Weighing sensor based on conductive carbon fiber

Abstract

The utility model discloses a weighing sensor based on conductive carbon fiber, which comprises a weighing beam, conductive silver adhesive, strain resistance wire grids and a connecting lead, four groups of strain resistance wire grids are symmetrically arranged on the weighing beam, each group comprises at least two strain resistance wire grids which are electrically connected with each other through the conductive silver adhesive, and the connecting lead is connected with the weighing beam through the conductive silver adhesive. The conductive silver adhesive is further arranged at the two ends of each strain resistance wire grid to form two connecting points, one end of the connecting wire is fixedly connected with the connecting points, and the other end of the connecting wire is welded to a bonding pad of the wiring terminal to form a measuring bridge. The strain resistance wire grids are connected through the conductive silver adhesive, transmission stability of electric signals is guaranteed, good conductivity and adhesion performance are achieved, resistance can be effectively reduced, and sensitivity and response speed of the sensor are improved. And in combination with efficient environmental protection measures, the sensor has good stability and precision and long service life.

Description

Technical Field

[0001] This utility model belongs to the field of weighing sensor technology, specifically relating to a weighing sensor based on conductive carbon fiber. Background Technology

[0002] A load cell is essentially a device that converts a mass signal into a measurable electrical signal output. When using a load cell, the actual working environment must be considered first. This is crucial for the correct selection of a load cell, as it relates to the load cell's normal operation, safety, lifespan, and even the overall reliability and safety of the weighing instrument. There are significant differences between the old and new national standards regarding the basic concepts and evaluation methods for the main technical indicators of load cells. The main types include S-type, cantilever type, spoke type, plate ring type, diaphragm type, bridge type, and column type.

[0003] With the continuous development of intelligent technologies, the market demand for accurate, sensitive, and low-cost sensors is increasing. Existing weighing sensors typically use strain gauges or piezoelectric materials, but these technologies suffer from high costs or complexity. In recent years, flexible electronics technology based on conductive inks has emerged as a new research direction, enabling the development of high-performance sensors through simple manufacturing processes.

[0004] Utilizing the electrical conductivity and resistance-strain characteristics of carbon materials, inks are first prepared by mixing them with other solvents. Then, various force sensors can be manufactured through printing and other processes. For example, existing technologies such as patents "CN110105813A - A carbon-based conductive ink, its preparation method and application", "CN 117804326A - Preparation and application of an embedded carbon nanocomposite flexible piezoresistive sensor", and "CN 118516012 A - A sensitive ink for high-sensitivity strain gauges, a sensitive ink-printed strain gauge and its preparation method" all describe the manufacturing methods of inks and their applications in force measurement.

[0005] However, these force sensors based on carbon conductive ink have a drawback: the sensor output signal has high noise, is sensitive to temperature, is easily affected by the external environment, and the output signal is unstable. Although it can be supplemented by some temperature or zero-point compensation methods, it often depends on the linkage control between external temperature-sensitive components and the sensor signal. These methods often increase cost, complexity, or size.

[0006] From a microscopic perspective, the signal noise of conductive ink sensors based on carbon materials (such as carbon nanotubes, graphene, and graphite) mainly originates from the physical properties of the carbon materials themselves and their behavioral changes within composite materials. These changes lead to variations in the resistivity, electron mobility, and microstructure of the composite materials, thereby increasing the sensor's sensitivity. Therefore, improving the behavioral characteristics of these carbon materials within composite materials is one of the technical approaches to enhancing the stability of the output signal of carbon-based material sensors. Utility Model Content

[0007] The purpose of this invention is to provide a weighing sensor based on conductive carbon fiber. The technical problem to be solved is that in the prior art, the metal material below or around the strain gauge of the weighing carbon fiber is too thick, resulting in poor sintering effect in the center of the slurry.

