JPH01235499A - Silencer device for rotary machine sound - Google Patents

Abstract

PURPOSE:To surely silence the sound of a rotary machine at an objective spot to control by providing a phase regulating system which synchronizes a signal processed by a computing element with the rotational period of the rotary machine, and in addition, transmits it at an approximately constant phase against a rotational phase angle. CONSTITUTION:The sound of the rotary machine 12 received by a microphone 14 is converted into a digital signal by an A/D converter 16, and after being filtered, it is stored successively in the memory of the computing element 17. A sound signal stored in the memory is delayed than the sound generated by the rotary machine 12 by some phases. On the other hand, a trigger generator 19 outputs a trigger pulse at a predetermined rotary phase angle, eng this trigger pulse designates an address to be an output edge for reading data from the memory. Accordingly, if this read out address is set previously to be an optimum address determined for this system, a time lag caused by arithmetic operation and transmission, etc., can be perfectly compensated, and the sound of the rotary machine 12 comes to be canceled by the sound of a speaker 22 at the objective spot 13 to be controlled. Thus, the sound of the rotary machine at the objective spot to be controlled can be surely silenced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a muffling device that actively muffles rotating machine noise received at a point to be controlled.

(Prior Art) Many rotating machines generate noise, except for special machines. Such noise can cause various problems depending on the time and location. However, it is generally extremely difficult to configure a rotating machine so that no noise is generated.

For this reason, conventional methods have been considered to eliminate the sound of rotating machines at specific locations using acoustic methods. This method artificially generates sound waves that have the opposite phase and the same size as the rotating machine sound received at a specific location, and causes the one-rotation machine sound to interfere with the artificially created sound. I'm trying to turn off the machine noise.

FIG. 6 shows a schematic configuration of a conventional noise reduction device 1 that actively suppresses rotating machine noise as described above. In the figure, 2 indicates a rotating machine that is a sound source, and 3 indicates a control target point at which it is desired to mute the rotating machine sound. This muffling device 1 converts the sound generated by a one-rotation machine 2 into an electrical signal using a sound receiver such as a microphone 4, and transmits this signal to a human-powered signal from a sound generator such as a speaker 6 via an arithmetic unit 5 including a filter. I try to give it as such.

That is, the sound generated by the one-rotation machine 2 is 81 degrees, and the sound generated by the speaker 6 is 82 degrees. The sound received by the microphone 4 is R1, the sound at the control target point 3 is R2, and the acoustic transfer function between each point is Tll.

T21. T12. When T is 22, the following formula holds true as a two-man power two-output system.

Since this muffling device aims to reduce the sound level at the control target point 3 to zero, it can be set as R2-0. therefore.

52-(R1-TI2) BaT12・T21-TliT2
2). As can be seen from the above formula, to set R2-0, the sound received by microphone 4 should be R1.

F-T12/ (TI2・T21-Tll・T22)
. . . (1) It is sufficient to generate the sound S2 obtained by applying the filter from the speaker 6. The conventional silencer 1 employs the above-mentioned principle.

However, the conventional silencer 1 configured as described above has the following problems.

That is, the sound R1 received by the microphone 4 is a function R+(t) of one hour. On the other hand, since it is necessary to perform arithmetic processing, etc., a certain amount of time τ is required until 82 is actually determined. Therefore, as shown in Fig. 7, when the output S2 is determined, the value of R has changed, and there is a problem that the sound R2 at the control target point 3 cannot be completely zeroed out. there were.

(Problems to be Solved by the Invention) As mentioned above, in the conventional noise reduction device that actively suppresses the sound of a single-rotation machine, the sound produced by the two sound generators does not reach the point to be controlled. This takes a lot of time, and as a result, there is a problem in that it is not possible to satisfactorily muffle the rotating machine noise at the point to be controlled.

Therefore, the present invention can be achieved without complicating the configuration.

It is an object of the present invention to provide a rotating machine sound muffling device that can reliably muffle the rotating machine sound at a point to be controlled.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, in the silencer according to the present invention, a line for sending signals to a sound generator is synchronized with the rotation period of the rotary machine, and the rotation phase is It is equipped with a phase adjustment system that sends out at a constant phase with respect to the angle.

(Function) As can be seen from the waveform of the sound R1 received by the sound receiver shown in Fig. 7, the single-rotation machine sound repeats almost the same waveform in the rotation period. The device of the present invention focuses on this point.

Now, if one rotation period is T and one hour is t, the sound output of a one-rotation machine is 5l(t).

S 1 (t) - S 1 (t+nT). However, n
is an integer. In addition, the sound R1(t) received by the sound receiver,
Sound emitted from the generator to zero the sound at the control target point 5
2(t) and the time delay corresponding to the phase difference in the fundamental period is α, and the filter is F.

S2 (t) = F-R1 (t+α). As mentioned above, the sound R1(t) received by the sound receiver repeats at a period T, similar to the sound 5l(t) of the two-rotator.

S2 (t) = F-R1 (t+ nT+ a). The phase adjustment system incorporated in the silencer of the present invention is n
The sound before the cycle is synchronized with the rotation of the two-rotation machine, and the sound is emitted from the sound generator at a constant phase with respect to the nine-rotation phase angle. therefore.

