JPH086574A - Noise reducing device for mechanism having plural units - Google Patents

Abstract

PURPOSE:To enable reducing the noise of mechanism having plural machines by providing a sound pressure level memory storing a sound pressure level, an adjustable D/A converter and a phase difference memory storing a phase difference in each analog calculating means. CONSTITUTION:A frequency detected with a sensor 31 is converted into a voltage via an FV converter 41 to be inputted to an analog calculating means 81, which adjusts finely the rotational speed of a motor M2 in proportion to the inputted voltage via an inverter 72 to make it coincide with the rotational speed of a motor M1. As a result, the vibration frequency of a sieve F2 is controlled so as to become equal to the vibration frequency of a sieve F1. Then, a sound pressure level meter G allows the maximum value of noise among noises of the whole of a machine group to be stored as a sound pressure level in a memory provided in an analog calculating means 81 and besides respective outputs of sensors 31, 32 are inputted to a phase difference meter 51 and a phase difference is made to be stored in another memory of the means 81.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise reduction device for reducing noise such as audible sound and infrasound emitted from a plurality of mechanical devices.

[0002]

2. Description of the Related Art For example, a large vibrating sieve for separating earth and sand from excavated earth and sand mud used in a muddy water pressure shield work generates a sound of an ultra-low frequency of 20 Hz or less, and therefore a general soundproof house. It cannot be reduced even if covered with.
Therefore, sound insulation measures are taken by covering with thick (about 30 cm or more) concrete.

FIG. 7 and FIG. 8 show an example of such a sound insulation countermeasure embodiment. In FIG. 8, the numbers in circles are actual measurement values, and the numbers in squares are prediction values. In these figures, three vibration sieving devices are operating in the sound source room D, and the actually measured sound pressure level in the room was 116 dB. Therefore, when the sound pressure of the surroundings was predicted by assuming a sound insulation room N with concrete having a ceiling thickness of 50 cm and side wall thicknesses of 50 cm and 60 cm, at the E position on the same floor, it was the same as 96 dB when there was no sound insulation room, and the H on the second floor. From position 73 dB to 72 dB, J
The prediction result was that the position was only slightly reduced from 76 dB to 74 dB. Moreover, it was found that the construction cost of the sound insulation room N would be enormous, about 10 million yen. There is sound leakage through ventilation holes and door gaps. If it is attempted to prevent this sound leakage, the cost will be further increased. There is also a problem that the construction period is extended, the period for dismantling after the completion of construction, and the period for removal work are also great.

Further, if measures for the sound insulation room are not carried out in advance, it will be impossible to carry out the measures because they will become a problem during the construction work because of the large scale of the measures.

Therefore, when a plurality of vibrating screens are installed next to each other, the rotating shafts of the vibration generators of the adjoining vibrating screens are mechanically connected so that the vibrations have opposite phases, Japanese Patent Application No. 4-346358 proposed by the applicant of the present application proposes a method of interfering and canceling out-of-phase super low frequency sounds generated from adjacent vibrating screens. That is,
As shown in FIG. 9, the rotation shaft 1 of the vibration generator A and the vibration generator A1 having the same configuration (corresponding members are denoted by a suffix A
Is attached) with a rotary shaft 1A, which is connected by a joint B,
The unbalancers 2, 3, 3 and 5, 6, 6 of the rotary shaft 1,
Unbalancers 2A, 3A, 3A and 5A of the rotary shaft 1A,
The phases of 6A and 6A are shifted by 180 degrees. Therefore, as shown in FIG. 10, when the vibration generators A and A1 are operated, the vibration V in the right angle direction is generated in one device A, and the vibration V in the right angle direction 180 degrees out of phase in the other device A1. Since the vibration V1 is generated, the both vibrations are combined and canceled to reduce noise.

