Motor rotor magnetic pole arrangement structure

Abstract

The utility model discloses a motor rotor magnetic pole arrangement structure, comprising a rotor hub, the periphery of which is fixedly sleeved with a single-layer rotor iron core; n magnetic poles are distributed on the circumference of the rotor core at intervals; the N magnetic poles are equally divided into m groups, each group comprises k magnetic poles, N is equal to m * k, m is larger than or equal to 2, and k is larger than or equal to 4; the interval angle alpha of the magnetic poles in the group is 360 degrees / k; a phase difference angle beta is arranged between every two adjacent groups, beta = d * 360 degrees / N, and the value range of d is larger than or equal to 0.8 and smaller than or equal to 0.95; according to the utility model, the layered structure of the traditional skewed pole process is abandoned, and the problem of positioning failure caused by interference assembly is avoided, so that the sensitivity to the assembly angle error is reduced, the process tolerance requirement is relaxed, and the production feasibility is obviously improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor manufacturing technical field, concretely relates to a motor rotor magnetic pole arrangement structure. BACKGROUND

[0002] The new energy motor rotor as the core component of energy conversion is usually composed of a rotor hub, a rotor core and a magnetic pole. The rotor hub is directly assembled on the engine crankshaft through interference fit to drive the rotor core and the magnetic pole to rotate, so that the stator coil generates induced electromotive force, and the controller rectifies the induced electromotive force to charge the power battery. However, due to the manufacturing process constraints (such as the square design of the magnetic pole) and the influence of the stator tooth slot effect, the rotor surface magnetic distribution deviates from the ideal sinusoidal waveform, resulting in periodic fluctuation of the torque in the rotation process. Such fluctuation not only reduces the stability of the motor output, but also causes vibration and noise problems, which seriously affect the equipment life and user experience.

[0003] The prior art mainly adopts the inclined pole scheme to suppress the torque fluctuation. The principle is to divide the rotor into layers along the axial direction and stagger a certain angle, and realize overall fluctuation control by offsetting the wave peaks and troughs of the interlayer torque fluctuation. However, this scheme has the following inherent defects:

[0004] Firstly, the effect of the inclined pole is highly dependent on the stagger angle between the layers. Experiments show that an angle deviation of 0.1° will cause the torque fluctuation to increase by 20%. Due to the limitation of the difference between the inner and outer diameters of the rotor, mechanical positioning methods such as spline cannot be used. Therefore, it is difficult to achieve the actual assembly accuracy of ±0.1° only by interference assembly.

[0005] Secondly, the layered structure needs to be assembled multiple times by heat shrinkage, which increases the process complexity and cost, and the batch consistency is poor, resulting in significant differences in vibration and noise performance between products, and some individuals even exceed the standard limit. UTILITY MODEL CONTENTS

[0006] The utility model aims at the problems existing in the prior art, and provides a motor rotor magnetic pole arrangement structure, which discards the layered structure of the traditional inclined pole process and avoids the positioning failure problem caused by interference assembly. Therefore, the sensitivity to assembly angle error is reduced, the process tolerance requirement is relaxed, and the production feasibility is significantly improved.

[0007] To achieve the above-mentioned purpose, the utility model adopts the technical scheme of:

[0008] A motor rotor magnetic pole arrangement structure includes: a rotor hub, on the outer periphery of which a single-layer rotor core is fixedly sleeved; N magnetic poles are distributed circumferentially on the rotor core; the N magnetic poles are divided into m groups, each group including k magnetic poles, and satisfying N=m×k, where m≥2, k≥4; the magnetic pole spacing angle within a group is α=360° / k; a phase difference angle β is set between adjacent groups, and satisfying β=d×360° / N, where the value of d is 0.8≤d≤0.95.

[0009] Furthermore, the rotor core has 24 magnetic poles distributed circumferentially; the 24 magnetic poles are divided into three groups, A, B and C, each group including 8 magnetic poles, and the 8 magnetic poles in each group are evenly distributed at 45° circumferential intervals; the phase difference angle between adjacent groups is set at 13.5°, and they are staggered along the phase difference angle.

[0010] Furthermore, the rotor hub and the rotor core are interference-fitted, and the mating surface is a smooth cylindrical surface without splines.

[0011] Furthermore, the outer circumference of the rotor core is provided with an arc-shaped groove between each pair of adjacent magnetic poles.

