Motor cooling

Abstract

The invention relates to motor cooling. Aspects of the subject disclosure relate to an electric motor having a cooling feature. The motor may provide cooling with fluid flow through channels containing magnets of the rotor. This provides the most beneficial cooling of the magnet so that the magnet can be selected without requiring too much adaptation to thermal conditions. The flow may be directed in different directions over the length of the rotor.

Description

Background Art

[0001] The present disclosure relates generally to the automotive, manufacturing, and industrial equipment fields. More specifically, the present disclosure relates to systems and methods for using flow along magnets to achieve motor cooling. In the context of electric vehicles, using flow along magnets to provide cooling can help optimize motor efficiency and vehicle energy usage, ultimately increasing the operating range of the vehicle battery. Summary of the Invention

[0002] In some embodiments, the present disclosure relates to a cooling device. A motor can be cooled using a fluid flow through channels containing magnets in a rotor. This provides optimal cooling for the magnets, allowing magnet selection without requiring significant adaptability to thermal conditions. The flow can be directed in different directions along the length of the rotor.

[0003] According to one or more aspects of the present disclosure, a rotor assembly for a motor may include a rotor shaft including an axial passage and a rotor core. The rotor core may be disposed about the rotor shaft and define a first magnet passage and a second magnet passage, each of the first magnet passage and the second magnet passage extending between opposite axial ends of the rotor core, each of the first magnet passage and the second magnet passage containing a magnet. The rotor shaft may define a first inlet passage and a second inlet passage, the first inlet passage extending through a first portion of a wall at a first end of the rotor shaft to provide fluid communication between the axial passage of the rotor shaft and the first magnet passage of the rotor core, and the second inlet passage extending through a second portion of the wall at a second end of the rotor shaft to provide fluid communication between the axial passage of the rotor shaft and the second magnet passage of the rotor core.

[0004] According to one or more aspects of the present disclosure, a motor may include a stator and a rotor. The stator may include stator coils configured to generate a rotating magnetic field. The rotor may include a rotor shaft including an axial channel, a rotor core, and magnets. The rotor core may be disposed about the rotor shaft and define a magnet channel extending between opposite axial ends of the rotor core. A magnet may be arranged in each magnet channel of the rotor core. The magnet may respond to the rotating magnetic field. The rotor shaft may define an inlet passage that passes through a wall of the rotor shaft to provide a fluid flow from the axial channel of the rotor shaft to the magnet channel of the rotor core when the rotor rotates.

[0005] According to one or more aspects of the present disclosure, a method for cooling a rotor assembly of a motor may include: providing a rotor assembly including a rotor shaft and a rotor core; providing a fluid to an axial channel of the rotor shaft; and directing the fluid to flow from the axial channel and through magnet channels of the rotor core, each magnet channel containing a magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Certain features of the subject technology are set forth in the appended claims.For purposes of illustration, however, several embodiments of the subject technology are set forth in the following figures.

[0007] Figure 1 A perspective cross-sectional view of an electric motor according to one or more implementations of the subject technology is shown.

[0008] Figure 2 A side cross-sectional view of a system for an electric motor is shown in accordance with one or more implementations of the subject technology.

[0009] Figure 3 A perspective cross-sectional view of a rotor assembly according to one or more implementations of the subject technology is shown.

[0010] Figure 4 An elevation view of a rotor core according to one or more implementations of the subject technology is shown.

[0011] Figure 5 A side view of a rotor assembly according to one or more implementations of the subject technology is shown.

[0012] Figure 6 A perspective view of a rotor assembly according to one or more implementations of the subject technology is shown.

[0013] Figure 7 A perspective view of an end plate according to one or more implementations of the subject technology is shown.

[0014] Figure 8 A perspective view of an end plate according to one or more implementations of the subject technology is shown.

[0015] Figure 9 An elevation view of a portion of a rotor assembly having an end plate is shown, according to one or more implementations of the subject technology.

[0016] Figure 10 An elevation view of a portion of a rotor assembly having an end plate is shown, according to one or more implementations of the subject technology.

[0017] Figure 11 A flow chart illustrating an exemplary process for directing cross-flow fluid in a motor in accordance with one or more implementations of the subject technology is shown.

[0018] Figure 12 A flow chart illustrating an exemplary process for removing heat from components of a motor in accordance with one or more implementations of the subject technology is shown. DETAILED DESCRIPTION

[0019] The specific embodiments set forth below are intended to describe various configurations of the subject technology and are not intended to represent the only configurations in which the subject technology can be practiced. The accompanying drawings are incorporated herein and constitute a part of the specific embodiments. The specific embodiments include specific details in order to provide a thorough understanding of the subject technology. However, the subject technology is not limited to the specific details set forth herein and can be practiced using one or more other specific implementations. In one or more specific implementations, well-known structures and components are shown in block diagram form to avoid confusion between the concepts of the subject technology.

[0020] The present specification as a whole relates to an electric motor comprising a rotor assembly having permanent magnets. One problem that can arise in motor cooling architectures is the concentration of motor losses near the outer surface of the rotor assembly. For example, motor losses result in the generation of heat, which can be extracted by stator and rotor cooling. Overheating of the magnets of the motor (e.g., in the rotor assembly) can cause the magnets to degrade over time. In some embodiments, the present disclosure is directed to achieving cooling of the magnets of the rotor assembly, for example, using a fluid flow directed by an end plate of the rotor assembly. Rather than indirectly cooling the magnets of the rotor assembly through the rotor core, the magnets can be disposed within a channel that receives a fluid flow for cooling the magnets via direct contact with a cooling fluid flow. By managing the thermal conditions of the magnets, the magnets can be protected from demagnetization. In some embodiments, such management can allow the selection of magnets with a lower threshold for resisting thermal conditions.

[0021] Therefore, in some embodiments, the present disclosure relates to a cooling device. A motor can be cooled using a fluid flow through channels containing magnets in a rotor assembly. This provides optimal cooling of the magnets, allowing magnets to be selected without requiring significant adaptability to thermal conditions. The flow can be directed in different directions along the length of the rotor.

[0022] refer to Figure 1 , a motor may include a stator and a rotor for providing a rotational output on a shaft. Figure 1 is a partial perspective view of the motor 4 having the stator 6 and the rotor assembly 10 .

[0023] In some embodiments, as Figure 1As shown, the motor 4 may include a generally cylindrical rotor shaft 12 concentrically surrounded by a cylindrical rotor assembly 10. As used herein, "cylindrical" and "annular" refer to structures having a generally circular inner cross-sectional shape and possibly a generally circular outer cross-sectional shape, although this outer cross-sectional shape may vary somewhat, having flat or irregular areas. The rotor shaft 12 and rotor assembly 10 are configured to rotate concentrically in unison about a common central axis 20, potentially at high revolutions per minute (RPM). The rotor assembly 10 may be made of electrical steel. The rotor shaft 12 may be made of steel and / or other possible metals or metal alloys.

[0024] The motor 4 may include a stator 6 including stator coils 8 configured to generate a rotating magnetic field. The rotating magnetic field may be generated by passing a multi-phase current through the stator coils 8. The stator coils 8 may form segments of windings distributed around the rotor assembly 10. For example, Figure 1 As shown, the stator coil 8 may be formed into segments, each extending in a direction generally parallel to the central axis 20 of the rotor assembly 10. The rotating magnetic field generated by the stator 6 may rotate about the central axis 20 of the rotor assembly 10. Neither the stator 6 nor the stator coil 8 need to move to generate the rotating magnetic field. For example, the coils may be operated with alternating current, with different segments having currents of different directions and / or magnitudes at any given moment. As the direction and / or magnitude of the current in each segment of the stator coil 8 varies over time, the magnetic field generated in its vicinity may vary accordingly. Thus, the resulting magnetic field may be characterized as rotating about the central axis 20 (e.g., having an alternating magnetic field direction extending circumferentially about the central axis 20). The rotating magnetic field may further extend through the rotor assembly 10, which may include permanent magnets 18. The rotating magnetic field generated by the stator 6 may magnetically interact with such components of the rotor assembly 10 to cause the rotor assembly 10 to rotate about the central axis 20.

[0025] The end windings (e.g., crown end windings and / or weld end windings) of the stator coils 8 of the stator 6 can be a conductive material such as copper or another suitable metal or material. The end windings of the stator coils 8 can protrude axially beyond the rotor assembly 10 and / or concentrically surround the rotor assembly 10. The end windings of the stator coils 8 are connected in parallel and / or in series with each other to form a set of windings having multi-phase terminals that are operatively connected to a drive, such as an inverter consisting of electrical switches.

[0026] The rotor shaft 12 and / or the rotor assembly 10 can rotate with a first bearing assembly 25 disposed at a first end of the rotor shaft 12 and a second bearing assembly 27 disposed at a second end of the rotor shaft 12. As such, when the rotor assembly 10 and / or the rotor shaft 12 responds to the rotating magnetic field generated by the stator 6, the rotor and / or the rotor shaft can rotate about the central axis 20. The rotor shaft 12 can accordingly provide a torque output.

[0027] Figure 2 1 shows a block diagram of a system 2 comprising a fluid reservoir 100, a pump 110, and a rotor assembly 10 of an electric motor. In some embodiments, as Figure 2 As shown, the rotor assembly 10 may include a rotor core 14 and one or more end plates (e.g., a first end plate 32 and a second end plate 34) at each of the opposing axial ends of the rotor core 14. In some embodiments, the rotor assembly 10 is an interior permanent magnet (IPM) rotor, which can inherently generate relatively high torque density and power density, for example, relative to an induction motor, due to a combination of magnetic torque and reluctance torque. In some embodiments, even though IPM rotor losses, core losses, and magnet losses may be relatively low compared to conventional induction motors, permanent magnet motors still experience rotor losses. For example, rotor losses can be converted into heat, which can affect both the remanence (Br) and coercive force (Hcj) of the permanent magnets, which can result in reduced torque and reduced demagnetization protection. Therefore, rotor cooling can enhance the operation of a motor (e.g., an IPM motor) for performance enhancement and achieve improved demagnetization performance in the motor.

[0028] To achieve cooling of the rotor assembly 10, a fluid (e.g., a liquid lubricant such as oil) is provided through the rotor assembly 10 via the first magnet passage 56 and the second magnet passage 58. The fluid is provided from a fluid reservoir 100 and directed by a pump 110 to the rotor shaft 12, such as through the shaft passage 22. The fluid reservoir may include and / or be fluidly coupled to one or more other conditioning components, such as a heat exchanger and / or a radiator.

[0029] The rotor shaft 12 may define a shaft passage 22, for example, along an axis of rotation of the rotor assembly 10. The rotor core 14 may be disposed about the rotor shaft 12. The rotor core 14 may include one or more layers and define one or more first magnet passages 56 and one or more second magnet passages 58, each extending between opposing axial ends of the rotor core 14. The rotor assembly 10 may further include one or more first end plates 32 and one or more second end plates 34 at each of the opposing axial ends of the rotor core 14.

[0030] The rotor shaft 12 may define one or more first inlet passages 42 extending through a first portion of the wall at a first end of the rotor shaft 12. It should be understood that the first inlet passage 42 may be further defined by one or more channels of the first end plate 32, such as facing the rotor core 14, as further described herein. In some embodiments, the first inlet passage 42 may be defined by and / or between the first end plate 32 and the rotor core 14. In some embodiments, the first inlet passage 42 may be completely defined within the first end plate 32. The one or more first inlet passages 42 may provide fluid communication between the shaft channel 22 of the rotor shaft 12 and the first magnet channel 56 of the rotor core 14. The first outlet passage 62 may be defined by one or more channels of the second end plate 34, such as facing the rotor core 14, as further described herein.

