Automatic Transmission Switching Assembly Radial Coupling Arrangement

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Solution Overview

Problem

Automatic transmissions face high component costs due to planetary gear sets and multi-disc clutches or brakes, necessitating a cost-effective and space-efficient switching assembly for coupling a drive assembly with an output assembly.

Innovation Solution

A switching assembly with a rotatable and axially displaceable switching unit, featuring a ring-shaped force transmission element with internal teeth and a synchronization ring, allowing for compact arrangement and efficient coupling between the drive and output assemblies via positive and frictional couplings, with the ability to switch between different drive speed ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple planetary gear sets and multi-plate clutches are used to achieve various gear ratios, then the transmission functionality and reliability are improved, but the component expenditure and device complexity increase significantly

Engineering Contradiction:
Improvetransmission functionalityVSAvoidcomponent expenditure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the frictional coupling (multi-plate clutch) and positive coupling (dog clutch) into a single integrated shift assembly. The frictional coupling plates are arranged axially adjacent to the positive coupling elements, allowing both coupling types to perform gear ratio switching functions within one compact unit, thereby reducing the number of separate components while maintaining transmission reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shift assembly serves multiple functions: the frictional coupling enables smooth torque transfer and speed adjustment, while the positive coupling provides locked gear ratio selection. This multi-functional design eliminates the need for separate clutch and dog clutch assemblies, reducing component expenditure while achieving diverse gear ratios

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

2Volume of moving object

If a compact shift assembly design is implemented with radial arrangement of coupling elements, then the space utilization and cost-effectiveness are improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveshift assembly spaceVSAvoidcoupling alignment precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent transitions from axial arrangement to radial arrangement of coupling elements relative to the transmission axis. The frictional coupling and positive coupling are positioned on different radii, enabling compact radial packing within the transmission housing while maintaining functional independence of each coupling type

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The shift unit acts as an intermediary component that mediates between the frictional coupling and positive coupling. It includes elements such as synchronization rings and shifting forks that facilitate precise alignment and coordinated operation of the radially arranged coupling elements, thereby managing manufacturing precision requirements

Inventive Principle:
Principle #24Intermediary (Mediator)

3Area of stationary object

If the force transmission element is arranged outside the non-positive coupling element radially, then the compact design and space efficiency are improved, but the structural complexity of the coupling arrangement increases

Engineering Contradiction:
Improvetransmission housing spaceVSAvoidcoupling arrangement structure
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The shift assembly is segmented into distinct functional zones: the non-positive coupling element (dog clutch) is positioned on one radius while the force transmission element (frictional coupling) is positioned on a different radius. This segmentation allows each element to be optimized independently while fitting within the available transmission housing space

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The radially arranged coupling elements are nested within the transmission housing in a compact configuration. The frictional coupling plates and dog clutch elements are positioned at different radial distances from the transmission axis, creating a nested-like arrangement that maximizes space utilization while managing structural complexity

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

Enables a compact, cost-effective installation of the switching assembly within the transmission housing, allowing for efficient speed synchronization and torque transmission without interruptions, reducing component costs and improving transmission efficiency.

Implementation Method 1

a synchronization ring (7) having at least two friction surfaces (10a, b, 11, 12)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3449159B1Automatic transmission with a shift assembly
Publication Date: 2023.11.22 VOITH PATENT GMBH
  • EP3449159B1 patent drawingFigure 1~2
  • EP3449159B1 patent drawingFigure 3~5

AI summary

The invention relates to a switching module (1) for coupling a drive module (2) to an output module (3) in an automatic transmission (4) for a motor vehicle, said modules being mounted in a rotatable manner about a common transmission axis (A). The switching module comprises a switching unit (5) which can be rotated about the transmission axis (A) and which is coupled to one of the modules (2, 3) in a movable and rotationally fixed manner. The switching unit (5) comprises an element (8) for coupling the drive module (2) and the output module (3) in a force-fitting manner and an element (7) for coupling the drive module (2) and the output module (3) in a form-fitting manner. The aim of the invention is to allow a space-saving and inexpensive arrangement of the switching module (1). This is achieved in that the force transmission element (8) for a form-fitting coupling is to be arranged outside of the element (7) for the force-fitting coupling with respect to the transmission axis A when seen in the radial direction.