JPH0347412B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a muffler for an engine exhaust system. More specifically, heat-resistant thin plates such as cylindrical outer shells made by rolling steel plates and welding the rounded ends, or split outer shells made by joining symmetrical half-shells in the same direction, are hardened with a binder and formed. This invention relates to a silencer equipped with an adsorbent.

The above-mentioned sound absorbing materials are made of glass wool, rock wool, etc., and the original shape may collapse due to loosening of the stacked layers due to exhaust gas flow, mechanical vibration, etc., or bending of wire rods, etc., resulting in durability problems. Measures were taken to suppress it from the inside.

Recently, with the improvement of molded sound absorbing materials hardened with inorganic binders, depending on the application model, the original shape can be maintained without using the above-mentioned pressing member.
However, from the viewpoint of durability, the molded product and the bell need to be stabilized so that they do not move relative to the outer shell. Therefore, conventionally, it was pasted on the inner surface of the outer shell with heat-resistant adhesive,
Alternatively, this can be handled by finishing the abutting surfaces of the molded sound absorbing material so that they are in close contact with each other.

An object of the present invention is to provide a new means for stably holding the above-mentioned sound absorbing material simply and rationally.

As a means for this, an end face pressing member of the sound absorbing material is placed at the inner rounded end of the cylindrical outer shell, or at the mating surface of the half shell in the case of a split outer shell, toward the inner center of the outer shell. A concave sound absorbing material is formed protruding to approximately the same length as the thickness, and in the case of a cylindrical outer shell, the mating end surfaces of the sound absorbing material are rolled into a cylindrical shape, and in the case of a split shell, the concave sound absorbing material is inserted into each half shell along its inner surface. The sound absorber is characterized in that a sound absorbing material is held by pressing the open end of the sound absorbing material with the above-mentioned pressing member.

Preferred embodiments will be specifically described below with reference to the drawings.

Figures 1 to 3 show the simplest cylindrical silencer.
This shows an example of carrying out the present invention, in which 1 is an outer shell made by rolling a flat steel plate into a cylindrical shape, and 4 is a thickness t.
41 is an opening between the abutting end surfaces 4a and 4b of the rounded ends of the sound absorbing material 4, and 5 is the rounded end of the outer shell 1 as shown in the second figure. This shows an end face pressing member of a sound absorbing material formed by bending the inner rounded end of the inner and outer overlapping portion 3 and protruding inward approximately toward the center, and its inward protruding length is equal to the thickness t of the sound absorbing material 4. Form approximately equal.

The above two components 1 and 4 are prepared, and the sound absorbing material 4 shown in the third figure, whose circumference is formed to a predetermined size, is placed inside the outer shell 1 which is expanded outward from the finished dimensions. The holding member 5 is inserted into the outer shell 1 so as to pass through the opening 41 between the abutted end surfaces 4a and 4b.

Next, the press molding molds 61 and 62 are attached to the outer shell 1.
When pressed against the outer surface of the outer shell 1, the overlapping portion 3 of the outer shell 1 slips and is tightened and narrowed.

Outer shell 1 up to the outer diameter dimension set there.
When narrowing down, the cylindrical sound absorbing material 4 is also pressed against the inner surface of the outer shell 1 and tightened, the opening 41 is narrowed, the end surfaces 4a and 4b are pressed against both sides of the holding member 5, and the sound absorbing material 4 is moved toward the outer shell 1. It is held almost fixedly so that it does not occur.

After welding the overlapping portion 3 in this state,
A product is obtained by removing from the molds 61 and 62.

Although 21 and 22 in FIG. 1 are cone-shaped end plates, other end plates such as an annular flat plate or a flanged annular flat plate may be attached to the openings at both ends of the cylindrical outer shell. Further, the present invention can be applied to an outer shell having one or more spiral windings, and an outer shell having an oval or polygonal cross section.

FIG. 4 and subsequent figures show an example in which the present invention is applied to a split outer shell in which half shells are joined facing each other.

Reference numerals 11 and 12 indicate half shells, and flanges 11a and 12a are formed outward at the mating surface positions thereof.
are butted together and welded (Fig. 4) or caulked (Fig. 5) to form an outer shell. Reference numerals 43 and 44 indicate sound absorbing materials housed in each half shell, which are formed into a concave shape substantially similar to the concave inner surface of the shell, as shown in FIG. 13, for example.

Conventionally, the opening end surfaces 43a, 44 of the molded sound absorbing material
A is directly abutted on the line of mating surfaces of the half shells 11 and 12, but this is insufficient in terms of stable retention against exhaust gas flow and mechanical vibration.

Therefore, the present invention has been developed by pressing the facing end surfaces 43a, 44a of both sound absorbing materials 43, 44 with end surface pressing members 51, 52 of sound absorbing materials formed toward the inside of the shell at the positions of the mating surfaces of the flanges. Accordingly, the sound absorbing material is integrally bonded to the outer shell using the same principle as in the case of the cylindrical outer shell.