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] In a first aspect, this utility model provides a weighing sensor based on conductive carbon fiber, including a weighing beam, conductive silver paste, strain gauge wire grids, and connecting wires. The strain gauge wire grids are arranged symmetrically in four groups on the weighing beam, and each group has at least two strain gauge wire grids that are electrically connected to each other through conductive silver paste. The conductive silver paste is also provided at both ends of each group of strain gauge wire grids to form two connection points. One end of the connecting wire is connected and fixed to the connection point, and the other end is soldered to the pad of the terminal block to form a measuring bridge.

[0010] By connecting the strain gauge wire grid with conductive silver paste, the stability of electrical signal transmission is ensured. It also has good conductivity and adhesion properties, which can effectively reduce resistance and improve the sensitivity and response speed of the sensor. Through the innovative design of the strain gauge wire grid and the bridge connection scheme, combined with efficient environmental protection measures, the sensor has good stability, accuracy and service life.

[0011] Optionally, the strain gauge wire grid consists of four resistive elements G1 to G4, connected in the form of a Wheatstone bridge. The Wheatstone bridge formed by the strain gauge wire grid ensures the accurate transmission and measurement of electrical signals.

[0012] Optionally, the mounting surface of the weighing beam is also coated with glass glue, and the strain gauge wire grid is set on the glass glue by screen printing. The glass glue has good insulation and adhesion, which can effectively fix the strain gauge wire grid, and also play a role in insulation and moisture protection.

[0013] Optionally, the surface of the weighing beam is coated with a silicone rubber protective layer, which is uniformly covered on the strain gauge wire grid, conductive silver paste and connecting wires to prevent damage during the test. The silicone rubber protective layer has good flexibility, corrosion resistance and water resistance, which can effectively protect the internal structure of the weighing sensor and extend the service life of the sensor.

[0014] Optionally, a central hole is provided through the surface of the weighing beam perpendicular to the surface where the strain gauge wire grid is installed. The central hole is a centrally symmetrical slot structure. Several cutting slots are also provided on the side of the load cell for weight reduction and isolation of installation stress. The central hole facilitates the installation and positioning of the load cell and reduces its weight. The cutting slots further reduce the weight of the load cell and improve its sensitivity and response speed.

[0015] Secondly, this utility model also provides a weighing sensor based on conductive carbon fiber, including a weighing beam, conductive silver paste, strain gauge wire grids, and connecting wires. The strain gauge wire grids are symmetrically fixed in eight groups at the top and bottom of the weighing beam, and each group has at least two strain gauge wire grids that are electrically connected to each other through conductive silver paste. The conductive silver paste is also provided at both ends of each group of strain gauge wire grids to form two connection points. One end of the connecting wires located at the top and bottom of the weighing beam is connected and fixed to the connection points, and the other end is soldered to the pads of the terminal block to form two sets of measuring bridges, realizing a dual-output sensor.

[0016] Two sets of measuring bridges are formed by symmetrically arranged strain gauge wire grids, electrical connection of conductive silver paste, and welding of connecting wires and terminals, thus realizing dual output function.

[0017] Optionally, each of the strain resistance wire grids consists of four resistive elements G1 to G4, connected in the form of a Wheatstone bridge.

[0018] Optionally, the top and bottom of the weighing beam are coated with glass glue, and the strain gauge wire grid is set on the glass glue by screen printing.

[0019] Optionally, the surface of the weighing beam is coated with a silicone rubber protective layer, which is uniformly covered on the strain gauge wire grid, conductive silver paste and connecting wires to prevent damage during the test.

[0020] Optionally, the weighing beam has a central hole through the surface perpendicular to the mounting strain resistance wire grid. The central hole is a centrally symmetrical groove structure. The side of the weighing sensor also has several cutting grooves for weight reduction and isolation of installation stress.

