Bolt looseness monitoring gasket and monitoring method

Abstract

The invention relates to a bolt looseness monitoring gasket and a bolt looseness monitoring method. The gasket comprises a gasket assembly (1), a triboelectric annular structure (2) and a connecting wire (3). The gasket assembly (1) comprises large gaskets (101) and small gaskets (102), the triboelectric annular structure (2) is arranged on the periphery of the small gaskets (102), and the large gaskets (101) are located on the two sides of the triboelectric annular structure (2) and the small gaskets (102); the triboelectric annular structure (2) comprises a positive electrode layer, a rubber dielectric layer and a negative electrode layer, and the connecting wire (3) is connected with the positive electrode layer and the negative electrode layer of the triboelectric annular structure (2) and used for transmitting signals of electrode surface potential difference. Compared with the prior art, the gasket is high in applicability and simple in structure, and a convenient and practical method is provided for health monitoring of bolt connecting components in engineering.

Description

Technical Field

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

[0002] Bolts are important connecting elements in construction, machinery, transportation and other projects. Their tightening quality directly affects the safety and reliability of the structure. With the acceleration of industrialization, bolts are used more and more widely, especially in high-load, high-vibration and harsh environments. Bolt loosening is a common and serious hidden danger. Therefore, online monitoring of bolt loosening is particularly important, which can achieve real-time early warning of bolt loosening and reduce equipment failures or safety accidents caused by loosening.

[0003] Traditional bolt loosening detection methods mainly rely on physical sensors such as strain gauges, vibration sensors or force sensors. These methods each have certain advantages and disadvantages, but they generally have some limitations:

[0004] Strain gauge monitoring method: The strain gauge determines the degree of looseness by measuring the deformation of the bolt, and usually requires the installation of a strain sensor on the bolt or connecting component. The disadvantage of this method is that the installation process is complicated, and the sensor is easily affected by environmental interference, such as temperature and humidity changes, resulting in unstable measurement. In addition, the electrical noise and transmission distance of the sensor itself will also affect the accuracy.

[0005] Vibration monitoring method: Vibration sensors are used to monitor the vibration signals generated by bolt loosening during the operation of the equipment. This method is often used to monitor large equipment, but the acquisition of vibration signals is greatly affected by factors such as equipment type and working environment, and it is impossible to immediately quantitatively analyze the specific degree of loosening. The vibration method can often only provide indirect information on loosening and cannot accurately reflect the slight loosening changes of bolts.

[0006] Force sensor monitoring method: Use force sensors to measure the force of bolted parts to determine whether the bolts are loose. However, this method requires the installation of force sensors at each bolt position, which increases cost and complexity. In addition, force sensors are sensitive to changes in the external environment (such as temperature, pressure, etc.) and are easily disturbed. Long-term use may lead to a decrease in measurement accuracy.

[0007] Visual inspection method: With the help of video monitoring and image processing technology, the looseness of the bolts is judged by observing the surface state of the bolts. This method is effective for surface looseness detection in simple scenarios, but it is difficult to respond to hidden locations or small looseness changes in a timely manner, and usually requires manual intervention, and cannot achieve real-time monitoring.

[0008] In summary, traditional bolt loosening monitoring methods have many disadvantages, such as complex installation, high cost, strong environmental interference, low accuracy, etc. These problems make it difficult for traditional monitoring methods to meet the needs of high accuracy, real-time performance and long-term stability, especially in some high-risk areas and harsh environments, where traditional technologies often cannot provide sufficient safety guarantees.

[0009] In order to overcome these shortcomings, passive sensing technology based on triboelectric effect has received widespread attention in recent years. The triboelectric effect can generate electric charge and form a potential difference when objects are in contact and in relative motion. This phenomenon has high sensitivity and accuracy in practical applications. Compared with traditional methods, triboelectric effect sensors have the advantages of no need for external power supply, high sensitivity, fast response speed, simple structure and low cost. Therefore, the intelligent bolt loosening monitoring system based on triboelectric effect has become a solution with great potential.

