JPH09191135A - Laminated piezoelectric actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase speed of response and attain bending displacement by stacking a plurality of piezoelectric ceramic layers on one side and the other side of a core material, and making the core material an unpolarized piezoelectric inactivated layer. SOLUTION: The piezoelectric actuator 20 is of laminated type, and formed by stacking a plurality of piezoelectric ceramic layers 2,... on one side of a core material 32, and stacking a plurality of piezoelectric ceramic layers 2,... also on the other side of the core material 32. The core material 32 is made an unpolarized piezoelectric inactivated layer. The piezoelectric substance composing the piezoelectric ceramic layers 2 is a solid solution, designated as PZT, of lead zirconate and lead titanate, lead titanate or the like. The core material 32 uses the same material as the piezoelectric substance composing the piezoelectric ceramic layers 2. The same material is used both for the core material 32 and the piezoelectric ceramic layers 2, and their coefficients of thermal expansion are thereby matched with each other to prevent their separation in the boundary between them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated piezoelectric actuator capable of bending displacement, and particularly, for a textile machine,
In particular, the present invention relates to a piezoelectric actuator that can be suitably used in a warp control device for a weaving machine and a needle selecting device for a sock knitting machine.

[0002]

2. Description of the Related Art Conventionally, lead zirconate (PbZr) has been used.
O ₃ ), lead titanate (PbTiO ₃ ), barium titanate (BaTiO ₃ ), barium phosphate and other piezoelectric substances (crystals) are mechanical energy (force) such as pressure or tension.
It is known that when is added, static electricity (charge) appears on the surface of the crystal and is electrically separated (polarization, electrification) such as plus side and minus side. The phenomenon of polarization and charging due to such mechanical strain is called a direct piezoelectric effect, and the phenomenon of deformation when a voltage is applied is called a reverse piezoelectric effect. In this case, the force acting on the crystal differs depending on the polarity of the applied voltage. When the direction of polarization and the direction of force are the same (on the same axis) in the relationship between the direction of polarization and the direction of force, it is called a piezoelectric longitudinal effect, and the relationship between the direction of polarization and the direction of force is a right angle. Is called the piezoelectric transverse effect.

[0003] Products using the above-described piezoelectric ceramics are widely used in various fields, and a piezoelectric actuator that uses displacement or force generated through a piezoelectric phenomenon as a mechanical drive source is a conventional magnetic actuator. Compared to the electromagnetic type in which a coil is wound around the body, it has excellent features such as low power consumption, fast response speed, large displacement, little heat generation, and small size and weight.

[0004] Conversion elements that convert between electric energy and mechanical energy in a piezoelectric actuator mainly include a bimorph element and a stacked element. In general, the bimorph type element is, for example, as shown in FIG. 7A, formed by bonding two piezoelectric ceramics 2 having different expansion and contraction characteristics to a metal shim material 1 with an adhesive. When a voltage is applied via electrodes (not shown), one piezoelectric plate 2 expands and the other piezoelectric plate 2 contracts, so that as a whole, bending displacement occurs. Reference numeral 4 indicates the direction of polarization. The bimorph-type element 3 has an advantage that the displacement amount is large, but has a problem in a material-specific hysteresis characteristic, a generated force, a mechanical strength, and a fatigue characteristic due to a polarization relation to an electric field,
In addition, there is a disadvantage that it is difficult to increase the resonance frequency. On the other hand, in the laminated element 5, for example, as shown in FIG. 7B, generally, several tens to several thin plates of the piezoelectric ceramics 2 are used.
00 sheets are laminated, and each sheet is alternately laminated and fixed such that the polarization 4 in the thickness direction is reversed. In the figure, 6 is an internal electrode and 7 is an external electrode. For the extraction of electrodes in the laminated element 5, the positive poles and the negative poles of the polarization 4 are connected in parallel. As a result, the direction of polarization of all the voltage ceramics becomes the same as the direction of the applied voltage, and the ceramic is displaced in the stacking direction. Compared with the bimorph type element as described above, the laminated type element 5 has an advantage that the displacement amount is small, but the response speed is remarkably high, and the generated force, conversion efficiency, and resonance frequency are large. Multilayer piezoelectric actuator 5 shown in FIG.
Is a structure utilizing the vertical effect, in which metal electrode films are provided on the front and back surfaces and piezoelectric ceramic plates 2 and metal sheets 8 polarized in the thickness direction are alternately stacked and integrated by an adhesive or the like. Each metal sheet 8 is electrically connected in parallel outside by a lead wire 9 every other layer, and an electric terminal 10 is taken out. When a voltage is applied to the electric terminal 10, the actuator 5 expands and contracts in the height direction of the arrow. On the other hand, a multilayer piezoelectric actuator 5 having a structure utilizing a vertical effect using a multilayer ceramic capacitor technique called a green sheet method as shown in FIG. 8B has also been proposed. In this structure, a large number of metal internal electrode layers 11 are embedded in layers inside the piezoelectric ceramics 2, and the internal electrodes 11 and the ceramics 2 are formed without using an adhesive.
Are integrated. Each internal electrode 11 is connected in parallel every other layer. With this structure, since a manufacturing method similar to that of the multilayer capacitor can be applied, production can be automated, and mass production can be performed at low cost. In FIG. 8 (C),
A cross-sectional view of a laminated ceramic capacitor is shown in order to compare the laminated piezoelectric actuator 5 and the laminated ceramic capacitor. From these comparisons, in the laminated piezoelectric actuator 5, there are structural differences such that the area of each internal electrode layer 11 is equal to the cross-sectional area of the ceramics 2, whereas the capacitor 12 is smaller in area. Also,
In the case of the capacitor 12, the upper and lower internal electrodes 1 to be connected
The non-overlapping part of 3 becomes piezoelectrically inactive and causes the generation of stress, and when this is used as an actuator, mechanical breakdown occurs when a voltage is repeatedly applied for a long time.

