or electrical terms. From a mechanical perspective, the rotor is the rotating component, and the stator is the stationary component of the electric machine. From an electrical perspective, the armature is the power-producing component, and the field is the magnetic field-producing component of the electric machine. The armature may be on the rotor or the stator, and the magnetic field may be provided by either electromagnets or permanent magnets attached to either the rotor or the stator. Electric machines are electromechanical energy converters and include, among others, electric motors and generators. Electric motors convert electricity into mechanical power, while generators convert mechanical power into electricity. The moving parts of an electric machine may be rotating (rotary electric machines) or linear (linear electric machines). Electric machines operate on the principle that electric current generates electromagnetic flux, and vice versa. In some electric machines, a rotor containing permanent magnets is configured to rotate in an electromagnetic field generated by multiple electromagnets through which electricity is passed.

[0004] Electric machines can be classified as axial-flux electric machines and radial-flux electric machines. The fundamental difference between these types of machines lies in the orientation of the magnetic field. In radial-flux electric machines, the working magnetic flux traverses the air gap between the stator and rotor in the radial plane, while in axial-flux electric machines, the magnetic flux traverses the air gap parallel to the axis of rotation. Many solutions are known that aim to reduce the stray magnetic fields of the electric machine's windings and permanent magnets and to increase the concentration of magnetic flux density in the stator and rotor cores, striving to ensure that the magnetic flux density value is the same in all parts of the core. There are also many solutions that aim to provide a high fill factor for permanent magnet electric machines. Some of these solutions use complex tooth shapes to improve electric machine performance. Some of these solutions effectively use tooth volume, but do not sufficiently reduce the electric machine's leakage flux. Additionally, in some cases, complex tooth shapes make it difficult to provide a high winding fill factor. The electric machines of the present disclosure alleviate some or all of the above-mentioned problems. The reduced leakage flux and increased fill factor in embodiments of the electric machines of the present disclosure may enable increased power and efficiency of the electric machine. However, the scope of the present disclosure is defined by the claims, not by the ability to solve any particular problem. Summary of the Invention

[0005] Several embodiments of electric machines and methods of making and using electric machines are disclosed. It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only. Therefore, the scope of the disclosure is not limited to the disclosed embodiments. Instead, it is intended to cover all such alternatives, modifications, and equivalents within the spirit and scope of the disclosed embodiments. Those skilled in the art will recognize that various changes, substitutions, and alterations to the disclosed embodiments can be made without departing from the spirit and scope of the disclosure.

[0006] Some disclosed embodiments include an electric machine having a plurality of coils and a plurality of U-shaped clips. Each coil of the plurality of coils may define a coil opening, and each U-shaped clip may include a first tooth, a second tooth, and a yoke interconnecting the first tooth and the second tooth. The first tooth of each U-shaped clip may be disposed within the coil opening of one of the plurality of coils, and the second tooth of each U-shaped clip may be disposed within the coil opening of another adjacent coil, and the yoke may bridge two adjacent coils. Two sidewalls of the two adjacent coils may be sandwiched between the first tooth and the second tooth of each U-shaped clip.

[0007] Some disclosed embodiments include an electric machine having a plurality of coils, at least one first yoke, at least one second yoke, and at least one intermediate yoke between the at least one first yoke and the at least one second yoke. Each coil may define a coil opening, and each coil opening may include a first section, a second section, and an intermediate section between the first section and the second section. A plurality of first wedge-shaped teeth may be integrally formed with and extend from the at least one first yoke, and each of the plurality of first wedge-shaped teeth may extend within the first section into a different one of the plurality of coil openings. A plurality of second wedge-shaped teeth may be integrally formed with and extend from the at least one second yoke, and each of the plurality of second wedge-shaped teeth may extend within the second section into a different one of the plurality of coil openings. A plurality of intermediate wedge-shaped teeth may be integrally formed with and extend from the at least one intermediate yoke, and the plurality of intermediate wedge-shaped teeth may extend within an intermediate section thereof into different ones of the plurality of coil openings.

[0008] Some disclosed embodiments include an electric machine having a plurality of electromagnetic coils, each of which defines a trapezoidally shaped, tapered coil opening. The plurality of electromagnetic coils may be arranged circumferentially about an axis of rotation of the electric machine. The electric machine may also include a plurality of yokes, each of which extends axially. At least one of the plurality of yokes may be tapered in the axial direction. The electric machine may also include a plurality of teeth. At least one tooth of the plurality of teeth may extend from each of the plurality of yokes. Each of the plurality of teeth may be radially tapered to enable the plurality of teeth to fit within a corresponding trapezoidally shaped, tapered coil opening.

[0009] Some disclosed embodiments include an air-coolable electric machine having a rotor, a stator, and a heat dissipation plate. The heat dissipation plate may have a first side disposed in thermal communication with the stator, a central opening, and an outer periphery. A plurality of circumferentially distributed Y-shaped or ψ-shaped cooling fins may extend from a second side of the heat dissipation plate opposite the first side. Each cooling fin may include a radially extending leg portion and a V-shaped or ψ-shaped deflector portion. Each V-shaped or ψ-shaped deflector portion may face the outer periphery of the heat dissipation plate to deflect a first portion of an airflow outward. Each radially extending leg portion may be positioned to direct a portion of the airflow inward toward the central opening.

[0010] The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the scope of the claims. [Brief explanation of the drawings]

[0011] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. In the drawings, where appropriate, reference numerals illustrating like structures, components, materials, and / or elements in different views are similarly numbered. It is understood that various combinations of structures, components, and / or elements other than those specifically shown are contemplated and within the scope of the present disclosure.

[0012] For simplicity and clarity of illustration, the figures depict the general structure of the various described embodiments. Details of well-known components or features may be omitted to avoid obscuring other features because these omitted features are well-known to those of ordinary skill in the art. Additionally, elements in the figures are not necessarily drawn to scale. To improve understanding of exemplary embodiments, the dimensions of some features may be exaggerated relative to other features. Those skilled in the art will appreciate that features in the figures are not necessarily drawn to scale and should not be considered to represent proportional relationships between different features in the figures unless otherwise indicated. Additionally, aspects described with reference to one embodiment or figure may be applicable to and used in conjunction with other embodiments or figures, even if not specifically mentioned.

[0013] [Figure 1] 1 illustrates a perspective view of one embodiment of an exemplary electric machine according to some embodiments of the present disclosure.

[0014] [Figure 2A] 2 is a cross-sectional view in an axial plane of the electric machine of FIG. 1;

[0015] [Figure 2B] 2 is a cross-sectional view in a radial plane of the electric machine of FIG. 1;

[0016] [Figure 2C] FIG. 2 is a cross-sectional view of another exemplary electric machine of the present disclosure in an axial plane.

[0017] [Figure 2D] 2D is a cross-sectional view in a radial plane of the electric machine of FIG. 2C.

[0018] [Figure 3A] 1 is a schematic diagram in an axial plane of a portion of an electric machine according to some embodiments of the present disclosure. [Figure 3B] 1 is a schematic diagram in an axial plane of a portion of an electric machine according to some embodiments of the present disclosure. [Figure 3C] 1 is a schematic diagram in an axial plane of a portion of an electric machine according to some embodiments of the present disclosure.

[0019] [Figure 4A] 1 is a perspective view of an exemplary tooth of an internal rotor electric machine according to some embodiments of the present disclosure.

[0020] [Figure 4B] FIG. 10 is a perspective view of another exemplary tooth of an external rotor electric machine according to some embodiments of the present disclosure.

[0021] [Figure 5A] 1A-1C illustrate cross-sectional views of an exemplary tooth in different planes according to some embodiments of the present disclosure. [Figure 5B] 1A-1C illustrate cross-sectional views of an exemplary tooth in different planes according to some embodiments of the present disclosure. [Figure 5C] 1A-1C illustrate cross-sectional views of an exemplary tooth in different planes according to some embodiments of the present disclosure. [Figure 5D] 1A-1C illustrate cross-sectional views of an exemplary tooth in different planes according to some embodiments of the present disclosure.

[0022] [Figure 6A] 1A-1C illustrate cross-sectional views of an exemplary tooth in different planes according to some embodiments of the present disclosure. [Figure 6B]1A-1C illustrate cross-sectional views of an exemplary tooth in different planes according to some embodiments of the present disclosure. [Figure 6C] 1A-1C illustrate cross-sectional views of an exemplary tooth in different planes according to some embodiments of the present disclosure. [Figure 6D] 1A-1C illustrate cross-sectional views of an exemplary tooth in different planes according to some embodiments of the present disclosure.

[0023] [Figure 7A] 1 illustrates various geometric features of an exemplary tooth according to some embodiments of the present disclosure. [Figure 7B] 1 illustrates various geometric features of an exemplary tooth according to some embodiments of the present disclosure.

[0024] [Figure 8] 1 illustrates an exemplary stator of an electric machine according to some embodiments of the present disclosure.

[0025] [Figure 9A] 1A-1C illustrate several different views of an exemplary electromagnetic coil of an electric machine according to some embodiments of the present disclosure. [Figure 9B] 1A-1C illustrate several different views of an exemplary electromagnetic coil of an electric machine according to some embodiments of the present disclosure. [Figure 9C] 1A-1C illustrate several different views of an exemplary electromagnetic coil of an electric machine according to some embodiments of the present disclosure.

[0026] [Figure 10A] 1 is a perspective view of an exemplary multi-component tine of an electric machine according to some embodiments of the present disclosure. [Figure 10B] 1 is a perspective view of an exemplary multi-component tine of an electric machine according to some embodiments of the present disclosure.

[0027] [Figure 11A] 1A-1C are diagrams of exemplary portions of a multi-piece tooth according to some embodiments of the present disclosure. [Figure 11B] 1A-1C are diagrams of exemplary portions of a multi-piece tooth according to some embodiments of the present disclosure. [Figure 11C] 1A-1C are diagrams of exemplary portions of a multi-piece tooth according to some embodiments of the present disclosure. [Figure 11D] 1A-1C are diagrams of exemplary portions of a multi-piece tooth according to some embodiments of the present disclosure. [Figure 11E] 1A-1C are diagrams of exemplary portions of a multi-piece tooth according to some embodiments of the present disclosure. [Figure 11F] 1A-1C are diagrams of exemplary portions of a multi-piece tooth according to some embodiments of the present disclosure.

[0028] [Figure 12A] 10A-10C are diagrams of other exemplary portions of a multi-piece dental arrangement according to some embodiments of the present disclosure. [Figure 12B] 10A-10C are diagrams of other exemplary portions of a multi-piece dental arrangement according to some embodiments of the present disclosure. [Figure 12C] 10A-10C are diagrams of other exemplary portions of a multi-piece dental arrangement according to some embodiments of the present disclosure. [Figure 12D] 10A-10C are diagrams of other exemplary portions of a multi-piece dental arrangement according to some embodiments of the present disclosure.

[0029] [Figure 13A] 1 is a schematic diagram of another exemplary multi-component tooth of an electric machine according to some embodiments of the present disclosure. [Figure 13B] 1 is a schematic diagram of another exemplary multi-component tooth of an electric machine according to some embodiments of the present disclosure.

[0030] [Figure 14A] 1 is a cross-sectional perspective view of another exemplary multi-component teeth arrangement of an electric machine according to some embodiments of the present disclosure. [Figure 14B] 1 is a cross-sectional perspective view of another exemplary multi-component teeth arrangement of an electric machine according to some embodiments of the present disclosure.

[0031] [Figure 15A] 10 is a schematic diagram of a further exemplary multi-component teeth arrangement of an electric machine according to some embodiments of the present disclosure. [Figure 15B]10 is a schematic diagram of a further exemplary multi-component teeth arrangement of an electric machine according to some embodiments of the present disclosure. [Figure 15C] 10 is a schematic diagram of a further exemplary multi-component teeth arrangement of an electric machine according to some embodiments of the present disclosure.

[0032] [Figure 16A] 1A-1C illustrate several different views of a portion of an exemplary electric machine according to some embodiments of the present disclosure. [Figure 16B] 1A-1C illustrate several different views of a portion of an exemplary electric machine according to some embodiments of the present disclosure.

[0033] [Figure 17A] 1 illustrates an exemplary multi-piece tooth component according to some embodiments of the present disclosure. [Figure 17B] 1 illustrates an exemplary multi-piece tooth component according to some embodiments of the present disclosure. [Figure 17C] 1 illustrates an exemplary multi-piece tooth component according to some embodiments of the present disclosure.

[0034] [Figure 18A] 1 illustrates an exemplary multi-piece tooth assembly according to some embodiments of the present disclosure. [Figure 18B] 1 illustrates an exemplary multi-piece tooth assembly according to some embodiments of the present disclosure.

[0035] [Figure 19] 1 illustrates a perspective view of an exemplary electric machine according to some embodiments of the present disclosure.

[0036] [Figure 20A] 1 is a diagram of an exemplary heat dissipation plate of an electric machine according to some embodiments of the present disclosure. [Figure 20B] 1 is a diagram of an exemplary heat dissipation plate of an electric machine according to some embodiments of the present disclosure. [Figure 20C] 1 is a diagram of an exemplary heat dissipation plate of an electric machine according to some embodiments of the present disclosure.

[0037] [Figure 21A] 1 illustrates an exemplary shape of a cooling fin according to some embodiments of the present disclosure. [Figure 21B] 1 illustrates an exemplary shape of a cooling fin according to some embodiments of the present disclosure.

[0038] [Figure 22] 1 illustrates a cross-sectional perspective view of another exemplary heat dissipation plate of an electric machine according to some embodiments of the present disclosure.

[0039] [Figure 23A] 10A-10C depict an exemplary method of assembling a stator according to some embodiments of the present disclosure. [Figure 23B] 10A-10C depict an exemplary method of assembling a stator according to some embodiments of the present disclosure. [Figure 23C] 10A-10C depict an exemplary method of assembling a stator according to some embodiments of the present disclosure. [Figure 23D] 10A-10C depict an exemplary method of assembling a stator according to some embodiments of the present disclosure. [Figure 23E] 10A-10C depict an exemplary method of assembling a stator according to some embodiments of the present disclosure. [Figure 23F] 10A-10C depict an exemplary method of assembling a stator according to some embodiments of the present disclosure. [Figure 23G] 10A-10C depict an exemplary method of assembling a stator according to some embodiments of the present disclosure. [Figure 23H] 10A-10C depict an exemplary method of assembling a stator according to some embodiments of the present disclosure. [Figure 23I] 10A-10C depict an exemplary method of assembling a stator according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0040] With respect to the terminology used in this detailed description, all relative terms such as "about," "substantially," "approximately," etc. are used to indicate a possible variation of up to 15% (unless otherwise stated or another variation is specified). For example, a cross-sectional area of ​​a first region described in this disclosure as being substantially equal to or substantially the same as the cross-sectional area of ​​a second region encompasses a variation in cross-sectional area of ​​up to 15% within that range. Similarly, a dimension substantially equal to a "t" unit (width, length, etc.) encompasses a variation of up to 15%. Additionally, dimensions described as being between a range (e.g., XY, X to Y, etc.) include the two boundaries. That is, the dimension between X and Y can be any dimension between X - 15(%) and X + 15(%). Unless otherwise specified, all terms relating to the shape of an object or area refer to an approximate shape. For example, a cross-sectional shape described as being rectangular (rectangular, trapezoidal, etc.) does not necessarily refer to an exact rectangle (unless so described). Instead, slight variations in the described shapes (e.g., due to manufacturing processes, tolerances, etc.) are also encompassed. For example, corners of a cross-sectional area described as square may have rounded (or chamfered) corners, corner angles may vary by up to 15%, parallelism between opposing sides may vary by 15%, etc.

[0041] Unless otherwise defined, all technical terms, notations, and other scientific or technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Some of the components, structures, and / or processes described or referred to herein are well understood by those skilled in the art and commonly employed using conventional methodologies. Therefore, these components, structures, and processes will not be described in detail. All patents, applications, published applications, and other publications referred to herein are incorporated by reference in their entirety. If a definition or explanation set forth in this disclosure contradicts or otherwise contradicts the definitions and / or explanations in these references, the definition and / or explanation set forth in this disclosure shall take precedence over those in the references incorporated by reference. None of the references described or referred to herein are admitted as prior art to the present disclosure.

[0042] Various embodiments of the present disclosure involve electric machines. As used herein, an "electric machine" (or electric machine) is a device that operates based on electromagnetic forces. An electric machine may be an energy converter that converts electrical energy into mechanical energy or vice versa. In other words, some electric machines convert electrical energy into mechanical energy, and some electric machines convert mechanical energy into electrical energy. In general, any type of electromechanical energy converter that runs on or generates electricity is an electric machine. In some embodiments, the electric machine may be an electric motor or generator. During operation, the electric machine generates magnetic flux. In a radial-flux electric machine, at least some portion of the generated magnetic flux extends perpendicular to the axis of rotation of the machine. The electric machine includes a stator and a rotor separated by an air gap. In a radial-flux electric machine, the working (or main) magnetic flux may extend between the rotor and the stator through the air gap in the radial plane.

[0043] FIG. 1 illustrates an exemplary electric machine 10. In some embodiments, the electric machine 10 may be a radial-flux electric machine. In general, electric machines may be air-cooled or liquid-cooled. The electric machine 10 illustrated in FIG. 1 may be an air-cooled system having a housing 12. External ribs 14 may be positioned on an exterior surface of the housing 12 to transfer heat generated by the electric machine 10 to the surrounding air during operation. The following discussion describes the electric machine 10 in the form of an electric motor. However, this description is equally applicable to other types of electric machines, such as, for example, a generator. When the electric machine 10 operates, its shaft 16 rotates about an axis of rotation 20. The electric machine 10 may include a stator and a rotor. As used herein, a "stator" refers to a stationary or fixed part, component, or assembly (of components) of an electric machine, and a "rotor" refers to a part, component, or assembly configured to move relative to the stator. In other words, the rotor may be the rotating part and the stator may be the stationary part of the electric machine. The rotor may be positioned radially inward of the stator (referred to as an inner rotor electric machine) or radially outward of the stator (referred to as an outer rotor electric machine). The present disclosure is applicable to both inner rotor and outer rotor machines.

[0044] FIG. 2A is a cross-sectional view of an exemplary outer-rotor electric machine 10 taken along an axial plane 22 of the machine 10, and FIG. 2B is a cross-sectional view of the machine 10 taken along a radial plane 24 of the machine 10. FIG. 2C is a cross-sectional view of an exemplary inner-rotor electric machine 10A taken along an axial plane 22 of the machine. As used herein, "axial plane" refers to an imaginary plane in which the axis of rotation 20 lies. In other words, every point on the axis of rotation 20 of the electric machine 10 lies within the axial plane 22. As seen in FIGS. 2A and 2C, the axis of rotation 20 of the machine lies within the axial plane 22, which bisects the electric machine into two symmetrical halves. "Radial plane" refers to an imaginary plane that extends perpendicular to the axis of rotation 20. In some embodiments, the electric machine may have a generally cylindrical configuration (see, e.g., FIG. 1 ), and the radial plane 24 may be a plane used to describe an imaginary slice along the radial axis 90 of the generally cylindrically shaped machine. In other words, every point on the radial axis 90 lies within the radial plane 24. The axial plane 22 and the radial plane 24 are mutually orthogonal, or perpendicular, planes. In FIG. 2B , the rotational axis 20 extends perpendicular to the radial plane 24 (e.g., into and out of the page). The electric machine 10 of FIG. 2A includes a stator 30 positioned radially inward of the rotor 40, while in the electric machine 10A of FIG. 2C , the rotor 40 is positioned radially inward of the stator 30. In the electric machines 10 and 10A, the rotor 40 may be configured to rotate about a rotational axis 20 relative to the stator 30. The rotor 40 may be connected to a shaft 16 configured to rotate about the rotational axis 20. In some embodiments, rotor 40 may be coupled to shaft 16 so that the rotor and shaft rotate about axis of rotation 20 without relative motion between them.

[0045] The rotor of the disclosed electric machine may include multiple permanent magnets in some embodiments. A "permanent magnet" is a magnet formed from a material that generates its own magnetic field due to its internal structure without an external magnetizing field. In other words, a permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. For example, the internal structure of a permanent magnet may create a persistent magnetic field within it, so that it still retains its own magnetic field even after the external magnetizing field is removed. The rotor's permanent magnets generate a flux field within the rotor. During operation of the electric machine, the stator generates a field that interacts with the rotor's magnetic field. Changing the position of the stator field relative to the rotor field causes the rotor to shift. The shift resulting from this interaction is magnetic torque. Any type of permanent magnet may be used. In some embodiments, the permanent magnets may include one or more of ferrite, alnico, samarium-cobalt, or neodymium alloys. Referring to the electric machine 10 of FIGS. 2A and 2B , multiple permanent magnets 60 are coupled to a rotor core 64 of the rotor 40. As best seen in FIG. 2B , each permanent magnet 60 may include multiple permanent magnet segments 62 connected to one another in the form of an arc around the axis of rotation 20. Generally, any number of magnet segments 62 may be included in each permanent magnet 60. In some embodiments, all permanent magnets 60 may include the same number of segments 62. In some embodiments, multiple segments 62 may be attached to one another (e.g., with an adhesive material) to form the permanent magnet 60. In some embodiments, each permanent magnet 60 may be coated with an electrically non-conductive material. In some embodiments, adjacent permanent magnets 60 may be separated from one another by spacers 66 made of an electrically non-conductive material. The spacers 66 may be attached to adjacent permanent magnets 60 with an adhesive material (e.g., glue). In some embodiments, the spacers 66 may be eliminated, and adjacent permanent magnets 60 may be separated from one another by spaces or gaps.

[0046] The stator (and / or rotor) of an electric machine may include a plurality of teeth. As used herein, "teeth" (and its singular form "tooth") refers to a protrusion or projection. For example, as used herein, tooth generally refers to any protrusion or projection. In a radial-flux electric machine, the teeth may protrude or extend radially toward or away from the axis of rotation of the machine. In other words, the teeth may be projections that protrude along the radial axis of the machine (e.g., toward or away from the axis of rotation). In some embodiments, at least a portion of the teeth may protrude from the body. The portion of the teeth that protrude from the body may be integral with the body or connected (or coupled) to the body. Although the teeth may be part of the stator or rotor, in the following discussion, the teeth are described as being part of the stator. For example, in the exemplary outer-rotor electric machine 10 of FIG. 2A , teeth may project radially from the stator 30 toward the rotor 40, away from the rotational axis 20, while in the exemplary inner-rotor electric machine 10A of FIG. 2C , teeth may project radially from the stator 30 toward the rotor 40, toward the rotational axis 20. In some embodiments, the stator teeth may include a series of substantially similar protrusions projecting from a body. Each protrusion may form a tooth or a portion of a tooth. The teeth may be configured or shaped so that a majority of the magnetic flux is directed between the stator and the rotor. Referring to FIGS. 2A and 2B , in the electric machine 10, the stator 30 includes a plurality of teeth 50 arranged annularly and symmetrically about the rotational axis 20. The teeth 50 extend radially outward from a stator core 52 that extends around the rotational axis 20. As previously described, in the inner-rotor electric machine 10A, the stator teeth 50 may project radially inward toward the rotational axis 20. In Figure 2B, dashed lines are used to indicate the outline of tooth 50. As can be seen in Figures 2B and 2C, in some embodiments, each tooth 50 may include multiple members or parts arranged together to form a composite or multi-part tooth. It should be noted that the configuration of multi-part tooth 50 shown in Figures 2B and 2C is exemplary only, and many variations are possible.As will be described in more detail below, in some embodiments of the present disclosure, each tooth 50 may be a multi-piece tooth and may have a trapezoidal cross-sectional shape in both the axial plane (see FIGS. 2A and 2C) and the radial plane (see FIG. 2B).

