WO2022210876A1

WO2022210876A1 - Muffler apparatus

Info

Publication number: WO2022210876A1
Application number: PCT/JP2022/015982
Authority: WO
Inventors: ジェッサダーミンデーン; ポンパットケハーバーン
Original assignee: 本田技研工業株式会社
Priority date: 2021-03-31
Filing date: 2022-03-30
Publication date: 2022-10-06
Also published as: BR112023019839A2; JPWO2022210876A1

Abstract

The present invention provides a muffler apparatus provided in a saddle-type vehicle with which turbulent flow near the exhaust port of a tailpipe can be prevented from occurring to achieve a favorable exhaust flow and eliminate the impact on driving performance, and in which the man-hours for molding and assembly of the tailpipe and a muffler cover are reduced.　In a muffler apparatus 7 having a muffler body 70 connected to the rearward end 55a of an exhaust pipe 55 of an internal combustion engine 3 of a saddle-type vehicle 1, a tail pipe 74 with an exhaust port 74a protruding rearward is provided at the rear of the muffler body 70, a muffler cover 8 separated from the muffler body is provided around the exhaust port, a gap 81 through which a relative wind is introduced between the muffler cover and the muffler body is provided, and an introduced wind guide part 84 that guides the relative wind introduced from the gap to the side with respect to the exhaust port.

Description

muffler device

The present invention relates to a muffler device provided in a straddle-type vehicle.

In general, the muffler device of a saddle-ride type vehicle is equipped with a muffler cover, but the running wind that flows around the muffler cover is caught in the rear end of the muffler cover and generates turbulence, which may affect the exhaust performance. .
On the other hand, a muffler cover is provided with an intake port, the exhaust outlet side of the tail pipe of the muffler body is bent toward the side, and the running wind from the intake port is applied to promote exhaust, for example, Patent Document 1 below. However, the molding and combination of the tail pipe and the muffler cover require a lot of man-hours, and the muffler body and the muffler cover are integrally constructed, which poses a problem of weight reduction and cost reduction.
Further, a muffler cover provided with a gap between the muffler body and the rear end of the muffler body to take in the running wind is disclosed in, for example, Patent Document 2 below. and interferes with the exhaust at the exhaust outlet of the tail pipe, affecting the exhaust.

Japanese Patent Application Laid-Open No. 2006-017046 (Figs. 3 to 8) Japanese Patent Application Laid-Open No. 2009-264293 (Fig. 2, Figs. 7 to 9)

The present invention has been made in view of the above prior art, and is a muffler device provided in a straddle-type vehicle that prevents turbulence from occurring in the vicinity of the exhaust outlet of the tail pipe and improves the exhaust flow, thereby improving the running performance. To provide a muffler device capable of eliminating the influence on a tail pipe and a muffler cover and reducing man-hours for molding and combining a tail pipe and a muffler cover.

In order to solve the above problems, the present invention
A muffler device having a muffler body connected to a rear end portion of an exhaust pipe of an internal combustion engine of a straddle-type vehicle,
A tail pipe with an exhaust outlet protruding rearward is provided at the rear part of the muffler body, and a muffler cover spaced from the muffler body is provided around the exhaust outlet, and the muffler cover and the muffler body are provided. A gap is provided for introducing running wind, and an introduction wind guide part is provided for guiding the running wind introduced through the gap to the side of the exhaust outlet with respect to the exhaust outlet. It is a muffler device that

According to the above configuration,
By providing an introduction wind guide section that guides the running wind to the side of the exhaust outlet, the running wind is prevented from hitting the vicinity of the exhaust outlet and the occurrence of turbulence in the vicinity of the exhaust outlet is prevented. can be prevented, the exhaust flow can be improved, and the influence on the running performance can be eliminated.
In addition, the exhaust outlet of the tail pipe is oriented rearward, which reduces the man-hours for molding and combining the tail pipe and the muffler cover.

According to a preferred embodiment of the invention,
The muffler cover has an airflow guide hole opening rearward away from the exhaust outlet in the vehicle outer side portion of the rear portion thereof, and the airflow guide portion is provided inside the muffler cover to the exhaust outlet. and the introduction air guide hole, and erected in parallel to the discharge direction of the exhaust gas discharged from the exhaust outlet.
Therefore, the running wind introduced into the muffler cover can be discharged by the leading wind guide part without hitting the exhaust gas into the leading wind guide hole, and the introduced running wind can be discharged without hitting the exhaust gas. By guiding in the direction parallel to the discharge direction, a curtain of running wind can be created in the direction parallel to the exhaust gas discharge direction, so it is possible to prevent the running wind from being drawn into the muffler cover from the outer side of the vehicle.

According to a preferred embodiment of the invention,
The muffler cover is a tail cap that covers the entire rear end of the muffler body.
Since the muffler cover functions as a tail cap and covers the entire rear end portion of the muffler body, it is possible to protect surrounding people from the heat of the rear end portion of the muffler body.

According to a preferred embodiment of the invention,
The muffler cover is made of resin.
By making the muffler cover made of resin, it is possible to reduce weight and cost, and to reduce the generation of radiant heat.

According to a preferred embodiment of the invention,
The muffler device includes a second muffler cover that covers the outer surface of the muffler main body and has a running wind guide portion that guides running wind between itself and the muffler cover.
Since the running wind is introduced into the gap between the muffler cover and the muffler main body from the running wind guide portion between the second muffler cover and the muffler cover, the cooling performance of the muffler cover is improved, and the running wind is suppressed. It is possible to prevent the occurrence of turbulence due to entrainment in the exhaust outlet.

According to a preferred embodiment of the invention,
A gap is provided between the second muffler cover and the muffler main body, and the second muffler cover has an intake port directed toward the outside of the vehicle for inflowing running wind on the upper surface thereof. .
The running wind taken into the gap between the second muffler cover and the muffler main body from the intake port is discharged from the introduction wind guide hole by the introduction wind guide part in the muffler cover, so that it flows around the outer periphery of the second muffler cover. It is possible to prevent the generation of turbulence due to running wind.

According to a preferred embodiment of the invention,
The muffler main body is provided so as to incline upward to the rear.
In the case of a muffler body that slopes upward to the rear, the upper surface of the second muffler cover is likely to be hit by running wind. well taken in.

According to the muffler device of the present invention,
By providing an introduction wind guide section that guides the running wind to the side of the exhaust outlet, the running wind is prevented from hitting the vicinity of the exhaust outlet and the occurrence of turbulence in the vicinity of the exhaust outlet is prevented. can be prevented, the exhaust flow can be improved, and the influence on the running performance can be eliminated.
In addition, the exhaust outlet of the tail pipe is oriented rearward, which reduces the man-hours for molding and combining the tail pipe and the muffler cover.

1 is a schematic diagram showing a right side surface of a motorcycle provided with a muffler device according to this embodiment, excluding a vehicle body cover; FIG. 2 is a right side view showing the exhaust pipe and muffler device of FIG. 1 taken out; FIG. 3 is a top view of the exhaust pipe and the muffler device as viewed from the arrows III-III in FIG. 2; FIG. 1 is a perspective view showing the relationship between a first muffler cover and a second muffler cover with respect to a muffler body in a muffler device; It is a right side cross-sectional view of the main part of the muffler device. FIG. 3 is a rear external view of the first muffler cover viewed from arrow VI-VI in FIG. 2; FIG. 3 is a front inner surface view of the first muffler cover viewed from the VII-VII arrow in FIG. 2; FIG. 3 is a perspective view of the rear end side of the muffler device as viewed from the vehicle inner rear side; A first muffler cover is shown removed. FIG. 3 is a plan cross-sectional view of the first muffler cover and the muffler main body, taken along the line IX-IX in FIG. 2;

A muffler device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9. FIG.
In the present embodiment, the straddle-type vehicle equipped with a muffler device indicates the case of a motorcycle, and directions such as front, rear, left, right, up, and down in the claims and the description of this specification refer to the vehicle (motorcycle) of the present embodiment. shall follow the direction of
The arrow FR in the drawing indicates the front of the vehicle, LH the left of the vehicle, RH the right of the vehicle, and UP the upper of the vehicle.

