JP7569694B2 - Background noise generator - Google Patents

Description

The present invention relates to a background noise generating device that generates background noise indoors in response to everyday sounds from outside.

In recent apartment buildings and other shared housing, the level of sound entering the building from outside has been reduced due to high insulation and airtightness, and in residential areas, the A-weighted sound pressure level inside the building at night can reach the low 20 dB range.
In this way, in an environment where the level of sound entering the building from outside is low, the problem arises that the sounds of daily life from outside can be heard and become bothersome inside the building. Note that "sounds of daily life from outside" refers to sounds of daily life from upper floors or neighboring residences in an apartment building, sounds of daily life from neighboring houses in a detached building, etc.
A method is known in which a resistance device is installed inside an air intake hole formed in the exterior wall of a building, and background noise (overall noise other than the target noise that occurs in the surrounding environment of the target noise) is generated to increase the volume of sound that flows into the room through the air intake hole, thereby creating an indoor environment in which it is difficult to hear everyday sounds from outside (see Patent Document 1, etc.).

JP 2018-136091 A

However, the above-mentioned method involves generating background noise by installing a resistor inside an air intake hole formed in the exterior wall of a building, and therefore has the problem that it cannot be used in rooms that do not have an air intake hole facing the exterior wall.
To provide a background noise generating device that can realize an indoor environment in which living sounds from outside are difficult to hear, even in a room that does not have an air intake opening facing an exterior wall.

The background noise generating device according to the present invention comprises an air supply hole provided in a ceiling, floor or partition wall of a room for supplying air to the room from the space above the ceiling, the space under the floor or the space within the wall, and a resistance device which provides resistance when the air passes inside the air supply hole, the air supply hole having one end opening which communicates with the room via a through hole formed in a ceiling board which forms the ceiling, or a through hole formed in a floor board which forms the floor, or a through hole formed in a wall board which forms the partition wall, and having the other end opening which is formed by a tubular part provided so as to communicate with a duct which takes in air from outside the building, the tubular part which forms the air supply hole has a diameter dimension on the other end opening side which is connected to the duct smaller than the diameter dimension on the one end opening side , the tubular part which forms the air supply hole has a one end opening side cylindrical part formed by a cylindrical part, an other end opening side cylindrical part formed by a cylindrical part having a diameter smaller than the diameter of the one end opening side cylindrical part, and a resistance device which provides resistance when the air passes inside the air supply hole, the resistance device is constructed of a cylindrical part having a blocking plate that blocks the gap between the one-end opening edge of the cylindrical part and the one-end opening edge of the part, and the resistance device is installed inside the one-end opening side cylindrical part and includes a cylindrical body formed with an outer diameter dimension corresponding to the inner diameter dimension of the one-end opening side cylindrical part and installed inside the one-end opening side cylindrical part, a circular resistance plate provided on the one-end opening side of the cylindrical body, and a cross-shaped resistance plate provided on the other-end opening side of the cylindrical body, the cross-shaped resistance plate being positioned inside the other-end opening side of the one-end opening side cylindrical part of the cylindrical part, and the circular resistance plate being positioned inside the one-end opening side of the one-end opening side of the cylindrical part of the cylindrical part, and the cross-shaped resistance plate is a cross-shaped plate with a slit formed on the inside of the cross-shaped plate having a diameter dimension corresponding to that of the cylinder, and includes a central plate portion located at the intersection of the cross, and four plate portions extending in all directions from the central plate portion and connected to the other-end opening side of the cylinder, and the slits are formed in the center of each plate portion along the extension direction of each plate portion .
According to the background noise generating device, the wind that flows into the air intake through the duct passes through the resistance device, so that the volume of the sound when the air flows into the room through the air intake increases, and an indoor environment in which it is difficult to hear everyday sounds from outside can be realized even in a room that does not have an air intake facing an exterior wall. In addition, the cylindrical part that forms the air intake has a smaller diameter at the other end opening connected to the duct than at the one end opening, so that a duct with a small diameter corresponding to the diameter at the other end opening of the cylindrical part can be used as a duct for taking in air from outside the building. This makes it possible to design the ceiling space, underfloor space, or wall space through which the duct passes as narrow as possible, and to design the indoor space as wide as possible. In addition, the speed of the air (wind) that has passed through a duct with a small diameter can be reduced at the one end opening of the cylindrical part and sent to the room.
In other words, the indoor space can be designed to be spacious, an indoor environment can be created in which it is difficult to hear everyday sounds from outside even in a room that does not have an air intake facing the exterior wall, and the speed of air (wind) that passes through a duct with a small diameter can be slowed down before being sent to the room.
In addition , with this background noise generating device, the wind that flows into the air intake through the duct passes through the cross-shaped resistance plate and the circular resistance plate, increasing the volume of the sound when the air flows into the room through the cylindrical part that forms the air intake, making it possible to create an indoor environment in which it is difficult to hear everyday sounds from outside, even in a room that does not have an air intake facing the exterior wall.
In addition , with this background noise generating device, when the wind flows into the cylindrical part through the duct and passes through the cross-shaped resistance plate and the circular resistance plate, the wind collides with the central plate portion of the cross-shaped resistance plate, increasing the volume of the sound as the air flows into the room through the cylindrical part that forms the air intake hole, thereby realizing an indoor environment in which it is difficult to hear everyday sounds from outside, even in a room that does not have an air intake hole facing the exterior wall.
The circular resistance plate is formed based on a circular plate whose diameter corresponds to that of the cylinder, and four portions of the outer periphery of the circular plate, spaced 90° from one another with respect to the center of the circular plate as a reference, are connected to one end opening of the cylinder, and the outer periphery of the circular plate is removed along the outer periphery to form a circular plate formed on the circular outer periphery, and the four portions spaced 90° from one another with respect to the center of the circular plate as a reference are left as four plate portions extending from the connection portions toward the center of the circular plate, and an arc-shaped slit centered on the center of the circular plate is formed in the arc-shaped plate portion between the plate portions adjacent to each other in the circumferential direction, and an outermost slit is formed by the space between the circular outer periphery and the inner periphery of the cylinder.
According to this background noise generating device, when the wind that flows into the cylindrical part through the duct passes through the cross-shaped resistance plate and the circular resistance plate, the air (wind) collides with the central plate portion of the cross-shaped resistance plate, then passes between each plate portion and the slits of the cross-shaped resistance plate, and collides with the wall portion in the center of the circular resistance plate or passes through the slits in the circular resistance plate, thereby increasing the volume of the sound when the air flows into the room through the cylindrical part that forms the air intake hole, and it is possible to realize an indoor environment in which it is difficult to hear living sounds from outside, even in a room that does not have an air intake hole facing the exterior wall.
The circular resistance plate is formed based on a circular plate whose diameter corresponds to that of the cylinder, a circular hole is formed in the center of the circular plate, four portions of the outer periphery of the circular plate spaced 90° from one another with respect to the center of the circular plate as a reference are connected to one end opening side of the cylinder, and the outer periphery of the circular plate is removed along the outer periphery to form a circular plate formed on the circular outer periphery, and the four portions spaced 90° from one another with respect to the center of the circular plate as a reference are left as four plate portions extending toward the center of the circular plate, an arc-shaped slit centered on the center of the circular plate is formed in the arc-shaped plate portion between the plate portions adjacent to each other in the circumferential direction, and an outermost periphery slit is formed by the space between the circular outer periphery and the inner periphery of the cylinder.
According to this background noise generating device, when the wind that flows into the cylindrical part through the duct passes through the cross-shaped resistance plate and the circular resistance plate, the air (wind) collides with the central plate portion of the cross-shaped resistance plate, then passes between each plate portion and the slits of the cross-shaped resistance plate, and then passes through the circular holes and slits of the circular resistance plate, thereby increasing the volume of the sound when the air flows into the room through the cylindrical part that forms the air intake hole, and it is possible to realize an indoor environment in which it is difficult to hear living sounds from outside, even in a room that does not have an air intake hole facing the exterior wall.
The resistance device is also characterized in that the slit width of the outermost peripheral slit of the circular resistance plate is configured to be changeable.
According to the background noise generating device, it is possible to adjust the volume of the sound generated when air flows into the room through the cylindrical part that forms the air inlet.
The resistance device is also characterized in that the four plate portions of the cross-shaped resistance plate and the four plate portions of the circular resistance plate are arranged so as to face each other while being shifted circumferentially, or that the four plate portions of the cross-shaped resistance plate and the four plate portions of the circular resistance plate are arranged so as to face each other directly.
According to the background noise generating device, it is possible to further increase the volume of the sound generated when air flows into a room through the cylindrical part that forms the air inlet.
The resistance device is also characterized in that the distance between the cross-shaped resistance plate and the circular resistance plate is variable.
According to the background noise generating device, it is possible to adjust the volume of the sound generated when air flows into the room through the cylindrical part that forms the air inlet.

