A force measuring device

Abstract

This utility model relates to a force measuring device, specifically addressing the problem in existing technologies where the bending of an elastic body caused by ambient temperature and external force affects force measurement results. The force measuring device comprises an elastic body and a bridge circuit. The elastic body deforms under the action of the measured external force. The bridge circuit includes strain gauges attached to the surface of the elastic body, which generate electrical signals corresponding to the deformation of the elastic body for detecting the measured external force. Two strain gauges connected to adjacent arms of the bridge circuit are attached to the same measurement area of ​​the elastic body, with their grid wires perpendicular to each other. One strain gauge's grid wire is positioned along the main axis of the elastic body to compensate for measurement errors introduced by temperature changes and bending strain. This utility model provides a force measuring device capable of suppressing the interference of ambient temperature and bending on measurement results, thus improving measurement accuracy.

Description

Technical Field

[0001] This utility model relates to the field of force measuring device technology, and in particular to a force measuring device. Background Technology

[0002] Force measuring devices are key equipment in fields such as industrial automation, experimental mechanics, and safety monitoring. Their core principle is usually to sense external force and generate deformation through an elastic body, and then use strain gauges adhered to the surface of the elastic body to convert the mechanical deformation into an electrical signal for measurement.

[0003] However, traditional strain gauge force measurement devices face several technical bottlenecks in practical applications. First, changes in ambient temperature cause thermal expansion and contraction of the elastic body and the strain gauge itself, introducing significant thermal output errors and reducing measurement accuracy. Second, in actual working conditions, it is difficult to ensure that the external force is applied absolutely along the principal axis of the elastic body; any slight off-center load or bending moment will generate additional bending strain. These non-target signals are mixed with the target tensile and compressive signals, reducing measurement accuracy.

[0004] Therefore, how to provide a force measuring device that can effectively suppress the interference of ambient temperature and bending on the measurement results is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] Based on the above analysis, the present invention aims to provide a force measuring device to solve the problem in the prior art where the bending of the elastic body caused by ambient temperature and external force affects the force measuring results.

[0006] The objective of this utility model is mainly achieved through the following technical solutions:

[0007] A force measuring device includes: an elastic body and a bridge circuit; the elastic body deforms under the action of a measured external force; the bridge circuit includes strain gauges attached to the surface of the elastic body, the strain gauges being used to generate an electrical signal corresponding to the deformation of the elastic body, for detecting the measured external force;

[0008] Two strain gauges connected to adjacent arms of the bridge are attached to the same measurement area of ​​the elastic body. The grid wires of the two strain gauges are perpendicular to each other, and the grid wire of one of the strain gauges is arranged along the main axis of the elastic body to compensate for the measurement error introduced by the temperature change and bending strain of the elastic body.

[0009] Furthermore, the two strain gauges are configured as a T-shaped strain gauge group.

[0010] Furthermore, the number of bridge circuits is two, one of which is the main measurement circuit, and the other is a backup circuit or auxiliary measurement circuit.

[0011] Furthermore, the bridge circuit is a Wheatstone full-bridge circuit; two sets of T-type strain gauges in one bridge circuit are symmetrically arranged with respect to the first axis of symmetry of the elastic body, and two sets of T-type strain gauges in the other bridge circuit are symmetrically arranged with respect to the second axis of symmetry of the elastic body, wherein the first axis of symmetry and the second axis of symmetry are perpendicular to each other.

[0012] Furthermore, the elastic body is a cylinder, which includes a measuring part and a non-measuring part; the non-measuring part is located at both ends of the measuring part, and the diameter of the non-measuring part is larger than the diameter of the measuring part.

[0013] Furthermore, the elastomer has a hollow accommodating cavity.

[0014] Furthermore, it also includes a battery pack, a battery box, and a strain data acquisition box fixed in the hollow cavity; the battery box is disposed inside the battery pack and is used to supply power to the strain data acquisition box; the strain data acquisition box is electrically connected to the strain gauge.

[0015] Furthermore, a display screen is provided on the side wall of the elastomer, and the display screen is located on the outer wall of the non-measuring part. The display screen is used to display the force measurement result.

[0016] Furthermore, it also includes a cable outlet and a charging interface, which are disposed in the non-measuring section.

[0017] Furthermore, it also includes cover plates disposed at both ends of the elastic body, and the cover plates are provided with connecting lugs. Compared with the prior art, this utility model can at least achieve the following:

[0018] Beneficial effects:

[0019] (1) The force measuring device of this utility model includes an elastic body and a bridge circuit. The bridge circuit includes strain gauges attached to the surface of the elastic body. By attaching two strain gauges connected to adjacent arms of the bridge circuit in the same measurement area with their grid wires perpendicular to each other, and with the grid wires of the strain gauges arranged along the main axis, the differential compensation principle of the bridge circuit is utilized. This arrangement causes the thermal expansion effect caused by temperature changes to produce resistance changes of equal magnitude and the same sign on adjacent arms, thus canceling each other out. At the same time, for bending strain in non-main axis directions, the vertically arranged strain gauges are subjected to tension and compression respectively, and the resulting resistance changes also cancel each other out. Finally, the bridge output signal eliminates temperature drift and bending interference, and is only sensitive to the measured external force in the main axis direction of the elastic body, significantly improving the accuracy and reliability of the measurement.

[0020] (2) In the force measuring device of this utility model, the two strain gauges connected to the adjacent bridge arm of the bridge are set as a T-shaped strain gauge group. On the one hand, it can realize the compact and orderly arrangement of the two strain gauges in the same measurement area of ​​the elastic body, avoid the problem of position deviation caused by the dispersed installation of strain gauges, ensure the stability of the vertical relationship of the grid wire, and ensure the error cancellation effect. On the other hand, the T-shaped structure is convenient for standardized production and batch assembly, reduces the alignment difficulty during strain gauge installation, improves assembly efficiency and consistency, and also provides convenience for subsequent connection with the bridge circuit, reducing the complexity of the circuit connection.

[0021] (3) In the force measuring device of this utility model, the bridge circuit adopts the Wheatstone full-bridge circuit, which has the advantages of high measurement accuracy, good linearity and large signal amplification factor. It can more sensitively capture the small electrical signal changes of the strain gauge and improve the measurement sensitivity. The two bridge circuits are arranged with two mutually perpendicular symmetrical axes relative to the elastic body. This not only forms a redundancy backup, but also fully captures the deformation of the elastic body under the action of external forces in different directions. It avoids local measurement deviation caused by uneven deformation distribution. Moreover, the vertical symmetrical arrangement can further offset the error caused by the asymmetrical deformation of the elastic body or external interference, so that the measurement performance of the full-bridge circuit can be fully utilized and the measurement accuracy and stability of the device under complex force scenarios can be greatly improved.

[0022] (4) In the force measuring device of this utility model, the elastic body is designed as a cylinder with a measuring part and a non-measuring part. The diameter of the non-measuring part is larger than that of the measuring part, which can concentrate the deformation of the elastic body under force into the measuring part with relatively low stiffness, reduce the interference of the deformation of the non-measuring part on the measurement, ensure that the strain gauge only detects the deformation directly related to the measured external force, and improve the measurement accuracy. The cylindrical structure of the elastic body has good symmetry, which can make the elastic body be subjected to uniform force in all directions, reduce stress concentration, and extend the service life of the elastic body. At the same time, the regular cylindrical structure also provides convenience for the symmetrical installation of the strain gauge, which is convenient to achieve the design goal of error compensation. Attached Figure Description

[0023] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0024] Figure 1 This is a schematic diagram of the force measuring device in an embodiment of the present invention;

[0025] Figure 2 This is a bridge circuit diagram in an embodiment of the present invention;

[0026] Figure 3 This is a cross-sectional view of the force measuring device in an embodiment of this utility model.

[0027] Figure label:

[0028] 1-Elastomer, 11-Measuring part, 12-Non-measuring part, 13-Hollow cavity;

[0029] 2-Bridge circuit, 21-Strain gauge;

[0030] 3-Battery pack;

[0031] 4-Battery box;

[0032] 5-Strain data acquisition box;

[0033] 6- Display screen;

[0034] 7-Cable outlet;

[0035] 8-Charging port;

[0036] 9-Cover plate, 91-Connecting lug. Detailed Implementation

[0037] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0038] A specific embodiment of this utility model is as follows: Figure 1 As shown, a force measuring device is disclosed, including: an elastic body 1 and a bridge circuit 2; the elastic body 1 deforms under the action of the measured external force; the bridge circuit 2 includes a strain gauge 21 attached to the surface of the elastic body 1, the strain gauge 21 is used to generate an electrical signal corresponding to the deformation of the elastic body 1, and to detect the measured external force.

[0039] Two strain gauges 21 connected to adjacent arms of the bridge are attached to the same measurement area of ​​the elastic body 1. The grid wires of the two strain gauges 21 are perpendicular to each other, and the grid wire of one strain gauge 21 is set along the main axis of the elastic body 1 to compensate for the measurement error introduced by the temperature change and bending strain of the elastic body 1.

[0040] In the force measuring device described in this embodiment, two strain gauges 21 connected to adjacent arms of the bridge are arranged in the same measurement area of ​​the elastic body 1 with their grid wires perpendicular to each other. One of them is arranged along the main axis of the elastic body 1, which can accurately offset the thermal expansion and contraction deformation of the elastic body 1 caused by temperature changes, as well as the interference of bending strain that may occur under external force on the measurement. This reduces the error introduced by non-target factors, and makes the electrical signal generated by the strain gauge 21 more realistically reflect the magnitude of the measured external force. This significantly improves the measurement accuracy and data reliability of the force measuring device, and ensures that it can still output accurate results stably under temperature fluctuations or complex stress scenarios.

[0041] Furthermore, the two strain gauges 21 are configured as a T-type strain gauge group, such as... Figure 1 As shown, R21 and R22, R23 and R24, R25 and R26, and R27 and R28 (R21, R22, R23, R24, R25, R26, R27, and R28 are all uniaxial semiconductor strain gauges) ensure that the grid wires of the two strain gauges 21 are perpendicular to each other. The T-shaped strain gauge group structure is more compact and standardized, which simplifies the bonding process and improves production efficiency and consistency. The compact T-shaped mechanism allows the two strain gauges 21 to be in the same temperature and stress environment, better achieving the effects of temperature compensation and anti-bending interference, and improving the stability and accuracy of the measurement.

[0042] Furthermore, the number of bridge circuits 2 is two: one bridge circuit 2 is the main measurement circuit, and the other bridge circuit 2 is a backup circuit or auxiliary measurement circuit. This improves the reliability and functionality of the force measuring device. When the main measurement circuit fails, the backup circuit can be switched on immediately, preventing the device from failing due to a single circuit failure, extending the effective working time of the device, and reducing maintenance downtime costs. If used as an auxiliary measurement circuit, it can collect data simultaneously with the main circuit, and mutual calibration can be achieved through data comparison, reducing measurement deviations.

[0043] Furthermore, bridge circuit 2 is a Wheatstone full-bridge circuit, such as... Figure 2 As shown, Figure 2 In the diagram, Vi+ represents the excitation voltage +, Vi- represents the excitation voltage -, Eg+ represents the measurement voltage +, and Eg- represents the measurement voltage -. The Wheatstone full-bridge circuit has advantages such as high measurement accuracy, good linearity, and large signal amplification, enabling it to more sensitively capture minute electrical signal changes in strain gauge 21 and improve measurement sensitivity. In the two bridge circuits 2, as shown... Figure 2 As shown, R21, R22, R25, and R26 form a bridge circuit 2, and R23, R24, R27, and R28 form another bridge circuit 2. Figure 1 As shown, the two sets of T-shaped strain gauges in one bridge circuit 2 are symmetrically arranged with respect to the first axis of symmetry of the elastic body 1, and the two sets of T-shaped strain gauges in the other bridge circuit 2 are symmetrically arranged with respect to the second axis of symmetry of the elastic body 1. The first and second axes of symmetry are perpendicular to each other. This arrangement of the two bridge circuits 2 can comprehensively capture the deformation of the elastic body 1 under external forces in different directions, avoiding local measurement deviations caused by uneven deformation distribution. Furthermore, the vertically symmetrical arrangement can further offset errors caused by asymmetrical deformation of the elastic body 1 or external interference, allowing the measurement performance of the full-bridge circuit to be fully utilized and improving the measurement accuracy and stability of the force measuring device under complex stress scenarios.

[0044] Furthermore, the elastic body 1 is a cylinder, which includes a measuring part 11 and a non-measuring part 12. The non-measuring part 12 is located at both ends of the measuring part 11, and its diameter is larger than that of the measuring part 11. The larger diameter of the non-measuring part 12 allows the deformation of the elastic body 1 under stress to be concentrated in the measuring part 11, which has relatively lower stiffness. This reduces the interference of the deformation of the non-measuring part 12 on the measurement, ensuring that the strain gauge 21 only detects the deformation directly related to the measured external force, thus improving measurement accuracy. The cylindrical structure has good symmetry, which allows the elastic body 1 to be subjected to uniform force in all directions, reducing stress concentration and extending the service life of the elastic body 1. The regular cylindrical structure also facilitates the symmetrical installation of the strain gauge 21, making it easier to achieve the design goal of error compensation.

[0045] Furthermore, such as Figure 3 As shown, the elastomer 1 has a hollow cavity 13. A battery pack 3, a battery box 4, and a strain data acquisition box 5 are disposed within the hollow cavity 13. The battery box 4 is located inside the battery pack 3 and supplies power to the strain data acquisition box 5. The strain data acquisition box 5 is electrically connected to the strain gauge 21. This achieves a high degree of integration of the force measuring device. The battery pack 3 provides independent power to the device, eliminating dependence on an external power source and significantly improving the device's portability, allowing it to be used in scenarios without an external power source. The battery box 4 protects the battery pack 3, preventing damage to the battery due to vibration and impact, and extending battery life. The strain data acquisition box 5 is directly electrically connected to the strain gauge 21, shortening the signal transmission distance, reducing signal attenuation and interference during transmission, and improving the timeliness and accuracy of data acquisition.

[0046] Furthermore, it also includes a display screen 6, which is installed on the outer wall of the non-measuring section 12. The display screen 6 is used to display the force measurement results. This enables real-time visualization of the force measurement data, allowing users to directly read the measurement results without the need for external equipment, making operation convenient and improving efficiency. The display screen 6 is located on the outer wall of the non-measuring section 12, and its position is directly related to the measurement area. Users can intuitively see the display results and their corresponding current measurement status, making it easy to keep track of the force measurement situation.

[0047] Furthermore, the elastomer 1 includes a wire outlet 7 and a charging interface 8, which are located in the non-measuring section 12. The wire outlet 7 facilitates the orderly exit of the wires of the strain gauge 21 or internal components, preventing the wires from becoming tangled and affecting the use of the device or causing damage; the charging interface 8 connects to an external power source to charge the battery box 4.

[0048] Furthermore, it also includes a cover plate 9, which is disposed at both ends of the elastomer 1, and the cover plate 9 is provided with connecting lugs 91.

[0049] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A force measuring device, characterized in that, include: An elastomer (1) and a bridge circuit (2); the elastomer (1) deforms under the action of the measured external force; the bridge circuit (2) includes a strain gauge (21) attached to the surface of the elastomer (1), the strain gauge (21) is used to generate an electrical signal corresponding to the deformation of the elastomer (1) to detect the measured external force; Two strain gauges (21) connected to adjacent arms of the bridge are attached to the same measurement area of ​​the elastic body (1). The grid wires of the two strain gauges (21) are perpendicular to each other, and the grid wire of one of the strain gauges (21) is arranged along the main axis of the elastic body (1) to offset the measurement error introduced by the temperature change and bending strain of the elastic body (1).

2. The force measuring device according to claim 1, characterized in that, The two strain gauges (21) are configured as a T-type strain gauge group.

3. The force measuring device according to claim 1 or 2, characterized in that, The number of bridge circuits (2) is two. One bridge circuit (2) is the main measurement circuit, and the other bridge circuit (2) is a backup circuit or an auxiliary measurement circuit.

4. The force measuring device according to claim 3, characterized in that, The bridge circuit (2) is a Wheatstone full-bridge circuit; two sets of T-type strain gauges of one bridge circuit (2) are symmetrically arranged with respect to the first axis of symmetry of the elastic body (1), and two sets of T-type strain gauges of the other bridge circuit (2) are symmetrically arranged with respect to the second axis of symmetry of the elastic body (1), and the first axis of symmetry and the second axis of symmetry are perpendicular to each other.

5. The force measuring device according to claim 1, characterized in that, The elastic body (1) is a cylinder, which includes a measuring part (11) and a non-measuring part (12); the non-measuring part (12) is located at both ends of the measuring part (11), and the diameter of the non-measuring part (12) is larger than the diameter of the measuring part (11).

6. The force measuring device according to claim 1, characterized in that, The elastomer (1) has a hollow cavity (13).

7. The force measuring device according to claim 6, characterized in that, It also includes a battery pack (3), a battery box (4) and a strain data acquisition box (5) fixed in the hollow cavity (13); the battery box (4) is disposed in the battery pack (3) and is used to supply power to the strain data acquisition box (5); the strain data acquisition box (5) is electrically connected to the strain gauge (21).

8. The force measuring device according to claim 5, characterized in that, It also includes a display screen (6), which is disposed on the outer wall of the non-measuring part (12) and is used to display the force measurement results.

9. The force measuring device according to claim 5, characterized in that, It also includes a wire outlet (7) and a charging interface (8), which are provided in the non-measuring section (12).

10. The force measuring device according to claim 1, characterized in that, It also includes a cover plate (9), which is disposed at both ends of the elastomer (1), and the cover plate (9) is provided with connecting lugs (91).

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