High-speed low-noise motor rotor structure, high-speed motor and design method

Abstract

The application provides a high-speed low-noise motor rotor structure, a high-speed motor and a design method. The structure comprises a rotor body, the rotor body is divided into at least two rotor segments in the axial direction, and a spacing area is formed between two adjacent rotor segments in the axial direction; at least one potting segment, each potting segment is formed by potting material filled in each spacing area; wherein the density of the potting material is less than the average density of the rotor segment, and the potting material is composed of a non-magnetic material. Through the rotor structure provided by the application, the mass distribution and the inertia moment change law of the rotor can be optimized without changing the overall shaft structure of the rotor system, so as to improve the critical speed and improve the vibration characteristics.

Description

Technical Field

[0001] This application relates to the field of high-speed motor rotor structure technology, and in particular to a high-speed, low-noise motor rotor structure, a high-speed motor, and a design method. Background Technology

[0002] As a core power device in modern industrial systems, electric motors are widely used in aerospace, rail transportation, precision machining, new energy equipment, and high-speed compressors. With the development of high-end equipment towards higher power density, higher speed, and higher reliability, high-speed motors are gradually becoming a key development direction. Compared to traditional low-speed motors, high-speed motors can output higher power in a smaller size and lighter weight. However, at the same time, they face more stringent requirements in terms of structural strength, dynamic characteristics, and operational stability. In the motor structure, the rotor, as the core component directly involved in energy conversion and transmission, directly determines the motor's output capacity and operational reliability. Especially under high-speed operating conditions, the rotor not only bears significant centrifugal force but is also subjected to the combined effects of unbalanced forces, magnetic pull, and aerodynamic forces. Therefore, its structural design must not only meet strength requirements but also ensure reliable stability.

[0003] The critical speed of the rotor is a core indicator for evaluating the structural stability of the rotor. In high-speed motor design, the rotor's operating speed is typically required to avoid or be far from the critical speed range to ensure the safety and stability of the equipment. Therefore, increasing the rotor's critical speed while ensuring structural strength and dynamic characteristics has become one of the key technical issues in high-speed motor design.

[0004] Traditional high-speed motor rotors typically employ an integral structural design, such as placing a single ring-shaped permanent magnet around the rotor core to ensure the integrity of the mechanical structure. However, the integral ring-shaped magnet structure has the following drawbacks during high-speed rotation: Firstly, the rotor's mass distribution is concentrated and continuous, resulting in significant centrifugal stress during high-speed operation, which can easily lead to dynamic imbalance due to localized mass eccentricity or uneven distribution. Secondly, the rotor shaft system has low mode shape freedom, and the rotor's vibration characteristics are fixed, limiting the improvement of its critical speed. Summary of the Invention

[0005] To address the aforementioned problems, one objective of this application is to provide a high-speed, low-noise motor rotor structure to solve the technical problem that the critical speed of traditional rotor structures is difficult to further increase. A second objective is to provide a high-speed motor, and a third objective is to provide a design method for a high-speed, low-noise motor rotor structure.

[0006] Firstly, this application provides a high-speed, low-noise motor rotor structure, the technical solution of which is: A high-speed, low-noise motor rotor structure, comprising: The rotor body is divided into at least two rotor segments along the axial direction, and an interval region is formed between two axially adjacent rotor segments. At least one potting section, each of the potting sections being formed by potting material filling each of the interval regions; wherein the density of the potting material is less than the average density of the rotor segments, and is composed of a non-magnetic material.

[0007] As one of the preferred options, the potting material includes at least one of epoxy resin, high-performance composite material and ceramic matrix material.

[0008] As one of the preferred embodiments, the rotor body includes a rotor core and a plurality of segmented magnets, the plurality of segmented magnets being axially spaced and sleeved on the rotor core, with the interval region formed between two adjacent segmented magnets.

[0009] As a preferred embodiment, the axial lengths of the multiple segmented magnets are the same; and / or, The axial distances of the multiple interval regions are non-uniformly distributed to achieve mass compensation for the rotor shaft system vibration mode.

[0010] As one of the preferred solutions, the interval region isolates two adjacent segmented magnets.

[0011] Secondly, this application also provides a high-speed motor, including the high-speed, low-noise motor rotor structure provided in the first aspect of this application.

[0012] Thirdly, this application also provides a design method for a high-speed, low-noise motor rotor structure, used to design the high-speed, low-noise motor rotor structure provided in the first aspect of this application, the method comprising: A dynamic model of the rotor body of the rotor shaft system is established, wherein the rotor body includes at least two rotor segments and an interval region located between two adjacent rotor segments; The material properties of multiple rotor segments and multiple interval regions are set, the rotor segments are simulated as high-density mass units, and the interval regions are simulated as low-density non-magnetic mass units. A target critical speed range and multiple sets of distance parameters are set, and the critical speed of the rotor body under different sets of distance parameters is analyzed; wherein, each set of distance parameters includes the axial distances corresponding to multiple interval regions. By comparing and analyzing the multiple critical rotational speed values ​​corresponding to each set of distance parameters, the target distance parameter set with the largest critical rotational speed value is selected. Based on the target distance parameter set, the rotor body is optimized to obtain a high-speed, low-noise motor rotor structure that can improve the critical speed.

