A rotor, an electric machine, an air compressor and a method of assembling a rotor

Abstract

The application provides a rotor, a motor, an air compressor and an assembling method of the rotor. The application provides a rotor applied to a motor. The rotor comprises a rotating shaft and an insulating heat conducting sleeve. The rotating shaft is provided with a bearing position. The surface of the bearing position is provided with a convex thread structure. The insulating heat conducting sleeve is provided on the bearing position in an interference mode, so that the shaft current flowing through the bearing can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically relating to a rotor, a motor, an air compressor, and a method for assembling the rotor. Background Technology

[0002] As a core power component of industrial compression systems, the reliability of air compressor motors directly impacts production efficiency. Currently, motors generally face two major technical bottlenecks: bearing erosion caused by shaft current and overheating failure due to insufficient heat dissipation. Shaft current issues originate from the electromagnetic induction of the shaft by the stator magnetic field. Shaft current not only reduces bearing life but also generates heat in the bearing, degrading motor performance.

[0003] Reducing the shaft current flowing through the bearing is a technical solution that urgently needs to be solved. Summary of the Invention

[0004] Therefore, the present invention provides a rotor, a motor, an air compressor, and a method for assembling the rotor, which can reduce the shaft current flowing through the bearing.

[0005] In a first aspect, the present invention provides a rotor for use in an electric motor, the rotor comprising a shaft and an insulating heat-conducting sleeve, the shaft having a bearing seat, the surface of the bearing seat having a raised threaded structure, and the insulating heat-conducting sleeve being interference-fitted onto the bearing seat.

[0006] In some embodiments, the insulating heat-conducting sleeve is provided with a plurality of pore structures that extend along the radial direction of the insulating heat-conducting sleeve.

[0007] In some embodiments, the inner surface of the insulating heat-conducting sleeve is provided with an inner groove extending along its own axial direction, and there are raised stripes between two adjacent inner grooves.

[0008] The depth of the inner groove is equal to the thread height of the thread structure, and the lowest point of the inner groove and the highest point of the thread are located on the same cylindrical surface.

[0009] or,

[0010] The lowest point of the thread and the highest point of the raised stripe are located on the same cylindrical surface, and the height of the raised stripe is greater than the height of the thread of the thread structure.

[0011] In some embodiments, each end of the rotating shaft is provided with a bearing seat, the shaft section between the two bearing seats is a middle section, the diameter of the middle section is larger than the diameter of the bearing seat, and the surface of the middle section is provided with an outer groove that penetrates the middle section along the axial direction of the middle section.

[0012] In some embodiments, the outer surface of the intermediate section is covered with a moving iron core, a first ventilation hole is provided inside the moving iron core, and multiple fins are provided at both ends of the moving iron core. The openings at both ends of the first ventilation hole are directed to the two ends of the moving iron core and located between two adjacent fins.

[0013] In some embodiments, the fins on both sides of the opening at one end of the first ventilation hole are respectively the first fin and the second fin, and the fins on both sides of the opening at the other end of the first ventilation hole are respectively the third fin and the fourth fin. In the axial projection of the moving iron core, the fins at both ends of the moving iron core completely overlap, and the projections of the first fin, the second fin, and the third fin and the fourth fin in the axial direction overlap by at most one.

[0014] In some embodiments, multiple first ventilation holes are provided, with some first ventilation holes having a forward spiral direction and others having a reverse spiral direction.

[0015] In some embodiments, a portion of the first ventilation hole is linear, and the linear first ventilation hole is parallel to the axis of the rotating shaft.

[0016] Secondly, the present invention also provides an electric motor, including a stator core and the rotor, wherein the stator core is provided with a second ventilation hole extending along the axial direction.

[0017] Thirdly, the present invention also provides an air compressor, including the aforementioned motor.

[0018] Fourthly, the present invention also provides an assembly method for a rotor, characterized in that the assembly method includes: rotating the insulating heat-conducting sleeve onto the bearing position along the rotation direction of the threaded structure.

[0019] This invention alters the flow path of the shaft current by installing an insulating and heat-conducting sleeve at the bearing location, preventing the shaft current from passing through the bearing, thus effectively avoiding electrical corrosion of the bearing and reducing the bearing temperature. Attached Figure Description

[0020] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the rotor structure according to an embodiment of the present invention;

[0022] Figure 2This is an embodiment of the present invention. Figure 1 A top-down view;

[0023] Figure 3 This is a schematic diagram of the moving iron core according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of an insulating heat-conducting sleeve according to an embodiment of the present invention;

[0025] Figure 5 This is an embodiment of the present invention. Figure 4 A top-down view;

[0026] Figure 6 This is a schematic diagram of the stator structure according to an embodiment of the present invention;

[0027] Figure 7 This is a first axial schematic diagram of the housing according to an embodiment of the present invention;

[0028] Figure 8 This is a second axial schematic diagram of a housing with legs provided according to an embodiment of the present invention;

[0029] Figure 9 This is a schematic diagram of a motor according to an embodiment of the present invention;

[0030] Figure 10 This is a schematic diagram of the first airflow inside the motor according to an embodiment of the present invention;

[0031] Figure 11 This is a schematic diagram of the second airflow inside the motor according to an embodiment of the present invention;

[0032] Figure 12 This is a schematic diagram of the current flow path inside the motor shaft according to an embodiment of the present invention;

[0033] Figure 13 This is a schematic diagram of the current flow in a motor shaft in the prior art;

[0034] The attached figures are labeled as follows:

[0035] 1. Rotor; 101. Moving iron core; 1011. Threaded channel; 2. Stator; 201. Stationary iron core; 3. Insulating and heat-conducting sleeve; 301. Inner groove; 302. Raised stripes; 4. Shaft; 401. Bearing seat; 4011. Threaded structure; 402. Intermediate section; 4021. Outer groove; 501. First ventilation hole; 502. Second ventilation hole; 6. Housing; 7. Exhaust hole; 8. Fins. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0038] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0039] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0040] In a highly competitive market, air compressors are among the most important production equipment in factories for many companies. With the continuous improvement of air compressor manufacturing capabilities, they have evolved from the traditional piston type to the screw type. Screw air compressors are used in applications requiring cleanliness, ventilation, low dust levels, and good sound insulation. Their structure and performance require high efficiency, low energy consumption, and miniaturization. This places certain demands on the selection and design of their drive motors, requiring careful consideration of factors such as starting torque, operating efficiency, heat dissipation performance, and speed regulation capabilities.

[0041] As a core power component of industrial compression systems, the operational reliability of air compressor motors directly impacts production efficiency. Currently, motors generally face two major technical bottlenecks: bearing erosion caused by shaft current and overheating failure due to insufficient heat dissipation. The shaft current problem originates from the electromagnetic induction of the shaft by the stator magnetic field. While existing protection solutions (such as insulated bearings) can suppress the current, they suffer from drawbacks such as high cost. The mainstream heat dissipation method for air compressor motors in the industry is oil-cooled housing. The motor housing has an oil inlet and an oil outlet. The housing and the air compressor system form a circuit. During operation, under the influence of pressure difference, cooled low-temperature oil flows into the housing through the inlet and out through the outlet via the cooling channels within the housing, carrying away the heat generated by the motor.

[0042] The energy-saving and consumption-reducing motor technology described in this application belongs to the strategic emerging industries sector.

[0043] Firstly, such as Figures 1-12 As shown, the present invention provides a rotor 1 for use in an electric motor. The rotor 1 includes a rotating shaft 4 and an insulating and heat-conducting sleeve 3. The rotating shaft 4 is provided with a bearing seat 401. The surface of the bearing seat 401 is provided with a raised thread structure 4011. The insulating and heat-conducting sleeve 3 is interference-fitted onto the bearing seat 401.

[0044] By installing an insulating heat-conducting sleeve 3 at bearing position 401, the shaft current loop is interrupted by the insulating heat-conducting sleeve 3, completely eliminating bearing electrolytic corrosion caused by shaft current. The current is redirected to the "motor housing → grounding wire → power supply" path, reducing the risk of bearing electrolytic corrosion to zero. The insulating heat-conducting sleeve 3 has both insulation and heat conduction functions; heat from bearing position 401 can be conducted outward through the insulating heat-conducting sleeve 3, reducing the bearing operating temperature. Compared to existing insulated bearings, this application can reduce or even eliminate bearing shaft current by installing the insulating heat-conducting sleeve 3, effectively reducing costs. This, in turn, reduces the heat generated by the bearing and the motor.

