JPS62213029A - 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 try to save power by utilizing the distortion phenomenon of piezoelectric elements in relays.

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 6.
The configuration was as shown in the figure. In FIGS. 4 and 5, 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 support base 1. Shows a fixed contact mounted on.

The operation of the conventional piezoelectric relay configured as described above will be described below. Now, when an input voltage is applied from other control parts (not shown) such as a timer to the bimorph 2, which is made by pasting together the piezoelectric elements 2a and 2b, the bimorph 2 will move as shown by the two-dot chain line in FIG. curve like this. (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 is connected to the fixed point provided on the support base 1. 311. which is in contact with the contact 4 and wired to the movable contact 3 and the fixed contact 4, respectively. When another control part turns on and operates, and the input voltage applied to bimorph 2 is released, bimorph 2 returns to its original state and movable contact 3 and fixed contact 4 are separated. This will turn it into the OFF state and stop the operation of the control parts.

In addition, the present inventors have recently developed a piezoelectric relay as shown in FIGS.
We proposed a piezoelectric relay with a new configuration as shown in the figure. The piezoelectric relay proposed by the present inventors will be described below. In FIGS. 6 to 8, 5 is a case made of plastic or the like having a bottom surface and a protruding piece 5a at the top opening;
6 is a flat (square) piezoelectric bimorph made by bonding two piezoelectric elements, which curves in one direction when a voltage is applied. A plurality of piezoelectric bimorphs 6 are housed in the case 5 in a combination so as to alternately curve in opposite directions in a free state relative to the case 5. Reference numeral 7 designates a movable contact provided at the center of the upper surface of the piezoelectric morph 6a at the top end, and reference numeral 8 designates a fixed contact provided on the inner wall of the protruding piece 5a of the case 5.

FIG. 5, which describes the operation of the piezoelectric relay proposed by the present inventors and constructed as described above, shows a state in which the contacts 7 and 8 are in the OFF state before operation. In FIG. 6, an input voltage is applied to a plurality of piezoelectric bimorphs 6 (6a),
This shows the state when the piezoelectric bimorph 6 (6a) is bent. The bending of a piezoelectric bimorph when a voltage is applied is well known.
Since the principle of operation and wiring thereof are not directly related to the present invention, their explanation will be omitted. ), contacts 7 and 8 are in the QN state.

Problems to be Solved by the Invention In the former conventional configuration, as shown in FIG. and fixed contact 4
Depending on the voltage level applied to the device, abnormal discharge may occur, and due to the lack of dimensional margin during assembly, Bimorph 2 may malfunction from QN before bending, or OFF even after bending, which is an inconvenience. there were. In addition, if the total length of Bimorph 2 is made longer in order to increase the amount of displacement in two series, since it is a cantilever type, the strength of the piezoelectric element may cause cracks due to vibration etc., making it no longer functional. Met. Furthermore, when attaching and fixing the bimorph 2 to the support base 1, slight misalignment may cause the fourth
There is a possibility that a setting error may occur in the direction B shown in the figure and the direction C shown in FIG. 5, and the contacts 3 and 4 may not come into contact with each other, so that high precision in component dimensions is required. 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.

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 bimorphs, it is large and easy to assemble. The combination has the advantage of increasing the contact pressure during bending. However, since the shape of the piezoelectric bimorph is square, only a portion (one direction) of the bending force generated by the piezoelectric bimorph can be used, so internal stress distortion is likely to occur when bending. The current output (contact pressure) was also weak, and there was a problem in that reliable electrical switching could not be achieved.

Means for Solving the Problem In order to solve this problem, the present invention has a disc-shaped piezoelectric bimorph that curves in one direction when a voltage is applied to the case, each of which is free with respect to the case. A plurality of piezoelectric bimorphs are stacked and stored so that they are alternately curved in opposite directions, and the contacts are actuated by the spherical movement of the disc-shaped piezoelectric bimorph.

Effect: In addition to the advantages of the configuration proposed by the inventors earlier, this configuration also makes the internal stress strain uniform when bending because the piezoelectric bimorph has a disk shape, and the bending force also utilizes spherical curvature. Therefore, the contact pressure during bending also increases.