[0013] As one preferred embodiment, the step of setting a target critical speed range and multiple sets of distance parameters, and analyzing the critical speed of the rotor body under different sets of distance parameters, includes: According to the discrete sampling method, multiple sets of sample parameters are generated from the distance parameter set; Based on each set of sample parameters generated, the critical speed value corresponding to the first-order bending mode of the rotor body under each set of sample parameters is solved using the dynamic model.

[0014] As one preferred option, the comparative analysis of multiple critical rotational speed values ​​corresponding to each set of distance parameter values, and the selection of the target distance parameter set with the largest critical rotational speed value, includes: Using mechanical stress and rotor dynamic stability as constraints, a standard critical speed value that is smaller than the target critical speed range is selected from a plurality of critical speed values; Based on the multiple standard critical speed values, determine multiple sets of standard sample parameters that match the multiple standard critical speed values; From the set of multiple sets of standard sample parameters, select the target sample parameter value with the largest standard critical speed value; The optimization of the rotor body based on the target distance parameter set to obtain a high-speed, low-noise motor rotor structure that can improve the critical speed includes: The rotor body is optimized based on the target sample parameter values.

[0015] As one preferred embodiment, the step of using the dynamic model to solve for the critical speed value corresponding to the first-order bending mode of the rotor body under each set of sample parameters, based on the generated sample parameter sets, includes: Based on each set of sample parameters, change the axial distance corresponding to any interval region in each set of sample parameters to shift the first-order bending mode node of the rotor body at both ends or a specific support position. The critical speed value corresponding to the first-order bending mode of the rotor body under the optimized sample parameter set is solved using the dynamic model.

[0016] Compared to traditional design methods, the optimization method provided in this application has the following advantages: In this embodiment, the continuous mass distribution of a traditional integral rotor is broken by the axial spacing region, allowing the rotor to form an independent, discrete mass distribution characteristic along the axial direction. This enables accurate control of the rotor's axial mass distribution, avoiding excessively low first-order critical speeds due to excessive mass concentration in the central part of the shaft system. Furthermore, by setting adjustable spacing regions between segments, the problem of difficulty in increasing the critical speed due to the inability to adjust the equivalent moment of inertia variation and mass distribution of the rotor system is solved. Then, utilizing the lightweight properties of the potting material, the axial mass and stiffness of the rotor can be redistributed without changing the total axial length and electromagnetic effective length of the rotor. This facilitates improving the first-order bending mode critical speed of the system by controlling the shaft mass distribution.

[0017] The high-speed motor and design method described above have the same advantages over existing technologies, which will not be elaborated here. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application 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.

[0019] Figure 1 A cross-sectional view of the overall structure of a high-speed, low-noise motor rotor structure provided in an embodiment of this application; Figure 2 A schematic diagram of the parameters of a traditional motor rotor structure; Figure 3 A schematic diagram of parameters for a high-speed, low-noise motor rotor structure provided in an embodiment of this application; Figure 4 This is a dynamic model diagram of a high-speed, low-noise motor rotor structure provided in an embodiment of this application; Figure 5 A first-order bending mode diagram of a high-speed, low-noise motor rotor structure provided in an embodiment of this application; Figure 6 Campbell's diagram of a traditional electronic rotor structure; Figure 7 Campbell diagram of a high-speed, low-noise motor rotor structure provided in an embodiment of this application.

[0020] Explanation of reference numerals in the attached figures: 1. Rotor core; 2. Segmented magnets; 3. Encapsulation section; 4. Sheath. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. Based on the embodiments of this application, any product that is the same as or similar to this application, derived by anyone under the guidance of this application or by combining features of this application with other prior art, falls within the protection scope of this application. Furthermore, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application.

[0022] To better understand the design concept and implementation mechanism of the technical solution proposed in this application, it is necessary to first explain the dynamic characteristics related to the critical speed in the high-speed motor rotor system.

[0023] The critical speed of a rotor system directly relates to whether resonance occurs during high-speed operation and is a key indicator for evaluating rotor structural stability. This indicator is closely related to the overall mass distribution of the rotor, shaft stiffness, and the connection methods between its components. The critical speed refers to the rotational speed at which the rotor's excitation frequency is close to its natural frequency. Near this speed, the rotor is prone to resonance, leading to a sharp increase in vibration amplitude, which in turn causes increased bearing load, increased noise, and may even cause structural damage or failure.

[0024] In applications such as aerospace, high-speed compressors, and high-power-density drives, the demand for higher motor speeds is increasingly prominent. Increasing speed not only helps improve power density and energy conversion efficiency within the same volume, but also enables miniaturization and weight reduction of equipment, thereby improving overall system performance. However, as speeds continue to increase, the rotor's operating speed will inevitably approach or even exceed its inherent critical speed range. Therefore, in achieving high-speed design, it is first necessary to increase the rotor's critical speed or optimize its distribution to keep it away from the actual operating speed range, ensuring that the rotor system maintains good dynamic stability and reliability under high-speed conditions.

[0025] However, in existing technologies, increasing the critical speed of the rotor usually requires significant adjustments to the overall structure of the motor. This can be achieved by increasing the shaft diameter, increasing the overall mass, improving bearing stiffness, or altering the support structure to enhance the overall shaft system stiffness. While these methods can increase the critical speed to some extent, they often alter the overall dimensions of the motor, assembly relationships, and system layout. This not only increases design complexity but may also lead to increased weight, higher costs, and difficulties in system matching, making direct implementation on existing motor structures difficult.

[0026] Therefore, how to optimize the mass distribution and structural form of the rotor, increase its critical speed and improve its vibration characteristics without changing the overall shaft structure of the rotor system has become a technical problem that urgently needs to be solved in this field.

[0027] In view of this, this application proposes a high-speed, low-noise motor rotor structure, specifically a rotor system with high stability and wide-speed-range operation based on rotor segmentation and controllable mass distribution optimization. Unlike the integral structure using a single magnet in the prior art, this application segments the rotor magnets along the axial direction, allowing the length of each segment to be set independently, and introduces an adjustable spacing structure, thereby forming a spaced distribution structure in the axial direction. Through this segmented design, the distributed mass and stiffness of the rotor can be redistributed without changing the rotor's outer diameter and the overall shaft connection relationship, making the rotor's equivalent mass distribution more reasonable. Then, a low-density potting material is introduced into the spacing structure. By optimizing the length, spacing size, and physical properties of the segmented magnets 2, the inherent frequency characteristics of the rotor are controlled, thereby shifting its critical speed to a higher speed range, achieving effective control of the rotor system's critical speed, and thus improving its high-speed operation stability.

[0028] Based on the above description, the technical solution of this application will be further described in detail as follows: Reference Figure 1 As shown, Figure 1 This is a cross-sectional view of the overall structure of the high-speed, low-noise motor rotor structure shown in this application. This application proposes a high-speed, low-noise motor rotor structure, comprising: a rotor body, the rotor body being divided into at least two rotor segments along the axial direction, with an interval region formed between two axially adjacent rotor segments; at least one potting section 3, each potting section 3 being formed by potting material filling each interval region; wherein the density of the potting material is less than the average density of the rotor segments, and it is composed of a non-magnetic material.

[0029] In this embodiment, the rotor body is the rotating main body of the motor, and may include a shaft and permanent magnets sleeved or fixed to the outer periphery of the shaft. The rotor body is divided into N independent rotor segments along the axial direction, where N≥2 and is an integer. The rotor segments are spaced apart along the axial direction. It should be understood that "rotor segments" can be segments based on structural entities (such as segmented magnets 2, iron core segments), or equivalent segments based on functional area division, so as to form a discontinuity in mass distribution along the axial direction. This segmented structure can replace the traditional uniformly distributed rotor shaft, achieving a more flexible mass layout while ensuring overall mechanical strength and manufacturing feasibility.

[0030] An interval region is formed between two adjacent rotor segments in the axial direction, that is, N interval regions are formed between N rotor segments. One physical interval. The interval region extends along the rotor axis, and its radial range preferably matches the radial cross-section of adjacent rotor segments to ensure that the N rotor segments are independent and separated from each other. The axial length of the rotor segments and the width of the interval region, i.e., the axial distance between two rotor segments, are optimized and determined according to a preset critical speed increase target. During the design process, the axial lengths of each rotor segment can be the same or different. Each interval region can be evenly distributed or non-uniformly distributed to adjust the axial mass distribution and modal characteristics of the rotor. Preferably, the width of each interval region is non-uniformly distributed to specifically adjust the first-order bending mode of the rotor.

[0031] Specifically, the rotor body includes a rotor core 1 and multiple segmented magnets 2. The multiple segmented magnets 2 are axially spaced and fitted onto the rotor core 1, with gaps formed between adjacent segmented magnets 2. Each segmented magnet 2 is an annular structure, with its inner diameter matching the outer diameter of the rotor core 1. They can be installed onto the rotor core 1 through interference fit, adhesive bonding, or mechanical locking. Preferably, the outer diameter of each segmented magnet 2 is consistent to ensure the geometric continuity and balance of the rotor's outer circle. In the axial direction, the segmented magnets 2 can be equally spaced, or they can be distributed with non-equal spacing according to the rotor dynamics design requirements, thereby coordinating with the formed gaps to control the rotor's mass distribution and modal characteristics.

[0032] Furthermore, the interval region preferably runs radially between two adjacent segmented magnets 2, so that the adjacent segmented magnets 2 are physically completely decoupled, reducing axial eddy current losses under high-speed operation. At the same time, by changing the ratio of the rotor's axial bending stiffness to its mass distribution, the resonant frequency within the operating speed range is avoided.

[0033] The radial outer contour of the interval region is basically flush with the outer surface of the segmented magnet 2, so that the potting section 3 formed by the low-density potting material filled in the interval region is flush with the outer surface of the segmented magnet 2, thus ensuring the smoothness and flatness of the rotor's outer circle. Then, a sheath 4 is fitted onto the outer surface of the flat segmented magnet 2 and the potting section 3, with both ends of the sheath 4 being flush with the sides of the segmented magnet 2 at both edges.

[0034] like Figure 2 and Figure 3 As shown, exemplarily, the axial distance / width of the interval region is H. i Where i = 1, 2, ..., N 1, where H i This represents the axial distance between the i-th segment and the (i+1)-th segment. Each segment has a magnet of length 2, which is the axial length L of the rotor segment. i Satisfy: ∑L i =Leff, where Leff is the electromagnetic effective length of the motor. The total width of the interval region is ∑H. i (Axial width H of N-1 interval regions) i (and the sum) and the total rotor length L (the axial length L of the N rotor segments) i The ratio of ( ) to ( ) is determined based on the preset critical speed increase target.

[0035] Preferably, the axial length L of each rotor segment i The same applies to the axial length L of each rotor segment. i All segments are L1, and L1 satisfies: L1 = L / N. Where L is determined based on the axial length of the traditional rotor, and N is the number of rotor segments. Through this equal division design, the sum of the total axial lengths of each rotor segment can be kept consistent with that of the traditional rotor. This ensures that the motor maintains a torque output capability comparable to the traditional structure under different operating conditions, while keeping the overall effective electromagnetic length essentially unchanged. Furthermore, each rotor segment forms a discrete distribution structure in the axial direction, allowing each segment to participate as an independent mass unit in adjusting the rotor's dynamic characteristics, thereby avoiding dynamic imbalance problems caused by local mass concentration, eccentricity, or uneven distribution. Another preferred embodiment is that the axial length H of each interval region... i They can be the same or different, for example, H1, H2...H N-1 They can be completely equal, partially equal, or completely unequal. By considering each H... iIndependent adjustment can alter the continuity of the rotor's axial mass distribution, transforming it from a traditional uniform distribution system into a specific discrete distribution system. By rationally configuring the axial distance of each interval region, the first-order bending mode of the rotor can be adjusted, causing a shift in the mode shape's node position and thus increasing the critical speed of the corresponding mode. Preferably, based on simulation results from the design phase and model experimental verification, the axial distance H of each interval region... i The non-uniform distribution allows for flexible mass compensation for rotor shaft vibration modes. In this embodiment, the design process can be based on a rotor dynamics model (such as a finite element model or a transfer matrix method model), with the improvement of the critical speed as the optimization objective. The axial distance of each interval region can be parametrically designed and simulated to obtain a mass distribution scheme that meets specific operating conditions. Therefore, this application achieves a simplified design of rotor dynamics characteristics using the axial distance parameter of the interval region as a control factor. Compared to the traditional method of increasing the critical speed simply by increasing stiffness or modifying the overall structure, it offers greater design flexibility and engineering applicability.

[0036] It should be noted that in other embodiments, the axial lengths of each rotor segment can be set to be the same or not exactly the same, all of which can achieve non-uniform distribution of the interval regions and enable targeted optimization for specific vibration modes. In the preferred embodiment, using equal-length segments helps simplify the manufacturing process and improves structural symmetry and uniformity, ensuring the dynamic balance performance of the rotor. It should be noted that the specific number of interval regions, axial distance parameters, and dimensional parameters can all be adjusted according to different application scenarios, and this embodiment does not impose specific limitations on them.

[0037] Furthermore, a potting section 3 is provided in each interval region. The potting section 3 is formed by potting material filled in the corresponding interval region, which is used to adjust the overall mass distribution characteristics of the rotor structure while ensuring structural integrity. The density of the potting material is less than the average density of the rotor segments, forming an alternating distribution structure of high-density segments and low-density intervals in the axial direction, thereby changing the overall mass distribution characteristics of the rotor. Preferably, the potting material is a non-magnetic material to avoid adverse effects on the distribution of the air gap magnetic field of the motor. In some embodiments, the potting material should also have a certain degree of high thermal stability to ensure that the geometry and mechanical stiffness of the axial interval region remain stable under the centrifugal force and temperature rise generated by the high-speed rotation of the rotor shaft.

[0038] In some embodiments, the potting section 3 can be fixed between two adjacent rotor sections by means of interference fit, casting, or other methods. In a preferred embodiment, the potting material is directly poured in situ within the interval area and cured to form an integral structure, thereby improving assembly accuracy and enhancing structural integrity.

[0039] In summary, by breaking the continuous mass distribution of a traditional integral rotor through axially spaced regions, the rotor develops an independent, discrete mass distribution characteristic along the axial direction. This allows for precise control of the rotor's axial mass distribution, avoiding dynamic imbalances caused by localized mass concentration or uneven distribution. Furthermore, by setting adjustable intervals between segments, the problem of difficulty in adjusting the equivalent moment of inertia and mass distribution of the rotor system, which hinders the improvement of critical speed, is solved. Then, utilizing the lightweight properties of the potting material, the axial mass and stiffness of the rotor can be redistributed without changing the total axial length and electromagnetic effective length. This facilitates the improvement of the system's first-order bending mode critical speed by controlling the shaft mass distribution.

[0040] Then, by optimizing the length of the segmented magnets 2, the parameters of the spacing regions, and the physical properties of the potting material, the inherent frequency characteristics of the rotor can be controlled, thereby shifting its critical speed to a higher speed range and avoiding overlap or proximity with the actual operating speed of the motor. Compared to the traditional integral segmented magnet 2 structure, this application directly introduces adjustable axial discrete features into the shaft system structure, giving the rotor dynamics performance a higher degree of design freedom. Thus, the embodiments of this application can not only effectively improve the critical speed of the high-speed motor rotor, but also improve the vibration response and noise level during operation, thereby enhancing the overall stability and reliability of the motor operation, and has good engineering application value.

