A hemispherical resonator and excitation cover welding device and welding method

Abstract

This invention relates to welding apparatus, specifically to a welding apparatus and method for welding a hemispherical resonator and an excitation cover. It addresses the problems of long heating times, easy oxidation of indium, poor welding reliability, inability to monitor indium flow depth in real time leading to unreliable resonator fixation, and inability to guarantee the assembly accuracy of the excitation cover and resonator in existing indium-sealed welding methods. This invention uses a welding base fixture to fix the excitation cover and hemispherical resonator. The laser generator can reciprocate vertically during welding via a sliding mechanism, and the rotating disk drives the welding base fixture to rotate, achieving uniform heating of indium during welding. Internal air is extracted through a degassing port, creating a low-vacuum environment inside the excitation cover to prevent indium oxidation from affecting flowability, thus achieving non-contact indium-sealed welding. Furthermore, the laser heating efficiency is high, the welding reliability is high, and an oven is not required, ensuring the assembly accuracy of the excitation cover and resonator.

Description

Technical Field

[0001] This invention relates to welding apparatus, and more specifically to a welding apparatus and method for welding a hemispherical resonator and an excitation cover. Background Technology

[0002] Due to their high precision, high reliability, long lifespan, small size, and radiation resistance, hemispherical resonator gyroscopes have gradually become a research hotspot in the field of inertial instruments. The fused silica resonator is the core component of the hemispherical resonator gyroscope. The resonator is welded to the excitation cover through a micro-gap, and indium-sealed welding, as a commonly used resonator welding technology, is widely applied in the welding of the resonator and the excitation cover.

[0003] The quality factor (Q value) of a resonator is one of the key indicators for evaluating its vibration characteristics. A higher Q value means the resonator can maintain vibration for a longer time, which can significantly reduce the interference introduced by applied vibration energy and improve the accuracy of the gyroscope. However, after the resonator is assembled and welded with the excitation cover and the detection base, the Q value of the resonator will be significantly reduced due to the influence of welding materials and assembly stress, resulting in a decrease in the performance of the hemispherical resonator gyroscope.

[0004] There are currently two main methods for welding harmonic oscillators:

[0005] Firstly, during the resonator welding process, a soldering iron is used to locally heat the end of the excitation cover, melting the indium inside the gap through heat conduction, thereby achieving resonator welding. However, since both the resonator and the excitation cover are made of fused silica glass, which has poor thermal conductivity, the indium inside the mating gap cannot be effectively welded by end heating when using indium-sealed welding. The heating time is too long, and indium is easily oxidized in air. The oxidized indium mixes in the gap, reducing the fluidity of indium inside the gap. The indium is unevenly filled in the gap, reducing the effective welding area. Insufficient indium filling leads to poor welding reliability. In addition, the resonator is not firmly fixed at the welding point, resulting in faster dissipation of the resonator's vibration energy. Therefore, the Q value of the resonator is significantly reduced after assembly.

[0006] Secondly, after the resonator and excitation cover are pre-assembled, they are placed in an oven for overall heating. This method can achieve indium sealing welding of the resonator. However, due to the poor thermal conductivity of glass material, the welding time is long. The indium flow depth cannot be monitored in real time in the oven, which can easily lead to insufficient welding depth or over-welding. Insufficient welding depth will result in unreliable fixation of the resonator, while over-welding will cause indium to fall from the gap, damaging the hemispherical resonator and causing welding failure. In addition, the oven will vibrate during the heating process, which cannot guarantee the assembly accuracy of the resonator and excitation cover. Summary of the Invention

[0007] The purpose of this invention is to solve the technical problems of long heating time, easy oxidation of indium, poor welding reliability, inability to monitor the indium flow depth in real time leading to unreliable fixation of the resonator, and inability to guarantee the assembly accuracy of the excitation cover and the resonator when welding the resonator to the excitation cover with indium seal. The invention provides a welding device and welding method for welding a hemispherical resonator to the excitation cover.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0009] A welding device for a hemispherical resonator and an excitation cover is provided for welding a hemispherical resonator and an excitation cover. The hemispherical resonator includes a handle and a hemispherical shell disposed on the handle. The excitation cover includes a hemispherical groove for accommodating the hemispherical shell with its opening facing downward, and a through hole vertically disposed at the top center of the hemispherical groove for engaging with the handle. After the handle is inserted into the through hole, there is a gap between it and the through hole, which is the welding gap. The device is characterized by including a fixing frame, a laser generator, an electric heating block, a welding base fixture, and a rotating disk.

