A sealed light path structure of an ultra-high precision fiber-optic gyroscope

Abstract

The application discloses a sealed light path structure of an ultra-high-precision fiber-optic gyroscope, which comprises a body, a fiber ring assembly, a light source, a detector assembly, a sealing screw, a sealing cover, a sealing connector and an air outlet assembly. The fiber ring assembly is fixed to the body through the sealing screw, and the sealing screw and the sealing cover are respectively vacuum electron beam welded to the body to realize sealed connection of the fiber ring assembly; the light source and the detector assembly are located in the middle empty ring of the fiber assembly and are fixed to the body through screws, and the sealing connector is lead-tin welded to the body to realize sealed transmission of electrical characteristics of optical devices such as the light source and the detector assembly; the air outlet assembly structure is composed of an air outlet, a metal sealing plug and a nut, the air outlet part is vacuum electron beam sealed and welded to the body, and the metal sealing plug is tightly pressed on the air outlet by controlling the tightening torque of the nut to realize sealing of the air outlet assembly. Therefore, the performance of the micrometer fiber-optic gyroscope in a vacuum environment is improved.

Description

Technical Field

[0001] This application relates to the technical field of inertial sensors, and in particular to a sealed optical path structure for an ultra-high precision fiber optic gyroscope. Background Technology

[0002] The ultra-high precision fiber optic gyroscope micrometer is mainly used in Active Pointing Ultra-Quiet Platforms (VIPPS) for active pointing control. The product requires a measurement accuracy of 0.00008° / √h, making it the most accurate fiber optic gyroscope for space applications in China.

[0003] As precision increases, optical devices become more sensitive to vacuum environments, which in turn affects the performance of fiber optic gyroscopes in vacuum conditions. Summary of the Invention

[0004] The purpose of this invention is to address the performance degradation of existing high-precision micrometer fiber optic gyroscopes with unsealed optical paths in a vacuum environment, and to provide a fiber optic gyroscope optical path structure that is easy to assemble, highly reliable, and allows for the sealed assembly of optical components. The sealed optical path design of this invention effectively solves this problem while meeting the 15-year reliability requirement.

[0005] In the first aspect, a sealed optical path structure for an ultra-high precision fiber optic gyroscope is provided, including a body, a fiber optic ring assembly, optical and electrical components, a sealing cover, sealing screws, sealing connectors, and an air outlet assembly.

[0006] The sealing cover is sealed and fixedly connected to the body, and the cavity formed by the sealing cover and the body is used to accommodate the fiber optic ring assembly and optical and electrical devices.

[0007] The fiber optic ring assembly is fixedly connected to the body by a sealing screw, and the sealing screw is sealed to the body.

[0008] The optical and electrical devices are located within the space enclosed by the fiber optic ring of the fiber optic ring assembly;

[0009] The sealing connector is sealed and fixed to the body, and the sealing connector is used to seal and transmit the electrical characteristic signals of the optical and electrical devices to the outside.

[0010] The vent assembly is sealed and fixed to the body. Before the vent assembly is fully assembled, the vent assembly forms an vent channel to enable the sealed optical path structure to communicate with the outside gas. After the vent assembly is fully assembled, the vent assembly is used to isolate the sealed optical path structure from the outside gas.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the sealing cover and the body are welded by vacuum electron beam, the welding position gap between the sealing cover and the body is ≤0.1mm, and the weld meets the requirements of Class I weld in GJB1718A-2005.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the fiber optic ring assembly is fixed with screw holes;

[0013] The body has a first sink groove, and a first through hole is provided at the center of the first sink groove;

[0014] The sealing screw includes a head, a screw portion, and a countersunk portion, wherein the countersunk portion is located between the head and the screw portion in the extending direction of the screw portion;

[0015] The screw portion passes through the first through hole and is fixedly connected to the screw hole; the countersunk portion is welded and fixed to the first countersunk groove, and the welding area of ​​the countersunk portion and the first countersunk groove completely surrounds the axis of the screw portion.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the body has a second through hole, and the wall of the second through hole and the annular area surrounding the second through hole on the upper and lower end faces of the body are plated with a lead-tin alloy plating layer, and the sealing connector is welded to the second through hole by lead-tin sealing.

[0017] In conjunction with the first aspect, in some implementations of the first aspect, the lead-tin alloy plating thickness is 0.023 to 0.030 mm, and the clearance between the second through hole and the sealing connector is ≤0.3 mm.