[0041] In one or more embodiments of this application, the interval regions are not simply mechanical connectors, but have a defined functional positioning, which can be controlled by adjusting the axial distance H between each interval region. i This effectively regulates the mass distribution characteristics and moment of inertia variation of the entire rotor system. Within these interval regions, the potting material must meet the following requirements: low density (e.g., epoxy resin, which has a density far lower than metal, should be used in potting section 3 to reduce the mass of the interval region); non-magnetic to prevent loss of effective torque; and high thermal stability to ensure structural integrity during long-term high-speed operation. Based on these considerations, the potting material can be one or more combinations of resin-based materials (such as epoxy resin, polyurethane, etc.), high-performance composite materials (such as carbon fiber reinforced resin matrix composites, glass fiber reinforced composites, etc.), lightweight metal materials (such as aluminum alloys, magnesium alloys), or ceramic-based materials (such as oxide ceramics, non-oxide ceramic materials, etc.), thereby achieving an optimal balance between density, strength, and stability.

[0042] It is worth mentioning that if only the interval regions are set without filling material, the mass distribution characteristics and moment of inertia variation of the entire rotor system can be adjusted by designing the parameters of the interval regions, thus solving the problem of difficulty in optimizing the critical speed. However, the weak connection structure formed between adjacent rotor segments in the axial direction leads to a decrease in the stiffness continuity of the overall rotor structure, which can easily cause abrupt changes in structural stiffness and insufficient connection reliability under high-speed rotation conditions. Therefore, in this application, by filling the interval regions with low-density potting material to form potting sections 3, the mass distribution control capability brought about by the segment design is retained, so that the rotor still exhibits the characteristic of alternating "high density-low density" along the axial direction, thereby effectively adjusting the equivalent moment of inertia distribution and improving the critical speed. At the same time, the potting sections 3, as a continuous functional medium filled between each rotor segment, can form a transition connection structure in the axial direction, avoiding abrupt changes in stiffness and mass, which is conducive to improving the integration of the overall structure, enhancing the resistance to centrifugal separation and long-term operational reliability. Therefore, compared to the scheme that relies solely on interval regions to achieve segmented adjustment of mass distribution, this embodiment achieves a comprehensive improvement in structural continuity, stiffness transition, and stability while maintaining the optimization effect of mass distribution, thereby increasing the critical speed while taking into account structural safety and engineering feasibility.

[0043] In conjunction with the above embodiments, during the design process, based on the rotor dynamics model (such as the finite element model or the transfer matrix method model), with the improvement of the critical speed as the optimization objective, the axial distance of each interval region can be parametrically designed and simulated to obtain a mass distribution scheme that meets the requirements of specific working conditions. Since the critical speed of the rotor system directly determines whether it is prone to resonance during high-speed operation, it is a core indicator for evaluating the stability of the rotor structure. The critical speed is closely related to the overall mass distribution of the system, the shaft stiffness, and the connection method between various components. Therefore, based on the above-mentioned novel rotor structure, corresponding to the second aspect, this application also provides a design method for a high-speed, low-noise motor rotor structure, used to design the high-speed, low-noise motor rotor structure as provided in the first aspect of this application. The method includes the following steps: S1. Establish a dynamic model of the rotor body of the rotor shaft system. The rotor body includes at least two rotor segments and an interval region located between two adjacent rotor segments. S2. Set the material properties of multiple rotor segments and multiple interval regions, simulate the rotor segments as high-density mass elements, and simulate the interval regions as low-density non-magnetic mass elements. S3. Set the target critical speed range and multiple sets of distance parameters, and analyze the critical speed of the rotor body under different sets of distance parameters; where each set of distance parameters includes the axial distances corresponding to multiple interval regions. S4. Compare and analyze the multiple critical rotation speed values ​​corresponding to each set of distance parameters, and select the target distance parameter set with the largest critical rotation speed value. S5. Based on the target distance parameter set, the rotor body is optimized to obtain a high-speed, low-noise motor rotor structure that can improve the critical speed.

[0044] Specifically, steps S1-S5, based on rotor dynamics analysis, use the axial distance parameter of the interval region as the core optimization variable to directionally increase the critical speed of the rotor system. In step S1, as... Figure 4 As shown, firstly, a dynamic model of the rotor shaft system is established. The rotor body includes a rotor core 1 and N segmented magnets 2, dividing the entire rotor structure into N continuous axial segments. Several segmented magnets 2 are adjacent to each other on the rotor core 1, forming N-1 interval regions. During the modeling process, the axial dynamic model of the rotor system can be constructed using the finite element method or the transfer matrix method, dividing the rotor core 1, segmented magnets 2, and the interval regions between the segmented magnets 2. Specifically, a complete three-dimensional model of the rotor body can be obtained using professional three-dimensional modeling software. This three-dimensional model is then imported into finite element analysis software for numerical simulation.

[0045] Each rotor segment / segment magnet 2 is modeled as a cylindrical or annular element with corresponding material parameters, thus setting multiple axial segments as high-density mass elements, whose material parameters may include density, elastic modulus, and Poisson's ratio. Simultaneously, the interval regions between adjacent axial segments are constructed as low-stiffness, low-density, and non-magnetic mass elements, whose material properties are set according to the actual filling material (e.g., epoxy resin), with a density lower than the axial segments and corresponding stiffness and elasticity parameters. Through dynamic modeling, the rotor forms an alternating distribution system of "high-density mass elements - low-density mass elements" in the axial direction.