[0021] The weighing beam is also provided with two symmetrically arranged circular holes, the opening direction of which is opposite to the strain resistance wire grid. In addition to changing the stress distribution on the beam, the addition of a pair of circular holes can, more importantly, improve the sintering quality of the glass glue.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The weighing sensor based on conductive carbon fiber of this utility model connects the strain resistance wire grid with conductive silver paste to ensure the stability of electrical signal transmission. It also has good conductivity and adhesion properties, which can effectively reduce resistance and improve the sensitivity and response speed of the sensor. Through the innovative design of the strain resistance wire grid and the bridge connection scheme, combined with efficient environmental protection measures, the sensor has good stability, accuracy and service life.

[0024] 2. The load cell based on conductive carbon fiber of this utility model can effectively fix the strain resistance wire grid by using glass glue, and at the same time, it can also play a role in insulation and moisture protection. The silicone rubber protective layer has good flexibility, corrosion resistance and water resistance, which can effectively protect the internal structure of the load cell and extend the service life of the sensor. The central hole facilitates the installation and positioning of the load cell and can also reduce the weight of the load cell. By opening the cutting groove, the weight of the load cell can be further reduced, and the sensitivity and response speed of the sensor can be improved. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of this utility model;

[0026] Figure 2 This is a top view of the present invention;

[0027] Figure 3 For the present utility model Figure 2 Enlarged schematic diagram of the structure at point A;

[0028] Figure 4 This is a partial front view schematic diagram of the present invention;

[0029] Figure 5 This is a front view schematic diagram of the present invention with a central hole;

[0030] Figure 6 This is a top view schematic diagram of Embodiment 2 of the present invention;

[0031] Figure 7 This is a schematic diagram of the Wheatstone bridge formed by connecting the strain gauge wire grid of this utility model.

[0032] In the diagram: 1-Weighing beam, 2-Glass glue, 3-Conductive silver glue, 4-Strain gauge wire grid, 5-Connecting wire, 6-Center hole, 7-Mounting hole, 8-Silicone rubber protective layer, 9-Connection point, 10-Cutting groove, 11-Round hole. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention. Example 1

[0034] like Figures 1 to 5 As shown, a weighing sensor based on conductive carbon fiber is provided, including a weighing beam 1, conductive silver paste 3, strain gauge wire grid 4, and connecting wire 5. The strain gauge wire grid 4 is symmetrically arranged in four groups on the weighing beam 1. Each group of strain gauge wire grid 4 has at least two wires and they are electrically connected to each other through conductive silver paste 3. The conductive silver paste 3 is also provided at both ends of each group of strain gauge wire grid 4 to form two connection points 9. One end of the connecting wire 5 is connected and fixed to the connection point 9, and the other end is soldered to the pad of the terminal block to form a measuring bridge.

[0035] When using it, for the resistance measurement bridge of the load cell, the following can be adopted: Figure 1 and Figure 2 The connection is set up in such a way that four sets of strain resistance wire grids 4 are symmetrically fixed to the top and bottom of the weighing beam 1 in pairs. Each set of strain resistance wire grids 4 includes two strain resistance wire grids 4 and a conductive silver paste 3 inside, and the two strain resistance wire grids 4 are connected by the conductive silver paste 3.

[0036] It should be noted that in this embodiment, in addition to the possibility of having two strain resistance wire grids 4 in each group, there can also be any number of strain resistance wire grids 4. When there are two or more strain resistance wire grids 4, the electrical connection between adjacent strain resistance wire grids 4 is achieved by conductive silver paste 3.

[0037] When each group of strain resistance wire grids 4 is a single unit, two connection points 9 are formed at both ends of the strain resistance wire grid 4 directly through conductive silver paste, and then connected through connecting wires 5.

[0038] In this embodiment, in addition to symmetrically fixing the four sets of strain resistance wire grids 4 on the top and bottom of the weighing beam 1, the four sets of strain resistance wire grids 4 can also be symmetrically fixed on the same surface, which can also realize a single-set measuring bridge.

