Electric motor rotor and axial electric motor

Abstract

The application relates to a motor rotor, comprising a rotor support and a plurality of magnet units, the rotor support comprising a support ring, the support ring having a first ring surface and a second ring surface in the thickness direction, the plurality of magnet units being arranged at intervals along the circumferential direction of the first ring surface, the first ring surface being provided with a first annular taper surface, each magnet unit having a first magnetic surface and a second magnetic surface in the thickness direction, the first magnetic surface being provided with a first magnetic taper surface, the first magnetic taper surface being matched with the first annular taper surface, wherein the thickness of the support ring at the first annular taper surface part gradually decreases in the direction from the ring center to the ring outer edge, and the thickness of the magnet unit at the first magnetic taper surface part gradually increases in the direction from the ring center to the ring outer edge. The application also relates to an axial motor. The use amount of permanent magnet material is reduced, and cost is saved.

Description

Technical Field

[0001] This application relates to the field of motor technology, and in particular to a motor rotor and an axial motor. Background Technology

[0002] Axial motors are widely used in new energy vehicle drives, industrial servo systems, and home appliances due to their compact structure, high power density, and stable torque output. In existing axial motors, the rotor typically uses multiple fan-shaped magnet units of equal thickness, evenly arranged circumferentially on the rotor support, forming an air gap magnetic circuit opposite to the stator teeth. While this structure facilitates manufacturing and assembly, it reveals significant magnetic circuit design flaws during actual operation: the small cross-sectional area of ​​the teeth in the inner diameter region of the stator core results in high magnetic reluctance in this area. Under no-load or load conditions, magnetic flux concentrates through this narrow path, causing a sharp increase in local magnetic density and leading to severe magnetic saturation. Magnetic saturation not only limits the effective utilization of permanent magnet properties and reduces material utilization, but also increases motor output torque fluctuations, reduces efficiency, and may induce vibration and noise, affecting operational stability. Furthermore, to compensate for the performance losses caused by magnetic saturation, the amount of permanent magnets used often needs to be increased, further increasing material costs.

[0003] Therefore, there is a need for a motor rotor that can reduce material costs. Summary of the Invention

[0004] The purpose of this application is to provide a motor rotor that solves the problem of high material cost of motor rotors in the prior art.

[0005] To achieve the above objectives, this application provides a motor rotor, comprising: a rotor support and a plurality of magnet units. The rotor support includes a support ring, the support ring having a first annular surface and a second annular surface along the thickness direction. The plurality of magnet units are arranged at intervals along the circumferential direction of the first annular surface. The first annular surface is provided with a first annular conical surface. Each magnet unit has a first magnetic surface and a second magnetic surface along the thickness direction. The first magnetic surface is provided with a first magnetic inclined surface, which is in contact with the first annular conical surface. The thickness of the support ring in the portion of the first annular conical surface gradually decreases along the direction from the center of the ring to the outer edge of the ring, and the thickness of the magnet units in the portion of the first magnetic inclined surface gradually increases along the direction from the center of the ring to the outer edge of the ring.

[0006] Wherein, the thickness h of the magnet unit in the first magnetic inclined surface portion m The design formula is: Among them, B tLet be the magnetic flux density of the teeth of the motor stator core, D be the armature diameter of the motor stator core, b be the slot width of the motor stator core, and δ be the air gap width between the surfaces of the magnetic units of the motor stator core and the motor rotor. mg u is the maximum value of the air gap magnetic flux density. r Where Z is the relative permeability, Z is the number of slots in the motor stator, and B is the relative permeability. r The remanence of the permanent magnet material in the magnet unit is expressed in mm, and the magnetic flux density is expressed in T.

[0007] Wherein, the second annular surface is a ring-shaped plane, the second magnetic surface is a magnetic plane, and the second annular surface is parallel to the second magnetic surface.

[0008] The rotor support further includes a rotating ring, which is located on the outer circumference of the rotating ring. The rotating ring has a first mounting plane and a second mounting plane that are arranged opposite to each other and are parallel to each other.

[0009] Wherein, the first mounting plane and the second magnetic surface are located in the same plane; the second mounting plane and the first annular surface are located in the same plane.

[0010] The rotating ring and the support ring are integrally formed.

[0011] The gaps between adjacent magnet units are filled with a filling material.

[0012] The magnet unit has a fan-shaped structure.

[0013] When the first magnetic inclined plane is inclined along a straight line, the angle α between the second magnetic surface and the first magnetic inclined plane is set to be between 10° and 30°. Another object of this application is an axial motor, including a motor stator and the motor rotor described above.

[0014] Compared with the prior art, the embodiments of this application have at least the following beneficial effects: by adopting a magnet unit with unequal thickness from the inner end to the outer end of the magnet, the amount of permanent magnet material used is reduced, saving costs. At the same time, it effectively improves the motor's operational stability and electromagnetic performance consistency. Attached Figure Description

[0015] Figure 1 A perspective view of an electric motor rotor according to a preferred embodiment of the present application is shown.

[0016] Figure 2 A top view of an electric motor rotor according to a preferred embodiment of the present application is shown.

[0017] Figure 3 It shows Figure 2 Sectional view of AA.

[0018] Figure 4 A cross-sectional view of a rotor support for an electric motor rotor according to a preferred embodiment of the present application is shown.

[0019] Figure 5 A cross-sectional view of the magnet unit of an electric motor rotor according to a preferred embodiment of the present application is shown.

[0020] Figure 6 A front view of an axial motor according to a preferred embodiment of this application is shown.

[0021] Figure 7 A cross-sectional view of an axial motor according to a preferred embodiment of this application is shown. Figure 6 (Middle edge BB).

[0022] Figure 8 A structural diagram of an axial motor according to a preferred embodiment of the present application, after being unfolded in the radial direction, is shown.

[0023] Figure 9 A cross-sectional view of an electric motor rotor according to another preferred embodiment of this application is shown.

[0024] Figure 10 A cross-sectional view of a rotor support for an electric motor rotor according to another preferred embodiment of this application is shown.

[0025] Figure 11 A cross-sectional view of the magnet unit of an electric motor rotor according to another preferred embodiment of this application is shown.

[0026] Figure 12 A perspective view of an electric motor rotor according to the prior art is shown.

[0027] Figure label: 1. Motor rotor; 2. Motor stator; 10. Rotor support; 11. Rotating ring; 111. First mounting plane; 112. Second mounting plane; 12. Support ring; 121. First annular surface; 1211. First annular conical surface; 1212. First annular plane; 122. Second annular surface; 20. Magnetic unit; 21. First magnetic surface; 211. First magnetic inclined plane; 212. Second magnetic plane; 22. Second magnetic surface; O, the center of the ring. Detailed Implementation

[0028] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not all of them.

[0029] This application defines certain directional terms. Unless otherwise stated, the directional terms used, such as "up," "down," "left," "right," "inner," and "outer," are used for ease of understanding and therefore do not constitute a limitation on the scope of protection of this application.

[0030] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0031] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] Example 1 Reference Figures 1 to 5 As shown, a preferred embodiment of an electric motor rotor is illustrated. The electric motor rotor includes a rotor support 10 and a plurality of magnet units 20. Figure 1 As shown, there are eight magnet units 20, and each magnet unit 20 is made of permanent magnet material. In other embodiments, there may be six, ten, or twelve magnet units 20.

[0033] like Figures 2 to 5As shown, the rotor support 10 includes a support ring 12, which has a first annular surface 121 and a second annular surface 122 along the thickness direction. Multiple magnet units 20 are evenly spaced along the circumference of the first annular surface 121. The first annular surface 121 has a first annular conical surface 1211. Each magnet unit 20 has a first magnetic surface 21 and a second magnetic surface 22 along the thickness direction. The first magnetic surface 21 has a first magnetic inclined surface 211, which fits against the first annular conical surface 1211. The thickness of the support ring 12 at the first annular conical surface 1211 gradually decreases from the center O of the ring towards the outer edge, while the thickness of the magnet unit 20 at the first magnetic inclined surface 211 gradually increases from the center O of the ring towards the outer edge. Figure 3 As shown, the support ring 12 has an overall structure that is thicker inside and thinner outside, while the magnet unit 20 has a structure that is thinner inside and thicker outside.

