Magnetic type wind power bolt piezoelectric sensing device

Abstract

The utility model relates to wind power generation equipment key connecting part nondestructive testing technical field especially relates to magnetic attraction type wind power bolt piezoelectric sensing device, including piezoelectric ceramic sheet, magnetic attraction probe and portable axial force appearance, piezoelectric ceramic sheet is fixed in bolt end face and completes sound electricity conversion, and magnetic attraction probe realizes detachable connection through magnetic adsorption and guarantees the stability of electric contact, and portable axial force appearance integrates ultrasonic wave excitation module and chronograph for measuring propagation time change amount, the utility model solves the technical problem that traditional ultrasonic probe structure is heavy, and installation needs to destroy anticorrosive layer and is difficult to adapt to the narrow space, through nondestructive installation, quick magnetic attraction connection and integration processing, improve the detection efficiency and measurement accuracy, avoid secondary damage, adapt to the operation and maintenance demand of wind turbine generator unit.

Description

Technical Field

[0001] This utility model relates to the field of non-destructive testing technology for key connecting components of wind power generation equipment, and in particular to a magnetic wind power bolt piezoelectric sensing device. Background Technology

[0002] High-strength wind turbine bolts are high-strength fasteners used for critical structural connections in wind turbine generator sets. They are made of high-quality alloy steel and undergo heat treatment to enhance their mechanical properties, meeting the requirements of long-term operation of wind turbine generator sets under complex wind load environments. Because wind turbines are subjected to alternating dynamic loads and vibration impacts during operation, the bolts must possess high tensile strength and excellent fatigue resistance. Applying precise preload generates sufficient friction at the connection interface, effectively transferring loads and preventing loosening or breakage, thus ensuring the stability of the overall structure.

[0003] Existing ultrasonic testing technology for high-strength bolts in wind turbines suffers from the following technical challenges: Firstly, the existing ultrasonic probes are bulky, requiring grinding of the bolt end face and damage to the anti-corrosion layer during installation to achieve electrical connection. Secondly, the large probe size makes them unsuitable for the confined spaces of critical connection points in wind turbines, such as blade root bolts, leading to cumbersome and time-consuming testing operations. Thirdly, unstable ultrasonic signal transmission significantly reduces measurement accuracy, and damage to the anti-corrosion layer introduces corrosion risks, causing secondary structural damage to the bolts. For instance, in on-site testing scenarios for wind turbine blade root bolts, maintenance personnel using existing probes after climbing the tower face low testing efficiency and fluctuating measurement results due to limited space and installation difficulties. This makes it difficult to accurately identify early loosening, and repeated installation and disassembly further wear down the bolt surface, increasing the risk of fatigue failure. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a magnetic piezoelectric sensing device for wind turbine bolts. This device solves the technical problems of low detection efficiency, insufficient measurement accuracy, and susceptibility to secondary damage caused by the bulky structure of existing ultrasonic probes, the need to damage the anti-corrosion layer of the bolts during installation, and the difficulty in adapting to the confined space of wind turbine units.

[0005] To solve the above-mentioned technical problems, the specific contents of this utility model are as follows: This utility model provides a magnetically attached piezoelectric sensing device for wind turbine bolts, comprising: A piezoelectric ceramic sheet is fixed to the end face of the bolt being tested. A magnetic probe is detachably connected to the piezoelectric ceramic sheet; A portable axial force meter, connected to the magnetic probe via a cable, integrates an ultrasonic excitation module and a timer; The piezoelectric ceramic sheet is used to complete the acoustic-electric conversion, the magnetic probe is used to ensure quick assembly and disassembly and electrical connection stability, and the portable axial force meter is used to excite ultrasonic waves and measure the change in propagation time.

[0006] Furthermore, in the magnetic piezoelectric sensing device for wind turbine bolts described in this utility model, the piezoelectric ceramic sheet is attached to the end face of the bolt, the magnetic probe covers the piezoelectric ceramic sheet and is fixed by magnetic adsorption, and the portable axial force meter is externally connected to the magnetic probe. Furthermore, in the magnetic wind power bolt piezoelectric sensing device of this utility model, the central circular area of ​​the piezoelectric ceramic sheet serves as the positive electrode, and the edge annular area is connected to the back surface as the negative electrode.

[0007] Furthermore, in the magnetic suction type piezoelectric sensing device for wind turbine bolts described in this utility model, the magnetic suction probe includes a ring magnet, a spring pin, and a ring metal sheet. The spring pin contacts the positive electrode of the piezoelectric ceramic sheet, and the ring metal sheet contacts the negative electrode of the piezoelectric ceramic sheet.

