JPH05187217A - Exhaust muffler - Google Patents

Abstract

PURPOSE:To reduce cost by intercommunicating a plurality or small expansion chambers through baffle pipes the outer peripheries of which are covered with outer covers, and integrally press-molding funnel parts, arranged on the upper stream side of a porous pipe of which the baffle pipe is composed, integrally with the outer covers. CONSTITUTION:Small expansion chambers 18, 19, 20 are intercommunicated through baffle pipes 11 and 12. The baffle pipes 11 and 12 are formed such that sound absorbing materials 34 and 35 are wound around the peripheries of porous pipes 32 and 33 and the outer peripheries of the baffle pipes are covered with outer covers 36 and 37. Funnel parts 38 and 39 arranged on the upper stream side of the baffle pipes 11 and 12 are formed integrally with the outer covers 36 and 37 through press molding. This constitution requires no separate part and reduces a part manufacture cost and assembly cost.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an exhaust muffler.

[0002]

2. Description of the Related Art A general exhaust muffler used in a motorcycle or the like is constructed such that a baffle plate divides an inside of an expansion chamber provided at a rear portion of an exhaust pipe into a plurality of small expansion chambers, and baffles are provided between the small expansion chambers. A tail pipe connected to the outside is provided in the small expansion chamber on the most downstream side, which is connected by a pipe.

Exhaust gas of the engine flows from the exhaust pipe into the small expansion chamber on the most upstream side, sequentially passes through the other small expansion chambers through the baffle pipe, and is discharged to the outside from the tail pipe after being silenced.

In a general baffle pipe, a sound absorbing material such as glass wool is wound around a perforated pipe using a punching plate or the like, and the outer circumference thereof is covered with an outer cover which is fitted in the middle so as to have a sound deadening effect on exhaust gas. At the same time, a funnel portion is provided on the upstream side of the perforated pipe so as to have a rectifying effect of exhaust gas and improve exhaust efficiency.

[0005]

However, since the funnel portion is provided by expanding one end of the pipe material and welding it as a separate component by welding it to the perforated pipe or the outer cover, the number of components of the baffle pipe increases. At the same time, the manufacturing cost of the funnel portion and the time and effort required for welding are increased, which increases the manufacturing cost of the exhaust muffler.

The present invention has been made in consideration of the above problems, and eliminates the increase in the number of constituent parts of the baffle pipe due to the installation of the funnel portion, and at the same time reduces the labor for manufacturing and welding the funnel portion to reduce the cost. The purpose is to provide an exhaust muffler capable of

[0007]

In order to achieve the above object, the exhaust muffler according to the present invention divides the inside of the expansion chamber into a plurality of small expansion chambers by means of a baffle plate, and these small expansion chambers are provided with an outer hole. In an exhaust muffler in which a sound absorbing material or the like is wound around the pipe and communicated with a baffle pipe whose outer periphery is covered with an outer cover, a funnel portion provided on the upstream side of the perforated pipe is integrally press-formed on the outer cover. It has a feature.

[0008]

[Operation] By configuring the exhaust muffler in this way,
The funnel part is formed at the same time as the outer cover is pressed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a left side view of a scooter equipped with an exhaust muffler according to the present invention. The scooter 1 has a rear wheel 3 pivotally supported on a rear portion of a power unit 2 installed at a lower rear portion of a vehicle body, and an exhaust muffler 6 is connected to an exhaust port 5 of an engine 4 located at a front portion of the power unit 2, The exhaust muffler 6 extends to the right of the rear wheel 3, for example.

The exhaust muffler 6 has an exhaust pipe 7 connected to the exhaust port 5 and an expansion chamber 8 connected to the rear portion of the exhaust pipe 7 as main components, and a tail pipe 9 is located rearward from the tail of the expansion chamber 8. It is protruding.

FIG. 2 is a vertical sectional view of the expansion chamber 8, and FIG.
FIG. 3 is a sectional view taken along line III-III in FIG. A first baffle pipe 11 and a second baffle pipe 12 which will be described later.
Are arranged side by side as shown in FIG.
In FIG. 2, the drawings are arranged vertically for easy understanding.

Inside the outer wall 13 of the expansion chamber 8, a perforated plate 14 using a punching plate or the like is stretched around the outer wall 13 with a predetermined gap provided between the outer wall 13 and the perforated plate 14. A sound absorbing material 15 such as glass wool is filled. The inside of the expansion chamber 8 is divided into, for example, three small expansion chambers by the baffle plates 16 and 17, each of which is divided into the first small expansion chamber and the first small expansion chamber.
The small expansion chamber 18, the second small expansion chamber 19, and the third small expansion chamber 20 are provided.

The tail portion of the exhaust pipe 7 is connected with a megaphone pipe 22 penetrating the baffle plates 16 and 17 and opening to the first small expansion chamber 18. Further, the other end of the tail pipe 9 protruding from the expansion chamber 8 to the outside penetrates the baffle plate 17 and is open to the third small expansion chamber 20. The middle portion between the megaphone pipe 22 and the tail pipe 9 has a double pipe structure, and the inner pipes 23, 24 are provided with a large number of holes 25, 26 to connect the inner pipes 23, 24 and the outer pipes 27, 28. Sound absorbing materials 29 and 30 are filled between them.