[0034] In this application, the magnet unit 20 gradually increases in size from the center of the support ring 12 towards the outer edge of the ring, optimizing the magnetic circuit distribution and significantly improving the magnetic concentration phenomenon in the inner diameter region of the motor stator core. Compared with the traditional solution using magnet units of uniform thickness, this significantly improves the utilization rate of permanent magnet materials. Under the premise of ensuring the performance of the magnet unit, the amount of permanent magnet material used can be reduced, thereby lowering costs.

[0035] Reference Figures 6 to 8 As shown, an axial motor is illustrated, comprising a stator 2 and a rotor 1, wherein the rotor 1 is the aforementioned rotor. The stator 2 and rotor 1 are spaced apart along the same rotation axis, which passes through the annular center O of the stator 1 and rotor 2. The distance between the iron core of the stator 2 and the surface of the magnet unit 20 of the rotor 1 is the air gap width δ. The number of slots in the stator is Z, wherein in this embodiment, Z=12. The slot pitch t, ​​tooth width c, slot width b of the stator iron core, and armature diameter D of the stator iron core are also shown. Figure 2 As shown, D1 and D2 are the inner and outer diameters of the first magnetic inclined surface 211 of the magnet unit 20 of the motor rotor 2, corresponding to the motor stator 2. The thickness design of the magnet unit 20 in the first magnetic inclined surface 211 is based on the parameters of the motor stator core corresponding to the motor rotor, the air gap width, and the remanence coefficient of the permanent magnet material. The design formula is as follows: ...Formula ① t=π D / Z……Formula ② c=π D / Zb……Formula ③ B t c=B mg t……Formula ④ Combining equations ① to ④ above, the thickness h of the magnet unit 20 in the first magnetic inclined surface 211 is calculated. m The design formula is: Among them, B t Let be the magnetic flux density of the teeth of the motor stator core, D be the armature diameter of the motor stator core, b be the slot width of the motor stator core, and δ be the air gap width between the surfaces of the magnetic units of the motor stator core and the motor rotor. mg u is the maximum value of the air gap magnetic flux density. r Where Z is the relative permeability, t is the number of slots in the motor stator, c is the slot pitch in the motor stator, and B is the tooth width in the motor stator. r The remanence of the permanent magnet material in the magnet unit is expressed in mm, and the magnetic flux density is expressed in T.

[0036] According to the above formula, as the value of D increases, h m The thickness gradually increases, meaning the thickness of the inner end of the first magnetic inclined surface 211 of the magnet unit 20 is less than the thickness of the outer end. During the design process, to ensure that the first magnetic inclined surface 211 slopes linearly from the inside to the outside, h is calculated using D1 and D2 respectively. m1 and h m2 After determining the thickness at both ends, a straight generatrix is ​​obtained by connecting the two ends with a straight line. The generatrix is ​​then rotated around the center of rotation to obtain a first magnetic inclined plane 211 with a straight inclination. To make the first magnetic inclined plane 211 inclined along a curve from the inside to the outside, D3…D… can be added between the two points, based on D1 and D2. N Calculate h m3 ...h mN The curve generatrix is ​​obtained by connecting them sequentially, and the curve generatrix is ​​rotated around the rotation axis to obtain the first magnetic inclined surface 211 with the curve tilting. Correspondingly, the first annular conical surface 1211 of the support ring 12 is designed to match the first magnetic inclined surface 211 of the magnet unit, and can also be obtained by rotating the generatrix around the rotation axis.

[0037] like Figure 3 As shown, the second annular surface 122 of the support ring 12 is an annular plane, and the second magnetic surface 22 is a magnetic plane. The second annular surface 122 and the second magnetic surface 22 are parallel. This effectively improves the operational stability and electromagnetic performance consistency of the axial motor. It also makes the air gap side form a plane as a whole, while optimizing the magnetic circuit distribution and significantly improving the phenomenon of magnetic concentration.

