A bimorph piezoelectric drive amplification structure

Abstract

The utility model discloses a kind of double piezoelectric drive amplification structures, it is related to precision machining technical field, including base, the inside of base is provided with symmetrical rhombus part, rhombus part middle is piezoelectric ceramic, rhombus part is connected by flexible hinge part and base, one side of base is clamping part, the utility model uses the double piezoelectric ceramic stack of symmetrical layout, by differential drive mode, two-way drive signal is mutually cancelled under common mode disturbance such as thermal expansion, effectively suppresses thermal drift, improves system long-term stability and positioning accuracy.

Description

Technical Field

[0001] This utility model relates to the field of precision machining technology, and in particular to a dual piezoelectric drive amplification structure. Background Technology

[0002] Existing electric drive amplification structures suffer from poor structural stability and displacement amplification accuracy, and are mostly single-voltage driven, which is prone to thermal drift. Therefore, it is necessary to design an amplification structure to solve the above problems.

[0003] In the prior art, patent publication number CN221157207U discloses an online drug mixing and dispensing valve based on piezoelectric ceramics and a compliant amplification structure, including a piezoelectric ceramic actuator, a transmission device, and a nozzle assembly; the transmission device includes a compliant amplification structure, a striker guide sleeve, a cylindrical spring, and a striker; the compliant amplification structure includes a bolt, a horizontal shaft, and a shaped spring; two threaded holes on the hemisphere at the tail end of the horizontal shaft are respectively connected to the threaded sections of two bolts, the optical axis section of the bolt passes through the corresponding through hole of the housing, and the tail end of the horizontal shaft is in contact with the inner wall of the housing; the horizontal shaft is hinged to the piezoelectric ceramic actuator near the tail end and connected to the housing through two parallel shaped springs; the hemisphere at the head end of the horizontal shaft contacts the top cover of the striker. The electric drive structure of this patent has poor stability. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that most existing electric drive structures are single-piezoelectric drives, which are prone to thermal drift. This invention adopts a symmetrical layout of dual piezoelectric ceramic stacks, and achieves fast response and displacement amplification through differential drive, while offsetting the thermal drift effect of single drive.

[0005] Another objective of this invention is to solve the problem of significant frictional loss in existing electric drive amplification structures. This invention uses two piezoelectric ceramics installed in parallel and fixed by a flexible hinge to form a differential push-pull structure, which counteracts lateral load and avoids frictional loss in traditional mechanical transmission.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a dual piezoelectric drive amplification structure, comprising a substrate, wherein symmetrical rhomboid portions are arranged side by side inside the substrate, the middle of the rhomboid portions is a piezoelectric ceramic, the rhomboid portions are connected to the substrate by a flexible hinge portion, and one side of the substrate is a clamping portion.

[0007] Preferably, the rhomboid part includes a long arm and a short arm. The piezoelectric ceramic abuts against the short arm of the rhomboid part at both ends. One end is provided with a pre-tightening member. The piezoelectric ceramic drives the short arm of the rhomboid part, and the displacement is initially amplified by 3 times through the symmetrical deformation of the rhomboid. The pre-tightening member adopts a disc spring to ensure contact stiffness.

[0008] Preferably, one side of the pre-tightening member has a pre-tightening opening to facilitate tool insertion.

[0009] Preferably, the middle part is located between the two rhomboid parts, and a fixing member is provided on the middle part.

[0010] Preferably, the two sides of the base are side support arms, and the two rhomboid parts are connected to the side support arms by flexible hinges. The output end of the rhomboid part is connected to the side support arm and is connected to the side support arm through a flexible hinge. The displacement is further amplified to 9 times by lever ratio. When the piezoelectric ceramic input displacement is 20μm, the output displacement can reach 180μm with an error of <5%.

[0011] Preferably, the flexible hinge section has a double-arc opening. This reduces stress concentration; the double-arc opening employs an arc-shaped cut design to optimize stress distribution and prevent fatigue fracture. Finite element simulation verification shows a lifespan > 10^8 cycles.

[0012] Preferably, the side support arm has a hollow groove inside, and the two ends of the hollow groove are hollow circles.

[0013] Preferably, one end of the clamping part is a positioning clamping piece, which is fixed by a clamping and positioning fastener. The clamping position of the positioning clamping piece is provided with a V-shaped groove, and the contact surface of the positioning clamping piece is coated with diamond-like carbon (DLC) to reduce the risk of gold wire adhesion. The surface roughness Ra < 10 nm.

