JPH0788771B2 - Muffler for motorcycles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a muffler for a motorcycle provided on the exhaust side of an internal combustion engine of the motorcycle.

[Conventional technology]

Conventionally, a first expansion chamber, a second expansion chamber and a third expansion chamber are defined in a muffler body by a first partition plate and a second partition plate, and a pipe is provided between the first expansion chamber, the second expansion chamber and the first expansion chamber. Three
A muffler for motorcycles is known in which the expansion chambers are appropriately communicated with each other and a sound absorbing material is attached to the inner surface of each expansion chamber. In this muffler for motorcycles, a high-density sound absorbing material is attached to the inner surface of the expansion chamber on the front side (exhaust pipe side), and the muffler for the motorcycle is mounted on the inner surface of the expansion chamber on the rear side. Wear sound absorbing material of high density. Exhaust gas is expanded and compressed to reduce exhaust energy to produce a sound deadening effect, and a wide range of exhaust sound from low frequency to high frequency is absorbed by the sound absorbing material mounted in the expansion chamber and having different densities.

[Problems to be Solved by the Invention]

In conventional mufflers for motorcycles, the interior surface of the expansion chamber is not surface-treated, so the interior surface of the expansion chamber is prone to rust due to harmful components in exhaust gas. Has the disadvantage that it becomes large.

SUMMARY OF THE INVENTION It is a technical object of the present invention to prevent generation of rust on the inner surface of an expansion chamber and reduce the outer shape of a muffler body in a motorcycle muffler.

[Means for Solving the Problems]

The present invention is a muffler for a motorcycle, wherein a first partition plate and a second partition plate that partition the front and rear direction are arranged in a muffler body, and a first expansion chamber, a second expansion chamber and a third expansion chamber are provided. And forming an air vent hole in the first partition plate, fitting the first inner pipe into the first partition plate to project the front end of the first inner pipe into the first expansion chamber, and the second expansion chamber and the third expansion chamber. The surface treatment of the inner surface of the expansion chamber, the sound absorbing material is attached to the outer circumference of the inner pipe, and the sound deadening member in which the outer circumference of the sound absorbing material is covered with the outer pipe having punching holes is provided inside the second expansion chamber and the third expansion chamber. Arranged. A sound absorbing material can be attached to the inner surface of the first expansion chamber, and the adsorbent material of the sound deadening member is communicated with the second expansion chamber and the third expansion chamber through the punching hole of the outer pipe.

[Action]

In the present invention, exhaust gas is expanded and compressed by the expansion chamber and the partition plate to reduce exhaust energy and produce a sound deadening effect. Then, the sound absorbing material of the sound deadening member can absorb the exhaust sound of any frequency.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side view showing a schematic structure of a motorcycle to which an embodiment of the present invention is applied, FIG. 2 is a sectional view showing an embodiment of a muffler for a motorcycle of the present invention, and FIG. It is a principal part expanded sectional view shown.

In FIG. 1, an engine 11 is mounted in the center of a vehicle body 10 of a motorcycle. On the exhaust side of the engine 11,
One end of the exhaust pipe 12 is connected, and the exhaust pipe 12 extends rearward of the vehicle body 10 along the lower portion of the vehicle body 10. A muffler 13 is connected to the other end of the exhaust pipe 12, and the muffler 13 is connected to the vehicle body 10.
The rear drive wheel 14 is mounted so as to extend in the rearward direction of the vehicle body 10 along one side portion thereof.

As shown in FIG. 2, the muffler body 20 of the muffler 13 is
The exhaust pipe is formed at the front end of the muffler body 20 by a tapered hollow pipe that gradually expands from the front end to the rear end.
The rear end of 12 is fitted. Inside the muffler body 20, the first muffler body 20 is divided into three chambers in the front-rear direction.
The partition wall plate 21 and the second partition wall plate 22 are fixed at intervals from the front. The first partition plate 21 and the second partition plate
22, the inside of the muffler body 20 is divided into a first expansion chamber 23, a third expansion chamber 25, and a second expansion chamber 24 in order from the front.

An air vent hole 211 is formed in the first partition plate 21,
In the manufacturing process of the muffler 13, the front end of the muffler 13 is directed upward, and the rear end (lower side) of the muffler 13 is used to apply a surface treatment such as a plating liquid and an inner coating liquid to the insides of the second expansion chamber 24 and the third expansion chamber 25. When the liquid is introduced, the second expansion chamber 24 and the third expansion chamber
The air in 25 flows out into the atmosphere through the air vent hole 211. Since the inner surfaces of the second expansion chamber 24 and the third expansion chamber 25 are rustproofed by the surface treatment liquid, they are prevented from rusting by the harmful gas in the exhaust gas. Since the function of the sound absorbing material deteriorates when treated with the surface treatment liquid, the sound absorbing material is not attached to the inner surfaces of the second expansion chamber 24 and the third expansion chamber 25. In this embodiment, the inside of the first expansion chamber 23 is not subjected to the rust preventive treatment by the surface treatment liquid, so that it is possible to mount the sound absorbing material on the inner surface of the first expansion chamber 23.

A lid 213 is attached to the first expansion chamber 23 side of the air vent hole 211, and in the lid 213, the exhaust gas that flows in from the exhaust pipe 12 and collides with the first partition plate 21 passes through the air vent hole 211 to a third position. It is prevented from flowing into the expansion chamber 25. The second partition plate 22 is formed with three holes, that is, two holes 221 and 222 for mounting the pipe and a hole 223 for mounting the sound deadening member. First partition plate 2
The first inner pipe 26 is fitted into the first pipe mounting hole 212 and the second partition plate pipe mounting hole 221. The front end and the rear end of the first inner pipe 26 are the first expansion chamber 23 and the first expansion chamber 23. 2 project into the expansion chambers 24, respectively. 1st inner pipe
By 26, a passage that connects the first expansion chamber 23 and the second expansion chamber 24 is formed. Hole 22 for attaching the pipe of the second partition plate 22
A second inner pipe 27 is attached to 2, and the second inner pipe 27 allows the second expansion chamber 24 and the third expansion chamber 25 to be attached.
A passage is formed that communicates with.

