JPH04169026A - Piezoelectric relay - Google Patents

Abstract

PURPOSE:To enable make and break of great electric power without using a displacement enlarging mechanism by jumping a permanent magnet with laminated piezoelectric actuators and moving to another end to hold the contact between fixed contacts and moving contacts with the permanent magnet and magnetic attraction force between powerful magnetic substances arranged behind the fixed contacts. CONSTITUTION:A pair of laminated piezoelectric actuators 1 are arranged opposite to each other at a preset space at both ends of an insulating case 6, a pair of soft powerful magnetic substances 2 are arranged on respective planes opposite to the laminated piezoelectric actuators 1 via insulating plates 10, fixed contacts 3A, 3B are provided opposite to each other inside the soft powerful magnetic substances 2, moving contacts 4A, 4B are provided at positions opposite to the fixed contacts 3A, 3B, and a permanent magnet 5 is arranged in a space between both fixed contacts 3A, 3B together with a holder 13 which holds a lead terminal 7 passing through the opening 8 of the case 6. The permanent magnet 5 is jumped by the impulse-driven laminated piezoelectric actuators 1 and moved to another end to hold the contact between the fixed contacts 3A, 3B and the moving contacts 4A, 4B with magnetic attraction force between the powerful magnetic substances 2. It is thus possible to perform make and break of great electric power without using a displacement enlarging mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a piezoelectric relay, and particularly to a piezoelectric relay using a laminated piezoelectric actuator as a driving source.

[Conventional technology]

Conventionally, this type of piezoelectric relay has a displacement amplification mechanism that uses the principle of leverage to combine minute displacements of laminated piezoelectric actuators made of multiple thin layers of PZT (crystals of lead titanate, zirconium titanate, and barium titanate). It is a structure that expands and drives the movable contact.

[Problem to be solved by the invention]

The conventional piezoelectric relay described above uses a laminated piezoelectric actuator in which a plurality of thin layers of PZT or the like are laminated as a driving source. This laminated piezoelectric actuator can generate a large force of several kgf when a rated drive voltage is applied, but the amount of displacement is extremely small, such as several μm. Therefore, when used in a practical relay, a displacement magnification mechanism with high magnification based on the principle of leverage is required.

However, as these displacement magnification mechanisms increase their magnification ratio, their dimensions increase, they are greatly affected by thermal expansion, and their structures become complicated, making them unsuitable for switching large amounts of power and reducing productivity. It has the disadvantage of being extremely bad.

An object of the present invention is to provide a piezoelectric relay that enables switching of large electric power without using such a displacement amplification mechanism.

[Means to solve the problem]

The piezoelectric relay of the present invention includes: a cylindrical or tub-shaped insulating casing with an opening formed at the bottom; a pair of laminated piezoelectric actuators disposed oppositely at both ends of the insulating casing with a certain distance therebetween; A pair of soft ferromagnetic bodies arranged on opposing surfaces of each of the laminated piezoelectric actuators with an insulating plate interposed therebetween, fixed contacts provided inside the soft ferromagnetic bodies to face each other, and positions facing the fixed contacts. a permanent magnet provided with a movable contact and a lead terminal passing through an opening of the housing together with a holder, and the permanent magnet disposed in a space between both fixed contacts is driven by impulse It is caused to jump and move to the other end by a laminated piezoelectric actuator, and the contact between the fixed contact and the movable contact is maintained by the magnetic attraction force between the permanent magnet and the ferromagnetic body disposed behind the fixed contact. It is configured as follows.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a piezoelectric relay showing a first embodiment of the present invention.

As shown in FIG. 1, in principle, this embodiment uses PZT (lead titanate, zirconium titanate,
A pair of laminated piezoelectric actuators 1 are used in which a plurality of thin layers such as titanate (valium crystal) are laminated. This laminated piezoelectric actuator 1 can generate a displacement of several micrometers and a force of several kgf by applying the rated drive voltage. Therefore, when this laminated piezoelectric actuator 1 is impulse-excited, it instantaneously generates a large force and a large force. A displacement can be generated and a member placed on the laminated piezoelectric actuator 1 can be caused to jump. The present embodiment takes advantage of this phenomenon, and includes a multilayer piezoelectric actuator 1 arranged at both ends of a hollow cylindrical housing 6 with a certain space between them, and a permanent magnet 5 as a movable object that can freely move in space. , the permanent magnet 5 as a movable object that was in contact with the laminated piezoelectric actuator 1 is repelled toward the facing laminated piezoelectric actuator 1. At this time, the permanent magnet 5 as a movable object is fixed on the facing laminated piezoelectric actuator 1 by means such as magnetic attraction, and when a driving impulse voltage is applied to the facing laminated piezoelectric actuator 1, the permanent magnet 5 is thrown off to the surface of the original laminated piezoelectric actuator 1. In this way, the impulse '[
By applying pressure, the permanent magnet 5 can be caused to reciprocate.

Further, in this embodiment, fixed contacts 3A and 3B are connected to the gate terminals 9A and 9B, respectively, through the insulating plate 10 on the opposing surfaces of the pair of opposing laminated piezoelectric actuators 1.
is provided, while a holder 1 is attached to the permanent magnet 5 as a movable object.
If the movable contacts 4A and 4E are arranged facing each other along with the lead terminal 7 and the lead terminal 7, a switching relay function can be achieved. Note that the simplest structure can be achieved by using a ferromagnetic material as the holder 13 of the permanent magnet 5.

The details of this embodiment will be further explained below.

In this embodiment, a pair of laminated piezoelectric actuators 1 are arranged at both ends of a cylindrical or tub-shaped electrically insulating casing 6 at an appropriate distance apart, and a permanent magnet 5 as an armature member that can move freely in this space. When an impulse voltage is applied to the laminated piezoelectric actuator 1 in one position, the laminated piezoelectric actuator 1 rapidly expands. At that time, permanent magnet 5
When the permanent magnet 5 is in contact with any of the laminated piezoelectric actuators, the permanent magnet 5 is suddenly repelled and moves toward the opposing laminated piezoelectric actuator 1. Moreover, since the soft ferromagnetic materials 2 are arranged on the surfaces of the laminated piezoelectric actuator 1 with the insulating plates 10 in between, the permanent magnets 5 are held and stopped by the magnetic attraction force.

However, although the displacement of the laminated piezoelectric actuator 1 is as small as several micrometers, it generates a large force of several kgf, so by repelling the permanent magnet 5, it is possible to increase the displacement.

This embodiment makes use of this principle, and also installs fixed contacts 3A, 3B and movable contacts 4A, 4B as electrical contacts at both ends of a pair of laminated piezoelectric actuators 1 and permanent magnets 5, respectively, and creates a leat for fixed contacts. Terminal 9A, 9
If connected to the outside using the movable contact lead terminal 7 that moves within the opening 8 and E, an impulse-driven self-holding relay can be constructed. Note that both ends of the pair of laminated piezoelectric actuators 1 are laminated piezoelectric actuator terminals 11A, IIB, and 12A, respectively.

12B.

FIG. 2 is a sectional view of a piezoelectric relay showing a second embodiment of the present invention.

As shown in FIG. 2, in this embodiment, the soft ferromagnetic material 2 on the fixed side disposed in the cylindrical or tub-shaped electrically insulating housing 6 in the first embodiment described above is used as a permanent magnet. This is a self-holding type piezoelectric relay in which the permanent magnet 5, which is a movable object, is replaced with a soft ferromagnetic armature 15.

The only difference in the operation of such a piezoelectric relay is whether the permanent magnet 5 or the soft ferromagnetic material 15 is attracted.

FIG. 3 is a sectional view of a piezoelectric relay showing a third embodiment of the present invention.

As shown in FIG. 3, in this embodiment, the soft ferromagnetic material 2 placed inside the cylindrical or tub-shaped electrically insulating casing 6 in the first embodiment described above is taken out and electrically connected. This is a self-holding type piezoelectric relay disposed as a soft ferromagnetic material 16 on the outside upper part of an insulating casing 6.

The operation in this case is similar to the first embodiment, in which the permanent magnet 5 is a movable body.

FIG. 4 is a sectional view of a piezoelectric relay showing a fourth embodiment of the present invention.

As shown in FIG. 4, in this embodiment, the soft ferromagnetic material 16 in the third embodiment shown in FIG. The operation is the same as that of the third embodiment.

FIG. 5 is a sectional view of a piezoelectric relay showing a fifth embodiment of the present invention.

As shown in FIG. 5, this embodiment replaces a part of the cylindrical or tub-shaped electrically insulating housing 6 of the first embodiment with a conductor section 18, and also includes a permanent magnet that is a movable object. Movable contacts 4A, 4 arranged together with the holder 13 of 5
A current collector brush or a metal bearing 17 is provided which is electrically connected to B, and when the permanent magnet 5 is attracted, the metal bearing 19 slides along the inside of the conductor part 18 to establish electrical contact. This is a self-holding piezoelectric relay with a fixed structure.

FIG. 6 is a sectional view of a piezoelectric relay showing a sixth embodiment of the present invention.

As shown in FIG. 6, this embodiment is a self-retaining type in which the movable contact portion of the first to fifth embodiments described above is taken out to the outside of a cylindrical or tub-shaped electrically insulating casing 6. It is a piezoelectric relay. That is, the reed switch 20 as a movable contact is taken out to the outside, and the reed switch 5 is opened and closed by moving the permanent magnet 5.

FIG. 7 is a sectional view of a piezoelectric relay showing a seventh embodiment of the present invention.

