JP4583439B2 - Motorcycle - Google Patents

Description

The present invention relates to a motorcycle, and more particularly to an advantageous arrangement structure of exhaust system parts.
In the present application, “up / down”, “front / rear”, and “left / right” are based on the state of the vehicle body facing forward in the traveling direction. Further, the inner side means the vehicle body center side, and the outer side means the opposite side. Further, the rearward tilt of the cylinder refers to a state in which the upper part of the cylinder is tilted backward in the vertical direction.

In a motorcycle using a front / rear V-type engine, the exhaust pipe on the front cylinder side extends downward from the front cylinder through the front thereof, extends downward from the crankcase, and extends downward from the rear cylinder through the rear thereof. In addition, the exhaust pipe on the rear cylinder side and the rear of the engine are assembled and connected to a muffler. The muffler extends to the upper side through the side of the rear wheel, and intake is performed from the V bank side between the front and rear cylinders. There is a thing (refer patent document 1).
In addition, the exhaust pipe that extends forward from the front of the cylinder of the forward leaning engine extends downward through the front of the cylinder, wraps around the lower part of the engine, and connects to a muffler located below the rear of the crankcase. Some are configured to take in air (see Patent Document 2).
Japanese Patent No. 2722097 Japanese Patent No. 3962012

As basic requirements for the body structure of a motorcycle, there is a concentration of mass and a low center of gravity. Since the intake system parts and the exhaust system parts are relatively heavy, there is a demand for the arrangement thereof. However, in the V-type engine vehicle as in the above-mentioned conventional example, exhaust system parts are dispersed back and forth, so it is difficult to concentrate the mass. Moreover, since the position of the muffler becomes high, it is difficult to lower the center of gravity.
Furthermore, in the forward lean engine vehicle, the mass is easy to move forward and the intake system parts are easy to move forward because of the simple arrangement that is substantially L-shaped when the exhaust pipe is passed through from the top to the bottom on the cylinder front. Since it is located above the back side of the cinder, the mass is still dispersed and it is difficult to lower the center of gravity. Moreover, the exhaust pipe length is shortened by arranging the muffler below the crankcase, which may cause a reduction in output.
Therefore, the present invention aims at concentrating mass and lowering the center of gravity more significantly than those of the conventional examples, and securing a necessary and sufficient exhaust pipe length.

In order to solve the above-mentioned problem, the invention according to claim 1 relating to a motorcycle is a motorcycle in which an engine is disposed between front and rear wheels, and an intake system component and an exhaust system component are connected to the front and rear of the cylinder, respectively.
The cylinder is tilted backwards, the intake port is provided in front of the engine and the exhaust port is provided in the rear of the engine.
An exhaust pipe connected to the exhaust port, extending sideways from the rear of the cylinder to the front of the cylinder, and extending rearward from the front of the cylinder through the lower part of the engine;
With this exhaust pipe and a muffler connected below the engine ,
In addition, an oil pan is provided below the crankcase of the engine, and this oil pan protrudes downward from the lower crankcase lower part.
The exhaust pipe extends from the exhaust port and bends forward immediately afterward, a second bend that bends forward at the front of the crankcase, and a third bend that bends downward from the front of the crankcase With
The front part of the oil pan is provided along the vertical direction at the front lower part of the crankcase,
The third bent portion is bent so as to go around the tip of the oil pan of the crankcase .

  According to a second aspect of the present invention, in the first aspect, the exhaust pipe is a portion that extends from the exhaust port toward the rear of the cylinder and then turns back to the side of the cylinder, and is divided into an exhaust upstream portion and an exhaust downstream portion. It is characterized by that.

Invention Oite to the claim 1 of claim 3, together with arranging the muffler between the rear wheel from the rear of the oil pan,
A mission part is formed behind the oil pan of the crankcase,
The bottom part of the part connecting the oil pan and the mission part is provided as a bottom inclined part that inclines upward toward the rear,
The portion below the bottom inclined portion of the exhaust pipe is arranged to be inclined upward and rearward along the bottom inclined portion in a side view .

  According to a fourth aspect of the present invention, in any one of the first to third aspects, an exhaust duct extending from a rear center of the muffler toward a vehicle body side is provided.