[0008] Furthermore, in the magnetic wind turbine bolt piezoelectric sensing device of this utility model, the piezoelectric ceramic sheet is fixed to the end face of the bolt being detected by an adhesive layer, and the adhesive layer covers the back of the piezoelectric ceramic sheet, so that the piezoelectric ceramic sheet and the bolt end face are connected; the positive and negative electrodes of the piezoelectric ceramic sheet are respectively insulated and isolated from the bolt end face through the conductive area on the adhesive layer.

[0009] Furthermore, in the magnetic suction type piezoelectric sensing device for wind turbine bolts described in this utility model, the annular magnet, spring pin, and annular metal sheet in the magnetic suction probe are arranged in a multi-layer stacked structure: the annular metal sheet is located at the bottom layer, facing the piezoelectric ceramic sheet; the annular magnet is stacked on top of the annular metal sheet; the spring pin is vertically arranged in the central hole of the annular magnet and can elastically extend and retract through the annular magnet to contact the positive electrode of the piezoelectric ceramic sheet.

[0010] Furthermore, in the magnetic wind turbine bolt piezoelectric sensing device of this utility model, the bottom of the outer shell of the magnetic probe is provided with an annular groove, which is used to accommodate and limit the edge of the piezoelectric ceramic sheet; the tip of the spring pin protrudes from the bottom of the outer shell and forms point contact with the positive electrode of the piezoelectric ceramic sheet; the annular metal sheet is flush with the bottom of the outer shell and forms surface contact with the negative electrode of the piezoelectric ceramic sheet.

[0011] The beneficial effects of this utility model are: This invention avoids damage to the anti-corrosion layer of bolts by using an adhesive layer to fix the piezoelectric ceramic sheet. The magnetic attraction of the magnetic probe's ring magnet enables quick installation and removal. The spring pin elastically contacts the positive electrode of the piezoelectric ceramic sheet to form a point contact, while the ring metal sheet surface contacts the negative electrode to ensure electrical connection stability. The portable axial force meter integrates an ultrasonic excitation module and a timer to achieve high-precision propagation time measurement. The overall structure is compact and adaptable to the narrow space of wind turbine units. The continuous testing process improves efficiency, reduces signal fluctuations and secondary damage, and extends the service life of bolts. Attached Figure Description

[0012] To more clearly illustrate the technical solution of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the structure of this utility model.

[0014] Figure 2 This is a schematic diagram illustrating the application scenario of this utility model.

[0015] Illustration: 1-Piezoelectric ceramic sheet, 2-Magnetic probe, 21-Ring magnet, 22-Spring pin, 23-Ring metal sheet, 3-Portable axial force meter. Detailed Implementation

[0016] To make the technical solution of this utility model clearer, the present utility model will be clearly and completely described below with reference to specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. The present utility model provided by various embodiments will be described in detail below with reference to the accompanying drawings. To better understand the purpose of this utility model, it will be described in further detail below.

[0017] Please see Figure 1 as well as Figure 2 The magnetic piezoelectric sensing device for wind turbine bolts provided by this utility model includes: Piezoelectric ceramic sheet 1 is fixed to the end face of the bolt being tested; The magnetic probe 2 is detachably connected to the piezoelectric ceramic sheet 1; The portable axial force meter 3 is connected to the magnetic probe 2 via a cable and integrates an ultrasonic excitation module and a timer. The piezoelectric ceramic sheet 1 is used to complete the acoustic-electric conversion, the magnetic probe 2 is used to ensure quick disassembly and assembly and electrical connection stability, and the portable axial force meter 3 is used to excite ultrasonic waves and measure the change in propagation time.

[0018] This utility model provides a magnetically attached piezoelectric sensing device for wind turbine bolts, which achieves rapid and high-precision detection of the axial force of high-strength wind turbine bolts through structural innovation. The device consists of three core components: a piezoelectric ceramic plate 1, a magnetically attached probe 2, and a portable axial force meter 3. These components work together through physical connections to form a complete detection chain. The piezoelectric ceramic plate 1 is fixed to the bolt end face to handle the acoustic-electric conversion, the magnetically attached probe 2 provides a detachable connection to ensure signal stability, and the portable axial force meter 3 processes the ultrasonic signal and outputs the measurement results.

