JP6700225B2 - Silencer - Google Patents

Description

  The present invention relates to a silencer.

  Conventionally, a silencer 101 as shown in FIGS. 14 and 15 is known as a silencer used for an exhaust system of an internal combustion engine. This silencer is referred to as Prior Art 1.

  This muffler 101 partitions the inner space of the casing 102 by an inner plate 103, and is divided into two muffling chambers, a first expansion chamber 104 and a second expansion chamber 105. The first expansion chamber 104 and the second expansion chamber are formed. 105 communicates with each other through a communication hole 106 formed of a plurality of punching holes formed in the inner plate 103.

  Further, an inlet pipe 107 into which exhaust gas discharged from the internal combustion engine is introduced is fixed through the casing 102 and the inner plate 103, and a downstream side opening end 107a of the inlet pipe 107 is opened in the first expansion chamber 104. ing. An outlet pipe 108 for discharging the exhaust gas in the silencer 101 to the outside is fixed through the casing 102 and the inner plate 103, and an upstream opening end 108a of the outlet pipe 108 is opened in the second expansion chamber 105. .

  Exhaust gas discharged from the internal combustion engine is silenced by flowing into the first expansion chamber 104 through the inlet pipe 107 and then into the second expansion chamber 105 through the communication hole 106 of the inner plate 103. After that, it is discharged to the outside through the outlet pipe 108.

  In the muffler 101, the exhaust gas flowing into the first expansion chamber 104 from the downstream opening end 107a of the inlet pipe 107 collides with the inner wall surface 102a of the casing 102 facing the downstream opening end 107a, and Due to the shape of parts near the downstream opening end 107a of the inlet pipe 107, the arrangement of the communication holes 106 of the inner plate 103, and the like, the pressure is biased toward the lower direction.

  As a result, as shown in FIG. 16, the exhaust gas becomes a main flow in the downward direction of FIGS. 15 and 16 in the first expansion chamber 104, and swirls in the lower portion of the first expansion chamber 104 in FIG. There is a problem that a flow is generated and the exhaust gas is disturbed in a portion flowing out to the second expansion chamber 105 through the communication hole 106 of the inner plate 103, causing airflow noise and increasing back pressure.

  Therefore, a conical projection is provided on the inner wall surface of the casing that faces the downstream opening end of the inlet pipe so that the apex thereof is located on the axis of the central axis of the inlet pipe to suppress the generation of spiral flow. There has been proposed a silencer configured to do so (see Patent Document 1). The silencer described in Patent Document 1 is referred to as Prior Art 2.

  Further, a convex portion projecting inward is formed on the inner wall surface of the casing that faces the downstream opening end portion of the inlet pipe, and the central portion of the convex portion has an axial core located on the axis of the central axis of the inlet pipe. There has been proposed a silencer in which a concave groove having a groove is formed to suppress the generation of a spiral flow (see Patent Document 2). The silencer described in Patent Document 2 is referred to as Prior Art 3.

JP-B-55-37692 Japanese Patent Publication No. 2-31209

  In the silencer of the related art 2 described above, the conical projection provided on the inner wall surface of the casing is provided such that the apex thereof is located on the same straight line as the axis of the inlet pipe. The exhaust gas cannot be uniformly diffused into the expansion chamber only by the radial projections, and it is difficult to solve the above problems.

  Like the silencer of the related art 2, the silencer of the related art 3 cannot evenly diffuse the exhaust gas into the expansion chamber, and it is difficult to solve the above problems.

  Then, this invention aims at proposing the silencer which solved the said problem.

