JP2006276455A - Motor siren - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor siren which has proper sound production efficiency and can be made small in size, reduced in power consumption and extended in sound coverage. <P>SOLUTION: The motor siren comprises a plurality of sound-emitting parts 2, 2... which are driven by a single revolving shaft 1 and are different by the sound emission frequencies. The motor siren comprises a plurality of synchronously rotating fan rotors 3, 3... which are stored, respectively in rotor casings 5 provided with the different numbers of air inlet windows 4, or comprises a plurality of fan rotors 3, 3... which are provided with a different number of rotating blades 6 and are rotated synchronously and are stored, respectively in the rotor casing 5 provided with wind inlets 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor siren.

  Conventionally, what was described in patent document 1 is known as a motor siren. In this conventional example, the motor siren is formed by attaching a fixed cylinder to the outer periphery of the fan. The fan is formed in a substantially cylindrical shape by covering a plurality of radially extending blades with a cover, an opening corresponding to each blade is provided on the outer peripheral surface of the cover, and an intake port is provided on one end surface. In addition, an opening is provided on the outer peripheral surface of the fixed cylinder in the same manner as the fan. Therefore, when the fan rotates and air sucked from the intake port is released from the opening, the air is intermittently interrupted by the opening of the fixed cylinder. Is cut off and a sound is generated.

In addition, Patent Document 1 described above describes a polyphonic siren device configured by attaching a large number of the motor sirens. This multi-voice siren device is formed by connecting a siren unit composed of a pair of motor sirens to a drive motor via a shaft coupling and a speed reducer, and simultaneously produces a plurality of sounds having different pitches.
Japanese Utility Model Publication No. 2-44797

  However, the polyphonic siren device has a drawback of poor pronunciation efficiency. That is, in general, the sound-increasing effect due to sound interference is achieved by synthesizing and increasing the amplitude of each other by superposition of sound waves. However, if a siren unit is connected to the drive motor via a shaft coupling, Since sound waves having the same frequency are simultaneously generated from a number of sound sources having different positions, the sound waves always overlap with each other while maintaining a state in which a phase is shifted by a certain amount. Therefore, the sound generation efficiency is poor because the so-called waveform peaks are not strengthened by overlapping each other.

  In this regard, Patent Document 1 proposes to further provide a sound collecting plate and a reflecting plate, or to connect some of the siren units via a speed reducer. As a result, the apparatus is unnecessarily enlarged.

  The present invention has been made to eliminate the above drawbacks, and an object of the present invention is to provide a motor siren with good sound generation efficiency.

According to the present invention, the object is
This is achieved by providing a motor siren having a plurality of sounding portions 2, 2... Driven by a single rotating shaft 1 and having different sounding frequencies.

  In the present invention, the motor siren intermittently discharges air compressed by a fan rotor or a rotating disk that is rotationally driven with a vent hole into the outside air, and generates a sound wave that generates air density waves, that is, sound waves. 2 is included. A plurality of sound waves having different frequencies are generated at the same time by differentiating sound generation frequencies in a plurality of sound generating units 2, and these phases coincide with each other at a predetermined cycle so that peaks of waveforms overlap each other. Can obtain the maximum amplitude, that is, the maximum volume. In addition, by connecting a plurality of fan rotors or the like to the common rotating shaft 1 to synchronize the plurality of sound generating units 2 with the single rotating shaft 1, the driving efficiency can be increased and the apparatus can be made compact. Can be. Accordingly, it is possible to provide a motor siren that emits a large volume with a small device.

  The efficient sound enhancement effect by synthesizing sound waves with different frequencies can be caused by, for example, so-called sound beats with a small difference in frequency. However, it utilizes the fact that the wind noise generated by the motor siren is a composite sound. Thus, it is possible to superimpose appropriate frequency components included in each sound wave, and in this case, it is possible to appropriately determine the relationship between the frequency components in each sound wave by experiment. According to the inventor's experiment, when the frequency relationship in each sound wave (combined wave of multiple frequency components) is set to approximately 2: 3, that is, when the frequency is approximately 1.5 times to generate a chord. It has been confirmed that a sound-increasing effect of a few decibels can be obtained as compared with a case where sound waves having the same frequency as in the conventional example are superimposed. In this way, when the frequency difference that can provide an efficient sound-increasing effect satisfies the chord condition, a harmonious and comfortable large sound can be obtained.

  When a plurality of sound generating units 2 are driven by a single rotating shaft 1, for example, fan rotors as sound generating units 2 are arranged on both sides of a motor as a power source of the rotating shaft 1, or one side of the motor It is possible to configure a motor siren by connecting a fan rotor or the like to the fan. In this case, when the pair of sounding portions 2 are evenly arranged on both the left and right and upper and lower sides of the motor, that is, when the sounding portions 2 are arranged at both ends of the rotating shaft 1, the sounding portions 2 are continuously provided on one side of the motor. As a result, the overall balance can be increased, and a plurality of rotating fan rotors and the like can be supported relatively easily and stably.

