Muffler

Details Muffler Muffler

2003-01-27

2004-03-16

Lockett, Kimberly (Department: 2837)

Acoustics

Sound-modifying means

Muffler, fluid conducting type

Reexamination Certificate

active

06705429

ABSTRACT:

BACKGROUND OF INVENTION
1. Field of Invention
The present invention relates in general to mufflers and more particularly to mufflers of a type that is suitable for use with an internal combustion engine to muffle or silence exhaust noise produced by the engine.
2. Description of Related Art
Hitherto, various types of mufflers have been proposed and put into practical use particularly in the field of automotive internal combustion engines.
One of such mufflers is shown in Laid-open Japanese Patent Application (Tokkaihei) 9-125930. In
FIGS. 15 and 16
of the accompanying drawings, there is shown the muffler of the Laid-open Application.
FIG. 15
is a sectional view of the muffler and
FIG. 16
is a sectional view taken along the line “XVI—XVI” of FIG.
15
. As is seen from the drawings, the muffler comprises a semi-cylindrical outer case
301
having longitudinal ends
301
a
and
301
b
closed, and a regularly cylindrical inner case
302
installed in outer case
301
to extend longitudinally. As is seen from
FIG. 15
, inner case
302
has a gas inlet part “IN” and a gas outlet part “OUT” at longitudinal ends. Within inner case
302
, there are arranged front and rear inner sections
303
and
304
each having a cylindrical wall
302
a
with a plurality of small openings
303
a
and
304
a
. Between front and rear inner sections
303
and
304
, there is arranged an intermediate space section
306
that comprises a partition wall
305
formed with a plurality of small openings
306
a
. Within an annular space defined between outer and inner cases
301
and
302
, there are arranged front and rear outer sections
403
and
404
that are separated by an intermediate space section
308
that comprises a partition wall
307
formed with a plurality of small openings
308
a
. In operation, exhaust gas from an associated engine enters front inner section
303
through gas inlet part “IN”. One part of gas in front inner section
303
is led to rear inner section
304
through intermediate space section
306
and discharged to open air through gas outlet part “OUT”, while the remaining part of gas in front inner section
303
is led into front outer section
403
through small openings
303
a
, into rear outer section
404
through small openings
308
a
, into rear inner section
304
through small openings
304
a
and discharged to open air through gas outlet part “OUT”. During such flow in the muffler, acoustic energy or noise of the exhaust gas is reduced or damped due to expansion/resonance effect possessed by the gas flow passages.
While, Laid-open Japanese Patent Applications (Tokkaihei) 7-13573 and 7-175485 show a sound insulating structure that is used as an under cover of an engine room of a motor vehicle for blocking noises of exhaust system of the engine from being emitted to open air. That is, for blocking noises of exhaust system, the sound insulting structure employs an acoustically improved mechanism.
Laid-open Japanese Patent Application (Tokkaihei) 11-132024 shows a muffler that is produced by practically employing the acoustically improved mechanism of the above-mentioned publications 7-13573 and 7-175485.
SUMMARY OF INVENTION
However, due to inherent construction, the above-mentioned known mufflers have failed to provide users with a satisfaction. That is, some are poor in muffling performance, some are high in cost or some are difficult to assemble.
It is therefore an object of the present invention to provide a muffler that is high in muffling performance, low in cost and easy to assemble.
According to a first aspect of the present invention, there is provided a muffler which comprises a case having opposed ends closed; a partition structure installed in the case to constitute a sound silencing path; inlet and outlet pipes incorporated with the sound silencing path; and a sound shielding wall structure installed in the case to constitute a part of the sound silencing path, wherein the sound shielding wall structure comprises first and second partition plates; a positioning structure that puts the first and second partition plates together to keep a given distance therebetween; a first group of projections defined by the first partition plate and projected toward the second partition plate, each projection of the first group having a first opening formed therethrough; and a second group of projections defined by the second partition plate and projected toward the first partition plate, each projection of the second group having a second opening formed therethrough, the projections of the second group respectively facing the projections of the first group having a given clearance kept therebetween.
According to a second aspect of the present invention, there is provided a muffler which comprises a case having opposed ends closed; at least one partition plate installed in the case to divide an interior of the same into two chambers; a sound shielding wall structure installed in one of the two chambers to divide the same into first and second sound chambers allowing the other one of the two chambers to serve as a third sound chamber; and pipe members projected into the case passing through the partition plate and the sound shielding wall structure to define in the case a sound silencing path including the first, second and third sound chambers, wherein the sound shielding wall structure comprises first and second partition plates; a positioning structure that puts the first and second partition plates together to keep a given distance therebetween; a first group of projections defined by the first partition plate and projected toward the second partition plate, each projection of the first group having a first opening formed therethrough; and a second group of projections defined by the second partition plate and projected toward the first partition plate, each projection of the second group having a second opening formed therethrough, the projections of the second group respectively facing the projections of the first group having a given clearance kept therebetween.


REFERENCES:
patent: 4192402 (1980-03-01), Nakagawa et al.
patent: 4333544 (1982-06-01), Seeger
patent: 4700805 (1987-10-01), Tanaka et al.
patent: 5025890 (1991-06-01), Hisashige et al.
patent: 5614699 (1997-03-01), Yashiro et al.
patent: 5723827 (1998-03-01), Sasaki et al.
patent: 5823600 (1998-10-01), Iwao
patent: 0 863 054 (1998-09-01), None
patent: 0 869 037 (1998-10-01), None
patent: 0 889 459 (1999-01-01), None
patent: 7-13573 (1995-01-01), None
patent: 7-175485 (1995-07-01), None
patent: 8-314469 (1996-11-01), None
patent: 9-125930 (1997-05-01), None
patent: 11-132024 (1999-05-01), None

Affiliated with

Also associated with

Rating

Muffler does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Muffler, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Muffler will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3274377