Pressure or pre-tightening force monitoring intelligent gasket using etching circuit

Abstract

The invention discloses a pressure or pre-tightening force monitoring intelligent gasket using an etching circuit, and the gasket comprises a pressed region disposed in the inner periphery, and the pressed region is provided with a variable capacitor whose capacitance value is in an expressible relationship with the pressure; the non-compression area is arranged on the periphery and provided with a metal substrate, and a frequency conversion circuit, a resonance circuit and a radio frequency antenna are etched on the metal substrate; the resonant circuit and a variable capacitor form an LC parallel resonant circuit based on an inductance element, the capacitance value of the capacitor is changed through the change of pressure or pre-tightening force borne by the variable capacitor, so that resonant signals with different resonant frequencies are generated, and the resonant signals are transmitted by a radio frequency antenna after being subjected to frequency conversion through a nonlinear electronic component of a frequency conversion circuit. Therefore, pressure or pre-tightening force monitoring of the to-be-measured bolt is realized. The intelligent gasket, especially the antenna circuit structure, is simplified, the circuit and the antenna obtained through the etching technology are low in power consumption and stable in signal, and the intelligent gasket has the advantages of being convenient to deploy, long in service life, easy to maintain and the like.

Description

Technical Field

[0001] The present invention relates to a radio frequency antenna etching process in the field of electronic engineering and pressure and bolt preload monitoring in industries such as rail transit, bridges and tunnels, hydropower, and wind power, and in particular to an intelligent gasket for pressure or preload monitoring using an etching circuit. Background Art

[0002] The design of traditional bolt washers is relatively simple. Its main function is to provide static mechanical support and isolation. It cannot cope with the complex stress changes and loose connection problems in actual applications. As a result, in key projects and equipment, the safety of bolt connections depends largely on the preload during initial installation and subsequent manual regular inspections. However, this method not only has the disadvantages of poor stability and time-consuming inspections, but also the intervention of human factors often leads to poor detection results and may even cause serious safety hazards. With the continuous development of industrial technology, the demand for monitoring bolt preload has become more and more urgent. At present, some improved preload monitoring technologies have appeared on the market.

[0003] However, these technologies still have many shortcomings. For example, although ultrasonic contact monitoring technology has advantages in accuracy, it relies on wired transmission, which not only increases the complexity of installation and maintenance, but also has problems such as difficult wiring and high costs in large-scale engineering applications.

[0004] The above limitations indicate that the existing technology still lacks a reliable, simple and high-precision solution that takes into account both power consumption cost and efficiency when dealing with bolt preload monitoring in complex engineering environments. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a pressure or preload monitoring smart gasket using an etched circuit, which simplifies the circuit structure of the smart gasket, especially the antenna. The circuit and antenna obtained by etching technology have low power consumption and stable signal. It is also easy to deploy, has a long service life, and is easy to maintain. It is widely used in rail transit, bridges and tunnels, hydropower and other fields.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A smart gasket for monitoring pressure or preload using an etched circuit is sleeved on a bolt to be tested, the smart gasket comprising: a pressure zone arranged at an inner periphery, the pressure zone being provided with a variable capacitor whose capacitance value is in an expressible relationship with the pressure applied; a non-pressure zone arranged at an outer periphery, the non-pressure zone being provided with a metal substrate, the metal substrate being etched with a frequency conversion circuit, a resonance circuit and a radio frequency antenna; the resonance circuit is based on an LC parallel resonance circuit composed of an inductor element and a variable capacitor, the capacitance value changes due to the change in pressure or preload applied to the variable capacitor, thereby generating resonance signals with different resonance frequencies, which are frequency-converted by nonlinear electronic components of the frequency conversion circuit and then transmitted by the radio frequency antenna, thereby realizing pressure or preload monitoring of the bolt to be tested.

[0008] Furthermore, the variable capacitor in the pressure zone includes a parallel plate capacitor, the surface of which is wrapped with a buffer protection material, which can produce elastic deformation after being compressed, and the capacitance is in an expressible relationship with the pressure or preload force.

[0009] Furthermore, the method for manufacturing the metal substrate in the non-pressurized area includes: pressing a metal foil and a biaxially oriented polyester (PET) film together and curing them at high temperature.

[0010] Furthermore, the etching method of the frequency conversion circuit, resonant circuit and radio frequency antenna on the metal substrate includes: attaching a photosensitive dry film or printing photosensitive ink on the metal substrate and performing an etching process, and the etching process includes exposure, development, etching, film stripping, water washing and drying.

[0011] Furthermore, the radio frequency antenna in the non-pressure zone is electrically connected to the input and output ends of the frequency conversion circuit, and the radio frequency antenna is coiled around the outermost diameter of the non-pressure zone to maximize the receiving circle of the radio frequency antenna.

[0012] Furthermore, the radio frequency antenna is obtained by etching on a metal substrate through an etching process, or by embedding an existing packaged antenna in a non-pressurized area.

[0013] Furthermore, the smart gasket also includes an expansion layer, which is arranged at the periphery of the non-pressurized area through an inlay process and can directly integrate a frequency conversion circuit, a resonant circuit and a radio frequency antenna.

[0014] Furthermore, the resonant frequency generated by the LC parallel resonant circuit changes with the capacitance value of the variable capacitor and follows the following relationship:

[0015]

[0016] Where f is the resonant frequency, L is the inductance of the inductor, and C is the capacitance of the variable capacitor.

[0017] Furthermore, the frequency conversion circuit and the resonance circuit can be driven to work by an input signal received by a radio frequency antenna, or by adding a super capacitor and an energy replenishment module.

[0018] Furthermore, the input signal and the resonance signal of the LC parallel resonance circuit are mixed based on the nonlinear characteristics of the nonlinear electronic components of the frequency conversion circuit, and the mixed signal is transmitted and outputted through the radio frequency antenna.

[0019] The beneficial effects of the present invention are:

[0020] 1. Compared with traditional gaskets, the smart gasket of the present invention can realize remote, passive, wireless and real-time data transmission by exciting the sensing device through microwave energy without changing the gasket and bolt structure.

[0021] 2. Compared with the existing bolt smart gaskets, the present invention simplifies the antenna circuit structure. The structural design of the smart gasket fully considers the diversity and complexity of the application environment. The antenna and circuit are integrated and etched or embedded on the substrate plate in the non-pressure area outside the gasket by using advanced etching technology or packaging antenna technology, so that stable signal transmission can be achieved without additional components. The etched circuit and antenna have high precision, low power consumption, simple and stable structure, low maintenance cost, and can also integrate more circuit elements by embedding expansion layers to expand the function of the gasket, which is highly flexible.

[0022] 3. The smart gasket of the present invention not only has significant advantages in accuracy and reliability, but also has a simple structure and is easy to install. Users only need to replace traditional gaskets with smart gaskets to achieve real-time monitoring of bolt preload, significantly reducing the workload of manual inspection and the risk of missed inspections. Due to its passive design, the smart gasket has a long service life and low maintenance cost, and is suitable for fields with extremely high safety requirements such as rail transit, bridges and tunnels, aerospace, water conservancy and hydropower, and nuclear power plants. By combining traditional mechanical components with modern information technology, the present invention provides a new solution for the safety management of bolted connections, which has broad application prospects and market potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of a pressure or preload monitoring smart gasket using an etched circuit provided in an embodiment of the present invention;

[0024] Figure 2 A structural block diagram of a pressure or preload monitoring intelligent gasket using an etched circuit provided in an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of a pressure or preload monitoring smart gasket plus an expansion layer using an etched circuit provided in an embodiment of the present invention;

[0026] Figure 4 A 3D schematic diagram of a pressure or preload monitoring smart gasket plus an expansion layer using an etched circuit provided in an embodiment of the present invention;

[0027] Figure 5 A schematic diagram of the properties of a rubber insulating material used in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, this embodiment provides a pressure or preload monitoring smart gasket using an etched circuit, including a pressure-bearing area arranged in the inner periphery and a non-pressure-bearing area in the outer periphery, wherein the pressure-bearing area is provided with a variable capacitor whose capacitance value is in an expressible relationship with the pressure, and has the function of a conventional gasket; the non-pressure-bearing area is provided with a metal substrate, and the metal substrate is provided with an etched frequency conversion circuit, a resonant circuit and a radio frequency antenna; as shown Figure 2 As shown, the inductor element of the resonant circuit is connected in parallel with the variable capacitor to form an LC parallel resonant circuit. The pressure or preload on the variable capacitor changes, causing the capacitance to change, thereby generating resonant signals with different resonant frequencies. The signals are converted by nonlinear electronic components and then transmitted by the radio frequency antenna, thereby realizing the pressure or preload monitoring of the bolt to be tested.

