CN117639324A

CN117639324A - Rotor assembly, motor, air supply assembly and air treatment device

Info

Publication number: CN117639324A
Application number: CN202311670627.3A
Authority: CN
Inventors: 贾武豪; 毛临书; 徐飞; 程云峰
Original assignee: Guangdong Meizhi Compressor Co Ltd; Guangdong Meizhi Precision Manufacturing Co Ltd; Guangdong Welling Motor Manufacturing Co Ltd
Current assignee: Guangdong Meizhi Compressor Co Ltd; Guangdong Meizhi Precision Manufacturing Co Ltd; Guangdong Welling Motor Manufacturing Co Ltd
Priority date: 2023-12-06
Filing date: 2023-12-06
Publication date: 2024-03-01

Abstract

The invention discloses a rotor assembly, a motor, an air supply assembly and an air treatment device. Each core unit includes a plurality of core laminations arranged in a stacked configuration along a first direction, the first direction being parallel to the axis of rotation. In the first direction, the thickness dimension of the core sheet having the smallest thickness is Ts. Two of the plurality of permanent magnets are a first permanent magnet including a first wall facing the second permanent magnet and a second permanent magnet including a second wall facing the first permanent magnet. Wherein the first wall surface and the second wall surface are the mostLarge distance D ₁ The maximum distance Wm between two sides of the first wall surface along the circumferential direction meets certain size requirements. In the scheme, the magnetic leakage of the permanent magnet at the supporting position of the outer iron core, which is close to the rotating axis, is effectively limited, and the power density of the motor is improved.

Description

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

Technical Field

The invention relates to the technical field of electric driving devices, in particular to a rotor assembly, a motor, an air supply assembly and an air treatment device.

Background

In the split type rotor assembly, a rotor core of the rotor assembly comprises an inner core and an outer core which are disconnected with each other, the outer core comprises a plurality of core units which are arranged around the inner core, each core unit is disconnected with each other along the axis of the rotation axis of the rotor assembly, and a permanent magnet is arranged between every two core units. In the related art, magnetic leakage is easily generated at the end position of each iron core unit close to the rotation axis, so that the power density of the motor is reduced.

Disclosure of Invention

The invention mainly aims to provide a rotor assembly, a motor, an air supply assembly and an air treatment device, which can reduce magnetic leakage of the rotor assembly and improve power density of the motor.

To achieve the above object, the present invention proposes a rotor assembly configured to rotate about a rotation axis, the rotor assembly comprising:

a rotor core including an inner core and an outer core disconnected from the inner core, the outer core including a plurality of core units disconnected from each other, each of the core units being distributed around the inner core in a circumferential direction of the rotation axis, each of the core units including a plurality of core laminations arranged in a stacked manner in a first direction, the first direction being parallel to the rotation axis; the thickness dimension of the core lamination sheet with the minimum thickness is Ts along the first direction; a mounting groove is formed between every two adjacent iron core units; the method comprises the steps of,

N permanent magnets, N is more than or equal to 4, each permanent magnet is arranged in each mounting groove in a one-to-one correspondence manner, 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 two opposite sides of the rotation axis along a second direction, the second direction is perpendicular to the rotation axis, the first permanent magnet comprises a first wall surface facing the second permanent magnet, and the second permanent magnet comprises a second wall surface facing the first permanent magnet;

wherein the maximum distance D between the first wall surface and the second wall surface ₁ The maximum spacing Wm between the two sides of the first wall surface along the circumferential direction satisfies:

the method comprises the steps of carrying out a first treatment on the surface of the Wherein: k is more than or equal to 1 and less than or equal to 5.

In some embodiments, the inner core is annular arranged around the rotation axis, the inner core includes a first inner peripheral wall near the rotation axis and a first outer peripheral wall facing away from the rotation axis, and along the second direction, a maximum distance Wr between the first inner peripheral wall and the first outer peripheral wall satisfies: wr is more than or equal to 2 xTs; or Wr is more than or equal to 2.5mm.

In some embodiments, a minimum distance Wa of each of the core units from the inner core in a radial direction of the rotor assembly satisfies: wa is more than or equal to 2 xTs; or Wa.gtoreq.2.5 mm.

In some embodiments, the iron core unit has a third wall surface located at one side along the circumferential direction, the third wall surface is provided with a limit protrusion, and the limit protrusion is suitable for abutting against a side wall of the permanent magnet facing away from or towards the rotation axis;

the limit protrusion is away from the maximum distance L from the end of the third wall surface to the third wall surface ₁ The method meets the following conditions: l (L) ₁ Not less than Ts; alternatively, the limit projection faces the side wall of the rotation axis to the most between the side walls facing away from the rotation axisSmall distance L ₂ The method meets the following conditions: l (L) ₂ ≥Ts。

In some embodiments, two of the core units are a first core unit and a second core unit, the first core unit and the second core unit defining the mounting slot therebetween;

the first core unit comprises a first end part facing away from the rotation axis, the second core unit comprises a second end part facing away from the rotation axis, and the minimum distance L between the first end part and the second end part ₃ The method meets the following conditions:

L ₃ less than or equal to 0.6 XWm; or 0.4 XWm.ltoreq.L ₃ ≤0.6×Wm。

The first iron core unit is provided with a fourth wall surface facing the second iron core unit, the fourth wall surface is provided with a first limiting protrusion and a second limiting protrusion, the second iron core unit is provided with a fifth wall surface facing the first iron core unit, and 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 being abutted against the wall surface of the permanent magnet, which faces away from the rotation axis, and the second limiting protrusion and the fourth limiting protrusion are suitable for being abutted against the wall surface of the permanent magnet, which faces towards the rotation axis;

the minimum distance between the first limit protrusion and the third limit protrusion is L ₄ The minimum distance between the second limit protrusion and the fourth limit protrusion is L ₅ The method comprises the steps of carrying out a first treatment on the surface of the Wherein L is ₅ ≥L ₄ 。

In some embodiments, the first limit protrusion is located at an end of the fourth wall facing away from the rotation axis, the second limit protrusion is located at an end of the fourth wall facing toward the rotation axis, the third limit protrusion is located at an end of the fifth wall facing away from the rotation axis, and the fourth limit protrusion is located at an end of the fifth wall facing toward the rotation axis.

In some embodiments, the permanent magnet protrudes from one or both ends of the mounting groove in the first direction.

