JPS5920091B2 - Abnormal pressure detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an abnormal pressure detection device, and in particular to an abnormal pressure detection device, in which energy emitted from a transmitting device is temporarily stored in a crystal oscillator, and based on the stored energy, energy emitted from the crystal oscillator is released. The present invention relates to an abnormal pressure detection device that monitors the pressure in a closed space by receiving released energy, and issues, for example, an alarm when the pressure reaches a dangerous level.

Various devices and equipment that have a closed space are monitored for a drop in the pressure in the closed space (.), and an alarm is often issued when the pressure drops abnormally (.). It becomes necessary.

For example, in the case of a car, it is important to detect an abnormal drop in tire pressure and issue a warning in order to prevent accidents.

An object of the present invention is to provide a novel abnormal pressure detection device that detects abnormal pressure in a closed space and generates an alarm, for example. Therefore, it is difficult to supply power to the abnormal pressure detection means installed in the tire (for example, even if power is supplied by a battery or the like, it is difficult to replace it.

), and taking into account that it is difficult to obtain information from the abnormal pressure means through wired connection, at least the above abnormal pressure detection means operates without power supply, and the abnormal pressure detection means does not detect any abnormality from the abnormal pressure detection means. An object of the present invention is to provide an abnormal pressure detection device that can receive pressure detection information without or without wired connection.

There is a method that has been proposed in the past for the same purpose as the present invention, in which the response of the pressure response means is detected by an LC resonant circuit.

The LC resonant circuit consisting of this coil and capacitor generally has a Q
Because the temperature is low and the amount of energy stored there is small (・), the duration of vibration after excitation stops is extremely short, making it extremely difficult to detect it.

Therefore, in an abnormal pressure detection device using the LC circuit, for example, Japanese Patent Application No. 50-116915 (Japanese Unexamined Patent Publication No. 52-4
No. 0183), an LC circuit is constantly excited from an energy transmitting/receiving means, and the signal emitted from the LC circuit in response to the response of the pressure responsive means is combined with the signal for the above excitation. The configuration is such that the response state of the pressure response means is detected based on the phase after the synthesis, but according to this conventional method, the phase processing circuit for performing phase synthesis and phase detection is configured to perform phase synthesis between Furthermore, due to the low Q of the LC resonant circuit, a steep resonance characteristic cannot be obtained.Therefore, there is a difficulty in the frequency selectivity of the detection signal, and in order to overcome this, the phase processing circuit means described above is required. The configuration becomes complicated, and its adjustment becomes extremely difficult.

In view of the above conventional problems, another object of the present invention is to provide an abnormal pressure detection device that does not require complicated phase detection and can monitor pressure abnormalities by simply determining the presence or absence of a signal from a pressure detector. The aim is to realize this.

In order to achieve the above object, the present invention comprises an abnormal pressure detector comprising a pressure responsive switch, a crystal oscillator, and an energy transmitting/receiving coil, and when the crystal oscillator is excited, the Q of the crystal oscillator is high. Even if the excitation energy is cut off, the crystal oscillator will continue to vibrate for a relatively long period of time due to the energy stored in it.Using this fact, the pressure-responsive switch can be operated without power supply and with a wired connection. It is now possible to transmit the signal to the outside of a closed space at °C without physical coupling.

That is, when a coil serving as a means for transmitting and receiving energy is connected to the terminals of a crystal oscillator, and a transmitter sends out a radio signal with a frequency that matches the natural vibration frequency of the crystal oscillator as excitation energy, the crystal oscillator is transmitted through the coil. The radio wave signal is applied to the crystal resonator, and the crystal resonator resonates.

The resonance phenomenon of the crystal resonator is thus induced by the radio wave signal from the transmitter, but even if the transmission of the radio wave signal from the transmitter is stopped, the excited crystal resonator immediately stops the resonance phenomenon. Instead, it continues to vibrate while being damped by the energy stored in the crystal oscillator, and the Q of the crystal oscillator is high (because of this, this damped oscillation continues for a relatively long time).

Therefore, even after the transmitter stops transmitting radio signals, a resonance signal due to the energy released from the crystal oscillator is emitted through the coil for a certain period of time, and by receiving it, the pressure in the closed space can be monitored. is possible.

Hereinafter, the present invention will be explained in detail with reference to FIG.

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, in which 1 is a crystal oscillator, 2 is a pressure-responsive switch that acts as a pressure-responsive means, 3 is a coil that acts as an energy transmitting/receiving means, 4 is a transmitter/receiver, 5 is an antenna, and 6 is a closed space.

In the sealed space 6, an abnormal pressure detector is installed, which includes a crystal oscillator 1, a coil 3, and a pressure responsive switch 2 connected in parallel.

The pressure responsive switch 2 is a switch that closes when the pressure drops below a set value.

When the pressure in the sealed space 6 is higher than the response setting value of the pressure response switch 2 (at normal pressure), the pressure response switch 2 opens as shown in Fig. .

In this state, when the transceiver 4 is operated as a transmitter (transmission mode) and a radio wave signal equal to the natural vibration frequency of the crystal resonator 1 is transmitted from the transceiver 4 via the antenna 5, the radio signal is transmitted to the coil. 3 is received by the abnormal pressure detector, and the crystal oscillator 1 of the abnormal pressure detector resonates due to the energy.

Even after the transmitter/receiver 4 stops transmitting the radio signal, the crystal oscillator 1 continues to vibrate for a while while attenuating as described above, so the transmitter/receiver 4 stops transmitting the radio signal. If the transmitter/receiver 4 is immediately switched to function as a receiver (receiving mode), it is possible to receive the damped vibration wave of the crystal resonator 1 via the antenna 5. It is possible to detect that the pressure is normal.

If the pressure in the sealed space 6 falls below the response setting value of the pressure response switch 2 (when the pressure becomes abnormal), the pressure response switch 2 closes and shorts the terminals of the crystal oscillator 1, so that transmission and reception are possible. Even if a radio wave signal is transmitted from the transmitter 4, the crystal oscillator 1 does not resonate and no energy is stored. No damped oscillation waves are sent out, and no signal is received by the transceiver 4.

As a result, it is detected that the pressure within the closed space 6 has decreased abnormally, and an appropriate alarm is issued based on this.

In addition, a plurality of abnormal pressure detectors whose crystal oscillators 1 have different natural oscillation frequencies are installed in a plurality of closed spaces 6, and the transmitter/receiver 4 has a transmission/reception frequency that matches the natural oscillation frequency of each crystal oscillator 1. If you send and receive the following sequentially,
It is possible to identify and detect the presence or absence of an abnormal change in pressure in a plurality of sealed spaces 6.

As described above, in the present invention, an extremely high-Q crystal oscillator is used as a means for detecting the response state of the pressure response means, the crystal oscillator is excited, and the excitation is stopped. After the above-mentioned crystal resonator detects the damped oscillation that persists at °C based on the energy stored in it, the configuration of the transceiver is such that after sending out the radio signal (excitation energy) in the transmission mode, The device configuration is extremely simple (same frequency signal transmission/reception function), as long as it can detect whether there is a reply (reception of damped oscillation waves) from the abnormal pressure detector by switching to reception mode for several meters of 5ec. It would be good if it had a function to switch between transmission and reception.

), and since the frequency of the damped oscillation wave sent out from the abnormal pressure detector is determined by the natural oscillation frequency of the crystal oscillator, the transmitted and received signals have steep frequency selectivity. There are very few false positives.

Also, the crystal oscillator of the abnormal pressure detector is external (transmitter/receiver).
Since the abnormal pressure detector can be configured without a power source because it is excited by the First, since the shape of the coil serving as the energy transmitting/receiving means can be freely set, the mounting position of the abnormal pressure detector can be freely set.

As described above, the present invention has various advantages, and the effects are extremely significant.

In addition, in the embodiment shown in Fig. 1, a case was described in which the case where the pressure in the closed space was detected to be abnormally low was described, but if the pressure responsive switch is set to a switch that operates when the pressure becomes abnormally high, An abnormal increase in pressure within a closed space can be detected, and such cases are also included in the gist of the present invention.

In addition, in the example, the crystal resonator, the coil, and the pressure-responsive switch were connected in parallel, and the terminals of the crystal resonator were short-circuited by the action of the pressure-responsive switch. The present invention can also be practiced by connecting a pressure-responsive switch in series and opening the closed loop between the crystal resonator and the coil by actuation of the pressure-responsive switch.

Furthermore, in the example, when the pressure is normal, the crystal oscillator vibrates,
The structure was configured so that the crystal oscillator stops vibrating when there is abnormal pressure, but by making some changes, this relationship can be reversed, that is, when the pressure is normal, the crystal oscillator stops vibrating. Alternatively, the crystal oscillator may be configured to vibrate when abnormal pressure occurs.

In addition, in the example, the entire abnormal pressure detector was installed in a closed space, but among the parts constituting the abnormal pressure detector,
The present invention can be implemented by installing at least a pressure-responsive switch in a closed space.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram illustrating the present invention in detail. Explanation of symbols, 1...Crystal oscillator, 2...Pressure responsive switch, 3...Coil, 4...Transmitter/receiver, 5...
Antenna, 6...closed space.

Claims (1)

[Claims] 1. An abnormal pressure detection device that detects that the pressure in a closed space has changed outside of a set value range, which includes a pressure response means that responds when the set pressure is reached, and a quartz crystal. a vibrator, which receives excitation energy, supplies the excitation energy to the crystal resonator according to the response state of the pressure response means, and releases energy emitted by the crystal resonator when the supply of the excitation energy is cut off; An abnormal pressure detector consisting of a radiating energy transmitting/receiving means, which emits excitation energy of the crystal oscillator in a transmission mode, then stops the emission of the excitation energy and switches to a reception mode, and emits the excitation energy of the crystal oscillator. An abnormal pressure detection device consisting of a transmitter/receiver that receives energy. 2. The abnormal pressure detection device according to claim 1, wherein at least the pressure responsive means is installed in a closed space. 3. The abnormal pressure detection device according to claim 1, wherein the energy transmitting/receiving means is a coil. 4. The abnormal pressure detection device according to claim 1 or 2, wherein the pressure response means is a switch that turns on or off after a set pressure is reached.