JPS62237633A - 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 curvature 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.

Hereinafter, a conventional piezoelectric relay will be described with reference to the drawings. Conventionally, this type of piezoelectric relay has a structure as shown in FIGS. 3 and 4. In FIGS. 3 and 4, 1 is a support base that supports the bimorph 2 formed by pasting together piezoelectric elements 21L and 2b, 3 is a movable contact attached to the tip of the bimorph 2, and 4 is a support base that is 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, when an input voltage is applied from other control parts (not shown) such as a timer to the bimorph 2 formed by bonding the piezoelectric elements 2 & and 2b, the bimorph 2 will move 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 each
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 established. This will cause the parts to stop working.

In addition, the present inventors recently proposed a piezoelectric relay with a new configuration as shown in FIGS. 5 to 7.

The piezoelectric relay proposed by the present inventors will be described below. In FIGS. 6 and 7, 6 is a cylindrical case made of plastic or the like having a bottom surface and a protruding piece 6& at the top opening, and 6 is a disc-shaped case made of two disc-shaped piezoelectric elements bonded together. A piezoelectric bimorph that bends spherically in one direction when a voltage is applied.

A plurality of disc-shaped piezoelectric bimorphs 6 are housed in the cylindrical case 6 in a state in which they are free with respect to the cylindrical case 6, in the form of a combination so that the piezoelectric bimorphs 6 are alternately curved spherically in opposite directions. 7 is a movable contact provided at the center of the upper surface of the disc-shaped piezoelectric bimorph 6a at the top end, and 8 is a fixed contact provided on the inner wall of the protruding piece s'a of the cylindrical case 6.

The operation of the piezoelectric relay proposed by the present inventors having the above structure will be described below.

FIG. 6 shows the contacts 7 and 8 in the OFF state before operation. FIG. 6 shows a state when an input voltage is applied to a plurality of disc-shaped piezoelectric bimorphs 6 (6a) and the disc-shaped piezoelectric bimorph e (ea) is curved.
The spherical curvature caused by voltage application (1) is well known, and its operating principle and wiring are not directly related to the present invention, so their explanation will be omitted. ), contacts 7 and 8 are in the ON state. FIG. 7 shows a state in which the disk-shaped piezoelectric bimorph 6 (6a) is misaligned due to variations in the outer diameter.

Problems to be Solved by the Invention In the former conventional configuration, as shown in FIG. Fixed contact 4
Depending on the voltage level applied to the connector, abnormal discharge may occur, and due to lack of dimensional allowance during assembly, malfunctions such as Pi and Morph 2 turning on before bending or turning off even after bending may occur, which is inconvenient. there were. Furthermore, if the total length of Pi-Morph 2 is increased in order to increase the displacement described above, since it is a cantilevered type, cracks will occur due to vibration etc. 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, there may be a slight misalignment in the attachment as shown in Fig. 3.
direction, raise the set lotus in the C direction shown in Fig. 4, and connect the contact point 3.
and 4 may not come into contact with each other, requiring high component dimensional accuracy. Furthermore, the longer the piezoelectric bimorph 2 is made in order to increase the number of displacements, the smaller 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 the amount of displacement becomes large since it is the sum of the amounts of displacement of the combined disk-shaped piezoelectric bimorph, and it is easy to assemble. The advantage is that the combination increases the contact pressure when the spherical surface is curved.

However, since two disc-shaped piezoelectric elements are bonded together, variations in the outer diameter may cause them to shift as shown in Figure 7. This also increases the cost as misalignment is not allowed during bonding.Also, since the disc-shaped piezoelectric bimorphs are stacked one on top of the other, there is a risk of wear between the contact parts with the cylindrical case 6 due to vibration etc. There was a risk of cracking or cracking.

Means for Solving the Problem In order to solve this problem, the present invention includes a disk-shaped piezoelectric element and a disk-shaped metal plate having a larger diameter than the disk-shaped piezoelectric element in a cylindrical case. It has a structure in which a plurality of disc-shaped piezoelectric unimorphs made by pasting together are housed so that they can bend alternately in opposite directions in a free state.

