JP2000174352A - Piezoelectric-crystal element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laminated piezoelectric-crystal element which is easy to manufacture and superior conversion efficiency and a method for the manufacture of the piezoelectric-crystal element. SOLUTION: Electrodes 11a and 12a are formed on the surfaces of two sheet- like piezoelectric elements 11 and 12 respectively, and the elements are laminated. The laminate is wrapped around a shaft 13 and formed into a cylinder and is fired and polarized to form a piezoelectric-crystal element 10. A shaft obtained by bonding together a plurality of plate-like bodies separated in the direction of the displacement of the piezoelectric-crystal element, or a plurality of segments cut off in the direction of displacement with adhesive which is thermally decomposed at a temperature lower than firing temperature into cylindrical shape, or a shaft the surface of which is coated with coating agent is used for the shaft. Thus, the wrapping work is facilitated, and after firing, the adhesive is decomposed by heat to cause the plurality of the plate-like bodies or segments comprising the shaft to come apart, or the coating agent is evaporated so that the shaft can be removed. As a result, the shaft will not interfere with the displacement of the piezoelectric-crystal element 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a piezoelectric transducer and a method for manufacturing the same.

[0002]

2. Description of the Related Art An actuator using a piezoelectric transducer has a high conversion efficiency for converting supplied electric energy into a driving force, is small in size and light in weight, generates a large driving force, and has a high driving force. Therefore, it has been used for driving and positioning of driven members of cameras, measuring instruments, and other precision machines.

[0003] As a piezoelectric conversion element as a driving source used in such an actuator, there is an element in which a plurality of unit piezoelectric elements are stacked. This is because the displacement in the thickness direction generated in the unit piezoelectric element is taken out as large as possible.

[0004] Piezoelectric transducers composed of a plurality of unitary piezoelectric elements laminated require the complicated steps of providing electrodes on the surface of each unit element, laminating and bonding, and connecting the electrodes of each layer. It is expensive because it is manufactured after passing through.

As another type of piezoelectric transducer, there is a single-layer hollow cylindrical piezoelectric transducer.

[0006] Even though the hollow cylindrical piezoelectric conversion element is characterized by relatively high mechanical strength, it is necessary to increase the electric field strength in order to increase the generated displacement. Therefore, when there is a restriction on the voltage applied to the piezoelectric conversion element, the thickness of the piezoelectric conversion element must be reduced to increase the electric field strength. That is, there is an inconvenience that the mechanical strength of the piezoelectric conversion element is reduced when the displacement to be generated is increased.

As a countermeasure against this, a laminated body formed by laminating a thin plate-shaped first piezoelectric element having electrodes formed thereon and a thin plate-shaped second piezoelectric element having electrodes formed thereon is wound into a cylindrical shape. The piezoelectric conversion element thus formed has been proposed by the present applicant (see Japanese Patent Application Nos. 10-199001 and 10-254462).

[0008]

However, in a piezoelectric transducer in which a laminated body in which two thin plate-like piezoelectric elements on which electrodes are formed is wound in a hollow cylindrical shape, the piezoelectric transducer is deformed during heat treatment. There are inconveniences such as doing. As a countermeasure, a configuration in which the two thin plate-like piezoelectric element laminates described above are wound around a central axis has been proposed. In the configuration with the central axis, displacement generated in the piezoelectric transducer is hindered by the central axis. It has become clear that there is a disadvantage that sufficient displacement cannot be generated. An object of the present invention is to solve the above problems.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and the invention of claim 1 is based on a piezoelectric ceramic mainly composed of PZT (PbZrO ₃ .PbTiO ₃ ) having electrodes formed on the surface. A piezoelectric conversion element characterized in that a thin plate-shaped piezoelectric element is wound around a central axis formed by bonding a plurality of members with an adhesive that is thermally decomposed at a temperature not higher than the firing temperature of the piezoelectric element, thereby forming a cylindrical shape. is there.

[0010] The thin plate-shaped piezoelectric element is a laminated body in which first and second piezoelectric elements having electrodes formed on the surface are laminated.

Further, the plurality of members constituting the center shaft are a plurality of disk-shaped plate members separated in the direction of displacement of the piezoelectric transducer made of a high melting point material, and the center shaft is formed of the plurality of disk-shaped members. It is preferable to form a cylindrical or column-shaped central shaft by laminating the plate members in the axial direction and bonding them with an adhesive that decomposes at a temperature lower than the firing temperature of the piezoelectric element.

The plurality of members constituting the center shaft are a plurality of segments obtained by cutting a cylinder or a column made of a high melting point material along the direction of displacement of the piezoelectric transducer, and the center shaft is formed by cutting the plurality of segments. It is also possible to use a cylindrical or cylindrical central shaft that is formed by bonding with an adhesive that is thermally decomposed below the firing temperature of the piezoelectric element.

[0013] The center shaft may be a fired center shaft formed of the same material as the thin plate-shaped piezoelectric element.

According to a fifth aspect of the present invention, there is provided a thin plate-shaped piezoelectric element made of a piezoelectric ceramic mainly composed of PZT (PbZrO ₃ .PbTiO ₃ ) having electrodes formed on the surface, and the surface is heated at a temperature lower than the firing temperature of the piezoelectric element. A piezoelectric conversion element characterized in that it is wound around a central axis made of a high melting point material coated with a thermally decomposable coating agent to form a cylindrical shape.

[0015] The center shaft may be a fired center shaft formed of the same material as the thin plate-shaped piezoelectric element.

According to a seventh aspect of the present invention, there is provided a thin plate-shaped P
Forming electrodes on the surfaces of first and second piezoelectric elements made of piezoelectric ceramics containing ZT (PbZrO ₃ .PbTiO ₃ ) as a main component, and forming an electrode forming surface of the first piezoelectric element and a second piezoelectric element. Laminating such that the electrode non-forming surfaces of the element are opposed to each other, winding a plurality of members around a central axis configured by bonding with an adhesive that is thermally decomposed below the firing temperature of the piezoelectric element, and forming a cylindrical body. A step of firing the formed cylindrical body at a predetermined temperature, and a step of applying a predetermined voltage between the electrodes of the fired cylindrical body to polarize the formed cylindrical body. is there.

[0017] The method of manufacturing the piezoelectric transducer is as follows.
Further, a plurality of disk-shaped plates are formed as a plurality of members that are separated from each other in the direction of displacement of the piezoelectric transducer made of a high melting point material, and the disk-shaped plates are laminated in the axial direction to form a piezoelectric element. A center axis forming step of forming a cylindrical or columnar shape by bonding with an adhesive that decomposes at a temperature lower than the firing temperature of the element can be included.

Further, the method for manufacturing a piezoelectric transducer may further include a step of removing the center axis after firing at a predetermined temperature.

Further, the method for manufacturing the piezoelectric transducer is as follows.
Further, an adhesive that cuts a cylinder or a cylinder made of a high melting point material along the direction of displacement of the piezoelectric conversion element as a plurality of members to form a plurality of segments, and thermally decomposes the segments at a firing temperature of the piezoelectric element or lower. And a center shaft forming step of forming a cylindrical or columnar shape by adhering.

Further, the method for manufacturing a piezoelectric transducer may further include a step of removing the center axis after firing at a predetermined temperature.

According to a twelfth aspect of the present invention, a thin plate is formed.
PZT (PbZrO_Three・ PbTiO _Three) As the main component
Table of first and second piezoelectric elements made of piezoelectric ceramics
Forming electrodes on the surface and forming electrodes of the first piezoelectric element
Product so that the surface and the electrode-free surface of the second piezoelectric element face each other.
A layer that is thermally decomposed below the firing temperature of the piezoelectric element.
Wrapped around a central shaft covered with
And firing the formed tubular body at a predetermined temperature.
And applying a predetermined voltage between the electrodes of the fired tubular body for separation.
And a step of polarizing the piezoelectric element.
It is a manufacturing method.

The method for manufacturing the piezoelectric transducer is as follows:
Further, after firing at a predetermined temperature, a step of removing the center shaft can be included.

[0023]

Embodiments of the present invention will be described below.

[First Embodiment] FIGS. 1 to 3 are views for explaining the structure and manufacturing process of a piezoelectric transducer according to a first embodiment of the present invention. FIG. 1 shows the appearance of the piezoelectric transducer. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG. 1, and FIG. 3 is a perspective view of the piezoelectric transducer in a manufacturing process.

