JPH11102192A - Soundproof structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a sure soundproofing for the door part of a casing by allowing a soundproof structure to have a sound generator which is provided in a space formed between a first door and a second door and outputs a sound having a phase opposite to that of noise to be released from this space to the outside of the casing through the second door. SOLUTION: This soundproof structure is provided for the door part of the casing wall 10 of a casing housing a noise generating source inside. A door part constituted of a first door (an inside door) 1 and a second door (an outside door) 2 is provided at the opening formed in the casing wall 10 forming the casing. Moreover, a speaker (sound generator) 5 and also a microphone (sound phase detector) 6 are respectively provided at the left side and the right side of a space to be formed between the inside door 1 and the outside door 2. Then, the vibration surface of the speaker 5 is directed toward the direction of the central part of the space and, consequently, a sound to be generated from the speaker 5 is emitted into the space. Moreover, the speaker outputs a sound having a phase opposite to that of noise, that is, a sound having a reverse wavelength.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproof structure for preventing noise from being emitted from the inside of a housing to the outside of the housing via a door provided on the housing.

[0002]

2. Description of the Related Art For example, in a system using an internal combustion engine such as a diesel engine generator, noise is generated during operation of the internal combustion engine. For this reason, a configuration for accommodating the internal combustion engine in a housing and reducing or preventing the influence of such noise on the environment has been widely adopted. In addition, the above-described housing is generally provided with a door portion for entering and exiting the inside and outside of the housing.

However, in the case having the door as described above, it is difficult to prevent noise from leaking from the door, and it is particularly difficult to prevent sound from leaking from the packing portion.
Conventionally, in order to cope with such sound leakage at the door portion, for example, a structure in which the thickness of the door portion is increased or concrete is inserted inside the door portion to increase the transmission loss amount at the door portion Has been adopted. In addition, there is also a case where a structure that prevents sound leakage from a gap between the door portion and the housing body by adopting a double or triple packing structure for a packing portion provided between the door portion and the housing body. is there.

[0004]

However, the level of noise generated by the internal combustion engine is very large, for example, 10
It reaches 0 to 110 dB. For this reason, even when the above-described conventional structure is employed, when the noise is large, such as in a diesel engine generator, sufficient soundproofing, for example, 4
The noise level cannot be reduced to 5 dB class.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a soundproof structure capable of surely preventing sound at a door portion of a housing.

[0006]

The soundproofing structure of the present invention comprises:
A first door located inside the housing, wherein the first door is used in a door portion of a housing that houses a noise generation source and prevents noise emission from the door portion to the outside of the housing; A second door located outside the housing, provided in a space formed between the first door and the second door, from the space to the outside of the housing via the second door A sound generator that outputs a sound having the opposite phase to the emitted noise.

In a preferred embodiment of the above soundproofing structure, the soundproofing structure further includes a detector for detecting a phase of the noise generated from the noise source, and the sound output from the sound generator based on a detection output of the detector. The phase of the output sound is feedback-controlled.

Further, the soundproof structure of the present invention is used for a door of a housing for accommodating a noise source, and for preventing noise from being emitted from the door to the outside of the housing.
A first door located inside the housing, a second door located outside the housing, provided in a space formed between the first door and the second door, From the space to the second
And a resonator that absorbs noise emitted to the outside of the housing via the door.

Further, in the present invention, preferably, at least the first door of the first door and the second door is provided.
Doors are made of damping steel. Since the first door, or the first and second doors are made of a damping steel plate in this way, the first or second door does not vibrate due to noise (vibration) in the housing. It can be prevented from becoming a secondary sound source.

[0010] In the present invention, of the noise generated from the noise source, particularly high-frequency components are blocked by a space (usually an air layer) formed between the first door and the second door. In particular, the low frequency component is A
The sound is muted by NC (active noise control) or muted by the above-described resonator. With these configurations, it is possible to prevent noise in the housing from leaking outside through the door.

The resonator has a function of utilizing resonance to absorb noise of a frequency component corresponding to a resonance frequency (frequency) from noise.

[0012]

Embodiments of the present invention will be described below.

FIG. 1 shows a soundproof structure according to an embodiment. This soundproof structure is provided on a door portion of a housing wall 10 of a housing in which a noise source (not shown) is accommodated. In addition,
The noise source is, for example, a system that uses an internal combustion engine that generates noise during operation of a diesel engine, a gasoline engine, or the like.

In FIG. 1, an opening formed at a predetermined position of a housing wall 10 having a predetermined thickness for forming a housing includes:
A door unit including an inner door (first door unit) 1 and an outer door (second door unit) 2 is provided. The inner door 1 and the outer door 2 are made of a damping steel plate. It should be noted that only the inner door 1 may be made of a damping steel plate.

