Dual-channel oil-filled pressure core and preparation method thereof

Abstract

The invention discloses a dual-channel oil-filled pressure core body and a preparation method, and relates to the technical field of pressure core bodies, the dual-channel oil-filled pressure core body comprises a first base assembly, a second base assembly and an integrated circuit board, the first base assembly is provided with a containing cavity and a first groove with opposite openings, and the second base assembly is provided with a second groove; the first groove is communicated with the first oil filling hole to form a first oil filling cavity; the first silicon piezoresistive chip is fixed at the bottom of the first groove, and the first diaphragm seals the opening of the first groove; the second base is provided with a second groove, the second groove is communicated with the second oil filling hole to form a second oil filling cavity, the second silicon piezoresistive chip is fixed at the bottom of the second groove, and the second diaphragm seals an opening of the second groove; the integrated circuit board is in electric signal connection with the first silicon piezoresistive chip and the second silicon piezoresistive chip through the first pin and the second pin. The dual-channel oil-filled pressure core body is simple in structure, high in measurement reliability and capable of meeting the use requirements of different scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure core, in particular to a double-channel oil-filled pressure core and a preparation method. BACKGROUND

[0002] The oil-filled pressure core is made by packaging a silicon piezoresistive pressure sensitive element in a stainless steel shell. With the help of a separation diaphragm and internally filled silicone oil, it can transmit external pressure to the sensitive chip without damage. The chip converts the pressure into an electrical signal output after sensing the pressure and is widely used in key fields such as aerospace and industrial safety systems.

[0003] Currently, to improve the safety and reliability of sensors, a double-chip redundancy design is generally used, that is, two pressure sensitive chips are arranged in one oil-filled cavity. The silicon piezoresistive chip is pressed from the front and the front of the chip faces the separation diaphragm and is bonded near the separation diaphragm at the front end of the core. The circuit is connected through the pin and the signal is transmitted to the circuit board at the rear end of the core. The whole is composed of an oil-filled body, a corrugated diaphragm and two pressure sensitive chips, which can ensure normal operation when a single chip is damaged.

[0004] However, the current double-chip design of the oil-filled pressure core has significant defects. Firstly, the structure and packaging process are complex, and the manufacturing cost is high. Secondly, as an integrated unit combining mechanical, fluid and electronic systems, its reliability is restricted by many factors, making it difficult to meet the reliability requirements of special working conditions. Specifically, in terms of mechanical structure, the corrugated diaphragm with a thickness of not more than 50 microns is prone to irreversible plastic deformation or damage under super-elastic limit pressure. The diaphragm is difficult to weld and is prone to leakage. Strong vibration or impact can also cause mechanical damage to the core. In terms of fluid pressure transmission, the pressure transmission mechanism based on Pascal's law has strict requirements for the internal oil circuit. Contamination of silicone oil, bubble residue or leakage of the oil-filled cavity welding will affect the pressure transmission effect. Therefore, the existing oil-filled pressure core has the technical problems of insufficient applicability and poor measurement reliability. SUMMARY

[0005] The purpose of the present application is to overcome the above technical deficiencies and provide a double-channel oil-filled pressure core and a preparation method to solve the technical problems of insufficient applicability and poor measurement reliability in the prior art.

[0006] To achieve the above technical purpose, the present application adopts the following technical scheme: In a first aspect, the present application provides a double-channel oil-filled pressure core, which comprises a first base assembly, a second base assembly and an integrated circuit board, the first base assembly comprises a first base, a first silicon piezoresistive chip, a first diaphragm and a first pin; the first base is provided with an accommodating cavity with opposite openings and a first recess, the first recess is communicated with a first oil injection hole to form a first oil-filled cavity; the first silicon piezoresistive chip is fixed to the bottom of the first recess and connected with the first pin, and the first diaphragm seals the opening of the first recess; the second base assembly comprises a second base, a second silicon piezoresistive chip, a second diaphragm and a second pin; the second base is provided with a second recess, the second recess is communicated with a second oil injection hole to form a second oil-filled cavity, the second silicon piezoresistive chip is fixed to the bottom of the second recess and connected with the second pin, and the second diaphragm seals the opening of the second recess; the integrated circuit board is electrically connected with the first silicon piezoresistive chip and the second silicon piezoresistive chip through the first pin and the second pin respectively; wherein the second base is located in the accommodating cavity and forms a cavity together with the wall surface of the accommodating cavity, and the first base is provided with a pressure lead hole communicated with the cavity.

[0007] In some embodiments, the bottom of the first recess is provided with a recessed first container groove, and the first silicon piezoresistive chip is fixed to the bottom of the first container groove; the bottom of the second recess is provided with a recessed second container groove, and the second silicon piezoresistive chip is fixed to the bottom of the second container groove.

[0008] In some embodiments, the second base is further provided with a gas permeable hole, which can be used to communicate the back pressure hole of the second silicon piezoresistive chip with the outside.

[0009] In some embodiments, the number of the first pins is multiple, and the multiple first pins are arranged in a circumferential direction of the first base; the number of the second pins is multiple, and the multiple second pins are arranged in a circumferential direction of the second base.

[0010] In some embodiments, the accommodating cavity is provided with a first step surface and a second step surface, the distance between the first step surface and the bottom of the accommodating cavity is greater than the distance between the second step surface and the bottom of the accommodating cavity; the multiple first pins are arranged in a circumferential direction on the second step surface, and the integrated circuit board is fixed on the first step surface.

[0011] In some embodiments, the first base assembly further comprises a first pin, and the first pin seals the opening of the first oil injection hole by pressure resistance welding; the second base assembly further comprises a second pin, and the second pin seals the opening of the second oil injection hole by pressure resistance welding.

[0012] In some embodiments, the first base assembly further comprises a first welding ring, and the first diaphragm is welded between the first welding ring and the first base; the second base assembly further comprises a second welding ring, and the second diaphragm is welded between the second welding ring and the second base.

[0013] In some embodiments, the number of pressure lead holes is multiple, and the multiple pressure lead holes are arranged along the circumference of the first base.

[0014] In some embodiments, the integrated circuit board comprises a circuit board and a first application-specific integrated circuit chip and a second application-specific integrated circuit chip arranged on the circuit board, and the first pin and the second pin are respectively connected to the circuit board.

[0015] In the second aspect, the application further provides a preparation method of the double-channel oil-filled pressure core, which is applied to the preparation of the double-channel oil-filled pressure core. The first base assembly comprises a first welding ring, and the second base assembly comprises a second welding ring. The preparation method comprises the following steps: sealing the first pin and the second pin to the first base and the second base respectively; fixing the first silicon piezoresistive chip at the bottom of the first groove and electrically connecting the first silicon piezoresistive chip with the first pin; fixing the second silicon piezoresistive chip at the bottom of the second groove and electrically connecting the second silicon piezoresistive chip with the second pin; assembling and welding the first diaphragm and the first welding ring to the end face of the first base, and assembling and welding the second diaphragm and the second welding ring to the first end face of the second base; assembling the second base with the welded second diaphragm into the accommodating cavity and welding and fixing the second base; injecting silicon oil into the first oil injection hole and the second oil injection hole to fill the first oil-filled cavity and the second oil-filled cavity, and sealing the first oil injection hole and the second oil injection hole respectively; and electrically connecting the first pin and the second pin with the integrated circuit board respectively.

[0016] Compared with the prior art, the double-channel oil-filled pressure core provided by the application adopts a double-base assembly and a double-oil-filled cavity design, and the second base is nested in the accommodating cavity of the first base. Therefore, the overall structure of the core is simplified, the space utilization is improved, the independent sensing, conversion, transmission and processing of two pressure signals can be realized, the dual-redundancy pressure measurement function is achieved, and the safety and reliability of the core are significantly improved. The bottom of the first groove can effectively support the first silicon piezoresistive chip, and the silicon piezoresistive chip will not fall off under the pressure of the silicon oil. Similarly, the bottom of the second groove can also effectively support the second silicon piezoresistive chip, so that the measurement demand in different pressure scenes can be met, and the applicability and reliability in multiple scenes are improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is an explosion schematic view of the double-channel oil-filled pressure core provided by the embodiment of the application; Figure 2 is a sectional view of the double-channel oil-filled pressure core provided by the embodiment of the application; Figure 3 is a schematic view of the first oil-filled cavity and the second oil-filled cavity provided by the embodiment of the application; Figure 4 is a structural schematic view of the first base provided by the embodiment of the application; Figure 5is a structural schematic view of a second base provided by an embodiment of the present application; Figure 6 is a structural schematic view of a double-channel oil-filled pressure core containing a first pressure measurement circuit and a second pressure measurement circuit provided by an embodiment of the present application; Figure 7 is an electrical schematic diagram of a double-channel oil-filled pressure core provided by an embodiment of the present application; Figure 8 is a flow schematic view of a preparation method of a double-channel oil-filled pressure core provided by an embodiment of the present application.

[0018] Legend of reference signs: 10, double-channel oil-filled pressure core; 100, first base assembly; 110, first base; 111, accommodating cavity; 112, first groove; 1121, first accommodating groove; 113, first oil injection hole; 1131, opening of the first oil injection hole; 114, pressure lead hole; 115, first step surface; 116, second step surface; 117, first base shaft end; 120, first silicon piezoresistive chip; 130, first diaphragm; 140, first solder ring; 150, first pin; 160, cavity; 170, first pin; 180, first sealing glass; 200, second base assembly; 210, second base; 211, second groove; 2111, second accommodating groove; 212, second oil injection hole; 2121, opening of the second oil injection hole; 213, air hole; 214, second base shaft end; 220, second silicon piezoresistive chip; 230, second diaphragm; 240, second solder ring; 250, second pin; 260, second pin; 270, second sealing glass; 300, integrated circuit board; 310, circuit board; 320, first application-specific integrated circuit chip; 330, second application-specific integrated circuit chip; 340, adhesive; 350, bonding wire; 400, silicone oil; 500, preparation method. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0020] Oil-filled pressure cores are widely used in key fields such as aerospace, industrial safety systems, etc.

[0021] In some embodiments, a dual-chip redundancy design is employed, i.e., two pressure-sensitive chips are placed within an oil-filled chamber. This approach suffers from structural complexity, poor measurement reliability, and is unsuitable for measurements in complex and high-pressure environments.

[0022] To address the technical problems of insufficient applicability and poor measurement reliability, this invention provides a dual-channel oil-filled pressure core. This dual-channel oil-filled pressure core has a simple structure, high measurement reliability, and can meet the usage requirements of different scenarios.

[0023] It should be noted that the dual-channel oil-filled pressure core of the present invention is used in, but not limited to, aerospace equipment. For ease of explanation, this invention will only use the application of the dual-channel oil-filled pressure core in aerospace equipment as an example. The principle of the dual-channel oil-filled pressure core in other types of equipment is essentially the same as that in aerospace equipment, and will not be described in detail here.

[0024] This application provides a dual-channel oil-filled pressure core 10, such as... Figures 1 to 5 As shown, the dual-channel oil-filling pressure core 10 includes a first base assembly 100, a second base assembly 200, and an integrated circuit board 300. The first base assembly 100 includes a first base 110, a first silicon piezoresistive chip 120, a first diaphragm 130, and a first pin 170. The first base 110 has a receiving cavity 111 with opposite openings and a first groove 112. The first groove 112 communicates with the first oil filling hole 113 to form a first oil-filling cavity A. The first silicon piezoresistive chip 120 is fixed to the bottom of the first groove 112 and connected to the first pin 170. The first diaphragm 130 closes the opening of the first groove 112. The second base assembly 200 includes a second base 210, a second silicon piezoresistive chip 220, and an integrated circuit board 300. The second base 210 has a second groove 211, which is connected to the second oil injection hole 212 to form a second oil filling cavity B. The second silicon piezoresistive chip 220 is fixed at the bottom of the second groove 211 and connected to the second pin 260. The second diaphragm 230 closes the opening of the second groove 211. The integrated circuit board 300 is electrically connected to the first silicon piezoresistive chip 120 and the second silicon piezoresistive chip 220 through the first pin 170 and the second pin 260, respectively. The second base 210 is located in the receiving cavity 111 and forms a cavity 160 with the wall of the receiving cavity 111. The first base 110 has a pressure-guiding hole 114 that communicates with the cavity 160.

[0025] The first base 110 is provided with a receiving cavity 111, a first groove 112, a first oil injection hole 113, and a pressure inlet hole 114. The material and processing method of the first base 110 are not limited and can be determined according to actual needs. For example, the material of the first base 110 is stainless steel; for example, the first base 110 is a one-piece molded structure.

[0026] The accommodating cavity 111 is used for accommodating the second base 210, and the shape of the accommodating cavity 111 should match the structure of the second base 210, and the specific structure is not limited. For the convenience of description, the accommodating cavity 111 is taken as a cylindrical cavity, and the second base 210 is taken as a cylindrical base for example.

[0027] The accommodating cavity 111 and the first groove 112 are oppositely opened along the axial direction of the first base 110. For example, the opening of the accommodating cavity 111 is upward, and the opening of the first groove 112 is downward. The first diaphragm 130 closes the opening of the first groove 112, so that the first groove 112 forms a flow channel that can flow.

[0028] It should be noted that the first diaphragm 130 can be a corrugated diaphragm. The volume of the silicone oil will shrink under pressure or low temperature environment, and the corrugated diaphragm will be concave inward. The depth of the concave of the first groove 112 should avoid the contact between the corrugated diaphragm and the bottom of the first groove 112.

[0029] The first lead 170 and the first sealing glass 180 are sealed to the first base 110 by high temperature sintering. The material of the first lead 170 is, for example, Kovar alloy. The first silicon piezoresistive chip 120 is connected and fixed to the bottom of the first groove 112, for example, by using adhesive glue 340. The first oil injection hole 113 and the first lead 170 penetrate the first base 110 along the axial direction. One end of the first oil injection hole 113 is closed, and the other end is communicated with the first groove 112. One end of the first lead 170 extends into the first groove 112 and is connected with the first silicon piezoresistive chip 120 through a bonding wire 350. The first oil injection hole 113 and the first groove 112 are communicated to form a first oil filling cavity A.

