JP6005532B2 - Sound measurement model and sound measurement method - Google Patents

Description

  The present invention relates to a sound measurement model and a sound measurement method used for a model experiment of a tunnel pressure wave when a railway vehicle passes through a tunnel.

  In recent years, there has been a growing social interest mainly in a frequency band called low frequency sound of 100 Hz or less, and in particular, the influence of low frequency sound generated by high-speed traveling vehicles as the speed of railway vehicles increases and the number of trains increases. Has been increasing.

  Typical examples of low-frequency sound caused by railway vehicles are tunnel micro-pressure waves generated at the tunnel entrance when railway vehicles enter the tunnel, and low-frequency sounds outside the tunnel called light sections. However, in addition to these, there is a phenomenon called a tunnel continuous wave that is continuously emitted from the tunnel entrance when a railway vehicle travels in a tunnel.

  Compared with tunnel micro-pressure waves, tunnel continuous waves have the characteristics that they have a small emission value but a long radiation time, and also contain frequency components close to the natural frequency of joinery etc. In the case of improvement, it can be considered that a problem occurs in the environment near the tunnel.

  Also, in the light section, low-frequency sound is observed as the railway vehicle travels, and the cause of the low-frequency sound in this light section is considered to be the same phenomenon as the cause of the tunnel continuous wave. Therefore, there is a possibility that the phenomenon elucidation and reduction countermeasure method of the tunnel continuous wave can be applied as it is as the phenomenon elucidation and reduction countermeasure method of low frequency sound in the light section.

  A conventional tunnel pressure wave analysis experiment such as a tunnel micro-pressure wave is performed using a model described in Patent Document 1. The analysis experiment employs a method of measuring a pressure wave generated by launching a model body guided by a guide means composed of a piano wire by launching means and causing the model body to enter a measurement area simulating a tunnel. The tunnel pressure wave is measured by a pressure gauge attached to the measurement area or a sound pressure gauge installed near the entrance / exit of the measurement area corresponding to the tunnel entrance. The model body that has passed through the measurement region is stopped by colliding with the braking device.

  Further, in the conventional model body, as a means for generating a specific frequency, a groove-like cavity 101 is formed in the circumferential direction at the tip of the model body 100 as shown in FIG. 10, or as shown in FIG. A model body 102 including a sound source unit 103 capable of generating sound waves is known.

JP 2003-177664 A

  However, in the embodiment shown in FIG. 10, when performing an experiment at a plurality of frequencies, it is necessary to form the cavity 101 according to the frequency, and in addition to the poor experimental efficiency, it is difficult to sufficiently generate low frequency sound. Furthermore, in the form shown in FIG. 11, since the guide means 105 penetrates the speaker 104, it is necessary to specially prepare the speaker 104 provided with a through hole through which the guide means 105 can be inserted at the center. There was a problem that was large. In addition, since the model body 102 is normally stopped by making it collide with a braking device, a large impact force acts on the sound source, and the sound source such as the control unit 106 is damaged.

  Therefore, the present invention has been made in view of the above problems, and can easily change the frequency to be generated, and the sound source can be stored in the model body without using a special member. An object of the present invention is to provide a sound measurement model having durability that can sufficiently withstand the impact force even when it collides with the sound.

  The sound measurement model according to the present invention is a sound measurement model comprising: a model body that is launched by a launching means; and guide means that guides the model body into a measurement region by penetrating the model body. The model body includes a sound source unit having a sound source on an outer peripheral surface and a detachable power supply box at one end in the axial direction of the sound source unit.

  In the sound measurement model according to the present invention, it is preferable that the sound source unit includes a recess formed on an outer peripheral surface and a lid that closes the recess.

  In the sound measurement model according to the present invention, it is preferable that the lid body is provided with the sound source and driving means for driving the sound source.

  In the sound measurement model according to the present invention, the sound source section preferably includes a plurality of sound sources.

  In the sound measurement model according to the present invention, it is preferable that the power supply box is provided with dry batteries arranged at equal intervals along the outer peripheral edge in a cross section orthogonal to the longitudinal direction.

