JPH0533691Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is mainly used in small engines, and relates to a muffler equipped with a spark arrester that captures carbon mixed with exhaust gas and discharged to the outside.

[Prior Art] In small engines such as general-purpose agricultural engines, carbon is prevented from passing through the muffler in order to prevent large carbon particles mixed in the exhaust from being discharged from the muffler. Some models are equipped with spark arresters (for example, the
61-197212).

Incidentally, the exhaust outlet pipe of the muffler has a relatively small diameter due to the need to improve the silencing effect. When a spark arrester is attached to this small-diameter exhaust outlet pipe, the carbon capture area in the spark arrester also becomes small, and therefore, the spark arrester is easily clogged. Therefore, by sandwiching the flange portion of the spark arrester between the flanges that connect the cylinder and muffler to each other, and arranging the spark arrester to face the exhaust passage of a relatively large cylinder, clogging of the spark arrester can be prevented. There is something I did.

[Problems to be Solved by the Invention] However, a gasket is required between the cylinder and the flange of the muffler, and it is necessary to assemble the three parts, the muffler, the spark arrester, and the gasket, to the flange of the cylinder at the same time. Therefore, assembly is not easy and there are many parts.

This invention was made in view of the above-mentioned conventional problems, and aims to reduce the number of parts and provide a muffler with a spark arrester that is easy to assemble.

[Means for Solving the Problems] In order to achieve the above object, the invention of each claim of this application first includes forming a flange portion of a spark arrester with a thin metal plate, and connecting this flange portion with a cylinder and a cylinder. A gasket for sealing between each flange of the muffler is constituted by the flange portion itself made of the metal plate. The flange portion is fixed to the open end of the wire mesh portion of the spark arrester.

Furthermore, the invention of claim (2) integrally forms a bent part along the bag-shaped wire mesh part on the inner periphery of the flange part of the spark arrester, and connects the flange part and the wire mesh part at the bent part. They are fixed to each other, and the bent portion is divided into a plurality of pieces in the circumferential direction.

[Operation] According to the invention of each claim of this application, the gasket that seals between the flange portion of the spark arrester and each flange of the cylinder and muffler is constituted by the flange portion itself made of a thin metal plate in the spark arrester. Because of this, there is no need for a separate gasket, and since the flange portion and the wire mesh portion are fixed, the number of parts can be reduced.

Further, according to the invention of claim (2), since the bent portion fixed to the wire mesh portion is divided into a plurality of pieces in the circumferential direction of the flange portion, the rigidity of the metal plate functioning as a gasket is unnecessary. You can prevent it from getting bigger,
Therefore, even if the flange portion made of a thin metal plate is integrally fixed to the wire mesh portion, it fits well into the flanges of the muffler and cylinder and can maintain sufficient sealing performance.

[Example] Hereinafter, an example of this invention will be described with reference to the drawings.

In Fig. 1, 1 is a cylinder, 2 is a combustion chamber,
3 is an exhaust pipe of the cylinder 1, 4 is an exhaust passage, 5 is a muffler, and 6 is a spark arrester. The muffler 5 is constructed by caulking a pair of muffler cases 5a and 5b made of sheet metal into one body, and between the two muffler cases 5a and 5b, an exhaust outlet pipe 10 connects a part of the muffler cases 5a and 5b. It is integrally formed using the Note that the muffler 5 is covered with a muffler cover (not shown).

FIG. 2 is an enlarged sectional view taken along the - line in FIG. 1. Between the flange 1f of the cylinder 1 in FIG. 1 and the flange 5f of the muffler 5, there is a flange 6f of the spark arrester 6, as shown in FIG.
A muffler 5 and a spark arrester 6 are firmly fixed to the cylinder 1 with the muffler 5 and spark arrester 6 being sandwiched. The spark arrester 6 is arranged facing the exhaust passage 4,
It is housed within the muffler 5. The exhaust passage 4 is set to have a larger passage area than the exhaust outlet pipe 10 shown in FIG. 1, and by attaching the spark arrester 6 to the cylinder 1 as described above,
Clogging of the wire mesh is reduced.

