MEMS Actuator Magnetic Latching for Compact Bistable Motion
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Solution Overview
Problem
Conventional electromechanical actuators are large, complex, and costly due to their construction requiring coil windings, and they often rely on mechanical latching which reduces reliability and increases size, whereas applications demand smaller, more efficient actuators with rapid movement and bistable latching capabilities.
Innovation Solution
The development of electromechanical actuators with planar circuitry and magnetic latching, utilizing a laminated design with ferromagnetic layers and coils, where magnetic latching at each end of the stroke is achieved without additional components, allowing for smaller size and reduced complexity, and using flexures to constrain motion and enhance actuation force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coil windings and mechanical latching are used, then actuator reliability is reduced and size increases, but actuator construction is simplified
Solution Approach 1:
The patent replaces mechanical latching mechanisms with magnetic latching. The armature includes a permanent magnet that provides magnetic latching force to hold the armature in the actuated position, eliminating the need for separate mechanical latching components. This substitution improves reliability by removing mechanical wear points while reducing overall device complexity through integration into the armature structure.
Solution Approach 2:
The patent combines the latching function with the armature structure itself. The permanent magnet is integrated directly into the armature, merging the latching mechanism with the moving component. This integration eliminates separate latching parts, reduces complexity, and improves reliability by creating a more unified and robust structure.
2Force
If mechanical latching components are added, then latching force increases, but actuator size increases
Solution Approach 1:
The patent replaces bulky mechanical latching components with a compact permanent magnet. The magnetic latching force is generated within the armature structure itself, providing strong holding force without requiring additional external latching mechanisms. This significantly reduces the actuator size while maintaining or improving latching force.
Solution Approach 2:
The patent changes the latching mechanism from mechanical to magnetic, fundamentally altering the physical parameter of how latching force is generated. The permanent magnet provides high latching force in a compact form factor, achieving superior force-to-size ratio compared to traditional mechanical latching components.
3Speed
If friction is reduced through design, then actuation speed increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent eliminates mechanical friction by replacing contact-based latching with magnetic latching. The permanent magnet provides holding force without physical contact, removing friction entirely from the latching interface. This allows for faster actuation speeds while the clearance requirements are managed through the magnetic field's tolerance to gaps.
Solution Approach 2:
The patent introduces the magnetic field as an intermediary between the armature and stator. Instead of direct mechanical contact for latching, the magnetic field mediates the interaction, allowing force transmission without physical contact. This eliminates friction while the magnetic field's nature provides tolerance to manufacturing variations in clearance.
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 results in smaller, more reliable, and cost-effective electromechanical actuators capable of rapid movement and bistable latching, with reduced friction and increased actuation speed, suitable for applications requiring compact size and high performance.
Implementation Method 1
Current flowing through the coil produces a magnetic field, causing the armature of the solenoid actuator to 'pull in'.
Implementation Method 2
magnetic latching at each end of the stroke is achieved without additional components
Implementation Method 3
The plunger assembly includes a permanent magnet and ferromagnetic plates
Data Source
AI summary
Introduced here is an electromechanical actuator that includes a stator assembly with a chamber partially defined therethrough along a central longitudinal axis and a plunger assembly that is situated in the chamber and, in operation, moves along the central longitudinal axis between different positions. The stator assembly can include a pair of contacts that have an opening therebetween and a trinity of ferromagnetic layers with coils situated therebetween. The plunger assembly can include a magnet. When current is applied to the coils, the trinity of ferromagnetic layers become magnetically polarized, thereby dictating the motion of the plunger assembly by magnetically attracting or repelling the magnet included in the plunger assembly. The plunger assembly may be stabilized by a flexure flexibly connecting the stator assembly and plunger assembly.