Planetary coaxial power assembly and electric vehicle

Abstract

The application provides a planetary coaxial power assembly and an electric vehicle, and relates to the technical field of electric vehicles. The planetary reducer of the planetary coaxial power assembly is used for receiving power output by a driving motor and driving wheels of the electric vehicle through a transmission shaft. The motor shaft of the driving motor passes through the central hole of the rotor core of the motor rotor. The transmission shaft passes through the motor shaft of the driving motor. The two ends of the transmission shaft are respectively used for driving connection with the planetary reducer and the wheels. The rotor core comprises a plurality of magnetic isolation bridges. The plurality of magnetic isolation bridges are distributed around the central hole. Each magnetic isolation bridge is used for separating two magnetic steel grooves in a V-shaped magnetic steel groove. The rotor core further comprises a plurality of groups of first magnetic isolation grooves. Each group of first magnetic isolation grooves comprises a plurality of first magnetic isolation grooves. The plurality of first magnetic isolation grooves in each group of first magnetic isolation grooves are distributed in the magnetic isolation bridges along the radial direction of the driving motor, so that the mechanical strength of the rotor core is relatively high, the magnetic leakage is reduced, and the output torque capacity of the motor rotor is improved.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and in particular to a planetary coaxial powertrain and an electric vehicle. Background Technology

[0002] In a planetary coaxial powertrain, the drive motor, as the core device converting electrical energy into mechanical energy, has a rotor structure design that directly affects its operating efficiency and reliability. Under high-speed rotation, the rotor core must withstand enormous centrifugal loads. Since the drive motor shaft cavity needs to house the transmission shaft used to transmit power and drive the wheels, the inner diameter of the rotor core's central hole must be increased to meet the assembly requirements of this shaft. However, increasing the inner diameter of the rotor core's central hole significantly weakens the support stiffness of the core's central region. This causes the centrifugal force, originally mainly borne by the magnetic bridge region, to be transferred and act more on the peripheral walls and corners of the magnet slots. Long-term stress accumulation can easily lead to plastic deformation and even fatigue cracks in the magnet slots, resulting in magnet loosening, displacement, or even breakage. This severely affects the structural integrity and operational stability of the rotor core, necessitating improvements to the rotor core's stress distribution structure. Summary of the Invention

[0003] This application provides a planetary coaxial powertrain and an electric vehicle, which enables the motor rotor of the drive motor to have strong mechanical strength while reducing magnetic leakage and improving the output torque capacity of the motor rotor.

[0004] In a first aspect, this application provides a planetary coaxial powertrain, comprising a drive motor, a planetary reducer, and a drive shaft. The planetary reducer receives power output from the drive motor and drives the wheels of an electric vehicle via the drive shaft. The drive motor rotor includes a motor shaft and a rotor core. The drive motor shaft passes through a central hole in the rotor core, and the drive shaft passes through the drive motor shaft. Both ends of the drive shaft are used for transmission connections to the planetary reducer and the wheels, respectively. The rotor core includes multiple magnetic bridges distributed around the central hole, each magnetic bridge separating two magnetic slots in a V-shaped magnetic slot. The rotor core also includes multiple sets of first magnetic slots, each set comprising multiple first magnetic slots, which are radially spaced along the magnetic bridges of the drive motor.

[0005] In this embodiment, by using magnetic bridges to separate the two magnetic slots in the V-shaped magnetic slots, the rotor core can be connected into a whole through the magnetic bridges. This also facilitates stress dispersion using multiple magnetic bridges, resulting in stronger mechanical strength of the rotor core. This allows the motor rotor to resist centrifugal force at high speeds, ensuring structural integrity and improving the rotor's torque output capability. A set of first magnetic slots is arranged in each magnetic bridge. These slots reduce magnetic leakage, improving the rotor's torque output capability. They also disperse stress on the magnetic slots, further enhancing the rotor core's mechanical strength. Furthermore, the multiple first magnetic slots in each set are distributed radially along the drive motor, increasing the area of ​​the magnetic bridge between the two magnetic slots in each V-shaped magnetic slot. This allows the motor rotor to have strong mechanical strength while reducing magnetic leakage, thus improving its torque output capability.

[0006] In one embodiment, the area of ​​at least one of the plurality of first magnetic isolation slots is greater than the area of ​​the other first magnetic isolation slots among the plurality of first magnetic isolation slots.

[0007] In the embodiments of this application, at least one of the first magnetic isolation slots has a larger area. The larger the area of ​​the first magnetic isolation slot, the larger the space occupied by the magnetic isolation bridge. This is beneficial to better reduce the magnetic leakage of magnetic lines of force generated by the magnets in the magnetic steel slot from the magnetic isolation bridge, which is beneficial to improve the output torque of the motor rotor and improve the performance of the drive motor.

[0008] In the embodiments of this application, the area of ​​the other first magnetic isolation slots among the plurality of first magnetic isolation slots is smaller, so that the area occupied by the plurality of first magnetic isolation slots as a whole can be smaller, and the mechanical strength of the magnetic isolation bridge is stronger, which is beneficial to improving the mechanical strength of the rotor core, improving the structural reliability of the drive motor, and also beneficial to improving the output torque of the motor rotor.

[0009] In one embodiment, the area of ​​the plurality of first magnetic isolation grooves decreases sequentially along the direction away from the central hole.

[0010] In this embodiment, the area of ​​the plurality of first magnetic isolation grooves decreases sequentially along the direction away from the central hole. The area of ​​the first magnetic isolation groove closer to the central hole is larger, which makes it easier to use the larger area of ​​the first magnetic isolation groove to disperse the stress borne by the two magnetic grooves in each V-shaped magnetic groove. This is beneficial to improving the mechanical strength of the drive motor under high-speed operation and improving the performance of the drive motor.

[0011] In this embodiment, the area of ​​the first magnetic isolation groove away from the central hole is small, which makes it easier for the magnetic isolation bridge to be used in the larger area of ​​the first magnetic isolation groove with a smaller distribution area. This can make the mechanical strength of the rotor core stronger, which is beneficial to improving the reliability of the drive motor and the output torque of the motor rotor.

[0012] In this embodiment, the smaller area of ​​the first magnetic isolation slot away from the central hole helps prevent it from crowding the magnetic circuit, resulting in lower magnetic resistance and improved torque output capability of the motor rotor. The smaller area of ​​the first magnetic isolation slot away from the central hole also allows for more space to be reserved for other magnetic slots on the radial side of each V-shaped magnetic slot away from the central hole of the drive motor.

[0013] In this embodiment, since the stress is greater in the part of the rotor core closer to the center hole, the area of ​​the multiple first magnetic isolation slots is reduced sequentially along the direction away from the center hole, which can make the stress distribution of the multiple first magnetic isolation slots more uniform and the effect better.

[0014] In one embodiment, the magnetic bridge includes a first segment and a second segment. The distance between the first segment and the central hole along the radial direction of the drive motor is less than the distance between the second segment and the central hole, and the size of the first segment along the circumferential direction of the drive motor is greater than the size of the second segment.

[0015] In this embodiment, the first segment of the magnetic bridge is closer to the central hole, resulting in a larger dimension of the first segment along the circumference of the drive motor. This increases the mechanical strength of the rotor core and is beneficial for increasing the output torque of the motor rotor. The larger dimension of the first segment along the circumference of the drive motor also facilitates better stress distribution on both sides of the first segment of the magnetic bridge along the circumference of the drive motor, which is beneficial for improving the overall mechanical strength of the motor rotor and enhancing the performance of the drive motor.

[0016] In this embodiment, the second segment of the magnetic bridge is far from the central hole, and the size of the second segment is small along the circumference of the drive motor, which helps to reduce magnetic leakage and improves the torque output capability of the motor rotor.

[0017] In one embodiment, the dimension of the first segment along the circumference of the drive motor gradually decreases in the direction away from the central hole.

[0018] In this embodiment, the first segment's circumferential dimension along the drive motor gradually decreases in the direction away from the central hole, making the first segment of the magnetic bridge smoother. This facilitates more uniform stress distribution and a gentler stress distribution, thereby reducing peak stress and improving the mechanical strength of the rotor core. Since the portion of the rotor core closer to the central hole experiences greater stress, making the first segment, closer to the central hole, larger in its circumferential dimension along the drive motor makes it easier to utilize the first segment to enhance the mechanical strength of the rotor core, thus increasing the output torque of the motor rotor. It also helps prevent tip discharge in the first segment, improving the reliability of the drive motor.

[0019] In one embodiment, the size of the first segment along the circumference of the drive motor is larger than the size of the second segment, and the size of the first segment along the circumference of the drive motor gradually decreases in the direction away from the central hole.

[0020] In this embodiment, the dimension of the first segment along the circumference of the drive motor is larger than that of the second segment, while the dimension of the second segment is smaller. Gradually decreasing the dimension of the first segment along the circumference of the drive motor away from the central hole facilitates a smoother connection between the first and second segments, allowing for a seamless transition. This also helps to utilize the magnetic bridge to distribute stress and improve the mechanical strength of the rotor core. Furthermore, it helps prevent tip discharge and enhances the reliability of the drive motor.

[0021] In one embodiment, the magnetic bridge further includes a third segment, wherein the distance between the second segment and the center hole along the radial direction of the drive motor is less than the distance between the third segment and the center hole, and the dimension of the third segment along the circumferential direction of the drive motor is greater than the dimension of the second segment.

[0022] In this embodiment, the larger dimension of the third segment along the circumference of the drive motor is beneficial for increasing the cross-sectional area through which the magnetic lines of force generated by the magnets in the magnet slot pass. This provides a smoother path for the magnetic lines of force, thereby reducing magnetic resistance in the magnetic circuit and ultimately improving the output torque of the motor rotor and the performance of the drive motor. The larger distance between the third segment and the central hole along the radial direction of the drive motor, and the larger circumferential dimension of the third segment, also facilitates the arrangement of other magnet slots on the side of each V-shaped magnet slot away from the central hole.

[0023] In this embodiment, since the distance between the second segment and the center hole along the radial direction of the drive motor is smaller than the distance between the third segment and the center hole, the size of the second segment along the circumference of the drive motor is smaller. This is beneficial to make the spacing between the two magnet slots in each V-shaped magnet slot smaller, thereby reducing magnetic leakage and improving the output torque of the motor rotor.

[0024] In one embodiment, the dimension of the third segment along the circumference of the drive motor gradually increases in the direction away from the central hole.

[0025] In this embodiment, the first segment's circumferential dimension along the drive motor gradually decreases in the direction away from the central hole. This helps to distribute stress more evenly and smoothly in the third segment of the magnetic bridge, thereby reducing peak stress and improving the mechanical strength of the rotor core. The third segment, closer to the central hole, has a smaller circumferential dimension along the drive motor, which helps to reduce magnetic leakage, thereby increasing the output torque of the motor rotor and improving the drive motor performance.

[0026] In one embodiment, the dimension of the third segment along the circumference of the drive motor is larger than the dimension of the second segment, and the dimension of the third segment along the circumference of the drive motor gradually increases in the direction away from the central hole.

[0027] In this embodiment, since the dimension of the third segment along the circumference of the drive motor is larger than that of the second segment, and the dimension of the second segment along the circumference of the drive motor is smaller, gradually increasing the size of the third segment along the circumference of the drive motor in the direction away from the central hole facilitates a smoother connection between the third and second segments, resulting in a more even transition between them and better stress dispersion. This also helps prevent tip discharge and improves the reliability of the drive motor.

[0028] In one embodiment, the dimension of the first segment along the circumference of the drive motor is larger than that of the second segment, and the dimension of the first segment along the circumference of the drive motor gradually decreases in the direction away from the central hole. Similarly, the dimension of the third segment along the circumference of the drive motor is larger than that of the second segment, and the dimension of the third segment along the circumference of the drive motor gradually increases in the direction away from the central hole. This allows the first, second, and third segments of the magnetic bridge to better disperse stress, resulting in a smoother stress distribution across the magnetic bridge. This, in turn, helps to reduce peak stress and improve the structural strength of the rotor core.

[0029] In one embodiment, the maximum dimension of the first segment of the magnetic isolation bridge along the circumference of the drive motor is greater than the maximum dimension of the third segment along the circumference of the drive motor. The areas of the plurality of first magnetic isolation slots decrease sequentially along the direction away from the central hole.

[0030] In this embodiment, the first segment has a larger maximum dimension along the circumference of the drive motor, which facilitates the arrangement of the larger first magnetic isolation groove in the first segment. This allows the first magnetic isolation groove to be used to disperse stress, and also enables the larger first magnetic isolation groove to reduce magnetic leakage while ensuring that the larger first segment still has strong mechanical strength.

[0031] In one embodiment, each of the plurality of first magnetic isolation slots in each group of first magnetic isolation slots is a closed annular slot surrounded by an arc-shaped wall.

[0032] In this embodiment, the first magnetic isolation groove adopts an arc-shaped wall, which facilitates the guidance of the magnetic circuit, reduces magnetic leakage, and also helps to avoid tip discharge. The arc-shaped sidewall also helps to better disperse stress. The closed ring shape helps to improve the mechanical strength of the rotor core and prevents the motor rotor from deforming or being damaged due to the huge centrifugal force during high-speed rotation.

[0033] In one embodiment, each V-shaped magnet slot is used to accommodate two magnets, and the rotor core also includes multiple sets of second magnetic isolation slots. Each set of second magnetic isolation slots includes two second magnetic isolation slots. The two second magnetic isolation slots in each set are distributed between the magnetic isolation bridge and the two magnets accommodated by the V-shaped magnet slots. The area of ​​each second magnetic isolation slot is larger than the area of ​​the first magnetic isolation slot.

[0034] In this embodiment, since the magnetic lines of force generated by the magnets always tend to follow the path of least magnetic resistance, distributing the two second magnetic isolation slots in each group of second magnetic isolation slots between the magnetic isolation bridge and the two magnets contained in the V-shaped magnetic slots helps to prevent a large number of magnetic lines of force generated by the magnets from forming closed loops inside the rotor core, thereby preventing magnetic short circuits and guiding the magnetic lines of force generated by the magnets to flow to the motor stator, which helps to improve the output torque of the motor rotor.

[0035] In this embodiment, since the magnets are embedded in the magnet slots, when the drive motor rotates at high speed, the huge centrifugal force will throw the magnets outward. Distributing the two second magnetic isolation slots in each group between the magnetic isolation bridge and the two magnets contained in the V-shaped magnet slots is also beneficial to improving the mechanical strength of the rotor core, suppressing high-speed centrifugal force, and improving the performance of the drive motor.

[0036] In this embodiment, the area of ​​each second magnetic isolation slot is larger than that of the first magnetic isolation slot. The smaller distance between the second magnetic isolation slot and the magnet results in greater stress on the second magnetic isolation slot during rotor rotation. A larger area for the second magnetic isolation slot helps to better distribute stress and improves the reliability of the rotor core. A smaller area for the first magnetic isolation slot reduces the area occupied by the magnetic bridge, thus improving the mechanical strength of the rotor core, increasing the output torque of the motor rotor, and enhancing the performance of the drive motor.

[0037] In one embodiment, the minimum distance between the second magnetic isolation groove and the central hole is greater than the minimum distance between the first magnetic isolation groove and the central hole in each group of first magnetic isolation grooves.

[0038] In this embodiment, the minimum distance between the second magnetic isolation slot and the central hole is greater than the minimum distance between the first magnetic isolation slot and the central hole in each group of first magnetic isolation slots. Since the area of ​​the second magnetic steel slot is larger, a larger minimum distance between the second magnetic isolation slot and the central hole is beneficial for improving the mechanical strength of the rotor core, thereby improving the reliability of the drive motor. Because the second magnetic isolation slot is distributed between the magnet and the magnetic bridge, it experiences greater stress. A smaller minimum distance between the first magnetic isolation slot and the central hole in each group of first magnetic isolation slots facilitates the distribution of stress borne by the second magnetic isolation slot, which is beneficial for improving the mechanical reliability of the motor rotor and extending its service life. A smaller minimum distance between the first magnetic isolation slot and the central hole in each group of first magnetic isolation slots also facilitates the reduction of magnetic leakage, increasing the output torque of the motor rotor. Furthermore, the first magnetic isolation slots facilitate weight reduction of the rotor core.

[0039] In one embodiment, the second magnetic isolation groove includes a first side and a second side, which are distributed on both sides of the axis of symmetry of the magnetic groove. The distance between the first side and the central hole is less than the distance between the second side and the central hole, and the area of ​​the first side is less than the area of ​​the second side.

[0040] In this embodiment, the distance between the first side and the central hole is less than the distance between the second side and the central hole. Having a smaller area on the first side allows for a smaller protrusion of the second magnetically insulating groove towards the central hole, which helps improve the mechanical strength of the rotor core, thereby increasing the output torque of the motor rotor and improving the performance of the drive motor. Having a larger area on the second side allows for better stress distribution, further enhancing the mechanical strength of the motor rotor.

[0041] In one embodiment, the area of ​​the second side protruding from the magnet along the direction perpendicular to the axis of symmetry of the magnet slot is greater than the area of ​​the first side protruding from the magnet.

[0042] In this embodiment, the second side protrudes a larger area from the magnet slot along the direction perpendicular to the axis of symmetry of the magnet slot. This facilitates better stress dispersion on the second side of the second magnetic isolation slot, which is beneficial for improving the mechanical strength of the rotor core and increasing the output torque of the motor rotor. Conversely, the first side protrudes a smaller area from the magnet along the direction perpendicular to the axis of symmetry of the magnet slot. This allows the first side to be farther from the center hole, which is beneficial for improving the mechanical strength of the rotor core and increasing the torque output capability of the motor rotor.

[0043] In one embodiment, the maximum dimension of the second side along the direction perpendicular to the axis of symmetry of the magnet slot is greater than the maximum dimension of the first side.

[0044] In this embodiment, the maximum dimension of the second side along the direction perpendicular to the axis of symmetry of the magnet slot is greater than the maximum dimension of the first side, while the maximum dimension of the first side along the direction perpendicular to the axis of symmetry of the magnet slot is smaller. This allows the second magnetic isolation slot to protrude less towards the central hole along the direction perpendicular to the axis of symmetry of the magnet slot, resulting in a greater distance between the second magnetic isolation slot and the central hole. This is beneficial for improving the mechanical strength of the rotor core, thereby enhancing the torque output capability of the motor rotor. The larger maximum dimension of the second side along the direction perpendicular to the axis of symmetry of the magnet slot results in a longer overall length of the second magnetic isolation slot along this direction. This is more conducive to utilizing the second magnetic isolation slot to disperse stress, further enhancing the mechanical strength of the rotor core and improving the torque output capability of the motor rotor.

[0045] In one embodiment, the area of ​​the first side is smaller than the area of ​​the second side, and the maximum dimension of the second side is greater than the maximum dimension of the first side along the direction perpendicular to the axis of symmetry of the magnet slot.

