JPH07307992A - Speaker - Google Patents

Abstract

PURPOSE:To provide a speaker which can secure the larger voice output by attaching a diaphragm onto the inner circumferential surface of a casing only via the center part of the diaphragm. CONSTITUTION:A piezoelectric element 33 serving as a diaphragm is attached on the inner circumferential surface of a casing 31, that is, the element 33 is fastened and fixed to a projecting part 31a formed at the center part of the inner circumferential surface of the easing 1 by a screw 35. In other words, the element 33 is not fixed onto the inner circumferential surface of the casing 1 via an entire surface of the element like in a conventional case but fixed via only the center part of the element 33. Thus the part 31a functions as a transmitter part to transmit the vibrations of the element 33 to casing 1. In such a constitution, both diaphragm 33 and casing 31 can vibrate more easily so that the larger voice output is acquired. Furthermore it is not required to reduce the thickness of the casing 31 in order to increase the voice output. Thus it is possible to attain a satisfactory pressure-resistance structure by securing the necessary thickness for a speaker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker used in a communication device used underwater, for example, and in particular, a pressure resistant structure, a waterproof structure, a dustproof structure, and a large amplitude and a large volume can be obtained. Regarding things that have been devised so.

[0002]

2. Description of the Related Art A speaker in a conventional underwater communication device is constructed, for example, as shown in FIG. First,
There is a housing 101, and a piezoelectric element 103 as a vibration plate is attached to the inner peripheral surface of the housing 101 via the entire surface thereof. The piezoelectric element 103 is connected to a communication circuit (not shown) of a communication device via a signal cable 105. A right side opening of the casing 101 in the drawing is closed by a lid 107. Incidentally, reference numeral 109 in the figure denotes a seal ring. In the above configuration, the diaphragm 103 is vibrated by a signal received through the communication circuit, and the housing 101 is vibrated by this, whereby a desired sound is output.

Incidentally, as described above, the reason why the casing 101 is made to function as a speaker and the piezoelectric element 103 is used as a diaphragm is that it is not necessary to provide an opening in the speaker structure. This is because it is convenient for obtaining desired pressure resistance characteristics, waterproof characteristics, and dustproof characteristics.
Further, the piezoelectric element 103 has an advantage that it is thin and light, as compared with an ordinary speaker for acoustic use, and has characteristics that it has extremely high efficiency and low power consumption.

[0004]

The above-mentioned conventional structure has the following problems. First, there was a problem that the output was low and the sound was low. In order to solve this, for example, it is conceivable to reduce the thickness of the casing 101 to make it easier to vibrate. However, when the thickness of the casing 101 is decreased, the pressure resistance is reduced. Therefore, for example, when it is attempted to be used in water, there is a possibility that desired pressure resistance characteristics may be impaired. Further, when the wall thickness of the housing 101 is reduced, the pressure resistance characteristic is deteriorated as described above, whereby the housing is damaged (for example, cracked).
It is expected that things will be done. In that case, the waterproof structure and the dustproof structure of the speaker will be impaired. Further, it is expected that the diaphragm 103 may be damaged or deformed due to damage of the housing and deformation due to water pressure.

The present invention has been made on the basis of the above points, and an object of the present invention is to provide a speaker which can obtain a necessary pressure resistant structure, a waterproof structure, a dustproof structure, and a large amplitude and a large volume. To provide.

[0006]

In order to achieve the above object, a speaker according to the present invention comprises a housing and a diaphragm attached to an inner peripheral surface of the housing and connected to the housing only through a central portion thereof. And is provided. At that time, it is conceivable to project a convex portion on the inner peripheral surface of the housing and attach the diaphragm to the convex portion. In addition, it is considered that a plurality of diaphragms are provided, the first one is attached to the convex portion, and thereafter, the diaphragms are sequentially attached in a state of being laminated via a spacer. Further, as a method of attaching the diaphragm, it is conceivable to use a screw or an adhesive.