In FIG. 2, the flange portion 6f of the spark arrester 6 is formed of a thin (for example, about 0.25 mm) metal plate such as stainless steel. It constitutes a gasket that seals between the A bent portion 6c along a bag-shaped stainless steel wire mesh portion 6a is integrally formed on the inner periphery of the flange portion 6f of the spark arrester 6, and the bent portion 6c and the open end of the wire mesh portion 6a are integrally formed. 6b are fixed to each other by, for example, spot welding or brazing.

3 is a partially sectional side view showing the spark arrester 6 alone, and FIG. 4 is a sectional view taken along the line -- in FIG. As shown in FIG. 4, the bent portion 6c
are divided into, for example, six parts in the circumferential direction, and are arranged at intervals from each other in the circumferential direction. Further, on the entire inner circumference of the flange portion 6f of the spark arrester 6, as shown in FIG. ing. Note that the overlapping margin of this overlapping portion 6d is, for example, about 1 mm.
It is so small that it does not affect the sealing performance due to its compatibility with the muffler 5 and cylinder 1 described above.

In FIG. 2, reference numeral 7 denotes a tightening bolt that passes through the bolt insertion hole 6e in the flange portion 6f of the spark arrester 6 in FIG.
It is screwed into the flange 1f of. 8 is a holding plate, and a spacer 9 is welded to this holding plate 8.

In FIG. 3, the flange portion 6f of the spark arrester 6 is located near the inner circumference 6g of the flange portion 6f.
And the vicinity of the bolt insertion hole 6e is the wire mesh portion 6
It is formed by press working so as to protrude on the a side. Therefore, the flange portion 6f made of a thin metal plate has a spring property in the tightening direction A of the tightening bolt 7 in FIG. As such, it remains in a flat shape with sufficient elasticity to form a seal.

The wire mesh portion 6a has a folded portion 6a1 on the downstream side of the exhaust gas, which is partially folded inward as shown in FIGS. 3 and 5, and the tip portion shown in FIG. 6 is folded back. It has a portion 6a2, which closes the distal end side. In addition, in the wire mesh portion 6a, the overlapping portion 6a3 of wire meshes also overlaps with the wire mesh portion 6.
a and the flange portion 6f by the same means. The folded portion 6a2 shown in FIG. 6 can be omitted if the tip is sufficiently welded as shown in FIG. 8.

In the above configuration, the flange portion 6f of the spark arrester 6 shown in FIG. Therefore, there is no need for a separate gasket, which was conventionally made of asbestos or the like, and since the flange portion 6f and the wire mesh portion 6a are welded to each other, the number of parts is reduced. Therefore, ease of assembly is also improved.

Further, in this embodiment, as shown in FIG. 3, the vicinity of the bolt insertion hole 6e and the vicinity of the inner circumference 6g of the flange portion 6f are slightly protruded, so that the flange portion 6
Since f has springiness, the elasticity of the flange portion 6f is increased, and the sealing function around the bolt insertion hole 6e is also improved.

By the way, as a means for fixing the flange part 6f and the wire mesh part 6a to each other, a method of bending the inside of the flange part 6f along the wire mesh part 6a and spot welding this bent part and the wire mesh part 6a can be considered. However, if the bent portion is formed to extend over the entire circumference of the flange portion 6f and to be wide in the direction of arrow A,
The rigidity of the flange portion 6f made of a thin metal plate becomes unnecessarily large, and the function of the metal plate as a gasket deteriorates. Further, the capture area of the wire mesh portion 6a is reduced only at the bent portion.

