Permanent magnet synchronous motor rotor protection cover

Abstract

The utility model provides a kind of permanent magnet synchronous motor rotor protective cover, it is related to motor rotor protective cover technical field, including motor, and motor inside is equipped with rotor core, and the outer surface of rotor core is fixed with permanent magnet by interference fit, and motor middle is equipped with motor shaft;Permanent magnet is successively covered with soft magnetic filling layer, inner layer protective cover and outer layer protective cover from inside to outside periphery.The utility model is by being provided with above-mentioned structure, and it is composed of multilayer composite structure by soft magnetic filling layer, inner layer protective cover and outer layer protective cover, can reach comprehensive functional effect, by the cooperation use of the three layers structure, finally reached inner layer heat conduction, intermediate soft magnetic buffer and outer layer anti-impact multiple efficiency, overall performance and reliability of overall structure are comprehensively improved.

Description

Technical Field

[0001] This utility model relates to the technical field of motor rotor protection covers, and more specifically, to a rotor protection cover for a permanent magnet synchronous motor. Background Technology

[0002] As the core component of motor energy conversion, the design of the motor rotor directly affects the motor's efficiency, power density, and reliability. Modern rotor technology development mainly revolves around optimizing permanent magnet materials (such as neodymium iron boron magnets), structural innovation (such as segmented magnetic poles and skewed pole designs), and improving heat dissipation (such as axial ventilation holes) to meet the demands of high speed and high torque in fields such as new energy vehicles and industrial drives. Meanwhile, high-speed motor rotors need to address key technical challenges such as critical speed vibration, magnet fixation reliability, and eddy current loss control. The application of new composite materials (such as carbon fiber sheaths) further enhances the rotor's mechanical strength and thermal stability. Currently, the industry is moving towards integrated design (such as integrated motor-reducer) and intelligent control (such as precise speed regulation based on rotor position sensors).

[0003] However, existing motor rotor protective covers have the following problems during operation:

[0004] 1. Stainless steel sleeves have good electrical conductivity, which can generate significant eddy current losses in high-frequency alternating magnetic fields, leading to rotor heating and reduced motor efficiency. In addition, the sealing structure of stainless steel sleeves can hinder heat dissipation inside the rotor, and the increased temperature can affect the magnetic properties of permanent magnets.

[0005] 2. The conductivity of stainless steel sleeves can cause magnetic field distortion, which may affect the air gap magnetic flux density distribution of the motor, reduce torque output, or increase harmonic losses.

[0006] 3. In order to reduce eddy current losses, the thickness of the stainless steel sleeve will be reduced. However, reducing the thickness of the stainless steel sleeve will affect its mechanical strength. In addition, the stainless steel sleeve does not have corrosion resistance.

[0007] 4. A single stainless steel sleeve has limited functionality.

[0008] In summary, existing motor rotor protection devices suffer from significant eddy current losses leading to rotor heating and the conductivity of stainless steel sleeves causing magnetic field distortion. To address these issues, a rotor protection cover for a permanent magnet synchronous motor is disclosed. Utility Model Content

[0009] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a rotor protection cover for a permanent magnet synchronous motor. The rotor protection cover structure of this invention utilizes a multi-layered composite structure consisting of a soft magnetic filling layer, an inner protective cover, and an outer protective cover, achieving multiple benefits including inner layer heat conduction, middle soft magnetic buffering, and outer layer impact resistance.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: a rotor protective cover for a permanent magnet synchronous motor, comprising a motor, wherein a rotor core is provided inside the motor, a permanent magnet is fixed to the outer surface of the rotor core by interference fit, and a motor shaft is provided in the middle of the motor; the permanent magnet is surrounded by a soft magnetic filling layer, an inner protective cover and an outer protective cover in sequence from the inside to the outside.

[0011] Preferably, the inner protective cover is coated onto the outer surface of the permanent magnet using a hot-pressing process.

[0012] Preferably, the inner protective cover material is a thermally conductive non-magnetic alloy.

