Motor

Abstract

A stator for an electric machine defines a central axis and has a first stator face facing parallel to the central axis and a second stator face facing parallel to the central axis, wherein the first and second stator faces face in opposite directions. The stator includes a plurality of ferromagnetic segments arranged about a central axis, each segment having a pair of parallel faces facing parallel to the central axis of the stator. On each stator face, faces of adjacent ones of the plurality of segments form gaps therebetween, the gaps extending radially with respect to the central axis, the gaps on the first stator face being angularly offset from the gaps on the second stator face with respect to the central axis.

Description

Technical Field

[0001] The present disclosure belongs to the field of electric machines. Background Art

[0002] Several configurations of electric motors are available for various applications. One configuration of electric motor is an axial flux permanent magnet motor. This motor can provide high power density and a relatively small thickness, which provides packaging advantages in some applications.

[0003] However, axial flux permanent magnet motors can provide improved performance. Summary of the invention

[0004] A stator for an electric machine defines a central axis and has a first stator face facing parallel to the central axis and a second stator face facing parallel to the central axis, wherein the first stator face and the second stator face face in opposite directions. The stator includes a plurality of ferromagnetic segments arranged around the central axis, each segment having a pair of parallel faces facing parallel to the central axis of the stator. On each stator face, faces of adjacent segments of the plurality of segments form gaps therebetween, the gaps extending radially relative to the central axis, the gaps on the first stator face being angularly offset relative to the central axis from the gaps on the second stator face. The stator also includes conductive windings arranged around the segments and located in slots between the segments, the windings defining an axis parallel to the central axis of the stator.

[0005] As a variant, each segment of the stator may form a "T" shape when viewed radially inwards towards the central axis of the stator. As an additional variant, each segment of the stator may be identical or substantially identical in geometry.

[0006] For each segment of the stator, one of the pairs of faces may be larger than another of the pairs of faces. In addition, a first segment of the plurality of segments may have a second segment and a third segment of the plurality of segments adjacent thereto, wherein the larger face of the first segment faces in a direction opposite to the larger faces of the second segment and the third segment.

[0007] In a further variant, one face of each segment of the stator may at least partially overhang at least one slot. Furthermore, the segments of the stator may each consist of two parts fastened together. Furthermore, the segments of the stator may comprise laminations.

[0008] An electric machine includes a stator defining a central axis and having a first stator face facing parallel to the central axis and a second stator face facing parallel to the central axis, wherein the first stator face and the second stator face face in opposite directions. The stator includes a plurality of ferromagnetic segments arranged about the central axis, each segment having a pair of parallel faces facing parallel to the central axis of the stator. On each stator face, faces of adjacent segments of the plurality of segments form gaps therebetween, the gaps extending radially relative to the central axis, the gaps on the first stator face being angularly offset relative to the central axis from the gaps on the second stator face. The stator also includes an electrically conductive winding arranged about the segments and located in slots between the segments, the winding defining an axis parallel to the central axis of the stator. The electric machine also includes: a first rotor disposed coaxially with the central axis for rotation relative to the stator and axially spaced from the stator by a first air gap; and a second rotor disposed coaxially with the central axis for rotation relative to the stator and axially spaced from the stator by a second air gap. A motor vehicle may include the electric machine.

[0009] An alternative stator for an electric machine defines a central axis. The stator includes a plurality of segments arranged about the central axis of the stator, each segment having a pair of parallel faces parallel to the central axis of the stator and facing in opposite directions. For each segment, one of the faces has a different shape than the other of the faces. The stator also includes conductive windings arranged about the segments and arranged in slots between the segments, the windings defining an axis parallel to the central axis of the stator.

[0010] In alternative stator variations, each segment may form a "T" shape when viewed radially inwardly toward a central axis of the stator. Additionally, the segments of the stator may be identical or substantially identical in geometry. Still further, one face of each segment may at least partially overhang at least one slot, or exactly one face of each segment may at least partially overhang at least one slot. As an improvement, the segments may comprise metal laminations.

[0011] As an additional improvement to the alternative stator, the surface area of ​​one of the pair of faces of each segment may be greater than the surface area of ​​the other of the pair of faces. In addition, a first segment of the plurality of segments may have a second segment and a third segment of the plurality of segments adjacent thereto, and the larger face of the first segment may be in the opposite direction to the larger faces of the second segment and the third segment.

[0012] The present invention provides the following technical solutions:

[0013] 1. A stator for an electric machine, the stator defining a central axis and having a first stator face facing parallel to the central axis and a second stator face facing parallel to the central axis, the first stator face and the second stator face facing in opposite directions, the stator comprising:

[0014] a plurality of ferromagnetic segments arranged about a central axis, each segment having a pair of parallel faces facing parallel to the central axis of the stator, wherein on each stator face, faces of adjacent segments of the plurality of segments form a gap therebetween, the gap extending radially relative to the central axis, the gap on a first stator face being angularly offset relative to the central axis from the gap on a second stator face; and

[0015] An electrically conductive winding is disposed about the segments and in the slots between the segments, the winding defining an axis parallel to a central axis of the stator.

[0016] 2. The stator according to claim 1, wherein each segment forms a "T" shape when viewed radially inward toward a central axis of the stator.

[0017] 3. A stator according to claim 1, wherein the geometric shape of each segment is the same or substantially the same.

[0018] 4. The stator according to claim 1, wherein for each segment, one of the pair of faces is larger than the other of the pair of faces.

[0019] 5. The stator according to claim 4, wherein:

[0020] A first segment of the plurality of segments has a second segment and a third segment of the plurality of segments adjacent thereto; and

[0021] The larger face of the first segment faces in a direction opposite to the larger faces of the second and third segments.

[0022] 6. The stator of claim 1 , wherein a face of each segment at least partially overhangs at least one slot.

[0023] 7. The stator according to claim 1, wherein each segment is composed of two parts fastened together.

[0024] 8. The stator of claim 1 , wherein the segments comprise laminations.

[0025] 9. A motor, comprising:

[0026] A stator for an electric machine, the stator defining a central axis and having a first stator face facing parallel to the central axis and a second stator face facing parallel to the central axis, the first stator face and the second stator face facing in opposite directions, the stator comprising:

[0027] a plurality of ferromagnetic segments arranged about a central axis, each segment having a pair of parallel faces facing parallel to the central axis of the stator, wherein on each stator face, faces of adjacent segments of the plurality of segments form a gap therebetween, the gap extending radially relative to the central axis, the gap on a first stator face being angularly offset relative to the central axis from the gap on a second stator face; and

[0028] an electrically conductive winding disposed about the segments and located in slots between the segments, the winding defining an axis parallel to a central axis of the stator;

[0029] a first rotor disposed coaxially with the central axis for rotation relative to the stator and axially spaced apart from the stator by a first air gap; and

[0030] The second rotor is coaxially arranged with the central axis for rotating relative to the stator and is axially spaced apart from the stator by a second air gap.

[0031] 10. The motor according to claim 9, wherein:

[0032] The first rotor includes a first plurality of permanent magnets disposed opposite the windings of the stator; and

[0033] The second rotor includes a second plurality of permanent magnets disposed opposite the windings of the stator.

[0034] 11. The electric machine according to claim 10, wherein the first rotor and the second rotor are coupled to a common shaft to rotate therewith.

[0035] 12. A motor vehicle comprising the motor according to claim 9.

[0036] 13. A stator for an electric machine, the stator defining a central axis, the stator comprising:

[0037] a plurality of segments disposed about a central axis of the stator, each segment having a pair of parallel faces parallel to the central axis of the stator and facing in opposite directions, wherein for each segment, one of the pair of faces has a different shape than the other of the pair of faces; and

[0038] An electrically conductive winding is disposed about the segments and in the slots between the segments, the winding defining an axis parallel to a central axis of the stator.

