JP5770238B2 - Vehicle exhaust structure - Google Patents

Description

  The present invention relates to an exhaust structure for a vehicle.

  2. Description of the Related Art Conventionally, an exhaust device mounted on a vehicle is known in which a muffler at a rear portion of an exhaust device extending rearward from an engine is disposed inside a rear cowl that covers a rear portion of a vehicle body (see, for example, Patent Document 1). . In Patent Document 1, two tail pipes that exhaust the exhaust to the outside are provided.

JP 2005-83286 A

By the way, when the muffler is arranged inside the rear cowl like the conventional exhaust structure, it is necessary to form the muffler according to the shape of the rear cowl, and the shape of the muffler is restricted. Even under such restrictions, depending on the required engine output characteristics, it is desirable to make the tail pipe as long as possible in order to increase the exhaust flow rate of the final stage.
The present invention has been made in view of the above-described circumstances, and an object thereof is to enable a tail pipe to be elongated in an exhaust structure of a vehicle in which a muffler is covered with a rear cowl.

In order to achieve the above object, the present invention includes an engine (11), an exhaust device (25) of the engine (11), and a rear cowl (35) that covers a rear portion of the vehicle, and the exhaust device (25) includes: A plurality of expansion chambers (C1, C2) each having an exhaust pipe (28) and a muffler (29) connected to a rear portion of the exhaust pipe (28), the muffler (29) being partitioned by a partition wall (65) A connecting pipe (67, 68) for connecting the plurality of expansion chambers (C1, C2), and a tail pipe (69) for discharging exhaust gas from the muffler (29), wherein the muffler (29) In the exhaust structure of the vehicle covered with the rear cowl (35), the outer shape of the muffler (29) and the rear cowl (35) has a shape in which the lateral width becomes narrower toward the rear of the vehicle, and the tail pipe (69) And the connecting pipe (6 , 68) are provided through the partition wall (65), and the penetrating positions where the tail pipe (69) and the connecting pipe (67, 68) pass through the partition wall (65) are in the vertical direction. The catalyst (67) that is offset and accommodated in the muffler (29) is supported by the partition wall (65), and the catalyst (67) and the connection pipe (68) are substantially the same height in the vertical direction. disposed, characterized in Rukoto.
According to the present invention, since the connecting pipe does not interfere with the tail pipe at the penetrating position, the tail pipe can be lengthened even if the width of the muffler and the rear cowl becomes narrower toward the rear of the vehicle. Further, the muffler can be reduced in size in the width direction. Moreover, even if it is the structure which accommodated the catalyst in the muffler, it can prevent that a catalyst interferes with a tail pipe, and can lengthen a tail pipe.

Further, according to the present invention, one end (69a) of the tail pipe (69) is disposed in the expansion chamber (C2) positioned in the foremost position among the expansion chambers of the muffler (29), and the tail pipe (69) The other end (69b) of the muffler (29) is opened to the outside air from the rear part of the muffler (29).
According to the present invention, the tail pipe can be extended from the expansion chamber located at the foremost position, and the tail pipe can be lengthened.
Further, according to the present invention, the muffler (29) is partitioned into a rear first expansion chamber (C1) and a front second expansion chamber (C2), and the exhaust pipe (28) to the muffler (29). The exhaust gas introduced into the gas flows into the second expansion chamber (C2) via the connection pipes (67, 68), and enters the second expansion chamber (C2) at one end (69a) of the tail pipe (69). The other end (69b) of the tail pipe (69) is open to the outside from the rear part of the muffler (29).
According to the present invention, the tail pipe can be extended from the front second expansion chamber to the rear part of the muffler, and the tail pipe can be lengthened.

Also, the present invention, the catalyst (67) is characterized by a flat shape having the longitudinal direction and the width direction.
According to the present invention, the catalyst can be provided in a compact manner while ensuring the capacity of the catalyst, and the catalyst does not interfere with the tail pipe, so that the tail pipe can be lengthened.

Further, according to the present invention, the outer shape of the muffler (29) is such that the tail pipe (69) is more than the lateral width (W1) at the height position where the connecting pipe (68) and the catalyst (67) are arranged. The width (W2) of the arranged height direction position is formed small.
According to the present invention, the lateral width of the rear cowl that covers the vicinity of the tail pipe can be reduced, and the muffler and the rear cowl can be reduced in size.

Further, the present invention includes a cylindrical cover member (70) that covers a part of the tail pipe (69) from the outside in the radial direction, and ends of the catalyst (67) and the connection pipe (68) are the muffler. The space between the cover member (70) and the tail pipe (69) is opposed to the inner wall of (29), and the expansion is performed via the connecting portion (72) between the cover member (70) and the inner wall. It is characterized by communicating with the chamber (C1).
According to the present invention, since the space between the cylindrical cover member and the tail pipe can be used as an expansion chamber, the capacity of the expansion chamber can be secured while reducing the size of the muffler.
Further, the present invention is characterized in that the cover member (70) is connected to the muffler (29) by welding, and the connection part (73a) is formed in a tapered shape in a side view.
According to the present invention, the area of the welded portion of the cover member can be increased and the rigidity can be improved.