Further, as described above, when the sound generation frequencies of the plurality of sound generating units 2, 2,... Are made different, specifically, it is possible to control the number of rotations of the fan rotor or the like as in the conventional example. However, the motor siren can be configured more simply by changing the fan rotor and the rotor casing that houses the fan rotor. That is,
Each of the plurality of fan rotors 3, 3... That rotate synchronously is housed in a rotor casing 5 in which different numbers of wind cut windows 4 are opened,
Or
Each of the plurality of fan rotors 3, 3,... Each having a different number of rotating blades 6 and rotating synchronously is housed in a rotor casing 5 in which a wind cut window 4 is opened, thereby producing a plurality of sound generations having different sound generation frequencies. The parts 2, 2,... Can be easily configured.

  That is, since the sound wave, which is an air density wave, changes the frequency, which is the frequency, by changing the number of density times per unit time, specifically, the rotor casing 5 that houses the fan rotor 3. The frequency can be easily changed by changing the number of times the airflow emitted from the air is divided. Therefore, by changing only the number of the wind cut windows 4 and the number of the rotary blades 6, the number of times the air current is divided per unit time can be easily changed in the plurality of sound generating units 2, and the sound generation frequencies can be varied. .

  In addition, the sound generation efficiency of the motor siren can be enhanced by using sound generation from the air inlet 8 of the fan rotor 3 and the rotor casing 5 in addition to sound generation by the release of the air dense wave from the wind cut window 4. Is possible. That is, as described in Patent Document 1, the sound emitted from the intake port 8 generally interferes so as to weaken the sound emitted from the wind cut window 4 because the phase is inverted as it is. However, by providing the phase adjustment guide 7 in the intake port 8 to bypass the sound wave, it is possible to cause interference by adjusting the phase and enhancing the sound. The shape of the phase adjusting guide 7 can be determined as appropriate by experiment. According to the inventors, the sound pressure changes according to the linear distance from the air inlet 8, and the shape of the phase adjusting guide 7 is outward. It has been confirmed that the sound pressure can be further increased when it is formed into a flared shape that gradually expands toward the surface as compared with when it is formed into a cylindrical shape.

  As is apparent from the above description, according to the present invention, a motor siren with good sound generation efficiency can be provided, and the motor siren can be reduced in size, saved in power, and improved in sound range.

  1 to 3 show an embodiment of the present invention. In this embodiment, the motor siren is omnidirectional with a pair of sounding parts (sounding part 2) arranged on the left and right sides of the motor 11, and is placed on a flat place via a support base 13 that supports the motor case 12. It is configured to be installable. In FIG. 1, a box-like 14 formed on the side of the motor case 12 is a terminal box for connecting a cable of the motor 11 and a lead-out cable (not shown), and a three-phase alternating current is used for the power supply of the motor 11. Is done. A mesh-shaped 15 is a stainless insect-proof net.

  As shown in FIG. 2, the motor 11 is housed in a cylindrical motor case 12, is fixed above the support base 13, and rotates a shaft (rotary shaft 1) that protrudes left and right corresponding to the blowing part 2. To drive. The shaft 1 is supported at both ends in the vicinity of the sounding part 2 by a ball bearing 17 fixed to a guide cover 16 that connects the motor case 12 and the sounding part 2, and is rotated at high speed by the motor 11 at 3000 RPM or more and left and right sounding. Power is transmitted to part 2 at the same time.

  As shown in FIGS. 2 and 3, the sound blowing unit 2 is formed by housing the fan rotor 3 in a sound generation guide (rotor casing 5). The pronunciation guide 5 is formed in a substantially bottomed cylindrical shape by bending an aluminum plate material or the like, and is attached to the guide cover 16 with the opening portion facing. The sound generation guide 5 is provided with a circular intake port 8 on the bottom wall located on the opposite side of the guide cover 16 and a rectangular exhaust port (wind cut window 4) with a predetermined pitch on the peripheral wall.

  The fan rotor 3 is a cast aluminum product, and is formed in a substantially cylindrical shape with a sounding blade (rotary blade 6) provided between the bottom plate 18 and the ceiling plate 19. The bottom plate 18 and the ceiling plate 19 have a disk shape having a diameter substantially equal to the inner diameter of the rotor casing 5 and are arranged in parallel to each other so as to overlap. The bottom plate 18 is provided with a through hole (not shown) through which the shaft 1 of the motor 11 is inserted, so that the bottom plate 18 and the ceiling plate 19 are nuts so that their surfaces are orthogonal to the axial direction of the shaft 1. It attaches to the shaft 1 suitably by the above. On the other hand, in the center of the ceiling plate 19, an introduction port 20 having a size substantially the same as the intake port 8 of the sound generation guide 5 is opened as a ventilation port.

