JP3170979B2 - Silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for suppressing noise generated or transmitted to a flue gas pipe.

[0002]

2. Description of the Related Art A muffler 51 provided in an intake pipe of a conventional automobile internal combustion engine.
As shown in FIG. 5, a resonance silencer 53 (resonator) is provided outside the intake pipe 52 at a distance, and the intake pipe 52 and the resonance silencer 53 are communicated by a communication pipe 54.
2, the side branch 55 is protruded outside.

However, in the above-described muffler 51, since the resonance muffler 53 and the side branch 55 are separated from or protrude from the intake pipe 52 and are bulky, a space for disposing the muffler 51 in the engine room is secured. There was a problem that it was difficult. Further, since each part is formed separately and then assembled with the fastening ring 56 or the like, the number of steps and the number of parts are large, and the cost is high.

Therefore, as shown in FIG. 6, an intake pipe 62 provided with one through hole 63 in the pipe wall,
And a blow molded body 64 having a resonance silence chamber 65 communicating with the intake pipe 62 by using the through hole 63 as a communication hole. (Japanese Unexamined Patent Publication No. 1-255355
No. 9). Since the suction pipe 62 and the blow molded body 64 are adjacent to each other, the silencer 61 can be formed compact. Further, since the blow molded body 64 is joined to the intake pipe 62 at the same time as the blow molding, the man-hour and the number of parts are small, and the cost can be reduced.

[0005] However, the sound deadening frequency band due to the resonance action of the above sound deadening device 61 depends on the volume of the sound deadening chamber 65 and the through hole 6.
Since only one (excluding overtones) is determined by the area and the length of No. 3, a sufficient reduction effect may not be obtained when the frequency range of the noise is wide.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to obtain a plurality of noise reduction frequency bands, to obtain a sufficient reduction effect even when the noise frequency range is wide, and to form the device compactly. An object of the present invention is to provide a novel noise reduction device that can reduce man-hours and the number of parts and reduce costs.

[0007]

In order to achieve the above object, according to the present invention, there is provided a muffler comprising: a flow pipe having a plurality of first and second through-tubes projecting from a pipe wall; A first resonance silencer that is blow-molded on the outer periphery of the flow tube as an insert part and surrounds the first through tube as a communication tube to the flow tube, and encloses the second through tube closely. The first molded body provided with the encapsulating part to be formed, and the first molded body is molded separately, and is joined to the first molded body, and the second penetrating cylinder and the end face are perforated. A second molded body having a second resonance silencing chamber that surrounds the envelope as a communication pipe to the air duct.

[0008] Here, the "flow pipe" is not particularly limited as long as it is a pipe through which gas flows, and examples thereof include an intake pipe and an exhaust pipe of an internal combustion engine. The length, cross-sectional shape, arrangement position, and the like of the “first through tube and the second through tube” can be appropriately determined. It also includes mere through holes in the tracheal tube wall. Further, the number of the first penetrating cylinder and the second penetrating cylinder is not limited to one, and a plurality of each may be provided.

The "first resonance muffling room" and "second resonance muffling room" are not limited to a particular shape or size as long as they have a volume necessary to resonate at a desired muffling frequency. A plurality of chambers may be provided according to the number of the first through-tube and the second through-tube. The “second molded body” may be formed by a known molding method such as injection molding, and as means for joining the second molded body to the first molded body, hot plate welding, vibration welding, Adhesion and the like can be exemplified.

[0010]

In the noise reduction device of the present invention, the first resonance noise reduction chamber of the first molded body and the second resonance noise reduction chamber of the second molded body communicating with the air duct each have a resonance noise reduction effect. Therefore, a plurality of silencing frequency bands can be obtained, and a sufficient reduction effect can be obtained even when the frequency range of noise is wide. In addition, both the first resonance silencing chamber and the second resonance silencing chamber are provided so as to surround the communication pipe (the first penetrating cylinder, the second penetrating cylinder, and the enclosing part), and the first molded body and the second molded body are arranged in a flow tube. This silencer can be made compact because it is adjacent to the air duct without being separated from it. In addition, since the first molded body is joined to the air duct at the same time as the blow molding, the number of steps and the number of parts are small, and the cost can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment in which the present invention is embodied in a silencer provided in an intake pipe of an internal combustion engine for an automobile will be described with reference to FIG.
This will be described with reference to FIG. Silencer 1 of the present embodiment
Is provided with an air cleaner hose 2, one first molded body 3 and one second molded body 4, and each member is configured as follows.

