JPS6113699Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an automobile muffler, and particularly to a mounting structure for a tail tube thereof.

Generally, in an automobile muffler, the length of the tail tube plays an important role in muffling exhaust noise (especially high frequency components).

For this reason, conventionally, various efforts have been made to make the tail tube as long as possible.

For example, as shown in FIG.
There is one that projects from the front part 2A of the muffler main body 2, and then bends and extends to the rear of the muffler main body 2.

In this case, the tail tube 1 can be formed much longer without protruding from the rear of the vehicle body, and the above function can be satisfied, compared to when the tail tube 1 is made to protrude from the rear surface portion 2B of the muffler main body 2.

However, with this conventional method, even though the tail tube 1 can be formed long, the tail tube 1
bulges out around the muffler body 2, so due to the layout of the rear lower surface of the vehicle body (for example,
There was a problem that the positional relationship with the gas tank, spare tire house, tires, etc.) caused problems.

Furthermore, since the heat source is disposed over a wide area, there are problems with heat damage, and furthermore, there are problems with strength and vibration because the tail tube 1 itself swings greatly.

In order to solve the above problems,
A muffler disclosed in Publication No. 60412 has been proposed.

However, the above-mentioned muffler has a problem in that airflow noise is generated when the flow of exhaust gas is turned around.

Therefore, this idea was developed by inserting a tail tube into the muffler pipe inside the muffler body to create a double pipe structure, and by forming a group of small holes in the tail tube at the part where the exhaust flow is turned back in this double pipe structure. The purpose is to solve problems.

Hereinafter, embodiments of this invention will be described based on the drawings.

In FIG. 2, 10 is a cylindrical muffler main body, and inside this main body 10, a low frequency resonator chamber 11A, a first expansion chamber 11B, a high frequency resonator chamber 11C, and a second expansion chamber 11D are sequentially arranged in the longitudinal direction. Each is separated.

The exhaust pipe 12 leading to the engine side is the pipe 1.
3A to a first expansion chamber 11B, and this expansion chamber 11B communicates to a second expansion chamber 11D through a pipe 13B.

A muffler pipe 14, which communicates with the second expansion chamber 11D through a group of small holes 14A formed in the wall thereof, is horizontally installed inside the muffler body 10 so as to penetrate through each chamber 11A to 11D. There is.

This muffler pipe 14 is supported at both ends by a bracket 16A having a double annular projection and a bracket 16B having a single projection at the front and rear surfaces 10A and 10B of the muffler body 10.

A tail tube 17 is inserted into the muffler pipe 14, one end of which is supported by an annular projection inside the bracket 16A, and the other end of which projects from the rear surface portion 10B of the muffler body 10 over a predetermined length. There is.

This tail tube 17 has an outer diameter set small so that a predetermined gap is formed between it and the inner periphery of the muffler pipe 14, and a small diameter formed on the wall surface at its base end (upstream side of exhaust gas). It communicates with the muffler pipe 14 via the hole group 17A.

In the figure, 13C is a pipe connecting the first expansion chamber 11B and the low frequency resonator chamber 11A, and 14B is a muffler pipe 14 formed on the wall of the muffler pipe 14.
This is a group of small holes that communicate with the high frequency resonator chamber 11C.

Furthermore, a perforated tube in which small holes are formed in advance in the muffler pipe 14 and tail tube 17 having small hole groups may be used, or a small hole group 14A may be formed in the muffler pipe 14 as shown in FIG. Alternatively, the rear end of the muffler pipe 14 may be opened in the second expansion chamber 11D.

Next, the operation of this invention will be explained.

The exhaust sound transmitted by the exhaust pipe 12 is sequentially introduced into the first and second expansion chambers 11B and 11D of the muffler main body 10 through pipes 13A and 13B,
The vibration energy is attenuated in stages, and is further led from the second expansion chamber 11D through the small hole group 14A to the muffler pipe 14 and the small hole group 17A to the tail tube 17, thereby dissipating the vibration energy. Dissipated to the outside.

Generally, airflow noise is generated when the direction of the exhaust flow changes suddenly, but according to this invention, the small hole group 17A is formed at the part where the exhaust flow turns around, so the airflow noise can be effectively reduced. Reduced.

During this time, the low frequency component of the exhaust sound is in the low frequency resonator chamber 11A, and the high frequency component is in the high frequency resonator chamber 1.
At 1C, the sound is canceled by appropriately canceling out the reflected sound.

In this way, the original function of the muffler body 10 is maintained as before.

Then, connect the tail tube 17 to the muffler pipe 1
4 to form a double tube structure, it is possible to incorporate the tail tube 17 into the muffler main body 10 without shortening it.

As a result, the silencing effect of the tail tube 17 mainly on high frequency components is maintained, and the tail tube 17 etc. do not bulge out around the muffler body 10, making the muffler area compact, so that the rear lower surface of the vehicle body is This is advantageous in terms of layout space.

Further, since most of the tail tube 17 is reliably held by the front and rear surfaces 10A and 10B of the muffler body 10, there is little vibration and the tail tube 17 will not be damaged or fall off due to fatigue caused by vibration.

Furthermore, since the tail tube 17 is housed inside the muffler body 10, there is no problem of heat damage.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional automobile muffler, Figure 2
The figure is a sectional view of this invention, and FIG. 3 is a sectional view of a main part of another embodiment. 10...Muffler body, 11A to 11D...Resonator chamber and expansion chamber, 13A to 13C...Pipe, 14...Muffler pipe, 17...Tail tube.

Claims (1)

[Scope of utility model registration request] A plurality of expansion chambers are separated inside the muffler body, and these expansion chambers are successively communicated with each other through pipes.
A muffler pipe that communicates with the most downstream expansion chamber is extended to the most upstream side, and a tail tube with a smaller diameter than the muffler pipe is inserted and held inside this muffler pipe in a double tube shape, and the muffler pipe and a group of small holes are inserted at the base end of the muffler pipe. A muffler for an automobile, characterized in that the muffler communicates with the muffler through the muffler body, and has a rear end portion that protrudes a predetermined length to the outside of the muffler main body.