[0045] Furthermore, the insulating and heat-conducting sleeve 3 can be made of epoxy resin. Epoxy resin has good insulation properties. Epoxy resin with insulating fillers such as boron nitride and aluminum oxide not only has good insulation properties but also significantly improved thermal conductivity. In addition, epoxy resin also has a certain degree of toughness, which can play a role in damping the rotation of rotor 1.

[0046] like Figure 1 and Figure 2 As shown, the connection is reliable through a combination of interference fit and threaded fastening. The raised thread provides axial positioning, while the interference fit provides circumferential fastening, resulting in a stable assembly that is not easily loosened.

[0047] Furthermore, the mechanical ball bearing is fitted onto the epoxy resin ring with an interference fit. Since the shaft current must form a loop, the original current path is: (e.g.) Figure 12 (As shown) Stator 2 winding → Shaft 4 → Bearing → Housing 6 → Grounding wire → Power supply. The current path in this application is: Motor housing → Grounding wire → Power supply ( Figure 12 As shown in the diagram, the risk of bearing electrolytic corrosion is zero. A smaller shaft current means less heat generation.

[0048] Preferred, such as Figure 4 and Figure 5 As shown, the insulating heat-conducting sleeve 3 is provided with a plurality of pore structures, which extend along the radial direction of the insulating heat-conducting sleeve 3.

[0049] The radial pores allow the heat generated by the bearing seat 401 to quickly pass through the insulating heat-conducting sleeve 3 radially and dissipate outwards, significantly improving the axial heat dissipation efficiency. The radial pores also reduce the thermal resistance of the insulating heat-conducting sleeve 3 itself. The porous structure increases the effective cross-sectional area for heat conduction, resulting in a higher equivalent thermal conductivity compared to solid epoxy resin.

[0050] The porous structure also provides space for the insulating heat-conducting sleeve 3 to deform, preventing the insulating heat-conducting sleeve 3 from being damaged by excessive compression; at the same time, it also increases the shock absorption effect of the insulating heat-conducting sleeve 3.

[0051] Preferred, such as Figure 4 and Figure 5 As shown, the inner surface of the insulating heat-conducting sleeve 3 is provided with an inner groove 301 extending along its own axial direction, and there are raised stripes 302 between two adjacent inner grooves 301.

[0052] The depth of the inner groove 301 is equal to the thread height of the thread structure 4011, and the lowest point of the inner groove 301 and the highest point of the thread are located on the same cylindrical surface.

[0053] or,

[0054] The lowest point of the thread and the highest point of the raised stripe 302 are located on the same cylindrical surface, and the height of the raised stripe 302 is greater than the height of the thread of the thread structure 4011.

[0055] In Example 1, the depth of the inner groove 301 is equal to the thread height of the thread structure 4011. The lowest point of the inner groove 301 and the highest point of the thread are located on the same cylindrical surface. This ensures that the highest point of the raised stripe 302 and the lowest point of the thread are also on the same cylindrical surface, resulting in a sufficiently tight connection between the insulating heat-conducting sleeve 3 and the bearing seat 401. Furthermore, since the inner groove 301 extends axially while the thread structure 4011 extends circumferentially, multiple independent micro-spaces (the micro-spaces formed by the interlacing of the axially extending raised stripe 302 and the circumferentially extending thread) are formed between the insulating heat-conducting sleeve 3 and the bearing seat 401. These micro-spaces effectively absorb vibrations, further improving the stability of motor operation.

[0056] In Example 2, the lowest point of the thread and the highest point of the raised stripe 302 are located on the same cylindrical surface, which blocks the thread groove between two adjacent threads in the circumferential direction; the height of the raised stripe 302 is greater than the height of the thread, which forms an axially extending through hole between the insulating heat-conducting sleeve 3 and the bearing seat 401. This through hole constitutes an air circulation channel, which can accelerate heat dissipation.

