Piezoelectric actuator
By adopting a structure in which ceramic insulating layers and electrodes are alternately arranged in the piezoelectric actuator, the problem of unstable insulation layer performance of the center through-hole piezoelectric actuator is solved, higher insulation wear resistance and long-term stability are achieved, and the process flow is simplified.
Patent Information
- Application Number
- CN202422415810.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2025-09-09
- Estimated Expiration
- 2034-09-30
AI Technical Summary
Existing center-through-hole piezoelectric actuators have problems with insulation processing, such as complex processes, easy wear of the coating, and poor long-term stability, which affect their promotion in high-end application fields.
The structure adopts an alternating arrangement of ceramic insulating layers and electrodes. The pole piece of the electrode has a second through hole coaxial with the central through hole to ensure the insulation effect, and the connection of electrodes of the same polarity is achieved through the pin part to avoid short circuit.
The insulation performance and wear resistance of the center through hole are improved, the impact of environmental factors is reduced, the risk of short circuit is avoided, and the process flow is simplified.
Smart Images
Figure CN223322387U_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of piezoelectric actuators, and more specifically, relates to a piezoelectric actuator. Background Art
[0002] Against the backdrop of rapid technological advancements, piezoelectric actuators, as precision components integrating micro-drive and micro-control functions, are becoming increasingly important. They demonstrate broad application potential in cutting-edge fields such as mechanical manufacturing, optical instruments, and communications technology. These fields place extremely high demands on actuator precision, response speed, and environmental adaptability. Piezoelectric actuators with a central through-hole, due to their unique design, are particularly valuable in specific applications such as optical fiber stretching systems and precision mechanical assembly.
[0003] Fiber-optic communication technology is the cornerstone of modern information transmission. Precise control of fiber length is crucial for achieving optical pulse delay and optimizing signal transmission quality. The central through-hole piezoelectric actuator was developed precisely to meet this demand. Its design cleverly incorporates a through-hole structure at the center of the actuator, facilitating the insertion and securing of the optical fiber. The piezoelectric effect also directly applies tensile strain to the fiber, enabling precise adjustment of the fiber's length. This in turn controls the transmission time of the optical pulse and improves the overall performance of the communication system.
[0004] However, in the manufacturing process of center-through-hole piezoelectric actuators, how to effectively achieve insulation treatment of the center through-hole while ensuring the wear resistance and long-term stability of the structure has become a technical problem that needs to be solved urgently. Traditional manufacturing methods mostly use organic coatings on the inner wall of the center through-hole to achieve insulation. Although this method can meet the insulation requirements to a certain extent, it has defects such as complex process, easy wear of the coating, and poor long-term stability. Organic coatings are easily affected by environmental factors such as temperature, humidity changes and mechanical friction during long-term use, resulting in a decrease in insulation performance and may even cause safety hazards such as short circuits, which seriously restricts the promotion and application of center-through-hole piezoelectric actuators in high-end application fields. Utility Model Content
[0005] The purpose of the embodiments of the present application is to provide a piezoelectric driver to solve the technical problem of unstable performance of the insulation layer at the central through hole of the piezoelectric driver existing in the prior art.
[0006] To achieve the above objectives, the technical solution adopted in this application is:
[0007] A piezoelectric actuator is provided, comprising:
[0008] A plurality of sequentially stacked piezoelectric drive stacks, wherein the piezoelectric drive stacks include a plurality of sequentially stacked piezoelectric drive chips, each of which includes a ceramic insulating layer and electrodes, wherein the ceramic insulating layer and the electrodes are alternately arranged in sequence;
[0009] The ceramic insulating layer has a first through hole; the electrode includes a pole piece portion and a pin portion, and the pole piece portion has a second through hole coaxially arranged with the first through hole and having a diameter larger than the first through hole; the projection of the pole piece portion along the thickness direction is within the outer contour projection of the ceramic insulating layer, and the pin portion extends to the outer contour edge of the ceramic insulating layer.
