Segmented internal permanent magnet motor

Abstract

An internal permanent magnet machine includes a stator and a rotor. The rotor has a rotor core with slots extending between opposite ends thereof. The slots contain segmented magnet assemblies comprising magnet segments of different magnetic materials. The segmented magnet assembly may be divided radially, axially, circumferentially, or in a combination thereof, and may include outer magnet segments made of a first magnetic material and inner magnet segments made of a second magnetic material. In addition, the segmented magnet assembly includes magnetic poles aligned in a radial, axial, or circumferential direction.

Description

Technical Field

[0001] The present disclosure relates to interior permanent magnet (IPM) machines. More particularly, the present disclosure relates to pole arrangements in IPM machines. Background Art

[0002] High output motors, such as IPM alternating current (AC) motors used in electrified vehicle powertrains, can employ rare earth magnets, such as neodymium and samarium cobalt magnets. Enhanced neodymium magnetic properties, such as higher resistance to demagnetization (coercivity), improved temperature stability, or better performance under extreme conditions, can be achieved by adding heavy rare earth (HRE) elements including dysprosium (Dy), terbium (Tb), and gadolinium (Gd). HRE magnets may be sensitive to supply volatility of HRE elements. Some mitigation pathways for HRE supply volatility factors may come from improvements in the materials field, such as boundary diffusion processes that minimize material requirements. Due to HRE supply volatility factors, among others, it is generally desirable to reduce the HRE content of such magnets. Summary of the invention

[0003] In an exemplary embodiment, an interior permanent magnet electric machine may include a rotor core having axially opposed ends and a plurality of slots, each slot extending through the rotor core between the axially opposed ends and including a segmented magnet assembly including at least one magnet segment of a first magnetic material and at least one magnet segment of a second magnetic material.

[0004] In addition to one or more features described herein, the segmented magnet assembly is segmented in a radial direction relative to the axis of rotation of the rotor core.

[0005] In addition to one or more features described herein, the segmented magnet assembly includes radially outer magnet segments of a first magnetic material at radial ends of the segmented magnet assembly and at least one inner magnet segment of a second magnetic material radially between the radially outer magnet segments of the first magnetic material.

[0006] In addition to one or more features described herein, the first magnetic material includes a heavy rare earth magnetic material and the second magnetic material includes a non-heavy rare earth magnetic material.

[0007] In addition to one or more features described herein, the segmented magnet assembly is segmented in an axial direction relative to the axis of rotation of the rotor core.

[0008] In addition to one or more features described herein, the segmented magnet assembly may include axially outer magnet segments of a first magnetic material at axial ends of the segmented magnet assembly and at least one inner magnet segment of a second magnetic material axially between the axially outer magnet segments of the first magnetic material.

[0009] In addition to one or more features described herein, the first magnetic material may include a heavy rare earth magnetic material and the second magnetic material may include a non-heavy rare earth magnetic material.

[0010] In addition to one or more features described herein, the segmented magnet assembly is segmented in a circumferential direction relative to the axis of rotation of the rotor core.

[0011] In addition to one or more features described herein, the segmented magnet assembly may include magnetic poles aligned in an axial direction relative to an axis of rotation of the rotor core.

[0012] In addition to one or more features described herein, the segmented magnet assembly may include magnetic poles aligned in a radial direction relative to the axis of rotation of the rotor core.

[0013] In addition to one or more features described herein, the segmented magnet assembly may include magnetic poles aligned in a circumferential direction relative to an axis of rotation of the rotor core.

[0014] In addition to one or more features described herein, the first magnetic material may include a heavy rare earth magnetic material and the second magnetic material may include a non-heavy rare earth magnetic material.

[0015] In addition to one or more features described herein, the segmented magnet assembly may also include axially outer magnet segments of a first magnetic material at axial ends of the segmented magnet assembly, and at least one inner magnet segment of a second magnetic material axially between the axially outer magnet segments of the first magnetic material.

[0016] In addition to one or more features described herein, the first magnetic material may include a heavy rare earth magnetic material and the second magnetic material may include a non-heavy rare earth magnetic material.

[0017] In addition to one or more features described herein, at least one of the radially outer magnet segments of the first magnetic material and the at least one inner magnet segment of the second magnetic material at the radial ends of the segmented magnet assembly are trapezoidal in shape.