FIG. 1 is a schematic right side view of an example of a general aspect of a motorcycle 1 equipped with a muffler device according to the present embodiment, excluding a vehicle body cover.
As shown in FIG. 1, the vehicle body frame 2 of the motorcycle ("straddle-type vehicle" in the present invention) 1 according to the present embodiment has a main frame 21 extending rearward from a head pipe 20 slightly downward. When viewed from the side, it further forms a bent portion 21a and bends downward to form a steeply inclined portion 21b to reach the pivot frame 22. As shown in FIG.

A down frame 23 extends downward from the head pipe 20 at a steep angle, substantially parallel to the steeply inclined portion 21b of the main frame 21 in a side view.
A pair of left and right seat rails 24 extend rearward from the bent portion 21a of the main frame 21, and a pair of left and right backstays 25 connecting the rear portions of the seat rails 24 and the pivot frame 22 support the seat rails 24. there is

In the vehicle body frame 2 as described above, the front fork 11 is pivotally supported on the head pipe 20, and the front wheel 12 is supported on the lower end thereof.
A pivot frame 22 connected to the lower portion of the steeply inclined portion 21b of the main frame 21 has a rear fork 13 pivoted at its front end and extends rearward, and a rear wheel 14 is pivotally supported at its rear end. A rear cushion (not shown) is interposed between the body frame 2 and the vehicle body frame 2 .
A fuel tank 16 is installed on the front portion of the main frame 21, and behind the fuel tank 16, a passenger seat 17A for the driver and a pillion seat 17B for the fellow passenger are supported by seat rails 24 and provided in the front and rear directions. there is

In this embodiment, the motorcycle 1 has the internal combustion engine 3 mounted below the main frame 21 and in front of the steeply inclined portion 21b. The internal combustion engine 3 is suspended on the body frame 2 by fastening the front portion of the crankcase 30 to a bracket 23a attached to the lower end of the down frame 23, and fastening the rear portion of the crankcase 30 to the pivot frame 22. .

The internal combustion engine 3 of this embodiment includes the transmission 4 at the rear portion within the crankcase 30 to form a so-called power unit, and the crankshaft 31 is oriented in the vehicle width direction of the motorcycle 1, that is, in the left-right direction. It is an air-cooled single-cylinder four-stroke cycle internal combustion engine mounted on the motorcycle 1.

A main shaft and a counter shaft (not shown) of the transmission 4 are provided parallel to the crankshaft 31 at the rear portion of the crankcase 30. The countershaft penetrates the crankcase 30 to the left and protrudes to the outside. It is the final output shaft of the power unit, and has an output sprocket (not shown) on the protruding part. A drive chain 41 wound around an output sprocket is laid over a driven sprocket 42 on the rear wheel 14 side to constitute a chain transmission mechanism, and power is transmitted to the rear wheel 14 .

The internal combustion engine 3 is suspended on the crankcase 30 in a posture in which the cylinder axis is tilted forward and the cylinder block 32, the cylinder head 33, and the cylinder head cover 34 are erected.
An intake system device 50 is provided rearwardly from the cylinder head 33 of the internal combustion engine 3 and connected to an intake port 35 of the internal combustion engine 3 to reach an air cleaner case 51 .
An exhaust pipe 55 extends forward from the cylinder head 33 by connecting to the exhaust port 36 and bends downward to extend rearward under the internal combustion engine 3 to reach the muffler device 7 on the right side of the rear wheel 14 .

2 is a right side view showing the exhaust pipe 55 and the muffler device 7 taken out from FIG. 1, and FIG. 3 is a top view of the exhaust pipe 55 and the muffler device 7 as viewed from the arrows III--III in FIG.
As shown in FIG. 2, the muffler body 70 of the muffler device 7 connected to the rear end of the exhaust pipe 55 is inclined slightly upward and the rear end 70b is directed toward the rear of the vehicle (see FIG. 1). .
At the upper part of the muffler body 70, a front mounting bracket 71 is provided at the front portion thereof, and a rear mounting bracket 72 is provided at the rear portion thereof so as to protrude upward.

