Planetary Transmission Coupler Architecture for Nine Forward Ratios
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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 using planetary gearsets and selective couplers, as they often require complex interconnections and control systems to achieve the desired gear ratios.
Innovation Solution
The use of a multi-speed transmission system comprising multiple planetary gearsets and selective couplers, including clutches and brakes, which are actively or passively controlled to achieve at least nine forward speed ratios and one reverse speed ratio by selectively engaging various combinations of these components to alter the gear connections and provide the necessary torque transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and selective couplers are used to achieve multiple forward and reverse speed ratios, then the number of gear ratios is improved, but the device complexity increases
Solution Approach 1:
The transmission system is divided into multiple independent planetary gearsets (first, second, third, and fourth planetary gearsets) that can be selectively engaged through individual selective couplers. Each planetary gearset can operate independently or in combination with others, allowing the system to achieve multiple forward and reverse speed ratios by engaging different combinations of gearsets rather than requiring a single complex interconnected system
Solution Approach 2:
The selective couplers are configured to be selectively engaged and disengaged based on desired gear ratio requirements. This dynamic engagement allows the transmission system to adapt its configuration in real-time, switching between different planetary gearsets to achieve the needed number of forward and reverse speed ratios without maintaining permanent complex interconnections
2Adaptability or versatility
If complex interconnections are used to achieve desired gear ratios, then the adaptability is improved, but the ease of operation deteriorates
Solution Approach 1:
By segmenting the transmission into separate planetary gearsets with dedicated selective couplers, the control system can engage specific gearsets independently rather than managing complex interconnections across the entire system. This segmentation simplifies the control logic for achieving desired gear ratios
Solution Approach 2:
The selective couplers act as intermediaries between the input member and the various planetary gearsets. Each selective coupler simplifies the control interface by providing a direct engagement point to specific gearsets, reducing the complexity of the overall control system needed to achieve the desired adaptability
Data Source
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AI summary
A multi-speed transmission (100, 300) including a plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314) and a plurality of selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372) to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314) may include a first planetary gearset (108, 308), a second planetary gearset (110, 310), a third planetary gearset (112, 312), and a fourth planetary gearset (114, 314). The plurality of selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372) may include a number of clutches (168, 170, 172, 368, 370, 372) and a number of brakes (162, 164, 166, 362, 364, 366). The multi-speed transmission (100, 300) may have four planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314) and six selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372). The six selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372) may include three clutches (168, 170, 172, 368, 370, 372) and three brakes (162, 164, 166, 362, 364, 366).