An embedded fastener for self-powered intelligent sensing nodes for equipment condition monitoring

Abstract

The application relates to the technical field of industrial equipment state monitoring, micro intelligent sensing and vibration energy collection, and discloses a self-powered intelligent sensing node embedded in a fastener for equipment state monitoring, which comprises a fastener body, a piezoelectric energy extraction unit, an energy management and storage unit, a micro circuit board, a three-axis MEMS sensing unit, an MCU processing unit and a wireless communication unit; through limit miniaturization integration, the application is adapted to the narrow embedded space, the core adopts a high-density full-function micro PCB with an outer diameter of less than or equal to 12 mm, all function circuits are integrated in the extremely small space, the application can be completely embedded into the closed cavity of the fastener, is free of exposure and does not occupy the external space of equipment, has the dual functions of standard fastener load bearing connection and intelligent sensing monitoring, and can cover all kinds of electromechanical equipment scenes by virtue of the general attribute of the fastener.

Description

Technical Field

[0001] This invention relates to the fields of industrial equipment condition monitoring, micro-intelligent sensing and vibration energy harvesting technology, and more specifically to a self-powered intelligent sensing node embedded in a fastener for equipment condition monitoring. Background Technology

[0002] During the long-term operation of various rotating machinery and transmission equipment, abnormal vibration and excessive temperature are the two most critical characteristic parameters of equipment wear, fatigue failure, and downtime. Therefore, online equipment condition monitoring is a key foundation for industrial predictive maintenance. Current conventional monitoring solutions in the industry have several significant shortcomings. First, traditional vibration and temperature sensors are mostly external, independent structures with a large overall size. They require dedicated brackets, magnetic bases, or on-site drilling for fixation, which not only occupies external space but also requires modification of the original equipment casing, compromising the integrity of the equipment. This is especially true in compact rotating transmission parts such as rotating shafts, couplings, gearbox end faces, and bearing housing connections, where conventional external sensors simply lack installation space, making it impossible to deploy monitoring points. Second, existing monitoring solutions are all retrofitted to the equipment and cannot be integrated with the factory design of electromechanical equipment such as reducers, gearboxes, and motors. On-site installation is cumbersome, has poor compatibility, and is difficult to standardize and mass-produce. Third, existing monitoring sensors generally use wired power supply or disposable lithium battery power supply. Wired power supply is cumbersome with wiring and the lines are prone to aging and damage, while battery power supply requires periodic manual intervention. Disassembly and replacement of equipment is labor-intensive and requires extensive periodic maintenance, making it impractical for large-scale deployments. Furthermore, traditional sensors have fragmented functions, with highly separated acquisition, processing, and transmission modules, resulting in low overall integration, high static power consumption, and bulky circuitry that cannot fit into confined installation spaces. Additionally, traditional sensors only collect and upload raw time-domain vibration data, lacking edge preprocessing capabilities such as data noise reduction, FFT spectrum analysis, and feature extraction. The massive volume of raw data and high wireless transmission power consumption significantly increase the processing pressure on edge gateways and backend cloud platforms. Faults in gearboxes, transmission systems, and other equipment are often concentrated at fastening stress points such as bolts, locating pins, pin shafts, and connectors. Existing technologies cannot deploy monitoring at these core fastener locations, requiring remote indirect monitoring of the entire device, leading to low monitoring accuracy and delayed fault tracing. External installations are also prone to signal attenuation and interference distortion. In summary, the industry urgently needs a miniature intelligent sensing node that can be embedded inside various fasteners, overcomes the challenges of miniaturized integration in extreme spaces, does not damage the device's structure, can be pre-installed with the device at the factory, is self-powered by vibration, has low-power wireless transmission, and has front-end edge data preprocessing capabilities. Summary of the Invention

[0003] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a self-powered intelligent sensing node embedded in a fastener for equipment status monitoring, so as to solve the technical problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a self-powered intelligent sensing node embedded in a fastener for equipment status monitoring, comprising a fastener body, a piezoelectric energy harvesting unit, an energy management and storage unit, a microcircuit board, a triaxial MEMS sensing unit, an MCU processing unit, and a wireless communication unit; the fastener body has a sealed cavity, the piezoelectric energy harvesting unit is disposed inside the sealed cavity, and the piezoelectric energy harvesting unit converts the mechanical energy of equipment vibration into electrical energy; the energy management and storage unit is electrically connected to the piezoelectric energy harvesting unit, and the energy management and storage unit is used for rectification, voltage regulation, and energy storage; the microcircuit board is fixedly mounted... The device is fixedly installed within the sealed cavity. The micro-circuit board is a high-density, fully integrated micro-PCB structure with an outer diameter of no more than 12mm. The micro-circuit board integrates all functional circuits for power management, sensor acquisition, main control calculation, and wireless communication. The triaxial MEMS sensing unit is integrated on the micro-circuit board and is used to acquire triaxial vibration and temperature signals. The MCU processing unit is integrated on the micro-circuit board, and the wireless communication unit is integrated on the micro-circuit board. The MCU processing unit is electrically connected to the triaxial MEMS sensing unit, the wireless communication unit, and the energy management and storage unit, respectively.

