Ovoid Unitary Magnet Structure for High-Speed Actuator Demagnetization
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Solution Overview
Problem
High-speed electromagnetic actuators face challenges in maintaining mechanical strength and preventing demagnetization of permanent magnets due to high temperatures and Foucault currents, which are costly to address with existing solutions.
Innovation Solution
A magnet structure composed of elongated ellipsoidal or poly-faceted unitary magnets that are directly adjacent and adhesively connected, forming a mesh structure without additional retention elements, which approximates an ovoid shape to enhance resistance to demagnetization and reduce Foucault currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If unitary magnets are divided into smaller pieces to reduce Foucault currents, then energy losses are reduced, but manufacturing cost increases and output decreases
Solution Approach 1:
The magnet structure is segmented into multiple unitary magnets arranged in a specific configuration, which interrupts Foucault current paths while maintaining manufacturing efficiency. The segmentation is achieved by positioning unitary magnets with their magnetic axes parallel and spaced to break eddy current loops without requiring complex manufacturing processes.
Solution Approach 2:
The solution moves from two-dimensional planar magnet arrangements to a three-dimensional configuration where unitary magnets are stacked with alternating polarities. This dimensional transition creates multiple magnetic zones that effectively interrupt Foucault currents throughout the volume of the rotor, providing superior loss reduction compared to planar segmentation.
2Loss of energy
If unitary magnets are divided into smaller pieces to reduce Foucault currents, then energy losses are reduced, but output decreases
Solution Approach 1:
The rotor is segmented into multiple unitary magnets arranged in alternating polarity configurations, which interrupt Foucault current paths. This segmentation reduces eddy current losses while the strategic arrangement maintains magnetic field strength and torque production capability.
Solution Approach 2:
By transitioning to a three-dimensional arrangement of unitary magnets with alternating polarities in stacked configurations, the invention creates multiple magnetic zones that simultaneously reduce Foucault currents and maintain strong magnetic fields for high power output.
3Power
If magnets are exposed to high temperatures during high-speed operation, then the actuator achieves high power output, but demagnetization occurs
Solution Approach 1:
The magnet structure is divided into multiple unitary magnets with alternating polarities, creating multiple smaller magnetic zones. This segmentation reduces the demagnetizing field strength in each individual magnet while maintaining overall magnetic field strength, thereby improving resistance to thermal demagnetization during high-speed operation.
Solution Approach 2:
The arrangement of alternating polarity unitary magnets creates intermediate magnetic zones between adjacent magnets of opposite polarity. These intermediate zones act as magnetic shields that reduce the demagnetizing field exposure of each individual magnet, protecting against thermal demagnetization while allowing high power output.
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 solution provides a compact, reliable magnet structure that withstands high speeds and maintains a strong magnetic field while minimizing demagnetization and Foucault current losses, allowing for a large number of unitary magnets to be integrated without increasing manufacturing costs.
Implementation Method 1
the rotor which is fastened to the output shaft of the motor is subjected to a torque resulting from the magnetic field
Implementation Method 2
permanent magnets are exposed to a high temperature on account of the heat generated by the windings
Implementation Method 3
When the rotor rotates, Foucault currents circulate in the magnets
Implementation Method 4
adhesively connected, forming a mesh structure without additional retention elements
Data Source
AI summary
The invention relates to a unitary magnet (1) that has an elongate shape and an at least partially ovoid contour as the unitary magnet (1) comprises a first portion (1a) forming a body of the unitary magnet (1) that has a larger cross-section and extends over a greater portion of the length of the unitary magnet (1) than at least one second longitudinal end portion (1b) that points towards an associated longitudinal end of the magnet and has a decreasing cross-section towards the longitudinal end.