Planar Torsional Spring Structure for Linear Torque Response
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Solution Overview
Problem
Existing planar torsional springs face challenges in achieving linear response, ease of modeling, and versatility due to issues like asymmetry, radial stresses, and inefficient stress balance, particularly in compact mechanical designs such as wearable robotics, where they often require a compromise between performance and dimensions.
Innovation Solution
A planar torsional spring design featuring a unitary body with a beam-shaped pattern and serpentine linking portions between main radial members, eliminating the need for rings and ensuring balanced stress distribution by connecting the torsional load at radially external or internal locations equally distant from the central axis, allowing for easier modeling and improved rigidity calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known planar torsional spring configurations are used, then the spring can transmit torsional load, but the response is non-linear and modeling is difficult due to asymmetry and radial stresses
Solution Approach 1:
The patent applies asymmetry principle by designing a planar torsional spring with asymmetric geometry where the neutral axis is intentionally offset from the centerline. This asymmetric configuration balances the tensile and compressive stress distributions, enabling linear elastic response and simplifying modeling while maintaining compact dimensions.
2Volume of moving object
If compact dimensions are used for wearable robotics, then the overall size is reduced, but the stress balance deteriorates and performance compromises
Solution Approach 1:
The patent applies local quality principle by varying the cross-sectional properties and thickness distribution at different locations along the spring body. The asymmetric thickness profile and localized geometric features are optimized to balance stresses in compact dimensions, allowing the spring to maintain linear response and reliable performance while minimizing overall size for wearable applications.
3Force
If radial evolving elements are used to join inner and outer rings, then torsional load is transmitted, but the design requires many heterogeneous quantities reducing modeling efficiency
Solution Approach 1:
The patent applies merging principle by integrating the inner and outer rings into a single monolithic planar body with a continuous asymmetric cross-section. This unified structure eliminates the need for separate radial evolving elements and multiple heterogeneous design parameters, simplifying the model to require fewer parameters while maintaining effective torsional load transmission through the asymmetric geometry.
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 design provides a more linear and balanced torsional response, enhanced modeling accuracy, and increased versatility, enabling efficient torque transmission with reduced dimensions and weight, suitable for applications in wearable robotics and other elastic actuators.
Implementation Method 1
The body (1) is arranged and connected between such elements as to elastically react to a torsional stress applied around a transmissive axis (Z)
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5b
AI summary
The object of the present invention is a new configuration of torsional spring with a flat structure, capable of ensuring response linearity, modelling ease and accuracy, versatile use while safeguarding the possibility of the inner passage of wiring or of any accessory components along the transmission/torsion axis.