However, this method mechanically connects the rotary shafts of the two vibration generators, so that the rotary shafts are machined for connection, and the phases of the two unbalancers are reversed while confirming the positions of both balancers. There is a problem that the connecting work is troublesome. A technique for solving this problem is Japanese Patent Application No.
-9032. That is, as shown in FIG. 11, the rotary encoders 10 and 10A are attached to the pulley portions 7 and 7A of the vibration generators A and A1 adjacent to each other, and the signal of the phase sensor 11 for detecting the position of the rotating shaft, that is, the position of the unbalancer is detected. Enter the frequency count section 1
2. A control signal is output to the inverters 16 and 16A via a control device 15 which is mainly composed of a personal computer including an arithmetic unit 13 and a control unit 14 and which calculates the phase of each device to be shifted by 180 degrees. To adjust.

However, there are cases where three or more vibrating screens are used at the construction site, and even when two screens are used, as a result of experiments, noise may be reduced if the phase difference is not 180 degrees. The above technology cannot solve such a case.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide at low cost an apparatus for reducing the noise of a plurality of machines regardless of the number of machines and the phase difference.

[0009]

According to the present invention, a noise reduction device for a plurality of mechanical devices that generate noise is provided with adjacent first and second mechanical devices, and A sound pressure level meter for detecting a sound pressure level, a first sensor for detecting a vibration frequency of a first mechanical device, a second sensor for detecting a vibration frequency of a second mechanical device, and a first sensor From the first sensor and the second sensor, and the phase difference between the first mechanical device and the second mechanical device when the signal from the first sensor and the second sensor is input. The signals from the phase difference meter for detection, the sound pressure level meter, the FV converter, and the phase difference meter are input to the second mechanical device to make the first signal.
And an analog calculating means for outputting a phase difference between the first rotating machine and the first rotating machine to the inverter, the analog calculating means including a sound pressure level memory for storing a sound pressure level and an adjustable DA conversion. And a phase difference memory for storing the phase difference.

Further, according to the present invention, the analog calculating means stores the signals from the sound pressure level meter and the phase difference meter in the sound pressure level memory and the phase difference memory at predetermined time intervals, respectively. The sound pressure level memory and the phase difference memory are updated when the latest detected value of the level is lower than the previous detected value. .

Further, according to the present invention, another FV converter provided with a third mechanical device, to which a signal from the second sensor is input, and the second sensor and the third mechanical device are provided. Another phase difference meter that receives a signal from the third sensor and detects a phase difference between the second mechanical device and the third mechanical device, the sound pressure level meter, and the other FV.
A signal from the converter and the other phase difference meter is input to output another rotation speed equal to that of the second mechanical apparatus to the third mechanical apparatus and a phase difference with the second mechanical apparatus to another inverter. And an analog calculation means.

[0012]

As described above, according to the present invention, the vibration frequency of the first mechanical device of the two adjacent machines passes through the FV converter via the first sensor and is converted into a vibration frequency signal. The phase difference between the vibrations of the first and second mechanical devices is input to the analog calculation means, passes through the phase difference meter via the first and second sensors, and is input to the analog calculation means as a phase difference signal. The calculation result of the frequency and the phase difference is output to the inverter of the second machine. On the other hand, a sound pressure level signal from a sound pressure level meter arranged near all the mechanical device groups is input to the analog calculation means.

In this analog calculation means, when the signal from the phase difference meter is input and converted into the voltage by the DA converter, the data is finely adjusted manually and input to the inverter, and the second mechanical device is set to the first. If the sound pressure level from the sound pressure level meter is minimized while shifting the phase with the mechanical device, the noise is significantly reduced. The sound pressure level value with the minimum noise and the phase difference at that time are stored in the sound pressure level memory and the phase difference memory, respectively, and the second mechanical device vibrates at the same frequency with respect to the first mechanical device at all times. While maintaining the noise, the phase difference at which the noise is minimum is held.