The invention of claim 5 is the exhaust system according to claim 4, wherein the exhaust duct is provided using a vehicle body cover, and is discharged sideways from a side opening formed in the vehicle body cover ,
A tail pipe is connected to the rear of the muffler,
The vehicle body cover covers the muffler,
The rear end portion of the vehicle body cover includes an extending portion that extends to the side of the rear wheel up to the center,
The side opening that opens to the side is formed at a position overlapping the rear wheel that is the base of the extension,
The tail pipe exhaust port faces this side opening,
Exhaust gas is discharged from the exhaust port to the outside of the vehicle body,
The extension portion has a substantially V-shaped cross section opened upward,
The tail pipe is inclined so that the lower side of the exhaust port is retracted inward of the vehicle body .

  According to the first aspect of the present invention, the cylinder is tilted rearward, the exhaust pipe that has come out to the rear of the cylinder is bent back, the side of the cylinder is obliquely crossed forward and downward, and then bent downward at the front of the cylinder. Since it is bent downward and connected to the muffler located below the crankcase, it is possible to concentrate the mass by arranging the exhaust pipe so as to be wound around the rearward tilted cylinder. Can be centered. Moreover, the exhaust pipe length which is concerned by arranging the muffler below the crankcase can eliminate the above concerns by arranging the exhaust pipe so as to tilt and wrap around the cylinder, ensuring a necessary and sufficient length, The engine output can be improved.

According to the invention of claim 2, despite employing more structures bend in the exhaust pipe, the portion folded back thereafter cylinder side extending toward the cylinder backward from the exhaust port, exhaust downstream side and the exhaust upstream portion Since the exhaust gas is divided into the parts, the exhaust upstream side part and the exhaust downstream side part can be easily manufactured, the assembly is facilitated, and the assembling property is improved.

  According to the third aspect of the present invention, the oil pan is provided below the crankcase of the engine, and the oil pan protrudes downward from the lower crankcase lower portion. A space for placing the muffler is secured and the muffler can be placed here. Therefore, by arranging the muffler at the lowest position of the engine, the center of gravity can be lowered and the muffler can be arranged close to the center of gravity of the engine, so that the mass can be concentrated.

  According to the invention of claim 4, even if the muffler is disposed in front of the rear wheel, the exhaust duct can exhaust the air toward the vehicle body side while avoiding the rear wheel.

According to the fifth aspect of the present invention, the exhaust duct can be provided by using the vehicle body cover, and the air can be exhausted laterally from the side opening formed on the side surface of the vehicle body cover.

  An embodiment will be described below with reference to the drawings. FIG. 1 is an external side view of the motorcycle with a vehicle body cover mounted thereon, and FIG. 2 is a side view of the main part of the vehicle body showing a part of external parts such as the vehicle body cover as imaginary lines. In these drawings, reference numeral 1 denotes a front wheel which is rotatably supported by a head pipe 3 via a front fork 2 and is steered by a handle 4.

  The head pipe 3 is provided at the front end of the vehicle body frame 5, and a fuel tank 7 is supported on a main frame 6 that extends rearward obliquely downward, and an engine 8 is supported below. A lower protrusion 7b is formed at the rear of the bottom surface 7a of the fuel tank 7, and a built-in fuel pump (not shown) is attached. A space for accommodating the lower protrusion 7 b is formed behind the cylinder 10 and above the main frame 6.

The engine 8 includes a crankcase 9 and a cylinder 10 tilted rearward thereon. The crankcase 9 has an oil pan 9a that protrudes downward most greatly at the front lower portion, and a mission portion 9b is formed behind the oil pan 9a. The ground clearance at the lower surface of the mission unit 9b is higher than that of the oil pan 9a.
The transmission 9b is stepped higher than the oil pan 9a of the crankcase 9, and a relatively large diameter and large capacity muffler 20 is located below the transmission 9b.

