Forming die for umbrella-shaped micro-hemispherical harmonic oscillator

Abstract

The forming die is provided with a forming surface and a forming cavity, the forming surface is used for placing a substrate for forming a spherical shell of the micro-hemispherical harmonic oscillator, the forming cavity comprises a first cavity and a second cavity, the first cavity is formed in the forming surface, the center of the bottom surface of the first cavity protrudes upwards to form a forming part, and the second cavity is formed in the forming surface. The forming part is matched with the inner wall face of a spherical shell of the micro-hemispherical resonator, the center of the top face of the forming part is sunken downwards to form a second cavity matched with a middle column of the micro-hemispherical resonator, the second cavity is used for containing the middle column, and the second cavity comprises a column cavity and a connecting cavity communicating with the column cavity and the first cavity. The cavity wall face of the connecting cavity extends outwards relative to the cavity wall face of the columnar cavity to form an arc face connected with the cavity wall of the first cavity, and when the middle column is arranged in the second cavity, the top face of the forming part is formed by the top face of the middle column. The integral structural strength of the formed micro-hemisphere can be improved, and the energy loss of the micro-hemisphere can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of hemispherical resonant gyroscope preparation, in particular to a forming die for an umbrella-shaped micro-hemispherical resonator. Background Art

[0002] The HRG is a new type of solid-state navigation gyroscope that measures precession angles. Its core component is a hemispherical resonator made of fused quartz. Due to its excellent mechanical and optical properties and the ability to achieve three-dimensional shell structure processing through mold forming, fused quartz is an excellent micromachining material with low thermal conductivity (KFS = 1.38W / (m·K)), low thermal expansion coefficient (αFS = 0.52×10 -6 / K), stable physical and chemical properties, and other excellent properties. It can be transformed into molten glass at high temperatures, with a softening temperature of approximately 1585°C. Therefore, it can be formed through rapid heating and cooling. Its excellent resistance to heat and cold shocks ensures that it will not break during the forming process, and the surface of the processed material has a good surface roughness.

[0003] Typically, hemispheres used in MEMS resonant gyroscopes are fabricated using a high-temperature blowtorch process, a relatively simple process that achieves high precision. Traditionally, this process involves thermoforming a fused quartz sheet using a graphite mold with a central pin. The process typically involves the following steps: 1) Upper and lower molds for the fused quartz micro-hemispherical shell structure are fabricated from graphite and mounted on a rotating platform, ensuring alignment between the molds and the center of the platform. 2) The quartz sheet is placed within the mold's pre-set retaining structure and the platform is activated for high-speed rotation. 3) A blowtorch is applied directly above the fused quartz sheet. A vacuum system is then activated to create negative pressure within the mold, creating a uniform downward suction force on the softened sheet. The softened fused quartz flows into the mold, forming a three-dimensional micro-shell structure. After processing, the micro-hemispherical structure has a W-shaped cross-section with a hollow anchor pin at the center. This is the classic micro-hemispherical structure, also known as a "birdbath" micro-hemispherical structure.

[0004] For the above thermoforming method, the following problems exist in the actual testing process of the micro-hemisphere:

[0005] 1) During the thermoforming and softening process of the quartz birdbath micro-hemisphere, due to its structural design, the lip area of ​​the hemisphere has the lowest degree of stretching, while the transition area between the anchor column and the lip has the highest degree of stretching. This results in a thick edge and a thin top. The top circumference area is extremely easy to break during testing and use.

[0006] 2) Reduce micro-hemispherical anchor losses: Traditional hollow anchor designs, based on the principle of energy loss, isolate waves from both sides of the shell before reaching the substrate, preventing them from canceling out and increasing anchor losses. Furthermore, shorter anchors make it easier for waves to escape from the shell into the substrate, increasing losses.

