Circular Wave Drive Speed Reduction Mechanism
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Solution Overview
Problem
Current power transmission and speed reduction devices, such as harmonic and cycloidal drives, suffer from material fatigue, complex construction, non-backdrivability, and vibration issues, limiting their performance and lifespan.
Innovation Solution
The circular wave drive mechanism, featuring a compact housing with a toothed inner wall, a ring-shaped wheel, and an oval-shaped wave generator, provides a simpler and more efficient speed reduction system with low friction and adjustable speed reduction ratios through sliding motion and tooth engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a harmonic drive is used to achieve high speed reduction ratio and high positional accuracy, then the speed reduction ratio and accuracy are improved, but the flexspine material fatigues due to continual elastic deformation, limiting the torque transfer and lifespan
Solution Approach 1:
The patent extracts the problematic flexspine component from the system and replaces it with a rigid output gear. The elliptical wave generator directly drives the output gear through tooth engagement, eliminating the flexible element that was subject to fatigue while maintaining the speed reduction function.
Solution Approach 2:
The invention uses standard rigid gear materials instead of specialized flexible steel, effectively replacing a durable but complex flexible component with simpler, more reliable rigid components that don't suffer from fatigue.
2Productivity
If a cycloidal drive is used to achieve speed reduction, then the speed reduction is achieved, but the construction becomes complex with multiple components including cycloidal disc, ring pins, and output rollers
Solution Approach 1:
The patent merges the cycloidal motion generation and power transmission functions into a single integrated mechanism. The elliptical wave generator simultaneously creates the cycloidal motion and engages the output gear, eliminating the need for separate ring pins, cycloidal discs, and output rollers.
Solution Approach 2:
The elliptical wave generator serves multiple functions: it generates the cycloidal motion, provides the driving force, and directly engages the output gear. This multi-functional component replaces several specialized components in traditional cycloidal drives.
3Productivity
If a cycloidal drive is used to achieve speed reduction, then the speed reduction is achieved, but the eccentric rotation produces vibration that may be transmitted through the shafts
Solution Approach 1:
The patent extracts the source of vibration by eliminating the eccentric bearing and offset shaft configuration. The elliptical wave generator is centrally mounted and rotates concentrically with the output gear, removing the mechanism that generated harmful vibrations while preserving the cycloidal motion through the elliptical geometry of the wave generator itself.
4Productivity
If a cycloidal drive is used to achieve speed reduction, then the speed reduction is achieved, but the contact between output rollers and receiving holes leads to wear of both components
Solution Approach 1:
The invention replaces the wear-prone roller-and-hole contact mechanism with standard gear tooth engagement. The output gear uses conventional gear materials and tooth profiles that are designed for durability and can be easily replaced if needed, rather than the specialized cycloidal disc with receiving holes.
Solution Approach 2:
The patent changes the contact mechanism from point/line contact (rollers in holes) to surface contact (gear tooth flanks). This parameter change in the nature of contact significantly reduces stress concentration and wear on the components.
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 circular wave drive achieves high speed reduction ratios with minimal backlash and vibration, offering a more durable and simplified design compared to existing technologies.
Implementation Method 1
The wave generator will typically have an input shaft portion and a wheel-driving portion. The wheel-driving portion of the wave generator may be oval-shaped or of truncated circle shape in cross-section, and the input shaft portion is offset from the central axis of the wheel-driving portion so as to impart an eccentric motion thereto when rotated.
Implementation Method 2
The wheel diameter is smaller than the chamber diameter, such that only a portion of the wheel teeth are meshed with the internal housing teeth at any given time. The wheel also includes teeth that are disposed along a portion of the inner wall thereof.
Implementation Method 3
Teeth are disposed along an inside circular wall of the chamber. A ring-shaped wheel with a hollow central portion resides within the chamber. The wheel includes external teeth that mesh with the teeth located along the circular inner wall of the housing.
Data Source
AI summary
Exemplary embodiments of the invention are directed to drive mechanisms that may be used in, for example, power transmission and/or speed reduction applications. Exemplary embodiments of the invention may include a housing within which is located a wheel. A portion of a wave generator and a portion of an output element also reside within the chamber and are in communication with the wheel. Rotation of the wave generator causes a rotation of the wheel in a slipping manner and, thus, with a reduced rotational speed. Rotation of the wheel causes a rotation of the output element.