FIG. 1 is a cross-sectional view showing an example of a building that employs a background noise generating device. FIG. 1 is a floor plan showing an example of a building that employs a background noise generating device. FIG. FIG. 1 is a perspective view showing a resistance device (cross-shaft type). 1 is a front view and a rear view of a resistance device (cross-shaft type). 1A is a perspective view, a front view, and a rear view of a resistance device (shaft facing type). FIG. 2 is a perspective view showing a resistance device (cross-shaft type and opposite-shaft type). FIG. 13 shows the experimental results of Experiment 1. FIG. 13 shows the experimental results of Experiment 2. FIG. 13 shows the experimental results of Experiment 3. FIG. 13 shows the experimental results of Experiment 4.

EMBODIMENT 1
As shown in FIG. 1 , the background noise generating device of embodiment 1 is a background noise generating device for a building 10 that is configured to supply air taken into the building 10 from outside to rooms 12 within the building 10 via an attic space 11S, for example a building 10 that employs a first type ventilation method as a 24-hour ventilation system in which outside air is forcibly supplied to the interior of the building 10 from outside and forcibly exhausted from the interior of the building 10 to the outside of the building 10. The background noise generating device is configured to increase the volume of the sound when air flows into the room 12 through the air supply hole 1, thereby realizing an indoor environment in which it is difficult to hear everyday sounds from outside, even in a room 12 that does not have an air supply hole facing the exterior wall 9 of the building 10.
Incidentally, when there is no resistance device 2 inside the air intake 1 to provide resistance to the air passing through, the sound generated when air flows into the room 12 through the air intake 1 is also background noise; strictly speaking, in the present invention, the sound generated when air passes through the resistance device 2 (meaningless sound) is added to the background noise; however, in this specification, the sound that is generated when air passes through the resistance device 2 installed inside the air intake 1 and that can be heard inside the room 12 will be defined and explained as background noise.

As shown in Figures 1 and 2, in a building 10 such as an apartment building (condominium) that employs a Type 1 ventilation method of a 24-hour ventilation system, air is forcibly taken in from the outside of the building 10 into the building 10, distributed to each room 12, 12... inside the building 10, and the air is forcibly exhausted from a specific location to the outside of the building 10.
Therefore, in the background noise generating device of embodiment 1, in order to distribute air taken in from outside the building 10 to the interior of the building 10 to each of the multiple rooms 12, 12... within the building 10, air intake holes 1, 1... are provided in the ceiling panels 11, 11... of each of the multiple rooms 12, 12..., and resistance devices 2, 2... are provided inside each of the air intake holes 1, 1....
For example, as shown in Figures 1 and 2, a building 10 is equipped with an air supply means 13 that takes in outside air from outside the building 10 into the building 10, a heat exchange system 14, an internal air intake hole 17 provided in the ceiling panel 11 of a specific room (e.g. a bedroom), air supply holes 1, 1... provided in each ceiling panel 11, 11... of each room 12, 12..., resistance devices 2, 2... provided inside each air supply hole 1, 1..., and an exhaust means 15 that exhausts air inside the building 10 to the outside of the building 10.

The air supply means 13 is a means for taking in outside air into the attic space 11S, which includes, for example (not shown) a through hole formed in the exterior wall 9 of the building 10, a cylinder that is fitted into the through hole to form an outside air intake hole, and a forced air supply means such as an air supply fan provided on the other end opening side of the cylinder that is closer to the heat exchange system 14.

As shown in FIG. 2, the heat exchange system 14 is a device that performs a heat exchange process between outside air taken in from outside the building 10 by the air supply means 13 and inside air taken in from a specific room (e.g., a bedroom), and then distributes and supplies this air after heat exchange to each room (each room) 12, 12....
The heat exchange system 14 may have an air cleaning function in addition to the heat exchange function.
In the plan view (floor plan) of the building 10 in FIG. 2, E is the entrance, Cd is the corridor, BR is the bedroom, UB is the bathroom with toilet, W is the washroom, K is the kitchen, WR is the Western-style room, C is the closet, JR is the Japanese-style room, and LD is the living-dining room.

As shown in FIG. 3, the air supply hole 1 is formed by a cylindrical part 1A, which is a tubular part with one end opening 1a communicating with the room 12 via a through hole 11a formed in the ceiling board 11 that forms the ceiling, and the other end opening 1b communicating with a duct 16C for taking in air from outside the building 10.

