Planetary Transmission Coupler Layout for Nine Forward Ratios
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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, as they often require complex configurations and may not provide the desired range of gear ratios effectively.
Innovation Solution
A multi-speed transmission system incorporating multiple planetary gearsets and selective couplers, including clutches and brakes, is designed to achieve at least nine forward speed ratios and one reverse speed ratio by strategically engaging various combinations of selective couplers to interconnect gearset components, allowing for flexible torque transmission and gear ratio adjustments.
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 gear ratio range and adaptability are improved, but the device complexity increases
Solution Approach 1:
The transmission system is divided into multiple independent planetary gearsets (first, second, third, and fourth planetary gearsets), each capable of providing gear ratio changes. This segmentation allows the system to achieve a wide range of speed ratios by selectively engaging different gearsets, while maintaining modular architecture that manages complexity through standardized sub-units.
Solution Approach 2:
The selective couplers are designed with multi-functionality, serving as universal connecting elements that can engage various components across different planetary gearsets. Each coupler can connect multiple components simultaneously, enabling a single coupler to perform multiple functions in different operational modes, thereby reducing the total number of specialized components needed.
2Adaptability or versatility
If selective couplers are strategically engaged to interconnect gearset components, then the flexibility in torque transmission and gear ratio adjustment is improved, but the control system complexity increases
Solution Approach 1:
The transmission system employs dynamic engagement and disengagement of selective couplers to achieve different torque transmission paths and gear ratios. The couplers can be selectively activated based on operational requirements, allowing the system to dynamically reconfigure its internal connections without mechanical reassembly, thereby providing flexibility while maintaining a relatively simple base structure.
Solution Approach 2:
The selective couplers act as intermediary elements between the planetary gearsets and the input/output members. These intermediaries facilitate controlled torque transmission by selectively connecting or disconnecting gearset components, enabling flexible gear ratio adjustment without requiring direct complex interactions between all system components.
3Productivity
If four planetary gearsets with multiple selective couplers are used, then the number of achievable speed ratios is improved, but the manufacturing complexity increases
Solution Approach 1:
The transmission is constructed from four distinct planetary gearset modules, each with standardized components (sun gears, planet gears, ring gears, and carriers). This segmentation enables independent manufacturing and testing of each module before final assembly, reducing overall manufacturing complexity while achieving a high number of speed ratios through modular combination.
Solution Approach 2:
Multiple planetary gearsets and selective couplers are merged into a compact integrated transmission assembly. The design combines these elements in a space-efficient manner where components share common mounting structures and alignment features, simplifying the manufacturing process while maximizing the number of achievable speed ratios within a constrained package size.
Data Source
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AI summary
A multi-speed transmission (100, 300) including a plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314) and a plurality of selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372) to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314) may include a first planetary gearset (108, 308), a second planetary gearset (110, 310), a third planetary gearset (112, 312), and a fourth planetary gearset (114, 314). The plurality of selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372) may include a number of clutches (166, 168, 170, 172, 366, 368, 370, 372) and a number of brakes (162, 164, 362, 364). The multi-speed transmission (100, 300) may have four planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314) and six selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372). The six selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372) may include four clutches (166, 168, 170, 172, 366, 368, 370, 372) and two brakes (162, 164, 362, 364).