Torsional Damper Spring Package With Conical Coil Spring Centering

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Solution Overview

Problem

Existing spring packages experience increased friction and wear due to the lateral mobility of coil springs relative to support elements, which affects their positioning and efficiency in torsion dampers.

Innovation Solution

The spring package incorporates conical centering surfaces on the support elements and coil springs, which align and secure the coil springs axially and laterally, reducing unwanted mobility and wear by ensuring a defined arrangement and optimal force introduction, even under tension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If coil springs are arranged on stepped sections with intermediate surfaces, then the spring assembly can accommodate multiple coil springs with different lengths and diameters, but the coil springs exhibit lateral mobility relative to the support element which increases friction and wear

Engineering Contradiction:
Improveaccommodation of multiple coil springs with different dimensionsVSAvoidlateral alignment stability of coil springs
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs conical centering surfaces instead of flat intermediate surfaces. The conical geometry provides curved contact surfaces that guide the coil springs radially inward toward the central axis, eliminating lateral mobility while accommodating springs of different dimensions. The conical shape creates a self-centering effect through geometric constraint.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The centering surfaces act as intermediary elements between the coil springs and the support element. These specialized surfaces mediate the interaction by providing radial guidance and axial positioning, separating the functions of spring mounting from lateral constraint, thereby reducing friction and wear while maintaining adaptability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If coil springs are allowed to move laterally relative to the support element, then the spring assembly can absorb torsional movements, but this lateral mobility causes increased friction and wear of the spring assembly

Engineering Contradiction:
Improvetorsional movement absorptionVSAvoidfriction and wear of spring assembly
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The conical centering surfaces provide curved guidance that allows controlled radial movement for torsional absorption while preventing harmful lateral mobility. The geometric shape enables the springs to move within defined conical paths, reducing friction by maintaining optimal contact angles and preventing scraping against flat surfaces.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the support element surfaces from flat to conical. This parameter change transforms the contact mechanics, allowing the springs to absorb torsional movements through controlled deformation while the conical geometry maintains proper alignment and reduces frictional losses during operation.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the coil springs are secured with preloading forces, then the positioning is improved, but this requires additional force and may increase the complexity of the spring assembly

Engineering Contradiction:
Improvepositioning precision of coil springsVSAvoidcomplexity of spring assembly structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The conical centering surfaces provide geometric self-centering that achieves precise positioning without requiring complex preloading mechanisms. The conical geometry naturally guides the springs to their correct positions through shape complementarity, eliminating the need for additional securing elements or complex assembly procedures.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The centering surfaces enable the spring assembly to self-center and self-position during assembly and operation. The geometric constraint provided by the conical surfaces automatically aligns the springs without requiring external preloading forces or complex securing mechanisms, simplifying the overall assembly structure.

Inventive Principle:
Principle #25Self-service

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 reduces friction and wear, improves the alignment and positioning of coil springs, and enhances the torsional rigidity of the torsion damper, allowing for increased engine torque transmission or improved rotational decoupling.

Implementation Method 1

A first centering surface is formed on the support element, in particular on the step of the step section, which corresponds to a second centering surface of the coil spring and cooperates to align, in particular center, the coil spring on the spring assembly.

Methodology Applied
Scientific EffectGeometric constraint:

Implementation Method 2

The spring assembly comprises two support elements (12) and three coil springs (14). The coil springs (14) each have different lengths, diameters, and wire diameters.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

The spring assembly is pre-tensioned and arranged in spring windows of a torsion damper

Methodology Applied
Scientific EffectTorsion damping: Damping

Implementation Method 4

The intermediate surfaces are arranged between the individual steps and generating the axial offset of the steps. The coil springs can therefore move laterally relative to the support element to a limited extent during operation, which increases the friction of the spring assembly and the wear of the spring assembly.

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP3026293B2Spring package
Publication Date: 2024.10.09 ZF FRIEDRICHSHAFEN AG
  • EP3026293B2 patent drawingFigure 1~2
  • EP3026293B2 patent drawingFigure 3
  • EP3026293B2 patent drawingFigure 4

AI summary

Spring assembly (10) for a torsional damper (40) of a clutch disc (38), comprising a coil spring (14), a support element (12) on which a disc section (18) and a step section (20) are formed, wherein a step (24) for actuating the coil spring (14) is formed on the step section (20) and wherein a control surface (28) of the coil spring (14) is assigned to a contact surface (26) of the step (24) of the support element (12), wherein a first centering surface (34) is formed on the step (24) of the step section (20), which corresponds to a second centering surface (36) of the coil spring (14) for centering the coil spring (14).