The cylindrical part 1A is composed of a one-end opening side cylindrical portion 1B formed by a cylindrical portion, the other-end opening side cylindrical portion 1C formed by a cylindrical portion having a diameter smaller than the diameter of the one-end opening side cylindrical portion 1B, and a circular ring-shaped blocking plate 1D that blocks the space between the other-end opening edge of the one-end opening side cylindrical portion 1B and the one-end opening edge of the other-end opening side cylindrical portion 1C.
That is, the cylindrical part 1A is a stepped cylindrical part in which two cylindrical parts of different diameters are combined, the cylindrical part 1B having one open end and the cylindrical part 1C having a smaller diameter than the cylindrical part 1B having one open end. In other words, the cylindrical part 1A is a stepped cylindrical part whose cross-sectional shape along the central axis is convex.

Specifically, the air supply hole 1 is formed by an inner through hole 1H of a cylindrical part 1A attached so as to pass through the through hole 11a.
The inner through hole 1H is formed by a stepped inner through hole partitioned by an inner through hole 1HB, which is the inner surface of the cylindrical portion 1B at one end opening, an inner through hole 1HC, which is the inner surface of the cylindrical portion 1C at the other end opening, and the inner surface 1 of the blocking plate 1D.

A mounting flange 1F is provided on the edge of one end opening (lower end opening) 1a of one end opening cylindrical portion 1B of cylindrical part 1A. The cylindrical part 1A is inserted through through hole 11a from the other end opening (upper end opening) 1b of other end opening cylindrical portion 1C, and the upper surface of mounting flange 1F is brought into close proximity with the lower surface of ceiling board 11. Then, for example, a screw or bolt is inserted through mounting flange 1F and ceiling board 11 and fastened to a ceiling substrate (not shown), thereby attaching cylindrical part 1A to ceiling board 11, and air supply hole 1 that communicates room 12 with ceiling space 11S is formed in ceiling board 11.
In addition, it is preferable that a lid 1E equipped with an opening/closing body 1R, such as a louver opening/closing part, for opening and closing the one end opening 1a of the cylindrical part 1A (the room side opening of the air intake hole 1) 1a be removably attached to the one end opening 1a side of the cylindrical part 1A.

The exhaust means 15 is a means configured to exhaust air from inside the building to the outside, and includes, for example, a through hole formed in the ceiling of a specific room 12 (e.g., a bathroom or washroom), a cylinder that is fitted into the through hole to form an internal air exhaust hole, and a forced exhaust means such as an exhaust fan provided on the opening side of the cylinder located in the ceiling space, etc., although not shown.

As shown in FIGS. 1 and 2, an outside air outlet (the other end opening of the above-mentioned cylinder) 13a of the air supply means 13 and an outside air intake 14a of the heat exchange system 14 are connected by a duct 16A.
2, the inside air intake 14b of the heat exchange system 14 and an opening on the underside of the ceiling of the inside air intake hole 17 provided in the ceiling board 11 of the specific room 12 (e.g., a bedroom) are connected by a duct 16B. Note that it is sufficient that there is one or more specific rooms, and that there is also sufficient that there is one or more inside air intake holes 17.
As shown in Figures 1 and 2, the treated air discharge outlet 14c of the heat exchange system 14 is connected to each of the under-ceiling openings of each air supply hole 1, 1... provided in each ceiling panel 11, 11... of each room 12, 12... (the other end opening (upper end opening) 1b of the one-end opening side cylindrical portion 1B of the cylindrical part 1A mentioned above) by ducts 16C, 16C....

In addition, an air supply fan is provided near the outside air intake 14a and the inside air intake 14b of the heat exchange system 14, and an exhaust fan is provided near the treated air outlet 14c of the heat exchange system 14.

Therefore, the outside air taken in from the outside of the building 10 to the inside of the building 10 by the air supply means 13 is taken in by the heat exchange system 14 via the duct 16A and the outside air intake 14a arranged in the ceiling space 11S. Also, the inside air of a specific room 12 (for example, a bedroom) is taken in by the heat exchange system 14 via the inside air intake holes 17 provided in the ceiling board 11, the duct 16B and the inside air intake 14b arranged in the ceiling space 11S. Then, the heat exchange system 14 performs a heat exchange process between the outside air and the inside air, and the air after this heat exchange process is distributed and supplied to each room 12, 12... via the treated air outlet 14c, the ducts 16C, 16C..., the air supply holes 1, 1... provided in each ceiling board 11, 11... of each room 12, 12..., and the resistance devices 2, 2... provided in each air supply hole 1, 1....

In addition, in the first type ventilation method of the 24-hour ventilation system, the amount of air taken in from outside the building 10 to inside the building 10 by the air supply means 13 is adjusted to be equal to the amount of air exhausted from inside the building 10 to outside the building 10 by the exhaust means 15.

As shown in FIG. 3, the background noise generating device according to the first embodiment is configured with a cylindrical part 1A that is provided on the ceiling of the room 12 and forms an air supply hole 1 for supplying air from the ceiling space 11S side to the room 12, and a resistance device 2 that provides resistance when air passes inside the cylindrical part 1A.

As shown in Figure 3, the resistance device 2 comprises a cylindrical body 21 formed with an outer diameter dimension corresponding to the inner diameter dimension of the inner through hole 1HB of the one-end opening cylindrical portion 1B in the cylindrical part 1A that forms the air supply hole and installed inside the one-end opening cylindrical portion 1B, a cross-shaped resistance plate 22 provided on the other end opening 21a side of the cylindrical body 21, and a circular resistance plate 23 provided on the one-end opening 21b side of the cylindrical body 21.
As shown in Figures 4 and 3, the circular resistance plate 23 is a resistance plate that, when attached to the one end opening 21b side of the cylinder 21 and installed inside the cylindrical part 1A, is positioned on the one end opening 1a side to which the flange 1F of the cylindrical part 1A is attached, i.e., on the room 12 side.
In addition, the cross-shaped resistance plate 22 is a resistance plate that, when attached to the other end opening 21a side of the cylinder 21 and installed within the cylindrical part 1A, is positioned on the other end opening 1b side where there is no flange 1F of the cylindrical part 1A, i.e., on the duct 16C side.
That is, as shown in FIG. 3, the resistance device 2 is installed inside the one-end opening cylindrical portion 1B so that the outer peripheral surface of the cylinder 21 and the inner peripheral surface of the inner through hole 1HB of the one-end opening cylindrical portion 1B are closely opposed to each other, the cross-shaped resistance plate 22 is positioned inside the other-end opening side of the one-end opening cylindrical portion 1B, and the circular resistance plate 23 is positioned inside the one-end opening 1a side of the one-end opening cylindrical portion 1B, and is fixedly attached to the inside of the one-end opening cylindrical portion 1B by an attachment means such as welding, adhesive, screwing, engagement means, etc.

