Rotor and motor

Abstract

This invention provides a rotor and a motor. The rotor (10) has multiple permanent magnet slots (11). Any two adjacent permanent magnet slots (11) are symmetrical about a second center line (2). The outer contour of the rotor (10) between any two adjacent second center lines (2) is symmetrical about a first center line (1), and includes: a first arc segment (101) located in the middle, two second arc segments (102) extending outward from both ends of the first arc segment (101), two transition segments (103) extending outward from the two second arc segments (102), and two third arc segments (104) extending outward from the two transition segments (103); the center and radius of the second arc segments (102) are different from those of the first arc segment (101). The rotor of this invention reduces torque pulsation and improves motor efficiency without increasing manufacturing difficulty and cost.

Description

Technical Field

[0001] This invention relates to the field of electric motor technology, and more particularly to a rotor and an electric motor. Background Technology

[0002] In recent years, permanent magnet synchronous motors (PMSMs) have been widely used in household appliances, electric vehicles, and other fields due to their excellent performance, including high power density, high efficiency, light weight, small size, and simple structure, gradually becoming one of the mainstream drive motors. PMSMs are available in two topologies: built-in and surface-mounted. The built-in rotor structure can fully utilize the reluctance torque generated by rotor magnetic circuit asymmetry, improving the motor's power density, and its manufacturing process is also simpler.

[0003] In related technologies, the built-in permanent magnet rotor structure typically uses ferrite with low magnetic properties as the magnetic material. Therefore, the fundamental amplitude of the air gap magnetic flux density in the motor is low. To meet performance requirements, the amount of permanent magnets used and the motor size need to be increased, thus increasing the motor cost. Furthermore, the presence of slots in the permanent magnet synchronous motor structure and harmonic distortion in the armature reaction of the windings cause torque pulsation during operation, resulting in vibration and noise. Summary of the Invention

[0004] To address the aforementioned problems with motors, a new, simple, and effective motor structure can be developed to simultaneously reduce torque ripple and improve motor efficiency without increasing manufacturing difficulty, product cost, or size.

[0005] The present invention aims to at least partially solve one of the technical problems in the related art. To this end, embodiments of the present invention provide a rotor having multiple permanent magnet slots formed thereon;

[0006] The permanent magnet slot has a symmetrical structure, and the first center line of the permanent magnet slot is arranged along the radial direction of the rotor;

[0007] Any two adjacent permanent magnet slots are symmetrical about the second center line, which is arranged radially along the rotor;

[0008] The outer contour of the rotor between any two adjacent second center lines is symmetrical about the first center line and includes: a first arc segment located in the middle, two second arc segments extending outward from both ends of the first arc segment, two transition segments extending outward from the two second arc segments, and two third arc segments extending outward from the two transition segments.

[0009] The centers of the first and third arc segments coincide;

[0010] The center and radius of the second arc segment are different from those of the first arc segment.

[0011] The technical solution of this invention increases the fundamental amplitude of the air gap magnetic flux density by segmenting the rotor's outer circular profile, thereby improving motor efficiency. It also improves the sinusoidal nature of the air gap magnetic flux density waveform, reduces harmonic content, and lowers torque ripple, thus achieving smooth and efficient motor operation. Therefore, this embodiment reduces torque ripple and improves motor efficiency without increasing manufacturing difficulty or cost.

[0012] In some embodiments, both the second arc segment and the transition segment are located inside the circle containing the first arc segment.

[0013] In some embodiments, the radius of the first arc segment and the radius of the circumcircle of the rotor are both R, and the center of the first arc segment coincides with the center line of the rotor's shaft.

[0014] The central angle of the first arc segment is θ1, and it satisfies 5°≤θ1≤0.4×360° / 2P, where P represents the number of pole pairs of the motor.

[0015] In some embodiments, the distance between the center of the second arc segment and the center of the first arc segment is R1, and satisfies 0.1R≤R1≤0.4R.

[0016] In some embodiments, the radius of the second arc segment is R2, and satisfies 0.6R≤R2≤0.9R.

[0017] In some embodiments, the central angle of the second arc segment is θ2, 0°≤θ2≤0.5×360° / 2P, where P represents the number of pole pairs of the motor.

