Split-Power Ball Variator Transmission With Low Launch Loading
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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 variator and a planetary gear train with multiple power paths, including a variator bypass clutch that reduces the power load on the variator by redirecting power through alternative paths, allowing for continuous variation of transmission ratios and achieving zero output speed in geared neutral modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a ball variator is used in a single power flow transmission architecture, then the transmission can achieve infinite variability, but the variator experiences high loading at vehicle launch which reduces reliability
Solution Approach 1:
The transmission system is divided into two separate power flow paths: a first power flow path containing a first variator and a second power flow path containing a second variator. This segmentation allows each variator to handle a portion of the total power, reducing the loading on individual variators and improving reliability while maintaining infinite variability capability.
Solution Approach 2:
Two power flow paths are merged into a single transmission output, combining the capabilities of multiple variators to work together. This merging allows the system to achieve infinite variability through coordinated operation of both variators while distributing the mechanical loading across multiple components, thereby improving reliability.
2Device complexity
If a single power flow transmission architecture is used, then the device complexity is reduced, but the variator loading increases which harms reliability
Solution Approach 1:
The transmission is segmented into multiple power flow paths with separate variators, distributing the mechanical load across multiple components. This segmentation reduces the loading on each individual variator, improving reliability while the modular nature of the segmentation keeps the overall device complexity manageable.
3Use of energy by moving object
If variable ratio drive is used to improve fuel economy, then energy efficiency improves, but transmission losses increase which reduces overall efficiency
Solution Approach 1:
The patent replaces traditional mechanical transmission elements (gears, belts, chains) with a ball variator system that uses rolling ball elements to transmit power. This substitution reduces friction-based transmission losses while maintaining the ability to provide variable ratio drive for improved fuel economy, as the rolling contact mechanism is more efficient than sliding or meshing mechanical contacts.
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 design reduces the power load on the variator, enhancing its operational efficiency and reliability by distributing the power load across multiple paths, thereby improving the transmission's ability to handle recirculated power and maintain performance across various operating modes.
Implementation Method 1
a first planetary type ball variator having a first set of planetary gears and a first set of sun gears
Implementation Method 2
planetary type ball variator with low variator loading
Data Source
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AI summary
A transmission includes an input shaft, an output shaft, at least four planetary gearsets, a variable-ratio unit, and at least four clutches. The input shaft is configured to receive torque from a drive unit. The output shaft is configured to transmit torque to a load. The at least four planetary gearsets, the variable-ratio unit, and the at least four clutches are arranged between the input shaft and the output shaft. The at least four clutches are selectively engageable in combination with one another to select one of at least four operating modes.