[0010] As a further improvement of the above technical solution:
[0011] Optionally, the electrode includes a positive electrode and a negative electrode, the positive electrode and the negative electrode are arranged alternately in sequence, the ceramic insulating layer is arranged between the positive electrode and the negative electrode, the pin portion of the positive electrode faces one side of the piezoelectric driving chip plane, and the pin portion of the negative electrode faces the other side of the piezoelectric driving chip plane.
[0012] Optionally, the piezoelectric drive stack further includes end surface conductive layers arranged in pairs, and the end surface conductive layers arranged in pairs are respectively arranged on both sides of the piezoelectric drive stack, one of the end surface conductive layers arranged in pairs is electrically connected to the positive electrode; and the other of the end surface conductive layers arranged in pairs is electrically connected to the negative electrode.
[0013] Optionally, the minimum distance from the first through hole to the second through hole is greater than 0.01 mm.
[0014] Optionally, the aperture of the first through hole ranges from 1 mm to 20 mm.
[0015] The present application also provides a method for manufacturing a piezoelectric actuator, comprising the following steps:
[0016] Preparation of green tape: Piezoelectric ceramic powder is slurried and then tape-casted to obtain a green tape of a certain thickness, and holes are punched in the green tape;
[0017] Printed electrodes: Printing electrode patterns on green porcelain tape;
[0018] Preparation of green blocks: After the green porcelain strips are stacked one by one to a certain thickness, they are pressed into green blocks by isostatic pressing;
[0019] Cutting the green block: cutting the green block into individual green blocks;
[0020] Opening a center hole: opening a center hole on each individual green compact;
[0021] Debinding and sintering: Each green body is placed in a debinding furnace for heating to remove the colloid in the green body; then transferred to a sintering furnace to sinter into a piezoelectric driver chip;
[0022] Grinding: Grind the piezoelectric driver chip to the specified shape and size;
[0023] Bonding alignment: bonding the piezoelectric driver chips one by one into a piezoelectric driver stack;
[0024] Plating an end surface conductive layer: Plating an end surface conductive layer on both ends of the piezoelectric drive stack;
[0025] Welding leads: Weld the positive and negative leads on the end surface conductive layer;
[0026] Polarization treatment: The piezoelectric drive stack with welded leads is polarized.
[0027] As a further improvement of the above technical solution:
[0028] Optionally, the step of forming a central hole on each individual green compact may be performed after the step of cutting the green compact, or after the debinding and sintering step, or after the bonding and alignment step.
[0029] Optionally, when printing the electrodes, a printing screen is used to print the electrode pattern, wherein the printing screen has a plurality of electrode patterns arranged in a rectangular array and also has positioning holes and cutting line holes surrounding the outside of the rectangular array.
[0030] Optionally, when preparing the green porcelain tape, the thickness of the green porcelain tape ranges from 20 μm to 80 μm.
[0031] Optionally, when preparing the green block, the number of layers of green porcelain tape is in the range of 40 to 200 layers.
[0032] Compared with the prior art, the piezoelectric actuator provided by this application has the following advantages:
[0033] The piezoelectric driver provided herein comprises multiple stacked piezoelectric driver stacks. The piezoelectric driver's drive expansion and contraction capacity is equal to the sum of the drive expansion and contraction capacity of each piezoelectric driver stack. The piezoelectric driver stack comprises multiple stacked piezoelectric driver chips, which serve as the smallest functional unit of the piezoelectric driver. The sum of the drive expansion and contraction capacity of each piezoelectric driver chip is equal to the drive expansion and contraction capacity of the piezoelectric driver stack. The piezoelectric driver chip specifically comprises a ceramic insulating layer and electrodes. The ceramic insulating layer and the electrodes are arranged alternately to form the piezoelectric driver chip. The ceramic insulating layer has a first through-hole, which is also the center hole of the ceramic insulating layer. The electrode comprises a pole piece and a lead portion. To ensure better insulation at the center hole, the pole piece has a second through-hole coaxially arranged with the first through-hole and having a larger diameter than the first through-hole. Because the diameter of the second through-hole is larger than the diameter of the first through-hole, a ceramic insulating ring is provided between the edge of the electrode and the edge of the center hole, which serves as insulation. Current cannot cross this ceramic insulating ring to conduct to the electrode in the adjacent layer, thus preventing short circuits and other