[0046] In step S3, the target critical speed range and multiple sets of distance parameters are further defined. The widths H1, H2, ..., H of each interval region are set. N 1 is the variable to be optimized. Multiple interval regions correspond to several combinations, forming multiple sets of distance parameters to describe the axial distance distribution relationship of each interval region. After determining the number of interval regions, the axial length of each interval region is arbitrarily set. A specific combination of the axial lengths of all interval regions on the same rotor body constitutes a set of distance parameters. The axial distances of each interval region in each set of distance parameters can be evenly distributed, gradient distributed, or non-uniformly distributed, etc.

[0047] For example, the number of interval regions is N. 1. Then a set of distance parameters can be represented as: H = {H1, H2, ..., H} N 1}, where H1 to H N 1 represents the axial distance / width of each interval region arranged sequentially along the rotor axis.

[0048] To achieve effective control over rotor dynamics, the distance parameter set can be constructed in various forms, but is not limited to these: 1. An equidistant parameter set, where each interval region has the same width, i.e.: H1= H2=…= H N 1.

[0049] 2. Linear gradient parameter set, where the width of each interval region varies linearly along the axial direction, for example, gradually increasing or decreasing from one end to the other, i.e.: H i = H1+ (i 1) ΔH (i = 1, 2, …, N) 1), where ΔH is the gradient step size. This setting is used to adjust the offset distribution of the rotor mass along the axial direction, thereby affecting the position of the mode node.

[0050] 3. Non-uniformly distributed parameter sets cause the width of the interval regions to be non-uniformly distributed, for example: H1≠H2≠…≠H N 1, or H1≠H2=…≠H N 1, or others. This setting is used to achieve targeted control of specific modes, serving as a key design approach to improve critical speed.

[0051] All H1, H2...H N-1 As variables, and setting the value range of each variable according to the rotor strength limit, by selecting different combinations of distance parameter sets and performing critical speed analysis on the corresponding rotor models, the influence of various mass distribution schemes on rotor dynamic characteristics can be evaluated, thereby selecting the optimal parameter combination as the target distance parameter.

[0052] Multiple sets of distance parameters can be generated manually; alternatively, they can be automatically generated within a given value range using parametric modeling. Further, step S3 also includes: S31. Based on the discrete sampling method, generate multiple sets of sample parameters from the distance parameter set; S32. Based on each set of sample parameters, change the axial distance corresponding to any interval region in each set of sample parameters to offset the first bending mode node of the rotor body at both ends of the rotor body or a specific support position. S33. Use the dynamic model to solve for the critical speed value corresponding to the first-order bending mode of the rotor body under the optimized sample parameter set.

[0053] Specifically, the width parameters H1, H2, ..., H of each interval region are... N-1 Each value is limited to its corresponding range. Manual input of values ​​is time-consuming. Based on this, a discrete sampling method is used to generate feasible parameter combinations within a reasonable range. Each set of sample parameters corresponds to a set of optimal axial distance combinations. For example, to improve computational efficiency, orthogonal experimental design, Latin hypercube sampling (LHS), or random sampling can be used to select representative sample points from several interval regions. LHS is an efficient multidimensional spatial sampling method that ensures sample points are evenly distributed within the range of each design variable, avoiding sample clustering, thus revealing the characteristics of the design space to the maximum extent with the fewest possible sample points.

[0054] Subsequently, LHS is used to generate sample parameter sets from several width combinations (distance parameter sets) of interval regions, replacing the distance parameter sets. Dynamic analysis is then performed on the dynamic model corresponding to each generated sample parameter set to calculate its critical speed. The critical speed can be obtained by modal analysis to obtain the first and multiple natural frequencies of the rotor system, and determined in conjunction with the speed-frequency correspondence. In a preferred embodiment, the critical speed value corresponding to the first bending mode is used as the main evaluation index, and a preferred scheme with a critical speed value higher than the operating speed range is selected.

[0055] Specifically, the axial length H of each interval region can be... i (i = 1, 2, ..., N) 1) Perform modal sensitivity analysis to calculate the sensitivity of the first-order bending modal frequency to each axial length. Sensitivity analysis can identify parameters in key interval regions that significantly affect the first-order bending modal frequency, thus allowing for the determination of the axial distance H corresponding to one or more interval regions in each sample parameter set. i Key updates and adjustments are performed. This adjustment process can also alter the rotor's axial mass distribution, causing a shift in the positions of the first-order bending mode nodes, thus optimizing the matching relationship between the system's mass matrix and stiffness matrix. Preferably, during the adjustment process, corresponding intervals are selected for local adjustments based on the node shift direction, causing the first-order bending mode nodes of the rotor system to shift towards the rotor ends or specific support positions, thereby increasing the system's natural frequency by changing the equivalent vibrating mass. Therefore, targeted updates and adjustments to different H...i Combining these parameters can yield better combinations, forming a corresponding optimized set of sample parameters. For example... Figure 5 As shown, the critical speed value corresponding to the first-order bending mode is calculated by optimizing the sample parameter set, thereby gradually obtaining a rotor structure design scheme with a higher corresponding critical speed.

