Planetary Multi-Speed Transmission for High Ratio Coverage

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Solution Overview

Problem

Current multiple speed transmissions face challenges in achieving a high number of gear ratios with improved performance, cost efficiency, responsiveness, and packaging, particularly in military tracked vehicles requiring high ratio coverage and low transmission losses across varying speeds.

Innovation Solution

The design incorporates multiple planetary gearsets and torque-transmitting mechanisms that can be selectively engaged in various combinations to achieve at least ten forward and one reverse speed ratio, allowing for adaptable packaging on single or parallel axes, utilizing a combination of planetary gearsets and torque-transmitting mechanisms to optimize gear ratios and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple planetary gearsets and torque-transmitting mechanisms are used to achieve high number of gear ratios, then the number of speed ratios is improved, but the device complexity increases

Engineering Contradiction:

Improvenumber of speed ratiosVSAvoidtransmission architecture complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple planetary gearsets (first, second, third, and fourth planetary gearsets) with multiple torque-transmitting mechanisms (first through seventh mechanisms) into a unified transmission architecture. This merging allows the system to achieve at least ten forward speed ratios and one reverse speed ratio through coordinated engagement of these components, resolving the contradiction by integrating multiple elements into a cohesive multi-ratio transmission system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The transmission system is segmented into distinct functional modules: multiple planetary gearsets (each with sun gears, ring gears, and carrier members) and multiple torque-transmitting mechanisms. Each segment can be selectively engaged to achieve different speed ratios, allowing the system to provide high adaptability while managing complexity through modular organization of components.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If multiple torque-transmitting mechanisms are selectively engaged to achieve multiple speed ratios, then the adaptability is improved, but the device complexity increases

Engineering Contradiction:

Improvespeed ratio variabilityVSAvoidnumber of torque-transmitting mechanisms

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The torque-transmitting mechanisms are designed with multi-functionality, where each mechanism can engage different combinations of planetary gearset components (sun gears, ring gears, carrier members) to achieve various speed ratios. This universality allows a finite number of mechanisms to provide extensive adaptability across ten forward and one reverse speed ratio, reducing the need for additional specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Volume of moving object

If a compact transmission design is implemented for military vehicles, then the packaging is improved, but the number of components may increase

Engineering Contradiction:

Improvetransmission packaging volumeVSAvoidnumber of planetary gearsets and mechanisms

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The planetary gearsets are arranged in a nested configuration where the first, second, third, and fourth planetary gearsets are positioned along a common axis in a compact sequence. This nesting allows multiple gearsets to occupy minimal space while maintaining their functional independence, achieving compact packaging suitable for military vehicle applications despite the presence of multiple components.

Inventive Principle:

Principle #7Nested doll (Nesting)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enables efficient torque transfer across a wide range of speeds with reduced losses, providing a compact and adaptable transmission solution suitable for military applications.

Implementation Method 1

first, second, third and fourth planetary gearsets each having first, second and third members; a plurality of interconnecting members each connected between at least one of the first, second, third, and fourth planetary gearsets

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

a first torque-transmitting mechanism selectively engageable to interconnect the first member of the first planetary gearset and the first member of the second planetary gearset with a stationary member

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS11686373B2Multi-speed transmission

Publication Date: 2023.06.27 ALLISON TRANSMISSION INC

AI summary

A multiple speed transmission includes an input member, an output member, first, second, third and fourth planetary gearsets each having first, second and third members, and a plurality of interconnecting members each connected between at least one of the first, second, third, and fourth planetary gearsets and at least another of the first, second, third, and fourth planetary gearsets. The transmission includes a plurality of torque-transmitting mechanisms between the input and output members, wherein the torque transmitting mechanisms are selectively engageable in combinations of at least four to establish at least ten forward speed ratios between the input member and the output member.