Oil-filled pressure core and preparation method thereof

Abstract

The invention provides an oil-filled pressure core which comprises a tube seat, a corrugated diaphragm, a ceramic seat and a silicon pressure chip, the corrugated diaphragm, the ceramic seat and the silicon pressure chip are all arranged on the tube seat, an oil storage inner cavity is formed between the corrugated diaphragm and the ceramic seat, an oil filling hole for injecting silicone oil into the oil storage inner cavity is formed in the tube seat, and the silicon pressure chip is arranged in the oil filling hole. The ceramic seat is provided with an oil guide hole for injecting silicone oil into the oil storage inner cavity, the oil filling hole is communicated with the oil storage inner cavity through the oil guide hole, the ceramic seat is further provided with a pressure guide hole for enabling the silicone oil in the oil storage inner cavity to flow to the silicon pressure chip, and the silicon pressure chip is electrically connected with a pin on the tube seat. The corrugated diaphragm comprises a first dome-shaped surface, the ceramic seat is provided with a second dome-shaped surface with the same radian as the first dome-shaped surface, and the oil storage inner cavity is located between the first dome-shaped surface and the second dome-shaped surface. The invention further provides a preparation method of the oil-filled pressure core.

Description

Technical Field

[0001] This invention relates to the field of pressure sensor technology, and in particular to an oil-filled pressure core and its preparation method. Background Technology

[0002] Oil-filled pressure cores are made by encapsulating a silicon piezoresistive pressure sensing element within a stainless steel housing. Their working principle involves using an insulating diaphragm and internally filled silicone oil to transmit external pressure seamlessly to the internal sensing chip. The chip senses the pressure and converts the pressure signal into an electrical signal for output. They are widely used in on-site measurement and control of industrial processes such as water supply / drainage, heating, petroleum, chemical, and metallurgy.

[0003] Oil-filled pressure cores commonly use planar corrugated diaphragms as the isolation diaphragm. The main body of the core has a circular planar structure with concentric annular corrugated structures in the center to enhance deformation capacity and sensitivity. Currently, oil-filled pressure cores using planar diaphragms have the following problems:

[0004] First, due to the inherent structural characteristics of planar diaphragms, stress tends to concentrate at the corrugations and center point when subjected to overload pressure, impact, and vibration, leading to permanent deformation or rupture. Second, while planar diaphragms exhibit good linearity with minor deformations, the nonlinearity of the pressure core increases significantly with larger pressure measurements due to the compressibility of silicone oil and increased diaphragm displacement. Third, stress concentration at the corrugations and center point causes the gradual accumulation of microscopic plastic deformation within the material (the primary cause of hysteresis and drift), reducing the output stability and long-term reliability of the pressure core. Furthermore, when measuring rapidly changing pressures, planar diaphragm pressure cores exhibit measurement distortion due to diaphragm vibration, resulting in poor dynamic response characteristics.

[0005] Therefore, it is necessary to design a new oil-filled pressure core to overcome the above problems. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art and provide an oil-filled pressure core and its preparation method. This invention solves at least some of the problems in the prior art.

[0007] This invention is implemented as follows:

[0008] This invention provides an oil-filled pressure core, comprising a tube base, a corrugated diaphragm, a ceramic seat, and a silicon pressure chip. The corrugated diaphragm, ceramic seat, and silicon pressure chip are all mounted on the tube base, and an oil storage cavity is formed between the corrugated diaphragm and the ceramic seat. The corrugated diaphragm includes a first domed surface, and the ceramic seat has a second domed surface with the same curvature as the first domed surface. The oil storage cavity is located between the first domed surface and the second domed surface. The ceramic seat also has a pressure-guiding hole for allowing the silicon oil in the oil storage cavity to flow to the silicon pressure chip.

[0009] Furthermore, the ceramic seat includes a first ceramic body and a second ceramic body. The oil inlet is disposed on the first ceramic body and includes a large-diameter section and a small-diameter section. The second ceramic body is located within the large-diameter section, and the silicon pressure chip is located within the small-diameter section. The silicon pressure chip is located below the second ceramic body, and the pressure inlet is located on the second ceramic body. The first ceramic body has a first arcuate surface with the same curvature as the first dome surface, and the second ceramic body has a second arcuate surface with the same curvature as the first dome surface. The first arcuate surface and the second arcuate surface are spliced ​​together to form a complete second dome surface.