[0018] In addition to one or more features described herein, at least one of the radially outer magnet segments of the first magnetic material at the radial ends of the segmented magnet assembly is triangular in shape.

[0019] In another exemplary embodiment, an internal permanent magnet electric machine may include a stator and a rotor, the rotor including a rotor core having axially opposite ends and a plurality of slots, each slot extending through the rotor core between the axially opposite ends and including a segmented magnet assembly, the segmented magnet assembly including at least one magnet segment of a first magnetic material and at least one magnet segment of a second magnetic material, wherein the segmented magnet assembly is segmented in a radial direction relative to an axis of rotation of the rotor core and includes radially outer magnet segments of the first magnetic material at radial ends of the segmented magnet assembly and at least one inner magnet segment of the second magnetic material radially between the radially outer magnet segments of the first magnetic material, the segmented magnet assembly also including magnetic poles aligned in a circumferential direction relative to the axis of rotation of the rotor core.

[0020] In addition to one or more features described herein, the first magnetic material may include a heavy rare earth magnetic material and the second magnetic material may include a non-heavy rare earth magnetic material.

[0021] In addition to one or more features described herein, the first magnetic material can include a non-heavy rare earth magnetic material and the second magnetic material can include a heavy rare earth magnetic material.

[0022] In yet another exemplary embodiment, an electrified powertrain for a vehicle may include: a battery pack; a traction power inverter module (“TPIM”) connected to the battery pack and configured to change a direct current (“DC”) voltage from the battery pack to an alternating current (“AC”) voltage; and a rotating electric machine including a stator excited by the AC voltage from the TPIM; a rotor including a rotor core having axially opposite ends and a plurality of slots, each slot extending through the rotor core between the axially opposite ends and including a segmented magnet assembly including at least one magnet segment of a first magnetic material and at least one magnet segment of a second magnetic material , wherein the segmented magnet assembly is segmented in a radial direction relative to the rotation axis of the rotor core and includes radially outer magnet segments of a first magnetic material at radial ends of the segmented magnet assembly and at least one inner magnet segment of a second magnetic material radially between the radially outer magnet segments of the first magnetic material, the segmented magnet assembly also includes magnetic poles, a rotor shaft and a transmission device, the magnetic poles are aligned in a circumferential direction relative to the rotation axis of the rotor core, the rotor shaft is connected to the rotor and is configured to rotate with the rotor around the rotation axis when the stator is energized, and the transmission device is coupled to the rotor shaft and powered by the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features, advantages and details appear, by way of example only, from the following detailed description, which refers to the accompanying drawings, in which:

[0024] Figure 1An electrified powertrain according to one or more embodiments is shown;

[0025] Figure 2 illustrates various features of an interior permanent magnet rotor according to one or more embodiments;

[0026] FIG. 3A to FIG. 3E illustrates various embodiments of segmented magnet assemblies according to one or more embodiments;

[0027] Figures 4A-4C shows an end view of a rotor including a rotor core and segmented internal permanent magnets according to one or more embodiments; and

[0028] Figure 5 An alternative embodiment of a segmented magnet assembly according to one or more embodiments is illustrated. DETAILED DESCRIPTION

[0029] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. Throughout the drawings, corresponding reference numerals indicate identical or corresponding parts and features. The description of components and features in one drawing is understood to apply to components and features in other drawings sharing the same reference numerals, as long as such components and features cannot be otherwise distinguished by one of ordinary skill in the art through inspection of the drawings or through additional written descriptions herein.

[0030] Referring to the drawings, wherein like reference numerals designate like or identical components throughout the several views, Figure 1 An electrified powertrain 10 (e.g., for use on an exemplary motor vehicle 11) is schematically depicted in FIG. 1 . The powertrain 10 includes a rotating electric machine 12 having a rotor 12R and a stator 12S. The rotor 12R may include internal permanent magnets. When the stator 12S is energized, the rotor 12R provides motor torque to a transmission 20 (e.g., a stepper gear automatic transmission). Although omitted for simplicity of illustration, the electrified powertrain 10 may also include an internal combustion engine configured to generate engine torque. When so equipped, the generated engine torque may be selectively provided to the transmission 20 alone or in combination with the motor torque from the electric machine 12.