Further, the analog calculating means stores the phase difference signal and the sound pressure signal at predetermined time intervals, and outputs the values input at the same time when the latest input value is smaller than the sound pressure level value at the previous measurement. When the inverter is provided with a function of inputting the phase difference as a target value, the inverter adjusts the rotation by giving a signal for shifting the phase difference to the second machine by the first machine. Since the target value of is updated every predetermined time, it is possible to immediately respond to changes in the load applied to the mechanical device, and it is possible to always keep noise to a minimum.

Next, when the third mechanical device is arranged, like the third mechanical device and any one of the two mechanical devices, the combination of the first mechanical device and the third mechanical device, Both are controlled to have the same phase, and in the combination of the second mechanical device and the third mechanical device, both are controlled to have opposite phases. That is, control is performed so that adjacent mechanical devices have opposite phases. In this way, the rotation of the third mechanical device is adjusted. Since the same operation is performed for the rest of the mechanical devices, noise can always be kept to a minimum regardless of how many machines are arranged.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a first mechanical device sieving F1 and a second mechanical device sieving F2 are arranged adjacent to each other and are operating. The sieves F1 and F2 are driven by motors M1 and M2 via rotary shafts 21 and 22, respectively. In order to detect the vibration frequency of the sieves F1 and F2, a first sensor (hereinafter simply referred to as a sensor) 3 is attached to each of the sieves F1 and F2 via the shafts S1 and S2.
First and second sensors (hereinafter, simply referred to as sensors) 32 are provided. The vibration frequencies of the sieves F1 and F2 are detected. Each of the sensors 31 and 32 may be, for example, one light-reflective tape provided on the outer periphery of the shaft or a plurality of light-reflective tapes at equal intervals, and a photosensor provided at a position facing each other. If the number is increased in this way, the detection accuracy is improved. In addition, the proximity switch sensor provided at one position or at a plurality of positions at equal intervals on the outer circumference of the rotary shaft, and the proximity switch sensor provided at a position facing each other may be of a magnetic type or an eddy current type.

Now, the frequency detected by the sensor 31 is
It is converted into a voltage via the FV converter 41 and input to the analog calculation means 81. The analog calculation means 81 is
The rotation speed of the motor M2 is finely adjusted in proportion to the voltage input via the inverter 72 so as to match the rotation speed of the motor M1. As a result, the vibration frequency of F2 is controlled so as to be equal to the vibration frequency of the sieve F1.

Here, the function of the analog calculation means 81 is shown in FIG.
It will be described in detail with reference to FIGS.

In FIG. 2, a sound pressure level meter G comprises a microphone G1, an amplifier G2, a rectifier G3 and a peak hold G4, and is provided in the analog calculating means 81 as the sound pressure level of the maximum value of the noise of all machine groups. It is stored in the memory MA of the memories 94.

On the other hand, each output 31P of the sensors 31 and 32
And 32P are input to the phase difference meter 51 and the phase difference is stored in the memory MB of the memory 94.

In FIG. 3, the output count DA converter 9 is shown.
6 and the adder 97 constitute an analog calculation means 81, and the vibration frequency of the motor M1 is input to the adder 97 as a voltage via the FV converter 41 and detected by the phase difference meter 51 to detect the motor. The phase difference between M1 and the motor M2 is output to the inverter 72 via the analog calculation means 81 to control the rotation of the motor M2.

FIG. 4 shows this phase control loop. In this figure, a phase difference θ from a phase difference meter (not shown) is output (step S1), and the phase difference θ and the preset value x are set. The magnitude is determined (step S2), and if the phase difference θ is equal to the set value x, the output does not change, but if the phase difference θ is smaller than the set value x, the output count is reduced (step S3), and the phase difference θ is If it is larger than the set value x, the output count is increased (step S4) and the set value x is updated. Thereafter, this new set value becomes the target value, and the phase difference θ of the target value shifts the phase of the motor M2. There is.