By the way, as can be seen from the above, ceramics is a ferroelectric substance, and must be polarized in order to utilize its piezoelectricity. The polarization is performed by applying an electric field to each of the two piezoelectric ceramics 2 in the case of the bimorph-type element 3 as described above. In the case of the stacked device 5, the voltage is applied by applying an electric field through the entire stacked body. For example, after heating once, cooling is performed while the electric field is being applied. And polarized so that the directions of polarization are the same. In terms of element movement due to polarization, in the case of the bimorph-type element 3 described above, when a voltage is applied to the bimorph displacement element 3 via an electrode, one piezoelectric plate 2 expands and the other piezoelectric plate 2 expands. While the piezoelectric plate 2 shrinks to cause bending displacement as a whole, in the case of the multilayer element 5, FIG.
As shown in (A), (B) and (C), it is displaced in the stacking direction and only expands and contracts in the height direction. There is also a difference that it is not. Therefore, when such a laminated element is used as a piezoelectric actuator, it is certain that it can be used for applications utilizing displacement in the laminating direction, but it is a laminated element and a bimorph type. As a result, it cannot be used as a bending type stacked element which causes bending displacement like an element. Piezoelectric actuators, for example,
When used as a warp control device for a textile machine, particularly a weaving machine or a needle selecting device for a sock knitting machine, which will be described later, the piezoelectric actuator bends and bends like a bimorph type element to bend the warp. It is preferable to allow control and selection of knitting needles at high speed.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, the present invention has a smaller displacement amount, but a significantly faster response speed, and a larger generated force, conversion efficiency, and resonance frequency than a bimorph type element. An object of the present invention is to provide a bending-type laminated piezoelectric actuator capable of bending displacement, which is a laminated element having the advantage of, in particular, a warp control device for a weaving machine, a sock knitting machine, especially for a textile machine. An object of the present invention is to provide a piezoelectric actuator that can be suitably used in the needle selecting device. The above and other objects and novel features of the present invention will become apparent from the entire description of the present specification.

[0007]

According to the present invention, a plurality of layers of piezoelectric ceramics are laminated on one side of a core material, and a plurality of layers of piezoelectric ceramics are laminated on the other side of the core material. The core material is a laminated piezoelectric actuator capable of bending displacement, characterized in that it is formed as a non-polarized piezoelectrically inactive layer.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 (A) is a sectional view of a main part of a piezoelectric actuator showing an embodiment of the present invention, FIG. 1 (B) is a piezoelectric operation explanatory view of a piezoelectric actuator showing another embodiment of the present invention, and FIG. 8] is a cross-sectional view of a main part of a piezoelectric actuator showing another embodiment of the present invention. FIG. 2 is a cross-sectional view of a needle selecting device of a sock knitting machine using the piezoelectric actuator according to an embodiment of the present invention. FIG. 3 (A), (B)
[Fig. 6] is a needle selection operation explanatory view of the piezoelectric actuator in the needle selection device of the sock knitting machine. FIG. 4 is an explanatory diagram of a sock knitting machine. FIG. 5A is a plan view of a warp control device of a weaving machine using the piezoelectric actuator according to the embodiment of the present invention, and FIG. 5B is a plan view of the warp control device according to the embodiment of the present invention. 1 is a cross-sectional view of a warp control device of a weaving machine. 6A and 6B show
FIG. 6 is a control operation explanatory diagram of the piezoelectric actuator in the warp control device of the weaving machine.

