Rotor for electric machine

Abstract

A rotor for an electric machine includes a rotor core having a plurality of circumferentially spaced rotor poles. Each rotor pole may include a plurality of rotor slots arranged into one or more magnetic layers and one or more non-magnetic layers. The magnetic layer may include magnets within one or more of its rotor slots, and the non-magnetic layer does not include magnets within its rotor slots.

Description

Technical Field

[0001] The present disclosure relates to rotors utilized in electric machines, such as, but not necessarily limited to, rotors operable with permanent magnet assisted synchronous reluctance machines. Background Art

[0002] Rare earth (RE), heavy rare earth (HRE), and / or other types of permanent magnets capable of providing a persistent magnetic field may be incorporated into the rotor to maximize performance. As more and more vehicles may employ electric machines, or more specifically electric motors, the materials employed in manufacturing or otherwise utilizing such permanent magnets may become limited. Summary of the invention

[0003] One non-limiting aspect of the present disclosure relates to a rotor for an electric machine having an advantageous structure whereby performance benefits associated with the use of permanent magnets may be employed in a manner that minimizes materials, resources, etc. consumed in manufacturing or otherwise utilizing the permanent magnets.

[0004] One non-limiting aspect of the present disclosure relates to a rotor for an electric machine. The rotor may include a rotor core having a plurality of circumferentially spaced rotor poles, wherein each rotor pole includes a plurality of rotor slots arranged into one or more magnetic layers and one or more non-magnetic layers. The magnetic layer may include magnets within one or more of its rotor slots, and the non-magnetic layer does not include magnets within its rotor slots.

[0005] A centerline of each of the magnetic layers and a centerline of each of the non-magnetic layers may be radially aligned with a centerline of a rotor pole corresponding thereto.

[0006] The apex of each of the magnetic layers may be radially inward of the apex of each of the non-magnetic layers.The apex of the magnetic and non-magnetic layers may be centered relative to a centerline of the rotor pole corresponding thereto.

[0007] The rotor slot of the non-magnetic layer may include a central rotor slot, a first outer rotor slot, and a second outer rotor slot. A first central end of the central rotor slot may be separated from the first outer rotor slot by a first side web, and a second central end of the central rotor slot may be separated from the second outer rotor slot by a second side web. The first side web and the second side web may be part of the rotor core.

[0008] A first peripheral end of the first outer rotor slot may be separated from an outer periphery of the rotor core by a first outer bridge, and a first inner end of the first outer rotor slot may be separated from the central rotor slot by a first side web.

[0009] The second peripheral end of the second outer rotor slot can be separated from the outer periphery by a second outer bridge, and the second inner end of the second outer rotor slot is separated from the central rotor slot by a second side web.

[0010] Each of the rotor poles may include a first nonmagnetic layer and a second nonmagnetic layer among the nonmagnetic layers, and a top end of each of the first nonmagnetic layers is outside a top end of each of the second nonmagnetic layers.

[0011] The first outer rotor slot, the second outer rotor slot, and the center rotor slot of the first non-magnetic layer may have a first parabolic thickness defined relative to a vertex, and the first outer rotor slot, the second outer rotor slot, and the center rotor slot of the second non-magnetic layer may have a second parabolic thickness defined relative to the vertex.

[0012] The first parabolic thickness and the second parabolic thickness may be substantially equal.

[0013] The first side web of the first nonmagnetic layer may have a thickness thinner than that of the second nonmagnetic layer, and the second side web of the first nonmagnetic layer may have a thickness thinner than that of the second side web of the second nonmagnetic layer.

[0014] The thickness of the first outer bridge of the first nonmagnetic layer may be thinner than the thickness of the first outer bridge of the second nonmagnetic layer, and the thickness of the second outer bridge of the first nonmagnetic layer may be thinner than the thickness of the second outer bridge of the second nonmagnetic layer.

[0015] The rotor slots of the magnetic layer may include a middle rotor slot, a first intermediate rotor slot, a second intermediate rotor slot, a first outer rotor slot, and a second outer rotor slot. A first middle end of the middle rotor slot may be separated from the first intermediate rotor slot by a first intermediate web, and a second middle end of the middle rotor slot may be separated from the second intermediate rotor slot by a second intermediate web.

[0016] The first intermediate end of the first intermediate rotor slot can be separated from the first inner end of the first outer rotor slot by the first outer web, and the first middle end of the first intermediate rotor slot can be separated from the middle rotor slot by the first middle web. The second intermediate end of the second intermediate rotor slot can be separated from the second inner end of the second outer rotor slot by the second outer web, and the second middle end of the second intermediate rotor slot can be separated from the middle rotor slot by the second middle web.

[0017] A first outer end of the first outer rotor slot may be separated from the outer periphery by a first outer bridge, and a second outer end of the second rotor slot may be separated from the outer periphery by a second outer bridge.

[0018] Each of the rotor poles may include a third magnetic layer, a fourth magnetic layer, and a fifth magnetic layer in the magnetic layers, and a top end of each of the third magnetic layers may be outside a top end of each of the fourth magnetic layers, and a top end of each of the fourth magnetic layers may be outside a top end of each of the fifth magnetic layers.

[0019] A magnet may be included in each of the middle rotor slots, and no magnet may be included in any of the first outer rotor slot, the second outer rotor slot, the first middle rotor slot, and the second middle rotor slot.

[0020] The first outer rotor slot, the second outer rotor slot, the first middle rotor slot, and the second middle rotor slot of the third magnetic layer may have a third parabolic thickness defined relative to the vertex. The first outer rotor slot, the second outer rotor slot, the first middle rotor slot, and the second middle rotor slot of the fourth magnetic layer may have a fourth parabolic thickness defined relative to the vertex. The first outer rotor slot, the second outer rotor slot, the first middle rotor slot, and the second middle rotor slot of the fifth magnetic layer may have a fifth parabolic thickness defined relative to the vertex.

[0021] The middle rotor slot of the third magnetic layer has a third rectangular shape, the middle rotor slot of the fourth magnetic layer may have a fourth rectangular shape, and the middle rotor slot of the fifth magnetic layer may have a fifth rectangular shape.

[0022] The thickness of each of the third rectangular shape, the fourth rectangular shape, and the fifth rectangular shape may be approximately equal, and optionally, the width of each of the third rectangular shapes may be narrower than the width of each of the fourth rectangular shapes, and the width of each of the fourth rectangular shapes may be narrower than the width of each of the fifth rectangular shapes.

[0023] One non-limiting aspect of the present disclosure relates to a rotor for an electric machine. The rotor may include a rotor core having a plurality of circumferentially spaced rotor poles, wherein each rotor pole includes a plurality of rotor slots arranged into a plurality of layers. The plurality of layers may include: a first non-magnetic layer, the first non-magnetic layer forming its rotor slots to include a central rotor slot, a first outer rotor slot, and a second outer rotor slot; a second non-magnetic layer, the second non-magnetic layer forming its rotor slots to include a central rotor slot, a first outer rotor slot, and a second outer rotor slot; a third magnetic layer, the third magnetic layer forming its rotor slots to include a middle rotor slot, a first intermediate rotor slot, a second intermediate rotor slot, a first outer rotor slot, and a second outer rotor slot; a fourth magnetic layer, the fourth magnetic layer forming its rotor slots to include a middle rotor slot, a first intermediate rotor slot, a second intermediate rotor slot, a first outer rotor slot, and a second outer rotor slot; and a fifth magnetic layer, the fifth magnetic layer forming its rotor slots to include a middle rotor slot, a first intermediate rotor slot, a second intermediate rotor slot, a first outer rotor slot, and a second outer rotor slot. The first non-magnetic layer and the second non-magnetic layer may not include a magnet, and the third magnetic layer, the fourth magnetic layer, and the fifth magnetic layer may include a magnet in each of the middle rotor slots.

[0024] One non-limiting aspect of the present disclosure relates to a vehicle. The vehicle may include an electric motor configured to convert electricity into mechanical power for the purpose of propelling the vehicle. The electric motor may include: a stator including a plurality of stator windings configured to generate a rotating magnetic field (RMF); and a rotor configured to rotate within the stator according to a torque induced by the RMF. The rotor may include a rotor core having a plurality of circumferentially spaced rotor poles, wherein each rotor pole includes a plurality of rotor slots arranged into one or more magnetic layers and one or more non-magnetic layers. The magnetic layer may include a magnet in one or more of its rotor slots, and the non-magnetic layer does not include a magnet in its rotor slot.

[0025] The present invention also discloses the following technical solution:

[0026] Solution 1. A rotor for an electric motor, the rotor comprising:

[0027] A rotor core having a plurality of circumferentially spaced rotor poles, wherein each rotor pole comprises a plurality of rotor slots arranged into one or more magnetic layers and one or more non-magnetic layers, wherein the magnetic layers comprise magnets within one or more of their rotor slots, and wherein the non-magnetic layers do not comprise magnets within their rotor slots.

[0028] Option 2. A rotor according to Option 1, wherein:

[0029] A center line of each of the magnetic layers and a center line of each of the non-magnetic layers are radially aligned with a center line of the rotor pole corresponding thereto.

[0030] Option 3. A rotor according to Option 2, wherein:

[0031] The top end of each of the magnetic layers is radially inward of the top end of each of the non-magnetic layers, wherein the top ends of the magnetic layers and the non-magnetic layers are centered with respect to the center line of the rotor pole corresponding thereto.

[0032] Option 4. A rotor according to Option 3, wherein:

[0033] The rotor slots of the non-magnetic layer include a central rotor slot, a first outer rotor slot, and a second outer rotor slot, wherein a first central end of the central rotor slot is separated from the first outer rotor slot by a first side web, and a second central end of the central rotor slot is separated from the second outer rotor slot by a second side web, wherein the first side web and the second side web are part of the rotor core.

