Piezoelectric ceramic actuator and preparation method thereof

Abstract

The invention provides a piezoelectric ceramic actuator and a preparation method thereof. The piezoelectric ceramic actuator comprises a stack body, the stack body comprises a plurality of stack assemblies stacked in the vertical direction, each stack assembly comprises a fissure layer, a plurality of ceramic dielectric layers and a plurality of inner electrode metal layers, and the fissure layer comprises two fissure areas arranged along the two opposite sides of the stack body; the outer electrode piece comprises outer electrode metal layers arranged on the surfaces of the two opposite sides of the stack body and pre-tightening metal layers arranged on the outer surfaces of the outer electrode metal layers and used for applying pre-tightening force to the stack body, and at least one of the outer electrode metal layers and the pre-tightening metal layers extends to the crack area of each stack assembly; and an anchoring part is formed in the crack area, and is fixedly connected with the ceramic dielectric layers on the upper and lower adjacent sides of the anchoring part. According to the technical scheme, the problem that in the prior art, a piezoelectric ceramic actuator is prone to cracking failure due to inertial stress is solved.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric ceramic actuator technology, and more specifically, to a piezoelectric ceramic actuator and its preparation method. Background Technology

[0002] In related technologies, there is a type of piezoelectric actuator, especially large-size stacked structures used in high-dynamic scenarios. During long-term high-frequency service, the piezoelectric actuator is prone to severe tensile stress concentration due to mass inertia, which causes microcracks to form and propagate, leading to cracking and disintegration failure. Summary of the Invention

[0003] The main objective of this invention is to provide a piezoelectric ceramic actuator and its preparation method, so as to solve the problem that piezoelectric ceramic actuators are prone to cracking and failure due to inertial stress in the prior art.

[0004] To achieve the above objectives, the present invention provides a piezoelectric ceramic actuator, comprising: a stacked body including a plurality of stacked assemblies stacked along the vertical direction, each stacked assembly including a slit layer, a plurality of ceramic dielectric layers and a plurality of inner electrode metal layers, the slit layer being bonded between two adjacent ceramic dielectric layers and only in contact with the ceramic dielectric layers, the remaining ceramic dielectric layers and the plurality of inner electrode metal layers being alternately stacked in pairs, the slit layer including two slit regions arranged along opposite sides of the stacked body; and an outer electrode component including an outer electrode metal layer disposed on opposite side surfaces of the stacked body and a pre-tightening metal layer disposed on the outer surface of the outer electrode metal layer for applying a pre-tightening force to the stacked body, at least one of the outer electrode metal layer and the pre-tightening metal layer extending to the slit region of each stacked assembly and forming an anchoring portion in the slit region, the anchoring portion being fixedly connected to the ceramic dielectric layers on both sides thereon to provide a pre-tightening force to the stacked body.

[0005] Furthermore, the thickness of the fracture layer is 0.1 mm to 0.3 mm.

[0006] Furthermore, the width of the fractured region is 30 μm to 70 μm.

[0007] Furthermore, both the outer electrode metal layer and the pre-tightening metal layer extend into the crack region of each stacked assembly to jointly form an anchoring portion in the crack region.

[0008] Furthermore, the thickness of the pre-tightening metal layer is 0.3mm-0.5mm; and / or, the thickness of the external electrode metal layer is 0.05mm-0.1mm.

[0009] Furthermore, the ceramic dielectric layer has mutually perpendicular length and width directions, and two adjacent inner electrode metal layers among the multiple inner electrode metal layers are staggered in the length direction and electrically connected to the outer electrode metal layers on both sides respectively.

[0010] According to another aspect of the present invention, a method for preparing a piezoelectric ceramic actuator is provided. This method is used to prepare the aforementioned piezoelectric ceramic actuator and includes the following steps: S1, obtaining a plurality of ceramic films; S2, obtaining a fissure slurry prepared from an organic pore-forming agent; S3, coating the surface of the ceramic films with an inner electrode metal slurry to form an inner electrode pattern, and then coating the upper surface of the ceramic films with the inner electrode pattern with another ceramic film; S4, repeating step S3 until multiple alternating layers of inner electrode patterns and ceramic films are formed; S5, coating the outer periphery of the surface of the uppermost ceramic film from step S4 with a fissure slurry. S6. Apply a slurry to form a crack pattern; S7. Cover the surface of the ceramic film with the crack pattern with another ceramic film; S8. Continue to repeat step S3 to form multiple alternating layers of inner electrode patterns and ceramic films on the surface of the ceramic film above the crack pattern, thus forming a block; S9. Cut the block to obtain multiple single blanks, and stack the multiple single blanks in the vertical direction to form a stacked blank; S0. Heat treat the stacked blanks to obtain a stacked body, and weld the stacked body to the outer electrode and the pre-tightening metal in sequence to obtain a piezoelectric ceramic actuator containing multiple ceramic dielectric layers, multiple inner electrode metal layers, anchoring parts, outer electrode metal layers and pre-tightening metal layers.

[0011] Furthermore, in step S5, the fissure slurry is made from an organic pore-forming agent.

[0012] Furthermore, the organic pore-forming agent is a starch slurry.

[0013] Furthermore, in step S5, the orthographic projection of the crack pattern on the ceramic diaphragm is a ring, and the ring-shaped crack pattern extends along the circumferential edge of the ceramic diaphragm.

[0014] The piezoelectric ceramic actuator using the technical solution of the present invention, on the one hand, includes a stacked body comprising multiple stacked components, each stacked component having a crack layer, and an anchoring part formed in the crack region by extending the outer electrode metal layer and the pre-tightening metal layer, so that the anchoring part provides a stable pre-tightening force to the stacked component. In this way, the anchoring part can tightly engage with the ceramic dielectric layers on its upper and lower adjacent sides like a "mechanical claw", avoiding the problem of severe tensile stress generated by the piezoelectric ceramic actuator due to inertia during high-frequency driving, which would cause brittle cracking or interlayer disintegration along the interface of the inner electrode metal layer or in the weak area of ​​the structure, thereby significantly improving the structural strength of the piezoelectric ceramic actuator;

[0015] On the other hand, by setting a pre-tightening metal layer to apply pre-tightening force to the stack body, after the stack body completes the room temperature air polarization treatment, its overall dimensions will slightly elongate due to piezoelectric properties. The pre-tightening metal layer will then generate reverse stress, forming a spontaneous flexible pre-tightening effect on the stack body. This pre-tightening force can effectively counteract the inertial tensile force generated by the carbon rod and copper block during high-frequency operation of the piezoelectric ceramic actuator, fundamentally preventing the piezoelectric ceramic actuator from cracking along the inner electrode metal layer or crack edges. This can improve the fatigue resistance of the piezoelectric ceramic actuator and extend the service life of large-size piezoelectric ceramic actuators. Therefore, the piezoelectric ceramic actuator of this application can not only improve the displacement and driving speed, but also solve the problem of cracking and disintegration failure of the motor due to the increased mass inertia and severe tensile stress during high-frequency operation.

