Automatic Transmission Power Train 12-Speed Design
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Solution Overview
Problem
Current automatic transmissions with fewer shift speeds face limitations in optimizing speed ratios, leading to suboptimal fuel mileage and performance, while manual transmissions with many speeds inconvenience drivers with excessive shifting.
Innovation Solution
A power train design incorporating four planetary gear sets, four clutches, and four brakes to achieve twelve forward speeds and three reverse speeds, allowing for more optimal speed ratio design and improved vehicle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of shift speeds is increased, then fuel mileage and performance are improved, but device complexity increases
Solution Approach 1:
The transmission is divided into two independent subsystems: a first subsystem with three planetary gear sets providing four forward speeds and one reverse speed, and a second subsystem with one planetary gear set providing three forward speeds. These subsystems are connected through clutches and brakes to achieve 12 forward speeds and 3 reverse speeds in total, allowing complex functionality to be achieved through modular segmentation
Solution Approach 2:
The patent combines multiple planetary gear sets (first, second, and third planetary gear sets in the first subsystem, and fourth planetary gear set in the second subsystem) with multiple clutches (first, second, third, and fourth clutches) and brakes (first, second, third, and fourth brakes) into an integrated power train system. The clutches selectively connect different planetary gear sets to the input shaft, while brakes selectively fix rotating members to the case, creating a merged system that achieves 12 forward speeds and 3 reverse speeds
2Productivity
If the number of shift speeds is increased, then speed ratio optimization is improved, but ease of operation deteriorates
Solution Approach 1:
The transmission control unit automatically executes shifting by controlling the operation of the power train components (clutches and brakes) without driver intervention. The system self-manages the complex 12-speed shifting operations, eliminating the need for manual shifting while achieving optimal speed ratios for fuel economy and performance
Data Source
AI summary
The present invention relates to a power train of an automatic transmission that outputs twelve forward speeds and three reverse speeds by operations of first and second input units, first and second output units, and a plurality of friction members that connect operating members of the first and second input units and the first and second output units to an input shaft, other operating members of the first and second input units, and the first and second output units, or a case.