JP2001073762A - Exhaust device of two-wheeled vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the center of gravity of radiator for a vehicle with exhaust pipe connected to the upper front part of cylinder of engine which is extended to rear side of vehicle body, by arranging the radiator in front of the connecting part of engine with exhaust pipe, and so forming the connecting part of engine with exhaust pipe by casting so as to bend sidewards. SOLUTION: At the water cooled engine for two-wheeled vehicle with off-road specification, supported by body frame, the exhaust system thereof is provided with exhaust tubes 23, 60, and front end part of which are connected to the outlet of cylinder. Each of exhaust tube 23, 60 are bent at a sharp angle after they stick out frontwards and extended backwards. Radiator, a constituent element of cooling system, is located in front of cylinder. On this occasion, the exhaust pipe 23 of left side sticks out frontwards farther than exhaust pipe 60 of right side, then, bends in U shape in approximately horizontal direction, and further rises upwards vertically, and front end part thereof is so arranged as to be connected to engine connection part 62 which is a casting with fitting flange 63.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for a motorcycle, and more particularly to a novel structure at an engine connecting portion of an exhaust pipe.

[0002]

2. Description of the Related Art In some cases, an exhaust pipe of a motorcycle is disposed rearward after being bent to the front of an engine. As for the engine connecting portion of such an exhaust pipe, Japanese Utility Model Laid-Open No. 63-16532 discloses an exhaust manifold for automobiles which is cast by a lost wax method.

[0003]

In some cases, the exhaust pipe of the engine must be brought close to the radiator due to the layout of the vehicle body. In such a case, if a normal pipe end such as a stainless steel pipe is used as it is as the engine connection part of the exhaust pipe, if this is bent too strongly, the radiator has no strength. Although raising the center of gravity and raising the center of gravity gives priority to exhaust efficiency, conversely, while lowering the radiator, the exhaust pipe has an unnatural bent shape,
The alternative is to give priority to the constant center of gravity over the exhaust efficiency.
Then, this invention aims at solving such a problem.

[0004]

According to the present invention, there is provided an exhaust system for a motorcycle according to the present invention, in which an engine is disposed substantially perpendicularly to a cylinder below a main pipe extending rearward from a head pipe. An exhaust pipe is connected to the upper front of the cylinder, and the motorcycle is disposed so as to extend from the front of the fly pipe to the rear of the vehicle body. Is formed by casting so as to bend the engine connection portion in the lateral direction.

[0005]

According to the present invention, since the engine connecting portion of the exhaust pipe is a cast bent member, one end of the engine connecting portion is provided in a narrow space between the radiator and the engine by disposing the radiator so as to be lowered to the front of the exhaust port of the engine. Is attached to the exhaust port of the engine, the other end is laterally protruded from this space, and connected to the end of the exhaust pipe with less bending. Thus, the center of gravity of the radiator can be reduced, and at the same time, since the engine connection portion of the exhaust pipe is a cast product, the exhaust pipe has sufficient strength so that the exhaust pipe can be connected to this position and the exhaust efficiency can be prevented from lowering. .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to the drawings. First, the overall structure of the vehicle body will be outlined with reference to FIG. The motorcycle is of an off-road type, and a front fork 3 is rotatably supported by a head pipe 2 provided at a front end of a body frame 1 and is steered by a handle 4. At the lower end of the front fork 3, a front wheel 5 is supported, and a front wheel brake device including a concentrically provided brake disc 6 and a brake caliper 7 is mounted.

The brake caliper 7 has a brake hose 8
Is connected to one end, and the other end is connected to a master cylinder 9 provided near a brake lever (not shown) of the handle 4. An intermediate portion of the brake hose 8 is disposed substantially along the front fork 3. Reference numeral 3a denotes an outer tube of the front fork 3, 3b denotes an inner tube, 10 denotes a headlight, 11 denotes a light case (small front cover) also serving as a bib number plate, and 12 denotes an instrument.

