Weighing sensor

Abstract

The utility model discloses a weighing sensor, which relates to the technical field of weighing sensors and comprises a metal foil layer, a bonding layer and an elastic body. Sensitive grids are formed on the metal foil layers, and the number of the metal foil layers is two; the number of the bonding layers is two; the two bonding layers are connected with the two sides of the elastic body respectively, the two metal foil layers are connected with the sides, away from the elastic body, of the two bonding layers respectively, and the two sensitive grids are connected through a wire. Sensitive grids are processed and formed on two metal foil layers, then the metal foil layers and an elastic body are bonded through a bonding layer, and then the two sensitive grids are connected through a wire, so that the manufacturing of the weighing sensor is completed, and the whole weighing sensor only has a three-layer structure; the loss of stress transmission is effectively reduced, and the strain coefficient is improved, so that the measurement accuracy is improved, and the measurement error is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of weighing sensors, in particular to a weighing sensor. Background Art

[0002] At present, the manufacturing principle of weighing sensors is to paste the finished product of conventional strain gauges on the elastic body, then form an electric bridge, and perform testing, compensation and protection. In this conventional method of making weighing sensors, a layer of patch glue is applied between the elastomer and the strain gauge. In this way, after the strain gauge is pasted, a five-layer strain test structure is formed, which is: patch glue, substrate, adhesive, foil, and cover film from the elastic body to the outside.

[0003] The strain of a conventional weighing sensor is generated on the surface of the elastomer after being loaded, and is transferred to the substrate through the patch glue, the substrate to the adhesive, and the adhesive to the sensitive grid, forming a strain gauge transmission layer. The strain is measured by the change in the resistance of the sensitive grid and the voltage change of the Wheatstone bridge composed of the sensitive grid, thereby achieving weighing measurement. However, the elastic modulus of the substrate, adhesive and sensitive grid materials are quite different, which will cause deformation errors in the transmission process, resulting in large measurement errors.

[0004] Therefore, it is necessary to provide a new weighing sensor to solve the above technical problems. Utility Model Content

[0005] The main purpose of the utility model is to provide a weighing sensor, aiming to improve the technical problem of large measurement error of weighing sensors in the prior art.

[0006] To achieve the above-mentioned purpose, the weighing sensor proposed by the utility model comprises:

[0007] A metal foil layer, on which a sensitive grid is formed, and the number of the metal foil layers is two;

[0008] Adhesive layers, the number of the adhesive layers is two;

[0009] The two adhesive layers are respectively connected to two sides of the elastic body, the two metal foil layers are respectively connected to one side of the two adhesive layers away from the elastic body, and the two sensitive grids are connected through wires.

[0010] In one embodiment, the bonding layer includes an insulating sublayer and an adhesive sublayer connected to each other, the insulating sublayer is connected to the elastomer on one side facing away from the adhesive sublayer, and the adhesive sublayer is connected to the metal foil layer on one side facing away from the sensitive grid on one side facing away from the insulating sublayer.

[0011] In one embodiment, the metal foil layer is a constantan alloy layer.

[0012] In one embodiment, the thickness of the metal foil layer is in a range of 3 μm to 5 μm.

[0013] In one embodiment, a frosted surface is formed on the surface of the elastic body.

[0014] In one embodiment, the area of ​​the insulating sublayer is greater than the area of ​​the metal foil layer.

[0015] In one embodiment, the size of the metal foil layer is 2 to 3 times the size of the sensitive grid.

[0016] In one embodiment, the surfaces of the sensitive grids are coated with a protective layer.

[0017] In one embodiment, the thickness of the protective layer ranges from 1 mm to 3 mm.

[0018] The utility model also proposes a method for manufacturing a weighing sensor, which is applied to the weighing sensor as described above, and comprises the following steps:

[0019] After the elastomer is heat-treated, the surface of the heat-treated elastomer is sandblasted; the metal foil layer is vacuum heat-treated, the heat-treated metal foil layer is cut, and the oxide layer on the surface of the vacuum heat-treated metal foil layer is removed;

[0020] Coating insulating sublayers on both sides of the elastomer, coating an adhesive sublayer on the side of the insulating sublayer facing away from the elastomer, adhering the two metal foil layers to the two adhesive sublayers and curing them, processing a sensitive grid on the side of the metal foil layer facing away from the adhesive sublayer, and adjusting the resistance value of the sensitive grid;

[0021] Coating the surface of the sensitive grid to form a protective layer;

[0022] The sensitive grids are connected through wires to form a Wheatstone bridge to form the weighing sensor.

