Sensor based on solid-phase diffusion of metals and method of processing

Abstract

This invention discloses a sensor based on metal solid-phase diffusion and its processing method. The diaphragm fixing assembly includes a base and a connecting ring disposed on the outer wall of the diaphragm. A base cavity is provided on the lower end face of the base, and a circuit board is assembled within the base cavity. An annular boss is provided between the bottom surface of the base cavity and the top surface of the circuit board. The base is made of a first metal material. The circuit board is made of a second metal material with a surface coating forming a metal film layer. The annular boss is made of either the first or second metal material, wherein the melting point of the second metal is higher than that of the first metal. A metal solid-phase diffusion layer is formed between the annular boss and the bottom surface of the base cavity in contact with it for sealing, or a metal solid-phase diffusion layer is formed between the annular boss and the metal film layer for sealing. The above sensor, by setting the annular boss and forming a metal solid-phase diffusion layer for sealing, improves the reliability of the seal between the circuit board and the base cavity, and enhances the sealing performance of the oil cavity.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a sensor based on solid-phase diffusion in metals and its fabrication method. Background Technology

[0002] To transmit minute deformations, high-precision sensors incorporate an oil cavity between a diaphragm and a sensing element. This oil cavity transmits the diaphragm's deformation to the sensing element, enabling it to detect the deformation and generate a signal. Since the vibration deformation needs to be transmitted to the sensing chip on the circuit board via the oil within the cavity, a high degree of sealing is crucial. However, current technologies typically use adhesive bonding or welding of stainless steel to the circuit board to fix the board to the base and form the oil cavity. These methods cannot reliably seal the oil cavity, resulting in poor sealing and sensor failure, thus affecting the sensor's reliability during use. Therefore, existing sensor structures suffer from poor oil cavity sealing. Summary of the Invention

[0003] The present invention provides a sensor and processing method based on metal solid-phase diffusion, which aims to solve the problem of poor oil cavity sealing in the sensor structure of the prior art.

[0004] In a first aspect, the present invention discloses a sensor based on metal solid-phase diffusion, wherein the sensor includes a pressure cap, a diaphragm and a base;

[0005] A support ring is provided at the top edge of the base, and a crimping ring is provided at the outer edge of the crimping cover. The support ring and the crimping ring are respectively crimped onto both sides of the diaphragm. The side of the crimping cover facing the diaphragm has an inwardly recessed funnel-shaped groove. The top of the crimping cover has a crimping cover through hole that communicates with the funnel-shaped groove. The bottom opening of the funnel-shaped groove is connected to the side wall of the crimping ring. The side wall of the funnel-shaped groove is inclined from the crimping ring toward the crimping cover through hole.

[0006] The lower end face of the base is provided with a base cavity, and the upper end face of the base is provided with a base through hole communicating with the base cavity; the circuit board is assembled in the base cavity; an annular boss is provided between the bottom surface of the base cavity and the top surface of the circuit board; the base is made of a first metal material; the circuit board is made of a second metal material and a metal film layer is formed on its surface; the annular boss is made of either the first metal material or the second metal material, wherein the melting point of the second metal is higher than that of the first metal; a metal solid-phase diffusion layer is formed between the annular boss and the bottom surface of the base cavity in contact with it for sealing, or a metal solid-phase diffusion layer is formed between the annular boss and the metal film layer for sealing;

[0007] There is a gap between the diaphragm and the upper surface of the base; the gap is connected to the through hole of the base to form a T-shaped oil cavity, and oil is injected into the T-shaped oil cavity; the circuit board is provided with a circuit board through hole connected to the through hole of the base; a sealing metal ball is provided at the opening of the circuit board through hole.

[0008] In a second aspect, the present invention discloses a processing method for manufacturing a sensor as described in the first aspect, wherein the processing method includes:

[0009] The circuit board is assembled into the recess of the base, and pressure is applied at both ends to press the circuit board into the recess of the base. The applied pressure is not less than 120 kg.

[0010] While continuously applying pressure, the base and the circuit board are discharged and heated to obtain a metal solid phase diffusion layer formed based on metal solid phase diffusion. The discharge current is 5-30A and the discharge duration is 10-1000ms.

[0011] The diaphragm is assembled onto the support ring of the base, the pressure cap is assembled onto the diaphragm, and the contact surfaces on the upper and lower sides of the diaphragm are welded and fixed.

[0012] After oil is injected into the T-shaped oil cavity through the circuit board through-hole, molten metal balls are used to fill the opening of the circuit board through-hole to form a sealing metal ball.

[0013] This invention discloses a sensor and its processing method based on metal solid-phase diffusion. The diaphragm fixing assembly includes a base and a connecting ring disposed on the outer wall of the diaphragm. A base cavity is provided on the lower end face of the base, and a circuit board is assembled within the base cavity. An annular boss is provided between the bottom surface of the base cavity and the top surface of the circuit board. The base is made of a first metal material. The circuit board is made of a second metal material with a surface coating forming a metal film layer. The annular boss is made of either the first or second metal material, wherein the melting point of the second metal is higher than that of the first metal. A metal solid-phase diffusion layer is formed between the annular boss and the bottom surface of the base cavity in contact with it for sealing, or a metal solid-phase diffusion layer is formed between the annular boss and the metal film layer for sealing. The above sensor, by providing the annular boss and sealing with a metal solid-phase diffusion layer, improves the reliability of the seal between the circuit board and the base cavity, thereby improving the sealing performance of the oil cavity. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is an overall structural diagram of the sensor provided in an embodiment of the present invention;

[0016] Figure 2 Another overall structural diagram of the sensor provided in an embodiment of the present invention;

[0017] Figure 3 A cross-sectional structural diagram of the sensor provided in an embodiment of the present invention;

[0018] Figure 4 This is a partial exploded view of the sensor provided in an embodiment of the present invention;

[0019] Figure 5 A flowchart illustrating the processing method provided in an embodiment of the present invention.

[0020] Reference numerals: 1. Crimping cap; 2. Diaphragm; 3. Base; 31. Support ring; 11. Crimping ring; 12. Trumpet-shaped groove; 13. Crimping cap through hole; 32. Base cavity; 33. Base through hole; 4. Circuit board; 41. Circuit board through hole; 42. Sealing metal ball; 34. Base flange; 341. Clear side; 35. Side groove; 43. Circuit board protrusion; 5. Annular boss. Detailed Implementation

[0021] 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, not all, of the embodiments of the present invention. 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.

[0022] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and, or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and, or collections thereof.

[0023] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0024] It should also be further understood that the terms “and” and “or” as used in this specification and the appended claims refer to any combination of one or more of the associated listed items and all possible combinations, and include such combinations.

[0025] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0026] This invention discloses a sensor based on solid-state diffusion in metals, such as... Figure 1 and Figure 2As shown, the sensor includes a crimping cover 1, a diaphragm 2, and a base 3. A support ring 31 is provided at the top edge of the base 3, and a crimping ring 11 is provided at the outer edge of the crimping cover 1. The support ring 31 and the crimping ring 11 are respectively crimped onto both sides of the diaphragm 2. The side of the crimping cover 1 facing the diaphragm 2 has an inwardly recessed funnel-shaped groove 12. The top of the crimping cover 1 has a crimping cover 1 through hole communicating with the funnel-shaped groove 12. The bottom opening of the funnel-shaped groove 12 is connected to the side wall of the crimping ring 11. The side wall of the funnel-shaped groove 12 is inclined from the crimping ring 11 towards the crimping cover 1 through hole. The lower end face of the base 3 has a base 3 cavity, and the upper end face of the base 3 has a base 3 through hole communicating with the base 3 cavity. The circuit board 4 is assembled inside the base 3 cavity. An annular protrusion 5 is provided between the bottom surface of the concave cavity and the top surface of the circuit board 4; the base 3 is made of a first metal material; the circuit board 4 is made of a second metal material and a metal film is formed by surface coating; the annular protrusion 5 is made of either the first or the second metal material, wherein the melting point of the second metal is higher than that of the first metal; a metal solid diffusion layer is formed between the annular protrusion 5 and the bottom surface of the concave cavity of the base 3 for sealing, or a metal solid diffusion layer is formed between the annular protrusion 5 and the metal film for sealing; there is a gap between the diaphragm 2 and the upper end face of the base 3; the gap is connected to the through hole of the base 3 to form a T-shaped oil cavity, and oil is injected into the T-shaped oil cavity; the circuit board 4 is provided with a through hole of the circuit board 4 connected to the through hole of the base 3; a sealing metal ball 42 is provided at the opening of the through hole of the circuit board 4.

