Gasketed sensor and method of making and using same

Abstract

The application relates to the technical field of thin film sensors, in particular to a gasket type sensor and a preparation method and application thereof. The gasket type sensor is used to solve the problems that a thin film sensor cannot accurately obtain bolt pretightening force under static state and the setting of the thin film sensor is not conducive to the rigid retention of the bolt in the prior art. The gasket type sensor comprises a gasket body, the pressure receiving surface of the gasket body is provided with a groove, and a thin film sensor. The thin film sensor comprises a pressure variable sensing layer, the pressure variable sensing layer is arranged in the groove, and the thickness direction of the pressure variable sensing layer is the same as the thickness direction of the gasket body. The height difference between the surface of the pressure variable sensing layer far from the bottom surface of the groove and the pressure receiving surface of the gasket body is greater than or equal to 0 and less than or equal to 0.1 microns. The thin film sensor is used for detecting the pressure receiving force of the gasket body according to the electrical signal output by the pressure variable sensing layer.

Description

Technical Field

[0001] This application relates to the field of thin-film sensor technology, and in particular to a pad-type sensor, its preparation method, and its application. Background Technology

[0002] In large-scale engineering equipment such as wind power generation and petrochemicals, a large number of large-diameter bolts are required, and the magnitude of the bolt preload directly determines whether the components are tightly connected. However, over time, factors such as washer fatigue, corrosion, and weathering can reduce the bolt preload, leading to the loss of locking function. Furthermore, when bolts are on continuously operating equipment, the load on the bolts changes constantly, which may also cause fatigue fracture, thread sealant loss, and loose threads.

[0003] Thin-film sensors primarily detect pressure on the substrate by contacting it with a multi-layered composite membrane. However, current methods for detecting bolt preload using thin-film sensors still rely on integrating the sensor onto the bolt's stress surface or adding other components between the stress surface and the substrate. Integrating the sensor requires creating grooves on the stress surface, which affects the bolt's rigidity and hinders its functionality, limiting its application to larger structures. Adding other components between the stress surface and the substrate requires supporting the sensor, especially when these components are elastic bodies. During detection, the bolt preload must be determined based on the elastic body's deformation, making it difficult to accurately measure the bolt preload under static conditions. Summary of the Invention

[0004] Based on this, this application provides a gasket-type sensor, its preparation method, and its application to solve the problems in related technologies where thin-film sensors cannot accurately obtain the bolt preload under static conditions, and where the setting of thin-film sensors is not conducive to maintaining the rigidity of the bolt itself.

[0005] In a first aspect, a pad-type sensor is provided, comprising:

[0006] The gasket body has a groove on its pressure-bearing surface;

[0007] A thin-film sensor includes a pressure-sensitive layer disposed in a groove, wherein the thickness direction of the pressure-sensitive layer is the same as the thickness direction of the pad body.

[0008] The height difference between the surface of the pressure-sensitive layer away from the bottom of the groove and the pressure-bearing surface of the gasket body is greater than or equal to 0 and less than or equal to 0.1 μm; the thin-film sensor is used to detect the pressure on the gasket body based on the electrical signal output by the pressure-sensitive layer.

[0009] Optionally, the surface of the pressure-sensitive layer away from the bottom of the groove is flush with the pressure-bearing surface of the gasket body;

[0010] And / or,

[0011] The depth of the groove is 10–50 μm.

[0012] Optionally, the voltage-transfer sensing layer includes a voltage-transfer resistive layer, which is disposed on the bottom surface of the groove, and the shape enclosed by the voltage-transfer resistive layer and the bottom edge of the groove is the same.

[0013] Alternatively, the groove extends in a meandering manner on the gasket body;

[0014] The voltage-changing resistor layer has a first pattern, which extends in a meandering manner on the bottom surface of the groove;

[0015] And / or,

[0016] The voltage-changing resistor layer can be a single-layer structure or a multi-layer structure. The single-layer structure of the voltage-changing resistor layer includes any one of Ti metal thin film, manganese copper alloy thin film, nickel carbon alloy thin film, silicon carbide thin film and graphene-metal composite thin film. In the multi-layer structure of the voltage-changing resistor layer, the material of each layer is independently selected from any one of Ti metal thin film, manganese copper alloy thin film, nickel carbon alloy thin film, silicon carbide thin film and graphene-metal composite thin film.

[0017] And / or,

[0018] The thickness of the voltage-varistor layer is 400–800 nm;

[0019] And / or,

[0020] The voltage-changing resistor layer is in the form of strips, with a length of 1.5 to 2 mm and a width of 50 to 200 μm.

[0021] Optionally, the gasket body may be conductive;

[0022] The voltage transformer induction layer further includes: a first insulating layer, which is disposed on the side of the voltage transformer resistor layer near the bottom of the groove, and the first insulating layer covers the bottom and side surfaces of the groove;

[0023] Optionally, the material of the pad body includes one or more of doped silicon and metallic materials;

[0024] Alternatively, the material of the gasket body may include one or more of aluminum and copper.

[0025] Optionally, the first insulating layer is a single-layer structure or a multi-layer structure. The material of the single-layer structure of the first insulating layer is selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ. In the multi-layer structure of the first insulating layer, the material of each layer is independently selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ.

[0026] And / or,

[0027] The thickness of the first insulating layer is 3–6 μm.

[0028] Optionally, the thin-film sensor further includes: a measurement circuit and a lead layer electrically connected to the piezoelectric resistive layer;

[0029] The lead layer is used to connect the electrical signal output from the piezoresistive layer to the measurement circuit, and the thin-film sensor detects the pressure on the gasket body through the measurement circuit.

[0030] Optionally, the measurement circuit is a Wheatstone bridge circuit, and the voltage transformer layer is connected in the Wheatstone bridge circuit as the measuring resistor.