[0007] 3) Due to the inevitable temperature non-uniformity of the anchor structure of the quartz birdbath micro-hemisphere, when the sheet softens and contacts the mold (anchor position), even with a limited structure, the center point of the two may shift slightly due to the uneven deformation caused by the temperature difference after the sheet softens, thereby reducing the symmetry of the micro-hemisphere;

[0008] 4) The anchor column of the quartz bird basin micro-hemisphere is formed by stretching the top of the hemisphere from the inside to the lip. The special hollow deep cavity structure will cause subsequent process problems such as uneven coating and incomplete cleaning. Utility Model Content

[0009] In view of the problems in the background technology, the present invention proposes a molding die for an umbrella-shaped micro-hemispherical resonator, which can improve the overall structural strength of the molded micro-hemispherical resonator and reduce anchor loss.

[0010] The utility model adopts the following technical solutions:

[0011] A molding die for an umbrella-shaped micro-hemispherical resonator comprises a molding surface and a molding cavity. The molding surface is used to place a substrate for molding a spherical shell of the micro-hemispherical resonator. The molding cavity comprises a first cavity and a second cavity. The first cavity is opened on the molding surface. The center of the bottom surface of the first cavity bulges upward to form a molding portion. The molding portion cooperates with the inner wall surface of the spherical shell of the micro-hemispherical resonator. The center of the top surface of the molding portion is recessed downward to form a second cavity that cooperates with the middle column of the micro-hemispherical resonator and is used to accommodate the middle column. The second cavity comprises a column cavity and a connecting cavity connecting the column cavity and the first cavity. The cavity wall surface of the connecting cavity extends outward relative to the cavity wall surface of the column cavity to form an arc surface connected to the cavity wall of the first cavity. When the middle column is placed in the second cavity, its top surface forms the top surface of the molding portion.

[0012] Preferably, the curvature radius of the arc surface is 0.5-1 mm.

[0013] Preferably, the center of the bottom of the column cavity protrudes upward to form a conical positioning pin, and the positioning pin cooperates with the positioning groove in the center of the bottom surface of the middle column. When the middle column is placed in the second cavity, the positioning pin is clamped in the positioning groove.

[0014] Preferably, a limiting groove matching the outer circle of the bottom surface of the substrate is provided at the center of the molding surface of the molding die, and the first cavity is provided at the center of the bottom surface of the limiting groove.

[0015] Preferably, the molding mold is a graphite mold, and a negative pressure cavity for connecting to a vacuum device is opened at the center of the bottom surface of the molding mold. The edge of the negative pressure cavity extends upward to form an umbrella-shaped shell between the first cavity and the negative pressure cavity.

[0016] Preferably, the side wall surface of the negative pressure chamber is a conical surface that is narrow at the top and wide at the bottom.

[0017] Preferably, the center of the top surface of the forming mold extends upward to form a boss, and the top surface of the boss forms the forming surface.

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] Compared with the traditional mold for directly blowing a micro-hemispherical resonator with a high-temperature blowtorch, the molding mold of the umbrella-shaped micro-hemispherical resonator of the utility model cancels the design of the mold center pin. By designing a first cavity that matches the inner wall surface of the spherical shell of the umbrella-shaped micro-hemispherical resonator and a second cavity that accommodates a pre-prepared intermediate column, after the intermediate column is placed in the second cavity, the substrate on the first cavity is heated and the first cavity is in a negative pressure state. The substrate softens and adheres to the cavity wall of the first molding cavity under the action of negative pressure and contacts the intermediate column. After the softened substrate is solidified, the substrate forms the spherical shell of the umbrella-shaped micro-hemispherical resonator, and the spherical shell is fixedly connected to the intermediate column to form the umbrella-shaped micro-hemispherical resonator. Therefore, the utility model changes the traditional processing idea of ​​molding the spherical shell and the anchor column from a piece of fused quartz at the same time, avoids the phenomenon that the thickness of the micro-hemispherical shoulder is too thin due to the molding of the anchor column, and greatly improves the overall structural strength of the micro-hemispherical resonator. In addition, the utility model realizes the molding of an umbrella-shaped micro-hemispherical resonator through welding, and the prefabricated middle column can be designed as a solid anchor column, avoiding the problem of increased anchor loss caused by the limitation of the traditional one-piece molding mold structure that can only form hollow anchor columns, thereby reducing the energy loss of the micro-hemispherical resonator from the perspective of anchor loss.

