Rotor assembly, motor, air supply assembly, and air treatment device

Abstract

Disclosed in the present application are a rotor assembly, a motor, an air supply assembly, and an air treatment device. The rotor assembly (200) comprises a rotor iron core (210) and permanent magnets (230), the rotor iron core (210) comprising an inner iron core (211) and an outer iron core (212), and the outer iron core (212) comprising a plurality of iron core units (2121) arranged around the inner iron core (211). Each iron core unit (2121) comprises a plurality of iron core lamination pieces (213) stacked in a first direction, the first direction (y) being parallel to the axis of rotation (20). In the first direction (y), the thickness dimension of iron core lamination pieces (213) having the smallest thickness is Ts. Two of the plurality of permanent magnets (230) are a first permanent magnet (230a) and a second permanent magnet (230b), the first permanent magnet (230a) having a first wall surface (233) facing the second permanent magnet (230b), and the second permanent magnet (23b) having a second wall surface (234) facing the first permanent magnet (230a), wherein the maximum distance D1 from the first wall surface (233) to the second wall surface (234) and the maximum distance Wm between the two sides of the first wall surface (233) in the circumferential direction satisfy a certain dimensional requirement.

Description

Rotor assembly, motor, air supply assembly and air handling device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202311670627.3 filed on December 6, 2023, entitled “Rotor assembly, motor, air supply assembly and air treatment device”. The entire contents of the above patent application are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of electric drive devices, and in particular to a rotor assembly, a motor, an air supply assembly, and an air handling device. Background Art

[0004] In a split rotor assembly, the rotor core comprises an inner core and an outer core that are disconnected from each other. The outer core comprises multiple core units arranged around the inner core. The core units are disconnected along the rotor assembly's rotational axis, with a permanent magnet positioned between each two core units. In related art, magnetic flux leakage is prone to occur at the ends of the core units near the rotational axis, reducing the motor's power density.

[0005] Summary of the Invention

[0006] The main purpose of this application is to propose a rotor assembly, a motor, an air supply assembly and an air handling device to at least partially solve one of the above technical problems.

[0007] An embodiment of a first aspect of the present application provides a rotor assembly configured to rotate about a rotation axis, wherein the rotor assembly includes a rotor core and N permanent magnets.

[0008] The rotor core includes an inner core and an outer core disconnected from the inner core. The outer core includes a plurality of core units disconnected from each other. Each of the core units is distributed around the inner core along the circumference of the rotation axis. Each of the core units includes a plurality of core laminations stacked along a first direction, and the first direction is parallel to the rotation axis. Along the first direction, the thickness dimension of the core lamination with the smallest thickness is Ts. An installation groove is provided between each two adjacent core units.

[0009] N≥4, each of the permanent magnets is arranged in each of the mounting slots in a one-to-one correspondence, two of the permanent magnets are a first permanent magnet and a second permanent magnet, the first permanent magnet and the second permanent magnet are distributed on opposite sides of the rotation axis along a second direction, the second direction is perpendicular to the rotation axis, the first permanent magnet includes a first wall facing the second permanent magnet, and the second permanent magnet includes a second wall facing the first permanent magnet.

[0010] The maximum distance D1 between the first wall surface and the second wall surface and the maximum distance Wm between the two sides of the first wall surface along the circumferential direction satisfy:

[0011] Among them: 1≤K≤5.

[0012] In some embodiments, the inner core is in a ring shape arranged around the rotation axis, and the inner core includes a first inner peripheral wall close to the rotation axis and a first outer peripheral wall away from the rotation axis. Along the second direction, the maximum distance Wr between the first inner peripheral wall and the first outer peripheral wall satisfies: Wr≥2×Ts.

[0013] In some embodiments, along the second direction, a maximum distance Wr between the first inner peripheral wall and the first outer peripheral wall satisfies: Wr≥2.5 mm.

[0014] In some embodiments, along the radial direction of the rotor assembly, the minimum distance Wa between each of the core units and the inner core satisfies: Wa≥2×Ts.

[0015] In some embodiments, along the radial direction of the rotor assembly, a minimum distance Wa between each of the core units and the inner core satisfies: Wa≥2.5 mm.

[0016] In some embodiments, the core unit has a third wall located on one side along the circumferential direction, and the third wall is provided with a limiting protrusion, which is suitable for abutting the side wall of the permanent magnet facing away from or facing the rotation axis; the maximum distance L1 from the end of the limiting protrusion away from the third wall to the third wall satisfies: L1≥Ts.

[0017] In some embodiments, a minimum distance L2 between a side wall of the limiting protrusion facing the rotation axis and a side wall away from the rotation axis satisfies: L2 ≥ Ts.

[0018] In some embodiments, two of the core units are a first core unit and a second core unit, and the mounting groove is defined between the first core unit and the second core unit; the first core unit includes a first end facing away from the rotation axis, and the second core unit includes a second end facing away from the rotation axis, and the minimum distance L3 between the first end and the second end satisfies: L3≤0.6×Wm; or 0.4×Wm≤L3≤0.6×Wm.

[0019] In some embodiments, two of the core units are a first core unit and a second core unit, and the mounting groove is defined between the first core unit and the second core unit; the first core unit has a fourth wall facing the second core unit, and the fourth wall is provided with a first limiting protrusion and a second limiting protrusion, and the second core unit has a fifth wall facing the first core unit, and the fifth wall is provided with a third limiting protrusion and a fourth limiting protrusion; the first limiting protrusion and the third limiting protrusion are suitable for abutting the wall of the permanent magnet away from the rotation axis, and the second limiting protrusion and the fourth limiting protrusion are suitable for abutting the wall of the permanent magnet facing the rotation axis; the minimum distance between the first limiting protrusion and the third limiting protrusion is L4, and the minimum distance between the second limiting protrusion and the fourth limiting protrusion is L5; wherein, L5≥L4.

[0020] In some embodiments, the first limiting protrusion is located at the end of the fourth wall away from the rotation axis, the second limiting protrusion is located at the end of the fourth wall close to the rotation axis, the third limiting protrusion is located at the end of the fifth wall away from the rotation axis, and the fourth limiting protrusion is located at the end of the fifth wall close to the rotation axis.

[0021] In some embodiments, the permanent magnet extends out of one or both ends of the mounting slot along the first direction.

[0022] In some embodiments, the core unit has a third wall surface that is in contact with the permanent magnet, and the third wall surface is provided with a first injection molding groove, and the first injection molding groove penetrates the core unit along the first direction.