[0010] Furthermore, the first ceramic body is also provided with a pin hole, and the pins on the tube socket extend into the pin hole. The pins are electrically connected to the silicon pressure chip through leads. The stepped surface of the stepped hole is provided with a lead groove for receiving leads.

[0011] Furthermore, the first dome-shaped surface is provided with a plurality of first corrugations, each of which is arranged around the central axis of the corrugated diaphragm. The first arc-shaped surface is provided with a plurality of second corrugations, each of which is arranged around the central axis of the first ceramic body. The positions of the second corrugations correspond to those of the first corrugations, and the waveforms and sizes of the corrugations are matched.

[0012] Furthermore, the cross-sectional shape of the first corrugation is an arc shape, a sine shape, a triangle, or a trapezoid.

[0013] Furthermore, the second ceramic body is fixed in the large-diameter section with sealant, and the first ceramic body and the silicon pressure chip are both fixed on the tube base with sealant.

[0014] Furthermore, the corrugated diaphragm also includes an annular plane, which is arranged around the first domed surface. The annular plane is located between the end face of the welding ring and the positive pressure side of the tube seat, and the annular plane is welded and fixed to the tube seat by the welding ring.

[0015] Furthermore, the first domed surface is a spherical cap, an ellipsoidal cap, or a paraboloid of revolution.

[0016] This invention also provides a method for preparing an oil-filled pressure core, characterized by comprising the following steps:

[0017] S1. The first ceramic body and the silicon pressure chip are respectively bonded to the tube socket, and the adhesive is cured.

[0018] S2. Perform plasma cleaning on the socket after bonding the silicon pressure chip;

[0019] S3. Wire bonding technology is used to achieve electrical connection between the silicon pressure chip and the pins on the socket;

[0020] S4. Adhere the second ceramic body to the first ceramic body and cure the adhesive;

[0021] S5. Install the corrugated diaphragm and welding ring onto the metal base of the pipe seat, and weld the three together; the corrugated diaphragm forms an oil storage cavity with the first ceramic body and the second ceramic body;

[0022] S6. Place the welded tube seat in a vacuum oven for high-temperature baking to remove moisture and organic residues from the oil storage cavity;

[0023] S7. Inject silicone oil into the oil reservoir cavity through the oil filling hole on the pipe seat;

[0024] S8. Seal the oil filling hole of the base.

[0025] Furthermore, the corrugated diaphragm is manufactured by stamping or high-pressure fluid forming.

[0026] The present invention has the following beneficial effects:

[0027] 1. In this invention, the dome-shaped surface of the corrugated diaphragm is a natural pressure-resistant structure that can uniformly convert the pressure applied to the diaphragm surface into thin-film stress (rather than bending stress) within the diaphragm, thereby minimizing stress concentration. This allows the sensor to withstand pressure overloads and pressure shocks several times its range, and even recover after instantaneous extremely high pressure peaks without deformation or permanent failure. This invention solves the problem that when an oil-filled pressure core is subjected to certain overload pressure, impact, and vibration, stress tends to concentrate at the corrugations and center point, leading to permanent deformation or breakage.

[0028] 2. Compared to planar structures, dome structures have higher rigidity, which gives the oil-filled pressure core better dynamic response characteristics, enabling more accurate measurement of rapidly changing pressure without distortion due to diaphragm vibration. Compared to planar structures, dome structures have a larger surface area, meaning that within a certain working radius (the cross-sectional radius of the pressure-sensing side), the corrugated diaphragm and silicone oil have a larger contact area, thereby improving the sensitivity of the diaphragm in transmitting pressure.

[0029] 3. The corrugated structure on the dome surface of the corrugated diaphragm can reduce the self-deformation stress of the diaphragm and make the stress evenly distributed, thereby improving the linearity and sensitivity of the pressure core.

