JP3026220B2 - Ultrasonic open / close detection method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic open / close detection method and apparatus for detecting the open / close state of an open / close device such as a door using an ultrasonic wave. The present invention relates to an ultrasonic open / close detection method and apparatus for detecting and detecting an open / close state of an open / close device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, an interlocking switch SWn for switching an AC power supply AC capable of variably operating a frequency f through a detection resistor R in accordance with the opening / closing operation of each switchgear as shown in FIG. And this interlocking switch SW
n reactance Ln and capacitor Cn
Each of the resonance circuits LC is connected in parallel. Each of the resonance circuits LC is set in advance so as to resonate at a different resonance frequency corresponding to each switching device, and which interlocking switch SWn performs the switching operation,
The change characteristic of the output voltage V may be previously detected in each resonance state of each resonance circuit LC so that the change can be detected by detecting the change in the output voltage V of the detection resistor R. That is, the interlock switch SW ₂ is turned on in FIG.
In the state, when the frequency f of the AC power supply AC is continuously varied, the resonance frequency f ₂ of the resonance circuit LC ₂ is changed.
In resonates the resonant circuit circuit LC _2, this time, flows in large current resonance circuit LC _2, the voltage across the resultant detection resistor R is rapidly changed. Detecting the alternating current power source AC frequency f at this time, that the interlock switch SW ₂ of the resonant circuit LC ₂ catches that in the ON state, were made to open and close the corresponding switchgear to interlock switch SW ₂ Can be detected.

[0003]

However, according to this detection method, a large space is required for the reactance Ln of the resonance circuit LC and the capacitor Cn, and the device itself is inevitably increased in size. The power consumption by the resonance circuit LC is so large that many detections cannot be performed by one device. And so on.

The present invention has been made in view of the above circumstances, and does not use a resonance circuit LC which causes an increase in the size of a device, and has a compact ultra-high-impedance configuration in which a large number of detection units can be installed due to high impedance. It is an object of the present invention to provide a method and apparatus for detecting sound wave opening and closing.

[0005]

In order to solve the above-mentioned problems, the present invention provides a method of simultaneously generating longitudinal vibration in a vibration mode Lm (m is an arbitrary integer) and bending vibration in a vibration mode Bn (n is an arbitrary integer). At least one pair of piezoelectric bodies is provided on the front and back of a plate-like elastic body formed to have a dimensional shape to occur,
A high-frequency power source is connected to one of the pair of piezoelectric bodies to excite it, and the other piezoelectric body is connected to a charge changing means for changing the charge of the piezoelectric body in accordance with opening and closing of a switching device, and the electric charge of the piezoelectric body is changed. It is characterized in that it changes according to the opening and closing of the switching device, and detects the open / closed state of the switching device by capturing a change in the resonance frequency of the one piezoelectric body caused by the change in the electric charge.

Further, according to the present invention, there is provided a plate-shaped member formed so as to have a dimensional shape in which a longitudinal vibration in a vibration mode Lm (m is an arbitrary integer) and a bending vibration in a vibration mode Bn (n is an arbitrary integer) occur simultaneously. At least one pair of piezoelectric members on the front and back of the elastic member, a high-frequency power supply connected to one of the pair of piezoelectric members for ultrasonically exciting the piezoelectric member, and changing the electric charge of the other piezoelectric member according to the opening and closing of the switching device And a detecting means for capturing a change in the resonance frequency of one of the piezoelectric bodies caused by the charge varying means.

[0007]

By using the high-impedance ultrasonic vibrating section having the above configuration, a plurality of ultrasonic vibrating sections can be provided in parallel with the switching device as required.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing a configuration of the ultrasonic opening / closing detection device of the present invention, and FIG. 3 is a characteristic diagram showing a change in a resonance frequency of a detection unit of the ultrasonic opening / closing detection device. The application is
As shown in FIGS. 2 and 3, an interlocking switch SWn is provided to an AC power supply AC capable of variably operating the frequency f via a detection resistor R to follow and switch the opening and closing operation of each switchgear. The resonance frequencies that change in the ON-OFF state are all different, and each of the ultrasonic vibrating parts MSn whose resonance frequencies are set in advance so that it is possible to detect which interlocking switch SWn has been switched from each resonance frequency is opened and closed by the switching device. A plurality are connected in parallel depending on the section.

First, the ultrasonic vibration section MSn will be described. In the figure, reference numeral 10 denotes an elastic vibrator, and reference numerals 12a and 12b denote piezoelectric elements. Based on a known design technique, the elastic vibrating body 10 has a length and a thickness such that the longitudinal vibration and the bending vibration generated when the piezoelectric elements 12a and 12b are excited substantially coincide with each other. Is formed. Each of the piezoelectric elements 12a and 12b has an elastic vibration member 10 such that a node of the longitudinal vibration generated at the middle point in the longitudinal direction of the elastic vibration member 10 is located substantially at the center of each of the piezoelectric elements 12a and 12b in the longitudinal direction. It is arranged above. The line 13 is connected to the piezoelectric elements 12a and 12b.
a and 13b are connected to each other. The line 13a is connected to one end of an AC power supply AC via a detection resistor R, and one of the lines 14a and 14b connected to both ends of the elastic vibrator 10 is connected to the AC power supply AC. Connected to the other end.

An interlocking switch SWn is provided between the lines 13b and 14b, which are not shown, to follow the opening / closing means of each switching device and to perform switching operation. I have.

