JP2001037262A - Piezoelectric transducer and actuator using piezoelectric transducer - Google Patents

Abstract

(57) [Problem] To provide a piezoelectric conversion element having a high drive efficiency and an actuator using the piezoelectric conversion element by eliminating the work of connecting a lead wire to an electrode of the piezoelectric conversion element. SOLUTION: A first electrode 11a and a second electrode 12a are formed on the surface of two thin plate-shaped piezoelectric elements 11 and 12, respectively, and the back surface is an electrode non-formed surface. Piezoelectric element 1
The electrode-free surface of the piezoelectric element 12 and the electrode-forming surface of the piezoelectric element 12 face each other and overlap each other to form a cylindrical body. The first end face of the cylindrical body
An electrode is not formed near the ends of the first electrode 11a and the second electrode 12a so that the electrode is exposed and the second electrode is not exposed, and so that the second electrode is exposed on the second end surface and the first electrode is not exposed. These are ends 11b and 12b. Since the electrode 11a is exposed at the first end face of the cylindrical body and the electrode 12a is exposed at the second end face, the conductive support block and the coupling member of the actuator for fixing the end face of the piezoelectric transducer are connected to the first electrode 11a and the second electrode. It can be used as a terminal of the electrode 12a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric transducer, and more particularly to an electrode structure of a piezoelectric transducer in which a sheet-like piezoelectric material is formed in a cylindrical shape, and an actuator using the piezoelectric transducer.

[0002]

2. Description of the Related Art An actuator using a piezoelectric conversion element has a high conversion efficiency for converting supplied electric energy into driving force, is small in size and light in weight, generates a large driving force, and easily controls the driving force. As a result, they have been used for driving and positioning components of cameras, measuring instruments, and other precision machines.

Some of the piezoelectric transducers, which are driving sources used in such actuators, include a plurality of unitary piezoelectric elements 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.

[0005] For this reason, there has been proposed a piezoelectric conversion element formed by winding a laminate in which two thin plate-shaped piezoelectric elements each having electrodes formed on the surface thereof are stacked in a hollow cylindrical shape.

FIG. 12 is a perspective view showing an example of a cylindrical piezoelectric transducer formed by laminating two thin plate-like piezoelectric elements, and FIGS. 13 (a) and 13 (b) show the same. FIG. 14 is a plan view for explaining a state of an end face in a cylindrical axis direction of a cylindrical piezoelectric conversion element.

The manufacturing process of the piezoelectric transducer will be described. First, as shown in FIG. 13A, a first piezoelectric element 101 and a second piezoelectric element 102 made of a piezoelectric ceramic formed in a thin plate shape are prepared. Here, the length in the winding direction of the second piezoelectric element 102 is set to the first piezoelectric element 101.
Longer than the dimension d.

A first electrode 103 is formed on the front surface of the first piezoelectric element 101, and the back surface is a surface on which no electrode is formed. Further, the second electrode 104 is formed on the front surface of the second piezoelectric element 102, and the back surface is a surface on which no electrode is formed (see FIG. 13A).

Next, as shown in FIG.
Of the piezoelectric element 101 on which the electrode is not formed and the second piezoelectric element 10
Lamination is performed so that the two electrode forming surfaces face each other, and the laminated body is wound up into a cylindrical body to form a shape as shown in FIG.
By making the length of the second piezoelectric element 102 in the winding direction longer than the length of the first piezoelectric element 101 in the winding direction, the first electrode 103 and the second electrode 1 can be formed in a cylindrical shape.
04 are displaced and lead wires 10 are easily connected to those electrodes.
3a and 104a can be connected.

[0010]

As shown in FIG. 14, in the cylindrical piezoelectric transducer having the above-described structure, the first electrode 103 of the first piezoelectric element 101 and the first electrode 103 of the first piezoelectric element 101 are provided on the end face in the cylindrical axial direction. The end face of the second electrode 104 of the second piezoelectric element 102 is exposed. For this reason, if the cylindrical axial end face of the piezoelectric transducer is joined to a conductive mechanism member such as an actuator support block, the first electrode 103 and the second electrode 104 are short-circuited.

Conventionally, in order to prevent this short circuit, an epoxy resin-based adhesive is applied to the end face of the piezoelectric conversion element in the cylindrical axis direction to form an insulating film, or the end face of the piezoelectric conversion element in the cylindrical axis direction is conventionally used. Although an insulating thin plate made of alumina or the like was sandwiched between the conductive member and the conductive mechanism member, the flatness of the cylindrical axial end face of the piezoelectric transducer could not be ensured, There is an inconvenience that the coating acts as a damper and the displacement generated in the piezoelectric transducer cannot be transmitted to the mechanism member without waste.

