JPS61292834A - Piezo-electric relay - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a piezoelectric relay, and in particular, it is an object to obtain a piezoelectric relay that is highly efficient, has an increased holding force, and has stable operation.

"Prior Art" FIG. 4 is a diagram showing the basic structure and operating principle of a piezoelectric relay. Reference numeral 1 is a metal plate, and 2 and 2' are piezoelectric elements bonded to the metal plate 1, which constitutes a bimorph 9. 3 is a fixed part, 4 is a card made of an insulator, 5 is a movable spring, 6 is a fixed spring, and 5a and 6a are contacts.

7.8 is a current-carrying terminal.

The distortion of the piezoelectric elements 2, 21 obtained by applying a predetermined voltage to the current-carrying terminals 7, 8 generates displacement in the X or X' direction, thereby driving the movable spring 5 to open the contacts 5a, 6a. Configured to close.

However, when considering the dimensions and material constants of the piezoelectric material used to obtain the contact gap and contact force required for a relay, the problem is that it is not possible to obtain a compact and low-voltage operation, resulting in a large, inefficient relay. There was a point.

"Problems to be Solved by the Invention" In view of the above-mentioned problems, the present invention aims to provide a piezoelectric relay that is small in size, capable of low voltage operation, has high holding power, and has stable operation.

``Means for Solving the Problems'' Therefore, the present invention provides a bimorph in which at least a part of the bimorph is made up of a laminated piezoelectric element in which a plurality of piezoelectric elements are laminated adjacently so that the strain direction is uniform, and the other part is a fixed part. is a movable part that is displaced in a fixed direction, and a magnetic attraction force is applied to the movable part.

In other words, by applying a magnetic attraction force to the bimorph's displacement force, the lack of energy due to low-voltage driving can be compensated for, and the bimorph is constructed by laminating multiple piezoelectric elements adjacent to each other so that the strain direction is uniform. By doing this, the amount of displacement is the same, but the stiffness is increased and the difference between the load force when applying a positive voltage and a reverse voltage is increased, so that in combination with the above magnetic attraction force, the holding force becomes a dog. be.

"Embodiment" FIG. 1 shows an embodiment of a piezoelectric relay according to the present invention. 10
Reference numerals 11 and 12 indicate a metal substrate, and 11 and 12 indicate laminated piezoelectric elements in which a plurality of piezoelectric elements are laminated adjacent to each other so that the strain directions are equal to each other, and the bimorph 13 is constituted by these elements. 14 is a support provided on the base 15, and electrode plates 16, 17, 18, 19 are provided on the inner surface, and the bimorph 13 is fixed in a cantilever shape, and the electrode plates 16, 17 are fixed. , 18 and 19, voltage is applied to the bimorph 13. 20.21 is a current-carrying terminal. A card 22 made of an insulating magnet (for example, a plastic magnet) is fixed to the free end side of the bimorph 13. Reference numeral 23 denotes a U-shaped magnetic pole, which is fixed to the base 15 so that the card 22 can be moved between its opposite ends 23a and 23b. 24 is a movable spring, 25 is a fixed spring, and 24a.

25a is a contact point.

Next, FIG. 3(a) shows a comparison of the displacement-load characteristic curves between the bimorph 13 constructed of laminated piezoelectric elements 11 and 12 as in the present invention and the /(immorph 9 shown in FIG. 4).
This will be explained using (b). (,) is the case of the bimorph 9 shown in FIG. 4, and (b) is the case of the bimorph 1 according to the present invention.
This is the case of 3.

31.32 is a load characteristic curve of the bimorph itself, 33 and 34 are load characteristic curves when a positive voltage is applied to the bimorphs 9 and 13, and 35.36 is a load characteristic curve when a reverse voltage is applied, respectively.

x, , x'1 and x, , x' are the displacement amounts when the load force becomes "0" when voltage is applied, and x, and x
2 (x2 and x'2) are approximately the same value. Y and 2 are the load force difference (Y
<Z).

That is, the bimorph 13 according to the present invention has the characteristic that there is no difference in the amount of displacement due to voltage application, but the stiffness is small, and the difference in load force when applying a positive voltage and a reverse voltage is large. Therefore, within the range of the load force difference, the card 22 (magnet)
Since the magnetic attraction force by the magnetic poles 23 can be applied to the bimorph 13, the holding force can be increased.

Next, this will be explained in detail with reference to FIG. 2, which shows a displacement-load characteristic curve when spring load characteristics and magnetic attractive force are considered. 40 is a load characteristic curve due to the stiffness of the bimorph 13, 41 is a contact load characteristic curve due to the movable spring 24 and the fixed spring 25, and 42 is a load characteristic curve of the bimorph 13 and the movable spring 2.
4 and the spring load curve of the fixed spring 25, and 43 is the attractive force generated between the card 22 (magnet) and the magnetic pole 23. 44 and 45 are composite load characteristic curves when a positive voltage and a reverse voltage are applied to the bimorph 13.

As can be seen from the figure, bimorph 1 is created by applying voltage.
When the load force 43 reaches "0" (X3), the suction force 43 increases and the displacement is promoted. Therefore, high efficiency can be achieved.

Also, the card 22 (magnet) comes into contact with the magnetic pole 23 and the contact 24
In the closed state of a and 25a, the difference S between the suction force 43 and the combined load force of the bimorph 13 becomes the holding force. As described above, this holding force S increases as the difference in load force between positive and reverse voltages increases (it can be set), so as explained in FIG. It will be done.

Next, when a reverse voltage is applied, a load force difference R occurs between the reverse voltage and the composite load characteristic 45, and the bimorph 13 is restored.

FIG. 5 shows an example of an electrode in the fixed part of the bimorph 13, and the electrode 50 is provided with a border 51 to prevent migration of the electrode material on the ceramic due to the application of voltage. Coating with other insulating materials may also be considered.

In the present invention, a comparison was made between a so-called sandwich-shaped bimorph in which a plurality of piezoelectric elements with uniform strain directions are attached to both sides of a metal plate, whereas △ is a bimorph constructed by attaching them to only one side. Similar results are obtained when comparing with .

"Effects of the Invention" As explained above, according to the present invention, a bimorph is constructed by stacking a plurality of piezoelectric elements in which the strain direction is uniform, adjacent to each other, and magnetic attraction is applied to the movable part. Therefore, a stable piezoelectric relay with high efficiency and large holding force can be obtained.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the piezoelectric relay according to the present invention, Fig. 2 shows the same displacement-load characteristic curve, and Fig. 3 (a) and (b) show the displacement-load characteristic of the bimorph shown in Figs. 1 and 2. The curve comparison diagram, FIG. 4, is a diagram showing the basic structure and operating principle of a piezoelectric relay. FIG. 5 is an example of an electrode in the fixed part of the bimorph according to the present invention. 11.12... Laminated piezoelectric element, 22... Card (magnet), 23... Magnetic pole, 24... Movable spring, 25...
・Fixed spring.

Claims (1)

[Claims] At least a part of a bimorph constituted by a laminated piezoelectric element formed by stacking a plurality of piezoelectric elements adjacent to each other so that the strain direction is uniform is a fixed part and the other part is a movable part that is displaced in a fixed direction, and the movable part A piezoelectric relay characterized in that a magnetic attraction force is applied to the piezoelectric relay.