[0031] Optionally, the lead layer is disposed on the side of the varistor layer away from the bottom surface of the groove, and is electrically connected to the varistor layer through a conductive sheet;

[0032] The voltage transformer induction layer also includes: a second insulating layer and a third insulating layer disposed between the voltage transformer resistor layer and the lead layer;

[0033] The second insulating layer has through holes for connecting the conductive sheet and the lead layer, and the second insulating layer is arranged around the conductive sheet. The third insulating layer covers the remaining area of ​​the voltage transformer induction layer except for the area where the conductive sheet and the second insulating layer are located.

[0034] Optionally, the material of the conductive sheet includes one or more of Au, silver, and copper;

[0035] And / or,

[0036] The thickness of the conductive sheet is 500 nm to 4 μm;

[0037] And / or,

[0038] The second insulating layer and / or the third insulating layer are single-layer or multi-layer structures. The material of the single-layer structure of the second insulating layer and / or the third insulating layer is selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ. In the multi-layer structure of the second insulating layer and / or the third insulating layer, the material of each layer is independently selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ.

[0039] And / or,

[0040] The thicknesses of the second and third insulating layers are independently 3–6 μm.

[0041] Optionally, the gasket body is annular and sheet-shaped, and the pressure-bearing surface is at least one of two surfaces of the sheet that are arranged opposite each other along its thickness direction;

[0042] There are two grooves and two pressure transducer layers, which are respectively located on opposite sides of the gasket body along its center.

[0043] Secondly, a method for fabricating a pad-type sensor is provided, comprising:

[0044] A groove is made on the pressure-bearing surface of the gasket body;

[0045] A pressure-sensitive layer for a thin-film sensor is fabricated within a groove, such that the thickness direction of the pressure-sensitive layer is the same as the thickness direction of the gasket body, and the height difference between the pressure-bearing surface of the gasket body and the outer surface of the pressure-sensitive layer is greater than or equal to 0 and less than or equal to 0.1 μm. The thin-film sensor is used to detect the pressure on the gasket body based on the electrical signal output by the pressure-sensitive layer.

[0046] Optionally, the gasket body is conductive; a groove is formed on the pressure-bearing surface of the gasket body, including:

[0047] Grooves are etched on the pressure-bearing surface of the gasket body using an electrolytic method.

[0048] Optionally, grooves are etched on the pressure-bearing surface of the gasket body using an electrolytic method, including:

[0049] Using the gasket body as the anode, the pressure-bearing surface of the gasket body, except for the area where the groove is located, is covered, so that the part of the pressure-bearing surface of the gasket body located in the area where the groove is located undergoes an electrolytic reaction, and the groove is etched.

[0050] Optionally, the gasket body is used as the anode, and the pressure-bearing surface of the gasket body, excluding the area where the groove is located, is covered, so that the portion of the pressure-bearing surface of the gasket body located in the area where the groove is located undergoes an electrolytic reaction, etching the groove, including:

[0051] A mask layer is fabricated on the cathode, and the pattern of the exposed portion of the mask layer is the same as the pattern of the groove.

[0052] The mask layer is placed between the anode and the gasket body, and the anode and the gasket body are fixed. The mask layer exposes the part of the gasket body in the area where the pressure surface of the gasket body is located.

[0053] Electrolyte is injected into the region between the cathode and the pad body, which is enclosed by the mask layer;

[0054] A groove is created by passing an electric current through the anode and cathode.

[0055] Optionally, the electrolyte includes: an aqueous solution of NaNO3 and / or NaClO3;

[0056] And / or,

[0057] The concentration of the electrolyte is 0.03–0.1 M;

[0058] And / or,

[0059] The current density is 10–500 A / m 2 ;

[0060] And / or,

[0061] The power supply used in the power supply is a pulse power supply with a power of 0.5 to 2W; the frequency of the pulse power supply is 10 to 500Hz, and the duty cycle is 5% to 50%.

[0062] Optionally, a pressure-sensitive layer for the thin-film sensor is fabricated within the groove, comprising:

[0063] The thin films comprising the pressure transducer layer are prepared by deposition and patterning processes, such that the surface of the pressure transducer layer away from the groove is higher than the pressure-bearing surface of the gasket body by a predetermined height;

[0064] The surface of the pressure transducer layer is polished so that the height difference between the surface of the pressure transducer layer away from the groove and the pressure-bearing surface of the gasket body is greater than or equal to 0 and less than or equal to 0.1 μm.

[0065] Optionally, the preset height is 1 to 100 μm.

[0066] Thirdly, an application of the gasket-type sensor as described in the first aspect in bolt preload sensing is provided.

[0067] In the pad-type sensor provided in this application, by setting a groove on the pressure-bearing surface of the pad body and placing the pressure transducer layer contained in the thin-film sensor in the groove, the pad body and the thin-film sensor can be integrated together. This solves the problem in related technologies where the reduction in rigidity of bolt fasteners caused by setting grooves on the pressure-bearing surface of bolt fasteners limits their applicability to installation environments of large structural components. Furthermore, by limiting the height difference between the surface of the pressure transducer layer away from the bottom of the groove and the pressure-bearing surface of the pad body to a range greater than or equal to 0 and less than or equal to 0.1 μm, the pressure transducer layer can be subjected to more uniform force, and the problem of wear caused by the pressure transducer layer being too high can be avoided.

[0068] In addition, by integrating the gasket body and the thin-film sensor together, the thin-film sensor can be embedded in the gasket body itself. The structure is simple and highly adaptable, and can be used to detect the bolt preload of structural components of different sizes. Compared with the use of elastic elements to support the thin-film sensor in related technologies, it can also accurately obtain the bolt preload of the bolt fastener under static conditions. Attached Figure Description

[0069] Figure 1 This is a schematic diagram of the structure of a pad-type sensor provided in an embodiment of this application;

[0070] Figure 2 This is a schematic diagram of the structure of a pad-type sensor in use, provided in an embodiment of this application.