[0016] On the other hand, the fabrication method of piezoelectric ceramic actuators also has the advantages of the piezoelectric ceramic actuators mentioned above. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 This diagram illustrates the structure in step S3 of preparing the piezoelectric ceramic actuator of the present invention, in which an internal electrode pattern is formed by printing an internal electrode metal paste on the surface of a ceramic diaphragm.

[0019] Figure 2 This diagram illustrates the structure in step S5 of preparing the piezoelectric ceramic actuator of the present invention, in which the surface of the uppermost ceramic diaphragm is printed with a crack paste to form a crack pattern.

[0020] Figure 3 It shows Figure 1 A schematic diagram of a structure in which an internal electrode pattern is formed by printing internal electrode metal paste on the surface of a ceramic diaphragm from another angle.

[0021] Figure 4 It shows Figure 2 A schematic diagram of the structure from another angle, showing the formation of a crack pattern by printing crack paste on the surface of the uppermost ceramic film;

[0022] Figure 5 A schematic diagram of the structure of the bar block formed in step S7 of preparing the piezoelectric ceramic actuator of the present invention is shown;

[0023] Figure 6 It shows that Figure 5 The diagram shows a stacked blank structure formed by stacking multiple single blanks obtained after cutting the block.

[0024] Figure 7 It shows Figure 6 After the stacked green body is debonded and sintered, the crack slurry is heated and volatilized to form crack regions, thus obtaining a schematic diagram of the stacked body structure.

[0025] Figure 8 It shows Figure 7 A schematic diagram of a structure in which the opposite sides of the stacked body are covered with an outer electrode metal layer, and the outer electrode metal layer extends and fills the crack region.

[0026] Figure 9 It shows in Figure 8 A schematic diagram of a structure in which pre-tightening metal is welded to the outer surface of the external electrode metal layer, and the pre-tightening metal melts and fills the crack area to form a pre-tightening metal layer.

[0027] Figure 10 A schematic diagram of an embodiment of the piezoelectric ceramic actuator of the present invention is shown.

[0028] The above figures include the following reference numerals:

[0029] 1000. Piezoelectric ceramic actuator;

[0030] 100, Bark;

[0031] 200. Stacked unfinished blanks;

[0032] 300. Stacking body;

[0033] 400. External electrode components;

[0034] 10. Single-piece green body; 11. Crack pattern; 12. Internal electrode pattern; 13. Ceramic diaphragm;

[0035] 10' Stacked components;

[0036] 11', Fractured layer; 111, Fractured region;

[0037] 12', Inner electrode metal layer;

[0038] 13', Ceramic dielectric layer;

[0039] 21. External electrode metal layer; 22. Anchoring part; 31. Pre-tightening metal layer. Detailed Implementation

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] This invention provides a method for fabricating a piezoelectric ceramic actuator. The method comprises: S1, obtaining a plurality of ceramic films 13; S2, obtaining a fissure slurry prepared from an organic pore-forming agent; S3, coating the surface of the ceramic films 13 with an inner electrode metal slurry to form an inner electrode pattern 12, and then coating the upper surface of the ceramic films 13 with the inner electrode pattern 12 with another ceramic film 13; S4, repeating step S3 until multiple alternating layers of inner electrode patterns 12 and ceramic films 13 are formed; S5, coating the outer periphery of the surface of the uppermost ceramic film 13 in step S4 with a fissure slurry to form a fissure pattern 11; S6, coating the surface of the ceramic film 13 with the fissure pattern 11 with another ceramic film 13. S7. Continue repeating step S3 to form multiple alternating layers of inner electrode patterns 12 and ceramic films 13 on the surface of the ceramic film 13 on the upper side of the crack pattern 11, thus forming a block; S8. Cut the block to obtain multiple single blanks 10, and stack the multiple single blanks 10 in the vertical direction to form a stacked blank; S9. Heat treat the stacked blanks to obtain a stacked body 300, and weld the stacked body 300 with the outer electrode and the pre-tightening metal in sequence to obtain a piezoelectric ceramic actuator containing multiple ceramic dielectric layers 13', multiple inner electrode metal layers 12', anchoring part 22, outer electrode metal layer 21 and pre-tightening metal layer 31.

[0042] In the above technical solution, a crack pattern 11 is formed by printing crack slurry on a layer of ceramic diaphragm 13 in a multi-layer stacked structure. After debinding and sintering, a through crack region 111 is formed. At least one of the external electrode metal layer 21 and the pre-tightening metal layer 31 extends to the crack region 111 and forms an anchoring part 22, which mechanically engages with the two adjacent ceramic dielectric layers. Thus, when the piezoelectric ceramic actuator is polarized and elongated, the elastic response of the pre-tightening metal layer 31 generates a continuous spontaneous pre-tightening force, which effectively solves the problem of cracking and damage caused by tensile stress due to inertia in piezoelectric ceramic actuators under high-frequency drive. This significantly improves the service reliability and production consistency of piezoelectric ceramic actuators in sizes of 3.0mm×3.0mm×10mm and above.

[0043] In step S9, the heat treatment of the stacked green blanks is carried out by debinding and sintering. The specific sintering and debinding is a conventional technique and will not be described in detail here.

[0044] In some embodiments, in step S5, the crack pattern 11 is made of an organic pore-forming agent, which can form a crack region 111 after sintering. Thus, during the sintering of the stacked green blanks, the organic pore-forming agent volatilizes at high temperature, thereby forming a crack region 111 between the two ceramic dielectric layers 13' of the single green blank 10. The two crack regions 111 form a crack layer 11'. This crack layer 11' does not require subsequent machining or random forming, allowing the outer electrode metal layer 21 and / or the pre-tightening metal layer 31 to extend into the crack region 111 to form the anchoring portion 22. After sintering, the anchoring portion 22 is firmly bonded to the two adjacent ceramic dielectric layers 13' above and below the crack region 111, forming an integrated structure. This effectively buffers the stress concentration caused by inertial tension under high-frequency drive, avoiding the problem of cracking and disintegration of the inner electrode metal layer 12' or ceramic dielectric layer 13' due to uncontrollable crack positions in traditional structures. This significantly improves the overall structural integrity and long-term operational reliability of the piezoelectric ceramic actuator.

[0045] In some embodiments, the organic pore-forming agent is starch slurry, which forms a crack region 111 after sintering and volatilization. In this way, the core area of ​​the starch slurry forms internal stress-relieving cracks after volatilization and decomposition, and the outer extension area forms surface and near-surface pores after decomposition, thus forming the crack region 111. This provides a dedicated anchoring space for the outer electrode metal layer 21 and the pre-tightened metal layer 31. Compared with existing mechanical or inorganic pore-forming technologies, this solution can achieve the pore-forming function using only starch slurry, and the types of raw materials are greatly reduced, which can effectively reduce raw material procurement costs and storage costs.

[0046] Specifically, the starch slurry can be made from organic starches such as potato starch, sweet potato starch, or corn starch, or a combination of the above-mentioned starches can be used.

[0047] like Figure 2 As shown, in some embodiments, in step S5, the orthographic projection of the crack pattern 11 onto the ceramic diaphragm 13 is annular, and the annular crack pattern 11 extends along the circumferential edge of the ceramic diaphragm 13.

[0048] In the above technical solution, the formed crack layer 11' forms a uniform stress relief structure in the stacked assembly 10'. This structure is precisely matched with the geometric boundary of the ceramic dielectric layer 13', ensuring that the stress generated by the inertial tension of the piezoelectric ceramic actuator under high-frequency drive is uniformly distributed along the circumference. At the same time, the crack layer 11' only contacts the ceramic dielectric layer 13' and not the inner electrode metal layer 12', maintaining the integrity of the electrode path.

[0049] It should be noted that in steps S1 to S7, the ceramic diaphragm 13 is made of a suitable PZT (lead zirconate titanate) piezoelectric ceramic green sheet. The internal electrode metal paste is printed onto the ceramic diaphragm 13 through overprinting. Multiple ceramic diaphragms 13 with printed internal electrode metal paste are stacked together to form a structure where the ceramic diaphragm 13 and the internal electrode metal paste are alternately arranged. Crack paste is printed in the stress relief area on the uppermost ceramic diaphragm 13. Then, another ceramic diaphragm 13 is stacked on top of the crack paste. This process of alternately overprinting multiple layers of internal electrode metal paste and ceramic diaphragms 13 continues, forming a block. The block is then cut to obtain multiple single-piece blanks 10. These single-piece blanks 10 are stacked to obtain a stacked blank. The specific structure of the stacked blank is shown in Table 1.

[0050] Table 1

[0051]

[0052] Specifically, a single electrode block comprises 29 layers of internal electrode patterns, 31 layers of ceramic films, and 1 layer of crack patterns. The block is dried in a constant-temperature oven to allow both the internal electrode metal paste and the crack paste to initially solidify, ensuring a strong bond with the ceramic films and preventing structural detachment during subsequent cutting and lamination processes. The core of this step lies in precisely controlling the position and morphology of the crack paste, laying the structural foundation for the formation of the cracked region and the pre-tightening metal anchoring after sintering.

[0053] It should be noted that in step S8, according to actual production needs, multiple completed blocks are cut into single blanks 10 of 3.0mm × 3.0mm × 10.0mm. Five single blanks 10 are then stacked sequentially according to the principle of electrode polarity alignment. During the stacking process, a visual positioning system ensures precise alignment of each crack area, while uniform pressure is applied to ensure tight bonding between layers, forming a gapless integrated stacked blank. Strict control of the polarity direction and crack alignment accuracy (cracks should face the outer electrode side) during this process avoids affecting the overall drive consistency of the actuator. The stacked blank is then completely covered with a flexible encapsulation material, ensuring the covering is wrinkle-free and undamaged to isolate the pressure medium. The stacked blank is then placed in an isostatic press. Under a preset constant pressure for a certain period, the interfaces of the stacked blank are uniformly stressed and tightly bonded, completely eliminating interlayer voids and microbubble defects, and improving the overall density of the stacked blank. This step requires ensuring uniform pressure transmission to avoid insufficient local pressure leading to poor interlayer bonding.

[0054] It should be noted that in step S9, the isostatically pressed stacked green blank is sent to a debinding sintering furnace and heat-treated according to a preset curve of "low-temperature slow heating - medium-temperature holding decomposition - high-temperature complete volatilization". The entire process is carried out in an air atmosphere. By precisely controlling the heating rate and holding time, the organic binder, volatile components of the internal electrode slurry, and crack slurry in the stacked green blank are completely removed, avoiding porosity or cracking due to organic residue in subsequent sintering processes. After debinding, it is necessary to ensure that the stacked green blank has an intact appearance, without deformation or delamination. Then, the debinded stacked green blank is transferred to a high-temperature sintering furnace, and the heating rate is controlled in stages. It is held at different temperature ranges to achieve full material reaction and grain growth. Finally, it is heated to the target sintering temperature and held to complete densification. After sintering, the material is cooled to room temperature at a slow rate to prevent cracking or deformation of the stacked blank due to thermal stress. This ensures that the cracked areas of the starch slurry are integrally sintered with the stacked blank, resulting in a dense and intact stacked body 300. The sintered stacked body 300 is then precision ground using fine-grained abrasive media to refine its length, width, and height until it meets the required dimensions of 3.0mm × 3.0mm × 10.0mm. During grinding, the grinding pressure and feed rate must be controlled to ensure dimensional accuracy and surface finish. After grinding, the surface of the stacked body 300 is cleaned to remove grinding dust and residual impurities, preventing any impact on the subsequent external electrode printing quality.

[0055] Specifically, after the integrated sintering and grinding of the stacked body, silver electrode paste is uniformly coated onto the outer electrode area of ​​the stacked body using a screen printing process, ensuring that the silver electrode paste completely covers the outer electrode area without any omissions. After printing, the stacked body is sent to a high-temperature oven for high-temperature sintering. Sintering allows the silver electrode paste to form a strong metallurgical bond with the stacked body, improving the conductivity and adhesion strength of the outer electrode. This step requires attention to ensure the uniformity of the silver electrode paste thickness, avoiding localized areas that are too thick or too thin, which could lead to uneven conductivity. A low-viscosity silver paste should be selected to ensure good fluidity, allowing it to naturally penetrate into the micron-sized pores and fissures left after the decomposition of the fissure paste. If the silver paste viscosity is too high, it will not be able to fully fill the fissure areas, only adhering to the surface of the stacked body, making it difficult for subsequent pre-tightening metal to form effective anchorage; if the viscosity is too low, paste dripping and blurred edges may occur, affecting the dimensional accuracy of the electrodes. During printing, control the squeegee pressure and printing speed to ensure that the silver paste completely covers the outer electrode area without any omissions.