  Furthermore, the sound measurement method according to the present invention is a sound measurement method in which a model body is fired by a launching means, and the model body is guided into a measurement region by a guide means penetrating the model body. A sound source unit including a sound source that transmits a sound wave of a predetermined frequency from an outer peripheral surface, and a detachable power supply box at one end in the axial direction of the sound source unit are provided.

  In the sound measurement method according to the present invention, it is preferable that the sound source unit includes a recess formed on an outer peripheral surface and a lid that closes the recess.

  In the sound measurement method according to the present invention, it is preferable that the lid body is provided with the sound source and driving means for driving the sound source.

  In the sound measurement method according to the present invention, the sound source unit preferably includes a plurality of sound sources.

  In the sound measurement method according to the present invention, it is preferable that the power source box has dry batteries arranged at equal intervals along the outer peripheral edge in a cross section orthogonal to the longitudinal direction.

  The model for sound measurement and the sound measurement method according to the present invention include a sound source unit having a sound source on the outer peripheral surface and a power supply box that is detachable at one end in the axial direction of the sound source unit. It is possible to inexpensively create a sound measurement model that can easily change the frequency and sound pressure without forming a cavity or requiring a special speaker. Further, since the power supply box is attached to the model body and integrated, it is possible to provide durability that can sufficiently withstand a large impact force when the model body is stopped.

The block diagram of the model for sound measurement which concerns on embodiment of this invention. The front view which shows the model body which concerns on embodiment of this invention. The exploded view of the model object concerning the embodiment of the present invention. The exploded view of the sound source part concerning the embodiment of the present invention. The front view which shows the sound source part main body which concerns on embodiment of this invention. It is a figure which shows the power supply box which concerns on embodiment of this invention, (a) is a front view, (b) is a side view. The graph which shows the output waveform of the model for sound measurement which concerns on embodiment of this invention. The figure which shows the modification of the sound source part which concerns on embodiment of this invention. The figure which shows the modification of the sound source part which concerns on embodiment of this invention. The figure for demonstrating the shape of the conventional model body. The figure for demonstrating the other shape of the conventional model body.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  FIG. 1 is a configuration diagram of a sound measurement model according to an embodiment of the present invention, FIG. 2 is a front view showing a model body according to the embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. 4 is an exploded view of the sound source unit according to the embodiment of the present invention, FIG. 5 is a front view showing the sound source unit body according to the embodiment of the present invention, 6A and 6B are diagrams showing a power supply box according to an embodiment of the present invention, in which FIG. 6A is a front view, FIG. 6B is a side view, and FIG. 7 is a sound measurement model according to the embodiment of the present invention. FIG. 8 is a diagram showing a modification of the sound source unit according to the embodiment of the present invention, and FIG. 9 is a diagram showing a modification of the sound source unit according to the embodiment of the present invention. It is.

  As shown in FIG. 1, the sound measurement model 1 according to this embodiment includes a model body 20 simulating a railway vehicle launched by the launching means 10, and a measurement simulating a tunnel by penetrating the model body 20. A guide means 30 made of a wire such as a piano wire for guiding the model body 20 is provided in the region 40. The sound measurement model 1 according to the present embodiment employs a method of measuring a pressure wave generated when the model body 20 launched by the launching means 10 enters the measurement region 40, and is attached to the measurement region. The tunnel pressure wave is measured by a pressure gauge installed in the vicinity of the entrance and exit of the measurement area corresponding to the tunnel wellhead. The model body 20 that has passed through the measurement region is stopped by colliding with the braking device 50.

  The firing unit 10 includes a plurality of pairs of roller sets arranged in line symmetry with the guide unit 30. The model body 20 passes between the roller sets, and is sequentially accelerated by the plurality of roller sets. The model body 20 can be fired at a desired speed.

  The measurement region 40 has an inner diameter of about 100 mm, and the sound measurement model 1 according to this embodiment is formed at a scale of about 1/100 as a whole. It should be noted that the length of the measurement region 40 along the guide means 30 can be appropriately changed according to the experimental conditions.