[0013] Preferably, the thermal conductivity of the inner protective cover is ≥200W / m·K.

[0014] Preferably, the soft magnetic filling layer is filled between the permanent magnet and the inner protective cover.

[0015] Preferably, the soft magnetic filling layer material is silicone composite ferrite powder.

[0016] Preferably, the thickness of the soft magnetic filling layer is 0.5mm-1mm.

[0017] Preferably, the outer protective cover covers the outside of the inner protective cover, and the outer protective cover and the inner protective cover are bonded together with epoxy resin adhesive.

[0018] Preferably, the outer protective cover material is a carbon fiber reinforced resin composite material.

[0019] Preferably, one end of the outer protective cover is provided with an overlapping post, and the end of the overlapping post away from the outer protective cover is connected to a stainless steel fixing ring, and the stainless steel fixing ring is sleeved on the motor shaft and fixed to the motor shaft by bolts.

[0020] Compared with the prior art, the beneficial effects of this utility model's technical solution are:

[0021] This invention provides a rotor protective cover for a permanent magnet synchronous motor. The inner protective cover can quickly dissipate heat from the permanent magnet, reducing its operating temperature and ensuring it remains below the demagnetization threshold. A soft magnetic filling layer fills the tiny gap between the inner protective cover and the permanent magnet, absorbing mechanical vibrations generated during high-speed rotor rotation and preventing micro-cracks in the permanent magnet, thus protecting it. It also suppresses high-frequency eddy current losses. The outer protective cover itself is high-strength and lightweight, resisting centrifugal force and preventing deformation. It also has corrosion resistance, extending the rotor core's lifespan in humid environments. The multi-layered composite structure, consisting of the soft magnetic filling layer, inner protective cover, and outer protective cover, achieves comprehensive functional effects. Through the combined use of these three layers, multiple benefits are achieved: inner layer heat conduction, middle soft magnetic buffering, and outer layer impact resistance, comprehensively improving the overall structural performance and reliability. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the overall internal front-end structure of this utility model;

[0024] Figure 3 For the present utility model Figure 2 Enlarged structural diagram at point A in the middle;

[0025] Figure 4 This is a schematic diagram of the rotor core structure of this utility model;

[0026] Figure 5 This is a schematic diagram of the overall internal rear structure of this utility model.

[0027] Among them: 10, motor; 101, motor shaft; 20, rotor core; 30, permanent magnet; 40, inner protective cover; 50, soft magnetic filling layer; 60, outer protective cover; 601, lap joint column; 602, stainless steel retaining ring. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the present invention. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0029] Example 1

[0030] like Figure 1-5 As shown, this utility model provides a rotor protective cover for a permanent magnet synchronous motor, including a motor 10. The motor 10 has a rotor core 20 inside, and a permanent magnet 30 is fixed to the outer surface of the rotor core 20 with an interference fit. The motor 10 has a motor shaft 101 in the middle. The permanent magnet 30 is surrounded by a soft magnetic filling layer 50, an inner protective cover 40, and an outer protective cover 60 from the inside to the outside. One end of the outer protective cover 60 has a connecting post 601. The end of the connecting post 601 away from the outer protective cover 60 is connected to a stainless steel fixing ring 602, and the stainless steel fixing ring 602 is sleeved on the motor shaft 101 and fixed to the motor shaft 101 by bolts.

[0031] The rotor protective cover of this utility model for a permanent magnet synchronous motor has an inner protective cover 40 that can quickly dissipate heat from the permanent magnet 30, reducing the operating temperature of the permanent magnet 30 and ensuring that the operating temperature of the permanent magnet 30 remains below the demagnetization critical point. The soft magnetic filling layer 50 fills the tiny gap between the inner protective cover 40 and the permanent magnet 30, absorbing the mechanical vibration generated during the high-speed rotation of the rotor and preventing micro-cracks in the permanent magnet 30, thus protecting the permanent magnet 30 and suppressing high-frequency eddy current losses. The outer protective cover 60 itself has high strength and lightweight characteristics, resisting centrifugal force to prevent deformation, and also has a certain degree of corrosion resistance, extending the life of the rotor core 20 in humid environments. Through the multi-layer composite structure composed of the soft magnetic filling layer 50, the inner protective cover 40, and the outer protective cover 60, comprehensive functional effects can be achieved. Through the combined use of these three layers, multiple functions are achieved, including inner heat conduction, middle soft magnetic buffering, and outer impact resistance, comprehensively improving the overall performance and reliability of the structure.

