Strain Wave Gearing Offset Wave Generator Support
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Solution Overview
Problem
Conventional flat strain wave gearings are not optimized in terms of mechanical properties and operating conditions, particularly with the arrangement of internally toothed gears and wave generators, leading to suboptimal performance in terms of tooth face abrasion and ratcheting torque.
Innovation Solution
The strain wave gearing is configured with a cylindrical externally toothed gear capable of radially flexing, where the support center of the wave generator is offset relative to the tooth-width center, allowing for improved meshing across the entire tooth-width direction, and the first and second internally toothed gears are arranged in parallel with a nominal gap, optimizing the arrangement to reduce abrasion or increase torque based on the offset position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the support center of the wave generator is positioned at the tooth-width center of the externally toothed gear, then the configuration is symmetrical and simple to manufacture, but the mechanical properties are not optimized leading to increased tooth face abrasion and reduced ratcheting torque
Solution Approach 1:
The patent applies asymmetry by offsetting the support center of the wave generator from the tooth-width center of the externally toothed gear. This asymmetric positioning optimizes the meshing characteristics between gears, reducing tooth face abrasion and enhancing ratcheting torque. The offset creates a more favorable load distribution across the tooth faces during operation.
2Reliability
If the support center of the wave generator is offset from the tooth-width center, then tooth face abrasion is reduced and ratcheting torque is increased, but the configuration becomes more complex
Solution Approach 1:
The patent applies local quality by selectively offsetting only the support center position of the wave generator relative to the tooth-width center, while maintaining other symmetrical aspects of the gear system. This localized modification optimizes meshing characteristics without requiring complete redesign of the entire gear assembly, thus balancing performance improvement with manufacturing complexity.
3Reliability
If the first and second internally toothed gears are arranged with optimal spacing, then meshing performance is improved, but the structural simplicity is reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the spacing and positioning parameters of the first and second internally toothed gears relative to the externally toothed gear. By adjusting these geometric parameters, the meshing performance is enhanced, achieving better load distribution and reduced abrasion, while the overall structural complexity remains manageable.
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 tooth face abrasion when the support center is offset towards the drive-side gear and increases ratcheting torque when offset towards the stationary-side gear, while maintaining mechanical strength by adjusting the offset within a 1-4% range of the pitch diameter.
Implementation Method 1
a cylindrical flexible externally toothed gear (4) arranged inside the first and second internally toothed gears (2, 3), the flexible externally toothed gear (4) being capable of meshing with each of the first and second internally toothed gears (2, 3)
Data Source
AI summary
A flat strain wave gearing device equipped with: a first internal gear and a second internal gear; a flexible tubular external gear; and an elliptically shaped wave generator. In the direction of a central axis, the center of support of the external teeth by the wave generator is offset, by an offset amount of Δ along the direction of the central axis, with respect to the tooth-width center of the external teeth of the external gear. By setting the offset direction and the offset amount appropriately it is possible to achieve a strain wave gearing device which is suitable in terms of the operating conditions and the mechanical characteristics of the first and second internal gears.