[0018] In conjunction with the first aspect, in some implementations of the first aspect, the vent assembly 8 includes a vent, a metal sealing plug, and a nut;

[0019] The air outlet is sealed and fixed to the body. The air outlet includes a main body and a through air outlet channel. The air outlet channel includes a first channel portion. The inner diameter of the first channel portion matches and communicates with the inner diameter of the third through hole of the body.

[0020] The air outlet channel also includes a second channel portion, which is located on the side of the first channel portion away from the main body, and the inner wall of the second channel portion is conical.

[0021] The metal sealing plug is disposed in the second channel portion. The metal sealing plug includes a sealing plug body portion, which is a body with a gradually changing outer diameter and a circular cross-sectional shape.

[0022] The nut is of a circular groove structure, an inner wall of the circular groove of the nut is provided with threads for threaded fit with an outer wall of the main body of the air outlet nozzle, a groove opening of the circular groove of the nut is arranged opposite to the first channel portion, a groove bottom of the circular groove of the nut is arranged opposite to the second channel portion, and the groove bottom of the circular groove of the nut is configured to press the metal sealing plug against an inner wall of the second channel portion, so that an outer periphery of the main body of the sealing plug is in interference fit with the inner wall of the second channel portion.

[0023] With reference to the first aspect, in some implementations of the first aspect, an outer diameter of the main body of the sealing plug close to the body is larger than a minimum inner diameter of the second channel portion, an outer diameter of the main body of the sealing plug away from the body is smaller than a maximum inner diameter of the second channel portion, on an axis of the third through hole and along a direction from the optical fiber ring assembly to the body, an outer diameter change rate of the main body of the sealing plug decreases gradually, and the outer diameter change rate of the main body of the sealing plug satisfies a1<b<a2, where a1 is a minimum outer diameter change rate of the main body of the sealing plug, a2 is a maximum outer diameter change rate of the main body of the sealing plug, and b is an inner diameter change rate of the second channel portion.

[0024] With reference to the first aspect, in some implementations of the first aspect, the metal sealing plug further comprises a protruding portion, the protruding portion protrudes from the main body of the sealing plug in a direction away from the body; a fourth through hole is formed in the groove bottom of the circular groove of the nut, and the fourth through hole is configured for the protruding portion to pass through.

[0025] With reference to the first aspect, in some implementations of the first aspect, the body is provided with a second sinking groove, and the third through hole is arranged at a center of the second sinking groove; the air outlet nozzle further comprises a mounting platform, the mounting platform is arranged around the main body and located at an end of the main body close to the first channel portion, and the mounting platform is welded and fixed to the second sinking groove.

[0026] In a second aspect, an ultra-high precision fiber optic gyroscope is provided, the ultra-high precision fiber optic gyroscope comprises the sealed optical path structure according to any implementation of the first aspect described above.

[0027] Compared with the prior art, the solution provided by the present application at least has the following beneficial technical effects:

[0028] (1) The present invention realizes a structural design of an ultra-high precision fiber optic gyroscope sealed optical path, solves the defect of precision degradation of the ultra-high precision micrometer fiber optic gyroscope in a vacuum environment, and broadens the space application field of the ultra-high precision fiber optic gyroscope.

[0029] (2) The optical path structure design of the present invention ensures sealed welding while taking into account modular design. Each module is produced independently and in parallel, which improves the manufacturability and assemblability of the optical path structure.

[0030] (3) The air outlet assembly structure design of the present invention utilizes the different characteristics of metal hardness and achieves metal sealing design through interference fit, thereby improving the reliability of the fusion weld of the sealing optical path assembly. Attached Figure Description

[0031] Figure 1 An exploded view of the sealed optical path structure of an ultra-high precision fiber optic gyroscope.

[0032] Figure 2 This is a schematic diagram showing the location of the lead-tin plating on the body.

[0033] Figure 3 This is an exploded view and sectional view of the air outlet assembly. Detailed Implementation

[0034] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0035] like Figure 1 As shown, the present invention proposes a sealed optical path structure for an ultra-high precision fiber optic gyroscope, including a body 1, a fiber optic ring assembly 2, a light source 3, a detector assembly 4, a sealing cover 5, a sealing screw 6, a sealing connector 7, and an air outlet assembly 8.

[0036] like Figure 1 As shown, the sealing cover 5 and the body 1 are welded (e.g., vacuum electron beam welding) to achieve a sealed connection between the sealing cover 5 and the body 1. The cavity formed by the sealing cover 5 and the body 1 is used to accommodate the fiber optic ring assembly 2, the light source 3, and the detector assembly 4.

[0037] In some embodiments, the gap between the sealing cover 5 and the welding position of the body 1 is ≤0.1mm, and the weld meets the requirements of Class I weld in GJB1718A-2005.

[0038] like Figure 1 As shown, the fiber optic ring assembly 2 is secured to the body 1 by four sealing screws 6. The sealing screws 6 and the body 1 are welded together by vacuum electron beam welding to achieve a sealed assembly of the fiber optic ring assembly 2 and the body 1.

[0039] like Figure 1As shown, the sealing screw 6 may include a head, a screw portion, and a countersunk portion, wherein the countersunk portion is located between the head and the screw portion in the extending direction of the screw portion. A screw hole may be fixed on the fiber optic ring assembly 2. The body 1 may have a first recess, with a first through hole at its center. The screw portion of the sealing screw 6 may pass through the first through hole of the body 1 and be fixedly connected to the screw hole on the fiber optic ring assembly 2. The countersunk portion of the sealing screw 6 may be welded (e.g., vacuum electron beam sealing welding) to the first recess of the body 1, wherein the welded area of ​​the countersunk portion and the first recess completely surrounds the axis of the screw portion to prevent gas passage.

[0040] In some embodiments, the gap between the sealing screw 6 and the welding position of the body 1 is ≤0.1mm, and the weld meets the requirements of Class I weld in GJB1718A-2005.

[0041] like Figure 1 As shown, the light source 3, detector assembly 4, and other optical and electrical components can be located within the space enclosed by the optical fiber ring of the optical fiber ring assembly 2. The electrical characteristic signals of the light source 3, detector assembly 4, and other optical and electrical components are transmitted externally in a sealed manner through the sealed connector 7 on the main body 1.

[0042] like Figure 1 As shown, the sealing connector 7 itself has the characteristic of sealing electrical conduction. To avoid affecting electrical performance, the sealing connector 7 is soldered to the corresponding position on the body 1 using lead-tin. To ensure the sealing and reliability of the lead-tin soldering, a lead-tin alloy is plated at the second through hole through which the sealing connector 7 passes. Figure 2 As shown, in the second through hole, the upper and lower end faces of the body 1 are plated with a lead-tin alloy around the Φ30 area of ​​the second through hole. In one embodiment, the lead-tin alloy plating thickness is 0.023 to 0.030 mm, and the clearance between the second through hole on the body 1 and the sealing connector 7 is ≤0.3 mm.

[0043] like Figure 1 As shown, the vent assembly 8 is vacuum electron beam sealed and welded to the body 1. Before the vent assembly 8 is fully assembled (parts without or partially assembled vent assembly 8 are considered incomplete assemblies), the specified gas can enter the cavity formed by the sealing cover 5 and the body 1 through the hole on the body 1, allowing the cavity to contain the specified gas. Before actual use, the vent assembly 8 needs to be completely sealed and fixed to the body 1 to prevent gas leakage from the cavity formed by the sealing cover 5 and the body 1, or to prevent external gas from entering the cavity formed by the sealing cover 5 and the body 1.

[0044] Figure 3 A schematic structural diagram of an air outlet assembly 8 provided in an embodiment of this application is shown. The air outlet assembly 8 may include an air outlet 81, a metal sealing plug 82, and a nut 83.

[0045] The air outlet nozzle 81 may comprise a main body portion and a mounting platform. A through-going air outlet channel is provided in the main body portion. The mounting platform is arranged around the main body portion and located at one end of the main body portion. A second sinking groove may be provided on the body 1, and a third through hole is provided at the center of the second sinking groove. The mounting platform of the air outlet nozzle 81 may be welded and fixed to the second sinking groove of the body 1 (e.g., by vacuum electron beam seal welding). In one embodiment, the fit clearance at the welding position between the air outlet nozzle 81 and the body 1 is ≤ 0.1 mm, and the weld seam meets the requirements of Class I weld seams specified in GJB1718A-2005.

[0046] The air outlet channel of the main body portion may comprise a first channel section and a second channel section. The first channel section is located on a side of the second channel section closer to the body 1. An inner diameter of the first channel section may match an inner diameter of the third through hole on the body 1. An inner wall of the second channel section is tapered to accommodate the metal sealing plug 82.

[0047] The metal sealing plug 82 may comprise a sealing plug main body portion and a protruding portion. The sealing plug main body portion is a body with a gradually changing outer diameter and a circular cross-sectional shape. The protruding portion protrudes from the main body portion in a direction away from the body 1.

