Thermoelastic Actuator with Parallel Elements for Compact Rotary Motion
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Solution Overview
Problem
Thermoelastic actuators with traditional designs are not compact due to the required length of the thermoelastic actuator elements, limiting their application in various devices.
Innovation Solution
A thermoelastic actuator with an antagonistic actuator unit comprising two parallel thermoelastic actuator elements connected to a carriage element, where one element's contraction moves the carriage while the other stretches, allowing for a compact design and high actuating force through electrical control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional thermoelastic actuator designs are used, then the actuator can provide the required actuating force, but the actuator becomes non-compact and cannot be used in various applications due to size constraints
Solution Approach 1:
The patent transitions from a linear arrangement of thermoelastic elements to a radial configuration where multiple elements are arranged around a central axis. This dimensional reorganization allows the actuator to achieve compact radial symmetry while maintaining the necessary actuating force through the combined effect of multiple elements working in parallel.
Solution Approach 2:
Multiple thermoelastic actuator elements are merged into a single integrated radial structure where they share common mounting points and work together on a single carriage element. This merging reduces the overall volume by eliminating redundant structural components while the combined force output of all elements maintains the required actuating capability.
2Length of moving object
If the length of thermoelastic actuator elements is increased to provide sufficient actuating force, then the actuator becomes non-compact, but reducing the length decreases the actuating force
Solution Approach 1:
The patent employs a composite structural arrangement where multiple thermoelastic elements are configured in parallel rather than relying on a single long element. This composite structure allows each element to be shorter while the collective force output matches or exceeds that of a single long element, achieving both compactness and sufficient actuating force.
Solution Approach 2:
The radial arrangement of elements creates a balanced force distribution around the central axis, where elements are positioned to counterbalance each other and work synergistically. This configuration maximizes the force output per unit length by ensuring all elements contribute effectively to the actuating motion without requiring excessive 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 actuator achieves a compact and robust design with high cycle durability, enabling applications in devices requiring rotary motion.
Implementation Method 1
A corresponding electric current is passed through the entire extension of the respective actuator element. The heating causes a contraction
Implementation Method 2
thermoelastic material (also referred to as elastocaloric or mechanocaloric material), e.g., a shape memory alloy, which undergoes a shape change upon temperature change
Data Source
AI summary
The invention relates to a thermoelastic actuator (1) for providing a rotary actuating motion, comprising:an actuating element (4) for outputting the rotatory actuating motion;an antagonistic actuator unit (2) coupled with the actuating element (4) to convert a translational movement into the rotary actuating motion;wherein the antagonistic actuator unit (2) comprises:at least two electrically separately activatable thermoelastic actuator elements (21, 21a, 21b), each extending in an extension direction (R) from a first end to a second end and arranged parallel to each other;a carriage element (24), which is movably guided in the direction (R), where the thermoelastic actuator elements (21, 21a, 21b) are each connected at the second end to the carriage element (24), so that upon a change of shape upon activation of one of the actuator elements (21, 21a, 21b), a pulling force is exerted on the carriage element (24) to translationally move the carriage element (24);an electrical connection between the first ends of the actuator elements (21, 21a, 21b) connected to the carriage element (24), so that a common electrical potential is applied to the actuator elements (21, 21a, 21b) via the carriage element (24).