[0027] The sensor disclosed in this application consists of a crimping cover 1, a diaphragm 2, and a base 3. The diaphragm 2 is crimped and fixed between the crimping cover 1 and the base 3. In specific applications, the diameter of the diaphragm 2 can be set to be equal to the outer diameter of both the crimping cover 1 and the base 3, thereby improving the crimping and fixing effect. A crimping ring 11 is provided on the outer edge of the crimping cover 1. The crimping ring 11 is a circular structure formed by protruding outward toward the diaphragm 2. A support ring 31 is provided at the top edge of the base 3. The support ring 31 also protrudes outward toward the diaphragm 2. Thus, the support ring 31 and the crimping ring 11 press the diaphragm 2 together from both sides. The side of the crimping cover 1 facing the diaphragm 2 is recessed inward to form a funnel-shaped groove 12, the specific structure of which is as follows. Figure 3 As shown, one end of the smaller opening of the horn-shaped groove 12 is connected to the through hole 13 of the crimping cover, and one end of the larger opening of the horn-shaped groove 12 (that is, the bottom opening of the horn-shaped groove 12) is connected to the side wall of the crimping ring 11. The side wall of the horn-shaped groove 12 is an inclined surface.

[0028] The specific structure is as follows: Figure 3As shown, the lower end face of the base 3 is provided with a base cavity 32, and the upper end face of the base 3 is provided with a base through hole 33 that communicates with the base cavity 32; the circuit board 4 is assembled in the base cavity 32; there is a gap between the diaphragm 2 and the upper end face of the base 3; the gap communicates with the base through hole 33 to form a T-shaped oil cavity, and oil is injected into the T-shaped oil cavity; the circuit board 4 is provided with a circuit board through hole 41 that communicates with the base through hole 33; a sealing metal ball 42 is provided at the opening of the circuit board through hole 41.

[0029] like Figure 3 and Figure 4 As shown, to achieve a reliable seal between the recess of the base 3 and the circuit board 4, an annular boss 5 can be provided between the bottom surface of the recess of the base 3 and the top surface of the circuit board 4. The base 3 is made of a first metal material; the circuit board 4 is made of a second metal material with a surface coating forming a metal film layer. The annular boss 5 is made of either the first or second metal material, with the second metal having a higher melting point than the first metal. A metal solid-phase diffusion layer is formed between the annular boss 5 and the bottom surface of the recess of the base 3 for sealing, or a metal solid-phase diffusion layer is formed between the annular boss 5 and the metal film layer for sealing. A contact surface is formed between the surface of the annular boss 5 and the bottom surface of the recess of the base 3, or between the surface of the annular boss 5 and the metal film layer. The physical properties between the two metals can be used to heat this contact surface, thereby generating a metal solid-phase diffusion layer between the two metals. This metal solid-phase diffusion layer is then used to firmly connect the circuit board 4 and the recess of the base 3, thus sealing the T-shaped oil cavity.

[0030] The lower end face of the base 3 is provided with a base cavity 32, and the upper end face of the base 3 is provided with a base through hole 33. The inner diameter of the base cavity 32 is larger than the inner diameter of the base through hole 33. The circuit board 4 is assembled in the base cavity 32. Since the edge of the diaphragm 2 is pressed onto the support ring 31, a small gap is formed between the diaphragm 2 and the upper end face of the base 3. The gap is connected to the base through hole 33 to form a T-shaped oil cavity. To facilitate oil injection and sealing of the T-shaped oil cavity, the opening of the circuit board through hole 41 can be sealed by a sealing metal ball 42, thereby sealing the T-shaped oil cavity. Oil is injected into the T-shaped oil cavity. The opening of the circuit board through hole 41 is provided with a sealing metal ball 42. The metal ball can be a solder ball or a metal ball prepared from other metals that are solid at room temperature.

