JP2676262B2 - Exhaust muffler - Google Patents

Description

TECHNICAL FIELD The present invention relates to an exhaust muffler.

PRIOR ART Vehicle exhaust systems have one or more pipes for carrying exhaust gases from the engine. Each pipe extending from the engine leads to a catalytic converter that serves to convert certain offensive gases in the exhaust stream into non-offensive types. The exhaust pipe extends from the catalytic converter to the muffler, which acts to damp the noise associated with the exhaust gas flow. The tailpipe therefore extends from the muffler to where the exhaust gases on the vehicle are safely and conveniently released.

A typical prior art muffler has a plurality of separate tubes supported in parallel rows by a plurality of laterally extending baffles. Selected portions of each tube have holes, staggered windows, and openings through which exhaust gases moving through can be controlled and escaped. Each tube is typically rigidly connected to at least one baffle, and the rows of parallel tubes and lateral baffles assembled are of a generally tubular shell with a circular or oval cross-sectional shape corresponding to the shape of the baffle. You can slide it inside. A separate outer envelope is typically wrapped around the outer shell to mitigate noise associated with shell vibration. A pair of opposing end caps, or headers, are securely coupled to the longitudinal ends of the next opposing tubular shell and outer envelope to substantially enclose the muffler. Each end cap typically has at least one opening to allow communication with the interior of the muffler. The opening in the end cap is typically mated with one of the tubes inside the muffler. The assembly of elements in this representative prior art muffler forms a plurality of chambers. In particular, the chamber is formed between the tubular shell and either of a pair of spaced baffles, or between one baffle and one end cap of a prior art muffler. The relative distances of the baffles in the muffler, the dimensions of the tubes within them, the dimensions of the staggered windows, the openings, etc. are all chosen to provide a specific attenuation of the exhaust gas noise. In particular, the exhaust gas flowing through the device expands through the various holes, windows, openings, etc. into the corresponding chamber to achieve a certain noise attenuation.

When the exhaust muffler is considered for its original equipment, the muffler is typically welded to an elongated serpentine exhaust pipe and tail pipe. The muffler, exhaust pipe and tail pipe assembly is then sent to the original equipment vehicle manufacturer so that the completed exhaust system assembly can be mounted on the vehicle.

The prior art muffler and exhaust system elements described above adequately dampen noise associated with the exhaust gas flow. However, prior art exhaust mufflers require a large number of separate elements that must be assembled in a labor intensive manufacturing process. The resulting muffler tends to be unnecessarily heavy and there is little design choice associated with the shape of the muffler or the alignment of pipes to or from the muffler. These inherent limitations of the prior art mufflers make it extremely difficult to fit the exhaust system within the limited available space under the vehicle.

The prior art further has a muffler consisting of stamped forming elements. For example, U.S. Pat. No. 4,396,090 shows a muffler waiting for a pair of inner plates stamped to form a pair of opposing grooves. The inner plate has grooves matching each other,
It is assembled to form a tube therebetween. The inner plate is then placed in the conventional wrap-around outer shell described above to form a muffler. Separate inner baffles extend between the stamped plate and the wrap outer shell to form a chamber in the muffler of US Pat. No. 4,396,090.

The prior art further has a muffler consisting of only two opposing shells, which shells are stamped to form a spiral row of stamping tubes and stamping chambers. Mufflers of this type are shown in U.S. Pat. No. 2,484,827, U.S. Pat. No. 3,176,791, U.S. Pat. No. 3,638,756.

The prior art also has a muffler formed from four stamping elements. This type of muffler has a pair of inner plates stamped to form opposing grooves. The plates are mounted in face-to-face relationship with each other and the opposing grooves form a tube. The inner plate is further provided with a stamped hole, a staggered window, etc. to allow the exhaust gas from the forming tube to expand. These mufflers also have a pair of stamped outer shells that enclose and enclose the inner plate to form a chamber. The chamber forms a single enclosed volume in which the exhaust gas expands. This general-purpose prior art muffler is a British patent
632013, British Patent No. 1012463, British Patent No. 4132286.

Some prior art mufflers are formed from three or more stamping forming elements and additionally a plurality of tubular elements. For example, the aforementioned U.S. Pat. No. 4,132,286 shows a muffler having a perforated inner plate, which is stamped to form at least one groove. A conventional tube member that fits the type of groove in the perforated plate is supported and retained by the groove. The muffler of U.S. Pat. No. 4,132,286 further includes a pair of opposing stamped outer shells that effectively form a bivalve surrounding the perforated inner plate and the tube supported therein. The muffler shown in U.S. Pat. No. 4,132,286 effectively forms only one inner chamber in which the exhaust gas expands. The acoustic articulation capability of this general-purpose muffler is extremely limited, and it is not possible to achieve the muffler's noise-damping requirements for many vehicles manufactured and sold in the US as the muffler shown in U.S. Pat. It's extremely difficult.

