Serviceable muffler

A serviceable muffler (20) has an end plate (34) releasably clamped (36) to an open end (30) of a muffler body (26) and permitting access to an internal catalytic or filter element (28) for removal and replacement. An apertured flange (44) has an outer border with flared rounded portion (46) complemental to flared rounded portions (40 and 42) of each of the end plate (34) and the open end (30) of the body (26), and having an inner border defined by an aperture (48) through which the element (28) is removed and replaced. Servicing and manufacturing methods are provided.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to mufflers, and more particularly to serviceable mufflers containing an element requiring servicing.

Emission regulations for internal combustion engines are requiring ever decreasing levels of emissions. It has accordingly become necessary to fit catalysts and filters inside of mufflers to treat engine exhaust. Particle filters for diesel engines require routine cleaning to remove ash built-up from the filters. Catalytic elements also require maintenance and/or replacement.

The present invention provides a serviceable muffler permitting easy removal of an end plate from an open end of a muffler body for gaining access to an internal filter element and/or catalytic element. The invention eliminates the need for welding, and the need for a sealing gasket. The invention further provides particularly cost effective manufacturability. The invention uses high speed lock forming techniques providing precise mounting and sealing structure.

DETAILED DESCRIPTION

FIG. 1shows a serviceable muffler20with inlet22, outlet24, and having a muffler body26containing an internal element28requiring servicing, for example a particulate filter element and/or a catalytic element. The body has an open end30,FIGS. 1,2, allowing access to element28for removal and replacement of element28through open end30, e.g. rightward removal as shown at arrow32inFIG. 2. An end plate34closes body26at open end30. Preferably, both of open end30and end plate34have a flared rounded portion, to be described. A clamp36releasably clamps end plate34to open end30to close body26, and is releasable to permit removal of end plate34,FIG. 2, from open end30of body26for gaining access to element28. Clamp36is preferably tightened by a threaded bolt38along its circumference, and released by untightening such bolt, as is known. Body26is closed by end plate34without welding. Body26is closed by end plate34and sealed thereto at open end30without the need for a gasket.

Each of end plate34and open end30of body26has a flared rounded portion40and42, respectively,FIGS. 3,10. An apertured flange44has an outer border with a flared rounded portion46complemental to the flared rounded portions40and42of each of end plate34and open end30of body26. Apertured flange44has an inner border defined by an aperture48therethrough. Element28is removed and replaced through aperture48.

Open end30of body26has a first section60,FIGS. 9,10, extending axially along the noted first axial direction (rightwardly inFIGS. 9,10) to flared rounded portion42of open end30of body26, and has a second section62extending axially along the noted second axial direction (leftwardly inFIGS. 9,10) from flared rounded portion42of open end30of body26. Second section62has a terminating end64spaced laterally outwardly of first section60by a pocket66of given lateral width. Flared rounded portion46of apertured flange44is a first rounded portion of the apertured flange. Apertured flange44has a second rounded portion68. Apertured flange44has a first section70extending axially along the noted first axial direction (rightwardly inFIGS. 9,10) to the first rounded portion46of apertured flange44, and has a second section72extending axially along the noted second axial direction (leftwardly inFIGS. 9,10) from first rounded portion46of apertured flange44to second rounded portion68of apertured flange44, and has a third section74extending axially along the noted first axial direction (rightwardly inFIGS. 9,10) from second rounded portion68of apertured flange44. Third section74of apertured flange44extends axially rightwardly into pocket66.

Second rounded portion68of apertured flange44has a first arcuate surface76,FIGS. 9,10, facing axially in the noted first axial direction (rightwardly inFIGS. 9,10) toward terminating end64of second section62of open end30of body26. Second rounded portion68of apertured flange44has a second arcuate surface78facing axially in the noted second axial direction (leftwardly inFIGS. 9,10) and engaged by clamp36. Rounded portion40of end plate34has a first arcuate surface80facing axially in the noted first axial direction (rightwardly inFIG. 10), and has a second arcuate surface82facing axially in the noted second axial direction (leftwardly inFIG. 10). Second arcuate surface82of rounded portion40of end plate34engages first arcuate surface56of first rounded portion46of apertured flange44. First arcuate surface80of rounded portion40of end plate34is engaged by clamp36. Clamp36has first and second engagement surfaces84and86. Engagement surface84faces axially in the noted first axial direction (rightwardly inFIG. 10) and engages second arcuate surface78of second rounded portion68of apertured flange44. Second engagement surface86of the clamp faces axially in the noted second axial direction (leftwardly inFIG. 10) and engages first arcuate surface80of rounded portion40of end plate34.

