JP2021029003A - Acoustic device - Google Patents

Abstract

To provide an acoustic device which has a structure capable of preventing a cone paper part of a speaker from being deformed or damaged even when a sudden temperature change occurs, and quickly recovering to a state of capable of performing a normal sound production operation.SOLUTION: In an acoustic device, an inner space A of a main body case 2 and an outer space B are separated with an oscillation body 15 as a border. The acoustic device comprises: an elastic member 21 in which one surface is in contact with the inner space A and the other surface is in contact with the outer space B, and which is deformed by a difference between pressures applied to both surfaces of them; a communication hole 21a communicating the inner space A and the outer space B; and a ventilation member 22 which is provided so as to cover the communication hole 21a, permits passage of air, and blocks passage of fluid.SELECTED DRAWING: Figure 5

Description

The present invention relates to an audio device having a main body case and a speaker unit.

In general, audio equipment such as a warning sound generating speaker and a bathroom speaker mounted on a car needs to be watertight in the main body case because it is necessary to prevent water from entering the internal structure of the equipment. However, this type of audio equipment may be submerged in low-temperature or high-temperature water instead of normal-temperature water, causing a sudden temperature change in the air inside the main body case. Due to this sudden temperature change, the air inside the main body case thermally expands or contracts, and the diaphragm is drawn inside, or conversely, the diaphragm is pushed out, causing deformation or breakage of the diaphragm. There is a risk that it will end up.

Therefore, in the audio equipment described in Patent Document 1 below, an internal space is partitioned inside the equipment, a speaker is provided at a boundary portion inside the equipment, and a diaphragm that seals the internal space is provided. In addition, the diaphragm cover that covers the diaphragm is formed with ventilation holes that communicate with the external space. When the pressure in the internal space changes due to a temperature change, the diaphragm operates to prevent deformation and damage of the cone paper portion of the speaker.

JP-A-2002-34569

In the invention described in Patent Document 1, a speaker is provided in an internal space partitioned by a remote control case and a diaphragm-shaped member, and the internal space is sealed and does not communicate with the external space. Therefore, it is difficult to completely eliminate the pressure difference between the internal space and the external space. Further, even if the environmental temperature stabilizes after the pressure in the internal space changes, the pressure change in the internal space tends to remain because there is no means for assimilating the pressure in the internal space and the pressure in the external space. Therefore, the state in which the cone paper portion of the speaker remains displaced by the pressure is likely to continue.

Therefore, the cone paper portion of the speaker is pulled in or pushed out into the main body case, and is held at a position deviated from the normal neutral position. Further, when the pressure difference between the internal space and the external space remains, the diaphragm-shaped member is displaced, and the capacity inside the main body case is maintained in a state changed from the normal value. If the sounding operation is performed in that state, there is a problem that the acoustic characteristics of the sounding frequency band are changed and the acoustic characteristics may be deteriorated more than usual.

The present invention has been made to solve the above problems, and can eliminate the pressure difference between the internal space provided with the speaker unit and the external space, and when a sudden temperature change occurs, the vibrating body It is an object of the present invention to provide an acoustic device having a structure capable of preventing excessive displacement, preventing deformation and destruction of a vibrating body, and realizing stable sounding operation.

In the present invention, a main body case and a speaker unit fixed in the main body case are provided, and the speaker unit includes a magnetic circuit portion including a magnet and a coil on which a magnetic field generated in the magnetic circuit portion acts. In an acoustic device having a vibrating body that vibrates with the coil.
The internal space and the external space of the main body case are partitioned by the vibrating body as a boundary, and one surface is in contact with the internal space and the other surface is in contact with the external space due to the difference in pressure acting on both surfaces. It is provided with a deformable elastic member, a communication hole that communicates the internal space and the external space, and a ventilation member that is provided so as to cover the communication hole to allow the passage of air and block the passage of fluid. It is characterized by that.

The communication hole is preferably provided in the elastic member.

The position where the communication hole is provided is preferably the position of the center of gravity of the elastic member.

It is preferable that the maximum displacement amount of the elastic member is larger than the maximum displacement amount of the vibrating body with respect to the same pressure acting on the vibrating body and the internal space acting on the elastic member.