  In the state where the bottom plate 18 and the like are attached to the shaft 1 as described above, a plurality of sound generating blades 6 are arranged so as to be substantially radially at a predetermined angular pitch from the periphery of the shaft 1 to form a so-called impeller. The sound generation blade 6 extends in a straight line from the periphery of the shaft 1 to the outer periphery of the bottom plate 18 and the ceiling plate 19, and along the outer periphery of the bottom plate 18 and the ceiling plate 19 from the end of the ventilation unit 6 a. The outer peripheral surface of the fan rotor 3 has a blocking portion 6b extending in a constant rotational direction, and the blocking portion 6b is formed to be approximately half the length of the gap between adjacent sound generating blades 6 and 6. A discharge port 21 is formed as a ventilation port.

  Therefore, when the shaft 1 of the motor 11 rotates, the fan rotor 3 functions as a so-called centrifugal fan and pushes air in the centrifugal direction by the sound generation blades 6, 6... Near the center of the fan rotor 3 where the air is pushed out. The outside air flows through the intake port 8 of the sound generation guide 5 and the introduction port 20 of the fan rotor 3. That is, in each blowing part 2 on both sides of the motor 11, the outside air sucked into the rotor casing 5 from the axial direction of the shaft 1 on the opposite side of the motor 11 is discharged in the direction around the axis of the shaft 1.

  When the exhaust port 21 of the fan rotor 3 and the exhaust port 4 of the rotor casing 5 overlap with each other due to the rotational position of the fan rotor 3 in the rotor casing 5, the air pushed in the centrifugal direction by the sound generation blade 6 passes through these. The air is discharged to the outside of the rotor casing 5, that is, into the outside air. On the other hand, the inlet 20 of the fan rotor 3 faces the peripheral wall of the rotor casing 5 and the exhaust 4 of the rotor casing 5 is blocked by the blocking portion 6 b of the sound generation blade 6. When this occurs, the air in the fan rotor 3, that is, in the rotor casing 5, is centrifugally compressed. Thereby, whenever the fan rotor 3 rotates and the discharge port 21 and the exhaust port 4 pass each other, the compressed air is intermittently discharged from the rotor casing 5, and the frequency of air corresponding to the number of intermittents per unit time is released. A dense wave, that is, a sound wave having a frequency corresponding to the number of intermittents per unit time is emitted.

  Further, in this embodiment, in order to obtain an efficient sound-increasing effect by superimposing sounds using a pair of sounding parts 2, each sounding part 2 has a number of exhaust ports 4 in the rotor casing 5 and a sound generation. The blades 6 are formed with different numbers. As shown in FIG. 1 to FIG. 3, a blowing section 2 (hereinafter referred to as “left blowing section 2A”) disposed on the left side of the motor 11 in FIG. Is opened and the fan rotor 3 is formed with six sound generating blades 6, 6,..., While the blowing section 2 (hereinafter referred to as “right blowing section 2B”) arranged on the right side of the motor 11 in FIG. 9), nine exhaust ports 4, 4,... Are opened in the rotor casing 5, and nine sounding blades 6, 6,. Therefore, the number of times of passing between the exhaust port 21 and the exhaust port 4 described above is set to 6: 9, that is, 2: 3, in the left blowing unit 2A and the right blowing unit 2B with respect to one rotation of the fan rotor 3. As a result, the sound generating frequencies of the left and right sounding portions 2 and 2 on the left and right sides of the motor 11 differ at a ratio of approximately 2: 3.

  Therefore, when the fan rotors 3 and 3 rotate on the left and right sides of the motor 11, two sound waves having a frequency ratio of approximately 2: 3 are simultaneously played and superimposed, and the sound pressure is increased at a predetermined period in which the phases match. Strictly speaking, since the so-called wind noise caused by the passage between the exhaust port 21 and the exhaust port 4 is a composite wave of a plurality of frequency components, it is considered that the sound pressure is increased by some superposition of the included frequency components. . Furthermore, by setting the frequency ratio to approximately 2: 3, chords are generated and a comfortable harmony can be achieved.