[0007]

That is, the speaker according to the present invention has a structure in which the diaphragm is attached to the inner peripheral surface of the housing.
The diaphragm is connected to the inner peripheral surface of the housing only through the central portion thereof. That is, the diaphragm is in a state of being separated from the inner peripheral surface of the housing except the central portion thereof. With this configuration, both the diaphragm and the housing are more likely to vibrate, and as a result, a larger audio output can be obtained. At that time, it is conceivable that a convex portion is provided on the inner peripheral surface of the housing so that the diaphragm is attached to the convex portion. It should be noted that not only the convex portion is projected, but, for example,
It is also conceivable to attach via a spacer.
In addition, it is possible to stack and arrange multiple diaphragms with a space and attach them to the housing side in that state. In that case, the number of diaphragms increased The force is increased, which allows a greater increase in audio output. Further, as a method of attaching the diaphragm, fixing with screws, adhesive fixing, or the like can be considered.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 to 4 and 8. This embodiment is a diagram showing an example in which the present invention is applied to an underwater communication device. First, there is a communication circuit 1, and a microphone 3, a speaker 5, and a transmission / reception sensor 7 are connected to the communication circuit 1, respectively. First, the signal from the microphone 3 passes through the filter 9 and is input to the audio signal amplifier 11 where it is amplified.
Then, it is input to the modulator 13 and modulated, and the filter 1
It is input to the output amplifier 17 through 5. It is amplified in this output amplifier 17 and input to the transmission / reception switch 19, and from there, it is transmitted to the ship or the like via the transmission / reception sensor 7 already described. In addition, the transmission / reception switch 1
A transmission / reception changeover switch 21 is connected to the switch 9, and the user switches the transmission / reception by appropriately installing the transmission / reception changeover switch 21.

On the other hand, the signal from the ship or the like input via the transmission / reception sensor 7 is input to the preamplifier 23 via the transmission / reception switcher 19. It is amplified in the preamplifier 23 and input to the demodulator 25. The signal demodulated by the demodulator 25 passes through the filter 27 and the audio output amplifier 2
9 is input. The signal amplified by the audio output amplifier 29 is input to the speaker 5 already described, and is output as an audio signal there.

Next, the structure of the speaker 5 will be described. FIG. 2 is a cross-sectional view showing the main part of the speaker 5. First, there is a casing 31 made of polycarbonate. The case 3
In this embodiment, No. 1 has an outer diameter of 95 mm and a wall thickness of 5 mm. A piezoelectric element 33 as a vibrating plate is attached to the inner peripheral side of the housing 31. In the mounting structure of the piezoelectric element 33, a convex portion 31a is provided at the center of the inner peripheral surface of the housing 31 so as to project. The piezoelectric element 33 is fastened and fixed to the convex portion 31a with a screw 35. In this embodiment, the convex portion 31a has an outer diameter of 5 mm and a height of 1 mm. That is, unlike the conventional case, the piezoelectric element is not bonded and fixed to the inner peripheral surface of the housing through the entire surface thereof, but is connected only through the central portion thereof. That is, the convex portion 31 a functions as a transmission portion that transmits the vibration of the piezoelectric element 33 to the housing 31. The opening on the right side of the housing 31 in the figure is closed by a lid 37 via a seal ring 39.

The piezoelectric element 33 is constructed as shown in FIGS. 3 and 4. First, there is a metal plate 41, and a piezoelectric ceramic 43 is attached to the central portion of the metal plate 41. In addition, in FIG. 2, one signal line is connected to the piezoelectric element 33, but in reality, as shown in FIGS. 3 and 4, the metal plate 41 and the piezoelectric ceramic 43 are shown. The signal lines 45 and 47 are connected to each of the above. The piezoelectric element 33 having such a configuration has a characteristic that it expands when an anode (+) is applied and contracts when a cathode (−) is applied. Therefore, it has a characteristic that an audible sound is generated by the distortion motion of the metal plate 41 when an AC signal is applied within the audible frequency range.
Further, regarding the dimensions of each part in this embodiment, the metal plate 4
The outer diameter of 1 is 24.7 mm, and the thickness of the piezoelectric ceramic 43 is 0.28
mm, and the thickness of the metal plate 41 is 0.25 mm.

