JPS6314015Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a muffler installed in the exhaust system of a general-purpose engine, and more particularly, to a muffler with a silencer.

[Prior Art] As a muffler with a silencer of this type, a muffler body with an open facing surface and a muffler cap are combined to form a muffler chamber. In this muffler, a silencer is generally installed in the silencing chamber in order to reduce exhaust noise in the middle of the exhaust flow path from the exhaust inflow side to the outflow side. The mounting member is installed across the muffler body and muffler cap, and therefore, when the muffler body and muffler cap are joined together to assemble the muffler, the assembly process is extremely troublesome.
Also, when installing a silencer, dimensional errors,
There is often looseness due to insufficient assembly or other reasons. However, in the exhaust system of a general-purpose engine that uses this type of muffler, the muffler is connected directly to the cylinder exhaust pipe and is short, so the exhaust pulse pressure has a strong influence on the silencer without any buffering.
It makes a strong rattling noise and has a negative impact on the silencer and muffler structure.

[Purpose of the invention] The present invention was made based on the above circumstances, and it is possible to easily and reliably install the silencer when assembling the muffler, to prevent rattling, and to easily remove and clean the silencer when necessary. The purpose of the present invention is to provide a muffler with a silencer for an engine that is improved so that it can be repaired, replaced, etc.

[Example] Hereinafter, the present invention will be specifically explained based on the illustrated example. In the figure, reference numeral 1 denotes a crankcase, and a recoil star 2 equipped with a handle 20 for starting operation is provided on the front side of the crankcase. A cylinder 3 is connected to the crankcase 1 and has a piston (not shown) installed therein. The cylinder 3 has a heat radiation fin 3a on the outer periphery of the cylinder wall 3b, and constitutes a combustion chamber 3c with a plug 3d at the top, and has an exhaust port 3g opened in the inner wall of the cylinder, and an exhaust path connected to the exhaust port 3g. 3f is formed in the exhaust pipe 3e. Further, flanges 3h are formed on both sides of the exhaust pipe 3e, and screw holes 3j are formed in these flanges 3h. In addition, in the figure, the code|symbol 3k is a scavenging port. Further, a fan wheel 4 that also serves as a magnet wheel and a flywheel is provided on the back side of the crankcase 1, and a fan cover 5 is attached to surround this. A guard 5b for attachment is formed. A cylinder cover 6 is provided on the outside of the cylinder 3, and an exhaust port 6a is opened at the front of the cylinder cover 6, and a bulge 6b is provided corresponding to the plug attachment part. A notch 6c is formed near the connection portion of the exhaust pipe 3e. Further, a hook-shaped mounting fitting 6d that is engaged with the muffler cover 23 is provided. Further, a fuel tank 7 is provided at the waist of the engine, and an injection port is opened on one side of the front, and a cap 7a is removably provided here. Further, a stand 8 made of bent plate material is attached to the bottom of the crankcase 1 to support the engine.

The muffler a according to the present invention is arranged on one side of the engine cylinder 3. The muffler a is constructed by combining a conical muffler body 12 with an open facing surface and a muffler cap 13,
There are flanges 121 and 131 at the mutual connection portions, and the flanges 121 and 131 are connected to each other by tightening bolts 16 and 17 via a packing 14 between them. The muffler body 12 includes an exhaust pipe 122 connected to the exhaust pipe 3e, and an internal flow path 122.
b communicates with the exhaust pipe 3e through the exhaust inlet 12a, and a bolt insertion hole 122d is bored in a boss portion formed integrally with the exhaust pipe 122, and the muffler body 12 and the flange 3h are connected to each other. In between, the muffler a is placed along one side of the cylinder 3 via the gasket 11, and the bolt insertion hole 132b of the cylindrical boss portion 132 formed on the muffler cap 13 side is inserted.
The muffler cap 13 and the muffler cap 13 are fixed to the cylinder 3 by screwing the tightening bolt 16 through the bolt insertion hole 122d into the screw hole 3j. An end surface 132a of the cylindrical boss portion 132 is in contact with an end surface 122a of the boss portion of the muffler body 12, and the exhaust pipe 122 has an open end 122c opening into the muffler cap 13. The cylindrical boss portion 132 forms an exhaust gas passage with its peripheral wall, and the opposing muffler body 12 also includes a partition wall 123 for the exhaust gas passage therein. Above muffle body 1
2, a stop plate member 19 is attached with a sound absorbing material 18 such as glass wool laid on the inner end surface in order to configure a sound deadening chamber 15 in a space partitioned by the peripheral wall and the partition wall 123. The stop plate member 19 has claw portions 19a formed at required locations, and is elastically engaged with the inner circumferential wall and boss portion of the muffler body 12 to support the sound absorbing material 18 such as glass wool. Further, a sound damping chamber 15 is formed on the muffler cap 13 side corresponding to the sound damping chamber 15, and a sound absorbing material 20 such as glass wool is similarly spread on the inner end surface of the muffler cap 13, and this is held by a stop plate member 21. ing. In addition, the above-mentioned stop plate member 2
1 also includes a claw portion 21a that is elastically engaged with the inner wall of the boss portion 132, and supports the sound absorbing material 20.