In order to solve the above-mentioned problems, the present invention has a casing, and in the silencer, the inside of the casing is partitioned into a plurality of silencing chambers by an inner plate having a communication hole,
It has an inlet pipe and an outlet pipe,
In the muffler room where the downstream opening end formed in the inlet pipe is located , the inner peripheral surface of the portion facing the downstream opening end is provided with a convex portion projecting toward the downstream opening end,
The convex portion has a plurality of inclined surfaces that are inclined with respect to the central axis of the downstream opening end,
The apex on the side of the downstream opening end in the convex portion, with the ridge line on the inlet pipe side of the inclined surface, not provided on the axis of the central axis of the downstream side opening end,
The outlet pipe is open to a muffler chamber located upstream of the inlet pipe with respect to a muffler chamber where the downstream opening end of the inlet pipe is located.

  The areas of the plurality of inclined surfaces may be different from each other.

  INDUSTRIAL APPLICABILITY The present invention provides a convex portion projecting toward the downstream opening end portion at a portion facing the downstream opening end portion in a muffler room where the downstream opening end portion of the inlet pipe opens, and the top of the convex portion is provided. , The exhaust gas flowing into the muffling chamber from the downstream opening end of the inlet pipe hits the convex portion by not providing it on the axis of the central axis of the downstream opening end. It is scraped off and deflected, so that the exhaust gas can be uniformly diffused into the muffling chamber, the air flow noise can be reduced, and the back pressure can be reduced.

  Further, the convex portion has a plurality of inclined surfaces that are inclined with respect to the central axis of the downstream opening end, and the apex is the ridge line on the inlet pipe side of the inclined surface, so that the downstream opening of the inlet pipe is When the exhaust gas flowing into the muffling chamber from the end hits the convex part, the flow of the exhaust gas can be reliably separated and deflected, further reducing the air flow noise and reducing the back pressure. You can

  Also, by making the areas of the inclined surfaces of the convex portion different from each other, the deflection and flow velocity of the exhaust gas flow can be adjusted freely, further reducing airflow noise and reducing back pressure. can do.

1 is a vertical partial sectional view of a silencer according to a first embodiment of the present invention. Sectional view on the AA line of FIG. The side view of the convex part used for Example 1 of this invention. The figure seen from the protrusion side of FIG. FIG. 2 is a sectional view taken along line BB showing the flow of exhaust gas in the silencer of FIG. 1. FIG. 3 is a sectional view taken along the line C-C showing the flow of exhaust gas in the silencer of FIG. 2. The graph which shows the characteristic of the silencer of FIG. The side view of an example of the convex part used for Example 2 of the present invention. The side view of the other example of the convex part used for Example 2 of this invention. The figure which showed an example of the convex part used for Example 3 of this invention, and was seen from the protrusion side. The perspective view of an example of the convex part used for Example 4 of the present invention. The longitudinal cross-sectional view of the silencer according to the fifth embodiment of the present invention. The silencer which concerns on Example 6 of this invention, and sectional drawing equivalent to FIG. The longitudinal cross-sectional view of the silencer of the prior art 1. Sectional drawing of the DD line of FIG. FIG. 15 is a cross-sectional view taken along line EE showing the flow of exhaust gas in the silencer of FIG. 14. FIG. 15 is a cross-sectional view taken along line F-F showing the flow of exhaust gas in the silencer of FIG. 14.

  A mode for carrying out the present invention will be described based on an embodiment shown in the drawings.

[Example 1]
1 shows a vertical cross-sectional view of a silencer 1 according to a first embodiment of the present invention. As shown in FIG. 1, the muffler 1 has a casing 2 composed of a plurality of outer shell members, and a space 3 is formed in the casing 2.

  The space 3 of the casing 2 is partitioned by the inner plate 4 to divide and form two sound deadening chambers, a first expansion chamber 6 and a second expansion chamber 7, and a first expansion chamber 6 and a second expansion chamber 7 are formed. Are communicated with each other by a communication hole 8 formed of a plurality of punching holes formed in the inner plate 4.

  The inlet pipe 10 into which the exhaust gas discharged from the internal combustion engine is introduced is fixedly inserted through the insertion holes formed in the casing 2 and the inner plate 4 so that the inlet pipe 10 has both axial end portions opened. The downstream opening end 10a, which is an opening on the downstream side, is opened in the first expansion chamber 6. Further, the outlet pipe 11 for discharging the exhaust gas in the silencer 1 to the outside is fixedly inserted through the through holes formed in the casing 2 and the inner plate 4, and both axial ends thereof are opened. The upstream opening end 11 a, which is the opening on the upstream side, opens into the second expansion chamber 7.

