A device and method for sticking a strain gauge in a small-diameter pipe

Abstract

The application discloses a small-diameter pipe internal strain gauge sticking device and sticking method, and belongs to the field of resistance strain testing. The sticking device comprises a positioning sleeve, a positioning pipe clamp capable of being positioned and sliding outside the positioning sleeve, an auxiliary push rod connected slidingly in the positioning sleeve, and a push-out sleeve head located at the end of the positioning sleeve. The positioning pipe clamp is provided with a plurality of positioning scales uniformly distributed around the circumference thereof, each of the positioning scales is marked with a scale line and is sleeved with a positioning buckle. The end of the auxiliary push rod extending into the positioning sleeve is provided with a screw rod, and the push-out sleeve head is connected to one end of the positioning sleeve. The push-out sleeve head comprises at least one strain gauge sticking push block arranged on the circumference thereof and capable of extending and contracting radially. The strain gauge sticking push block is movably connected to the screw rod. When the auxiliary push rod is pressed, the strain gauge sticking push block is pushed out radially and outwardly from the push-out sleeve head. The device can install the strain gauge to a specified angle and position in the small-diameter pipe, improves the sticking precision of the strain gauge, and thus makes the collected data more accurate.

Description

Technical Field

[0001] This invention belongs to the field of resistance strain testing, and particularly relates to a device and method for attaching strain gauges inside a small-diameter pipe. Background Technology

[0002] Strain gauges are elements used to measure strain, consisting of sensitive grids and other components. They come in various forms, with wire and foil types being the most common. The working principle of resistance strain gauges is based on the strain effect. When a material undergoes mechanical deformation under external loads or environmental conditions, the strain gauge amplifies the numerous minute deformations generated during the test into a larger deformation, causing a corresponding change in its resistance value. This change can be visually measured using specialized testing instruments, and the mechanical deformation strain of the tested component can be calculated using formulas. Strain gauges effectively reflect the physical and geometric properties of conductors and are widely used in research on material failure and fatigue testing.

[0003] Currently, in most experiments, strain gauges are attached to the outside of the specimen, requiring only simple manual handling and hand-application to achieve good adhesion. However, for experiments involving more complex specimens or operating conditions, more precise experimental data is needed, thus requiring strain gauges to be attached inside the pipe. To obtain strain data in different directions, the attachment angle of the strain gauge may be 45°, 90°, or 180° circumferentially. The positioning and angle of the strain gauge attachment have a significant impact on experimental data and sensor accuracy, thus affecting the overall experimental results. Especially for experimental specimens with small pipe diameters (less than 30cm), it is difficult to insert hands into the pipe for attachment, and visibility is poor. Even with the use of long clamps to assist attachment, misalignment of the strain gauge is common, resulting in significant errors from the expected positioning. However, there is currently a lack of specialized equipment for the positioning and attachment of strain gauges inside pipes. Therefore, proposing a convenient, efficient, and highly accurate small-diameter pipe strain gauge attachment device and its application method suitable for various operating conditions has become a pressing technical problem to be solved in this field. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a small-diameter strain gauge bonding device and bonding method, aiming to solve or improve at least one of the aforementioned technical problems.

[0005] To achieve the above objectives, in one aspect, the present invention provides a small-diameter strain gauge bonding device, comprising a positioning sleeve, a positioning clamp slidably positioned outside the positioning sleeve along the axial direction, an auxiliary push rod slidably connected inside the positioning sleeve along the axial direction, and a push-out head located at the end of the positioning sleeve; the positioning clamp has a plurality of positioning scales evenly distributed around its circumference, each positioning scale being marked with a scale line and fitted with a positioning buckle; one end of the auxiliary push rod extending into the positioning sleeve is provided with a screw; the push-out head is connected to one end of the positioning sleeve, and the push-out head includes at least one strain gauge bonding push block disposed on its circumference and movable radially, the strain gauge bonding push block being movably connected to the screw; pressing the auxiliary push rod, the strain gauge bonding push block is pushed outward radially along the push-out head.

[0006] The above structure aims to propose a strain gauge bonding device for small-diameter pipes, which solves the problem of the difficulty in bonding strain gauges inside workpieces with small diameters. It can also install strain gauges at specified angle positions under different working conditions, improving the bonding accuracy of strain gauges and thus making the collected data more accurate. It has significant engineering value and significance.