[0038] like Figures 1 to 5As shown, the rotor support 10 also includes a rotating ring 11, and a support ring 12 is located outside the circumference of the rotating ring 11. The rotating ring 11 and the support ring 12 have the same center. The rotating ring 11 has a first mounting plane 111 and a second mounting plane 112 that are arranged opposite to each other and are parallel to each other. The rotating ring 11 is used to mount the output shaft of the axial motor.

[0039] like Figure 5 As shown (the dashed line is not the structure of the magnetic unit 20 itself), when the first magnetic inclined surface 211 is inclined along a straight line, the angle α between the second magnetic surface 22 and the first magnetic inclined surface 211 is set to 10° to 30°.

[0040] like Figure 3 As shown, the first mounting plane 111 and the second magnetic surface 22 are located in the same plane, and the second mounting plane 112 and the second annular surface 122 are located in the same plane, thereby ensuring the consistency of the assembly reference of the entire motor rotor in the axial direction and enhancing the rotational coordination performance. The rotating ring 11 and the support ring 12 adopt an integral molding structure, for example, by casting, 3D printing and / or machining to improve structural rigidity and assembly accuracy.

[0041] like Figure 1 As shown, a gap is left between adjacent magnet units 20. In some embodiments, this gap is filled with a filler (not shown) such that the surface of the filler is in the same plane as the first mounting plane 111 and the second magnetic surface 22. This further makes the air gap side as a whole planar surface, optimizes the magnetic circuit distribution, and significantly improves the phenomenon of magnetic concentration.

[0042] The magnet unit 20 can closely fit the first annular conical surface 1211 of the support ring 12, while optimizing the magnetic circuit distribution. Specifically, in some embodiments, the inner end thickness of the magnet unit 20 is 2 to 3 mm, and the outer end thickness is 8 to 12 mm. This thickness gradient configuration effectively adjusts the radial magnetic flux density distribution of the stator core, avoiding magnetic saturation in the inner diameter region of the stator, and making the magnetic flux density distribution more uniform. This reduces the amount of permanent magnet material used while maintaining a high back EMF output. By designing the magnets to have unequal thickness shapes and cooperating with the support ring with a reverse taper, this rotor structure achieves efficient utilization of permanent magnet materials, significantly reduces material costs while ensuring the electromagnetic performance of the motor, and improves the overall operating performance of the axial motor.

[0043] Example 2 Reference Figures 9 to 11 As shown, another preferred embodiment of an electric motor rotor is illustrated. The electric motor rotor includes a rotor support 10 and a plurality of magnet units 20. The number of magnet units 20 is 6, 8, 10, or 12.

[0044] like Figures 9 to 11As shown, the rotor support 10 includes a support ring 12, which has a first annular surface 121 and a second annular surface 122 along the thickness direction. Multiple magnet units 20 are evenly spaced along the circumference of the first annular surface 121. The first annular surface 121 has a first annular conical surface 1211 and a first annular plane 1212. Each magnet unit 20 has a first magnetic surface 21 and a second magnetic surface 22 along the thickness direction. The first magnetic surface 21 has a first magnetic inclined surface 211 and a first magnetic plane 212. The first magnetic inclined surface 211 is in contact with the first annular conical surface 1211, and the first annular plane 1212 is in contact with the first magnetic plane 212. The thickness of the support ring 12 in the portion of the first annular conical surface 1211 gradually decreases along the direction from the center O of the ring to the outer edge of the ring, while the thickness of the magnet unit 20 in the portion of the first magnetic inclined surface 211 gradually increases along the direction from the center O of the ring to the outer edge of the ring. The support ring 12 has an overall structure that is thicker on the inside and thinner on the outside, while the magnet unit 20 has a structure that is thinner on the inside and thicker on the outside. In this embodiment, the thickness h of the magnet unit 20 in the first magnetic inclined surface 211 is... m The design formula can also be: For the first magnetic plane 212 portion, the thickness value of the magnet unit 20 is no longer based on h. m The design formula.