A muffler similar to the muffler shown in U.S. Pat. No. 4,132,286 is shown in British Patent No. 2120318. In particular, British Patent No. 2120318 shows a muffler having a plurality of tubes supported in parallel rows by a plurality of laterally extending baffles. The row of tubes and baffles are placed in a generally bivalve-shaped oppositely stamped outer shell. However, the outer shell shown in British Patent No. 2120318 is a highly complex stamped part which further forms both stamped exhaust pipes and stamped tailpipes. The stamped outer bivalve shell and the stamped exhaust and tailpipes integral therewith require extremely expensive dies. Moreover, the internal components required by GB 2120318 inherently require a combination of tubes and separate baffles that must be assembled within the labor intensive fabrication process described above for prior art mufflers.

Yet another prior art muffler incorporating both tubular and stamping elements is shown in JP 59-43456. Unlike the two described above, the muffler shown in JP 59-43456 has at least 4 stamping elements associated with tubular elements. In particular, JP-A-59-43
The muffler shown in the '456 publication has a pair of stamped inner plates with formed grooves that form tubes when the inner plates are placed in face-to-face relationship. Moreover, each inner portion is bent at a substantially right angle to the rest of the plate to form a laterally extending wall in the stamped forming tube. Separate stamped baffles are also provided. The muffler shown in Japanese Patent Laid-Open No. 59-43456 further has a pair of stamped outer bivalve shells surrounding the inner plate. The outer bivalve shell and the bent portion of the inner plate form a complementary shape, and the bent portion of the inner plate forms a baffle in the muffler. The muffler further has a tubular member extending between the outer shell and the baffle formed by the folded portion of the inner plate. JP 59
The muffler disclosed in the -43456 publication is extremely complicated, expensive, and difficult to assemble. Especially this muffler is at least 4
It has individual stamping forming elements and correspondingly requires a specialized die and a pair of separate tubular members. The stamped inner plates must be assembled and welded together. The separate tubular members must be firmly joined to the stamped inner side, such as by welding. Also, separate baffles must be firmly attached to the stamped inner plate. Opposing bivalve shells must be securely assembled around a subassembly of opposing stamped inner plates, separate baffles and separate tubes.

SUMMARY OF THE INVENTION The prior art stamped and formed muffler described above offers certain advantages over conventional mufflers having a wrap-type outer shell.
In particular, most of the stamped mufflers described above are lighter than ordinary mufflers and can be manufactured by a process that is well suited for automation.
However, many of the prior art stamping mufflers described above have not generally achieved a degree of acoustic articulation acceptable for vehicles manufactured or sold in the United States. As a result, until recently stamped mufflers have not achieved sufficient commercial success in the United States.

Recently, there have been some considerable advances in stamping mufflers. In particular, U.S. Pat. No. 4,700,806 shows a muffler formed from stamped forming elements, which combines at least one articulation tube and at least one low frequency resonant chamber.
One embodiment of the muffler shown in U.S. Pat. No. 4,700,806 shows a pair of inner plates formed to form a groove therein.
The plates are attached to each other such that the grooves form rows of tubes. Holes or other opening devices are provided in selected portions of the groove to control the expansion of exhaust gas flowing through the formed tube. U.S. Patent No. 4700
The 806 muffler also has a pair of outer shells. In the above embodiment, the outer shell has a peripheral portion and a fold line joining the spaced portions on the peripheral portion. The folds are formed to contact the inner plate substantially continuously between the peripheral portions of the outer shell. Therefore, the folds shown in U.S. Pat. No. 4,700,806 effectively form a baffle, which allows multiple chambers to be formed by the outer shell. The location of the folds shown in U.S. Pat. No. 4,700,806 is selected by the volume of the chamber required for specific noise attenuation and exhaust gas flow characteristics.

Other improvements related to stamped mufflers are US Pat. No. 4,736,817, US Pat. No. 4,754,423, US Pat. No. 4,760,89.
No. 4, U.S. Pat. No. 4,765,437.

The muffler produced by the four US patents mentioned above has achieved considerable commercial success in a very short time. All of this commercial success relates to the original equipment muffler where the number of mufflers of a particular type is sufficient to easily offset the price associated with stamping. However, it is anticipated that there are some cases where the volume of the muffler is low, thereby increasing the price per muffler for the four stamping dies required for the four stamping forming parts of the muffler. It is also anticipated that in some cases the exhaust gas flow may require correct and uncomplicated acoustic articulation. For these cases, it would be desirable to have a muffler that has a very low initial manufacturing cost, low material cost, and is manufacturable, yet still obtains the highly desirable benefits of a manufacturing process well suited for automation. Moreover, it is well known that weight reduction can improve fuel efficiency and other aspects of engine performance. It is therefore desirable to have a lightweight vehicle element if possible.

The object of the invention is therefore to obtain an exhaust muffler with a considerably smaller number of elements. The next object of the invention is to obtain a very lightweight muffler and exhaust system. A further object of the invention is to obtain a muffler which has stamping elements, but which has a low die cost. Yet another object of the invention is to obtain a muffler that facilitates automation of welding of muffler elements ,. A further object of the invention is to obtain a muffler having a monolithic construction and having baffles integral with the outer shell for supporting the tubular elements of the muffler.

