Magnetic bolt stress detection sensor and stress detection system

Abstract

The utility model provides a magnetic bolt stress detection sensor and a stress detection system. The magnetic bolt stress detection sensor comprises a sensor body and a pushing assembly, the sensor body comprises a detection part and a sensing head part; the detection part is arranged on a bolt in a sleeving manner and is connected with the bolt in a sliding manner; the sensing head part is fixed at the end part of the bolt; the pushing assembly is connected with the detection part and used for pushing the detection part to move in the axial direction of the bolt until the detection part is attached to the nut so that the detection part can detect the stress of the joint of the bolt and the nut. According to the embodiment of the utility model, the magnetic bolt stress detection sensor can be arranged on the end part of the bolt, and the detection part can move along the axial direction of the bolt, so that the detection part can be attached to a nut, and the stress state can be accurately monitored.

Description

Technical Field

[0001] This utility model relates to the field of bolt stress detection technology, and in particular to a magnetic bolt stress detection sensor and a stress detection system. Background Technology

[0002] Ultrasonic stress monitoring can be applied to non-destructive online monitoring of important bolts and other rod-like structures in power units, sensing the stress state of equipment in real time and providing real-time early warnings for faults such as abnormally low stress levels (e.g., warnings of loosening, fatigue fracture). Currently, ultrasonic bolt non-destructive force measurement technology based on the principle of metal acoustic spring is commonly used, employing magnetic fixation to monitor the bolts of in-service equipment. Existing magnetic sensor housings embed magnets, which attract the bolt ends. However, during on-site installation, due to the relatively long remaining bolt extension of tailrace gates or spiral gates in power plants, the magnets embedded in the magnetic sensor housing cannot engage with the nuts, making accurate monitoring impossible. Utility Model Content

[0003] In view of the above problems, this utility model is proposed to provide a magnetic bolt stress detection sensor and a stress detection system that overcome or at least partially solve the above problems.

[0004] To address the aforementioned problems, in the first aspect of this utility model, a magnetic bolt stress detection sensor is disclosed, which is installed at the end of a bolt, wherein the bolt is threadedly connected to a nut. The magnetic bolt stress detection sensor structure includes: a sensor body and a pushing assembly.

[0005] The sensor body includes a detection part and a sensing head; the detection part is sleeved on the bolt and slidably connected to the bolt; the sensing head is fixed to the end of the bolt.

[0006] The pushing component is connected to the detection unit and is used to push the detection unit to move along the axial direction of the bolt until it fits against the nut, so that the detection unit can detect the stress at the connection between the bolt and the nut.

[0007] Optionally, the detection unit includes a ring magnet, the inner ring of which is sleeved on the bolt and slidably connected to the bolt.

[0008] Optionally, the pushing component includes a pushing strut assembly.

[0009] The pusher support assembly is connected to the detection unit and protrudes from the detection unit.

[0010] Optionally, the pusher support group includes multiple pusher supports, which are evenly distributed along the circumferential direction.

[0011] Optionally, the number of the propulsion struts is even.

[0012] Optionally, the propulsion support is a light column.

[0013] The light beam is fixedly connected to the detection unit, and the detection unit moves along the axial direction of the bolt by pushing the light beam.

[0014] Optionally, the pusher has an external drive thread, and the detection part has an internal drive thread that matches the external drive thread, with the external drive thread coupled to the internal drive thread; the detection part is driven to move axially along the bolt by rotating the pusher.

[0015] Optionally, the bolt and the nut are connected to the tailgate.

[0016] Optionally, the bolt and the nut are connected to the volute door.

[0017] In a second aspect, this utility model discloses a stress detection system, including the magnetic bolt stress detection sensor as described above.

[0018] Optionally, it can be used to detect the bolt stress of a volute door.

[0019] Optionally, it can be used to detect the bolt stress of the tailgate.

[0020] Optionally, it further includes: a signal conditioning module, a data acquisition and processing unit, a power supply module, a display and alarm device, and a communication module; the signal conditioning module, the data acquisition and processing unit, the power supply module, the display and alarm device, and the communication module are respectively electrically connected to the magnetic bolt stress detection sensor.