[0071] Figure 3 An exploded view of a pad-type sensor provided in an embodiment of this application;

[0072] Figure 4 This is a schematic diagram of the structure of a voltage transformer layer provided in an embodiment of this application;

[0073] Figure 5 This is a schematic flowchart illustrating a method for preparing a groove in a pad-type sensor according to an embodiment of this application. Detailed Implementation

[0074] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0075] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0076] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0077] In the accompanying drawings, the size of the constituent elements, the thickness of the layers, or the area are sometimes exaggerated for clarity. Therefore, one aspect of this application is not necessarily limited to these dimensions, and the shapes and sizes of the components in the drawings do not reflect true proportions. Furthermore, the drawings schematically illustrate ideal examples, and one aspect of this application is not limited to the shapes or values ​​shown in the drawings.

[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0079] Based on the above problems, some embodiments of this application provide a pad-type sensor 10, such as... Figure 1 As shown, the pad-type sensor 10 includes: a pad body 1 and a thin-film sensor 2, wherein a groove S is provided on the pressure-receiving surface 1a of the pad body 1; as shown Figure 1 As shown, the thin-film sensor 2 includes a pressure-sensitive layer 21, which is disposed in the groove S, and the thickness direction of the pressure-sensitive layer 21 is the same as the thickness direction of the gasket body 1; wherein, the height difference between the surface 21a of the pressure-sensitive layer 21 away from the bottom surface of the groove S and the pressure-bearing surface 1a of the gasket body 1 is greater than or equal to 0 and less than or equal to 0.1 μm, and the thin-film sensor 2 is used to detect the pressure on the gasket body 1 according to the electrical signal output by the pressure-sensitive layer 2.

[0080] In some embodiments, such as Figure 1 As shown, the gasket body 1 is annular and sheet-shaped, and the pressure-bearing surface 1a is at least one of two surfaces of the sheet that are arranged opposite each other along its thickness direction.

[0081] In these embodiments, such as Figure 2As shown, in use, the gasket body 1 can be inserted through the nut 20. When the nut 20 passes through the component and is connected to the bolt 30, the pressure-bearing surface of the gasket body 1 is in direct contact with the component or the nut 20, thereby allowing the preload of the bolt 30 to be detected.

[0082] In some embodiments, such as Figure 1 and Figure 2 As shown, there are two grooves S and two pressure transducer layers 21, which are respectively disposed on opposite sides of the gasket body 1 along its center.

[0083] In these embodiments, by setting two grooves S and pressure sensing layers 21, and placing the two grooves S and pressure sensing layers 21 on opposite sides of the gasket body 1 along its center, the bolt preload can be detected by the two sets of pressure sensing layers 21, thereby timely detection of possible measurement errors in the pressure sensing layers 21 and improving detection accuracy.

[0084] In the pad-type sensor 10 provided in this application, by setting a groove S on the pressure-bearing surface 1a of the pad body 1 and placing the pressure transducer layer 21 included in the thin film sensor 2 in the groove S, the pad body 1 and the thin film sensor 2 can be integrated together. This solves the problem in the related art that the reduction in rigidity of bolt fasteners caused by opening grooves on the pressure-bearing surface of bolt fasteners can only be used in installation environments of large structural components. Furthermore, by limiting the height difference between the surface 21a of the pressure transducer layer 21 away from the bottom surface of the groove S and the pressure-bearing surface 1a of the pad body 1 to a range greater than or equal to 0 and less than or equal to 0.1 μm, the pressure transducer layer 21 can be subjected to more uniform force. On the other hand, it can avoid the problem of the pressure transducer layer 21 being too high and easily causing wear.

[0085] In addition, by integrating the gasket body 1 and the thin film sensor 2 together, the thin film sensor 2 can be embedded and manufactured by utilizing the thin film properties of the gasket body 1 itself. The structure is simple and highly adaptable, and can be used to detect the bolt preload of structural components of different sizes. Compared with the use of elastic elements to support the thin film sensor in related technologies, it can also accurately obtain the bolt preload of the bolt fastener under static conditions.

[0086] In some embodiments, such as Figure 1 As shown, the surface 21a of the pressure transducer layer 21 away from the bottom surface of the groove S is flush with the pressure-bearing surface 1a of the gasket body 1.

[0087] In these embodiments, by making the surface 21a of the pressure sensing layer 21 away from the bottom surface of the groove S flush with the pressure-bearing surface 1a of the gasket body 1, wear on the pressure sensing layer 2 can be further reduced. On the other hand, since the surface 21a of the pressure sensing layer 21 away from the bottom surface of the groove S is flush with the pressure-bearing surface 1a of the gasket body 1, the pressure sensing layer 21 and the pressure-bearing surface 1a of the gasket body 1 can be in the same plane, thereby further improving the uniformity of force on the pressure sensing layer 21.

[0088] In some embodiments, the depth of the groove S is 10–50 μm.

[0089] In some embodiments, such as Figure 2 , Figure 3 and Figure 4 As shown, the voltage-transfer sensing layer 21 includes a voltage-transfer resistor layer 211, which is disposed on the bottom surface of the groove S, and the shape enclosed by the voltage-transfer resistor layer 211 and the bottom edge of the groove S is the same.

[0090] In these embodiments, a piezoresistive layer 211 is employed. The working principle of the piezoresistive layer 211 is as follows: when subjected to pressure, the piezoresistive layer 211 is stretched or compressed, causing deformation and resulting in a change in resistance applied to it. Therefore, the force on the piezoresistive sensing layer 21 can be detected by detecting the voltage change applied to the piezoresistive layer 211. Since the shape enclosed by the piezoresistive layer 211 and the bottom edge of the groove S is identical, the bottom space of the groove S can be fully utilized to fabricate the piezoresistive layer 211, thereby increasing the force-bearing area of ​​the piezoresistive layer 211 and improving detection accuracy.