In this embodiment, the front mounting bracket 71 is fastened to the pivot frame 22a, and the rear mounting bracket 72 is fastened to the lower end of the pillion step support stay 26 attached to the backstay 25 (see FIG. 1). It should be noted that where on the vehicle body frame 2 it is fixed is not limited.
Therefore, in this embodiment, the muffler body 70 of the muffler device 7 is fixed to the vehicle body frame 2, and the internal combustion engine 3 is also fixed to the vehicle body frame 2. Connected regardless of movement.

As shown in FIG. 2, a muffler body 70 to which the rear end of the exhaust pipe 55 is connected is internally provided with a tail pipe 74 having an exhaust outlet 74a projecting rearward (see FIG. 5).
Around the exhaust outlet 74a of the tail pipe 74 projecting rearward from the rear end 70b of the muffler body 70, there is a first muffler cover ("muffler cover" in the present invention) mounted with a gap 81 between the muffler body 70 and the exhaust outlet 74a. A cover") 8 is provided. The first muffler cover 8 covers the entire rear end portion 70b of the muffler body 70 from behind, forms a so-called tail cap (see FIGS. 4, 5 and 9), and is made of resin.
Therefore, it is possible to protect surrounding people from the heat of the rear end portion 70b of the muffler body 70, and since it is made of resin, it is possible to reduce weight and cost, and it is possible to reduce the generation of radiant heat, thereby protecting the surroundings. Protects against radiant heat.

In addition, the muffler device 7 has a second muffler cover (“second muffler cover” in the present invention) 9 covering the outer side surface 70a from the upper side to the right side of the muffler body 70, and a gap 75 is provided between the muffler body 70 and the muffler body 70. (see FIGS. 3 and 5).
As schematically illustrated in FIG. 3, a first mounting base 76 and a second mounting base 77 are provided on the right side of the muffler body 70, and the first mounting base 76 is provided on the inner surface of the second muffler cover 9. The gap 75 is formed between the second muffler cover 9 and the muffler main body 70 by fastening the bolts 98 through the fastening holes 97 of the second muffler cover 9 to the second mount 77 while engaging the engaging portion 96 . can be installed with the

Further, from the upper surface 9a to the side surface 9c of the second muffler cover 9, an intake port 90 is provided toward the outer side of the vehicle, through which ambient running wind is introduced.
Therefore, the running wind around the muffler device 7 taken into the gap 75 between the second muffler cover 9 and the muffler main body 70 from the intake port 90 is guided into the first muffler cover 8 (broken line in FIGS. 2 and 3). white arrow), the first muffler cover 8 discharges the introduced air through the introduced air guide hole 83 by the introduced air guide part 84 described later (see FIGS. 6 and 7), so that the running wind flowing around the outer circumference of the second muffler cover 9 Turbulent flow can be prevented.

4 is a perspective view showing the relationship between the first muffler cover 8 and the second muffler cover 9 with respect to the muffler body 70 in the muffler device 7. FIG.
As shown in FIG. 4, the first muffler cover 8 has a gap 81 between it and the rear end portion 70b of the muffler body 70, through which running wind (white arrow A in FIG. 4) is introduced. The rear end 9b of the second muffler cover 9 and the front end 8a of the first muffler cover 8 form a gap 82 between the rear end 9b and the front end 8a of the first muffler cover 8. , and the traveling wind (white arrow B in FIG. 4) is introduced into the gap 81 between the first muffler cover 8 and the muffler body 70 from the gap 82 of the traveling wind guide portion 91, so that the first muffler The cooling performance of the cover 8 is improved.

