JP6450050B2 - Muffler - Google Patents

Description

  The present disclosure relates to a muffler configured to reduce exhaust noise.

  The following cited document 1 discloses a technique for facilitating the discharge of water accumulated in the muffler by arranging the muffler in an inclined manner.

JP 2009-092033 A

In order to arrange the muffler in an inclined manner, there is a problem that a space for arranging the muffler becomes large.
In one aspect of the present disclosure, it is desirable that the muffler can be drained well without the muffler being inclined.

  A muffler according to one aspect of the present disclosure includes a housing, an exhaust introduction unit, and an exhaust discharge unit. The housing is configured to have a space inside. The exhaust introduction unit is configured to introduce exhaust into the housing. The exhaust discharge part is configured in a tubular shape, and is configured to discharge the exhaust in the casing by allowing the exhaust in the casing to flow into the exhaust.

  In addition, the exhaust discharge portion has an exhaust inlet portion that is configured to open and serve as an exhaust inlet. The exhaust inlet portion is disposed so that the tangential direction extending along the rotation direction among the tangent lines in the virtual circle coincides with the exhaust direction in which the exhaust proceeds at the exhaust inlet portion.

  However, the virtual circle represents a virtual circle of an arbitrary size centered on the center of gravity of the space when the space in the housing is viewed along the vertical direction in the vehicle mounted state. In addition, the rotation direction is a virtual circle on the exhaust introduction portion side of a portion on an arc having a tangent line parallel to the introduction direction representing the direction when the exhaust introduced from the exhaust introduction portion linearly travels. It represents a direction that coincides with the introduction direction at a certain site.

  According to such a muffler, since the exhaust inlet portion is arranged so that the rotation direction and the exhaust flow direction at the exhaust inlet portion coincide with each other, an exhaust vortex can be generated in the casing. And since the water in a muffler can be moved by this vortex, it can be made easy to discharge from an exhaust discharge part.

In the muffler, the housing may further include a protruding portion that protrudes upward from the bottom surface in the vicinity of the exhaust inlet portion on the bottom surface of the housing.
According to such a muffler, the water level in the vicinity of the exhaust inlet portion can be increased by the protruding portion, so that the water can be easily drained from the exhaust inlet portion.

Further, in the muffler, the projecting portion may be disposed at a position outside the virtual circle with respect to the exhaust inlet portion.
According to such a muffler, the protrusion blocks the water that tends to move to the outer edge side of the casing by the exhaust vortex generated in the casing. Can be raised. Therefore, it can be made easy to drain from the exhaust inlet.

Further, in the muffler, the housing may further include an annular low bottom portion having a bottom surface lower than the other parts and configured around the center of gravity.
According to such a muffler, water can be collected at the bottom and moved by the vortex of the exhaust. Therefore, since water can be moved to the vicinity of the exhaust inlet portion, it can be easily drained from the exhaust inlet portion.

  The muffler further includes a separator that partitions the space inside the housing into at least an upper space and a lower space located below the upper space when the muffler is used. The separator includes the upper space and the lower space. You may comprise so that it may have a ventilation part which connects a side space.

According to such a muffler, since the separator is disposed between the exhaust introduction part and the exhaust discharge part, the silencing effect can be improved.
Further, in the muffler, the exhaust discharge portion may be configured to approach the bottom surface of the casing as it goes toward the exhaust inlet portion.

  According to such a muffler, the exhaust inlet portion is brought close to the bottom surface of the housing, so that water can be easily sucked from the exhaust inlet portion.

It is a perspective view of the muffler in an embodiment. It is a disassembled perspective view of the muffler in an embodiment. It is a top view of the lower muffler shell in an embodiment. It is IV-IV sectional drawing of the lower muffler shell in embodiment. It is VV sectional drawing of the lower muffler shell in embodiment. 3 is a plan view showing a positional relationship between an exhaust inlet 13A and an exhaust inlet portion 21 in the embodiment. FIG. It is a VII-VII sectional view of a muffler in an embodiment. It is sectional drawing of the lower muffler shell in other embodiment. It is a top view of the lower muffler shell in other embodiments. It is XX sectional drawing of the lower muffler shell in other embodiment. FIG. 10 is a plan view showing a positional relationship between an exhaust inlet 13A and an exhaust inlet portion 21 in still another embodiment. FIG. 10 is a plan view showing a positional relationship between an exhaust inlet 13A and an exhaust inlet portion 21 in still another embodiment. FIG. 10 is a plan view showing a positional relationship between an exhaust inlet 13A and an exhaust inlet portion 21 in still another embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Muffler, 2 ... Exhaust path, 10 ... Housing, 10A ... Upper space, 10B ... Lower space, 10C ... Gap part, 11, 12 ... Muffler shell, 12A ... Close contact part, 13, 14 ... Outer plate, 13A ... Inlet, 14A ... outlet, 15 ... peripheral step, 16 ... center step, 17 ... low bottom, 18A, 18B, 18C ... projection, 19 ... water level, 20 ... separator, 21 ... exhaust inlet, 21A ... notch , 23 ... Left edge part, 24 ... Front edge part, 25 ... Right edge part, 26 ... Rear edge part, 27 ... Vent hole, 28 ... Recessed part, 29 ... Lower part, 30 ... Upper plate, 31 ... Hole part, 40 ... Sound absorbing material, 50 ... Cover pipe, 72 ... Virtual circle, 73 ... Water flow.

Hereinafter, an example of an embodiment of the present disclosure will be described with reference to the drawings.
[1. Embodiment]
[1-1. Constitution]
The muffler of the embodiment discharges exhaust from an internal combustion engine of an automobile to the outside of the host vehicle, and is configured as a device that reduces exhaust noise. The own vehicle refers to a vehicle equipped with the muffler of the present disclosure. Hereinafter, in a vehicle mounted state representing a state where the muffler is mounted on the host vehicle, the front side and the rear side of the host vehicle are referred to as front and rear, respectively, and the right side and the left side toward the rear of the host vehicle are set to right and left, respectively. Called. Further, the vertical direction and the vertical direction also indicate directions in a state where the muffler is mounted on the host vehicle.

  As shown in FIGS. 1 and 2, the muffler 1 is formed in a columnar shape having a substantially elliptical side surface, and an exhaust path 2 is formed inside. The exhaust path 2 is formed as a tube in which the exhaust path extends in a J-shape.

  The muffler 1 includes a housing 10 that covers the outside of the muffler 1, a separator 20, an upper plate 30, a sound absorbing material 40, a cover pipe 50, and the like that are disposed in the internal space of the housing 10. These parts excluding the sound absorbing material 40 are made of stainless steel as an example, but are not limited to this, and may be made of another material having heat resistance.

  The housing 10 includes muffler shells 11 and 12, outer plates 13 and 14, and the like, and these are formed by press molding. In FIG. 1 and FIG. 2, the detailed configuration of the lower muffler shell 12 is omitted. Further, in FIG. 2, a part of a vent hole 27 in the separator 20 described later is omitted. An arbitrary number of the vent holes 27 can be arranged at an arbitrary position.

  The outer plates 13 and 14 are horizontally long and substantially elliptical plate-like members, and are arranged in a state of facing in the front-rear direction. The front outer plate 13 has an inlet 13 </ b> A for introducing exhaust gas at a position slightly to the left of the upper center in the vertical direction. The outer edge of the outer plate 13 has an L-shaped cross section.

  Exhaust gas is introduced into the upper space 10A described later from the inlet 13A. Further, the rear outer plate 14 has an exhaust outlet 14A formed at a position on the left side in the center in the vertical direction. Further, the outer edge of the outer plate 14 has an L-shaped cross section.

  The muffler shells 11 and 12 are rectangular plate-like members curved in a horizontally long U shape, and are arranged in a state of facing in the vertical direction. Of course, the shape of the muffler shells 11 and 12 is not limited to this, and may be various shapes.

  The separator 20, the upper plate 30, and the cover pipe 50 are also plate-like members formed by press molding. The muffler shells 11 and 12, the separator 20, the upper plate 30, the sound absorbing material 40, and the cover pipe 50 are arranged in a state where they are stacked in the vertical direction.

As shown in FIG. 2, the separator 20 includes a notch 21 </ b> A, a left edge 23, a front edge 24, a right edge 25, a rear edge 26, a vent hole 27, and a recess 28. .
As shown in FIG. 1, the separator 20 is arranged so as to divide the internal space of the housing 10 into two vertically. In other words, the separator 20 is disposed so as to cover the entire cross section of the internal space. Hereinafter, the upper side of the separator 20 in the internal space is referred to as an upper space 10A, and the lower side is referred to as a lower space 10B.