[0010] CN108775978A discloses a static prestress monitoring device and method based on PZT, which collects the voltage signal of the PZT smart gasket equivalent circuit through the lower computer module and transmits it to the upper computer for data analysis to realize the monitoring of static prestress, and calculates the prestress by using the corresponding relationship between the oscillation period of the signal and the static prestress. However, the smart gasket in CN108775978A involves pulse signal excitation. Since the working mechanism of the PZT sensor itself requires an external excitation signal, the system still needs power supply, which increases the complexity and power consumption of the system compared with the passive triboelectric sensor.

[0011] CN118462702A discloses a smart washer and method for monitoring bolt loosening based on a triboelectric origami superstructure. The smart washer includes a gasket, a spring and a triboelectric origami superstructure. When in use, the smart washer is installed between the bolt and the bolt connection component: if the bolt is not loose, the pre-tightening force of the bolt compresses the spring, and the triboelectric origami superstructure does not have deformation space at this time, and no electrical signal is output when the load acts on the bolt connection component; if the bolt is loose, the spring rebounds, and the triboelectric origami superstructure has deformation space at this time. The bolt connection component is displaced under the action of the load, causing the spring to be compressed again, driving the triboelectric origami superstructure to deform, causing friction between the triboelectric pairs and generating electrical signal output. After receiving the signal, the signal receiver can determine the degree of bolt loosening. However, the problem with the smart washer in CN118462702A in practical applications is that, on the one hand, the ordinary spring as the load-bearing body has insufficient bearing capacity, which makes it unable to withstand the bolt preload, and is very likely to undergo irreversible plastic deformation or even fracture; on the other hand, the smart washer system requires a larger deformable space to work properly, and in practical applications, when the space between the nut and the component is large enough, it often means that the nut has been completely separated from the washer, and the preload force of the bolt is close to zero, making the design ineffective in many practical scenarios.

[0012] Therefore, there is an urgent need for a smart gasket that can work passively and respond to small deformations. Summary of the invention

[0013] The object of the present invention is to provide a bolt loosening monitoring washer and a monitoring method, which can work passively and respond to small deformations.

[0014] The object of the present invention can be achieved by the following technical solutions: A bolt loosening monitoring washer comprises a washer assembly, a triboelectric annular structure and a connecting wire;

[0015] The gasket assembly comprises a large gasket and a small gasket, the triboelectric annular structure is arranged on the periphery of the small gasket, and the large gasket is located on both sides of the triboelectric annular structure and the small gasket;

[0016] The triboelectric annular structure comprises a positive electrode layer, a rubber dielectric layer and a negative electrode layer. The connecting wires are respectively connected to the positive electrode layer and the negative electrode layer of the triboelectric annular structure for transmitting signals of the potential difference on the electrode surfaces.

[0017] In the present invention, the rubber dielectric layer changes the electrode spacing through elastic rebound, thereby causing a change in the potential difference, which effectively reflects the degree of looseness of the bolt. If the bolt is not loose, the pre-tightening force of the bolt compresses the triboelectric annular structure, at which time the rubber dielectric layer in the triboelectric annular structure is compressed, the friction electrode spacing is reduced, and its surface induced charge density is relatively high, resulting in a large potential difference between the electrodes; if the bolt is loose, the triboelectric annular structure increases the electrode spacing due to the rebound effect of the rubber dielectric layer, thereby reducing the surface induced charge density and reducing the potential difference between the electrodes.

[0018] Preferably, the outer diameter of the small gasket does not exceed the inner diameter of the triboelectric annular structure.

[0019] Further preferably, the outer diameter of the small gasket is smaller than the inner diameter of the triboelectric annular structure.

[0020] Preferably, the inner diameters of the large gasket and the small gasket in the gasket assembly should match each other to ensure that the bolt can pass through the gasket assembly and be fixed to the bolt connection member.

[0021] Preferably, the large gasket and the small gasket in the gasket assembly are made of stainless steel.

[0022] Further preferably, the large gasket and the small gasket in the gasket assembly are made of 304 stainless steel.