The muffler body 70 of the muffler device 7 of the present embodiment is inclined slightly upward to the rear and the rear end portion 70b is directed toward the rear of the vehicle (see FIGS. 1 and 2). Although the upper surface 9a of the second muffler cover 9 is likely to be hit by running wind, the hitting running wind can be efficiently taken into the gap 75 between the second muffler cover 9 and the muffler body 70 from the suction port 90. As a result, the running wind can be introduced into the first muffler cover 8 through the gap 75, and the cooling performance of the first muffler cover 8 is improved. can be prevented.
In addition, since the muffler body 70 is raised rearward, the running wind enters through the clearance 82 of the running wind guide portion 91 and can be introduced into the first muffler cover 8, thereby improving the cooling performance of the first muffler cover 8. In addition, it is possible to prevent the occurrence of turbulent flow due to entrainment of the running wind around the muffler device 7 into the exhaust outlet 74a.

FIG. 5 is a right side cross-sectional view of the main part of the muffler device 7. As shown in FIG. The rear end portion 55a of the exhaust pipe 55 inserted into the muffler body 70 opens into the first expansion chamber 79a between the first partition plate 78a and the second partition plate 78b to release the exhaust pressure of the exhaust gas. . The exhaust gas further passes through the communicating pipe 78c passing through the second partition plate 78b, enters the second expansion chamber 79b between the second partition plate 78b and the rear end plate 73, and releases the exhaust pressure. Exhaust gas 74b with reduced exhaust pressure passes through a straight tail pipe 74 passing through a rear end plate 73 and is discharged from an exhaust outlet 74a at the rear end to the rear of the muffler device 7 with a noise reduction effect. (Black arrow 74b in FIGS. 4 and 5). The interiors of the first expansion chamber 79a and the second expansion chamber 79b may be filled with glass wool or the like.
A first muffler cover 8 surrounds the tail pipe 74 protruding from the rear end portion 70b of the muffler body 70 . The second muffler cover 9 is provided on the outer surface 70a of the muffler main body 70 with a gap 75 as described above.
In the present invention, the structure inside the muffler body 70, such as the number and arrangement of expansion chambers, is not limited to those described above, and FIG. 5 is an example.

6 is a rear external view of the first muffler cover 8 viewed from the arrow VI-VI in FIG. 2, and FIG. 7 is a front internal view of the first muffler cover 8 viewed from the arrow VII-VII in FIG.
As shown in FIGS. 6 and 7, the first muffler cover 8 has an annular shape when viewed from the front-rear direction, and has a central opening 80 surrounding a tail pipe 74 projecting rearward from the muffler body 70. there is

A vertically elongated slit-like airflow guide hole 83 is provided through the right portion of the first muffler cover 8, that is, the vehicle outer side portion 8c. An introductory air guide portion 84 is erected on the inner surface with a vertical length exceeding the vertical length of the introductory air guide hole 83 .
That is, the airflow guide hole 83 is spaced apart from the exhaust outlet 74a of the tail pipe 74 and opens toward the rear. Between the hole 83 and the exhaust outlet 74a, an upright wall is provided parallel to the discharge direction (black arrow in FIGS. 4 and 5) of the exhaust gas 74b discharged from the exhaust outlet 74a.

As such, in this embodiment, the running wind introduced from the gap 81 between the first muffler cover 8 and the rear end portion 70b of the muffler body 70 is directed to the side of the exhaust outlet 74a with respect to the exhaust outlet 74a. A guiding wind guide portion 84 is provided to prevent running wind from hitting the vicinity of the exhaust outlet 74a, prevent turbulent flow from occurring near the exhaust outlet 74a, and improve the exhaust flow. The influence on running performance can be eliminated.
In addition, the airflow introduced into the first muffler cover 8 can be discharged from the airflow guide hole 83 without hitting the exhaust gas 74b (black arrow in FIGS. 4 and 5) by the airflow guide portion 84. The introduction air guide part 84 guides the running wind in the direction parallel to the direction in which the exhaust gas 74b is discharged from the exhaust outlet 74a, so that an air curtain 83a for the running wind can be formed in the direction parallel to the direction in which the exhaust gas 74b is discharged. (See FIGS. 4 and 9), it is possible to prevent the wind from being drawn into the first muffler cover 8 from the outer side surface of the vehicle.

A support stay engagement portion 89 that engages with a muffler cover engagement portion 85d (see FIG. 8), which will be described later, projects from above the introduction air guide portion 84 inside the first muffler cover 8. As shown in FIG.
In the left part of the first muffler cover 8, that is, in the inner part 8d of the vehicle, fastening holes 87 for fastening to a muffler cover fixing part 86 (see FIG. 8) of a first muffler cover support stay 85, which will be described later, are formed vertically. A ventilation hole 88 is provided at two locations and passes through the first muffler cover 8 in the front-rear direction between them.
Therefore, the traveling wind that flows into the gap 81 along the vehicle inner side surface of the muffler body 70 is also discharged from the ventilation hole 88 to the rear of the vehicle, forming a ventilation flow 88a parallel to the exhaust gas 74b discharged from the exhaust outlet 74a. (See FIG. 9).

FIG. 8 is a perspective view of the rear end side of the muffler device 7 as seen from the vehicle inner rear side, with the first muffler cover 8 removed.
A straight tail pipe 74 penetrates the rear end plate 73 of the muffler body 70 and protrudes rearward (see FIG. 5). It is fixed to the plate 73 by a welded portion 85c.

The first muffler cover support stay 85 is a sheet metal member having a shape that generally closes the central opening 80 of the first muffler cover 8 .
An upper support leg 85a and a lower support leg 85b are formed on the first muffler cover support stay 85 so as to bend forward, and their front ends are fixed to the rear end plate 73 at welded portions 85c.
A muffler cover fixing portion 86 is formed by bending forward on the left portion of the first muffler cover support stay 85, that is, on the inside portion of the vehicle, and fastening holes 86a are provided at two locations.
The bent front end of the muffler cover fixing portion 86 is fixed to the rear end plate 73 by a welded portion 85c.
A muffler cover engaging portion 85d is provided on the opposite side of the muffler cover fixing portion 86, that is, on the right side of the vehicle.

The first muffler cover 8 is arranged so as to cover the first muffler cover support stay 85 from the rear, and the fastening bolts 86b are inserted into the fastening holes 87 from the outside of the vehicle inner portion 8d, and the first muffler cover support stay 85 is installed. It is fastened to the muffler body 70 by screwing it into the fastening hole 86a.
At this time, the muffler cover engagement portion 85d of the first muffler cover support stay 85 is fitted into the support stay engagement portion 89 on the inner surface of the vehicle outer side portion 8c of the first muffler cover 8 shown in FIG. The position of the muffler cover 8 is fixed.

9 is a cross-sectional plan view of the first muffler cover 8 and the muffler main body 70 taken along line IX-IX in FIG. Due to the slightly lower section, the tail pipe 74 is not visible.
The lower support leg 85b of the first muffler cover support stay 85 is fixed to the rear end plate 73 of the muffler body 70 with a welded portion 85c, and the first muffler cover is inserted into the fastening hole 86a on the lower side of the bent muffler cover fixing portion 86. A state in which the vehicle inner side portion 8d of 8 is fastened is illustrated.
Also shown are the introduction air guide portion 84 erected on the inner surface of the vehicle outer side portion 8c of the first muffler cover 8 and the lower end of the introduction air guide hole 83 opened outside thereof.

As shown in FIG. 9, the running wind that has flowed in through the gap 81 between the muffler body 70 and the first muffler cover 8 is guided by the introduced wind guide portion 84 inside the first muffler cover 8 to the exhaust outlet of the tail pipe 74. An air curtain 83a is formed in parallel with the exhaust gas 74b (black arrow in FIG. 9) discharged from the exhaust outlet 74a and is discharged rearward from the vehicle through the introduction air guide hole 83 separated from the air curtain 83a.
The running wind that flows into the gap 81 along the vehicle inner side surface of the muffler body 70 is also separated from the exhaust outlet 74a by the muffler cover fixing portion 86 of the first muffler cover support stay 85, and is exhausted from the ventilation hole 88 to the rear of the vehicle. A ventilation flow 88a is formed in parallel with the exhaust gas 74b discharged from the outlet 74a and discharged.

