JPS59177979A - Piezoelectric actuator - Google Patents

Abstract

PURPOSE:To obtain high accuracy, large displacement and large driving force generated in addition to response property at high speed by applying voltage to a driving element for an actuator in which S-shaped bimorphs are connected alternately in series. CONSTITUTION:A guide member 3 is fixed to a holder 2, and a movable member 4 can be slid and moved vertically in the guide member 3. With an S-shaped bimorph 6, permanent polarization directions 7 are opposed before and behind the center to the longitudinal direction, two ceramic stripe pieces 12 to which thin electrodes 7 are baked are bonded on both surfaces in the thickness direction while holding a conductive support strip piece 8. With a driving element 1, only one ends are bonded while holding conductive members 11 in a plurality of the S-shaped bimorphs 6 and electrodes 7 on both surfaces of the S-shaped bimorphs 6 are conducted by a coil 9, and central electrodes are connected and conducted while bending the end sections of the support stripe pieces 8. The upper end of the driving element 1 is coupled with the movable member 4 and a lower end with the holder 2. A power supply 5 is coupled with the S-shaped bimorph 6 at the lowermost step of the driving element 1 by lead wires 10, and voltage can be applied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an actuator capable of large displacement and high-speed response movement using a piezoelectric element in an electromechanical conversion part.

[Prior art and its problems] Many mechanisms have been considered for actuators that use piezoelectric elements for electromechanical conversion. For example, a bimorph oscillator made by pasting together two piezoelectric devices with opposite polarization directions, and a drive mechanism in which the bimorph oscillators are mechanically connected in parallel to each other (Japanese Patent Application No. 70254/1989), A bolt-fastened lunge-pan type vibrator in which a plurality of polarized piezoelectric ceramics are laminated is well known. However, although these actuators have high displacement responsiveness as high-speed displacement elements, they do not satisfy the large displacement and large generation driving force required for industrial actuators.

[Objective of the Invention] The present invention improves the drawbacks of the piezoelectric actuator device having the above-mentioned conventional functions, and aims to provide an actuator that can obtain high precision, large displacement, and large generated driving force in addition to high-speed response. .

[Summary of the invention] According to the invention, this object is achieved by providing a plurality of S-shaped bimorphs consisting of piezoelectric elements, which are mechanically or adhesively connected alternately in series and connected to a central electrode. This is achieved by applying a voltage between the electrodes at both ends.

As will be explained in detail later, the 8-shaped bimorph used in the present invention is a piezoelectric ceramic having piezoelectric properties whose positive and negative curvature is different in the front and rear parts in the longitudinal direction.
The polarization and electric field direction are set so that the curvature of the letter appears.

[Effects of the Invention] This type of structure solves the problem of small displacement, which was a problem in the mechanical application of conventional piezoelectric elements. By combining responsiveness and responsiveness, a high-performance actuator can be obtained.

[Embodiments of the Invention] Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a typical embodiment of the piezoelectric actuator of the present invention, and FIGS. 2 and 3 are detailed views of the driving element 1. A guide member 3 is fixed to the frame 2, and the movable member 4 can slide vertically within the guide member 3. Second
The S-shaped bimorph 6 shown in the figure has two ceramic strips 12 with permanent polarization directions 7 opposite to each other in the longitudinal direction at the front and back of the center, and with thin electromagnetic strips 7 baked on both sides in the thickness direction. It is glued with the support strips 8 in between. Second
As shown in the figure, the drive element 1 has a plurality of S-shaped bimorphs 6 bonded to one end with the current-feeding body 11 in between, and the electrodes 7 on both sides of the S-shaped bimorphs 6 are energized by the coil 9. The central electrode is connected by bending the end of the support strip 8 and is energized.

The upper end of the drive element 1 is connected to the movable member 4, and the lower end is connected to the pedestal 2. The power source 5 is connected to the drive element 1 by a lead wire 10.
It is coupled to the S-shaped bimorph 6 at the bottom, and it is possible to apply a voltage thereto.

When voltage is applied from the power supply 5 to the piezoelectric actuator having the above structure, the drive element 1 consisting of a plurality of S-shaped bimorphs 6
The movable member 4 slides relative to the guide member 3 and operates as an actuator.

According to the structure of this embodiment, the displacement of the movable member 4 is proportional to the number of S-shaped bimorphs 6, and an arbitrary amount of displacement can be obtained depending on the number of stages of the bimorphs 6, and the generated driving force can be determined by the dimensions of the piezoelectric element. . However, as shown in FIG. 1, instead of one drive element 1, a plurality of drive elements] can also be coupled in parallel to the movable member 4 and the pedestal 2.

As a result, an actuator capable of high-speed response and high-precision positioning, which cannot be obtained with conventional actuators such as electromagnetic solenoids, can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a piezoelectric actuator showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the drive element 1 shown in FIG. FIG. 3 is an enlarged sectional view of the drive element 1 when a voltage is applied to the drive element 1. 1... Drive element, 2... Frame, 3... Guide part shrine,
4... Movable member, 5... Power source, 6... S-shaped bimorph, 7... Electrode, 8... Support strip, 9... Coil, 10... Lead wire, 11... ...Conductive member, 12
...Ceramic strip. Figure 1

Claims (1)

[Claims] In an actuator in which at least one S-shaped bimol whose electromechanical conversion part is a piezoelectric element is alternately connected in series, by applying voltage to the driving element, large displacement and high-speed response linear motion can be performed within the S-shaped plane. Featured piezoelectric actuator 0