In FIG. 5, the output count of the DA converter 96 is offset output (step S10), and the data of the DA converter is finely adjusted manually. The sound pressure level is preset in the A memory when the maximum noise is shown (step S11). Next, it is determined whether or not the work is completed (step S12). If YES, sound pressure level s when noise is minimum
Is stored in the memory MA, the phase difference θ at that time is stored in the memory MB, and the updating of the target value of the phase difference is completed (S13). If NO, the phase difference θ1 is detected (step S14) and the sound pressure level s1 is detected (step S1).
Five). Next, it is determined whether or not the measured value s1 is smaller than the sound pressure level value s stored in the memory MA (step S1
6). If YES, the sound pressure level s1 is stored in the memory MA
(Step S17), the phase difference θ1 at that time is stored in the memory MB (step S18), and the updating of the target value of the phase difference is repeated. If NO, the process returns to step S12 again without updating. In this way, the fine adjustment of the data of the DA converter is performed and the set phase difference is rotated once to complete the process. The phase difference θ when the sound pressure level s is the minimum while the set phase difference is rotated once is input to the inverter 72. In this way, the two adjacent machines are operated so that the combined noise is minimized.

Next, as shown in FIG. 2, a calibration 95 and a gate OSC 98 are added to the analog calculating means 81, and the analog operating means 81 inputs them to the memory 94 at predetermined intervals. As described above, the memory 94 has the MA memory MA and the memory MB. This storage operation is performed at predetermined time intervals through the gate OSC 96 according to a command from the calibration 95. Therefore, instead of manually searching for a phase difference that minimizes noise as described above, an appropriate automatic operation is always performed. It is to find out the phase difference. As described above, it is desirable to store the sound pressure level and the phase difference at predetermined time intervals and switch to an appropriate update of the phase difference when the manual adjustment of the data of the DA converter is completed.

Further, a case where three sieves are operated will be described.

In FIG. 1, the members corresponding to the third mechanical device, ie, the sieve F3, that is, the motor, the sensor, the inverter, etc., have the same structure as the first and second members, so that the reference numeral is one digit. The number is set to 3 and the description is omitted. Since the sieves F2 and F3 are arranged next to each other, the rotation of F3 is adjusted to a vibration frequency equal to the vibration frequency of the sieve F2, and noise is detected while detecting the sound pressure level from the sound pressure level gauge G. So as to minimize
Using the analog calculator 82 and the inverter 73, the rotation of the sieve F3 is adjusted while maintaining an appropriate phase difference with respect to the sieve F2 through the same process as described above.

The same applies to the sieve F3 and a sieve (not shown) adjacent to the sieve F3.

In addition to the sieve F1, another sieve F
2, F3 ,. ． ． , The output of the first sensor 31 is connected to all the phase difference meters 51, 52 ,. ． ． May be input.

FIG. 6 is a graph showing changes in noise with the vertical axis representing the sound pressure level dB and the horizontal axis representing time. In this figure, three sieves were operated, and the data S, T, and U at the time of no control all showed the sound pressure level of 110 dB, but at the time of control P, Q, and R according to the present invention, It showed a low value of 92 to 94 dB.

[0031]

Since the present invention is constructed as described above, the phase difference is not limited to 180 degrees, and
There is an effect that it can be applied to more than one machine and the noise of a plurality of machines can be reduced at low cost.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating a memory of an analog calculation unit.

FIG. 3 is a diagram illustrating a DA converter of an analog calculation unit.

FIG. 4 is a flowchart showing a phase control loop.

FIG. 5 is a flowchart illustrating the update of the phase difference.

FIG. 6 is a graph showing the effect of the present invention.

FIG. 7 is a plan view of a site where the present invention is implemented.

FIG. 8 is a side view of FIG. 7.

FIG. 9 is a sectional view showing a conventional example.

FIG. 10 is a diagram illustrating an effect of a phase difference.

FIG. 11 is a configuration diagram showing another conventional example.

