Strain Wave Gear Coupling That Frees Flex Spline Deformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Strain wave gearing systems experience increased fatigue and wear due to non-uniform deformation of the flex spline, leading to reduced durability and lifetime, and there is a need for a more compact design.
Innovation Solution
A strain wave gearing system with a flex spline and a coupling element mated by cooperation of first and second mating elements, allowing radial movement of the flex spline relative to the coupling element, preventing rotational motion and transferring torque while minimizing stress transfer to the coupling element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flex spline is allowed to deform freely to reduce fatigue, then durability is improved, but torque transfer to the coupling element deteriorates
Solution Approach 1:
The coupling element is segmented into multiple teeth that engage with corresponding teeth on the flex spline. This segmentation allows localized torque transfer at discrete engagement points while permitting overall deformation of the flex spline body, resolving the contradiction between free deformation for durability and torque transfer for power transmission.
Solution Approach 2:
The flex spline is designed with varying wall thickness along its length, with thicker sections at engagement points for robust torque transfer and thinner sections for flexible deformation. This local quality variation enables the spline to be rigid where needed for power transmission and flexible where needed for fatigue reduction.
2Reliability
If the flex spline length is increased to reduce wear, then durability is improved, but system volume increases
Solution Approach 1:
The flex spline is constructed from composite materials with optimized mechanical properties, combining high strength-to-weight ratio and wear resistance. This allows the use of a shorter spline length while maintaining durability and wear resistance, thereby reducing system volume without sacrificing reliability.
3Stability of the object's composition
If the flex spline is constrained to prevent rotation relative to coupling element, then rotational stability is improved, but deformation capability deteriorates
Solution Approach 1:
The constraint mechanism between the flex spline and coupling element is designed to be dynamic rather than rigid. The teeth engagement provides rotational stability through positive mechanical coupling, while the elastic properties of the flex spline material allow dynamic deformation during operation. This dynamic constraint maintains rotational stability while preserving deformation capability.
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 system reduces wear and fatigue of the flex spline by allowing it to deform without transferring stresses to the coupling element, enhancing durability and enabling a more compact design.
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
Implementation Method 2
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
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A strain wave gearing system (100) is provided comprising a wave generator (110); a rigid spline; a flex spline (120) disposed between the wave generator (110) and the rigid spline; and a coupling element (130). The flex spline (120) comprises a first mating element (124). The coupling element (130) comprises a second mating element (132). The coupling element (130) and the flex spline (120) are mated by cooperation of the first mating element (124) and the second mating element (132) so as to prevent rotational motion of the flex spline (120) relative to the coupling element (130). The first mating element (124) is movable relative to the second mating element (132) to thereby permit deformation of the flex spline (120) relative to the coupling element (130).