JPS60148390A - Drive piezoelectric device - Google Patents

Abstract

PURPOSE:To increase the moving speed with a simple configuration by forming a rectilinearly moving piezoelectric element by superposing two piezoelectric elements. CONSTITUTION:A piezoelectric device 10 has a thin platelike bimorph 12a of rectangular shape, and the first and second piezoelectric units 12b, 12c respectively secured to the both longitudinal ends of the bimorph. The bimorph 12a has the first electrode plate 11, a pair of piezoelectric units 13, 14 secured to the both surfaces of the plate 11, and the second electrode plates 15, 16 secured to the opposite sides to one surfaces of the units 13, 14 facing the first plate 11. The elements 12b, 12c have piezoelectric units 17, 20, and electrode plates 17, 18, 21, 22 respectively secured to the both ends of the units 17, 20 in the elongating directions. The bimorph 12a and the elements 12b, 12c are connected in parallel with a controller.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field - The present invention relates to a driving piezoelectric device suitably used in, for example, a fine adjustment device for tools of NC machine tools.

BACKGROUND TECHNOLOGY Conventionally, drive piezoelectric devices forming linear motors are
As shown in FIG. 1, there is a first piezoelectric element section 2, and second piezoelectric element sections 3 formed at both longitudinal ends of the first piezoelectric element section 2. It is composed of a third piezoelectric element section 4. The operating process of this piezoelectric device 1 is to first insert the piezoelectric device 1 into the groove block 5, extend the second piezoelectric element 3, and press it against the inner wall 6' of the groove block 5 as shown in FIG. 1(1). and identify it. Next, after shrinking the third piezoelectric element part 4, when the first piezoelectric element part 2 is expanded, the third piezoelectric element part 4 will be extended by a distance equal to the extension of the first piezoelectric element part 2, as shown in FIG. 1(2). 1iiiI Move by L. Next, the first piezoelectric element part 2 is expanded and fixed to the inner wall 6, and the second
After reducing the piezoelectric element part 3, 'A' causes the piezoelectric element part 2 to be reduced. As a result, the piezoelectric device 1 has been moved by a distance to the right in FIG. 1, as shown in FIG. 1(3). By repeating the operations from F11 in FIG. 1 to (4) in FIG. 1, the piezoelectric device 1 is cut into the inner wall 6 of the groove block 5 and moved in one direction.

In such a piezoelectric device 1, piezoelectric element portions 2, 3 . .

The movement of the piezoelectric element 1 may be slow due to the extremely small extension length of the groove block 5. However, the movement of the piezoelectric device 1 may be slow due to the accuracy of the width of the groove block 5. )
OBJECT OF THE INVENTION The present invention solves the above-mentioned technical problems and provides a driving piezoelectric device which has a simple structure and has an increased moving speed.

Embodiment FIG. 2 is a perspective view of the IE electrical device 10 according to the present invention. The piezoelectric device 10 basically includes a rectangular flat-plate bimorph 12a, and a U'l piezoelectric element 12b and a second piezoelectric element 12c fixed to both longitudinal ends of the bimorph 12a, respectively.
including. The bimorph 12a includes a gt electrode plate 11 and a pair of piezoelectric bodies 1. fixed to both surfaces of the gt electrode plate 11. , 14 and second electrode plates 15 and 16 respectively fixed to the sides opposite to the one side facing the first electrode plate 11 of the piezoelectric body 13 and 14. In this way, the first electrode plate 11 and Second electrode plate 15.16
The piezoelectric bodies 13, 14 are constructed in a sandwich-like manner. A piezoelectric element 12b is fixed to one longitudinal end (left side in FIG. 2) of the bimorph 12a.