In some embodiments, the iron core unit has a third wall surface attached to the permanent magnet, and the third wall surface is provided with a first injection molding groove, and the first injection molding groove penetrates through the iron core unit along the first direction.

In some embodiments, the rotor assembly further comprises a first injection molded portion connecting the outer core and the inner core, and the injection molded portion fills a gap between the outer core and the inner core.

Embodiments of the second aspect of the present invention also provide an electric machine comprising:

a rotor assembly as claimed in any one of the preceding claims; and

a stator assembly disposed about the rotor assembly.

In some embodiments, the stator assembly includes a stator core including a second peripheral wall provided with a second injection molded slot, and a coil winding connected to the stator core.

In some embodiments, the stator assembly further comprises a second injection molded portion that encases the stator core and the coil windings.

An embodiment of the third aspect of the present invention further provides an air supply assembly, including the motor described above.

An embodiment of the fourth aspect of the present invention further provides an air treatment device, including the air supply assembly described above.

Compared with the prior art, the invention has the beneficial effects that:

in the technical scheme of the invention, the rotor assembly comprises a rotor core and a permanent magnet, wherein the rotor core comprises an inner core and an outer core, and the outer core comprises a plurality of core units arranged around the inner core. Each core unit includes a plurality of core laminations arranged in a stacked manner along a first direction, the first directionParallel to the axis of rotation. In the first direction, the thickness dimension of the core sheet having the smallest thickness is Ts. Two of the plurality of permanent magnets are a first permanent magnet including a first wall facing the second permanent magnet and a second permanent magnet including a second wall facing the first permanent magnet. Wherein the maximum distance D between the first wall surface and the second wall surface ₁ The maximum distance Wm between two sides of the first wall surface along the circumferential direction is as follows:

the method comprises the steps of carrying out a first treatment on the surface of the Wherein K is more than or equal to 1 and less than or equal to 5. In this scheme, limited the permanent magnet effectively and be close to the magnetic leakage of the both ends supporting position of axis of rotation at outer iron core, improved motor power density, reduce motor cost. The width of one end of the permanent magnet, which is close to the rotation axis, is restrained, so that the low-speed light-load performance of the motor and the anti-demagnetization strength of the permanent magnet are improved, and the motor can operate efficiently and reliably.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic side view of a rotor assembly in which a core unit and a permanent magnet are combined according to an embodiment of the present invention; wherein the viewing angle is parallel to the first direction;

FIG. 2 is a schematic side view of a permanent magnet assembly according to an embodiment of the present invention; wherein the viewing angle is parallel to the first direction;

FIG. 3 is a schematic side view of a core unit according to an embodiment of the present invention; wherein the viewing angle is parallel to the first direction;

FIG. 4 is an enlarged partial schematic view of FIG. 3 at A1;

FIG. 5 is an enlarged partial schematic view at A2 in FIG. 3;

FIG. 6 is a schematic side view of a core pack according to an embodiment of the invention; wherein the viewing angle is parallel to the first direction;

FIG. 7 is an enlarged partial schematic view at A3 in FIG. 6;

FIG. 8 is a schematic perspective view of a core pack according to an embodiment of the present invention;

FIG. 9 is a schematic side view of an inner core according to an embodiment of the present invention; wherein the viewing angle is parallel to the first direction;

FIG. 10 is a schematic perspective view of a rotor assembly according to an embodiment of the present invention;

FIG. 11 is a schematic side view of a rotor core, stator core and permanent magnet combination of an electric machine according to an embodiment of the present invention; wherein the viewing angle is parallel to the first direction;

FIG. 12 is a schematic side view of a stator core according to an embodiment of the present invention; wherein the viewing angle is parallel to the first direction;

FIG. 13 is an enlarged partial schematic view of FIG. 12 at A4;

FIG. 14 is a diagram showing L in an embodiment of the present invention ₃ Histogram of/Wm versus no-load back-emf per unit value, and L ₃ A line graph of the relationship between Wm and demagnetizing rate;

FIG. 15 is a plot of Wm versus demagnetizing current for one embodiment of the present invention;

FIG. 16 is a diagram of D in an embodiment of the invention ₂ /D ₃ Graph with motor efficiency; the high-speed heavy-load efficiency curve, the low-speed light-load efficiency curve and the comprehensive average efficiency curve of the motor are shown.

Reference numerals illustrate:

a motor 10;

a stator assembly 100;

a stator core 110; a yoke 111; a second injection groove 1111; a stopper 1112; a tooth 112; a third end 1121; a fourth end 1122; a tenth wall 1123; an eleventh wall 1124; an intersection line 1125;

A first tooth portion 112a; a second tooth portion 112b;

a rotor assembly 200;

a rotor core 210; an inner core 211; a first inner peripheral wall 2111; a first peripheral wall 2112; an outer core 212; a core unit 2121; a first end 21211; a second end 21212; first limit projection 21213; a third limit projection 21214; a second limit projection 21215; fourth limit projection 21216;

a first injection groove 21217; iron core laminations 213; a mounting groove 214; a third wall surface 215; a fourth wall 216;

a fifth wall 217; a limit projection 218; a first core unit 2121a; a second core unit 2121b;

a first injection part 220;

a permanent magnet 230; an eighth wall 231; a ninth wall 232; a first wall 233; a second wall 234;

a sixth wall 235; a seventh wall 236; a first permanent magnet 230a; a second permanent magnet 230b;

an axis of rotation 20;

a first direction y;

a second direction x;

and a circumferential direction m.

The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In view of this, and referring to fig. 1-16, in some embodiments of the present invention, a rotor assembly 200 is provided, the rotor assembly 200 being configured to rotate about a rotational axis 20. Rotor assembly 200 rotor core 210 and N permanent magnets 230, N.gtoreq.4, specifically, N may be 4, 6, 8, 10 or 12, etc., in this embodiment, referring to FIGS. 1-5, the number of permanent magnets 230 is specifically 10.

