Multi-Clutch Transmission Shared Countershaft Design
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Solution Overview
Problem
Existing dual-clutch transmissions for heavy on- and off-road vehicles face challenges such as insufficient reverse gears, bulkiness, high production costs, and installation difficulties, while maintaining efficient power transfer and low power losses.
Innovation Solution
A multi-clutch transmission design featuring a single main shaft, countershaft, and reverse shaft with a shared gear wheel that transfers power in all reverse and at least two forward speed ratios, allowing for continuous power transfer and compactness, enabling the same number of reverse and forward gears with high tractive force and speed capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If dual clutch transmission is designed with two separate countershafts, then power transfer capability is improved, but transmission width increases making installation difficult
Solution Approach 1:
The patent merges the functions of two separate countershafts into a single shared countershaft that serves both sub-transmissions. This consolidation reduces the overall transmission width while maintaining the power transfer capability of dual clutch configuration, directly resolving the contradiction between power capability and installation space.
Solution Approach 2:
The single countershaft is designed to be universal, serving multiple functions: it supports gearwheels for both first and second sub-transmissions, and can work with either input shaft. This multi-functionality allows the transmission to maintain dual clutch power transfer capabilities while using a compact single-countershaft design.
2Length of moving object
If dual clutch transmission uses one countershaft with loose gearwheels, then transmission compactness is improved, but number of reverse gears is insufficient for heavy duty vehicles
Solution Approach 1:
The patent segments the transmission into two functional sub-transmissions (first and second sub-transmissions) that share a common countershaft. Each sub-transmission can provide reverse gears through its dedicated input shaft and clutch, enabling the compact design to deliver multiple reverse gear ratios suitable for heavy duty applications.
Solution Approach 2:
The patent adds a second input shaft and associated clutch mechanism along the same countershaft, effectively utilizing the longitudinal dimension rather than expanding radially. This allows multiple reverse gears to be achieved within the same compact footprint by stacking functional elements along the input shaft axis.
3Adaptability or versatility
If special power path for reverse gears is added, then number of reverse gears is improved, but device complexity and production cost increase
Solution Approach 1:
The patent combines the reverse gear functionality into the existing forward gear meshing structure. By using the same countershaft and gearwheels that already exist for forward motion, the design achieves multiple reverse gears without adding separate power paths or duplicate components, thereby avoiding increased complexity and production costs.
Data Source
AI summary
A multi-clutch transmission is provided with a first and a second input frictional clutch, an input arrangement for establishing a driving connection of a prime mover and the first and second frictional clutches, and a main transmission. The main transmission has a first and a second rotational axis about which a main shaft and a countershaft is arranged respectively, an output shaft and connection means for establishing a driving connection between the main shaft and the output shaft, and least two input shafts, which are connected to the first and second input frictional clutch, and a reverse shaft provided with a first reverse gear wheel. A reverse gear is achieved by transferring power over the reverse shaft to the output shaft.