[0057] Preferred, such as Figure 1 and Figure 2 As shown, each end of the rotating shaft 4 is provided with a bearing seat 401, and the shaft section between the two bearing seats 401 is a middle section 402. The diameter of the middle section 402 is larger than the diameter of the bearing seat 401, and the surface of the middle section 402 is provided with an outer groove 4021 that runs through the middle section 402 along the axial direction of the middle section 402.

[0058] Increasing the diameter can improve structural strength. When the motor rotates at high speed, the middle section 402 bears a large centrifugal force and bending moment. Increasing the diameter can effectively improve bending and torsional stiffness. The axially outer groove 4021 on the surface of the middle section 402 is in direct contact with the external air / fluid, providing additional heat dissipation area.

[0059] The diameter of the intermediate section 402 is larger than that of the bearing position 401, which facilitates the positioning and installation of the moving iron core 101; the outer groove 4021 can serve as an airflow channel, forming a ventilation channel with the subsequent moving iron core 101, thus forming a complete internal heat dissipation channel for the rotor 1.

[0060] Preferred, such as Figure 1 , Figure 2 and Figure 3 As shown, the outer surface of the middle section 402 is covered with a moving iron core 101. The moving iron core 101 is provided with a first ventilation hole 501. Both ends of the moving iron core 101 are provided with multiple fins 8. The openings at both ends of the first ventilation hole 501 are directed to both ends of the moving iron core 101 and are located between two adjacent fins 8.

[0061] The first ventilation hole 501 creates an airflow passage inside the rotor 1, allowing heat generated by the rotor 1 and its load to be discharged to both ends through the inner hole. The fins 8 at both ends significantly increase the contact area with the air, allowing heat to be quickly dissipated after flowing out of the ventilation hole. Moreover, the fins 8 rotate with the rotor 1, thereby driving air movement and increasing airflow speed, thus improving heat dissipation efficiency. The ventilation hole openings are located between the fins 8, which facilitates the rotation of the fins 8 to drive air into the first ventilation hole 501.

[0062] Furthermore, among the fins 8 at both ends of the moving iron core 101, one end of the fin 8 can drive air into the first ventilation hole 501 when rotating, and the other end of the fin 8 can generate a suction effect on the first ventilation hole 501 when rotating. In this way, the fins 8 at both ends further accelerate the air flow speed in the first ventilation hole 501 and improve the heat dissipation efficiency of the rotor 1.

[0063] A threaded channel 1011 can be provided on the outer peripheral surface of the moving iron core 101 to increase the contact area between the moving iron core 101 and the air, thereby improving the heat dissipation effect.

[0064] Preferably, the fins 8 on both sides of the opening at one end of the first ventilation hole 501 are the first fin and the second fin, respectively, and the fins 8 on both sides of the opening at the other end of the first ventilation hole 501 are the third fin and the fourth fin, respectively. In the axial projection of the moving iron core 101, the fins 8 at both ends of the moving iron core 101 completely overlap, and the projections of the first fin, the second fin, and the third fin and the fourth fin in the axial direction overlap by at most one.

[0065] The fins at both ends 8 are completely overlapped to ensure the dynamic balance of rotor 1. The symmetrical arrangement avoids mass eccentricity, resulting in less vibration and stable operation during high-speed rotation.

[0066] The phrase "at most one of the projections of the first fin, the second fin, and the third fin and the fourth fin in the axial direction overlaps" means that "in the axial direction, one of the first fin and the third fin or the fourth fin overlaps," or "neither of the first fin nor the second fin overlaps with either the third fin or the fourth fin." Since the fins 8 at both ends of the moving iron core 101 completely overlap in the axial direction, the first ventilation hole 501 of this application is not parallel to the axis of the moving iron core 101 within the moving iron core 101. The first ventilation hole 501 can be straight or spiral. The description of the fins 8 on both sides of the openings at both ends of the first ventilation hole 501 is to restrict the direction of the first ventilation hole 501 on the iron core. This restriction extends the airflow path within the first ventilation hole 501; furthermore, the cooperation of the first fin, the second fin, the third fin, and the fourth fin allows air to enter the first ventilation hole 501 more quickly, improving the heat dissipation efficiency of the rotor core 1.