[Explanation of symbols]

 1, 1A, 21, 22, 23 ... Rotating shafts 2A, 3A, 5A, 6A ... Unbalancer 7, 7A ... Pulley section 10, 10A ... Rotary encoder 11 ... Phase sensor 12. .. Frequency counting unit 13 ... Calculation unit 14 ... Control unit 15 ... Control device 31, 32, 33 ... Sensor 31P, 32P ... Sensor output 41, 42 ... FV converter 51, 52 ... Phase difference meter 72, 73 ... Inverter 81, 82 ... Analog computing means 94, MA, MB ... Memory 95 ... CAL 96 ... Output correction DA converter 97 ... -Adder 98 ... Gate OSC A, A1 ... Vibration generator B ... Joint D ... Sound source room E, H, J ... Measurement position F1, F2, F3 ... Machine device Sieve G ... Low frequency sound pressure level meter G1 ... Microphone G2 ... Amplifier G3 ... Rectifier G4 ... Peak hold K ... Wiring M1, M2, M3 ... Motor N ... Sound insulation room P, Q , R ... Sound pressure level during control S, T, U ... Sound pressure level during non-control V, V1 ... Vibration

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuya Ota 2-19-1 Tobita, Chofu, Tokyo Kashima Construction Co., Ltd. Technical Research Institute (72) Inventor Tadaaki Kaneko 4-chome, Ota-cho, Naka-ku, Yokohama, Kanagawa Address: Kashima Construction Co., Ltd., Yokohama Branch (72) Inventor Kenichi Kamijo 4-51, Ota-cho, Naka-ku, Yokohama-shi, Kanagawa Kashima Construction Co., Ltd., Yokohama Branch (72) Inventor, Norihiko Iwata, 4 Ota-cho, Naka-ku, Yokohama-shi, Kanagawa 51-chome, Kashima Construction Co., Ltd., Yokohama Branch (72) Inventor, Hiroshi Osugi, 3-4, Chuo, Nakano-ku, Tokyo Kokori Search Co., Ltd. (72) Yasufumi Yamagata, 3-chome, 4-chome, Nakano-ku, Tokyo No. Cocori Search Co., Ltd.

Claims (3)

[Claims] 1. A noise reduction device for a plurality of mechanical devices that generate noise, comprising a first mechanical device and a second mechanical device provided adjacent to each other, and detecting the sound pressure level of all mechanical devices. A first sensor that detects the vibration frequency of the first mechanical device, a second sensor that detects the vibration frequency of the second mechanical device, and a signal from the first sensor that is input to determine the vibration frequency. An FV converter for converting into a voltage, a phase difference meter for detecting a phase difference between the first mechanical device and the second mechanical device by receiving signals from the first sensor and the second sensor, and the sound pressure Signals from the level meter, the FV converter, and the phase difference meter are input to the second mechanical device so that the rotation speed equal to that of the first mechanical device and the first mechanical device can be obtained.
Of the mechanical device for outputting the phase difference to the inverter, the analog calculating means includes a sound pressure level memory for storing the sound pressure level, an adjustable DA converter, and a phase difference memory for storing the phase difference. And a noise reduction device for a plurality of mechanical devices. 2. The analog calculation means stores signals from the sound pressure level meter and the phase difference meter in a sound pressure level memory and a phase difference memory, respectively, at predetermined time intervals, and the latest detected value of the sound pressure level. 2. The noise reduction device for a plurality of mechanical devices according to claim 1, wherein the sound pressure level memory and the phase difference memory have a function of being updated when is lower than the previously detected value. 3. An FV converter having a third mechanical device, to which a signal from the second sensor is input,
Another phase difference meter, which receives a signal from a third sensor provided in the second sensor and the third mechanical device and detects a phase difference between the second mechanical device and the third mechanical device, Signals from the sound pressure level meter, the other FV converter, and the other phase difference meter are input to the third mechanical device so that the rotation speed equal to that of the second mechanical device and the position of the second mechanical device. The noise reduction device for a plurality of mechanical devices according to claim 1, further comprising another analog calculation means for outputting the phase difference to another inverter.