JP7704671B2 - Sound pressure measuring device - Google Patents

Description

The present invention relates to a sound pressure measuring device.

A sound pressure measuring device is known that includes a sound pressure sensor that measures the sound pressure of the 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 pressure sensor facing inward of the horn (see, for example, Patent Document 1).

JP 2021-82990 A

In the above-mentioned sound pressure 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 pressure sensor is attached to the connecting plate. This increases the number of parts that make up the holding part, and the sound pressure sensor is easily vibrated because it is attached away from the clamp, which may cause errors in the sound pressure measurement.

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

In order to solve the above problems, the sound pressure measuring device of the present invention comprises a sound pressure sensor that measures the sound pressure of sound emitted by a speaker, and a holding part that holds the sound pressure sensor toward the inside of the horn of the speaker, the holding part being composed of an integral part with an L-shaped cross section in which a first piece and a second piece are bent and connected, the first piece being positioned on the outside of the horn, and the second piece being provided extending inward beyond the opening edge of the horn, the sound pressure sensor having a sensor body and a sensor housing that incorporates the sensor body, the sensor housing being fixed to the second piece, the sensor housing being fixed to the first piece so as to sandwich a part of the horn, and a part of the sensor housing being abutted against the inner surface of the horn.

According to the present invention, the holding part is composed of an integral part with an L-shaped cross section in which the first and second pieces are continuous, and the sound pressure sensor is fixed to the second piece. Therefore, it is not necessary to use a part such as a connecting plate to attach the sound pressure sensor, and the number of parts of the holding part can be reduced accordingly. The sound pressure measuring device is fixed so that a part of the horn is sandwiched between the first piece of the holding part and the sensor housing fixed to the second piece of the holding part and a part of which abuts against the inner surface of the horn. In this way, since the sensor housing constituting the sound pressure sensor abuts directly against the horn, the occurrence of vibration in the sound pressure sensor can be suppressed compared to a device configured such that the sound pressure sensor is attached away from the clamp and is therefore more likely to vibrate. Therefore, it is possible to provide a sound pressure measuring device that can reduce the number of parts of the holding part and suppress the occurrence of measurement errors by making the sound pressure sensor less susceptible to vibration.

In addition, in this case, it is preferable that the holding portion has a screw member that penetrates the first piece, and is fixed to the horn by tightening the screw member and pressing its tip against the outer surface of the horn. With this configuration, the tip of the screw member that penetrates the first piece can be pressed against the outer surface of the horn by tightening the screw member that penetrates the first piece, and the holding portion can be fixed to the horn. This allows the sound pressure measuring device to be firmly attached to the speaker.

The sensor housing is preferably provided with a first contact portion located at the rear side of the horn and a second contact portion located at the front side of the horn that can contact the inner surface of the horn, and the tip of the screw member contacts the outer surface of the horn between the first contact portion and the second contact portion. With this configuration, the sound pressure measuring device can be supported on the horn from the rear side to the front side of the horn by three points (three ranges) - the first contact portion, the tip of the screw member, and the second contact portion - so that the sound pressure measuring device can be stably maintained fixed to the horn.

It is also preferable that the sensor housing has a step such that the second contact portion is located closer to the first arm than the first contact portion. With this configuration, by providing a step in the sensor housing, it is possible to configure a first contact portion and a second contact portion located closer to the first arm than the first contact portion, so that the sensor housing can have a simple shape.

It is also preferable that the sensor housing has a visor that covers the sensor body, and that the visor abuts against the inner surface of the horn. With this configuration, the sensor housing is provided with a visor that covers the sensor body, and the visor can prevent water and dust from coming into contact with the sensor body. Furthermore, since the visor abuts against the inner surface of the horn, the sound pressure measuring device can be fixed to the horn via the visor.

