JPS62243218A - Piezoelectric 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 FIELD OF INDUSTRIAL APPLICATION The present invention relates to a piezoelectric relay that is used as a relay circuit for various industrial electronic control devices and utilizes distortion caused by an electrical load on a piezoelectric element.

Conventional technology In recent years, electronic devices have become more and more power-saving, and conventional electromagnetic relay devices consume a lot of power.Recently, there has been a trend to utilize the distortion phenomenon of piezoelectric elements in relays to save power. I'm getting stronger. 2. A conventional piezoelectric relay will be described below with reference to the drawings. Conventionally, this type of piezoelectric relay has had a configuration as shown in FIG. In FIG. 2, 1 is a piezoelectric element, 2 is a metal deflection plate bonded to the piezoelectric element 1, 3 is a movable contact attached to the deflection plate 2,
Reference numeral 4 denotes a support base for supporting a piezoelectric unimorph composed of a piezoelectric element 1 and a deflection plate 2, and a fixed contact 6 is attached at a position facing the movable contact 3. Input electric wires 6a and 6b apply voltage to the piezoelectric element 1, and are directly connected to the deflection plate 2 and the piezoelectric element 1, respectively.

The operation of the conventional piezoelectric relay configured as described above will be described below. Now, piezoelectric element 1 and deflection plate 2
When a voltage is applied to the piezoelectric unimorph from the input wires 6a and 6b, the piezoelectric unimorph curves as shown by the two-dot chain line in FIG. 2 (this phenomenon is well known, and the principle itself is the invention; (The explanation is omitted as it is not directly related.)
.

At this time, the movable contact 3 provided on the deflection plate 2 comes into contact with the fixed contact 6 provided on the support base 4, and another control component (not shown) wired to the movable contact 3 and the fixed contact 6, respectively. turns ON and operates, and when the input voltage applied to the piezoelectric unimorph is released, the piezoelectric unimorph returns to its original state and the movable contact 3 and fixed contact 6 are separated and turned OFF.
If it becomes an FF state, the control parts will stop operating.

In addition, the present inventors recently proposed a piezoelectric relay with a new configuration as shown in FIG. 3 as a solution to the drawbacks of the conventional piezoelectric relay shown in FIG. 2.

The piezoelectric relay proposed by the present inventors will be described below. In Fig. 3, 7 is a case made of plastic or the like having a bottom surface and a protruding piece 7a at the upper end opening, 8 is a piezoelectric element, which is bonded to a metal deflection plate 9 having a larger diameter, and has a flat plate shape. A piezoelectric unimorph is formed, and when a voltage is applied, the piezoelectric element 8 curves to become a convex surface, and this piezoelectric unimorph is placed in the case 7 in the form of a combination of a plurality of piezoelectric unimorphs so that they alternately curve in opposite directions. It is stored in a free state. 10 is the piezoelectric element 8N at the top end
A movable contact 11 is provided at the center of the upper surface of the case 7, and a fixed contact 11 is provided on the inner wall of the projecting piece 7a of the case 7, facing the movable contact 1°. 121L and 12b are piezoelectric elements 8 (8
This is an input electric wire for applying voltage to a), and is directly connected to each deflection plate 9 and piezoelectric element 8 by soldering or the like.

The operation of the piezoelectric relay proposed by the present inventors having the above structure will be described below. FIG. 3 shows a state in which a voltage is applied to the piezoelectric unimorph, each curves alternately in opposite directions, and the movable contact 1o and the fixed contact 11 are in contact with each other.As with the conventional example, the bending phenomenon of the piezoelectric unimorph is well known, so it will be explained. omitted. ), the control parts (not shown) connected to contacts 1o and 11 are turned on, and when the applied voltage is released, the piezoelectric unimorph returns to a flat state and contacts 10 and 11 are separated and connected to each other. The control parts that have been removed will be in the OFF state.

Problems to be Solved by the Invention In the former conventional configuration, as shown in FIG.
The amount of displacement is only about several tens of microns, and depending on the voltage level applied to the movable contact 3 and fixed contact 6, abnormal discharge may occur, or there may be no dimensional margin during assembly.
Because the piezoelectric unimorph is fixed on a cantilever, the position of the movable contact 3 attached to the tip of the deflection plate 2 is extremely unstable in front and back, left and right, or up and down, and even during bending operation, the movable contact 3 and fixed contact 6 are This is inconvenient, as it causes malfunctions such as turning OFF or, conversely, turning ON even before bending. In addition, if the total length of the piezoelectric unimorph is set long in order to increase the amount of displacement, since it is a cantilever type, cracks may occur due to vibration etc. due to the strength of the piezoelectric element. (contact pressure) was also reduced, and reliable electrical switching could not be achieved, and in the worst case, the device could no longer function.