SUMMARY OF THE INVENTION The present invention is directed to an exhaust muffler having a pair of opposing outer shells each formed to define a plurality of chambers. The outer shell is formed by stamping or other known metal forming techniques. Each outer shell is formed to form a peripheral portion that is a peripheral flange. The peripheral part is placed so that it lies substantially in one plane. The peripheral portions of the two formed outer shells are dimensioned to lie substantially in registration with each other, allowing opposing peripheral portions to be securely attached to each other.

Operation The outer shell is formed to extend between a pair of spaced-apart peripheral portions of the outer shell to form at least one baffle fold connecting them. The base of the baffle fold has a plurality of non-linear sections, at least some of which are dimensioned to surround and tightly engage the tubes in the muffler as described below. The folds in the outer shell lie substantially in line with each other so that the portion of the base of the baffle fold in one outer shell is in face-to-face contact with the corresponding portion of the base of the baffle fold in the outer shell. Each outer shell has a plurality of baffle folds, each fold in one outer shell being substantially coincident with a corresponding fold in the other outer shell. Each base of this baffle fold in one outer shell contacts a corresponding portion of the base of each baffle fold in the other outer shell. The non-linear portion of the baffle fold may be of any shape, but is preferably approximately semi-circular or semi-cylindrical and dimensioned to securely engage a generally cylindrical tube. The non-selected portion of the baffle fold is sized to control communication between the chambers. In particular, the non-straight part of the baffle fold forms a stamped tube.

A portion of the outer shell is further configured to engage at least one inlet pipe to the muffler and at least one outlet pipe from the muffler. The portion of the outer shell that engages the inlet and outlet pipes is generally adjacent to the peripheral portion of each outer shell and is generally semi-circular or semi-cylindrical or other shape to fit the pipe.

The remaining portion of the outer shell forms a shape that is selected to fit the available space on the vehicle. At least one of the outer shells has a concave conforming region shaped to conform to a convex structure on the vehicle. The outer shells are preferably symmetrical with respect to each other and can form a pair of combinable outer shells from a set of stamping dies.

The muffler also has an array of tubes that are at least partially located within the muffler. The tubes in the rows are supported within the outer shell by the non-linear portions of the baffle folds formed within the outer shell. The at least selected tube is further supported by the inlet and outlet portions of the outer shell. Controlling the inflow and / or expansion of exhaust gas into the expansion chamber partially formed by the baffle folds of the outer shell from which rows of holes, staggered windows, openings, etc. are provided in selected portions of each tube. Can be done. At least one tube in the muffler forms an articulation tube, the articulation tube is placed in communication with an enclosed low frequency resonant chamber formed in part by the baffle fold of the outer shell. At least one tube extends outwardly from the muffler and forms a continuous, integral exhaust or tail pipe. A continuous, integral exhaust pipe and / or tail pipe located in the muffler has the above-mentioned holes, armor windows, openings or other devices from which exhaust gas can flow. The portion of the continuous exhaust pipe or tail pipe placed inside the muffler and / or that portion placed outside the muffler may not be straight.

The outer shells tightly engage each other and around the muffler tube. The outer shells are preferably attached directly to each other at least at selected locations along the portions of the baffle folds that are in face-to-face contact with each other. Therefore, the opposing baffle folds form a structurally and functionally integral baffle, but are also integral with their respective outer shells. Tightly joining the outer shells to each other is done by welding or by a suitable mechanical joining device.

The preferred fabrication and assembly method includes forming the outer shell inlet, outlet, and baffle folds to align with selected non-linear portions. The outer shells are then joined to each other by welding or a suitable mechanical interconnection device. A tube having an apertured window or the like formed therein is inserted into the inlet or outlet opening sufficiently to be supported thereby by the non-linear portion of the aligned baffle fold. The tube is then welded to the peripheral portion of the outer shell.

EXAMPLE A muffler according to the present invention is shown generally at 10 in FIGS. The muffler 10 has outer shells 12, 14 which are formed from a unitary metal sheet such as aluminized steel, plated steel or stainless steel or from a suitable non-metallic material. The muffler 10 further comprises tubes 16, 18 which are at least partially located within the muffler 10. As described herein, the tubes 16 and 18 extend integrally with the muffler 10 to the exterior and each form at least a portion of an exhaust pipe and a tail pipe. However, in a particular embodiment, the tubes 16, 18 terminate near the perimeter of the muffler 10, thereby forming the muffler inlet and outlet. At least one separate exhaust pipe and tail pipe are coupled to the muffler inlet and outlet. The portions of the tubes 16,18 that are placed in the muffler 10 are provided with holes 20,22, which are selectively sized to control the flow of exhaust gas from the tubes 16,18 as described below. According to the customary practice in industry, the holes 20, 22 can be replaced by other devices such as a louvered window, an opening through which the exhaust gas can expand.

The outer shells 12, 14 are shown to be substantially symmetrical to each other. As a result, one stamping die can be used to form both outer shells 12,14. The use of nearly identical outer shells 12,14 further simplifies inventory management. In many embodiments, however, a symmetrical shape of the outer shells 12,14 is not possible and needs to be different depending on vehicle specifications. However, in these cases, the outer shell is Japanese Patent Application No.
It may be stamped using an insert die and a die subset, as shown in −41461. Proper use of die subsets and insert dies can also significantly reduce the investment in the die for stamping outer shells of similar but different shapes.