FIG. 4 shows another presser member 51,
This is an example in which the outer shell is constructed by welding together the flanges 11a and 12a with 52 in between. In this case, the holding members 51 and 52 may be fixed to one of the flange surfaces in advance. The length of the holding member protruding into the shell is formed to be approximately equal to the thickness t of the sound absorbing material, as in the previous example.

In FIG. 5, one of the half shells, for example, 11 coupling flanges 11a, is folded back and extended inward to integrally form end face pressing members 51 and 52 of sound absorbing material.
Half shells 11 and 12 are caulked together 31.

Flanges 11a, 1 of half shells 11, 12
The shape and dimensions of the sound absorbing material are set so that the end surfaces 43a, 44a of the sound absorbing material are sufficiently closely pressed by the pressing members 51, 52 when the sound absorbing materials 2a are combined. Note that the sound absorbing material cannot have precise dimensions due to the nature of its structure, and the end surfaces 43a and 44a have unevenness errors. Therefore, the sound-absorbing material receiving surfaces of the holding members 5, 51, 52 are made into a waveform as shown in FIG. 9 to form the above-mentioned error-absorbing margin as necessary.

Figures 6 to 8 show how the flanges 11a and 12a of the half shells 11 and 12 are connected to each other on the surface necessary for mating and joining.
1a-1, 12a-1, and surfaces 11a-2, 12a-2 extending inward longer than those surfaces are formed alternately at appropriate widths as shown in FIG. The shells 11 and 12 are molded.

And as shown in FIG. 6, the short surface 11a-
1 (12a-1) and long surface 12a-2 (11a-
2) Flanges 11a-2 and 12a that connect the half shells facing each other and extend long inwardly.
The surface -2 is used as an end face pressing member for the sound absorbing material in the mating shell.

In FIG. 7, 7 is a surface 11a forming the above-mentioned presser member.
-2, 12a-2 is a convex portion provided toward the end face of the sound absorbing material to be pressed, and has the same effect as the wave-absorbing interference shown in the example shown in FIG. 9.

10 and 11, the upper and lower pressing members 51, 52 shown in FIG.
53 and its holding parts 51 and 52, and extrude the parts between the grooves alternately on opposite sides, and place the extruded surfaces 81 and 82 against the concave bottom surfaces of the sound absorbing materials 43 and 44 just in case. This is a modification of the presser member in which the members are integrally formed.

In many cases, separately constructed end plates are attached to the split outer shell, but as shown in FIG. 12, end plates 11b and 12b may be integrally formed with the half shells 11 and 12. In this case, the present invention is applied by forming the sound absorbing materials 43 and 44 into a box shape, and the above-mentioned end plates 11b and 12
A sound absorbing material can also be attached to the inner surface of b. The holding member shown in FIG. 11 is for the above-mentioned outer shell.

In the present invention, as described above, a pressing member facing inward is formed on the inner surface of the outer shell, and the end surface of the sound absorbing material inserted along the inner surface of the shell is pressed by the pressing member to prevent the sound absorbing material from moving. It holds the sound absorbing material firmly and has the effect of bringing the outer surface of the sound absorbing material into contact with the inner surface of the outer shell through its pressing action, which also has the effect of holding the sound absorbing material integrally with the outer shell and improving its durability. be.

[Brief explanation of drawings]

The drawings show the silencer of the present invention, in which Fig. 1 is a partially cutaway front view of the cylindrical outer shell, Fig. 2 is a cross-sectional view thereof, Fig. 3 is a front view of the cylindrical sound absorbing material, and Figs. FIG. 6 is a cross-sectional view of the split outer shell, FIG. 7 is an enlarged view of a portion of FIG. 6, FIG. 8 is an exploded perspective view of a portion of the half-split shell of FIG. Fig. 5 is a partially enlarged perspective view, Fig. 10 is a cross-sectional view of the outer shell in Fig. 12, Fig. 11 is a modification of the sound absorbing material holding member used in Fig. 10, and Fig. 12 is an integral molding up to the end plate. A perspective view of the split outer shell.
FIG. 13 is a perspective view of the concave sound absorbing material. 1 is a cylindrical outer shell, 11 and 12 are split outer shells, 4 is a sound absorbing material, 5, 51, 52, 8, 1
1a-2 and 12a-2 are sound absorbing material pressing members.

Claims (1)

[Claims] 1. A cylindrical outer shell made by rolling a steel plate and welding the rounded ends, or a split outer shell made by joining symmetrical half-shells in their orientation, hardened with a binder along the inner surface and formed. In a silencer equipped with a sound absorbing material, an end face presser of the sound absorbing material is placed at the inner rounded end of the cylindrical outer shell, or at the mating surface of the half shell for a split outer shell, toward the inner center of the outer shell. The member is formed to protrude to have approximately the same length as the thickness of the sound absorbing material, and in the case of a cylindrical outer shell, the mating end surfaces of the sound absorbing material rolled into a cylindrical shape are inserted into each half shell along the inner surface of the split shell. A silencer characterized in that the sound absorbing material is held by pressing the opening end surface of the concave sound absorbing material with the above-mentioned pressing member.