[0045] In this embodiment, each magnet unit 20 also has a fan-shaped structure.

[0046] The main difference between Embodiment 2 and Embodiment 1 is that, in Embodiment 1, the first annular conical surface 1211 extends from the inner end to the outer end of the support ring 12, while in Embodiment 2, the first annular conical surface 1211 occupies only a part of the first annular surface 121, with the other part being the first annular plane 1212. Other configurations in Embodiment 2 are the same as in Embodiment 1 and will not be repeated here.

[0047] Taking the design of an axial motor as an example, the parameters of the motor are rated power of 750W, rated speed of 6000rpm, power supply voltage of 200VAC, outer diameter of the motor stator of 100mm, inner diameter of the motor stator of 56mm, and motor rotor designed according to the stator. Among them, the outer diameter of the bracket ring 12 of the rotor bracket 10 is 100mm, and the inner diameter of the bracket ring 12 of the rotor bracket 10 is 56mm.

[0048] When designing the motor, based on the simulation experiment, Table 1 shows that when the thickness of the magnet unit is 6mm, as the armature diameter D of the motor stator core increases, the magnetic flux density of the stator teeth changes. The data shows that the magnetic flux density decreases. The data of magnet units with different thicknesses at two diameters of 56mm (the thickness of the magnet unit in the last row is 2mm) can explain that the reduced thickness magnetic flux density is within the expected design target.

[0049] Table 1:

[0050] Table 1 shows that when the slot width b between magnet units is 10mm, the pole arc coefficient of the magnet unit is 0.9, and the thickness of the magnet unit is 6mm, the magnetic flux density decreases as the armature diameter D of the motor stator core increases. However, as shown in the last row of Table 1, when the armature diameter D of the motor stator core is 56mm, choosing a magnet unit thickness of 2mm can avoid magnetic saturation at the 56mm diameter, and the unloaded stator tooth magnetic flux density of 1.4T is a reasonable design value at this point.

[0051] To verify whether the conclusions in the table above are consistent, another set of experiments was designed, in which the polar arc coefficient was adjusted to 0.7. The experimental results are shown in Table 2.

[0052] Table 2:

[0053] The difference between Table 2 and Table 1 is that in Table 2, when the magnet unit pole arc coefficient is 0.7 and the magnet unit thickness is 6mm, the stator tooth magnetic flux density values ​​for different diameters are shown in the table. It can be seen from the table that the magnetic flux density values ​​decrease progressively, indicating a consistent trend. Comparing Table 1, the stator tooth magnetic flux density is affected by the magnet unit pole arc coefficient. To obtain greater magnetic performance, the principle is that the larger the pole arc coefficient of the magnet unit, the better, but magnetic leakage of the magnet unit must be considered.

[0054] When the armature diameter D of the motor stator core is 100, and with the same slot width b and tooth width c, the change in back electromotive force V as the magnet unit increases is shown in Table 3: Table 3:

[0055] Table 3 shows that when the armature diameter D of the motor stator core is 100 mm, under the same slot width b, tooth width c, and pole arc coefficient, the change in back electromotive force increases with increasing thickness, and the rate of increase decreases. Furthermore, when the magnet unit thickness exceeds 8 mm, the increase becomes negligible. Therefore, for this motor, a maximum magnet unit thickness of 8 mm is appropriate.

[0056] To verify whether this view holds true at larger sizes, the back potential at a diameter of 153 mm was also tested.

[0057] Table 4

[0058] As can be seen from the data in Table 4, at a diameter of 153 mm, increasing the thickness of the magnet unit results in a negligible increase in back potential after the magnet unit thickness reaches 8 mm.

[0059] In summary, the thickness of the magnet unit is within a reasonable design range of 2mm ≤ h ≤ 8mm.

[0060] According to the motor rotor of this application, the inner end thickness of the first magnetic inclined surface 211 of the magnet unit 20 is 2mm and the outer end thickness is 8mm.

[0061] Table 5 lists the differences between the volume of a magnet unit and its back electromotive force.