[0023] In some embodiments, the rotor assembly further includes a first injection-molded portion, the first injection-molded portion connecting the outer iron core and the inner iron core, and the injection-molded portion fills a gap between the outer iron core and the inner iron core.

[0024] An embodiment of the second aspect of the present application further provides a motor, comprising:

[0025] A rotor assembly as described in any one of the above; and

[0026] The stator assembly is arranged around the rotor assembly.

[0027] In some embodiments, the stator assembly includes a stator core and a coil winding connected to the stator core, the stator core includes a second outer peripheral wall, and the second outer peripheral wall is provided with a second injection molding groove.

[0028] In some embodiments, the stator assembly further includes a second injection-molded portion, wherein the second injection-molded portion wraps the stator core and the coil winding.

[0029] An embodiment of the third aspect of the present application further provides an air supply assembly, comprising the motor described above.

[0030] An embodiment of the fourth aspect of the present application further provides an air treatment device, comprising the above-mentioned air supply assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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.

[0032] FIG1 is a side view schematic diagram of a combination of an iron core unit and a permanent magnet in a rotor assembly in one embodiment of the present application; wherein the viewing angle is parallel to a first direction;

[0033] FIG2 is a side view schematic diagram of a permanent magnet assembly in one embodiment of the present application; wherein the viewing angle is parallel to the first direction;

[0034] FIG3 is a side view schematic diagram of an iron core unit in an embodiment of the present application; wherein the viewing angle is parallel to the first direction;

[0035] FIG4 is a partial enlarged schematic diagram of point A1 in FIG3 ;

[0036] FIG5 is a partial enlarged schematic diagram of point A2 in FIG3 ;

[0037] FIG6 is a schematic side view of an iron core lamination according to an embodiment of the present application; wherein the viewing angle is parallel to the first direction;

[0038] FIG7 is a partial enlarged schematic diagram of A3 in FIG6;

[0039] FIG8 is a perspective schematic diagram of an iron core lamination in one embodiment of the present application;

[0040] FIG9 is a schematic side view of the inner core in one embodiment of the present application; wherein the viewing angle is parallel to the first direction;

[0041] FIG10 is a perspective schematic diagram of a rotor assembly in one embodiment of the present application;

[0042] FIG11 is a side view schematic diagram of the rotor core, stator core, and permanent magnet assembly of a motor in one embodiment of the present application; wherein the viewing angle is parallel to the first direction;

[0043] FIG12 is a schematic side view of a stator core according to an embodiment of the present application; wherein the viewing angle is parallel to the first direction;

[0044] FIG13 is a partial enlarged schematic diagram of A4 in FIG12;

[0045] FIG14 is a bar graph showing the relationship between L3 / Wm and the per-unit value of the no-load back EMF, and a line graph showing the relationship between L3 / Wm and the demagnetization rate in one embodiment of the present application;

[0046] FIG15 is a line graph showing the relationship between Wm and demagnetization current in one embodiment of the present application; and

[0047] FIG16 is a graph showing D2 / D3 and motor efficiency in one embodiment of the present application, wherein the motor high-speed heavy-load efficiency curve, low-speed light-load efficiency curve, and comprehensive average efficiency curve are shown.

[0048] Description of Figure Numbers:

[0049] Motor 10;

[0050] stator assembly 100;

[0051] stator core 110 ; yoke 111 ; second injection molding groove 1111 ; stopper 1112 ; tooth 112 ; third end 1121 ; fourth end 1122 ; tenth wall 1123 ; eleventh wall 1124 ; boundary line 1125 ; first tooth 112a ; second tooth 112b ;

[0052] Rotor assembly 200;

[0053] Rotor core 210; inner core 211; first inner circumferential wall 2111; first outer circumferential wall 2112; outer core 212; core unit 2121; first end 21211; second end 21212; first limiting protrusion 21213; third limiting protrusion 21214; second limiting protrusion 21215; fourth limiting protrusion 21216; first injection molding groove 21217; core lamination 213; mounting groove 214; third wall 215; fourth wall 216; fifth wall 217; limiting protrusion 218; first core unit 2121a; second core unit 2121b;

[0054] First injection molding part 220;

[0055] Permanent magnet 230; eighth wall 231; ninth wall 232; first wall 233; second wall 234; sixth wall 235; seventh wall 236; first permanent magnet 230a; second permanent magnet 230b;

[0056] Axis of rotation 20;

[0057] First direction y;

[0058] The second direction x;

[0059] Circumferential m.

[0060] 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. DETAILED DESCRIPTION

[0061] 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.

[0062] In a split rotor assembly, the rotor core comprises an inner core and an outer core that are disconnected from each other. The outer core comprises multiple core units arranged around the inner core. The core units are disconnected along the rotor assembly's rotational axis, with a permanent magnet positioned between each two core units. In related art, magnetic flux leakage is prone to occur at the ends of the core units near the rotational axis, reducing the motor's power density.

[0063] In view of this, referring to Figures 1-16 , some embodiments of the present application provide a rotor assembly 200 configured to rotate about a rotation axis 20. The rotor assembly 200 includes a rotor core 210 and N permanent magnets 230 , where N is greater than or equal to 4. Specifically, N can be 4, 6, 8, 10, or 12. In this embodiment, referring to Figures 1-5 , the number of permanent magnets 230 is specifically 10.

[0064] Referring to Figures 1-3, 6, and 8, the rotor core 210 includes an inner core 211 and an outer core 212 disconnected from the inner core 211. It should be noted that "the inner core 211 and the outer core 212 are disconnected" only means that the inner core 211 and the outer core 212 are not in direct contact, and does not mean that the inner core 211 and the outer core 212 are not connected at all. In this embodiment, the outer core 212 and the inner core 211 are indirectly connected via the first injection molded portion 220. The outer core 212 includes a plurality of disconnected core units 2121. The core units 2121 are not in direct contact. In this embodiment, the core units 2121 are indirectly connected via the permanent magnets 230 and / or the first injection molded portion 220. The core units 2121 are arranged around the inner core 211 along the circumferential direction m of the rotation axis 20. Specifically, the core units 2121 are arranged in a circular array with the rotation axis 20 as the center axis, and the distance between each adjacent core unit 2121 along the circumferential direction m is equal. Each core unit 2121 includes a plurality of core laminations 213 stacked along a first direction y, parallel to the rotation axis 20. Along the first direction y, the smallest core lamination 213 has a thickness Ts. That is, when the thicknesses of each core lamination 213 along the first direction y are equal, Ts is the thickness of each core lamination 213 along the first direction y. When at least two core laminations 213 have unequal thicknesses along the first direction y, each core lamination 213 has a thickness along the first direction y, and Ts is the thickness of the smallest core lamination 213.

