JP5288436B2 - Honeycomb type piezoelectric / electrostrictive element - Google Patents

Description

  The present invention relates to a honeycomb-type piezoelectric / electrostrictive element, and more particularly to a honeycomb-type piezoelectric / electrostrictive element that is excellent in durability, is suitable for weight reduction, and can be manufactured at low cost.

Piezoelectric actuators capable of high-speed response are used as opening / closing actuators and precision positioning actuators for fuel injection valves of diesel engines. Normally, the piezoelectric actuator has a very large generated force of 3 kg / mm ² level, but the displacement is as small as 0.1 mm or less.

As actuators that have been devised to increase the displacement, currently, stacked piezoelectric actuators in which thin piezoelectric plates sandwiching electrodes are stacked and integrated have become the mainstream (see, for example, Patent Documents 1 to 3). A spiral actuator has also been proposed (see, for example, Patent Document 4). Of these, the laminated actuator is usually manufactured by the following method. First, a raw tape (sheet) having a thickness of several tens of μm is produced by a doctor blade method or the like, and cut into an appropriate size to produce a green sheet. Next, an electrode paste made of a high heat-resistant metal that can withstand the piezoelectric sintering temperature, such as Pt or Ag / Pd, is printed and applied on one side of the green sheet, and several hundreds of these are laminated . The obtained green laminate is subjected to binder removal and then fired at 1000 ° C. or higher to be sintered. After cutting this into a desired size and shape, a multilayer actuator can be obtained by connecting each internal electrode to an external electrode provided on the side surface of the sintered body.
JP-A-6-120579 JP 2002-261339 A JP 2004-297042 A Japanese Patent Laid-Open No. 11-112046

  In such a multilayer actuator, there is generally an inactive region (inactive portion) where no electrode is formed at the peripheral portion of each layer. This inactive portion has a problem in durability, such as a tensile stress generated by driving and deformation of the active portion, and a crack easily occurs. On the other hand, there is a configuration in which electrodes are formed on the entire surface, but a complicated process of providing a coating made of an insulating material over almost the entire width is required on the edge of the internal electrode exposed on the side surface (patent) Reference 1). Further, the external electrode connecting the electrodes between the layers also has a problem in durability, such as being subject to tensile stress due to the expansion and contraction movement of the actuator, and being easily cut. For this reason, complicated processes, such as sticking a metal mesh, were needed (refer to patent documents 2). In addition, since the multilayer actuator is likely to cause delamination due to shear stress generated between each layer of the piezoelectric body and the electrode, it has been necessary to devise a mechanism to operate with an appropriate preload applied (Patent Document) 3).

  In addition, since a multilayer actuator often uses a lead-based piezoelectric material having a specific gravity of about 8, the mass tends to increase when a dense bulk structure is used. Cylindrical actuators have also been proposed in order to achieve both an area to be displaced and an amount of displacement while suppressing an increase in mass, but there has been a problem that processing costs increase as the aspect ratio of the element increases.

  The production of a laminated actuator usually consists of a very large number of processes, which is a cause of high costs. In addition, in a multilayer actuator, since a piezoelectric material and an internal electrode are generally fired simultaneously in the manufacturing process, an expensive noble metal such as Pt or Ag / Pd having a heat resistance of 1000 ° C. or higher is used for the electrode. It was necessary to use the contained material, which caused high costs.

  In order to solve the durability problem among the problems of the multilayer actuator, an actuator having a spiral structure has been proposed (see Patent Document 4). According to this spiral structure actuator, the piezoelectric ceramic layer and the vibrating electrode are spirally wound to form a substantially cylindrical shape, and the durability is more advantageous than the stacked type, but the mass is There is no improvement in terms of large points and high manufacturing costs.

  The present invention has been made in view of the above problems, and is characterized by providing a honeycomb-type piezoelectric / electrostrictive element that is excellent in durability, is suitable for weight reduction, and can be manufactured at low cost.

  In order to achieve the above object, the present invention provides the following honeycomb type piezoelectric / electrostrictive element.

[1] A honeycomb structure having partition walls that partition and form a plurality of cells penetrating in the axial direction, and an electrode (internal electrode) disposed on the inner wall surface of the cell so as to cover the entire inner wall surface from the inside The partition is a piezoelectric / electrostrictive body, and the honeycomb structure can be deformed by applying a voltage between the electrodes disposed in adjacent cells across the partition , the honeycomb One end face of the structure part has one external electrode connected to a predetermined internal electrode having the same polarity, and another external electrode connected to the remaining internal electrode having the same polarity, A honeycomb-type piezoelectric / electrostrictive element, which is a pair of external electrodes for applying a voltage between one external electrode and the other external electrode .

[2] The honeycomb-type piezoelectric / electrostrictive element according to [1], wherein the internal electrodes are arranged in all the cells, and a voltage can be applied between all the cells adjacent to each other across the partition wall. .

[ 3 ] The cell has a conductive plugging portion in contact with the internal electrode at one end of the cell, and the one external electrode and the other external electrode are connected to the predetermined plug via the plugging portion. The honeycomb-type piezoelectric / electrostrictive element according to [ 1 ] or [2] , which is connected to each of the internal electrodes and the remaining internal electrodes.

[ 4 ] An insulating protective film in a lattice shape so as to cover the partition wall and the internal electrode along the partition wall and to expose the plugging portion on the end surface of the honeycomb structure portion where the external electrode is disposed along the partition wall. There is provided, the external electrodes, wherein while being disposed on the surface of the insulating protective film, according to [3] connected to the plugging portion exposed from the opening portions of the grid-shaped insulating protective film Honeycomb type piezoelectric / electrostrictive element.

[ 5 ] The honeycomb according to any one of [ 1 ] to [ 4 ], wherein the predetermined internal electrodes having the same polarity and the remaining internal electrodes having the same polarity are alternately arranged. Type piezoelectric / electrostrictive element.

[ 6 ] The honeycomb-type piezoelectric / electrostrictive element according to any one of [1] to [ 5 ], wherein a cross-sectional shape perpendicular to the longitudinal direction of the cell is a quadrangle with arcuate corners.

[ 7 ] The honeycomb type piezoelectric / electrostrictive element according to any one of [1] to [ 6 ], wherein the partition wall has a thickness of 20 to 500 μm.

[ 8 ] The honeycomb according to any one of [1] to [ 7 ], wherein the honeycomb structure is formed by firing a material formed by extrusion forming a piezoelectric / electrostrictive material as a main component. Type piezoelectric / electrostrictive element.

[ 9 ] The honeycomb type piezoelectric element according to any one of [1] to [ 8 ], wherein the honeycomb structure part is formed by firing a laminate of green sheets mainly composed of a piezoelectric / electrostrictive material. / Electrostrictive element.

[1 0 ] The honeycomb-type piezoelectric / electrostrictive element according to any one of [1] to [ 9 ], wherein the internal electrode has a thickness of 0.05 to 5 μm.