The outer shell 12 has a flange 24 that is substantially flat. The arcuate inlet flange 26 and the arcuate outlet flange 28 extend away from the flat portion of the peripheral flange 24 and form the inlet and outlet portions of the muffler 10 as described below. Outer shell
12 further includes baffle folds 30 that join the peripheral flanges 24 at spaced locations. In particular, the baffle fold 30 has flat bases 32,34,36 and arcuate sections 38,40. The flat portions 32,3436 of the baffle fold 30 lie substantially in the same plane as the peripheral flange 24. However, the arcuate sections 38, 40 are sized to extend from the surface of the peripheral flange 24 and engage the tubes 16, 18 as described below.

Outer shell 12 is characterized by further having formed chambers 42.44, which extend from the surface formed by peripheral flange 24. The chambers 42,44 are each characterized by having concave sections 46,48, which are sized to approximately conform to the shape of a convex structure on the vehicle on which the muffler 10 is mounted. Recesses 46,48 further function to strengthen chambers 42,44, thereby reducing noise associated with vibration of outer shell 12. However, in many embodiments of the muffler 10, the outer shells 12 and 14 have
A plurality of reinforcing grooves are provided as shown in 3-305129.

The outer shell 14 is substantially symmetrical to the outer shell 12 as shown in FIGS. However, this symmetrical outer shell 12, 14 is not absolutely necessary and is not possible with many mufflers. The outer shell 14 has a generally flat peripheral flange 54 dimensioned to lie substantially coincident with the peripheral flange 24 of the outer shell 12. The peripheral flange 54 is characterized by having inlet and outlet flanges 56, 58, which are the outer shell 1
Positioned to match the two inlet and outlet flanges 26,28.
Outer shell 14 also has a substantially flat section 62.64.66 and an arcuate section.
It has a baffle fold 60 formed by 68 and 70.
The flat portions 62, 64, 66 of the baffle fold 60 lie in the same plane as the flat peripheral flange 54 and are dimensioned for face-to-face contact with the flat portions 32, 34, 36 of the baffle fold 30 of the outer shell 12. Get burned. Similarly, the bows 68,70 of the baffle fold 60 lie substantially in line with the bows 38,40 of the baffle fold 30 of the outer shell 12.

The outer shell 14 further includes a chamber 7 extending from the peripheral flange 54.
Has 2,74. The chambers 72 and 74 are characterized in that they are concavely formed inwardly and have concave portions 76 and 78, respectively. In a typical muffler, it is not necessary to have mating parts on the opposing outer shells. However, the provision of the mating concave portions 76, 78 contributes to the strengthening of the outer shell 14 and allows the use of substantially identical die subsets for forming the outer shells 12, 14.

The muffler 10 is assembled into the shape shown in FIGS. 2-5 by first placing the exhaust pipe 16 and tail pipe 18 in proper position within the outer shell 14. In particular, the exhaust pipe 16 is placed in the bow-shaped inlet flange 56 of the baffle fold 60 and the bow-shaped portion 70 so that the row of holes 20 is substantially aligned with the chamber 72, and the end 80 of the exhaust pipe 16 is the chamber. It is mounted so that it can be placed in 74. Similarly, the tailpipe 18 is mounted within the outlet flange 58 and the bow 68 of the baffle fold 60. The rows of holes 22 are placed to lie in the chamber 74 while the tail pipes 18
The end 82 of the is placed in the chamber 72.

The outer shell 12 is then attached to the outer shell 14 and the peripheral flange 2
4,25 are mounted so that they match each other and have a face-to-face relationship. The inlet and outlet flanges 26,2 of the outer shell 12 in this direction
8 winds up the exhaust pipe 16 and the tail pipe 18, respectively, and engages them. Moreover, the bow-shaped portions 38, 40 of the baffle fold 30 within the outer shell 12 substantially surround and engage the tail pipe 18 and exhaust pipe 16, respectively. In this assembled condition, the flat portions 32, 34, 36 of the baffle fold 30 are in substantially face-to-face contact with the flat portions 62, 64, 66 of the baffle fold 60, respectively. The juxtaposed flat parts 32, 34, 36 and 62, 64, 66, respectively, are firmly connected to each other, for example by spot welding. In the preferred embodiment, multiple spot welds are used to interconnect the juxtaposed pairs of flat portions 32,34,36 and 62,64,66.

The assembly is completed by tightly connecting the outer shells 12,14 to each other around their respective peripheral flanges 24,54. The connection of the peripheral flanges 24, 54 is preferably by welding such as seam welding. Welding is relatively easy due to the double thickness of metal on the peripheral flanges 24,54 and flats 32,34,36 and 62,64,66. The exhaust pipe 16 is then firmly welded to the inlet flanges 26,56 and the tail pipe 18 is similarly welded to the outlet flanges 28,58. Welding the exhaust and tail pipes 16 and 18 to the rest of the muffler 10 is easily performed by robot welding equipment.