The cylinder 10 is located below the fuel tank 7, and the upper part of the cylinder 10 is close to the bottom surface of the fuel tank 7.
An intake box 11 is located in front of the cylinder 10. The intake box 11 is sandwiched between a radiator 12 positioned in front of the intake box 11 and the cylinder 10, and the upper end of the intake box 11 is fixed to the bottom surface of the fuel tank 7. An intake duct 13 is provided at the upper part of the intake box 11, and a wind guide port 14 at the tip of the intake box 11 projects forward from the upper side of the radiator 12, and the traveling wind W (see FIGS. 1 to 3) is forwarded from the front of the radiator 12 into the intake box 11. To import. The radiator 12 has an upper portion supported by the main frame 6 and a lower portion supported by a stay 9 c protruding from the front surface of the crankcase 9.

  An intake funnel 15 and a simplified throttle body 16 are accommodated in the intake box 11. The intake funnel 15 is arranged in the vertical direction so that the diagonally upward direction extends obliquely upward and is connected to an intake port 17 formed on the front surface of the cylinder 10 so as to face upward. It is supposed to be.

  An exhaust port 18 directed rearward is provided on the back side of the cylinder 10, and is discharged from here through an exhaust pipe 19. The exhaust pipe 19 once extends to the rear, bends approximately 180 ° immediately after that, extends obliquely forward and downward, exits to the front of the crankcase 9, bends downward, extends downward along its front surface, and further to the rear It bends and goes around below the crankcase 9 and connects to the muffler 20 arranged below the mission portion 9b. Exhaust gas that has entered the muffler 20 is discharged to the outside air from a tail pipe 21 connected to the rear of the muffler 20. The tail pipe 21 is bent by approximately 90 °, and the exhaust port 21a at the exhaust downstream side tip opens sideways.

  Below the mission unit 9b is one step higher than the oil pan 9a, and a space for arranging a muffler between the oil pan 9a and the rear rear wheel 31 is secured below the mission pan 9a. Therefore, the muffler 20 having a relatively large diameter and a large capacity can be disposed in this space. As a result, the center of gravity can be lowered by arranging the muffler 20 at the lowest position of the engine 8 with a minimum ground clearance equivalent to that of the oil pan 9a below the muffler 20. Since the muffler 20 can be arranged close to the center of gravity of 8, the mass can be concentrated.

  A center frame 22 extending in the up-down direction is connected to the rear end portion of the main frame 6, and a column 23 is provided that protrudes obliquely upward from the upper end portion. From the upper end of the support column 23, a seat rail 24 that extends obliquely and extends rearward is provided, and the rear end portion of the fuel tank 7 and the seat 25 are supported here. Reference numeral 26 denotes a rear stay that connects the lower portion of the column 23 and the seat rail 24. The center frame 22, the support column 23, the seat rail 24, and the rear stay 26 are provided in a pair of left and right.

  The center frame 22 extends obliquely up and down along the rear part of the transmission part 9b which is the rear part of the crankcase 9, and the front end part of the rear arm 28 is supported by the pivot part 27 at the middle part in the vertical direction. The front part of the rear arm 28 is connected to the column 23 by a rear cushion 30 via a link 29 provided at the lower part.

  A rear wheel 31 is supported at the rear end of the rear arm 28 and is driven by a drive sprocket 8 a of the engine 8 via a chain 32. 31a is a rear wheel axle, and 31b is a driven sprocket.

The exhaust pipe 19 extends from the exhaust port 18 and bends forward immediately afterward, a second bent portion 19b that bends forward of the crankcase 9 downward, and bends downward from the front of the crankcase 9 downward. A third bent portion 19c is provided. The third bent portion 19 c is bent so as to go around the tip of the oil pan 9 a of the crankcase 9. As described above, the exhaust pipe 19 is formed so as to wind around the cylinder 10 in a substantially S-shape when viewed from the side, so that the mass is concentrated concentrically and is necessary and sufficient for improving the output in combination with the backward tilt of the cylinder 10. Realizes a long exhaust pipe length. The degree of backward tilting of the cylinder 10 is arbitrarily determined according to the required exhaust pipe length, but the exhaust pipe length can be increased as the cylinder is tilted backward compared to the upright position.