[0047] An electric machine of the present disclosure may include multiple electromagnetic coils. An “electromagnetic coil” (which may be simply referred to herein as a coil) may include one or more turns of an electrical conductor (e.g., a wire, multiple strands twisted together, a strip, a foil, or another configuration of an electrical conductor) that generates a magnetic field when an electric current is passed through the conductor (e.g., in an electric motor) or generates a voltage across the conductor when a magnetic field is passed over the coil. In some embodiments, the turns of an electrical conductor may have a configuration or shape such as a coil, loop, twist, curl, or spiral. In some embodiments, an electromagnetic coil may be an electrical conductor including a series of conductive wires configured to be wound around a ferromagnetic core. In general, electromagnetic coils of the present disclosure may be associated with the stator or rotor of an electric machine. That is, in some embodiments, multiple coils may be coupled to the rotor (e.g., mounted, located, wound, etc. on the rotor), while in other embodiments, multiple coils may be coupled to the stator. 2A-2C, a plurality of electromagnetic coils 70 are coupled to the stator 30 such that each electromagnetic coil 70 is mounted on a multi-piece tooth 50 of the stator 30. In some embodiments, each coil 70 may be tightly fitted or mounted on a tooth 50 such that the inner surface of the coil 70 is in physical contact with the outer surface of the multi-piece tooth 50.

[0048] In the exemplary embodiment of the electric machine 10 shown in FIG. 2B , the stator 30 includes nine multi-piece teeth 50 and the rotor 40 includes ten permanent magnets 60. However, this is merely exemplary, and in general, any number of teeth and permanent magnets may be provided. In the electric machine 10 discussed with reference to FIGS. 2A and 2B , the rotor 40 is positioned radially outward (or external) of the stator 30, and the stator and rotor are separated by a single air gap 80. In this embodiment, the width (W) of each multi-piece tooth 50 in the radial plane 24 increases radially outward along the radial axis 90 toward the air gap 80 (and rotor 40) (see FIG. 2B ), and the length (l) of each tooth 50 in the axial plane 22 decreases radially outward along the radial axis 90 toward the air gap 80 (see FIG. 2A ). This is also exemplary, and electric machines of the present disclosure may have other configurations. For example, Figures 3A-3D are schematic diagrams of several exemplary configurations of electric machines of the present disclosure, showing the layout of a stator 30 relative to a rotor 40. In each case, the rotor 40 includes a plurality of permanent magnets 60 and is connected to a shaft that rotates about a rotational axis 20. The stator 30 also includes a plurality of teeth 50 arranged in an annular pattern about the rotational axis 20, with an electromagnetic coil 70 mounted on each tooth 50. As with the embodiment of Figures 2A-2C, each tooth 50 in the electric machines of Figures 3A-3C may include multiple pieces (e.g., each tooth is a multi-piece tooth), and each multi-piece tooth 50 may have a trapezoidal cross-sectional shape in both the axial and radial planes.

[0049] In the electric machine 10A of FIGS. 2C and 3A, the rotor 40 is positioned radially inward (e.g., inner rotor) of the stator 30, and they are separated by an air gap 80. In the electric machine 10A, the length (l) of each tooth 50 in the axial plane increases radially inward toward the air gap 80 and rotor 40, and the tooth width in the radial plane decreases radially inward toward the air gap 80 and rotor 40. Note that, although not visible in FIGS. 2C and 3A, the radial plane extends into the plane of the paper. The electric machine 10B of FIG. 3B includes two stators 30A, 30B positioned on opposite sides of the rotor 40. Both the inner stator 30A and the outer stator 30B include a plurality of multi-component teeth 50A, 50B arranged annularly about the axis of rotation 20. In the electric machine 10B, the width of each tooth 50A (in the radial plane) of the inner stator 30A increases radially outward toward the rotor 40 and air gap 80A, while the width of each tooth 50B of the outer stator 30B decreases radially inward toward the rotor 40 and air gap 80B. Conversely, as shown in FIG. 3B , the length of each tooth 50A (in the axial plane) of the inner stator 30A decreases radially outward toward the rotor 40 and air gap 80A, while the length of each tooth 50B of the outer stator 30B increases radially inward toward the rotor 40 and air gap 80B. In other words, when the width of a tooth 50 decreases in one direction, its length increases in the same direction, and vice versa. The electric machine 10C of FIG. 3C includes two rotors 40A, 40B positioned on opposite sides of the stator 30. An air gap 80A is formed between the inner rotor 40A and the stator 30, and an air gap 80B is formed between the outer rotor 40B and the stator 30. Such an electric machine may be referred to as a double-gap machine. Similar to the previously discussed electric machines, the stator 30 of the electric machine 10C includes a plurality of multi-piece teeth 50. The width of each tooth 50 (in the radial plane) increases radially outward toward the outer rotor 40B and air gap 80B and decreases radially inward toward the inner rotor 40A and air gap 80A.Conversely, as shown in FIG. 8C, the length of each tooth 50 (in the axial plane) decreases radially outward toward the outer rotor 40B and air gap 80B and increases radially inward toward the inner rotor 40A and air gap 80A.

[0050] Electric machines of the present disclosure may have other configurations. See, for example, FIGS. 8A-22 of WO 2022 / 058939 A1 (published March 24, 2022), the entire contents of which are incorporated herein by reference. As previously described, electric machines of the present disclosure may include teeth with multiple parts that, when arranged together, have a trapezoidal cross-sectional shape in both the axial plane 22 and the radial plane 24. Additionally, electromagnetic coils may be mounted on one or more (e.g., all) of the multi-part teeth. While the teeth are described as being part of the stator in the exemplary embodiments discussed above, this is merely exemplary. In general, the multi-part teeth may be part of the stator and / or rotor.

[0051] In the electric machine of the present disclosure, each multi-component tooth may have a trapezoidal cross-sectional shape in two mutually perpendicular planes (i.e., the axial and radial planes). That is, as previously described with reference to FIGS. 2A and 2B , the cross-sectional shape of each tooth 50 in the axial plane 22 and the radial plane 24 may be trapezoidal. As used in this disclosure, a “trapezoid” is a two-dimensional, flat, closed shape having four substantially straight sides with only one pair of parallel sides. Note that in an actual tooth, some or all sides of the tooth may deviate from being perfectly straight, and some or all corners of the tooth (e.g., between the sides) may deviate from being sharp (e.g., rounded or beveled), for example, due to manufacturing and tolerance requirements. For example, in some embodiments, opposite sides of a tooth cross-section may not be perfectly parallel, adjacent sides may not be perfectly perpendicular, and corners may be rounded and / or chamfered. In some embodiments, the cross-sectional shape of the tooth in the axial and / or radial planes may be an isosceles trapezoid (i.e., a trapezoid with opposite sides of equal length). FIG. 4A shows a perspective view of an exemplary multi-component tooth 50 of an internal rotor electric machine after the multiple components that make up the tooth have been assembled together. FIG. 4B shows an exemplary multi-component tooth 50 of an external rotor electric machine. FIGS. 4A and 4B show only the outer boundary of the assembled tooth, not the boundaries of the different components of the tooth. The width and length of each tooth 50 vary along the radial axis 90. For example, the length of the tooth 50 varies radially outward (from the axis of rotation 20) along the radial axis 90 from l1 to l2, and the width of the tooth 50 varies radially outward along the radial axis 90 from w1 to w2.

[0052] 5A-5D are cross-sectional images of a multi-piece tooth 50 along several different planes. FIG. 5A shows a cross-sectional image of the tooth 50 in the axial plane 22 (compare FIG. 2A). In FIG. 5A, the tooth 50 is indicated by hatching. As can be seen from FIG. 5A, the cross-sectional shape of the tooth 50 in the axial plane 22 is a trapezoid (i.e., a rectangle with one pair of opposing parallel sides and another pair of opposing non-parallel sides). In some embodiments, the cross-sectional shape of the tooth 50 in the axial plane 22 may be an isosceles trapezoid. As can be seen from FIG. 5A, the length of the tooth 50 decreases as the radial distance increases along the radial axis 90. FIGS. 5B-5D show cross-sections of the tooth 50 in several different planes (AA, BB, and CC) perpendicular to the radial direction 90. FIG. 5B is a cross-sectional view of tooth 50 taken along plane AA, FIG. 5C is a cross-sectional view of tooth 60 taken along plane BB, and FIG. 5D is a cross-sectional view of tooth 60 taken along plane CC. As can be seen from FIGS. 5B-5D, tooth 50 may have a substantially rectangular cross-sectional shape in a plane perpendicular to radial direction 90. Note that FIGS. 5B-5D do not include right-angle corners (i.e., 90 oA complete rectangle with corners) is shown, but this is only exemplary. As previously explained, these cross-sectional shapes of the actual teeth 50 may not be perfect rectangles (see, for example, FIG. 4B). As shown in FIGS. 5B-5D, the rectangular shape becomes shorter and wider as the distance in the radial direction increases. That is, as the distance along the radial axis 90 increases from the rotational axis 20, the length of the tooth 50 decreases (i.e., a1>b1>c1 and a3>b3>c3), and the width of the tooth 120 increases (i.e., a2<b2<c2 and a4<b4<c4). Although not necessary, in some embodiments, the opposing sides of the cross-sectional shape may be equal. That is, (a1=a3)>(b1=b3)>(c1=c3) and (a2=a4)<(b2=b4)<(c2=c4). In other words, the tooth 50 gradually becomes shorter and wider in the radially outward direction from the rotational axis 20. The cross-sectional area of the tooth 50 (i.e., the cross-sectional area in a plane perpendicular to the radial axis 90) also varies in the radially outward direction. In some embodiments where the rotor 40 is outside the stator 30 (e.g., FIGS. 2A, 2B), the cross-sectional area may increase in the radially outward direction (i.e., S A <S B <S C ). In other embodiments of the electromechanical device, the area may vary in a different manner along the radial direction. For example, in an electromechanical device having an inner rotor 40 and an outer stator 3 (see FIG. 3A), the cross-sectional area may decrease in the radially outward direction along the radial axis 90 (i.e., increase in the radially inward direction).

[0053] Referring to FIGS. 5A-5D, the perimeter of each tooth 50 in the radial direction along the radial axis 90 may be substantially constant, while the cross-sectional area of each tooth 50 in the radial direction may vary. That is, the perimeters of the cross-sections of the tooth 50 along planes A-A, B-B, and C-C (see FIGS. 5B-5D) may be substantially the same, while the cross-sectional area thereof in these planes may not be constant (e.g., may vary). That is, (a1+a2+a3+a4)≒(b1+b2+b3+b4)≒(c1+c2+c3+c4), but S A ≠SB ≠S C In electric machines of the present disclosure, regardless of the configuration of the electric machine (e.g., inner rotor or outer rotor), the perimeter of each tooth (in a cross section perpendicular to radial axis 90) may remain substantially constant in the radial direction (e.g., along radial axis 90), while its cross-sectional area may vary in this direction. In embodiments where rotor 40 is outside stator 30 (FIGS. 2A-2B), the cross-sectional area of ​​each tooth 50 may increase in the radially outward direction (see FIGS. 26B-26D), and in embodiments where rotor 40 is inside stator 30 (FIG. 3A), the cross-sectional area of ​​each tooth 50 may increase in the radially inward direction.

[0054] 6A-6D are cross-sectional views of the tooth 50 along different planes. Similar to FIG. 5A, FIG. 6A shows a cross-sectional image of the tooth 50 in the axial plane 22. FIGS. 6B-6D show cross-sections of the tooth 50 along different parallel radial planes 24 (DD, EE, and FF) perpendicular to the rotation axis 20 along the axial direction of the tooth 50 (i.e., different parallel planes along the rotation axis 20). FIG. 6B is a cross-sectional view of the tooth 50 along plane DD, FIG. 6C is a cross-sectional view of the tooth 50 along plane EE, and FIG. 6D is a cross-sectional view of the tooth 50 along plane FF. As shown in these figures, the cross-sectional area of ​​the tooth 50 decreases axially from the center to the edge of the tooth. That is, S D >S E >S FIn other words, the cross-sectional area of ​​the tooth 50 in a plane perpendicular to the radial axis 90 (or perpendicular to the radial direction) varies radially (see FIGS. 5B-5D), and the cross-sectional area of ​​the tooth 50 in a plane perpendicular to the rotation axis 20 (or perpendicular to the axial direction, or parallel to the radial direction or axis 90) varies axially (see FIGS. 6B-6D). In some embodiments of electric machines with an outer rotor and an inner stator (e.g., FIGS. 2A and 2B), the cross-sectional area of ​​each tooth 50 increases radially outward (see FIGS. 5B-5D) and decreases axially outward (see FIGS. 6B-6D). Conversely, in some embodiments of electric machines with an inner rotor and an outer stator (e.g., FIG. 3A), the cross-sectional area of ​​each tooth decreases radially outward and increases axially outward.

[0055] 7A and 7B illustrate some geometric details of the exemplary tooth 50 of FIG. 4A. FIG. 7A is a cross-sectional view of the tooth 50 in a radial plane, and FIG. 7B is a perspective view (looking down on the tooth) of the tooth 50. As previously explained, each tooth 50 widens (in the radial plane) as it extends radially outward along a radial axis 90 (see, for example, FIGS. 4A and 4B). As shown in FIG. 7A, opposing sides C and D of the tooth 50 form an angle γ with the radial axis 90. The value of angle γ may depend on the number of teeth 50 in the electric machine. Generally, angle 2γ (the angle between opposing sides C and D of the tooth 50) may be approximately equal to 360 degrees divided by the number of teeth 50. That is, 2γ≈360° / n, where n is the number of teeth. For example, for an electric machine 10 having nine teeth 50 (see FIG. 2B ), the angle 2γ≈360 / 9=40°. Thus, each side C, D of a tooth 50 may be angled approximately 20° (γ≈20°) from the radial axis 90. As described with reference to FIGS. 2A and 2B , an air gap 80 exists between the stator 30 and the rotor 40, defined between the radially outermost end of each tooth 50 and the rotor 40 (e.g., the permanent magnet segments 60 of the rotor 40). Generally, a coil 70 may be mounted on each tooth 50 such that the radially outermost end of the coil 70 is positioned as close as possible to the radially outermost end of the tooth 50 (and the air gap 80) without protruding into the air gap 80. In some embodiments, the tooth 50 may include a pole piece (not shown) at its radially outermost end. Typically, the radial distance between the radially outermost end of the coil 70 and the radially outermost end of the tooth 50 (shown as coincident in FIG. 7A ) may be less than or equal to about 20% of the thickness of the air gap 80. In some embodiments, as shown in FIG. 7A , the radially outermost ends of the teeth 50 may be rounded or curved, such that all of the teeth 50 together form a substantially circular profile. Referring to FIG. 7B , the leading and trailing faces of the teeth 50 may form an angle β with the axial plane 22 of the teeth 120. The angle β may also depend on the number of teeth in the electric machine.A tooth 50 having a substantially constant circumference in the radial direction along the radial axis 90 may result in the following correlations (see FIG. 7B): h1=d1; d1=r*Sin(γ); h1=r*Tan(β); ​​r*Sin(γ)=r*Tan(β); ​​Sin(γ)=Tan(β); ​​β=Arctan(Sin(γ)), ​​or β=1 / Tan(Sin(γ)).

[0056] 2A and 2B, when power is provided to the coils 70 of the stator 30, a magnetic field is generated. Based on the generated magnetic field, magnetic flux flows between the rotor 40 and the stator 30, which provides a rotational force to the rotor 40 and causes the coupled shaft 16 to turn (or rotate). The electric machine 10 may be used as a power source in any application, for example, in an electric vehicle, the electric machine 10 may drive the wheels of the electric vehicle.

[0057] As previously described, an electromagnetic coil 70 may be mounted on each multi-component tooth 50 of the electric machines 10, 10A, 10B, and 10C. Traditionally, the electrical conductor (e.g., copper wire, copper foil) used to form the coil 70 is tightly wound around the tooth to mount the coil on the tooth. However, winding wire around the tooth is laborious and time-consuming. One approach that may be used to increase efficiency and save time during the assembly process is to place a pre-wound or pre-fabricated coil around each tooth of the electric machine. A pre-wound coil may be prepared by winding copper wire around a removable coilform (e.g., a die) having a shape similar to the shape of the tooth to which the coil will be mounted, removing the coilform from the wound coil, and inserting the pre-wound coil onto the tooth (e.g., like a finger ring). To ensure a tight or close fit of the coil around the tooth, the cavity in the pre-wound coil may have a shape and size substantially the same as the shape and size of the tooth. Because the teeth of the electric machines of the present disclosure have a trapezoidal cross-sectional shape that is radially non-uniform (non-uniform trapezoidal cavity), when a pre-wound coil is inserted onto the tooth in a conventional manner, the coil may not fit tightly along the entire radial distance of the tooth.

[0058] Thus, in various embodiments of the present disclosure, each tooth may be formed from multiple pieces that, when assembled together, correspond to the shape of the non-uniform trapezoidal cavity of the coil 70. In other words, each tooth may be a multi-piece tooth. In general, each piece of a multi-piece tooth may have any size and shape. A multi-piece tooth may be formed from any number of pieces, and these multiple pieces may be assembled together in any manner. For example, in some embodiments, the multiple pieces may be assembled and glued together or attached to each other. In some embodiments, the multiple pieces may be placed loosely or tightly together without being attached to each other. In the following discussion, each piece of a multi-piece tooth may be referred to as a tooth.

[0059] According to some disclosed embodiments, an electric machine includes a plurality of coils, wherein each coil of the plurality of coils defines a coil opening. As previously explained, an electromagnetic coil (which may be referred to herein simply as a "coil") refers to one or more turns of an electrical conductor (e.g., a wire, multiple twisted strands, a strip, a foil, or another configuration of an electrical conductor). The one or more turns generate a magnetic field when a current is passed through the conductor (e.g., in an electric motor) or generate a voltage across the conductor when a magnetic field is passed over the coil. The term "coil opening" refers to an opening in a coil. For example, a coil may include a winding of an electrical conductor extending around a coil opening (or cavity) in the coil. The coil opening may extend from a first end at one end of the coil to a second end at the opposite end of the coil and may be open at both its first and second ends.

[0060] As described with reference to FIGS. 2A and 2B , the exemplary electric machine 10 of the present disclosure includes a plurality of coils 70. FIG. 8 illustrates a cross-sectional view of a portion of an exemplary internal-rotor electric machine 10D in which the stator 30 has been partially removed from the housing 12 (e.g., axially pulled along the axis of rotation 20) to reveal the plurality of coils 70 on the stator 30. Note that FIG. 8 does not show the rotor that would be positioned radially inward of the cylindrical stator 30. Each coil 70 may be mounted on a multi-component tooth 50 of the stator 30. As previously described, each multi-component tooth 50 of the electric machine 10A may be formed from multiple parts that, when combined together, form the tooth 50 on which the coil 70 is mounted. FIGS. 9A through 9C illustrate several different views of an exemplary coil 70 separated from the tooth of the stator 30. The coil 70 may include a winding of copper wire 72 (or another electrical conductor) extending from a first end 76 to a second end 78 around a coil opening 74 (or cavity). In some embodiments, the wire 72 may have one of a square, rectangular, or circular cross-sectional shape. In some embodiments, the coil 70 may include a winding of copper strands 72 in a helical configuration around the opening 74. In some embodiments, the coil 70 may include a winding of copper foil around the opening 74. When the coil 70 is mounted on a tooth (see, for example, FIGS. 2A and 2B ), the coil opening 74 extends along the radial axis 90, with the first end 76 positioned closer to the rotation axis 20 and the second end 78 positioned further away from the rotation axis 20. The coil opening 74 may generally have the same shape as the tooth 50. The size of the opening 74 may also be substantially the same as the size of the tooth 50. In some embodiments, the coil openings 74 may be sized slightly smaller than the teeth 50 so that the wire 72 forming the coil 70 stretches or expands when placed on the teeth 50 to closely receive the teeth within the coil openings 74. In some embodiments, similar to the shape of the teeth 50 (e.g., as previously described with reference to FIGS. 4-7B ), the openings 74 may have a trapezoidal three-dimensional shape with a rectangular cross-sectional area in a plane perpendicular to an axis extending between the first and second ends 76, 78 of the coil 70 (e.g., radial axis 90 when assembled on the teeth 50).

[0061] According to some disclosed embodiments, an electric machine includes a plurality of U-shaped clips. As used herein, the term “clip” simply refers to a component, part, or member that facilitates, at least to some extent, a holding, joining, and / or fastening function. While not required, in some embodiments, the clip may serve to hold one or more objects together (e.g., a minimal role, a minor role, a major role, a significant role, etc.). For example, in some embodiments, the clip may serve to hold one or more coils of a plurality of coils of an electric machine together. In some embodiments, the clip may not serve to hold the coils or any other components of the electric machine together. Instead, the clip may simply be part of the electric machine. In the following description, the clip may also be referred to as a spacer. As used herein, a “U-shaped” clip indicates that at least some portion of the clip (e.g., the entire clip or one or more portions of the clip) resembles a capital U (e.g., has an opening between two joined sides). For example, if the specific geometric details of the clip are ignored, the shape or configuration of one or more portions of the clip may generally resemble a U-shape. In some embodiments of a U-shaped clip, the entire clip may have a generally U-shape (see, e.g., FIGS. 11E, 12B-12D). Also, in some embodiments of a U-shaped clip, the clip may have multiple generally U-shaped regions (see, e.g., FIGS. 11A-11C). In some embodiments, these U-shaped clips may form at least a portion of a multi-component tooth of an electric machine. For example, in some embodiments, multiple U-shaped clips may collectively form a multi-component tooth, and in some embodiments, one or more U-shaped clips may collectively form a multi-component tooth with other parts or components (e.g., non-U-shaped clips; see, e.g., FIGS. 11D, 12A).

[0062] For example, in the exemplary electric machine 10D of FIG. 8 , each multi-component tooth 50 is formed by tooth portions of a plurality of U-shaped clips. The plurality of U-shaped clips in the embodiment of FIG. 8 includes a plurality of sets of a first U-shaped clip 52, a second U-shaped clip 54, and a third U-shaped clip. The first U-shaped clip and the second U-shaped clip are disposed on opposite sides (e.g., top and bottom) of the third U-shaped clip 56. For simplicity, the U-shaped clips will be simply referred to as clips (e.g., the first clip 52, the second clip 54, and the third clip 56). As described in more detail below, the clips include one or more teeth (e.g., one tooth or multiple teeth) that can be positioned inside the coil opening 74 of the coil 70 to collectively fill the coil opening and form the multi-component tooth 50. In some embodiments, only a portion of each coil opening 74 may be filled with the teeth of the U-shaped clip. The remaining portion of each coil opening may be filled with teeth from another component (e.g., a component other than the U-shaped clip). That is, in such an embodiment, one or more teeth from the U-shaped clip and one or more teeth from these other components collectively fill the coil opening, forming multi-component teeth 50. FIG. 10A shows an enlarged view of a set of first clip 52, second clip 54, and third clip 56 positioned near two adjacent coils 70A and 70B. Note that FIG. 10A shows only a portion of coil 70A. While not required, in some embodiments, first clip 52 and second clip 54 may be substantially similar in shape and size, as shown in FIG. 10A. It is also contemplated that in some embodiments, first clip 52, second clip 54, and third clip 56 may be substantially similar in size and shape.

[0063] As explained above, the configurations of the first clip 52, second clip 54, and third clip 56 shown in FIG. 10A are merely exemplary, and clips of the present disclosure may have many different configurations. For brevity, only the configuration of the first clip 52 is discussed below. This discussion is equally applicable to the second clip 54. FIGS. 11A-11E illustrate several exemplary first clips 52 that may be used in the electric machines of the present disclosure. For example, as shown in FIG. 11A, in some embodiments, the first clip 52 may resemble a ring with a plurality of teeth 52D extending radially therefrom. The ring-shaped portion of the clip, when assembled onto the stator 30 (as shown in FIG. 8), may extend around the rotational axis 20, as shown in FIG. 11A. The ring-shaped portion of the clip 52 may be cut at any location to form other embodiments of the clip. For example, Figures 11B-11E show an embodiment in which a ring-shaped portion is cut at different locations to form an arc-shaped yoke 52C with teeth extending radially therefrom. In the embodiment of Figure 11C, the ring-shaped portion (of Figure 11A) is cut into two equal halves, resulting in an arc-shaped yoke 52C in the shape of a semicircle. In the embodiment of Figure 11D, the ring-shaped portion (of Figure 11A) is cut into multiple sections, resulting in one tooth 52D extending centrally from the arc-shaped yoke 52C. In the embodiment of Figure 11E, the ring-shaped portion (of Figure 11A) is cut into sections through the centers of two adjacent teeth 52D, resulting in an arc-shaped yoke 52C having two teeth (e.g., first tooth 52A and second tooth 52B) extending radially from opposite ends of the yoke 52C. As is apparent from FIGS. 11A-11E, the first clip 52 and second clip 54 of the present disclosure may include an arc-shaped yoke having any number of teeth extending radially therefrom (e.g., along radial axis 90). In each embodiment (e.g., as shown in FIGS. 11A-11E), the cross-sectional shape of the teeth in axial plane 22 is semi-trapezoidal, as shown schematically in FIG. 11F. In the embodiment of FIGS. 11A-11D, the cross-sectional shape of the teeth in a radial plane (perpendicular to rotation axis 20) is trapezoidal. Also, in the embodiment of FIG. 11E, the cross-sectional shape of the teeth in the radial plane is semi-trapezoidal.As previously described, in some embodiments, the first clip 52 and the second clip 54 may be substantially similar. For example, both the first clip 52 and the second clip 54 may have the same configuration (e.g., similar to one of FIGS. 11A-11E). However, this is not a requirement, and in some embodiments, the first clip 52 and the second clip 54 may have different configurations. For example, the first clip 52 may have a configuration similar to one of FIGS. 11A-11E, and the second clip 54 may have a configuration similar to another one of FIGS. 11A-11E. In some embodiments, both the first clip 52 and the second clip 54 may be used, as shown in FIGS. 8, 10A, and 10B. In some embodiments, only one of the first clip 52 or the second clip 54 may be used (e.g., one of the first clip 52 or the second clip 54 may be eliminated).

[0064] 12A-12D illustrate some exemplary third clips 56 that may be used in the electric machines of the present disclosure. In some embodiments, as shown in FIGS. 8, 10A, and 10B, the third clip 56 may be positioned (or sandwiched) axially (e.g., along the axis of rotation 20) between the first clip 52 and the second clip 54. In some embodiments, a single third clip 56 may be positioned between the first clip 52 and the second clip 54 (as shown in FIGS. 8, 10A, and 10B). In some embodiments, multiple third clips (e.g., 56, 56′, etc.) may be positioned between the first clip 52 and the second clip 54. As shown in the embodiments of FIGS. 12A-12D, the third clip 56 may generally include an arc-shaped yoke 56C with one or more teeth extending radially therefrom (e.g., along the radial axis 90). For example, as shown in FIG. 12A , the third part 56 may include an arc-shaped yoke 56C with a single tooth 56D centered on the yoke 56C and extending radially therefrom. In some embodiments, as shown in FIG. 12B , the arc-shaped yoke 56C may be a section of a ring-shaped component with multiple teeth 56D extending radially therefrom. While FIG. 12B illustrates a yoke 56C with two teeth 56D, this is exemplary only. Generally, any number of evenly spaced teeth 56D (e.g., three, four, or any other integer number) may extend radially from the yoke 56C to form the third clip 56. In some embodiments, the third clip of FIG. 12C may be cut through the centers of two adjacent teeth 56D to form the third clip 56 shown in FIG. 12C . The third clip 56 of FIG. 12C includes an arc-shaped yoke 56C with two teeth (e.g., a first tooth 56A and a second tooth 56B) extending radially therefrom. In some embodiments, as shown in Figure 12D, any two (or more) similarly configured third clips 56, 56' may be stacked one on top of the other and positioned between the first clip 52 and the second clip 54. While Figure 12D shows two stacked third clips having the configuration shown in Figure 12C, this is for illustrative purposes only.Any third clip 56 (eg, any one of the clips shown in Figures 12A-12C) may be stacked, and any number of such clips may be stacked.

[0065] According to some disclosed embodiments, each U-shaped clip includes a first tooth, a second tooth, and a yoke interconnecting the first tooth and the second tooth. As previously explained, as used herein, "tooth" simply refers to a protrusion or projection. In a radial-flux electric machine, this protrusion or projection may protrude or extend radially toward or away from the axis of rotation of the machine. A first tooth may refer to one tooth, and a second tooth may refer to another tooth (different from the first tooth). The first tooth and the second tooth may have any shape and size. Although not required, in some embodiments, the first tooth and the second tooth of the same clip may have the same shape and / or size. As used herein, a "yoke" refers to a part, portion, or component that connects two or more parts together. Thus, a yoke interconnecting two objects may be any part that connects (joins, couples, or attaches) the two objects together. A yoke may have any shape and size. In some embodiments, the yoke may be curved. In some embodiments, the yoke may have an arcuate shape. In other words, in some embodiments, the shape of the yoke (in the radial plane) may resemble a portion of the boundary of a circle.

[0066] Referring to the exemplary embodiment of the U-shaped clip shown in FIG. 10A, the first clip 52, the second clip 54, and the third clip 56 each include two teeth interconnected by a yoke. For example, the first clip 52 includes a first tooth 52A and a second tooth 52B interconnected by a yoke 52C. Similarly, the second clip 54 includes a first tooth 54A and a second tooth 54B interconnected by a yoke 54C, and the third clip 56 includes a first tooth 56A and a second tooth 56B interconnected by a yoke 56C. The exemplary embodiments of the first clip 52 and the second clip 54 shown in FIGS. 11A-11C and 11E also include multiple teeth interconnected by an arc-shaped yoke 52C. Similarly, the exemplary embodiment of the third clip 56 shown in FIGS. 12B-12D also includes multiple teeth interconnected by an arc-shaped yoke 56C.

[0067] According to some disclosed embodiments, a first tooth of each U-shaped clip is disposed within one coil opening of the plurality of coils, a second tooth of each U-shaped clip is disposed within another coil opening of an adjacent coil, and the yoke bridges the two adjacent coils. As used herein, the term "disposed within" refers to being at least partially positioned within or located within. For example, when an object is disposed within an opening, it may indicate that the object is at least partially positioned within the opening. Additionally, the term "bridging" refers to extending at least partially between. For example, when used herein, when a part bridges two adjacent objects, it may indicate that the part at least partially extends between (or spans) the two adjacent objects. 8, 10A, and 10B, when clips 52, 54, and 56 are combined together to form multi-component tooth 50 (see FIG. 8), the first tooth 52A of a first clip 52 may be disposed within opening 74A of coil 70A when its second tooth 52B is disposed within opening 74B of coil 70B positioned adjacent to coil 70A. Similarly, the first tooth 54A of a second clip 54 may be disposed within coil opening 74A when its second tooth 54B is disposed within coil opening 74B, and the first tooth 56A of a third clip 56 may be disposed within coil opening 74A and its second tooth 56B may be disposed within coil opening 74B. When the first and second teeth of the clips 52, 54, and 56 are positioned in the coil openings 74A, 74B of adjacent coils 70A, 70B in this manner, the arc-shaped yokes 52C, 54C, and 56C of these clips 52, 54, and 56 may bridge the adjacent coils 70A, 70B (see FIG. 8). In the exemplary embodiment of the first clip 52 and the second clip 54 shown in FIGS. 11A-11C and 11E, when any two adjacent teeth 52D of these clips (or teeth 52A and 52B in FIG. 11E) are disposed in the coil openings of two adjacent coils, the arc-shaped yoke 52C between the two teeth 52D may bridge the two adjacent coils.Similarly, in the exemplary embodiment of the third clips 56 shown in Figures 12B-12D, when any two adjacent teeth 56D of these clips are disposed within the openings of adjacent coils, an arc-shaped yoke 56C between the adjacent teeth may bridge the two adjacent coils.

[0068] According to some disclosed embodiments, two sidewalls of two adjacent coils are sandwiched between the first and second teeth of each U-shaped clip. A "sidewall" refers to a surface, boundary, or face located on a side of something (in this case, a side of a coil). For example, for an object having a closed shape (e.g., a cylinder, oval, ellipse, square, rectangle, triangle, or any other shape whose sides intersect to enclose a space), each side of the object can be a sidewall. The term "sandwiched" refers to being at least partially positioned or disposed between at least two objects (in this case, at least partially between two teeth). In some embodiments, when a first object is sandwiched between two objects, the first object can be compressed or pressed between the two objects. 8, 10A, and 10B, when the first tooth 52A of the first clip 52 is positioned within the coil opening 74A (of the coil 70A) and the second tooth 52B of the first clip 52 is positioned within the coil opening 74B (of the adjacent coil 70B), the two sidewalls (designated A and B in FIGS. 8 and 10B) of the adjacent coils 70A and 70B positioned between the first tooth 52A and the second tooth 52B are sandwiched between these two teeth. Similarly, when the first tooth 54A and the second tooth 54B of the second clip 54 are positioned within the coil openings 74A and 74B, respectively, the two sidewalls A and B of the adjacent coils 70A and 70B are sandwiched between the two teeth 74A, 74B. Additionally, when the first tooth 56A and the second tooth 56B of the third clip 56 are positioned within the coil openings 74A and 74B, respectively, the sidewalls of the adjacent coils 70A and 70B are sandwiched between the teeth 76A and 76B. Meanwhile, as seen in FIG. 10B , the multiple teeth (e.g., 52A, 52B, 54A, 54B, 56A, 56B) disposed within each coil opening 74 collectively form a multi-piece tooth 50 that fills the opening 74. In some embodiments, the teeth may be sized such that the total size of the tooth (e.g., the size of the multi-piece tooth 50 formed by the multiple teeth) is slightly larger than the size of the opening 74. In such embodiments, the wire of the coil 70 may stretch to expand the opening 74 to accommodate multiple members therein.

[0069] As previously explained, the teeth used to form the multi-component tooth 50 in some embodiments of the electric machine may have different configurations. Figures 13A and 13B illustrate an embodiment in which the multi-component tooth 50 is formed using a first clip 52 and a second clip 54 having the configuration shown in Figure 11B together with a third clip 56 having the configuration shown in Figure 12C. In this embodiment, similar to the embodiment of Figures 10A and 10B, when one tooth of each clip 52, 54, 56 is disposed within the coil opening 74 of one coil 70 and another tooth of the same clip 52, 54, 56 is disposed within the coil opening 74 of an adjacent coil 70, the yoke of each clip bridges the two adjacent coils, and the two sidewalls of these adjacent coils are sandwiched between the two teeth of each clip. Meanwhile, the teeth in the coil opening 74 fill the coil opening 74 and collectively form the multi-component tooth 50. For example, two adjacent teeth 52D of the semicircular first clip 52 are positioned within the coil openings 74 of two adjacent coils, such that the arc-shaped yoke 52C between (and interconnecting) the two adjacent teeth 52D bridges the two adjacent coils 70, and the two teeth 52D sandwich the sidewalls of the two adjacent coils positioned therebetween. The teeth 54D of the similarly shaped second clip 54 are disposed within the adjacent coil openings 74 in a similar manner, sandwiching the sidewalls of the two adjacent coils. As described with reference to FIGS. 10A and 10B , the two teeth 56A and 56B of each third clip 56 are also disposed within the coil openings 74 of the adjacent coils 70, such that the two teeth 56A, 56B sandwich the sidewalls of the two adjacent coils, while the yoke 56C bridges the two adjacent coils.

[0070] 14A and 14B illustrate an embodiment in which a multi-component tooth 50 is formed using a first clip 52 and a second clip 54 having the configuration shown in FIG. 11B together with a third clip 56 having the configuration shown in FIG. 12A. In this embodiment, as described with reference to FIGS. 13A and 13B, when one tooth 52D of a first clip 52 is disposed within the coil opening 74 of one coil 70 and another tooth 52D of the same first clip 52 is disposed within the coil opening 74 of an adjacent coil 70, a yoke 52C interconnecting the two teeth 52D bridges the two adjacent coils 70. Also, in this configuration, the two sidewalls of the adjacent coils 70 are sandwiched between the two teeth 52D of the first clip 52. Similarly, when one tooth 54D of a second clip 54 is disposed within the coil opening 74 of one coil 70 and another tooth 54D of the same second clip 54 is disposed within the coil opening 74 of an adjacent coil 70, the yoke 54C of the second clip 54 bridges the two adjacent coils 70, and the two side walls of these adjacent coils 70 are sandwiched between the two teeth 54D.

[0071] 15A-15C show an embodiment in which a multi-component tooth 50 is formed using a first clip 52 and a second clip 54 having the configuration shown in FIG. 11B together with a third clip 56 having the configuration shown in FIG. 12B. In this embodiment, as described with reference to FIGS. 13A and 13B, when one tooth 52D, 54D of each clip 52, 54 is disposed within the coil opening 74 of one coil 70 and another tooth of the same clip 52, 54 is disposed within the coil opening 74 of an adjacent coil 70, the yokes 52C, 54C of the clips 52, 54 bridge the two adjacent coils 70, and the two side walls of these adjacent coils 70 are sandwiched between the two teeth 52D, 54D of the clips 52, 54. Furthermore, in this embodiment, when one tooth 56D of the third clip 56 is disposed in the coil opening 74 of one coil 70 and its other tooth 56D is disposed in the coil opening 74 of the adjacent coil 70, the yoke 56C of the clip 56 bridges the two adjacent coils 70, and the two sidewalls of these coils 70 are sandwiched between the two teeth 56D. In some embodiments, the electric machine includes a stator positioned radially outward of the rotor, with the plurality of U-shaped clips forming part of the stator. As previously described, in some embodiments, the disclosed electric machine may be an inner-rotor electric machine in which the rotor is positioned radially inward of the stator. For example, FIG. 8 illustrates an exemplary inner-rotor electric machine in which the rotor 40 (not shown in FIG. 8) is positioned radially inward of the stator 30. As shown in FIGS. 8 and 10A-10B, the teeth of first clip 52, second clip 54, and third clip 56 form each multi-component tooth 50 of stator 30. As shown in FIG.

[0072] In some disclosed embodiments, each coil opening includes multiple teeth disposed along the length of the opening. A tooth is disposed along the length of the opening if at least a portion of the teeth extend at least partially along the height of the opening. As a non-limiting example, a single tooth may extend the entire height of the coil opening. In some embodiments, multiple coils 70 may be symmetrically disposed along the axis of rotation 20, such that the length dimension of the coil opening 74 extends along the axis of rotation 20 (see, e.g., FIGS. 8, 13B, 14A, 14B, and 15A-15C). In some embodiments, multiple teeth may be disposed along the length of each coil opening (see, e.g., FIGS. 8, 10B, 13B, 14A, and 15C). For example, in the electric machine embodiment shown in FIGS. 8 and 10B, teeth 52A, 56A, and 54A (or teeth 52B, 56B, and 54B) are disposed along the length of each coil opening 74. Also, in the embodiment of Figure 13B, teeth 52D, 56A (or 56B), and 54D extend along the length of each coil opening 74. Similarly, in the embodiments of Figures 14A and 15C, teeth 52D, 56D, and 54D are disposed along the length of the opening. In some embodiments, these teeth may fill the entire length of each coil opening 74, such that the teeth within opening 74 and the opposing sidewalls of the coil engage with one another along at least a portion of the length of opening 74.

[0073] In some disclosed embodiments, one or more teeth of the plurality of teeth fill the entire width of each opening. Filling the entire width of an opening refers to a situation in which the tooth extends between opposing sidewalls of the coil opening, such that the width dimension of the tooth substantially corresponds to the width dimension of the coil. As previously described, the coil 70 may be centered about the axis of rotation 20, such that the length dimension of each coil opening 74 extends along the axis of rotation 20. When positioned in this manner, the width dimension of each coil opening 74 may extend perpendicular to its length dimension. In some embodiments of the electric machine, one or more teeth of the plurality of teeth positioned along the length of each opening 74 may fill the entire width of the opening 74 along at least a portion of the length of the tooth or teeth. As used herein, when a tooth (e.g., tooth A) fills the entire width of an opening 74, tooth A inside the opening 74 and the opposing sidewalls of the coil 70 may engage each other along at least a portion of the length of tooth A. Note that in some embodiments, the wire 72 forming the coil 70 (see, e.g., FIGS. 9A-9C ) may be coated with a thin layer of non-conductive insulating material (e.g., plastic, enamel, or another non-conductive material) to prevent current from passing between the turns of the wire. Thus, when the opposing sidewalls of the coil and the teeth engage with each other, they may not be in direct physical contact with each other. Instead, they may be in indirect contact through the insulating material. In the embodiment of FIGS. 8 and 10B , the teeth 52A and 52B may collectively fill the entire width of each opening 74 at one end of the opening, the teeth 54A and 54B may fill the entire width of each opening 74 at the opposite end of the opening, and the teeth 56A and 56B may fill the entire width of each opening between the two opposing ends. Similarly, in the embodiment of Figure 13B, a single tooth 52D may fill the entire width of the coil opening at one end, tooth 54D may fill the entire width of the opening at the opposite end, and teeth 56A and 56B may together fill the entire width of the opening in the region between its opposite ends. Also, in the embodiment of Figures 14A and 15C, tooth 52D may fill the entire width of each opening 74 at one end, tooth 54D may fill the entire width of the opening at its opposite end, and tooth 56D may fill the entire width of the opening in the region between the two ends.

[0074] In some disclosed embodiments, a single tooth of the plurality of teeth fills the entire width of each opening. Multiple teeth filling the entire width of an opening refers to a situation in which more than one tooth “works together” to fill the width of a coil opening. For example, the overall width of two teeth in a coil opening may substantially match the width of the coil opening. As explained above, in some embodiments of the disclosed electric machines, a single tooth fills the entire width of a coil opening. For example, in the embodiment of FIG. 13B , a single tooth 52D may fill the entire width of a coil opening at one end of the opening, and a single tooth 54D may fill the entire width of the opening at the opposite end of the opening. Similarly, in the embodiments of FIGS. 14A and 15C , a single tooth 52D may fill the entire width of opening 74 at one end of the opening, a single tooth 54D may fill the entire width of the opening at the opposite end, and a tooth 56D may fill the entire width of the opening in the region between the two opposing ends.

[0075] In some disclosed embodiments, the plurality of teeth includes at least upper teeth, lower teeth, and center teeth, with at least one of the upper teeth or lower teeth filling the entire width of each opening and including an arc-shaped yoke from which the plurality of teeth extend. The terms "upper," "lower," and "center" indicate relative positions with respect to the orientation (of the electric machine) being displayed or viewed. In any orientation, an "upper" tooth may be any tooth positioned above the "center" tooth; a "lower" tooth may be any tooth positioned below the center tooth. For example, in FIG. 8, teeth 52A and 52B may be upper teeth, teeth 56A and 56B may be center teeth, and teeth 54A and 54B may be lower teeth. If the orientation is reversed (or 180° o For example, in the inverted orientation of FIG. 8 (e.g., the paper is 180° oWhen rotated, teeth 54A and 54B may be upper teeth, and teeth 52A and 52B may be lower teeth. The term "arc" refers to a curve having a constant or variable radius. Thus, an "arc-shaped" yoke may refer to a yoke having a similarly curved shape. In some embodiments, the arc or curve may follow a chord of a circle. Thus, in some embodiments, an arc-shaped yoke may be shaped like a chord of a circle (e.g., curved with a constant radius). In each of the exemplary embodiments of the electric machine shown in FIGS. 13B, 14A, and 15C, the plurality of teeth in each coil opening 74 includes at least upper teeth (52D), lower teeth (54D), and a center tooth (56A and 56B in FIG. 13B and 56D in FIGS. 14A and 15C). Also, in each of these embodiments, both the upper and lower teeth 52D, 54D fill the entire width of the opening 74 and include an arc-shaped yoke 52C, 54C (see, e.g., FIG. 11B ) from which the plurality of teeth 52D extend. In some embodiments, these teeth 54D may extend radially along the radial axis 90 of the electric machine.

[0076] According to some disclosed embodiments, each coil opening includes at least one first tooth from a first group of the plurality of U-shaped clips and at least one first tooth from a second group of the plurality of U-shaped clips, the first group being different from the second group. Teeth from each of two different groups may be positioned in each opening. For example, in the exemplary embodiment of the electric machine shown in FIGS. 8 and 10B , each coil opening 74 includes a first tooth 52A from a first clip 52, a first tooth 54A from a second clip 54, and a first tooth 56A from a third clip 56. Of these clips, the third clip 56 may form a first group of clips, and the first clip 52 and the second clip 54 may form a second group of clips. As previously described, the first clip 52 and the second clip 54 may be similar in shape and size and may be interchangeable. For example, as is apparent from FIGS. 10A , 11E, and 12C , the first clip 52 and the second clip 54 are different from the third clip 56. In some embodiments, at least one first tooth in the first group has a length greater than the length of at least one first tooth in the second group. For example, in the exemplary embodiment of FIGS. 8 and 10B, the first tooth 56A of the third clip 56 has a length greater than the first tooth 52A of the first clip 52 and the first tooth 54A of the second clip 54 (see, e.g., FIGS. 10A, 10B, 11E, and 12C). In some embodiments, at least two first teeth in the second group have a common length. As explained above, in the embodiment of FIGS. 8 and 10B, the first clip 52 and the second clip 54 may form a second group of clips. As also explained above, the tooth 52A of the first clip 52 and the tooth 54A of the second clip 54 may be similar in shape and size and may be interchangeable. Thus, the teeth 52A and 54A may have a common length (see, e.g., FIG. 10A). In some embodiments, a plurality of first teeth and a plurality of second teeth are disposed within each coil opening, and at least one pair of specific first teeth and specific second teeth has a length greater than the lengths of the other first teeth and second teeth disposed within each coil opening.8 and 10A-10B, a plurality of first tines (e.g., first tines 52A, 54A, 56A) and a plurality of second tines (e.g., 52B, 54B, and 56B) are disposed within each coil opening 74. Also, as described above, the first tines 56A and second tines 56B in an opening 74 have a length that is greater than the lengths of the other first tines and second tines in that opening.