[0032] Furthermore, in another embodiment, the inner protective cover 40 is wrapped around the outer surface of the permanent magnet 30 by a hot pressing process. The material of the inner protective cover 40 is a thermally conductive non-magnetic alloy, and the thermal conductivity of the inner protective cover 40 is ≥200W / m·K.

[0033] The inner protective cover 40 can be made of copper-aluminum alloy and is wrapped around the outer surface of the permanent magnet 30 through a hot pressing process. Copper-aluminum alloy not only has excellent thermal conductivity but also non-magnetic properties. Copper-aluminum alloy can quickly conduct the temperature of the permanent magnet 30 during operation. Tests have shown that the temperature rise of the inner protective cover 40 made of copper-aluminum alloy is reduced by 15%-20%, ensuring that the operating temperature of the permanent magnet 30 is always below the demagnetization critical point. At the same time, the non-magnetic properties of the inner protective cover 40 made of copper-aluminum alloy can prevent magnetic field short circuits and ensure the air gap magnetic density.

[0034] Furthermore, in another embodiment, a soft magnetic filling layer 50 is filled between the permanent magnet 30 and the inner protective cover 40. The material of the soft magnetic filling layer 50 is silicone composite ferrite powder, and the thickness of the soft magnetic filling layer 50 is 0.5mm-1mm.

[0035] As a soft magnetic filler material, silicone composite ferrite powder can effectively absorb the impact energy generated by vibration between the permanent magnet 30 and the inner protective cover 40 when the rotor rotates at high speed, avoiding micro-cracks caused by stress concentration on the surface of the permanent magnet 30. The 0.5-1mm thickness design ensures the filling effect without excessively increasing the overall weight of the rotor, thereby reducing the impact of rotational inertia on the dynamic performance of the motor. In addition, the weight ratio of silicone to ferrite powder in the silicone composite ferrite powder is 70:30. The ferrite powder in the silicone matrix can suppress high-frequency eddy current loss. According to the test, the motor efficiency is improved by 1%-2%.

[0036] Furthermore, in another embodiment, the outer protective cover 60 covers the outside of the inner protective cover 40, and the outer protective cover 60 and the inner protective cover 40 are bonded together by epoxy resin adhesive. The material of the outer protective cover 60 is carbon fiber reinforced resin composite material.

[0037] The epoxy resin adhesive bonding method ensures a tight fit between the outer protective cover 60 and the inner protective cover 40, avoiding vibration noise caused by gaps during high-speed rotation. Simultaneously, the epoxy resin adhesive also acts as insulation, preventing the formation of a conductive path between the outer and inner protective covers 60, thus preventing stray currents. Furthermore, the outer protective cover 60 uses carbon fiber reinforced resin as its material. This material has high strength and low density, with a tensile strength exceeding 800 MPa and a density of less than 2.0 g / cm³. The outer protective cover 60 can resist centrifugal force to prevent deformation. Tests have shown that the carbon fiber reinforced resin outer protective cover 60 can withstand centrifugal force >20,000 rpm without risk of breakage. Additionally, the outer protective cover 60 has high corrosion resistance, protecting the rotor core 20 and preventing it from getting damp to a certain extent.

[0038] Working principle: When the motor 10 is running, the rotor core 20 drives the permanent magnet 30 to rotate at high speed with the motor shaft 101. The magnetic field generated by the permanent magnet 30 interacts with the stator winding through the air gap to realize energy conversion. During this process, the inner protective cover 40 is tightly attached to the outer surface of the permanent magnet 30 to quickly dissipate the heat generated by the permanent magnet 30 due to eddy current and hysteresis losses. The copper-aluminum alloy material used has a thermal conductivity of ≥200W / m·K, which can effectively control the working temperature of the permanent magnet 30 and avoid the risk of demagnetization due to high temperature.