[0031] The rotor shaft 12 may further define one or more second inlet passages 44 extending through a second portion of the wall at a second end of the rotor shaft 12. It should be understood that the second inlet passage 44 may be further defined by, for example, one or more channels of the second end plate 34 facing the rotor core 14, as further described herein. In some embodiments, the second inlet passage 44 may be defined by and / or between the second end plate 34 and the rotor core 14. In some embodiments, the second inlet passage 44 may be completely defined within the second end plate 34. The one or more second inlet passages 44 may provide fluid communication between the shaft channel 22 of the rotor shaft 12 and the second magnet channel 58 of the rotor core 14. The second outlet passage 64 may be defined by, for example, one or more channels of the first end plate 32 facing the rotor core 14, as further described herein.

[0032] When relatively cool oil enters shaft passage 22 (e.g., the shaft passage of hollow rotor shaft 12, as shown), the fluid then flows to first and second inlet passages 42, 44, which open into shaft passage 22 near respective opposite axial ends of rotor core 14. Each of first and second inlet passages 42, 44 may include a respective set of passages arranged azimuthally about the axis of rotation (e.g., in an equally spaced pattern or other suitable arrangement). The fluid flows approximately axially in first magnet passage 56 in a first direction, and approximately axially in second magnet passage 58 in a second direction opposite the first direction, thereby forming an axial crossflow arrangement. As the fluid flows through first and second magnet passages 56, 58, the fluid absorbs heat generated by losses in rotor assembly 10 through contact between the fluid, magnets (not shown) in the rotor assembly, and the walls of rotor core 14 (e.g., which may include electrical steel). With the first magnet channel 56 and the second magnet channel 58 forming a cross-flow arrangement, the rotor assembly 10 can exhibit a relatively more uniform temperature gradient (e.g., a reduced axial temperature gradient). After absorbing heat generated by losses in the rotor assembly 10, the fluid flows out of the first outlet passage 62 and the second outlet passage 64, for example, along the first end plate 32 and the second end plate 34 facing the corresponding sides of the rotor core 14. The fluid travels radially outward along the first outlet passage 62 and the second outlet passage 64 (e.g., due to centrifugal force). This flow can optionally include cooling and / or other thermal management of the stator (e.g., at the end windings). The fluid can flow, drip, or otherwise return to the reservoir 100 to be recirculated in the fluid system (e.g., by operation of the pump 110 to repeat the heat transfer in a continuous flow).

[0033] In the illustrative example, the electric motor of system 2 may correspond to an electric motor having improved performance due, at least in part, to efficient heat extraction using fewer components. To illustrate, a rotor, such as rotor assembly 10, may exhibit a uniform thermal gradient as a fluid extracts heat from the core of rotor assembly 10. In some embodiments, rotor core 14 may include a plurality of laminates and first and second end plates 32, 34 that may have a common design, thereby resulting in relatively low component cost and fewer components or component types.

[0034] Now refer to Figure 3 and Figure 4 , the magnet channels can be arranged to provide flow in one or more of a variety of directions. Figure 3 As shown, a rotor core 14 may be disposed about the rotor shaft 12 .

[0035] In some embodiments, the rotor assembly 10 may define one or more first inlet passages 42 that pass through a first portion of the wall of the rotor shaft 12 and / or between the rotor core 14 and the first end plate 32. The first inlet passages 42 of the rotor core 14 are shown at radially opposite sides of the rotor shaft 12. It should be understood that any one or more of the first inlet passages 42 may be positioned at any circumferential location on the first side of the rotor shaft 12. A second inlet passage (not shown) may be at a different circumferential location along the rotor core 14.

[0036] In some embodiments, the rotor assembly 10 may define one or more first inlet passages 42 that pass through a first portion of the wall of the rotor shaft 12 and / or between the rotor core 14 and the first end plate 32. The first magnet passages 56 of the rotor core 14 are shown on diametrically opposite sides of the rotor shaft 12. It should be understood that any one or more of the first magnet passages 56 may be positioned at any circumferential location within the rotor core 14. A second magnet passage (not shown) may be at a different circumferential location within the rotor core 14.

[0037] In some embodiments, the rotor assembly 10 may define one or more first outlet passages 62 passing between the rotor core 14 and the second end plate 34. In some embodiments, the first outlet passage 62 and / or the second outlet passage 64 may be defined by and / or between the rotor core 14 and the first end plate 32 or the rotor core 14 and the second end plate 34. The first outlet passages 62 are shown on radially opposite sides of the rotor shaft 12 and on axially opposite sides of the rotor core 14. It should be understood that any one or more of the first outlet passages 62 may be positioned at any circumferential position relative to the rotor shaft 12. A second outlet passage (not shown) may be located at a different circumferential position along the rotor core 14.

[0038] Figure 4 An end view of an exemplary rotor core 14 having a first magnet channel 56 and a second magnet channel 58 according to some embodiments of the present disclosure is shown. The first magnet channel 56 and the second magnet channel 58 can be arranged to azimuthally surround a rotor shaft (not shown) that fits within the rotor core 14. For example, Figure 4As shown, the rotor core 14 includes 16 channels (e.g., eight first magnet channels 56 and eight second magnet channels 58), wherein each set of adjacent first magnet channels 56 and second magnet channels 58 forms a pair, with each corresponding pair being 45 degrees apart in azimuth. Each of the first magnet channels 56 and second magnet channels 58 may include one or more magnets 18 positioned therein. For example, a magnet 18 may occupy a portion of a corresponding magnet channel in the first magnet channels 56 and second magnet channels 58. The magnet 18 may be fixed in place, for example, based on the geometry of the corresponding magnet channel in the first magnet channels 56 and second magnet channels 58 and / or magnetic coupling with the body 16 of the rotor core 14. The magnet 18 may occupy space such that portions of the first magnet channels 56 and second magnet channels 58 remain open to facilitate fluid flow therethrough. In this way, the first magnet channels 56 and second magnet channels 58 may allow fluid to flow directly against the magnets 18 to cool them. Space for flow may be provided on either side of each given magnet 18, including at its long ends.

