Rotor, stator, motor and household appliance

Abstract

The present application provides a rotor, a stator, a motor and a household appliance. A rotor (100) is used for a motor. The motor comprises a stator (200). The stator (200) has an inner peripheral wall (210) arranged around the rotor (100). The rotor (100) is disposed in the stator (200), and the rotor (100) can rotate around a rotation axis. The rotor (100) comprises first iron core units (110) and second iron core units (120). Each first iron core unit (110) can define a first air gap (130) together with the inner peripheral wall (210), and the first air gap (130) has a first magnetic flux density curve; and each second iron core unit (120) can define a second air gap (140) together with the inner peripheral wall (210), and the second air gap (140) has a second magnetic flux density curve, wherein the first magnetic flux density curve does not coincide with the second magnetic flux density curve.

Description

Rotors, stators, motors and household appliances

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202310977966.X, filed on August 3, 2023, entitled “Rotor, Stator, Motor and Household Appliances,” the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of motor technology, and in particular to a rotor, a stator, a motor and a household appliance. Background Art

[0004] Permanent magnet synchronous motors (PMSMs) offer high power and torque densities and are widely used in household appliances. To meet current demands for high power density and low noise, these motors are required to meet these requirements. One factor that can affect motor performance is the harmonics generated during operation. The primary source of harmonics is the cogging torque caused by the slotted structure between the rotor and stator. This cogging torque causes torque ripple in the PMSM, leading to speed fluctuations and reduced motor efficiency. Torque ripple also generates additional vibration and noise.

[0005] At present, one method to reduce the torque pulsation of the motor is to design the outer contour of the rotor or the inner contour of the stator into an irregular outer contour wall surface to form an uneven air gap between the stator and the rotor of the motor. The uneven air gap can make the air gap magnetic flux density distribution waveform under the magnet correspond to the harmonic waveform of the torque pulsation, which is beneficial to reducing the cogging torque. However, the stator / rotor of the related art often only adopts one irregular outer contour structure in each core unit. With the diversification of the stator / rotor structure design, the single type of stator / rotor uneven surface structure cannot effectively suppress specific harmonic waveforms. For example, the stator / rotor has a variety of slot structures, so that a variety of harmonic waveforms will be generated during the operation of the motor; or the torque pulsation has a more complex harmonic waveform, and the irregular wall surface of the stator / rotor unit of a single form cannot adapt to the changing period of the harmonic waveform. Therefore, there is a need to seek a diversified stator / rotor unit contour structure to effectively suppress the complex harmonic waveform of the motor. Summary of the Invention

[0006] The main purpose of this application is to propose a rotor, a stator, a motor and a household appliance that can at least partially solve one of the above technical problems.

[0007] To achieve the above objectives, the embodiments of the first aspect of the present application adopt the following technical solutions:

[0008] A rotor for a motor, the motor comprising a stator, the stator having an inner circumferential wall disposed around the rotor, the rotor being disposed within the stator and capable of rotating about a rotation axis, the rotor comprising a first iron core unit and a second iron core unit;

[0009] The first core unit and the inner peripheral wall can define a first air gap together, and the first air gap has a first magnetic flux density curve; and

[0010] The second core unit and the inner peripheral wall can define a second air gap together, and the second air gap has a second magnetic flux density curve;

[0011] The first magnetic flux density curve does not overlap with the second magnetic flux density curve.

[0012] In some embodiments, the first core unit has a first wall surface facing the inner circumferential wall, and the orthographic projection of the first wall surface on a plane perpendicular to the rotation axis is a first projection; the second core unit has a second wall surface facing the inner circumferential wall, and the orthographic projection of the second wall surface on a plane perpendicular to the rotation axis is a second projection; the shape of the first projection is different from the shape of the second projection, and / or the size of the first projection is different from the size of the second projection.

[0013] In some embodiments, the first core unit has a first wall surface facing the inner circumferential wall, the orthographic projection of the first wall surface on a plane perpendicular to the rotation axis is a first projection, and the first projection is curved; and / or, the second core unit has a second wall surface facing the inner circumferential wall, the orthographic projection of the second wall surface on a plane perpendicular to the rotation axis is a second projection, and the second projection is curved.

[0014] In some embodiments, the first core unit has a first wall surface facing the inner circumferential wall, an orthographic projection of the first wall surface on a plane perpendicular to the rotation axis is a first projection, the first projection includes a first arc and a second arc, the first arc corresponds to a first center, the second arc corresponds to a second center, and the first center and the second center do not coincide with each other;

[0015] and / or,

[0016] The second core unit has a second wall surface facing the inner circumferential wall, and the orthographic projection of the second wall surface on a plane perpendicular to the rotation axis is a second projection. The second projection includes a third arc and a fourth arc. The third arc corresponds to a third center, and the fourth arc corresponds to a fourth center. The third center and the fourth center do not coincide with each other.

[0017] In some embodiments, along the radial direction of the rotor, a minimum dimension L1 between the rotor and the inner circumferential wall satisfies the following: 0.2 mm ≤ L1 ≤ 0.5 mm.

[0018] In some embodiments, along the radial direction of the rotor, a minimum dimension L1 between the rotor and the inner circumferential wall and a maximum dimension L2 between the rotor and the inner circumferential wall satisfy the following: 0.15≤L1 / L2≤0.75.

[0019] In some embodiments, the first core unit and the second core unit are spaced apart from each other, and the rotor further includes a cladding layer, which fills a gap between the first core unit and the second core unit.

[0020] In some embodiments, the rotor further includes a permanent magnet, a receiving space is defined between the first core unit and the second core unit, the permanent magnet is disposed in the receiving space, and the covering layer covers one end of the permanent magnet radially away from the rotation axis along the rotor.

[0021] In some embodiments, the rotor includes a plurality of core units arranged circumferentially adjacent to each other around the rotation axis, the shape and structure of each core unit are the same as the first core unit or the second core unit, and each core unit is arranged in a ring array with the rotation axis as the central axis.

[0022] In some embodiments, the rotor includes a plurality of circumferentially adjacently arranged core units around the axis of rotation; the core units are disconnected from each other, or the rotor further includes a first magnetic bridge, the first magnetic bridge is located on the side of each core unit close to the axis of rotation, and the first magnetic bridge is used to connect at least two core units, or the rotor further includes a second magnetic bridge, the second magnetic bridge is located on the side of each core unit away from the axis of rotation, and the second magnetic bridge is used to connect at least two core units.

[0023] The embodiment of the second aspect of the present application further provides a stator for a motor, the motor including a rotor having an outer peripheral wall arranged around the stator, the rotor being arranged in the stator, and the stator including a third core unit and a fourth core unit;

[0024] The third core unit can define a third air gap together with the outer peripheral wall, and the third air gap has a third magnetic flux density curve; and

[0025] The fourth core unit and the outer peripheral wall can define a fourth air gap together, and the fourth air gap has a fourth magnetic flux density curve;

[0026] The third magnetic flux density curve does not overlap with the fourth magnetic flux density curve.

[0027] An embodiment of the third aspect of the present application further provides a motor, comprising the stator of any one of the embodiments of the second aspect above, and a rotor.

[0028] An embodiment of the fourth aspect of the present application further provides a motor, comprising the rotor of any one of the embodiments of the first aspect above, and a stator.

[0029] The embodiment of the fifth aspect of the present application further provides a household appliance, comprising the motor of the embodiment of the fourth aspect mentioned above. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0031] FIG1 is a schematic side view of a rotor and a stator combined in one embodiment of the present application;

[0032] FIG2 is a partial enlarged schematic diagram of point A in FIG1 ;

[0033] FIG3 is a schematic diagram of a first magnetic flux density curve in a first rectangular coordinate system in the embodiment shown in FIG1 of the present application;

[0034] FIG4 is a schematic diagram of a second magnetic flux density curve in a second rectangular coordinate system in the embodiment shown in FIG1 of the present application;

[0035] FIG5 is a side view schematic diagram of the combination of the first core unit and the second core unit provided in the embodiment shown in FIG1 of the present application;

[0036] FIG6 is a side view schematic diagram of a first core unit and a second core unit combined in another embodiment of the present application;

[0037] FIG7 is a side view schematic diagram of a first core unit and a second core unit combined in yet another embodiment of the present application;

[0038] FIG8 is a side schematic diagram of the first core unit provided in the embodiment shown in FIG1 of the present application;

[0039] FIG9 is a side view schematic diagram of the first core unit provided in the embodiment shown in FIG6 of the present application;

[0040] FIG10 is a side view schematic diagram of the combination of the first core unit and the second core unit provided in the embodiment shown in FIG7 of the present application;

[0041] FIG11 is a schematic side view of a rotor provided in another embodiment of the present application;

[0042] FIG12 is a schematic side view of a rotor provided in another embodiment of the present application;

[0043] FIG13 is a side view schematic diagram of a rotor provided in another embodiment of the present application;

[0044] FIG14 is a side view schematic diagram of a stator and a rotor combined in an embodiment of the second aspect of the present application; and

[0045] FIG15 is a partial enlarged view of point B in FIG14 .

[0046] Description of Figure Numbers:

[0047] 100-rotor;

[0048] 110 - first core unit; 111 - first wall; 112 - first projection; 1121 - first arc; 1122 - second arc;

[0049] 120 - second core unit; 121 - second wall surface; 122 - second projection;

[0050] 130-first air gap;

[0051] 140- second air gap;

[0052] 150-cladding layer;

[0053] 160-Permanent magnet;

[0054] 170-first magnetic bridge;

[0055] 180-second magnetic bridge;

[0056] 200 (300) - stator;

[0057] 210-inner peripheral wall;

[0058] 310-third core unit;

[0059] 320-fourth core unit;

[0060] 330- third air gap;

[0061] 340-fourth air gap;

[0062] 400 - rotor; 410 - outer peripheral wall.

[0063] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. Modes for Carrying Out the Invention

[0064] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0065] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0066] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or", "and / or" or "and / or" appear in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0067] Permanent magnet synchronous motors are prone to torque pulsation during operation, which reduces motor efficiency and generates additional vibration and noise. One current method for reducing motor torque pulsation is to design the rotor outer profile or stator inner profile into an irregular outer profile wall surface to form an uneven air gap between the motor's stator and rotor. This uneven air gap can make the air gap magnetic flux density distribution waveform under the magnet correspond to the harmonic waveform of the torque pulsation, which is beneficial for reducing cogging torque. However, the stators and rotors of related technologies often only use one irregular outer profile structure in each core unit. With the diversification of stator and rotor structure designs, a single type of stator and rotor uneven surface structure cannot effectively suppress specific harmonic waveforms. For example, the stator and rotor have multiple types of slot structures, which will generate multiple harmonic waveforms during motor operation; or the torque pulsation has a more complex harmonic waveform, and a single type of stator and rotor unit irregular wall surface cannot adapt to the changing period of the harmonic waveform. Therefore, there is a need to seek a diversified stator and rotor unit contour structure to effectively suppress the complex harmonic waveforms of the motor.

