Strain Wave Gear Coupling for Flex Spline Fatigue Relief
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Solution Overview
Problem
Strain wave gearing systems experience increased fatigue and wear due to non-uniform deformation of the flex spline, which can lead to reduced durability and lifetime.
Innovation Solution
The strain wave gearing system incorporates a coupling element with a second mating element and a flex spline with a first mating element, allowing for radial movement of the first mating element relative to the second mating element, thereby preventing rotational motion and allowing deformation of the flex spline without transferring stresses to the coupling element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the length of the flex spline is increased to reduce wear, then the durability is improved, but the volume of the system increases
Solution Approach 1:
The flex spline is segmented into multiple sections with different wall thicknesses. The first section has a first wall thickness while the second section has a second wall thickness that is greater than the first. This segmentation allows the flex spline to achieve sufficient durability through strategic thickening at critical sections without requiring an overall increase in length, thus maintaining compact system volume.
Solution Approach 2:
The flex spline exhibits local quality variations in its wall thickness distribution. Specifically, the wall thickness is increased at the second section where wear and fatigue are more critical, while the first section maintains a thinner wall. This localized reinforcement improves durability at critical stress points without proportionally increasing the overall volume of the flex spline.
2Strength
If the wall thickness of the flex spline is increased to reduce fatigue, then the strength is improved, but the ability to deform elastically is reduced
Solution Approach 1:
The flex spline employs non-uniform wall thickness distribution where the first section has a thinner wall (first thickness) and the second section has a thicker wall (second thickness greater than first). This local quality variation allows the thinner first section to deform more easily under wave generator action, maintaining elastic deformation capability, while the thicker second section provides enhanced strength and fatigue resistance where structural integrity is critical.
Solution Approach 2:
The flex spline is divided into functional segments with different thickness characteristics. The first section is optimized for flexibility and deformation, while the second section is optimized for strength and wear resistance. This segmentation resolves the contradiction by allowing each section to perform its specialized function without compromising the other.
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 configuration reduces wear and fatigue on the flex spline, enhances the durability and lifetime of the strain wave gearing system, and allows for a more compact design by minimizing the length of the flex spline required for deformation.
Implementation Method 1
The side walls of the flex spline are relatively thin, allowing an open end of the flex spline to deform elastically when fit over a wave generator assembly
Data Source
AI summary
A strain wave gearing system is includes: wave generator; a rigid spline; a flex spline disposed between the wave generator and the rigid spline; and a coupling element. The flex spline comprises a first mating element. The coupling element comprises a second mating element. The coupling element and the flex spline are mated by cooperation of the first mating element and the second mating element so as to prevent rotational motion of the flex spline relative to the coupling element. The first mating element is movable relative to the second mating element to thereby permit deformation of the flex spline relative to the coupling element.