JPS62115623A - 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 uses a piezoelectric unimorph or piezoelectric bimorph as a movable piece to open and close mechanical contacts.

(Prior art) In a conventional piezoelectric relay, a linear strip made of piezoelectric unimorph or piezoelectric bimorph is attached in the form of a cantilever, a movable contact is provided on the free end side of the tip, and a fixed contact is attached to the movable contact. They are placed opposite each other. An input signal is applied to the electrodes of the piezoelectric unimorph or piezoelectric bimorph to bend the cantilever and bring the movable contact at the tip into contact with the fixed contact.

This type of piezoelectric relay has a very high input impedance, so it has the characteristic that mechanical contacts can be opened and closed with a small amount of electric power.

(Problems to be solved by the invention) However, in the conventional piezoelectric relay with a cantilever structure,
The displacement of the movable contact cannot be made very large, so the contact pressure is low, and there are drawbacks such as a tendency to malfunction due to vibration. If the quality of the cantilever beam is increased, the amount of displacement of the contact can be increased, but in order to obtain the necessary large amount of displacement, the outer diameter of the relay becomes extremely large.

This invention was developed in view of the above-mentioned conventional problems, and therefore it is possible to increase the variation of the movable contact without increasing the outer diameter of the relay, and to obtain a large contact pressure.゛The aim is to provide the market.

(Means for Solving the Problems) Therefore, in the present invention, a spiral movable piece is used, which is formed by forming a band-shaped body made of a piezoelectric unimorph or a piezoelectric bimorph so that its planar shape forms a spiral in the thickness direction. One end of this movable piece was fixed, a movable contact was provided at the thin end, and a fixed contact was disposed opposite to the movable contact.

(Function) The spiral movable piece can have a very long overall length even if its overall external dimensions are small. Therefore, the amount of displacement of the movable contact at the tip becomes very large.

(Embodiment) FIG. 1 is a plan view of a spiral movable piece 10 used in a piezoelectric relay according to an embodiment of the present invention, viewed in the thickness direction.

The spiral movable piece 10 is made of a piezoelectric unimorph or piezoelectric bimorph having a laminated structure in the thickness direction, and is formed into a spiral band-like body having a width that is relatively wide relative to the thickness. Such a spirally shaped piezoelectric unimorph or piezoelectric bimorph can be made by etching or laser processing, for example.

The outer peripheral end of the spiral movable piece 10 is fixed to a fixed block 12 and fixed to a relay structure (not shown). The tip on the inner circumferential side of the spiral movable piece 10 is a free end, and a movable contact 14 made of Tsukuri R is fixed to the upper surface portion of the free end.

As shown in FIG. 2, a fixed contact 18 attached to a fixed member 16 fixed to the relay structure is arranged directly above the movable contact 14.

When no voltage is applied to the electrodes of the spiral movable piece 10 (lead wires are drawn out from the fixed block 12), the spiral movable piece 10 is included in almost the same plane; The movable contact 14 is separated from the fixed contact 18 by a predetermined distance.

When a predetermined DC voltage is applied to the electrodes of the piezoelectric unimorph or piezoelectric bimorph forming the spiral movable piece 10, piezoelectric deformation occurs, and the inner peripheral end side of the spiral movable piece 10 moves in a direction perpendicular to the plane of the paper in FIG. Transform to the front. That is, as shown by arrow a in FIG. 2, the tip portion having the movable contact 14 is deformed so as to be lifted upward. This deformation brings the movable contact 14 into contact with the fixed contact 18.

(Effects of the Invention) As explained above in detail, the piezoelectric relay according to the present invention is formed by forming a strip of piezoelectric unimorph or piezoelectric bimorph so that its planar shape when viewed in the thickness direction forms a spiral shape. Since it uses a spiral movable piece, even if the outer diameter of the structure is small, the total length of the spiral movable piece can be very long, and therefore the movable contact provided at the tip of this movable piece can be bent. becomes very large. Furthermore, since the movable piece is a spiral strip and there is a difference in effective length on both sides of the strip, the strip is twisted when a DC voltage is applied. As a result, the contact pressure can be increased and the piezoelectric relay has excellent vibration resistance, resulting in a highly reliable piezoelectric relay.

[Brief explanation of drawings]

FIG. 1 is a plan view of a spiral movable piece according to an embodiment of the present invention, viewed in its thickness direction, and FIG. 2 is a schematic diagram of a piezoelectric relay using the same movable piece. 10...Movable spiral piece 12...Fixed block 14...Movable contact 16...
... Fixed member 18 ... Fixed contact

Claims (1)

[Claims] (1) A spiral movable piece is formed by forming a strip of piezoelectric unimorph or piezoelectric bimorph so that its planar shape when viewed in the thickness direction forms a spiral. One end of this movable piece is fixed, and the other end is fixed. A piezoelectric relay with a movable contact and a fixed contact placed opposite the movable contact.