CN114354034B

CN114354034B - Pressure sensor and manufacturing method

Info

Publication number: CN114354034B
Application number: CN202111618204.8A
Authority: CN
Inventors: 常文博; 左晓军; 李贝; 耿晓珂; 陈振玲
Original assignee: China Academy of Aerospace Aerodynamics CAAA
Current assignee: China Academy of Aerospace Aerodynamics CAAA
Priority date: 2021-12-27
Filing date: 2021-12-27
Publication date: 2024-07-23
Anticipated expiration: 2041-12-27
Also published as: CN114354034A

Abstract

A pressure sensor and a method of manufacturing the same, the pressure sensor comprising: the shell is in a cylindrical shape with one end open and the other end closed; the conductive pins are inserted at the other end of the shell in parallel to the axial direction of the shell; the sensing element is arranged in the shell and comprises a first cylinder and a second cylinder which are communicated in sequence, one end of the first cylinder, which is away from the second cylinder, is closed, and one end surface of the first cylinder is provided with a plurality of resistors and a plurality of bonding pads which are electrically connected with the resistors; a lead element located within the housing and connected to the first cylinder of the sensing element; and the conductive bent needle is inserted into the lead element, one end of the conductive bent needle is electrically connected with the conductive needle, and the other end of the conductive bent needle is electrically connected with the bonding pad. The pressure sensor provided by the invention utilizes the lead element to replace the circuit board to communicate the bonding pad of the sensitive element with an external cable, so that the high temperature resistance of the sensor is greatly improved, the environmental pressure measurement requirement of a high temperature or wide temperature area is met, and the pressure sensor is suitable for various occasions of high pressure measurement in a high temperature environment.

Description

Pressure sensor and manufacturing method

Technical Field

The invention belongs to the technical field of sensors, and particularly relates to a pressure sensor and a manufacturing method thereof.

Background

The pressure sensor is a basic mechanical sensor widely applied in the fields of industrial production, military equipment, aerospace, navigation and the like. The measuring principle mostly utilizes the Wheatstone bridge principle, the resistance strain effect or the piezoresistance effect, the strain generated by the surface of the elastomer where the bridge arm resistance is positioned under the action of pressure (pressure) is converted into the resistance change of the resistance strain gauge, and then the resistance change is converted into a voltage signal through the Wheatstone bridge.

In some industrial fields, such as petroleum, chemical and metallurgical industries or fields, there is often a requirement for medium-high pressure measurement that works in a high temperature environment (above 200 ℃) for a long time, and in the explosion test and engine test fields of aerospace and military fields, there is usually a requirement for high temperature, medium-high pressure test, and there is a high requirement for frequency response (usually above thousands of hertz). The silicon pressure group type force transducer based on the MEMS technology can meet various limitations when applied to the high-temperature field, such as temperature compensation is needed, a relatively expensive compensation chip is needed when applied to the high-temperature environment, and when applied to the medium-pressure field (from tens of atmospheres to tens of atmospheres), silicone oil is usually needed to adapt to different medium characteristics, but the frequency response can be greatly reduced; high temperature (more than 200 ℃) resistant silicon piezoresistive pressure sensor has very high requirement on raw materials and manufacturing equipment, and is generally unable to measure medium and high pressure, and the warm punching performance is not good, if silicone oil filling encapsulation is adopted, then the high temperature cannot be born again, and the frequency response is difficult to meet the requirement, and the price is high. The patch type pressure sensor has the advantages that as the strain gauge substrate and the patch adhesive are organic matters, the aging is accelerated under the high-temperature environment, the service life is greatly reduced, the service life is very difficult to reach half a year or more in the typical metal smelting and petroleum industries, the performance is obviously reduced under the high-temperature environment, the temperature characteristic consistency of the resistance strain gauge is very difficult to control, and the effective temperature compensation range is narrow by adopting temperature compensation on one hand, and the influence of temperature impact is very large on the other hand; for the medium-high pressure measurement requirement under the high-temperature environment (more than 200 ℃), the patch type pressure sensor is often not long enough in service life, the replacement of the sensor is often caused to stop, the test is stopped and the like, larger loss and even technical bottlenecks are caused, the patch type pressure sensor is often only used for one-time test under more conditions, the temperature compensation range is limited, the temperature impact performance is poor, and the requirements of high precision and multiple use are difficult to meet.

In addition, due to rapid development of computer technology, information technology, artificial intelligence and other technologies, military equipment and some related fields of core industry have higher requirements on distributed pressure measurement, sensors needed in the occasions have strict requirements on high temperature resistance and corrosiveness, the sensors also need to have small volumes and convenient installation, the pressure sensing section is required to be as small as possible, the influence on the pressure sensing surface of a test piece is reduced as much as possible, the silicon piezoresistive sensor has natural advantages in the aspects of miniaturization and batch production, but the patch type pressure sensor is difficult to control the volume once adopting a silicone oil filling technology during medium-high pressure measurement, but the patch type pressure sensor needs to be small, high-level skill personnel are difficult to assemble, the batch production is difficult to realize due to excessively small strain gauges, the resistance is difficult to realize large, the sensor generates heat and has poor thermal stability, and the preheating time and measurement accuracy can influence the actual use effect; more complex, the fields of industry, aerospace, military industry and the like which are continuously emerging are more and more high in comprehensive requirements on the pressure sensor, sometimes even superposition of special requirements in different fields can occur, the requirements on the pressure sensor are multiplied, the pressure sensor belongs to a product with larger consumption, and if the pressure sensor cannot be produced in batches, the technology development is difficult to effectively promote, so that good social benefits are generated.