Connecting the lead wires to the first and second electrodes exposed on the side surface of the cylindrical piezoelectric conversion element as shown in FIGS. Since the thickness is about 40 μm and extremely thin, it is difficult to work with great care and it is difficult to connect lead wires with stable strength. An object of the present invention is to solve the above problems.

[0013]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. According to a first aspect of the present invention, a thin plate-shaped first piezoelectric element on which a first electrode is formed and a second electrode are formed. In a piezoelectric transducer formed by laminating a thin plate-shaped second piezoelectric element into a cylindrical body, at least the first electrode or the second electrode is provided on an end surface of the cylindrical body in a cylindrical axial direction. The electrode is exposed.

According to a second aspect of the present invention, there is provided a laminate comprising a thin plate-shaped first piezoelectric element having a first electrode formed thereon and a thin plate-shaped second piezoelectric element having a second electrode formed thereon. Is formed in a cylindrical body, a first electrode is exposed on a first end surface of the cylindrical body in a cylindrical axial direction, and the second electrode is formed on a second end surface different from the first end surface. The electrode is exposed.

The first electrode has a shape that is exposed only at a first end face of the cylindrical body in the direction of the cylindrical axis, and the second electrode has a shape of the first end face of the cylindrical body in the direction of the cylindrical axis. It is good to make it the shape exposed only to the 2nd end surface different from.

According to a fourth aspect of the present invention, there is provided a laminate comprising a thin plate-shaped first piezoelectric element having a first electrode formed thereon and a thin plate-shaped second piezoelectric element having a second electrode formed thereon. Is formed in a cylindrical body, a first electrode is exposed on a part of a first axial end face of the cylindrical body in a cylindrical axial direction, and the first electrode on the first end face is exposed. The second electrode is exposed in a portion different from the portion where the second electrode is provided.

The first electrode has a shape that is exposed on a part of a first end surface of the cylindrical body in a cylindrical axial direction, and the second electrode has
The electrode may be formed in a shape that is exposed at a portion different from the portion where the first electrode is exposed in the cylindrical axis direction of the cylindrical body.

According to a sixth aspect of the present invention, there is provided a laminate comprising a thin plate-shaped first piezoelectric element having a first electrode formed thereon and a thin plate-shaped second piezoelectric element having a second electrode formed thereon. Are formed in a cylindrical body, and two piezoelectric conversion elements having first and second electrodes exposed on the end surfaces thereof; a coupling member for mutually coupling the end surfaces of the two piezoelectric conversion elements; A driven member frictionally coupled to the member, and driving the driven member by generating an elliptical vibration in the coupling member by applying an alternating voltage having a different phase between the electrodes of the two piezoelectric conversion elements. An actuator using a piezoelectric conversion element characterized by the following.

According to a seventh aspect of the present invention, there is provided a laminate comprising a thin plate-shaped first piezoelectric element having a first electrode formed thereon and a thin plate-shaped second piezoelectric element having a second electrode formed thereon. Is formed in a cylindrical body, and a piezoelectric conversion element in which an electrode is exposed on one end face of the cylindrical body in a cylindrical axial direction, and one end face of the piezoelectric conversion element is supported and as an electrode terminal of the piezoelectric conversion element. A functional supporting member, a driving member coupled to an end surface of the piezoelectric transducer, and a driven member frictionally coupled to the driving member, wherein a driving pulse is supplied to an electrode of the piezoelectric transducer via the supporting member. An actuator using a piezoelectric conversion element, wherein reciprocating vibrations having different speeds are generated in a driving member coupled to the piezoelectric conversion element to move a driven member frictionally coupled to the driving member in a predetermined direction.

[0020]

Embodiments of the present invention will be described below.

[First Embodiment] The piezoelectric conversion element of the first embodiment is a piezoelectric conversion element formed by laminating two thin plate-like piezoelectric elements into a cylindrical body. 1 and 2
FIGS. 1A and 1B are diagrams illustrating a configuration of a piezoelectric conversion element according to a first embodiment. FIGS. 1A and 1B illustrate shapes of electrodes formed on surfaces of two thin plate-shaped piezoelectric elements. 2 (a) and 2 (b) show a state of a left end face and a right end face in a cylindrical axial direction of a piezoelectric element formed by laminating the two thin plate-shaped piezoelectric elements into a cylindrical body. FIG. 3 is a perspective view showing the appearance of a piezoelectric transducer formed in a cylindrical body.

