A high-speed induction motor rotor structure with radially layered electromagnetic parameter gradient

Abstract

The application relates to the technical field of induction motor rotors, in particular to a high-speed induction motor rotor structure with radially layered electromagnetic parameter gradual change, which comprises a rotating shaft, a solid rotor in the shape of a sleeve coaxially sleeved and fixed on the rotating shaft, a gradual change layer which is a radially layered assembly composed of a plurality of material layers with different electromagnetic parameters and stacked in sequence from the inside to the outside along the radial direction of the solid rotor, the gradual change layer is in the shape of a sleeve and tightly covers the outer circumferential surface of the solid rotor, an end ring fixedly installed on the axial two ends of the solid rotor and electrically connected with the end part of the gradual change layer to form a closed conductive loop, wherein the electromagnetic parameters of the gradual change layer gradually change from the inside to the outside along the radial direction, so that the electric conductivity gradually increases from the inside to the outside, and the magnetic conductivity gradually decreases from the inside to the outside. Through the radially layered electromagnetic parameter gradual change and collaborative adaptation, the application realizes the accurate collaborative control of rotor eddy current loss and resistance loss, minimizes the total loss and improves the energy conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of induction motor rotor technology, and in particular to a high-speed induction motor rotor structure with radially layered electromagnetic parameters. Background Technology

[0002] High-speed induction motors, with their advantages of high power density and fast dynamic response, are widely used in aerospace, high-speed grinding machines, energy storage flywheels, and other fields. As its core component, the rotor must simultaneously withstand enormous centrifugal force, electromagnetic force, and thermal stress during high-speed operation, placing stringent requirements on its mechanical strength and electromagnetic performance. Solid rotors, due to their one-piece molded structure, offer high mechanical strength and excellent dynamic balance, and have become the mainstream rotor type for high-speed induction motors.

[0003] However, existing solid rotors are mostly made of a single material, presenting a dual contradiction: they cannot simultaneously achieve low eddy current losses and high electromagnetic torque. Specifically: while using high-permeability materials can increase magnetic flux density and electromagnetic torque, the high conductivity leads to significant eddy current losses at high speeds; conversely, using high-conductivity materials can reduce resistive losses, but the low permeability results in insufficient torque output. Crucially, if only high-conductivity materials are used on the outer layer of the rotor, the lack of a matching design with low permeability causes surface eddy current losses to surge due to the combined effect of conductivity and magnetic flux density, severely limiting further improvements in motor efficiency and power density. Furthermore, some existing layered rotor structures employ axial layering or simple material stacking, resulting in abrupt changes in electromagnetic parameters. This easily leads to interfacial electromagnetic shocks and additional losses, and the interlayer bonding is weak, posing a risk of delamination under high-speed conditions. Therefore, how to achieve a synergistic adaptation of permeability and conductivity through spatially gradual configuration of electromagnetic parameters, simultaneously suppressing eddy current and resistive losses from a mechanistic perspective, while also considering rotor mechanical strength and high-speed stability, has become a technical problem to be solved in this field. Summary of the Invention

[0004] In view of at least one of the above-mentioned technical problems, the present invention provides a high-speed induction motor rotor structure with radially layered electromagnetic parameters, which solves the problems mentioned in the background art.

[0005] This application provides a high-speed induction motor rotor structure with radially layered electromagnetic parameters, comprising: Shaft; A solid rotor, in the shape of a sleeve, is coaxially fitted and fixed to the rotating shaft; The gradient layer is a radially layered assembly consisting of several layers of materials with different electromagnetic parameters stacked sequentially from the inside to the outside along the radial direction of the solid rotor. The gradient layer is cylindrical in shape and tightly covers the outer circumference of the solid rotor. The end rings are fixedly installed at both ends of the solid rotor and electrically connected to the ends of the gradient layer to form a closed conductive circuit. The electromagnetic parameters of the gradient layer gradually change radially from the inside to the outside, so that its conductivity increases from the inside to the outside and its magnetic permeability decreases from the inside to the outside.