Pressure! The element 12b includes a piezoelectric body 17 connected to one end of the bimorph 1.2a, and a first electrode plate 18 fixed to both ends of the piezoelectric body 17 in the extending direction. and a second electrode plate 19. The elongation direction of the piezoelectric body 17 is perpendicular to the longitudinal direction of the bimorph 12a, and the thickness L of the piezoelectric body 17 in the elongation direction is
is selected to be larger than the thickness Ll of the bimorph 12a. The second piezoelectric element 12c fixed to the other end of the bimorph 12a in the longitudinal direction (right side in FIG. 2) is similar to the first piezoelectric element 1.
2b, and a piezoelectric body 20, and first electrode plates 21, which are respectively fixed to both ends of the piezoelectric body 20 in the extending direction. It consists of a second electrode plate 22.

As the material of the piezoelectric body 12, for example, a composite of an inorganic material and a polymer material is used. Composites include piezoelectric porcelain powders, such as barium titanate.

Lead zirconate titanate (PZT) etc. in an equal amount of 1H1
Preferred are polymeric materials containing vinylidene fluoride, such as vinylidene fluoride homopolymers and vinylidene fluoride-3.
Vinyl-17dene fluoride copolymers such as fluorinated tyrene copolymers are preferred.

The bimorph 12a and the pair of piezoelectric elements 12b and 12c of the piezoelectric device 10 are each connected in parallel to a control circuit (not shown). This results in bimorph 12a
Thus, independent connection states between the first piezoelectric element 12b and the second piezoelectric element 12c are achieved.

FIG. 3 is a plan view of one embodiment of the present invention, and FIG. 4 is a side view thereof. The piezoelectric device IO has a straight path 22 surrounded by an inner wall 21 of a groove block 50 extending in the left-right direction in FIG.
inserted into. Assume that a driving pulse shown in FIG. 5 is applied to the piezoelectric device 1O, which is allowed to move in only one direction as described above. First piezoelectric element 12bi of piezoelectric device 10
To this, a voltage having the waveform shown in FIG. 5(1) is applied, and to the bimorph 12a, a voltage having the waveform shown in FIG. 5(2) is applied,
A voltage with the waveform shown in Fig. 5 (3) is applied to the second piezoelectric element 12c to cause -C to move straight in one direction, and in the case of reverse movement, the waveforms of ill e t2) p t3) are reversed. do. Each piezoelectric cord part 1 forming a so-called bimorph
2 a'.

As shown in FIG. 1O, piezoelectric bodies 13 and 14 degrees having different electrical polarities are used for the piezoelectric bodies 12b and 12c, and therefore can be bent in the direction of arrow R by application of a predetermined voltage. In FIG. 6 il+, all piezoelectric devices 1υ are in a state of no voltage I>1, and from time T I to T2, a predetermined voltage is applied only to the first piezoelectric element 12b as shown in FIG. 6 (2). As a result, the first piezoelectric element 12b is fixed to the inner wall 21 of the straight path 22 in the groove block 50. Between time 'r2 and T4, as shown in FIG. 6(3), the bimorph 12. A is also applied with TIC pressure and becomes curved, so that the bimorph 12a is in a contracted state within the straight path 22. As a result, the second piezoelectric element 12c, which is shrinking due to the application of a reverse voltage, moves toward the first piezoelectric element 12b by an amount corresponding to the shrinkage of the bimorph 12a. Between time T4 and T5, the second piezoelectric element 1
2c is also applied with voltage, which causes the piezoelectric device +410
is fixed at ``&21'' in block 50 (111).

Between time T5 and T6, the first
A reverse voltage is applied to the piezoelectric element 12b to reduce the 1>1 piezoelectric element 12b, and the voltage application to the bimorph 12a is canceled between time r6 and T7 as shown in FIG. 6(6). In this way, by applying a voltage to only the second piezoelectric element 12c and fixing it to the inner wall 21, the piezoelectric device 10 is moved toward the left in FIG. 6 by the amount of contraction of the bimorph 12a. Between time T7 and T8, the 6th
As shown in FIG. 7, voltage is applied again to the first piezoelectric element 12b and the first piezoelectric element 12c, and by repeating the above operation, the piezoelectric device 10 moves in one direction within the straight passage 22 of the groove block 5(). I can do it. Such a piezoelectric device 1
At one end on the opposite side to the direction of movement of the piezoelectric device 10, there is a rod (
(not shown) is attached, thereby allowing the piezoelectric device 10 to function as a linear motor.