[0065] A mounting slot 214 is provided between each two adjacent core units 2121, and each permanent magnet 230 is provided in each mounting slot 214 in a one-to-one correspondence. It should be noted that, in this embodiment, a permanent magnet 230 provided in a single mounting slot 214 is defined as a permanent magnet 230. In some embodiments, a permanent magnet 230 may be an independent individual. In other embodiments, a permanent magnet 230 may include a plurality of permanent magnet monomers, and each permanent magnet monomer is stacked along the first direction y. Two of the permanent magnets 230 are a first permanent magnet 230a and a second permanent magnet 230b, and the first permanent magnet 230a and the second permanent magnet 230b are distributed on opposite sides of the rotation axis 20 along the second direction x, and the second direction x is perpendicular to the rotation axis 20. It should be noted that the "first permanent magnet 230a" and "second permanent magnet 230b" referred to in this application are any two permanent magnets 230 located on radially opposite sides of the rotor assembly 200. Therefore, in the embodiment shown in FIG2 , there are five pairs of permanent magnets 230, and the two permanent magnets 230 in each pair of permanent magnets 230 can be referred to as the "first permanent magnet 230a" and the "second permanent magnet 230b." In other embodiments, for example, when the rotor assembly 200 includes twelve permanent magnets 230, it has six pairs of "first permanent magnet 230a" and "second permanent magnet 230b." For ease of description, the following uses the "first permanent magnet 230a" and "second permanent magnet 230b" in one pair as an example. The first permanent magnet 230a includes a first wall 233 facing the second permanent magnet 230b, and the second permanent magnet 230b includes a second wall 234 facing the first permanent magnet 230a. The maximum distance D1 between the first wall surface 233 and the second wall surface 234 and the maximum distance Wm between the two sides of the first wall surface 233 along the circumferential direction m satisfy the following conditions:

[0066] The above formula is equivalent to:

[0067] Among them, let:

[0068] Therefore:

[0069] Wm=T1-K×Ts;

[0070] Wherein: 1≤K≤5. For example, K can be 1, 2, 3, 4 or 5, etc. T1 is basically equal to the theoretical upper limit size of the first wall 233. 1≤K≤5, that is, the maximum spacing Wm on both sides of the first wall 233 along the circumferential direction m is less than its theoretical maximum size minus one to five times the minimum wall thickness of the core lamination 213. In this solution, the leakage flux of the permanent magnet 230 at the two end support positions of the outer core 212 close to the rotating axis 20 is effectively limited, the power density of the motor 10 is improved, and the cost of the motor 10 is reduced. By constraining the width of one end of the permanent magnet 230 close to the rotating axis 20, the low-speed and light-load performance of the motor 10 and the anti-demagnetization strength of the permanent magnet 230 are improved, and the motor 10 achieves high efficiency and high reliability operation.

[0071] It should be noted that since the first permanent magnet 230a can be any one of the permanent magnets 230, in some embodiments, the maximum spacing between the walls of all permanent magnets 230 facing the rotation axis 20 along the circumferential direction m can be Wm. Furthermore, the first permanent magnet 230a includes a sixth wall 235 and a seventh wall 236 that are opposed to each other along the circumferential direction m. When the sixth wall 235 and the seventh wall 236 are planar walls and arranged parallel to each other, the spacing between the sixth wall 235 and the seventh wall 236 is equal to the maximum spacing Wm between the first wall 233 along the circumferential direction m. When the sixth wall 235 and the seventh wall 236 are not parallel or both are not planar walls, the maximum spacing between the end of the sixth wall 235 near the rotation axis 20 and the end of the seventh wall 236 near the rotation axis 20 is equal to the maximum spacing Wm between the first wall 233 along the circumferential direction m. When chamfers are respectively provided between the first wall 233 and the sixth wall 235 and the seventh wall 236, the maximum distance between the side of the chamfer between the first wall 233 and the sixth wall 235 close to the sixth wall 235 and the side of the chamfer between the first wall 233 and the seventh wall 236 close to the seventh wall 236 is defined as Wm.

[0072] Referring to Figures 2-5 and 9 , in some embodiments, the inner core 211 is annular and arranged around the rotation axis 20. The inner core 211 includes a first inner circumferential wall 2111 proximal to the rotation axis 20 and a first outer circumferential wall 2112 facing away from the rotation axis 20. Along the first direction y, the maximum distance Wr between the first inner circumferential wall 2111 and the first outer circumferential wall 2112 of the inner core 211 satisfies the following: Wr ≥ 2 × Ts. For example, Wr can be 2Ts, 2.2Ts, 2.4Ts, 2.6Ts, 2.8Ts, or 3Ts. In this embodiment, Wr is equal to the maximum annular width of the inner core 211 along the second direction x. A larger Wr reduces the gap between the inner core 211 and the outer core 212, making injection molding difficult and reducing the connection stability between the inner core 211 and the outer core 212. When Wr is small, the inner core 211 provides poor support for the rotating shaft passing through it. In this embodiment, when Wr ≥ 2 × Ts, the gap between the inner core 211 and the outer core 212 can be increased, thereby increasing the injection molding space and improving the connection stability between the inner core 211 and the outer core 212; it can also improve the support stability of the rotating shaft.

[0073] Referring to Figures 2-5 and 9 , in some embodiments, the inner core 211 is annular and arranged around the rotation axis 20. The inner core 211 includes a first inner circumferential wall 2111 proximal to the rotation axis 20 and a first outer circumferential wall 2112 facing away from the rotation axis 20. Along the first direction y, the maximum distance Wr between the first inner circumferential wall 2111 and the first outer circumferential wall 2112 satisfies the following: Wr ≥ 2.5 mm. For example, Wr can be 2.5 mm, 2.7 mm, 3 mm, 3.2 mm, 3.5 mm, or 3.7 mm. This solution not only increases the gap between the inner core 211 and the outer core 212, thereby increasing the injection molding space and improving the connection stability between the inner core 211 and the outer core 212, but also improves the support stability of the rotating shaft. In further embodiments, Wr can also satisfy Wr ≥ 2 × Ts.