[0006] Preferably, the gradient layer is configured to achieve coordinated control of rotor eddy current loss and resistance loss through the coordinated adaptation of magnetic permeability and electrical conductivity. The inner layer has a higher magnetic permeability and a lower electrical conductivity than the outer layer. The inner layer is configured to suppress inner layer eddy current loss, and the outer layer is configured to suppress outer layer eddy current loss while reducing resistance loss.

[0007] Preferably, the solid rotor is a one-piece molded low-carbon steel component, the inner wall of which is interference-fitted with the shaft, and the mating surface is provided with anti-slip texture; the axial ends of the solid rotor are provided with stepped surfaces for positioning and installing the end rings.

[0008] Preferably, the gradient layer comprises at least a lower tooth layer, an upper tooth layer, and a sheath layer stacked sequentially from the inside out; The lower tooth layer has the highest magnetic permeability and the lowest electrical conductivity among all layers of the gradient layer; The sheath layer has the lowest magnetic permeability and the highest electrical conductivity among all layers of the gradient layer; The magnetic permeability and electrical conductivity of the upper tooth layer are both between those of the lower tooth layer and the sheath layer.

[0009] Preferably, the sheath layer is made of copper alloy or aluminum alloy, and the lower tooth layer is made of high magnetic permeability low carbon steel.

[0010] Preferably, the total thickness of the gradient layer is 10%-30% of the outer diameter of the solid rotor; wherein, the thickness of the lower tooth layer accounts for 40%-60% of the total thickness, the thickness of the upper tooth layer accounts for 20%-30% of the total thickness, and the thickness of the sheath layer accounts for 10%-30% of the total thickness.

[0011] Preferably, the end ring is made of the same conductive material as the sheath layer and is fixed and electrically connected to at least the end of the sheath layer of the gradient layer by welding or die casting.

[0012] Preferably, the adjacent material layers of the gradient layer are fixed by metallurgical bonding or adhesive bonding processes to achieve a seamless and tight bond.

[0013] Preferably, the upper tooth layer is a composite material layer of magnetic and conductive materials, and the content of the magnetic material gradually decreases and the content of the conductive material gradually increases from the inside to the outside along the radial direction to achieve a continuous and gradual change in electromagnetic parameters.

[0014] Preferably, the outer surface of the gradient layer is further provided with a high-temperature resistant insulating protective layer, and / or the inner wall of the solid rotor is provided with a plurality of axial heat dissipation grooves.

[0015] The present invention has the following technical effects: (1) This application achieves precise coordinated control of rotor eddy current loss and resistance loss through radial layering of electromagnetic parameters and coordinated adaptation. The present invention sets the conductivity of the gradient layer to increase and the magnetic permeability to decrease from the inside to the outside in the radial direction. This solves the contradiction that a single material or parameter abrupt structure cannot take into account the control of the two types of losses. The high magnetic permeability and low conductivity configuration of the inner layer can efficiently guide magnetic flux and improve torque while suppressing eddy current loss in the high magnetic flux density area. The low magnetic permeability and high conductivity configuration of the outer layer can reduce the resistance loss of the induced current loop while using the low magnetic permeability to weaken the surface magnetic flux density and offset the negative impact of high conductivity on eddy current loss. This overcomes the key defect that the high conductivity outer layer alone causes a surge in surface eddy current loss. The intermediate transition layer ensures smooth parameter transition through continuous or stepwise gradual change of magnetic and conductive material content, avoiding additional losses caused by interface electromagnetic abrupt changes. The three layers work together to minimize the total loss and improve the energy conversion efficiency.

[0016] (2) By integrating the sleeve-type gradient layer with the solid rotor, the mechanical strength, high-speed stability and electromagnetic performance are taken into account. The present invention uses the sleeve-type solid rotor core as the base. While ensuring the magnetic conductivity and basic structural strength, it reduces weight, reduces centrifugal force, and improves high-speed dynamic balance accuracy. The gradient layer is tightly wrapped around the outer circumference of the core. The layers are seamlessly connected by metallurgical bonding or high-temperature bonding, eliminating the risk of high-speed delamination. The end ring and the outer layer of the gradient layer are electrically connected by the same material, ensuring the electrical reliability and structural integrity of the closed conductive circuit. Therefore, the present invention does not require modification of the motor stator. It can achieve high strength support, low loss electromagnetic conversion and high heat diffusion capability in a single rotor structure, which is suitable for high speed and high power density operation requirements. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a radial sectional view of the present invention.

