JP3758521B2 - Exhaust muffler - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust muffler in which an outer shell portion is formed by a cylindrical outer shell body and end plates that close both ends thereof, and more particularly to an exhaust muffler in which a silencer is laid on the inner wall surface of the end plate.
[0002]
[Prior art]
An exhaust muffler provided in an exhaust system of an internal combustion engine is provided with an expansion chamber for expanding an exhaust gas cross-sectional area or a plurality of internal pipes in order to reduce an exhaust pressure wave by changing a cross-sectional area of an exhaust gas passage. Alternatively, a plurality of expansion chambers are provided to branch the exhaust gas flow path so that pressure waves interfere with each other or resonate at a specific frequency.
Furthermore, if the pressure wave of the exhaust gas flowing into the expansion chamber of the exhaust muffler directly passes through the outer shell and diffuses to the outside, it becomes a noise source, or if high temperature exhaust gas directly hits the inner wall of the outer shell, The shell body and end plate repeatedly undergo thermal expansion and contraction due to cooling, and the wall surface of these outer shells fluctuates and deterioration with time is promoted. Therefore, sound absorbing materials are often laid on the inner wall of the outer shell, etc. .
[0003]
For example, in the exhaust muffler disclosed in Japanese Utility Model Laid-Open No. 06-87619, the rear end side of the cylindrical outer frame 100 is closed by an end plate 110 as shown in FIG. The sound deadening material layer 130 and the inner plate 140 joined to the inner wall of the outer plate 120 are stacked. Further, as shown in FIG. 8 (b), an end plate 150 that closes the rear end of the cylindrical outer frame of the exhaust muffler sandwiches the outer plate 160, a silencer layer (not shown) and the silencer layer, and then the outer plate. There is known a configuration having an inner plate 170 in which an outer peripheral flange 171 is welded in the vicinity of the outer peripheral end of 160.
[0004]
[Problems to be solved by the invention]
However, when the inner plate 140 of the end plate is directly welded to the inner wall surface of the cylindrical outer frame 100 as in the exhaust muffler shown in Japanese Utility Model Laid-Open No. 06-87619, the inner plate 140 directly receives the high temperature exhaust gas. When the thermal expansion and the shrinkage due to cooling are repeated, stress concentration is repeatedly applied to the welded portion (* marked portion shown in FIG. 8A) with the cylindrical outer frame 100, and the deterioration with time in the vicinity of the welded portion proceeds. End up. Similarly, as shown in FIG. 8B, when the outer peripheral flange 171 of the outer plate 170 sandwiching the sound deadening material layer is welded to the outer plate 160 of the end plate, the inner plate 170 directly receives the high-temperature exhaust gas to generate heat. When the expansion and the contraction due to cooling are repeated, the reaction force accompanying the expansion and the contraction is applied to the welded portion (the w portion shown in FIG. 8B) with the outer plate 160, and the stress concentration is repeatedly applied to the welded portion w. In addition, the deterioration in the vicinity of the welded portion progresses with time, and the joint portion w between the inner plate 170 and the outer plate 160 may peel off, which is a factor of reducing the durability of the exhaust muffler.
[0005]
The present invention is based on the above-described problems, wherein an end plate constituting an outer shell portion of an exhaust muffler is formed by sandwiching a sound deadening material layer between an inner plate and an outer plate, and the inner plate and the outer plate of the end plate. An object of the present invention is to provide an exhaust muffler with improved durability by allowing the relative displacement of.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, at least one of the end plates for closing both ends of the cylindrical outer shell body is provided with an outer plate and an inner plate attached to the inner wall surface of the outer plate via a sound deadening material layer. In the exhaust muffler, a flange is formed to extend to the periphery of the inner plate, an engagement member is integrally joined to the inner wall surface of the outer plate, and the flange is stacked on the inner wall surface of the outer plate in the engagement member A claw portion that can be locked with an extension is formed , and a convex portion that overshoots and bends at the protruding end of the step portion between the base portion joined to the outer plate of the engagement member and the claw portion is formed. It is characterized by that .