[0020] Compared to the method of bonding the shell to the anchor column to form a micro-hemispherical resonator, the molding mold of the umbrella-shaped micro-hemispherical resonator of the utility model realizes the molding of the umbrella-shaped micro-hemispherical resonator by welding. Since the substrate is fixed to the intermediate column by welding, the two are made of the same amorphous material and the fixing process does not require dissimilar materials, so that interface-free melting can be achieved between the quartz parts, and the whole is integrated. Although the bonding method can achieve higher bonding strength, it will form an obvious discontinuous connection interface (bonding layer). After excitation, the shell vibrates at a high frequency, and the bonding interface will be subjected to a large shear force. If it is operated for a long time, there will be a risk of interface peeling and device damage. However, the quartz device after being melted by hydrogen-oxygen flame has the characteristics of the amorphous structure of the amorphous material, and the overall structure and material are continuous, and no stress concentration area will be generated. It can provide a higher overall structural strength than bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the present invention more easily understood, the present invention will be described in more detail with reference to the specific embodiments shown in the accompanying drawings. These drawings only depict typical embodiments of the present invention and should not be considered as limiting the scope of protection of the present invention.

[0022] Figure 1 This is a schematic diagram of the three-dimensional structure of the molding die of the umbrella-shaped micro-hemispherical resonator according to an embodiment of the present utility model.

[0023] Figure 2 This is a schematic diagram of the three-dimensional structure of the molding mold of the umbrella-shaped micro-hemispherical resonator according to an embodiment of the utility model from another perspective.

[0024] Figure 3 This is a schematic cross-sectional structure diagram of a molding die for an umbrella-shaped micro-hemispherical resonator according to an embodiment of the present utility model.

[0025] Figure 4 It is a schematic diagram of the cross-sectional structure of the middle column that cooperates with the second cavity.

[0026] Figure 5 This is a schematic diagram of the application state of the forming mold of the umbrella-shaped micro-hemispherical resonator according to an embodiment of the utility model.

[0027] Figure 6 This is a schematic diagram of the cross-sectional structure of a micro-hemispherical resonator formed by a forming mold of an umbrella-shaped micro-hemispherical resonator according to an embodiment of the utility model.

[0028] Reference numerals:

[0029] 1. Molding mold; 11. Molding surface; 12. First cavity; 13. Second cavity; 131. Column cavity; 132. Connecting cavity; 133. Arc surface; 14. Molding part; 15. Positioning pin; 16. Limiting groove; 17. Negative pressure cavity; 18. Boss; 2. Intermediate column; 21. Column; 22. Connecting part; 23. First arc surface; 24. Second arc surface; 25. Positioning groove; 3. Substrate; 4. Spherical shell. DETAILED DESCRIPTION

[0030] The following describes the implementation methods of the present invention with reference to the accompanying drawings so that those skilled in the art can better understand the present invention and implement it. However, the enumerated embodiments are not intended to limit the present invention. Unless there is a conflict, the following embodiments and the technical features in the embodiments can be combined with each other, and the same components are represented by the same figure marks.

