JPH04262013A - Muffler device - Google Patents

Abstract

PURPOSE:To set a side branch resonator type or interference type muffler device in a compact form to reduce the arrangement space. CONSTITUTION:A side branch resonator pipe 4 which communicates to an air flow conduit 3 or interference pipe is installed so as to be wound in spiral form on the outer periphery of the air flow conduit 3. Accordingly, the side branch resonator pipe 4 or interference pipe is set in small spiral form on the outer periphery of the air flow conduit 3, and the bulkiness in the lengthwise direction is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side branch resonance type or interference type muffling device for muffling noise generated in an air flow pipe.

0002

[Prior Art] Conventionally, as a muffling device for eliminating noise generated in a flow air pipe, there have been conventionally used;
There are known side branch resonance type muffling devices in which a side branch resonance tube is provided that communicates with the flow air conduit, and (2) an interference type muffler that is provided with an interference tube that communicates with the flow air conduit at both ends.

0003

[Problem to be Solved by the Invention] However, in the resonance type muffling device described in (iii) above, since the volume of the resonance muffling chamber is large, a large installation space is required near the air flow pipe, which is difficult to secure. Something happened. For example, a silencer installed in an intake pipe of an internal combustion engine of an automobile is installed in an engine room where many parts and pipes are crowded, so it has been difficult to secure a space for the installation. Also,
In the side-branch resonance type or interference-type silencer described in (1) or (2) above, it is sufficient to have a thin side branch resonance tube or interference tube, but on the other hand, if they are extended in a straight line, they become quite long, especially when the silencing frequency is low. is 100cm
Because of the above, it was still difficult to secure the space for installation. SUMMARY OF THE INVENTION An object of the present invention is to provide a muffling device that solves the above problems, can be made compact, and can reduce the space for its installation.

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a muffling device in which a side branch resonance pipe or an interference pipe communicating with an air flow pipe is wound spirally around the outer circumference of the air flow pipe. It is characterized by being provided so that it can be used.

[0005] Here, the "flow air pipe" is not limited to any particular pipe as long as it is a pipe through which gas flows, and may include, for example, an intake pipe or an exhaust pipe of an internal combustion engine. The "side branch resonance tubes or interference tubes" that are spirally wound around the outer circumference of the flow air conduit may be in contact with or separated from the flow air conduit, and the They may be in contact with each other or may be apart. Further, the cross-sectional shape of the side branch resonance tube or interference tube is generally circular or square, but other shapes may be used.

[0006]

[Function] According to the muffling device constructed as described above, the side branch resonance pipes or the interference pipes are gathered together in a small spiral shape around the outer periphery of the flow air pipe line, so that they are not bulky in the length direction. Therefore, the space for installing the silencer can be reduced.
For example, it can be easily installed in a narrow space such as the engine room of a car.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is embodied in a resonance type muffling device provided in an intake pipe of an internal combustion engine will be described with reference to FIGS. 1 to 3. The outer periphery of the air hose 3, which serves as an intake pipe connecting between the air cleaner 1 and the fuel injection device 2 of the internal combustion engine, has one end (the left end in FIG. 1) communicating with the air hose 3, and the other end (the right end) being blocked. A side branch resonance tube 4 is provided so as to be wound helically. Note that the side branch resonance pipe 4 and the air hose 3 are in contact with each other, and the side branch resonance pipe 4 is in contact with the air hose 3.
The spiral elements 4a are spaced apart from each other. Further, the side branch resonance tube 4 has a circular cross-sectional shape and an inner diameter of about 30 mm. Assuming that the length of this side branch resonance tube 4 is L1, its resonance frequency, that is, the silencing frequency f0 is expressed by the following equation 1.

[0008]

[Equation 1] f0 = (2n-1)C/4L1 Here, C
=331.5+0.61t: Speed of sound (m/sec) t: Temperature (°C) n =1,2,...

Therefore, if the frequency of the intake noise generated in the air hose 3 is, for example, a low frequency of 60 Hz,
In order to match the silencing frequency f0 to 60 Hz, the length L1 of the side branch resonant tube 4 at a temperature of 20° C.
It has to be quite long at 143cm. However, according to the silencer of the present embodiment, the side branch resonance pipe 4 is arranged in a small spiral shape around the outer circumference of the air hose 3.
It becomes less bulky in the length direction. Therefore, the space for installing the silencer can be reduced, and it can be easily installed in the engine room of an automobile.

Next, the second embodiment shown in FIG. 4 differs from the first embodiment only in that the interference pipe 5, which communicates with the air hose 3 at both ends, is provided so as to be wound spirally around the outer periphery of the air hose 3. This is different from the example. The effective length between both ends of this interference tube 5 (the length when the spiral is extended) is L1
The straight line distance between the openings at both ends of the interference tube 5, that is, the corresponding length of the air hose 3 corresponding to the interference tube 5, is L2.
Then, since interference occurs at a frequency where L1 - L2 is a half wavelength, the frequency of this interference, that is, the silencing frequency f
0 is shown by the following number 2.

[0011]

[Math 2] f0 = C/[2(L1 - L2)]

00
12] Therefore, if the frequency of the intake sound generated in the air hose 3 is, for example, 100Hz, the silencing frequency f
0 to match this 100 Hz, L1 - L2 must be 172 cm at a temperature of 20°C. Therefore, the corresponding length L2 of the air hose 3 is set to 4, for example.
If it is 0cm, the effective length L1 of the interference tube 5 is 212c.
It must be very long, m. However, according to the silencer of the present embodiment, the interference pipe 5 is spirally gathered around the outer periphery of the air hose 3 and is not bulky in the length direction, so that the same effect as in the first embodiment can be achieved.

It should be noted that the present invention is not limited to the configuration of the above-mentioned embodiments, and can be implemented with arbitrary changes without departing from the spirit of the invention, for example, as follows. (1) The side branch resonance tube 4 or the interference tube 5 is integrally molded with the air hose 3 from synthetic resin. (2) Two side branch resonance tubes 4 or two interference tubes 5 are provided around the outer periphery of the air hose 3 in a double spiral shape. (3) The side branch resonance tube 4 is constituted by a double tube consisting of an inner tube and an outer tube arranged coaxially. If the inner pipe is used as an outgoing route and the outer pipe is used as a return route so as to be continuous, the outer circumference of the air hose 3 can be further shortened. Furthermore, by using the inner tube and the outer tube in parallel and having different lengths, it is possible to provide two types of silencing frequencies.

[0014]

[Effects of the Invention] Since the silencer of the present invention is constructed as described above, it has the excellent effect that the silencer can be made compact and the space for its installation can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a side branch resonance type muffler according to a first embodiment.

FIG. 2 is a front view of FIG. 1.

FIG. 3 is a front view showing the installed state of the first embodiment.

FIG. 4 is a sectional view of an interference type muffler according to a second embodiment.

[Explanation of symbols]

3 Air hose as airflow pipe 4 Side branch resonance pipe 5 Interference pipe

Claims (1)

[Claims] 1. A silencer comprising: a side branch resonance tube or an interference tube communicating with an air flow pipe; and a side branch resonance pipe or an interference tube that is spirally wound around the outer circumference of the air flow pipe.