  The car body is covered with a car body cover. The vehicle body cover includes an upper cover 33 that covers the radiator 12, the intake box 11, and the side of the cylinder 10 from the front of the head pipe 3, and a lower cover 34 that covers the lower side surface of the engine 8 below the radiator 12. The upper cover 33 and the lower cover 34 are divided into upper and lower portions on a side surface of the vehicle body, with a dividing line obliquely descending forward.

  The lower cover 34 covers exhaust system components below the vicinity of the second bent portion 19b of the exhaust pipe 19. The rear end portion of the lower cover 34 is provided with an extending portion 35 that extends to the side surface of the rear wheel 31 to the vicinity of the center, and a side surface opening portion that opens laterally at a position overlapping the rear wheel 31 that is the base portion of the extending portion 35 36 is formed, and the exhaust port 21a of the tail pipe 21 faces here, and the exhaust is discharged to the outside of the vehicle body from here.

  A step 37 is located above the extending portion 35. The step 37 is provided at the rear end of the step holder 38 that protrudes rearward from the center frame 22 in a substantially V shape. The exhaust port 21a is located below the step 37, and the exhaust port 21a is open outward and obliquely upward.

  FIG. 3 is a plan view of the main part. The main frame 6 is provided in a pair of left and right that expands and extends rearward from the head pipe 3. Although not visible in this figure, a pair of left and right seat rails 24 and rear stays 26 are also provided. The intake box 11 has a front side that is as wide as the distance between the left and right front forks 2 and a rear side that is gradually narrowed in the left and right width. The intake duct 13 extends forward over the radiator 12 and introduces traveling wind from an air guide port 14 located behind the front fork 2.

The rear wall of the intake box 11 overlaps the front surface of the cylinder 10, the intake port of the cylinder 10 overlaps the lower portion of the rear wall, and the lower end portion of the intake funnel 15 is connected to the intake port 17.
The radiator 12 is arranged transversely in the vehicle width direction (left-right direction), and the middle part in the left-right direction forms a curved surface that protrudes most rearward.

  An exhaust upstream end 19d connected to the exhaust port 18 of the exhaust pipe 19 is located in the vicinity of the vehicle body center C (slightly toward the right side), and the space between the first bent portion 19a and the second bent portion 19b is rearward and forward. Toward the vehicle body center C from the second bent portion 19b, the third bent portion 19c is located on the vehicle center C, and then along the vehicle center C, Connect to the muffler 20 located on the center C.

  FIG. 4 is a plan view of the vehicle body main frame 6 portion. The head pipe 3 is integrally provided at a front end portion of a substantially V-shaped head portion 40 that expands rearward in a plan view. The head 40 is formed by light alloy casting or forging. The front end portions of the left and right square pipe portions 42 are connected to the arm portions 41 extending to the left and right rear, and the space 44 surrounded by the arm portions 41 and the square pipe portions 42 and the back wall 43 of the head portion 40. An intake box 11 (FIG. 1) is accommodated. At this time, the periphery of the upper end portion of the intake box 11 overlaps the upper surfaces of the arm portions 41 and the square pipe portions 42 and the upper surface of the rear wall 43 and the upper rear portion of the cross portion 45 that is the rear of the head pipe 3.

  FIG. 5 is a perspective view showing the arrangement of intake system components and exhaust system components. The intake box 11 is housed on the lower half side of the main body 46 in a space formed between the radiator 12 tilted forward and the cylinder 10, and the intake duct 13 protrudes above the radiator 12 and forwards the radiator 12. A stay 47 that protrudes and extends through the intake duct 13 and extends from the upper surface of the radiator 12 protrudes upward to support the upper end portion on the lower surface of the main frame 6.

The exhaust pipe 19 has a first bent portion 19a curved in a space formed between the back surface of the cylinder 10 and the upper surface of the transmission portion 9b of the crankcase 9, and the side surface of the engine 8 is connected to the connecting portion between the cylinder 10 and the crankcase 9. The second bent portion 19b enters the space formed between the lower end of the radiator 12 and the lower front portion of the oil pan 9a, and enters the lower portion of the crankcase 9 at the third bent portion 19c. It is arranged using a gap formed between the parts.
The first bent portion 19a is substantially U-shaped in a plan view and a side view and bends into a three-dimensional shape, and the portion toward the second bent portion 19b after the 19e that wraps around the side surface of the cylinder 10 is the cylinder. The bent portion 19e is also a part of the first bent portion 19a.