[0012] Furthermore, the magnetic poles are square permanent magnets.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] By grouping magnetic poles and setting a specific phase difference angle, the grouping structure disperses torque fluctuation energy into multiple harmonic components, reducing the amplitude of a single frequency component. The phase difference angle β causes the torque fluctuations generated by adjacent groups of magnetic poles to form a specific phase relationship in space and time, resulting in the phase lag or lead of the torque fluctuations of adjacent groups, forming a fluctuation cancellation effect in the time domain. By adjusting the phase difference amplitude by the d value, the fluctuation amplitude of the synthesized torque can be minimized.

[0015] By superimposing and canceling the fluctuation components of multiple magnetic poles, the fluctuation rate of the synthesized torque is reduced. Since the phase difference is achieved through the circumferential arrangement of magnetic poles, the layered structure of the traditional skewed pole process is abandoned, and the positioning failure problem caused by interference assembly is avoided. Therefore, the sensitivity to assembly angle error is reduced, the process tolerance requirements are relaxed, and the production feasibility is significantly improved. Attached Figure Description

[0016] 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 these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the rotor magnetic pole arrangement structure of a motor in one embodiment of this application;

[0018] Figure 2 For this application Figure 1 A schematic diagram of the distribution of a group of magnetic poles;

[0019] Figure 3 This is a schematic diagram of the rotor magnetic pole arrangement structure of a motor in one embodiment of this application;

[0020] In the diagram: 1. Rotor hub; 2. Rotor core; 3. Magnetic pole; 4. Arc-shaped groove. Detailed Implementation

[0021] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0024] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0025] As the core component of energy conversion, the rotor of a new energy motor typically consists of three parts: the rotor hub, the rotor core, and the magnetic poles. The rotor hub is directly mounted to the engine crankshaft via an interference fit, driving the rotor core and magnetic poles to rotate. This induces an electromotive force in the stator coils, which, after rectification by the controller, charges the power battery. However, due to manufacturing constraints (such as the square design of the magnetic poles) and the stator cogging effect, the surface magnetic distribution of the rotor deviates from the ideal sine wave, causing periodic fluctuations in torque during rotation. These fluctuations not only reduce the stability of the motor output but also cause vibration and noise problems, seriously affecting the equipment's lifespan and user experience.

[0026] Existing technologies mainly employ a skewed-pole scheme to suppress torque ripple. The principle is to divide the rotor into layers along the axial direction and stagger them at a certain angle, thereby achieving overall ripple control by canceling out the peaks and troughs of torque ripple between layers. However, this scheme has the following inherent drawbacks:

[0027] First, the skewed pole effect is highly dependent on the interlayer misalignment angle. Experiments show that an angle deviation of 0.1° will lead to a 20% increase in torque fluctuation. Due to the limitation of the rotor's inner and outer diameter difference, mechanical positioning methods such as splines cannot be used. When relying solely on interference fit, the actual assembly accuracy is difficult to achieve the ±0.1° requirement.

[0028] Second, the layered structure requires multiple thermal assembly processes, increasing process complexity and cost. This results in poor batch consistency and significant differences in vibration and noise performance between products, with some individual products even exceeding standard limits.

[0029] To address the above technical issues, such as Figure 1 As shown in the figure, this application provides a motor rotor magnetic pole arrangement structure, including: a rotor hub 1, on the outer periphery of which a single-layer rotor core 2 is fixed; N magnetic poles 3 are distributed circumferentially on the rotor core 2; the N magnetic poles 3 are divided into m groups, each group including k magnetic poles, and satisfying N=m×k, where m≥2, k≥4; the magnetic pole spacing angle α within the group is 360° / k; a phase difference angle β is set between adjacent groups, and satisfying β=d×360° / N, where the value of d is 0.8≤d≤0.95; the value of d is determined by electromagnetic simulation, so that the torque fluctuations of multiple groups of magnetic poles cancel each other out.

[0030] like Figure 2 As shown, Figure 1 A schematic diagram of the distribution of one set of magnetic poles.

[0031] The grouping structure disperses torque ripple energy across multiple harmonic components, reducing the amplitude of a single frequency component. The phase difference angle β causes torque ripples generated by adjacent groups of magnetic poles to form a specific phase relationship in space and time, resulting in phase lag or lead of torque ripples in adjacent groups, creating a time-domain ripple cancellation effect. By adjusting the phase difference amplitude by the d value, the amplitude of the combined torque ripple can be minimized.

