Electric machine and device using the same

Abstract

The application relates to the field of electric machines, and discloses an electric machine and a device applying the electric machine, wherein the angle of the inclined shoulder of two adjacent stator lamination groups of the electric machine is different, so as to adjust the spatial distribution of the magnetic conductance on the stator side of the two stator lamination groups, thereby adjusting the harmonic magnetic field phase of the two stator lamination groups; and the rotor slot opening width of two adjacent rotor lamination groups is set to be different, so as to adjust the spatial phase of the rotor side air gap magnetic conductance harmonic of the two rotor lamination groups. Through the different angle of the inclined shoulder of two adjacent stator lamination groups, and the different rotor slot opening width of two adjacent rotor lamination groups, the waveform phase of the electromagnetic torque of two adjacent core segments is adjusted, the waveform phase of the electromagnetic torque of two adjacent core segments is made to be 180 degrees, the electromagnetic torque pulsation of two adjacent core segments is made to be mutually cancelled, so that the pulsation value of the synthesized electromagnetic torque is minimized, and the purpose of reducing torque pulsation to inhibit noise is achieved.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more particularly to motors and equipment using motors. Background Technology

[0002] The fan motor of an air conditioner's outdoor unit is a crucial component of the air conditioning cooling system. Driven by the motor, the axial fan facilitates heat exchange between the evaporator and the outside air, dissipating heat from the evaporator into the ambient air to achieve cooling. However, to reduce production costs or meet overall design requirements, the rigidity of the motor mounting bracket is sometimes insufficient, leading to a decrease in the motor's natural frequency. Combined with manufacturing deviations in the axial fan, this causes the motor's torque pulsation frequency to coincide with its natural frequency within a certain speed range, resulting in motor resonance. Consequently, the outdoor unit resonates at a specific frequency, producing a low-frequency "humming" sound, primarily caused by the 6th harmonic of the fundamental frequency.

[0003] Related technologies propose reducing noise by blocking the noise transmission path, i.e., vibration isolation. For example, vibration-damping rubber rings or elastic metal baffles can be installed axially on the rotor core to reduce vibration and avoid low-frequency axial resonance. Furthermore, the rotor also needs additional elastic and lubricating components to reduce noise caused by axial movement. This vibration isolation structure is relatively complex, with many components, and the risk of failure of elastic and lubricating components increases over time, leading to reduced overall reliability. Another approach is to add rubber vibration damping components between the impeller and the motor. However, because the outdoor unit of the air conditioner is exposed to harsh environments such as rain, ultraviolet radiation, high and low temperatures, and thermal shock, the rubber vibration damping components are prone to aging, reducing their damping effect and thus lowering the overall reliability of the unit.

[0004] Noise reduction can be achieved by isolating vibrations to block noise transmission paths. However, the effectiveness of noise reduction depends on the reliability of the vibration isolation structure, which decreases with continuous use. Therefore, there is an urgent need for a solution that reduces noise by mitigating vibrations at the source of the noise. Summary of the Invention

[0005] The first technical problem solved by this invention is to provide a motor that can reduce noise from the perspective of vibration reduction at the excitation source.

[0006] The second technical problem solved by this invention is to provide a device that uses an electric motor, which can reduce operating noise and improve user experience.

[0007] The first technical problem mentioned above is solved by the following technical solution: Electric motor, including: A stator core includes multiple stator lamination groups stacked sequentially along the axial direction of the stator core. Each stator lamination group includes multiple stator lamination units arranged sequentially along the circumferential direction of the stator core. Each stator lamination unit includes multiple stator laminations stacked sequentially along the axial direction of the stator core. The projections of all stator laminations in the same stator lamination unit in a plane perpendicular to the axial direction of the stator core coincide. Each stator lamination includes a stator yoke, a stator tooth, and a stator crown connected sequentially from the outside to the inside. The stator tooth has tooth edge surfaces distributed opposite each other along the circumferential direction. The stator crown has two shoulder edge surfaces distributed along the circumferential direction and intersecting the two tooth edge surfaces one-to-one. The included angle between the shoulder edge surface and the tooth edge surface on the same side of the stator lamination is the shoulder angle. The shoulder angles of two adjacent stator lamination groups along the axial direction of the stator core are different. A rotor core is rotatably disposed within the stator core about its own axis. The rotor core includes multiple rotor lamination groups stacked sequentially along its own axial direction. Each rotor lamination group includes multiple rotor lamination units arranged sequentially along the circumferential direction. Each rotor lamination unit includes multiple rotor laminations stacked sequentially along the rotor core axial direction. The projections of all rotor laminations in the same rotor lamination unit in a plane perpendicular to the rotor core axial direction coincide. Between the ends of two adjacent rotor lamination units in the same rotor lamination group away from the rotor core axial direction, a gap exists along the circumferential direction to form a rotor slot. Along the axial direction of the rotor core, two adjacent rotor lamination groups satisfy the following condition: the projection of the rotor slot on one rotor lamination group in a plane perpendicular to the rotor core axial direction is located inside the projection of the rotor slot on the other rotor lamination group. The number of stator lamination groups and the number of rotor lamination groups are the same and correspond one-to-one. The dividing plane between two adjacent stator lamination groups is coplanar with the dividing plane between two corresponding adjacent rotor lamination groups.

[0008] The motor described in this invention has the following advantages compared with the prior art: The motor provided by this invention sets different shoulder angles for two adjacent stator lamination groups to adjust the spatial distribution of magnetic permeability on the stator side of the two stator lamination groups, thereby adjusting the phase of the harmonic magnetic field of the two stator lamination groups; and sets different rotor slot widths for two adjacent rotor lamination groups to adjust the spatial phase of the air gap magnetic permeability harmonics on the rotor side of the two rotor lamination groups. Therefore, this invention can adjust the waveform phase of the electromagnetic torque of two adjacent core segments by setting appropriate shoulder angles for the stator lamination groups and appropriate rotor slot widths for the rotor lamination groups, so that the waveform phases of the electromagnetic torque of the two adjacent core segments differ by 180°, thereby canceling out the electromagnetic torque pulsations of the two adjacent core segments, thus minimizing the pulsation value of the combined electromagnetic torque, achieving the purpose of reducing torque pulsation and suppressing noise.

[0009] Meanwhile, the boundary plane between two adjacent stator lamination groups is set to be coplanar with the boundary plane between two adjacent rotor lamination groups. This prevents a stator lamination group from being matched with two rotor lamination groups with different rotor slot widths. This allows the corresponding stator lamination groups and rotor lamination groups to cooperate with each other to suppress the superimposed electromagnetic torque pulsation and reduce noise from the excitation source.

[0010] In one embodiment, one of two adjacent stator lamination groups is a first stator lamination group and the other is a second stator lamination group; the shoulder angle of the first stator lamination group is α1, and the shoulder angle of the second stator lamination group is α2, where α1 > α2; One of the two adjacent rotor lamination groups is the first rotor lamination group, and the other is the second rotor lamination group; the width of the rotor slot in the first rotor lamination group along the circumferential direction is br1, and the width of the rotor slot in the second stator lamination group along the circumferential direction is br2, where br1 > br2. The first stator lamination group and the first rotor lamination group are located on one side of the dividing plane, and the second stator lamination group and the second rotor lamination group are located on the other side of the dividing plane.