[0030] 4. The domed surface and corrugations on the corrugated diaphragm match the size and shape of the domed surface and corrugations on the ceramic base, and their normal distances are similar. On the one hand, this can minimize the amount of oil inside the oil-filled pressure core, improving the nonlinearity and temperature drift characteristics of the oil-filled pressure core. On the other hand, when the oil-filled pressure core is subjected to extreme impacts, vibrations, and alternating pressures from all directions in space, even if the corrugated diaphragm touches the ceramic base, it will not adversely affect the shape of the corrugated diaphragm or the measurement accuracy of the oil-filled pressure core, greatly improving the impact and vibration resistance of the oil-filled pressure core and its dynamic measurement accuracy. In this invention, the combined ceramic body structure with domed surfaces improves the temperature drift and measurement accuracy of the pressure core, and enhances its impact and vibration resistance. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is an exploded view of the oil-filled pressure core provided in Embodiment 1 of the present invention;

[0033] Figure 2 This is an assembly diagram of the oil-filled pressure core provided in Embodiment 1 of the present invention;

[0034] Figure 3 This is a schematic diagram of the tube seat provided in Embodiment 1 of the present invention;

[0035] Figure 4 This is a schematic diagram of the corrugated diaphragm provided in Embodiment 1 of the present invention;

[0036] Figure 5 This is a schematic diagram of the structure of the first ceramic body provided in Embodiment 1 of the present invention;

[0037] Figure 6 This is a schematic diagram of the structure of the second ceramic body provided in Embodiment 1 of the present invention;

[0038] Figure 7 This is a schematic diagram of the lead connection structure provided in Embodiment 1 of the present invention;

[0039] Figure 8This is an assembly diagram of the first ceramic body, the second ceramic body, and the corrugated diaphragm provided in Embodiment 1 of the present invention;

[0040] Figure 9 This is a flowchart of the corrugated diaphragm stamping process provided in Embodiment 1 of the present invention;

[0041] Figure 10 This is an assembly diagram of the oil-filled pressure core provided in Embodiment 2 of the present invention;

[0042] Figure 11 This is a schematic diagram of the corrugated diaphragm provided in Embodiment 2 of the present invention;

[0043] Figure 12 This is a schematic diagram of the assembly of the first ceramic body and the second ceramic body provided in Embodiment 2 of the present invention.

[0044] Figure 1 , Figure 2 In the middle: 1. tube socket, 2. O-ring, 3. sealant, 4. lead wire, 5. corrugated diaphragm, 6. solder ring, 7. first ceramic body, 8. second ceramic body, 9. silicon pressure chip, 10. silicone oil and 11. pin.

[0045] Figure 3 In the middle: the tube socket 1 includes a base 1.1, a sealing glass 1.2, and a lead 1.3. The base 1.1 includes an annular groove 1.1-1, an annular end face 1.1-2, an inner bottom surface of the annular groove 1.1-3, an oil filling hole 1.1-4, a groove 1.1-5, and a vent hole 1.1-6.

[0046] Figure 4 middle, Figure 9 In the middle: the corrugated diaphragm 5 includes an annular plane 5.1, a first domed surface 5.2, and a first corrugation 5.3.

[0047] Figure 5 , Figure 8 In the middle: the first ceramic body 7 includes a stepped hole 7.1, a side wall 7.2, an oil inlet hole 7.3, a first bottom surface 7.4, a lead hole 7.5, a lead wire groove 7.6, a stepped surface 7.7, a second corrugation 7.8, and a first arc-shaped surface 7.9.

[0048] Figure 6 , Figure 8 In the middle: the second ceramic body 8 includes a second bottom surface 8.1, a side surface 8.2, a second arc-shaped surface 8.3, and a pressure hole 8.4.

[0049] Figure 7 , Figure 8 In the middle: pins 1.3, lead wire 4, silicon pressure chip 9.

[0050] Figure 9 In the middle: flat film blank 12, first stamping 13, second stamping 14.

[0051] Figure 10 Example 2: Corrugated diaphragm 5, first ceramic body 7, second ceramic body 8.

[0052] Figure 11 (Example 2): The corrugated diaphragm 5 includes an annular plane 5.1, a first domed surface 5.2, and corrugations 5.3.

[0053] Figure 12 Example 2: First ceramic body 7, oil inlet hole 7.3, second ceramic body 8, pressure inlet hole 8.4. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0056] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "several" means two or more.

[0057] like Figures 1-12 Embodiment 1 of the present invention provides an oil-filled pressure core, comprising a tube seat 1, an O-ring 2, sealant 3, lead wire 4, corrugated diaphragm 5, solder ring 6, ceramic seat, silicon pressure chip 9, silicone oil 10, and pin 11. The ceramic seat includes a first ceramic body 7 and a second ceramic body 8. The tube seat 1 includes a metal base 1.1, a sealing glass 1.2, and leads 1.3. The tube seat 1 includes a positive pressure side (the side closer to the measured medium) and a back pressure side (the side opposite to the measured medium), as shown below. Figure 3The metal base 1.1 is machined with an annular groove 1.1-1, an annular end face 1.1-2, an oil filling hole 1.1-4, a groove 1.1-5, and a vent hole 1.1-6. The oil filling hole 1.1-4 and the vent hole 1.1-6 are both axially opened through holes. Figure 3 As shown. The annular groove 1.1-1 and the annular end face 1.1-2 are located on the positive pressure side of the tube seat 1. The annular groove 1.1-1 is used to place the silicon pressure chip 9, the first ceramic body 7 and the second ceramic body 8. The silicon pressure chip 9 and the first ceramic body 7 are fixed on the bottom surface 1.1-3 inside the annular groove.

[0058] The metal base 1.1 is made of stainless steel, and the leads 1.3 are made of Kovar alloy. The Kovar alloy leads 1.3 are sealed to the metal base 1.1 by high-temperature sintering with the sealing glass 1.2. This allows the tube seat 1 to withstand very high pressures without damaging the glass seal, ensuring reliable pressure resistance and sealing performance. Under very high pressures, the glass seal meets the requirement of a leakage rate ≤1×10⁻⁶. -3 Pa•cm 3 The airtightness requirement is high, with pressure values ​​exceeding 100 MPa. Simultaneously, the glass-sealed tube socket has an insulation resistance ≥10 Ω between the leads and the stainless steel base. 3 A resistance of MΩ or higher ensures that the pressure core achieves high insulation performance.

[0059] The metal base 1.1 is also provided with oil filling holes 1.1-4, which are used for filling with silicone oil. Depending on the measuring pressure and the type of silicon pressure chip, multiple oil filling holes 1.1-4 can be selectively provided on the metal base. After the silicone oil is filled, the pin 11 is sealed and welded to the back pressure side of the oil filling hole 1.1-4 using a piezoresistive welding method, such as... Figure 2 As shown, resistance welding ensures high welding efficiency and reliable sealing. The pin 11 is made of the same stainless steel as the metal base 1.1. The annular groove 1.1-1 of the tube seat 1, the corrugated diaphragm 5, and the pin 11 form a sealed oil-filled cavity, inside which the first ceramic body 7, the second ceramic body 8, and the silicon pressure chip 9 are located. Silicon oil 10, after being dehydrated and degassed, is then heated in a high vacuum environment (vacuum degree 10). -4 Under pressure of Pa, it is injected into the interior of the oil-filled pressure core.

[0060] If the measurement type of the oil-filled pressure core is gauge pressure (pressure relative to the atmosphere), then a vent hole 1.1-6 is machined on the metal base 1.1. When the silicon pressure chip 9 (with a back pressure hole) is bonded to the bottom surface 1.1-3 of the annular groove, the back pressure hole of the silicon pressure chip 9 is aligned with the vent hole 1.1-6 and connected to the atmosphere. If the measurement type of the pressure core is absolute pressure (pressure relative to absolute vacuum), then there is no vent hole on the metal base 1.1, and the silicon pressure chip 9 (without a back pressure hole) is directly bonded to the bottom surface 1.1-3 of the annular groove.