[0068] In view of this, referring to Figures 1-13, an embodiment of the first aspect of the present application provides a rotor 100 for use in an electric motor. The electric motor includes a stator 200. The stator 200 has an inner circumferential wall 210 disposed around the rotor 100. The rotor 100 is disposed within the stator 200 and is capable of rotating about a rotation axis. In different embodiments of the above-mentioned rotor 100, the rotor 100 may be a rotor core composed of multiple core units, or a rotor assembly composed of a rotor core and other components such as a rotating shaft; the same applies to the stator 200. It is understood that the rotor 100 can be disposed relative to the stator 200. The stator 200 can have an inner circumferential wall 210, and the inner circumferential wall 210 can define a cavity for receiving the rotor. The rotor 100 can be located inside the stator 200 (placed within the cavity) and rotate relative to the stator 200 about the rotation axis. It should be noted that, in some embodiments, the inner circumferential wall 210 of the stator 200 may be a continuously extended wall defining an annular cavity; see FIG1 . In other embodiments, the inner circumferential wall 210 may be defined by a plurality of spaced inner wall sections, that is, the inner circumferential wall 210 may be disconnected between the core units of the stator 200 .

[0069] 1-2 , rotor 100 includes a first core unit 110 and a second core unit 120 . In some embodiments, the rotor core may include multiple core units arranged around the rotor core's rotational axis, each of which may include the aforementioned first core unit 110 and second core unit 120 . The first core unit 110 and the second core unit 120 may be adjacently arranged along the circumferential direction of the rotational axis. The "circumferential direction of the rotational axis" is defined as follows: When viewed along a direction parallel to the rotational axis, the circumferential direction of the rotational axis is the clockwise direction.

[0070] Referring to FIG. 2 , the first core unit 110 and the inner circumferential wall 210 can collectively define a first air gap 130 . Accordingly, the second core unit 120 and the inner circumferential wall 210 can collectively define a second air gap 140 . It is understood that the first air gap 130 can be represented by the gap between the wall surface of the first core unit 110 facing the inner circumferential wall 210 and the inner circumferential wall 210 , and the second air gap 140 can be represented by the gap between the wall surface of the second core unit 120 facing the inner circumferential wall 210 and the inner circumferential wall 210 . In some embodiments, when the permanent magnet motor is operating, permanent magnets 160 are disposed within the rotor 100 . The permanent magnets 160 can create a certain magnetic field within the first air gap 130 and the second air gap 140 , as well as a corresponding air gap magnetic flux density. The spatial arrangement and size of the air gaps affect the magnetic flux density. Therefore, the magnetic flux density of the air gap is related to the structure of the air gap, and the magnetic flux density at each location will vary depending on the air gap structure at that location. Based on this, the first air gap 130 has a first magnetic flux density curve, and the second air gap 140 has a second magnetic flux density curve.

[0071] Referring to FIG. 3 , the following definition of "first air gap 130 having a first magnetic flux density curve" is provided: the first magnetic flux density curve can be represented in a first rectangular coordinate system, where the horizontal axis of the rectangular coordinate system represents various locations of the first air gap 130 circumferentially along the rotation axis, and the vertical axis represents the first magnetic flux density. A value of 0 on the horizontal axis can represent an end position of the first air gap 130 circumferentially along the rotation axis. The first magnetic flux density of the first air gap 130 at various locations circumferentially along the rotation axis exhibits a certain variation trend, and this variation trend is reflected as a first magnetic flux density curve in the coordinate system. Therefore, in the first rectangular coordinate system, any point on the first magnetic flux density curve represents the first magnetic flux density of the first air gap 130 corresponding to the coordinate value of the horizontal axis at that point.

[0072] Accordingly, referring to FIG4 , the following definition of "the second air gap 140 having a second magnetic flux density curve" is given: the second magnetic flux density curve can be represented in a second rectangular coordinate system, wherein the horizontal axis of the rectangular coordinate system is used to represent various positions of the second air gap 140 along the circumference of the rotation axis, and the vertical axis is used to represent the second magnetic flux density. The value 0 on the horizontal axis can represent an end position of the second air gap 140 along the circumference of the rotation axis. The second magnetic flux density of the second air gap 140 at various positions along the circumference of the rotation axis has a certain variation trend, and the variation trend as a whole is reflected in the coordinate system as the second magnetic flux density curve. Therefore, in the second rectangular coordinate system, any point on the second magnetic flux density curve is represented by the second magnetic flux density of the second air gap 140 corresponding to the horizontal axis coordinate value of the point.

[0073] It should be noted that the first magnetic flux density curve and the second magnetic flux density curve of the embodiment of the present application only represent the changing trend of the magnetic flux density in the coordinate system. Therefore, the first magnetic flux density curve and the second magnetic flux density curve can be composed of curve segments or straight line segments, or can be composed of straight line segments as a whole.