[0039] Now refer to Figure 5 , the magnet channel of the rotor may extend in one or more directions. Figure 5 As shown, the body of the rotor assembly 10 may include a plurality of laminates (e.g., steel) formed into layers 24 having first and second magnet channels 56, 58. While four layers 24 are shown, it should be understood that any number of layers 24 may be provided. Each of the layers 24 may be circumferentially offset relative to adjacent layers of the other layers 24. Such offsetting may provide for flow in a non-axial path through each of the first and second magnet channels 56, 58. For example, the first and second magnet channels 56, 58 may extend along a linear or nonlinear path that curves partially around the central axis of the rotor assembly 10 rather than parallel to the central axis. This may result in an inlet passageway on one side of each of the first and second magnet channels 56, 58 (e.g., at the first end plate 32) being circumferentially offset relative to an outlet passageway on the opposite side of the corresponding one of the first and second magnet channels 56, 58 (e.g., at the second end plate 34). In this manner, the first and second magnet channels 56, 58 may generally form a spiral path. Such a spiral path may facilitate fluid travel therethrough as the rotor assembly 10 rotates. It should be appreciated that the first and second magnet channels 56, 58 may extend in other manners, such as parallel to the central axis of the rotor assembly 10 and / or parallel to each other.

[0040] Now refer to Figures 6 to 10, the rotor assembly may include end plates to facilitate the flow of fluid. The rotor assembly 10 may include a rotor shaft 12, a first end plate 32 and a second end plate 34, and a rotor core 14. The rotor shaft 12 includes an axial passage 22 that leads to a first inlet passage 42 formed at least in part by the first end plate 32. The second end plate 34 may at least partially form a second inlet passage 44 (not shown). The first end plate 32 and the second end plate 34 may be identical to each other, but locked in orientation relative to each other (e.g., approximately 45 degrees) such that the first inlet passage 42 is azimuthally aligned with the corresponding first outlet passage 62 and the second outlet passage 64 is azimuthally aligned with the corresponding inlet passage 44 (not shown). It should be understood that the circumferential arrangement of the first end plate 32 and the second end plate 34 may accommodate any helical winding of the first magnet passage 56 and the second magnet passage 58, such as Figure 5 shown.

[0041] A fluid (such as oil) enters the first inlet passage 42 and fills the first end plate 32 (e.g., the cavity indicated by the first inlet passage 42 of the first end plate 32). Similarly, the fluid enters the second inlet passage (not shown) and fills the second end plate 34. After entering the first inlet passage 42 and the second inlet passage, the fluid travels axially through the rotor core 14 (e.g., the rotor core 14 may be formed of electrical steel). For example, the rotor core 14 includes first and second magnet channels corresponding to the first and second outlet passages 62 and 64. As the fluid flows through the first and second magnet channels, heat (e.g., caused by rotor losses) is absorbed by the fluid through contact between the fluid and the rotor core 14 and / or the magnets therein.

[0042] In some embodiments, the first inlet passage 42 (e.g., cavity) of the first end plate 32 coincides with a first magnet channel (not shown) in the rotor core 14 (e.g., rotor lamination stack), and similarly, the second inlet passage 44 (not shown) of the second end plate 34 coincides with a second magnet channel 58 in the rotor core 14 (e.g., rotor lamination stack). This arrangement allows for cross-flow of fluid to achieve rotor heat dissipation with a uniform temperature gradient within the rotor assembly 10. After absorbing heat generated by rotor losses, the fluid exits the first and second end plates 32, 34 via the first and second outlet passages 62, 64 and then travels radially outward, cooling the stator end windings at each axial end (e.g., the lead side and weld side of a hairpin motor). The fluid extracts heat symmetrically from the end windings, balancing the end windings on both axial ends of the stator. In another illustrative example, using a common first and second end plates 32, 34 allows for lower component costs and fewer parts. Furthermore, the symmetrical oil flow to the two end windings balances the cooling at the ends of the stator.

[0043] In some embodiments, each of the first inlet passage 42 and / or the second inlet passage 44 can extend and be fluidly connected to one or more magnet channels in the first magnet channel 56 and / or the second magnet channel 58. In this way, fluid can be directed from any given one or more of the first inlet passage 42 and the second inlet passage 44 to multiple magnet channels in the first magnet channel 56 and the second magnet channel 58.

[0044] In some embodiments, each of the first outlet passage 62 and / or the second outlet passage 64 can extend and be fluidly connected to one or more magnet channels in the first magnet channel 56 and / or the second magnet channel 58. In this way, fluid can be directed from multiple magnet channels in the first magnet channel 56 and the second magnet channel 58 to any given one or more outlet passages in the first outlet passage 62 and the second outlet passage 64.

[0045] Figure 7 A perspective view of an exemplary first end plate 32 having a first inlet passage 42 and a second inlet passage 64 is shown according to some embodiments of the present disclosure. For illustration, the first end plate 32 may be Figures 2 to 3 and Figures 5 and 6 The first end plate 32 and the second end plate 34 are identical or similar, but need not be identical or similar. Figure 7 As shown, the first end plate 32 may include four first inlet passages 42 indicated as cavities or recesses. For example, a fluid (such as oil) is directed from the shaft passage of the rotor shaft into the first inlet passages 42 and then flows from the first inlet passages 42 into the magnet passages that are directed longitudinally (e.g., axially or helically) and out of the outlet passages of another end plate (e.g., the same as the first end plate 32 but locked 45 degrees in orientation). In some embodiments, the first inlet passage 42 may branch into multiple paths (see Figure 7 ), the plurality of paths may extend to each of the plurality of magnet channels and / or through portions of such magnet channels. The first end plate 32 may also include a second outlet passage 64 through which fluid flows from a recess of the other end plate through the magnet channels of the rotor (e.g., Figures 2 to 5 The magnets are then fed through the second outlet passage 64. The second outlet passage 64 may include closed channels and / or recesses to expose corresponding magnet channels. In the illustrative example, the rotor may include two end plates (e.g., a front plate and a rear plate), each identical to the first end plate 32, and locked relative to each other to form a cross-flow pattern.