The first small expansion chamber 18 and the second small expansion chamber 19 communicate with each other by the first baffle pipe 11, and the second small expansion chamber 19 and the third small expansion chamber 20 communicate with each other by the second baffle pipe 12, respectively. The first and second baffle pipes 11 and 12 are attached to the baffle plate 1 by welding or the like.
It is fixed to 6,17.

The first baffle pipe 11 and the second baffle pipe 12 surround the perforated pipes 32 and 33 in which a punching plate or the like is formed into a tubular shape, and sound absorbing materials 34 and 3 such as glass wool.
5 is wound and the outer circumference is covered with outer covers 36 and 37. Here, the first and second baffle pipes 11, 1
The funnel portions 38 and 39 provided on the upstream side of 2 respectively rectify the flow of the exhaust gas flowing into the first and second baffle pipes 11 and 12, and these funnel portions 38 and 39 are the outer cover 36. , 37 are integrally provided.

FIG. 4 is a perspective view showing the detailed structure of the first baffle pipe 11, showing an embodiment of the present invention. In the present embodiment, the second baffle pipe 12
Since the structure of is the same as that of the first baffle pipe 11, the description is omitted.

Outer cover 3 of the first baffle pipe 11
6 is constituted by a pair of half covers 36a and 36b that cover the perimeter of the perforated pipe 32 half by half.
The half covers 36a and 36b are formed by pressing a steel plate or the like, and have the funnel portion 38 at one end, the porous tube support portion 41 at the other end, and the sound absorbing material 34 at the middle portion.
The bulging portion 42 covering the above is press-molded, and a flange 43 for joining is integrally provided at the edge portion in the longitudinal direction. The flanges 43 are joined together by spot welding 44 or the like. Both ends of the perforated tube 32 are fixed to the base end portion 38a of the funnel portion 38 and the perforated tube support portion 41 by welding or the like. Note that the flange 43 is omitted in FIG. 2 in order to make the drawing easier to understand.

The first baffle pipe 11 (second baffle pipe 12) thus constructed has a funnel portion 38.
Since the (39) is press-molded integrally with the outer cover 36 (37), it is not necessary to independently manufacture the funnel portion 38 (39) and weld it to the outer cover 36 (37), etc., and the manufacturing cost and the assembly cost are low. Therefore, the cost will be greatly reduced.

In the exhaust muffler 6, the exhaust gas flowing from the exhaust pipe 7 into the first small expansion chamber 18 through the megaphone pipe 22 flows into the second small expansion chamber 19 through the first baffle pipe 11, and further, Since it flows through the second baffle pipe 12 into the third small expansion chamber 20,
The sound absorbing materials 15, 29, 30, 34 and 35 simultaneously expand the sound in the third small expansion chambers 18, 19 and 20, and the sound absorbing materials 15, 29, 30, 34 and 35 sufficiently discharge the sound, and the sound is released from the tail pipe 9 to the outside. In addition,
At the inlets of the first and second baffle pipes 11 and 12, the flow of exhaust gas is rectified by the funnel portions 38 and 39, and the exhaust gas smoothly flows in, so the exhaust efficiency is significantly improved.

[0021]

As described above, in the exhaust muffler according to the present invention, the inside of the expansion chamber is divided into a plurality of small expansion chambers by the baffle plate, and these small expansion chambers absorb noise around the outer pipe. In an exhaust muffler wound with a material or the like and communicated with a baffle pipe whose outer circumference is covered with an outer cover, a funnel portion provided on the upstream side of the perforated pipe is press-formed integrally with the outer cover. is there.

Therefore, since the funnel portion is formed at the same time as the outer cover is pressed, it is not necessary to separately manufacture the funnel portion from the pipe material and weld it to the outer cover or the like as in the conventional case. Manufacturing and assembly costs are significantly reduced, and exhaust mufflers are cheaper.

[Brief description of drawings]

FIG. 1 is a left side view of a scooter to which an exhaust muffler according to the present invention is attached.

FIG. 2 is a vertical sectional view of an expansion chamber.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a diagram showing an embodiment of the present invention and is a perspective view showing a detailed structure of a first baffle pipe.

[Explanation of symbols]

 6 Exhaust muffler 8 Expansion chamber 11 1st baffle pipe 12 2nd baffle pipe 16,17 Baffle plate 18 1st small expansion chamber 19 2nd small expansion chamber 20 3rd small expansion chamber 32,33 Perforated pipe 34,35 Sound absorbing material 36 , 37 Outer cover 36a, 36b Half cover 38, 39 Funnel portion 38a Funnel base end portion 41 Perforated pipe support portion 42 Swelling portion 44 Spot welding

Claims (1)

[Claims] 1. A baffle in which the inside of an expansion chamber is divided into a plurality of small expansion chambers by a baffle plate, and between these small expansion chambers, a sound absorbing material or the like is wound around an outer pipe and the outer periphery is covered by an outer cover. An exhaust muffler in which a funnel portion provided upstream of the perforated pipe is press-molded integrally with the outer cover in an exhaust muffler communicated with a pipe.