The peripheral edge portion of the elastic member is fixed to the main body case, and the elastic member has a deformable ridge portion that bulges toward at least one of the internal space and the external space along the peripheral edge portion. It is preferable that it is provided.

The elastic member is preferably made of rubber.

Since the acoustic device of the present invention is provided with a communication hole for communicating the internal space and the external space, the air in the internal space and the air in the external space can freely move in each other's space, and in a normal environment. It is possible that the pressure in the internal space does not fluctuate due to temperature changes. Therefore, it is possible to always prevent the influence of sound quality due to temperature change, for example, fluctuation of acoustic characteristics in the sound frequency band. Furthermore, since an elastic member that separates the internal space from the external space is provided, the elastic member deforms when the pressure in the internal space changes suddenly due to a sudden temperature change and cannot be eliminated only by ventilation of the communication hole. Therefore, it is possible to follow a sudden change in internal pressure and prevent damage to the diaphragm of the speaker. In addition, the elastic member can be reliably returned to the neutral position by the ventilation action of the communication hole. Therefore, even if a sudden temperature change occurs and the pressure in the internal space changes suddenly, the vibrating body can be prevented from being deformed or damaged, and the state can be quickly restored to a state in which normal sounding operation can be performed. Is possible.

The perspective view of the acoustic apparatus in embodiment of this invention seen from the front which is a sounding direction. The perspective view of the acoustic apparatus in embodiment of this invention seen from the rear side opposite to the sounding direction. An exploded perspective view of the audio apparatus shown in FIG. A side view of the audio apparatus shown in FIG. FIG. 4 is a cross-sectional view taken along the line AA of FIG. The cross-sectional view for demonstrating the problem which the sound apparatus of a comparative example has.

The audio device 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 6. In the following description, the sounding direction will be described as forward (Y1 direction), and the direction opposite to the sounding direction will be described as backward (Y2 direction). 1 to 6 show a center line O extending in the sounding direction.

The sound device 1 is for in-vehicle use, and is required not to be destroyed even when the car is flooded.
As shown in FIG. 3, the audio device 1 includes a main body case 2, a speaker unit 6, a circuit board 8, an elastic member 21, and a ventilation member 22.

As shown in FIG. 1, the main body case 2 is separated into a front case 3 and a rear case 4. The rear end portion of the front case 3 and the front end portion of the rear case 4 are fitted to each other, and the front case 3 and the rear case 4 are fixed to each other by the uneven fitting portions 5 provided at a plurality of places. The front case 3 and the rear case 4 are formed by resin molding using a synthetic resin material or die casting molding using a light metal material. A plurality of oblong holes 3a and a partition portion 3b for partitioning each oblong hole 3a are formed on the front portion of the front case 3 facing forward. As shown in FIGS. 2 and 5, an opening 4a is formed in the rear surface portion of the rear case 4 facing the rear (Y2 direction).

As shown in FIGS. 3 and 5, the speaker unit 6 is provided inside the front case 3. The speaker unit 6 includes a bracket 7 made of a non-magnetic or magnetic metal plate, and a bracket bending surface portion 7a formed on the outer diameter side of the bracket 7 is provided on the inner surface of the front case 3 with a speaker fixing screw 9 It is fixed with. As shown in FIG. 5, a bracket inner bottom portion 7b perpendicular to the center line O and a bracket outer bottom portion 7c are formed at the rear end portion of the bracket 7, and the bracket outer bottom portion 7c is forward (Y1) from the bracket inner bottom portion 7b. It is located in the direction).

As shown in FIG. 5, the magnetic circuit portion 10 is fixed to the rear surface of the inner bottom portion 7b of the bracket facing rearward (Y2 direction). The magnetic circuit unit 10 is composed of a yoke 12 to which the magnet 11 and the rear surface facing the rear (Y2 direction) of the magnet 11 are joined, and a plate 13 to which the front surface facing the front (Y1 direction) of the magnet 11 is joined. There is. The front surface of the plate 13 facing forward (Y1 direction) is adhered and fixed to the rear surface of the bracket 7 facing rearward (Y2 direction) of the inner bottom portion 7b of the bracket. The yoke 12 and the plate 13 are made of a magnetic material. A center pole portion 12a projecting forward (in the Y1 direction) is integrally formed in the central portion of the yoke 12. The magnet 11 and the plate 13 have a hollow cylindrical shape. A magnetic gap G is formed between the outer peripheral surface of the center pole portion 12a and the inner peripheral surface of the plate 13.