In the exhaust structure for a vehicle according to the present invention, the tail pipe can be lengthened even if the width of the muffler and the rear cowl becomes narrower toward the rear of the vehicle. Further, the muffler can be reduced in size in the width direction.
Further, the tail pipe can be extended from the foremost expansion chamber.
Also, the tail pipe can be elongated by extending from the second expansion chamber at the front part to the rear part of the muffler.
Furthermore, the catalyst does not interfere with the tail pipe, and the tail pipe can be lengthened.
Further, the lateral width of the rear cowl can be reduced, and the muffler and the rear cowl can be reduced in size.
In addition, the capacity of the expansion chamber can be secured while reducing the size of the muffler.
Moreover, the area of the welding part of a cover member can be enlarged, and rigidity can be improved.

1 is a right side view of a motorcycle including an exhaust structure for a vehicle according to the present invention. It is a right view of the peripheral part of a rear cowl. It is the top view which looked at the rear cowl from the upper part. It is the top view which looked at the peripheral part of a rear cowl from the downward direction. It is a perspective view of a rear bank side exhaust device. It is the top view which looked at the muffler for back banks from upper direction. It is VII-VII sectional drawing of FIG. It is sectional drawing of the muffler for back banks when it sees from the left side. It is sectional drawing of the rear part of the muffler for rear banks. It is the front view which looked at the partition from the vehicle back side.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description, descriptions of directions such as front and rear, right and left and up and down are the same as directions with respect to the vehicle body unless otherwise specified. Further, in each figure, the symbol FR indicates the front of the vehicle body, the symbol UP indicates the upper side of the vehicle body, and the symbol LE indicates the left side of the vehicle body.

FIG. 1 is a right side view of a motorcycle 10 having a vehicle exhaust structure of the present invention.
In the motorcycle 10, an engine 11 is supported on a vehicle body frame F, a front fork 12 that supports a front wheel 2 is supported on a front end of the vehicle body frame F in a steerable manner, and a swing arm 13 that supports a rear wheel 3 is mounted on the vehicle body frame F. It is a vehicle provided on the rear side. The motorcycle 10 is a saddle-ride type vehicle in which a seat 14 on which a driver sits is supported on an upper portion of a body frame F.

  The vehicle body frame F includes a front end head pipe 15 that supports the front fork 12, a pair of left and right main frames 16 that extend rearward and rearwardly downward from the head pipe 15, and a pair of left and right center frames that extend downward from the rear portion of the main frame 16. 17. The vehicle body frame F also includes a pair of left and right seat frames (not shown) extending from the rear part of the main frame 16 to the rear part of the vehicle.

The swing arm 13 is supported by a pivot shaft 18 provided at the upper and lower intermediate portions of the left and right center frames 17 so as to be swingable up and down, and the rear wheel 3 is pivotally supported by an axle 19 at the rear end portion of the swing arm 13. The
A steering handle 20 is attached to the upper end portion of the front fork 12, and the front wheel 2 is supported on the lower end portion of the front fork 12 via an axle 21.
The fuel tank 22 is supported by the left and right center frames 17 behind the head pipe 15. The seat 14 is located behind the fuel tank 22 and is supported by the seat frame.

  The engine 11 is a V-type four-cylinder arranged in a front and rear V shape. The engine 11 includes a crankcase 23 that supports a crankshaft extending in the vehicle width direction, a front bank 47F that includes two cylinders that extend obliquely forward from the crankcase 23, and an inclination that extends backward from the crankcase 23. And a rear bank 47R composed of two cylinders.

The engine 11 has a front bank side exhaust device 24 connected to the front bank 47F, and a rear bank side exhaust device 25 (exhaust device) connected to the rear bank 47R.
The front bank side exhaust device 24 is disposed on the outer side of the swing arm 13 and the exhaust pipe 26 that is drawn out from the front surface of the cylinder head of each cylinder of the front bank and gathered on the rear end side. 26 and a front bank muffler 27 connected to the rear end.
The rear bank side exhaust device 25 is disposed at the rear end portion of the motorcycle 10 and the exhaust pipe 28 drawn from the rear surface of the cylinder head of each cylinder of the rear bank 47R and gathered together on the rear end side. And a rear bank muffler 29 connected to the rear end of the pipe 28.

The motorcycle 10 includes a resin body cover 30 that covers the vehicle body. The vehicle body cover 30 includes a front side cover 31 that covers the front portion of the engine 11, the head pipe 15 and the main frame 16, a front cowl 32 that covers the head pipe 15 from the front, and an under cover 33 that covers the engine 11 from below. . The vehicle body cover 30 includes a middle cover 34 that covers the rear bank exhaust device 25 below the seat 14 and a rear cowl 35 that covers the rear bank muffler 29 behind the seat 14.
A rear stay 36 is provided on the lower surface of the rear cowl 35 and extends rearward and rearward, and a pair of turn signals 37 projecting left and right are provided at the rear end of the rear stay 36. A plate-like license plate holder 38 that extends rearward and downward is provided at the rear end of the rear stay 36.
A rear wheel cover 39 that covers the rear wheel 3 from the front upper side is attached to the front portion of the swing arm 13. A front fender 40 is attached to the front fork 12.

FIG. 2 is a right side view of the peripheral portion of the rear cowl 35. FIG. 3 is a plan view of the rear cowl 35 as viewed from above. FIG. 4 is a plan view of the periphery of the rear cowl 35 as viewed from below.
2 to 4, the middle cover 34 has an upward extension 34 a that rises rearward and upward from the rear end side of the seat 14. Air introduction holes 34b and 34b communicating with the inside of the vehicle body cover 30 are provided on the left and right sides of the upper extension 34a.
The rear cowl 35 is provided continuously to the rear edge of the upward extension 34 a and extends to the rear end of the vehicle body cover 30.

  The outer shape of the rear cowl 35 is formed such that, in plan view, the lateral width increases toward the front end side and gradually decreases toward the vehicle rear side, and tapers toward the rear end side. Specifically, the outer shape of the rear cowl 35 in a plan view from above is such that the distance between the front edge 35a extending substantially straight in the vehicle width direction along the rear edge of the upper extension 34a and the rear side becomes smaller. As described above, side edge portions 35b and 35b extending rearward from the left and right ends of the front edge portion 35a and a rear edge portion 35c connecting the rear ends of the side edge portions 35b and 35b are provided.

The outer shape of the rear cowl 35 is formed so that the front end side is larger in the vertical direction in a side view, and the vertical thickness is gradually reduced toward the vehicle rear side, and is tapered toward the rear end side. .
The upper surface 41 of the rear cowl 35 is at the highest position in the center in the vehicle width direction, and is curved so as to become lower toward the outside in the vehicle width direction. It is formed to become.
The lower surface 42 of the rear cowl 35 is inclined so as to rise rearward in a side view. The lower surface 42 of the rear cowl 35 has a lower bulging portion 42a that bulges downward in the center in the vehicle width direction. It is formed to be curved. The downward bulging portion 42a extends from the front end of the rear cowl 35 to the rear portion.

On the left and right side surfaces of the front portion of the rear cowl 35, long ventilation holes 43 are provided in the front and rear direction. An inwardly bulging portion 43 a in which a part of the rear cowl 35 bulges inward is formed at the front portion of the ventilation hole 43.
In addition, on the lower surface 42 of the rear cowl 35, front and rear long exhaust holes 44, 44 are provided in the lower side portions 42b, 42b on the left and right sides of the lower bulging portion 42a. The ventilation holes 44 and 44 are located behind the ventilation holes 43. A rear opening 45 for exposing the rear portion of the rear bank muffler 29 is provided at the rear end portion of the downward bulging portion 42a.
The rear bank muffler 29 is cooled by the traveling air introduced from the air introduction holes 34 b and 34 b and discharged from the exhaust air holes 44 and 44 and the rear opening 45.
Stay fixing portions 46, 46 to which the front end of the rear stay 36 is fastened are provided at the base end portion of the downward bulging portion 42a between the rear opening 45 and the left and right exhaust holes 44, 44, respectively.

FIG. 5 is a perspective view of the rear bank side exhaust device 25.
As shown in FIG. 5, the exhaust pipe 28 of the rear bank side exhaust device 25 includes a pair of exhaust port connection pipes 50, 50 drawn backward from the cylinder head of each cylinder of the rear bank 47R, and an exhaust port connection pipe 50, The upper extension pipes 51 and 51 extending upward and rearward from the rear end of the 50 and the merge pipe 52 formed by joining the upper extension pipes 51 and 51 are provided. The exhaust pipe 28 extends rearward through one side (right side) in the vehicle width direction, which is the side where the front bank muffler 27 side is disposed.
The upper extension pipes 51, 51 are fitted to the exhaust port connection pipes 50, 50, and a plurality of springs 53 spanned between the exhaust port connection pipes 50, 50 and the upper extension pipes 51, 51. The exhaust port connection pipes 50 and 50 are connected.
An exhaust valve (not shown) that changes the area of the flow path of the merging pipe 52 is provided in the merging pipe 52, and a drive unit 54 that drives the exhaust valve is provided on the outer surface of the merging pipe 52. ing. The rear bank muffler 29 is connected to the rear end of the merge pipe 52.

FIG. 6 is a plan view of the rear bank muffler 29 as viewed from above. Here, in FIG. 6, the outer shape of the rear cowl 35 together with the rear bank muffler 29 is indicated by a two-dot chain line.
As shown in FIGS. 5 and 6, the rear bank muffler 29 includes a muffler main body 55 formed in a box shape that fits inside the rear cowl 35, and a tubular tail portion 56 that extends rearward from the rear portion of the muffler main body 55. Prepare.
The muffler main body 55 is formed by combining an upper half 59a (FIG. 8) and a lower half 59b (FIG. 8), which are obtained by dividing a box shape into two vertically. FIG. 6 shows a state where the upper half 59a is separated and removed from the muffler main body 55 in order to make the internal structure easy to see.
The muffler main body 55 is configured in accordance with the shape of the rear cowl 35, and its lateral width is the largest on the front end side and is formed to become smaller toward the rear of the vehicle. The outer shape of the muffler main body 55 has side edge portions 55a and 55a along the side edge portions 35b and 35b of the rear cowl 35 and a rear edge portion 55b connecting the rear ends of the side edge portions 55a and 55a in a plan view.