A straight path 22 formed in the groove block 5 ( ) shown in the fourth figure
is the width of the first piezoelectric element 12b and the second piezoelectric element 12b of the piezoelectric device IO.
The bimorph 12 is larger than the thickness of the piezoelectric element 12c.
The height 1 of the straight path 22 is selected to be such that even when curved due to voltage application, it does not contact the inner wall 21 of the groove block 50, and the height 1 of the straight path 22 is
The thickness is selected to be larger than the thickness of the pressure 1 section element 1'2c.

Therefore, the first piezoelectric element 12b and the second piezoelectric element 12
The movement state of the piezoelectric device 10 can be changed by elongating c by applying and releasing a predetermined voltage, and by decreasing <rg! jl, stop, and fluency can be achieved.

According to the experimental results of the present inventors, the curvature of the bimorph 12a due to voltage application can be arbitrarily selected depending on the size of the Ichikawa, and the curvature of the bimorph 12a can be set to a large value. With the operation of the cycle, we were able to make a very large shift 1111. This also increased the pressure and the load.
Since the width of the displacement meter per cycle can be increased, practicality is improved.

In the actual embodiment, the cp extension direction of the first piezoelectric element 12b and the second piezoelectric element 12 and the curving direction of the bimorph 12a are defined as the same direction, but as shown in FIG. The piezoelectric element 12b and the second piezoelectric element 12100.101 are connected to the electrical insulator 1
-C may also be configured to be shut off by 02.

The piezoelectric device according to the present invention is a tool for NC machining).

Positioning of workpieces, etc., moving microscope specimens, optical system reflection field (I!J reflection, imaginary fine angle adjustment, etc.) However, it can be widely applied in other technical fields as well.

Effects As described above, according to the present invention, since the linear pressure chain element is formed by stacking two pressure '[L elements], it is possible to increase the moving speed of the driving electrical equipment fl.

[Brief explanation of drawings]

Fig. 1 is a drive explanatory diagram of a prior art piezoelectric device, and Fig. 2 is a perspective view of a piezoelectric device io according to the present invention.
Fig. 3 is a plan view of an embodiment of the present invention, Fig. 414 is a side view thereof, and Fig. 45 is a bimorph 12a, i-th pressure! Element 1
2b is a voltage waveform diagram applied to the second piezoelectric element 12c, FIG. 0 is an enlarged sectional view of a bimorph, and FIG. 11 is a sectional view showing an embodiment of a song according to the present invention. 1.10...Piezoelectric device 4.11, 18.21...First electronic plate, 12a...Bimorph, 12b...First
Piezoelectric element, l 2 c =・Second piezoelectric element, 13, 14
,17゜20...piezoelectric body, 15,16,19.22・
...Second Electrode Agent Patent Attorney Kei Nishi Part 1 Figure 1 Figure 2 Figure 3 Figure 414 Figure 5 (7) Lotto ==== Ancho Figure 7 Figure 9

Claims (1)

[Claims] A pair of rectilinear piezoelectric elements, including a rectangular piezoelectric body made of a piezoelectric material and an electrode plate fixed to one surface of the piezoelectric body, the piezoelectric bodies being attached back to back. The element, two expansion/contraction piezoelectric elements including a cubic piezoelectric body disposed at both longitudinal ends of the linear piezoelectric element, and electrode plates fixed to both end surfaces of the piezoelectric body are connected by voltage application. A driving device characterized in that the rectilinear piezoelectric element, which is curved convexly or concavely in a direction perpendicular to the plane of the piezoelectric element, is assembled in an H shape such that the direction of curvature of the piezoelectric element for linear movement is orthogonal to the direction of expansion and contraction of the piezoelectric element for expansion and contraction. Piezoelectric device.