Referring to fig. 1 to 3, 6 and 8, the rotor core 210 includes an inner core 211 and an outer core 212 disconnected from the inner core 211, and it should be noted that "the inner core 211 is disconnected from the outer core 212" merely indicates that the two cores are not in direct contact, and does not indicate that the two cores have any connection relationship, and in this embodiment, the outer core 212 and the inner core 211 are indirectly connected through the first injection molding portion 220. The outer core 212 includes a plurality of core units 2121 that are disconnected from each other, and each core unit 2121 is not directly contacted, in this embodiment, each core unit 2121 is indirectly contacted by the permanent magnet 230 and/or the first injection-molded portion 220. Each core unit 2121 is distributed around the inner core 211 along the circumferential direction m of the rotational axis 20, specifically, each core unit 2121 is distributed in a circular array with the rotational axis 20 as a central axis, and the distances between every two adjacent core units 2121 along the circumferential direction m are equal. Each core unit 2121 includes a plurality of core laminations 213 arranged in a stack in a first direction y, which is parallel to the axis of rotation 20. In first direction y, the thickness dimension of smallest thickness lamination stack 213 is Ts. That is, when the thickness of each lamination stack 213 in the first direction y is equal, ts is the thickness of each lamination stack 213 in the first direction y. When the thicknesses of at least two lamination sheets 213 in the first direction y are not equal, each lamination sheet 213 has one thickness in the first direction y, respectively, and Ts is the thickness dimension of the lamination sheet 213 in which the thickness dimension is the smallest.

Mounting grooves 214 are formed between every two adjacent iron core units 2121, and each permanent magnet 230 is arranged in each mounting groove 214 in a one-to-one correspondence. It should be noted that, in the present embodiment, the permanent magnet 230 disposed in the single mounting slot 214 is defined as one permanent magnet 230, and in some embodiments, one permanent magnet230 may be a single individual. In other embodiments, one permanent magnet 230 may include a plurality of permanent magnet units, each of which 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 two opposite sides of the rotation axis 20 along a 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 the "second permanent magnet 230b" referred to herein are any two permanent magnets 230 located on two opposite sides of the rotor assembly 200 in the radial direction, and thus, in the embodiment shown in fig. 2, there are five pairs of permanent magnets 230, and two permanent magnets 230 in each pair of permanent magnets 230 may be referred to as "first permanent magnet 230a" and "second permanent magnet 230b". In other embodiments, such as when rotor assembly 200 includes twelve permanent magnets 230, it has six pairs of "first permanent magnets 230a" and "second permanent magnets 230b". For convenience of description, the "first permanent magnet 230a" and the "second permanent magnet 230b" in one pair are exemplified below. The first permanent magnet 230a includes a first wall surface 233 facing the second permanent magnet 230b, and the second permanent magnet 230b includes a second wall surface 234 facing the first permanent magnet 230 a. Wherein, the maximum distance D between the first wall surface 233 and the second wall surface 234 ₁ The maximum spacing Wm of both sides of the first wall surface 233 in the circumferential direction m satisfies:

the method comprises the steps of carrying out a first treatment on the surface of the The above formula is equivalent to:

the method comprises the steps of carrying out a first treatment on the surface of the Wherein, let:

the method comprises the steps of carrying out a first treatment on the surface of the Therefore:

Wm＝K ₁ -K×Ts

the method comprises the steps of carrying out a first treatment on the surface of the Wherein: k is more than or equal to 1 and less than or equal to 5. Illustratively, K may be 1, 2, 3, 4, 5, or the like. T (T) ₁ Substantially equal to the theoretical upper limit of the dimension of the first wall 233. 1.ltoreq.K.ltoreq.5, i.e., the maximum spacing Wm of the two sides of first wall surface 233 in circumferential direction m is smaller than the theoretical maximum dimension minus one to five times the minimum wall thickness of core stack 213. In this scheme, the magnetic leakage of the permanent magnet 230 at the two end supporting positions of the outer iron core 212, which are close to the rotation axis 20, is effectively limited, the power density of the motor 10 is improved, and the cost of the motor 10 is reduced. By restricting the width of the end of the permanent magnet 230 near the rotation axis 20, the low-speed light-load performance of the motor 10 and the anti-demagnetization strength of the permanent magnet 230 are improved, and the motor 10 can operate efficiently and reliably.

It should be noted that, since the first permanent magnet 230a may be any one of the permanent magnets 230, in some embodiments, the maximum distance between two sides of the wall surface of all the permanent magnets 230 facing the rotation axis 20 along the circumferential direction m may be Wm. Also, the first permanent magnet 230a includes a sixth wall surface 235 and a seventh wall surface 236 that are opposed in the circumferential direction m, and when the sixth wall surface 235 and the seventh wall surface 236 are planar walls and are arranged in parallel with each other, the size of the interval between the sixth wall surface 235 and the seventh wall surface 236 is equal to the maximum interval Wm of both sides of the first wall surface 233 in the circumferential direction m. When the sixth wall surface 235 and the seventh wall surface 236 are not parallel or both are not planar walls, the maximum pitch dimension from the end of the sixth wall surface 235 near the rotation axis 20 to the end of the seventh wall surface 236 near the rotation axis 20 is equal to the maximum pitch Wm of both sides of the first wall surface 233 in the circumferential direction m. When chamfers are provided between the first wall 233 and the sixth wall 235 and the seventh wall 236, respectively, a maximum distance between a side near the sixth wall 235 at the chamfer between the first wall 233 and the sixth wall 235 and a side near the seventh wall 236 at the chamfer between the first wall 233 and the seventh wall 236 is defined as Wm.

Referring to fig. 2-5, and 9, in some embodiments, the inner core 211 is annular disposed about the rotational axis 20, the inner core 211 including a first inner peripheral wall 2111 proximate the rotational axis 20 and a first outer peripheral wall 2112 facing away from the rotational axis 20, the maximum distance Wr of the first inner peripheral wall 2111 of the inner core 211 from the first outer peripheral wall 2112 of the inner core 211 along the first direction y being: wr is more than or equal to 2 XTs. Illustratively, wr may be 2Ts, 2.2Ts, 2.4Ts, 2.6Ts, 2.8Ts or 3Ts, etc. In this scheme, wr is equal to the maximum annular width of the inner core 211 in the second direction x. When the Wr size is large, the gap between the inner core 211 and the outer core 212 may be reduced, thereby inconvenient injection molding, and reducing the connection stability between the inner core 211 and the outer core 212. When Wr is small, the inner core 211 has poor supporting effect on the rotating shaft penetrating therein. In the embodiment, when Wr is equal to or greater than 2×ts, on one hand, the gap between the inner core 211 and the outer core 212 can be increased, so as to increase the injection space and improve the connection stability between the inner core 211 and the outer core 212; on the other hand can also promote the support steadiness to the pivot.