[0077] According to some disclosed embodiments, a group of U-shaped clips has a first tooth disposed within the coil opening of one of the coils, and at least one U-shaped clip in the group has a wedge-shaped first tooth. "Wedge-shaped" refers to a shape having a wider end and a narrower end. For example, one end of the wedge-shaped part may be wider than the opposite end, and the part may taper from the wider end to the narrower end. For example, in the exemplary embodiment shown in FIGS. 10A and 10B , the first tooth of a group of U-shaped clips, including a first clip 52, a second clip 54, and a third clip 56, is disposed within the coil opening 74 of the coil 70. For example, the first tooth 52A of the first clip 52, the first tooth 54A of the second clip 54, and the first tooth 56A of the third clip 56 are disposed within the coil opening 74. Also, as best seen in FIG. 10A , each of the first teeth 52A, 54A, and 56A is wedge-shaped. For example, each tooth has a width “x” (e.g., a dimension extending perpendicular to the radial axis 90 in the radial plane) that tapers from a wider end to a narrower end along the radial axis 90. In some embodiments, at least one U-shaped clip in the group has a wedge-shaped second tooth. As also seen in FIG. 10A , the second tooth 52B of the first clip 52, the second tooth 54B of the second clip 54, and the second tooth 56B of the third clip 56 are also wedge-shaped. In some embodiments, the first and second teeth of the same clip may have similar shapes (e.g., the first tooth 52A may have a similar shape to the second tooth 52B, the first tooth 56A may have a similar shape to the second tooth 56B, etc.). In some embodiments, the first and second teeth of the same clip may be mirror images of each other about an axial plane that passes through the center of the yoke interconnecting the first and second teeth. In some embodiments, the length dimension of each wedge-shaped first tooth varies from one end of the coil opening to the opposite end of the coil opening. The length dimension of the clip may refer to the dimension of the clip in an axial plane that extends parallel to the axis of rotation. As previously described with reference to FIG. 10A , the first teeth 52A, 54A, and 56A of the first, second, and third clips 56 are wedge-shaped.As can also be seen in FIG. 10A, in addition to the width "x" of the first tooth 52A (e.g., wedge-shaped) varying, the length "y" of the first tooth 52A of the first clip 52 (and the first tooth 54A of the second clip 54) also varies along the radial axis 90 from the second end 78 of the coil opening 74 to its first end 76.

[0078] According to some embodiments, at least one U-shaped clip in the group is made from an SMC material. Soft Magnetic Composite (SMC) is a class of magnetic material composed of finely divided magnetic particles embedded in a non-magnetic or insulating binder material. Any suitable SMC may be used. Typically, SMC parts are made from bonded iron powder coated with an insulating layer and pressed into a solid material using a die before a final heat treatment to harden the bond. For example, a part made from ferromagnetic powder may be coated with a uniform layer of electrically insulating film and pressed to form the part. In various embodiments of the present disclosure, the SMC may include one or more isotropic ferromagnetic materials having a magnetic saturation induction of at least 1.6 Tesla and an electrical resistivity greater than 10 microohms / meter. Referring to FIG. 10A , in some embodiments, one or more of the first clip 52, second clip 54, and third clip 56 (disposed within each coil opening 74) may be made from an SMC. In some embodiments, all of the U-shaped clips in the group are made from an SMC material. For example, each of the first clip 52, second clip 54, and third clip 56 (disposed within each coil opening 74) can be made from an SMC. In some embodiments, all of the U-shaped clips in the group are made from laminated steel. Laminated steel, also known as "composite steel" or "layered steel," is a type of material comprised of multiple steel layers bonded or otherwise connected to one another. For example, one or more (e.g., all) of clips 52, 54, and 56 (e.g., of FIG. 10A ) can be made from steel laminate or other suitable material.

[0079] As previously described, an electric machine of the present disclosure may include multiple U-shaped clips, each clip having first and second teeth interconnected by a yoke. In some embodiments, multiple yokes cooperate to form a ring. As used herein, a "ring" refers to a substantially circular shape. For example, one or more components or objects arranged in a substantially circular shape. As used herein, the term "cooperate" means to act in cooperation. For example, the yokes jointly or collectively form a substantially circular shape. In embodiments of the present disclosure, the yokes 52C, 54C, and 56C of the first clip 52, the second clip 54, and the third clip 56, respectively, cooperate to form a ring. In some embodiments, multiple yokes cooperate to form a first ring and a second ring. For example, in the embodiment of FIGS. 8 and 10B, when the first teeth 52A and second teeth 52B of the first clip 52 are positioned within the coil openings 74 of each coil 70, the yokes 52C of adjacent first clips 52 cooperate to form a ring (see, e.g., FIGS. 8 and 10B). Similarly, when the first tooth 54A and second tooth 54B of a second clip 54 are positioned within each coil opening 74, the yokes 54C of adjacent second clips 54 also cooperate to form another ring (see, for example, FIG. 8). Additionally, when the first tooth 56A and second tooth 56B of a third clip 56 are positioned within each coil opening 74, the yokes 56C also cooperate to form yet another ring. In some embodiments, the yokes of groups from multiple U-shaped clips are interconnected. In the embodiment shown in FIGS. 13A-15C, after assembly, the yokes 52C of the first clip 52 cooperate to form one ring, and the yokes 54C of the second clip 54 cooperate to form another ring (see FIGS. 13A-15C). In these embodiments, the first clip 52 and the second clip 54 have the configuration shown in FIG. 11B. In the first clip 52 and the second clip 54 shown in FIG. 11B, multiple U-shaped clips are interconnected by a common yoke.

[0080] In some embodiments, multiple standalone U-shaped clips are disposed between the first and second rings. As used herein, a "standalone" U-shaped clip refers to a clip that can be used alone or separately. For example, a U-shaped clip that is not connected to anything else (e.g., other U-shaped clips) may be referred to as a standalone U-shaped clip. As previously explained, the term "U-shaped" clip indicates that at least some portion of the clip (e.g., the entire clip or one or more portions of the clip) resembles a capital letter U. A standalone U-shaped clip may be a clip in which the entire piece has a generally U-shape. Several embodiments of a standalone U-shaped clip are shown in Figures 11E and 12B-12D. Note that these illustrations of standalone U-shaped clips are merely exemplary, and many other configurations are contemplated. In some embodiments of the present disclosure, multiple standalone U-shaped third clips 56 are disposed between two rings collectively formed by the yoke 52C of the first clip 52 and the yoke 54C of the second clip 54 (see, e.g., Figures 8, 10A-10B, and 13A-13B).

[0081] In some embodiments, the opening 74 of each coil 70 may include (or be filled with) a plurality of toothed spacers that collectively form multi-component teeth 50 (see, e.g., FIG. 2C ). According to some disclosed embodiments, an electric machine includes a plurality of coils, where each coil defines a coil opening. As previously described and illustrated, an electromagnetic coil (referred to herein as a “coil”) may include one or more turns of electrical conductor (e.g., wire, multiple twisted strands, strip, foil, or another configuration of electrical conductor) that define a “coil opening” and may extend from one end of the coil to the opposite end of the coil. For example, FIGS. 9A through 9C show several different views of an exemplary coil 70 formed by winding a copper wire 72 that extends from a first end 76 to a second end 78 around a coil opening 74 (or cavity). Generally, the coil 70 may be associated with the rotor 40 or stator 30 of an electric machine. However, the coils 70 may be described herein as being associated with the stator 30. As best seen in FIG. 2B , the electric machine may include multiple coils 70. The coils may be arranged symmetrically about the axis of rotation 20, such that an opening 74 for each coil extends along the radial axis 90 of the machine. A multi-component tooth 50 may be disposed within each coil opening 74. As previously described, the coil openings 74 may generally have the same shape (e.g., a trapezoidal three-dimensional shape) and size as the teeth 50.

[0082] In some embodiments, each coil opening includes a first section, a second section, and a middle section between the first and second sections. As used herein, "section" refers to a portion or region of the coil opening. There need not be any perceptible boundary between the sections. For example, a middle section may refer to an area of ​​the opening that is between other areas that bound it. As an example, a circular hole may be divided into four sections, each representing a different quadrant of the hole. In this example, the circular hole may be divided into two sections, with the portion below an imaginary diameter line representing one section (e.g., the lower section) and the portion above the imaginary diameter line representing the other section (e.g., the upper section). Note that because the line separating these different regions is imaginary, there may be no physical demarcation or boundary between these different regions. Thus, as used herein, the first section, second section, and middle section refer to three different regions into which each coil opening may be arbitrarily divided, with the first and second sections positioned on opposite sides of the middle section. For example, as shown in FIG. 9B , the coil aperture 74 may include a first region 174A, a second region 174B, and an intermediate region 174C positioned between the first and second regions. When the coil 70 is symmetrically disposed about the axis of rotation 20 (see FIG. 10A ), the first region 174A may represent the portion of the aperture 74 near its top end, the second region 174B may represent the portion of the aperture 74 near its bottom end, and the intermediate region 174C may represent the portion of the aperture 74 between its top and bottom ends. As explained above, the first region 174A, the second region 174B, and the intermediate region 174C of the aperture 74 are separated by imaginary lines, so that no physical boundaries exist between these different regions.

[0083] According to some embodiments, an electric machine includes at least one first yoke, at least one second yoke, and at least one intermediate yoke between the at least one first yoke and the at least one second yoke. As previously described, a "yoke" refers to a part, portion, or component that connects two or more parts together, regardless of shape. In other words, the term "yoke" does not imply any requirement regarding the shape, structure, or configuration of a part. Unless a particular shape is explicitly specified, a yoke may have any shape and configuration (straight, curved, or other). The first yoke, second yoke, and intermediate yoke refer to three distinct yokes, with the intermediate yoke positioned between the first yoke and second yoke. Each of these three yokes may have any shape (e.g., the same or different shapes). For example, as previously described with reference to FIG. 10A , the first clip 52, second clip 54, and third clip 56 each include a yoke. For example, first clip 52 includes yoke 52C, second clip 54 includes yoke 54C, and third clip 56 includes yoke 56C. In embodiments of the electric machine in which third yoke 56C is positioned between yokes 52C and 54C (see, e.g., FIGS. 10A-10B), yoke 56C may be referred to as an intermediate yoke. When these spacers or clips (52, 54, 56) are assembled within the electric machine (see, e.g., FIG. 10B), their respective yokes 52C, 54C, and 56C cooperate (or collectively) to form a ring around rotational axis 20. The exemplary embodiment of spacer or clip 52, 54 shown in FIGS. 11A-11C and 11E also includes yoke 52C, and the exemplary embodiment of spacer or clip 56 shown in FIGS. 12B-12D includes yoke 56C. In each of these embodiments, the yokes (e.g., yokes 52C, 54C, and 56C) are curved and arc-shaped. As previously explained, in an arc-shaped yoke, the yoke may be shaped like a chord of a circle (eg, it may be curved at a constant radius).In embodiments of the electric machine in which yoke 56C is positioned between yokes 52C and 54C (see, e.g., FIGS. 13A-15C), yoke 56C may be referred to as the intermediate yoke, with one of yokes 52C or 54C being the first yoke and the other being the second yoke. When these spacers or clips 52, 54, 56 are assembled in the electric machine (see, e.g., FIGS. 13A-15C), the yokes of each clip cooperate to form a ring that extends around the rotational axis 20.

[0084] Some disclosed embodiments include a plurality of first wedge-shaped teeth integrally formed with and extending from at least one first yoke; a plurality of second wedge-shaped teeth integrally formed with and extending from at least one second yoke; and a plurality of intermediate wedge-shaped teeth integrally formed with and extending from at least one intermediate yoke. The terms "teeth" (and its singular form "tooth") and "wedge-shaped" may be interpreted as previously explained and exemplified. For example, the teeth (and the singular tooth) may include any protrusion or projection, and wedge-shaped refers to a shape having a wider end and a narrower end. Thus, a wedge-shaped tooth (or wedge-shaped teeth) may refer to a protrusion with one end wider than its opposite end. For example, the wedge-shaped tooth may taper from the wider end to the narrower end. In some exemplary embodiments (e.g., radial-flux electric machines), teeth may be protrusions that project along the radial axis of the machine (e.g., toward or away from the axis of rotation). For example, in the exemplary outer-rotor electric machine 10 of FIG. 2A , teeth 50 project radially away from the axis of rotation 20 from the stator 30 toward the rotor 40, while in the exemplary inner-rotor electric machine 10A of FIG. 2C , teeth 50 project radially toward the axis of rotation 20 from the stator 30 toward the rotor 40. Thus, in such embodiments, wedge-shaped teeth may be protrusions that are wider at one end along the radial axis and narrower at the other end along the radial axis. The term “integrally formed” refers to being connected together to form a single, complete member or unit. Integrally formed may occur when multiple parts are made from the same piece of material, made from different pieces of material joined together, or otherwise coupled together to establish a connection that is intended to be permanent. For example, an integrally formed part may not be easily disassembled into sub-parts without compromising the integrity of the part. An integrally formed part may act as a single, complete member or unit overall.

[0085] With reference to the exemplary embodiment shown in FIG. 10A, the yoke 52C (of the first clip 52) includes a plurality (or pair) of teeth (e.g., first tooth 52A and second tooth 52B), the yoke 54C (of the second clip 54) includes a plurality of teeth (e.g., first tooth 54A and second tooth 54B), and the yoke 56C (of the third clip 56) includes a plurality of teeth (e.g., first tooth 56A and second tooth 56B). Similarly, in the exemplary embodiment shown in FIGS. 11A-11C and 11E, the yoke 52C includes a plurality of teeth, and in the exemplary embodiment shown in FIGS. 12B-12D, the yoke 56C includes a plurality of teeth. In each of these embodiments, the plurality of teeth are integrally formed with the yoke and extend from the yoke along the radial axis 90 toward the rotational axis 20. Furthermore, each tooth (52A, 52B, 52D, 54A, 54B, 54D, 56A, 56B, 56D) in these embodiments is wedge-shaped. For example, one end of the tooth along the radial axis 90 is wider than the opposite end (see, for example, FIGS. 10A-10B, 11A-11E, and 12A-12D). In some embodiments, at least one first yoke, at least one second yoke, and at least one intermediate yoke are arc-shaped. As previously described, an arc-shaped shape has a curved shape, such as the shape of a chord of a circle (e.g., a curve with a constant radius). As shown in FIGS. 11A-11E, in some embodiments, the first yoke 52C and the second yoke 54C of the first clip 52 and the second clip 54 are arc-shaped. Similarly, in some embodiments, the intermediate yoke 56C of the third clip 56 is also arc-shaped, as shown in FIGS. 12A-12D. In some embodiments, at least one intermediate yoke includes two stacked intermediate yokes. Stacked refers to one adjacent to (e.g., on top of) another. In some embodiments, a third clip having the configuration shown in FIG. 12D, for example, may be used to form multi-component teeth 50. In such an embodiment of the electric machine, the intermediate yoke may include two intermediate yokes 56C, 56C' stacked one on top of the other. According to some embodiments, the plurality of first wedge-shaped teeth and the plurality of second wedge-shaped teeth share a common size and shape. Teeth sharing a common size and shape have substantially the same contour.In some embodiments, the first clip 52 may have the same size and shape as, and be interchangeable with, the second clip 54 (see, e.g., FIGS. 11A-11E). In such embodiments, the teeth of these clips 52, 54 may also have the same size and shape.

[0086] In some disclosed embodiments, each of the plurality of first wedge-shaped teeth extends within a first section of a different one of the plurality of coil openings. "Extending within different openings" refers to a situation in which each of the first wedge-shaped teeth is positioned within its own opening, and in this example, is positioned in the same section (first section) of the different openings. For example, referring to FIGS. 10A and 10B , when the spacer or first clip 52 is assembled with multiple coils 70, the first tooth 52A of each first clip 52 extends within the first section 174A of the coil opening 74 of the coil 70A, and the second tooth 52B of that first clip 52 extends within the first section 174A of the coil opening 74 of the adjacent coil 70B. 13A and 13B, when the half-ring-shaped first clip 52 (of FIG. 11C) is assembled into the coil 70, each tooth 52D of the first clip extends into a different first section 174A of the plurality of coil openings 74. Similarly, with reference to FIGS. 15A-15C, when the first clip 52 (of FIG. 11B) is assembled into the coil 70, each tooth 52D of the first clip extends into a different first section 174A of the plurality of openings 74 of the coil 70. In some embodiments, each of the plurality of second wedge-shaped teeth extends within its second section into a different one of the plurality of coil openings. As with the explanation provided above, "extending into different openings" in this context refers to a situation in which each of the second wedge-shaped teeth is positioned within its own opening, and in this example, is positioned in the same section (the second section) of the different openings. For example, referring to Figures 10A and 10B, when a spacer or second clip 54 is assembled with multiple coils 70, the first tooth 54A of each second clip 54 extends into the second section 174B of the coil opening 74 of the coil 70A, and the second tooth 54B of that second clip 54 extends into the second section 174B of the coil opening 74 of the adjacent coil 70B.13A and 13B, when the semi-ring-shaped second clip 54 (of FIG. 11C) is assembled within the coil 70, each tooth 52D of the second clip extends within the second section 174B of a different one of the plurality of coil openings 74. Similarly, with reference to FIGS. 15A-15C, when the second clip 52 (of FIG. 11B) is assembled within the coil 70, each tooth 52D of the second clip extends within the second section 174B of a different one of the plurality of openings 74 of the coil 70. In some embodiments, the plurality of intermediate wedge-shaped teeth extend within their intermediate sections into different ones of the plurality of coil openings. As with the previous description, "extending within different openings" in this context refers to a situation in which each intermediate wedge-shaped tooth is positioned within its own opening, and in this example, is positioned in the same section (the intermediate section) of the different openings. For example, referring to FIGS. 10A and 10B, when a spacer or intermediate third clip 56 is assembled with multiple coils 70, the first tooth 56A of each third clip 56 extends into the middle section 174C of the coil opening 74 of coil 70A, and the second tooth 56B of that third clip 56 extends into the middle section 174C of the coil opening 74 of the adjacent coil 70B. Similarly, referring to FIGS. 13A and 13B, when an intermediate third clip 56 is assembled within a coil 70, the first tooth 56A and the second tooth 56B of that third clip extend into the middle section 174C of a different one of the multiple coil openings 74. Similarly, referring to FIGS. 15A-15C, when an intermediate third clip 56 (of FIG. 12B) is assembled within a coil 70, each tooth 56D of that intermediate clip extends into the middle section 174C of a different one of the multiple openings 74 of the coil 70.

[0087] According to some disclosed embodiments, a pair of intermediate wedge-shaped teeth is disposed within each coil opening. A pair of intermediate wedge-shaped teeth disposed within the same opening refers to a situation in which two intermediate teeth occupy a middle section of a common coil opening. For example, as shown in the embodiments of FIGS. 8, 10B, and 13B, in some embodiments, a pair of intermediate wedge-shaped teeth 56A, 56B is disposed within the opening 74 of each coil 70. In these exemplary embodiments, a first tooth 56A of a first third clip 56 extends into the middle section 174C of the opening 74 of a coil 70A (see FIGS. 10A-10B), and a second tooth 56B of the same third clip 56 extends into the middle section 174C of the opening 74 of an adjacent coil 70B. Meanwhile, the second tooth 56B of an adjacent third clip 56 (e.g., the third clip to the right of the first third clip) extends into the middle section 174C of the coil 70A to form a pair of intermediate wedge-shaped teeth with the first tooth 56A of the first third clip 56. Also, the first tooth 56A of another adjacent third clip 56 (e.g., the third clip to the left of the first third clip) extends into the middle section 174C of the coil 70B to form a pair of intermediate wedge-shaped teeth with the second tooth 56B of the first third clip 56. In some embodiments, the pair of intermediate wedge-shaped teeth 56A, 56B in each coil opening 74 fills the entire width of the coil opening 74. In some embodiments, the combined width of the pair of intermediate wedge-shaped teeth 56A, 56B may be slightly larger than the corresponding width of the coil opening 74, so that the wire of the coil stretches (or deforms), slightly expanding the coil opening to tightly receive the pair of teeth 56A, 56B. This phenomenon is sometimes referred to as a friction fit.

[0088] In some embodiments, only one first wedge-shaped tooth and only one second wedge-shaped tooth are disposed within each coil opening. In this example, only two teeth are positioned in each coil opening. For example, as shown in the embodiment of FIGS. 13A and 13B , a single wedge-shaped tooth 52D of the first clip 52 and a single wedge-shaped tooth 54D of the second clip 54 are disposed within each coil opening 74, along with a pair of intermediate wedge-shaped teeth 56A, 56B in the intermediate section 174C of each coil opening. Specifically, the first tooth 52D of the first clip 52 is disposed within the first section 174A of the coil opening 74 on one side of the pair of intermediate wedge-shaped teeth 56A, 56B, and the second tooth 54D of the second clip 54 is disposed within the second section 174B opposite the pair of intermediate teeth 56A, 56B. In some embodiments, a pair of first wedge-shaped teeth and a pair of second wedge-shaped teeth are disposed within each coil opening. For example, as shown in the embodiment of FIGS. 8, 10A, and 10B, a pair of first wedge-shaped teeth 52A, 52B are disposed within the first section 174A of the coil opening 74, and a pair of second wedge-shaped teeth 54A, 54B are disposed within the second section 174A of each coil opening 74, along with a pair of intermediate wedge-shaped teeth 56A, 56B in the intermediate section 174C of each coil opening 74. In each of these embodiments, the multiple wedge-shaped teeth in each coil opening 74 may collectively form multi-component teeth 50 having a non-uniform trapezoidal configuration as previously discussed (e.g., with reference to FIGS. 4-7B). In some embodiments, a single intermediate wedge-shaped tooth is disposed within each coil opening. In this example, only one intermediate wedge-shaped tooth is positioned in each coil opening. 15A-15C, in some embodiments, a single intermediate wedge-shaped tooth 56D is disposed within the intermediate section 174C of each coil opening 74. In such embodiments, the first section 174A and the second section 174B of the coil opening 74 may each include a single wedge-shaped tooth (see, e.g., FIGS. 15A-15C) or a pair of wedge-shaped teeth.For example, in an embodiment of an electric machine in which the first clip 52 and the second clip 54 have a configuration such as that shown in FIG. 11E and the intermediate third clip 56 has a configuration such as that shown in FIG. 12B, a multi-component tooth 50 is formed within each coil opening 74 by a single intermediate wedge-shaped tooth 56D, a pair of wedge-shaped teeth 52A, 52B on one side of the intermediate tooth 56D, and another pair of wedge-shaped teeth 54A, 54B on the opposite side of the intermediate tooth 56D.