As shown in Figures 4 and 5(a), the cross-shaped resistance plate 22 is, for example, a cross-shaped plate with a slit, that is, a cross-shaped plate having a predetermined plate thickness (for example, a plate thickness of about 0.1 mm to 2 mm) and a diameter dimension corresponding to the diameter dimension of the inner or outer circumferential surface of the cylinder 21, and a slit (a through hole penetrating the plate) 24 formed on the inside of the cross-shaped plate.
That is, the cross-shaped resistance plate 22 comprises a square-shaped central plate portion 25 located at the intersection of the cross, and four plate portions 26, 26... extending in all directions from each side of the square of the square-shaped central plate portion 25 and connected to the other end opening 21a of the cylinder 21.
The slits 24 are formed in the center of each of the plate portions 26, 26 . . . along the extension direction of each of the plate portions 26, 26 .
Furthermore, the extended end sides of each of the four plate portions 26, 26... of the cross-shaped resistance plate 22 are connected to the inner surface on the other end opening 21a side of the cylinder 21 or to the opening edge of the other end opening 21a of the cylinder 21 by connecting means such as welding, adhesive, screwing, engaging means, etc., so that the cross-shaped resistance plate 22 is provided on the other end opening 21a side of the cylinder 21.

As shown in Figures 4 and 5 (b), the circular resistance plate 23 is formed, for example, based on a circular plate having a predetermined plate thickness (for example, a plate thickness of about 0.1 mm to 2 mm) and a diameter dimension corresponding to the diameter dimension of the inner or outer circumferential surface of the cylindrical body 21.
In other words, the circular resistance plate 23 is a circular plate in which four portions spaced 90° from one another on the outer periphery of the circular plate, based on the center of the above-mentioned circular plate, are left as connection portions 31 and connected to one end opening 21b of the cylinder 21, and the outer periphery of the circular plate is removed by approximately a few millimeters along the outer periphery to form a circular outer periphery 32, and a circular hole 33 is formed inside the circular plate, centered on the center of the original circular plate, and further, a plurality of arc-shaped slits 34, 35, 38 are formed around the outer periphery of the circular hole 33, resulting in a circular plate with concentric arc-shaped slits.

Furthermore, four portions spaced 90° from one another with respect to the center of the original circular plate (the center of the circular hole 33) are left as four plate sections 36, 36... that are continuous with the connection section 31 and extend toward the center of the original circular plate, and arc-shaped slits 34, 35, 38 centered on the center of the original circular plate are formed in the arc-shaped plate sections 37, 37... between circumferentially adjacent plate sections 36 and 36.
The outermost periphery slit 38 formed on the outermost side of the circular resistance plate 23 is a slit whose slit width is the distance between the circular outer periphery 32 and the inner periphery surface of the cylinder 21. In other words, the outermost periphery slit 38 is formed by the space between the circular outer periphery 32 and the inner periphery surface of the cylinder 21.
The slits 34, 34... formed in each of the four plate portions 36, 36... are arc-shaped slits formed along a circumference of a predetermined radius centered on the center of the circular hole 33.
The slits 35, 35... formed in each of the four plate portions 36, 36... are arc-shaped slits formed along a circumference having a radius larger than the above-mentioned predetermined radius and centered at the center of the circular hole 33.

The four connection portions 31, 31... of the circular resistance plate 23 are connected to the inner surface on the one end opening 21b side of the cylinder 21 or to the opening edge of the one end opening 21b of the cylinder 21 by connecting means such as welding, adhesive, screwing, engagement means, etc., so that the circular resistance plate 23 is provided on the one end opening 21b side of the cylinder 21, and arc-shaped outermost slits 38, 38... are formed between the inner surface of the cylinder 21 and the circular outer periphery 32 of the circular resistance plate 23.
That is, the circular resistance plate 23 is configured to have arc-shaped slits 34, 35, 38 formed in order from the side closest to the center of the circular hole 33, that is, it is a slitted circular plate provided with a plurality of concentric arc-shaped slits 34, 35, 38.

The resistance device 2 may be a resistance device 2 (hereinafter referred to as an axial cross type) in which the plate portions 26, 26... of the cross-shaped resistance plate 22 and the plate portions 36, 36... of the circular resistance plate 23 are arranged to face each other with a circumferential shift, as shown in Figures 4 and 5, or a resistance device 2A (hereinafter referred to as an axially facing type) in which the plate portions 26, 26... of the cross-shaped resistance plate 22 and the plate portions 36, 36... of the circular resistance plate 23 are arranged to face each other directly, as shown in Figure 6, in which the plate portions 26, 26... of the cross-shaped resistance plate 22 and the plate portions 36, 36... of the circular resistance plate 23 are not arranged to face each other directly, as shown in Figure 6.

Then, as shown in FIG. 3, a cylindrical part 1A is manufactured with a resistance device 2 or resistance device 2A attached to the inside of one-end opening cylindrical portion 1B. Next, the cylindrical part 1A is attached to the ceiling board 11 as described above so that the circular resistance plate 23 is positioned closer to the room 12 and the cross-shaped resistance plate 22 is positioned farther from the room 12, i.e., on the ceiling space 11S side (duct side). Then, in the ceiling space 11S, the other end opening (upper end opening) 1b of the other end opening cylindrical portion 1C of the cylindrical part 1A is connected to the duct 16C, thereby installing a background noise generating device on the ceiling of the room 12.

In the background noise generating device of embodiment 1, a cylindrical part 1A forming an air intake 1 is configured to include a one-end opening cylindrical portion 1B and an other-end opening cylindrical portion 1C formed by a cylindrical portion having a diameter smaller than the diameter of the one-end opening cylindrical portion 1B, and the resistance device 2 or resistance device 2A is configured to include a cylinder 21 formed to an outer diameter dimension corresponding to the inner diameter dimension of the one-end opening cylindrical portion 1B of the cylindrical part 1A and installed inside the one-end opening cylindrical portion 1B, a cross-shaped resistance plate 22 provided on the other-end opening side of the cylinder 21, and a circular resistance plate 23 provided on the one-end opening side of the cylinder 21, with the cross-shaped resistance plate 22 being positioned inside the other-end opening 1a side of the one-end opening cylindrical portion 1B of the cylindrical part 1A, and the circular resistance plate 23 being positioned inside the one-end opening side of the one-end opening cylindrical portion 1B of the cylindrical part 1A.
According to this background noise generating device, a cylindrical part 1A is used that has one open-end cylindrical portion 1B and the other open-end cylindrical portion 1C formed by a cylindrical portion with a smaller diameter than the diameter of the one open-end cylindrical portion 1B. Therefore, a duct with a small diameter dimension corresponding to the diameter of the other open-end cylindrical portion 1C can be used as a duct for taking in air from outside the building. As shown in Figure 1, a duct 16C with a relatively small inner diameter can be piped into the attic space 11S. Therefore, the height dimension S of the attic space 11S can be designed to be as low as possible, and the interior space of the room 12 can be designed to be spacious.
In addition, the speed of the air (wind) passing through the duct 16C having a small diameter and the cylindrical portion 1C having the other end opening of the cylindrical part 1A having a small diameter can be reduced in the cylindrical portion 1B having one end opening of the cylindrical part 1A and sent to the room 12.
Furthermore, with this background noise generating device, the air flowing into the cylindrical part 1A via the duct 16C passes through the cross-shaped resistance plate 22 and the circular resistance plate 23, increasing the volume of the sound when the air flows into the room 12 through the cylindrical part 1A which forms the air intake 1, making it possible to realize an indoor environment in which it is difficult to hear everyday sounds from outside, even in a room 12 which does not have an air intake 1 facing the exterior wall 9.