Referring to fig. 2-5, and 9, in some embodiments, the inner core 211 is annular disposed about the rotational axis 20, the inner core 211 including a first inner peripheral wall 2111 proximate the rotational axis 20 and a first outer peripheral wall 2112 facing away from the rotational axis 20, the maximum distance Wr of the first inner peripheral wall 2111 from the first outer peripheral wall 2112 along the first direction y being: wr is more than or equal to 2.5mm. Illustratively, wr may be 2.5mm, 2.7mm, 3mm, 3.2mm, 3.5mm, 3.7mm, or the like. In the scheme, on one hand, the gap between the inner iron core 211 and the outer iron core 212 can be increased, so that the injection space is increased, and the connection stability between the inner iron core 211 and the outer iron core 212 is improved; on the other hand can also promote the support steadiness to the pivot. In a further embodiment, wr may also satisfy Wr+.2XTs simultaneously.

Referring to fig. 2-5, and 9, in some embodiments, along the radial direction of the rotor assembly 200, the minimum distance Wa of each core unit 2121 from the inner core 211 satisfies: wa is not less than 2 XTs. Illustratively, wa may be 2Ts, 2.2Ts, 2.4Ts, 2.6Ts, 2.8Ts, or 3Ts, etc. In the scheme, on one hand, the gap between the inner iron core 211 and the outer iron core 212 can be increased, so that the injection space is increased, and the connection stability between the inner iron core 211 and the outer iron core 212 is improved; on the other hand can also promote the support steadiness to the pivot.

Referring to fig. 2-5, and 9, in some embodiments, along the radial direction of the rotor assembly 200, the minimum distance Wa of each core unit 2121 from the inner core 211 satisfies: wa is more than or equal to 2.5mm. Illustratively, wa may be 2.5mm, 2.7mm, 3mm, 3.2mm, 3.5mm, 3.7mm, or the like. In the scheme, on one hand, the gap between the inner iron core 211 and the outer iron core 212 can be increased, so that the injection space is increased, and the connection stability between the inner iron core 211 and the outer iron core 212 is improved; on the other hand can also promote the support steadiness to the pivot. In a further embodiment, wa may also satisfy Wa+.2XTs simultaneously.

Referring to fig. 3-7, in some embodiments, to form stable positioning for the permanent magnet 230, the core unit 2121 has a third wall surface 215 located at one side in the circumferential direction m, and the third wall surface 215 is provided with a stopper protrusion 218. The limiting protrusion 218 is adapted to abut against a side wall of the permanent magnet 230 facing away from or towards the rotation axis 20, specifically, in an embodiment, the limiting protrusion 218 may be disposed on a side of the third wall surface 215 facing away from the rotation axis 20 (in this case, the limiting protrusion 218 is hereinafter referred to as a first limiting protrusion 21213 or a third limiting protrusion 21214), so as to abut against a side of the permanent magnet 230 facing away from the rotation axis 20, so as to limit the position of the permanent magnet 230 in a direction away from the rotation axis 20. In another embodiment, the limiting protrusion 218 may be disposed on a side of the third wall 215 near the rotation axis 20 and abuts against a wall surface of the permanent magnet 230 facing the rotation axis 20 (the limiting protrusion 218 is hereinafter referred to as a second limiting protrusion 21215 or a fourth limiting protrusion 21216) to limit displacement of the permanent magnet 230 toward the direction near the rotation axis 20. In yet another embodiment, a side of the third wall surface 215 near the rotation axis 20 and a side facing away from the rotation axis 20 may be provided with limiting protrusions 218, respectively, where the two limiting protrusions 218 correspondingly abut against wall surfaces of the permanent magnets 230 on two sides in the radial direction of the rotor assembly 200.

Excessive extension of the stop tab 218 beyond the third wall 215 increases the magnetic leakage of the rotor assembly 200. When the length of the limiting protrusion 218 extending out of the third wall surface 215 is too short, the limiting effect of the limiting protrusion 218 on the permanent magnet 230 is poor. In view of this, and referring to fig. 7, in some embodiments, the limit projection 218 faces away from the end of the third wall 215 to a maximum distance L of the third wall 215 ₁ The method meets the following conditions: l (L) ₁ And (5) not less than Ts. Illustratively, L ₁ Can be Ts, 1.2Ts, 1.3Ts, 1.4Ts, 1.5Ts or 1.6Ts, etc. In this solution, the limiting protrusion 218 can well limit the permanent magnet 230, and make the magnetic leakage of the rotor assembly 200 smaller.

Too long a radial length of stop tab 218 increases the magnetic leakage of rotor assembly 200. The length of the stopper projection 218 in the radial direction is too short, and the strength and rigidity of the stopper projection 218 are poor. In view of this, and referring to fig. 7, in some embodiments, the spacing projection 218 faces the sidewall of the rotational axis 20 to a minimum spacing L between the sidewalls facing away from the rotational axis 20 ₂ The method meets the following conditions: l (L) ₂ And (5) not less than Ts. Illustratively, L ₂ Can be Ts, 1.2Ts, 1.3Ts, 1.4Ts, 1.5Ts or 1.6Ts, etc. In this arrangement, the stop tab 218 provides both a high strength and rigidity and also provides less magnetic leakage from the rotor assembly 200.

Referring to fig. 2-5, in some embodiments, two of the core units 2121 are a first core unit 2121a and a second core unit 2121b, and a mounting groove 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 from each other along the circumferential direction m. Note that the difference in the designations of the "first core unit 2121a" and the "second core unit 2121b" is merely for distinction, and any two core units 2121 adjacent to each other in the circumferential direction m among the core units 2121 may be referred to as a first core unit 2121a and a second core unit 2121b. The first core unit 2121a includes a first end 21211 facing away from the rotational axis 20, and the second core unit 2121b includes a second end 21212 facing away from the rotational axis 20, a minimum distance L between the first end 21211 and the second end 21212 ₃ The method meets the following conditions: l (L) ₃ Less than or equal to 0.6 XWm. Illustratively, L ₃ May be 0.2Wm, 0.3Wm, 0.4Wm, 0.5Wm or 0.6Wm, etc. Referring specifically to FIG. 14, when L ₃ when/Wm is gradually increased from 0 to 1, the demagnetizing rate of the motor 10 at the same demagnetizing current gradually increases, so that the efficiency of the motor 10 decreases. Thus L is ₃ Wm should not be too large, and is demonstrated when L ₃ At 0.6XWm or less, the demagnetizing rate of the motor 10 can be reduced, therebyThe efficiency of the motor 10 is improved.