[0031] when Figure 1When the vehicle 11 is implemented as a hybrid electric vehicle, the motor 12 and / or the engine may provide power to the transmission 20. Alternatively, the vehicle 11 may be a battery electric vehicle, in which case the transmission 20 may be powered solely by motor torque from the motor 12. The disclosed improvements relate to the construction of the motor 12 and may be implemented in hybrid electric vehicle (HEV) embodiments and electric vehicle (EV) embodiments of the vehicle 11, without limitation, as well as in non-vehicle applications such as power plants, hoists, mobile platforms, and robots. Although the motor 12 is described as a rotary motor, certain applications such as rail propulsion systems may employ a linear motor in which the rotor may be embodied as a linear equivalent with internal permanent magnets, as is known in the art.

[0032] Continue to refer Figure 1 In an exemplary vehicle 11 of FIG. 1 , the electrified powertrain 10 may include an alternating current (AC) voltage bus 13. The AC voltage bus 13 may be selectively energized via a traction power inverter module (TPIM) 28, which is DC coupled to a high voltage (HV) battery pack 24, such as lithium-ion, lithium-sulfur, nickel-metal hydride, or other high energy voltage source. The AC voltage bus 13 provides an AC bus voltage (VAC) and conducts AC current to or from the motor 12. When operating in a drive or motor drive mode, the motor torque from the energized motor 12 is transferred to a rotor shaft 125 of the rotor 12R, where the rotor shaft 125 is journaled, splined, or otherwise connected to the rotor 12R. The motor torque is then directed to a coupled load, such as a transmission 20 and / or one or more road wheels 22.

[0033] The HV battery pack can be DC-coupled to the TPIM 28 via a relatively high DC voltage bus (e.g., DC link) 15 at a relatively high DC voltage (VDC). The electrified powertrain 10 can also include a DC-DC converter 26 configured to reduce or increase the relatively high DC bus voltage VDC as needed. The DC-DC converter 26 is connected between the battery pack 24 and the relatively low DC voltage bus 16. In some configurations, an auxiliary battery pack 124 can be connected to the DC-DC converter 26 across the relatively low DC voltage bus 16. The auxiliary battery pack 124 can be implemented as a lead-acid battery or a battery composed of another application-appropriate chemistry and is configured to store, for example, a 12-15V auxiliary voltage (VAUX) or supply, for example, a 12-15V auxiliary voltage (VAUX) to one or more connected auxiliary devices (not shown).

[0034] The rotor 12R of the electric machine 12 is positioned adjacent to the stator 12S and separated from the stator 12S by an air gap. The stator 12S and the rotor 12R may be constructed from a stack of thin laminations (e.g., electrical steel or another ferrous material, with each lamination typically being about 0.2 mm-0.5 mm thick, as will be understood by one of ordinary skill in the art). The laminations may be cut into their finished shape by a punch and die, or may be cut by a laser or by wire electrical discharge machining.

[0035] Figure 1 The rotor 12R schematically shown in Figure 1 includes internal rotor slots characterized by voids in the electrical steel of the laminations. Such rotor slots can provide flux barriers inside the rotor 12R and can include other rotor features as further described herein. According to certain embodiments, the rotor slots can be partially or completely filled with permanent magnets (PM).

[0036] Figure 2 Depicts the internal permanent magnet (IPM) rotating machine Figure 1 An exemplary rotor core 201 of a rotor 12R. The rotor core 201 may be constructed from a stack of thin laminations (e.g., electrical steel or another ferrous material, wherein each lamination is typically about 0.2 mm-0.5 mm thick, as will be understood by one of ordinary skill in the art). The complete rotor core 201 may include a plurality of sub-cores 201A or a single stack of laminations. References to a rotor core herein may refer to a plurality of sub-cores 201A or a single stack of laminations. The laminations may be cut into their finished shape by punches and dies, or may be cut by a laser or by wire electrical discharge machining. The rotor core 201 may alternatively be manufactured, such as by molding from sintered powder metal and a binder under heat and pressure, or as a plurality of sub-cores or a single molded structure. As Figure 1 As shown, the stator according to a non-limiting exemplary embodiment is arranged concentrically around the rotor 12R, such that the rotor 12R is surrounded by the stator 12S. In such an embodiment, the air gap G is a radial air gap, and the electric machine 12 is embodied as a radial flux type electric machine. However, other embodiments of the rotating electric machine can be implemented, in which, for example, the relative positions of the rotor 12R and the stator 12S are reversed (i.e., internal stator) or the air gap is axial. For consistency of description, this document will describe the rotor 12R as being radially located inside the stator 12S. Figure 1 The present invention further provides an embodiment of the present invention without limiting the configuration to this configuration.