As shown in FIG. 5, the vibrating body 15 is provided in front of the magnetic circuit unit 10 (in the Y1 direction). The vibrating body 15 is composed of a diaphragm portion 16 and an edge portion 17. The flexural rigidity of the edge portion 17 with the axial direction of all virtual axes facing the plane perpendicular to the center line O as the curvature direction is lower than the flexural rigidity of the diaphragm portion 16 in the same direction. The edge portion 17 is made of urethane. The flexural rigidity is the product of the Young's modulus E and the moment of inertia of area I. The outer peripheral portion 16a of the diaphragm portion 16 is adhered to the edge portion 17. The outer end portion 17a of the edge portion 17 is adhered to and fixed to the bracket 7, and a joint portion (a) is formed. The edge portion 17 is adhered to and fixed to the diaphragm portion 16 to form a joint portion (b). The outer peripheral surface of the bobbin 18 is adhered and fixed to the inner peripheral portion 16b of the diaphragm portion 16 to form a joint portion (c). The diaphragm portion 16 of the vibrating body 15 has a cone shape, and has a tapered shape that inclines toward the rear (Y2 direction) toward the center line O.

As shown in FIG. 5, in the acoustic device 1, the main body case 2 is separated by the vibrating body 15 as a boundary, and the internal space A partitioned by the lower surface of the vibrating body 15 and the main body case 2 and the vibrating body 15 It is divided into a front space partitioned by the upper surface and the main body case 2 and an external space B which is a space outside the case.

As shown in FIG. 5, a damper 19 having a corrugated cross section is provided between the outer peripheral surface of the bobbin 18 and the outer bottom portion 7c of the bracket 7. Due to the elastic deformation of the edge portion 17 and the damper 19, the cone-shaped diaphragm portion 16 can vibrate in the front-rear direction (Y1-Y2 direction). A coil 20 is wound around the rear end of the bobbin 18 facing rearward, and the coil 20 is located in the magnetic gap G.

As shown in FIG. 3, the circuit board 8 on which the electronic components are mounted is fixed to the inside of the rear case 4 by using the circuit board fixing screws 14.

As shown in FIGS. 2 and 5, an opening 4a is formed in a rear surface portion of the rear case 4 facing the rear (Y2 direction), and an elastic member 21 for closing the opening 4a is provided. The peripheral edge portion 21b of the elastic member 21 is the rear surface of the rear case 4 and is adhered and fixed around the opening 4a. The elastic member 21 is made of an elastic material having rubber elasticity, that is, a natural rubber or a synthetic rubber material. The elastic member 21 is provided with a deformable raised portion 21c that rises toward at least one of an internal space A that is forward (Y1 direction) and an external space B that is rearward (Y2 direction) along the peripheral edge portion 21b. Has been done. As shown in FIG. 5, in the embodiment, the raised portion 21c is raised toward both the internal space A and the external space B.

The maximum amount of displacement that the elastic member 21 deforms forward (in the Y1 direction) with respect to the same pressure acting on the vibrating body 15 and the elastic member 21 toward the internal space A is that the vibrating plate portion 16 of the vibrating body 15 rearward ( It is configured to be larger than the maximum displacement amount that is displaced in the Y2 direction).

A communication hole 21a for communicating the internal space A and the external space B is provided at the position of the center of gravity of the elastic member 21. The communication hole 21a is closed with a ventilation member 22. The ventilation member 22 is so-called integrally molded or insert-molded with the elastic member 21, and the peripheral portion of the ventilation member 22 is embedded within the wall thickness of the elastic member 21. The ventilation member 22 is made of a waterproof and breathable material that allows air to pass through but does not allow water to pass through. The ventilation member 22 has a disk shape with the front-rear direction (Y1-Y2 direction) as the thickness direction.

