JP2012070187A - Speaker device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speaker device that is compact and is capable of producing a large volume.SOLUTION: The speaker device includes: a piezoelectric plate 11 that vibrates on voltage application; a diaphragm 12 that has a bulge 121 bulging forward into a substantial dome and a flange 122 formed on a circumferential edge of the bulge 121 and has a recess 123 behind the bulge 121 closed by the piezoelectric plate 11 so as to vibrate and generate a sound when the vibration of the piezoelectric plate 11 is transmitted; and a housing 13 that has a fitting projection 142 and a fitting groove 152 for fixing the flange 122 of the diaphragm 12 when fitted together, and confronts the front surface of the diaphragm 12 via a front cavity 143. The housing 13 is provided with openings 14b in a bottom surface 14a confronting the front surface of the diaphragm 12, and the opening 14b are covered with mesh parts 161 of a protective member 16. The front cavity 143 and the openings 14b form a Helmholtz resonator 17.

Description

  The present invention relates to a speaker device.

  Conventionally, as shown in FIG. 7, a speaker device including a horn 103 for increasing sound pressure has been provided (see, for example, Patent Document 1).

  The speaker device includes a plate-like diaphragm 101 that vibrates and emits sound when a voltage is applied thereto, a housing 102 that houses and fixes the diaphragm 101, and a sound that is assembled to the housing 102 and emitted from the diaphragm 101. And a horn 103 for increasing the sound pressure.

  The speaker device is used, for example, as a vehicle-mounted speaker device such as a vehicle anti-theft device. When an abnormality or the like occurs in the vehicle, a loud alarm sound is generated around the vehicle to notify the abnormality.

  Here, many of in-vehicle speaker devices are often arranged in a limited space in a vehicle such as an engine room or a tire house, so that downsizing has been desired.

Japanese Patent Laid-Open No. 9-307985

  However, in general, when the size of the speaker device is reduced, the size of the diaphragm is also reduced and the sound emitted from the speaker device is also reduced. Therefore, it is difficult to reduce the size of the speaker device while maintaining the sound volume.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a speaker device that can be miniaturized while maintaining sound pressure.

  In order to solve the above-described problems, a speaker device of the present invention includes a piezoelectric plate that vibrates when a voltage is applied thereto, a bulging portion that bulges to one side and is formed in a substantially dome shape, and the bulging portion of the bulging portion. It has a flange portion formed on the periphery, and the piezoelectric plate is covered in a recess formed on the other surface side of the bulging portion, and vibrations are generated by transmitting vibrations of the piezoelectric plate to generate sound. A diaphragm; and a housing having a fixing means for fixing a collar portion of the diaphragm, and opposed to one surface of the diaphragm via a space, and the housing is disposed on a surface facing the one surface of the diaphragm. An opening is formed, a mesh member is covered in the opening, and a resonance part is formed from the space and the opening.

  In the speaker device, it is preferable that the piezoelectric plate is made of piezoelectric ceramics, and the diaphragm is made of aluminum.

  In the speaker device, it is preferable that the opening is formed to face a peripheral edge of the bulging portion on a surface of the housing facing the one surface of the diaphragm.

  In this speaker device, it is preferable that the housing is formed with a drain hole.

  In the speaker device, it is preferable that the drain hole is formed continuously with the opening.

  As described above, the present invention has an effect that it is possible to provide a speaker device that can be miniaturized while maintaining sound pressure.

1 is a cross-sectional view of a speaker device according to an embodiment of the present invention. The perspective view of the speaker apparatus in the same as the above is shown. The four views of the speaker device are shown. Sectional drawing of the speaker apparatus in the same as the above is shown. The front view of the protection member with which the speaker apparatus in the same as the above is provided is shown. The principal part enlarged view of the protection member in the same as the above is shown. Sectional drawing of the speaker apparatus in a prior art example is shown. The relationship diagram of sound pressure is shown.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
The speaker device in the present embodiment will be described with reference to FIGS. In the following description, the vertical direction in FIG.

  As shown in FIG. 1, the speaker device according to this embodiment includes a sound generation unit 1 including a piezoelectric plate 11, a circuit block 2 that applies a voltage signal to the piezoelectric plate 11 and vibrates the piezoelectric plate 11, and a circuit block 2. And a housing cover 3 for storing the housing.

  The sound generation unit 1 includes a piezoelectric plate 11, a vibration plate 12 bonded to the piezoelectric plate, a housing 13 that houses the piezoelectric plate 11 and the vibration plate 12, and a protective member 16 that is fixed to the housing 13. .

  The piezoelectric plate 11 is formed in a substantially disc shape by piezoelectric ceramics, and electrodes (not shown) are provided on both surfaces thereof. In addition, since the piezoelectric plate 11 is formed of piezoelectric ceramics, it has low temperature dependency and vibrates stably even when the speaker device is disposed at a high temperature location such as an engine room. For this reason, the speaker device can stably generate sound.

The diaphragm 12 is made of, for example, a material having a large specific rigidity, such as aluminum, and a bulging portion 121 that bulges to the front side and is formed in a substantially dome shape, and an annular ridge formed on the periphery of the bulging portion 121. The unit 122 is configured. Here, since the diaphragm 12 is made of aluminum which is a material having a large specific rigidity, a larger sound pressure can be obtained when the diaphragm 12 is vibrated, and the diaphragm 12 can be easily processed. The diaphragm 12 is covered with the piezoelectric plate 11 at the opening of the concave portion 123 formed on the rear surface side of the bulging portion 121, and the peripheral edge portion of the piezoelectric plate 11 is bonded to the opening peripheral edge of the concave portion 123.

  In addition, a substantially annular curved portion 122 a that curves rearward over the entire circumference of the flange 122 is formed at a substantially central portion in the radial direction (width direction) of the flange 122.

  The housing 13 includes a case main body 14 provided on the front side of the diaphragm 12 and a lid member 15 provided on the rear side of the diaphragm 12 (piezoelectric plate 11).

  The case main body 14 is formed in a substantially cylindrical shape with an open rear surface. A stepped portion 141 is formed on the inner peripheral surface of the case main body 14 at the approximate center in the axial direction (front-rear direction), and the rear side is the front side. The diameter is expanded compared to. In addition, a fitting protrusion 142 that protrudes rearward is formed from substantially the center in the radial direction of the stepped portion 141.

  The lid member 15 is formed in a substantially disk shape, and an annular protrusion 151 that protrudes forward is formed from the peripheral edge thereof. In addition, the protrusion 151 is formed with a fitting groove 152 into which the fitting protrusion 142 is fitted substantially in the center in the radial direction. And when the fitting projection 142 of the housing 13 and the fitting groove 152 of the lid member 15 are fitted, the tip of the flange 122 is sandwiched between the step 141 and the projection 151, The diaphragm 12 is fixed. That is, the stepped portion 141 and the protruding portion 151 serve as a fixing means for the diaphragm 12. The front surface of the diaphragm 12 faces the bottom surface 14 a of the case main body 14 via the space 143 in the case main body 14. Here, the space 143 forms a front cavity. Hereinafter, the space 143 is referred to as a front cavity 143.

  Further, as shown in FIG. 2, the bottom surface 14a of the case main body 14 has a plurality of substantially arc-shaped openings 14b along the periphery in the vicinity of the periphery of the bottom surface 14a at equal intervals along the circumferential direction ( In this embodiment, four) are formed. Here, the opening 14 b is formed to face the periphery of the bulging portion 122 of the diaphragm 12.

  Further, on the bottom surface 14a of the case main body 14, a substantially triangular drain hole 14c is formed at a lower end when the speaker device is assembled to a vehicle or the like. Here, the drain hole 14c is formed continuously from the opening 14b, and is formed from the outer edge of the opening 14b to the periphery of the bottom surface 14a. In the present embodiment, the drain hole 14c has a substantially triangular shape, but the shape of the drain hole 14c is not limited to this, and may be another shape such as a semicircular shape. In addition, a disk-shaped caulking protrusion 14d for fixing the protection member 16 is formed on the bottom surface 14a.

  The protection member 16 is formed in a substantially annular shape from stainless steel, and a plurality (four in the present embodiment) of arc-shaped mesh portions (mesh members) 161 are formed at substantially equal intervals along the outer periphery. Here, the mesh part 161 is configured by forming a plurality of rectangular through holes 16a in a lattice shape by etching or the like, as shown in FIG. 6A. The shape of the through hole 16a may be a square as shown in FIG.

  Further, the protective member 16 is formed with a caulking hole 16b, and the caulking projection 14c of the case main body portion 14 is inserted into the caulking hole 16b and caulked so that the protective member 16 is fixed to the case main body portion 14. Is done. Further, at that time, each mesh portion 16 a of the protection member 16 is covered with the opening portion 14 b so as to face each opening portion 14 b of the case main body portion 14. Thereby, it can prevent that a foreign material penetrate | invades into the front cavity 143 via the opening part 14b, and can prevent malfunctions, such as the diaphragm 12 being damaged.

  The circuit block 2 includes a circuit board 21 on which a drive circuit including a transformer 21a is mounted, and a secondary battery 22 arranged in parallel with the transformer 21a. The circuit block 2 is disposed behind the sound generation unit 1.

  As shown in FIG. 1, the circuit board 21 is disposed behind the lid member 15 substantially in parallel with the lid member 15 and is connected to an electrode of the piezoelectric plate 11 via a wiring (not shown). Here, the said wiring penetrates the penetration hole 15a formed in the cover member 15 (refer FIG. 4).

  Then, the drive circuit mounted on the circuit board 21 converts the DC power supplied from the secondary battery 22 into desired drive power using the transformer 21a, and the drive power is transferred to the piezoelectric plate 11 via the wiring. Output.

  The housing cover 3 is formed in a substantially bottomed cylindrical shape with an open front surface, and as shown in FIG. 4, the depth dimension on one side in the radial direction (right side in FIG. 4) is the other side (left side in FIG. 4). It is formed larger than the depth dimension. Hereinafter, one side in the radial direction of the housing cover 3 is referred to as a component storage portion 3a, and the other side in the radial direction is referred to as a connector forming portion 3b. The housing cover 3 has a substantially cylindrical connector portion 31 erected on the outer surface (rear surface) of the connector forming portion 3b.

  Further, in the connector portion 31, a connector terminal 23 is provided which is inserted through the housing cover 3 and has one end soldered to the through hole 21 b of the circuit board 21. The other end of the connector terminal 23 protrudes into the connector portion 31 and is electrically connected to a plug terminal of a plug connector (not shown) inserted and connected to the connector portion 31.

  In addition, three support protrusions 32 project forward from the bottom surface of the housing cover 3 on the component storage portion 3a side. Here, the three support protrusions 32 are formed with locking portions 32a projecting inwardly at the tip portions, and two of the three support members 32 are formed to face each other to form a circuit board. The circuit board 21 is sandwiched by coming into contact with the side edges of the circuit board 21, and the locking parts 32 a of the support members 32 are brought into contact with the front surface of the circuit board 21 to support the circuit board 21. Further, the remaining one support member 32 supports the circuit board 21 by abutting against the side edge of the circuit board 21 on one side in a direction orthogonal to the facing direction of the pair of support members 32 facing each other. . That is, the circuit block 2 is supported by the three support members 32 and stored in the housing cover 3.

  The sound generating unit 1, the circuit block 2, and the housing cover 3 are integrally provided by fitting and connecting the opening periphery of the housing cover 3 to the opening periphery of the housing 13.

  2 and 3, the outer peripheral surface of the housing 13 has a plurality of (four in this embodiment) outer peripheral bracket connection portions 131 each having a substantially L-shaped cross section with a notch 131a formed at the tip. It is formed at substantially equal intervals along the surface. On the other hand, a substantially L-shaped bracket (not shown) is attached to the vehicle body to which the speaker device is attached, and the bracket device and the bracket connecting portion 131 are fastened together with screws (not shown), so that the speaker device is attached to the vehicle body. Fixed.

  A plug connector (not shown) is inserted and connected to the connector portion 31, and a notification signal input from an external device or the like via the plug connector is input to the circuit board 21 via the connector terminal 23. When the notification signal is input, the circuit board 21 outputs driving power (voltage signal) to the piezoelectric plate 11, and the piezoelectric plate 11 to which the driving power is input vibrates. Subsequently, the vibration of the piezoelectric plate 11 is transmitted to the vibration plate 12, and the vibration plate 12 is also vibrated and a sound is emitted from the vibration plate 12.

  The diaphragm 12 provided in the speaker device of the present embodiment having the above-described configuration is compared with the flat plate-like diaphragm 101 provided in the conventional speaker device shown in FIG. 7 because the dome-shaped bulging portion 122 vibrates. The amplitude is large. Furthermore, the sound emitted by the vibration of the diaphragm 12 (the bulging part 122) passes through the front cavity 143 and is emitted to the outside through the opening part 14b. Here, a Helmholtz resonator (resonance part) 17 is formed by the front cavity 143 and the opening 14b, and the sound pressure of the fundamental frequency is efficiently generated by the Helmholtz resonator 17 from the sound emitted from the diaphragm 11. It is raised and emitted to the outside. Therefore, since the sound pressure is efficiently increased by the diaphragm 12 having the substantially dome-shaped bulging portion 122 and the Helmholtz resonator 17 in the speaker device of this embodiment, sufficient sound pressure is ensured without providing a horn. can do.

  In addition, since it is not necessary to provide a horn on the front side of the housing 13, the number of parts can be reduced, and the height dimension (dimension in the front-rear direction) can be suppressed, and the size can be reduced. .

  Further, since there is no horn, horn design (setting of the cut-off frequency in the horn) is not necessary.

  Furthermore, since the sound emitted from the diaphragm 12 is directly emitted to the outside via the Helmholtz resonator 17 without going through the horn, the directivity can be made flat.

  Further, in the present embodiment, since the opening 14b is formed so as to oppose the peripheral edge of the bulging portion 122 in the diaphragm 12, the sound pressure is compared with the case where the opening 14b is formed at the center of the bottom surface 14a. Can be increased.

  Further, the vibration plate 12 has a distal end portion of the flange portion 122 fixed to the housing 13, and since the curved portion 122 a is formed between the distal end portion and the bulging portion 121, the bulging portion 121. Can be prevented from being attenuated at the holding portion (the tip portion). That is, the decrease in sound pressure can be suppressed by forming the curved portion 122a.

  In addition, since the curved portion 122a is formed, it is possible to suppress the occurrence of rolling in the diaphragm 12 due to vibration generated when the speaker device is provided in, for example, a vehicle. It can be vibrated and the sound pressure can be improved.

  Moreover, in the speaker apparatus of this embodiment, since the drain hole 14c is continuously formed in the opening 14b formed in the periphery of the bottom face 14a, it can drain easily. Moreover, since the drain hole 14c is continuously formed in the opening part 14b, the opening part 14b can also be used as a part of the drain hole 14c, and can drain water more efficiently.

  Further, since the conventional speaker device is not provided with a water drain hole, a packing for preventing water from entering the housing 102 is necessary. However, since the speaker device of the present embodiment has the drain hole 14c, the packing is not necessary, and the number of parts can be reduced.

  Further, the protection member 16 included in the speaker device of the present embodiment is made of a stainless steel plate, and the mesh portion 161 is formed by etching or the like. Therefore, for example, the strength of the mesh portion 161 can be increased as compared with the case where the mesh portion 161 is formed by braiding a metal wire. Here, when performing an inspection relating to conformity to the IP standard, the inspection is performed by inserting a wire having a predetermined thickness (diameter) into the mesh portion 161. And conventionally, since the mesh part 161 was formed by knitting a metal wire, for example, there was a problem that the mesh part 161 was loosened when the wire was inserted. However, since the mesh part 161 provided in the speaker device of the present embodiment has a higher strength than that formed by braiding a metal wire, it prevents problems such as the mesh part 161 being loosened when a wire is inserted. The diaphragm 12 can be reliably protected.

  Further, when the mesh portion 161 is formed by braiding a metal wire, the shape of the mesh portion 161 is limited because the wire is easily loosened at the peripheral portion of the mesh portion 161. However, in the mesh part 161 of this embodiment, since the mesh part 161 is formed on a stainless steel plate by etching or the like, the shape of the mesh part 161 is not limited. Therefore, the shape of the mesh portion 161 can be changed to a shape necessary for obtaining desired acoustic characteristics.

  Further, since the through hole 16a in the mesh portion 161 is rectangular, for example, the aperture ratio of the mesh portion 161 can be increased as compared with the case where the through hole 16a is circular, and the inside of the front cavity 143 can be increased from the outside. Can be pronounced efficiently.

  Furthermore, since the through holes 16a of the mesh portion 161 are formed by etching, the hole pitch of the through holes 16a can be narrowed compared to the case where the mesh portion 161 is formed by braiding a metal wire. Therefore, the aperture ratio of the mesh part 161 can be further increased, and sound can be generated more efficiently.

DESCRIPTION OF SYMBOLS 11 Piezoelectric plate 12 Diaphragm 13 Housing 14 Case main-body part 14b Opening part 14c Drain hole 15 Lid member 16 Protective member 121 Bumping part 122 Gutter part 143 Front cavity (space)
161 Mesh part (mesh member)
17 Helmholtz resonator (resonance unit)

Claims (5)

A piezoelectric plate that vibrates when a voltage is applied;
It has a bulging portion that bulges to one surface side and is formed in a substantially dome shape, and a flange portion that is formed on the periphery of the bulging portion, and the piezoelectric element is formed in a recess formed on the other surface side of the bulging portion A vibration plate that is oscillated and generates sound by transmitting vibrations of the piezoelectric plate covered with the plate;
A fixing means for fixing the flange portion of the diaphragm, and a housing facing one surface of the diaphragm via a space;
The housing has an opening formed on a surface facing one surface of the diaphragm, and the opening is covered with a mesh member.
A speaker device, wherein a resonance portion is formed from the space and the opening.   The speaker device according to claim 1, wherein the piezoelectric plate is made of piezoelectric ceramics, and the diaphragm is made of aluminum.   3. The speaker device according to claim 1, wherein the opening is formed to face a peripheral edge of the bulging portion on a surface of the housing facing the one surface of the diaphragm.   4. The speaker device according to claim 1, wherein the housing is formed with a drain hole. The speaker device according to claim 4, wherein the drain hole is formed continuously with the opening.

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