[0056] Furthermore, in step S9, after the silver electrode paste has cured, the surface of the stacked outer electrode is ultrasonically cleaned with anhydrous ethanol to thoroughly remove surface oil, grinding residue, and other impurities. After natural drying, flux is evenly applied to enhance wettability during subsequent soldering. Low-melting-point solder wire is used for the pre-tightening metal. The solder is evenly melted onto the entire surface of the outer electrode using a soldering gun. The solder simultaneously wets the remaining gaps in the adhesive removal area, forming a continuous and complete solder layer. The solder layer thickness is 0.5 mm, and it must meet the quality requirements of no missed coating, no bubbles, and no pinholes. The interlocking structure of "solder-gaps" significantly improves the structural strength of the outer electrode, solving the problem of insufficient copper foil welding strength in existing technologies.

[0057] Unlike the silicone oil polarization method in related technologies, this embodiment employs a room-temperature air polarization process after the pre-tightening metal is coated. The fabricated piezoelectric ceramic actuator is fixed in a polarization fixture with good conductivity, ensuring close contact between the fixture and the outer electrode layer to guarantee a uniform electric field. A preset polarization voltage is applied and maintained for a certain period after connecting the polarization power supply. The electrical performance of the piezoelectric ceramic actuator before and after polarization is tested to ensure the polarization effect meets standards. This process eliminates the need for silicone oil, simplifying operation and avoiding the impact of silicone oil residue on subsequent assembly. Finally, a laser interferometer is used to detect the displacement of the piezoelectric ceramic actuator under standard operating voltage to ensure it meets design specifications. A high-frequency fatigue testing machine is used to perform over 10,000 cycles of tensile fatigue testing at a frequency commonly used for camera focusing. After testing, the piezoelectric ceramic actuator must show no breakage, deformation, or significant attenuation of displacement performance. Long-term stability testing is conducted under wide temperature and high humidity conditions to ensure the displacement attenuation rate is controlled within allowable limits.

[0058] To address the issue that fissure preparation and electrode printing are often independent processes in related technologies, requiring repeated positioning and calibration, and resulting in cumbersome operations, some embodiments include, before step S1, setting up separate internal electrode printing screens and fissure paste printing screens. By using these separate screens to overlay the internal electrode paste and fissure paste onto the ceramic diaphragm, and utilizing the collaborative operation of the two independent screens, the simultaneous preparation of the internal electrode paste and fissure paste can be completed in a single overlay process. This eliminates the need for additional steps such as zirconia paste preparation and dedicated screen calibration, resulting in higher overall process integration and shorter production time for a single piezoelectric ceramic actuator.

[0059] It should be noted that this embodiment employs a high-precision screen printing process. Two independently designed screens—an inner electrode printing screen and a crack paste printing screen—are used to print the inner electrode metal paste and crack paste, respectively, to quickly perform alternating overprinting of the ceramic film. Specifically, the inner electrode printing and crack pre-setting are as follows: A suitable PZT piezoelectric ceramic green sheet (i.e., a ceramic film) is selected. A high-precision screen printing process is used, employing two independently designed screens (one matching the inner electrode and the crack position) to perform overprinting (two printing screens, one for printing the inner electrode metal paste and the other for printing the starch paste). After alternating overprinting of multiple layers of ceramic film, inner electrode metal paste, and more ceramic film, starch paste is printed in the stress-relief area on the surface of the top ceramic film. Then, multiple layers of ceramic film and inner electrode metal paste are continued to be alternately overprinted until a block is formed. This paste has a pore-forming function—each crack is formed by starch paste, with the outer starch paste corresponding one-to-one with the crack position. After printing, the electrode block is placed in a constant temperature oven to dry, allowing both the inner electrode paste and starch paste layers to initially solidify. This ensures a strong bond between the electrode and the piezoelectric ceramic green sheet (i.e., ceramic film), preventing structural detachment during subsequent cutting and lamination processes. The core of this step lies in precisely controlling the position and morphology of the cracks and starch paste, laying the structural foundation for the formation of pores and solder anchoring after sintering. In this application, the inner electrode and starch paste are laminated in one step using two independent stencils, eliminating the need for secondary crack processing in traditional processes. Subsequent external electrode soldering reinforcement eliminates the need for copper foil cutting and positioning spot welding, reducing welding time by more than 60% compared to copper foil welding. Furthermore, it eliminates the need for customized solder materials, resulting in higher overall process integration and significantly reducing production time and costs. The production time for a single actuator is reduced by more than 30%.

[0060] In one embodiment, the outer electrode metal layer 21 is made of silver paste.

[0061] It should be noted that, addressing the issue of large-size stacked motors being prone to cracking and disintegration under high-frequency drive in applications without preload, this application provides a method for fabricating a piezoelectric ceramic actuator. While ensuring the large-size piezoelectric ceramic actuator can output significant displacement, it significantly improves its structural strength and crack resistance, effectively guaranteeing the motor's durability and reliability, and meeting the practical application requirements of camera lens focusing. The specific implementation process is as follows: First, the inner electrode and starch slurry are simultaneously printed. Two independent screens are designed: one for printing the inner electrode and the other for printing the crack slurry. Overlay printing is performed on the surface of the PZT piezoelectric ceramic green sheet (i.e., ceramic film)—the starch slurry is precisely printed in a preset stress-relief area. This slurry has a pore-forming function, and the starch area used to form the core crack must ensure no overlap with the inner electrode pattern. After the overprinting is completed, the block is cut, stacked and isostatically pressed according to conventional processes to form a densely stacked blank. Then the stacked blank is sent into the debinding and sintering furnace to complete the debinding and sintering process according to the preset curve. During this process, the starch, as an organic medium, will be completely decomposed and volatilized, and finally leave a pore structure on the actuator surface that matches the size of the starch area. After the actuator is ground and refined to the target size of 3.0mm×3.0mm×10mm, the silver paste will naturally penetrate into the pores left after the starch evaporates during the printing process, forming an anchoring base for the "electrode-pore". After the silver paste is sintered and solidified at high temperature, the external electrode is strengthened by soldering. Conventional low-melting-point solder wire is selected, and the solder is evenly melted onto the entire surface of the external electrode through a soldering gun. At this time, the solder will simultaneously wet the pores filled with silver paste, and finally form a continuous and complete solder layer with a thickness of about 0.5mm. This solder layer is not simply attached to the surface of the actuator. The solder structure recessed in the pores is like a "mechanical claw" that tightly bites into the stacked body, which significantly improves the bonding strength between the solder layer and the ceramic diaphragm.

