Halbach Magnet Array Assembly With Asymmetric Non-Magnetic Layers
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Solution Overview
Problem
The manufacturing of Halbach magnet arrays is challenging due to repulsion between magnets, making it difficult to accurately control their positions, and existing methods result in a small ratio of magnetic-flux density at the front surface to that at the back surface.
Innovation Solution
A method involving the alternated arrangement of first, second, and third magnetic material pieces with non-magnetic layers of different thicknesses, where each piece is magnetized in specific directions, allowing for easy integration without large external forces and achieving a high ratio of magnetic-flux density at the front surface to the back surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a plurality of magnetized magnets are integrated together to form a Halbach magnetic circuit, then the surface magnetic-flux density distribution can be achieved, but repulsion between the magnets makes it difficult to accurately control the positions of the magnets and requires a large external force
Solution Approach 1:
The patent applies preliminary action by integrating the magnetic material pieces in an unmagnetized state before applying the magnetic field. This allows the pieces to be assembled without experiencing repulsive forces, making position control easier and reducing the external force required. After integration, a magnetic field is applied to magnetize the assembled pieces, achieving the desired Halbach magnetic circuit configuration.
2Ease of manufacture
If magnetic material pieces are integrated in an unmagnetized state followed by magnetizing, then integration is easier, but the ratio of magnetic-flux density at the front surface to that at the back surface becomes small
Solution Approach 1:
The patent applies local quality by creating asymmetric non-magnetic layers with different thicknesses (t1 and t2) between adjacent magnetic material pieces. This asymmetric structure locally modifies the magnetic flux distribution, allowing the front surface to have higher magnetic-flux density while the back surface has lower density, thus achieving a large flux density ratio even when integrating in an unmagnetized state.
3Reliability
If magnets are arranged with alternating polarities to achieve Halbach configuration, then the magnetic circuit function is achieved, but the repulsion forces increase making assembly difficult
Solution Approach 1:
The patent applies preliminary action by assembling all magnetic material pieces in their unmagnetized state, where no repulsive forces exist between them. This allows for easy assembly and accurate positioning. After the entire array is assembled, a magnetic field is applied to simultaneously magnetize all pieces, establishing the alternating polarity Halbach configuration without having dealt with repulsion forces during assembly.
4Device complexity
If non-magnetic layers of equal thickness are used between magnetic material pieces, then the structure is simple, but the magnetic-flux density ratio at front surface to back surface is reduced
Solution Approach 1:
The patent applies asymmetry by using non-magnetic layers with different thicknesses (t1 and t2) between adjacent magnetic material pieces. This asymmetric design creates an imbalance in the magnetic flux paths, allowing the front surface to concentrate more magnetic flux while the back surface has less, thereby achieving a large magnetic-flux density ratio. The asymmetric structure is intentionally designed to optimize magnetic performance rather than simplify the structure.
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
Facilitates the easy manufacture of Halbach magnet arrays with a large magnetic-flux density ratio at the front surface to the back surface, overcoming integration challenges and repulsion issues, while allowing for precise positioning without requiring large external forces.
Implementation Method 1
each of the at least one first magnetic material piece adheres to the adjacent third magnetic material piece via a non-magnetic layer with a thickness t1, wherein each of the at least one second magnetic material piece adheres to the adjacent third magnetic material piece via a non-magnetic layer with a thickness t2, wherein the thickness t1 and the thickness t2 satisfy a formula t1<t2
Implementation Method 2
a) magnetizing at least one first magnetic material piece and at least one second magnetic material piece in a direction parallel to a first direction, wherein the direction of magnetizing the at least one first magnetic material piece is different from the direction of magnetizing the at least one second magnetic material piece by 180°
Data Source
AI summary
The method for manufacturing the Halbach magnet array comprises a) magnetizing at least one first magnetic material piece and at least one second magnetic material piece in a direction parallel to a first direction, and b) magnetizing a third magnetic material piece in a direction parallel to a second direction perpendicular to the first direction, in this order. The first magnetic material piece and the second magnetic material piece are alternately arranged in the second direction with the third magnetic material piece interposed therebetween. The first magnetic material piece adheres to the adjacent third magnetic material piece via a non-magnetic layer with a thickness t1, the second magnetic material piece adhere to the adjacent third magnetic material piece via a non-magnetic layer with a thickness t2, and t1 and t2 satisfy a formula t1<t2.