A hinge 41 is provided between the right end of the inside door 1 and the inside of the opening of the housing wall 10 in the drawing. The hinge portion 41 allows the inner door 1 to be opened and closed around the hinge portion 41 as a rotation center, as shown by OPEN1 in FIG.

A hinge 42 is provided between the right end of the outer door 2 and the outer portion of the opening of the housing wall 10 in the drawing. The outer door 2 is pivoted about the hinge 42 by the hinge 42 in FIG.
It has a structure that can be opened and closed as indicated by N2.

A packing 3 made of rubber or the like is provided between the inner door 1 and an inner portion of the opening of the housing wall 10.
1, 32 are provided. Then, in a state where the inside of the opening of the housing 1 is closed by the inside door 1, the space between both ends of the inside door 1 and the inside of the opening is sealed. Outside door 1
Similar packings 33 and 34 are also provided between the outer door 2 and the inner and outer portions of the opening of the housing wall 10. The space between both ends and the outside of the opening is sealed.

Further, in the space formed between the inner door 1 and the outer door 2, a speaker (sound generator) 5 is located on the left side in FIG. 1, and a microphone (sound phase detector) is located on the right side.
6 are provided respectively.

The vibration surface of the speaker 5 is directed toward the center of the space, so that the sound generated from the speaker 5 is emitted into this space. The speaker 14 outputs a sound having a phase opposite to that of the noise, that is, a sound having an opposite wavelength, as described later.

The microphone 6 has a phase of noise transmitted from the noise source inside the housing surrounded by the housing wall 10 through the inner door 1 into the space, particularly a phase of a low frequency component in the noise. Is to be detected. Then, the output of the microphone 6 is fed back to a control circuit (not shown) of the speaker 5. The control circuit controls the driving of the speaker 5 so that the sound having the opposite phase to the noise detected by the microphone 6 is output from the speaker 5.

In the embodiment having the above configuration, during operation of the system, noise is generated from a noise source provided inside the housing, and the noise is transmitted through the inner door 1 to the inner side. It is transmitted to the space between the door 1 and the outer door 2. The high frequency component of the noise from the noise source is blocked by the inner door 1 and the outer door 2 and is prevented from being emitted to the outside of the housing.

When the low-frequency component of the noise is transmitted into the space, the sound is muted by the feedback control by the speaker 5 and the microphone 6 provided in the space, and is transmitted through the outer door 2. Transmission to the outside of the housing is prevented.

In the above, the low frequency component of noise transmitted from the inside of the housing to the space between the inner door 1 and the outer door 2 via the inner door 1 provided at the opening of the housing wall 10 is described. Speaker 5
This is a configuration example in which the sound is muted by feedback control by the microphone 5 and the microphone 6, but instead of the feedback control by the speaker 5 and the microphone 6, a resonator is provided in the space, and the low frequency component of noise is absorbed by the resonator. It is also possible to adopt a configuration in which In this case, by appropriately changing the resonance frequency of the resonator, it is possible to selectively absorb noise of a desired specific low-frequency component.

[0024]

According to the present invention, as described above, according to the present invention, it is possible to provide a soundproof structure capable of reliably soundproofing a door portion of a housing.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a soundproof structure according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inside door 2 Outside door 5 Speaker 6 Microphone 10 Housing wall

Claims (5)

[Claims] 1. A soundproof structure that is used for a door of a housing that houses a noise generation source and that prevents noise from being emitted from the door to the outside of the housing. A first door, a second door located outside the housing, a space provided between the first door and the second door, and the second door is provided from the space. A sound generator that outputs a sound having a phase opposite to that of noise emitted to the outside of the housing via the sound generator. 2. The apparatus according to claim 1, further comprising: a detector for detecting a phase of noise generated from the noise source, wherein a phase of a sound output from the sound generator is feedback-controlled by a detection output of the detector. The soundproofing structure according to claim 1, wherein 3. The soundproofing structure according to claim 1, wherein at least the first door of the first door and the second door is made of a damping steel plate. 4. A soundproof structure used for a door of a housing for accommodating a noise generating source and for preventing noise emission from the door to the outside of the housing, wherein a soundproof structure located inside the housing is provided. A first door, a second door located outside the housing, a space provided between the first door and the second door, and the second door is provided from the space. And a resonator that absorbs noise emitted to the outside of the housing through the housing. 5. The soundproofing structure according to claim 4, wherein at least the first door of the first door and the second door is made of a damping steel plate.