Planetary Transmission Coupler Layout for Ten Forward Speeds
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Solution Overview
Problem
Current multi-speed transmissions face challenges in achieving a sufficient number of forward and reverse speed ratios using planetary gearsets and selective couplers, often requiring complex configurations that are difficult to manage effectively.
Innovation Solution
A multi-speed transmission system incorporating four planetary gearsets and seven selective couplers, including clutches and brakes, to achieve at least ten forward speed ratios and one reverse speed ratio, with specific couplings and interconnections allowing for efficient gear ratio changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and selective couplers are used to achieve more 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 component 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 system employs selective couplers (clutches and brakes) that can dynamically engage and disengage to change the operational configuration of planetary gearsets. This dynamic control allows the transmission to shift between different speed ratios and operational modes without mechanical reconfiguration, managing complexity through active control rather than static design.
2Adaptability or versatility
If multiple selective couplers are used to achieve wide gear ratio range, then the adaptability is improved, but the ease of operation deteriorates
Solution Approach 1:
The selective couplers serve multiple functions within the transmission system. Each coupler can engage different planetary gearsets and control various speed ratios, allowing a single coupler mechanism to perform multiple operational roles. This multi-functionality reduces the need for separate control mechanisms for each gear ratio change.
Solution Approach 2:
The selective couplers act as intermediary elements between the input and output members, mediating the torque transmission path through different planetary gearsets. By controlling which couplers are engaged, the system can smoothly transition between different speed ratios without direct mechanical reconfiguration, simplifying operation.
Data Source
AI summary
A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least ten forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, and a fourth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have four planetary gearsets and seven selective couplers. The seven selective couplers may include three clutches and four brakes.