The muffler device 7 of the present embodiment is constructed as described above, and its action and effect will be described below.
That is, a tail pipe 74 having an exhaust outlet 74a protruding rearward is provided at the rear of the muffler body 70, and a first muffler cover 8 spaced apart from the muffler body 70 is provided around the exhaust outlet 74a. A gap 81 is provided between the first muffler cover 8 and the muffler main body 70 to introduce running wind.
An introduction wind guide portion 84 is provided for guiding the running wind introduced through the gap 81 toward the exhaust outlet 74a to the side of the exhaust outlet 74a.

Conventionally, the muffler cover is separated from the muffler main body 70 to introduce the traveling wind into the gap 81 in order to reduce the occurrence of turbulence caused by the wind flowing around the outer periphery of the muffler cover getting caught in the downstream end of the muffler device. However, in that case, the running wind that flowed in from the gap 81 generated turbulence near the exhaust outlet 74a.
However, in the present embodiment, by providing the introduction wind guide portion 84 for guiding the running wind to the side of the exhaust outlet 74a with respect to the exhaust outlet 74a, the running wind is prevented from hitting the vicinity of the exhaust outlet 74a. The generation of turbulence in the vicinity of the exhaust outlet 74a can be prevented, the flow of the exhaust gas can be improved, and the influence on the running performance can be eliminated.

The first muffler cover 8 has an airflow guide hole 83 that opens rearward away from the exhaust outlet 74a in the vehicle outer side portion 8c. Inside, it is located between the exhaust outlet 74a and the introduction air guide hole 83, and stands parallel to the discharge direction of the exhaust gas 74b discharged from the exhaust outlet 74a.
Therefore, the airflow introduced into the first muffler cover 8 can be discharged to the airflow guide hole 83 by the airflow guide portion 84 without hitting the exhaust gas 74b.
Furthermore, the introduction wind guide portion 84 guides the introduced traveling wind in a direction parallel to the discharge direction of the exhaust gas 74b, so that an air curtain 83a of the traveling wind can be formed in the direction parallel to the discharge direction of the exhaust gas 74b. It is possible to prevent wind from being drawn into the first muffler cover 8 from the outer side surface of the vehicle.

The first muffler cover 8 is a tail cap that covers the entire rear end portion 70b of the muffler body 70, and can protect surrounding people from the heat of the rear end portion 70b of the muffler body 70. As shown in FIG.
In addition, since the first muffler cover 8 is made of resin, it is possible to reduce the weight and cost, reduce the generation of radiant heat, and protect the surroundings from the radiant heat.

The muffler device 7 includes a second muffler cover 9 that covers the outer surface 70a of the muffler body 70, and the second muffler cover 9 and the first muffler cover 8 form a stepped combined portion that guides the running wind. It has a part 91.
Therefore, the traveling wind is introduced into the gap 81 between the first muffler cover 8 and the muffler main body 70 through the gap 82 of the traveling wind guide portion 91 between the second muffler cover 9 and the first muffler cover 8. , the cooling performance of the first muffler cover 8 is improved.

A gap 75 is provided between the second muffler cover 9 and the muffler main body 70, and the second muffler cover 9 has an intake port 90 directed toward the outside of the vehicle, through which running wind flows into the upper surface 9a. ing.
Therefore, the running wind introduced into the gap 75 between the second muffler cover 9 and the muffler main body 70 from the suction port 90 is discharged from the introduced wind guide hole 83 by the introduced wind guide portion 84 in the first muffler cover 8. Thus, the occurrence of turbulent flow due to running wind flowing around the outer circumference of the second muffler cover 9 can be prevented.

The muffler body 70 is provided so as to be inclined rearwardly upward. In the case of the muffler body 70 inclined rearwardly upwardly, the upper surface 9a of the second muffler cover 9 is likely to be hit by running wind. It can be efficiently introduced into the gap 75 between the second muffler cover 9 and the muffler main body 70 from the suction port 90 .