[0061] like Figure 4 The corrugated diaphragm 5 includes an annular plane 5.1, a first domed surface 5.2, and a first corrugation 5.3. The corrugated diaphragm 5 is a rotationally symmetrical structure about a central axis. When subjected to uniform pressure applied by the measured medium, the corrugated diaphragm 5 experiences more balanced force distribution and more precise force transmission. Furthermore, the axial and radial deformation of the corrugated diaphragm 5 due to force is controllable.

[0062] The annular plane 5.1 of the corrugated diaphragm 5 is clamped between the annular end face 1.1-2 and the welding ring 6 on one side of the tube base 1, and is welded together. Specifically, the annular plane 5.1 of the corrugated diaphragm 5 is located between the annular end face 1.1-2 of the metal base 1.1 and the annular end face of the welding ring 6, and the outer diameters of the three annular surfaces are equal. After compression, circumferential welding is performed along their joint, thereby fusing the joint into one piece. Preferably, argon arc welding is used for circumferential welding to ensure the high pressure resistance and airtightness of the corrugated diaphragm 5 after welding.

[0063] The first dome-shaped surface 5.2 of the corrugated diaphragm 5 is located inside the annular plane 5.1. Several annular first corrugations 5.3 are distributed on the first dome-shaped surface 5.2. The first corrugations 5.3 are evenly distributed on the first dome-shaped surface 5.2 at a certain interval.

[0064] The dome-shaped surface, formed by the upward or downward arching of the corrugated diaphragm surface, is a natural pressure-resistant structure (similar to an eggshell). It uniformly converts the pressure applied to the diaphragm surface into thin-film stress within the diaphragm (rather than bending stress), thus minimizing stress concentration. This allows the sensor to withstand pressure overloads and pressure shocks several times its measurement range, and even recover after instantaneously extremely high pressure peaks without deformation or permanent failure. This is crucial for harsh environments such as industrial and military applications.

[0065] Meanwhile, compared to planar structures, dome structures have higher stiffness, which gives the oil-filled pressure core better dynamic response characteristics, enabling it to measure rapidly changing pressure more accurately without distortion due to diaphragm vibration.

[0066] Compared to planar structures, dome structures have a larger surface area, meaning that within a certain working radius (the cross-sectional radius of the pressure-sensing side), the corrugated diaphragm has a larger contact area with the silicone oil, thereby improving the diaphragm's sensitivity in transmitting pressure.

[0067] Specifically, the first dome surface is a spherical cap (referring to the curved surface remaining after a sphere is cut by a plane), an ellipsoidal cap (referring to the curved surface remaining after an ellipsoid is cut by a plane perpendicular to the axis of rotation), or a paraboloid of revolution (referring to the curved surface remaining after a paraboloid of revolution is cut by a plane perpendicular to the axis of rotation).

[0068] Preferably, the first domed surface is a hemispherical surface, and when the working radius is r, the contact area between the planar diaphragm and the silicone oil is approximately πr. 2 The contact area between the hemispherical corrugated diaphragm and the silicone oil is approximately 2πr. 2 It is twice the size of a planar diaphragm, greatly increasing the sensitivity of the oil-filled core. This provides a good solution for situations where the working radius of the pressure core is limited while maintaining high sensitivity.

[0069] To improve the linearity and response sensitivity of the corrugated diaphragm 5, several first corrugations 5.3 are formed on the first dome surface 5.2. In this embodiment, the first corrugations 5.3 are formed by the inward bulge of the corrugated diaphragm 5. Ideally, the corrugated diaphragm 5 uses silicone oil to transmit the working pressure equally to the silicone oil 10 and the silicone pressure chip 9. However, the corrugated diaphragm 5 must deform to transmit pressure, resulting in self-deformation stress. The corrugated structure on the first dome surface 5.2 can reduce the self-deformation stress of the diaphragm and make the stress evenly distributed, thereby improving the linearity and sensitivity of the pressure core.

[0070] The corrugated surface of the corrugated diaphragm can be circular, sinusoidal, triangular, or trapezoidal.

[0071] The corrugated diaphragm is made of 316L stainless steel with a thickness of 0.025~0.05mm. The corrugations are sinusoidal with a depth of 0.1~0.3mm. Taking a hemispherical diaphragm with the first dome surface 5.2 as an example, when the working radius is r and the corrugation spacing is a, a planar diaphragm can theoretically have (r / a) corrugations, while a hemispherical diaphragm can theoretically have πr / 2a≈1.57r / a corrugations. The more corrugations, the better the force transmission performance of the diaphragm.

[0072] The corrugated diaphragm 5 is manufactured using either stamping or high-pressure fluid forming. For example... Figure 9When the corrugated diaphragm 5 is formed by stamping, a two-stage stamping process can be used. First, a first dome-shaped surface 5.2 is formed by stamping, and then a second stamping is performed on the first dome-shaped surface 5.2 to form the first corrugated structure 5.3. Specifically, a circular planar diaphragm is stamped once to form an annular plane 5.1 on the outside, and a desired upward or downward arched dome-shaped arc structure (first dome-shaped surface 5.2) is formed on the inner side of the annular plane 5.1. The dome-shaped surface 5.2 of the corrugated diaphragm 5 is then stamped a second time to form several annular corrugated structures with a certain spacing on the dome-shaped surface 5.2.

[0073] When the corrugated diaphragm 5 is formed by high-pressure fluid, high-pressure gas or liquid is used as the forming medium to apply high pressure to the metal diaphragm, causing the diaphragm blank to undergo plastic deformation and fit tightly with the mold, forming annular planes, dome surfaces and corrugated structures on the diaphragm in one go.

[0074] The first ceramic body 7 and the second ceramic body 8 are both made of alumina (Al2O3) ceramic and are formed by high-temperature sintering.

[0075] like Figure 5 The first ceramic body 7 is a rotating structure, cylindrical in shape. Its first bottom surface 7.4 is flat, and the end face of the first ceramic body 7 facing away from the first bottom surface 7.4 is a first arc-shaped surface 7.9 with a square notch in the middle. A second corrugated structure 7.8 is provided on the first arc-shaped surface 7.9. Figure 6 The second ceramic body 8 has a cuboid structure, its second bottom surface 8.1 is a plane, and the end face of the second ceramic body 8 facing away from the second bottom surface 8.1 is a second arc-shaped surface 8.3. For example... Figure 8 The second arc-shaped surface 8.3 perfectly fills the square gap, meaning that the first arc-shaped surface 7.9 of the first ceramic body 7 and the second arc-shaped surface 8.3 of the second ceramic body 8 face the same side and form a complete second dome-shaped surface structure. Furthermore, the second dome-shaped surface structure formed by the first ceramic body 7 and the second ceramic body 8 matches the size and shape of the first dome-shaped surface 5.2 of the corrugated diaphragm 5, meaning that the normal distance from each point on the dome-shaped surface of the corrugated diaphragm to the dome-shaped surface of the ceramic seat is approximately the same.

[0076] Several second corrugations 7.8 are also provided on the first arc-shaped surface 7.9 of the first ceramic body 7. The second corrugations 7.8 are small convex rings on the first ceramic body 7 facing the corrugated diaphragm 5, and their size and shape match the first corrugations 5.3 on the corrugated diaphragm 5.

[0077] The domed surfaces and corrugations on the corrugated diaphragm 5 match the domed surfaces and corrugations on the ceramic base in size and shape, and their normal distances are similar. On the one hand, this minimizes the amount of oil inside the oil-filled pressure core, improving its nonlinearity and temperature drift characteristics. On the other hand, even when the corrugated diaphragm comes into contact with the ceramic base, it does not adversely affect the shape of the corrugated diaphragm 5 or the measurement accuracy of the oil-filled pressure core when subjected to extreme impacts, vibrations, and alternating pressures from various directions in space. This greatly improves the oil-filled pressure core's resistance to impact and vibration, as well as its dynamic measurement accuracy.

