JPH07271382A - Silencer - Google Patents

Abstract

PURPOSE:To attenuate and erase noises of a wide range by correcting the residual noises to sound pressure level or waveform in which the residual noises are erased in accordance with the noises inputted from a noise detector and emitting sound waves from speakers for additive sounds when the noises fail to be completely erased by the sound waves generated from the speakers for the additive sounds. CONSTITUTION:The noises generated by an engine E are inputted as noise signals to a silencing controller 6. This silencing controller 5 forms the waveforms of the same sound pressure level as the sound pressure level of the inputted noise signals and the antiphases thereof and emits these waveforms from the additive sound speakers 2 into an engine room 3, thereby attenuating and erasing the noises generated in the engine E. The residual noises which fail to be completely erased by these sound waves are detected by a residual noise detecting sensor 10 and are inputted as residual noise signals to the silencing controller 5. The silencing controller 5 corrects the sound pressure level and waveforms of the sound waves emitted from the speaker 2 for the additive sounds in such a manner that the residual noise signals in the engine room 3 are erased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffling device which muffles noise with sound waves having the same sound pressure level and the same waveform and opposite phases.

[0002]

2. Description of the Related Art Generally, an engine of a ship produces noise when it is driven. Then, this noise propagates to the passenger compartment and makes passengers uncomfortable.

With respect to such noise generated from the engine, for example, a sound absorbing material is applied to the engine room to absorb the noise to suppress the noise propagating to the passenger compartment,
Alternatively, the wall of the engine room is made thick or the wall is made of high-density material to prevent noise from leaking to the outside of the engine room.

[0004]

As described above, when the sound absorbing material is applied to the engine room to absorb the noise, the low frequency noise leaks from the engine room to the outside through the sound absorbing material. I will end up.

Further, if the wall of the engine room is made thick or the wall is made of a high-density material, the weight of the entire ship increases, so that it is particularly suitable for a ship that is required to be lightweight, such as a high-speed ship. Absent.

Therefore, an object of the present invention is to provide a silencer capable of solving the above problems.

[0007]

Means for solving the problems of the present invention is to muffle noise generated by a noise generating section installed in a room by sound waves having the same sound pressure level and the same waveform and opposite phases. In the silencer that is
An additional sound speaker arranged in the room for generating the sound wave, a residual noise detection sensor arranged in the room for detecting residual noise that cannot be completely silenced by the sound wave, and the residual noise detection sensor. And a sound deadening controller having a function of correcting the sound pressure level and the waveform of the sound wave generated from the additional sound speaker on the basis of the residual sound detection signal from.

[0008]

In the above structure, when the noise generating section is driven to generate noise in the room, the noise signal is input to the muffling controller, and the muffling controller has the same sound pressure level and the opposite phase of the input detection signal. By creating a waveform and generating sound waves with the same sound pressure level and the same waveform and opposite phase as the generated noise from the additional sound speaker in the room, the sound waves and the noise generated by the noise generation part cancel each other out When the residual noise that is not completely erased by this sound wave is generated by the residual noise detection sensor, the residual noise detection sensor detects this residual noise and the residual noise signal detected by the residual noise detection sensor is input to the muffling controller. Based on this residual noise signal, the muffling controller corrects the sound pressure level and waveform of the sound wave emitted from the additional sound speaker so that the residual noise in the room is eliminated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the silencer of the present invention will be described below with reference to the overall configuration diagram of FIG. 1. This silences noise accompanying driving of an engine E generated when a vehicle 1 (for example, a high-speed ship) is traveling. A pair of left and right large-capacity additional sound speakers 2 for generating sound waves that muffle the noise are installed above the engine room 3 and above the wall 3A of the engine room 3. A pair of residual sound detection sensors (also referred to as error microphones) 10 for detecting residual noise that has not been completely silenced by the sound waves is attached.

The wall 3A is provided with a sound absorbing material 3B for preventing high frequency noise generated by driving the engine E from leaking to the outside of the engine room 3.
Has been applied.

Further, the additional sound speaker 2 generates a sound wave having the same level and the same waveform as the noise but an opposite phase, and the sound pressure level of the sound wave is generated based on the residual sound detection signal from the residual sound detection sensor 10. Also, a mute controller (for example, a digital signal processor or the like) 5 having a function of correcting the waveform is provided.