  In the space 3, an inner wall surface 2a of the casing 2, which is a portion facing the downstream opening end portion 10a of the inlet pipe 10, is provided with a convex portion 15 formed by bending a metal plate and fixed by welding or the like. There is.

  As shown in FIGS. 3 and 4, the convex portion 15 is formed by bending a single rectangular flat plate made of metal. The convex portion 15 has a mutually different area, and has a planar first inclined surface 16 that is inclined with respect to the central axis XX of the downstream opening end portion 10 a of the inlet pipe 10, and a planar second inclined surface. 17 has two inclined surfaces, and the vertical end surface shape of the connecting portion between the end portion of the first inclined surface 16 on the inlet pipe 10 side and the end portion of the second inclined surface 17 on the inlet pipe 10 side is formed in an arc shape. Has been done. The surface area of the first inclined surface 16 is formed larger than the surface area of the second inclined surface 17, and the angle α1 of the first inclined surface 16 with respect to the mounting portion of the convex portion 15 on the inner wall surface 2a of the casing 2 is the second inclined surface. It is set smaller than the angle α2 of 17. Further, as shown in FIG. 1, the convex portion 15 is provided on the inner wall surface 2a such that the first inclined surface 16 is on the inlet pipe 10 side and the second inclined surface 17 is on the outlet pipe 11 side.

  Further, the ridge line (intersection line) 20 where the first inclined surface 16 and the second inclined surface 17 intersect, that is, the inclination direction of the inclined surface changes, is linear as shown in FIG. The ridge line 20 is formed so as to be in the lateral direction of the above, and the ridge line 20 constitutes the apex 21 of the convex portion 15 on the downstream opening end 10a side of the inlet pipe 10. The vertical end surface shape of the connecting portion between the first inclined surface 16 and the second inclined surface 17 may be formed to have an acute angle instead of the arc shape.

  The first sloping surface 16 and the second sloping surface 17 are formed such that their lengths in the ridgeline direction (Y-Y direction) are substantially the same in the entire direction orthogonal to the ridgeline (Z-Z direction). ing.

  Flanges 22 and 22 are formed on both sides of the convex portion 15, and the convex portion 15 is fixed to the inner wall surface 2a by fixing the flange 22 to the inner wall surface 2a of the casing 2 by welding or the like. . The flanges 22 may not be provided, and the edges of the inclined surfaces 16 and 17 may be fixed to the inner wall surface 2a by welding or the like.

  As shown in FIG. 2, the apex 21 of the convex portion 15 is located downstream of the apex 21 in the present embodiment so that the apex 21 is not located on the central axis X-X line at the downstream opening end 10 a of the inlet pipe 10. It is attached to the inner wall surface 2a so as to be located closer to the outlet pipe 11 than the central axis XX of the side opening end portion 10a.

  With the above structure, the exhaust gas discharged from the internal combustion engine passes through the inlet pipe 10 and flows into the first expansion chamber 6 from the downstream opening end 10a, and then passes through the communication hole 6 of the inner plate 4 to the second opening. The sound is silenced by flowing into the expansion chamber 7, and then discharged to the outside through the outlet pipe 11. At this time, the exhaust gas discharged from the downstream opening end 10a hits the convex portion 15.

  The apex 21 of the convex portion 15 is not located on the central axis X-X line in the downstream opening end portion 10a of the inlet pipe 10, and the two inclined surfaces 16 and 17 have the central axis X of the downstream opening end portion 10a. Due to the inclination with respect to -X and the inclination angles of the two inclined surfaces 16 and 17 being different, the exhaust gas hitting the convex portion 15 is scraped off and the flow thereof is deflected. As a result, as shown in FIG. 5 and FIG. 6, the upward flow on the opposite side of the outlet pipe 11 increases, which is small in the silencer 101 of the above-mentioned conventional technique 1. Further, since the swirl flow generated in the above-mentioned prior art 1 is reduced and the position of this swirl flow is moved away from the communication hole 8 of the inner plate 4, the exhaust gas is uniformly distributed in the first expansion chamber 6. It is diffused and smoothly flows out from the first expansion chamber 6 to the second expansion chamber 7. As a result, as shown in the graph of FIG. 7, it can be seen that the muffler 1 of the present invention has a lower air flow noise than the muffler 101 of the conventional technique 1 described above.

  Further, since the two inclined surfaces 16 and 17 of the convex portion 15 are configured so that their areas are different from each other, the deflection and flow velocity of the exhaust gas flow can be freely adjusted according to the configuration of the silencer 1. It is possible to optimize the flow of exhaust gas, reduce air flow noise, and reduce back pressure.

[Example 2]
In the first embodiment, the first inclined surface 16 and the second inclined surface 17 are each formed in a flat shape, but the first inclined surface 16 and the second inclined surface 17 are the downstream opening end of the inlet pipe 10. The two surfaces are formed so as to be inclined with respect to the central axis XX of 10a and located closer to the mounting portion side of the convex portion 15 on the inner wall surface 2a of the casing 2 as going from the apex 21 toward the outer side. If so, it can be formed in an arbitrary shape, for example, as shown in FIG. 8, the first inclined surface 16A is a curved surface that bulges toward the mounting portion of the convex portion 15 on the inner wall surface 2a of the casing 2. Alternatively, as shown in FIG. 9, the first inclined surface 16B may be a curved surface that bulges toward the inlet pipe 10.

  Further, the lengths of the first inclined surfaces 16, 16A, 16B and the second inclined surface 17 in the ridgeline direction (Y-Y direction) are substantially the same in the entire direction orthogonal to the ridgeline 20 (Z-Z direction). Is formed.

  The other structure is similar to that of the first embodiment, and the description thereof is omitted.

  Also in the second embodiment, the same effect as that of the first embodiment is obtained.

[Example 3]
In the first and second embodiments, the first inclined surfaces 16, 16A, 16B and the second inclined surface 17 of the convex portion 15 have a length in the ridgeline direction (Y-Y direction) in a direction orthogonal to the ridgeline 20. Although it is formed so as to be substantially the same in the entire (Z-Z direction), the length in the ridge line direction (Y-Y direction) is gradually increased or decreased in the middle in the direction (Z-Z direction) orthogonal to the ridge line 20. The convex portion 25 may be formed so as to change as described above.

  The length in the ridgeline direction (Y-Y direction) of the first inclined surfaces 16, 16A, 16B and the second inclined surface 17 of the convex portion 15 is, for example, as shown in FIG. 10, from one side (upper side of FIG. 10). The convex portion 25 may be formed by gradually narrowing toward the other side (downward in FIG. 10) at a constant rate.

  The other structures are the same as those in the first and second embodiments, and the description thereof will be omitted.

  The same effects as those of the first and second embodiments are also obtained in the third embodiment.

[Example 4]
In the first to third embodiments described above, the ridge line 20 of the convex portions 15 and 25 is formed in a linear shape, but it may be formed of a two-dimensional or three-dimensional curved line having an arbitrary shape. For example, as shown in FIG. 11, the intermediate portion in the ridgeline direction (Y-Y direction) may be a convex portion 35 that is a ridgeline 30 that is recessed toward the mounting portion side of the convex portion 35 with respect to the casing 2.

  The other structure is the same as that of the first to third embodiments, and the description thereof is omitted.

  The same effects as those of the first to third embodiments are also obtained in the fourth embodiment.

