Core for servo motor

Abstract

The application discloses an iron core applied to a servo motor and belongs to the technical field of motors. The iron core comprises a stator and a rotor. The rotor is in a cylindrical structure as a whole, the stator is in a ring structure as a whole, the stator is sleeved on the rotor, the stator and the rotor are coaxially arranged, a spacing exists between the inner wall surface of the stator and the outer circumferential surface of the rotor, a plurality of magnetic steels are arranged in the spacing, the plurality of magnetic steels are arranged in a ring shape along the outer circumferential surface of the rotor, the thicknesses of the plurality of magnetic steels in the radial direction of the rotor are not completely equal, an air gap is arranged between two adjacent magnetic steels, and the sizes of at least two air gaps in the plurality of air gaps are not completely equal. The application adopts the non-equal-thickness design of the magnetic steels, optimizes the back electromotive force waveform, reduces high-order harmonics, reduces high-frequency heating, and thus the efficiency and reliability of the motor are improved.

Description

Technical Field

[0001] This application relates to the field of motor technology, and in particular to an iron core for use in servo motors. Background Technology

[0002] In the fields of modern industrial automation and precision control, servo motors, as high-precision and high-performance power drive devices, are widely used in various precision machinery, robots, CNC machine tools, and other equipment. One of their core components—the iron core—plays a crucial role in the motor's performance, efficiency, and reliability.

[0003] Relevant prior art, such as the Chinese patent application "Magnetic Steel Motor Core" (application number CN201120566135.6), discloses a body comprising multiple circumferentially distributed magnetic steel slots, each slot containing two independently arranged magnetic steel plates. The body is an inner rotor. A shaft hole, capable of mates with the motor shaft, is located in the center of the body. By dividing the existing single magnetic steel plate in two and installing two magnetic steel plates in each pole, material is saved. Because the size of each magnetic steel plate is reduced, the air gap between the assembled rotor and stator can be reduced, unaffected by the size of the magnetic steel, thus improving motor performance.

[0004] In existing permanent magnet servo motors, the basic structure is regular and repetitive. Although this design is simple, it generates high levels of harmonics during operation. These harmonics cause the motor's back EMF waveform to deviate from a sine wave, resulting in high-frequency heating, further reducing the motor's efficiency and reliability, and shortening its lifespan.

[0005] With the rapid development of industrial automation and intelligent manufacturing, the performance requirements for servo motors are becoming increasingly stringent, especially in terms of high-precision control, high-efficiency operation, and long lifespan. Therefore, there is an urgent need for a new type of servo motor core design that can effectively solve the problems existing in traditional designs and meet the high-performance demands of modern industry for servo motors. Utility Model Content

[0006] The technical problem to be solved by this application is to provide a core for servo motors, which adopts a non-uniform thickness design of magnets, optimizes the back EMF waveform, reduces high-order harmonics, and reduces high-frequency heat generation, thereby improving motor efficiency and reliability.

[0007] The technical solution adopted in this application is as follows: an iron core for a servo motor, including a stator and a rotor. The rotor is cylindrical in shape, and the stator is an annular in shape. The stator is sleeved on the outside of the rotor and the stator and rotor are coaxially arranged. There is a gap between the inner wall of the stator and the outer circumferential surface of the rotor. Multiple magnets are arranged in the gap. The multiple magnets are arranged in a ring along the outer circumferential surface of the rotor. The thickness of the multiple magnets is not completely equal along the radial direction of the rotor. An air gap is provided between two adjacent magnets. At least two of the multiple air gaps have different sizes.

[0008] Compared with existing technologies, the advantages of this application are as follows: First, the use of a non-uniform air gap structure can effectively change the distribution of the air gap magnetic field. This structure makes the static cogging torque of the motor less than 1% of the rated torque. Because when the air gap is non-uniform, the harmonic components of the air gap magnetic field are suppressed, and the cogging torque mainly comes from the harmonics of the air gap magnetic field, thus the cogging torque is significantly reduced. Due to the reduction in cogging torque, the motor is smoother during startup and low-speed operation. The non-uniform air gap structure reduces the motor's vibration and jitter under these operating conditions, contributing to improved overall performance.

[0009] Secondly, the traditional uniform magnet thickness design causes the back EMF waveform of the motor to deviate from a sine wave, generating higher harmonics. However, the non-uniform magnet thickness design in this application makes the back EMF waveform closer to a sine wave. This is because magnets of different thicknesses generate different magnetic fluxes in a magnetic field. By rationally designing the magnet thickness, the distribution of the air gap magnetic field can be adjusted, thereby improving the back EMF waveform, ensuring it is close to a sine wave, reducing higher harmonics during motor operation, and thus reducing high-frequency heating and improving motor efficiency.

[0010] In some embodiments of this application, the outer peripheral surface of the rotor is provided with a plurality of embedding grooves, which are arranged regularly and extend through both sides of the rotor along the axial direction of the rotor.

[0011] The embedded slot design facilitates the installation and fixation of the magnets. The regularly arranged embedded slots ensure accurate positioning of the magnets during installation, improving assembly efficiency and precision. Simultaneously, the design extending through both sides of the rotor ensures that the magnets rotate synchronously with the rotor, enhancing structural stability.

[0012] Preferably, the rotor of this application has 7-12 embedded slots distributed on its outer circumferential surface, which can ensure uniform distribution of magnets and optimize the distribution of the air gap magnetic field. The above-mentioned number range can ensure a sufficient number of magnets to generate sufficient magnetic field strength, while avoiding the structural complexity and increased cost caused by too many magnets.

[0013] In some embodiments of this application, the magnets correspond one-to-one with the embedding grooves, the inner end of the magnet is located in the embedding groove, and the inner surface of the magnet is in contact with the bottom surface of the embedding groove.

[0014] This design ensures the magnet is stably fixed within the embedding groove, reducing vibration and displacement during operation. The close contact between the inner surface and the bottom of the embedding groove improves magnetic field uniformity, reduces magnetic field leakage, and increases motor efficiency.

[0015] In some embodiments of this application, the inner surface of the magnet has an arc segment cross-section, and the outer surface of the magnet is a curved surface with an arc segment cross-section; the curvature of the outer surface of the magnet is greater than the curvature of the inner surface. The arc segment design of the inner surface of the magnet can better fit the rotor surface and reduce magnetic field leakage; the greater curvature of the outer surface can increase the contact area between the magnet and the air gap, further optimizing motor performance.

[0016] In some embodiments of this application, the two side walls of the embedding groove are inclined surfaces, and the angle between the side wall of the embedding groove and the bottom surface is an acute angle; the two side surfaces of the magnet are inclined surfaces adapted to the embedding groove. The inclined surface design can increase the contact area between the embedding groove and the magnet, and improve the fixing stability of the magnet.

[0017] In some embodiments of this application, a limiting protrusion is provided between the embedding grooves. The limiting protrusion is arranged parallel to the axial direction of the rotor, and its cross-section is trapezoidal. The limiting protrusion can effectively restrict the position of the magnet and prevent the magnet from shifting during operation. The trapezoidal cross-section design can increase the structural strength of the limiting protrusion and also better match the installation of the magnet.

[0018] In some embodiments of this application, the gap between the limiting protrusion, the magnets on both sides of the limiting protrusion, and the inner wall of the stator together constitutes an air gap. By reasonably setting the dimensions of the limiting protrusion and the magnets, the size of the air gap can be precisely controlled to ensure that the static cogging torque of the motor is less than 1% of the rated torque, thus meeting the requirements of high-precision control.

[0019] In some embodiments of this application, the rotor surface is provided with multiple ventilation slots arranged in a regular circular pattern. Each ventilation slot corresponds one-to-one with a magnet, and the ventilation slots and the embedded slots are located on the same radial direction. The design of the ventilation slots effectively improves the heat dissipation performance of the motor. The regularly arranged ventilation slots ensure uniform heat dissipation, reducing the temperature rise of the motor during operation. The one-to-one correspondence between the ventilation slots and magnets better guides airflow, improving heat dissipation efficiency.

