Sound measuring device

Abstract

To provide a sound measuring device that can reduce the number of parts in a holding portion and make a sound sensor less susceptible to vibration, thereby suppressing the occurrence of measurement errors.SOLUTION: A sound measuring device 100 includes a sound sensor 110 and a holder 120 that holds the sound sensor 110 facing the inside of a horn 13a of a speaker 13. The sound sensor 110 includes a sound collection substrate S and a sensor housing 111 that incorporates the sound collection substrate S, and a portion of the sensor housing 111 abuts against the inner surface of the horn 13a, such that the sensor housing 111 is fixed to the horn 13a.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a sound measuring device. [Background technology]

[0002] A sound measuring device is known that includes a sound sensor that detects sound emitted by a speaker and a holding part that clamps and holds a portion of the opening edge side of the speaker's horn and holds the sound sensor facing inward of the horn (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-82990 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned sound measuring device, the holding part has a clamp with a U-shaped cross section and a connecting plate fixed to the clamp, and the sound sensor is attached to the connecting plate. Therefore, the number of parts that make up the holding part increases, and the sound sensor is attached away from the clamp, making it more susceptible to vibration, which may cause errors in the measurement value of sound pressure.

[0005] The present invention aims to provide a sound measuring device that can reduce the number of parts in the holding section and suppress the occurrence of measurement errors by making the sound sensor less susceptible to vibration. [Means for solving the problem]

[0006] In order to solve the above problems, the sound measuring device of the present invention comprises a sound sensor that detects sound emitted by a speaker and a holding part that holds the sound sensor facing the inside of the horn of the speaker, and the sound sensor has a sensor main body and a sensor housing that incorporates the sensor main body, and a part of the sensor housing abuts against the inner surface of the horn so that the sensor housing is fixed to the horn.

[0007] In this case, the sensor housing is provided with a first abutment portion that abuts against the horn at the rear side of the horn, and at least two second abutment portions that are located on the opening end side of the horn and abut against the horn at a distance from each other along the opening end edge of the horn, and the first abutment portion is preferably positioned at a position that is between the at least two second abutment portions when viewed from the rear side of the horn, and the sensor housing is preferably supported by the horn via the first abutment portion and the second abutment portion.

[0008] Furthermore, it is preferable that the holding portion comprises a first piece located outside the horn and a pressing member extending through the first piece and pressing against the outer surface of the horn, and that the sensor housing is fixed to the horn by the pressing force of the pressing member.

[0009] The pressing member is preferably configured by a screw member that can advance and retreat in a direction that penetrates the first arm portion. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a sound measuring device that can reduce the number of parts in the holding portion and make the sound sensor less susceptible to vibration, thereby suppressing the occurrence of measurement errors. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing an installation situation at a railroad crossing of a speaker to which a sound measuring device according to this embodiment is attached. [Figure 2]FIG. 3 is a perspective view showing an attachment state of the speaker and the sound measuring device. [Figure 3] FIG. 2 is a perspective view of the sound measuring device as seen obliquely from above. [Figure 4] FIG. 2 is a perspective view of the sound measuring device as seen from diagonally below. [Figure 5] Cross-sectional view of line AA in Figure 2 [Figure 6] BB line cross-sectional view of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. The railroad crossing 1 shown in FIG. 1 is a facility installed at various locations on a railroad line and includes a pole-shaped structure 11, a railroad crossing gate 12, a speaker 13, a railroad crossing instrument box 14, and a sound measuring device 100. The pole-shaped structure 11 is a pillar installed at the railroad crossing 1 and supports the railroad crossing gate 12 and the speaker 13. The railroad crossing gate 12 is a traffic control device that raises or lowers a barrier 12a to restrict or release the intrusion of people or vehicles onto the tracks. The speaker 13 is an alarm device that is installed at the top end of the pole-shaped structure 11 and is configured to emit an alarm sound before and after a train passes. The railroad crossing instrument box 14 is a communication device that is installed next to the pole-shaped structure 11 and collects various information related to the monitoring of the railroad crossing 1 and exchanges that information with a predetermined monitoring server. The sound measuring device 100 is a device that measures sound pressure, and measures the sound pressure of the sound emitted by the speaker 13 in order to check the functionality of the speaker 13, and transmits the measurement results wirelessly to the crossing instrument box 14. Although not shown in Figure 1, in addition to the crossing gate 12, speaker 13, and sound measuring device 100, the pillar-shaped object 11 of the crossing 1 may also support traffic lights, a display device that shows the passing status of trains, an emergency stop button device, etc.

[0013] The sound measuring device 100 includes a sound sensor 110, a holding unit 120, a control unit 130, and a relay cable 140. The sound sensor 110 is a sensor that measures the sound pressure of sound emitted by the speaker 13. The holding unit 120 holds the sound sensor 110 facing inward toward the horn 13a of the speaker 13, as described below. The control unit 130 is installed at a position below the speaker 13 on the pillar-shaped object 11, and is configured to supply power to the sound sensor 110, convert the output voltage of the sound sensor 110 into a signal representing sound pressure, and wirelessly transmit the signal to the crossing device box 14. The relay cable 140 electrically connects the sound sensor 110 and the control unit 130, and relays the power supply from the control unit 130 to the sound sensor 110 and the voltage output from the sound sensor 110 to the control unit 130. This relay cable 140 is fixed to the pillar-shaped object 11 by a predetermined fastening member 141 between the sound sensor 110 and the control unit 130. The sound measuring device 100 is roughly configured in this manner. The sound sensor 110 and the holding unit 120 in this sound measuring device 100 will be described in detail below.

[0014] Fig. 2 is a diagram showing an attachment state of the speaker 13 and the sound measuring device 100. Fig. 3 is a perspective view of the sound measuring device 100 seen obliquely from above, and Fig. 4 is a perspective view of the sound measuring device 100 seen obliquely from below. Fig. 5 is a cross-sectional view taken along line AA in Fig. 2, and Fig. 6 is a cross-sectional view taken along line BB in Fig. 2.

[0015] 2 to 6, X, Y, and Z are directions that are orthogonal to each other. In this embodiment, the left-right direction of the sound measuring device 100 is indicated by an arrow X and is referred to as the "left-right direction X." The left side of the left-right direction X is referred to as the "left side X1," and the right side is referred to as the "right side X2." The height direction of the sound measuring device 100 is indicated by an arrow Y and is referred to as the "height direction Y." One side of the height direction Y is referred to as the "sound collection side Y1," and the other is referred to as the "reception side Y2." The up-down direction of the sound measuring device 100 is indicated by an arrow Z and is referred to as the "up-down direction Z." The upper side of the up-down direction Z is referred to as the "upper side Z1," and the lower side is referred to as the "lower side Z2." Note that these directions are merely for convenience of explanation, and do not necessarily coincide with the front-rear direction, left-right direction, and up-down direction in the actual usage state of the sound measuring device 100, and do not limit the directions in the actual usage state of the sound measuring device 100.

[0016] The sound sensor 110 has a sound collection substrate S (sensor main body) accommodated and fixed inside a sensor housing 111. The sensor housing 111 is a bottomed cylindrical body with the sound collection side Y1 as its bottom 111a1, and includes a cylindrical portion 111a in which the sound collection substrate S is installed, an attachment flange 111b provided on the opening side (receiving side Y2) of the cylindrical portion 111a, a back cover 121 that closes the openings of the cylindrical portion 111a and the attachment flange 111b, and an arc-shaped eaves portion 111c that is installed along the outer peripheral surface of the cylindrical portion 111a and covers the upper side Z1 (upper side) of the sound collection substrate S. The sound sensor 110 is configured to be held by a holding portion 120 as shown in FIG. 2, with the bottom 111a1 of the cylindrical portion 111a facing the inside (sound collection side Y1) of the horn 13a. The cylindrical portion 111a is formed to extend in the height direction Y. A cap 112 is attached to the center of the bottom 111a1 of the cylindrical portion 111a. The cap 112 is a plug member that is fitted into a through-hole (not shown) that penetrates the bottom 111a1 in the plate thickness direction, and closes the through-hole from the sound collection side Y1.