Outer shell 1 as an alternative to the above assembly process
It is possible for the 2,14 to be firmly joined together before placing the exhaust pipe 16 and the tail pipe 18 therein. Exhaust pipe
The 16 can then be slid and inserted between the inlet flanges 26,56 a sufficient distance to be properly supported by the arcuate portions 40,70 of the baffle folds 30,60, respectively. Similarly, the tailpipe 18 can be slidably inserted between the outlet flanges 28,58 a sufficient distance to be supported by the arcuate portions 38,68 of the baffle folds 30,60, respectively. The exhaust pipe 16 and the tail pipe 18 are connected to the inlet flange 2 by welding, for example.
6,56 and outlet flanges 28,58 firmly attached. According to this embodiment, the exhaust pipe 16 and the tail pipe 18 are supported by the fold lines 30,60 and are not mechanically connected thereto. Therefore, the exhaust pipe 16 and the tail pipe 18 can easily expand in response to the heat generated by the exhaust gas flow through the muffler 10.

It is emphasized that the muffler 10, shown in detail in FIGS. 2-5, provides a lightweight, extremely simple construction, a fairly small amount of metal, and an extremely simple fabrication tool. In particular, unlike many prior art mufflers, muffler 10 does not have a flat metal plate portion extending between the muffler tube and the peripheral portion. Rather,
The tube has a strip structure that is completely separated from the peripheral part of the muffler except at the inlet and outlet. Moreover,
Unlike some prior art mufflers, the muffler specifically shown in FIG. 5 has baffles formed by baffle folds 30,60 integral with the outer shells 12,14, respectively. Therefore, it is not necessary to provide a separate baffle device used in prior art mufflers with tubular inner elements. The installation of the baffle folds 30,60 integral with the outer shells 12,14 significantly reduces the number of elements required for the muffler and makes the muffler assembly extremely easy. Moreover, the opposing baffle fold 3
Attaching 0 and 60 firmly to each other contributes to the muffler's bufffire resistance.

An alternative, slightly more complex muffler 90 is shown in FIGS. Muffler 90 has opposing outer shells 92,9
4 It has an exhaust pipe 96 and a tail pipe 98. The outer shell 92 is formed to form a generally flat peripheral flange 100 having an arcuate inlet flange 102 and an arcuate outlet flange 104. The outer shell 92 is further formed to define a generally centered expansion chamber 106 and low frequency resonant chambers 108, 110. Baffle folds 112 and 114 are low-frequency resonance chambers 108 and 110, respectively.
To separate the expansion chamber 106. The folds 112, 114 have flat portions 116, 118, respectively, which lie substantially in the same plane as the peripheral flange 100. Moreover, folds 11 as in the previous embodiment
2, 114 are provided with bow-shaped portions for engaging the exhaust pipe 96 and the tail pipe 98, respectively.

The outer shell 94 has a generally flat peripheral flange 120 having an arcuate inlet flange 122 and an arcuate outlet flange 124. Expansion chamber 126 and low-frequency resonance chamber 128,1 placed approximately in the center
30 extends from the peripheral flange 120. The expansion chamber 126 is separated from the low frequency resonant chambers 128 and 130 by baffle folds 132 and 134, respectively. Baffle folds 13 as you can see in Figure 7
2 is a flat part that lies in the same plane as the peripheral flange 120
It is formed by 136, 138 and 140. The arcuate portion is located within fold 132 and extends from the surface formed by peripheral flange 120 to support exhaust pipe 96 and tail pipe 98.
Similarly and as shown in FIG. 7, the baffle folds 134 are flat portions 146,148,1 that lie in the plane of the peripheral flange 120.
50 and an arcuate portion extending from the surface of the peripheral flange 120 for supporting the exhaust pipe 96 and the tail pipe 98. The baffle folds 132,134 of the outer shell 94 are positioned to approximately match the baffle folds 112,114 of the outer shell 92. The expansion chamber 126 of the outer shell 94 is therefore
Of the expansion chamber 106. Moreover, the low frequency resonant chambers 128, 130 of the outer shell 94 match the corresponding low frequency resonant chambers 108, 110 of the outer shell 92.

The exhaust pipe 96 has a row of holes 152 that are placed to lie in the expansion chambers 106,126. The portion of the exhaust pipe 96 that is placed to lie in the low frequency resonant chamber 110, 130 is substantially holeless and is bent to achieve a length that properly attenuates the selected low frequency noise narrow range. Exhaust pipe 96
The end portion 154 of the is placed to lie in the low frequency resonant chamber 110, 130.

Similarly, the tailpipe 98 is provided with an array of holes 156 that lie in the expansion chambers 106,126. The portion of the tape pipe 98 that is placed in line with the low-frequency resonance chambers 108 and 128 has almost no hole and is substantially straight. Tail pipe 98
The end 158 of the is placed to lie in the low frequency resonant chamber 108, 128.

In the muffler embodiment clearly shown in FIG. 7, it can be seen that the exhaust pipe 96 and the tail pipe 98 have a curved bend at the entrance to the muffler 90 on the outside of the muffler. The specific direction of the curve in the exhaust pipe 96 and the tail pipe 98 is
It depends on the shape of the available space under the vehicle.

