JPS6151885A - Piezoelectric actuator - Google Patents

Abstract

PURPOSE:To adjust the angle of a head easily, and to strengthen a device forcibly by forming a bimorph, in which is piezoelectric element and a metallic plate are laminated, supporting one end of the bimorph by a support section and shaping a first electrode on the support section side and second and third electrodes to a nose section. CONSTITUTION:A bimorph 1 is shaped by laminating a piezoelectric element 1a and a metallic plate 1b, a first electrode 2 is formed on the support section side of the outer side surface of the piezoelectric element 1a, a second electrode 3 is shaped similarly to the nose section of the piezoelectric element 1a, a third electrode 4 is formed to the nose section in the same manner, and the electrodes 2-4 and extending sections 3a, 4a are shaped to the outer side surface of the piezoelectric element 1a. An intermediate electrode 5 is shaped onto the whole surface of the laminating surface of the piezoelectric element 1a. The arrow represents the direction of polarization of the piezoelectric element 1a. Regarding operation, the piezoelectric element 1a is extended when the same potential as the direction of polarization is applied, and it is shrunk in reverse case. Consequently, the element 1a is operated in the warping direction toward the nose section from a susceptor 6 by voltage V1, and operated in the twisting direction by voltage V2. Accordingly, the direction of deflection and the direction of wappage can be selected freely by the polarity and voltage value of voltage V1, V2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a piezoelectric actuator mainly used for head position adjustment of VTRs, audio decks, devices using magnetic discs, and the like.

Conventional configurations and their problems In recent years, devices using magnetic tapes and magnetic disks have rapidly spread, and with this, technology to control the head position so as to faithfully scan the recording track has become desirable. At the same time, piezoelectric actuators, which use piezoelectric elements to generate minute displacements, were introduced.

However, conventional piezoelectric actuators simply attach a head to the tip of a bimorph made of two piezoelectric elements and move the head up and down, making it difficult to adjust the angle between the recording track and the head. . Furthermore, since it was made by bonding two piezoelectric elements together, it had the disadvantage of being easily broken.

OBJECTS OF THE INVENTION In view of the above points, an object of the present invention is to provide a piezoelectric actuator that facilitates head angle adjustment and is strong in strength.

Structure of the Invention In order to achieve this object, the piezoelectric actuator of the present invention has a bimorph in which a piezoelectric element and a metal plate are bonded together, one end of this bimorph is supported by a support part, and a first In addition to the electrode, second and third electrodes are provided, and the second
．． By reversing the polarity of the third electrode or reversing the polarity of the applied voltage, and further extending the extended portion of the second and third electrode portions toward the support portion, the second.
The bending direction of the third electrode part is reversed, the tip part is twisted, and the angle of the head is changed. Also, the above 2. The third electrode is extended to facilitate wiring.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, 1 is a bimorph made by pasting together a piezoelectric element 1a and a metal plate 1b, 2 is a first electrode provided on the support side of the outer surface of this piezoelectric element 1λ, and 3 is also provided at the tip of the piezoelectric element 1a. The second electrode 4 is also a third electrode provided at the tip, and 3a and 4a are the second electrodes, respectively. This is an extension of the third electrode toward the support section. Also, the electrodes 2 to 4 and the extension portion 3a.

4a is formed on the outer surface of the piezoelectric element 1a.

Reference numeral 5 denotes an intermediate electrode formed on the entire bonded surface of the piezoelectric element 1a. 6 is the support stand, the curved end of bimorph 1,
Group 1 of the first electrode 2. : The part is fixed.

Is the arrow pressure? [The polarization direction of i-element 1a is shown. 7 is the second tip of bimorph 1. A pedestal is fixed between the third electrode parts 3 and 4, and 8 is a head fixed on the pedestal 7. In operation, when the same potential as the polarization direction is applied, the piezoelectric element 1'IL expands, and vice versa, it contracts. As a result, the first
The voltage v1 shown in the figure causes the tip to warp from the support base 6 toward the tip, and the voltage v2 causes the tip to twist. Therefore, the direction of deflection can be freely selected depending on the polarity and voltage value of the voltages V, , V2.

As described above, the actuator of the present invention has a voltage of "1+v2".
Depending on the polarity and voltage value, the amount of deflection and twist angle of the tip can be freely selected, allowing the head position to be optimally aligned with the recording track.

Further, since the extension portion of the electric connection is concentrated on the support portion side, wiring processing is easy. Furthermore, since the piezoelectric element and the metal plate are bonded together, it has the advantage of being strong.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main parts of an embodiment of the piezoelectric actuator of the present invention, and FIG. 2 is a perspective view showing the piezoelectric actuator with a head and a base attached. 1... Bimorph, 1a... Piezoelectric element, 1
b... Metal plate, 2... First electrode, 3...
...Second electrode, 4...Third electrode, 3a,
4a...Extension part, 6...Intermediate electrode, 6.
...Support stand, 7...Base part, 8...
head. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
figure

Claims (1)

[Claims] It has a bimorph in which a piezoelectric element and a metal plate are bonded together, one end of this bimorph is supported by a support part, a first electrode is provided on the support part side, second and third electrode parts are provided at the tip part, and the piezoelectric A single intermediate electrode is provided on the bonding surface of the element and the metal plate, and the polarity of the second and third electrode portions is reversed or the polarity of the applied voltage is reversed, and the second and third electrodes are A piezoelectric actuator in which an extension part of the part is extended toward the support part side.