JPH04324982A - Piezoelectric element displacement magnifying mechanism - Google Patents

Abstract

PURPOSE:To enable a set of piezoelectric element displacement magnifying mechanism to output two outputs and to be reduced to half in size by a method wherein the intermediate part of a thin-plate beam linked to lever arms like a bridge is joined to a mounting board. CONSTITUTION:A pair of lever arms 3 disposed confronting each other is provided, and a thin plate beam 13 whose one end is fixed to the end of the lever arm 3 and other end is fixed to the end of the other lever arm 3 is provided to link the pair of lever arms 3 together like a bridge. A mounting base 4 links the pair of lever arms 3 together through the intermediary of pairs of hinges 2 and 5 which are provided protruding in opposite directions to the opposed side faces of it. The intermediate part of the beam 13 is fixed to the mounting base 4. By this setup, a set of magnifying mechanism is able to output two outputs and to be reduced to half in size.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element displacement amplifying mechanism for amplifying the displacement of a piezoelectric element as a driving source.

0002

2. Description of the Related Art A conventional piezoelectric element displacement magnifying mechanism (hereinafter referred to as the magnifying mechanism) will be explained with reference to FIG.

FIG. 4 shows an enlargement mechanism using a laminated piezoelectric element as a drive source that utilizes the longitudinal effect strain of the piezoelectric element, and the displacement of the piezoelectric element 1 is transmitted through a first hinge 2 to enlarge the 2-layer piezoelectric element. A book lever arm 3, a second hinge 5 connecting this lever arm 3 and the mounting board part 4, and a lever arm 3.
It consists of a beam 6, which serves as a displacement amplifying means, and is connected in a bridge shape by fastening rivets to the tip of the beam. Here, the distance from the center of the beam 6 to the mounting board portion 4 is referred to as beam height 7.

[0004] In order to assemble the enlargement mechanism having such a structure, first, the displacement enlargement fitting 8 is assembled, in which the mounting base plate 4, the two lever arms 3, the first hinge 2, and the second hinge 5 are integrated. and piezoelectric element 1 are prepared. The displacement magnifying fitting 8 is manufactured from a metal plate by wire cut electrical discharge machining or the like. Then, both ends of the piezoelectric element 1 are bonded to the first hinge 2 with an adhesive made of thermosetting resin. Next, prepare the beam 6 and the rivet 9, and
0 to the tip of the lever arm 3, the rivet 9 is passed through with the rivet hole 11 provided at the tip of the lever arm 3 and the rivet hole of the beam 6 overlapping, and the rivet 9 is pressed using a hydraulic press or the like. The enlarging mechanism is completed by molding to a predetermined size.

In the enlargement mechanism assembled in this manner, when a voltage is applied to the piezoelectric element 1, the displacement of the piezoelectric element 1 is transmitted to each lever arm 3 via the first hinge 2. The lever arm 3 uses the second hinge 5 as a fulcrum and expands the displacement at the tip of the lever arm 3 using the lever principle. Displacement in the longitudinal direction of the beam 6 is transmitted to both ends of the beam 6 connected in a bridge shape to the tip of the lever arm 3, and the beam 6 performs a well-known buckling motion, resulting in a maximum displacement of 12
occurs. When the applied voltage is reduced to zero volts, the displacement of the piezoelectric element 1 is restored, and the displacement of the beam 6 is also restored at the same time.

[0006]

[Problem to be Solved by the Invention] According to the structure of this conventional enlarging mechanism, only one output can be obtained from one set of enlarging mechanisms, and when two outputs are required, two enlarging mechanisms are combined in parallel. That will happen. Furthermore, when it is desired to obtain different maximum displacement amounts as outputs, enlargement mechanisms must be designed and combined for each maximum displacement amount. In other words, the conventional enlarging mechanism has the drawback that when two outputs are desired, not only is the enlarging mechanism large in size, but the cost is also high.

[0007]

[Means for Solving the Problems] The piezoelectric element displacement magnifying mechanism of the present invention includes a pair of lever arms placed opposite each other, one end of which is fixed to one end of one lever arm, and the other end of which is fixed to one end of the other lever arm. a thin plate-shaped beam that connects the respective lever arms in a bridge shape; and a mounting board that connects the pair of lever arms via a pair of hinges that protrude in opposite directions from a pair of opposing side surfaces; and a piezoelectric element that generates displacement due to piezoelectric effect, and the displacement generated by the piezoelectric element is transmitted to two lever arms, expanded by the lever principle using the hinge as a fulcrum, and transmitted to the beam, and the displacement generated by the piezoelectric element is transmitted to the beam. In the piezoelectric element displacement magnifying mechanism of the type that performs buckling motion, the intermediate portion of the beam is fixed to the mounting substrate portion.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of the invention.