[0014] Preferably, one end of the substrate has several support strips, and the several support strips are on the same straight line.

[0015] Preferably, the support bar is provided with a fastener, which is used to fix the entire base.

[0016] Compared with the prior art, the beneficial effects of this utility model are: This utility model adopts a symmetrical layout of dual piezoelectric ceramic stacks, and through differential driving, the two driving signals cancel each other out under common mode disturbances such as thermal expansion, effectively suppressing thermal drift and improving the long-term stability and positioning accuracy of the system.

[0017] This invention employs a flexible hinge fixing structure, which installs two piezoelectric ceramics in parallel to form a differential push-pull structure. It eliminates the need for traditional sliding or rotating pairs, fundamentally eliminating frictional losses and improving energy conversion efficiency and structural lifespan.

[0018] This invention is based on a three-stage lever flexible hinge amplification mechanism with a biomimetic "mantis arm" configuration. It can combine rhomboid hinges, lever principles and multi-stage amplification technology to achieve high magnification of micron-level displacement. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model.

[0020] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0021] Figure 3 This is a top view of the structure of this utility model.

[0022] Figure 4 for Figure 3 Sectional view at point CC.

[0023] Figure 5 for Figure 4 Enlarged view of section B in the middle.

[0024] In the figure: 1. Substrate; 2. Piezoelectric ceramic; 21. Pre-tightening component; 22. Pre-tightening port; 3. Rhomboid part; 31. Short arm of rhomboid part; 32. Long arm of rhomboid part; 33. Flexible hinge part; 34. Double arc opening; 4. Side support arm; 5. Support bar; 51. Fixing component; 6. Hollow groove; 7. Clamping part; 71. Clamping positioning piece; 711. V-groove; 72. Clamping positioning fastener; 8. Middle part. Detailed Implementation

[0025] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. The described embodiments are only some embodiments of this utility model, and not all embodiments.

[0026] Example 1: Refer to Figures 1 to 5 A dual piezoelectric drive amplification structure includes a substrate 1, which is integrally machined to ensure structural rigidity and stability. Two symmetrical rhomboid portions 3 are arranged side-by-side inside the substrate 1, with a piezoelectric ceramic 2 mounted between the rhomboid portions 3. The piezoelectric ceramic 2 is preferably a stacked piezoelectric ceramic, which has high energy density and fast response characteristics. The rhomboid portions 3 are connected to the substrate 1 via flexible hinge portions 33, forming an elastic support. A clamping portion 7 is provided on one side of the substrate 1 for fixing external workpieces or tools. The entire structure adopts a symmetrical layout, with the two rhomboid portions 3 mirror-symmetrical about the centerline of the substrate 1. This design allows for differential drive.

[0027] Each rhomboid portion 3 includes a long rhomboid arm 32 and a short rhomboid arm 31, which are connected by a flexible hinge to form a rhomboid frame. The two ends of the piezoelectric ceramic 2 directly abut against the inner side of the short rhomboid arm 31. A preload 21 is provided at one end of the piezoelectric ceramic 2. The preload 21 uses a disc spring, which provides a constant preload force while ensuring high contact stiffness, preventing the piezoelectric ceramic from loosening during dynamic operation. A preload opening 22 is provided on one side of the preload 21, allowing tools such as screwdrivers or special clamps to be inserted for adjusting the preload force or for maintenance.

[0028] When the piezoelectric ceramic 2 is energized and elongates, it pushes the short arm 31 of the rhomboid part, causing the rhomboid frame to undergo symmetrical deformation. In this embodiment, the magnification factor of the rhomboid part is designed to be 3 times, that is, if the input displacement of the piezoelectric ceramic is 20μm, a displacement of about 60μm can be generated at the output end of the clamping part.

[0029] A middle section 8 is provided between the two rhomboid sections 3. The middle section 8 is part of the base 1 and a fastener 51 is provided on it. The fastener 51 can be a threaded hole or a mounting groove, used to fix the entire structure to the external base by bolts to ensure that there is no overall displacement during operation.

[0030] The base 1 has side support arms 4 on both sides, which are integrally formed with the base 1 and provide the main support rigidity. The ends of the long arms 32 of the two rhomboid parts 3 are connected to the side support arms 4 through flexible hinge parts 33. The flexible hinge parts 33 further amplify the output displacement of the rhomboid parts, and a lever mechanism is formed between the side support arms 4 and the rhomboid parts. According to the lever principle, in this embodiment, the lever ratio is designed to be 3:1, so the secondary amplification factor is 3 times. Combined with the initial amplification of 3 times by the rhomboid parts, the total amplification factor can reach 9 times. For example, when the piezoelectric ceramic 2 is input with a displacement of 20μm, the output displacement of the clamping part 7 can reach 180μm, and the test error is less than 5%. This amplification mechanism has no sliding friction and has high energy conversion efficiency.

[0031] The side support arm 4 has a hollow groove 6 inside, with larger hollow portions at both ends and a narrower middle portion. This design reduces structural weight and optimizes stress distribution, preventing stress concentration that could lead to fatigue fracture. The shape of the hollow groove 6 is topologically optimized to ensure the rigidity of the side support arm during lever movement, and both ends of the hollow groove 6 are hollow circles.

[0032] In this embodiment, the flexible hinge section 33 adopts a double-arc opening 34 design, that is, the hinge cut is two symmetrical arcs, rather than the traditional single arc or right-angle cut. The double-arc opening can significantly reduce the stress concentration factor. Finite element simulation verification shows that its maximum stress is reduced by more than 30% compared with the single arc design, thereby increasing the fatigue life to more than 10^8 cycles.

[0033] The thickness of the flexible hinge section is parametrically optimized to ensure sufficient flexibility while preventing instability or plastic deformation. Simulation analysis shows that under rated load, the maximum stress in the hinge area is less than 50% of the material's yield strength, ensuring long-term reliability.

[0034] The clamping part 7 is located on one side of the base 1 and is used to fix the gold wire. One end of the clamping part 7 is a positioning clamping piece 71, which is fixed by a clamping positioning fastener 72 such as a fine-tuning screw, allowing precise adjustment of the clamping force. The clamping position of the positioning clamping piece 71 is provided with a V-groove 711, which can adapt to cylindrical or spherical workpieces and provide stable clamping. To reduce the risk of adhesion of gold wire or other micro-workpieces, the contact surface of the positioning clamping piece 71 is coated with a diamond-like carbon (DLC) coating. This coating has an extremely low coefficient of friction and high hardness, with a surface roughness Ra of less than 10 nm, ensuring clean operation.

[0035] One end of the base 1 is provided with several support bars 5, which are aligned on the same straight line to form a rigid reference surface. Each support bar 5 is equipped with a fastener 51, which can be a standard threaded hole, used to install the entire structure onto the platform via bolts. The layout of the support bars 5 is based on dynamic analysis to avoid structural resonance and ensure overall stability.

[0036] The flexible hinge 33 creates a lever motion on the side support arm 4, ultimately amplifying the displacement at the clamping part 7. This not only doubles the output displacement but also suppresses thermal drift, because the temperature change has essentially the same effect on the two piezoelectric ceramics, thus canceling each other out at the output end.

[0037] The displacement amplification factor can be calculated using geometric parameters: Let the amplification factor of the rhombus be Kd = 3, and the lever amplification factor be Kl = 3, then the total amplification factor K = Kd × Kl = 9. In actual testing, with an input displacement of 20 μm, the output displacement is 180 ± 5 μm, showing good linearity. The structural stiffness was verified by simulation; the first natural frequency is higher than 500 Hz, meeting the requirements for dynamic applications.

[0038] Example 2: Refer to Figures 1 to 5 A dual-voltage piezoelectric drive amplification structure includes a base 1 serving as an integral support frame. The base 1 is typically machined from a single piece of high-strength metal using wire EDM or precision milling techniques to ensure the relative positional accuracy between components and the overall structural rigidity. Inside the base 1, a symmetrical layout is adopted, with two perfectly mirror-symmetrical rhomboid portions 3 arranged side-by-side. In the central cavity of each rhomboid section 3, a piezoelectric ceramic 2 is installed as a driving element. The piezoelectric ceramic 2 utilizes the inverse piezoelectric effect to convert input electrical energy into micron-level mechanical displacement and enormous thrust, serving as the power source for the entire mechanism. The rhomboid section 3 is not independent; its four vertices are connected to the main frame of the base 1 via precise flexible hinge sections 33. The flexible hinge section 33 is a mechanism that utilizes the elastic deformation of materials to achieve motion transmission and conversion. It replaces traditional sliding bearings, rolling bearings, or rotary hinges, achieving truly frictionless, backlash-free, and lubrication-free motion transmission. This fundamentally eliminates wear, creeping phenomena, and particulate contamination caused by friction, greatly improving the structure's energy conversion efficiency, motion resolution, and service life.