[0078] The first bottom surface 7.4 of the first ceramic body 7 is bonded to the bottom surface 1.1-3 of the annular groove of the metal base 1.1 using sealant 3. The silicon pressure chip 9 has a square structure and is located within the small-diameter section of the stepped hole 7.1 of the first ceramic body 7. The silicon pressure chip 9 is also bonded to the bottom surface 1.1-3 of the annular groove of the metal base 1.1 using sealant 3. The second ceramic body 8 is located within the large-diameter section of the stepped hole 7.1. The second bottom surface 8.1 of the second ceramic body 8 is bonded to the step surface 7.7 of the stepped hole using sealant 3. The side surface 8.2 of the second ceramic body 8 corresponds to the side wall 7.2 of the first ceramic body 7, and the step surface 7.7 provides support for the second ceramic body 8. The sealant 3 is fluorosilicone, and its curing method is room temperature vulcanization (RTV), which ensures the strength and airtightness of the bonding between the ceramic body and the silicon pressure chip 9 and the stainless steel base 1.1.

[0079] The first ceramic body 7 has an oil inlet hole 7.3 for guiding silicone oil into the space between the corrugated diaphragm 5 and the ceramic body. The oil inlet hole 7.3 is aligned with and connected to the oil filling holes 1.1-4 on the tube seat 1. Silicone oil 10 is injected into the oil storage cavity formed by the corrugated diaphragm and the ceramic seat through the oil filling holes 1.1-4 on the metal base 1.1 and the oil inlet hole 7.3 on the first ceramic body 7.

[0080] The second ceramic body 8 has several pressure-guiding holes 8.4, through which the silicone oil in the oil storage cavity flows to the silicon pressure chip 9.

[0081] The first ceramic body 7 is also provided with a lead hole 7.5, and the lead 1.3 on the tube seat 1 extends into the lead hole 7.5, such as... Figure 7 The pin 1.3 is electrically connected to the silicon pressure chip 9 via a lead wire 4. To avoid interference, a lead groove 7.6 for accommodating the lead wire 4 is provided on the stepped surface 7.7 of the stepped hole. The number of pin holes 7.5 corresponds to the number of pins 1.3 on the tube socket 1. The stepped hole 7.1, the oil inlet hole 7.3, and the pin holes 7.5 are all through holes opened along the axial direction. The silicon pressure chip 9 uses a wire bonding process to achieve electrical connection with the pins 1.3.

[0082] like Figures 10-12Embodiment 2 of the present invention provides an oil-filled pressure core with another structure, including a tube seat 1, an O-ring 2, a sealant 3, a lead wire 4, a corrugated diaphragm 5, a solder ring 6, a first ceramic body 7, a second ceramic body 8, a silicon pressure chip 9, silicone oil 10, and a pin 11; the corrugated diaphragm 5 includes an annular plane 5.1, a domed surface 5.2, and corrugations 5.3. The first domed surface 5.2 is located inside the annular plane 5.1 and is a centrally rotationally symmetrical curved surface structure that convexes outward, such as... Figure 10 As shown.

[0083] The first ceramic body 7 and the second ceramic body 8 form a complete, outwardly convex, centrally rotationally symmetrical dome structure. The size and shape of the dome and corrugations of the combined ceramic body structure match the dome and corrugations of the corrugated diaphragm, such as... Figure 10 , Figure 12 As shown.

[0084] In the second embodiment, the first corrugation 5.3 is formed by the corrugated diaphragm 5 protruding outward; the ceramic seat formed by the first ceramic body 7 and the second ceramic body 8 is cup-shaped and inverted on the silicon pressure chip 9; the solder ring 6 is heightened, and both the corrugated diaphragm 5 and the ceramic seat are located in the annular groove formed by the solder ring 6.

[0085] Embodiment 3 of the present invention provides a method for preparing an oil-filled pressure core, comprising the following steps:

[0086] S1. The first ceramic body and the silicon pressure chip are respectively bonded to the metal base of the tube socket, and the adhesive is cured;

[0087] S2. Perform plasma cleaning on the socket after bonding the silicon pressure chip;

[0088] S3. Wire bonding technology is used to achieve electrical connection between the silicon pressure chip and the pins on the socket;

[0089] S4. Adhere the second ceramic body to the first ceramic body and cure the adhesive;

[0090] S5. Install the corrugated diaphragm and welding ring onto the metal base of the pipe seat, and weld the three together using argon arc welding; the corrugated diaphragm forms an oil storage cavity with the first ceramic body and the second ceramic body;

[0091] S6. Place the welded tube seat in a vacuum oven for high-temperature baking to remove moisture, organic residues, etc. from the oil storage cavity;

[0092] S7. Inject silicone oil into the oil reservoir cavity through the oil filling hole on the metal base;

[0093] S8. Seal and weld the pin to the oil filling hole of the metal base.

