Permanent magnet hub surface-mounted slot-added external rotor motor

Abstract

A permanent magnet hub surface-mounted slot-added external rotor motor relates to the technical field of motors, the motor comprises an external rotor and an internal stator, a plurality of magnetic steels are attached to the inner ring surface of the external rotor, and the magnetic steels are symmetrically arranged around the rotating shaft of the external rotor, and is characterized in that the middle part of the inner surface of each magnetic steel is provided with a semicircular groove; the end face of each stator tooth of the inner stator is provided with a semicircular groove. The motor 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 permanent magnet hub surface-mounted slotted external rotor motor. 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 surface-mounted slotted external rotor motor that can reduce motor noise and torque fluctuation.

[0004] To solve the above-mentioned technical problems, this utility model provides a permanent magnet hub-mounted slotted external rotor motor, including an external rotor and an inner stator. Multiple magnets are attached to the inner ring surface of the external rotor, and each magnet is symmetrically arranged around the rotation axis of the external rotor. Its characteristic is that:

[0005] A semi-circular groove is provided in the middle of the inner surface of each magnet, and a semi-circular groove is provided on the end face of each stator tooth of the inner stator.

[0006] The permanent magnet hub surface-mount slotted external rotor motor provided by this utility model can increase the fundamental frequency of the cogging torque ripple and reduce the amplitude of the fundamental and higher harmonic torques of the cogging without increasing the number of motor slots by opening semi-circular grooves on the magnetic pole surface and stator tooth surface. This reduces the torque ripple caused by the cogging and makes the radial force of the d-axis of the magnetic pole radial centerline and the q-axis of the inter-pole centerline tend to be balanced, which can effectively reduce torque ripple and improve the air gap magnetic field waveform of the motor. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the radial cross-section of the stator and rotor of the permanent magnet hub surface-mounted slotted external rotor motor 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 a relationship between and.

[0009] like Figure 1As shown in the figure, the permanent magnet hub surface-mounted slotted external rotor motor provided by this utility model includes an external rotor 2 and an inner stator 1. Multiple magnets 21 are attached to the inner ring surface of the external rotor 2, and each magnet 21 is symmetrically arranged around the rotation axis of the external rotor 2. Its characteristic is that:

[0010] A semi-circular groove 22 is provided in the middle of the inner surface of each magnet 21 (the side facing the inner stator 1 is the inner side), and a semi-circular groove 12 is provided on the end face of each stator tooth 11 of the inner stator 1.

[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 94.2%, a cogging torque that decreases from 1.75 Nm to 0.78 Nm, and a cogging torque fluctuation that decreases from 4.9% to 2.13%.

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

Claims

1. A permanent magnet hub-mounted slotted external rotor motor, comprising an external rotor and an inner stator, wherein multiple magnets are attached to the inner annular surface of the external rotor, and the magnets are symmetrically arranged around the rotation axis of the external rotor, characterized in that: A semi-circular groove is provided in the middle of the inner surface of each magnet, and a semi-circular groove is provided on the end face of each stator tooth of the inner stator.

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