The muffler main body 55 has an exhaust pipe connecting portion 57 that bulges forward and downward on one side (right side) of the front surface in the vehicle width direction, and the rear end of the merging pipe 52 is connected to the exhaust pipe connecting portion 57. The
Muffler fixing stays 58 and 58 projecting in the vehicle width direction are provided on the left and right side surfaces of the front portion of the muffler main body 55. To the muffler fixing stays 58, 58, an inwardly bulging portion 43a (FIG. 2) of the ventilation hole 43 of the rear cowl 35 is fixed with a bolt from the outside.
The rear stay 36 includes a plate-like portion 36 a located below the tail portion 56. The left and right edges of the plate-like portion 36a extend so as to continue to the rear ends of the side edge portions 55a, 55a of the muffler main body 55, and the plate-like portion 36a is formed to have a smaller lateral width toward the rear side. The plate-like portion 36a has a width larger than that of the tail portion 56 of the rear bank muffler 29, and covers the tail portion 56 from below.

7 is a cross-sectional view taken along the line VII-VII in FIG. FIG. 8 is a cross-sectional view of the rear bank muffler 29 when viewed from the left side. FIG. 9 is a cross-sectional view of the rear part of the rear bank muffler 29.
As shown in FIGS. 6 to 9, the muffler main body 55 includes an upper wall portion 60 extending along the upper surface 41 of the rear cowl 35, a lower wall portion 61 extending rearward along the lower surface 42 of the rear cowl 35, and an exhaust pipe A front wall portion 62 provided with the connecting portion 57 and a rear wall portion 63 provided with the tail portion 56 are provided.

  The lower wall portion 61 extends along a lower wall bulging portion 61a that bulges downward at the center in the vehicle width direction along the lower bulging portion 42a of the lower surface 42 of the rear cowl 35, and lower surface side portions 42b and 42b of the rear cowl 35. The lower wall side portions 61b and 61b extend to the upper outer side and connect the lower wall bulging portion 61a to the left and right side edges of the upper wall portion 60. Since the lower wall bulging portion 61a and the lower surface side wall portions 61b and 61b bulge downward in a curved shape, it can be said that they form part of the left and right side wall portions of the muffler main body 55 in a side view.

As shown in FIG. 9, the muffler main body 55 is formed so that the lateral width W2 of the lower wall bulging portion 61a is smaller than the lateral width W1 on the upper wall portion 60 side. The width gradually decreases toward the portion 61a. That is, the cross-sectional shape of the muffler body 55 is formed in a substantially inverted triangular shape when viewed from the rear. The substantially inverted triangular shape is substantially symmetric with respect to the center line L in the vehicle width direction.
The rear cowl 35 is formed along the outer shape of the rear cowl 35 at a predetermined interval from the muffler main body 55, and the cross-sectional shape is similarly formed in a substantially inverted triangular shape.
A plate-shaped heat insulating member 64 is provided between the upper surface 41 of the rear cowl 35 and the upper wall portion 60 of the muffler main body 55.

  The muffler main body 55 is a multistage inflatable muffler and has a plate-shaped partition wall 65 that partitions the muffler main body 55 forward and backward. By providing the partition wall 65, a first expansion chamber C <b> 1 positioned at the rear portion of the muffler main body 55 and a second expansion chamber C <b> 2 positioned at the front portion of the muffler main body 55 are formed in the muffler main body 55. . The partition wall 65 is provided in the front part of the muffler body 55, and the volume of the first expansion chamber C1 on the rear side is larger than that of the second expansion chamber C2 on the front side.

  The rear bank muffler 29 is provided in the exhaust pipe connecting portion 57 and introduces an exhaust pipe 66 that introduces exhaust into the muffler main body 55, and a first communication pipe that guides the exhaust introduced into the introduction pipe 66 to the first expansion chamber C1. 67 (connection pipe, catalyst) and a second communication pipe 68 (connection pipe) for communicating the first expansion chamber C1 with the second expansion chamber C2. The rear bank muffler 29 extends rearward from the second expansion chamber C2 and communicates the second expansion chamber C2 with the outside of the rear bank muffler 29, and a cylinder covering the rear portion of the tail pipe 69. And a cover 70 (cover member).

  The lower wall portion 61 of the muffler main body 55 is inclined rearward and upward along the lower surface 42 of the rear cowl 35, and the partition wall 65 is provided substantially perpendicular to the lower wall portion 61. In other words, the partition wall 65 is disposed so as to be inclined forward by the inclination of the lower wall portion 61 with respect to the vertical direction.

FIG. 10 is a front view of the partition wall 65 viewed from the vehicle rear side.
The partition wall 65 is formed in a substantially inverted triangular shape in accordance with the shape of the muffler main body 55, and the peripheral edge portion is coupled to the inner wall of the muffler main body 55.
The partition wall 65 includes a support hole 65a into which the first communication pipe 67 is fitted, a support hole 65b into which the second communication pipe 68 is fitted, and a support hole 65c into which the tail pipe 69 is fitted. Have.
Each support hole 65a, 65b, 65c has a rib-like portion formed so as to bend the inner edge portion of the hole, and the first communication pipe 67, the second communication pipe 68, and the tail pipe 69 are formed in the rib shape. Fitted to and supported by the inner surface of the part.

The support hole portion 65a is disposed close to one side (right side) of the center line L in the upper part of the partition wall 65. The support hole 65 b is disposed on the other side (left side) of the center line L in the upper part of the partition wall 65. The support hole portion 65 b is disposed at a position overlapping the center line L in the lower portion of the partition wall 65.
The diameters of the support hole 65b and the support hole 65c are substantially equal. The support hole 65a has a larger diameter than the support hole 65b and the support hole 65c corresponding to the shape of the first communication pipe 67, and is formed in a flat shape that is longer in the vehicle width direction than in the vertical direction. ing.

  With reference to FIGS. 6 to 10, the first communication pipe 67 is arranged close to one side (right side) of the center line L in the upper part in the muffler main body 55. The first communication pipe 67 is fitted and supported by the support hole 65 a in a direction substantially orthogonal to the partition wall 65, and extends substantially straight rearwardly along the lower wall part 61.

The first communication pipe 67 is a pipe that is formed in a flat shape that is longer in the width direction than in the thickness direction, and is tapered so that the diameter increases toward the rear end side.
The front end 67a of the first communication pipe 67 is connected to the rear end of the introduction pipe 66 in the second expansion chamber C2. The rear end 67b of the first communication pipe 67 is positioned at the front and rear intermediate portions in the first expansion chamber C1. A catalyst body (not shown) in which a catalyst material is supported on a honeycomb-shaped carrier is fitted and supported on the inner peripheral surface of the first communication pipe 67. The catalyst body is provided over substantially the entire length of the first communication pipe 67. That is, the first communication pipe 67 is a pipe that introduces exhaust gas into the first expansion chamber C1, and is also a catalyst that purifies the exhaust gas.

The second communication pipe 68 is disposed on the other side (left side) of the center line L at the upper part in the muffler main body 55. The second communication pipe 68 is fitted and supported by the support hole 65 b in a direction substantially orthogonal to the partition wall 65, and extends substantially straight rearwardly along the lower wall part 61.
The second communication pipe 68 is a pipe having a substantially circular cross section whose diameter is substantially equal over the entire length. The front end 68a of the second communication pipe 68 is located in the second expansion chamber C2. The rear end 68b of the second communication pipe 68 extends rearward from the rear end 67b of the first communication pipe 67 and is located at the rear portion in the first expansion chamber C1.
The rear portion of the second communication pipe 68 is fitted and supported by a support wall 71 provided in the first expansion chamber C1.

The second communication pipe 68 is provided adjacent to the side of the first communication pipe 67 across the center line L, and is disposed in the muffler main body 55 at substantially the same height as the first communication pipe 67. . As shown in FIG. 7, the diameter of the second communication pipe 68 is smaller than the upper and lower thicknesses of the first communication pipe 67, and in a side view, the portion excluding the rear end portion of the second communication pipe 68 is the first communication pipe 67. It overlaps the tube 67.
The width W1 of the muffler body 55 corresponds to the width of the muffler body 55 at the height position where the first communication pipe 67 and the second communication pipe 68 are disposed. The horizontal width W2 of the muffler main body 55 corresponds to the horizontal width of the muffler main body 55 at the height position where the tail pipe 69 is disposed.

The tail pipe 69 is provided at the center in the vehicle width direction at the lower part in the muffler main body 55, and is arranged so that the center position thereof substantially coincides with the center line L. In other words, the tail pipe 69 is disposed so as to be offset downward with respect to the first communication pipe 67 and the second communication pipe 68.
The support hole portions 65a, 65b, and 65c of the partition wall 65 are through positions through which the first communication pipe 67, the second communication pipe 68, and the tail pipe 69 pass. The support hole portions 65a and 65b are provided at substantially the same height, and the support hole portion 65c is arranged offset downward with respect to the support hole portions 65a and 65b.

The tail pipe 69 is fitted and supported by the support hole 65c in a direction substantially orthogonal to the partition wall 65, and extends substantially straight rearwardly along the lower wall portion 61.
The tail pipe 69 is a tube having a substantially circular cross section with the same diameter over the entire length, and has a smaller diameter than the second communication tube 68 and a longer total length than the second communication tube 68. The front end 69a (one end) of the tail pipe 69 is supported by being fitted into the support hole 65c.