  According to the honeycomb type piezoelectric / electrostrictive element of the present invention, the honeycomb structure portion having partition walls made of a piezoelectric / electrostrictive body is provided, and the inner electrode is provided on the inner wall surface of the cell defined by the partition walls. When a voltage is applied between the internal electrodes arranged in adjacent cells, the partition is deformed so as to extend in the thickness direction (d33 direction) and contract in the direction perpendicular to the thickness direction (d31 direction). Is possible. In this way, when the partition wall is deformed so as to extend in the thickness direction and contract in the direction perpendicular to the thickness direction, the honeycomb type piezoelectric / electrostrictive element has a cell penetration direction (center axis direction). And further shrinks in a plane perpendicular to the cell penetration direction. In addition, since the partition walls extend in the thickness direction, the cell space is narrowed. As described above, it is possible to use as an actuator or the like by utilizing the characteristic that the entire electrode including the direction through which the cell penetrates is applied by applying a voltage to the internal electrode.

  The honeycomb-type piezoelectric / electrostrictive element of the present invention is excellent in durability because there are few inactive portions as compared with the multilayer actuator. In addition, since the piezoelectric body and the internal electrode are not laminated and the piezoelectric body has an integral structure, there is no delamination due to shear stress generated between the layers during expansion and contraction of the actuator, which is a problem with the laminated type, and preloading It is excellent in durability.

  Further, in the honeycomb type piezoelectric / electrostrictive element of the present invention, in order to dispose the internal electrode on the inner wall surface of the cell, the honeycomb structure including the piezoelectric / electrostrictive body is first manufactured, and then the internal electrode is disposed. It is possible. As a result, it is not necessary to expose the internal electrode to a high temperature during firing, and it is not necessary to use an expensive noble metal such as Pt or Ag / Pd, so that it can be manufactured at low cost.

  In addition, since the honeycomb type piezoelectric / electrostrictive element of the present invention has a plurality of cell spaces inside, it is possible to reduce the weight of the structure.

  Furthermore, the application of the honeycomb type piezoelectric / electrostrictive element of the present invention is not limited to an actuator, and may be used as a sensor element for various sensors such as an ultrasonic sensor, an acceleration sensor, an angular velocity sensor, an impact sensor, and a mass sensor. Is possible.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings.However, the present invention is not limited to the following embodiments and is within the scope of the present invention. It should be understood that design changes, improvements, and the like can be made as appropriate based on ordinary knowledge of those skilled in the art.

  1A and 1B schematically show an embodiment of the honeycomb-type piezoelectric / electrostrictive element of the present invention, FIG. 1A is a perspective view, and FIG. 1B is an enlarged view of “part A” of FIG. 1A. It is a perspective view. As shown in FIGS. 1A and 1B, the honeycomb-type piezoelectric / electrostrictive element 100 of the present embodiment has a honeycomb structure having partition walls 3 for partitioning and forming a plurality of cells 2 penetrating in the axial direction (center axis direction) P. The part 1 and the electrode (internal electrode) 5 disposed on the inner wall surface 4 of the cell 2 so as to cover the entire inner wall surface 4 from the inside are provided. The inner wall surface 4 of the cell 2 is the surface of the partition wall 3 that forms the cell 2. The partition wall 3 is a piezoelectric / electrostrictive body, and a voltage is applied between the electrodes (internal electrodes) 5 and 5 disposed in the adjacent cells 2 and 2 with the partition wall 3 interposed therebetween to deform the honeycomb structure portion. It is a honeycomb-type piezoelectric / electrostrictive element that can be used.

  Thus, since the partition wall 3 is made of a piezoelectric / electrostrictive body and the internal electrode 5 is provided on the inner wall surface 4 of the cell 2, the internal electrodes 5 and 5 disposed in the adjacent cells 2 and 2 with the partition wall 3 interposed therebetween. When a voltage is applied between them, the partition wall can be deformed so as to extend in the thickness direction (d33 direction) and contract in a direction perpendicular to the thickness direction (d31 direction). For example, as shown in FIG. 1B, the central axis direction P of the honeycomb-type piezoelectric / electrostrictive element corresponds to a direction perpendicular to the thickness direction of the partition walls 3, and thus the partition walls 3 are indicated by arrows a1 and a2. Deform to shrink in the direction. Also, in the direction perpendicular to the thickness direction of the partition 3 on the plane (end surface and cross section) perpendicular to the central axis direction P of the honeycomb type piezoelectric / electrostrictive element, the partition 3 is in the direction indicated by the arrows a3 and a4. , And so as to shrink in the direction indicated by arrows a5 and a6. Further, in the thickness direction of the partition walls 3 in the plane (end surface and cross section) perpendicular to the central axis direction P of the honeycomb type piezoelectric / electrostrictive element, the partition walls 3 are deformed so as to extend in the directions indicated by the arrows a7 and a8. To do. Thus, since the partition wall 3 is deformed so as to extend in the thickness direction and contract in a direction perpendicular to the thickness direction, the honeycomb-type piezoelectric / electrostrictive element 100 has a direction in which the cell 2 penetrates (center axis direction P ), And further shrinks as a whole in a plane orthogonal to the direction in which the cell 2 penetrates (center axis direction P). The partition wall 3 is deformed so as to extend in the thickness direction. However, since the space of the cell 2 is formed in the thickness direction of the partition wall 3, the deformation of the partition wall 3 in the thickness direction is the space of the cell 2. The contribution to the change in the external shape of the honeycomb type piezoelectric / electrostrictive element 100 is small. As described above, the honeycomb-type piezoelectric / electrostrictive element 100 according to the present embodiment operates to shrink as a whole including the cell penetration direction (center axis direction P) by applying a voltage to the internal electrode. Using this characteristic, it can be used as an actuator element or a sensor element.

  Further, in the honeycomb-type piezoelectric / electrostrictive element 100 of the present embodiment, the cell 2 in which the internal electrode 5 is disposed on the entire surface (end surface and cross section) on the surface (end surface and cross section) perpendicular to the central axis direction P. Due to the arrangement, the inactive portion is few and the durability is excellent as compared with the multilayer actuator. In addition, since the piezoelectric body (partition wall 3 (piezoelectric / electrostrictive body)) and the internal electrode 5 are not laminated and the piezoelectric body has an integral structure, it is a problem with the laminated type. There is no delamination due to the generated shear stress, no need for preload, and excellent durability. In the honeycomb-type piezoelectric / electrostrictive element 100 of the present embodiment, the internal electrode 5 is disposed on the inner wall surface 4 of the cell 2, so that the honeycomb structure portion 1 including the piezoelectric / electrostrictive body (partition wall 3) is first manufactured. Then, the internal electrode 5 can be disposed thereafter. Thereby, the internal electrode 5 does not need to be exposed to a high temperature at the time of firing when the honeycomb structure portion 1 is manufactured, and it is not necessary to use an expensive noble metal such as Pt, Ag / Pd, etc. Is possible. In addition, since the honeycomb type piezoelectric / electrostrictive element 100 of the present embodiment has the spaces of the plurality of cells 2 inside, it is possible to reduce the weight of the structure.

  The partition walls 3 of the honeycomb structure portion 1 constituting the honeycomb type piezoelectric / electrostrictive element 100 of the present embodiment are piezoelectric / electrostrictive bodies. The piezoelectric / electrostrictive material constituting the piezoelectric / electrostrictive body is not particularly limited as long as it is a material that causes electric field induced strain, and may be crystalline or amorphous, and may be a semiconductor ceramic material or a strong material. A dielectric ceramic material or an antiferroelectric ceramic material may be used. What is necessary is just to select and employ | adopt suitably according to a use. Further, it may be a material that does not require polarization treatment or a material that does not need polarization treatment.

  Specifically, lead zirconate, lead titanate, lead magnesium niobate, lead nickel niobate, lead nickel tantalate, lead zinc niobate, lead manganese niobate, lead antimony stannate, lead manganese tungstate, cobalt niobium Lead oxide, lead magnesium tungstate, lead magnesium tantalate, barium titanate, sodium bismuth titanate, bismuth neodymium titanate (BNT), sodium niobate, potassium sodium niobate, strontium bismuth tantalate, barium copper tungsten, iron acid Examples thereof include bismuth or a composite oxide composed of two or more of these. These materials include lanthanum, calcium, strontium, molybdenum, tungsten, barium, niobium, zinc, nickel, manganese, cerium, cadmium, chromium, cobalt, antimony, iron, yttrium, tantalum, lithium, bismuth, tin, An oxide such as copper may be dissolved. Among these, materials containing nickel oxide with a composite oxide of lead zirconate, lead titanate and lead magnesium niobate as the main component, lead zirconate, lead titanate, lead magnesium niobate and lead nickel niobate A material containing a composite oxide as a main component is preferable because a large electric field induced strain can be used. Here, the main component refers to a component whose content exceeds 50% by mass. In this case, the nickel component is particularly preferably 0.05 to 3% by mass in terms of oxide. In addition, a material obtained by adding lithium bismutate, lead germanate, or the like to the above material is preferable because it can exhibit high material properties while realizing low-temperature firing of the piezoelectric / electrostrictive body. In particular, the above lead zirconate, titanium A material comprising nickel oxide as a main component of a composite oxide of lead oxide and lead magnesium niobate, containing 0.05 to 3% by mass in terms of oxide as the nickel component, and germanic acid A material containing 0.3 to 4% by weight of lead; a material mainly composed of a composite oxide of lead zirconate, lead titanate, lead magnesium niobate, and lead nickel niobate, and its nickel component A material containing 0.05 to 3% by mass in terms of oxide and 0.3 to 4% by mass of lead germanate is desirable.

  In the honeycomb structure 1 constituting the honeycomb type piezoelectric / electrostrictive element 100 of the present embodiment, an outer peripheral wall 6 is disposed so as to surround the entire outermost periphery of the partition wall 3. The partition wall 3 is a piezoelectric / electrostrictive body, but the outer peripheral wall 6 may be a piezoelectric / electrostrictive body or other ceramic material.

There is no restriction | limiting in particular about the magnitude | size of the honeycomb type piezoelectric / electrostrictive element 100 of this embodiment, According to a use, it can select suitably. For example, when used for an opening / closing actuator of a fuel injection valve of an internal combustion engine, the cross-sectional area is preferably about 0.3 to 1.5 mm ² and the length is about 30 to 80 mm.

  In the honeycomb type piezoelectric / electrostrictive element 100 of the present embodiment, the thickness of the partition wall 3 is not particularly limited, but is preferably 20 to 500 μm, more preferably 30 to 80 μm, and more preferably 30 to 50 μm. It is particularly preferred. Moreover, when it has the outer peripheral wall 6, it is preferable that the thickness is 50-200 micrometers.

  When the honeycomb has a square shape, when the film thickness is A μm and the cell dimension is B μm, A / B is preferably 0.02 to 0.3, more preferably 0.04 to 0.2, and 0.06 to 0.1 is particularly preferred. Further, the number of cells formed in the honeycomb type piezoelectric / electrostrictive element 100 is preferably 10 to 1000, and more preferably 40 to 500.

  In the honeycomb type piezoelectric / electrostrictive element 100 of the present embodiment, the shape of the cross section perpendicular to the central axis of the honeycomb structure portion 1 may be a quadrangle as shown in FIG. 1A, but other than a pentagon, a hexagon, etc. It may be a polygonal shape, or may be another shape such as a circle, an ellipse, or a track shape. Further, the cross-sectional shape perpendicular to the central axis of the cell 2 (perpendicular to the longitudinal direction) may be a quadrangle as shown in FIG. 1A, but may be another polygon such as a pentagon or a hexagon. In addition, other shapes such as a polygon such as a quadrangle whose corners are arc-shaped, a circle, an ellipse, and a track shape may be used. Here, when referring to “a quadrangle with corners in an arc shape”, as shown in FIG. 2, in the cross-sectional shape perpendicular to the longitudinal direction of the cell 2, four corners (portions corresponding to the apexes) 2 a are formed. This refers to a quadrangular shape formed into a circular arc shape. Such a shape of the cell is preferable in that it can prevent electric field concentration in the portion corresponding to the corner portion of the internal electrode disposed in the cell. FIG. 2 is an enlarged cross-sectional view of a part of a cross section perpendicular to the central axis of a honeycomb structure portion constituting another embodiment of the honeycomb type piezoelectric / electrostrictive element of the present invention.

  In the honeycomb-type piezoelectric / electrostrictive element 100 of the present embodiment, the honeycomb structure portion 1 is preferably formed by firing a material formed by extrusion forming a piezoelectric / electrostrictive material as a main component. . As a result, the honeycomb-type piezoelectric / electrostrictive element 100 can be efficiently manufactured with fewer steps, and the manufacturing cost can be reduced. Alternatively, the honeycomb structure portion 1 may be formed by firing a laminate of green sheets mainly composed of a piezoelectric / electrostrictive material. Here, the phrase “having the piezoelectric / electrostrictive material as a main component” means that the content of the piezoelectric / electrostrictive material with respect to the entire powder component constituting the forming raw material exceeds 50 mass%.

  In the honeycomb type piezoelectric / electrostrictive element 100 of the present embodiment, the number of the internal electrodes 5 and the arrangement of the internal electrodes 5 are arranged such that at least one partition wall 3 is sandwiched between the internal electrodes 5 and 5. Although not particularly limited, as shown in FIG. 1A, the internal electrodes 5 are arranged in all the cells 2 so that a voltage can be applied between all the cells 2 adjacent to each other with the partition wall 3 interposed therebetween. It is preferable to do. The internal electrode 5 is preferably formed in a cylindrical shape so as to cover the entire inner wall surface of the cell 2. Thereby, since all the partition walls 3 are deformed in the predetermined direction when a voltage is applied to the internal electrode 5, it is possible to obtain a piezoelectric / electrostrictive element having a large generated force. As shown in FIG. 1A, internal electrodes 5 are disposed in all the cells 2, and in order to apply a voltage between all the adjacent cells 2 across the partition wall 3, a predetermined internal electrode 5 a having the same polarity, It is preferable that the remaining internal electrodes 5b having the same polarity are alternately arranged so that a voltage is applied between the internal electrodes 5a and 5b. Here, when the internal electrodes 5a and the internal electrodes 5b are alternately arranged, as shown in FIG. 1A, the internal electrodes 5a and the internal electrodes 5b are alternately arranged in the vertical direction and the horizontal direction on the end surface.

  In the honeycomb type piezoelectric / electrostrictive element 100 of the present embodiment, the thickness of the internal electrode 5 is not particularly limited, but is preferably 0.05 to 5 μm, more preferably 0.1 to 1 μm, and 0 It is particularly preferable that the thickness is 1 to 0.5 μm. When the thickness is less than 0.05 μm, the resistance of the electrode is increased, and a sufficient electric field is not applied to the piezoelectric / electrostrictive body. When the thickness is more than 5 μm, the inhibition of displacement cannot be ignored as an inactive portion.

  The internal electrode 5 is preferably made of a conductive metal that is solid at room temperature. For example, simple metals or alloys containing aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, etc. Can be mentioned. In the honeycomb-type piezoelectric / electrostrictive element 100 of the present embodiment, it is not necessary to use an expensive noble metal such as Pt or Ag / Pd as described above, and therefore other inexpensive materials can be used. .

  As shown in FIG. 3, the honeycomb type piezoelectric / electrostrictive element 100 of the present embodiment has one external electrode 7 in which a predetermined internal electrode 5 a having the same polarity is connected to one end face of the honeycomb structure portion 1. (7a) and the other external electrode 7 (7b) to which the remaining internal electrode 5b having the same polarity is connected, and the voltage is applied to one external electrode 7a and the other external electrode 7b. The pair of external electrodes 7 is preferable. Moreover, as shown in FIG. 4, the honeycomb structure part 1 has one external electrode (not shown) to which a predetermined internal electrode 5a having the same polarity is connected on one end face, and the other end face The other external electrode 7 (7b) to which the remaining internal electrodes 5b having the same polarity are connected may be provided. In this case, the voltage between one external electrode and the other external electrode 7b Is a pair of external electrodes 7 for applying. Here, FIG. 3 is a perspective view schematically showing another embodiment of the honeycomb-type piezoelectric / electrostrictive element of the present invention and showing a state in which an external electrode is disposed on one end face. FIG. 4 is a perspective view schematically showing another embodiment of the honeycomb-type piezoelectric / electrostrictive element of the present invention and showing a state in which external electrodes are disposed on both end faces (one end face is not shown). is there.

  The shape of the external electrode 7 is not particularly limited as long as it is connected to the internal electrode having the same polarity, but is preferably a linear (band-shaped) electrode disposed on the end face of the honeycomb structure portion 1. For example, as shown in FIG. 3, when internal electrodes (internal electrode 5a and internal electrode 5b) having different polarities are arranged alternately, a linear (band-like) electrode in which the internal electrodes 5a are connected in a diagonal direction. And the comb-shaped electrode formed by connecting the L-shaped electrodes arranged along the outer periphery of the end face of the honeycomb structure portion 1 as the external electrode 7a, and the internal electrodes 5b Are arranged in a diagonal direction so as to extend along the outer periphery of the end face of the honeycomb structure portion 1 (in a position not overlapping with the L-shaped electrode of the external electrode 7a). The external electrode 7b is preferably formed in a comb-like shape by connecting the (L) -shaped electrode. This is because even when both the external electrodes 7a and 7b are disposed on one end face of the honeycomb structure 1, the external electrode 7a is disposed on one end face of the honeycomb structure 1 and the external electrode 7b is disposed on the other end face. The same applies to the case where they are disposed. Further, the thickness of the external electrode 7 is not particularly limited and is preferably 0.1 to 20 μm.

  The material of the external electrode 7 is not particularly limited, but it is preferable that the external electrode 7 is made of a conductive metal that is solid at room temperature. For example, simple metals or alloys containing aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, etc. Can be mentioned.

  In addition, the external electrodes are not arranged directly on the honeycomb structure, but on the substrate, one external electrode corresponding to each of the predetermined internal electrodes having the same polarity and the remaining internal electrodes having the same polarity. A wiring board is formed by forming another external electrode corresponding to each of the electrodes, and the wiring board is electrically connected to one end face of the honeycomb structure portion with a predetermined internal electrode and a corresponding external electrode. The remaining internal electrodes and the corresponding external electrodes may be joined in an electrically connected state. Here, the one external electrode and the other external electrode are a pair of external electrodes for applying a voltage. For example, as shown in FIGS. 8A and 8B, the position of the substrate 31 in which the through hole 33 is formed in the position where the through hole 33 is formed at a position overlapping with each cell when arranged on the end face of the honeycomb structure 1. A wiring board 35 in which external electrodes are provided can be used. As shown in FIG. 9, the bonding surface 32 side (back side) external electrodes 41 a and 41 b and the surface 34 side external electrodes 42 a and 42 b are connected through the through-hole 33. 8A, 8B and 9, the bonding surface side external electrode 41a and the surface side external electrode 42a are portions that are electrically connected to predetermined internal electrodes of the honeycomb structure portion, and the bonding surface side external electrode 41b and The front side external electrode 42b is a portion that is electrically connected to the remaining internal electrodes of the honeycomb structure. Further, wiring from a power source or the like is connected to the extraction terminals 43a and 43b. FIG. 8A is a plan view seen from the bonding surface 32 side of the wiring board 35, and FIG. 8B is a plan view seen from the surface 34 (surface opposite to the bonding surface 32) side of the wiring board 35. FIG. 9 is a cross-sectional view perpendicular to the bonding surface of the wiring board 35.

  As the substrate 41, a known electric wiring substrate can be used. The thickness of the substrate 41 is preferably 0.1 to 3 mm. The size of the through hole 33 is not particularly limited, but is preferably smaller than the cross section of the corresponding cell of the honeycomb structure part.

  FIG. 10 schematically shows a part of the honeycomb type piezoelectric / electrostrictive element 100 in which the wiring substrate 35 provided with the external electrodes is attached to the honeycomb structure 1, and is a plane parallel to the axial direction of the honeycomb structure 1. It is sectional drawing cut | disconnected by. As shown in FIG. 10, the honeycomb structure portion 1 and the wiring substrate 35 on which the external electrodes are disposed include the cells 2 of the honeycomb structure portion 1 and the through holes 33 of the wiring substrate 35 corresponding to the respective cells 2. They are coupled so as to overlap (so that the cell 2 and the through hole 33 communicate with each other). The honeycomb structure portion 1 and the wiring substrate 35 are preferably bonded together by an adhesive 44. As the adhesive 44, an epoxy resin-based adhesive can be used, and glass or the like can be used when the wiring board is ceramics, and an epoxy resin-based adhesive is preferable. Known epoxy resin adhesives can be used. The adhesive 44 is preferably applied to the wiring board 35 by printing. A predetermined internal electrode 5a of the honeycomb structure part 1 and an external electrode disposed on the corresponding wiring board 35 are electrically connected, and the remaining internal electrode 5b of the honeycomb structure part 1 and the wiring board corresponding to each of them are electrically connected. In order to electrically connect the external electrode disposed in 35, as shown in FIG. 10, the through hole 33 in which the external electrode is disposed and the end of the cell 2 are filled with the conductive material 45, It is preferable to electrically connect the external electrode disposed on the wiring board 35 and the internal electrode disposed on the cell 2 through 45. The filling state of the conductive material 45 into the through-hole 33 and the end of the cell 2 is not particularly limited as long as the external electrode and the internal electrode can be electrically connected. For example, as shown in FIG. 10, the conductive material 45 is preferably filled so as to close the through-hole 33 and plug the end of the cell 2 (close the entire end of the cell 2). Further, the conductive material 45 may be filled in a state in which the through hole 33 and the end of the cell 2 are not completely blocked. The conductive material 45 is preferably made by press-fitting a conductive paste from the through-hole 33 and curing it. As the conductive paste, a silver paste or a copper paste containing an adhesive component that can be used by drying and curing at 200 ° C. or lower can be used, and a silver paste is preferable.

  The honeycomb-type piezoelectric / electrostrictive element of the present embodiment has a conductive plugging portion in contact with the internal electrode at one end of the cell, and one external electrode and the other external electrode are plugged. It is preferable that each of them is connected to a predetermined internal electrode and the remaining internal electrodes via a portion. When connecting the external electrode and the internal electrode, it is necessary to connect the external electrode to the internal electrode exposed at the end of the honeycomb structure part, but the area of the internal electrode exposed at the end of the honeycomb structure part is not necessarily It's not big. Therefore, by providing a conductive plugging portion at the end portion of the cell and connecting the external electrode and the internal electrode via the plugging portion, the end face of the plugging portion (the end portion of the honeycomb structure portion) It is possible to connect the external electrode using the entire surface exposed to (1). Although the depth of a plugging part is not specifically limited, 0.5-5 mm is preferable.

  Further, when one external electrode is disposed on one end face of the honeycomb structure portion and the other external electrode is disposed on the other end face, one external electrode of the cell in which the predetermined internal electrode is disposed At the end where the electrode is disposed, there is a conductive plugging portion in contact with the internal electrode, and the other external electrode of the cell where the remaining internal electrode is disposed is disposed. It is preferable to have a conductive plugging portion in contact with the internal electrode at the end on the other side. Here, the predetermined internal electrodes are internal electrodes having the same polarity, and the remaining internal electrodes are internal electrodes having the same polarity.

  The material of the conductive plugging portion is not particularly limited, and is preferably solid at room temperature and containing a conductive metal. For example, a simple metal or alloy containing aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, etc. Can be mentioned.

  The conductive plugging portion may be disposed so as to completely block the cell hole, or may be disposed so as to block a part of the cell hole. It may be dense or porous. In the case of a porous material, since there is air permeability between the inside and outside of the cell, there is an advantage that the reliability with respect to a change in pressure in the outside world is high. In the case of a dense material, there is an advantage that it is possible to exclude substances that adversely affect the durability of the element, such as moisture in the outside world.

  As shown in FIG. 5, the honeycomb-type piezoelectric / electrostrictive element 100 of the present embodiment has the plugging portions 11 at the end portions of the cells as described above, and further the external electrodes 7 ( 7a and 7b) are preferably provided with an insulating protective film 12 in a lattice shape so as to cover the partition walls and the internal electrodes and expose the plugging portions 11 along the partition walls. . The external electrode 7 (7a, 7b) is disposed on the surface of the insulating protective film 12, and is connected to the plugged portion 11 exposed from the opening 13 of the lattice-shaped insulating protective film 12. Is preferred. FIG. 5 is a perspective view schematically showing another embodiment of the honeycomb-type piezoelectric / electrostrictive element of the present invention.

  As described above, the insulating protective film 12 is disposed on the end face of the honeycomb structure portion 1 in a lattice shape so as to cover the partition walls and the internal electrodes and to expose the plugging portions 11. It becomes easier to connect only to the plugged portions having the same. In other words, if the insulating protective film 12 is not provided, even if only the plugging portion having the same polarity is connected by the external electrode, the distance from the adjacent plugging portion having another polarity is short. It may be in a state of being easily in contact with other plugging portions of polarity. In such a case, when the insulating protective film 12 is disposed in a lattice shape so as to cover the partition walls and the internal electrodes, the exposed portions of the plugging portions with other polarities become small and it becomes difficult to contact the external electrodes with different polarities. Therefore, it is preferable that the insulating protective film 12 covers not only the partition walls and the internal electrodes, but also the outer edge portion of the end face of the plugged portion inside thereof. At this time, it is preferable that the outer edge portion of the end face of the plugged portion is covered by 20 to 80% of the length of one side.

  The material of the insulating protective film 12 is not particularly limited as long as it is an electrically insulating material, and examples thereof include glass, crystallized glass, and resin.

  In another embodiment of the honeycomb-type piezoelectric / electrostrictive element of the present invention, one end face of the honeycomb structure portion has external electrodes that are independently connected to the respective internal electrodes, and independently through the external electrodes. A voltage can be applied to each internal electrode. The honeycomb type piezoelectric / electrostrictive element of the present embodiment is one embodiment of the honeycomb type piezoelectric / electrostrictive element of the present invention described above except that a voltage can be independently applied to each internal electrode. It is the same as the form. According to the honeycomb-type piezoelectric / electrostrictive element of the present embodiment, voltage application can be controlled for each internal electrode. For example, each of the cells is sequentially arranged at a predetermined time difference in one direction in each cell array. By applying a voltage to the internal electrode, as shown in FIG. 11, the end face 46 of the honeycomb type piezoelectric / electrostrictive element 100 fluctuates so as to wave, and this pulsation pumps the honeycomb type piezoelectric / electrostrictive element 100. Can be used. FIG. 11 is a side view illustrating a state where the end face 46 of the honeycomb type piezoelectric / electrostrictive element 100 is fluctuating. FIG. 11 shows the arrangement of the cells 47, and shows a state in which waves are formed in the direction in which the cells 47 are arranged (one direction in the arrangement) by sequentially expanding and contracting each cell.

  Further, according to the honeycomb type piezoelectric / electrostrictive element of the present embodiment, as shown in FIG. 12, a voltage is applied to each internal electrode so that the end face 46 undulates in the direction of rotation about the central portion. can do. As a result, the honeycomb-type piezoelectric / electrostrictive element of the present embodiment can be used as a rotary motor. FIG. 12 is a perspective view illustrating a state where the end face 46 of the honeycomb type piezoelectric / electrostrictive element 100 is undulated so as to rotate.

  Next, the manufacturing method of the honeycomb type piezoelectric / electrostrictive element of the present invention will be described. The honeycomb type piezoelectric / electrostrictive element of the present invention can be manufactured by, for example, the following method, but the method of manufacturing the honeycomb type piezoelectric / electrostrictive element of the present invention is limited to the following method. There is nothing. Here, as shown in FIG. 5, a plugged portion 11, an insulating protective film 12, and two external electrodes 7 (7a, 7b) having different polarities are disposed on one end face of the honeycomb structure portion 1. A method for manufacturing the honeycomb type piezoelectric / electrostrictive element 100 will be described.