[0019] The piezoelectric ceramic sheet 1 features a miniaturized design, directly attaching to the end face of the bolt being tested and permanently fixed via an adhesive layer. The electrode structure of the piezoelectric ceramic sheet 1 employs a fully flanged design, with the central circular area serving as the positive electrode and the edge annular area connected to the back surface as the negative electrode. This electrode layout ensures the stability of ultrasonic signal transmission. The adhesive layer covers the entire back surface of the piezoelectric ceramic sheet 1, creating a seamless connection between the piezoelectric ceramic sheet 1 and the bolt end face. Simultaneously, insulating material isolates the positive and negative electrodes from the bolt substrate, preventing short-circuit risks.

[0020] The magnetic probe 2 comprises three sub-assemblies: a ring magnet 21, a spring pin 22, and a ring metal plate 23, assembled using a multi-layer stacked structure. The ring metal plate 23 is located at the bottom of the magnetic probe 2, directly facing the negative electrode of the piezoelectric ceramic plate 1 to form surface contact. The ring magnet 21 is stacked above the ring metal plate 23, generating magnetic attraction to fix the probe position. The spring pin 22 vertically penetrates the central hole of the ring magnet 21, elastically extending and contracting to contact the positive electrode of the piezoelectric ceramic plate 1 to form point contact. The bottom of the magnetic probe 2 housing has an annular groove for precisely limiting the installation position of the piezoelectric ceramic plate 1, and the elastic stroke of the spring pin 22 compensates for unevenness at the bolt end face.

[0021] The portable axial force meter 3 connects to the magnetic probe 2 via a shielded cable and integrates an ultrasonic excitation module and a high-precision timer. The ultrasonic excitation module generates a megahertz frequency electrical signal, which is transmitted to the magnetic probe 2 via the cable; the high-precision timer records the change in the propagation time of the ultrasonic wave in the bolt, and the data processing module calculates the axial force attenuation state. The portable axial force meter 3 features a lightweight design for easy carrying and operation in the field.

[0022] When the device is in operation, maintenance personnel first attach the piezoelectric ceramic sheet 1 to the bolt end face to complete the sensor deployment. During testing, the magnetic probe 2 is attached to the surface of the piezoelectric ceramic sheet 1, the annular magnet 21 provides stable holding force, and the spring pin 22 and the annular metal sheet 23 automatically establish an electrical path. The portable axial force meter 3 excites an ultrasonic signal, which is converted into a mechanical wave by the piezoelectric ceramic sheet 1 and propagates in the bolt. The echo signal returns through the same path and is converted into an electrical signal. The timer measures the change in acoustic time, and the data is uploaded to the monitoring system after lightweight processing. The entire testing process is completed within seconds, without damaging the bolt's anti-corrosion layer, making it suitable for the confined working environment of wind turbine units.

[0023] Specifically, in the magnetic wind turbine bolt piezoelectric sensing device of this utility model, the piezoelectric ceramic sheet 1 is attached to the end face of the bolt, the magnetic probe 2 covers the piezoelectric ceramic sheet 1 and is fixed by magnetic adsorption, and the portable axial force meter 3 is externally connected to the magnetic probe 2.

[0024] The piezoelectric ceramic sheet 1 is fixed to the end face of the bolt being tested via an adhesive layer. This adhesive layer, made of epoxy resin, covers the entire back of the piezoelectric ceramic sheet 1, forming a uniform bonding interface. During installation, maintenance personnel first clean the bolt end face, apply conductive adhesive, and press the piezoelectric ceramic sheet 1 into place. After the adhesive layer cures, permanent adhesion is achieved. This adhesion method avoids damage to the bolt's anti-corrosion layer, ensuring tight contact between the piezoelectric ceramic sheet 1 and the bolt end face, providing a stable foundation for acoustic-electric conversion.

[0025] The magnetic probe 2 covers the piezoelectric ceramic sheet 1 and is quickly fixed by magnetic adsorption. The magnetic probe 2 integrates a ring magnet 21, which generates a strong magnetic field that attracts the probe to the metal substrate on the bolt end face. The bottom of the magnetic probe 2's outer shell is designed with a flat structure, fitting snugly against the surface of the piezoelectric ceramic sheet 1. The adsorption force of the ring magnet 21 keeps the magnetic probe 2 in a stable position. The spring pin 22 and the ring metal sheet 23 respectively contact the positive and negative poles of the piezoelectric ceramic sheet 1, forming an electrical connection path. The magnetic adsorption mechanism allows maintenance personnel to quickly install and remove the probe, adapting to the operational needs of wind turbine units in confined spaces.

