Multi-Speed Planetary Transmission Layout for Wide Ratio Range
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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 interconnections and multiple components, which can lead to increased complexity and cost.
Innovation Solution
The proposed solution involves a multi-speed transmission system utilizing four planetary gearsets and six selective couplers, including clutches and brakes, to achieve at least nine forward and one reverse speed ratio through specific interconnections and engagement configurations, as illustrated in various truth tables, allowing for efficient torque transfer 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 planetary gearsets (first, second, third, and fourth planetary gearsets) with distinct interconnection paths. Each gearset can be selectively engaged through dedicated selective couplers, allowing independent control of different gear ratio paths. This segmentation enables achieving multiple speed ratios (at least nine forward and one reverse) without requiring a fully interconnected complex system, as each segment serves specific gear ratio functions.
Solution Approach 2:
The selective couplers serve multiple functions: they selectively engage different planetary gearsets, control torque transfer paths, and enable both forward and reverse speed ratios through the same component type. The interconnectors also serve dual purposes by connecting different gearset components (sun gears, planet carriers, ring gears) across multiple gearsets, reducing the need for dedicated components for each function.
2Adaptability or versatility
If additional interconnectors and selective couplers are added to achieve more speed ratios, then the speed ratio range expands, but the manufacturing cost increases
Solution Approach 1:
Multiple planetary gearsets are merged into a single integrated transmission system with shared interconnectors. The interconnectors combine multiple functions by connecting different gearset components (sun gears, planet carriers, ring gears) across multiple gearsets simultaneously. This merging approach achieves an expanded speed ratio range (at least nine forward and one reverse) without proportionally increasing component count, as one interconnector can serve multiple engagement paths.
Solution Approach 2:
The selective couplers are designed as universal components that can engage different planetary gearsets and control various torque transfer paths using the same component type. This multi-functionality reduces manufacturing cost by standardizing components rather than requiring unique components for each speed ratio function.
3Adaptability or versatility
If complex interconnections are used to achieve multiple speed ratios, then the gear ratio variability increases, but the system reliability decreases
Solution Approach 1:
The transmission system is segmented into distinct planetary gearsets with dedicated selective couplers for each. This segmentation isolates potential failure points, as a malfunction in one gearset or selective coupler does not necessarily affect the operation of other gearsets. The modular segmented architecture maintains system reliability while achieving high gear ratio variability (at least nine forward and one reverse speed ratios).
Data Source
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AI summary
A multi-speed transmission (100, 250, 300, 450, 500, 650) including a plurality of planetary gearsets and a plurality of selective couplers (162, 164, 166, 168, 170, 254, 362, 364, 366, 368, 370, 372, 454, 562, 564, 566, 568, 570, 572, 654) to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset (108), a second planetary gearset (110), a third planetary gearset (112), and a fourth planetary gearset (114). The plurality of selective couplers (162, 164, 166, 168, 170, 254, 362, 364, 366, 368, 370, 372, 454, 562, 564, 566, 568, 570, 572, 654) may include a number of clutches and a number of brakes. The multi-speed transmission (100, 250, 300, 450, 500, 650) may have four planetary gearsets and six selective couplers (162, 164, 166, 168, 170, 254, 362, 364, 366, 368, 370, 372, 454, 562, 564, 566, 568, 570, 572, 654). The six selective couplers (162, 164, 166, 168, 170, 254, 362, 364, 366, 368, 370, 372, 454, 562, 564, 566, 568, 570, 572, 654) may include four clutches and two brakes or three clutches and three brakes.