EPDM Sound Insulation Sheet With Mica-Dolomite Noise Damping

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Solution Overview

Problem

Existing sound insulation materials for electric vehicles, such as those using PVC or EVA resins with single flake fillers, fail to effectively reduce low-frequency and high-frequency noise, necessitating improved noise reduction solutions.

Innovation Solution

A sound insulation composition combining flake-shaped mica powders and block-shaped dolomite with EPDM rubber, which generates relative strains and pores, enhancing energy consumption and sound absorption, and is mixed with vulcanizing agents, compatibilizers, and fire retardants to improve damping capacity and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If PVC or EVA resins with single flake fillers are used as sound insulation materials, then the materials can be easily manufactured, but they cannot effectively reduce low-frequency and high-frequency noise

Engineering Contradiction:
Improveease of manufactureVSAvoidsound insulation effect
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a composite material system consisting of EPDM rubber matrix combined with two types of fillers (flake-shaped mica and block-shaped dolomite) with different shapes and elastic moduli. This composite structure creates multiple deformation mechanisms that effectively reduce both low-frequency and high-frequency noise, resolving the contradiction between ease of manufacture and sound insulation effectiveness.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by using fillers with different shapes (flake-shaped mica and block-shaped dolomite) and different elastic moduli distributed within the EPDM rubber matrix. Each filler type contributes differently to sound insulation at various frequency ranges, with the flake-shaped fillers providing barrier effects and block-shaped fillers providing damping effects, thereby achieving comprehensive noise reduction across different frequencies.

Inventive Principle:
Principle #3Local quality

2Reliability

If flake-shaped mica powders and block-shaped dolomite are added to EPDM rubber, then sound absorption and sound insulation effects are improved, but the device complexity increases

Engineering Contradiction:
Improvesound insulation effectVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges two different filler types (flake-shaped mica and block-shaped dolomite) into a single composite system with EPDM rubber. This combination creates synergistic effects where the different shapes and elastic moduli of the fillers work together to reduce sound transmission through multiple mechanisms (barrier effect, damping effect, and energy dissipation), improving sound insulation without requiring separate treatment for different frequency ranges.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the physical parameters of the sound insulation material by selecting fillers with specific shape characteristics (flake-shaped vs. block-shaped) and different elastic moduli. These parameter changes enable the material to respond differently to various frequency ranges of sound waves, with the flake-shaped fillers providing resistance to sound wave propagation and the block-shaped fillers providing vibration damping, thereby achieving broad-spectrum noise reduction.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple fillers with different elastic moduli are used to generate relative strains, then additional energy consumption is generated improving sound insulation, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvesound insulation effectVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes mechanical vibration principles by incorporating fillers with different elastic moduli that generate relative strains when subjected to sound wave-induced vibrations. The flake-shaped mica and block-shaped dolomite particles deform differently under stress, creating internal friction and energy dissipation that converts sound energy into heat, thereby reducing sound transmission. This passive vibration-based mechanism improves sound insulation without adding active control systems.

Inventive Principle:
Principle #18Mechanical vibration

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 resulting sound insulation sheet demonstrates superior sound insulation, vibration absorption, freeze resistance, and fire resistance, with improved mechanical strength and acoustic performance across various frequency bands.

Implementation Method 1

since the flake-shaped mica powders and block-shaped dolomite have different elastic modulus from the EPDM rubber, so that different strains are generated in these components, thus generating relative strains when they constitute the sound insulation composition, therefore additional energy consumption in the sound insulation composition may be generated

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

because of presence of the flake-shaped mica powders and block-shaped dolomite, there is a plurality of pores inside the sound insulation composition, and the presence of these pores may improve sound absorption and sound insulation effects of the sound insulation composition

Methodology Applied
Scientific EffectPorosity: Porosity

Implementation Method 3

the EPDM rubber has a good damping capacity, and it may be mixed with the flake-shaped mica powders and block-shaped dolomite, so as to further improve a damping capacity, an effect of sound insulation

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP3394172B1Sound insulation composition and sound insulation sheet for vehicle
Publication Date: 2023.08.30 BYD CO LTD

AI summary

A sound insulation composition and a sound insulation sheet for a vehicle are provided. The sound insulation composition includes 50 to 300 parts by weight of EPDM rubber, 10 to 300 parts by weight of mica powers, 10 to 300 parts by weight of dolomite, 2 to 15 parts by weight of a vulcanized agent, 3 to 60 parts by weight of a compatilizer, 30 to 300 parts by weight of a fire retardant, 0.2 to 3 parts by weight of a cross-linking agent, 10 to 80 parts by weight of a plasticizer, and 100 to 500 parts by weight of barium sulfate. The sound insulation sheet for the vehicle is made of the sound insulation composition mentioned above.