[0018] In some embodiments, the transition segment is a straight line, and the angle between the transition segment and the corresponding first center line is θ3, satisfying 85°≤θ3≤120°.

[0019] In some embodiments, the minimum distance between the second arc segment and the permanent magnet slot is b, and satisfies 0.6d≤b≤1.2d, where d represents the thickness of a single silicon steel plate of the rotor.

[0020] In some embodiments, the minimum spacing between adjacent permanent magnet slots is a, which satisfies 0.4mm≤a≤1mm.

[0021] In some embodiments, the rotor is provided with a plurality of first process holes and a plurality of second process holes;

[0022] The centers of the plurality of first process holes are located on the same circle and are evenly distributed around the center line of the rotor shaft. The first process holes are located between the permanent magnet slot and the outer circle of the rotor.

[0023] The centers of the multiple second process holes are located on the same circle and are evenly distributed around the center line of the rotor shaft. The second process holes are located between the permanent magnet slot and the rotor shaft.

[0024] This invention also provides an electric motor, including a rotor according to any embodiment of the invention. This motor has the advantage of high efficiency.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0027] Figure 1 This is a schematic diagram of the rotor structure in one embodiment of the present invention, wherein a permanent magnet is hidden in a permanent magnet slot;

[0028] Figure 2 This is a partial structural schematic diagram of the rotor in one embodiment of the present invention, wherein the permanent magnet is not shown;

[0029] Figure 3 yes Figure 2 A magnified view of a portion of position A in the middle;

[0030] Figure 4 This is a schematic diagram of the rotor structure in one embodiment of the present invention, wherein a permanent magnet is hidden in a permanent magnet slot;

[0031] Figure 5 This is a simulation result of torque pulsation before and after rotor optimization in one embodiment of the present invention.

[0032] Figure label:

[0033] 1-First centerline; 2-Second centerline; 3-Permanent magnet;

[0034] 10-Rotor; 11-Permanent magnet slot; 12-First process hole; 13-Second process hole;

[0035] 101 - First arc segment; 102 - Second arc segment; 103 - Transition segment; 104 - Third arc segment. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] This embodiment provides a rotor 10 for an electric motor. In one embodiment, see [reference needed]. Figures 1-3 The rotor 10 has multiple permanent magnet slots 11; permanent magnets 3 are placed in the permanent magnet slots 11.

[0038] The permanent magnet slot 11 has a symmetrical structure, and the first center line 1 of the permanent magnet slot 11 is arranged radially along the rotor 10; each permanent magnet slot 11 has its own first center line 1, which is arranged radially along the rotor 10. The shape of the permanent magnet slot 11 can be an arc shape as shown in the figure.

[0039] Any two adjacent permanent magnet slots 11 are symmetrical about the second center line 2, which is arranged radially along the rotor 10; that is, multiple permanent magnet slots 11 are arranged in a circular array around the center line of the rotor 10's axis of rotation, which is the rotor 10's axis of rotation. Figure 1 The center position of the circle.

[0040] See Figure 2 The outer contour of the rotor 10 between any two adjacent second center lines 2 is symmetrical about the first center line 1, and includes: a first arc segment 101 located in the middle, two second arc segments 102 extending outward from both ends of the first arc segment 101, two transition segments 103 extending outward from the two second arc segments 102, and two third arc segments 104 extending outward from the two transition segments 103.

[0041] The centers of the first arc segment 101 and the third arc segment 104 coincide and have the same radius. In other words, the first arc segment 101 and the third arc segment 104 are different positions of the same circle. Furthermore, in this embodiment, the circle in which the first arc segment 101 and the third arc segment 104 are located is the circumcircle 100 of the rotor 10.

[0042] The center and radius of the second arc segment 102 are different from those of the first arc segment 101. As a result, the gap between the outer contour of the rotor 10 and the adapted stator is uneven. Through experiments and software testing, this rotor structure can increase the amplitude of the air gap magnetic flux density fundamental wave and improve motor efficiency.