[0007] Preferably, the ejector head further includes a pusher base and a wedge-shaped pusher. The pusher base is connected to one end of the positioning sleeve, and the wedge-shaped pusher is located in the inner cavity of the pusher base and elastically connected to it. The screw extends into the inner cavity of the pusher base and connects with the wedge-shaped pusher. The side of the wedge-shaped pusher is provided with at least one wedge-shaped inclined surface, and the inner side of the strain gauge adhesive pusher is provided with an inclined surface that cooperates with the wedge-shaped inclined surface. This preferred embodiment proposes a specific structure in which the inclined surface can convert the axial linear movement of the wedge-shaped pusher into the radial linear movement of the strain gauge adhesive pusher, that is, it can make the strain gauge adhesive pusher extend radially outward under the push of the wedge-shaped pusher.

[0008] Preferably, two strain gauge adhesive pushers are provided, symmetrically arranged on two sides of the wedge-shaped pusher. Each side of the wedge-shaped pusher near the strain gauge adhesive pusher has a wedge-shaped inclined surface, and a third spring connects the two strain gauge adhesive pushers. In this preferred structure, the two strain gauge adhesive pushers are respectively arranged on opposite sides, enabling selection of the strain gauge adhesive position in a 90° direction. It should be understood that when the two strain gauge adhesive pushers are set at different included angles, other adhesive position selection angles can be achieved.

[0009] Preferably, the outer surface of the strain gauge adhesive pusher is shaped to fit the internal dimensions of the tube (e.g., a semi-circular surface) and has a cross-shaped strain gauge groove. The non-adhesive surface of the strain gauge is pushed into the strain gauge groove, allowing the strain gauge to be better fixed to the strain gauge adhesive pusher.

[0010] Preferably, the strain gauge adhesive pusher is made of rubber, and the strain gauge groove (19) narrows in the middle to secure the strain gauge. The rubber strain gauge adhesive pusher can better fit the inner wall of the pipe and can deform.

[0011] Preferably, the ejector sleeve is detachably connected to one end of the positioning sleeve. In practical applications, different ejector sleeves with different outer diameters are required depending on the inner diameter of the target pipe fitting. Setting the ejector sleeve to be detachably connected makes the positioning sleeve more versatile. When using it, only the corresponding model of ejector sleeve needs to be replaced, which is convenient and low-cost.

[0012] Preferably, the positioning sleeve is marked with scale lines. This facilitates the vertical positioning of the insertion depth of the sleeve, providing an intuitive and convenient function for applications requiring adhesive application at a specific location.

[0013] Preferably, the positioning clamp includes a clamp, the positioning ruler is fixed to the periphery of the clamp, and a notch is provided on one side of the clamp. A limiting bolt is connected to the notch, and the clamp is adjusted in position and fastened to the outside of the positioning sleeve by the limiting bolt. By changing the connection position between the positioning clamp and the positioning sleeve, the bonding depth can be adjusted, enabling the bonding device to meet the bonding needs of various positions.

[0014] Preferably, the inner side of the positioning sleeve has two axially oriented limiting grooves, the auxiliary push rod is provided with a limiting slider that cooperates with the limiting grooves, and the bottom of the limiting groove is also provided with a first spring to assist the auxiliary push rod in resetting.

[0015] Compared with the prior art, the adhesive device of the present invention has the following advantages and technical effects: the adhesive device is simple to operate, has high working efficiency, and low cost. The components are simple and convenient to connect, the purely mechanical operation requires no electricity, and the wear of the ejector head is small, allowing for reuse.

[0016] In another aspect, the present invention also provides a method for attaching strain gauges inside a small-diameter pipe, using the strain gauge attachment device described in any of the above claims, comprising the following steps:

[0017] S1. Select a matching adhesive device for the ejector sleeve based on the internal dimensions and shape of the target pipe fitting;

[0018] S2. Adjust the positioning tube clamp to the corresponding height according to the scale lines;

[0019] S3. Apply adhesive to the contact surface between the strain gauge and the pipe fitting, and then load it onto the bonding device;

[0020] S4. Insert the adhesive device into the target pipe fitting, center it using a positioning ruler, and position it using the positioning clips.

[0021] S5. Press the auxiliary push rod to push out the strain gauge adhesive push block loaded with strain gauges, so that the strain gauges contact and adhere to the inner wall of the target pipe fitting;

[0022] S6. Continue pressing the auxiliary push rod while rotating the adhesive device to ensure that the strain gauge is fully bonded to the inner wall of the target pipe. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the small-diameter pipe strain gauge bonding device of the present invention;

[0025] Figure 2 This is a diagram showing the positional relationship between the positioning ruler and the pipe clamp in the device of the present invention;

[0026] Figure 3 This is a partial cross-sectional view of the positioning sleeve and auxiliary push rod in the device of the present invention;

[0027] Figure 4 This is an exploded view of the device of the present invention, showing the extension of the sleeve.

[0028] Figure 5 This is a schematic diagram of the operation of the device of the present invention;

[0029] Figure 6 This is a schematic diagram of three different models of the ejector head in the device of the present invention.

[0030] The components include: 1. Positioning pipe clamp; 2. Positioning sleeve; 3. Auxiliary push rod; 4. Push-out sleeve; 4a. Type I sleeve; 4b. Type II sleeve; 4c. Type III sleeve; 5. Positioning buckle; 6. Pipe clamp; 7. Positioning ruler; 8. Limiting bolt; 9. Screw; 10. Limiting slide groove; 11. First spring; 12. Limiting slider; 13. Push head base; 14. Wedge-shaped push head; 15. Strain gauge adhesive push block; 16. Wedge-shaped bottom groove; 17. Second spring; 18. Third spring; 19. Strain gauge groove. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1:

[0034] The following is combined with Figures 1-6 The present invention describes a small-diameter strain gauge bonding device for pipes.

[0035] refer to Figure 1 , Figure 1 A schematic diagram of a small-diameter strain gauge bonding device according to Embodiment 1 of the present invention is shown. The bonding device includes a positioning clamp 1, a positioning sleeve 2 connected inside the positioning clamp 1, an auxiliary push rod 3 slidably connected to the positioning sleeve 2 along the axial direction of the positioning sleeve 2, and a push-out head 4 connected to the bottom end of the auxiliary push rod 3 and the positioning sleeve 2.

[0036] Specifically, the positioning sleeve 2 is a hollow cylindrical sleeve with graduations marked on its body. Two symmetrical protrusions protrude axially (in the length direction of the positioning sleeve 2) on the outer side of the sleeve. Two axial limiting grooves 10 are opened on the inner side of the sleeve. The protrusions are used to radially limit the positioning clamp 1, so that the positioning clamp 1 can only slide back and forth along the axial direction of the positioning sleeve 2. The limiting grooves 10 on the inner side of the positioning sleeve 2 are used to cooperate with the two limiting sliders 12 on the outer side of the auxiliary push rod 3 to form a sliding connection. A first spring 11 is also provided at the bottom of the limiting grooves 10. The first spring 11 is used to assist the push rod 3 in resetting.

[0037] Specifically, such as Figure 2 As shown, the positioning pipe clamp 1 consists of a pipe clamp 6 and a positioning ruler 7. The pipe clamp 6 has a bayonet on one side, with a hole for the limiting bolt 8 to pass through. The limiting bolt 8 is fastened to the bayonet hole. The pipe clamp 6 has two symmetrical longitudinal sliding grooves on its inner side. The protrusion on the outer side of the positioning sleeve 2 is connected to the longitudinal sliding groove, allowing the two to slide against each other. The positioning ruler 7 is set in multiple (at least three) and is evenly distributed around the outside of the pipe clamp 6. Each positioning ruler 7 is marked with a scale line. The center of the target pipe fitting can be accurately positioned using multiple positioning rulers 7, so that the adhesive device can be installed at the center of the pipe opening of the target pipe fitting. Each positioning ruler 7 is fitted with a positioning buckle 5 on its periphery. The positioning buckle 5 is a square ring that fits on the positioning ruler 7 and can slide back and forth along the axial direction of the positioning ruler 7.

[0038] In one specific embodiment, four positioning rulers 7 are evenly distributed along the circumference, forming a cross-shaped positioning ruler 7.

[0039] Specifically, such as Figure 3As shown, the auxiliary push rod 3 is slidably inserted into the positioning sleeve 2. Two limiting sliders 12 are located on the outer side of the auxiliary push rod 3. The limiting sliders 12 connect with the limiting grooves 10 on the inner side of the positioning sleeve 2, forming a limiting sliding fit, and are located at the top of the first spring 11. A screw 9 is provided at the bottom of the auxiliary push rod 3, and the end of the screw 9 has external threads for threaded connection to the push-out sleeve 4. Preferably, the auxiliary push rod 3 has a square rod structure.

[0040] Specifically, such as Figure 4 As shown, the ejector head 4 is located at the end of the positioning sleeve 2 and is threadedly connected to the auxiliary push rod 3. The ejector head 4 includes a pusher base 13, a wedge-shaped pusher head 14, and a strain gauge bonding pusher block 15. The pusher base 13 is integrally formed with a through hole at the top to accommodate the screw 9. A wedge-shaped bottom groove 16 is formed inside, and a second spring 17 is provided in the wedge-shaped bottom groove 16 for resetting the wedge-shaped pusher head 14. The top of the pusher base 13 is fixedly connected to one end of the positioning sleeve 2. The screw 9 at the bottom of the auxiliary push rod 3 passes through the through hole at the top of the pusher base 13 and connects to the wedge-shaped pusher head 14. Specifically, a threaded hole is formed in the center of the top of the wedge-shaped pusher head 14, and the position of this threaded hole coincides axially with the position of the through hole. 9. After passing through the through hole, the threaded connection is made to the threaded hole, so that the wedge-shaped push head 14 is connected to the auxiliary push rod 3 and used in conjunction. The bottom of the wedge-shaped push head 14 is connected to the second spring 17. When the auxiliary push rod 3 is pushed, the second spring 17 is compressed and deformed, and the wedge-shaped push head 14 moves towards the bottom of the wedge-shaped bottom groove 16. The strain gauge adhesive push blocks 15 are connected to the two outer sides of the wedge-shaped push head 14. The two strain gauge adhesive push blocks 15 are connected by two third springs 18. The two third springs 18 are located on both sides of the wedge-shaped push head 14. The inner side of the strain gauge adhesive push block 15 abuts against the outer side of the wedge-shaped push head 14, and the abutting surface is set as an inclined surface adapted to the wedge-shaped push head 14, specifically as follows. Figure 4 As shown, the inner side of the strain gauge adhesive pusher 15 has an inclined groove to accommodate the wedge-shaped pusher 14. The inclined groove has an inclined surface that abuts against the outer side of the wedge-shaped pusher 14. This inclined surface can convert the axial linear movement of the wedge-shaped pusher 14 into the radial linear movement of the strain gauge adhesive pusher 15, that is, it can make the strain gauge adhesive pusher 15 extend radially outward under the push of the wedge-shaped pusher 14. Two third springs 18 provide a rebound force to reset the two strain gauge adhesive pushers 15. The outer side of the strain gauge adhesive pusher 15 has a strain gauge groove 19. The strain gauge groove 19 narrows in the middle, pushing the non-adhesive surface of the strain gauge into the strain gauge groove 19, so that the strain gauge can be better fixed on the strain gauge adhesive pusher 15. It should be understood that without the strain gauge groove 19, the strain gauge can also be fixed by dispensing or other methods.

[0041] Further optimization of the design: the strain gauge adhesive pusher 15 is a semi-cylindrical pusher, which is more suitable for internal adhesive application in round tubular fittings. It should be understood that in other non-circular tubular fitting applications, the strain gauge adhesive pusher 15 can be set to the same shape as the inner wall of the fitting. For example, in square tubular fittings, the strain gauge adhesive pusher 15 is a flat pusher, and in other irregularly shaped fittings, the strain gauge adhesive pusher 15 can also be an elliptical pusher, a spherical pusher, etc., without further limitation.

[0042] Further optimization of the design: the strain gauge bonding pusher 15 is made of rubber, which can generate a certain amount of deformation, resulting in a better bonding effect.

[0043] The design has been further optimized, with strain gauge groove 19 being a star-shaped groove, which is beneficial for adapting to the bonding of strain gauges from multiple directions and angles.

[0044] In a further optimized design, the ejector head 4 and the positioning sleeve 2 are detachably connected; the ejector head 4 can be replaced according to different workpiece diameters, such as... Figure 6 As shown, for the purpose of distinguishing descriptions, the definition is... Figure 6 (1) The ejector head is a type I ejector head 4a. Figure 6 (2) The ejector head is a type II ejector head 4b. Figure 6 (3) The ejector head is a type III ejector head 4c; among them, type I ejector head 4a is used with workpieces with a pipe diameter of 5-10cm, type II ejector head 4b is used with workpieces with a pipe diameter of 11-20cm, and type III ejector head 4c is used with workpieces with a pipe diameter of 21-30cm.

[0045] Working principle and effects of embodiments of the present invention:

[0046] like Figure 5 As shown, using the small-diameter pipe strain gauge pasting device of this embodiment, the target pipe is placed vertically and stably on the operating platform. A suitable push-out sleeve 4 is connected to the screw 9. Based on the scale lines on the outside of the positioning sleeve 2, the limiting bolt 8 is adjusted and the positioning sleeve 2 is slid longitudinally so that the strain gauge groove 19 corresponds to the pasting height. The limiting bolt 8 is tightened to lock it longitudinally. Then, two strain gauges with adhesive applied to one side are placed into the strain gauge groove 19 at the required pasting angle with the adhesive side facing outwards. The device is vertically placed inside the target pipe. The positioning clamp 1 is placed at the pipe opening for centering. The positioning buckle 5 is pushed horizontally into the target pipe for horizontal locking. The auxiliary push rod 3 is pressed vertically to push the strain gauge pasting push block 15 out to contact the inner wall of the target pipe. The pressing pressure is increased to first paste part of the strain gauge onto the inner wall of the pipe. While maintaining the pressure, the device is rotated horizontally clockwise and counterclockwise to fully paste the strain gauge onto the inner wall of the pipe, completing the target work.

[0047] Compared with existing technologies, the present invention has the following advantages and technical effects: The present invention is simple to operate, highly efficient, and low in cost. The components are easy to connect, the purely mechanical operation requires no electricity, and the pusher head suffers minimal wear and tear and can be reused.

[0048] The present invention has a wide working range. By changing the ejector sleeve of different sizes, strain gauges can be pasted into target pipes of different diameters. At the same time, the ejector sleeve also has four directions of strain gauge slot selection: 0°, 45°, 90° and 135°. It can also be centered and locked by positioning tube clamp. The positioning sleeve can be adjusted to different pasting heights according to actual requirements. All of the above can meet different working angles, heights and pipe diameters.

[0049] This invention not only solves the problem of small-diameter specimens that are inaccessible to human hands, reducing the errors caused by traditional manual bonding of strain gauges, but also reduces the problem of poor visibility inside the tube, improving positioning accuracy, thereby improving the bonding efficiency and quality of strain gauges, and enabling mass production in factories.

[0050] Example 2:

[0051] The following is combined with Figure 5 The present invention describes a method for attaching strain gauges inside a small-diameter pipe.

[0052] Embodiment 2 of the present invention proposes a method for attaching strain gauges inside small-diameter pipes, using the strain gauge attachment device for small-diameter pipes described in Embodiment 1 above, including the following steps:

[0053] S1. Select the appropriate size and shape of the ejector sleeve 4 according to the internal size and shape of the target pipe fitting, pinch the strain gauges on both sides and stick the push block 15, pass the screw 9 at the bottom of the auxiliary push rod 3 through the through hole at the top of the push head base 13 and screw it into the threaded hole of the wedge push head 14 to complete the connection between the auxiliary push rod 3 and the ejector sleeve 4.

[0054] S2. Adjust the positioning tube clamp 1 to the corresponding height according to the scale lines;

[0055] S3. Apply glue to the contact surfaces of the two strain gauges and the pipe fitting, select the required bonding angle, and load them onto the bonding device.

[0056] S4. First, place the pipe fitting vertically, then insert the adhesive device into the pipe fitting, and position the pipe clamp 1 at the pipe opening. Use the positioning ruler 7 for centering. Then push the positioning buckle 5 towards the pipe fitting for horizontal positioning and locking.

[0057] S5. Press the auxiliary push rod 3 to push out the strain gauge adhesive push blocks 15 on both sides until the strain gauge adhesive push blocks 15 contact and adhere to the inner wall of the pipe.

[0058] S6. Continue to apply pressure to make the strain gauge adhesive pusher 15 adhere tightly to the inner wall of the pipe. First, partially adhere the strain gauge to the inner wall of the pipe and keep it in a tight position. Then, rotate the adhesive device and use the deformation of the strain gauge adhesive pusher 15 to make the strain gauge fully adhere to the inner wall of the pipe.

[0059] The technical effects and advantages of Example 2 are detailed in the description of the working principle and technical effects of the small-diameter pipe strain gauge bonding device in Example 1, and will not be repeated here.

[0060] All aspects not detailed in this invention are conventional technical means known to those skilled in the art.

[0061] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "axial", "radial", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, 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 this invention.

[0062] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A device for attaching strain gauges inside a small-diameter pipe, characterized in that, The system includes a positioning sleeve (2), a positioning clamp (1) that can slide axially outside the positioning sleeve (2), an auxiliary push rod (3) that slides axially inside the positioning sleeve (2), and a push-out head (4) located at the end of the positioning sleeve (2). The positioning clamp (1) has multiple positioning scales (7) evenly distributed around its periphery, each of which is marked with a scale line and fitted with a positioning buckle (5). The auxiliary push rod (3) has a screw (9) at one end that extends into the positioning sleeve (2). The push-out head (4) is connected to one end of the positioning sleeve (2), and the push-out head (4) includes a push-out base (13), a wedge-shaped push-out (14), and two strain gauge adhesive push blocks (15) symmetrically arranged around its periphery and movable radially. The pusher base (13) is connected to one end of the positioning sleeve (2). The wedge-shaped pusher (14) is located in the inner cavity of the pusher base (13) and is elastically connected to it. The screw (9) extends into the inner cavity of the pusher base (13) and connects with the wedge-shaped pusher (14). The strain gauge adhesive push block (15) is movably connected to the screw (9). When the auxiliary push rod (3) is pressed, the strain gauge adhesive push block (15) is pushed outward along the radial direction of the push-out sleeve (4). The wedge-shaped pusher (14) has wedge-shaped inclined surfaces on both sides near the strain gauge adhesive push block (15). The inner side of the strain gauge adhesive push block (15) has an inclined surface that cooperates with the wedge-shaped inclined surface. A third spring (18) is connected between the two strain gauge adhesive push blocks (15).

2. The small-diameter pipe strain gauge bonding device according to claim 1, characterized in that, The outer surface of the strain gauge adhesive pusher (15) is adapted to the internal size and shape of the tube and is provided with a cross-shaped strain gauge groove (19).

3. The small-diameter pipe strain gauge bonding device according to claim 2, characterized in that, The strain gauge adhesive pusher (15) is made of rubber, and the strain gauge groove (19) narrows in the middle to clamp the strain gauge.

4. The small-diameter pipe strain gauge bonding device according to claim 1, characterized in that, The ejector head (4) is detachably connected to one end of the positioning sleeve (2).

5. The small-diameter pipe strain gauge bonding device according to claim 1, characterized in that, The positioning sleeve (2) is marked with scale lines.

6. The small-diameter pipe strain gauge bonding device according to claim 1, characterized in that, The positioning clamp (1) includes a clamp (6), the positioning ruler (7) is fixed to the periphery of the clamp (6), the clamp (6) has a slot on one side, and a limiting bolt (8) is connected to the slot. The clamp (6) is adjusted and fastened to the outside of the positioning sleeve (2) by the limiting bolt (8).

7. The small-diameter pipe strain gauge bonding device according to claim 1, characterized in that, The positioning sleeve (2) has two axially oriented limiting grooves (10) on its inner side. The auxiliary push rod (3) is provided with a limiting slider (12) that cooperates with the limiting grooves (10). The bottom of the limiting grooves (10) is also provided with a first spring (11) to assist the auxiliary push rod (3) in resetting.

8. A method for attaching strain gauges inside a small-diameter pipe, characterized in that, Using the small-diameter pipe strain gauge bonding device as described in any one of claims 1 to 7, the bonding is performed using the following steps: S1. Select the appropriate adhesive device for the ejector sleeve (4) according to the internal dimensions and shape of the target pipe fitting; S2. Adjust the positioning clamp (1) to the corresponding height according to the scale line; S3. Apply adhesive to the contact surface between the strain gauge and the pipe fitting, and then load it onto the bonding device; S4. Insert the pasting device into the target pipe fitting and use the positioning ruler (7) for centering and the positioning buckle (5) for positioning. S5. Press the auxiliary push rod (3) to push out the strain gauge adhesive push block (15) loaded with strain gauges, so that the strain gauges contact and adhere to the inner wall of the target pipe. S6. Continue to press the auxiliary push rod (3) while rotating the adhesive device to ensure that the strain gauge is fully bonded to the inner wall of the target pipe.

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