CN219875239U - Magnetic steel sleeve, rotor assembly and motor - Google Patents

Abstract

The utility model discloses a magnetic steel sleeve, a rotor assembly and a motor, and relates to the technical field of permanent magnet motors. The magnetic steel sleeve comprises a tightening sleeve, a balance ring, a bearing spacer and a limiting protrusion; the balance ring is arranged at one end of the tightening sleeve to form a sleeve groove with the tightening sleeve; the bearing spacer is arranged on one side of the balance ring, which is opposite to the sleeve groove, in a protruding way, and a hole on the inner ring side of the balance ring is communicated with a hole on the inner ring side of the bearing spacer to form a shaft hole; the inner arm of the shaft hole is provided with a limiting bulge; wherein the tightening sleeve, the balance ring and the limit bulge are integrally arranged; one side of the balance ring, which is away from the sleeve groove, is provided with a balance mud setting groove, and the balance mud setting groove is positioned at a part between the bearing spacer and the outer ring of the balance ring. The utility model can improve the installation efficiency of the tightening sleeve and the balance ring.

Description

Magnetic steel sleeve, rotor assembly and motor

Technical Field

The utility model relates to the technical field of permanent magnet motors, in particular to a magnetic steel sleeve, a rotor assembly and a motor.

Background

The rotor generally comprises a rotating shaft, a rotor core and magnetic steel, wherein the rotor core is sleeved on the rotating shaft, the magnetic steel is stuck and fixed on the outer circle surface of the rotor core through glue, and the outer side of the magnetic steel is usually protected by a tightening sleeve in order to prevent the magnetic steel from flying out during rotation. Since the rotor involves dynamic balance calibration, the rotor is usually calibrated in a weighted or de-weighted manner. At present, a common rotor dynamic balance calibration mode is to sleeve a balance ring outside a tightening sleeve.

However, the existing tightening sleeve and the balancing ring need to be sleeved on the rotor in sequence, and the installation process is too complicated, so how to improve the installation efficiency of the tightening sleeve and the balancing ring is a technical problem which needs to be solved in the field.

Disclosure of Invention

In view of the above, the present utility model provides a magnetic steel sleeve, a rotor assembly and a motor for solving the above technical problems.

In order to solve the technical problems, the technical scheme adopted by the utility model is that the magnetic steel sleeve comprises a tightening sleeve, a balance ring, a bearing spacer and a limiting protrusion.

The balance ring is arranged at one end of the tightening sleeve to form a sleeve groove with the tightening sleeve. The bearing spacer is arranged on one side of the balance ring, which is opposite to the sleeve groove, in a protruding way, and the hole on the inner ring side of the balance ring is communicated with the hole on the inner ring side of the bearing spacer to form a shaft hole. The inner arm of the shaft hole is provided with a limiting bulge.

Wherein, tighten cover, balanced ring and spacing protruding an organic whole setting. One side of the balance ring, which is away from the sleeve groove, is provided with a balance mud setting groove, and the balance mud setting groove is positioned at a part between the bearing spacer and the outer ring of the balance ring.

In order to solve the technical problem, the utility model adopts another technical scheme that the rotor assembly comprises a rotating shaft, a rotor iron core, a plurality of magnetic steels, a first magnetic steel sleeve and a second magnetic steel sleeve, wherein the first magnetic steel sleeve and the second magnetic steel sleeve are both the magnetic steel sleeves.

The rotor core is sleeved on the rotating shaft. The plurality of magnetic steels are disposed around the rotor core on an outer ring side of the rotor core. The sleeve grooves of the first magnetic steel sleeve and the sleeve grooves of the second magnetic steel sleeve are respectively sleeved at two ends of the magnetic steels, and the shaft holes of the first magnetic steel sleeve and the shaft holes of the second magnetic steel sleeve are respectively fixedly sleeved at the outer sides of the two ends of the rotor core.

In order to solve the above technical problem, another technical solution adopted by the present utility model is to provide an electric motor, which includes a motor housing, a rotor assembly, a first bearing and a second bearing. The rotor assembly is the rotor assembly.

A front end cover and a rear end cover are arranged in the motor shell, and a rotor accommodating cavity is formed between the front end cover and the rear end cover. The rotor assembly comprises a rotor assembly rotating shaft, a rotor core, a plurality of magnetic steels, a first magnetic steel sleeve and a second magnetic steel sleeve, wherein the first magnetic steel sleeve and the second magnetic steel sleeve are arranged in a rotor accommodating cavity. The rotating shaft of the rotor assembly is respectively and rotatably connected with the front end cover and the rear end cover through a first bearing and a second bearing.

The first bearing is clamped between the front end cover and the bearing spacer of the first magnetic steel sleeve, and the outer diameter of the bearing spacer of the first magnetic steel sleeve is smaller than the inner diameter of the outer ring of the first bearing. The second bearing is clamped between the rear end cover and a bearing spacer of the second magnetic steel sleeve, and the outer diameter of the bearing spacer of the second magnetic steel sleeve is smaller than the inner diameter of an outer ring of the second bearing.

The beneficial effects are that: compared with the prior art, the magnetic steel sleeve adopts a mode that the tightening sleeve and the balance ring are sequentially sleeved on the rotor, and the tightening sleeve, the balance ring and the limit protrusions are integrally arranged in the magnetic steel sleeve, so that the magnetic steel sleeve can be integrally formed, the mounting steps of the balance ring and the tightening sleeve can be omitted, and the mounting efficiency of the tightening sleeve and the balance ring can be improved.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of the motor of the present utility model;

FIG. 2 is an enlarged schematic view of area A of FIG. 1;

FIG. 3 is an enlarged schematic view of region B of FIG. 1;

FIG. 4 is a schematic view of the rotor assembly of the motor of the present utility model;

FIG. 5 is an enlarged schematic view of region C of FIG. 4;

FIG. 6 is a schematic view of the oblique side of the magnetic steel sleeve in the motor of the present utility model;

FIG. 7 is a schematic view of the side of the magnetic steel sleeve facing away from the binding sleeve in the motor of the present utility model;

fig. 8 is an end view schematically showing a rotor core in the motor of the present utility model.

Reference numerals illustrate:

10. a motor; 100. a motor housing, 200, a rotor assembly; 300. a bearing; 300a, a first bearing; 300b, a second bearing;

110. a front end cover; 120. a rear end cover; 130. a rotor accommodation chamber; 140. a bearing limit groove;

210. a rotating shaft; 220. a rotor core; 221. a fitting hole; 222. a magnetic steel limit groove; 230. magnetic steel; 240. a magnetic steel sleeve; 240a, a first magnetic steel sleeve; 240b, a second magnetic steel sleeve;

211. a limit fit groove; 211a, a first limit fit groove; 211b, a second limit fit groove; 241. tightening the sleeve; 242. a balance ring; 243. bearing spacer bush; 244. a limit protrusion; 244a, a first limit protrusion; 244b, a second limit protrusion; 245. a sleeve groove; 246. a balance mud setting groove; 247. a first distracted mating part; 248. a second expansion fitting portion;

21. a raised slug; 22. a balance ring body; 23. a surrounding wall; 24. a partition wall; 25. the balance mud is provided with a subslot; 26. and the shaft hole.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the description of the present utility model, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, merely to facilitate description of the present utility model and simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Referring to fig. 1-3, the motor 10 of the present utility model includes a motor housing 100, a rotor assembly 200, a first bearing 300a, and a second bearing 300b.

A front end cover 110 and a rear end cover 120 are arranged in the motor housing 100, and a rotor accommodating cavity 130 is formed between the front end cover 110 and the rear end cover 120. The rotor assembly 200 is disposed in the rotor accommodating chamber 130. The rotor assembly 200 is rotatably coupled to the front and rear caps 110 and 120 by first and second bearings 300a and 300b, respectively. As such, the rotor assembly 200 is capable of rotating relative to the motor housing 100.