[0030] The smart gasket of this embodiment can input the microwave signal sent from the outside into the frequency conversion circuit through the radio frequency antenna. The inductance element and nonlinear electronic components of the frequency conversion circuit will generate abundant tuned waves. When the frequency of the tuned wave is consistent with the resonant frequency of the LC parallel resonant circuit, the LC parallel resonant circuit will be in a resonant state and generate a resonant frequency. At the same time, the nonlinear electronic components in the frequency conversion circuit work in the nonlinear region, so that the microwave signal and the resonant frequency are mixed / converted. The mixed / converted signal can be sent through the radio frequency antenna to achieve remote transmission. By analyzing the mixed / converted signal, the pressure on the gasket can be obtained, and the bolt preload can be calculated. By using etching technology to make the frequency conversion circuit, the inductance element of the resonant circuit and the radio frequency antenna, low power consumption and high precision that could not be achieved by previous gasket designs can be achieved.

[0031] It should be noted that the inductor element of the frequency conversion circuit can be a component or a parasitic inductor in the circuit, and the connection method with the nonlinear electronic component is diversified.

[0032] Preferably, the smart gasket of this embodiment can be inlaid with a circle of expansion layers on the periphery using an inlay process, such as Figure 3 and Figure 4 As shown, it is used to etch supplementary circuits and embed other components, so as to achieve the effect of expanding the functions of the smart gasket.

[0033] In this embodiment, the variable capacitor in the pressure zone has a certain resilience. Preferably, the variable capacitor can be composed of a varistor capacitor, including a three-layer structure, the middle layer is an insulating material, and the upper and lower layers are metal materials, which can be equivalent to a parallel plate capacitor. At the same time, the capacitance value of the variable capacitor is in an expressible relationship with the pressure, which is specifically determined by the properties of the insulating material used in the middle layer. The insulating material used in this embodiment is a rubber material, and its deformation-strain characteristic curve is shown in the figure below: Figure 5 shown.

[0034] Preferably, the metal substrate in the non-pressurized area can be formed by laminating a metal foil and a biaxially oriented polyester PET film together and curing at high temperature; the inductor element of the frequency conversion circuit, the resonant circuit and the radio frequency antenna can be formed by attaching a photosensitive dry film or printing photosensitive ink on the non-pressurized area, and then etching through a series of steps such as continuous automatic exposure, imaging, etching, film stripping, washing, and drying. It should be noted that some of the steps can be performed in other orders or simultaneously.

[0035] In this embodiment, the RF antenna in the non-pressurized area is used for signal reception and transmission, connecting the input and output ends of the frequency conversion circuit, or using only one port for input and output at the same time. Preferably, in order to ensure that the antenna receiving circle is larger, the RF antenna is coiled around the outermost diameter of the non-pressurized area. Preferably, the RF antenna can not only be obtained by etching on the metal substrate through an electronic etching process, but also by inlaying an existing packaged antenna in the annular etching area as needed. The specific number of turns and diameter of the RF antenna can be in the expansion area, such as Figure 3 and Figure 4 As shown, the transmission distance and transmission efficiency can be adjusted according to the specific application scenario through antenna design.

[0036] It should be noted that the inductance element L of the resonant circuit is selected as an inductor with specified parameters, and the capacitance C is composed of a variable capacitor as a sensing device. Its resonant frequency changes with the capacitance value of the variable capacitor and follows the following relationship:

[0037]

[0038] Among them, f is the resonant frequency, L is the inductance value of the inductor element of the resonant circuit, and C is the capacitance value of the variable capacitor.

[0039] Preferably, the frequency conversion circuit and the LC parallel resonant circuit of this embodiment can be stimulated to work by the input signal received by the radio frequency antenna, and can also be stimulated to work by adding a super capacitor and an energy compensation module.