[0011] In one embodiment, a portion of the plurality of stator lamination groups is the first stator lamination group, and another portion is the second stator lamination group, with the first stator lamination group and the second stator lamination group alternately distributed along the axial direction of the stator core; the shoulder angles of all the first stator lamination groups are equal, and the shoulder angles of all the second stator lamination groups are equal; And / or, a portion of the plurality of rotor lamination groups is the first rotor lamination group, and another portion is the second rotor lamination group, the first rotor lamination group and the second rotor lamination group being alternately distributed along the axial direction of the rotor core; the width of the rotor slot of all the first rotor lamination groups is equal along the circumferential direction of the rotor core, and the width of the rotor slot of all the second rotor lamination groups is equal along the circumferential direction of the rotor core.

[0012] In one embodiment, the number of stator lamination groups is odd, and the stator lamination groups on both sides of the middle stator lamination group are symmetrically distributed about the middle stator lamination group, and the rotor lamination groups on both sides of the middle rotor lamination group are symmetrically distributed about the middle rotor lamination group.

[0013] In one embodiment, there is one first stator lamination group and two second stator lamination groups, with the first stator lamination group located between the two second stator lamination groups along the axial direction of the stator core.

[0014] In one embodiment, there are two first stator lamination groups and one second stator lamination group, with the second stator lamination group located between the two first stator lamination groups along the axial direction of the stator core.

[0015] In one embodiment, 105°≤α2≤109°.

[0016] In one embodiment, 111°≤α1≤125° and α1-α2>8°.

[0017] In one embodiment, 175×π×D i1AV / (360kP)≤br1-br2≤185×π×D i1AV / (360kP), where D i1AV The value represents the average of the minimum inner diameter of the stator core and the maximum outer diameter of the rotor core, where k represents the harmonic order and P represents the number of pole pairs of the motor.

[0018] In one embodiment, P=5, Z=12, 45.9mm≤D i1AV ≤58mm; 1.82≤∣(br1-br2) / (tan(α1+α2-180°))∣≤3.01, Z represents the number of stator lamination units in one stator lamination group.

[0019] The second technical problem mentioned above is solved by the following technical solution: Devices that use electric motors include the electric motors provided in any of the above embodiments.

[0020] Compared with the prior art, the device using an electric motor described in this invention has the following advantages: The device using the aforementioned motor provided by this invention can reduce operating noise and improve user experience. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the assembly structure of the stator and rotor structures provided in an embodiment of the present invention; Figure 2 for Figure 1 A magnified view of part A in the middle; Figure 3 This is a schematic diagram of the rotor structure provided in an embodiment of the present invention; Figure 4 for Figure 3 A magnified view of part B in the middle section; Figure 5 This is a schematic diagram of the stator core structure provided in an embodiment of the present invention; Figure 6 for Figure 5 A magnified view of part C in the middle; Figure 7 An axial schematic diagram of two adjacent rotor laminations stacked together, which belong to two adjacent rotor lamination groups respectively, provided for an embodiment of the present invention; Figure 8 for Figure 7 A magnified view of part K in the middle; Figure 9 This is an axial schematic diagram of a rotor lamination assembly provided in an embodiment of the present invention; Figure 10 A side view of the rotor core provided in an embodiment of the present invention; Figure 11 An axial schematic diagram of the stator core provided in an embodiment of the present invention; Figure 12 for Figure 11 A magnified view of part P in the middle; Figure 13 This is an axial schematic diagram of a stator lamination assembly provided in an embodiment of the present invention; Figure 14 The electromagnetic torque curves obtained by finite element method for the motor using stator cores with different shoulder angles and rotor cores with different rotor slot widths provided in the embodiments of the present invention; Figure 15 and Figure 16 From respectively Figure 14 Two clusters of electromagnetic torque curves with opposite phases emerge from the cracking process; Figure 17 Electromagnetic torque curves obtained by finite element method for three types of stator cores; Figure 18 Modulation schemes combining different Ls3 and Ls4, and peak-to-peak values ​​of various electromagnetic torque curves calculated using the finite element method based on these schemes. Figure 19 For based on Figure 18 The modulation schemes that combine different Ls3 and Ls4 are used to calculate the electromagnetic torque curves of each electromagnetic torque using the finite element method.

[0022] Label Explanation: 100, Stator core; 1000, Boundary plane; 1. Stator lamination group; 1a. First stator lamination group; 1b. Second stator lamination group; 11. Stator lamination unit; 111. Stator yoke; 112. Stator tooth; 1121. Tooth edge surface; 113. Stator crown; 1131. Shoulder edge surface; 1132. Crown inner end face; 2. Rotor structure; 21. Rotor core; 211. Rotor lamination assembly; 211a. First rotor lamination assembly; 211b. Second rotor lamination assembly; 2111. Rotor lamination unit; 212. Rotor slot; 22. Rotary shaft; 23. Permanent magnet. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] This invention provides an electric motor and a device applied to the motor, which reduces noise and improves user experience by mitigating vibration at the source of excitation. It should be noted that the device using the motor can be an outdoor unit of an air conditioner, or other devices that require a motor, which will not be listed here.

[0028] like Figures 1 to 13 As shown, the motor includes a stator structure and a rotor structure 2. The stator structure includes a stator core 100 and a stator winding wound around the stator core 100. The rotor structure 2 includes a rotor core 21, a permanent magnet 23 installed in the stator core 100, and a rotating shaft 22 that axially passes through the rotor core 21 and is installed in the rotor core 21. The rotor core 21 is rotatably inserted into the stator core 100 around its own axis.

[0029] The stator core 100 includes a plurality of stator lamination groups 1 stacked sequentially along the axial direction of the stator core 100. Each stator lamination group 1 includes a plurality of stator lamination units 11 arranged sequentially along the circumferential direction of the stator core 100. Each stator lamination unit 11 includes a plurality of stator laminations stacked sequentially along the axial direction of the stator core 100. The projections of all stator laminations in the same stator lamination unit 11 in a plane perpendicular to the axial direction of the stator core 100 coincide. Each stator lamination includes a stator yoke 11 connected sequentially from the outside to the inside. 1. Stator teeth 112 and stator crown 113. The stator teeth 112 have tooth edge surfaces 1121 distributed circumferentially. The stator crown 113 has two circumferentially distributed shoulder edge surfaces 1131 that intersect the two tooth edge surfaces 1121 one-to-one. The included angle between the shoulder edge surface 1131 and the tooth edge surface 1121 on the same side of the stator lamination is the shoulder angle. The shoulder angles of two adjacent stator lamination groups 1 along the axial direction of the stator core 100 are different. It should be understood that: Figure 11-12 As shown, projection coincidence means that the outlines of the projections of all stator laminations in the same stator lamination unit 11 in a plane perpendicular to the axial direction of the stator core 100 are consistent and completely coincident.

