A self-centering detection device and method for in-situ re-measurement of ultrasonic pre-tightening force of a bolt

Abstract

The application provides a self-centering detection device and method for ultrasonic pre-tightening force in-situ re-measurement of a bolt, which comprises a reference clamping base, a front-end self-centering detection execution mechanism, a middle-section force transmission and loading mechanism and a rear-end operation and processing mechanism which are installed on the reference clamping base; a coarse positioning structure is slidably installed on the reference clamping base; the front-end self-centering detection execution mechanism is used for realizing the introduction of an exposed end of a target component, self-centering alignment, temperature collection, local coupling and ultrasonic re-measurement; the middle-section force transmission and loading mechanism is used for realizing the pre-pressing application, constant pressure loading and stroke limitation of the front-end measurement structure; and the rear-end operation and processing mechanism is used for completing ultrasonic signal collection, temperature correction, result display and data storage. According to the scheme, under the condition that the target bolt is not disassembled, the ultrasonic measurement end can realize in-situ re-measurement on the accessible axial end face of the target component through the reference clamping, self-centering guidance, constant pressure loading, stable coupling and temperature compensation and the like.

Description

Technical Field

[0001] This invention relates to the field of energy equipment connector condition detection and metal monitoring technology, specifically to a self-centering detection device and method for in-situ retesting of bolt ultrasonic preload. Background Technology

[0002] In energy equipment, many critical connection structures utilize flange high-strength bolts or studs. The preload condition of these bolts directly affects connection sealing, structural stability, and long-term operational safety. In wind power, high-strength bolts are widely used in tower connection flanges, yaw connection flanges, and large component connection structures. In thermal power, turbine cylinder connections, high-temperature and high-pressure flange connections, and some critical pressure-bearing equipment also involve numerous high-strength bolts or stud pairs. During long-term service, these connections are affected by alternating loads, vibration and shock, start-up and shutdown conditions, temperature fluctuations, and environmental factors, which may lead to preload attenuation, loosening, or uneven distribution. Therefore, regular retesting and condition assessment of the target bolts are necessary.

[0003] Among existing methods for detecting bolt preload, ultrasonic testing has become an important means of assessing the condition of high-strength flange bolts due to its advantages such as non-destructive connection, axial measurement capability, and suitability for in-situ retesting. However, in practical field applications, ultrasonic retesting of high-strength flange bolts still faces many difficulties. First, the target bolts are usually already installed and in service, and frequent disassembly is not advisable. The space constraints imposed by the flange structure, the shape of adjacent bolts and nuts, and the layout of surrounding equipment make it difficult to quickly and stably align the probe with the target bolt's axial end face. Second, existing retesting methods often rely on manual measurement with the probe held close to the target end face. Poor coaxiality between the probe and the bolt axis makes it difficult to maintain consistent probe contact pressure and coupling state, leading to fluctuations in results when repeated measurements are performed by different personnel at different times. Third, significant variations in field temperature conditions, especially for wind and thermal power equipment, can cause changes in the sound velocity and propagation time of the bolt material due to differences in shutdown windows, ambient temperature, or residual temperature. Without synchronized temperature acquisition and unified compensation, reliable comparison of subsequent retest results is difficult.

[0004] Furthermore, in batch retesting scenarios, there is a problem that subsequent retests of the same target bolt often fail to return to the same measurement position, measurement posture, and coupling conditions. For double-ended stud connections, although the exposed end face of the stud can usually be used as the measurement end face, manual measurement is still prone to issues such as probe eccentricity, unstable contact pressure, and inconsistent local coupling. For connection types where the bolt head end face is accessible, the same problems of insufficient positioning repeatability and retest consistency also exist. These issues reduce the comparability of retest data between different batches of the same target bolt, which is detrimental to judging the trend of preload changes and forming supervisory conclusions.

[0005] Therefore, there is an urgent need for a dedicated testing device and method for ultrasonic retesting of high-strength flange bolts in service, which can achieve rapid positioning, self-centering, constant pressure coupling, temperature compensation, and retesting reset of the target bolt without disassembling it, thereby improving the consistency, accuracy, and on-site efficiency of in-situ ultrasonic preload retesting of high-strength flange bolts. Summary of the Invention

[0006] To address the problems existing in the background art, the present invention proposes a self-centering detection device for in-situ retesting of ultrasonic preload of bolts, comprising a reference clamping base, on which a front-end self-centering detection execution mechanism, a middle-section force transmission and loading mechanism, and a rear-end operation and processing mechanism are sequentially connected along the axial direction; a coarse positioning structure is also slidably installed on the reference clamping base. The front-end self-centering detection actuator is used to realize the introduction, self-centering, temperature acquisition, local coupling, and ultrasonic retesting of the exposed end of the target component; the middle-section force transmission and loading mechanism is used to realize the pre-pressure application, constant pressure loading, and stroke limitation of the front-end measurement structure; the rear-end operation and processing mechanism is used to complete ultrasonic signal acquisition, temperature correction, result display, and data storage.

[0007] Preferably, the front-end self-centering detection actuator includes an open-type self-centering guide sleeve, an ultrasonic transducer assembly, and a front-end probe mounting base; The rear end of the ultrasonic transducer assembly is detachably connected to the front probe mounting base via a quick-change interface, and its front end is located inside the open-type self-centering guide sleeve. The open-type self-centering guide sleeve has a semi-enclosed structure with an open front end. Its front end is connected to an arc-shaped guide surface, and the front end of the arc-shaped guide surface is connected to an inlet cone surface. The inner diameter of the inlet cone surface gradually decreases from the arc-shaped guide surface towards the front end. The ultrasonic transducer assembly is coaxially arranged with the open-type self-centering guide sleeve. The ultrasonic transducer is connected to one end of a cable via a signal and power transmission interface, and the other end of the cable is connected to the back-end operation and processing mechanism.