  Next, the model body 20 used in the sound measurement model 1 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 2, the model body 20 has a shape imitating a railway vehicle, the top shape is a simple axisymmetric shape having a cross-sectional area change equivalent to that of the railway vehicle, and the intermediate portion has a uniform diameter. It has a circular cross section. Further, the outer peripheral surface is smoothly formed along the axial direction and the circumferential direction in order to prevent the disturbance of the airflow in the vicinity of the model body 20 at the time of measurement.

  As shown in FIG. 3, the model body 20 is configured by sequentially assembling a distal end portion 23, a sound source portion 21, and a trunk portion 24 in the axial direction. The distal end portion 23, the sound source portion 21, and the body portion 24 are screwed together by connecting means 23a and 24a. FIG. 3 shows only one end of the model body 20, and the tip portion 23 is similarly attached to the other end side.

  As shown in FIG. 4, the sound source unit 21 can drive a sound source 28 that transmits a sound wave of a predetermined frequency from the outer peripheral surface toward the radial direction of the model body 20, and can drive the sound source 28 and set it to a desired frequency. Drive means 29. The sound source 28 and the driving means 29 are accommodated in the lid body 25. As shown in FIG. 3, an opening 25a is formed in the lid 25, and sound waves are transmitted from the opening 25a. Note that the frequency to be transmitted can be appropriately set by a switch provided in the driving means 29 with the lid 25 opened.

  The opening 25a transmits a sound wave in the radial direction of the model body 20, but the sound measurement model 1 according to the present embodiment is less susceptible to directivity and the like when measuring in a low frequency region. Since stable measurement can be performed without transmitting a sound wave uniformly in the direction, it is preferably used when measuring a frequency band of 1000 Hz or less, for example.

  A power source box 22 is detachably attached to one end of the sound source unit 21 in the axial direction. A terminal 22 b protrudes from the power supply box 22, and the power of the driving unit 29 is turned on or off by connecting or releasing the terminal 22 b to or from the sound source unit 21. Thus, since the power supply of the drive means 29 is turned on / off by assembling the power supply box 22, it is not necessary to attach a separate power switch to the drive means 29, and there is no power switch, so that the model body 20 This has the advantage that it is not necessary to form unnecessary protrusions on the outer peripheral surface.

  As shown in FIGS. 4 and 5, the sound source unit 21 includes a sound source unit main body 21 a in which a guide hole 31 through which the guide means 30 is inserted is penetrated in the axial direction and a lid body 25. The body 25 is assembled so as to close the recess 26 formed on the outer peripheral surface of the sound source unit main body 21a. The lid body 25 is screwed to the sound source unit main body 21a through the fastening hole 25b. Further, a power supply storage portion 27 in which the above-described power supply box 22 is stored is formed at one end of the sound source portion main body 21a in the axial direction.

  As shown in FIG. 6A, the power supply box 22 is formed in a substantially cylindrical shape that can be stored in the power supply storage portion 27, and is guided coaxially with the guide hole 31 drilled in the sound source body 21a. A hole 32 is formed. The power supply box 22 accommodates a plurality of dry batteries 22a in the axial direction. As shown in FIG. 6B, the dry battery 22a is substantially along the outer periphery of the power supply box 22 in a cross section orthogonal to the longitudinal direction. It is arranged at equal intervals.

  Thus, by arranging the dry batteries 22a at substantially equal intervals, the weight balance of the model body 20 can be optimized, and the model body 20 can be smoothly launched and guided.

  The sound measurement model 1 according to the present embodiment described above includes a sound source unit 21 including a sound source 28 with the model body 20 facing the outer peripheral surface, and a power supply box 22 attached to one end of the sound source unit 21 in the axial direction. Are integrally formed, it is possible to transmit a desired frequency, and it is possible to provide durability enough to withstand the impact even when the brake device 50 is collided and stopped.