As shown in FIGS. 1 and 2, the piezoelectric transducer 10 has a thin plate-like first piezoelectric element 11 and a second piezoelectric element 12 having electrodes 11a and 12a formed on the surface thereof, respectively.
Are laminated on the electrode forming surface of the first piezoelectric element 11 with the non-electrode forming surface of the second piezoelectric element 12 opposed thereto, and the laminated body is wound around the central shaft 13 to form a cylindrical shape. .

In FIG. 2, there is a space between the center shaft and the end of the wound piezoelectric element. This is because the thickness of the piezoelectric element is enlarged for the sake of explanation, and actually, Since the piezoelectric element has an extremely thin plate shape as described later, there is almost no space between the center shaft and the end of the wound piezoelectric element.

As shown in FIG. 1, when the first piezoelectric element 11 and the second piezoelectric element 12 are stacked, the end of the electrode 11a of the element of the first piezoelectric element 11 located below is exposed. Therefore, a notch 12b is formed at the end of the second piezoelectric element 12 located on the upper side, and the lower piezoelectric element 1
It is configured so that a lead wire can be connected to one electrode 11a.

Next, the manufacturing process will be described. First, as a material of the piezoelectric elements 11 and 12, PZT (PbZr
Piezoelectric ceramics whose main component is O ₃ .PbTiO ₃ ) are used. This ceramic powder is mixed with a solvent, a dispersant, a binder, a plasticizer, and the like, and is formed into a uniform plane using a blade or the like to have a constant thickness, for example, 20 to 100 μm.
Stretch to thickness. When the solvent is evaporated and dried, a flexible sheet called green sheet can be obtained.

The PZT includes Sr, Sn, Sb, M
A small amount of a modifying element such as n can be added.

Next, a paste-like electrode material, for example, a Pt-based electrode material or an Ag-Pd-based electrode material is coated on the surface of the green sheet by 1 to several μm by means such as screen printing. Printing is performed to a thickness to form the electrodes 11a and 12a.

The piezoelectric element on which the electrodes are formed by printing is cut into a predetermined size, and the second piezoelectric element 12 on which the electrode 12a is formed on the first piezoelectric element 11 on which the electrode 11a is formed.
Are laminated and laminated. At this time, the first piezoelectric element 1
The electrode-free surface of the second piezoelectric element 12 is laminated on the first electrode-forming surface so as to face each other. In addition, a notch 12b is formed at a corner of the second piezoelectric element 12.

Next, the laminated sheet-like piezoelectric element 1
1 and 12 are wound around the center shaft 13 to form a cylindrical body. Here, the center shaft 13 will be described.

The center shaft 13 is formed, for example, by firing a piezoelectric ceramic cylinder mainly composed of PZT, and cutting this into a thin plate having a thickness t (for example, about 1 mm) with a dicing saw as shown in FIG. To form a disc-shaped plate 13P having a hole in the center. Furthermore, this disk-shaped plate 13P
Is inserted into a working shaft 15 having an outer diameter substantially equal to the inner diameter at the center thereof, and laminated. FIG. 5 shows this state.

Next, the outside of the laminated disk-shaped plate body is wound around with a tape or the like and temporarily fixed, the work shaft 15 is pulled out, and for example, a cyanoacrylate adhesive is poured into the inner surface of the work shaft 15, and the disk is poured. The plates 13P are adhered to each other to form a cylinder, and the temporary fixing tape is removed to complete the center shaft 13.

The sheet-like piezoelectric elements 11 and 12 previously laminated are wound around the center shaft 13 to form a cylindrical body, which is fired under a predetermined temperature condition to form the electrodes 11a and 1a.
When a lead wire is connected to 2a and a predetermined DC high voltage is applied for polarization, the piezoelectric conversion element 10 is completed. After this,
It is cut into a desired length, for example, about 5 mm, and used as a drive element of an actuator.

As shown in FIG. 6, for example, as shown in FIG. 6, the temperature is gradually raised to 500 ° C. over about 5 hours, and after baking at 500 ° C. for a certain time, the temperature is gradually increased to 1200 ° C. 9 hours after the beginning. To increase the temperature. In addition, 120
After baking at 0 ° C. for about 0.3 hours, it is cooled to room temperature over about 6 hours.

The direction of polarization is the thickness direction of the sheet-shaped piezoelectric element. For example, in a 60 ° C. environment, a voltage of 1.5 kV / mm is applied between the electrodes 11a and 12a for 20 minutes for polarization. By polarizing the piezoelectric element, displacement can be generated in the piezoelectric elements 11 and 12 in the direction of the cylindrical axis.

The sheet-like piezoelectric elements 11 and 1 are mounted on the center shaft 13.
2 and wound and fired, the adhesive that has bonded the disc-shaped plates 13P constituting the central shaft 13 to each other is thermally decomposed during the firing process, and the disc-shaped plates 13P are displaced in the displacement direction of the piezoelectric transducer 10. On the other hand, since they are separated from each other, even if the center shaft 13 is provided inside the piezoelectric conversion element 10, the displacement generated in the piezoelectric conversion element 10 is not hindered.

The above-mentioned center shaft 13 is not limited to a cylinder made of piezoelectric ceramics, but may be made of other ceramics. Alternatively, a cylinder made of other high melting point material such as carbon, molybdenum, and tungsten may be used. it can. Also, the shape is not limited to a cylinder, and may be a cylindrical shape or any other appropriate cylindrical or columnar shape.

FIG. 7 shows a piezoelectric transducer (a) having a center axis separated from the displacement direction of the piezoelectric transducer described above, a piezoelectric transducer element (b) without a center axis, and a normal center axis (displacement). It is a figure which shows the relationship between the applied voltage and the displacement about the piezoelectric conversion element (c) which has a center axis | shaft (separate to a direction).

As is apparent from the figure, the piezoelectric transducer (a) having the central axis separated from the displacement direction, which is the piezoelectric transducer of the first embodiment, is the piezoelectric transducer (b) having no central axis. ) Shows the relationship between applied voltage and displacement very close to
11 at most compared to the piezoelectric transducer (b) without the central shaft
% Displacement loss. On the other hand, it is shown that the piezoelectric transducer (c) having a normal center axis has a displacement loss of up to 34% as compared with the piezoelectric transducer (b) without the center axis.

In addition, a piezoelectric conversion element having no center axis has a large deformation during firing and a large possibility of delamination of a laminated sheet-like piezoelectric element. And the ordinary piezoelectric element having a center axis have a small deformation at the time of firing, and the possibility of delamination of the laminated piezoelectric elements is small.

Further, the strength (easiness of cracking) in the radial direction of a cylindrical piezoelectric element is determined by the piezoelectric element having a central axis separated from the displacement direction and the piezoelectric element having a normal central axis. , And is less likely to break as compared to a piezoelectric conversion element without a central shaft. Needless to say, the ease with which the stacked piezoelectric elements are rolled into a cylindrical shape is much easier with the central shaft.

In the above-described piezoelectric transducer of the first embodiment, after firing, the center axis is separated separately, so that the separated center axis can be removed.

[Second Embodiment] A second embodiment is a thin plate-like structure having electrodes 11a and 12a formed on the surface, similarly to the above-described piezoelectric transducer of the first embodiment. First piezoelectric element 11 and second piezoelectric element 12
Are laminated on the electrode forming surface of the first piezoelectric element 11 with the electrode non-forming surface of the second piezoelectric element 12 facing the electrode (see FIGS. 1 to 3). After winding around the central shaft to form a cylindrical shape, firing, and then removing the central shaft. Since the configuration of the central shaft is different and the other components remain the same, only the configuration of the central shaft will be described, and description of the other components will be omitted.

FIGS. 8 and 9 are views for explaining the configuration of the center axis of the piezoelectric transducer according to the second embodiment. FIG.
FIG. 9 is a perspective view showing the configuration of FIG. 9. FIG. 9 illustrates a state in which the central shaft 21 is removed from a piezoelectric conversion element tubular body formed by winding the thin plate-shaped first piezoelectric element 11 and second piezoelectric element 12 around the central shaft 21. It is sectional drawing.

The center shaft 21 is formed, for example, by firing a cylinder of piezoelectric ceramics containing PZT as a main component, and sintering the cylinder in parallel with the axial direction as shown in FIG. 8, that is, along the displacement direction of the piezoelectric transducer. (In this example, eight) segments 21
a, 21b, 21c, 21d, 21e, 21f, 21
g and 21h are cut with a dicing saw or the like. Next, these segments 21a to 21h are adhered with, for example, a cyanoacrylate-based adhesive to form a cylindrical shape again.

The laminated sheet-like piezoelectric elements 11 and 12 (see FIG. 3) are wound around the center shaft 21 to form a cylindrical body, which is fired under a predetermined temperature condition, and is formed on the electrodes 11a and 12a. A lead wire is connected and a predetermined high DC voltage is applied for polarization.

The segments 21a-2 constituting the center shaft 21
Since the adhesive bonding 1h is thermally decomposed in the firing process, and the segments 21a to 21h are separated separately,
The segments 21a to 21h can be easily removed from the piezoelectric element tubular body formed by winding the piezoelectric elements 11 and 12, and a piezoelectric element without a center shaft can be formed.

The above-mentioned center shaft 21 is not limited to a cylinder made of piezoelectric ceramics, but may be made of other ceramics. Alternatively, a cylinder made of another high melting point material such as carbon, molybdenum, or tungsten may be used. it can. Also, the shape is not limited to a cylinder, and may be a cylindrical shape or any other appropriate cylindrical or columnar shape.

[Third Embodiment] In the third embodiment, like the piezoelectric transducer of the second embodiment described above, a thin plate having electrodes 11a and 12a formed on the surface, respectively. First piezoelectric element 11 and second piezoelectric element 12
Are laminated on the electrode forming surface of the first piezoelectric element 11 with the electrode non-forming surface of the second piezoelectric element 12 facing the electrode (see FIGS. 1 to 3). After winding around the central shaft to form a cylindrical shape, firing, and then removing the central shaft. Since the configuration of the central shaft is different and the other components remain the same, only the configuration of the central shaft will be described, and description of the other components will be omitted.

FIG. 10 is a view for explaining the configuration of the center axis of the piezoelectric transducer according to the third embodiment. As shown in FIG.
The center shaft 31 is formed by applying a coating agent made of a material that is thermally decomposed on the surface of the core shaft 31a to form a coating 32.

The laminated sheet-like piezoelectric elements 11 and 12 (see FIG. 3) are wound around a central shaft 31 on which a coating 32 is formed by applying the coating agent to form a cylindrical body. This is fired under a predetermined temperature condition, a lead wire is connected to the electrodes 11a and 12a, and a predetermined high DC voltage is applied to polarize the electrode.

The coating film 32 of the coating agent on the surface of the central shaft 31 is thermally decomposed and evaporated during the firing process, and is placed between the piezoelectric element tubular body formed by winding the piezoelectric elements 11 and 12 and the core shaft 31a. Since the gap is formed, the core shaft 31a, that is, the center shaft 31 without the coating 32 of the coating agent can be easily removed, and a piezoelectric conversion element having no center shaft can be formed. The coating agent is selected from materials that are thermally decomposed at a temperature as close as possible to the firing temperature.

The core shaft of the above-mentioned center shaft is not limited to a cylinder made of piezoelectric ceramics, but may be made of other ceramics, or a cylinder made of other high melting point material such as carbon, molybdenum and tungsten. You can also. Also, the shape is not limited to a cylinder, and may be a cylindrical shape or any other appropriate cylindrical or columnar shape.

Next, an example of the configuration of an actuator using the above-described piezoelectric transducer will be described with reference to FIGS.

FIG. 11 is a sectional view showing the structure of the actuator. In FIG. 11, 44 is a base, 45, 46, 4
Reference numeral 7 denotes a support block, and 48 denotes a drive shaft. The drive shaft 48 is supported by the support block 46 such that it can be displaced in the axial direction (the direction of the arrow a and the direction opposite thereto) by the axial displacement generated in the piezoelectric transducer 40. It is movably supported by a block 47.

Reference numeral 40 denotes a cylindrical piezoelectric transducer manufactured by the above-described manufacturing method. One end of the piezoelectric transducer 40 is adhesively fixed to a support block 45, and the other end is a drive shaft 48.
Adhesively fixed to one end.

Reference numeral 54 denotes a drive pulse generating circuit for generating a sawtooth pulse having a gentle rising portion and a rapid falling portion, or a rapid rising portion and a gentle falling portion. Numeral 54 supplies a drive pulse between the electrodes 41 a and 42 a of the piezoelectric conversion element 40 to drive the piezoelectric conversion element 40.