  First, a clay for forming the honeycomb structure 1 is formed. This is to use the raw materials mentioned above as the material of the partition walls 3 of the honeycomb structure 1 and mix and knead the raw materials to form a clay. For example, water, a dispersion medium such as an organic solvent, an organic binder, a dispersant, and the like are added to a powder raw material such as lead zirconate titanate to form a forming raw material, which is kneaded to form a clay-like clay.

  As the organic binder, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol and the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  As the dispersant, ethylene glycol, dextrin, fatty acid soap, polyalcohol and the like can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type.

  When an organic solvent is used as the dispersion medium, it is preferable to use an organic solvent such as alcohol. As the organic solvent, for example, terpineol can be used. In this case, polyvinyl butyral can also be used as the organic binder.

  There is no restriction | limiting in particular as a method of knead | mixing a shaping | molding raw material and preparing a clay, For example, the method of using a kneader, a vacuum clay kneader, etc. can be mentioned.

  Next, the obtained clay is formed into a honeycomb shape to produce a honeycomb formed body. There is no restriction | limiting in particular as a method of producing a honeycomb molded object, Conventionally well-known shaping | molding methods, such as extrusion molding, injection molding, and press molding, can be used. Among them, a preferable example is a method of extruding the clay prepared as described above using a die having a desired cell shape, partition wall thickness, and cell density.

  Further, a slurry in which a raw material and an organic solvent containing a binder are mixed is prepared and molded by a doctor blade method or the like, and a plurality of through holes 22 for forming a cell as shown in FIG. 7A are provided. The green sheet 21 may be produced, and the resulting green sheet 21 may be laminated as shown in FIG. 7B to produce the honeycomb formed body 23. 7A and 7B schematically show a process of manufacturing a honeycomb structure part constituting the honeycomb type piezoelectric / electrostrictive element of the present invention, FIG. 7A is a perspective view showing a green sheet, and FIG. It is a perspective view which shows the state which laminated | stacked the sheet | seat.

  Next, it is preferable to produce a honeycomb dried body by drying the obtained honeycomb formed body. The drying method is not particularly limited, and conventionally known drying methods such as hot air drying, microwave drying, dielectric drying, reduced pressure drying, vacuum drying, freeze drying and the like can be used. Especially, the drying method which combined hot air drying, microwave drying, or dielectric drying is preferable at the point which can dry the whole molded object rapidly and uniformly.

  Next, the obtained honeycomb dried body may be calcined before main firing to produce a calcined body. “Preliminary firing” means an operation of burning and removing organic substances (organic binder, dispersant, etc.) in the honeycomb formed body. The calcining temperature may be about 200 to 800 ° C. Although there is no restriction | limiting in particular as a calcination time, Usually, it is about 10 to 100 hours.

  Next, by firing (main firing) the obtained calcined body, a honeycomb structure portion 1 as shown in FIG. 6A can be obtained. “Main firing” means an operation for sintering and densifying the forming raw material in the calcined body to ensure a predetermined strength. Since the firing conditions (temperature and time) vary depending on the type of molding raw material, appropriate conditions may be selected according to the type. 6A to 6E are front views schematically showing a manufacturing process in one embodiment of the method for manufacturing a honeycomb-type piezoelectric / electrostrictive element of the present invention and viewed from one end face side of the honeycomb structure part.

  Next, as shown in FIG. 6B, the internal electrode 5 is disposed on the inner wall surface 4 of the cell 2 of the honeycomb structure portion 1 so as to cover the entire inner wall surface 4. The location of the internal electrode 5 is preferably the entire inner wall surface 4, but may be a part of the inner wall surface 4. As the internal electrode 5, the above-described materials such as silver and copper can be used. Although the arrangement | positioning method of the internal electrode 5 is not specifically limited, For example, it can arrange | position with the following method. First, the metal used as the material of the internal electrode 5 is powdered, and a solvent such as alcohol or an organic binder is added to form a slurry. The slurry concentration is preferably 50 to 80% by mass. Moreover, as a viscosity of a slurry, 0.05-50 Pa.s is preferable. And the honeycomb structure part 1 is immersed in the slurry, the slurry is attached to the inner wall surface 4 of the cell 2, and then heated at 600 to 900 ° C., thereby forming a film-like internal electrode so as to cover the entire inner wall surface 4. 5 may be provided. In this case, when the slurry is attached to the inner wall surface 4 of the cell 2, it is preferable that the slurry is efficiently attached to the inner wall surface 4 of the cell 2 by sucking from the partition wall side. Further, a mask may be applied to the outer periphery of the honeycomb structure portion 1 or the partition wall portion of the end surface so that the slurry does not adhere to portions other than the inner wall surface of the cell.

  In addition to the above methods, plating, sputtering and the like are also used. It is preferable to polish the end face slightly so that the internal electrode 5 disposed on the inner wall surface 4 of the adjacent cell 2 does not conduct so that the ceramic portion is exposed at the end face of the partition wall.

  Next, as shown in FIG. 6C, it is preferable to dispose a plugging portion 11 on one end face of the honeycomb structure portion 1 in which the internal electrode 5 is disposed. The method for disposing the plugging portion 11 is not particularly limited. For example, when two external electrodes having different polarities are disposed at one end of the honeycomb structure portion, first, the plugging portion 11 is disposed in the plugging portion. A plugging slurry (or plugging paste) containing a metal raw material powder, an organic solvent such as water or alcohol, and an organic binder is stored in a storage container. The slurry concentration is preferably 50 to 90% by mass. The viscosity of the slurry is preferably 5 to 5000 Pa · s. Then, one end portion of the honeycomb structure portion 1 provided with the internal electrode 5 is immersed in a storage container, and the plugging slurry is filled in the opening portion of the cell 2 to form the plugging portion 11. To do. In addition, when one external electrode is disposed at one end of the honeycomb structure portion and another external electrode having a different polarity is disposed at the other end portion, among the cells at each end portion, A mask is applied to a cell in which an internal electrode not connected to an external electrode is provided, and the plugging slurry is filled in the opening of the cell 2 at both ends by the above method to form the plugged portion 11. Is preferred. Although the depth which arrange | positions a plugging part is not specifically limited, 0.5-5 mm is preferable. In addition, when one external electrode is disposed at one end of the honeycomb structure and another external electrode having a different polarity is disposed at the other end, the above mask is used from the viewpoint of improving workability. The plugging portions 11 may be disposed in the opening portions of all the cells at both ends of the honeycomb structure portion without performing the above.

  Next, as shown in FIG. 6D, the partition wall 3 (see FIG. 6C) and the internal electrode 5 (see FIG. 6C) are formed along the partition wall 3 (see FIG. 6C) on the end surface of the honeycomb structure 1 where the plugging portions 11 are disposed. It is preferable to dispose the insulating protective film 12 in a lattice shape so as to cover the plugged portion 11 and to cover the plugged portion 11 (see FIG. 6C). The method for disposing the insulating protective film 12 is not particularly limited, but it is preferable to dispose the insulating protective film 12 by printing the material having electrical insulation properties on the end face of the honeycomb structure 1. Other methods include stamping sheet adhesion, brush coating, plating, and sputtering.