A vibration generator of the engine E, which is a noise source, and a rotation pulse generator (a noise source of low frequency) of the engine E, which are noise sources, are connected to the input side of the muffling controller 5 through an amplifier 7A. The residual sound detecting sensor 10 is connected, and the additional sound speaker 2 is connected to the output side of the muffling controller 5 via an amplifier 7B.

In the above structure, the transfer function of the sound from the additional sound speaker 2 to the engine room 3 is checked in advance by experiment and stored in the muffling controller 5. When the engine E is driven and noise is generated, the noise signal is input to the muffling controller 5, and the muffling controller 5 creates a waveform of the same sound pressure level and the opposite phase of the input detection signal, and first. A sound wave having the same sound pressure level, the same waveform, and opposite phase as the generated noise is emitted into the engine E by emitting the additional sound speaker 2 by applying the inverse function of the obtained transfer function.

By doing so, the sound waves emitted from the additional sound speaker 2 and the noise generated by the engine E cancel each other, and the noise is attenuated and eliminated. By the way, when the residual noise that cannot be completely erased by the sound wave is generated, the residual noise is detected by the residual noise detecting sensor 10.
To detect. The residual noise signal detected by the residual noise detection sensor 10 is input to the muffling controller 5 so that the muffler controller 5 erases the residual noise signal in the engine room 3 based on this residual noise signal. Speaker for additional sound 2
Correct the sound pressure level and waveform of the sound wave emitted from.

That is, a sound wave for attenuating and eliminating the noise is emitted from the additional sound speaker 2, but when the residual noise detecting sensor 10 detects the residual noise after that, it is determined from the noise of the vibration generating portion and the pulse generating portion. Waveforms are not suitable for attenuating and canceling propagation noise,
The muffling controller 5 corrects the waveform obtained based on the noise input from the vibration generating unit and the pulse generating unit to a sound pressure level and a waveform that can eliminate residual noise, and emits it from the additional sound speaker 2. To

Further, of the noise generated by the driving of the engine E, the high frequency reflected sound reflected in the engine E can be prevented from being absorbed by the sound absorbing material 3B and leaking to the outside of the engine E.

As described above, according to the embodiment of the present invention, when noise that cannot be completely erased by the sound wave generated by the additional sound speaker 2 is generated, the muffling controller 5 generates the vibration generator and the rotation pulse generator. The noise generated by the engine E is corrected by correcting the waveform obtained from the signal of the part to a sound pressure level and a waveform capable of eliminating the residual noise input from the residual noise detection sensor 10 and emitting the corrected sound from the additional sound speaker 2. The noise is attenuated and erased, and the noise is attenuated and erased in the engine room 3 where the noise is generated, so that the noise can be prevented from propagating to the passenger compartment and the like, and the noise can be attenuated and erased over a wide range.

Further, since the thickness of the wall 3A of the engine E is not increased or the material is not changed, it is possible to prevent the entire ship from becoming heavy. In addition, although the example in which the silencer is used in the ship has been shown in the above-described embodiment, the present invention is not limited to this. It can also be applied to control.

[0019]

As is apparent from the above description, according to the present invention, when the noise which cannot be completely erased by the sound wave generated by the additional sound speaker is generated, the muffling controller is input from the noise detector. Based on the noise signal, the sound wave is controlled to be emitted from the additional sound speaker after being corrected to a sound pressure level and waveform capable of eliminating residual noise, so that the noise generated in the noise generating section in the room is attenuated over a wide range.
Can be erased.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a silencer showing an embodiment of the present invention.

[Explanation of symbols]

 1 Vehicle 2 Speaker for Additional Sound 3 Engine Room 3A Wall 5 Noise Reduction Controller 7A Amplifier 7B Amplifier 10 Residual Noise Detection Sensor E Engine

Continued Front Page (72) Inventor Mitsuru Mizuuchi 5-3-3, Nishikujo 5-3, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd.

Claims (1)

[Claims] 1. A muffler for suppressing noise generated by a noise generator installed in a room with sound waves having the same sound pressure level and the same waveform and opposite phases, and the sound waves are arranged in the room Based on the residual sound detection signal from the residual noise detection sensor for detecting the residual noise that is placed in the room and is not completely silenced by the sound waves And a sound deadening controller having a function of correcting the sound pressure level and the waveform of the sound wave generated from the additional sound speaker.