[0091] In some embodiments, such as Figure 3 and Figure 4 As shown, the groove S extends in a meandering manner on the gasket body 1; as Figure 3 and Figure 4 As shown, the voltage transformer layer 211 has a first pattern, which extends in a meandering manner on the bottom surface of the groove S.

[0092] In these embodiments, the voltage transformer layer 211 may extend in a meandering manner, thereby enabling more effective detection of deformation caused by stretching or compressing of the voltage transformer layer 211.

[0093] In some embodiments, the voltage-changing resistor layer 211 is a single-layer structure or a multi-layer structure. The single-layer structure of the voltage-changing resistor layer 211 includes any one of Ti metal thin film, manganese copper alloy thin film, nickel carbon alloy thin film, silicon carbide thin film and graphene-metal composite thin film. In the multi-layer structure of the voltage-changing resistor layer 211, each layer is independently selected from any one of Ti metal thin film, manganese copper alloy thin film, nickel carbon alloy thin film, silicon carbide thin film and graphene-metal composite thin film.

[0094] It should be noted that the graphene-metal composite film can be a film formed by a composite material of graphene and metal, or a film formed by stacking graphene and metal. An example of a composite material of graphene and metal is a material in which graphene and metal are composited in an immersion manner.

[0095] In some embodiments, the thickness of the voltage-varistor layer 211 is 400–800 nm.

[0096] In some embodiments, such as Figure 3 and Figure 4 As shown, the voltage-changing resistor layer 211 is strip-shaped, with a length of 1.5 to 2 mm and a width of 50 to 200 μm.

[0097] In these embodiments, by setting the voltage transformer layer 211 as a strip, since the length of the strip is 1.5 to 2 mm and the width is 50 to 200 μm, the voltage change can be increased more significantly when the voltage transformer layer 211 is deformed along the length of the strip, thereby improving the detection accuracy.

[0098] It should be noted that, for example Figure 3 and Figure 4 As shown, when the first pattern of the voltage transformer layer 211 extends in a meandering manner on the bottom surface of the groove S, the voltage transformer layer 211 can also be regarded as a strip. At this time, the length of the strip refers to the dimension of the voltage transformer layer 211 along its extension direction, and the width refers to the dimension of the voltage transformer layer 211 perpendicular to the extension direction.

[0099] In some embodiments, such as Figure 3 As shown, the gasket body 1 is conductive; the voltage transformer sensing layer 21 further includes: a first insulating layer 212, which is disposed on the side of the voltage transformer resistive layer 211 near the bottom surface of the groove S, and the first insulating layer 212 covers the bottom and side surfaces of the groove S.

[0100] In these embodiments, the first insulating layer 212 can insulate the voltage transformer layer 211 and the gasket body 1, preventing the voltage transformer layer 211 and the gasket body 1 from coming into direct contact.

[0101] In some alternative embodiments, the material of the gasket body 1 includes one or more of doped silicon and metallic materials.

[0102] The doped silicon can be either phosphorus-doped or boron-doped, and no specific limitation is made here. The doping concentration can be reasonably selected according to the conductivity requirements.

[0103] In some embodiments, the material of the gasket body 1 includes aluminum and / or copper.

[0104] In some embodiments, the first insulating layer 212 is a single-layer structure or a multi-layer structure. The material of the single-layer structure of the first insulating layer 212 is selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ. In the multi-layer structure of the first insulating layer 212, the material of each layer is independently selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ.

[0105] In some embodiments, the thickness of the first insulating layer 212 is 3 to 6 μm.

[0106] In some embodiments, such as Figure 2 and Figure 3 As shown, the thin-film sensor 2 also includes a measurement circuit 22 and a lead layer 23 electrically connected to the piezoresistive layer 211; the lead layer 23 is used to connect the electrical signal output by the piezoresistive layer 211 to the measurement circuit 22, and the thin-film sensor 2 detects the pressure on the gasket body 1 through the measurement circuit 22.

[0107] In some embodiments, such as Figure 2 As shown, the measurement circuit 22 is a Wheatstone bridge circuit, and the voltage transformer layer 211 is connected in the Wheatstone bridge circuit as the measuring resistor (for example, if there are two voltage transformer layers 211, represented by R1 and R5 respectively).

[0108] In these embodiments, such as Figure 2 As shown, the Wheatstone bridge circuit includes six standard resistors. The resistance values ​​of every three standard resistors are connected to a piezoresistive layer 211 on the PCB board to form a sub-circuit. For example, R2, R3, R4 and R1 are connected to form a Wheatstone bridge sub-circuit, and R6, R7, R8 and R5 are connected to form a Wheatstone bridge sub-circuit. When the resistance of the piezoresistive layer 211 changes due to the piezoresistive effect, the bridge voltage in the Wheatstone bridge circuit on the PCB board will change. The change in voltage is related to the pressure on the piezoresistive layer 211. Therefore, the pressure on the piezoresistive layer 211 can be detected based on the output voltage of the bridge circuit, thereby enabling the detection of changes in bolt preload.

[0109] In some embodiments, such as Figure 3As shown, the lead layer 23 is disposed on the side of the voltage transformer layer 211 away from the bottom surface of the groove S, and is electrically connected to the voltage transformer layer 211 through the conductive sheet 213 disposed between the lead layer 23 and the voltage transformer layer 211.