In a further embodiment, a minimum distance L between the first end 21211 and the second end 21212 ₃ The method meets the following conditions: l is more than or equal to 0.4 XWm ₃ Less than or equal to 0.6 XWm. Illustratively, L ₃ May be 0.4Wm, 0.45Wm, 0.5Wm, 0.55Wm or 0.6Wm, etc. Referring specifically to FIG. 14, where L ₃ when/Wm is 0, the no-load counter potential per unit value is 1, when L ₃ when/Wm is gradually increased from 0 to 1, the no-load counter potential per unit gradually increases, but the demagnetizing rate of the motor 10 gradually increases at the same demagnetizing current. Thus, L ₃ Wm is neither too large nor too small, L ₃ Too large/Wm results in a large demagnetizing rate L of the motor 10 ₃ Too small a/Wm results in too large a magnetic leakage of the motor 10 and reduced efficiency of the motor 10. Demonstrated that when 0.4 XWm is less than or equal to L ₃ When the demagnetizing rate of the motor 10 is lower and the no-load counter potential per unit value is higher than or equal to 0.6 XWm, the motor 10 efficiency is higher.

Referring to fig. 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 2121 b. The first core unit 2121a has a fourth wall surface 216 facing the second core unit 2121b, and the fourth wall surface 216 is provided with at least two stopper protrusions 218, and for convenience of distinction, the two stopper protrusions 218 are named as a first stopper protrusion 21213 and a second stopper protrusion 21215, respectively. The second core unit 2121b has a fifth wall 217 facing the first core unit 2121a, and the fifth wall 217 is provided with at least two stopper protrusions 218, and for convenience of distinction, the two stopper protrusions 218 are named as a third stopper protrusion 21214 and a fourth stopper protrusion 21216, respectively. The first limit protrusion 21213 and the third limit protrusion 21214 are adapted to abut against a wall surface of the permanent magnet 230 facing away from the rotation axis 20, and the second limit protrusion 21215 and the fourth limit protrusion 21216 are adapted to abut against a wall surface of the permanent magnet 230 facing toward the rotation axis 20, i.e. the first limit protrusion 21213, the second limit protrusion 21215, the third limit protrusion 21214 and the fourth limit protrusion 21216 together limit the permanent magnet 230. Specifically, the minimum spacing between the first limit projection 21213 and the third limit projection 21214 is L ₄ The minimum spacing between the second spacing projection 21215 and the fourth spacing projection 21216 is L ₅ Wherein L is ₅ ≥L ₄ . In this aspect, the magnetic leakage of the outer core 212 at one end near the rotation axis 20 can be reduced, thereby improving the efficiency of the motor 10, and simultaneously, the limiting effect on the permanent magnet 230 can be improved, so that the rotor assembly 200 is prevented from moving in a direction away from the rotation axis 20 relative to the rotor core 210 due to the centrifugal force during rotation.

Referring to fig. 2-5, in some embodiments, the first stop tab 21213 is located at an end of the fourth wall 216 facing away from the rotational axis 20, the second stop tab 21215 is located at an end of the fourth wall 216 proximate to the rotational axis 20, the third stop tab 21214 is located at an end of the fifth wall 217 facing away from the rotational axis 20, and the fourth stop tab 21216 is located at an end of the fifth wall 217 proximate to the rotational axis 20. In this embodiment, the minimum distance L between the first limit bump 21213 and the third limit bump 21214 ₄ I.e., the minimum distance L between the first end 21211 and the second end 21212 ₃ . So that when L ₃ When too small, magnetic leakage is less than in a structure in which the stopper projection 218 is not provided.

In some embodiments, the permanent magnet 230 protrudes in the first direction y from one or both ends of the mounting slot 214. The embodiment can improve the utilization rate of the magnetic conductive material.

Referring to fig. 2-6, in some embodiments, the core unit 2121 has a third wall surface 215 that is attached to the permanent magnet 230, and the third wall surface 215 is provided with a first injection-molded groove 21217, and the first injection-molded groove 21217 penetrates the core unit 2121 in a first direction y. In some embodiments, the rotor assembly 200 further includes a first injection molded part 220, the first injection molded part 220 connecting the outer core 212 and the inner core 211, and the injection molded part filling a gap between the outer core 212 and the inner core 211. First injection molding 220 may also fill first injection molding groove 21217, thereby making the connection of each lamination stack 213 more secure.

Referring to fig. 2-6, in some embodiments, lamination 213 is provided with a stop 1112, where stop 1112 forms a recess in one side wall of lamination 213 along first direction y and a protrusion in the other side wall of lamination 213 along first direction y, where first direction y is parallel to rotational axis 20. In this solution, after a plurality of iron core laminations 213 are stacked and arranged along a direction parallel to the rotation axis 20, the protrusions of the other iron core laminations 213 on one side of the current iron core lamination 213 extend into the recesses of the current iron core lamination 213, and the protrusions on the other side of the current iron core lamination 213 extend into the recesses of the other iron core laminations 213, so that the relative positions of the iron core laminations 213 along the circumferential direction m are more stable, and the relative movement of the iron core laminations 213 along the circumferential direction m is not easy to generate. In other embodiments, each lamination of the stator core 110 may also be provided with a limiting portion 1112, which is not described herein.

The stator winding ac losses of the motor under heavy and light loads are different from the core losses, which makes the motor efficiency under heavy and light loads different. In the related art, the motor is low in efficiency when the motor is either focused on heavy load (the actual working load is more than 80% of the rated load) and therefore light load (the actual working load is less than 30% of the rated load); or pays attention to light load efficiency and thus lower efficiency when heavy load. When the motor has a heavy load working condition and a light load working condition, no matter whether the motor is designed to pay more attention to the heavy load working condition or the light load working condition, the overall comprehensive efficiency is not ideal when the motor works under various working conditions, namely when the motor is designed to pay more attention to the heavy load working condition, the overall comprehensive efficiency of the motor is not good because the efficiency of the actual operation under the light load working condition is lower; when the motor is designed to pay more attention to the light-load working condition, the efficiency of the actual working under the heavy-load working condition is lower, so that the overall comprehensive efficiency of the motor is poor.

To sum up, in order to make the overall comprehensive power of the motor better under heavy load working conditions and light load working conditions, the stator winding alternating current loss and the iron loss of the motor under different working conditions need to be balanced. In the related art, however, a specific means for achieving the balance between the two is not clear. Through demonstration analysis, the applicant finds that the ratio of the magnet outer diameter of the motor to the outer diameter of the stator core has a correlation with the overall integrated power of the motor. The method and the device have the advantages that firstly, the thought of balancing the alternating current loss and the iron loss of the motor stator winding is provided, and a specific means for balancing the alternating current loss and the iron loss of the motor stator winding is provided through experimental demonstration under the guidance of the thought, so that the technical effect of better overall efficiency of the motor when the motor works under different working conditions is achieved.

In view of this, embodiments of the second aspect of the present invention also provide an electrical machine 10, the electrical machine 10 comprising a rotor assembly 200 of any of the above and a stator assembly 100, the stator assembly 100 being arranged around the rotor assembly 200.

Referring to fig. 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 a minimum distance D between the eighth wall 231 and the ninth wall 232 ₂ . In particular, the eighth wall 231 and the ninth wall 232 may be planar walls and parallel, wherein the minimum distance between the eighth wall 231 and the ninth wall 232 is D ₂ Namely, the distance from any point of the eighth wall surface 231 to the ninth wall surface 232 or the distance from any point of the ninth wall surface 232 to the eighth wall surface 231. In other embodiments, the eighth wall 231 and the ninth wall 232 are planar walls and may have a small included angle therebetween (the included angle may be formed by design requirements, machining errors or assembly errors); or eighth wall 231 and ninth wall 232 may be cambered surfaces, in which case D ₂ Is the minimum distance between the eighth wall 231 and the ninth wall 232 in the radial direction of the rotor assembly 200.

The stator assembly 100 is disposed 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 arranged around the outside of the rotor assembly 200, and each tooth 112 is provided between the yoke 111 and the rotor core 210 and connects the yoke 111. Each tooth 112 is distributed around the outside of the rotor assembly 200, and one end of each tooth 112 is connected to the inner peripheral wall of the yoke 111, and the other end is spaced apart from the rotor assembly 200. Specifically, each tooth 112 is arranged in a circular array about the rotation axis 20 as a central axis, and the pitch between every two adjacent teeth 112 is the same along the circumferential direction m of the rotation axis 20. The stator assembly 100 may also include coil windings disposed around each tooth 112.

The maximum outer diameter of the stator core 110 isD ₃ . Wherein, in some embodiments, the maximum outer diameter of the stator core 110 may be the maximum outer diameter of the outer circumferential wall of the yoke 111; in other embodiments, when the outer peripheral wall of the yoke 111 is further provided with other structures, for example, the outer peripheral wall of the yoke 111 is further connected with external teeth, the maximum outer diameter of the stator core 110 is the maximum outer diameter of the external teeth. In this embodiment, the maximum outer diameter of the stator is exemplified as the maximum outer diameter of the yoke 111. When the outer circumferential wall of the stator core 110 is in a regular circular shape, D ₃ Is the diameter of the outer peripheral wall of the stator core 110. When the outer peripheral wall of the stator core 110 is irregularly annular, D ₃ Is the largest dimension of the outer peripheral wall of the stator core 110 in the direction perpendicular to the rotational axis 20. In actual measurement, the vernier caliper may be used to abut against two sides of the stator core 110 along a direction perpendicular to the rotation axis 20, and rotate the stator assembly 100 about the rotation axis 20 with respect to the vernier caliper, where the maximum degree of the vernier caliper is the maximum outer diameter D of the stator core 110 ₃ 。

Through demonstration, D ₂ /D ₃ Has a correlation with the stator winding ac loss and core loss distribution of the motor 10, in particular, when D ₂ /D ₃ When the ratio is small, the iron loss may be small, when D ₂ /D ₃ When the ratio is large, the alternating current loss of the stator winding can be smaller, only when D ₂ /D ₃ In a certain range, the distribution of the ac loss and the core loss of the stator winding is optimal, and the efficiency of the motor 10 is highest at this time, and when the distribution of the ac loss and the core loss of the stator winding of the motor 10 is better, the overall working efficiency of the motor 10 under heavy load working conditions and light load working conditions is better. Referring to fig. 1-2, 11-13, and 16, in this embodiment, by changing D ₂ /D ₃ The ratio is used to obtain the working efficiency of the motor 10 under heavy load working condition and light load working condition respectively. Through verification analysis, when D is more than or equal to 0.5% ₂ /D ₃ At 0.6 or less, e.g. D ₂ /D ₃ May be 0.5, 0.52, 0.54, 0.56, 0.58, 0.6, etc. When D is 0.5 to less than or equal to D ₂ /D ₃ At 0.6 or less, the magnetic field distribution in the permanent magnet motor 10 can be optimized so that the stator windings of the motor 10 are ac damagedThe loss and the iron loss are the smallest under various working conditions, so that the overall comprehensive efficiency of the motor 10 is better when the motor 10 has a heavy load working condition and a light load working condition. Referring to fig. 1-2, 11-13, and 16, when D ₂ /D ₃ When the load is 0.53 to 0.55, the heavy load efficiency of the motor 10 is in an ascending trend, and the light load efficiency of the motor 10 is in a descending trend; when D is ₂ /D ₃ When the load power is 0.61 to 0.63, the heavy load power of the motor 10 is slightly reduced, and the light load power of the motor 10 is reduced. In summary, the preferred location for integrated power occurs at D ₂ /D ₃ An intermediate section between 0.53 and 0.63. Proved by demonstration, when D is more than or equal to 0.5 ₂ /D ₃ Less than or equal to 0.6, the overall power of the motor 10 is preferred.

To further boost the overall power of the motor 10, in some embodiments, 0.53C ₂ /D ₃ Less than or equal to 0.57, e.g., D ₂ /D ₃ May be 0.53, 0.54, 0.55, 0.56, 0.57, etc. When D is 0.53-D ₂ /D ₃ At less than or equal to 0.57, the overall power of the motor 10 is better.