[0043] Since the modification cost of the outer contour of the rotor 10 is low and the improvement difficulty is small, it will not increase the cost compared with the original technology. Therefore, this embodiment reduces torque pulsation and improves motor efficiency without increasing manufacturing difficulty and cost.

[0044] The technical solution of the above embodiment, through a segmented design of the rotor's outer circular contour, increases the fundamental amplitude of the air gap magnetic flux density compared to existing built-in permanent magnet synchronous motors, thereby improving motor efficiency. It also improves the sinusoidal nature of the air gap magnetic flux density waveform, reduces the harmonic content of the air gap magnetic flux density, and lowers torque ripple, thus achieving smooth and efficient motor operation. Therefore, this embodiment reduces torque ripple and improves motor efficiency without increasing manufacturing difficulty or cost.

[0045] In some embodiments, the second arc segment 102 and the transition segment 103 are both located inside the circle containing the first arc segment 101. In this embodiment, the circle containing the first arc segment 101, the circle containing the third arc segment 104, and the circumcircle 100 of the rotor 10 coincide; therefore, it can also be said that the second arc segment 102 and the transition segment 103 are both located inside the circumcircle 100 of the rotor 10. For example, the radius of the second arc segment 102 can be smaller than the radius of the first arc segment 101.

[0046] This improves the sinusoidality of the air gap magnetic flux density waveform, reduces the harmonic content of the air gap magnetic flux density, and helps to reduce torque pulsation, thereby achieving smooth and efficient operation of the motor.

[0047] In some embodiments, see Figure 2 The radius of the first arc segment 101 and the radius of the circumcircle 100 of the rotor 10 are both R. In this embodiment, R = 55mm-62mm. The center of the first arc segment 101 coincides with the center line of the rotor shaft of the rotor 10. The central angle of the first arc segment 101 is θ1, and it satisfies 5°≤θ1≤0.4×360° / 2P, where P represents the number of pole pairs of the motor. For example, the value of θ1 can be 10°, 11°, 12°, 13°, 14°, 15°, etc. In this example, θ1 = 11°~14°.

[0048] In some embodiments, the distance between the center of the second arc segment 102 and the center of the first arc segment 101 is R1, and satisfies 0.1R ≤ R1 ≤ 0.4R. The positions of the centers of different second arc segments 102 are all different. Figure 1 In the diagram, O is the center of the first arc segment 101, and O1 is the center of the second arc segment 102. In this example, R1 = 6mm to 7mm.

[0049] In some embodiments, the radius of the second arc segment 102 is R2, and satisfies 0.6R≤R2≤0.9R. In this example, R2=23~24mm.

[0050] In some embodiments, the central angle of the second arc segment 102 is θ2, 0°≤θ2≤0.5×360° / 2P, where P represents the number of pole pairs of the motor. In this example, θ2=19°~21°.

[0051] In some embodiments, the transition segment 103 is a straight line, and the angle between the transition segment 103 and the corresponding first center line 1 is θ3, satisfying 85°≤θ3≤120°. In this example, θ3=89°~91°.

[0052] In some embodiments, see Figure 3 The minimum distance between the second arc segment 102 and the permanent magnet slot 11 is b, and satisfies 0.6d≤b≤1.2d, where d represents the thickness of a single silicon steel plate of the rotor 10. In this example, d=0.35mm, b=0.21mm~0.22mm.

[0053] In some embodiments, the minimum spacing between adjacent permanent magnet slots 11 is 'a', satisfying 0.4mm ≤ a ≤ 1mm. In this example, a = 0.65mm to 0.75mm.

[0054] In some embodiments, see Figure 4 The rotor 10 has multiple first process holes 12 and multiple second process holes 13. The centers of the multiple first process holes 12 are located on the same circle and are evenly distributed around the center line of the rotor shaft of the rotor 10. The first process holes 12 are located between the permanent magnet slot 11 and the outer circle 100 of the rotor 10. The centers of the multiple second process holes 13 are located on the same circle and are evenly distributed around the center line of the rotor shaft of the rotor 10. The second process holes 13 are located between the permanent magnet slot 11 and the rotor shaft of the rotor 10.

