JPH06102974B2 - Exhaust silencer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust silencer for reducing exhaust discharge noise, and more particularly to an expandable chamber that can be disassembled and has a relatively large volume. A muffler improved so that it can be installed.

<Prior Art> A muffler that combines an expansion chamber and a labyrinthine passage is used in order to reduce exhaust emission noise of an internal combustion engine or the like. In these silencers, it is common to reduce the discharge noise of exhaust gas by partitioning and forming a complicated exhaust passage and expansion chamber by partitioning the inside and reflecting and reciprocating the exhaust flow. In terms of sound deadening effect, it is advantageous to make the passage more complicated and to make the expansion chamber have a larger volume at the same time.

<Problems to be Solved by the Invention> However, a complicated passage may cause carbon in exhaust gas to be easily deposited inside the silencer, which may cause a reduction in engine output. Further, a sound absorbing material is generally used inside the silencer, but if moisture or carbon in the exhaust adheres to the sound absorbing material, the sound absorbing effect is significantly reduced and at the same time, the output of the engine is reduced.

Therefore, it is desirable to be able to clean the inside of the silencer as appropriate, and there is a technique for disassembling the silencer by inserting a perforated small-diameter tube provided with a baffle into the outer cylinder. Although disclosed in Japanese Examined Patent Publication No. 52-37142, it tends to be long and is not necessarily suitable for general-purpose engines and the like.

On the other hand, the large-capacity expansion chamber increases the outer dimensions of the entire device, and may become a factor that hinders downsizing particularly when the engine is housed in an integral housing in combination with a generator, a pump, or the like.

In view of such problems of the conventional technology, a main object of the present invention is to provide an exhaust silencer capable of easily performing internal cleaning and capable of downsizing the entire structure of the device. Especially.

<Means for Solving the Problems> According to the present invention, such an object is to provide an inflow port connected to an exhaust port of an engine, an expansion chamber connected to the inflow port via an inflow path, and the expansion chamber. An exhaust silencer having a discharge passage for communicating a chamber to the atmosphere, comprising: a flat plate-shaped member in which the inflow port is opened; and the flat plate-shaped member joined to one surface side of the flat plate-shaped member. A lid member that defines the inflow passage and the discharge passage between the lid member and a protruding member in a direction orthogonal to the other surface at a position separated from the opening of the inflow port on the other surface side of the flat plate-shaped member. A case member that defines the expansion chamber, a flange portion and a through hole that are sandwiched between the inner edge of an opening formed in the projecting portion of the flat plate member and the lid member, and a through hole. A peripheral wall portion, and a space is provided between the case member and the inner surface of the case member. A separator member that is nested inside the member, and has one end that is connected to the wall of the separator member through the wall and the other end that is connected to the discharge passage and that is extended into the separator member. A pipe member and fastening means for releasably connecting the lid member side and the case member side to each other, and at least the vicinity of the opening of the inflow port of the flat plate member is connected to the engine. It is achieved by providing an exhaust silencer characterized by:

<Operation> In this way, the expansion chamber in which the inside is divided into a plurality of chambers by the separator, and the labyrinth-like passage is formed by the through hole and the pipe member can be easily disassembled, and the flat member and Since it can be configured to be separable from the lid member, not only the inside of the expansion chamber but also the inside of the inflow path and the discharge path can be easily cleaned. Further, since the flat plate member plays a role of an exhaust gas inflow path connecting the exhaust port of the engine and the expansion chamber and a role of a stay fixing the exhaust silencer to the engine, the degree of freedom of arrangement of the expansion chamber is increased. Therefore, the silencer can be disposed by effectively utilizing the dead space generated between the engine body and the housing that houses the engine.

<Embodiment> Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 show a first embodiment of a muffler according to the present invention, which is generally a muffler as a first part and a muffler as a second part. It is composed of a main body 3, and these two parts 2 and 3 can be joined to each other in the same plane.

The lid body 2 is formed by casting, for example, a light alloy, and an exhaust inflow passage 4, a cover 5 for closing the opening of the muffler body 3, and an exhaust discharge passage 6 are continuously recessed in the inner surface thereof. Cooling fins 7 are projected on the outer surface. Further, a plurality of bolt holes 8 and 8a into which bolts described later are loosely fitted are formed near the upstream end of the exhaust inflow passage 4 and around the portion of the cover 5.

The muffler body 3 is a plate 9 that forms a joint with the lid plate 2 together with a complementary portion of the exhaust gas inflow passage 4 that is provided in the lid body 2.
And a casing 10 welded to the surface of the plate 9 opposite to the joint surface with the lid plate 2, and a separator 11 housed inside the casing 10.

The casing 10 is formed by drawing a metal plate into a cup shape, and is welded to the plate 9 as described above with a flange outwardly formed in the opening.
For example, the sound absorbing material 12 formed by molding glass wool is attached.

The separator 11 is formed between the outer surface thereof and the inner surface of the sound absorbing material 12 described above in a shape substantially similar to the casing 10 with an outer dimension capable of forming an annular chamber 13 having an appropriate volume, and at the opening thereof. Has a flange 14 formed outward. Also,
A plurality of through holes 15 are provided at a position relatively close to the opening of the peripheral wall, and a pipe member is further provided in the central portion inside the separator 11.
16 is provided so as to project from the bottom wall of the separator 11 toward the opening. The pipe member 16 has its axis curved substantially at right angles in the separator 11, and its free end is formed in a semicircular cross section (Fig. 3).
The flat portion 17 is fixed to the upper surface of the flange 14 of the separator 11.

The plate 9 is formed in a shape substantially similar to the cover plate 2, and an exhaust inlet 18 is formed at one end thereof, and a receiving hole 19 for inserting the separator 11 is formed in the center of the mounting portion of the casing 10. . Around the receiving hole 19, a recess 9a corresponding to the flange 14 of the separator 11 is formed.
And the surface of the plate 9 are flush with each other at the time of assembly.
It is designed to face. Furthermore, around the plate 9,
A tap hole 21 is cut at a position aligned with the bolt hole 8 around the cover 5 portion of the cover plate 2.

When assembling the silencer 1 configured in this way,
After the separator 11 is loosely fitted in the receiving hole 19 of the plate 9 and then the cover plate 2 is joined to the surface of the plate 9 via the gasket 21, the bolt 22 is inserted from the bolt hole 8 and screwed into the tap hole 21. . At this time, the flange 14 of the separator 11 is sandwiched between the cover plate 2 and the recess 9a of the plate 9, and the casing
The separator 11 is held and fixed in the inside 10. Furthermore, due to the recess on the inner surface of the cover plate 2 and the surface of the plate 9,
The exhaust inflow passage 4 and the central chamber 23 are defined, and an exhaust discharge passage 6 as a tail pipe communicating with the open end of the pipe member 16 is formed. The exhaust inlet 18 is aligned with the exhaust port of the engine E, and the bolt hole 8a penetrating the cover plate 2 and the plate 9 near the inlet is a mounting hole for the engine E. That is, that is, the portions of the exhaust gas inflow passage 4 of both the cover plate 2 and the plate 9 can also serve as a mounting stay for the muffler body 3 with respect to the engine.

Next, the flow of exhaust gas will be described with reference to FIG.
The exhaust gas discharged from the exhaust port of the engine E flows into the central chamber 23 inside the separator 11 through the exhaust inflow passage 4. Since the opening end 17 of the pipe member 16 is fitted in the exhaust gas discharge passage 6, the exhaust gas does not flow out directly into the atmosphere. Further, in the present embodiment, the guide rib 24 is provided on the inner surface of the cover 5 so as to form a curved surface continuous with one inner surface of the exhaust inflow passage 4 (FIG. 1), and the exhaust flow is swirled. By doing so, diffuse reflection is performed inside the separator 11 to further improve the sound deadening effect (the guide rib 24 is not shown in FIG. 2). The exhaust gas expanded in the central chamber 23 flows from the through hole 15 into the annular chamber 13 between the separator 11 and the casing 10, and after repeated expansion, the pipe member 16 fixed to the bottom of the separator 11 is removed. After that, the gas is discharged from the exhaust gas discharge path 6 into the atmosphere.

FIG. 4 shows a second embodiment according to the present invention. The parts corresponding to those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted. In this embodiment, the relationship between the lid plate 2, the casing 10 and the separator 11 is almost the same as that of the first embodiment, but the pipe member 16 is made into a straight pipe and the bottom of the separator 11 is made. It is detachably fitted to the wall, and a stud bolt 31 protruding inward from the bottom wall of the casing 10 penetrates through the central portion of the wall.
The stud bolt 31 also penetrates the portion of the cover 5 of the cover plate 2, and the nut 32 is screwed to the tip of the cover plate 2 projecting to the outside, so that the cover plate 2 as the first part The muffler body 3, which is the second part, is integrated.

A partition member 33 is fixed to the upper portion of the pipe member 16. The partition member 33 has a flat surface portion 34 having a contour equal to the outer peripheral contour of the flange 14 of the separator 11 and a recess 35 having a semicircular portion corresponding to the inner surface of the separator 11 formed integrally by press working. The pipe member 16 is inserted and fixed in a hole formed in the bottom wall of the recess 35. The partition member 33 is sandwiched between the cover plate 2 and the plate 9 together with the flange 14 of the separator 11 with the outer peripheral portion of the flat surface portion 34.

A portion of the plane member 34 of the partition member 33 adjacent to the guide rib 24 is notched corresponding to the curved surface of the guide rib 24, and is bent at a substantially right angle along a fold line in a direction intersecting with the guide rib 24. The peripheral edge of the projecting piece 36 formed by this bending is in contact with the end edge of the guide rib 24 and the inner surface of the cover 5 with relatively no gap. With these, an inflow port 37 from the exhaust inflow path 4 to the central chamber 23 is formed, and a discharge chamber 38 is defined between the inner surface of the cover 5 and the separator 11.

In the case of the present embodiment, the exhaust flow is generated by the action of the guide ribs 24 and the protrusions 36 while generating a more effective swirl while the central chamber 23
Flows in. Then, it reaches the discharge chamber 38 through the through hole 15, the annular chamber 13, and the pipe member 16, and is discharged to the outside through the exhaust discharge passage 6.

The volume of the discharge chamber 38 shown in this embodiment can be arbitrarily adjusted by the depth of the recessed portion 35 of the partition member 33, and may be a simple flat plate in some cases. The member 33 can also be applied to the first embodiment. The mounting part for the engine is no different from that of the first embodiment.

FIG. 5 and FIG. 6 partially show a small generator in which the engine having the silencer 1 according to the above-mentioned embodiment is incorporated, and the engine main body 41 has its cylinder oriented in the horizontal direction and the crankshaft. Is arranged in the vertical direction, and the recoil starter 42 is fixed to the upper end of the crankshaft, and the rotor 43 of the AC generator is fixed to the lower end. A fan 43a is integrally fixed to the rotor 43 on the upper portion of the rotor 43, and the outer periphery thereof is covered with a fan shroud 43b.

The muffler 1 is arranged diagonally below the cylinder head 44 in a direction orthogonal to the cylinder axis with the axis of the muffler body 3 oriented horizontally. And these are the whole housing
The exhaust discharge port 46 is opened at the lower left of the side surface of the housing 45 as viewed from the cylinder head 44 side.

By configuring the muffler in this way, the exhaust flow line from the exhaust inflow passage connected to the exhaust port of the cylinder head to the exhaust discharge passage is provided on the same plane substantially parallel to the cylinder axis and It is possible to fit the muffler body having a large volume expansion chamber within the widthwise dimension of the engine body 41.

The cover plate 2 is not limited to the casting shown in the above embodiment, but may be a press-molded sheet metal.

<Effects of the Invention> As described above, according to the present invention, a plurality of expansion chambers and twisted and bent exhaust passages are formed, and then these can be easily disassembled and assembled, so that they can be easily cleaned as needed. It is possible to maintain the exhaust noise reduction performance at a high level and prevent the engine output from decreasing.

In addition, since the plate (flat member) plays a role of an exhaust inflow passage connecting the exhaust port of the engine and the expansion chamber and a role of a stay fixing the exhaust silencer to the engine, the expansion chamber can be freely arranged. Since the frequency is increased, the silencer can be arranged by effectively utilizing the dead space generated between the engine body and the housing that houses the engine. This makes it possible to reduce the thickness of the body of a portable device, which is particularly important when carrying it by hand, and has a great effect of improving the commercialability.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of an exhaust silencer according to the present invention with a part cut away. FIG. 2 is a sectional view taken along the line II-II in FIG. FIG. 3 is a sectional view taken along the line III-III in FIG. FIG. 4 is a perspective view showing a second embodiment with a part thereof removed. FIG. 5 is a partial plan view of a small generator including the exhaust silencer shown in FIG. FIG. 6 is a partial elevational view of the small generator shown in FIG. 1 ... Silencer, 2 ... Lid plate 3 ... Muffler main body, 4 ... Exhaust inflow passage 5 ... Cover, 6 ... Exhaust discharge passage 7 ... Cooling fins, 8, 8a ... Bolt hole 9 ... Plate, 9a ... Dent 10 ... Casing, 11 ... Separator 12 ... Sound absorbing material, 13 ... Ring chamber 14 ... Flange, 15 ... Through hole 16 ... Pipe member, 17 ... Open end 18 ... Exhaust inlet, 19 ... Receptive hole 20 ... Tap hole, 21 ... Gasket 22 ... Bolt, 23 ... Central chamber 24 ... Guide rib, 31 ... Stud bolt 32 ... Nut, 33 ... Partition member 34 ...... Flat part, 35 …… Dimple 36 …… Projector, 37 …… Inlet 38 …… Discharge chamber, 41 …… Engine body 42 …… Starter, 43 …… Rotor 43a …… Fan, 43b …… Fan shroud 44 …… Cylinder head, 45 …… Housing 46 …… Exhaust outlet

Claims (1)

[Claims] 1. An inflow port connected to an exhaust port of an engine,
An exhaust silencer having an expansion chamber connected to the inlet through an inflow passage, and a discharge passage for communicating the expansion chamber with the atmosphere, and a flat plate-shaped member having the inlet opened. A lid member joined to one surface side of the flat plate member to define the inflow path and the discharge path between the flat plate member and the inflow port on the other surface side of the flat plate member. A case member projecting in a direction orthogonal to the other surface at a position separated from the opening to define the expansion chamber; and an inner edge of the opening formed in the projecting portion of the case member of the flat plate-shaped member. And a peripheral wall portion having a flange portion sandwiched between the lid member and the through hole, and a separator member that is nested inside the case member with a gap between the flange portion and the peripheral wall portion And one end connected to the wall of the separator member through the wall and While having a pipe member having the other end connected to the discharge passage and extending in the separator member, and a fastening means for releasably coupling the lid member side and the case member side to each other, An exhaust silencer, wherein at least the vicinity of the opening of the inflow port of the flat plate-shaped member is coupled to the engine.