The operation will be described based on the above configuration. The operation of the communication device as a whole is as described above, and the operation of the speaker 5 will be described here. A signal from the ship or the like input through the transmission / reception sensor 7 is used as a transmission / reception switch 19, a preamplifier 23, a demodulator 25, a filter
7. It is input to the speaker 5 via the audio output amplifier 29. Thereby, first, the piezoelectric element 33 vibrates. The vibration of the piezoelectric element 33 is generated by the protrusion 3 of the housing 31.
It is transmitted to the housing 31 via 1a, which causes the housing 31 to vibrate. By vibrating the housing 31, a desired audio output can be obtained. When this is seen from the experimental result, it becomes as shown in FIG. In FIG. 8, the horizontal axis represents frequency and the vertical axis represents sound pressure level. The characteristics of the conventional example shown in FIG. 9 (indicated by a broken line in the figure) and the characteristics of this example (in the figure) FIG. 6 is a characteristic diagram showing a comparison of (shown by a solid line). As is clear from FIG. 8, the sound pressure level is significantly increased.

The characteristic diagram shown in FIG. 8 will be described in detail. First, in the experiment, white noise was used as a sound source, the same input voltage was applied, and the dynamic microphones were separated by 5 cm in the air. As a result, as shown in FIG. 8, an average sound pressure increase of 15.4 dB could be obtained within the range of 500 Hz to 4 KHz. In particular, a remarkable improvement was observed in the range of 1 KHz to 3 KHz, which is the range of use.

According to this embodiment, the following effects can be obtained. First of all, it became possible to obtain a large voice output. This is because the piezoelectric element 33 is configured to be connected to the inner peripheral surface of the housing 31 only through the center of the piezoelectric element 33, rather than being bonded to the inner peripheral surface of the housing 31 through the entire surface thereof. Is. That is, the piezoelectric element 33
This is because the piezoelectric element 33 and the housing 31 are more likely to vibrate by being configured to be connected only via the center of the.

Further, since it is not necessary to reduce the wall thickness of the casing 31 in order to increase the sound output, it is possible to secure a necessary thickness and obtain a sufficient pressure resistant structure. Further, when the wall thickness of the housing 31 is reduced in order to increase the sound output, there is a concern that the pressure resistance may be deteriorated and the damage (for example, cracks) may be caused, thereby damaging the waterproof structure and the dustproof structure. However, in the case of this embodiment, such a situation does not occur because the necessary thickness can be secured and a sufficient pressure resistant structure can be obtained as described above. In the first embodiment, the convex portion 3 is provided on the side of the housing 31.
Instead of projecting 1a, a washer as a spacer may be inserted there.

Next, a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, the piezoelectric element 33 is fastened and fixed to the convex portion 31a of the housing 31 by using the screw 35, but in the case of this embodiment, the piezoelectric element 33 is fixed to the convex portion 31a.
It is adapted to be bonded and fixed to a by an adhesive. In the figure, the adhesive portion is shown by reference numeral 37. Even with this structure, the same effect as that of the first embodiment can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIG. In the case of the first and second embodiments, one piezoelectric element 33 is used, whereas in the case of the third embodiment, a plurality of piezoelectric elements 33 (5 in this embodiment) are used.
The number of piezoelectric elements 33 is arranged in series to increase the output. Although its mounting structure,
Four washers 39 are inserted between five piezoelectric elements 33, which are fastened and fixed to the convex portions 31a by screws 35. In this case, all of the five piezoelectric elements 33 vibrate, and these are added to form the convex portion 31.
It is transmitted to the housing 31 via a. Therefore, the piezoelectric element 3
Larger vibration energy is transmitted to the housing 31 as compared with the case where the number of the housings 3 is one, and the vibration of the housing 31 is correspondingly large. Therefore, a larger audio output can be obtained.

Incidentally, in the case of the conventional speaker configuration, if the sound output is to be increased, the only method is to increase the number of speakers themselves. For example, it is conceivable to increase the voltage applied to the piezoelectric element 33 (the piezoelectric element 33 is structurally driven by a voltage, the current flowing at that time is about several mA, and the power consumption is extremely small). However, there is a limit to the voltage that can be applied to the piezoelectric element 33 (usually used at about 30 V), and if a high voltage higher than the allowable maximum voltage is applied, the piezoelectric element 33 will be damaged. On the other hand, in the case of the present embodiment, the driving force for driving the transmission portion is increased simply by appropriately increasing the number of piezoelectric elements 33 and arranging them in series (electrically parallel driving). Therefore, a desired sound output increasing effect can be obtained without increasing the applied voltage.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In the case of the third embodiment, the five piezoelectric elements 33 are fastened and fixed to the convex portion 31a by the screws 35 via the four washers 39, but in the case of this embodiment, Is five piezoelectric elements 33 and four washers 3
It is adapted to be adhered and fixed to the convex portion 31a via 9. Even with this structure, the same effect as in the case of the third embodiment can be obtained.

The present invention is not limited to the first to fourth embodiments. First, as the mounting structure of the piezoelectric element 33, various structures other than fixing by screws and adhesive fixing can be considered. Just do it. or,
At this time, the distance between the piezoelectric element 33 and the housing 31 is not particularly limited. Also, a plurality of piezoelectric elements 3
When 3s are arranged and attached in series, the number of them may be arbitrarily determined. Also on the housing 31 side, it is not always necessary to project the convex portion 31a, and for example, a gap may be provided by means such as inserting a washer. Further, in each of the above-described embodiments, the piezoelectric element 33 is attached to the center position of the inner peripheral surface of the housing 31, but the position is not necessarily limited to the center position.

[0021]

As described in detail above, according to the speaker of the present invention, the diaphragm is attached to the inner peripheral surface of the housing,
Since the diaphragm is configured to be connected to the inner peripheral surface of the housing only through its center, both the diaphragm and the housing are more likely to vibrate, and as a result, a larger audio output can be obtained. Will be able to. In addition, when a plurality of diaphragms are stacked and arranged at intervals and attached to the housing side in that state, the driving force for driving the transmission part increases due to the increase in the number of diaphragms. Therefore, the voice output can be further increased.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an underwater communication device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a main part of a speaker, which is a diagram showing a first embodiment of the present invention.

FIG. 3 is a plan view of the piezoelectric element according to the first embodiment of the present invention.

FIG. 4 is a side view of the piezoelectric element according to the first embodiment of the present invention.

FIG. 5 is a sectional view showing a configuration of a main part of a speaker in a diagram showing a second embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a configuration of a main part of a speaker in a view showing a third embodiment of the present invention.

FIG. 7 is a sectional view showing a configuration of a main part of a speaker, which is a view showing a fourth embodiment of the present invention.

FIG. 8 is a characteristic diagram for explaining an effect in the case of the first embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a configuration of a main part of a speaker, showing a conventional configuration.

[Explanation of symbols]

 5 Speaker 31 Housing 31a Convex part 33 Piezoelectric element (vibration plate) 35 Screw 37 Adhesive part 39 Washer (spacer)

Claims (5)

[Claims] 1. A speaker comprising: a casing; and a diaphragm attached to an inner peripheral surface of the casing and connected to the casing only through a central portion thereof. 2. The speaker according to claim 1, wherein a convex portion is provided on the inner peripheral surface of the housing so that the diaphragm is attached to the convex portion. 3. The speaker according to claim 2, wherein a plurality of diaphragms are provided, and the first one is attached to the convex portion, and subsequently attached in a state of being sequentially laminated via the spacer. . 4. The speaker according to claim 1, 2, or 3, wherein the diaphragm is fastened and fixed with a screw. 5. The speaker according to claim 1, 2, or 3, wherein the diaphragm is adhesively fixed.