[0074] The above-mentioned first magnetic flux density curve does not overlap with the second magnetic flux density curve. It should be noted that the above-mentioned non-overlap means incomplete overlap (ignoring the incomplete overlap caused by error factors). And the comparison method for the non-overlap of the magnetic flux density curves is: remove the rectangular coordinate system and only compare the curve graphs of the first magnetic flux density curve and the second magnetic flux density curve. Therefore, the first magnetic flux density curve and the second magnetic flux density curve have different shapes. It can be seen that the first core unit 110 and the second core unit 120 can have different structural designs to form the above-mentioned non-overlapping magnetic flux density curves. Specifically, referring to Figures 1-2, the first core unit 110 and the second core unit 120 can have different outer wall shapes.

[0075] Explanation of different outer wall shapes. For example, in one embodiment, the above-mentioned different outer wall shapes can be outer wall shapes of different compositions, see Figure 5. Specifically, in this embodiment, along the direction parallel to the rotation axis, the outer wall projection of the first core unit 110 can be composed of a first arc segment; the outer wall projection of the second core unit 120 can be composed of: a second arc segment, a third arc segment, and a straight line segment. In this embodiment, the outer wall shapes of the first core unit 110 and the second core unit 120 are different. In another embodiment, the above-mentioned different outer wall shapes can be outer wall shapes of the same structure. Specifically, refer to Figure 6 or Figure 7. In this embodiment, the outer wall projection of the first core unit 110 can be composed of: a first arc segment and a second arc segment that are concentrically arranged, and a third arc segment that is not concentric with the first arc segment and the second arc segment; the outer wall projection of the second core unit 120 can be composed of: the above-mentioned first arc segment and the second arc segment, and a fourth arc segment that is not concentric with the first arc segment and the second arc segment, wherein the third arc segment is not concentric with the fourth arc segment. In this embodiment, the first core unit 110 and the second core unit 120 both have three arc segments, which are still considered to be different outer wall shapes, and have non-overlapping first magnetic flux density curves and second magnetic flux density curves.

[0076] Based on the above embodiments, it can be concluded that in some embodiments, the rotor 100 of the present application includes a first core unit 110 and a second core unit 120, which can respectively define a first air gap 130 and a second air gap 140 together with the inner circumferential wall 210 of the stator 200. The magnetic flux density of the air gap at various locations along the circumference of the rotation axis can exhibit a certain variation trend, which can be represented by a magnetic flux density curve. The two air gaps have different magnetic flux density curves, and the difference in magnetic flux density curves can reflect the different outer wall structures of the first core unit 110 and the second core unit 120. The different magnetic flux density curves (or different air gap structures) between the core units of the rotor 100 can correspond to the harmonics generated at various locations along the circumference of the rotation axis. The different magnetic flux density curves between the units of the rotor 100 can further suppress various harmonic waveforms. Therefore, the rotor 100 of the embodiment of the present application has a variety of core unit air gap structures, which can adapt to different harmonics and effectively suppress multiple harmonics, giving full play to the magnetic permeability modulation effect, thereby helping to improve motor efficiency, reduce tangential electromagnetic force harmonics, and reduce vibration noise.

[0077] In some embodiments, the first core unit 110 may have an irregular outer wall surface, and similarly, the second core unit 120 may also have an irregular outer wall surface, so that this embodiment can suppress harmonics within the circumferential rotation range of a single core unit and reduce the interference of tangential electromagnetic forces.

[0078] It is understood that the first core unit 110 and the second core unit 120 have different outer wall structures to form different air gap structures between the core units. In order to enable the first air gap 130 or the second air gap 140 to have a non-uniform air gap within the first core unit 110 or the second core unit 120, thereby leveraging the harmonic suppression effect of the non-uniform air gap within a single core unit, the composition of the core unit walls can be designed accordingly. Specifically, referring to FIG8 , in some embodiments, the first core unit 110 can have a first wall 111 facing the inner circumferential wall. It is understood that the first wall 111 is the wall of the first core unit 110 facing the inner circumferential wall, and the first wall 111 can jointly define the first air gap 130 with the inner circumferential wall 210. The orthographic projection of the first wall 111 on a plane perpendicular to the rotation axis is the first projection 112. In other words, the first projection 112 can be understood as the projection outline formed by the first wall 111 when viewed in a direction parallel to the rotation axis. Accordingly, in some embodiments, the second core unit 120 may have a second wall surface 121 facing the inner circumferential wall. Accordingly, the second wall surface 121 can be understood as the wall surface of the second core unit 120 facing the inner circumferential wall, and the second wall surface 121 can, together with the inner circumferential wall 210, define a second air gap 140. The orthographic projection of the second wall surface 121 on a plane perpendicular to the rotation axis is a second projection 122. For a description of the second projection 122, see the first projection 112.

[0079] Regarding the specific shapes of the first projection 112 and the second projection 122 described above, in some embodiments, the first projection 112 can be composed of straight line segments, and / or the second projection 122 can be composed of straight line segments. To smooth the magnetic flux density curve, thereby stabilizing the harmonic suppression effect of the uneven air gap and preventing the generation of additional harmonics, as shown in Figures 5-9, in some embodiments, the first projection 112 can be curved, and / or the second projection 122 can be curved. The aforementioned curved shape can be understood as defining the shape of the first projection 112 having at least one curved segment, or the second projection 122 having at least one curved segment. In various embodiments, the first projection 112 can include at least one curved segment and at least one straight line segment, or the first projection 112 can be composed entirely of curved segments. The same applies to the second projection 122. The curved shape of the first projection 112 / the second projection 122 can smooth the corresponding magnetic flux density curve and reduce harmonic fluctuations.