As shown in FIG. 4, in a sock pattern knitting machine such as a pattern knitting circular knitting machine or a pattern knitting flat knitting machine, a pattern knitting procedure stored in a storage device such as a floppy disk is transmitted to the vertical movement of a knitting needle. For needle selection device (needle selection piezoelectric actuator)
Is used. A large number of needle selecting devices 15 for controlling the vertical movement of the knitting needles 14 are arranged around the knitting cylinder 16, and the needle selecting devices 15 are connected to a patterning controller 17,
The pattern knitting procedure is sent from the patterning controller 17 and the knitting needle 14 is moved up and down to perform pattern knitting of the sock. Although not shown here, at the bottom of the knitting needle,
A number of needle selection jacks having a bat protruded are arranged, and a number of knitting needles 14 are brought into contact with the upper portion of the jack to form a knitting cylinder.
The knitting yarn 18 is supplied from the bobbin 19 to the needle selection device 16.
5 acts on the needle selection jack to form the knitting needle 14 as described above.
Up and down to perform knitting of socks. Note that the needle selecting device 15 may directly act on the knitting needle 14.

As shown in FIG. 2, one example of the needle selecting device 15 has a piezoelectric actuator 20 supported in multiple stages on a support (housing) 21, and a finger 22 is attached to an end of the piezoelectric actuator 20. The leading end is made to protrude from the opening 24 of the stopper 23 of the support 21 to the outside.
The piezoelectric actuator 20 is operated via 5 and the fingers 22 are actuated to move the knitting needle 14 up and down as described above to perform knit knitting of socks.

An example of the needle selecting operation will be described with reference to a piezoelectric press method. As shown in FIG. 3B, a voltage is applied from the patterning controller 17 to the piezoelectric actuator 20 via the lead wire 25 as shown in FIG. (Or when a positive pulse is applied), the piezoelectric actuator 20 is bent, the finger 22 is turned downward, for example, and the butt 27 of the needle selection jack 26 is not pressed. The vertical position is maintained, so that the raising cam butt 28 at the lower end of the needle selecting jack 26 engages with the raising cam 29, thereby causing the needle selecting jack 26 and the knitting needle 14 abutting thereon to move upward, and as a result, The stitches are formed by the knitting needles 14. On the other hand, as shown in FIG. 3A, when no voltage is applied (or when a negative pulse is applied), the piezoelectric actuator 20 does not bend, so that the butt 27 of the needle selection jack 26 is pressed. Therefore, the butt 28 for the raising cam at the lower end of the needle selection jack 26
Does not engage the raising cam 29, and does not give a knitting operation to the mesh needle 14 that is in contact with the upper portion of the needle selection jack 26.

Next, the piezoelectric actuator in the warp control device of the weaving machine will be described with reference to FIGS. The general principle of a loom is that in the case of plain weave, the warp thread is passed through a heddle, and the upper and lower parts of the heald are divided into two groups to form an opening, and a weft thread is inserted into the opening by a shuttle, Press it forward, then make another combination of warp threads, put the weft threads in it and proceed with weaving. Piezoelectric actuators are used to control the healds, and thus the warp yarns. As shown in FIGS. 5 and 6, a finger 22 is attached to an end portion of the piezoelectric actuator 20, and although not shown, the piezoelectric actuator 20 and the heald control device are electrically connected to each other, and the piezoelectric actuator is connected. 20 is operated and the fingers 22 are operated to control a heald (not shown) connected to the lower portion of the control rod 31, and further, control a warp thread. The operation is such that when a voltage (pulse) is applied to the piezoelectric actuator 20, the piezoelectric actuator 20
Is bent and displaced, and since the finger 22 is connected to the piezoelectric actuator 20, the finger 22 also follows the bending displacement (curving movement) of the piezoelectric actuator 20. Since the finger 22 is provided with the hook portion 30 (which may be a hook hole), the control rod 31 similarly provided with the hook portion or the hole 310 is engaged with the finger 22 and, on the other hand, Piezoelectric actuator 20
When no voltage (pulse) is applied to the finger 22, the finger 22 does not engage the control rod 31 and keeps the separated position, and thus the finger 22 selectively engages and holds the control rod 31. You can As described above, the control rod 31
Although not shown in the drawing, is connected to the heald at the hook portion or the lower portion of the hole 310. The control rod 31 is operatively linked to the heald, controls the heald, and controls the warp thread.

The laminated piezoelectric actuator of the present invention is the piezoelectric actuator 20 in the textile machine as described above.
Can be used as As shown in FIG. 1 (A), the piezoelectric actuator 20 is of a laminated type and has a core material 32.
, A plurality of layers 2 of piezoelectric ceramics are laminated on one side, and a plurality of layers 2 of piezoelectric ceramics are laminated on the other side of the core material 32. As a piezoelectrically inactive layer of polarization.

The core material 32 is a non-polarized, non-polarized, piezoelectrically inactive layer. In this case, the core material 32 and the layers 2 of the piezoelectric ceramics, which are laminated with the core material 32 as a boundary, are formed.
The inventors of the present invention have made diligent studies to find that a laminated piezoelectric actuator capable of bending displacement cannot be obtained when a polarized layer is used as in the case of ... And a polarized piezoelectric layer is used.

In order to obtain a laminated piezoelectric actuator capable of more bending displacement, a plurality of piezoelectric ceramic layers 2 laminated on one side of the core material 32 and the other one side of the core material 32. With respect to the plurality of layers 2 of piezoelectric ceramics laminated on the core material 32, the respective polarization forms 33 may be reverse polarization as shown in the figure, for example.

Various piezoelectric substances (crystals) can be used as the piezoelectric substance (crystals) forming the piezoelectric ceramics 2. For example, as specific examples, lead zirconate (PbZrO ₃ ) called PZT and lead titanate (PbTi
O ₃ ), lead zirconate (PbZrO ₃ ), lead titanate (PbTiO ₃ ), barium titanate (BaTI)
O ₃ ), barium phosphate and the like. Additives such as Nb, Co, and Mn can be added to the piezoelectric material. It may be a complex with a polymer substance or the like.

Examples of the core material 32 include ceramics and metal materials. However, it is preferable to use the above-mentioned piezoelectric material for the core material 32. That is, the layers 2 of piezoelectric ceramics, which are laminated with the core material as a boundary,
It is preferable to use the same material as the ceramics forming the. As will be described later, this is performed by matching the thermal expansion coefficient by using the same material,
This is because peeling at the interface between the piezoelectric ceramics layer 2 and the piezoelectric ceramics layer 2 can be prevented, and in the conventional bimorph type element, two piezoelectric ceramics having different expansion and contraction characteristics are bonded to the metal shim material by an adhesive because of its manufacturing. It has a drawback that it easily peels off at the interface, and this can be prevented.

In order to obtain a laminated piezoelectric actuator that can be more flexibly displaced, the thickness of each layer 2 of the piezoelectric ceramics laminated with the core material 32 as a boundary is as shown in FIG. 1 (C). It is preferable that the core material 32 be gradually thinned toward the outside. For example, if the thickness of the piezoelectric ceramics layer 2 in contact with the core material 32 is assumed to be a thickness t, the thickness of the piezoelectric ceramics layer 2 on the outer side is t−χ _1, and then t−χ ₂ , t-χ ₃ ... t-χ _n (however,
χ ₁ <χ ₂ <χ ₃ <χ _n ), and the thickness may be successively reduced.

The laminated piezoelectric actuator according to the present invention can be obtained, for example, as follows. Organic solvents, binders, plasticizers and dispersants, etc. are added to the calcined powder of piezoelectric ceramics, mixed, and a green sheet is manufactured.
Punching into an appropriate size, screen-printing a conductor paste for internal electrodes made of Ag-Pd, Pd, etc., stacking a required number of these green sheets, press-molding, and integrating. At that time, it is preferable that the green sheets to be stacked on top of and below the green sheet to be the core material are successively thinned. Heating with a press (usually 500-600 ° C)
Then, it is fired at, for example, about 1200 ° C. to obtain a ceramics laminate. After cutting the laminate, insulation and external electrodes are attached. Every other inner electrode is electrically connected in parallel. other,
For manufacturing the multilayer piezoelectric actuator, a technique of a multilayer ceramic capacitor called the green sheet method can be used.

The laminated body thus obtained is polarized in order to utilize its piezoelectricity. The polarization can be performed, for example, in air or in silicone oil. An electric field cooling method or the like may be used in which heating is performed once to the Curie point or more, and then cooling is performed gradually while applying an electric field. At that time, the core material 32
Is a non-polarized, non-polarized, piezoelectrically inactive layer. Also,
At that time, a plurality of piezoelectric ceramic layers 2 laminated on one side of the core material 32, and a plurality of piezoelectric ceramic layers 2 laminated on the other one side of the core material 32.
Each of the polarization forms 33 of and is preferably reverse polarized with the core material 32 as a boundary.

The bending type laminated piezoelectric actuator may be manufactured integrally by using an adhesive, but as described above, the same material is used throughout without using the adhesive. It is preferable to integrate them by interposing the internal electrode conductor paste. As a result, when manufacturing a bimorph type element, two piezoelectric ceramics having different expansion and contraction characteristics are adhered to the metal shim material with an adhesive in the manufacturing process, and they are separated at the interface,
In addition, there is a drawback that an adhesive process is added and the cost is increased, but this can be avoided. If they are made of the same material and integrated without using an adhesive, the adhesive strength is improved, the adhesive process can be omitted, and the cost can be reduced.
Moreover, if they are made of the same material, the coefficients of thermal expansion can be matched, and in that respect as well, the adhesive strength is improved, and it is not necessary to separately prepare a metal material in manufacturing.

When the piezoelectric actuator is used in the warp control device of the above weaving machine or the needle selecting device of the sock knitting machine, as shown in the above embodiment, it does not hinder the bending motion of the piezoelectric actuator 20. Is preferred. In the method, in the example of the needle selecting device 15 of the sock knitting machine, a spherical body 34 is attached to the rear end of the piezoelectric actuator 20, and the rear end of the piezoelectric actuator 20 to which the spherical body 34 is attached is attached to a support body. 21 is fitted into the groove 36 of the piezoelectric actuator mounting portion 35 to allow the spherical portion of the spherical body 34 to move within the groove 36 of the piezoelectric actuator mounting portion 35, and accordingly, the rear end portion of the piezoelectric actuator 20 is moved. It is movable. Further, a spherical body 34 similar to the above is attached to the tip end portion of the piezoelectric actuator 20 so that the spherical body 34 can move within the rear end portion 37 of the finger 22, and thereby the piezoelectric actuator 20. The tip of the can also be moved. Further, the rotary body 38 is fixedly attached to the piezoelectric actuator 20 at a position midway between the rear end portion and the front end portion of the piezoelectric actuator 20, and both ends of the rotary body 38 are rotated to the rotary body mounting portion (halfway fulcrum portion) 39 of the support body 21. It is erected so that the movement of the piezoelectric actuator 20 at the middle position between the rear end portion and the front end portion is not stopped as the rotary body 38 rotates. According to this method and device, since the piezoelectric actuator 20 is freely movable, its movement is not hindered, and a midpoint fulcrum is formed, the needle selection speed can be significantly increased, and the piezoelectric actuator 20 has a long life. There are excellent advantages such as In this respect, the same applies to the warp control device of the weaving machine. A spherical body 34 is attached to the upper end of the piezoelectric actuator 20, and the spherical body 34 is supported (control rod retainer) 2
1 is movably supported in the groove 36 and the lower end thereof is movably connected to the finger 22, and the middle position between the upper end and the lower end of the piezoelectric actuator 20 is The control rod holder 21 is rotatably attached to a rotating body 38 so that the upper end portion and the lower end portion of the piezoelectric actuator 20 and their intermediate positions can be moved following the bending movement of the piezoelectric actuator 20. If the bending movement of the piezoelectric actuator 20 is not hindered, the speed of the control operation of the control rod 31, the heald, and the selection control operation of the warp yarn can be improved, and the life of the piezoelectric actuator 20 can be extended. And the applied voltage can be further lowered.

Although the invention made according to the present invention has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say. The warp control device of the weaving machine of the present invention uses a card having holes corresponding to the pattern proposed by Jacquard, and pulls up only the vertical needle at a position corresponding to the hole of the card. It is mainly used in a jaguar device that pulls up only the warp thread connected to the vertical needle through the thread and creates a higuchi between the pulled up warp thread and the warp thread that remains in the original position. INDUSTRIAL APPLICABILITY The present invention can be applied to a needle selection device for a sock knitting machine as a rake-up type piezoelectric actuator instead of the press type. In the above embodiment, an example in which the present invention is applied to a textile machine is shown, but the present invention can also be applied as a piezoelectric actuator in various fields other than the textile machine, for example, a positioner (positioning tool), a printer head, Sound wave motors, piezoelectric relays, piezoelectric valves, electronic calculators, related equipment (computers, printers), consumer electronic equipment (TVs, radios, VTRs), office equipment, office supplies (copiers, typewriters), precision equipment (cameras, It can be used in various fields such as watches.

[0024]

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows. That is, according to the present invention, as compared with the bimorph type element, the displacement amount is small, the response speed is much faster, the generated force, the conversion efficiency, the laminated element having the advantage that the resonance frequency is large, A bending-type laminated piezoelectric actuator capable of bending displacement can be provided, and in particular, for a textile machine, a piezoelectric actuator that can be suitably used as a warp control device of a weaving machine and a needle selection device of a sock knitting machine can be provided. Can be provided.

[Brief description of the drawings]

FIG. 1 (A) is a cross-sectional view of a main part of a piezoelectric actuator showing an embodiment of the present invention, and FIG. 1 (B) is a piezoelectric operation explanatory view of a piezoelectric actuator showing another embodiment of the present invention. FIG. 1C is a cross-sectional view of a main part of a piezoelectric actuator showing another embodiment of the present invention.

FIG. 2 is a sectional view of a needle selecting device of a sock knitting machine using the piezoelectric actuator according to an embodiment of the present invention.

FIGS. 3 (A) and 3 (B) are explanatory diagrams of a needle selecting operation of a piezoelectric actuator in a needle selecting device of the sock knitting machine, respectively.

FIG. 4 is an explanatory view of a sock knitting machine.

FIG. 5A is a plan view of a warp control device of a weaving machine using the piezoelectric actuator according to an embodiment of the present invention, and FIG. 5B is a plan view illustrating an embodiment of the present invention. It is a sectional view of a warp control device of a weaving machine in which a piezoelectric actuator is used.

FIGS. 6 (A) and 6 (B) are explanatory diagrams each illustrating a control operation of a piezoelectric actuator in a warp control device of the weaving machine.

FIG. 7A is a configuration diagram of a conventional bimorph type piezoelectric element, and FIG. 7B is a configuration diagram of a conventional multilayer piezoelectric element.

FIGS. 8A, 8B, and 8C are configuration diagrams of a conventional laminated piezoelectric element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal shim material 2 ... Piezoelectric ceramics 3 ... Bimorph type element 4 ... Polarization direction 5 ... Laminated type element 6 ... Internal electrode 7 ... External electrode 8 ... Metal sheet 9 ... Lead wire 10 ... Electrical terminal 11 ... Metal internal electrode Layer 12: Multilayer ceramic capacitor 13: Internal electrode 14: Knitting needle 15: Needle selecting device 16: Knitting cylinder 17: Patterning controller 18: Knitting thread 19: Bobbin 20: Piezoelectric actuator 21: Support body (housing) 22: Finger 23 ... Stopper part 24 ... Opening part 25 ... Lead wire 26 ... Needle selection jack 27 ... Bat 28 ... Bat for raising cam 29 ... Rising cam 30 ... Hook part 31 ... Control rod 32 ... Core material 33 ... Polarized form 34 ... Spherical form Body 35: Piezoelectric actuator mounting portion 36: Groove 37: Rear end of finger 22 38: Rotating body 39: Rotating body With section

Claims (7)

[Claims] 1. A plurality of layers of piezoelectric ceramics are laminated on one side of a core material, and a plurality of layers of piezoelectric ceramics are laminated on the other side of the core material, wherein the core material is a non-polarized piezoelectric material. A laminated piezoelectric actuator capable of bending displacement, which is formed as an active layer. 2. The laminated piezoelectric actuator according to claim 1, wherein the polarization forms of a plurality of layers of the piezoelectric ceramics laminated with the core material as a boundary are configured to be reverse polarization. 3. The laminated piezoelectric actuator according to claim 1, wherein the core material is made of ceramics. 4. The core material is made of metal.
The laminated piezoelectric actuator according to any one of claims. 5. The laminated piezoelectric actuator is a laminated piezoelectric actuator for textile machines,
The laminated piezoelectric actuator according to claim 1. 6. The laminated piezoelectric actuator according to claim 1, wherein the laminated piezoelectric actuator for a textile machine is a piezoelectric actuator in a warp control device of a weaving machine. 7. The laminated piezoelectric actuator according to claim 1, wherein the laminated piezoelectric actuator for a textile machine is a piezoelectric actuator in a needle selection device of a sock knitting machine.