The rear wall portion 63 of the muffler main body 55 includes a vertical portion 63a facing the rear end 67b and the rear end 68b, and an inclined portion 63b extending forward from the lower end of the vertical portion 63a to the front and connected to the lower wall bulging portion 61a. Have Specifically, the inclined portion 63 b is provided by welding a plate member provided so as to close an opening formed in the rear wall portion 63 to the rear wall portion 63.
The inclined portion 63 b has an opening 72 (connecting portion with the inner wall) having a diameter larger than the outer diameter of the tail pipe 69. The tail pipe 69 has a tail pipe rear portion 69 c that extends to the outside of the muffler main body 55, and the tail pipe rear portion 69 c extends to the rear outside through the opening 72.

A cylindrical cover 70 is provided on the rear wall portion 63 of the muffler main body 55, and the cylindrical cover 70 covers the tail pipe rear portion 69c from the outer peripheral side. The cylindrical cover 70 includes a cylindrical portion 73 having a larger diameter than the tail pipe 69 and a cap 74 that closes the rear end of the cylindrical portion 73.
The tubular portion 73 has a tapered portion 73 a formed so as to cut the tubular portion 73 at an angle, and the tapered portion 73 a is connected to the peripheral portion of the opening 72. The cylindrical cover 70 is welded to the inclined portion 63b by a weld bead (not shown) formed at the peripheral edge of the tapered portion 73a. The cylindrical portion 73 is formed in a tapered shape having a larger diameter toward the rear side.

The cap 74 is an annular lid that plugs between the rear end support hole portion 74 a fitted to the rear end 69 b (the other end) of the tail pipe 69, and the outer peripheral surface of the rear end 69 b and the inner peripheral surface of the cylindrical portion 73. Part 74b. The lid 74b is formed in a tapered shape that extends rearward from the rear end 69b and has a larger diameter toward the rear.
The tail portion 56 has a double-pipe structure by covering the tail pipe 69 with a cylindrical cover 70. The cylindrical cover 70 is disposed substantially coaxially with respect to the tail pipe 69, and a rear expansion that communicates with the first expansion chamber C 1 through the opening 72 between the cylindrical cover 70 and the tail pipe 69. A chamber 75 is formed. Thereby, the capacity | capacitance of the 1st expansion chamber C1 is ensured largely.

Exhaust gas G1 introduced into the rear bank muffler 29 through the junction pipe 52 flows from the introduction pipe 66 on one side of the muffler body 55 to the first communication pipe 67 in the first expansion chamber C1, and the first communication pipe 67. After being purified by this catalyst, it flows into the first expansion chamber C1 at the rear and expands. The exhaust G2 expanded in the first expansion chamber C1 is reversed and flows into the second expansion chamber C2 through the second communication pipe 68 and expands in the front second expansion chamber C2. Further, a part of the exhaust G2 flows into the rear expansion chamber 75 and expands. Since the rear end 67b of the first communication pipe 67 faces the rear expansion chamber 75, the exhaust gas easily flows into the rear expansion chamber 75, and the rear expansion chamber 75 can be effectively used as the expansion chamber. The exhaust G3 expanded in the second expansion chamber C2 is reversed, passes through the tail pipe 69, and is discharged to the outside from the rear end 69b.
Here, the first communication pipe 67 is a pipe that directly introduces the exhaust gas of the exhaust pipe 28 into the first expansion chamber C1 at the rear portion. However, the first communication pipe 67 is supported by the partition wall 65, and the first expansion chamber C1 and the second expansion chamber C2. It can be said that it is a connecting pipe that connects

  In the present embodiment, the first communication pipe 67 and the second communication pipe 68 are provided side by side on the upper part in the muffler main body 55 formed in a substantially inverted triangular shape that protrudes downward, and the first communication pipe 67 and the first communication pipe 67 A tail pipe 69 is provided by being offset downward with respect to the two communication pipes 68. Thus, the first communication pipe 67 and the second communication pipe 68 can be prevented from interfering with the tail pipe 69, so that the tail pipe 69 can be made as long as possible, and the engine 11 has desired characteristics. Can do. Further, since the first expansion chamber C1 is provided at the rear portion of the muffler main body 55 and the second expansion chamber C2 is provided at the front portion of the muffler main body 55, the tail pipe 69 can be extended from the front portion of the muffler main body 55 to the rear portion. The tail pipe 69 can be lengthened.

Further, since the tail pipe 69 is offset downward at the center in the vehicle width direction with respect to the first communication pipe 67 and the second communication pipe 68, the muffler main body 55 can be formed in a substantially inverted triangular shape, and the rear cowl 35 covering the muffler main body 55 is provided. Can be made into a substantially inverted triangular shape with low air resistance. For this reason, the air resistance of the motorcycle 10 can be reduced while the tail pipe 69 can be lengthened. Further, since the running wind smoothly flows along the lower surface 42 of the rear cowl 35, hot air can be efficiently discharged from the exhaust holes 44 and 44.
In addition, since the first communication pipe 67 as a catalyst has a flat shape that is longer in the width direction than in the thickness direction, a space can be secured below the first communication pipe 67 while securing the capacity of the catalyst. For this reason, the first communication pipe 67 does not interfere with the tail pipe 69, and the first communication pipe 67 can be elongated by disposing the tail pipe 69 below the first communication pipe 67. Further, since the catalyst is provided in the muffler main body 55, it is not necessary to provide a catalyst in the exhaust pipe 28, and the exhaust flow rate in the exhaust pipe 28 can be increased, so that the exhaust efficiency is good.

