JPH11223124A - Exhaust system for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust system for a motorcycle to be taken in as one of appearance elements through emphasis of a line running from an exhaust pipe to a muffler, and bring a complicated exhaust system into a neat state, and improve appearance and a commercial value. SOLUTION: An exhaust system is formed such that exhaust pipes 13 and 14 running from a V-type engine are vertically juxtaposed on one side of a car body and the exhaust pipe is connected to a common exhaust chamber 16, and the exhaust chamber is connected to large silencers 18 and 19 in the rear of an exhaust pipe. The front end part of a lower silencer is positioned at the side along the direction of a car width of the exhaust chamber, and positioned at a side along the direction of a car width of a connection part between the silencer and the exhaust chamber. Exhaust covers 24 and 25 formed in the shape of an exhaust pipe connected to the front end of the silencer are arranged. The exhaust cover is formed such that a front end part communicating with the exhaust pipe is formed along the outer periphery of the exhaust pipe. The rear end part connected to the silencer is formed in a shape gradually enlarged such that the rear end part is sized to be equal to the outside of the front end part of the silencer.

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 equipped with a four-cycle engine.

[0002]

2. Description of the Related Art For example, in a motorcycle equipped with a V-type four-cycle engine, exhaust pipes derived from front and rear cylinders are connected to a common exhaust chamber in order to enhance engine output and muffling effect. , Two mufflers each having a cylindrical shape are connected to each other, and the exhaust gas from each cylinder is once led to an exhaust chamber and then distributed to both mufflers.

[0003] Recently, due to external design requirements, two silencers have been arranged one above the other on one side of the vehicle body, and the exhaust pipe of the rear cylinder has been guided to the side of the engine. There is a demand for guiding the exhaust pipe from the cylinder to the rear together with the exhaust pipe to emphasize the line flowing from the exhaust pipe to the muffler as one of the external elements.

[0004]

However, in the exhaust system provided with the exhaust chamber, since the exhaust chamber is installed at a position deep in the vehicle body, the rear part of the exhaust pipe connected to the exhaust chamber has: It must be bent toward the inside of the car body ahead of the silencer. Therefore,
Exhaust pipe handling became complicated, and it was extremely difficult to make the exhaust pipe and muffler a continuous design.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to emphasize a line from an exhaust pipe to a muffler, which is one of appearance elements. Another object of the present invention is to provide an exhaust system for a motorcycle having a complicated exhaust system that is clearly integrated and has improved appearance and commercial value.

[0006]

In order to achieve the above object, an exhaust system for a motorcycle according to the present invention includes a plurality of exhaust pipes derived from a V-shaped engine having front and rear cylinders, which are provided on one side of a vehicle body. Guide the exhaust pipe from the rear cylinder upward and the exhaust pipe from the front cylinder downward, and arrange them vertically one above the other, and bend the rear end of these exhaust pipes toward the inside of the vehicle body to form a common exhaust chamber. The exhaust device of the motorcycle is connected to the exhaust outlet of the exhaust chamber, and a plurality of cylindrical silencers having a diameter larger than that of the exhaust pipe arranged vertically above and behind the exhaust pipe. The front end of the lower silencer is located laterally along the vehicle width direction of the exhaust chamber, and is located laterally along the vehicle width direction of the connection between the silencer and the exhaust chamber. At the same time, on the outer circumference of each exhaust pipe, An exhaust cover shaped like an exhaust pipe is provided at the front end of the sounder. The exhaust cover is formed so that a front end connected to the exhaust pipe is formed along the outer periphery of the exhaust pipe. The silencer has a rear end portion having a shape gradually enlarged so as to be equal to the outer diameter of the front end portion of the silencer.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. In FIG. 8, reference numeral 1 denotes a frame constituting a vehicle body, and a main member 3 having a box-shaped cross section is connected to a steering head pipe 2 at a front end thereof. A four-cycle V-type two-cylinder engine 4 is suspended below the main member 3. The engine 4 has a front cylinder 6 and a rear cylinder 7 arranged on a crankcase 5 in a substantially V-shape in side view, and a carburetor 8 is arranged between the cylinders 6 and 7.
In FIG. 8, reference numeral 9 denotes a front fork, 10 denotes a frame cover which forms a fuel tank, and 11 denotes a sheet.

The engine 4 has a front cylinder 6 for front exhaust and a rear cylinder 7 for rear exhaust. Exhaust pipes 13 and 14 are led out from exhaust ports 12 of the cylinders 6 and 7, respectively. ing. The exhaust pipe 13 of the front cylinder 6 extends downward through the front of the crankcase 5, and its lower end is guided substantially horizontally rearward through the lower right side of the crankcase 5. Further, the exhaust pipe 14 of the rear cylinder 7 is led out to the right immediately after the exhaust port 12, and then is directed obliquely downward forward substantially in parallel with the axis of the rear cylinder 7, and is led to the right rear end of the crankcase 5. ing.

The exhaust pipe 14 is bent rearward on the right side of the crankcase 5 in a substantially U-shape.
Or the exhaust pipe 1 from the front cylinder 6 as shown in FIG.
3 are guided rearward, and both exhaust pipes 13,
The rear end portion 14 is bent toward the left side of the vehicle body in the crankcase 5.

A large-volume exhaust chamber 16 in the form of a flat tank is arranged in a portion facing the rear ends of the exhaust pipes 13 and 14, that is, in a space between the crankcase 5 and the rear wheel 15. The rear ends of the exhaust pipes 13 and 14 are welded to an exhaust inlet 17 provided on the upper surface of the exhaust chamber 16.

A pair of cylindrical silencers 18 and 19 are arranged behind the exhaust pipes 13 and 14. The silencers 18 and 19 extend in the front-rear direction in parallel with each other, and are arranged so as to overlap with each other vertically. The front ends thereof are closed by the front plate 20. The front ends of the silencers 18 and 19 are located on the right side of the exhaust chamber 16, and the exhaust inlet 2 is provided on the inner surface of the front end.
1, 21 are formed.

The exhaust inlets 21 and 21 and the exhaust outlet 22 provided on the upper surface of the exhaust chamber 16 are connected via a communication pipe 23, so that the exhaust from each of the cylinders 6 and 7 is After being once introduced into the exhaust chamber 16 via the exhaust pipes 13 and 14, it is distributed from here to both the silencers 18 and 19. The silencer 18,
The outer diameter of 19 is formed larger than the outer diameter of the exhaust pipes 13 and 14.

By the way, exhaust covers 24 and 25 made of sheet metal are attached to the outer periphery of the exhaust pipes 13 and 14 extending from the cylinders 6 and 7, respectively. Exhaust pipe 1 on the front side
As shown in FIGS. 4 and 6, the exhaust cover 24 is formed in a substantially semicircular cross section so as to cover the rear end of the exhaust pipe 13 from the outside by about a half circumference. After passing the side of the exhaust chamber 16, the lower silencer 18
It is extended with a smooth curve toward the front end. In addition, the curvature R of the exhaust cover 24 is gradually widened to be equal to the outer diameter of the front end thereof as it goes toward the rear silencer 18 side.
Has a shape like an exhaust pipe when viewed from the side.

In such an exhaust cover 24, the exhaust pipe 13 is press-fitted into a ring 26 welded to the inner periphery of the front end, and an end member 27 welded to the inner periphery of the rear end is butt-welded to the front plate 20. The exhaust pipe 13
And the exhaust silencer 18
The space between the silencer 3 and the silencer 18 is covered from the side.

