Eccentric Wheel Transmission With Periodically Varied Speed Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pedal transmission systems using reciprocal treadle motion by human feet suffer from inefficient angle displacement ranges due to simple harmonic motion, leading to low transmission efficiency.
Innovation Solution
The introduction of an elliptical active driving wheel and an eccentric passive driven wheel, combined with a synchronous belt or chain, which allows for a periodically varying speed ratio through the use of an auxiliary wheel for pre-stressed tightening, enhancing the transmission efficiency by optimizing the mechanical angle displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional round active wheel and round passive wheel are used with a simple belt or chain transmission, then the structure is simple and easy to manufacture, but the transmission efficiency is low due to simple harmonic motion and inefficient angle displacement ranges
Solution Approach 1:
The patent applies asymmetry by using an elliptical active wheel instead of a conventional round wheel. The elliptical shape creates asymmetric radius variations during rotation, which transforms the simple harmonic motion into a more efficient motion pattern. This asymmetric geometry allows the transmission ratio to vary periodically, optimizing the angle displacement ranges and improving transmission efficiency while maintaining structural simplicity
Solution Approach 2:
The patent implements dynamics by introducing a variable transmission ratio through the elliptical wheel configuration. The transmission ratio dynamically changes during the rotation cycle, allowing the system to adapt to different operational phases. This dynamic characteristic enables the system to maximize efficiency during optimal treadling angles while maintaining ease of manufacture through the straightforward elliptical geometry
2Productivity
If an elliptical active wheel and eccentric passive wheel are used to achieve periodically varying speed ratio, then transmission efficiency is improved, but the device complexity increases
Solution Approach 1:
The elliptical active wheel and eccentric passive wheel create an asymmetric transmission system that achieves periodically varying speed ratio. This asymmetric configuration improves transmission efficiency by optimizing the angle displacement ranges, while the complexity remains manageable due to the straightforward geometric shapes and single auxiliary wheel addition
Solution Approach 2:
The auxiliary wheel serves as an intermediary element that facilitates the belt or chain transmission between the elliptical active wheel and eccentric passive wheel. This intermediary component enables the pre-stressed tightening function while adding minimal complexity to the overall system, as it integrates seamlessly with the existing transmission path
3Device complexity
If the belt or chain is used for transmission between wheels, then the structure is simple, but pre-stressed tightening is insufficient leading to slippage and energy loss
Solution Approach 1:
The auxiliary wheel acts as an intermediary that applies pre-stressed tightening to the belt or chain. By positioning the auxiliary wheel to press against the belt or chain, it creates sufficient friction force to prevent slippage during transmission. This solution maintains the simplicity of the belt/chain transmission structure while effectively reducing energy loss through the added tightening function
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 maximizes transmission speed ratios, enabling higher rotation speeds to be transmitted to the passive wheel during optimal treadling angles, thereby improving overall efficiency compared to conventional systems.
Implementation Method 1
an auxiliary wheel to perform pre-stressed tightening of the belt or chain
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
The present invention is structured by using one or both of an active wheel (113) and a passive wheel (413) being composed of an eccentric transmission wheel and being combined with a synchronous transmission belt (100) for forming an eccentric wheel transmission wheel series, so that in the reciprocal treadle performed by the human's feet, when the feet input forces at different angles from the treadle shafts (103,203) of the treadles (102,202) to an active wheel shaft (111) combined on the active wheel (113) through cranks (101,102), the active wheel (113) forms different transmission speed ratios relative to the passive wheel (413) according to the treadle angle.