Planetary Transmission Layout for Nine-Speed Ratio Flexibility
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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 and limited flexibility in gear ratio adjustments.
Innovation Solution
The implementation of a multi-speed transmission system that combines four planetary gearsets with six selective couplers, including clutches and brakes, to achieve at least nine forward and one reverse speed ratio through specific interconnections and engagement configurations, allowing for flexible 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 speed ratios, then the number of forward and reverse speed ratios increases, 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 configurations. Each gearset handles specific speed ratio ranges, allowing the system to achieve multiple forward and reverse ratios without requiring a single overly complex gear arrangement. This segmentation enables modular complexity management.
Solution Approach 2:
The patent introduces multiple selective couplers (first through sixth selective couplers) that operate in parallel across different planetary gearsets. These couplers provide an additional dimensional layer of control, enabling independent engagement/disengagement of power paths through each gearset. This multi-dimensional coupling strategy achieves comprehensive speed ratio coverage while distributing complexity across multiple manageable components rather than concentrating it in a single complex mechanism.
2Adaptability or versatility
If selective couplers are added to achieve flexible gear ratio adjustments, then the adaptability of gear ratios improves, but the device complexity increases
Solution Approach 1:
The selective couplers are designed as dynamically controllable elements that can be engaged or disengaged based on operational requirements. Each coupler (first through sixth) provides dynamic switching capability between different power transmission paths through the planetary gearsets. This dynamic control enables flexible gear ratio adjustments without requiring permanent mechanical linkages for all possible ratios, thereby managing complexity through active control rather than passive mechanical complexity.
Solution Approach 2:
Each selective coupler serves multiple functions: it can engage different planetary gearsets, provide both forward and reverse ratio control, and operate in combination with other couplers to achieve various speed ratios. This multi-functionality reduces the need for dedicated components for each specific gear ratio, thereby achieving comprehensive adaptability while limiting the growth of device complexity through component versatility.
Data Source
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AI summary
A multi-speed transmission (100, 300, 500) including a plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314, 508, 510, 512, 514) and a plurality of selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572) to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset (108, 308, 508), a second planetary gearset (110, 310, 510), a third planetary gearset (112, 312, 512), and a fourth planetary gearset (114, 314, 514). The plurality of selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572) may include a number of clutches (166, 168, 170, 172, 366, 368, 370, 372, 566, 568, 570, 572) and a number of brakes (162, 164, 362, 364, 562, 564). The multi-speed transmission (100, 300, 500) may have four planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314, 508, 510, 512, 514) and six selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572). The six selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572) may include four clutches (166, 168, 170, 172, 366, 368, 370, 372, 566, 568, 570, 572) and two brakes (162, 164, 362, 364, 562, 564).