[0037] Figure 1 The stator 125 may include radially projecting stator teeth extending inwardly from a cylindrical stator core, such as Figure 5That is, the stator teeth extend from the stator core toward the rotor 12R. The inner diameter surface of the stator 12S is the radially innermost surface of the stator teeth, which faces or is opposite to the outer peripheral surface 205 of the rotor 12R in a spaced adjacent manner to form a Figure 1 The air gap G is shown. Adjacent stator teeth are separated from each other by corresponding stator slots, as will be understood by those of ordinary skill in the art. The stator slots enclose electrical conductors, which are typically copper wires, copper rods, or hairpin conductors. Such conductors together form the stator winding. When the stator winding is composed of Figure 1 The multi-phase output voltages of the TPIM 28 shown are sequentially energized to generate a rotating stator magnetic field. Stator magnetic poles formed by the resulting rotating stator magnetic field interact with rotor magnetic poles to rotate the rotor 12R about the rotation axis 203 of the rotor core 201.

[0038] exist Figure 2 In an IPM rotary machine embodiment, the rotor core 201 may include a plurality of slots 207 extending axially through the rotor core 201 between opposite ends 209 of the rotor core 201. The slots may be substantially axially aligned between the opposite ends 209 of the rotor core, although the actual alignment may be skewed as is known in the art. When the rotor core 201 is aligned along the rotation axis 203 (such as at Figures 4A-4C When observed in the middle), the slot 207 can be elongated with a skewed alignment relative to the true radial alignment, as known in the art. References to the radial alignment or substantially radial alignment of the slot or permanent magnet herein are understood to refer to the true radial alignment or skewed radial alignment as known to those skilled in the art. In the embodiment shown in the figure, the slot 207 can be arranged in adjacent pairs of a "V" shaped pattern. In the embodiment shown in the figure, an inner "V" shaped pattern and an outer "V" shaped pattern of the slot 207 can be adopted, wherein the smaller slot 207 is closer to the outer peripheral surface 205 of the rotor core 201, and the larger slot 207 is closer to the rotation axis 203 of the rotor core 201. In an embodiment, each slot 207 can include a permanent magnet assembly 213. The permanent magnet assembly 213 can be continuous or segmented from one end of the rotor core 201 to the other end of the rotor core through the axial length of the corresponding slot 207. In an embodiment, each sub-core 201A can include a corresponding permanent magnet assembly 213.

[0039] The permanent magnet assembly 213 may be collectively referred to herein as a rotor magnet, and may be composed of, for example, rare earth magnets (such as neodymium and samarium cobalt magnets) and heavy rare earth (HRE) magnets. As used herein, HRE magnets are understood to include heavy rare earth elements (e.g., dysprosium (Dy), terbium (Tb), and gadolinium (Gd), etc.), while non-HRE (NHRE) magnets are understood to not include heavy rare earth elements. The permanent magnet assembly 213 may be embedded in the corresponding slots 207 in the stack of each steel lamination of the rotor core 201. The number, type, position, and / or relative orientation of the rotor magnets ultimately affect the size and distribution of the magnetic flux in the ferrous material of the motor 12. In one embodiment, the poles of the rotor magnets may be axially aligned between the axial ends 213x (axial x-axis). In one embodiment, the poles of the rotor magnets may be circumferentially aligned between the circumferential ends 213y (circumferential y-axis). In one embodiment, the poles of the rotor magnets may be radially aligned between the radial ends 213z (radial z-axis).