Apertured flange44is curled around open end30of body26in an interference lock-fit permanently mounted to body26such that apertured flange44remains on body26upon removal of end plate34. Flared rounded portion42of open end30of body26has a convex curvature facing in the noted first axial direction (rightwardly inFIG. 10) away from second axial end54of body26. Flared rounded portion46of apertured flange44is the noted first rounded portion of apertured flange44. Apertured flange44has the noted second rounded portion68. First rounded portion46of apertured flange44has a convex curvature facing in the noted first axial direction (rightwardly inFIG. 10). Second rounded portion68of apertured flange44has a convex curvature facing in the noted second axial direction (leftwardly inFIG. 10) toward second axial end54of body26. The noted first and second rounded portions46and68of apertured flange44are axially spaced from each other and engage the open end of body26at axially spaced engagement points46and68, with body section62trapped therebetween, preventing axial movement of apertured flange44along body26.

The present invention provides a method for servicing muffler20. Clamp36is released by untightening threaded bolt38to permit removal of end plate34from open end30of body26for gaining access to element28. Element28is removed axially rightwardly as shown at arrow32inFIG. 2through aperture48,FIG. 3, of apertured flange44, while apertured flange44remains mounted to open end30of body26.

FIGS. 4–9illustrate a preferred manufacturing method for making serviceable muffler20. InFIG. 4, apertured flange44is inserted into body26, e.g. by moving body26axially rightwardly as shown at arrow90onto apertured flange44, or vice versa, with axially extending sidewall92of body26in abutting relation with axially extending sidewall94of apertured flange44,FIG. 5. In the preferred embodiment, sidewall92of body26has a pre-flared laterally extending portion96at a first end98, and sidewall94of apertured flange44has a pre-flared laterally extending portion100at a first end102. Upon the noted insertion90, sidewall portion96flattens against sidewall portion100. First end102of sidewall94of apertured flange44extends laterally beyond first end98of sidewall92of body26. First end102of sidewall94of apertured flange44is engaged with a first mandrel104,FIG. 6, having a curved engagement surface106. Mandrel104is moved laterally inwardly, which is downwardly inFIGS. 6 and 7as shown at arrow108, toward body26, while the latter is turning about its centerline along axis50, as illustrated at109, to further flare and curl the sidewall of apertured flange44at portion100around first end98of the sidewall of body26,FIG. 7. Mandrel104continues to move downwardly,FIG. 8, to move the mandrel laterally inwardly toward body26to further flare and curl both of the noted sidewalls92and94at respective portions96and100around open end30of the body.

Upon completion of the noted movement of mandrel104at108inFIG. 8, the noted first end98of portion96of sidewall92of body26is spaced laterally outwardly of first end102of portion100of sidewall94of apertured flange44by a lateral gap110therebetween,FIG. 8. A second mandrel112,FIG. 9, which may be a different mandrel than mandrel104or maybe a different surface of mandrel104, is then moved laterally inwardly toward body26, which is downwardly as shown at arrow114inFIG. 9, to engage the noted curled and flared sidewall of apertured flange44at portion100, while body26is turning about its centerline along axis50, as illustrated at109, to close lateral gap110ofFIG. 8and move first end98of portion96of sidewall92of body26laterally inwardly into engagement with first end102of portion100of sidewall94of apertured flange44. The resulting structure is that shown inFIG. 9, wherein, as above noted, the open end of the body has a first section60,FIGS. 9,10, extending axially along the noted first axial direction (rightwardly inFIGS. 9,10) to the flared rounded portion42of open end30of body26, and has a second section62extending axially along the noted second axial direction (leftwardly inFIGS. 9,10) from flared rounded portion42of open end30of body26, with second section62having a terminating end64spaced laterally outwardly of first section60by pocket66of given lateral width after closing of gap110, and wherein flared rounded portion46of apertured flange44is a first rounded portion of the apertured flange, and wherein the apertured flange has a second rounded portion68, and wherein apertured flange44has the noted first section70extending axially along the noted first axial direction (rightwardly inFIGS. 9,10) to first rounded portion46of apertured flange44, and has the noted second section72extending axially along the noted second axial direction (leftwardly inFIGS. 9,10) from first rounded portion46of apertured flange44to second rounded portion68of apertured flange44, and has the noted third section74extending axially along the noted first axial direction (rightwardly inFIGS. 9,10) from second rounded portion68of apertured flange44, and wherein third section74extends axially rightwardly into pocket66.

Section72of the sidewall of apertured flange44is laterally outward of and in engagement with section62of the sidewall of body26. Section62of the sidewall of body26is laterally outward of and in engagement with section74of the sidewall of apertured flange44. Section74of the sidewall of apertured flange44is laterally outward of and in engagement with section60of the sidewall of body26. Section60of the sidewall of body26is laterally outward of and in engagement with section70of the sidewall of apertured flange44.

In the preferred method, apertured flange44is inserted into body26,FIGS. 4,5, such that the sidewall of the apertured flange extends beyond the noted first end98of the sidewall of body26such that the noted first end102of the sidewall of the apertured flange is spaced from the first end98of the sidewall of the body. The sidewall of the apertured flange is then flared and curled around the first end98of the sidewall of the body, and both sidewalls96,100are flared and curled around the open end of the body. In the preferred manufacturing method, the sidewalls of the apertured flange and the body are pre-flared as shown inFIG. 4at96and100.

It is recognized that various equivalents, alternatives and modifications are possible within the scope of the appended claims.