Piezoelectric ceramic stack

Abstract

The utility model discloses a piezoelectric ceramic stack, which comprises an electrode assembly, the electrode assembly comprises a plurality of electrode parts which are sequentially overlapped along a first direction, each electrode part comprises a piezoelectric ceramic piece and a metal piece, the metal piece is provided with a through hole, and the through hole is filled with glue; after the adjacent electrode parts are overlapped, the two sides of the metal sheet are attached to the side walls of the piezoelectric ceramic pieces of the adjacent electrode parts respectively, and the piezoelectric ceramic pieces of the adjacent electrode parts are bonded through glue. The metal sheet is attached to the piezoelectric ceramic piece, the electric connection effect is improved, and the influence of the glue layer on the piezoelectric ceramic stack rigidity is avoided. Moreover, when the glue in the through hole is cured, the side surface of the piezoelectric ceramic stack does not generate tensile stress, so that the side surface of the piezoelectric ceramic stack is prevented from generating cracks, and the reliability of the piezoelectric ceramic stack is improved. And finally, the influence of the thickness of the glue on the overall thickness of the piezoelectric ceramic stack can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of piezoelectric ceramics, in particular to a piezoelectric ceramic stack. Background Art

[0002] High-drive voltage piezoelectric ceramic stacks have the characteristics of high output, fast response speed, and long service life. Their drive voltage can reach 1000 volts and are mainly used in industrial and scientific research fields, such as high-load positioning, precision machining, high-speed switching, and active / adaptive optics. Unlike multilayer piezoelectric ceramic stacks with multiple layers of internal electrodes, high-drive voltage piezoelectric ceramic stacks are made of multiple separate ceramic monoliths bonded together.

[0003] In the prior art, surface electrodes are prepared on both sides of a single ceramic sheet by a silvering process, and then ceramic sheet, glue layer, metal sheet layer, glue layer, ceramic sheet layer, glue layer, metal sheet layer, etc. are stacked one on another in the order of ceramic sheet, glue layer, metal sheet layer, etc., and then the glue is cured to obtain a stack. The glue layer plays a role of bonding and fixing, and the metal sheet layer plays a role of connecting the surface electrodes of the ceramic sheet. However, since the glue layer is arranged between the metal layer and the surface electrode of the ceramic sheet, the electrical connection effect between the metal layer and the surface electrode of the ceramic sheet is reduced, and the energy conversion effect of the stack is further reduced; moreover, the entire glue layer will also limit the deformation of the stack, generate tensile stress on the side of the stack, and cause cracks to easily occur on the side of the stack; furthermore, during the curing stage of multiple glue layers, the volume of the glue will change, resulting in uncontrollable thickness of the glue layer, and ultimately making the height of the stack difficult to control.

[0004] Based on this, there is an urgent need for a piezoelectric ceramic stack to solve the above-mentioned problems. Utility Model Content

[0005] Based on the above, the purpose of the utility model is to provide a piezoelectric ceramic stack, improve the electrical connection effect, improve the reliability of the piezoelectric ceramic stack, and avoid the thickness of the glue affecting the overall thickness of the piezoelectric ceramic stack.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A piezoelectric ceramic stack comprises an electrode assembly, wherein the electrode assembly comprises a plurality of electrode components stacked in sequence along a first direction, wherein the electrode components comprise a piezoelectric ceramic sheet and a metal sheet, wherein the metal sheet is provided with a through hole, and wherein the through hole is filled with glue; after adjacent electrode components are stacked, two sides of the metal sheet are respectively adhered to the side walls of the piezoelectric ceramic sheet of the adjacent electrode component, and the piezoelectric ceramic sheets of the adjacent electrode components are bonded by the glue.

[0008] As a preferred technical solution for a piezoelectric ceramic stack, the metal sheet is arranged at the center of the piezoelectric ceramic sheet, and the diameter of the metal sheet is smaller than the diameter of the piezoelectric ceramic sheet.

[0009] As a preferred technical solution for a piezoelectric ceramic stack, electrode layers are provided on both sides of the piezoelectric ceramic sheet along the first direction, the electrode layers are attached to the metal sheet, and the diameter of the metal sheet is greater than the diameter of the electrode layers.

[0010] As a preferred technical solution for a piezoelectric ceramic stack, the metal sheet is provided with a lead-out end, the lead-out end of the 2Nth metal sheet along the first direction is connected to the first circuit, and the lead-out end of the 2N-1th metal sheet along the first direction is connected to the second circuit, and N is a positive integer.

[0011] As a preferred technical solution for a piezoelectric ceramic stack, projections of center lines of lead ends of adjacent metal sheets along the first direction are arranged at an angle.

[0012] As a preferred technical solution of a piezoelectric ceramic stack, the piezoelectric ceramic stack further includes an upper cover plate and a lower cover plate, and the upper cover plate and the lower cover plate are connected to two ends of the electrode assembly along the first direction.

[0013] As a preferred technical solution of a piezoelectric ceramic stack, the upper cover is attached to the metal sheet of the electrode component close to one end of the upper cover, and the upper cover is bonded to the glue; and / or

[0014] The lower cover plate is attached to the metal sheet of the electrode component close to one end of the lower cover plate, and the lower cover plate is bonded to the glue.

[0015] As a preferred technical solution for a piezoelectric ceramic stack, the upper cover plate and the lower cover plate are made of ceramic.

[0016] As a preferred technical solution for a piezoelectric ceramic stack, the outer wall of the piezoelectric ceramic stack is coated with a protective paint.

[0017] As a preferred technical solution for a piezoelectric ceramic stack, there are a plurality of through holes, and the plurality of through holes are evenly arranged on the metal sheet.

[0018] The beneficial effects of the utility model are:

[0019] The utility model provides a piezoelectric ceramic stack, in which a metal sheet is attached to a piezoelectric ceramic sheet, so that the metal layer and the piezoelectric ceramic sheet are directly connected, ensuring that the two are electrically connected, improving the electrical connection effect, and avoiding the influence of the glue layer on the rigidity of the piezoelectric ceramic stack. Furthermore, when the glue in the through hole is solidified, the side wall of the through hole can restrain the glue, ensuring that the glue will not be filled on the side of the piezoelectric ceramic stack, and the side of the piezoelectric ceramic stack will not produce tensile stress, avoiding cracks on the side of the piezoelectric ceramic stack, thereby improving the reliability of the piezoelectric ceramic stack. Finally, since the thickness of the metal layer is controllable, the amount of glue in each through hole is adaptively adjusted according to demand, so that the thickness of the glue can be avoided from affecting the overall thickness of the piezoelectric ceramic stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0021] Figure 1 It is a structural exploded diagram of a piezoelectric ceramic stack provided in a specific embodiment of the utility model;

[0022] Figure 2 It is a front view of a piezoelectric ceramic stack provided by a specific embodiment of the utility model;

[0023] Figure 3 It is a top view of a piezoelectric ceramic stack provided by a specific embodiment of the utility model.

[0024] The following are marked in the figure:

[0025] 1. electrode component; 11. piezoelectric ceramic sheet; 111. electrode layer; 12. metal sheet; 121. through hole; 122. lead end; 13. glue;

[0026] 2. Upper cover;

[0027] 3. Lower cover. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0029] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0031] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0032] like Figure 1 and Figure 2 As shown, this embodiment provides a piezoelectric ceramic stack, which includes an electrode assembly, the electrode assembly includes a plurality of electrode components 1 stacked in sequence along a first direction, the electrode component 1 includes a piezoelectric ceramic sheet 11 and a metal sheet 12, the metal sheet 12 is provided with a through hole 121, and the through hole 121 is filled with glue 13; after the adjacent electrode components 1 are stacked, the two sides of the metal sheet 12 are respectively attached to the side walls of the piezoelectric ceramic sheet 11 of the adjacent electrode component 1, and the piezoelectric ceramic sheets 11 of the adjacent electrode components 1 are bonded by the glue 13. In this embodiment, the glue 13 is a two-component epoxy glue, and the metal sheet 12 is a copper oxide sheet.