[0017] The cap 112 is provided with a humidity control vent that communicates with the inside and outside of the sensor housing 111, and is configured to maintain approximately the same humidity inside and outside the sensor housing 111. A sound collection substrate S is fixed to the edge of the receiving side Y2 of the through hole into which the cap 112 is fitted, so as to face the cap 112 in the height direction Y. In other words, the sound collection substrate S is built into the sensor housing 111. The sound collection substrate S is a substrate on which a microphone element is mounted on the sound collection side Y1, and this microphone element is configured to detect sound propagated from outside the sensor housing 111. A cable connector 113 is attached to the lower side Z2 of the outer circumferential surface of the cylindrical portion 111a. This cable connector 113 is configured to be connected to the relay cable 140 described above, and an output voltage corresponding to the sound detected by the microphone element is sent to the control unit 130 via the relay cable 140.

[0018] Mounting flange 111b is a flange provided on the opening side (receiving side Y2) of cylindrical portion 111a. This mounting flange 111b has side walls 111b1 extending in the height direction Y and is formed as a hollow, thick plate that is generally rectangular when viewed from the front. Holes (or internal threads) 111b2 that penetrate in the plate thickness direction are formed at each of the four corners of the plate surface of mounting flange 111b facing the height direction Y, and mounting flange 111b is fixed to back cover 121 via these holes 111b2 with fixing members such as screws.

[0019] The back cover 121 is a member that closes the receiving side Y2 openings of the tubular portion 111a and the mounting flange 111b, and is formed in the shape of a rectangular plate. The dimension of the back cover 121 in the left-right direction X is set to be approximately the same as the dimension of the mounting flange 111b in the left-right direction X. The dimension of the back cover 121 in the up-down direction Z is set to be approximately the same as the dimension of the second piece 120b (described later) in the up-down direction Z. As described above, the opening of the sensor housing 111 is closed by fixing the mounting flange 111b to the back cover 121, and this back cover 121 functions as a lid to protect against dust after the sound collection substrate S is installed inside the sensor housing 111, and to prevent sound diffraction and transmission of sound from the receiving side Y2 of the sound collection substrate S. Female screws 121a that penetrate in the thickness direction are formed in the four corners of the plate surface of the back cover 121 facing the height direction Y, and male screw member 122 is screwed into these female screws 121a via second piece 120b.

[0020] In this embodiment, the eaves portion 111c is formed in a semicircular arc shape when viewed from the front, and is disposed on the upper side Z1 of the tubular portion 111a. The eaves portion 111c extends in the height direction Y from the plate surface of the mounting flange 111b on the sound collection side Y1 along the outer peripheral surface of the tubular portion 111a, and its dimension in the height direction Y is set to be larger than the dimension of the tubular portion 111a in the height direction Y. With this configuration, the tip of the eaves portion 111c protrudes from the bottom portion 111a1 of the tubular portion 111a toward the sound collection side Y1, and the eaves portion 111c functions as an eaves, preventing water and dust from entering the tubular portion 111a and coming into contact with the sound collection substrate S. The shape of the eaves portion 111c is not limited to a semicircular arc shape as seen from the front, as in this embodiment, but may be such that both ends in the left-right direction X continue to the lead-out portion of the cable connector 113, or may be a cylindrical shape that covers the entire outer periphery of the tubular portion 111a. In other words, the shape of the eaves portion 111c may be any eaves shape that can protect the humidity control vent of the cap 112 from rain and snow.

[0021] The eave portion 111c has side walls 111c1 at its left X1 end and right X2 end, each having an outer wall surface facing outward in the left-right direction X. As shown in Fig. 6, a dimension W1 in the left-right direction X from the outer wall surface of the side wall 111c1 at the left X1 side to the outer wall surface of the side wall 111c1 at the right X2 side is smaller than a dimension W2 in the left-right direction X from the outer wall surface of the side wall 111b1 of the mounting flange 111b facing the left X1 side to the outer wall surface facing the right X2 side. As a result, a step 114 in the left-right direction X is formed between the side wall 111b1 of the mounting flange 111b and the side wall 111c1 of the eave portion 111c.

[0022] A reinforcing rib 111c2 that protrudes toward the lower side Z2 and reinforces the eaves portion 111c is formed in the center in the left-right direction X of the wall surface of the eaves portion 111c that faces the lower side Z2. That is, the reinforcing rib 111c2 is provided on the portion of the eaves portion 111c that faces the sound collection substrate S. The reinforcing rib 111c2 reinforces the eaves portion 111c and increases its rigidity, making it less likely to vibrate. Two reinforcing ribs 111c2 are formed with a gap between them in the left-right direction X, and extend in the height direction Y from the bottom 111a1 of the tubular portion 111a to the end of the eaves portion 111c on the sound collection side Y1, as shown in FIG. Since the reinforcing rib 111c2 is provided on the underside Z2 of the eave portion 111c, the reinforcing rib 111c2 is less likely to be exposed to the outside of the eave portion 111c, which makes it less likely for water, dust, etc. to accumulate between the eave portion 111c and the reinforcing rib 111c2, or between one reinforcing rib 111c2 and the other reinforcing rib 111c2.

[0023] It is desirable that the protruding directions of one reinforcing rib 111c2 and the other reinforcing rib 111c2 are set parallel to each other and parallel to the vertical direction Z. For example, if the reinforcing ribs 111c2 are arranged so as to protrude radially, i.e., in the radial direction, from the center of the bottom 111a1 of the tubular portion 111a, the reinforcing ribs 111c2 will be inclined with respect to the vertical direction Z, and rainwater, dust, etc. may accumulate on the inclined portion. It is also desirable that the reinforcing rib 111c2 be positioned above the cap 112 in the vertical direction Z1. This configuration allows the reinforcing ribs 111c2 to function as eaves, such as to protect the humidity control vent from rain.

[0024] A portion of the sensor housing 111 configured in this manner is adapted to come into contact with the inner surface of the horn 13a when the sound measuring device 100 is fixed to the speaker 13. Specifically, as shown in Fig. 6, the outer wall surface of the side wall 111c1 on the left side X1 of the eaves portion 111c is configured so that a portion located on the sound collection side Y1 (rear side) of the horn 13a can come into contact with the inner surface of the horn 13a when the sound measuring device 100 is fixed to the speaker 13, and this portion constitutes a first abutment portion A. Furthermore, the upper side Z1 and lower side Z2 portions of the outer wall surface of the side wall 111b1 of the mounting flange 111b facing the left side X1 are located on the receiving side Y2 (front side) of the horn 13a when the sound measuring device 100 is fixed to the speaker 13, and can come into contact with the inner surface of the horn 13a, and this portion constitutes a second abutment portion B. That is, the sensor housing 111 is provided with a first abutment portion A located on the sound collection side Y1 (rear side) of the horn 13a and a second abutment portion B located on the receiving side Y2 (front side) of the horn 13a, which are capable of abutting against the inner surface of the horn 13a.

[0025] Due to the relationship between the dimensions W1 and W2 described above, the second contact portion B is located on the left side X1 (the side of the first piece 120a described below) rather than the first contact portion A. Therefore, the step 114 described above is a step such that the second contact portion B is located on the left side X1 (the side of the first piece 120a described below) rather than the first contact portion A. Furthermore, due to the positional relationship between the first contact portion A and the second contact portion B, when the sound measuring device 100 is attached to the speaker 13, as shown in FIG. 5, the sound measuring device 100 is supported on the horn 13a by three points (three ranges), namely the second contact portion B, the first contact portion A, and the second contact portion B, from the upper side Z1 to the lower side Z2 of the horn 13a. As shown in FIG. 6, the sound measuring device 100 is supported on the horn 13a by three points (three ranges) from the sound collecting side Y1 to the receiving side Y2 of the horn 13a: the first contact portion A, the tip portion 124a (tip) of the hexagonal bolt 124 (screw member) described later, and the second contact portion B.

