Bolt looseness monitoring device and bolt

Abstract

The invention discloses a bolt looseness monitoring device and a bolt. The device comprises an acquisition system, a main control system, a communication system and a terminal device, the acquisition system acquires bolt loosening data and sends the bolt loosening data to the main control system, and the bolt loosening data processed by the main control system is sent to the communication system and wirelessly transmitted to the terminal device by the communication system; wherein the acquisition system, the main control system and the communication system are integrated on a foldable flexible PCB (Printed Circuit Board), a preset crease is designed on the flexible PCB, and a nut style is formed after the flexible PCB is folded according to the crease. When the bolt is loosened, the monitoring system does not need to be disassembled, the system is fixed to the head of the bolt and can be firmly fastened to the head of the bolt under the action of gravity, and the risk that the system falls off is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of bolt loosening monitoring, in particular to a bolt loosening monitoring device and a bolt. Background Art

[0002] Most of the pot-type insulators on high-altitude overhead towers are fixed by bolts, which may become loose due to various reasons after long-term operation. At present, TMR magnetic sensors are used to detect bolt loosening. The principle is to use the high sensitivity and fast response of TMR tunnel magnetoresistive sensors to magnetic field signals. The bolt loosening detection device based on TMR magnetic sensors is characterized in that the monitoring device does not destroy the original connection structure, and the TMR sensor has stable magnetic measurement, extremely low noise, and extremely high accuracy in monitoring bolt loosening.

[0003] However, most bolt loosening monitoring devices now install the system on the nut. Not only does it need to be disassembled and reinstalled for maintenance when the bolt is loose, but in most bolt connection devices, the nut is at the bottom relative to the bolt head, which causes the bolt monitoring device connected to the nut to be affected by gravity at all times, and there is a risk of falling off.

[0004] In the prior art, the invention patent with the patent publication number CN117091499A discloses a bolt loosening angle sensor, which is provided with a bipolar magnet on the screw fixing assembly, and a monitoring module for monitoring the change of the magnetic field direction of the bipolar magnet on the nut fixing assembly, and monitors the loosening angle between the screw fixing assembly and the nut fixing assembly by monitoring the change of the magnetic field direction of the bipolar magnet. However, after detecting that the bolt is loose, it is necessary to disassemble the nut fixing assembly installed on the loose nut, and then tighten the loose bolt. Summary of the invention

[0005] The technical problem to be solved by the present invention is to solve the problem that a bolt loosening monitoring device needs to be disassembled and reassembled for later maintenance after detecting that the bolt is loose.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A bolt loosening monitoring device comprises a collection system, a main control system, a communication system and a terminal device; the collection system collects bolt loosening data and sends it to the main control system, the bolt loosening data processed by the main control system is then sent to the communication system, and the communication system wirelessly transmits it to the terminal device;

[0008] Among them, the acquisition system, main control system, and communication system are integrated on a foldable flexible PCB board, and the flexible PCB board is designed with pre-set creases, which form a nut style after folding along the creases.

[0009] In one embodiment of the present invention, the acquisition system includes a TMR sensor and a strong magnet; the chip of the TMR sensor is integrated on a flexible PCB board, and the strong magnet provides a targeted magnetic field for the TMR sensor.

[0010] In one embodiment of the present invention, the strong magnet is in the shape of a nut.

[0011] In one embodiment of the present invention, the TMR sensor measures the angle of rotation of the bolt loosening by measuring magnetic resistance:

[0012] R(θ)=RP+(RaP-RP)(1-cos0) / 2;

[0013]

[0014] In the formula, R(θ) represents the magnetic resistance at an angle of θ, θ represents the angle relative to the magnetization direction, and R P With R aP They are respectively represented as the resistance of the tunnel junction when the relative magnetization directions of the two ferromagnetic layers are parallel and antiparallel, V sinθ and V cosθ They respectively represent two voltage signals output by two orthogonal Wheatstone bridges integrated inside the TMR sensor chip.

[0015] In one embodiment of the present invention, a plurality of bolt loosening monitoring devices are connected to a relay system to form a monitoring system; the communication system in each bolt loosening monitoring device sends the bolt loosening data to the relay system via wireless transmission, and the relay system uploads the bolt loosening data to the terminal device.

