Plastic Tubular Spring for Vehicle Headrest Noise

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Solution Overview

Problem

Metallic springs used in vehicle headrests oscillate and generate unwanted noise due to vibrations, particularly when driving on uneven ground.

Innovation Solution

A plastic spring formed into a tubular structure with a hollow cylinder design, featuring a ring structure and multiple filaments arranged in layers, which absorbs vibrations without generating noise when deformed or subjected to physical shocks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If metal springs are used in vehicle headrests, then the spring provides necessary elastic restoring force, but the spring oscillates and generates unwanted noise due to vibrations

Engineering Contradiction:
Improveelastic restoring forceVSAvoidunwanted noise
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The patent changes the material parameter from metal to plastic, fundamentally altering the damping characteristics of the spring. Plastic material inherently provides vibration damping, eliminating the oscillation and noise issues while maintaining the necessary elastic restoring force for headrest operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The spring is constructed as a composite structure with multiple filaments arranged in layers, combining plastic material properties to achieve both the required mechanical force and vibration suppression. The multi-layered filament construction provides enhanced damping characteristics compared to solid metal springs

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If plastic spring is used, then unwanted noise and vibrations are suppressed, but the spring must maintain sufficient strength and elasticity for headrest operation

Engineering Contradiction:
Improvenoise and vibrationsVSAvoidspring strength
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The spring uses a composite construction with multiple filaments arranged in layers, where the collective structure provides sufficient strength while individual plastic filaments provide vibration damping. This composite approach allows the spring to meet both strength requirements and noise suppression goals

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The spring is divided into multiple separate filaments rather than being a solid structure. This segmentation allows each filament to flex independently, providing both the necessary elastic strength and inherent vibration damping that eliminates noise while maintaining structural integrity

Inventive Principle:
Principle #1Segmentation

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 plastic spring effectively suppresses unwanted noise and vibrations, providing a quiet operation in vehicle headrest mechanisms.

Implementation Method 1

The plastic spring effectively suppresses unwanted noise and vibrations

Methodology Applied
Scientific EffectVibration absorption: Damping

Implementation Method 2

the spring is made entirely of plastic... When the force on the spring decreases, the first end area and the second end area move back into their original relative position, with the spring relaxing

Methodology Applied
Scientific EffectElastic restoration: Elasticity

Data Source

PatentEP3324070B1Spring, use of a plastic hose as a spring and fitting part for the interior of a vehicle
Publication Date: 2020.03.04 GRAMMER AG
  • EP3324070B1 patent drawingFigure 1~3
  • EP3324070B1 patent drawingFigure 4
  • EP3324070B1 patent drawingFigure 5

AI summary

The invention relates to a spring (36), in particular for moving at least a part of a vehicle interior fitting. The object of the invention was to create a spring in which disturbing noises due to vibrations do not occur. This object was achieved by making the spring from plastic.