Small frameless optical fiber ring assembly capable of reducing stress and preparation method thereof

Abstract

The invention discloses a small frameless optical fiber ring assembly capable of reducing stress and a preparation method thereof, and solves the problems that extra stress is generated in the fixing process of a frameless optical fiber ring and a support, and the size is increased after a magnetic shielding outer cover is additionally arranged. The invention discloses a small frameless optical fiber ring assembly capable of reducing stress. The small frameless optical fiber ring assembly comprises an optical fiber ring support made of a soft magnetic alloy material, an annular cover plate and a frameless optical fiber ring, the optical fiber ring support is of an integrally-formed circular-ring-shaped structure with an opening in one end, and a containing cavity is defined by a bottom wall, a first vertical wall and a second vertical wall. The first vertical wall is provided with a fiber outlet hole, the second vertical wall is provided with a circular mounting table, the mounting table is provided with a mounting hole, and the bottom wall is provided with a groove used for accommodating an optical fiber ring exchange layer; the open end of the optical fiber ring bracket is connected with a cover plate; and the frameless optical fiber ring is arranged in the accommodating chamber, is matched with the bottom wall and then is adhered to the bottom wall, and the other wall surfaces are in clearance fit with the inner wall surface of the optical fiber ring bracket and the cover plate.

Description

Technical Field

[0001] This invention relates to fiber optic ring assemblies, and more specifically to a small, frameless fiber optic ring assembly with reduced stress and its fabrication method. Background Technology

[0002] Fiber optic gyroscopes are all-solid-state optoelectronic inertial instruments with advantages such as no moving parts, low cost, shock resistance, high sensitivity, long lifespan, large dynamic range, short startup time, and wide accuracy coverage, leading to their widespread application in various fields. The working principle of a fiber optic gyroscope utilizes the Sagnac effect to detect angular velocity. The detection of the Sagnac effect originates from the interference phase between two counter-propagating light waves in a fiber optic loop; therefore, the fiber optic loop is the core component of the fiber optic gyroscope that senses angular velocity.

[0003] An optical fiber ring is a circular structure formed by winding a single optical fiber layer by layer using a specific method. The diameter of an optical fiber ring typically ranges from 30mm to 90mm, but the fiber length can reach hundreds or even thousands of meters. Optical fiber rings are used in both framed and frameless configurations, with frameless rings being more widely used due to their superior performance. The detection light wave of a fiber optic gyroscope needs to pass through the optical fiber ring for interference, and the stability of the optical fiber ring is crucial to the accuracy of the gyroscope's detection. Generally, after the frameless optical fiber ring is wound, it is fixed to the gyroscope using a bracket. This method maintains the all-solid-state structure of traditional fiber optic gyroscopes, ensuring that the gyroscope will not experience significant output signal drift under strong vibration and shock environments. However, during the fixing process of the frameless optical fiber ring to the bracket, additional fixing points are needed on the optical fiber ring to maintain stability. This generates additional stress on the optical fiber ring, affecting its optical properties and reducing the accuracy of the fiber optic gyroscope.

[0004] Meanwhile, fiber optic loops are susceptible to external magnetic fields, causing changes in the phase of light waves and affecting the accuracy of fiber optic gyroscope detection. In existing technologies, to address the impact of external magnetic fields on the accuracy of fiber optic gyroscope detection, the following methods are typically used: one is to add a magnetic shielding cover to the outside of the fiber optic gyroscope. This method is simple and direct, but it increases the size and weight of the fiber optic gyroscope, which is not conducive to the requirements of lightweight and miniaturization. Another method is to add a magnetic shielding cover to the outside of a frameless fiber optic loop with a support frame. This method requires more internal space in the fiber optic gyroscope, which is also not conducive to the miniaturization requirements of the fiber optic gyroscope. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems in the prior art where additional stress is generated during the fixing process of the frameless fiber optic ring with the bracket, which affects the optical properties of the frameless fiber optic ring and reduces the accuracy of the optical gyroscope, and where adding a magnetic shielding cover to the fiber optic gyroscope is not conducive to the miniaturization of the fiber optic gyroscope. The invention provides a small frameless fiber optic ring assembly that can reduce stress and its preparation method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A small, frameless fiber optic ring assembly with stress reduction includes a frameless fiber optic ring; its distinctive feature is that it also includes a fiber optic ring support made of soft magnetic alloy material and an annular cover plate.