In this way, the claws can be attached to the inner wall surface of the outer plate via the silencer layer by engaging the flange with the flange on the inner wall surface of the outer plate. The flange of the outer plate is relatively displaceable with respect to the pawl on the outer plate side, so that the outer plate can be vibrated when it is vibrated, or it can be either thermally deformed by heating or cooling. Since there is no welded portion of the inner plate, the joint between the two plates is peeled off, deterioration over time due to corrosion can be eliminated, and the durability of the exhaust muffler can be improved. In particular, since the convex portion is formed at the protruding end of the step portion between the base portion and the claw portion, the supporting force of the claw portion that supports the flange can be maintained.
[0007]
According to a second aspect of the present invention, in the exhaust muffler according to the first aspect, the engaging member is formed with a through-hole communicating with the inside of the claw portion at a midway portion in the longitudinal direction .
In this case, even if exhaust gas condensate flows down to the inside of the claw of the engaging member when the muffler is cooled, it can be eliminated through the through-hole, and corrosion of the flange and the inside of the claw is suppressed, and the displacement operation of the same part is suppressed. It is possible to prevent obstruction and to prevent the corrosion inside the claw portion of the engaging member from proceeding. In this respect, the durability of the exhaust muffler can be improved.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show an exhaust muffler as an embodiment of the present invention. The exhaust muffler 1 has an inflow pipe 3 connected to an exhaust pipe 2 on the rear end side of a vehicle exhaust system E (not shown), reduces the pressure wave level of the inflowing exhaust gas, and passes the silenced exhaust gas through the outflow pipe 4 to the atmosphere side A. Configured to release.
As shown in FIG. 1, the exhaust muffler 1 is formed in a hollow shape inside the outer shell, and two expansion walls 7, 6 are arranged along the longitudinal direction X of the muffler so that three expansion chambers 7, 8, 9 are sequentially formed in series.
[0009]
The outer shell portion of the exhaust muffler 1 is formed by a rectangular cylindrical outer drum 11 and left and right end plates 12 and 13 that close both end openings in the muffler longitudinal direction X of the outer drum 11, and the whole is a vertically long rectangular box shape. Is made. From the left end plate 12 of the outer shell portion, a main attachment shaft 14 and an auxiliary attachment shaft 15 that attach the entire exhaust muffler to a vehicle body side base (not shown) protrude in parallel.
Glass wool 16 is laid on almost the entire area of the inner wall surface f1 of the outer drum 11, and is attached to the inner wall surface f1 by a punch plate 17 made of steel.
[0010]
Inside the outer shell is a first expansion chamber 7 between the left end plate 5 and the first partition 5, and a second expansion chamber 8 is connected between the first partition 5 and the second partition 6 on the right side of the second partition 6. A third expansion chamber 9 is formed in this order with the right end plate 13.
As shown in FIG. 2 (b), the first partition wall 5 has an inflow pipe 3, an outflow pipe 4, a main mounting shaft 14, and through holes h1, h2, h3 of first and second internal pipes 19 and 21, which will be described later. h4 and h5 are formed, and the outer peripheral edge is welded to the inner wall surface f1 of the outer drum 11. In addition, the 2nd partition 6 takes the structure substantially the same as a 1st partition, and abbreviate | omits duplication description.
[0011]
In the third expansion chamber 9, an inner opening 301 (the right opening side in FIG. 1) 301 of the inflow pipe 3 that passes through the left end plate 12 and the first second partition walls 5 and 6 sequentially opens. The outside opening of the inflow pipe 3 is connected to the exhaust pipe 2 via a joint 18 to guide the exhaust gas to the third expansion chamber 9. The inflow pipe 3 is welded so as to seal an annular gap that contacts the left end plate 12, closely contacts the annular curved flanges 501 and 601 formed in the first second partition walls 5 and 6, and one of the contact portions. The parts are welded.
[0012]
The inflow pipe 3 is formed with a short-circuit forming area B at each of the facing portions of the first and second expansion chambers 7 and 8, and the short-circuit forming area B is compared with the facing portion of the third expansion chamber 9. Formed large. The formation area B of each short circuit opening is formed by dispersing a number of pores (not shown) in an appropriate pattern. These formation areas B of the short-circuit ports function so as to diffuse the pressure wave of the exhaust gas flowing into the inflow pipe 3 in multiple stages.