[0039] The soft magnetic filling layer 50 is filled between the permanent magnet 30 and the inner protective cover 40. The 0.5-1mm thick silicone composite ferrite powder material can absorb the impact energy generated by rotational vibration, protect the permanent magnet 30 from mechanical damage, and suppress high-frequency eddy currents and reduce additional losses through the soft magnetic properties of ferrite powder.

[0040] The outer protective cover 60 is firmly bonded to the inner protective cover 40 with epoxy resin adhesive. The carbon fiber reinforced resin material, with its high strength (tensile strength ≥800MPa) and lightweight (density <2.0g / cm³) characteristics, provides reliable mechanical protection for the overall structure, resists the centrifugal force generated by high-speed rotation, and prevents deformation of the inner structure. At the same time, its corrosion resistance can slow down the aging rate of the rotor core 20 in a humid environment. The synergistic effect of each layer of structure improves the rotor's anti-demagnetization ability and operational reliability from multiple dimensions such as thermal protection, mechanical buffering, electromagnetic optimization and structural reinforcement.

[0041] Unless otherwise specified, in this utility model, terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe orientation or positional relationships in this utility model are for illustrative purposes only and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the accompanying drawings and according to the specific circumstances.

[0042] Unless otherwise expressly specified and limited, the terms "set up," "connected," and "linked" in this utility model should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0043] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although this utility model has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A rotor protective cover for a permanent magnet synchronous motor, comprising a motor (10), characterized in that: The motor (10) has a rotor core (20) inside, and a permanent magnet (30) is fixed to the outer surface of the rotor core (20) with an interference fit. The motor (10) has a motor shaft (101) in the middle. The permanent magnet (30) is surrounded by a soft magnetic filling layer (50), an inner protective cover (40) and an outer protective cover (60) from the inside out.

2. The rotor protective cover for a permanent magnet synchronous motor according to claim 1, characterized in that: The inner protective cover (40) is wrapped around the outer surface of the permanent magnet (30) by a hot pressing process.

3. The rotor protective cover for a permanent magnet synchronous motor according to claim 1, characterized in that: The inner protective cover (40) is made of a thermally conductive non-magnetic alloy.

4. The rotor protective cover for a permanent magnet synchronous motor according to claim 3, characterized in that: The thermal conductivity of the inner protective cover (40) is ≥200W / m·K.

5. The rotor protective cover for a permanent magnet synchronous motor according to claim 1, characterized in that: The soft magnetic filling layer (50) is filled between the permanent magnet (30) and the inner protective cover (40).

6. The rotor protective cover for a permanent magnet synchronous motor according to claim 1, characterized in that: The soft magnetic filling layer (50) is made of silicone composite ferrite powder.

7. The rotor protective cover for a permanent magnet synchronous motor according to claim 1, characterized in that: The thickness of the soft magnetic filler layer (50) is 0.5mm-1mm.

8. The rotor protective cover for a permanent magnet synchronous motor according to claim 1, characterized in that: The outer protective cover (60) covers the outside of the inner protective cover (40), and the outer protective cover (60) and the inner protective cover (40) are bonded together with epoxy resin adhesive.

9. The rotor protective cover for a permanent magnet synchronous motor according to claim 8, characterized in that: The outer protective cover (60) is made of carbon fiber reinforced resin composite material.

10. The rotor protective cover for a permanent magnet synchronous motor according to claim 1, characterized in that: One end of the outer protective cover (60) is provided with an overlapping post (601). The end of the overlapping post (601) away from the outer protective cover (60) is connected to a stainless steel fixing ring (602). The stainless steel fixing ring (602) is sleeved on the motor shaft (101) and fixed to the motor shaft (101) by bolts.

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