Three-Planetary Transmission with Locking Mechanisms for Shift Continuity

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Solution Overview

Problem

The operational demands for a gearbox in electrically propelled working machines differ significantly from those in conventionally internal combustion engine (ICE) propelled vehicles, requiring an improved transmission arrangement to optimize performance in rough terrain and accommodate the distinct speed range differences.

Innovation Solution

A three-stage transmission arrangement is introduced, comprising multiple planetary gear sets and locking mechanisms, allowing for rapid and smooth gear shifting while maintaining power transfer, with the option to connect two prime movers for reduced power requirements and increased motive power, and featuring a gear selection system that uses locking mechanisms and fluid pressure control for efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional gearbox is used in electrically propelled working machines, then the transmission arrangement can handle the speed range of internal combustion engines, but it cannot optimize performance for electric machines with different speed ranges

Engineering Contradiction:
Improveadaptability to electric machine speed rangeVSAvoidoperational performance in rough terrain
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The transmission arrangement is divided into three separate planetary gear sets (first, second, and third planetary gear sets), each capable of providing different gear ratios. This segmentation allows the system to be optimized for the specific speed range characteristics of electric machines while maintaining reliable operation in rough terrain conditions.

Inventive Principle:
Principle #1Segmentation

2Speed

If gear shifting is performed in a conventional transmission, then speed changes can be achieved, but power transfer is interrupted and wear increases

Engineering Contradiction:
Improvegear shifting speedVSAvoidpower transfer interruption and wear
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The transmission arrangement enables continuous power transfer during gear shifting operations by maintaining engagement between the input shaft and the planetary gear sets throughout the shifting process. This eliminates interruptions in power flow and reduces wear on transmission components.

Inventive Principle:
Principle #20Continuity of useful action

3Device complexity

If a single prime mover is used, then the powertrain is simpler, but the power requirements cannot be optimized for different operating conditions

Engineering Contradiction:
Improveprime mover configurationVSAvoidmotive power and power requirements
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The transmission arrangement is designed to accommodate one or two prime movers, making it a multi-functional system that can be configured based on specific power requirements. This universality allows optimization of the powertrain for different operating conditions while maintaining a relatively simple base configuration.

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

Data Source

PatentEP4075021B1A transmission arrangement
Publication Date: 2023.10.18 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP4075021B1 patent drawingFigure 1
  • EP4075021B1 patent drawingFigure 2
  • EP4075021B1 patent drawingFigure 3

AI summary

The present invention relates to a transmission arrangement, comprising a first planetary gear set, a second planetary gear set, a third planetary gear set, an input shaft connectable to a prime mover, the input shaft being operatively connected to a sun gear of the second planetary gear set and to a sun gear of the third planetary gear set, an output shaft operatively connected to a ring gear of the first planetary gear set and to a planet carrier of the second planetary gear set. The transmission arrangement further comprises a gear selection arrangement comprising a first locking mechanism connected to a planet carrier of the first planetary gear set, a second locking mechanism connected to a sun gear of the first planetary gear set, a ring gear of the second planetary gear set and to a planet carrier of the third planetary gear set, and a third locking mechanism connected to a ring gear of the third planetary gear set.