The third expansion chamber 9 communicates with the first expansion chamber 7 via first and second internal pipes 19 and 21 that are arranged in parallel apart from the inflow pipe 3. The first and second inner pipes 19 and 21 are welded to the first second partition walls 5 and 6 at a plurality of locations. The first and second internal pipes 19 and 21 are both formed with a short-circuit opening forming region B at a portion facing the second expansion chamber 8, and exhaust gas from the third expansion chamber 9 is sent to the second and first expansion chambers 8 and 8. 7 to diffuse.
[0013]
In the second expansion chamber 8, an outflow pipe 4 that is arranged in parallel with a distance from the inflow pipe 3 is arranged oppositely. The outflow pipe 4 is formed with a short-circuit opening forming region B in almost the entire area facing the second expansion chamber 8, thereby communicating the second expansion chamber 8 with the opening on the outside air side A. The outflow pipe 4 is welded to the first second partition walls 5 and 6 at a plurality of locations, and the annular portion that contacts the left end plate 12 is sealed by continuous welding. In addition, the formation area B of each short circuit opening in the 1st, 2nd internal pipes 19 and 21 and the outflow pipe 4 is formed similarly to the case of the inflow pipe 3, and diffuses the pressure wave of the exhaust gas in multiple stages, respectively. To work.
Here, the left and right end plates 12 and 13 have substantially the same configuration, and the left end plate 13 has an inflow pipe 3, an outflow pipe 4, a main end, as shown in FIG. Each of the through holes h1, h2, h3 of the mounting shaft 14 is formed and the auxiliary mounting shaft 15 is welded. Here, the left end plate 12 will be mainly described.
[0014]
The left end plate 12 closes the left end of the outer drum 11 which is a cylindrical outer frame, and overlaps the rectangular outer plate 22 and its inner wall surface f2 as shown in FIGS. 1 and 2A. The glass wool silencer layer 23 to be laid, the inner plate 24 superposed on the outer plate so that the silencer layer 23 is pressed against the outer plate 22 side, and the inner wall f2 of the outer plate 22 are welded to the inner wall f2. And an engagement member 25 for attaching the plate 24 to the outer plate.
As shown in FIG. 4, the outer plate 22 is formed by a rectangular main portion 221 and a bent flange 222 that is bent and extended from the entire outer peripheral edge of the main portion. The main part 221 has a substantially flat plate shape, and the through-holes h1, h2, and h3 of the inflow pipe 3, the outflow pipe 4, and the main attachment shaft 14 are formed in the central part. The bent flange 222 is in contact with the inner peripheral surface of the left end edge of the outer drum 11 and is continuously welded to each other. Gas welding or arc welding is used for this welding, and welding is performed so as to maintain airtightness.
[0015]
The glass wool silencer layer 23 is formed so as to be laid over almost the entire inner wall surface f2 of the outer plate 22, and in particular, a layer capable of exhibiting a silencing function is employed.
The inner plate 24 presses the silencer layer 23 made of glass wool against the inner wall surface of the outer plate 22 without deviation, and is bent from the rectangular flat plate portion 241 that covers almost the entire inner wall surface f2 of the main portion 221 and the entire outer peripheral edge thereof. And a flange 243 that is further bent from the stepped part 242 and extends along the outer peripheral end of the inner wall surface f2 of the main part 221. The step width d (see FIG. 4) of the stepped portion 242 of the inner plate is formed to be slightly smaller than the bulkiness of the glass wool in the free state, and the glass wool can be pressurized.
[0016]
The extending portion of the flange 243 of the inner plate 24 is locked by two upper and lower engaging members 25 welded to the peripheral edge portion of the inner wall surface f2 of the main portion 221 of the outer plate. Each engaging member 25 has a base portion 251 spot welded to the main portion 221 of the outer plate and a claw portion 252 extending from the base portion and extending along the inner wall surface f2 in a state of being floated corresponding to the thickness of the flange of the inner plate. Formed with.
Here, the extension width g of the pawl portion 252 is formed to be approximately twice as wide as the contact width i when the inner plate is attached, so that the displacement on the inner plate 24 side when the flange 243 is engaged is allowed. Is formed.
The extension width g of the flange 243 of the inner plate 24 is set sufficiently larger than the clamping width i, thereby facilitating elastic displacement when the flange 243 is engaged with the pawl portion 252.
[0017]
Here, the engaging member 25 is formed in a straight shape, and the two upper and lower parts are used separately, but depending on the case, both may be formed long as a single unit or may be divided into three.
The exhaust muffler 1 shown in FIG. 1 operates to mute when high temperature exhaust gas flows in and exhausts exhaust gas. At that time, the outer shell portion expands and displaces, and when the exhaust gas inflow stops, the outer shell portion is cooled by the outside air and contracts and displaces.
[0018]
At this time, the inner plate 24 directly receives the exhaust gas and expands and contracts with respect to the outer plates 22 of the left and right end plates 12 and 13 that are part of the outer shell, and the expansion and contraction displacement of the both differ, It will be deformed. In particular, high-temperature and high-pressure exhaust gas flows directly into the third expansion chamber 9 from the inflow pipe 3, and the inner plate 24 of the right end plate 13 has a large thermal expansion. However, even if the inner plates 24 of the left and right end plates 12 and 13 are greatly displaced with respect to the outer plates 22, the outer plate and the inner plate here do not have a welded portion for joining them. Here, the flange 243 of the inner plate 24 is displaced relative to the claw portion 252 of the engaging member 25 on the outer plate side to absorb thermal deformation, and the inner plate and the outer plate are welded. It is possible to improve the durability of the exhaust muffler by eliminating the deterioration with time due to peeling and corrosion of the joint.
In the above description, the inner plate 24 has the left and right portions which are long in the vertical direction of the flange 243 formed in a straight shape. Instead, as shown in FIG. May be.
[0019]
In the inner plate 24a, the left and right portions of the flange 243 that are long in the vertical direction form a constricted portion J in the middle portion. In this case, the constricted portion J is formed such that its flange width k is smaller than that of the other portion k1. Therefore, when the entire flange 243 of the inner plate 24a is brought into contact with the inner wall surface f2 of the main portion 221 of the outer plate and is slid to be assembled, the constricted portion J is formed in the claw portion 252 of the upper and lower engaging members 25. If it is made to contact after holding so that it may oppose, the flange 243 part of the upper and lower one side can contact | abut to the nail | claw part 252 of the engaging member 25, and an assembly operation can be facilitated.
[0020]
As described above, the engaging member 25 has a saddle-shaped cross section as shown in FIG. 4, but instead of this, as shown in FIG. 6B, a stepped portion between the base 251a and the pawl 252a. A protruding portion r that overshoots and bends in the protruding direction is formed at the protruding end, and the elastic displacement of the pawl portion 252a is stabilized, so that the supporting force for supporting the flange 243 can be stably maintained. Also good.
In the above description, the engaging member 25 is disposed vertically, but may be disposed horizontally as indicated by a two-dot chain line in FIG.
[0021]
As shown in FIGS. 6A and 6B, when the engaging member 25a is disposed sideways, the condensate of the exhaust muffler tends to accumulate inside the claw portion 252a and the base portion 251a of the engaging member 25a. Therefore, a plurality of through-holes n communicating with the inside of the claw portion 252a may be formed in the middle of the longitudinal direction. When this through-hole n is formed, the condensate that has flowed into the inside of the claw portion 252a can easily flow down as indicated by an arrow, and corrosion of the flange 243 and the engaging member 25a is suppressed, and the displacement operation of the same portion is hindered. Can be prevented, and durability can be improved. In some cases, the through-holes can be formed in the same manner even in each of the vertical engagement members 25 in FIGS. 2A and 5, and the same effect can be obtained.