[0019] Figure 2 It is in this invention Figure 1 Schematic diagram of the cross-sectional structure at point AA.

[0020] Figure 3 This is a schematic diagram of the gradient layer structure in this invention.

[0021] Figure label: 1. Shaft; 2. Solid rotor; 3. Cage bars; 4. End ring; 5. Gradient layer; 6. Lower tooth layer; 7. Upper tooth layer; 8. Sheath layer. Detailed Implementation

[0022] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0023] Example 1

[0024] This embodiment provides a high-speed induction motor rotor structure with radially layered electromagnetic parameter gradients. This structure achieves coordinated control of eddy current losses and resistive losses through radially varying electromagnetic parameters, thus balancing mechanical strength and electromagnetic performance at high speeds. This embodiment is particularly suitable for high-speed induction motors with a speed of 15000 r / min.

[0025] like Figure 1 and Figure 2 As shown, the rotor structure mainly consists of four parts: shaft 1, solid rotor 2, gradient layer 5, and end ring 4.

[0026] The rotating shaft 1 is used to transmit torque and needs to withstand the enormous centrifugal force generated by high-speed rotation. In this embodiment, the rotating shaft 1 is made of high-strength alloy steel such as 40Cr or 42CrMo that has undergone quenching and tempering treatment, with a hardness reaching HRC30-HRC35, and has good comprehensive mechanical properties. The diameter and length of the rotating shaft 1 are determined according to the motor power; in this embodiment, the diameter is approximately 50mm and the length is approximately 200mm. To enhance the reliability of its connection with the solid rotor 2 and prevent relative rotation during high-speed rotation, the mating surfaces of the rotating shaft 1 and the solid rotor 2 are provided with spiral or mesh-like anti-slip patterns.

[0027] The solid rotor 2 is the structural base and magnetic circuit body of the entire rotor, and is in the shape of a hollow sleeve, coaxially fitted and fixed to the rotating shaft 1. In this embodiment, the solid rotor 2 is integrally formed from Q235 low-carbon steel with excellent magnetic permeability, which ensures the permeability required as part of the magnetic circuit and provides sufficient structural strength. Its inner wall and the rotating shaft 1 are interference-fitted (e.g., H7 / k6 tolerance grade) to ensure a tight fit without relative looseness. The outer diameter of the solid rotor 2 is approximately 100mm, and its length is 150mm. Each of the two axial ends of the solid rotor 2 is provided with an annular stepped surface for precise positioning and bearing of the end ring 4. Compared with the traditional solid rotor, the sleeve-shaped structure effectively reduces weight while ensuring mechanical strength, facilitating the arrangement of the gradient layer 5.

[0028] As a further optimization, several axially extending heat dissipation grooves can be evenly formed along the circumference of the inner wall of the solid rotor 2. In this embodiment, a total of 4 heat dissipation grooves with a U-shaped cross-section, approximately 3 mm wide and 2 mm deep are provided to increase the heat dissipation area, accelerate the dissipation of internal heat, and reduce the rotor temperature rise.

[0029] The gradient layer 5 is the core innovative component of this invention. It is a sleeve-type radially layered assembly formed by stacking layers from the inside to the outside along the radial direction of the solid rotor 2, tightly covering the outer circumferential surface of the solid rotor 2. The electromagnetic parameters of the gradient layer 5 gradually change radially from the inside to the outside, specifically: the conductivity increases from the inside to the outside, and the permeability decreases from the inside to the outside. This unique parameter configuration is to achieve synergistic control of losses: the higher permeability and lower conductivity of the inner layer are configured to suppress inner layer eddy current losses while efficiently guiding magnetic flux; the lower permeability and higher conductivity of the outer layer are configured to reduce resistive losses while weakening magnetic flux density to suppress outer layer eddy current losses.