[0055] The first process hole 12 and the second process hole 13 can be used to set rivets to connect multiple monolithic silicon steel plates into one piece. The setting of the first process hole 12 and the second process hole 13 helps to improve the q-axis magnetic circuit and air gap magnetic flux density waveform, and reduces cogging torque and torque pulsation while increasing the saliency ratio.

[0056] This embodiment also provides an electric motor, including the rotor of any of the above embodiments.

[0057] To verify the actual effectiveness of the technical solution in this embodiment, simulation calculations were used to compare and analyze the changing trends of motor performance and torque ripple before and after optimization. Figure 5 It can be seen that the torque fluctuation of the motor decreased from 32.99% (81.5457 (peak) / 247.1711 (average) before optimization) to 21.029% (51.9308 (peak) / 246.9463 (average) after optimization), and the motor efficiency (0.247 N·m, 27 Hz rated operating condition) increased from 92.99% before optimization to 93.09% after optimization. It is evident that through rotor structure optimization in this method, the motor torque fluctuation is significantly reduced, and the motor efficiency is also improved to a certain extent.

[0058] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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.

[0059] Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0060] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0062] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0063] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A rotor (10), characterized in that, The rotor (10) has multiple permanent magnet slots (11); The permanent magnet slot (11) has a symmetrical structure, and the first center line (1) of the permanent magnet slot (11) is arranged radially along the rotor (10); Any two adjacent permanent magnet slots (11) are symmetrical about the second center line (2), the second center line (2) is arranged along the radial direction of the rotor (10), and the rotor (10) is provided with a plurality of first process holes (12) and a plurality of second process holes (13). The centers of the multiple first process holes (12) are located on the same circle and are evenly distributed around the rotation axis center line of the rotor (10). The first process holes (12) are located between the permanent magnet groove (11) and the outer circle (100) of the rotor (10). The centers of the multiple second process holes (13) are located on the same circle and are evenly distributed around the center line of the rotor (10) shaft. The second process holes (13) are located between the permanent magnet slot (11) and the rotor (10) shaft. The outer contour of the rotor (10) between any two adjacent second center lines (2) is symmetrical about the first center line (1) and includes: a first arc segment (101) located in the middle, two second arc segments (102) extending outward from both ends of the first arc segment (101), two transition segments (103) extending outward from the two second arc segments (102), the second arc segments (102) and the transition segments (103) are both located inside the circle where the first arc segment (101) is located, and two third arc segments (104) extending outward from the two transition segments (103), the transition segments (103) being straight lines; The centers of the first arc segment (101) and the third arc segment (104) coincide; The center and radius of the second arc segment (102) are different from those of the first arc segment (101). The radius of the first arc segment (101) and the radius of the circumcircle (100) of the rotor (10) are both R. The center of the first arc segment (101) coincides with the center line of the rotor shaft of the rotor (10). The distance between the center of the second arc segment (102) and the center of the first arc segment (101) is R1, and satisfies 0.1R≤R1≤0.4R. The minimum distance between the second arc segment (102) and the permanent magnet slot (11) is b, and satisfies 0.6d≤b≤1.2d, where d represents the thickness of a single silicon steel plate of the rotor (10).

2. The rotor (10) according to claim 1, characterized in that, The central angle of the first arc segment (101) is θ1, and satisfies 5°≤θ1≤0.4×360° / 2P, where P represents the number of pole pairs of the motor.

3. The rotor (10) according to claim 1, characterized in that, The radius of the second arc segment (102) is R2, and satisfies 0.6R≤R2≤0.9R.

4. The rotor (10) according to claim 1, characterized in that, The central angle of the second arc segment (102) is θ2, 0°≤θ2≤0.5×360° / 2P, where P represents the number of pole pairs of the motor.

5. The rotor (10) according to claim 1, characterized in that, The angle between the transition segment (103) and the corresponding first center line (1) is θ3, and satisfies 85°≤θ3≤120°.

6. The rotor (10) according to claim 1, characterized in that, The minimum spacing between adjacent permanent magnet slots (11) is a, which satisfies 0.4mm≤a≤1mm.

7. An electric motor, characterized in that, Includes the rotor as described in any one of claims 1-6.

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