[0062] In one embodiment, using the above-described method for fabricating piezoelectric ceramic actuators, the stack body size is controlled to be 3.0mm × 3.0mm × 10.0mm, the number of stack components 10' is 5, the crack regions of a single stack component 10' are two oppositely arranged, the thickness of the pre-tightening metal layer 31 is 0.3mm, and the piezoelectric ceramic actuators with crack region widths of 0.1mm, 0.2mm and 0.3mm respectively are subjected to different driving frequency operation life tests using a working voltage of 0V-15V (sine wave). The data are shown in Table 2.

[0063] It should be noted that the width of the fracture region 111 refers to... Figure 7 As shown, the crack region 111 extends from the outer surface of the stacked body to the interior of the stacked body.

[0064] Table 2

[0065]

[0066] In one embodiment, using the above-described method for fabricating piezoelectric ceramic actuators, the stack body size is controlled to be 3.0mm × 3.0mm × 10.0mm, the number of stack components 10' is 5, the crack regions of a single stack component 10' are two oppositely arranged, the thickness of the pre-tightening metal layer 31 is 0.4mm, and the operating voltage of 0V-15V (sine wave) is used to conduct operating life tests at different driving frequencies on three piezoelectric ceramic actuators with crack region widths of 0.1mm, 0.2mm and 0.3mm respectively. The data are shown in Table 3.

[0067] Table 3

[0068]

[0069] In one embodiment, using the above-described method for fabricating piezoelectric ceramic actuators, the stack body size is controlled to be 3.0mm × 3.0mm × 10.0mm, the number of stack components 10' is 5, the crack regions of a single stack component 10' are two oppositely arranged, the thickness of the pre-tightening metal layer 31 is 0.5mm, and the operating life test of three piezoelectric ceramic actuators with crack region widths of 0.1mm, 0.2mm and 0.3mm respectively is conducted at different driving frequencies using a working voltage of 0V-15V (sine wave). The data are shown in Table 4.

[0070] Table 4

[0071]

[0072] Based on the combined experimental data from the three sets, the actuator's continuous operating time is optimal when the solder layer thickness is 0.4mm~0.5mm and the starch width is 0.2mm~0.3mm. The core advantage of this parameter range lies in the precise structural match between the solder layer thickness and the crack width—a 0.3mm~0.5mm solder layer provides sufficient structural reinforcement without limiting high-frequency deformation due to excessive rigidity; the 0.3mm~0.5mm crack width creates a pore that firmly anchors the solder layer while preventing a porous substrate, ensuring uniform stress release during high-frequency operation from 10K to 40KHz, thus maximizing lifespan.

[0073] It should be noted that the specification parameter range is (3-5) mm × (3-5) mm × (10-15) mm; the number of crack layers in a single stacked component is an even number of layers, and it is ≥2 layers; the number of crack layers in the actuator = the number of crack layers in a single stacked component × the number of single pieces.

[0074] In summary, the advantages of this application are mainly reflected in the following four aspects:

[0075] First, the material system is simplified, completely eliminating the use of zirconium oxide slurry and achieving the pore-forming function only through conventional starch slurry. The types of raw materials are reduced by 40%, significantly reducing procurement and storage costs.

[0076] Secondly, the process efficiency is significantly improved. The inner electrode and functional starch can be overprinted in one step using two independent stencils, eliminating cumbersome processes such as zirconium oxide slurry preparation and stencil calibration. The printing time of a single actuator is reduced by more than 30%, and the subsequent external electrode soldering reinforcement still maintains the high efficiency of copper foil-free soldering, resulting in an overall production efficiency increase of 50%.

[0077] Third, the structure has better synergy. The composite structure of "starch-derived cracks + hole-anchored solder layer" not only accurately releases the internal stress during high-frequency operation through the micron-level cracks formed by starch decomposition, but also improves the structural reinforcement effect by more than 3 times through the interlocking effect of the hole and solder. Combined with the pre-tightening mechanism of the pre-tightened metal layer, the fatigue life of the piezoelectric ceramic actuator is increased by 1.5 times compared with the traditional solution.

[0078] Fourth, the production line is more adaptable. The core process does not require the addition of new zirconia-related printing and sintering control modules. It is fully compatible with existing piezoelectric ceramic actuator production lines, with zero investment in equipment modification. Enterprises can quickly achieve technology transformation and mass production.

[0079] like Figures 1 to 10 As shown, an embodiment of the present invention provides a piezoelectric ceramic actuator 1000, comprising:

[0080] The stacked body 300 includes multiple stacked components 10' stacked along the vertical direction. Each stacked component 10' includes a fracture layer 11', multiple ceramic dielectric layers 13', and multiple inner electrode metal layers 12'. The fracture layer 11' is bonded between two adjacent ceramic dielectric layers 13' and only contacts the ceramic dielectric layers 13'. The remaining ceramic dielectric layers 13' and the multiple inner electrode metal layers 12' are stacked alternately in pairs. The fracture layer 11' includes two fracture regions 111 arranged along opposite sides of the stacked body 300.

[0081] The external electrode 400 includes an external electrode metal layer 21 disposed on opposite side surfaces of the stack body 300 and a pre-tightening metal layer 31 disposed on the outer surface of the external electrode metal layer 21 for applying pre-tightening force to the stack body 300. At least one of the external electrode metal layer 21 and the pre-tightening metal layer 31 extends to a crack region 111 of each stack assembly 10' and forms an anchoring portion 22 in the crack region 111. The anchoring portion 22 is fixedly connected to the ceramic dielectric layers 13' on both sides to provide pre-tightening force to the stack body 300.

[0082] In the above technical solution, on the one hand, by setting a crack layer 11' in the stacked assembly 10' and stacking multiple stacked assemblies 10' to form a stacked body 300, the outer electrode metal layer 21 and the pre-tightening metal layer 31 extend into the crack region 111 and form an anchoring part 22 in the crack region 111, so that the anchoring part 22 provides a stable pre-tightening force for the stacked assembly 10'. In this way, the anchoring part 22 can tightly engage with the ceramic dielectric layers 13' on its upper and lower adjacent sides like a "mechanical claw", avoiding the piezoelectric ceramic actuator 1000 from generating severe tensile stress due to inertia during high-frequency driving, which would cause brittle cracking or interlayer disintegration along the interface of the inner electrode metal layer 12' or the weak area of ​​the structure, thereby significantly improving the structural strength of the piezoelectric ceramic actuator.