[0056] Through the aforementioned discrete sampling and modal solution process, the mapping relationship between multiple optimized sample parameter sets and their corresponding critical speeds can be obtained, providing a data foundation for subsequent selection of the optimal axial length parameter set. After obtaining the critical speed results corresponding to each optimized sample parameter set, they are compared and analyzed to select the target distance parameter set that achieves the maximum critical speed or meets the preset lifting target as the optimal distance parameter set.

[0057] Finally, each interval region in the target distance parameter set corresponds to a definite and optimal axial length. The rotor body is optimized by determining the definite interval regions and their definite structural parameters, including determining the specific position of each axial segment, the axial distance of each interval region, and the material distribution of the corresponding potting section 3, thereby obtaining a high-speed motor rotor structure that can improve the critical speed while taking into account low vibration and noise characteristics.

[0058] Therefore, the design method provided in this application designs a novel rotor structure, using the axial distance of the interval region as the optimization variable. Compared with the traditional method of increasing the critical speed by adjusting the overall structural stiffness, it can achieve fine control of the rotor dynamic characteristics without changing the overall structure of the motor, and has high engineering application value.

[0059] Step S4 further includes: S41. Using mechanical stress and rotor dynamic stability as constraints, select a standard critical speed value that is smaller than the target critical speed range from multiple critical speed values; S42. Based on multiple standard critical speed values, determine multiple sets of standard sample parameters that match the multiple standard critical speed values; S43. From multiple sets of standard sample parameters, select the target sample parameter value with the largest standard critical speed value; In the above embodiments, constraints are introduced to initially screen the calculated critical speed values. These constraints include mechanical stress constraints and rotor dynamic stability constraints. The mechanical stress constraints ensure that the maximum equivalent stress of the rotor at the corresponding speed does not exceed the allowable stress of the material. The rotor dynamic stability constraints prevent multi-mode coupling or unstable vibration phenomena within the target speed range. Under the premise of satisfying the above constraints, critical speed values ​​within the preset target critical speed range are selected as standard critical speed values; otherwise, other parameter sets that do not meet the constraints are not considered. Multiple standard critical speed values ​​are associated with corresponding distance parameter sets to obtain multiple sets of standard sample parameter sets. Each set of standard sample parameter sets corresponds to a set of axial distances H that satisfy the constraints and whose critical speed values ​​meet the requirements. i A specific combination of parameters is then selected. Subsequently, from multiple sets of standard sample parameters, the parameter combination that maximizes or most closely approximates the target upper limit of the critical speed is chosen as the target sample parameter value. Through a constraint mechanism, it is ensured that the selected target sample parameter values ​​not only improve the critical speed but also meet the engineering application requirements in terms of strength and stability, thereby guaranteeing the safety and reliability of the final design scheme.

[0060] Correspondingly, step S5 includes: S51. Optimize the rotor body based on the target sample parameter values.

[0061] In the simulation phase, after optimizing the blades through steps S1-S5, the optimized scheme can be experimentally verified. In the model testing phase, the optimized rotor body can be used as a standard, and a high-speed, low-noise motor rotor structure with a consistent body model can be prepared by scaling up or down proportionally. Specifically, using the optimized rotor body structure as a standard model, it can be scaled up or down proportionally according to actual application requirements to adapt to motor designs of different specifications or power levels. When performing dimensional transformations, it is preferable to maintain the proportional relationship between each rotor segment and interval region to ensure that the rotor dynamic characteristics (especially the critical speed improvement effect) are consistent or similar at different dimensions.

[0062] It should be noted that, for the method embodiments, the embodiments of this application are not limited to the described order of actions, because according to the embodiments of this application, some steps may be performed in other orders or simultaneously.

[0063] To verify the effectiveness of the proposed high-speed, low-noise motor rotor structure in improving critical speed, rotor system dynamic models were constructed using both a traditional integral rotor structure and the optimized high-speed, low-noise motor rotor structure of this application. Campbell diagram analysis was then performed based on these dynamic models. To ensure fairness in the comparison, the two rotor models maintained consistency in terms of total axial length, outer diameter, basic material parameters, and bearing support conditions. Under the same boundary conditions, speed-scanning modal analysis was performed on both rotor models to calculate the first-order bending mode frequency at different speeds, and Campbell diagrams of the rotor systems were plotted. During the analysis, forward and reverse precession modes were distinguished, and the resulting diagrams are shown below. Figure 6 and Figure 7 Campbell diagrams of the rotor body of a conventional motor and the optimized rotor body are shown respectively. Figure 6 and Figure 7 middle, Figure 6 Campbell's diagram of a conventional motor rotor body; Figure 7 This is a Campbell's diagram of the optimized rotor body, where the horizontal axis represents rotor speed and the vertical axis represents modal frequencies. From... Figure 6 and Figure 7 As shown in the two provided Campbell diagrams, the critical speed under the corresponding first-order bending mode is determined by identifying the intersection point of the excitation frequency line (black diagonal line) and the rotor's first-order bending mode natural frequency line (green horizontal line) in the Campbell diagram. The results show that the critical speeds corresponding to forward and reverse precession of the conventional high-speed motor rotor structure are 51385 rpm and 51604 rpm, respectively; while with the novel high-speed motor rotor structure proposed in this application, the critical speeds corresponding to forward and reverse precession are increased to 56344 rpm and 56497 rpm, respectively. Comparative analysis shows that in this embodiment, by adjusting the rotor's axial mass distribution and modal characteristics, this application effectively improves the first-order bending mode frequency of the rotor system, increasing the critical speed by approximately 10%. This result demonstrates that the novel rotor structure proposed in this application can significantly improve rotor dynamic performance without changing the overall rotor size and electromagnetic effective length, thereby improving the operating stability of the high-speed motor and reducing vibration noise.