In addition, it is preferable that a reinforcing rib is provided on the portion of the eaves portion facing the sensor body side to reinforce the eaves portion. With this configuration, the reinforcing rib reinforces the eaves portion and increases its rigidity, making it difficult for the eaves portion to vibrate. This makes it possible to suppress errors in the sound pressure measurement caused by the vibration of the eaves portion. In addition, since the reinforcing rib is provided on the portion of the eaves portion facing the sensor body side, the reinforcing rib is unlikely to be exposed, which makes it possible to prevent water, dust, etc. from accumulating between the eaves portion and the reinforcing rib.

It is also preferable that the speaker is an alarm installed at a railway crossing. With this configuration, by installing the sound pressure measuring device on speakers as railway crossing alarms, which are installed in many locations and have a high demand for sound pressure measurement at any time, it is possible to effectively utilize the effect of reducing the number of parts mentioned above and configure an alarm function inspection system at low cost. Furthermore, speakers as railway crossing alarms are prone to vibration due to vibrations caused by passing trains and cars, rain, wind, speaker sounds, etc., but the sound pressure measuring device of the present invention can make it difficult for the sound pressure sensor to vibrate as described above, thereby reducing resonance of the sound pressure sensor and suppressing sound pressure measurement errors, thereby configuring an alarm function inspection system.

The present invention provides a sound pressure measuring device that can reduce the number of parts in the holding section and suppress the occurrence of measurement errors by making the sound pressure sensor less susceptible to vibration.

1 is a diagram showing an installation situation at a railroad crossing of a speaker to which a sound pressure measuring device according to an embodiment of the present invention is attached. FIG. 2 is a perspective view showing an attachment state of the speaker and the sound pressure measuring device. FIG. 2 is a perspective view of the sound pressure measuring device as viewed obliquely from above. FIG. 2 is a perspective view of the sound pressure measuring device as viewed obliquely from below. 2 is a cross-sectional view taken along line AA in FIG. 3 is a cross-sectional view taken along line BB in FIG. 2 .

The following describes an embodiment of the present invention with reference to Figures 1 to 6. The crossing 1 shown in Figure 1 is a facility installed at various locations on a railway line, and includes a pillar 11, a crossing gate 12, a speaker 13, a crossing tool box 14, and a sound pressure measuring device 100. The pillar 11 is a pillar installed at the crossing 1, and supports the crossing gate 12 and the speaker 13. The crossing gate 12 is a traffic control device that switches between restricting the intrusion of people and vehicles onto the tracks and releasing the restriction by raising or lowering the barrier 12a. The speaker 13 is an alarm device that is installed on the upper end side of the pillar 11 and is configured to emit an alarm sound before and after a train passes. The crossing tool box 14 is a communication device that is installed next to the pillar 11 and collects various information related to the monitoring of the crossing 1 and exchanges information with a specified monitoring server. The sound pressure measuring device 100 is a device that measures sound pressure, measures the sound pressure of the sound emitted by the speaker 13 to check the functionality of the speaker 13, and wirelessly transmits the measurement results to the crossing equipment box 14. Although not shown in FIG. 1, in addition to the crossing gate 12, the speaker 13, and the sound pressure measuring device 100, the pillar 11 of the crossing 1 may also support traffic signals, a display device that displays the passing status of trains, an emergency stop button device, and the like.

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

Figure 2 is a diagram showing the mounting state of the speaker 13 and the sound pressure measuring device 100. Figure 3 is a perspective view of the sound pressure measuring device 100 seen diagonally from above, and Figure 4 is a perspective view of the sound pressure measuring device 100 seen diagonally from below. Figure 5 is a cross-sectional view taken along line A-A in Figure 2, and Figure 6 is a cross-sectional view taken along line B-B in Figure 2.

2 to 6, X, Y, and Z are orthogonal directions. In this embodiment, the left-right direction of the sound pressure measuring device 100 is indicated by 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 pressure measuring device 100 is indicated by 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 "receiving side Y2". The up-down direction of the sound pressure measuring device 100 is indicated by 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 the convenience of explanation, and do not necessarily correspond to the front-back, left-right, and up-down directions when the sound pressure measuring device 100 is actually used, and do not limit the directions when the sound pressure measuring device 100 is actually used.