[0023] Preferably, the positive electrode layer is composed of an insulating layer, a metal electrode layer and an electron-losing material layer stacked in sequence, and the negative electrode layer is composed of an electron-gaining material layer, a metal electrode layer and an insulating layer stacked in sequence, and the electron-losing material layer and the electron-gaining material layer are arranged facing each other.

[0024] Further preferably, the insulating layer is a polyimide film layer.

[0025] Further preferably, the metal electrode layer is an aluminum foil layer.

[0026] More preferably, the metal electrode layer is connected to a connecting wire.

[0027] Further preferably, the electron-losing material layer is a paper layer.

[0028] Further preferably, the electron-accepting material layer is a polytetrafluoroethylene film layer.

[0029] Further preferably, the layers of the positive electrode layer are bonded together by gluing.

[0030] Further preferably, the layers of the negative electrode layer are bonded together by gluing.

[0031] Further preferably, the rubber medium layer and the electron-losing material layer are bonded together by gluing.

[0032] Further preferably, the rubber medium layer and the electron-acquiring material layer are bonded together by gluing.

[0033] Further preferably, each of the positive electrode layer and the negative electrode layer is in a circular plate-like structure.

[0034] In the present invention, a high-strength adhesive bonding process is used between the layers to ensure that delamination or falling off will not occur during long-term use.

[0035] Preferably, the rubber medium layer comprises a rubber material and a cavity;

[0036] The rubber material is in a circular ring structure and is provided with a cavity.

[0037] In the present invention, the rubber material has high pressure resistance, wear resistance and anti-aging performance, and the surface can remain moist for a long time, ensuring the stability and monitoring accuracy of the gasket during long-term use.

[0038] Further preferably, the rubber material is provided with a plurality of cavities at intervals along the circumferential direction, and the cavities penetrate the rubber material along the axial direction.

[0039] More preferably, the positive electrode layer and / or the negative electrode layer is provided with a protruding structure on a side facing the rubber medium layer.

[0040] Preferably, the protruding structure corresponds to the position of the cavity.

[0041] Preferably, the total thickness of the protruding structure does not exceed the thickness of the rubber material in a normal state.

[0042] Preferably, the connecting wire is connected to a signal receiving component.

[0043] Further preferably, the signal receiving component includes a digital multimeter, and the potential difference between the positive and negative electrodes can be effectively transmitted to the digital multimeter.

[0044] More preferably, the digital multimeter is connected to a host computer, and the host computer is used to receive and analyze voltage signals, thereby achieving high-precision monitoring of bolt loosening.

[0045] In the present invention, the potential difference change can be monitored in real time by a digital multimeter, thereby determining the degree of looseness of the bolt. According to the change amplitude of the potential difference, the looseness of the bolt can be accurately assessed, and a corresponding early warning signal can be provided.

[0046] A bolt loosening monitoring method is performed using the bolt loosening monitoring washer, comprising the following steps:

[0047] The bolt loosening monitoring washer is installed between the bolt and the bolt connection member, and the positive electrode layer and the negative electrode layer of the triboelectric annular structure are connected to the signal receiving component through connecting wires respectively;

[0048] When the bolt is loosened, the triboelectric annular structure generates a potential difference during deformation, and the potential difference is transmitted to the signal receiving component via the connecting wire.

[0049] Preferably, the bolt loosening monitoring method specifically comprises the following steps:

[0050] (a) installing the bolt loosening monitoring washer between the bolt and the bolt connection component;

[0051] (b) connecting the positive electrode layer and the negative electrode layer of the triboelectric ring structure to a digital multimeter via connecting wires, and connecting the digital multimeter to a host computer;

[0052] (c) When the bolt is loose, the triboelectric annular structure generates a potential difference due to the accumulation of induced charge during the deformation process. The potential difference is transmitted to the digital multimeter and received and analyzed by the host computer, which then issues an alarm and displays the degree of looseness, thereby achieving high-precision monitoring of bolt loosening;

[0053] (d) The alarm signals and loose data obtained by the host computer analysis are transmitted to the cloud platform through the wireless transmission module, thereby realizing remote monitoring and multi-point monitoring, and improving the coverage and real-time performance of monitoring.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] 1. The gasket of the present invention can work passively and can respond to small deformations.

