JPH08200041A - Exhaust system for motorcycle - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an exhaust system for a motorcycle, which can improve strength with a simple structure, and which can improve the appearance of the muffler by covering the welded portion. [Structure] In an exhaust system of a motorcycle in which an exhaust pipe 25 is connected to an engine 17 mounted on a vehicle body, and a muffler 26 is connected to the exhaust pipe 25, an exhaust gas is exhausted inside a rear end opening 50a of an outer cylinder 50 of the muffler 26. An inner cap 81 that supports an exhaust pipe 64 that discharges gas to the atmosphere is inserted and welded,
The outer cap 84 is attached to the inner cap 81 by a fastening means, and the outer peripheral end surface 84a of the outer cap 84 is flush with the rear end opening end surface 50e of the outer cylinder 50 to cover the inner cap 81. There is.

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 muffler.

[0002]

2. Description of the Related Art In some motorcycles, an exhaust pipe is connected to an engine mounted on a vehicle body, and a muffler is connected to the exhaust pipe. At the rear end opening of the outer cylinder of this muffler,
There is one in which a cap is inserted and welded inside the rear end opening, and the cap supports an exhaust pipe for discharging exhaust gas to the atmosphere.

[0003]

As described above, the cap is welded and attached to the rear end opening of the outer cylinder of the muffler. Particularly, the cap is required to have strength against exhaust pressure. Also, the welded part of the cap has a raised bead and is discolored black due to the heat during welding. Especially, in motorcycles, the welded part of the rear end opening of the muffler can be seen from the outside, which is not desirable in appearance. .

The present invention has been made in view of the above circumstances, and provides a motorcycle exhaust system capable of improving strength with a simple structure and further improving the appearance of the muffler by covering the welded portion. It is an object.

[0005]

In order to solve the above problems and to achieve the object, the invention of claim 1 connects an exhaust pipe to an engine mounted on a vehicle body, and connects a muffler to the exhaust pipe. In an exhaust system for motorcycles, an inner cap that supports an exhaust pipe that discharges exhaust gas to the atmosphere is inserted and welded inside the rear end opening of the outer cylinder of the muffler, and the outer cap is fastened to this inner cap. It is characterized in that the outer cap is attached by an attaching means, and the outer peripheral end surface of the outer cap is flush with the rear end opening end surface of the outer cylinder to cover the inner cap.

[0006]

According to the first aspect of the present invention, the inner cap is inserted and welded inside the rear end opening of the outer cylinder of the muffler, and the outer cap is attached to the inner cap by the tightening means. Assembling with the outer cap improves the strength. Also, the outer peripheral end face of the outer cap is flush with the rear end opening end face of the outer cylinder to cover the inner cap, and the welded portion of the rear end opening of the muffler cannot be seen from the outside, and with a simple structure, The muffler looks good.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An exhaust system for a motorcycle according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a side view of the motorcycle, FIG. 2 is a plan view of the motorcycle, FIG. 3 is a front view of the motorcycle, and FIG. 4 is a rear view of the motorcycle.

A vehicle body frame 1 of a motorcycle has a truss main frame 2 assembled with a number of frames 2a, and a head pipe 3 is provided on the front side of the truss main frame 2. A front fork 4 is provided on the head pipe 3, a front wheel 5 is supported on a lower portion of the front fake 4, and a handle 6 is attached on an upper portion thereof.

A rear arm bracket 7 is connected to the rear side of the truss main frame 2. A seat rail 8 is connected to the truss main frame 2 at a position from the center to the rear, and the seat rail 8 is connected to the rear frame 9
Supported by From the truss mainframe 2
A fuel tank 10 is arranged on the front side of the seat rail 8,
A tandem seat 11 is arranged behind the fuel tank 10 as a seat, and the tandem seat 11 is composed of a tandem front seat 11a and a tandem rear seat 11b.

The rear cowl 12 covers the lower part of the tandem seat 11 from the both sides behind the rear part. A front cowl 13 covers the periphery of the head pipe 3 from the front side of the truss main frame 2.

A rear arm bracket 7 provided at the rear of the truss main frame 2 supports a rear arm 15 so as to be vertically swingable via a pivot shaft 14, and a rear wheel 16 is provided on the rear arm 15. .