[0040] Figures 3A-3E Various embodiments of magnet assemblies 213 configured using magnet segments made of different magnetic materials are depicted. Any segmented magnet assembly 213 can include at least two magnet segments of different magnetic materials, such as one neodymium magnet segment and one samarium cobalt magnet segment, or one HRE magnet segment and one NHRE magnet segment, or one neodymium magnet segment, one samarium cobalt magnet segment and one HRE magnet segment. Figure 3A An embodiment of a magnet assembly 213 that is radially segmented along a radial z-axis as depicted is shown. In the illustrated embodiment, four magnet segments are shown as exemplary, but two or more magnet segments may make up any given segmented magnet assembly 213. In the illustrated embodiment, there are two outer magnet segments 301 and two inner magnet segments 303. In one embodiment, the outer magnet segments 301 may be HRE magnet segments and the inner magnet segments 303 may be NHRE magnet segments, for example where higher operating temperatures may be expected at the radial ends 213z than at the center of the magnet assembly 213. In another embodiment, the outer magnet segments 301 may be NHRE magnet segments and the inner magnet segments 303 may be HRE magnet segments, for example where higher operating temperatures may be expected at the center of the magnet assembly 213 than at the radial ends 213z.

[0041] Figure 3BAn embodiment of a magnet assembly 213 that is axially segmented along an axial x-axis as depicted is shown. In the illustrated embodiment, four magnet segments are shown as exemplary, but two or more magnet segments may constitute any given segmented magnet assembly 213. In the illustrated embodiment, there are two outer magnet segments 305 and two inner magnet segments 307. In one embodiment, the outer magnet segments 305 may be HRE magnet segments and the inner magnet segments 307 may be NHRE magnet segments, for example where higher operating temperatures may be expected at the axial ends 213x than at the center of the magnet assembly 213. In another embodiment, the outer magnet segments 305 may be NHRE magnet segments and the inner magnet segments 307 may be HRE magnet segments, for example where higher operating temperatures may be expected at the center of the magnet assembly 213 than at the axial ends 213x.

[0042] Figure 3C An embodiment of a magnet assembly 213 that is circumferentially segmented along a circumferential y-axis as depicted is illustrated. In the illustrated embodiment, three magnet segments are shown as exemplary, but two or more magnet segments may make up any given segmented magnet assembly 213. In the illustrated embodiment, there are two outer magnet segments 321 and one inner magnet segment 323. In one embodiment, the outer magnet segments 321 may be HRE magnet segments and the inner magnet segments 323 may be NHRE magnets, for example where higher operating temperatures may be expected at the circumferential ends 213y of the magnet assembly 213 than at the center of the magnet assembly 213. In another embodiment, the outer magnet segments 321 may be NHRE magnet segments and the inner magnet segments 323 may be HRE magnet segments, for example where higher operating temperatures may be expected at the center of the magnet assembly 213 than at the circumferential ends 213y.

[0043] Figure 3D An embodiment of a magnet assembly 213 is shown, and as shown, the magnet assembly 213 is segmented radially along the radial z-axis and axially along the axial x-axis. In the illustrated embodiment, five magnet segments are shown as an example. In the illustrated embodiment, there are two outer magnet segments 309 at the radial end 213z, two outer magnet segments 311 at the axial end 213x, and one inner magnet segment 313 at the axial end 213x. In one embodiment, for example, where it is expected that the operating temperature at the radial end 213z and the axial end 213x is higher than at the center of the magnet assembly 213, the outer magnet segments 309 and 311 can be HRE magnet segments, and the inner magnet segment 313 can be NHRE magnet segments. In another embodiment, for example, where it is expected that the operating temperature at the center of the magnet assembly 213 is higher than at the radial end 213z and the axial end 213x, the outer magnet segments 309 and 311 can be NHRE magnet segments, and the inner magnet segment 313 can be HRE magnet segments.

[0044] Figure 3E An embodiment of a magnet assembly 213 is shown, which is segmented radially along the radial z-axis and axially along the axial x-axis as shown. In the illustrated embodiment, five magnet segments are shown as an example. In the illustrated embodiment, there are two outer magnet segments 315 at the radial end 213z, two outer magnet segments 317 at the axial end 213x, and two inner magnet segments 319 at the axial end 213x. In one embodiment, for example, where it is expected that the operating temperature at the radial end 213z and the axial end 213x is higher than that at the center of the magnet assembly 213, the outer magnet segments 315 and 317 can be HRE magnet segments, and the inner magnet segment 319 can be NHRE magnet segments. In another embodiment, for example, where it is expected that the operating temperature at the center of the magnet assembly 213 is higher than that at the radial end 213z and the axial end 213x, the outer magnet segments 315 and 317 can be NHRE magnet segments, and the inner magnet segment 319 can be HRE magnet segments.

