Washing Machine Rotor Halbach Array Torque
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Solution Overview
Problem
Permanent magnet rotors in washing machines, particularly those using ferrite magnets, have limited torque capacity, which can be improved by enhancing magnetic flux, and existing methods do not effectively utilize magnetic arrays to maximize torque in direct drive washing machines.
Innovation Solution
A method of manufacturing a rotor for an electric motor in washing machines involves securing a plurality of permanent magnets to form a Halbach array, bending a metallic strip to create a yoke, and molding a polymeric material over the magnets and yoke to form a cylindrical shell, thereby increasing magnetic flux and torque capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ferrite magnets are used in the rotor, then the rotor can be manufactured with limited cost, but the torque capacity is limited
Solution Approach 1:
The patent combines ferrite magnets with a specific magnetic circuit design including a yoke and flux concentrating structures to create a composite magnetic system that enhances torque output while maintaining cost-effectiveness of ferrite materials
Solution Approach 2:
The patent optimizes geometric parameters of the magnetic circuit including yoke thickness, flux concentrating structure dimensions, and magnet arrangement to maximize magnetic flux density and torque capacity within the constraints of ferrite magnet material properties
2Ease of manufacture
If a regular disposition of magnets is used, then the manufacturing process is simple, but the magnetic flux is reduced
Solution Approach 1:
The patent employs asymmetric magnet arrangements and flux concentrating structures with non-uniform geometries to direct and enhance magnetic flux density in critical regions, improving magnetic flux compared to symmetric regular dispositions
Solution Approach 2:
The patent implements flux concentrating structures such as protrusions or grooves in specific locations of the magnetic circuit to locally enhance magnetic flux density where needed, rather than uniformly distributing magnetic properties throughout the entire structure
3Power
If magnetic field is augmented on one side of the array, then the magnetic flux is boosted, but the field on the opposite side is reduced or canceled
Solution Approach 1:
The patent strategically positions flux concentrating structures and designs the magnetic circuit to redirect the reduced or canceled field from one side of the magnet array through the yoke and core structures to reinforce the augmented field on the opposite side, converting potential harmful field cancellation into beneficial flux reinforcement
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 method enhances magnetic flux and torque capacity of the rotor, improving the efficiency of the electric motor in washing machines by forming a Halbach array of magnets and integrating a metallic yoke within a polymeric shell, which boosts magnetic field strength and reduces field cancellation.
Implementation Method 1
The rotor includes one or more magnets that interact with the stator coils. During operation, the stator coils may be sequentially energized with electricity to cause the rotor to rotate.
Implementation Method 2
the stator coils may be sequentially energized with electricity to cause the rotor to rotate
Implementation Method 3
The physical disposition of different orientation of magnets in a Halbach array may boost the magnetic flux generated, compared with a regular disposition of magnets, by augmenting the magnetic field on one side of the array while reducing or canceling the field on the opposite side of the array.
Data Source
AI summary
A method of manufacturing a rotor of an electric motor is disclosed. The method includes securing a plurality of permanent magnets to a sheet to form a magnet chain, bending the sheet to engage an inner surface of each permanent magnet with a curved outer surface of an insert mold, wrapping a metallic strip around an outer surface of the sheet to form a yoke of the rotor, and molding a polymeric material over the magnet chain and the yoke to form a cylindrical shell.