[0067] Furthermore, the direction in which air enters the first ventilation hole 501 and the direction in which air flows out of the first ventilation hole 501 are not parallel to the axis of the moving iron core 101. This allows the rotation of the fins 8 to better drive air into the first ventilation hole 501, and the air flowing out of the first ventilation hole 501 can blow the fins 8, accelerating the heat exchange between the air and the fins 8. In other words, the fins 8 of this application can not only drive airflow, but also directly absorb heat from the moving iron core 101. After the fins 8 are combined with the first ventilation hole 501, they can also accelerate the airflow through the fins 8, accelerate the heat dissipation of the fins 8, and thus accelerate the heat dissipation of the moving iron core 101.

[0068] Preferably, multiple first ventilation holes 501 are provided, with some of the first ventilation holes 501 having a forward spiral direction and some having a reverse spiral direction.

[0069] The fact that "some of the first ventilation holes 501 have a forward spiral direction and some have a reverse spiral direction" ensures that the rotor 1 can achieve the technical effects described above whether it rotates forward or reverse. Airflows with different spiral directions converge within the holes, allowing for thorough mixing of hot and cold fluids and more uniform overall heat dissipation.

[0070] Preferably, some of the first ventilation holes 501 are straight, and the straight first ventilation holes 501 are parallel to the axis of the rotating shaft 4.

[0071] As another example: straight holes allow a large amount of airflow to pass through quickly, reducing overall wind resistance; the three hole types complement each other, taking into account both flow rate and heat exchange, and the combination of the three makes the heat dissipation system achieve the best performance in three dimensions: flow rate, heat exchange efficiency, and axial force balance; adapting to different operating conditions, straight holes dominate heat dissipation at low speeds, while spiral holes have a more obvious heat exchange advantage at high speeds, making it highly adaptable to all operating conditions.

[0072] Secondly, such as Figures 6-12 As shown, the present invention also provides an electric motor, including a stator core 2 and the rotor 1, wherein the stator core 2 is provided with a second ventilation hole 502 extending along the axial direction.

[0073] The first ventilation hole 501 on rotor 1 and the second ventilation hole 502 on stator 2 work together to dissipate heat, forming a complete thermal management loop. Rotor 1 dissipates heat from both ends through the inner hole and fins 8, while stator 2 dissipates heat from the inner hole through the second ventilation hole 502. Heat is simultaneously discharged from the inside of the motor to the end covers and the outside, significantly reducing the temperature rise. The second ventilation hole 502 on stator 2 and the first ventilation hole 501 on rotor 1 are aligned (both are axial), forming a multi-dimensional heat dissipation mode with smooth airflow and no dead zones. This effectively improves motor efficiency and reliability. The reduced temperature rise means extended winding insulation life and reduced demagnetization of permanent magnets, resulting in improved overall motor efficiency and service life, achieving a dual breakthrough in motor performance improvement and cost control. The energy-saving and consumption-reducing motor technology described in this application belongs to the strategic emerging industry field.

[0074] The stator 2 core is also a stationary core 201, relative to the moving core 101 on the rotating shaft 4.

[0075] The motor also includes a housing 6, a front cover, and a rear cover, all of which have heat dissipation holes.

[0076] The rear end cover is made of cast iron and has at least one ring of exhaust holes 7, preferably two rings of exhaust holes 7, to ensure efficient heat dissipation.

[0077] Under the guiding effect of fin 8, the airflow is accelerated and discharged from the heat dissipation holes on the front and rear covers, forming the first heat dissipation path (such as...). Figure 10 (as shown) and the second heat dissipation path (as shown) Figure 11 (As shown). While effectively reducing shaft current, the motor can achieve efficient heat dissipation, and to a certain extent saves materials, reduces motor weight, and lowers costs.

[0078] Thirdly, the present invention also provides an air compressor, including the aforementioned motor.

[0079] The aforementioned motors can support air compressors to operate continuously for longer periods; due to the elimination of bearing erosion and the reduction of temperature rise, the motor failure rate decreases, and the compressor's maintenance-free cycle is extended; strong heat dissipation capacity means that the motor size can be smaller for the same power, which helps to reduce the overall weight of the compressor.

[0080] Fourthly, the present invention also provides an assembly method for rotor 1, the assembly method comprising: rotating the insulating heat-conducting sleeve 3 onto the bearing seat 401 along the rotation direction of the threaded structure 4011.