[0023] In the above scheme, the weighing sensor includes a metal foil layer, an adhesive layer and an elastomer; a sensitive grid is formed on the metal foil layer, and the number of the metal foil layers is two; the number of the adhesive layers is two; the two adhesive layers are respectively connected to the two sides of the elastomer, the two metal foil layers are respectively connected to the side of the two adhesive layers away from the elastomer, and the two sensitive grids are connected by wires. The weighing sensor in the prior art is made of a five-layer structure of patch glue, substrate, adhesive layer, foil and cover film; while the weighing sensor in the technical solution of the utility model no longer uses a finished strain gauge, but adopts a sensitive grid formed by processing two metal foil layers, and then the metal foil layer and the elastomer are bonded through an adhesive layer, and then the two sensitive grids are connected through a wire, so that the weighing sensor is completed, and the entire weighing sensor has only a three-layer structure; when the weighing sensor is used, the strain of the elastomer is transmitted to the sensitive grid by the adhesive layer, so that the strain of the elastomer only needs to be transmitted through one adhesive layer, thus avoiding the influence of strain transmission caused by different expansion coefficients of the substrate, cover film and patch glue in the prior art and the temperature influence caused by temperature changes, effectively reducing the loss of stress transmission, and improving the strain coefficient, thereby improving the measurement accuracy and greatly reducing the measurement error. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0025] Figure 1 A structural schematic diagram of a weighing sensor provided by the utility model when the sensitive grid is not connected in one embodiment from one viewing angle;

[0026] Figure 2 It is a structural schematic diagram of another perspective of an embodiment of the weighing sensor provided by the utility model when the sensitive grid is not connected;

[0027] Figure 3 A structural schematic diagram of a weighing sensor according to an embodiment of the present invention from one perspective;

[0028] Figure 4 A structural schematic diagram of another perspective of an embodiment of a weighing sensor provided by the utility model;

[0029] Figure 5 A cross-sectional view of an embodiment of a weighing sensor provided by the utility model;

[0030] Figure 6 This is a schematic diagram of an embodiment of a sensitive gate provided by the utility model.

[0031] Description of Figure Numbers:

[0032] 100. Weighing sensor; 1. Metal foil layer; 2. Adhesive layer; 3. Elastomer; 11. First sensitive grid; 21. Insulator layer; 22. Adhesive layer.

[0033] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0035] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0036] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0037] The strain of a conventional weighing sensor is generated on the surface of the elastomer 3 after being loaded, and is transferred to the substrate through the patch glue, the substrate transfers it to the adhesive, and the adhesive transfers it to the sensitive grid, forming a strain gauge transmission layer. The strain is measured by the change in the resistance of the sensitive grid and the voltage change of the Wheatstone bridge composed of the sensitive grid, thereby realizing weighing measurement. However, the elastic modulus of the substrate, adhesive and sensitive grid materials are quite different, which will cause deformation errors in the transmission process, resulting in large measurement errors.

[0038] See also Figures 1 to 6 The utility model proposes a weighing sensor 100, comprising a metal foil layer 1, an adhesive layer 2 and an elastomer 3; a sensitive grid 11 is formed on the metal foil layer 1, and the number of the metal foil layers 1 is two; the number of the adhesive layers 2 is two; the two adhesive layers 2 are respectively connected to the two sides of the elastomer 3, the two metal foil layers 1 are respectively connected to the side of the two adhesive layers 2 away from the elastomer 3, and the two sensitive grids 11 are connected by wires. The weighing sensor 100 in the prior art is made of a five-layer structure of patch glue, substrate, adhesive layer, foil and cover film; while in the technical solution of the utility model, the weighing sensor 100 no longer uses a finished strain gauge, but uses two metal foil layers 1 to form a sensitive grid 11, and then the metal foil layer 1 and the elastomer 3 are bonded through the adhesive layer 2, and then the two sensitive grids 11 are connected through a wire, so that the weighing sensor 100 is completed. The entire weighing sensor 100 has only a three-layer structure; when the weighing sensor 100 is used, the strain of the elastomer 3 is transmitted to the sensitive grid 11 by the adhesive layer 2, so that the strain of the elastomer 3 only needs to be transmitted through one layer of adhesive layer 2, thus avoiding the influence of strain transmission caused by different expansion coefficients of the substrate, cover film and patch glue in the prior art and the temperature influence caused by temperature changes, effectively reducing the loss of stress transmission, improving the strain coefficient, thereby improving the measurement accuracy, and greatly reducing the measurement error.

[0039] Specifically, the relationship between the sensitivity coefficient K of the weighing sensor 100 and the sensitivity of the sensitive grid material can be expressed by the following formula:

[0040] K=K 0 / {1+4h / Z×h×A / L(1+u b )×E o / E h}

[0041] h is the total thickness of the substrate, adhesive and patch adhesive layer; Z is the effective width of the transition zone; b is the effective length of the transition zone; A is the wire grid cross-sectional area of ​​the sensitive grid; L is the grid length of the sensitive grid; ub is the Poisson's ratio of the substrate and the adhesive layer; Eo is the elastic modulus of the substrate and the adhesive layer; Eh is the elastic modulus of the sensitive grid;

[0042] It can be seen from the above formula that the total thickness of the substrate and the adhesive, the Poisson's ratio of the substrate and the adhesive layer, and the elastic modulus of the substrate and the adhesive layer affect the sensitivity coefficient of the resistance strain gauge of the strain gauge, and thus affect the strain transfer. Therefore, reducing the number of transfer layers between the sensitive grid and the elastomer 3 is beneficial to the stability of the weighing sensor 100 and the accuracy of strain measurement, and improves the temperature and creep stability of the weighing sensor 100.

[0043] Furthermore, in the prior art, the adhesive between the metal foil layer 1 and the substrate and the patch glue of the strain gauge are both polymer materials, and the adhesive in the strain gauge and the patch glue layer used when sticking the strain gauge have a certain thickness. The above errors are all differences caused by the patch, which will lead to large deviations and large discreteness in the zero temperature performance, sensitivity temperature performance, creep and creep recovery performance of the sensor. In this application, the sensitive grid is directly processed on the elastomer 3, which reduces the number of layers of the patch and the number of layers of the weighing sensor 100, which greatly improves the zero temperature performance, sensitivity temperature performance, creep and creep recovery performance of the weighing sensor 100, thereby reducing deviations and reducing discreteness.

[0044] See also Figures 1 to 6 In one embodiment, the bonding layer 2 includes an insulating sublayer 21 and an adhesive sublayer 22 connected to each other. The side of the insulating sublayer 21 facing away from the adhesive sublayer 22 is connected to the elastomer 3, and the side of the adhesive sublayer 22 facing away from the insulating sublayer 21 is connected to the side of the metal foil layer 1 facing away from the sensitive grid 11. Specifically, the epoxy adhesive is scraped on both sides of the elastomer 3 by a scraper to form the insulating sublayer 21, and the thickness of the insulating sublayer 21 is generally 3μm, and then dried; generally speaking, the area of ​​the insulating sublayer 21 is larger than the area of ​​the metal foil layer 1; then a thin layer of adhesive is brushed on the dried insulating sublayer 21 to form the adhesive sublayer 22, the metal foil layer 1 is covered on the adhesive sublayer 22, and the bubbles in the metal foil layer 1 are squeezed out. After the metal foil layer 1 is pasted on the adhesive sublayer 22, it is pressurized for the first curing. The method of the first curing is to cover the metal foil layer 1 with a silicone rubber plate, and pad a polytetrafluoroethylene film between the silicone rubber plate and the metal foil layer 1. The area of ​​the polytetrafluoroethylene film pad is larger than the area of ​​the metal foil layer 1 and the silicone rubber. A stainless steel plate is pad on the silicone rubber plate, and a pressure of 3MPa is applied to the stainless steel pad. The temperature is set at 125°C and kept warm for 4 hours. After the first curing is completed, the pressure of the elastomer 3 that has been cured for the first time is removed, and the second curing is carried out in a curing furnace. The temperature is set at 186°C and kept warm for 2 hours. The above-mentioned setting can insulate the metal foil layer 1 and the elastomer 3, ensure the normal operation of the weighing sensor 100, and at the same time increase the service life and accuracy of the weighing sensor 100.