[0045] Figures 4A-4C The diagram shows a schematic diagram of a structure including a plurality of components, as viewed along the rotation axis 203 and relative to the stator 125 and the air gap G. Figure 2 An end view of a rotor of rotor core 201 is shown in FIG. Figures 4A-4C Various embodiments of magnet assemblies 213 are shown, as shown, the magnet assemblies 213 are assembled within respective slots 207 and radially segmented along respective radial z-axes. Smaller slots 207A closer to the outer peripheral surface 205 of the rotor core 201 and larger slots 207B closer to the rotational axis 203 of the rotor core 201 are shown. FIG. 4A to FIG. 4C A corresponding embodiment of a magnet assembly 213 is shown, where the magnet assembly 213 is radially segmented along the radial z-axis in both the smaller slot 207A and the larger slot 207B, as shown.

[0046] exist Figure 4A, as an example, the magnet assembly 213A corresponding to the smaller slot 207A and the magnet assembly 213B corresponding to the larger slot 207B each include three magnet segments. In the illustrated embodiment, the magnet assembly 213A includes two outer magnet segments 401 and 403 and one inner magnet segment 405 within the smaller slot 207A. Similarly, the magnet assembly 213B includes two outer magnet segments 407 and 409 and one inner magnet segment 411 within the larger slot 207B. In one embodiment as depicted with respect to the magnet assembly 213A, the cross-sections of the outer magnet segments 401 and 403 and the inner magnet segment 405 can all be rectangular in shape and have different cross-sectional dimensions. The cross-section of the inner magnet segment 405 is also rectangular. The outer magnet segments 401 and 403 can be different sizes, and the size of the inner magnet segment 405 is also not different. In one embodiment shown with respect to magnet assembly 213B, the cross-sections of outer magnet segments 407 and 409 and inner magnet segment 411 may be rectangular in shape. Both outer magnet segments 407 and 409 may be the same size and smaller than inner magnet segment 411.

[0047] exist Figure 4B , as an example, the magnet assembly 213A corresponding to the smaller slot 207A and the magnet assembly 213B corresponding to the larger slot 207B also include three magnet segments. In the illustrated embodiment, the magnet assembly 213A also includes two outer magnet segments 413 and 415 and one inner magnet segment 417 within the smaller slot 207A. Similarly, the magnet assembly 213B includes two outer magnet segments 419 and 421 and one inner magnet segment 423 within the larger slot 207B. In one embodiment as depicted with respect to the magnet assembly 213A, the cross-sections of the outer magnet segments 413 and 415 and the inner magnet segment 417 may all be trapezoidal in shape and have different cross-sectional sizes. The outer magnet segments 413 and 415 may be different sizes. In one embodiment shown with respect to the magnet assembly 213B, the cross-sections of the outer magnet segments 419 and 421 and the inner magnet segment 411 may all be trapezoidal in shape. The two outer magnet segments 419 and 421 may be the same size.

[0048] exist Figure 4C, as an example, the magnet assembly 213A corresponding to the smaller slot 207A and the magnet assembly 213B corresponding to the larger slot 207B also include three magnet segments. In the illustrated embodiment, the magnet assembly 213A also includes two outer magnet segments 425 and 427 and one inner magnet segment 429 within the smaller slot 207A. Similarly, the magnet assembly 213B includes two outer magnet segments 431 and 433 and one inner magnet segment 435 within the larger slot 207B. In one embodiment as depicted with respect to the magnet assembly 213A, the cross-sections of the outer magnet segments 425 and 427 can be triangular in shape, and the cross-section of the inner magnet segment 429 can be trapezoidal in shape. The outer magnet segments 425 and 427 can be the same size or different sizes as depicted. In one embodiment as depicted with respect to the magnet assembly 213B, the cross-sections of the outer magnet segments 431 and 433 can be triangular in shape, and the cross-section of the inner magnet segment 435 can be trapezoidal in shape. The two outer magnet segments 419 and 421 may be the same size.

