Planetary Transmission Coupling Scheme for Nine Forward and Reverse 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 using existing planetary gearsets and selective couplers, which restrict their versatility and efficiency in power transmission applications.
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, allowing for flexible torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing planetary gearsets and selective couplers are used in multi-speed transmissions, then the transmission can achieve multiple speed ratios, but the number of forward and reverse speed ratios is insufficient
Solution Approach 1:
The transmission system is divided into multiple independent planetary gearsets (first, second, third planetary gearsets) that can be selectively engaged through individual clutches and brakes. Each planetary gearset can operate independently or in combination with others, allowing the system to achieve multiple speed ratios by engaging different combinations of gearsets rather than using a single complex gearset
Solution Approach 2:
The planetary gearsets are configured with shared components (e.g., the ring gear of the first planetary gearset serves as the sun gear of the second planetary gearset) allowing the same physical components to serve multiple functions. This multi-functionality enables the system to achieve both forward and reverse speed ratios using the same gearset structure, increasing versatility without proportionally increasing complexity
2Productivity
If multiple planetary gearsets and selective couplers are added to increase the number of speed ratios, then the versatility and efficiency of power transmission improve, but the device complexity increases
Solution Approach 1:
Multiple planetary gearsets are merged into a single integrated transmission system with shared components and common input/output members. The clutches and brakes are integrated into a unified control system that can selectively engage different gearset combinations. This merging allows the system to achieve multiple speed ratios through coordinated operation of integrated components rather than through separate, independent mechanisms
Solution Approach 2:
The transmission system employs dynamic engagement and disengagement of clutches and brakes to selectively activate different planetary gearsets based on the desired speed ratio. This dynamic configuration allows the system to adapt its internal structure in real-time, achieving multiple forward and reverse speed ratios by changing which components are connected, rather than requiring all components to be permanently connected in a fixed complex arrangement
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 eighth selective couplers may include three clutches and five brakes.