[0080] It should be noted that the specific shapes and variation trends of the first and second projections 112 and 122 described above must correspond to the harmonic variation trends during actual motor operation. Therefore, the specific design of the outer wall surface of the first core unit 110 or the second core unit 120 must refer to the motor selection and test data. For example, the embodiments of this application provide some core unit outer wall structure forms for reference.

[0081] For the above-mentioned first projection 112 and second projection 122, in some embodiments, the different air gap structures between the core units can be specifically reflected as different projection sizes or shapes of the core unit wall surfaces. Therefore, referring to Figures 5-7, in some embodiments, the shape of the first projection can be different from the shape of the second projection, and / or the size of the first projection can be different from the size of the second projection.

[0082] Regarding the outer wall of the core unit. Referring to FIG8 , in some embodiments, the first core unit 110 has a first wall 111 facing the inner circumferential wall. The orthographic projection of the first wall 111 onto a plane perpendicular to the rotation axis is a first projection 112. For details regarding the first wall 111 and the first projection 112, reference can be made to the above-described related descriptions. The first projection 112 may include a first arc 1121 and a second arc 1122. It will be appreciated that the first arc 1121 and the second arc 1122 may correspond to the shapes that constitute the first projection 112. Therefore, in different embodiments, the first projection 112 may consist solely of the first arc 1121 and the second arc 1122, or may also consist of the first arc 1121, the second arc 1122, and other line segments (including straight and curved segments). For example, referring to FIG8 , in some embodiments, the first projection 112 may consist of two first arcs 1121, one on either side, and a second arc 1122 located between the first and second arcs. The first arc 1121 can be arranged concentrically with the third arc. Referring to FIG9 , in other embodiments, the first projection 112 can be composed of the first arc 1121 and the second arc 1122. Regarding the aforementioned arc segment arrangement, the first arc 1121 corresponds to a first center, and the second arc 1122 corresponds to a second center. It will be understood that the first center is the center of the circle used to form the first arc 1121. The first arc 1121 uniquely corresponds to one first center, and the same applies to the second center. In some embodiments, the first projection 112 can also be composed of more arc segments or straight line segments.

[0083] Regarding the setting of the above-mentioned first center of the circle and the second center of the circle. Referring to Figure 8 or Figure 9, in some embodiments, the first center of the circle and the second center of the circle may not coincide with each other. In other words, the position limitation of the above-mentioned first center of the circle and the second center of the circle can be understood as the first center of the circle and the second center of the circle being non-concentrically set. By setting at least two arc segments on the outer wall surface of the core unit, and the two arc segments being non-concentric, the two arc segments on the first projection 112 or the second projection 122 can form different air gap structures with the inner circumferential wall 210, respectively, so that the core unit has an uneven air gap structure. In the process of the rotor 100 rotating relative to the stator 200 and passing through the two arc segments in the circumferential direction, the size of the air gap at various circumferential positions along the axis of rotation can have a certain change trend (for example, the air gap gradually increases or gradually decreases), so that the air gap can more effectively suppress the motor harmonics.

[0084] Accordingly, in some embodiments, the second core unit 120 has a second wall surface 121 facing the inner circumferential wall, and the orthographic projection of the second wall surface 121 on a plane perpendicular to the rotation axis is a second projection 122. The second projection 122 may include a third arc and a fourth arc. The third arc corresponds to a third center, and the fourth arc corresponds to a fourth center. Accordingly, in some embodiments, the third center and the fourth center may not coincide. In addition, the configuration and definition of the second wall surface 121, the second projection 122, the third arc, and the fourth arc can refer to the above-mentioned relevant description of the first wall surface 111 and its arc segment.

[0085] Regarding the trend of wall structure changes of the core unit along the circumferential direction. Taking the first core unit 110 as an example, in some embodiments, in the process of the first air gap 130 moving from one end position to another end position along the circumference of the rotation axis, the first air gap 130 formed at each point on the first wall 111 can gradually become larger, or gradually become smaller, or first increase and then decrease, or first decrease and then increase. It can be understood that the above-mentioned trend of air gap changes can correspond to the actual motor harmonics generated, and can play a role in reducing the harmonic rate of the motor back electromotive force and improving the efficiency of the motor. It should be noted that the size of the air gap at each point at various positions of the rotor 100 along the circumference of the rotation axis can be jointly defined by the core unit wall corresponding to the point and the inner circumferential wall 210.

[0086] Next, the design of the first air gap 130 and the second air gap 140 is further optimized. To reduce the vibration noise of the motor and optimize the magnetic field within the air gap, the air gap reluctance can be made to have a sinusoidal distribution. Since the air gap reluctance is related to the air gap size and the outer wall surface of the rotor 100, the outer contour of the rotor core also needs to be optimized.