[0083] On the other hand, by providing a pre-tightening metal layer 31 to apply pre-tightening force to the stack body 300, after the stack body 300 completes the room temperature air polarization treatment, its overall dimensions will slightly elongate due to piezoelectric characteristics. The pre-tightening metal layer 31 will then generate reverse stress, forming a spontaneous flexible pre-tightening effect on the stack body 300. This pre-tightening force can effectively counteract the inertial tensile force generated by the carbon rod and copper block during high-frequency operation of the piezoelectric ceramic actuator, fundamentally preventing the piezoelectric ceramic actuator from cracking along the inner electrode metal layer 12' or crack edges. This can improve the fatigue resistance of the piezoelectric ceramic actuator and extend the service life of large-size piezoelectric ceramic actuators. Therefore, the piezoelectric ceramic actuator of this application can improve displacement and driving speed while also solving the problem of cracking and disintegration failure of the motor due to the increased mass inertia and severe tensile stress during high-frequency operation.

[0084] In piezoelectric ceramic stack actuators of related technologies, copper foil or copper sheet is used as the external electrode material. These metal electrode materials themselves lack elasticity or pre-tightening function and cannot provide pre-tightening force to the stack body. Therefore, such actuators must rely on external mechanical pre-tightening mechanisms (such as springs, bolts, or clamps) or apply external loads to maintain good contact between the electrode and the ceramic substrate, avoiding poor contact, conductivity failure, or interlayer debonding due to thermal expansion differences or vibration. Therefore, in some embodiments, the pre-tightening metal layer 31 is a solder layer formed on the side of the external electrode metal layer 21 facing away from the stack assembly 10', with a thickness ranging from 0.3 mm to 0.5 mm, preferably 0.5 mm. The solder material itself has a certain degree of elasticity, sufficient to accommodate the slight expansion of the stack body 300 after room temperature air polarization, and to apply reverse stress to the stack body 300, thereby applying an adaptive, non-external flexible pre-tightening force to the stack body 300. This preload is generated spontaneously by the elastic properties of the solder layer, requiring no additional mechanical structure. It effectively counteracts the tensile stress caused by inertia during high-frequency driving, significantly improving the structural integrity and service reliability of the stack. Therefore, this application solves the problem that existing large-size stack products cannot be used in scenarios without preload.

[0085] It should be noted that the crack region 111 does not overlap with the inner electrode metal layer, and the crack region 111 does not interfere with the conductivity of the inner electrode metal layer. The two crack regions 111 are located on opposite sides along the stack body 300.

[0086] Specifically, the dimensions of the stacked body 300 range from (3.0mm-5.0mm) × (3.0mm-5.0mm) × (10mm-15mm). This large-size stacked body 300 design allows for longer displacement output and higher driving speeds compared to smaller-size stacked body 300s. This enables the piezoelectric ceramic actuator to achieve a displacement of up to 1.5μm under standard driving voltage, and the motor driving speed to reach a maximum of 45mm / s, more than twice that of traditional small-size motors. This solves the problem that existing small-size impact-type inertial motors cannot meet the high demands for lens focusing speed in scenarios such as dynamic camera capture and video tracking, effectively improving camera focusing speed and enhancing user experience.

[0087] In some embodiments, the thickness of the crack layer 11' is 0.1mm-0.3mm. By limiting the thickness of the crack layer 11', the internal stress during high-frequency operation can be precisely released through the micron-level cracks in the crack layer 11'. Furthermore, the interlocking action between the anchoring part 22 and the ceramic dielectric layer 13' strengthens the structure of the stacked body 300, ensuring the long-term reliable operation of the piezoelectric ceramic actuator under high-frequency and large-displacement conditions, thereby meeting the balance requirements between stress release and structural rigidity.

[0088] It should be noted that, to ensure the total thickness of the starch paste after printing remains stable at around 200μm-300μm (the thickness of the starch layer before sintering), a 2-3 overprinting process can be used when printing the starch paste. That is, printing 2-3 times forms one starch layer, with the thickness of each print controlled at 70μm-100μm (actual screen thickness). After the first print, the blank with the starch paste should be placed in a constant temperature oven at 60°C-80°C for 15-20 minutes to dry, allowing the paste to initially solidify before subsequent overprinting, in order to avoid interlayer delamination caused by multiple prints. If the single print or the total thickness is insufficient, the cracks formed after starch decomposition during sintering are easily closed due to the shrinkage of the ceramic matrix. If the total thickness is too thick, the crack opening size will be too large after sintering, resulting in a significant decrease in the overall stiffness of the actuator, and fracture defects along the cracks are likely to occur during subsequent dimensional grinding. By combining two to three overprinting processes with segmented drying, the natural opening size of the cracks after sintering can be kept stable at 0.1 mm - 0.3 mm, thus meeting the requirements for stress release and structural rigidity balance of the stacked body 300.

[0089] In some embodiments, the width of the crack region 111 is 30 μm to 70 μm. This width range allows the crack region 111 to form a controlled stress release path on both sides of the stacked assembly 10', and limits the width of the anchoring portion 22 formed by the external electrode metal layer 21 or the preload metal layer 31 in the crack region 111. If the width of the crack region 111 is less than 30 μm, the stress release path is too short and cannot adequately buffer the tensile energy inside the large-size actuator, leading to the problem of microcracks being easily induced at the crack edge or the interface of the adjacent ceramic dielectric layer 13'. If the width exceeds 70 μm, it may cause the crack region 111 to be too wide, weakening the mechanical stiffness of the overall structure and affecting the actuation response accuracy and preload transmission efficiency. A crack region width of 30 μm to 70 μm can significantly improve the crack resistance and long-term reliability of the large-size piezoelectric ceramic actuator under high-frequency operating conditions.

[0090] In related technologies, piezoelectric ceramic actuators are assembled with epoxy resin and do not have a preload adjustment structure. After increasing the size of the stacked body, the strong inertial pulling force generated by the piezoelectric ceramic actuator during high-frequency operation will cause the piezoelectric ceramic actuator to crack and disintegrate along the inner electrode layer or the weak point of the structure, resulting in a very short service life.

[0091] like Figure 9 As shown, in some embodiments, the outer electrode metal layer 21 and the pre-tightening metal layer 31 both extend to the crack region 111 of each stack assembly 10' to jointly form an anchoring portion 22 in the crack region 111.

