A welding device for fiber optic strain sensors

Abstract

The utility model relates to strain sensor technical field, the utility model provides a kind of welding device of optical fiber strain sensor, including heating platform, the notched opening for the slot of limiting placement rhombus matrix is opened in heating platform, pad is equipped between heating platform and sliding block, pad is used to melt solder with the temperature conduction of heating platform to sliding block, and the temperature of heating platform can be conducted to rhombus matrix. Through the notched opening of heating platform sets slot and limits rhombus matrix, and through rhombus matrix and pad conduction heat and melt solder, realize the welding of optical fiber and rhombus matrix, ensure that welding position is accurate, solder is full and has no gap, to improve the accuracy of strain transmission and the stability of strain sensor.

Description

Technical Field

[0001] This utility model relates to the field of strain sensor technology, and more specifically, to a welding device for an optical fiber strain sensor. Background Technology

[0002] Fiber optic sensors, as intelligent devices that convert the state of a measured object into a measurable optical signal, are widely used for strain, displacement, and temperature detection due to their significant advantages such as resistance to electromagnetic interference, corrosion resistance, and high measurement accuracy. Their core working principle is as follows: a light beam emitted from a light source is transmitted through an optical fiber to a modulator. The measured parameter (such as strain, temperature, or pressure) is modulated by changing the optical properties of the light, such as wavelength, phase, and intensity, to form a modulated signal. This signal is then demodulated to achieve precise measurement of the physical quantity. For example, the fiber optic strain sensor disclosed in patent CN219284226U employs a structure where one end of a fiber optic grating is welded to a rhombic substrate and the other end is welded to a slider. After pre-stretching, the slider is then welded to the rhombic substrate.

[0003] Currently, some welding processes for fiber optic strain sensors still rely on adhesives to fix the fiber to the structural components. This method not only has insufficient bonding strength, but also easily leads to micro-displacement of the fiber due to adhesive creep during long-term use, resulting in zero-point drift of the sensor, distortion of measurement data, and seriously affecting product stability. Even if some processes use glass solder instead of adhesive for welding, there is still the problem of uneven heating of the glass solder during the fusion process. This often results in insufficient melting of the solder in some areas, forming gaps, or excessively high local temperatures that damage the fiber core, directly reducing product reliability and performance consistency in mass production. Utility Model Content

[0004] The purpose of this invention is to provide a welding device for fiber optic strain sensors, which solves the problems of low welding strength and insufficient reliability of existing fiber optic strain sensors.

[0005] This utility model is achieved through the following technical solution: a welding device for an optical fiber strain sensor, suitable for welding strain sensors. The strain sensor includes a rhombic substrate and an optical fiber. A slider is slidably connected to the rhombic substrate. One end of the optical fiber is welded to the slider by solder, and the other end of the optical fiber is welded to the rhombic substrate by solder. The welding device includes a heating table with a slot for limiting the placement of the rhombic substrate. A pad is provided between the heating table and the slider. The pad is used to conduct the temperature of the heating table to the slider to melt the solder, and the temperature of the heating table can be conducted to the rhombic substrate.

[0006] Furthermore, the heating stage includes a box body and a heating platform disposed within the box body for contacting the rhomboid substrate, the height of which is higher than the height of the box body's perimeter.

[0007] Furthermore, protective strips are provided on the top of the opposite two sides of the box, and the optical fiber is fixed to the protective strips with high-temperature tape.

[0008] Furthermore, the protective strip is made of bent aluminum alloy.

[0009] Furthermore, the edges of the protective strip have rounded corners.

[0010] Furthermore, the slots are respectively snapped into the optical fiber fixing ends at both ends of the rhombic substrate, and several slots are staggered along the length of the heating table.

[0011] Furthermore, the fixed ends of the optical fibers at both ends of the rhomboid substrate are suspended above the slot.

[0012] Furthermore, the rhomboid base, slider, and pad are all made of Invar steel.

[0013] This utility model has at least the following advantages and beneficial effects: by setting a slot-limiting rhomboid substrate on the heating table, and by conducting heat through the rhomboid substrate and the pad to melt the solder, the optical fiber and the rhomboid substrate are welded, ensuring accurate welding position and full solder without gaps, thereby improving the accuracy of strain transmission and the stability of the strain sensor. Attached Figure Description

[0014] Figure 1 A schematic diagram of the working state of a welding device for an optical fiber strain sensor provided by this utility model.

[0015] Figure 2 This utility model Figure 1 A magnified view of a portion of point A in the middle.

[0016] Figure 3 A cross-sectional view of a welding device for an optical fiber strain sensor provided by this utility model.

[0017] Figure 4 A schematic diagram of the heating stage in a welding device for an optical fiber strain sensor provided by this utility model.

[0018] Figure 5 A schematic diagram of the protective strip in a welding device for an optical fiber strain sensor provided by this utility model.

[0019] Reference numerals: 1-Rhombus-shaped substrate, 11-Slider, 12-Fiber optic fixing end, 13-Measuring fixing end, 2-Fiber optic, 3-Solder, 4-Heating platform, 40-Slot, 41-Box, 42-Heating platform, 43-Protective strip, 44-High temperature tape, 5-Padded block. Detailed Implementation

[0020] The specific implementation method is described below with reference to the accompanying drawings.