[0021] This utility model has the following advantages:

[0022] This utility model embodiment is installed at the end of a bolt, which is threadedly connected to a nut. It consists of a sensor body and a pushing assembly. The sensor body includes a detection part and a sensing head. The detection part is sleeved on the bolt and slidably connected to it. The sensing head is fixed to the end of the bolt. The pushing assembly is connected to the detection part and is used to push the detection part along the axial direction of the bolt until it adheres to the nut, so that the detection part can detect the stress at the bolt-nut connection. After the sensing head of the sensor body is fixed to the end of the bolt, the pushing assembly pushes the detection part to adhere to the nut, achieving axial adsorption. This allows for stress detection at the bolt-nut connection, enabling accurate monitoring of stress conditions and timely issuance of early warning information. Attached Figure Description

[0023] Figure 1 This is a structural schematic diagram of a magnetic bolt stress detection sensor according to the present invention;

[0024] Figure 2 This is an exploded view of the structure of a magnetic bolt stress detection sensor according to this utility model;

[0025] Figure 3 This is a schematic diagram illustrating the application and deployment of a magnetic bolt stress detection sensor according to this utility model.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1- Bolt, 2- Nut, 3- Tailgate, 4- Magnetic bolt stress detection sensor;

[0028] 100 - Sensor body, 110 - Detection unit, 120 - Sensor head;

[0029] 200 - Propulsion component, 210 - Propulsion support. Detailed Implementation

[0030] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Ultrasonic stress monitoring can be applied to non-destructive online monitoring of important bolts and other rod-like structures in power units. It allows for real-time sensing of the equipment's stress state and provides real-time warnings of faults such as abnormally low stress levels (e.g., loosening, fatigue fracture), improving equipment safety and reliability. Typically, ultrasonic bolt non-destructive force measurement technology based on the principle of acoustic springs is used, employing magnetic fixation. The bolts to be monitored in in-service equipment do not need to be disassembled or replaced. Furthermore, the sensor is easy to install and disassemble, and different bolts can be easily replaced after installation. It is easy to install and maintain, has high accuracy, and allows for future upgrades to improve the accuracy of online bolt stress monitoring. Existing magnetic sensor housings embed magnets, which attract the bolt ends. During field installation, some power plant tailrace gates or spiral gate bolts have excessively long protruding bolts, preventing the embedded magnets from engaging with the nuts. To address these issues, this utility model embodiment is proposed.

[0032] Reference Figure 1 The diagram shows a structural schematic of a magnetic bolt stress detection sensor according to this utility model. (Refer to...) Figure 2The diagram shows an exploded view of the structure of a magnetic bolt stress detection sensor according to the present invention. The magnetic bolt stress detection sensor 4 is installed at the end of a bolt 1. The bolt 1 is threadedly connected to a nut 2. The magnetic bolt stress detection sensor 4 may specifically include the following components: sensor body 100 and push assembly 200.

[0033] The sensor body 100 includes a detection part 110 and a sensing head 120; the detection part 110 is sleeved on the bolt 1 and is slidably connected to the bolt 1; the sensing head 120 is fixed to the end of the bolt 1.

[0034] The pushing component 200 is connected to the detection unit 110 and is used to push the detection unit 110 to move along the axial direction of the bolt 1 until it fits against the nut 2, so that the detection unit 110 can detect the stress at the connection between the bolt 1 and the nut 2.

[0035] Bolt 1 passes through the through hole of the component to be fixed and is threadedly connected to nut 2. The component to be fixed is fixed through the threaded connection of bolt 1 and nut 2. The magnetic bolt stress detection sensor 4 includes a sensor body 100 and a pushing assembly 200. The sensor body 100 is the part that monitors stress, used to monitor the stress between nut 2 and bolt 1. The sensor body 100 includes a detection part 110 and a sensing head 120. The detection part 110 is used for stress detection. The sensing head 120 is used to transmit the stress value detected by the detection part 110 to the corresponding system. The detection part 110 can be sleeved on bolt 1 and slidably connected to bolt 1; it can move along the axial direction of bolt 1. The sensing head 120 is fixed to the end of bolt 1, thus allowing the sensor body 100 to be installed into bolt 1. The pushing assembly 200 can push the detection part 110 to move along the axial direction of bolt 1. The pushing assembly 200 is connected to the detection part 110, and the pushing assembly 200 can be directly operated by the operator, or the operator can operate the pushing assembly 200 using equipment. By operating the push assembly 200, the push assembly 200 pushes the detection part 110 to move along the axial direction of the bolt 1 until it fits against the nut 2, thereby allowing the detection part 110 to be adsorbed onto the nut 2 and the stress at the connection between the bolt 1 and the nut 2 to be detected.

