JP7258690B2 - sound equipment - Google Patents

Description

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

In general, audio devices such as warning sound speakers and bathroom speakers mounted in cars need to prevent water from entering the internal structure of the device, so the main body case is required to be watertight. However, this type of audio equipment may be immersed 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, pulling the diaphragm inward or, conversely, pushing it out, causing deformation or damage to the diaphragm. There is a risk that it will be lost.

Therefore, an acoustic device described in Patent Document 1 below has an internal space defined inside the device, a speaker provided at a boundary portion inside the device, and a diaphragm sealing the internal space. Also, a diaphragm cover that covers the diaphragm is formed with a ventilation hole that communicates with the external space. When the pressure in the internal space changes due to a change in temperature, the diaphragm operates to prevent deformation and damage to 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-like member, and this 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. In addition, even if the environmental temperature stabilizes after the pressure in the internal space changes, there is no means for assimilating the pressure in the internal space and the pressure in the external space, so the pressure change in the internal space tends to remain. Therefore, the state where the paper cone portion of the speaker is displaced by the pressure tends to continue.

As a result, the paper cone portion of the speaker is pulled into and pushed out into the body case, and held at a position deviated from the normal neutral position. Further, if 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 of being changed from the normal value. If sound generation is performed in such a state, the acoustic characteristics of the sound generation frequency band are changed, and there is a possibility that the acoustic characteristics may deteriorate more than usual.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems. An object of the present invention is to provide an acoustic device having a structure capable of preventing excessive displacement, preventing deformation and breaking of a vibrating body, and realizing stable sounding operation.

According to 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 section including a magnet and a coil on which a magnetic field generated by the magnetic circuit section acts. , and a vibrating body that vibrates together with the coil,
With the vibrating body as a boundary, the internal space and the external space of the main body case are separated, one surface is in contact with the internal space and the other surface is in contact with the external space. a deformable elastic member; a communication hole communicating between the internal space and the external space; It is characterized by

It is preferable that the communication hole is provided in the elastic member.

It is preferable that the position where the communication hole is provided is the center of gravity of the elastic member.

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

A peripheral edge portion of the elastic member is fixed to the main body case, and the elastic member has a deformable protruding portion that protrudes toward at least one of the internal space and the external space along the peripheral edge portion. is preferably provided.

Preferably, the elastic member is made of rubber.

Since the acoustic device of the present invention is provided with a communication hole that communicates the internal space and the external space, the air in the internal space and the air in the external space can freely move between the spaces, and the sound in a normal environment can be maintained. It is possible not to cause pressure fluctuations in the internal space due to temperature changes. Therefore, it is possible to always prevent the influence of the temperature change on the sound quality, for example, the fluctuation of the acoustic characteristics of the sounding frequency band. Furthermore, since an elastic member is provided to separate the internal space from the external space, the elastic member is deformed when the pressure in the internal space changes rapidly due to a sudden temperature change and cannot be eliminated only by ventilating the communication holes. This makes it possible to follow sudden changes 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 effect of the communication hole. Therefore, even if a sudden temperature change occurs and the pressure in the internal space changes abruptly, the vibrating body can be prevented from being deformed or damaged, and the vibrating body can be quickly restored to a state in which normal sound generation can be performed. is possible.

1 is a perspective view of an audio device according to an embodiment of the present invention as viewed from the front, which is the sounding direction; FIG. FIG. 2 is a perspective view of the acoustic device according to the embodiment of the present invention as seen from the rear opposite to the direction of sound generation. FIG. 2 is an exploded perspective view of the acoustic device shown in FIG. 1; FIG. 2 is a side view of the acoustic device shown in FIG. 1; FIG. 5 is a cross-sectional view taken along line AA of FIG. 4; Sectional drawing for demonstrating the subject which the acoustic device of a comparative example has.

An acoustic device 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. In the following description, the sounding direction is defined as the front (Y1 direction), and the direction opposite to the sounding direction is defined as the rear (Y2 direction). 1 to 6 show a center line O extending in the direction of sound generation.

The acoustic 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 acoustic 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.