[0039] 14. The stator of claim 13, wherein each segment forms a "T" shape when viewed radially inwardly toward a central axis of the stator.

[0040] 15. A stator according to claim 13, wherein the geometric shape of each segment is the same or substantially the same.

[0041] 16. The stator according to claim 13, wherein for each segment, a surface area of ​​one of the pair of faces is greater than a surface area of ​​the other of the pair of faces.

[0042] 17. The stator according to claim 16, wherein:

[0043] A first segment of the plurality of segments has a second segment and a third segment of the plurality of segments adjacent thereto; and

[0044] The larger face of the first segment faces in a direction opposite to the larger faces of the second and third segments.

[0045] 18. The stator of claim 13, wherein a face of each segment at least partially overhangs at least one slot.

[0046] 19. The stator of claim 13, wherein exactly one face of each segment at least partially overhangs at least one slot.

[0047] 20. The stator of claim 13, wherein the segments comprise metal laminations.

[0048] The above summary does not represent every embodiment or every aspect of the present disclosure. When combined with the accompanying drawings and the appended claims, other possible features and advantages will become apparent from the following detailed description of the embodiments for carrying out the present disclosure. In addition, the combinations and sub-combinations of the elements described in the present disclosure are explicitly included in the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a schematic diagram showing an axial flux permanent magnet electric machine and its associated electrical and electronic components.

[0050] Figure 2 yes Figure 1 Exploded view of the magnetic parts of the stator and rotor of a permanent magnet motor.

[0051] Figure 3 A segment comprised in a stator of a permanent magnet electric machine is shown.

[0052] Figure 4 It is an enlarged view of a segment of the stator of a permanent magnet motor.

[0053] Figure 5 A segment of an electrical winding of a stator of a permanent magnet electric machine is shown.

[0054] Figure 6 The cogging torque of a representative axial flux permanent magnet motor and the Figure 1-5 Cogging torque of an exemplary permanent magnet motor.

[0055] Figure 7 The torque ripple of a representative axial flux permanent magnet motor and the Figure 1-5 Torque ripple of an exemplary permanent magnet motor.

[0056] Figure 8 An alternative design of an alternative stator segment of a stator of a permanent magnet electrical machine is shown.

[0057] Fig. 9 Shows Figure 8 The alternative stator segments are arranged around the central axis of the permanent magnet motor. DETAILED DESCRIPTION

[0058] The present disclosure may take many different forms of embodiments. Representative examples of the present disclosure are shown in the accompanying drawings and described in detail herein as non-limiting examples of the disclosed principles. For this reason, elements and limitations described in the abstract, background technology, summary of the invention, and detailed description, but not explicitly stated in the claims, should not be incorporated into the claims individually or collectively by implication, inference, or otherwise.

[0059] For the purposes of this description, unless expressly disclaimed, the use of the singular includes the plural and vice versa, the terms "and" and "or" shall be both conjunctive and disjunctive, "any" and "all" shall mean "any and all", and the words "including", "containing", "comprising", "having", etc. shall mean "including but not limited to". In addition, approximate words such as "approximately", "nearly", "substantially", "roughly", "about", etc. may be used herein in the sense of "within, close to, or nearly within..." or "within 0-5% of...", or "within an acceptable manufacturing tolerance range", or any logical combination thereof.

[0060] First reference Figure 1 , an electric machine 10 is shown. The electric machine 10 may be an axial flux permanent magnet electric machine, such as an electric motor. The electric machine 10 may have a non-rotating stator 12 fixed to a housing (not shown). The stator 12 defines a central axis 14, which serves as the axis of rotation of two permanent magnet rotors, a rotor 16 and a rotor 18. The rotors 16 and 18 may be fixed to a common shaft 20 for rotation therewith, wherein the shaft 20 is supported by bearings within the housing of the electric machine 10 and is appropriately journaled for rotation within the stator 12. The rotor 16 is separated from the stator 12 by an air gap 17, and the rotor 18 is separated from the stator 12 by an air gap 19. The electric machine 10 may be of a so-called yokeless variety; that is, the stator 12 may not include a back iron through which magnetic flux flows in the stator 12.

