Rotor and stator assembly

Abstract

The utility model discloses a rotor and stator assembly, relates to the motor field, the rotor and stator assembly comprises a stator iron core and a rotor, the rotor is coaxially sleeved in the stator iron core, the stator iron core comprises a stator tooth portion, the stator tooth portion comprises a connecting portion and tooth shoe portions, the two sides of the connecting portion are respectively provided with the tooth shoe portions, and the tooth shoe portions are arranged on the connecting portion. The two tooth shoe parts are symmetrically arranged relative to the center line of the stator tooth part, one side, facing the rotor, of each tooth shoe part is provided with a cutting plane, the included angle between the cutting plane and the center line of the stator tooth part is 90 degrees, the distance between the edges, facing each other, of the two cutting planes is S, the extension distance of the cutting planes in the direction perpendicular to the inner diameter of the stator iron core is L, and L + L = 1 / 2S; each magnetic pole comprises an arc-shaped outer wall and an arc-shaped inner wall, the outer wall is close to the stator core, and the inner wall is close to the center of the rotor. The rotor and stator assembly provided by the technical scheme of the utility model can weaken the cogging torque and improve the control precision.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a rotor and stator assembly. Background Technology

[0002] With the continuous improvement of permanent magnet material performance, permanent magnet motors are increasingly widely used in high-performance speed and position control systems. However, in permanent magnet motors, the interaction between the permanent magnet and the slotted armature core inevitably generates cogging torque, leading to torque fluctuations, vibration, and noise, which affects the control accuracy of the system.

[0003] Cogging torque is a unique problem of permanent magnet motors and a key issue that must be considered and solved in the design and manufacturing of high-performance permanent magnet motors. Cogging torque will not disappear out of thin air; it can only be reduced through effective methods. Utility Model Content

[0004] The main objective of this invention is to provide a rotor and stator assembly that reduces cogging torque.

[0005] To achieve the above objectives, the present invention proposes a rotor and stator assembly, comprising a stator core and a rotor, wherein the rotor is coaxially mounted within the stator core.

[0006] The stator core includes:

[0007] The stator tooth section includes a connecting section and a tooth shoe section. The tooth shoe sections are respectively provided on both sides of the connecting section, and the two tooth shoe sections are symmetrically arranged about the center line of the stator tooth section. The tooth shoe section has a cutting plane on the side facing the rotor. The angle between the cutting plane and the center line of the stator tooth section is 90 degrees. The distance between the edges of the two cutting planes facing each other is S. In the direction perpendicular to the inner diameter of the stator core, the extension distance of the cutting plane is L, and L+L=1 / 2S;

[0008] The rotor includes:

[0009] The magnetic pole includes an outer wall and an inner wall arranged in an arc shape, the outer wall being close to the stator core and the inner wall being close to the rotor center.

[0010] In one embodiment, the inner and outer walls of the magnetic pole have equal radii.

[0011] In one embodiment, one end of the connecting portion is provided with an inner arc surface, and the two ends of the inner arc surface are respectively connected to the two cut surfaces.

[0012] In one embodiment, the stator core further includes a stator yoke, which is connected to one end of the connecting portion away from the toothed shoe portion, and the stator yoke and the connecting portion define a receiving space for accommodating a coil.

[0013] In one embodiment, the stator yoke and the stator teeth are integrally formed and defined to form a stator unit, and multiple stator units are provided, and the multiple stator units are sequentially spliced ​​along the circumferential direction to form the stator core.

[0014] In one embodiment, the accommodating spaces of two adjacent stator units are arranged opposite each other to form a accommodating cavity.

[0015] In one embodiment, the stator yoke is provided with a limiting groove on the side opposite to the connecting portion.

[0016] In one embodiment, the stator yoke has a protrusion at one end and a recess at the other end in the circumferential direction, and the protrusion and the recess of adjacent stator units cooperate with each other.

[0017] In one embodiment, the rotor further includes a rotor body, and multiple magnetic poles are provided and are evenly arranged on the outer wall of the rotor body in sequence along the circumferential direction of the rotor body, and the inner wall of the magnetic poles is in close contact with the rotor body.

[0018] In one embodiment, the magnetic pole further includes a connecting wall, with the connecting wall connected to both ends of the outer wall, and the two connecting walls are arranged parallel to each other, and the connecting wall is also connected to the inner wall.