[0110] The voltage transformer induction layer 21 further includes a second insulating layer 214 and a third insulating layer 215 disposed between the voltage transformer resistor layer 211 and the lead layer 23;

[0111] The second insulating layer 214 has through holes for connecting the conductive sheet 213 and the lead layer 23, and the second insulating layer 214 is arranged around the conductive sheet 213. The third insulating layer 215 covers the remaining area of ​​the voltage transformer induction layer 21 except for the area where the conductive sheet 213 and the second insulating layer 214 are located.

[0112] In these embodiments, by providing a conductive sheet 213 between the lead layer 23 and the piezoresistive layer 211, the lead layer 23 and the piezoresistive layer 211 can be electrically connected, and by providing a second insulating layer 214 and a third insulating layer 215, the surface of the piezoresistive sensing layer 21 can be protected.

[0113] The aforementioned conductive sheet 213 can be two, and the two conductive sheets 213 are respectively disposed at the two end positions of the voltage transformer layer 211. In this way, the voltage transformer layer 211 can be connected as a measuring resistor in the Wheatstone bridge circuit. At this time, the aforementioned second insulating layer 214 can include two insulating blocks disposed on the same layer. The two insulating blocks can be respectively disposed around the two conductive sheets 213. By disposing the third insulating layer 215 in the remaining area outside the area where the conductive sheets 213 and the second insulating layer 214 are located, it is possible to maintain coverage of different positions in the voltage transformer sensing layer 21, thereby reducing the thickness difference of different positions in the voltage transformer sensing layer 21 and improving the uniformity of sensing at different positions in the voltage transformer sensing layer 21.

[0114] In some embodiments, the lead layer 23 can be an FPC (Flexible Printed Circuit) board, one end of which is soldered to the conductive sheet 213 and the other end is connected to the Wheatstone bridge circuit on the PCB (Printed Circuit Board).

[0115] In some embodiments, the material of the conductive sheet 213 includes one or more of Au, silver, and copper.

[0116] In some embodiments, the thickness of the conductive sheet 213 is 500 nm to 4 μm;

[0117] In some embodiments, the second insulating layer 214 and / or the third insulating layer 215 are single-layer or multi-layer structures. The material of the single-layer structure of the second insulating layer 214 and / or the third insulating layer 215 is selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide, and YSZ. In the multi-layer structure of the second insulating layer 214 and / or the third insulating layer 215, the material of each layer is independently selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide, and YSZ.

[0118] In some embodiments, the thicknesses of the second insulating layer 214 and the third insulating layer 215 are each independently 3 to 6 μm.

[0119] Some embodiments of this application provide a method for fabricating a pad-type sensor, including:

[0120] S1) A groove S is formed on the pressure-bearing surface 1a of the gasket body 1;

[0121] S2) A pressure-sensitive layer 21 of a thin-film sensor 2 is prepared in the groove S, such that the thickness direction of the pressure-sensitive layer 21 is the same as the thickness direction of the gasket body 1, and the height difference between the pressure-bearing surface 1a of the gasket body 1 and the outer surface of the pressure-sensitive layer 21 is greater than or equal to 0 and less than or equal to 0.1 μm. The thin-film sensor 2 is used to detect the pressure on the gasket body 1 according to the electrical signal output by the pressure-sensitive layer 21.

[0122] In some embodiments, the gasket body 1 is conductive; a groove S is formed on the pressure-bearing surface 1a of the gasket body 1, including:

[0123] The groove S is etched on the pressure-bearing surface of the gasket body 1 using an electrolytic method.

[0124] In some embodiments, S1) etching grooves S on the pressure-bearing surface 1a of the gasket body 1 using an electrolytic method includes:

[0125] Using the gasket body 1 as the anode, the area of ​​the pressure-bearing surface 1a of the gasket body 1, except for the area where the groove S is located, is covered, so that the part of the pressure-bearing surface 1a of the gasket body 1 located in the area where the groove S is located undergoes an electrolytic reaction, and the groove S is etched.

[0126] In some embodiments, the gasket body 1 is used as the anode, and the area of ​​the pressure-bearing surface 1a of the gasket body 1, except for the area where the groove S is located, is covered, so that the portion of the pressure-bearing surface 1a of the gasket body 1 located in the area where the groove S is located undergoes an electrolytic reaction, and the groove S is etched. Figure 5 As shown, it includes:

[0127] S11) A mask layer 201 is prepared on the cathode 200, and the pattern of the portion of the mask layer 201 exposed on the cathode 200 is the same as the pattern of the groove S.

[0128] S12) The mask layer 201 is placed between the cathode 200 and the gasket body 1, and the cathode 200 and the gasket body 1 are fixed. The mask layer 201 exposes the part of the pressure surface of the gasket body 1 corresponding to the area where the groove S is located.

[0129] S13) Electrolyte is injected into the region between the cathode 200 and the gasket body 1 enclosed by the mask layer 201;

[0130] S14) Electricity is applied to the anode 100 and the cathode 200 to prepare a groove.

[0131] In these embodiments, the mask layer 201 serves to enclose the electrolyte filling area on the gasket body 1 and to insulate the gasket body 1 from the cathode 200. Thus, by applying current to the anode 100 and the cathode 200, a micro-electrolytic cell can be formed between the portion of the pressure-bearing surface of the gasket body 1 located in the groove area and the cathode 200, thereby allowing the pressure-bearing surface of the gasket body 1 to be etched using electrolysis.

[0132] Specifically, a reduction reaction occurs at the anode 100. For example, if the material of the gasket body 1 is copper, copper loses electrons to generate copper ions, which dissolve in the electrolyte, thereby forming a groove on the pressure surface of the gasket body 1.

[0133] In some embodiments, such as Figure 5 As shown, the mask layer 201 can be a photoresist layer with a certain pattern, which can be prepared by photolithography.

[0134] In some embodiments, such as Figure 5As shown, the cathode 200 may include a substrate layer 200a, a bonding transition layer 200b, an electrode body layer 200c, and a positioning layer 200d. The bonding transition layer 200b, electrode body layer 200c, and positioning layer 200d are sequentially disposed in a direction away from the substrate layer 200a. A mask layer 201 covers the positioning layer 200d and forms a pattern on the electrode body layer 200c through the positioning layer 200d. Examples of materials for the substrate layer 200a include conductive materials such as silicon, copper, and aluminum. The bonding transition layer 200b... b serves to enhance the adhesion between the electrode body layer 200c and the base layer 200a, and the bonding transition layer 200b has a conductive function, facilitating the transmission of current applied to the base layer 200a to the electrode body layer 200c. The material of the bonding transition layer 200b may include one or more of Cr, Ni and titanium. The positioning layer 200d can be obtained by etching, exposing the portion of the electrode body layer 200c corresponding to the groove area. The material of the positioning layer 200d may include one or more of Cr, Ni and titanium.

[0135] In some embodiments, the method for preparing the cathode 200 may include the following steps:

[0136] Step 1) Preparation of the substrate layer 200a:

[0137] The substrate 200a was polished sequentially using 800, 1000, and 1200 grit sandpaper, followed by polishing with a mixed diamond / silica spray polishing compound and polishing cloth. Next, the treated substrate 200a was ultrasonically cleaned in acetone, isopropanol, and anhydrous ethanol for approximately 10 minutes, rinsed with deionized water, and dried to obtain a clean substrate 200a.

[0138] To improve the adhesion between the substrate 200a and subsequent thin films, a plasma cleaner can be used to clean the substrate 200a, thereby increasing its surface activity. Specifically, the plasma cleaner pressure can be reduced to below 10 Pa, and then oxygen, hydrogen, nitrogen, or argon gas can be introduced to maintain the pressure below 100 Pa. The cleaning time can be from tens of seconds to several minutes, and the radio frequency can be 13.56 MHz.

[0139] Step 2) Sequentially forming an adhesive transition layer 200b, an electrode body layer 200c, and a positioning layer 200c on the substrate layer 200a, such as... Figure 5 As shown, it includes:

[0140] S101) The bonding transition layer 200b and the electrode body layer 200c are sequentially grown on the surface of the substrate layer 200a by magnetron sputtering.

[0141] S102) A positioning layer 200d is formed on the electrode body layer 200c.

[0142] The positioning layer 200d can be prepared by coating and etching processes.

[0143] Specifically, in S102a), a photoresist layer 110 can be formed on the electrode body layer 200c first, and the photoresist layer 110 can be patterned by photolithography. The patterned photoresist layer 110 and the pattern of the positioning layer 200d are complementary on the substrate layer 200a, that is, the patterned photoresist layer 110 covers the remaining areas of the substrate layer 200a except for the area where the positioning layer 200d is located.

[0144] S102b) A positioning layer film 120 is formed on the patterned photoresist layer 110, and the positioning layer film 120 covers the entire layer;

[0145] (S102c) By peeling off the patterned photoresist layer 110, the portion of the positioning layer film 120 located on the patterned photoresist layer 110 can be removed, while the portion of the positioning layer film 120 located in the area other than the area where the patterned photoresist layer 110 is located is retained, thereby obtaining the positioning layer 200d.

[0146] In some embodiments, after the cathode 200 is prepared as described above, in step S11), a mask layer 201 is prepared on the cathode 200. If the material of the mask layer 201 is photoresist, such as... Figure 5 As shown, it may include:

[0147] A photoresist layer is grown on the positioning layer 200d, and the photoresist layer is photolithographically etched to prepare the mask layer 201.

[0148] After the mask layer 201 is prepared, it can be placed between the cathode 200 and the gasket body 1, and the cathode 200 and the gasket body 1 can be fixed. Specifically, this can include:

[0149] Step 1) Polish and clean the gasket body 1. For specific steps, please refer to the above description of polishing and cleaning the base layer 200a, which will not be repeated here.

[0150] Step 2) Place the cleaned gasket body 1 with the pressure-bearing surface facing upwards, invert the cathode, and support the cathode on the pressure-bearing surface of the gasket body 1 through the mask layer 201, and use a clamp to fix the gasket body 1 and the cathode 200.

[0151] Step 3) Inject electrolyte into the space enclosed by the mask layer 201. The electrolyte fills the space between the electrode body layer 200c of the cathode 200 and the pressure-bearing surface of the gasket body 1.

[0152] Step 4) By applying current to the anode 100 and the cathode 200, an electrolytic reaction can be carried out on the pressure-bearing surface of the gasket body 1, thereby etching a groove.

[0153] In some embodiments, the electrolyte comprises: an aqueous solution of NaNO3 and / or NaClO3;

[0154] And / or,

[0155] The concentration of the electrolyte is 0.03–0.1 M;

[0156] And / or,

[0157] The current density of the above-mentioned energized circuit is 10–500 A / m 2 ;

[0158] And / or,

[0159] The power supply used in the above-mentioned power supply is a pulse power supply with a power of 0.5 to 2W, a frequency of 10 to 500Hz, and a duty cycle of 5% to 50%.

[0160] In these embodiments, the groove S can be etched. The depth and width of the groove after electrolysis can be measured by a three-dimensional profilometer. The electrolytic etching parameters are determined according to the required dimensions. After electrolysis, the groove on the pad body is rinsed with deionized water and wiped with ethanol before drying.

[0161] In some embodiments, S2), the piezoelectric sensing layer 21 of the thin-film sensor 2 is prepared in the groove S, including:

[0162] The thin films contained in the pressure transducer layer 21 are prepared by deposition and patterning processes, so that the surface of the pressure transducer layer 21 away from the groove S is higher than the pressure-bearing surface of the pad body 1 by a predetermined height.

