JPH01112630A - Piezo relay - Google Patents

Abstract

PURPOSE:To increase the contact pressing force and shorten the drive time by using the longitudinal effect strain of piezo elements, and enlarging it with an enlarging mechanism consisting of a lever arm and a beam. CONSTITUTION:Lever arms 41, 42 are fixed to a base board 2 by supports 31, 32. A group of piezo elements 1 are fixed to these lever arms 41, 42 at the two ends through supports 33, 34, and impression of a voltage causes deformation in the direction shown 7 in the attached illustration as longitudinal direction of the group of piezo elements 1. Plate-shaped and slightly bent beams 61, 62 are installed between the left and right ends of lever arm. Movable contacts 81, 82 are arranged in the centers of the beams 61, 62, and opening/closing of the movable contacts 81, 82 with their mating fixed contacts 91, 92 shall be opposite according to whether voltage is impressed on the group of piezo elements 1 or not. A lever frame and beams constitute a displacement enlarging mechanism, and opening/closing of the contacts is surely and quickly made at the time of voltage impression on the group of piezo elements.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to piezoelectric relays.

[Conventional technology]

FIG. 5 is a block diagram of a conventional piezoelectric relay in which a bimorph vibrator utilizing a piezoelectric transverse effect is used to drive one contact.

The bimorph vibrator 10 is composed of two piezoelectric elements 11 bonded together by three electrodes 12, one end of which is fixed to a substrate 13, and the other end has two movable contacts 14. The fixed contact 15 is provided at one end of a lead spring plate 16 fixed to 73 & 13 at the other end facing the movable contact 14 . Further, a voltage input terminal 17 with electrodes 12 connected in parallel is provided.

When a voltage is applied to the voltage input terminal 17, the bimorph resonator 10 bends due to the piezoelectric transverse effect, and the negative movable contact 1
4 comes into contact with the opposing fixed contact 15, and an electric circuit (not shown) connected thereto is turned on. When the applied voltage is removed, the bimorph resonator 10 returns to the state before the application, and the electrical circuit becomes OFF.

(Problems to be solved by the invention) - The conventional piezoelectric relay described above uses the piezoelectric transverse effect to
Since the bimorph resonator is used directly to drive the movable contact, there are the following drawbacks.

(1) When voltage is applied to the bimorph oscillator, the energy conversion efficiency from electrical energy to mechanical energy due to the curvature of the bimorph oscillator due to the expansion and contraction of the two piezoelectric elements that make up the biself @ oscillator is as low as 7 to 8%. In addition, the pressing force when the movable contact and the fixed contact contact each other is as small as about 5 g.

(2) Furthermore, since the resonant frequency of the bimorph resonator is within a low range, the driving time is approximately 30 msec, which makes it difficult to control the on/off operation of electric circuits at high speed when multiplexed devices are used. Become.

(Means for Solving the Problems) A piezoelectric relay of the present invention includes a fixed contact, a piezoelectric element group in which piezoelectric elements are laminated, a movable contact provided opposite to the fixed contact, and the movable contact A pair of fixed drops, whose side surfaces are respectively connected to both end surfaces of the piezoelectric element group, support the beam at both ends, and transmit and bend the expansion and contraction of the piezoelectric element group to the piezoelectric beam. It has a lever arm.

[Effect]

In the present invention, piezoelectric elements that produce a longitudinal effect with high energy conversion efficiency are laminated to serve as a contact opening/closing driving body, and the strain caused by this driving body is increased by an expanding mechanism consisting of a lever and a beam. It is something.

As a result, the bimorph vibration using the conventional piezoelectric transverse effect is zero.
From the first child, the contact pressing force increased from 5 g to 150 g, and the stress generated by the piezoelectric drive body increased to 190 (8).The energy conversion efficiency also increased from 7 to 8% to 55% due to the expansion mechanism. The time is from 30 msec to 1
It is shortened to less than TrLsoc, and the opening and closing of two or more electric circuits can be controlled at high speed.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a front view showing an embodiment of the piezoelectric appliance of the present invention.

A pair of lever arms 41 and 42 are fixed to opposite side surfaces of the substrate 2 by support parts 31 and 32, and both end faces of the piezoelectric element group 1 in which piezoelectric elements are laminated are attached to the support parts. It is fixed by 33°34. Plate-shaped and slightly curved beams 61 and 62 are supported between the lever arms 41 and 42, and movable contacts 5+ and 52 are attached to the center portions of the beams 6+ and 62, respectively. The movable contacts 5+ and 52 are provided with opposing fixed contacts 'lJ+ and 92, respectively.

