Strain Wave Gear Ratio Switching With Selective Clutch Fixing
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Solution Overview
Problem
Existing strain wave gearings are limited to a single fixed speed ratio, restricting maximum torque and rotational speed, and require multiple gearings for different applications, leading to inefficiencies and increased costs.
Innovation Solution
A speed ratio switching type strain wave gearing with a flexible externally toothed gear and multiple internally toothed gears, utilizing a clutch mechanism to selectively disable and enable toothed gears for varying speed ratios, allowing two or more stages of output speed adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single strain wave gearing is provided per motor with a fixed speed ratio, then the maximum torque and maximum rotational speed are determined at a certain level, but the versatility and adaptability for different applications are reduced
Solution Approach 1:
The patent implements a single strain wave gearing unit that can operate at multiple speed ratios by incorporating two internally toothed gears (first and second) that can selectively engage with the externally toothed gear. The clutch mechanism enables this gearing to provide different reduction ratios (first speed ratio when first internally toothed gear engages, second speed ratio when second internally toothed gear engages), making one gearing unit universal for multiple applications instead of requiring separate gearings for each speed ratio requirement.
Solution Approach 2:
The patent employs a dynamic switching mechanism (clutch) that can change the engagement state between the wave generator and the two different internally toothed gears based on operational requirements. This dynamic reconfiguration allows the system to transition between different speed ratios during operation, transforming a static single-ratio gearing into a dynamic multi-ratio system without changing the physical structure of the strain wave gearing itself.
2Adaptability or versatility
If multiple strain wave gearings are provided to achieve different speed ratios, then speed ratio versatility is improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges the functionality of multiple separate strain wave gearings into a single integrated gearing unit. By combining two internally toothed gears (first and second) within one externally toothed gear assembly and using a common wave generator, the system achieves what would otherwise require two separate gearings, thereby reducing the quantity of components while maintaining multiple speed ratio capabilities.
Solution Approach 2:
The single strain wave gearing unit is designed to perform multiple functions by selectively engaging different internally toothed gears. This multi-functional design eliminates the need for multiple dedicated gearings, reducing both the number of components and the overall system complexity while providing versatile speed ratio options.
3Ease of operation
If the speed ratio is fixed, then the gearing structure is simple, but the ability to adjust torque and rotational speed output is limited
Solution Approach 1:
The patent introduces a clutch mechanism as an intermediary component that mediates between the wave generator and the two internally toothed gears. This clutch acts as a switching device that can selectively connect the wave generator to either the first internally toothed gear or the second internally toothed gear, enabling speed ratio adjustment without directly modifying the strain wave gearing structure itself. The clutch serves as a control intermediary that adds operational flexibility with minimal structural complexity.
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
Enables flexible speed ratio adjustment with minimal mechanical stress, reducing complexity and cost by allowing a single gearing to operate at multiple performance levels, enhancing torque and rotational speed versatility.
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
Figure 1(a)~1(b)
Figure 2~3
Figure 4
AI summary
A speed ratio switching type strain wave gearing (1) can switch the speed ratio of output rotation with respect to one input rotation 5into two states or multiple states with a simple configuration. The speed ration switching type strain wave gearing (1) includes first and second internally tooted gears (2, 3), an externally toothed gear (4) having first and second external teeth (45, 46) formed on the external peripheral surface thereof, a wave generator (5) that causes the first 10and second external teeth (45, 46) to partially mesh with the first and second internally toothed gears(2, 3), a clutch mechanism (6) that can selectively switch the first and second internally toothed gears (2, 3) into a fixed state. Input rotation from the wave generator (5) can be reduced in speed at a different speed ratio and derived from the 15externally toothed gear (4) by selectively switching the first and second internally toothed gears (2, 3) into a fixed state.