The muffler 90 is assembled in substantially the same manner as the muffler 10 described above.
In their assembled state, the outer shells 92,94 are securely joined together at the flat portions of the baffle folds 112,114, around the peripheral flanges 100,120. In this embodiment, the baffle folds 112,132 connect the expansion chambers 106,126 to the low frequency resonant chambers 108,128.
It functions as an integrated baffle that separates from. Similarly, the baffle folds 114 and 134 connect the expansion chambers 106 and 126 to the low frequency resonance chamber 110,
Acts as an integrated baffle to separate from 130.
As mentioned in the previous embodiment, each baffle is integral with the rest of the outer shells 92,94, thereby considerably simplifying the muffler 90 compared to prior art mufflers with separate baffles. .

In the assembled muffler 90, the exhaust pipe 96 terminates in the low frequency resonant chambers 110, 130 and acts as an articulation tube to damp the low frequency range of the much less noisy noise. The particular frequency is determined in part by the volume defined by the low frequency resonant chambers 110, 130, by the cross-sectional area of the pipe 96 and by the distance between the hole 152 and the end 154 of the exhaust pipe. Similarly, the end of the tail pipe 98 acts as an articulation tube leading into the low frequency resonant chamber 108,128. Exhaust gas flows through exhaust pipe 96 and into expansion chambers 106, 126 through holes 152.
Exhaust gas flow continues through hole 156 in tail pipe 98. The volume of the exhaust gas flow determines the cross-sectional area of the exhaust pipe 96 and the tail pipe 98, and the total area required for the upper holes 152 and 156 thereof. In particular embodiments, shapes other than circular holes 152, 156,
For example, round windows or large openings are also desirable.

Another alternative muffler is generally referred to in FIGS. 8 and 9.
Shown at 200. The side view of the muffler 200 is substantially the same as the side view of the muffler 90 shown in FIG. Especially the muffler 200
Has a first and a second outer shell 202, 204 distribution pipe 206 and a tail pipe 208. For ease of explanation, it is assumed that the outer shells 202,204 are substantially identical and symmetrical about the two orthogonal axes. However, in many examples of mufflers,
This symmetry is significantly hindered by the shape of the available space envelope on the vehicle.

Referring to FIG. 9, the outer shell 204 is stamped to form a generally flat peripheral flange 210 from which generally semi-cylindrical inlet and outlet grooves 209, 211 extend. The chambers 212, 214, 216 are also formed to extend from the surface of the peripheral flange. Chambers 212, 214, 21 as in the previous embodiment
The volume of 6 largely depends on the engine exhaust flow and noise characteristics, while the shape of the chambers 212, 214, 216 depends on the shape of the available space on the vehicle. Chambers 212 and 214 have baffle folds 2
18 are separated from each other, while the chambers 214, 216 are separated from each other by baffle fold 220. Baffle fold 218
Is characterized by having substantially flat portions 222,224,226,228 generally lying in the same plane as the perimeter flange 210.
Baffle fold 218 is more uneven 230,232,234
It is characterized by having. As shown in FIG. 9, the uneven portions 230 and 232 of the baffle fold 218 are uneven portions.
Placed on each side of 234.

Baffle fold 220 is a flat section 242,244,246,248
And an uneven portion 250, 252, 254. The uneven portions 250, 252 are placed on either side of the uneven portion 254, respectively. Additionally, the non-planar portion 250 is generally co-linear with the non-planar portion 230 and the exit groove 211, while the non-planar portion 252 is generally co-linear with the non-planar portion 232 and the inlet groove 209. Moreover, the non-planar portions 230,250 outlet grooves 211 are substantially the same size and shape, while the non-planar portions 232,252 inlet grooves 209 are substantially the same size and shape. Non-flat portion 23 in the exemplary embodiment
The 0, 232, 250, 252 and the inlet and outlet grooves 209, 211 have a substantially semi-cylindrical shape, and form a cross section substantially corresponding to the outer dimensions of the exhaust pipe 206 and the tail pipe 208. Uneven portion 234,
252 is shown to have a smaller cross-section than the uneven portions 230,232,250,252. However, the relative dimensions of the non-planar portions depend exclusively on the exhaust flow and noise characteristics of the engine to which the muffler is coupled.

The exhaust pipe 206 is substantially straight inside the muffler 200 and extends to a position outside the muffler 200. The outer portion of the exhaust pipe 206 may be straight or non-straight, depending on the requirements of the exhaust system.
Exhaust pipe 206 is an end placed to lie in chamber 216.
Has 258. Exhaust pipe 206 further has a row of holes 260 spaced inwardly from end 258 of exhaust pipe 206 and located at selected locations along the same. The total area enclosed by hole 250 is selected by the noise attenuation requirements of muffler 200.
The hole 260 is placed to lie in the chamber 214. Similarly, the tail pipe 208 is located at the end 26 which is placed to lie in the chamber 212.
With 2. The tail pipe 208 is also a chamber 214 of the muffler 200.
Having a row of holes 262 positioned to lie therein.