[0008] Preferably, the ultrasonic transducer assembly includes a probe housing, a piezoelectric crystal is disposed inside the probe housing, a matching layer is disposed at the front end of the piezoelectric crystal, and a temperature sensor array and a signal conversion cavity are disposed at the rear end of the piezoelectric crystal; The front end of the matching layer is covered with a wear-resistant protective layer, and the outer end face of the front end of the wear-resistant protective layer is the working end face of the probe; the wear-resistant protective layer is provided with a coupling liquid spray outlet; The probe housing has a coupling fluid storage chamber located at the rear end near the temperature sensor array and signal conversion cavity. The coupling fluid storage chamber is connected to the coupling fluid spray outlet via a micro-coupling fluid delivery conduit. The temperature sensor array and signal conversion cavity are connected to the back-end operation and processing mechanism via signal lead-out lines; The probe housing has a temperature acquisition contact on the outer front side, which is connected to the temperature sensor array and the signal conversion cavity.

[0009] Preferably, the mid-section force transmission and loading mechanism includes a preloaded loading seat, a guide slide, and a stroke limiting seat connected in sequence along the direction away from the front-end self-centering detection and execution mechanism. The preloaded loading seat and the guide slide are connected by an upper guide rod and a lower guide rod arranged in parallel. The rear-end operation and processing mechanism is provided with an auxiliary guide rod and a force transmission rod for driving the guide slide. The guide slide is slidably mounted on the auxiliary guide rod. The end of the guide slide away from the preload seat is connected to the force transmission rod. The axial direction of the auxiliary guide rod is consistent with the driving direction of the force transmission rod. The auxiliary guide rod is parallel to the upper guide rod and the lower guide rod. The auxiliary guide rod is provided with a travel limit seat that can slide and lock along the auxiliary guide rod. The travel limit seat is located between the guide slide and the rear operation and processing mechanism. A limit plate is fixed to the end of the auxiliary guide rod away from the travel limit seat.

[0010] Preferably, the preload base is connected to the upper end of the front support arm via a front loading connector, and the lower end of the front support arm is connected to the reference clamping base via a height-adjustable support foot.

[0011] Preferably, the rear-end operation and processing mechanism is fixed with a slide side limiting block, which is located on both sides of the guide slide.

[0012] Preferably, the back-end operation and processing mechanism is a main control processing host, which is connected to the auxiliary guide rod and the force transmission rod through a host connector and a front-end connector sleeve; the main control processing host includes a main control processing host shell and a rear-end connection port, and the main control processing host shell is provided with function buttons, a display screen and a lifting handle.

[0013] Preferably, the back-end operation and processing mechanism includes a power supply unit, a function control unit, a main control processing unit, an ultrasonic signal acquisition and conditioning unit, a data storage and communication unit, and a result display and interaction unit. The power supply unit is electrically connected to the cable, force transmission rod, function control unit, main control processing unit, ultrasonic signal acquisition and conditioning unit, data storage and communication unit, result display and interaction unit, function buttons, and display screen, respectively. The function control unit is connected to the function buttons and the main control processing unit, respectively. The main control processing unit is connected to the force transmission rod, ultrasonic signal acquisition and conditioning unit, data storage and communication unit, result display and interaction unit, function buttons, and display screen, respectively. The ultrasonic signal acquisition and conditioning unit is connected to the signal lead wire. The data storage and communication unit is connected to the back-end connection port.

[0014] Preferably, the coarse positioning structure includes an electromagnet, a V-shaped positioning support, and a lockable anti-slip wheel. The electromagnet is movably mounted on the lockable anti-slip wheel via an axial position adjustment mechanism. The V-shaped positioning support is movably mounted on the lockable anti-slip wheel via a height adjustment mechanism. The lockable anti-slip wheel is slidably mounted on the reference clamping base. The electromagnet is electrically connected via a wire to an electromagnet control switch for controlling its start and stop.

[0015] A self-centering detection method for in-situ retesting of ultrasonic preload of bolts includes the following steps: S1. Determine the target component based on the flange connection location to be tested. The target component is a target stud or target bolt. Move the self-centering detection device to the vicinity of the exposed end of the target component. S2. Place the front end of the reference clamping base against the outer end face of the flange to be tested, adjust the relative distance between the coarse positioning structure and the flange to be tested by the lockable anti-slip wheel, and adjust the support height and installation posture of the front end of the device by the height adjustment support foot. S3. Adjust the extension position of the electromagnet through the axial position adjustment mechanism to make the electromagnet fit against the outer end face of the flange to be tested; activate the electromagnet control switch to make the coarse positioning structure adsorb and fix on the surface of the flange to be tested. S4. Adjust the V-shaped positioning support through the height adjustment mechanism to raise the V-shaped positioning support to the outer contour of the exposed end of the target component, and place the exposed end of the target component in the V-shaped positioning surface of the V-shaped positioning support to form a limiting fit and achieve coarse positioning of the target component. S5. After completing the reference clamping and coarse positioning, push the front self-centering detection execution area close to the exposed end of the target component. The exposed end of the target component first enters the open self-centering guide sleeve. Under the combined action of the guide cone surface and the arc guide surface, the outer contour of the target component and the open self-centering guide sleeve form a guiding fit, so that the measurement axis of the ultrasonic transducer assembly tends to coincide with the axis of the target component. S6. After completing the self-centering alignment, set the contact pressure between the ultrasonic transducer assembly and the exposed end face of the target component using the pre-pressure adjustment knob; the mid-section force transmission and loading zone guides the front-end measuring structure to move smoothly along the axial direction of the target component through the upper guide rod, auxiliary guide rod, lower guide rod, guide slide, and force transmission rod; the stroke limit adjustment knob and stroke limit seat limit the axial movement stroke of the front-end measuring end. S7. During the measurement process, the coupling medium in the coupling fluid storage chamber is delivered to the vicinity of the probe working end face through the micro-coupling fluid delivery conduit and the coupling fluid spray outlet, so that a thin coupling interface is formed between the probe working end face and the exposed end face of the target component. Under the control of the back-end main control processing unit, the piezoelectric crystal emits ultrasonic signals and receives the echo signals propagating along the axis of the target component. Temperature acquisition contacts, temperature sensor array, and signal conversion cavity synchronously acquire temperature parameters of the area adjacent to the target component. The back-end operation and processing area receives, amplifies, filters, and extracts time parameters from the echo signals through the ultrasonic signal acquisition and conditioning unit to obtain the retest parameters of the target component's pre-tightening state. The main control processing unit corrects the retest results based on the temperature parameters and outputs the measurement status, temperature parameters, pre-tightening state retest results, and target component information through the display screen and result display and interaction unit. The data storage and communication unit is used to save the target component number, temperature parameters, retest results, and historical records. S8. After completing the retest of the current target component, turn off the electromagnet control switch, release the electromagnetic adsorption, lower the V-shaped positioning support, and move the device to the position of the next target component column for retesting.