Furthermore, according to the background noise generating device of embodiment 1, when air is distributed and supplied to each of the rooms 12, 12... from the heat exchange system 14 via the ducts 16C, 16C... and the air intakes 1, 1... provided in the ceiling panels 11, 11... of each of the rooms 12, 12..., sound is generated due to resistance or the like when the air passes through the resistance device 2 or resistance device 2A provided in each of the air intakes 1, 1.... In other words, the volume of sound when air flows into the room 12 via the cylindrical part 1A forming the air intake 1, and the resistance device 2 or resistance device 2A can be increased.
Therefore, even in a room 12 that does not have an air supply hole 1 facing the outer wall 9 of the building 10, an indoor environment in which outside living sounds are difficult to hear can be realized. Also, an indoor environment in which outside living sounds are difficult to hear can be realized for each of a plurality of rooms 12, 12....
In addition, by adopting the first type ventilation system as the ventilation system for the building, ventilation can be smooth, and an indoor environment can be achieved in room 12 in which it is difficult to hear everyday sounds from outside.

That is, first, the air from the heat exchange system 14 passes through the small-diameter duct 16C and the other end opening side cylindrical portion 1C of the cylindrical part 1A at an increased speed and collides with the central plate portion 25 of the cross-shaped resistance plate 22, generating noise, and therefore the volume of the noise increases when the air flows into the room 12 through the cylindrical part 1A that forms the air intake vent 1.
In addition, after the air collides with the central plate portion 25 of the cross-shaped resistance plate 22, it passes between each plate portion 26, 26 of the cross-shaped resistance plate 22 and through the slits 24, and then through the circular hole 33 and the arc-shaped slits 34, 35, 38 of the circular resistance plate 23, thereby increasing the volume of the sound when the air flows into the room 12 through the cylindrical part 1A that forms the air intake vent 1.

EMBODIMENT 2
The circular resistance plate 23 of the resistance device 2 (cross-shaft type) or the resistance device 2A (front-facing shaft type) may be configured without the central circular hole 33 as shown in Fig. 7. In other words, the circular resistance plate 23 may be configured without the central circular hole 33, with the central portion being a wall portion 39 without the circular hole 33, and with only the above-mentioned slits 34, 35, 38 as through holes.
That is, as shown in Fig. 7(a) and (b) in the second embodiment, the circular resistance plate 23 of the resistance device 2 (shaft cross type) or the resistance device 2A (shaft facing type) is formed based on a circular plate whose diameter corresponds to that of the cylinder 21, and four parts on the outer circumference of the circular plate that are 90° apart from each other with respect to the center of the circular plate are left as connecting parts 31 and connected to the one end opening 21b side of the cylinder 21, and the outer circumference of the circular plate is removed along the outer circumference to form a circular plate formed on the circular outer circumference. In addition, the four parts that are 90° apart from each other with respect to the center of the circular plate are left as four plate parts 36 that are continuous with the connecting parts 31 and extend toward the center of the circular plate, and the circular arc-shaped plate parts between the plate parts 36 adjacent to each other in the circumferential direction have circular arc-shaped slits 34, 35 centered on the center of the circular plate, and the outermost circumference slit 38 is formed by the space between the circular outer circumference and the inner circumference of the cylinder 21.
In addition, Figure 7 (a) shows an oblique view of an axial cross type resistance device 2 in which the central portion of the circular resistance plate 23 is formed in a wall portion 39 where no circular hole 33 is formed, and the only through holes are slits 34, 35, 38, and Figure 7 (b) shows an oblique view of an axial facing type resistance device 2A in which the central portion of the circular resistance plate 23 is formed in a wall portion 39 where no circular hole 33 is formed, and the only through holes are slits 34, 35, 38.

According to the background noise generating device of the second embodiment, when the air that flows into the cylindrical part 1A forming the air intake 1 passes through the cross-shaped resistance plate 22 and the circular resistance plate 23, the air collides with the central plate portion 25 of the cross-shaped resistance plate 22, passes between the plate portions 26, 26 of the cross-shaped resistance plate 22 and the slits 24, collides with the wall portion 39 in the center of the circular resistance plate 23, or passes through the slits 34, 35, 38 of the circular resistance plate 23. As a result, the volume of the sound generated when the air flows into the room 12 through the cylindrical part 1A forming the air intake 1 becomes large, and an indoor environment in which it is difficult to hear everyday sounds from outside can be realized even in a room 12 that does not have an air intake 1 facing the exterior wall 9.

In order to verify the effectiveness of the background noise generating device of the present invention, the following experiment was conducted.

- Experimental method A ceiling model simulating a ceiling was installed in an anechoic chamber, cylindrical part 1A was penetrated through the ceiling model to form air supply hole 1, and a resistance device (resistance device 2 (axial cross type) or resistance device 2A (axial facing type)) was installed inside inner through hole 1HB of one-end opening side cylindrical portion 1B of cylindrical part 1A forming air supply hole 1. That is, a resistance device was installed inside one-end opening side cylindrical portion 1B so that circular resistance plate 23 was located at one-end opening side of one-end opening side cylindrical portion 1B and cross-shaped resistance plate 22 was located at the other-end opening side of one-end opening side cylindrical portion 1B, and an experimental device was fabricated in which air passed from the other-end opening side of cylindrical part 1A in which the resistance device was installed to the one-end opening side, and differences in effect due to differences in test specimens of the resistance device were verified.
In the experiment, a sealed box was provided on the back surface of the ceiling model to surround the other end opening side of the cylindrical part 1A, and this sealed box and the blower fan were connected by a duct of approximately 20 m. A sound-absorbing box was also installed midway along the duct, and air was sent from the blower fan to the resistance device inside the sealed box so that the sound generated by the blower fan would not be measured.
In the measurement of the 1/3 octave band sound pressure level and the A-weighted sound pressure level, the center position of the head case of the microphone was fixed at a position 1 m away from the center position of one end opening of the cylindrical part 1 A. The center positions of the head case of the microphone and the center positions of the one end opening of the cylindrical part 1 A were set at a height of 1.4 m from the floor of the anechoic chamber.
The blower fan was then driven and the sound pressure level of the sound generated when the wind passed through the resistor device was measured.
Since the operating noise is a steady sound, the equivalent sound pressure level was determined for 20 seconds.
The ventilation volume was measured using an airflow meter.

