Permanent magnet hub motor combined magnetic pole surface-mounted outer rotor

Abstract

A combined magnetic pole surface-mounted outer rotor of a permanent magnet hub motor relates to the technical field of motors, a rotor core of the rotor is provided with a plurality of magnetic steel groups, each magnetic steel group is symmetrically arranged around a rotating shaft of the rotor core, and each magnetic steel group comprises first magnetic steel, second magnetic steel and third magnetic steel which are sequentially arranged at intervals along the circumferential direction of the rotor core. The pole arc widths of the first magnetic steel, the second magnetic steel and the third magnetic steel are different; if the pole arc width of the first magnetic steel is a, the pole arc width of the second magnetic steel is b, the pole arc width of the third magnetic steel is c, and the magnetic pole distance among the first magnetic steel, the second magnetic steel and the third magnetic steel is x, a gt exists; bgt; c, a = b + x, and b = c + x. The rotor provided by the utility model can reduce motor noise and torque ripple.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a technology for a permanent magnet hub motor with a magnetic pole surface-mounted external rotor. Background Technology

[0002] The air gap diameter of the external rotor motor is larger than that of the internal rotor, which has a high power factor, high efficiency, high output torque and rotational inertia. It is suitable for low-speed, high-torque and direct drive applications. However, the cogging torque of the permanent magnet hub motor will cause speed and torque fluctuations, resulting in technical problems such as motor noise, vibration and deterioration of operation. Utility Model Content

[0003] In view of the defects existing in the prior art, the technical problem to be solved by this utility model is to provide a permanent magnet hub motor with a magnetic pole surface-mounted external rotor that can reduce motor noise and torque fluctuation.

[0004] To solve the above-mentioned technical problems, the present invention provides a permanent magnet hub motor with a combined magnetic pole surface-mounted external rotor, including a rotor core, characterized in that: the rotor core is provided with multiple magnetic steel groups, each magnetic steel group is symmetrically arranged around the rotation axis of the rotor core, each magnetic steel group includes a first magnet, a second magnet and a third magnet arranged sequentially and at intervals along the circumference of the rotor core, and the pole arc widths of the first magnet, the second magnet and the third magnet are different;

[0005] Let the pole arc width of the first magnet be a, the pole arc width of the second magnet be b, the pole arc width of the third magnet be c, and the pole spacing between the first, second, and third magnets be x. Then we have a>b>c, a=b+x, and b=c+x.

[0006] The permanent magnet hub motor with combined magnetic pole surface-mounted outer rotor provided by this utility model uses three magnets with different pole arc widths as a group, which are alternately attached to the outer rotor to form asymmetric magnetic poles. The stator does not need skewed slots, the rotor does not need skewed poles, and there is no need to set uneven air gap between the stator and the rotor, which can effectively reduce torque fluctuation and improve the air gap magnetic field waveform of the motor. Attached Figure Description

[0007] Figure 1 This is a radial cross-sectional schematic diagram of the permanent magnet hub motor assembly with surface-mounted magnetic poles and an external rotor according to an embodiment of this utility model. Detailed Implementation

[0008] The embodiments of this utility model are described in further detail below with reference to the accompanying drawings. However, these embodiments are not intended to limit this utility model. Any similar structures or variations thereof that adopt this utility model should be included in the protection scope of this utility model. The commas in this utility model all indicate the relationship between and.

[0009] like Figure 1 As shown in the embodiment of this utility model, a permanent magnet hub motor with a combined magnetic pole surface-mounted external rotor includes a rotor core 2. The rotor core 2 is characterized by having multiple magnetic steel groups, each magnetic steel group being symmetrically arranged around the rotation axis of the rotor core 2. Each magnetic steel group includes a first magnet 21, a second magnet 22, and a third magnet 23 arranged sequentially and at intervals along the circumference of the rotor core 2, and the pole arc widths of the first magnet 21, the second magnet 22, and the third magnet 23 are different.

[0010] Let the pole arc width of the first magnet 21 be a, the pole arc width of the second magnet 22 be b, the pole arc width of the third magnet 23 be c, and the pole spacing between the first magnet 21, the second magnet 22 and the third magnet 23 be x. Then we have a>b>c, a=b+x, b=c+x.

[0011] The permanent magnet external rotor motor of this embodiment was compared with the existing external rotor surface-mounted permanent magnet hub motor of the same specification. The parameters of the existing built-in double-layer U-shaped permanent magnet rotor motor are: rated power of 3KW, rated current of 19.5A, efficiency of 91.5%, rated speed of 800r / min, maximum speed of 2000r / min, rated torque of 35.8Nm, and maximum torque of 78Nm.

[0012] Compared with existing surface-mounted permanent magnet hub motors of the same specifications, the motor with the permanent magnet external rotor of this utility model has an efficiency that increases from 91.5% to 93.8%, a cogging torque that decreases from 1.75 Nm to 0.86 Nm, and a cogging torque fluctuation that decreases from 4.9% to 2.7%.

[0013] Therefore, the present invention improves the air gap flux density waveform and reduces motor noise and torque fluctuation.

Claims

1. A permanent magnet wheel hub motor combination magnetic pole surface-mounted outer rotor, comprising a rotor core, characterized in that: The rotor core is provided with multiple magnet groups, each magnet group is symmetrically arranged around the rotation axis of the rotor core, each magnet group includes a first magnet, a second magnet and a third magnet arranged sequentially and at intervals along the circumference of the rotor core, and the pole arc widths of the first magnet, the second magnet and the third magnet are different. Let the pole arc width of the first magnet be a, the pole arc width of the second magnet be b, the pole arc width of the third magnet be c, and the pole spacing between the first, second, and third magnets be x. Then we have a>b>c, a=b+x, and b=c+x.

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