[0064] Thirdly, this application also provides a high-speed motor, including the high-speed, low-noise motor rotor structure as provided in the first aspect of this application.

[0065] It should be noted that, for the above-described high-speed motor embodiments, since the high-speed low-noise motor rotor structure already possesses the technical effects mentioned above, the high-speed motor designed using this high-speed low-noise motor rotor structure should also possess similar technical effects, so it will not be elaborated here.

[0066] It should also be noted that, in this document, the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and 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 of this application. Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device.

Claims

1. A high-speed, low-noise motor rotor structure, characterized in that, The structure includes: The rotor body is divided into at least two rotor segments along the axial direction, and an interval region is formed between two axially adjacent rotor segments. At least one potting section, each of the potting sections being formed by potting material filling each of the interval regions; wherein the density of the potting material is less than the average density of the rotor segments, and is composed of a non-magnetic material.

2. The high-speed, low-noise motor rotor structure according to claim 1, characterized in that, The potting material includes at least one of epoxy resin, high-performance composite material, and ceramic matrix material.

3. The high-speed, low-noise motor rotor structure according to claim 1, characterized in that, The rotor body includes a rotor core and multiple segmented magnets. The multiple segmented magnets are axially spaced on the rotor core, and the interval region is formed between two adjacent segmented magnets.

4. The high-speed, low-noise motor rotor structure according to claim 3, characterized in that, The axial lengths of the multiple segmented magnets are the same; and / or, The axial distances of the multiple interval regions are non-uniformly distributed to achieve mass compensation for the rotor shaft system vibration mode.

5. The high-speed, low-noise motor rotor structure according to claim 3, characterized in that, The interval region isolates two adjacent segmented magnets.

6. A high-speed motor, characterized in that, The rotor structure of the high-speed, low-noise motor as described in any one of claims 1-5 is included.

7. A design method for a high-speed, low-noise motor rotor structure, characterized in that, A method for designing a high-speed, low-noise motor rotor structure as described in any one of claims 1-5 includes: A dynamic model of the rotor body of the rotor shaft system is established, wherein the rotor body includes at least two rotor segments and an interval region located between two adjacent rotor segments; The material properties of multiple rotor segments and multiple interval regions are set, the rotor segments are simulated as high-density mass units, and the interval regions are simulated as low-density non-magnetic mass units. A target critical speed range and multiple sets of distance parameters are set, and the critical speed of the rotor body under different sets of distance parameters is analyzed; wherein, each set of distance parameters includes the axial distances corresponding to multiple interval regions. By comparing and analyzing the multiple critical rotational speed values ​​corresponding to each set of distance parameters, the target distance parameter set with the largest critical rotational speed value is selected. Based on the target distance parameter set, the rotor body is optimized to obtain a high-speed, low-noise motor rotor structure that can improve the critical speed.

8. The design method for a high-speed, low-noise motor rotor structure according to claim 7, characterized in that, The defined target critical speed range and multiple sets of distance parameters are used to analyze the critical speed of the rotor body under different sets of distance parameters, including: According to the discrete sampling method, multiple sets of sample parameters are generated from the distance parameter set; Based on each set of sample parameters generated, the critical speed value corresponding to the first-order bending mode of the rotor body under each set of sample parameters is solved using the dynamic model.

9. The design method for a high-speed, low-noise motor rotor structure according to claim 8, characterized in that, The comparative analysis of multiple critical rotational speed values ​​corresponding to each set of distance parameters filters out the target distance parameter set with the largest critical rotational speed value, including: Using mechanical stress and rotor dynamic stability as constraints, a standard critical speed value that is smaller than the target critical speed range is selected from a plurality of critical speed values; Based on the multiple standard critical speed values, determine multiple sets of standard sample parameters that match the multiple standard critical speed values; From the set of multiple sets of standard sample parameters, select the target sample parameter value with the largest standard critical speed value; The optimization of the rotor body based on the target distance parameter set to obtain a high-speed, low-noise motor rotor structure that can improve the critical speed includes: The rotor body is optimized based on the target sample parameter values.

10. The design method for a high-speed, low-noise motor rotor structure according to claim 8, characterized in that, The step of using the dynamic model to solve for the critical speed value corresponding to the first-order bending mode of the rotor body under each set of sample parameters, based on the generated sample parameter sets, includes: Based on each set of sample parameters, change the axial distance corresponding to any one of the interval regions in each set of sample parameters to shift the first-order bending mode nodes of the rotor body towards both ends of the rotor body or a specific support position. The critical speed value corresponding to the first-order bending mode of the rotor body under the optimized sample parameter set is solved using the dynamic model.

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