Multi-Planetary Transmission Coupling 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, limiting their versatility and efficiency.

Innovation Solution

The use of multiple planetary gearsets and selective couplers, including clutches and brakes, is implemented to achieve at least nine forward speed ratios and one reverse speed ratio by varying the interconnections and engagement configurations of these components, allowing for flexible torque transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing configurations of planetary gearsets and selective couplers are used, then the transmission structure is relatively simple, but the number of forward and reverse speed ratios is insufficient

Engineering Contradiction:
Improvenumber of speed ratiosVSAvoidtransmission structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The transmission system is divided into multiple independent planetary gearsets (first, second, third, and fourth planetary gearsets) that can be selectively engaged. Each planetary gearset can provide different speed ratios, and by segmenting the transmission into these modular units connected through selective couplers, the system achieves a greater number of forward and reverse speed ratios without requiring a single complex geartrain

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple planetary gearsets are arranged in a nested or串联 configuration where the output of one planetary gearset feeds into the next through interconnectors and selective couplers. This nesting allows the transmission to achieve compound speed ratios by combining the effects of multiple planetary stages, thereby increasing the total number of available ratios while maintaining a relatively organized and manageable structure

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If multiple planetary gearsets and selective couplers are added to increase speed ratios, then the versatility and efficiency are improved, but the device complexity increases

Engineering Contradiction:
Improveversatility and efficiencyVSAvoidconfiguration of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The selective couplers and interconnectors are designed to serve multiple functions: they can connect different planetary gearsets in various configurations, engage different combinations of sun gears, planet carriers, and ring gears, and provide both forward and reverse speed ratios. This multi-functionality allows the same set of components to achieve versatility and efficiency improvements without proportionally increasing device complexity

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

Solution Approach 2:

The transmission system employs dynamically engageable selective couplers that can selectively connect or disconnect different planetary gearsets and their components based on the desired speed ratio. This dynamic configuration capability allows the system to adapt its internal connections in real-time, providing versatility and efficiency improvements while maintaining a manageable structural complexity through controlled engagement rather than permanent complex linkages

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3929464B1Multi-speed planetary transmission
Publication Date: 2023.12.20 ALLISON TRANSMISSION INC
  • EP3929464B1 patent drawingFigure 1
  • EP3929464B1 patent drawingFigure 2
  • EP3929464B1 patent drawingFigure 3

AI summary

A multi-speed transmission (300) including a plurality of planetary gearsets (308, 310, 312, 314) and a plurality of selective couplers (362, 364, 366, 368, 370, 372) is disclosed. The plurality of planetary gearsets includes a first planetary gearset (308), a second planetary gearset (310), a third planetary gearset (312), and a fourth planetary gearset (314). The plurality of selective couplers includes six selective couplers (362, 364, 366, 368, 370, 372). The six selective couplers (362, 364, 366, 368, 370, 372) may include four clutches (366, 368, 370, 372) and two brakes (362, 364).