[0026] The portable axial force meter 3 is externally connected to the magnetic probe 2 via a shielded cable. One end of the cable connects to the signal interface of the magnetic probe 2, and the other end is inserted into the input port of the portable axial force meter 3. The portable axial force meter 3 integrates an ultrasonic excitation module and a timer. The ultrasonic excitation module generates a high-frequency electrical signal, which is transmitted to the magnetic probe 2 via the cable. The electrical signal is then conducted to the piezoelectric ceramic plate 1 via the spring pin 22 and the annular metal plate 23. The portable axial force meter 3 has an operating interface and a data display screen on its casing, facilitating on-site reading of measurement results. The external connection method allows for flexible deployment of the equipment, reducing the burden of tower climbing operations.

[0027] The positional relationship and connection sequence of the components constitute a complete detection chain: the piezoelectric ceramic sheet 1 serves as the sensing base, fixed to the bolts; the magnetic probe 2 acts as an intermediate connector covering it; and the portable axial force meter 3 serves as the processing unit, externally connected to complete signal interaction. This structural layout ensures the continuity of the detection process, forming a seamless connection from sensor attachment to signal processing, thus improving the overall reliability of the device.

[0028] Specifically, in the magnetic wind power bolt piezoelectric sensing device of this utility model, the central circular area of ​​the piezoelectric ceramic sheet 1 serves as the positive electrode, and the edge annular area is connected to the back surface as the negative electrode.

[0029] The electrode structure of the piezoelectric ceramic sheet 1 adopts a partitioned design, with the central circular area serving as the positive electrode and the peripheral annular area connected to the back surface via an internal conductive path to form the negative electrode. This electrode layout is achieved through the plating process of the piezoelectric ceramic sheet 1. The diameter of the central circular positive electrode area is smaller than that of the peripheral annular area, and the width of the peripheral annular area is uniformly distributed. The back electrode covers the entire back surface, forming a continuous conductive layer. The partitioned electrode design concentrates the positive electrode at the center point, while the negative electrode surrounds the periphery, providing a clear path for electrical signal transmission.

[0030] The positive and negative electrodes of the piezoelectric ceramic sheet 1 are electrically isolated through metallization. An insulating gap exists between the central circular positive electrode region and the peripheral annular negative electrode region to prevent short circuits. The connection between the peripheral annular region and the back electrode is achieved through the metal plating on the sidewall of the piezoelectric ceramic sheet 1 or an internal conductive path, ensuring the integrity of the negative electrode circuit. This connection structure is beneficial for optimizing the excitation efficiency of ultrasonic signals during detection, with the positive electrode serving as the signal input point and the negative electrode as the circuit.

[0031] The electrode layout corresponds to the components of the magnetic probe 2. The spring-loaded pin 22 contacts the central circular positive electrode area of ​​the piezoelectric ceramic sheet 1, while the annular metal sheet 23 contacts the edge annular negative electrode area. This point-to-surface contact combination improves the reliability of the electrical connection. The central positive electrode focuses ultrasonic energy, while the edge negative electrode provides a stable circuit, reducing signal interference. The overall electrode structure supports the acoustic-to-electric conversion function of the piezoelectric ceramic sheet 1, laying the foundation for the detection accuracy of the device.

[0032] Specifically, the magnetic suction type piezoelectric sensing device for wind turbine bolts of this utility model includes a ring magnet 21, a spring pin 22, and a ring metal sheet 23. The spring pin 22 contacts the positive electrode of the piezoelectric ceramic sheet 1, and the ring metal sheet 23 contacts the negative electrode of the piezoelectric ceramic sheet 1.

[0033] The magnetic probe 2, serving as a connecting unit, consists of three core components: a ring magnet 21, a spring pin 22, and a ring metal plate 23. These components are mechanically integrated into the housing of the magnetic probe 2, forming a complete electrical connection and magnetic adsorption structure. The housing of the magnetic probe 2 is made of engineering plastic, and its internal space is designed with a multi-layered layout to support the fixation and cooperation of each component.

[0034] A ring magnet 21 is positioned in the middle layer of the magnetic probe 2, generating a magnetic field that attracts the metal substrate at the bolt end. The ring magnet 21 has a ring-shaped structure with a central cavity to allow the spring pin 22 to pass through. The magnetic force of the ring magnet 21 is perpendicular to the plane of the piezoelectric ceramic sheet 1, providing a stable holding force and enabling the magnetic probe 2 to be quickly fixed in the detection position.

[0035] The spring-loaded pin 22 is vertically mounted within the central cavity of the annular magnet 21 and can elastically extend and retract. The head of the spring-loaded pin 22 has a hemispherical design, and the tail is connected to a wire. An internal spring mechanism provides continuous pressure. When the magnetic probe 2 is attracted to the surface of the piezoelectric ceramic sheet 1, the spring-loaded pin 22 automatically compresses or extends to compensate for installation misalignment and maintain reliable point contact with the positive electrode of the piezoelectric ceramic sheet 1.

