JPH0438152B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a piezoelectric displacement device with excellent performance used for minute displacement and minute angle control, high-speed response, and the like.

Conventional technology and problems Piezoelectric materials undergo distortion and displacement when voltage is applied. This amount of displacement is generally minute, and various efforts have been made to obtain a practical amount of displacement.

A so-called laminated displacement body made by laminating a plurality of piezoelectric plates utilizes the longitudinal effect displacement of the piezoelectric plates, and its piezoelectric constant d33 is greatly advantageous. However, since the amount of displacement is proportional to the length in the stacking direction, many piezoelectric plates must be stacked to obtain the required amount of displacement, which is a complicated process, which is why this type of device is expensive. It was one of the. Further, the displacement of the piezoelectric plates is transmitted in the stacking direction through the contact portions with the adjacent piezoelectric plates, but since the amount of displacement is minute, the overall amount of displacement is greatly influenced by the state of the contact portions. Moreover, with repeated use, the condition of the contact portion changes, resulting in unstable characteristics.

Another idea is the bimorph, which uses the transverse effect of piezoelectric plates. A bimorph is, for example, a metal plate with piezoelectric sheets pasted on both sides.
By applying an appropriate voltage to the two piezoelectric bodies, when one piezoelectric body expands, the other piezoelectric body contracts, causing the metal plate to bend in one direction. The piezoelectric constant d31 of the transverse effect is smaller than d33, which is disadvantageous, but the bimorph has the advantage of being able to obtain a large displacement proportional to the square of the length dimension. However, stress is applied to the bimorph due to the adhesion and bonding of two piezoelectric plates, and in order to obtain displacement due to bending, stress is also added when mechanically fixing the ends of the bimorph. changes both thermally and over time, exhibiting complex behavior in terms of minute displacements. These changes change the angle in the bending direction, which is magnified as a tip displacement proportional to the length dimension, resulting in an error, which has the disadvantage of becoming unstable thermally and over time.

Means for Solving the Problems The present invention provides a horizontal beam, a total of four vertical beams, two each connected to both ends of the horizontal beam,
A horizontal beam connected to the other end of each of the vertical beams and divided at the center, at least one horizontal beam on each of the left and right sides.
It is characterized by the fact that the vertical beam of the book is provided with a driving electrode that expands and contracts the vertical beam in the vertical direction, allowing a large displacement to be obtained without the need for a special expansion mechanism, and also allowing for angle control. The present invention provides a piezoelectric body displacement device.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the piezoelectric displacement device of the present invention, which is integrally formed of lead zirconate titanate, barium titanate, or the like.

1 is a horizontal beam, 2a to 2d are vertical beams formed in parallel at both ends of the horizontal beam 1, two of which are vertical beams 2a at both ends,
Driving electrodes 3a and 3b made of silver, platinum, etc. are provided on both sides of electrode 2b, respectively. The vertical beams 2a and 2b (hereinafter referred to as vertical operation beams) provided with the electrodes are as shown in FIG.
It is polarized in the direction of arrow P. 4a and 4b are horizontal beams connected to the other ends of the four vertical beams, and are separated into right and left by a slit 5 in the center. 6 is a lead wire for applying voltage to the electrode, and 7 is a power source.

In the above device, the vertical working beams 2a, 2b
is polarized in its thickness direction (perpendicular to the length direction of the vertical beam), so when a voltage is applied in the polarization direction, the vertically operating beam expands and contracts in the length direction depending on the polarity. For example, when applying a voltage in the direction shown in Figure 2, as shown by arrow α,
The vertical working beams 2a, 2b contract in the length direction. And this contraction displacement is the vertical beam 2c, 2d
(Hereinafter, this will be referred to as a vertical fixed beam) is used as a support and the horizontal beams 4a and 4b are expanded at the central slit portions. That is, as shown in FIG.
2d and the central slit portion 5 of the horizontal beams 4a and 4b.
When the lengths up to the horizontal beams are a and b, respectively, the contraction displacement △y1 is expanded by approximately b/a times in the direction opposite to the contraction direction (arrow Y direction) at the central slit portion of the horizontal beams 4a and 4b. . Moreover, when applying a voltage opposite to that in FIG.
undergoes an elongated displacement, and an enlarged displacement in the direction opposite to the elongated direction is obtained at the central slit portion.

FIG. 4 (same reference numerals as FIG. 1) shows another embodiment of the present invention, in which electrodes 3c and 3d are also provided on both sides of the vertical fixed beams 2c and 2d, respectively, in the embodiment of FIG. 2a and 2c in this example.
and 2b and 2d are one (e.g. vertical beam 2
When the beams a and 2b) contract as shown by the arrow α, the displacement of the other vertical beam (vertical beams 2c and 2d) is added by applying a voltage in the direction of expansion as shown by the arrow β. Expanded. Furthermore, in this embodiment, electrodes 8a and 8b are attached to both surfaces of the horizontal beams 4a and 4b, respectively, and polarized, so that they can be displaced in the horizontal direction using a separate power source. . Therefore, when a voltage is applied in a direction that horizontally extends the horizontal beam 4a and contracts the horizontal beam 4b, the position of the slit 5 moves in the direction of the arrow x1. Similarly, it can also be moved in the x2 direction by applying a voltage in the opposite direction.

A piezoelectric body displacement device having such a displacement magnification mechanism can be manufactured, for example, by the following conventional method.

That is, a green sheet is obtained by a conventional method using lead zirconate titanate or barium titanate as a raw material. This is integrally punched into the shape described in the examples and fired at a high temperature to obtain a sintered body. Then, electrodes are attached to necessary portions by screen printing or vapor deposition depending on each embodiment. Next, a high DC voltage is applied between each electrode to complete polarization. Incidentally, after obtaining a continuous sintered body without slits 5, the slits 5 may be formed using a cutter at an appropriate time. Furthermore,
A circular notch is provided at the connection portion between each vertical beam and the horizontal beams 4a, 4b where rotation occurs in conjunction with the displacement amplification mechanism, thereby reducing stress and facilitating displacement expansion. It is also possible to take measures such as preventing the connecting portion from being damaged.

In the present invention, a general piezoelectric body made of a piezoelectric material such as lead zirconate titanate has been described, but an electrostrictive material may also be used when a vertical beam is contracted or when a bias voltage is used. The invention can be practiced. When a voltage is applied to an electrostrictive material, a contraction displacement in a direction perpendicular to the voltage is proportional to the square of the voltage, regardless of the polarity of the voltage. In the present invention, which utilizes strain caused by the application of voltage, electrostrictive materials are also included within the technical scope of the present invention. Devices using electrostrictive materials can be fabricated in the same manner as piezoelectric materials, except that polarization is not required. Furthermore, composite piezoelectric bodies made of a piezoelectric powder such as lead zirconate titanate and an organic substance such as an epoxy resin can also be integrated into the present invention by forming, polarizing, and polarizing processes using appropriate methods. It is possible to obtain a piezoelectric body displacement device that is

Effects of the Invention The present invention has the above configuration,
It has many advantages such as:

Since the central slit 5 is provided in the upper horizontal beam constituting the operating part, not only can the vertical displacement of the vertical beam be easily expanded, but also the amount of displacement of the vertical beam can be independently controlled. , 4b can be changed in magnitude and direction, and can also be used for applications such as changing the angle of an object placed in the central slit portion 5.

Since the left and right parts are formed symmetrically, the structure is more stable, easier to use, and more rigid than when the left part or the right part is used alone.

There are no adhesive or joint parts for increasing displacement, and the problems of complexity and wobbling when adding another displacement expanding mechanism can be solved.

Since the displacement due to direct expansion and contraction is used instead of the expansion of displacement due to bending, the error in displacement due to stress on the attachment part is not magnified, and stable displacement can be obtained.

The present invention has an extremely simple structure, can be manufactured in large quantities at low cost, and products with the same performance can be easily obtained.

It is also possible to stack a plurality of the devices of the present invention in the thickness direction and use them for load-bearing purposes.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the piezoelectric displacement device of the present invention, FIG. 2 is a cross-sectional view for explaining the operation of the device of the present invention, and FIG. 3 is the principle of operation of the enlarging mechanism in the device of the present invention. FIG. 4 is a front view showing another embodiment of the device of the present invention. 1... Horizontal beam, 2a to 2d... Vertical beam, 3a to 3d... Electrode, 4a, 4b... Divided horizontal beam.

Claims (1)

[Claims] 1 A horizontal beam, a total of four vertical beams, two each connected to each end of the horizontal beam, and a horizontal beam connected to the other end of each of the vertical beams and divided at the center, at least on the left and right sides. 1. An integrally formed piezoelectric displacement device, characterized in that one vertical beam is provided with a driving electrode for vertically expanding and contracting the vertical beam.