Although the muffler device according to one embodiment of the present invention has been described above, the aspect of the present invention is not limited to the above-described embodiment, and includes various implementations within the scope of the present invention. Of course, any muffler device that satisfies the requirements of claim 1 may be used.
Moreover, the straddle-type vehicle equipped with the muffler device of the present invention is not limited to the motorcycle shown as a general mode example in the embodiment, and may be a motorcycle of various forms and structures. , a four-wheeled buggy, and various straddle-type vehicles.
The internal combustion engine is not limited to the air-cooled single-cylinder four-stroke cycle internal combustion engine of the embodiment, and may be other types of multi-cylinder internal combustion engines.
In addition, for convenience of explanation, the left and right arrangement of each device is specifically described as shown in the figure, but the arrangement may be reversed left and right to that shown in the above embodiment, and is included in the present invention. .

DESCRIPTION OF SYMBOLS 1... Motorcycle, 2... Body frame, 3... Internal combustion engine, 7... Muffler device, 8... First muffler cover ("muffler cover" in the present invention), 8a... Front end, 8b... Rear end, 8c... Vehicle Outer portion 8d Vehicle inner portion 9 Second muffler cover ("second muffler cover" in the present invention) 9a Upper surface 9b Rear end 9c Side 13 Rear fork 14 Rear Wheel 22 Pivot frame 23 Down frame 23a Bracket 24 Seat rail 25 Back stay 26 Pillion step support stay 30 Crankcase 31 Crankshaft 33 Cylinder head 36 Exhaust port 55 Exhaust pipe 55a Rear end 70 Muffler body

70a Outer surface

70b Rear end 71 Front mounting bracket 72 Rear mounting bracket 73 Rear end plate 74 ...Tail pipe 74a...Exhaust outlet 74b...Exhaust gas 75...Gap 80...Center opening 81...Gap 82...Gap 83...Introduction air guide hole 83a...Air curtain 84...Introduction air guide part 85 First muffler cover support stay 85a Upper support leg 85b Lower support leg 85c Welding portion 85d Muffler cover engaging portion 86 Muffler cover fixing portion 86a Fastening hole 86b Fastening bolt , 87 ... fastening hole, 88 ... ventilation hole, 88a ... ventilation flow, 89 ... support stay engaging portion, 90 ... suction port, 91 ... traveling wind guide portion

Claims

In a muffler device (7) having a muffler body (70) connected to a rear end (55a) of an exhaust pipe (55) of an internal combustion engine (3) of a straddle-type vehicle (1),
A tail pipe (74) with an exhaust outlet (74a) projecting rearward is provided at the rear of the muffler body (70),
A muffler cover (8) spaced apart from the muffler main body (70) is provided around the exhaust outlet (74a),
A gap (81) is provided between the muffler cover (8) and the muffler body (70), through which running wind is introduced,
A muffler characterized by comprising an introduction wind guide portion (84) for guiding the running wind introduced through the gap (81) to the side of the exhaust outlet (74a) with respect to the exhaust outlet (74a). Device.
The muffler cover (8) has an introduction air guide hole (83) opening rearward away from the exhaust outlet (74a) in the vehicle outer side portion (8c) of the rear portion thereof,
The airflow guide portion (84) is located inside the muffler cover (8) between the air discharge outlet (74a) and the airflow guide hole (83), and the air flow from the air discharge outlet (74a) is provided. 2. The muffler device according to claim 1, wherein the muffler device stands parallel to the discharge direction of the discharged exhaust gas.
The muffler device according to claim 1 or claim 2, wherein the muffler cover (8) is a tail cap that covers the entire rear end portion (70b) of the muffler body (70).
The muffler device according to any one of claims 1 to 3, wherein the muffler cover (8) is made of resin.
The muffler device (7) covers the outer surface (70a) of the muffler body (70) and has a running wind guide portion (91) for guiding running wind between itself and the muffler cover (8). 5. The muffler device according to any one of claims 1 to 4, further comprising a muffler cover (9).
A gap (75) is provided between the second muffler cover (9) and the muffler body (70),
6. The muffler device according to claim 5, wherein the second muffler cover (9) has an intake port (90) directed toward the outside of the vehicle, through which running air flows in, on the upper surface thereof.
The muffler device according to claim 6, characterized in that the muffler body (70) is inclined rearwardly upward.