[0030] The rotor core 21 is rotatably disposed within the stator core 100 about its own axis. The rotor core 21 includes a plurality of rotor lamination groups 211 stacked sequentially along its own axial direction. The rotor lamination group 211 includes a plurality of rotor lamination units 2111 arranged sequentially along the circumferential direction. Each rotor lamination unit 2111 includes a plurality of rotor laminations stacked sequentially along the axial direction of the rotor core 21. The projections of all rotor laminations in the same rotor lamination unit 2111 coincide in a plane perpendicular to the axial direction of the rotor core 21. Between the ends of two adjacent rotor lamination units 2111 of the same rotor lamination group 211 that are away from the axial direction of the rotor core 21, there is a gap in the circumferential direction to form a rotor slot 212. Along the axial direction of the rotor core 21, two adjacent rotor lamination groups 211 satisfy the following condition: the projection of the rotor slot 212 on one rotor lamination group 211 in a plane perpendicular to the axial direction of the rotor core 21 is located inside the projection of the rotor slot 212 on the other rotor lamination group 211. It is important to understand that: such as Figure 7 As shown, projection coincidence means that the outlines of the projections of all rotor laminations in the same rotor lamination unit 2111 in a plane perpendicular to the axial direction of the rotor core 21 are consistent and completely coincident.

[0031] The stator lamination group 1 and the rotor lamination group 211 are the same in number and correspond one-to-one. The dividing plane 1000 between two adjacent stator lamination groups 1 is coplanar with the dividing plane 1000 between two corresponding adjacent rotor lamination groups 211. It should be noted that the planes containing the axial end faces of two adjacent stator lamination groups 1 that are opposite each other along the axial direction of the stator core 100 are located on the same plane, which is the dividing plane 1000.

[0032] The presence of rotor slot 212 and stator slot 100 inevitably introduces magnetic harmonics. Studies have found that the low-frequency "humming" sound during motor operation is mainly caused by the 6th fundamental frequency harmonic.

[0033] In the actual operation of the motor, due to the conventional Y-connection, the third and multiples of the third harmonics in the line back EMF cancel each other out. Therefore, the fifth, seventh, and eleventh harmonics are the main harmonic components. The interaction of the fifth and seventh harmonics with the fundamental current generates a sixth-harmonic torque pulsation. Simultaneously, the armature winding powered by the controller contains fifth and seventh harmonic currents, which, in turn, generate a sixth-harmonic torque pulsation with the fundamental back EMF. Furthermore, the opening of the rotor slot 212 also introduces harmonics. Although harmonics are usually reduced by decreasing the width of the rotor slot 212, this reduction leads to increased leakage flux, resulting in a decrease in the effective magnetic flux of the physical air gap and stator windings, thereby reducing the motor's power density.

[0034] For ease of description, the motor core includes a stator core 100 and a rotor core 21. The rotor core 21 has multiple rotor lamination groups 211, and the stator core 100 has multiple stator lamination groups 1 that correspond one-to-one with the multiple rotor lamination groups 211. The motor core is divided into multiple core segments along the axial direction. Each core segment includes a stator lamination group 1 and a corresponding rotor lamination group 211.

[0035] The width of the rotor slot 212 directly changes the circumferential ratio of the rotor teeth to the rotor slot 212 and the degree of edge magnetic flux diffusion. The change in the width of the rotor slot 212 will cause the peak and valley values ​​of the air gap magnetic permeability in the circumferential direction of the rotor core 21 to shift along the circumferential direction as a whole, and the spatial initial phase of the rotor magnetic permeability harmonics and the amplitude of each harmonic will change synchronously.

[0036] When the motor uses a single rotor lamination group 211 with a single rotor slot 212 width, the rotor magnetic permeation harmonic phase is fixed, and the harmonic torque generated by the motor has a fixed initial phase. When the shoulder angle is fixed, the stator magnetic permeation harmonics remain unchanged, but the width of the rotor slot 212 changes, causing a spatial phase shift in the rotor magnetic permeation harmonics. This results in an overall phase shift in the electromagnetic torque pulsation waveform of the motor, meaning the phase of the electromagnetic torque pulsation waveform changes. Therefore, the rotor core 21 can use multiple rotor lamination groups 211, with different widths of the rotor slots 212 between adjacent rotor lamination groups 211. This causes the rotor magnetic permeation harmonics of adjacent rotor lamination groups 211 to be staggered by a certain electrical angle, thereby creating a phase difference in the harmonic torque waveform.

[0037] The change in the shoulder angle of the stator core 100 directly alters the outer contour of the tooth shoe and the magnetic flux diffusion range at the edge of the tooth tip, reshaping the periodically undulating air gap magnetic permeability curve along the circumferential direction.

[0038] For a motor with a stator lamination group 1 and all stator laminations having the same shoulder angle, the rotor permanent magnet magnetic field harmonic phase is fixed under the premise that the width of the rotor slot 212 is fixed and the shoulder angle is fixed.

[0039] With the width of the rotor slot 212 fixed, changing the shoulder angle of the stator core 100 alters the stator tooth profile and the area of ​​the magnetically conductive region. This causes a spatial phase shift in the magnetic harmonics of the stator core 100 along the circumferential direction, resulting in a change in the phase of the overall electromagnetic torque pulsation waveform of the motor. Therefore, the stator core 100 can be constructed using multiple stator lamination groups 1, with different shoulder angles between adjacent groups. This allows the magnetic harmonics on the stator side of adjacent core segments to be offset by a certain electrical angle, resulting in a corresponding phase shift in the harmonic torque waveform.

[0040] Therefore, the motor provided in this embodiment adjusts the spatial distribution of magnetic permeability on the stator side of the two stator lamination groups 1 by setting different shoulder angles for adjacent stator lamination groups 1, thereby adjusting the phase of the harmonic magnetic field of the two stator lamination groups 1; and sets different widths for the rotor slots 212 of adjacent rotor lamination groups 211 to adjust the spatial phase of the air gap magnetic permeability harmonics on the rotor side of the two rotor lamination groups 211. By adjusting the different shoulder angles of the two adjacent stator lamination groups 1, combined with the different widths of the rotor slots 212 of the two adjacent rotor lamination groups 211, the waveform phase of the electromagnetic torque of the two adjacent iron core segments is adjusted so that the waveform phase of the electromagnetic torque of the two adjacent iron core segments differs by 180°, thereby making the electromagnetic torque pulsations of the two adjacent iron core segments cancel each other out, thus minimizing the pulsation value of the combined electromagnetic torque, achieving the purpose of reducing torque pulsation and suppressing noise.

[0041] The boundary plane 1000 between two adjacent stator lamination groups 1 provided in this embodiment of the invention is coplanar with the boundary plane 1000 between two adjacent rotor lamination groups 211, so that the phase difference of the electromagnetic torque waveform of the two adjacent core segments is 180°. If the boundary plane 1000 between two adjacent stator lamination groups 1 is not coplanar with the boundary plane 1000 between two adjacent rotor lamination groups 211, it is possible that one stator lamination group 1 will cooperate with two rotor lamination groups 211 with different widths of rotor slot 212, or one rotor lamination group 211 will cooperate with two stator lamination groups 1 with different shoulder angles. This will cause the difference between the phase difference of the electromagnetic torque waveform of the two adjacent core segments and 180° to increase, thereby increasing the electromagnetic torque pulsation and the motor operating noise. Therefore, the dividing plane 1000 between two adjacent stator lamination groups 1 is made coplanar with the dividing plane 1000 between the corresponding two adjacent rotor lamination groups 211, so that the electromagnetic torque obtained after the waveforms of the electromagnetic torque of the two adjacent iron core segments are superimposed is smaller.