problems. This section of ceramic insulating ring replaces the organic insulating layer at the center hole of the traditional piezoelectric driver. The performance of the ceramic insulating ring is more stable than that of the organic insulating layer, and the impact of environmental factors such as temperature and humidity on the ceramic insulating ring is also smaller. Moreover, the ceramic insulating ring is smoother and more wear-resistant than the organic insulating layer, and no longer requires a complex coating process. In addition, the projection of the pole piece along the thickness direction is within the projection of the outer contour of the ceramic insulating layer. Its purpose is also to ensure absolute insulation from the electrodes in the adjacent layer and prevent the pole piece from touching the outer contour edge of the ceramic insulating layer and causing a short circuit. However, in order to ensure electrical connection between electrodes of the same polarity, the pin portion must also extend to the outer contour edge of the ceramic insulating layer so that the electrodes of the same polarity are conductive. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0035] Figure 1 A schematic diagram of a partial cross-sectional structure of the piezoelectric driver chip provided in this application;
[0036] Figure 2 A schematic diagram of the planar structure of the first electrode provided in this application;
[0037] Figure 3 A schematic diagram of the planar structure of the second electrode provided in this application;
[0038] Figure 4 A schematic diagram of the planar structure of the third electrode provided in this application;
[0039] Figure 5 A schematic diagram of the planar structure of the fourth electrode provided in this application;
[0040] Figure 6 A schematic diagram of the planar structure of the fifth electrode provided in this application;
[0041] Figure 7 A schematic diagram of the planar structure of the sixth electrode provided in this application;
[0042] Figure 8 A schematic diagram of the three-dimensional structure of the piezoelectric drive stack provided in this application;
[0043] Figure 9 This is a schematic diagram of the planar structure of the printing screen provided in this application.
[0044] Among them, the reference numerals in the figures are:
[0045] 1. Piezoelectric drive stack; 11. Piezoelectric drive chip; 111. Ceramic insulation layer; 1111. First through hole; 112. Electrode; 1121. Pole piece; 1122. Pin; 1123. Second through hole; 12. End surface conductive layer. DETAILED DESCRIPTION
[0046] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.
[0047] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.
[0048] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.
[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.
[0050] like Figure 1 and Figure 8 As shown, the present application provides a piezoelectric driver that utilizes the inverse piezoelectric effect of piezoelectric materials to convert electrical energy into mechanical energy or mechanical motion. The piezoelectric driver includes a plurality of piezoelectric driver stacks 1 stacked in sequence. The driving expansion and contraction amount of the piezoelectric driver is equal to the sum of the driving expansion and contraction amounts of each piezoelectric driver stack 1. The piezoelectric driver stack 1 includes a plurality of piezoelectric driver chips 11 stacked in sequence. The piezoelectric driver chip 11 serves as the minimum functional unit of the piezoelectric driver. The sum of the driving expansion and contraction amounts of each piezoelectric driver chip 11 is equal to the driving expansion and contraction amount of the piezoelectric driver stack 1. The piezoelectric driver chip 11 specifically includes a ceramic insulating layer 111 and an electrode 112. The ceramic insulating layer 111 and the electrode 112 are alternately arranged in sequence, and together constitute the piezoelectric driver chip 11.
[0051] The ceramic insulating layer 111 has a first through-hole 1111, which serves as the center hole of the ceramic insulating layer 111. The electrode 112 includes a pole piece 1121 and a pin 1122. To ensure better insulation at the center hole, the pole piece 1121 has a second through-hole 1123 coaxially arranged with the first through-hole 1111 and having a larger diameter than the first through-hole 1111. Because the diameter of the second through-hole 1123 is larger than the diameter of the first through-hole 1111, a ceramic insulating ring is provided between the edge of the electrode 112 and the edge of the center hole, providing insulation. Current cannot flow across this ceramic insulating ring to conduct to the adjacent electrode 112, thus preventing problems such as short circuits. This ceramic insulating ring replaces the organic insulating layer at the center hole of a conventional piezoelectric actuator. The ceramic insulating ring offers more stable performance than organic insulating layers and is less susceptible to environmental factors such as temperature and humidity. Furthermore, the ceramic insulating ring is smoother and more wear-resistant than organic insulating layers, eliminating the need for complex coating processes.
[0052] In addition, if Figures 2 to 7 As shown, the projection of the pole piece 1121 along the thickness direction is within the projection of the outer contour of the ceramic insulating layer 111. This is also intended to ensure absolute insulation from the adjacent electrode 112 and prevent the pole piece 1121 from contacting the outer edge of the ceramic insulating layer 111 and causing a short circuit. However, to ensure electrical connection between electrodes 112 of the same polarity, the pin portion 1122 must also extend to the outer edge of the ceramic insulating layer 111 to ensure electrical connection between the electrodes 112 of the same polarity.
[0053] like Figure 1 and Figure 8 As shown, in one embodiment of the present application, the electrode 112 includes a positive electrode and a negative electrode, and the positive electrode and the negative electrode are arranged alternately in sequence. The ceramic insulating layer 111 is arranged between the positive electrode and the negative electrode to play an insulating role. At the same time, the ceramic insulating layer 111 generates an inverse piezoelectric effect under the action of the electric field formed by the positive / negative electrodes. To avoid a short circuit between the positive electrode and the negative electrode, the pin portion 1122 of the positive electrode faces one side of the plane of the piezoelectric driver chip 11, and the pin portion 1122 of the negative electrode faces the other side of the plane of the piezoelectric driver chip 11, so that the positive electrode and the negative electrode maintain a safe spacing distance to avoid the occurrence of a short circuit.
[0054] like Figure 1 and Figure 8 As shown, in one embodiment of the present application, the piezoelectric drive stack 1 further includes paired end surface conductive layers 12, which are used to electrically connect the electrodes 112 of the same polarity. Specifically, the paired end surface conductive layers 12 are respectively provided on both sides of the piezoelectric drive stack 1, with one of the paired end surface conductive layers 12 being electrically connected to the positive electrode, and the other of the paired end surface conductive layers 12 being electrically connected to the negative electrode.
[0055] In one embodiment of the present application, the minimum distance between the first through hole 1111 and the second through hole 1123 is greater than 0.01 mm.
[0056] In one embodiment of the present application, the aperture of the first through hole 1111 is in the range of 1 mm to 20 mm.
[0057] The present application also provides a method for manufacturing a piezoelectric actuator, comprising the following steps:
[0058] (1) Preparation of green porcelain tape
[0059] A piezoelectric ceramic powder is selected, wherein the slurry formulation comprises 30 to 85 wt% of ceramic powder and 15 to 70% of organic matter. The organic matter comprises 70 to 90 wt% of a solvent, 5 to 25 wt% of a binder, and 0.5 to 5 wt% of a slurry additive. The ceramic powder and the organic matter are sequentially added to a ball mill container and ball milled for 5 to 80 hours to obtain a slurry. The slurry is then tape-casted to obtain a 20-80 μm green ceramic tape, and holes are punched into the green ceramic tape.
[0060] (2) Printed electrodes 112
[0061] The pattern of the electrode 112 is printed on the green porcelain tape. The pattern of the electrode 112 can be a circular ring, a square ring or other geometric shapes.
[0062] (3) Preparation of green blocks
[0063] The green porcelain tapes with printed electrodes 112 are stacked one by one for 40 to 200 layers. After reaching a certain thickness, they are pressed into green blocks by isostatic pressing. The total thickness of the green blocks ranges from 1 mm to 5 mm.
[0064] (4) Cutting the green block
[0065] The green block is cut into individual green blocks along the surface cutting lines. The surface size of the individual green blocks can be specifically 8.3 mm x 8.3 mm.
[0066] (5) Opening the center hole
[0067] A center hole is drilled in the center of each green compact using a drilling tool. The smoothness of the inner wall of the center hole should meet the requirements. The diameter of the center hole can be 2.1 mm.
[0068] (6) Debinding and sintering
[0069] Each green body with a central hole is placed in a binder removal furnace and heated at a temperature of 300°C to 600°C for 2 to 100 hours to remove the colloid from the green body. It is then transferred to a sintering furnace, where the electrode 112 and the green porcelain tape are co-fired at a high temperature of 700°C to 1300°C for 0.5 to 5 hours, ultimately forming a ceramic block, i.e., the green body of the piezoelectric driver chip 11. After sintering, the green body has a thickness of approximately 0.8 mm to 4 mm, and the diameter of the central hole is approximately 2 mm.