[0031] The diaphragm 2, base 3, and pressure cap 1 are all made of aluminum or aluminum alloy. Laser melting welding can be used between the diaphragm 2 and base 3, and between the diaphragm 2 and pressure cap 1, at a welding temperature of 700-1000℃. Compared to welding stainless steel (which requires temperatures above 1400℃), using aluminum or aluminum alloy to manufacture the diaphragm 2, base 3, and pressure cap 1 significantly reduces the welding temperature, preventing excessive heat conduction to one side of the circuit board 4 and thus avoiding damage to the sensor components on the circuit board 4. This improves the yield rate of sensor production. The circuit board 4 can be a ceramic plate made from ceramic materials.

[0032] The flared groove 12 with its inclined surface facilitates the cleaning of oil generated during the oiling process. Furthermore, the crimping cap 1 with the flared groove 12 significantly increases the structural strength of the diaphragm 2 during crimping, reducing deformation of the diaphragm 2 during welding and thus improving the application effect of sensing and detection through the diaphragm 2. The crimping cap 1 with the flared groove 12 also absorbs heat generated during welding and use, making the sensor performance more stable and improving its effectiveness. Moreover, since the crimping cap 1 covers the diaphragm 2, it provides comprehensive protection for the diaphragm 2, preventing deformation caused by contact with the central area of ​​the diaphragm 2 during production, transportation, and use, thereby improving the reliability of the diaphragm 2 assembly and fixation.

[0033] In a more specific embodiment, the surface of the annular boss 55 is provided with an annular contact surface, the width of which is not less than 0.5 mm. Specifically, the first metal material is aluminum, and the second metal material is iron plated with nickel or iron plated with gold.

[0034] Specifically, the surface of the annular boss 55 forms an annular contact surface, which is a plane and has a width of not less than 0.5 mm. By setting an annular contact surface of a certain width, the contact area corresponding to the annular contact surface is increased, that is, the diffusion area of ​​solid-phase diffusion between metals is increased, further improving the reliability of sealing achieved through the metal solid-phase diffusion layer. In a specific setting, the first metal material can be aluminum, and the second metal material can be iron plated with nickel or iron plated with gold. In the specific embodiment of this application, the first metal material is aluminum, and the second metal material is iron plated with gold, then the metal solid-phase diffusion layer formed by metal solid-phase diffusion is a gold-aluminum alloy; similarly, the circuit board can be a nickel-plated iron circuit board or a gold-plated iron circuit board, then the metal film layer formed by the coating is a nickel layer or a gold layer.

[0035] In a more specific embodiment, the bottom surface of the recessed cavity of the base 3 protrudes outward to form the annular boss 5, or the surface layer of the circuit board 4 protrudes outward to form the annular boss 5. The top of the cross-section of the annular boss 5 is trapezoidal.

[0036] Furthermore, the bottom surface of the recessed cavity of the base 3 can be configured to protrude outward to form an annular boss 5. This configuration is illustrated in a specific embodiment of this application, allowing for solid-phase metal diffusion between the annular boss 5 and the metal film layer of the circuit board 4. Alternatively, the surface layer of the circuit board 4 can be configured to protrude outward to form the annular boss 5. The outer surface of the annular boss 5 can then be coated with a second metal material to form a metal film layer, and solid-phase metal diffusion can also occur between the bottom surface of the recessed cavity of the base 3 and the outer surface of the annular boss 5. In a specific embodiment, the top of the cross-section of the annular boss 5 can be trapezoidal. The waist of the trapezoid can serve as a heating focal point for discharge heating, thereby improving the accuracy of the solid-phase metal diffusion layer formation position and enhancing the reliability of sealing using the annular boss 5 to form the solid-phase metal diffusion layer. Its cross-sectional structure is as follows: Figure 3 As shown.

[0037] Furthermore, before assembling the circuit board 4 into the base cavity 32 for sealing and fixing, the surface of the annular boss 5 and the surface of another component in contact with the annular boss 5 (such as the surface of the circuit board 4 or the bottom surface of the base cavity 32) can be pretreated, such as removing surface contaminants and oxide films, to reduce the roughness of the metal surface and thereby further improve the quality of the formed metal solid phase diffusion layer.

