Piezoelectric stack clamping device for active vibration reduction of bulkhead

Abstract

The embodiment of the invention discloses a piezoelectric stack clamping device for active vibration reduction of a bulkhead, relates to the technical field of structural vibration control, and can implement faster active control on the vibration response of the bulkhead on the premise that the structure is simple and the stability is high. The device is characterized in that a pair of bases are installed on the bulkhead in a non-punching mode, and the size and the shape of the bottom of each base are matched with the size and the shape of the bulkhead; one end of the piezoelectric stack actuator is fixedly connected with a base of the clamping device through a bearing seat, and the other end of the piezoelectric stack actuator is in threaded connection with the flexible hinge; the flexible hinge is fixedly connected to the inner side of the other base; the piezoelectric stack actuator serves as a source of excitation force, excitation voltage generates displacement response after being input into the piezoelectric stack actuator, the displacement response is transmitted to the clamping device through the flexible hinge, the displacement response is converted into the excitation force under the limitation of the clamping device, and therefore a pair of force which is equal in magnitude and opposite in direction is output to the base, and excitation is formed.

Description

Technical Field

[0001] This invention relates to the field of structural vibration control technology, and in particular to a piezoelectric stack clamping device for active vibration reduction of bulkheads. Background Technology

[0002] Bulkhead vibration is a serious problem in large equipment such as helicopters, airplanes, and ships. Bulkhead vibration and the radiated noise it causes endanger the physical and mental health of the crew and affect the performance and lifespan of the equipment. Traditional vibration reduction methods mainly employ passive vibration control technologies, such as damping technology, vibration isolation of dynamic machinery, and vibration absorption, at the vibration source and critical transmission path. However, active vibration control technology, which can monitor the structural vibration characteristics and respond in a timely manner, has potential advantages such as good effectiveness and strong adaptability, and has already been applied to some extent in vibration and noise control.

[0003] However, due to the complex vibration transmission paths of modern equipment, it is difficult to completely isolate vibration or implement active vibration control at each transmission path. To meet the need for further vibration reduction and noise reduction in practical engineering, directly reducing the vibration response at the end of the vibration transmission path, i.e., at the bulkhead, has become a new approach to vibration reduction and noise reduction. In recent years, with the rapid development of smart materials and manufacturing processes, new types of intelligent actuators with lighter weight, faster response speed, and wider control bandwidth have gained more attention in active vibration control. Among them, piezoelectric stack actuators, which stack multiple layers of piezoelectric ceramic sheets one by one, generate axial driving force by applying voltage to the opposing surfaces in the polarization direction. These actuators have advantages such as high output energy density and wide operating bandwidth, and are increasingly favored in active vibration control.

[0004] However, due to the extremely limited displacement of piezoelectric stack actuators (approximately on the order of micrometers), current research on their applications mainly focuses on precision equipment such as small robots and probes, where they serve as driving elements to output minute displacement responses. Additionally, piezoelectric stacks have been used in vibration isolation devices and reducer struts. However, research on the active control of structural vibration using piezoelectric stacks is limited, and most existing methods employ slotted embedding, bolted connections, or complex structures using multiple wedge-shaped blocks pressing against each other for fixation. These methods suffer from problems such as damaging the original structure at the installation location, complex installation structures, poor stability, and high nonlinearity of the response.

[0005] Therefore, how to improve a simple and stable clamping device to better fix the piezoelectric stack actuator, so as to implement faster active control of the bulkhead vibration response as an actuator unit in the active control system, has become a research topic. Summary of the Invention

[0006] The embodiments of the present invention provide a piezoelectric stack clamping device for active vibration reduction of bulkheads, which can implement faster active control of bulkhead vibration response while meeting the requirements of simple structure and high stability.

[0007] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0008] A piezoelectric stack clamping device for active vibration reduction of bulkheads includes: a piezoelectric stack actuator (5) and a clamping device, wherein the clamping device includes: a base (1), a thrust bearing (3), a bearing seat (4), and a flexible hinge (7); a pair of bases (1) are mounted on the bulkhead in a non-drilling manner, and the bottom size and shape of the bases (1) match the size and shape of the bulkhead; one end of the piezoelectric stack actuator (5) is fixedly connected to the base (1) of the clamping device through the bearing seat (4), and the other end is connected to the flexible hinge. The flexible hinge (7) is fixed to the inside of another base (1) by a threaded connection. The other end of the flexible hinge (7) is fixedly connected to the piezoelectric stack actuator (5). The piezoelectric stack actuator (5) serves as the source of excitation force. After the excitation voltage is input to the piezoelectric stack actuator (5), a displacement response is generated and transmitted to the clamping device through the flexible hinge (7). Under the restriction of the clamping device, the displacement response is converted into an excitation force, thereby outputting a pair of forces of equal magnitude and opposite direction to the base (1) and forming an excitation.

[0009] The piezoelectric stack clamping device for active bulkhead vibration reduction provided in this invention, compared with existing embedded-wedge and base-wedge clamping methods, uses a thrust bearing to transmit preload, and adjusts the preload by adjusting the bearing seat with bolts. This results in a simple and lightweight structure, allowing for the use of standard parts for easy maintenance and replacement. Compared with existing base-bolt clamping methods, this piezoelectric stack clamping device avoids the problems of limited preload loading and nonlinear response caused by limited thread stroke. While maintaining structural simplicity and high stability, it enables faster active control of bulkhead vibration response. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1(a) is a schematic diagram of the existing piezoelectric stack actuator clamping method (embedded-wedge block clamping);

[0012] Figure 1(b) is a schematic diagram of the existing piezoelectric stack actuator clamping method (base-wedge block clamping);

[0013] Figure 2 This is a schematic diagram of the main structure of the thrust bearing clamping device provided in an embodiment of the present invention;

[0014] Figure 3(a) is a schematic diagram of the thrust bearing and bearing housing provided in an embodiment of the present invention;

[0015] Figure 3(b) is a schematic diagram of the double-ear stop pad provided in an embodiment of the present invention;

[0016] Figure 4 This is a schematic diagram of a piezoelectric stack actuator provided in an embodiment of the present invention;

[0017] Figure 5 This is a schematic diagram of the piezoelectric stack clamping device provided in an embodiment of the present invention;

[0018] Figure 6 This is a schematic diagram of the assembly of the piezoelectric stack clamping device provided in an embodiment of the present invention on the bulkhead;

[0019] Figure 7 This is a structural schematic diagram of the left base component provided in an embodiment of the present invention;

[0020] Figure 8 This is a structural schematic diagram of the right base component provided in an embodiment of the present invention;

[0021] Figure 9 This is a schematic diagram of the bearing housing component structure provided in an embodiment of the present invention;

[0022] Figure 10 This is a schematic diagram of the maximum dynamic output force-frequency curve of the piezoelectric stack provided in an embodiment of the present invention;

[0023] Figure 11 This is a schematic diagram of the test results for single-input single-output active control provided in an embodiment of the present invention;

[0024] The numbers in the attached diagram represent: base (1), left base (1-1), right base (1-2), thrust bearing (3), bearing seat (4), inner part of bearing seat (4-1), outer part of bearing seat (4-2), piezoelectric stacked actuator (5), positioning plate (6), flexible hinge (7), bolt (8), double-eared locking washer (9), and anti-loosening nut (10). Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of the present invention means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0026] The design purpose of this embodiment is to solve two major challenges faced by piezoelectric stack actuators in practical engineering applications: First, to design a simpler and lighter structure to apply preload to both ends of the piezoelectric stack actuator, thereby converting the strain and small displacement response of the piezoelectric stack actuator into dynamic force and acceleration response output, ensuring active control performance; Second, to ensure a stable connection between components in a vibration environment, reduce the nonlinearity of acceleration response, and improve the reliability, stability, and durability of the actuator.

[0027] Currently, the commonly used displacement limiting method for piezoelectric stack actuators is to slot, embed the piezoelectric stack, and fix it by the compression of two wedge blocks, as shown in Figure 1(a). This method has high clamping stiffness and good stability, but the lever arm is relatively short, the excitation force is mainly an in-plane load, and it is not suitable for structures such as bulkheads and pipelines that cannot tolerate slotting. To address this issue, a base is added at the installation position, and a clamping structure with wedge blocks is also used at both ends of the base, as shown in Figure 1(b). The problem with this method is that the clamping structure is complex, the stability is poor, and it shows insufficient mid-to-high frequency actuation capability in bulkhead tests. Some solutions also propose using a base and bolts to install the piezoelectric stack actuator on the pipeline for pipeline vibration reduction, but experiments show that directly using a base and bolts to fix the piezoelectric stack actuator leads to high response nonlinearity. The problem with this clamping method is that, due to the limited stroke of the bottom thread of the piezoelectric stack actuator, when the bolt is screwed to the bottom of the thread, continuing to screw the bolt in will cause the piezoelectric stack to bear torsional loads. This not only fails to apply preload effectively, but may even damage the adhesive layer inside the piezoelectric stack.

[0028] The design concept of this embodiment is as follows: a thrust bearing is used to replace the wedge block, and the bottom of the bearing housing is connected by a thread. The bearing housing is pressed inward by screwing in bolts, and the preload is transmitted through the thrust bearing. Finally, anti-loosening designs such as anti-loosening nuts and double-eared locking washers are added to maintain stable loading of the preload in a vibration environment, improving the reliability, stability, and durability of the actuator. The final design results in a simple, lightweight, and robust piezoelectric stack clamping device. The device structure diagram is shown below. Figure 2 As shown, it includes: a piezoelectric stacked actuator (5) and a clamping device, the clamping device including: a base (1), a thrust bearing (3), a bearing seat (4) and a flexible hinge (7); the base (1) is installed on the bulkhead in a non-drilling manner, and the bottom size and shape of the base (1) match the size and shape of the bulkhead; the base (1) is installed on the bulkhead structure, since the surface of the bulkhead is mostly curved and cannot be drilled, the bottom of the base (1) needs to be processed with a certain arc according to the size of the bulkhead, and finally fixed to the surface of the bulkhead by welding or high-strength adhesive.

[0029] One end of the piezoelectric stack actuator (5) is fixedly connected to the base (1) of the clamping device via a bearing seat (4); one end of the flexible hinge (7) is fixedly connected to one side of the base (1), and the other end of the flexible hinge (7) is fixedly connected to the piezoelectric stack actuator (5); the piezoelectric stack actuator (5) serves as the source of excitation force. After the excitation voltage is input to the piezoelectric stack actuator (5), a displacement response is generated and transmitted to the clamping device via the flexible hinge (7). Under the constraint of the clamping device, the displacement response is converted into an excitation force, thereby outputting a pair of forces of equal magnitude and opposite direction to the base (1) and forming excitation. Among them, the piezoelectric stack actuator (5) is the source of excitation force. After the excitation voltage is input, the piezoelectric stack generates a displacement response. Under the constraint of the clamping structure, the displacement loss is converted into an excitation force, outputting a pair of forces of equal magnitude and opposite direction to the base (1), which excite the installation location on the bulkhead in the form of bending moment. By utilizing the thrust transmission capability and rotational freedom of the thrust bearing, the piezoelectric stack can be installed and pre-tightened by screwing the bearing base into the thread, making the overall structure simpler and more stable and reliable than the traditional installation method.

[0030] In this embodiment, a threaded through hole is provided on the outer surface of the left base (1-1), and the bolt (8) passes through the threaded through hole; a threaded hole of a certain depth is provided on the inner surface of the right base (1-2), and a stud is installed in the threaded hole. One end of the flexible hinge (7) is fixedly connected to the stud by a lock nut (10). The flexible hinge (7) is fixedly connected to the right base (1-2) to transmit the piezoelectric stack output force to the right base (1). The flexible hinge (7) can compensate for the bending moment of the piezoelectric stack, prevent the piezoelectric stack actuator (5) from being damaged by excessive bending moment, and extend the service life and stability of the piezoelectric stack actuator (5).

[0031] In this embodiment, one end of the piezoelectric stack actuator (5) is connected to the bearing seat (4), and the bearing seat (4) is fixedly connected to the base (1) of the left base (1-1) clamping device; the bearing seat (4) is installed on the end of the bolt (8) that extends out of the left base (1-1) by another anti-loosening nut (10). The end of the bolt (8) that extends out of the left base (1-1) is also equipped with a double-eared stop washer (9).

[0032] In the bearing housing (4), the thrust bearing (3) is installed between the inner part (4-1) and the outer part (4-2) of the bearing housing; the inner part (4-1) of the bearing housing is fixedly connected to one end of another anti-loosening nut (10) and bolt (8) extending out of the inner side of the left base (1-1); the outer part (4-2) of the bearing housing is fixedly connected to one end of the piezoelectric stack actuator (5). Among them, the thrust bearing (3) and the bearing housing (4) transmit the output force of the piezoelectric stack to the left base (1). The detailed structure is shown in Figure 3 (a). The inner part (4-1) of the left bearing housing is fixedly connected to the bolt (8) passing through the threaded hole of the base (1), and the outer part (4-2) of the right bearing housing is fixedly connected to the bottom of the piezoelectric stack by threads.

[0033] By tightening the bolt (8), the inner part (4-1) of the bearing housing is squeezed inward to form a preload. The preload is applied to the piezoelectric stack actuator (5) via the thrust bearing (3) and the outer part (4-2) of the bearing housing. In practical applications, the preload is adjusted by screwing the bolt (8) in, thereby ensuring that the displacement of both ends of the piezoelectric stack is strictly limited during the operation of the active vibration damping device, and the excitation force output is stable. After the preload is applied, the position of the bolt (8) is fixed by the anti-loosening device to maintain the stable application of the preload.

[0034] Furthermore, a keyway is machined on the left base (1-1); when installing the double-eared stop washer (9), the long ear is bent downwards and inserted into the keyway of the left base (1-1); after the preload is applied, the short ear of the double-eared stop washer (9) is bent to fit the bolt (8). The components are connected by bolts (8), and after the connection is secure, the device is treated to prevent loosening by using anti-loosening nuts (10), thread sealant, double-eared stop washer (9), etc. As shown in Figure 3(b), the double-eared stop washer (9) is bent downwards and inserted into the keyway of the left base (1-1) when installed. After the preload is applied, the short ear can be bent to fit the bolt (8), thereby preventing the bolt (8) from loosening.

[0035] Optionally, the positioning plate (6) is threadedly connected to the base (1) to assist in positioning the distance between the left base (1-1) and the right base (1-2) when the piezoelectric stack actuator (5) is not installed. The positioning plate (6) has high rigidity and can assist in positioning the distance between the base (1) when the piezoelectric stack actuator (5) is not installed, ensuring that the arc at the bottom of the base (1) fits tightly against the bulkhead. The piezoelectric stack actuator (5) can be disassembled after installation.

[0036] In practical applications, the Pst150 / 14 / VS20 type piezoelectric actuator can be selected as the piezoelectric stack actuator (5), according to Figure 6-9 The process of machining each component as shown, preparing several standard parts, and installing the piezoelectric stack actuator (5) into the clamping device includes:

[0037] Install the left base (1-1) and the right base (1-2) on the positioning plate (6), and use the positioning plate (6) to fix the distance between the left base (1-1) and the right base (1-2). Then, use welding or adhesive to attach the base (1) to the bulkhead and securely connect it.

[0038] Bend the long ear of the double-ear retaining washer (9) downward and insert it into the keyway on the outside of the left base (1-1). Screw the bolt (8) into the threaded through hole of the left base (1-1) and screw the bolt (8) into the anti-loosening nut (10). Then install the inner part of the bearing housing (4-1) on the end of the bolt (8). At this time, the stability of the threaded connection can be improved by using low viscosity thread glue.

[0039] The flexible hinge (7) and the bearing housing external part (4-2) are respectively installed at both ends of the piezoelectric stack actuator (5) by threaded connection. The stability of the threaded connection can be improved by low viscosity thread glue. The flexible hinge (7) is fixedly connected to the right base (1-2) by thread.

[0040] Install the thrust bearing (3) in the inner part (4-1) of the bearing housing, and then slowly screw in the bolt (8) until the outer part (4-2) of the bearing housing fits tightly with the bearing; wherein, the bolt (8) is screwed in further by using a torque wrench to apply a preload; after the preload is applied, tighten the anti-loosening nut (10) and bend the short ear of the double-eared locking washer (9) upward to be close to the surface of the bolt (8);

[0041] After removing the positioning plate (6), checking the connections between the components, and inspecting the piezoelectric stacked actuator (5), it can be used. To verify the actual effect of the clamping device and the actual operating capability of the actuator in the active control system, a series of performance tests and active control tests were carried out. Some results are as follows: Figure 10-11 As shown.

[0042] This scheme involves the field of active vibration control. To ensure the control effect, the output force of the actuator (clamping device and) needs to generate sufficient acceleration response on the bulkhead. The frequency range, nonlinearity, and acceleration response characteristics of the output force are also important parameters affecting the active control effect. This requires the active vibration damping device to make full and reasonable use of the displacement response of the piezoelectric stack actuator (5). The actual actuation capability of the active vibration damping device in the active control system should be verified by active control test on the bulkhead model. The actuator performance of the designed and developed intelligent structure active vibration damping device is tested, including output force amplitude, output force frequency range, output force nonlinearity, acceleration response level and response distribution. Active control test is carried out to gradually verify the actual performance of the active vibration damping device based on the control effect, and the problems and defects of the active vibration damping device in engineering practice are summarized.

[0043] For example, the device in this solution can be fixed to the bulkhead of large equipment such as helicopters, airplanes, and ships, and its displacement response can be converted into bending moment output. This improves the stability and reliability of the piezoelectric stack under long-term, harsh working conditions and reduces the nonlinearity of the output. The device can be applied to the field of active vibration and noise control, and when paired with a piezoelectric stack actuator, it can serve as an actuator unit in an active control system to actively control the bulkhead vibration response.

[0044] Compared to existing embedded-wedge and base-wedge clamping methods, this piezoelectric stack clamping device uses a thrust bearing to transmit preload, and the preload is adjusted by adjusting the bearing housing with bolts. The structure is simple and lightweight, and standard parts can be used directly for easy maintenance and replacement. Compared to existing base-bolt clamping methods, this piezoelectric stack clamping device avoids the problems of limited preload loading and nonlinear response caused by limited thread stroke. Furthermore, existing piezoelectric stack clamping methods rely solely on thread self-locking for preload, which is prone to loosening under vibration. This design incorporates double-ear locking washers and self-locking nuts to prevent loosening, improving the stability and reliability of the device.

[0045] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A piezoelectric stack clamping device for active damping of a bulkhead, characterized by The utility model relates to a kind of piezoelectric stack actuator (5) and clamping device, the clamping device includes: base (1), thrust bearing (3), bearing seat (4) and flexible hinge (7); The base (1) is installed on the bulkhead by non-punching mode, the size and shape of the bottom of the base (1) are matched with the size and shape of the bulkhead; One end of the piezoelectric stack actuator (5) is fixedly connected with the base (1) of the clamping device through the bearing seat (4); One end of the flexible hinge (7) is fixedly connected with one side of the base (1), and the other end of the flexible hinge (7) is fixedly connected with the piezoelectric stack actuator (5); The piezoelectric stack actuator (5) is used as the source of exciting force, and after the excitation voltage is input into the piezoelectric stack actuator (5), displacement response is generated and transmitted to the clamping device through the flexible hinge (7), and the displacement response is converted into exciting force under the restriction of the clamping device, so that a pair of forces with equal size and opposite direction are output to the base (1) and exciting is formed. A threaded hole is formed in the outer surface of the left base (1-1), and a bolt (8) passes through the threaded hole; 2. The piezoelectric stack clamp device for active damping of a bulkhead according to claim 1, characterized in that, A threaded hole with a certain depth is formed in the inner surface of the right base (1-2), and a stud is installed in the threaded hole, one end of the flexible hinge (7) is threadedly connected with the stud, and a lock nut (10) is additionally installed to prevent loosening. One end of the piezoelectric stack actuator (5) is connected with the bearing seat (4), and the bearing seat (4) is fixedly connected with the base (1) of the clamping device of the left base (1-1); 3. The piezoelectric stack clamp device for active damping of a bulkhead according to claim 2, wherein, The bearing seat (4) is installed on one end of the bolt (8) protruding from the inner side of the left base (1-1) through another lock nut (10).

4. One end of the bolt (8) protruding from the outer side of the left base (1-1) is also provided with a double-ear stop washer (9). In the bearing seat (4), the thrust bearing (3) is installed between the bearing seat inner portion (4-1) and the bearing seat outer portion (4-2); 5. The piezoelectric stack clamp apparatus for active damping of a bulkhead according to claim 3, wherein, The bearing seat inner portion (4-1) is fixedly connected with the other lock nut (10) and one end of the bolt (8) protruding from the inner side of the left base (1-1); The bearing seat outer portion (4-2) is fixedly connected with one end of the piezoelectric stack actuator (5). By tightening the bolt (8), the bearing seat inner portion (4-1) is pressed inward to form a pre-tightening force, and the pre-tightening force is loaded on the piezoelectric stack actuator (5) through the thrust bearing (3) and the bearing seat outer portion (4-2).

6. The piezoelectric stack clamp apparatus for active damping of a bulkhead according to claim 4, wherein, The left base (1-1) is also machined with a keyway; 7. The piezoelectric stack clamp apparatus for active damping of a bulkhead according to claim 5, wherein, When the double-ear stop washer (9) is installed, the long ear is bent downward and clamped into the keyway of the left base (1-1); After the pre-tightening force is loaded, the short ear of the bent double-ear stop washer (9) is attached to the bolt (8). The positioning plate (6) is threadedly connected with the base (1) and is used to assist in positioning the distance between the left base (1-1) and the right base (1-2) when the piezoelectric stack actuator (5) is not installed.

8. The piezoelectric stack clamp apparatus for active damping of a bulkhead according to claim 5, wherein, The process of installing the piezoelectric stack actuator (5) into the clamping device includes:

9. Piezoelectric stack clamping device for active damping of a bulkhead according to any of claims 1 to 7, characterized in that The left base (1-1) and the right base (1-2) are installed on the positioning plate (6), the distance between the left base (1-1) and the right base (1-2) is fixed by means of the positioning plate (6), and the base (1) is attached to and stably connected with the bulkhead by welding or gluing; ​ Bend the long ears of the double-ear stop washer (9) downward and clamp them into the keyway outside the left base (1-1), screw the bolt (8) into the threaded hole of the left base (1-1), and screw the bolt (8) into the lock nut (10), then install the bearing seat inner part (4-1) at the end of the bolt (8); Install the flexible hinge (7) and the bearing seat outer part (4-2) at both ends of the piezoelectric stack actuator (5) respectively through threaded connection, and fix the flexible hinge (7) to the right base (1-2) through threaded connection; Install the thrust bearing (3) in the bearing seat inner part (4-1), then slowly screw the bolt (8) into the bearing seat outer part (4-2) to tightly match the bearing; wherein, continue to screw the bolt (8) by using the torque wrench to load the pre-tightening force; after the pre-tightening force is loaded, tighten the lock nut (10), and bend the short ears of the double-ear stop washer (9) upward to be close to the surface of the bolt (8); Remove the positioning plate (6).

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