[0036] This embodiment of the invention uses a sensor body 100 and a pushing assembly 200, mounted on the end of a bolt 1, which is threadedly connected to a nut 2. The sensor body 100 includes a detection part 110 and a sensing head 120. The detection part 110 is sleeved on the bolt 1 and slidably connected to it. The sensing head 120 is fixed to the end of the bolt 1. The pushing assembly 200 is connected to the detection part 110 and is used to push the detection part 110 along the axial direction of the bolt 1 until it fits against the nut 2, so that the detection part 110 can detect the stress at the connection between the bolt 1 and the nut 2. After the sensing head 120 of the sensor body 100 is fixed to the end of the bolt 1, the pushing assembly 200 pushes the detection part 110 to fit against the nut 2, achieving axial adsorption. This allows for stress detection at the connection between the bolt 1 and the nut 2, enabling accurate monitoring of stress and timely issuance of early warning information.

[0037] In one embodiment of the present invention, the detection unit 110 includes an annular magnet, the inner ring of which is sleeved on the bolt 1 and slidably connected to the bolt 1.

[0038] The detection unit 110 includes a ring magnet. Based on the magnetoelastic effect and changes in magnetic circuit characteristics, the ring magnet indirectly reflects the stress state by measuring changes in the magnetization characteristics (such as permeability and magnetic reluctance) of the bolt 1. The inner ring of the ring magnet is slidably connected to the bolt 1. After the ring magnet is attached to the nut 2, the stress is determined based on the detected magnetization characteristics. That is, the magnetization characteristics of the bolt 1 change under stress. When the bolt 1 is subjected to tensile or compressive stress, the permeability of the material changes accordingly. Tensile stress makes it easier to magnetize the bolt 1, increasing the permeability. Compressive stress makes it more difficult to magnetize the bolt 1, decreasing the permeability. The change in the permeability of the bolt 1 leads to a change in its magnetic reluctance. Magnetic reluctance is inversely proportional to permeability. The change in magnetic reluctance causes a change in magnetic flux density, which in turn affects the magnetic induction electromotive force. The stress is determined based on the magnetic induction electromotive force.

[0039] In one embodiment of this utility model, the pushing component 200 includes a pushing support assembly.

[0040] The push support assembly is connected to the detection unit 110 and protrudes from the detection unit 110.

[0041] The pushing assembly 200 includes a pushing support assembly, which is connected to and protrudes from the detection part 110, making it easy for operators to operate the pushing support assembly to push the detection part 110 to move, so that the detection part 110 fits against the nut 2.

[0042] In one embodiment of the present invention, the pusher support group includes multiple pusher supports 210, which are evenly distributed along the circumferential direction.

[0043] In this embodiment of the utility model, the push support assembly may include multiple push supports 210. The multiple push supports 210 may be evenly distributed along the circumferential direction of the detection part 110. That is, the push supports 210 are equally spaced along the circumferential direction of the detection part 110. So when the push assembly 200 pushes the detection part 110, the detection part 110 can be evenly stressed, so that the lower plane can move evenly toward the nut 2, so that the detection part 110 can better fit the nut 2.

[0044] Furthermore, the number of the pushing supports 210 is even. The even-numbered pairs of pushing supports 210 can symmetrically push the detection part 110 to move along the axial direction of the bolt 1 in the sub-circumferential direction, avoiding the situation where the detection part 110 is tilted when it is in contact with the nut 2, thereby enabling accurate stress detection.

[0045] In one embodiment of this utility model, the pushing support 210 is a light column.

[0046] The light beam is fixedly connected to the detection unit 110, and the detection unit 110 is moved along the axial direction of the bolt 1 by pushing the light beam.

[0047] In this embodiment of the invention, the pushing support 210 is a light column, that is, a column with a smooth outer surface, and the light column is fixedly connected to the detection part 110. The light column and the detection part 110 can be integrally formed. By pressing and pushing these pushing supports 210, the pushing support 210 and the detection part 110 can be moved integrally along the axial direction of the bolt 1 towards the nut 2, as shown. Figure 1 The device moves downwards until it contacts and adheres to the nut 2. Then, the nut 2 is added to the tail end of the push column 210 to define its position. Thus, the movement of the detection unit 110 can be achieved by squeezing and pushing, so that the detection unit 110 fits against the nut 2.