[0036] The annular metal sheet 23 is located at the bottom of the magnetic probe 2, directly facing the negative electrode area of ​​the piezoelectric ceramic sheet 1. The annular metal sheet 23 is a ring-shaped conductive sheet, with its outer edge flush with the bottom of the housing of the magnetic probe 2, and its inner edge surrounding the mounting position of the spring pin 22. The annular metal sheet 23 is connected to the circuit terminal of the portable axial force meter 3 through a wire, forming a negative electrode path.

[0037] The spring-loaded pin 22 and the annular metal plate 23 are arranged concentrically, with the spring-loaded pin 22 at the center and the annular metal plate 23 surrounding it. This arrangement corresponds to the electrode distribution of the piezoelectric ceramic sheet 1, with the spring-loaded pin 22 making point contact with the central region of the positive electrode and the annular metal plate 23 making surface contact with the edge region of the negative electrode, thus realizing the input and return of current.

[0038] Electrical connections between components are achieved through internal wiring. The wires of the spring pin 22 are connected to the signal output terminal of the portable axial force meter 3, and the wires of the annular metal plate 23 are connected to the signal return terminal. Magnetic adsorption and electrical contact occur simultaneously. The adsorption force of the annular magnet 21 keeps the annular metal plate 23 tightly attached to the surface of the piezoelectric ceramic plate 1, and the spring pin 22 maintains stable contact under pressure, reducing contact resistance.

[0039] In the overall structure, the magnetic probe 2 is quickly installed and removed via a ring magnet 21, while the spring-loaded pin 22 and the ring metal plate 23 ensure the stability and adaptability of the electrical connection. This design solves the problem of bulkiness in existing probes and improves detection efficiency and accuracy.

[0040] Specifically, in the magnetic wind turbine bolt piezoelectric sensing device of this utility model, the piezoelectric ceramic sheet 1 is fixed to the end face of the bolt being detected by an adhesive layer, and the adhesive layer covers the back of the piezoelectric ceramic sheet 1, so that the piezoelectric ceramic sheet 1 and the bolt end face are connected; the positive and negative electrodes of the piezoelectric ceramic sheet 1 are respectively insulated and isolated from the bolt end face through the conductive area on the adhesive layer.

[0041] The piezoelectric ceramic sheet 1 is fixedly connected to the bolt end face through an adhesive layer made of epoxy resin, which covers the entire back surface of the piezoelectric ceramic sheet 1. After the adhesive layer is applied to the back of the piezoelectric ceramic sheet 1, the piezoelectric ceramic sheet 1 is pressed to adhere to the bolt end face. After the adhesive layer cures, a mechanical connection is formed. This fixing method avoids damage to the anti-corrosion layer of the bolt and ensures the long-term stability of the piezoelectric ceramic sheet 1.

[0042] When the adhesive layer covers the back of the piezoelectric ceramic sheet 1, a uniform coating process is used to ensure consistent thickness and form a continuous coating. The contact surface between the adhesive layer and the bolt end face undergoes surface treatment to enhance adhesion. After cleaning the bolt end face, adhesive is applied, and the piezoelectric ceramic sheet 1 is placed in the predetermined position. During the curing process, the adhesive layer fills the tiny gaps, achieving a seamless connection. This coating method makes the piezoelectric ceramic sheet 1 and the bolt end face an integral structure, supporting the reliability of sound wave transmission.

[0043] The positive and negative electrodes of the piezoelectric ceramic sheet 1 are electrically connected through conductive areas on the adhesive layer, while simultaneously being insulated from the bolt end face. The conductive areas, made of silver paste or conductive adhesive, are positioned at specific locations on the adhesive layer, corresponding to the positive and negative contacts of the piezoelectric ceramic sheet 1. Insulation is achieved through non-conductive materials within the adhesive layer, and an insulating barrier surrounds the conductive areas to prevent short circuits between the positive and negative electrodes and the bolt's metal substrate. This design ensures that electrical signals are transmitted only through a predetermined path, reducing interference.

[0044] The adhesive layer structure supports the electrode layout of the piezoelectric ceramic sheet 1, with the positive and negative electrodes connected to subsequent circuits via wires extending from the conductive areas. An insulation mechanism prevents leakage risks and improves detection accuracy. The overall adhesive bonding method simplifies the installation process and is suitable for the harsh environments of wind turbine generators.

