Vehicle Muffler Sound-Absorbing Material Installation Method

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Solution Overview

Problem

Conventional methods for installing sound-absorbing materials in vehicle mufflers require large-scale equipment and are time-consuming, increasing manufacturing line takt time.

Innovation Solution

A method involving the use of nonwoven fabric made from inorganic fibers like basalt or glass, which is loosely knitted and subjected to needle processing, allowing for efficient sound absorption and strength maintenance, and is installed between the inner and outer pipes of a double pipe muffler without the need for large equipment, using a tubular body formed by attaching half bodies to the pipes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If glass fiber is blown into the space between inner and outer pipes using a nozzle with compressed air and a fan, then the sound-absorbing material can be installed, but large-scale equipment and piping are required

Engineering Contradiction:
Improveinstallation processVSAvoidequipment scale
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention extracts the sound-absorbing material installation from the complex blowing system (nozzle, fan, piping) and replaces it with a simple insertion method using a pre-formed tubular body, eliminating the need for large-scale equipment

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sound-absorbing material is pre-formed into a tubular body with half-bodies attached to the inner pipe outer surface before installation, allowing direct insertion without requiring blowing equipment during the installation process

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If glass fiber is blown into the space between inner and outer pipes using a nozzle with compressed air and a fan, then the sound-absorbing material can be installed, but a long time is required from start to completion

Engineering Contradiction:
Improveinstallation processVSAvoidtakt time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The sound-absorbing material is pre-assembled into a tubular body structure with half-bodies attached to the inner pipe before the installation process, which significantly reduces the installation time compared to blowing fiber material in place

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sound-absorbing material is divided into half-bodies that are attached to the inner pipe, allowing for easier handling and faster installation as a pre-assembled unit

Inventive Principle:
Principle #1Segmentation

3Reliability

If inorganic fiber in filament form is used, then high back pressure of exhaust gas can be endured, but the material must maintain strength at high temperatures

Engineering Contradiction:
Improveback pressure resistanceVSAvoidhigh-temperature strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention uses inorganic fibers (basalt or glass) in filament form that combine high back pressure resistance with high-temperature strength, creating a composite structure that withstands both mechanical and thermal stresses in the exhaust environment

Inventive Principle:
Principle #40Composite materials

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

This method simplifies and accelerates the installation of sound-absorbing materials, reducing manufacturing line takt time and enabling the muffler to withstand high-temperature exhaust gases.

Implementation Method 1

sound absorption is efficiently performed due to small spaces formed by the opened strands

Methodology Applied
Scientific EffectSound absorption: Acoustic Absorption

Implementation Method 2

heating while infiltrating the binder resin into the entire outer periphery and the inside of the nonwoven fabric

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

allowing to stand for a predetermined period to solidify

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 4

inserting the tubular body into a space between an inner pipe and an outer pipe

Methodology Applied
Scientific EffectSuction: Suction

Implementation Method 5

blowing of the fiber, which disadvantageously increases a takt time of a manufacturing line

Methodology Applied
Scientific EffectCompressed air flow: Jet

Data Source

PatentEP4056816B1Vehicle muffler manufacturing method
Publication Date: 2024.10.30 NAKAGAWA SANGYO
  • EP4056816B1 patent drawingFigure 1~2
  • EP4056816B1 patent drawingFigure 3~4
  • EP4056816B1 patent drawingFigure 5~6

AI summary

To provide a vehicle muffler manufacturing method that can simply and promptly install a sound-absorbing material between pipes of an inner-outer double pipe of the vehicle muffler. The vehicle muffler manufacturing method includes: forming a tubular body 6 with a nonwoven fabric 2 made of inorganic fibers 11 each being in a filament form; inserting and installing the tubular body 6 as a sound-absorbing material into a space S between an inner pipe 72 and an outer pipe 71 of an inner-outer double pipe constituting a vehicle muffler. The tubular body 6 is obtained by applying a binder 3 to one surface 2a of the nonwoven fabric 2, then rolling up the nonwoven fabric 2 into a tubular shape with the surface 2a applied with the binder 3 facing inward, infiltrating the binder 3 into the nonwoven fabric 2 rolled up into the tubular shape, and heating the nonwoven fabric 2 infiltrated with the binder 3 to a predetermined temperature.