Therefore, there is a need for a pressure sensor that is resistant to high temperatures, small in size, has a relatively high frequency response, can cover at least a medium pressure range, is excellent in life and reliability, and is easy to mass-produce.

Disclosure of Invention

The invention aims to provide a pressure sensor and a manufacturing method thereof, which are used for solving the problems that the traditional pressure sensor is difficult to meet the measurement requirement of medium and high pressure in a high-temperature environment (more than 200 ℃), and the problem that the traditional pressure sensor is difficult to be small.

In order to achieve the above object, the present invention provides a pressure sensor comprising:

the shell is cylindrical, one end of the shell is open, and the other end of the shell is closed;

The conductive pins are inserted into the other end of the shell in parallel to the axial direction of the shell;

The sensing element is arranged in the shell and comprises a first cylinder and a second cylinder which are sequentially communicated, one end of the first cylinder, which is away from the second cylinder, is closed, and a plurality of resistors and a plurality of bonding pads which are electrically connected with the resistors are arranged on the surface of one end of the first cylinder;

A lead element located within the housing and connected to the first cylinder of the sensing element;

The conductive bent needle is inserted into the lead element, one end of the conductive bent needle is electrically connected with the conductive needle, and the other end of the conductive bent needle is electrically connected with the bonding pad.

Preferably, the sensing element and the shell are both made of martensitic stainless steel or high-temperature alloy, the shell comprises a first cylinder section, a second cylinder section and a third cylinder section which are sequentially communicated, the first cylinder section is in a hexagonal cylinder shape, one end of the first cylinder section is closed and provided with a plurality of pinholes, and each conductive needle penetrates through one pinhole; an external thread is arranged on the outer wall of the second cylinder section, and the outer diameter of the third cylinder section is smaller than that of the second cylinder section;

The second cylinder is inserted into the third cylinder section.

Preferably, the periphery of the first cylinder is provided with a notch, the notch is parallel to the central axis of the first cylinder, the lead element is made of ceramic, austenitic stainless steel or high-temperature alloy and comprises a connecting plate and a compensating plate extending from the connecting plate, and the compensating plate is arranged at the notch and supplements the notch.

Preferably, the sensor further comprises a hoop, wherein the hoop is sleeved on the peripheries of the first cylinder and the patch plate and is in contact with the periphery of the first cylinder of the sensor;

The outer diameter of the first cylinder is smaller than that of the second cylinder, and the outer diameter of the hoop is the same as that of the second cylinder.

Preferably, two resistor pairs are arranged on the one end surface of the first cylinder of the sensitive element, each resistor pair comprises a pair of resistors connected in series, and the resistor pairs are electrically connected with each other to form a wheatstone bridge;

The bonding pad is electrically connected to the leading-out end of the resistor, and the bonding pad is far away from the notch.

Preferably, at least one compensation resistor is further arranged on the one end surface of the first cylinder of the sensing element, and the compensation resistor is electrically connected to the wheatstone bridge for bridge zero point compensation;

The resistor and the compensation resistor are both thin film resistors.

Preferably, the surface of the bonding pad of the sensitive element, the surface of the conductive pin and the surface of the conductive curved pin are all plated with gold layers.

Preferably, an insertion hole is formed in one end of the conductive pin located in the housing, the conductive bent pin includes a vertical portion and a horizontal portion bent from the top end of the vertical portion, the horizontal portion of each conductive bent pin is electrically connected to one of the bonding pads through gold wires, and the other end of the vertical portion of each conductive bent pin is inserted into one of the insertion holes.

Preferably, the sealing device further comprises a sealing piece, wherein the other end of the shell is provided with an air suction hole, the air suction hole is a stepped hole, and the sealing piece is connected in the stepped hole in a sealing way and does not protrude out of the surface of the other end of the shell.

The invention also provides a manufacturing method of the pressure sensor, which comprises the following steps:

Step 1: the first cylinder and the second cylinder of the sensitive element are manufactured, and the resistor, the bonding pad and the embedded connecting wire for electrically connecting the resistor and the bonding pad are formed on the surface of one end of the first cylinder by utilizing a sputtering film process;

Step 2: manufacturing the lead element, the shell, the conductive bent needle and the conductive needle, sintering the conductive bent needle on the lead element by adopting a glass powder sintering process, and sintering the conductive needle on the other end of the shell;

Step 3: connecting the lead element to a first cylinder of the sensitive element, and electrically connecting the bonding pad of the sensitive element and the conductive bent needle by adopting gold wire ball bonding;

Step 4: the conductive curved needle is inserted into the conductive needle to form contact conduction, the shell is sleeved on the sensitive element, and the sensitive element and the shell are welded, fixed and sealed by welding;

Step 5: and placing the pressure sensor in a vacuum environment for a preset time, pumping out the gas between the shell and the sensitive element, sealing the shell, and taking out the pressure sensor from the vacuum environment.