As mentioned above, the outer shell 202 shown in FIG. 8 is substantially identical to the outer shell 204. However, the outer shell 202,204
There may be differences between the two, and the shape of each is determined by the space availability of the vehicle. But often,
The baffle folds 218, 220 of the outer shell 204 are the outer shell 20
Aligned approximately with the corresponding baffle fold of 2. Moreover, the baffle folds of the outer shell 202 preferably have non-linear portions that are positioned to engage the exhaust pipe 206 and the tail pipe 208.

The muffler 200 is first assembled by mounting the outer shells 202,204 together around their peripheral flanges, preferably at opposite flat portions of the baffle folds 218,220. The inlet groove 209 of the outer shell 204 and the opposing inlet groove of the outer shell 202 form the inlet to the muffler 200 as shown in FIG. Similarly, the outlet groove 211 of the outer shell 204 and the outer shell 20
The two matched exit grooves form the exit from the muffler. The strong connection between the outer shells 202 and 204 is made by welding.
Or by any suitable mechanical interconnection such as pleating or roll forming.

The exhaust pipe 206 is then slid axially through the inlet and through the non-linear portions 232, 252 of the outer shell 204 and the corresponding mating non-linear portions of the baffle folds of the outer shell 202. In particular, the axial movement of the exhaust pipe 206 is sufficient to place the end 218 of the exhaust pipe 206 in the chamber 216 and the hole 260 in the chamber 214.

Similarly, tailpipe 208 is axially inserted into the outlet of muffler 200 through non-linear portions 230,250 of baffle folds 218,220 and corresponding non-linear portions of outer shell 202, respectively. In particular, the insertion of the tail pipe 208 into the muffler 200 is sufficient to place the end 262 of the tail pipe 208 in the chamber 212 and the hole 264 in the chamber 214.
The opposite outer ends of exhaust pipe 206 and tail pipe 208, respectively, are then suitably joined to other portions of the exhaust system.

As is best shown in FIG. 9, the flow enabled by the muffler 200 is extremely high in the well-known three-stream muffler made of a conventional wrapping outer shell and at least three tubes and separate rows of baffles. Similar In particular, some of the exhaust gas flowing through the exhaust pipe 206 passes through the hole 260 and is
Spill into 214. The remaining exhaust gas enters the flow chamber 216 at the end of the exhaust pipe 206. Gas entering the chamber 216 flows through a forming tube formed by the non-linear portion 254 of the baffle fold 220, the corresponding non-linear portion of the baffle fold in the outer shell 202. Gas entering chamber 214 through holes 260 or from chamber 216 mixes and flows directly into holes 264 and / or is formed by the non-linear portion 234 of baffle fold 218 of outer shell 204 and the corresponding non-linear portion of shell 202. Flow through the forming tube. Exhaust gas flowing through the forming tube formed by the non-straight portion 234 and the corresponding portion of the outer shell 202 continues to flow into the end 262 of the tail pipe 208 toward the outlet of the exhaust system. The gas entering at the end 262 of the tail pipe 208 is
It mixes with the gas entering the tailpipe 208 at hole 264. The relative mixing of the exhaust gases within the muffler 200 depends on the careful selection of the cross-sectional areas of the holes 260,264 and the non-straight portion of the outer shell 204.
It can be controlled by the relative selection of the cross-sectional dimensions of the forming tube formed by 34,254 and the corresponding non-straight sections of the outer shell 202.

The muffler 200 shown in Figures 8 and 9 allows for a gas flow mode that is desirably wide with only four elements. This is a minimum of 9 to achieve this same flow pattern.
It is sharply contrasted with prior art wrap-around outer shell mufflers which require individual parts. Although the above all stamped muffler also achieves this same flow pattern with four parts, these are often heavier mufflers,
The initial capital cost is somewhat higher due to the stamping die. It can also be seen that the gas flow pattern of the muffler 200 shown in FIGS. 8 and 9 can be greatly varied by having the forming tube in only one of the matched pairs of baffle folds. For example, the baffle fold 220 of the outer shell 204 can have a continuous flat portion between the non-linear portions 250,252. The baffle folds of the outer shell 202 that match the baffle folds 220 may be substantially the same shape. In this embodiment, the portion of exhaust pipe 206 between hole 260 and end 258 forms an articulation tube. Therefore, the chamber 216 forms a low frequency resonant chamber. All exhaust gas flowing through exhaust pipe 206 is forced through chamber 260 into chamber 214. Some of this gas flows directly into the tailpipe 208 through holes 264, while other parts of the exhaust gas baffle fold 21.
Flow into chamber 212 through a tube partially formed by eight non-straight portions 234. This gas continues to flow from the chamber 212 into the end 262 of the tailpipe 208. The relative proportions of exhaust gases that take these alternative flow paths to the tail pipe 208 can be controlled by choosing the cross-sectional areas of the non-straight portion 234 and the hole 264, respectively.

