JPH036153Y2 - - Google Patents

Description

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

BACKGROUND ART FIG. 1 is an operational diagram of a prior art piezoelectric device for driving a linear motor. The moving body 1 includes a first piezoelectric element section 2 extending in the moving direction, and a second piezoelectric element section 3 and a third piezoelectric element section 4 formed at both ends of the first piezoelectric element in the longitudinal direction. 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 direction of movement and is pressed against the inner wall surface 6 of the guide body 5 and fixed. 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.

Structure of the invention The invention provides piezoelectric bodies made of piezoelectric material on both sides of the common electrode plate in the thickness direction.
An electrode plate divided into three parts in the moving direction is attached to the piezoelectric body so as to face the common electrode plate through the piezoelectric body, and the common electrode plate, the piezoelectric body, and each of the three divided electrode plates A first piezoelectric element part that realizes a bimorph structure and is curved convexly or concavely in the thickness direction of the piezoelectric body; a second piezoelectric element part disposed at one end in the moving direction of the first piezoelectric element part; A third piezoelectric element part disposed at the other end in the moving direction of the first piezoelectric element part, the one end part of the first piezoelectric element part and the second piezoelectric element part are connected, and the first piezoelectric element part is divided into two parts. a first connecting member made of an electrode insulating material that surrounds between the separated electrode plate and the divided electrode plate of the second piezoelectric element portion and is capable of angular displacement around an axis perpendicular to the moving direction; The other end of the piezoelectric element part and the third piezoelectric element part are connected, and the space between the divided electrode plate of the first piezoelectric element part and the divided electrode plate of the third piezoelectric element part is surrounded. , a second connecting member made of an electrically insulating material that can be angularly displaced about an axis perpendicular to the direction of movement, and a first insulating member made of an insulating material and arranged to surround the first connecting member. a second insulating member made of an insulating material and arranged to surround the second connecting member; and a third insulating member made of an insulating material and arranged on the free end side of the second piezoelectric element part. A fourth insulating member made of an insulating material and disposed on the free end side of the third piezoelectric element, and a control for controlling the operation of the first piezoelectric element, the second piezoelectric element, and the third piezoelectric element. This is a driving piezoelectric device characterized by including a circuit.

In a preferred embodiment, the width in the thickness direction of the piezoelectric element of the third insulating member and the fourth insulating member is shorter than the width in the thickness direction of the piezoelectric element of the first insulating member and the second insulating member. It is characterized by

Embodiment FIG. 2 is a horizontal sectional view showing a state in which the movable body 7 according to the present invention is inserted into a guide body 8 such as a groove block, and FIG. 3 is a vertical sectional view of the configuration shown in FIG. 2. 4 is an axially perpendicular sectional view of the structure shown in FIG. 2, and FIG. 5 is an enlarged perspective view showing a portion V of FIG. 3 with a portion cut away. The moving body 7 includes a first piezoelectric element section 9 extending in the moving direction, and a second piezoelectric element section 10 disposed at one end of the first piezoelectric element section in the moving direction.
and a third piezoelectric element section 11 disposed at the other end of the first piezoelectric element section 9 in the moving direction. A first insulating member 12 is disposed at the connecting portion between the first piezoelectric element portion 9 and the second piezoelectric element portion 10, and a second insulating member 13 is disposed at the connecting portion between the first piezoelectric element portion 9 and the third piezoelectric element portion 11. is placed. A third piezoelectric element is provided on the free end side of the second piezoelectric element portion 10.
An insulating member 14 is arranged, and a fourth insulating member 15 is arranged on the free end side of the third piezoelectric element portion.

The width D1 in the thickness direction of the first piezoelectric element part 9 of the first insulating member 12 and the second insulating member 13 is the width D2 in the thickness direction of the first piezoelectric element part 9 of the third insulating member 14 and the fourth insulating member 14. It is formed approximately equal to or slightly longer than . Also, the first insulating member 12
and the second insulating member 13 is the movement space 1 of the guide body 8.
8 and move the movable body 7 into the movement space 1 of the guide body 8.
We will guide you within 8. The third insulating member 14 and the fourth insulating member 15 are connected to the second piezoelectric element section 1 as described later.
0 and the third piezoelectric element portion 11 when bent,
It is formed to be securely fixed to the inner wall surface 16 of the guide body 8.