[0056] 2. Compared with the intelligent gasket for monitoring bolt loosening based on the triboelectric origami superstructure, the present invention can generate a change in potential difference within a tiny deformation space (i.e., a tiny displacement after the bolt is loosened) and can respond to tiny deformations.

[0057] 3. The present invention realizes real-time monitoring of bolt loosening through a simple device and does not require an external power supply.

[0058] 4. The triboelectric annular structure of the present invention can produce a change in potential difference within a very small deformation space (i.e., a small displacement after the bolt is loosened) through the coordinated work of the triboelectric annular structure and a small gasket. Traditional bolt loosening monitoring systems require a larger deformation space to correctly respond to bolt loosening, but at this time the preload force of the bolt has often been significantly reduced or even zero, which makes it difficult for traditional monitoring systems to accurately monitor the loosening state in the early stages. In contrast, the present invention adopts the principle of triboelectric effect, and can accurately monitor the loosening of the bolt even in the case of a small loss of preload force, avoiding the defect that traditional systems cannot work effectively when there is insufficient space or a decrease in preload force, and has better adaptability in a wider range of application scenarios.

[0059] 5. The present invention takes into account the limitations of existing bolt loosening monitoring technology, which usually relies on external excitation signals and power supply to maintain the working state of the sensor, and proposes an intelligent gasket and method for bolt loosening monitoring based on the triboelectric effect. The bolt loosening monitoring system derived from the present invention does not require an external power supply and excitation signal. The triboelectric effect can generate electric charges through physical contact and friction processes. The change in preload force affects the distribution of induced charges on the electrode surface, which in turn leads to a change in the potential difference, thereby achieving accurate monitoring of the loose state of the bolt. This design greatly simplifies the system structure, making it suitable for some applications where it is difficult to provide continuous power supply, such as special environments such as offshore platforms and high-pressure vessels. Through this innovative design, the energy efficiency of the system has been greatly improved, while also reducing the cost and complexity in long-term use.

[0060] 6. The present invention establishes a quantitative relationship between the degree of bolt loosening and the potential difference through the design of a triboelectric annular structure, can accurately capture the potential difference change between the electrodes during the bolt loosening process, and connects to the host computer through a digital multimeter, transmits these signals and further processes and analyzes them, thereby achieving high-precision monitoring of the bolt loosening state. Especially in the early stage of bolt loosening, even if there is a very small displacement change, the monitoring system of the present invention can react quickly, issue an alarm in time and display the specific degree of loosening. Through this high-precision monitoring and instant alarm function, the present invention can effectively improve the safety of the equipment, ensure that measures are taken in time when the bolt loosening does not reach a dangerous level, and avoid accidents. At the same time, this accurate monitoring method also provides more efficient decision-making support for the maintenance and management of equipment, especially in large-scale industrial equipment and important engineering structures, and has very important application value.

[0061] 7. The gasket of the present invention has strong applicability and simple structure, and provides a convenient and practical method for health monitoring of bolted connection components in engineering.

[0062] 8. The present invention integrates triboelectric effect sensing technology, which can be used to monitor the looseness of bolted connections with high precision, and is widely used in online detection and fault warning of bolted connections in the fields of industry, machinery, construction, etc.

[0063] 9. The triboelectric annular structure of the present invention is based on the triboelectric effect, requires low cost of raw materials, has a wide range of choices, and is simple to prepare. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a structural schematic diagram of a bolt loosening monitoring washer of the present invention;

[0065] Figure 2 This is a schematic diagram of a triboelectric annular structure explosion structure of the present invention;

[0066] Figure 3 This is a schematic diagram of the working principle of a cross-section of a triboelectric annular structure of the present invention;

[0067] Figure 4 is a schematic diagram of a bolt loosening monitoring system based on washers of the present invention;

[0068] Figure 5 It is another schematic diagram of the explosion structure of the triboelectric annular structure of the present invention;

[0069] Figure 6 It is a schematic diagram of the working principle of another cross-section of a triboelectric annular structure of the present invention;

[0070] In the figure: 1. gasket assembly; 2. triboelectric ring structure; 3. connecting wire; 4. digital multimeter; 5. host computer; 6. wireless transmission module; 7. cloud platform; 101. large gasket; 102. small gasket; 201. polyimide film layer; 202. aluminum foil layer; 203. paper layer; 204. polytetrafluoroethylene film layer; 205. rubber material; 206. cavity. DETAILED DESCRIPTION

[0071] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0072] Example 1

[0073] A bolt loosening monitoring washer, such as Figure 1 As shown, it includes a gasket assembly 1, a triboelectric annular structure 2 and a connecting wire 3.

[0074] The gasket assembly 1 consists of two large gaskets 101 and a small gasket 102. The large gasket 101 is located on both sides of the triboelectric annular structure 2 and the small gasket 102. The three are axially stacked to form a "large gasket-(triboelectric annular structure + small gasket)-large gasket" layered structure. The triboelectric annular structure 2 is arranged on the periphery of the small gasket 102.

[0075] Furthermore, the triboelectric annular structure 2 includes a positive electrode layer, a rubber dielectric layer and a negative electrode layer arranged in sequence, and the connecting wire 3 is respectively connected to the positive electrode layer and the negative electrode layer of the triboelectric annular structure 2 for transmitting the signal of the electrode surface potential difference.

[0076] Example 2

[0077] A bolt loosening monitoring gasket, wherein the positive electrode layer is composed of an insulating layer, a metal electrode layer and an electron-losing material layer stacked in sequence, and the negative electrode layer is composed of an electron-gaining material layer, a metal electrode layer and an insulating layer stacked in sequence.

[0078] In this embodiment, Figure 2 As shown, the insulating layer is a polyimide film layer 201, the metal electrode layer is an aluminum foil layer 202, the electron-losing material layer is a paper layer 203, and the electron-gaining material layer is a polytetrafluoroethylene film layer 204. The rubber dielectric layer includes a rubber material 205 and a cavity 206 disposed on the rubber material. The rest is the same as in Example 1.

[0079] Example 3

[0080] A smart washer for monitoring bolt loosening based on triboelectric effect, comprising a washer assembly 1, a triboelectric annular structure 2 and a connecting wire 3.

[0081] The gasket assembly 1 is composed of two large gaskets 101 and one small gasket 102, which together constitute the load body of the smart gasket. The large gasket 101 is located on both sides of the triboelectric annular structure 2 and the small gasket 102. The three are axially superimposed to form a "large gasket-(triboelectric annular structure + small gasket)-large gasket" layered structure. The triboelectric annular structure 2 is arranged on the periphery of the small gasket 102 as the functional body of the smart gasket. The triboelectric annular structure 2 includes a positive electrode layer, a rubber dielectric layer and a negative electrode layer. The connecting wire 3 is respectively connected to the positive electrode layer and the negative electrode layer of the triboelectric annular structure 2 through aluminum foil tape, which is used to transmit the signal of the electrode surface potential difference.

[0082] The triboelectric annular structure 2 and the small gasket 102 together form a structural system similar to a parallel spring, wherein the triboelectric annular structure 2 acts as a soft spring to bear a small pressure, and the small gasket 102 acts as a hard spring to bear the main preload. When the bolt is tightened, the small gasket 102 bears almost all of the preload, while the triboelectric annular structure 2 maintains an elastic state and responds sensitively to the small deformation caused by the loosening of the bolt.

[0083] by Figure 3 The working principle of the triboelectric annular superstructure is explained as an example. When the bolts are not loose, the pre-tightening force of the bolts keeps the triboelectric annular structure 2 in a compressed state; when the bolts are loose, the pre-tightening force of the bolts decreases, causing the triboelectric annular structure 2 to rebound.