[0016] In one embodiment of the present invention, the bolt loosening monitoring device includes a power supply system, which is connected to the acquisition system, the main control system, and the communication system and is integrated on a flexible PCB board.

[0017] In one embodiment of the present invention, when in use, a flexible PCB board forming a nut pattern is sleeved on the nut of the bolt, and a strong magnet is locked under the nut used with the bolt and threadedly connected with the stud of the bolt.

[0018] The present invention also provides a bolt, using the above-mentioned bolt loosening monitoring device, and a flexible PCB board forming a nut pattern is sleeved on the nut of the bolt.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention designs a bolt monitoring device fixed on the bolt head. Not only does it not need to disassemble the monitoring system when the bolt loosens, but the system is also fixed on the bolt head and will be firmly fastened on the bolt head under the action of gravity, reducing the risk of the system falling off.

[0021] Most of the bolt monitoring devices on the market are fixed on the nut, vertically downward, so that the bolt monitoring device is always affected by gravity, and there is a risk of falling off, or the bolt monitoring device and the nut are loose, resulting in inaccurate detection. The bolt monitoring device of the present invention is a hexagonal structure directly fixed on the upper part of the bolt. It is vertically downward under the action of gravity and will be firmly attached to the upper surface of the bolt. It will not loosen with the bolt under the influence of gravity, eliminating inaccurate detection, greatly delaying its monitoring time, and stability, and reducing the number of times the staff replaces the equipment.

[0022] The targeting magnetic field of the present invention is different from the circular or square targeting magnetic field on the market. The targeting magnetic field of the present invention is in the shape of a hexagonal nut, and is made of a strong magnetic material of neodymium iron boron, and has a thread, which is locked under the nut. The nuts used normally are made of rigid materials, and the suction of the two is not strong, while the materials fixed in the middle are mostly metal materials, which have a strong suction with the targeting magnet. The targeting magnet with loose bolts is fixed well, and the suction force on the structure is greater than the suction force on the nut above, so that there is an upward force, which always prevents the nut from loosening downward. While monitoring the loosening of the bolts, it can also effectively prevent the bolts from loosening, killing two birds with one stone.

[0023] The present invention has a universal hexagonal shape for both the bolt loosening detection device and the targeting magnet. When the bolt is loose, there is no need to disassemble the equipment and the bolt can be tightened using a conventional hexagonal wrench. This is different from other devices on the market, which do not require tedious steps of disassembly and tightening and reinstallation, greatly increasing work efficiency.

[0024] The present invention adopts a wireless transmission mode, which does not require an external power supply, the power consumption of the whole machine is extremely small, and it can work outdoors for more than one year. The wireless transmission mode has a wider application range and smaller limitations.

[0025] The present invention is equipped with a relay device, which can complete real-time detection of several loose monitoring devices. It is suitable for large equipment or equipment with bolt fastening devices, and does not need to be equipped with multiple PC terminals. The installation of the relay device can increase the transmission distance and communication distance to 1000m (up to 2000m in open outdoor areas), greatly increasing the scope of monitoring coverage. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of a bolt loosening monitoring device according to an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the hardware circuit of an embodiment of the present invention being integrated on a flexible PCB board.

[0028] Figure 3 Schematic diagram of a folded flexible PCB board according to an embodiment of the present invention.

[0029] Figure 4 Schematic diagram of a TMR magnetic tunnel junction according to an embodiment of the present invention.

[0030] Figure 5 Schematic diagram of a monitoring system according to an embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram of the use and installation of the monitoring device according to an embodiment of the present invention.

[0032] Figure 7 Schematic diagram of detecting different bolt loosening angles according to an embodiment of the present invention.

[0033] Figure 8 It is a schematic diagram showing a terminal device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described in conjunction with the accompanying drawings of the specification.

[0035] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0036] See also Figure 1 As shown, the present invention provides a bolt loosening monitoring device, including a collection system 10, a main control system 20, a communication system 30 and a terminal device 40. The collection system 10 collects bolt loosening data and sends it to the main control system 20. The bolt loosening data processed by the main control system 20 is then sent to the communication system 30, and the communication system 30 wirelessly transmits it to the terminal device 40.

[0037] See also Figures 1 to 3 As shown, in one embodiment of the present invention, the hardware of the entire monitoring device is integrated on a foldable flexible PCB board, and the flexible PCB board is designed with pre-set creases, which are folded along the creases to form a nut pattern.

[0038] In one embodiment of the present invention, the acquisition system includes a TMR sensor and a strong magnet, the chip of the TMR sensor is integrated on a flexible PCB board, the strong magnet is made of neodymium iron boron, provides a targeted magnetic field for the TMR sensor, and is in the shape of a nut. In addition, the acquisition system is also designed with a signal processing circuit, etc.

[0039] In this embodiment, when in use, the flexible PCB board formed into a nut pattern is sleeved on the nut of the bolt, and the strong magnet is locked under the nut used with the bolt and threadedly connected with the stud of the bolt.

[0040] In this embodiment, the basic unit of the TMR sensor is a magnetic tunnel junction (MTJ), as follows Figure 4 It includes a free layer and a reference layer made of ferromagnetic metal. These two layers sandwich a tunnel barrier layer in the middle, and the bottom pinning layer fixes the magnetization direction of the reference layer above. When there is no external magnetic field, the magnetic moments in the free layer are randomly arranged. When there is an external magnetic field and it changes, the direction of the magnetic moment in the free layer changes with the change of the external magnetic field, and the magnetic moment in the reference layer does not change. The electrons in the tunnel barrier layer between the two layers tunnel at this time, and the number of tunnels depends on the magnetization direction of the free layer and the reference layer. When the magnetization directions of the two layers are consistent, most spin electrons tunnel into the other ferromagnetic layer. At this time, the tunneling current is the largest and the resistance is the smallest. On the contrary, the tunneling current is the smallest and the resistance is the largest. The maximum resistance and minimum resistance are the working range of the TMR sensor. The change of the external magnetic field can be measured by measuring the change of magnetoresistance.

[0041] The bolt is fixed by rotation and tightening. When loosened, the bolt will not loosen straight up and down due to the limitation of the thread, but will loosen by rotation. A targeted magnetic field is fixed on the bolt. Under the influence of the magnetic field, the direction of the free layer magnetic moment of the MTJ unit in the TMR sensor changes with the magnetic field. The nut is fixedly connected to the magnet. When the bolt is loosened, the nut rotates, and the strong magnet rotates with the nut, causing relative rotation between the bolt and the strong magnet. The angle of the bolt's loosening rotation can be measured by measuring the magnetic resistance. The relationship between the magnetic resistance and the angle θ of the relative magnetization direction is shown in the following formula:

[0042] R(θ)=RP+(RuP-RP)(1-Cosθ) / 2;

[0043] In the formula, R(θ) represents the magnetic resistance at an angle of θ, θ represents the angle relative to the magnetization direction, and R P With R aP They are respectively represented as the resistance of the tunnel junction when the relative magnetization directions of the two ferromagnetic layers are parallel and antiparallel.

[0044] In actual engineering applications, the resistance value cannot be measured directly. The TMR sensor chip integrates two orthogonal Wheatstone bridges to output two signals, V sinθ and V cosθ , the angle θ relative to the magnetization direction can be obtained by the following formula:

[0045]

[0046] In this embodiment, the targeted magnetic field of the present invention is provided by a nut-type strong magnet, and its magnetization direction is axial magnetization, that is, it exhibits positive and negative poles in the axial direction, such as an upper N pole and a lower S pole. The magnetic effect of the targeted magnetic field can generate mutual attraction on the nut or metal structure in the upper and lower directions, so that the targeted magnetic field can be stably located on the bolt. And this kind of attraction can also reduce the rotation of the nut in the circumferential direction on the other hand, avoiding the occurrence of bolt loosening. Because the nut and the strong magnet are fixed, the two form a double nut structure, and the effect of pressure between the two can also play a role in strengthening the fastening between the nut and the bolt.

[0047] See also Figure 1 As shown, in one embodiment of the present invention, the bolt loosening monitoring device includes a power supply system 50, which is connected to the acquisition system, the main control system, and the communication system to power the monitoring device and is integrated on the flexible PCB board.

[0048] In this embodiment, the present invention does not limit the specific structures of the main control system 20, the communication system 30, the power supply system 50 and the terminal device 40, and the main structures of the main control chip, the communication system 30, the power supply system 50 and the terminal device 40 can be, for example, a mobile phone, a PC, a host computer, etc.

[0049] See also Figure 5 As shown, in one embodiment of the present invention, a plurality of bolt loosening monitoring devices are connected to a relay system 100 to form a monitoring system. The communication system 30 in each bolt loosening monitoring device sends the bolt loosening data to the relay system 100 by wireless transmission, and the relay system 100 uploads the bolt loosening data to the terminal device 40. Among them, the relay system 100 is equipped with a high-frequency communication module, which can greatly enhance the transmission distance.

[0050] See also Figure 6 As shown, in one embodiment of the present invention, when in use, the flexible PCB board A forming a nut pattern is sleeved on the nut 210 of the bolt, and the strong magnet B is locked under the nut 220 used in conjunction with the bolt, and is threadedly connected with the stud 230 of the bolt. The nut 220 in normal use is made of rigid material, and the suction force between the two is not strong, while the material 240 fixed in the middle is mostly made of metal material, and the suction force with the targeting magnet is stronger. The targeting magnet of the loose bolt is fixed well, and the suction force on the structure is greater than the suction force on the nut 210 above, so that there is an upward force, which always prevents the nut 210 from loosening downward. While monitoring the loosening of the bolt, it can also effectively prevent the bolt from loosening, killing two birds with one stone.

[0051] In one embodiment of the present invention, Figure 7The bolt loosening monitoring device shown in the figure detects bolt loosening angles from 30° to 360°. From the results, it can be seen that the accuracy of the system is 0.5°. Figure 8 The figure shows the final upper computer model diagram. From the figure, we can clearly see the angle of bolt loosening and prevent the adverse effects caused by bolt loosening.

[0052] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0053] The above-described embodiments merely represent implementation methods of the invention. The protection scope of the present invention is not limited to the above-described embodiments. For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A bolt loosening monitoring device, characterized in that: It includes a collection system, a main control system, a communication system and a terminal device; the collection system collects bolt loosening data and sends it to the main control system, and the bolt loosening data processed by the main control system is then sent to the communication system, which is then wirelessly transmitted to the terminal device by the communication system; Among them, the acquisition system, main control system, and communication system are integrated on a foldable flexible PCB board, and the flexible PCB board is designed with pre-set creases, which form a nut style after folding along the creases.

2. The bolt loosening monitoring device according to claim 1, characterized in that: The acquisition system includes a TMR sensor and a strong magnet; the chip of the TMR sensor is integrated on a flexible PCB board, and the strong magnet provides a targeted magnetic field for the TMR sensor.

3. The bolt loosening monitoring device according to claim 2, characterized in that: The strong magnet is in the shape of a nut.

4. The bolt loosening monitoring device according to claim 2, characterized in that: The TMR sensor measures the magnetic resistance to measure the angle of rotation of the bolt loosening: R(θ)=R P +(R aP -R P )(1-cosθ) / 2; In the formula, R(θ) represents the magnetic resistance at an angle of θ, θ represents the angle relative to the magnetization direction, and R P With R aP They are respectively represented as the resistance of the tunnel junction when the relative magnetization directions of the two ferromagnetic layers are parallel and antiparallel, V sinθ and V cosθ They respectively represent two voltage signals output by two orthogonal Wheatstone bridges integrated inside the TMR sensor chip.

5. The bolt loosening monitoring device according to claim 1, characterized in that: A plurality of bolt loosening monitoring devices are connected to a relay system to form a monitoring system; the communication system in each bolt loosening monitoring device sends the bolt loosening data to the relay system by wireless transmission, and the relay system uploads the bolt loosening data to the terminal device.

6. The bolt loosening monitoring device according to claim 1, characterized in that: The bolt loosening monitoring device includes a power supply system, which is connected to a collection system, a main control system, and a communication system and is integrated on a flexible PCB board.

7. The bolt loosening monitoring device according to claim 2, characterized in that: When in use, the flexible PCB board formed into a nut pattern is sleeved on the nut of the bolt, and the strong magnet is locked under the nut used with the bolt, and is threadedly connected with the stud of the bolt.

8. A bolt, characterized in that: By using the bolt loosening monitoring device described in any one of claims 1 to 6, a flexible PCB board formed in a nut pattern is sleeved on the nut of the bolt.

Images