JPS6346689Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air intake silencing device that reduces noise generated when gas is inhaled in devices such as air compressors and internal combustion engines.

It is known that in exhaust silencing devices, etc., a silencing effect can be obtained by repeatedly expanding and contracting the exhaust gas, and the present invention utilizes this principle to direct the intake air into an annular shape divided by two conical surfaces. It is intended to reduce noise by passing through the passage, and also to function as a so-called blowback prevention plate, especially when installed at the intake port of a carburetor of an internal combustion engine.

Next, the present invention will be explained in detail based on the embodiment shown in the drawings.

In this embodiment, a portable power machine such as a chainsaw 1
This is an example of a device suitable for mounting on the carburetor 3 of the aircraft, but it is a hollow box-shaped one that is integrated with an air filter via an elbow 4 to the intake port of the carburetor 3 housed in the carburetor chamber 2 provided in the fuselage. The intake noise damping device 5 according to the present invention, which is assembled in the following manner, is installed and used. This device 5 has a substantially square box-like shape and has an inner space 23 made up of two upper and lower half-housings 6 and 12 made of synthetic resin.

A substantially circular cover plate portion 8 is provided on the upper surface of the upper half-casing 6.
A support portion 25 is provided to connect the cover plate portion 8 and its outer peripheral side, and the remaining portion of the upper surface is a filter net portion 7 that communicates the interior space 23 with the outside. Preferably, the net portion 7 is molded integrally with the upper half-casing 6.

Next, an inverted cone body 20 with the apex 18 facing the inner space 23 side by making a recess 9 in the center of the lid plate part 8
to form. Also, a hole 1 for an attachment screw for attaching the basic device 5 to the fuselage etc. is located near the cone 20.
Set 0.

Further, a substantially circular mounting seat 14 is provided on the lower surface of the lower half-casing 12 at a position corresponding to the lid plate 8, and the mounting seat 14 and its outer circumferential side are arranged similarly to the upper half-casing 6. A connecting support portion 26 is provided, and the remaining portion of the lower surface is a filter mesh portion 13 that communicates the inner space 23 with the outside. The mounting seat 14 is provided with an opening 19 that faces the apex 18 of the inverted cone 20 in the center, and allows the inner space 23 to communicate with the intake port side of the carburetor 3. A truncated inverted conical surface portion 21 is provided in series with the opening portion 19 and faces the inner space 23, and its enlarged diameter peripheral edge 25 is rounded, and the cone portion 20 on the inner surface of the lid plate portion 8 facing the A narrow annular gap 2 is formed between a rounded annular guide ridge 15 having a larger diameter than the enlarged diameter peripheral edge 25 provided at the base.
I will make it possible to do 2. In addition, the upper half housing 6
A hole 16 is similarly provided at a position corresponding to the screw hole 10. Note that the joint portion 24 of the upper and lower half casings 6 and 12 is provided with a protrusion on one side and a groove on the other side, so as to maintain airtightness. Reference numerals 11 and 17 in the figure are tool hooks for inserting a screwdriver or the like to pry open the joint portion 24 during cleaning or the like.

By combining the upper and lower half casings 6 and 12 as described above, a casing having an inner cavity 23 is formed, and the inverted conical body 20 is disposed invaginated in the space 27 defined by the conical surface part 21. As a result, a smooth, substantially annular intake passage defined by the two conical surfaces, the guide protrusion 15, and the enlarged diameter peripheral edge 25 is formed.

When the intake silencer 5 according to the present invention is connected to the intake port of the carburetor 3 via the elbow 4 as shown in FIG. The air is drawn into the inner cavity 23 with a large target volume, and then smoothly guided from the annular gap 22 by the guide ridge 15 and the enlarged diameter peripheral edge 25 of the cover plate part 8, and the air drawn from the upper surface is twice approximately
The intake air from the lower surface undergoes a 180 degree change in direction and is drawn into the carburetor 3 through the annular passage through the opening 19. Therefore, the intake air is once drawn into the inner space 23 having a relatively large volume, and then rapidly contracts and undergoes a large direction change of about 180 degrees in the narrow annular space 22, and its force is greatly reduced. Since the air is rectified in the annular passage and guided again to the opening 19, which has a relatively large volume, it can effectively muffle sound.

Furthermore, when the air-fuel mixture is blown back from the carburetor 3, even if fuel droplets are generated, they are guided by the conical surface and reliably returned to the carburetor side. There is no possibility of clogging due to contamination caused by blown-back droplets.

Incidentally, in-house tests were carried out by attaching it to an air-cooled two-stroke engine with a displacement of 60 c.c. and changing the dimensions of the annular gap 22 and the shape of the annular passage defined by two conical surfaces. With the best combination, we were able to reduce the overall noise level by 5 dB and keep the output reduction to about 3%.

[Brief explanation of the drawing]

Figure 1 is a plan view of the embodiment of the present invention, Figure 2 is a bottom view of the same, Figure 3 is a cross-sectional view taken along the - arrow in Figure 1, and Figure 4 is a sectional view of the embodiment of the present invention.
The figure is a cross-sectional view taken in the same direction, and FIG. 5 is an explanatory diagram of the state of use. 6... Upper half-casing, 8... Lid plate part, 12... Lower half-casing, 14... Mounting seat, 15... Guide ridge, 19... Opening, 20... Inverted cone, 21
...Truncated inverted conical portion, 22...Annular cavity, 25...
... Expanded diameter periphery, 27... space.

Claims (1)

[Scope of utility model registration request] A truncated inverted conical surface portion 21 is provided in series with the opening 19 of the mounting seat 14 provided on the lower surface of the casings 6, 12 having an inner space 23, and its rounded enlarged diameter peripheral edge 25 is provided.
A narrow annular gap 22 is maintained between the lid plate part 8 on the upper surface of the casing, which is provided with an inverted cone body 20 that intrudes into a space 27 defined by the conical surface part 21 on the side, and the enlarged diameter peripheral edge 25. and cover the cone 20.
A rounded annular guide ridge 15 having a diameter larger than the enlarged diameter peripheral edge 25 is provided at the base of the mounting seat 14.
and filter net portions 13 and 7 provided on the outer periphery of the lid plate portion 8.
An intake silencer that allows air to be taken in by changing direction by approximately 180 degrees.