Referring to fig. 4-5 in combination with fig. 1-3, the rotor assembly 200 includes a rotating shaft 210, a rotor core 220, a plurality of magnetic steels 230, a first magnetic steel sleeve 240a, and a second magnetic steel sleeve 240b.

The rotor core 220 is sleeved on the rotating shaft 210. A plurality of magnetic steels 230 are provided around the rotor core 220 on the outer-ring side of the rotor core 220. The first and second magnetic steel sleeves 240a and 240b are respectively sleeved into both ends of the plurality of magnetic steels 230. The first bearing 300a is sandwiched between the front cover 110 and the first magnetic steel sleeve 240a, and the second bearing 300b is sandwiched between the rear cover 120 and the second magnetic steel sleeve 240b.

In the above manner, the front end cover 110, the first bearing 300a, the first magnetic steel sleeve 240a, the rotor core 220, the second magnetic steel sleeve 240b, the second bearing 300b and the rear end cover 120 are abutted in the axial direction of the rotating shaft 210, so that the first bearing 300a, the first magnetic steel sleeve 240a, the rotor core 220, the second magnetic steel sleeve 240b and the second bearing 300b can be prevented from being offset relative to the front end cover 110 or the rear end cover 120 in the axial direction of the rotating shaft 210, and the relative positions of the first bearing 300a, the first magnetic steel sleeve 240a, the second magnetic steel sleeve 240b of the rotor core 220 and the second bearing 300b in the axial direction of the rotating shaft 210 are stable.

Further, referring to fig. 6-7 in combination with fig. 4-5, the rotating shaft 210 is provided with a limit fit groove 211, and the magnetic steel sleeves 240 in both the first magnetic steel sleeve 240a and the second magnetic steel sleeve 240b comprise a tightening sleeve 241, a balancing ring 242, a bearing spacer 243 and a limit protrusion 244.

The balancing ring 242 is disposed at one end of the tightening sleeve 241 to form a sleeve slot 245 with the tightening sleeve 241, and the sleeve slot 245 is sleeved into the end of the rotor core 220 to sleeve the plurality of magnetic steels 230, so as to prevent the magnetic steels 230 from flying out when the rotor assembly 200 rotates. And the hole at the inner ring side of the balance ring 242 is communicated with the hole at the inner ring side of the bearing spacer 243 to form a shaft hole 26, and the shaft hole 26 is fixedly sleeved on the rotating shaft 210. The bearing spacer 243 is convexly arranged on the side of the balance ring 242 opposite to the sleeve groove 245, so as to clamp the bearing 300 in cooperation with the motor housing 100. The inner arm of the shaft hole 26 is provided with a limit protrusion 244, the bearing 300 is provided with a limit fitting groove 211 corresponding to the limit protrusion 244, and the limit protrusion 244 is inserted into the limit fitting groove 211 to position the magnetic steel sleeve 240 in the axial direction of the rotating shaft 210. Wherein, the tightening sleeve 241, the balance ring 242 and the limit protrusion 244 are integrally provided. The balance ring 242 is provided with a balance mud setting groove 246 on a side facing away from the sleeve groove 245, and the balance mud setting groove 246 is located at a portion between the bearing spacer 243 and the outer ring of the balance ring 242, so that dynamic balance weight can be realized by pasting balance mud in the balance mud setting groove 246.

By the mode, compared with the prior art, the method that the tightening sleeve and the balance ring are arranged in a split mode and sequentially sleeved on the rotor is adopted, the tightening sleeve 241, the balance ring 242 and the limiting protrusion 244 in the magnetic steel sleeve are integrally arranged, so that the magnetic steel sleeve can be integrally formed, the mounting step of the balance ring 242 and the tightening sleeve 241 can be omitted, and the mounting efficiency of the tightening sleeve 241 and the balance ring 242 can be improved.

In addition, because the tightening sleeve 241, the balance ring 242 and the limiting protrusion 244 are integrally arranged, the tightening sleeve 241, the balance ring 242 and the limiting protrusion 244 are integrally formed by uniform materials, so that the material consistency of the magnetic steel sleeve 240 can be improved, the production cost can be reduced, and the production efficiency can be improved.

Referring to fig. 4-5 in conjunction with fig. 1-3, the rotating shaft 210, the rotor core 220, the plurality of magnetic steels 230, the first magnetic steel sleeve 240a and the second magnetic steel sleeve 240b of the rotor assembly 200 are disposed in the rotor accommodating cavity 130. The sleeve grooves 245 of the first magnetic steel sleeve 240a and the sleeve grooves 245 of the second magnetic steel sleeve 240b are respectively sleeved at two ends of the plurality of magnetic steels 230. The shaft hole 26 of the first magnetic steel sleeve 240a and the shaft hole 26 of the second magnetic steel sleeve 240b are fixedly sleeved on the outer side portions of the rotating shaft 210 at the two ends of the rotor core 220, respectively. The rotation shaft 210 of the rotor assembly 200 is rotatably coupled to the front and rear caps 110 and 120 through a first bearing 300a and a second bearing 300b, respectively. The first bearing 300a is sandwiched between the front end cover 110 and the bearing spacer 243 of the first magnetic steel sleeve 240a, and the outer diameter of the bearing spacer 243 of the first magnetic steel sleeve 240a is smaller than the inner diameter of the outer ring of the first bearing 300 a. The second bearing 300a is interposed between the rear end cap 120 and the bearing spacer 243 of the second magnetic steel sleeve 240b, and the bearing spacer 243 of the second magnetic steel sleeve 240b has an outer diameter smaller than an inner diameter of the outer ring of the second bearing 300b. In this way, since the outer diameter of the bearing spacer 243 is smaller than the inner diameter of the outer ring of the corresponding bearing 300, interference of the bearing spacer 243 with rotation of the outer ring of the bearing 300 relative to the inner ring of the bearing 300 can be avoided.

Alternatively, referring to fig. 1-3, the front end cover 110 and the rear end cover 120 are correspondingly provided with bearing limit grooves 140, and the corresponding bearings 300 are limited in the bearing limit grooves 140, for example, the first bearings 300a are limited in the bearing limit grooves 140 of the front end cover 110, and the second bearings 300b are limited in the bearing limit grooves 140 of the rear end cover 120. The outer ring of the bearing 300 abuts against the bottom wall of the bearing limit groove 140, and the inner ring of the bearing 300 is spaced from the bottom wall of the bearing limit groove 140 and abuts against the corresponding bearing spacer 243. In this way, the position of the bearing 300 in the axial direction of the rotating shaft 210 can be fixed without affecting the rotation of the outer ring of the bearing 300 relative to the inner ring.

Further, referring to fig. 6 and 8 in combination with fig. 4-5, the end face of the rotor core 220 is provided with an engaging hole 221, the sleeve groove 245 is provided with a protruding insert 21, the protruding insert 21 is protruding to be arranged in the balance ring 242, and the protruding insert 21 is inserted into the engaging hole 221. Illustratively, the raised inserts 21 are regular or irregular protrusions. Wherein the regular convex shape includes, but is not limited to, columnar, conical, hemispherical, or mesa shape. In this way, the relative positions of the rotor core 220 and the magnetic steel sleeve 240 can be further fixed, so as to avoid the rotor core 220 from separating from the magnetic steel sleeve 240. Alternatively, the protruding insert 21 is interference-fitted with the fitting hole 221, so that the connection of the protruding insert 21 with the fitting hole 221 can be made more firm.

Optionally, referring to fig. 8 in conjunction with fig. 4, a plurality of magnetic steel limiting grooves 222 are disposed on an outer ring of the rotor core 220, the plurality of magnetic steel limiting grooves 222 are disposed at intervals around the circumference of the rotor core 220, and each magnetic steel limiting groove 222 is correspondingly provided with a magnetic steel 230. This can further fix the relative positions of the plurality of magnetic steels 230 in the circumferential direction around the rotor core 220.