[0061] The stator 12 is wound with an electrical winding 21 that provides magnetic flux for interacting with the permanent magnets of the rotor 16 and the rotor 18 to generate mechanical rotational force from the motor 10 when the motor 10 is used as a motor. The windings may be powered by a power inverter module (PIM) 23 that converts stored electrical energy from a traction battery (B+) 22 into alternating current (AC) electrical energy. An electronic control unit (ECU) 24 may be integrated with the power inverter module 23 or may be a separate controller that controls the operation of the power inverter module 23. The ECU 24 is an electronic controller with sufficient electronic resources (microcontroller, memory, software, input, output, etc.) to control the motor 10. If the rotor 16 and the rotor 18 are rotated by the input of mechanical energy, the motor 10 may alternatively operate as a generator.

[0062] like Figure 1 The electric machine 10 configured in the embodiment of the present invention can be characterized as an "axial flux" machine because the magnetic flux generated by the windings 21 travels axially, i.e., parallel to the central axis 14 of the electric machine 10. This can be contrasted with a so-called "radial flux" machine in which the stator can be arranged around the rotor and the magnetic flux travels radially relative to the central axis of the electric machine. The electric machine 10 can be used to power a motor vehicle 13 (e.g., an electric vehicle or a hybrid electric vehicle).

[0063] Additional references Figure 2 , the rotor 16 may have a plurality of permanent magnets 26 disposed on the face of the rotor 16 facing the stator 12. The permanent magnets 26 may be secured to a back iron 28 of the rotor 16 by a suitable mechanical method, such as an adhesive. The rotor 18 may have a plurality of permanent magnets 30 disposed on the face of the rotor 18 facing the stator 12. The permanent magnets 30 may be secured to a back iron 32 of the rotor 18 by a suitable mechanical method, such as an adhesive. Considering that the rotor 16 and the rotor 18 may include permanent magnet poles, the motor 10 may be characterized as a "permanent magnet" motor. The stator 12 may have a first stator face 34 and a second stator face 36. The stator face 34 and the stator face 36 may be parallel or substantially parallel to each other. In addition, the stator face 34 and the stator face 36 may each be parallel to the central axis 14 and face in opposite directions from each other, i.e. Figure 1 The right and left sides of the .

[0064] Winding 21( Figure 2 The windings of the stator 12 are shown in the figure only in part (only a portion of which is shown in the figure) can be wound on a segment (such as segment 40a) of the stator 12. Adjacent segments of the stator 12 can form slots, such as slots 38 and 39, in which the windings of the stator 12 are arranged.

[0065] Additional references Figure 3, the stator 12 may be composed of a plurality of segments 40a, 40b, 40c, 40d, 40e, 40f, 40g, 40h, 40i, 40j, 40k, and 40l, but the present disclosure is not limited to stators having 12 segments. Segment 40a may have a first face 44 and a second face 46. Faces 44 and 46 may be mutually or substantially mutually parallel, and when segment 40a is incorporated as part of stator 12, faces 44 and 46 may each face parallel to the central axis 14 of stator 12, although faces 44 and 46 may face in opposite directions. Faces 44 and 46 may have different shapes, and face 46 may have a larger surface area than face 44. When viewed toward the central axis of stator 12 (i.e., for example, from direction 48), segment 40a may have a "T" shape. The stator segments 40 a - 40 l are suitably attached relative to each other, such as by compression rings surrounding the stator segments 40 a - 40 l , or by an adhesive between the stator segments 40 a - 40 l and the housing of the electric machine 10 .