[0031] like Figure 1-Figure 3As shown, the molding mold of the umbrella-shaped micro-hemispherical resonator of this embodiment, the molding mold 1 has a molding surface 11 and a molding cavity, the molding surface 11 is used to place the substrate 3 for molding the spherical shell of the micro-hemispherical resonator, the molding cavity includes a first cavity 12 and a second cavity 13, the first cavity 12 is opened on the molding surface, the bottom center of the first cavity 12 convexly forms a molding portion 14, the molding portion 14 cooperates with the inner wall surface of the spherical shell of the micro-hemispherical resonator, the top center of the molding portion 14 is recessed downwardly to form a second cavity 13 that cooperates with the middle column 2 of the micro-hemispherical resonator and is used to accommodate the middle column 2, the second cavity 13 includes a column cavity 131, and a connecting cavity 132 connecting the column cavity 131 and the first cavity 12, the cavity wall surface of the connecting cavity 132 extends outward relative to the cavity wall surface of the column cavity 131 to form an arc surface 133 connected to the cavity wall of the first cavity 12, and when the middle column 2 is placed in the second cavity 13, its top surface forms the top surface of the molding portion 14.

[0032] Compared with the traditional mold for directly blowing a micro-hemispherical resonator with a high-temperature blowtorch, the molding mold of the umbrella-shaped micro-hemispherical resonator of the utility model cancels the design of the mold center pin. By designing a first cavity 12 that matches the inner wall surface of the spherical shell of the umbrella-shaped micro-hemispherical resonator, and a second cavity 13 that accommodates the pre-prepared intermediate column 2, after the intermediate column 2 is placed in the second cavity 13, the substrate 3 on the first cavity 12 is heated and the first cavity 12 is in a negative pressure state. The substrate 3 softens and adheres to the cavity wall of the first molding cavity 12 and contacts the intermediate column 2 under the action of the negative pressure. After the softened substrate 3 is solidified, the substrate 3 forms the spherical shell 4 of the umbrella-shaped micro-hemispherical resonator. The spherical shell 4 is fixedly connected to the intermediate column 2 to form the umbrella-shaped micro-hemispherical resonator. Therefore, the utility model changes the traditional processing idea of ​​molding the spherical shell and the anchor column from a piece of fused quartz at the same time, avoids the phenomenon that the thickness of the micro-hemispherical shoulder is too thin due to the molding of the anchor column, and greatly improves the overall structural strength of the micro-hemispherical resonator. In addition, the utility model realizes the molding of an umbrella-shaped micro-hemispherical resonator through welding, and the prefabricated middle column can be designed as a solid anchor column, avoiding the problem of increased anchor loss caused by the limitation of the traditional one-piece molding mold structure that can only form hollow anchor columns, thereby reducing the energy loss of the micro-hemispherical resonator from the perspective of anchor loss.

[0033] Compared to the method of bonding the shell to the anchor column to form a micro-hemispherical resonator, the molding mold of the umbrella-shaped micro-hemispherical resonator of the utility model realizes the molding of the umbrella-shaped micro-hemispherical resonator by welding. Since the substrate is fixed to the intermediate column by welding, the two are made of the same amorphous material and the fixing process does not require dissimilar materials, so that interface-free melting can be achieved between the quartz parts, and the whole is integrated. Although the bonding method can achieve higher bonding strength, it will form an obvious discontinuous connection interface (bonding layer). After excitation, the shell vibrates at a high frequency, and the bonding interface will be subjected to a large shear force. If it is operated for a long time, there will be a risk of interface peeling and device damage. However, the quartz device after being melted by hydrogen-oxygen flame has the characteristics of the amorphous structure of the amorphous material, and the overall structure and material are continuous, and no stress concentration area will be generated. It can provide a higher overall structural strength than bonding.

[0034] In this embodiment, the curvature radius of the arc surface is 0.5-1 mm.

[0035] Among them, such as Figure 4 As shown, correspondingly, the intermediate column 2 that cooperates with the second cavity 13 includes a column 21, the top surface of the column 21 has a connecting portion 22 that is integrally formed with the column 21 and coaxially arranged, and the side surface of the connecting portion 22 extends outward relative to the side surface of the column 21 to form a first arc surface 23, and the first arc surface 23 cooperates with the circular arc surface 133. The top surface of the connecting portion 22 bulges upward to form a second arc surface 24. That is, after the intermediate column 2 is located in the second cavity 13, the top surface of the connecting portion 22 - the second arc surface 24 forms the top of the molding portion 14, closing the top of the molding portion 14, so that the wall surface of the molding portion 14 forms a hemispherical surface that cooperates with the inner spherical surface of the umbrella-shaped micro-hemisphere resonator.