[0163] The surface of the pressure transducer layer 21 is polished so that the height difference between the surface of the pressure transducer layer 21 away from the groove and the pressure-bearing surface of the gasket body 1 is greater than or equal to 0 and less than or equal to 0.1 μm.

[0164] Optionally, the preset height is 1 to 100 μm.

[0165] In these embodiments, by making the surface of the pressure sensing layer 21 away from the groove S higher than the pressure-bearing surface 1a of the gasket body 1 by a predetermined height, and by polishing, the surface of the pressure sensing layer 21 away from the groove S can be made closer to flush with the pressure-bearing surface 1a of the gasket body 1. Therefore, the uniformity of force on the pressure sensing layer 21 can be improved, and the wear problem caused by too many protrusions can be reduced.

[0166] In some embodiments, the deposition described above may include chemical vapor deposition and / or physical vapor deposition. The patterning process may include photolithography and / or mask fabrication.

[0167] In some embodiments, taking the above-mentioned voltage-transfer sensing layer as including a voltage-transfer resistor layer and a first insulating layer as an example, the voltage-transfer resistor layer can be prepared into a thin film by magnetron sputtering process, and then a first pattern can be prepared by photolithography process to obtain the voltage-transfer resistor layer; the first insulating layer can be prepared by magnetron sputtering process by masking with a mask.

[0168] In some embodiments, the voltage transformer sensing layer further includes a lead layer and a conductive sheet. The lead layer can be an FPC. One end of the FPC is fixed to the conductive sheet by means of soldering, conductive silver paste bonding, etc., and an organic protective adhesive such as epoxy resin is coated and compacted at the FPC. The other end is connected to a PCB board. Taking two voltage transformer sensing layers as an example, a Wheatstone bridge circuit is printed on the PCB board. The circuit includes 6 resistors with fixed resistance values. The resistance value of every 3 resistors is the same as the resistance value of a voltage transformer resistor layer. The voltage transformer resistor layer and the 3 resistors with the same resistance value on the PCB board are connected to form a Wheatstone circuit.

[0169] In some embodiments, after the voltage transformer sensing layer 21 includes a second insulating layer and a third insulating layer, the voltage transformer sensing layer 21 is raised by 1 to 100 μm above the pressure-bearing surface of the gasket body 1. After the lead wire layer is led out, the protruding part on the surface is polished flat by grinding wheel, polishing machine, etc., so that the upper surface of the voltage transformer sensing layer 21 is flush with the pressure-bearing surface of the gasket body 1.

[0170] After preparing the second and third insulating layers, the entire gasket body is placed in an annealing furnace and annealed in an argon atmosphere at a temperature of 300–500°C for 1–2 hours.

[0171] In these embodiments, annealing can stabilize the resistance change error of the voltage transformer layer after being subjected to temperature and pressure, and make the microstructure of the insulating layer material denser and improve its toughness, thereby reducing the possibility of the insulating layer cracking and falling off.

[0172] Thirdly, some embodiments of this application provide an application of the gasket-type sensor as described above in bolt preload sensing.

[0173] like Figure 2As shown, when the bolt 30 is screwed into the nut 20, the gasket body 1 is squeezed. Due to the piezoresistive effect, the resistance of the voltage transformer sensing layer changes, which in turn causes the bridge voltage of the Wheatstone bridge in the PCB board to change. The change in voltage is related to the preload. By calibrating this relationship, the magnitude of the preload can be obtained based on the output voltage of the bridge circuit, thus realizing the online measurement of the bolt preload.

[0174] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0175] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A pad-type sensor, characterized in that, include: The gasket body has a groove on its pressure-bearing surface; A thin-film sensor, comprising: a pressure-sensitive layer disposed within the groove, wherein the thickness direction of the pressure-sensitive layer is the same as the thickness direction of the gasket body; Wherein, the height difference between the surface of the pressure-sensitive layer away from the bottom of the groove and the pressure-bearing surface of the gasket body is greater than or equal to 0 and less than or equal to 0.1 μm; the thin-film sensor is used to detect the pressure on the gasket body based on the electrical signal output by the pressure-sensitive layer; The pressure-sensitive layer includes a pressure-sensitive resistor layer, which is disposed on the bottom surface of the groove; The thin-film sensor further includes: a measurement circuit and a lead layer electrically connected to the piezoelectric resistive layer. The lead layer is used to connect the electrical signal output by the piezoelectric resistive layer to the measurement circuit. The thin-film sensor detects the pressure on the gasket body through the measurement circuit. The lead layer is disposed on the side of the varistor layer away from the bottom surface of the groove, and is electrically connected to the varistor layer through a conductive sheet disposed between the lead layer and the varistor layer; The voltage transformer induction layer further includes: a second insulating layer and a third insulating layer disposed between the voltage transformer resistor layer and the lead layer; The second insulating layer has through holes for connecting the conductive sheet and the lead layer, and the second insulating layer is arranged around the conductive sheet. The third insulating layer covers the remaining area of ​​the voltage transformer induction layer except for the area where the conductive sheet and the second insulating layer are located.

2. The pad-type sensor according to claim 1, characterized in that, The surface of the pressure-sensitive layer away from the bottom of the groove is flush with the pressure-bearing surface of the gasket body; And / or, The depth of the groove is 10~50μm.

3. The pad-type sensor according to claim 1 or 2, characterized in that, The shape enclosed by the voltage transformer layer and the bottom edge of the groove is the same.

4. The pad-type sensor according to claim 3, characterized in that, The groove extends in a meandering manner on the gasket body; The voltage-changing resistor layer has a first pattern, which extends in a meandering manner on the bottom surface of the groove; And / or, The voltage-changing resistor layer can be a single-layer structure or a multi-layer structure. The single-layer structure of the voltage-changing resistor layer includes any one of Ti metal thin film, manganese copper alloy thin film, nickel carbon alloy thin film, silicon carbide thin film and graphene-metal composite thin film. In the multi-layer structure of the voltage-changing resistor layer, each layer is independently selected from any one of Ti metal thin film, manganese copper alloy thin film, nickel carbon alloy thin film, silicon carbide thin film and graphene-metal composite thin film. And / or, The thickness of the voltage-varistor layer is 400~800nm; And / or, The voltage-changing resistor layer is in the shape of strips, the length of which is 1.5~2mm and the width of which is 50~200μm.

5. The pad-type sensor according to claim 3, characterized in that, The gasket body is conductive; The voltage transformer sensing layer further includes: a first insulating layer, wherein the first insulating layer is disposed on the side of the voltage transformer resistive layer near the bottom surface of the groove, and the first insulating layer covers the bottom surface and side surface of the groove; Optionally, the material of the gasket body includes one or more of doped silicon and metallic materials; Optionally, the material of the gasket body includes one or more of aluminum and copper.

6. The pad-type sensor according to claim 5, characterized in that, The first insulating layer is a single-layer structure or a multi-layer structure. The material of the single-layer structure of the first insulating layer is selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ. In the multi-layer structure of the first insulating layer, the material of each layer is independently selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ. And / or, The thickness of the first insulating layer is 3~6μm.

7. The pad-type sensor according to claim 1, characterized in that, The measurement circuit is a Wheatstone bridge circuit, and the voltage transformer layer is connected in the Wheatstone bridge circuit as the measuring resistor.

8. The pad-type sensor according to claim 1, characterized in that, The conductive sheet is made of one or more of Au, silver, and copper. And / or, The thickness of the conductive sheet is 500 nm to 4 μm; And / or, The second insulating layer and / or the third insulating layer are single-layer or multi-layer structures. The material of the single-layer structure of the second insulating layer and / or the third insulating layer is selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ. In the multi-layer structure of the second insulating layer and / or the third insulating layer, the material of each layer is independently selected from one or more of Cr, Ni, Ti, silicon nitride, aluminum oxide, silicon oxide and YSZ. And / or, The thicknesses of the second insulating layer and the third insulating layer are each 3~6μm.

9. The pad-type sensor according to claim 1, characterized in that, The gasket body is annular and sheet-shaped, and the pressure-bearing surface is at least one of two surfaces of the sheet that are arranged opposite each other along its thickness direction. There are two grooves and two pressure-sensitive layers, respectively, which are disposed on opposite sides of the gasket body along its center.

10. A method for manufacturing a pad-type sensor, characterized in that, include: A groove is made on the pressure-bearing surface of the gasket body; A pressure-sensitive layer for a thin-film sensor is prepared in the groove, such that the thickness direction of the pressure-sensitive layer is the same as the thickness direction of the gasket body, and the height difference between the pressure-bearing surface of the gasket body and the outer surface of the pressure-sensitive layer is greater than or equal to 0 and less than or equal to 0.1 μm. The thin-film sensor is used to detect the pressure on the gasket body based on the electrical signal output by the pressure-sensitive layer. The method of creating a groove on the pressure-bearing surface of the gasket body includes: using the gasket body as an anode; A mask layer is prepared on the cathode, wherein the pattern of the exposed portion of the mask layer is the same as the pattern of the groove; The mask layer is placed between the cathode and the gasket body, and the anode and the gasket body are fixed. The portion of the mask layer that exposes the pressure surface of the gasket body corresponding to the area where the groove is located is the part of the groove. Electrolyte is injected into the region between the cathode and the gasket body enclosed by the mask layer; The groove is fabricated by applying current to the anode and cathode. The pressure-sensitive layer includes a pressure-sensitive resistor layer, which is disposed on the bottom surface of the groove; The thin-film sensor further includes: a measurement circuit and a lead layer electrically connected to the piezoelectric resistive layer. The lead layer is used to connect the electrical signal output by the piezoelectric resistive layer to the measurement circuit. The thin-film sensor detects the pressure on the gasket body through the measurement circuit. The lead layer is disposed on the side of the varistor layer away from the bottom surface of the groove, and is electrically connected to the varistor layer through a conductive sheet disposed between the lead layer and the varistor layer; The voltage transformer induction layer further includes: a second insulating layer and a third insulating layer disposed between the voltage transformer resistor layer and the lead layer; The second insulating layer has through holes for connecting the conductive sheet and the lead layer, and the second insulating layer is arranged around the conductive sheet. The third insulating layer covers the remaining area of ​​the voltage transformer induction layer except for the area where the conductive sheet and the second insulating layer are located.

11. The preparation method according to claim 10, characterized in that, The gasket body is conductive.

12. The preparation method according to claim 10, characterized in that, The electrolyte includes: an aqueous solution of NaNO3 and / or NaClO3; And / or, The concentration of the electrolyte is 0.03~0.1M; And / or, The current density of the energized circuit is 10~500A / m 2 ; And / or, The power supply used for the power-on is a pulse power supply with a power of 0.5~2W; the frequency of the pulse power supply is 10~500Hz and the duty cycle is 5%~50%.

13. The preparation method according to any one of claims 10 to 12, characterized in that, Fabricating a pressure-sensitive layer for a thin-film sensor within the groove includes: The thin films comprising the pressure-sensitive layer are prepared by deposition and patterning processes, such that the surface of the pressure-sensitive layer away from the groove is higher than the pressure-bearing surface of the gasket body by a predetermined height; The surface of the pressure transducer layer is polished so that the height difference between the surface of the pressure transducer layer away from the groove and the pressure-bearing surface of the gasket body is less than 0.1 μm; Optionally, the preset height is 1~100μm.

14. The application of a gasket-type sensor as described in any one of claims 1 to 9 in bolt preload sensing.

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