As shown in FIG. 2, in the side view, the tail portion 56 has a lower surface continuously extending rearward from the lower surface of the lower bulging portion 42 a and a rear end slightly forward of the rear edge portion 35 c of the rear cowl 35. Located in. For this reason, the tail portion 56 can be seen integrally with the rear cowl 35 and the appearance is good.
Furthermore, since the stay fixing portions 46 and 46 are provided at the base end portion of the downward bulging portion 42a on the inner side in the vehicle width direction of the air exhaust holes 44 and 44, the stay fixing portions 46 and 46 obstruct the air exhaust holes 44 and 44. In addition, the rear bank muffler 29 can be effectively cooled.

  As described above, according to the embodiment to which the present invention is applied, the outer shape of the rear bank muffler 29 and the rear cowl 35 covering the rear bank muffler 29 has a shape in which the lateral width becomes narrower toward the rear of the vehicle. The tail pipe 69, the first communication pipe 67, and the second communication pipe 68 are provided through the partition wall 65, and the support hole portion 65 c that is a through position where the tail pipe 69 passes through the partition wall 65, and the first communication pipe. The support holes 65a and 65b, which are through positions where the 67 and the second communication pipe 68 pass through the partition wall 65, are offset in the vertical direction. Thus, the first communication pipe 67 and the second communication pipe 68 do not interfere with the tail pipe 69 at the penetrating position, so that the lateral width of the rear bank muffler 29 and the rear cowl 35 becomes narrower toward the rear of the vehicle. However, the tail pipe 69 can be lengthened. Further, the rear bank muffler 29 can be downsized in the width direction.

Further, the front end 69 a of the tail pipe 69 is disposed in the second expansion chamber C 2 positioned at the foremost position among the expansion chambers of the rear bank muffler 29, and the rear end 69 b of the tail pipe 69 is the rear portion of the rear bank muffler 29. Therefore, the tail pipe 69 can be extended from the second expansion chamber C2 located at the foremost position, and the tail pipe 69 can be lengthened.
The rear bank muffler 29 is divided into a rear first expansion chamber C1 and a front second expansion chamber C2, and exhaust gas introduced from the exhaust pipe 28 to the rear bank muffler 29 is supplied to the first communication pipe. 67 and the second communication pipe 68 flows into the second expansion chamber C2, the front end 69a of the tail pipe 69 is disposed in the second expansion chamber C2, and the rear end 69b of the tail pipe 69 is connected to the rear bank muffler 29. Open to the outside from the rear. For this reason, the tail pipe 69 can be extended from the front second expansion chamber C2 to the rear part of the rear bank muffler 29, and the tail pipe 69 can be lengthened.

Further, the first communication pipe 67 as a catalyst accommodated in the rear bank muffler 29 is supported by the partition wall 65, and the first communication pipe 67 and the second communication pipe 68 are arranged at substantially the same height in the vertical direction. Therefore, even if the first communication pipe 67 functioning as a catalyst is housed in the rear bank muffler 29, the catalyst can be prevented from interfering with the tail pipe 69, and the tail pipe 69 can be lengthened.
Moreover, since the 1st communicating pipe 67 as a catalyst is a flat shape which makes a longitudinal direction the width direction, the 1st communicating pipe 67 can be provided compactly up and down, ensuring the capacity | capacitance of a catalyst. For this reason, the first communication pipe 67 does not obstruct the tail pipe 69, and the tail pipe 69 can be lengthened.

  Furthermore, the outer shape of the rear bank muffler 29 is such that the lateral width W2 at the height direction position where the tail pipe 69 is disposed is larger than the lateral width W1 at the height direction position where the first communication pipe 67 and the second communication pipe 68 are disposed. Therefore, the lateral width of the rear cowl 35 that covers the vicinity of the tail pipe 69 can be reduced, and the rear bank muffler 29 and the rear cowl 35 can be reduced in size.

The rear pipe 69 has a tubular cover 70 that covers the rear part 69 c from the outside in the radial direction, and the rear ends 67 b and 68 b of the first communication pipe 67 and the second communication pipe 68 are rear wall parts of the rear bank muffler 29. 63, the space between the cylindrical cover 70 and the tail pipe rear portion 69c faces the first expansion chamber C1 via an opening 72 that is a connecting portion between the cylindrical cover 70 and the rear wall portion 63. Communicate. Thereby, since the space between the cylindrical cover 70 and the tail pipe rear portion 69c can be used as the rear expansion chamber 75, the capacity of the first expansion chamber C1 can be secured while reducing the size of the rear bank muffler 29.
Further, the cylindrical cover 70 is connected to the muffler main body 55 by welding, and the tapered portion 73a which is the connection portion is formed in a tapered shape in a side view, so that the area of the welding portion of the cylindrical cover 70 is reduced. Can be increased and rigidity can be improved.