[0046] Figure 8 A perspective view of another exemplary first end plate 32 having a first inlet passage 42 and a second inlet passage 64 according to some embodiments of the present disclosure is shown. For illustration, the first end plate 32 may be Figures 2 to 3and Figures 5 and 6 The first end plate 32 and the second end plate 34 are identical or similar, but need not be identical or similar. Figure 8 As shown, the first end plate 32 may include a ring 36 for collecting fluid. The ring 36 may be continuous around a central region (e.g., for receiving the rotor shaft) and may be fluidically connected to each first inlet passage 42. The first end plate 32 may include one or more recesses 38 for collecting additional fluid. The recesses 38 may be discrete and separated from each other while being fluidically connected to the ring 36. The collection of fluid in the ring 36 and / or recesses 38 may help direct the fluid into the first inlet passages 42, particularly when the rotor assembly rotates about the axis and centrifugal forces push the fluid radially outward. The first end plate 32 may further include eight first inlet passages 42, indicated as channels. For example, fluid (such as oil) is directed from the shaft passage of the rotor shaft into the first inlet passages 42 and then flows from the first inlet passages 42 into the magnet passages that are directed longitudinally (e.g., axially or helically) and out of the outlet passages of another end plate (e.g., the same as the first end plate 32 but oriented 45 degrees). The first inlet passage 42 may have a curved shape that helps distribute the fluid as the rotor assembly rotates. For example, the first inlet passage 42 may extend from the ring 36 in a radially outward direction (e.g., orthogonal to the rotor axis of rotation) to facilitate movement of the fluid from the ring 36. The curved path may further cause the flow to extend into and / or through one or more magnet channels and / or portions thereof. In some embodiments, the first inlet passage 42 may branch into multiple paths (see Figure 7 ), the plurality of paths may extend to each of the plurality of magnet channels and / or through portions of such magnet channels. The first end plate 32 may also include a second outlet passage 64 through which fluid flows from a recess of the other end plate through the magnet channels of the rotor (e.g., Figures 2 to 5 The magnets are then fed through the second outlet passage 64. The second outlet passage 64 may include closed channels and / or recesses to expose corresponding magnet channels. In the illustrative example, the rotor may include two end plates (e.g., a front plate and a rear plate), each identical to the first end plate 32, and locked relative to each other to form a cross-flow pattern.

[0047] Figure 8 FIG. 1 shows a front view of a portion of an exemplary first end plate 32 having second outlet passages 64, each connected to a second magnet channel 58, according to some embodiments of the present disclosure. For illustration, the first end plate 32 may be connected to a second magnet channel 58. Figures 2 to 3 and Figures 5 to 8 The first end plate 32 and the second end plate 34 are identical or similar, but need not be identical or similar. Figure 8 As shown, the first end plate 32 may include a second outlet passage 64 through which fluid flows from a recess in the other end plate through the second magnet channel 58 of the rotor (e.g., as shown in FIG. Figures 2 to 5 The second outlet passage 64 may include a portion that matches the contour (e.g., edge or wall) of the second magnet channel 58. Thus, the flow from the second magnet channel 58 can be smoothly guided to the second outlet passage 64.

[0048] Figure 9 1 shows a front view of a portion of another exemplary first end plate 32 having second outlet passages 64, each connected to a second magnet channel 58, according to some embodiments of the present disclosure. Figures 2 to 3 and Figures 5 to 8 The first end plate 32 and the second end plate 34 are identical or similar, but need not be identical or similar. Figure 9 As shown, the first end plate 32 may include a second outlet passage 64 through which fluid flows from a recess in the other end plate through the second magnet channel 58 of the rotor (e.g., as shown in FIG. Figures 2 to 5 18 and / or after passing through the magnet 18, exits through the second outlet passage. The second outlet passage 64 may include a shape that is different from and / or larger than the shape of the second magnet passage 58. In some embodiments, the second outlet passage 64 may include a taper, chamfer, bevel, fillet, and / or other shape to form a transition. Thus, the flow from the second magnet passage 58 can directly and freely pass through the second outlet passage 64.

[0049] Figure 11 A flow chart illustrating an exemplary process 1100 for directing a cross-flow fluid in a motor according to one or more implementations of the subject technology is shown. Figures 1 to 10 Process 1100 is described with reference to components of a system, motor, rotor, and / or assembly. However, process 1100 is not limited to Figures 1 to 10 1100. The present invention relates to a system, motor, rotor and / or component of the present invention, and one or more blocks (or operations) of process 1100 may be performed by one or more other components of other suitable devices, equipment or systems. Further for the purpose of explanation, some blocks in the blocks of process 1100 are described herein as occurring continuously or linearly. However, multiple blocks of process 1100 may occur in parallel. In addition, the blocks of process 1100 need not be performed in the order shown, and / or one or more blocks of process 1100 need not be performed and / or may be replaced by other operations.

[0050] Block 1102 includes providing a fluid to the interior of the rotor shaft. Block 1102 may include pumping the fluid to an increased pressure to force the fluid into the interior of the rotor shaft (eg, a hollow interior region such as a Figure 1 and Figure 2In some embodiments, block 1102 may include filtering the fluid, regulating the pressure of the fluid, controlling one or more flow paths of the fluid, controlling the flow rate of the fluid, controlling the temperature of the fluid (e.g., using a radiator or other heat exchanger), or a combination thereof. In an illustrative example, block 1102 may include providing pressurized oil to the interior of the rotor shaft based on the flow of the oil.