[0089] According to some embodiments, the multiple coils are symmetrically arranged about the rotational axis of the electric machine, with the coil opening of each coil including a tooth structure formed from a single first wedge-shaped tooth, a single second wedge-shaped tooth, and a pair of adjacently positioned intermediate wedge-shaped teeth. "Symmetrical" refers to a balanced or harmonious arrangement about an axis (in this case, of the coils). For example, the coils may be composed of similar parts facing each other or around the axis. Each coil of the multiple coils may have, for example, a similar configuration or shape and may be mounted around the rotational axis. For example, two symmetrical objects, or symmetrical portions of an arc on which the objects are positioned, may repeat or mirror each other. For example, as shown in FIG. 13B , in some embodiments, multiple coils 70 may be symmetrically arranged about the rotational axis 20, such that the coil opening 74 of each coil 70 extends along the radial axis 90. "Tooth structure" refers to teeth constructed or composed of multiple components. For example, the coil opening 74 of each coil 70 may include a multi-piece tooth 50 formed from a single first wedge-shaped tooth 52D, a single second wedge-shaped tooth 54D, and a pair of adjacently positioned intermediate wedge-shaped teeth 56A, 56B. In some embodiments, the multiple coils are arranged symmetrically about the axis of rotation of the electric machine, and the coil opening of each coil includes a tooth structure formed from a single first wedge-shaped tooth, a single second wedge-shaped tooth, and a single intermediate wedge-shaped tooth. For example, as shown in FIGS. 15A-15B , in some embodiments, each coil opening 74 of the multiple coils 70 arranged symmetrically about the axis of rotation 20 may include a multi-piece tooth 50 formed from a single first wedge-shaped tooth 52D, a single second wedge-shaped tooth 54D, and a single intermediate wedge-shaped tooth 56D.

[0090] In some embodiments, the intermediate wedge-shaped tooth has a wedge shape that differs from the wedge shapes of at least some of the first and second wedge-shaped teeth. As previously described and illustrated, a wedge shape refers to a shape having a wider end and a narrower end. The difference in wedge shape (e.g., between the wedge shapes of the first and intermediate teeth and between the wedge shapes of the second and intermediate teeth) can be of any type. For example, in some embodiments, they can differ in configuration (e.g., wedge-shaped along one plane, wedge-shaped along multiple planes, or another difference in shape), in some embodiments, the widths of the wider and / or narrower ends of the wedge-shaped tooth can differ, in some embodiments, the taper between the wider and narrower ends can differ, etc. In some embodiments, the first, second, and intermediate wedge-shaped teeth may have the same width at the wider and narrower ends and the same taper between the wider and narrower ends. In some embodiments, the intermediate wedge-shaped tooth is wedge-shaped in a first plane, and the first and second wedge-shaped teeth are wedge-shaped in a second plane transverse to the first plane. In some embodiments, the first and second wedge-shaped teeth are also wedge-shaped in the first plane. According to some embodiments, the first plane is perpendicular to the rotational axis of the electric machine. For example, each of the first and second wedge-shaped teeth may be wedge-shaped in both a radial plane (e.g., a plane perpendicular to the rotational axis 20) and an axial plane (the plane in which the rotational axis 20 lies). For example, the wedge-shaped first teeth 52A, 52B, 52D of the exemplary first clip 52 and second clip 54 shown in FIGS. 11A-11E are wedge-shaped in both the radial and axial planes. Specifically, in the radial plane, the widths of the teeth 52A, 52B, 52D decrease along the radial axis 90 toward the rotation axis 20, while in the axial plane, the widths of the teeth 52A, 52B, 52D increase along the radial axis 90 toward the rotation axis 20. Thus, each of the exemplary first wedge-shaped teeth of the first clip 52 and second clip 54 is wedge-shaped or tapered in two mutually perpendicular planes (the axial plane and the radial plane). However, in some embodiments, each intermediate wedge-shaped tooth may be wedge-shaped only in the radial plane, not the axial plane.12A-12D, the wedge-shaped intermediate teeth 56A, 56B, 56D of the exemplary third clip 56 are wedge-shaped in the radial plane but not in the axial plane. In other words, in the radial plane, the widths of the intermediate teeth 56A, 56B, 56D decrease along the radial axis 90 toward the rotation axis 20, while in the axial plane, the widths of the intermediate teeth 56A, 56B, 56D are constant along the radial axis 90.

[0091] According to some embodiments, the at least one first yoke includes a plurality of first yokes, each of which includes a pair of first wedge-shaped teeth extending therefrom. For example, in the embodiment shown in FIGS. 8, 10A, and 10B, a pair of first wedge-shaped teeth 52A, 52B extends from a yoke 52C of each first clip 52 (see, e.g., FIG. 11E). When the wedge-shaped teeth 52A, 52B of a first clip 52 are positioned within the openings 74 of adjacent coils 70, the yokes 52C of the first clips 52 are arranged symmetrically about the rotation axis 20 to form a first ring (see, e.g., FIG. 8) around the plurality of coils 70. In some embodiments, the at least one second yoke includes a plurality of second yokes, each of which includes a pair of second wedge-shaped teeth extending therefrom. A pair of second wedge-shaped teeth 54A, 54B also extends from the yoke 54C of each second clip 54 (see, e.g., FIG. 11E). When the wedge-shaped teeth 54A, 54B of a second clip 54 are positioned within the opening 74 of an adjacent coil 70, the yoke 54C of the second clip 54 is also arranged symmetrically about the axis of rotation 20 to form a second ring around the plurality of coils 70, spaced apart from the first ring along the axis of rotation 20. Similarly, in the embodiments of FIGS. 13A-13B, 14A-14B, and 15A-15C, the plurality of first yokes 52C and the plurality of second yokes 54C are also arranged symmetrically about the axis of rotation 20 to form spaced apart rings, with at least one pair of wedge-shaped teeth extending from each of the yokes 52C, 54C (see, e.g., FIGS. 11B and 11C).

[0092] In some embodiments, at least one first yoke, at least one second yoke, and at least one intermediate yoke are part of a stator of an electric machine. As previously described, the disclosed multi-component teeth 50 (and the first, second, and third clips forming these teeth) may be part of a stator or rotor of an electric machine. In the exemplary embodiments described herein, the multi-component teeth 50 are described as being part of a stator of an electric machine. For example, FIG. 8 illustrates an exemplary stator 30 of an electric machine having multi-component teeth 50 disposed within openings 74 of its coils 70. As seen in FIG. 8 , a plurality of first yokes 52C, a plurality of second yokes 54C, and a plurality of intermediate yokes 56C are disposed about the rotational axis 20. Collectively, each of these yokes 52C, 54C, and 56C forms axially spaced rings around the plurality of coils 70. According to some embodiments, the electric machine further includes a rotor positioned radially inward of the stator. Radially inwardly positioned refers to closer to the axis of rotation. For example, as shown in Figure 2C, the electric machine also includes a rotor 40 positioned radially inwardly of the stator 30. The rotor 40 rotates inside the stator 30 about the axis of rotation 20.

[0093] According to some disclosed embodiments, the first, second, and intermediate wedge-shaped teeth in each coil opening collectively form a multi-component tooth extending radially of the electric machine. Radial refers to an orientation toward the central axis. As previously described, the multi-component tooth in each coil opening is formed by the wedge-shaped teeth of the first, second, and third (or intermediate) clips. For example, in the embodiment of FIGS. 8 and 10A-10B, the multi-component tooth 50 in each coil opening 74 is formed by combining the first tooth 52A and second tooth 52B of the first clip 52, the first tooth 54A and second tooth 54B of the second clip 54, and the first tooth 56A and second tooth 56B of the third clip 56. Similarly, in the embodiment of Figures 12A-13B, the multi-component tooth 50 in each coil opening 74 is formed by the tooth 52D of the first clip 52 and the tooth 54D of the second clip 54, and by the first tooth 56A and the second tooth 56B of the third clip 56. Also, in the embodiment of Figures 15A-15C, the multi-component tooth 50 is formed by the tooth 52D of the first clip, the tooth 54D of the second clip, and the tooth 56D of the third clip. As also seen in the above figures, each multi-component tooth 50 extends radially along the radial axis 90. In inner-rotor electric machines (see, e.g., Figures 2C, 8, 10A-10B, 13A-13B, 14A-14B, 15A-15C), each tooth 50 extends from the ring formed by the yokes 52C, 54C, 56C (see Figures 8, 13B, 15C) along the radial axis 90 toward the axis of rotation 20. In some embodiments, the wedge-shaped teeth forming the multi-component tooth 50 may be attached to one another (e.g., using an adhesive). In some embodiments, each multi-component tooth is shaped so that the cross-sectional areas of the multi-component tooth vary in planes perpendicular to the radial direction and the perimeter of the cross sections is substantially the same across the planes. For example, as previously described with reference to FIGS. 5A-5D , each multi-component tooth 50 is shaped so that the area (i.e., cross-sectional area) of its cross section in a plane perpendicular to the radial axis 90 varies along the radial axis 90, while the perimeter of the cross section remains substantially constant along the radial axis 90. In some embodiments, the cross-sectional area of ​​each multi-component tooth in a plane perpendicular to the radial direction increases toward the axis of rotation of the electric machine.For example, as previously described, in embodiments where the electric machine is an inner-rotor electric machine, the cross-sectional area of ​​each multi-component tooth 50 (in a plane perpendicular to the radial axis 90) may increase along the radial axis 90 in a radially inward direction toward the rotor and rotational axis 20. In some embodiments, the cross-sectional shape of each multi-component tooth in at least one of the axial or radial planes of the electric machine is trapezoidal. As previously described (e.g., with reference to FIGS. 4A and 4B ), each multi-component tooth 50 may have a trapezoidal cross-sectional shape in two mutually perpendicular planes (i.e., the axial and radial planes). In some embodiments, the cross-sectional shape of each tooth 50 in the axial and / or radial planes may be an isosceles trapezoid. As previously described, an isosceles trapezoid is a trapezoid with opposite sides of equal length.

[0094] According to some disclosed embodiments, the electric machine is a generator or an electric motor. As previously explained, the disclosed electric machines are described as electric motors, but may be electric motors or generators. An electric motor is an electric machine that converts electrical energy into mechanical energy, and a generator is an electric machine that converts mechanical energy into electrical energy. As used herein, an electric motor may be any device or apparatus that converts electrical energy into mechanical energy, and conversely, a generator may be any device or apparatus that converts mechanical energy into electrical energy.

[0095] Because many components fit together to form an electric machine, manufacturing tolerances may be included in the dimensions of the components to ensure that all components fit well together. Including manufacturing tolerances may allow the electric machine to be manufactured efficiently and economically while still meeting required design and functional specifications. In some embodiments, one or more parts of a multi-component tooth may include manufacturing tolerances to enable easy assembly of the multi-component tooth in an electromagnetic coil. For example, in some embodiments, one or more edges or sides of one or more parts forming the multi-component tooth may be tapered so that they fit together even when the dimensions of these different parts vary slightly due to, for example, manufacturing inaccuracies or imperfections. For example, if the multi-component tooth has the yoke / tooth structure described above (see, e.g., FIGS. 10A-15C ), one or more edges of the yoke / tooth structure may be tapered. By way of example, an exemplary yoke / tooth structure may include a radial taper on each tooth and an axial taper on each yoke.

[0096] According to some disclosed embodiments, each electromagnetic coil defines a trapezoidally shaped, tapered coil opening. As previously described, a trapezoid is a two-dimensional, flat, closed shape having four substantially straight sides with only one pair of parallel sides. Accordingly, a "trapezoidally shaped" opening is an opening that has a trapezoidal cross-sectional shape in at least one plane. In some embodiments, a trapezoidally shaped opening may have a trapezoidal cross-sectional shape in multiple planes, for example, in two mutually perpendicular planes. The term "taper" refers to a variation (e.g., narrowing or widening) in a dimension (e.g., length, width, or any other measurable dimension) of an object or a slope of the surface of an object in a certain direction. For example, a taper may refer to a narrowing of a dimension along a certain direction or a slope of a surface in that direction. Generally, a taper refers to a variation of a dimension or a slope of a surface in any direction over any length. In some embodiments, the object may have a varying dimension or a sloping surface from one end to the other (e.g., the opposite end). In some embodiments, the object may have a varying dimension or a sloping surface in a stepwise fashion.

[0097] As previously described and illustrated, an electric machine of the present disclosure may include a plurality of electromagnetic coils 70 (see, e.g., FIGS. 8-10B, 13A-15C). These coils 70 may be arranged symmetrically about the axis of rotation or axis of rotation 20 of the electric machine. In some embodiments, each coil 70 may include a winding of an electrical conductor (e.g., copper wire or another configuration of electrical conductors) defining a coil opening 74 and may extend from a first end 76 to a second end 78 (see, e.g., FIGS. 9A-9C). A multi-component tooth 50 (e.g., of the stator 30) may be disposed within each opening 74, and each opening 74 may extend along a radial axis 90 of the electric machine (see, e.g., FIGS. 8, 10B, 13A-15C). As previously described, each multi-component tooth 50 may have a trapezoidal cross-sectional shape in both the axial plane 22 (see, e.g., FIGS. 2A, 2C, and 5A) and the radial plane 24 (see, e.g., FIG. 2B), and a rectangular cross-sectional shape in a plane perpendicular to the radial axis 90 (see, e.g., FIGS. 5A-5D). In some embodiments, each multi-component tooth 50 may be closely disposed within an opening 74 of the coil 70, such that the coil opening 74 has a shape similar to the shape of the tooth 50 therein (see, e.g., FIGS. 8, 10B, and 13A-15C). In other words, the opening 74 of each coil 70 may be a non-uniform trapezoidal cavity corresponding to the shape of the tooth received therein.

[0098] As previously described, the length (l) and width (w) of each tooth 50 may vary radially along the radial axis 90 (see, e.g., FIGS. 4A and 4B). For example, for both outer rotor electric machines (see, e.g., FIG. 4A) and inner rotor electric machines (see, e.g., FIG. 4B), the length (l) may increase and the width (w) may decrease radially toward the rotational axis 20 of the electric machine. The length and width of the coil opening 74 receiving each tooth 50 may similarly vary radially (e.g., along the radial axis 90). In other words, if the coils 74 are symmetrically positioned about the rotational axis 20, the length of the coil opening 74 may increase and the width of the coil opening 74 may decrease radially toward the rotational axis 20 (e.g., along the radial axis 90). Thus, a pair of opposing sides of opening 74 that define its length (e.g., the top and bottom surfaces of opening 74) and a pair of opposing sides of opening 74 that define its width (e.g., the left and right sides of opening 74) are both tapered. For example, the opposing sides of opening 74 that define its length are tapered, so that opening 74 becomes larger (lengthwise) toward rotation axis 20, and the opposing sides of opening 74 that define its width are tapered, so that opening 74 becomes smaller (widthwise) toward rotation axis 20.

[0099] According to some disclosed embodiments, a plurality of electromagnetic coils are arranged circumferentially about the axis of rotation of the electric machine. Circumferential arrangement refers to a pattern or configuration in which objects or elements (in this case, the coils) are positioned around the circumference or periphery of a circle or circular shape. As previously described and illustrated, when an electric machine operates, its rotor 40 and the shaft 16 coupled thereto rotate, and the axis about which the rotor 40 and shaft 16 rotate is the axis of rotation 20. The coils being "circumferentially" arranged about the axis of rotation indicates that they are arranged to surround or encircle the axis of rotation. For example, the coils may form a substantially circular array about the axis of rotation. In some embodiments, the circumferentially arranged coils may be positioned at or near the circumference of an imaginary circle formed around the axis of rotation. 8 and 12A-15C, multiple electromagnetic coils 70 may be arranged circumferentially about the rotational axis 20, with the opening 74 of each coil 70 extending along the radial axis 90 of the electric machine. In some embodiments, the coils 70 may be arranged symmetrically about the rotational axis 20, with each coil 70 being equally spaced (e.g., radially) from the rotational axis 20.

[0100] Some disclosed embodiments may include multiple yokes, each extending in an axial direction. As used herein, "axial direction" refers to the direction of the rotational axis of the electric machine. This direction may also be referred to as the longitudinal direction of the electric machine. Thus, the yokes (as described above) may extend in the longitudinal direction of the electric machine. For example, the axial direction may be a direction parallel to the rotational axis 20 (see, e.g., Figures 2A, 2C, 8, 11A-11E, and 12A-15C). For example, referring to Figure 10A, the first clip 52, the second clip 54, and the third clip 56 (or spacers) each include a yoke. For example, the first clip 52 includes a yoke 52C, the second clip 54 includes a yoke 54C, and the third clip 56 includes a yoke 56C. When these spacers or clips (52, 54, 56) are assembled in an electric machine (see, e.g., FIGS. 10B, 13A-15C), the yokes (52C, 54C, 56C) of each spacer cooperate (or collectively) to form a ring around the axis of rotation 20. FIG. 16A shows (a portion of) another embodiment of an electric machine in which multiple coils 70 are arranged circumferentially and symmetrically about the axis of rotation 20. For example, similar to the embodiments discussed above with reference to FIGS. 8, 10A-10B, and 13A-15C, a multi-component tooth 50 is positioned within each opening 74 of the coils 70. In the embodiment of FIG. 16A, the multi-component tooth 50 is formed by a pair of shims 58 positioned on axially opposite sides of an intermediate tooth 56D of the spacer 56.

[0101] 17A-17C are perspective views of an exemplary spacer 56 and an exemplary shim 58 of FIG. 16A. As best seen in FIG. 17A, the spacer 56 includes a yoke 56C from which an intermediate tooth 56D projects. While the embodiment of FIG. 17A shows a single tooth 56D projecting from the yoke 56C, this is exemplary only. For example, as discussed with reference to FIGS. 12A-12D, in some embodiments, multiple teeth (56D, 56A, 56B, 56A', 56B') project radially from the yoke 56C. When the intermediate tooth 56D of each spacer 56 is positioned within the opening 74 of each coil 70 (see, for example, FIGS. 16A-16B), the yoke 56C extends axially (i.e., along the rotation axis 20). In the radial plane, the yokes 56C of the spacers 56 are arc-shaped, such that the yokes 56C of adjacent spacers 56 collectively form a circumferential ring about the rotational axis 20 around the plurality of coils 70. For example, as also shown in Figures 10B and 13A-15C, the clip or spacer yokes (e.g., yokes 52C, 54C, 56C) of these embodiments are also arc-shaped in the circumferential direction (e.g., around the rotational axis 20) and extend axially.

[0102] According to some disclosed embodiments, at least one of the plurality of yokes is tapered in the axial direction. As previously explained, tapering in the axial direction indicates that the dimension of the yoke varies (e.g., narrows) or the surface of the yoke is tapered in the axial direction. In some embodiments, the dimension may vary or the surface may be tapered from one end of the yoke to the other (e.g., the opposite end). In some embodiments, the variation may be gradual. FIGS. 18A and 18B illustrate the arrangement of adjacent yokes 56C of spacer 56. As best seen in FIGS. 16B and 18A-18B, yoke 56C of spacer 56 tapers in the axial direction (i.e., along rotation axis 20). For example, in the axial direction, the width (w a ) is the width (w b ) is larger than the width wa From width w b In some embodiments, each yoke of the plurality of yokes is tapered along two edges in the axial direction, such that one side of the yoke is wider than the other side of the yoke. For example, multiple surfaces or edges of spacer 56 may be tapered (see, e.g., FIG. 17A). As best seen in FIGS. 17A and 18A, opposing edges 57D, 57E ​​of yoke 56C in the circumferential direction may be tapered, such that the width (w a ) is the width at the opposite end of the shaft (w b ) is greater than the width w . According to some disclosed embodiments, the wide side of each yoke is disposed adjacent to the narrower side of the adjacent yoke. With such adjacent placement, the wide side of a first yoke is adjacent to the narrower side of a second yoke, while the narrow side of the first yoke is adjacent to the wide side of the second yoke. As previously described, when the intermediate teeth 56D of a spacer 56 are positioned within the openings 74 of adjacent coils 70, the yokes 56C of adjacent spacers 56 cooperate to form a ring around the rotation axis 20. In this configuration, as best seen in FIGS. 18A-18B, the wider side (e.g., width w ) of the yoke 56C is positioned adjacent to the narrower side of the adjacent yoke. a ) is spaced apart from the narrower side (e.g., width w b The side having the .lambda.

[0103] According to some embodiments, the outer surfaces of the yokes cooperate to form a cylindrical shape. Cooperating to form a cylindrical shape refers to a situation in which a cylindrical shape is apparent when viewed as a whole. For example, in some embodiments, when the intermediate tooth 56D of a spacer 56 is positioned within the opening 74 of an adjacent coil 70, the radially outermost surfaces 57F of the yokes 56C cooperate to form a cylindrical shape (see, for example, FIG. 18B ). In some embodiments, the spacers 56 may be similarly (or identically) shaped components. However, due to possible dimensional variations during manufacturing, dimensional variations may exist between different spacers 56. Due to this possible dimensional variation, in some embodiments, the radially outermost surfaces 57F of the yokes may cooperate to form a substantially cylindrical shape. The tapered yokes of the present disclosure may enable stator assembly while maintaining critical dimensions of the electric machine, even when there are dimensional variations in the spacers 56. According to some embodiments, the edge of at least one yoke among the plurality of yokes is not aligned with the edge of an adjacent yoke. "Misaligned" refers to at least one yoke edge not being aligned with an adjacent yoke edge. For example, as shown in FIG. 16B, due to dimensional variations among different spacers 56, one end (or edge) of a yoke 56C may be axially misaligned with (e.g., axially spaced apart from) the corresponding end (or edge) of an adjacent spacer 56. However, in some embodiments, the yokes 56C of adjacent yokes 56C may be substantially axially aligned.

[0104] According to some disclosed embodiments, the electric machine may include a plurality of teeth, where at least one tooth of the plurality of teeth extends from each of a plurality of yokes. The term "teeth" (and its singular form "tooth") may be interpreted in accordance with the above explanation of this term. For example, a tooth refers to a protrusion or projection. Although not required, in some embodiments, one or more teeth may protrude or extend from the body. For example, as shown in FIGS. 8, 10A-10B, 11A-11E, and 12A-18B, the disclosed electric machine includes a plurality of teeth (e.g., teeth 52A, 52B, 52D, 54A, 54B, 54D, 56A, 56B, and 56D). In some embodiments, one or more of these teeth may extend from the yoke. For example, in the spacer embodiments shown in FIGS. 11A-11C and 15A-15C, more than two teeth (52D, 54D) extend from each yoke (52C, 54C); in the embodiments shown in FIGS. 10A-10B, 11E, 12B-12D, 13A-13B, and 15A-15C, two teeth (e.g., teeth 52A, 52B, etc.) extend from each yoke (e.g., 52C); and in the embodiments shown in FIGS. 11D, 12A, 14A-14B, 16A, and 17A, a single tooth (e.g., tooth 56D) extends from each yoke (e.g., yoke 56C). Each of these teeth may extend radially (along radial axis 90) from its corresponding yoke into opening 74 of coil 70. In some disclosed embodiments, only one of the teeth extends from each of the yokes. "Only one extending tooth" in this example refers to a one-to-one relationship between the yoke and the tooth. For example, in the embodiments shown in Figures 12A, 14A-14D, and 17A, only a single tooth 56D extends from each yoke 56C. In some disclosed embodiments, two of the teeth extend from at least one yoke. Two teeth extending from at least one yoke refers to a situation where there is a two-to-one relationship between the tooth and at least one of the yokes. For example, in the embodiments of Figures 12B and 15A-15C, two teeth 56D extend from the yoke 56C.

