JPH0614011Y2 - Silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a silencer for a two-cycle engine.

[Prior Art] An example of a conventional silencer is shown in FIGS. 4 and 5.

Reference numeral 11 is a cylinder, 13 is a muffler body (second muffling chamber), and in the muffler body 13, a guide pipe (first muffling chamber) 18 joined by brazing is arranged as shown in the drawing. The pipe 18 is provided with a plurality of holes 18a. 15
Is a stud bolt embedded in the cylinder 11 for fastening the muffler 12 and the muffler gasket 16 with a nut 17.

[Problems to be solved by the device]

 The above-mentioned conventional techniques have the following problems.

(1) Install the guide pipe (first silencing chamber) into the muffler body (second
Since it is brazed or welded in the muffler room, the number of man-hours increases and the cost increases.

(2) Since the guide pipe is a strength member when the muffler body is attached to the cylinder, the guide pipe is required to have strength in addition to the sound deadening function, which also causes a price increase.

(3) Since the stud bolt is exposed to high temperature exhaust gas,
The bolt expands and contracts due to thermal expansion, and the bolt easily loosens.

[Means for Solving the Problems]

1) To prevent exhaust gas from directly hitting the lid and silencer tightening boss, form one room (first silencer) with a thin sheet metal material and provide multiple holes on the wall surface.

2) The guide box is fixed at the same time as fixing the muffler body to the cylinder by sandwiching it between the lid and the end surfaces of the bosses (muffler body fastening bosses) formed integrally with the body.

[Action]

1) Even in the case of a split type silencer, it can be handled at low cost simply by bending the sheet metal, and it is possible to reduce the air flow noise and realize a low noise silencer.

2) Because the exhaust gas from the exhaust port does not hit the boss directly,
Prevents loosening of stud bolts.

〔Example〕

Figure 1 shows the structure of the silencer. The aluminum die-cast silencer body 1 has a bottom wall 2 closed and a plurality of holes 2'on a side wall 2 ".
With the guide box 2 made of sheet metal provided with the above, a lid 3 made of sheet metal or aluminum die casting is attached, passed through a stud bolt 15 planted in the cylinder 11, and fastened with a nut 17.

As a result, the inside of the guide box 2 forms a first silencer.

As can be understood from FIG. 2 showing the I-I cross section of FIG. 1, the guide box 2 surrounds the entire silencer inlet, and the exhaust gas directly passes through the boss 1 ′ integrally formed with the main body 1. Protect it from hits. Reference numerals 4 and 16 represent gaskets.

The operation and effect of the muffler configured in this way is as follows.

(1) Exhaust gas a discharged from the exhaust port of the engine 11 enters the guide box (first silencing chamber) 2 and further guide box 2
Through a plurality of holes 2'provided in the gas flow to the muffler body 1 as a gas flow b, at which time air flow noise is reduced.

(2) The high temperature exhaust gas a discharged from the cylinder does not directly hit the boss 1'around the stud bolt 15 that fastens the silencer body 1 and the lid 3, so that the side wall 2 "of the guide box 2 is prevented. By providing the hole 2'of the side wall 2 "in the direction perpendicular to the line connecting the two bosses 1 ', 1', the gas flow b muffler body directly contacts the bosses 1 ', 1'. Instead, it flows into the silencer body 1, and the stud bolt 15
Prevents the nut 17 from loosening due to thermal expansion.

(3) By disposing the bottom wall 2 of the guide box 2 at a distance from the lid 3, it is possible to prevent exhaust gas from directly hitting the lid 3 and generating solid noise and transmitted sound.

[Effect of device]

The silencer according to the present invention includes a silencer body having an exhaust inflow portion on one side and an open other side, a boss integrally formed inside the silencer body around the exhaust inflow portion, and a silencer body. Of the silencer body, a stud that is planted around the exhaust port of the engine and that penetrates the boss and lid of the silencer body and integrally fixes them, and the boss and lid of the silencer body. A guide box that is fixedly held between and communicates with the exhaust gas inflow portion and surrounds the entire circumference of the exhaust gas inflow portion, and a plurality of holes provided in the side wall of the guide box that does not face the boss of the silencer body, It has the following effects.

(1) Welding or tightening members are not required for mounting the guide box that brings about a noise reduction effect, and the number of steps is reduced as compared with the conventional brazing.

(2) By removing the lid, disassembly and inspection can be performed easily.

(3) Since the stud bolt for mounting the silencer is not exposed to hot exhaust gas, the nut does not loosen due to thermal expansion of the stud bolt.

[Brief description of drawings]

1 is a sectional view of a silencer according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, FIG. 3 is a perspective view of a guide box 2, and FIG. Side sectional view of integrated muffler,
FIG. 5 is a sectional view taken along line VV of FIG. 1 ... Silencer body 1 '... Boss 2 ... Guide box 2' ... Hole 2 "... Side wall 3 ... Lid 11 ... Cylinder, 15 ... Stud bolt 17 ... Nut

Claims (1)

[Scope of utility model registration request] 1. A silencer body having an exhaust inflow portion on one surface and an open other side, a boss integrally formed inside the silencer body around the exhaust inflow portion, and an opening of the silencer body. Between the lid that shields the surface, the stud bolt that is planted around the exhaust port of the engine and that penetrates the boss and lid of the silencer body and integrally fixes them, and between the boss and lid of the silencer body. A guide box which is fixedly held and communicates with the exhaust gas inflow portion and surrounds the entire circumference of the exhaust gas inflow portion, and a plurality of holes provided in the side wall of the guide box that does not face the boss of the silencer body. Silencer.