[0026] The holding portion 120 is an integral part having an L-shaped cross section, in which a plate-like first piece 120a extending in the height direction Y and a plate-like second piece 120b extending in the left-right direction X are bent and connected. The first piece 120a is formed in a rectangular shape that is long in the up-down direction Z, and is provided so as to be located outside the horn 13a when the sound measuring device 100 is fixed to the speaker 13, as shown in FIG. 2. The plate surface of the first piece 120a facing the right side X2 faces the left side X1 portion of the sensor housing 111 in the left-right direction X. As shown in FIGS. 3 and 4, a female screw 120a1 having the same thread size as a hexagon bolt 124 (described later) is formed to penetrate the first piece 120a in the left-right direction X (plate thickness direction) at a central portion in the up-down direction Z between the first contact portion A and the second contact portion B in the height direction Y. A nut 123 having an internal thread of approximately the same diameter as the internal thread 120a1 is disposed on the edge of the internal thread 120a1 on the left side X1 in the penetration direction, and a hexagon bolt 124 is fastened to this nut 123. That is, the combination of the hexagon bolt 124, the internal thread 120a1 of the first piece 120a, and the nut 123 functions as a double nut to prevent the hexagon bolt 124 from loosening.

[0027] The hexagon bolt 124 is configured so that its tip 124a can be moved closer to or farther away from the left side X1 portion of the sensor housing 111 by adjusting the degree of tightening of the first arm 120a relative to the internal thread 120a1. The position of the internal thread 120a1 is as described above, so that when the sound measuring device 100 is fixed to the speaker 13, the tip of the hexagon bolt 124 abuts against and presses against the outer surface of the horn 13a between the first abutment portion A and the second abutment portion B, as shown in FIG. 6 . This pressure fixes the holding portion 120 to the horn 13a. The shape of the tip 124a of the hexagon bolt 124 may be formed into a so-called R-shape, such as a cap nut or a rounded tip, or may be configured with a flat surface to form a so-called flat shape. However, by configuring it to have a flat surface, it becomes possible to bring the outer periphery of tip 124a into line contact with the outer surface of horn 13a, thereby increasing the pressing force of hexagonal bolt 124, and therefore a flat shape is desirable from the viewpoint of stably maintaining the state in which sound measuring device 100 is fixed to horn 13a. After sound measuring device 100 is fixed to horn 13a, by tightening nut 123, it is possible to perform reliable fixation to horn 13a without loosening.

[0028] The second piece 120b is formed in a rectangular shape that is long in the left-right direction X, and is arranged so that its plate surface facing the sound collection side Y1 is parallel to the plate surface facing the receiving side Y2 of the mounting flange 111b. As shown in FIG. 2, this second piece 120b extends inward in the left-right direction X beyond the opening edge 13b of the horn 13a when the sound measuring device 100 is fixed to the speaker 13. A female thread (not shown) is formed in the second piece 120b at a position coaxial with the female thread 121a formed in the back cover 121, and a male screw member 122 is screwed into this female thread from the receiving side Y2. The sound sensor 110 is fixed to the holder 120 configured in this manner via the back cover 121.

[0029] In the sound measuring device 100 described above, the holding part 120 integrated with the sound sensor 110 is attached to the horn 13a of the speaker 13 by tightening the hexagon bolt 124. At this time, the sound measuring device 100 is fixed to the speaker 13 by sandwiching the horn 13a between the first piece 120a of the holding part 120 and the sensor housing 111. Specifically, a portion 13c of the opening edge 13b of the horn 13a of the speaker 13 is pressed at three points (three ranges), namely the tip end 124a of the hexagon bolt 124, the first contact portion A, and the second contact portion B, and thus the sound measuring device 100 is fixed to the speaker 13 in a state of being supported at three points. 1, the control unit 130 fixed to the pillar-shaped object 11 and the sound sensor 110 held by the holding part 120 are connected by a relay cable 140, and the relay cable 140 is fixed to the pillar-shaped object 11 by a fastening member 141. Through this series of operations, the installation of the sound measuring device 100 is completed.