The pressure sensor has the beneficial effects that: the lead element is used for replacing the circuit board to communicate the bonding pad of the sensitive element with an external cable, so that the high temperature resistance of the sensor is greatly improved; the invention effectively solves the contradiction among various harsh requirements of high precision, medium and high pressure, small volume, high frequency response, long service life, high reliability and the like under the environmental pressure measurement requirements of various high temperature or wide temperature areas, and is suitable for various occasions of high pressure measurement in high temperature environments in the fields of industry, aerospace and military industry.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the invention.

FIG. 1 illustrates a first perspective structural schematic of a pressure sensor according to an exemplary embodiment of the present invention;

FIG. 2 illustrates a second perspective structural schematic of a pressure sensor according to an exemplary embodiment of the present invention;

FIG. 3 illustrates a schematic structural diagram of a housing in a pressure sensor according to an exemplary embodiment of the present invention;

FIG. 4 illustrates a first perspective connection schematic of a sensing element, a lead element, and a ferrule in a pressure sensor according to an exemplary embodiment of the present invention;

FIG. 5 illustrates a second perspective connection schematic of a sensing element, a lead element, and a ferrule in a pressure sensor according to an exemplary embodiment of the present invention;

FIG. 6 illustrates a schematic view of the angular connection of the sensing element, lead element in a pressure sensor in accordance with an exemplary embodiment of the present invention;

FIG. 7 illustrates a schematic diagram of the structure of a sensing element in a pressure sensor according to an exemplary embodiment of the present invention;

FIG. 8 illustrates a schematic diagram of a resistive arrangement of a sensing element in a pressure sensor in accordance with an exemplary embodiment of the present invention;

FIG. 9 illustrates a schematic diagram of a Wheatstone bridge in a pressure sensor in accordance with an exemplary embodiment of the invention.

Reference numerals illustrate:

1. A sensor; 101. a first cylinder; 102. a second cylinder; 2. a housing; 201. a first barrel section; 202. a second barrel section; 203. a third barrel section; 3. a lead element; 301. a connecting plate; 302. a circular plate is supplemented; 4. a hoop; 5. conductive curved needles; 6. a conductive needle; 7. gold wires; 8. a bonding pad; 9. cutting the surface; 10. an external thread; 11. sealing sheet, 12, resistance; 13. compensation resistor, 14, pinhole; 15. a plug hole; 16. an air suction hole, 17 and a clamping table.

Detailed Description

Preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention are described below, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

To solve the problems of the prior art, the present invention provides a pressure sensor, as shown in fig. 1 and 9, including:

A shell 2, wherein the shell 2 is in a cylindrical shape with one end open and the other end closed;

a plurality of conductive pins 6, wherein the conductive pins 6 are inserted at the other end of the housing 2 in parallel to the axial direction of the housing 2;

The sensor 1, the sensor 1 locates in the outer cover 2, including first cylinder 101 and second cylinder 102 communicated sequentially, the first cylinder 101 is kept away from one end of the second cylinder 102 and closed, there are multiple resistors 12 and multiple pads 8 electrically connected to resistor 12 on one end surface of the first cylinder 101;

A lead element 3, the lead element 3 being located within the housing 2 and connected to the first cylinder 101 of the sensor 1;

the conductive bent needle 5 is inserted into the lead element 3, one end of the conductive bent needle 5 is electrically connected to the conductive needle 6, and the other end of the conductive bent needle 5 is electrically connected to the bonding pad 8.

According to the pressure sensor, the lead element 3 is used for replacing a circuit board to communicate the bonding pad 8 of the sensing element 1 with an external cable, so that the high temperature resistance of the sensor is greatly improved; the invention effectively solves the contradiction among various harsh requirements of high precision, medium and high pressure, small volume, high frequency response, long service life, high reliability and the like under the environmental pressure measurement requirements of various high temperature or wide temperature areas, and is suitable for various occasions of high pressure measurement in high temperature environments in the fields of industry, aerospace and military industry.

As shown in fig. 1 to 3, the sensing element 1 and the housing 2 are both made of martensitic stainless steel or high-temperature alloy, the housing 2 comprises a first barrel section 201, a second barrel section 202 and a third barrel section 203 which are sequentially communicated, the first barrel section 201 is in a hexagonal barrel shape, one end of the first barrel section 201 is closed and provided with a plurality of pinholes 14, and each conductive needle 6 passes through one pinhole 14; the outer wall of the second barrel section 202 is provided with an external thread 10, and the outer diameter of the third barrel section 203 is smaller than the outer diameter of the second barrel section 202;

The second cylinder 102 is inserted into the third cylinder section 203 with the end face of the second cylinder 102 aligned with the end face of the third cylinder section 203.

The shell 2 is arranged on the sensitive element 1, one end of the second cylinder 102 of the sensitive element 1, which is far away from the first cylinder 101, is in the same plane with the end face of the third cylinder section 203 of the shell 2, which is far away from the first cylinder section 201, so that when the sensor is conveniently arranged and used, an extrusion sealing mode is adopted between the plane and the interface plane of the use occasion.

Preferably, the sensitive element 1 and the shell 2 are connected in a sealing way through welding, such as laser welding, argon arc welding, electron beam welding and other fusion welding methods.

Adopt laser welding to weld sensitive element 1 and shell 2 as an organic wholely, the welding seam both can guarantee structural strength, does not take place relative motion under sensor installation pretightning force and medium pressure effect, can make not have the gap between sensitive element 1 and the shell 2 again, and gas and other foreign matter can not get into inside the sensor from the junction, realizes sealedly.

The sensitive element 1 is made of elastic membrane, when the working temperature is not more than 300 ℃, the sensitive element 1 and the shell 2 are usually made of high-strength corrosion-resistant martensitic stainless steel, and when the temperature is higher, the sensitive element is made of high-temperature alloy, and the sensitive element and the shell can be specifically selected according to the use requirement.

As shown in fig. 1 and 2, the outer wall of the second barrel section 202 of the housing 2 is provided with external threads 10, so that the volume of the sensor can be greatly reduced by reducing the frontal height of the sensor, the cavity in the sensitive element 1 has a larger diameter-depth ratio, and the sensor has higher frequency response; the outer cylindrical surface of the first cylinder section 201 is a hexagonal cylinder, which has six sides, and the corners are rounded, and the outer cylindrical surface of the first cylinder section 201 may also be square or cylindrical. The first barrel section 201, the second barrel section 202, and the third barrel section 203 form an installation space inside, which is stepped. The conductive needle 6 passes through the first barrel section 201 to the inside of the housing 2 and is disposed axially parallel to the housing 2.

The first cylinder 101 and the second cylinder 102 are spliced into a cylindrical cavity, and when in use, the first cylinder 101 of the sensing element 1 is arranged in the shell 2, and the pressure to be detected acts on the inner side surface of the first cylinder 101.

As shown in fig. 7, the outer periphery of the first cylinder 101 is provided with a notch 9, the notch 9 is not communicated with the cylindrical cavity, the notch 9 is parallel to the central axis of the first cylinder 101, the notch 9 makes the first cylinder 101 form a cutting surface, and the cutting surface is parallel to the axial direction of the first cylinder 101; the lead element 3 is made of ceramic, austenitic stainless steel or high-temperature alloy, and comprises a connecting plate 301 and a patch plate 302 extending from the connecting plate 301, wherein the patch plate 302 is arranged at the notch 9, and the notch 9 is supplemented.

Preferably, the lead element 3 is made of ceramic, and can be applied to a temperature environment exceeding 200 ℃.

In other embodiments of the application, the lead element 3 may also be made of austenitic stainless steel or superalloy to be suitable for use in a temperature environment of around 200 ℃ where it is more economical to use austenitic stainless steel or superalloy than to use ceramic.

As shown in fig. 5 and 6, the connection plate 301 of the lead element 3 is formed by cutting a cylinder parallel to the axial direction thereof, the connection plate 301 can be a round large cutting circle, a round small cutting circle or a semicircle, and the round plate is cut into a part along the thickness direction, so that the operation of avoiding welding the wire bent needle 5 and the bonding pad 8 is facilitated; the patch plate 302 is also formed by cutting a cylindrical body parallel to the axial direction thereof, the patch plate 302 is a small circular cut, and after the patch plate 302 is clamped at the notch 9, a full circle is formed with the outer periphery of the first cylinder 101.

As shown in fig. 4 and 5, the pressure sensor further includes a hoop 4, where the hoop 4 is sleeved on the outer circumferences of the first cylinder 101 and the patch plate 302, and contacts with the outer circumference of the first cylinder 101 of the sensing element 1, so as to fasten the patch plate 302 with the first cylinder 101;

The outer diameter of the first cylinder 101 is smaller than the outer diameter of the second cylinder 102, and the outer diameter of the hoop 4 is the same as the outer diameter of the second cylinder 102.

The hoop 4 is of a circular ring structure, the outer diameter of the first cylinder 101 is smaller than the outer diameter of the second cylinder 102 to form a step, the clamping table 17 is arranged on the inner wall of the shell 2, one end of the hoop 4 is clamped on the step, the other end of the hoop is clamped on the clamping table 17, the hoop 4 axially compresses the first cylinder 101 and the lead element 3, and the sensitive element 1 and the lead element 3 are firmly fixed under the influence of mechanical environment such as vibration, impact, acceleration and thermal expansion and contraction of a thermal environment, and the lead element 3 is used for fixing the conductive curved needle 5.

As a preferable scheme, the hoop 4 and the outer wall of the sensitive element 1 can be welded together by adopting a welding mode such as laser welding, so that the internal structure of the sensor is firmer.

Two resistor pairs are arranged on one end surface of the first cylinder 101 of the sensing element 1, each resistor pair comprises a pair of resistors 12 connected in series, and the resistor pairs are electrically connected with each other to form a Wheatstone bridge;

The pad 8 is electrically connected to the lead-out terminal of the resistor 12, and the pad 8 is disposed away from the notch 9.

In one embodiment of the application, as shown in fig. 8, the two resistor pairs are symmetrically distributed.

In other embodiments of the application, the two pairs of resistors are axisymmetrically distributed along the diameter of the first cylinder 101, and the diameter is parallel to the notch 9 of the first cylinder 101, the symmetry axis is perpendicular to the diameter of the two pairs of resistors, and each side of the symmetry axis has two pairs of resistors 12.

