JPH04117179A - Piezoelectric actuator - Google Patents

Abstract

PURPOSE:To operate a vibrator longitudinally and laterally and to reduce in size and weight by dividing electrodes of a vibration element into four pieces, controlling voltages to be applied to the electrodes and a phase difference, and generating a standing wave at the vibrator. CONSTITUTION:A vibrator 1, a movable section 2, and a stationary section 3, etc., are provided. In the vibrator 1, two resonators 8 of metal, divided electrodes 10a-10d divided at electrode surfaces perpendicular to the polarizing direction of a thickness mode vibration element 9 at one side of the element 9 are arranged, and an electrode 10 is arranged on the other side surface. High frequency voltages having different phase differences are applied to the electrodes 10a-10d, longitudinal vibration and two directional deflecting vibrations are generated at the vibrator 1, and four direction driving forces are generated at the vibrator 1 by four direction elliptical vibrations combined therewith. That is, four direction elliptical vibrations are generated at one vibrator 1. Thus, the vibrator 1 can be moved longitudinally and laterally in the four directions in small size and weight.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an actuator that uses a piezoelectric element to apply a driving force to a driven body.

[Conventional technology]

In recent years, with the development of piezoelectric elements, devices have been proposed that convert electrical energy into rotational or linear motion by utilizing the piezoelectric inverse effect (a phenomenon in which distortion occurs when voltage is applied). Among these, there are few piezoelectric actuators that move in a straight line,
Furthermore, there were almost no piezoelectric actuators that operated in the front, back, left, and right directions.

In addition, the electromagnetic actuator that operates in the front-rear, left-right, and left-right directions mainly uses two actuators, and performs separate operations in the front-rear direction and left-right direction, respectively.

[Invention or problem to be solved]

The present invention provides a small and lightweight piezoelectric actuator that allows a vibrating body to move in four directions: front, rear, left, and right by generating elliptical vibration in four directions in one vibrating body.

[Means to solve the problem]

In order to solve the above problems, in the present invention, the electrodes of the vibrating element are divided into four parts, and high frequency voltages with different phase differences are applied to each electrode to generate longitudinal vibration and flexural vibration in two directions in the vibrating body. , these combined elliptical vibrations in four directions generate driving forces in four directions in the vibrating body.

〔Example〕

The piezoelectric actuator of the present invention will be explained based on examples. 1, 2, and 3 show embodiments of the present invention, in which FIG. 1 is a perspective view of a piezoelectric actuator, and FIG.
The figure is a sectional view of the piezoelectric actuator, and FIG. 3 is an exploded perspective view showing the structure of the vibrating body of the piezoelectric actuator. In the figure, the piezoelectric actuator is a vibrating body 1. Movable part 2. The fixed part 3° consists of shafts 4a, 4b and bearings 5a, 5b. This vibrating body 1 includes two resonators 8 made of metal such as steel, stainless steel, or aluminum alloy, and one thickness mode vibrating element 9 made of lead zirconate titanate CPd(Zr, Ti)0□1 or the like. Divided electrodes 10a, 10 are divided into four electrode planes in a direction perpendicular to the polarization direction of the vibrating element 9.
b, 10c, and 10d, and an electrode IO is arranged on the other side, two divided electrodes are stacked facing each other to form an electrode plate II and a divided electrode plate for applying voltage to the vibrating element 9. It has a prismatic structure in which 11a, Ilb, IIc, and 11d are sandwiched between a resonator 8 and a vibrating element 9 and integrally connected by a port 12.

The driving surface 13 of the vibrating body 1 is perpendicular to the axial direction of the vibrating body l,
Further, it is located on the bottom surface parallel to the vibrating element 9, and is coated with, for example, an anti-friction material (not shown) in order to sufficiently transmit the driving force and prevent wear of the driving surface 13 and the contact surface 16.

The driving surface 13 and the contact surface 16 of the fixed part 3 are pressed into contact with each other by pressing the upper surface of the vibrating body 1 downward by the movable part 2 through a buffer 15 such as soft rubber.

