Trapezoidal Synchronizer Ring Pressure Piece Gear Rattle

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Solution Overview

Problem

Synchronizer rings in motor vehicle manual transmissions often produce noise due to backlash, leading to gear rattle, increased drag torque, and potential damage from relative movements and friction issues.

Innovation Solution

The synchronizing ring is designed with a trapezoidal index tab and a pressure piece featuring a corresponding receiving recess with undercuts, ensuring a defined press against the synchronizing hub, which minimizes or eliminates noise and drag torque by creating a resultant force that attracts the rings to the hub.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a compensating lever is pivotably mounted to avoid gear rattle, then the gear rattle is reduced, but the device complexity increases

Engineering Contradiction:
Improvegear rattleVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the harmful relative movements between the synchronizing ring and hub by introducing a dedicated pressure piece that applies axial force to press the synchronizing ring against the hub, separating the noise reduction function from the complex compensating lever mechanism

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pressure piece acts as an intermediary element between the synchronizing ring and hub, applying controlled axial force to eliminate backlash and prevent gear rattle without requiring the synchronizing ring itself to have complex compensating mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the synchronizing ring is pressed against the synchronizing hub, then the gear rattle is reduced, but the drag torque increases

Engineering Contradiction:
Improvegear rattleVSAvoiddrag torque
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The pressure piece applies partial axial force only when needed to eliminate backlash and prevent gear rattle, rather than maintaining continuous excessive pressure that would increase drag torque during normal operation

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The axial force applied by the pressure piece can vary depending on operational conditions, allowing optimization between preventing gear rattle and minimizing drag torque through dynamic adjustment of the pressing force

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the index tab engages with play in the receiving recess, then the manufacturing is easier, but the relative movements cause damage and noise

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The pressure piece applies preliminary axial force to press the synchronizing ring against the hub before damaging relative movements can occur, preventing the harmful effects of play in the index tab engagement while maintaining easy manufacturing

Inventive Principle:
Principle #9Preliminary anti-action

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 effectively reduces or eliminates gear rattle and drag torque, preventing damage to the friction lining and index cams, while maintaining the locking position and reducing noise.

Implementation Method 1

a ball or ball pin-compression spring arrangement (18)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a peripheral force occurs between the synchronizing ring and the pressure piece, with the interacting trapezoidal surfaces of the recess and the projection being inclined in such a way that an axial force results from this peripheral force

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2194286B1Synchronising device
Publication Date: 2012.02.22 HOERBIGER ANTRIBSTECHNIK GMBH
  • EP2194286B1 patent drawingFigure 1
  • EP2194286B1 patent drawingFigure 2~4

AI summary

The synchronizing device (20) has a synchronous body (10) with an external toothing (11), in which a pressure piece (15,16,17) is arranged. The synchronizing device has a clutch sleeve (13) which is guided on the synchronous body and a synchronizer ring (1,1 ') with an index lobe (6,7,8). The pressure piece has a trapezoidal receiving recess facing the synchronizer ring, in which the corresponding trapezoidal index lobe engages.