FIG. 6 is a perspective view of the moving body 7 according to the present invention. The movable body 7 basically includes a common electrode plate 19 as a first electrode part, a pair of piezoelectric elements 20 fixed to both surfaces of the common electrode plate 19, and insulating members 12 to 15 arranged as described above. The piezoelectric element 20 is the common electrode 1
a pair of piezoelectric bodies 21, 22 made of a piezoelectric material, which are fixed to both surfaces of the piezoelectric bodies 9, and second electrode parts 23, 24, which are respectively fixed to the surfaces of the piezoelectric bodies 21, 22 on the side opposite to the surface facing the common electrode. including. Common electrode plate 1
9 is formed in a rectangular shape, and the piezoelectric bodies 21 and 22 are formed in a rectangular parallelepiped shape. Also, the second electrode portions 23, 24
are second electrode plates 23a, 23b, 23c, respectively;
It is divided into three parts 24a, 24b, and 24c. Reference numerals 21a, 21b, and 21c may be collectively indicated by reference numeral 21, and reference numerals 22a, 22b, and 22c may be collectively indicated by reference numeral 22.

The first piezoelectric element portion 9 is a portion 19 of the common electrode plate 19.
a, portions 21a and 22a of the piezoelectric bodies 21 and 22, and portions 23a and 24a of the second electrode plates 23 and 24. The second piezoelectric element section 10 is a common electrode plate 1
9 portion 19b and piezoelectric bodies 21 and 22 portion 21
b, 22b and the portion 23 of the second electrode plate 23, 24
b, 24b. The third piezoelectric element portion includes a portion 19c of the common electrode plate 19 and piezoelectric bodies 21 and 22.
21c, 22c and portions 23c, 24c of the second electrodes 23, 24. A first connecting member 25 that connects the first piezoelectric element section 9 and the second piezoelectric element section 10 includes a common electrode plate 19 and a piezoelectric body 21, 22.
It has a structure in which the second electrode plates 23 and 24 are missing. The second connecting member 26 that connects the first piezoelectric element section 9 and the third piezoelectric element section 11 has the same configuration as the first connecting member.

That is, the first connecting member 25 includes the divided electrode plates 23a and 24a of the first piezoelectric element section 9 and the divided electrode plates 23b and 24b of the second piezoelectric element section 10.
surround the space between Further, the second connecting member 26 is connected to the first connecting member 26.
Divided electrode plates 23a, 24a of piezoelectric element section 9
and the divided electrode plate 23 of the third piezoelectric element section 11
c and 24c. These first and second connecting members 25, 26 are made of electrically insulating material.

The first insulating member 12 is arranged to surround the first connecting member 25 in a direction perpendicular to the moving direction, and the second insulating member 13 is arranged to surround the second connecting member 26 in a direction perpendicular to the moving direction. . A third insulating member 14 is arranged on the free end side of the second piezoelectric element section 10, and a fourth insulating member 15 is arranged on the free end side of the third piezoelectric element section 11.

The piezoelectric bodies 21 and 22 are made of inorganic materials.
PZT (lead zirconate titanate) is preferably used, but also, for example, a composite of an inorganic material and a polymeric material. The composite material is preferably a polymeric material containing uniformly dispersed piezoelectric porcelain powder, such as barium titanate or lead zirconate titanate PZT powder, and the polymeric material is preferably a homopolymer of vinylidene fluoride or foam. Vinylidene chloride-3
Vinylidene fluoride copolymers such as fluorinated ethylene copolymers are preferred. The first insulating member 12 to the fourth
As the material of the insulating member 15, for example, insulating plastics or ceramics can be used.

FIG. 7 is a simplified block diagram showing the electrical configuration of this embodiment. Common electrode plate 19 and second
Electrode plates 23a, 24a, 23b, 24b, 23
c and 24c are basically a single control circuit 27 in order to obtain a smooth driving state during driving, which will be described later.
is uniformly controlled by Further, during this driving, voltages with different electrical polarities are applied to the common electrode plate 19 and the second electrode plates 23 and 24.

FIG. 8 is a waveform diagram of voltages applied to each electrode shown in FIG. 7. FIG. 8 1 shows the common electrode plate 19
3B and the second electrode plates 23b and 24b, that is, the waveform of the voltage applied to the second piezoelectric element section 10. FIG. 8 shows the waveform of the voltage applied between the common electrode plate 19c and the second electrode plates 23a and 24a, that is, to the first piezoelectric element section 9. In FIG. FIG. 8 shows the waveform of the voltage applied between the common electrode plate 19c and the second electrode plates 23c and 24c, that is, to the third piezoelectric element section 11.

FIG. 9 is a diagram illustrating the operating state of each piezoelectric element portion and the moving body 7 when a voltage having the waveform shown in FIG. 8 is applied to each electrode plate. The operating state of the moving body 1 will be explained with reference to FIGS. 8 and 9. In the initial state, no voltage is applied to each electrode plate, and the ninth
Assume that the state is as shown in FIG. When a voltage is applied to the second piezoelectric element portion 10 at time t1 as shown in FIG. 8, it bends upward in FIG. 9 as shown in FIG. 8 inner wall surface 1
6 and fixed. When a voltage is applied to the first piezoelectric element section 9 at time t2 as shown in FIG.
As shown in FIG. 3, it curves upward in FIG. At this time, since the third insulating member 14 is fixed to the inner wall surface 16 of the guide body 8 shown in the second figure, the movable body 7 is moved to the left in FIG. 9 by a predetermined length W as shown in FIG. It will shrink to.