On the other hand, the exhaust cover 25 of the rear exhaust pipe 14
Is formed over the entire length of the exhaust pipe 14, and is formed in a substantially semicircular cross section so as to cover a portion of the exhaust pipe 14 projecting to the right side of the vehicle body from the side. This exhaust cover 25
The rear end of the exhaust cover 24 is extended above the exhaust cover 24 in a smooth curve toward the front end of the upper silencer 19, and the curvature R of the rear end is equal to the one exhaust cover 24. In the same manner as described above, it is gradually widened toward the rear silencer 19 side. And this exhaust cover 25
The exhaust pipe 14 is inserted into the holding rings 29 and 30 welded to the inner circumference of the front end portion and the inner circumference of the middle portion, and the intermediate holding ring 30 and the exhaust pipe 14 are welded. The end member 31 welded to the muffler 1
By butt welding to the front plate 20 of No. 9,
It is integrated with the exhaust pipe 14 and the muffler 19, and covers a space between the exhaust pipe 14 and the muffler 19 from the side.

According to such a configuration, the exhaust pipes 13, 1
The exhaust covers 24 and 25 attached to the outer periphery of the exhaust pipe 1
Regardless of the bending direction of the rear end portions of the mufflers 3 and 14, they extend in a smooth curve toward the mufflers 18 and 19 at the rear, so that the exhaust pipes 13 and 14 and the mufflers 18 and 19 Despite the interposition of the exhaust chamber 16 between them, the appearance is obtained as if the two exhaust pipes 13 and 14 were directly connected to the mufflers 18 and 19. Therefore, the lines from the exhaust pipes 13 and 14 to the mufflers 18 and 19 can be emphasized as one of the appearance elements, which is convenient in design.

Further, the presence of the exhaust covers 24 and 25 also covers the connection between the exhaust pipes 13 and 14 and the exhaust chamber 16, so that a complicated exhaust system can be integrated and the appearance and commercial value can be improved. There are advantages too.

[0018]

According to the present invention described in detail above, the muffler having a relatively large diameter makes it difficult for the exhaust chamber disposed inside the muffler to be seen in a side view, and the exhaust cover allows the exhaust pipe to be formed. The appearance as if directly connected to the muffler is obtained, and the lines from these exhaust pipes to the muffler can be emphasized and incorporated as one of the appearance elements. In addition, there is also an advantage that the complicated exhaust system is clearly arranged and the appearance and commercial value are improved.

[Brief description of the drawings]

FIG. 1 is a side view of the entire exhaust device according to the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a side view showing a positional relationship among an exhaust pipe, an exhaust cover, and a muffler.

FIG. 4 is a plan view of an exhaust cover.

FIG. 5 is a sectional view taken along line VV in FIG. 3;

FIG. 6 is a sectional view taken along the line VI-VI in FIG.

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 2;

FIG. 8 is a side view of the motorcycle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body (frame) 4 Engine 13,14 Exhaust pipe 16 Exhaust chamber 18,19 Silencer 24,25 Exhaust cover

Claims (1)

[Claims] 1. A plurality of exhaust pipes derived from a V-type engine having front and rear cylinders are guided to one side of a vehicle body, and an exhaust pipe from a rear cylinder is upward and an exhaust pipe from a front cylinder is downward. These exhaust pipes are arranged vertically, and the rear ends of these exhaust pipes are bent toward the inside of the vehicle body and connected to a common exhaust chamber. At the exhaust outlet of this exhaust chamber, the exhaust pipes are stacked vertically behind the exhaust pipe. A motorcycle exhaust system in which a plurality of cylindrical silencers larger in diameter than the exhaust pipe arranged above are connected, wherein a front end of a lower silencer is a side along a vehicle width direction of an exhaust chamber. And at the side of the connecting portion between the silencer and the exhaust chamber along the vehicle width direction, and on the outer periphery of each exhaust pipe, an exhaust pipe shape continuous with the front end of the silencer is formed. A shaped exhaust cover is provided, and this exhaust cover
A shape in which a front end connected to the exhaust pipe is formed along the outer periphery of the exhaust pipe, and a rear end connected to the muffler is gradually enlarged so as to have the same outer diameter as the front end of the muffler. An exhaust device for a motorcycle, comprising: