Brushless DC Motor Stator Tooth Configuration for Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Brushless DC electric motors used in motor vehicle equipment, such as wiper devices, often produce noise due to their operational characteristics, which existing designs have not adequately addressed to achieve a low sound level while maintaining performance.
Innovation Solution
A brushless DC electric motor design featuring a stator with two types of teeth covering different electrical angles and using square wave commands to generate electromotive forces that resemble sinusoidal forms, resulting in a 'softer' operation and reduced noise, along with increased torque at slower speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional brushless DC motor design is used, then the motor structure is simple and manufacturing is easy, but the noise level is high
Solution Approach 1:
The stator is segmented into two distinct types of teeth (first type and second type) with different electrical angles, allowing each tooth type to contribute differently to the electromagnetic excitation and enabling a more refined control over the electromotive force waveform to reduce noise
Solution Approach 2:
Different regions of the stator (different tooth types) are given different electrical angle characteristics to optimize local electromagnetic performance, with the first type of tooth and second type of tooth each covering specific electrical angles that collectively produce a softer electromotive force waveform
2Object-affected harmful factors
If square wave commands are applied to coils, then the control is simple, but the electromotive force waveform is not sinusoidal causing higher noise
Solution Approach 1:
The electrical angles covered by different tooth types are specifically designed with a ratio between 0.6 and 0.9, and the winding turns are adjusted accordingly, transforming the simple square wave control into an effective sinusoidal-like electromotive force output that reduces noise while maintaining control simplicity
3Force
If conventional single tooth type is used, then the motor structure is simple, but the torque at slow speed is insufficient
Solution Approach 1:
The winding system is segmented into different configurations (series connections, parallel connections forming subsets) associated with different tooth types, allowing optimized torque generation at slow speeds through selective activation and combination of winding paths
Solution Approach 2:
The number of turns in windings associated with different tooth types is specifically configured (either equal, or with one type having more/less turns), and the connection topology is changed between series and parallel arrangements to optimize the torque output at slow speeds
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 a lower noise level and enhanced performance by producing a torque that is greater at slower speeds, with the unique tooth configuration and winding arrangements effectively mimicking sinusoidal operation.
Implementation Method 1
a stator having a plurality of teeth around which windings forming coils for electromagnetic excitation of the rotor are wound
Implementation Method 2
the torque generated at a slow speed of rotation is greater
Data Source
AI summary
The present invention relates to a brushless dc electric motor (1) comprising:a rotor (3) comprising at least two pairs of poles,a stator (5) having a plurality of teeth (D1, D2) around which windings (B1, B2, B3, B′1, B′2, B′3) forming coils for electromagnetic excitation of the rotor (3) are wound,wherein the stator (5) comprises a first type of tooth (D1) covering a first electrical angle and a second type (D2) of tooth covering a second electrical angle different from the first electrical angle and wherein a phase of the motor is formed by windings (B1, B′1 or B2, B′2 or B3, B′3) wound onto teeth of the first type (D1) and second type (D2).