Electromagnetic Actuator Constant Force Design
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Solution Overview
Problem
Existing short-stroke electromagnetic actuators do not provide a constant force across the plunger position, making them unsuitable for applications requiring consistent linear motion.
Innovation Solution
The design incorporates a configuration with permanent magnets, non-ferromagnetic materials, and ferromagnetic cores with specific slot and winding arrangements, ensuring constant force delivery regardless of plunger position by optimizing the interaction between the magnets, cores, and windings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a current is applied to a winding surrounding a permanent magnet, then the magnet moves to deliver linear motion, but the force provided is dependent on the location of the magnet relative to the winding and is not constant
Solution Approach 1:
The actuator is divided into multiple independent coil assemblies, each with its own permanent magnet and ferromagnetic core. This segmentation allows each unit to generate constant force independently, and multiple units can be combined to achieve higher forces while maintaining constant force characteristics throughout the stroke.
Solution Approach 2:
The coil assemblies are positioned asymmetrically relative to the plunger, with each coil oriented at a different angle. This asymmetric arrangement creates a balanced magnetic field that produces constant force regardless of plunger position, eliminating the force variation problem in conventional actuators.
2Force
If permanent magnets and ferromagnetic cores are used to achieve constant force, then force consistency is improved, but the device complexity increases
Solution Approach 1:
Multiple coil assemblies with permanent magnets and ferromagnetic cores are merged into a single integrated actuator unit. The ferromagnetic cores are positioned to work together, creating a unified magnetic circuit that maintains constant force while reducing the overall complexity compared to using separate actuators.
Solution Approach 2:
The magnetic field interaction is extended into the angular dimension by orienting coils at different angles around the plunger. This three-dimensional arrangement of coils and magnets creates a more uniform magnetic field that maintains constant force, transforming a one-dimensional problem into a multi-dimensional solution.
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 maintains a constant force of 160 N across a 4 mm displacement range, providing consistent linear motion suitable for applications like fuel valve control.
Implementation Method 1
Application of a current causes the magnet to move and this motion, in turn, causes a plunger attached to the magnet to move to deliver linear motion
Implementation Method 2
The actuator includes a plunger, two ferromagnetic cores, and two windings. The ferromagnetic cores are disposed on opposite sides of the plunger
Implementation Method 3
A non-ferromagnetic material is disposed between the permanent magnets
Data Source
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AI summary
An electromagnetic actuator (100) includes first winding and second windings passing through a first core and a second core, respectively. The first and second cores are arranged such that the first and second core slots form a gap their respective cores between the first and second windings and the first and second permanent magnets and the first and second core slots have a slot opening width (a), the first and second magnets have a magnet height (h) measured along the central axis that the first and second cores have a core height (H) measured along the central axis and h > a; H> h; and H-h < 0.5H.