[0036] In this embodiment, the center of the bottom of the column cavity 131 protrudes upward to form a conical positioning pin 15, and the positioning pin 15 cooperates with the positioning groove 25 at the center of the bottom surface of the middle column 2. When the middle column 2 is placed in the second cavity 13, the positioning pin 15 is stuck in the positioning groove 25.

[0037] After the middle column 2 is assembled in the second cavity 13, the positioning pin 15 fits in the positioning groove 25, anchoring the middle column 2 in the center of the second cavity 13, while preventing the anchor column from shaking slightly or fitting against the edge of the mold during the molding process, causing structural errors.

[0038] In this embodiment, a limiting groove 16 matching the outer circle of the bottom surface of the substrate 3 is provided at the center of the molding surface 11 of the molding die 1 , and the first cavity 12 is provided at the center of the bottom surface of the limiting groove 16 .

[0039] The substrate 3 is limited by the limiting groove 16 to ensure that the central axis of the substrate 3 and the geometric center of the second cavity 13 are completely coincident during the forming process.

[0040] In this embodiment, the molding mold 1 is a graphite mold, and a negative pressure cavity 17 for connecting to a vacuum pump is opened at the center of the bottom surface of the molding mold 1. The edge of the negative pressure cavity 17 extends upward to form an umbrella-shaped shell between the first cavity 12 and the negative pressure cavity 17.

[0041] The negative pressure cavity 17 of the molding mold is connected to the molding cavity through countless tiny pores on the shell that are invisible to the naked eye. When molding, the negative pressure cavity 17 generates negative pressure by connecting to the negative pressure equipment, and acts on the molding cavity through the pores, causing the softened molten substrate to extend downward and take shape.

[0042] In this embodiment, the sidewalls of negative pressure chamber 17 are tapered, narrow at the top and wide at the bottom, to minimize energy loss in the vortex zone and improve negative pressure extraction efficiency. To minimize adsorption of gas molecules and localized negative pressure unevenness, the inner corners of negative pressure chamber 17 are rounded (R0.25-R0.5) to ensure a smooth interior.

[0043] In this embodiment, the center of the top surface of the forming mold extends upward to form a boss 18 , and the top surface of the boss 18 forms the forming surface 11 .

[0044] The following is a process flow of an example of a specific application of the present invention to form an umbrella-shaped micro-hemispherical resonator (see Figure 5 ):

[0045] 1) After confirming that there are no structural defects or other problems using an optical microscope, ultrasonically clean the substrate 3 and the intermediate pillar 2 using an organic solvent such as acetone and an acid solution (hydrochloric acid, sulfuric acid, etc.);

[0046] 2) The intermediate pillar 2 is placed in the second cavity of the forming mold 1. After the intermediate pillar 2 and the central axis of the forming mold 1 are self-aligned by the cooperation of the positioning groove 25 and the positioning pin 15, the intermediate pillar 2 and the forming mold 1 are preheated to a temperature of approximately 1000°C using an oxyhydrogen flame to prevent the formation of local thermal stress caused by a large temperature difference between the intermediate pillar 2 and the substrate 3 during the forming process;

[0047] 3) Place the substrate 3 in the limiting groove 16 of the forming mold 1, start the turntable so that the forming mold 1 drives the substrate 3 to rotate at a certain speed; after setting the ratio of hydrogen and oxygen (temperature control), turn on the hydrogen-oxygen flame to heat the substrate 3;

[0048] 4) After the temperature reaches the melting point of the quartz glass, as observed by an infrared thermometer, the vacuum system is turned on to generate negative pressure in the negative pressure chamber 17. The negative pressure suction is then transmitted to the molding cavity of the molding mold through the capillaries in the mold wall. The softened substrate 3 is extended downward under the action of the negative pressure to form the mold.