In contrast to the beam 6 of the conventional expansion mechanism shown in FIG. 4, in which the fastening portions 10 are provided at only two locations at both ends of the beam 13 in this embodiment, the fastening portions 10 are provided at the intermediate portion of the beam 13. It also has a fastening part 10. Further, the mounting board portion 4 also has one rivet hole 11.

The method of assembling the beam 13 having the above-described structure to fabricate the expanding mechanism is the same as the method of assembling the conventional expanding mechanism described above, up to the point where both ends of the beam 13 are fastened with rivets. After that, the rivet hole provided at the center of the fastening part 10 in the middle part of the beam 13 and the rivet hole 11 of the mounting board part 4 are overlapped, and the rivet 9 is passed through.
The rivet 9 is molded to a predetermined size using a hydraulic press or the like to complete the expansion mechanism according to this embodiment.

When a voltage is applied to the piezoelectric element 1 of the enlarging mechanism having such a structure, the displacement is amplified at the tip of the lever arm 3, as in the conventional enlarging mechanism, and the beam 13 held between the lever arms 3 is expanded. Axial displacement is transmitted to both ends. Since the fastening portion 10 at the intermediate portion of the beam 13 is fixed, two maximum displacements 14 occur on both sides of the fastening portion 10 due to the buckling movement of the beam.

Next, in order to confirm the above, an enlarging mechanism according to this embodiment was manufactured, and the results of measuring the maximum displacement will be described. First, the longitudinal elastic modulus is 14.8×103
kg/mm2 of 42Ni-Fe material with a thickness of 4mm was machined using the wire-cut electric discharge machining method to form an outer diameter of 35mm x 3.
We manufactured a 0mm displacement magnification fitting. A piezoelectric element laminated with conventionally known lead zirconate titanate ceramics was adhered to this with an adhesive made of thermosetting resin (Amicon A-401). Then, after the adhesive has hardened,
The piezoelectric element attached to this displacement magnification fitting was polarized under the same polarization conditions as before. In addition, the beam, which has three fastening sections, was fastened with aluminum ribbed.

[0013] In the enlargement mechanism thus assembled, the beam heights 15 of the two beams between the intermediate fastening part and the both end fastening parts of the beams were both 6.05 mm. Further, when DC 150V was applied to this enlarging mechanism, the two maximum displacements of the beam were each 0.15 mm.

On the other hand, in order to obtain the same effect with a conventional magnifying mechanism that has only one output, two sets of magnifying mechanisms would be combined in parallel, and the shape would be 8 mm thick and 35 mm in outer diameter x 30 mm. Ta. That is, in this embodiment, by riveting the center part of the beam 13 to the mounting board part 4, two outputs can be obtained, and the product can be manufactured at 1/2 the size and cost compared to the conventional method. .

Next, a second embodiment of the present invention will be described. FIG. 2(a) is a perspective view showing a second embodiment of the present invention, and FIG. 2(b) is an enlarged sectional view taken along the line AA in FIG. 2(a).

In this embodiment, the displacement magnification fitting 8 has a laminated structure, unlike those in the conventional and first embodiments. The displacement magnifying fitting 8 is manufactured by press punching a thin metal plate (thickness 0.15 to 0.4 mm) made of a highly rigid metal material. , form a rectangular caulking part 16 by partially punching out a part of an arbitrary shape or half punching out the entire circumference, and stack the sheets one by one and sandwich them, and the frictional force of the cut surface of the protrusion of the caulking part 16 makes them adhere to each other. do.

Lever arm 3 of the enlargement mechanism according to this embodiment
A beam 13, which is the same as that in the first embodiment shown in FIG. 1, is fastened to the tip with a rivet 9. The rivet fastening method and operation in this embodiment are the same as in the first embodiment.

In the expansion mechanism according to this embodiment, 42Ni with a longitudinal elastic modulus of 14.8×103 kg/mm2 is used.
- When press punching a 0.4 mm thick Fe material, create a caulking part 16 by half punching the entire circumference of the square shape, one on the mounting board part 4, and two on each lever arm 3.
Form a spot and stack 10 sheets to a laminated thickness of 4 mm and an outer diameter of 35 mm.
A displacement magnification fitting 8 with a size of 30 mm was manufactured. Next, a beam 13 having the same shape and structure as the beam in the first embodiment was fastened to this displacement magnification fitting 8 with aluminum rivets 9. The heights of the two beams 15 in this layered structure expansion mechanism are each 6.05 mm, and the maximum displacements 14 are each 0.15 mm.
Met.

From the above results, it was confirmed that the same effects as in the first embodiment can be obtained in this embodiment as well.

Next, a third embodiment of the present invention will be explained. FIG. 3 is a perspective view showing a third embodiment of the invention.

The present embodiment is an enlargement mechanism having beams 13a and 13b having asymmetrical beam heights across a fastening portion 10 at the intermediate portion of the beams. The assembly method and operation when manufacturing the enlarging mechanism having the structure as described above are the same as those of the first embodiment and the conventional enlarging mechanism.

[0022] Also in the enlarging mechanism of the third embodiment, the first
Similarly to the example of 42Ni-Fe, the layer thickness was 4.
A displacement magnification fitting 8 with an outer diameter of 35 mm x 30 mm was manufactured, the piezoelectric element 1 was adhered to it, and a beam having an asymmetrical shape was fastened with rivets.

The beam heights 15a and 15b and the maximum displacements 14a and 14b are as follows.

Output 1; Beam height 5.8mm Maximum displacement 0
．． 16mm Output 2; Beam height 6.2mm Maximum displacement 0
．． 12 mm From the above results, according to this example, two maximum displacements of different sizes can be output by changing the heights of the two beams between the fastening part at the middle part of the beam and the fastening parts at both ends. It turns out that you can do it.

Furthermore, the same effects as in the first and second embodiments can be obtained in terms of size and cost.

[0026]

As described above, according to the present invention, two outputs can be obtained from one set of piezoelectric element enlarging mechanisms by connecting the intermediate portion of the beam to the mounting substrate portion. Furthermore, by making the beam heights of the respective beams different, it is also possible to obtain different maximum displacements.

Therefore, in the conventional piezoelectric element displacement amplifying mechanism, two piezoelectric element displacement amplifying mechanisms must be combined in parallel in order to obtain two outputs, resulting in a large size and high cost. On the other hand, with the piezoelectric element displacement magnifying mechanism of the present invention, the shape and cost can be halved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a piezoelectric element displacement magnification mechanism according to a first embodiment of the present invention.

FIG. 2 is a perspective view and a sectional view of a piezoelectric element displacement magnification mechanism according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a piezoelectric element displacement magnification mechanism according to a third embodiment of the present invention.

FIG. 4 is a perspective view of a conventional piezoelectric element displacement magnification mechanism.

[Explanation of symbols]

1 Piezoelectric element 2 First hinge 3 Lever arm 4 Mounting board part 5 Second hinge 6, 13, 13a, 13b Beam 7, 15, 15a, 15b Beam height 8 Displacement magnifying fitting 9 Rivet 10 Fastening part 11 Rivet hole 12, 14, 14a, 14b Maximum displacement 16
Caulking part

Claims (3)

[Claims] Claim 1: A thin plate-like structure comprising a pair of lever arms placed opposite each other, one end of which is fixed to one end of one lever arm, and the other end of which is fixed to one end of the other lever arm, connecting each lever arm in a bridge shape. a beam, and a mounting board portion that connects the pair of lever arms via a pair of hinges protruding in opposite directions from a pair of opposing side surfaces;
and a piezoelectric element that generates displacement due to piezoelectric effect, and the displacement generated by the piezoelectric element is transmitted to two lever arms, expanded by the lever principle using the hinge as a fulcrum, and transmitted to the beam, and the displacement generated by the piezoelectric element is transmitted to the beam. What is claimed is: 1. A piezoelectric element displacement magnifying mechanism of a type in which a piezoelectric element undergoes buckling motion, characterized in that an intermediate portion of the beam is fixed to the mounting substrate part. 2. The piezoelectric element displacement magnification mechanism according to claim 1, wherein the beam height of one portion of the beam fixed to the mounting substrate portion is equal to the beam height of the other portion. Displacement magnification mechanism. 3. The piezoelectric element displacement magnification mechanism according to claim 1, wherein the beam height of one portion of the beam fixed to the mounting substrate portion is different from the beam height of the other portion. Displacement magnification mechanism.