Embodiment FIGS. 1, 2 and 3 show a piezoelectric relay according to an embodiment of the present invention. In the figure, 7A-9 is a case made of plastic or the like having a bottom surface and a protruding piece 9a at the top opening, and 10 is a disk-shaped piezoelectric bimorph made by bonding two piezoelectric elements to which a voltage is applied. Then it curves in one direction. A plurality of piezoelectric bimorphs 10 are stored in the case 9 in a stacked form so as to curve alternately in opposite directions in a free state relative to the case 9. 11 is a movable contact provided at the center of the upper surface of the piezoelectric bimorph 10a at the top end, and 12 is a fixed contact provided on the inner wall of the protruding piece 9a of the case 9, facing the movable contact 11.

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

FIG. 1 shows the contacts 11 and 12 in the OFF state before operation. Figure 2 shows a plurality of disc-shaped piezoelectric plates (Imorph 9).
9a) shows the state when an input voltage is applied (similar to the conventional example, the bending of a piezoelectric bimorph due to voltage application is well known, so the explanation along with the wiring will be omitted). At this time, the piezoelectric morphs 9 (9a) are combined so that they alternately curve in opposite directions as described above, and an input voltage is applied to the piezoelectric morphs 9 (91L). As a result, the piezoelectric bimorph 9 (9a) curves as shown in FIG. 2, the movable contact 11 and the fixed contact 12 come into contact, and when the input voltage applied to the piezoelectric bimorph 9 (91L) is released, the piezoelectric bimorph 9 (91L) is bent. The bimorph 9 (9J) returns to its original state as shown in FIG. 1, and the movable contact 11 and fixed contact 12 are separated and turned OFF.

In addition, in the above embodiment, the case where all the piezoelectric bimorphs were made the same thickness was explained, but this does not necessarily mean that the piezoelectric bimorphs have the same size, and furthermore, piezoelectric bimorphs made of different materials It may also be configured by combining.

Effects of the Invention As described above, according to the present invention, a plurality of disc-shaped piezoelectric bimorphs are combined and housed in a case so that each piezoelectric bimorph is curved in opposite directions alternately, and a piezoelectric bimorph is placed at the top end of the piezoelectric bimorph. By having a relay contact, it is possible to provide a displacement equal to the number of piezoelectric bimorphs combined, and with regard to weather resistance such as vibration and temperature, the displacement is large, so natural distortion due to vibration etc. is absorbed, ensuring reliable opening and closing of the contacts and is highly reliable. However, reliable contact pressure can be maintained by setting the distance between the contacts to be slightly smaller than the bending ability of the piezoelectric bimorph. Furthermore, since the flat piezoelectric bimorph is freely incorporated into the case, assembly is simplified and assembly dimensions are stabilized (variation due to installation is prevented). By using a disc-shaped piezoelectric bimorph, the amount of displacement is the same as that of a rectangular piezoelectric bimorph, and the bending force can be increased, so that reliable contact pressure can be maintained. Furthermore, since it is held on the entire outer periphery during bending (spherical curvature), the internal stress is made uniform 9 and the operating strength is improved. It is a configuration that can solve all the problems, and has extremely high practical value.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the assembled state of a piezoelectric relay according to an embodiment of the present invention before operation (OFF state) on page 10, and Fig. 2 is a sectional view showing the assembled state during the same operation (0, N state). , Fig. 3 is a plan view of Fig. 2, Fig. 4 is a configuration diagram showing a conventional piezoelectric relay, Fig. 5 is a plan view of the same, and Fig. 6 shows the operation of the piezoelectric relay previously proposed by the present inventors. FIG. 7 is a cross-sectional view showing the assembled state in the previous (OFF state), FIG. 7 is a cross-sectional view showing the assembled state during the same operation (ON state), and FIG. 8 is a plan view of FIG. 9...Case, 10...Piezoelectric bimorph, 1
0a...Piezoelectric bimorph at the top end, 11...
...Movable contact, 12...Fixed contact. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4 Figure 5?

Claims (1)

[Claims] A plurality of disk-shaped piezoelectric bimorphs that curve in one direction when a voltage is applied are stacked and stored in a case so that each piezoelectric bimorph alternately curves in the opposite direction while being free with respect to the case. A piezoelectric relay whose contacts are activated by the spherical curvature of a plate-shaped piezoelectric bimorph.