As described above, according to the present invention, the muffler is provided with the pair of outer shells and the pair of pipes. Each of the outer shells has a peripheral flange and a plurality of chambers extending from the peripheral flange. The chambers are separated from each other by baffle folds, and the baffle folds of each outer shell have juxtaposed portions that generally abut one another and abut each other in a generally face-to-face relationship. The pipe in the muffler has a hole, an armored window, an opening, etc., and can control the expansion of exhaust gas from this. Devices such as openings are placed at selected locations with respect to the chamber formed in the muffler. The pipe in the muffler extends continuously beyond the muffler and forms an integral part of the exhaust pipe and tail pipe of the exhaust system. The outer shell is assembled,
The pipe is inserted axially into the assembled outer shell. The baffle folds effectively separate the chambers and are integral with the rest of the outer shell, contributing to a more efficient welding process and backfire resistance.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a muffler according to the present invention, FIG. 2 is a side view of an assembled mold of the muffler of FIG. 1, and FIG.
FIG. 4 is a sectional view taken along line 3-3 in FIG. 4, and FIG.
4 is a sectional view taken along line 5-5 of FIG. 3, FIG. 6 is a side view of another embodiment of the muffler according to the present invention, and FIG. 7 is taken along line 7-7 of FIG. Sectional view at 8th
FIG. 9 is an end view of a third embodiment of the muffler according to the present invention, and FIG. 9 is a sectional view taken along line 9-9 in FIG. 10 …… muffler, 12,14 …… outer shell, 16,18 …… tube, 20,22 …… hole, 24,26,28 …… flange, 30 …… fold, 32,34,36 …… base, 38,40 …… Bow-shaped section, 42,44 ……
Chamber, 46,48 ... concave, 54,56,58 ... flange, 60 ... crease, 62,64,66 ... part, 68,70 ... end, 72,74 ... chamber, 76, 78 …… Concave, 80,82 …… End, 90 …… Muffler, 92,94 …… Outer shell, 96,98 …… Pipe, 100,102,104 …… Flange, 106,108,110 …… Room, 11
2,114 …… folds, 116,118 …… parts, 120,122,124 ……
Flange, 126,128,130 …… Room, 132,134 …… Fold, 13
6,138,140 …… part, 146,148,150 …… part, 152 ……
Hole, 154 ... end, 156 ... hole, 158 ... end, 200 ... muffler, 202,204 ... outer shell, 206,208 ... pipe, 21
0 …… Flange, 209, 211 …… Groove, 212, 214, 216 …… Chamber, 2
18,220 …… Folds, 222,224,226,228,230,232,234,242,
244,246,248,250,252,254 …… Part, 258 …… End, 260
... hole, 262 ... end, 264 ... hole.

Claims (11)

(57) [Claims] 1. A lightweight exhaust muffler comprising a pair of generally tubular pipes having perforations extending therethrough for allowing exhaust gas to flow therethrough and a pair of formed outer shells. Each of which has a peripheral portion, said peripheral portions of said outer shell being securely coupled to each other, each of said outer shell being further formed therein,
A plurality of chambers extending from the peripheral portion, wherein the chambers of each of the outer shells are integral with the respective outer shells and extend between spaced locations on the peripheral portion of the outer shells. Separated from each other by a baffle fold that joins them, the baffle folds of the outer shell being substantially coincident with each other and formed in the at least one mating fold around the portion of the pipe that surrounds and engages the pipe of the muffler. And a non-linear portion forming a forming tube extending between the chambers of the muffler separated from the matching folds and separated by the baffle folds. 2. The muffler according to claim 1, wherein the aligned baffle folds are attached in face-to-face contact with each other. 3. The exhaust muffler of claim 1, wherein each of the outer shells has three chambers formed therein and two baffle folds, each adjacent outer shell. An exhaust muffler in which the chambers are separated from each other by the baffle folds and the non-linear portions are located in at least one of the baffle folds to provide communication between the at least two chambers. 4. The exhaust muffler of claim 1, wherein the outer shell is securely welded in face-to-face relationship with each other at a plurality of locations along each of the baffle folds. 5. The exhaust muffler according to claim 1, wherein each of the pipes has an integral structure. 6. The exhaust muffler according to claim 5, wherein at least one of the pipes extends integrally to the outside of the muffler. 7. The exhaust muffler according to claim 6, wherein a portion of the pipe placed outside the muffler has a non-linear shape. 8. The exhaust muffler according to claim 6, wherein the pipe portion in the muffler has a linear shape. 9. A lightweight exhaust muffler comprising a pair of monolithic pipes having opposing ends, each of said pipes being separated from said ends to allow a flow of exhaust gas therethrough. Having an opening device extending therethrough and further having a pair of opposing outer shells rigidly coupled to each other, each of the outer shells forming a peripheral flange and a plurality of chambers extending from the peripheral flange. Integrally formed, the chambers are integrally formed in each of the outer shells and are separated from each other by baffle folds extending between and spaced apart on the peripheral flange to join them. The respective baffle folds of the outer shell are substantially coincident with each other, and each of the baffle folds is in flat contact with the flat portion of the corresponding baffle fold in face-to-face relationship. The baffle fold further includes an uneven portion extending from the flat portion, the selected uneven portion engaging and supporting the pipe of the muffler and at least one An exhaust muffler forming a forming tube that separates the uneven portion from the pipe and connects the two chambers. 10. The exhaust muffler of claim 9, wherein each of the outer shells is formed to define three chambers and two baffle folds. 11. The exhaust muffler of claim 10 wherein each of the baffle folds has one of the non-straight portions spaced apart from the pipe.