[0008] The fiber optic ring support is an integrally formed annular structure, including an annular bottom wall, and a first vertical wall and a second vertical wall connected to the bottom wall and extending upward, the three together forming an annular receiving chamber with an open top.

[0009] The first vertical wall has a fiber outlet hole, the outer wall of the second vertical wall has a circular mounting platform with a mounting hole, and the bottom wall has a groove for accommodating the fiber ring layer replacement part of the frameless fiber ring.

[0010] The cover plate is fixedly connected to the open end of the fiber optic ring bracket;

[0011] The frameless fiber optic ring is disposed within the receiving cavity and bonded to the bottom wall, while the remaining wall surfaces are all clearance-fitted with the inner wall surface of the fiber optic ring support.

[0012] Furthermore, recessed support steps are provided on the top end faces of both the first and second vertical walls, and the inner and outer rings of the cover plate overlap with the two support steps respectively, and the thickness of the cover plate is consistent with the height of the support steps.

[0013] Furthermore, the thickness of the second vertical wall is greater than the thickness of the first vertical wall.

[0014] Furthermore, the mounting platform has three mounting holes, and the fiber optic ring bracket is made of 1J79 soft magnetic alloy.

[0015] Furthermore, the groove depth is 0.2-0.3 mm.

[0016] Meanwhile, the present invention also provides a method for fabricating the above-mentioned stress-reducing small frameless fiber optic ring assembly, which is characterized by including the following steps:

[0017] Step 1: Obtain soft magnetic alloy raw materials and process them to obtain an integrally formed fiber optic ring support and a circular cover plate.

[0018] Step 2: Obtain a frameless fiber optic ring;

[0019] Step 3: Apply fiber ring adhesive evenly to the bottom wall of the fiber ring support obtained in Step 1, place the bottom surface of the frameless fiber ring obtained in Step 2 on the bottom wall with the fiber ring adhesive applied, and place the fiber ring layer on the bottom surface in the groove to obtain a preliminarily bonded fiber ring assembly.

[0020] Step 4: Place the initially bonded fiber optic ring assembly in an insulated box, gradually raise the temperature of the insulated box to the preset temperature, and keep it in the insulated box for a preset time for curing. After the insulated time is over, wait for the temperature of the insulated box to slowly cool down to room temperature before taking it out to obtain the cured fiber optic ring assembly.

[0021] Step 5: In the cured fiber optic ring assembly, the pigtail of the frameless fiber optic ring is led out of the receiving chamber through the fiber outlet hole, and a protective sleeve is fitted on the pigtail so that one end of the protective sleeve is fixed to the fiber optic ring bracket at the fiber outlet hole position with glue.

[0022] Step 6: After the protective sleeve is fixed with adhesive, install a cover plate on the open end of the fiber optic ring bracket and perform laser welding.

[0023] Step 7: After welding, apply silicone rubber to the connection between the fiber ring support and the protective sleeve to seal the fiber outlet hole, thus completing the fabrication of a small frameless fiber ring assembly that can reduce stress.

[0024] Furthermore, in step 3, the thickness of the adhesive coating on the fiber optic ring is 0.1-0.2 mm.

[0025] Furthermore, in step 4, the preset temperature is 78℃-82℃ and the preset time is 3.8h-4.2h.

[0026] Furthermore, in step 4, the preset temperature is 80℃ and the preset time is 4h.

[0027] Furthermore, in step 5, the protective sleeve is a polytetrafluoroethylene sleeve.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] 1. This invention discloses a small, frameless fiber optic ring assembly with reduced stress. It utilizes a one-piece molded fiber optic ring support made of soft magnetic alloy material, which is then laser-welded to a cover plate, ensuring a sealed cavity space. Furthermore, concentrating the welding points on the cover plate prevents deformation of the fiber optic ring support during welding, thus avoiding impact on the fiber optic performance. The fiber optic ring support, with its magnetic shielding function, not only supports the frameless fiber optic ring but also effectively reduces the influence of external magnetic fields and moisture on the internal frameless fiber optic ring. Its simple structure facilitates the miniaturization of fiber optic ring assemblies.