Numeral 49 denotes a slider, and the slider 49 and the drive shaft 48 are frictionally coupled by an appropriate frictional force. FIG.
FIG. 11 is a cross-sectional view showing a configuration of a frictional coupling portion between the slider 49 and the drive shaft 48. The drive shaft 48 penetrates the slider 49, and an opening 49a is formed in a lower portion of the slider 49 through which the drive shaft 48 passes. Is formed, and the lower half of the drive shaft 48 is exposed. A pad 50 which is in contact with the lower half of the drive shaft 48 is fitted into the opening 49a, and the pad 50 is pushed up by a leaf spring 51. The drive shaft 48, the slider 49 and the pad 50 are They are pressed against each other by the urging force F, and are frictionally coupled by an appropriate frictional force. Also,
It is assumed that a driven member such as a table (not shown) is connected to the slider 49.

The operation will be described. When the electrodes 41a and 42a of the piezoelectric transducer 40 are connected to the drive pulse generating circuit 54 and a sawtooth drive pulse of several tens of kHz is applied between the electrodes 41a and 42a, the piezoelectric transducer 40 undergoes an axial expansion and contraction displacement. Therefore, reciprocating vibrations having different speeds are generated in the drive shaft 48 connected to the piezoelectric transducer 40 in the axial direction. Thus, the slider 49 frictionally coupled to the drive shaft 48
Can move in the direction of slow vibration due to the asymmetry of reciprocating vibration of the drive shaft while sliding on the drive shaft 48, and can move a driven member such as a table connected to the slider.

[0062]

As described above, the piezoelectric transducer according to the first aspect of the present invention has a PZT having electrodes formed on the surface.
A thin plate-like piezoelectric element made of piezoelectric ceramics containing (PbZrO ₃ · PbTiO ₃ ) as a main component is wound around a central shaft formed by bonding a plurality of members with an adhesive that is thermally decomposed at a temperature lower than the firing temperature of the piezoelectric element. A piezoelectric conversion element characterized by having a cylindrical shape.

As the center shaft, a plurality of members are bonded with an adhesive which is thermally decomposed at a temperature lower than the firing temperature of the piezoelectric element.
More specifically, a cylindrical or cylindrical central shaft, which is composed of a plurality of disk-shaped plates separated from the displacement direction of the piezoelectric transducer, or a cylinder or cylinder, extends along the displacement direction of the piezoelectric transducer. And cut them into a plurality of segments, and glue these segments with an adhesive that decomposes at a temperature lower than the firing temperature to form a cylindrical or cylindrical central shaft. Winding work to form a tubular shape by winding around becomes easy, and not only the working efficiency is improved, but also after firing, the adhesive is thermally decomposed to form a plurality of members constituting the central shaft, that is, a plurality of plate-like members and the like. Since multiple segments are separated and the center axis can be easily removed,
A piezoelectric conversion element with good conversion efficiency can be obtained without the center shaft obstructing displacement generated in the piezoelectric conversion element.

According to a fifth aspect of the present invention, there is provided a piezoelectric transducer comprising a PZT (PbZrO ₃ .PbTi
A thin plate-shaped piezoelectric element made of a piezoelectric ceramic containing O ₃ ) as a main component is wound around a cylindrical or columnar central axis whose surface is coated with a coating agent that thermally decomposes at a temperature lower than the firing temperature. This is a piezoelectric conversion element characterized in that it is configured.

By making the surface of the piezoelectric element coated with a coating agent that decomposes at a temperature lower than the firing temperature below the firing temperature, it becomes easy to wind a thin plate-shaped piezoelectric element around the central axis to form a tubular shape. In addition to the work efficiency being improved, the coating agent thermally decomposes and evaporates after firing, so that a gap is formed between the rolled-up piezoelectric transducer and the center shaft, and the center shaft can be easily removed. In addition, a piezoelectric conversion element having good conversion efficiency can be obtained without disturbing the displacement generated in the piezoelectric conversion element by the center shaft.

The method for manufacturing a piezoelectric transducer according to the invention of claim 7 is a method for manufacturing PZT (PbZrO ₃ .P) formed in a thin plate shape.
forming electrodes on the surfaces of first and second piezoelectric elements made of piezoelectric ceramics containing (bTiO ₃ ) as a main component; forming electrodes on the first piezoelectric elements and forming no electrodes on the second piezoelectric elements; Laminating so that the surfaces face each other, bonding a plurality of members with an adhesive that is thermally decomposed at a temperature lower than the firing temperature of the piezoelectric element, winding around a central shaft to form a cylindrical body, and forming the cylindrical body A method for manufacturing a piezoelectric transducer, comprising: firing a body at a predetermined temperature; and applying a predetermined voltage between electrodes of the fired cylindrical body to polarize the body.