[0105] In some disclosed embodiments, each of the plurality of teeth tapers radially, allowing the plurality of teeth to fit within a corresponding trapezoidally shaped, tapered coil opening. "Radial" refers to a direction toward the central axis. For example, in FIGS. 4A and 4B , the tooth tapers as it extends along the radial axis 90 of the electric machine. As previously described, each tooth of the plurality of multi-component teeth 50 tapers radially (i.e., along the radial axis 90). For example, with reference to FIGS. 4A and 4B , the width of an exemplary multi-component tooth 50 increases from w1 to w2, while its height decreases radially outward from the rotational axis 20 along the radial axis 90 from l1 to l2. Thus, the width of the tooth 50 tapers radially inward (e.g., toward the rotational axis 20), and its height tapers radially outward (e.g., away from the rotational axis 20). Thus, both the width and height of the tooth 50 taper radially. Because the height (l) of the tooth 50 decreases from l1 to l2 in the radially outward direction, the top and bottom surfaces (see FIGS. 4A and 4B) are oblique (or tilted) relative to the radial plane 24. Also, because the width (w) of the tooth 50 increases from w1 to w2 in the radially outward direction, the two sides of the tooth 50 are also tilted relative to the axial plane 22. Each multi-piece tooth 50 is made up of multiple components. For example, with reference to FIGS. 16A and 17A-17C, the multi-piece tooth 50 (see FIG. 16A) is formed by a pair of shims 58 positioned on axially opposite sides of the middle tooth 56D of the spacer 56 (see, e.g., FIGS. 17A-17C). The components of the multi-piece tooth 50 (e.g., the tooth 56D and the shims 58) may also be radially tapered. For example, the widths of both the tooth 56D and the shims 58 increase in the radially outward direction (e.g., away from the axis of rotation 20). That is, the widths of tooth 56D and shim 58 taper toward rotation axis 20. As a result of the varying widths, two side surfaces 57B and 57C of tooth 56D (see FIG. 17A) are angled radially inward (e.g., toward rotation axis 20) toward radial axis 90. Similarly, the height of shim 58 increases toward rotation axis 20 (see FIGS. 17B-17C). Thus, the height of shim 58 tapers away from rotation axis 20.For example, as described with reference to Figures 5A-5D, tooth 56D and a pair of shims 58 positioned on axially opposing surfaces of tooth 56D collectively form a multi-component tooth 50 that may have a trapezoidal cross-sectional shape in both axial plane 22 (see, e.g., Figures 2A, 2C, and 5A) and radial plane 24 (see, e.g., Figure 2B) and a rectangular cross-sectional shape in a plane perpendicular to radial axis 90 (see, e.g., Figures 5A-5D). As previously described, each multi-component tooth 50 may be closely disposed within coil opening 74 (see, e.g., Figures 8, 10B, and 13A-15C) and may have a shape similar to that opening. In other words, each multi-component tooth 50 may be shaped to fit within a corresponding trapezoidally shaped tapered coil opening 74.

[0106] According to some embodiments, each tooth of the plurality of teeth is tapered in four planes. Each surface may be defined by a plane. When a tooth is tapered in four planes, four surfaces are tapered. For example, as previously described with reference to FIGS. 4A and 4B, the height (l) of the multi-piece tooth 50 decreases from l1 to l2 in the radially outward direction, so that the top and bottom surfaces (see FIGS. 4A and 4B) are oblique to the radial plane 24, and the width (w) of the tooth 50 increases from w1 to w2 in the radially outward direction, so that two side surfaces of the tooth 50 are oblique to the axial plane 22. Thus, the tooth 50 is tapered in four planes (e.g., the top surface, the bottom surface, and two side surfaces). In some embodiments, each tooth of the plurality of teeth is tapered in two planes, and the electric machine further includes a pair of shims disposed on opposite sides of each tooth of the plurality of teeth. A "shim" is a piece of material inserted or placed between two objects or surfaces to adjust the fit, alignment, or clearance between them. Shims may be positioned on opposite sides of each tooth for the purpose of adjusting the fit, alignment, and / or clearance. As described above, the top surface, bottom surface, and two side surfaces of each multi-component tooth 50 are tapered. The top and bottom surfaces are tapered relative to the radial plane 24, and the two side surfaces are tapered relative to the axial plane 22 (see, e.g., FIG. 4A). In some embodiments, the shim may be tapered or wedge-shaped. For example, referring to FIGS. 16A and 17A-17C, the multi-component tooth 50 (see FIG. 16A) is formed by a pair of shims 58 positioned on axially opposite sides (e.g., top and bottom) of the intermediate tooth 56D of the spacer 56 (see, e.g., FIGS. 17A-17C). Here, shim 58 may fill the space between the top and bottom surfaces of tooth 56D and the axially opposing surfaces of coil opening 74 (see, e.g., FIG. 16A). As another example, in the embodiment shown in, e.g., FIGS. 10A-10B and 13A-15C, a pair of shims (see, e.g., FIGS. 11A-11E) in the form of wedge-shaped teeth (e.g., teeth 52A, 52B, 52D, 54A, 54B, 54D) are positioned on the top and bottom surfaces of the intermediate teeth.In some embodiments, at least three sides of each shim are tapered. For example, referring to FIG. 17C, the top surface 59A, bottom surface 59B, and two opposing side surfaces of shim 58 are tapered due to the radial changes in width and height of shim 58. Similarly, for example, the two pairs of opposing sides of the shim in the embodiments of FIGS. 10A-10B and 13A-15C are also tapered (see, e.g., FIGS. 11A-11E). In some embodiments, the two tapered planes are transverse to each other. Transverse planes mean that they intersect each other as they extend (e.g., the planes of the tapered surfaces are not parallel to each other). As explained above, the top and bottom surfaces of multi-component tooth 50 are tapered relative to radial plane 24, and its two side surfaces are tapered relative to axial plane 22, which is transverse to radial plane 24 (see, e.g., FIG. 4A).

[0107] According to some embodiments, the disclosed electric machine includes a rotor positioned radially inward of a plurality of electromagnetic coils. Also, in some embodiments, the disclosed electric machine includes a rotor positioned radially outward of a plurality of electromagnetic coils. Inwardly positioned refers to being closer to the central axis, and outwardly positioned refers to being further away from the central axis. As previously discussed, aspects of the disclosure may be applicable to both inner-rotor and outer-rotor electric machines. As shown in FIG. 2C, an inner-rotor electric machine 10A includes a rotor 40 positioned radially inward of a stator 30. Also, as shown in FIG. 2A, in an outer-rotor electric machine 10, the rotor 40 is positioned radially outward of the stator 30. In both embodiments, the rotor 40 rotates about a rotational axis 20 during operation.

[0108] In some embodiments, the teeth are formed from an SMC material, and in some embodiments, the teeth are formed from laminated steel. Just as the clip can be made from an SMC material or laminated steel as described above, the teeth may be similarly constructed, or may be constructed from any other suitable material. According to some embodiments, the cross-sectional shape of each multi-component tooth in at least one of the axial or radial planes of the electric machine is trapezoidal. As previously described, the cross-sectional shape of each multi-component tooth 50 in both the axial plane 22 and the radial plane 24 is trapezoidal (see, e.g., FIGS. 2A-2C ). In some embodiments, the cross-sectional shape in one or both of the axial plane 22 and the radial plane 24 may be an isosceles trapezoid.

[0109] According to some embodiments, the teeth in each coil opening combine to form a wedge-shaped multi-component tooth that extends in a radial direction of the electric machine and is shaped such that the cross-sectional areas of the multi-component tooth vary in planes perpendicular to the radial direction and the perimeter of the cross-sections is substantially the same across the planes. The term "wedge-shaped" may be interpreted as previously described and illustrated. In this example, two or more elements or pieces of material combine to form the wedge-shaped multi-component tooth. For example, as previously described and illustrated in, e.g., FIGS. 4A and 4B , each multi-component tooth 50 of the disclosed electric machines may be wedge-shaped and extend in a radial direction (along a radial axis 90) of the electric machine. As previously described (e.g., with reference to FIGS. 5A-5D ), the perimeter of each tooth 50 in the radial direction along the radial axis 90 may be substantially constant, while the cross-sectional area of ​​each tooth 50 in the radial direction may vary. In some embodiments, the cross-sectional area of ​​each multi-piece tooth in a plane perpendicular to the radial direction increases toward the axis of rotation of the electric machine. In embodiments of electric machines having an inner rotor 40 and an outer stator 30 (see, e.g., FIGS. 2C and 3A ), the cross-sectional area may increase in a radially inward direction toward the axis of rotation 20. In some embodiments, the cross-sectional area may increase monotonically in a radially inward direction. In some embodiments, the taper of the outer surfaces (e.g., side, top, and bottom surfaces) of each multi-piece tooth 50 may be such that the rate of change of the cross-sectional area in the radial direction may be constant. For example, in some embodiments, the rate of increase of the cross-sectional area in the radially inward direction may be constant.

[0110] Electric machines of the present disclosure may be air-cooled or liquid-cooled. During operation of an electric machine, components of the electric machine (e.g., coils 70, etc.) may generate heat. The generated heat may increase the temperature of components of the electric machine (e.g., teeth 50, stator 30, etc.). In air-cooled electric machines, the generated heat may be removed using ambient air or atmosphere to maintain the temperature of the electric machine within acceptable levels. In liquid-cooled electric machines, at least a portion of the generated heat may be removed by a coolant. In some embodiments of an electric machine, a portion of the generated heat may be removed by the atmosphere, and a portion of the heat may be removed by a coolant circulating through the electric machine.

[0111] According to some embodiments, an air-coolable electric machine may include a stator and a rotor. An "air-coolable" electric machine refers to a motor or generator in which at least a portion of the electric machine can be cooled using airflow. For example, an electric machine that at least partially uses air as a cooling medium is an air-cooled electric machine. As previously described and illustrated, the stator is the stationary component, and the rotor is the rotatable component of the electric machine. In an inner-rotor electric machine 10A, the rotor 40 may be positioned radially inward of the stator 30 (see, e.g., FIG. 2C ), while in an outer-rotor electric machine 10 (see, e.g., FIGS. 2A-2B ), the rotor 40 may be positioned radially outward of the stator 30. In some embodiments, the electric machine may also include a heat-dissipating plate. "Heat dissipation" is the movement or transfer of heat from a hotter location to a cooler location. Because materials such as metals are thermally conductive, plates may be used to remove heat (dissipate heat) from portions of the electric machine. For example, heat may be dissipated from its source through such a plate into the surrounding environment. Thus, a heat dissipation plate is a component physically positioned in the path of such heat transfer. For example, heat may be transferred from a hotter location to a cooler location through the heat dissipation plate. For example, the heat dissipation plate may dissipate heat from the source to the atmosphere. The heat dissipation plate may be a single component or a combination of multiple components working together. In some embodiments, the heat dissipation plate is formed from aluminum. In general, the heat dissipation plate may be made from any thermally conductive material (e.g., one or more) for conducting and removing heat from a heat source. For example, in some embodiments, the heat dissipation plate may be a one-piece or single component formed from aluminum.

[0112] FIG. 19 illustrates an exemplary electric machine 10′ with a heat-dissipating plate 100 attached to its housing 12. The heat-dissipating plate 100 may help dissipate heat generated by the electric machine (e.g., components within the housing 12) to the atmosphere. In some embodiments, the housing 12 may be thermally connected to the heat-dissipating plate 100, such that heat can also be dissipated through the housing 12. The housing 12 may be made of a thermally conductive material and may include ribs to increase its heat transfer surface. FIGS. 20A-20C and 22 illustrate some exemplary embodiments of the heat-dissipating plate 100 separated from the electric machine. The heat-dissipating plate 100 may generally have a plate-like or disk-like configuration with a thickness less than its radius. In some embodiments, the heat-dissipating plate 100 may have a circular shape when viewed along the rotation axis 20 (e.g., in a radial plane), as shown in FIGS. 20A-20C and 22.

[0113] According to some embodiments, the heat-dissipating plate includes a first side disposed in thermal communication with the stator. "First side" may refer to any side or surface of the heat-dissipating plate configured to face the stator. "Thermal communication" with the stator refers to spatial proximity between the heat-dissipating plate and the stator such that good heat transfer occurs between them. In some embodiments, when two bodies are in thermal communication or thermally connected, heat transfer between the two bodies occurs via a conductive heat transfer mechanism. That is, the two bodies may be in contact (either direct physical contact or contact via a thermal interface material between the two bodies). For example, in some embodiments, when two bodies are in thermal communication, a surface of one body may be in direct contact with a surface of the other body. In some embodiments, when two bodies are in thermal communication, a surface of one body may be in contact with a surface of the other body through a thermal interface material (e.g., thermally conductive grease, ice packs, or another heat medium) between the two surfaces. Generally, the first side of the heat dissipation plate may be positioned to contact any component or portion of the stator. For example, with reference to FIGS. 19 and 22 , the heat dissipation plate 100 includes a first side 104 facing the interior of the housing 12. The first side 104 may include regions or features (not shown in FIGS. 19 and 22 ) configured to contact one or more portions of the stator 30. For example, in the embodiment of FIG. 22 , the first side 104 includes an annular groove 106 configured to be in thermal communication with the outer surface of each coil 70 of the plurality of coils 70. The annular groove 106 may extend around the rotating shaft 20 and may be shaped and positioned to receive the coil 70 therein when the electric machine is assembled. In some embodiments, the outer surface of the coil 70 may contact the surface of the groove 106 (e.g., directly or through an interface material) to transfer heat from the coil 70 to the heat dissipation plate 100.

[0114] In some embodiments, each coil 70 of the multiple electromagnetic coils and / or other portions of the stator 30 (e.g., the stator core) may contact the heat dissipation plate 100 directly or through a thermally conductive (or interface) material disposed therebetween. The thermally conductive material may be any material that improves the transfer of heat between boundary surfaces. The thickness of the thermally conductive material and its thermal conductivity may affect the heat transfer through the material. Therefore, in some embodiments, a thin layer of the thermally conductive material may be used to reduce its thermal resistance. The thickness of the thermally conductive material depends on the application. In applications where the thermal conductivity of the thermally conductive material is high, the thickness of the thermally conductive material may be greater. In some embodiments, the heat dissipation plate 100 may include a cylindrical hub 150 extending from the first side 104. The cylindrical hub 150 may extend around the rotation axis 20 and may be made of a thermally conductive material.

[0115] In some embodiments, the heat dissipation plate may have a central opening therein and an outer periphery. "Outer periphery" refers to the outer edge of a body boundary or structure. Thus, outer periphery refers to the outer edge of the heat dissipation plate. "Central opening" in this context refers to a hole or gap located at the center of the heat dissipation plate. In embodiments in which the heat dissipation plate 100 has a circular shape, the outer periphery refers to the circumference of the circular plate, and the central opening refers to an opening at the center of the circular plate. For example, the heat dissipation plate 100 includes an outer periphery (e.g., a circular periphery) and a central opening 140. In some embodiments, the central opening 140 may allow ambient air or atmosphere to flow through it into the electric machine housing 12. Additionally or alternatively, in some embodiments, the central opening 140 may allow the shaft 16 of the electric machine 10' to extend therethrough.

[0116] According to some embodiments, a plurality of circumferentially distributed Y-shaped or ψ-shaped cooling fins may extend from a second side of the heat dissipation plate opposite the first side. Generally, the "second side" may be any side or surface of the heat dissipation plate different from the first side. In some embodiments, the second side may be a surface of the heat dissipation plate opposite the first side of the heat dissipation plate that is in thermal communication with the stator. A "cooling fin" refers to a structure extending from a surface (in this case, from the second side) to increase the rate of heat transfer between (e.g., from or to) the surface and the environment, for example, by increasing convection. The cooling fin increases the surface area of ​​the surface from which it extends, thereby increasing heat transfer from the surface. The cooling fin may be made of any thermally conductive material. In some embodiments, the cooling fin may be made of the same material as the object from which it extends. For example, if the heat dissipation plate is made of aluminum, the structure forming the cooling fin may also be made of aluminum. In general, the cooling fins may have any shape and configuration. In some embodiments, the cooling fins may include plate-like structures protruding from the second side of the heat dissipation plate. The spacing between the cooling fins may allow ambient air to flow through these spaces, creating turbulence that may help break up any boundary layer that may exist on the surface, thereby increasing the convective heat transfer coefficient of the surface. In some embodiments, the cooling fins may be generally Y- or ψ-shaped.

[0117] It should be noted that the symbols (Y and ψ) only indicate the approximate shape of the cooling fins. For example, FIG. 21A illustrates an exemplary cooling fin 100 having a Y-shape, and FIG. 21B illustrates an exemplary cooling fin 100' having a ψ-shape. A "circumferentially" distributed cooling fin indicates that the cooling fins are arranged in a generally circular pattern on the second side. For example, as shown in FIGS. 19, 20A-20C, and 22, the cooling fins (100, 100') may be arranged to form a substantially circular array, for example, around the central opening 140 and rotational axis 20 of the electric machine 10'. In some embodiments, the Y- or ψ-shaped cooling fins are symmetrically arranged about the central opening. A symmetrical arrangement in this context refers to a balanced or harmonious distribution. For example, the distribution pattern may provide symmetry. For example, as shown in FIGS. 19, 20A-20C, and 22, the Y-shaped cooling fins 110 and ψ-shaped cooling fins 110' are symmetrically positioned about the central opening 140 and the axis of rotation 20. In some embodiments, the Y-shaped or ψ-shaped cooling fins are positioned to radiate outward from the center of the cooling plate. Radiating outward refers to the situation where the cooling fins extend in a generally elongated direction from an inner location on the plate toward the outer edge of the plate. For example, the Y-shaped cooling fins 110 and ψ-shaped cooling fins 110' may be symmetrically positioned about the axis of rotation 20 such that imaginary lines extending from the linear segments 116 of these cooling fins (see, e.g., FIGS. 21A and 21B) intersect at the axis of rotation 20.

[0118] In some embodiments, each cooling fin includes a radially extending leg portion and a V-shaped or ε-shaped deflector portion, where each V-shaped or ε-shaped deflector portion faces the outer periphery of the heat dissipation plate to deflect a first portion of the airflow outward, and each radially extending leg portion is positioned to direct a portion of the airflow inward toward the central opening. A leg refers to an elongated or linear structure, and a deflector portion includes a portion branching off from the leg. As shown by way of example in FIG. 21A , the illustrated Y-shaped cooling fin 110 includes a pair of linear segments 112 arranged in a V shape to form a deflector portion extending from a distal end 116B of the linear (or leg) segment 116. When the heat dissipation plate 100 is assembled onto the electric machine 10′ (see FIG. 19 ), the leg segments 116 may extend along the radial axis 90 from a proximal end 116A positioned closer to the rotation axis 20 and a distal end 116B positioned further away from the rotation axis 20. In this configuration, the open end of the V-shaped segment 112 (or V-shaped deflector) may face the outer periphery of the heat dissipation plate 100. While the segments 112 and 116 have been described as being straight, this is exemplary only. In some embodiments, one or both of the segments 112, 116 may be curved. For example, in some embodiments, the segment 112 may be curved (e.g., away from the radial axis 90 to have a U-shaped, rotated C-shaped, or cup-shaped deflector portion) and the segment 116 may be straight. The ψ-shaped cooling fin 110′ shown in FIG. 21B includes a pair of linear segments 112 arranged in a V-shape extending from a distal end 116B of a linear segment 116 (similar to the Y-shaped cooling fin of FIG. 21A ), and an additional linear segment 114 extending from the distal end 116B between the pair of linear segments 112. In some embodiments, some or all of the segments 112, 114, 116 may be curved. For example, in some embodiments, segment 112 may be curved (e.g., having a U-shape or cup shape) and segments 114, 116 may be straight, such that the distal portion of the ψ-shaped cooling fin 110′ forms a deflector portion having an approximate ε-shape.As shown using arrows in FIG. 20B , each V-shaped deflector portion of the Y-shaped cooling fin 100 (and each ε-shaped deflector portion of the ψ-shaped cooling fin 100′) faces the outer periphery of the heat dissipation plate and deflects a portion of the airflow outward (e.g., away from the central opening 140 and the rotation axis 20), and each radially extending leg segment 116 directs a portion of the airflow inward (e.g., toward the central opening 140 and the rotation axis 20).

[0119] 19, 20A, 20B, and 22 illustrate an exemplary heat-dissipating plate 100 having Y-shaped cooling fins 110 extending from a second side 102 of the heat-dissipating plate 100. FIG. 20C is a schematic diagram of the heat-dissipating plate 100 having ψ-shaped cooling fins 100′. As can be seen in these figures, the Y-shaped cooling fins 110 (and ψ-shaped cooling fins 100′) may be circumferentially arranged or distributed on the heat-dissipating plate 100 with their linear segments 116 extending along the radial axis 90. The open ends of the V-shaped deflector portions and the ε-shaped deflector portions of the Y-shaped cooling fins 110 may face the circular outer periphery of the heat-dissipating plate 100. In some embodiments, the distal-most ends of the V-shaped and ε-shaped segments may extend to the outer periphery of the heat-dissipating plate 100, as shown in these figures. In some embodiments, as shown in FIG. 20C, the Y-shaped cooling fins 110 of the heat-dissipating plate 100 can be replaced with ψ-shaped cooling fins 110'.

[0120] According to some embodiments, the second side of the heat dissipation plate further includes non-Y-shaped and non-ψ-shaped cooling fins disposed between adjacent Y-shaped or ψ-shaped cooling fins. The non-Y-shaped and non-ψ-shaped cooling fins are cooling fins having a shape different from the Y-shaped and ψ-shaped cooling fins described above. They may include cooling fins of any shape different from the Y-shaped and ψ-shaped cooling fins. For example, as best seen in FIGS. 20B and 20C , in some embodiments, non-Y-shaped and non-ψ-shaped cooling fins in the form of cooling fin 120 may be disposed between adjacent Y-shaped or ψ-shaped cooling fins. Although not required, in some embodiments, all of the non-Y-shaped and non-ψ-shaped cooling fins may have the same shape. In some embodiments, the non-Y-shaped and non-ψ-shaped cooling fins are linear cooling fins extending from the periphery of the heat dissipation plate toward the central opening. 20B and 20C, the cooling fins 120 are linear cooling fins that extend from the periphery of the heat dissipation plate 100 toward the central opening 140 (and the rotation axis 20). As shown in these figures, in some embodiments, the cooling fins 120 may extend along the radial axis 90 of the electric machine.

