Nested Dual Clutch Transaxle for Compact Vehicle Packaging
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Solution Overview
Problem
Current dual clutch transaxles face challenges in fitting within the limited space and location constraints of vehicles, particularly in recreational vehicles like utility task vehicles, where traditional layouts are not feasible.
Innovation Solution
A dual clutch transaxle design featuring a nested dual clutch assembly with an offset input shaft axis and counter shaft assembly, positioned below the input shaft assembly, and an electric shift motor, allowing for compact packaging without the need for gear reduction, enabling efficient torque transfer and rapid gear shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a standard vehicle layout with transmission in the middle of the vehicle is used, then the dual clutch transmission can be easily packaged with prop shafts running to front and rear bevel gear cases, but the transaxle cannot fit within the limited space between the passenger compartment and the rear differential in recreational vehicles
Solution Approach 1:
The patent applies nesting by placing the dual clutch assembly inside the transmission housing, with the clutch shafts and gears arranged in a nested configuration where the odd gear clutch shaft and even gear clutch shaft are positioned concentrically or in close proximity within the same housing space, effectively reducing the overall transaxle volume to fit recreational vehicle constraints
Solution Approach 2:
The patent repositions the output differential assembly from a traditional longitudinal arrangement to a position below the input shaft assembly, creating a vertical dimension utilization that reduces the transaxle's footprint in the horizontal space between the passenger compartment and rear differential, enabling fitting in recreational vehicles with limited longitudinal space
2Volume of moving object
If the output differential assembly is positioned below the input shaft assembly, then the transaxle achieves compact packaging for limited vehicle spaces, but the structural complexity increases
Solution Approach 1:
The patent merges the dual clutch assembly and transmission gear sets into a single integrated housing structure, where the clutch shafts, synchronizers, and gear trains share common mounting points and structural support, reducing the number of separate components and simplifying the overall assembly despite the unconventional vertical arrangement
3Speed
If rapid gear shifting is achieved through dual clutch operation, then shifting speed improves, but the device complexity increases due to nested clutch assembly
Solution Approach 1:
The patent implements preliminary action by pre-selecting the next gear through the synchronizer mechanism before the actual clutch engagement occurs, allowing the selected gear to be ready and synchronized before power transfer begins, enabling rapid shifts without complex sequential control systems
Solution Approach 2:
The patent uses synchronizer rings as intermediary components between the clutch shafts and the gear sets, which mediate the power transfer by gradually matching the speeds of engaging gears before full engagement, simplifying the control requirements for rapid shifting while maintaining smooth transitions
Data Source
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AI summary
A dual clutch transaxle is provided that includes a dual clutch assembly, an input shaft assembly, a counter shaft assembly, a shift assembly and at least one output assembly. The dual clutch assembly has a dual clutch axis and includes a first clutch shaft and a second clutch shaft. The input shaft assembly includes a nested first inner input shaft and a second outer input shaft that are operationally coupled to the first clutch shaft and a second clutch shaft. An input shaft axis is offset from the dual clutch axis of the dual clutch assembly. A plurality of drive gears of the input shaft assembly are operationally coupled to a plurality of driven gears of the counter shaft assembly. The shift assembly is operationally coupled to select. The at least one output assembly is operationally coupled to the counter shaft assembly.