Direct-Drive Laundry Motor Pole Layout for Lower Noise
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Solution Overview
Problem
Conventional stators in laundry machine motors, particularly those with a 4:3 rotor pole to stator pole ratio, face challenges in noise reduction and resonance susceptibility, leading to increased costs and operational noise.
Innovation Solution
A stator design featuring a magnetically permeable core with an annular ring and radially extending poles, combined with a three-phase winding configuration and a diaphragm portion for mounting, along with a rotor having a permanent magnet ring with anisotropically aligned magnetic domains to produce a Halbach-style magnetic flux field, which reduces noise and resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional stators with more than 30 stator poles are used in motors with 4:3 rotor pole to stator pole ratio, then the motor can provide sufficient torque and power for laundry machines, but the noise level increases and resonance susceptibility increases
Solution Approach 1:
The patent changes the stator pole count parameter from the conventional more than 30 poles to exactly 24 or 27 poles. This parameter change optimizes the magnetic field distribution and reduces resonance frequencies that cause noise, while maintaining the 4:3 rotor-to-stator pole ratio for sufficient torque production.
Solution Approach 2:
The patent applies different winding configurations to different pole groups. Specifically, it uses distributed windings for some poles and concentrated windings for others, creating local variations in magnetic field characteristics that reduce overall noise and vibration while maintaining power output.
2Power
If conventional stators with more than 30 stator poles are used, then the motor can deliver required performance, but resonance susceptibility increases leading to operational issues
Solution Approach 1:
The patent modifies the stator pole count from conventional values (more than 30) to 24 or 27 poles. This parameter change shifts the resonant frequencies away from operational ranges, reducing resonance susceptibility while maintaining the 4:3 pole ratio for adequate torque and power delivery.
3Ease of manufacture
If conventional stator designs are used, then manufacturing follows established processes, but noise reduction and resonance control require increased costs
Solution Approach 1:
The patent adopts 24 or 27 stator poles instead of conventional more than 30 poles. This parameter change enables noise reduction through optimized magnetic field distribution without requiring complex additional components or expensive manufacturing processes, maintaining ease of production while improving acoustic performance.
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 described stator and rotor configuration results in lower noise levels and reduced resonance, making the motor more cost-effective and quieter, with improved operating characteristics compared to prior art stators.
Implementation Method 1
three phase windings, each winding comprising a plurality of coils arranged on one third of the pole cores
Implementation Method 2
a rotor having a permanent magnet ring with anisotropically aligned magnetic domains to produce a Halbach-style magnetic flux field
Implementation Method 3
permanent magnet ring with anisotropically aligned magnetic domains
Data Source
AI summary
A motor suited for use in a direct drive laundry machine. The described motor has a stator core including an annular ring with an inner diameter between 120 mm and 250 mm, a radial width between 5 mm and 15 mm, and 24 or 27 stator poles projecting outward from the annular ring a distance of between 15 mm and 40 mm. Each stator pole is associated with one of three phase windings. A rotor for the motor has inwardly facing permanent magnet poles whereby the ratio of rotor poles to stator poles is 4:3.