An outline of the structure of the piezoelectric conversion element will be described. As shown in FIGS. 1A and 1B, the first piezoelectric element 1
The first electrode 11a is formed on the front surface of No. 1 and the back surface is an electrode non-formed surface. When the first electrode 11a is formed, the first end surface in the cylindrical axial direction of the cylindrical body when the piezoelectric elements are laminated to form the cylindrical body, that is, one end surface (the lower end in FIG. 1A). The vicinity of the end face) is the electrode non-forming end 11b.

A second electrode 1 is provided on the surface of the second piezoelectric element 12.
2a is formed, and the back surface is an electrode non-formation surface. Second electrode 1
When forming 2a, the second end face in the cylindrical axis direction of the cylindrical body when the piezoelectric elements are laminated to form a cylindrical body, that is, an end face different from the first end face (in FIG. 1B, The portion near the upper end surface) is the electrode non-forming end portion 12b.

Next, the electrode-free surface of the first piezoelectric element 11 and the electrode-formed surface of the second piezoelectric element 12 are opposed to each other and overlapped to form a laminate. At this time, the non-electrode forming end 11b of the first electrode 11a of the first piezoelectric element 11 and the non-electrode forming end 12b of the second electrode 12a of the second piezoelectric element 12
When the laminated piezoelectric elements 11 and 12 are formed in a cylindrical shape,
The layers are laminated so as to be located at positions opposite to each other in the cylindrical axial direction.

The laminated piezoelectric elements 11 and 12 are formed in a cylindrical body, the cylindrical body is fired at a predetermined temperature, and a voltage is applied between the electrodes to polarize the piezoelectric element, thereby completing the piezoelectric conversion element.

Next, details of the manufacturing process will be described. First, as a material of the piezoelectric elements 11 and 12, PZT (P
Piezoelectric ceramics whose main component is bZrO 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 on a uniform plane using a blade or the like to have a uniform thickness, for example, 20 to 10
Stretch to a thickness of 0 μm. When the solvent is evaporated and dried, a flexible sheet called a green sheet can be obtained.

Next, on the surface of the green sheet (piezoelectric element), paste-like electrode material, for example, platinum (Pt), silver-palladium (Ag-
An electrode material obtained by converting a Pd) -based electrode material into a paste with an appropriate resin binder is printed to a thickness of 3 to 7 μm (after firing, the resin binder volatilizes to about 1 to 3 μm). 11a and the second electrode 12a are formed.

The piezoelectric element on which the electrodes are formed by printing is cut into a predetermined size, and the non-electrode-formed surface of the first piezoelectric element 11 and the electrode-formed surface of the second piezoelectric element 12 are overlapped so as to face each other. A laminate is formed, and the laminate is formed into a cylindrical body.

As shown in FIGS. 2A and 2B and FIG. 3, the non-electrode-forming end 11b of the first electrode 11a of the first piezoelectric element 11 and the second electrode Two electrodes 1
The electrode-free end portion 12b of the piezoelectric element 2a
When 1 and 12 are formed in a cylindrical shape, they are stacked so as to be located at positions opposite to each other in the cylindrical axial direction. Therefore, when formed in a cylindrical shape, the first end face (one end face) has a first end face. Only the end face of the first electrode 11a of the piezoelectric element 11 is exposed,
Only the end face of the second electrode 12a of the second piezoelectric element 12 is exposed on the end face (an end face different from the first end face), and even if it is joined to a conductive mechanism member such as a drive shaft of an actuator. There is no possibility that the first electrode 11a and the second electrode 12a are short-circuited.

Next, the cylindrical body is fired under a predetermined temperature condition, and a lead wire is connected to the first electrode 11a and the second electrode 12a, and a predetermined high DC voltage is applied to cause polarization. The device 10 is completed.

As shown in FIG. 4, for example, as shown in FIG. 4, the temperature is gradually raised to 500 ° C. in about 5 hours, and after debinding for 500 hours at 500 ° C., the temperature is raised to 1200 ° C. 9 hours after the beginning. Gradually increase the temperature. Further, after baking at 1200 ° 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-like piezoelectric element. For example, in an environment of 60 ° C., 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 of the piezoelectric elements 11 and 12 in the direction of the cylindrical axis can be generated.

Next, the structure of an actuator using the above-described piezoelectric transducer will be described with reference to FIG. In FIG. 5, reference numerals 21 and 22 denote support blocks made of a conductive material, and the support blocks 21 and 22 are connected by a connecting member 23 made of an electrically insulating material.

The first end faces of the cylindrical piezoelectric elements 27 and 28 are fixed to the inclined surfaces 21a and 22a of the support blocks 21 and 22, respectively.
And 28 are connected by a connecting member 24 made of a conductive material. A driven member 25 is frictionally coupled on the coupling member 24.

Since the piezoelectric conversion elements 27 and 28 have the same configuration as the piezoelectric conversion element 10 described above, if the first end face of the piezoelectric conversion element 27 is fixed to the support block 21, the piezoelectric conversion element 27 The first electrode 11a is electrically connected to the support block 21, and when the first end face of the piezoelectric transducer 28 is fixed to the support block 22, the first electrode 11a of the piezoelectric transducer 28 is electrically connected to the support block 22. Is done.

That is, the support blocks 21 and 22 also function as terminals of the first electrodes 11a of the piezoelectric transducers 27 and 28, respectively.

Further, the second of the piezoelectric transducers 27 and 28
When the end face is coupled to the coupling member 24 made of a conductive material, the second electrode 12a of the piezoelectric transducer 27 is connected to the coupling member 2
4 and the second piezoelectric conversion element 28
When the end face is coupled to the coupling member 24, the second electrode 12a of the piezoelectric transducer 28 is electrically connected to the coupling member 24.
That is, the coupling member 24 is the second member of the piezoelectric transducers 27 and 28.
It also functions as a common terminal of the electrode 12a.

As described above, the support block 2
1, 22, and the coupling member 24 function as the terminals of the first electrode 11a and the second electrode 12a of the piezoelectric transducers 27 and 28, so that the operation of connecting the lead wires to the first electrode 11a and the second electrode 12a is performed. Can be omitted.

In the above configuration, the first electrode 1 of the piezoelectric transducer 27 is supported via the support block 21 and the coupling member 24.
A sine wave voltage is applied between the first electrode 11a (+ pole) and the first electrode 11a (+ pole) of the piezoelectric transducer 28 via the support block 22 and the coupling member 24. When a sine wave voltage having a different phase from that of the first electrode 12a (−pole) is applied between the two electrodes 12a (−pole), an elliptical vibration is generated in the coupling member 24, and the driven member 25 frictionally coupled to the coupling member 24 can be driven. .

FIG. 6 shows a modification of the piezoelectric transducer of the first embodiment in which the shape of the electrodes formed on the surface of the piezoelectric element is partially changed.

As shown in FIGS. 6A and 6B, a first electrode 31a is formed on the surface of the first piezoelectric element 31.
The back surface is an electrode non-formed surface. When forming the first electrode 31a, the first end face in the cylindrical axis direction of the cylindrical body when the piezoelectric elements are laminated to form the cylindrical body, that is, one end face (the lower end in FIG. 6A). The end face (near the end face) and the second end face in the cylindrical axial direction, that is, an end face different from the first end face (near the upper end face in FIG. 6A) are the electrode non-formation ends 31b and 31c.

The second electrode 3 is provided on the surface of the second piezoelectric element 32.
2a is formed, and the back surface is an electrode non-formation surface. Second electrode 3
When forming 2a, the second end surface in the cylindrical axial direction of the cylindrical body when the piezoelectric elements are laminated to form a cylindrical body, that is, an end surface different from the first end surface (in FIG. 6B, The vicinity of the upper end surface) is an electrode non-forming end portion 32b.

Next, the electrode-free surface of the first piezoelectric element 31 and the electrode-formed surface of the second piezoelectric element 32 face each other and overlap each other to form a laminate.

The laminated piezoelectric elements 31 and 32 are formed in a cylindrical body, the cylindrical body is fired at a predetermined temperature, and a voltage is applied between the electrodes to polarize the piezoelectric element 31. Thus, the piezoelectric conversion element 30 is completed. The details of the manufacturing process are the same as those of the piezoelectric conversion element according to the first embodiment, and a description thereof will be omitted.

According to the above configuration, the stacked piezoelectric elements 3
When 1 and 32 are formed in a cylindrical body, only the end face of the second electrode 32a of the second piezoelectric element 32 is exposed on the first end face (one end face), and the second end face (the first end face and the second end face) is formed. The first electrode 31a of the first piezoelectric element 31 is
The second electrode 32a of the piezoelectric element 32 is not exposed.

Accordingly, the first end face of the piezoelectric transducer where the second electrode 32a is exposed at the end face is fixed to a support block of the actuator, and the second end face is joined to a conductive mechanism member such as a drive shaft of the actuator. In this case, the drive voltage may be applied to the piezoelectric conversion element by applying the drive voltage between the support block and the first electrode 31a exposed on the side surface of the first piezoelectric element 31.

