Multi-Speed Planetary Transmission with Six-Coupler Gear Selection
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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, as they often require complex configurations of planetary gearsets and selective couplers, which can be cumbersome and less effective in providing the desired range of gear ratios.
Innovation Solution
A multi-speed transmission design incorporating four planetary gearsets and six selective couplers, including clutches and brakes, allows for the engagement of various combinations to achieve at least nine forward and one reverse speed ratio, utilizing a truth table to illustrate the selective engagement of couplers for optimal gear ratio manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plurality of planetary gearsets and selective couplers are used to achieve multiple forward and reverse speed ratios, then the number of speed ratios is improved, but the device complexity increases
Solution Approach 1:
The transmission system is divided into multiple planetary gearsets (first, second, third, and fourth planetary gearsets) with distinct configurations. Each gearset can be independently controlled through selective couplers, allowing the system to achieve multiple speed ratios by engaging different segments of the overall transmission system.
Solution Approach 2:
The transmission system employs selective couplers that can dynamically engage and disengage different planetary gearsets based on the desired speed ratio. This dynamic reconfiguration allows the system to adapt between different operational modes (forward gears, reverse, neutral) without requiring a completely static complex mechanism.
2Adaptability or versatility
If selective couplers are strategically engaged to provide wide range of speed ratios, then the adaptability is improved, but the ease of operation deteriorates
Solution Approach 1:
The selective couplers serve multiple functions: they can engage different planetary gearsets, control torque flow paths, and achieve various speed ratios. Each coupler is designed to perform multiple operational roles, reducing the overall number of control elements needed and simplifying the operation interface.
Solution Approach 2:
The selective couplers act as intermediary elements between the input shaft and output shaft, mediating the torque transmission through different planetary gearsets. This intermediary mechanism allows complex gear ratio changes to be achieved through simple engagement/disengagement actions rather than direct complex control.
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 (166, 168, 170, 172) and a number of brakes (162, 164). 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 four clutches (166, 168, 170, 172) and two brakes (162, 164).