[0046] In this embodiment, since the area of ​​the first side is large, the maximum dimension of the first side along the direction perpendicular to the axis of symmetry of the magnet slot is large, which makes it easier to make the dimension of the first side along the axis of symmetry of the magnet slot smaller, which makes it easier to make the dimension of the magnetic bridge between the two second magnetic isolation slots larger along the circumferential direction of the drive motor, thereby improving the mechanical strength of the rotor core.

[0047] In one embodiment, the dimension of the first side along the axis of symmetry of the magnetic slot gradually decreases in the direction toward the central hole. This allows the portion of the first side of the second magnetic isolation slot near the central hole to be smaller, thereby reducing the stress on the second magnetic isolation slot, improving the mechanical strength of the rotor core, and thus improving the output torque of the motor rotor.

[0048] In one embodiment, the radius of curvature of the second side of the second magnetic isolation groove facing away from the central hole is greater than the radius of curvature of the first side facing the central hole, and the area of ​​the second side is greater than the area of ​​the first side.

[0049] In this embodiment, since the second magnetic isolation groove is distributed between the magnet and the magnetic isolation bridge, the radius of curvature of the second side away from the central hole is larger. This is beneficial because it minimizes the protrusion of the second side toward the outer periphery of the rotor core, resulting in a wider magnetic circuit and lower magnetic resistance. The larger radius of curvature on the side away from the central hole also improves the stress dispersion effect on the second side.

[0050] In this embodiment, the radius of curvature of the side of the second side away from the central hole is larger, which also helps to make the area of ​​the second side larger, thereby helping to better disperse stress on the second side, which helps to improve the mechanical strength of the motor rotor and the output torque of the motor rotor.

[0051] In one embodiment, the minimum distance between the second magnetic isolation groove and the first magnetic isolation groove is less than the maximum dimension of the second magnetic isolation groove along the direction perpendicular to the axis of symmetry of the magnetic groove.

[0052] In this embodiment, the minimum distance between the second magnetic isolation slot and the first magnetic isolation slot is less than the maximum dimension of the second magnetic isolation slot along the direction perpendicular to the axis of symmetry of the magnet slot. A smaller minimum distance between the second and first magnetic isolation slots allows for a narrower magnetic bridge portion between them, reducing magnetic leakage and improving the output torque of the motor rotor and the performance of the drive motor. A larger maximum dimension of the second magnetic isolation slot along the direction perpendicular to the axis of symmetry of the magnet slot allows for a larger area, resulting in better stress dispersion and improved mechanical strength of the rotor core. This, in turn, enhances the reliability of the motor rotor and the performance of the drive motor.

[0053] In one embodiment, the minimum dimension of the magnetic isolation bridge along the circumference of the drive motor is greater than the dimension of the second magnetic isolation groove along the axis of symmetry of the magnet groove.

[0054] In this embodiment, the minimum dimension of the magnetic isolation bridge along the circumference of the drive motor is larger than the dimension of the second magnetic isolation slot along the axis of symmetry of the magnet slot. A larger minimum dimension of the magnetic isolation bridge along the circumference of the drive motor helps to improve the mechanical strength of the rotor core, enhance the torque output capability of the motor rotor, and improve the performance of the drive motor. A smaller dimension of the second magnetic isolation slot along the axis of symmetry of the magnet slot allows for a smaller space occupied by the second magnetic isolation slot between the magnet and the magnetic isolation bridge. This also facilitates setting a larger magnetic isolation bridge, improving the mechanical strength of the rotor core, thereby enhancing the torque output capability of the motor rotor and improving the performance of the drive motor.

[0055] In one embodiment, the second side of the second magnetic isolation groove is away from the magnet along the axis of symmetry of the magnet groove, and the angle between the side of the second magnetic isolation groove away from the central hole and the side of the magnet groove away from the central hole is greater than 90 degrees and less than 180 degrees.

[0056] In this embodiment, the angle between the side of the second magnetic isolation groove facing away from the central hole and the side of the magnet groove facing away from the central hole is denoted as β. β is greater than 90 degrees and less than 180 degrees, which makes the second side of the second magnetic isolation groove protrude less towards the outer periphery of the rotor core. This is beneficial for making the magnetic circuit wider, reducing magnetic resistance, and improving the torque output capability of the motor rotor. It also helps to disperse the stress borne by the second magnetic isolation groove, resulting in stronger mechanical strength of the rotor core.

[0057] In one embodiment, the second magnetic isolation groove is formed by enclosing a magnet with arc-shaped sidewalls. The second magnetic isolation groove includes a first arc-shaped sidewall, a second arc-shaped sidewall, and a third arc-shaped sidewall. The first and second arc-shaped sidewalls are arranged opposite each other along a direction perpendicular to the axis of symmetry of the magnet groove. Along the radial direction of the drive motor, the first arc-shaped sidewall is closer to the center hole than the second arc-shaped sidewall. The third arc-shaped sidewall is opposite to the magnet along the axis of symmetry of the magnet groove. The radius of curvature of the third arc-shaped sidewall of the second magnetic isolation groove is greater than the radius of curvature of the first arc-shaped sidewall and greater than the radius of curvature of the second arc-shaped sidewall.

[0058] In this embodiment, the larger radius of curvature of the third arc-shaped sidewall is beneficial for making the dimensions of the second magnetic isolation slots smaller along the axis of symmetry of the magnet slots. This, in turn, allows for a larger spacing between the two second magnetic isolation slots between the two magnets accommodated in each V-shaped magnet slot, resulting in stronger mechanical strength of the motor rotor. It also facilitates the arrangement of multiple first magnetic isolation slots in each group of first magnetic isolation slots within the magnetic isolation bridge, reducing magnetic leakage. The larger radius of curvature of the third arc-shaped sidewall also helps to disperse stress, further enhancing mechanical strength. The smaller radii of curvature of the first and second arc-shaped sidewalls allow for a flatter second magnetic isolation slot along the axis of symmetry of the magnet slots, resulting in a larger circumferential dimension of the magnetic isolation bridge between each V-shaped magnet slot, thus improving the mechanical strength of the rotor core.

[0059] In one embodiment, the rotor core further includes a plurality of first magnetic isolation bridges, which are distributed around the first magnetic isolation bridges. Each first magnetic isolation bridge is used to separate two first magnetic slots in a first V-shaped magnetic slot. The minimum distance between the second magnetic isolation slot and the first magnetic isolation bridge is greater than the minimum distance between the first magnetic isolation slot and the first magnetic isolation bridge.

[0060] In this embodiment, since the magnetic lines of force generated by the magnets flow between the first magnet slots, the minimum distance between the second magnetic isolation slot and the first magnetic isolation bridge is larger. This allows the second magnetic isolation slot to occupy less of the magnetic circuit, resulting in lower magnetic resistance and improving the torque output capability of the motor rotor.

[0061] In one embodiment, the dimension of the first magnetic bridge along the circumference of the drive motor is smaller than the dimension of the magnetic bridge along the circumference of the drive motor.

[0062] In this embodiment, because the first magnetic isolation bridge is farther from the central hole than the other magnetic isolation bridge, it experiences less stress. Setting the first magnetic isolation bridge to have a smaller circumferential dimension along the drive motor also provides sufficient mechanical strength. Furthermore, the smaller circumferential dimension of the first magnetic isolation bridge helps reduce magnetic leakage and improves the rotor's torque output capability. The smaller circumferential dimension of the first magnetic isolation bridge also facilitates the arrangement of the two first magnetic slots in the first V-shaped magnetic slot.

[0063] Secondly, this application provides an electric vehicle, which includes wheels and a planetary coaxial powertrain as described in the first aspect, the planetary coaxial powertrain being used to drive the wheels.

[0064] The planetary coaxial powertrain in this embodiment includes a drive motor. By separating two magnetic slots in a V-shaped magnetic slot through each magnetic bridge of the rotor core, the mechanical strength of the rotor core is increased, which is beneficial to improving the torque output capability of the motor rotor. A set of first magnetic slots is arranged in each magnetic bridge to reduce magnetic leakage and improve the torque output capability of the motor rotor. The multiple first magnetic slots in each set are distributed radially along the drive motor, so that the area of ​​the magnetic bridge between the two magnetic slots in each V-shaped magnetic slot is larger. This is beneficial to reduce magnetic leakage while maintaining strong mechanical strength of the motor rotor, thereby improving the torque output capability of the motor rotor, improving the performance of the drive motor, improving the performance of the planetary coaxial powertrain, and ultimately improving the overall performance of the electric vehicle. Attached Figure Description

[0065] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0066] Figure 1This is a schematic diagram of an electric vehicle provided in an embodiment of this application; Figure 2 This is a schematic diagram of a planetary coaxial powertrain provided in an embodiment of this application; Figure 3 This is another schematic diagram of the planetary coaxial powertrain provided in the embodiments of this application; Figure 4 This is a schematic diagram of a motor rotor provided in an embodiment of this application; Figure 5 This is another schematic diagram of the motor rotor provided in the embodiments of this application; Figure 6 This is another schematic diagram of the motor rotor provided in the embodiments of this application; Figure 7 This is another schematic diagram of the motor rotor provided in the embodiments of this application; Figure 8 This is another schematic diagram of the motor rotor provided in the embodiments of this application; Figure 9 yes Figure 8 A partial enlarged view of the M1 section of the motor rotor; Figure 10 This is another schematic diagram of the motor rotor provided in the embodiments of this application; Figure 11a This is a local stress contour plot of the rotor core provided in this application as a comparative example; Figure 11b This is a local stress cloud diagram of the rotor core provided in this application; Figure 12a This is a partial magnetic field line and magnetic flux density diagram of a rotor core provided in this application as a comparative example; Figure 12b This is a partial magnetic field line and magnetic flux density diagram of the rotor core provided in the embodiments of this application. Detailed Implementation

[0067] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0068] This application provides a planetary coaxial powertrain including a drive motor, a planetary reducer, and a drive shaft. The planetary reducer receives power output from the drive motor and drives the wheels of an electric vehicle via the drive shaft. The drive motor rotor includes a motor shaft and a rotor core. The drive motor shaft passes through a central hole in the rotor core. The drive shaft passes through the drive motor shaft, and its two ends are used for transmission connections to the planetary reducer and the wheels, respectively. The rotor core includes multiple magnetic bridges distributed around the central hole. Each magnetic bridge separates two magnetic slots in a V-shaped magnetic slot. The rotor core also includes multiple sets of first magnetic slots, each set comprising multiple first magnetic slots. These multiple first magnetic slots are distributed radially along the magnetic bridges of the drive motor.