[0045] Specifically, in the magnetic suction type piezoelectric sensing device for wind turbine bolts described in this utility model, the magnetic suction probe 2 includes a multi-layer stacked structure for the annular magnet 21, spring pin 22, and annular metal sheet 23: the annular metal sheet 23 is located at the bottom layer, facing the piezoelectric ceramic sheet 1; the annular magnet 21 is stacked above the annular metal sheet 23; the spring pin 22 is vertically disposed in the central hole of the annular magnet 21 and can elastically extend and retract through the annular magnet 21 to contact the positive electrode of the piezoelectric ceramic sheet 1.

[0046] The magnetic probe 2 adopts a multi-layer stacked structure, which optimizes space utilization and improves component collaboration efficiency. The multi-layer stacked structure achieves a compact layout through the vertical arrangement of components. The annular metal sheet 23, the annular magnet 21, and the spring pin 22 are stacked sequentially to form a stable physical connection. The stacking order is based on functional requirements; the bottom layer components directly contact the piezoelectric ceramic sheet 1, while the upper layer components provide support and drive. The overall structure supports the rapid installation and signal transmission of the magnetic probe 2.

[0047] The annular metal sheet 23 is located at the bottom of the stacked structure, directly facing the negative electrode region of the piezoelectric ceramic sheet 1. The planar arrangement of the annular metal sheet 23 is parallel to the surface of the piezoelectric ceramic sheet 1, ensuring a large-area contact. The annular metal sheet 23 acts as a conductive medium, transmitting the electrical signal from the negative electrode of the piezoelectric ceramic sheet 1 to the portable axial force meter 3, while also providing mechanical support. Its bottom-layer position ensures that the annular metal sheet 23 contacts the piezoelectric ceramic sheet 1 first, reducing the signal transmission path length.

[0048] A ring magnet 21 is stacked on top of a ring metal sheet 23, and the magnetic probe 2 is fixed in position by magnetic adsorption. The ring structure of the ring magnet 21 has a cavity in the center, allowing the spring pin 22 to pass through. This stacking method ensures that the pressure of the ring magnet 21 is evenly transmitted to the ring metal sheet 23, enhancing adsorption stability. The magnetic field generated by the ring magnet 21 acts on the metal substrate at the bolt end face, providing the main holding force and enabling rapid positioning of the magnetic probe 2.

[0049] The spring-loaded pin 22 is vertically positioned within the central hole of the annular magnet 21 and can elastically extend and retract. The axis of the spring-loaded pin 22 is perpendicular to the plane of the piezoelectric ceramic sheet 1, and its head is designed in a hemispherical shape to reduce contact resistance. The elastic extension and retraction mechanism is achieved through an internal spring, allowing the spring-loaded pin 22 to adapt to the unevenness of the piezoelectric ceramic sheet 1 surface. The vertical arrangement ensures that the spring-loaded pin 22 is precisely aligned with the positive electrode center area of ​​the piezoelectric ceramic sheet 1, forming a point contact.

[0050] When the spring-loaded pin 22 passes through the center hole of the annular magnet 21, it maintains insulation from the annular magnet 21 to prevent short circuits. The range of extension and retraction is controlled by the stroke of the spring-loaded pin 22 to compensate for installation deviations. When the magnetic probe 2 is attracted, the spring-loaded pin 22 is compressed and retracts, maintaining a stable contact pressure under the action of spring force. This design ensures the reliability of the electrical connection and reduces signal fluctuations.

[0051] The positional relationship of each component in the multi-layered stacked structure supports functional synergy. The annular metal sheet 23 serves as the basic conductive layer, the annular magnet 21 provides fixing force, and the spring pin 22 achieves precise electrical contact. The stacked structure simplifies the assembly process, improves the overall rigidity and adaptability of the magnetic probe 2, and this layout solves the problem of the bulkiness of existing probes.

[0052] Specifically, in the magnetic wind turbine bolt piezoelectric sensing device of this utility model, the bottom of the outer shell of the magnetic probe 2 is provided with an annular groove, which is used to accommodate and limit the edge of the piezoelectric ceramic sheet 1; the tip of the spring pin 22 protrudes from the bottom of the outer shell and forms point contact with the positive electrode of the piezoelectric ceramic sheet 1; the annular metal sheet 23 is flush with the bottom of the outer shell and forms surface contact with the negative electrode of the piezoelectric ceramic sheet 1.

