One-Piece Stator Teeth Rectangular Section for High-Speed Motor Noise
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Solution Overview
Problem
High-speed rotating electrical machines above 20,000 RPM face challenges in minimizing vibrations and sound emissions due to resonance issues, with existing solutions requiring complex constructions, additional parts, and precise control of tolerances, impacting performance and cost.
Innovation Solution
A one-piece stator design with a peripheral annular crown supporting 3 or 6 straight teeth, where the teeth have a rectangular section with specific dimensions to push resonant frequencies beyond the audible spectrum, and a thickness and outer diameter ratio optimized to minimize noise emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a one-piece stator is used, then the construction is simple, but resonance eigenmodes occur at harmful frequencies
Solution Approach 1:
The patent changes the geometric parameters of the stator teeth, specifically setting the width-to-length ratio between 1/3 and 1/10 and the thickness-to-outer diameter ratio between 1/10 and 1/20. These parameter changes push the resonant frequency above 16 kHz, moving it out of the harmful audible range while maintaining the simple one-piece construction.
2Object-generated harmful factors
If the stator is separated into several blocks, then resonance frequency is overcome, but construction complexity and tolerance control increase
Solution Approach 1:
Instead of separating the stator into blocks, the patent modifies the dimensional parameters of a one-piece stator. By optimizing the tooth width-to-length ratio and crown thickness-to-outer diameter ratio, the resonant frequency is shifted above 16 kHz, achieving noise reduction without increasing construction complexity.
3Object-generated harmful factors
If additional damping parts are added to the stator, then noise emissions are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent achieves noise reduction by changing the geometric parameters of the stator itself (tooth dimensions and crown thickness) rather than adding external damping parts. This approach maintains ease of manufacture while effectively pushing resonant frequency above 16 kHz.
4Object-generated harmful factors
If magnets are added to the rotor to counter salience effects, then motor noise is reduced, but magnet mass and cost increase
Solution Approach 1:
The patent addresses motor noise by changing the stator's geometric parameters (tooth width-to-length ratio and crown thickness-to-outer diameter ratio) rather than adding magnets to the rotor. This approach reduces noise by pushing resonant frequency above 16 kHz without increasing magnet mass or cost.
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 design effectively reduces noise emissions by pushing resonant frequencies above 16 kHz, maintaining dynamic performance similar to traditional stators while minimizing sound levels, with a notable 20 dB gain in acoustic performance.
Implementation Method 1
the wound teeth having a rectangular section of width l and length L, with l/L expressed in SI units, in order to push the resonant frequency of each tooth beyond the audible spectrum, typically ≥16 kHz
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a high-speed electric machine, having a speed higher than 20,000 rpm, comprising a rotor (1) having 1 or 2 pairs of magnetized poles, and an enhanced stator (2) which has an outer diameter that is larger than 18 millimeters and which has 3 or 6 straight teeth (3) extending radially and borne by a one-piece peripheral annular collar (5), at least a portion of the teeth (3) bearing coils (4), said teeth (3) being rigidly connected to one another and together forming a one-piece planar assembly; according to the invention, the coiled teeth (3) have a rectangular cross-section of width I and of length L, with formula (I).