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

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

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

As shown in FIG. 5, a vibrating body 15 is provided in front of the magnetic circuit section 10 (Y1 direction). The vibrating body 15 is composed of a diaphragm portion 16 and an edge portion 17 . The edge portion 17 has a lower bending rigidity than the diaphragm portion 16 in the same direction, with the axial directions of all imaginary axes facing the plane perpendicular to the center line O being the curvature directions. The edge portion 17 is made of urethane. The bending stiffness is the product of the longitudinal elastic modulus E and the area moment of inertia I. An outer peripheral portion 16 a of the diaphragm portion 16 is adhered to the edge portion 17 . An outer end portion 17a of the edge portion 17 is adhered and fixed to the bracket 7 to form a joint portion (a). The edge portion 17 is adhered 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 vibrating plate portion 16 of the vibrating body 15 has a cone shape, and has a tapered shape that is inclined rearward (Y2 direction) toward the center line O. As shown in FIG.

As shown in FIG. 5, in the acoustic device 1, the body case 2 is separated by the vibrating body 15 as a boundary. It is divided into a front space defined 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, between the outer peripheral surface of the bobbin 18 and the bracket outer bottom portion 7c of the bracket 7, a damper 19 having a corrugated cross section is provided. The elastic deformation of the edge portion 17 and the damper 19 allows the cone-shaped diaphragm portion 16 to vibrate in the front-rear direction (Y1-Y2 direction). A coil 20 is wound on the rearwardly facing rear end of the bobbin 18, and the coil 20 is positioned within the magnetic gap G. As shown in FIG.

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

As shown in FIGS. 2 and 5, an opening 4a is formed in the rear face portion of the rear case 4 facing rearward (Y2 direction), and an elastic member 21 is provided to close the opening 4a. A peripheral edge portion 21b of the elastic member 21 is adhered and fixed to the rear surface of the rear case 4 around the opening portion 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 protrusion 21c that protrudes toward at least one of the inner space A that is the front (Y1 direction) and the outer space B that is the rear (Y2 direction) along the peripheral edge 21b. It is 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. As shown in FIG.

With respect to the same pressure acting on the vibrating body 15 and the elastic member 21 toward the internal space A, the maximum amount of displacement in which the elastic member 21 deforms forward (Y1 direction) is that the diaphragm portion 16 of the vibrating body 15 moves backward ( Y2 direction) is configured to be greater than the maximum displacement amount.

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

Next, the sounding operation of the audio 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 current and the magnetic field acting on the coil 20 in the magnetic circuit section 10, and the sound pressure increases. It is given forward in the sounding direction (Y1 direction).

During normal use, the acoustic device 1 allows the air in the internal space A and the air in the external space B to freely move through each other through the communication hole 21a and the ventilation member 22. Therefore, the air in the internal space A and the pressure of the air in the outer space B can be made the same. Therefore, the vibrating body 15 is less susceptible to pressure changes in the internal space A, and the sound quality is stabilized.

However, since the audio device 1 is mounted in a vehicle, the temperature may drop rapidly after being placed in a high-temperature air environment, such as by being submerged in low-temperature water. At that time, the pressure in the internal space A of the acoustic device 1 decreases, and the air in the internal space A tries to contract.

When the internal pressure of the internal space A drops rapidly, the elastic member 21 deforms forward (Y1 direction) toward the inside of the internal space A from the neutral state (v), and the retracted state (vi ). Since the elastic member 21 is provided with a deformable protrusion 21c that protrudes toward 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 deforms forward (Y1 direction) more than the vibrating body 15 of the speaker unit 6 is displaced backward (Y2 direction). When the elastic member 21 is in the retracted state (vi), the volume of the internal space A is reduced, and the pressure drop in the internal space A is suppressed.

Therefore, even if the pressure in the internal space A suddenly drops, the movement amount of the diaphragm portion 16 of the vibrating body 15 moving backward (in the Y2 direction) from the neutral state (vii) to the retracted state (viii) becomes small. Separation of joint (a) between outer end 17a of edge 17 and bracket 7, separation of joint (b) between diaphragm 16 and edge 17, and joint between diaphragm 16 and bobbin 18 Part (c) is less likely to peel off. In addition, breakage of diaphragm portion 16 and edge portion 17 is less likely to occur.

Further, for example, even if the sound device 1 is no longer flooded and the ambient temperature begins to rise, the rise in the temperature of the air in the internal space A of the sound device 1 is delayed, and the temperature rise between the internal space A and the external space B is delayed. The pressure difference may not be eliminated immediately. Even in such a case, since air can flow between the internal space A and the external space B via the communication hole 21a and the ventilation member 22, the elastic member 21 changes from the retracted state (vi) to the neutral state (v). As it is quickly pulled back, the diaphragm 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 its original volume. Therefore, the deterioration of the acoustic performance due to the diaphragm portion 16 of the vibrating body 15 being held at a position deviated from the neutral state (vii) and the volume of the internal space A being reduced from the normal state can be prevented quickly. It is possible to recover and perform normal sounding operations.

The communication hole 21 a is provided at the center of gravity of the elastic member 21 . Thereby, a space can be ensured rather than providing the communicating 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 the air passes is located at the center of the easily deformable elastic member 21, even if the pressure in the internal space A suddenly drops, a large load is applied to the fixing portion between the ventilation member 22 and the elastic member 21. Therefore, it is possible to prevent the ventilation member 22 from coming off from the elastic member 21. - 特許庁

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 in 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 return by its own elastic force, the communicating hole 21a in the center enables a quick return with good balance.

As a comparative example, FIG. 6 shows the acoustic device 1 without the elastic member 21, the communication hole 21a and the ventilation member 22. As shown in FIG. In this comparative example, when a sudden pressure drop occurs in the air in the internal space A, the edge portion 17 with low rigidity is sucked rearward (in the Y2 direction) from the neutral state (i) and directed toward the internal space A. It becomes inversion state (ii). Following the reversal of the edge portion 17, the diaphragm portion 16 is bent toward the internal space A to enter the deformed state (iii). In the deformed state (iii) in which the bracket 7 is bent, if it is strongly pulled backward due to a decrease in the internal pressure, the joint (a) between the outer end 17a of the edge portion 17 and the bracket 7 may peel off, or the diaphragm portion 16 and the edge portion may peel off. 17 and the joint portion (c) between the diaphragm portion 16 and the bobbin 18 are also likely to come off.

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), shifting from the neutral state (v) to the retracted state (vi). As a result, it is possible to prevent the diaphragm portion 16 from being bent and deformed (iii) as shown in FIG. Separation 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 can be easily prevented, and breakage of the diaphragm portion 16 and the edge portion 17 can be prevented. . In addition, 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 normal, and the normal sounding operation can be quickly restored. Become.

1 Acoustic Device 2 Body Case 3 Front Case 3a Long Angle Hole 3b Partition Part 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 Part 11 Magnet 12 Yoke 13 Plate 14 Circuit board fixing screw 15 Vibrating body 16 Diaphragm portion 17 Edge portion 18 Bobbin 19 Damper 20 Coil 21 Elastic member 21a Communication hole 21b Peripheral edge portion 21c Raised portion 22 Ventilation member A Internal space B External space G Magnetic gap O Center line

Claims (6)

A body case and a speaker unit fixed in the body case are provided,
An acoustic device in which the speaker unit includes a magnetic circuit section including a magnet, a coil on which a magnetic field generated by the magnetic circuit section acts, and a vibrating body that vibrates together with the coil,
With the vibrating body as a boundary, an internal space and an external space of the main body case are separated,
an elastic member that has one surface in contact with the internal space and the other surface in contact with the external space, and deforms due to the difference in pressure acting on both surfaces;
A communication hole communicating between the internal space and the external space; and a ventilation member provided covering the communication hole to allow passage of air and block passage of fluid. sound device. 2. The acoustic device according to claim 1, wherein the communication hole is provided in the elastic member. 3. 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. 2. The maximum amount of displacement of the elastic member is larger than the maximum amount of displacement of the vibrating body with respect to the same pressure acting on the vibrating body and the elastic member toward the internal space. 4. The acoustic device according to any one of 1 to 3. A peripheral edge portion of the elastic member is fixed to the main body case, and the elastic member has a deformable protruding portion that protrudes toward at least one of the internal space and the external space along the peripheral edge portion. 5. An acoustic device according to any one of claims 1 to 4. 6. The acoustic device according to claim 1, wherein said elastic member is made of rubber.

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