  The left edge portion 23, the front edge portion 24, and the rear edge portion 26 are portions formed by bending the outer edge of the separator 20 upward in an L shape. The right edge portion 25 is a portion formed by bending the outer edge of the separator 20 downward in an L shape. The left edge portion 23 is joined to the muffler shells 11 and 12 to constitute the contact portion 12A. Further, the right edge portion 25 is joined to the muffler shells 11 and 12 to constitute the contact portion 12B.

  The contact portion 12A shows a portion where the left edge portion 23 and the muffler shells 11 and 12 are in close contact with each other, and the contact portion 12B is in a state where the right edge portion 25 and the muffler shells 11 and 12 are in close contact with each other. Indicates the site. A gap 10C is formed between the front edge 24 and the outer plate 13 as a gap due to not being in close contact, and a gap is defined as a gap due to not being in close contact between the rear edge 26 and the outer plate 14. Part 10D is configured.

  The recess 28 is formed in a shape that has a U-shaped cross section and protrudes downward by deforming a part of the separator 20. The recess 28 forms a J-shaped path, and extends from the starting point, which is a position slightly rearward on the right side of the separator 20, to the edge on the left rear side of the separator 20 through the front center.

  The cutout portion 21A is formed by cutting out the vicinity of the starting point of the recess 28 into a substantially rectangular shape. The boundary between the notch 21 </ b> A and the recess 28 serves as the exhaust inlet 21. The exhaust inlet 21 serves as an inlet for exhaust from the space in the housing 10 to the exhaust path 2.

  The ventilation hole 27 is a ventilation hole. A large number of vent holes 27 are formed on the separator 20. The large number of vent holes 27 and the above-described gap portion 10C are configured to communicate the upper space 10A and the lower space 10B.

  As shown in FIG. 2, the upper plate 30 has a hat-shaped cross section, in other words, an inverted U shape, and is formed as an inner surface groove-shaped member whose outer surface protrudes upward. The upper plate 30 forms a J-shaped path similar to the concave portion 28 of the separator 20, and is arranged in a state of facing the concave portion 28. A large number of small-diameter holes 31 are formed in the upper plate 30.

  The cover pipe 50 is a hat-shaped cross section similar to the cross section of the upper plate 30, and is formed as an inner groove-shaped member whose outer surface protrudes upward. The cover pipe 50 forms a J-shaped path similar to the recess 28 of the separator 20 and the upper plate 30. The cover pipe 50 is disposed so as to cover the upper plate 30 from above with a gap formed between the cover pipe 50 and the upper plate 30. That is, the cover pipe 50 is arranged in a state of facing the concave portion 28 of the separator 20 located below the upper plate 30. Further, in the gap between the cover pipe 50 and the upper plate 30, for example, a sound absorbing material 40 configured as glass wool is disposed. The sound absorbing material 40 may be configured as a metal fiber such as stainless steel, for example. The sound absorbing material 40 is arranged in a state of being sandwiched between the cover pipe 50 and the upper plate 30.

  Further, the gap between the recess 28 of the separator 20 and the cover pipe 50 becomes the exhaust path 2. The exhaust path 2 is a J-shaped path starting from the exhaust inlet 21 formed in the separator 20 and ending at the outlet 14A of the rear outer plate 14. That is, the outlet 14 </ b> A, the exhaust inlet portion 21, the recess 28, and the cover pipe 50 constitute a tubular exhaust path 2.

  Here, the exhaust gas of the internal combustion engine contains a lot of moisture, and a lot of water droplets are generated by the condensation of the moisture. In the muffler 1, since there is a possibility that many water droplets are accumulated in the muffler shell 12, a device for facilitating discharging such water droplets from the exhaust path 2 is taken.

  3, 4, and 5, the lower muffler shell 12 has a relative position at the four corners and a portion near the center including a position (center O described later) serving as the center of gravity in the plan view of the muffler shell 12. Configured to be higher. In other words, the lower muffler shell 12 is provided with a plurality of peripheral step portions 15 configured to be higher at the four corners at the four corners. In addition, a central step portion 16 configured in an annular shape is provided in the vicinity of the center of the lower muffler shell 12 so that a portion near the center is higher than the periphery thereof.

  With this configuration, the low bottom portion 17 is formed. The low bottom portion 17 is an annular portion that is configured to be lower than other portions around the center of gravity in the plan view of the muffler shell 12. Since the low bottom part 17 is a relatively low position in the muffler shell 12, the water in the housing 10 is collected. For this reason, compared with the structure which is not provided with the peripheral level | step-difference part 15 and the center level | step-difference part 16, the low bottom part 17 has a function which raises the water level 19 in the low bottom part 17. FIG.

