JP2736734B2 - Small vibration sensor for speaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small speaker / vibration sensor that detects vibration and generates an alarm sound and the like. A portable alarm that detects when a worker loses consciousness due to toxic gas, high temperature, etc. during work in a hazardous area such as fire fighting or emergency work, and generates an audible alarm. It has been known. There is also known an alarm device that detects vibration when glass is broken due to illegal intrusion or the like and generates an alarm. Such an alarm device includes a vibration sensor and a buzzer.

[0002]

2. Description of the Related Art As a conventional portable alarm, for example, a vibration sensor disclosed in Japanese Utility Model Laid-Open Publication No. 64-21772 is known. This vibration sensor is provided so that a metal ball can be moved between the diaphragm and the lid, a piezoelectric element is attached to the diaphragm, and the ball rolls on the diaphragm by external vibration, The vibration plate vibrates, the vibration is transmitted to the piezoelectric element, and a signal is generated from the piezoelectric element. That is, by detecting the output signal of the piezoelectric element, the presence or absence of external vibration can be detected. When an external vibration cannot be detected, that is, when the worker loses consciousness and falls down, the vibration cannot be detected. Therefore, the alarm device is driven to generate an alarm sound.

In a vibration sensor disclosed in Japanese Patent Application Laid-Open No. 53-54044, a ball is put inside a piezoelectric element, and the ball collides or rolls with the piezoelectric element by external vibration. Thus, a signal is generated from the piezoelectric element, and an external vibration is detected by detecting the signal. When this vibration sensor is applied to a portable alarm device, when an external vibration cannot be detected, the alarm device is driven to generate an alarm sound.

[0004]

A conventional vibration sensor generally uses a piezoelectric element, but is used only for detecting vibration. Therefore, a speaker or the like is provided to generate an alarm sound. That is, a vibration sensor and a speaker for generating an alarm sound and the like are separately provided. This made it difficult to reduce the size of the alarm. An object of the present invention is to reduce the size and cost by using a piezoelectric element as a vibration sensor and a speaker for generating an alarm sound or the like.

[0005]

Referring to FIG. 1, a small vibration sensor for a speaker according to the present invention has a piezoelectric element 1 having electrodes 1a and 1b on both surfaces, and a space in front of the piezoelectric element 1. A case 4 formed to support the piezoelectric element 1 by a support plate 2 and formed with a hole 3 for radiating a sound generated when a drive signal is applied to the piezoelectric element 1, And a rolling element 5 for generating a signal from the piezoelectric element 1 by colliding or rolling with the piezoelectric element 1 by the vibration of the piezoelectric element 1.

A detection circuit 6 for detecting a signal generated when the rolling element 5 collides or rolls with the piezoelectric element 1 due to external vibration, and a driving circuit 7 for applying a driving signal to the piezoelectric element 1 to generate a sound. And a switch circuit 8 for generating a sound by switching the piezoelectric element 1 from the detection circuit 6 to the drive circuit 7 in accordance with a detection signal for detecting the presence or absence of the external vibration by the detection circuit 6.

[0007]

When a vibration is applied from the outside, the rolling element 5 collides or rolls with the piezoelectric element 1, and a signal is generated from the piezoelectric element 1 in accordance with the collision or rolling. That is, vibration can be detected in the same manner as the conventional vibration sensor.
When a driving signal such as an alarm sound or various audio signals is applied to the piezoelectric element 1, a sound corresponding to the driving signal is generated from the piezoelectric element 1 and emitted from the hole 3 of the case 4. That is, it functions as a speaker.

When the piezoelectric element 1 and the detecting circuit 6 are switched and connected by the switch circuit 8 and it is determined that an abnormal state occurs when the vibration from the outside is stopped, the detecting circuit 6 detects the abnormal state from the piezoelectric element 1. When the signal is no longer applied, a detection signal is output, the piezoelectric element 1 and the drive circuit 7 are switched and connected by the switch circuit 8, the drive circuit 7 is activated, and the drive signal is applied to the piezoelectric element 1, and an alarm message or alarm is issued. Generate a sound.

[0009]

1A and 1B are explanatory views of a first embodiment of the present invention, wherein FIG. 1A is a top view, and FIG. 1B is a cross-sectional view, wherein 1 is a piezoelectric element, 1a and 1b are electrodes, and 2 is The supporting plate, 3 is a hole, 4 is a case, 5 is a rolling element, 6 is a detection circuit, 7 is a driving circuit, 8 is a switch circuit, 9 is an elastic adhesive, and 10 is a rolling element that surrounds the rolling element 5 so as to be able to roll. It is a moving case.

A piezoelectric element 1 having electrodes 1a and 1b on both surfaces
Is supported on the case 4 by the support plate 2. In this case, the tip of the support plate 2 is made thinner and mechanically and electrically fixed to the electrode 1a of the piezoelectric element 1 by soldering or the like, and an elastic adhesive 9 is provided at the fixed portion to reinforce. This elastic adhesive 9
For example, a silicone rubber-based adhesive can be used. With such a mounting structure of the piezoelectric element 1, vibration detection and sound generation by the piezoelectric element 1 can be facilitated. A rolling case 10 is provided on the front surface of the piezoelectric element 1 between the support plate 2 and the side wall of the case 4, and a rolling element 5 such as a sphere or a polyhedron is provided in the rolling case 10 so as to roll.

The switch circuit 8 can be constituted by a switching element such as a transistor.
The electrodes 1a and 1b of the piezoelectric element 1 are connected to the detection circuit 6 or the drive circuit 7 by switching. It is always switched and connected to the detection circuit 6,
The piezoelectric element 1 functions as a vibration sensor. Detection circuit 6
The drive circuit 7 is activated by the detection signal, and the drive circuit 7 is switched and connected to the electrodes 1a and 1b of the piezoelectric element 1, and the drive signal from the drive circuit 7 is applied to the piezoelectric element 1. 1 acts as a speaker. When a metal support plate 2 and a metal case 4 are used, the electrodes 1
Since a is connected to the support plate 2, the case 4 can be grounded and the electrode 1b can be insulated from the case 4 for wiring.

Further, a space surrounded by the support plate 2 and the case 4 is formed on the front surface of the piezoelectric element 1, and this space can be used as, for example, a resonance chamber. And the piezoelectric element 1
Is emitted from the hole 3 of the case 4 to the outside. In this case, the driving circuit 7 outputs, for example, a frequency of 1 to 2
When a drive signal with a voltage of about several tens of volts is output at kHz,
A warning sound of 1-2 kHz of about 100 phones is generated. In this case, if the drive signal is intermittent, the alarm sound is also intermittent. Although the rolling element 5 is also vibrated by the generation of the alarm sound, the sound caused by the alarm is at a level negligibly lower than the level of the alarm sound. The drive circuit 8 is provided with a sound reproducing function, a sound synthesizing function and the like, and by applying a sound signal to the piezoelectric element 1 as a drive signal, a message indicating danger or the like can be generated. Further, the detection circuit 6, the drive circuit 7, and the switch circuit 8 can be formed in a semiconductor integrated circuit and provided in the case 4. Thereby, the size can be reduced as a portable alarm device.

FIG. 2 is an explanatory diagram of a detection circuit, showing a main part when applied to a portable alarm, wherein 1 is a piezoelectric element, 7a
Is a drive circuit, 8a is a switch circuit, 11 is a signal output unit,
12 is a signal generation unit, 13 is a holding unit, 14 is a reset switch, R1 to R5 are resistors, C1 is a capacitor, Q1 and Q
2 is a transistor, CMP is a comparator, and V _CC is a power supply voltage.

The bias voltage is selected so that the transistor Q1 is turned on when a signal of a predetermined level or more is applied from the piezoelectric element 1, and when the transistor Q1 is turned on, the transistor Q2 is also turned on. Capacitor C
1 is charged via the resistor R5, and the charging time constant in this case is selected to be a relatively large value. The capacitor C1 is discharged when the transistor Q2 is turned on.
The comparator CMP, a reference voltage power supply voltage V _CC is formed by dividing by resistors R4, R1, R2, capacitor C
The terminal voltage of the capacitor C1 is compared with the terminal voltage of the capacitor C1. When the terminal voltage of the capacitor C1 becomes higher than the reference voltage, a detection signal is output and applied to the drive circuit 7a.

The drive circuit 7a has a configuration including a signal output section 11, a signal generation section 12, and a holding section 13. The signal generation section 12 is activated by a detection signal from a comparator CMP of the detection circuit. When the detection signal is held by the holding unit 13 and the switch circuit 8a is controlled, the piezoelectric element 1
From the detection circuit to the drive circuit 7a. An alarm signal or an alarm message is output from the activated signal generation unit 12 and is applied to the piezoelectric element 1 via the signal output unit 11. Thereby, the piezoelectric element 1 acts as a speaker and sends out an alarm sound or an alarm message. In this case, if the signal output unit 11 is configured to intermittently output an alarm signal at a predetermined cycle, the alarm sound from the piezoelectric element 1 is generated in an intermittent state. When the reset switch 14 is pressed, the holding unit 13 is reset, and the switch circuit 8a returns to the state shown in the figure.