[0087] Through experiments and analysis, it was found that when the minimum size of the air gap is within a certain numerical range, it can more accurately ensure that the motor has high efficiency, low harmonic content, and low magnetic field distortion rate. Specifically, referring to Figure 2, in some embodiments, along the radial direction of the rotor 100, the minimum size L1 of the rotor 100 from the inner circumferential wall 210 satisfies: 0.2mm≤L1≤0.5mm. It can be understood that the minimum size of the rotor 100 from the inner circumferential wall 210 is the distance between the rotor 100 and the inner circumferential wall 210 in the radial direction. For the first core unit 110, the minimum size from the inner circumferential wall 210 is the distance between the first wall surface 111 and the inner circumferential wall 210 in the radial direction. Exemplarily, in some embodiments, the minimum size L1 of the rotor 100 from the inner circumferential wall 210 can be one of 0.2mm, 0.3mm, 0.4mm, and 0.5mm.

[0088] 1 , 8 or 9 , the rotor 100 may have an annular structure and may rotate about a rotation axis. Therefore, the radial direction of the rotor 100 may be understood as a direction perpendicular to the rotation axis.

[0089] In addition, since the air gap magnetic resistance can be similar to a sinusoidal distribution, the maximum and minimum values ​​of the air gap can correspond to the extreme values ​​of the air gap magnetic resistance distribution waveform. Furthermore, through experiments and analysis, it was found that when the minimum size of the air gap and the maximum size of the air gap are within a certain numerical range, it can more accurately ensure that the motor efficiency is high, the harmonic content is low, and the magnetic field distortion rate is low. Specifically, referring to Figure 2, in some embodiments, along the radial direction of the rotor 100, the minimum size L1 of the rotor 100 from the inner circumferential wall 210 and the maximum size L2 of the rotor 100 from the inner circumferential wall 210 satisfy: 0.15≤L1 / L2≤0.75. It should be noted that the above-mentioned L1 / L2 can be understood as the minimum size and the maximum size of the air gap between the rotor 100 and the stator 200, and is not limited to the first air gap 130 or the second air gap 140. For example, in some embodiments, the ratio L1 / L2 of the minimum dimension L1 of the rotor 100 from the inner circumferential wall 210 to the maximum dimension L2 of the rotor 100 from the inner circumferential wall 210 may be one of 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.75.

[0090] It is understood that in some embodiments, the minimum dimension L1 or the maximum dimension L2 may be the distance from a point on the first core unit 110 or the second core unit 120 to the inner circumferential wall 210 along the radial direction of the rotor 100. It should be noted that the minimum dimension L1 and the maximum dimension L2 in the above embodiments are not limited to comparison within the scope of the first core unit 110 and the second core unit 120. In embodiments where the rotor 100 further includes other core units, the above dimensions may also be the distance from a point on the other core units to the inner circumferential wall 210.

[0091] Regarding the arrangement of the core units in the rotor 100. Referring to Figures 1 and 2, in some embodiments, the first core unit 110 and the second core unit 120 can be arranged at intervals. In some embodiments, the first core unit 110 and the second core unit 120 can be disconnected from each other to form the above-mentioned interval arrangement; in other embodiments, the first core unit 110 and the second core unit 120 can be two parts of the rotor 100 as a whole, and the two can be partially connected and partially form an interval. It can be understood that in this embodiment, the gap between the first core unit 110 and the second core unit 120 can be used to separate the core units. Furthermore, in some embodiments, the gap between the first core unit 110 and the second core unit 120 can be used to place the permanent magnet 160 to adapt to the working performance requirements of the rotor 100 corresponding to the motor.

[0092] Referring to Figure 10 , in some embodiments, the rotor 100 may further include a coating 150. In some embodiments, the coating 150 may be a plastic coating applied to the surface or interior of the rotor 100. The plastic coating may be used to connect the various units within the rotor 100 or to connect the rotor 100 with other components. In other embodiments, the coating 150 may be a filler attached to the wall of the rotor 100. The filler may be used to connect or fill the gaps between the core units. To provide a good coating without affecting the overall performance of the motor, the coating 150 may be made of an insulating material, such as plastic or rubber.

[0093] For the embodiment in which the rotor 100 includes a coating 150, referring to FIG10 , in some embodiments, the rotor 100 may further include a permanent magnet 160. A storage space may be defined between the first core unit 110 and the second core unit 120. The permanent magnet 160 may be disposed in the storage space. The storage space may be defined by two circumferentially opposite sidewall surfaces of the first core unit 110 and the second core unit 120. The coating 150 may be coated on one end of the permanent magnet 160 that is radially away from the axis of rotation of the rotor 100. It will be understood that in this embodiment, the coating 150 at least coats the side of the permanent magnet 160 that faces the stator 200, thereby reducing the influence of the exposed portion of the permanent magnet 160 on the overall magnetic field and magnetic flux density of the motor.

