Multi-clutch Transmission Bypassing Torque Path
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Solution Overview
Problem
Current dual-clutch transmissions for heavy on- and off-road vehicles face challenges in providing high power transfer during gear shifts without power interruption, achieving high reduction ratios, being cost-effective, and fitting within limited vehicle space due to issues like power interruption, complex designs, and high component counts.
Innovation Solution
A modified dual-clutch transmission design incorporating a by-passing tooth clutch and a strengthened range section, which allows for seamless power transfer between low and high range gears without interruption, using existing gearwheels and minimizing additional components to maintain compactness and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a friction clutch is used to transfer power during gear shifts in a dual-clutch transmission with a range section, then power interruption can be avoided at all gear shifts, but the power transferred to the driven wheels is very small at shifts between low gears and the power dissipated in the friction clutch is large
Solution Approach 1:
A by-passing tooth clutch is introduced as an intermediary mechanism between the input shaft and range section. This tooth clutch engages to provide a direct mechanical connection that bypasses the friction clutch, enabling efficient power transfer during range section shifts without the energy losses associated with friction-based power transmission.
Solution Approach 2:
The power transfer path is segmented into two distinct pathways: a friction clutch pathway for normal operation and a by-passing tooth clutch pathway for range section shifts. This segmentation allows each pathway to be optimized for its specific function, with the tooth clutch handling high-torque range shifts efficiently.
2Reliability
If a dual-clutch transmission is designed with two separate countershafts to enable powershifting without power interruption, then gear shifts can be smooth, but the transmission becomes wider than a conventional stepped transmission which may lead to installation difficulties
Solution Approach 1:
The by-passing tooth clutch merges the functional capabilities of what would require separate countershafts into a single integrated mechanism. This consolidation maintains the powershifting capability while reducing the overall transmission width to match conventional stepped transmissions.
Solution Approach 2:
The by-passing tooth clutch serves multiple functions: it enables range section shifts, provides direct power transfer paths, and eliminates the need for additional countershafts. This multi-functionality reduces component count and transmission width while maintaining smooth shifting performance.
3Adaptability or versatility
If the number of gears and speed reduction ratios is increased to meet heavy duty vehicle requirements, then the transmission can provide more gear options, but the transmission becomes more complex and production costs increase
Solution Approach 1:
The range section is designed as a pre-configured module that can be selectively engaged to provide additional gear ratios. This preliminary preparation of alternative power paths allows the transmission to offer multiple gears without requiring a completely complex redesign, as the range section acts as a ready-to-engage extension of the main transmission.
Data Source
AI summary
A multi-clutch transmission for a motor vehicle with a prime mover has a main transmission, a range section and an output shaft, the main transmission including one input shaft, a main shaft and a main countershaft, the main shaft being rotationally fixed with a range input shaft of the range section, the range section including a range main shaft that is rotationally fixed with the output shaft, a range countershaft, range gearwheels that can selectively transfer power from the range input member to the range countershaft and on to the range main shaft, and range clutches, the multi-clutch transmission including a by-passing torque path in which power can be transferred when the range section is shifted, and where the by-passing torque path includes a by-passing clutch that selectively can rotationally lock the main countershaft to the range countershaft.