[0038] In a specific embodiment, the ratio between the diameter of the through hole 13 of the crimping cap and the inner diameter of the crimping ring 11 is 1:5-10. Specifically, the angle between the sidewall of the trumpet-shaped groove 12 and the upper end face of the diaphragm 2 is 10-28°. The width of the crimping ring 11 is equal to the width of the support ring 31.

[0039] Specifically, the ratio between the diameter of the through hole 13 of the crimping cap and the inner diameter of the crimping ring 11 can be set to 1:5-10, that is, the diameter of the through hole 13 of the crimping cap is 1 / 5 to 1 / 10 of the inner diameter of the crimping ring 11. By reasonably setting the ratio between the diameter of the through hole 13 of the crimping cap and the inner diameter of the crimping ring 11, the cleaning effect on residual oil inside can be further improved. Furthermore, the angle between the side wall of the funnel-shaped groove 12 and the upper end face of the diaphragm 2 can be set to 10-28°, preferably, the angle between the side wall of the funnel-shaped groove 12 and the upper end face of the diaphragm 2 can be set to 18-25°. The width of the crimping ring 11 can be set to be equal to the width of the support ring 31, thereby improving the effect of crimping and fixing the diaphragm 2.

[0040] In a specific embodiment, the width of the crimping ring 11 is more than twice the thickness of the diaphragm 2. Specifically, the height of the crimping ring 11 is greater than the height of the support ring 31. The height of the crimping ring 11 is 1.5-3.6 times the height of the support ring 31.

[0041] Furthermore, to improve the sealing performance after the crimping ring 11 and the diaphragm 2 are welded, the width of the crimping ring 11 can be set to be more than twice the thickness of the diaphragm 2. In a preferred embodiment, the width of the crimping ring 11 can be set to be 2.5-5 times the thickness of the diaphragm 2.

[0042] Furthermore, the height of the crimping ring 11 can be set to be greater than the height of the support ring 31. In a preferred embodiment, the height of the crimping ring 11 can be set to 1.5-3.6 times the height of the support ring 31. This setting helps to reduce the width of the gap between the diaphragm 2 and the upper end face of the base 3, thereby improving the effect of vibration transmission of oil in the T-shaped oil cavity and improving the sensitivity of the sensor for sensing and detection.

[0043] In a specific embodiment, a side groove 35 is provided on one side of the base cavity 32; a circuit board protrusion 43 adapted to the side groove 35 is provided on the circuit board 4. Specifically, a base flange 34 is also provided on the outer side wall of the base 3. One side of the base flange 34 is vertically cut to form a clearance side 341; the clearance side 341 and the side groove 35 of the base cavity 32 are located on the same side.

[0044] The circuit board 4 can be fixed in the base cavity 32 by bonding, welding or pressing with a pressure ring. When assembling the circuit board 4 onto the base 3, to improve the tightness of the assembly, a side groove 35 can be provided on one side of the base cavity 32, and a circuit board protrusion 43 can be provided on the circuit board 4. The specific structure is as follows. Figure 2 and Figure 3 As shown. This structure allows the circuit board 4 to be more tightly and securely mounted within the base 3, preventing rotational displacement during the bonding process. Furthermore, the circuit board 4 can be positioned by the mating of the protrusion 43 and the side groove 35 during assembly. Even if the circuit board 4 is rotated to the appropriate position and mounted within the base 3, this method ensures that each circuit board 4 is rotated to the same angle and mounted within the base 3, improving the consistency of the orientation of each sensing component (including the sensing chip and connecting leads) on the circuit board 4. This allows for rapid differentiation of the types of components on the circuit board 4 by obtaining the orientation of different sensing components (especially the connecting leads), improving the efficiency and accuracy of fixing and connecting the circuit board 4.