[0034] Option 5. A rotor according to Option 4, wherein:

[0035] A first peripheral end of the first outer rotor slot is separated from an outer periphery of the rotor core by a first outer bridge, and a first inner end of the first outer rotor slot is separated from the central rotor slot by the first side web, wherein the first outer bridge is part of the rotor core; and

[0036] A second peripheral end of the second outer rotor slot is separated from the outer periphery by a second outer bridge, and a second inner end of the second outer rotor slot is separated from the central rotor slot by the second side web, wherein the second outer bridge is part of the rotor core.

[0037] Solution 6. A rotor according to Solution 5, wherein:

[0038] Each of the rotor poles includes a first nonmagnetic layer and a second nonmagnetic layer of the nonmagnetic layers; and

[0039] The top end of each of the first non-magnetic layers is outside the top end of each of the second non-magnetic layers.

[0040] Option 7. A rotor according to Option 6, wherein:

[0041] The first outer rotor slot, the second outer rotor slot, and the center rotor slot of the first nonmagnetic layer have a first parabolic thickness defined relative to an apex; and

[0042] The first outer rotor slot, the second outer rotor slot, and the center rotor slot of the second non-magnetic layer have a second parabolic thickness defined relative to the vertex.

[0043] Option 8. A rotor according to Option 7, wherein:

[0044] The first parabolic thickness and the second parabolic thickness are substantially equal.

[0045] Option 9. A rotor according to Option 7, wherein:

[0046] The thickness of the first side web of the first non-magnetic layer is thinner than the thickness of the first side web of the second non-magnetic layer; and

[0047] The thickness of the second side web of the first non-magnetic layer is thinner than the thickness of the second side web of the second non-magnetic layer.

[0048] Option 10. The rotor according to Option 7, wherein:

[0049] The thickness of the first outer bridge of the first non-magnetic layer is thinner than the thickness of the first outer bridge of the second non-magnetic layer; and

[0050] The thickness of the second outer bridge of the first non-magnetic layer is thinner than the thickness of the second outer bridge of the second non-magnetic layer.

[0051] Option 11. A rotor according to Option 3, wherein:

[0052] The rotor slots of the magnetic layer include a middle rotor slot, a first intermediate rotor slot, a second intermediate rotor slot, a first outer rotor slot, and a second outer rotor slot, wherein the first middle end of the middle rotor slot is separated from the first intermediate rotor slot by a first intermediate web, and the second middle end of the middle rotor slot is separated from the second intermediate rotor slot by a second intermediate web, wherein the first intermediate web and the second intermediate web are part of the rotor core.

[0053] Option 12. The rotor according to Option 11, wherein:

[0054] a first intermediate end of the first intermediate rotor slot being separated from a first inner end of the first outer rotor slot by a first outer web, and a first middle end of the first intermediate rotor slot being separated from the middle rotor slot by a first intermediate web, wherein the first outer web is part of the rotor core; and

[0055] The second middle end of the second middle rotor slot is separated from the second inner end of the second outer rotor slot by a second outer web, and the second middle end of the second middle rotor slot is separated from the middle rotor slot by the second middle web, wherein the second outer web is part of the rotor core.

[0056] Option 13. The rotor according to Option 12, wherein:

[0057] A first outer end of the first outer rotor slot is separated from an outer periphery of the rotor core by a first outer bridge, wherein the first outer bridge is a portion of the rotor core; and

[0058] A second outer end of the second rotor slot is separated from the outer periphery by a second outer bridge, wherein the second outer bridge is a part of the rotor core.

[0059] Option 14. The rotor according to Option 13, wherein:

[0060] Each of the rotor poles includes a third magnetic layer, a fourth magnetic layer, and a fifth magnetic layer among the magnetic layers; and

[0061] The top end of each of the third magnetic layers is outside the top end of each of the fourth magnetic layers, and the top end of each of the fourth magnetic layers is outside the top end of each of the fifth magnetic layers.

[0062] Option 15. The rotor according to Option 14, wherein:

[0063] The magnet is included in each of the middle rotor slots, and no magnet is included in any of the first outer rotor slot, the second outer rotor slot, the first middle rotor slot, and the second middle rotor slot.

[0064] Option 16. The rotor according to Option 15, wherein:

[0065] The first outer rotor slot, the second outer rotor slot, the first middle rotor slot, and the second middle rotor slot of the third magnetic layer have a third parabolic thickness defined relative to an apex;

[0066] The first outer rotor slot, the second outer rotor slot, the first middle rotor slot, and the second middle rotor slot of the fourth magnetic layer have a fourth parabolic thickness defined relative to the vertex; and

[0067] The first outer rotor slot, the second outer rotor slot, the first middle rotor slot, and the second middle rotor slot of the fifth magnetic layer have a fifth parabolic thickness defined relative to the vertex.

[0068] Option 17. The rotor according to Option 16, wherein:

[0069] The middle rotor slot of the third magnetic layer has a third rectangular shape;

[0070] The middle rotor slot of the fourth magnetic layer has a fourth rectangular shape; and

[0071] The middle rotor slot of the fifth magnetic layer has a fifth rectangular shape.