Next, the configuration of a linear drive type actuator using the above-described piezoelectric transducer 30 will be described with reference to FIG.

In FIG. 7, reference numeral 33 denotes a frame;
5 and 36 are support blocks, 37 is a drive shaft, and a drive shaft 37 is provided.
Is supported movably in the axial direction by a support block 35 and a support block 36. The first end face of the piezoelectric conversion element 30 is bonded and fixed to the support block 34 with a conductive adhesive or the like, and the second end face is bonded and fixed to one end of the drive shaft 37. The drive shaft 37 can be displaced in the axial direction (the direction of the arrow a and the direction opposite thereto) by the displacement of the piezoelectric conversion element 30 in the cylindrical axial direction.

Numeral 38 denotes a slider block, through which a drive shaft 37 extends in the lateral direction. An opening is formed in a lower portion of the slider block 38 through which the drive shaft 37 passes, and a lower half of the drive shaft 37 is exposed.
A pad 38a which is in contact with the lower half of 7 is inserted.
A projection 38b is formed at a lower portion of the pad 38a, and the projection 38b is pushed up by a leaf spring 38c. With this configuration, the pad 38a is provided with an upward biasing force F that comes into contact with the drive shaft 37. Reference numeral 39 denotes a table on which articles are placed.
9a.

With the above structure, the slider block 38 including the pad 38a and the drive shaft 37 are pressed against each other by the urging force F of the leaf spring 38c and are frictionally connected.

Next, the operation will be described. First, the first end face of the piezoelectric conversion element 30 is bonded and fixed to the support block 34 with a conductive adhesive or the like, and the support block 34 also functions as a terminal of the second electrode 32a of the piezoelectric conversion element 30. 34 and the first electrode 3 of the piezoelectric transducer 30
1a is applied to the first electrode 31.
A drive voltage will be applied between the first electrode 32a and the second electrode 32a.

When a saw-tooth wave driving pulse having a gentle rising portion and a rapid falling portion is applied between the first electrode 31a and the second electrode 32a, the piezoelectric conversion element 30 is formed at the gentle rising portion of the driving pulse. And the drive shaft 37 coupled to the piezoelectric transducer 30 is also gently displaced in the direction of arrow a. At this time, the slider block 38 frictionally coupled to the drive shaft 37 moves together with the drive shaft 37 in the direction of arrow a due to the frictional coupling force.

Next, in the rapid falling portion of the drive pulse, a rapid contraction displacement occurs in the piezoelectric conversion element 30, and the drive shaft 37 connected to the piezoelectric conversion element 30 is also rapidly displaced in the direction opposite to the arrow a. At this time, the slider block 38 frictionally coupled to the drive shaft 37 substantially overcomes the frictional coupling force due to the inertial force and stays at that position, and does not move.

By continuously applying drive pulses to the piezoelectric transducer 30 to generate reciprocating vibrations having different speeds, the slider block 38 and the table 39 fixed to the slider block 38 are continuously moved in the direction of arrow a. Can be moved.

To move the slider block 38 and the table 39 in the opposite direction (the direction opposite to the arrow a),
This can be achieved by changing the waveform of the saw-tooth wave drive pulse applied to the piezoelectric conversion element 30 and applying a saw-tooth wave drive pulse having a rapid rising portion and a gentle falling portion.

The term "substantially" as used herein means that the slider block 38 and the friction coupling surface between the pad 38a and the drive shaft 37 slide in the direction of the arrow a and in the direction opposite thereto while sliding. However, there is also included one that moves in the direction of arrow a as a whole due to the difference in driving time.

[Second Embodiment] The piezoelectric conversion element of the second embodiment is also a piezoelectric conversion element in which two thin plate-shaped piezoelectric elements are laminated to form a cylindrical body. In the piezoelectric conversion element according to the embodiment, the first electrode and the second electrode are configured to be exposed at one end face of the cylindrical body in the direction of the cylindrical axis.

FIGS. 8 and 9 are views for explaining the structure of the piezoelectric transducer according to the second embodiment. FIGS. 8A and 8B show the surface of two thin piezoelectric elements. FIGS. 9A and 9B show the shape of the electrode formed in FIG.
It is a side view explaining the state of the left end face and the right end face in the cylindrical axis direction of the piezoelectric conversion element formed by laminating two thin plate-shaped piezoelectric elements into a cylindrical body.

An outline of the structure of the piezoelectric conversion element will be described. As shown in FIGS. 8A and 8B, the first piezoelectric element 4
The first electrode 41a is formed on the front surface of No. 1, and the back surface is an electrode non-formed surface. When the piezoelectric elements are laminated and formed into a cylinder,
An end surface in the cylindrical axial direction (near the upper and lower end surfaces of substantially the right half in FIG. 8A) of the element wound near the center of the cylindrical body is an electrode non-formed end portion 41b.

The second electrode 4 is provided on the surface of the second piezoelectric element 42.
2a is formed, and the back surface is an electrode non-formation surface. When the piezoelectric elements are laminated and formed into a cylindrical shape, the end surface in the cylindrical axial direction of the element wound in the side far from the center of the cylindrical body (near the upper and lower end surfaces in the substantially left half in FIG. 8B). It is referred to as an electrode non-forming end 42b.

Next, the electrode-free surface of the first piezoelectric element 41 and the electrode-formed surface of the second piezoelectric element 42 are overlapped so as to face each other to form a laminate.

The laminated piezoelectric elements 41 and 42 are formed in a cylindrical shape, the formed cylindrical body is fired at a predetermined temperature, and a voltage is applied between the electrodes to be polarized, whereby the piezoelectric conversion element 40 is completed.

The material of the piezoelectric elements 41 and 42 is PZT (PbZrO ₃ .PbTi) as in the first embodiment.
Piezoelectric ceramics whose main component is O ₃ ) are used. The electrode material, the method for forming the electrodes, the temperature conditions for baking, the polarization treatment, and the like are the same as those in the first embodiment, and a description thereof will not be repeated.

As shown in FIGS. 9A and 9B, when the laminated piezoelectric elements 41 and 42 are formed in a cylindrical shape, the first piezoelectric element 41 of the first piezoelectric element 41 is provided on both end surfaces of the cylindrical body. Electrode 41a
Is exposed on the side closer to the outside of the end face of the tubular body, and the end face of the second electrode 42a of the second piezoelectric element 42 is exposed on the side closer to the inside of the end face of the tubular body.

In order to supply power to the first electrode 41a and the second electrode 42a of the piezoelectric transducer 40, a terminal plate 45 having the shape shown in FIG. 10 is used. That is, as shown in FIG. 10, the terminal plate 45 joined to the end face of the piezoelectric transducer 40 has terminals 45a and 45b provided radially from the center on the surface of a plate made of an electrically insulating material. Things.

Here, the terminal 45a is arranged at a position distant from the center thereof, and the first electrode 4 of the piezoelectric element 41 is connected to the terminal 45a.
1a is electrically connected.

The terminal 45b is arranged at a position near the center thereof, and the second electrode 42a of the piezoelectric element 42 is electrically connected to the terminal 45b. The terminal 45b may further extend through the back surface of the terminal plate 45, and a connection terminal 45c for a lead wire may be provided at an end of the terminal plate 45.

The piezoelectric transducer 40 having the above-described structure can be used as a drive element for an actuator, as in the first embodiment.

[Third Embodiment] The piezoelectric conversion element of the third embodiment is also a piezoelectric conversion element formed by laminating two thin plate-like piezoelectric elements to form a cylindrical body. The piezoelectric conversion element according to the embodiment is configured such that the first electrode and the second electrode are exposed at one end face of the cylindrical body in the cylindrical axial direction, and the piezoelectric conversion element in the cylindrical axial direction of the cylindrical body. The other end face is configured so that the first and second electrodes are not exposed.

FIG. 11 is a view showing the shapes of electrodes formed on the surfaces of two thin plate-like piezoelectric elements constituting the piezoelectric conversion element according to the third embodiment.

An outline of the structure of the piezoelectric transducer will be described. As shown in FIGS. 11A and 11B, a first electrode 51a is formed on the surface of the first piezoelectric element 51, and the back surface is a non-electrode-formed surface. When the piezoelectric elements are stacked and formed into a cylindrical shape, the first end face in the cylindrical axial direction of the element wound around the center of the cylindrical body (near the lower end face near the right half in FIG. 11A). ) Is the electrode non-formed end portion 51b.
The end face (near the upper end face in FIG. 11A) is also the electrode non-formed end 51c.

The second electrode 5 is provided on the surface of the second piezoelectric element 52.
2a is formed, and the back surface is an electrode non-formation surface. At this time,
When the piezoelectric elements are laminated and formed into a cylindrical shape, the first element in the cylindrical axial direction of the element that is wound farther from the center of the cylindrical body.
The end face (near the lower half of the left half in FIG. 11B) is an electrode non-forming end 52b, and the second end face (near the upper end in FIG. 11B) is the electrode non-forming end 52c. And

Next, the electrode-free surface of the first piezoelectric element 51 and the electrode-formed surface of the second piezoelectric element 52 are opposed to each other and overlapped to form a laminate.

The laminated piezoelectric elements 51 and 52 are formed in a cylindrical shape, the formed cylindrical body is fired at a predetermined temperature, and a voltage is applied between the electrodes to polarize the piezoelectric elements, thereby completing the piezoelectric conversion element.

The materials of the piezoelectric elements 51 and 52 are PZT (PbZrO ₃ .PbTi) as in the first embodiment.
Piezoelectric ceramics whose main component is O ₃ ) are used. The electrode material, the method for forming the electrodes, the temperature conditions for baking, the polarization treatment, and the like are the same as those in the first embodiment, and a description thereof will not be repeated.

When the laminated piezoelectric elements 51 and 52 are formed in a cylindrical shape, the first electrode 5 of the first piezoelectric element 51 is provided on the first end face of the cylindrical body in the same manner as the piezoelectric conversion element of the second embodiment.
The end face of 1a is exposed on the side near the outside of the end face of the cylindrical body, and the end face of the second electrode 52a of the second piezoelectric element 52 is exposed on the side near the inside of the end face of the cylindrical body. The first electrode 51a and the second electrode 52a are not exposed on one end surface (second end surface) of the tubular body.

In order to supply power to the first electrode 51a and the second electrode 52a of the piezoelectric transducer 50, the terminal plate 45 having the shape shown in FIG. Should be used.

The piezoelectric transducer 50 having the above-described structure can be used as a drive element of an actuator, as in the first embodiment.

[0079]

As described above, in the piezoelectric transducer according to the present invention, the electrode is exposed at the end face in the cylindrical axial direction, and the supporting member or the connecting member to which the end face of the piezoelectric transducer is joined is positively operated. In this case, an insulating coating made of epoxy resin adhesive is formed on the end surface in the cylindrical axial direction like a conventional piezoelectric transducer, or an insulating thin plate such as alumina is used. The flatness of the end surface of the piezoelectric element in the cylindrical axis direction can be easily secured because no piezoelectric element is sandwiched between the piezoelectric elements. Can be transmitted to the member.

Further, it is possible to omit all or a part of the difficult work of connecting the lead wires to the electrodes of the piezoelectric element constituting the piezoelectric transducer, and to connect the lead wires to the electrodes with stable strength. It has a great effect.

In the actuator using the piezoelectric transducer according to the present invention, since the electrodes are exposed at the end face in the cylindrical axis direction of the piezoelectric transducer, the piezoelectric element is supported via the member supporting the end face of the piezoelectric transducer. A drive voltage or a drive pulse can be supplied to the conversion element, and the configuration of the actuator can be easily summarized.

[Brief description of the drawings]

FIG. 1 shows a configuration 2 of a piezoelectric conversion element according to a first embodiment.
The figure explaining the shape of the surface electrode of one piezoelectric element.

FIG. 2 is a side view for explaining left and right end faces of the piezoelectric transducer shown in FIG. 1 in a cylindrical axial direction.

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

FIG. 4 is a diagram showing an example of firing temperature conditions for a piezoelectric conversion element.

FIG. 5 is a sectional view showing an example of the configuration of an actuator using a piezoelectric transducer.

FIG. 6 illustrates a second embodiment of the piezoelectric transducer according to the first embodiment.
The figure explaining the modification of the surface electrode shape of one piezoelectric element.

FIG. 7 is a cross-sectional view showing another example of the configuration of the actuator using the piezoelectric transducer.

FIG. 8 shows a second embodiment of the piezoelectric transducer according to the second embodiment.
The figure explaining the shape of the surface electrode of one piezoelectric element.

9 is a side view for explaining the left and right end surfaces of the piezoelectric transducer shown in FIG. 6 in the cylindrical axial direction.

FIG. 10 is a plan view illustrating a configuration of a terminal plate of the piezoelectric transducer shown in FIG.

FIG. 11 is a view for explaining shapes of surface electrodes of two piezoelectric elements constituting the piezoelectric conversion element according to the third embodiment.

FIG. 12 is a perspective view showing an example of a conventional piezoelectric conversion element formed by laminating two thin plate-shaped piezoelectric elements into a cylindrical shape.

FIG. 13 is a view for explaining an electrode forming surface and a laminated state of the conventional piezoelectric conversion element shown in FIG.

FIG. 14 is a plan view illustrating an end face of the conventional piezoelectric transducer shown in FIG. 10 in a cylindrical axis direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Piezoelectric conversion element 11 1st piezoelectric element 11a 1st electrode 11b Electrode-free end 12 Second piezoelectric element 12a Second electrode 12b Electrode-free end 21, 22 Support block 23 Coupling member 24 Coupling member 25 Driven Member 27, 28 Piezoelectric conversion element 30 Piezoelectric conversion element 31 First piezoelectric element 31a First electrode 31b, 31c Non-electrode forming end 32 Second piezoelectric element 32a Second electrode 32b Non-electrode forming end 33 Frame 34, 35 , 36 support block 37 drive shaft 38 slider block 38a pad 39 table 40 piezoelectric conversion element 41 first piezoelectric element 41a first electrode 41b electrode-free end 42 second piezoelectric element 42a second electrode 42b electrode-free end 45 terminal plate 51 first piezoelectric element 51a first electrode 51b, 51c electrode non-forming end 52 Second piezoelectric element 52a Second electrode 52b, 52c Non-electrode-formed end

Claims (7)

[Claims] 1. A laminated body formed by laminating a thin plate-shaped first piezoelectric element having a first electrode formed thereon and a thin plate-shaped second piezoelectric element having a second electrode formed thereon is formed into a cylindrical body. In the formed piezoelectric conversion element, at least the first electrode or the second electrode is exposed at first and second end surfaces of the cylindrical body in a cylindrical axis direction. 2. A cylindrical body is formed by laminating a thin plate-shaped first piezoelectric element having a first electrode formed thereon and a thin plate-shaped second piezoelectric element having a second electrode formed thereon. In the formed piezoelectric transducer, a first electrode is exposed on a first end face of the cylindrical body in a cylindrical axial direction, and a second electrode is provided on a second end face different from the first end face.
A piezoelectric transducer having electrodes exposed. 3. The first electrode has a shape that is exposed only at a first end surface of the cylindrical body in a cylindrical axial direction, and the second electrode is formed on the first end surface of the cylindrical body in a cylindrical axial direction. 3. The piezoelectric conversion element according to claim 2, wherein the piezoelectric conversion element has a shape exposed only to a second end face different from the second end face. 4. A laminate formed by laminating a thin plate-shaped first piezoelectric element on which a first electrode is formed and a thin plate-shaped second piezoelectric element on which a second electrode is formed is formed into a cylindrical body. In the formed piezoelectric conversion element, a portion where a first electrode is exposed on a part of a first end surface in a cylindrical axis direction of the cylindrical body, and a portion where the first electrode is exposed on the first end surface is A piezoelectric transducer, wherein the second electrode is exposed at a different portion. 5. The first electrode has a shape that is exposed on a part of a first end surface of the cylindrical body in a cylindrical axial direction, and the second electrode is formed of the first electrode in a cylindrical axial direction of the cylindrical body. 5. The piezoelectric conversion element according to claim 4, wherein the piezoelectric conversion element has a shape that is exposed at a portion different from a portion where the electrode is exposed. 6. A laminated body formed by laminating a thin plate-shaped first piezoelectric element having a first electrode formed thereon and a thin plate-shaped second piezoelectric element having a second electrode formed therein is formed into a cylindrical body. Two piezoelectric transducers formed and having electrodes exposed on the end faces of the cylindrical body, a coupling member for mutually coupling the end faces of the two piezoelectric transducers, and a driven member frictionally coupled to the coupling member A piezoelectric member, wherein an elliptical vibration is generated in the coupling member by applying an AC voltage having a different phase between the electrodes of the two piezoelectric conversion elements, and the driven member is driven. Actuator using. 7. A laminate formed by laminating a thin plate-shaped first piezoelectric element on which a first electrode is formed and a thin plate-shaped second piezoelectric element on which a second electrode is formed is formed into a cylindrical body. A piezoelectric conversion element formed and exposing an electrode to one end face of the cylindrical body in the cylindrical axis direction; and a support member that supports one end face of the piezoelectric conversion element and functions as an electrode terminal of the piezoelectric conversion element. A driving member coupled to an end face of the piezoelectric conversion element, and a driven member frictionally coupled to the driving member, wherein a driving pulse is supplied to an electrode of the piezoelectric conversion element via the support member, and the driving pulse is supplied to the piezoelectric conversion element. An actuator using a piezoelectric transducer, wherein reciprocating vibrations having different speeds are generated in a driving member to be coupled and a driven member frictionally coupled to the driving member is moved in a predetermined direction.