Referring to FIGS. 1-2, 11-13, and 16, in some embodiments 40mm C ₂ Less than or equal to 100mm, e.g. D ₂ 40mm, 50mm, 60mm, 70mm, 80mm, 90mm or 100mm, etc. When the diameter of the steel plate is 40mm or less than D ₂ When less than or equal to 100mm, can lead to D ₁ /D ₂ The correlation degree of the ratio to the comprehensive efficiency of the motor 10 is stronger, and the comprehensive efficiency of the motor 10 is improved, and meanwhile, the prediction of the comprehensive efficiency of the motor 10 is more accurate. Preferably 60 mm.ltoreq.D ₂ And the thickness is less than or equal to 80mm. For example, D ₂ 60mm, 65mm, 70mm, 75mm or 80mm, etc. When the diameter of the steel plate is 60mm or less than D ₂ When the diameter is less than or equal to 80mm, D can be made to be ₂ /D ₃ The correlation between the ratio of (2) and the comprehensive efficiency of the motor 10 is stronger, and the comprehensive efficiency of the motor 10 is further improved, and meanwhile, the prediction of the comprehensive efficiency of the motor 10 is more accurate.

In order to uniformly distribute the core loss of the motor 10 over the teeth 112 and the yoke 111 of the motor 10, the motor 10 is further optimally designed, referring to fig. 1-2, 11-13, and 16, in some embodiments, the number of teeth 112 of the stator core 110 is X, X is greater than or equal to 6, and the number X of teeth 112 may be greater than the number of permanent magnets 230. Each tooth 112 has a tenth wall surface 1123 and an eleventh wall surface 1124 arranged opposite to each other along the circumferential direction m of the rotation axis 20, and a minimum distance Wt of the tenth wall surface 1123 and the eleventh wall surface 1124 satisfies:

. Specifically, the above formula is equivalent to:

the method comprises the steps of carrying out a first treatment on the surface of the Wherein T is ₂ Is equal to the theoretical maximum arrangement space of the single tooth 112 in the circumferential direction m at a substantially middle position in the radial direction of the stator assembly 100. That is, wt is T of the theoretical maximum arrangement space of the intermediate position of the tooth 112 ₂ /4～2T ₂ Between/3, in particular, wt may be T ₂ /4、T ₂ /3、5T ₂ /12、T ₂ /2、7T ₂ /12, or 2T ₂ And/3, etc. This arrangement can uniformly distribute the core loss of the stator assembly 100 to the tooth 112 and yoke 111 positions of the motor 10.

In the present embodiment, the tenth wall 1123 and the eleventh wall 1124 are planar walls and are parallel to each other, and Wt is the distance between two corresponding points at any position of the tenth wall 1123 and the eleventh wall 1124. In other embodiments, the tenth wall 1123 and the eleventh wall 1124 are planar walls, and have an included angle (the included angle may be a machining error due to design requirements), at this time, wt is the minimum distance between the tenth wall 1123 and the eleventh wall 1124, and in specific operation, two measuring ends of the vernier caliper may be respectively abutted against the tenth wall 1123 and the eleventh wall 1124, so that the vernier caliper translates along the radial direction of the stator assembly 100, and at this time, the minimum degree of occurrence on the vernier caliper is the minimum distance Wt between the tenth wall 1123 and the eleventh wall 1124. In another embodiment, the tenth wall 1123 and the eleventh wall 1124 may have other irregular shapes, and the defining manner of Wt in this embodiment is the same as that of the previous embodiment, and will not be described here.

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

. Specifically, the above formula is equivalent to:

the method comprises the steps of carrying out a first treatment on the surface of the Wherein T is ₃ Is substantially equal to the maximum arrangement space of the side wall of the single permanent magnet 230 on the side facing away from the rotation axis 20 in the circumferential direction m, the minimum spacing Wx of the third end 1121 and the fourth end 1122 may be T ₃ /10、3T ₃ /25、7T ₃ /50、4T ₂ /25 or T ₃ And/5. The inter-shoe width of the stator core 110 has a large influence on the iron loss of the shoes and the sine degree of the air gap flux density, and affects the efficiency of the motor 10, and cogging torque and torque ripple. Cogging torque is the torque produced by the interaction between the permanent magnet 230 and the core when the windings of the permanent magnet motor 10 are not energized, and is caused by fluctuations in the tangential component of the interaction force between the permanent magnet 230 and the armature teeth. When Wx is in the range of T ₃ /10～T ₃ Between/5, the distribution of the air gap flux density can be changed, and the cogging torque of the motor 10 can be reduced.

Referring to fig. 1-2, 11-13, and 16, in some embodiments, the tooth 112 has a tenth wall 1123 along one side of the circumferential direction m of the rotational axis 20 and an eleventh wall 1124 along the other side of the circumferential direction m, the tenth wall 1123 having an intersection line 1125 with the second inner peripheral wall of the yoke 111. The boundary between the tenth wall 1123 and the inner peripheral wall of the yoke 111 may have a rounded or straight chamfer, and when the boundary between the tenth wall 1123 and the inner peripheral wall of the yoke 111 has a chamfer, the boundary 1125 is defined as a side line of the chamfer on the side away from the tenth wall 1123. In the present 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, external teeth may be further provided on the outer side of the yoke 111, the maximum outer diameter of the external teeth is the maximum outer diameter of the stator core 110), and the minimum distance We between the boundary line 1125 and the outer peripheral wall of the yoke 111 satisfies:

. Specifically, the above formula is equivalent to:

the method comprises the steps of carrying out a first treatment on the surface of the Wherein T is ₄ Is substantially equal to the maximum arrangement width of the stator core 110 in the radial direction, and the minimum distance We of the boundary line 1125 from the outer peripheral wall of the yoke portion 111 may be T ₄ /6、2T ₄ /9、5T ₄ /18 or T ₄ And/3, etc. When the value range of We is at T ₄ /6～T ₄ And/3, the distribution of the alternating current loss and the iron loss of the stator winding of the motor 10 can be optimized, so that the comprehensive efficiency of the motor 10 is improved.

Referring to FIG. 16, in one embodiment, when D ₂ The dimension is 74.8mm (error + -0.2 mm), D ₃ The dimensions 136-142mm, wt 9.95mm (error.+ -. 0.2 mm), we 7.3mm (error.+ -. 0.2 mm), wx 3-4.2mm, K4.4 mm (error.+ -. 0.2 mm), the ratio of the efficiency to the cost of the motor 10 is relatively good.

