Multi-Speed Planetary Transmission with Six Couplers for Nine Ratios
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Solution Overview
Problem
Current multi-speed transmissions face limitations in achieving a sufficient number of forward and reverse speed ratios using planetary gearsets and selective couplers, as they often require complex configurations and components that are difficult to manage effectively.
Innovation Solution
A multi-speed transmission system incorporating four planetary gearsets and six selective couplers, including clutches and brakes, is designed to achieve at least nine forward speed ratios and one reverse speed ratio by strategically engaging various combinations of these components to optimize gear interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and selective couplers are used to achieve more speed ratios, then the number of forward and reverse speed ratios is improved, but the device complexity increases
Solution Approach 1:
The transmission system is divided into four distinct planetary gearsets (first, second, third, and fourth), each with specific gearset components that can be independently controlled through selective couplers. This segmentation allows each gearset to contribute to different speed ratios, achieving nine forward and one reverse ratio without requiring a single overly complex gear arrangement.
Solution Approach 2:
The transmission employs six selective couplers that can be dynamically engaged or disengaged to change the operational configuration of the planetary gearsets. This dynamic control allows the system to achieve multiple speed ratios by selectively connecting different gearset components, providing versatility without permanently fixed complex mechanisms.
2Adaptability or versatility
If selective couplers are engaged to achieve various gear ratios, then the operational flexibility is improved, but the ease of operation deteriorates due to multiple components requiring coordination
Solution Approach 1:
Each selective coupler is designed to perform multiple functions by controlling different combinations of gearset components across the four planetary gearsets. For example, engaging specific couplers can achieve various forward speed ratios while other coupler combinations enable reverse ratios, allowing a single coupler system to manage diverse operational modes without requiring dedicated controls for each function.
3Device complexity
If fixed couplings are used to simplify the structure, then the device complexity is reduced, but the adaptability to achieve multiple speed ratios is limited
Solution Approach 1:
The transmission system merges four planetary gearsets into a single integrated structure where interconnectors link corresponding components across gearsets. This merging allows the system to maintain a relatively simple overall structure while achieving multiple speed ratios through the coordinated operation of the combined gearsets and selective couplers, rather than requiring entirely separate transmission systems for each ratio.
Data Source
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AI summary
A multi-speed transmission (100) including a plurality of planetary gearsets (108, 110, 112, 114) and a plurality of selective couplers (162, 164, 166, 168, 170, 172) to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets (108, 110, 112, 114) may include a first planetary gearset (108), a second planetary gearset (110), a third planetary gearset (112), and a fourth planetary gearset (114). The plurality of selective couplers (162, 164, 166, 168, 170, 172) may include a number of clutches and a number of brakes. The multi-speed transmission (100) may have four planetary gearsets (108, 110, 112, 114) and six selective couplers (162, 164, 166, 168, 170, 172). The six selective couplers (162, 164, 166, 168, 170, 172) may include three clutches and three brakes. The four planetary gearsets (108, 110, 112, 114) may include three minus planetary gearsets (108, 110, 112) and one plus planetary gearset (114).