  In addition, in this embodiment, a phase adjustment guide 7 is provided at the intake port 8 in order to further increase the sound using the intake port 8 of the sound generation guide 5. As shown in FIGS. 1 and 2, the phase adjustment guide 7 is a so-called megaphone that gradually expands linearly from one end to the other end, specifically from the air inlet 8 outward. It is formed by being bent and welded to the pronunciation guide 5. Therefore, sound waves generated by the wind-cut window 4 of the sounding guide 5 and the blocking portion 6b of the sounding blade 6 of the fan rotor 3 or sound waves reverberated in the fan rotor 3 and the sounding guide 5 are emitted from the air inlet 8 to the outside of the sounding guide 5. In this case, the phase changes by, for example, detouring through the phase adjustment guide 7 or reflection within the phase adjustment guide 7, and superimposing with the sound wave emitted directly from the wind guide window 4 to the outside of the sound generation guide 5. The sound pressure can be further increased when

  In the above embodiment, by controlling the motor 11 with an inverter or a relay, the rotational speed of the fan rotor 3 can be varied periodically to generate a sound with good audibility. is there.

  For the purpose of confirming the relationship between the presence / absence of the phase adjustment guide 7 and the sound pressure and frequency, the external environment such as temperature and humidity is almost the same in the anechoic chamber and the capacity of the motor to be used is the same. The sound pressure was measured from the front and left and right sides of about 1 m apart for the two sirens that match those described in the above embodiment except for the presence or absence of the phase adjustment guide 7. Note that the number of the sounding blades 6 and the exhaust ports 4 is 9 on the right side of the motor 11 and 6 on the left side.

  As a result of the measurement, with the phase adjustment guide 7, the front side was 151.0 decibels, the right side was 147.0 decibels, and the left side was 143.5 decibels. On the other hand, without the phase adjustment guide 7, the front side was 144.0 decibels, the right side was 142.0 decibels, and the left side was 138.0 decibels. A slight difference between the current value of 10.1 amperes and 9.4 amperes depending on the presence or absence of the phase adjustment guide 7 is unavoidable due to the influence of the flow of the wind. By providing the guide 7, it was confirmed that the sound pressure increased including the front direction where the phase adjustment guide 7 was not arranged.

  In addition, when the frequency in the left-right direction of the siren provided with the phase adjustment guide 7 was measured, it was confirmed that the right side was 340 hertz and the left side was different from 511 hertz.

  In order to confirm the influence of the sound pressure when the number of the sound generating blades 6 and the exhaust ports 4 described above is varied between the sound blowing portions 2 and 2 formed on the left and right sides of the motor 11, the temperature and humidity in the anechoic chamber are checked. The conditions of the sounding blades 6 and the like in the left and right sounding sections 2 are the same (hereinafter referred to as “left and right identical”) different from the siren (hereinafter referred to as “the same”). The sound pressure and frequency of two sirens (referred to as “difference between right and left”) were measured. In order to reduce the influence of the load on the motor, the number of sounding blades 6 and the like was set to 8 for the same siren on the left and right, and 6 and 9 for the sirens on the left and right. Note that the test generally uses 60 Hz electricity supplied to western Japan, and the phase adjusting guide 7 described above is attached to sirens having different numbers of sounding blades 6 and the like in the left and right blowing parts 2. ing.

  When the motor capacity is 0.75 KW, the left and right same thing is 129 decibels, while the left and right difference is 131 decibels, and when the motor capacity is 1.5 kW, the left and right same thing is 131 decibels. On the other hand, the difference between left and right is 133 decibels, and when the motor capacity is 2.2 KW, the same left and right is 134 decibels, while the difference between left and right is 135 decibels and the motor capacity is 3.7 KW. The left and right ones were 136 decibels, while the left and right ones were 137 decibels. The effect of the presence or absence of the phase adjustment guide 7 is also included. From this result, the sound pressure is changed by making the numbers of the sound generation blades 6 and the exhaust ports 4 different between the sound blowing portions 2 and 2 formed on the left and right of the motor 11. It was confirmed that it would increase.

  In addition, when the frequency in the left-right direction of the above-described different sirens was measured, it was confirmed that the right side was 345 Hz and the left side was different from 520 Hz.

It is a perspective view showing the present invention. It is a figure which shows an internal structure and is the front view which fractured | ruptured the upper part suitably. It is a figure which shows a blowing part, (a) is the sectional view on the 3A-3A line of FIG. 2, (b) is the sectional view on the 3B-3B line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Sound generation part 3 Fan rotor 4 Wind cut window 5 Rotor casing 6 Rotor blade 7 Phase adjustment guide 8 Inlet

Claims (4)

A motor siren having a plurality of sounding portions with different sounding frequencies driven by a single rotating shaft. A motor siren in which each of a plurality of fan rotors that rotate synchronously is housed in a rotor casing having a different number of wind cut windows. A motor siren comprising a plurality of fan rotors each having a different number of rotating blades and rotating in synchronism with each other in a rotor casing provided with a wind cut window. A fan rotor is rotatably accommodated in the rotor casing,
A motor siren in which the rotor casing is provided with an air inlet in which a phase adjustment guide is formed and a wind cut window that is intermittently opened and closed by rotation of the fan rotor.

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