Further, the support system 7 is for fixing the support plate 6 to the movable part 2. The support plate 6 has a plate structure that supports the vibrating body 1 at the minimum vibration displacement position of the vibrating body I (the center of the vibrating body). Moreover, the movable part 2 is fitted into the shafts 4a and 4b via the bearing 5a, and when the movable part 2 is operated, the movable part 2 is guided along the shaft 4a or 4b along with the other shaft by the bearing 5b and fixed. Move on section 3.

The operation of this piezoelectric actuator will be explained based on FIGS. 4 and 5.

Now, the divided electrode 10a of the vibration element 9 1Obtoe,
Between 10d and electrode 10, power supply +4a, 14b, 14c,
14d, electrode plate ti and divided electrode plates 11a, Il
b, llc, and I'd, sinωt, c, which is combined by the operating direction as shown in the diagram of FIG.
When a high frequency voltage of osωt is applied, when moving forward or backward, as shown by the dotted line in Fig. 4(a), a thickness vibration is generated in which the front and back are shifted by 90 degrees from the position where the front and back are divided.
It is as if thickness vibration and widthwise deflection vibration (back and forth direction) occur at the same time. Also, when moving to the right or left, as shown by the dotted line in Figure 4 (bl), a thickness vibration is generated in which the left and right sides are shifted by 90 degrees from the position where the left and right sides are divided, as if thickness vibration and widthwise deflection vibration ( (left and right) will now occur at the same time.

When this vibration is generated with the same high frequency voltage as the mechanical resonance frequency of the vibrating body 1, longitudinal vibration and flexural vibration are generated simultaneously, as shown by the dotted line in FIG.

The arrow in the figure is a vector representation of the vibration direction δ at a moment of vibration of the vibrating body 1.

Due to this vibration, the driving surface 13 of the vibrating body 1 is subjected to elliptical vibration 1 in the longitudinal and horizontal movement directions, which is a combination of longitudinal vibration and flexural vibration.
7 occurs as shown in FIG.

The driving surface 1
3 kicks the contact surface 16 to generate a driving force in the vibrating body l. This driving force is transmitted from the vibrating body I to the movable part 2, and the movable part 2 becomes a piezoelectric actuator that operates on the fixed part 3 while being guided by the bearing 5b along with the other shaft along the shaft 4a or 4b.

The rotation direction of the elliptical vibration 17 of the driving surface 13 is determined by the power source 14a,
It changes depending on the phase difference between the voltages applied to +4b, 14c, and +4d, and the operating direction of the piezoelectric actuator also changes accordingly.

Note that in this embodiment, the number of vibration elements 9 is two, but
A plurality of sheets may be combined as necessary.

In addition, by controlling the voltages applied to the power supplies 14a, 14b, 14c, +4d and their phase differences, the vibrating body 1
The direction of movement is not limited to front, back, left, and right, but also allows for diagonal movement.

〔Effect of the invention〕

As detailed above, according to the present invention, in an actuator that uses a vibrating element to apply a driving force to a driven body, the electrode of the vibrating element is divided into four parts, and a predetermined high-frequency voltage is supplied to each electrode. Since the elliptical vibration in two directions that generates the driving force can be obtained using only the thickness mode vibration element, it is possible to realize a small, lightweight piezoelectric actuator that has a simple structure and operates in four directions: front, back, left, and right.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an embodiment of the piezoelectric actuator of the present invention, Fig. 2 is a sectional view of an embodiment of the vibrating body of the piezoelectric actuator of the present invention, and Fig. 3 is an exploded perspective view showing the configuration of the vibrating body. , FIG. 4 is a perspective view for explaining the operation of the vibration element,
FIG. 5 is a perspective view for explaining the operation of the vibrating body, and FIG. 6 is a diagram showing the combination of the operating direction of the actuator and the phase of each power source. 1 Vibrating body 9 10a, 1ob 14a, +4b, 1 17-Elliptical vibration vibration element 10 0c, l0d 4c 14d δ Vibration direction electrode split electrode power supply

Claims (1)

[Claims] (1) In a piezoelectric actuator using a vibrating body in which a thickness mode vibrating element is sandwiched between metal or plastic and integrated, the electrodes of the vibrating element are divided into four, and the voltage applied to each electrode and the phase difference between the voltages are calculated. A piezoelectric actuator characterized in that the vibrator is controlled to generate standing wave vibrations in the vibrator, thereby causing the vibrator to move forward, backward, left and right.