Motor Stator Pole Offset for Noise Reduction
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Solution Overview
Problem
Motors used in display devices face challenges in reducing noise generated when the rotor is accelerated or decelerated, as existing designs fail to provide sufficient excitation torque and result in excessive vibration.
Innovation Solution
A motor design featuring a rotor with S-poles and N-poles alternately arranged on its peripheral face and a stator with six salient poles, where the coils are wound around specific salient poles positioned to face the center of S-poles or N-poles, reducing detent torque variation and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If three pairs or five pairs of S-poles and N-poles are disposed on the magnet with eight salient poles on the stator, then the excitation torque is sufficient for rotor rotation, but the detent torque variation is large causing excessive vibration and noise
Solution Approach 1:
The patent changes the parameters of the motor structure by using four pairs of S-poles and N-poles on the magnet with six salient poles on the stator, and specifically positioning the first and second salient poles at angular positions shifted by 112.5°. This parameter change optimizes the magnetic field distribution to reduce detent torque variation while maintaining sufficient excitation torque, thereby reducing vibration and noise.
2Device complexity
If the first and second salient poles are positioned at equal angular intervals, then the structure is simple, but the excitation torque is insufficient for rotor rotation
Solution Approach 1:
The patent changes the angular position parameter of the first and second salient poles from equal angular intervals to a specific shift of 112.5°. This parameter optimization ensures that the salient poles face the center of S-poles or N-poles at appropriate positions, generating sufficient excitation torque for rotor rotation while maintaining reasonable structural simplicity.
3Object-generated harmful factors
If four pairs of S-poles and N-poles are disposed on the magnet with six salient poles on the stator, then the detent torque variation is reduced minimizing vibration and noise, but the excitation torque may be insufficient
Solution Approach 1:
The patent optimizes the angular position parameter of the first and second salient poles by shifting them by 112.5° relative to each other. This specific parameter setting ensures that when one salient pole faces between S-pole and N-poles, the other salient pole faces the center of an S-pole or N-pole, thereby generating sufficient excitation torque while maintaining reduced detent torque variation.
Solution Approach 2:
The patent applies local quality by making the first and second salient poles have different angular positions compared to other salient poles. This localized differentiation in position allows the motor to achieve both sufficient excitation torque and reduced detent torque variation, as these specific poles play critical roles in torque generation while the overall structure maintains low vibration and noise.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The motor achieves sufficient excitation torque for rotor rotation while minimizing detent torque variation, leading to reduced vibration and noise when the rotor is accelerated or decelerated, and allows for efficient punching of magnetic plates for the stator core.
Implementation Method 1
a rotor (5) having a magnet (6) whose peripheral face is alternately provided with an S-pole and an N-pole
Implementation Method 2
a stator (7) having a stator core (8) in which a plurality of salient poles (80) facing the peripheral face through a gap space is disposed
Implementation Method 3
a first coil (76) which is wound around a first salient pole (81) of the plurality of the salient poles (80), and a second coil (77) which is wound around a second salient pole (82)
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(c)
Figure 3(a)~3(b)
AI summary
In a motor (1), a magnet (6) is configured so that four pairs of S-poles and N-poles are formed at equal angular intervals, and a stator core (8) has six salient poles (80) formed thereon. Of the plurality of salient poles (80), a first salient pole (81) having a first coil (76) wound therearound and a second salient pole (82) having a second coil (77) wound therearound are offset from each other by an angle of 112.5°. When the first salient pole (81) or the second salient pole (82) faces a position between an S-pole and an N-pole, the other salient pole faces the center of an S-pole or the center of an N-pole. The radial-direction lengths of the first salient pole (81) and the second salient pole (82) among the plurality of salient poles (80) are longer than the other salient poles (80), and the radial-direction length of the portion of the first coil (76) wound around the first salient pole (81) and the radial-direction length of the portion of the second coil (77) wound around the second salient pole (82) are longer than the radial-direction lengths of the other salient poles (80). Thus, the volume of the sound generated during acceleration or deceleration of the rotor is reduced.