[0039] On one side of the substrate 1, a clamping part 7 is provided. This part is the final output end of the entire amplification structure and is used to fix or clamp external workpieces such as optical lenses, optical fibers, micro probes, etc. In this embodiment, the piezoelectric ceramic 2 selected is NEC-Tokin AE0203D16. This ceramic stack has a compact size of 5mm × 5mm × 18mm and can output a free displacement of 15μm under a driving voltage of 150V. At the same time, it can provide a thrust of up to 800N, ensuring sufficient driving force when driving the amplification mechanism, overcoming the effects of hinge stiffness and load, and ensuring that the output displacement will not be significantly reduced due to load.

[0040] The rhomboid portion 3 is not a simple geometric rhombus, but a flexible mechanism optimized by dynamics and statics. It specifically consists of short arms 31 and long arms 32 of the rhomboid portion. The piezoelectric ceramic 2 is pre-tightened between the short arms 31 on both sides, with its ends precisely abutting against the plane of the short arms. To ensure that the piezoelectric ceramic 2 maintains tight contact with the mechanism under any operating condition, especially during retraction, and to avoid impact and energy loss, a pre-tightening element 21 is provided at one end of the piezoelectric ceramic 2.

[0041] The preload element 21 preferably adopts a Belleville Spring structure. The Belleville Spring has the advantages of high stiffness, small footprint, and the ability to provide constant preload even with minor deformation. It is compressed via an adjusting screw, thereby applying an axial preload to the piezoelectric ceramic 2. This preload not only ensures contact stiffness and improves the linearity of force-displacement transmission, but also keeps the piezoelectric ceramic under compression during operation, improving its tensile strength and fatigue life. When the driving voltage signal is applied to the piezoelectric ceramic 2, its length changes, directly pushing the short arms 31 of the rhomboid portion on both sides. Under the thrust, the entire rhomboid mechanism undergoes elastic deformation; that is, if the piezoelectric ceramic inputs a displacement of 15 μm, the clamping part outputs a displacement of approximately 45 μm.

[0042] To facilitate preload adjustment during assembly and maintenance, a preload port 22 is specially designed on one side of the preload component 21. The preload port 22 is a tool access hole that allows a special wrench or adjusting tool to be inserted to precisely adjust the compression of the disc spring, thereby setting the optimal preload. This design greatly improves the maintainability of the product.

[0043] A central section 8 is provided between the two rhomboid sections 3. This central section 8 is not only a structural dividing area, but more importantly, it serves as a structural reinforcement zone. It enhances the rigidity of the central part of the base 1, suppresses internal coupling vibrations that may occur during dual piezoelectric ceramic drive, and improves the overall modal frequency of the structure. A fastener 51, typically a precision threaded hole, is provided on the central section 8. This fastener 51 is used to rigidly mount the entire enlarged structural module to an external base platform or motion slide.

[0044] When the piezoelectric ceramic 2 is input with a displacement of 20 μm, after two stages of amplification, the final output displacement at the clamping part 7 can reach 180 μm. Through finite element analysis (FEA) and calibration with an actual laser interferometer, the error of this amplification factor can be controlled within 5%, demonstrating excellent linearity and accuracy.

[0045] All flexible hinge sections 33 employ a double-arc opening 34 design. Traditional right-angle or single-arc cut flexible hinges are prone to severe stress concentration at corners, becoming the initiation point of fatigue cracks. The double-arc opening 34 uses symmetrical, continuously varying curvature arc cuts, enabling a more uniform and smooth distribution of stress within the hinge's elastic region, significantly reducing the stress concentration factor. This optimized design maximizes the use of the material's elastic limit, allowing the hinge to operate safely and reliably over a wider range of angles, thereby avoiding fatigue fracture and extending service life. Fatigue life analysis verified using professional finite element simulation software such as ANSYS or Abaqus shows that the double-arc opening 34 structure, under rated load and cyclic loading, achieves a lifespan exceeding 10^8 cycles, fully meeting the requirements for long-term continuous operation of industrial equipment.

[0046] The side support arm 4 has a hollow groove 6 inside. The design of this hollow groove 6 is not a simple hollowing out, but rather it is the result of topology optimization calculations, with larger hollow portions at both ends and a thinner middle area. This design achieves scientific weight reduction while reducing stress concentration.