In another embodiment, when the inner diameter dimension of the inner core is 12.7mm (error.+ -. 0.2 mm), D ₃ 136-142mm in size, 4.3mm in Wr size (error + -0.2 mm), 2.3mm in Wa size (error + -0.2 mm), 8mm in Wm size (error + -0.2 mm), 24mm in radial length of permanent magnet (error + -0.2 mm), L ₃ The dimension is 4.4mm (error + -0.2 mm), L ₅ The dimension is 5.2mm (error + -0.2 mm), the firstThe radial dimension of the two limit protrusions is 0.3mm (error + -0.2 mm), the radial dimension of the first limit protrusion is 0.92mm (error + -0.2 mm), the ratio of the efficiency and the cost of the motor is highest, and the index requirements of demagnetization resistance and shaft voltage reduction of the motor are met.

Fig. 11-13, in some embodiments, the stator core 110 includes a second peripheral wall provided with a second injection molded slot 1111. In some embodiments, the stator assembly 100 further includes a second injection molded portion that encases the stator core 110 and the coil windings. Specifically, the second injection-molded portion fills the second injection-molded groove 1111, thereby fixing each lamination of the stator core 110.

Embodiments of the third aspect of the present invention also provide an air supply assembly comprising the motor 10 of any of the embodiments described above. The air supply assembly is used for driving air to move far towards a target direction, and can be particularly used for electric appliances such as electric fans, air conditioners, blowers, smoke exhaust fans, fresh air devices and the like.

Embodiments of the fourth aspect of the present invention also provide an air treatment device, which includes the air supply assembly described above. The air treatment device can be electric appliances such as an electric fan, an air conditioner, a blower, a smoke exhaust ventilator, a fresh air device and the like.

It should be noted that, if a directional indication (such as up, down, left, right, front, and rear … …) is included in the embodiment of the present invention, the directional indication is merely used to explain a relative positional relationship, a movement condition, and the like between the components in a specific posture, and if the specific posture is changed, the directional indication is correspondingly changed.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, if "and/or", "and/or" and/or "are used throughout, the meaning includes three parallel schemes, for example," a and/or B ", including a scheme, or B scheme, or a scheme where a and B meet simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.

The foregoing description of the preferred embodiments of the present invention should not be construed as limiting the scope of the invention, but rather should be understood to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following description and drawings or any application directly or indirectly to other relevant art(s).

Claims

1. A rotor assembly configured to rotate about a rotational axis, the rotor assembly comprising:

；

wherein: k is more than or equal to 1 and less than or equal to 5.

2. The rotor assembly of claim 1 wherein the rotor assembly comprises a plurality of rotor segments,

the inner iron core is annular arranged around the rotation axis, the inner iron core comprises a first inner peripheral wall close to the rotation axis and a first outer peripheral wall deviating from the rotation axis, along the second direction, the maximum distance Wr between the first inner peripheral wall and the first outer peripheral wall is as follows: wr is more than or equal to 2 xTs; or Wr is more than or equal to 2.5mm.

3. The rotor assembly of claim 1 wherein the rotor assembly comprises a plurality of rotor segments,

the minimum distance Wa between each core unit and the inner core in the radial direction of the rotor assembly satisfies: wa is more than or equal to 2 xTs; or Wa.gtoreq.2.5 mm.

4. The rotor assembly of claim 1 wherein the rotor assembly comprises a plurality of rotor segments,

the iron core unit is provided with a third wall surface positioned at one side along the circumferential direction, the third wall surface is provided with a limit protrusion, and the limit protrusion is suitable for abutting against the side wall of the permanent magnet, which faces away from or faces the rotation axis;

the limit protrusion is away from the maximum distance L from the end of the third wall surface to the third wall surface ₁ The method meets the following conditions: l (L) ₁ Not less than Ts; alternatively, the limit projection faces the side wall of the rotation axis to a minimum distance L between the side walls facing away from the rotation axis ₂ The method meets the following conditions: l (L) ₂ ≥Ts。

5. The rotor assembly of claim 1 wherein the rotor assembly comprises a plurality of rotor segments,

two of the iron core units are a first iron core unit and a second iron core unit, and the mounting groove is defined between the first iron core unit and the second iron core unit;

L ₃ less than or equal to 0.6 XWm; or 0.4 XWm.ltoreq.L ₃ ≤0.6×Wm。

6. The rotor assembly of claim 1 wherein the rotor assembly comprises a plurality of rotor segments,

7. The rotor assembly of claim 6 wherein the rotor assembly,

the first limiting protrusion is located at the end part of the fourth wall surface, which is away from the rotation axis, the second limiting protrusion is located at the end part of the fourth wall surface, which is close to the rotation axis, the third limiting protrusion is located at the end part of the fifth wall surface, which is away from the rotation axis, and the fourth limiting protrusion is located at the end part of the fifth wall surface, which is close to the rotation axis.

8. The rotor assembly of claim 1 wherein the rotor assembly comprises a plurality of rotor segments,

the permanent magnet extends out of one end or two ends of the mounting groove along the first direction.

9. The rotor assembly of claim 1 wherein the rotor assembly comprises a plurality of rotor segments,

the iron core unit is provided with a third wall surface attached to the permanent magnet, the third wall surface is provided with a first injection molding groove, and the first injection molding groove penetrates through the iron core unit along the first direction.

10. The rotor assembly of claim 1 wherein the rotor assembly comprises a plurality of rotor segments,

the rotor assembly further comprises a first injection molding part, wherein the first injection molding part is connected with the outer iron core and the inner iron core, and the injection molding part fills a gap between the outer iron core and the inner iron core.

11. An electric machine, comprising:

the rotor assembly of any one of claims 1-10; and

a stator assembly disposed about the rotor assembly.

12. The motor of claim 11, wherein the motor comprises a motor rotor,

the stator assembly comprises a stator core and a coil winding connected to the stator core, the stator core comprises a second peripheral wall, and the second peripheral wall is provided with a second injection molding groove.

13. The motor of claim 12, wherein the motor comprises a motor rotor,

the stator assembly further comprises a second injection molding part, and the second injection molding part wraps the stator core and the coil winding.

14. A blower assembly comprising the motor of claim 13.

15. An air treatment device comprising the blower assembly of claim 14.