[0005] In a preferred embodiment, a cavity top cover is provided at the top of the sealed cavity of the fastener body. The fastener body has the dual functions of mechanical fastening connection of the equipment and in-situ working condition monitoring of the sensing node. The sensing unit is rigidly integrated and fitted with the fastener to collect the original pure working condition data of the key stress points of the equipment.

[0006] In a preferred embodiment, the fastener body includes any one or more of the following: bolt, stud, locating pin, pin shaft, flat key, spline, lock nut, retaining ring, expansion sleeve, rivet, and anchor bolt.

[0007] In a preferred embodiment, the microcircuit board is a circular high-density precision PCB with a maximum outer diameter of less than 12 mm.

[0008] In a preferred embodiment, the piezoelectric energy harvesting unit is a piezoelectric ceramic cantilever beam energy harvesting structure.

[0009] In a preferred embodiment, the energy management storage unit includes a rectifier circuit, a DC-DC voltage regulator circuit, and a supercapacitor energy storage module.

[0010] In a preferred embodiment, the wireless communication unit is a LoRa low-power wireless communication module.

[0011] In a preferred embodiment, the MCU processing unit is configured to perform front-end preprocessing operations such as data filtering, FFT spectrum transformation, and vibration feature extraction.

[0012] In a preferred embodiment, the overall structure can be pre-assembled as an integrated unit when the industrial equipment leaves the factory.

[0013] In a preferred embodiment, the sealed cavity is filled with epoxy potting compound to completely encapsulate all internal components. After the potting compound cures, it forms an integral sealed structure that fits tightly against the inner wall of the cavity. This integral sealed structure provides vibration buffering and heat conduction pathways.

[0014] The technical effects and advantages of this invention are as follows: 1. This invention achieves extreme miniaturization integration, adapting to embedded narrow spaces. The core adopts a high-density full-function micro PCB with an outer diameter of ≤12mm, integrating all functional circuits in an extremely small space. It can be completely embedded into the sealed cavity of the fastener, with no exposure and without occupying external space of the equipment. It has both standard fastener load-bearing connection and intelligent sensing and monitoring functions. Relying on the universal attributes of fasteners, it can cover all categories of electromechanical equipment scenarios. 2. This invention can be directly embedded inside various fasteners and installed synchronously with the standard equipment assembly. No drilling or external brackets are required, and the original structure of the equipment is not damaged. It utilizes the mechanical energy of equipment vibration to extract energy and is combined with supercapacitor energy storage, eliminating the need for wired power supply and traditional battery power supply. The maintenance cost is extremely low for large-scale deployment. 3. This invention achieves rigid bonding between the sensing unit and the device, eliminating signal transmission loss and accurately reproducing early minor fault characteristics of the device. The built-in MCU can perform filtering, FFT transformation, and feature extraction, significantly reducing wireless transmission power consumption and backend platform computing pressure. 4. This invention adopts LoRa low-power communication, which has a long transmission distance and strong resistance to interference in industrial and mining sites. This invention can be pre-installed in the integrated design of the whole equipment and is suitable for industrial mass production. Attached Figure Description

[0015] Figure 1 This is a schematic cross-sectional view of the overall structure of the present invention.

[0016] Figure 2 This is a schematic diagram of the circuit hardware framework connection frame of the present invention.

[0017] The attached figures are labeled as follows: 1. Fastener body; 2. Cavity top cover; 3. Piezoelectric energy harvesting unit; 4. Micro circuit board; 5. Energy management and storage unit. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The self-powered intelligent sensing node embedded in a fastener for device status monitoring involved in the present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Reference Figure 1 and Figure 2 The present invention provides a self-powered intelligent sensing node embedded in a fastener for device status monitoring, including a fastener body 1, a piezoelectric energy harvesting unit 3, an energy management and storage unit 5, a micro circuit board 4, a triaxial MEMS sensing unit, an MCU processing unit, and a wireless communication unit.

