Parallel Gearbox Shifting Under Load

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Solution Overview

Problem

Agricultural work vehicles require transmission arrangements that can cover a wide range of driving speeds with a large number of gears, but existing designs often necessitate an interruption in traction when shifting between gear groups, limiting driving comfort and operational flexibility.

Innovation Solution

A transmission arrangement featuring a parallel shift transmission with coaxial output shafts and a range shift transmission with multiple shift groups, allowing for shifting between groups under load by preselecting a switching group via one output shaft and connecting it to the countershafts, enabling seamless power flow and gear usage across all main manual transmission stages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional range transmission with single output shaft is used, then the structure is simple, but shifting between gear groups requires interruption in traction

Engineering Contradiction:

Improvecontinuous power transmissionVSAvoidtransmission structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The transmission system is segmented into two independent parallel output shafts (first output shaft and second output shaft), each capable of receiving power from countershafts and driving separate shift groups. This segmentation allows one shaft to maintain power transmission while the other shaft undergoes shifting operations, eliminating the need for traction interruption during gear group changes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system preselects a target shift group on the second output shaft before actually switching to it. The preselection mechanism prepares the desired gear group in advance on the standby shaft, so when the shaft switching occurs, the transition is seamless and maintains continuous power flow to the vehicle wheels.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If all shift groups are connected to a single output shaft, then the structure is simpler, but gear changing between groups cannot be performed under load

Engineering Contradiction:

Improvegear shifting under loadVSAvoidshaft configuration

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dual parallel output shaft design ensures that while one shaft is engaged in shifting operations (useless action temporarily), the other shaft continues to transmit power continuously (useful action). This maintains uninterrupted power flow to the vehicle wheels throughout the entire gear group changing process.

Inventive Principle:

Principle #20Continuity of useful action

3Adaptability or versatility

If multiple countershafts are used in parallel transmission, then more gear ratios are available, but the axial length increases

Engineering Contradiction:

Improvegear ratio rangeVSAvoidaxial length

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

Instead of extending the transmission system axially to accommodate multiple countershafts and shift groups, the invention utilizes the radial dimension by implementing a dual parallel output shaft configuration. The two output shafts are arranged coaxially or in parallel within the same axial space, allowing multiple gear groups to be accessed without increasing the axial length of the transmission housing.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3091253B1Gearbox assembly

Publication Date: 2020.04.01 DEERE & CO

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AI summary

Transmission arrangement (30), in particular for an agricultural work vehicle (10), comprising a parallel transmission (50) with an input shaft (52) from which drive power can be distributed via a first and a second shift element (54-1, 54-2) to respective countershafts (56-1, 56-2), and a first and a second coaxially arranged output shaft (581, 582), wherein the drive power can be transmitted from each of the countershafts (56-1, 56-2) to each of the output shafts (58-1, 58-2 or 90-1, 90-2) as required, a range transmission (80) with several shift groups (82-1, 82-2,...), wherein a first of the shift groups (82-1) is connected to the first of the output shafts (58-1) and a second of the shift groups (82-1) is connected to the second of the output shafts (58-2) It can be connected to a drive. Fig. 3