As described above, in the portable alarm device, the rolling element 5 (see FIG. 1) applies vibration or impact to the piezoelectric element 1 until the worker carrying the alarm device loses consciousness and falls down. , A pulse signal is generated from the piezoelectric element 1. Therefore, the transistors Q1, Q
2 is turned on, and the capacitor C1 is intermittently discharged. Therefore, the terminal voltage of the capacitor C1 charged by the relatively long charging time constant does not exceed the reference voltage. That is, no alarm is issued.

However, when the worker loses consciousness and falls down,
The rolling element 5 is in a stationary state, and no pulse-like signal is generated from the piezoelectric element 1. Thereby, the transistor Q
1 and Q2 continue to be in the OFF state, and the capacitor C1 is not discharged. Therefore, the terminal voltage of the capacitor C1 rises. When the terminal voltage exceeds the reference voltage, a detection signal is applied from the comparator CMP to the drive circuit 7a. 8a is switched, a drive signal is applied, and an alarm sound is generated.

In FIG. 2, transistors Q1, Q2
And the circuit connection is changed so that the transistor C1 is always on, the transistors Q1 and Q2 are turned off by a pulse signal from the piezoelectric element 1, and the transistor C2 is always on, so that the capacitor C1 is turned on. When the charging is not performed, when the transistors Q1 and Q2 are turned off by a pulse signal from the piezoelectric element 1 due to external vibration, the terminal voltage of the capacitor C1 increases and exceeds the reference voltage. The detection signal is applied to the drive circuit 7a when the
In addition, the piezoelectric element 1 can generate an alarm sound. That is, it is possible to adopt a configuration in which an alarm sound is generated by vibration detection.

3A and 3B are explanatory views of a second embodiment of the present invention. FIG. 3A is a top view and FIG. 3B is a sectional view.
21B is a piezoelectric element, 21a, 21b, 21c and 21d are electrodes, 22 is a support plate, 23 is a hole, 24 is a case, 25 is a rolling element, and 30 is a rolling case. This embodiment is shown in FIG.
In this embodiment, piezoelectric elements 21A and 21B are provided on both sides. The illustration of the detection circuit, drive circuit, and switch circuit is omitted.

Since the rolling elements 25 can alternately apply a shock to the piezoelectric elements 21A and 21B on both sides by external vibrations, the vibration detection sensitivity can be increased. Further, the drive signal from the drive circuit is applied only to the piezoelectric element 21A, and the piezoelectric element 21A can be used as a vibration detection element that also functions as a speaker. Piezoelectric element 21 in that case
The alarm sound or the like generated by A is radiated to the outside through the hole 23 of the case 24. Further, the support plate 22 for supporting the piezoelectric element 21A on the case 24 can be reinforced by providing an elastic adhesive on a mounting portion as in the embodiment shown in FIG.

FIGS. 4A and 4B are explanatory views of a third embodiment of the present invention. FIG. 4A is a top view, FIG. 4B is a sectional view, 31 is a piezoelectric element, 32 is a support plate, 33 is a hole, 34 is a case, 35
A and 35B are rolling elements, and 40A and 40B are rolling cases. This embodiment is different from the embodiment shown in FIG. 1 in that two rolling cases 40A and 40B are provided, each of which has a rolling element 3A.
5A and 35B are provided so as to be able to roll, and it is also possible to provide a number of rolling cases and rolling elements. With such a configuration, the detection sensitivity of vibration can be increased. The operation as a speaker is the same as that of each of the above-described embodiments, and a small-size vibration sensor that also serves as a speaker can be configured. The detection circuit, the drive circuit, the switch circuit, and the like are not shown, and the structure for mounting the piezoelectric element 31 and the support plate 32 can adopt the structure shown in FIG.

FIGS. 5A and 5B are explanatory views of a fourth embodiment of the present invention. FIG. 5A is a top view, FIG. 5B is a sectional view, 41 is a piezoelectric element, 42 is a support plate, 43 is a hole, 44 is a case, 45
Is a rolling element. This embodiment shows a configuration in which the rolling elements 45 are arranged in the space between the support plate 42, the piezoelectric element 41, the side wall of the case 44, and the front plate, and corresponds to a case where the rolling range of the rolling elements 45 is widened. Since the rolling case can be omitted, there is an advantage that the size can be reduced. In addition, as in the above-described embodiments, it can function as a vibration sensor or as a speaker for generating an alarm sound. The detection circuit, the drive circuit, the switch circuit, and the like are not shown, and the structure for mounting the piezoelectric element 31 and the support plate 32 can adopt the structure shown in FIG.