[0010] The laser generator is connected to the fixed frame via a sliding mechanism, and the laser generator can move vertically via the sliding mechanism;

[0011] The rotating disk is positioned relative to the laser generator and mounted on a fixed frame. The welding base fixture is coaxially mounted on the rotating disk, and the rotating disk can drive the welding base fixture to rotate.

[0012] The upper end of the welding base fixture is coaxially provided with a stepped groove, including a first groove and a second groove. The first groove is located at the top of the second groove and the diameter of the first groove is larger than that of the second groove, so that the bottom of the first groove forms a stepped surface of the stepped groove. The stepped surface of the stepped groove is used to mate with the lower end face of the excitation cover, and the inner wall of the first groove is used to mate with the side wall of the excitation cover. The electric heating block is installed on the top surface of the excitation cover and is set corresponding to the through hole position of the excitation cover.

[0013] The welding base fixture has a degassing port radially opened on the side wall corresponding to the position of the second groove, which is used to connect to an external degassing device. An annular mounting groove is provided at the bottom center of the second groove. The annular mounting groove is used to fix the bottom end of the umbrella handle of the hemispherical harmonic oscillator, so that a welding gap is formed between the top end of the umbrella handle and the through hole.

[0014] Furthermore, the fixing frame includes a horizontal frame and a vertical frame vertically arranged on one side of the horizontal frame. The laser generator is connected to the vertical frame through a sliding mechanism, and the rotating disk is mounted on the horizontal frame.

[0015] Furthermore, the sliding mechanism includes a lifting rail arranged vertically on the frame, and the laser generator is slidably mounted on the lifting rail.

[0016] Furthermore, a degassing conduit is provided inside the degassing port, which is used to connect to an external degassing device.

[0017] Furthermore, the fixing frame and welding base fixture are made of stainless steel; the degassing conduit is made of copper alloy.

[0018] Meanwhile, the present invention also provides a method for welding a hemispherical resonator to an excitation cover, using the above-mentioned welding device for a hemispherical resonator to an excitation cover, characterized by comprising the following steps:

[0019] S1 cleaning welding base fixture ensures the surface is clean and free of dust or particles;

[0020] S2 After assembling the excitation cover and the hemispherical resonator, it is placed in the welding base fixture. The lower end face of the excitation cover abuts against the stepped surface of the stepped groove, and the side wall abuts against the inner wall of the first groove. The umbrella handle of the hemispherical resonator is located in the through hole of the excitation cover, and the bottom end of the umbrella handle is located in the annular mounting groove. The hemispherical shell of the hemispherical resonator is located in the hemispherical groove of the excitation cover, and there is a fitting gap between the two.

[0021] S3. Fill the welding gap with an indium sheet less than 0.05mm thick to form an indium-filled area. Observe the filling depth until the indium sheet is 3mm away from the hemispherical shell, and ensure that the circumferential filling is complete.

[0022] S4 starts the laser generator and adjusts the focus so that the laser spot falls on the indium-filled area, and starts the external degassing device;

[0023] S5 pre-fills some indium solder on the top surface of the excitation cover, installs the electric heating block on the top surface of the excitation cover and sets it in the corresponding through hole position, and then starts the electric heating block;

[0024] S6 adjusts the height of the laser generator via a sliding mechanism so that the laser spot is located at the lower end of the indium-filled part;

[0025] S7 starts the rotating disk. When the rotating disk drives the indium filling part to rotate, the laser spot generated by the laser generator moves up and down in the indium filling part through the sliding mechanism, so that the indium is heated evenly.

[0026] After every minute of welding, the indium solder pre-filled on the top surface of the excitation cover is removed and replaced with new indium solder;

[0027] S9 continues to observe. If indium is observed to flow to a distance of 2mm from the hemispherical shell, then proceed to step S10. If it is not observed, return to step S7.

[0028] S10 shuts down the laser generator, external degassing device, rotating disk, and electric heating block. After the electric heating block, excitation cover, and welding base fixture cool naturally to room temperature, the welding of the hemispherical resonator and excitation cover is completed.

[0029] Furthermore, in step S1, an organic solvent is used to clean the welding base fixture.

[0030] Furthermore, in step S5, the electric heating block is started by being powered by direct current, and the current is 3A.