[0033] Among them, the metal sheet 12 is attached to the piezoelectric ceramic sheet 11, so that the metal layer is directly connected to the piezoelectric ceramic sheet 11, ensuring that the two are electrically connected, improving the electrical connection effect, and avoiding the influence of the glue layer on the rigidity of the piezoelectric ceramic stack. Furthermore, when the glue 13 in the through hole 121 is solidified, the side wall of the through hole 121 can constrain the glue 13, ensuring that the glue 13 will not be filled on the side of the piezoelectric ceramic stack, and the side of the piezoelectric ceramic stack will not produce tensile stress, avoiding cracks on the side of the piezoelectric ceramic stack, thereby improving the reliability of the piezoelectric ceramic stack. Finally, since the thickness of the metal layer is controllable, the amount of glue 13 in each through hole 121 is adaptively adjusted according to demand, so that the thickness of the glue 13 can be avoided from affecting the overall thickness of the piezoelectric ceramic stack.

[0034] Preferably, if Figure 1 and Figure 3 As shown, there are multiple through holes 121, and the multiple through holes 121 are evenly arranged on the metal sheet 12. The glue 13 forms multiple glue columns in the multiple through holes 121, thereby improving the connection strength of adjacent piezoelectric ceramic sheets 11, and changing the glue layer of the prior art into a local glue column, so that the metal layer is directly connected to the surface of the piezoelectric ceramic sheet 11, which fully ensures the electrical connection between the two and avoids the influence of the glue layer on the stiffness of the piezoelectric ceramic stack.

[0035] Preferably, the metal sheet 12 is disposed at the center of the piezoelectric ceramic sheet 11, and the diameter of the metal sheet 12 is smaller than the diameter of the piezoelectric ceramic sheet 11. This prevents sparking, arcing, and other undesirable conditions from occurring between adjacent positive and negative electrodes when the piezoelectric ceramic stack is driven by a large voltage during operation.

[0036] Further preferably, the piezoelectric ceramic sheet 11 is provided with an electrode layer 111 on both sides along the first direction, the electrode layer 111 is attached to the metal sheet 12, and the diameter of the metal sheet 12 is larger than the diameter of the electrode layer 111. Among them, the areas where the electrode layer 111 on the upper and lower surfaces of the piezoelectric ceramic sheet 11 are opposite are active areas, and the areas without the electrode layer 111 are inactive areas. When power is turned on, the active area will deform, generating stress on the inactive area, and since the size of the metal sheet 12 is smaller than the size of the piezoelectric ceramic sheet 11, and the size of the electrode layer 111 is smaller than the size of the metal sheet 12, there are tiny gaps at the edges of adjacent piezoelectric ceramic sheets 11, which is convenient for stress release and helps to extend the service life of the piezoelectric ceramic stack.

[0037] Furthermore, if Figure 1-Figure 3As shown, the metal sheet 12 is provided with a lead-out terminal 122, the lead-out terminal 122 of the 2Nth metal sheet 12 along the first direction is connected to the first circuit, and the lead-out terminal 122 of the 2N-1th metal sheet 12 along the first direction is connected to the second circuit, where N is a positive integer. The first circuit connects the lead-out terminal 122 of the 2Nth metal sheet 12 in series to form a positive electrode, and the second circuit connects the lead-out terminal 122 of the 2N-1th metal sheet 12 in series to form a negative electrode, meeting the electrical requirements.

[0038] Further preferably, the projections of the center lines of the lead ends 122 of the adjacent metal sheets 12 along the first direction are arranged at an angle. In order to facilitate the connection of the positive electrode and the negative electrode of the piezoelectric ceramic stack, in this embodiment, the projections of the center lines of the lead ends 122 of the adjacent metal sheets 12 along the first direction are at an angle of 180°, and the first circuit and the second circuit can be wires or copper foils, and the lead ends 122 of the metal sheets 12 on the same side are connected in series using wires or copper foils, thereby increasing the convenience of operation.

