JPH0350254Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a spark arrester provided inside a muffler of an internal combustion engine.

(Prior art) Some internal combustion engines for vehicles do not have a sufficient length for the exhaust passage, and in such cases, if no consideration is taken, sparks may fly out from the muffler tail pipe. . In order to prevent this, a spark arrester is provided inside the muffler. FIG. 1 shows an example of a spark arrester devised for this purpose, in which 1 is an exhaust pipe, 2 is a muffler, and 3 is a tail pipe. The exhaust pipe 1 is connected to an exhaust manifold (not shown) through a connecting pipe 4. A silencer pipe 6 is provided inside the muffler 2, and a silencer chamber 7 is formed on the outside thereof.

A spark arrester 8, which will be described next, is provided inside the tail pipe 3. The spark arrester 8 consists of a pipe 9 and a screen 10 connected to the pipe 9 at its rear end. screen 1
0 is obtained by rolling a stainless wire mesh 11 into a conical shape whose diameter increases from one end to the other, as shown in FIGS. 2 and 3, and joining the seams by spot welding 12. It turns out. The large diameter portion (rear end) is joined to the pipe 9 by spot welding 13. Note that the tip of the screen 10 is bent inward and then joined to close it. The spark arrester 8 has such a shape and is installed with the thin end facing the exhaust gas inflow direction, so that all of the exhaust gas flows into the spark arrester 8.
, the effect of extinguishing sparks will increase.

(Problem to be solved by the invention) The spark arrester 8 having the structure explained above is
The effect of extinguishing sparks can be improved depending on its shape and mounting condition, but the screen 10 cannot be manufactured without inserting the spot electrodes inside the elongated screen, so the spot electrodes may be deformed. In addition to requiring easy cooling, it also becomes necessary to insert electrodes from both ends, making spot welding difficult. Also, it is difficult to close the tip with spot welding, so it must be bent and brazed.
Another problem is that it is expensive.

Therefore, the present invention is a spark arrester that is robust, easy to manufacture, and has a long life by further improving the structure and changing the structure. This is what we are trying to provide.

(Means for Solving the Problems) The present invention provides a screen 10 installed inside the muffler 2 of an internal combustion engine as a means for solving the above problems.
In the spark arrester 8, the screen 10 is formed by folding a substantially trapezoidal wire mesh 11 in two in the long side direction, and forming a seam flange portion on both long sides in the long side direction and on both shortest sides in the short side direction. 14 is spot welded and expanded into a substantially conical shape based on the remaining short side of the weld, and a circular pipe 9 is welded and integrated with the rear end of the screen 10 to form a screen integrated with the pipe 9. 10 is inserted into the muffler 2 with the tip facing upstream of the exhaust gas inside the muffler 2, and is supported in the muffler 2 in a cantilever manner by the pipe 9 at the rear end.

(Function) With this configuration, first of all, the screen has a seam flange portion 14 made by folding a wire mesh in half, and the tip is also spot welded, so the tip becomes strong and prevents deformation. Never. Further, since the screen 10 has a so-called tapered shape that widens from the front end toward the rear end, it can be easily inserted into the muffler 2. Furthermore, a pipe 9 is welded and integrated with the rear end of the screen 10, so that the screen 10, which has become strong, is able to resist deformation and movement within the muffler 2 against vibrations that occur while the vehicle is running. etc. will not occur. Since the exhaust gas flows from the tapered tip side of the screen 10 that is firmly supported in this way,
The exhaust gas will surely pass through the screen 10 which is oriented obliquely to the flow of the exhaust gas, and will be most effective in extinguishing sparks.

(Example) An example of the present invention will be described below as shown in Figs. 4 and 5.
The same parts as in FIGS. 1 to 3 will be described with the same reference numerals. In addition, in the muffler 2 etc. into which the spark arrester 8 is inserted, the first
See diagram. In this invention, screen 1
0, fold the wire mesh 11 in half and fold the seam 14
The tips are spot welded 12, 15 and expanded into a cylindrical shape, forming a substantially conical shape that widens from the tip toward the rear end. When the screen 10 is expanded into a cylindrical shape, the tip is flattened and joined by spot welding 15.
A circular pipe 9 is attached to the rear end of this screen 10 by welding 13 to integrate it.
The screen 10 integrated with the pipe 9 in this way is inserted into the muffler 2 with the tip facing upstream of the exhaust gas inside the muffler 2, and supported in the muffler 2 in a cantilever manner by the pipe 9 at the rear end. There is.

FIG. 6 shows the procedure for deforming the screen 10. To explain this, the screen 10 is made up of a wire mesh 11 that has a substantially trapezoidal shape in the unfolded state. Therefore, the two long sides 11a and 1 in the longitudinal direction of this wire mesh 11 are
1b, a short side 11c in a direction that intersects the long sides 11a and 11b, and a shortest side 11d, which will be explained separately. First, as shown in FIG.
Fold in half along the longitudinal direction of the two long sides 11a and 11b, and fold the shortest side 11 as shown below.
Both sides of the d part and the seam flange part 14 are joined by spot welding 12, 15, and further expanded into a substantially conical shape with the short side 11c as a reference, as shown in FIG.
Next, the seam flange portion 14 is bent as shown below. A circular pipe 9 is attached to the rear end of the thus obtained screen 10 by welding 13 as described above.

In this way, exhaust gas flows from the front end to the rear end of the screen 10 inserted and attached to the muffler 2 (see FIG. 1). Therefore, the exhaust gas must pass through this screen 10, and sparks will be extinguished in this process.

(Effects of the Invention) Since the present invention is a spark arrester configured as described above, its shape allows it to be easily inserted into the muffler from the tail pipe portion. Since the narrow end portion faces the direction in which the exhaust gas comes, all of the exhaust gas passes through the screen, significantly increasing the effectiveness of extinguishing sparks. Since the tip is also spot welded, it is sturdy and will not be deformed due to vibrations caused by the running of the vehicle. Furthermore, the manufacturing process eliminates the need for special spot welding such as that described in connection with FIGS. 1-3 above. Since only a small welding margin is required to form the spark arrester, a screen with a large opening area can be obtained. Eliminating the need for brazing reduces costs and improves work efficiency during production. Moreover, due to its structure, it has many effects such as being able to extend the life of the spark arrester part and, by extension, the muffler as a whole.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a muffler to which the present invention is applied, Figure 2 is a front view of the screen part in Figure 1, and Figure 3 is a front view of the screen part in Figure 1.
The figure is a plan view of the screen shown in Fig. 2, Fig. 4 is a front view of the screen according to the present invention, Fig. 5 is a plan view of the screen shown in Fig. 4, and Figs. be. 2...muffler, 8...spark arrester, 9...
...Pipe, 10...Screen, 11...Wire mesh,
11a, 11b...long side, 11c...short side, 11
d... Shortest side, 12, 13, 15... Spot welding, 14... Joint flange part.

Claims (1)

[Scope of utility model registration request] In a spark arrester comprising a screen attached to the inside of a muffler of an internal combustion engine, the screen is formed by folding a substantially trapezoidal wire mesh in half in the long side direction,
The seam flanges on both long sides in the long side direction and on both shortest sides in the short side direction are spot welded, and expanded into a substantially conical shape based on the remaining short sides of the weld, and at the rear end of the screen. A circular pipe is welded and integrated, and the screen integrated with the pipe is inserted into the muffler with the tip facing upstream of the exhaust gas inside the muffler, and supported in the muffler with a cantilever at the rear end of the pipe. A spark arrester for an internal combustion engine, which is characterized by: