JPH04519Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a relay using electrostrictive effect.

In recent years, piezoelectric ceramics mainly made of zircon and lead titanate, which have large piezoelectric constants, have been developed. Therefore, the operation of bimorph elements using this is often applied to relays. In this case, unlike the conventional electromagnetic type, the driving force source is a voltage, and the advantage is that energy loss is extremely small compared to the electromagnetic type, which generates a magnetic field by current and uses magnetic force.

However, piezoelectric bimorphs have a problem with operational reliability because they have a large strain hysteresis that cannot be ignored. Furthermore, in order to create sufficient electrical contact, a high voltage must be applied as an input, and strength such as withstand voltage is required.

On the other hand, in the case of electromagnetic type relays, not only DC but also AC type operating power sources have been developed and used, but in the case of piezoelectric type bimorphs, when AC voltage is applied, the bimorph vibrates and the relay It impairs the function of the product and cannot be used as is. For example, a piezoelectric relay is known that utilizes the piezoelectric effect to conduct and disconnect depending on the upper and lower positions of the mercury liquid level (Japanese Patent Publication No. 49-33498).
However, since this configuration assumes DC drive, if an AC voltage is directly applied, the mercury liquid level position will oscillate up and down depending on the frequency, making it impossible to achieve the function of the relay.

In view of these points, the present invention is an electrostrictive relay that has an electrostrictive bimorph structure that uses voltage as a driving source, resulting in extremely low energy loss compared to electromagnetic relays, and that can apply direct current and alternating current voltage. The main purpose is to propose.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an example of an electrode portion constituting an electrostrictive bimorph element. Reference numeral 1 indicates a pressurized flexible insulator tube in which mercury 2 is sealed. A pair of electrodes 3a and 3b are introduced into the insulator tube 1 from above. The mercury 2 is always maintained at a liquid level that does not contact the pair of electrodes 3a and 3b (when not driven).

On the other hand, FIG. 2 is a diagram showing an example of an electrostrictive porcelain tube. The inner diameter of the electrostrictive porcelain tube 5 is set to almost match the outer diameter of the insulator tube 1, and electrodes 5a and 5b are provided on the outer periphery of the electrostrictive porcelain tube 5, which are divided in the axial direction (vertical direction). is formed, and an electrode 5c provided on the inner periphery of the electrostrictive porcelain tube 5 is also formed.

FIG. 3 is a cross-sectional view of the electrostrictive porcelain tube 5 with the insulator tube 1 attached thereto. To drive the electrostrictive porcelain tube, lead wires 6a, 6 are connected from the respective electrodes 5a, 5b, 5c, respectively.
b and 6c are connected to form terminals E, F, and G. Then, power supply V ₁ is applied to terminal E, power supply V ₂ is applied to terminal F,
And connect it to G as a common terminal. In this case, the power source V ₁ and the power source V ₂ are AC power sources with a phase shift of 90° from each other. Note that the power supply V ₁ and the power supply V ₂ can also be separated from a single power supply using a circuit device. Electrostrictive porcelain generally generates strain proportional to the square of the voltage, so when an alternating current voltage is applied to terminals E and F, the electrostrictive porcelain tube 5 extends in the direction of extension (up and down) of the cylindrical axis and contracts in the centripetal direction. Therefore, the built-in insulator tube 1 is tightened. Therefore, the liquid level of mercury 2 inside insulator tube 1 rises. Electrostrictive porcelain tube 5
Since the contraction of the mercury 2 is proportional to the square of the voltage, the liquid level of the mercury 2 fluctuates up and down at twice the cycle of the input power.
In this case, the voltage applied to electrodes 5a and 5b is 90°
There is a phase shift, and when the tightening of the insulator tube 1 due to strain at the electrode 5a becomes zero, the tightening of the electrode 5b against the insulator tube 1 becomes maximum. Therefore, as long as the power is applied, the liquid level is always set higher than the standard mercury liquid level.
Therefore, by setting the lengths of the electrical contacts 3a and 3b so that the electrical contacts 3a and 3b come into contact with mercury at the mercury level when the electrostrictive porcelain tube is driven, an alternating current voltage is applied to the electrostrictive porcelain tube 5. As long as the voltage is applied, the electrodes 3a and 3b will be turned on.

Note that when a DC voltage is applied to the electrodes 5a, 5b, each electrode 5a, 5b tightens the insulator tube 1 at the same time, so the liquid level of the mercury 2 in the insulator tube 1 rises and the electrical contact of the electrical contacts 3a, 3b increases. A combination will be made. FIG. 4 is a diagram showing the relationship between the alternating current voltage applied to each electrode of the electrostrictive porcelain tube and the corresponding mercury liquid level. Figure A shows the AC voltage waveform applied to the electrode 5a, and Figure B shows changes in the mercury liquid level due to the application of this AC voltage. In addition, C in the same figure shows the electrode 5b.
This is an AC voltage waveform applied to the electrode 5a, and has a 90° phase with respect to the AC voltage applied to the electrode 5a.
Therefore, the mercury liquid level changes according to the alternating current waveform, as shown in FIG. Therefore, as shown in Figure E, by applying alternating current power to electrodes 5a and 5b at the same time, the mercury liquid level is maintained at the combined level of the liquid levels B and D in the figure. Therefore, in conventional electrostrictive relays, application of AC voltage causes bimorph vibration and cannot be used as a relay, whereas the relay of the present invention can turn on and off the power terminals even with continuous application of AC voltage. You can continue to turn it off.

As described above, according to the present invention, a pressurized flexible insulator tube containing a pair of electrical terminals and sealed with mercury, and a hole into which the insulator tube is inserted are formed on the inner surface of the hole. It consists of an electrostrictive porcelain tube with electrodes on the entire surface and upper and lower divided electrodes for connecting a DC power supply or an AC power supply with a phase shift of 90° on the outer surface.
The length of the electrical terminals was set so that the liquid surface of the mercury when voltage was applied to the divided electrodes would come into contact with the pair of electrical terminals, but would not come into contact with the pair of electrical terminals when no voltage was applied, so an electromagnetic relay was created. Not only does it have very little energy loss, which is the disadvantage of the electrostrictive relay, but it also allows the electrostrictive relay to use AC power, so it can be used even in environments where only AC power is available. A seed electrostrictive relay can be provided.

Also, according to the present invention, the divided electrodes have a 90° angle.
Even if a phase-shifted alternating current voltage is applied, the contraction action of the insulator tube based on the electrostriction of the electrostrictive porcelain tube can be continuously and stably performed, so that the electric terminals are not continuously in contact with or separated from each other. It becomes possible to maintain the tube state.

Furthermore, according to the present invention, by enclosing mercury in the insulator tube, the electrostrictive action of the electrostrictive porcelain tube is reliably transmitted to the insulator tube, thereby ensuring that the electric terminal is turned on and off. It can be tightened.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of an insulator tube, Fig. 2 is a diagram showing an example of an electrostrictive porcelain tube, and Fig. 3 A and B are cross-sectional views showing an example of the electrostrictive relay of the present invention and its operation. FIG. 4, a cross-sectional view for explanation, is a diagram showing the relationship between the alternating current voltage applied to the electrostrictive porcelain tube and the mercury liquid level in the insulator tube. 1...Insulator tube, 2...Mercury, 3a, 3b...
A pair of electrical terminals, 5... Electrostrictive porcelain tube, 5a, 5
b, 5c... Electrode.

Claims (1)

[Claim for Utility Model Registration] A pressurized flexible insulator tube with a pair of built-in electrical terminals and mercury sealed in it, a hole into which the insulator tube is inserted, and an electrode all over the inner surface of the hole. It consists of an electrostrictive porcelain tube with upper and lower divided electrodes connected to a DC power source or an AC power source with a phase shift of 90° on the outer surface of the tube. An electrostrictive relay characterized in that the length of the electric terminal is set so that the electric terminal contacts the pair of electric terminals and does not come into contact with the pair of electric terminals when no voltage is applied.