Multi-speed planetary transmission with four gearsets
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Solution Overview
Problem
Current multi-speed transmissions face challenges in achieving a sufficient number of forward and reverse speed ratios efficiently using planetary gearsets and selective couplers, often requiring complex configurations and limited flexibility in gear ratio adjustments.
Innovation Solution
A multi-speed transmission system incorporating four planetary gearsets and six selective couplers, including clutches and brakes, which are actively or passively controlled to achieve at least nine forward and one reverse speed ratio through strategic engagement of these components, allowing for flexible torque transmission and gear ratio variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple planetary gearsets and selective couplers are used to achieve multiple forward and reverse speed ratios, then the number of speed ratios increases, but the device complexity increases
Solution Approach 1:
The transmission system is divided into multiple independent planetary gearsets (first, second, third planetary gearsets) each with its own sun gear, planet gears, and ring gear. These segmented gearsets can be independently controlled through selective couplers to achieve different speed ratios, allowing the system to provide multiple forward and reverse ratios without requiring a single overly complex gear mechanism.
Solution Approach 2:
The selective couplers serve multiple functions: they can couple different planetary gearsets to the input member, couple different gearsets to the output member, and enable both forward and reverse motion control. This multi-functionality allows a single component type to manage complex gear ratio selection across multiple planetary gearsets, reducing overall system complexity.
2Adaptability or versatility
If selective couplers are used to achieve flexible gear ratio adjustments, then adaptability improves, but device complexity increases
Solution Approach 1:
Each selective coupler is designed to perform multiple coupling functions: connecting different planetary gearsets to the input member, connecting different gearsets to the output member, and enabling both forward and reverse motion. This multi-functionality allows a single coupler component to manage complex gear ratio selection, reducing the need for additional specialized components and simplifying the overall control system.
Solution Approach 2:
The selective couplers are positioned and configured in advance to establish predetermined coupling paths between the planetary gearsets, input member, and output member. This preliminary arrangement allows for quick gear ratio adjustments without requiring complex real-time calculations or adjustments, as the coupling relationships are pre-established through the mechanical configuration of the couplers.
Data Source
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AI summary
A multi-speed transmission including a plurality planetary gearsets (108, 110, 112, 114) and a plurality of selective couplers (162, 164, 166, 168, 170, 172) is disclosed. The plurality of planetary gearsets comprises four planetary gearsets (108, 110, 112, 114), and the plurality of selective couplers (162, 164, 166, 168, 170, 172) includes three clutches (168, 170, 172) and three brakes (162, 164, 166).