Next, as shown in FIG. 8, when a voltage is applied to the third piezoelectric element section 11 at time t4, the third piezoelectric element section 11 is bent upward in FIG. 9, as shown in FIG. 9. At this time, the fourth insulating member 15 is crimped and fixed to the inner wall surface 16 of the guide body 8 shown in the second figure. When the voltage application to the second piezoelectric element section 10 is released at time t5 as shown in FIG. 81, the second piezoelectric element section 10 is released from the bent state and returns to its original shape as shown in FIG. 95. That is, the inner wall surface 1 of the guide body 8 shown in the second figure
It is released from the fixed state to 6 and becomes in a state where it can freely slide.

Next, as shown in FIG. 82, when the voltage application to the first piezoelectric element part 9 is released at time t6, the first piezoelectric element part 9 is released from the curved state and returns to its original shape as shown in FIG. 96. vinegar. At this time, since the third piezoelectric element portion 11 remains bent, the fourth insulating member 15 is fixed to the inner wall surface 16 of the guide body 8 shown in the second figure, so that the movable body 7 is moved to the left in FIG. It will be extended by the length W. At this time, the moving body 7 has moved by a length W to the left in FIG. 9 compared to the position in FIG. 91. Next, as shown in FIG. 8 1, when a voltage is applied to the second piezoelectric element section 10 at time t7, the second piezoelectric element section 10 is bent upward in FIG. 9 as shown in FIG. The third insulating member 14 is crimped and fixed to the inner wall surface 16 of the guide body 8 shown in the second figure. Next, as shown in FIG. 8, time t8
When the voltage application to the third piezoelectric element section 11 is canceled at
The third piezoelectric element portion 11 returns to its original shape from the bent state and enters the state shown in FIG. 92.

By repeating the processes shown in FIG. 9 2 to FIG. 9 7 as described above, the movable body 7 can be moved to the left in FIG. 9 by an arbitrary distance. To reverse the moving direction of the moving body 7 (to the left in FIG. 9), apply a voltage with the waveform shown in FIG. What is necessary is to apply the voltage to the second piezoelectric element section 10. In such a moving body 7, the above-described movement of the moving body 7 is transmitted to the outside of a guide body 8 shown in the second figure. A transmission means (not shown), for example a rod, is attached, by means of which the moving body 7 can be adapted to function as a linear motor. Furthermore, although the guide body 8 is shown as a groove block in this embodiment, the guide body 8 may have other configurations.

According to the inventor's experimental results, a pair of piezoelectric elements 2
0 is divided into three parts and moved by bending each piezoelectric element part, the bending ratio of each piezoelectric element part can be set arbitrarily, and the piezoelectric device shown in the prior art can be moved. The amount of movement was approximately 10 times greater than the amount of movement in one cycle.

FIG. 10 is a plan view of a moving body 7 according to another embodiment of the present invention, FIG. 11 is a front view of FIG. 10, and FIG. 12 is a side view of FIG. 11. This embodiment is similar to the embodiment shown in Figure 6, and corresponding parts are given the same reference numerals. What should be noted is that the outer surfaces of the first insulating member 12 and the second insulating member 13 are formed into smooth arcuate surfaces. As described above, the first insulating member 12 and the second insulating member 13
slides along the inner wall surface 18 of the guide body 8 shown in the second figure, and by forming the shape as in this embodiment, the coefficient of sliding friction can be lowered.

FIG. 13 is a plan view of a moving body 7 in still another embodiment of the present invention, FIG. 14 is a front view of FIG. 13, and FIG. 15 is a view taken from the cutting plane line - of FIG. FIG. This embodiment is similar to the embodiment shown in Figure 6, and corresponding parts are given the same reference numerals. What should be noted is the first insulating member 12
A notch portion 28 forming a concave groove parallel to the moving direction is provided on the side portion of each piezoelectric element portion of the second insulating member 13 in a direction perpendicular to the thickness direction. A conductive wire 29 that electrically connects each electrode of each piezoelectric element to a control circuit 27 as shown in FIG. 7 can be inserted and fixed into this notch 28. By doing this, the conductive wire 29 can be connected to the inner wall surface 1 of the guide body 8 shown in the second figure.
The conductive wire 29 can be held so as not to come into contact with the movable body 7, and the conductive wire 29 will move as the movable body 7 moves. Therefore, it becomes easy to move the movable body 7 arbitrarily, and the bending of the conductive wire 29 due to the movement and the inner wall surface 1 of the guide body 8 shown in the second figure
6 can be reduced, and cutting of the conductive wire 29 can be prevented.

The piezoelectric device according to the present invention can be used not only for positioning tools and workpieces in numerically controlled NC machine tools, fine movement feeding of specimens in microscopes, fine angle adjustment of optical system reflectors and other telescopes, and various other fine movement adjustment devices. It can also be widely implemented in other technical fields.

Further, in the above-mentioned embodiment, the first connecting member 25 and the second connecting member 26 were composed of the common electrode plate 19 and the piezoelectric bodies 21 and 22, but the present invention is not limited to such a composition. The first and second connecting members 25, 26 are connected by an elastic body or the like.
may be formed.

Effects As described above, according to the present invention, the moving body is constructed from three piezoelectric elements having a bimorph structure, and is moved by bending each piezoelectric element, so that the moving speed can be significantly increased. It is possible to achieve a significant increase. Furthermore, machining of the piezoelectric element and the inner wall surface of the guide body can be performed with lower precision than in the past. In addition, by providing an insulating member, it is possible to separate the electrode plate of the piezoelectric element from the inner wall surface of the guide body, which reduces wear and fatigue over time and provides stable operating conditions. can.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the drive of the moving body 1 of the prior art, FIG. 2 is a horizontal sectional view of an embodiment of the present invention, FIG. 3 is a vertical sectional view of the embodiment of FIG. 2, and FIG. 2 is an axially perpendicular sectional view of the embodiment shown in FIG. 2, FIG. 5 is an enlarged perspective view partially cut away from part V in FIG. 3, and FIG. 6 is a perspective view of the movable body 7 of the embodiment shown in FIG. FIG. 7 is a block diagram showing the electrical configuration of the embodiment shown in FIG. 2, and FIG. 8 is a waveform diagram of voltages applied to the first piezoelectric element section 9, the second piezoelectric element section 10, and the third piezoelectric element section 11. 9 is a diagram explaining the driving state of the moving body 7, FIG. 10 is a plan view of another embodiment of the present invention, FIG. 11 is a front view of FIG. 10, and FIG. 12 is a side view of FIG. 11. 13 is a plan view of still another embodiment of the present invention, FIG. 14 is a front view of FIG. 13, and FIG. 15 is a side sectional view taken along the section line - of FIG. 14. 7... Moving body, 8... Guide body, 9... First piezoelectric element section, 10... Second piezoelectric element section, 11... Third
Piezoelectric element portion, 12...first insulating member, 13...second insulating member, 14...third insulating member, 15...fourth insulating member, 16...inner wall surface, 25...first connecting member, 26...Second connecting member, 28...Notch portion.

Claims (1)

[Claims for Utility Model Registration] (1) A piezoelectric body made of a piezoelectric material is provided on both sides in the thickness direction of the common electrode plate, and the piezoelectric body has an electrode plate divided into three in the direction of movement,
It is attached so as to face the common electrode plate through the piezoelectric body, and a bimorph structure is realized by the common electrode plate, the piezoelectric body, and each of the three divided electrode plates, and the piezoelectric body has a convex or concave shape in the thickness direction. a first piezoelectric element section curved in the direction of the movement; a second piezoelectric element section disposed at one end of the first piezoelectric element section in the moving direction; and a third piezoelectric element section disposed at the other end of the first piezoelectric element section in the moving direction. a piezoelectric element section, the one end of the first piezoelectric element section and the second piezoelectric element section are connected, the divided electrode plate of the first piezoelectric element section and the divided electrode of the second piezoelectric element section; A first connecting member made of an electrically insulating material that surrounds the space between the plates and is movable around an axis perpendicular to the moving direction, and connects the other end of the first piezoelectric element and the third piezoelectric element. and an electrically insulating material that surrounds between the divided electrode plate of the first piezoelectric element part and the divided electrode plate of the third piezoelectric element part and is capable of angular displacement around an axis perpendicular to the moving direction. a first insulating member made of an insulating material and arranged to surround the first connecting member; and a first insulating member made of an insulating material so as to surround the second connecting member. A third insulating member made of an insulating material and placed on the free end side of the second piezoelectric element part; A third insulating member made of an insulating material and placed on the free end side of the third piezoelectric element part. A piezoelectric device for driving, comprising: a fourth insulating member disposed in the insulating member; and a control circuit that controls operations of the first piezoelectric element, the second piezoelectric element, and the third piezoelectric element. (2) The width in the thickness direction of the piezoelectric element of the third insulating member and the fourth insulating member is made shorter than the width in the thickness direction of the piezoelectric element of the first insulating member and the second insulating member. A driving piezoelectric device according to claim 1, characterized in that it is a utility model.