[0030] It should be noted that the first silicon piezoresistive chip 120 is enclosed in the first oil filling cavity A. The first silicon piezoresistive chip is an absolute pressure chip, and the first pressure signal output by the first silicon piezoresistive chip is an absolute pressure signal. The first silicon piezoresistive chip 120 measures the difference between the silicone oil pressure and the vacuum, that is, the absolute pressure measurement.

[0031] The outer diameter of the second base 210 is the same as the inner diameter of the accommodating cavity 111 of the first base 110. The second base 210 is connected with the edge of the accommodating cavity 111, for example, laser welding, argon arc welding. The cavity 160 is formed between the second base 210 and the bottom of the accommodating cavity 111. The first base 110 is provided with a pressure lead hole 114 communicated with the cavity 160.

[0032] The second base 210 is provided with a second groove 211 and a second oil injection hole 212. The material and processing method of the second base 210 are not limited. For example, the material of the second base 210 is stainless steel; for example, the second base 210 is an integral molding structure.

[0033] The opening of the second groove 211 is downward, and the second diaphragm 230 closes the opening of the second groove 211, so that the second groove 211 forms a flow channel capable of flowing. It should be noted that the second diaphragm 230 can be a corrugated diaphragm, and the depth of the second groove 211 should avoid the corrugated diaphragm from contacting the bottom of the second groove 211.

[0034] The second pin 260 and the second sealing glass 270 are sealed to the second base 210 by high-temperature sintering, and the material of the second pin 260 is, for example, Kovar. The second silicon piezoresistive chip 220 is fixedly connected to the bottom of the second groove 211, for example, by using adhesive 340, and the second oil injection hole 212 and the second pin 260 penetrate the second base 210 along the axial direction. One end of the second oil injection hole 212 is closed, and the other end is in communication with the second groove 211. One end of the second pin 260 extends into the second groove 211 and is connected to the second silicon piezoresistive chip 220 through a bonding wire 350, and the second oil injection hole 212 and the second groove 211 form a second oil-filled cavity B in communication.

[0035] It should be noted that the second silicon piezoresistive chip 220 can be an absolute pressure chip or a gauge pressure chip, which will be described in the following embodiments.

[0036] The integrated circuit board 300 is electrically connected to the first silicon piezoresistive chip 120 and the second silicon piezoresistive chip 220 through the first pin 170 and the second pin 260, respectively, to realize the measurement and transmission of data.

[0037] As shown in Figure 6 The integrated circuit board 300 includes a circuit board 310, a first application-specific integrated circuit chip 320 (first ASIC chip) and a second application-specific integrated circuit chip 330 (second ASIC chip) arranged on the circuit board 310. The first silicon piezoresistive chip 120 is connected to one end of the first pin 170 through a bonding wire 350, and the other end of the first pin 170 is welded to the circuit board 310 and connected to the first ASIC chip on the circuit board 310, forming a first pressure measurement circuit. The second silicon piezoresistive chip 220 is connected to one end of the second pin 260 through a bonding wire 350, and the other end of the second pin 260 is welded to the circuit board 310 and connected to the second ASIC chip on the circuit board 310, forming a second pressure measurement circuit. The components of the two pressure measurement circuits and the formed pressure measurement circuits are independent of each other and do not affect each other, and each pressure measurement circuit can independently complete the pressure measurement and signal processing functions, thereby ensuring that the system will not be affected by the electrical failure of one of the pressure measurement circuits, such as the silicon piezoresistive chip, the bonding wire, the pin, the ASIC chip, etc.

[0038] The electrical principle of the integrated circuit board 300 is as shown in Figure 7As shown, the input pressure P of the measured fluid medium, the first application specific integrated circuit chip 320 on the circuit board 310 is connected with the first silicon piezoresistive chip 120, under the excitation of the power supply, the first pressure measuring circuit outputs signal 1, realizing the conditioning and temperature compensation of the first pressure measuring signal; the second application specific integrated circuit chip 330 on the circuit board 310 is connected with the second silicon piezoresistive chip 220, under the excitation of the power supply, the second pressure measuring circuit outputs signal 2, realizing the conditioning and temperature compensation of the second pressure measuring signal, finally realizing the independent sensing, conversion, transmission and processing of the two pressure signals.

