JPH0610114Y2 - Scarf - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a muffler used for noise reduction of a small two-cycle engine, etc., and more specifically, it effectively suppresses the collision noise of exhaust gas on the wall surface of the muffler. It is about a muffler that can be.

[Conventional technology]

In brush cutters, backpack power spreaders, etc., exhaust gas from the exhaust port of a small two-cycle engine is introduced into the muffler's muffler chamber and expanded in the muffler chamber to reduce exhaust noise.

Such a conventional muffler (eg, Jikkou Sho 59-2481)
No. 3 and Japanese Utility Model Laid-Open No. 59-150924),
The walls of the muffling room are rigid.

Further, there is also known a muffler (silencer) for reducing exhaust noise by forming a porous layer as a sound absorbing material on the inner surface of the muffler (for example, JP-A-60-206921).

[Problems to be solved by the device]

In a muffler that utilizes the expansion of exhaust gas in the muffler chamber, the exhaust gas that flows into the muffler chamber from the exhaust port of the engine violently collides with the rigid wall of the muffler chamber. The noise is increasing.

With a muffler that aims to reduce exhaust noise with a porous layer, it is possible to suppress the collision noise due to the collision of exhaust gas with the wall surface of the muffler, but fine particles such as carbon may enter and accumulate in the porous layer. However, there is a problem that the sound absorbing effect is reduced.

The object of the present invention is to muffler that expands exhaust gas from an engine to reduce exhaust noise, can effectively suppress the collision sound of exhaust gas on the wall surface of the muffler, and It is to be able to simplify the production.

[Means for Solving the Problems]

The invention will be described using the reference numerals of the drawings corresponding to the embodiments.

The muffler (16), which is the premise of this invention, is a muffler chamber that expands by introducing exhaust gas from the exhaust port (14) of the engine (10).
(28) is provided. In this muffler (16), in the present invention, the inner surface of the muffler chamber (28) is covered with the elastic layer (30) formed by applying the liquid gasket.

[Action]

A liquid gasket is applied to the inner surface of the muffler (16), and this liquid gasket is an elastic layer having a predetermined elasticity after drying.
(30) Exhaust gas from the exhaust port (14) of the engine (10) flows into the silencer chamber (28), and the exhaust noise is reduced due to expansion in the silencer chamber (28). Further, the elastic layer (30) partitioning the silencing chamber (28) collides with the exhaust gas flowing into the silencing chamber (28) to elastically increase or decrease the thickness and reduce the collision noise.

〔Example〕

 The present invention will be described below with reference to the embodiments shown in the drawings.

The drawing is a structural drawing of the embodiment. Small two-cycle engine
10 is mounted as a power source on a small work machine such as a brush cutter and a backpack power work machine, and an exhaust port 14 that communicates the inside and the outside of the cylinder 12 is provided on the side of the cylinder 12 of the small two-cycle engine 10. Gas is exhausted from the inside to the outside of the cylinder 12 through the exhaust port 14. The muffler 16 includes a box portion 18 that opens on one end surface side and a lid portion 20 that closes the opening side of the box portion 18.
And have. The box portion 18 is fixed to the cylinder 12 by bolts 24 with the inlet 22 aligned with the exhaust port 14. Lid
The bolt 20 is detachably fixed to the box portion 18 with a bolt 26 and faces the entrance 22. The muffling chamber 28 is formed by the box portion 18 and the lid portion 20 and expands the exhaust gas flowing from the exhaust port 14.

When assembling the muffler 16 to the cylinder 12, first insert the box 18
Are fixed to the cylinder 12 with bolts 24. Next, box 18
Then, a semi-fluid liquid gasket before drying is applied to the entire inner surface of the lid portion 20, and then the lid portion 20 is fixed to the box portion 18 with bolts 26. After applying the liquid gasket, dry it,
The elastic layer 30 having a predetermined elasticity is formed, and the elastic layer 30 having a predetermined heat resistance is formed over the entire inner surface side of the muffler 16. As the liquid gasket, for example, Three Bond Company 12
07c, 1207d and 1209.

The operation of the embodiment will be described.

Prior to fixing the lid 20 to the box 18, a liquid gasket is applied to the inner surfaces of the box 18 and the lid 20, and then the lid 20 is quickly fixed to the box 18 with a bolt 26. The liquid gasket before drying has adhesiveness and retains adhesion to the inner surfaces of the box portion 18 and the lid portion 20, and is bonded to each other at the boundary between the box portion 18 and the lid portion 20 to integrally Combined, box 18 and lid 20
Seal the joint with. The liquid gasket is then dried to form an elastic layer 30 having elasticity in thickness on the inner surface side of the muffler 16. Exhaust gas from the exhaust port 14 of the small two-cycle engine 10 is introduced through the inlet 22 into the silencing chamber 28.
It flows into the inside and the sound is reduced by the expansion in the muffling chamber 28. Exhaust gas also enters the silencer chamber 28 when it enters the entrance.
It collides with the portion on the side of the lid portion 20 facing 22 and further collides with another facing portion in the muffler 16 secondarily and tertiaryly. The elastic layer 30 is formed over the entire inner surface of the muffler 16, and elastically increases or decreases the thickness due to the collision with the exhaust gas in the muffling chamber 28 to reduce the collision noise.

[Effect of device]

In this device, the exhaust gas is expanded in the muffling chamber,
In a muffler that reduces exhaust noise, the muffling chamber is partitioned by an elastic layer formed by applying liquid gas.
Therefore, collision of exhaust gas with the wall surface of the muffling chamber can be effectively suppressed by elastically increasing or decreasing the thickness of the elastic layer.

Further, since such an elastic layer is manufactured by applying a liquid gasket, it is possible to omit the work of manufacturing an elastic film according to the wall shape of the muffling chamber or fixing it to the wall of the muffling chamber. , It's very easy to make and cheap, and it's easy to apply to the existing muffler. further,
Even if the elastic layer is partially damaged, the liquid gasket can be reapplied to the damaged portion without replacing the entire elastic layer, and therefore repair and maintenance are simplified. In addition, since the liquid gasket that forms the elastic layer has a binding force to each other in a state before being dried, it is possible to improve the sealing property at the joint portion of the muffler.

[Brief description of drawings]

The drawing is a structural diagram of one embodiment of the present invention. 10 ... Small two-cycle engine (engine), 14 ...
… Exhaust port, 16 …… muffler, 28 …… silencer room, 30…
… Elastic layer.

Claims (1)

[Scope of utility model registration request] A muffler (16) having a muffler chamber (28) for expanding exhaust gas introduced from an exhaust port (14) of an engine (10).
In the muffler, the inner surface of the silencing chamber (28) is covered with an elastic layer (30) formed by applying a liquid gasket.