[0030] Specifically, in this embodiment, such as Figure 3 As shown, the gradient layer 5 comprises, from the inside out, a lower tooth layer 6, an upper tooth layer 7, and a sheath layer 8. The total thickness of the gradient layer 5 is set to approximately 20 mm, which is approximately 20% of the outer diameter of the solid rotor 2.

[0031] The lower tooth layer 6 is disposed in close contact with the solid rotor 2, and it has the highest magnetic permeability and the lowest electrical conductivity among all layers of the gradient layer 5. In this embodiment, the lower tooth layer 6 is made of high-permeability low-carbon steel, with a thickness of approximately 10 mm, occupying 50% of the total thickness of the gradient layer 5. Its magnetic permeability (μ) ≥ 1500 and electrical conductivity (σ) ≤ 5 × 10⁻⁶. 6 S / m. This layer, as the main region carrying magnetic flux, has high permeability that can improve the magnetic coupling efficiency and electromagnetic torque of the motor, while its low conductivity effectively suppresses eddy current losses in this high flux density region.

[0032] The sheath layer 8 is located at the outermost layer of the gradient layer 5, and it has the lowest magnetic permeability and the highest electrical conductivity among all layers of the gradient layer 5. In this embodiment, the sheath layer 8 is made of highly conductive T2 copper or aluminum alloy, with a thickness of approximately 4 mm, occupying 20% ​​of the total thickness of the gradient layer 5. Its magnetic permeability (μ) ≤ 500 and electrical conductivity (σ) ≥ 5.8 × 10⁻⁶. 7 S / m. This layer, serving as the primary channel for the generation and flow of induced current, significantly reduces the resistance loss of the circuit due to its high conductivity. Simultaneously, its low magnetic permeability actively weakens the surface magnetic flux density, mechanistically suppressing the surge in surface eddy current losses caused by high conductivity. Testing has verified that, compared to a single high-conductivity outer layer structure, the eddy current loss of the sheath layer 8 in this embodiment can be reduced by more than 35%. Furthermore, the excellent thermal conductivity of this layer also makes it a highly efficient heat dissipation surface.

[0033] In one embodiment, to further enhance the conductivity and mechanical strength of the sheath layer 8, multiple axially extending cage bars 3 are provided within the sheath layer 8. The cage bars 3 are evenly spaced along the circumference of the sheath layer 8, and their number is determined according to the number of motor poles and power rating, and can be up to eight. The cage bars 3 are made of a high-conductivity, high-strength conductive material, preferably the same as or with higher conductivity than the sheath layer 8, such as T2 copper, beryllium copper alloy, or high-strength copper alloy. The cross-sectional shape of the cage bars 3 can be circular, rectangular, or trapezoidal, and its radial height does not exceed the thickness of the sheath layer 8, ensuring that the sheath layer 8 still has continuous material coverage on the radially outer side of the cage bars 3, maintaining the integrity of the outer surface of the gradient layer 5 and its low magnetic permeability characteristics. The two ends of the cage bars 3 extend to the axial end face of the gradient layer 5 and are electrically connected to the corresponding end rings 4 through welding or die-casting. Thus, the cage bars 3 and the end rings 4 together form a low-resistance closed conductive loop, undertaking the main function of conducting induced current. The high strength of the cage bar 3 further enhances the structural integrity of the sheath layer 8 and even the entire gradient layer 5 under high-speed rotation. With the cage bar 3 in place, the sheath layer 8 as a whole still maintains its low magnetic permeability and high electrical conductivity parameters. The cage bar 3, as a further concentration area of ​​electrical conductivity within the sheath layer 8, strengthens the directional conduction capability of the induced current and further reduces the equivalent resistance of the circuit.