[0030] According to the sound measuring device 100 of this embodiment, the holding portion 120 is formed of an integral part with an L-shaped cross section in which the first arm 120a and the second arm 120b are continuous, and the sound sensor 110 is fixed to the second arm 120b. Therefore, there is no need to use a part such as a connecting plate to attach the sound sensor 110, and the number of parts of the holding portion 120 can be reduced accordingly. The sound measuring device 100 is fixed so that a part 13c of the opening edge 13b of the horn 13a is sandwiched between the first arm 120a of the holding portion 120 and the sensor housing 111, which is fixed to the second arm 120b of the holding portion 120 and has a portion abutting against the inner surface of the horn 13a. In this way, because the sensor housing 111 constituting the sound sensor 110 directly abuts the horn 13a, it is possible to suppress the generation of vibration in the sound sensor 110 compared to a device in which the sound sensor 110 is attached away from a clamp and is therefore more susceptible to vibration. Therefore, it is possible to provide a sound measuring device 100 that can reduce the number of parts of the holding portion 120 and also make the sound sensor 110 less susceptible to vibration, thereby suppressing the occurrence of measurement errors.

[0031] Furthermore, according to this embodiment, by tightening a hexagonal bolt 124 (screw member) that penetrates first piece 120a, tip portion 124a (tip) of hexagonal bolt 124 is pressed against the outer surface of horn 13a, thereby fixing holder 120 to horn 13a. This allows sound measuring device 100 to be firmly attached to speaker 13. Sensor housing 111 is provided with a first abutment portion A located on sound collection side Y1 (rear side) of horn 13a and a second abutment portion B located on sound reception side Y2 (front side) of horn 13a, which are capable of abutting against the inner surface of horn 13a. Meanwhile, tip portion 124a of hexagonal bolt 124 that penetrates first piece 120a abuts against the outer surface of horn 13a between first abutment portion A and second abutment portion B. Therefore, the sound measuring device 100 can be supported on the horn 13a by three points (three ranges) from the sound collecting side Y1 to the receiving side Y2 of the horn 13a: the first abutment portion A, the tip portion 124a of the hex bolt 124, and the second abutment portion B, so that the sound measuring device 100 can be stably maintained fixed to the horn 13a.

[0032] Furthermore, by providing step 114 in sensor housing 111, it is possible to form first contact portion A and second contact portion B that is located closer to first arm portion 120a than first contact portion A, thereby simplifying the shape of sensor housing 111. Therefore, for example, when sensor housing 111 is molded from resin, it can be formed in a shape without undercuts, and the mold used to mold sensor housing 111 can be a simple one, such as an up-and-down mold that does not require a slide.

[0033] Moreover, the sensor housing 111 is provided with a visor portion 111c that covers the sound collection substrate S (sensor main body), and the visor portion 111c can prevent water or dust from entering the cylindrical portion 111a and coming into contact with the sound collection substrate S. Furthermore, the visor portion 111c abuts against the inner surface of the horn 13a, and the sound measuring device 100 can be fixed to the horn 13a via the visor portion 111c.

[0034] Furthermore, two reinforcing ribs 111c2 are formed at a distance in the left-right direction X on the wall surface of the eaves portion 111c facing the underside Z2, protruding toward the underside Z2 and reinforcing the eaves portion 111c. These two reinforcing ribs 111c2 reinforce the eaves portion 111c, increasing its rigidity and making the eaves portion 111c less susceptible to vibration. This reduces errors in sound pressure measurements due to vibration of the eaves portion 111c. Furthermore, because the reinforcing ribs 111c2 are provided on the portion of the eaves portion 111c facing the sound collection substrate S, the reinforcing ribs 111c2 are less likely to be exposed, preventing water, dust, and the like from accumulating between the eaves portion 111c and the reinforcing ribs 111c2, or between one reinforcing rib 111c2 and the other reinforcing rib 111c2.

[0035] Furthermore, as described above, by installing the sound measuring device 100 on the speaker 13 as an alarm at the railroad crossing 1, where there is a high demand for measuring sound pressure at any time and where they are installed in many places, it is possible to effectively utilize the effect of reducing the number of parts as described above and to configure a low-cost alarm function inspection system. Also, although the speaker 13 is prone to vibration due to vibrations from passing trains and cars, rain, wind, speaker sound, etc., the sound measuring device 100 of the present invention can make the sound sensor 110 less likely to vibrate as described above, so that it is possible to configure an alarm function inspection system by reducing resonance of the sound sensor 110 and suppressing sound pressure measurement errors.

[0036] Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also encompasses design changes and the like that do not deviate from the gist of the present invention. For example, in this embodiment, the back cover 121 that closes the opening of the sensor housing 111 is formed in a rectangular shape, and its dimension in the vertical direction Z is set to be approximately the same as the dimension in the vertical direction Z of the second arm portion 120b of the holder 120. In other words, the dimension in the vertical direction Z of the back cover 121 is set to be larger than the dimension in the vertical direction Z of the mounting flange 111b. The sensor housing 111 is fixed to the holder 120 via the back cover 121. However, the back cover 121 is not essential for supporting the sound measuring device 100 when the sound measuring device 100 is fixed to the speaker 13, and therefore the shape and size of the back cover 121 are not limited to those of this embodiment.

[0037] For example, the mounting flange 111b may be cylindrical, with a female thread provided on its inner circumferential surface, and the back cover 121 configured with a male thread on its outer circumferential surface that screws into the female thread. An example of such a back cover 121 is a screw-on cover in which the receiving side Y2 of the mounting flange 111b is flat. Alternatively, a groove may be provided on one of the inner circumferential surface of the mounting flange 111b or the outer circumferential surface of the back cover 121, and a rib that fits into the groove may be provided on the other, so that the opening of the sensor housing 111 is closed with a cap-like back cover 121 that is fixed by the engagement of the groove and rib.

[0038] Furthermore, it is also possible to omit the back cover 121 itself and fix the mounting flange 111b directly to the second piece 120b. However, the sound measuring device 100 fixed to the speaker 13 as an alarm for the railroad crossing 1 may be disassembled at the site where the railroad crossing 1 is installed by separating the sensor housing 111 and the holding part 120 for reasons such as changing the pull-out direction of the cable connector 113 (downward Z2 in this embodiment). In this case, in a configuration in which the back cover 121 is omitted, the inside of the sensor housing 111 communicates with the outside through the opening, and there is a risk that water or dust may come into contact with the microphone element of the sound collection substrate S. Therefore, it is desirable to provide the back cover 121 as a dustproof measure for the inside of the sensor housing 111. [Explanation of symbols]

[0039] S Sound collection board (sensor body) 100 Sound measuring device 13 Speaker 13a Horn 13b Opening edge 13c Part (Part) 110 Sound Sensor 111 Sensor housing 120 Holding part 120a First piece 120b Second piece

Claims

1. a sound sensor that detects the sound emitted by the speaker; a holding portion that holds the sound sensor facing the inside of the horn of the speaker, The sound sensor includes a sensor body and a sensor housing that houses the sensor body. A sound measuring device, characterized in that the sensor housing is fixed to the horn with a portion of the sensor housing abutting against the inner surface of the horn.

2. The sensor housing is provided with a first contact portion that contacts the horn at a rear side of the horn, and at least two second contact portions that are located on an open end side of the horn and are spaced apart from each other along an open end edge of the horn and contact the horn, the first contact portion is disposed at a position between at least two of the second contact portions when viewed from the back side of the horn, 2. The sound measuring device according to claim 1, wherein the sensor housing is supported by the horn via the first contact portion and the second contact portion.

3. the holding portion includes a first piece located outside the horn, and a pressing member extending through the first piece and pressing against an outer surface of the horn, 3. The sound measuring device according to claim 1, wherein the sensor housing is fixed to the horn by the pressing force of the pressing member.

4. 4. The sound measuring device according to claim 3, wherein the pressing member is configured by a screw member that can advance and retreat in a direction penetrating the first piece portion.

Images