A fuel tank 15 is provided on the upper surface of the body frame 1.
Is supported, and the seat 16 is arranged behind the supporting member.
The seat 16 is supported on a seat rail 17 extending rearward from a rear shoulder of the body frame 1. The body frame 1 has a loop shape in a side view, and supports a water-cooled engine 18. A carburetor 20 is connected to the intake port of the water-cooled engine 18 from the rear of the cylinder 19, and the carburetor 20 is connected to the air cleaner 2 below the seat through a con tube 21.
2 is connected.

In the exhaust system, the front end of an exhaust pipe 23 is connected to the exhaust port of the cylinder 19, and the exhaust pipe 23 extends forward and then bends at a sharp angle to be the same as the intake system components such as the con tube 21. It extends rearward on the side up and down, and is connected to the muffler 24 at the rear of the vehicle body.

The cooling system is disposed in front of the cylinder 19 and is supplied from a radiator 25 supported on the vehicle body frame 1 to a water pump (not shown in the drawing) provided on a crankcase 26 of the water-cooled engine 18. Then, it is sent from here to the cylinder 19 to cool the cylinder 19. In addition,
A reserve tank 28 is housed in a skid plate 29 opposite to the crankcase 26.

The front side of the body frame 1 is formed into a loop by a main pipe 30, a pivot frame 31, a lower frame 32, a front down pipe 33, and the like. A front end of a swing arm 35 is pivotally supported by the pivot frame 31 so as to be swingable. This swing arm 35
A rear wheel 36 is supported at the rear end, a lower end of a rear cushion unit 37 is attached to a middle portion via a link, and the other end is extended upward and supported by the pivot frame 31.

Reference numeral 37a denotes a rear cushion unit 37.
The reservoir tank is provided at the upper end of the vehicle body, and is provided on the side opposite to the side where the con tube 21 and the exhaust pipe 23 of the vehicle body are provided, and projects to a position as if blocking passage of the exhaust pipe 23 and the like. I have. Reference numeral 34 denotes a side stand, which is rotatably attached to the lower end of the pivot frame 31.

In the lubrication system, a part of the vehicle body frame is used as an oil tank built in the frame, and oil is supplied to an oil pump of the crankcase 26.

Next, the configuration of the body frame 1 will be described in more detail. FIG. 2 shows a side shape of the body frame 1,
FIG. 3 shows the rear side. As is apparent from these figures, the vehicle body frame 1 is a pipe member that is disposed alone along the vehicle body center. The pivot frame 31 is divided into an upper half upper cross portion 40 and a lower half pivot plate portion 41, and the pivot plate portions 41 are further provided as a left and right pair.

The upper cross portion 40 is a cast product,
A neck portion 42 extends vertically along the center of the vehicle body and is welded at its upper end to a rear end portion of the main pipe 30, and an arm portion 43 protruding at the lower end portion thereof, which branches right and left. Neck 4
2, a boss 44 for mounting the seat rail 17 is provided on the rear portion.
A mounting boss 45 at the upper end of the rear cushion unit 37 provided below the boss is integrally formed.

The pivot plate portion 41 is a forged product having a large number of ribs formed on the inner surface, and its upper end 46 is fitted over the arm portion 43 from the side and welded and integrated at the contact surface. I have. A pivot portion 47 is provided at an intermediate portion of the pivot plate portion 41, where the swing arm 35 is supported, and a lower end portion 48 is a lower cross portion 49.
Are welded together from the side.

A mounting hole 50 for a stand bracket is formed on a side surface of the lower end portion 43. The lower cross portion 49 is, as shown in FIG.
The two rear ends are connected. Further, a cross plate 51 is provided above the lower cross portion 49 for connecting the intermediate portions of the left and right pivot plate portions 41 at an angle.

As shown in FIG. 3, the rear cushion unit 37 is vertically disposed with its upper end supported by a mounting boss 45, and its center is deviated leftward with respect to the vertical center line C of the vehicle body. Rank.

FIG. 4 is a view showing the lower frame 32 from below. The lower frame 32 has a rear end connected by a lower cross portion 49 and a front end side having a narrow width. Is connected to a joint member 52 provided at the lower end. Joint member 52
Is a member having a bifurcated lower portion, and a drain hole 53 is provided in the crotch portion.