[0092] In the above technical solution, the anchoring part 22 and the ceramic dielectric layer 13' on both sides of the crack region 111 are directly fixedly connected during the sintering process, so that the outer electrode metal layer 21 and the pre-tightening metal layer 31 form a double-layer cooperative anchoring part 22 in the crack region 111. The outer electrode metal layer 21 will naturally penetrate into the crack region 111 left after the starch slurry evaporates to form an anchoring base. After the high-temperature sintering and curing of the outer electrode metal layer 21 is completed, solder is uniformly melted onto the outer surface of the outer electrode metal layer 21 by a soldering gun. At this time, the solder will simultaneously fill the crack region 111 where the outer electrode metal layer 21 already exists. In this way, the electrode material constituting the outer electrode metal layer 21 and the solder constituting the pre-tightening metal layer 31 together form the anchoring part 22 to improve the structural strength of the piezoelectric ceramic actuator. This allows the alternating stress generated by the inertial tension of the stacked body 300 under high-frequency drive to be effectively suppressed, thereby improving the structural integrity and service life of the piezoelectric ceramic actuator under high-frequency operating conditions. Therefore, this application solves the problems of easy cracking and disintegration and poor durability and service reliability when the size of the stacked body increases.

[0093] In some embodiments, the thickness of the pre-tightening metal layer 31 is 0.3mm-0.5mm. In this way, the pre-tightening metal layer 31 can have both sufficient structural stiffness and elastic deformation capability under high-frequency driving conditions, thereby stably providing pre-tightening force suitable for large-size stacked bodies.

[0094] Specifically, the thickness of the pre-tightening metal layer 31 is preferably 0.5 mm.

[0095] In some embodiments, the thickness of the outer electrode metal layer 21 is set to 0.05mm-0.1mm. This ensures good conductivity and reliable connection with the inner electrode metal layer 12', while also allowing for better coordination with the pre-tightened metal layer 31 to form a stable anchoring portion 22. This improves the bonding strength with the ceramic dielectric layer 13' and enhances the reliability and durability of the piezoelectric ceramic actuator under high-frequency and high-stress conditions.

[0096] In related technologies, piezoelectric ceramic actuators require multi-point welding of copper foil or copper sheets forming the external electrode, which is a complex welding process and time-consuming. Therefore, in some embodiments, the external electrode metal layer 21 is made of silver paste. By applying the silver paste to the periphery of the stacked assembly 10' with the already formed crack layer 11' using a screen printing process, the silver paste naturally penetrates into the cracks in the crack region 111. High-temperature sintering then solidifies the silver paste to form the external electrode metal layer 21, allowing the anchoring portion 22 formed by the silver paste to be naturally and securely connected to the ceramic dielectric layers 13' on both sides, preventing detachment. This avoids the need for multi-point welding of the external electrode, effectively shortening production time and improving production efficiency.

[0097] like Figure 8 As shown, in some embodiments, the ceramic dielectric layer 13' has a length direction and a width direction that are perpendicular to each other, and two adjacent inner electrode metal layers 12' among the plurality of inner electrode metal layers 12' are staggered in the length direction and are electrically connected to the outer electrode metal layers 21 on both sides respectively.

[0098] In the above technical solution, the staggered arrangement of the inner electrode metal layers 12' enables the electric field to form alternating polar regions along the length of the stacked body, effectively dispersing the problem of strong electric field concentration at the electrode edge when arranged in the same direction, which causes local stress concentration in the ceramic dielectric layer 13' around the crack region 111 due to the electric field gradient.

[0099] On the other hand, the technical solution of this embodiment does not require the addition of new zirconia-related printing and sintering control modules, and can be fully compatible with existing piezoelectric ceramic actuator production lines. The equipment modification investment is low, and enterprises can quickly realize technology transformation and mass production.

[0100] It should be noted that the length direction refers to... Figure 8 The left and right directions and the width direction refer to Figure 8 The direction perpendicular to the paper.

[0101] This application has the following advantages:

[0102] 1. This application uses an independently designed internal electrode printing screen and a starch slurry printing screen to simultaneously print starch slurry with pore-forming function during the overprinting stage of raw ceramic sheets. Combined with debinding and sintering, the starch is completely decomposed and volatilized, forming micron-level stress-relieving cracks corresponding to the core area of ​​the starch. The crack width (0.1mm) and distribution can be precisely controlled and there is no interference with the internal electrode area.

[0103] 2. In this application, the starch paste forms internal cracks, and after the glue is removed from its outer extension area, it leaves a hole structure. The silver paste used for the external electrode will naturally penetrate into the hole to form an anchoring base. The subsequent solder layer will also simultaneously wet the hole. Through the three-dimensional interlocking structure of "silver paste-hole-solder", the metal layer of the external electrode is more firmly bonded to the stacked body, and the problem of easy detachment due to simple adhesion is completely solved.

[0104] 3. This application replaces copper foil welding with a full-surface solder coating. The solder layer thickness reaches 0.3mm-0.5mm. At the same time, the starch-derived pores form a "mechanical claw" type interlocking structure, which greatly enhances the reinforcement effect compared with the traditional solution. Furthermore, the elasticity of the solder itself can form a spontaneous flexible pre-tightening force after the actuator is polarized and elongated, further improving the actuator's tensile strength.

[0105] 4. This application achieves an integrated structural design of "cracks and pores" by printing starch paste in one step. After the starch core area decomposes, it forms internal stress-relieving cracks, and after the outer extension area decomposes, it forms surface and near-surface pores, providing a dedicated anchoring space for silver paste penetration and solder wetting.

[0106] 5. This application, through the collaborative design of two independent stencils, can complete the synchronous preparation of the inner electrode and the functional starch paste in just one overprint, eliminating the need for additional processes such as zirconium oxide paste preparation and special stencil calibration. Subsequent external electrode soldering and strengthening does not require copper foil cutting, positioning spot welding and other steps, resulting in higher overall process integration and reducing the production time of a single actuator by more than 30%.

[0107] The advancement of this application compared to the prior art is as follows:

[0108] 1. Significantly improves structural strength and solves cracking problems at the root: The internal stress during high-frequency operation is precisely released through starch-derived micron-level cracks. Combined with the composite structure of "silver paste penetration through the pores + solder wetting and interlocking", the bonding strength between the solder layer and the stacked body is significantly improved compared with existing technologies. The spontaneous pre-tightening force formed by the elasticity of the polarized solder can effectively offset the inertial pulling force between the carbon rod and the copper block, completely solving the industry pain point that large-size actuators are prone to cracking and disintegration along the inner electrode layer or weak points.

[0109] 2. Extend fatigue life to meet the long-term needs of consumer electronics: The triple protection mechanism of "stress release (starch cracks) + structural reinforcement (hole soldering) + self-pre-tightening (solder elasticity)" significantly improves the fatigue life of the 3.0mm×3.0mm×10.0mm actuator, and there is no performance degradation after high-frequency operation, which fully meets the stringent requirements of consumer electronics devices for long-term service characteristics.

