Strain Wave Gearing with Switchable Speed Ratios
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Solution Overview
Problem
Existing strain wave gearings are limited to a fixed speed ratio, which restricts the flexibility in achieving multiple stages of speed reduction, limiting their application in various industrial uses where different torque and rotational speed requirements are needed.
Innovation Solution
A speed ratio switching type strain wave gearing is designed with an externally toothed gear, internally toothed gears, and a wave generator, along with a clutch mechanism, allowing the switching of internally toothed gears between rotation-enabled and fixed states to change the speed ratio by varying the number of teeth, enabling multiple stages of speed reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed speed ratio strain wave gearing is used, then the structure is simple, but the adaptability to different speed ratio requirements is poor
Solution Approach 1:
The externally toothed gear is segmented into multiple sets of external teeth (first external teeth, second external teeth, etc.) arranged at different axial positions. Each set of external teeth corresponds to a different speed ratio. By selectively engaging different sets of external teeth with internally toothed gears, the gearing can switch between multiple speed ratios without requiring multiple complete gear sets.
Solution Approach 2:
The externally toothed gear serves multiple functions by incorporating multiple sets of external teeth that can engage with different internally toothed gears. This single component performs the function of multiple gear ratios, eliminating the need for separate strain wave gearings for each speed ratio and enabling one rotation input to produce multiple rotation outputs at different speed ratios.
2Adaptability or versatility
If multiple strain wave gearings are provided to achieve two degrees of freedom rotation output, then the speed ratio versatility is improved, but the device complexity increases
Solution Approach 1:
Multiple strain wave mechanisms are merged into a single integrated structure. The externally toothed gear contains multiple sets of external teeth that can simultaneously or selectively engage with multiple internally toothed gears. This merging allows one rotation input to produce two or more rotation outputs at different speed ratios without requiring separate strain wave gearings for each output.
Solution Approach 2:
The patent transitions from a single-plane gear engagement to a multi-dimensional arrangement where multiple sets of external teeth are positioned at different axial locations on the externally toothed gear. This spatial arrangement in the axial dimension enables multiple gear engagements simultaneously, achieving multiple rotation outputs from one input without increasing the number of separate gearings.
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 allows for a compact and simple strain wave gearing that can switch the speed ratio of the rotation output to multiple levels, enabling flexible torque and rotational speed adjustments, enhancing its applicability in industrial robots and NC machinery.
Implementation Method 1
an externally toothed gear including a predetermined number of first external teeth formed on a cylindrical external peripheral surface capable of flexing in a radial direction
Data Source
AI summary
A speed ratio switching type strain wave gearing can switch the speed ratio of output rotation with respect to one input rotation into two states or multiple states with a simple configuration. The speed ratio switching type strain wave gearing includes first and second internally tooted gears, an externally toothed gear having first and second external teeth formed on the external peripheral surface thereof, a wave generator that causes the first and second external teeth to partially mesh with the first and second internally toothed gears, a clutch mechanism that can selectively switch the first and second internally toothed gears into a fixed state. Input rotation from the wave generator can be reduced in speed at a different speed ratio and derived from the externally toothed gear by selectively switching the first and second internally toothed gears into a fixed state.