[0094] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An oil-filled pressure core, characterized in that: The device includes a tube base, a corrugated diaphragm, a ceramic base, and a silicon pressure chip. The corrugated diaphragm, ceramic base, and silicon pressure chip are all mounted on the tube base. An oil storage cavity is formed between the corrugated diaphragm and the ceramic base. The corrugated diaphragm includes a first domed surface, and the ceramic base has a second domed surface with the same curvature as the first domed surface. The oil storage cavity is located between the first domed surface and the second domed surface. The ceramic base also has a pressure-guiding hole for allowing the silicon oil in the oil storage cavity to flow to the silicon pressure chip.

2. The oil-filled pressure core as described in claim 1, characterized in that: The ceramic base includes a first ceramic body and a second ceramic body. The first ceramic body has stepped holes, including a large-diameter section and a small-diameter section. The second ceramic body is located in the large-diameter section, and the silicon pressure chip is located in the small-diameter section. The silicon pressure chip is located below the second ceramic body, and the pressure-guiding hole is located on the second ceramic body. The first ceramic body has a first arc-shaped surface with the same curvature as the first dome surface, and the second ceramic body has a second arc-shaped surface with the same curvature as the first dome surface. The first arc-shaped surface and the second arc-shaped surface are joined together to form a complete second dome surface.

3. The oil-filled pressure core as described in claim 2, characterized in that: The first ceramic body is also provided with a pin hole, and the pins on the tube socket extend into the pin hole. The pins are electrically connected to the silicon pressure chip through leads. The stepped surface of the stepped hole is provided with a lead groove for receiving leads.

4. The oil-filled pressure core as described in claim 2, characterized in that: The first dome-shaped surface is provided with a plurality of first corrugations, each of which is arranged around the central axis of the corrugated diaphragm. The first arc-shaped surface is provided with a plurality of second corrugations, each of which is arranged around the central axis of the first ceramic body. The positions of the second corrugations correspond to those of the first corrugations, and the waveforms and sizes are matched.

5. The oil-filled pressure core as described in claim 4, characterized in that: The cross-sectional shape of the first ripple is circular, sinusoidal, triangular, or trapezoidal.

6. The oil-filled pressure core as described in claim 2, characterized in that: The second ceramic body is fixed in the large-diameter section with sealant, and the first ceramic body and the silicon pressure chip are both fixed on the tube base with sealant.

7. The oil-filled pressure core as described in claim 1, characterized in that: The corrugated diaphragm also includes an annular plane, which surrounds the first dome surface and is located between the end face of the welding ring and the positive pressure side of the tube seat. The annular plane is welded and fixed to the tube seat by the welding ring.

8. The oil-filled pressure core as described in claim 1, characterized in that: The first domed surface is a spherical cap, an ellipsoidal cap, or a paraboloid of revolution.

9. A method for preparing an oil-filled pressure core, characterized in that: Includes the following steps: S1. The first ceramic body and the silicon pressure chip are respectively bonded to the tube socket, and the adhesive is cured. S2. Perform plasma cleaning on the socket after bonding the silicon pressure chip; S3. Wire bonding technology is used to achieve electrical connection between the silicon pressure chip and the pins on the socket; S4. Adhere the second ceramic body to the first ceramic body and cure the adhesive; S5. Install the corrugated diaphragm and welding ring onto the metal base of the pipe seat, and weld the three together; the corrugated diaphragm forms an oil storage cavity with the first ceramic body and the second ceramic body; S6. Place the welded tube seat in a vacuum oven for high-temperature baking to remove moisture and organic residues from the oil storage cavity; S7. Inject silicone oil into the oil reservoir cavity through the oil filling hole on the pipe seat; S8. Seal the oil filling hole of the base.

10. The method for preparing the oil-filled pressure core as described in claim 9, characterized in that: The corrugated diaphragm is manufactured by stamping or high-pressure fluid forming.

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