Above muffler body 12 and muffler cap 1
Inside the silencing chamber configured by 3, a silencer 22 is disposed downstream of the exhaust flow path. The silencer 22 has a cylindrical shape in which a sound absorbing material 223 is interposed between an inner cylinder 221 having a large number of punching holes 221e and an outer cylinder 222 having a large number of punching holes 222b. 22
Tapered portions 221a and 221b, which are bent inward, are formed at both ends of the outer cylinder 222, and a tapered portion 222a is similarly formed at one end of the outer cylinder 222.

The cylindrical silencer 22 is supported within the muffler a, with one end supported by a support protrusion 125 provided on the muffler body 12 and the other end supported by a support protrusion 135 provided on the muffler cap 13. The support protrusion 125 has an outer support part 125a having a tapered surface 125b, which is a tapered part that receives the tapered part 222a of the outer cylinder 222, and an inner support part 125a, which has a tapered part that receives the tapered part 221a of the inner cylinder 221, that is, a tapered surface 125d. 125c, and has some elasticity. Further, the support protrusion 135 surrounds the exhaust outlet 13a and connects the muffler cap 13 so that the inner cylinder 221 communicates with the exhaust outlet 13a in the tail pipe 133 provided in the muffler cap 13.
3, an inner support part 135c has a tapered part that receives the taper part 221b, that is, a tapered surface 135d, and an outer support part has a sliding surface 135b into which the outer cylinder 222 is slidably fitted. 135a. Furthermore, a notch 126 is formed in the support protrusion 125 for circulating exhaust gas into the inner cylinder 221 and the sound absorbing material 223.

In addition, the muffler body 12 and the muffler cap 13 each have a screw hole 124a inside, which is slightly different from the mounting location of the silencer 22.
A boss portion 124 and a bolt insertion hole 134 having
A boss portion 124 having a diameter a is provided, to which the bolt 17 described above is screwed, and the muffler body 12
The connection between the muffler cap 13 and the muffler cap 13 is achieved together with the aforementioned bolts 16.

Note that the muffler cover 23 described above has an opening 23a for leading out the tail pipe 133 described above.
It also includes a slit 23b, a spark plug cord protection cover 23c, and the like. Also, code 2
4 is an air supply part cover that covers the carburetor and the air cleaner (not shown).

In addition, in this embodiment, especially the silencer 22
The length of the support projections 125 and 135 is set to be substantially longer than the relative spacing between the support projections 125 and 135.

Therefore, when the muffler body 12 and the muffler cap 13 are connected by the action of the bolts 16 and 17, the silencer 22 is connected to the tapered portion 22 of the inner cylinder.
1a and 221b to each tapered surface 125d, 13
5d, and the tapered portion 222a of the outer cylinder is also pressed against the tapered surface 125b. In this case, for example, in this embodiment, the support protrusion 125 elastically supports the end of the silencer 22, and the inner support part 125c and the outer support part 125b are elastically bent to absorb dimensional errors and completely eliminate looseness. to hold. Therefore, even if the exhaust gas enters the muffler chamber 15 from the exhaust pipe 3e via the exhaust pipe 122 and is discharged from the tail pipe 133 via the silencer 22, even if it receives engine pulsations, the Silencer 22 does not rattle.

[Effects of the invention] As is clear from the above explanation, the present invention connects a muffle body and a muff cap removably with their open openings facing each other, and also forms support protrusions on the inner surface of the muffle body and a muff cap. Since the silencer is elastically clamped and a tapered portion is formed on at least one of the support protrusion or the silencer, the following effects can be obtained.

(a) There is no looseness in the installation of the silencer, and no noise is generated due to engine vibration.

(b) Since the silencer can be taken out by removing the muffler cap, replacement, cleaning and repair are easy.

(c) The silencer can be easily installed during muffler assembly work.

[Brief explanation of drawings]

Figure 1 is a front view of the engine according to the present invention, Figure 2 is a front view of the engine according to the present invention;
The figure is a rear view of the same, Figure 3 is an enlarged sectional view of the main part, Figure 4
The figure is a cross-sectional view taken along line X-X in Figure 3, Figure 5 is a cross-sectional view taken along line Y-Y in Figure 4, Figure 6 is a cross-sectional view taken along line Z-Z in Figure 4, FIG. 7 is an enlarged sectional view of the main part of FIG. 3. 12... Muffler body, 13... Muffler cap, 122... Exhaust pipe, 133... Tail pipe, 125, 135... Support projection, 22... Silencer.

Claims (1)

[Scope of claim for utility model registration] A box-shaped muffler body with an open facing surface,
In the muffler with a silencer, the muffler cap is combined to form a muffling chamber, an exhaust inlet is opened in the muffler body, and an exhaust outlet is opened in the muffler cap, wherein the muffler body and the muffler cap are detachably connected. A muffler with a silencer for an engine, characterized in that support protrusions are provided on opposing inner surfaces, at least one of the support protrusions or the silencer has a tapered part, and the silencer is elastically supported between the support protrusions.