[0072] Option 18. The rotor according to Option 17, wherein:

[0073] The thickness of each of the third rectangular shape, the fourth rectangular shape, and the fifth rectangular shape is approximately equal; and

[0074] The width of each of the third rectangular shapes is narrower than the width of each of the fourth rectangular shapes, and the width of each of the fourth rectangular shapes is narrower than the width of each of the fifth rectangular shapes.

[0075] Solution 19. A rotor for an electric motor, the rotor comprising:

[0076] A rotor core having a plurality of circumferentially spaced rotor poles, wherein each rotor pole comprises a plurality of rotor slots arranged into a plurality of layers, the plurality of layers comprising:

[0077] a first non-magnetic layer having its rotor slots shaped to include a central rotor slot, a first outer rotor slot, and a second outer rotor slot;

[0078] a second non-magnetic layer having its rotor slots shaped to include a central rotor slot, a first outer rotor slot, and a second outer rotor slot;

[0079] a third magnetic layer, wherein the third magnetic layer has its rotor slots shaped to include a middle rotor slot, a first middle rotor slot, a second middle rotor slot, a first outer rotor slot, and a second outer rotor slot;

[0080] a fourth magnetic layer, wherein the fourth magnetic layer has its rotor slots shaped to include a middle rotor slot, a first middle rotor slot, a second middle rotor slot, a first outer rotor slot, and a second outer rotor slot;

[0081] a fifth magnetic layer, wherein the fifth magnetic layer has its rotor slots shaped to include a middle rotor slot, a first middle rotor slot, a second middle rotor slot, a first outer rotor slot, and a second outer rotor slot;

[0082] wherein the first non-magnetic layer and the second non-magnetic layer do not include a magnet; and

[0083] Wherein the third magnetic layer, the fourth magnetic layer and the fifth magnetic layer include a magnet in each of the middle rotor slots.

[0084] Solution 20. A means of transportation, comprising:

[0085] an electric motor configured to convert electrical power into mechanical power for the purpose of propelling the vehicle; and

[0086] Wherein, the electric motor comprises:

[0087] a stator comprising a plurality of stator windings configured to generate a rotating magnetic field (RMF);

[0088] A rotor configured to rotate within the stator in response to a torque induced by the RMF, wherein the rotor comprises a rotor core having a plurality of circumferentially spaced rotor poles, wherein each rotor pole comprises a plurality of rotor slots arranged into one or more magnetic layers and one or more non-magnetic layers, the magnetic layers comprising magnets within one or more of their rotor slots, and the non-magnetic layers comprising no magnets within their rotor slots.

[0089] These features and advantages of the present teaching, together with other features and advantages, can be readily apparent from the following detailed description of the mode for implementing the present teaching when understood in conjunction with the accompanying drawings. It should be understood that even though the following figures and embodiments may be described separately, their single features may also be combined into additional embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0091] Figure 1 A schematic diagram of an electric machine according to one non-limiting aspect of the present disclosure is illustrated.

[0092] Figure 2 A schematic diagram of a vehicle having an electric machine according to one non-limiting aspect of the present disclosure is illustrated.

[0093] Figure 3 A schematic diagram of a rotor lamination according to one non-limiting aspect of the present disclosure is illustrated.

[0094] Figure 4 Illustrated is a fragmentary schematic fragmentary view of one of the rotor poles according to a non-void aspect of the present disclosure.

[0095] Figure 5 A schematic diagram of a magnet having a rectangular piece is illustrated in accordance with one non-limiting aspect of the present disclosure.

[0096] Figure 6 A schematic diagram of a magnet having a triangular piece is illustrated in accordance with one non-limiting aspect of the present disclosure.

[0097] Figure 7 A schematic diagram of a magnet having triangular and trapezoidal pieces is illustrated in accordance with one non-limiting aspect of the present disclosure. DETAILED DESCRIPTION

[0098] As desired, detailed embodiments of the present disclosure may be disclosed herein; however, it is understood that the disclosed embodiments may be merely examples of the present disclosure, which may be embodied in various and alternative forms. The figures may not necessarily be drawn to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein may not need to be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to adopt the present disclosure in various ways.

[0099] Figure 1A schematic diagram of an electric machine 10 according to one non-limiting aspect of the present disclosure is illustrated. The electric machine 10 may be of a type that employs a rotor 12 to impart mechanical force to a load in proportion to its electrical excitation and / or to generate electrical energy in response to its rotation. At least in the illustrated configuration, the electric machine 10 may be referred to as an electric motor 10 operable for propulsion of a vehicle and / or regenerative braking. Figure 2 A schematic diagram of a vehicle 14 having an electric motor 10 is illustrated in accordance with one non-limiting aspect of the present disclosure. The electric motor 10 may be employed within the vehicle 14 to facilitate imparting mechanical force to a propulsion system, powertrain, or drivetrain 16 operable to propel or otherwise drive the vehicle 14. The vehicle 14 is illustrated as a hybrid type due to the powertrain 12 optionally including an internal combustion engine (ICE) 18. The powertrain 16 may include a transmission, a drive shaft, a differential, an axle, and / or other components to facilitate imparting rotational force from the rotor 10 (see FIG. 1 ). Figure 1 ) coupled to a rotor shaft 30 to deliver power to wheels 20, 22, 24, 26. Vehicle 14 is shown as including a power system 12 that is operable with front wheels 20, 24 for non-limiting purposes, as the present disclosure fully contemplates its use and application to four-wheel drive vehicles and other non-automotive types of vehicles.

[0100] Back to Figure 1 , the electric motor 10 may include a housing 32 that is configured to support a rearward end (not shown) of the rotor shaft 30 while permitting the rotor 10 to rotate relative to the stator 36 within the air gap 34. The stator 36 may be disposed annularly around the rotor 10 for the purpose of generating a rotating magnetic field (RMF), which, as will be appreciated by those skilled in the art, may be used to impart a rotational torque sufficient to rotate the rotor 10. Although not shown in detail, the stator 36 may include stator windings or other features that can be electrically excited for the purpose of controlling the RMF and resulting rotation of the rotor 10. As shown in Figure 3 As shown in the schematic end view of , the rotor 10 may include a plurality of rare earth (RE), heavy rare earth (HRE), and / or other types of permanent magnets 40 capable of providing a persistent magnetic field (which may be simply referred to as magnets 40). One non-limiting aspect of the present disclosure contemplates that the rotor 10 is formed of a plurality of laminations stacked axially along a rotating path A in a side-by-side facing relationship to have a generally annular shape, wherein each lamination optionally includes Figure 3 The rotor 10 configuration shown in FIG. The rotor 10 may be advantageously constructed in such a manner to obtain the performance benefits associated with using such magnets 40 while also minimizing the materials, resources, etc. consumed in manufacturing or otherwise utilizing the magnets 40 .

[0101] Figure 34, may represent a lamination of the rotor 10, so that multiple, optionally identical, laminations may be stacked together to form the entire rotor 10. The rotor 10 may be formed of steel or other suitable material to include a rotor core 44 having a plurality of rotor slots S and an arcuate inner surface 46 configured for coupling with the rotor shaft 30. The inner surface 46 may optionally be formed with different shapes or configurations, depending on the desired coupling with the rotor shaft 30 or other loads placed thereon. The rotor 10 is shown as being constructed with six circumferentially spaced rotor poles P1, P2, P3, P4, P5, P6 (these rotor poles have a centerline C centered relative to the magnet 40), which may be referred to as a six-pole configuration. This is done for non-limiting purposes, as the present disclosure fully contemplates that the rotor 10 is similarly constructed to support configurations with more or fewer rotor poles P1, P2, P3, P4, P5, P6. Figure 4 A fragmentary schematic fragmentary diagram of one of the rotor poles P2 according to one non-empty aspect of the present disclosure is illustrated. Each of the poles of the rotor 10 can be constructed in a similar manner, namely where the rotor slots S are arranged into multiple layers L. While the use of more or fewer layers L is contemplated, it is believed that the illustrated use of the first layer L1, the second layer L2, the third layer L3, the fourth layer L4, and the fifth layer L5 is beneficial to balance the performance gains provided by the magnets 40 with respect to the materials, resources, etc. consumed in manufacturing or otherwise utilizing these magnets.

[0102] The first layer L1 and the second layer L2 may each include a central rotor slot 46A, 46B, a first outer rotor slot 48A, 48B, and a second outer rotor slot 50A, 50B. Since the slots of the rotor 10 do not include magnets 40, the first layer L1 and the second layer L2 may be referred to as non-magnetic layers. Each of the rotor slots 46A, 46B, 48A, 48B, 50A, 50B of the first non-magnetic layer L1 and the second non-magnetic layer L2 may be an air gap or a gap incorporated in the rotor core 44. The third layer L3, the fourth layer L4, and the fifth layer L5 may each include a middle rotor slot 56A, 56B, 56C, a first intermediate rotor slot 58A, 58B, 58C, a second intermediate rotor slot 60A, 60B, 60C, a first outer rotor slot 62A, 62B, 62C, and a second outer rotor slot 64A, 64B, 64C. The third layer L3, the fourth layer L4, and the fifth layer L5 may be referred to as magnetic layers due to the inclusion of magnets 40 in one or more of their rotor slots, which are shown for exemplary purposes as corresponding to the magnets included in the middle rotor slots 56A, 56B, 56C. Similar to the first layer L1 and the second layer L2, the remaining rotor slots 58A, 58B, 58C, 60A, 60B, 60C, 62A, 62B, 62C, 64A, 64B, 64C of the third layer L3, the fourth layer L4, and the fifth layer L5 may be air gaps or voids in the rotor 10 without magnets 40. The top or radially inward point A1, A2, A3, A4, A5 of each of the layers L1, L2, L3, L4, L5 can be centered relative to the center line of the corresponding pole P1, P2, P3, P4, P5, P6. In the illustrated configuration, this includes: the top A5 of the fifth layer L5 is on the inner side of the top A4 of the fourth layer L4, the top A4 of the fourth layer L4 is on the inner side of the top A3 of the third layer L3, the top A3 of the third layer L3 is on the inner side of the top A2 of the second layer L2, and the top A2 of the second layer L2 is on the inner side of the top A1 of the first layer L1.