  Next, as shown in FIG. 6E, the external electrode 7 (7a, 7b) is disposed on the surface of the insulating protective film 12, and connected to the plugging portion 11 having the same polarity exposed from the opening portion 13. The piezoelectric / electrostrictive element 100 is preferable. Here, the “plugged portion having the same polarity” refers to a plugged portion that contacts the internal electrode having the same polarity. The arrangement method of the external electrodes 7 (7a, 7b) is not particularly limited, but a material that can be used as the material of the external electrodes 7 is sealed with the same surface and polarity of the insulating protective film 12 on the end face of the honeycomb structure portion 1. It is preferable to arrange by printing on the surface of the stopper. Other methods include stamping sheet adhesion, brush coating, plating, and sputtering. In the honeycomb type piezoelectric / electrostrictive element shown in FIG. 6E, plugging portions (internal electrodes) having different polarities are alternately arranged. Similarly, when one of the external electrodes 7 (7a, 7b) is disposed at one end of the honeycomb structure portion and the other is disposed at the other end portion of the honeycomb structure portion, the predetermined position is similarly determined. It is preferable to arrange by printing or the like.

  As shown in FIG. 6E, a pair of external electrodes may be arranged in one honeycomb structure part to form a honeycomb type piezoelectric / electrostrictive element. However, a honeycomb structure capable of cutting out a plurality of honeycomb structure parts is manufactured. Then, a plurality of pairs (a plurality of pairs) of external electrodes as shown in FIG. 6E were formed on the end face of the honeycomb structure, and then the honeycomb structure was cut to provide a pair of external electrodes. A plurality of honeycomb-type piezoelectric / electrostrictive elements may be produced. In addition, after the honeycomb structure is manufactured, a plurality of honeycomb structure portions may be cut out, and then an internal electrode, a plugging portion, an insulating protective film, and an external electrode may be provided. Further, the honeycomb structure portion may be appropriately processed in the manufacturing process of the honeycomb type piezoelectric / electrostrictive element.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1
(Preparation of molding raw materials)
PMO (lead magnesium niobate) 15 mol%, PT (lead titanate) 45 mol%, PZ (lead zirconate) 40 mol% of the main component consisting of component ratio, NiO to 100 parts by mass of this powder raw material A ceramic synthetic powder material (piezoelectric powder) to which 0.5 parts by mass of (nickel oxide) was added was obtained. The average particle size of the obtained piezoelectric powder was 0.5 μm. The average particle size was measured using a dynamic light scattering photometer DSL7000 manufactured by Otsuka Electronics Co., Ltd. To this, methylcellulose was blended as a binder, ethylene glycol was blended as a plasticizer, and water was blended appropriately to obtain a clay-like molding raw material.

(Molding)
The obtained forming raw material was extruded to obtain a honeycomb formed body. The die size was a honeycomb shape with a wall thickness of 50 μm and a pitch of 400 μm. The area of the die was about 10 × 10 mm (the number of cells was 25 × 25). The obtained honeycomb formed body was cut to a length of about 40 mm.

(Baking)
The obtained honeycomb formed body was degreased at 600 ° C. in the air for 5 hours, and then fired in a sealed sheath at 1250 ° C. for 2 hours. At this time, 5 g of piezoelectric powder having the same composition as the above piezoelectric powder was placed on the bottom in a 10 × 10 × 8 cm sheath, covered, and fired in a sealed state. The obtained honeycomb was densely sintered, and a honeycomb-shaped sintered body (honeycomb structure portion) having a wall thickness of 40 μm and a pitch of 320 μm was obtained.

(Formation of internal electrodes)
The obtained honeycomb sintered body (honeycomb structure part) was completely immersed in a low-viscosity silver (Ag) slurry (viscosity: 0.05 to 0.1 Pa · s) and coated on the cell wall surface. After drying, a silver (Ag) internal electrode was formed on the inner wall surface of the cell by heat treatment at 700 ° C. using a belt furnace. The obtained sample was cut out so that the number of cells was 20 × 20.

(Plugged part)
On one end face, a highly viscous silver (Ag) paste (viscosity: 300 to 500 Pa · s) was immersed to a depth of about 2 mm, dried and fired to form a plugged portion. As the silver paste, silver powder added with terpineol and polyvinyl butyral was used. In addition, the end face was lightly polished so that the silver (Ag) internal electrode disposed on the inner wall surface of the adjacent cell was not conductive, so that the ceramic portion was exposed on the end face of the partition wall. Further, the other end face was cut so that the element length (length in the central axis direction) was 32 mm.

(Insulating protective film)
A grid-like insulating protective film was disposed on the end face where the plugged portion was formed. An insulating glass paste was used to form the insulating protective film. The insulating glass paste was printed on the end face of the honeycomb structure portion with the same pitch width as the partition walls so as to cover the end faces of the partition walls and the end portions of the internal electrodes. At this time, the line width was set to 200 μm, and the end face of the silver (Ag) plugging portion disposed in each cell was exposed to about 150 × 150 μm.

(External electrode)
A pair of silver (Ag) external electrodes is printed and formed in a comb-like shape on the end face of the honeycomb structure portion where the plugging portion and the insulating protective film are disposed so that each line extends diagonally. Wiring was performed so that a voltage was applied to cells adjacent to each other to obtain a honeycomb-type piezoelectric / electrostrictive element. Furthermore, a lead wire was wired to each external electrode.

(Characteristic evaluation)
When a displacement amount when a voltage of 200 V was applied to the pair of external electrodes was measured with a laser displacement meter, a displacement (contraction deformation amount) of 45 μm in the central axis direction was confirmed. When the generated force (blocking force) was estimated, it was about 1000 N (Newton). A displacement equivalent to that of a laminated actuator consisting of the same size and electric capacity could be secured. In addition, no element destruction or characteristic deterioration was observed after 100 million cycles.

(Example 2)
(Preparation of forming raw materials-formation of internal electrodes)
From the preparation of the forming raw material to the formation of the internal electrode, a honeycomb sintered body (honeycomb structure portion) in which the internal electrode was formed was produced in the same manner as in Example 1.

(Wiring board)
The wiring board shown in FIGS. 8A, 8B and 9 was produced. A glass epoxy substrate was used as the substrate, and 20 × 20 through-holes having a diameter of 0.15 mm were formed at intervals of 0.32 mm in the substrate. And the joining surface side external electrode, the surface side external electrode, and the extraction terminal were formed so that it might connect within a through-hole. The external electrode and the extraction terminal were formed by a method of pattern formation by etching a copper printed board, formation of a through hole by a drill, and copper plating in the through hole.

(Bonding of honeycomb sintered body and wiring board)
The honeycomb sintered body and the wiring board were joined so that the internal electrode and the external electrode were electrically connected to obtain a honeycomb type piezoelectric / electrostrictive element. Specifically, an epoxy resin adhesive was applied to the wiring board by printing. As shown in FIG. 10, the honeycomb sintered body (honeycomb structure portion 1) and the wiring board 35 were joined together with an epoxy resin adhesive. Thereafter, the silver paste was press-fitted from the through hole 33 with a syringe, and the external electrode and the internal electrode were electrically connected by filling the through hole and the cell end with the silver paste. Furthermore, a lead wire was wired to the takeout terminal.

(Characteristic evaluation)
When the amount of displacement when a voltage of 200 V was applied to the pair of external electrodes was measured with a laser displacement meter, the same result as in Example 1 could be obtained.

  The present invention is suitable as an actuator element such as an opening / closing actuator or a precision positioning actuator of a fuel injection valve of a diesel engine, and as a sensor element for various sensors such as an ultrasonic sensor, an acceleration sensor, an angular velocity sensor, an impact sensor, and a mass sensor. Can be used.

1 is a perspective view schematically showing one embodiment of a honeycomb type piezoelectric / electrostrictive element of the present invention. It is the perspective view which cut out and expanded the part A of FIG. 1A. FIG. 5 is an enlarged cross-sectional view schematically showing a part of a cross section perpendicular to a central axis of a honeycomb structure part constituting another embodiment of the honeycomb type piezoelectric / electrostrictive element of the present invention. FIG. 6 is a perspective view schematically showing another embodiment of the honeycomb type piezoelectric / electrostrictive element of the present invention and showing a state in which an external electrode is disposed on one end face. FIG. 6 is a perspective view schematically showing another embodiment of the honeycomb-type piezoelectric / electrostrictive element of the present invention and showing a state in which external electrodes are disposed on both end faces (one end face is not shown). It is a perspective view which shows typically other embodiment of the honeycomb type piezoelectric / electrostrictive element of this invention. FIG. 3 is a front view schematically showing a manufacturing process in one embodiment of a method for manufacturing a honeycomb-type piezoelectric / electrostrictive element of the present invention, as viewed from one end face side of a honeycomb structure part. FIG. 3 is a front view schematically showing a manufacturing process in one embodiment of a method for manufacturing a honeycomb-type piezoelectric / electrostrictive element of the present invention, as viewed from one end face side of a honeycomb structure part. FIG. 3 is a front view schematically showing a manufacturing process in one embodiment of a method for manufacturing a honeycomb-type piezoelectric / electrostrictive element of the present invention, as viewed from one end face side of a honeycomb structure part. FIG. 3 is a front view schematically showing a manufacturing process in one embodiment of a method for manufacturing a honeycomb-type piezoelectric / electrostrictive element of the present invention, as viewed from one end face side of a honeycomb structure part. FIG. 3 is a front view schematically showing a manufacturing process in one embodiment of a method for manufacturing a honeycomb-type piezoelectric / electrostrictive element of the present invention, as viewed from one end face side of a honeycomb structure part. It is a perspective view which shows typically the green sheet in the process of producing the honeycomb structure part which comprises the honeycomb type piezoelectric / electrostrictive element of this invention. FIG. 3 is a perspective view schematically showing a state in which green sheets are laminated in the process of manufacturing a honeycomb structure part constituting the honeycomb type piezoelectric / electrostrictive element of the present invention. It is the top view which looked at the wiring board from the joint surface side. It is the top view which looked at the wiring board from the surface side. It is sectional drawing perpendicular | vertical to the joint surface of a wiring board. FIG. 5 is a cross-sectional view schematically showing a part of another embodiment of the honeycomb-type piezoelectric / electrostrictive element of the present invention, cut along a plane parallel to the axial direction of the honeycomb structure portion. It is a side view explaining the state which the end surface part of other embodiment of the honey-comb type piezoelectric / electrostrictive element of this invention fluctuates in a wave shape. It is a perspective view explaining the state which the end surface part of other embodiment of the honey-comb type piezoelectric / electrostrictive element of this invention wavy so that it may rotate.

Explanation of symbols

1: honeycomb structure, 2: cell, 2a: corner, 3: partition, 4: inner wall surface, 5, 5a, 5b: internal electrode, 6: outer peripheral wall, 7, 7a, 7b: external electrode, 11: eye Sealing part, 12: insulating protective film, 13: opening portion, 21: green sheet, 22: through-hole, 23: honeycomb formed body, 31: substrate, 32: bonding surface, 33: through-hole, 34: surface, 35 : Wiring board, 41a, 41b: bonding surface side external electrode, 42a, 42b: surface side external electrode, 43a, 43b: take-out terminal, 44: adhesive, 45: conductive material, 46: end face, 47: cell, 100: Honeycomb type piezoelectric / electrostrictive element, A: portion, a1, a2, a3, a4, a5, a6, a7, a8: arrows.

Claims (10)

A honeycomb structure part having partition walls for partitioning a plurality of cells penetrating in the axial direction;
The inner wall surface of the cell includes an electrode (internal electrode) disposed so as to cover the entire inner wall surface from the inside,
The partition is a piezoelectric / electrostrictive body,
It is possible to deform the honeycomb structure portion by applying a voltage between the electrodes arranged in adjacent cells across the partition wall ,
One end face of the honeycomb structure part has one external electrode connected to a predetermined internal electrode having the same polarity, and another external electrode connected to the remaining internal electrode having the same polarity A honeycomb type piezoelectric / electrostrictive element , wherein the one external electrode and the other external electrode are a pair of external electrodes for applying a voltage .   The honeycomb-type piezoelectric / electrostrictive element according to claim 1, wherein the internal electrode is disposed in all the cells, and a voltage can be applied between all the cells adjacent to each other with the partition interposed therebetween. One end of the cell has a conductive plugging portion in contact with the internal electrode, and the one external electrode and the other external electrode are connected to the predetermined internal electrode via the plugging portion. The honeycomb-type piezoelectric / electrostrictive element according to claim 1 or 2 , wherein the honeycomb-type piezoelectric / electrostrictive element is connected to each of the remaining internal electrodes. On the end surface of the honeycomb structure portion where the external electrodes are disposed, an insulating protective film is disposed in a lattice shape along the partition walls so as to cover the partition walls and the internal electrodes and expose the plugging portions. And
The honeycomb-type piezoelectric / electrode according to claim 3 , wherein the external electrode is disposed on a surface of the insulating protective film and connected to the plugging portion exposed from an opening of the lattice-shaped insulating protective film. Electrostrictive element. The honeycomb-type piezoelectric / electrostrictive according to any one of claims 1 to 4 , wherein predetermined internal electrodes having the same polarity and remaining internal electrodes having the same polarity are alternately arranged. element. The honeycomb-type piezoelectric / electrostrictive element according to any one of claims 1 to 5 , wherein a cross-sectional shape perpendicular to the longitudinal direction of the cell is a quadrangle with arcuate corners. The honeycomb-type piezoelectric / electrostrictive element according to any one of claims 1 to 6 , wherein the partition wall has a thickness of 20 to 500 µm. The honeycomb-type piezoelectric / electrostrictive according to any one of claims 1 to 7 , wherein the honeycomb structure part is formed by firing an extrusion-molded raw material mainly composed of a piezoelectric / electrostrictive material. element. The honeycomb type piezoelectric / electrostrictive element according to any one of claims 1 to 8 , wherein the honeycomb structure part is formed by firing a laminate of green sheets mainly composed of a piezoelectric / electrostrictive material. The honeycomb-type piezoelectric / electrostrictive element according to any one of claims 1 to 9 , wherein the internal electrode has a thickness of 0.05 to 5 µm.

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