Experiment 1
An experiment to verify the relationship between air volume and A-weighted sound pressure level depending on the differences in each test specimen.
Experiment 2
An experiment to verify how the 1/3 octave band sound pressure level and A-weighted sound pressure level change depending on the differences in each test specimen.
Experiment 3
An experiment to verify the relationship between air volume and A-weighted sound pressure level by changing the slit width of the outermost peripheral slit 38 of the circular resistance plate 23.
Experiment 4
An experiment to verify how the A-weighted sound pressure level changes when the distance between the cross-shaped resistance plate 22 and the circular resistance plate 23 is changed.

In Experiments 1 to 4, the cylindrical part 1A and the resistance device used had the following specifications.
(1) Cylindrical part 1A
・Total length: 130mm.
- The inner diameter of the cylindrical portion 1B at one opening end is 99.6 mm, and the overall length of the cylindrical portion of the cylindrical portion 1B at one opening end is 70 mm.
The inner diameter of the other end opening side cylindrical portion 1C is 48.8 mm, and the overall length of the other end opening side cylindrical portion 1C is 60 mm.
・Plate thickness: 0.6 mm.
(2) Resistance device 2, resistance device 2A
The length of the cylindrical body 21 was 50 mm (except for Experiment 4), and the outer diameter was 90 mm.
The length of one side of the regular rectangle of the central plate portion 25 of the cross-shaped resistance plate 22 is 15 mm, the plate width of the plate portion 26 is 15 mm, the slit width of the slit 24 is 5 mm, and the length of the slit 24 is 30 mm.
The slit width of the innermost slit 34 of the circular resistance plate 23 is 1.5 mm, the slit width of the intermediate slit 35 located between the innermost slit 34 and the outermost slit 38 is 2 mm, and the plate width of the plate portion 36 is 10 mm.
- If a circular hole 33 is provided, the diameter of the circular hole 33 is 40 mm.

The test specimens measured in Experiments 1 and 2 are as follows:
Test specimen A=a test specimen not equipped with a resistance device within the cylindrical part 1A.
Test specimen B: A test specimen equipped with an axial cross type (embodiment 1) resistance device equipped with a circular resistance plate having a circular hole and a slit within a cylindrical part 1A.
- Test specimen C = A test specimen equipped with an axial cross type (embodiment 2) resistance device equipped with a circular resistance plate having only a slit without a circular hole within the cylindrical part 1A.
Test specimen D: A test specimen equipped with an axially facing type resistance device (embodiment 1) equipped with a circular resistance plate having a circular hole and a slit within a cylindrical part 1A.
- Test specimen E = A test specimen equipped with an axially facing type resistance device (embodiment 2) having a circular resistance plate having only a slit without a circular hole within a cylindrical part 1A.

In experiment 1, for each of the test specimens A to E, it was verified how the A-weighted sound pressure level changed when the amount of air passing through was changed.
The results of Experiment 1 are shown in FIG.
The results of Experiment 1 revealed the following trends.
(1) In each of the test specimens A to E, the sound generated (A-weighted sound pressure level) increases as the air volume increases.
(2) In the case of test specimens B to E equipped with a resistance device, the sound generated (A-weighted sound pressure level) is greater than that of test specimen A which does not have a resistance device.
(3) In particular, in the case of test specimens C and E, which use a resistance device having a circular resistance plate having only slits and no circular holes, the generated sound (A-weighted sound pressure level) is large.

In experiment 2, the air volume was set to 40.0 m ³ /h, and the 1/3 octave band center frequency vs. sound pressure level was measured for each of test specimens A to E.
The results of Experiment 2 are shown in FIG.
The results of Experiment 2 revealed the following trends.
(1) In the case of test specimens B to E equipped with a resistance device, the sound (sound pressure level) generated is greater, especially in the mid-to-high frequency bands, compared to test specimen A which does not have a resistance device.
(2) In the case of test specimens C and E, which use a resistance device equipped with a circular resistance plate having only a slit and no circular hole, there is a tendency for the sound generated (sound pressure level) to become louder, especially in the frequency band of 1 kHz or higher.

In Experiments 1 and 2, the resistance device was installed inside the cylindrical portion 1B at the one end opening so that the center of the opening at the boundary between the cylindrical portion 1B at the one end opening and the cylindrical portion 1C at the other end opening coincided with the center of the central plate portion 25 of the cross-shaped resistance plate 22.Therefore, the air flowing fast through the duct and the cylindrical portion 1C at the other end opening collides with the central plate portion 25 of the cross-shaped resistance plate 22, passes between adjacent plate portions 26 and through the slits 24, enters the inside of the resistance device, and passes through the circular hole 33 and slits 34, 35, 38 of the circular resistance plate 23, or passes through the slits 34, 35, 38 of the circular resistance plate 23.
In this case, first, the air passing through the duct and the other end opening side cylindrical portion 1C flows at a high speed and collides with the central plate portion 25, so that the generated sound (sound pressure level) becomes large.
Furthermore, since sound is generated when the air passes through the slits 34, 35, and 38 of the circular resistance plate 23, the generated sound (sound pressure level) becomes louder.
Furthermore, if the circular resistance plate 23 does not have the circular hole 33, the air collides with the wall portion 39 that does not have the circular hole 33, and the generated sound (sound pressure level) becomes even louder.

The results of Experiments 1 and 2 show that when a resistor device is used that has a circular resistor plate 23 that does not have a circular hole 33 and only has slits 34, 35, and 38, the volume of the sound generated when air flows into the room through the cylindrical part 1A that forms the air intake 1 increases, and it is possible to realize an indoor environment in which it is difficult to hear everyday sounds from outside, even in a room 12 that faces an exterior wall 9 and does not have an air intake 1.

The test specimens measured in Experiment 3 are as follows:
Test piece 1 = Test piece not equipped with a resistance device within the cylindrical part 1A.
Test piece 2 = a test piece equipped with an axial cross type resistance device equipped with a circular resistance plate having only slits and the width of the outermost peripheral slit 38 being 1 mm within the cylindrical part 1A.
Test piece 3 = a test piece equipped with an axial cross type resistance device equipped with a circular resistance plate having only slits and the width of the outermost peripheral slit 38 being 5 mm within the cylindrical part 1A.
Test piece 4 = a test piece equipped with a resistance device of the shaft-facing type equipped with a circular resistance plate having only slits and the width of the outermost peripheral slit 38 being 1 mm within the cylindrical part 1A.
Test piece 5=a test piece equipped with a resistance device of the shaft-facing type equipped with a circular resistance plate having only slits and the width of the outermost peripheral slit 38 being 5 mm within the cylindrical part 1A.

In experiment 3, for each of test specimens 1 to 5, it was verified how the A-weighted sound pressure level changed when the amount of air passing through was changed.
The results of Experiment 3 are shown in FIG.
The results of Experiment 3 revealed the following trends.
(1) In each of the test specimens 1 to 5, the sound generated (A-weighted sound pressure level) increases as the air volume increases.
(2) In the case of test specimens 2 to 5 equipped with a resistance device, the sound generated (A-weighted sound pressure level) is louder than that of test specimen 1 which does not have a resistance device.
(3) In particular, it was found that the volume of the generated sound changes by changing the width of the outermost circumferential slit 38, and in the case of test specimens 2 and 4 using a resistance device equipped with a circular resistance plate with an outermost circumferential slit 38 having a width of 1 mm, the generated sound (A-weighted sound pressure level) tends to be larger than that of test specimens 3 and 5 using a resistance device equipped with a circular resistance plate with an outermost circumferential slit 38 having a width of 5 mm.

In experiment 4, in the cross-shape type and directly-facing-shape type resistance devices, the distance between the cross-shaped resistance plate 22 and the circular resistance plate 23 was changed to 10 mm, 20 mm, and 30 mm, that is, the total length of the cylinder 21 was changed, and the A-weighted sound pressure level was measured to verify how the A-weighted sound pressure level changed depending on the distance. Note that the measurement in experiment 4 was performed at an air volume of 20 ^m3 /h.
The axial cross type resistance device used was a circular resistance plate having only slits, with the width of the outermost peripheral slit 38 being 1 mm.
The shaft facing type resistance device used was a shaft facing type resistance device equipped with a circular resistance plate having only slits, with the width of the outermost peripheral slit 38 being 1 mm.

The results of Experiment 4 are shown in FIG.
The results of Experiment 4 revealed the following trends.
(1) It was found that the volume of the generated sound changes by changing the distance between the cross-shaped resistance plate 22 and the circular resistance plate 23, and that narrowing the distance tends to increase the generated sound, and widening the distance tends to decrease the generated sound.

EMBODIMENT 3
In the first and second embodiments, a background noise generating device has been exemplified in which a resistance device having a cylinder 21, a cross-shaped resistance plate 22, and a circular resistance plate 23 is installed inside the cylindrical portion 1B at one opening end of the cylindrical part 1A. However, the background noise generating device may also be configured in such a way that the cross-shaped resistance plate 22 and the circular resistance plate 23 are directly attached to the inner surface of the cylindrical portion 1B at one opening end of the cylindrical part 1A.
In other words, the background noise generating device may be configured such that the cross-shaped resistance plate 22 and the circular resistance plate 23 are directly attached to the inner surface of the one-end opening cylindrical portion 1B so that the cross-shaped resistance plate 22 is positioned inside the other end opening side of the one-end opening cylindrical portion 1B and the circular resistance plate 23 is positioned inside the one-end opening 1a side of the one-end opening cylindrical portion 1B.

EMBODIMENT 4
Taking into consideration the above-mentioned Experiment 3, in embodiment 4, a background noise generating device is provided that is capable of changing the slit width of the outermost peripheral slits 38 of the circular resistance plate 23. That is, in order to make the slit width of the outermost peripheral slits 38 of the circular resistance plate 23 variable, the background noise generating device is provided with a plurality of types of circular resistance plates 23 that are formed so that the distance from the center of the circular resistance plate 23 to the circular outer peripheral edge 32 varies, and these plurality of types of circular resistance plates 23 are configured to be detachable from the inner circumferential surface on the one end opening 21b side of the cylinder 21 or the other end side of the one-end opening side cylindrical portion 1B.
According to the background noise generating device of embodiment 4, it is possible to provide a background noise generating device that can adjust the volume of the sound when air flows into room 12 through air intake 1, i.e., the volume of the generated background noise, by adjusting the slit width of the outermost peripheral slits 38.

EMBODIMENT 5
Taking into consideration the above-mentioned experiment 4, in the fifth embodiment, a background noise generating device is configured so that the distance between the cross-shaped resistance plate 22 and the circular resistance plate 23 is variable.
According to the background noise generating device of embodiment 5, by adjusting the distance between the cross-shaped resistance plate 22 and the circular resistance plate 23, it is possible to provide a background noise generating device that can adjust the volume of the sound when air flows into the room 12 through the air intake 1, i.e., the volume of the generated background noise.

In the embodiment, an example has been shown in which the background noise generating device and the inside air intake hole are provided on the ceiling, but the background noise generating device and the inside air intake hole 17 may be provided on the floor. In this case, the air supply means, the heat exchange system, the ducts, etc. may be provided in the space under the floor.
That is, by attaching the background noise generating device of the present invention to a floorboard, it is possible to increase the volume of sound when air flows into room 12 through said background noise generating device. Also, it becomes possible to design the underfloor space through which the duct passes as narrow as possible, thereby enabling the interior space to be designed to be spacious. Also, it becomes possible to reduce the speed of the air (wind) that has passed through a duct with a small diameter at the cylindrical portion 1C on the other end opening side of cylindrical part 1A and send it into room 12.

Further, the background noise generating device and the inside air intake hole 17 may be provided in a partition wall having an inner space. In this case, the ducts and the like may be provided in the inner space.
That is, by attaching the background noise generating device of the present invention to a wall panel, it is possible to increase the volume of sound when air flows into room 12 through the background noise generating device. Also, it becomes possible to design the space within the wall through which the duct passes as narrow as possible, thereby enabling the indoor space to be designed to be spacious. Also, it becomes possible to reduce the speed of the air (wind) that has passed through a duct with a small diameter at the cylindrical portion 1C on the other end opening side of cylindrical part 1A before sending it into room 12.

A resistance device may also be provided inside the inside air intake hole 17 to form a background noise generating device.

A configuration without a heat exchange system may also be used.
In this case, the forced air supply means and/or the forced exhaust means may not be provided.
In such a case, an air supply fan can be installed in the air supply hole 1 to supply air from outside the building through the attic space, under-floor space, and space within the walls into the room.

In addition, in the embodiment, an example was shown in which a background noise generating device was provided on the ceiling of each of the multiple rooms in the building in order to distribute the air taken in from the outside of the building to each of the multiple rooms in the building, but it is not necessary to have a configuration in which the air is distributed to each of the multiple rooms in the building. In other words, by providing a background noise generating device on the ceiling, floor, or partition wall of a specific room in the building, it is possible to increase the volume of the sound when air flows into the room through the background noise generating device.

The cylinder of the air supply means 13, the cylindrical part 1A as the tubular part forming the air supply hole 1, and the cylinder of the exhaust means 15 described above do not necessarily have to be cylindrical, and may be, for example, a square cylinder or other cylindrical body.

