Polyurethane Foam Tire Inner Wall Noise Reduction
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Solution Overview
Problem
Existing pneumatic tires fail to effectively reduce noise emissions, particularly cavity noise, while also being either heavy or complex and expensive to process, using polyurethane foams.
Innovation Solution
A polyurethane foam formulation based on diphenylmethane diisocyanate (MDI) and a polyol with greater than 50% ethylene oxide content is used to create a lightweight, efficient noise-absorbing foam that is easy to process and apply to the tire's inner wall, reducing cavity noise without increasing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional polyurethane foams are used to reduce noise, then noise reduction is achieved, but the foam becomes heavy and complex to process
Solution Approach 1:
The patent changes the chemical parameters of the polyurethane foam by using a polyol with greater than 50% ethylene oxide content. This parameter change results in a foam with different density and acoustic properties that achieves noise reduction while being lighter and easier to process than conventional foams.
Solution Approach 2:
The patent creates a composite polyurethane foam system combining MDI diisocyanate with a specific polyol containing high ethylene oxide content. This composite material formulation achieves superior noise reduction performance while reducing weight and improving processability compared to conventional single-component foams.
2Object-affected harmful factors
If conventional polyurethane foams are used to reduce noise, then noise reduction is achieved, but the processing becomes complex and expensive
Solution Approach 1:
The patent modifies the chemical composition parameters by specifying a polyol with greater than 50% ethylene oxide content, which fundamentally changes the foam's processing characteristics. This parameter change simplifies manufacturing operations and reduces production costs while maintaining effective noise reduction.
Solution Approach 2:
The patent utilizes the porous structure of the polyurethane foam, where the specific polyol formulation creates an optimized pore structure that enhances noise absorption. This porous material approach simplifies processing while achieving superior acoustic performance compared to dense conventional foams.
3Weight of moving object
If existing polyurethane foams are used, then some noise reduction is achieved, but they cannot simultaneously be light and efficiently absorb noise
Solution Approach 1:
The patent achieves the dual goal of light weight and high noise absorption efficiency by changing the polyol composition to contain greater than 50% ethylene oxide. This parameter change optimizes the foam's cellular structure and density to simultaneously reduce weight and enhance acoustic absorption in the critical 180-230 Hz frequency range.
Solution Approach 2:
The patent employs a porous polyurethane foam structure created through the specific polyol formulation. The porous architecture provides high surface area for sound wave interaction, enabling efficient noise absorption at low densities, thus achieving both light weight and high acoustic performance.
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 foam significantly reduces cavity noise by 2.5 dB(A) in the frequency range of 180 to 230 Hz, outperforming conventional foams in noise reduction while maintaining tire performance and simplicity in manufacturing.
Implementation Method 1
the polyurethane is based on a diphenylmethane diisocyanate (abbreviated to MDI) and on a polyol having an ethylene oxide content of greater than 50% (% by weight)... the foam significantly reduces cavity noise by 2.5 dB(A) in the frequency range of 180 to 230 Hz
Data Source
AI summary
The inner wall of a pneumatic tyre, in the vulcanized state, is provided with a layer of polyurethane foam, characterized in that the polyurethane is based on a diphenylmethane diisocyanate (MDI), in particular 4,4′-diphenylmethane diisocyanate, and on a polyol having an ethylene oxide content of greater than 50% (% by weight). This specific polyurethane formulation makes it possible to obtain a light foam that efficiently absorbs noise; it has the advantages of being simple and inexpensive and of being easy to process by direct casting of the reactants in the pneumatic tyre of the invention.