[0094] Regarding the embodiment in which the first core unit 110 and the second core unit 120 are arranged at intervals with a gap formed therebetween, referring to FIG10 , to improve the overall connectivity of the rotor 100, the cladding layer 150 can fill the gap between the first core unit 110 and the second core unit 120. Furthermore, the cladding layer 150 can be connected to one end of the first core unit 110 or to one end of the second core unit 120. It is understood that the above-mentioned arrangement of the cladding layer 150 can fill the gap between the core units, thereby improving the integrity of the rotor 100 and reducing magnetic leakage and other interference caused by the gap. On the other hand, based on the improvement of the air gap structure in the embodiment of the present application, the cladding layer 150 can further affect the magnetic flux density curve corresponding to the change in the air gap between the first core unit 110 and the second core unit 120. Specifically, the gap between the cladding layer 150 and the inner circumferential wall 210 can make the change in the air gap between the first core unit 110 and the second core unit 120 smoother, thereby reducing the harmonics caused by the sudden change in the air gap structure. The gap between the cladding layer 150 and the inner circumferential wall 210 corresponds to a cladding magnetic flux density curve. In a rectangular coordinate system, the cladding magnetic flux density curve can be connected to one end of the first magnetic flux density curve and one end of the second magnetic flux density curve. The cladding magnetic flux density curve can adapt to the changing trends of the first magnetic flux density curve and the second magnetic flux density curve and be located between the first magnetic flux density curve and the second magnetic flux density curve. This allows the rotor 100 to form a relatively continuous and smooth magnetic flux density curve within the rotation range between the first core unit 110 and the second core unit 120, thereby reducing the sudden change in magnetic flux density at the gap between the core units and correspondingly reducing harmonics at the gap.

[0095] Referring to Figure 11, in some embodiments, the rotor 100 may include multiple core units arranged adjacent to each other in the circumferential direction around the rotation axis. The shape and structure of each core unit may be the same as the first core unit 110 or the second core unit 120, and each core unit is arranged in a ring array with the rotation axis as the central axis. It is understood that the above-mentioned multiple core units can together form the overall annular shape of the rotor 100. Therefore, for embodiments in which the rotor 100 also includes other core units, the descriptions and definitions of the first core unit 110 or the second core unit 120 in the above-mentioned embodiments can also be further applied to the other core units.

[0096] Corresponding to the embodiment in which the rotor 100 includes a plurality of core units arranged circumferentially adjacent to each other around the rotation axis, the core units of the rotor 100 may have different arrangements. Referring to FIG11 , in an embodiment of the first aspect of the distribution of the core units, the core units may be disconnected from each other. Referring to FIG12 , in an embodiment of the second aspect of the distribution of the core units, the rotor 100 may further include a first magnetic bridge 170 , which is located on a side of each core unit close to the rotation axis, and the first magnetic bridge 170 is used to connect at least two core units. It is understood that in this embodiment, the first magnetic bridge 170 is used to connect the core units, and a plurality of first magnetic bridges 170 may be provided to connect more than two core units. Therefore, in some embodiments, the material of the first magnetic bridge 170 may be plastic, rubber, or other insulating materials, so that the first magnetic bridge 170 acts as a magnetic barrier, reducing magnetic field interference between the core units. In addition, referring to FIG13 , in an embodiment of the third aspect of the distribution of the core units, the rotor 100 may further include a second magnetic bridge 180 . The second magnetic bridge 180 is located on the side of each core unit away from the rotation axis. The second magnetic bridge 180 is used to connect at least two core units. It is understood that the second magnetic bridge 180 is similar to the first magnetic bridge 170 described above, except that the first magnetic bridge 170 is located on the side of each core unit closer to the rotation axis (which can be understood as the inner area formed by the surrounding core units), while the second magnetic bridge 180 is located on the side of each core unit away from the rotation axis (which can be understood as the outer wall area of ​​the surrounding core units). Therefore, the configuration of the second magnetic bridge 180 can refer to the first magnetic bridge 170 described above.

[0097] Referring to Figures 14 and 15 , an embodiment of the second aspect of the present application further provides a stator 300 for use in an electric motor. The motor includes a rotor 400 having an outer peripheral wall 410 disposed around the stator 300. The rotor 400 is disposed within the stator 300. The stator 300 includes a third core unit 310 and a fourth core unit 320. The third core unit 310 and the outer peripheral wall 410 can collectively define a third air gap 330. The third air gap 330 has a third magnetic flux density curve. The fourth core unit 320 and the outer peripheral wall 410 can collectively define a fourth air gap 340. The fourth air gap 340 has a fourth magnetic flux density curve. The third magnetic flux density curve and the fourth magnetic flux density curve do not overlap. It will be understood that the above-described configuration of the stator 300 is similar to the configuration of the rotor 400 in the embodiment of the first aspect of the present application, except that the air gap and structural limitations of the rotor 100 in the embodiment of the first aspect correspond to those of the stator 300 in the embodiment of the second aspect. It is understood that the third core unit 310 in this embodiment may correspond to the first core unit 110 described above, the fourth core unit 320 may correspond to the second core unit 120 described above, the third air gap 330 and the third magnetic flux density may correspond to the first air gap 130 and the first magnetic flux density described above, respectively, and the fourth air gap 340 and the fourth magnetic flux density may correspond to the second air gap 140 and the second magnetic flux density described above, respectively. Therefore, for the configuration and related limitations of the stator 300 and its various rotor units in this embodiment, reference may be made to the relevant description of the rotor 100 provided in the embodiment of the first aspect described above, and no further details will be given here.

[0098] The embodiment of the third aspect of the present application further provides a motor, comprising the rotor 100 of the embodiment of the first aspect of the present application, and the stator 200. It should be noted that the embodiment of this aspect does not limit the form of the stator. Therefore, in some embodiments, the embodiment of this aspect may include the stator 300 of the embodiment of the second aspect described above. That is, in this embodiment, the rotor 100 and the stator 300 both have at least two core units with different air gap structures, and the stator and rotor are both relatively provided with irregular outer wall surfaces. This arrangement can increase the combination diversity of the stator outer profile and the rotor outer profile, and further give full play to the magnetic permeability tempering effect of the uneven air gap.

