Dual-Clutch Transmission Reverse Gear Space Reduction

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Solution Overview

Problem

Existing dual-clutch transmissions require an additional wheel set for the reverse gear, which increases installation space and complexity, and the gear change for reverse gear often involves separate sub-transmissions, complicating the design and increasing size.

Innovation Solution

The transmission design outsources the reverse gear using existing drive and output gears from forward gears, eliminating the need for a separate wheel set by incorporating a reverse gear shaft with an input and output gear that meshes with the input and countershaft gears, allowing gear changes to occur exclusively through clutch switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a separate wheel set is provided for the reverse gear, then the reverse gear can be realized, but additional installation space is required

Engineering Contradiction:
Improvereverse gear functionalityVSAvoidinstallation space
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent applies multi-functionality by making existing drive gears and output gears serve dual purposes: they transmit power for forward gears and simultaneously enable reverse gear operation. The input gear on the reverse gear shaft meshes with existing drive gears, while the output gear meshes with existing output gears, allowing these components to function for both forward and reverse motion without requiring dedicated reverse gear components.

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

Solution Approach 2:

The patent merges the reverse gear functionality into the existing forward gear structure. Instead of providing a separate wheel set, the reverse gear shaft and its gears are integrated with the existing drive and output gears, combining multiple functions into a unified transmission system that reduces overall space requirements.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If an additional wheel set is provided for the reverse gear, then the reverse gear can be implemented, but the device complexity increases

Engineering Contradiction:
Improvereverse gear capabilityVSAvoidtransmission structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent reduces device complexity by making existing components multi-functional. The drive gears and output gears that originally served only forward gear operations now also enable reverse gear operation, eliminating the need for additional dedicated reverse gear components and simplifying the overall transmission structure.

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

Solution Approach 2:

The patent extracts the reverse gear functionality from the conventional separate wheel set approach and integrates it into the existing transmission structure. By removing the requirement for additional dedicated reverse gear components and incorporating reverse operation into the existing gear meshing arrangement, the overall device complexity is reduced.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If gear change for reverse gear involves separate sub-transmissions, then reverse gear operation is achieved, but the design complexity and size increase

Engineering Contradiction:
Improvereverse gear operationVSAvoidsub-transmission structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the reverse gear operation into the existing single transmission structure. The reverse gear shaft with its input and output gears is integrated with the existing drive and output gears, allowing reverse gear operation to occur within the same transmission housing and gear arrangement, eliminating the need for separate sub-transmissions.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2428699B1Double-clutch transmission with displaced reverse gear
Publication Date: 2014.12.17 DR ING H C F PORSCHE AG
  • EP2428699B1 patent drawingFigure 1
  • EP2428699B1 patent drawingFigure 2
  • EP2428699B1 patent drawingFigure 3

AI summary

The gear transmission (1) has multiple front gears and one reverse gear, where the input shafts (7,8) are provided with pinions (16,17,18,19,20,21). Two layshafts (9,10) are provided with output drive gears (22,23,24,25,26,27,28,29) designed as idlers and the other pinions (30,31). The pinions of the input shafts cog with the output drive gears and the pinions of the layshafts cog an output shaft. A reverse gear shaft (34) is provided with an input gear (35) and an output gear (36).