[0047] One end of the clamping part 7 is a positioning clamping piece 71. The positioning clamping piece 71 is securely fixed to the output end of the side support arm 4 by clamping positioning fasteners 72, such as miniature hexagonal screws. A V-groove 711 is machined on the clamping position of the positioning clamping piece 71. The V-groove is a self-centering structure, particularly suitable for clamping linear workpieces such as gold wires, optical fibers, or cylindrical workpieces such as microshafts and probes. It can automatically correct the workpiece center, providing a stable and highly repeatable clamping effect. Furthermore, the contact surfaces of the positioning clamping piece 71, especially the surface of the V-groove, are coated with a diamond-like carbon (DLC) coating. The DLC coating has extremely high hardness, an extremely low coefficient of friction, and excellent chemical inertness. In applications such as semiconductor wire bonding, this design effectively reduces the risk of adhesion between the gold wire and the clamping piece; at the same time, the smooth surface roughness Ra < 10 nm ensures that precision workpieces will not be scratched.

[0048] One end of the base 1 is designed with several support bars 5, which provide sturdy support while their flexibility helps to isolate some vibrations from the mounting base. The support bars 5 are also provided with fasteners 51, usually through holes or threaded holes, which work together with the fasteners 51 in the middle part 8 to rigidly fix the entire base 1 to the external device with multiple screws, ensuring absolute stability during operation.

[0049] This invention employs a symmetrical dual piezoelectric ceramic differential drive principle, cleverly transforming common-mode disturbances such as thermal expansion into mutually canceling internal effects, greatly suppressing thermal drift. This allows the system to maintain extremely high positioning accuracy and stability even during long-term continuous operation. The fully flexible hinge structure completely eliminates traditional sliding and rotating pairs, fundamentally eliminating friction, wear, and clearance problems. This not only improves energy conversion efficiency but also extends the structural lifespan to tens or even hundreds of millions of cycles, resulting in extremely low maintenance costs. Based on a biomimetic "mantis arm" configuration, it innovatively integrates two mechanisms: rhombic hinge amplification and lever amplification, forming a highly efficient three-stage amplification mechanism. This mechanism combines first-stage rhombic amplification with second-stage lever amplification, achieving high-magnification, linear amplification from micron-level input displacement to hundreds of micron-level output stroke within a compact space. This meets the needs of numerous applications for large-stroke precision drive. Through integrated structural design, stress-optimized dual-circular-arc flexible hinges, and scientific lightweighting, a high resonant frequency is achieved while ensuring structural rigidity and load-bearing capacity. This gives the mechanism excellent dynamic response characteristics, enabling it to handle high-speed, high-precision positioning tasks.

[0050] For those skilled in the art, the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention.

Claims

1. A dual piezoelectric driven amplification structure, characterized in that, The device includes a substrate, inside which are arranged symmetrical rhomboid portions. The center of each rhomboid portion is a piezoelectric ceramic. The rhomboid portions are connected to the substrate by a flexible hinge portion. One side of the substrate is a clamping portion. Each rhomboid portion includes a long arm and a short arm. The two ends of the piezoelectric ceramic abut against the short arm of the rhomboid portion, and one end is provided with a pre-tightening element.

2. The dual piezoelectric drive amplification structure according to claim 1, characterized in that, One side of the pre-tightening component is the pre-tightening port.

3. The dual piezoelectric drive amplification structure according to claim 1 or 2, characterized in that, The middle section is located between the two rhomboid parts, and a fixing component is provided on the middle section.

4. A dual piezoelectric drive amplification structure according to claim 1 or 2, characterized in that, The base has side support arms on both sides, and the two rhomboid parts are connected to the side support arms by flexible hinge parts.

5. The dual piezoelectric drive amplifier structure according to claim 1, characterized in that, The flexible hinge section has a double-arc opening.

6. The dual piezoelectric drive amplification structure according to claim 4, characterized in that, The side support arm has a hollow groove inside, and the two ends of the hollow groove are hollow circles.

7. The dual piezoelectric drive amplifier structure according to claim 1, characterized in that, One end of the clamping part is a positioning clamping piece, which is fixed by a clamping and positioning fastener. A V-shaped groove is provided on the clamping position of the positioning clamping piece.

8. A dual piezoelectric drive amplification structure according to claim 1 or 7, characterized in that, One end of the substrate consists of several support bars, which are aligned on the same straight line.

9. The dual piezoelectric drive amplifier structure according to claim 8, characterized in that, The support bar is equipped with fasteners.

Images