[0048] In one embodiment of the present invention, the push support 210 has a transmission external thread, and the detection part 110 has a transmission internal thread that matches the transmission external thread, and the transmission external thread is coupled with the internal thread; by rotating the push support 210, the detection part 110 is pushed to move along the axial direction of the bolt 1.

[0049] In this embodiment of the invention, the outer surface of the push column 210 has a drive external thread, while the inside of the detection part 110 has a drive internal thread hole. The drive internal threads match each other. The drive external thread of the push column 210 and the drive internal thread of the detection part 110 are coupled to each other. The thread profile, pitch, and other parameters can be determined according to the actual situation, and this embodiment of the invention does not impose specific limitations. The detection part 110 can be moved axially along the bolt 1 by rotating the push column 210. That is, the drive external thread on the surface of the column engages with the drive internal thread of the detection part 110. By rotating the push column 210, the push column 210 and the detection part 110 are moved downward as a whole until the detection part 110 contacts and adheres to the nut 2. Thus, the movement of the detection part 110 can be achieved by rotation, so that the detection part 110 fits against the nut 2.

[0050] In one embodiment of this utility model, the bolt 1 and the nut 2 are connected to the tailgate 3.

[0051] You can refer to Figure 3 Bolt 1 and nut 2 are connected to the tailrace gate 3 to fix the tailrace gate 3 in place and to check the stress on the tailrace gate 3. The tailrace gate 3 is the tailrace gate in the hydropower station. It is used to regulate the water level, control the water flow, protect the downstream ecological environment, and ensure the safe operation of the hydropower station. The tailrace gate 3 can be a tailrace quick gate, used to quickly cut off the water flow in emergencies to prevent the unit from running away. The tailrace emergency gate slides down and closes in the event of a hydropower unit failure or runaway, cutting off the water flow and preventing the accident from escalating. The maintenance gate: it blocks the downstream tailrace water during unit maintenance to provide maintenance conditions. The operation of the tailrace gate 3 includes dynamic water closure and static water opening and closing, as well as a hydraulic opening and closing system. Dynamic water closure and static water opening and closing include withstanding water pressure from the lower reservoir during normal operation of the gate. To prevent the gate from being damaged by accidental water pressure from the upper reservoir when it is fully closed, the gate is equipped with an automatic pressure relief device. Under normal circumstances, the gate is opened and closed in a static water state, and the horizontal pressure is filled by the bypass pipe. The hydraulic gate opening and closing system consists of a hydraulic cylinder and an independent hydraulic control valve assembly, operated by a local PLC (Programmable Logic Controller) control unit. The hydraulic gate opener has two independent power supplies to ensure reliable power supply. The hydraulic pump station equipment and local control cabinet are located in the centralized control room in the middle of the tailgate opening.

[0052] In one embodiment of this utility model, the bolt 1 and the nut 2 are connected to the volute door.

[0053] Bolt 1 and nut 2 are connected to the spiral gate to secure it in place and to check the stress on the tailrace gate 3. This spiral gate is installed within the turbine spiral casing structure. It is used for personnel to enter and exit the spiral casing for inspection, maintenance, or emergency operations. As a component of the spiral casing structure, the spiral gate must withstand internal and external water pressure, the structure's own weight, and potential dynamic loads. The spiral gate includes: a door panel, hinges and locking devices, and sealing and corrosion-resistant components. The door panel is typically made of high-strength steel or cast steel, and its thickness must meet the water pressure bearing requirements. The hinges and locking devices affect the door's stress distribution and ease of operation through the hinge arrangement (inward or outward opening); the locking devices ensure reliable sealing of the door under high pressure. Sealing and corrosion-resistant components include a sealing strip between the door and the door frame to prevent leakage; the surface must be treated with anti-corrosion measures (such as a coating or galvanized layer).