The sound pressure sensor 110 is a sensor housing 111 in which a sound collection substrate S (sensor body) is accommodated and fixed. The sensor housing 111 is a bottomed cylindrical shape with the sound collection side Y1 as the 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 circumferential surface of the cylindrical portion 111a and covers the upper side Z1 (upper side) of the sound collection substrate S. This sound pressure sensor 110 is configured to be held by the 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 tube 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.

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 keep the humidity inside and outside the sensor housing 111 approximately the same. 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. That is, 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 the outside of the sensor housing 111. A cable connector 113 is attached to the lower side Z2 part of the outer circumferential surface of the tube portion 111a. This cable connector 113 is provided to be connected to the above-mentioned relay cable 140, 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.

The mounting flange 111b is a flange provided on the opening side (receiving side Y2) of the tube portion 111a. The mounting flange 111b has a side wall 111b1 extending in the height direction Y and is formed as a hollow thick plate that is generally rectangular when viewed from the front. At the four corners of the plate surface facing the height direction Y of the mounting flange 111b, holes (or female threads) 111b2 that penetrate in the plate thickness direction are formed, and the mounting flange 111b is fixed to the back cover 121 through these holes 111b2 by a fixing member such as a screw.

The back cover 121 is a member that closes the openings of the receiving side Y2 of the tube portion 111a and the mounting flange 111b, and is formed in a rectangular plate shape. 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, which will be 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, so this back cover 121 functions as a lid for preventing dust after the sound collection substrate S is installed inside the sensor housing 111 and for preventing sound diffraction and transmission of sound from the receiving side Y2 of the sound collection substrate S. Female screws 121a that penetrate in the plate thickness direction are formed in the four corners of the plate surface facing the height direction Y of the back cover 121, and a male screw member 122 is screwed into the female screws 121a via the second piece 120b.

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

At the left X1 end and right X2 end of the eaves portion 111c, a sidewall 111c1 with an outer wall surface facing outward in the left-right direction X is formed. As shown in FIG. 6, the dimension W1 in the left-right direction X from the outer wall surface of the sidewall 111c1 on the left X1 to the outer wall surface of the sidewall 111c1 on the right X2 is smaller than the dimension W2 in the left-right direction X from the outer wall surface of the sidewall 111b1 of the mounting flange 111b facing the left X1 to the outer wall surface facing the right X2. As a result, a step 114 in the left-right direction X is formed between the sidewall 111b1 of the mounting flange 111b and the sidewall 111c1 of the eaves portion 111c.

A reinforcing rib 111c2 that protrudes toward the lower side Z2 and reinforces the eaves portion 111c is formed in the center of the left-right direction X of the wall surface facing the lower side Z2 of the eaves portion 111c. That is, the reinforcing rib 111c2 is provided on the part of the eaves portion 111c facing the sound collection substrate S. The reinforcing rib 111c2 reinforces the eaves portion 111c and increases its rigidity to make the eaves portion 111c 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 tube 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 lower side Z2 of the eaves portion 111c, the reinforcing rib 111c2 is less likely to be exposed to the outside of the eaves portion 111c, which makes it less likely for water, dust, etc. to accumulate between the eaves portion 111c and the reinforcing rib 111c2, or between one reinforcing rib 111c2 and the other reinforcing rib 111c2.

The protruding directions of the one reinforcing rib 111c2 and the other reinforcing rib 111c2 are preferably set to be parallel to each other and to be parallel to the vertical direction Z. For example, if the reinforcing rib 111c2 is arranged to protrude radially, i.e., in the radial direction, from the center of the bottom 111a1 of the tube portion 111a, the reinforcing rib 111c2 will be inclined in the vertical direction Z, and rainwater, dust, etc. may accumulate on the inclined portion. Also, it is more preferable to install the reinforcing rib 111c2 so that it is on the upper side Z1 in the vertical direction Z than the above-mentioned cap 112. This is because, with such a configuration, the reinforcing rib 111c2 can also function as a awning, such as a rain cover for the above-mentioned humidity control vent.

