JPH0314955Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a drive piezoelectric device that is suitably used, for example, in a fine adjustment device for tools of NC machine tools.

BACKGROUND ART FIG. 1 is an operational diagram of a prior art piezoelectric device for driving a linear motor. The movable body 1 includes a first piezoelectric element part 2 extending in the moving direction, and a second piezoelectric element part 3 and a third piezoelectric element part 4 formed at both longitudinal ends of the first piezoelectric element. In the operation process of the movable body 1, first, as shown in FIG. 1, the movable body 1 is inserted into a guide body 5 such as a groove block. Next, as shown in FIG. 1 and 2, the second piezoelectric element portion 3 is extended in a direction perpendicular to the moving direction and is pressed against and fixed to the inner wall surface 6 of the guide body 5. Next, the first piezoelectric element section 2 is extended by a predetermined length L in parallel to the moving direction. At this time, the third piezoelectric element portion 4
is displaced by a length L in the direction of movement. Next, the first
As shown in FIG. 3, the third piezoelectric element portion 4 is extended in a direction perpendicular to the moving direction and is pressed against and fixed to the inner wall surface 6 of the guide body 5. Next, after the second piezoelectric element section 3 is reduced in a direction perpendicular to the moving direction, the first piezoelectric element section 2 is reduced in parallel to the moving direction. At this time, the moving body 1 has moved by a distance L to the right in FIG.
In FIG. 1, the second piezoelectric element portion is first extended perpendicular to the direction of movement and is pressed against the inner wall surface 6 of the guide body 5 and fixed therein. Next, after reducing the third piezoelectric element section perpendicularly to the moving direction, the first piezoelectric element section 2 is expanded parallel to the moving direction. By repeating the operations from FIG. 1 to FIG. 1 in this way, the movable body 1 can be moved in one direction along the inner wall surface 6 of the guide body 5.

In such a movable body 1 of the prior art, the displacement amount of expansion and contraction of the piezoelectric element portions 2, 3, and 4 is extremely small, so the moving speed of the movable body 1 is slow, and moreover, the width of the inner wall surface 6 of the guide body 5, etc. Extremely high precision was required.

Purpose The purpose of this invention is to solve the above technical problems,
It is an object of the present invention to provide a driving piezoelectric device that has a simple configuration, can increase moving speed, and operates stably.

The present invention includes (a) a longitudinal passageway 23 formed by a pair of mutually opposing parallel inner wall surfaces 22;
A guide body 2 in which an escape recess 24 having a predetermined width H and extending in the longitudinal direction is formed in an inner wall surface 22.
1, (b) a movable body 7 housed in the passage 23, (b1) a first piezoelectric element part 8, (b11) having a width D1 smaller than the width H; Extending in the longitudinal direction of the inner wall surface 2
(b12) a pair of connecting portions 12a, 13 each formed on both sides of the surface of the first piezoelectric body 11 in the width direction so as to extend parallel to the longitudinal direction;
a, and a pair of first comb-shaped electrodes 12, 13 configured by a plurality of leg portions 12b, 13b extending vertically from each connecting portion 12a, 13a so as to alternately face each other and intersect with each other. (b2) a passage 23 with respect to the first piezoelectric element part 8;
Around a first axis 65 parallel to the inner wall surface 22 and perpendicular to the longitudinal direction on one side in the longitudinal direction,
A second piezoelectric element part 9 is provided so as to be angularly displaceable with respect to the first piezoelectric element part 8, and (b21) has a width D2 larger than the width H and is a plate-shaped member parallel to the inner wall surface 22. a second piezoelectric body 14; (b22) a pair of connecting portions 1 formed on both sides of the surface of the second piezoelectric body 14 in the width direction;
5a, 16a and each connecting portion 15a, 16a
A pair of second comb-shaped electrodes 15, 1 constituted by a plurality of vertically extending leg portions 15b, 16b that alternately face each other and intersect with each other.
(b3) a passage 23 with respect to the first piezoelectric element part 8;
Around the second axis 66 parallel to the inner wall surface 22 and perpendicular to the longitudinal direction on the other side in the longitudinal direction,
A third piezoelectric element part 10 is provided so as to be angularly displaceable with respect to the first piezoelectric element part 8, and (b31) has a width D2 larger than the width H and is a plate-shaped piece parallel to the inner wall surface 22. a third piezoelectric body 18; (b32) a pair of connecting portions 1 formed on both sides of the surface of the third piezoelectric body 18 in the width direction;
9a, 20a and each connecting portion 19a, 20a
A pair of third comb-shaped electrodes 19, 2 constituted by a plurality of vertically extending leg portions 19b, 20b that alternately face each other and intersect with each other.
(c) A voltage is applied between the pair of first comb-shaped electrodes 12, 13, and the second comb-shaped electrodes 15, 16 are connected to each other. A voltage is applied between the pair of third comb-shaped electrodes 19 and 20, and either one of the second or third piezoelectric element parts 9, 10 is rotated around the first or second axis 65, 66. A first step in which the first piezoelectric element portion 8 is angularly displaced and fixed in contact with the inner wall surface 22, and the first piezoelectric element portion 8 is curved and escapes into the relief recess 24 so as to be fixed in the longitudinal direction without being brought into contact with the inner wall surface 22. a second step in which the other of the second or third piezoelectric element portions 9, 10 is angularly displaced around the first or second axis 65, 66 and abuts against the inner wall surface 22 and is fixed; a fourth step of preventing said one of the second or third piezoelectric element portions 9, 10 from coming into contact with the inner wall surface 22; and a fifth step of extending the first piezoelectric element portion 8 in the longitudinal direction. , a sixth step of preventing the other of the second or third piezoelectric element portions 9, 10 from coming into contact with the inner wall surface 22, and power supply means for repeating the steps in this order. be.

Embodiment FIG. 2 is a perspective view showing the basic configuration of a moving body 7 in an embodiment of the present invention. A second piezoelectric element section 9 is arranged at one end of the first piezoelectric element section 8 in the moving direction. Second piezoelectric element section 9 of first piezoelectric element section 8
The third piezoelectric element section 10 is arranged at the other end on the opposite side. The first piezoelectric element section 8 includes a first piezoelectric body 11 made of a piezoelectric material, and a pair of comb-shaped electrodes 12 and 13 that are formed on one surface of the first piezoelectric body 11 and intersect with each other. is formed. The second piezoelectric element section 9 is formed flat and includes a second piezoelectric body 14 made of a piezoelectric material, and a pair of comb-shaped electrodes 15 and 16 that are formed on one surface of the second piezoelectric body and intersect with each other. ing. The third piezoelectric element section 10 includes a third piezoelectric body 18 made of a piezoelectric material, and a third piezoelectric body 18 made of a piezoelectric material.
It is formed flat and includes a pair of comb-shaped electrodes 19 and 20 which are formed on one surface of the piezoelectric body and which face each other and intersect with each other.

The first piezoelectric body 11, the second piezoelectric body 14, and the third piezoelectric body 18 are integrally formed piezoelectric bodies. The first connecting member 14a near the boundary between the first piezoelectric body 11 and the second piezoelectric body 14 and the second connecting member 18a near the boundary between the first piezoelectric body 11 and the third piezoelectric body 18
The piezoelectric body 11, the second piezoelectric body 14, and the third piezoelectric body 18 function as a fulcrum when curved as described later.

The mobile body 1 having such a configuration is roughly H
It is shaped like a letter and is flat. First piezoelectric element section 8
The width D1 is the width D1 of the second piezoelectric element section 9 and the third piezoelectric element section 1.
It is formed to be smaller than the width D2 of 0. In addition, the comb-shaped electrodes 12, 13, 15, 16, 19, and 20 have connecting portions 12a, 13a, and 13a, respectively, extending parallel to the moving direction.
15a, 16a, 19a, 20a and leg portions 12b, 13b, 15b, 16b, 19b that extend perpendicularly from each connecting portion and intersect with each other as shown in the second figure.
20b.

Lead zirconate titanate (hereinafter abbreviated as PZT), which is an inorganic material, is preferably used as the piezoelectric material forming the first piezoelectric body 11, the second piezoelectric body 14, and the third piezoelectric body 18. Composite materials of materials and polymeric materials are used. Composite materials include piezoelectric porcelain powder, such as barium titanate,
A polymer material containing lead zirconate titanate (PZT) or the like uniformly dispersed is suitable. As the polymeric material, vinylidene fluoride homopolymers and vinylidene fluoride copolymers such as vinylidene fluoride-trifluoroethylene copolymers are suitable.

3 is a plan view of an embodiment of the present invention, FIG. 4 is a front view thereof, FIG. 5 is a side view thereof, and FIG. 6 is an enlarged perspective view of part V of FIG. 4. It is. The movable body 7 is inserted into a hollow portion 23, which is a passage having a convex cross section and surrounded by an inner wall surface 22 of a guide body 21 extending in the left-right direction in FIGS. 3 and 4. The movable body 7 inserted into the hollow portion 23 is formed so as to be able to slide within the hollow portion 23 when no voltage is applied to each piezoelectric element portion. That is, the width D2 of the second piezoelectric element part 9 and the third piezoelectric element part 10 is formed smaller than the width D3 of the inner wall surface 22 of the guide body 21,
The thickness D4 of the first piezoelectric element part 8, the second piezoelectric element part 9, and the third piezoelectric element part 10 is the inner wall surface 22 of the guide body 21.
The height D5 is smaller than the height D5. Further, the width D1 of the first piezoelectric element part 8 is formed smaller than the width H of the escape recess 24 of the hollow part 23 of the guide body 21, and as will be described later, when the first piezoelectric element part 8 is curved, this escape recess is formed. 24 and movement cannot be prevented.

The first and second connecting members 14a and 18a can be angularly displaced around first and second axes 65 and 66, respectively, which are parallel to the inner wall surface 22 and perpendicular to the longitudinal direction.

FIG. 7 is a simplified block diagram showing the electrical configuration of the present driving piezoelectric device. Each electrode 12,1
Application and release of voltages to 3, 15, 16, 19, and 20 are fundamentally controlled in a unified manner by a single control circuit 25 in order to ensure smooth movement of the moving body 7.

FIG. 8 is a waveform diagram of the voltage applied to each piezoelectric element of the moving body 7, and FIG.
8 is a waveform diagram of the voltage applied to the first piezoelectric element section 8, and FIG. 8 is a waveform diagram of the voltage applied to the first piezoelectric element section 8. FIG.
FIG. 3 is a waveform diagram of voltage applied to. At this time, a voltage in a certain direction is applied between the comb-shaped electrodes 12, 13, 15, 16, 19, and 20 to polarize them, and a voltage having the above-mentioned waveform is applied. Comb-shaped electrodes 12, 13,
Voltages with different electrical polarities in the polarization direction are applied between the comb-shaped electrodes 15, 16, 19, and 20, and voltages with different electrical polarities are applied to the comb-shaped electrodes 12 and 13. ,16,19,
20 are also applied with voltages having different electrical polarities.

FIG. 9 is a diagram illustrating the operating state of the movable body 7 when the voltage shown in FIG. 8 is applied to each piezoelectric element of the movable body 7. With reference to FIGS. 8 and 9, the moving body 7
Explain the operation. The moving body 7 is in the initial state,
No voltage is applied to all the piezoelectric elements, and they are in the state shown in FIG. 91. When a voltage is applied to the second piezoelectric element portion 9 between time t1 and t2 in FIG. 8, the second piezoelectric element portion 9 bends in the direction of the arrow R as shown in FIG. The piezoelectric element portion 9 is pressed against and fixed to the inner wall surface 22 of the guide body 21. From time t2 to t
4, when a voltage is applied to the first piezoelectric element part 8 as shown in FIG. 82, the first piezoelectric element part 8 curves in the direction of arrow R as shown in FIG. The length in the moving direction is reduced by a length W in the guide body 21 toward the left in FIG. Next, when a voltage is applied to the third piezoelectric element section 10 as shown in FIG. 8 3 between time t4 and t5, the third piezoelectric element section 10 appears as shown in FIG.
is bent in the direction of arrow R, so that the third piezoelectric element portion 10 is pressed against and fixed to the inner wall surface 22 of the guide body 21. Next, between time t5 and t6, when the voltage application to the second piezoelectric element part 9 is canceled as shown in FIG. It separates from the inner wall surface 22 and becomes free. When the voltage application to the first piezoelectric element section 2 is released between time t6 and t7 as shown in FIG. 82, the first piezoelectric element section 2 is shown in FIG. 91 as shown in FIG. 96. Return to its original form. At this time, since the third piezoelectric element portion 4 is fixed to the inner wall surface 22 of the guide body 21, the movable body 1 slides and moves to the left in FIG. 9 by the aforementioned length W. When a voltage is applied to the second piezoelectric element part 3 as shown in FIG. 81 between time t7 and t8, the second piezoelectric element part 3 moves in the direction indicated by the arrow R as shown in FIG. 97.
The guide body 21 is bent in the direction shown in FIG. By repeating the above operations in this manner, the moving body 7 can move to the left in FIG. 9. In the above explanation, the moving body 7 was moved to the left in FIG. 9, but in the opposite direction (to the right in FIG. 9)
In order to move it to , it is sufficient to apply a voltage having the waveform shown in FIG. 8 to the third piezoelectric element section 10, and a voltage having the waveform shown in FIG. 8 to the second piezoelectric element section 9.

Such a moving body 7 is provided with a movement transmitting means (not shown) such as a rod for transmitting the movement to the outside of the guide body 5 as shown in the third figure.
This allows the moving body 7 to function as a linear motor.

In the above-mentioned embodiments, a composite material containing lead zirconate titanate (PZT) or the like is shown as a suitable example of the piezoelectric material, but the piezoelectric material may be formed only from piezoelectric porcelain such as PZT, or a second material may be used. The first piezoelectric body 11, the second piezoelectric body 14, and the third piezoelectric body 18 as shown in the figure do not have to be integrally formed at the same time. In this case, the joint portions 9a and 10a as shown in FIG. 2 may be constructed of a joint member that can be angularly displaced around an axis perpendicular to the moving direction. Further, in the embodiment shown in the second figure, a comb-shaped electrode is provided on one surface of each piezoelectric body, but in another embodiment of the present invention, comb-shaped electrodes may be provided on both surfaces of each piezoelectric body. Although the guide body 5 is illustrated as a groove block in FIG. 3, the present invention can be widely practiced using other configurations.

Furthermore, in the above embodiment, the first connecting member 14
a and the second connecting member 18a are made of the same material as the first piezoelectric body 11, for example.
The present invention is not limited to such a configuration, and the first connecting member 14a and the second connecting member 18a may be formed of an elastic material such as rubber.

According to the inventor's experimental results, the curvature of the first piezoelectric element section 8, second piezoelectric element section 9, and third piezoelectric element section 10 due to voltage application can be arbitrarily selected depending on the magnitude of the voltage. Therefore, a very large amount of movement W of the moving body 7 can be obtained in one cycle of operation. In fact, it was possible to obtain a movement amount that is about 10 times or more than the movement amount L in one cycle of the moving body 1 shown in the prior art.

The piezoelectric device according to the present invention can be used not only for precise positioning of tools and workpieces in numerically controlled machine tools, fine movement feeding of specimens in microscopes, fine angle adjustment of reflective mirrors in optical systems, and other various fine movement adjustment devices, but also for many other purposes. It can also be widely implemented in the technical field of

Effects As described above, according to the present invention, it is possible to realize a driving piezoelectric device having a much faster moving speed than the conventional technology. Furthermore, since there is no need to use a bimorph structure, the influence of the adhesion state and adhesive layer on performance in adhering a pair of piezoelectric bodies is eliminated, and the fear of peeling is also eliminated and a stable operating state is realized. In addition, since the piezoelectric element section is moved by bending and bending, the inner wall surface 22 of the guide body 21 and the piezoelectric element sections 8, 9, and 10 can be formed with lower precision than conventional techniques, improving work efficiency. be done.

Further, according to the present invention, the piezoelectric element portions 8, 9, 10
The curvature of the pair of comb-shaped electrodes 12, 13, 1 formed on the surfaces of the piezoelectric bodies 11, 14, 18, respectively
Due to voltage application between 5, 16, 19, and 20,
The direction of the applied voltage and the direction of deformation of the piezoelectric bodies 11, 14, 18 can be matched, and the legs 12b, 13b, 15b, 16b, 1 facing each other can
By adjusting the number and spacing of 9b and 20b, the degree of curvature can be adjusted.

Further, according to the present invention, the inner wall surface 22 of the guide body 21
An escape recess 24 is formed in the first piezoelectric element portion 8, so that the bending of the first piezoelectric element portion 8 is not hindered. First piezoelectric element section 8
Since the movable body 7 can be largely curved, the movable body 7 can be largely displaced by one drive.