[0019] This utility model's technical solution reduces cogging torque by optimizing the stator core structure. Specifically, the stator core's tooth shoe portion has a shaving plane on the rotor-facing side, with the angle between the shaving plane and the centerline of the stator teeth being 90 degrees. The distance between the edges of the two shaving planes facing each other is S, and the extension distance of the shaving planes in the direction perpendicular to the inner diameter of the stator core is L, where L + L = 1 / 2S. This optimization of the stator core structure simplifies the complexity of motor magnetic circuit optimization, improves R&D efficiency, and allows for rapid response to customer needs. Combined with the magnetic pole structure, this reduces the motor's cogging torque, thereby reducing torque fluctuations, vibration, and noise, improving system control accuracy, and reducing cogging torque and noise without affecting motor performance. It also reduces the no-load back EMF distortion rate and improves the sinusoidal nature of the waveform. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the structure of an embodiment of the rotor and stator assembly provided by this utility model;

[0022] Figure 2 A schematic diagram of the stator unit in an embodiment of the rotor and stator assembly provided by this utility model;

[0023] Figure 3 A schematic diagram of the magnetic pole structure of an embodiment of the rotor and stator assembly provided by this utility model;

[0024] Figure 4 A schematic diagram of permanent magnet material cutting magnetic poles in an embodiment of the rotor and stator assembly provided by this utility model;

[0025] Figure 5 The cogging torque diagram of a stator core motor with equal-radius tile-shaped magnetic poles and a cut-out plane;

[0026] Figure 6 The diagram shows the cogging torque of a stator core motor with equal-radius tile-shaped magnetic poles and a cut surface.

[0027] Figure 7 The output torque and torque pulsation diagram of a stator core motor with equal-radius tile-shaped magnetic poles and an uncut surface;

[0028] Figure 8 The output torque and torque pulsation diagram of a stator core motor with equal-radius tile-shaped magnetic poles and a cut surface;

[0029] Figure 9 The waveform of the no-load back electromotive force of a stator core motor with equal-radius tile-shaped magnetic poles and a cut-out plane;

[0030] Figure 10 The waveform of the no-load back electromotive force of a stator core motor with equal-radius tile-shaped magnetic poles and a cut surface.

[0031] Figure 11 The no-load back electromotive force FFT plot of a stator core motor with equal-radius tile-shaped magnetic poles and an uncut plane;

[0032] Figure 12 The FFT plot of the no-load back electromotive force of a stator core motor with equal-radius tile-shaped magnetic poles and a cut-out plane is shown.

[0033] Explanation of icon numbers:

[0034] 10. Stator core; 11. Stator unit; 20. Rotor;

[0035] 100. Stator teeth; 110. Connecting part; 111. Inner arc surface; 120. Tooth shoe part; 121. Chamfered surface;

[0036] 200, stator yoke; 210, limiting groove; 220, convex part; 230, concave part;

[0037] 300. Receiving cavity; 310. Receiving space;

[0038] 400, Magnetic pole; 410, Inner wall; 420, Outer wall; 430, Connecting wall;

[0039] 500. Rotor body.

[0040] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0041] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0042] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0043] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0044] In existing technologies, cogging torque is one of the unique problems of permanent magnet motors. It is a key issue that the design and manufacturing center of high-performance permanent magnet motors must consider and solve. Cogging torque will not disappear out of thin air; it can only be reduced through effective methods.

[0045] This utility model proposes a rotor and stator assembly.

[0046] Please see Figures 1 to 4 As shown, in one embodiment of this utility model, the rotor and stator assembly includes a stator core 10 and a rotor 20. The rotor 20 is coaxially fitted inside the stator core 10. The stator core 10 includes a stator tooth portion 100, which includes a connecting portion 110 and a tooth shoe portion 120. The connecting portion 110 has tooth shoe portions 120 on both sides, and the two tooth shoe portions 120 are symmetrically arranged about the center line of the stator tooth portion 100. The tooth shoe portion 120 has a chamfered surface 121 on the side facing the rotor 20, and the chamfered surface 121 and the center line of the stator tooth portion 100 have an angle of 90 degrees. The rotor 20 includes a magnetic pole 400, which includes an arc-shaped outer wall 420 and an inner wall 410. The radii R of the inner wall 410 and the outer wall 420 are equal. The outer wall 420 is close to the stator core 10, and the inner wall 410 is close to the center of the rotor 20.

[0047] Understandably, the rotor 20 is coaxially arranged with the stator core 10 and is fitted inside the stator core 10, and the magnetic poles 400 of the rotor 20 cooperate with the stator teeth 100. It should be noted that the outer wall 420 of the magnetic pole 400 is close to the stator core 10 and cooperates with the stator teeth 100, and the gap between the two is an air gap.

[0048] A toothed shoe portion 120 is located at one end of the connecting portion 110 and near the magnetic pole 400 of the rotor 20, and the toothed shoe portion 120 is integrally formed with the connecting portion 110. In a specific implementation, toothed shoe portions 120 are provided on both sides of the connecting portion 110, and the two toothed shoe portions 120 protrude from the sidewall of the connecting portion 110. A chamfered surface 121 is provided on the side of the toothed shoe portion 120 near the magnetic pole 400, and the chamfered surface 121 forms an angle of 90 degrees with the center line of the stator core 10. (Reference) Figure 2 As shown, the centerline O1 extends radially along the stator core 10. One end of the cut surface 121 connects to the end face of the connecting portion 110. The cut surface 121 is perpendicular to the centerline O1 of the stator tooth portion 100. It can be understood that in the specific implementation, O1 is consistent with the radial direction of the stator core 10, that is, the cut surface 121 is perpendicular to the inner diameter of the stator core 10. It should be noted that the stator tooth portion 100 is symmetrical about the centerline O1. The tooth shoe portion 120 also includes an inclined surface connected to the connecting portion 110 and a side surface connecting the inclined surface and the cut surface 121. The angle between the inclined surface and the connecting portion 110 is an obtuse angle, and the side surface connects the inclined surface and the cut surface 121 respectively.

[0049] In this embodiment, the distance between the edges of the two cut surfaces 121 facing each other is S, and the extension distance of the cut surfaces 121 in the direction perpendicular to the inner diameter of the stator core 10 is L, where L + L = 1 / 2S. (Reference) Figure 2 As shown, the distance between the two cut surfaces 121 at their closest ends is S. The extension distance L of the cut surface 121 in the direction perpendicular to the inner diameter of the stator core 10 and in the direction perpendicular to the axis of the stator core 10 is L+L=1 / 2S. Together with the magnetic poles 400 of the same radius as the inner wall 410 and the outer wall 420, the cogging torque of the motor can reach the minimum value.

[0050] This utility model's technical solution reduces cogging torque by optimizing the structure of the stator core 10. Specifically, the tooth shoe portion 120 of the stator core 10 has a cleaved surface 121 on the side facing the rotor 20. The angle between the cleaved surface 121 and the center line of the stator tooth portion 100 is 90 degrees. The distance between the edges of the two cleaved surfaces 121 facing each other is S. In the direction perpendicular to the inner diameter of the stator core 10, the extension distance of the cleaved surface 121 is L, where L + L = 1 / 2S. Thus, by optimizing the structure of the stator core 10, the complexity of motor magnetic circuit optimization is simplified, R&D efficiency is improved, and customer needs can be responded to quickly. Combined with the equal-radius magnetic pole 400 structure, the cogging torque of the motor is reduced, thereby reducing torque fluctuation, vibration, and noise, improving system control accuracy, reducing cogging torque and noise without affecting motor performance, reducing no-load back EMF distortion rate, and improving waveform sinusoidality. (Reference) Figures 9 to 12 As shown.

[0051] In one embodiment, the inner wall 410 and outer wall 420 of the magnetic pole 400 have equal radii, which improves material utilization and reduces wire cutting costs, thereby reducing the cost of the magnetic pole 400. The inner wall 410 and outer wall 420 of the magnetic pole 400 are arranged opposite each other, and their radii are equal. This facilitates the cutting of permanent magnet material to form the magnetic pole 400, improves material utilization, and reduces wire cutting processing costs. (See reference...) Figure 3 As shown.

[0052] In one embodiment, one end of the connecting portion 110 is provided with an inner arc surface 111, and the two ends of the inner arc surface 111 are respectively connected to two cut surfaces 121. In another embodiment, one end of the connecting portion 110 consists of two intersecting planes, and the intersection of the two planes is located at the center line of the stator tooth portion 100.

[0053] In one embodiment, the stator core 10 further includes a stator yoke 200, which is connected to one end of the connecting portion 110 away from the toothed shoe portion 120. The stator yoke 200 and the connecting portion 110 define a receiving space 310 for accommodating a coil.

[0054] In the specific implementation process, the two ends of the stator yoke 200 extend in the circumferential direction and extend to both sides of the connecting part 110, so that the part of the stator yoke 200 extending circumferentially to the connecting part 110 and the connecting part 110 form a receiving space 310. It can be understood that the stator core 10 coil is wound around the connecting part 110 and located in the receiving space 310.