[0084] The triboelectric annular structure 2 includes a positive electrode layer, a rubber dielectric layer, and a negative electrode layer arranged in sequence from top to bottom, and the electrode spacing and surface charge density change with the degree of bolt loosening. The positive electrode layer is composed of an insulating layer, a metal electrode layer, and an electron-losing material layer stacked in sequence; the negative electrode layer is composed of an electron-gaining material layer, a metal electrode layer, and an insulating layer stacked in sequence. Among them, the insulating layer is a polyimide film layer 201, the metal electrode layer is an aluminum foil layer 202, the electron-losing material layer is a paper layer 203, and the electron-gaining material layer is a polytetrafluoroethylene film layer 204. The rubber dielectric layer includes a rubber material 205 and a cavity 206. During the loosening of the bolt, the rubber material 205 not only acts as an elastomer to respond to the applied pressure, but also acts as a dielectric material together with its internal cavity, significantly improving the efficiency of charge accumulation and separation.

[0085] The bonding process between the layers of the triboelectric annular structure 2 uses high-strength adhesive. In this embodiment, acrylic pressure-sensitive adhesive is used to ensure that there will be no delamination or peeling during long-term use. The aluminum foil layer 202 and the paper layer 203 are bonded along the edges of the aluminum foil layer 202 and the paper layer 203, and the aluminum foil layer 202 and the polytetrafluoroethylene film layer 204 are bonded along the edges of the aluminum foil layer 202 and the polytetrafluoroethylene film layer 204 to achieve charge transfer; the polyimide film layer 201 and the aluminum foil layer 202 are bonded to each other; the paper layer 203 and the rubber material 205 are bonded to each other; the polytetrafluoroethylene film layer 204 and the rubber material 205 are bonded to each other.

[0086] In this embodiment, the paper layer 203 and the polytetrafluoroethylene film layer 204 are firstly frictionally charged with opposite signs, and then respectively installed on both sides of the rubber material 205. When the bolts are not loosened, the rubber dielectric layer in the triboelectric annular structure 2 is compressed under the bolt preload, causing the friction electrodes to approach and maintain a high charge density, thereby generating a large potential difference between the electrodes; when the bolts are loosened, the rubber dielectric layer in the triboelectric annular structure 2 rebounds and drives the friction electrodes to separate, the charge density decreases, and the potential difference between the electrodes decreases as the compression of the rubber dielectric layer decreases.

[0087] by Figure 4The working principle of the bolt loosening monitoring system based on the smart washer is explained as an example. The bolt loosening monitoring system based on the smart washer also includes a digital multimeter 4, a host computer 5, a wireless transmission module 6, and a cloud platform 7. The two layers of aluminum foil 202 of the triboelectric ring structure 2 are connected to the digital multimeter 4 by connecting wires 3 to ensure that the potential difference of the positive and negative electrodes can be effectively transmitted to the digital multimeter 4. The digital multimeter 4 is connected to the host computer 5 to complete the reception and analysis of the potential difference signal. Specifically, a signal analysis and processing program is installed in the host computer 5. First, the characteristic parameters related to the loosening of the bolt are extracted by analyzing the timing and amplitude of the signal. For example, the fluctuation range, change trend and frequency characteristics of the potential difference are analyzed to determine the specific situation of the loosening of the bolt. Secondly, an artificial intelligence algorithm (such as a support vector machine, a neural network, a random forest, etc.) is used to train and test according to the characteristic information to measure the loss of the bolt preload force and realize the monitoring of the degree of loosening of the bolt. In this embodiment, a neural network is used as an example for explanation: first, the data is labeled according to the collected potential difference signal, and the label can be labeled based on different bolt loosening states (for example, 90 / 70 / 50 / 30 / 10% of the initial preload); secondly, the data set is divided into a training set and a test set. Usually, 80% to 90% of the data is used to train the model, and the remaining 10% to 20% is used to verify and test the performance of the model. The training set is used for the learning process of the algorithm, and the test set is used to evaluate the actual effect of the model; then the model parameters are initialized, including the number of network layers, the number of neurons in each layer, the learning rate, etc.; then a suitable loss function is selected to optimize the performance of the model. The mean square error (MSE) is often used in the problem of bolt loosening monitoring; then based on the training set data, the model parameters are adjusted using an optimization algorithm (such as the gradient descent method) to minimize the loss function value. In this process, the algorithm adjusts the parameters of the model through continuous iterations to better fit the training data; finally, the adjusted model is verified using the test set to evaluate its generalization ability on unseen data. By comparing the error between the predicted value and the actual value, the model's accuracy, precision, recall and other indicators are calculated. If the verification results show that the model performs poorly, you can further adjust the hyperparameters, optimize the algorithm or improve the model architecture.

[0088] In order to achieve remote monitoring and intelligent decision support, all processed and analyzed data will be transmitted to the cloud platform 7 through the wireless transmission module 6. On the cloud platform, the data will be stored for a long time and further analyzed. Through the cloud server, the system can realize centralized management and analysis of data from multiple monitoring points.

[0089] Based on the computing power of the cloud platform, the system can monitor a large number of devices in real time, analyze data trends, generate reports, and provide predictive maintenance recommendations. The cloud platform can also perform remote diagnosis of the equipment and automatically issue early warning notifications based on the prediction of bolt loosening to help operation and maintenance personnel take timely measures. Once the bolt loosening reaches the preset threshold, the system will automatically trigger an alarm signal and send it to the host computer 5 or related terminals through the wireless transmission module 6. Operation and maintenance personnel can monitor in real time through mobile devices, PCs, etc. to ensure that they can quickly respond to potential equipment safety risks.

[0090] Furthermore, the smart washer is designed to be universal and can be customized according to different bolt specifications and usage scenarios to meet the needs of different users.

[0091] Example 4

[0092] A smart washer for monitoring bolt loosening based on triboelectric effect, such as Figures 5-6 As shown, the paper layer 203 is provided with a protruding structure of the same material on the side facing the rubber medium layer, and the polytetrafluoroethylene film layer 204 is provided with a protruding structure of the same material on the side facing the rubber medium layer, and the protruding structures of the paper layer 203 and the polytetrafluoroethylene film layer 204 correspond to the positions of the cavity 206. The rest is the same as in Example 3.

[0093] When the raised structures of the paper layer 203 and the raised structures of the polytetrafluoroethylene film layer 204 are in contact with each other, they generate surface charges of opposite signs on the contact surfaces. This embodiment also eliminates the need to frictionally charge the paper layer 203 and the polytetrafluoroethylene film layer 204 with opposite signs before installation, making the operation simpler.

[0094] The triboelectric annular structure of the present invention induces charge changes through the triboelectric effect, thereby reflecting the degree of bolt loosening. During use, the smart gasket is installed between the bolt and the bolt connection component. If the bolt is not loose, the pre-tightening force of the bolt compresses the triboelectric annular structure. At this time, the rubber dielectric layer in the triboelectric annular structure is compressed, the distance between the friction electrodes is reduced, and the surface induced charge density is relatively high, resulting in a large potential difference between the electrodes; if the bolt is loose, the triboelectric annular structure increases the electrode distance due to the rebound effect of the rubber dielectric layer, thereby reducing the surface induced charge density and reducing the potential difference between the electrodes. The change in potential difference can be monitored in real time by a digital multimeter to determine the degree of looseness of the bolt. According to the amplitude of the change in the potential difference, the looseness of the bolt can be accurately assessed and a corresponding early warning signal can be provided.

[0095] In order to overcome the limitations of many existing bolt loosening monitoring methods, namely, the need for external excitation signals and power supply, insufficient load-bearing capacity of the load body and the need for a large deformation space to work properly, the present invention provides a bolt loosening monitoring smart gasket and method based on the triboelectric effect. The smart gasket uses a uniquely designed triboelectric annular structure so that the potential difference between the positive and negative electrodes changes with the change in the degree of bolt loosening. The potential difference signal is transmitted to the host computer through a digital multimeter for real-time analysis, thereby achieving high-precision monitoring of the bolt loosening state. The system can issue an alarm in a timely and accurate manner and display the specific degree of loosening, significantly improving the accuracy and reliability of bolt loosening monitoring.

[0096] It should be noted that the directions or positional relationships indicated by "front", "back", "left", "right", "up", "down", "inside", "outside" and the like described in this application are based on the directions or positional relationships indicated in the accompanying drawings, and are intended to be more concise and clear when describing this application. They do not mean that the devices or components must have certain direction restrictions, and therefore cannot be used as limitations on this application. In addition, the embodiments described in this application are only part of the embodiments of the present invention and cannot represent all embodiments. Other embodiments obtained by those skilled in the art without making creative efforts on this application should all fall within the protection scope of the present invention.

[0097] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0098] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0099] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A bolt loosening monitoring washer, characterized in that: It comprises a gasket assembly (1), a triboelectric annular structure (2) and a connecting wire (3); The gasket assembly (1) comprises a large gasket (101) and a small gasket (102); the triboelectric annular structure (2) is arranged on the periphery of the small gasket (102); and the large gasket (101) is located on both sides of the triboelectric annular structure (2) and the small gasket (102); The triboelectric annular structure (2) comprises a positive electrode layer, a rubber dielectric layer and a negative electrode layer, and the connecting wire (3) is respectively connected to the positive electrode layer and the negative electrode layer of the triboelectric annular structure (2) for transmitting a signal of an electrode surface potential difference.

2. The bolt loosening monitoring washer according to claim 1, characterized in that: The inner diameters of the large gasket (101) and the small gasket (102) in the gasket assembly (1) match each other, and bolts can pass through the gasket assembly (1) and be fixed to the bolt connection component.

3. The bolt loosening monitoring washer according to claim 1, characterized in that: The positive electrode layer is composed of an insulating layer, a metal electrode layer and an electron-losing material layer stacked in sequence, and the negative electrode layer is composed of an electron-gaining material layer, a metal electrode layer and an insulating layer stacked in sequence, and the electron-losing material layer and the electron-gaining material layer are arranged facing each other.

4. The bolt loosening monitoring washer according to claim 3, characterized in that: The insulating layer is a polyimide film layer (201); The metal electrode layer is an aluminum foil layer (202); The electron-losing material layer is a paper layer (203); The electron-acquiring material layer is a polytetrafluoroethylene film layer (204).

5. The bolt loosening monitoring washer according to claim 3, characterized in that: The layers of the positive electrode layer are bonded to each other by adhesive bonding, the layers of the negative electrode layer are bonded to each other by adhesive bonding, and the rubber medium layer is bonded to the electron-losing material layer and the electron-gaining material layer by adhesive bonding.

6. The bolt loosening monitoring washer according to claim 1, characterized in that: The rubber medium layer comprises a rubber material (205) and a cavity (206); The rubber material (205) is in a circular ring structure and is provided with a cavity (206).

7. The bolt loosening monitoring washer according to claim 6, characterized in that: The rubber material (205) is provided with a plurality of cavities (206) at intervals along the circumferential direction, and the cavities (206) penetrate the rubber material (205) along the axial direction.

8. The bolt loosening monitoring washer according to claim 7, characterized in that: The positive electrode layer and / or the negative electrode layer is provided with a protruding structure on the side facing the rubber medium layer, and the protruding structure corresponds to the position of the cavity (206).

9. The bolt loosening monitoring washer according to claim 8, characterized in that: The total thickness of the protruding structure does not exceed the thickness of the rubber material (205) in a normal state.

10. A method for monitoring bolt loosening, characterized in that: The method is carried out using the bolt loosening monitoring washer according to any one of claims 1 to 9, comprising the following steps: The bolt loosening monitoring washer is installed between the bolt and the bolt connection component, and the positive electrode layer and the negative electrode layer of the triboelectric annular structure (2) are respectively connected to the signal receiving component via connecting wires (3); When the bolt is loosened, the triboelectric annular structure (2) generates an electric potential difference during deformation, and the electric potential difference is transmitted to the signal receiving component via the connecting wire (3).

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