[0031] Furthermore, in step S4, the power of the laser generator is 2-5W.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] (1) The present invention provides a welding device for a hemispherical resonator and an excitation cover. The excitation cover and the hemispherical resonator are installed and fixed by a welding base fixture. The laser generator can move vertically during welding through a sliding mechanism. The welding base fixture is rotated by a rotating disk. In the welding process, the indium can be uniformly heated. The internal air is extracted through the degassing port to create a low vacuum environment inside the excitation cover. This prevents the indium from oxidizing during welding and affecting its fluidity. It achieves non-contact indium sealing welding. The laser heating efficiency is high and the welding reliability is high. It does not require the use of an oven for heating, which ensures the assembly accuracy of the excitation cover and the resonator.

[0034] (2) In the welding method of the hemispherical resonator and the excitation cover of the present invention, indium solder is pre-filled on the top surface of the excitation cover. By continuously heating with an electric heating block, indium can be continuously added to the welding gap. Furthermore, the pre-filled indium solder can prevent the indium located in the welding gap from contacting the air and oxidizing.

[0035] (3) In the welding method of the hemispherical resonator and the excitation cover of the present invention, when filling the indium sheet, the indium sheet is stopped when it is 3mm away from the hemispherical shell. This can prevent the initial melting stage of indium from falling directly from the bottom of the welding gap to the hemispherical shell, thus affecting the accuracy. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of an embodiment of the welding device for a hemispherical resonator and an excitation cover according to the present invention in use;

[0037] Figure 2 This is a schematic diagram showing the assembly of the hemispherical resonator, excitation cover, welding fixture base, and electric heating block in an embodiment of the present invention.

[0038] The annotations in the attached figures are explained as follows:

[0039] 1-Fixed frame, 11-Horizontal frame, 12-Vertical frame; 2-Laser generator, 3-Electric heating block, 4-Welding base fixture, 41-First groove, 42-Second groove, 43-Annular mounting groove; 5-Rotating disc, 6-Degassing duct, 7-Excitation cover, 71-Hemispherical groove; 8-Hemispherical resonator, 81-Umbrella handle, 82-Hemispherical shell; 9-Lifting track. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0041] The structure of the hemispherical resonator 8 and excitation cover 7 used for welding in this invention is as follows: Figure 2 As shown, both are made of fused silica glass. The hemispherical resonator 8 includes a handle 81 and a hemispherical shell 82 disposed on the handle 81. The excitation cover 7 includes a hemispherical groove 71 for accommodating the hemispherical shell 82 with its opening facing downward, and a through hole vertically disposed at the top center of the hemispherical groove 71 for engaging with the handle 81. When the handle 81 is inserted into the through hole, there is a gap between it and the through hole. This gap is the welding gap.

[0042] Reference Figures 1-2 The present invention provides a welding device for a hemispherical resonator and an excitation cover, which includes a fixed frame 1. The fixed frame 1 is L-shaped and made of stainless steel to ensure structural strength. The fixed frame 1 includes a horizontal frame 11 and a vertical frame 12 vertically arranged on one side of the horizontal frame 11. A sliding mechanism is provided on the vertical frame 12. The laser generator 2 is connected to the vertical frame 12 through the sliding mechanism. In this embodiment, the sliding mechanism includes a lifting rail 9 arranged vertically on the vertical frame 12. The laser generator 2 is slidably mounted on the lifting rail 9 and can move vertically through the lifting rail 9.

[0043] A rotating disk 5 is positioned relative to the laser generator 2 and is mounted on a crossbeam 11. A welding base fixture 4 is coaxially mounted on the rotating disk 5. The rotating disk 5 can drive the welding base fixture 4 to rotate. The structure of the welding base fixture 4 is as follows: Figure 2 As shown, a stepped groove is coaxially provided at its upper end, including a first groove 41 and a second groove 42. The diameter of the first groove 41 is larger than the diameter of the second groove 42, and the first groove 41 is located at the top of the second groove 42, so that the bottom of the first groove 41 forms a stepped surface of the stepped groove. The stepped surface of the stepped groove is used to abut against the lower end face of the excitation cover 7, and the inner wall of the first groove 41 is used to abut against the side wall of the excitation cover 7. An annular mounting groove 43 is provided at the bottom of the second groove 42. When the bottom end of the umbrella handle 81 is inserted into the annular mounting groove 43, the annular mounting groove 43 can fix the position of the umbrella handle 81, so that a welding gap is formed between the umbrella handle 81 and the through hole.

[0044] After the excitation cover 7 is placed inside the welding base fixture 4, the electric heating block 3 is installed on the top surface of the excitation cover 7 and is positioned corresponding to the through hole of the excitation cover 7. The welding base fixture 4 is made of stainless steel to ensure structural strength.

