Multi-Group Transmission Power Shifting via Segmented Load Paths

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing multi-group transmissions for commercial vehicles, such as trucks, face limitations in power-shiftable capabilities, particularly in the main group, which restricts gear shifting and provides only eight gears, and require load interruptions for gear changes, while dual-clutch transmissions offer limited power-shifting options due to single load paths and lack of neutral positions.

Innovation Solution

A multi-group transmission design featuring a splitter group, main group, and range group with double clutches and coaxial countershafts, enabling fully power-shiftable operations across all forward and reverse gears through separate load paths and overlap shifting, allowing for seamless gear changes without additional clutches and neutral positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a multi-group transmission has only one load path in the main group, then the structure is simpler, but the main group cannot be power-shifted and only eight gears are provided

Engineering Contradiction:

Improvetransmission structureVSAvoidpower-shifting capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The transmission is divided into splitter group, main group, and range group, each with separate load paths. The main group specifically has two separate load paths (first and second load paths) that can be independently engaged, enabling power-shifting capability while maintaining structural organization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The transmission employs nested shaft structures with a first hollow countershaft and a second countershaft arranged in sections in the first countershaft. This nesting allows multiple load paths to coexist within a compact structure, providing both simplicity and power-shifting capability.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of operation

If gears are changed by load interruption, then the switching element can have three quasi-active positions, but power shifts are limited and require load interruption to switch to the third main group gear

Engineering Contradiction:

Improvegear shifting operationVSAvoidpower-shifting capability

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The double clutch system pre-engages the next gear on the open clutch before the current gear is disengaged. This overlap shifting allows the transmission to prepare for the next gear change in advance, enabling power-shifting without load interruption and eliminating the need for neutral positions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The two clutches of the double clutch are arranged to overlap in time, ensuring continuous power transmission during gear changes. The first clutch engages the next gear while the second clutch is still engaged, maintaining uninterrupted power flow and enabling true power-shifting capability.

Inventive Principle:

Principle #20Continuity of useful action

3Adaptability or versatility

If a dual clutch transmission is used, then power-shifting is enabled in splitter and range groups, but the main group remains limited with only one load path

Engineering Contradiction:

Improvepower-shifting capabilityVSAvoidload path configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #7Nested doll (Nesting)

4Productivity

If overlap shift of double clutch is used, then seamless gear changes are enabled, but the structure becomes more complex with additional clutches

Engineering Contradiction:

Improvegear shifting efficiencyVSAvoidclutch configuration

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The double clutch system serves multiple functions: it enables overlap shifting for seamless gear changes, provides two separate load paths for power-shifting capability, and eliminates the need for neutral positions. This multi-functionality justifies the additional complexity by consolidating multiple features into a single system.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP2916036B1Multi-group transmission with a double clutch

Publication Date: 2018.07.18 MAN TRUCK & BUS SE

Figure 1~2
Figure 3
Figure 4~5

AI summary

The invention relates to a multi-group transmission (100), preferably a dual-clutch transmission, for a commercial vehicle. The multi-group transmission (100) comprises a split group (SG), preferably with a first split constant (Z1), a second split constant (Z2), and a third split constant (Z3), a main group (HG), preferably with exactly two main group forward gears, and a range group (RG). The multi-group transmission (100) is characterized in particular by the fact that the split group (SG) and the main group (HG) each comprise two separate load paths and are, in particular, fully load-shiftable.