In addition, the latter configuration proposed by the present inventors eliminates the drawbacks of the former conventional example, and because the displacement amount is the sum of the displacement amounts of the combined piezoelectric unimorphs, it is large and easy to assemble. Since they are combined in a double-supported configuration, there is an advantage that the contact pressure during bending is also strong.

However, as a means of applying voltage to the piezoelectric element to bend the piezoelectric unimorph, one electrode was directly connected to the piezoelectric element by soldering or the like, so it was necessary to assemble the piezoelectric unimorph with input wires connected in advance. , disconnections or setting errors occur frequently,
The bending operation sometimes became unstable due to solder build-up during soldering. In addition, when soldering an input wire to a piezoelectric element, the piezoelectric element is heated, which deteriorates the characteristics of the piezoelectric element itself and significantly reduces the amount of bending (displacement). There was also an element of uncertainty in terms of performance.

Means for Solving the Problem In order to solve this problem, the present invention provides a piezoelectric unimorph made by laminating a metal plate and a piezoelectric element, each of which is alternately arranged so that when a voltage is applied, the surface of the piezoelectric element curves into a convex surface. A plurality of piezoelectric unimorphs are assembled so as to curve in opposite directions, and an electrode plate made of a metal plate is provided between the surfaces of the piezoelectric elements of the piezoelectric unimorph.

Operation With this configuration, in addition to the advantages of the configuration proposed by the present inventors, the voltage applied to the piezoelectric unimorph can be easily and reliably applied by providing an electrode plate between the piezoelectric element surfaces of the piezoelectric unimorph. During assembly, it is possible to apply voltage to two piezoelectric unimorphs at once, simply by inserting a flat electrode plate. In addition, since there is no soldering or other treatment on the piezoelectric element surface, the piezoelectric element surface maintains a uniform flat surface and repeats a stable and constant movement even when curved, and the piezoelectric element itself is not heated, so it is stable. A piezoelectric relay with characteristics can be obtained.

Embodiment FIG. 1 shows the operating state of a piezoelectric relay according to an embodiment of the present invention, and the same parts as in FIG. 3 are given the same numbers. In FIG. 1, 13 is an electrode plate made of a metal plate provided between the surfaces of the piezoelectric elements of the piezoelectric unimorph, 13 is an electrode plate made of a metal plate arranged at the top end, and one input electric wire 12b is connected to these electrodes. connected to plate 13.13a,
Moreover, the movable contact 1o is the electrode plate 13! It is installed in L.

The operation will be explained below with reference to FIG.

In FIG. 1, the input electric wire 12 connected to the deflection plate 9
When voltage is applied to the input wire 12b connected to the electrode plates 13 and 131L in contact with the piezoelectric element 8, the piezoelectric unimorph curves, and as in the conventional example, the curvature of the piezoelectric unimorph is well known and will not be described here. ), the movable contact 1o and the fixed contact 11 come into contact and turn on, and when the voltage application is removed, the movable contact 10 and the fixed contact 11 separate and turn off.

Effects of the Invention As described above, according to the present invention, by providing an electrode plate between the piezoelectric element surfaces of the piezoelectric unimorph, a voltage can be easily and reliably applied to the piezoelectric unimorph.
Even during assembly, it is possible to apply voltage to two piezoelectric elements facing each other by simply inserting a flat electrode plate into the piezoelectric element surface, and there is no possibility of disconnection of the input wire during assembly or due to bending. can be reliably prevented. In addition, since no soldering is performed on the surface of the piezoelectric element, the contact surface remains evenly flat when curved, allowing stable and constant operation to be repeated, making it highly reliable, and at the same time, heating due to solder does not occur. Therefore, variations due to deterioration of the characteristics of the piezoelectric element do not occur, and the practical value is extremely high, such as simplifying assembly by wiring and improving reliability of voltage application.

[Brief explanation of drawings]

FIG. 1 shows the operation of a piezoelectric relay according to an embodiment of the present invention (
FIG. 2 is a configuration diagram showing a conventional piezoelectric relay, and FIG. 3 is a cross-sectional view showing the assembled state of the piezoelectric relay proposed by the present inventors when it is in operation (ON state). FIG. 7... Case, 8... Piezoelectric element, 9.
・Bent metal plate (metal deflection plate), 1o...Curved rotating contact, 11...Fixed contact, 12&, 12b...
...Input wire, 13...First electrode plate, 131
L...Second electrode plate. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 7-S Figure 2 Figure 3 f

Claims (1)

[Claims] A case, and a flat metal plate and a piezoelectric element bonded together inside the case, and when a voltage is applied, the piezoelectric element surface curves into a convex surface, and the piezoelectric elements are in a free state such that they curve alternately in opposite directions. multiple piezoelectric unimorphs built in,
A piezoelectric relay comprising a first electrode plate made of a metal plate arranged between piezoelectric element surfaces of the combined piezoelectric unimorphs, and a movable contact provided on a second electrode plate arranged at the uppermost end.