[0110] 3. Enhance the stability of external electrode components and avoid failure during service: The anchoring base formed by the silver paste penetration through the pores and the "mechanical claw" interlocking structure of the solder completely solve the problem of easy detachment of existing external electrode components due to simple adhesion; the 0.5mm thick continuous solder layer can effectively protect the metal layer of the external electrode, reduce the impact of environmental factors such as moisture and vibration on conductivity, and improve the working stability of the actuator.

[0111] 4. Adaptable to existing production lines, lowering the threshold for technology implementation: Core processes such as screen printing, integrated co-firing, and room temperature polarization are all compatible with existing piezoelectric ceramic actuator production equipment. Mass production can be achieved without large-scale production line modifications, significantly reducing the company's technology investment and implementation costs, and facilitating rapid commercialization.

[0112] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: By setting a crack layer in the stacked assembly and stacking multiple stacked assemblies to form a stacked body, the outer electrode metal layer and the pre-tightening metal layer extend into the crack region and form an anchoring part in the crack region, so that the anchoring part provides a stable pre-tightening force for the stacked assembly. In this way, the anchoring part can tightly engage with the ceramic dielectric layers on both sides like a "mechanical claw", avoiding the problem that the piezoelectric ceramic actuator will generate severe tensile stress due to inertia during high-frequency driving, which would cause brittle cracking or interlayer disintegration along the interface of the inner electrode metal layer or the weak area of ​​the structure. This significantly improves the structural strength of the piezoelectric ceramic actuator. Furthermore, by incorporating a pre-tightening metal layer to apply pre-tightening force to the stacked body, after the stacked body undergoes room-temperature air polarization treatment, its overall dimensions will slightly elongate due to piezoelectric properties. The pre-tightening metal layer will then generate reverse stress, creating a spontaneous flexible pre-tightening effect on the stacked body. This pre-tightening force effectively counteracts the inertial tensile force generated by the carbon rod and copper block during high-frequency operation of the piezoelectric ceramic actuator, fundamentally preventing cracking along the inner electrode metal layer or crack edges. This improves the fatigue resistance of the piezoelectric ceramic actuator and extends the service life of large-size piezoelectric ceramic actuators. Therefore, the piezoelectric ceramic actuator of this application, while increasing displacement and driving speed, can also solve the problem of cracking and disintegration failure of the motor due to increased mass inertia and severe tensile stress during high-frequency operation.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A piezoelectric ceramic actuator, characterized in that, include: The stacked body (300) includes a plurality of stacked components (10') stacked along the vertical direction. Each stacked component (10') includes a fracture layer (11'), a plurality of ceramic dielectric layers (13') and a plurality of internal electrode metal layers (12'). The fracture layer (11') is bonded between two adjacent ceramic dielectric layers (13') and only contacts the ceramic dielectric layers (13'). The remaining ceramic dielectric layers (13') and the plurality of internal electrode metal layers (12') are stacked alternately in pairs. The fracture layer (11') includes two fracture regions (111) arranged along opposite sides of the stacked body (300). The external electrode component (400) includes an external electrode metal layer (21) disposed on opposite side surfaces of the stack body (300) and a pre-tightening metal layer (31) disposed on the outer surface of the external electrode metal layer (21) and used to apply pre-tightening force to the stack body (300). At least one of the external electrode metal layer (21) and the pre-tightening metal layer (31) extends to the crack region (111) of each stack assembly (10') and forms an anchoring portion (22) in the crack region (111). The anchoring portion (22) is fixedly connected to the ceramic dielectric layers (13') on both sides thereon to provide pre-tightening force to the stack body (300).

2. The piezoelectric ceramic actuator according to claim 1, characterized in that, The thickness of the fracture layer (11') is 0.1mm-0.3mm.

3. The piezoelectric ceramic actuator according to claim 1, characterized in that, The width of the fissure region (111) is 30 μm to 70 μm.

4. The piezoelectric ceramic actuator according to any one of claims 1 to 3, characterized in that, The outer electrode metal layer (21) and the pre-tightening metal layer (31) both extend to the crack region (111) of each of the stacked assemblies (10') to jointly form an anchor (22) in the crack region (111).

5. The piezoelectric ceramic actuator according to any one of claims 1 to 3, characterized in that, The thickness of the pre-tightening metal layer (31) is 0.3mm-0.5mm; and / or the thickness of the outer electrode metal layer (21) is 0.05mm-0.1mm.

6. The piezoelectric ceramic actuator according to any one of claims 1 to 3, characterized in that, The ceramic dielectric layer (13') has a length direction and a width direction that are perpendicular to each other. Two adjacent inner electrode metal layers (12') among the plurality of inner electrode metal layers (12') are staggered in the length direction and are electrically connected to the outer electrode metal layers (21) on both sides respectively.

7. A method for preparing the piezoelectric ceramic actuator according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Obtain multiple ceramic membranes (13). S2. Obtain the fracture slurry prepared from the organic pore-forming agent; S3. A layer of internal electrode metal paste is applied to the surface of the ceramic diaphragm (13) to form an internal electrode pattern (12), and then a ceramic diaphragm (13) is applied to the surface of the ceramic diaphragm (13) with the internal electrode pattern (12). S4. Repeat step S3 until a multilayered alternating internal electrode pattern (12) and a ceramic film (13) are formed. S5. Then, a layer of crack slurry is applied to the outer edge of the surface of the uppermost ceramic film (13) in step S4 to form a crack pattern (11). S6. Then, a ceramic film (13) is applied to the surface of the ceramic film (13) with the crack pattern (11). S7. Continue repeating step S3 to form a multi-layered alternating inner electrode pattern (12) and ceramic film (13) on the surface of the ceramic film (13) above the crack pattern (11), thus forming a bar block; S8. Cut the block to obtain multiple single blanks (10), and stack the multiple single blanks (10) in the vertical direction to form a stacked blank. S9. Heat treatment is performed on the stacked blank to obtain the stacked body (300). The stacked body (300) is then sequentially welded with the outer electrode and the pre-tightening metal to obtain a piezoelectric ceramic actuator containing multiple ceramic dielectric layers (13'), multiple inner electrode metal layers (12'), an anchoring part (22), an outer electrode metal layer (21), and a pre-tightening metal layer (31).

8. The method for preparing the piezoelectric ceramic actuator according to claim 7, characterized in that, In step S5, the fissure slurry is made from an organic pore-forming agent.

9. The method for preparing the piezoelectric ceramic actuator according to claim 8, characterized in that, The organic pore-forming agent is a starch slurry.

10. The method for preparing the piezoelectric ceramic actuator according to claim 7, characterized in that, In step S5, the orthographic projection of the crack pattern (11) on the ceramic diaphragm (13) is an annular shape, and the annular crack pattern (11) extends along the circumferential edge of the ceramic diaphragm (13).

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