Copolyetherester Jounce Bumper Energy Absorption

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Solution Overview

Problem

Conventional jounce bumpers, particularly those made of foamed polyurethane and vulcanized rubber, face challenges in durability, resistance to automotive fluids, and precise energy absorption due to limitations in material properties and manufacturing techniques, leading to suboptimal performance in absorbing jounce forces and maintaining ride comfort.

Innovation Solution

A jounce bumper design featuring a hollow elongated tubular body with specific fillet radii and wall thickness ratios in its bellows, made of copolyetherester, which enhances energy absorption by optimizing the ratio of maximum wall thickness to intermediate wall thickness, allowing for superior force-displacement behavior and increased energy absorption capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If foamed polyurethane is used for jounce bumpers, then good ride characteristics are achieved, but production cost increases due to energy- and time-consuming crosslinking process

Engineering Contradiction:
Improveride characteristicsVSAvoidproduction cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter from crosslinked foamed polyurethane to thermoplastic copolymer, eliminating the crosslinking process while maintaining ride characteristics through the elastic properties of the thermoplastic material

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the chemical crosslinking process with a mechanical thermoplastic forming process, substituting chemical bonding with physical melting and cooling to achieve the desired material properties

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If conventional blow molding is used, then manufacturing cost is reduced, but dimensional precision and wall thickness uniformity deteriorate

Engineering Contradiction:
Improvemanufacturing costVSAvoiddimensional precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses a multi-stage blow molding process with dynamic control of inflation pressure and timing, allowing the parison to be formed and then precisely expanded to achieve both cost-effectiveness and dimensional precision

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the blow molding process into distinct stages: parison formation, initial inflation, and final expansion, with each stage optimized for specific dimensional requirements

Inventive Principle:
Principle #1Segmentation

3Strength

If wall thickness is increased to improve energy absorption, then energy absorption capacity increases, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveenergy absorption capacityVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies different wall thicknesses at different locations of the jounce bumper, with thicker walls at the ends for maximum energy absorption and thinner walls in intermediate sections, optimizing both performance and manufacturability

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

The copolyetherester jounce bumper design achieves superior energy absorption, with higher force levels at 50% relative deformation and high deformation at 10kN, demonstrating improved durability and ride comfort by maximizing energy absorption and displacement under applied forces.

Implementation Method 1

Jounce bumpers are elongated, generally cylindrical or conical, members with or without convolutes, made of a compressible and elastomeric material that extends around the piston rod

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The copolyetherester jounce bumper design achieves superior energy absorption, with higher force levels at 50% relative deformation and high deformation at 10kN

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 3

Jounce bumpers function by a progressive stacking of the convolutions to provide resistance to jounce forces

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

the tubular body having at least two bellows, each bellow being defined by a peak and a trough

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP2603714B1Thermoplastic jounce bumpers
Publication Date: 2018.02.14 EI DU PONT DE NEMOURS & CO
  • EP2603714B1 patent drawingFigure 1
  • EP2603714B1 patent drawingFigure 2A~2B
  • EP2603714B1 patent drawingFigure 3

AI summary

The invention provides vehicle suspension systems, and more particularly jounce bumpers made of elastomeric thermoplastic material, having improved design to maximize energy absorption.