Flux-Balanced Electromagnetic Actuator for High Force Density
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Solution Overview
Problem
Reciprocating electromagnetic actuators with permanent magnets often face limitations in force density, cost, and reliability due to temperature constraints and demagnetization issues, and uniform armature designs fail to provide adequate magnetic flux control for certain applications.
Innovation Solution
The design features a flux-balanced armature with a ferromagnetic material and stationary cores configured to maximize magnetic flux, using ring coils and return springs to achieve high force density and precise control of magnetic flux through independent power source control of the coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If permanent magnets are used in reciprocating electromagnetic actuators, then actuation force is improved, but reliability deteriorates due to temperature constraints and demagnetization issues
Solution Approach 1:
The patent removes permanent magnets from the armature and replaces them with ferromagnetic material. The actuation force is generated entirely by electromagnetic interaction between the stationary cores and the armature, eliminating the permanent magnets that cause reliability issues while maintaining force generation capability
Solution Approach 2:
The patent uses ferromagnetic material in the armature that responds to electromagnetic fields from stationary cores, creating a functional equivalent to permanent magnet actuators without the reliability problems. The ferromagnetic armature is magnetized temporarily by the stationary cores during operation
2Force
If permanent magnets are used in reciprocating electromagnetic actuators, then actuation force is improved, but cost increases
Solution Approach 1:
The patent replaces expensive permanent magnets with cheaper ferromagnetic material that can be easily manufactured. The ferromagnetic armature is a simpler, more cost-effective component that achieves the same functional result without the high material costs of permanent magnets
3Ease of manufacture
If uniform or flat surface armatures are used, then manufacturing is simplified, but magnetic flux control is inadequate
Solution Approach 1:
The patent introduces non-uniform features on the armature surface, specifically annular grooves or protrusions that create localized variations in magnetic flux distribution. These local modifications enhance magnetic flux control and actuation force without significantly complicating the overall manufacturing process
Solution Approach 2:
The flux-balanced armature design creates uniform magnetic flux distribution across the air gap by carefully controlling the magnetic path. The armature geometry is optimized to ensure equipotential magnetic flux lines, improving flux control and actuation efficiency
4Force
If stationary cores with annular portions are used, then magnetic flux is maximized, but device complexity increases
Solution Approach 1:
The stationary cores are divided into multiple segments with annular portions at different axial positions. This segmentation allows independent control of magnetic flux in different regions, maximizing overall magnetic flux while maintaining modular construction that simplifies manufacturing and assembly
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 configuration enhances actuation forces, improves reliability, and allows for precise control of magnetic flux, addressing the limitations of existing actuators by maximizing force density and reducing mechanical friction and wear.
Implementation Method 1
stationary cores configured to maximize magnetic flux, using ring coils and return springs to achieve high force density and precise control of magnetic flux through independent power source control of the coils
Implementation Method 2
ferromagnetic armature configured to reciprocate between the stationary cores
Data Source
AI summary
An apparatus for electromagnetic actuation includes a cylindrical housing (6). The apparatus further includes at least two stationary cores (1A, 1B) fixed to the cylindrical housing (6). Each stationary core (1A, 1B) includes at least one first annular portion having a first annular thickness between a first inner diameter and a first outer diameter. The apparatus further includes a ring coil fixed to and in operable communication with each of the at least two stationary cores. The apparatus further includes a ferromagnetic armature (3) concentrically aligned with the at least two stationary cores and configured to move relative to the at least two stationary cores (1A, 1B). The ferromagnetic armature (3) has at least one second annular portion having a second annular thickness between a second inner diameter and a second outer diameter. The second annular thickness is about the same as the first annular thickness.