[0051] Block 1104 includes directing the fluid in the first path from the first inlet passage to the first magnet passage in a first direction. In some embodiments, the fluid within the interior of the rotor shaft provided at block 1102 is caused to flow in the first path (e.g., the fluid flows in a reduced pressure path) based on the pressure field in the first path. For example, the first path may open into the interior of the rotor shaft, such that the fluid can flow from the interior of the rotor shaft through the first path. The first path may include, for example, a first inlet passage that interfaces with the interior of the rotor shaft (e.g., is in fluid communication with or otherwise opens into the interior of the rotor shaft), one or more first magnet passages, and a first outlet passage through which the fluid exits.

[0052] Block 1106 includes directing the fluid from the first magnet channel to the first end winding. In some embodiments, after the fluid flows through the first magnet channel, the fluid flows radially outward, thereby impinging on the first end winding (e.g., the first end winding of the stator corresponding to the rotor) in a spray or other manner. The fluid can flow to the first end winding under the influence of centrifugal acceleration, pressure, gravity, or a combination thereof. It should be understood that block 1106 can optionally be omitted, such that the flow does not need to be directed to the first end winding.

[0053] Block 1108 includes directing the fluid in the second path from the second inlet passage to the second magnet passage in a second direction. In some embodiments, the fluid within the interior of the rotor shaft provided at block 1102 is caused to flow in the second path (e.g., the fluid flows in a reduced pressure path) based on the pressure field in the second path. For example, the second path may open into the interior of the rotor shaft, allowing the fluid to flow through the second path from the interior of the rotor shaft. The second path may include, for example, a second inlet passage that interfaces with the interior of the rotor shaft (e.g., is in fluid communication with or otherwise opens into the interior of the rotor shaft), one or more second magnet passages, and a second outlet passage through which the fluid exits.

[0054] Block 1110 includes directing the fluid from the second magnet channel to the second end winding. In some embodiments, after the fluid flows through the second magnet channel, the fluid flows radially outward, thereby impinging on the second end winding (e.g., the second end winding of the stator corresponding to the rotor) in a spray or other manner. The fluid can flow to the second end winding under the influence of centrifugal acceleration, pressure, gravity, or a combination thereof. It should be understood that block 1110 can optionally be omitted, so that the flow does not need to be directed to the second end winding.

[0055] It should be understood that blocks 1108 and / or 1110 may be omitted or modified, such as where flow is in a single direction (e.g., axial direction) within the magnet channel. Figure 11 One or more of the described paths together provide other paths having corresponding directions.

[0056] Block 1112 includes collecting the fluid and recirculating it. For example, after the fluid flows through or otherwise passes through the first and second end windings, the fluid is collected and recirculated. Block 1112 may include collecting the fluid in a basin, or in an oil sump or reservoir area, and draining the fluid by suction (e.g., via fluid pressure) or gravity to a filter, a pump, a radiator, a plenum, any other suitable component, or any combination thereof. In some embodiments, for example, the fluid (e.g., oil) is directed through the first and second end windings and then collected in a basin to be recirculated to the interior of the rotor shaft (e.g., after heat is removed via a radiator or heat exchanger).

[0057] Figure 12 A flow chart illustrating an exemplary process 1200 for removing heat from components of a motor according to one or more implementations of the subject technology is shown. Figures 1 to 10 Process 1200 is described with reference to components of a system, motor, rotor, and / or assembly. However, process 1200 is not limited to Figures 1 to 10 In another example, the process 1200 or any of its blocks may be executed by other suitable devices, apparatuses, or one or more other components of the system. Figure 11 1100. Further, for purposes of explanation, some of the blocks in process 1200 are described herein as occurring serially or linearly. However, multiple blocks of process 1200 may occur in parallel. Furthermore, the blocks of process 1200 need not be performed in the order shown, and / or one or more blocks of process 1200 need not be performed and / or may be replaced by other operations.

[0058] Block 1202 includes providing current to windings of an electric motor to apply torque to a rotor shaft relative to a stator. In some embodiments, block 1202 includes generating control signals for power electronics to apply current to phases of the electric motor to generate torque on the rotor and cause the rotor to rotate relative to the stator. For example, in some embodiments, the rotor may include permanent magnets and the stator may include phase windings (including end windings) and stator teeth.

[0059] Block 1204 includes generating heat in the bearings, windings, and rotor components. For example, as the rotor rotates about its axis, heat may be generated in the rotor (e.g., due to losses), in the bearings (e.g., due to friction), and in the end windings (e.g., due to losses, such as ohmic losses). In some embodiments, the amount of heat generated in the electric motor depends on the current profile applied at block 1202. For example, as more current is applied, for a longer duration of current, or both, particularly at higher rotational speeds (e.g., higher excitation frequencies), more heat may be generated in the electric motor and its components.

[0060] Block 1206 includes directing fluid in one or more flow paths through magnets in the rotor to receive heat. In some embodiments, block 1206 includes directing fluid in a first flow path and a second flow path, where the first flow path and the second flow path may directly contact the one or more magnets. In some embodiments, block 1206 includes providing pressurized fluid to inlet passages of the rotor, thereby causing the fluid to flow under pressure through the flow paths to the corresponding outlet passages.

[0061] Block 1208 includes directing the fluid radially outward toward the end windings. In some embodiments, the fluid flows through the flow path of block 1206 and then exits a corresponding outlet passage at each axial end of the rotor. The fluid then flows radially outward along the end plates of the rotor at block 1208 to impinge on or otherwise flow through the radially outwardly disposed end windings of the rotor. At block 1208, the fluid may flow under the influence of centrifugal force, gravity, pressure, or a combination thereof. For example, in some embodiments, as the rotor rotates, the fluid flows radially outward and impinges upon the end windings, thereby cooling the windings through convective heat transfer from the interface layer.

