Dual-Clutch Transmission Linking Gear for Faster Synchronization
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Solution Overview
Problem
Dual-clutch transmissions (DCTs) face challenges in synchronization, leading to over-engineering of synchronizers due to the need to accelerate significant masses, resulting in increased construction costs and fuel wastage, and replicating forward gears in reverse configurations in a compact layout is difficult.
Innovation Solution
Incorporating a linking gear that rotates part of the un-powered clutch mass, reducing the load on synchronizers and allowing them to be manufactured as lighter duty items, while also enabling a compact and efficient arrangement that allows for identical gear components with different ratios, eliminating the need for a reversing gear module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If synchronizers are designed to accelerate significant masses in conventional DCTs, then reliable gear shifting is achieved, but construction costs increase and fuel consumption rises
Solution Approach 1:
The transmission is divided into two separate branches (odd-numbered gears branch and even-numbered gears branch), each with its own clutch and synchronizer. This segmentation allows synchronizers to only accelerate smaller masses within their respective branches rather than the entire transmission mass, reducing synchronizer size and cost while maintaining reliable shifting.
Solution Approach 2:
The next gear is pre-selected in the un-powered branch before the current gear is disengaged. This preliminary action allows the synchronizer to engage the pre-selected gear without needing to accelerate the full transmission mass, as the gear is already positioned and ready for engagement, reducing the workload on synchronizers.
2Productivity
If synchronizers accelerate significant masses in conventional DCTs, then gear shifting is completed, but shifting time increases and fuel efficiency decreases
Solution Approach 1:
By segmenting the transmission into two branches with separate synchronizers, each synchronizer handles a smaller mass independently. This reduces the time required for each synchronizing operation, enabling faster overall gear shifting while completing the necessary gear changes.
Solution Approach 2:
The next gear is pre-positioned in the un-powered branch before shifting begins. This preliminary positioning eliminates the need to accelerate the entire transmission mass during shifting, reducing shifting time and improving fuel efficiency by minimizing the duration of torque interruption.
3Adaptability or versatility
If forward gears are replicated in reverse configurations, then complete gear coverage is achieved, but transmission layout complexity increases
Solution Approach 1:
The same set of gear components (gears, shafts, synchronizers) is used for both forward and reverse configurations by selectively engaging different branches. The odd-numbered gears branch and even-numbered gears branch serve multiple functions, eliminating the need for separate reverse gear components and simplifying the overall layout while maintaining complete gear coverage.
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 solution reduces shifting time, lowers manufacturing and maintenance costs, and improves fuel efficiency by minimizing the need to accelerate massive transmission parts, while enabling a compact design with reduced inventory requirements for spare parts.
Implementation Method 1
Incorporating a linking gear that rotates part of the un-powered clutch mass
Implementation Method 2
a pair of clutches only one of which transmits drive at any one time
Data Source
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AI summary
A dual-clutch transmission (10), for a vehicle, comprises an even gears clutch (13) and an associated even gears shaft (46) supporting at least two even-numbered rotary gears (22, 23, 24, 26), the even gears clutch (13) being for transmitting rotary input drive via a selected one of the even-numbered rotary gears (22, 23, 24, 26) to a transmission output component (32); an odd gears clutch (12) and an associated odd gears shaft (44) supporting at least two odd-numbered rotary gears (17, 18, 19, 21), the odd gears clutch (12) being for transmitting rotary input drive via a selected one of the odd-numbered rotary gears (17, 18, 19, 21) to the output component (32), the transmission output component (32) being selectively connectable to one respective said even- or odd- numbered gear at a time and the even and odd gears clutches (13, 12) being arranged to transmit drive on a mutually exclusive basis, wherein the even gears clutch (13) and the odd gears clutch (12) each include a rotatable output member (56, 57), the rotatable output members (56, 57) of the respective clutches (13, 12) being linked by at least one rotatable linking gear (58, 59) that is integral with the transmission (10).