It is possible to completely compensate for time delays and eliminate rotating machine noise at the point to be controlled.

(Example) An embodiment will be described below with reference to one drawing.

FIG. 1 shows a schematic configuration of a silencer 11 according to an embodiment.

In the figure, 12 indicates a rotating machine that is a sound source.

Reference numeral 13 indicates a control target point at which it is desired to mute the rotating machine sound. The sound S generated by the rotating machine 12 is converted into an electrical signal by a sound receiver, that is, a microphone 14, provided at a predetermined distance from the rotating machine 12. and,
After the output signal of the microphone 14 is amplified by the amplifier 15.

The signal is introduced into the arithmetic unit 17 via the A/D converter 16.

The arithmetic unit 17 sequentially writes into the memory the values obtained by applying the predetermined filter F expressed by the above formula (1) to the input signal, and then sequentially erases the previously written values. The memory stores, for example, a shift register of M bits in length.
It is attached to a separate building. That is, the memory is 1
The word is composed of N bits, and at least 3 of the pronunciations received by the microphone 14 at the rated rotation speed of the rotating machine 12
It is configured so that only M words corresponding to a cycle can be stored.

On the other hand, the two-rotation machine 12 is provided with a sensor 18 for obtaining a two-rotation amount period signal. This sensor 18 is constituted by an acceleration pickup or a voltage sensor that detects armature winding voltage when the rotating machine 12 is a synchronous motor. The output of this sensor is then introduced into a trigger generator 19.

This trigger generator 19 generates a trigger pulse at a preset rotational phase angle based on the output signal of the sensor 18. This trigger pulse is given as an address designation signal that serves as an output terminal for reading data from the memory built into the arithmetic unit 17. Therefore, for example, when address M-8 is specified, only the data that is successively sent to address M-3 is read out. and,
The data read from the memory, that is, the acoustic signal is D/
After being converted into an analog signal by the A converter 20, it is provided as an input signal to a speaker 22 that can be arranged in a fixed relationship with respect to the rotating machine 12 and the control target point 13 via an audio amplifier 21.

With such a configuration, as shown in the control algorithm in FIG.
After the sound is converted into a digital signal by an A/D converter 16 and filtered.

The data are sequentially stored in the memory within the arithmetic unit 17. Since A/D conversion and filtering require a certain amount of time, the acoustic signal stored in the memory lags behind the sound actually generated by the rotating machine 12 by a certain phase. On the other hand, the trigger generator 19 outputs a trigger pulse at a predetermined rotational phase angle.

This trigger pulse specifies the address that will be the output end for actually reading data from the memory. Therefore, if this readout address is set in advance to the optimal address determined by this system, the rotating machine 1 at the control target point 13
The sound coming from the speaker 22 is completely canceled out by the sound coming from the speaker 22, and the rotary machine sound at the control target point 13 can be muted. In other words, sensor 1
The 8° trigger generator 19 functions as a phase adjustment system that changes the phase of the sound output from the speaker 22 with respect to the phase of the one-rotation machine sound.

In the embodiment described above, the rotary machine 12 is provided with a sensor for obtaining a rotation synchronization signal, but as shown in FIG.
to extract the fundamental wave component.

Even if the trigger pulse is generated from the trigger generator 19 at a constant phase angle determined according to the period of this fundamental wave, good noise reduction can be achieved as in the previous embodiment. FIG. 4 shows the control algorithm of this device. Furthermore, FIG. 5 shows a modification of the embodiment shown in FIG. 1, and the same parts are indicated by the same reference numerals. In the embodiment shown in FIG. 1, a sensor 8 is provided on the rotary machine 12 to obtain a rotation synchronization signal, but in this modification, a synchronization signal is obtained directly from the power source 23 of the rotary machine 12. With this configuration, unlike the case where a sensor is used, the configuration is not affected by sensitivity, so the configuration can be simplified. Note that the control algorithm is almost the same as in FIG. 2.

[Effect of the invention] The device of the present invention is configured as described above.

Despite its simple configuration, it is able to completely compensate for time delays caused by calculations, transmission, etc.

As a result, the rotating machine noise at the point to be controlled can be effectively muffled.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of a rotating machine sound muffling device according to an embodiment, Fig. 2 is a diagram showing a control algorithm of the device, and Fig. 3 is a diagram showing a control algorithm of the device.
The figure is a schematic configuration diagram of a rotating machine sound muffling device according to another embodiment, FIG. 4 is a diagram showing the control algorithm of the same device, and FIG. FIG. 6 is a schematic diagram of a conventional rotary machine stand silencer, and FIG. 7 is a diagram for explaining problems with the conventional device. 11, lla... Silencer, 12... Rotating machine. 13... Control target point, 14... Microphone, 15
゜21...Amplifier, 16...A/D converter, 17.
...Arithmetic unit. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] By converting the sound generated by the rotating machine into a signal using a sound receiver, processing this signal using a computing unit, and then sending it to a sound generator to generate sound, the rotating machine sound at the control target point is actively suppressed. The silencing device for rotating machine noise as described above is provided with a phase adjustment system that synchronizes the signal processed by the arithmetic unit with the rotation period of the rotating machine and sends it out at a substantially constant phase with respect to the rotational phase angle. A rotating machine sound canceling device featuring: