JPH0479155B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a piezoelectric displacement device suitable for a microscopic step-like linear fine movement device used to minutely adjust the position of an object.

Conventional technology In the field of precision instruments, minute movement devices are required. A structure in which a minute displacement body made of a large number of laminated piezoelectric bodies is used as both a step displacement mechanism and a clamp mechanism has been proposed and used. Although these are suitable for the slight movement of relatively heavy objects, they have a complex structure and are expensive, so it seems that they are still a step away from becoming widespread.

Means for Solving the Problems The present invention consists of two horizontal beams that extend and contract in the length direction, and three vertical beams that connect each other between the intermediate portions of these two horizontal beams. To provide an integrated piezoelectric displacement device which has a function of expanding displacement in the vertical direction by expanding and contracting, and also has a function of displacing in the horizontal direction, and is particularly suitable for a step-like linear fine movement device.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1st
2, 10 is a piezoelectric displacement device of the present invention made of a piezoelectric material such as lead zirconate titanate or barium titanate, or a composite piezoelectric material made of powder of these materials and epoxy resin, and 1a, 1b
are two horizontal beams extending and contracting in the length direction, 2a,
2b and 2c are three vertical beams connected to the horizontal beams 1a and 1b, and among the three vertical beams, electrodes 3 are provided on both sides of the vertical beams 2a and 2b, respectively.
a, 3b (hereinafter, the vertical beams 2a, 2b with electrodes attached are called the vertical operating beam, and the beam 2c without the electrodes is called the vertical fixed beam), and also on both sides of the horizontal beams 1a, 1b. Silver,
Electrodes 4a, 4b made of platinum or the like are attached, and each of these beams is constructed as a continuous piece. 5 is a power source for driving the vertically operating beam 2b; 6 is an electrode 3b attached to both sides of the vertically operating beam 2b;
Lead wire 7 applies voltage to horizontal beam 1
8 is a lead wire for applying a voltage to electrodes 4a and 4b attached to both sides of horizontal beams 1a and 1b. Further, although not shown, the structure is such that a voltage is applied to the electrode 3a of the vertically operating beam 2a in the same way as the vertically operating beam 2b.

The horizontal beams 1a, 1b, the vertical operating beam 2
a and 2b are as shown by arrows Px and Py in Fig. 2,
The beams are polarized in the thickness direction, and when a voltage is applied between the electrodes, each beam expands and contracts in the direction perpendicular to the polarization direction (the length direction of each beam) due to the piezoelectric transverse effect, depending on the polarity of the voltage. (The magnitude of the displacement is determined by the piezoelectric constant d31, the electric field E, and the beam length l
). For example, when voltages with the polarities shown in FIG. 2 are applied in the polarization directions Px and Py, the horizontal beams 1a and 1b will move as shown by the arrow αx in FIG.
Contraction occurs in the length direction and horizontal displacement is obtained.
Further, the vertically operating beams 2a and 2b contract in the length direction as shown by the arrow αy, and a displacement in the vertical direction is obtained.

In the present invention, as shown in FIG. 3, when the horizontal beam 1b is fixed, when the distances from the vertical fixed beam 2c to the movable ends of the vertical operating beam 2b and the horizontal beam 1a are a and b, respectively, the vertical direction The displacement amount Δy1 is expanded to approximately b/a·Δy1 at the movable end of the horizontal beam 1a. That is,
By changing the combination of the polarization direction and the polarity of the applied voltage, the horizontal beams 1a, 1b and the vertical beams 2a, 2b can be expanded or contracted, resulting in an expanded two-dimensional displacement at the tip of the horizontal beam. is obtained. In the embodiment shown in FIG. 1, the left and right movable ends of the horizontal beam can be controlled in displacement symmetrically with respect to the vertical fixed beam 2c, since they are integrated in a symmetrical shape with the vertical fixed beam 2c as the center. , it is also possible to obtain an asymmetric enlarged displacement in the vertical direction by driving the vertical beams 2a, 2b independently. Of course, if the electrodes 4a and 4b are separated into left and right parts at the center of the horizontal beams 1a and 1b, and each is driven by an independent power source, asymmetrical displacement in the horizontal direction can also be obtained.

FIG. 4 shows a piezoelectric displacement device in which the vertical fixed beam 2c in FIG. 1 is also made into a vertically movable beam that is displaced in the vertical direction, and the dimensions of these vertically movable beams are lengthened to increase the displacement in the vertical direction. 3c is an electrode made of silver, platinum, etc. attached to both sides of the vertically moving beam 2c. In this case, the three vertical beams 2a, 2b, 2c extend to the horizontal beam, increasing their dimensions. Then, when the vertical working beams 2a and 2b are contracted in the vertical direction as shown by the arrow αy, and the vertical working beam 2c is conversely expanded as shown by the arrow βy, at the movable end of the horizontal beams 1a and 1b, the vertical working beam 2a or The amount of contraction due to the vertical movement beam 2b and the amount of expansion due to the vertical motion beam 2c are added together and expanded to obtain a larger amount of displacement. This embodiment is suitable for applications where displacement is symmetrical.

Note that the electrodes of the horizontal beams 1a and 1b are 4a1,
It is divided into 4a2, 4b1, and 4b2, and the horizontal displacement can be arbitrarily controlled by applying a voltage in common or independently to each of them.

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 raw materials.
This is integrally punched into the shape described in each example 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 DC high voltage is applied between each electrode to polarize the electrodes to obtain an integrated piezoelectric displacement device. Furthermore, piezoelectric powder such as lead zirconate titanate and epoxy resin or PVDF
In the case of a composite piezoelectric material made of a mixture with various organic substances such as, the piezoelectric material displacement device of the present invention can be obtained by performing processes such as polarization and polarization after extrusion, punching, and molding with a die.

Figure 5 shows an example in which the device of the present invention is applied to a step-like linear fine movement device, in which a horizontal beam 1
The piezoelectric displacement device of the present invention, in which gripping claws 11a and 11b made of ceramic or synthetic resin are fixed to four movable ends of a and 1b with adhesive or the like, is inserted between a pair of rails 12a and 12b that serve as movement guides. The gripping claws 11a and 11b are set so as to sandwich the upper and lower surfaces of the rail, and the piezoelectric displacement device is configured to move along the rail.

In FIG. 5A, the piezoelectric displacement device uses a power supply Vx and a switch Sx to move the horizontal beams 1a,
By applying a voltage to the electrodes 4a and 4b attached to both sides of the beam, the horizontal beams 1a and 1b are caused to contract and return in the horizontal direction, respectively. Also, the vertical movement beams 2a, 2b
are the power supply Vy and switches S1 and S2 independently.
By applying a voltage to the electrodes 3a and 3b provided on both sides, they are driven ON and OFF, and both perform contraction and return movements in the vertical direction, but the vertical displacement is at the movable end of the horizontal beam, as described above. will be expanded to.

The operation of this device will be explained with reference to FIG. In step 1, the vertical movement beam 2b contracts in the vertical direction due to S2ON, and this displacement is expanded so that the gripping claws 11b grip and hold the rails 12a and 12b. In the second step, the horizontal beam contracts due to SxON, and the left movable end moves to the right by Δx. In the third step, the vertical movement beam 2a is contracted by S1ON, the displacement is expanded, and the gripping claw 11a is moved between the rails 12a and 12.
Grab and hold b. In the fourth step, the vertical beam 2b returns to its original position by S2OFF, and the gripping claw 11b releases the rail. In step 5, the horizontal beam is restored by SxOFF, and the right movable end moves to the right by △x. From the 2nd cycle, step 1 is S2
ON, then S1 OFF, and then steps 1 to 5.
Do the following. By repeating steps 1 to 5, it is possible to displace it in one direction, for example, as shown by the arrow X in FIG. 5A. Also, by changing the order of the steps, or by changing the horizontal beam 1
By using extension instead of contraction of a and 1b, displacement to the left can also be obtained.

