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 using existing configurations of planetary gearsets and selective couplers, which limits their versatility and efficiency in applications requiring varied torque transmission.
Innovation Solution
The proposed solution involves a multi-speed transmission system that combines multiple planetary gearsets with a specific arrangement of selective couplers, including clutches and brakes, to achieve at least nine forward speed ratios and one reverse speed ratio by selectively engaging various combinations of these components, allowing for flexible torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing configurations of planetary gearsets and selective couplers are used, then the transmission system structure is relatively simple, but the number of forward and reverse speed ratios is insufficient
Solution Approach 1:
The transmission system is divided into multiple planetary gearsets (first, second, third, and fourth planetary gearsets) with distinct configurations. Each gearset has its own sun gear, planet gears, ring gear, and carrier, allowing independent engagement through selective couplers to generate different speed ratios.
Solution Approach 2:
The planetary gearsets are arranged in a nested configuration where the fourth planetary gearset is positioned inside the third, the second is inside the third, and the first is inside the second. This nested arrangement allows multiple gearsets to occupy compact space while maintaining individual functionality through selective engagement.
2Adaptability or versatility
If multiple planetary gearsets with selective couplers are added to achieve more speed ratios, then the versatility increases, but the device complexity increases
Solution Approach 1:
The selective couplers serve multiple functions by selectively engaging different components (sun gears, ring gears, carriers) of different planetary gearsets. Each coupler can connect various elements to achieve different speed ratios, reverse ratios, and neutral positions, making the couplers multi-functional control elements.
Solution Approach 2:
The transmission system dynamically engages and disengages different planetary gearsets and their components through the selective couplers based on the required speed ratio. This dynamic engagement allows the system to adapt its configuration in real-time to provide the needed versatility without permanently fixing the complex structure.
Data Source
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AI summary
A multi-speed transmission (100, 300, 500, 700) including a plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314, 508, 512, 514, 708, 712) and a plurality of selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572, 762, 764, 766, 768, 770, 772) to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314, 508, 512, 514, 708, 712) may include a first planetary gearset (108, 308, 508, 708), a second planetary gearset (110, 310), a third planetary gearset (112, 312, 512, 712), 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, 762, 764, 766, 768, 770, 772) may include a number of clutches (164, 166, 364, 366, 564, 566, 764, 766) and a number ofbrakes (162, 168, 170, 172, 362, 368, 370, 372, 562, 568, 570, 572, 762, 768, 770, 772). The multi-speed transmission (100, 300, 500, 700) 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, 562, 564, 566, 568, 570, 572, 762, 764, 766, 768, 770, 772). The six selective couplers (162, 164, 166, 168, 170, 172, 362, 364, 366, 368, 370, 372, 562, 564, 566, 568, 570, 572, 762, 764, 766, 768, 770, 772) may include two clutches (164, 166, 364, 366, 564, 566, 764, 766) and four brakes (162, 168, 170, 172, 362, 368, 370, 372, 562, 568, 570, 572, 762, 768, 770, 772). The four planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314) may include three minus planetary gearsets (108, 112, 114) and one plus planetary gearset (110) or two minus planetary gearsets (308, 312) and two plus planetary gearsets (310, 314). The multi-speed transmission (100, 300, 500, 700) may include at least one Ravigneaux gearset (508, 708, 712).