Variable Reluctance Actuator with Segmented Armature Slots
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Solution Overview
Problem
Existing electromagnetic actuators face challenges in achieving high force density and low eddy current losses, with lamination leading to mechanical weakness and limited lifespan, and solid armatures experiencing excessive energy losses, making them unsuitable for applications requiring high power and precision in compact, lightweight designs.
Innovation Solution
An electromagnetic actuator with a variable reluctance design featuring a fixed armature with concentric cylinders and double series of slots that increase electrical resistance without compromising mechanical integrity, allowing for precise machining and reduced eddy current propagation, combined with a discoidal movable armature and specific slot distributions to optimize magnetic flux and mechanical retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If lamination is used to increase electrical resistance and reduce eddy current losses, then energy efficiency is improved, but mechanical strength is weakened
Solution Approach 1:
The fixed armature is segmented into multiple slots radially distributed around the circumference, dividing the continuous ferromagnetic material into discrete sections. This segmentation increases electrical resistance to eddy currents while preserving mechanical strength through the slot structure and connection ring design
Solution Approach 2:
The fixed armature combines ferromagnetic material with a connection ring structure, creating a composite design where the connection ring provides mechanical reinforcement while the slotted ferromagnetic sections provide electromagnetic functionality with reduced eddy current losses
2Strength
If solid armatures are used to maintain mechanical strength, then structural integrity is improved, but eddy current losses increase
Solution Approach 1:
The solid armature structure is modified by introducing radial slots that segment the ferromagnetic material, breaking up eddy current paths while maintaining the overall solid structure and mechanical strength through the connection ring
3Loss of energy
If lamination is applied to reduce eddy current losses, then energy efficiency is improved, but manufacturing precision is reduced
Solution Approach 1:
Instead of laminating thin sheets, the invention segments the solid armature by machining radial slots, which can be precisely manufactured while maintaining full material integrity and avoiding lamination alignment issues
Solution Approach 2:
The invention changes the approach from modifying material structure (lamination) to modifying geometry (slots), allowing precise machining of the slot dimensions and positions while maintaining the solid armature's mechanical properties
4Loss of energy
If lamination is used to reduce eddy current losses, then energy efficiency is improved, but service life is reduced
Solution Approach 1:
The slot segmentation approach avoids the use of varnish and lamination layers that degrade over time, using instead a robust geometric feature that can be precisely machined and maintains its properties throughout the actuator's service life
Solution Approach 2:
The invention eliminates the use of varnish coatings and lamination materials that have limited lifespan and are susceptible to environmental degradation, opting for a purely geometric slot structure that is more durable
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 actuator achieves significant force generation per unit volume or mass with reduced hysteresis losses, enhanced mechanical strength, and extended lifespan, suitable for high-frequency applications, such as satellite propulsion systems, while maintaining energy efficiency and compact dimensions.
Implementation Method 1
at least one magnetization coil arranged between said inner cylinders and exterior... capable of developing significant forces per unit volume or mass of the actuator
Implementation Method 2
Since ferromagnetic materials are electrically conductive, the eddy currents induced by these induction variations lead to power losses
Implementation Method 3
electromagnetic actuator with variable reluctance... with which it defines a magnetic circuit with an air gap whose dimension varies during the alternating translations
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to an electromagnetic actuator with variable reluctance comprising a fixed ferromagnetic armature (3) comprising at least two concentric cylinders of revolution linked by a ring nut, at least one magnetizing winding (2) arranged between said cylinders, a ferromagnetic moving armature (4) guided in reciprocating translation movements relative to said fixed armature (3), with which it defines a magnetic circuit with an air gap (20), the dimension of which varies during reciprocating translation movements of the moving armature (4), characterized in that said fixed armature (3) comprises at least two series of slots, a first series of slots provided radially in said outer cylinder and extending over the entire height of said outer cylinder, and a second series of slots provided radially in said outer and inner cylinders and extending only over a major part of the height of said cylinders.