Permanent magnet hub motor mixed magnetic pole surface-mounted outer rotor
The hybrid magnetic pole surface-mounted external rotor design with alternating A-type and B-type magnets addresses noise and torque fluctuations in permanent magnet hub motors, enhancing efficiency and reducing mechanical vibrations.
Patent Information
- Application Number
- CN202510520505.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2025-07-15
AI Technical Summary
The cogging torque of existing permanent magnet hub motors causes speed and torque fluctuations, causing motor noise and vibration problems.
Different-shaped A-type and B-type magnetic steels are used to alternately arrange on the inner annular surface of the rotor core to form uniform and uneven air gaps, adjacent magnetic poles are asymmetric, and torque fluctuations are reduced.
It effectively reduces motor noise and torque fluctuations, improves motor efficiency and reduces cogging torque fluctuations.
Smart Images
Figure CN120320529A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of motors, and particularly to a technology of a surface-mounted outer rotor with hybrid magnetic poles for a permanent magnet hub motor. Background Art
[0002] The air gap diameter of an outer rotor motor is larger than that of an inner rotor motor, and it has a high power factor, high efficiency, high output torque and moment of inertia, and is suitable for applications in low-speed, high-torque and direct drive occasions. However, the cogging torque of a permanent magnet hub motor will cause technical problems such as rotational speed and torque fluctuations, resulting in motor noise, vibration and deteriorated operation. Summary of the Invention
[0003] Aiming at the defects existing in the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a surface-mounted outer rotor with hybrid magnetic poles for a permanent magnet hub motor that can reduce motor noise and torque fluctuations.
[0004] In order to solve the above technical problem, a surface-mounted outer rotor with hybrid magnetic poles for a permanent magnet hub motor provided by the present invention includes a rotor core, and a plurality of permanent magnets are attached to the inner ring surface of the rotor core. It is characterized in that: There are two types of permanent magnets attached to the inner ring surface of the rotor core, namely type A permanent magnets and type B permanent magnets, and the type A permanent magnets and type B permanent magnets are alternately arranged around the rotating shaft of the outer rotor; The type A permanent magnet is arc-shaped in the radial cross-section of the rotor core, and the type B permanent magnet is bread-shaped with a thick middle and thin sides in the radial cross-section of the rotor core; let the distance between the inner side surface of the type A permanent magnet and the axis of the rotor core be R1, and the distance between the inner side surface of the type B permanent magnet and the axis of the rotor core be R2, then R1 = R2.
[0005] The surface-mounted outer rotor with hybrid magnetic poles for a permanent magnet hub motor provided by the present invention adopts alternately arranged surface-mounted permanent magnets with different shapes. One group of permanent magnets forms a uniform air gap with the stator, and the other group of permanent magnets forms a non-uniform air gap with the stator. The air gaps at both ends are large, and the air gap in the middle is small, forming asymmetric adjacent magnetic poles, which can effectively reduce torque fluctuations and improve the waveform of the air gap magnetic field of the motor. Brief Description of the Drawings
[0006] Figure 1 It is a schematic diagram of the radial cross-section of a surface-mounted outer rotor with hybrid magnetic poles for a permanent magnet hub motor according to an embodiment of the present invention. Detailed Description of the Embodiment
[0007] The following further describes the embodiments of the present invention in detail with reference to the accompanying drawings, but the embodiments do not limit the present invention. Any similar structure and its similar changes adopted in the present invention should be included in the protection scope of the present invention. The commas in the present invention all represent the relationship of "and".
[0008] As Figure 1As shown in the figure, a surface-mounted outer rotor with hybrid magnetic poles of a permanent magnet hub motor provided by an embodiment of the present invention includes a rotor core 2, and a plurality of permanent magnets are attached to the inner ring surface of the rotor core 2. It is characterized in that: There are two types of permanent magnets attached to the inner ring surface of the rotor core 2, namely type A permanent magnets 3 and type B permanent magnets 4. The type A permanent magnets and type B permanent magnets are alternately arranged around the rotating shaft of the outer rotor; The type A permanent magnet 3 is arc-shaped in the radial cross-section of the rotor core, and the type B permanent magnet 4 is bread-shaped with a thick middle and thin sides in the radial cross-section of the rotor core; let the distance between the inner side surface of the type A permanent magnet 3 and the axis of the rotor core be R1, and the distance between the inner side surface of the type B permanent magnet 4 and the axis of the rotor core be R2, then R1 = R2.
[0009] In the embodiment of the present invention, the type A permanent magnet 3 forms a uniform air gap with the stator, and the type B permanent magnet 4 forms a non-uniform air gap with the stator. The air gaps at both ends of the type B permanent magnet are large, and the air gap in the middle is small, forming asymmetry of adjacent magnetic poles, which can effectively reduce torque ripple and improve the air gap magnetic field waveform of the motor.
[0010] The motor with the permanent magnet outer rotor of this embodiment is compared with the existing outer rotor surface-mounted permanent magnet hub motor of the same specification. The parameters of the existing motor with an internal double-layer U-shaped permanent magnet rotor are: rated power is 3KW, rated current is 19.5A, efficiency is 91.5%, rated speed is 800r / min, maximum speed is 2000r / min, rated torque is 35.8Nm, and maximum torque is 78Nm; Compared with the existing outer rotor surface-mounted permanent magnet hub motor of the same specification, the motor with the permanent magnet outer rotor of the embodiment of the present invention has its efficiency increased from 91.5% to 93.8%, the cogging torque decreased from 1.75Nm to 0.82Nm, and the cogging torque ripple decreased from 4.9% to 2.3%; Thus, it can be seen that the embodiment of the present invention improves the air gap magnetic flux density waveform and reduces the motor noise and torque ripple.
Claims
1. A permanent magnet hub motor with a hybrid magnetic pole surface-mounted outer rotor, comprising a rotor core, and a plurality of permanent magnets are attached to the inner ring surface of the rotor core. It is characterized in that: There are two types of permanent magnets attached to the inner ring surface of the rotor core, namely type A permanent magnets and type B permanent magnets. The type A permanent magnets and the type B permanent magnets are alternately arranged around the rotating shaft of the outer rotor; The type A permanent magnets are arc-shaped in the radial cross-section of the rotor core, and the type B permanent magnets are bread-shaped with a thick middle and thin sides in the radial cross-section of the rotor core. Let the distance between the inner side surface of the type A permanent magnet and the axis of the rotor core be R1, and the distance between the inner side surface of the type B permanent magnet and the axis of the rotor core be R2, then R1 = R2.