A metal crack displacement sensor

Abstract

The utility model discloses a kind of metal crack displacement sensors, belong to displacement sensor technical field, including elastomer and fixed leg, elastomer is annular with opening, two fixed legs are fixedly connected at the two ends of elastomer opening respectively, the upper end of elastomer is provided with strain area, strain area is fixedly connected with first strain gauge, second strain gauge, third strain gauge and fourth strain gauge, first strain gauge, second strain gauge, third strain gauge and fourth strain gauge are connected with full-bridge detection circuit;The utility model is straddled in the two sides of crack by fixed leg and fixed, when crack generates displacement, strain area is located at the upper end of elastomer, displacement also can be amplified by elastomer, concentrate in the strain area of the upper end of elastomer, to generate voltage difference, when crack opens or closes, can output electric signal, it is convenient for real-time detection and record, linearity is good, precision is higher, can reach submicron level, simple structure low in cost.

Description

Technical Field

[0001] This utility model relates to the field of displacement sensor technology, specifically to a metal crack displacement sensor. Background Technology

[0002] Detecting crack opening displacement in metallic materials is a key step in assessing structural integrity, predicting remaining life, and performing failure analysis. Depending on the detection principle, accuracy, and application scenario, there are contact methods, non-contact methods, and non-destructive testing. In recent years, with the development of technology, the accuracy requirements for displacement sensors have become increasingly higher, moving towards the micrometer, submicrometer, and nanometer scales, and displacement sensors have become increasingly precise. However, in the existing technology, crack monitoring in automobile body structure, key chassis components, engine cylinder block and gearbox housing; including aerospace parts, rail transit vehicle structure and other fields, requires relatively accurate crack detection. The structure of the tested parts is installed in a relatively compact space, and the structure of the tested parts is varied and complex, making it difficult to install displacement sensors. See the strain-type micro-nano displacement sensor with publication number CN101435690A. Existing high-precision displacement sensors are large in size, have high installation requirements, and high operating costs, making them difficult to apply to complex environments in confined spaces. On the other hand, displacement sensors with simple structures are not accurate enough to obtain accurate detection results. Therefore, considering both accuracy and cost, and facilitating use in confined spaces, a metal crack displacement sensor is proposed. Utility Model Content

[0003] The purpose of this invention is to provide a metal crack displacement sensor, which solves the technical problems of existing high-precision displacement sensors having large size, high installation requirements, and high operating costs.

[0004] The objective of this utility model can be achieved through the following technical solutions: A metal crack displacement sensor includes an elastic body and fixed legs. The elastic body is annular with an opening at the bottom. Two fixed legs are respectively fixedly connected to the two ends of the opening of the elastic body. The upper part of the elastic body corresponding to the opening is configured as a strain zone. A first strain gauge, a second strain gauge, a third strain gauge, and a fourth strain gauge are respectively fixedly connected to the strain zone. The first strain gauge, the second strain gauge, the third strain gauge, and the fourth strain gauge are connected in a full-bridge detection circuit.

[0005] Furthermore, the first strain gauge and the third strain gauge are fixedly connected to the upper end of the strain zone; the second strain gauge and the fourth strain gauge are fixedly connected to the lower end of the strain zone.

[0006] Furthermore, the structures of the elastic body and the fixed support are both symmetrical from left to right.

[0007] Furthermore, the first strain gauge and the fourth strain gauge have the same initial resistance, and the second strain gauge and the third strain gauge have the same initial resistance.

[0008] Furthermore, the initial resistance values ​​of the first strain gauge, the second strain gauge, the third strain gauge, and the fourth strain gauge are 350 ohms and / or 750 ohms.

[0009] Furthermore, the fixed support leg is welded to the elastomer.

[0010] Furthermore, the fixed support leg is provided with a connecting groove.

[0011] Furthermore, it also includes an adapter tooling, which is detachably connected to the fixed support leg via a connecting groove.

[0012] Furthermore, the adapter includes a connecting part, a relief part, and a fitting part. The fixed support is detachably connected to the connecting part. One end of the relief part is fixedly connected to the connecting part, and the other end is connected to the fitting part. The two fitting parts are used to fix the connection to both sides of the crack.

[0013] Furthermore, the fixed support leg is connected to the connecting part by bolts.

[0014] The beneficial effects of this utility model are: (1) When the elastic body is subjected to force and strain occurs, the resistance of the first strain gauge, the second strain gauge, the third strain gauge and the fourth strain gauge change. The fixed support straddles both sides of the crack and is fixed. When the crack is displaced, the strain zone is located at the upper end of the elastic body. The displacement is also amplified by the elastic body and concentrated in the strain zone at the upper end of the elastic body, thereby generating a voltage difference. When the crack opens or closes, an electrical signal can be output, which is convenient for real-time detection and recording. It has good linearity, high accuracy, and can reach the submicron level. The structure is simple and the cost is low. (2) The installation is convenient and simple through the transfer and displacement transmission of the fixed support feet. The fixed support feet occupy little connection space, which makes it easy for the displacement sensor to avoid interference during installation and facilitates connection and detection in narrow spaces. (3) By combining the elastomer with the fixed support, the cost of submicron level sensors is reduced, the installation process and required installation space are simplified, and it can be applied to high-precision detection requirements in narrow spaces. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 This is a top view illustrating the structure of this utility model; Figure 2 This is a schematic diagram of the strain zone structure of this utility model; Figure 3 This is a schematic diagram of the equivalent bridge principle of this utility model; Figure 4 This is a schematic diagram of the connection structure of the adapter tool of this utility model.

[0017] In the figure: 1-elastic body, 11-strain zone, 111-first strain gauge, 112-second strain gauge, 113-third strain gauge, 114-fourth strain gauge, 2-fixed support, 21-connecting groove, 3-transfer fixture, 31-connecting part, 32-leaking part, 33-fitting part. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings showing multiple embodiments according to this application. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," etc., in the description, claims, and accompanying drawings of this application are open-ended terms. Therefore, "comprising," "including," or "having" refers to, for example, a method or apparatus having one or more steps or elements, but is not limited to having only these one or more elements. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0020] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] Furthermore, in the attached diagram, the X-axis represents the vertical direction, that is, the front-to-back position, and the positive direction of the X-axis (that is, the direction the arrow points to) represents the front, and the negative direction of the X-axis (that is, the direction opposite to the positive direction of the X-axis) represents the back; in the attached diagram, the Y-axis represents the horizontal direction, that is, the left-to-right position, and the positive direction of the Y-axis (that is, the direction the arrow points to) represents the left, and the negative direction of the Y-axis (that is, the direction opposite to the positive direction of the Y-axis) represents the right; in the attached diagram, the Z-axis represents the vertical direction, that is, the up-to-down position, and the positive direction of the Z-axis (that is, the direction the arrow points to) represents the up, and the negative direction of the Z-axis (that is, the direction opposite to the positive direction of the Z-axis) represents the down.

[0022] It should also be noted that the meanings of the aforementioned X-axis, Y-axis and Z-axis are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] It should be emphasized that when the term "comprising / including" is used in this specification, it is used to explicitly indicate the presence of the stated feature, integer, step, or component, but does not exclude the presence or addition of one or more other features, integers, steps, components, or groups of features, integers, steps, or components.

[0025] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0026] Please see Figure 1-3As shown, this utility model is a metal crack displacement sensor, including an elastic body 1 and fixed legs 2. The elastic body 1 is annular with an opening at the bottom. Two fixed legs 2 are respectively fixedly connected to the two ends of the opening of the elastic body 1. The upper part of the elastic body 1 corresponding to the opening is configured as a strain zone 11. The strain zone 11 is respectively fixedly connected to a first strain gauge 111, a second strain gauge 112, a third strain gauge 113 and a fourth strain gauge 114. The first strain gauge 111, the second strain gauge 112, the third strain gauge 113 and the fourth strain gauge 114 are connected in a full-bridge detection circuit.

[0027] In this embodiment, before use, the first strain gauge 111R1, the second strain gauge 112R2, the third strain gauge 113R3, and the fourth strain gauge 114R4 form a Wheatstone full-bridge circuit. The first strain gauge 111, the second strain gauge 112, the third strain gauge 113, and the fourth strain gauge 114 are connected in series to form a closed loop, constituting the four arms of the Wheatstone full-bridge circuit. The connection point of the first strain gauge 111 and the second strain gauge 112, and the connection point of the third strain gauge 113 and the fourth strain gauge 114 serve as the sampling point of the output voltage e. The connection point of the first strain gauge 111 and the fourth strain gauge 114, and the connection point of the second strain gauge 112 and the third strain gauge 113 serve as the connection terminal of the input voltage E. When the elastic body 1 is subjected to force and generates strain, the resistance R1 of the first strain gauge 111, the resistance R2 of the second strain gauge 112, the resistance R3 of the third strain gauge 113, and the resistance R4 of the fourth strain gauge 114 change by ΔR1, ΔR2, ΔR3, and ΔR4, respectively, converting the strain signal into an electrical signal, thereby obtaining the output voltage change e. By analyzing the relationship between the output voltage e and the loaded displacement signal, the sensitivity coefficient of the sensor is calibrated. Using the sensitivity coefficient, the displacement sensor can be used to test metal cracks or small displacements.

[0028] In use, the fixed support 2 straddles and fixes the crack on both sides. When the crack displaces, the strain zone 11 is located at the upper end of the elastic body 1. The displacement is amplified by the elastic body 1 and concentrated in the strain zone 11 at the upper end of the elastic body 1, thus generating a voltage difference. It should be noted that the first strain gauge 111, the second strain gauge 112, the third strain gauge 113, and the fourth strain gauge 114 are installed at different positions in the strain zone 11, so that the deformation is different, thus enabling the detection of the voltage difference and the displacement distance. The connection method of the full-bridge detection circuit is existing technology, using a Wheatstone full-bridge detection circuit for connection. The way the first strain gauge 111, the second strain gauge 112, the third strain gauge 113, and the fourth strain gauge 114 are fixed in the strain zone 11 is also existing technology, so it will not be described in detail. When the crack opens or closes, it can output an electrical signal, which is convenient for real-time detection and recording. It has good linearity, high accuracy, and can reach the submicron level. It also has a simple structure and low cost.

[0029] The installation is convenient and simple due to the connection and displacement transmission via the fixed support 2. The fixed support 2 occupies little connection space, which makes it easy for the displacement sensor to be installed without interference, and facilitates connection and detection in confined spaces.

[0030] See Figure 1-3 Optionally, the first strain gauge 111 and the third strain gauge 113 are fixedly connected to the upper end of the strain zone 11, respectively; the second strain gauge 112 and the fourth strain gauge 114 are fixedly connected to the lower end of the strain zone 11, respectively.

[0031] In this embodiment, when the fixed support 2 straddles both sides of the crack, when the crack expands, the deformation of the elastic body 1 will be concentrated in the deformation zone at the upper end of the elastic body 1. The first strain gauge 111 and the third strain gauge 113 located on the upper side of the deformation zone will be compressed as the crack expands, and the second strain gauge 112 and the fourth strain gauge 114 located on the lower side of the deformation zone will be stretched as the crack expands. When the crack shrinks, the first strain gauge 111 and the third strain gauge 113 located on the upper side of the deformation zone will be stretched as the crack shrinks, and the second strain gauge 112 and the fourth strain gauge 114 located on the lower side of the deformation zone will be compressed as the crack shrinks. This further amplifies the potential difference e at the potential detection point, thereby improving the detection accuracy and enabling the detection requirements to be met with a smaller volume.

[0032] See Figure 1-3 Optionally, the structures of the elastic body 1 and the fixed support 2 are both symmetrical from left to right. In this embodiment, the deformation can be made more uniform and controllable, and the linearity can be improved.

[0033] See Figure 1-3 Optionally, the first strain gauge 111 and the fourth strain gauge 114 have the same initial resistance, and the second strain gauge 112 and the third strain gauge 113 have the same initial resistance. The initial resistance of the first strain gauge 111, the second strain gauge 112, the third strain gauge 113 and the fourth strain gauge 114 is 350 ohms and / or 750 ohms. In this embodiment, the first strain gauge 111 and the third strain gauge 113 can be arranged side by side in the front-to-back direction, and the second strain gauge 112 and the fourth strain gauge 114 can also be arranged side by side in the front-to-back direction, which can improve the consistency of deformation of the first strain gauge 111 and the third strain gauge 113, as well as the consistency of deformation of the second strain gauge 112 and the fourth strain gauge 114.

[0034] This allows the initial potential difference e at the monitoring point to be brought to zero, which can further improve the linearity of the detection, improve the accuracy of the detection results, and achieve high-precision detection of minute displacements.

[0035] See Figure 1-3Optionally, the fixed support 2 is welded to the elastomer 1. In this embodiment, compared with integral molding, the method of welding the fixed support 2 after the annular opening can reduce processing costs and improve efficiency while ensuring structural consistency.

[0036] See Figure 1 , Figure 4 Optionally, the fixed support 2 is provided with a connecting groove 21, and the adapter 3 is detachably connected to the fixed support 2 through the connecting groove 21. In this embodiment, for the installation of displacement sensors when detecting overly complex spaces, the adapter 3 is used to fix the fixed support 2, which can effectively improve the applicability. The adapter 3 can be shaped according to the actual situation so that the sensor can avoid overly narrow spaces. Only the adapter 3 needs to be fixedly connected to the narrow space. The two fixed supports 2 are small and the distance between them is also small. Even with the adapter 3, the space required is relatively small, which can be applied to narrow spaces.

[0037] See Figure 4 Optionally, the adapter 3 includes a connecting part 31, a clearance part 32, and a fitting part 33. The fixed leg 2 is detachably connected to the connecting part 31. One end of the clearance part 32 is fixedly connected to the connecting part 31, and the other end is connected to the fitting part 33. The two fitting parts 33 are used to fix the connection on both sides of the crack. The fixed leg 2 is connected to the connecting part 31 by bolts. In this embodiment, the connecting part 31 is used to fix the fixed leg 2. The fitting part 33 straddles both sides of the crack and is fixed. The specific fixing method is the prior art and can be fixed according to actual needs. It can be welding or bolt connection. The clearance part 32 is used to make clearance. The main body of the clearance part 32 can be L-shaped to make clearance, so that the connecting part 31 can be exposed for the connection of the fixed leg 2. The structural features of the strain gauge submicron displacement sensor consist of a fixed support 2 and an elastic body 1, straddling both sides of the crack in the sample. The displacement causes the stress to be amplified in two stages by the elastic body 1 and concentrated on the top ring of the elastic body 1. The signal is detected by the strain gauge attached to it, and the detection result is obtained through external signal acquisition and processing equipment.

[0038] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A metal crack displacement sensor, characterized in that, The device includes an elastic body (1) and fixed legs (2). The elastic body (1) is an annular shape with an opening at the bottom. The two fixed legs (2) are fixedly connected to the two ends of the opening of the elastic body (1). The upper part of the elastic body (1) corresponding to the opening is configured as a strain zone (11). The strain zone (11) is fixedly connected to a first strain gauge (111), a second strain gauge (112), a third strain gauge (113), and a fourth strain gauge (114). The first strain gauge (111), the second strain gauge (112), the third strain gauge (113), and the fourth strain gauge (114) are connected in a full-bridge detection circuit.

2. A metal crack displacement sensor according to claim 1, characterized in that, The first strain gauge (111) and the third strain gauge (113) are fixedly connected to the upper end of the strain zone (11); the second strain gauge (112) and the fourth strain gauge (114) are fixedly connected to the lower end of the strain zone (11).

3. A metal crack displacement sensor according to claim 1, characterized in that, The structures of the elastic body (1) and the fixed support (2) are both symmetrical.

4. A metal crack displacement sensor according to claim 3, characterized in that, The first strain gauge (111) and the fourth strain gauge (114) have the same initial resistance, and the second strain gauge (112) and the third strain gauge (113) have the same initial resistance.

5. A metal crack displacement sensor according to claim 4, characterized in that, The initial resistance of the first strain gauge (111), the second strain gauge (112), the third strain gauge (113) and the fourth strain gauge (114) is 350 ohms and / or 750 ohms.

6. A metal crack displacement sensor according to claim 1, characterized in that, The fixed support (2) is welded to the elastomer (1).

7. A metal crack displacement sensor according to claim 1, characterized in that, The fixed support (2) has a connecting groove (21).

8. A metal crack displacement sensor according to claim 7, characterized in that, It also includes a transition tool (3), which is detachably connected to the fixed support leg (2) via a connecting groove (21).

9. A metal crack displacement sensor according to claim 8, characterized in that, The adapter (3) includes a connecting part (31), a relief part (32) and a fitting part (33). The fixed support (2) is detachably connected to the connecting part (31). One end of the relief part (32) is fixedly connected to the connecting part (31) and the other end is connected to the fitting part (33). The two fitting parts (33) are used to fix the connection on both sides of the crack.

10. A metal crack displacement sensor according to claim 9, characterized in that, The fixed support (2) and the connecting part (31) are connected by bolts.

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