[0121] According to some embodiments, the second side of the heat-dissipating plate further includes a plurality of cooling pins disposed radially inward of the Y-shaped or ψ-shaped cooling fins. The cooling pins are cylindrical cooling fins. The pins may have any cross-sectional shape (round, square, or another suitable shape). For example, as shown in FIGS. 19, 20A-20C, and 22, the second side 102 of the heat-dissipating plate 100 includes cooling pins 120 radially inward of the cooling fins 110, 110'. In some embodiments, the plurality of cooling pins are disposed at a common radial distance from the central opening. As shown in these figures, in some embodiments, the cooling pins 120 may be disposed in a circular pattern between the cooling fins 110 (or 110') and the central opening 140. In some embodiments, the plurality of cooling pins are disposed symmetrically around the central opening. For example, the cooling pins 120 may be disposed symmetrically around the central opening 140 and the rotation axis 20. In some embodiments, the plurality of cooling pins includes a first set of cooling pins positioned a first common radial distance from the central opening and a second set of cooling pins positioned a second common radial distance from the central opening. In some embodiments, a single circular array of cooling pins 120 may be provided (see, e.g., FIG. 20A), while in some embodiments, multiple circular arrays of cooling pins 120 may be positioned between the cooling fins 110, 110' and the central opening 140 (see, e.g., FIGS. 19, 20B, 20C).

[0122] According to some embodiments, the heat dissipation plate further includes a plurality of cavities extending from the second side to the first side, the plurality of cavities being symmetrically positioned about the central opening. A cavity refers to a recess, indentation, or opening. For example, as seen in FIGS. 20A and 20B , in some embodiments, cavities 142 may extend through the heat dissipation plate 100. In some embodiments, these cavities may serve as attachment points for components of the electric machine. In some embodiments, these cavities 142 may serve as air holes. Generally, any number of cavities (3, 4, 5, or any other number) may be provided. In some embodiments, these cavities 142 may be symmetrically disposed about the central opening 140 and positioned between the sets of cooling fins 110, 110′. In some embodiments, the electric machine is a generator, and in some embodiments, the electric machine is an electric motor. As previously described, the electric machine 10′ may be an electric motor or a generator.

[0123] While Figures 19-22 show various examples of fins, deflectors, pins, and cavities, it will be understood that the arrangement of such structures and their symmetry are provided by way of example only, and that other arrangements of the disclosed elements or variations thereof may be employed within the scope and spirit of the present disclosure.

[0124] In embodiments where the coil 70 and / or other parts of the stator 30 are in thermal contact with the heat dissipation plate 100 due to direct physical contact, heat from the coil 70 (and / or other stator components) may be conducted directly into the heat dissipation plate 100. In embodiments where a thermally conductive material is provided between mating parts, heat may be conducted through the thermally conductive material. Thus, thermal communication between the coil 70 and / or other stator components and the heat dissipation plate 100 provides a direct path for heat to conduct out of the stator 30. Airflow across the cooling fins 110 or 110′ and pins 120 on the opposite side of the heat dissipation plate 100 may then remove heat from the heat dissipation plate 100. Thus, the heat dissipation plate 100 may act as an air-cooled radiator for electrical machines. The Y-shaped or ψ-shaped cooling fins 110, 110' improve the air flow over the heat dissipation plate 100 and the removal of heat therefrom.

[0125] 23A-23I, an exemplary method for assembling a stator for an electric machine will now be described. For brevity, the exemplary method is described using only a partial configuration of components (e.g., first clip 52, second clip 54, and third clip 56). However, this is merely exemplary, and the stator may be similarly assembled using any of the disclosed configurations of components (e.g., clips). Multiple electromagnetic coils 70 may be provided for placement on the composite teeth of the stator. These coils may be manufactured, obtained, or provided for assembly in any manner. As previously described, each of these coils may have an opening 74. When the stator is assembled (see, e.g., FIG. 8), the coil opening 74 may have a length extending along the rotational axis 20 and a depth extending along the radial axis 90 (see, e.g., FIG. 9A).

[0126] The shape of the coil opening 74 may correspond to (e.g., may be similar to) the wedge-shaped shape of the assembled composite or multi-part tooth (see, e.g., FIGS. 10A-10B). The first clip 52 may be placed over the second clip 54, for example, as shown in FIG. 23B, such that the two clips 52, 54 are mirror images of each other with respect to a plane perpendicular to the axis of rotation 20. In other words, the first clip 52 and the second clip 54 are stacked one on top of the other. In some embodiments, the first clip 52 and the second clip 54 may be positioned near each other. Generally, the first clip 52 (having a first arcuate yoke 52C with one or more wedge-shaped teeth 52D; see FIGS. 11A-11D) and the second clip 54 (having a second arcuate yoke 54C with wedge-shaped teeth 54D; see FIGS. 11A-11D) can be positioned on top of or next to each other along the rotation axis 20 (see, for example, FIGS. 23A and 23B). When the first clip 52 and the second clip 54 are placed on top of each other (see, for example, FIG. 23B), the cross section of the combined teeth portions of the two clips 52, 54 (formed by the teeth 52D of clip 52 and the teeth 54D of clip 54) in an axial plane forms a trapezoid.

[0127] With the two clips 52, 54 placed on top of (or near) each other, the interdigitated teeth (i.e., teeth 52D and 54D) of the two clips 52, 54 are inserted into the opening 74 of the coil 70 (see, e.g., FIGS. 23B and 23C). When so inserted, the interdigitated teeth may fill the depth of the opening 74, with a gap along the length of the opening 74. When the teeth 52D, 54D of the clips 52, 54 are inserted into the central region of the opening 74 (see, e.g., FIG. 23C), there may be a first gap between the top of the tooth 52D of the clip 52 and the top surface of the opening 74, and a second gap between the bottom of the tooth 54D of the clip 54 and the bottom surface of the opening 74. The two clips 52, 54 with wedge-shaped teeth 52D, 54D can then be moved (or shifted) in opposite directions along the rotation axis 20 (see arrow A in FIG. 23D ) until they stop moving. That is, until the two teeth 52D, 54D press against the top and bottom surfaces of the opening 74, respectively, creating a gap between the two teeth 52D, 54D. In some embodiments, the first clip 52 and the second clip 54 can have an arcuate, semicircular configuration, as shown in FIGS. 23A-23I (see also FIGS. 11B-11C ). An adjacent tooth 56D of a third or intermediate clip or spacer 56 can then be inserted into the gap in the coil opening 74 between the first clip 52 and the second clip 54 (see, e.g., FIGS. 23E and 23F ). When inserted in this manner, one tooth 56D (of the spacer 56) fills the gap between the teeth 52D, 54D (of the first clip 52 and the second clip 54) in the coil opening 74. In some embodiments, during insertion, the tooth 56D of the spacer 56 may push and move the teeth 52D, 54D of the first clip 52 and the second clip 54 (e.g., upward and downward along the axis of rotation 20) against the inner wall of the opening 74, resulting in a tight fit of the composite tooth within the coil opening 74.

[0128] When first and second clips 52, 54 having semicircular configurations are used, two semicircular arcuate portions (or halves) of the stator may be assembled as described above (see, e.g., FIG. 23F). The two arcuate halves (each having two terminal or free ends) may then be joined together to form the ring-shaped stator 30 (see FIGS. 23F, 23G). As shown in FIGS. 23F and 23G, in some embodiments, the two arcuate halves may be joined by inserting adjacent teeth 56D of a spacer 56 into openings in each half. For example, as best seen in FIG. 23G, one tooth 56D of a spacer 56 is inserted into a coil opening 74 at one end of one semicircular half, and another tooth 56D of the same spacer 56 is inserted into a coil opening 74 at the end of the other semicircular half to connect the two ends of the two semicircular halves to each other. Another spacer 56 may be used to similarly connect the other two ends of the two semicircular halves. The two semicircular halves are connected together to form a ring-shaped stator 30. The assembled stator 30 can then be installed in the housing 12. Here, a two-toothed spacer 56 acts as a clamp to hold the two halves of the stator together before installation in the housing 12. Note that the first clip 52 and second clip 54 having the configuration shown in FIG. 11B and the spacer 56 having the configuration shown in FIG. 12B are used to illustrate the exemplary method above, but this is for illustrative purposes only. In general, any of the previously described configurations of the first clip 52 and second clip 54 (e.g., shown in FIGS. 11A-11F) and the previously described configurations of the spacer 56 (e.g., shown in FIGS. 12A-12D) can be used to assemble a stator in a similar manner.

[0129] Furthermore, the above-described embodiments of the electric machine are merely exemplary, and many variations are possible. Some possible variations are described in U.S. Patent Nos. 9,502,951, 10,056,813, and PCT Publication WO 2022 / 058939 A1 (published March 24, 2022), each of which is incorporated by reference herein in its entirety. Furthermore, although some aspects of the electric machine are described with reference to an electric machine of a particular configuration, the described aspects may be used with an electric machine having any configuration.

[0130] The following are provisions for exemplary electric machines of the present disclosure: (Article 1) a plurality of coils, wherein each coil of the plurality of coils defines a coil opening; and a plurality of U-shaped clips, each U-shaped clip having a first tooth, a second tooth, and a yoke interconnecting the first tooth and the second tooth; Equipped with wherein the first tooth of each U-shaped clip is disposed in one coil opening of the plurality of coils, the second tooth of each U-shaped clip is disposed in another coil opening of an adjacent coil, the yoke bridges two adjacent coils, and two side walls of the two adjacent coils are sandwiched between the first tooth and the second tooth of each U-shaped clip. Electrical machinery. (Article 2) 10. The electric machine of claim 1, wherein each coil opening includes a plurality of teeth arranged along a length of the opening. (Article 3) 10. The electric machine of any preceding clause, wherein one or more of the plurality of teeth fills the entire width of each opening. (Article 4) 10. The electric machine of any preceding clause, wherein a single tooth of the plurality of teeth fills the entire width of each opening. (Article 5) 10. The electric machine of claim 9, wherein the plurality of teeth includes at least upper teeth, lower teeth, and central teeth, and at least one of the upper teeth or the lower teeth fills the entire width of a respective opening and includes an arc-shaped yoke with the plurality of teeth extending therefrom. (Article 6) The electric machine of any preceding clause, wherein each coil opening includes at least one first tooth of a first group of the plurality of U-shaped clips and at least one first tooth of a second group of the plurality of U-shaped clips, the first group being different from the second group. (Article 7) The electric machine of any preceding clause, wherein the at least one first tooth of the first group has a length greater than a length of the at least one first tooth of the second group. (Article 8) The electric machine of any preceding clause, wherein at least two first teeth of the second group have a common length. (Article 9) 10. The electric machine of claim 9, wherein a group of the U-shaped clips has a first tooth disposed within the coil opening of one of the coils, and at least one U-shaped clip in the group has a wedge-shaped first tooth. (Article 10) 10. The electric machine of claim 9, wherein at least one U-shaped clip in the group has a wedge-shaped second tooth. (Article 11) 10. The electrical machine of claim 9, wherein the at least one U-shaped clip in the group is made from an SMC material. (Article 12) 10. The electric machine of any preceding clause, wherein all of the U-shaped clips in the group are made from an SMC material. (Article 13) 10. The electric machine of any preceding clause, wherein all of the U-shaped clips in the group are made from laminated steel. (Article 14) The electric machine of any preceding clause, wherein a length dimension of each wedge-shaped first tooth varies from one end of the coil opening to an opposite end of the coil opening. (Article 15) 10. The electric machine of any preceding clause, wherein the plurality of yokes cooperate to form a ring. (Article 16) The electric machine of any preceding clause, wherein the plurality of yokes cooperate to form a first ring and a second ring. (Article 17) The electric machine of any preceding clause, wherein a plurality of stand-alone U-shaped clips are disposed between the first ring and the second ring. (Article 18) 10. The electric machine of claim 9, wherein the yokes of the groups from the plurality of U-shaped clips are interconnected. (Article 19) The electric machine of any preceding clause, wherein a plurality of first teeth and a plurality of second teeth are disposed within each coil opening, and at least one pair of specific first teeth and specific second teeth has a length greater than the lengths of other first teeth and second teeth disposed within each coil opening. (Article 20) 10. The electric machine of any preceding clause, wherein the electric machine includes a stator positioned radially outward of a rotor, and the plurality of U-shaped clips form part of the stator. (Article 21) a plurality of coils, each coil defining a coil opening, each coil opening including a first section, a second section, and an intermediate section between the first section and the second section; At least one first yoke; a plurality of first wedge-shaped teeth integrally formed with and extending from the at least one first yoke, wherein each of the plurality of first wedge-shaped teeth extends within the first section thereof into a different one of the plurality of coil openings; At least one second yoke; a plurality of second wedge-shaped teeth integrally formed with and extending from the at least one second yoke, wherein each of the plurality of second wedge-shaped teeth extends within the second section thereof into a different one of the plurality of coil openings; at least one intermediate yoke between the at least one first yoke and the at least one second yoke; and a plurality of intermediate wedge-shaped teeth integrally formed with and extending from the at least one intermediate yoke, the plurality of intermediate wedge-shaped teeth extending within the intermediate section thereof into different ones of the plurality of coil openings; 1. An electric machine as described in this clause alone or in combination with any of the preceding clauses, comprising: (Article 22) The electric machine of any preceding clause, wherein a pair of intermediate wedge-shaped teeth are disposed within each coil opening. (Article 23) The electric machine of any preceding clause, wherein only one first wedge-shaped tooth and only one second wedge-shaped tooth are disposed within each coil opening. (Article 24) The electric machine of any preceding clause, wherein a single intermediate wedge-shaped tooth is disposed within each coil opening. (Article 25) The electric machine of any preceding clause, wherein the intermediate wedge-shaped teeth have a wedge shape that is different from the wedge shapes of at least some of the first wedge-shaped teeth and the second wedge-shaped teeth. (Article 26) 10. The electric machine of claim 9, wherein the intermediate wedge-shaped tooth is wedge-shaped in a first plane, and the first wedge-shaped tooth and the second wedge-shaped tooth are wedge-shaped in a second plane that is transverse to the first plane. (Article 27) 10. The electric machine of any preceding clause, wherein the first plane is perpendicular to an axis of rotation of the electric machine. (Article 28) 10. The electric machine of any preceding clause, wherein the first wedge-shaped tooth and the second wedge-shaped tooth are also wedge-shaped in the first plane. (Article 29) The electric machine of any preceding clause, wherein the at least one first yoke includes a plurality of first yokes, a pair of first wedge-shaped teeth extending from each of the plurality of first yokes, and the at least one second yoke includes a plurality of second yokes, a pair of second wedge-shaped teeth extending from each of the plurality of second yokes. (Article 30) 10. The electric machine of any preceding clause, wherein the at least one first yoke, the at least one second yoke, and the at least one intermediate yoke are part of a stator of the electric machine. (Article 31) 10. The electric machine of any preceding clause, further comprising a rotor positioned radially inward of the stator. (Article 32) 10. The electric machine of any preceding clause, wherein the first plurality of wedge-shaped teeth and the second plurality of wedge-shaped teeth share a common size and shape. (Article 33) 10. The electric machine of claim 9, wherein the plurality of coils are arranged symmetrically about an axis of rotation of the electric machine, and the coil opening of each coil includes a tooth structure formed from a single first wedge-shaped tooth, a single second wedge-shaped tooth, and a pair of adjacently positioned intermediate wedge-shaped teeth. (Article 34) The electric machine of any preceding clause, wherein the plurality of coils are arranged symmetrically about an axis of rotation of the electric machine, and the coil opening of each coil includes a tooth structure formed from a single first wedge-shaped tooth, a single second wedge-shaped tooth, and a single intermediate wedge-shaped tooth. (Article 35) 10. The electric machine of any preceding clause, wherein the at least one first yoke, the at least one second yoke, and the at least one intermediate yoke are arc-shaped. (Article 36) 10. The electric machine of any preceding clause, wherein the at least one intermediate yoke includes two stacked intermediate yokes. (Article 37) 10. The electric machine of any preceding clause, wherein the first, second, and intermediate wedge-shaped teeth in each coil opening collectively form a multi-component tooth, the multi-component tooth extending in a radial direction of the electric machine and shaped such that multiple cross-sectional areas of the multi-component tooth vary in multiple planes perpendicular to the radial direction, and the perimeters of the multiple cross-sections are substantially the same across the multiple planes. (Article 38) 10. The electric machine of any preceding clause, wherein the cross-sectional area of ​​each multi-component tooth in a plane perpendicular to the radial direction increases towards the axis of rotation of the electric machine. (Article 39) 10. The electric machine of any preceding clause, wherein the cross-sectional shape of each multi-component tooth in at least one of an axial or radial plane of the electric machine is trapezoidal. (Article 40) 10. The electric machine of any preceding clause, wherein the electric machine is a generator or an electric motor. (Article 41) 1. An electric machine comprising: a plurality of electromagnetic coils, each electromagnetic coil defining a trapezoidally shaped, tapered coil opening, the plurality of electromagnetic coils being arranged circumferentially about an axis of rotation of the electric machine; a plurality of yokes each extending in an axial direction, wherein at least one of the plurality of yokes is tapered in the axial direction; and a plurality of teeth, at least one tooth of the plurality of teeth extending from each of the plurality of yokes, each of the plurality of teeth tapering in a radial direction to enable the plurality of teeth to fit within a corresponding trapezoidally shaped, tapered coil opening; 1. An electric machine as described in this clause alone or in combination with any of the preceding clauses, comprising: (Article 42) 10. The electric machine of claim 9, wherein only one of the plurality of teeth extends from each of the plurality of yokes. (Article 43) 10. The electric machine of claim 9, wherein each yoke of the plurality of yokes is tapered along two edges in the axial direction such that one side of the yoke is wider than the other side of the yoke. (Article 44) 10. The electric machine of any preceding clause, wherein the wide side of each yoke is positioned adjacent to the narrower side of an adjacent yoke. (Article 45) 10. The electric machine of any preceding clause, wherein each tooth of the plurality of teeth is tapered in four planes. (Article 46) 10. The electric machine of any preceding clause, wherein each tooth of the plurality of teeth is tapered in two planes, and the electric machine further comprises a pair of shims disposed on opposite sides of each tooth of the plurality of teeth. (Article 47) 10. The electric machine of claim 9, wherein the two tapered planes are transverse to each other. (Article 48) 10. An electric machine as described in any preceding clause, wherein at least three sides of each shim are tapered. (Article 49) 10. The electric machine of any preceding clause, wherein the outer surfaces of the plurality of yokes cooperate to form a cylindrical shape. (Article 50) The electric machine of any preceding clause, wherein an edge of at least one yoke of the plurality of yokes is not aligned with an edge of an adjacent yoke. (Article 51) 10. The electric machine of any preceding clause, further comprising a rotor positioned radially inward of the plurality of electromagnetic coils. (Article 52) 10. The electric machine of any preceding clause, further comprising a rotor positioned radially outward of the plurality of electromagnetic coils. (Article 53) 10. The electric machine of any preceding clause, wherein the plurality of teeth are formed from an SMC material. (Article 54) 10. The electric machine of any preceding clause, wherein the plurality of teeth are formed from laminated steel. (Article 55) The electric machine of any preceding clause, wherein at least one yoke has two of the plurality of teeth extending therefrom. (Article 56) 10. The electric machine of any preceding clause, wherein the teeth in each coil opening combine to form a wedge-shaped multi-component tooth extending in a radial direction of the electric machine and shaped such that cross-sectional areas of the multi-component tooth vary in planes perpendicular to the radial direction, and perimeters of the cross-sections are substantially the same across the planes. (Article 57) 10. The electric machine of any preceding clause, wherein the cross-sectional area of ​​each multi-component tooth in a plane perpendicular to the radial direction increases towards the axis of rotation of the electric machine. (Article 58) 10. The electric machine of any preceding clause, wherein the cross-sectional shape of each multi-component tooth in at least one of an axial or radial plane of the electric machine is trapezoidal. (Article 59) 10. The electric machine of any preceding clause, wherein the electric machine is a generator. (Article 60) 10. The electric machine of any preceding clause, wherein the electric machine is an electric motor. (Article 61) rotor; stator; a heat dissipation plate having a first side disposed in thermal communication with the stator, the heat dissipation plate having a central opening therein and having an outer periphery; and a plurality of circumferentially distributed Y-shaped or ψ-shaped cooling fins extending from a second side of the heat dissipation plate opposite the first side, each cooling fin having a radially extending leg portion and a V-shaped or ψ-shaped deflector portion, each V-shaped or ψ-shaped deflector portion facing the outer periphery of the heat dissipation plate to deflect a first portion of the airflow outward, and each radially extending leg portion positioned to direct a portion of the airflow inward toward the central opening; 1. An air-cooled electric machine as described in this clause alone or in combination with any of the preceding clauses, comprising: (Article 62) 10. The electric machine of any preceding clause, wherein the second side of the heat dissipation plate further includes non-Y-shaped and non-ψ-shaped cooling fins disposed between adjacent Y-shaped or ψ-shaped cooling fins. (Article 63) 10. The electric machine of any preceding clause, wherein the non-Y-shaped and non-ψ-shaped cooling fins are linear cooling fins extending from the periphery of the heat dissipation plate toward the central opening. (Article 64) 10. The electric machine of any preceding clause, wherein the Y-shaped or ψ-shaped cooling fins are arranged symmetrically about the central opening. (Article 65) 10. The electric machine of any preceding clause, wherein the second side of the heat dissipation plate further includes a plurality of cooling pins disposed radially inward of the Y-shaped or ψ-shaped cooling fins. (Article 66) 10. The electric machine of any preceding clause, wherein the plurality of cooling pins are symmetrically disposed about the central opening. (Article 67) 10. The electric machine of any preceding clause, wherein the plurality of cooling pins are positioned at a common radial distance from the central opening. (Article 68) The electric machine of any preceding clause, wherein the plurality of cooling pins includes a first set of cooling pins positioned at a first common radial distance from the central opening and a second set of cooling pins positioned at a different second common radial distance from the central opening. (Article 69) 10. The electric machine of claim 9, wherein the heat dissipation plate further includes a plurality of cavities extending from the second side to the first side, the plurality of cavities being symmetrically positioned about the central opening. (Article 70) 10. The electric machine of any preceding clause, wherein the heat dissipation plate is formed from aluminum. (Article 71) 10. The electric machine of claim 9, wherein the Y-shaped or ψ-shaped cooling fins are arranged such that they radiate outward from the center of the cooling plate. (Article 72) 10. The electric machine of any preceding clause, wherein the electric machine is a generator. (Article 73) 10. The electric machine of any preceding clause, wherein the electric machine is an electric motor.