A part of the sensor housing 111 configured in this manner is adapted to abut against the inner surface of the horn 13a when the sound pressure 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 adapted so that the part located on the sound collection side Y1 (rear side) of the horn 13a can abut against the inner surface of the horn 13a when the sound pressure measuring device 100 is fixed to the speaker 13, and this part constitutes the first abutment part A. In addition, the upper side Z1 and lower side Z2 parts of the outer wall surface facing the left side X1 of the side wall 111b1 of the mounting flange 111b are adapted to abut against the inner surface of the horn 13a when the sound pressure measuring device 100 is fixed to the speaker 13, and are adapted to abut against the inner surface of the horn 13a when the sound pressure measuring device 100 is fixed to the speaker 13, and this part constitutes the second abutment part B. That is, the sensor housing 111 is provided with a first contact portion A located on the sound collection side Y1 (rear side) of the horn 13a and a second contact portion B located on the receiving side Y2 (front side) of the horn 13a, which can contact the inner surface of the horn 13a.

Note that, due to the relationship between the above-mentioned dimensions W1 and W2, the second abutment portion B is located on the left side X1 (the side of the first piece 120a described below) rather than the first abutment portion A. Therefore, the above-mentioned step 114 is a step such that the second abutment portion B is located on the left side X1 (the side of the first piece 120a described below) rather than the first abutment portion A. Also, due to the above-mentioned positional relationship between the first abutment portion A and the second abutment portion B, when the sound pressure measuring device 100 is attached to the speaker 13, as shown in FIG. 5, the sound pressure measuring device 100 is supported on the horn 13a by three points (three ranges), namely the second abutment portion B, the first abutment portion A, and the second abutment portion B, from the upper side Z1 to the lower side Z2 of the horn 13a. As shown in FIG. 6, the sound pressure 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.

The holding portion 120 is an integral part having an L-shaped cross section, in which a plate-shaped first piece 120a extending in the height direction Y and a plate-shaped 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 vertical direction Z, and is arranged so as to be located outside the horn 13a when the sound pressure 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 part of the sensor housing 111 in the left-right direction X. A female screw 120a1 having the same thread size as a hexagonal bolt 124 described later is formed between the first abutment part A and the second abutment part B in the height direction Y in the vertical direction Z center of the first piece 120a, as shown in FIG. 3 and FIG. 4. A nut 123 with a female thread of approximately the same diameter as the female thread 120a1 is disposed on the edge of the female thread 120a1 on the left side X1 in the penetration direction, and a hexagonal bolt 124 is fastened to this nut 123. In other words, the combination of the hexagonal bolt 124, the female thread 120a1 of the first piece 120a, and the nut 123 functions as a double nut to prevent the hexagonal bolt 124 from loosening.

The hexagonal bolt 124 is configured so that its tip 124a can be moved closer to or farther from the left X1 portion of the sensor housing 111 by adjusting the degree of tightening of the female thread 120a1 of the first piece 120a. The position of the female thread 120a1 is as described above, so that when the sound pressure measuring device 100 is fixed to the speaker 13, as shown in FIG. 6, the tip of the hexagonal bolt 124 abuts against the outer surface of the horn 13a between the first abutment portion A and the second abutment portion B and presses against the outer surface. This pressure fixes the holding portion 120 to the horn 13a. The shape of the tip 124a of the hexagonal bolt 124 may be formed into a so-called R shape such as a cap nut or a round tip, or may be configured to have a flat surface to form a so-called flat shape. However, by configuring it to have a flat surface, it is possible to make the outer periphery of tip 124a in line contact with the outer surface of horn 13a, and the pressing force of hexagonal bolt 124 can be increased, so from the viewpoint of stably maintaining the state in which sound pressure measuring device 100 is fixed to horn 13a, a flat shape is desirable. Then, after fixing sound pressure measuring device 100 to horn 13a, by tightening nut 123, it is possible to fix it securely to horn 13a without loosening.

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 pressure measuring device 100 is fixed to the speaker 13. A female screw (not shown) is formed in the second piece 120b at a position coaxial with the female screw 121a formed in the back cover 121, and a male screw member 122 is screwed into this female screw from the receiving side Y2. The sound pressure sensor 110 is fixed to the holding part 120 configured in this manner via the back cover 121.