Figure 7 shows another example in which the device of the present invention is applied to a step-like linear fine movement device, in which the horizontal beam 1
The claws 21a, 21b hit the four movable ends of a, 1b.
A piezoelectric displacement device 20 provided with a piezoelectric body is set in a rail 22 having a concave cross section and made of ceramic, metal, synthetic resin, or the like. In this example, the vertical movement beam is extended to increase the displacement in the direction in which the movable ends of the horizontal beams 1a and 1b respectively widen, and the claws hit the inner wall of the concave rail to fix the position. The operation of this device will be explained with reference to FIG. S2 in step 1
By turning ON, the vertical movement beam 2b extends in the vertical direction, and this displacement is magnified, causing the contact claw 21 to move towards the rail 2.
2 and fix the position. in the second step
The horizontal beam contracts due to SxON, and the left movable end moves to the right by Δx. S1 in the third step
By turning ON, the vertical operation beam 2a is extended, and the displacement at the left movable ends of the horizontal beams 1a and 1b is expanded, and the contact pawl 21a hits the inner wall of the rail 22, fixing the position. In the fourth step, the vertical movement beam 2b returns to its original position by S2OFF, and the hit claw leaves the rail. In the fifth step, the horizontal beams 1a and 1b are returned by SxOFF, and at this time, the right movable end of the horizontal beam moves to the right by Δx.

In this example as well, it is possible to move the beam to the left by changing the order of the steps or by using the horizontal beam in the extending direction.

In the above explanation, the operation was explained using extension-return or contraction-return, but even larger displacement can be obtained by using the two states of extension-retraction. This can be done by using power supplies with different polarities or by using a bias power supply. Also, whether to use expansion or contraction for each beam depends on the application and purpose, but when using the piezoelectric transverse effect, when a voltage of the same polarity as that for polarization is applied, contraction occurs. Therefore, in order to prevent performance deterioration due to de-separation, it is generally preferable to use contraction displacement as shown in FIG. In addition, horizontal beams 1a, 1b,
Electrostrictive materials can also be used in the case of the example of FIG. 5 in which both the vertically operating beams 2a and 2b use contraction displacement, or in the case of using a bias voltage. When a voltage is applied to electrostrictive materials,
In the direction perpendicular to this, a contraction displacement proportional to the square of the voltage is obtained regardless of the polarity of the voltage. Therefore, the present invention, which utilizes the strain caused by the application of voltage, includes the use of electrostrictive materials. Electrostrictive materials can be manufactured in exactly the same way as piezoelectric materials, except that polarization treatment is not required.

Effects of the Invention As described above, the present invention provides an integrated piezoelectric displacement device capable of controlling two-dimensional displacement, which has a displacement magnification function in one direction and also has a displacement function in a direction perpendicular to this direction. Since there are no adhesive parts or joints for expanding displacement, there is no instability in displacement caused by these, and problems of complexity and wobbling when adding another displacement expanding function can be solved.
Furthermore, the present invention has an extremely simple structure, can be manufactured in large quantities at low cost, and is characterized by the fact that products with the same performance can be easily obtained. Furthermore, depending on the application, a plurality of piezoelectric displacement devices of the present invention can be stacked and used for load-bearing purposes.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the piezoelectric displacement device of the present invention, FIG. 2 is a diagram showing a voltage application state of the device shown in FIG. 1, and FIG. 3 is an operation of the piezoelectric displacement device of the present invention. 4 is a perspective view showing another embodiment of the device of the present invention, and FIG. 5 is a diagram showing an example in which the piezoelectric displacement device of the present invention is applied to a step-like linear fine movement device, and A is a front view thereof. B is a sectional view taken along line A-A of A;
C is a perspective view of the piezoelectric body displacement device of the present invention used in this device. FIG. 6 is a diagram for explaining the operation of the piezoelectric body displacement device in the above-mentioned fine movement device, and FIG. 7 shows another example of the fine movement device, where A is a front view of the present invention, and B is B of FIG. FIG. 8, a sectional view taken along the line -B, is a diagram for explaining the operation of the piezoelectric body displacement device in the fine movement device. 1a, 1b...horizontal beam, 2a-2c...vertical beam, 3a-3c...electrode.

Claims (1)

[Claims] 1 Made of a piezoelectric material, two horizontal beams and two vertical beams connecting the intermediate portions of these two horizontal beams are integrally formed, and the two horizontal beams and the three horizontal beams are integrally formed. A piezoelectric displacement device characterized in that drive electrodes are provided on at least two left and right vertical beams among the vertical beams.