[0034] The upper toothed layer 7 is disposed between the lower toothed layer 6 and the sheath layer 8, and its magnetic permeability and electrical conductivity values ​​are both between those of the lower toothed layer 6 and the sheath layer 8. In this embodiment, to ensure a smooth transition of electromagnetic parameters and avoid electromagnetic shocks and additional interface losses caused by abrupt parameter changes, the upper toothed layer 7 employs a mixed composite material layer with a gradient change in material composition. Internally, from the inside to the outside radially, the content of magnetically conductive material (such as low-carbon steel powder) gradually decreases, while the content of electrically conductive material (such as copper powder or aluminum powder) gradually increases. Specifically, the content of magnetically conductive material decreases from approximately 80% to approximately 20%, while the content of electrically conductive material increases accordingly. The thickness of the upper toothed layer 7 is approximately 6 mm, occupying 30% of the total thickness of the gradient layer 5. This continuous change in microstructure achieves a "gradient" effect on a macroscopic scale, with continuously decreasing magnetic permeability and continuously increasing electrical conductivity, ensuring efficient and smooth conduction and conversion of magnetic flux and induced current between the inner and outer layers. It is understood that in other alternative embodiments, this gradient can also be achieved through multiple sublayers with varying proportions in a stepped manner.

[0035] To ensure the structural integrity of the rotor under high-speed centrifugal force, the adjacent layers of the gradient layer 5, namely the lower tooth layer 6 and the upper tooth layer 7, and the upper tooth layer 7 and the sheath layer 8, are fixed using metallurgical bonding processes (such as hot isostatic pressing or diffusion welding). Of course, depending on the actual situation, high-strength, high-temperature resistant bonding processes can also be used to replace metallurgical bonding.

[0036] As an additional layer of protection, a high-temperature resistant insulating protective layer made of polyimide or polyetheretherketone can also be provided on the outer surface of the gradient layer 5, i.e., the outer circumferential surface of the sheath layer 8. In this embodiment, the insulating protective layer is about 0.5 mm thick and can be formed by spraying or impregnation processes to prevent short circuits between the rotor and stator.

[0037] The end ring 4 consists of two perfectly symmetrical annular components, one on the left and one on the right, which are fixedly mounted on the stepped surfaces at both ends of the solid rotor 2. The key function of the end ring 4 is to form a complete closed conductive circuit with the gradient layer 5. Therefore, the end ring 4 is preferably made of the same conductive material as the sheath layer 8 (such as T2 copper), with its inner diameter matching the stepped surface and its outer diameter flush with the outer circumference of the sheath layer 8 to maintain the rotor's dynamic balance. The end ring 4 and at least the ends of the sheath layer 8 of the gradient layer 5 are reliably electrically connected and mechanically fixed using welding processes such as argon arc welding, laser welding, or integral die casting.

[0038] The collaborative working process in this embodiment is as follows: During motor operation, the rotating magnetic field generated by the stator windings cuts the rotor. The lower tooth layer 6 in the gradient layer 5, with its high permeability, efficiently absorbs and guides magnetic flux from the air gap, generating a powerful electromagnetic torque, while its low conductivity effectively suppresses inner layer eddy current losses. Simultaneously, current is induced in the sheath layer 8; its high conductivity allows the induced current to flow with minimal resistance loss, forming a closed loop through the end ring 4. Crucially, the low permeability of the sheath layer 8 actively reduces the magnetic flux density in its region, successfully suppressing the potential surge in surface eddy current losses due to high conductivity. The upper tooth layer 7, through its gradient electromagnetic parameters, ensures a smooth and efficient transition of magnetic flux and current between the "high permeability-low conductivity" lower tooth layer 6 and the "low permeability-high conductivity" sheath layer 8, avoiding electromagnetic abrupt changes and energy losses at the interface. Under this synergistic control of permeability and conductivity, both iron and copper losses of the rotor are precisely suppressed, minimizing total losses and increasing power density.

