JPS61258915A - Manufacture of muffler for internal-combustion engine - Google Patents

Abstract

PURPOSE:To secure such a muffler as being excellent in silent performance inexpensively, by sticking a porous inner plate to one side of a sound absorber, forming it into a mold equal to each inner surface form of half-cut outer plates, while fitting this mold in an inner surface of each half-cut outer plate, and attaching it tight in making a pair of outer plates face each other. CONSTITUTION:A wider porous inner plate 2 is stuck to one side of a mat-form sound absorber 1 laminated with heat-proof fibers and molded into a cupped form by a mold. This cuppy molding is inset in each inner surface of half-cut outer plates 3 and 3, holding a flange part 2a at the periphery of the porous inner plate 2 in between both flange parts 3a and 3a of the outer plate 3,and it is fixed tight by welding or the like. With this constitution, since the sound absorber 1 is held by the porous inner plate 2, its setting to the outer plate inner surface becomes so easy without entailing any deformation.

Description

Detailed Description of the Invention A. Purpose of the Invention [Field of Industrial Application] The present invention relates to a muffler for an internal combustion engine such as a motorcycle, in particular, a sound absorbing material such as glass wool is coated with a sound absorbing material such as a wire mesh on the inner surface of the muffler outer plate. The present invention relates to a method of manufacturing a silencer lined with a porous inner plate.

[Conventional technology]

A silencer with the above configuration is 1, for example, Utility Model No. 55-18.
It is widely used as disclosed in No. 3424, Japanese Unexamined Patent Publication No. 55-137307, and the like.

[Problem that the invention seeks to solve]

However, it is troublesome to attach the above-mentioned sound absorbing material/perforated inner plate to the outer plate, so for example, it is difficult to fix the inner and outer plates to the desired shape and then cut the mat to fit the size of the space between the inner and outer plates. A shaped sound absorber is set on the inner surface of the outer panel, a porous inner panel is covered from the inside, and its peripheral edge is welded and fixed to the outer panel. Misalignment of the plate is likely to occur, which causes unstable quality.

In addition, especially when the outer panel is split in half, the edge of the inner panel is fixed along the inner peripheral surface inward from the outer panel mating part, so the sound absorber is attached to the inner surface of the outer panel. Since it cannot be provided on the entire circumferential surface, there is only the outer panel at the joint, and there is a risk of exhaust noise leaking.

The present invention has been proposed in view of the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a silencer that can easily and inexpensively mass-produce silencers with good quality and silencing performance.

Summary: Structure of the Invention [Means for Solving Problems] That is, the present invention provides a half-shaped muffler outer plate 3 to be loaded with a mat-like sound absorber 1 laminated with heat-resistant fibers such as glass wool. A porous inner plate 2, which is wider than the sound absorber l, is attached to one side of the sound absorber l.

The porous inner plate surface is molded to be approximately the same as the inner surface of the half-split outer plate 3, and the peripheral edge of the porous inner plate 2 protruding from the edge of the sound absorber 1 is placed on the end surface of the sound absorber 1. A flange portion 2a is formed by bending along the flange portion 2a, which protrudes outward from the end surface.

Then, the above molded product is fitted to the inner surface of the half-split outer plate 3, and the bent flange portion 2a of the porous inner plate 2 is overlapped with the mating flange portion 3a formed at the opening edge of the outer plate 3, and the above-mentioned processing is performed. A pair of half-split outer panels 3 facing each other, and a flange portion 2a*2 of the porous inner panel 2 between the flange portions 3a, 3a of the half-split outer panels 3
A muffler for an internal combustion engine is manufactured by overlapping the two parts and fixing them together by welding or the like.

[For production]

The sound absorbing body 1 and the porous inner plate 2 are easily formed at the same time into a shape that follows the inner surface of the half-split outer plate 3 to be loaded.

Since the shape of the sound absorbing body 1 is maintained by the porous inner plate 2, it becomes easy to load it into the inner surface of each half-shaped outer plate.

The sound absorber L loaded on the inner surface of each half-shaped outer plate is butted,
The flange portion 2a of the porous inner plate 2 protruding from the edge of the sound absorber 1 is sandwiched and welded between seven opposing rung portions 3a of the outer plate 3, and the sound absorber l is fixed to the outer plate. 3 is loaded in a slightly compressed state due to the elasticity of the porous inner plate 2.

〔Example〕

The embodiment shown in the figure is applied to a half-pillow-shaped silencer.

That is, the flat mat-like sound absorbing body 1 is preliminarily cut into a half-split outer panel 3.
On one side of the mat-like sound absorbing body 1, a porous inner plate 2 with a relatively narrow opening and softness is provided on one side of the mat-like sound absorbing body 1. Pasting (Fig. 3), forming molds 4 and 5 as shown in Fig. 4.
It is formed into a bowl shape as shown in FIG. This is fitted onto each inner surface of the half-shaped outer panels 3, 3, and the flange portion 2a on the peripheral edge of the porous inner panel 2 is sandwiched between the flange portions 3a, 3a of the outer panel 3, and fixed by welding or the like. Figure 2).

In the figure, 6 is an exhaust pipe, and 7 is an exhaust pipe.

C. Effects of the Invention The hole inner plate 2 and the outer plate 3 can be easily molded at the same time to match the inner surface shape of the outer plate 3 to be loaded, and since the sound absorber 1 is held in shape by the porous inner plate 2, it does not lose its shape. It is easy to load onto the inner surface of the outer panel. Also, the flange portion 2 of the porous inner plate 2
Since the sound absorber 1 is sandwiched and fixed between the facing flange portions 3a of the half-split outer plate 3, the sound absorber 1 can be assembled easily and reliably. Moreover, the sound absorber l is loaded onto the entire inner circumferential surface of the outer plate 3, and is maintained in a slightly compressed state averaged over the whole by the elasticity of the porous inner plate 2, so that variations in the density of the sound absorber occur as in the conventional case. You can easily create a silencer with good sound deadening performance that does not cause any noise or misalignment.
It has the effect of being mass-produced at low cost.

[Brief Description of the Drawings] Fig. 1 is a perspective view of a half-split pillow-shaped silencer to which the present invention is applied, Fig. 2 is a sectional view thereof, and Fig. 3 is a state in which a porous inner plate is attached to a sound absorber. FIG. 4 is a cross-sectional view of the molded state, and FIG. 5 is an oblique view of the molded sound absorber and JA snore. 1 is a sound absorber, 2 is a porous inner plate, 2a is a flange thereof, 3
is the outer plate, and 3a is its flange.

Claims (1)

[Claims] (1) A mat-like sound absorber made by laminating heat-resistant fibers such as glass wool is formed to have approximately the same size as the inner peripheral surface of the half-shaped muffler outer plate to be loaded, and one side of the sound absorber is A porous inner plate that is wider than that is attached, and the porous inner plate surface is molded to be approximately equal to the inner surface shape of the half-split outer plate, and the peripheral edge of the porous inner plate that protrudes from the edge of the sound absorber is The sound absorbing body is bent along the end face to form a flange that protrudes outward from the end face, and the above molded product is fitted to the inner surface of the half-split outer panel to extend the bent flange of the sound absorbing body. The flange portions of the perforated inner plate are overlapped with the mating flange portions formed on the edges of the openings of the plates, the pair of half-shaped outer plates processed as described above are placed facing each other, and the flange portions of the perforated inner plate are overlapped between the flange portions of the half-shaped outer plates. A method of manufacturing a silencer for an internal combustion engine that is fixed together by welding, etc.