Linear Actuator Using Shape Memory Alloy
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Solution Overview
Problem
Current actuator devices face limitations in optimizing volume, technical complexity, cost, precision, reliability, versatility, and actuation capacity, particularly due to high vibration, electromagnetic noise sensitivity, and restricted temperature ranges, making them unsuitable for high-precision and aerospace applications.
Innovation Solution
A compact linear actuator device utilizing a shaft aligned axially within a casing, actuated by elastic means and supported by intermediate elements, which allows for remote retention and deployment, featuring a shape memory alloy (SMA) actuator for high-temperature operation and reduced electromagnetic noise, enabling versatile and reliable actuation with minimal components and low shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If explosive or pyrotechnic devices are used for actuation, then minimum volume/weight ratio and instantaneous operation are achieved, but handling, storage, and maintenance problems arise along with hazardous materials and high impact/vibration levels
Solution Approach 1:
The patent replaces explosive/pyrotechnic mechanical systems with a shape memory alloy (SMA) actuator system. The SMA actuator uses thermal-mechanical coupling to produce linear displacement, eliminating hazardous explosive materials while maintaining compact size. The elastic means (spring) provides the actuation force without creating high impact or vibration levels associated with explosive devices.
Solution Approach 2:
The patent changes the actuation parameter from chemical explosion to thermal-mechanical phase transition of shape memory alloy. The SMA material undergoes a reversible phase transformation between austenite and martensite structures when heated or cooled, producing controlled linear displacement without the harmful effects of explosive materials.
2Object-affected harmful factors
If non-explosive actuator devices are used, then safety conditions improve and reusability is enabled, but volume/weight ratio increases compared to explosive devices
Solution Approach 1:
The patent employs a composite actuation system combining shape memory alloy (providing safety and reusability) with elastic means/springs (providing actuation force). This composite approach maintains safety advantages of non-explosive devices while optimizing the volume/weight ratio through the compact SMA element and efficient elastic storage mechanism.
3Force
If electromagnetic actuators are used, then optimal force/mass ratio and multiple actuations are achieved, but electromagnetic noise is generated which limits precision applications
Solution Approach 1:
The patent replaces electromagnetic actuators with a shape memory alloy actuator system. The SMA-based mechanical actuation produces force through thermal-mechanical phase transition without generating electromagnetic noise, enabling use in precision applications while maintaining optimal force/mass ratio through the compact design.
4Manufacturing precision
If piezoelectric actuators are used, then high force and precision are achieved, but stroke is limited to nanometers which restricts application versatility
Solution Approach 1:
The patent uses a dynamic system combining shape memory alloy actuation with elastic means to achieve both precision and extended stroke. The SMA provides precise controlled displacement through phase transition, while the elastic spring mechanism amplifies and extends the total stroke distance, overcoming the nanometer limitation of piezoelectric actuators.
5Reliability
If current actuator devices are optimized for one parameter, then that parameter improves, but other parameters such as temperature range, vibration sensitivity, and electromagnetic noise resistance deteriorate
Solution Approach 1:
The patent creates a universal actuator system using shape memory alloy that can operate across diverse conditions. The SMA material inherently provides broad temperature range operation, vibration resistance through solid-state phase transition, and electromagnetic noise immunity by being non-electromagnetic, enabling single-device optimization for multiple parameters simultaneously.
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 device achieves simultaneous optimization of design variables, ensuring high reliability, reusability, and compatibility with high-temperature environments while minimizing weight and electromagnetic interference, thus addressing the limitations of existing actuator technologies.
Implementation Method 1
shape memory alloy (SMA) actuator
Implementation Method 2
phase change, no they are extremely sensitive to environmental conditions
Implementation Method 3
actuating elastic means
Data Source
AI summary
The invention relates to a linear actuator device comprising a shaft (1) which can be displaced with respect to a casing (3), where said shaft (1) can be located in a first position in which it is actuated by elastic means (4), being maintained immobile by contact with a support element (5) which conveys its load to an intermediate element (6) which in turn conveys its load to an activating element (7); the shaft (1) being able to be located in a second position, in which the activating element (7) is rotated with respect to its position in the first position, such that said intermediate element (6) is housed in a housing (8) which the activating element (7) has, which allows displacing the support element (5) such that the shaft (1) is not in contact with said support element (5).