[0069] By using magnetic bridges to separate the two magnetic slots in the V-shaped magnetic slots, the mechanical strength of the rotor core is increased, improving the rotor's torque output capability. A set of first magnetic isolation slots is arranged in each magnetic bridge to reduce magnetic leakage from the bridge, further enhancing the rotor's torque output capability. These slots also disperse stress on the magnetic slots, contributing to the improved mechanical strength of the rotor core. Furthermore, the multiple first magnetic isolation slots in each set are distributed radially along the drive motor, resulting in a larger magnetic bridge area between the two slots in each V-shaped magnetic slot. This reduces the structural strength of the rotor core, allowing for both strong mechanical properties and reduced magnetic leakage, thus improving the rotor's output torque and overall drive motor performance.

[0070] The planetary coaxial powertrain provided in this application embodiment can be applied to electric vehicles to improve the overall performance of electric vehicles.

[0071] Figure 1 This is a schematic diagram of an electric vehicle 1 provided in an embodiment of this application. Figure 2 This is a schematic diagram of a planetary coaxial powertrain 10 provided in an embodiment of this application. Figure 3 This is another schematic diagram of the planetary coaxial powertrain 10 provided in the embodiments of this application.

[0072] In one embodiment, the electric vehicle 1 includes a planetary coaxial powertrain 10 and wheels 20, such as Figure 1 As shown. The planetary coaxial powertrain 10 is used to drive the wheels 20.

[0073] In one embodiment, such as Figure 2 and Figure 3 As shown, the planetary coaxial powertrain 10 includes a drive motor 11 and a planetary reducer 12, which receives the power output from the drive motor 11. The drive motor 11 and the planetary reducer 12 are arranged along the axial direction O of the drive motor 11.

[0074] In the embodiments of this application, such as Figure 3 As shown, the drive motor 11 includes a motor stator 100 and a motor rotor 200. The motor rotor 200 includes a motor shaft 210 and a rotor core 220. The planetary reducer 12 includes a gear set (not shown). The motor shaft 210 of the drive motor 11 passes through the central hole 221 of the rotor core 220, so that the rotor core 220 of the motor rotor 200 is fixedly sleeved on the motor shaft 210 of the drive motor 11. When the rotor core 220 rotates, it can directly drive the motor shaft 210 to rotate. The motor shaft 210 of the drive motor 11 is used to transmit kinetic energy to the gear set of the planetary reducer 12.

[0075] In one embodiment, such as Figure 2 and Figure 3 As shown, the planetary coaxial powertrain 10 includes a drive shaft 13, a planetary reducer 12 for driving the wheels 20 of the electric vehicle 1 through the drive shaft 13, the drive shaft 13 passing through the motor shaft 210 of the drive motor 11, and the two ends of the drive shaft 13 for transmission connection between the planetary reducer 12 and the wheels 20, respectively. This allows the power reduced by the planetary reducer 12 to drive the wheels 20 of the electric vehicle 1 through the drive shaft 13.

[0076] In one embodiment, such as Figures 1 to 3 As shown, the planetary coaxial powertrain 10 includes a motor controller 14, which receives power from the power battery 30 of the electric vehicle 1. After receiving the current provided by the motor controller 14, the motor stator 100 drives the rotor core 220 of the motor rotor 200 to rotate, thereby driving the motor shaft 210 to rotate.

[0077] In one embodiment, such as Figure 2 and Figure 3 As shown, the stator 100 of the drive motor 11 includes a stator core 110 and a stator winding 120. Along the axial direction of the drive motor 11, the end winding 121 of the stator winding 120 is exposed on one side of the stator core 110. The end winding 121 is connected to the motor controller 14 through the outgoing copper busbar to receive three-phase AC power, thereby driving the motor rotor 200 to rotate.

[0078] Because the drive shaft in the planetary coaxial powertrain needs to pass through the central hole of the rotor core of the drive motor, the V-shaped magnet slots near the central hole are close to the central hole. The V-shaped magnet slots bear a lot of stress, resulting in poor mechanical strength of the motor rotor and reduced motor rotor torque.

[0079] This application improves the torque output capability of the motor rotor by using a magnetic bridge between two magnet slots in each V-shaped magnet slot, which is distributed radially along the drive motor by multiple first magnetic isolation slots. This allows the magnetic bridge to enhance the mechanical strength of the rotor core while the first magnetic isolation slots to reduce magnetic leakage.

[0080] The planetary coaxial powertrain 10 provided in the embodiments of this application will be described in detail below.

[0081] Figure 4 This is a schematic diagram of a motor rotor 200 provided in an embodiment of this application. Figure 5 This is another schematic diagram of the motor rotor 200 provided in the embodiments of this application.

[0082] In one embodiment, such as Figure 4 As shown, the rotor core 220 of the motor rotor 200 includes a plurality of V-shaped magnetic slots 222. The plurality of V-shaped magnetic slots 222 are arranged at intervals around the central hole 221 along the circumferential direction C of the drive motor 11. Each V-shaped magnetic slot 222 includes two magnetic slots 222a, wherein each magnetic slot 222a is used to accommodate at least one magnet 230. The opening direction of each V-shaped magnetic slot 222 is away from the central hole 221 along the radial direction R of the drive motor 11.

[0083] In one embodiment, such as Figure 4 and Figure 5 As shown, the rotor core 220 of the motor rotor 200 includes multiple magnetic isolation bridges 223, which are distributed around the central hole 221. Each magnetic isolation bridge 223 is used to separate two magnetic slots 222a in a V-shaped magnetic slot 222.

[0084] In this embodiment, the rotor core 220 includes multiple magnetic isolation bridges 223. Each magnetic isolation bridge 223 is used to divide two magnetic slots 222a in a V-shaped magnetic slot 222, so that the rotor core 220 can be connected into a whole by the magnetic isolation bridges 223. It is also easier to use multiple magnetic isolation bridges 223 to disperse stress, which helps to make the rotor core 220 have stronger mechanical strength, so that the motor rotor 200 can resist centrifugal force under high speed rotation, ensure structural integrity, and also help to improve the output torque of the motor rotor 200 and improve the performance of the drive motor 11.

[0085] In the embodiments of this application, such as Figure 3 and Figure 4As shown, since the drive shaft 13 passes through the motor shaft 210 of the drive motor 11, the shaft cavity size of the motor shaft 210 needs to be increased. Since the motor shaft 210 passes through the central hole 221 of the rotor core 220, the inner diameter of the central hole 221 of the rotor core 220 needs to be larger. This results in a smaller distance between the two magnetic slots 222a in each V-shaped magnetic slot 222 and the central hole 221 along the radial direction R of the drive motor 11. The closer the magnetic slot 222a is to the central hole 221, the greater the stress it bears, thus affecting the mechanical strength of the motor rotor 200. This solution distributes multiple magnetic isolation bridges 223 around the central hole 221, so that each magnetic isolation bridge 223 divides two magnetic slots 222a in one V-shaped magnetic slot 222. Utilizing multiple magnetic isolation bridges 223 improves the overall mechanical strength of the rotor core 220, which is beneficial for increasing the output torque of the motor rotor 200 and improving the overall performance of the drive motor 11.

[0086] In one embodiment, such as Figure 4 and Figure 5 As shown, the rotor core 220 also includes multiple sets of first magnetic isolation slots 224. Each set of first magnetic isolation slots 224 includes multiple first magnetic isolation slots 224a. The multiple first magnetic isolation slots 224a in each set of first magnetic isolation slots 224 are distributed at intervals along the radial direction R of the drive motor 11 on the magnetic isolation bridge 223.

[0087] In this embodiment, the rotor core 220 includes multiple sets of first magnetic isolation slots 224. Each set of first magnetic isolation slots 224 is distributed on the magnetic isolation bridge 223, thereby reducing the leakage of magnetic lines of force generated by the magnets 230 in the two magnet slots 222a in each V-shaped magnet slot 222 from the magnetic isolation bridge 223. This allows more magnetic lines of force to pass through the air gap between the motor rotor 200 and the motor stator 100, which is beneficial to improving the output torque of the motor rotor 200 and improving the performance of the drive motor 11.

[0088] In this embodiment of the application, the first magnetic isolation groove 224a is distributed in the magnetic isolation bridge 223 between the two magnetic grooves 222a of each V-shaped magnetic groove 222, so that the first magnetic isolation groove 224a can also be used to disperse the stress on the magnetic groove 222a, which is also beneficial to improve the mechanical strength of the rotor core 220.

