Motor and washing machine having the same
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Solution Overview
Problem
Washing machines experience noise and vibration issues due to large cogging torque and torque ripple caused by uneven magnetic pole distribution in the motor's permanent magnets, leading to manufacturing defects and reduced motor quality.
Innovation Solution
A rotor design with permanent magnets arranged at regular intervals, each exhibiting one magnetic polarity, and spaced apart at specific angles to minimize dead zones and uniform magnetic flux density, reducing cogging torque and torque ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If permanent magnets are arranged with multiple magnetic poles on a void surface, then magnetic pole distribution can be increased, but dead zones of different sizes are formed causing large cogging torque and torque ripple
Solution Approach 1:
The rotor is divided into multiple independent permanent magnets instead of using a single magnet with multiple poles. Each permanent magnet has a uniform dead zone, and by segmenting the rotor into multiple such magnets arranged at specific angles, the overall magnetic pole distribution becomes uniform, eliminating the problem of uneven dead zones while maintaining the required number of magnetic poles
Solution Approach 2:
The invention changes the geometric parameters of the permanent magnets, specifically setting the pole arc to pole pitch ratio within a specific range (0.5-0.7) and arranging magnets at specific angle intervals. This parameter optimization ensures uniform magnetic flux density distribution and minimizes cogging torque and torque ripple
2Reliability
If permanent magnets are arranged to increase magnetic pole distribution, then cogging torque and torque ripple are reduced, but the complexity of determining optimal angles and spacing increases
Solution Approach 1:
The invention establishes specific parameter ranges for pole arc to pole pitch ratio (0.5-0.7) and angle intervals between permanent magnets. By defining these parameters within optimized ranges rather than requiring precise individual calculations, the complexity of design is reduced while still achieving the goal of minimizing cogging torque and torque ripple for reliable motor operation
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
This design reduces noise and vibration in washing machines, improves motor starting and acceleration characteristics, and enhances manufacturing efficiency by allowing easier assembly and defect detection, leading to improved product quality and user satisfaction.
Implementation Method 1
a motor comprises: a stator having slots around which coils are wound; and a rotor comprising a housing having a circular shape and accommodating the stator and a plurality of permanent magnets disposed on an inner surface of the housing to be spaced apart from each other while facing the slots
Implementation Method 2
the plurality of permanent magnets provided corresponding in number to a number of magnetic poles and having different magnetic polarities
Data Source
AI summary
A motor of the invention includes a stator having a slot wound with a coil and a circular shaped housing accommodating the stator, and a rotor disposed on an inner surface of the housing and spaced apart from the slot and having a plurality of permanent magnets having the same number as magnetic poles and having different magnetic polarities. Each of the plurality of permanent magnets has a length corresponding to a first angle according to the number of magnetic poles. The plurality of permanent magnets are spaced apart from each other at a third angle according to the first angle and a second angle corresponding to the number of magnetic poles. The first, second, third angles of the motor refer to a center point of the housing as an angle reference point. The motor of an embodiment may be a motor provided in a washing machine.