[0039] In use, the adjacent strain gauge wire grids 4 in each group are electrically connected by conductive silver paste 3 to ensure the stability of electrical signal transmission. It also has good conductivity and adhesion properties, which can effectively reduce resistance and improve the sensitivity and response speed of the sensor. Through the innovative design of the strain gauge wire grid 4 and the bridge connection scheme, combined with efficient environmental protection measures, the sensor has good stability, accuracy and service life.

[0040] refer to Figure 2 and Figure 3 As shown, in this embodiment, the supporting beam 1 is preferably an elastic element made of 17-4PH material, as is used in the prior art. The top mounting surface of the supporting beam 1 is also coated with glass glue 2. The strain gauge wire grid is fixed to the glass glue 2 by screen printing technology, as is used in the prior art. The connecting wire 5 is preferably a connecting wire made of conductive silver paste, as is used in the prior art. The curing temperature of the conductive silver paste is set to 130°C and maintained for 30 minutes to ensure good conductivity and long-term stability. The conductive silver paste 3 is preferably epoxy conductive silver paste, as is used in the prior art. In this embodiment, the point where the conductive silver paste 3 and the strain gauge wire grid 4 are connected is the connection point 9. One end of the connecting wire 5 is fixed at the connection point 9, and the other end is soldered to the pad of the terminal block using a soldering iron, as is used in the prior art, thus finally forming the measuring bridge of the sensor.

[0041] It should be noted that the reference Figure 1 As shown, in this embodiment, in order to better protect the sensitive grid, connecting wire 5 and pads, a layer of silicone rubber protective layer 8 is coated on the surface. The silicone rubber protective layer 8 is uniformly covered on the strain resistance wire grid 4, conductive silver paste 3 and connecting wire 5 to prevent damage during the test and to prevent the influence of dust and moisture.

[0042] refer to Figure 4 and Figure 5 As shown, in this embodiment, a central hole 6 is provided through the surface of the weighing beam 1 perpendicular to the surface of the strain gauge wire grid 4. The central hole 6 is a centrally symmetrical groove structure, which can be a circular groove, a square groove, a rhomboid groove, etc. In this embodiment, several cutting grooves 10 for weight reduction are also provided on the side of the weighing sensor. The weight to be removed can be calculated based on the overall weight of the manufactured weighing sensor. At the same time, mounting holes 7 are provided on both sides of the weighing beam 1 in this embodiment to facilitate installation and connection. The mounting holes 7 are preferably threaded hole structures in the prior art. Example 2

[0043] like Figure 6 As shown, based on Embodiment 1, this embodiment can also be designed as follows:

[0044] In this embodiment, the strain gauge wire grid 4 in Embodiment 1 is changed to eight groups. Four groups of strain gauge wire grid 4 are symmetrically fixed on the top of the weighing beam 1, and the other four groups are symmetrically fixed on the bottom of the weighing beam 1. Each group of strain gauge wire grid 4 consists of at least two wires and is electrically connected to each other by conductive silver paste 3. The conductive silver paste 3 is also provided at both ends of each group of strain gauge wire grid 4 to form two connection points 9. One end of the connecting wire 5 is connected and fixed to the connection point 9, and the other end is soldered to the pad of the terminal block to form two sets of measuring bridges to realize dual output sensors.

[0045] In this embodiment, the weighing beam 1 is also provided with two symmetrically arranged circular holes 11. The circular holes 11 are a pair and are symmetrically provided at the center of the weighing beam 1, and the opening direction is towards the strain resistance wire grid 4. By adding a pair of circular holes, in addition to changing the stress distribution on the beam, more importantly, it can improve the sintering quality of the glass glue.

[0046] It should be noted that each group of strain resistance wire grids 4 in this embodiment is also adapted to the setting and connection of a single strain resistance wire grid 4 in Embodiment 1, so it will not be described again here.

[0047] refer to Figure 7 As shown, the strain gauge wire grid 4 in this embodiment consists of four resistive elements G1 to G4, which are connected in the form of a Wheatstone bridge. G1 to G4 form a complete measurement bridge structure. The input (+EXC, -EXC) and output (+SIG, -SIG) terminals of the bridge are clearly marked in the figure to ensure accurate transmission and measurement of electrical signals.