[0039] Furthermore, the piezoelectric ceramic stack further includes an upper cover plate 2 and a lower cover plate 3, which are connected to both ends of the electrode assembly along the first direction. The upper cover plate 2 and the lower cover plate 3 can protect both ends of the piezoelectric ceramic stack. In this embodiment, the material of the upper cover plate 2 and the lower cover plate 3 is ceramic, such as alumina, aluminum nitride, etc., to improve the structural strength.

[0040] In this embodiment, the upper cover plate 2 is attached to the metal sheet 12 of the electrode component 1 near one end of the upper cover plate 2, and the upper cover plate 2 is bonded to the glue 13; and / or the lower cover plate 3 is attached to the metal sheet 12 of the electrode component 1 near one end of the lower cover plate 3, and the lower cover plate 3 is bonded to the glue 13, thereby realizing the assembly connection between the upper cover plate 2 and the lower cover plate 3 and the electrode assembly.

[0041] Preferably, the outer wall of the piezoelectric ceramic stack is coated with a protective paint. The protective paint can be a three-proof paint, which has good high and low temperature resistance; after curing, it forms a transparent protective film with excellent insulation, moisture-proof, leakage-proof, shock-proof, dust-proof, corrosion-proof, aging-proof, corona-resistant and other properties.

[0042] This embodiment also provides a method for processing the piezoelectric ceramic stack, which is as follows:

[0043] Using a double-end grinder known in the industry, the piezoelectric ceramic sheet 11 with a diameter of 10 mm is ground into a single sheet with a thickness of 0.5 mm ± 5 um; using the silvering process known in the industry, silver paste is printed on the upper and lower surfaces of the piezoelectric ceramic sheet 11 by screen printing, dried at 80°C, and sintered at 850°C in a box furnace. After sintering, the diameter of the surface silver layer is about 9.5 mm and the thickness is about 5 um, forming an electrode layer 111. Using the oil bath polarization method known in the industry, a DC power supply is used to apply a field strength of 4 kv / mm to each piezoelectric ceramic sheet 11 in 130°C silicone oil for 15 minutes. The thickness of the upper cover plate 2 and the lower cover plate 3 is 1 mm, and the diameter is consistent with the piezoelectric ceramic sheet 11. The main body of the metal sheet 12 has a diameter of 9.8 mm and a thickness of 0.05 mm. The metal sheet 12 has 19 through holes 121 with a diameter of 1 mm. The lead-out end 122 extends about 2 mm beyond the edge of the piezoelectric ceramic sheet 11 .

[0044] During assembly, the lower cover plate 3 is laid flat, and then the metal sheet 12 is placed parallel to the lower cover plate 3, and is placed in the middle area as far as possible; then a two-component epoxy glue is dripped on each through hole 121 of the metal sheet 12 using a glue dispenser, and the amount of glue 13 applied is consistent with the volume of the through hole 121; then the first piezoelectric ceramic sheet 11 is placed; then the second metal sheet 12 is placed parallel to it, and it is noted that the lead-out end 122 of the second metal sheet 12 is 180° different from the lead-out end 122 of the first metal sheet 12 in the horizontal direction, in order to separate Connect the positive and negative electrodes of the piezoelectric ceramic stack separately; then follow the same glue dispensing operation to drip two-component epoxy glue on each through hole 121 of the second metal sheet 12; then place the second piezoelectric ceramic sheet 11; then place the third metal sheet 12, the direction of its lead end 122 is consistent with the direction of the lead end 122 of the first metal sheet 12, and dispense glue; then place the third piezoelectric ceramic sheet 11; then place the fourth metal sheet 12, the direction of its lead end 122 is consistent with the direction of the lead end 122 of the second metal sheet 12. And so on, until the last metal sheet 12 is placed, glue is dispensed, and the upper cover plate 2 is placed. Then put the assembled stack into an oven and cure it at 80°C for 1 hour.

[0045] By soldering, the lead ends 122 of the metal sheets 12 of the 1st, 3rd, 5th, 7th ... pieces are connected in series using a first circuit, and the lead ends 122 of the metal sheets 12 of the 2nd, 4th, 6th, 8th ... pieces are connected in series using a second circuit. The welding temperature is 285°C, and then the outside of the piezoelectric ceramic stack after the lead ends 122 are welded is coated with a three-proof paint and cured at 80°C for 12 hours.

[0046] At this point, the bonding preparation of the high driving voltage type piezoelectric ceramic stack is completed. The outer diameter of the piezoelectric ceramic stack is about 10 mm, the height is about 8 mm, the resonant frequency is 100 KHz, the capacitance is 20 nanofarads, and the displacement is about 5.5 um when driven by 1000 V voltage.

[0047] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A piezoelectric ceramic stack, characterized in that: The invention comprises an electrode assembly, wherein the electrode assembly comprises a plurality of electrode components (1) stacked in sequence along a first direction, wherein the electrode component (1) comprises a piezoelectric ceramic sheet (11) and a metal sheet (12), wherein the metal sheet (12) is provided with a through hole (121), and wherein the through hole (121) is filled with glue (13); after adjacent electrode components (1) are stacked, two sides of the metal sheet (12) are respectively attached to the side walls of the piezoelectric ceramic sheet (11) of the adjacent electrode components (1), and the piezoelectric ceramic sheets (11) of the adjacent electrode components (1) are bonded by the glue (13).

2. The piezoelectric ceramic stack according to claim 1, characterized in that: The metal sheet (12) is arranged at the center of the piezoelectric ceramic sheet (11), and the diameter of the metal sheet (12) is smaller than the diameter of the piezoelectric ceramic sheet (11).

3. The piezoelectric ceramic stack according to claim 1, characterized in that: Electrode layers (111) are provided on both sides of the piezoelectric ceramic sheet (11) along the first direction; the electrode layer (111) is attached to the metal sheet (12); and the diameter of the metal sheet (12) is greater than the diameter of the electrode layer (111).

4. The piezoelectric ceramic stack according to claim 1, characterized in that: The metal sheet (12) is provided with a lead-out end (122), the lead-out end (122) of the 2Nth metal sheet (12) along the first direction is connected to a first circuit, and the lead-out end (122) of the 2N-1th metal sheet (12) along the first direction is connected to a second circuit, and N is a positive integer.

5. The piezoelectric ceramic stack according to claim 4, characterized in that: The projections of the center lines of the lead-out ends (122) of the adjacent metal sheets (12) along the first direction are arranged at an angle.

6. The piezoelectric ceramic stack according to claim 1, characterized in that: The piezoelectric ceramic stack further comprises an upper cover plate (2) and a lower cover plate (3), wherein the upper cover plate (2) and the lower cover plate (3) are connected to two ends of the electrode assembly along the first direction.

7. The piezoelectric ceramic stack according to claim 6, characterized in that: The upper cover plate (2) is attached to the metal sheet (12) of the electrode component (1) close to one end of the upper cover plate (2), and the upper cover plate (2) is bonded to the glue (13); and / or The lower cover plate (3) is attached to the metal sheet (12) of the electrode component (1) close to one end of the lower cover plate (3), and the lower cover plate (3) is bonded to the glue (13).

8. The piezoelectric ceramic stack according to claim 6, characterized in that: The upper cover plate (2) and the lower cover plate (3) are made of ceramic.

9. The piezoelectric ceramic stack according to claim 1, characterized in that: The outer wall of the piezoelectric ceramic stack is coated with a protective paint.

10. The piezoelectric ceramic stack according to claim 1, characterized in that: There are a plurality of through holes (121), and the plurality of through holes (121) are evenly arranged on the metal sheet (12).

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