Planetary Gearset Transmission Layout for Nine-Speed Ratio Versatility
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Solution Overview
Problem
Existing 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 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 couplers to alter the gearset interconnections, as illustrated in the provided diagrammatic view and truth table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing multi-speed transmissions use a plurality of planetary gearsets and selective couplers to achieve multiple speed ratios, then the number of forward and reverse speed ratios increases, but the device complexity and cost increase
Solution Approach 1:
The patent combines multiple planetary gearsets (first, second, third, and fourth planetary gearsets) with selective couplers into a unified transmission system where components are shared and interconnected. The selective couplers merge different gearset paths to achieve multiple speed ratios, reducing the need for separate gear trains for each ratio while maintaining versatility.
Solution Approach 2:
The selective couplers serve multiple functions by being able to connect different components (sun gears, planet carriers, ring gears) of different planetary gearsets in various configurations. Each coupler can engage with multiple components across different gearsets, allowing the same coupler to participate in forming different speed ratios through selective engagement, thereby reducing the total number of couplers needed.
2Adaptability or versatility
If existing multi-speed transmissions use complex configurations of planetary gearsets and selective couplers, then sufficient forward and reverse speed ratios are achieved, but production costs increase
Solution Approach 1:
The patent merges multiple planetary gearsets into a compact arrangement where components from different gearsets are interconnected through selective couplers. This consolidation reduces the total number of discrete components that need to be manufactured and assembled separately, thereby reducing production costs while achieving multiple speed ratios.
Solution Approach 2:
The selective couplers are designed with multi-functionality to engage with multiple components across different planetary gearsets. This universal design allows fewer couplers to perform the work of what would traditionally require more specialized components, simplifying the manufacturing process and reducing overall production costs.
3Adaptability or versatility
If existing multi-speed transmissions use additional elements and complex interconnections to achieve multiple speed ratios, then the speed ratio versatility improves, but the device complexity increases
Solution Approach 1:
The patent combines the functions of multiple planetary gearsets and selective couplers into an integrated system where the interconnections are shared across all gearsets. The selective couplers serve as common interconnection points that link different gearsets together, reducing the need for separate interconnection mechanisms for each speed ratio while maintaining versatility.
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 (168, 170, 172) and a number of brakes (162, 164, 166). 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 three clutches (168, 170, 172) and three brakes (162, 164, 166).