According to this manufacturing method, the winding operation of winding the thin plate-shaped piezoelectric element around the central axis to form a cylindrical shape is facilitated, and not only the working efficiency is improved, but also the adhesive becomes hot after firing. A plurality of members, specifically, a plurality of plate-like bodies and a plurality of segments, which disassemble and constitute the center shaft are separated, and the center shaft can be removed, so that the center shaft inhibits displacement generated in the piezoelectric transducer. Therefore, a piezoelectric conversion element having good conversion efficiency can be manufactured.

According to a twelfth aspect of the present invention, there is provided a method for manufacturing a piezoelectric transducer, wherein a PZT (PbZrO _3.
Forming electrodes on the surfaces of first and second piezoelectric elements made of piezoelectric ceramics containing PbTiO ₃ ) as a main component, and forming electrodes on the first piezoelectric element and the electrodes on the second piezoelectric element. Laminating so that the surfaces face each other, winding the cylindrical surface around a central shaft coated with a coating agent that is thermally decomposed at a firing temperature or lower to form a cylindrical body, and forming the formed cylindrical body into a predetermined shape. A method for manufacturing a piezoelectric transducer, comprising: firing at a temperature; and applying a predetermined voltage between electrodes of the fired cylindrical body to polarize the electrode.

According to this manufacturing method, the winding operation of winding a thin plate-shaped piezoelectric element around a central axis to form a cylindrical shape is facilitated, and not only the working efficiency is improved, but also the coating agent after firing is coated. Since the coating is thermally decomposed and evaporated, a gap is formed between the rolled-up piezoelectric transducer and the center shaft, the center shaft can be easily removed, and the center shaft does not hinder the displacement generated in the piezoelectric transducer. Thus, a piezoelectric conversion element having good conversion efficiency can be manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of a piezoelectric conversion element according to a first embodiment.

FIG. 2 is a cross-sectional view of the piezoelectric transducer shown in FIG.

FIG. 3 is a perspective view showing a manufacturing process of the piezoelectric transducer shown in FIG.

FIG. 4 is a perspective view showing a manufacturing process of a disc-shaped element constituting a center shaft.

FIG. 5 is a perspective view showing a manufacturing process of the center shaft.

FIG. 6 is a diagram illustrating an example of firing temperature conditions for a piezoelectric conversion element.

FIG. 7 is a diagram showing the relationship between applied voltage and displacement of a piezoelectric transducer having a normal center axis, a piezoelectric transducer having a center axis separated in a displacement direction, and a piezoelectric transducer having no center axis.

FIG. 8 is a perspective view showing a configuration of a center axis of a piezoelectric transducer according to a second embodiment.

FIG. 9 is a cross-sectional view illustrating a state where a center shaft of the piezoelectric transducer according to the second embodiment is removed.

FIG. 10 is a perspective view illustrating a configuration of a center axis of a piezoelectric transducer according to a third embodiment.

FIG. 11 is a sectional view showing an example of the configuration of an actuator using a piezoelectric transducer.

FIG. 12 is a sectional view showing a configuration of a frictional coupling portion between a slider and a drive shaft of the actuator shown in FIG. 12;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Piezoelectric conversion element 11, 12 Piezoelectric element 11a, 12a Electrode 13 Center shaft 13P Disk-shaped plate body 15 Working shaft 21 Center shaft 21a, 21b, 21c, 21d, 21e, 21f, 2
1g, 21h Segment 31 Center shaft 31a Core shaft 32 Coating agent coating 40 Piezoelectric transducer 44 Base 45, 46, 47 Support block 48 Drive shaft 49 Slider 50 Pad

Claims (13)

