Microcellular Foam Damping in Motor Vehicle Locks

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Solution Overview

Problem

Existing locking system components in motor vehicles face issues with mis-positioning and noise due to the elastic rebound of rubber buffers used in impact arrangements, which affect the mechanical stress and operational behavior.

Innovation Solution

The use of a microcellular, open-pored plastic foam, such as polyurethane foam, as a baffle arrangement in the impact arrangement to absorb and dissipate kinetic energy, reducing rebound and mechanical stress, and providing effective damping properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a rubber buffer is used as an impact device, then mechanical stress on components is reduced, but rebound and noise occur causing mispositioning

Engineering Contradiction:
Improvemechanical stressVSAvoidpositioning accuracy
Core Design Contradiction:
Stress or pressureVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter from rubber (elastic) to plastic foam (viscoelastic with controlled relaxation), fundamentally altering how the impact device handles kinetic energy. This material substitution transforms the rebound problem into a controlled relaxation process, eliminating positioning errors while maintaining stress reduction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs plastic foam as a composite material that combines the stress-absorbing properties of rubber with the non-rebound characteristics of viscoelastic materials. The foam's unique cellular structure provides both cushioning and controlled recovery, solving the contradiction between stress reduction and positioning accuracy.

Inventive Principle:
Principle #40Composite materials

2Stress or pressure

If a rubber buffer is used to absorb impact, then mechanical stress is reduced, but rebound causes noise effects

Engineering Contradiction:
Improvemechanical stressVSAvoidnoise
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the material's elastic properties by substituting rubber with plastic foam, which has viscoelastic characteristics that dissipate energy through internal friction rather than elastic rebound. This parameter change eliminates the primary source of noise while preserving the stress-absorbing function.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a plastic foam element is used, then rebound is avoided and positioning is improved, but relaxation time increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidrelaxation time
Core Design Contradiction:
Manufacturing precisionVSDuration of action of moving object

Solution Approach 1:

The patent optimizes the plastic foam's cellular structure and material composition to control relaxation time. By adjusting foam density, cell size, and polymer type, the relaxation process is tuned to be sufficiently slow to prevent rebound but not excessively slow to interfere with operational timing.

Inventive Principle:
Principle #35Parameter changes

4Length of moving object

If the plastic foam is made thin to reduce space, then damping properties are maintained, but structural integrity may be compromised

Engineering Contradiction:
Improvefoam thicknessVSAvoidstructural integrity
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The patent changes the cellular architecture parameters of the plastic foam, using optimized cell size, density, and wall thickness to maximize damping efficiency within minimal thickness. The viscoelastic properties are enhanced through material composition rather than increasing thickness, maintaining both compactness and structural integrity.

Inventive Principle:
Principle #35Parameter changes

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

The solution effectively reduces mechanical stress and noise by dissipating kinetic energy, allowing for precise positioning and minimizing material fatigue, while maintaining damping properties even when thin, thus enhancing the operational behavior of motor vehicle locks and auxiliary locking arrangements.

Implementation Method 1

the plastic foam element (5), which consists at least partially, and preferably entirely, of a microcellular, open-cell plastic foam... absorbs the movement impulse... reduces the mechanical stress on the components located behind the rubber buffer

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

the open-cell plastic foam can exhibit exceptionally good damping properties... allows a considerable portion of the moving component's kinetic energy to be dissipated within the plastic foam

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 3

the plastic foam relaxes back to its original state relatively slowly, depending on the design... the inherent elasticity of the plastic foam is used to fasten the plastic foam element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2746504B1Closure system component
Publication Date: 2019.11.06 BROSE SCHLIESSSYSTEME GMBH & CO KG
  • EP2746504B1 patent drawingFigure 1
  • EP2746504B1 patent drawingFigure 2
  • EP2746504B1 patent drawingFigure 3

AI summary

The invention relates to a locking system component for a locking system (1) associated with a locking element (2) of a motor vehicle, wherein an impact arrangement (3) is provided for receiving a movement impulse from a movement element (4). It is proposed that the impact arrangement (3) comprises a plastic foam element (5) which consists at least partially, preferably entirely, of a microcellular, open-pore plastic foam, in particular a polyurethane foam.