Dual-Clutch Farm Transmission With Segmented Range Clutch Brakes
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Solution Overview
Problem
Existing dual-clutch transmission architectures for agricultural vehicles suffer from high energy losses due to large wet clutches, significant inertia during gear shifting, and increased fuel consumption, while also being cumbersome and costly to manufacture.
Innovation Solution
A dual-clutch transmission architecture with axially offset and staggered clutches, combined with a gear ratio stage and range gear stage, utilizing a unique gearing arrangement and additional speed ratios to reduce energy losses and enhance shifting efficiency, along with a compact design and cost-effective manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If large wet clutches are used to enable range gear shifting, then gear shifting capability is improved, but energy loss increases
Solution Approach 1:
The transmission is divided into a main clutch assembly and a range clutch assembly, with the range clutch further segmented into multiple independent clutch brakes (first through fourth clutch brakes). This segmentation allows selective engagement of smaller clutch brakes for range shifting instead of using a single large wet clutch, reducing energy loss while maintaining shifting capability.
Solution Approach 2:
The patent introduces an axial offset arrangement where the range clutch assembly is positioned axially offset from the main clutch assembly. This dimensional change allows the range clutch to operate independently with smaller clutch brakes, enabling range gear shifting without requiring a large wet clutch, thus reducing energy loss.
2Ease of operation
If traditional DCT architecture is used, then powershift capability is provided, but fuel consumption increases during shifting
Solution Approach 1:
The transmission system is segmented into a main clutch assembly for gear shifting and a separate range clutch assembly for range gear shifting. This segmentation allows powershift capability to be maintained through the main clutch while range shifts use smaller clutch brakes, reducing the inertia and resistant torque during shifting, thereby lowering fuel consumption.
Solution Approach 2:
The range clutch assembly acts as an intermediary mechanism between the engine and the main clutch assembly. By introducing this intermediate stage with smaller clutch brakes, the system can perform range gear shifting with reduced inertia and resistant torque, decreasing fuel consumption during shifting operations.
3Ease of operation
If more clutches are added to provide comprehensive gear shifting, then shifting capability is improved, but device complexity increases
Solution Approach 1:
The main clutch assembly and range clutch assembly are merged into a single transmission system with coordinated control. The range clutch assembly incorporates multiple clutch brakes (first through fourth) that work together with the main clutch, providing comprehensive gear shifting capability while sharing common structural elements and control mechanisms, thus managing device complexity.
Solution Approach 2:
The range clutch assembly serves multiple functions: it provides range gear shifting, assists in normal gear shifting, and can operate independently or in combination with the main clutch. This multi-functionality allows the system to achieve comprehensive shifting capability without proportionally increasing device complexity, as the same assembly performs multiple roles.
Data Source
Figure 1
Figure 1A
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AI summary
Architecture for a dual clutch transmission (1) for an off road vehicle provided with an input stage (A), a gear ratio stage (B) and a range gear ratio stage (C) operatively connected in series one to the other with respect to an input shaft (2) and an output shaft (3), the transmission (1) comprises selection elements (17) configured to selectively couple gears (14, 15) of gear ratio stage (B) to respective first and second shafts (11, 12) and a gearing module (30) defining intermediate speed ratios with respect to the speed ratios of the rage gear ratio stage (C).