[0054] The functions and operation of the spiral casing door include: Inspection and maintenance: The spiral casing door provides maintenance personnel with access to the interior of the spiral casing, facilitating the inspection of components such as the inner wall, guide vanes, and impeller. During unit shutdown for maintenance, it is essential to ensure the door is properly sealed to prevent leakage. Emergency operation: In emergencies such as unit runaway or pipe rupture, the spiral casing door can serve as an emergency passage or isolation device. A quick-opening mechanism is required to ensure safe evacuation of personnel or emergency equipment handling. Sealing and pressure resistance: The spiral casing door must withstand the pressure difference between the inside and outside of the water; its sealing performance directly affects the safety of the power station. The sealing strip material must be water pressure resistant and corrosion resistant, and should be inspected and replaced regularly.

[0055] This utility model embodiment also discloses a stress detection system, including the magnetic bolt stress detection sensor 4 as described above. The stress detected by the magnetic bolt stress detection sensor 4 is processed to issue a corresponding warning signal when an abnormality occurs.

[0056] Furthermore, the stress detection system can be used to detect the bolt stress of a spiral-shaped door.

[0057] Furthermore, the stress detection system can be used to detect the bolt stress of the tailgate.

[0058] Furthermore, the stress detection system may include a magnetic bolt stress detection sensor 4, a signal conditioning module, a data acquisition and processing unit, a power supply module, a display and alarm device, and a communication module. The signal conditioning module, data acquisition and processing unit, power supply module, display and alarm device, and communication module are all electrically connected to the magnetic bolt stress detection sensor 4.

[0059] The magnetic bolt stress sensor 4 is magnetically attached to the surface of bolt 1. Utilizing magnetostriction, magnetoelasticity, or magnetic induction, it converts stress changes in bolt 1 into electrical signals (such as voltage, current, or frequency). The signal conditioning module amplifies, filters, and linearizes the weak electrical signal output by the sensor to improve the signal-to-noise ratio and stability, facilitating subsequent data acquisition and analysis. The data acquisition and processing unit uses a high-precision data acquisition card or microcontroller (MCU) to perform analog-to-digital conversion (ADC) on the conditioned signal and extracts stress feature values ​​using built-in algorithms (such as Fourier transform and wavelet analysis). The power supply module provides a stable operating voltage for the magnetic bolt stress sensor 4, the signal conditioning module, and the data acquisition unit, typically powered by a lithium battery or an external DC power adapter. The display and alarm device displays the stress value of bolt 1 in real time via its built-in LCD or digital tube. When the stress exceeds a preset threshold, an audible and visual alarm is triggered to alert the operator to take action. The communication module supports wired (such as RS-485, CAN bus) or wireless (such as LoRa, Wi-Fi, 4G / 5G) communication methods to upload stress data to a remote monitoring platform or cloud server, enabling remote monitoring and early warning.

[0060] The overall work process can include the following:

[0061] Sensor installation and initialization: The magnetic bolt stress detection sensor 4 is attached to the end of bolt 1, ensuring tight contact through magnetic force. After the system is powered on, it automatically performs zero-point calibration and sensitivity calibration to eliminate environmental interference and individual sensor differences.

[0062] The stress signal acquisition and processing involves a magnetic bolt stress sensor 4 that senses the stress changes in bolt 1 in real time and outputs an electrical signal to the signal conditioning module. The conditioned signal is converted into a digital signal by an ADC, and then the MCU performs feature extraction and filtering to calculate the real-time stress value of bolt 1.

[0063] Data storage and display: Stress data is stored in local memory (such as EEPROM or SD card) and displayed on an LCD screen showing the current stress value and historical trend graph. Users can set stress thresholds, and an alarm device is triggered when the detected value exceeds the limit.

[0064] Remote communication and monitoring are provided. The communication module uploads stress data to the cloud or local server, allowing users to view the status of bolt 1 in real time via a mobile app or web interface. The system supports multi-node networking, enabling simultaneous monitoring of stress distribution across multiple bolts 1.

[0065] For maintenance and diagnostics, the system has self-diagnostic capabilities, capable of detecting abnormalities such as sensor malfunctions and communication interruptions, and alerting maintenance personnel via indicator lights or remote notifications. Regular calibration and battery replacement ensure long-term stable operation of the system.

[0066] Among them, the magnetic bolt stress detection sensor 4 is installed at the end of the bolt 1, the bolt 1 is threadedly connected to the nut 2, and the structure of the magnetic bolt stress detection sensor 4 includes: sensor body 100 and push assembly 200.

[0067] The sensor body 100 includes a detection part 110 and a sensing head 120; the detection part 110 is sleeved on the bolt 1 and is slidably connected to the bolt 1; the sensing head 120 is fixed to the end of the bolt 1.

