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 efficiently, as they often require complex configurations of planetary gearsets and selective couplers, which can lead to increased complexity and reduced reliability.
Innovation Solution
A multi-speed transmission design incorporating four planetary gearsets and six selective couplers, including clutches and brakes, to achieve at least nine forward and one reverse speed ratio by strategically engaging various combinations of these components, as illustrated in the provided diagrammatic view and truth table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex configurations of planetary gearsets and selective couplers are used to achieve sufficient forward and reverse speed ratios, then the number of speed ratios is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple planetary gearsets (first, second, third planetary gearsets) into a unified transmission system where they share common components such as the stationary member, input member, and output member. This merging approach allows the system to achieve multiple speed ratios through coordinated engagement of selective couplers rather than requiring separate, complex configurations for each ratio.
Solution Approach 2:
The selective couplers are designed to perform multiple functions by selectively engaging different combinations of planetary gearset components. The same set of six selective couplers can achieve at least nine forward speed ratios and at least one reverse speed ratio by varying which components they connect, eliminating the need for dedicated mechanisms for each speed ratio.
2Adaptability or versatility
If complex configurations of planetary gearsets and selective couplers are used to achieve sufficient forward and reverse speed ratios, then the number of speed ratios is improved, but the reliability is reduced
Solution Approach 1:
By merging multiple planetary gearsets into a shared system with common input and output members, the patent reduces the total number of discrete components that could potentially fail. The selective couplers are engaged in specific combinations to achieve different speed ratios, and the system is designed so that not all couplers need to be engaged simultaneously, reducing the complexity of the engagement control and improving reliability.
3Device complexity
If fewer components are used to achieve multiple speed ratios, then the device complexity is reduced, but the ability to achieve sufficient forward and reverse speed ratios may be compromised
Solution Approach 1:
The patent employs six selective couplers that can be engaged in various combinations to achieve at least nine forward speed ratios and at least one reverse speed ratio. Each selective coupler is designed to connect specific components of the planetary gearsets, and by selectively engaging different subsets of these six couplers, the system achieves multiple speed ratios without requiring additional components for each ratio.
Solution Approach 2:
The system achieves dynamic adaptability through the selective engagement of couplers. The engagement state of each selective coupler can be changed independently to adapt the transmission system to different operating conditions and speed ratio requirements, allowing a fixed set of six components to provide versatile speed ratio selection.
Data Source
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AI summary
A multi-speed transmission (100) including a plurality of planetary gearsets 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 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 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.