Input Clutch Assembly Layout for Compact Infinitely Variable Transmissions
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Solution Overview
Problem
Conventional infinitely variable transmissions are too long to fit in on-highway applications like buses and suffer from mechanical damage and torsional vibrations due to the one-way clutch setup, which also affects engine performance during shutdown and startup.
Innovation Solution
A compact infinitely variable transmission design with a multi-axis gearing configuration, including an input shaft, output shaft, variator, and planetary gearsets, and an input coupler that reduces overall length and minimizes inertia return to the engine, using fewer clutch assemblies and positioning components on parallel but non-coaxial axes to enhance packaging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-way clutch is connected to ground to protect the variator assembly during engine shutdown, then the variator assembly is protected from mechanical damage, but the inertia is returned to the engine causing potential damage or performance impact
Solution Approach 1:
The patent extracts the harmful function of the one-way clutch by removing it from the system. Instead of using a one-way clutch connected to ground that returns inertia to the engine, the invention uses a different configuration where the variator assembly is directly coupled to the input shaft, and the clutch assembly is positioned to engage with the variator assembly without connecting to ground, thereby eliminating the harmful inertia return while maintaining protection functionality
Solution Approach 2:
The patent introduces an intermediary element - the clutch assembly positioned between the variator assembly and the input shaft - that mediates the protection function without creating the harmful one-way clutch configuration. This intermediary clutch assembly allows the system to protect the variator during shutdown without directly returning inertia to the engine by grounding the clutch
2Power
If conventional infinitely variable transmission gearing configuration is used, then the transmission can transfer power effectively, but the transmission becomes too long to fit within space near the rear end of a bus
Solution Approach 1:
The patent applies dimensional reconfiguration by arranging the input shaft, output shaft, and variator assembly along different axes rather than a single linear arrangement. The input shaft and output shaft are positioned on parallel but offset axes, and the variator assembly is positioned between them, creating a compact three-dimensional layout that reduces overall transmission length while maintaining effective power transmission pathways
Solution Approach 2:
The patent merges the clutch assembly with the variator assembly configuration, positioning the clutch to engage directly with the variator assembly rather than being a separate grounded component. This integration eliminates the need for additional space for a separate one-way clutch mechanism and its grounding structure, thereby reducing transmission length while maintaining protection functionality
3Reliability
If a one-way clutch is used to prevent reverse rotation during engine shutdown, then the variator assembly is protected from mechanical damage, but torsional vibrations affect the transmission during start-up
Solution Approach 1:
The patent extracts the harmful one-way clutch component from the system and replaces it with a different clutch assembly configuration that does not create torsional vibrations during start-up. The new configuration uses a clutch assembly that engages with the variator assembly in a manner that allows smooth start-up without the vibration-generating characteristics of a one-way clutch
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The present invention provides an infinitely variable transmission for a powered vehicle which includes a power source. The transmission includes an input shaft and an output shaft, the output shaft being spaced from the input shaft. The transmission further includes a variator coupled between the input shaft and output shaft. In addition, at least two planetary gearsets are disposed adjacent to the variator and an input coupler is configured to selectively couple the variator to the power source.