These veneers 2. Support part 3+, 32.33.

34, the lever arms 41, 42, and the beams 61, 62 can be manufactured by a press processing method or a wire cutting method, and can be manufactured at low cost using a material with spring properties.

Furthermore, the piezoelectric element group 1 and the lever arms 4+, 42 are connected by thermosetting resin via the support portions 33, 34, and the lever arms 4+, 42 and the beams 61, 62 are joined by spot welding. The piezoelectric element group 1 is a laminate made up of a plurality of flat plate-shaped materials such as lead zirconate ditanate (PZR) on which electrodes are provided. 1a rules are alternated, and external electrodes (not shown) are provided on opposing sides.

Next, the operation of this embodiment will be explained. In the initial state before voltage is applied to the piezoelectric element group 1, as shown in the figure, the movable contact 52 is in contact with the fixed contact 92, and the movable contact 51 is in a non-contact state with the fixed contact 91.

When a voltage is applied to the piezoelectric element gY1 in this state, each piezoelectric element expands, and due to the added extension 7 of the piezoelectric element group 1, the lever arms 4+', 42 are moved to the support parts 3+, 32.
It rotates around the fulcrum, and the extension 7 is expanded at its tip. Then, axial compression and tension carts act on the beams 61 and 62 whose ends are sandwiched and supported between the lever arms 41 and 42, respectively, and the beams 61 are further deflected in a direction 81 perpendicular to the axial direction, causing the dye 62 The center portion moves in the direction of 82, and the lζ deflection becomes smaller. Due to this deflection of the beams 6+ and 62, the movable contact 51 comes into contact with the fixed contact 91, the movable contact 52 separates from the fixed contact 92, and the electrical circuits (not shown) connected thereto are turned on and off, respectively. It goes without saying that when the applied voltage is removed, the piezoelectric element WT1 returns to the state shown in FIG. 1 before the application of voltage.

FIG. 2 is a perspective view of a second embodiment of the piezoelectric relay of the present invention. In this embodiment, the orientation of the beam 6 is changed by 90° with respect to the axial direction compared to the first embodiment, and accordingly, the orientations of the fixed contacts 91, 92 and the movable contacts 5+, 52 are also changed. has been changed.

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

In this embodiment, as compared to the first embodiment, the piezoelectric element group 1 is provided parallel to the lever arms 4+, /I2, and is fixed to the substrate 2.

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

In this example, compared to the example shown in FIG.
The relative positions of the piezoelectric element 1!71 and the substrate 2 have been changed.

In the piezoelectric relay shown in Fig. 1, the movable contacts 51 and 52 move 0.3 mm to the fixed contacts 9+ and 92, and
It generates a contact pressing force of g, reaches an energy conversion efficiency of 55%, and the resonance frequency shifts to a high frequency range of 4 to 1 z, expanding the movable frequency range.

〔Effect of the invention〕

As explained above, the present invention stacks piezoelectric elements that produce longitudinal effect strain with high energy conversion efficiency, and
By incorporating a piezoelectric driver as a J source, increasing the strain field generated by this piezoelectric driver using a lever arm, and moving the movable contact by the deflection of the beam, the contact pressing force increases and the resonance frequency shifts to a high frequency range. By moving,
The driving time is shortened, and the on/off operation of two or more electric circuits can be controlled at high speed.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the piezoelectric relay of the present invention;
2, 3, and 4 are respectively a perspective view of the second embodiment of the present invention, a front view of the third embodiment, and a front view of the fourth embodiment. 'It is a cross-sectional side view of a heavy condensation appliance. 1... Piezoelectric element group, 2... Substrate, 31-34
...Support part, 4+, 42...Lever arm, 51.52...Movable contact, 6+, 62...Beam, 7...Pressure 7 [Extension of i-element group 1, 8... Direction of deflection, 9+, 92...Fixed contact. Patent applicant: NEC Corporation Representative: Susumu Uchihara, patent attorney 1 Figure 2

Claims (1)

[Scope of Claims] A fixed contact, a piezoelectric element group in which piezoelectric elements are laminated, a movable contact provided opposite to the fixed contact, a beam to which the movable contact is fixed, and the piezoelectric element A piezoelectric relay comprising: a pair of lever arms having side surfaces connected to both end surfaces of the group, supporting the beam at both ends, transmitting expansion and contraction of the piezoelectric element group to the beam, and causing the beam to deflect.