Harmonic Actuator Tooth Profile Mapping for Precise Gear Meshing
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Solution Overview
Problem
Existing harmonic gear systems in aircraft rotary actuators face challenges with mismatched tooth profiles between the flex spline and circular gear, leading to increased friction and reduced accuracy in motion control.
Innovation Solution
A method is developed to generate and adjust tooth profiles for the flex spline and circular gear by aligning and transforming mid-points between centroids, ensuring precise alignment and fitting with a tolerance of 1/10,000 of an inch, allowing for universal application across various diameters and numbers of teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional tooth profiles are used for flex spline and circular gear, then manufacturing is simpler, but meshing accuracy decreases and friction increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and establishing the optimal tooth profile geometry through centroid-based mapping before manufacturing. The method defines centroid locations on both flex spline and circular gear, then pre-determines the tooth profile shape that ensures precise meshing, eliminating the need for iterative adjustments during manufacturing and achieving high meshing accuracy from the first production run.
Solution Approach 2:
The patent implements parameter changes by transforming the tooth profile design from traditional standardized shapes to custom profiles defined by centroid mapping. Key parameters such as tooth thickness, tooth height, and profile curvature are adjusted based on the specific geometric relationship between the flex spline and circular gear centroids, optimizing meshing conditions for each particular gear configuration.
2Reliability
If precise tooth profile alignment is achieved through centroid mapping, then friction is reduced and meshing accuracy is improved, but the development process becomes more complex
Solution Approach 1:
The patent replaces complex mechanical trial-and-error adjustment processes with a mathematical and computational approach. Instead of physically prototyping and iteratively adjusting tooth profiles, the invention uses centroid-based geometric mapping and mathematical transformation to directly determine the optimal tooth profile, substituting mechanical experimentation with analytical calculation.
Solution Approach 2:
The patent applies copying by creating an idealized geometric model of the tooth profile through centroid mapping, then replicating this mathematically derived profile in the actual manufacturing process. The centroid-based mapping serves as a template or copy that ensures the physical tooth profiles will mesh accurately, transferring the precision of the mathematical model to the physical components.
3Adaptability or versatility
If universal tooth profile method is developed for various diameters and tooth counts, then adaptability is improved, but initial development time and complexity increase
Solution Approach 1:
The patent achieves universality by developing a generalizable centroid-based tooth profile mapping method that can be applied to any flex spline and circular gear combination. The approach uses fundamental geometric relationships (centroids, pitch circles, and mathematical transformation) that remain valid regardless of specific diameter or tooth count, allowing the same methodology to serve multiple different gear design scenarios.
Solution Approach 2:
The patent applies preliminary action by establishing a universal mathematical framework and set of procedural steps for tooth profile development that can be reused across different gear configurations. Once the centroid mapping methodology is initially developed, it serves as a reusable template that can be quickly adapted to various diameters and tooth counts without requiring redundant development work for each specific case.
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 method improves meshing accuracy and reduces friction, enabling precise and repeatable tooth profile development for harmonic actuators, enhancing the performance and reliability of aircraft motion control systems.
Implementation Method 1
The flex spline is thin and made of elastic metal with external or internal teeth formed along an outer or inner circumference thereof
Data Source
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AI summary
A method of developing a flex spline and circular gear tooth profile for a harmonic actuator is provided. The method includes defining circular gear and flex spline centroids (1004) based on gear ratio calculations, finding mid-points (1005) between the centroids of the circular gear and the centroids of the flex spline and transforming the mid-points (1005) into a mapping of the tooth profile for respective teeth of the circular gear and the flex spline.