Planetary Gearset Coupling Layout for Nine-Speed Transmissions
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Solution Overview
Problem
Current multi-speed transmissions face challenges in achieving a sufficient number of forward and reverse speed ratios efficiently, often requiring complex configurations of planetary gearsets and selective couplers to meet the demands of various applications.
Innovation Solution
A multi-speed transmission system incorporating multiple planetary gearsets and selective couplers, including clutches and brakes, is designed to provide at least nine forward speed ratios and one reverse speed ratio by strategically engaging various combinations of these components to optimize torque transfer and gear ratios.
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 increases, but the device complexity increases
Solution Approach 1:
The patent combines multiple planetary gearsets (first, second, third planetary gearsets) with selective couplers (clutches and brakes) into an integrated transmission system. The sun gear of the first planetary gearset is connected to the carrier of the second planetary gearset, and the ring gear of the second planetary gearset is connected to the sun gear of the third planetary gearset, creating a merged structure that achieves multiple speed ratios through coordinated engagement of different components rather than requiring separate, complex gear trains for each ratio.
Solution Approach 2:
The selective couplers (clutches and brakes) serve multiple functions within the transmission system. Each coupler can engage different components (sun gears, ring gears, carriers) to establish various gear ratios, and the same coupler may be involved in multiple ratio configurations. This multi-functionality allows a relatively small number of couplers to control a large number of forward and reverse speed ratios, reducing overall device complexity.
2Adaptability or versatility
If additional selective couplers and interconnectors are added to achieve more speed ratios, then the versatility of the transmission increases, but the manufacturing complexity increases
Solution Approach 1:
The transmission system is segmented into distinct functional modules: three planetary gearsets, multiple selective couplers (clutches and brakes), and interconnectors. Each planetary gearset can be manufactured as a separate assembly with its own sun gear, ring gear, and carrier. The selective couplers are positioned at specific locations to engage specific components, allowing for modular manufacturing and assembly. This segmentation reduces manufacturing complexity by breaking down the complex transmission into manageable, standardized components.
Solution Approach 2:
The patent specifies predetermined engagement configurations for the selective couplers to achieve different speed ratios. The clutches and brakes are pre-positioned to engage with specific components (sun gears, ring gears, carriers) of the planetary gearsets. This preliminary arrangement of couplers and interconnectors allows the transmission to achieve a wide range of speed ratios through simple engagement/disengagement actions rather than requiring complex real-time adjustments or additional manufacturing complexity.
Data Source
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AI summary
A multi-speed transmission (300) including a plurality of planetary gearsets (308, 310, 312, 314) and a plurality of selective couplers (362, 364, 366, 368, 370, 372) to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets includes a first planetary gearset (308), a second planetary gearset (310), a third planetary gearset (312), and a fourth planetary gearset (314). The plurality of selective couplers includes six selective couplers (362, 364, 366, 368, 370, 372) which may include three clutches (368, 370, 372) and three brakes (362, 364, 366).