An air cleaner hose 2 serving as an intake pipe connecting an air cleaner of an internal combustion engine and a fuel injection device (both not shown) is blow-molded into a cylindrical shape using a synthetic resin such as polypropylene, polyamide, or polyethylene. It is made by injection molding. A first penetrating cylinder 5 and a second penetrating cylinder 6 are protrudingly provided at a position approximately 180 degrees apart from each other in the axial direction intermediate portion of the tube wall of the air cleaner hose 2. Each of the through-cylinders 5 and 6 is formed by cutting off the end surface after forming the outer end surface as a closed tube by the blow molding.

The first molded body 3 is formed by blow molding the outer peripheral surface of the air cleaner hose 2 using the synthetic resin as an insert part. The first molded body 3 bulges away from the air cleaner hose 2 in the lower half, and forms a first resonance silencing chamber 7 that surrounds the first penetrating cylinder 5 as a communication pipe to the air cleaner hose 2. In FIG. 1, a pedestal 8 for joining the second molded body 4 is formed at the peripheral edge of the upper surface of the first molded body 3 located on both shoulders of the first resonance silencing chamber 7 by the blow molding. The upper part of the first molded body 3 is in close contact with the air cleaner hose 2, and in particular, is provided with an enclosing portion 9 for enclosing the second penetrating cylinder 6 in an intimate state. Both ends of the first molded body 3 extend to both ends of the air cleaner hose 2, and form extended portions 10 which are in close contact with the outer peripheral surfaces of the both ends. An annular protrusion 11 is provided on the outer periphery of each extension portion 10 to improve the sealing performance when a hose (not shown) is externally fitted.

The second molded body 4 is injection-molded in a hat shape separately from the first molded body 3 using the above-mentioned synthetic resin. At the lower peripheral edge of the second molded body 4, a contact portion 12 abutting against the pedestal 8 is formed by the injection molding, and the contact portion 12 is joined to the pedestal 8 by hot plate welding. The second molded body 4 includes the second through-tube 6 and an encapsulation portion 9 having an end surface (referred to as an end surface enclosing the outer opening of the second through-tube 6) perforated with the air cleaner hose 2.
A second resonance silencer 13 is provided which surrounds as a communication pipe to the air. In addition, the perforation of the end surface of the enclosing part 9 is performed by the processing after the blow molding of the first molded body 3.

The muffler 1 of this embodiment is manufactured by the following procedure. The air cleaner hose 2 is molded by blow molding or injection molding, and the second molded body 4 is molded by injection molding. As disclosed in Japanese Patent Application Laid-Open No. 1-253559, the air cleaner hose 2 is set in a blow molding die (not shown), a parison is supplied around the air cleaner hose 2, and the die is tightened. Air is blown into the inside to blow-mold the first molded body 3. The end face of the envelope 9 of the first molded body 3 is pierced by drilling, cutting off, or the like. The hot plate welding is performed by aligning the contact portion 12 of the second molded body 4 with the base 8 of the first molded body 3.

In the muffler 1 of the present embodiment configured as described above, the first resonance muffler 7 and the second resonance muffler 1
The resonance frequency of 3 or the silencing frequency band f0 is represented by the following equation.

