JPH0627788Y2 - Exhaust muffler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to improvement of an exhaust muffler of an internal combustion engine.

(Prior Art) As a conventional exhaust muffler for an internal combustion engine, JP-A-62-18
There is one disclosed in Japanese Patent No. 6008, in which, as shown in FIG. 3, a foam metal communication pipe 11 having independent bubbles is disposed in an outer cylinder 12 to form an exhaust gas flow path. Exhaust muffler, the foam metal is aluminum,
It is made of nickel-chromium alloy, stainless steel, or the like.

(Problems to be Solved by the Invention) The communication pipe 11 has a high temperature (400 to 60) due to exhaust gas.
Since it is heated to 0 ° C.), heat resistance is required, and the aluminum foam metal communication pipe 11 has high sound absorption, but has a heat resistant temperature of about 400 ° C., on the other hand, nickel chromium alloy or stainless foam metal communication pipe 11 Can be used up to about 600 ° C., but it is expensive and poor in workability. Therefore, the present invention has been made in order to solve such a problem, and provides an exhaust muffler provided with a communication pipe having excellent sound absorption and heat resistance.

(Means for Solving the Problems) In the present invention, a communication pipe is formed of cast iron, a small hole penetrating the peripheral wall of the communication pipe is provided, and a convex portion and / or
Alternatively, the discharge muffler is provided with a recess.

(Operation) Since the present invention has the above-described configuration, the exhaust gas flowing out from the cast iron communicating pipe through the small hole comes into contact with the convex portion and / or the concave portion, and the dispersion is repeated to mute the exhaust sound.
On the other hand, the exhaust sound of the exhaust gas flowing in the cast iron communication pipe is transmitted to the communication pipe, absorbed by the communication pipe material, and attenuated.

(Embodiment) FIGS. 1 and 2 show an embodiment of an exhaust muffler according to the present invention, in which the steel plate outer cylinder 1 is partitioned by partition plates 2 and 2 into an appropriate number of expansion chambers 3 and 3. A discharge pipe 4 guided from the engine is connected to the expansion chamber 3 on the side, and discharge pipes 5 and 5 are connected to the expansion chamber 3 on the other side. The expansion chambers 3, 3 are communicated with each other by the steel pipe communication pipes 6, 6 and the cast iron communication pipe 7, and the peripheral wall of the cast iron communication pipe 7 is provided with a number of small holes 8, 8 penetrating therethrough. A protrusion 9 on the outer peripheral wall surface of the communication pipe 7,
Many 9 are provided.

The exhaust sound is transmitted along with the flow of the exhaust gas, and the exhaust gas flowing from the exhaust pipe 4 sequentially passes through the expansion chambers 3, 3, the steel plate communication pipes 6, 6 and the cast iron communication pipe 7, and the exhaust pipe It is discharged to the outside from 5, 5. The exhaust gas flowing in the cast iron communication pipe 7 comes into contact with the projections 9, 9 through the small holes 8, 8 and is repeatedly dispersed to mute the exhaust sound, while the exhaust gas flowing in the cast iron communication pipe 7 is silenced. The discharge sound of is transmitted to the communication pipe 7, is absorbed by the communication pipe 7 material, and is attenuated.

Although the projections 9 and 9 are provided on the outer peripheral wall surface of the communicating pipe 7 in the above-described embodiment, the same effect as that of the above-described embodiment can be obtained even if the recessed portion or the uneven portion is provided on the outer peripheral wall surface.

(Effect of the Invention) According to the present invention, the communication pipe is made of cast iron, the small hole penetrating the peripheral wall of the communication pipe is provided, and the convex and / or concave portions are provided on the outer peripheral wall surface. The effect is obtained. The exhaust muffler of the present invention is a sound absorbing material (glass wool,
If you do not use metal wool, asbestos, porous ceramics, etc., and use a sound absorbing material together, the amount used is small, so the assembly man-hours can be reduced, workability is good, and an exhaust muffler can be manufactured easily and cheaply. .

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part of a cast iron communicating pipe, and FIG. 3 is a sectional view showing a conventional exhaust muffler. 7 ... Cast iron communicating pipe, 8 ... Small hole, 9 ... Protrusion.

Claims (1)

[Scope of utility model registration request] 1. In an exhaust muffler having a communication pipe in an outer cylinder, the communication pipe is made of cast iron, a small hole penetrating the peripheral wall of the communication pipe is provided, and a convex portion and / or a concave portion is formed on the outer peripheral wall surface. An exhaust muffler characterized by being provided with.