  Further, as shown in FIG. 6, the exhaust inlet 21 has a direction of a tangent line (in FIG. 6) extending along a rotation direction (arrow B in FIG. 6) among arbitrary tangent lines in an imaginary circle 72 having an arbitrary diameter. An arrow C) and the exhaust direction (arrow D in FIG. 6) in which exhaust proceeds at the exhaust inlet 21 are arranged to coincide. However, the virtual circle 72 represents a virtual circle of an arbitrary size centered on the center of gravity of the space when the space in the housing 10 is viewed along the vertical direction. Further, the rotation direction (arrow B in FIG. 6) is a tangent parallel to the introduction direction (arrow A in FIG. 6) indicating the direction in which the exhaust gas introduced from the inlet 13A travels linearly in the virtual circle 72. Of the parts (P1, P2) on the circular arc having a portion, the part (P1) on the inlet 13A side represents the direction that coincides with the introduction direction.

  In the present embodiment, at a point Q on the arc, a direction (arrow C in FIG. 6) coinciding with the rotation direction in the tangential direction, and an exhaust direction in which exhaust proceeds at the exhaust inlet portion 21 (arrow D in FIG. 6). And the position of the exhaust inlet 21 are set so as to match. In the present embodiment, P2 and Q match.

  When the exhaust inlet 13 </ b> A and the exhaust inlet 21 serving as the exhaust outlet are arranged in this manner, an exhaust vortex rotating along the rotation direction of the virtual circle 72 is generated in the housing 10. Due to the flow of the vortex, water accumulated in the low bottom portion 17 of the muffler shell 12 is caused to flow in the same direction as the rotation of the vortex.

  In addition, the low bottom portion 17 of the muffler shell 12 is provided with a protruding portion 18A as shown in FIGS. The protruding portion 18A is configured to protrude upward from the low bottom portion 17 in the vicinity of the exhaust inlet portion 21, and in the present embodiment, the cross section is in the shape of each side of an isosceles triangle in an isosceles triangle. . In addition, the vicinity of the exhaust inlet 21 means that the water level rises around the protrusion 18 </ b> A due to water getting on the protrusion 18 </ b> A or being blocked by the presence of the protrusion 18 </ b> A. The water is located within a range where water is easily sucked into the exhaust inlet 21.

  Moreover, the recessed part 28 which comprises the exhaust path 2 is provided with the falling part 29, as shown in FIG. The descending portion 29 is a portion that is configured to expand downward so as to approach the bottom surface of the housing 10 toward the exhaust inlet portion 21 side in the concave portion 28.

  With such a configuration, the water accumulated in the low bottom portion 17 of the muffler shell 12 is caused to flow by the vortex of the exhaust, and the water level 19 rises in the vicinity of the exhaust inlet 21 due to the presence of the protrusion 18A.

  Further, since the exhaust inlet portion 21 is brought closer to the bottom surface of the housing 10 by the lowered portion 29, the water accumulated in the low bottom portion 17 of the muffler shell 12 is satisfactorily sucked into the exhaust inlet portion 21.

  The exhaust gas that has entered the muffler 1 from the inlet 13A flows into the upper space 10A and moves from the vent hole 27 and the gap 10C provided in the separator 20 to the lower space 10B while drawing a vortex in the upper space 10A. . The exhaust enters the exhaust path 2 from the exhaust inlet 21 of the separator 20 while drawing a vortex in the lower space 10B, passes through the exhaust path 2, and is discharged to the outside of the housing 10 from the outlet 14A. . The exhaust path 2 only needs to be configured to allow exhaust to enter from a region including the lower space 10B, and may also allow exhaust to enter from the upper space 10A.

Exhaust gas flowing through the exhaust path 2 passes through the hole 31 of the upper plate 30 and contacts the sound absorbing material 40. Thereby, exhaust noise is suppressed.
[1-2. effect]
According to the first embodiment described in detail above, the following effects are obtained.

  (1a) The muffler 1 of the above embodiment includes a housing 10, an inlet 13A, and an exhaust path 2. The housing 10 is configured to have a space inside. The inlet 13A is configured to introduce exhaust into the housing 10. The exhaust path 2 is configured in a tubular shape, and is configured to discharge the exhaust in the housing 10 by causing the exhaust in the housing 10 to flow into the exhaust inlet 21.