A lid member 28 is detachably attached to the rear end of the muffler body 20, and the lid member 28 closes the gap between the second expansion chamber 24 and the outside air side. The lid member 28 is formed in a substantially cylindrical disk shape with a double lid, and is fitted and fixed to the rear end portion of the muffler body 20. Female threaded portions 281 are formed at several locations on the peripheral surface of the lid member 28 at regular intervals, and screw holes 2 corresponding to the female threaded portions 281 of the lid member 28 are formed on the rear end peripheral edge of the muffler body 20.
01 is formed. The cover critical material 28 is fixed by screwing a screw member 29 from the outside of the muffler body 20.

A tubular sound deadening member 30 is disposed substantially in the center of the second expansion chamber 24, and the rear end of the sound deadening member 30 is fixed to the central hole of the lid member 28. The front end of the muffling member 30 is removably fitted in the muffling member mounting hole 223 of the second partition plate 22, and the front end of the muffling member 30 projects into the third expansion chamber 25. The sound deadening member 30 forms a passage that connects the third expansion chamber 25 and the outside air side.

As shown in FIGS. 2 and 3, the sound deadening member 30 has a double pipe structure including an inner pipe 31 and an outer pipe 32. The front end 32 and the rear end 322 of the outer pipe 321 are respectively bent inward and fixed to the front end and the rear end of the inner pipe 31 by welding. A large number of punching holes 323 are formed on the peripheral surface of the outer pipe 32. The punching holes 323 are located in the second expansion chamber 24 when the sound deadening member 30 shown in FIG. It is formed on the entire circumference between 22 and the lid member 28. In the cylindrical hollow portion between the outer pipe 32 and the inner pipe 31 thus formed,
A sound absorbing material 33 such as glass wool is attached. In this way, the sound deadening member 30 covers the inner pipe 31 that serves as a passage that connects the third expansion chamber 25 and the outside air side, the sound absorbing material 33 attached to the outer peripheral portion of the inner pipe 31, and the sound absorbing material 33. The outer pipe 32 is formed with a number of punching holes 323. The sound absorbing material 33 of the sound deadening member 30 is the second expansion chamber.
Exhibits the sound deadening effect of absorbing exhaust noise within 24.

Sound absorbing material of the sound deadening member 30 of the muffler 13 configured in this way
As shown in FIG. 3, maintenance of 33 is performed by removing the muffling member 30 together with the lid member 28 from the muffler body. This removal is performed by removing the screw member 29 fixing the lid member 28 and pulling out the muffling member 30 together with the lid member 28 from the muffler body 20. Then, as for the attachment, the sound deadening member 30 is inserted into the second expansion chamber 24 of the muffler body 20, the front end thereof is fitted into the sound deadening member attachment hole 223 of the second partition plate 22, and the lid member 28 is attached to the muffler body. It is carried out by fitting the cover member 28 to the muffler body 20 by screwing it into the rear end portion of the muffler body 20. In this way, the sound deadening member 30 can be easily attached and detached.

〔The invention's effect〕

In the present invention, since the inner surfaces of the second expansion chamber and the third expansion chamber of the muffler body are surface-treated, it is possible to prevent rust from being generated on the inner surfaces of the second expansion chamber and the third expansion chamber.

Further, in the present invention, an adsorbent is attached to the outer circumference of the inner pipe, and a sound deadening member in which the outer circumference of the sound absorbing material is covered with the outer pipe having punching holes is provided inside the second expansion chamber and the third expansion chamber. . Therefore, even if the adsorbent is not attached to the inner surfaces of the second expansion chamber and the third expansion chamber, the muffling function is not deteriorated, and the outer shape (diameter) of the muffler body is smaller than that of the conventional one.

[Brief description of drawings]

FIG. 1 is a side view showing a schematic structure of a motorcycle to which an embodiment of the present invention is applied, FIG. 2 is a sectional view showing an embodiment of a muffler for a motorcycle of the present invention, and FIG. It is a principal part expanded sectional view shown. 13 ...... Muffler, 20 ... Muffler body, 21 ... First partition plate, 22 ... First partition plate, 23 ... First expansion chamber, 24 ... Second expansion chamber, 25 ... Third expansion chamber , 26 ...... First inner pipe, 27 ...... Second inner pipe, 30 ...... Sound deadening member, 31 ...... Inner pipe, 32 ...... Outer pipe, 33 ...... Sound absorbing material, 211 ...... Air vent hole, 323 ...... Punching hole, 33 ... Sound absorbing material.

Claims (1)

[Claims] 1. A first section for partitioning a front and rear direction in a muffler body.
A partition wall plate and a second partition wall plate are arranged to define a first expansion chamber, a second expansion chamber and a third expansion chamber, an air vent hole is formed in the first partition wall plate, and a first inner pipe is attached to the first inner pipe. It is fitted into the partition plate and the front end of the first inner pipe is projected into the first expansion chamber, the inner surfaces of the second expansion chamber and the third expansion chamber are surface-treated, and the sound absorbing material is attached to the outer circumference of the inner pipe to remove the sound absorbing material. The sound deadening member whose outer periphery is covered with an outer pipe having punching holes
A muffler for a motorcycle disposed inside the expansion chamber and the third expansion chamber.