Cellular Polyurethane Elastomer Springs for Heavy Load Suspension
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Solution Overview
Problem
Existing vehicular suspension systems, particularly for heavy-loaded vehicles or those traveling on rough roads, face issues with load distribution, ride comfort, and durability due to limitations in spring length and material properties, leading to premature failure and discomfort.
Innovation Solution
A bolt-on suspension enhancer using a cellular polyurethane elastomeric spring body capable of 70% compression and 130% extension, designed with specific mounting means for each vehicle make and model, providing improved load support and damping, and featuring a casted cylindrical shape with end plates and convolutions for structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If leaf spring-packs are lengthened to improve ride comfort, then ride quality is enhanced, but load support capability decreases and lateral twisting increases
Solution Approach 1:
The patent employs a composite structure combining a shorter leaf spring-pack with a cellular polyurethane elastomeric enhancer. The polyurethane material provides superior load support and damping properties, compensating for the reduced length of the spring-pack while maintaining ride comfort. This composite approach allows the system to achieve both comfort and strength that neither component could provide alone.
Solution Approach 2:
The invention changes the material parameters by introducing cellular polyurethane elastomer with specific durometer ratings (60-90 Shore A) and cellular structure characteristics. This material parameter change enables the enhancer to provide progressive spring characteristics and high damping capacity, resolving the contradiction between spring length and load support capability.
2Ease of operation
If leaf spring-packs are lengthened to improve ride comfort, then ride quality is enhanced, but lateral twisting susceptibility increases
Solution Approach 1:
The cellular polyurethane elastomeric enhancer serves as a composite element that resists lateral twisting through its cellular structure and material properties. When installed alongside the shortened spring-pack, it provides lateral stability while the spring-pack maintains ride comfort, thus resolving the contradiction between comfort and lateral stability.
Solution Approach 2:
The enhancer is positioned at specific locations (front and rear axles) where lateral twisting forces are most critical. The mounting brackets and enhancer configuration provide localized lateral support without affecting the overall ride comfort characteristics of the suspension system.
3Strength
If high durometer rubber is used for suspension enhancement, then load support is improved, but engagement becomes harsh
Solution Approach 1:
The patent utilizes the progressive spring characteristics of cellular polyurethane elastomer to create a non-linear force-deflection relationship. At low deflections, the material provides softer engagement, while at high deflections under heavy load, it delivers increased support. This parameter variation with deformation resolves the contradiction between load support and engagement smoothness.
Solution Approach 2:
The cellular structure of the polyurethane elastomer provides progressive spring characteristics through its porous architecture. The cellular walls collapse progressively under load, providing initial softness for smooth engagement and increasing stiffness for heavy load support, thus resolving the contradiction between these two requirements.
4Ease of operation
If air bag systems are used for suspension enhancement, then ride comfort is improved, but system reliability decreases due to leakage and rupture risk
Solution Approach 1:
The cellular polyurethane elastomeric enhancer is designed as a maintenance-free, non-depleting component that does not rely on pressurized gas. Unlike air bags that can leak or rupture, the polyurethane enhancer maintains its structural integrity and performance characteristics throughout its service life, significantly improving system reliability while maintaining ride comfort.
Solution Approach 2:
The enhancer is designed to be self-contained and maintenance-free, requiring no external air supply, pressure regulation, or periodic inflation/deflation cycles. The cellular polyurethane material inherently maintains its damping and spring properties without external intervention, eliminating the reliability issues associated with air bag systems.
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 enhances load support and ride comfort by maximizing damping and durability, resisting spike loading and maintaining performance across varying conditions, including heavy loads and off-road use, with minimal maintenance and resistance to water absorption and temperature changes.
Implementation Method 1
a casted resilient cellular polyurethane elastomeric spring body capable of being repeatedly compressed 70% and repeatedly stretched to 130% of its unstressed length
Implementation Method 2
providing a smoother and more comfortable ride... the frequency increasing with increased velocity of the vehicle. This oscillation is facilitated by the vehicle's suspension system
Data Source
AI summary
A vehicular suspension enhancement that comprises the addition of a pair of cellular polyurethane elastomer cylindrical shaped springs, one located on each side of an axle. Each spring is operatively attached between the axle and the vehicular frame and made from a cast of cellular polyurethane elastomer derived from a polyol diisocyanate mixture containing naphthalene-1,5-diisocyanate (NDI)-terminated prepolymer and a polyol selected from the group consisting of polyether polyol, polyester polyol, or a combination thereof.