[0039] Structurally, the sleeve-shaped solid rotor 2 and the high-strength shaft 1 form a robust mechanical body, while the integrated, tightly fitted gradient layer 5 and end ring 4 jointly bear the centrifugal force and thermal stress brought about by ultra-high-speed rotation, ensuring the reliability and stability of long-term operation. It is understood that the scope of protection of this invention is not limited to the specific embodiments described above. For example, the number of gradient layers 5 can be adjusted to two or more layers as needed; the thickness ratio of each layer, the specific material grade, etc., can all be flexibly adjusted and combined within the scope defined by this invention.

[0040] Example 2

[0041] This embodiment has a structure that is basically the same as that of Embodiment 1, except for the number of gradient layers 5.

[0042] In this embodiment, the gradient layer 5 consists of only two layers from the inside out: the lower toothed layer 6 and the sheath layer 8, omitting the upper toothed layer 7. The lower toothed layer 6 is directly adjacent to and bonded to the sheath layer 8.

[0043] To achieve a gradual transition in electromagnetic parameters, the lower tooth layer 6 and the sheath layer 8 are fixed together using metallurgical bonding or high-temperature adhesive bonding processes, forming a tight metallurgical or adhesive interface. Although the number of layers is reduced, the lower tooth layer 6 and the sheath layer 8 still maintain the parameter characteristics of high permeability and low electrical conductivity, and low permeability and high electrical conductivity, respectively, so that from the inside of the rotor to the outer surface, there is still an overall gradual trend of increasing electrical conductivity and decreasing permeability.

[0044] The advantages of this embodiment are its simpler structure and lower manufacturing cost. It is suitable for cost-sensitive applications with relatively low rotational speeds (e.g., 10,000-12,000 r / min). However, compared to the three-layer structure, the parameter range between the two layers is larger, and the transition of electromagnetic parameters at the interface is not as smooth as in the three-layer structure.

[0045] The remaining structure and working process of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0046] Example 3

[0047] This embodiment has a structure that is basically the same as that of Embodiment 1. The difference lies in the bonding process between the layers of the gradient layer 5 and the treatment of the interlayer interfaces.

[0048] In this embodiment, the adjacent layers of the gradient layer 5, namely the lower toothed layer 6 and the upper toothed layer 7, and the upper toothed layer 7 and the sheath layer 8, are not fixed by metallurgical bonding, but by high-strength, high-temperature resistant adhesive bonding. Specifically, the adhesive used is a high-temperature resistant epoxy resin or an inorganic silicate adhesive with a temperature resistance rating of H-class 180°C or higher.

[0049] To ensure reliable bonding, the surfaces of each layer to be bonded are pre-treated with sandblasting or chemical etching to increase surface roughness. After bonding, the layers are cured under high temperature and pressure. The thickness of the bonding layer is controlled between 0.05mm and 0.1mm to ensure bonding strength without significantly affecting the transition of electromagnetic parameters between layers.

[0050] Compared to metallurgical bonding, bonding processes require lower equipment investment, operate at lower temperatures, and have less thermal impact on material properties, making them suitable for small to medium batch production.

[0051] The remaining structure and working process of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0052] In summary, the radially layered electromagnetic parameter gradient high-speed induction motor rotor structure provided by this invention, through its radially layered electromagnetic parameter gradient design, especially the three-layer synergistic gradient layer 5 structure, solves the contradiction between electromagnetic performance and loss control that a single-material rotor cannot simultaneously achieve. At the same time, its sleeve-type integral structure ensures high-speed mechanical stability.

[0053] The above are merely preferred embodiments of this application and do not constitute any limitation on this application. Any person skilled in the art can make many possible variations and modifications to the technical solution of this application, or modify it into equivalent embodiments, without departing from the scope of the technical solution of this application. Therefore, all equivalent changes made based on the shape, structure, and principle of this application without departing from the content of the technical solution of this application should be covered within the protection scope of this application.

Claims

1. A high-speed induction motor rotor structure with radially layered electromagnetic parameters, characterized in that, include: Rotating shaft (1); A solid rotor (2) is sleeve-shaped and coaxially mounted and fixed on the rotating shaft (1); The gradient layer (5) is a radially layered assembly consisting of several layers of materials with different electromagnetic parameters stacked sequentially from the inside to the outside along the radial direction of the solid rotor (2). The gradient layer (5) is cylindrical in shape and tightly covers the outer circumference of the solid rotor (2). The end ring (4) is fixedly installed at both ends of the solid rotor (2) and electrically connected to the end of the gradient layer (5) to form a closed conductive circuit. The electromagnetic parameters of the gradient layer (5) gradually change radially from the inside to the outside, so that its conductivity increases from the inside to the outside and its magnetic permeability decreases from the inside to the outside.

2. The high-speed induction motor rotor structure with radially layered electromagnetic parameters according to claim 1, characterized in that: The gradient layer (5) is configured to achieve coordinated control of rotor eddy current loss and resistance loss through the coordinated adaptation of magnetic permeability and electrical conductivity. The magnetic permeability of the inner layer is higher than that of the outer layer and the electrical conductivity is lower than that of the outer layer. The inner layer is configured to suppress inner layer eddy current loss, and the outer layer is configured to suppress outer layer eddy current loss while reducing resistance loss.

3. The high-speed induction motor rotor structure with radially layered electromagnetic parameters according to claim 1, characterized in that: The solid rotor (2) is an integrally formed low-carbon steel component. Its inner wall is interference-fitted with the rotating shaft (1), and the mating surface is provided with anti-slip texture. The solid rotor (2) has stepped surfaces at both ends of its axial direction for positioning and installing the end ring (4).

4. The high-speed induction motor rotor structure with radially layered electromagnetic parameters according to claim 1, characterized in that: The gradient layer (5) includes, from the inside out, at least a lower toothed layer (6), an upper toothed layer (7), and a sheath layer (8) stacked sequentially. The lower tooth layer (6) has the highest magnetic permeability and the lowest electrical conductivity among all layers of the gradient layer (5); The sheath layer (8) has the lowest magnetic permeability and the highest electrical conductivity among all layers of the gradient layer (5); The magnetic permeability and electrical conductivity of the upper tooth layer (7) are both between those of the lower tooth layer (6) and the sheath layer (8).

5. The high-speed induction motor rotor structure with radially layered electromagnetic parameters according to claim 4, characterized in that: The sheath layer (8) is made of copper alloy or aluminum alloy, and the lower tooth layer (6) is made of high magnetic permeability low carbon steel.

6. The high-speed induction motor rotor structure with radially layered electromagnetic parameters according to claim 4, characterized in that: The total thickness of the gradient layer (5) is 10%-30% of the outer diameter of the solid rotor (2); wherein, the thickness of the lower tooth layer (6) accounts for 40%-60% of the total thickness, the thickness of the upper tooth layer (7) accounts for 20%-30% of the total thickness, and the thickness of the sheath layer (8) accounts for 10%-30% of the total thickness.

7. The high-speed induction motor rotor structure with radially layered electromagnetic parameters according to claim 4, characterized in that: The end ring (4) is made of the same conductive material as the sheath layer (8) and is fixed and electrically connected to at least the end of the sheath layer (8) of the gradient layer (5) by welding or die casting.

8. The high-speed induction motor rotor structure with radially layered electromagnetic parameters according to claim 1, characterized in that: The adjacent material layers of the gradient layer (5) are fixed by metallurgical bonding or adhesive bonding processes to achieve a seamless and tight bond.

9. The high-speed induction motor rotor structure with radially layered electromagnetic parameters according to claim 4, characterized in that: The upper tooth layer (7) is a composite material layer of magnetic and conductive materials. In its interior, the content of magnetic material gradually decreases from the inside to the outside along the radial direction, while the content of conductive material gradually increases, so as to achieve a continuous and gradual change in electromagnetic parameters.

10. The high-speed induction motor rotor structure with radially layered electromagnetic parameters according to claim 1, characterized in that: The outer surface of the gradient layer (5) is also provided with a high-temperature resistant insulating protective layer, and / or the inner wall of the solid rotor (2) is provided with a number of axial heat dissipation grooves.

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