[0103] Regarding the non-magnetic layer, the first center end of the central rotor slot 46A, 46B can be separated from the first outer rotor slot 48A, 48B by the first side web 70A, 70B, and the second center end of the central rotor slot 46A, 46B can be separated from the second outer rotor slot 50A, 50B by the second side web 72A, 72B. The first side web 70A, 70B and the second side web 72A, 72B can be constructed as a part of the rotor core 44 in this way. The first peripheral end of the first outer rotor slot 48A, 48B can be separated from the outer periphery O of the rotor core 44 by the first outer bridge 74A, 74B, and the first inner end of the first outer rotor slot is separated from the central rotor slot 46A, 46B by the first side web 70A, 70B. The second peripheral ends of the second outer rotor slots 50A, 50B can be separated from the outer periphery O by the second outer bridges 76A, 76B, and the second inner ends of the second outer rotor slots 46A, 46B can be separated from the central rotor slot by the second side webs. The first outer bridges 74A, 74B and the second outer bridges 76A, 76B can be constructed as part of the rotor core 44 in this manner. The rotor 10 (or more specifically, each rotor core lamination stacked together as part of the rotor 10) can be individually formed into the illustrated structure, such as by stamping or other manufacturing processes, whereby the slots of the rotor 10 can be carved out of a single sheet of material comprising the rotor core 44 laminations.

[0104] With respect to magnetic layers L3, L4, L5, the first middle ends of the middle rotor slots 56A, 56B, 56C may be separated from the first middle rotor slots 58A, 58B, 58C by first middle webs 80A, 80B, 80C, and the second middle ends of the middle rotor slots 56A, 56B, 56C may be separated from the second middle rotor slots 60A, 60B, 60C by second middle webs 82A, 82B, 82C. The first middle webs 80A, 80B, 80C and the second middle webs 82A, 82B, 82C may be constructed as part of the rotor core 44 in this manner. The first intermediate ends of the first intermediate rotor slots 58A, 58B, 58C may be separated from the first inner ends of the first outer rotor slots 62A, 62B, 62C by the first outer webs 86A, 86B, 86C, and the first middle ends of the first intermediate rotor slots 58A, 58B, 58C may be separated from the middle rotor slots 56A, 56B, 56C by the first middle webs 80A, 80B, 80C. The second intermediate ends of the second intermediate rotor slots 60A, 60B, 60C may be separated from the second inner ends of the second outer rotor slots 64A, 64B, 64C by the second outer webs 88A, 88B, 88C, and the second middle ends of the second intermediate rotor slots 60A, 60B, 60C may be separated from the middle rotor slots by the second middle webs 82A, 82B, 82C. The first outer web 86A, 86B, 86C and the second outer web 88A, 88B, 88C may be constructed in this manner as part of the rotor core 44. The first outer end of the first outer rotor slot 62A, 62B, 62C may be separated from the outer periphery O by the first outer bridge 90A, 90B, 90C. The second outer end of the second outer rotor slot 64A, 64B, 64C may be separated from the outer periphery O by the second outer bridge 92A, 92B, 92C. The first outer bridge 90A, 90B, 90C and the second outer bridge 92A, 92B, 92C may be constructed in this manner as part of the rotor core 44.

[0105] As described, the proposed rotor design can utilize multiple different magnets 40 (material properties, shapes or sizes) to form certain magnetic poles in the PM synchronous machine 10. The magnet discretization can be equal or unequal in size, and the magnets 40 can be included in different layers of different rotor laminations in different ways, that is, the magnets 40 can be dispersed throughout the layers L1, L2, L3, L4, L5, and / or the layers L1, L2, L3, L4, L5 themselves can be constructed in a different way than that illustrated for other laminations stacked together as part of the rotor 10. The shape and size determination of the rotor slots, webs and bridges can similarly vary across different layers L1, L2, L3, L4, L5, or can be the same, depending on their location in the rotor core 44 and the resulting impact on optimizing both electromagnetic and mechanical integrity. The proposed rotor 12 and the resulting motor 10 can utilize magnets 40 of different types and shapes to improve the electromagnetic performance of the motor 10 in order to achieve average torque and reduce torque ripple. Empty rotor slots (i.e., rotor slots lacking magnets 40 ) may be designed and incorporated to act as air barriers near the outer perimeter or radius of the rotor core 44 , which may be beneficial in improving demagnetization performance and thereby limiting HRE content in the rotor 10 , which may optionally permit or enable the use of non-HRE grade magnets 40 .

[0106] While the present disclosure contemplates a wide variety of configurations, shapes, sizes, orientations, etc. of rotor slots, it is believed that the illustrated use of substantially parabolic magnetic layers L3, L4, L5 and non-magnetic layers L1, L2 is particularly beneficial for the outer non-magnetic layers to provide flux barriers and other performance enhancements that help minimize the use of magnets 40. The first outer rotor slot 48A, the second outer rotor slot 50A, and the center rotor slot 46A of the first non-magnetic layer L1 may have a first parabolic thickness T1 defined relative to the vertex V, and the first outer rotor slot 48B, the second outer rotor slot 50B, and the center rotor slot 46B of the second non-magnetic layer L2 may have a second parabolic thickness T2 defined relative to the vertex V. The first parabolic thickness T1 and the second parabolic thickness T2 are shown as being substantially equal in proportion to each other, with their widths W1, W2 varying in the illustrated manner based on the relative distance from the vertex V. The thickness of the first side web 70A of the first nonmagnetic layer L1 may be thinner than the thickness of the first side web 70B of the second nonmagnetic layer L2, and the thickness of the second side web 72A of the first nonmagnetic layer L1 may be thinner than the thickness of the second side web 72B of the second nonmagnetic layer L2. Similarly, the thickness of the first outer bridge 74A of the first nonmagnetic layer L1 may be thinner than the thickness of the first outer bridge 74B of the second nonmagnetic layer L2, and the thickness of the second outer bridge 76A of the first nonmagnetic layer L1 may be thinner than the thickness of the second outer bridge 76B of the second nonmagnetic layer L2.

[0107] The first outer rotor slot 62A, the second outer rotor slot 64A, the first intermediate rotor slot 58A, and the second intermediate rotor slot 60A of the third magnetic layer L3 may have a third parabolic thickness T3 defined relative to the vertex V, the first outer rotor slot 62B, the second outer rotor slot 64B, the first intermediate rotor slot 58B, and the second intermediate rotor slot 60B of the fourth magnetic layer L4 may have a fourth parabolic thickness T4 defined relative to the vertex V, and the first outer rotor slot 62C, the second outer rotor slot 64C, the first intermediate rotor slot 58C, and the second intermediate rotor slot 60C of the fifth magnetic layer L5 may have a fifth parabolic thickness T5 defined relative to the vertex V. The third parabolic thickness T3, the fourth parabolic thickness T4, and the fifth parabolic thickness T5 are shown as being approximately equal in proportion to each other, with their widths W3, W4, W5 varying in the illustrated manner based on the relative distance from the vertex V. The middle rotor slot 56A of the third magnetic layer L3 may have a third rectangular shape, the middle rotor slot 56B of the fourth magnetic layer L4 may have a fourth rectangular shape, and the middle rotor slot 56C of the fifth magnetic layer L5 may have a fifth rectangular shape. As shown, the thickness of each of the third rectangular shape, the fourth rectangular shape, and the fifth rectangular shape may be approximately equal, wherein the width of the third rectangular shape may be optionally narrower than the width of each of the fourth rectangular shapes, and the width of the fourth rectangular shape may be optionally narrower than the width of the fifth rectangular shape.

[0108] The magnets 40 are shown as being proportionally sized relative to the corresponding mid-rotor slots, ie, for each magnet, the width, thickness, and depth are substantially equal to the corresponding mid-rotor slot. This is done for the non-limiting purpose that the present disclosure fully contemplates magnets 40 having other configurations. Figure 5 A schematic diagram of a magnet 40 including various rectangular pieces is illustrated in accordance with one non-limiting aspect of the present disclosure. Figure 6 A schematic diagram of a magnet 40 including various triangular pieces is illustrated in accordance with one non-limiting aspect of the present disclosure. Figure 7 The magnet 40 including a triangular piece and a trapezoidal piece according to one non-limiting aspect of the present disclosure is illustrated. Using a magnet 40 including a plurality of magnetic pieces can be advantageous in minimizing the size of each of the magnets 40, i.e., Figure 5-7 The magnets 40 in the embodiment may individually have relatively small dimensions, rather than having Figure 4 The larger magnet 40 is shown in FIG.

[0109] The terms "comprise", "include" and "have" are inclusive and therefore specify the presence of the stated features, steps, operations, elements or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements or parts. Where possible, the order of steps, processes and operations can be changed, and additional or alternative steps can be adopted. As used in this specification, the term "or" includes any one and all combinations of the associated listed items. The term "any of" is understood to include any possible combination of the cited items, including "any of" the cited items. "One", "one", "the", "at least one" and "one or more" are used interchangeably to indicate that there is at least one of the items. Unless the context clearly indicates otherwise, there may be multiple such items. Unless otherwise clearly or clearly indicated by the context (including the attached claims), all parameter (e.g., quantity or condition) values ​​will be understood to be modified by the term "approximately" in all cases, regardless of whether "approximately" actually appears before the value. A component that is "configured to" perform a specified function is able to perform the specified function without modification, rather than just having the potential to perform the specified function after further modification. In other words, the described hardware, when expressly configured to perform the specified functions, is selected, created, implemented, utilized, programmed, and / or designed specifically for the purpose of performing the specified functions.

[0110] Although various embodiments have been described, the description is intended to be exemplary rather than restrictive, and it will be apparent to those of ordinary skill in the art that within the scope of the embodiments, there are still more embodiments and implementations that are possible. Unless specifically limited, any feature of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment. Therefore, the embodiments will not be limited except according to the attached claims and their equivalents. Moreover, various modifications and changes may be made within the scope of the attached claims. Although several modes for implementing many aspects of the present teachings have been described in detail, those skilled in the art who are familiar with the fields to which these teachings relate will recognize various alternative aspects for practicing the present teachings within the scope of the attached claims. It is expected that all matters contained in the above description or shown in the drawings should be interpreted as illustrating and illustrating the entire range of alternative embodiments that ordinary skill in the art will recognize, such as implied by the included content, structurally and / or functionally equivalent to the included content, or otherwise presented as obvious based on the included content, and are not recognized as being limited to those embodiments that are explicitly depicted and / or described.

Claims

1. A rotor for an electric motor, the rotor comprising: A rotor core having a plurality of circumferentially spaced rotor poles, wherein each rotor pole comprises a plurality of rotor slots arranged into one or more magnetic layers and one or more non-magnetic layers, wherein the magnetic layers comprise magnets within one or more of their rotor slots, and wherein the non-magnetic layers do not comprise magnets within their rotor slots.

2. The rotor according to claim 1, wherein: A center line of each of the magnetic layers and a center line of each of the non-magnetic layers are radially aligned with a center line of the rotor pole corresponding thereto.

3. The rotor according to claim 2, wherein: The top end of each of the magnetic layers is radially inward of the top end of each of the non-magnetic layers, wherein the top ends of the magnetic layers and the non-magnetic layers are centered with respect to the center line of the rotor pole corresponding thereto.

4. The rotor according to claim 3, wherein: The rotor slots of the non-magnetic layer include a central rotor slot, a first outer rotor slot, and a second outer rotor slot, wherein a first central end of the central rotor slot is separated from the first outer rotor slot by a first side web, and a second central end of the central rotor slot is separated from the second outer rotor slot by a second side web, wherein the first side web and the second side web are part of the rotor core.

5. The rotor according to claim 4, wherein: A first peripheral end of the first outer rotor slot is separated from an outer periphery of the rotor core by a first outer bridge, and a first inner end of the first outer rotor slot is separated from the central rotor slot by the first side web, wherein the first outer bridge is part of the rotor core; and A second peripheral end of the second outer rotor slot is separated from the outer periphery by a second outer bridge, and a second inner end of the second outer rotor slot is separated from the central rotor slot by the second side web, wherein the second outer bridge is part of the rotor core.

6. The rotor according to claim 5, wherein: Each of the rotor poles includes a first nonmagnetic layer and a second nonmagnetic layer of the nonmagnetic layers; and The top end of each of the first non-magnetic layers is outside the top end of each of the second non-magnetic layers.

7. A rotor according to claim 6, wherein: The first outer rotor slot, the second outer rotor slot, and the center rotor slot of the first nonmagnetic layer have a first parabolic thickness defined relative to an apex; and The first outer rotor slot, the second outer rotor slot, and the center rotor slot of the second non-magnetic layer have a second parabolic thickness defined relative to the vertex.

8. A rotor according to claim 7, wherein: The first parabolic thickness and the second parabolic thickness are substantially equal.

9. A rotor for an electric motor, the rotor comprising: A rotor core having a plurality of circumferentially spaced rotor poles, wherein each rotor pole comprises a plurality of rotor slots arranged into a plurality of layers, the plurality of layers comprising: a first non-magnetic layer having its rotor slots shaped to include a central rotor slot, a first outer rotor slot, and a second outer rotor slot; a second non-magnetic layer having its rotor slots shaped to include a central rotor slot, a first outer rotor slot, and a second outer rotor slot; a third magnetic layer, wherein the third magnetic layer has its rotor slots shaped to include a middle rotor slot, a first middle rotor slot, a second middle rotor slot, a first outer rotor slot, and a second outer rotor slot; a fourth magnetic layer, wherein the fourth magnetic layer has its rotor slots shaped to include a middle rotor slot, a first middle rotor slot, a second middle rotor slot, a first outer rotor slot, and a second outer rotor slot; a fifth magnetic layer, wherein the fifth magnetic layer has its rotor slots shaped to include a middle rotor slot, a first middle rotor slot, a second middle rotor slot, a first outer rotor slot, and a second outer rotor slot; wherein the first non-magnetic layer and the second non-magnetic layer do not include a magnet; and Wherein the third magnetic layer, the fourth magnetic layer and the fifth magnetic layer include a magnet in each of the middle rotor slots.

10. A means of transport, comprising: an electric motor configured to convert electrical power into mechanical power for the purpose of propelling the vehicle; and Wherein, the electric motor comprises: a stator comprising a plurality of stator windings configured to generate a rotating magnetic field (RMF); A rotor configured to rotate within the stator in response to a torque induced by the RMF, wherein the rotor comprises a rotor core having a plurality of circumferentially spaced rotor poles, wherein each rotor pole comprises a plurality of rotor slots arranged into one or more magnetic layers and one or more non-magnetic layers, the magnetic layers comprising magnets within one or more of their rotor slots, and the non-magnetic layers comprising no magnets within their rotor slots.

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