JPH0430331Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The invention consists of a main body case having an opening that communicates with the exhaust port of the engine, and an exhaust port that engages with the main body case and communicates with the atmosphere. This relates to a muffler in which a spark prevention net for preventing sparks is provided inside a muffler case consisting of a lid case and a muffler case.

(b) Prior Art and Problems to be Solved Conventionally, in this type of muffler, for example, as shown in Fig. 4, the interior is partitioned along the engagement surface between the main body case and the lid case to allow communication. There was one in which a partition plate with pores was provided perpendicular to the direction of the exhaust port, and a spark prevention net overlaid on the partition plate was sandwiched together with the partition plate between the lid case and the main body case. This system has the drawback that the exhaust gas flows in a simple direction within the muffler case, so there is little interference of sound on the wall surface, and the sound damping effect is low. In addition, as shown in Figure 5, there is a system in which a partition plate is installed parallel to the exhaust port to partition the inside of the muffler case, and is sandwiched between the main case and the lid case, and the spark prevention net is overlapped with this partition plate. Therefore, the exhaust port was formed separately, and a spark prevention net was sandwiched between the exhaust port and the exhaust port. Therefore, the area of the spark prevention net cannot be increased, which increases the resistance of the exhaust gas, and the flow of the exhaust gas is still simple, so the noise reduction effect is low. In addition, in the past, the exhaust gas was expanded in the main body case and then passed through a spark prevention net, so the temperature dropped during expansion and the unburned lubricating oil in the exhaust gas was sufficiently re-burned. I couldn't do it.

(c) Means and action for solving the problem The present invention is characterized in that both ends of a cylindrical body with a long cross section are sandwiched between the main case and the lid case, surrounding the opening communicating with the exhaust port of the engine. At the same time, the first pipe is connected to the exhaust port through the inside of the muffler case and the cylindrical body.
It is divided into an expansion chamber and a second expansion chamber on the opposite side,
A ventilation hole is provided on the second expansion chamber side of the cylindrical body, a communication path is provided between the side end of the cylindrical body and the inner wall of the muffler case, and a cylindrical spark prevention net is engaged with the outer periphery of the cylindrical body. Since the exhaust passage can be provided in a detour, the length of the inner wall that comes into contact with the exhaust gas becomes longer, increasing the silencing effect, and the area of the spark prevention net increases, reducing exhaust resistance. can be reduced. Moreover, by providing a spark prevention net before the temperature drops in the expansion chamber, unburned lubricating oil can be completely reburned.

(d) Embodiment Hereinafter, one embodiment of the present invention will be explained in detail with reference to the drawings.

In Figures 1 to 3, the engine exhaust port 1
A muffler case 11 consisting of a main body case 5 having an opening 3 communicating with the main body case 5 and a lid case 9 having an exhaust port 7 engaging with the main body case 5 and communicating with the atmosphere is secured by bolts 13, 13. and is fixed to the exhaust port 1. Inside the muffler case 11,
A cylindrical body 15 having a long cross section is held between the main case 5 and the lid case 9, surrounding the opening 3. The interior of the muffler case 11 is divided by the cylinder 15 into a first expansion chamber 16 communicating with the discharge port 7 and a second expansion chamber 18 on the opposite side.
A ventilation hole 17 is provided on the 8 side, and a communication passage 20 is provided between the side end of the cylinder and the inner wall of the muffler case 11.
A cylindrical spark prevention net 19 is engaged with the outer periphery of the cylindrical body 15. One end of a muffler gutter 21 communicates with the inner surface of the discharge port 7, and the other end of the muffler gutter 21 opens into the muffler case 11. Further, a reinforcing plate 23 is welded to the outer surface of the opening 3.

In the above embodiment, the exhaust gas from the engine enters the cylinder 15 through the exhaust port 1, and the ventilation holes 17, 17.
It enters the second expansion chamber 18 through the communication passage 20 at the side end of the cylinder body 15, flows into the first expansion chamber 16 on the opposite side, passes through the muffling gutter 21, and is discharged to the atmosphere from the discharge port 7. During this time, the exhaust gas is throttled and expanded to buffer the exhaust pressure, and a detour is performed to increase the distance of contact with the inner wall, which causes sound interference and increases the silencing effect. Further, the sparks that ignite the carbon generated in the exhaust passage are removed by the spark prevention net 19 and prevented from being released into the atmosphere, but since the spark prevention net 19 can be formed with a large area, the exhaust resistance is reduced. It doesn't get bigger.

In addition, since the spark prevention net 19 is provided at a position immediately before the high-temperature, high-pressure exhaust gas expands in the expansion chamber 16, the spark prevention net 19 is heated by the high-temperature exhaust gas before its temperature drops, and is added to the exhaust gas. The unburned lubricating oil contained therein can be reburned to prevent environmental pollution caused by exhaust gas. In addition, the cylindrical body 15
This effect can be further improved by filling the inside with metal fibers.

(e) Effect of the invention Since the present invention has the configuration as described in the claims, it has a large noise reduction effect, can prevent the release of sparks without increasing exhaust resistance, and can reduce exhaust gas. It is possible to completely re-burn the unburned lubricating oil inside.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented in other embodiments as well. Further, the symbols shown in the claims do not limit the technical scope of the present invention.

Note that FIG. 4 shows a first conventional example, in which a partition plate 27 that partitions the inside and is provided with a ventilation hole 25 is placed on the engagement surface between the main body case 5 and the lid case 9 in the direction of the exhaust port 1. A spark prevention net 29 is provided perpendicularly to the partition plate 27 and is sandwiched between the lid case 9 and the main body case 5. In addition, FIG. 5 shows that the interior of the muffler case 11 is partitioned and
0 is sandwiched between the main body case 5 and the lid case 9 in parallel with the direction of the exhaust port 1.
A spark prevention net 35 is held between the main body case 5 and the main body case 5 by screws (not shown).

[Brief explanation of the drawing]

Figure 1 is a side sectional view of one embodiment of the present invention;
Figure 3 is the - line in Figure 1, respectively.
A front sectional view taken along the - line, FIGS. 4 and 5 are side sectional views of the first and second conventional examples, respectively. 1... Exhaust port, 3... Opening, 5... Main body case, 7... Discharge port, 9... Lid case, 11... Muffler case, 15... Cylindrical body, 16... First expansion chamber, 17...Vent hole, 18...Second expansion chamber, 19
...Spark prevention net, 20...Communication path.

Claims (1)

[Scope of utility model registration request] A main body case 5 having an opening 3 that communicates with the exhaust port 1 of the engine, and a lid case 9 having an exhaust port 7 that engages with the main body case 5 and communicates with the atmosphere.
Inside the muffler case 11, which is made up of is divided by the cylinder body 15 into a first expansion chamber 16 communicating with the discharge port 7 and a second expansion chamber 18 on the opposite side, and is connected to the second expansion chamber 18 side of the cylinder body 15. In addition to providing air holes 17, a communication passage 20 is provided between the side end of the cylinder 15 and the inner wall of the muffler case 11, and a cylindrical spark prevention net 19 is engaged with the outer periphery of the cylinder 15. A muffler characterized by: