Full-bridge resistance strain sensor

Abstract

The utility model belongs to the technical field of strain measurement, and provides a full-bridge resistance strain sensor which comprises a bottom plate, a stress elastic plate is arranged on the bottom plate, a circular groove is formed in the stress elastic plate, and a first threaded hole is formed in the stress elastic plate; according to the utility model, four traditional strain gauges are combined into a brand-new full-bridge strain gauge in cooperation with the connecting ring, and the resistance strain gauge is integrally formed, so that only one-time surface mounting is needed, the number of welding leads is reduced, the construction process is simplified, the processing efficiency is improved, the precision of the sensor is greatly improved, and the cost is reduced. The sensor is connected with a to-be-measured object through a wire, it is guaranteed that the sensor can be subjected to the strain effect, the change of the resistance value in the full-bridge circuit is detected, the dependent variable is converted into an electric signal to be output, and therefore strain measurement is achieved, and the strain gauges and the wire can be effectively protected through the design of the protection assembly; and the influence of external environmental factors on the measurement result is prevented.

Description

TECHNICAL FIELD

[0001] The utility model belongs to strain measurement technical field, specifically, a full bridge resistance strain sensor. BACKGROUND

[0002] Full bridge strain sensor is a kind of sensor for measuring the deformation (strain) of object, usually by four strain gauges, according to the way of bridge circuit connection. These strain gauges are usually pasted on the surface of the measured object. When the object is stressed, deformation occurs, resulting in resistance change of strain gauge, and the full bridge circuit can accurately measure the small deformation by comparing the resistance change, so as to calculate the force or pressure applied to the object.

[0003] However, the traditional resistance strain sensor is four single-axis strain gauges pasted on the measured object one by one, and then a full bridge circuit is formed by wires. This way requires four times of pasting for four strain gauges, and positioning is required each time, which greatly reduces the accuracy of the sensor and makes the pasting process complex. Therefore, the technical personnel in the field propose a full bridge resistance strain sensor to solve the problem raised in the background art.

[0004] The above information disclosed in the background art is only used to increase the understanding of the background art of the utility model, therefore, it can include prior art known by those skilled in the art. CONTENT OF THE UTILITY MODEL

[0005] In order to solve the above technical problems, the utility model provides a full bridge resistance strain sensor to solve the problem that four strain gauges need to be pasted four times and positioning is required each time in the prior art.

[0006] To achieve the above purpose, the utility model provides a full bridge resistance strain sensor, which comprises a bottom plate, a stress elastic plate is arranged on the bottom plate, a circular groove is formed in the stress elastic plate, a first threaded hole is formed in the stress elastic plate, at least two holes are symmetrically formed in the stress elastic plate, at least two pieces of foam gasket are symmetrically arranged on the stress elastic plate, a connecting ring is arranged in the circular groove, a plurality of strain gauges are arranged on the connecting ring, a threading plate is arranged at the bottom of the stress elastic plate, a first bolt is rotatably connected to the threading plate, a wire is arranged between the stress elastic plate and the threading plate, and a protection assembly is arranged between the two foam gaskets.

[0007] Preferably, the first bolt is threadedly connected in the first threaded hole, and the first threaded hole and the first bolt are both provided with a plurality of holes.

[0008] Preferably, the protection assembly comprises an upper cover plate and a lower cover plate arranged between two pieces of foam pads, the upper cover plate is provided with a second threaded hole at the bottom, and the lower cover plate is rotatably connected with a second bolt.

[0009] Preferably, the upper cover plate and the lower cover plate are in abutment, the second bolt is threadedly connected in the second threaded hole, and the second threaded hole and the second bolt are both provided with two and symmetrically arranged.

[0010] Preferably, the stress elastic plate is provided with a fixing assembly, the fixing assembly comprises a third bolt arranged in the hole, the third bolt is fixedly connected with a fixing plate at the bottom, and the third bolt is threadedly connected with a nut outside.

[0011] Preferably, the fixing plate is arranged on the top of the bottom plate, and the fixing assembly is provided with two and symmetrically arranged.

[0012] Compared with the prior art, the full-bridge resistance strain sensor has the following beneficial effects:

[0013] 1、 the full-bridge resistance strain sensor of the utility model discloses a traditional four strain gauges are combined into a brand-new full-bridge strain gauge, since the resistance strain gauge is integrally formed, only one patching is needed, and the number of welding wires is also reduced, which not only simplifies the construction process, improves the processing efficiency, but also greatly improves the sensor precision, the sensor is connected with the object to be measured through wires, and the strain effect is ensured, the strain amount is converted into an electric signal output by detecting the resistance value change in the full-bridge circuit, so that the strain measurement is realized, and the strain gauge and the wire can be effectively protected by the design of the protection assembly, and the influence of external environmental factors on the measurement result is prevented.

[0014] 2、 the third bolt and the nut are matched, and the fixing plate is adhered, so that the sensor is fixedly installed on the bottom plate or the object to be measured, the structure of the sensor is more stable, and the measurement accuracy and reliability are further improved.

[0015] The above summary is only for the purpose of the description and is not intended to limit in any way. In addition to the above-described exemplary aspects, embodiments and features, further aspects, embodiments and features of the utility model will be readily apparent to those skilled in the art by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a whole structure schematic view of a full-bridge resistance strain sensor in the embodiment of the utility model;

[0017] Figure 2 It is a sectional view of a full-bridge resistance strain sensor in the embodiment of the utility model;

[0018] Figure 3 It is a structure exploded schematic view of a full-bridge resistance strain sensor in the embodiment of the utility model;

[0019] Figure 4 It is a structure exploded schematic view of a full-bridge resistance strain sensor fixing assembly in the embodiment of the utility model.

[0020] In the drawing,

[0021] 1, bottom plate;2, stress elastic plate;21, round groove;22, first threaded hole;23, hole;3, foam pad;4, connecting ring;41, strain gauge;5, threading plate;51, first bolt;6, wire;7, protection assembly;71, upper cover plate;72, second threaded hole;73, lower cover plate;74, second bolt;8, fixing assembly;81, third bolt;82, fixed plate;83, nut. Specific embodiments

[0022] The technical scheme in the embodiments of the utility model will be described clearly and completely below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. It should be pointed out that the drawings are schematic and not drawn to scale. In order to be clear and convenient in the drawing, the relative size and proportion of the parts shown in the drawing are exaggerated or reduced in size for illustration, and any size is only exemplary, not limiting.

[0023] Embodiment one:

[0024] Please refer to Figure 1 - Figure 4As shown, a full-bridge resistance strain sensor, including a base plate 1, a stress elastic plate 2 is arranged on the base plate 1, a circular groove 21 is arranged on the stress elastic plate 2, a first threaded hole 22 is arranged on the stress elastic plate 2, at least two holes 23 are symmetrically arranged on the stress elastic plate 2, at least two foam gaskets 3 are symmetrically arranged on the stress elastic plate 2, a connecting ring 4 is arranged in the circular groove 21, a plurality of strain gauges 41 are arranged on the connecting ring 4, a threading plate 5 is arranged at the bottom of the stress elastic plate 2, a first bolt 51 is rotatably connected to the threading plate 5, a wire 6 is arranged between the stress elastic plate 2 and the threading plate 5, a protection assembly 7 is arranged between the two foam gaskets 3, the base plate 1 serves as the basic support structure of the entire strain sensor, used for mounting and fixing other components, the base plate 1 can be attached to the measured object, and the base plate 1 can be disassembled, so that the sensor is directly installed on the measured object, the stress elastic plate 2 is used to bear and transmit the stress and strain of the measured object, when the measured object deforms, the stress elastic plate 2 deforms accordingly, thereby driving the strain gauge 41 to produce resistance change, the circular groove 21 is used to install the connecting ring 4, ensuring the close combination of the connecting ring 4 and the stress elastic plate 2, the first threaded hole 22 is used to install the first bolt 51, fixing the connection between the stress elastic plate 2 and the threading plate 5, the hole 23 is used to install the fixing assembly 8, ensuring the fixation between the stress elastic plate 2 and the base plate 1 or the measured object, the foam gasket 3 is used to prevent the influence of external impact and vibration on the measurement result, reduce the interference of environmental factors on the sensor, improve the stability and reliability of the sensor, the connecting ring 4 cooperates with the four strain gauges 41 to combine into a brand new full-bridge strain gauge, the strain gauge 41 is a foil metal strain gauge 41, which is composed of a sensitive grid, a substrate, a cover layer and a lead wire, the sensitive grid is the most critical part, which is made into the required sensitive grid pattern by photolithography, etching and other processes, and is pasted on the polyimide substrate sheet, the threading plate 5 is used to fix the wire 6, ensuring the neatness and stability of the wire 6, the first bolt 51 is used to connect the stress elastic plate 2 and the threading plate 5, ensuring the fixation between the two, the wire 6 is used to connect the strain gauge 41 and the external measurement circuit, transmitting the resistance change signal of the strain gauge 41 to the measuring device, the protection assembly 7 is used to protect the strain gauge 41 and the wire 6, preventing the influence of external environmental factors (such as dust, moisture, etc.) on the sensor.

[0025] Specifically, the first bolt 51 is threadedly connected in the first threaded hole 22, and the first threaded hole 22 and the first bolt 51 are both provided with a plurality of.

[0026] Further, the protection assembly 7 comprises an upper cover plate 71 and a lower cover plate 73 arranged between the two pieces of foam pads 3, the upper cover plate 71 is provided with a second threaded hole 72 at the bottom, the lower cover plate 73 is rotatably connected with a second bolt 74, the upper cover plate 71 is used for covering the strain gauge 41 and the wire 6 to provide physical protection, the lower cover plate 73 is used for supporting the upper cover plate 71 to form a closed protection space, the second threaded hole 72 is used for installing the second bolt 74 to fix the upper cover plate 71 and the lower cover plate 73, and the second bolt 74 is used for fixing the upper cover plate 71 and the lower cover plate 73 to ensure the tightness of the protection assembly 7.

[0027] Further, the upper cover plate 71 and the lower cover plate 73 are in close contact, the second bolt 74 is threadedly connected in the second threaded hole 72, and the second threaded hole 72 and the second bolt 74 are both provided with two symmetrically arranged ones.

[0028] As can be seen from the above, first, the connecting ring 4 is installed on the stress elastic plate 2, and a plurality of strain gauges 41 are installed on the connecting ring 4, which are combined into a brand-new full-bridge strain gauge, the wire 6 is connected to the full-bridge strain gauge, and the wire 6 is fixed through the threading plate 5, the full-bridge strain gauge and the stress elastic plate 2 are bonded with epoxy resin glue, and the bonding position is sandblasted and polished before bonding, and cleaned with acetone or butanone, to ensure the firmness and accuracy of the bonding;

[0029] When the measured object is subjected to external force, the stress elastic plate 2 deforms, driving the strain gauge 41 to change the resistance, the resistance change of the strain gauge 41 is transmitted to the external measurement circuit through the wire 6 to form an electrical signal output, and the strain of the measured object is calculated by measuring the change of the electrical signal, since the resistance strain gauge 41 is integrally formed, only one patching is needed, and the traditional four strain gauges 41 need 8 wires (4 power lines and 4 signal lines), which need to be welded or connected to the strain gauges 41 respectively and connected to the measurement circuit through a complex wiring method, since the full-bridge strain gauge is a whole, the internal bridge connection has been completed, so only 4 wires (two power lines and two signal lines) are needed to complete the connection with the external measurement circuit, the number of welded wires 6 is reduced, not only simplifying the construction process and improving the processing efficiency, but also greatly improving the sensor accuracy;

[0030] The resistance change of the strain gauge 41 is converted into an electrical signal output by a full-bridge circuit. The full-bridge circuit utilizes the principle of a Wheatstone bridge, which is a classic resistance measurement circuit composed of four resistors in a closed loop. When the bridge is balanced, the output voltage is zero. When the bridge is unbalanced, the output voltage is proportional to the resistance change. The four strain gauges 41 are connected to the four arms of the bridge, respectively. When the strain gauge 41 is subjected to strain, there is a linear relationship between the bridge output voltage and the strain value. The strain is converted into an electrical signal output by detecting the change in resistance in the full-bridge circuit. The electrical signal output by the sensor is usually very weak and needs to be amplified by an amplifier to make it accurately readable by the data acquisition system. The amplified signal is then filtered by the acquisition instrument to remove noise interference. The processed signal is then sent to the base station, which converts the received analog signal into a digital signal and performs data processing and analysis through a computer. The host computer software decodes, calibrates, and performs secondary filtering on the strain data. The results are finally displayed dynamically in the form of a waveform graph, a spectrum graph, or a numerical panel, and are simultaneously stored in a local database or file. The design of the protection assembly 7 can effectively protect the strain gauge 41 and the wire 6, preventing external environmental factors from affecting the measurement results.

[0031] Embodiment Two:

[0032] Please refer to Figure 4 The difference between this embodiment and the previous embodiment is that the stress elastic plate 2 is provided with a fixing assembly 8. The fixing assembly 8 includes a third bolt 81 arranged in the hole 23, a fixed plate 82 fixedly connected to the bottom of the third bolt 81, and a nut 83 threadedly connected to the outside of the third bolt 81. The fixing assembly 8 is used to fix the stress elastic plate 2 on the base plate 1 or the measured object, ensuring the stability of the overall structure of the sensor and preventing displacement or loosening of the sensor during measurement. The third bolt 81 is used to connect the stress elastic plate 2 and the fixed plate 82, ensuring the fixation between the two. The fixed plate 82 is used to be installed on the base plate 1 or the measured object, providing additional support and fixation. The nut 83 is used to tighten the third bolt 81, ensuring the stability of the fixing assembly 8.

[0033] Specifically, the fixed plate 82 is arranged on the top of the base plate 1, and the fixing assembly 8 is provided with two symmetrically arranged fixed plates 82.

[0034] As can be seen from the above, the sensor is fixedly installed on the base plate 1 or the measured object by the cooperation of the third bolt 81 and the nut 83, as well as the adhesion of the fixed plate 82, making the structure of the sensor more stable and further improving the measurement accuracy and reliability.

[0035] The standard parts used in the utility model can be purchased from the market, the special-shaped parts can be ordered according to the description and the drawings, the specific connection mode of each part adopts the conventional means such as bolts, rivets and welding in the prior art, the mechanical, part and equipment adopt the conventional type in the prior art, and the circuit connection adopts the conventional connection mode in the prior art, and details are not described herein.

[0036] The utility model discloses the drawings in the embodiment, only relate to the structure involved in the embodiment of the disclosure, other structures can refer to the usual design, under the condition of not conflicting, the same embodiment and different embodiments of the utility model can be combined mutually.

[0037] Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical scheme recorded in the foregoing embodiments or make equivalent replacement to part of the technical features, and any modification, equivalent replacement, improvement and the like within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A full-bridge resistive strain sensor, characterized by: Including, The bottom plate (1) is provided with a stress elastic plate (2), a circular groove (21) is opened in the stress elastic plate (2), a first threaded hole (22) is opened in the stress elastic plate (2), at least two holes (23) are symmetrically opened in the stress elastic plate (2), at least two pieces of foam pads (3) are symmetrically arranged on the stress elastic plate (2), a connecting ring (4) is arranged in the circular groove (21), a plurality of strain gauges (41) are arranged on the connecting ring (4), a threading plate (5) is arranged at the bottom of the stress elastic plate (2), a first bolt (51) is rotatably connected to the threading plate (5), a wire (6) is arranged between the stress elastic plate (2) and the threading plate (5), and a protection assembly (7) is arranged between the two foam pads (3).

2. A full-bridge resistive strain sensor according to claim 1, characterized in that: The first bolt (51) is threadedly connected in the first threaded hole (22), and the first threaded hole (22) and the first bolt (51) are both provided with a plurality of.

3. A full-bridge resistive strain sensor according to claim 2, characterized in that: The protection assembly (7) comprises an upper cover plate (71) and a lower cover plate (73) arranged between the two foam pads (3), the upper cover plate (71) is provided with a second threaded hole (72) at the bottom, and the lower cover plate (73) is rotatably connected with a second bolt (74).

4. A full-bridge resistive strain sensor according to claim 3, characterized in that: The upper cover plate (71) and the lower cover plate (73) are attached to each other, the second bolt (74) is threadedly connected in the second threaded hole (72), and the second threaded hole (72) and the second bolt (74) are both provided with two and symmetrically arranged.

5. A full-bridge resistive strain sensor according to claim 4, characterized in that: The stress elastic plate (2) is provided with a fixing assembly (8), the fixing assembly (8) comprises a third bolt (81) arranged in the hole (23), the third bolt (81) is fixedly connected with a fixing plate (82) at the bottom, and the third bolt (81) is threadedly connected with a nut (83) outside.

6. A full-bridge resistive strain sensor according to claim 5, characterized in that: The fixing plate (82) is arranged on the top of the bottom plate (1), and the fixing assembly (8) is provided with two and symmetrically arranged.

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