[0074] Referring to Figures 2-5 and 9 , in some embodiments, along the radial direction of the rotor assembly 200 , the minimum distance Wa between each core unit 2121 and the inner core 211 satisfies the following: Wa ≥ 2 × Ts. For example, Wa can be 2Ts, 2.2Ts, 2.4Ts, 2.6Ts, 2.8Ts, or 3Ts. This solution can, on the one hand, increase the gap between the inner core 211 and the outer core 212, thereby increasing the injection molding space and improving the connection stability between the inner core 211 and the outer core 212; on the other hand, it can also improve the support stability of the rotating shaft.

[0075] Referring to Figures 2 to 5 and Figure 9, in some embodiments, along the radial direction of the rotor assembly 200, the minimum distance Wa between each core unit 2121 and the inner core 211 satisfies: Wa ≥ 2.5 mm. For example, Wa can be 2.5 mm, 2.7 mm, 3 mm, 3.2 mm, 3.5 mm or 3.7 mm, etc. In this solution, on the one hand, the gap between the inner core 211 and the outer core 212 can be increased, thereby increasing the injection molding space and improving the connection stability between the inner core 211 and the outer core 212; on the other hand, it can also improve the support stability for the rotating shaft. In a further embodiment, Wa can also simultaneously satisfy Wa ≥ 2 × Ts.

[0076] 3-7 , in some embodiments, in order to form a stable positioning for the permanent magnet 230, the core unit 2121 has a third wall 215 located on one side along the circumferential direction m, and the third wall 215 is provided with a limiting protrusion 218. The limiting protrusion 218 is suitable for abutting the side wall of the permanent magnet 230 away from or facing the rotation axis 20. Specifically, in one embodiment, the limiting protrusion 218 can be provided on the side of the third wall 215 away from the rotation axis 20 (in this case, the limiting protrusion 218 is referred to as the first limiting protrusion 21213 or the third limiting protrusion 21214 below), thereby being used to abut the side of the permanent magnet 230 away from the rotation axis 20 to limit the position of the permanent magnet 230 in a direction away from the rotation axis 20. In another embodiment, a limiting protrusion 218 may be provided on a side of the third wall surface 215 close to the rotation axis 20 and abut against the wall surface of the permanent magnet 230 facing the rotation axis 20 (in this case, the limiting protrusion 218 is referred to as the second limiting protrusion 21215 or the fourth limiting protrusion 21216 below) to limit the displacement of the permanent magnet 230 toward the rotation axis 20. In yet another embodiment, a limiting protrusion 218 may be provided on both the side of the third wall surface 215 close to the rotation axis 20 and the side facing away from the rotation axis 20, respectively, with the two limiting protrusions 218 correspondingly abutting against the wall surfaces of the permanent magnet 230 on both sides of the radial direction of the rotor assembly 200.

[0077] When the length of the limiting protrusion 218 extending from the third wall 215 is too long, the magnetic flux leakage of the rotor assembly 200 will increase. When the length of the limiting protrusion 218 extending from the third wall 215 is too short, the limiting effect of the limiting protrusion 218 on the permanent magnet 230 is poor. In view of this, referring to FIG7 , in some embodiments, the maximum distance L1 from the end of the limiting protrusion 218 away from the third wall 215 to the third wall 215 satisfies: L1 ≥ Ts. Exemplarily, L1 can be Ts, 1.2Ts, 1.3Ts, 1.4Ts, 1.5Ts or 1.6Ts, etc. In this solution, the limiting protrusion 218 can not only effectively limit the permanent magnet 230, but also reduce the magnetic flux leakage of the rotor assembly 200.

[0078] When the radial length of the limiting protrusion 218 is too long, the magnetic flux leakage of the rotor assembly 200 will increase. When the radial length of the limiting protrusion 218 is too short, the strength and rigidity of the limiting protrusion 218 are poor. In view of this, referring to FIG7 , in some embodiments, the minimum spacing L2 between the side wall of the limiting protrusion 218 facing the rotation axis 20 and the side wall away from the rotation axis 20 satisfies: L2 ≥ Ts. For example, L2 can be Ts, 1.2Ts, 1.3Ts, 1.4Ts, 1.5Ts or 1.6Ts, etc. In this solution, the limiting protrusion 218 has both high strength and rigidity and reduces the magnetic flux leakage of the rotor assembly 200.

[0079] 2-5 , in some embodiments, two of the core units 2121 are a first core unit 2121a and a second core unit 2121b . A mounting slot 214 is defined between the first core unit 2121a and the second core unit 2121b . In other words, the first core unit 2121a and the second core unit 2121b are adjacent to each other and spaced apart along the circumferential direction m. It should be noted that the difference in naming "first core unit 2121a" and "second core unit 2121b" is only for differentiation; any two core units 2121 adjacent to each other along the circumferential direction m in the core units 2121 may be referred to as the first core unit 2121a and the second core unit 2121b . The first core unit 2121a includes a first end 21211 that faces away from the rotation axis 20, and the second core unit 2121b includes a second end 21212 that faces away from the rotation axis 20. The minimum spacing L3 between the first end 21211 and the second end 21212 satisfies the following: L3 ≤ 0.6×Wm. For example, L3 can be 0.2Wm, 0.3Wm, 0.4Wm, 0.5Wm, or 0.6Wm. Specifically, referring to FIG14 , when L3 / Wm gradually increases from 0 to 1, the demagnetization rate of the motor 10 under the same demagnetization current gradually increases, thereby reducing the efficiency of the motor 10. Therefore, L3 / Wm cannot be too large. After demonstration, when L3 ≤ 0.6×Wm, the demagnetization rate of the motor 10 can be reduced, thereby improving the efficiency of the motor 10.

[0080] In a further embodiment, the minimum spacing L3 between the first end 21211 and the second end 21212 satisfies: 0.4×Wm≤L3≤0.6×Wm. For example, L3 can be 0.4Wm, 0.45Wm, 0.5Wm, 0.55Wm or 0.6Wm, etc. Specifically, referring to FIG14 , when L3 / Wm is 0, the no-load back EMF per unit value is set to 1. When L3 / Wm gradually increases from 0 to 1, the no-load back EMF per unit value gradually increases. However, the demagnetization rate of the motor 10 under the same demagnetization current gradually increases. Therefore, L3 / Wm cannot be too large or too small. If L3 / Wm is too large, the demagnetization rate of the motor 10 will be large. If L3 / Wm is too small, the magnetic leakage of the motor 10 will be too large and the efficiency of the motor 10 will be reduced. It has been demonstrated that when 0.4×Wm≤L3≤0.6×Wm, the demagnetization rate of the motor 10 is low and the per-unit value of the no-load back electromotive force is high, so that the efficiency of the motor 10 is high.