[0089] In this embodiment, each group of first magnetic isolation slots 224 includes multiple first magnetic isolation slots 224a. The multiple first magnetic isolation slots 224a are distributed at intervals along the radial direction R of the drive motor 11 on the magnetic isolation bridge 223. This allows the magnetic isolation bridge 223 between the two magnetic slots 222a in each V-shaped magnetic slot 222 to be wider along the circumferential direction C of the drive motor 11. This results in more connected iron core portions between the two magnetic slots 222a in each V-shaped magnetic slot 222, which is beneficial to improving the mechanical strength of the rotor iron core 220. This allows for reducing magnetic leakage while ensuring that the motor rotor 200 has good mechanical strength, which is beneficial to improving the output torque of the motor rotor 200.

[0090] In one embodiment, such as Figure 4 and Figure 5 As shown, the rotor core 220 includes multiple magnetic isolation bridges 223, which are distributed around the central hole 221. Each magnetic isolation bridge 223 is used to separate two magnetic slots 222a in a V-shaped magnetic slot 222. The rotor core 220 also includes multiple sets of first magnetic isolation slots 224, each set of first magnetic isolation slots 224 including multiple first magnetic isolation slots 224a. The multiple first magnetic isolation slots 224a in each set of first magnetic isolation slots 224 are distributed at intervals along the radial direction R of the drive motor 11 on the magnetic isolation bridges 223.

[0091] In this embodiment, a magnetic bridge 223 is used to separate two magnetic slots 222a in the V-shaped magnetic slots 222, resulting in stronger mechanical strength of the rotor core 220, which is beneficial for improving the torque output capability of the motor rotor 200. A set of first magnetic slots 224 is arranged in each magnetic bridge 223. The first magnetic slots 224a reduce magnetic leakage, which can improve the torque output capability of the motor rotor 200. The first magnetic slots 224a can also disperse the stress on the magnetic slots 222a, which is also beneficial for improving the mechanical strength of the rotor core 220. The multiple first magnetic slots 224a in each set of first magnetic slots 224 are distributed at intervals along the radial direction R of the drive motor 11, so that the area of ​​the magnetic bridge 223 separating the two magnetic slots 222a in each V-shaped magnetic slot 222 is larger. This is beneficial for the motor rotor 200 to have strong mechanical strength while reducing magnetic leakage, thereby improving the torque output capability of the motor rotor 200.

[0092] In one embodiment, such as Figure 5 As shown, the plurality of first magnetic isolation grooves 224a include two first magnetic isolation grooves 224a, and the two first magnetic isolation grooves 224a have equal areas.

[0093] In this embodiment of the application, two first magnetic isolation slots 224a are arranged at a radial R interval along the drive motor 11 in each magnetic isolation bridge 223. This makes it easier for the first magnetic isolation slots 224a to occupy a small area of ​​the magnetic isolation bridge 223, thereby making the magnetic isolation bridge 223 have a stronger mechanical strength. This is beneficial to make the rotor core 220 have a stronger mechanical strength while reducing magnetic leakage, and can also improve the torque output capability of the motor rotor 200.

[0094] Figure 6 This is another schematic diagram of the motor rotor 200 provided in the embodiments of this application. Figure 7 This is another schematic diagram of the motor rotor 200 provided in the embodiments of this application. Figure 8 This is another schematic diagram of the motor rotor 200 provided in the embodiments of this application.

[0095] In one embodiment, such as Figures 6 to 8 As shown, the area of ​​at least one first magnetic isolation groove 224b among the plurality of first magnetic isolation grooves 224a is greater than the area of ​​the other first magnetic isolation grooves 224c among the plurality of first magnetic isolation grooves 224a.

[0096] In this embodiment, at least one of the first magnetic isolation grooves 224a has a larger area. The larger the area of ​​the first magnetic isolation groove 224b, the larger the space occupied by the magnetic isolation bridge 223. This is beneficial to better reduce the magnetic leakage of magnetic lines generated by the magnet 230 in the magnetic groove 222a from the magnetic isolation bridge 223, which is beneficial to improve the output torque of the motor rotor 200 and improve the performance of the drive motor 11.

[0097] In this embodiment, the area of ​​the other first magnetic isolation slots 224c among the plurality of first magnetic isolation slots 224a is smaller, which is beneficial to make the area of ​​the magnetic isolation bridge 223 occupied by the plurality of first magnetic isolation slots 224a smaller, making the mechanical strength of the magnetic isolation bridge 223 stronger, which is beneficial to improve the mechanical strength of the rotor core 220, improve the structural reliability of the drive motor 11, and also beneficial to improve the output torque of the motor rotor 200.

[0098] In one embodiment, such as Figure 6 and Figure 8 As shown, the area of ​​the plurality of first magnetic isolation grooves 224a decreases sequentially along the direction A away from the central hole 221.

[0099] In this embodiment, the area of ​​the plurality of first magnetic isolation grooves 224a decreases sequentially along the direction away from the central hole 221. The area of ​​the first magnetic isolation groove 224a closer to the central hole 221 is larger, which makes it easier to use the larger area of ​​the first magnetic isolation groove 224a to disperse the stress borne by the two magnetic grooves 222a in each V-shaped magnetic groove 222. This is beneficial to improving the mechanical strength of the drive motor 11 under high-speed operation and improving the performance of the drive motor 11.

[0100] In this embodiment, the area of ​​the first magnetic isolation groove 224a away from the central hole 221 is small, which makes it easier for the magnetic isolation bridge 223 to be used for a larger area of ​​the portion of the first magnetic isolation groove 224a with a smaller distribution area. This can make the mechanical strength of the rotor core 220 stronger, which is beneficial to improving the reliability of the drive motor 11 and the output torque of the motor rotor 200.

[0101] In this embodiment, the area of ​​the first magnetic isolation groove 224a away from the central hole 221 is small, which helps to prevent the first magnetic isolation groove 224a away from the central hole 221 from crowding the magnetic circuit, and helps to reduce the magnetic resistance and improve the torque output capability of the motor rotor 200. The small area of ​​the first magnetic isolation groove 224a away from the central hole 221 also makes it easier to reserve more space for other magnetic grooves to be arranged on the side of each V-shaped magnetic groove 222 away from the central hole 221 along the radial R of the drive motor 11.

[0102] In this embodiment, since the stress on the part of the rotor core 220 closer to the center hole 221 is greater, the area of ​​the multiple first magnetic isolation grooves 224a is reduced sequentially along the direction away from the center hole 221, so that the stress of the multiple first magnetic isolation grooves 224a can be distributed more evenly and the effect is better.

[0103] In one embodiment, such as Figure 8 As shown, the magnetic bridge 223 includes a first segment 2231 and a second segment 2232. The distance between the first segment 2231 and the center hole 221 along the radial direction R of the drive motor 11 is less than the distance between the second segment 2232 and the center hole 221. The size of the first segment 2231 along the circumferential direction C of the drive motor 11 is greater than the size of the second segment 2232.

[0104] In this embodiment, the first segment 2231 of the magnetic bridge 223 is closer to the central hole 221, resulting in a larger size of the first segment 2231 along the circumferential direction C of the drive motor 11, which is beneficial to improving the mechanical strength of the rotor core 220. The larger size of the first segment 2231 along the circumferential direction C of the drive motor 11 also facilitates better stress distribution on both sides of the first segment 2231 along the circumferential direction C of the drive motor 11, which is beneficial to improving the overall mechanical strength of the motor rotor 200, increasing the output torque of the motor rotor 200, and improving the performance of the drive motor 11.

[0105] In this embodiment, the second segment 2232 of the magnetic isolation bridge 223 is far from the center hole 221. The size of the second segment 2232 is small along the circumferential direction C of the drive motor 11, which helps to reduce magnetic leakage and improves the torque output capability of the motor rotor 200.

[0106] In one embodiment, such as Figure 8As shown, the dimension of the first segment 2231 along the circumferential C of the drive motor 11 gradually decreases along the direction A away from the center hole 221.

[0107] In this embodiment, the first segment 2231 gradually decreases in size along the circumferential direction C of the drive motor 11 in the direction away from the central hole 221. This makes the first segment 2231 of the magnetic bridge 223 smoother, which helps to distribute stress more evenly and gradually, thereby reducing peak stress and improving the mechanical strength of the rotor core 220. Since the part of the rotor core 220 closer to the central hole 221 bears greater stress, making the portion of the first segment 2231 closer to the central hole 221 larger along the circumferential direction C of the drive motor 11 makes it easier to improve the mechanical strength of the rotor core 220, which is beneficial to increasing the output torque of the motor rotor 200. It also helps to prevent tip discharge in the first segment 2231, improving the reliability of the drive motor 11.

[0108] In one embodiment, such as Figure 8 As shown, the size of the first segment 2231 along the circumferential direction C of the drive motor 11 is larger than the size of the second segment 2232, and the size of the first segment 2231 along the circumferential direction C of the drive motor 11 gradually decreases along the direction A away from the center hole 221.

[0109] In this embodiment, the size of the first segment 2231 along the circumferential direction C of the drive motor 11 is larger than the size of the second segment 2232, while the size of the second segment 2232 is smaller. Gradually decreasing the size of the first segment 2231 along the circumferential direction C of the drive motor 11 in the direction A away from the central hole 221 facilitates a smoother connection between the first segment 2231 and the second segment 2232, allowing for a smooth transition. This also helps to utilize the magnetic bridge 2233 to distribute stress between the first and second segments 2231 and 2232. Furthermore, it helps prevent tip discharge and improves the reliability of the drive motor 11.

[0110] In one embodiment, such as Figure 8 As shown, the magnetic bridge 223 also includes a third segment 2233. The distance between the second segment 2232 and the center hole 221 along the radial direction R of the drive motor 11 is less than the distance between the third segment 2233 and the center hole 221. The size of the third segment 2233 along the circumferential direction C of the drive motor 11 is greater than the size of the second segment 2232.