[0039] Therefore, in the embodiment, by adopting the double-base assembly and the double-oil charging cavity design, and nesting the second base 210 in the accommodating cavity 111 of the first base 110, not only the overall structure of the core is simplified, the space utilization is improved, but also the independent sensing, conversion, transmission and processing of the two pressure signals are realized, thereby achieving the dual-redundancy pressure measurement function, and the safety and reliability of the core are significantly improved; the bottom of the first groove 112 can effectively support the first silicon piezoresistive chip 120, and the first silicon piezoresistive chip 120 will not fall off under the pressure of the silicone oil 400, and the bottom of the second groove 211 can also effectively support the second silicon piezoresistive chip 220, so as to meet the measurement requirements in different pressure scenes and improve the applicability and reliability in multiple scenes.

[0040] In some embodiments, as shown in Figure 2 , Figure 4 and Figure 5 , the bottom of the first groove 112 is provided with a recessed first accommodating groove 1121, and the first silicon piezoresistive chip 120 is fixed to the bottom of the first accommodating groove 1121; the bottom of the second groove 211 is provided with a recessed second accommodating groove 2111, and the second silicon piezoresistive chip 220 is fixed to the bottom of the second accommodating groove 2111.

[0041] In the embodiment, the first silicon piezoresistive chip 120 is arranged at the bottom of the first accommodating groove 1121, which can reduce the lateral pressure of the silicone oil 400 around the first silicon piezoresistive chip 120 on the first silicon piezoresistive chip 120, so that the first silicon piezoresistive chip 120 mainly bears the pressure from the front of the silicone oil 400, and the bottom of the first accommodating groove 1121 can provide corresponding support force, thereby reducing the possibility of deviation of the first silicon piezoresistive chip 120, improving the stability of the first silicon piezoresistive chip 120, and improving the measurement accuracy. Similarly, the second silicon piezoresistive chip 220 is arranged at the bottom of the second accommodating groove 2111, which can improve the stability of the second silicon piezoresistive chip 220 and improve the measurement accuracy of the second silicon piezoresistive chip 220.

[0042] In some embodiments, as shown in Figure 2 and Figure 5As shown, the second base 210 is further provided with a gas permeable hole 213, which can be used to communicate the back pressure hole of the second silicon piezoresistive chip 220 with the outside.

[0043] In the present embodiment, if the second silicon piezoresistive chip 220 is enclosed in the second oil-filled cavity B, the second silicon piezoresistive chip 220 is a pressure chip, and the output second pressure signal is a pressure signal. The second silicon piezoresistive chip 220 measures the difference between the silicon oil pressure and the vacuum, i.e. absolute pressure measurement. If the second base 210 is provided with a gas permeable hole 213, the second silicon piezoresistive chip 220 is enclosed in the second oil-filled cavity B, but its back pressure hole communicates with the outside through the gas permeable hole 213, and the second silicon piezoresistive chip 220 is a gauge chip, and the output second pressure signal is a gauge signal. The second silicon piezoresistive chip 220 measures the difference between the silicon oil pressure and the atmospheric pressure, i.e. gauge measurement. The position of the gas permeable hole 213 is not limited, as long as it meets the requirement of communicating with the back pressure hole of the second silicon piezoresistive chip 220, for example, the gas permeable hole 213 is arranged in the middle region of the second base 210.

[0044] In some embodiments, the first silicon piezoresistive chip 120 and the second silicon piezoresistive chip 220 can be of the same type or different types, and thus the pressure measuring type of the double-channel oil-filled pressure chip 10 includes absolute pressure and absolute pressure, and absolute pressure and gauge pressure. For example, the first silicon piezoresistive chip 120 and the second silicon piezoresistive chip 220 are of the same type, and the output pressure difference approaches zero; for example, the first silicon piezoresistive chip 120 and the second silicon piezoresistive chip 220 are of different types, and the output pressure difference is about one atmospheric pressure value. When the deviation of the two output values is too large, it can be determined that at least one of them is faulty or the measurement accuracy is out of tolerance, thereby issuing a warning. Therefore, the double-channel oil-filled pressure chip 10 can realize self-checking function by calculating the difference between the two pressure output signals, thereby improving the reliability of the chip.

[0045] In some embodiments, as shown, Figure 4 The number of the first pins 170 is multiple, and the multiple first pins 170 are arranged at intervals along the circumference of the first base 110; the number of the second pins 260 is multiple, and the multiple second pins 260 are arranged at intervals along the circumference of the second base 210.

[0046] In the present embodiment, the number of the first pins 170 is not limited, for example, 2, 3, 4, etc. The multiple first pins 170 can be arranged at uniform intervals or non-uniform intervals along the circumference of the first base 110. By adopting the design of multiple first pins 170, the damage of a single first pin 170 or the influence of poor contact on the transmission of the measurement signal can be prevented, thereby improving the anti-failure capability and use reliability of the first pressure measuring circuit; similarly, the design of multiple second pins 260 can improve the anti-failure capability and use reliability of the second pressure measuring circuit.