[0021] Example like Figures 1 to 5As shown, this embodiment mainly discloses a welding device for an optical fiber strain sensor, which is suitable for welding strain sensors. The strain sensor includes a rhombic substrate 1 and an optical fiber 2. A slider 11 is slidably connected to the rhombic substrate 1. One end of the optical fiber 2 is welded to the slider 11 through solder 3, and the other end of the optical fiber 2 is welded to the rhombic substrate 1 through solder 3. The welding device includes a heating table 4. The heating table 4 has a slot 40 for limiting the placement of the rhombic substrate 1. A pad 5 is provided between the heating table 4 and the slider 11. The pad 5 is used to conduct the temperature of the heating table 4 to the slider 11 to melt the solder 3, and the temperature of the heating table 4 can be conducted to the rhombic substrate 1. Specifically, the two ends of the long diagonal of the rhombus-shaped substrate 1 are fixed ends 12 for optical fibers 2, and each end has a slot for the optical fiber 2 to pass through. One end of the slot has a groove for placing solder 3, and the other end has a sliding block 11 connected to the slot. The sliding block 11 has a through groove for the optical fiber 2 to pass through and a groove for placing solder 3. The two ends of the short diagonal of the rhombus-shaped substrate 1 are measuring and fixing ends 13 for connecting the object to be measured. A rhombus-shaped hole is formed in the middle of the rhombus-shaped substrate 1, and the thickness of the rhombus-shaped substrate 1 is equal around the rhombus-shaped hole. The heating stage 4 is temperature controlled by PID. The heating principle and heating structure can adopt existing technology, which is known to those skilled in the art and will not be described in detail here. By setting a slot 40 on the heating stage 4 to limit the rhombic substrate 1, precise positioning of the rhombic substrate 1 during the welding process is achieved, avoiding deviations in the welding position of the optical fiber 2, the rhombic substrate 1, and the slider 11 due to displacement of the rhombic substrate 1. The accuracy of the welding position directly determines the accuracy of the subsequent sensor strain transmission, effectively preventing distortion of strain measurement data caused by positional deviation. The pad 5 added between the heating stage 4 and the slider 11 can efficiently conduct the heat of the heating stage 4 to the slider 11. The solder 3 uses glass powder with a melting point of 350℃, while the core material of the optical fiber 2 is quartz glass (mainly composed of silicon dioxide, SiO2), with a melting point of approximately 1713℃. This ensures that the solder 3 can firmly connect the optical fiber 2 and the rhombic substrate 1, while effectively preventing damage to the optical fiber 2 from the high temperature of the heating stage 4. In use, after assembling the slider 11 with the rhombus-shaped base 1, place it on the heating platform 4, and put the pad 5 into the rhombus-shaped hole of the rhombus-shaped base 1, abutting against the acute edge of one end of the slider 11 in the rhombus-shaped hole. The part of the slider 11 suspended in the rhombus-shaped hole rests on the pad 5. After mixing the solder 3 with water, place it in the material tank, turn on the heating platform 4, and set the temperature of the heating platform 4 to 350℃ (the temperature can be appropriately increased to consider heat loss). The solder 3 is melted through heat conduction between the rhombus-shaped base 1 and the pad 5. After the temperature reaches 350℃, keep it for 2 to 3 minutes to allow the solder 3 to melt completely. At the same time, use a tool (such as the back of a file) to repeatedly press the solder 3 to make the solder 3 fill the material tank completely and ensure that there are no gaps. Then turn off the heating platform 4 and wait for it to cool naturally. When the temperature of the heating platform 4 is at room temperature, the welded strain sensor can be removed.

[0022] Furthermore, in specific implementation, such as Figure 1 As shown, the heating platform 4 provided in this embodiment of the present invention includes a housing 41 and a heating platform 42 disposed within the housing 41 for contacting the rhomboid substrate 1. The height of the heating platform 42 is higher than the height of the surrounding area of ​​the housing 41. Specifically, the surrounding area of ​​the housing 41 is lower than the heating platform 42 to prevent the portion of the optical fiber 2 extending to the outside of the heating platform 4 from contacting the high-temperature heating area, and to prevent the coating or core of the optical fiber 2 from being damaged due to excessive heat.

[0023] Furthermore, in a specific implementation, protective strips 43 are provided on the top of the opposite sides of the box 41 provided in this embodiment of the present invention, and the optical fiber 2 is fixed to the protective strips 43 by high-temperature tape 44. Specifically, the protective strips 43 provide a stable support carrier for the optical fiber 2, and the two ends of the optical fiber 2 are respectively fixed to the corresponding protective strips 43 by the high-temperature tape 44, which can keep the optical fiber 2 in a straight state at all times, ensure that the grid area of ​​the optical fiber 2 is accurately located at the center of the hollow rhombus of the rhombus substrate 1, prevent uneven stress after welding due to the slack of the optical fiber 2, thereby avoiding nonlinear errors in the strain transmission process, improving the measurement accuracy of the sensor, and also ensuring the consistency of the positioning of the optical fiber 2 in batch welding.