In the sound pressure measuring device 100 described above, the holding part 120 integrated with the sound pressure sensor 110 is attached to the horn 13a of the speaker 13 by tightening the hexagonal bolt 124. At this time, the sound pressure 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) of the tip 124a of the hexagonal bolt 124, the first abutment part A, and the second abutment part B, thereby fixing the sound pressure measuring device 100 to the speaker 13 in a state of being supported at three points. Then, as shown in FIG. 1, the control unit 130 fixed to the pillar 11 and the sound pressure 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 11 by a fastening member 141. This series of operations completes the installation of the sound pressure measuring device 100.

According to the sound pressure measuring device 100 of this embodiment, the holding part 120 is composed of an integral part with an L-shaped cross section in which the first piece 120a and the second piece 120b are continuous, and the sound pressure sensor 110 is fixed to the second piece 120b. Therefore, it is not necessary to use a part such as a connecting plate to attach the sound pressure sensor 110, and the number of parts of the holding part 120 can be reduced accordingly. The sound pressure measuring device 100 is fixed by sandwiching a part 13c of the opening edge 13b of the horn 13a between the first piece 120a of the holding part 120 and the sensor housing 111 fixed to the second piece 120b of the holding part 120 and a part of which abuts against the inner surface of the horn 13a. In this way, because the sensor housing 111 that constitutes the sound pressure sensor 110 is in direct contact with the horn 13a, the occurrence of vibration in the sound pressure sensor 110 can be suppressed compared to a device in which the sound pressure sensor 110 is attached away from the clamp and is therefore more susceptible to vibration. Therefore, it is possible to provide a sound pressure measuring device 100 that can reduce the number of parts in the holding portion 120 and suppress the occurrence of measurement errors by making the sound pressure sensor 110 less susceptible to vibration.

In addition, according to this embodiment, by tightening the hexagonal bolt 124 (screw member) that penetrates the first piece 120a, the tip 124a (tip) of the hexagonal bolt 124 can be pressed against the outer surface of the horn 13a, and the holding part 120 can be fixed to the horn 13a. Therefore, the sound pressure measuring device 100 can be firmly attached to the speaker 13. In addition, the sensor housing 111 is provided with a first abutment part A located on the sound collection side Y1 (rear side) of the horn 13a and a second abutment part B located on the receiving side Y2 (front side) of the horn 13a, which can abut against the inner surface of the horn 13a. On the other hand, the tip 124a of the hexagonal bolt 124 that penetrates the first piece 120a abuts against the outer surface of the horn 13a between the first abutment part A and the second abutment part B. Therefore, the sound pressure 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 contact part A, the tip part 124a of the hexagonal bolt 124, and the second contact part B, so that the sound pressure measuring device 100 can be stably maintained fixed to the horn 13a.

In addition, by providing the step 114 in the sensor housing 111, a first abutment portion A and a second abutment portion B that is located closer to the first piece 120a than the first abutment portion A can be formed, allowing the sensor housing 111 to have a simple shape. Therefore, for example, when the sensor housing 111 is molded from resin, it can be formed in a shape without undercuts, and the mold used to mold the sensor housing 111 can be a simple one, such as an up-down mold that does not require sliding.

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

In addition, at the center of the left-right direction X of the wall surface facing the lower side Z2 of the eaves portion 111c, two reinforcing ribs 111c2 that protrude toward the lower side Z2 and reinforce the eaves portion 111c are formed at a distance in the left-right direction X. Therefore, the two reinforcing ribs 111c2 reinforce the eaves portion 111c and increase its rigidity, making it difficult for the eaves portion 111c to vibrate. Therefore, it is possible to suppress errors in the measurement value of the sound pressure caused by the vibration of the eaves portion 111c. In addition, since the reinforcing rib 111c2 is provided on the part of the eaves portion 111c facing the sound collection substrate S side, the reinforcing rib 111c2 is difficult to be exposed, and it is possible to prevent water, dust, etc. from accumulating between the eaves portion 111c and the reinforcing rib 111c2, or between one reinforcing rib 111c2 and the other reinforcing rib 111c2.