[0048] An outer diameter of the sealing plug main body portion at a position closer to the body 1 may be larger than a minimum inner diameter of the second channel section. An outer diameter of the sealing plug main body portion at a position away from the body 1 may be smaller than a maximum inner diameter of the second channel section. On an axis of the third through hole of the body 1 and along a direction from the fiber optic ring assembly 2 to the body 1, an outer diameter change rate of the sealing plug main body portion decreases from large to small, and satisfies a1 < b < a2, where a1 is the minimum outer diameter change rate of the sealing plug main body portion, a2 is the maximum outer diameter change rate of the sealing plug main body portion, and b is the inner diameter change rate of the tapered second channel section. Therefore, interference fit can be achieved when the main body portion of the metal sealing plug 82 is pressed against the inner wall of the second channel section of the main body portion of the air outlet nozzle 81.

[0049] The nut 83 may be of a circular grooved body structure, and a fourth through hole is provided on a groove end face of the circular grooved body. An outer periphery of the main body portion of the air outlet nozzle 81 may be provided with threads, an inner wall of the circular groove of the nut 83 may be provided with threads, and the outer periphery of the main body portion of the air outlet nozzle 81 and the inner wall of the circular groove of the nut 83 may be in threaded fit. The fourth through hole of the nut 83 is for the protruding portion of the metal sealing plug 82 to pass through, so as to axially position and calibrate the pressing of the metal sealing plug 82.

[0050] When assembling the vent assembly 8 on the main body 1, the vent 81 is first welded and fixed to the main body 1. Then, the metal sealing plug 82 is inserted into the second channel portion of the vent 81. Next, the nut 83 is installed. The protrusion of the metal sealing plug 82 is passed through the fourth through hole of the nut 83, and the nut 83 is tightened onto the outer periphery of the main body of the vent 81. As the nut 83 is tightened, the metal sealing plug 82 is gradually pressed against the inner wall of the vent 81, thereby forming an interference fit between the sealing plug body of the metal sealing plug 82 and the inner wall of the second channel portion of the vent 81 to achieve a seal.

[0051] In some embodiments, by controlling the tightening torque of the nut 83 to 10 N·m, the metal sealing plug 82 is pressurized to the corresponding conical hole position of the air outlet 81, thereby achieving the metal sealing function of the air outlet assembly 8.

[0052] In some embodiments, the external thread of the main body of the air outlet 81 is M12×1.25-6g, and the internal thread of the nut 83 is M12×1.25-6H, and the two are threaded together.

[0053] In some embodiments, the second channel portion of the air outlet 81 has a cone angle of 37°±0.5° and a surface roughness of Ra0.8; the sealing plug body of the metal sealing plug 82 is SR4 spherical and has a surface roughness of Ra0.8.

[0054] In some embodiments, the protrusion of the metal sealing plug 82 is a Φ4 cylinder, which serves as a stabilizing element when assembled with the fourth through hole of the nut 83.

[0055] In some embodiments, such as Figure 3 As shown, the main body of the vent 81 can protrude outward on the side opposite to the body 1 and engage with the groove on the inner wall of the nut 83 near the fourth channel. Since the outer diameter of the protruding part on the upper side of the main body is larger than the inner diameter of the opening of the nut 83, it can be used to limit the axial movement of the nut 83 to a certain extent.

[0056] In this invention, the air outlet assembly 8 utilizes the different hardness characteristics of metals to achieve a metal sealing design through interference fit, while avoiding the prohibition of sealing welding processes and improving the reliability of the weld.

[0057] This invention provides a structural design for a sealed optical path of an ultra-high precision fiber optic gyroscope, which solves the defect of precision degradation of ultra-high precision micrometer fiber optic gyroscopes in vacuum environment and broadens the spatial application field of ultra-high precision fiber optic gyroscopes.

[0058] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. A sealed optical path structure for an ultra-high precision fiber optic gyroscope, characterized in that, It includes the main body (1), fiber optic ring assembly (2), optical and electrical components, sealing cover (5), sealing screw (6), sealing connector (7), and vent assembly (8); The sealing cover (5) is sealed and fixedly connected to the body (1), and the cavity formed by the sealing cover (5) and the body (1) is used to accommodate the fiber optic ring assembly (2) and optical and electrical devices; The fiber optic ring assembly (2) is fixedly connected to the body (1) by a sealing screw (6), and the sealing screw (6) is sealed to the body (1). The optical and electrical devices are located in the space enclosed by the optical fiber ring of the optical fiber ring assembly (2); The sealing connector (7) is sealed and fixed to the body (1), and the sealing connector (7) is used to seal and transmit the electrical characteristic signals of the optical and electrical devices to the outside. The vent assembly (8) is sealed and fixed on the body (1). Before the vent assembly (8) is fully assembled, the vent assembly (8) forms an vent channel to enable the sealed optical path structure to communicate with the outside gas. After the vent assembly (8) is fully assembled, the vent assembly (8) is used to isolate the sealed optical path structure from the outside gas.