Next, the sounding operation of the sound device 1 will be described.
When a current is applied to the coil 20, the vibrating body 15 vibrates in the front-rear direction (Y1-Y2 direction) due to the electromagnetic force excited by the magnetic field and the current acting on the coil 20 in the magnetic circuit unit 10, and the sound pressure is generated. It is given in front of the sounding direction (Y1 direction).

In normal use, in the acoustic device 1, the air in the internal space A and the air in the external space B can freely move in each other's space through the communication hole 21a and the ventilation member 22, so that the air in the internal space A can move freely. It is possible to make the pressure of the air and the air pressure of the external space B the same. Therefore, the vibrating body 15 is less likely to receive a pressure change in the internal space A, and the sound quality is stable.

However, since the sound device 1 is mounted on a car, the temperature may drop sharply after being placed in a high temperature air environment and then being submerged in low temperature water. At that time, in the sound device 1, the pressure in the internal space A decreases, and the air in the internal space A tends to contract.

When the internal pressure of the internal space A drops sharply, the elastic member 21 deforms forward (Y1 direction) from the neutral state (v) toward the inside of the internal space A, and is in the retracted state (vi) shown by the broken line in FIG. ). Since the elastic member 21 is provided with a deformable raised portion 21c that rises toward each of the internal space A and the external space B along the shape of the opening 4a of the rear case 4. The elastic member 21 is easily deformed. Further, the elastic member 21 is deformed to the front (Y1 direction) more than the vibrating body 15 of the speaker unit 6 is displaced to the rear (Y2 direction). When the elastic member 21 is in the retracted state (vi), the volume of the internal space A is reduced, and the decrease in the pressure in the internal space A is suppressed.

Therefore, even if the pressure in the internal space A drops sharply, the amount of movement of the diaphragm portion 16 of the vibrating body 15 backward (in the Y2 direction) from the neutral state (vii) to the retracted state (vii) becomes small. Peeling of the joint portion (a) between the outer end portion 17a of the edge portion 17 and the bracket 7, peeling of the joint portion (b) between the diaphragm portion 16 and the edge portion 17, and joining of the diaphragm portion 16 and the bobbin 18. Peeling of the part (c) is less likely to occur. In addition, the diaphragm portion 16 and the edge portion 17 are less likely to be destroyed.

Further, for example, even if the inundation of the acoustic device 1 is released and the ambient temperature begins to rise, the rise in the temperature of the air in the internal space A of the acoustic device 1 is delayed, and the internal space A and the external space B become The pressure difference may not be resolved immediately. Even in such a case, since air can flow between the internal space A and the external space B through the communication hole 21a and the ventilation member 22, the elastic member 21 changes from the retracted state (vi) to the neutral state (v). Along with being quickly pulled back, the vibrating plate portion 16 of the vibrating body 15 is also quickly pulled back from the retracted state (viii) to the neutral state (vii), and the reduced volume of the internal space A returns to the original volume. Therefore, the diaphragm portion 16 of the vibrating body 15 is held at a position deviated from the neutral state (vii), and the volume of the internal space A is reduced from the normal state, resulting in deterioration of acoustic performance. It recovers and can perform normal pronunciation operation.

The communication hole 21a is provided at the position of the center of gravity of the elastic member 21. As a result, a space can be secured by providing the communication hole 21a and the elastic member 21 at different positions. For example, the elastic member 21 can be made larger.
Since the communication hole 21a through which air passes is located at the center of the elastic member 21 that is easily deformed, even if the pressure in the internal space A drops sharply, a large load is applied to the fixed portion between the ventilation member 22 and the elastic member 21. It is possible to prevent the ventilation member 22 from coming off from the elastic member 21.

The communication hole 21a is located at the center of gravity of the elastic member 21, that is, the communication hole 21a is located at the center of the elastic member 21 formed along the edge of the opening 4a. When the elastic member 21 is deformed, air passes through the communication hole 21a at the center of the elastic member 21, so that the elastic member 21 is deformed symmetrically without biased deformation. When the temperature returns and the elastic member 21 tries to recover by its own elastic force, the communication hole 21a at the center allows the elastic member 21 to recover quickly in a well-balanced manner.

As a comparative example, FIG. 6 shows an acoustic device 1 without an elastic member 21, a communication hole 21a, and a ventilation member 22. In this comparative example, when a sudden pressure drop occurs in the air in the internal space A, the edge portion 17 having low rigidity is sucked from the neutral state (i) to the rear (Y2 direction) toward the internal space A. It becomes the inverted state (ii). Following the inversion of the edge portion 17, the diaphragm portion 16 is in a deformed state (iii) bent toward the internal space A. When it is pulled strongly backward due to a decrease in internal pressure in the bent deformed state (iii), the joint portion (a) between the outer end portion 17a of the edge portion 17 and the bracket 7 is peeled off, and the diaphragm portion 16 and the edge portion are peeled off. Peeling of the joint portion (b) with 17 and the joint portion (c) between the diaphragm portion 16 and the bobbin 18 is likely to occur.

In the embodiment shown in FIG. 5, when a sudden pressure drop occurs in the air in the internal space A, the elastic member 21 is pulled forward (in the Y1 direction) and changes from the neutral state (v) to the pulled state (vi). As a result, as shown in FIG. 6, it is possible to prevent the diaphragm portion 16 from being bent and deformed (iii), and the joint portion (a) between the outer end portion 17a of the edge portion 17 and the bracket 7 vibrates. It becomes easy to prevent peeling of the joint portion (b) between the plate portion 16 and the edge portion 17 and the joint portion (c) between the diaphragm portion 16 and the bobbin 18, and it is possible to prevent the diaphragm portion 16 and the edge portion 17 from being destroyed. .. Further, by sucking air from the external space B into the internal space A through the ventilation member 22 provided in the communication hole 21a, the elastic member 21 is returned from the retracted state (vi) to the neutral state (v) and vibrates. The plate portion 16 is returned from the retracted state (viii) to the neutral state (vii), the volume of the internal space A is returned to the normal state, and it is possible to quickly restore the state so that the normal sounding operation can be performed. Become.

1 Sound device 2 Main body case 3 Front case 3a Long square hole 3b Partition 4 Rear case 5 Concavo-convex fitting part 6 Speaker unit 7 Bracket 7a Bracket bending surface 7b Bracket inner bottom 7c Bracket outer bottom 9 Speaker fixing screw 10 Magnetic circuit 11 Magnet 12 York 13 Plate 14 Circuit board fixing screw 15 Vibrating body 16 Diaphragm part 17 Edge part 18 Bobbin 19 Damper 20 Coil 21 Elastic member 21a Communication hole 21b Peripheral part 21c Raised part 22 Ventilation member A Internal space B External space G Magnetic gap O center line

Claims (6)

A main body case and a speaker unit fixed in the main body case are provided.
The speaker unit is an acoustic device having a magnetic circuit unit including a magnet, a coil on which a magnetic field generated in the magnetic circuit unit acts, and a vibrating body vibrating together with the coil.
The internal space and the external space of the main body case are partitioned by the vibrating body as a boundary.
An elastic member whose one surface is in contact with the internal space and the other surface is in contact with the external space and is deformed by the difference in pressure acting on both sides.
It is characterized by including a communication hole that communicates the internal space and the external space, and a ventilation member that is provided so as to cover the communication hole to allow the passage of air and block the passage of fluid. Sound device. The acoustic device according to claim 1, wherein the communication hole is provided in the elastic member. The acoustic device according to claim 2, wherein the position where the communication hole is provided is the position of the center of gravity of the elastic member. Claim 1 is characterized in that the maximum displacement amount of the elastic member is larger than the maximum displacement amount of the vibrating body with respect to the same pressure acting on the vibrating body and the internal space acting on the elastic member. The acoustic device according to any one of 3. The peripheral edge portion of the elastic member is fixed to the main body case, and the elastic member has a deformable ridge portion that bulges toward at least one of the internal space and the external space along the peripheral edge portion. The acoustic device according to any one of claims 1 to 4, which is provided. The acoustic device according to any one of claims 1 to 5, wherein the elastic member is made of rubber.

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