[0081] 2-5 , in some embodiments, two of the core units 2121 are a first core unit 2121a and a second core unit 2121b , with a mounting slot 214 defined between the first core unit 2121a and the second core unit 2121b . The first core unit 2121a has a fourth wall 216 facing the second core unit 2121b . The fourth wall 216 is provided with at least two retaining protrusions 218 . For ease of distinction, the two retaining protrusions 218 are designated as a first retaining protrusion 21213 and a second retaining protrusion 21215 , respectively. The second core unit 2121b has a fifth wall 217 facing the first core unit 2121a . The fifth wall 217 is provided with at least two retaining protrusions 218 . For ease of distinction, the two retaining protrusions 218 are designated as a third retaining protrusion 21214 and a fourth retaining protrusion 21216 , respectively. The first limiting protrusion 21213 and the third limiting protrusion 21214 are adapted to abut against the wall surface of the permanent magnet 230 facing away from the rotation axis 20, and the second limiting protrusion 21215 and the fourth limiting protrusion 21216 are adapted to abut against the wall surface of the permanent magnet 230 facing the rotation axis 20. That is, the first limiting protrusion 21213, the second limiting protrusion 21215, the third limiting protrusion 21214, and the fourth limiting protrusion 21216 jointly limit the position of the permanent magnet 230. Specifically, the minimum spacing between the first limiting protrusion 21213 and the third limiting protrusion 21214 is L4, and the minimum spacing between the second limiting protrusion 21215 and the fourth limiting protrusion 21216 is L5, where L5 ≥ L4. In this solution, the magnetic leakage of the outer iron core 212 at one end close to the rotation axis 20 can be reduced, thereby improving the efficiency of the motor 10. At the same time, it can also improve the limiting effect of the permanent magnet 230, preventing the rotor assembly 200 from moving in a direction away from the rotation axis 20 relative to the rotor iron core 210 due to the action of centrifugal force when rotating.

[0082] Referring to Figures 2-5 , in some embodiments, the first limiting protrusion 21213 is located at the end of the fourth wall 216 facing away from the rotation axis 20, the second limiting protrusion 21215 is located at the end of the fourth wall 216 closer to the rotation axis 20, the third limiting protrusion 21214 is located at the end of the fifth wall 217 facing away from the rotation axis 20, and the fourth limiting protrusion 21216 is located at the end of the fifth wall 217 closer to the rotation axis 20. In this embodiment, the minimum distance L4 between the first limiting protrusion 21213 and the third limiting protrusion 21214 is equal to the minimum distance L3 between the first end 21211 and the second end 21212. When L3 is too small, magnetic flux leakage is reduced compared to a structure without the limiting protrusion 218.

[0083] In some embodiments, the permanent magnet 230 extends out of one or both ends of the mounting slot 214 along the first direction y. This embodiment can improve the utilization rate of the magnetic conductive material.

[0084] 2-6 , in some embodiments, the core unit 2121 has a third wall 215 that mates with the permanent magnet 230. The third wall 215 is provided with a first injection molding groove 21217 that extends through the core unit 2121 along a first direction y. In some embodiments, the rotor assembly 200 further includes a first injection molding portion 220 that connects the outer core 212 and the inner core 211 and fills the gap between the outer core 212 and the inner core 211. The first injection molding portion 220 can also fill the first injection molding groove 21217, thereby further stabilizing the connection between the core laminations 213.

[0085] Referring to Figures 2-6, in some embodiments, the core laminations 213 are provided with a limiting portion 1112. The limiting portion 1112 forms a recess on one side wall of the core lamination 213 along a first direction y and a protrusion on the other side wall of the core lamination 213 along the first direction y, where the first direction y is parallel to the rotation axis 20. In this embodiment, when multiple core laminations 213 are stacked in a direction parallel to the rotation axis 20, the protrusions of other core laminations 213 on one side of the current core lamination 213 extend into the recess of the current core lamination 213, and the protrusions on the other side of the current core lamination 213 extend into the recess of other core laminations 213, thereby making the relative positions of the core laminations 213 along the circumferential direction m more stable and preventing relative movement of the core laminations 213 along the circumferential direction m. In other embodiments, each lamination of the stator core 110 may also be provided with a limiting portion 1112, which will not be described in detail here.

[0086] The AC loss and iron loss of the stator winding of the motor are different under heavy load and light load, which makes the efficiency of the motor different under heavy load and light load. In the related art, the motor either focuses on the efficiency under heavy load (the actual working load is greater than 80% of the rated load), so the efficiency is lower under light load (the actual working load is less than 30% of the rated load); or focuses on the efficiency under light load, so the efficiency is lower under heavy load. When the motor has both heavy load and light load conditions, no matter whether the motor design focuses more on heavy load conditions or light load conditions, its overall comprehensive efficiency when working under various conditions is not ideal, that is, when the motor design focuses more on heavy load conditions, due to its lower efficiency under light load conditions, the overall comprehensive efficiency of the motor is poor; when the motor design focuses more on light load conditions, due to its lower efficiency under heavy load conditions, the overall comprehensive efficiency of the motor is poor.

[0087] In summary, in order to make the overall comprehensive power of the motor better under heavy load conditions and light load conditions, it is necessary to balance the AC loss and iron loss of the stator winding of the motor under different working conditions. However, in the related art, the specific means to achieve the balance between the two are not clear. After demonstration and analysis, the applicant found that the ratio of the outer diameter of the motor's magnet to the outer diameter of the stator core is correlated with the overall comprehensive power of the motor. That is, the present application first provides an idea for balancing the AC loss and iron loss of the motor's stator winding, and under the guidance of this idea, provides a specific means to achieve the balance of the AC loss and iron loss of the motor's stator winding through experimental demonstration, thereby achieving a technical effect of better overall efficiency when the motor works under different working conditions.

[0088] In view of this, an embodiment of the second aspect of the present application further provides a motor 10 , which includes the rotor assembly 200 of any one of the above items and a stator assembly 100 , wherein the stator assembly 100 is arranged around the rotor assembly 200 .