Further, referring to fig. 6-7 in conjunction with fig. 4, the gimbal 242 includes the gimbal body 22 and the enclosure wall 23.

The balance ring body 22 is disposed at one end of the tightening sleeve 241 and encloses a sleeve slot 245 with the tightening sleeve 241. The enclosing wall 23 is arranged around the bearing spacer 243 in a protruding manner on the side of the balance ring main body 22 facing away from the tightening sleeve 241 and is spaced from the bearing spacer 243, so as to form a balance mud setting groove 246 between the bearing spacer 243 and the enclosing wall 23.

In the above manner, the surrounding wall 23 can stop the balance mud located in the balance mud setting groove 246, so that the balance mud in the balance mud setting groove 246 can be prevented from flying out of the balance mud setting groove 246 during the rotation of the rotor assembly 200. Optionally, the inner surface of the balancing mud setting groove 246 is roughened so as to provide sufficient friction to support the application of balancing mud within the balancing mud setting groove 246.

Further, referring to fig. 7 in combination with fig. 4, the balance ring 242 includes a plurality of partition walls 24, the plurality of partition walls 24 being disposed within the balance mud setting groove 246 to divide the balance mud setting groove 246 into a plurality of balance mud setting sub-grooves 25. A plurality of balance mud setting subslots 25 are distributed around the axial direction of the shaft hole 26. In this manner, dynamic balancing of the rotor assembly 200 may be achieved by selectively disposing the balancing mud on a portion of the balancing mud disposing sub-tank 25.

Further, referring to fig. 6 to 7 in combination with fig. 4 to 5, the limit fitting groove 211 includes a first limit fitting groove 211a and a second limit fitting groove 211b spaced around the outer ring of the rotating shaft 210, and the limit protrusion 244 includes a first limit protrusion 244a and a second limit protrusion 244b. The first and second limiting protrusions 244a and 244b are disposed in the shaft hole 26 at intervals along the circumferential direction of the shaft hole 26. The diameter of the inner circle between the first and second spacing protrusions 244a and 244b is smaller than the diameter of the rotation shaft 210 such that the first spacing protrusion 244a is inserted into the first spacing fit groove 211a and the second spacing protrusion 244b is inserted into the second spacing fit groove 211b. Wherein, the shaft hole 26 can be elastically expanded to expand the interval between the first and second limit protrusions 244a and 244b in the radial direction of the shaft hole 26. Illustratively, the magnetic steel sleeve 240 may be a plastic piece. For example, the magnetic steel sleeve 240 includes, but is not limited to, an injection molded piece to allow the shaft bore 26 to elastically expand.

In the above manner, the elastic expansion of the shaft hole 26 can be optionally utilized to expand the interval between the first and second limit protrusions 244a and 244b in the radial direction of the shaft hole 26 and accumulate the deformation resistance. The radial interval expansion along the shaft hole 26 between the first limit protrusion 244a and the second limit protrusion 244b can avoid the rotating shaft 210, so that the rotating shaft 210 can be more conveniently placed into the shaft hole 26. The accumulated deformation resistance can be released to retract the elastically-expanded shaft hole 26, thereby retracting the enlarged interval between the first and second limit protrusions 244a and 244b in the radial direction of the shaft hole 26, thereby inserting the first limit protrusion 244a into the first limit fitting groove 211a and the second limit protrusion 244b into the second limit fitting groove 211b. Thus, compared with the prior art that the vertical tightening sleeve and the balance ring layer sleeve are arranged on the rotor in a hot sleeve mode, the installation of the magnetic steel sleeve 240 is realized through the elastic expansion and elastic contraction processes of the shaft hole 26, and the method is more convenient and quick and has lower material cost.