In addition, the said embodiment shows the one aspect | mode which applied this invention, Comprising: This invention is not limited to the said embodiment.
In the above embodiment, the first communication pipe 67 and the second communication pipe 68 have been described as examples of the connection pipe, but the present invention is not limited to this, and at least the second communication pipe 68 is used. The tail pipe 69 may be offset in the vertical direction. In this case, for example, the exhaust gas is introduced into the first expansion chamber C <b> 1 by a pipe provided at a position different from the first communication pipe 67.
In the above embodiment, the first communication pipe 67 is described as being provided with a catalyst body. However, the present invention is not limited to this, and the first communication pipe 67 is provided with a catalyst body. There may not be just a tube.
In the above embodiment, the V-type four-cylinder engine 11 has been described as an example. However, the present invention is not limited to this, and at least the rear bank muffler 29 is covered by the rear cowl 35. It can be applied regardless of the engine form such as single cylinder, parallel cylinder, and horizontally opposed.

10 Motorcycle (vehicle)
11 Engine 25 Rear bank exhaust system (exhaust system)
28 Exhaust pipe 29 Rear bank muffler (muffler)
35 Rear cowl 65 Bulkhead 65a Support hole (penetration position)
65b Support hole (penetration position)
65c Support hole (penetration position)
67 1st communication pipe (connection pipe, catalyst)
68 Second communication pipe (connection pipe)
69 Tail pipe 69a Front end (one end)
69b Rear end (other end)
70 Cylindrical cover (cover member)
72 Opening (connection with inner wall)
73a Taper part (connection part)
C1 1st expansion chamber C2 2nd expansion chamber (expansion chamber located in the foremost position)
W1 width W2 width

Claims (7)

An engine (11), an exhaust device (25) of the engine (11), and a rear cowl (35) covering a rear portion of the vehicle are provided. The exhaust device (25) includes an exhaust pipe (28) and the exhaust pipe (28 ), And a plurality of expansion chambers (C1, C2) partitioned by a partition wall (65), and a plurality of expansion chambers (C1, C2). C2) connecting pipes (67, 68) and a tail pipe (69) for discharging exhaust gas from the muffler (29), the muffler (29) being covered by the rear cowl (35) In the exhaust structure,
The outer shape of the muffler (29) and the rear cowl (35) is a shape whose lateral width becomes narrower toward the rear of the vehicle,
The tail pipe (69) and the connection pipe (67, 68) are provided through the partition wall (65), and the tail pipe (69) and the connection pipe (67, 68) are connected to the partition wall (65). ) Penetrating positions that pass through) are offset from each other in the vertical direction ,
The catalyst (67) which is accommodated in the muffler (29) within is supported on the partition wall (65), said catalyst (67) and said connecting pipe (68) is Rukoto disposed at substantially the same height in the vertical direction A vehicle exhaust structure characterized by the above.   One end (69a) of the tail pipe (69) is disposed in the expansion chamber (C2) located in the foremost position among the expansion chambers of the muffler (29), and the other end (69b) of the tail pipe (69). 2. The exhaust structure for a vehicle according to claim 1, wherein the exhaust is opened to the outside air from a rear portion of the muffler (29).   The muffler (29) is divided into a first expansion chamber (C1) at the rear and a second expansion chamber (C2) at the front, and the exhaust introduced into the muffler (29) from the exhaust pipe (28) , Flows into the second expansion chamber (C2) via the connection pipes (67, 68), and one end (69a) of the tail pipe (69) is disposed in the second expansion chamber (C2). The exhaust structure for a vehicle according to claim 1 or 2, wherein the other end (69b) of the pipe (69) is opened to the outside air from a rear portion of the muffler (29). The exhaust structure for a vehicle according to any one of claims 1 to 3, wherein the catalyst (67) has a flat shape having a longitudinal direction as a width direction. The outer shape of the muffler (29) is higher in the height direction in which the tail pipe (69) is arranged than in the lateral width (W1) in the height direction position in which the connection pipe (68) and the catalyst (67) are arranged. The vehicle exhaust structure according to any one of claims 1 to 4, wherein the lateral width (W2) of the position is formed to be small. It has a cylindrical cover member (70) that covers a part of the tail pipe (69) from the outside in the radial direction, and the ends of the catalyst (67) and the connecting pipe (68) are connected to the inner wall of the muffler (29). The space between the cover member (70) and the tail pipe (69) facing each other communicates with the expansion chamber (C1) via a connection portion (72) between the cover member (70) and the inner wall. The exhaust structure for a vehicle according to any one of claims 1 to 5 , wherein: The vehicle according to claim 6, wherein the cover member (70) is connected to the muffler (29) by welding, and the connection part (73a) is formed in a tapered shape in a side view. Exhaust structure.

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