[0089] 1-2 and 11-13 , in some embodiments, the first permanent magnet 230a has an eighth wall 231 facing away from the second permanent magnet 230b, the second permanent magnet 230b has a ninth wall 232 facing away from the first permanent magnet 230a, and the minimum distance between the eighth wall 231 and the ninth wall 232 is D2. Specifically, the eighth wall 231 and the ninth wall 232 can be planar walls and parallel to each other. In this case, the minimum distance between the eighth wall 231 and the ninth wall 232 is D2, which is the distance from any point on the eighth wall 231 to the ninth wall 232, or the distance from any point on the ninth wall 232 to the eighth wall 231. In other embodiments, the eighth wall surface 231 and the ninth wall surface 232 are plane walls and there may be a small angle between the two (the existence of the angle may be due to design requirements, or may be formed by processing errors or assembly errors); or the eighth wall surface 231 and the ninth wall surface 232 may also be arc surfaces. In this case, D2 is the minimum distance between the eighth wall surface 231 and the ninth wall surface 232 along the radial direction of the rotor assembly 200.

[0090] The stator assembly 100 is arranged around the rotor assembly 200, and the stator assembly 100 includes a stator core 110. Specifically, the stator core 110 includes a yoke 111 and a plurality of teeth 112. The yoke 111 is annular and is arranged around the outside of the rotor assembly 200. Each tooth 112 is provided between the yoke 111 and the rotor core 210 and is connected to the yoke 111. Each tooth 112 is distributed around the outside of the rotor assembly 200, with one end of each tooth 112 connected to the inner circumferential wall of the yoke 111 and the other end spaced apart from the rotor assembly 200. Specifically, each tooth 112 is arranged in a circular array with the rotation axis 20 as the central axis, and the spacing between each adjacent two teeth 112 along the circumferential direction m of the rotation axis 20 is the same. The stator assembly 100 may also include a coil winding, which is arranged around each tooth 112.

[0091] The maximum outer diameter of the stator core 110 is D3. In some embodiments, the maximum outer diameter of the stator core 110 may be the maximum outer diameter of the outer peripheral wall of the yoke 111; in other embodiments, when the outer peripheral wall of the yoke 111 is also provided with other structures, for example, when the outer peripheral wall of the yoke 111 is also connected to the outer teeth, the maximum outer diameter of the stator core 110 is the maximum outer diameter of the outer teeth. In this embodiment, the maximum outer diameter of the stator is taken as an example to illustrate the maximum outer diameter of the yoke 111. When the outer peripheral wall of the stator core 110 is a regular circle, D3 is the diameter of the outer peripheral wall of the stator core 110. When the outer peripheral wall of the stator core 110 is an irregular ring, D3 is the maximum dimension of the outer peripheral wall of the stator core 110 in a direction perpendicular to the rotation axis 20. During actual measurement, a vernier caliper can be used to abut both sides of the stator core 110 in a direction perpendicular to the rotation axis 20, and the stator assembly 100 can be rotated relative to the vernier caliper with the rotation axis 20 as the center. At this time, the maximum degree displayed by the vernier caliper is the maximum outer diameter D3 of the stator core 110.

[0092] After demonstration, it is found that the ratio of D2 / D3 is correlated with the distribution of AC loss and iron loss of the stator winding of the motor 10. Specifically, when the ratio of D2 / D3 is small, the iron loss may account for a small proportion. When the ratio of D2 / D3 is large, the AC loss of the stator winding may account for a relatively small proportion. Only when D2 / D3 is within a certain range, the distribution of AC loss and iron loss of the stator winding is optimal, and the efficiency of the motor 10 is also the highest at this time. When the AC loss and iron loss of the stator winding of the motor 10 are distributed better, the overall working efficiency of the motor 10 is better under heavy load conditions and light load conditions. Referring to Figures 1-2, Figures 11-13, and Figure 16, in this embodiment, by changing the ratio of D2 / D3, the working efficiency of the motor 10 under heavy load conditions and light load conditions are obtained respectively. After verification and analysis, it was found that when 0.5 ≤ D2 / D3 ≤ 0.6, for example, D2 / D3 can be 0.5, 0.52, 0.54, 0.56, 0.58, or 0.6. When 0.5 ≤ D2 / D3 ≤ 0.6, the magnetic field distribution in the permanent magnet motor 10 can be optimized, minimizing the AC loss and iron loss of the stator winding of the motor 10 under various operating conditions. This results in a better overall efficiency of the motor 10 when the motor 10 operates under both heavy and light load conditions. Referring to Figures 1-2, 11-13, and 16, when D2 / D3 is between 0.53 and 0.55, the heavy load efficiency of the motor 10 increases, while the light load efficiency of the motor 10 decreases. When D2 / D3 is between 0.61 and 0.63, the heavy load power of the motor 10 decreases slightly, while the light load power of the motor 10 decreases. In summary, the best comprehensive power occurs in the middle section between D2 / D3 of 0.53 and 0.63. After demonstration, it is found that when 0.5≤D2 / D3≤0.6, the comprehensive power of the motor 10 is best.

[0093] To further improve the overall power of the motor 10 , in some embodiments, 0.53≤D2 / D3≤0.57, for example, D2 / D3 may be 0.53, 0.54, 0.55, 0.56, or 0.57, etc. When 0.53≤D2 / D3≤0.57, the overall power of the motor 10 is better.

[0094] Referring to Figures 1-2, 11-13, and 16, in some embodiments, 40mm≤D2≤100mm, for example, D2 is 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, or 100mm. When 40mm≤D2≤100mm, the ratio D1 / D2 can be more closely related to the overall efficiency of the motor 10, thereby improving the overall efficiency of the motor 10 and making the prediction of improving the overall efficiency of the motor 10 more accurate. Preferably, 60mm≤D2≤80mm. For example, D2 is 60mm, 65mm, 70mm, 75mm, or 80mm. When 60mm≤D2≤80mm, the ratio D2 / D3 can be more closely related to the overall efficiency of the motor 10, thereby further improving the overall efficiency of the motor 10 and making the prediction of improving the overall efficiency of the motor 10 more accurate.

[0095] To evenly distribute the iron loss of the motor 10 across the teeth 112 and yoke 111 of the motor 10, the motor 10 is further optimized. Referring to Figures 1-2, 11-13, and 16, in some embodiments, the number of teeth 112 of the stator core 110 is X, where X ≥ 6. The number X of teeth 112 may be greater than the number of permanent magnets 230. Each tooth 112 has a tenth wall 1123 and an eleventh wall 1124 that are arranged opposite to each other along the circumferential direction m of the rotation axis 20. The minimum distance Wt between the tenth wall 1123 and the eleventh wall 1124 satisfies the following:

[0096] Specifically, the above formula is equivalent to:

[0097] Among them, let:

[0098] Therefore:

[0099] T2 is equal to the theoretical maximum arrangement space for a single tooth 112 at the radially central position of the stator assembly 100, along the circumferential direction m. That is, Wt is between T2 / 4 and 2T2 / 3 of the theoretical maximum arrangement space for the central position of the tooth 112. Specifically, Wt can be T2 / 4, T2 / 3, 5T2 / 12, T2 / 2, 7T2 / 12, or 2T2 / 3. This solution evenly distributes the iron loss of the stator assembly 100 across the teeth 112 and yoke 111 of the motor 10.