[0040] Specifically, taking the bolt pressure monitoring gasket device as an example, in the machine connection bolt preload monitoring in the equipment manufacturing scenario, the frequency of f can be remotely sent to 1 The microwave signal is received by the RF antenna in the non-pressurized area of ​​the smart gasket, and the frequency is converted through the frequency conversion circuit, the inductor element L of the resonant circuit and the variable capacitor C, and then the frequency is output through the RF antenna. 2 According to the pressure-capacitance curve of the smart gasket, the pressure on the smart gasket can be calculated, such as Figure 5 shown.

[0041] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A pressure or preload monitoring smart gasket using an etched circuit, which is sleeved on a bolt to be tested, characterized in that: The smart gasket comprises: A pressure zone is arranged in the inner periphery, wherein the pressure zone is provided with a variable capacitor whose capacitance value is in an expressible relationship with the pressure; It is arranged in the non-pressure zone of the periphery, and the non-pressure zone is provided with a metal substrate, on which a frequency conversion circuit, a resonance circuit and a radio frequency antenna are etched; the resonance circuit is based on an LC parallel resonance circuit composed of an inductor element and a variable capacitor, and the capacitance value changes due to the pressure or preload force applied to the variable capacitor, thereby generating a resonance signal with a different resonance frequency, which is converted by the nonlinear electronic components of the frequency conversion circuit and then transmitted by the radio frequency antenna, thereby realizing the pressure or preload force monitoring of the bolt to be tested.

2. A pressure or preload monitoring smart gasket using an etched circuit according to claim 1, characterized in that: The variable capacitor in the pressure zone includes a parallel plate capacitor, the surface of which is wrapped with a buffer protection material, which can produce elastic deformation after being compressed, and the capacitance is in an expressible relationship with the pressure or preload force.

3. A pressure or preload monitoring smart gasket using an etched circuit according to claim 1, characterized in that: The method for manufacturing the metal substrate in the non-pressurized area comprises: pressing a metal foil and a biaxially oriented polyester (PET) film together and curing them at high temperature.

4. A pressure or preload monitoring smart gasket using an etched circuit according to claim 1, characterized in that: The etching method of the frequency conversion circuit, the resonant circuit and the radio frequency antenna on the metal substrate includes: attaching a photosensitive dry film or printing a photosensitive ink on the metal substrate and performing an etching process, wherein the etching process includes exposure, development, etching, film stripping, water washing and drying.

5. A pressure or preload monitoring smart gasket using an etched circuit according to claim 1, characterized in that: The radio frequency antenna in the non-pressure zone is electrically connected to the input and output ends of the frequency conversion circuit, and the radio frequency antenna is coiled around the outermost diameter of the non-pressure zone to maximize the receiving circle of the radio frequency antenna.

6. A pressure or preload monitoring smart gasket using an etched circuit according to claim 1, characterized in that: The radio frequency antenna is obtained by etching on a metal substrate through an etching process, or by embedding an existing packaged antenna in a non-pressurized area.

7. A pressure or preload monitoring smart gasket using an etched circuit according to claim 1, characterized in that: The smart gasket also includes an expansion layer, which is arranged on the periphery of the non-pressurized area through an inlay process and can directly integrate a frequency conversion circuit, a resonant circuit and a radio frequency antenna.

8. A pressure or preload monitoring smart gasket using an etched circuit according to claim 1, characterized in that: The resonant frequency generated by the LC parallel resonant circuit changes with the capacitance value of the variable capacitor and follows the following relationship: Where f is the resonant frequency, L is the inductance of the inductor, and C is the capacitance of the variable capacitor.

9. A pressure or preload monitoring smart gasket using an etched circuit according to claim 1, characterized in that: The frequency conversion circuit and the resonance circuit can be driven to work by an input signal received by a radio frequency antenna, or by adding a super capacitor and an energy replenishment module.

10. A pressure or preload monitoring smart gasket using an etched circuit according to claim 1, characterized in that: The input signal and the resonant signal of the LC parallel resonant circuit are mixed based on the nonlinear characteristics of the nonlinear electronic components of the frequency conversion circuit, and the mixed signal is transmitted and output through the radio frequency antenna.

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