[0068] The pushing component 200 is connected to the detection unit 110 and is used to push the detection unit 110 to move along the axial direction of the bolt 1 until it fits against the nut 2, so that the detection unit 110 can detect the stress at the connection between the bolt 1 and the nut 2.

[0069] Optionally, the detection unit 110 includes a ring magnet, the inner ring of which is sleeved on the bolt 1 and slidably connected to the bolt 1.

[0070] Optionally, the pushing assembly 200 includes a pushing strut assembly.

[0071] The push support assembly is connected to the detection unit 110 and protrudes from the detection unit 110.

[0072] Optionally, the pusher support group includes multiple pusher supports 210, which are evenly distributed along the circumferential direction.

[0073] Optionally, the number of the pusher supports 210 is even.

[0074] Optionally, the pushing support 210 is a light column.

[0075] The light beam is fixedly connected to the detection unit 110, and the detection unit 110 is moved along the axial direction of the bolt 1 by pushing the light beam.

[0076] Optionally, the push support 210 has a transmission external thread, and the detection part 110 has a transmission internal thread that matches the transmission external thread, and the transmission external thread is coupled to the internal thread; by rotating the push support 210, the detection part 110 is pushed to move along the axial direction of the bolt 1.

[0077] Optionally, the bolt 1 and the nut 2 are connected to the tailgate 3.

[0078] Optionally, the bolt 1 and the nut 2 are connected to the volute door.

[0079] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0080] The above provides a detailed description of a magnetic bolt stress detection sensor and a stress detection system provided by this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A magnetic bolt stress detection sensor, characterized by, The magnetic bolt stress detection sensor structure is installed on the end of a bolt, the bolt is threadedly connected with a nut, and comprises a sensor body and a pushing assembly. The sensor body comprises a detection part and a sensing head part; the detection part is sleeved on the bolt and is slidably connected with the bolt; and the sensing head part is fixed on the end of the bolt. The pushing assembly is connected with the detection part and is used for pushing the detection part to move along the axial direction of the bolt until the detection part abuts against the nut, so that the detection part detects the stress at the connection position of the bolt and the nut.

2. The bolt stress detection sensor according to claim 1, characterized by, The detection part comprises a ring-shaped magnet, and an inner ring of the ring-shaped magnet is sleeved on the bolt and is slidably connected with the bolt.

3. The bolt stress detection sensor according to claim 1, characterized by, The pushing assembly comprises a pushing strut group, The pushing strut group is connected with the detection part and protrudes from the detection part.

4. The bolt stress detection sensor according to claim 3, characterized by The pushing strut group comprises a plurality of pushing struts, and the pushing struts are uniformly distributed in the circumferential direction.

5. The bolt stress detection sensor according to claim 4, characterized by The number of the pushing struts is even.

6. The bolt stress detection sensor according to claim 4, characterized by The pushing struts are light columns, The light columns are fixedly connected with the detection part and are used for driving the detection part to move along the axial direction of the bolt by pushing the light columns.

7. The bolt stress detection sensor according to claim 4, characterized by The pushing struts have transmission external threads, the detection part has transmission internal threads matched with the transmission external threads, and the transmission external threads are coupled with the internal threads; the detection part is pushed to move along the axial direction of the bolt by rotating the pushing struts.

8. The bolt stress detection sensor of claim 1, wherein, The bolt and the nut are connected to a draft tube gate.

9. The bolt stress detection sensor according to claim 1, characterized by, The bolt and the nut are connected to a volute gate.

10. A stress detection system characterized by, The magnetic bolt stress detection sensor comprises the magnetic bolt stress detection sensor according to any one of claims 1 to 9.

11. The stress detection system of claim 10, wherein, The magnetic bolt stress detection sensor is used for detecting the bolt stress of a volute gate.

12. The stress detection system of claim 10, wherein, The magnetic bolt stress detection sensor is used for detecting the bolt stress of a draft tube gate.

13. The stress detection system of claim 10, wherein, Further comprising: a signal conditioning module, a data acquisition and processing unit, a power module, a display and alarm device, and a communication module; the signal conditioning module, the data acquisition and processing unit, the power module, the display and alarm device, and the communication module are respectively electrically connected with the magnetic bolt stress detection sensor.

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