[0100] It should be noted that in this embodiment, the tenth wall surface 1123 and the eleventh wall surface 1124 are planar walls and are parallel to each other. In this case, Wt is the distance between two corresponding points at any positions on the tenth wall surface 1123 and the eleventh wall surface 1124. In other embodiments, the tenth wall surface 1123 and the eleventh wall surface 1124 are planar walls and have an angle therebetween (this angle may be due to design requirements or processing errors). In this case, Wt is the minimum distance between the tenth wall surface 1123 and the eleventh wall surface 1124. In specific operation, the two measuring ends of a vernier caliper can be respectively abutted against the tenth wall surface 1123 and the eleventh wall surface 1124, and the vernier caliper can be translated along the radial direction of the stator assembly 100. The minimum reading on the vernier caliper is the minimum distance Wt between the tenth wall surface 1123 and the eleventh wall surface 1124. In another embodiment, the tenth wall surface 1123 and the eleventh wall surface 1124 may also be other irregular shapes. The definition of Wt in this embodiment is the same as that in the above embodiment and is not repeated here.

[0101] Referring to Figures 1-2, 11-13, and 16, in some embodiments, the number of teeth 112 of the stator core 110 is X, where X ≥ 6. The number X of teeth 112 can be greater than the number of permanent magnets 230. The plurality of teeth 112 include a first tooth 112a and a second tooth 112b that are adjacently arranged along the circumferential direction m of the rotation axis 20. The first tooth 112a and the second tooth 112b are spaced apart, and the space (i.e., the tooth slot) between the first tooth 112a and the second tooth 112b is used to accommodate the coil winding. It should be noted that the first tooth 112a and the second tooth 112b are any two teeth 112 that are adjacent to each other along the circumferential direction m, and the difference in naming between the two is only for distinction. The first tooth portion 112a includes a third end portion 1121 facing away from the yoke portion 111 (the third end portion 1121 is the tooth shoe portion of the first tooth portion 112a), and the second tooth portion 112b includes a fourth end portion 1122 facing away from the yoke portion 111 (the fourth end portion 1122 is the tooth shoe portion of the second tooth portion 112b). Along the circumferential direction m, the third end portion 1121 and the fourth end portion 1122 are spaced apart, and the minimum spacing Wx between the third end portion 1121 and the fourth end portion 1122 satisfies:

[0102] Specifically, the above formula is equivalent to:

[0103] Among them, let:

[0104] Therefore:

[0105] The size of T3 is substantially equal to the maximum arrangement space along the sidewall of a single permanent magnet 230 facing away from the rotation axis 20 along the circumferential direction m. The minimum spacing Wx between the third end 1121 and the fourth end 1122 can be T3 / 10, 3T3 / 25, 7T3 / 50, 4T3 / 25, or T3 / 5, among others. The width between the tooth shoes of the stator core 110 significantly affects the iron loss of the tooth shoes and the sinusoidality of the air gap flux density, thus affecting the efficiency of the motor 10, as well as the cogging torque and torque ripple. Cogging torque is the torque generated by the interaction between the permanent magnet 230 and the core when the winding of the permanent magnet motor 10 is not energized. It is caused by fluctuations in the tangential component of the interaction force between the permanent magnet 230 and the armature teeth. When Wx ranges from T3 / 10 to T3 / 5, the distribution of the air gap flux density can be altered, reducing the cogging torque of the motor 10.

[0106] 1-2, 11-13, and 16, in some embodiments, the tooth portion 112 has a tenth wall surface 1123 on one side along the circumferential direction m of the rotation axis 20 and an eleventh wall surface 1124 on the other side along the circumferential direction m. The tenth wall surface 1123 defines a boundary line 1125 with the second inner circumferential wall of the yoke 111. The intersection of the tenth wall surface 1123 and the inner circumferential wall of the yoke 111 may have a rounded chamfer or a straight chamfer. When the intersection of the tenth wall surface 1123 and the inner circumferential wall of the yoke 111 has a chamfer, the boundary line 1125 is defined as the side edge of the chamfer away from the tenth wall surface 1123. In this embodiment, the maximum outer diameter of the outer peripheral wall of the yoke 111 is the maximum outer diameter of the stator core 110 (in other embodiments, the outer side of the yoke 111 may further be provided with external teeth, and the maximum outer diameter of the external teeth is the maximum outer diameter of the stator core 110). The minimum distance We between the boundary line 1125 and the outer peripheral wall of the yoke 111 satisfies:

[0107] Specifically, the above formula is equivalent to:

[0108] Among them, let:

[0109] Therefore:

[0110] T4 is substantially equal to the maximum radial width of the stator core 110, and the minimum distance We between the boundary line 1125 and the outer peripheral wall of the yoke 111 can be T4 / 6, 2T4 / 9, 5T4 / 18, or T4 / 3. When We is within the range of T4 / 6 to T4 / 3, the distribution of AC loss and iron loss in the stator winding of the motor 10 can be optimized, thereby improving the overall efficiency of the motor 10.

[0111] Referring to FIG. 16 , in a specific embodiment, when the D2 size is 74.8 mm (error ± 0.2 mm), the D3 size is 136-142 mm, the Wt size is 9.95 mm (error ± 0.2 mm), the We size is 7.3 mm (error ± 0.2 mm), the Wx size is 3-4.2 mm, and the K size is 4.4 mm (error ± 0.2 mm), the efficiency and cost ratio of the motor 10 is relatively good.

[0112] In another specific embodiment, when the inner diameter of the inner core is 12.7 mm (error ± 0.2 mm), the D3 size is 136-142 mm, the Wr size is 4.3 mm (error ± 0.2 mm), the Wa size is 2.3 mm (error ± 0.2 mm), the Wm size is 8 mm (error ± 0.2 mm), the radial length of the permanent magnet is 24 mm (error ± 0.2 mm), the L3 size is 4.4 mm (error ± 0.2 mm), the L5 size is 5.2 mm (error ± 0.2 mm), the radial size of the second limiting protrusion is 0.3 mm (error ± 0.2 mm), and the radial size of the first limiting protrusion is 0.92 mm (error ± 0.2 mm), the efficiency and cost ratio of the motor is the highest, and secondly, the motor's anti-demagnetization and shaft voltage reduction index requirements are met.