[0099] An embodiment of the third aspect of the present application further provides a motor, comprising the stator of the embodiment of the second aspect described above, and a rotor.

[0100] The embodiment of the fourth aspect of the present application further provides a motor, comprising the rotor of the embodiment of the first aspect of the present application, and a stator.

[0101] The embodiment of the fifth aspect of the present application further provides a household appliance, comprising the motor of the embodiment of the fourth aspect mentioned above.

[0102] Other contents related to the motor of the third aspect, the motor of the fourth aspect and the household appliance of the fifth aspect can be found in the prior art and will not be described in detail here.

[0103] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. All equivalent structural transformations made based on the contents of the present application specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present application.

Claims

1. A rotor for a motor, the motor comprising a stator, the stator having an inner peripheral wall arranged around the rotor, the rotor being arranged in the stator and being capable of rotating around a rotation axis, the rotor comprising: A first core unit, capable of defining a first air gap together with the inner peripheral wall, wherein the first air gap has a first magnetic flux density curve; as well as A second core unit, capable of defining a second air gap together with the inner peripheral wall, wherein the second air gap has a second magnetic flux density curve; The first magnetic flux density curve does not overlap with the second magnetic flux density curve.

2. The rotor according to claim 1, wherein: The first core unit has a first wall surface facing the inner circumferential wall, and the orthographic projection of the first wall surface on a plane perpendicular to the rotation axis is a first projection. The second core unit has a second wall surface facing the inner circumferential wall, and the orthographic projection of the second wall surface on a plane perpendicular to the rotation axis is a second projection. The shape of the first projection is different from the shape of the second projection, and / or the size of the first projection is different from the size of the second projection.

3. The rotor according to claim 1 or 2, wherein: The first core unit has a first wall surface facing the inner peripheral wall, the orthographic projection of the first wall surface on a plane perpendicular to the rotation axis is a first projection, and the first projection is in a curved shape; and / or, The second core unit has a second wall surface facing the inner peripheral wall, the orthographic projection of the second wall surface on a plane perpendicular to the rotation axis is a second projection, and the second projection is in a curved shape.

4. The rotor according to any one of claims 1 to 3, wherein: The first core unit has a first wall surface facing the inner circumferential wall, the orthographic projection of the first wall surface on a plane perpendicular to the rotation axis is a first projection, the first projection includes a first arc and a second arc, the first arc corresponds to a first center, the second arc corresponds to a second center, and the first center does not coincide with the second center; and / or, The second core unit has a second wall surface facing the inner circumferential wall, and the orthographic projection of the second wall surface on a plane perpendicular to the rotation axis is a second projection. The second projection includes a third arc and a fourth arc. The third arc corresponds to a third center, and the fourth arc corresponds to a fourth center, and the third center does not coincide with the fourth center.

5. The rotor according to any one of claims 1 to 4, wherein: Along the radial direction of the rotor, a minimum dimension L1 of the rotor from the inner circumferential wall satisfies: 0.2 mm ≤ L1 ≤ 0.5 mm.

6. The rotor according to any one of claims 1 to 5, wherein: Along the radial direction of the rotor, a minimum dimension L1 of the rotor from the inner circumferential wall and a maximum dimension L2 of the rotor from the inner circumferential wall satisfy: 0.15≤L1 / L2≤0.

75.

7. The rotor according to any one of claims 1 to 6, wherein: The first core unit and the second core unit are arranged at intervals, and the rotor further includes a coating layer, and the coating layer fills a gap between the first core unit and the second core unit.

8. The rotor according to claim 7, further comprising a permanent magnet, wherein: An accommodation space is defined between the first core unit and the second core unit, the permanent magnet is disposed in the accommodation space, and the coating layer coats one end of the permanent magnet away from the rotation axis along the radial direction of the rotor.

9. The rotor according to any one of claims 1 to 8, wherein: The rotor includes a plurality of core units arranged adjacent to each other in the circumferential direction around the rotation axis. The shape and structure of each core unit are the same as the first core unit or the second core unit. Each core unit is arranged in a ring array with the rotation axis as the central axis.

10. The rotor according to any one of claims 1 to 9, wherein: The rotor comprises a plurality of core units arranged adjacent to each other in the circumferential direction around the rotation axis; The core units are disconnected from each other. or, The rotor further comprises a first magnetic bridge, the first magnetic bridge being located on a side of each of the core units close to the rotation axis, and the first magnetic bridge being used to connect at least two of the core units. or, The rotor further includes a second magnetic bridge, which is located on a side of each of the core units away from the rotation axis, and is used to connect at least two of the core units.

11. A stator for a motor, the motor comprising a rotor, the rotor having an outer peripheral wall arranged around the stator, the rotor being arranged in the stator, the stator comprising: A third core unit, capable of defining a third air gap together with the outer peripheral wall, wherein the third air gap has a third magnetic flux density curve; as well as a fourth core unit, capable of defining a fourth air gap together with the outer peripheral wall, wherein the fourth air gap has a fourth magnetic flux density curve; The third magnetic flux density curve does not overlap with the fourth magnetic flux density curve.

12. A motor, comprising: The stator of claim 11; and Rotor.

13. A motor, comprising: The rotor according to any one of claims 1 to 10; as well as, stator.

14. A household appliance comprising the motor according to claim 13.

Images