[0049] 5) The substrate 3 is formed onto the surface of the forming portion of the forming mold to form an umbrella-shaped spherical shell structure; at the same time, the center bottom of the substrate 3 contacts the top surface of the middle column 2 to complete the welding.

[0050] Figure 6 This is a schematic diagram of the structure of the umbrella-shaped micro-hemispherical resonator after forming. Compared to traditional quartz birdbath designs, the hemispherical cup-shaped shell has a more uniform thickness distribution due to the lack of significant stretching, which contributes to a more consistent Q value. Furthermore, the transition area between the shell 4 and the intermediate column 2 of the formed umbrella-shaped micro-hemispherical resonator is a smooth contour.

[0051] The embodiments described above are merely preferred embodiments of the present invention. The phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments" used in this specification may refer to one or more of the same or different embodiments of the present disclosure. Any common changes and substitutions made by those skilled in the art within the scope of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A molding die for an umbrella-shaped micro-hemispherical resonator, characterized in that: The molding die (1) has a molding surface (11) and a molding cavity. The molding surface (11) is used to place a substrate (3) for molding a micro-hemispherical resonator shell. The molding cavity includes a first cavity (12) and a second cavity (13). The first cavity (12) is opened on the molding surface. The center of the bottom surface of the first cavity (12) bulges upward to form a molding portion (14). The molding portion (14) cooperates with the inner wall surface of the spherical shell of the micro-hemispherical resonator. The center of the top surface of the molding portion (14) is concave downward to form a center of the micro-hemispherical resonator. The second cavity (13) matched with the column (2) is used to accommodate the intermediate column (2). The second cavity (13) includes a column cavity (131) and a connecting cavity (132) connecting the column cavity (131) and the first cavity (12). The cavity wall surface of the connecting cavity (132) extends outward relative to the cavity wall surface of the column cavity (131) to form an arc surface (133) connected to the cavity wall of the first cavity (12). When the intermediate column (2) is placed in the second cavity (13), its top surface forms the top surface of the forming portion (14).

2. The molding die for the umbrella-shaped micro-hemispherical resonator according to claim 1, characterized in that: The curvature radius of the arc surface (133) is 0.5-1 mm.

3. The molding die for the umbrella-shaped micro-hemispherical resonator according to claim 1, characterized in that: The center of the bottom of the column cavity (131) protrudes upward to form a conical positioning pin (15), and the positioning pin (15) cooperates with the positioning groove at the center of the bottom surface of the middle column. When the middle column (2) is placed in the second cavity (13), the positioning pin (15) is clamped in the positioning groove.

4. The molding die for the umbrella-shaped micro-hemispherical resonator according to claim 1, characterized in that: A limiting groove (16) matching the outer circle of the bottom surface of the substrate (3) is provided at the center of the forming surface (11) of the forming mold (1), and the first cavity (12) is provided at the center of the bottom surface of the limiting groove (16).

5. The molding die for the umbrella-shaped micro-hemispherical resonator according to any one of claims 1 to 4, characterized in that: The forming mold (1) is a graphite mold, and a negative pressure cavity (17) for communicating with a vacuum pump is provided at the center of the bottom surface of the forming mold (1), and the edge of the negative pressure cavity (17) extends upward to form an umbrella-shaped shell between the first cavity (12) and the negative pressure cavity (17).

6. The molding die for the umbrella-shaped micro-hemispherical resonator according to claim 5, characterized in that: The side wall surface of the negative pressure chamber (17) is a conical surface that is narrow at the top and wide at the bottom.

7. The molding die for an umbrella-shaped micro-hemispherical resonator according to any one of claims 1 to 4, characterized in that: The center of the top surface of the molding die extends upward to form a boss (18), and the top surface of the boss (18) forms the molding surface (11).

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