Effect: With this configuration, in addition to the advantages of the configuration proposed by the present inventors, the outer diameter dimension of the spherically curved disk-shaped piezoelectric unimorph can be determined by the disk-shaped metal plate, and the accuracy can be increased. As a result, displacement of the disc-shaped piezoelectric unimorphs stacked and stored in the cylindrical case is reduced, and a constant amount of displacement can be maintained at all times.

Embodiment FIGS. 1 and 2 are assembly configuration diagrams showing a piezoelectric relay according to an embodiment of the present invention, and the same parts as in FIGS. 6 to 7 are given the same numbers. In FIGS. 1 and 2, reference numeral 9 denotes a plurality of disc-shaped piezoelectric actuators installed in a cylindrical case S in a free state relative to the cylindrical case 6 so as to be curved spherically in the direction of the upper end opening of the cylindrical case S. This is a disc-shaped piezoelectric unimorph made by bonding an element 1o and a disc-shaped metal plate 11 with a diameter larger than that of the disc-shaped piezoelectric element 1'O, and when a voltage is applied like the disc-shaped piezoelectric bimorph, it becomes spherical in one direction. It is curved. Here, the disc-shaped piezoelectric unimorphs 9 are housed so as to be spherically curved alternately in opposite directions, and the movable contact 7 is provided on the disc-shaped piezoelectric unimorph 9a located at the uppermost end. Other parts are shown in Figures 6 to 7 as described above.
Since the configuration is similar to that shown in the figure, the same reference numerals will be given and the explanation will be omitted. Here, FIG. 1 shows the OFF state before operation, and the second
The figure shows a disk-shaped piezoelectric unimorph 9 (9λ) with a spherically curved O
Indicates N state.

Effects of the Invention As described above, according to the present invention, there is provided a disk formed by laminating a disk-shaped piezoelectric element and a disk-shaped metal plate having a larger diameter than the disk-shaped piezoelectric element in a cylindrical case. A disc-shaped piezoelectric unimorph is created by storing a plurality of piezoelectric unimorphs in a free state and curving them in opposite directions alternately, and by providing a movable contact point that performs contact operation on the disc-shaped piezoelectric unimorph located at the top. The amount of displacement can be determined by the number of layers stacked together, and the outer diameter of each disc-shaped piezoelectric unimorph remains circular even if the bonding between the disc-shaped piezoelectric element and the disc-shaped metal plate is slightly misaligned. Since it is determined by a sheet metal plate, high dimensional accuracy can be easily obtained (by pressing, etc.), simplifying assembly and stabilizing assembly dimensions (preventing variations due to installation). Furthermore, the present invention provides a highly reliable piezoelectric relay that does not cause variations in position.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the assembled configuration of a piezoelectric relay according to an embodiment of the present invention before operation, FIG. 2 is a cross-sectional view showing the state during the same operation, and FIG. 3 is a configuration diagram showing a conventional piezoelectric relay. , 4th
5 is a cross-sectional view showing the piezoelectric relay previously proposed by the present inventors before operation, FIG. 6 is a cross-sectional view showing the same state during operation, and FIG. 7 is a plan view of the same. FIG. 7 is a cross-sectional view of a main part showing a state in which the disc-shaped piezoelectric bimorph is misaligned due to variations in the outer diameter. 5... Cylindrical case, 6a... Protruding piece, 7... Movable contact, 8... Fixed contact,
9...Disc-shaped piezoelectric unimorph, 9a...
- Disc-shaped piezoelectric unimorph at the top, 10...disc-shaped piezoelectric element, 11...disc-shaped metal plate. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2121 Figure 3 β Figure 4? Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] Inside a cylindrical case, a disk-shaped piezoelectric unimorph formed by pasting together a disk-shaped piezoelectric element and a disk-shaped metal plate with a larger diameter than the piezoelectric element is bent alternately in opposite directions in a free state. A piezoelectric relay is made up of a disc-shaped piezoelectric unimorph located at the top and a movable contact that performs contact operation.