[0111] In this embodiment, the larger size of the third segment 2233 along the circumferential direction C of the drive motor 11 is beneficial for increasing the cross-sectional area through which the magnetic lines of force generated by the magnet 230 pass within the magnet slot 222a. This provides a smoother path for the magnetic lines of force, thereby reducing magnetic resistance in the magnetic circuit and improving the output torque of the motor rotor 200, thus enhancing the performance of the drive motor 11. The larger distance between the third segment 2233 and the central hole 221 along the radial direction R of the drive motor 11, and the larger size of the third segment 2233 along the circumferential direction C of the drive motor 11, also facilitates the arrangement of other magnet slots on the side of each V-shaped magnet slot 222 away from the central hole 221.

[0112] In this embodiment, since the distance between the second segment 2232 and the center hole 221 along the radial direction R of the drive motor 11 is smaller than the distance between the third segment 2233 and the center hole 221, the size of the second segment 2232 along the circumferential direction C of the drive motor 11 is smaller. This is beneficial to make the spacing between the two magnet slots 222a in each V-shaped magnet slot 222 smaller, which is beneficial to reduce magnetic leakage and improve the output torque of the motor rotor 200.

[0113] In one embodiment, such as Figure 8 As shown, the dimension of the third segment 2233 along the circumferential C of the drive motor 11 gradually increases along the direction A away from the center hole 221.

[0114] In this embodiment, the first segment 2231, along the circumferential direction C of the drive motor 11, gradually decreases in size along the direction A away from the central hole 221. This helps to distribute stress more evenly in the third segment 2233 of the magnetic isolation bridge 223, resulting in a smoother stress distribution. This, in turn, helps to reduce peak stress and improve the mechanical strength of the rotor core 220. The third segment 2233, which is closer to the central hole 221, has a smaller circumferential dimension C along the drive motor 11, which helps to reduce magnetic leakage. This, in turn, helps to increase the output torque of the motor rotor 200 and improve the performance of the drive motor 11.

[0115] In one embodiment, the size of the third segment 2233 along the circumferential direction C of the drive motor 11 is larger than the size of the second segment 2232, and the size of the third segment 2233 along the circumferential direction C of the drive motor 11 gradually increases in the direction A away from the central hole 221.

[0116] In this embodiment, the dimension of the third segment 2233 along the circumferential direction C of the drive motor 11 is larger than the dimension of the second segment 2232, while the dimension of the second segment 2232 along the circumferential direction C of the drive motor 11 is smaller. The third segment 2233 gradually increases in size along the circumferential direction C of the drive motor 11 in the direction A away from the central hole 221. This facilitates a smoother connection between the third segment 2233 and the second segment 2232, resulting in a smoother transition and better stress dispersion. It also helps prevent tip discharge and improves the reliability of the drive motor 11.

[0117] In one embodiment, the dimension of the first segment 2231 along the circumferential direction C of the drive motor 11 is larger than the dimension of the second segment 2232. The dimension of the first segment 2231 along the circumferential direction C of the drive motor 11 gradually decreases along the direction A away from the central hole 221. The dimension of the third segment 2233 along the circumferential direction C of the drive motor 11 is larger than the dimension of the second segment 2232. The dimension of the third segment 2233 along the circumferential direction C of the drive motor 11 gradually increases along the direction A away from the central hole 221. This allows the first segment 2231, the second segment 2232, and the third segment 2233 of the magnetic isolation bridge 223 to better disperse stress, making the stress distribution of the magnetic isolation bridge 223 more gradual. This helps to reduce peak stress and improve the structural strength of the rotor core 220.

[0118] In one embodiment, such as Figure 8 As shown, the maximum dimension of the first segment 2231 of the magnetic isolation bridge 223 along the circumferential direction C of the drive motor 11 is greater than the maximum dimension of the third segment 2233 along the circumferential direction C of the drive motor 11. The areas of the plurality of first magnetic isolation grooves 224a decrease sequentially along the direction away from the central hole 221.

[0119] In this embodiment, the first segment 2231 has a larger maximum dimension along the circumferential direction C of the drive motor 11, which makes it easier to arrange the larger first magnetic isolation groove 224a in the first segment 2231. This makes it easier to use the first magnetic isolation groove 224a to disperse stress, and also allows the larger first magnetic isolation groove 224a to reduce magnetic leakage while ensuring that the larger first segment 2231 still has strong mechanical strength.

[0120] In one embodiment, such as Figure 8 As shown, each of the multiple first magnetic isolation grooves 224a in each group of first magnetic isolation grooves 224 is a closed ring groove surrounded by an arc-shaped wall.

[0121] In this embodiment, the first magnetic isolation groove 224a adopts an arc-shaped wall, which facilitates the guidance of the magnetic circuit, reduces magnetic leakage, and also helps to avoid tip discharge. The arc-shaped sidewall also helps to better disperse stress. The closed ring shape helps to improve the mechanical strength of the rotor core 220 and prevent the motor rotor 200 from deforming or being damaged due to the huge centrifugal force when rotating at high speed.

[0122] In one embodiment, the shape of the first magnetic isolation groove 224a includes one or more of the following: circular, elliptical, rounded rectangle, and closed multi-segment arc. This can prevent the first magnetic isolation groove 224a from generating tip discharge and also facilitates better stress dispersion in the first magnetic isolation groove 224a.

[0123] In one embodiment, such as Figure 4 and Figure 8 As shown, each V-shaped magnetic slot 222 is used to accommodate two magnets 230. The rotor core 220 also includes multiple sets of second magnetic isolation slots 225. Each set of second magnetic isolation slots 225 includes two second magnetic isolation slots 225a. The two second magnetic isolation slots 225a in each set of second magnetic isolation slots 225 are distributed between the magnetic isolation bridge 223 and the two magnets 230 accommodated by the V-shaped magnetic slots 222. The area of ​​each second magnetic isolation slot 225a is larger than the area of ​​the first magnetic isolation slot 224a.

[0124] In this embodiment, since the magnetic lines of force generated by the magnet 230 always tend to follow the path of least magnetic resistance, distributing the two second magnetic isolation slots 225a in each group of second magnetic isolation slots 225 between the magnetic isolation bridge 223 and the two magnets 230 contained in the V-shaped magnetic slot 222 helps to prevent a large number of magnetic lines of force generated by the magnet 230 from forming closed loops inside the rotor core 220, thereby preventing magnetic short circuits and guiding the magnetic lines of force generated by the magnet 230 to flow to the motor stator 100, which helps to increase the output torque of the motor rotor 200.

[0125] In this embodiment, since the magnet 230 is embedded in the magnet slot 222a, when the drive motor rotates at high speed, the huge centrifugal force will throw the magnet 230 outward. Distributing the two second magnetic isolation slots 225a in each group of second magnetic isolation slots 225 between the magnetic isolation bridge 223 and the two magnets 230 contained in the V-shaped magnet slot 222 also helps to improve the mechanical strength of the rotor core 220, suppress high-speed centrifugal force, and improve the performance of the drive motor 11.

[0126] In this embodiment, the area of ​​each second magnetic isolation slot 225a is larger than the area of ​​the first magnetic isolation slot 224a. The distance between the second magnetic isolation slot 225a and the magnet 230 is small. When the motor rotor 200 rotates, the second magnetic isolation slot 225a experiences greater stress. A larger area for the second magnetic isolation slot 225a helps to better distribute stress and improves the reliability of the rotor core 220. A smaller area for the first magnetic isolation slot 224a reduces the area occupied by the magnetic isolation bridge 223, thereby improving the mechanical strength of the rotor core 220, increasing the output torque of the motor rotor 200, and enhancing the performance of the drive motor 11.

[0127] In one embodiment, such as Figure 8 As shown, the minimum distance between the second magnetic isolation groove 225a and the center hole 221 is greater than the minimum distance between the first magnetic isolation groove 224a and the center hole 221 in each group of first magnetic isolation grooves 224.

[0128] In the embodiments of this application, such as Figure 8 As shown, the minimum distance between the second magnetic isolation groove 225a and the central hole 221 is denoted as L1, and the minimum distance between the first magnetic isolation groove 224a in each group of first magnetic isolation grooves 224 and the central hole 221 is denoted as L2, where L1 > L2. Since the area of ​​the second magnetic groove 222a is larger, a larger L1 is beneficial for improving the mechanical strength of the rotor core 220, thereby improving the reliability of the drive motor 11. Because the second magnetic isolation groove 225a is distributed between the magnet 230 and the magnetic bridge 223, the stress on the second magnetic isolation groove 225a is relatively large. A smaller L2 facilitates the use of the first magnetic isolation groove 224a to disperse the stress borne by the second magnetic isolation groove 225a, which is beneficial for improving the mechanical reliability of the motor rotor 200 and extending its service life. A smaller L2 also facilitates the use of the first magnetic isolation groove 224a to reduce magnetic leakage and increase the output torque of the motor rotor 200. It also facilitates weight reduction of the rotor core 220 through the first magnetic isolation groove 224a.

[0129] Figure 9 yes Figure 8 A partial enlarged view of the M1 part of the motor rotor 200.

[0130] In one embodiment, such as Figure 8 and Figure 9 As shown, the second magnetic isolation groove 225a includes a first side 2251 and a second side 2252. The first side 2251 and the second side 2252 are distributed on both sides of the axis of symmetry of the magnetic groove 222a. The distance between the first side 2251 and the central hole 221 is less than the distance between the second side 2252 and the central hole 221. The area of ​​the first side 2251 is less than the area of ​​the second side 2252.

[0131] In this embodiment, the axis of symmetry of the magnetic groove 222a is denoted as N1. The distance between the first side 2251 and the central hole 221 is smaller than the distance between the second side 2252 and the central hole 221. A smaller area for the first side 2251 allows for a smaller protrusion of the second magnetic groove 225a towards the central hole 221, which improves the mechanical strength of the rotor core 220, thereby increasing the output torque of the motor rotor 200 and improving the performance of the drive motor 11. A larger area for the second side 2252 allows for better stress distribution, further improving the mechanical strength of the motor rotor 200 and increasing its output torque.

[0132] Among them, the axis of symmetry N1 of the magnetic steel groove 222a refers to the axis of symmetry along the length direction of the magnetic steel groove 222a. The axis of symmetry N1 divides the magnetic steel groove 222a into a first side 2251 and a second side 2252 arranged along the width direction of the magnetic steel groove 222a.

[0133] In one embodiment, such as Figure 8 and Figure 9 As shown, the area of ​​the second side 2252 protruding from the magnet 230 along the direction perpendicular to the axis of symmetry N1 of the magnet groove 222a is greater than the area of ​​the first side 2251 protruding from the magnet 230.

[0134] In this embodiment, the second side 2252 protrudes a larger area from the magnetic groove 222a along the direction perpendicular to the axis of symmetry N1 of the magnetic groove 222a. This facilitates better stress distribution on the second side 2252 of the second magnetic isolation groove 225a, which is beneficial for improving the mechanical strength of the rotor core 220. The first side 2251 protrudes a smaller area from the magnet 230 along the direction perpendicular to the axis of symmetry N1 of the magnetic groove 222a. This allows the first side 2251 to be farther from the central hole 221, which is beneficial for improving the mechanical strength of the rotor core 220 and enhancing the torque output capability of the motor rotor 200.

[0135] In one embodiment, such as Figure 8 and Figure 9 As shown, the maximum dimension of the second side 2252 along the direction perpendicular to the axis of symmetry N1 of the magnet groove 222a is greater than the maximum dimension of the first side 2251.

[0136] In the embodiments of this application, such as Figure 9 As shown, the maximum dimension of the second side 2252 along the direction perpendicular to the axis of symmetry N1 of the magnetic slot 222a is denoted as L3, and the maximum dimension of the first side 2251 is denoted as L4. L3 > L4. A smaller L4 is beneficial for the second magnetic isolation slot 225a to protrude less towards the central hole 221 along the direction perpendicular to the axis of symmetry N1 of the magnetic slot 222a, thus making the second magnetic isolation slot 225a farther from the central hole 221. This is beneficial for improving the mechanical strength of the rotor core 220 and the torque output capability of the motor rotor 200. A larger L3 results in a longer overall length of the second magnetic isolation slot 225a along the direction perpendicular to the axis of symmetry N1 of the magnetic slot 222a. This is more beneficial for dispersing stress using the second magnetic isolation slot 225a, further improving the mechanical strength of the rotor core 220 and the torque output capability of the motor rotor 200.

[0137] In one embodiment, such as Figure 9 As shown, the area of ​​the first side 2251 is smaller than the area of ​​the second side 2252, and the maximum size of the second side 2252 is greater than the maximum size of the first side 2251 along the direction of the axis of symmetry N1 perpendicular to the magnetic groove 222a.

[0138] In this embodiment, since the area of ​​the first side 2251 is large, the maximum dimension of the first side 2251 along the direction of the axis of symmetry N1 perpendicular to the magnetic groove 222a is large, which makes it easier to make the dimension of the first side 2251 along the axis of symmetry N1 of the magnetic groove 222a smaller, which makes it easier to make the dimension of the magnetic bridge 223 between the two second magnetic isolation grooves 225a larger along the circumferential C of the drive motor 11, thereby helping to improve the mechanical strength of the rotor core 220.

[0139] In one embodiment, such as Figure 8 and Figure 9 As shown, the dimension of the first side 2251 along the axis of symmetry N1 of the magnet groove 222a gradually decreases in the direction toward the central hole 221.

[0140] In this embodiment, the portion of the first side 2251 of the second magnetic isolation groove 225a near the center hole 221 can be made smaller, which helps to reduce the stress on the second magnetic isolation groove 225a, improves the mechanical strength of the rotor core 220, and thus helps to improve the output torque of the motor rotor 200.

[0141] In one embodiment, such as Figure 9 As shown, the radius of curvature of the second side 2252 of the second magnetic isolation groove 225a away from the central hole 221 is greater than the radius of curvature of the first side 2251 towards the central hole 221, and the area of ​​the second side 2252 is greater than the area of ​​the first side 2251.

[0142] In this embodiment, since the second magnetic isolation groove 225a is distributed between the magnet 230 and the magnetic isolation bridge 223, the radius of curvature of the side 2253 of the second side 2252 facing away from the central hole 221 is larger. This is beneficial because it minimizes the protrusion of the second side 2252 toward the outer periphery of the rotor core 220, resulting in a wider magnetic circuit and lower magnetic reluctance. The larger radius of curvature of the side 2253 of the second side 2252 facing away from the central hole 221 also improves the stress dispersion effect of the second side 2252.

[0143] In this embodiment, the radius of curvature of the side 2253 of the second side 2252 away from the central hole 221 is larger, which is also beneficial to make the area of ​​the second side 2252 larger. This is beneficial to the second side 2252 to better disperse stress, improve the mechanical strength of the motor rotor 200, and improve the output torque of the motor rotor 200.

[0144] In one embodiment, such as Figure 8 and Figure 9 As shown, the minimum distance between the second magnetic isolation groove 225a and the plurality of first magnetic isolation grooves 224a is less than the maximum dimension of the second magnetic isolation groove 225a along the direction perpendicular to the axis of symmetry N1 of the magnetic groove 222a.

[0145] In the embodiments of this application, such as Figure 9 As shown, the minimum distance between the second magnetic isolation slot 225a and the plurality of first magnetic isolation slots 224a is denoted as L5, and the maximum dimension of the second magnetic isolation slot 225a along the direction perpendicular to the axis of symmetry N1 of the magnetic slot 222a is denoted as L6. L5 < L6. A smaller L5 allows for a narrower portion of the magnetic isolation bridge 223 between the second magnetic isolation slot 225a and the first magnetic isolation slots 224a, which can reduce magnetic leakage between the second magnetic isolation slot 225a and the first magnetic isolation slots 224a, thus improving the output torque of the motor rotor 200 and the performance of the drive motor 11. A larger L6 allows for a larger area of ​​the second magnetic isolation slot 225a, which can better disperse stress and improve the mechanical strength of the rotor core 220, thereby improving the reliability of the motor rotor 200 and the performance of the drive motor 11.

[0146] In one embodiment, such as Figure 8 and Figure 9 As shown, the minimum dimension of the magnetic isolation bridge 223 along the circumferential direction C of the drive motor 11 is greater than the maximum dimension of the second magnetic isolation groove 225a along the axis of symmetry N1 of the magnetic groove 222a.

[0147] In the embodiments of this application, such as Figure 9 As shown, the minimum dimension of the magnetic isolation bridge 223 along the circumferential direction C of the drive motor 11 is denoted as L7, and the maximum dimension of the second magnetic isolation slot 225a along the axis of symmetry N1 of the magnet slot 222a is denoted as L8. L7 > L8, and a larger L7 can help improve the mechanical strength of the rotor core 220, improve the torque output capability of the motor rotor 200, and improve the performance of the drive motor 11. A smaller L8 can help reduce the space occupied by the second magnetic isolation slot 225a between the magnet 230 and the magnetic isolation bridge 223, making it easier to set the magnetic isolation bridge 223 larger, thereby improving the mechanical strength of the rotor core 220, improving the torque output capability of the motor rotor 200, and improving the performance of the drive motor 11.

[0148] In one embodiment, the second side 2252 of the second magnetic isolation groove 225a is away from the magnet 230 along the axis of symmetry N1 of the magnet groove 222a, and the included angle between the side of the second side 2252 of the second magnetic isolation groove 225a away from the central hole 221 and the side of the magnet groove 222a away from the central hole 221 is greater than 90 degrees and less than 180 degrees.

[0149] In the embodiments of this application, such as Figure 9As shown, the included angle between the side 2252 of the second magnetic isolation groove 225a facing away from the central hole 221 and the side of the magnetic groove 222a facing away from the central hole 221 is denoted as β. β is greater than 90 degrees and less than 180 degrees, which makes the second side 2252 of the second magnetic isolation groove 225a protrude less towards the outer periphery of the rotor core 220. This is beneficial for making the magnetic circuit wider, reducing magnetic resistance, and improving the torque output capability of the motor rotor 200. It also helps to disperse the stress borne by the second magnetic isolation groove 225a, resulting in stronger mechanical strength of the rotor core 220.

[0150] In one embodiment, such as Figure 8 and Figure 9 As shown, the second magnetic isolation groove 225a is formed by an arc-shaped sidewall surrounding the magnet 230. The second magnetic isolation groove 225a includes a first arc-shaped sidewall 2255, a second arc-shaped sidewall 2256, and a third arc-shaped sidewall 2257. The first arc-shaped sidewall 2255 and the second arc-shaped sidewall 2256 are arranged opposite each other along the direction perpendicular to the axis of symmetry N1 of the magnetic groove 222a. Along the radial direction R of the drive motor 11, the first arc-shaped sidewall 2255 is closer to the center hole 221 than the second arc-shaped sidewall 2256. The third arc-shaped sidewall 2257 is opposite to the magnet 230 along the axis of symmetry N1 of the magnetic groove 222a. The radius of curvature of the third arc-shaped sidewall 2257 of the second magnetic isolation groove 225a is greater than the radius of curvature of the first arc-shaped sidewall 2255 and greater than the radius of curvature of the second arc-shaped sidewall 2256.

[0151] In this embodiment, the third arc-shaped sidewall 2257 has a larger radius of curvature, which is beneficial for making the second magnetic isolation groove 225a smaller in size along the axis of symmetry N1 of the magnetic groove 222a. This, in turn, is beneficial for making the spacing between the two second magnetic isolation grooves 225a between the two magnets 230 accommodated in each V-shaped magnetic groove 222 larger, resulting in stronger mechanical strength of the motor rotor 200. It also facilitates the arrangement of multiple first magnetic isolation grooves 224a in each group of first magnetic isolation grooves 224 on the magnetic isolation bridge 223, reducing magnetic leakage. The larger radius of curvature of the third arc-shaped sidewall 2257 is also more conducive to stress dispersion, which is beneficial to improving mechanical strength. The smaller radii of curvature of the first arc-shaped sidewall 2255 and the second arc-shaped sidewall 2256 make the second magnetic isolation groove 225a flatter along the axis of symmetry N1 of the magnetic groove 222a. This results in a larger magnetic isolation bridge 223 between each V-shaped magnetic groove 222 along the circumferential dimension C of the drive motor 11, improving the mechanical strength of the rotor core 220.

[0152] Figure 10 This is another schematic diagram of the motor rotor 200 provided in the embodiments of this application.

[0153] In one embodiment, such as Figure 10As shown, the rotor core 220 also includes a plurality of first magnetic isolation bridges 226, which are distributed around a plurality of magnetic isolation bridges 223. Each first magnetic isolation bridge 226 is used to separate two first magnetic slots 227a in a first V-shaped magnetic slot 227. The minimum distance between the second magnetic isolation slot 225a and the first magnetic isolation bridge 226 is greater than the minimum distance between the first magnetic isolation slot 224a and the first magnetic isolation bridge 226.

[0154] In this embodiment, since the magnetic lines of force generated by the magnet 230 flow between the first magnet slot 227a and the magnet slot 222a, the minimum distance between the second magnetic isolation slot 225a and the first magnetic isolation bridge 226 is larger. This allows the second magnetic isolation slot 225a to occupy less of the magnetic circuit, resulting in lower magnetic resistance and improving the torque output capability of the motor rotor 200.

[0155] In one embodiment, such as Figure 10 As shown, the dimension of the first magnetic isolation bridge 226 along the circumferential direction C of the drive motor 11 is smaller than the dimension of the magnetic isolation bridge 223 along the circumferential direction C of the drive motor 11.

[0156] In this embodiment, since the first magnetic isolation bridge 226 is farther from the central hole 221 than the magnetic isolation bridge 223, the stress on the first magnetic isolation bridge 226 is smaller. Setting the size of the first magnetic isolation bridge 226 along the circumferential direction C of the drive motor 11 also provides sufficient mechanical strength. Furthermore, the smaller size of the first magnetic isolation bridge 226 along the circumferential direction C of the drive motor 11 helps reduce magnetic leakage and improves the torque output capability of the motor rotor 200. The smaller size of the first magnetic isolation bridge 226 along the circumferential direction C of the drive motor 11 also facilitates the arrangement of the two first magnetic slots 227a of the first V-shaped magnetic slot 227.

[0157] Figure 11a This is a local stress contour plot of the rotor core 220a provided in this application, which is a comparative example. Figure 11b This is a local stress cloud diagram of the rotor core 220 provided in this application. Figure 11a In the comparative example shown, the magnetic isolation bridge 223a is not provided with magnetic isolation grooves, and the maximum stress borne by the second magnetic isolation grooves 225b on both sides of the magnetic isolation bridge 223a exceeds 370 MPa. For example... Figure 11b As shown in this embodiment, each magnetic bridge 223 is provided with a plurality of first magnetic isolation slots 224a arranged at radial intervals R along the drive motor 11, and the maximum stress borne by the second magnetic isolation slots 225a on both sides of the magnetic bridge 223 is less than 370 MPa. That is, in this embodiment, by providing a plurality of first magnetic isolation slots 224a at radial intervals R along the drive motor 11 on the magnetic bridge 223, the stress borne by the second magnetic isolation slots 225a can be reduced, and the first magnetic isolation slots 224a can also be used to disperse part of the stress, which can improve the mechanical strength of the rotor core 220 and is beneficial to improving the torque output capability of the motor rotor 200.

[0158] Figure 12a This is a partial magnetic field line and magnetic flux density diagram of the rotor core 220a provided in this application as a comparative example. Figure 12b This is a partial magnetic field line and magnetic flux density diagram of the rotor core 220 provided in this application embodiment. In this application embodiment, multiple first magnetic isolation slots 224a are provided in each magnetic isolation bridge 223, which are arranged at radial intervals R along the drive motor 11. This can reduce magnetic leakage and help improve the output torque of the motor rotor 200. Figure 12a The comparative example shown has severe magnetic circuit saturation and high magnetic reluctance. Figure 12b The solution shown in this application can alleviate the magnetic circuit saturation of the magnetic field lines, resulting in lower magnetic resistance, which is beneficial to increasing the output torque of the motor rotor 200.

[0159] The planetary coaxial powertrain and electric vehicle provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and embodiments of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in specific embodiments and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A planetary coaxial powertrain, characterized in that, The planetary coaxial powertrain includes a drive motor, a planetary reducer, and a drive shaft. The planetary reducer receives power from the drive motor and drives the wheels of the electric vehicle via the drive shaft. The drive motor rotor includes a motor shaft and a rotor core. The motor shaft passes through a central hole in the rotor core. The drive shaft passes through the drive motor shaft, and its two ends are used to drive the planetary reducer and the wheels, respectively. The rotor core includes multiple magnetic bridges distributed around the central hole. Each magnetic bridge separates two magnetic slots in a V-shaped magnetic slot. The rotor core also includes multiple sets of first magnetic isolation slots, each set of first magnetic isolation slots includes multiple first magnetic isolation slots, and the multiple first magnetic isolation slots in each set of first magnetic isolation slots are distributed at intervals along the radial direction of the drive motor on the magnetic isolation bridge.

2. The planetary coaxial powertrain according to claim 1, characterized in that, At least one of the plurality of first magnetic isolation slots has an area greater than the area of ​​the other first magnetic isolation slots.

3. The planetary coaxial powertrain according to any one of claims 1-2, characterized in that, The area of ​​the plurality of first magnetic isolation grooves decreases sequentially along the direction away from the central hole.

4. The planetary coaxial powertrain according to any one of claims 1-3, characterized in that, The magnetic bridge includes a first segment and a second segment. Along the radial direction of the drive motor, the distance between the first segment and the central hole is less than the distance between the second segment and the central hole. Along the circumferential direction of the drive motor, the size of the first segment is greater than the size of the second segment.

5. The planetary coaxial powertrain according to claim 4, characterized in that, The first segment gradually decreases in size along the circumferential direction of the drive motor in a direction away from the central hole.

6. The planetary coaxial powertrain according to any one of claims 4-5, characterized in that, The magnetic bridge further includes a third segment. The distance between the second segment and the central hole along the radial direction of the drive motor is less than the distance between the third segment and the central hole. The size of the third segment along the circumference of the drive motor is greater than the size of the second segment.

7. The planetary coaxial powertrain according to claim 6, characterized in that, The third segment gradually increases in size along the circumferential direction of the drive motor in a direction away from the central hole.

8. The planetary coaxial powertrain according to any one of claims 1-7, characterized in that, Each of the V-shaped magnet slots is used to accommodate two magnets. The rotor core also includes multiple sets of second magnetic isolation slots. Each set of second magnetic isolation slots includes two second magnetic isolation slots. The two second magnetic isolation slots in each set of second magnetic isolation slots are distributed between the magnetic isolation bridge and the two magnets accommodated by the V-shaped magnet slots. The area of ​​each second magnetic isolation slot is larger than the area of ​​the first magnetic isolation slot.

9. The planetary coaxial powertrain according to claim 8, characterized in that, The minimum distance between the second magnetic isolation groove and the central hole is greater than the minimum distance between the first magnetic isolation groove and the central hole in each group of the first magnetic isolation grooves.

10. The planetary coaxial powertrain according to any one of claims 8-9, characterized in that, The second magnetic isolation groove includes a first side and a second side, which are distributed on both sides of the axis of symmetry of the magnetic groove. The distance between the first side and the central hole is less than the distance between the second side and the central hole, and the area of ​​the first side is less than the area of ​​the second side.

11. The planetary coaxial powertrain according to claim 10, characterized in that, The area of ​​the second side protruding from the magnet along the direction perpendicular to the axis of symmetry of the magnet groove is greater than the area of ​​the first side protruding from the magnet.

12. The planetary coaxial powertrain according to any one of claims 10-11, characterized in that, The maximum dimension of the second side along the direction perpendicular to the axis of symmetry of the magnet groove is greater than the maximum dimension of the first side.

13. The planetary coaxial powertrain according to any one of claims 8-12, characterized in that, The minimum distance between the second magnetic isolation groove and the plurality of first magnetic isolation grooves is less than the maximum dimension of the second magnetic isolation groove along the direction perpendicular to the axis of symmetry of the magnetic groove.

14. The planetary coaxial powertrain according to any one of claims 8-13, characterized in that, The minimum dimension of the magnetic isolation bridge along the circumference of the drive motor is greater than the maximum dimension of the second magnetic isolation groove along the axis of symmetry of the magnet groove.

15. An electric vehicle, characterized in that, The electric vehicle includes wheels and a planetary coaxial powertrain as described in any one of claims 1-14, the planetary coaxial powertrain being used to drive the wheels.

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