[0066] When the stator segments 40a-40l are incorporated as part of the stator 12, the faces of the stator segments 40a-40l form gaps therebetween, such as gap 60 in the stator face 34 and gap 62 in the stator face 36. The gaps 60 and 62 may be arranged radially or substantially radially relative to the central axis 14. It may be noted that the gaps 60 and 62 may be angularly offset from each other in terms of angular position about the central axis 14.

[0067] Additional references Figure 4 , showing stator segment 40a in more detail. Stator segment 40a can be made of ferromagnetic material. Stator segment 40a can also include laminations 49 of ferromagnetic material (e.g., iron or steel). Alternatively, stator segment 40a can be made of other ferromagnetic materials or other forms of ferromagnetic materials, such as soft magnetic compounds (SMC), molded composite materials of ferromagnetic materials in polymers or other conductive carriers. Stator segments 40b to stator segments 40l can have similar or identical constructions and materials as stator segment 40a.

[0068] The faces 44 and 46 of the stator segment 40a can be flat or substantially flat, and further, when the stator segment 40a is incorporated into the stator 12, the faces 44 and 46 can be parallel to each other and face outward from the stator 12. The faces 44 and 46 can face in opposite directions and can face parallel or substantially parallel to the central axis 14 of the stator 12. It can be noted that the face 44 of the stator segment 40a can be different in shape or size from the face 46 of the stator segment 40a. The surface area of ​​the face 46 can be greater than the surface area of ​​the face 44.

[0069] The other stator segments 40b-40l may have the same geometry, material, and construction as the stator segment 40a. ("Geometry" herein refers to the size and shape of the stator segments 40a-40l.) That is, the other stator segments 40b-40l may be the same as the stator segment 40a. However, as Figure 3 As shown, the stator segments 40a-401 may be installed in the stator 12 in an alternating manner, with the larger surface of one stator segment facing in a direction opposite to the larger surfaces of the two stator segments adjacent thereto.

[0070] Additional references Figure 5 , winding 21 may be composed of segments such as segment 21a, which have a shape that allows segment 21a to slide over the smaller end of segment 40a. Segment 21a may be composed of copper, aluminum, alloys thereof, or other suitable conductive materials to effectively function as a motor winding. Segment 21a may be stamped and then formed into Figure 5 The shape shown facilitates installation on the smaller face 44 of stator segment 40a. Once similarly installed on each stator segment 40a-40l, segment 21a can be appropriately electrically connected, such as in a WYE or DELTA configuration, to form winding 21 of stator 12.

[0071] Segment 40a may be constructed of a ferromagnetic material, such as steel suitable for incorporation into the core of an electric machine. Segment 40a may be formed from laminations. Segments 40b-401 may be constructed similarly to segment 40a.

[0072] The motor 10 may be an 8-pole, 12-slot motor and may be operated with the windings 21 configured as three phases, but these parameters are exemplary only and not limiting.

[0073] The electric machine 10 has been shown to provide certain advantageous performance characteristics. For example, Figure 6 , graph (a) shows the cogging torque of a representative axial flux permanent magnet motor. In contrast, graph (b) shows the significantly smaller cogging torque of the axial flux permanent magnet motor according to the present disclosure.

[0074] Further, then, refer to Figure 7 , graph (a) shows the torque ripple of a representative axial flux permanent magnet motor. On the other hand, graph (b) shows the significantly reduced torque ripple of the axial flux permanent magnet motor according to the present disclosure.