[0032] Traditional skewed pole designs are highly dependent on the interlayer misalignment angle for optimal performance. A 0.1° deviation in angle can lead to a 20% increase in torque fluctuation. Furthermore, due to the difference in rotor inner and outer diameters, mechanical positioning methods such as splines cannot be used. When relying solely on interference fit, the actual assembly accuracy is difficult to achieve the ±0.1° requirement. This new design, however, reduces the combined torque fluctuation rate by superimposing and canceling out the fluctuation components of multiple magnetic poles. The phase difference is achieved through the circumferential arrangement of the magnetic poles, eliminating the layered structure of traditional skewed pole processes and avoiding the positioning failure problem caused by interference fit. Therefore, it is less sensitive to assembly angle errors, relaxes process tolerance requirements, and significantly improves production feasibility.

[0033] like Figure 3 As shown, in one embodiment,

[0034] The total number of magnetic poles N = 24, divided into three groups A / B / C, i.e., the number of groups m = 3, and the number of magnetic poles in each group k = 8;

[0035] The pole spacing angle within the group is α = 360° / k = 360° / 8 = 45°;

[0036] The phase difference between adjacent groups β = d × 360° / N = 0.9 × 360° / 24 = 13.5°;

[0037] Electromagnetic simulation verified that when d = 0.9, the 8th torque ripple harmonics of the three magnetic poles A / B / C cancel each other out; the torque ripple rate is reduced to 3.8%, which is approximately the same as the 3.5% ripple rate of the 3-layer skewed pole scheme.

[0038] In one embodiment,

[0039] The total number of magnetic poles N = 18, the number of groups m = 2, and the number of magnetic poles in each group k = 9;

[0040] The pole spacing angle within the group is α = 360° / k = 360° / 9 = 40°;

[0041] The phase difference between adjacent groups β = d × 360° / N = 0.9 × 360° / 18 = 18°;

[0042] Electromagnetic simulation verified that when d = 0.9, the sixth torque ripple harmonics of the two sets of magnetic poles cancel each other out, and the overall torque ripple rate is reduced to 3.2%.

[0043] In one embodiment,

[0044] The total number of magnetic poles N = 30, the number of groups m = 5, and the number of magnetic poles in each group k = 6;

[0045] The pole spacing angle within the group is α = 360° / k = 360° / 6 = 60°;

[0046] The phase difference between adjacent groups is β = d × 360° / N = 0.85 × 360° / 30 = 10.2°.

[0047] Electromagnetic simulation verified that when d = 0.85, the 10th torque ripple harmonics of the 5 magnetic poles cancel each other out, and the overall torque ripple rate is reduced to 4.7%.

[0048] In one embodiment, the rotor hub 1 and the rotor core 2 are interference-fitted, and the mating surface is a smooth cylindrical surface without splines.

[0049] In one embodiment, the outer circumference of the rotor core 2 is provided with an arc-shaped groove 4 between each pair of adjacent magnetic poles 3.

[0050] In one embodiment, the magnetic pole 3 is a square permanent magnet.

[0051] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rotor magnetic pole arrangement structure for an electric motor, characterized in that, include: Rotor hub (1), the outer periphery of which is fixedly fitted with a single layer of rotor core (2); The rotor core (2) has N magnetic poles (3) distributed circumferentially; The N magnetic poles (3) are divided into m groups, each group containing k magnetic poles, and satisfying N = m × k, where m ≥ 2 and k ≥ 4; the pole spacing angle α within the group is 360° / k. A phase difference angle β is set between adjacent groups, and β = d × 360° / N is satisfied, where the value of d is 0.8 ≤ d ≤ 0.

95.

2. The motor rotor magnetic pole arrangement structure according to claim 1, characterized in that, The rotor core (2) has 24 magnetic poles (3) distributed circumferentially; The 24 magnetic poles (3) are divided into three groups: A, B and C. Each group includes 8 magnetic poles (3), and the 8 magnetic poles (3) in each group are evenly distributed at 45° circumferential intervals. The phase difference angle between adjacent groups is set to 13.5°.

3. The motor rotor magnetic pole arrangement structure according to claim 1, characterized in that, The rotor hub (1) and the rotor core (2) are interference fit, and the mating surface is a smooth cylindrical surface without splines.

4. The motor rotor magnetic pole arrangement structure according to claim 1, characterized in that, The outer circumference of the rotor core (2) is provided with an arc-shaped groove (4) between each two adjacent magnetic poles (3).

5. The motor rotor magnetic pole arrangement structure according to claim 1, characterized in that, The magnetic pole (3) is a square permanent magnet.

Images