[0081] During rotation, the thread automatically aligns, and the insulating heat-conducting sleeve 3 advances at a uniform speed along the axial direction, avoiding the risk of epoxy resin breakage due to hard pressing. The rotational force ensures a more uniform interference fit; compared to axial pressing, the rotational method distributes the interference evenly along the circumference, preventing the insulating heat-conducting sleeve 3 from becoming misaligned or experiencing excessive local stress. Rotation along the thread direction tightens the fit, and utilizing the thread's self-locking property, the insulating heat-conducting sleeve 3 will not loosen on its own after assembly, requiring no additional fixing measures. The assembly process is simple, suitable for mass production, and can be completed manually without the need for specialized press-fitting equipment, reducing production costs. It is readily understood by those skilled in the art that the advantageous technical features of the above methods can be freely combined and superimposed without conflict.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A rotor used in an electric motor, characterized in that, The rotor (1) includes a rotating shaft (4) and an insulating heat-conducting sleeve (3). The rotating shaft (4) is provided with a bearing seat (401). The surface of the bearing seat (401) is provided with a raised thread structure (4011). The insulating heat-conducting sleeve (3) is interference-fitted onto the bearing seat (401).

2. The rotor according to claim 1, characterized in that, The insulating heat-conducting sleeve (3) is provided with a plurality of pore structures, which extend along the radial direction of the insulating heat-conducting sleeve (3).

3. The rotor according to claim 1, characterized in that, The inner surface of the insulating heat-conducting sleeve (3) is provided with an inner groove (301) extending along its own axial direction, and there are raised stripes (302) between two adjacent inner grooves (301). The depth of the inner groove (301) is equal to the thread height of the thread structure (4011), and the lowest point of the inner groove (301) and the highest point of the thread are located on the same cylindrical surface. or, The lowest point of the thread and the highest point of the raised stripe (302) are located on the same cylindrical surface, and the height of the raised stripe (302) is greater than the height of the thread of the thread structure (4011).

4. The rotor according to claim 1, characterized in that, The shaft (4) has a bearing seat (401) at each end, and the shaft section between the two bearing seats (401) is a middle section (402). The diameter of the middle section (402) is larger than the diameter of the bearing seat (401). The surface of the middle section (402) is provided with an outer groove (4021) that runs through the middle section (402) along the axial direction of the middle section (402).

5. The rotor according to claim 4, characterized in that, The outer surface of the middle section (402) is covered with a moving iron core (101), and a first ventilation hole (501) is provided inside the moving iron core (101). Multiple fins (8) are provided at both ends of the moving iron core (101). The openings at both ends of the first ventilation hole (501) lead to both ends of the moving iron core (101) and are located between two adjacent fins (8).

6. The rotor according to claim 5, characterized in that, The fins (8) on both sides of the opening at one end of the first ventilation hole (501) are the first fin and the second fin, respectively. The fins (8) on both sides of the opening at the other end of the first ventilation hole (501) are the third fin and the fourth fin, respectively. On the projection of the moving iron core (101) in the axial direction, the fins (8) at both ends of the moving iron core (101) completely overlap. The projections of the first fin, the second fin, and the third fin and the fourth fin in the axial direction overlap by at most one.

7. The rotor according to claim 5, characterized in that, The first ventilation hole (501) is provided in multiple ways. Some of the first ventilation holes (501) have a spiral direction that is forward, while some of the first ventilation holes (501) have a spiral direction that is reverse.

8. The rotor according to claim 7, characterized in that, Some of the first ventilation holes (501) are straight, and the straight first ventilation holes (501) are parallel to the axis of the rotating shaft (4).

9. An electric motor, characterized in that, It includes a stator (2) core and a rotor (1) as described in any one of claims 1-8, wherein the stator (2) core is provided with a second ventilation hole (502) extending in the axial direction.

10. An air compressor, characterized in that, Includes the motor as described in claim 9.

11. A method for assembling a rotor according to any one of claims 1-8, characterized in that, The assembly method includes rotating the insulating heat-conducting sleeve (3) onto the bearing position (401) along the rotation direction of the threaded structure (4011).

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