JP2586398Y2 - Air duct with silencer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air duct with a silencer used in, for example, an intake system of an internal combustion engine.

[0002]

2. Description of the Related Art In a duct through which air flows, for example, an intake system of an internal combustion engine, a hollow container is provided near the duct.
In some cases, a relatively small-diameter communication pipe communicates with a duct, and a resonance type silencer is formed using a container as a resonance chamber. For example, the one disclosed in Japanese Utility Model Laid-Open No. 61-41818 is that. Alternatively, there is a type in which an expanded large-diameter portion is provided in the middle of a duct to form an expanded silencer. For example, Shokai 6
It is disclosed in Japanese Patent Publication No. 3-45016.

[0003]

These mufflers are effective in attenuating noise that is transmitted from a noise source such as an engine body through a duct. But the duct itself,
Alternatively, it is difficult for these mufflers to attenuate air column vibrations generated in a duct including a duct and an air cleaner connected to the ducts and resonance noise generated by the resonance.

Providing a container or a large-diameter portion that protrudes in one place in the vicinity of the duct as in the above silencer requires a large space, for example, when mounted on an automobile engine. It may be inconvenient.

[0005]

SUMMARY OF THE INVENTION The present invention provides a tubular cavity which is closed at both ends in parallel with a duct, connects the two with a communicating tube, and has a cross section of the communicating tube in a direction along an axis parallel to the duct. The shape is a flat shape having a long axis parallel to the duct, and the length of the long axis is set to 1/1 / the length of the duct.
2 or more.

[0006]

[Function] In the air duct with silencer of this invention, the cavity chamber acts as a resonance chamber for the noise from the noise source transmitted through the duct and acts as a resonator to attenuate the noise and reduce the emission of noise outside the duct. Let it. The noise reduction characteristics are determined by the volume of the cavity and the length and cross-sectional area of the communicating pipe.

Further, air column vibrations occur in the duct itself to cause resonance, and resonance is generated. This resonance is also attenuated by the silencer having a communicating pipe having a long cross section in the axial direction of the duct. . It is known that if a volume is provided to the antinode of air column vibration through a communication pipe, the sound due to the vibration is absorbed and attenuated, but the communication pipe of the silencer of this invention has a flat cross-sectional shape. And its long axis is one of the length of the duct
/ 2 or more, it is possible to provide a volume even for the longest wavelength of air column vibration, that is, a vibration that has an antinode at the center of the tube length. This is because it gives a volume to the part.

[0008]

FIG. 1 shows an embodiment. The duct 1 is an air intake duct attached to a front end of an air cleaner of an internal combustion engine, and has a tubular cavity 2 closed at both ends and arranged in parallel. The duct 1 and the cavity 2 are connected by a communication pipe 3,
The inside communicates. The cross-sectional shape of the communicating pipe 3 traversing the duct 1 and the cavity 2 is a pipe length c and a width b as shown in FIG. The communication pipe 3 has a flat oval cross section in the direction along the axis of the duct 1 and the cavity 2. The major axis has a length a and the minor axis has a width b. The length a of the long axis is set to be larger than 1/2 of the length L of the duct 1. In addition, the duct 1, the cavity 2, and the communication pipe 3 can be easily and integrally manufactured in one process by a blow molding method using a synthetic resin material.

[0009]

The air duct with the silencer of the present invention acts as a resonator for the noise transmitted from one end of the duct by the cavity chamber acting as a resonance chamber to perform a noise reduction function. Furthermore, the communicating pipe has a flat cross-sectional shape along the axial direction of the duct, and the length of the major axis in the axial direction is set to be at least half the length of the duct, so that the air column vibration generated by the duct itself is generated. Can be absorbed and attenuated, so that the silencing effect is extremely large.

[0010] Further, since it is composed of two parallel tubular bodies, the layout is easy when it is mounted on an automobile engine.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment.

FIG. 2 is a cross-sectional view perpendicular to the axis of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Duct 2 Cavity room 3 Communication pipe a Long axis length of communication pipe L Length of duct

Claims (1)

(57) [Scope of request for utility model registration] A tubular duct and a tubular cavity closed at both ends are provided in parallel with each other, and the two are communicated with each other by a communicating pipe. The cross-sectional shape of the communicating pipe in a direction along an axis parallel to the duct is defined by a duct. An air duct with a muffler, wherein the air duct has a flat shape having a major axis parallel to the length of the duct and the length of the major axis is at least half the length of the duct.