[0016] The beneficial effects of this invention are as follows: This invention enables in-situ ultrasonic retesting of high-strength bolts in the pre-tightened state of energy equipment flanges without disassembling the target studs or bolts. This invention establishes a stable installation benchmark through a coarse positioning structure, achieving coarse positioning and anti-deviation limiting of the target component. An open-type self-centering guide sleeve enables automatic alignment of the ultrasonic measurement axis with the target component axis. A mid-section force transmission and loading mechanism achieves controlled pre-pressure bonding, constant pressure loading, and loading stroke limitation. Finally, a rear-end operation and processing mechanism completes ultrasonic signal acquisition, temperature correction, result display, and data storage.

[0017] This invention effectively solves the problems existing in the retesting process using handheld ultrasonic probes, such as reliance on experience for target bolt positioning, poor probe coaxiality, inconsistent contact pressure, unstable coupling state, difficulty in correcting for temperature effects, and insufficient comparability of retesting results for the same bolt. By integrating positioning, alignment, loading, coupling, temperature correction, and data output into a single device, the stability, repeatability, and reliability of in-situ retesting of high-strength flange bolts can be improved, reducing the reliance on operator experience for on-site retesting.

[0018] This invention is particularly applicable to the on-site supervision and inspection of high-strength bolts or double-ended stud connections in the flange connections of wind turbine towers, yaw bearings, thermal power plants, high-temperature and high-pressure flanges, and other energy equipment flanges. It can provide a more stable basis for retesting to track bolt preload status, judge loosening trends, and make maintenance decisions. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the back-end operation and processing mechanism of the present invention; Figure 3 This is a schematic diagram of the ultrasonic transducer assembly structure of the present invention; Figure 4 This is a schematic diagram of the working state of the present invention.

[0020] Labels in the diagram: 1. Inlet cone surface; 2. Arc guide surface; 3. Open self-centering guide sleeve; 4. Ultrasonic transducer assembly; 5. Front probe mounting base; 6. Quick-change interface; 7. Signal and power transmission interface; 8. Cable; 9. Preload base; 10. Preload adjustment knob; 11. Upper guide rod; 12. Guide slide; 13. Auxiliary guide rod; 14. Force transmission rod; 15. Travel limit adjustment knob; 16. Main unit connection base; 17. Handle; 18. Function button; 19. Rear connection port; 20. Main control unit housing; 21. Display screen; 22. Main unit front connection sleeve; 23. Travel limit seat; 24. Lateral limit block; 25. Lower guide rod; 26. Height adjustment support foot; 27. Reference clamping base; 28. Front support arm; 29. ​​Front end 30. Loading connector; 31. Axial adjustment knob; 32. Height adjustment knob; 33. Lockable anti-slip wheel; 34. Electromagnet; 35. Control switch; 36. V-shaped positioning support; 37. Flange; 38. Temperature acquisition contact; 39. Power supply unit; 40. Function control unit; 41. Main control processing unit; 42. Ultrasonic signal acquisition and conditioning unit; 43. Data storage and communication unit; 44. Result display and interaction unit; 45. Probe working end face; 46. Wear-resistant protective layer; 47. Backing layer; 48. Matching layer; 49. Probe housing; 50. Piezoelectric crystal; 51. Temperature sensor array and signal conversion cavity; 52. Signal lead wire; 53. Cable protection sleeve; 54. Coupling fluid storage cavity; 55. Micro-coupling fluid delivery conduit; 56. Coupling fluid spray outlet. Detailed Implementation

[0021] To make the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the given embodiments are merely one implementation method and do not represent all embodiments.

[0022] Combination Figures 1-4 The present invention provides a self-centering detection device for in-situ retesting of ultrasonic preload of bolts, including a reference clamping base 27, on which a front-end self-centering detection execution mechanism, a middle-section force transmission and loading mechanism and a rear-end operation and processing mechanism are sequentially connected along the axial direction; a coarse positioning structure is also slidably installed on the reference clamping base 27. The front-end self-centering detection actuator is used to realize the introduction, self-centering, temperature acquisition, local coupling, and ultrasonic retesting of the exposed end of the target component; the middle-section force transmission and loading mechanism is used to realize the pre-pressure application, constant pressure loading, and stroke limitation of the front-end measurement structure; the rear-end operation and processing mechanism is used to complete ultrasonic signal acquisition, temperature correction, result display, and data storage.

[0023] Specifically, the front-end self-centering detection actuator includes an open-type self-centering guide sleeve 3, an ultrasonic transducer assembly 4, and a front-end probe mounting base 5; The rear end of the ultrasonic transducer assembly 4 is detachably connected to the front probe mounting base 5 via a quick-change interface 6, and its front end is located inside the open self-centering guide sleeve 3. The open-type self-centering guide sleeve 3 has a semi-enclosed structure with an open front end. Its front end is connected to an arc guide surface 2. The front end of the arc guide surface 2 is connected to an inlet cone surface 1. The inner diameter of the inlet cone surface 1 gradually decreases from the arc guide surface 2 towards the front end. The ultrasonic transducer assembly 4 is coaxially arranged with the open-type self-centering guide sleeve 3. The ultrasonic transducer 4 is connected to one end of a cable 8 via a signal and power transmission interface 7, and the other end of the cable 8 is connected to the back-end operation and processing mechanism.

[0024] During testing, the open-type self-centering guide sleeve 3 approaches the exposed end of the target component (bolt or stud). The exposed end of the target component gradually enters the semi-enclosed structure of the open-type self-centering guide sleeve 3. The open-type self-centering guide sleeve 3 guides, limits, and aligns the target component, ensuring that the measuring axis of the ultrasonic transducer assembly 4 coincides with the axis of the target component. The open-type self-centering guide sleeve 3 achieves the guidance and self-centering of the target component without disassembling it.

[0025] The ultrasonic transducer 4 is used to axially emit ultrasonic signals to the target stud and receive echo signals to obtain the retest parameters of the target stud preload state; the front probe mounting base 5 is used to install, support and position the ultrasonic transducer 4; the quick-change interface 6 is used to realize the quick assembly and disassembly of the ultrasonic transducer 4; the signal and power transmission interface 7 and the cable 8 are used to realize the signal and power connection between the self-centering detection actuator and the back-end operation and processing mechanism.

[0026] More specifically, the front probe mounting base 5 has a mounting hole on its front side, and the rear end of the ultrasonic transducer assembly 4 is inserted into the mounting hole. The quick-change interface 6 includes symmetrically arranged clamping blocks, which are located in the mounting hole and connected to the mounting hole via springs. The springs extend in the same direction as the radial direction of the mounting hole. The opposite sides of the clamping blocks are arc-shaped, and the outer wall of the rear end of the ultrasonic transducer assembly 4 has a groove that matches the arc-shaped surface of the clamping blocks. When installing the ultrasonic transducer assembly 4, the rear end of the ultrasonic transducer assembly 4 is inserted into the mounting hole, and the ultrasonic transducer assembly 4 spreads the two clamping blocks apart, causing the two clamping blocks to move away from each other. At this time, the spring is compressed. When the ultrasonic transducer assembly 4 moves to the position of the groove corresponding to the clamping block, the clamping block enters the groove, completing the installation of the ultrasonic transducer assembly 4. At this time, the spring is still in a compressed state, and the clamping blocks hold the ultrasonic transducer assembly 4 under the action of the spring. Under the limiting action of the groove, the axial movement of the ultrasonic transducer assembly 4 is restricted, and the rear end face of the ultrasonic transducer assembly 4 abuts against the inner wall of the mounting hole. After the ultrasonic transducer assembly 4 is installed, it cannot move backward due to the limiting effect of the clamping block and the inner wall of the mounting hole. Furthermore, without external force applied, the ultrasonic transducer assembly 4 cannot move forward. To disassemble the ultrasonic transducer assembly 4, simply apply a certain forward pulling force to it to open the clamping block and pull it out of the mounting hole.

[0027] The structure of the quick-change interface 6 is not limited to the above-described structure; it only needs to be able to facilitate the easy assembly and disassembly of the ultrasonic transducer component 4, and will not be elaborated here.

[0028] Specifically, the ultrasonic transducer assembly 4 includes a probe housing 48, which is used to house and protect the components located inside it. A piezoelectric crystal 49 is provided inside the probe housing 48. A matching layer 47 is provided at the front end of the piezoelectric crystal 49, and a temperature sensor array and a signal conversion cavity 50 are provided at the rear end of the piezoelectric crystal 49. The front end of the matching layer 47 is covered with a wear-resistant protective layer 45. The outer end face of the front end of the wear-resistant protective layer 45 is the working end face 44 of the probe. The working end face 44 of the probe and the exposed end face of the target component form a measurement interface. The wear-resistant protective layer 45 is provided with a coupling liquid spray outlet 55. The wear-resistant protective layer 45, the matching layer 47, the piezoelectric crystal 49, and the backing layer 46 together constitute the ultrasonic transducer structure, which is used to realize ultrasonic signal transmission, reception, and acoustic matching.

[0029] A coupling fluid storage chamber 53 is provided at the rear end of the probe housing 48 near the temperature sensor array and signal conversion cavity 50. The coupling fluid storage chamber 53 is connected to the coupling fluid outlet 55 via a micro-coupling fluid delivery conduit 54. The coupling fluid storage chamber 53 stores coupling fluid. During detection, the coupling fluid is delivered to the coupling fluid outlet 55 via the micro-coupling fluid delivery conduit 54, and then the coupling fluid outlet 55 delivers the coupling medium to the area adjacent to the probe working end face 44, so that a thin coupling interface is formed between the probe working end face 44 and the target stud end face. The coupling fluid outlet 55 is preferably located on the outer periphery or laterally adjacent to the probe working end face 44 to reduce the impact on the central acoustic beam channel of the ultrasonic transducer 4. The temperature sensor array and signal conversion cavity 50 are connected to the back-end operation and processing mechanism through the signal lead-out line 51. The temperature sensor array and signal conversion cavity 50 are used to collect temperature information and convert or pre-condition the front-end signal. The signal lead-out line 51 is used to realize signal output. The outer wall of the signal lead-out line 51 is provided with a cable protection sleeve 52, which protects the line. A temperature acquisition contact 37 is provided on the outer front end of the probe housing 48. The temperature acquisition contact 37 is connected to the temperature sensor array and signal conversion cavity 50. The temperature acquisition contact 37 is used to acquire the temperature of the exposed end of the target stud, nut, or adjacent metal area, providing parameters for temperature correction. The temperature sensor array and signal conversion cavity 50 contain a temperature sensor array and a signal processor. The temperature acquisition contact 37 is connected to the temperature sensor array, serving as the detection end of the temperature sensor. The signal processor converts and performs preliminary processing on the temperature signal and ultrasonic signal. The temperature sensor array is connected to the signal processor, and the signal processor is connected to the signal lead 51.

[0030] Specifically, the mid-section force transmission and loading mechanism includes a preload seat 9, a guide slide 12 and a stroke limit seat 23 connected in sequence along the direction away from the front-end self-centering detection and execution mechanism. The preload seat 9 and the guide slide 12 are connected by an upper guide rod 11 and a lower guide rod 25 arranged in parallel. The rear-end operation and processing mechanism is provided with an auxiliary guide rod 13 and a force transmission rod 14 for driving the guide slide 12 to slide. The guide slide 12 is slidably mounted on the auxiliary guide rod 13. One end of the guide slide 12 away from the preload seat 9 is connected to the force transmission rod 14. The axial direction of the auxiliary guide rod 13 is consistent with the driving direction of the force transmission rod 14. The auxiliary guide rod 13 is parallel to the upper guide rod 11 and the lower guide rod 25. The auxiliary guide rod 13 is provided with a travel limit seat 23 that can slide and lock along the auxiliary guide rod 13. The travel limit seat 23 is located between the guide slide 12 and the rear operation and processing mechanism. A limit plate is fixed to one end of the auxiliary guide rod 13 away from the travel limit seat 23.

[0031] The preload seat 9 supports the front-end self-centering detection actuator and transmits the loading force; the preload adjustment knob 10 adjusts the contact pressure between the ultrasonic transducer 4 and the exposed end face of the target component; the auxiliary guide rod 13 forms a linear guide, allowing the front-end self-centering detection actuator to move stably along the axial direction of the target component; the guide slide 12 slides with the guide rod and supports the preload seat 9 and related front-end structures; the force transmission rod 14 transmits the axial thrust to the preload seat 9; the stroke limit adjustment knob 15 and the stroke limit seat 23 limit the axial movement stroke of the front-end self-centering detection actuator to prevent overpressure on the ultrasonic transducer 4 probe; the mid-section force transmission and loading mechanism ensures that, after self-centering alignment, the ultrasonic transducer 4 adheres to the exposed end face of the target stud with controlled pressure and a stable posture, thereby improving contact consistency and data stability during the retesting process. Specifically, the preload base 9 is connected to the upper end of the front support arm 28 via the front loading connector 29, and the lower end of the front support arm 28 is connected to the reference clamping base 27 via the height adjustment support foot 26.

[0032] Specifically, a slide side limiting block 24 is fixed on the rear operation and processing mechanism, and the slide side limiting block 24 is located on both sides of the guide slide 12. The slide side limiting block 24 is used to limit the lateral displacement of the guide slide 12.

[0033] More specifically, the force transmission rod 14 can be hydraulically driven to provide axial thrust.

[0034] Specifically, the back-end operation and processing mechanism is a main control processing host. The main control processing host is connected to the auxiliary guide rod 13 and the force transmission rod 14 through the host connector 16 and the host front end connector 22. The main control processing host includes a main control processing host housing 20 and a back end connection port 19. The main control processing host housing 20 is provided with function buttons 18, a display screen 21 and a lifting handle 17.

[0035] The main unit connector 16 and the main unit front-end connector 22 are used to realize the structural connection between the mid-section force transmission and loading mechanism and the rear-end operation and processing mechanism; the lifting handle 17 facilitates the operator to hold and move the detection device; the function button 18 is used to control the device, such as realizing the start and stop of the detection device, measurement triggering, and parameter setting. The rear-end connector is used to connect the detection device to an external power supply, data transmission line, and maintenance structure; the display screen 21 is used to display the measurement status, temperature parameters, retest results, and target component information.

[0036] Specifically, the back-end operation and processing mechanism includes a power supply unit 38, a function control unit 39, a main control processing unit 40, an ultrasonic signal acquisition and conditioning unit 41, a data storage and communication unit 42, and a result display and interaction unit 43; the main control processing unit housing is used to house the power supply unit 38, the function control unit 39, the main control processing unit 40, the ultrasonic signal acquisition and conditioning unit 41, the data storage and communication unit 42, and the result display and interaction unit 43.

[0037] The power supply unit 38 is electrically connected to the cable 8, the force transmission rod 14, the function control unit 39, the main control processing unit 40, the ultrasonic signal acquisition and conditioning unit 41, the data storage and communication unit 42, the result display and interaction unit 43, the function button 18, and the display screen 21, respectively, to supply power to the aforementioned components and function units connected to it; the function control unit 39 is connected to the function button 18 and the main control processing unit 40, respectively; the main control processing unit 40 is connected to the force transmission rod 14, the ultrasonic signal acquisition and conditioning unit 41, the data storage and communication unit 42, the result display and interaction unit 43, the function button 18, and the display screen 21, respectively; the ultrasonic signal acquisition and conditioning unit 41 is connected to the signal lead-out line 51; the data storage and communication unit 42 is connected to the rear connection port; The function control unit 39 is used to receive operation commands from the function key 18 and transmit the commands to the main control processing unit 40. The main control processing unit 40 controls the corresponding components or function units to work according to the received commands. The main control processing unit 40 is used for data reception and processing, such as receiving temperature information collected by the temperature sensor array, ultrasonic signals from the ultrasonic signal acquisition unit, and loading force provided by the force transmission rod 14, and processing each data information to obtain the detection results. The ultrasonic signal acquisition unit receives the ultrasonic echo signal emitted by the ultrasonic transducer component 4 through the signal lead-out line 51, and amplifies, filters, and extracts time parameters from the ultrasonic echo signal to obtain the retest parameters of the target component's pre-tightening state. The data storage and communication unit 42 is used to save the target component number, temperature parameters, retest results, and historical records, and realize data transmission. The result display and interaction unit 43 is used to output the measurement status, temperature correction information, and retest results to the display screen 21.

[0038] Specifically, the coarse positioning structure includes an electromagnet 33, a V-shaped positioning support 35, and a lockable anti-slip wheel 32. The electromagnet 33 is movably mounted on the lockable anti-slip wheel 32 through an axial position adjustment mechanism. The V-shaped positioning support 35 is movably mounted on the lockable anti-slip wheel 32 through a height adjustment mechanism. The lockable anti-slip wheel 32 is slidably mounted on the reference clamping base 27. The electromagnet 33 is electrically connected via a wire to an electromagnet 33 control switch 34 for controlling the start and stop of the electromagnet 33.

[0039] The lockable anti-slip wheel 32 is used to achieve the sliding and locking fixation of the coarse positioning structure on the reference clamping base 27; the electromagnet 33 is used to attract the outer end face of the target flange 36 or the adjacent ferromagnetic reference surface, providing the device fixing force and anti-reaction force basis, and can adapt to different flange 36 surface conditions; the electromagnet 33 control switch 34 is used to control the on and off state of the electromagnet 33; the V-shaped positioning support 35 is used to rise to the vicinity of the target component after the electromagnet 33 attracts and positions it, so that the target component enters the V-shaped surface of the V-shaped positioning support 35, and the V-shaped surface abuts against the outer wall of the target component, thereby achieving coarse positioning of the target component and restricting the lateral displacement and rotation of the target component. The coarse positioning structure, through the support of the reference clamping base 27, the attraction and fixation of the electromagnet 33, the coarse positioning of the V-shaped positioning support 35, and the bottom locking, jointly establishes a stable installation reference for the detection device relative to the target component, and provides anti-reaction force support for the constant pressure contact of the front ultrasonic transducer component 4 with the exposed end face of the target component.

[0040] More specifically, the axial position adjustment mechanism includes a mounting base, a first screw, and a first sliding seat. The first sliding seat is slidably connected to the mounting base, and the first screw is rotatably connected to the mounting base. The axial direction of the first screw and the sliding direction of the first sliding seat are both arranged along the axial direction of the ultrasonic transducer assembly 4. The first sliding seat is threadedly connected to the first screw, and the electromagnet 33 is fixed to the first sliding seat. The height adjustment mechanism includes a second screw and a second sliding seat. The second screw is rotatably connected to the mounting base, and the second sliding seat is slidably connected to the mounting base. The sliding directions of the second screw and the second sliding seat are arranged along the height direction. The second sliding seat is threadedly connected to the second screw, and the V-shaped positioning support 35 is fixed to the second sliding seat. The lockable anti-slip wheel 32 is located at the bottom of the mounting base. One end of the first screw is provided with an axial adjustment knob 30, and one end of the second screw is provided with a height adjustment knob 31. The first screw is rotated by the axial adjustment knob 30, and the second screw is rotated by the height adjustment knob 31.

[0041] The axial position adjustment mechanism can realize the axial position adjustment of the electromagnet 33, and the height adjustment mechanism can realize the height adjustment of the V-shaped positioning support 35, and is not limited to the above structural forms.

[0042] A self-centering detection method for in-situ retesting of ultrasonic preload of bolts includes the following steps: S1. Determine the target component based on the connection part of the flange 36 to be tested. The target component is a target stud or a target bolt. Move the self-centering detection device to the vicinity of the exposed end of the target component. S2. Place the front end of the reference clamping base 27 against the outer end face of the flange 36 to be tested, adjust the relative distance between the coarse positioning structure and the flange 36 to be tested by the lockable anti-slip wheel 32, and adjust the support height and installation posture of the front end of the device by the height adjustment support foot 26. S3. Adjust the extension position of the electromagnet 33 through the axial position adjustment mechanism so that the electromagnet 33 is in contact with the outer end face of the flange 36 to be tested; activate the control switch 34 of the electromagnet 33 so that the coarse positioning structure is adsorbed and fixed on the surface of the flange 36 to be tested. S4. Adjust the V-shaped positioning support 35 through the height adjustment mechanism so that the V-shaped positioning support 35 rises to the outer contour of the exposed end of the target component and places the exposed end of the target component in the V-shaped positioning surface of the V-shaped positioning support 35 to form a limiting fit and achieve coarse positioning of the target component. S5. After completing the reference clamping and coarse positioning, push the front self-centering detection execution area close to the exposed end of the target component. The exposed end of the target component first enters the open self-centering guide sleeve 3. Under the combined action of the guide cone surface 1 and the arc guide surface 2, the outer contour of the target component and the open self-centering guide sleeve 3 form a guiding fit, so that the measurement axis of the ultrasonic transducer 4 tends to coincide with the axis of the target component. S6. After completing the self-centering alignment, the contact pressure between the ultrasonic transducer assembly 4 and the exposed end face of the target component is set by the pre-pressure adjustment knob 10; the mid-section force transmission and loading zone guides the front-end measuring structure to move smoothly along the axial direction of the target component through the upper guide rod 11, auxiliary guide rod 13, lower guide rod 25, guide slide 12 and force transmission rod 14; the stroke limit adjustment knob 15 and stroke limit seat 23 limit the axial movement stroke of the front-end measuring end; Specifically, one end of the travel limit adjustment knob 15 is fixed with a screw, and the travel limit seat 23 is provided with a threaded hole. The screw is threaded into the threaded hole, and the axial direction of the screw is consistent with the radial direction of the auxiliary guide rod 13. Under normal conditions, the travel limit adjustment knob 15 is in the tightened state, and the end of the screw away from the travel limit adjustment knob 15 is pressed against the auxiliary guide rod 13. At this time, the travel limit seat 23 is fixed on the auxiliary guide rod 13. When it is necessary to adjust the travel limit, the travel limit adjustment knob 15 is loosened to make the screw leave the auxiliary guide rod 13. At this time, the travel limit seat 23 can slide. By sliding the travel limit seat 23, the distance between it and the limit plate is adjusted to limit the driving range of the force transmission rod 14, thereby limiting the axial movement of the front measuring end and avoiding pressure overload through hard limiting. The front-end self-centering detection actuator is slidably mounted on the pre-pressure loading seat 9. A loading screw is rotatably connected inside the pre-pressure loading seat 9. The axial direction of the loading screw and the sliding direction of the front-end self-centering detection actuator are the same as the axial direction of the ultrasonic transducer assembly 4. One end of the loading screw is threadedly connected to the front-end self-centering detection actuator, and the other end of the loading screw is connected to the pre-pressure adjustment knob 10 through a bevel gear set. By rotating the pre-pressure adjustment knob 10, the loading screw is driven to rotate, causing the front-end self-centering detection actuator to slide under the action of the loading screw thread, thereby moving the ultrasonic transducer assembly 4 away from or closer to the target component, thus realizing the adjustment of the pre-pressure.

[0043] S7. During the measurement process, the coupling medium in the coupling fluid storage chamber 53 is delivered to the vicinity of the probe working end face 44 through the micro-coupling fluid delivery conduit 54 and the coupling fluid spray outlet 55, so that a thin coupling interface is formed between the probe working end face 44 and the exposed end face of the target component. Under the control of the back-end main control processing unit 40, the piezoelectric crystal 49 emits ultrasonic signals and receives echo signals propagating along the axial direction of the target component; the temperature acquisition contact 37, the temperature sensor array, and the signal conversion cavity 50 synchronously acquire temperature parameters of the area adjacent to the target component; the back-end operation and processing area receives, amplifies, filters, and extracts time parameters of the echo signals through the ultrasonic signal acquisition and conditioning unit 41 to obtain the retest parameters of the target component's pre-tightening state; the main control processing unit 40 corrects the retest results in conjunction with the temperature parameters, and outputs the measurement status, temperature parameters, retest results of the pre-tightening state, and target component information through the display screen 21 and the result display and interaction unit 43; the data storage and communication unit 42 is used to save the target component number, temperature parameters, retest results, and historical records; S8. After completing the retest of the current target component, turn off the control switch 34 of the electromagnet 33 to release the electromagnetic adsorption, lower the V-shaped positioning support 35, and move the device to the position of the next target component column for retesting.

[0044] The specific embodiments of the present invention have been described in detail above with reference to the figures, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A self-centering testing device for in-situ retesting of ultrasonic preload of bolts, comprising a reference clamping base (27), characterized in that: The reference clamping base (27) is equipped with a front-end self-centering detection and execution mechanism, a middle-section force transmission and loading mechanism and a rear-end operation and processing mechanism connected sequentially along the axial direction; a coarse positioning structure is also slidably installed on the reference clamping base (27); The front-end self-centering detection actuator is used to realize the introduction, self-centering, temperature acquisition, local coupling, and ultrasonic retesting of the exposed end of the target component; the middle-section force transmission and loading mechanism is used to realize the pre-pressure application, constant pressure loading, and stroke limitation of the front-end measurement structure; the rear-end operation and processing mechanism is used to complete ultrasonic signal acquisition, temperature correction, result display, and data storage.

2. The self-centering detection device for in-situ retesting of ultrasonic preload of bolts according to claim 1, characterized in that: The front-end self-centering detection actuator includes an open-type self-centering guide sleeve (3), an ultrasonic transducer assembly (4), and a front-end probe mounting base (5). The rear end of the ultrasonic transducer assembly (4) is detachably connected to the front probe mounting base (5) via a quick-change interface (6), and its front end is located inside the open self-centering guide sleeve (3). The open-type self-centering guide sleeve (3) has a semi-enclosed structure with an open front end. Its front end is connected to an arc guide surface (2), and the front end of the arc guide surface (2) is connected to an inlet cone surface (1). The inner diameter of the inlet cone surface (1) gradually decreases from the arc guide surface (2) towards the front end. The ultrasonic transducer assembly (4) is coaxially arranged with the open-type self-centering guide sleeve (3). The ultrasonic transducer (4) is connected to one end of a cable (8) via a signal and power transmission interface (7), and the other end of the cable (8) is connected to the back-end operation and processing mechanism.

3. The self-centering detection device for in-situ retesting of ultrasonic preload of bolts according to claim 2, characterized in that: The ultrasonic transducer assembly (4) includes a probe housing (48), a piezoelectric crystal (49) is provided inside the probe housing (48), a matching layer (47) is provided at the front end of the piezoelectric crystal (49), and a temperature sensor array and a signal conversion cavity (50) are provided at the rear end of the piezoelectric crystal (49). The front end of the matching layer (47) is covered with a wear-resistant protective layer (45), and the outer end face of the front end of the wear-resistant protective layer (45) is the working end face (44) of the probe; the wear-resistant protective layer (45) is provided with a coupling liquid spray outlet (55). The probe housing (48) has a coupling fluid storage chamber (53) located at the rear end near the temperature sensor array and signal conversion cavity (50). The coupling fluid storage chamber (53) is connected to the coupling fluid spray outlet (55) through a micro-coupling fluid delivery conduit (54). The temperature sensor array and signal conversion cavity (50) are connected to the back-end operation and processing mechanism via signal lead-out lines (51); The probe housing (48) has a temperature acquisition contact (37) on the outer side of its front end, and the temperature acquisition contact (37) is connected to the temperature sensor array and the signal conversion cavity (50).

4. The self-centering detection device for in-situ retesting of ultrasonic preload of bolts according to claim 3, characterized in that: The mid-section force transmission and loading mechanism includes a preload loading seat (9), a guide slide (12) and a stroke limit seat (23) connected in sequence along the direction away from the front-end self-centering detection and execution mechanism. The preload loading seat (9) and the guide slide (12) are connected by an upper guide rod (11) and a lower guide rod (25) arranged in parallel. The rear operation and processing mechanism is provided with an auxiliary guide rod (13) and a force transmission rod (14) for driving the guide slide (12) to slide. The guide slide (12) is slidably mounted on the auxiliary guide rod (13). The end of the guide slide (12) away from the preload seat (9) is connected to the force transmission rod (14). The axial direction of the auxiliary guide rod (13) is consistent with the driving direction of the force transmission rod (14). The auxiliary guide rod (13) is parallel to the upper guide rod (11) and the lower guide rod (25). The auxiliary guide rod (13) is provided with a travel limit seat (23) that can slide and lock along the auxiliary guide rod (13). The travel limit seat (23) is located between the guide slide (12) and the rear operation and processing mechanism. A limit plate is fixed at one end of the auxiliary guide rod (13) away from the travel limit seat (23).

5. The self-centering detection device for in-situ retesting of ultrasonic preload of bolts according to claim 4, characterized in that: The preloaded loading seat (9) is connected to the upper end of the front support arm (28) via the front loading connecting seat (29), and the lower end of the front support arm (28) is connected to the reference clamping base (27) via the height adjustment support foot (26).

6. The self-centering detection device for in-situ retesting of ultrasonic preload of bolts according to claim 4, characterized in that: The rear operation and processing mechanism is fixed with a slide side limit block (24), which is located on both sides of the guide slide (12).

7. The self-centering detection device for in-situ retesting of ultrasonic preload of bolts according to claim 4, characterized in that: The back-end operation and processing mechanism is the main control processing host. The main control processing host is connected to the auxiliary guide rod (13) and the force transmission rod (14) through the host connector (16) and the host front end connector (22). The main control processing host includes a main control processing host shell (20) and a back end connector (19). The main control processing host shell (20) is provided with function buttons (18), a display screen (21) and a lifting handle (17).

8. The self-centering detection device for in-situ retesting of ultrasonic preload of bolts according to claim 7, characterized in that: The back-end operation and processing mechanism includes a power supply unit (38), a function control unit (39), a main control processing unit (40), an ultrasonic signal acquisition and conditioning unit (41), a data storage and communication unit (42), and a result display and interaction unit (43). The power supply unit (38) is electrically connected to the cable (8), the force transmission rod (14), the function control unit (39), the main control processing unit (40), the ultrasonic signal acquisition and conditioning unit (41), the data storage and communication unit (42), the result display and interaction unit (43), the function button (18), and the display screen (21), respectively; the function control unit (39) is connected to the function button (18) and the main control processing unit (40), respectively; the main control processing unit (40) is connected to the force transmission rod (14), the ultrasonic signal acquisition and conditioning unit (41), the data storage and communication unit (42), the result display and interaction unit (43), the function button (18), and the display screen (21), respectively; the ultrasonic signal acquisition and conditioning unit (41) is connected to the signal lead-out line (51); the data storage and communication unit (42) is connected to the rear connection port.

9. A self-centering detection device for in-situ retesting of ultrasonic preload of bolts according to claim 8, characterized in that: The coarse positioning structure includes an electromagnet (33), a V-shaped positioning support (35), and a lockable anti-slip wheel (32). The electromagnet (33) is movably mounted on the lockable anti-slip wheel (32) through an axial position adjustment mechanism. The V-shaped positioning support (35) is movably mounted on the lockable anti-slip wheel (32) through a height adjustment mechanism. The lockable anti-slip wheel (32) is slidably mounted on the reference clamping base (27). The electromagnet (33) is electrically connected via a wire to an electromagnet (33) control switch (34) for controlling the start and stop of the electromagnet (33).

10. A self-centering detection method for in-situ retesting of ultrasonic preload of bolts, implemented based on the self-centering detection device for in-situ retesting of ultrasonic preload of bolts as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Determine the target component based on the connection part of the flange (36) to be tested. The target component is the target stud or the target bolt. Move the self-centering detection device to the vicinity of the exposed end of the target component. S2. Place the front end of the reference clamping base (27) against the outer end face of the flange to be tested (36), adjust the relative distance between the coarse positioning structure and the flange to be tested (36) by using the lockable anti-slip wheel (32), and adjust the support height and installation posture of the front end of the device by using the height adjustment support foot (26). S3. Adjust the extension position of the electromagnet (33) through the axial position adjustment mechanism so that the electromagnet (33) is in contact with the outer end face of the flange (36) to be tested; start the control switch (34) of the electromagnet (33) so that the coarse positioning structure is adsorbed and fixed on the surface of the flange (36) to be tested. S4. Adjust the V-shaped positioning support (35) through the height adjustment mechanism to raise the V-shaped positioning support (35) to the outer contour of the exposed end of the target component, and place the exposed end of the target component in the V-shaped positioning surface of the V-shaped positioning support (35) to form a limiting fit and achieve coarse positioning of the target component. S5. After completing the reference clamping and coarse positioning, push the front self-centering detection execution area close to the exposed end of the target component. The exposed end of the target component first enters the open self-centering guide sleeve (3). Under the combined action of the guide cone surface (1) and the arc guide surface (2), the outer contour of the target component and the open self-centering guide sleeve (3) form a guiding fit, so that the measurement axis of the ultrasonic transducer assembly (4) tends to coincide with the axis of the target component. S6. After completing the self-centering alignment, the contact pressure between the ultrasonic transducer assembly (4) and the exposed end face of the target component is set by the pre-pressure adjustment knob (10); the middle section force transmission and loading zone guides the front-end measuring structure to move smoothly along the axial direction of the target component through the upper guide rod (11), auxiliary guide rod (13), lower guide rod (25), guide slide (12) and force transmission rod (14); the stroke limit adjustment knob (15) and stroke limit seat (23) limit the axial movement stroke of the front-end measuring end; S7. During the measurement process, the coupling medium in the coupling fluid storage chamber (53) is sent to the vicinity of the probe working end face (44) through the micro-coupling fluid delivery conduit (54) and the coupling fluid spray outlet (55), so that a thin coupling interface is formed between the probe working end face (44) and the exposed end face of the target component. The piezoelectric crystal (49) emits ultrasonic signals under the control of the back-end main control processing unit (40) and receives the echo signals after propagating along the axis of the target component; the temperature acquisition contact (37), temperature sensor array and signal conversion cavity (50) synchronously acquire the temperature parameters of the area adjacent to the target component; the back-end operation and processing area receives, amplifies, filters and extracts time parameters of the echo signals through the ultrasonic signal acquisition and conditioning unit (41) to obtain the retest parameters of the pre-tightening state of the target component; the main control processing unit (40) corrects the retest results in combination with the temperature parameters, and outputs the measurement status, temperature parameters, retest results of the pre-tightening state and target component information through the display screen (21) and the result display and interaction unit (43); the data storage and communication unit (42) is used to save the target component number, temperature parameters, retest results and historical records; S8. After completing the retest of the current target component, turn off the control switch (34) of the electromagnet (33), release the electromagnetic adsorption, lower the V-shaped positioning support (35), and move the device to the position of the next target component column for retest.

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