[0062] Block 1210 involves transferring heat to a circulating fluid. The fluid receives heat from the rotor (e.g., magnets) and end windings via convection and transfers heat (e.g., thermal energy stored in the fluid) away from the rotor. For example, the fluid can be directed to a radiator or other heat exchanger to remove the heat transferred at block 1210 and then recirculated to the rotor for continued cooling.

[0063] In an illustrative example, an illustrative process (e.g., process 1100, process 1200, or a combination thereof) may include providing coolant to a plurality of magnet channels extending axially through a rotor assembly and configured to provide a cross flow of coolant (e.g., at block 1102 and / or block 1206). The process may also include generating heat in the rotor assembly (e.g., at block 1204) and transferring the heat from the plurality of magnet channels to the coolant (e.g., at blocks 1206 and 1210, or during blocks 1104 and 1108, or a combination thereof).

[0064] In another illustrative example, the plurality of magnet channels may include a first magnet channel and a second magnet channel. The first magnet channel may extend axially in a first direction to a first outlet passage, and the second magnet channel may extend axially in a second direction opposite to the first direction to a second outlet passage. Providing coolant to the plurality of magnet channels may include, for example, providing coolant to the first magnet channel coupled to the first inlet passage and providing coolant to the second magnet channel coupled to the second inlet passage (e.g., at blocks 1104 and 1108, block 1206, or a combination thereof).

[0065] In another illustrative example, a rotor assembly may include a first end plate disposed at a first axial position and including a first outlet passage, and a second end plate disposed at a second axial position and including a second outlet passage. An illustrative process (e.g., process 1100, process 1200, or a combination thereof) may include causing coolant to flow radially outward along the first end plate to the first end winding (e.g., at block 1106 or block 1208), causing coolant to flow radially outward along the second end plate to the second end winding (e.g., at block 1110 or block 1208), and transferring heat from the first end winding and from the second end winding to the coolant.

[0066] Unless otherwise specified, an element mentioned in the singular is not intended to mean one and only one, but rather one or more. For example, "a" module may refer to one or more modules. Without further constraints, an element beginning with "a," "an," "the," or "said" does not exclude the presence of additional identical elements.

[0067] Headings and subheadings, if any, are used for convenience only and do not limit the invention. The word exemplary is used to mean serving as an example or illustration. To the extent that the terms "including" or "having" and the like are used, such terms are intended to be inclusive in a manner similar to the term "comprising," as understood when "comprising" is used as a transitional term in a claim. Relational terms such as first and second, etc., may be used to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0068] Phrases such as an aspect, this aspect, another aspect, some aspects, one or more aspects, a specific implementation, this specific implementation, another specific implementation, some specific implementations, one or more specific implementations, an embodiment, this embodiment, another embodiment, some embodiments, one or more embodiments, a configuration, this configuration, another configuration, some configurations, one or more configurations, subject technology, this disclosure, the present disclosure, and other variations thereof are for convenience and do not imply that the disclosure associated with such phrases is essential to the subject technology or that such disclosure applies to all configurations of the subject technology. The disclosure associated with such phrases may apply to all configurations or one or more configurations. The disclosure associated with such phrases may provide one or more examples. Phrases such as an aspect or some aspects may refer to one or more aspects, and vice versa, and this applies similarly to the other aforementioned phrases.

[0069] The phrase "at least one of" following a list of items, with the terms "and" or "or" used to separate any of those items, modifies the list as a whole, not each of the constituent items of the list. The phrase "at least one of" does not require selection of at least one item; rather, the phrase allows for a meaning that includes at least one of any of those items, and / or at least one of any combination of those items, and / or at least one of each of those items. By way of example, each of the phrases "at least one of A, B, and C" or "at least one of A, B, or C" means only A, only B, or only C; any combination of A, B, and C; and / or at least one of each of A, B, and C.

[0070] It should be understood that the specific order or level of the disclosed steps, operations or processes are illustrations of exemplary methods. Unless otherwise clearly stated, it should be understood that the specific order or level of steps, operations or processes can be performed in different orders. Some of the steps, operations or processes can be performed simultaneously. The attached method claims (if any) present the elements of various steps, operations or processes in a sample order and are not meant to be limited to the specific order or level presented. These can be performed serially, linearly, in parallel or in different orders. It should be understood that the described instructions, operations and systems can usually be integrated together in a single software / hardware product or encapsulated in multiple software / hardware products.

[0071] Terms such as top, bottom, front, back, side, horizontal, vertical, etc. refer to an arbitrary reference frame other than the ordinary gravitational reference frame. Thus, such terms can extend upward, downward, diagonally, or horizontally in a gravitational reference frame.

[0072] The present disclosure is provided to enable anyone skilled in the art to practice the various aspects described herein. In some instances, well-known structures and components are shown in block diagram form to avoid confusion about the various concepts of the subject technology. The present disclosure provides various examples of the subject technology, and the subject technology is not limited to these examples. Various modifications to these aspects will be readily apparent to those skilled in the art, and the principles described herein may be applied to other aspects.

[0073] All structural and functional equivalents of the various elements of the various aspects described throughout this disclosure are known or will later become known to those of ordinary skill in the art, and these equivalents are expressly incorporated herein by reference and are intended to be included in the claims. In addition, nothing disclosed herein is intended to serve the public, regardless of whether such disclosure is explicitly stated in the claims. No claim element should be interpreted under the provisions of 35 U.S.C. § 112 (f) unless the phrase "means for..." is used to expressly state the element, or in the case of a method claim, the phrase "step for..." is used to state the element.

