Segmented Synchronizer Friction Ring for Controlled Axial Positioning

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Solution Overview

Problem

The existing segmented friction rings for synchronization units in gear change transmissions face issues with uncontrolled axial positioning during synchronization, leading to uneven stress and wear on mounting surfaces, increased mechanical stress, and reduced reliability and accuracy of the synchronization process.

Innovation Solution

A friction ring design with a conical body featuring a separating point where the first and second separating surfaces touch, forming a closed contour, allowing elastic deformation only in the direction of a larger circumference, ensuring controlled axial positioning and reduced mechanical stress, and incorporating circumferential prestress to maintain surface contact under applied forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the friction ring body is segmented with a slot formed perpendicularly to the axis, then the friction ring can expand towards a larger circumference to avoid self-locking, but the friction ring cannot be clearly positioned relative to the synchronizer ring in the axial direction, leading to uncontrolled axial positioning and uneven stress on mounting surfaces

Engineering Contradiction:
Improveavoid self-lockingVSAvoidaxial positioning precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The friction ring body is divided into at least two separate friction ring segments that are displaceable relative to each other in the axial direction. This segmentation allows the friction ring to expand towards a larger circumference while maintaining controlled axial positioning through the interaction between segments and the synchronizer ring's conical inner installation surface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution transitions from a single-plane slot design to a multi-dimensional segment arrangement where segments can move independently in the axial direction. This dimensional change enables the friction ring to simultaneously achieve circumferential expansion for preventing self-locking and axial positioning control through the conical surface interaction.

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

2Measurement precision

If the friction ring is designed to allow elastic deformation in the circumferential direction to prevent self-locking, then the synchronization accuracy may improve, but the axial positioning becomes uncontrolled leading to increased mechanical stress and wear

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidmechanical stress and wear
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The friction ring segments are designed to be displaceable relative to each other in the axial direction, creating a dynamic structure that can adapt to operational conditions. This dynamic arrangement allows controlled elastic deformation in the circumferential direction for synchronization accuracy while the axial displacement capability maintains controlled positioning, preventing excessive mechanical stress and wear.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the friction ring body is formed as a single segment instead of multiple segments, then the structure is simpler, but the friction ring cannot expand towards a larger circumference to avoid self-locking

Engineering Contradiction:
Improvefriction ring structureVSAvoidself-locking prevention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The friction ring body is divided into at least two separate friction ring segments that can move relative to each other axially. This segmentation enables the friction ring to expand towards a larger circumference, preventing self-locking, while maintaining a relatively simple overall structure that is easier to manufacture and assemble compared to a fully complex multi-component design.

Inventive Principle:
Principle #1Segmentation

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

This design enables precise axial positioning of the friction ring relative to the synchronizer ring, reducing wear and mechanical stress, improving shift quality, and maintaining synchronization accuracy while preventing self-locking on the inner friction surface.

Implementation Method 1

the friction ring body (4) is elastically deformable in the circumferential direction U in such a way that a circumference (13) of the friction ring (1) can be enlarged

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The friction ring body (4) is prestressed in the circumferential direction U in such a way that the first separating surface (7) and the second separating surface (8) touch under the circumferential prestress (14)

Methodology Applied
Scientific EffectPrestress:

Implementation Method 3

The inner friction surface (401) extends conically at a predeterminable friction angle α1 along the friction ring axis (6)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3153732B1Friction ring for a synchronizing unit
Publication Date: 2023.06.07 OERLIKON FRICTION SYST GERMANY
  • EP3153732B1 patent drawingFigure 1a~1b
  • EP3153732B1 patent drawingFigure 1c~1d
  • EP3153732B1 patent drawingFigure 1e

AI summary

The invention relates to a friction ring (1) for a synchronization unit of a gear-shift transmission. The friction ring (1) comprises a conical friction ring body (4) with an inner friction surface (401) and an outer mounting surface (402), which each define the friction ring body (4) in a radial direction perpendicular to an axial friction ring axis (6). The friction ring body (4) is interrupted in a circumferential direction (U) extending around the friction ring axis (6) by a separation point (5) such that a first separation surface (7) and a second separation surface (8) are formed at the separation point (5). In order for the friction ring (1) to assume a controlled axial position relative to a synchronizer ring during synchronization, the first separation surface (7) and the second separation surface (8) contact each other in a predefinable area such that the friction ring body (4) is formed in the form of a circumferentially closed contour (U) with a minimum circumference (13).