[Claims] 1. A PZT (PbZ) having an electrode formed on its surface.
rO_Three・ PbTiO _Three) -Based piezoelectric ceramic
A thin plate-shaped piezoelectric element made of
Composed with an adhesive that decomposes below the firing temperature of
It is characterized by being wound around the central shaft to form a cylindrical shape.
Piezoelectric transducer. 2. The piezoelectric conversion element according to claim 1, wherein the thin plate-shaped piezoelectric element is a laminate in which first and second piezoelectric elements having electrodes formed on a surface thereof are laminated. 3. The plurality of members constituting the center shaft are a plurality of disk-shaped plates separated in a direction of displacement of a piezoelectric transducer made of a high melting point material, and the center shaft is formed of a plurality of disk-shaped members. 2. The piezoelectric conversion element according to claim 1, wherein the plate is a cylindrical or cylindrical center shaft formed by laminating the plate members in the axial direction and bonding them with an adhesive that decomposes at a temperature lower than the firing temperature of the piezoelectric element. . 4. The plurality of members constituting the central shaft are a plurality of segments obtained by cutting a cylinder or a column made of a high melting point material along a displacement direction of a piezoelectric transducer, and the central shaft is formed by cutting the plurality of segments. 2. The piezoelectric transducer according to claim 1, wherein the piezoelectric transducer is a cylindrical or cylindrical center shaft formed by bonding with an adhesive that decomposes at a temperature lower than a firing temperature of the piezoelectric element. 5. A PZT (PbZ) having an electrode formed on its surface.
rO_Three・ PbTiO _Three) -Based piezoelectric ceramic
A thin plate-shaped piezoelectric element made of silicon
High melting point material coated with coating agent that decomposes below temperature
Around the center shaft made of
Piezoelectric conversion element. 6. The piezoelectric conversion element according to claim 1, wherein the center shaft is a fired center shaft formed of the same material as the thin plate-shaped piezoelectric element. 7. PZT (PbZrO) formed in a thin plate shape
Forming electrodes on the surfaces of first and second piezoelectric elements made of piezoelectric ceramics containing ( ₃ · PbTiO ₃ ) as a main component; an electrode forming surface of the first piezoelectric element and an electrode of the second piezoelectric element. Laminating such that the non-formed surfaces face each other, winding the plurality of members around a central shaft formed by bonding with an adhesive that decomposes at a temperature lower than the firing temperature of the piezoelectric element, and forming the members into a cylindrical body; A method for manufacturing a piezoelectric transducer, comprising: firing a cylindrical body at a predetermined temperature; and applying a predetermined voltage between electrodes of the fired cylindrical body to polarize the cylindrical body. 8. The method for manufacturing a piezoelectric transducer, further comprising:
Forming a plurality of disk-shaped plates separated from the displacement direction of the piezoelectric conversion element made of a high melting point material as a plurality of members, and laminating the disk-shaped plates in the axial direction to form a piezoelectric element 8. The method of manufacturing a piezoelectric transducer according to claim 7, further comprising a center shaft forming step of forming a cylindrical or columnar shape by bonding with an adhesive that is thermally decomposed at a firing temperature or lower. 9. The method for manufacturing a piezoelectric transducer according to claim 9, further comprising:
9. The method according to claim 8, further comprising a step of removing the center axis after firing at a predetermined temperature. 10. The method of manufacturing a piezoelectric transducer, further comprising cutting a cylinder or a cylinder made of a high melting point material as a plurality of members along a displacement direction of the piezoelectric transducer to form a plurality of segments. 8. The method according to claim 7, further comprising the step of forming a center shaft for forming the cylinder into a cylindrical shape or a cylindrical shape by bonding the segments with an adhesive that decomposes at a temperature lower than the firing temperature of the piezoelectric element.
A manufacturing method of the piezoelectric conversion element according to the above. 11. The method according to claim 10, further comprising the step of removing the center axis after firing at a predetermined temperature. 12. PZT (PbZr) formed in a thin plate shape
Forming electrodes on the surfaces of first and second piezoelectric elements made of piezoelectric ceramics whose main component is O ₃ .PbTiO ₃ ); and forming an electrode on the first piezoelectric element and an electrode forming surface of the second piezoelectric element. Laminating so that the non-electrode-formed surfaces face each other, winding the surface around a central shaft coated with a coating agent that is thermally decomposed at a temperature lower than the firing temperature of the piezoelectric element to form a cylindrical body, and forming the cylindrical body. A method for manufacturing a piezoelectric transducer, comprising: firing a body at a predetermined temperature; and applying a predetermined voltage between electrodes of the fired cylindrical body to polarize the body. 13. The method according to claim 12, further comprising the step of removing the center axis after firing at a predetermined temperature.