[0045] Specifically, to further improve the stability of the sensor assembly, a base flange 34 can be provided on the outer side wall of the base 3. The base flange 34 is flush with the bottom surface of the base 3. The specific structure is as follows: Figure 1 and Figure 2As shown. Furthermore, to improve the accuracy of positioning the connecting leads on the circuit board 4 of the sensor, a clearance side 341 can be provided on one side of the base flange 34. The specific structure of the clearance side 341 is as follows... Figure 2 As shown, the side relief side 341 and the side groove 35 of the base cavity 32 are located on the same side, that is, the direction of the protrusion of the side groove 35 is directly opposite to the side relief side 341. Therefore, the position of the side groove 35 can be accurately determined by the position of the side relief side 341.

[0046] This invention also discloses a processing method for manufacturing sensors as described in the above embodiments. Figure 5 As shown, the processing method specifically includes steps S110 to S140.

[0047] S110. Assemble the circuit board in the recessed cavity of the base, and apply pressure at both ends to press the circuit board into the recessed cavity of the base, the applied pressure being not less than 120 kg;

[0048] The circuit board can be fixedly assembled into the recessed cavity of the base, and pressure is applied to both ends of the device formed by the combination of the circuit board and the recessed cavity, thereby pressing the circuit board tightly into the recessed cavity of the base. The applied pressure is not less than 120 kg.

[0049] S120. While continuously applying pressure, discharge heating is performed on the base and the circuit board to obtain a metal solid phase diffusion layer formed based on metal solid phase diffusion. The discharge current is 5-30A and the discharge duration is 10-1000ms.

[0050] While continuously applying pressure, the base and the circuit board are subjected to discharge heating to obtain a metal solid-phase diffusion layer formed based on metal solid-phase diffusion. This metal solid-phase diffusion layer can seal the contact surface of the annular boss. The discharge current for discharge heating is 5–30 A, and the discharge duration is 10–1000 ms. The principle of metal solid-phase diffusion is that under temperature stress, Au and Al at the interface can diffuse into each other, producing intermetallic compounds. There are five types of intermetallic compounds formed when gold and aluminum come into contact: Au4Al, Au5Al2, Au2Al, AuAl, and AuAl2. Among them, AuAl2 (commonly known as purple spot) is a good conductor; its resistivity at 300 K is 8 × 10⁻⁶. -6 With a melting point of 1060℃ and Ω·cm, the metal solid-phase diffusion layer formed in this application is a compound of this type. Au2Al (commonly known as white spot) is a very brittle insulator with a melting point of only 624℃, posing a significant hazard.

[0051] S130. The diaphragm is assembled onto the support ring of the base, the pressure cap is assembled onto the diaphragm, and the contact surfaces on the upper and lower sides of the diaphragm are welded and fixed.

[0052] The diaphragm is pressed and assembled onto the support ring of the base, with the top surface of the support ring abutting against the bottom surface of the diaphragm. The pressing cap is then assembled onto the diaphragm, with the pressing ring at the bottom of the pressing cap abutting against the top surface of the diaphragm. The contact surfaces on the upper and lower sides of the diaphragm are welded and fixed, that is, the diaphragm is welded and fixed to the support ring and the pressing ring respectively. The welding operation is laser melting welding, with a welding temperature of 700–1000°C. The pressure applied during the pressing and assembly of the diaphragm is 100–500 kg.

[0053] S140. After injecting oil into the T-shaped oil cavity through the circuit board through hole, molten metal balls are used to fill the opening of the circuit board through hole to form a sealing metal ball.

[0054] After the diaphragm is fixed and assembled, oil can be injected into the T-shaped oil cavity through the circuit board through hole. Then, molten metal balls are used to fill the opening of the circuit board through hole. After the molten metal balls are cooled and cut, they form sealing metal balls and achieve a tight seal at the opening of the circuit board through hole.

[0055] This invention discloses a sensor and its processing method based on metal solid-phase diffusion. The diaphragm fixing assembly includes a base and a connecting ring disposed on the outer wall of the diaphragm. A base cavity is provided on the lower end face of the base, and a circuit board is assembled within the base cavity. An annular boss is provided between the bottom surface of the base cavity and the top surface of the circuit board. The base is made of a first metal material. The circuit board is made of a second metal material with a surface coating forming a metal film layer. The annular boss is made of either the first or second metal material, wherein the melting point of the second metal is higher than that of the first metal. A metal solid-phase diffusion layer is formed between the annular boss and the bottom surface of the base cavity in contact with it for sealing, or a metal solid-phase diffusion layer is formed between the annular boss and the metal film layer for sealing. The above sensor, by providing the annular boss and sealing with a metal solid-phase diffusion layer, improves the reliability of the seal between the circuit board and the base cavity, thereby improving the sealing performance of the oil cavity.