[0030] 2. Due to the mismatch in thermal expansion coefficients between the frameless fiber optic ring and the metal support after their fixed connection, the frameless fiber optic ring will generate additional stress under changes in external temperature, affecting its optical properties and reducing the accuracy of the fiber optic gyroscope. This invention provides a small frameless fiber optic ring assembly that reduces stress. By bonding one side of the frameless fiber optic ring to the bottom wall of the fiber optic ring support, with clearance fitting on other wall surfaces, it ensures a firm support while avoiding excessive contact between the frameless fiber optic ring and the support, thus improving the optical properties of the frameless fiber optic ring and consequently improving the accuracy of the fiber optic gyroscope.

[0031] 3. The present invention provides a small frameless fiber optic ring assembly that can reduce stress. By setting three mounting holes on the fiber optic ring assembly, it is stable and reliable, significantly improving the stability of the fiber optic ring assembly and enhancing the detection accuracy of the fiber optic gyroscope.

[0032] 4. The present invention provides a small frameless fiber optic ring assembly that can reduce stress. The thickness of the second vertical wall is designed to be greater than that of the first vertical wall, which can improve the installation strength of the fiber optic ring assembly while meeting the requirements of miniaturization.

[0033] 5. This invention provides a method for fabricating a miniature frameless fiber optic ring assembly that reduces stress. The fabricated fiber optic ring assembly exhibits significant miniaturization, effectively reducing the overall size and weight of the fiber optic gyroscope. Furthermore, the internal space of the fiber optic ring assembly is completely isolated from the external space, effectively preventing the influence of external moisture on the fiber optic ring and improving the stability of the frameless fiber optic ring. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of an embodiment of a small, frameless fiber optic ring assembly with stress reduction according to the present invention.

[0035] Figure 2 This is a top view of the fiber optic ring support in an embodiment of a small, frameless fiber optic ring assembly with stress reduction according to the present invention.

[0036] The annotations in the attached figures are explained as follows:

[0037] 1. Cover plate; 2. Fiber optic ring support; 21. First vertical wall; 22. Second vertical wall; 23. Bottom wall; 24. Mounting platform; 25. Fiber hole; 26. Groove; 3. Frameless fiber optic ring. Detailed Implementation

[0038] To make the objectives, advantages and features of the present invention clearer, the following describes in further detail, with reference to the accompanying drawings and specific embodiments, a small frameless fiber optic ring assembly with reduced stress and its preparation method.

[0039] like Figure 1-2 As shown, a small, frameless fiber optic ring assembly with reduced stress includes: a cover plate 1, a fiber optic ring support 2, and a frameless fiber optic ring 3. The fiber optic ring support 2 is a cylinder with an annular receiving chamber, the bottom wall 23 of which serves as the supporting part of the fiber optic ring support 2. The fiber optic ring support 2 is integrally formed using 1J79 soft magnetic alloy material. The cover plate 1 is an annular sheet structure whose dimensions match those of the fiber optic ring support 2, completely covering the opening of the fiber optic ring support 2. The frameless fiber optic ring 3 is a fiber optic ring wound according to the requirements of the target fiber optic gyroscope product itself.

[0040] Taking a frameless fiber optic ring 3 with an outer diameter of 26mm as an example, the outer diameter of the fiber optic ring support 2 is 28mm, and the wall thickness of its first vertical wall 21 and second vertical wall 22 is 0.5mm. The gap between the frameless fiber optic ring 3 and the inner wall of the fiber optic ring support 2, and between the frameless fiber optic ring 3 and the inner wall of the cover plate 1 after they are closed, is 0.5mm. The depth of the accommodating chamber of the fiber optic ring support 2 is 0.7mm higher than the height of the frameless fiber optic ring 3. A top view of the fiber optic ring support 2 is shown below. Figure 2 As shown, the support part of the fiber optic ring bracket 2 is the mounting platform 24, which is fixed with screws. Using three screws makes it more secure. The first vertical wall 21 has a fiber outlet hole 25, which is set as the fiber outlet hole of the frameless fiber optic ring 3. The purpose is to connect the frameless fiber optic ring 3 with the optical device of the fiber optic gyroscope. The bottom wall 23 has a groove 26 with a groove depth of 0.2-0.3mm to prevent the fiber optic ring layer replacement part from being squeezed.