Alternatively, referring to fig. 6-7 in conjunction with fig. 4-5, in one example, both the first and second stop bumps 244a, 244b extend in an arc shape around the circumference of the shaft bore 26. Further, the first and second limiting protrusions 244a and 244b are symmetrically disposed at both sides of the axis of the shaft hole 26. So first spacing protruding 244a inserts first spacing mating groove 211a, and second spacing protruding 244b inserts second spacing mating groove 211b, can make first spacing protruding 244a and second spacing protruding 244b press from both sides tight pivot 210's both sides, and then can more firmly fix magnet steel cover 240 in the axial of pivot 210, hoop and radial position.

Further, referring to fig. 6-7 in conjunction with fig. 4-5, the diameter of the shaft hole 26 is larger than that of the rotating shaft 210, and a first opening matching portion 247 and a second opening matching portion 248 are disposed at one end of the bearing spacer 243 facing away from the tightening sleeve 241. The first and second spreader engagement portions 247, 248 are circumferentially spaced about the shaft aperture 26.

The reference plane is defined as a plane (not shown) perpendicular to the axial direction of the shaft hole 26, and is an imaginary plane. The projection of the first expanding engaging portion 247 in the reference plane is on the same side of the axis of the shaft hole 26 as the projection of the first limiting projection 244a in the reference plane, and the projection of the second expanding engaging portion 248 in the reference plane is on the same side of the axis of the shaft hole 26 as the projection of the second limiting projection 244b in the reference plane. The first opening matching portion 247 and the second opening matching portion 248 are used for connecting an opening tool (not shown), so that the shaft hole 26 can be elastically expanded under the driving of the opening tool. So, under the drive of strutting the frock, can laborsaving and convenient drive first strutting cooperation portion 247 and second strutting cooperation portion 248 move to the direction that keeps away from mutually, and then make shaft hole 26 expand to the installation of convenient pivot 210. Exemplary distraction tools include, but are not limited to, dilators.

Optionally, in an example, the first expanding mating portion 247 and the second expanding mating portion 248 are adaptor holes, and the expanding tool is correspondingly provided with an adaptor, and the adaptor holes are used for connecting the adaptor, for example, the adaptor holes are in interference fit with the adaptor, and are in threaded fit with the adaptor.

Optionally, in another example, the first expanding mating portion 247 and the second expanding mating portion 248 are connectors, and the expanding tool is correspondingly provided with a connector hole, and the connectors are used for connecting the connector hole, for example, the connectors are in interference fit with the connector hole, and are in threaded fit with the connector hole.

Alternatively, in still another example, the first and second expanding mating portions 247 and 248 are abutment protrusions, and two sides of the expanding head on the expanding tool may abut against the abutment protrusion as the first expanding mating portion 247 and the abutment protrusion as the second expanding mating portion 248, respectively, so as to drive the abutment protrusion as the first expanding mating portion 247 and the abutment protrusion as the second expanding mating portion 248 to be away from each other in the radial direction of the shaft hole 26, so as to expand the shaft hole 26.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the utility model.

Claims (10)

1. The magnetic steel sleeve is characterized by comprising a tightening sleeve, a balance ring, a bearing spacer and a limiting protrusion;

the balance ring is arranged at one end of the tightening sleeve to form a sleeve groove with the tightening sleeve; the bearing spacer is arranged on one side of the balance ring, which is opposite to the sleeve groove, in a protruding way, and the hole on the inner ring side of the balance ring is communicated with the hole on the inner ring side of the bearing spacer to form a shaft hole; the inner arm of the shaft hole is provided with a limiting protrusion;

wherein the tightening sleeve, the balance ring and the limit protrusion are integrally arranged; and a balance mud setting groove is formed in one side, away from the sleeve groove, of the balance ring, and the balance mud setting groove is positioned at a part between the bearing spacer and the outer ring of the balance ring.

2. The magnetic steel sleeve of claim 1, wherein a raised insert is disposed in the sleeve groove, the raised insert being disposed in the gimbal in a raised manner.

3. The magnetic steel jacket of claim 2, wherein the raised inserts are columnar, conical, hemispherical, or mesa-shaped.

4. The magnetic steel sleeve according to claim 1 or 2, wherein the balance ring comprises:

the balance ring main body is arranged at one end of the tightening sleeve and surrounds the tightening sleeve to form a sleeve groove;

the surrounding baffle wall surrounds the bearing spacer is arranged on one side of the balance ring main body, which is opposite to the tightening sleeve, in a protruding mode, and is arranged at intervals with the bearing spacer, so that a balance mud setting groove is formed between the bearing spacer and the surrounding baffle wall.

5. The magnetic steel sleeve according to claim 4, wherein the limiting protrusions comprise a first limiting protrusion and a second limiting protrusion, the first limiting protrusion and the second limiting protrusion are arranged in the shaft hole at intervals along the circumferential direction of the shaft hole, and the diameter of an inner circle between the first limiting protrusion and the second limiting protrusion is smaller than the diameter of the rotating shaft;

the shaft hole can be elastically expanded so that the interval between the first limit protrusion and the second limit protrusion along the radial direction of the shaft hole is enlarged.

6. The magnetic steel bushing of claim 5, wherein the first and second stop tabs each extend in an arc shape around the circumference of the shaft bore.

7. The magnetic steel sleeve of claim 6, wherein the first and second limit protrusions are symmetrically disposed on both sides of an axis of the shaft hole.

8. The magnetic steel sleeve according to claim 5, wherein the diameter of the shaft hole is larger than that of the rotating shaft, and a first stretching matching part and a second stretching matching part are arranged at one end of the bearing spacer facing away from the tightening sleeve; the first opening matching part and the second opening matching part are arranged at intervals around the annular direction of the shaft hole;

wherein, a reference plane is defined as a plane perpendicular to the axial direction of the shaft hole, and then the projection of the first expansion matching part in the reference plane and the projection of the first limit protrusion in the reference plane are positioned on the same side of the axis of the shaft hole, and the projection of the second expansion matching part in the reference plane and the projection of the second limit protrusion in the reference plane are positioned on the same side of the axis of the shaft hole; the first opening matching part and the second opening matching part are used for connecting an opening tool, so that the shaft hole can be elastically expanded under the drive of the opening tool.

9. A rotor assembly, characterized in that the rotor assembly comprises a rotating shaft, a rotor core, a plurality of magnetic steels, a first magnetic steel sleeve and a second magnetic steel sleeve, wherein the first magnetic steel sleeve and the second magnetic steel sleeve are the magnetic steel sleeves according to any one of claims 1-8;

the rotor iron core is sleeved on the rotating shaft; the plurality of magnetic steels are arranged on the outer ring side of the rotor core around the rotor core; the sleeve grooves of the first magnetic steel sleeve and the sleeve grooves of the second magnetic steel sleeve are sleeved at two ends of the magnetic steels respectively, and the shaft holes of the first magnetic steel sleeve and the shaft holes of the second magnetic steel sleeve are fixedly sleeved at the parts of the rotating shaft, which are positioned at the outer sides of the two ends of the rotor core, respectively.

10. An electric machine comprising a machine housing, a rotor assembly, a first bearing and a second bearing; the rotor assembly of claim 9;

a front end cover and a rear end cover are arranged in the motor shell, and a rotor accommodating cavity is formed between the front end cover and the rear end cover; the rotating shaft, the rotor iron core, the plurality of magnetic steels, the first magnetic steel sleeve and the second magnetic steel sleeve of the rotor assembly are arranged in the rotor accommodating cavity; the rotating shaft of the rotor assembly is respectively and rotatably connected with the front end cover and the rear end cover through the first bearing and the second bearing;

the first bearing is clamped between the front end cover and the bearing spacer of the first magnetic steel sleeve, and the outer diameter of the bearing spacer of the first magnetic steel sleeve is smaller than the inner diameter of the outer ring of the first bearing; the second bearing is clamped between the rear end cover and the bearing spacer of the second magnetic steel sleeve, and the outer diameter of the bearing spacer of the second magnetic steel sleeve is smaller than the inner diameter of the outer ring of the second bearing.