[0024] Furthermore, in specific implementations, the protective strip 43 provided in this embodiment of the present invention is made of bent aluminum alloy. Aluminum alloy has good mechanical strength and toughness, and can be easily made into a structure that fits the side of the box 41, and can be detachably connected to the box 41 by bolts.

[0025] Furthermore, in specific implementations, the edges of the protective strip 43 provided in this embodiment of the present invention are rounded. The rounded corners eliminate the sharp edges of the protective strip 43, preventing scratches even if the optical fiber 2 makes slight contact with the edge of the protective strip 43 during fixing or welding. This avoids increased optical loss or even breakage of the optical fiber 2 due to cracks or damage on its surface, further ensuring the integrity of the optical fiber 2.

[0026] Furthermore, in specific implementation, the slots 40 provided in this embodiment of the present invention are respectively engaged with the fixed ends 12 of the optical fibers 2 at both ends of the rhombic substrate 1, and several slots 40 are staggered along the length of the heating table 4. Specifically, the positioning of one rhombic substrate 1 requires two corresponding slots 40. The rhombic surface of the rhombic substrate 1 rests on the table surface of the heating table 4, while the fixed ends 12 of the optical fibers 2 of the rhombic substrate 1 are positioned in the slots 40 to firmly fix the rhombic substrate 1 and prevent the rhombic substrate 1 from shifting during the welding process. The staggered arrangement of the slots 40 along the length of the heating table 4 can make full use of the heating area space of the heating table 4, shorten the batch welding time, and reduce the production time cost per unit product.

[0027] Furthermore, in specific implementation, such as Figure 3 As shown, in this embodiment of the invention, the fixed ends 12 of the optical fibers 2 at both ends of the rhombic substrate 1 are suspended above the slot 40. This suspended state prevents the fixed ends 12 of the optical fibers 2 from directly contacting the heating platform 4, thus avoiding the absorption of heat from the heating platform 42 by the fixed ends 12 of the optical fibers 2. This does not affect the temperature at the material tank and ensures that the heat from the heating platform 4 is concentrated only on the middle welding area of ​​the rhombic substrate 1.

[0028] Furthermore, in specific implementations, the rhomboid base 1, slider 11, and pad 5 provided in this embodiment of the present invention are all made of Invar steel. Invar steel (i.e., 4J36 alloy, a nickel-iron alloy containing approximately 36% nickel) is a low-expansion alloy, and its melting point is typically between 1430℃ and 1450℃. The rhomboid base 1, slider 11, and pad 5 are designed with the same material, ensuring that the thermal conductivity of the three is completely consistent. This avoids the problem of asynchronous melting of the solder 3 caused by differences in the thermal conductivity of different materials, ensuring that the solder 3 at the rhomboid base 1 and slider 11 can reach the melting point simultaneously, reducing defects such as solder voids and incomplete welds, and significantly improving the weld strength.

Claims

1. A welding apparatus for an optical fiber strain sensor, suitable for welding strain sensors, the strain sensor comprising a rhombic substrate (1) and an optical fiber (2), wherein a slider (11) is slidably connected to the rhombic substrate (1), one end of the optical fiber (2) is welded to the slider (11) by solder (3), and the other end of the optical fiber (2) is welded to the rhombic substrate (1) by solder (3), characterized in that, The welding device includes a heating table (4), on which a slot (40) is provided for limiting the placement of the rhombic substrate (1). A pad (5) is provided between the heating table (4) and the slider (11). The pad (5) is used to conduct the temperature of the heating table (4) to the slider (11) to melt the solder (3), and the temperature of the heating table (4) can be conducted to the rhombic substrate (1).

2. The welding apparatus for an optical fiber strain sensor according to claim 1, characterized in that, The heating platform (4) includes a box (41) and a heating platform (42) disposed inside the box (41) for contacting the rhomboid substrate (1). The height of the heating platform (42) is higher than the height of the box (41) around its perimeter.

3. The welding apparatus for an optical fiber strain sensor according to claim 2, characterized in that, The box body (41) has protective strips (43) on the top of its two opposite sides, and the optical fiber (2) is fixed to the protective strips (43) by high temperature tape (44).

4. The welding apparatus for an optical fiber strain sensor according to claim 3, characterized in that, The protective strip (43) is made of aluminum alloy bent into shape.

5. The welding apparatus for an optical fiber strain sensor according to claim 3, characterized in that, The edge of the protective strip (43) is rounded.

6. The welding apparatus for an optical fiber strain sensor according to claim 1, characterized in that, The slots (40) are respectively engaged with the fixed ends (12) of the optical fibers (2) at both ends of the rhombic substrate (1), and several slots (40) are staggered along the length of the heating table (4).

7. The welding apparatus for an optical fiber strain sensor according to claim 6, characterized in that, The fixed ends (12) of the optical fibers (2) at both ends of the rhombic substrate (1) are suspended above the slot (40).

8. The welding apparatus for an optical fiber strain sensor according to claim 1, characterized in that, The rhomboid base (1), the slider (11), and the pad (5) are all made of Invar steel.

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