In the embodiment, a stepped cylindrical part 1A including a one-end opening cylindrical part and an other-end opening cylindrical part having a diameter smaller than that of the one-end opening cylindrical part is exemplified as the cylindrical part forming the air supply hole 1, but a configuration including an other-end opening conical cylindrical part may be used instead of the other-end opening cylindrical part. That is, instead of the other-end opening cylindrical part, a cylindrical part including an other-end opening conical cylindrical part formed so that the diameter gradually increases from the other end of the cylindrical part to the one-end opening cylindrical part may be used.
The tubular part forming the air supply hole 1 may be a conical or pyramidal tubular part whose diameter gradually increases from the other end opening toward the one end opening of the tubular part. In this case, the resistance device installed inside the tubular part may be a conical or pyramidal tubular body.

In other words, the tubular part forming the air intake 1 is formed by a tubular part having one end opening that communicates with the room 12 via a through hole formed in the ceiling panel 11 that forms the ceiling, or the floor panel that forms the floor, or the wall panel that forms the partition wall, and the other end opening that communicates with a duct for taking in air from outside the building, and the tubular part forming the air intake 1 should be configured so that the diameter dimension of the other end opening connected to the duct is smaller than the diameter dimension of the one end opening.
In the present invention, the background noise generating device may be configured such that the resistance device is installed inside the tubular part so that the cross-shaped resistance plate is positioned on the duct side and the circular resistance plate is positioned on the room side.

The resistance device may also be configured to include only one of a circular resistance plate and a cross-shaped resistance plate.
That is, the resistance device may have any configuration as long as it provides resistance when air passes through the inside of the air supply hole.

The material of the cylindrical part and the resistance device are not particularly limited. For example, the cylindrical part and the resistance device may be made of synthetic resin, metal, etc.

The cylindrical parts and resistance devices may be molded as a single piece using a 3D (three-dimensional) printer, etc.

In addition, in the embodiment, an apartment building or other shared housing unit is used as an example of a building, but the present invention can also be applied to detached houses, hotels, offices, and other buildings.

1 Air supply hole, 1A Cylindrical part (tube part), 1B One end opening side cylindrical part,
1C: other end opening side cylindrical portion; 1D: closing plate; 2, 2A: resistance device; 10: building;
11 Ceiling plate, 12 Room, 21 Cylinder, 22 Cross-shaped resistance plate, 23 Circular resistance plate,
24 Slit, 25 Central plate portion, 26 Plate portion, 31 Connection portion, 32 Circular outer periphery,
33 circular hole, 34, 35 slit, 36 plate portion, 37 arcuate plate portion,
38 Outermost slit.

Claims (6)

The system comprises an air supply hole provided in a ceiling, floor, or partition wall of a room for supplying air from the ceiling space side, the underfloor space side, or the wall space side to the room, and a resistance device that provides resistance when air passes inside the air supply hole;
the air supply hole is formed by a cylindrical part having an opening at one end which communicates with the room via a through hole formed in a ceiling board forming the ceiling, or a through hole formed in a floor board forming the floor, or a through hole formed in a wall board forming the partition wall, and an opening at the other end which communicates with a duct for taking in air from outside the building;
the tubular part forming the air supply hole is configured such that the diameter dimension of the other end opening side connected to the duct is smaller than the diameter dimension of the one end opening side, and is configured by a cylindrical part including a one end opening side cylindrical portion formed by a cylindrical portion, an other end opening side cylindrical portion formed by a cylindrical portion having a smaller diameter than the diameter of the one end opening side cylindrical portion, and a blocking plate blocking the gap between the other end opening edge of the one end opening side cylindrical portion and the one end opening edge of the other end opening side cylindrical portion,
The resistance device is installed inside the cylindrical portion at one end opening, and includes a cylindrical body formed to have an outer diameter dimension corresponding to the inner diameter dimension of the cylindrical portion at one end opening and installed inside the cylindrical portion at one end opening, a circular resistance plate provided on the cylindrical body at one end opening, and a cross-shaped resistance plate provided on the cylindrical body at the other end opening,
The cross-shaped resistance plate is positioned inside the other end opening side of the cylindrical portion on the one end opening side of the cylindrical part, and the circular resistance plate is positioned inside the one end opening side of the cylindrical portion on the one end opening side of the cylindrical part,
The cross-shaped resistance plate is
A cross-shaped plate with a slit is formed on the inside of the cross-shaped plate having a diameter dimension corresponding to the diameter dimension of the cylinder,
The cylinder includes a central plate portion located at the intersection of the cross and four plate portions extending in all directions from the central plate portion and connected to the other end opening side of the cylinder,
A background noise generating device characterized in that a slit is formed in the center of each plate portion along the extension direction of each plate portion . The circular resistor plate is
2. The background noise generating device according to claim 1, characterized in that the device is formed on the basis of a circular plate whose diameter corresponds to that of a cylinder, four portions on the outer periphery of the circular plate spaced 90° from one another with respect to the center of the circular plate as a reference are connected to one open end of the cylinder, the outer periphery of the circular plate is removed along the outer periphery to form a circular plate formed on the circular outer periphery, and the four portions spaced 90° from one another with respect to the center of the circular plate as a reference are left as four plate portions continuing from the connecting portions and extending toward the center of the circular plate, an arc-shaped slit centered on the center of the circular plate is formed in the arc-shaped plate portion between adjacent plate portions in the circumferential direction, and an outermost periphery slit is formed by the space between the circular outer periphery and the inner periphery of the cylinder . The circular resistor plate is
2. The background noise generating device according to claim 1, characterized in that the device is formed on the basis of a circular plate having a diameter dimension corresponding to that of a cylinder, a circular hole is formed in the center of the circular plate, four portions on the outer periphery of the circular plate spaced apart by 90° from one another with respect to the center of the circular plate as a reference are connected to one open end of the cylinder, and the outer periphery of the circular plate is formed into a circular plate formed on the circular outer periphery by removing the outer periphery, and the four portions spaced apart by 90° from one another with respect to the center of the circular plate as a reference are left as four plate portions continuing from the connecting portions and extending toward the center of the circular plate, an arc-shaped plate portion between adjacent plate portions in the circumferential direction is formed with an arc-shaped slit centered on the center of the circular plate, and an outermost periphery slit is formed by the space between the circular outer periphery and the inner periphery of the cylinder . The resistance device is
4. The background noise generating device according to claim 2 , wherein the width of the outermost circumferential slit of the circular resistor plate is variable. The resistance device is
A configuration in which the four plate portions of the cross-shaped resistance plate and the four plate portions of the circular resistance plate are arranged to face each other while being shifted in the circumferential direction;
Or,
5. The background noise generating device according to claim 2, wherein the four plate portions of the cross-shaped resistance plate and the four plate portions of the circular resistance plate are arranged so as to face each other. The resistance device is
6. The background noise generating device according to claim 1, wherein the distance between the cross-shaped resistance plate and the circular resistance plate is variable.

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