Chain-Driven CVT Frustoconical Assembly for Low-Vibration Shifting
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Solution Overview
Problem
Conventional continuously variable transmissions face issues with maintaining optimal engine speed and efficiency due to fixed gear ratios, leading to increased power use, fuel consumption, and potential transmission damage. Friction-based designs suffer from uncertainty, wear, and power losses, and are often complex, heavy, and costly.
Innovation Solution
A continuously variable transmission design featuring frustoconical members with guide railing slots and unidirectional sprocket wheels, which maintain chain tension and shape, reducing vibration and wear, and allowing for smooth power delivery without relying on friction, while enabling efficient gear ratio changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If friction-based continuously variable transmissions are used, then power transmission is achieved, but power losses and wear occur due to slipping
Solution Approach 1:
The patent replaces the friction-based mechanical power transmission system with a positive engagement system using a chain and sprockets. The chain engages with the sprocket teeth to transmit power directly without relying on friction, eliminating power losses and wear associated with friction-based systems while ensuring reliable and certain power transmission.
2Productivity
If conventional fixed gear ratio transmissions are used, then structural simplicity is maintained, but engine speed cannot be optimized for power and efficiency
Solution Approach 1:
The patent employs dynamically adjustable sprocket positions that can be radially moved toward or away from the center of the driver and driven assemblies. This dynamic adjustment capability allows the transmission ratio to be continuously varied, enabling optimization of engine speed for maximum power and efficiency while maintaining a relatively simple chain-driven structure.
3Reliability
If friction-based variable transmissions are made more complex to improve reliability, then power transmission stability increases, but weight and cost increase
Solution Approach 1:
The patent substitutes the complex friction-based control mechanisms with a simpler positive engagement chain drive system. The chain and sprocket configuration provides inherent reliability through direct mechanical engagement without requiring complex friction control mechanisms, thereby achieving stable power transmission with reduced weight.
4Device complexity
If chain or belt is allowed to extend straight between sprocket teeth, then mechanical simplicity is maintained, but vibration increases
Solution Approach 1:
The patent introduces curved guide surfaces (circumferential valleys) that constrain the chain to follow a curved path between sprocket teeth rather than allowing it to extend straight. This curvature configuration reduces vibration by maintaining consistent chain tension and engagement geometry, while the guide surfaces are integrated into the existing assembly structure to minimize added complexity.
Data Source
AI summary
An improvement to continuously variable transmissions whereby power is transmitted from a driver axle to a driven axle through a variable transmission mechanism. A plurality of unidirectional sprocket wheels positioned radially around a driver axle within a set of frustoconical members is provided so that the distance from the driver axle can be adjusted. The unidirectional sprocket wheels are connected by a chain to a similar driven axle portion. This low vibration, high torque capable transmission is superior to variable transmissions that rely on friction-based power transmissions that can slip during operation.