Split Power Infinitely Variable Transmission Architecture
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Solution Overview
Problem
Current infinitely variable transmission architectures subject the variator to the entire power load recirculated through the transmission, leading to inefficient power handling and potential stress on the variator components.
Innovation Solution
The transmission design incorporates a plurality of clutches and gearsets that split and recirculate power in multiple paths, allowing the variator to operate with reduced power load by bypassing it in certain modes, thereby distributing the power load across different mechanical paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If power is recirculated through the variator in current infinitely variable transmission architectures, then continuous variable transmission ratios can be achieved, but the variator is subjected to the entire power load which leads to inefficient power handling and potential stress on the variator components
Solution Approach 1:
The power flow is segmented into multiple paths: a first power path through the variator for continuous ratio variation, and a second power path through the planetary gear train for fixed ratio transmission. This segmentation allows the variator to handle only the portion of power needed for ratio variation rather than the entire power load, reducing stress on variator components while maintaining continuous variable transmission capability.
Solution Approach 2:
The planetary gear train acts as an intermediary component that provides an alternative power path. By introducing this intermediary fixed-ratio transmission path, the system can bypass the variator when fixed ratios are sufficient, thereby reducing the power load on the variator and improving its reliability.
2Power
If the variator handles the entire recirculated power load, then all power transmission can be achieved through the variator, but power handling efficiency decreases and component lifespan is reduced
Solution Approach 1:
The power transmission function is segmented between two parallel paths: the variator path for continuous ratio adjustment and the planetary gear train path for fixed ratio transmission. This segmentation distributes the power load, allowing the variator to operate at reduced stress levels which extends component lifespan while maintaining full power transmission capability through the combined paths.
Solution Approach 2:
The system changes the operational parameters of the variator by reducing its power load through the split-power architecture. By operating the variator at lower power levels while utilizing the planetary gear train for portion of the power transmission, the component lifespan is extended without compromising the overall power transmission capability of the transmission system.
3Reliability
If multiple clutches and gearsets are added to split power paths, then power load on the variator is reduced, but device complexity increases
Solution Approach 1:
The planetary gear train serves multiple functions: it provides fixed ratio transmission paths, acts as a power splitting mechanism, and offers bypass routes for the variator. By making this single subsystem multi-functional, the patent reduces the need for additional separate components while achieving the goal of reducing variator power load and improving power handling efficiency.
Data Source
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AI summary
A transmission includes an input shaft, an output shaft, at least five planetary gearsets, a variable-ratio unit, and at least five clutches. The at least five clutches are selectively engageable in combination with one another to select one of a plurality of operating modes including at least one reverse mode, at least five forward modes, and at least five transition modes. One of the at least five transition modes is configured to transition the transmission from the at least one reverse mode to one of the at least five forward modes. Another one of the at least five transition modes is configured to transition the transmission from the one of the at least five forward modes to another of the at least five forward modes. Each of the at least five transition modes includes a fixed speed ratio defined between the input shaft and the output shaft.