Actuator Using Electromagnetic Reset for Expanded MSM Stroke
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Solution Overview
Problem
Magnetic Shape Memory (MSM) actuator devices have limited usable stroke and require additional hardware and complexity for resetting, as they often rely on mechanical or magnetic springs that restrict the maximum expansion stroke and require high actuation force.
Innovation Solution
A push-push actuator system is developed using a single MSM system with independently controllable actuating means, where the first actuating means is magnetically active and the second is electromagnetically or piezoelectrically powered, allowing for a maximum expansion stroke of at least 90% without opposing forces, and utilizing mechanical or permanent magnet means for resetting with low restoring force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical spring is used as restoring means to reset the MSM crystal, then the actuator can return to its initial position, but the maximum expansion stroke is limited to about 80% of the possible maximum expansion stroke
Solution Approach 1:
The patent removes the mechanical spring from the system entirely. Instead of using a spring to provide restoring force, the invention uses a second electromagnet that can be independently controlled to actively pull the armature back to its initial position. This extraction of the spring eliminates the force-displacement constraint that limited the expansion stroke to 80%.
Solution Approach 2:
The patent replaces the mechanical spring-based restoring mechanism with an electromagnetic system. The second electromagnet generates magnetic force to reset the armature, substituting the mechanical elastic force of the spring with controllable electromagnetic force. This allows the system to achieve full expansion stroke while maintaining reliable returnability through active electromagnetic control.
2Ease of operation
If the actuating force of the shape memory alloy material is set to exceed the restoring force of the spring for expansion, then expansion movement can occur, but the usable stroke is limited due to the linearly increasing spring force
Solution Approach 1:
The patent makes the restoring force dynamic and controllable through the second electromagnet. Instead of a static spring force that linearly increases with displacement, the electromagnetic restoring force can be adjusted independently at different positions along the stroke, allowing full utilization of the expansion capability without being constrained by a fixed force-displacement relationship.
Solution Approach 2:
The patent changes the parameter of restoring force from a fixed mechanical property (spring constant) to a controllable electromagnetic parameter. By independently controlling the current in the second electromagnet, the restoring force can be varied to match the actuating force at each position, enabling the system to achieve maximum expansion stroke while maintaining ease of operation throughout the full range of motion.
3Device complexity
If two MSM actuators are mechanically coupled in a push-push system, then resetting is achieved without springs, but the hardware and component expenditure increases considerably
Solution Approach 1:
The patent makes the second electromagnet multi-functional: it serves both as the restoring mechanism (pulling the armature back) and as part of the actuation system. This single component performs multiple functions, eliminating the need for separate MSM actuators dedicated to resetting, thereby reducing hardware expenditure while maintaining resetting capability.
Solution Approach 2:
The patent merges the resetting function with the electromagnetic actuation system. Instead of using separate MSM actuators for expansion and resetting, the invention combines both functions into a single electromagnetic system with two independently controllable electromagnets, reducing the overall quantity of components while achieving the push-push effect.
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 design enhances the usable expansion stroke and simplifies the actuator system, enabling reliable returnability to the starting position with reduced hardware complexity and increased efficiency in actuation and movement behavior.
Implementation Method 1
an MSM (FGL) crystal body (as a representative for a large number of possible MSM-based materials), typically produced on the basis of a NiMnGa alloy, is exposed to a magnetic field generated by an energized coil. In response to such a magnetic field being applied, the MSM crystal body, as the expansion body or expansion means, performs an expansion movement
Implementation Method 2
a second actuating means (20), in particular an electromagnetic actuator, which has a coil arrangement (22) and a yoke core arrangement (26)
Implementation Method 3
those with the first adjusting means via the Although the second actuating means connected to or interacting with the actuating body are initially designed to be electrically powered and activated (or acted upon by an electrical signal), they do not have any magnetically effective shape memory alloy material
Data Source
Figure 1~4
AI summary
The invention relates to an actuator device for bidirectionally adjusting an actuating element, preferably in the form of a tappet, which is designed to interact with an actuating partner, comprising first actuating means with expansion means which have a magnetically active shape-memory alloy material and exert an actuating force, in particular a pushing force, on said actuating element in order to move the actuating element along a first adjusting direction, said expansion means carrying out an expansion that generates the actuating force in response to a first supply of current to first coil means, and comprising second actuating means which are paired with the actuating element and which are provided separately from the expansion means and the first coil unit, said second actuating means being designed to move the actuating element in a second adjusting direction opposite the first adjusting direction. According to the invention, the second actuating means form a drive which can be activated in response to an applied signal, in particular a second electric current supply, in order to move the actuating element in the second adjusting direction, said drive not having an expansion unit which interacts with the actuating element and which is made of a magnetically active shape-memory alloy material.