Multi-Speed Planetary Transmission with Six Couplers 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 using a combination of 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 incorporates four planetary gearsets and six selective couplers, including clutches and brakes, to achieve at least nine forward speed ratios and one reverse speed ratio through specific interconnections and coupler engagements, as illustrated in various truth tables and diagrams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a sufficient number of forward and reverse speed ratios is achieved using planetary gearsets and selective couplers, then the transmission capability is improved, but the device complexity increases

Engineering Contradiction:
Improvetransmission capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple planetary gearsets (first, second, third planetary gearsets) with selective couplers (first, second, third, fourth couplers) into an integrated transmission system. The sun gears of different planetary gearsets are connected through shared carriers and couplers, merging multiple gear trains into a unified structure that achieves multiple speed ratios without requiring separate transmission systems for each ratio.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The selective couplers serve multiple functions: they connect different planetary gearsets, enable various speed ratio configurations, and provide both forward and reverse transmission capabilities. The first coupler connects sun gears and enables different gear configurations, while the second coupler connects carriers and facilitates multi-ratio transmission, making each coupler a multi-functional element that contributes to overall transmission versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If complex configurations of planetary gearsets and selective couplers are used to achieve multiple speed ratios, then the gear ratio range is improved, but the ease of manufacture deteriorates

Engineering Contradiction:
Improvegear ratio rangeVSAvoidease of manufacture
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The transmission system is divided into distinct modular segments: first planetary gearset with its coupler, second planetary gearset with its coupler, and third planetary gearset with its coupler. Each planetary gearset can be manufactured and assembled as a separate module, then integrated into the complete transmission system. This segmentation allows for standardized manufacturing of individual gearsets while achieving complex overall functionality through their combination.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If multiple selective couplers are used to achieve flexible gear ratio adjustments, then the adaptability is improved, but the device complexity increases

Engineering Contradiction:
Improvegear ratio adjustmentsVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The selective couplers act as intermediary elements that mediate between the input shaft and output shaft through different planetary gearsets. Each coupler provides a selective connection point that enables different power transmission paths. The first coupler mediates connections between sun gears, the second coupler mediates connections between carriers, and the third and fourth couplers provide additional selective connection options, creating a controlled complexity that enables flexible gear ratio adjustment without requiring a completely complex system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3312459B1Multi-speed planetary transmission
Publication Date: 2021.08.11 ALLISON TRANSMISSION INC
  • EP3312459B1 patent drawingFigure 1
  • EP3312459B1 patent drawingFigure 2
  • EP3312459B1 patent drawingFigure 3

AI summary

A multi-speed transmission (100, 300, 500, 700, 900, 1100) including a plurality of planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314, 508, 510, 512, 514, 708, 710, 712, 714, 908, 910, 912, 914, 1108, 1110, 1112, 1114) 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, 962, 964, 966, 968, 970, 972, 1162, 1164, 1166, 1168, 1170, 1172) to achieve at least nine forward speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset (108, 308, 508, 708, 908, 1108), a second planetary gearset (110, 310, 510, 710, 910, 1110), a third planetary gearset (112, 312, 512, 712, 912, 1112), and a fourth planetary gearset (114, 314, 514, 714, 914, 1114). 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, 962, 964, 966, 968, 970, 972, 1162, 1164, 1166, 1168, 1170, 1172) may include a number of clutches (166, 168, 170, 172, 366, 368, 370, 372, 566, 568, 570, 572, 766, 768, 770, 772, 966, 968, 970, 972, 1166, 1168, 1170, 1172) and a number of brakes (162, 164, 362, 364, 562, 564, 762, 764, 962, 964, 1162, 1164). The multi-speed transmission (100, 300, 500, 700, 900, 1100) may have four planetary gearsets (108, 110, 112, 114, 308, 310, 312, 314, 508, 510, 512, 514, 708, 710, 712, 714, 908, 910, 912, 914, 1108, 1110, 1112, 1114) 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, 962, 964, 966, 968, 970, 972, 1162, 1164, 1166, 1168, 1170, 1172). The six selective couplers may include four clutches (166, 168, 170, 172, 366, 368, 370, 372, 566, 568, 570, 572, 766, 768, 770, 772, 966, 968, 970, 972, 1166, 1168, 1170, 1172) and two brakes (162, 164,362,364,562,564,762,764,962,964,1162,1164).