[0113] In Figures 11-13 , in some embodiments, the stator core 110 includes a second outer peripheral wall, which is provided with a second injection molding groove 1111. In some embodiments, the stator assembly 100 further includes a second injection molding portion that encapsulates the stator core 110 and the coil windings. Specifically, the second injection molding portion fills the second injection molding groove 1111, thereby securing the laminations of the stator core 110.

[0114] The third aspect of the present application further provides an air supply assembly, comprising the motor 10 of any of the above embodiments. The air supply assembly is used to drive air in a target direction and can be used in appliances such as electric fans, air conditioners, hair dryers, range hoods, and fresh air devices.

[0115] The fourth aspect of the present application further provides an air treatment device, which includes the above-mentioned air supply assembly. The air treatment device can specifically be an electric fan, air conditioner, hair dryer, range hood, fresh air device or other electrical appliances.

[0116] 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.

[0117] 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.

[0118] 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 using the contents of the present application description and drawings under the inventive concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A rotor assembly configured to rotate about a rotation axis and comprising: A rotor core, comprising an inner core and an outer core disconnected from the inner core, wherein the outer core comprises a plurality of core units disconnected from each other, each of the core units being distributed around the inner core along the circumference of the rotation axis, and each of the core units comprising a plurality of core laminations stacked along a first direction, wherein the first direction is parallel to the rotation axis; Along the first direction, the thickness of the iron core lamination with the smallest thickness is Ts; a mounting groove is provided between each two adjacent iron core units; and, N permanent magnets, N≥4, each of the permanent magnets is arranged in each of the mounting slots in a one-to-one correspondence, two of the permanent magnets are a first permanent magnet and a second permanent magnet, the first permanent magnet and the second permanent magnet are distributed on opposite sides of the rotation axis along a second direction, the second direction is perpendicular to the rotation axis, the first permanent magnet includes a first wall surface facing the second permanent magnet, and the second permanent magnet includes a second wall surface facing the first permanent magnet; as well as The maximum distance D1 between the first wall surface and the second wall surface and the maximum distance Wm between the two sides of the first wall surface along the circumferential direction satisfy: Among them: 1≤K≤5.

2. The rotor assembly as described in claim 1, wherein the inner core is in a ring shape arranged around the rotation axis, the inner core includes a first inner circumferential wall close to the rotation axis and a first outer circumferential wall away from the rotation axis, and along the second direction, the maximum distance Wr between the first inner circumferential wall and the first outer circumferential wall satisfies: Wr≥2×Ts; or Wr≥2.5mm. 3 . The rotor assembly according to claim 1 , wherein along the radial direction of the rotor assembly, a minimum distance Wa between each of the core units and the inner core satisfies: Wa ≥ 2×Ts; or Wa ≥ 2.5 mm.

4. The rotor assembly according to any one of claims 1 to 3, wherein: The core unit has a third wall surface located at one side along the circumferential direction, the third wall surface is provided with a limiting protrusion, and the limiting protrusion is suitable for abutting against a side wall of the permanent magnet facing away from or facing the rotation axis; and The maximum distance L1 from the end of the limiting protrusion away from the third wall to the third wall satisfies: L1≥Ts; or the minimum distance L2 between the side wall of the limiting protrusion facing the rotation axis and the side wall away from the rotation axis satisfies: L2≥Ts.

5. The rotor assembly according to any one of claims 1 to 4, wherein: Two of the core units are a first core unit and a second core unit, and the mounting groove is defined between the first core unit and the second core unit; and The first core unit includes a first end away from the rotation axis, the second core unit includes a second end away from the rotation axis, and a minimum distance L3 between the first end and the second end satisfies: L3≤0.6×Wm; or 0.4×Wm≤L3≤0.6×Wm.

6. The rotor assembly according to any one of claims 1 to 5, wherein: Two of the core units are a first core unit and a second core unit, and the mounting groove is defined between the first core unit and the second core unit; The first core unit has a fourth wall surface facing the second core unit, the fourth wall surface is provided with a first limiting protrusion and a second limiting protrusion, the second core unit has a fifth wall surface facing the first core unit, the fifth wall surface is provided with a third limiting protrusion and a fourth limiting protrusion; The first limiting protrusion and the third limiting protrusion are suitable for abutting against the wall surface of the permanent magnet away from the rotation axis, and the second limiting protrusion and the fourth limiting protrusion are suitable for abutting against the wall surface of the permanent magnet facing the rotation axis; and The minimum distance between the first limiting protrusion and the third limiting protrusion is L4, and the minimum distance between the second limiting protrusion and the fourth limiting protrusion is L5, wherein: L5≥L4.

7. A rotor assembly as described in claim 6, wherein the first limiting protrusion is located at the end of the fourth wall away from the rotation axis, the second limiting protrusion is located at the end of the fourth wall close to the rotation axis, the third limiting protrusion is located at the end of the fifth wall away from the rotation axis, and the fourth limiting protrusion is located at the end of the fifth wall close to the rotation axis. 8 . The rotor assembly according to claim 1 , wherein the permanent magnet extends out of one or both ends of the mounting slot along the first direction.

9. The rotor assembly according to any one of claims 1 to 8, wherein the core unit has a third wall surface that fits the permanent magnet, the third wall surface is provided with a first injection groove, and the first injection groove penetrates the core unit along the first direction. 10 . The rotor assembly according to claim 1 , further comprising a first injection-molded portion, wherein the first injection-molded portion connects the outer iron core and the inner iron core, and the injection-molded portion fills a gap between the outer iron core and the inner iron core.

11. A motor, comprising: The rotor assembly according to any one of claims 1 to 10; as well as The stator assembly is arranged around the rotor assembly. 12 . The motor of claim 11 , wherein the stator assembly comprises a stator core and a coil winding connected to the stator core, the stator core comprises a second outer peripheral wall, and the second outer peripheral wall is provided with a second injection molding groove. 13 . The motor of claim 12 , wherein the stator assembly further comprises a second injection-molded portion, the second injection-molded portion wrapping the stator core and the coil winding.

14. An air supply assembly, comprising the motor according to claim 13.

15. An air treatment device, comprising the air supply assembly according to claim 14.

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