Synchronizer Ring Centering Tab Geometry for Crack-Free Bending

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Solution Overview

Problem

The existing methods for producing synchronizing rings often result in centering lugs with cracks or creases due to the narrow space required for bending, necessitating additional laser welding for strength, which increases effort and cost.

Innovation Solution

The centering tabs are reshaped to have a maximum first thickness greater than a second thickness, allowing for bending without folds or cracks, and are firmly attached to the cone body post-bending, eliminating the need for additional welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the centering lugs are bent in a narrow space of the die, then the synchronizing ring can be produced with conventional tools, but the centering lugs develop cracks on their radially outer underside and/or creases in the area of connection to the cone body

Engineering Contradiction:
Improvebending processVSAvoidcentering lug integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The centering lugs are pre-formed with a stepped cross-section before bending, creating a geometric feature that prevents stress concentration during the bending operation. The first section (thicker) remains straight while the second section (thinner) is bent, and the step between sections absorbs bending stresses that would otherwise cause cracks or creases.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The centering lug is given non-uniform thickness through the stepped cross-section, with the first section having greater thickness than the second section. This local variation in geometry is strategically placed at the bend location to provide structural reinforcement exactly where needed during the bending operation.

Inventive Principle:
Principle #3Local quality

2Strength

If additional laser welding is applied to strengthen the centering bracket connection, then the connection strength is improved, but the production effort and cost increase

Engineering Contradiction:
Improvecentering bracket connectionVSAvoidproduction process
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The stepped cross-section geometry of the centering lug inherently provides the strength needed for the connection to the cone body. The thicker first section acts as a built-in reinforcement that maintains connection integrity during bending and operation, eliminating the need for additional welding processes.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The cross-sectional dimensions of the centering lug are varied along its length to create the stepped structure. This geometric parameter change provides the necessary structural strength without requiring additional joining processes or materials.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3581290B1Method for manufacturing a synchroniser ring
Publication Date: 2021.03.03 DIEHL METAL STIFTUNG & CO KG
  • EP3581290B1 patent drawingFigure 1~2
  • EP3581290B1 patent drawingFigure 3a~3e
  • EP3581290B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for manufacturing a synchronizer ring (1) with a conical body (2) and at least one centering tab (3) provided on its outer circumference, wherein the method comprises the following steps: manufacturing the centering tab (5) extending radially from the conical body (2) by punching, and bending the centering tab (5) in the direction of the conical body (2), so that after bending a radially outer underside (6) of the centering tab (5) lies section by section within the predetermined centering radius (Z). To improve the strength of the centering tab (5), it is proposed that the centering tab (5) be reshaped before the bending step such that a radially inner first section (A1) of the centering tab (5) connected to the cone body (2) has a maximum first thickness (d1) which is greater than a maximum second thickness (d2) of a second section (A2) extending radially from the first section (A1).