JPH03189315A - Silencer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a muffler used as a pre-muffler or main muffler of an exhaust system.

(Prior Art) As a muffler, there is a so-called press muffler in which a main body 1 is made by press-molding an outer plate, as shown in FIG.

This type of silencer has a particularly large main body outer panel part la,
lb tends to generate vibrations due to exhaust pulsation, which often becomes a sound source and generates radiated sound.

Therefore, in the past, beads were formed on the outer panel for reinforcement, or reinforcing members were attached to the inner surface of the outer panel as described in Japanese Utility Model Application Publication No. 63-63520.

(Problems to be Solved by the Invention) However, in order to prevent radiated sound, deep beads and large reinforcing members are required, and the internal volume of the muffler body is significantly reduced, thereby losing the advantage of the press muffler.

The present invention aims to solve the above-mentioned problem by compensating for the decrease in the silencing function due to the decrease in the internal volume of the main body by using the reinforcing member for silencing, although it depends on the measure of attaching the reinforcing member. .

(Means for Solving the Problems) For this purpose, the present invention provides a silencer having a main body whose outer panel is press-molded, in which both side walls of a groove-shaped reinforcing member are fixed to the inner surface of the outer panel, and the outer panel is press-molded. A number of through holes are bored in the bottom wall between both side walls of the groove-shaped reinforcing member, and a sound absorbing material is placed thereon.

(for production) The exhaust air is expanded and muffled as it enters the body.

At this time, even if the outer plate of the main body attempts to vibrate due to the pulsation of the exhaust, it will not vibrate and no radiated sound will occur because the outer plate is reinforced by the addition of reinforcing materials. Furthermore, when the remaining sound waves reach the sound absorbing material through the through holes drilled in the bottom wall of the reinforcing member, the acoustic energy is attenuated by friction with the sound absorbing material.

By the way, it would be a problem if the reinforcing member provided to counter radiated sound reduces the internal volume of the main body, but as mentioned above, this reinforcing member is used together with the sound absorbing material for sound deadening, so there is no reduction in the sound deadening effect, and the exhaust gas This makes it possible to achieve reliable sound reduction.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 3 show embodiments of the present invention, in which the same parts as in FIG. 4 are designated by the same reference numerals.

FIG. 1 shows the silencer of this example as a cross section at a portion corresponding to the line 1-■ in FIG. It is also arranged and attached in the axial direction of the exhaust pipe 3. For this attachment, as clearly shown in FIG. 2, both side walls 2a, 2b of the groove-shaped reinforcing member 2 are welded (indicated by 4) to the inner surface of the outer plate portion 1a of the main body.

A partition wall 5 made of a channel member is bridged between both side walls 2a and 2b of the groove-shaped reinforcing member 2, and is fixed to the reinforcing portion 2 by spot welding 6 as shown in FIG. Divide into two in the depth direction. A large number of through holes 2d are bored in the bottom wall 2c between the side walls 2a and 2b of the reinforcing member 2, and through holes 5a are also formed in the partition wall 5. The space 7 between the partition wall 5 and the outer plate portion 18 is left empty, and the space between the partition wall 5 and the reinforcing member bottom wall 2c is filled with sound absorbing material 8.

The operation of the above embodiment will be explained next.

Exhaust gas flowing into the main body 1 from the pipe 3 is expanded within the main body 1 and is muffled in a predetermined manner. At this time, the outer panel of the main body 1 is subjected to the pulsation of the exhaust gas, but since the outer panel of the main body is strengthened by the reinforcing member 2 attached to the outer panel portion 1a, no vibration is generated and the generation of radiated sound is prevented. be done.

On the other hand, the sound waves that have not been completely muffled and remain inside the main body 1 are
d, it reaches the sound absorbing material 8, and the acoustic energy is absorbed by friction with this material. Then, the sound absorbing material 8 is directly applied to the outer panel part 1.
a, and there is an air layer in the space 7 between them, so this air layer blocks high-frequency sounds, and this air layer also produces a resonance effect and attenuates medium-frequency sounds. let

In this way, the reinforcing member 2 provided for countermeasures against radiated sound achieves a sound-deadening effect with the sound-absorbing material 8 and the air layer in the space 7, and when the reinforcing member 2 reduces the internal volume of the main body l, the neck also decreases. This can sufficiently compensate for the reduction in the silencing effect.

(Effects of the Invention) Thus, as described above, in the silencer of the present invention, the reinforcing member attached to the inner surface of the outer panel of the main body is shaped like a groove to prevent radiated noise, and both side walls of the reinforcing member are fixed to the outer panel of the main body. Since the structure has many through holes in the bottom wall between the walls and a sound-absorbing material is placed, the reinforcing member also has a sound-dampening function, which reduces the internal volume of the main body and reduces the sound-dampening effect. However, the overall sound deadening effect can be maintained so as not to be insufficient.

Furthermore, if a space is provided between the sound-absorbing material and the outer panel to form an air layer as in claim 2, this will not only block high-frequency sounds from the sound-absorbing material, but also attenuate medium-frequency sounds due to the resonance effect. As a result, the sound deadening effect of the - layer can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagrammatic sectional view showing an embodiment of the silencer of the present invention as a cross section at a location corresponding to line I-1 in FIG. 4; FIG. FIG. 3 is a perspective view of the reinforcing member on the same side, and FIG. 4 is a perspective view illustrating the overall shape of the breath muffler. 1... Main body 2... Channel-shaped reinforcing member 2a
, 2b... Same side wall 2c... Same bottom wall 2d.
...Through hole 3...Exhaust pipe 5...Partition wall 7...Vacancy 5a...Through hole 8...Sound absorbing material

Claims (1)

[Scope of Claims] 1. In a silencer equipped with a main body whose outer plate is press-molded, both side walls of a groove-shaped reinforcing member are fixed to the inner surface of the outer plate, and a gap between the both side walls of the groove-shaped reinforcing member is fixed to the inner surface of the outer plate. A silencer characterized by having a number of through holes in the bottom wall and placing a sound absorbing material on the bottom wall. 2. The muffler according to claim 1, characterized in that a space is provided between the sound absorbing material and the outer panel.