Furthermore, as described above, by installing the sound pressure measuring device 100 on the speaker 13 as an alarm at railroad crossings 1, where there is high demand for measuring sound pressure at any time and where many locations are installed, the effect of reducing the number of parts as described above can be effectively utilized, making it possible to configure an alarm function inspection system at low cost. Also, while the speaker 13 is prone to vibration due to vibrations caused by passing trains and cars, rain, wind, speaker sound, etc., as described above, the sound pressure measuring device 100 of the present invention can make it difficult for the sound pressure sensor 110 to vibrate, thereby reducing resonance of the sound pressure sensor 110 and suppressing sound pressure measurement errors, making it possible to configure an alarm function inspection system.

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 includes design changes and the like within the scope 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 vertical dimension in the Z direction is set to be approximately the same as the vertical dimension in the Z direction of the second piece 120b of the holding part 120. In other words, the vertical dimension in the Z direction of the back cover 121 is set to be larger than the vertical dimension in the Z direction of the mounting flange 111b. Then, the sensor housing 111 is fixed to the holding part 120 via the back cover 121. However, the back cover 121 is not essential as a support function for supporting the sound pressure measuring device 100 when the sound pressure measuring device 100 is fixed to the speaker 13, so the shape and size of the back cover 121 are not limited to those of this embodiment.

For example, the mounting flange 111b may be formed cylindrically, with a female thread provided on its inner circumferential surface, and the back cover 121 may be configured to have 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 and the outer circumferential surface of the back cover 121, and a rib that fits into the groove may be provided on the other, and the opening of the sensor housing 111 may be closed with a cap-shaped back cover 121 that is fixed by the engagement of the groove and the rib.

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 pressure measuring device 100 fixed to the speaker 13 as an alarm for the railroad crossing 1 may be disassembled by separating the sensor housing 111 and the holding part 120 at the site where the railroad crossing 1 is installed for reasons such as changing the pull-out direction of the cable connector 113 (in this embodiment, the lower side Z2). 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 of water or dust coming into contact with the microphone element of the sound collection substrate S. Therefore, it is desirable to provide the back cover 121 as a dust-proof measure for the inside of the sensor housing 111.

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

Claims (7)

A sound pressure sensor that measures the sound pressure of the sound emitted by the speaker;
a holder that holds the sound pressure sensor facing an inner side of a horn of the speaker,
the holding portion is configured as an integral part having an L-shaped cross section in which a first piece and a second piece are bent and connected, the first piece being positioned outside the horn, and the second piece being provided extending inward beyond an opening edge of the horn,
The sound pressure sensor includes a sensor body and a sensor housing that houses the sensor body, the sensor housing being fixed to the second piece,
A sound pressure measuring device characterized in that the sensor housing and the first piece are fixed so as to sandwich a portion of the horn, and a portion of the sensor housing abuts against an inner surface of the horn. The sound pressure measuring device according to claim 1, characterized in that the holding part has a screw member that penetrates the first piece, and is fixed to the horn by tightening the screw member and pressing its tip against the outer surface of the horn. The sensor housing has a first contact portion located on a rear side of the horn and a second contact portion located on a front side of the horn, the first contact portion being capable of contacting an inner surface of the horn,
3. The sound pressure measuring device according to claim 2, wherein a tip of the screw member abuts against an outer surface of the horn between the first abutment portion and the second abutment portion. The sound pressure measuring device according to claim 3, characterized in that the sensor housing has a step such that the second contact portion is located closer to the first piece than the first contact portion. The sound pressure measuring device according to any one of claims 1 to 4, characterized in that the sensor housing has a visor that covers the sensor body, and the visor abuts against the inner surface of the horn. The sound pressure measuring device according to claim 5, characterized in that a reinforcing rib that reinforces the eaves is provided on the portion of the eaves that faces the sensor body. The sound pressure measuring device according to any one of claims 1 to 6, characterized in that the speaker is an alarm installed at a railway crossing.

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