[0022]
In the above description, the outer shell of the exhaust muffler has a rectangular box shape. However, instead of this, a cylindrical exhaust muffler (the whole is not shown) may be used. In this case, the cylindrical exhaust muffler includes a circular end plate 12b. As shown in FIG. 7, the circular end plate 12b is formed by extending a stepped portion 242b at the peripheral edge of the disk-shaped inner plate 24b, and further bending from the protruding end thereof to form an annular flange 243b. Will be. Here, for example, the annular flange 243b is locked to the disk-shaped outer plate 22b side through three curved engagement members 25b at three locations in the circumferential direction. In this case, in order to avoid interference between the claw portion 252b of the curved engagement member 25b and the annular flange 243b at the time of assembling, three curved constricted portions Jb are formed on the annular flange 243b to facilitate the assembling. Other configurations are substantially the same as those of the exhaust muffler 1 of FIG. 1, and the same operational effects as the exhaust muffler 1 of FIG. 1 can be obtained.
[0023]
As described above, the exhaust muffler 1 is provided with the left and right end plates 12 and 13 for closing both end portions of the cylindrical outer shell body. May be simplified.
[0024]
【The invention's effect】
As described above, the present invention can attach the inner plate to the inner wall surface of the outer plate via the silencer layer by engaging the flange with the flange on the inner wall surface of the outer plate. At this time, the flange on the peripheral edge of the inner plate can be displaced relative to the pawl portion on the outer plate side, and either the inner plate is vibrated by being vibrated or thermally deformed by heating or cooling. Even if it occurs, since there is no welded portion between the outer plate and the inner plate, it is possible to eliminate deterioration over time due to cracks and corrosion around the joint between the two plates, and to improve the durability of the exhaust muffler. In particular, since the convex portion is formed at the protruding end of the step portion between the base portion and the claw portion, the supporting force of the claw portion that supports the flange can be maintained.
Furthermore, if a through-hole is formed in the longitudinal direction of the engaging member, even if the exhaust gas condensate flows down to the inside of the engaging member's claw when the muffler is cooled, this can be eliminated through the through-hole. In addition, it is possible to prevent corrosion inside the claw portion, prevent the displacement operation of the same portion from being hindered, and prevent corrosion inside the claw portion of the engaging member from progressing, and also in this respect, the durability of the exhaust muffler can be improved. .
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an exhaust muffler as an embodiment of the present invention.
2 shows components of the exhaust muffler of FIG. 1, in which (a) is an end plate and (b) is a first partition.
3 is a perspective view of an end plate of the exhaust muffler of FIG. 1. FIG.
4 is a cutaway cross-sectional view of the main part of the end plate in FIG. 1, and is a cross-sectional view taken along the line YY in FIG.
FIG. 5 is an enlarged front view of the end plate in FIG. 1;
6A and 6B show the engaging member in FIG. 1, in which FIG. 6A is a front view, and FIG.
FIG. 7 is a front view of a circular end plate used in an exhaust muffler according to another embodiment of the present invention.
8A and 8B show end plates used in a conventional exhaust muffler, where FIG. 8A is a cross-sectional view of a main part around one end plate, and FIG. 8B is a perspective view of another end plate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Exhaust muffler 11 Outer shell main body 12,13 End plate 12b Circular end plate 22 Outer plate 23 Sound deadening material layer 24 Inner plate 243 Flange 25 Engagement member 251 Base 252 Nail part Through hole r Convex part f2 Inner wall surface of outer plate

Claims (2)

In the exhaust muffler comprising an end plate that closes both ends of the cylindrical outer shell body, at least one of the outer plate and an inner plate attached to the inner wall surface of the outer plate via a sound deadening material layer,
A flange that extends from the periphery of the inner plate, an engagement member is integrally joined to the inner wall surface of the outer plate, and the engagement member is a pawl that can be locked with the flange overlapped on the inner wall surface of the outer plate. And a protruding portion that is bent by overshooting at the protruding end of the step portion between the base portion joined to the outer plate of the engaging member and the claw portion is formed. Exhaust muffler. The exhaust muffler according to claim 1,
The exhaust muffler according to claim 1, wherein the engaging member is formed with a through-hole communicating with the inside of the claw at an intermediate portion in the longitudinal direction .

Images