The joint member 52 has a function as a member for closing the lower end of the front down pipe 33 which also serves as a built-in oil tank. Front down pipe 33
Constitutes a tank portion 54 integrally cast with the head pipe 2 using an aluminum alloy having excellent heat conductivity. A reinforcing pipe 55 connected to the main pipe 30 is connected to a rear portion of the tank 54.

A breather pipe 56 is provided at a connection between the upper part of the head pipe 2 and the front end of the main pipe 30, and is connected to the upper part of the cylinder 19 by a breather tube 57. Further, an oil return port is provided in the vicinity thereof, and an oil return pipe 58 is connected to the oil return pipe 58 from an oil pump below the crankcase 26.

FIG. 5 is a plan view of the exhaust pipe assembly, and FIG.
Shows the side view shape of the left exhaust pipe constituting this assembly. As shown in these drawings, the exhaust pipe assembly includes an exhaust pipe 23 on the left and an exhaust
To gather and guide the exhaust backward. That is, although the cylinder 19 is a single cylinder, it has two exhaust ports, and the left exhaust pipe 23 and the right exhaust pipe 60 are separately connected to these exhaust ports. The right exhaust pipe 60 is arranged on the left exhaust pipe 23 for layout reasons.
Significantly shorter.

As shown in FIG. 6, the exhaust pipe 23 extends from the rear to the front on the center side of the vehicle body with respect to the exhaust pipe 60 on the right side, once bends in a substantially horizontal direction in a U-turn shape, and further upwards. It rises substantially vertically, and its tip is connected to another engine connection part 62. The engine connecting portion 62 is a cast product, is bent in a substantially L-shape, and is integrally formed with a mounting flange 63 at a connecting end on the engine side. The other end of the engine connecting portion 62 is formed so as to face in the lateral direction when mounted (FIG. 5).

The exhaust pipe 23, the exhaust pipe 60, and the collective exhaust pipe 61 are all metal pipe members made of stainless steel or the like. When the connection is made, the strength is low due to restrictions on molding and fatigue due to use under high temperature and vibration. That is, the bent shape of the engine connecting portion 62 is such that it cannot be practically used with a conventional one.

A similar engine connecting portion 62 is attached to the tip of the collective exhaust pipe 61 as well. However, since this side is separated from the radiator radiator 25 and the cylinder cylinder 19 and can be connected with a relatively high degree of freedom, there is no need to bend so tightly. It is also possible.

Next, the operation of this embodiment will be described. As shown in FIG. 1, since the radiator 25 is located in front of the exhaust pipe 23 connection portion (exhaust port) of the cylinder 19, it is forced to bend sharply beyond the strength of the exhaust pipe 23 in a normal method. However, where connection in such a place is impossible, as shown in FIGS. 5 and 6, this problem has been solved by way of the engine connecting portion 62.

That is, the engine connecting portion 62 is a cast product, and the end portion on the exhaust pipe 23 side is bent laterally from the space between the radiator 25 and the cylinder 19 at the time of mounting.
The exhaust pipe 23 can be connected to the engine connecting portion 62 by such a bending that a normal pipe member can withstand sufficiently without being so strongly bent. Further, the engine connecting portion 62 has sufficient durability in this type of application as a cast product.

Accordingly, the radiator 25 can be maintained at a low center of gravity without sacrifice of the exhaust efficiency on the exhaust pipe 23 side. .

[Brief description of the drawings]

FIG. 1 is an overall side view of a motorcycle to which the present embodiment is applied.

FIG. 2 is a side view of a main part of the vehicle body frame.

FIG. 3 is a rear view thereof.

FIG. 4 is a bottom view thereof.

FIG. 5 is a plan view of an exhaust pipe assembly.

FIG. 6 is a side view of an exhaust pipe.

[Explanation of symbols]

18: engine, 19: cylinder, 23: exhaust pipe, 2
5: radiator, 60: exhaust pipe, 61: collective exhaust pipe, 6
2: engine connection, 63: mounting flange

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[Procedure amendment]

[Submission date] December 6, 1999 (1999.12.
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

TECHNICAL FIELD The present invention relates to an exhaust system of a motorcycle, in particular it relates to a new structure in an engine connection part of the exhaust pipe.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

[0003]

In some cases, the exhaust pipe of the engine must be brought close to the radiator due to the layout of the vehicle body. In such a case, if a normal pipe end such as a stainless steel pipe is used as it is as the engine connection part of the exhaust pipe, if this is bent too strongly, the radiator has no strength. Even if the center of gravity is raised by raising it, giving priority to exhaust efficiency, or conversely, lowering the radiator and making the exhaust pipe an unnatural bent shape,
It is an alternative to give priority to a low center of gravity over exhaust efficiency.
Then, this invention aims at solving such a problem.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

According to the present invention, there is provided an exhaust system for a motorcycle according to the present invention, in which an engine is disposed substantially perpendicularly to a cylinder below a main pipe extending rearward from a head pipe. connect the exhaust pipe to the upper front of the cylinder, the motorcycle is disposed to the exhaust pipe extending from the front of the engine to the rear of the vehicle body, thereby placing the radiator in the front exhaust pipe connecting portion of the engine, the exhaust The engine connecting portion of the pipe is formed by casting so as to bend in the lateral direction.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

The cooling system is disposed in front of the cylinder 19 and is supplied from a radiator 25 supported on the vehicle body frame 1 to a water pump (not shown in the drawing) provided on a crankcase 26 of the water-cooled engine 18. Then, it is sent from here to the cylinder 19 to cool the cylinder 19. In addition,
Reservoir 28 is housed between the crankcase 26 and skid plate 29.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

A mounting hole 50 for a stand bracket is formed on a side surface of the lower end portion 48 . The lower cross portion 49 is, as shown in FIG.
The two rear ends are connected. Further, a cross plate 51 is provided above the lower cross portion 49 for connecting the intermediate portions of the left and right pivot plate portions 41 at an angle.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

The joint member 52 has a function as a member for closing the lower end of the front down pipe 33 which also serves as a built-in oil tank. As shown in FIG. 2, the front down pipe 33 is formed of a tank portion 54 integrally cast with the head pipe 2 using an aluminum alloy having excellent heat conductivity.
Is composed. A reinforcing pipe 55 connected to the main pipe 30 is connected to a rear portion of the tank 54.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

The exhaust pipe 23, as shown in FIG. 6, been extended toward front than the right exhaust pipe 60, at a time substantially horizontal direction, returns bend U-turn shape, rising substantially vertically further upwards, The tip is connected to another engine connection part 62. The engine connecting portion 62 is a cast product, is bent in a substantially L-shape, and has a mounting flange 6 at the connecting end on the engine side.
3 are integrally formed. The other end of the engine connecting portion 62 is formed so as to face in the lateral direction when mounted (FIG. 5).

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

A similar engine connecting portion 62 is attached to the tip of the collective exhaust pipe 61 as well. However, since this side is separated from the radiator 25 and the cylinder 19, the connection can be made with a relatively high degree of freedom. Therefore, it is not necessary to bend so much, and the engine connection part 62 can be omitted and the connection can be made directly. It is possible.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0027

[Correction method] Change

[Correction contents]

That is, the engine connecting portion 62 is a cast product, and the end portion on the exhaust pipe 23 side is bent laterally from the space between the radiator 25 and the cylinder 19 at the time of mounting.
The exhaust pipe 23 without being forced to very tight bend, can be connected to the engine connection portion 62 by bending of the extent to which we well tolerated in normal pipe member. Further, the engine connecting portion 62 has sufficient durability in this type of application as a cast product.

[Procedure amendment 11]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 12]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

[Procedure amendment 13]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

[Procedure amendment 14]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

Claims (1)

[Claims] An engine is disposed with a cylinder substantially upright below a main pipe extending rearward from a head pipe,
An exhaust pipe is connected to an upper front part of a cylinder, and the exhaust pipe is arranged so as to extend from the front of the engine to the rear of the vehicle body. An exhaust device for a motorcycle, characterized in that the engine connection portion is formed by casting so as to be bent in a lateral direction.