  FIG. 6 is a view showing the engine 8 from the front, and a lower portion of the right case 9R of the crankcase 9 is omitted. 9L is the left case. The second bent portion 19b is positioned so as to protrude further outward than the maximum lateral protrusion of the left case 9L of the crankcase 9. A portion from the second bent portion 19b to the third bent portion 19c is arranged in an oblique manner from the upper second bent portion 19b to the lower third bent portion 19c in a substantially straight line toward the vehicle body center side. The bent portion 19c and the muffler 20 are located on the vehicle body center C. This inclination is close to the side inclination of the extending portion 35 that substantially forms a bank angle. The opening edge 21c of the tail pipe 21 is an obliquely cut line so that the lower side approaches the vehicle body center C in front view.

The exhaust pipe 19 is divided into an upper portion 50 that is an exhaust upstream portion from the first bent portion 19a to the second bent portion 19b, and a lower portion 60 that is an exhaust downstream portion from the second bent portion 19b to the muffler 20. It is detachably connected in the vicinity of the second bent portion 19b. Reference numeral 19f denotes a dividing line. Thus, by dividing the vicinity of the second bent portion 19b and on the first bent portion 19a side, the upper portion 50 and the lower portion 60 that bend substantially in the opposite direction are adopted even though the exhaust pipe 19 employs a structure having many bends. Since each of these exhaust pipes can be manufactured easily because they can be manufactured separately, a dividing line 19f is provided in a substantially straight line portion between the first bent portion 19a and the second bent portion 19b and is connected here so that assembly is also easy. Become.

  Hereinafter, details of each part of the exhaust pipe 19 will be described. The exhaust pipe 19 is assembled by connecting a plurality of divided metal pipes. 7 is a side view of the upper part 50, and FIG. 8 is a plan view. The upper part 50 is composed of three parts of a first pipe 51, a second pipe 52 and a third pipe 53 in order from the exhaust upstream side, and these parts are connected and integrated by welding.

  The first pipe 51 is provided with a mounting flange 54 in the vicinity of the connection end 19 d with the exhaust port 18. The first pipe 51 is bent in a semicircular shape so as to protrude rearward in a substantially semicircular shape in FIG. 7, and as shown in FIG. 8, the exhaust pipe downstream end of the first pipe 51 is bent back to a position overlapping the vicinity of the mounting flange 54. ing. The exhaust pipe downstream end of the first pipe 51 extends outward and obliquely downward (FIG. 8).

  The second pipe 52 is a relatively short pipe, and both ends of the exhaust upstream side and the exhaust downstream side overlap the exhaust downstream end of the first pipe 51 and the exhaust upstream end of the third pipe 53, and are welded. Integrated. Reference numerals 56 and 57 denote welding lines. The second pipe 52 extends in the extending direction of the extending direction of the end portion on the exhaust downstream side of the first pipe 51.

  The third pipe 53 has a bent end 19e at the upstream end of the exhaust, and the upstream side of the third pipe 53 is bent inward and obliquely upward (FIG. 7), and is connected to the exhaust downstream end of the second pipe 52 and welded. The The downstream side of the exhaust pipe from the bent portion 19e of the third pipe 53 is inclined substantially straightly downward (FIG. 7) and slightly opened outward (FIG. 8).

As described above, by forming a three-part structure of the first pipe 51, the second pipe 52, and the third pipe 53, the pipe-shaped upper portion 50 having a relatively strong bend can be configured. 58 provided on the side face of the third pipe 53, a spring hook hook for pulling the connecting portion by a spring.

  9 shows a side view of the lower portion 60, the muffler 20 and the tail pipe 21, and FIG. 10 shows a plan view thereof. The lower portion 60 is divided into a first pipe 61, a second pipe 62, a third pipe 63, and a fourth pipe 64 in order from the exhaust upstream side, and the respective portions are connected and integrated by welding.

