Electrodynamic Actuator Air-Core Coil Miniaturization
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Solution Overview
Problem
Electromagnetic actuators in miniaturized fluid valve technology face challenges in achieving sufficient magnetic force while saving space, as the magnetic field strength decreases with smaller coils, limiting their effectiveness in miniature applications.
Innovation Solution
An electrodynamic actuator with an air-core coil firmly coupled to a nonmagnetic coil carrier, utilizing the Lorentz force for actuation, which maintains force consistency across stroke lengths and allows for compact designs suitable for microvalves and micropumps, featuring a magnet arrangement with permanent magnets and a restoring element for preload and electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the coil size is reduced to achieve miniaturization, then the device size is reduced, but the magnetic field strength and available force greatly decrease
Solution Approach 1:
The patent replaces the traditional electromagnetic actuator mechanism (coil generating magnetic field to move armature) with an electrodynamic actuator mechanism (permanent magnets generating magnetic field, air-core coil generating Lorentz force). This substitution allows the force to be independent of coil size, enabling miniaturization without force loss.
Solution Approach 2:
The patent changes the fundamental operating parameters by using permanent magnets instead of electromagnets for field generation, and using an air-core coil instead of a traditional wound coil with magnetic core. This parameter change transforms the force-generation mechanism from magnetic field strength-dependent to Lorentz force-dependent, where force depends on current intensity, magnetic field strength, and coil-magnet distance rather than coil size.
2Area of stationary object
If the coil size is reduced to save space, then the device becomes more compact, but the maximum possible current is limited
Solution Approach 1:
The patent replaces the electromagnetic field generation system with an electrodynamic system using permanent magnets and air-core coils. This substitution removes the limitation where smaller coils cannot carry sufficient current, as the Lorentz force mechanism allows effective force generation with smaller coils carrying appropriate currents.
3Volume of moving object
If traditional electromagnetic actuators are used for miniaturization, then device size is reduced, but force transmission decreases as stroke decreases
Solution Approach 1:
The patent changes the force-generation parameters by using the Lorentz force equation (F = BIL) where force depends on magnetic field strength B, current I, and conductor length L in the magnetic field. By maintaining constant distance between the air-core coil and permanent magnets, the magnetic field strength remains constant throughout the stroke, ensuring consistent force transmission independent of stroke length.
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 electrodynamic actuator achieves powerful, consistent force transmission with large strokes, enabling small overall sizes, cost-effective manufacturing, reduced tolerance issues, and quiet operation, suitable for both on/off and proportional valves without design changes, and can be used in compact microvalve and micropump applications.
Implementation Method 1
the Lorentz force can be utilized as a drive force for an actuator if the control element of the actuator includes a coil which is arranged in a magnetic field and to which a current is applied for deflection of the control element
Data Source
AI summary
An electrodynamic actuator, in particular for a microvalve or a micropump, includes a magnet arrangement for generating a magnetic field and a control element movable relative to the magnet arrangement. The control element includes an energizable air-core coil (22) which is arranged in the magnetic field and firmly coupled to a coil carrier (20) made from a nonmagnetic material.