[0070] (7) Grinding
[0071] The blank of the piezoelectric driving chip 11 is ground into a specified shape and size as required.
[0072] (8) Bonding alignment
[0073] The ground piezoelectric driving chips 11 are bonded one by one to form a piezoelectric driving stack 1 .
[0074] (9) Plating the end surface conductive layer 12
[0075] End surface conductive layers 12 are plated on both ends of the piezoelectric drive stack 1 to conduct the electrodes 112 of the same polarity in the piezoelectric drive stack 1. The material of the end surface conductive layer 12 can be metallic silver.
[0076] (10) Welding leads
[0077] Positive / negative electrode leads are welded to the end surface conductive layer 12 to connect to an external circuit.
[0078] (11) Polarization treatment
[0079] The piezoelectric drive stack 1 with welded leads is placed in silicone oil for polarization treatment.
[0080] In one embodiment of the present application, the step of forming a center hole in each individual green compact can be performed after the debinding and sintering steps. In another embodiment of the present application, the step of forming a center hole in each individual green compact can be performed after the bonding and alignment steps. The specific location of the step of forming a center hole can be adjusted according to product requirements.
[0081] like Figure 9 As shown, in one embodiment of the present application, when printing the electrode 112, a printing screen is used to print the electrode 112 pattern. The printing screen has a plurality of electrode 112 patterns arranged in a rectangular array, and the printing plate transfers the ink holes to the printed object through pressure. The printing screen also has positioning holes 2 and cutting line holes 3 surrounding the outside of the rectangular array. The positioning holes serve as marks or reference points to ensure the alignment accuracy of different layers during alignment. The cutting line serves as the position based on which the block is cut to ensure that the product is cut into units according to the designed size.
[0082] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.
Claims
1. A piezoelectric actuator, characterized in that: include: A plurality of sequentially stacked piezoelectric drive stacks (1), the piezoelectric drive stacks (1) comprising a plurality of sequentially stacked piezoelectric drive chips (11), the piezoelectric drive chips (11) comprising ceramic insulating layers (111) and electrodes (112), the ceramic insulating layers (111) and the electrodes (112) being alternately arranged in sequence; The ceramic insulating layer (111) is provided with a first through hole (1111); the electrode (112) comprises a pole piece portion (1121) and a pin portion (1122); the pole piece portion (1121) is provided with a second through hole (1123) coaxially arranged with the first through hole (1111) and having a diameter larger than that of the first through hole (1111); the projection of the pole piece portion (1121) in the thickness direction is within the projection of the outer contour of the ceramic insulating layer (111), and the pin portion (1122) extends to the edge of the outer contour of the ceramic insulating layer (111).
2. The piezoelectric actuator according to claim 1, wherein The electrode (112) includes a positive electrode and a negative electrode, the positive electrode and the negative electrode are alternately arranged in sequence, the ceramic insulating layer (111) is arranged between the positive electrode and the negative electrode, the pin portion (1122) of the positive electrode faces one side of the plane of the piezoelectric drive chip (11), and the pin portion (1122) of the negative electrode faces the other side of the plane of the piezoelectric drive chip (11).
3. The piezoelectric actuator according to claim 2, wherein The piezoelectric drive stack (1) further includes end surface conductive layers (12) arranged in pairs, wherein the end surface conductive layers (12) arranged in pairs are respectively arranged on both sides of the piezoelectric drive stack (1), one of the end surface conductive layers (12) arranged in pairs is electrically connected to the positive electrode; and the other of the end surface conductive layers (12) arranged in pairs is electrically connected to the negative electrode.
4. The piezoelectric actuator according to any one of claims 1 to 3, wherein: The minimum distance from the first through hole (1111) to the second through hole (1123) is greater than 0.01 mm.
5. The piezoelectric actuator according to any one of claims 1 to 3, wherein: The aperture of the first through hole (1111) ranges from 1 mm to 20 mm.