[0062] Table 5:

[0063] like Figure 12 As shown, a prior art motor rotor is illustrated, where the magnet units are of uniform thickness, meaning the thickness of each magnet unit is 8mm from the inside out; Table 5 shows an unequal thickness magnet unit scheme 1 as follows... Figures 1 to 5 As shown, in scheme 1 of unequal thickness magnet unit, the inner end thickness of magnet unit 20 is 2mm and the outer end thickness is 8mm; as Figures 9 to 11 As shown, in unequal thickness magnet unit scheme 2, the inner end thickness is 2mm, and the magnet unit thickness at a diameter of 92mm is 8mm, with the outer end also having a thickness of 8mm. A comparison of the volume usage and back EMF of the three schemes is presented. Table 5 shows that the material waste problem can be solved by optimizing the thickness of the magnet unit. Unequal thickness magnet unit scheme 1 and scheme 2 save 35% and 28% of material, respectively. Furthermore, the back EMF of scheme 1 decreases by only 9.1% compared to the equal thickness magnet unit scheme, while the back EMF of scheme 2 decreases by only 7.6% compared to the equal thickness magnet unit scheme. These data demonstrate that using unequal thickness magnet unit schemes can significantly improve the utilization rate of permanent magnet materials.

[0064] Reference Figures 6 to 8 As shown, this application also provides an axial motor, which includes a motor stator 2 and a motor rotor 1.

[0065] Although this application has been described in detail above with general descriptions, specific embodiments, and experiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of this application fall within the scope of protection claimed in this application.

Claims

1. A motor rotor, characterized in that, include: The rotor support includes a support ring having a first annular surface and a second annular surface along its thickness direction. The multiple magnet units are spaced apart along the circumferential direction of the first annular surface. The first annular surface has a first annular conical surface. Each magnet unit has a first magnetic surface and a second magnetic surface along its thickness direction. The first magnetic surface has a first magnetic inclined surface that fits against the first annular conical surface. The thickness of the support ring at the first annular conical surface gradually decreases from the center of the ring towards its outer edge, while the thickness of each magnet unit at the first magnetic inclined surface gradually increases from the center of the ring towards its outer edge.

2. The motor rotor according to claim 1, characterized in that, The magnet unit has a thickness h of the first magnetic slope portion m The design formula is: Among them, B t Let be the magnetic flux density of the teeth of the motor stator core, D be the armature diameter of the motor stator core, b be the slot width of the motor stator core, and δ be the air gap width between the surfaces of the magnetic units of the motor stator core and the motor rotor. mg u is the maximum value of the air gap magnetic flux density. r Where Z is the relative permeability, Z is the number of slots in the motor stator, and B is the relative permeability. r The remanence of the permanent magnet material in the magnet unit is expressed in mm, and the magnetic flux density is expressed in T.

3. The motor rotor according to any one of claims 1 to 2, characterized in that, The second toroidal surface is a ring-shaped plane, the second magnetic surface is a magnetic plane, and the second toroidal surface is parallel to the second magnetic surface.

4. The motor rotor according to claim 3, characterized in that, The rotor support also includes a rotating ring, the support ring being disposed on the outer circumference of the rotating ring, the rotating ring having a first mounting plane and a second mounting plane that are arranged opposite to each other and parallel to each other.

5. The motor rotor according to claim 4, characterized in that, The first mounting plane and the second magnetic surface are located in the same plane; the second mounting plane and the first annular surface are located in the same plane.

6. The motor rotor according to claim 4, characterized in that, The rotating ring and the support ring are integrally formed.

7. The motor rotor according to claim 3, characterized in that, The gaps between adjacent magnet units are filled with a filling material.

8. The motor rotor according to claim 3, characterized in that, The magnet unit has a fan-shaped structure.

9. The motor rotor according to claim 3, characterized in that, When the first magnetic inclined plane is inclined along a straight line, the angle α between the second magnetic surface and the first magnetic inclined plane is set to be between 10° and 30°.

10. An axial motor, characterized in that, It includes a motor stator and a motor rotor as described in any one of claims 1 to 9.

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