[0074] Those skilled in the art will appreciate that the various exemplary blocks, modules, elements, parts, methods and algorithms described herein can be implemented as hardware, electronic hardware, computer software or a combination thereof. To illustrate this interchangeability of hardware and software, various exemplary blocks, modules, elements, parts, methods and algorithms have been generally described above in terms of their functionality. Whether this functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the entire system. Those skilled in the art can implement the described functionality in different ways for each specific application. Various components and blocks can be arranged differently (e.g., arranged in different orders or divided in different ways), all of which do not depart from the scope of this subject technology.

[0075] The titles, figure descriptions, abstracts, and drawings are hereby incorporated into this disclosure and are provided as illustrative examples of the disclosure and not as limiting descriptions. This document is filed with the understanding that they will not be used to limit the scope or meaning of the claims. Furthermore, in the detailed description, it can be seen that for the purpose of simplifying the disclosure, the description provides illustrative examples and that various features are grouped together in various implementations. This method of disclosure should not be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, as reflected in the claims, the inventive subject matter lies in less than all the features of a single disclosed configuration or operation. The claims are hereby incorporated into the detailed description, with each claim standing on its own as separately claimed subject matter.

[0076] The claims are not intended to be limited to the aspects described herein, but should be accorded the full scope consistent with the language of the claims and encompassing all legal equivalents. Nevertheless, none of the claims is intended to encompass subject matter that fails to meet the requirements of applicable patent law, nor should they be interpreted in such a manner.

Claims

1. A rotor assembly for a motor, the rotor assembly comprising: a rotor shaft including a shaft passage; and a rotor core disposed about the rotor shaft and defining a first magnet channel and a second magnet channel, each of the first magnet channel and the second magnet channel extending between opposite axial ends of the rotor core, each of the first magnet channel and the second magnet channel containing a magnet, wherein the rotor shaft defines: a first inlet passageway extending through a first portion of a wall at a first end of the rotor shaft to provide fluid communication between the shaft passageway of the rotor shaft and the first magnet passageway of the rotor core; and A second inlet passage extends through a second portion of the wall at a second end of the rotor shaft to provide fluid communication between the shaft passage of the rotor shaft and the second magnet passage of the rotor core.

2. The rotor assembly according to claim 1, further comprising: a first end plate coupled to a first end of the rotor core, the first end plate at least partially defining the first passage; and A second end plate is coupled to a second end portion of the rotor core, the second end plate at least partially defining the second passageway. 3 . The rotor assembly of claim 1 , wherein the first and second inlet passages are circumferentially offset relative to each other.

4. The rotor assembly of claim 1 , wherein each of the first and second inlet passages extends transverse to a rotor axis, the rotor axis extending through the shaft passage and the rotor assembly being configured to rotate about the rotor axis. 5 . The rotor assembly of claim 1 , wherein each of the first inlet passage and the second inlet passage form a tortuous path.

6. The rotor assembly of claim 1 , wherein: The first magnet channels are arranged in pairs, the pairs of first magnet channels being circumferentially adjacent to each other; and The second magnet channels are arranged in pairs, and the pairs of second magnet channels are circumferentially adjacent to each other.

7. The rotor assembly of claim 1 , wherein the rotor core is formed of a plurality of layers arranged along a rotor axis, each of the plurality of layers being circumferentially offset relative to an adjacent other of the plurality of layers such that the first magnet channel and the second magnet channel are wound around the rotor axis between the opposite axial ends of the rotor core.

8. A motor, comprising: a stator comprising stator coils configured to generate a rotating magnetic field; and A rotor, comprising: a rotor shaft, the rotor shaft comprising a shaft passage; a rotor core disposed about the rotor shaft and defining a magnet passage extending between opposing axial ends of the rotor core; and a magnet disposed in each of the magnet channels of the rotor core, the magnet being responsive to the rotating magnetic field, wherein the rotor shaft defines an inlet passageway through a wall of the rotor shaft to provide fluid flow from the shaft channel of the rotor shaft to the magnet channels of the rotor core when the rotor rotates.

9. The motor of claim 8, wherein the magnet channels provide space for the fluid flow on each of opposing sides of each of the magnets.

10. The motor of claim 8, wherein the rotor core is formed of a plurality of layers arranged along a rotor axis, each of the plurality of layers being circumferentially offset relative to an adjacent other of the plurality of layers such that the magnet channel is wound around the rotor axis between the opposite axial ends of the rotor core. 11 . The motor of claim 8 , wherein the rotor further comprises end plates coupled to opposite ends of the rotor core, the end plates at least partially defining the inlet passage.

12. The motor of claim 11, the end plate at least partially defining outlet passages, each of the outlet passages axially opposed to a corresponding one of the inlet passages.

13. The motor of claim 8, wherein the magnet channel comprises: a first magnet channel connected to the shaft channel at a first end of the rotor; and A second magnet channel is connected to the shaft channel at a second end of the rotor.

14. The motor of claim 8, further comprising a pump configured to receive the fluid from the magnet passage and direct the fluid to the shaft passage.

15. A method for cooling a rotor assembly of a motor, the method comprising: providing the rotor assembly comprising a rotor shaft and a rotor core; providing fluid to the shaft passage of the rotor shaft; as well as The fluid is directed to flow from the shaft passage and through magnet passages of the rotor core, each of the magnet passages containing a magnet.

16. The method of claim 15, wherein the fluid flows past each magnet within the magnet channel.

17. The method of claim 15, wherein the fluid flows through two of the magnet channels in opposite directions.

18. The method of claim 15, wherein providing the fluid to the shaft passage comprises: A pump is operated to receive the fluid from the rotor core and direct the fluid to the shaft passage.

19. The method of claim 15, wherein directing the fluid comprises: directing the fluid from the shaft passage through a wall of the rotor shaft; directing the fluid to the magnet channel via an inlet passage between the rotor core and an end plate of the rotor assembly; directing the fluid through each magnet; as well as The fluid is directed away from the magnet channel via an outlet passage between the rotor core and the end plate of the rotor assembly.

20. The method of claim 15, wherein directing the fluid flow comprises: The rotor assembly is caused to rotate.

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