An engine 17 is supported on the truss main frame 2 and the rear arm bracket 7, and the engine 17 has two parallel cylinders. The cylinder 18 of the engine 17 is arranged so as to be tilted to the front side, and the cylinder 18 is attached to and supported by the truss main frame 2, and the crankcase 19 of the engine 17 is attached via the mounting brackets 20 and 21 to the truss main frame 2 and the rear arm bracket. It is supported by 7.

An intake pipe 22 is connected to the rear side of the cylinder 18, a carburetor 23 is connected to the intake pipe 22, and the intake pipe 22 and the carburetor 23 are located between the trust member frames 2. An air cleaner 24 is connected to the carburetor 23, and the air cleaner 24 is arranged below the fuel tank 10. Exhaust pipes 2 are provided in front of the cylinders 18, respectively.
5, the exhaust pipe 25 extends below the engine 17 and extends rearward, and the muffler 26 is connected to the rear end of the exhaust pipe 25.
The muffler 26 is located on both sides above the rear wheel 16. An oil tank 27 is arranged above the crankcase 19 of the engine 17.

The left and right exhaust pipes 25 are supported by the engine 17 as shown in FIGS. 5 is a side view showing a mounting state of the exhaust device, FIG. 6 is a side view showing a support portion of the exhaust pipe, and FIG. 7 is a sectional view taken along line VII-VII of FIG.

A support plate 30 is attached to the left and right exhaust pipes 25.
The end portions 30a and 30b of the support plate 30 are welded and connected to each other, and the support cylinder 31 is welded to the center portion of the support plate 30. A rubber damper 32 is baked on the support cylinder 31, and a tightening bolt 39 is inserted into the rubber damper 32 via a collar 33. The tightening bolt 39 is screwed to the mounting bracket 21 and is tightened and fixed. Vibration is dampened. Plates 33, 34 are provided on both sides of the rubber damper 32.
Is intervening.

The mounting bracket 21 is fixed to the crankcase 17 by tightening bolts 40 and 41 at positions on both sides of the tightening bolt 39, and is securely attached to the crankcase 17 at positions on both sides of the tightening bolt 39. Held in. The upper part 21a of both sides of the mounting bracket 21 is clamped and fixed to the crankcase 17 from both left and right sides by tightening bolts 42, and the lower part 21b is fixed to the rear arm bracket 7 from both sides by tightening bolts 43.

The muffler 26 connected to the exhaust pipe 25 is constructed as shown in FIGS. 8 is a sectional view of the muffler, FIG. 9 is a sectional view taken along line IX-IX of FIG. 8, and FIG.
0 is a sectional view taken along line XX in FIG.

The outer cylinder 50 of the muffler 26 has a front end opening 50a on the front side and a rear end opening 50b on the rear side. Two partition plates 53, 54 are arranged inside the outer cylinder 50, and the partition plates 53, 54 partition a front expansion chamber 55, a middle expansion chamber 56, and a rear expansion chamber 57.
The partition plates 53 and 54 have outer peripheral portions 53a and 54a.
Is press-fitted inside the outer cylinder 50, and the partition plate 53 is formed with a rib 53b as shown in FIG. 9, and the rib 53b improves the strength.

In the first expansion chamber 55, a sound absorbing material 58 is provided in the inner cylinder 5.
The outer cylinder 5 is attached to the front side of the inner cylinder 59.
The sound absorbing material 58 is held by press-fitting the support ring 60 between the sound absorbing member 58 and zero. A pair of exhaust pipes 61 are inserted and welded between the partition plate 53 and the partition plate 54. The exhaust gas expanded in the front expansion chamber 55 is squeezed by the exhaust pipe 61 and the rear expansion chamber 57. Be led to. An exhaust pipe 62 is inserted into and welded to the partition plate 54, and the exhaust gas expanded in the rear expansion chamber 57 is throttled by the exhaust pipe 62 and guided to the middle expansion chamber 56. A support collar 63 is press-fitted and attached to the partition plate 54, and an exhaust pipe 64 is welded and attached to the support collar 63. The exhaust pipe 64 restricts the exhaust gas expanded in the middle expansion chamber 56. Emitted to the atmosphere.

The front end opening 50a of the outer cylinder 50 is provided with a step portion 50c which is bent inward, and the rear end portion 70a bent inside the connecting pipe 70 is inserted into the inside of the step portion 50c. The rear end portion 70a of the 70 and the step portion 50c of the outer cylinder 50
And are fixed by welding. Rear end 7 of connecting pipe 70
0b is attached by inserting the outer cylinder 71 of the exhaust pipe 25, and the sound absorbing material 72 is attached by an inner cylinder 73 inside the outer cylinder 71 of the exhaust pipe 25. A support ring 74 is press-fitted between the support ring 74 and the support ring 73.

A part of the outer casing 50 is covered with a decorative plate 80.
The decorative plate 80 is covered by leaving d, and is fixed to the outer cylinder 50 by spot welding in the axial direction. Front end portion 8 of the decorative plate 80
0a is located in front of the front end opening 50a of the outer cylinder 50,
The rear end portion 70a of the connecting pipe 70 and the step portion 50c of the outer cylinder 50 are brought into contact with the rear end portion 70a which is bent inward of the connecting pipe 70.
It covers the welded part so that it cannot be seen from the outside.
The decorative plate 80 is located outside the vehicle body of the outer cylinder 50, and the portion 50d not covered with the decorative plate 80 is located inside the vehicle body.

Inside the rear end opening 50b of the outer cylinder 50,
The inner cap 81 is inserted and welded, and the inner cap 81 includes a ring portion 82 and a cap portion 83. The outer side 82a of the ring part 82 is press-fitted and welded to the inner side of the rear end opening 50b of the outer cylinder 50, and the outer side 83a of the cap part 83 is press-fitted and welded to the inner side 82b of the ring part 82. On the inner side 83b of the cap portion 83,
An exhaust pipe 64 for exhausting exhaust gas to the atmosphere is supported,
In this way, the ring portion 82 of the inner cap 81 is inserted and welded to the outer cylinder 50, and the outer cap 84 is attached to the cap portion 83 of the inner cap 81 by the tightening bolts 85 and nuts 86 that form a tightening means. Installation, outer cap 8
The outer peripheral end surface 84a of No. 4 is flush with the rear end opening end surface 50e of the outer cylinder 50 to cover the inner cap 81. A cover 87 is welded to the inner peripheral portion 84b of the outer cap 84, and the exhaust pipe 64 is welded by the cover 87.
It covers the portion 64a protruding from the outer cap 84.

As described above, the inner cap 81 is inserted and welded inside the rear end opening 50b of the outer cylinder 50 of the muffler 26, and the outer cap 84 is attached to the inner cap 81 by the tightening means. The strength is improved by assembling the inner cap 81 and the outer cap 84. The outer peripheral end surface 84a of the outer cap 84 is flush with the rear end opening end surface 50e of the outer cylinder 50 to cover the inner cap 81, and the welded portion of the rear end opening portion 50b of the muffler cannot be seen from the outside. The simple structure makes the muffler 26 look good.

[0025]

As described above, the invention according to claim 1 is
The inner cap is inserted and welded inside the rear end opening of the outer cylinder of the muffler, and the outer cap is attached to this inner cap by tightening means, so the strength is improved by a simple structure that assembles the inner cap and the outer cap. Can be made.

Further, since the outer peripheral end face of the outer cap is flush with the rear end opening end face of the outer cylinder to cover the inner cap, the welded portion of the rear end opening of the muffler cannot be seen from the outside, which is simple. The structure can improve the appearance of the muffler.

[Brief description of drawings]

FIG. 1 is a side view of a motorcycle.

FIG. 2 is a plan view of the motorcycle.

FIG. 3 is a front view of the motorcycle.

FIG. 4 is a rear view of the motorcycle.

FIG. 5 is a side view showing an attached state of the exhaust device.

FIG. 6 is a side view showing a support portion of an exhaust pipe.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a sectional view of a muffler.

9 is a sectional view taken along line IX-IX in FIG.

10 is a sectional view taken along line XX of FIG.

[Explanation of symbols]

 Reference Signs List 17 engine 25 exhaust pipe 26 muffler 50 outer cylinder 50a rear end opening 50e rear end opening end face 64 exhaust pipe 81 inner cap 84 outer cap 84a outer peripheral end face

Claims (1)

[Claims] 1. A motorcycle exhaust system in which an exhaust pipe is connected to an engine mounted on a vehicle body and a muffler is connected to the exhaust pipe, wherein exhaust gas is discharged to the atmosphere inside the rear end opening of the outer cylinder of the muffler. An inner cap that supports the exhaust pipe to be discharged is inserted and welded, and an outer cap is attached to this inner cap by tightening means.The outer peripheral end face of the outer cap is flush with the rear end opening end face of the outer cylinder. An exhaust device for a motorcycle, wherein the exhaust device is configured to come into contact with and cover the inner cap.