Multi-Speed Planetary Transmission With Six Couplers for Nine 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, as they often require complex configurations of planetary gearsets and selective couplers, which can lead to increased complexity and cost.
Innovation Solution
A multi-speed transmission design incorporating multiple planetary gearsets and selective couplers, including clutches and brakes, to achieve at least nine forward speed ratios and one reverse speed ratio, utilizing a combination of fixed and selective couplings to vary the gear ratios through various interconnections and coupler engagements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and selective couplers are used to achieve multiple 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 multiple selective couplers (first through sixth couplers) into an integrated transmission system. The couplers are strategically positioned to connect different components (sun gears, planet carriers, ring gears) across gearsets, enabling a single unified structure to achieve multiple speed ratios without requiring separate transmission systems for each ratio.
Solution Approach 2:
The selective couplers serve multiple functions: they can connect different planetary gearsets together, connect gearset components to the case, and enable various gear ratio configurations. The same coupler mechanism is used repeatedly throughout the transmission system to achieve different speed ratios, reducing the need for specialized components for each function.
2Adaptability or versatility
If complex configurations of planetary gearsets and selective couplers are used to achieve sufficient speed ratios, then the number of speed ratios increases, but the manufacturing cost increases
Solution Approach 1:
The transmission system is divided into discrete modular components: three planetary gearsets, six selective couplers, and a case. Each planetary gearset contains sun gears, planet gears, planet carriers, and ring gears as separate manufacturable units. This segmentation allows for standardized manufacturing processes, assembly line production, and potential modular assembly, reducing overall manufacturing complexity and cost.
Solution Approach 2:
The patent achieves different speed ratios by changing the engagement state of selective couplers rather than manufacturing different physical gear configurations. The same hardware structure can produce multiple speed ratios through parameter changes (coupler engagement/disengagement), eliminating the need for multiple sets of gears and reducing manufacturing requirements.
3Adaptability or versatility
If multiple selective couplers are used to achieve multiple speed ratios, then the gear ratio variation capability increases, but the device complexity increases
Solution Approach 1:
The transmission system employs dynamically controllable selective couplers that can be engaged or disengaged based on operating conditions. This dynamic control allows the system to adapt gear ratios in real-time without physical reconfiguration, maintaining a relatively simple static structure while achieving complex gear ratio variation through dynamic coupler operation.
Solution Approach 2:
The selective couplers act as intermediary elements between the planetary gearsets and the case, mediating the torque flow and speed ratio selection. Rather than directly connecting all gearset components, the couplers serve as controllable intermediaries that route power flow through different paths, simplifying the overall control architecture while maintaining gear ratio variation capability.
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).