  In addition, the exhaust path 2 has an exhaust inlet portion 21 that is open and configured to be an exhaust inlet. The exhaust inlet portion 21 is arranged so that the direction of a tangent extending along the rotation direction among arbitrary tangents in the virtual circle coincides with the exhaust direction in which the exhaust proceeds at the exhaust inlet portion 21.

  However, the virtual circle represents a virtual circle of an arbitrary size centered on the center of gravity of the space when the space in the housing 10 is viewed along the vertical direction. Further, the rotation direction is a portion on the inlet 13A side of a portion on a circular arc having a tangent line parallel to the introduction direction representing the direction when the exhaust gas introduced from the inlet 13A travels linearly in a virtual circle. Represents a direction coinciding with the introduction direction.

  According to such a muffler 1, the exhaust inlet portion 21 is arranged so that the rotation direction and the exhaust flow direction at the exhaust inlet portion 21 coincide with each other, so that an exhaust vortex can be generated in the housing 10. it can. And since the water in the muffler 1 can be moved by this vortex, it can be made easy to discharge from the exhaust path 2.

(1b) In the muffler 1 of the above embodiment, the housing 10 further includes a protruding portion 18A that protrudes upward from the bottom surface in the vicinity of the exhaust inlet portion 21 on the bottom surface of the housing 10.
According to such a muffler 1, the water level in the vicinity of the exhaust inlet portion 21 can be increased by the protrusions 18 </ b> A, 18 </ b> B, and 18 </ b> C, so that drainage from the exhaust inlet portion 21 can be facilitated.

(1c) The muffler 1 of the above embodiment further includes an annular low bottom portion 17 configured such that the bottom surface of the housing 10 has a lower height than the other parts around the center of gravity.
According to such a muffler 1, water can be collected in the low bottom part 17 and the water can be moved by the vortex of exhaust. Therefore, since water can be moved to the vicinity of the exhaust inlet 21, it can be easily drained from the exhaust inlet 21.

  (1d) The muffler 1 of the above embodiment further includes a separator 20 that partitions the space inside the housing 10 into at least an upper space 10A and a lower space 10B located below the upper space 10A. 13A is configured to introduce exhaust into the upper space 10A, the exhaust path 2 is configured to exhaust exhaust from a region including the lower space 10B, and the separator 20 includes a large number of gaps 10C, vent holes 27.

  According to such a muffler 1, since the separator 20 is disposed between the inlet 13 </ b> A and the exhaust path 2, the silencing effect can be improved. Further, since this separator 20 has a large number of gaps 10C and vent holes 27, it is possible to easily form exhaust vortices in the upper space 10A and the lower space 10B even in the structure having the separator 20. . Therefore, drainage from the exhaust inlet 21 can be facilitated.

(1e) In the muffler 1 of the above-described embodiment, the exhaust path 2 is configured to approach the bottom surface of the housing 10 toward the exhaust inlet 21 side.
According to such a muffler 1, the exhaust inlet 21 is brought close to the bottom surface of the housing 10, so that water can be easily sucked from the exhaust inlet 21.

[2. Other Embodiments]
As mentioned above, although embodiment of this indication was described, this indication is not limited to the above-mentioned embodiment, and can carry out various modifications.

  (2a) In the above-described embodiment, the projecting portion 18A is configured to have an isosceles triangle shape, but is not limited thereto. For example, it is good also as the protrusion part 18B as shown in FIG. One end of the projecting portion 18 </ b> B is configured to be perpendicular to the low bottom portion 17 of the muffler shell 12 in the cross section.

  (2c) Moreover, like the protrusion part 18C shown in FIG. 9, you may arrange | position in the position which becomes the outer peripheral side of the virtual circle 72 rather than the exhaust inlet part 21. FIG. That is, the protruding portion 18 </ b> C may be disposed at a position closer to the side wall of the housing 10 than the position of the exhaust inlet portion 21.

  At this time, an arbitrary shape can be adopted as the cross-sectional shape of the protruding portion 18C. For example, as shown in FIG. 10, the cross-sectional shape of the protruding portion 18C is configured so that both ends are perpendicular to the low bottom portion 17 of the muffler shell 12. Also good. When the projecting portion 18C is arranged in this manner, as shown in FIG. 9, when the water flow 73 is generated according to the flow of the vortex, the water level 19 inside the vortex projects from the projecting portion 18C as shown in FIG. It can be made higher than the water level 19 outside the vortex than the portion 18C. Therefore, since the water level 19 can be brought close to the exhaust inlet 21, water can be easily sucked from the exhaust inlet 21.

  (2d) In the above-described embodiment, the exhaust inlet 13A and the exhaust inlet portion 21 are arranged at positions generally spaced from the exhaust vortex, but the present invention is not limited to this. The exhaust inlet 21 may be arranged so that the direction of the tangent extending along the rotation direction among arbitrary tangents in the virtual circle coincides with the exhaust direction in which the exhaust proceeds at the exhaust inlet 21.

  For example, as shown in FIG. 11, the exhaust inlet 13 </ b> A and the exhaust inlet 21 may be arranged side by side at a certain distance on the same side wall of the housing 10. In addition, as shown in FIG. 12, the exhaust inlet 13 </ b> A and the exhaust inlet portion 21 may be disposed at opposing positions on the opposite sidewalls of the housing 10. Further, as shown in FIG. 13, the exhaust inlet 13A may be disposed on the rear side of the left side surface, and the exhaust inlet portion 21 may be disposed on the right side of the front side surface.

Even in these cases, the same effect as the above (1a) can be obtained.
(2e) In the above embodiment, the exhaust introduction portion of the present disclosure is configured as the inlet 13 </ b> A provided in the housing 10. However, any configuration may be used as long as the exhaust is guided to the housing 10. For example, a cylindrical member such as an inlet pipe may be applied as the exhaust introduction part. Similarly, a cylindrical member such as an outlet pipe may be applied as the exhaust discharge portion.

  (2f) A plurality of functions of one constituent element in the above embodiment may be realized by a plurality of constituent elements, or a single function of one constituent element may be realized by a plurality of constituent elements. . Further, a plurality of functions possessed by a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element.

  Moreover, you may abbreviate | omit a part of structure of the said embodiment. Further, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

(2g) In addition to the muffler 1 described above, the present disclosure can be realized in various forms such as a system including the muffler 1 as a constituent element.
[3. Correspondence between Configuration of Embodiment and Configuration of Present Disclosure]
In the above embodiment, the inlet 13A corresponds to an example of the exhaust introduction part referred to in the present disclosure. In the above embodiment, the outlet 14A, the exhaust inlet part 21, the recess 28, and the cover pipe 50 correspond to an example of the exhaust discharge part referred to in the present disclosure. To do. In the above embodiment, the vent hole 27 and the gap portion 10C correspond to an example of the vent portion in the present disclosure.

Claims (6)

A housing configured to have a space inside;
An exhaust introduction section configured to introduce exhaust into the housing;
An exhaust discharge portion configured to discharge the exhaust in the casing by flowing the exhaust in the casing into the tube; and
With
The exhaust discharge part has an exhaust inlet part that is configured to open and serve as an exhaust inlet,
A virtual circle of any size centered on the center of gravity of the space when the space in the housing is viewed along the vertical direction in the vehicle mounted state,
In the virtual circle, at a portion on the exhaust introduction portion side of a portion on an arc having a tangent line parallel to the introduction direction representing the direction in which the exhaust gas introduced from the exhaust introduction portion linearly travels , The direction coinciding with the introduction direction as a rotation direction in the virtual circle,
The exhaust inlet portion is arranged such that a tangential direction extending along the rotation direction among tangents in the virtual circle and an exhaust direction in which exhaust proceeds at the exhaust inlet portion are aligned with each other ,
The casing has an annular low bottom portion that is configured around the center of gravity, the height of the bottom surface of the casing being lower than other parts,
A muffler further equipped . The muffler according to claim 1,
The housing is a bottom surface of the housing and protrudes upward from the bottom surface in the vicinity of the exhaust inlet portion;
A muffler further equipped. The muffler according to claim 2,
The muffler configured so that the protruding portion is disposed at a position outside the virtual circle with respect to the exhaust inlet portion. The muffler according to claim 2 or claim 3 ,
The protrusion is disposed at the low bottom.
A muffler configured as follows . The muffler according to any one of claims 1 to 4,
A separator that partitions the space inside the housing into at least an upper space, and a lower space located below the upper space;
Further comprising
The muffler configured so that the separator has a ventilation portion that communicates the upper space and the lower space. The muffler according to any one of claims 1 to 5,
The muffler configured such that the exhaust discharge portion approaches the bottom surface of the housing as it goes toward the exhaust inlet portion.