The first pipe 61 bends in a substantially U shape in side view at the second bent portion 19 b (FIG. 9 ), and the exhaust upstream side end portion 65 at the second bent portion 19 b in the plan view is downstream of the third pipe 53. Plugged into the side edge. Reference numeral 61a denotes a tension spring locking hook (FIG. 10). A bracket 66 is provided in the vicinity of the second bent portion 19b, and is connected to and supported by a stay 9c protruding from the crankcase (FIG. 2).

  The second pipe 62 is formed as a tapered pipe that gradually increases in diameter toward the exhaust downstream side. The second pipe 62 is disposed obliquely so that the exhaust downstream side is inward of the vehicle body when viewed from the side and in plan view. The downstream end is welded to the exhaust downstream end of the first pipe 61 and the exhaust upstream end of the third pipe 63. 67 and 68 are welding lines.

The third pipe 63 is bent at the third bent portion 19c so as to face from the upper side to the rear side when viewed from the side, and is bent toward the rear side from the state extending laterally from the outer side toward the inner side when viewed from above.
The fourth pipe 64 is welded to the exhaust downstream end of the third pipe 63 at the exhaust upstream end. Reference numeral 69 denotes a welding line.
The exhaust pipe downstream side of the fourth pipe 64 is a tapered pipe welded to the exhaust upstream side end portion of the inner pipe 70 that gradually expands in diameter and constitutes the muffler 20. 71 is a welding line. Thus, by dividing the lower portion 60 into the first pipe 61 to the fourth pipe 64, a complicated shape including the second bent portion 19b and the third bent portion 19c can be easily realized.

  The muffler 20 is a silencer having a double pipe structure including an inner pipe 70 and an outer pipe 72. The inner pipe 70 includes an oblique front part 70a which is an extension part of the fourth pipe 64, and a straight part 70b which is bent from the front part 70a and extends horizontally. It is formed by winding a metal mesh around. A known sound absorbing material 73 such as glass wool is filled between the inner pipe 70 and the outer pipe 72.

The outer pipe 72 includes a front cone portion 74 that covers the front portion 70a of the inner pipe 70 and has a tapered peripheral wall, a center portion 75 that covers the straight portion 70b in parallel, a rear end thereof, and a straight portion of the inner pipe 70. And a rear portion 76 serving as a spacer for concentrically supporting the exhaust downstream side end portion in 70 b into the center portion 75.
As is apparent from FIG. 2, the front cone portion 74 has a substantially truncated cone shape having an inclined surface that swells forward, and the inclined surface is substantially parallel to the bottom inclined portion 9 d provided at the bottom of the crankcase 9. This also allows the muffler 20 to approach the engine (crankcase bottom) and contributes to mass concentration. The bottom inclined portion 9d is a bottom portion that connects the oil pan 9a and the mission portion 9b, and is inclined upward toward the rear.

  The connection between the front cone portion 74 and the center portion 75 and the connection between the center portion 75 and the rear portion 76 are performed by overlapping each other and connecting with rivets. The exhaust upstream end of the tail pipe 21 surrounds the exhaust downstream end of the straight portion 70 b of the inner pipe 70 and is welded to the rear portion 76. Reference numeral 77 denotes a stay for supporting the muffler 20 to the vehicle body frame.

  In the plan view, the tail pipe 21 is bent laterally at the bent portion 21b at the intermediate portion, and is opened laterally. The opening 21a is elliptically arranged and inclined obliquely upward. Concave portions 78a and 78b are formed on the outer surface near the bent portion 21b.

  FIG. 11 is a plan view showing the piping of the tail pipe 21, and the muffler 20 and the tail pipe 21 are accommodated in a space 35 a having a tunnel shape of the lower cover 34, and the tail pipe 21 extends at the rear end portion of the lower cover 34. An exhaust port 21 a of the tail pipe 21 faces a side opening 36 formed on one side surface of the protruding portion 35. In this way, the exhaust can be discharged outward from the extending portion 35 of the lower cover 34. That is, the extending part 35 forms an exhaust duct together with the tail pipe 21, and is discharged outward through the side opening 36 and the exhaust port 21a.

  FIG. 12 is a cross section taken along line 12-12 of FIG. 11, and the extending portion 35 has a substantially V-shaped cross section opened upward, and the tail pipe 21 is reversed so that the lower side of the exhaust port 21a is retracted inward of the vehicle body. In other words, the upper side is inclined so as to project outward, and the exhaust direction is directed obliquely downward so as to prevent the outward and upward flow, and the exhaust is discharged outward.

  FIG. 13 shows a variation of the side opening, and the rear end of the tail pipe 21 has an exhaust port 21a that extends straight and opens on the center of the vehicle body. A guide wall 80 having a substantially V-shape projecting forward is formed behind the exhaust port 21a, and side opening portions 36 are formed on the left and right side walls of the extending portion 3, respectively. The space 35a in the extending portion 35 is closed around the tail pipe 21 by a partition wall 81 having an inclination parallel to the guide wall 80, and the exhaust passage 82 extends from the exhaust port 21a toward the left and right side openings 36. It is branched and formed.

  In this way, the exhaust discharged from the exhaust port 21a along the vehicle body center C is separated into the right and left by the guide wall 80 and branched to the right and left through the exhaust passage 82. It is discharged rearward on the center of the vehicle body and quickly discharged to the outside from the left and right side openings 36. In addition, since the tail pipe 21 is not bent, the exhaust flow can be made smooth to improve the exhaust efficiency. Further, the exhaust duct 82 is formed by the exhaust passage 82 formed in the extending portion 35 and is discharged to the left and right outer sides through the side opening portions 36 on both the left and right sides.

  Next, the operation of this embodiment will be described. As shown in FIGS. 2 and 5, the cylinder 10 is tilted rearward, the exhaust pipe 19 that has come out to the rear of the cylinder 10 is bent back, and the left side of the cylinder 10 is obliquely crossed forward and downward. Since it is bent forward and bent to wind an oil pan 9a protruding downward at the front of the crankcase 9, and connected to the muffler 20 disposed below the transmission 9b of the crankcase 9, the exhaust pipe 19 Is arranged so as to be wound around the cylinder 10 tilted backward, so that the mass can be concentrated, and the center of gravity can be lowered by arranging the muffler 20 below the crankcase. In addition, the exhaust pipe length which is concerned by disposing the muffler 20 below the transmission part 9b of the crankcase 9 is necessary to eliminate the above concerns by arranging the exhaust pipe 19 so that the cylinder 10 is inclined backward and wound. Sufficient length can be secured and engine output can be improved.

Further, as shown in FIGS. 3 and 7 to 10, in spite of adopting a structure with many bends in the exhaust pipe 19, it extends from the exhaust port 18 toward the rear of the cylinder 10 and then turns back to the side of the cylinder. Since the upper part 50 that is the exhaust upstream side part and the lower part 60 that is the exhaust downstream side part are divided, the tightly bent parts can be distributed to the upper part 50 and the lower part 60 and manufactured separately, which facilitates manufacture. Furthermore, since it can assemble only by connecting the upper part 50 and the lower part 60 with the division line 19f, an assembly becomes easy and an assembly property improves.

  Further, as shown in FIG. 2, an oil pan 9a is provided below the crankcase 9 of the engine 8, and this oil pan 9a protrudes downward from the mission portion 9b which is the lower crankcase lower portion. A space for disposing the muffler 20 between the rear of the oil pan 9a and the rear wheel 31 can be secured below the mission portion 9b, and the muffler 20 can be disposed here. Therefore, by arranging the muffler 20 at the lowest position of the engine 8, the center of gravity can be lowered, and the muffler 20 can be disposed close to the approximate center of the crankcase 9 where the center of gravity of the engine 8 is located. The mass can be concentrated.

Further, as shown in FIGS. 3 and 11 to 13, even when the muffler 20 is disposed in front of the rear wheel 31, the side surface of the extension portion is extended from the tail pipe 21 corresponding to the exhaust duct and the exhaust passage of the extension portion 35. It is possible to exhaust the exhaust toward the outside of the vehicle body by avoiding the rear wheel 31 from the side opening 36 provided in the vehicle.
At this time, the side opening 36 can be provided on either the left or right side or both the left and right sides of the extension 35. When the side opening 36 is provided on one side, the exhaust duct can be easily formed simply by bending the tail pipe 21 to the side. . Moreover, when providing in both side surfaces, the exhaust duct can be formed by forming the exhaust passage branched to right and left in the extension part 35.

External side view of motorcycle according to embodiment Plan view of the main part above Side view of the main part of the motorcycle Plan view of main parts of body frame Perspective view showing the arrangement of intake system parts and exhaust system parts obliquely from the rear Diagram showing the front view of the engine Side view of the upper part of the exhaust pipe Plan view of the above part Side view related to the lower part of the exhaust pipe Plan view of the above part Top view showing the arrangement of the tailpipe Sectional drawing which follows the 12-12 line of FIG. The figure which shows the variation of FIG.

Explanation of symbols

8: Engine, 9: Crankcase, 9a: Oil pan, 9b: Mission part, 19: Exhaust pipe, 19a: First bent part, 19b: Second bent part, 19c: Third bent part, 20: Muffler

Claims (6)

In a motorcycle in which an engine (8) having a cylinder (10) and a crankcase (9) is arranged between the front and rear wheels, and an intake system component and an exhaust system component are connected to the front and rear of the cylinder (10) , respectively.
The cylinder (10) is tilted backward, the intake port (17) is provided at the front of the cylinder, and the exhaust port (18) is provided at the rear of the cylinder.
Connected to the exhaust port (18), a cylinder (10) extending from the rear as the cylinder forward side, an exhaust pipe extending rearward through the crankcase (9) downward from the cylinder front (19),
The exhaust pipe (19) and a muffler (20) connected below the crankcase are provided,
Furthermore, an oil pan (9a) is provided below the crankcase of the engine (8), and the oil pan (9a) protrudes downward from the lower crankcase lower part thereof,
The exhaust pipe (19) extends from the exhaust port (18) and bends immediately after the first bend (19a), and the second bend (19b) bends the front of the crankcase (9) downward. A third bent portion (19c) that bends downward from the front of the crankcase (9),
The front part of the oil pan (9a) is provided along the vertical direction at the front lower part of the crankcase (9),
The motorcycle is characterized in that the third bent portion (19c) is bent so as to go around the tip of the oil pan (9a) of the crankcase (9) . The automatic exhaust pipe according to claim 1, wherein the exhaust pipe is divided into an exhaust upstream portion and an exhaust downstream portion at a portion extending from the exhaust port toward the rear of the cylinder and then turning back to the cylinder side. Two-wheeled vehicle. While arranging the muffler (20) between the rear wheels from the rear of the oil pan (9a) ,
A mission part (9b) is formed behind the oil pan (9a) of the crankcase (9),
The bottom part of the portion connecting the oil pan (9a) and the mission part (9b) is provided as a bottom slope part (9d) that slopes upward toward the rear,
The automatic exhaust pipe as set forth in claim 1, wherein a portion of the exhaust pipe (19) below the bottom inclined portion is disposed to be inclined upward and rearward along the bottom inclined portion in a side view. Two-wheeled vehicle. The motorcycle according to any one of claims 1 to 3, further comprising an exhaust duct extending from a rear center of the muffler toward a side of the vehicle body. The exhaust duct is provided using a vehicle body cover, and is exhausted laterally from a side opening (36) formed in the vehicle body cover,
A tail pipe (21) is connected to the rear of the muffler (20),
The vehicle body cover (34) covers the muffler,
The rear end portion of the vehicle body cover (34) includes an extending portion (35) extending to the side surface of the rear wheel (31) to the vicinity of the center,
The side opening (36) opened sideways is formed at a position overlapping the rear wheel (31) which is the base of the extension (35),
The exhaust opening (21a) of the tail pipe (21) faces this side opening,
Exhaust gas is discharged from the exhaust port (21a) to the outside of the vehicle body,
The extension part (35) has a substantially V-shaped cross section opened upward,
The motorcycle according to claim 4, wherein the lower side of the exhaust port (21a) of the tail pipe (21) is inclined so as to recede toward the inside of the vehicle body . The motorcycle according to claim 1, wherein a part (19) of the first bent portion of the exhaust pipe overlaps the engine in a plan view.

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