[0075] Figure 6 and Figure 7The improved performance characteristics of the illustrated electric machine 10 may be due to the difference in geometry of faces 44 and 46 of stator segment 40a (as well as the corresponding geometric differences between the corresponding faces of stator segments 40b-40l). The improved performance characteristics may also be due to gaps in stator face 36 (e.g., gap 62) being angularly offset relative to central rotational axis 14 from gaps in stator face 34 (e.g., gap 60). In each case, the magnetic flux generated by stator 12 is more dispersed than in alternative electric machines, thereby smoothing the output torque of electric machine 10. Due to the relative offset of the gaps in stator face 34 and stator face 36 of stator 12, a reduction in cogging torque of electric machine 10 may be achieved. Torque pulsation reduction may be achieved by modulation and phase shifting of the excitation of stator 12 between the two air gaps (air gap 17 and air gap 19).

[0076] Reference now Figure 8 , showing an alternative configuration of a segment of stator 12'. Here, segment 140a may include a first portion 142 and a second portion 144. The first portion 142 and the second portion 144 may be connected at a connecting line 146 to form segment 140a. The first portion 142 and the second portion 144 may be made of a ferromagnetic material, such as laminated iron or steel or a molded ferromagnetic compound such as SMC. The first portion 142 and the second portion 144 may be connected to a winding segment (e.g., winding segment 21a ( Figure 5 The first portion 142 and the second portion 144 may be secured together using an adhesive or another suitable connection method. The segment 140a may have a first face 147 and a second face 149.

[0077] Additional references Fig. 9 , the stator 12' may include segment 140a and additional segments (segments 140b-140l) that may have similar structures, materials, and geometries as segment 140a and are disposed about the central axis of the stator 12'. Faces of adjacent stator segments may have radially extending gaps therebetween (e.g., gaps 150 and 152 in opposing faces of the stator 12'). Gaps such as gap 150 and gap 152 may be offset from one another in terms of their angular position relative to the central axis of the stator 12'.

[0078] The detailed description and the accompanying drawings or figures are support and description of the present teaching, but the scope of the present teaching is limited only by the claims. Although some best modes and other embodiments for carrying out the present teaching have been described in detail, there are various alternative designs and embodiments for practicing the present teaching defined in the appended claims. For example, although the examples provided herein disclose the teachings of the present invention in a motor vehicle environment, these teachings are not limited thereto. In addition, the present disclosure explicitly includes combinations and sub-combinations of the elements and features presented above and below.

Claims

1. A stator for an electric machine, the stator defining a central axis and having a first stator face facing parallel to the central axis and a second stator face facing parallel to the central axis, the first stator face and the second stator face facing in opposite directions, the stator comprising: a plurality of ferromagnetic segments arranged about a central axis, each segment having a pair of parallel faces facing parallel to the central axis of the stator, wherein on each stator face, faces of adjacent segments of the plurality of segments form a gap therebetween, the gap extending radially relative to the central axis, the gap on a first stator face being angularly offset relative to the central axis from the gap on a second stator face; and An electrically conductive winding is disposed about the segments and in the slots between the segments, the winding defining an axis parallel to a central axis of the stator.

2. The stator according to claim 1, wherein: Each segment forms a "T" shape when viewed radially inwardly towards the central axis of the stator.

3. The stator of claim 1, wherein the geometric shape of each segment is the same or substantially the same. 4 . The stator of claim 1 , wherein for each segment, one of the pair of faces is larger than the other of the pair of faces.

5. The stator according to claim 4, wherein: A first segment of the plurality of segments has a second segment and a third segment of the plurality of segments adjacent thereto; as well as The larger face of the first segment faces in a direction opposite to the larger faces of the second and third segments.

6. The stator of claim 1, wherein a face of each segment at least partially overhangs at least one slot.

7. The stator according to claim 1, wherein: Each segment consists of two parts fastened together.

8. The stator of claim 1, wherein the segments comprise laminations.

9. A motor, comprising: The stator according to claim 1; a first rotor disposed coaxially with the central axis for rotation relative to the stator and axially spaced apart from the stator by a first air gap; and The second rotor is coaxially arranged with the central axis for rotating relative to the stator and is axially spaced apart from the stator by a second air gap.

10. A motor vehicle comprising an electric machine according to claim 9.

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