The stress surface of the pressure sensor, that is, the inner surface of one end of the first cylinder 101 is uniformly stressed, so that the arrangement mode of the resistor pair may not be symmetrical or not limited, and the arrangement mode is specific to the actual situation.

The first cylinder 101 of the sensor 1 is also provided with at least one compensation resistor 13 on one end surface, and the compensation resistor 13 is electrically connected to the wheatstone bridge for bridge zero point compensation;

the resistor 12 and the compensation resistor 13 are both thin film resistors.

As shown in fig. 9, the wheatstone bridge has four endpoints, wherein endpoint a (a) and endpoint d are respectively a power supply positive electrode and a power supply negative electrode, endpoint c and endpoint d are respectively a power supply positive electrode and a power supply negative electrode, endpoint a (a) is an open endpoint, two connection points are provided, two leading-out ends of the compensation resistor 13 are respectively connected to the two connection points, and the serial connection position of the compensation resistor 13 is adjusted according to the actual situation and the test result, so that the endpoint a is used as an output positive electrode or the endpoint a is used as an output negative electrode, and the potential difference between the output positive electrode and the output negative electrode is close to 0.

As shown in fig. 3, an insertion hole 15 is provided at one end of the conductive pin 6 located in the housing 2, the conductive bent pin 5 includes a vertical portion and a horizontal portion bent by one end of the vertical portion, the horizontal portion of each conductive bent pin 5 is electrically connected to a bonding pad 8 through a gold wire 7, and the other end of the vertical portion of each conductive bent pin 5 is inserted into one insertion hole 15.

The conductive bent needle 5 and the conductive needle 6 can be made of high-temperature alloy, and gold plating is performed after sintering and fixing. The gold wire 7 is a standard product commonly used in the market.

The vertical part of the conductive curved needle 5 coincides with the axis of the plug hole 15 and is in shaft hole fit, the vertical part of the conductive curved needle 5 is parallel to the axial direction of the first cylinder 101, and the horizontal part is perpendicular to the axial direction of the first cylinder 101.

When the shell 2 is installed, the plug holes 15 of the conductive pins 6 of the shell 2 are sleeved on the conductive bent pins 5 of the lead element 3, so that the conductive performance is ensured on one hand due to firm extrusion contact, and the stability of the lead element 3 is improved on the other hand, so that the lead element 3 is more easily resistant to the influence of mechanical environment and thermal environment.

As a preferred solution, the entrance of the plugging hole 15 may be configured as a bell mouth structure, so that the assembly is easy when the axis of the vertical portion of the conductive bent needle 5 and the axis of the plugging hole 15 are not completely vertical due to the accumulation of machining and assembly errors.

As an alternative, the diameter of the insertion hole 15 may be greater than the diameter of the vertical portion of the conductive curved needle 5, and meanwhile, a plurality of spring pieces are arranged in the insertion hole 15 and arch towards the axis in the hole and around the circumference of the inner hole, so that when the conductive curved needle 5 is inserted into the insertion hole 15, the spring pieces are pressed on the periphery of the conductive curved needle 5 along the circumference of the conductive curved needle 5 due to elastic force, and good electrical contact is achieved.

The surface of the bonding pad 8 of the sensor 1, the surface of the conductive pin 6 and the surface of the conductive bent pin 5 are all plated with gold layers. The bonding pad 8, the conductive pin 6 and the conductive bent pin 5 are plated with gold and connected by adopting the gold wire 7, so that the corrosion of the environment atmosphere can be prevented, and the service life and the reliability can be improved. The bonding pad 8 and the conductive bent needle 5 and the gold wire 7 are fixed by gold wire ball bonding. The gold wire ball welding process is mature and efficient, is suitable for batch production, and is convenient for batch production of the sensors.

In other embodiments of the present application, the sensing element 1 and the conductive bent needle 5 may be soldered by a high Wen Shougong soldering method which is convenient for small-scale production; and a high-melting-point brazing material is adopted, and a high-temperature soldering iron, a flame welding gun or a hot oven and other devices are used for realizing the welding of the lead wire, the bonding pad 8 of the sensitive element 1 and the conductive bent needle 5, so that the conduction between the bonding pad 8 of the sensitive element 1 and the conductive bent needle 5 is realized.

In one embodiment of the present application, the pads 8 are five and arc-shaped and are located below the cut portions of the connection plate 301 for processing.

Four conductive bent pins 5 are arranged, each conductive bent pin 5 is electrically connected with one bonding pad 8 through a gold wire 7, a part of bonding pads 8 on the sensitive element 1 are connected with the conductive bent pins 5 on the lead element 3 through the gold wire 7, the plug holes 15 of the conductive pins 6 of the shell 2 are sleeved on the vertical parts of the conductive bent pins 5 on the lead element 3, the resistors 12 on the sensitive element 1 form a Wheatstone bridge, zero signals are output outwards through the exposed conductive pins 6 on the shell 2, and when a medium fills the cavity in the sensitive element 1 and acts on the inner surface of the first cylinder 101 of the sensitive element 1, the sensor outputs signals proportional to pressure.

In one embodiment of the present application, a three-proof protection layer may be coated on the surface of the sensing element 1, specifically, the three-proof protection layer is disposed on one end surface of the first cylinder 101, for preventing water, dust and static electricity to the resistor 12 and the bonding pad 8. Under severe environment, such as damp heat, frosting pollution and the like, the sensor is possibly damaged, so that the surface of the elastic membrane of the sensitive element 1 is subjected to three-proofing treatment, so that the high-precision measurement can be stably realized for a long time under the severe environment, and the material of the three-proofing protective layer can be selected according to the working temperature and the specific environment, such as organic silicon three-proofing paint or polyurethane three-proofing paint and the like. The material of the three-protection layer is suitable for working temperature when being selected, so that the capability of the surface of the sensitive element for resisting the corrosion of the environmental atmosphere is improved.

In other embodiments of the present application, the inside of the housing 2 may be vacuumized to place the sensing element 1 in a vacuum environment, in which case a three-protection layer may not be provided on the surface of the sensing element 1.

The pressure sensor further comprises a sealing piece 11, the other end of the shell 2 is provided with an air suction hole 16, the air suction hole 16 is a stepped hole and comprises a large-diameter section and a small-diameter section, the large-diameter section is close to the surface of the other end of the shell 2, and the sealing piece 11 is connected in the stepped hole in a sealing way and does not protrude out of the surface of the other end of the shell 2. The sealing piece 11 is connected with the shell 2 by welding.

The sealing piece 11 is connected in the large-diameter section of the stepped hole, is matched with the shaft hole of the air suction hole 16, the exposed end of the sealing piece 11 is flush with the outer surface of the shell 2, the stepped hole can enable gas inside the sensor to be discharged rapidly in a vacuum environment, and the stepped hole can serve as a bearing table of the sealing piece 11, so that the sealing piece 11 cannot fall into the sensor, and the shell 2 is flush with the outer surface of the sealing piece 11, so that welding is convenient to implement.

In one embodiment of the application, the sealing piece 11 and the shell 2 are welded by vacuum electron beam welding, the sensor is firstly required to be placed in a vacuum box of the electron beam welding, the evacuation process can simultaneously realize the gas discharge in the sensor, the sealing piece 11 and the shell 2 are welded and fixed by using an electron beam, the welding seam has the sealing function, and the sensor is taken out from the vacuum box to form a vacuum environment in the sensor.

In other embodiments of the present application, after the sensor is placed in a vacuum box and the internal gas is exhausted, vacuum grease is coated on the contact surface of the sealing sheet 11 and the housing 2, or a sealing gasket is provided, a certain pressure is applied to the sealing sheet 11 by using a tool, the sensor is taken out from the vacuum box, and then the sealing sheet 11 and the housing 2 are fixedly sealed by using laser welding.

The vacuum state is kept in the sensor through the air suction hole 16, so that the internal materials of the sensor are not corroded by various environmental gas components, and the sensor indication value is not drifted along with the temperature or the measurement accuracy is not reduced due to the influence of the temperature of the internal gas state.

When the pressure sensor is used, the sensor is arranged on a using end opening through the external thread 10 on the shell 2, and can be sealed by adopting a raw material belt or a sealing gasket according to the shape of the using end opening, wherein the common raw material belt or polytetrafluoroethylene sealing gasket is generally used below 300 ℃, and a metal sealing gasket is used at a higher temperature or is directly welded on a pressure measuring pipeline. The electrical part is connected with a bare conductive needle 6 on the shell 2 by a crimping contact pin with holes, the other end is connected with a testing instrument by a crimping lead, an electric signal is output, and when a medium is led into a cavity of the sensitive element 1 to form pressure, and the upper surface of the sensitive element 1 is deformed, the sensor outputs the electric signal which is approximately in linear relation with the applied pressure.

According to the sensor, the external threads 10 are arranged on the shell 2, the volume of the sensor is greatly reduced, the sensitive element 1 and the lead element 3 are connected through the gold thread 7 for gold wire ball welding, the use of common tin solder is avoided, the bonding pad 8 of the sensitive element 1 is protected by gold plating, the lead element 3 and the conductive bent needle 5 and the conductive needle 6 of the shell 2 are fixed in corresponding holes through a glass powder sintering method, the fixed strength can be ensured, the high temperature resistance and the tightness are high, the surfaces of the conductive bent needle 5 and the conductive needle 6 are plated with gold, the lead wire and the lead wire welding point can withstand the high temperature far exceeding 200 ℃, the chemical and physical conductivity can be kept stable, the shell 2 and the sensitive element 1 are fixed and sealed by using laser welding, the shell 2 and the sealing piece 11 are fixed and sealed by adopting electron beam welding in a vacuum environment, the inside of the sensor is kept in a vacuum state for a long time, the sensitive element 1 and each electrical connection point are prevented from being corroded slowly by various environmental gas components, the pressure electronic drift or the precision drop caused by the change of the internal sealing gas state due to the environmental temperature is prevented, meanwhile, the high pressure electronic drift or the precision drop can be ensured, the high pressure electronic drift can be ensured, the high pressure resistance and the high precision can be better than the high-precision performance can be realized when the pressure sensor is required to be compared with the stress sensor 1 and the high-frequency resistance performance test performance is tested under the high-quality condition, and high performance test condition, and high performance can meet the requirements, and high performance test performance can be test performance, and has good performance can have the performance test performance and has high performance test performance; the invention effectively solves the contradiction among various harsh requirements of high precision, medium and high pressure, small volume, high frequency response, long service life, high reliability and the like under the environmental pressure measurement requirements of various high temperature or wide temperature areas, and is suitable for various occasions of high pressure measurement in high temperature environments in the fields of industry, aerospace and military industry.