[0045] In one embodiment, the metal foil layer 1 is a constantan alloy layer. Constantan alloy has a low temperature coefficient of resistance, a wide operating temperature range (below 480°C), good mechanical processing performance, high corrosion resistance and easy brazing, and can be used for a long time in harsh environments such as the ocean. Constantan alloy has good corrosion resistance and high temperature performance, and can maintain stable performance during long-term use. The strength of constantan alloy is higher than that of pure copper and many other copper alloys, and has extremely high tensile strength and yield strength. At the same time, constantan alloy has similar electrical conductivity to pure copper, which is superior to many other strength materials.

[0046] In one embodiment, the thickness of the metal foil layer 1 is in the range of 3 μm to 5 μm. The thickness of the metal foil layer 1 has different requirements for different measurements, but the greater the thickness of the metal foil layer 1, the lower the accuracy, and the smaller the thickness, the smaller the measurement range, and the more sensitive it becomes. When the thickness of the metal foil layer 1 is in the range of 3 μm to 5 μm, it can ensure a certain accuracy within a larger range and ensure the accuracy of the measurement.

[0047] In one embodiment, frosted surfaces are formed on both sides of the elastomer 3. The surface of the elastomer 3 is treated with frosted particles, which can be of various hardness and shapes, such as round, elliptical and polygonal, etc., and can be achieved by coating or spraying the frosted particles on the surface of the elastomer 3. This surface frosting treatment can improve the aesthetics, wear resistance and oil resistance of the elastomer 3, and can increase the friction coefficient of the surface of the elastomer 3 to a certain extent, thereby improving the application range and performance of the elastomer 3; at the same time, it can improve the firmness of the bonding.

[0048] In one embodiment, the area of ​​the insulating sublayer 21 is larger than the area of ​​the metal foil layer 1. The area of ​​the insulating sublayer 21 is set larger than the metal foil layer, so that the metal foil layer 1 can be completely insulated from the elastic body 3, further ensuring the normal operation of the weighing sensor 100, and further increasing the service life and accuracy of the weighing sensor 100.

[0049] In one embodiment, the size of the metal foil layer 1 is 2 to 3 times the size of the sensitive grid 11. Setting the size of the metal foil layer 1 to 2 to 3 times the size of the sensitive grid 11 will improve the heat dissipation condition of the sensitive grid 11, allow a larger current to pass, improve the sensitivity, and increase the power of the output signal. According to the required size of the sensitive grid 11, a metal foil layer with a size 2 to 3 times larger than the size of the sensitive grid 11 is selected, so that there will be enough margin during processing to ensure the normal processing of the sensitive grid 11.

[0050] In one embodiment, a protective layer is coated on the surface of the sensitive grid 11. Specifically, the protective layer can protect the sensitive grid 11 from damage, greatly increasing the service life of the weighing sensor 100. Generally, the protective layer is made of materials such as silicone, polyurethane and isobutyl rubber.

[0051] In one embodiment, the thickness of the protective layer ranges from 1 mm to 3 mm. Specifically, in order to improve the protective ability of the protective layer, the protective layer needs to have a certain thickness, but too thick a thickness will affect the accuracy of the weighing sensor 100. When the thickness of the protective layer ranges from 1 mm to 3 mm, the protective ability of the protective layer can be improved without seriously affecting the accuracy of the weighing sensor 100.

[0052] In one embodiment, the thickness of the adhesive layer 2 is in the range of 1 μm to 3 μm. The thickness of the adhesive layer 2 is different for different measurement requirements, but the thicker the adhesive layer 2 is, the lower the accuracy will be, and the smaller the thickness is, the insulation failure between the metal foil layer 1 and the adhesive layer 2 may occur, thereby damaging the weighing sensor. When the thickness of the adhesive layer 2 is in the range of 1 μm to 3 μm, a certain accuracy is guaranteed, and at the same time, the insulation effect between the metal foil layer 1 and the adhesive layer 2 is guaranteed.

