Planetary Transmission Layout for Nine Forward and Reverse 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 existing planetary gearsets and selective couplers, limiting their versatility and efficiency.
Innovation Solution
The proposed solution involves a multi-speed transmission system comprising multiple planetary gearsets and selective couplers, including clutches and brakes, which are strategically engaged to achieve at least nine forward and nine reverse speed ratios by varying the interconnections between the gearsets and couplers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing planetary gearsets and selective couplers are used in conventional multi-speed transmissions, then the transmission can achieve some forward and reverse speed ratios, but the number of achievable speed ratios is insufficient, limiting versatility and efficiency
Solution Approach 1:
The transmission system is divided into multiple independent planetary gearsets (first, second, third, fourth, and fifth planetary gearsets) that can be selectively connected through individual selective couplers. This segmentation allows each gearset to contribute to different speed ratios, enabling the achievement of at least nine forward and nine reverse speed ratios without requiring a single complex gearset configuration
Solution Approach 2:
The selective couplers (clutches and brakes) enable dynamic reconfiguration of the planetary gearsets by selectively engaging and disengaging connections between different gearset components. This dynamic capability allows the transmission to achieve multiple speed ratios by varying which gearsets are active and how they are interconnected, providing versatility without permanent structural complexity
2Adaptability or versatility
If multiple planetary gearsets and selective couplers are added to achieve more speed ratios, then versatility improves, but the device complexity and number of components increases
Solution Approach 1:
Each selective coupler is designed to perform multiple functions by connecting different components across multiple planetary gearsets. The selective couplers can establish various interconnections between the first, second, third, fourth, and fifth planetary gearsets, allowing a single coupler to enable different speed ratio configurations depending on which gearset components it connects
Solution Approach 2:
The patent combines multiple planetary gearsets into a single integrated transmission system where the gearsets work together through the selective couplers. By merging the functionality of five planetary gearsets and eight selective couplers into one coordinated system, the transmission achieves at least nine forward and nine reverse speed ratios, providing a wide range of speed ratios while maintaining a unified device structure
Data Source
AI summary
A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least nine forward speed ratios and at least nine reverse speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, a fourth planetary gearset, and a fifth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have five planetary gearsets and eight selective couplers. The eight selective couplers may include three clutches and five brakes.