JPS62211824A - 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, etc., and utilizes a bending action caused by an electrical load on a piezoelectric element.

Conventional technology In recent years, electronic devices have become more power efficient, and conventional electromagnetic relay devices consume a lot of power.
There is a growing trend to utilize the distortion phenomenon of piezoelectric elements in relays to save power.

Hereinafter, a conventional piezoelectric relay will be described with reference to the drawings. Conventionally, this type of piezoelectric relay is shown in FIGS. 4 and 5.
The configuration was as shown in the figure. In FIGS. 4 and 6, 1 is a support base that supports a bimorph 2 formed by pasting together piezoelectric elements 2a and 2b, 3 is a movable contact attached to the tip of the bimorph 2, and 4 is a movable contact attached to the support base 1. A fixed contact is shown.

The operation of the conventional piezoelectric relay configured as described above will be described below. Now piezoelectric element 2! When an input voltage is applied to the bimorph 2 formed by pasting L and 2b together from other side leg components (not shown) such as a timer, the bimorph 2 curves as shown by the two-dot chain line in FIG. (This phenomenon is well known and the principle itself is not directly related to the present invention, so the explanation along with the wiring will be omitted.)

At this time, the movable contact 3 provided at the tip of the bimorph 2 comes into contact with the fixed contact 4 provided on the support base 1, and another control component wired to the movable contact 3 and the fixed contact 4 respectively turns ON.
When the input voltage applied to the bimorph 2 is released, the bimorph 2 returns to its original state, the movable contact 3 and the fixed contact 4 are separated, and the OFF state is reached, causing the control parts to become OFF. It will stop working.

Problems to be Solved by the Invention In such a conventional configuration, as shown in FIG. Depending on the voltage level applied to the contact 4, an abnormal discharge may occur, and there is no dimensional allowance during assembly, so the bimorph 2 is turned ON before it is bent.

Or, even if it is bent, a malfunction such as turning off occurs, which is inconvenient. Furthermore, if the overall length of the bimorph 2 is increased in order to increase the amount of displacement described above, since it is a cantilevered type, cracks will occur due to vibrations due to the strength of the piezoelectric element, and it will no longer function properly. Furthermore, when attaching and fixing the bimorph 2 to the support base 1, slight misalignment may cause setting errors in the B direction shown in FIG. 4 and the C direction shown in FIG. 4 may not come into contact with each other, requiring high component dimensional accuracy. Furthermore, the longer the piezoelectric bimorph is made to increase the amount of displacement, the lower the pressure at the time of bending (contact pressure) becomes, and reliable electrical switching cannot be achieved.

Means for Solving the Problem In order to solve this problem, the present invention includes piezoelectric bimorphs that are flat in a case and curve in one direction when a voltage is applied, each in a free state with respect to the case. A plurality of piezoelectric bimorphs are housed in a combination so as to curve alternately in the curvature direction, and a movable contact for contact operation is provided on the piezoelectric bimorph located at the uppermost end.

Effect With this configuration, the amount of displacement increases because it is the sum of the amounts of displacement of the piezoelectric bimorphs that are combined, and since the flat bimorph is stored in the case in a free state during assembly, errors due to assembly and contact points Variations in position are also eliminated, the strength is stable and strong, and the contact pressure during bending is also increased due to the combination.

Embodiment FIGS. 1, 2 and 3 show a piezoelectric relay according to an embodiment of the present invention. In the figure, 6 is a case made of plastic or the like that has a bottom surface and a protruding piece 51L at the top opening, and 6 is a flat piezoelectric bimorph made by bonding two piezoelectric elements, which curves in one direction when a voltage is applied. do. A plurality of piezoelectric bimorphs 6 are housed in the case 6 in a combination so as to alternately curve in opposite directions, free with respect to the case 5. Reference numeral 7 indicates a movable contact provided at the center of the upper surface of the piezoelectric bimorph 6iL at the top end, and 8 indicates a fixed contact provided on the inner wall of the protruding piece 51L of the case 5, facing the movable contact 7.

The operation will be explained below with reference to the drawings.

FIG. 1 shows the contacts 7 and 8 in the OFF state before operation. Figure 2 shows the ON state when an input voltage is applied to a plurality of piezoelectric bimorphs 6 (62L) (similar to the conventional example, the bending due to voltage application to piezoelectric bimorphs is well known, so the explanation along with the wiring will be omitted. ).

At this time, each of the piezoelectric bimorphs e (eh) is assembled so as to alternately curve in opposite directions as described above, and the amount of displacement per piezoelectric bimorph 6 (6a) at this time is is D as shown in FIG. 2, and the total displacement of the movable contacts 7 due to the combination is the displacement per one contact multiplied by the number of contacts (N) in combination. In addition, since there is a margin in the distance E between the contacts shown in FIG. , it becomes possible to set the contact pressure of the contacts 7 and 8 that perform the contact operation with a margin.

Next, an example of the contact pressure and displacement levels in the embodiment of the present invention and the conventional example are shown in the table below.

Here, the embodiment of the present invention is a combination of eight piezoelectric bimorphs, and the material of the piezoelectric bimorphs, the size of each piezoelectric bimorph, etc. are all the same, and the applied voltage was also measured under the same conditions. .

In addition, in the above embodiment shown in FIGS. 1 to 3,
Although the case where all the piezoelectric bimorphs are the same size has been described, in the present invention, the piezoelectric bimorphs do not necessarily have to be the same size, and there is no problem in constructing the piezoelectric bimorphs by combining a plurality of piezoelectric bimorphs made of different materials. It is.

Effects of the Invention As described above, according to the present invention, a plurality of flat piezoelectric bimorphs are combined and housed in a case so that each piezoelectric bimorph is curved in opposite directions alternately, and a relay contact is provided at the top end of the piezoelectric bimorph. By having this, it is possible to provide a displacement equal to the number of piezoelectric bimorphs combined, and vibration and
Regarding weather resistance performance such as temperature, since the amount of displacement is large, natural forces caused by vibration etc. are absorbed, so reliable opening/closing of the contacts is realized and is highly reliable. Further, by setting the distance between the contacts to be slightly smaller than the bending ability of the piezoelectric bimorph, reliable contact pressure can be maintained. Furthermore, since the flat piezoelectric bimorph is freely incorporated into the case, assembly is simplified and assembly dimensions are stabilized (preventing variations due to installation), and all problems of the conventional structure can be solved. , its practical value is extremely high.

[Brief explanation of drawings]

FIG. 1 shows a piezoelectric relay according to an embodiment of the present invention before operation (
Figure 2 is a cross-sectional view showing the assembled state in the same operation (ON state), Figure 3 is a plan view of the same, and Figure 4 is a configuration diagram showing a conventional piezoelectric relay. , FIG. 5 is a plan view of the same. 5...Case, 6...Piezoelectric bimorph, 6a...Piezoelectric bimorph at the top end, 7...
...Movable contact, 8...Fixed contact. Figure 1 Figure 3 χ Figure 4 β Figure 5?

Claims (1)

[Claims] A plurality of flat piezoelectric bimorphs that curve in one direction when a voltage is applied are housed in the case so that each piezoelectric bimorph alternately curves in the opposite direction while being free with respect to the case. A piezoelectric relay that has a movable contact that performs contact operation on a positioned piezoelectric bimorph.