[0053] The manufacturing method of the weighing sensor comprises the following steps:

[0054] After the elastomer 3 is heat-treated, the surface of the heat-treated elastomer 3 is sandblasted; the metal foil layer 1 is vacuum heat-treated, the heat-treated metal foil layer 1 is cut, and the oxide layer on the surface of the vacuum heat-treated metal foil layer 1 is removed;

[0055] According to different use requirements and use environments, the elastomer 3 is processed and formed according to the design requirements, and the elastomer 3 is subjected to corresponding heat treatment, and the surface of the elastomer 3 is sandblasted, and the surface of the elastomer 3 is sandblasted with 100# diamond sand; the metal foil layer 1 is made of constantan alloy material, the thickness of the metal foil layer 1 is 3μm~5μm, and the area is cut into a square size of about 110mm, and a corresponding vacuum heat treatment is performed, the heating temperature is 350℃~500℃, and the vacuum degree is ≤10 -3 After the heat treatment is completed, the oxide layer generated on the surface of the heat-treated metal foil layer 1 is removed by using 6000 mesh to 8000 mesh AL 2 O 3 Mixed with pure water to form a mixed liquid, AL 2 O 3 The volume ratio of the mixture to pure water is 1:2, and then the surface of the metal foil layer 1 is wiped with the mixture until it is bright, thereby removing the oxide layer on the surface; finally, the heat-treated metal foil layer 1 is cut into the corresponding size to be produced.

[0056] An insulating sublayer 21 is coated on both sides of the elastomer 3, and an adhesive sublayer 22 is coated on the side of the insulating sublayer 21 facing away from the elastomer 3, and then two metal foil layers 1 are adhered to the adhesive sublayer 22 and cured, and a sensitive grid 11 is formed on the side of the metal foil layer 1 facing away from the adhesive sublayer 22, and the resistance value of the sensitive grid 11 is adjusted;

[0057] On the outer side of the sandblasted surface of the elastomer 3, a layer of insulating sublayer 21 is applied by scraping epoxy adhesive with a scraper, the thickness of the insulating sublayer 21 is 3 μm, and then the insulating sublayer 21 is dried, and the area of ​​the insulating sublayer 21 is larger than the area of ​​the metal foil layer 1; then a thin layer of adhesive is brushed on the surface of the dried insulating sublayer 21 to form an adhesive sublayer 22, and then the metal foil layer 1 is covered on the adhesive sublayer 22, and the bubbles in the adhesive sublayer 22 and the metal foil layer 1 are squeezed out; after completion, the first curing is carried out, and the metal foil layer 1 is covered with silicone rubber The silicone rubber plate is provided with a polytetrafluoroethylene film between the silicone rubber plate and the metal foil layer 1. The area of ​​the polytetrafluoroethylene film is larger than that of the metal foil layer 1 and the silicone rubber plate. The silicone rubber plate is covered with a stainless steel plate, and a pressure of 3MPa is applied to the stainless steel pad, and the temperature is kept at 125°C for 4 hours. After the first curing is completed, a second curing is performed to ensure the firmness of the connection between the elastomer 3 and the metal foil layer. The pressure of the elastomer 3 after the first curing is removed, and the elastomer 3 is cured in a curing furnace at a temperature of 186°C for 2 hours. After the curing is completed, the metal foil layer 1 is laser processed by laser equipment to form a sensitive grid 11. After the processing is completed, the elastomer 3 is turned over, and the sensitive grid 31 is processed on the metal foil layer 1 on the other side. After the processing is completed, according to different needs, the resistance value of the sensitive grid 11 is adjusted to the required value by mechanical resistance adjustment or chemical resistance adjustment.

[0058] Coating the surface of the sensitive grid 11 to form a protective layer;

[0059] A protective layer is coated on the surface of the sensitive grid 11. The protective layer is made of materials such as silicone, polyurethane and butyl rubber. The thickness of the protective layer is 1 mm to 3 mm.

[0060] The two sensitive grids 11 are connected by wires to form a Wheatstone bridge to form a weighing sensor 100 .