As shown in FIG. 7, in this embodiment, the movable contact portion is taken out to the outside of the cylindrical or tub-shaped electrically insulating casing 6, and the soft ferromagnetic material 21 is placed as the contact point, similar to the sixth embodiment described above. This is a self-holding type piezoelectric relay placed between the housing 6 and the housing 6.

Moreover, since the opening 22 is formed in the soft ferromagnetic material 21 near the contact point of the reed switch 20, the permanent magnet 5
The range of operation and recovery of the reed switch 20 is sharply limited depending on the movement position of the reed switch 20.

Incidentally, the reed switch 20 in the sixth and seventh embodiments described above may be replaced with a mercury switch.

〔Effect of the invention〕

As explained above, the piezoelectric relay of the present invention does not require a conventional displacement amplification mechanism that requires a complicated mechanism and is largely affected by dimensional changes such as thermal expansion, and has a simple plunger structure. It is possible to realize a large contact gap and a large contact pressure, and has the effect of enabling high-power switching.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a piezoelectric relay showing a first embodiment of the present invention, and FIGS. 2 to 7 are cross-sectional views of piezoelectric relays showing second to seventh embodiments of the present invention, respectively. 6 ■・・・・・・Laminated piezoelectric actuator, 2・・・・・・
・Soft ferromagnetic material, 3A, 3B...Fixed contact, 4
A, 4B...Movable contact, 5, 14.17...
...Permanent magnet, 6...Housing, 7...Leat terminal for movable contact, 8...Opening, 9A, 9B
・・・・・・Lead terminal for fixed contact, lO・・・・・・
Insulating board, 11A, IIB, 12A, 12B...
Lead terminal for laminated piezoelectric actuator, 13...
・Metal holding body, 15, 16, 21... Soft ferromagnetic material, 18... Metal conductor part, 19...
・Current flange or metal bearing, 20...
...Reet switch, 22...Opening. Agent Patent Attorney Uchihara Ondai l Zuka 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A cylindrical or tub-shaped insulating casing with an opening formed at the bottom, and a pair of laminated piezoelectric actuators disposed facing each other at both ends of the insulating casing with a certain distance between them. a pair of soft ferromagnetic bodies disposed on opposing surfaces of each of the laminated piezoelectric actuators with an insulating plate interposed therebetween; a fixed contact provided opposite to each other inside the soft ferromagnetic body; and a fixed contact facing the fixed contact. a permanent magnet provided with a movable contact at a position and a lead terminal passing through an opening of the housing together with a holder, and the permanent magnet disposed in a space between both fixed contacts is driven by an impulse. The laminated piezoelectric actuator causes the contact to jump and move to the other end, and the fixed contact and the movable contact are maintained in contact by magnetic attraction between the permanent magnet and the ferromagnetic body disposed behind the fixed contact. A piezoelectric relay characterized by: 2. A piezoelectric relay characterized in that the soft ferromagnetic material and the permanent magnet according to claim 1 are replaced with a permanent magnet and a soft ferromagnetic material, respectively. 3. A cylindrical or tub-shaped insulating casing with an opening formed at the bottom, a pair of laminated piezoelectric actuators arranged oppositely at both ends of the insulating casing with a certain distance between them, and each of the laminated piezoelectric actuators. a permanent magnet, which is provided with a fixed contact placed oppositely on opposing surfaces of the housing with an insulator interposed therebetween, and a permanent magnet provided with a movable contact at a position opposite to the fixed contact and a lead terminal passing through an opening of the housing together with a holder; , a soft ferromagnetic material provided at a position where the fixed contacts are arranged and outside the insulating casing, and the laminated piezoelectric material is impulse driven to drive the permanent magnets arranged in the space between the fixed contacts. An actuator makes it jump and move to the other end,
A piezoelectric relay characterized in that contact between the fixed contact and the movable contact is maintained by magnetic attraction between the ferromagnetic bodies disposed outside the housing. 4. A piezoelectric relay characterized in that the soft ferromagnetic material and the permanent magnet according to claim 3 are replaced with a permanent magnet and a soft ferromagnetic material, respectively. 5. In the insulating casing according to claim 1, part or all of the periphery of the movable region of the permanent magnet is replaced with a conductor, and the permanent magnet and the current collector brush or metal bearing are brought into electrical contact with each other, and the contact portion is A piezoelectric relay characterized by being sealed. 6. A cylindrical or tub-shaped insulating casing, a pair of laminated piezoelectric actuators placed opposite each other at both ends of the insulating casing with a certain distance between them, and a pair of laminated piezoelectric actuators placed on opposing surfaces of each of the laminated piezoelectric actuators. a reed switch disposed outside the insulating casing as a fixed contact and a movable contact, and a permanent magnet disposed between the soft ferromagnetic bodies inside the insulating casing; A piezoelectric relay characterized in that the contacts of the reed switch are opened and closed by the movement of a permanent magnet. 7. The piezoelectric relay according to claim 6, wherein another soft ferromagnetic material having an opening around the contact portion of the reed switch is disposed along the insulating casing.