step 1: a first cylinder 101 and a second cylinder 102 of the sensor 1 are manufactured, and a resistor 12, a bonding pad 8 and an embedded connecting wire for electrically connecting the resistor 12 and the bonding pad 8 are formed on one end surface of the first cylinder 101 by utilizing a sputtering film process;

step 2: manufacturing a lead element 3, a shell 2, a conductive bent needle 5 and a conductive needle 6, sintering the conductive bent needle 5 on the lead element 3 by adopting a glass powder sintering process, and sintering the conductive needle 6 on the other end of the shell 2;

Step 3: connecting the lead element 3 to the first cylinder 101 of the sensing element 1, and electrically connecting the bonding pad 8 of the sensing element 1 and the conductive bent needle 5 by adopting gold wire ball bonding;

Step 4: the conductive bent needle 5 is inserted into the conductive needle 6 to form contact conduction, the shell 2 is sleeved on the sensitive element 1, and the sensitive element 1 and the shell 2 are welded, fixed and sealed;

Step 5: after the pressure sensor is placed in a vacuum environment for a preset time and the gas between the housing 2 and the sensor 1 is extracted, the housing 2 is sealed and the pressure sensor is taken out from the vacuum environment.

The step 1 adopts a sputtering film process to manufacture the sensitive element 1, so that miniaturization is easier to realize, the using temperature range is wide, the wide temperature region work and the low temperature drift characteristic are ensured, the temperature performance of the full temperature region is quite excellent when uncompensated, for example, the zero drift value of the full temperature region is mostly within 3 percent FS/or even within 2 percent FS, and the temperature can be further improved through temperature compensation; the normal temperature precision of the sensor can reach within 0.2% FS or even 0.1% FS; the diameter of the sensor can be up to 10mm or less, the threads of the shell can be up to M10X1 or less, and the total height of the sensor can be up to 20mm or less; the diameter-depth ratio of the cavity of the sensitive element can reach about 1, the natural frequency of the pressure sensing surface of the sensitive element of the sensor can reach more than tens of kHz, and the effective frequency response of the sensor can reach several kHz or even more than tens of kHz.

In step 2, each conductive pin 5 is sintered in a corresponding hole on the lead element 3 by a glass frit sintering process, and each conductive pin 6 is sintered in a corresponding pin hole 14 on the housing 2 for fixing.

In the step 3, the hoop 4 is sleeved outside the first cylinder 101 of the sensing element 1, the patch plate 302 of the lead element 3 is inserted into the gap between the first cylinder 101 and the hoop 4, and the notch 9 is patch; first, a first point is welded on the terminal pad 8 of the bridge of the sensor 1 by gold wire ball bonding, and then a second point is welded on the end of the conductive bent needle 5 of the lead element 3.

In step 4, the shell 2 is installed, the conductive pins 6 are sleeved on the conductive bent pins 5 on the lead element 3 one by one to form contact conduction, meanwhile, the shell 2 is sleeved on the sensitive element 1, and the sensitive element 1 and the shell 2 are welded, fixed and sealed in a welding mode such as laser welding.

In step 5, after the gas between the shell 2 and the sensitive element 1 is pumped out, a sealing piece 11 is arranged at a pumping hole 16 on the shell 2, the shell 2 and the sealing piece 4 are welded and fixed and sealed by adopting vacuum electron beam welding, and the sensor is taken out from a vacuum environment for integral debugging and test.

In other embodiments of the present application, when the pressure sensor is not vacuumized, three-proofing protection may be performed on one end surface of the first cylinder 101 of the sensing element 1, that is, the surface of the bonding pad 8 of the sensing element 1 is uniformly coated with the three-proofing protection layer and cured, so as to protect the bonding pad 8 and the resistor 12.

The method for manufacturing the pressure sensor adopts mature, convenient and easy technology, and is very suitable for mass production in a mechanized and pipeline mode.

All the processing and manufacturing methods adopted by the whole sensor are mature and easy, and the sputtering film technology for processing and manufacturing the sensitive element 1 is quite suitable for mass production in a mechanized and streamline mode. The other parts can be realized through the traditional machining process, sintering process, integrated circuit packaging, welding, assembly process and the like, the relative bottlenecks are manual assembly, debugging and inspection test, and the problems of manual welding, assembly, debugging and inspection test can be solved through the electric tool, the special tool and the welding equipment which are widely used in the mature common sensor production line. The whole scheme can be divided in the process according to the process of the mature sensor production flow, and a proper number of assembly tools and calibration and test inspection tools are configured according to the required scale to realize batch production.

The foregoing description of embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described.

Claims

1. A pressure sensor, comprising:

a shell (2), wherein the shell (2) is in a cylindrical shape with one end open and the other end closed;

A plurality of conductive pins (6), wherein the conductive pins (6) are inserted into the other end of the housing (2) in parallel to the axial direction of the housing (2);

The sensor (1) is arranged in the shell (2) and comprises a first cylinder (101) and a second cylinder (102) which are sequentially communicated, one end of the first cylinder (101) deviating from the second cylinder (102) is closed, and a plurality of resistors (12) and a plurality of bonding pads (8) electrically connected with the resistors (12) are arranged on the surface of one end of the first cylinder (101);

-a lead element (3), said lead element (3) being located within said housing (2) and connected to said first cylinder (101) of said sensor element (1);

The conductive bent needle (5) is inserted into the lead element (3), one end of the conductive bent needle (5) is electrically connected with the conductive needle (6), and the other end of the conductive bent needle (5) is electrically connected with the bonding pad (8);

The sensing element (1) and the shell (2) are both made of martensitic stainless steel or high-temperature alloy, the shell (2) comprises a first cylinder section (201), a second cylinder section (202) and a third cylinder section (203) which are sequentially communicated, the first cylinder section (201) is in a hexagonal cylinder shape, one end of the first cylinder section (201) is sealed and provided with a plurality of pinholes (14), and each conductive needle (6) penetrates through one pinhole (14); an external thread (10) is arranged on the outer wall of the second barrel section (202), and the outer diameter of the third barrel section (203) is smaller than the outer diameter of the second barrel section (202);

the second cylinder (102) is inserted into the third cylinder section (203);

The periphery of the first cylinder (101) is provided with a notch (9), the notch (9) is parallel to the central axis of the first cylinder (101), the lead element (3) is made of ceramic, austenitic stainless steel or high-temperature alloy and comprises a connecting plate (301) and a compensating plate (302) extending out of the connecting plate (301), and the compensating plate (302) is arranged at the notch (9) and supplements the notch (9);

The sensor further comprises a hoop (4), wherein the hoop (4) is sleeved on the peripheries of the first cylinder (101) and the compensating plate (302) and is contacted with the periphery of the first cylinder (101) of the sensor (1);

the outer diameter of the first cylinder (101) is smaller than the outer diameter of the second cylinder (102), and the outer diameter of the hoop (4) is the same as the outer diameter of the second cylinder (102);

-said one end surface of said first cylinder (101) of said sensor (1) is provided with two pairs of resistors, each comprising a pair of said resistors (12) connected in series, said pairs of resistors being electrically connected to each other to form a wheatstone bridge;

The bonding pad (8) is electrically connected to the leading-out end of the resistor (12), and the bonding pad (8) is far away from the notch (9).

2. Pressure sensor according to claim 1, characterized in that said one end surface of said first cylinder (101) of said sensor element (1) is further provided with at least one compensation resistor (13), said compensation resistor (13) being electrically connected to said wheatstone bridge for bridge zero compensation;

the resistor (12) and the compensation resistor (13) are both thin film resistors.

3. Pressure sensor according to claim 1, characterized in that the surface of the bonding pad (8) of the sensor element (1), the surface of the conductive pin (6) and the surface of the conductive bent pin (5) are all plated with a gold layer.

4. Pressure sensor according to claim 1, characterized in that the end of the conductive pin (6) located in the housing (2) is provided with a plug hole (15), the conductive bent pin (5) comprises a vertical portion and a horizontal portion bent by one end of the vertical portion, the horizontal portion of each conductive bent pin (5) is electrically connected to one of the bonding pads (8) by a gold wire (7), and the other end of the vertical portion of each conductive bent pin (5) is plugged into one of the plug holes (15).

5. The pressure sensor according to claim 1, further comprising a sealing sheet (11), wherein the other end of the housing (2) is provided with an air extraction hole (16), the air extraction hole (16) is a stepped hole, and the sealing sheet (11) is sealingly connected in the stepped hole and does not protrude from the surface of the other end of the housing (2).

6. A method of manufacturing a pressure sensor according to any one of claims 1 to 5, comprising:

Step 1: -making the first cylinder (101) and the second cylinder (102) of the sensor (1), forming the resistor (12), the bonding pad (8) and buried connection lines for electrically connecting the resistor (12) and the bonding pad (8) on the one end surface of the first cylinder (101) by means of a sputtering film process;

Step 2: manufacturing the lead element (3), the shell (2), the conductive bent needle (5) and the conductive needle (6), sintering the conductive bent needle (5) on the lead element (3) by adopting a glass powder sintering process, and sintering the conductive needle (6) on the other end of the shell (2);

step 3: connecting the lead element (3) to a first cylinder (101) of the sensitive element (1), and electrically connecting the bonding pad (8) of the sensitive element (1) and the conductive bent needle (5) by adopting gold wire ball bonding;

Step 4: the conductive curved needle (5) is inserted into the conductive needle (6) to form contact conduction, the shell (2) is sleeved on the sensitive element (1), and the sensitive element (1) and the shell (2) are welded, fixed and sealed by welding;

Step 5: and placing the pressure sensor in a vacuum environment for a preset time, pumping out the gas between the shell (2) and the sensitive element (1), sealing the shell (2), and taking out the pressure sensor from the vacuum environment.