[0042] Therefore, the dividing plane 1000 between two adjacent stator lamination groups 1 is made coplanar with the dividing plane 1000 between two corresponding adjacent rotor lamination groups 211, so that the stator lamination group 1 and rotor lamination group 211 are matched with each other to reduce the torque pulsation of the sixth harmonic caused by the sixth fundamental frequency while ensuring that the power density of the motor meets the requirements.

[0043] Specifically, the rotor lamination includes a lamination body. External magnetic bridges protrude from both opposite side walls of the lamination body along the circumferential direction. The external magnetic bridges are located at the end of the lamination body away from the axis of the rotor core 21. Two external magnetic bridges between two adjacent rotor laminations are spaced apart along the circumferential direction to form rotor sub-slots. The rotor sub-slots on different rotor laminations in the same rotor lamination group 211 are connected one-to-one to form a rotor slot 212. The rotor slots 212 are arranged parallel to each other along the opposite side walls of the rotor core 21 circumferentially. In a projection plane perpendicular to the axis of the rotor core 21, with the projection of the axis of the rotor core 21 as the center, the central angle corresponding to the projection of each rotor lamination has an angle bisector. Any rotor lamination group 211 is symmetrically arranged about the corresponding angle bisector. Therefore, the width of the rotor slot 212 is the distance between the opposite side walls of the rotor slot 212 along the circumferential direction of the rotor core 21. This ensures that all rotor slots 212 of the same stator lamination group 1 have equal widths along the circumference of the rotor core 21, which helps reduce processing difficulty. It should be noted that, in some other embodiments, the two side walls of the rotor slots 212 arranged opposite each other along the circumference of the rotor core 21 can also be distributed at an included angle.

[0044] It should be noted that all the sloping shoulder angles in the same stator lamination group 1 are the same.

[0045] In some embodiments, such as Figures 1 to 13 As shown, one of two adjacent stator lamination groups 1 is the first stator lamination group 1a, and the other is the second stator lamination group 1b; the shoulder angle of the first stator lamination group 1a is α1, and the shoulder angle of the second stator lamination group 1b is α2, α1 > α2; one of two adjacent rotor lamination groups 211 is the first rotor lamination group 211a, and the other is the second rotor lamination group 211b; the width of the rotor slot 212 of the first rotor lamination group 211a along the circumferential direction is br1, and the width of the rotor slot 212 of the second stator lamination group 1b along the circumferential direction is br2, br1 > br2; the two adjacent stator lamination groups 1 and the corresponding two adjacent rotor lamination groups 211 satisfy the following: the first stator lamination group 1a and the first rotor lamination group 211a are located on one side of the dividing plane 1000, and the second stator lamination group 1b and the second rotor lamination group 211b are located on the other side of the dividing plane 1000.

[0046] For a motor where all rotor slots 212 have the same width, as the width of the rotor slots 212 increases, the leakage flux in the outer magnetic bridge region increases, the effective magnetic flux in the physical air gap decreases, and the average electromagnetic torque under the same current decreases slightly; the short-term maximum output power of the motor decreases slightly, and the peak power density decreases slightly. Under the premise that the stator shoulder angle is within a certain range, the larger the stator shoulder angle, the less likely the stator tooth crown region is to become magnetically saturated, and the higher the power density of the motor; when the shoulder angle exceeds a certain value, the power density of the motor will begin to decrease.

[0047] Arranging the first stator lamination group 1a with a larger shoulder angle and the first rotor lamination group 211a with a wider rotor slot 212 on one side of the dividing plane 1000, and arranging the second stator lamination group 1b with a smaller shoulder angle and the second rotor lamination group 211b with a narrower rotor slot 212 on the other side of the dividing plane 1000, can avoid excessive local leakage flux, reduce the risk of local magnetic saturation, and help ensure that the power density of the motor meets the requirements.

[0048] In some embodiments, such as Figures 1 to 13 As shown, a portion of the multiple stator lamination groups 1 is the first stator lamination group 1a, and the other portion is the second stator lamination group 1b. The first stator lamination groups 1a and the second stator lamination groups 1b are alternately distributed along the axial direction of the stator core 100. The shoulder angles of all first stator lamination groups 1a are equal, and the shoulder angles of all second stator lamination groups 1b are equal. In other words, based on the size of the shoulder angle, the stator lamination groups 1 are divided into two categories: the first stator lamination group 1a and the second stator lamination group 1b. There are no stator lamination groups 1 with other shoulder angles, which reduces the structural complexity of the entire motor and lowers the processing cost.

[0049] In some embodiments, a portion of the plurality of rotor lamination groups 211 is a first rotor lamination group 211a, and the other portion is a second rotor lamination group 211b. The first rotor lamination groups 211a and the second rotor lamination groups 211b are alternately distributed along the axial direction of the rotor core 21. The rotor slots 212 of all first rotor lamination groups 211a have equal widths along the circumference of the rotor core 21, and the rotor slots 212 of all second rotor lamination groups 211b have equal widths along the circumference of the rotor core 21. In other words, based on the width of the rotor slots 212 of the rotor lamination groups 211, there are two types of rotor lamination groups 211: one is the first rotor lamination group 211a, and the other is the second rotor lamination group 211b. There are no rotor lamination groups 211 with other slot widths. That is, the rotor core 21 only has rotor lamination groups 211 with two slot widths, which helps to reduce the structural complexity of the entire motor and reduce processing costs.

[0050] It should be noted that the rotor lamination group 211 can also be divided into three, four, or five categories with different widths of rotor slots 212. The number of types of rotor lamination group 211 is the same as the number of types of stator lamination group 1.

[0051] In some embodiments, such as Figures 1 to 13As shown, the number of stator lamination groups 1 is odd. The stator lamination groups 1 on both sides of the middle stator lamination group 1 are symmetrically distributed about the middle stator lamination group 1, and the rotor lamination groups 211 on both sides of the middle rotor lamination group 211 are symmetrically distributed about the middle rotor lamination group 211. This arrangement ensures that the stator core 100 on both sides of the middle stator lamination group 1 and the rotor core 21 on both sides of the middle rotor lamination group 211 have the same structure, avoiding the problems of axial additional harmonics and uneven axial leakage magnetic flux caused by asymmetry; at the same time, it avoids torsional vibration and segmented vibration caused by the inconsistent distribution of electromagnetic forces on both sides of the middle stator lamination group 1 and the middle rotor lamination group 211.

[0052] For example, the number of stator lamination groups 1 is three. It should be noted that, provided that the number of rotor lamination groups 211 is the same as the number of stator lamination groups 1, the number of stator lamination groups 1 can also be five, seven, etc., and the number of stator lamination groups 1 can also be an even number, such as two, four, etc.

[0053] For example, there is one first stator lamination group 1a and two second stator lamination groups 1b. The first stator lamination group 1a is located between the two second stator lamination groups 1b along the axial direction of the stator core 100. Correspondingly, there is one first rotor lamination group 211a and two second rotor lamination groups 211b. The first rotor lamination group 211a is arranged between the two second rotor lamination groups 211b along the axial direction of the rotor core 21.

[0054] In other embodiments, two first stator lamination groups 1a and one second stator lamination group 1b may be provided, with the second stator lamination group 1b arranged between the two first stator lamination groups 1a along the axial direction of the stator core 100. Correspondingly, one second rotor lamination group 211b is provided, and two first rotor lamination groups 211a are provided, with the second rotor lamination group 211b arranged between the two first rotor lamination groups 211a along the axial direction of the rotor core 21.

[0055] In some embodiments, the axial length of the rotor core 21 is Lr, and the axial length of the stator core 100 is Ls, where Lr > Ls. One axial end of the rotor core 21 extends from one axial end of the stator core 100, and the other axial end of the rotor core 21 extends from the other axial end of the stator core 100. This arrangement ensures that both axial ends of the rotor core 21 extend from both axial ends of the stator core 100 with equal extension lengths.

[0056] When the lengths of the rotor core 21 extending from the axial ends of the stator core 100 are unequal, the stator magnetic field and the rotor magnetic field of the motor couple, causing the rotor core 21 to be subjected to an unbalanced axial tensile force. When this motor is applied to an outdoor air conditioning unit, the fan of the outdoor unit is an axial flow fan, and the impeller of the axial flow fan is installed at the output end of the rotating shaft 22. Considering the influence of the fan's machining error and the machining error of the rotor core 21, the rotor core 21 is subjected to a periodically fluctuating axial force, which in turn increases the noise during motor operation. Therefore, making the axial length of the rotor core 21 greater than the axial length of the stator core 100, and making the lengths of the rotor core 21 extending from the axial ends of the stator core 100 equal, can not only reduce the noise during motor operation, but also increase the back electromotive force by utilizing the magnetic field end effect.

[0057] Provided that Lr > Ls, the difference between Lr and Ls is determined according to the actual design requirements, usually 1.5mm ≤ Lr - Ls ≤ 2.5mm.

[0058] In some embodiments, the axial stack thickness of the first stator lamination group 1a is Ls1, and the axial stack thickness of the second stator lamination group 1b is Ls2, |Ls1-Ls2|≥1mm. Since the thickness of a single stator lamination is generally 0.5mm, based on this practical factor, in order to make the stack thickness of two adjacent stator lamination groups 1 different, the stack thickness difference between two adjacent stator lamination groups 1 is required to be greater than or equal to 1mm.

[0059] It should be noted that, since the boundary plane 1000 between two adjacent stator lamination groups 1 is coplanar with the boundary plane 1000 between two corresponding adjacent rotor lamination groups 211, the stack thickness of the rotor lamination group 211 between the two rotor lamination groups 211 located at both ends of the rotor core 21 is equal to the stack thickness of the corresponding stator lamination group 1. Since the number of stator lamination groups 1 is odd and equal to the number of rotor lamination groups 211, and the rotor lamination groups 211 on both sides of the middle rotor lamination group 211 are symmetrically arranged, the stack thickness of the two rotor lamination groups 211 located at both ends of the rotor core 21 is equal. Furthermore, considering 1.5mm ≤ Lr-Ls ≤ 2.5mm, only Lr-Ls and the stack thickness of a single stator lamination group 1 need to be determined to determine the stack thickness of the rotor lamination groups 211 located at both ends of the rotor core 21.

[0060] In some embodiments, such as Figures 1 to 13As shown, 105°≤α2≤109°. Within the angle range of α2 greater than or equal to 105° and less than or equal to 109°, magnetic saturation will occur in the stator crown region 113. When local magnetic saturation occurs in the stator core 100, the permeability of the stator core 100 will be nonlinear, thereby changing the frequency of electromagnetic torque pulsation to achieve frequency shifting. This causes the frequency of electromagnetic torque pulsation of the motor to deviate from the natural frequency of the motor, thereby reducing the 6th harmonic torque pulsation caused by the 6th fundamental harmonic.

[0061] It should be noted that α2 can be any angle within the range of 105° to 109°, such as 105°, 105.5°, 106°, 106.5°, 107°, 107.5°, 108°, 108.5°, and 109°.

[0062] In some embodiments, such as Figures 1 to 13 As shown, 111°≤α1≤125° and α1-α2>8°. After the sloping shoulder angle exceeds a certain range, the larger the sloping shoulder angle, the smaller the leakage flux in the stator crown region 113, making it less prone to magnetic saturation, and simultaneously increasing the motor's power density. Since 105°≤α2≤109°, although the frequency shifting noise reduction is achieved, the motor's power density is reduced. When the difference between α1 and α2 is less than or equal to 8°, the difference is too small, causing α1 to also fall within the region of the stator crown 113 where magnetic saturation is likely to occur. This means that setting α1 also reduces the motor's power density, resulting in a lower power density due to the combined effects of α1 and α2. Therefore, α1-α2≥8° is required, utilizing 105°≤α2≤109° to achieve frequency shifting noise reduction; and combined with 111°≤α1≤125° and α1-α2>8°, the influence of α2 on the motor's power density is reduced, ensuring the motor's power density meets the requirements.

[0063] Instantaneous electromagnetic torque T of the motor e (t) = T0 + ∑Tkcos(kωt + φTk), where T0 represents the average electromagnetic torque of the motor, k represents the harmonic order, ωt represents the real-time electrical angle varying with time, and φTk represents the initial phase of the kth harmonic. Based on the above formula for instantaneous electromagnetic torque and the idea of ​​eliminating electromagnetic torque pulsation, when the waveform phases of the electromagnetic torques of two adjacent iron core segments are opposite, the purpose of eliminating the 6th harmonic torque component can be achieved.

[0064] The initial phase of the electromagnetic torque of the k-th harmonic generated by the coupling of the magnetic permeability harmonics caused by the opening of stator slots and rotor slots 212 with the current in the stator windings is denoted as φTk. The average diameter of the physical air gap between the stator core 100 and the rotor core 21 is D. i1AV D i1AVIt is equal to the average of the minimum inner diameter of the stator core 100 and the maximum outer diameter of the rotor core 21. The average diameter is D. i1AV The circumference of the physical air gap is πD i1AV The average diameter is D i1AV The mechanical angle corresponding to the unit arc length of the physical air gap is 360° / πD i1AV Converted to radians 2π / πD i1AV =2 / D i1AV The motor has P pole pairs. According to basic electromagnetic principles, rotor magnetic harmonics are introduced due to the rotor slotting effect. FFT decomposition of these harmonics yields an initial phase proportional to the number of poles, the width of rotor slot 212, and the average radius of the air gap. The electrical angle corresponding to rotor slot 212 is P × 2br / D. i1AV Similarly, due to the influence of the stator slots, stator magnetic permeability harmonics are introduced. The initial phase of the harmonics obtained after FFT is proportional to the product of the number of slots, the width of the stator slots, and the air gap radius. The stator core 100 has Z stator slots distributed sequentially along its circumference. The number of stator slots is equal to the number of stator lamination units 11 in a stator lamination group 1. The total phase contribution of the magnetic permeability harmonics of the stator core 100 formed by the Z stator slots is Z×bs / D. i1AV The spatial phase difference Δθ caused by the magnetic permeability harmonics induced by opening the stator slot and rotor slot 212 is (2P×br / D). i1AV -Z×bs / D i1AV ) × 180° / π. For the kth spatial harmonic, the spatial phase increases exponentially with the harmonic order, and the spatial phase of the kth harmonic is equal to k × Δθ.

[0065] The real-time electrical phase of the back EMF corresponding to the current in the stator winding is φ. i The electromagnetic torque of a permanent magnet motor has a fixed phase offset of -π / 2 relative to the back electromotive force. This is the basic phase relationship of armature coupling, which will not be described in detail here.

[0066] By coupling the magnetic permeability harmonics induced by opening the stator slot and rotor slot 212 with the current in the stator winding, the initial phase φTk=k(2P×br / D) of the k-th harmonic electromagnetic torque is obtained. i1AV -Z×bs / D i1AV )×180° / π+φ i -π / 2.

[0067] It should be noted that, along the radial direction of the stator core 100, the end face of the stator crown 113 near the axis of the stator core 100 is the inner end face 1132 of the crown. The inner end face 1132 of the crown may not necessarily lie entirely on the same arc surface. The minimum inner diameter of the stator core 100 refers to the minimum distance between the inner end face 1132 of the crown and the axis of the stator core 100 along the radial direction of the stator core 100. Similarly, the outer circumferential surface of the rotor core 21 may not necessarily lie entirely on the same arc surface. Therefore, the maximum outer diameter of the rotor core 21 refers to the maximum distance between the outer circumferential surface of the rotor core 21 and the axis of the rotor core 21 along the radial direction of the rotor core 21.

[0068] Based on the above formula, it can be seen that the width br of the rotor slot 212 affects the initial phase of the harmonic torque.

[0069] For a motor where the stator core 100 uses two stator lamination groups 1 with different shoulder angles, and the rotor core 21 uses two rotor lamination groups 211 with different rotor slot widths 212, when the electrical angle Δφ = |φTk1 - φTk2| = 180°, the waveform phases of the electromagnetic torques of two adjacent core segments are opposite. Here, φTk1 is the initial phase of the electromagnetic torque of one core segment, and φTk2 is the initial phase of the electromagnetic torque of the other core segment. Considering manufacturing processes, the width of the rotor slot 212 is discrete. Based on engineering experience, it is determined that Δφ within the range of 175° to 185° is sufficient to fundamentally modulate and cancel out the pulsations of the electromagnetic torques of the two core segments.

[0070] It should be noted that the electrical angle is the angular reference for the motor's magnetic field, windings, harmonics, and torque pulsation, with the spatial angle corresponding to a pair of N and S magnetic poles constituting one complete electrical cycle (360°). The initial phase of the motor refers to the electrical angle corresponding to the motor's torque waveform at a selected time zero point or rotor position zero point.

[0071] Based on the above formula φTk=k[2P×br / D i1av -Z×bs / D i1av ]+φ i Given -π / 2, Δφ=∣φTk1-φTk2∣, and 175°≤Δφ≤185°, we can calculate 175×π×D. i1AV / (360kP)≤br1-br2≤185×π×D i1AV / (360kP), by limiting the difference between br1 and br2, the electromagnetic torque waveforms of the two adjacent iron core segments that cause 6 times frequency torque pulsation are out of phase when the motor is working, so as to suppress the 6 times frequency torque pulsation and reduce the noise of the motor.

[0072] For example, P=5, Z=12, 45.9mm≤D i1AV≤58mm. Under the following conditions, P=5, Z=12, the effective current value of the stator winding is I1, 0.05A≤I1≤0.15A, the maximum surface magnetic density of rotor structure 2 is Br, 1500Gs≤Br≤1800Gs, D i1AV Select one of the values ​​within the range of 45.9mm to 58mm, and select a pre-selected known value for bs, based on 175×π×D. i1AV / (360kP)≤br1-br2≤185×π×D i1AV Given this premise (360kP), by changing different D... i1AV A family of electromagnetic torque curves is obtained from br1, br2, α1, and α2. Electromagnetic torque curves with opposite phases and similar peak-to-peak values ​​are selected from this family. Based on the selected electromagnetic torque curves, D... i1AV D is obtained by fitting br1, br2, α1, and α2. i1AV The relationship between br1, br2, α1, and α2 is established, and based on 45.9mm≤D i1AV The calculation for ≤58mm yields 1.82≤∣(br1-br2) / (tan(α1+α2-180°))∣≤3.01.

[0073] When the condition 1.82≤∣(br1-br2) / (tan(α1+α2-180°))∣≤3.01 is met, the initial phase difference of the electromagnetic torques of the two iron core segments that cause the sixth harmonic torque pulsation can be made to be about 180°, and the peak-to-peak difference of the electromagnetic torques of the two iron core segments can be small, so as to achieve the purpose of suppressing the sixth harmonic torque pulsation.

[0074] It should be noted that |(br1-br2) / (tan(α1+α2-180°))| can be any value within the range of 1.82 or greater and 3.01 or less, such as any value among 1.82mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm, and 3.01mm.

[0075] Figure 14 For motors using stator cores 100 with different shoulder angles and rotor cores 21 with different rotor slot widths 212, a set of electromagnetic torque curves calculated using the finite element method is presented. Figure 14 Fission Figure 15 The modulation waveform cluster 1 shown represents a motor using stator cores 100 with different shoulder angles; and Figure 16 The modulation waveform cluster 2 shows the motors using rotor cores 21 with different widths of rotor slots 212. See also... Figure 15 and Figure 16 As shown, the phases of modulation wave curve cluster 1 and modulation wave curve cluster 2 are basically opposite. It should be noted that, according to... Figure 14 The electromagnetic torque curve cluster was cracked to obtain Figure 15 Modulation wave curve cluster 1 and Figure 16 Modulation curve cluster 2 refers to the selected Figure 14 The two modulation wave curves with opposite phases are shown in the figure. It can be seen that the shoulder angle and the width of the rotor slot 212 affect the electromagnetic torque pulsation. By using stator cores 100 with at least two shoulder angles and rotor cores 21 with at least two widths of rotor slots 212, the electromagnetic torque waveforms of adjacent core segments can be made to have opposite phases.