FIGS. 6A and 6B are explanatory views of a fifth embodiment of the present invention. FIG. 6A is a top view, FIG. 6B is a sectional view, 51 is a piezoelectric element, 52 is a support plate, 53 is a hole, 54 is a case, 55
A, 55B, and 55C are rolling elements, and 56A and 56B are partition plates. This embodiment is different from the embodiment shown in FIG. 5 in that partition plates 56A and 56B are provided and rolling elements 55A, 55B and 5B are provided.
5C are arranged so as to be able to roll on the piezoelectric element 51, and the detection sensitivity is different between the case where the case 54 is held horizontally and the vibration is given and the case where the case 54 is held vertically and the vibration is given. Can be provided. In particular, there is a difference in the detection sensitivity depending on the position of the partition plates 56A and 56B when held vertically. In this embodiment as well, it can function as a vibration sensor and as a speaker for generating an alarm sound and the like as in the above-described embodiments.

FIGS. 7A and 7B are explanatory views of a sixth embodiment of the present invention. FIG. 7A is a top view, FIG. 7B is a sectional view, 61 is a piezoelectric element, 62 is a support plate, 63 is a hole, 64 is a case, 65
Is a rolling element, and 66 is a rolling case. In this embodiment, the peripheral portion of the piezoelectric element 61 is supported by a support plate 62, a rolling case 66 is provided at the center of the piezoelectric element 61, and a rolling element 65 is disposed inside the rolling case 66. Therefore, since the rolling element 65 rolls due to external vibration and a signal is generated from the piezoelectric element 61, it can function as a vibration sensor, and by applying a drive signal to the piezoelectric element 61, an alarm sound is generated. As a speaker.

FIGS. 8A and 8B are explanatory views of a seventh embodiment of the present invention. FIG. 8A is a top view, FIG. 8B is a sectional view, 71 is a piezoelectric element, 72 is a support plate, 73 is a hole, 74 is a case, 75
Is a rolling element, and 76 is a rolling case. This embodiment shows a case where the rolling case 76 of the embodiment shown in FIG. In this case, it is easy to widen the space formed on the front surface of the piezoelectric element 71, and the case 7
It is also possible to efficiently emit a warning sound or the like from the hole 73 of No. 4.

Also in the embodiment shown in FIGS. 1, 3, 4, 5, and 6, as in the embodiment shown in FIG. 8 with respect to the embodiment shown in FIG. A configuration in which rolling elements are arranged can be adopted. Although the piezoelectric element is shown as having a disk shape, it may be formed in a square shape or the like corresponding to the shape of the case. The position and configuration of the support plate for supporting the piezoelectric element in the case can be selected in consideration of the efficiency of vibration detection by the piezoelectric element and generation of sound such as an alarm sound. In addition, the hole for radiating alarm sounds etc. to the outside,
Although a single case is shown, a plurality of small holes can be used. When used outdoors, waterproof paper may be provided in the hole or the plurality of small holes to prevent raindrops from entering the piezoelectric element or the like. The case, the support plate, and the rolling elements can be made of metal or synthetic resin.

[0027]

As described above, according to the present invention, the piezoelectric element 1 having the electrodes 1a and 1b on both sides is supported by the support plate 2 in the case 4, and the rolling element 5 which rolls by external vibration is provided. Since the piezoelectric element 1 is disposed so that the piezoelectric element 1 is used for both vibration detection and sound generation such as an alarm sound, an economical configuration and downsizing can be achieved.
It can be applied to various alarms.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a detection circuit.

FIG. 3 is an explanatory diagram of a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a third embodiment of the present invention.

FIG. 5 is an explanatory diagram of a fourth embodiment of the present invention.

FIG. 6 is an explanatory diagram of a fifth embodiment of the present invention.

FIG. 7 is an explanatory diagram of a sixth embodiment of the present invention.

FIG. 8 is an explanatory diagram of a seventh embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 piezoelectric element 1a, 1b electrode 2 support plate 3 hole 4 case 5 rolling element 6 detection circuit 7 drive circuit 8 switch circuit 9 elastic adhesive

Claims (2)

(57) [Claims] 1. A piezoelectric element (1) having electrodes (1a, 1b) on both surfaces, and a space formed in front of the piezoelectric element (1) to support the piezoelectric element (1) by a support plate (2). And a case (4) having a hole (3) for emitting a sound generated when a drive signal is applied to the piezoelectric element (1), and a case (4) formed by external vibration in the case (4). The piezoelectric element (1) collides or rolls with the piezoelectric element (1)
And a rolling element (5) for generating a signal from the speaker. 2. A detection circuit (6) for detecting a signal generated when the rolling element (5) collides with or rolls on the piezoelectric element (1) due to external vibrations; A driving circuit (7) for generating a sound by adding a driving signal; and a detection signal indicating presence or absence of the external vibration by the detection circuit (6). 2. The small vibration sensor for speaker as claimed in claim 1, further comprising a switch circuit for generating a sound by switching to the drive circuit.