[0045] To prevent indium oxidation during welding, a degassing port is radially provided on the side wall of the welding base fixture 4 at the position corresponding to the second groove 42. A degassing conduit 6 is provided inside the degassing port. It is made of copper alloy and is connected to an external degassing device. During welding, air can be extracted to form a low vacuum environment inside the excitation cover 7.

[0046] Meanwhile, the present invention also provides a method for welding a hemispherical resonator to an excitation cover, using the above-mentioned welding device for a hemispherical resonator to an excitation cover, including the following steps:

[0047] S1 uses organic solvents to clean the welding base fixture 4 to ensure the surface is clean and free of dust or particles;

[0048] After S2 assembles the excitation cover 7 and the hemispherical resonator 8, it is placed in the welding base fixture 4. The lower end face of the excitation cover 7 abuts against the stepped surface of the stepped groove, and the side wall abuts against the inner wall of the first groove 41. The top end of the umbrella handle 81 of the hemispherical resonator 8 is located in the through hole of the excitation cover 7, and the bottom end of the umbrella handle 81 is located in the annular mounting groove 43. The hemispherical shell 82 of the hemispherical resonator 8 is located in the hemispherical groove 71 of the excitation cover 7, and there is a fitting gap between the two.

[0049] S3. Fill the welding gap with an indium sheet less than 0.05 mm thick to form an indium-filled area. Observe the filling depth until the indium sheet is 82.3 mm away from the hemispherical shell, and ensure that the circumferential filling is complete.

[0050] S4 starts the laser generator 2 with a power of 2-5W, adjusts the focus so that the laser spot falls on the indium-filled part, and starts the external degassing device.

[0051] S5 prefills some indium solder on the top surface of the excitation cover 7, installs the electric heating block 3 on the top surface of the excitation cover 7 and sets it in the corresponding through hole position, then turns on DC power to start the electric heating block 3, and the current is 3A.

[0052] S6 adjusts the height of the laser generator 2 via a sliding mechanism so that the laser spot is located at the lower end of the indium-filled part;

[0053] S7 starts rotating disk 5. When rotating disk 5 drives the indium filling part to rotate, the laser spot generated by laser generator 2 moves up and down in the indium filling part through the sliding mechanism, so that the indium is heated evenly.

[0054] After each minute of welding, the indium solder pre-filled on the top surface of the excitation cover 7 is removed and replaced with new indium solder;

[0055] S9 continues to observe. If indium is observed to flow to a distance of 82.2 mm from the hemispherical shell, then proceed to step S10. If it is not observed, return to step S7.

[0056] S10 shuts down the laser generator 2, external degassing device, rotating disk 5, and electric heating block 3. After the electric heating block 3, excitation cover 7, and welding base fixture 4 have cooled naturally to room temperature, the welding of the hemispherical resonator 8 and excitation cover 7 is completed.

[0057] In step S5, indium solder is pre-filled on the top surface of the excitation cover 7 to prevent the indium in the welding gap from oxidizing due to contact with air. In step S8, new indium solder is applied every minute of welding to prevent oxidized indium from flowing into the welding gap. In step S4, the power of the laser generator 2 is 2-5W. If the power is too high, the indium will melt too quickly and damage the excitation cover 7 and the hemispherical resonator 8.

[0058] The embodiments described above are merely illustrative of specific implementations of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art 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 welding device for a hemispherical resonator and an excitation cover, used for welding a hemispherical resonator (8) and an excitation cover (7), wherein the hemispherical resonator (8) includes an umbrella handle (81) and a hemispherical shell (82) disposed on the umbrella handle (81), and the excitation cover (7) includes a hemispherical groove (71) for accommodating the hemispherical shell (82) with its opening facing downward, and a through hole vertically disposed at the top center of the hemispherical groove (71) for engaging with the umbrella handle (81), and a gap exists between the umbrella handle (81) and the through hole after the umbrella handle (81) is inserted into the through hole, the gap being a welding gap, characterized in that: It includes a fixed frame (1), a laser generator (2), an electric heating block (3), a welding base fixture (4), and a rotating disk (5); The laser generator (2) is connected to the fixed frame (1) through a sliding mechanism, and the laser generator (2) can move in the vertical direction through the sliding mechanism; The rotating disk (5) is positioned relative to the laser generator (2) and mounted on the fixed frame (1). The welding base fixture (4) is coaxially mounted on the rotating disk (5), and the rotating disk (5) can drive the welding base fixture (4) to rotate. The upper end of the welding base fixture (4) is coaxially provided with a stepped groove, including a first groove (41) and a second groove (42). The first groove (41) is located at the top of the second groove (42) and the diameter of the first groove (41) is larger than that of the second groove (42), so that the bottom of the first groove (41) forms a stepped surface of the stepped groove. The stepped surface of the stepped groove is used to cooperate with the lower end face of the excitation cover (7), and the inner wall of the first groove (41) is used to cooperate with the side wall of the excitation cover (7). The electric heating block (3) is installed on the top surface of the excitation cover (7) and is set corresponding to the through hole position of the excitation cover (7). The welding base fixture (4) has a degassing port radially opened on the side wall corresponding to the position of the second groove (42) for connecting to an external degassing device. The bottom of the second groove (42) is provided with an annular mounting groove (43), which is used to fix the bottom end of the umbrella handle (81) of the hemispherical resonator (8), so that a welding gap is formed between the top end of the umbrella handle (81) and the through hole.

2. The welding device for the hemispherical resonator and the excitation cover according to claim 1, characterized in that: The fixed frame (1) includes a horizontal frame (11) and a vertical frame (12) vertically arranged on one side of the horizontal frame (11). The laser generator (2) is connected to the vertical frame (12) through a sliding mechanism. The rotating disk (5) is mounted on the horizontal frame (11).

3. The welding device for the hemispherical resonator and the excitation cover according to claim 2, characterized in that: The sliding mechanism includes a lifting track (9) arranged vertically on the vertical frame (12), and the laser generator (2) is slidably mounted on the lifting track (9).

4. The hemispherical resonator and excitation cover welding device according to any one of claims 1-3, characterized in that: The degassing port is provided with a degassing conduit (6), which is used to connect to an external degassing device.

5. The welding device for the hemispherical resonator and the excitation cover according to claim 4, characterized in that: The fixing frame (1) and the welding base fixture (4) are made of stainless steel; the degassing conduit (6) is made of copper alloy.

6. A method for welding a hemispherical resonator to an excitation cover, employing the welding apparatus for a hemispherical resonator to an excitation cover as described in any one of claims 1-5, characterized in that, Includes the following steps: S1 Cleaning welding base fixture (4) to ensure the surface is clean and free of dust or particles; After S2 assembles the excitation cover (7) and the hemispherical resonator (8), it is placed in the welding base fixture (4). The lower end face of the excitation cover (7) abuts against the stepped surface of the stepped groove, and the side wall abuts against the inner wall of the first groove (41). The top end of the umbrella handle (81) of the hemispherical resonator (8) is located in the through hole of the excitation cover (7), and the bottom end of the umbrella handle (81) is located in the annular mounting groove (43). The hemispherical shell (82) of the hemispherical resonator (8) is located in the hemispherical groove (71) of the excitation cover (7), and there is a fitting gap between the two. S3 fills the welding gap with an indium sheet less than 0.05 mm thick to form an indium-filled part, observes the filling depth, and stops when the indium sheet is 3 mm away from the hemispherical shell (82), and ensures that the circumferential filling is complete; S4 starts the laser generator (2) and adjusts the focus so that the laser spot falls on the indium filling part, and starts the external degassing device; S5 prefills some indium solder on the top surface of the excitation cover (7), installs the electric heating block (3) on the top surface of the excitation cover (7) and sets it in the corresponding through hole position, and then starts the electric heating block (3); S6 adjusts the height of the laser generator (2) via a sliding mechanism so that the laser spot is located at the lower end of the indium-filled part; S7 starts rotating disk (5). When rotating disk (5) drives the indium filling part to rotate, the laser spot generated by laser generator (2) moves up and down in the indium filling part through sliding mechanism, so that the indium is heated evenly. S8 After welding for 1 minute, remove the indium solder pre-filled on the top surface of the excitation cover (7) and replace it with new indium solder; S9 continues to observe. If indium is observed to flow to a distance of 2 mm from the hemispherical shell (82), then step S10 is executed. If it is not observed, then return to step S7. S10 shuts down the laser generator (2), external degassing device, rotating disk (5) and electric heating block (3), and waits for the electric heating block (3), excitation cover (7) and welding base fixture (4) to cool naturally to room temperature, thus completing the welding of the hemispherical resonator (8) and excitation cover (7).

7. The welding method for the hemispherical resonator and the excitation cover according to claim 6, characterized in that: In step S1, the welding base fixture (4) is cleaned with an organic solvent.

8. The method for welding a hemispherical resonator to an excitation cover according to claim 7, characterized in that: In step S5, the electric heating block (3) is powered by DC current and the current is 3A.

9. The method for welding a hemispherical resonator to an excitation cover according to claim 8, characterized in that: In step S4, the power of the laser generator (2) is 2-5W.

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