[0041] The frameless fiber ring 3 is bonded to the inside of the fiber ring bracket 2 using a cured fiber ring adhesive. Both the fiber ring bracket 2 and the cover plate 1 are made of soft magnetic alloy material with high magnetic permeability (grade 1J79). The fiber ring bracket 2 and the cover plate 1 are tightly fitted together by laser welding, ensuring a closed cavity space, which can effectively reduce the influence of external magnetic fields and external water vapor environment on the internal fiber ring.

[0042] Meanwhile, the present invention also provides a method for preparing the above-mentioned stress-reducing small frameless fiber optic ring assembly as follows: to ensure the overall moisture-proof effect, the entire preparation process needs to be carried out in a workshop with dry conditions:

[0043] Step 1: Obtain soft magnetic alloy raw materials and process them to obtain an integrally formed fiber optic ring support 2 and a circular cover plate 1.

[0044] Step 2: Obtain the frameless fiber optic ring 3;

[0045] Step 3: Apply fiber optic ring adhesive evenly to the inner bottom wall 23 of the fiber optic ring support 2, with an adhesive layer thickness of 0.1-0.2 mm;

[0046] Step 4: Place the frameless fiber ring 3 into the annular receiving cavity of the fiber ring holder 2. Generally, the side of the frameless fiber ring closest to the pigtail is the top surface, and the opposite side is the bottom surface. The bottom surface is bonded to the bottom wall of the fiber ring holder 2. During placement, ensure that the fiber ring layer-changing protrusion of the frameless fiber ring 3 is positioned within the designated area. Figure 2 At the groove 26 indicated in the middle, and note that the remaining sidewalls of the frameless fiber ring 3 and the inner wall of the fiber ring bracket 2 should maintain a gap of 0.5mm to ensure that the frameless fiber ring 3 is completely placed at the bottom of the fiber ring bracket 2.

[0047] Step 5: Place the initially bonded fiber ring support 2 and frameless fiber ring 3 into an insulated box for high-temperature curing. The temperature of the insulated box is 80℃ and maintained for 4 hours. After curing, wait for the temperature of the insulated box to slowly cool down to room temperature before taking it out to accelerate the curing of the fiber ring adhesive and quickly reach a stable state.

[0048] Step 6: Place the pigtail of the frameless fiber ring 3 into... Figure 2 The fiber outlet hole 25 is marked, and a polytetrafluoroethylene sleeve is fitted on the pigtail to protect the pigtail at the fiber outlet hole 25. The sleeve and the fiber ring bracket 2 are temporarily fixed with glue, and the sleeve is fixed to the fiber outlet hole 25 of the fiber ring bracket 2.

[0049] Step 7: Slowly close the cover plate 1 and use laser welding to connect the two annular gaps where the cover plate 1 contacts the fiber ring bracket 2. Avoid the sleeve at the fiber outlet 25 to prevent the laser welding from damaging the sleeve and the pigtail.

[0050] Step 8: Apply silicone rubber to the connection between the fiber outlet 25 and the sleeve, completely fix the sleeve at the fiber outlet 25, and completely seal the fiber outlet.

[0051] Both the fiber optic ring support 2 and the cover plate 1 are made of 1J79 soft magnetic alloy material with high magnetic permeability, exhibiting excellent antimagnetic properties. This reduces the influence of external magnetic fields on the internal frameless fiber optic ring, effectively improving the antimagnetic performance of the fiber optic gyroscope. The overall size of this fiber optic ring assembly is only 2mm larger than the outer diameter of the internal frameless fiber optic ring, demonstrating significant miniaturization and effectively reducing the overall size and weight of the fiber optic gyroscope. The frameless fiber optic ring 3 is bonded to the fiber optic ring support 2 only through bottom bonding, effectively reducing stress compression problems caused by the inconsistency in thermal expansion coefficients between the frameless fiber optic ring 3 and the metal structural components, thus improving the performance of the frameless fiber optic ring 3 installed within it. This fiber optic ring assembly is fixed with three screws, ensuring stability and reliability, significantly improving the stability of the fiber optic ring assembly and enhancing the gyroscope's detection accuracy. The internal space of this fiber optic ring assembly is completely isolated from the external space, effectively preventing the influence of external moisture on the fiber optic ring and improving its stability.

[0052] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0053] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or mechanical connections. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0054] In the description of this invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A small, frameless fiber optic ring assembly with reduced stress, comprising a frameless fiber optic ring (3); characterized in that: It also includes a fiber optic ring support (2) made of soft magnetic alloy material and a circular cover plate (1); The fiber optic ring support (2) is an integrally formed ring structure, including a ring-shaped bottom wall (23), a first vertical wall (21) and a second vertical wall (22) connected to the bottom wall (23) and extending upward, which together form a ring-shaped receiving chamber with an open top. The first vertical wall (21) is provided with a fiber outlet hole (25), the outer wall surface of the second vertical wall (22) is provided with a circular mounting platform (24), the mounting platform (24) is provided with a mounting hole, and the bottom wall (23) is provided with a groove (26) for accommodating the fiber ring replacement part of the frameless fiber ring (3); The cover plate (1) is fixedly connected to the open end of the fiber optic ring bracket (2); The frameless fiber ring (3) is disposed in the receiving cavity and bonded to the bottom wall (23), and the remaining wall surfaces are all clearance-fitted with the inner wall surface of the fiber ring support (2).

2. The miniature frameless fiber optic ring assembly with reduced stress according to claim 1, characterized in that: The top surfaces of the first vertical wall (21) and the second vertical wall (22) are provided with recessed support steps. The inner and outer rings of the cover plate (1) overlap with the two support steps respectively, and the thickness of the cover plate (1) is consistent with the height of the support steps.

3. The stress-reducing miniature frameless fiber optic ring assembly according to claim 1, characterized in that: The thickness of the second vertical wall (22) is greater than the thickness of the first vertical wall (21).

4. The stress-reducing miniature frameless fiber optic ring assembly according to claim 1, characterized in that: The mounting platform has three mounting holes, and the fiber optic ring bracket (2) is made of 1J79 soft magnetic alloy.

5. The miniature frameless fiber optic ring assembly with reduced stress according to claim 1, characterized in that: The groove (26) has a groove depth of 0.2-0.3 mm.

6. A method for fabricating a small, frameless fiber optic ring assembly with reduced stress as described in claim 1, characterized in that, Includes the following steps: Step 1: Obtain soft magnetic alloy raw materials and process them to obtain an integrally formed fiber optic ring support (2) and a circular cover plate (1); Step 2: Obtain the frameless fiber optic ring (3); Step 3: Apply fiber ring adhesive evenly to the bottom wall (23) of the fiber ring support (2) obtained in step 1, place the bottom surface of the frameless fiber ring (3) obtained in step 2 on the bottom wall (23) on which the fiber ring adhesive has been applied, and place the fiber ring layer on the bottom surface in the groove (26) to obtain a preliminarily bonded fiber ring assembly. Step 4: Place the initially bonded fiber optic ring assembly in an insulated box, gradually raise the temperature of the insulated box to the preset temperature, and keep it in the insulated box for a preset time for curing. After the insulated time is over, wait for the temperature of the insulated box to slowly cool down to room temperature before taking it out to obtain the cured fiber optic ring assembly. Step 5: In the cured fiber optic ring assembly, the pigtail of the frameless fiber optic ring (3) is led out of the receiving chamber through the fiber outlet hole (25), and a protective sleeve is put on the pigtail so that one end of the protective sleeve is glued to the fiber optic ring bracket (2) at the fiber outlet hole (25). Step 6: After the protective sleeve is fixed with adhesive, install a cover plate (1) on the open end of the fiber optic ring bracket (2) and perform laser welding. Step 7: After welding, apply silicone rubber to the connection between the fiber ring support (2) and the protective sleeve to seal the fiber outlet hole (25), thus completing the preparation of a small frameless fiber ring assembly that can reduce stress.

7. The method for fabricating a small, frameless fiber optic ring assembly with reduced stress according to claim 6, characterized in that: In step 3, the thickness of the adhesive coating on the fiber optic ring is 0.1-0.2 mm.

8. The method for fabricating a small, frameless fiber optic ring assembly with reduced stress according to claim 6, characterized in that: In step 4, the preset temperature is 78℃-82℃ and the preset time is 3.8h-4.2h.

9. The method for fabricating a small, frameless fiber optic ring assembly with reduced stress according to claim 8, characterized in that: In step 4, the preset temperature is 80℃ and the preset time is 4h.

10. The method for fabricating a small, frameless fiber optic ring assembly with reduced stress according to claim 6, characterized in that: In step 5, the protective sleeve is a polytetrafluoroethylene sleeve.

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