  Since the sound source 28 is attached to the lid body 25 and the guide means 30 is inserted into a guide hole 31 formed in the axial center portion of the sound source section main body 21a, the sound source 28 and the guide means 30 interfere with each other. In addition, since the sound source 28 can be arranged without using a special speaker, the manufacturing cost of the model body 20 can be suppressed.

[Example]
As shown in FIG. 7, the sound measurement model 1 according to the present embodiment can transmit each frequency. According to the measurement results shown in FIG. 7, distortion is generated at 300 Hz and it is difficult to apply to accurate measurement. However, at 500, 700 and 1000 Hz, the shape is almost sinusoidal. It can be seen that the present invention is sufficiently applicable to wave sound measurement. As described above, since the sound measurement model 1 according to the present embodiment is formed at a scale of about 1/100, conversion of the model scale of measurement in an actual tunnel is performed. Depending on the measurement result of the measurement model 1, it is possible to perform measurement and analysis in a low frequency band of 5 Hz to 10 Hz as a local equivalent value.

  Furthermore, as shown in the modification of the present embodiment shown in FIGS. 8 and 9, the sound source unit 21 ′ according to the modification can be configured to include a plurality of sound sources 28. By forming in this way, it is possible to sufficiently secure the volume of the sound wave transmitted from the opening 25a, so that it is possible to perform more detailed measurement and analysis of low-frequency sound.

  8 and 9, the case where three sound sources 28 and openings 25a are formed along the longitudinal direction of the lid 25 'has been described, but the number of sound sources 28 and openings 25a is not limited to this, It can be changed as appropriate.

  Moreover, although the model 1 for sound measurement which concerns on this embodiment mentioned above demonstrated the case where the cover bodies 25 and 25 'were assembled | attached to the sound source part main body 21a by screwing, the assembly method of the cover bodies 25 and 25' is demonstrated. For example, the sound source main body 21 and the lids 25 and 25 ′ may be assembled so as to be freely opened and closed by applying a hinge structure. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  1 sound measurement model, 10 launching means, 20 model body, 21, 21 'sound source part, 21a sound source part main body, 22 power supply box, 22a dry cell, 22b terminal, 23 tip part, 24 body part, 25, 25' cover body , 25a opening, 26 concave portion, 27 power supply accommodating portion, 28 sound source, 29 drive means, 30 guide means, 31, 32 guide holes, 40 measurement area, 50 braking device.

Claims (10)

A model body fired by a launching means;
In the sound measurement model comprising the guide means for guiding the model body into the measurement region by penetrating the model body,
The model body includes a sound source unit including a sound source on an outer peripheral surface;
A sound measurement model comprising a detachable power supply box at one end in the axial direction of the sound source unit. The sound measurement model according to claim 1,
The sound source unit includes a concave portion formed on an outer peripheral surface and a lid that closes the concave portion. In the sound measurement model according to claim 2,
The sound measuring model, wherein the lid is provided with the sound source and driving means for driving the sound source. In the sound measurement model according to any one of claims 1 to 3,
The sound source model includes a plurality of sound sources, and a sound measurement model. In the sound measurement model according to any one of claims 1 to 4,
The power supply box is a sound measurement model in which dry batteries are arranged at equal intervals along an outer peripheral edge in a cross section orthogonal to the longitudinal direction. Launch the model body by launching means,
In the sound measurement method for guiding the model body into the measurement region by the guide means penetrating the model body,
The model body includes a sound source unit including a sound source that transmits sound waves of a predetermined frequency from the outer peripheral surface;
A sound measuring method comprising a detachable power supply box at one end in the axial direction of the sound source unit. The sound measurement method according to claim 6,
The sound source unit includes a recess formed on an outer peripheral surface and a lid that closes the recess. The sound measurement method according to claim 7,
The sound measuring method, wherein the lid is provided with the sound source and driving means for driving the sound source. The sound measurement method according to any one of claims 6 to 8,
The sound source unit includes a plurality of sound sources. The sound measurement method according to any one of claims 6 to 9,
The power supply box has a cross section orthogonal to the longitudinal direction, and dry batteries are arranged at equal intervals along the outer peripheral edge.

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