[0061] The two sensitive grids 11 with qualified adjusted resistance are connected through wires. Generally speaking, through holes are opened on the metal foil layer 1, the adhesive layer 2 and the elastomer 3, and the wires pass through the through holes. The two ends of the wires are respectively connected to the two sensitive grids 11 and connected to the circuit board. After the connection is completed, a Wheatstone bridge is formed, and the weighing sensor 100 is completed.

[0062] In the above-mentioned embodiment of the utility model, the sensitive grid 11 is directly processed on the two metal foil layers 1, so that the number of layers of the entire weighing sensor 100 is reduced. When the weighing sensor 100 is used, the deformation generated by the elastomer 3 is transmitted to the sensitive grid 11 of the metal foil layer, so that it is only transmitted through one layer of adhesive layer 2; while in the prior art, it is necessary to transmit through the patch adhesive and the substrate more. Since the strain capacity of each layer is different, errors will occur in the transmission process, resulting in large errors in the measurement results; the utility model only needs to be transmitted through one layer of adhesive layer 2, which greatly reduces the transmission error, thereby reducing the error of the measurement result, and further improving the accuracy of the weighing sensor 100.

[0063] Furthermore, after the production is completed, the weighing sensor 100 needs to be calibrated and tested. After the Wheatstone bridge is formed, the zero point of the weighing sensor 100 is measured and compensated to the range of ±1% FS; then a load of 150% FS% to 200% FS is applied to the weighing sensor 100 and repeated 5 to 10 times; temperature zero point compensation is also required, and zero point temperature compensation is performed at 20°C, -10°C, and 40°C on the zero point temperature compensation device. Zero point data is collected at the above temperature, and corresponding compensation is performed according to the result; testing and sensitivity compensation are performed, a rated load is applied to the weighing sensor 100, the sensitivity of the weighing sensor 100 is measured, and the sensitivity is compensated to the required standard range. After the measurement is completed, the surface of the weighing sensor 100 is coated for protection with a thickness of 2mm to 5mm. The coating material is a polymer material such as silicone, polyurethane and rubber, in order to prevent the insulation of the weighing sensor 100 from being affected by moisture; after the coating is completed, the various performance indicators of the design requirements of the weighing sensor 100 are tested on a standard force measuring machine, and the appearance of the weighing sensor 100 and various product and electrical performance indicators are tested to determine whether they meet the standards and determine the level; after the test is completed, the manufactured weighing sensor 100 is packaged.

[0064] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A weighing sensor, characterized in that: include: A metal foil layer, on which a sensitive grid is formed, and the number of the metal foil layers is two; Adhesive layers, the number of the adhesive layers is two; The two adhesive layers are respectively connected to two sides of the elastic body, the two metal foil layers are respectively connected to one side of the two adhesive layers away from the elastic body, and the two sensitive grids are connected through wires.

2. The weighing sensor according to claim 1, characterized in that: The bonding layer includes an insulating sublayer and an adhesive sublayer connected to each other. The side of the insulating sublayer facing away from the adhesive sublayer is connected to the elastomer, and the side of the adhesive sublayer facing away from the insulating sublayer is connected to the side of the metal foil layer facing away from the sensitive grid.

3. The weighing sensor according to claim 1, characterized in that: The metal foil layer is a constantan alloy layer.

4. The weighing sensor according to claim 1, characterized in that: The thickness of the metal foil layer is in the range of 3 μm to 5 μm.

5. The weighing sensor according to claim 1, characterized in that: The surface of the elastic body is formed with a frosted surface.

6. The weighing sensor according to claim 2, characterized in that: The area of ​​the insulating sublayer is greater than the area of ​​the metal foil layer.

7. The weighing sensor according to claim 2, characterized in that: The size of the metal foil layer is 2 to 3 times the size of the sensitive grid.

8. The weighing sensor according to claim 1, characterized in that: The surfaces of the sensitive grids are coated with a protective layer.

9. The weighing sensor according to claim 8, characterized in that: The thickness of the protective layer ranges from 1 mm to 3 mm.

10. The weighing sensor according to claim 1, characterized in that: The thickness of the adhesive layer ranges from 1 mm to 3 mm.

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