[0131] The disclosed embodiments of the electric machine may include any one of the following itemized features alone or in combination with one or more of the other itemized features. Electrical machinery Multiple coils Each coil of the plurality of coils defines a coil opening. Multiple U-shaped clips Each U-shaped clip has a first tooth, a second tooth, and a yoke interconnecting the first tooth and the second tooth. The first tooth of each U-shaped clip is disposed within the coil opening of one of the plurality of coils. The second tooth of each U-shaped clip is disposed within another coil opening of an adjacent coil. The yoke bridges two adjacent coils The two side walls of two adjacent coils are sandwiched between the first and second teeth of each U-shaped clip. Each coil aperture includes a plurality of teeth arranged along the length of the aperture. One or more of the teeth fill the entire width of each opening. A single tooth of the multiple teeth fills the entire width of each opening. The plurality of teeth includes at least upper teeth, lower teeth, and central teeth. At least one of the upper or lower teeth fills the entire width of each opening At least one of the upper or lower teeth includes an arc-shaped yoke having a plurality of teeth extending therefrom. Each coil opening has at least one first tooth of a first group of the plurality of U-shaped clips and at least one first tooth of a second group of the plurality of U-shaped clips. · Group 1 is different from Group 2. At least one first tooth of the first group has a length greater than a length of at least one first tooth of the second group. At least two first teeth of the second group have a common length. A group of a plurality of U-shaped clips has a first tooth disposed within a coil opening of one of the plurality of coils. At least one U-shaped clip in the group has a first wedge-shaped tooth. At least one U-shaped clip in the group has a second tooth that is wedge-shaped. At least one U-shaped clip in the group is made from an SMC material. All of the U-shaped clips in the group are made of SMC material. All of the U-shaped clips in the group are made from laminated steel. The length dimension of each wedge-shaped first tooth varies from one end of the coil opening to the opposite end of the coil opening. Multiple yokes work together to form a ring. The plurality of yokes cooperate to form a first ring and a second ring. A plurality of stand-alone U-shaped clips are disposed between the first ring and the second ring. · Group yokes from multiple U-shaped clips are interconnected. A plurality of first teeth and a plurality of second teeth are disposed within each coil opening. The length of at least one pair of specific first teeth and specific second teeth is greater than the lengths of the other first teeth and second teeth disposed within each coil opening. The electric machine comprises a stator positioned radially outward of the rotor A number of U-shaped clips form part of the stator. Each coil opening includes a first section, a second section, and an intermediate section between the first section and the second section; At least one first yoke; a plurality of first wedge-shaped teeth integrally formed with and extending from the at least one first yoke; Each of the plurality of first wedge-shaped teeth extends within a first section thereof into a different one of the plurality of coil openings. At least one second yoke. A plurality of second wedge-shaped teeth integrally formed with and extending from the at least one second yoke. Each of the plurality of second wedge-shaped teeth extends within its second section into a different one of the plurality of coil openings. At least one intermediate yoke between the at least one first yoke and the at least one second yoke. A plurality of intermediate wedge-shaped teeth integrally formed with and extending from the at least one intermediate yoke. The plurality of intermediate wedge-shaped teeth extend within an intermediate section thereof into different ones of the plurality of coil openings. A pair of intermediate wedge-shaped teeth are disposed within each coil opening. Only one first wedge-shaped tooth and only one second wedge-shaped tooth are disposed within each coil opening. A single intermediate wedge-shaped tooth is disposed within each coil opening. The intermediate wedge-shaped teeth have a wedge shape that is different from the wedge shapes of at least some of the first wedge-shaped teeth and the second wedge-shaped teeth. The intermediate wedge-shaped tooth is wedge-shaped in the first plane. The first wedge-shaped tooth and the second wedge-shaped tooth are wedge-shaped in a second plane that is transverse to the first plane. The first plane is perpendicular to the axis of rotation of the electrical machine. The first wedge-shaped tooth and the second wedge-shaped tooth are also wedge-shaped in the first plane. The at least one first yoke includes a plurality of first yokes. A pair of first wedge-shaped teeth extends from each of the plurality of first yokes. The at least one second yoke includes a plurality of second yokes. A pair of second wedge-shaped teeth extends from each of the plurality of second yokes. The at least one first yoke, the at least one second yoke and the at least one intermediate yoke are part of a stator of the electric machine. A rotor positioned radially inside the stator. The first plurality of wedge-shaped teeth and the second plurality of wedge-shaped teeth share a common size and shape. The coils are arranged symmetrically around the axis of rotation of the electric machine. Each coil includes a tooth structure formed from a single first wedge-shaped tooth, a single second wedge-shaped tooth, and a pair of adjacently positioned intermediate wedge-shaped teeth. The coils are arranged symmetrically around the axis of rotation of the electric machine. The coil opening of each coil includes a tooth structure formed from a single first wedge-shaped tooth, a single second wedge-shaped tooth, and a single intermediate wedge-shaped tooth. The at least one first yoke, the at least one second yoke, and the at least one intermediate yoke are arc-shaped. The at least one intermediate yoke includes two stacked intermediate yokes. The first, second, and intermediate wedge-shaped teeth in each coil opening collectively form a multi-component tooth, the multi-component tooth extending in a radial direction of the electric machine. The wedge-shaped multi-component tooth is shaped so that the cross-sectional areas of the multi-component tooth vary in planes perpendicular to the radial direction. The perimeters of the multiple cross sections of the multi-part tooth are substantially the same across multiple planes. The cross-sectional area of ​​each multi-component tooth in a plane perpendicular to the radial direction increases towards the axis of rotation of the electric machine. The cross-sectional shape of each multi-component tooth in at least one of the axial or radial planes of the electric machine is trapezoidal. The electric machine is a generator or an electric motor. A plurality of electromagnetic coils, wherein each electromagnetic coil defines a trapezoidally shaped, tapered coil opening. The electromagnetic coils are arranged in a circumferential direction around the rotation axis of the electric machine. Multiple yokes, each extending axially. At least one of the plurality of yokes is tapered in the axial direction. Multiple teeth. At least one tooth of the plurality of teeth extends from each of the plurality of yokes. Each of the plurality of teeth is radially tapered to allow the plurality of teeth to fit within a corresponding trapezoidally shaped, tapered coil opening. Only one of the plurality of teeth extends from each of the plurality of yokes. Each yoke of the plurality of yokes is tapered along two edges in the axial direction so that one side of the yoke is wider than the other side of the yoke. The wide side of each yoke is positioned adjacent to the narrower side of the adjacent yoke. Each tooth of the plurality of teeth is tapered in four planes. Each tooth of the plurality of teeth is tapered in two planes. A pair of shims disposed on opposite sides of each tooth of the plurality of teeth. The two tapered planes are transverse to each other. At least three sides of each shim are tapered. The outer surfaces of the multiple yokes work together to form a cylindrical shape. The edge of at least one of the yokes is not aligned with the edge of an adjacent yoke. A rotor positioned radially inward of multiple electromagnetic coils. A rotor positioned radially outward of multiple electromagnetic coils. · Multiple teeth are formed from SMC material. Multiple teeth are formed from laminated steel. At least one yoke has two of the plurality of teeth extending therefrom. The teeth in each coil opening combine to form a wedge-shaped multi-part tooth that extends radially of the electric machine. The cross-sectional area of ​​each multi-component tooth in a plane perpendicular to the radial direction increases towards the axis of rotation of the electric machine. The cross-sectional shape of each multi-component tooth in at least one of the axial or radial planes of the electric machine is trapezoidal. Air-coolable electrical machines. Rotor. Stator. A heat dissipation plate having a first side positioned in thermal communication with the stator. The heat dissipation plate has a central opening therein and an outer periphery A plurality of circumferentially distributed Y-shaped or ψ-shaped cooling fins extending from a second side of the heat dissipation plate opposite the first side. Each cooling fin has a radially extending leg portion and a V-shaped or ψ-shaped deflector portion. Each V-shaped or ψ-shaped deflector section deflects a first portion of the airflow outwardly, facing the outer periphery of the heat dissipation plate. Each radially extending leg portion is positioned to direct a portion of the airflow inwardly toward the central opening. The second side of the heat dissipation plate further includes non-Y-shaped and non-ψ-shaped cooling fins disposed between adjacent Y-shaped or ψ-shaped cooling fins. Non-Y-shaped and non-ψ-shaped cooling fins are linear cooling fins that extend from the periphery of the heat dissipation plate toward the central opening. The Y-shaped or ψ-shaped cooling fins are arranged symmetrically around the central opening. The second side of the heat dissipation plate further includes a plurality of cooling pins disposed radially inside the Y-shaped or ψ-shaped cooling fins. The cooling pins are arranged symmetrically around the central opening. The cooling pins are positioned at a common radial distance from the central opening. The plurality of cooling pins includes a first set of cooling pins positioned at a first common radial distance from the central opening and a second set of cooling pins positioned at a different second common radial distance from the central opening. The heat dissipation plate further includes a plurality of cavities extending from the second side to the first side. The cavities are positioned symmetrically around the central opening. The heat dissipation plate is made of aluminum. The Y-shaped or ψ-shaped cooling fins are arranged so that they radiate outward from the center of the cooling plate.

[0132] The systems and methods disclosed herein involve unconventional improvements over conventional approaches. The description of the disclosed embodiments is not exhaustive and is not limited to the precise forms or embodiments disclosed. Modifications and adaptations of the embodiments will be apparent from consideration of the specification and practice of the disclosed embodiments. Additionally, the disclosed embodiments are not limited to the examples discussed herein.

[0133] The foregoing description has been presented for purposes of illustration. It is not exhaustive or limited to the precise form or embodiments disclosed. Modifications and adaptations of the embodiments will be apparent from consideration of the specification and practice of the disclosed embodiments. For example, while the described implementations include both hardware and software, systems and methods according to the present disclosure may be implemented solely in hardware.

[0134] The features and advantages of the present disclosure will be apparent from the detailed specification, and therefore, the appended claims are intended to cover all systems and methods that fall within the true spirit and scope of the present disclosure. As used herein, the indefinite articles "a" and "an" mean "one or more." Similarly, the use of plural terms does not necessarily imply a plurality unless otherwise clear in a given context. Words such as "and" or "or" mean "and / or" unless specifically indicated otherwise. Moreover, because numerous modifications and variations will readily occur upon review of this disclosure, it is not desired to limit the disclosure to the exact construction and operation shown and described, and recourse may therefore be had to all suitable modifications and equivalents that are within the scope of the present disclosure.

[0135] Furthermore, although exemplary embodiments have been described herein, the scope may include any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations, or alterations based on this disclosure. Claim elements should be construed broadly based on the language employed in the claims and not limited to the examples described herein or during prosecution of the application, which examples should be construed as non-exclusive. Furthermore, the steps of the disclosed methods may be modified in any manner, including by changing the order of steps or inserting or deleting steps. Accordingly, it is intended that the specification and examples be considered exemplary only, with the true scope and spirit being indicated by the following claims and the full scope of equivalents thereto.

Claims

1. a plurality of coils, wherein each coil of the plurality of coils defines a coil opening; and a plurality of U-shaped clips, each U-shaped clip having a first tooth, a second tooth, and a yoke interconnecting the first tooth and the second tooth; Equipped with wherein the first tooth of each U-shaped clip is disposed in one coil opening of the plurality of coils, the second tooth of each U-shaped clip is disposed in another coil opening of an adjacent coil, the yoke bridges two adjacent coils, and two side walls of the two adjacent coils are sandwiched between the first tooth and the second tooth of each U-shaped clip. Electrical machinery.

2. The electric machine of claim 1 , wherein each coil opening includes a plurality of teeth arranged along a length of the coil opening extending along an axis of rotation of the electric machine.

3. The electric machine of claim 2 , wherein one or more of the plurality of teeth fills the entire width of each opening.

4. The electric machine of claim 2 , wherein a single tooth of the plurality of teeth fills the entire width of each opening.

5. 3. The electric machine of claim 2, wherein the plurality of teeth includes at least upper teeth, lower teeth, and center teeth, and at least one of the upper teeth or the lower teeth fills the entire width of each opening and includes an arc-shaped yoke from which the plurality of teeth extend.

6. 2. The electric machine of claim 1, wherein each coil opening includes at least one first tooth of a first group of the plurality of U-shaped clips and at least one first tooth of a second group of the plurality of U-shaped clips, the first group being different from the second group.

7. The electric machine of claim 6 , wherein the at least one first tooth of the first group has a length that is greater than a length of the at least one first tooth of the second group.

8. The electric machine of claim 7 , wherein at least two first teeth of the second group have a common length.

9. 2. The electric machine of claim 1, wherein a group of the plurality of U-shaped clips has a first tooth disposed within the coil opening of one of the plurality of coils, and at least one U-shaped clip in the group has a wedge-shaped first tooth.

10. The electric machine of claim 9 , wherein the at least one U-shaped clip in the group has a second tooth that is wedge-shaped.

11. The electric machine of claim 10 , wherein the at least one U-shaped clip in the group is made from an SMC material.

12. The electric machine of claim 10 , wherein all of the U-shaped clips in the group are made from an SMC material.

13. The electric machine of claim 10 , wherein all of the U-shaped clips in the group are made from laminated steel.

14. The electric machine of claim 10 , wherein a length dimension of each wedge-shaped first tooth varies from one end of the coil opening to an opposite end of the coil opening.

15. The electric machine of claim 1 , wherein a plurality of the yokes cooperate to form a ring.

16. The electric machine of claim 1 , wherein a plurality of the yokes cooperate to form a first ring and a second ring.

17. The electric machine of claim 16 , wherein a plurality of stand-alone U-shaped clips are disposed between the first ring and the second ring.

18. 18. An electric machine according to any one of the preceding claims, wherein the yokes of groups from the plurality of U-shaped clips are interconnected.

19. 18. The electric machine of claim 1, wherein a plurality of first teeth and a plurality of second teeth are disposed within each coil opening, and at least one pair of specific first teeth and specific second teeth has a length greater than a length of other first teeth and second teeth disposed within each coil opening.

20. 18. An electric machine according to any preceding claim, wherein the electric machine comprises a stator positioned radially outward of a rotor, the plurality of U-shaped clips forming part of the stator.

21. a plurality of coils, each coil defining a coil opening, each coil opening including a first section, a second section, and an intermediate section between the first section and the second section; at least one first yoke; a plurality of first wedge-shaped teeth integrally formed with and extending from the at least one first yoke, wherein each of the plurality of first wedge-shaped teeth extends within the first section thereof into a different one of the plurality of coil openings; at least one second yoke; a plurality of second wedge-shaped teeth integrally formed with and extending from the at least one second yoke, wherein each of the plurality of second wedge-shaped teeth extends within the second section thereof into a different one of the plurality of coil openings; at least one intermediate yoke between the at least one first yoke and the at least one second yoke; and a plurality of intermediate wedge-shaped teeth integrally formed with and extending from the at least one intermediate yoke, the plurality of intermediate wedge-shaped teeth extending within the intermediate section thereof into different ones of the plurality of coil openings; An electric machine comprising:

22. The electric machine of claim 21 , wherein a pair of intermediate wedge-shaped teeth are disposed within each coil opening.

23. The electric machine of claim 21 , wherein a single intermediate wedge-shaped tooth is disposed within each coil opening.

24. The electric machine of claim 23 , wherein only one first wedge-shaped tooth and only one second wedge-shaped tooth are disposed within each coil opening.

25. The electric machine of claim 21 , wherein the intermediate wedge-shaped tooth has a wedge shape that is different from the wedge shape of at least some of the first wedge-shaped tooth and the second wedge-shaped tooth.

26. 26. The electric machine of claim 25, wherein the first wedge-shaped tooth, the second wedge-shaped tooth, and the intermediate wedge-shaped tooth have trapezoidal cross-sectional shapes in a radial plane, and the first wedge-shaped tooth and the second wedge-shaped tooth have trapezoidal cross-sectional shapes in an axial plane.

27. 22. The electric machine of claim 21, wherein the at least one first yoke comprises a plurality of first yokes with at least one pair of first wedge-shaped teeth extending from each of the plurality of first yokes, and the at least one second yoke comprises a plurality of second yokes with at least one pair of second wedge-shaped teeth extending from each of the plurality of second yokes.

28. The electric machine of claim 21 , wherein the at least one first yoke, the at least one second yoke, and the at least one intermediate yoke are part of a stator of the electric machine.

29. The electric machine of claim 28 further comprising a rotor positioned radially inward of the stator.

30. The electric machine of claim 21 , wherein the first plurality of wedge-shaped teeth and the second plurality of wedge-shaped teeth share a common size and shape.

31. 22. The electric machine of claim 21, wherein the plurality of coils are arranged symmetrically about an axis of rotation of the electric machine, and the coil opening of each coil includes a tooth structure formed from a single first wedge-shaped tooth, a single second wedge-shaped tooth, and a pair of adjacently positioned intermediate wedge-shaped teeth.

32. 22. The electric machine of claim 21, wherein the plurality of coils are arranged symmetrically about an axis of rotation of the electric machine, and the coil opening of each coil includes a tooth structure formed from a single first wedge-shaped tooth, a single second wedge-shaped tooth, and a single intermediate wedge-shaped tooth.

33. The electric machine of claim 21 , wherein the at least one first yoke, the at least one second yoke, and the at least one intermediate yoke are arc-shaped.

34. 34. The electric machine of claim 33, wherein at least one of the first yoke, the second yoke, and the intermediate yoke is fabricated in the form of a ring including at least two circular arc segments.

35. 35. The electric machine of claim 34, wherein the at least one intermediate yoke comprises at least two intermediate yokes stacked along an axis of rotation of the electric machine.

36. 36. The electric machine of claim 21, wherein the first wedge-shaped tooth, the second wedge-shaped tooth, and the intermediate wedge-shaped tooth in each coil opening collectively form a multi-component tooth extending in a radial direction of the electric machine and shaped such that multiple cross-sections of the multi-component tooth in multiple planes perpendicular to the radial direction have varying cross-sectional areas and perimeters of the multiple cross-sections that are substantially the same across the multiple planes.

37. 37. The electric machine of claim 36, wherein the cross-sectional shape of each multi-component tooth in at least one of an axial or radial plane of the electric machine is trapezoidal.

38. 36. An electric machine according to any one of claims 21 to 35, wherein the electric machine is a generator or an electric motor.

39. 1. An electric machine comprising: a plurality of electromagnetic coils, each electromagnetic coil defining a trapezoidally shaped, tapered coil opening, the plurality of electromagnetic coils being circumferentially arranged about an axis of rotation of the electric machine; a plurality of yokes each extending in an axial direction, wherein at least one of the plurality of yokes is tapered in the axial direction; and a plurality of teeth, at least one tooth of said plurality of teeth extending from each of said plurality of yokes, each of said plurality of teeth tapering in a radial direction to enable said plurality of teeth to fit within a corresponding trapezoidally shaped, tapered coil opening; An electric machine comprising:

40. 40. The electric machine of claim 39, wherein only one of the plurality of teeth extends from each of the plurality of yokes.

41. 40. The electric machine of claim 39, wherein each yoke of the plurality of yokes is tapered along two edges in the axial direction such that one side of the yoke is wider than the other side of the yoke.

42. 42. The electric machine of claim 41, wherein the wide side of each yoke is positioned adjacent to the narrower side of an adjacent yoke.

43. 40. The electric machine of claim 39, wherein each tooth of the plurality of teeth is tapered in four planes.

44. 40. The electric machine of claim 39, wherein each tooth of the plurality of teeth is tapered in two planes, the electric machine further comprising a pair of shims disposed on opposite sides of each tooth of the plurality of teeth.

45. 45. The electric machine of claim 44, wherein the two tapered planes are transverse to each other.

46. 45. The electric machine of claim 44, wherein at least three sides of each shim are tapered.

47. 40. The electric machine of claim 39, wherein the outer surfaces of the plurality of yokes cooperate to form the shape of a cylinder.

48. 40. The electric machine of claim 39, wherein an edge of at least one yoke of the plurality of yokes is misaligned with an edge of an adjacent yoke.

49. 40. The electric machine of claim 39, further comprising a rotor positioned radially inward of the plurality of electromagnetic coils.

50. 40. The electric machine of claim 39, further comprising a rotor positioned radially outward of the plurality of electromagnetic coils.

51. 40. The electric machine of claim 39, wherein the plurality of teeth are formed from an SMC material.

52. 40. The electric machine of claim 39, wherein the plurality of teeth are formed from laminated steel.

53. 40. The electric machine of claim 39, wherein at least one yoke has two of the plurality of teeth extending therefrom.

54. 40. The electric machine of claim 39, wherein the teeth in each coil opening combine to form a wedge-shaped multi-component tooth extending in a radial direction of the electric machine and shaped such that a plurality of cross sections of the wedge-shaped multi-component tooth have varying cross-sectional areas in a plurality of planes perpendicular to the radial direction and a perimeter of the cross sections is substantially the same across the planes.

55. 55. The electric machine of claim 54, wherein the cross-sectional area of ​​each multi-piece tooth in a plane perpendicular to the radial direction increases towards an axis of rotation of the electric machine.

56. 55. The electric machine of claim 54, wherein the cross-sectional shape of each multi-component tooth in at least one of an axial or radial plane of the electric machine is trapezoidal.

57. 57. An electric machine according to any one of claims 39 to 56, wherein the electric machine is a generator.

58. 57. An electric machine according to any one of claims 39 to 56, wherein the electric machine is an electric motor.

59. rotor; stator; a heat dissipation plate having a first side disposed in thermal communication with the stator, the heat dissipation plate having a central opening therein and having an outer periphery; and a plurality of circumferentially distributed Y-shaped or ψ-shaped cooling fins extending from a second side of the heat dissipation plate opposite the first side, each cooling fin having a radially extending leg portion and a V-shaped or ψ-shaped deflector portion, each V-shaped or ψ-shaped deflector portion facing the outer periphery of the heat dissipation plate to deflect a first portion of the airflow outward, and each radially extending leg portion positioned to direct a portion of the airflow inward toward the central opening; 1. An air-coolable electric machine comprising:

60. 60. The electric machine of claim 59, wherein the second side of the heat dissipation plate further includes non-Y-shaped and non-ψ-shaped cooling fins disposed between adjacent Y-shaped or ψ-shaped cooling fins.

61. 61. The electric machine of claim 60, wherein the non-Y-shaped and non-ψ-shaped cooling fins are linear cooling fins extending from the periphery of the heat dissipation plate toward the central opening.

62. 60. The electric machine of claim 59, wherein the Y-shaped or ψ-shaped cooling fins are symmetrically positioned about the central opening.

63. 60. The electric machine of claim 59, wherein the second side of the heat dissipation plate further includes a plurality of cooling pins disposed radially inward of the Y-shaped or ψ-shaped cooling fins.

64. 64. The electric machine of claim 63, wherein the plurality of cooling pins are symmetrically positioned about the central opening.

65. 64. The electric machine of claim 63, wherein the plurality of cooling pins are positioned at a common radial distance from the central opening.

66. 64. The electric machine of claim 63, wherein the plurality of cooling pins includes a first set of cooling pins positioned a first common radial distance from the central opening and a second set of cooling pins positioned a second common radial distance different from the central opening.

67. 67. The electric machine of claim 59, wherein the heat dissipation plate further comprises a plurality of cavities extending from the second side to the first side, the plurality of cavities being symmetrically positioned about the central opening.

68. 67. An electric machine as claimed in any one of claims 59 to 66, wherein the heat dissipation plate is formed from aluminium.

69. 67. An electric machine according to any one of claims 59 to 66, wherein the Y-shaped or ψ-shaped cooling fins are arranged such that they radiate outwards from the centre of the cooling plate.

70. 67. An electric machine according to any one of claims 59 to 66, wherein the electric machine is a generator.

71. 67. An electric machine according to any one of claims 59 to 66, wherein the electric machine is an electric motor.

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