[0055] Furthermore, the stator yoke 200 and the stator tooth 100 are integrally formed and define a stator unit 11. Multiple stator units 11 are provided, and the multiple stator units 11 are sequentially spliced ​​along the circumferential direction to form a stator core 10. Furthermore, the receiving spaces 310 of two adjacent stator units 11 are arranged opposite each other to form a receiving cavity 300.

[0056] In specific implementation, the stator unit 11 includes an integrally formed stator yoke 200 and a stator tooth 100. The two ends of the stator yoke 200 are respectively connected to the stator yokes 200 of adjacent stator units 11. Multiple stator units 11 are then spliced ​​to form the stator core 10, and two adjacent stator units 11 form a receiving cavity 300 to accommodate the stator core 10 coil. Specifically, the stator yoke 200 has a protrusion 220 at one end and a recess 230 at the other end in the circumferential direction, and the protrusion 220 and recess 230 of adjacent stator units 11 cooperate with each other. The stator units 11 are spliced ​​together through the cooperation of the protrusion 220 and recess 230, which serves as a limiting function and improves the stability of the splicing.

[0057] In one embodiment, a limiting groove 210 is provided on the side of the stator yoke 200 opposite to the connecting portion 110. In specific implementation, the limiting groove 210 is used to engage with the outer shell of the stator core 10 to play a positioning role and improve the stability of the stator core 10.

[0058] In one embodiment, the rotor 20 further includes a rotor body 500, and multiple magnetic poles 400 are provided and are evenly arranged on the outer wall 420 of the rotor body 500 along the circumferential direction of the rotor body 500, and the inner wall 410 of the magnetic poles 400 is attached to and connected to the rotor body 500.

[0059] In the specific implementation process, the magnetic pole 400 is fixedly attached to the outer wall 420 of the rotor body 500 along the circumferential direction of the rotor body 500 and cooperates with the stator teeth 100.

[0060] In one embodiment, the magnetic pole 400 further includes connecting walls 430, with each end of the outer wall 420 connected to a connecting wall 430, and the two connecting walls 430 are arranged parallel to each other. The connecting walls 430 are also connected to the inner wall 410. Specifically, refer to... Figure 3 As shown, the connecting wall 430 extends vertically, and the two connecting walls 430 are arranged in parallel to facilitate the cutting of the permanent magnet material and improve the utilization rate of the permanent magnet material. In addition, the outer wall 420 and the inner wall 410 of the magnetic pole 400 have the same radius, and the two connecting walls 430 are parallel, making the magnetic pole 400 tile-shaped. The thickness of the magnetic pole 400 is the distance between the inner wall 410 and the outer wall 420, which is the distance H between the centers of the inner wall 410 and the outer wall 420.

[0061] This invention reduces cogging torque by employing magnetic poles 400 of equal radius and optimizing the structure of the stator teeth 100, as detailed below:

[0062] Comparison of cogging torque:

[0063] For a motor with 400mm equal-radius tile-shaped magnetic poles and a 10mm stator core with an arc-shaped inner circle, the air gap value is 0.4mm. This was obtained through finite element simulation, as shown in the attached figure. Figure 5 The cogging torque diagram shown is from... Figure 5 As can be seen, the peak-to-peak value of the cogging torque is 21.86 mN·m.

[0064] For motors with equal-radius tile-shaped magnetic poles (400mm) and a cut surface (121) on the inner circle of the stator core (10), the minimum air gap is 0.4mm, and the air gap at the end of the cut surface (121) is 0.671mm; the results obtained through finite element simulation are shown in the attached figure. Figure 6 The cogging torque diagram shown is from... Figure 6 As can be seen, the peak cogging torque is 5.78 m N·m.

[0065] (21.86-5.78) / 21.86*100%=73.56%, thus the cogging torque of the motor with the inner circle cut surface 121 is reduced by 73.56% compared with the cogging torque of the motor with the circular arc surface.

[0066] Torque ripple analysis:

[0067] Both are 400-degree tile-shaped magnetic poles with equal radii, and the results obtained through finite element simulation are shown in the attached figure. Figure 7 The torque ripple diagram shown is from Figure 7 As can be seen from the data, the inner circle of the stator core 10 is an arc surface, and the motor torque pulsation value is 0.0404 N·m.

[0068] Both are 400-degree tile-shaped magnetic poles with equal radii, and the results obtained through finite element simulation are shown in the attached figure. Figure 8 The torque ripple diagram shown is from Figure 8 As can be seen from the data, the motor torque pulsation value of the inner circle of the stator core 10 with the cut surface 121 is 0.0147 N·m.