[0053] The bottom annular groove of the magnetic probe 2 housing is designed as an annular groove structure, surrounding the bottom perimeter of the housing. The groove depth matches the edge thickness of the piezoelectric ceramic sheet 1. The inner diameter of the annular groove is adapted to the outer diameter of the piezoelectric ceramic sheet 1. When the magnetic probe 2 is attracted, the sidewall of the groove surrounds the edge of the piezoelectric ceramic sheet 1, restricting its radial movement and achieving precise positioning. This containment and limiting mechanism prevents the piezoelectric ceramic sheet 1 from shifting during the detection process, ensuring the stability of signal transmission.

[0054] The tip of the spring-loaded pin 22 protrudes from the bottom of the magnetic probe 2 housing, and its protrusion height is controlled by the pre-compression of the spring-loaded pin 22. The tip adopts a hemispherical design, forming a concentrated point contact when it contacts the central region of the positive electrode of the piezoelectric ceramic sheet 1. This point contact reduces the contact area and lowers the contact resistance. Simultaneously, the elastic expansion and contraction of the spring-loaded pin 22 compensates for minor surface irregularities of the piezoelectric ceramic sheet 1, maintaining a constant contact pressure. This design optimizes electrical signal transmission efficiency and reduces energy loss.

[0055] The annular metal plate 23 is flush with the bottom of the magnetic probe 2 housing, and the surface flatness of the metal plate is consistent with the bottom surface of the housing. This flush arrangement ensures that the annular metal plate 23 fully covers the negative electrode edge area of ​​the piezoelectric ceramic plate 1, forming a uniform surface contact. Surface contact increases the conductive area, improves the reliability of current conduction, and reduces the risk of localized overheating. The fixed position of the annular metal plate 23 works in conjunction with the spring-loaded pin 22 to complete the positive and negative electrode circuit connection.

[0056] The limiting function of the annular groove provides a basic guarantee for the contact between the spring pin 22 and the annular metal piece 23. After the groove is positioned, the point contact of the spring pin 22 and the surface contact of the annular metal piece 23 establish an electrical connection in sequence. This sequential layout improves the assembly accuracy of the device, and the structural synergy of each component enhances the overall rigidity.

[0057] This invention addresses the pain points of existing ultrasonic probe technology through structural innovation. Specifically, the solution is based on the collaborative operation of components in a magnetically attached piezoelectric sensing device for wind turbine bolts. The piezoelectric ceramic sheet 1 is directly fixed to the bolt end face using a permanent adhesive layer, eliminating the need for grinding the anti-corrosion layer and preventing secondary damage. The miniaturized design of the piezoelectric ceramic sheet 1 adapts to confined spaces, and the optimized electrode layout improves acoustic-to-electric conversion efficiency. The magnetically attached probe 2 uses a ring magnet 21 to generate an attraction force for quick installation and removal. A spring-loaded pin 22 elastically contacts the positive electrode of the piezoelectric ceramic sheet 1, while the ring metal sheet 23 contacts the negative electrode, forming a stable electrical connection and reducing signal fluctuations. The compact stacked structure of the magnetically attached probe 2 reduces its size and improves deployment flexibility. A portable axial force meter 3 externally processes the signal, integrating an ultrasonic excitation module and a timer. It connects to the magnetically attached probe 2 via a cable to achieve high-precision propagation time measurement. The component positions are as follows: the piezoelectric ceramic sheet 1 serves as the basic sensor, the magnetically attached probe 2 covers and connects it, and the portable axial force meter 3 processes the signal remotely. The overall structure ensures the continuity of the detection process. This device design eliminates the bulkiness of existing probes, and improves detection efficiency and accuracy while reducing maintenance interference through non-destructive installation, magnetic quick connection, and integrated processing.

[0058] Embodiment 1 of this utility model: In the scenario of inspecting wind turbine blade root bolts, maintenance personnel first clean the bolt end face after climbing the tower. Then, they use epoxy resin adhesive to fix the piezoelectric ceramic sheet 1 to the bolt end face, with the adhesive layer evenly covering the back of the piezoelectric ceramic sheet 1, forming a mechanical connection without damaging the anti-corrosion layer. In the electrode layout of the piezoelectric ceramic sheet 1, the central circular area serves as the positive electrode, and the edge annular area, which is connected to the back surface, serves as the negative electrode. The bolt substrate is isolated by insulating material. During inspection, the magnetic probe 2 is attracted to the piezoelectric ceramic sheet 1. The annular magnet 21 generates an attractive force to fix the position, the spring pin 22 elastically contacts the central area of ​​the positive electrode, and the annular metal sheet 23 contacts the edge area of ​​the negative electrode, establishing an electrical path. The portable axial force meter 3 is connected to the magnetic probe 2 via a shielded cable, integrating an ultrasonic excitation module to emit a megahertz frequency signal. A timer records the change in sound wave propagation time, and the data is uploaded to the monitoring system. This process is completed within seconds, adapting to the narrow space at the blade root, avoiding secondary damage, and improving inspection efficiency and accuracy.

