Torsional Vibration Damper Stop Geometry for Low-Noise Absorber Masses

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Solution Overview

Problem

Torsional vibration dampers experience intolerable impact noise when the centrifugal force acting on absorber masses falls below their weight, causing absorber masses to fall and collide with stops, leading to noise issues during vehicle crawling or engine shutdown.

Innovation Solution

A torsional vibration damper design with absorber masses featuring geometric projections and stop pickups, where the first and second contact areas are adapted to the stop profiles, allowing for low-noise stopping behavior, and the stops are accommodated on a common ring-shaped component with axial offset holders to enhance damping properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If absorber masses are allowed to move freely on the absorber mass carrier, then the torsional vibration damper can effectively damp vibrations during operation, but impact noise occurs when centrifugal force drops below weight causing absorber masses to fall and collide with stops

Engineering Contradiction:
Improvevibration damping effectivenessVSAvoidimpact noise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies beforehand cushioning by providing a geometric projection on the absorber mass that includes a first contact area and a second contact area. The first contact area is designed to contact the stop before the absorber mass can fall and collide, while the second contact area provides additional cushioning contact with the stop pickup. This pre-cushioning design prevents the harmful impact noise by ensuring controlled, gradual contact rather than sudden collision.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The geometric projection acts as an intermediary element between the absorber mass and the stop/stop pickup. Instead of the absorber mass directly colliding with the stop, the geometric projection with its specifically shaped contact areas mediates the interaction, distributing the contact force and preventing direct impact. This intermediary structure enables controlled stopping behavior while maintaining vibration damping functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If stops are provided to limit absorber mass movement, then impact noise can be reduced, but the stopping behavior may not be sufficiently controlled without proper geometric adaptation

Engineering Contradiction:
Improveimpact noiseVSAvoidstopping behavior control
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by providing specific geometric projections on the absorber mass with differentiated contact areas. The first contact area is specifically designed to contact the stop with certain geometric properties, while the second contact area is designed to contact the stop pickup with different geometric properties. This localized geometric adaptation ensures that each contact point provides the appropriate stopping behavior, achieving both noise reduction and reliable control.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The geometric projection incorporates curved surfaces that are adapted to the profiles of the stop and stop pickup. These curved contact areas enable smooth, controlled contact rather than sharp impacts. The curvature allows the absorber mass to gradually engage with the stopping mechanism, ensuring reliable and controlled stopping behavior while minimizing impact noise.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

Prevents impact noise by ensuring controlled contact between absorber masses and stops, maintaining quiet operation even when centrifugal force drops below the weight force, and enhances damping properties through increased resilience and radial support.

Implementation Method 1

the effective speed on the hub disc and thus the centrifugal force acting on the absorber masses will drop rapidly when the respective drive, such as an internal combustion engine, is switched off

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the at least one absorber mass having a stop side with a geometric projection, and the at least one absorber mass each having at least one Stop is assigned, which has an at least partial axial overlap with the at least one absorber mass

Methodology Applied
Scientific EffectImpact noise: Impact Force

Data Source

PatentEP2912340B2Torsional vibration damper
Publication Date: 2021.04.14 ZF FRIEDRICHSHAFEN AG
  • EP2912340B2 patent drawingFigure 1
  • EP2912340B2 patent drawingFigure 2
  • EP2912340B2 patent drawingFigure 3~4

AI summary

A torsional vibration damper is designed with an absorption mass carrier on which at least one absorption mass which is movable relative to same is accommodated, and with at least one stop, wherein the at least one absorption mass has a stop side with a geometrical formation. The at least one absorption mass is assigned at least one stop which has an at least partial axial overlap with the at least one absorption mass in the direction of extent of a central axis and which, on the side thereof facing the stop side of the absorption mass, has a stop profile, wherein the at least one stop for the at least one absorption mass is assigned at least one stop receiver. A geometrical formation provided on the at least one absorption mass has both a first contact region which is at least substantially effective in the radial direction and a second contact region which is effective at least substantially in the tangential direction, of which the first contact region can be set into operative connection with the stop and the second contact region can be set into operative connection with the stop receiver.