[0017]

F0 = (C / 2π) √ (S / (V · Lp)) where C = 331.5 + 0.61t: sound velocity (m /
Sec) S = πD ^2/4: cross-sectional area of the communicating pipe (inner size) D: inside diameter of the communicating pipe V: resonance silencer chamber volume Lp = L1 + 0.8D L1: length of the communicating pipe t: Temperature (℃)

In the present embodiment, the first resonance muffling chamber 7 and the second resonance muffling chamber 13 exhibit the resonance muffling action, respectively.
Two silencing frequency bands are obtained, and a sufficient reduction effect can be obtained even when the noise frequency range is wide. In addition, both the first resonance silencing chamber 7 and the second resonance silencing chamber 13 are provided so as to surround the communication pipe (the first penetrating cylinder 5, the second penetrating cylinder 6, and the enclosing part 9), and the first molded body 3 and the second Since the two molded bodies 4 are adjacent to the air cleaner hose 2, the silencer 1 can be formed compact. Further, since the first molded body 3 is joined to the air cleaner hose 2 at the same time as the blow molding, the number of steps and the number of parts are small, and the cost can be reduced.

Next, the silencer 2 of the second embodiment shown in FIG.
1, a first penetrating cylinder 5 and two second penetrating cylinders 6a, 6b project from the tube wall of the air cleaner hose 2; The second embodiment is different from the first embodiment in that it is swelled all around and two second molded bodies 4a and 4b are welded to the upper and lower parts of the first molded body 3 by hot plate welding. The first resonance muffling chamber 7 surrounds the first penetrating cylinder 5 as a communication pipe to the air cleaner hose 2, and the second resonance muffling chamber 13a of the second molded body 4a has a perforated end face with the second penetration cylinder 6a. The second resonance muffling chamber 13b of the second molded body 4b is formed as a communication pipe with the second through-bore 6b and the encapsulation part 9 having an end face perforated. Surrounding. In addition, about the member etc. common to a 1st Example, the common code | symbol is attached | subjected to FIG. 3 and description is abbreviate | omitted.

According to the present embodiment, the first resonance muffling chamber 7 and the two second resonance muffling chambers 13a and 13b exhibit the resonance muffling action, respectively. Two silencing frequency bands are obtained.

Next, the silencer 3 of the third embodiment shown in FIG.
Reference numeral 1 denotes two second molded bodies 4a, 4 on the upper part of the first molded body 3.
The second embodiment differs from the second embodiment in that b is hot plate welded side by side. Members and the like common to the first embodiment are given the same reference numerals in FIG. 4 and description thereof is omitted. According to the present embodiment, in addition to the same effects as the second embodiment, the radial bulkiness can be suppressed as compared with the second embodiment.

The present invention is not limited to the configuration of the above-described embodiment. For example, the present invention may be embodied in a silencer for an intake system or an exhaust system in various fluid utilization devices other than an internal combustion engine for an automobile.
The present invention can be arbitrarily modified and embodied without departing from the spirit of the invention.

[0023]

As described above, the silencer according to the present invention has a plurality of silence frequency bands, so that a sufficient reduction effect can be obtained even when the frequency range of noise is wide. An excellent effect is obtained that it can be made compact, the number of steps and the number of parts are small, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a muffler according to a first embodiment.

FIG. 2 is a partially cutaway front view of the muffler.

FIG. 3 is a sectional view of a muffler according to a second embodiment.

FIG. 4 is a sectional view of a muffler according to a third embodiment.

FIG. 5 is a front view of a conventional silencer.

FIG. 6 is a sectional view of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silencer 2 Air cleaner hose as a flow pipe 3 First molded body 4, 4a, 4b Second molded body 5 First penetrating cylinder 6, 6a, 6b Second penetrating cylinder 7 First resonance silencing chamber 9 Enclosure part 13, 13a, 13b Second resonance silencer 21 Silencer 31 Silencer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-253559 (JP, A) JP-A-53-30660 (JP, A) JP-A-6-159174 (JP, A) 85807 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02M 35/12 ZAB F01N 1/02 ZAB F02M 35/10 101

Claims (1)

(57) [Claims] 1. A flow tube having a first through-tube and a second through-tube protruded from a tube wall, and the first through-tube is formed by blow molding the outer periphery of the flow tube with the flow tube as an insert part. The first molded body having a first resonance muffling chamber that surrounds as a communication pipe to the air flow tube, and a wrapped portion that wraps the second through-tube in close contact with the first molded body, A second resonance muffling chamber which is formed into a body, and is joined to the first formed body, and surrounds the second penetrating cylinder and a wrapped portion whose end face is perforated as a communication pipe to the airflow tube. And a second molded body.