[0076] like Figure 17 As shown, assuming the inner diameter of the stator core 100 is 50.9 mm, for a motor with one stator lamination group 1 and using the first stator lamination group 1a, α1 = 121°, br1 = 3.7 mm, the electromagnetic torque curve calculated using the finite element method is denoted as modulation wave 1. For a motor with one stator lamination group 1 and using the second stator lamination group 1b, α2 = 105°, br2 = 1.1 mm, the electromagnetic torque curve calculated using the finite element method is denoted as modulation wave 2. For a stator core 100 with three stator lamination groups 1, using one first stator lamination group 1a and two second stator lamination groups 1b, α1=121°, br1=3.7mm, α2=105°, br2=1.1mm, when the stack thickness Ls1 of the first stator lamination group 1a is equal to the sum of the stack thickness Ls2 of all the second stator lamination groups 1b, the electromagnetic torque curve of the motor is obtained by synthesizing modulation wave 1 and modulation wave 2, denoted as synthesized wave 1. From Figure 17 It can be seen that the phases of modulation wave 1 and modulation wave 2 are opposite, and the peak-to-peak values ​​of modulation wave 1 and modulation wave 2 differ significantly. The peak-to-peak value of modulation wave 1 is approximately 6.98 m·Nm, while that of modulation wave 2 is approximately 6.11 m·Nm. For a motor using stator core 100 with two different shoulder angles and rotor core 21 with two different widths of rotor slots 212, the peak-to-peak value of the composite wave 1 is 2.05 m·Nm, a decrease of approximately 66.4%, which can significantly reduce the 6th harmonic torque pulsation. Therefore, it can be seen that using stator core 100 with two different shoulder angles and rotor core 21 with two different widths of rotor slots 212 in combination can make the waveform phases of the electromagnetic torque pulsations of the two core segments approximately 180° apart, thus reducing the 6th harmonic torque pulsation.

[0077] The inventors discovered that when the phase difference between modulation wave 1 and modulation wave 2 is about 180°, but the peak-to-peak value difference is large, the slot width bs1 of the first stator lamination group 1a and the slot width bs2 of the second stator lamination group 1b can be modulated to reduce the difference between the peak values ​​of modulation wave 1 and modulation wave 2, thereby reducing the peak-to-peak value of the synthesized wave.

[0078] When the slot width bs1 of the first stator lamination group 1a is equal to the slot width bs2 of the second stator lamination group 1b, the peak-to-peak value cannot be kept low. Taking a motor with two types of core segments as an example, where the first type of core segment includes at least one first stator lamination group 1a and the second type of core segment includes at least one second stator lamination group 1b, theoretically, the peak-to-peak value of the synthesized wave can be minimized or even reduced to zero when Tpek1×Ls3=Tpek2×Ls4. Here, Tpek1 represents the peak-to-peak torque value of the first type of core segment, Ls3 represents the stack thickness of all first stator lamination groups 1a in the first type of core segment, Tpek2 represents the peak-to-peak torque value of the second type of core segment, and Ls4 represents the sum of the stack thicknesses of all second stator lamination groups 1b in the second type of core segment.

[0079] Taking the following motor as an example, the motor has two types of core segments: a first core segment and a second core segment. The stator core 100 includes two second stator lamination groups 1b and a first stator lamination group 1a located between the two second stator lamination groups 1b along the axial direction of the stator core 100. The rotor core 21 includes two second rotor lamination groups 211b and a first rotor lamination group 211a located between the two second rotor lamination groups 211b along the axial direction of the rotor core 21. The thickness of the first rotor lamination group 211a is equal to the thickness of the first stator lamination group 1a. The thicknesses of the two second rotor lamination groups 211b and the two second stator lamination groups 1b are equal. The first stator lamination group 1a and the first rotor lamination group 211a form the first core segment, and the second stator lamination group 1b and the second rotor lamination group 211b form the second core segment. This motor has one first core segment and two second core segments. Assuming Ls = Ls3 + Ls4 = 15mm, where Ls3 equals the stack thickness Ls1 of one first stator lamination group 1a, and Ls4 equals the sum of the stack thickness Ls2 of two second stator lamination groups 1b, i.e., Ls4 = 2Ls2. The actual Ls1 and Ls2 are discrete values, mainly depending on the thickness of a single stator lamination. The thickness of a stator lamination, i.e., its axial thickness, is 0.5mm. Under the premise that the inner diameter of the stator core 100 is 50.9mm, P = 5, Z = 12, α1 = 121°, br1 = 2.9mm, α2 = 109°, and br2 = 2.1mm, referencing... Figure 18 As shown, modulation schemes based on different combinations of Ls3 and Ls4 are presented, and their respective electromagnetic torque curves are calculated using the finite element method. See details in [link to documentation]. Figure 19 The curves of synthetic waves 1 to 4 and synthetic wave 8. Based on Figure 19 The curve of the modulated wave shown can be calculated to obtain... Figure 18 The peak-to-peak torque of modulation wave 1 is 8.12 m·Nm, and the peak-to-peak torque of modulation wave 2 is 20.29 m·Nm. Figure 18 The peak-to-peak torque values ​​of the other composite wave curves shown are also included. (Reference) Figure 18 It is evident that the peak-to-peak value of the synthesized wave reaches its minimum when Ls3 = 0.2 × Ls = 3 mm and Ls4 = 0.8 × Ls = 12 mm. Therefore, when Ls3 = Ls1 = 3 mm, and the stack thickness of a single second stator lamination group 1b is Ls2 = Ls4 / 2, and Ls2 = 6 mm, the peak-to-peak value of the synthesized wave is minimized. Therefore, when the phase difference and peak-to-peak value difference between modulation waves 1 and 2 are significant, the stack thickness Ls1 of a single first stator lamination group 1a and the stack thickness Ls2 of a single second stator lamination group 1b can be modulated to ensure that the phase difference between modulation waves 1 and 2 is as close to 180° as possible, and to reduce the difference between the peak-to-peak values ​​of modulation waves 1 and 2.

[0080] In some embodiments, such as Figure 1 and Figure 12 As shown, the inner end face 1132 of the crown is an arc surface coaxial with the stator core 100, or includes a first arc surface coaxial with the stator core 100 and a second arc surface eccentric to the axis of the stator core 100, with the first and second arc surfaces connected; or includes an arc surface coaxial with the stator core 100 and a plane parallel to the axis of the stator core 100, with the arc surface and the plane connected. This configuration helps to optimize the air gap magnetic flux density waveform, reduce harmonics, and suppress cogging torque.

[0081] In some embodiments, the rotor core 21 and the stator core 100 are spaced apart to form a physical air gap, and the minimum value of the physical air gap is δmin, 0.3mm≤δmin≤0.5mm.