In contrast, in this embodiment, since the bent portion 6c is divided into a plurality of pieces in the circumferential direction of the flange portion 6f in FIG. 4, it is possible to prevent the rigidity of the flange portion 6f from becoming unnecessarily large. Therefore, the flange portion 6f and the wire mesh portion 6a can be easily spot welded without reducing the function of the flange portion 6f as a gasket. Further, the bent portions 6c are provided spaced apart from each other in the circumferential direction of the flange portion 6f, and as shown in FIG.
Since carbon can also be captured by a, the capture area of the wire mesh portion 6a increases.

In addition, in this embodiment, the entire inner circumference of the flange portion 6f is curved to form a narrow overlapping portion 6d, and this overlapping portion 6d and the open end 6b of the wire mesh portion 6a are overlapped, so that the wire mesh Carbon can be prevented from being discharged from the open end of the portion 6a. In addition, the above-mentioned polymerization part 6d
Since the width of the flange portion 6f is narrow in the direction of the arrow A, there is little possibility that the rigidity of the flange portion 6f will become unnecessarily large.

By the way, in this embodiment, as shown in FIG. 6, a folded part 6a1 is formed on the exhaust downstream side of the wire mesh part 6a, and the tip of the wire mesh part 6a is closed by a folded part 6a2. The structure of the spark arrester 6 shown in FIG. 6 is simpler than the case where the tip is closed with another wire mesh 6h as shown in the other embodiment shown in FIG. Moreover, there is no fear that the capture area of the wire mesh portion 6a will decrease.

Further, as described above, the folded portion 6a1 is provided in the wire mesh portion 6a.
By providing the cylindrical wire mesh portion 6a in FIG.
The rigidity of the wire mesh portion 6a is increased, and the shape retention of the wire mesh portion 6a is improved.

Note that the wire mesh 6h in FIG. 7 may be formed of sheet metal.

Incidentally, in the above embodiment, the flange portion 6f shown in FIG. 3 has spring properties, but the flange portion 6f may be formed into a flat plate shape. In addition, the flange portion 6f
The thickness of the metal plate varies depending on the material of the metal plate, but it is usually about 0.1 mm to 0.5 mm.

[Effects of the invention] As explained above, according to the invention of each claim of this application, the flange portion of the spark arrester is formed of a thin metal plate and the flange portion itself functions as a gasket, so the number of parts is reduced. is reduced and ease of assembly is improved.

Further, according to the invention of claim (2), since the bent portion is divided into a plurality of pieces, it is possible to prevent the rigidity of the flange portion from increasing unnecessarily, and therefore, the sealing performance of the flange portion is reduced. The flange part and the wire mesh part can be easily fixed together without causing any damage.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a muffler with a spark arrester showing an embodiment of this invention, and Fig. 2 is a -
3 is a partially sectional side view of the single spark arrester, FIG. 4 is a sectional view taken along the - line in FIG. 3, FIG. 5 is a sectional view taken along the - line in FIG. FIG. 7 is a partial sectional view showing another example of the wire mesh portion, and FIG. 8 is a side view showing still another example of the wire mesh portion. 1... Cylinder, 1f... Flange, 5... Muffler, 5f... Flange, 6... Spark arrester, 6a... Wire mesh portion, 6b... Open end, 6c...
...Bent part, 6f...Flange part.

Claims (1)

[Claims for Utility Model Registration] (1) A muffler with a spark arrester, in which the spark arrester is fixed to the muffler by sandwiching the flange portion of the spark arrester between flanges that connect the cylinder and the muffler, which The flange portion of the spark arrester is formed of a thin metal plate, and constitutes a gasket that seals between this flange portion and each flange of the cylinder and muffler. A muffler with a fixed spark arrester. (2) In claim (1), the flange portion of the spark arrester is integrally formed with a bent portion along the bag-shaped wire mesh portion on the inner periphery thereof, and the flange portion and the wire mesh portion are connected at the bent portion. A muffler with a spark arrester, in which the bent portions are fixed to each other, and the bent portion is divided into a plurality of pieces in the circumferential direction.