[0069] (0.0404-0.0147) / 0.0404*100%=63.61%, thus the motor torque ripple value of the stator core 10 with the cut surface 121 is reduced by 73.56% compared with the motor cogging torque of the stator core 10 with the inner circle being an arc surface.

[0070] No-load back EMF FFT distortion rate:

[0071] Both are 400-degree tile-shaped magnetic poles with equal radii, and the results obtained through finite element simulation are shown in the attached figure. Figure 11 The no-load back EMF FFT shown is from Figure 11 As can be seen and calculated, the no-load back EMF distortion rate of the motor with the inner circle of the stator core 10 being an arc surface is 1.06%.

[0072] Both are 400-degree tile-shaped magnetic poles with equal radii, and the results obtained through finite element simulation are shown in the attached figure. Figure 12 The no-load back EMF FFT shown is from Figure 12 As can be seen and calculated, the no-load back EMF distortion rate of the motor with the cut plane 121 on the inner circle of the stator core 10 is 0.46%.

[0073] (1.06-0.46) / 1.06x100%=56.6%, thus the no-load back EMF distortion rate of the motor with the cut surface 121 on the inner circle of the stator core 10 is reduced by 56.6% compared with the cogging torque of the motor with the inner circle of the stator core 10 being an arc surface.

[0074] This invention achieves the effect of a conventional core structure and unequal thickness magnetic poles 400 by changing the configuration of the stator core 10 and combining it with equal radius tile-shaped magnetic poles 400, and the cost of magnetic poles 400 is relatively reduced.

[0075] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the inventive concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A rotor and stator assembly, characterized in that, It includes a stator core and a rotor, wherein the rotor is coaxially mounted inside the stator core, wherein, The stator core includes: The stator tooth section includes a connecting section and a tooth shoe section. The tooth shoe sections are respectively provided on both sides of the connecting section, and the two tooth shoe sections are symmetrically arranged about the center line of the stator tooth section. The tooth shoe section has a cutting plane on the side facing the rotor. The angle between the cutting plane and the center line of the stator tooth section is 90 degrees. The distance between the edges of the two cutting planes facing each other is S. In the direction perpendicular to the inner diameter of the stator core, the extension distance of the cutting plane is L, and L+L=1 / 2S; The rotor includes: The magnetic pole includes an outer wall and an inner wall arranged in an arc shape, the outer wall being close to the stator core and the inner wall being close to the rotor center.

2. The rotor and stator assembly as claimed in claim 1, characterized in that, The inner and outer walls of the magnetic poles have equal radii.

3. The rotor and stator assembly as claimed in claim 1, characterized in that, One end of the connecting part is provided with an inner arc surface, and the two ends of the inner arc surface are respectively connected to the two cut surfaces.

4. The rotor and stator assembly as claimed in claim 1, characterized in that, The stator core also includes a stator yoke, which is connected to the end of the connecting portion away from the toothed shoe portion. The stator yoke and the connecting portion define a receiving space for accommodating the coil.

5. The rotor and stator assembly as claimed in claim 4, characterized in that, The stator yoke and the stator teeth are integrally formed and defined to form a stator unit. Multiple stator units are provided, and multiple stator units are sequentially spliced ​​together along the circumferential direction to form the stator core.

6. The rotor and stator assembly as claimed in claim 5, characterized in that, The accommodating spaces of two adjacent stator units are arranged opposite each other to form an accommodating cavity.

7. The rotor and stator assembly as claimed in claim 4, characterized in that, The stator yoke is provided with a limiting groove on the side opposite to the connecting part.

8. The rotor and stator assembly as claimed in claim 4, characterized in that, The stator yoke has a protrusion at one end and a recess at the other end in the circumferential direction, and the protrusion and the recess of the adjacent stator unit cooperate with each other.

9. The rotor and stator assembly as claimed in claim 1, characterized in that, The rotor also includes a rotor body, and multiple magnetic poles are provided and are evenly arranged on the outer wall of the rotor body in sequence along the circumferential direction of the rotor body, and the inner wall of the magnetic poles is in close contact with the rotor body.

10. The rotor and stator assembly as claimed in claim 2, characterized in that, The magnetic pole also includes a connecting wall, with the two ends of the outer wall respectively connected to the connecting wall, and the two connecting walls are arranged parallel to each other, and the connecting wall is also connected to the inner wall.

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