[0020] In some embodiments of this application, rivet holes are provided between two adjacent ventilation slots, and the diameters of the rivet holes are not exactly equal. Rivet holes of different diameters can provide a variety of connection methods, enhancing the stability of the rotor connection. This design also allows for the selection of appropriate rivet holes according to different assembly requirements, improving assembly flexibility and reliability.

[0021] In some embodiments of this application, the stator includes multiple core blocks, each core block being I-shaped. Each core block includes an outer yoke, an inner yoke, and teeth. The outer yokes of the multiple core blocks are connected end-to-end to form a ring, and there is a gap between adjacent inner yokes. A coil is wound around the teeth. The I-shaped core block design optimizes the magnetic circuit distribution, ensuring uniformity in each segment of the magnetic circuit. The ring-shaped connection of the outer yokes enhances the overall structural strength of the stator. The gap between adjacent inner yokes reduces magnetic circuit losses and improves motor efficiency. Through a reasonable structural design and appropriate dimensions, the stator ensures uniformity in each segment of the magnetic circuit, ensuring the motor achieves maximum efficiency.

[0022] Based on common knowledge in the field, the above-described embodiments can be combined arbitrarily. Attached Figure Description

[0023] The present application will be described in further detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the present application. Furthermore, unless specifically indicated, the drawings are only schematic representations of the composition or structure of the described objects and may contain exaggerated depictions, and the drawings are not necessarily drawn to scale.

[0024] Figure 1 This is a schematic diagram of the structure of this application; Figure 2 This is a schematic diagram of the front structure of this application; Figure 3 This is a schematic diagram of the cross-section of this application; Figure 4 for Figure 3 A sectional view of section AA in the middle.

[0025] The specific explanations of the reference numerals in the attached drawings are as follows: 1. Stator; 2. Rotor; 3. Magnet; 4. Air gap; 5. Embedded groove; 6. Limiting protrusion; 7. Ventilation groove; 8. Rivet hole; 9. Core segment; 9a. Outer yoke; 9b. Inner yoke; 9c. Tooth. Detailed Implementation

[0026] The present application will now be described in detail with reference to the accompanying drawings.

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] Iron cores used in servo motors, as shown in Example 1 Figure 1 , Figure 2As shown, the system includes a stator 1 and a rotor 2. The rotor 2 has a cylindrical structure, while the stator 1 has a ring-shaped structure. The stator 1 is fitted over the rotor 2 and is coaxially arranged. There is a gap between the inner wall of the stator 1 and the outer circumferential surface of the rotor 2. Multiple magnets 3 are arranged in a ring along the outer circumferential surface of the rotor 2. The thickness of the multiple magnets 3 is not completely equal along the radial direction of the rotor 2, which makes the back EMF waveform closer to a sine wave. This is because magnets 3 of different thicknesses generate different magnetic fluxes in the magnetic field. By reasonably designing the thickness of the magnets 3, the distribution of the magnetic field in the air gap 4 can be adjusted, thereby improving the back EMF waveform, ensuring that the back EMF waveform is close to a sine wave, reducing high-order harmonics during motor operation, thus reducing high-frequency heating and improving motor efficiency.

[0029] An air gap 4 is provided between two adjacent magnets 3, and at least two of the multiple air gaps 4 have different dimensions. This non-uniform air gap 4 structure effectively alters the distribution of the magnetic field in the air gaps. This structure results in the motor's static cogging torque being less than 1% of its rated torque.

[0030] Example 2, as Figures 1 to 4 As shown, the outer circumferential surface of the rotor 2 is provided with multiple embedding grooves 5, which are regularly arranged and extend through both sides of the rotor 2 along its axial direction. The design of the embedding grooves 5 facilitates the installation and fixation of the magnets 3. The regularly arranged embedding grooves 5 ensure accurate positioning of the magnets 3 during installation, improving assembly efficiency and precision. Simultaneously, the design of extending through both sides of the rotor 2 ensures that the magnets 3 rotate synchronously with the rotor 2, enhancing structural stability.

