Harmonic Drive Tooth Profile Optimization for Lower Meshing Friction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Harmonic drives suffer from reduced efficiency due to friction between teeth during meshing, with existing optimization approaches yielding mixed results and efficiencies typically below 90%, making it difficult to achieve consistent high efficiencies due to manufacturing variances.
Innovation Solution
An optimized harmonic drive design featuring a wave generator with a minimized velocity profile, a flex spline with matching tooth contours, and a circular rigid spline with additional teeth, utilizing a non-linear involute curve generation process to minimize velocity profiles and reduce frictional losses during high load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional harmonic drive tooth profiles are used, then the structure is simple and easy to manufacture, but frictional losses are high and efficiency is low (typically below 90%)
Solution Approach 1:
The patent applies parameter changes by modifying the tooth profile geometry parameters, specifically using a non-linear involute curve generation process with optimized pressure angles and tooth spacing. This changes the physical parameters of the tooth profiles to minimize velocity profiles during meshing, thereby reducing frictional losses and improving efficiency while maintaining manufacturability through systematic parameter optimization.
Solution Approach 2:
The patent applies dynamics by transitioning from static tooth profile designs to dynamic optimization where the tooth profiles are designed to minimize velocity profiles during the meshing process. The non-linear involute curve generation process dynamically adjusts the tooth geometry based on operational conditions, allowing the system to adapt its mechanical interaction to reduce frictional losses during actual operation.
2Loss of energy
If tooth profiles are optimized to reduce friction, then efficiency improves, but manufacturing precision requirements increase due to sensitivity to variances
Solution Approach 1:
The patent applies self-service by designing tooth profiles with self-aligning characteristics where the non-linear involute curves automatically compensate for minor manufacturing variances during meshing. The optimized geometry allows the teeth to self-adjust their contact patterns, reducing sensitivity to precision errors and maintaining low frictional losses even with typical manufacturing tolerances.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating built-in geometric compensation in the tooth profiles that anticipates and cushions against manufacturing variances. The non-linear involute curve generation process pre-adjusts the tooth geometry to accommodate expected tolerance ranges, ensuring consistent performance and low frictional losses without requiring ultra-precise manufacturing.
3Loss of energy
If the velocity profile is minimized during high load conditions, then frictional losses are reduced and efficiency increases, but the complexity of the wave generator contour increases
Solution Approach 1:
The patent applies segmentation by dividing the wave generator contour into discrete segments or zones, each optimized for specific operational conditions. The non-linear involute curve generation process divides the tooth profile and wave generator geometry into manageable segments that can be independently optimized, reducing the overall complexity while maintaining the minimized velocity profile characteristic during high load conditions.
Data Source
AI summary
An optimized harmonic drive (“OHD”) includes a wave generator, a flex spline, and a circular rigid spline. The wave generator includes a wave generator contour that minimizes a velocity profile of the wave generator during a high load condition. The flex spline is attached to the wave generator and the circular rigid spline is mechanically engaged to the flex spline. The flex spline includes a plurality of flex spline teeth and the circular rigid spline includes a plurality of rigid spline teeth. The plurality of rigid spline teeth is greater than the plurality of flex spline teeth and the high load condition exists when the rigid spline teeth of the plurality of rigid spline teeth are fully engaged with flex spline teeth of the plurality of flex spline teeth.