In general, an AC power supply AC applies an alternating voltage of a specific frequency to the piezoelectric element 12a to generate a predetermined mode of longitudinal vibration and bending vibration in the elastic vibrator 10, and a frequency variable circuit (not shown). Conversion circuit for converting a voltage value input from the FB into a specific frequency, a waveform shaping circuit for setting the output from the VF conversion circuit to a duty of 50%, and a drive circuit for driving the piezoelectric element 12a It is composed of

The frequency variable circuit includes an initial voltage setting circuit, an integrating circuit, and a voltage adding circuit, and fluctuates a voltage value input to the VF conversion circuit, and is applied to the piezoelectric element 12a. This is for changing the frequency of the alternating voltage. The initial voltage setting circuit previously holds the initial value of the voltage applied to the VF conversion circuit by the voltage adding circuit, and the resonance frequency at which the elastic vibration body 10 excites the longitudinal vibration and the bending vibration or the vicinity thereof. The voltage value corresponding to the nearby frequency is held and sent to the voltage adding circuit. The integration circuit generates a voltage value that continuously changes in a rising direction or a falling direction and sends the voltage value to a voltage addition circuit. The integration circuit calculates a voltage value supplied from the voltage addition circuit to the VF conversion circuit. The piezoelectric element 1
The frequency of the alternating voltage applied to 2a is changed.

Next, the ultrasonic vibrating section MS having the above configuration
The function of n will be described. First, as shown in FIG. 4, as the elastic vibrator 10, a dimension and a shape in which a longitudinal vibration in a vibration mode L ₁₀ (one node) and a bending vibration in a vibration mode B ₂₀ (two nodes) occur simultaneously by resonance. The case of using the one formed so as to have the following will be described. For example, when exciting the piezoelectric element 12a (at a predetermined longitudinal vibration resonance frequency of the elastic vibration member 10) selectively, with the vibration mode L ₁₀ of the longitudinal vibration is generated in the length direction of the elastic vibration member 10, the longitudinal vibration sympathetic vibration mode B ₂₀ of the bending vibration is induced in the.
These two vibrations are combined, and thus an elliptical vibration is generated on the surface of the elastic vibration body 10.

Next, the opening / closing detection operation will be described. First is interlock switch SW ₂ as shown in Figure 2 will be described for the case where a follow-up to the ON state to the opening and closing operation of the unshown opening and closing device. When the frequency of the AC voltage AC as described above go continuously varies, because the interlock switch SW ₂ as shown in Figure 3 is in the ON state, the ultrasonic vibration unit MS ₂ is resonant at a frequency f _2a where should the resonant frequency of the ultrasonic vibration unit MS ₂ by close mutual agreement to the charge amount is zero or zero of the piezoelectric element 12b is changed and f _2b, the frequency f of the AC voltage AC resonates f _2b, the At this time, the voltage across the detection resistor R changes abruptly. At this time, the frequency f = f _2b of the AC power supply AC is detected, and it is detected that the interlocking switch SW ₂ of the ultrasonic vibrating unit MS ₂ has been turned on, and the opening and closing of the switching device corresponding to the interlocking switch SW ₂ is performed. What has been done can be detected. Hereinafter, the same may be detected for another switching device.

As described above, the ultrasonic open / close detection method and apparatus according to the present invention captures a change in the resonance frequency of an elastic vibrator vibrated by an ultrasonic wave due to the open / close state of the open / close device, and detects the open / close state of the open / close device. , A compact ultrasonic open / close detection method and apparatus that does not use the resonance circuit LC that causes an increase in the size of the apparatus and that can install many detection units due to high impedance. It is intended to provide.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a conventional open / close detection device.

FIG. 2 is a diagram showing a configuration of an ultrasonic open / close detection device of the present application.

FIG. 3 is a diagram for explaining a change in a resonance frequency of an ultrasonic open / close detection unit in the ultrasonic open / close detection device of the present application.

FIG. 4 is a diagram for explaining a vibration state of an ultrasonic open / close detection unit in the ultrasonic open / close detection device of the present application.

[Explanation of symbols]

 Reference Signs List 10 elastic vibration body 12a piezoelectric element (piezoelectric body) 12b piezoelectric element (piezoelectric body) SWn interlocking switch AC AC power supply (high-frequency power supply)

Claims (2)

(57) [Claims] 1. An apparatus for detecting the open / closed state of a switchgear, wherein a longitudinal shape of a vibration mode Lm (m is an arbitrary integer) and a bending vibration of a vibration mode Bn (n is an arbitrary integer) are simultaneously generated. At least one pair of piezoelectric members is provided on the front and back of a plate-like elastic member formed so as to have a high-frequency power source connected to one of the pair of piezoelectric members, and the other piezoelectric member is opened and closed by a switching device. Is connected to a charge varying means for varying the charge of the piezoelectric body in response to the change of the resonance frequency of the one piezoelectric body caused by the variation of the charge. An ultrasonic open / close detecting method for detecting the open / close state of the open / close device by capturing the open / close state. 2. A device for detecting an open / close state of a switchgear, wherein a dimension and a shape in which a longitudinal vibration in a vibration mode Lm (m is an arbitrary integer) and a bending vibration in a vibration mode Bn (n is an arbitrary integer) occur simultaneously. At least one pair of piezoelectric members on the front and back of a plate-like elastic member formed so as to have a high-frequency power source connected to one of the pair of piezoelectric members and ultrasonically exciting the piezoelectric member; An ultrasonic open / close detecting apparatus comprising: a charge varying means for varying the charge of the other piezoelectric body; and a detecting means for detecting a change in the resonance frequency of the one piezoelectric body caused by the charge varying means.