[0031] Preferably, the rotor 2 of this application has 7-12 embedded slots 5 distributed on its outer peripheral surface, which can ensure that the magnets 3 are evenly distributed and optimize the magnetic field distribution in the air gap 4. The above-mentioned range of numbers can ensure a sufficient number of magnets 3 to generate sufficient magnetic field strength, while avoiding the structural complexity and increased cost caused by too many magnets 3.

[0032] The magnets 3 and 5 are paired one-to-one, with the inner end of the magnet 3 located within the groove 5 and the inner surface of the magnet 3 in contact with the bottom surface of the groove 5. This design ensures that the magnet 3 is stably fixed within the groove 5, reducing vibration and displacement during operation. The contact between the inner surface and the bottom surface of the groove 5 improves the uniformity of the magnetic field, reduces magnetic field leakage, and increases motor efficiency.

[0033] The inner surface of the magnet 3 has an arc-shaped cross-section, while the outer surface of the magnet 3 is curved, with the outer surface also having an arc-shaped cross-section. The curvature of the outer surface of the magnet 3 is greater than that of the inner surface. The arc-shaped design of the inner surface of the magnet 3 allows for better contact with the rotor 2 surface, reducing magnetic field leakage. The greater curvature of the outer surface increases the contact area between the magnet 3 and the air gap 4, further optimizing motor performance.

[0034] The two side walls of the embedding groove 5 are inclined surfaces, and the angle between the side wall of the embedding groove 5 and the bottom surface is an acute angle; the two side surfaces of the magnet 3 are inclined surfaces adapted to the embedding groove 5. The inclined surface design can increase the contact area between the embedding groove 5 and the magnet 3, and improve the fixing stability of the magnet 3.

[0035] A limiting ridge 6 is provided between the embedding grooves 5 and 2. The limiting ridge 6 is parallel to the axial direction of the rotor 2 and has a trapezoidal cross-section. The limiting ridge 6 can effectively restrict the position of the magnet 3 and prevent the magnet 3 from shifting during operation. The trapezoidal cross-section design can increase the structural strength of the limiting ridge 6 and also better match the installation of the magnet 3.

[0036] The limiting ridge 6, the gaps between the magnets 3 on both sides of the limiting ridge 6 and the inner wall of the stator 1 together constitute the air gap 4. By reasonably setting the dimensions of the limiting ridge 6 and the magnets 3, the size of the air gap 4 can be precisely controlled to ensure that the static cogging torque of the motor is less than 1% of the rated torque, thus meeting the requirements of high-precision control.

[0037] The rotor 2 has multiple ventilation slots 7 on its surface, arranged in a regular circular pattern. Each ventilation slot 7 corresponds one-to-one with a magnet 3, and the ventilation slots 7 and the embedded slots 5 are located on the same radial direction. The design of the ventilation slots 7 effectively improves the motor's heat dissipation performance. The regularly arranged ventilation slots 7 ensure uniform heat dissipation, reducing the temperature rise of the motor during operation. The one-to-one correspondence between the ventilation slots 7 and the magnets 3 better guides airflow, improving heat dissipation efficiency.

[0038] Rivet holes 8 are provided between two adjacent ventilation slots 7, and the diameters of the multiple rivet holes 8 are not exactly equal. Rivet holes 8 of different diameters can provide a variety of connection methods, enhancing the stability of the rotor 2 structure. This design also allows for the selection of appropriate rivet holes 8 according to different assembly requirements, improving assembly flexibility and reliability.