[0020] In this embodiment, the piezoelectric energy harvesting, energy management, ≤12mm miniature full-function PCB, triaxial MEMS sensing, MCU and wireless communication unit are all embedded in the sealed cavity of the fastener, so that the fastener has both mechanical fastening and working condition monitoring functions. This enables in-situ, clean data acquisition of key stress points of the equipment, without the need for external power supply and wiring. The overall structure is compact and easy to install.

[0021] Reference Figure 1 The fastener body 1 has a sealed cavity inside. The fastener is a broad type of fastening connector, including but not limited to: bolts, studs, locating pins, pins, flat keys, splines, anti-loosening self-locking nuts, shaft retaining rings, expansion sleeves, rivets, equipment anchor bolts, and housing locating pins. The fastener is installed synchronously with the industrial equipment assembly without additional modification to the equipment structure. The sensing node is adapted to various general fasteners such as bolts, studs, pins, keys, and rivets, expanding the application coverage of the product. It can be standardized and mass-produced for various electromechanical equipment without changing the original fastening scheme of the equipment.

[0022] Reference Figure 2 The piezoelectric energy harvesting unit 3 is arranged in a sealed cavity inside the fastener and adopts a piezoelectric ceramic cantilever beam structure. Relying on the piezoelectric effect generated by the operation of the equipment and the vibration deformation of the fastener, the mechanical energy of the environmental vibration is converted into electrical energy, which serves as the power source for the entire sensing node. By utilizing the piezoelectric ceramic cantilever beam structure, deformation and charge output are efficiently generated under the excitation of equipment vibration, realizing the conversion of vibration mechanical energy into electrical energy, and providing a sustainable and maintenance-free self-powered source for the entire node.

[0023] Reference Figure 2The energy management unit is electrically connected to the piezoelectric energy harvesting unit 3, and integrates a rectifier circuit, a voltage regulator circuit, a DC-DC conversion circuit and a supercapacitor energy storage module. Its function is to rectify, regulate and store the unstable AC power generated by piezoelectric energy harvesting, and convert intermittent electrical energy into a stable and continuous working voltage to meet the low power consumption power supply requirements of the whole machine. When the vibration is weak, it relies on the discharge of the supercapacitor to maintain operation.

[0024] Reference Figure 2 The micro circuit board 4 is a circular high-density precision micro PCB board with an outer diameter of no more than 12mm. It is fixedly installed in the sealed cavity inside the fastener. In the extremely narrow space, the chip units for power management, sensing and acquisition, main control and computing, and wireless communication are integrated. By using a circular high-density PCB with an outer diameter of ≤12mm, all functional circuits are integrated in the extremely narrow space. This overcomes the problem of miniaturization layout of the cavity inside the fastener and ensures that the node can be embedded and installed without affecting the original mechanical properties of the fastener.

[0025] Reference Figure 2 The triaxial MEMS sensing unit is soldered onto the micro circuit board 4, which can synchronously and in real time collect the X / Y / Z triaxial vibration amplitude, vibration frequency and ambient operating temperature parameters during the operation of the equipment.

[0026] Reference Figure 2 The MCU processing unit is a low-power microcontroller chip that is electrically connected to the triaxial MEMS sensing unit, energy management unit, and wireless communication unit. The MCU processing unit is responsible for front-end edge preprocessing work such as timed wake-up, periodic data acquisition, signal filtering and noise reduction, FFT time-domain to frequency-domain transformation, and vibration feature parameter extraction, thereby reducing the amount of raw data transmission.

[0027] Reference Figure 2 The wireless communication unit is a low-power long-range wireless transmission module, preferably using the LoRa communication standard, but also compatible with BLE Bluetooth, NB-IoT, and ZigBee. The wireless communication unit wirelessly transmits the effective operating condition data preprocessed by the MCU processing unit to an external edge computing gateway, field host computer, or cloud monitoring platform. It adopts LoRa low-power long-range wireless communication, taking into account both the overall power consumption control of the node and the reliable transmission capability in the complex electromagnetic environment of the industrial site. No additional wiring is required, and it supports monitoring of large-area equipment groups.

[0028] Reference Figure 1 and Figure 2The overall structure can be pre-assembled as an integrated unit when the industrial equipment is shipped. The fastener body 1 has the dual functions of mechanical fastening connection of the equipment and in-situ working condition monitoring of the sensing node. The sensing unit is rigidly integrated with the fastener to collect the original pure working condition data of the key stress points of the equipment. The sealed cavity is filled with epoxy potting compound to completely wrap all internal components. After the potting compound is cured, it forms an overall sealed structure that is tightly attached to the inner wall of the cavity. This overall sealed structure provides vibration buffering and heat conduction pathways.

[0029] In this embodiment, a zero-loss vibration transmission path is formed through the rigid surface without gap between the fastener body 1 and the equipment body, and between the sensing unit and the inner wall of the fastener. The collected signal is pure, interference-free, and attenuated, truly reflecting the early minor fault characteristics of the equipment, significantly improving monitoring sensitivity and fault tracing accuracy. Epoxy potting compound or silicone gel is used to completely wrap all components in the cavity, forming a sealed structure with an IP67 or higher protection level. At the same time, vibration buffering and heat dissipation pathways are provided, enabling the node to work stably for a long time in harsh industrial environments such as underground, dusty, humid, and oily environments.

[0030] Example 2 This embodiment provides a wireless self-powered intelligent sensor node for monitoring the condition of industrial equipment, which is embedded inside a fastener and is integrated into the head of a standard hexagonal head bolt.

[0031] The bolt head has a cylindrical sealed cavity inside, with a height of about 7mm and a diameter of about 12mm. The inner wall can be provided with a threaded structure for positioning or sealing. The cavity is completely potted with epoxy potting compound to achieve a waterproof, dustproof and vibration-proof sealing effect. At the bottom of the cavity, a piezoelectric energy harvesting unit is fixedly installed. The piezoelectric energy harvesting unit adopts a piezoelectric ceramic cantilever beam structure. The free end of the cantilever beam can bend and deform when the bolt vibrates with the equipment, thereby generating charge output based on the positive piezoelectric effect. The micro circuit board is a circular high-density precision PCB board with a diameter of 12mm and a thickness of about 1.3mm. It is fixedly installed in the cavity above the piezoelectric energy harvesting unit. The micro circuit board integrates the following components through surface mount technology: a triaxial MEMS sensing unit, an MCU processing unit (using an ultra-low power ARM Cortex-M0+ core chip), a wireless communication unit (LoRa module, operating in the 433MHz or 868 / 915MHz frequency band), and some peripheral circuits of the energy management storage unit (5). Through optimized layout wiring and ground isolation design, the signal crosstalk and electromagnetic compatibility problems in the extreme space are solved. The energy management and energy storage unit includes: a rectifier bridge connected to the output of the piezoelectric energy harvesting unit, a DC-DC boost / regulator chip (LTC3588-1), and a large-capacity supercapacitor. The supercapacitor is also encapsulated in the remaining space inside the cavity. The AC power generated by the piezoelectric energy harvesting unit is rectified and regulated, stored in the supercapacitor, and converted into a stable 3.3V voltage by the DC-DC circuit to power the entire node. In this embodiment, the intelligent sensing node is pre-installed with bolts at the key connection position of the reducer bearing housing. When the equipment is running, the vibration energy is collected and stored by the piezoelectric energy harvesting unit. The MCU processing unit wakes up from sleep according to a preset cycle (once every 10 minutes) and controls the MEMS sensing unit to collect vibration time-domain data and temperature data. After the data is collected, the MCU immediately performs preprocessing locally: first, high-frequency noise is removed by digital filter, and then the filtered vibration data is subjected to fast Fourier transform (FFT) to extract frequency domain features, including the amplitude of characteristic frequencies such as the first harmonic and the second harmonic, as well as the total vibration intensity. Finally, the preprocessed feature data packet is sent to the edge computing gateway in the field via the LoRa wireless communication unit. After transmission is complete, the MCU immediately enters a deep sleep state, with its extremely low standby power consumption maintained by the supercapacitor until the next wake-up cycle. The entire process requires no external cables or battery replacement.

[0032] The working principle of this invention is as follows: First, energy is harvested and stored. Equipment vibration causes slight vibration or deformation of the fastener body, which in turn causes deformation of the internal piezoelectric cantilever beam, generating AC power. The energy management unit rectifies, boosts, and regulates the voltage before charging the supercapacitor. Second, wake-up and sampling are performed. The timer inside the MCU processing unit overflows, waking it from sleep mode. The MCU processing unit detects the output voltage of the energy management unit. If the voltage reaches the working threshold, the three-axis MEMS sensing unit is activated to collect data. Third, an edge preprocessing stage is performed. The MCU processing unit performs zero-bias correction and bandpass filtering on the raw vibration data, and then performs FFT operation to extract spectral features. At the same time, the temperature data is digitally filtered and median-processed. Then, wireless transmission is performed. The MCU processing unit packages the processed feature data and sends it through the LoRa wireless communication unit. If the initial transmission fails, a random backoff retransmission mechanism can be used. Finally, the device enters sleep mode. After all tasks are completed, the MCU processing unit turns off the power to the MEMS sensing unit and the wireless communication unit, and enters a deep sleep state, waiting for the next wake-up.

[0033] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. The units and algorithm steps of the various examples described in the embodiments can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0034] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0035] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0036] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-powered intelligent sensing node embedded in a fastener for monitoring device status, characterized in that: The device includes a fastener body (1), a piezoelectric energy harvesting unit (3), an energy management and storage unit (5), a micro circuit board (4), a triaxial MEMS sensing unit, an MCU processing unit, and a wireless communication unit. The fastener body (1) has a sealed cavity. The piezoelectric energy harvesting unit (3) is located inside the sealed cavity and converts the mechanical energy of the device vibration into electrical energy. The energy management and storage unit (5) is electrically connected to the piezoelectric energy harvesting unit (3) and is used for rectification, voltage regulation, and energy storage. The micro circuit board (4) is fixedly installed inside the sealed cavity. The micro circuit board (4) is a high-density, fully integrated micro PCB structure with an outer diameter of no more than 12 mm. The micro circuit board (4) integrates all functional circuits for power management, sensor acquisition, main control operation, and wireless communication. The triaxial MEMS sensing unit is integrated on the micro circuit board (4). The triaxial MEMS sensing unit is used to collect triaxial vibration signals and temperature signals. The MCU processing unit is integrated on the micro circuit board (4). The wireless communication unit is integrated on the micro circuit board (4). The MCU processing unit is electrically connected to the triaxial MEMS sensing unit, the wireless communication unit, and the energy management and storage unit (5) respectively.

2. The self-powered intelligent sensing node embedded in a fastener for equipment status monitoring according to claim 1, characterized in that: The top of the sealed cavity of the fastener body (1) is provided with a cavity top cover (2). The fastener body (1) has the dual functions of mechanical fastening connection of equipment and in-situ working condition monitoring of sensing nodes. The sensing unit is rigidly integrated with the fastener and is used to collect the original pure working condition data of key stress points of the equipment.

3. The self-powered intelligent sensing node embedded in a fastener for equipment status monitoring according to claim 1, characterized in that: The fastener body (1) includes any one or more of the following: bolt, stud, positioning pin, pin shaft, flat key, spline, anti-loosening nut, retaining ring, expansion sleeve, rivet, and anchor bolt.

4. The self-powered intelligent sensing node embedded in a fastener for equipment status monitoring according to claim 1, characterized in that: The micro circuit board (4) is a circular high-density precision PCB with a maximum outer diameter of less than 12mm.

5. The self-powered intelligent sensing node embedded in a fastener for equipment status monitoring according to claim 1, characterized in that: The piezoelectric energy harvesting unit (3) is a piezoelectric ceramic cantilever beam energy harvesting structure.

6. The self-powered intelligent sensing node embedded in a fastener for equipment status monitoring according to claim 1, characterized in that: The energy management storage unit (5) includes a rectifier circuit, a DC-DC voltage regulator circuit, and a supercapacitor energy storage module.

7. A self-powered intelligent sensing node embedded in a fastener for equipment status monitoring according to claim 1, characterized in that: The wireless communication unit is a LoRa low-power wireless communication module.

8. A self-powered intelligent sensing node embedded in a fastener for equipment status monitoring according to claim 1, characterized in that: The MCU processing unit is configured to perform front-end preprocessing operations such as data filtering, FFT spectrum transformation, and vibration feature extraction.

9. A self-powered intelligent sensing node embedded in a fastener for equipment status monitoring according to claim 1, characterized in that: The overall structure can be pre-assembled as an integrated unit when the industrial equipment leaves the factory.

10. A self-powered intelligent sensing node embedded in a fastener for equipment status monitoring according to claim 1, characterized in that: The sealed cavity is filled with epoxy potting compound, which completely encapsulates all internal components. After the potting compound cures, it forms an integral sealed structure that fits tightly against the inner wall of the cavity. This integral sealed structure serves as a vibration buffer and a heat conduction pathway.

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