[0049] For illustration purposes, Figure 5 Embodiments of magnet assemblies 213A and magnet assemblies 213B are depicted without a rotor core. Magnet assemblies 213A correspond to small slots in the rotor core, and magnet assemblies 213B correspond to large slots in the rotor core. Magnet assembly 213A corresponds to an embodiment of a magnet assembly that is axially segmented along an axial x-axis as depicted in FIG. B. Magnet assembly 213B corresponds to an embodiment of a magnet assembly that is radially segmented along a radial z-axis as depicted in FIG. In both of the embodiments of magnet assemblies 213A and 213B shown, the magnet segments are rectangular, but it should be understood that other shapes may be employed, such as approximately 1 / 4" and approximately 1 / 4" respectively. Figure 4B and 4C Trapezoid and triangle shown.

[0050] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to also include the plural forms, unless the context clearly indicates otherwise. It will be further understood that when used in this specification, the terms "include" and / or "comprise" specify the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or groups thereof.

[0051] All numerical values ​​herein are assumed to be modified by the term "about", whether explicitly stated or not. For the purposes of this disclosure, ranges may be expressed as from "about" one particular value to "about" another particular value. The term "about" generally refers to a range of values ​​that one skilled in the art would consider equivalent to the stated value, having the same function or result, or generally being reasonably within the manufacturing tolerance of the stated value. Similarly, the numerical values ​​set forth herein are provided as non-limiting examples and may be nominal values, it being understood that actual values ​​may differ from the nominal values ​​depending on the environment, design and manufacturing tolerances, age, and other factors.

[0052] When an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element, or there can be intervening elements. Conversely, when an element is referred to as being "directly on" another element, there are no intervening elements. Therefore, unless explicitly described as "directly," when describing a relationship between a first element and a second element in the above disclosure, the relationship can be a direct relationship between the first element and the second element without other intervening elements, but can also be an indirect relationship between the first element and the second element with one or more intervening elements (either spatially or functionally) present.

[0053] One or more steps within the method may be performed in a different order (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure may be implemented in and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the permutation of one or more embodiments with respect to each other is still within the scope of the present disclosure.

[0054] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0055] Unless otherwise indicated herein, all test standards are the most current standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0056] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. An interior permanent magnet motor, comprising: A rotor core having axially opposed ends and a plurality of slots, each slot extending through the rotor core between the axially opposed ends and containing a segmented magnet assembly including at least one magnet segment of a first magnetic material and at least one magnet segment of a second magnetic material.

2. The interior permanent magnet motor of claim 1, wherein: The segmented magnet assembly is segmented in a radial direction relative to an axis of rotation of the rotor core.

3. The interior permanent magnet motor of claim 2, wherein: The segmented magnet assembly includes radially outer magnet segments of a first magnetic material at radial ends of the segmented magnet assembly and at least one inner magnet segment of a second magnetic material radially between the radially outer magnet segments of the first magnetic material.

4. The interior permanent magnet motor of claim 3, wherein: The first magnetic material includes a heavy rare earth magnetic material, and the second magnetic material includes a non-heavy rare earth magnetic material.

5. The interior permanent magnet motor of claim 1 , wherein: The segmented magnet assembly is segmented in an axial direction relative to an axis of rotation of the rotor core.

6. The interior permanent magnet electric machine of claim 5, wherein: The segmented magnet assembly includes axially outer magnet segments of a first magnetic material at axial ends of the segmented magnet assembly and at least one inner magnet segment of a second magnetic material axially between the axially outer magnet segments of the first magnetic material.

7. The interior permanent magnet electric machine of claim 6, wherein: The first magnetic material includes a heavy rare earth magnetic material, and the second magnetic material includes a non-heavy rare earth magnetic material.

8. The interior permanent magnet electric machine of claim 1, wherein: The segmented magnet assembly is segmented in a circumferential direction relative to an axis of rotation of the rotor core.

9. The interior permanent magnet electric machine of claim 1, wherein: The segmented magnet assembly includes magnetic poles aligned in an axial direction relative to an axis of rotation of the rotor core.

10. The interior permanent magnet electric machine of claim 1, wherein: The segmented magnet assembly includes magnetic poles aligned in a radial direction relative to an axis of rotation of the rotor core.

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