[0047] In some embodiments, as shown in Figure 2 and Figure 4 The accommodating cavity 111 is provided with a first step surface 115 and a second step surface 116, the distance between the first step surface 115 and the bottom of the accommodating cavity 111 is greater than the distance between the second step surface 116 and the bottom of the accommodating cavity 111; a plurality of first pins 170 are arranged on the second step surface 116 in a circumferential direction, and the integrated circuit board 300 is fixed on the first step surface 115.

[0048] In this embodiment, the first step surface 115 and the second step surface 116 are annular step surfaces, the first step surface 115 is located above the second step surface 116, the second base 210 is located in the space formed by the second step surface 116 and the bottom of the accommodating cavity 111, and the top edge of the second base 210 is circumferentially welded at the joint with the second step surface 116, and the welding method is laser welding or argon arc welding. The space between the second step surface 116 and the first step surface 115 is arranged for the first pin 150 used to plug the opening 1131 of the first oil injection hole. The space between the first step surface 115 and the top surface of the first base 110 is arranged for the integrated circuit board 300, thereby effectively improving the space utilization.

[0049] In some embodiments, the first oil injection hole 113 and the second oil injection hole 212 adopt an adjacent design, which facilitates the use of a one-time oil filling process and improves the convenience of oil injection.

[0050] In some embodiments, as shown in Figure 2 The first base assembly 100 further includes a first pin 150, and the first pin 150 closes the opening 1131 of the first oil injection hole by pressure resistance welding; the second base assembly 200 further includes a second pin 250, and the second pin 250 closes the opening 2121 of the second oil injection hole by pressure resistance welding.

[0051] In this embodiment, the first base 110 and the first diaphragm 130 form an open first hollow cavity, the first silicon piezoresistive chip 120 is located in the first hollow cavity, the first oil injection hole opening 1131 is closed by the first pin 150 using pressure resistance welding, and the first oil injection hole opening 1131 is closed by the first pin 150 using pressure resistance welding, thereby forming a sealed first oil filling cavity A. The second base 210 and the second diaphragm 230 form an open second hollow cavity, the second silicon piezoresistive chip 220 is located in the second hollow cavity, the second oil injection hole opening 2121 is closed by the second pin 250 using pressure resistance welding, and the second oil injection hole opening 2121 is closed by the second pin 250 using pressure resistance welding, thereby forming a sealed second oil filling cavity B. By using pressure resistance welding, the efficiency and sealing reliability of the welding can be ensured.

[0052] In some embodiments, the openings of the oil injection holes of the first base 110 and the second base 210 are both located on the same oriented end face. A single oil injection process is employed using the first oil injection hole 113 on the first base 110 and the second oil injection hole 212 on the second base 210, in a high vacuum environment (vacuum degree 10). -4 Under pressure (Pa), silicone oil 400 is injected into the first hollow cavity and the second hollow cavity. During injection, silicone oil 400 enters the first groove 112 through the first injection hole 113, eventually filling the first hollow cavity. Simultaneously, silicone oil 400 enters the second groove 211 through the second injection hole 212, eventually filling the second hollow cavity. A single welding process is used to seal the openings of the injection holes in the first base 110 and the second base 210 to the first pin 150 and the second pin 250 using pressure resistance welding.

[0053] In this embodiment, a single oil filling process and a single pin sealing welding process are adopted, which greatly simplifies the core packaging process and ensures the consistency of silicone oil filling and sealing in the two oil-filled cavities, thereby improving the good consistency and temperature drift characteristics of the two pressure measurements.

[0054] In some embodiments, such as Figure 2 As shown, the first base assembly 100 further includes a first welding ring 140, and a first diaphragm 130 is welded between the first welding ring 140 and the first base 110; the second base assembly 200 further includes a second welding ring 240, and a second diaphragm 230 is welded between the second welding ring 240 and the second base 210.

[0055] In this embodiment, the first welding ring 140 and the first base 110 clamp the first diaphragm 130 in the middle, and the first diaphragm 130 is attached to the shaft end 117 of the first base. Then, they are welded together radially in a circumferential manner. The welding method is, for example, argon arc welding, which can ensure the strength and airtightness of the weld. Similarly, the second welding ring 240 and the second base 210 clamp the second diaphragm 230 in the middle, and the second diaphragm 230 is attached to the shaft end 214 of the second base. Then, they are welded together radially in a circumferential manner. The welding method is also argon arc welding to ensure the strength and airtightness of the weld.

[0056] In some embodiments, such as Figure 4 As shown, there are multiple pressure-inducing holes 114, which are arranged at intervals along the circumference of the first base 110.

[0057] In the embodiment, the fluid medium to be measured is in contact with the second diaphragm 230 through the pressure introduction holes 114 formed on the first base 110. The number of the pressure introduction holes 114 is not limited, for example, 2, 3, 4, etc. The plurality of pressure introduction holes 114 can be uniformly or non-uniformly arranged along the circumference of the first base 110. By adopting the design of the plurality of pressure introduction holes 114, the influence of the blockage of a single pressure introduction hole 114 on the measurement can be prevented, and the fault resistance and use reliability are improved.

[0058] It should be noted that the pressure introduction holes 114 can not only serve as flow channels, but also meet the needs of different scenarios by adjusting the length-diameter ratio (the ratio of the length to the diameter of the pressure introduction hole). For example, when the length-diameter ratio is greater than or equal to 4, the specific ratio can be 4, 5, 6, 7, etc. At this moment, the pressure introduction hole 114 is an elongated hole (damping hole), which can suppress the vibration and impact pressure of the medium, thereby protecting the second diaphragm 230 and the second silicon piezoresistive chip 220. For example, when the length-diameter ratio is less than or equal to 3, the specific ratio can be 3, 2, 1, etc. At this moment, the pressure introduction hole 114 can transmit the medium pressure in real time and accurately, ensuring that the second silicon piezoresistive chip 220 has high dynamic frequency response characteristics.

[0059] The application further provides a preparation method 500 of the double-channel oil-filled pressure core, as shown in Figure 8 The first base assembly 100 includes the first welding ring 140, and the second base assembly 200 includes the second welding ring 240. The preparation method 500 includes the following steps. In step S510, the first lead 170 and the second lead 260 are respectively sealed to the first base 110 and the second base 210.

[0060] Specifically, the first lead 170 and the first sealing glass 180 are sealed to the first base 110 by high-temperature sintering, and the second lead 260 and the second sealing glass 270 are sealed to the second base 210 by high-temperature sintering.

[0061] In step S520, the first silicon piezoresistive chip 120 is fixed to the bottom of the first groove 112 and electrically connected with the first lead 170, and the second silicon piezoresistive chip 220 is fixed to the bottom of the second groove 211 and electrically connected with the second lead 260.

[0062] Specifically, the first silicon piezoresistive chip 120 is pasted on the bottom of the first groove 112, and the lead bonding process is adopted to electrically connect the first silicon piezoresistive chip 120 with one end of the first lead 170. The second silicon piezoresistive chip 220 is pasted on the bottom of the second groove 211, and the lead bonding process is adopted to electrically connect the second silicon piezoresistive chip 220 with one end of the second lead 260.

[0063] Step S530, the first diaphragm 130 and the first welding ring 140 are assembled and welded to the first base shaft end 117, and the second diaphragm 230 and the second welding ring 240 are assembled and welded to the second base shaft end 214.

[0064] Specifically, the first welding ring 140 and the first base 110 sandwich the first diaphragm 130 in the middle, the first diaphragm 130 is attached to the first base shaft end 117, and the three are welded together by argon arc welding; the second welding ring 240 and the second base 210 sandwich the second diaphragm 230 in the middle, the second diaphragm 230 is attached to the second base shaft end 214, and the three are welded together by argon arc welding.

[0065] Step S540, the second base 210 welded with the second diaphragm 230 is assembled into the accommodating cavity 111 and welded and fixed.

[0066] Specifically, the second base 210 welded with the second diaphragm 230 is assembled into the accommodating cavity 111 of the first base 110, and continuous welding is performed at the joint between the edge of the top surface of the second base 210 and the second stepped surface 116 by laser welding or argon arc welding.

[0067] Step S550, silicon oil 400 is injected into the first oil injection hole 113 and the second oil injection hole 212 respectively to fill the first oil-filled cavity A and the second oil-filled cavity B, and the first oil injection hole 113 and the second oil injection hole 212 are sealed respectively.

[0068] Specifically, silicon oil is poured into the core through the oil injection holes on the first base 110 and the second base 210, so that the silicon oil fills the first oil-filled cavity A and the second oil-filled cavity B, for example, the first pin 150 and the second pin 250 are respectively blocked and welded at the openings of the oil injection holes of the first base 110 and the second base 210, forming the first oil-filled cavity A and the second oil-filled cavity B which are independent and sealed from each other.

[0069] Step S560, the first pin 170 and the second pin 260 are respectively electrically connected with the integrated circuit board 300.

[0070] Specifically, the other end of the first pin 170 and the other end of the second pin 260 are respectively welded on the circuit board 310, and the circuit board 310 is adhered on the first base 110, for example, on the first stepped surface 115; the first application specific integrated circuit chip 320 (first ASIC chip) and the second application specific integrated circuit chip 330 (second ASIC chip) on the circuit board 310 respectively perform signal conditioning on the output electrical signals of the first silicon piezoresistive chip 120 and the second silicon piezoresistive chip 220.

