Multi-Layer Tire Foam Structure for Cavity Noise Durability
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Solution Overview
Problem
Conventional noise-dampening foam materials in tires face durability issues due to internal strains from flexing and bending, and filling tires completely with foam is expensive and affects cooling properties, while electric vehicles highlight the need for advanced noise reduction technologies.
Innovation Solution
A pneumatic tire design featuring multiple layers of open cell noise-dampening foam strips attached to the innerliner, with each layer having a specific axial width and radial thickness, providing improved noise attenuation and flexibility, and allowing for adaptable and cost-effective noise reduction across different tire sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a single thick layer of foam material is applied to dampen tire cavity noise, then noise attenuation is improved, but internal strains from flexing and bending cause fatigue cracks and limited durability
Solution Approach 1:
The patent divides the foam noise dampening material into multiple thin layers (typically 2-5 layers) instead of using a single thick layer. Each layer has a thickness of 2-10mm, and they are arranged radially from the innerliner outward. This segmentation reduces internal strains and flexing stresses within each individual layer, preventing fatigue cracks while maintaining effective noise attenuation through the combined thickness of all layers.
2Object-generated harmful factors
If the tire cavity is almost completely filled with foam material to maximize noise dampening, then noise attenuation is improved, but manufacturing cost increases and cooling properties are negatively affected
Solution Approach 1:
The patent applies foam material partially to the tire cavity rather than filling it completely. The foam layers are positioned radially below the tread portion and extend circumferentially over at least 50% of the tire's inner circumference, with the radially outer surface of the outermost layer positioned at 10-50mm from the tread portion. This partial application provides effective noise dampening in the critical noise-generating regions while preserving cooling channels and reducing material costs.
3Object-generated harmful factors
If thick foam layers are used to dampen noise, then noise attenuation is improved, but the foam material creates internal strains due to flexing and bending
Solution Approach 1:
The patent segments the foam structure into multiple thin radial layers, where each layer experiences reduced flexing and bending stresses compared to a single thick layer. The thin layers (2-10mm each) can flex more easily with tire deformation, reducing internal strain accumulation and preventing fatigue failure while collectively providing the necessary noise dampening thickness.
4Object-generated harmful factors
If complete foam filling is used to achieve maximum noise reduction, then noise attenuation is improved, but the tire becomes less adaptable to different tire sizes and applications
Solution Approach 1:
The patent uses multiple modular foam layers that can be independently sized and positioned, allowing the same basic multi-layer structure to be adapted to different tire sizes and applications. Each layer can be customized in thickness, axial width, and circumferential extent, providing flexibility to optimize noise dampening for various tire dimensions without requiring complete cavity filling.
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 multi-layered foam strip design enhances durability, reduces noise and vibration, and maintains effective thermal conduction, while being cost-effective and adaptable to various tire sizes, addressing the limitations of single-layer foam solutions and ensuring reduced noise levels in electric vehicles.
Implementation Method 1
multiple layers of open cell noise dampening foam strip (material) attached on top of each other to the innerliner within the tire cavity... The open cell dampening material is much more suitable for dampening noise and/or vibration than closed cell foam material. In particular, an acoustic attenuation of tire cavity resonance is supported by the noise damping features of the present invention.
Implementation Method 2
The open cell dampening material is much more suitable for dampening noise and/or vibration than closed cell foam material... maintains effective thermal conduction
Data Source
AI summary
In a first aspect of the invention, a pneumatic tire is provided, the pneumatic tire comprising two spaced apart beads, a tread portion, a pair of sidewalls extending radially inward from axially outer edges of the tread portion to join the respective beads, the axially outer edges of the tread portion defining a tread width, a carcass, an innerliner covering the carcass and enclosing a tire cavity when mounted on a rim, and multiple layers of open cell, noise damping foam strip material attached on top of each other to the innerliner within the tire cavity in an area radially below the tread portion, wherein each layer has an axial width from 20% to 80% of the tread width and a radial thickness from 5% to 20% of the tread width and said multiple layers fill together from 8% to 40% of the volume of the tire cavity.