Torsional Vibration Damper Leaf Spring Deflection Compensation

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Solution Overview

Problem

The production of torsional vibration dampers is hindered by machining-induced deflections in leaf springs, leading to material distortion and increased manufacturing costs due to the need for costly and time-consuming straightening processes, which can result in high rejection rates.

Innovation Solution

The use of leaf springs with machining-induced deflections, arranged in a manner that their distortions only become apparent during static torsion, allowing for the maintenance of mean prestress and enabling the use of previously rejected material, with pairs of springs having similar deflections counterbalancing each other to ensure homogeneous damper behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If leaf springs are machined to achieve precise flexural behavior, then manufacturing precision is improved, but machining-induced deflections cause material distortion and increase manufacturing complexity

Engineering Contradiction:
Improveflexural behavior precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent converts the harmful machining-induced deflections into a beneficial feature by arranging leaf springs with similar deflections in pairs within the same chamber. The deflections, which were previously causing rejection, are now utilized to create balanced prestress conditions that improve manufacturing efficiency while maintaining functional performance

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the acceptance criterion from 'zero deflection' to 'similar deflection within acceptable range'. By modifying the parameter threshold from exact straightness to controlled variability, the patent expands the usable material pool and simplifies manufacturing while maintaining sufficient functional performance through paired arrangement

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If leaf springs are straightened to remove machining-induced deflections, then manufacturing precision is improved, but production time and costs increase

Engineering Contradiction:
Improveleaf spring straightnessVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent eliminates the need for costly and time-consuming straightening processes by accepting and utilizing machining-induced deflections. By converting what was previously a defect requiring correction into a usable characteristic, the patent significantly improves productivity while maintaining sufficient precision through the paired arrangement strategy

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent adopts a more economical approach by accepting leaf springs with machining deflections that would traditionally be rejected. This allows the use of standard machining processes without expensive post-processing, effectively treating the deflected springs as acceptable within the new design paradigm

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If leaf springs with deflections are used, then manufacturing cost is reduced, but damper performance uniformity may be affected

Engineering Contradiction:
Improvemanufacturing costVSAvoiddamper performance uniformity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent strategically arranges leaf springs with similar deflections in pairs within the same chamber, creating a localized asymmetric compensation system. This paired arrangement ensures that springs with comparable deflections work together to maintain balanced prestress, while different chambers can have different paired configurations, achieving overall uniformity through controlled local asymmetry

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies different arrangements of leaf spring pairs in different chambers to compensate for local variations in machining deflections. Each chamber's paired springs are matched to their specific deflection characteristics, creating locally optimized configurations that collectively ensure uniform damper performance across the entire assembly

Inventive Principle:
Principle #3Local quality

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 approach simplifies the manufacturing process, reduces costs, and allows for the use of previously waste material, maintaining the functionality and flexibility of the torsional vibration damper without affecting its characteristic curve under no-load conditions.

Implementation Method 1

The torque transmission between the inner part and the outer housing is carried out flexibly by means of the leaf spring configurations

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

With a relative rotation between the inner part and the outer housing, the displacement of the damping medium between the outer housing and the inner part causes a damping effect

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2206933B1Torsional vibration damper
Publication Date: 2015.06.24 GEISLINGER GROUP GMBH
  • EP2206933B1 patent drawingFigure 1
  • EP2206933B1 patent drawingFigure 2
  • EP2206933B1 patent drawingFigure 3

AI summary

A torsional vibration damper comprises an outer housing (11), an inner part (12) that is concentric relative to the outer housing (11), a plurality of chambers (13) formed between the outer housing (11) and the inner part (12), which arc filled with a damping medium and are connected to one another through overflow channels (14), and a plurality of leaf spring configurations (16, 17, 16', 17') that are arranged in the chambers (13) and join the outer housing (11) and the inner part (12) with one another in a torsionally flexible manner. The leaf spring configurations (16, 17, 16', 17') have machining-induced deflections. Two leaf springs with substantially similar deflections are each arranged within a chamber (13). The leaf spring pairs may be arranged in a mirror-image array or in parallel to one another. Thus, the manufacturing cost of a torsional vibration damper can be reduced, while its compact outer dimensions can be maintained.