JPS60175719A - Muffler for internal combustion engine - Google Patents

Abstract

PURPOSE:To make it possible to simply and surely attach even an outer box made of molded sound absorbing materials to an exhaust pipe, by securing a checking plate having an inclined surface so that the inclined surface is made abut against the inner surface of the box. CONSTITUTION:The outer box 2 of a muffler 1 is composed of two halves 3 which are made of molded sound absorbing materials and which are jointed together with the use of a heat-resistant bonding agent 4. Further, each half 3 is formed such that its front part is formed in a small diameter section 5, and its rear section is formed in a large diameter section 6, both being connected together through a tapered section 7. In this arrangement, several small holes 15 for sound absorption are formed in the rear part confronting the inside of the outer box 2 fitted in a recess 9 in the small diameter section 5, and a checking plate 1 is secured to the rear front end. Further, a punching plate 10 is secured to the rear end. Further, the checking plate 1 is formed of steel plates, etc., by a press-working process into a funnel shape, having an inclined surface 16a formed at its peripheral surface and abutting against the inner surface of the tapered section 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a muffler forming a part of an exhaust system for an internal combustion engine.

Conventionally, in internal combustion engines such as gasoline engines, an outer box is connected to the rear end of the exhaust pipe, and exhaust gas is introduced into the expansion chamber formed by this outer box and expanded to release the energy held by the exhaust gas. A muffler is installed to reduce exhaust noise by eliminating it.

Since the outer case of such a silencer is generally made of a steel plate, it has a sound insulating effect, but the outer case itself does not have a sound absorbing effect, so it cannot exhibit a sufficient sound damping function. Therefore, a silencer has been proposed that has a structure in which glass wool is attached to the inner surface of the outer box to provide a sound absorbing effect. However, such a structure results in a complicated structure and an increase in weight, which also causes an increase in cost.

Therefore, it is conceivable to construct the outer case from a sound absorbing material formed into a predetermined shape, but this poses a problem in connection with the exhaust pipe. In other words, conventionally, an outer case made of steel plate is used, so the outer case and the exhaust pipe can be firmly integrated by welding, but if the outer case is made of molded sound-absorbing material, the outer case can be welded. and the exhaust pipe cannot be joined.

The present invention has been made to solve the above-mentioned problems, and even when the outer box of a silencer is made of molded sound-absorbing material, the outer box and the exhaust pipe can be reliably connected with a simple structure. It is an object of the present invention to provide a muffler for an internal combustion engine that can be used in an internal combustion engine.

In order to achieve this object, the silencer according to the present invention is such that a removal stopper plate having an inclined surface is fixed to the exhaust pipe, and the inclined surface is brought into contact with the inner surface of an outer box made of a molded sound absorbing material. The gist is:

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a silencer according to the present invention, and FIG.
3 is a sectional view taken along line AA in the figure, and FIG. 3 is a sectional view taken along line BB in FIG.

The silencer (1) is applied to, for example, a motorcycle, and the outer box (2) of the silencer (1) is a divided body divided into left and right halves along the length, as shown in Fig. 3. (3) , (
3) are bonded together via a heat-resistant adhesive (4), and each divided body (3) is made of molded sound absorbing material, with a porous layer (3a) on the inside and a porous layer (3a) on the outside. It is defined as a hard layer (tight layer) (3b).

Here, the sound absorbing material constituting the divided body (3) is molded as follows.

First, inorganic fibers such as long glass fibers and ceramic fibers or organic long fibers are cut and mixed to form a cotton-like material, which is then subjected to roller pressure and needling to form a fiber mat. It is impregnated with a binder, then placed in a mold of a predetermined shape and fired. Then, a divided body (3) is obtained in which the portion in contact with the high-temperature mold surface is hardened to become a hardened layer (3b), and the other portion is a porous layer (3a). In addition, in order to increase the thickness and hardness of the cured layer (3b), it is also possible to impregnate the surface of the fiber mat with a thermosetting resin such as phenol resin or epoxy resin as a binder before firing. .

In addition, each divided body (3) has a small diameter part (5) at the tip and a large diameter part (6) at the rear half, and the small diameter part (5) and the large diameter part (8) are continuous with a tapered part (7). The inside of the small diameter part (5) has four parts (8) into which the exhaust pipe (8) fits, and the inside of the large diameter part (6) has a punching brake in the circumferential direction (10).
The four annular parts (11) into which the outer peripheral surface of the
2) has four parts into which the tail pipe (13) fits.

On the other hand, a large number of small holes (15) for sound absorption are formed in the rear part of the exhaust pipe (8) facing inside the outer box (2).
A punching plate (16) is fixed to the front end of the rear part by welding or the like, and the punching plate (10) is fixed to the rear end of the exhaust pipe (8).

Here, the removal stop plate (16) is formed by press-forming a steel plate or the like into a funnel shape, and its peripheral surface is an inclined surface ( lea), and a large number of sound-absorbing small holes (17)... are bored therein.

The procedure for assembling the silencer (1) configured as described above is performed, for example, as follows.

First, the divided body (3) is formed, and a punching plate (16) and a punching plate (10) are welded to the exhaust pipe (8) in advance.

After that, the recesses (9), (11) of each divided body (3),
And the heat-resistant adhesive (
4) Apply. Next, the recess (8) of one of the divided bodies (3)
) into the exhaust pipe (8) and the fourth part (11) into the punching plate) (10), respectively.
Further, the other divided body (3) is joined to one divided body (3) to be integrated. Then, the outer periphery of the small diameter portion (5) of the outer box (2) is tightened with a metal band (18) to form a silencer (1).

In such a silencer (1), the exhaust pipe (8) and the outer box (2) are made of adhesive (4), a punching brake (10), a top plate (16), and metal. The band (18) connects the whole area without any wobbling, and the outer box (2) does not come off backwards.

In addition, as a function of the silencer (1) itself, the expansion chamber (S) that passes through the exhaust pipe (8) and is formed in the outer box (2)
) The exhaust gas introduced into the box (2) expands and dissipates its energy, and since the outer box (2) is made of molded sound-absorbing material, a sound-absorbing effect is produced.In particular, the outside of the molded sound-absorbing material is made of a hard layer. This will also create a sound insulation effect. Therefore, the noise reduction characteristics are greatly improved compared to conventional silencers.

As explained above, according to the present invention, the outer box of the silencer connected to the exhaust pipe is made of molded sound absorbing material,
Since a recessed top plate having an inclined surface that contacts the inner surface of the outer case is fixed to the exhaust pipe, the exhaust pipe and the outer case can be reliably connected without welding. And if the outer box is made of molded sound absorbing material,
It is possible to achieve a simpler structure, lighter weight, and lower costs, and the sound deadening effect is also improved. In addition, if the outer box is constructed by joining divided bodies made of molded sound-absorbing material,
It has many effects such as making molding and assembly operations easier.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a silencer for an internal combustion engine according to the present invention, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, and FIG.
It is a sectional view taken along the B line. In the drawings, (1) is a silencer, (2) is an outer box, (3) is a divided body, (3a) is a porous layer, (3b) is a hard layer, (4)
(8) is the exhaust pipe, and (16) is the removal stop plate. Patent applicant: Kida Giken T-gyo Co., Ltd. Agent Patent attorney: 1) Toyo Ichikan Patent attorney: Kuni Ohashi Otoma Patent attorney: Yu Koyama

Claims (1)

[Claims] In a silencer formed by connecting an outer box forming an expansion chamber to an exhaust pipe, the outer box is made of a molded sound-absorbing material,
The muffler for an internal combustion engine is further characterized in that a retaining plate having an inclined surface that contacts the inner surface of the outer box is fixed to the exhaust pipe.