2. The sealed optical path structure according to claim 1, characterized in that, The sealing cover (5) and the body (1) are welded by vacuum electron beam. The welding position gap between the sealing cover (5) and the body (1) is ≤0.1mm, and the weld meets the requirements of Class I weld in GJB1718A-2005.

3. The sealed optical path structure according to claim 1, characterized in that, The fiber optic ring assembly (2) is fixed with screw holes; The body (1) has a first sinking groove, and a first through hole is provided at the center of the first sinking groove; The sealing screw (6) includes a head, a screw portion and a countersunk portion, wherein the countersunk portion is located between the head and the screw portion in the extending direction of the screw portion; The screw portion passes through the first through hole and is fixedly connected to the screw hole; the countersunk portion is welded and fixed to the first countersunk groove, and the welding area of ​​the countersunk portion and the first countersunk groove completely surrounds the axis of the screw portion.

4. The sealed optical path structure according to claim 1, characterized in that, The body (1) has a second through hole. On the wall of the second through hole, the annular area surrounding the second through hole on the upper and lower end faces of the body (1) is plated with a lead-tin alloy coating. The sealing connector (7) is welded to the second through hole by lead-tin sealing.

5. The sealed optical path structure according to claim 4, characterized in that, The lead-tin alloy plating thickness is 0.023-0.030 mm, and the gap between the second through hole and the sealing connector (7) is ≤0.3 mm.

6. The sealed optical path structure according to claim 1, characterized in that, The air outlet assembly (8) includes an air outlet (81), a metal sealing plug (82), and a nut (83); The air outlet (81) is sealed and fixed on the body (1). The air outlet (81) includes a main body and a through air outlet channel. The air outlet channel includes a first channel portion. The inner diameter of the first channel portion matches and communicates with the inner diameter of the third through hole of the body (1). The air outlet channel further comprises a second channel section, the second channel section is located on a side of the first channel section facing away from the body (1), and an inner wall of the second channel section is tapered; The metal sealing plug (82) is arranged in the second channel section, the metal sealing plug (82) comprises a sealing plug main body part, and the sealing plug main body part is a body with a gradually changing outer diameter and a circular cross-sectional shape; The nut (83) is of a circular groove structure, an inner wall of the circular groove of the nut (83) is provided with threads, which is configured to be in threaded fit with an outer wall of a main body portion of the air outlet nozzle (81), a notch of the circular groove of the nut (83) is arranged opposite to the first channel section, a groove bottom of the circular groove of the nut (83) is arranged opposite to the second channel section, and the groove bottom of the circular groove of the nut (83) is configured to press the metal sealing plug (82) against the inner wall of the second channel section, so that an outer periphery of the sealing plug main body part is in interference fit with the inner wall of the second channel section.

7. The sealed optical path structure according to claim 6, characterized in that, An outer diameter of the sealing plug main body part close to the body (1) is larger than a minimum inner diameter of the second channel section, an outer diameter of the sealing plug main body part far from the body (1) is smaller than a maximum inner diameter of the second channel section, on a hole axis of the third through hole, and along a direction from the optical fiber ring assembly (2) to the body (1), an outer diameter change rate of the sealing plug main body part decreases gradually, and the outer diameter change rate of the sealing plug main body part satisfies a1 < b < a2, wherein a1 is the minimum outer diameter change rate of the sealing plug main body part, a2 is the maximum outer diameter change rate of the sealing plug main body part, and b is the inner diameter change rate of the second channel section.

8. The sealed optical path structure according to claim 6, characterized in that, The metal sealing plug (82) further comprises a protruding part, and the protruding part protrudes from the sealing plug main body part in a direction facing away from the body (1); a groove bottom of the circular groove of the nut (83) is provided with a fourth through hole, and the fourth through hole is configured for the protruding part to pass through.

9. The sealed optical path structure according to claim 6, characterized in that, The body (1) is provided with a second countersunk groove, the third through hole is arranged at a center of the second countersunk groove; the air outlet nozzle (81) further comprises a mounting table, the mounting table is arranged around the main body part and located at an end of the main body part close to the first channel section, and the mounting table is welded and fixed to the second countersunk groove.

10. An ultra-high precision fiber optic gyroscope, characterized in that, The ultra-high precision fiber optic gyroscope comprises the sealed optical path structure according to any one of claims 1 to 9.

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