[0048] The embodiments of the present utility model have been described above with reference to the accompanying drawings. However, the present utility model is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present utility model without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present utility model.

Claims

1. A weighing sensor based on conductive carbon fiber, characterized in that: The device includes a weighing beam (1), conductive silver paste (3), strain gauge wire grids (4), and connecting wires (5). The strain gauge wire grids (4) are arranged in four symmetrical groups on the weighing beam (1). Each group of strain gauge wire grids (4) consists of at least two wires and is electrically connected to each other through conductive silver paste (3). The conductive silver paste (3) is also provided at both ends of each group of strain gauge wire grids (4) to form two connection points (9). One end of the connecting wire (5) is connected and fixed to the connection point (9), and the other end is soldered to the pad of the terminal block to form a measuring bridge.

2. A weighing sensor based on conductive carbon fiber according to claim 1, characterized in that: The strain gauge wire grid (4) consists of four resistive elements G1 to G4, which are connected in the form of a Wheatstone bridge.

3. A weighing sensor based on conductive carbon fiber according to claim 2, characterized in that: The mounting surface of the weighing beam (1) is also coated with glass glue (2), and the strain resistance wire grid (4) is set on the glass glue (2) by screen printing.

4. A weighing sensor based on conductive carbon fiber according to claim 3, characterized in that: The surface of the weighing beam (1) is coated with a silicone rubber protective layer (8), which is uniformly covered on the strain resistance wire grid (4), conductive silver paste (3) and connecting wire (5) to prevent damage during the test.

5. A weighing sensor based on conductive carbon fiber according to claim 4, characterized in that: The weighing beam (1) has a central hole (6) through the surface perpendicular to the installation strain resistance wire grid (4). The central hole (6) is a centrally symmetrical groove structure. The side of the weighing sensor also has several cutting grooves (10) for weight reduction and isolation of installation stress.

6. A weighing sensor based on conductive carbon fiber, characterized in that: The weighing beam (1), conductive silver paste (3), strain gauge wire grid (4), and connecting wire (5) are included. The strain gauge wire grid (4) is symmetrically fixed in eight groups at the top and bottom of the weighing beam (1). Each group of strain gauge wire grid (4) consists of at least two wires and is electrically connected to each other through conductive silver paste (3). The conductive silver paste (3) is also provided at both ends of each group of strain gauge wire grid (4) to form two connection points (9). One end of the connecting wire (5) located at the top and bottom of the weighing beam (1) is connected and fixed to the connection point (9), and the other end is soldered to the pad of the terminal block to form two sets of measuring bridges to realize dual output sensors.

7. A weighing sensor based on conductive carbon fiber according to claim 6, characterized in that: Each of the strain resistance wire grids (4) consists of four resistive elements G1 to G4, connected in the form of a Wheatstone bridge.

8. A weighing sensor based on conductive carbon fiber according to claim 7, characterized in that: The top and bottom of the weighing beam (1) are coated with glass glue (2), and the strain resistance wire grid (4) is screen-printed on the glass glue (2).

9. A weighing sensor based on conductive carbon fiber according to claim 8, characterized in that: The surface of the weighing beam (1) is coated with a silicone rubber protective layer (8), which is uniformly covered on the strain resistance wire grid (4), conductive silver paste (3) and connecting wire (5) to prevent damage during the test.

10. A weighing sensor based on conductive carbon fiber according to claim 9, characterized in that: The weighing beam (1) has a central hole (6) through the surface perpendicular to the installation strain resistance wire grid (4). The central hole (6) is a centrally symmetrical groove structure. The side of the weighing sensor also has several cutting grooves (10) for weight reduction and isolation of installation stress. The weighing beam (1) is also provided with two symmetrically arranged circular holes (11), the opening direction of which is opposite to the strain resistance wire grid (4).

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