[Example 5]
In the above-mentioned Examples 1 to 4, the casing 2 and the convex portions 15, 25, 35 were formed by separate members, but as shown in FIG. 12, the casing 42 is deformed inward by press working or the like to form the convex portions. 45 may be formed integrally with the casing 42. The shape of the convex portion 45 is formed in the same manner as the convex portions 15, 25 and 35 of the above-described first to fourth embodiments.

  The other structures are the same as those in the first to fourth embodiments, and therefore the description thereof will be omitted.

  Also in the fifth embodiment, the same effects as those of the first to fourth embodiments are obtained.

[Example 6]
In the first to fifth embodiments, as shown in FIG. 2, the convex portions 15, 25, 35, and 45 have the direction (Z-Z direction) orthogonal to the ridgelines 20 and 30 as the vertical direction in FIG. However, the direction orthogonal to the ridgelines 20 and 30 (Z-Z direction) may be set to be an arbitrary direction with respect to the casing 2. For example, as shown in FIG. 13, the projections 15, 25, 35, 45 are arranged such that the direction (Z-Z direction) orthogonal to the ridgelines 20, 30 is inclined by an angle θ with respect to the vertical direction of FIG. It may be provided.

  The other structure is the same as that of the first to fifth embodiments, and the description thereof is omitted.

  Also in the sixth embodiment, the same effects as those of the first to fifth embodiments are obtained.

[Other Examples]
In the above Examples 1 to 6, the first inclined surfaces 16, 16A, 16B and the second inclined surface 17 are formed so as to have different areas, but they may have the same area.

  Further, in the above-mentioned Examples 1 to 6, the ridge lines 20 and 30 are formed so as to be one in the convex portions 15, 25, 35, and 45, but the convex portion is formed in a shape such as a pyramid shape, for example. Alternatively, a three-dimensional shape having a plurality of ridge lines may be used.

  In addition, in the above-described Examples 1 to 6, the convex portions 15, 25, 35, 45 are configured by the two inclined surfaces of the first inclined surfaces 16, 16A, 16B and the second inclined surface 17, but the inclined surfaces are It is sufficient that the number is plural, and the convex portion may be configured by three or more inclined surfaces.

  Moreover, in the said Examples 1-6, although the ridgelines 20 and 30 of the convex parts 15, 25, 35, and 45 were made into the peak 21 by the side of the downstream opening end part 10a, the convex part is spherical or conical. Alternatively, the apex on the downstream opening end 10a side may have no ridge line.

  The structure of the muffler is such that, in the muffler chamber in which the downstream opening end portion 1 of the inlet pipe is located, a convex portion protruding toward the downstream opening end portion is provided at a portion facing the downstream opening end portion. If the apex on the downstream opening end side of the inlet pipe in the convex portion is not provided on the axis of the central axis of the downstream opening end, it is not limited to Examples 1 to 6 and may be arbitrarily configured. For example, a resonance chamber may be provided, an inner pipe may be provided, or a plurality of inner plates may be provided.

1 silencer
6,7 Silencer room 10 Inlet pipe
10a Downstream side opening end part 11 Outlet pipe 15,25,35,45 Convex part 16,16A,16B,17 Inclined surface 20,30 Ridge line 21 Top

Claims (2)

A silencer having a casing, in which a plurality of silencing chambers are partitioned and formed by an inner plate having a communication hole,
It has an inlet pipe and an outlet pipe,
In the muffler room where the downstream opening end formed in the inlet pipe is located , the inner peripheral surface of the portion facing the downstream opening end is provided with a convex portion projecting toward the downstream opening end,
The convex portion has a plurality of inclined surfaces that are inclined with respect to the central axis of the downstream opening end,
The apex on the side of the downstream opening end in the convex portion, with the ridge line on the inlet pipe side of the inclined surface, not provided on the axis of the central axis of the downstream side opening end,
The silencer is characterized in that the outlet pipe opens into a silencing chamber located upstream of the inlet pipe with respect to the silencing chamber where the downstream opening end portion of the inlet pipe is located .   The silencer according to claim 1, wherein the plurality of inclined surfaces have different areas.