[0071] In some embodiments, between step S540 and step S550, the preparation method 500 further comprises step S570 of placing the double-channel oil-charge pressure core 10 in a vacuum oven for high-temperature baking to remove water vapor, organic residues, and the like in the core inner cavity.

[0072] The above description of the specific embodiments of the present application is not intended to limit the scope of the present application. Any other corresponding changes and modifications made according to the technical concept of the present application should be included in the scope of protection of the claims of the present application.

Claims

1. A dual-channel oil-filled pressure core, characterized in that, include: The first base assembly includes a first base, a first silicon piezoresistive chip, a first diaphragm, and a first pin; the first base has a receiving cavity with opposite openings and a first groove, the first groove communicating with a first oil injection hole to form a first oil filling cavity; the first silicon piezoresistive chip is fixed to the bottom of the first groove and connected to the first pin, and the first diaphragm closes the opening of the first groove; The second base assembly includes a second base, a second silicon piezoresistive chip, a second diaphragm, and a second pin; the second base is provided with a second groove, the second groove is connected to a second oil injection hole to form a second oil filling cavity, the second silicon piezoresistive chip is fixed to the bottom of the second groove and connected to the second pin, and the second diaphragm closes the opening of the second groove; The integrated circuit board is electrically connected to the first silicon piezoresistive chip and the second silicon piezoresistive chip through the first pin and the second pin, respectively. The second base is located inside the receiving cavity and forms a cavity with the wall of the receiving cavity. The first base is provided with a pressure-guiding hole that communicates with the cavity.

2. The dual-channel oil-filled pressure core according to claim 1, characterized in that, The bottom of the first groove is provided with a recessed first receiving groove, and the first silicon piezoresistive chip is fixed to the bottom of the first receiving groove; The bottom of the second groove is provided with a recessed second accommodating groove, and the second silicon piezoresistive chip is fixed to the bottom of the second accommodating groove.

3. The dual-channel oil-filled pressure core according to claim 2, characterized in that, The second base is also provided with a vent hole, which can be used to connect the back pressure hole of the second silicon piezoresistive chip to the outside.

4. The dual-channel oil-filled pressure core according to claim 1, characterized in that, The number of first pins is multiple, and the multiple first pins are arranged at intervals along the circumference of the first base; the number of second pins is multiple, and the multiple second pins are arranged at intervals along the circumference of the second base.

5. The dual-channel oil-filled pressure core according to claim 4, characterized in that, The cavity is provided with a first step surface and a second step surface. The distance between the first step surface and the bottom of the cavity is greater than the distance between the second step surface and the bottom of the cavity. A plurality of first pins are arranged circumferentially on the second step surface, and the integrated circuit board is fixed on the first step surface.

6. The dual-channel oil-filled pressure core according to claim 1, characterized in that, The first base assembly also includes a first pin, which seals the opening of the first oil injection hole by pressure resistance welding; The second base assembly also includes a second pin, which seals the opening of the second oil injection hole by pressure resistance welding.

7. The dual-channel oil-filled pressure core according to claim 1, characterized in that, The first base assembly further includes a first welding ring, and the first diaphragm is welded between the first welding ring and the first base; The second base assembly also includes a second welding ring, and the second diaphragm is welded between the second welding ring and the second base.

8. The dual-channel oil-filled pressure core according to claim 1, characterized in that, The number of pressure-guiding holes is multiple, and the multiple pressure-guiding holes are arranged at intervals along the circumference of the first base.

9. The dual-channel oil-filled pressure core according to claim 1, characterized in that, The integrated circuit board includes a circuit board and a first application-specific integrated circuit (ASIC) chip and a second ASIC chip disposed on the circuit board, wherein the first pin and the second pin are respectively connected to the circuit board.

10. A method for preparing a dual-channel oil-filled pressure core, applied to the preparation of the dual-channel oil-filled pressure core according to any one of claims 1-9, characterized in that, The first base assembly includes a first weld ring, the second base assembly includes a second weld ring, and the manufacturing method includes: The first pin and the second pin are respectively sealed to the first base and the second base; The first silicon piezoresistive chip is fixed to the bottom of the first groove and electrically connected to the first pin; the second silicon piezoresistive chip is fixed to the bottom of the second groove and electrically connected to the second pin. The first diaphragm and the first welding ring are assembled and welded to the first base shaft end, and the second diaphragm and the second welding ring are assembled and welded to the second base shaft end; The second base, to which the second diaphragm is welded, is assembled into the receiving cavity and welded in place; Silicone oil is injected into the first oil injection hole and the second oil injection hole respectively until the first oil filling cavity and the second oil filling cavity are filled, and the first oil injection hole and the second oil injection hole are sealed respectively; The first pin and the second pin are electrically connected to the integrated circuit board, respectively.

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