[0082] For a permanent magnet synchronous motor, the rotor core 21 is the magnetic field source of the permanent magnet 23. When the size of the permanent magnet 23 is determined, the generated magnetomotive force is constant. When the sizes of both the stator core 100 and the rotor core 21 are determined, the voltage drop of the stator core 100 and the rotor core 21 is also determined. Since the permeability of the stator core 100 and the rotor core 21 is greater than that of air, the physical air gap between the stator core 100 and the rotor core 21 directly determines the permeability of the entire magnetic circuit. The electromagnetic density B = F / (Rs + Rr + Rδ), where Rδ is the air gap reluctance. Rδ is much larger than the reluctance Rs of the stator core 100 and the reluctance Rr of the rotor core 21. The torque generated by the motor is T∝Br×Bt, where Br and Bt are the radial and tangential components of the electromagnetic density B. As the physical air gap gradually decreases, the motor torque gradually increases. Due to the rotor slot 212 design, the physical air gap is non-uniform, resulting in harmonic components in the torque. The harmonic content increases as the physical air gap decreases. A decrease in the motor's fundamental torque leads to a decrease in torque density and an increase in motor cost. According to electromagnetic theory calculations, when the minimum physical air gap is greater than 0.5mm, the torque density decreases significantly, increasing motor cost. When the minimum physical air gap is less than 0.3mm, the harmonic content in the torque is too high, resulting in significant motor noise. Therefore, a value of 0.3mm ≤ δmin ≤ 0.5mm is required to ensure relatively low torque pulsation at the 6th harmonic frequency, which not only reduces motor noise but also lowers motor cost.

[0083] The device using the motor provided in the embodiments of the present invention can reduce operating noise and improve user experience by employing the aforementioned motor.

[0084] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0085] The specific embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An electric motor, characterized in that, include: The stator core (100) includes a plurality of stator lamination groups (1) stacked sequentially along the axial direction of the stator core (100). Each stator lamination group (1) includes a plurality of stator lamination units (11) arranged sequentially along the circumferential direction of the stator core (100). Each stator lamination unit (11) includes a plurality of stator laminations stacked sequentially along the axial direction of the stator core (100). The projections of all the stator laminations in the same stator lamination unit (11) in a plane perpendicular to the axial direction of the stator core (100) coincide. The stator laminations include stator yokes (111) connected sequentially from the outside to the inside. The stator lamination comprises a stator tooth section (112) and a stator crown section (113). The stator tooth section (112) has tooth edge surfaces (1121) that are distributed opposite to each other along the circumferential direction. The stator crown section (113) has two shoulder edge surfaces (1131) that are distributed along the circumferential direction and intersect the two tooth edge surfaces (1121) one by one. The included angle between the shoulder edge surface (1131) and the tooth edge surface (1121) located on the same side of the stator lamination is the shoulder angle. The shoulder angles of two adjacent stator lamination groups (1) along the axial direction of the stator core (100) are different. A rotor core (21) is rotatably disposed within the stator core (100) about its own axis. The rotor core (21) includes a plurality of rotor lamination groups (211) stacked sequentially along its own axial direction. Each rotor lamination group (211) includes a plurality of rotor lamination units (2111) arranged sequentially along the circumferential direction. Each rotor lamination unit (2111) includes a plurality of rotor laminations stacked sequentially along the axial direction of the rotor core (21). The projection weight of all the rotor laminations in the same rotor lamination unit (2111) in a plane perpendicular to the axial direction of the rotor core (21) is... Between two adjacent rotor lamination units (2111) of the same rotor lamination group (211), there is a gap along the circumferential direction between the ends of the two units (2111) away from the axis of the rotor core (21) to form a rotor slot (212); along the axial direction of the rotor core (21), two adjacent rotor lamination groups (211) satisfy the following: the projection of the rotor slot (212) on one of the rotor lamination groups (211) in a plane perpendicular to the axial direction of the rotor core (21) is located inside the projection of the rotor slot (212) on the other rotor lamination group (211); The number of stator lamination groups (1) and rotor lamination groups (211) are the same and correspond one-to-one. The dividing plane (1000) between two adjacent stator lamination groups (1) is coplanar with the dividing plane (1000) between two adjacent rotor lamination groups (211).

2. The motor according to claim 1, characterized in that, One of the two adjacent stator lamination groups (1) is the first stator lamination group (1a), and the other is the second stator lamination group (1b); the shoulder angle of the first stator lamination group (1a) is α1, and the shoulder angle of the second stator lamination group (1b) is α2, where α1 > α2; One of the two adjacent rotor lamination groups (211) is the first rotor lamination group (211a), and the other is the second rotor lamination group (211b); the width of the rotor slot (212) of the first rotor lamination group (211a) along the circumferential direction is br1, and the width of the rotor slot (212) of the second rotor lamination group (211b) along the circumferential direction is br2, where br1 > br2; Two adjacent stator lamination groups (1) and two corresponding adjacent rotor lamination groups (211) satisfy the following: the first stator lamination group (1a) and the first rotor lamination group (211a) are located on one side of the dividing plane (1000), and the second stator lamination group (1b) and the second rotor lamination group (211b) are located on the other side of the dividing plane (1000).

3. The motor according to claim 2, characterized in that, A portion of the plurality of stator lamination groups (1) is the first stator lamination group (1a), and the other portion is the second stator lamination group (1b). The first stator lamination group (1a) and the second stator lamination group (1b) are alternately distributed along the axial direction of the stator core (100). The shoulder angles of all the first stator lamination groups (1a) are equal, and the shoulder angles of all the second stator lamination groups (1b) are equal. And / or, a portion of the plurality of rotor lamination groups (211) is the first rotor lamination group (211a) and the other portion is the second rotor lamination group (211b), the first rotor lamination group (211a) and the second rotor lamination group (211b) are alternately distributed along the axial direction of the rotor core (21); the rotor slots (212) of all the first rotor lamination groups (211a) have equal widths along the circumference of the rotor core (21), and the rotor slots (212) of all the second rotor lamination groups (211b) have equal widths along the circumference of the rotor core (21).

4. The motor according to claim 2, characterized in that, The number of stator lamination groups (1) is odd. The stator lamination groups (1) on both sides of the middle stator lamination group (1) are symmetrically distributed about the middle stator lamination group (1). The rotor lamination groups (211) on both sides of the middle rotor lamination group (211) are symmetrically distributed about the middle rotor lamination group (211).

5. The motor according to claim 4, characterized in that, There is one first stator lamination group (1a) and two second stator lamination groups (1b). The first stator lamination group (1a) is located between the two second stator lamination groups (1b) along the axial direction of the stator core (100). Alternatively, there may be two first stator lamination groups (1a) and one second stator lamination group (1b), with the second stator lamination group (1b) located between the two first stator lamination groups (1a) along the axial direction of the stator core (100).

6. The motor according to any one of claims 2 to 5, characterized in that, 105°≤α2≤109°。 7. The motor according to claim 6, characterized in that, 111°≤α1≤125° and α1-α2>8°.

8. The motor according to any one of claims 2 to 5, characterized in that, 175×π×D i1AV / (360kP)≤br1-br2≤185×π×D i1AV / (360kP), where D i1AV The value represents the average of the minimum inner diameter of the stator core (100) and the maximum outer diameter of the rotor core (21), where k represents the harmonic order and P represents the number of pole pairs of the motor.

9. The motor according to claim 8, characterized in that, P=5, Z=12, 45.9mm≤D i1AV ≤58mm; 1.82≤∣(br1-br2) / (tan(α1+α2-180°))∣≤3.01, Z represents the number of stator lamination units (11) in a stator lamination group (1).

10. A device that uses an electric motor, characterized in that, Including the motor as described in any one of claims 1 to 9.

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