Dual-Clutch Transmission Fluid Partitioning for Compact Lubrication
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Solution Overview
Problem
Dual-clutch transmissions (DCTs) have not been widely adopted in off-road vehicles due to high manufacturing costs and packaging issues, and maintaining efficient lubrication of components is challenging in limited space.
Innovation Solution
A dual-clutch transmission design with a transmission housing that includes an internal dividing wall to separate fluid flow, a transmission fluid distribution system with pumps and channels, and a heat exchanger to manage lubrication and cooling, allowing efficient packaging and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a dual-clutch transmission is packaged in limited engine compartment space, then the transmission size is reduced, but maintaining efficient lubrication of components becomes difficult
Solution Approach 1:
The transmission housing is divided into multiple chambers by internal dividing walls, with each chamber containing specific components (clutches, gears, shafts). This segmentation allows independent lubrication circuits for each chamber, ensuring adequate lubrication coverage even in a compact overall transmission size. The fluid distribution system includes separate fluid channels that route lubricant to each chamber independently.
Solution Approach 2:
A hydraulic fluid distribution system is implemented with pumps, fluid channels, and distribution points throughout the transmission housing. The system uses pressurized transmission fluid to deliver lubrication to all internal components including clutches, gears, and bearings. The hydraulic system ensures consistent lubrication delivery regardless of transmission orientation or compact packaging configuration.
2Volume of moving object
If the transmission housing is compact to reduce packaging space, then the overall size is reduced, but heat dissipation and cooling of components becomes challenging
Solution Approach 1:
The transmission housing incorporates internal dividing walls that create separate chambers, allowing dedicated cooling pathways and heat exchanger integration for each chamber. This segmentation enables efficient heat management in a compact design by preventing heat accumulation in specific high-load areas while maintaining overall compact dimensions.
Solution Approach 2:
The hydraulic fluid distribution system serves dual purposes: lubrication and cooling. The transmission fluid circulating through the hydraulic channels absorbs heat from components and transports it to external heat exchangers mounted on the transmission housing, enabling effective thermal management in the compact design.
3Ease of manufacture
If the transmission design is simplified to reduce manufacturing costs, then manufacturing complexity decreases, but adequate lubrication coverage of all components may be compromised
Solution Approach 1:
The transmission housing serves multiple functions: structural enclosure, fluid distribution conduit, heat exchanger mounting surface, and component mounting structure. The internal dividing walls serve both structural separation and fluid flow management functions. This multi-functionality reduces the need for additional separate components, lowering manufacturing complexity while ensuring adequate lubrication coverage.
Solution Approach 2:
The transmission fluid distribution system is integrated into the housing structure itself, with fluid channels formed as part of the housing walls and partitions. This self-integrated design eliminates the need for separate external piping and distribution components, reducing manufacturing steps and assembly complexity while maintaining comprehensive lubrication 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
The design enables effective lubrication and cooling of DCT components, facilitating efficient operation and reducing manufacturing costs, thus making DCTs suitable for off-road vehicles.
Implementation Method 1
a primary pump fluidly connected to the fluid tank and to the first and second chambers, the primary pump being configured to pump transmission fluid to the first and second chambers
Implementation Method 2
a heat exchanger fluidly connected to the primary pump and configured to absorb heat from transmission fluid received from the primary pump
Implementation Method 3
an air separator disposed in the separator compartment and configured to separate air from transmission fluid
Implementation Method 4
the internal dividing wall being configured to limit flow of transmission fluid between the first and second chambers
Data Source
AI summary
A transmission for a vehicle (20) includes: an input shaft (122) for connection to an internal combustion engine (52) of the vehicle (20); a gear (605) shaft (122, 199, 400A, 400B) selectively operatively connected to the input shaft (122); a clutch selectively actuatable to transmit motion between the input shaft (122) and the gear (605) shaft (122, 199, 400A, 400B) for selectively operating the transmission in one of a plurality of transmission gears (600); an output shaft (740) operatively connected to the gear (605) shaft (122, 199, 400A, 400B) at least in part by the transmission gears (600); and a transmission housing (102) at least partly enclosing the input shaft (122), the transmission gears (600), the clutch and the output shaft (740). An internal dividing wall (506, 510) defines first and second chambers (350A, 502), the internal dividing wall (506, 510) being configured to limit flow of transmission fluid between the first and second chambers (350A, 502). The input shaft (122) and the clutch are disposed within the first chamber (350A, 350B, 508). The transmission gears (600) and the output shaft (740) are disposed within the second chamber (350A, 350B, 508).