[Brief explanation of the drawing]

FIG. 1 is a drive explanatory diagram of a movable body 1 according to the prior art, FIG. 2 is a perspective view of a movable body 7 according to the present invention, FIG. 3 is a plan view of an embodiment of the present invention, and FIG. 4 is a front view thereof. , FIG. 5 is a side view thereof, FIG. 6 is an enlarged perspective view of the portion V in FIG. 4, FIG. 7 is a block diagram showing the wiring state of the moving body 7, and FIG. A waveform diagram of voltages applied to the second piezoelectric element section 9 and the third piezoelectric element section 10, and FIG. 9 are explanatory diagrams of driving the moving body 7. 1, 7... Moving body, 2, 8... First piezoelectric element section, 3, 9... Second piezoelectric element section, 4, 10... Third piezoelectric element section, 5, 21... Guide body, 12 ,1
3, 15, 16, 19, 20... comb-shaped electrode, 25
...control circuit.

Claims (1)

[Claims for Utility Model Registration] (a) A longitudinal passage 23 formed by a pair of parallel inner wall surfaces 22 facing each other;
2, a guide body 21 is formed with a relief recess 24 having a predetermined width H and extending in the longitudinal direction.
(b) a movable body 7 housed in the passage 23; (b1) a first piezoelectric element part 8; (b11) having a width D1 smaller than the width H; Extending in the longitudinal direction, the inner wall surface 2
(b12) a pair of connecting portions 12a, 13 each formed on both sides of the surface of the first piezoelectric body 11 in the width direction so as to extend parallel to the longitudinal direction;
a, and a pair of first comb-shaped electrodes 12, 13 configured by a plurality of leg portions 12b, 13b extending vertically from each connecting portion 12a, 13a so as to alternately face each other and intersect with each other. (b2) a passage 23 with respect to the first piezoelectric element part 8;
Around a first axis 65 parallel to the inner wall surface 22 and perpendicular to the longitudinal direction on one side in the longitudinal direction,
A second piezoelectric element part 9 is provided so as to be angularly displaceable with respect to the first piezoelectric element part 8, and (b21) has a width D2 larger than the width H and is a plate-shaped member parallel to the inner wall surface 22. a second piezoelectric body 14; (b22) a pair of connecting portions 1 formed on both sides of the surface of the second piezoelectric body 14 in the width direction;
5a, 16a and each connecting portion 15a, 16a
A pair of second comb-shaped electrodes 15, 1 constituted by a plurality of vertically extending leg portions 15b, 16b that alternately face each other and intersect with each other.
(b3) a passage 23 with respect to the first piezoelectric element part 8;
Around the second axis 66 parallel to the inner wall surface 22 and perpendicular to the longitudinal direction on the other side in the longitudinal direction,
A third piezoelectric element part 10 is provided so as to be angularly displaceable with respect to the first piezoelectric element part 8, and (b31) has a width D2 larger than the width H and is a plate-shaped piece parallel to the inner wall surface 22. a third piezoelectric body 18; (b32) a pair of connecting portions 1 formed on both sides of the surface of the third piezoelectric body 18 in the width direction;
9a, 20a and each connecting portion 19a, 20a
A pair of third comb-shaped electrodes 19, 2 constituted by a plurality of vertically extending leg portions 19b, 20b that alternately face each other and intersect with each other.
(c) A voltage is applied between the pair of first comb-shaped electrodes 12, 13, and the second comb-shaped electrodes 15, 16 are connected to each other. A voltage is applied between the pair of third comb-shaped electrodes 19 and 20, and either one of the second or third piezoelectric element parts 9, 10 is rotated around the first or second axis 65, 66. A first step in which the first piezoelectric element portion 8 is angularly displaced and fixed in contact with the inner wall surface 22, and the first piezoelectric element portion 8 is curved and escapes into the relief recess 24 so as to be fixed in the longitudinal direction without being brought into contact with the inner wall surface 22. a second step in which the other of the second or third piezoelectric element portions 9, 10 is angularly displaced around the first or second axis 65, 66 and abuts against the inner wall surface 22 and is fixed; a fourth step of preventing said one of the second or third piezoelectric element portions 9, 10 from coming into contact with the inner wall surface 22; and a fifth step of extending the first piezoelectric element portion 8 in the longitudinal direction. , and a sixth step of preventing the other of the second or third piezoelectric element portions 9, 10 from contacting the inner wall surface 22.