[0056] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A sensor based on solid-state diffusion in metals, characterized in that, The sensor includes a pressure cap, a diaphragm, and a base; A support ring is provided at the top edge of the base, and a crimping ring is provided at the outer edge of the crimping cover. The support ring and the crimping ring are respectively crimped onto both sides of the diaphragm. The side of the crimping cover facing the diaphragm has an inwardly recessed funnel-shaped groove. The top of the crimping cover has a crimping cover through hole that communicates with the funnel-shaped groove. The bottom opening of the funnel-shaped groove is connected to the side wall of the crimping ring. The side wall of the funnel-shaped groove is inclined from the crimping ring toward the crimping cover through hole. The lower end face of the base has a base cavity, and the upper end face of the base has a base through hole communicating with the base cavity; the circuit board is assembled in the base cavity; an annular boss is provided between the bottom surface of the base cavity and the top surface of the circuit board; the base is made of a first metal material; the circuit board is made of a second metal material and has a surface coating to form a metal film layer; the annular boss is made of either the first or the second metal material, wherein the melting point of the second metal is higher than that of the first metal; a metal solid-phase diffusion layer is formed between the annular boss and the bottom surface of the base cavity in contact with it for sealing, or a metal solid-phase diffusion layer is formed between the annular boss and the metal film layer for sealing; There is a gap between the diaphragm and the upper surface of the base; the gap is connected to the through hole of the base to form a T-shaped oil cavity, and oil is injected into the T-shaped oil cavity; the circuit board is provided with a circuit board through hole connected to the through hole of the base; a sealing metal ball is provided at the opening of the circuit board through hole; the first metal material is aluminum, and the second metal material is iron plated with gold; the formed metal solid phase diffusion layer is a gold-aluminum alloy.

2. The sensor based on metal solid-phase diffusion according to claim 1, characterized in that, The surface of the annular boss is provided with an annular contact surface, the width of which is not less than 0.5 mm.

3. The sensor based on metal solid-phase diffusion according to claim 2, characterized in that, The bottom surface of the base cavity protrudes outward to form the annular boss, or the surface layer of the circuit board protrudes outward to form the annular boss.

4. The sensor based on metal solid-phase diffusion according to claim 3, characterized in that, The top of the cross-section of the annular boss is trapezoidal.

5. The sensor based on metal solid-phase diffusion according to any one of claims 1-4, characterized in that, The ratio between the diameter of the through hole of the crimping cap and the inner diameter of the crimping ring is 1:5-10.

6. The sensor based on metal solid-phase diffusion according to any one of claims 1-4, characterized in that, The angle between the sidewall of the trumpet-shaped groove and the upper surface of the diaphragm is 10-28°.

7. The sensor based on metal solid-phase diffusion according to any one of claims 1-4, characterized in that, The width of the crimping ring is equal to the width of the support ring.

8. The sensor based on metal solid-phase diffusion according to any one of claims 1-4, characterized in that, The width of the crimping ring is more than twice the thickness of the diaphragm.

9. A processing method, said processing method being used to process and manufacture the sensor as described in any one of claims 1-8, characterized in that, The processing method includes: The circuit board is assembled into the recess of the base, and pressure is applied at both ends to press the circuit board into the recess of the base. The applied pressure is not less than 120 kg. While continuously applying pressure, the base and the circuit board are discharged and heated to obtain a metal solid phase diffusion layer formed based on metal solid phase diffusion. The discharge current is 5-30A and the discharge duration is 10-1000ms. The diaphragm is assembled onto the support ring of the base, the pressure cap is assembled onto the diaphragm, and the contact surfaces on the upper and lower sides of the diaphragm are welded and fixed. After oil is injected into the T-shaped oil cavity through the circuit board through-hole, molten metal balls are used to fill the opening of the circuit board through-hole to form a sealing metal ball.

Images