[0059] Embodiment 2 of this utility model: In the application of wind turbine tower bolt inspection, the bolts are densely distributed and the inspection frequency is low. This utility model device achieves rapid batch operation through modular design. Piezoelectric ceramic sheets 1 are permanently attached to multiple bolt end faces through an adhesive layer, forming a sensor network; the compact stacked structure of the magnetic probe 2, with annular metal sheets 23 at the bottom and annular magnets 21 stacked on top, and spring-loaded pins 22 vertically passing through the central hole, allows maintenance personnel to sequentially connect and attract the bolts. The extension and retraction stroke of the spring-loaded pins 22 compensates for installation deviations, ensuring point contact stability. The portable axial force meter 3 is lightweight and portable, connected remotely via cable, excites ultrasonic waves and processes axial force attenuation data, reducing tower climbing time. This streamlined inspection mode optimizes resource allocation, reduces maintenance interference, and supports the detachable connection and integrated functions described in the claims.

Claims

1. A magnetically attached piezoelectric sensing device for wind turbine bolts, characterized in that, include: A piezoelectric ceramic sheet (1) is fixed to the end face of the bolt being tested; The magnetic probe (2) is detachably connected to the piezoelectric ceramic sheet (1); A portable axial force meter (3) is connected to the magnetic probe (2) via a cable and integrates an ultrasonic excitation module and a timer; The piezoelectric ceramic sheet (1) is used to complete the acoustic-electric conversion, the magnetic probe (2) is used to ensure quick disassembly and assembly and electrical connection stability, and the portable axial force meter (3) is used to excite ultrasonic waves and measure the change in propagation time.

2. The magnetically attached piezoelectric sensing device for wind turbine bolts as described in claim 1, characterized in that, The piezoelectric ceramic sheet (1) is attached to the end face of the bolt, the magnetic probe (2) covers the piezoelectric ceramic sheet (1) and is fixed by magnetic adsorption, and the portable axial force meter (3) is externally connected to the magnetic probe (2).

3. The magnetically attached piezoelectric sensing device for wind turbine bolts as described in claim 1, characterized in that, The piezoelectric ceramic sheet (1) has a central circular region as the positive electrode and an edge annular region that is connected to the back surface as the negative electrode.

4. The magnetically attached piezoelectric sensing device for wind turbine bolts as described in claim 1, characterized in that, The The magnetic probe (2) includes a ring magnet (21), a spring pin (22) and a ring metal plate (23). The spring pin (22) contacts the positive electrode of the piezoelectric ceramic plate (1), and the ring metal plate (23) contacts the negative electrode of the piezoelectric ceramic plate (1).

5. The magnetically attached piezoelectric sensing device for wind turbine bolts as described in claim 1, characterized in that, The piezoelectric ceramic sheet (1) is fixed to the end face of the bolt being tested by an adhesive layer. The adhesive layer covers the back of the piezoelectric ceramic sheet (1), so that the piezoelectric ceramic sheet (1) and the end face of the bolt are connected. The positive and negative electrodes of the piezoelectric ceramic sheet (1) are respectively insulated and isolated from the end face of the bolt through the conductive area on the adhesive layer.

6. The magnetically attached piezoelectric sensing device for wind turbine bolts as described in claim 4, characterized in that, In the magnetic probe (2), the annular magnet (21), spring pin (22) and annular metal sheet (23) are arranged in a multi-layer stacked structure: the annular metal sheet (23) is located at the bottom layer and faces the piezoelectric ceramic sheet (1); the annular magnet (21) is stacked on top of the annular metal sheet (23); the spring pin (22) is vertically arranged in the center hole of the annular magnet (21) and can elastically extend and retract through the annular magnet (21) to contact the positive pole of the piezoelectric ceramic sheet (1).

7. The magnetically attached piezoelectric sensing device for wind turbine bolts as described in claim 6, characterized in that, The bottom of the housing of the magnetic probe (2) is provided with an annular groove, which is used to accommodate and limit the edge of the piezoelectric ceramic sheet (1); the tip of the spring pin (22) protrudes from the bottom of the housing and forms a point contact with the positive electrode of the piezoelectric ceramic sheet (1); the annular metal sheet (23) is flush with the bottom of the housing and forms a surface contact with the negative electrode of the piezoelectric ceramic sheet (1).

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