[0039] The stator 1 comprises multiple iron core blocks 9, each in an I-shape. Each iron core block 9 includes an outer yoke 9a, an inner yoke 9b, and a toothed portion 9c. The outer yokes 9a of the multiple iron core blocks 9 are connected end-to-end to form a ring. There is a gap between adjacent inner yokes 9b. A coil is wound around the toothed portion 9c. This I-shaped iron core block design optimizes the magnetic circuit distribution, ensuring uniformity in each segment of the magnetic circuit. The ring-shaped connection of the outer yokes 9a enhances the overall structural strength of the stator 1. The gap between adjacent inner yokes 9b reduces magnetic circuit losses and improves motor efficiency. Through a reasonable structural design and appropriate dimensions, the stator 1 ensures uniformity in each segment of the magnetic circuit, guaranteeing the motor reaches maximum efficiency.

[0040] The rest of the contents of Example 2 are the same as those of Example 1.

[0041] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The descriptions of the embodiments above are only for the purpose of helping to understand the present application and its core ideas. It should be noted that those skilled in the art can make several improvements and modifications to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. An iron core applied to a servo motor, characterized by, The device includes a stator (1) and a rotor (2). The rotor (2) is cylindrical in shape, and the stator (1) is annular in shape. The stator (1) is sleeved on the outside of the rotor (2). The stator (1) and the rotor (2) are coaxially arranged. There is a gap between the inner wall of the stator (1) and the outer circumferential surface of the rotor (2). Multiple magnets (3) are arranged in a ring along the outer circumferential surface of the rotor (2). The thickness of the multiple magnets (3) is not completely equal in the radial direction of the rotor (2). An air gap (4) is provided between two adjacent magnets (3). At least two of the multiple air gaps (4) have different sizes.

2. The core for a servo motor according to claim 1, wherein The outer circumferential surface of the rotor (2) is provided with multiple embedding grooves (5), which are arranged regularly and penetrate through both sides of the rotor (2) along the axial direction of the rotor (2).

3. The core for a servo motor according to claim 1, wherein The magnet (3) corresponds one-to-one with the embedding groove (5). The inner end of the magnet (3) is located in the embedding groove (5), and the inner surface of the magnet (3) is in contact with the bottom surface of the embedding groove (5).

4. The core for a servo motor according to claim 1, wherein The inner side of the magnet (3) has an arc segment in cross section, and the outer side of the magnet (3) has a curved surface. The outer side of the magnet (3) has an arc segment in cross section; the curvature of the outer side of the magnet (3) is greater than the curvature of the inner side of the magnet (3).

5. The core for a servo motor according to claim 2, wherein The two side walls of the embedding groove (5) are inclined surfaces, and the angle between the side wall of the embedding groove (5) and the bottom surface is an acute angle; the two sides of the magnet (3) are inclined surfaces adapted to the embedding groove (5).

6. The iron core for a servo motor according to claim 2, characterized in that, A limiting protrusion (6) is provided between the embedding groove (5) and the embedding groove (5). The limiting protrusion (6) is arranged parallel to the axial direction of the rotor (2), and the cross section of the limiting protrusion (6) is trapezoidal.

7. The iron core for a servo motor according to claim 6, characterized in that, The gap between the limiting protrusion (6), the magnets (3) on both sides of the limiting protrusion (6) and the inner wall of the stator (1) together constitutes the air gap (4).

8. The core for a servo motor according to claim 1, wherein The rotor (2) has multiple ventilation slots (7) on its surface. The ventilation slots (7) are arranged in a regular ring. The ventilation slots (7) correspond one-to-one with the magnets (3). The ventilation slots (7) and the embedded slots (5) are located on the same radial direction.

9. The core for a servo motor according to claim 8, wherein Rivet holes (8) are provided between two adjacent ventilation slots (7), and the diameters of the multiple rivet holes (8) are not completely equal.

10. The iron core for a servo motor according to claim 1, characterized in that, The stator (1) includes multiple iron core blocks (9), which are I-shaped in general. Each iron core block (9) includes an outer yoke (9a), an inner yoke (9b), and a toothed part (9c). The outer yokes (9a) of the multiple iron core blocks (9) are connected end to end to form a ring. There is a gap between two adjacent inner yokes (9b). A coil is wound around the toothed part (9c).

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