Preparation method of temperature and pressure integrated sensor and temperature and pressure integrated sensor

Abstract

The invention provides a preparation method of a temperature and pressure integrated sensor and the temperature and pressure integrated sensor, and the method comprises the steps: providing a temperature sensing module and a pressure sensing module which are respectively used for measuring a temperature signal and a pressure signal; a stainless steel sheath is provided, the stainless steel sheath at least comprises a first-stage sheath and a second-stage sheath which are sequentially connected in the axial direction, the thickness of the stainless steel sheath is controlled so that the thickness of the first-stage sheath can be smaller than that of the second-stage sheath, a metal coating is arranged on the outer side wall of the first-stage sheath, and no metal coating is arranged on the outer side wall of the second-stage sheath; heat-conducting silicone grease is injected into the first-stage sheath, and pouring sealant is injected into the second-stage sheath. The thickness of the first-stage sheath is reduced, and the outer side wall of the first-stage sheath is provided with the high-heat-conduction metal coating, so that the heat capacity and the heat resistance are reduced, the thermal response time is shortened, and the heat conduction efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and more specifically, to a method for fabricating a temperature and pressure integrated sensor and the temperature and pressure integrated sensor itself. Background Technology

[0002] Currently, integrated temperature and pressure sensors, as key components for simultaneously monitoring temperature and pressure parameters, are widely used in new energy vehicle battery thermal management systems, motor cooling systems, energy storage converters, and battery packs. In these applications, the ability to quickly and accurately acquire temperature and pressure information is crucial for system status monitoring, thermal runaway early warning, and energy efficiency optimization. Summary of the Invention

[0003] In view of this, this application provides a method for fabricating a temperature and pressure integrated sensor and the temperature and pressure integrated sensor, aiming to solve the technical problems of slow thermal response speed and insufficient reliability of the temperature and pressure integrated sensor in the prior art.

[0004] The technical solution provided in this application is as follows: In a first aspect, this application provides a method for fabricating an integrated temperature and pressure sensor, comprising the following steps: Step S11: Provide a temperature sensing module and a pressure sensing module, wherein the temperature sensing module and the pressure sensing module are used to measure temperature signals and pressure signals, respectively; Step S12: Provide a stainless steel sheath, the stainless steel sheath comprising at least a first-level sheath and a second-level sheath connected sequentially along the axial direction, controlling the thickness of the stainless steel sheath such that the thickness of the first-level sheath is less than the thickness of the second-level sheath, wherein the outer wall of the first-level sheath is provided with a metal plating layer, and the outer wall of the second-level sheath is not provided with the metal plating layer. Step S13: Inject thermally conductive silicone grease into the first-stage sheath and inject potting compound into the second-stage sheath.

[0005] Furthermore, in step S13: the area where thermally conductive silicone grease is injected into the first-level sheath coincides with the area covered by the metal plating.

[0006] Furthermore, the sum of the thickness of the first-level sheath and the thickness of the metal plating layer is equal to the thickness of the second-level sheath.

[0007] Furthermore, the ratio of the thickness of the metal plating layer to the thickness of the first-level sheath is between 1:75 and 1:40.

[0008] Furthermore, the metal plating layer includes a nickel plating layer and a gold plating layer, and the ratio of the thickness of the nickel plating layer to the thickness of the gold plating layer is between 3:5 and 5:1.

[0009] Furthermore, the preparation of the metal coating in step S12 includes the following steps: Step S101: Perform a pretreatment on the stainless steel sheath, wherein the temperature of the pretreatment is 50~80℃ and the time of the pretreatment is 30s~5mins; Step S102: Pre-plat the nickel layer on the outer wall of the first-stage sheath after pretreatment, wherein the thickness of the nickel layer is 3~10 micrometers, and the pre-plating current density is 1~5A / dm. 2 ; Step S103: Using electroplating or chemical plating processes, deposit the gold plating layer on the outer wall of the first-level sheath 100 to form the metal plating layer.

[0010] Furthermore, using an electroplating process, a gold plating layer is deposited on the outer wall of the first-level sheath to form the metal plating layer, wherein the electroplating temperature is 20~60℃ and the current density is 0.5~3A / dm³. 2 The pH value is 4~6; or, The gold plating layer is deposited on the outer wall of the first-level sheath using a chemical plating process to form the metal plating layer, wherein the temperature of the chemical plating is 60~90℃.

[0011] Furthermore, after step S13, the following is also included: Step S14: Provide an adapter, the adapter having a boss at one end facing the temperature sensing module, the outer diameter of the boss being smaller than the inner diameter of the second-level sheath, and the second-level sheath being fitted onto the boss.

[0012] Furthermore, after step S14, the following is also included: Step S15: Provide a sealing ring, which is fitted onto the outer wall of the connection between the second-stage sheath and the boss.

[0013] On the other hand, this application also provides a thermo-pressure integrated sensor, which is fabricated using a method for fabricating a thermo-pressure integrated sensor, including: Temperature sensing module, used to measure temperature signals; Pressure sensing module, used to measure pressure signals; A stainless steel sheath, comprising at least a first-stage sheath and a second-stage sheath connected sequentially along the axial direction, wherein the thickness of the first-stage sheath is less than the thickness of the second-stage sheath, and the outer wall of the first-stage sheath is provided with a metal plating layer.

[0014] The solution provided in this application has the following beneficial effects: 1. The fabrication method of the integrated temperature and pressure sensor provided in this application, compared with the prior art, only reduces the thickness of the first-stage sheath and sets a highly thermally conductive metal coating only on the outer wall of the first-stage sheath. The first-stage sheath is the part that is in direct and continuous contact with the external measured medium and is also the core area where heat exchange occurs. Thinning it and setting a metal coating can reduce heat capacity and thermal resistance, reduce thermal response time, and improve thermal efficiency, thereby realizing rapid and accurate temperature measurement of the integrated temperature and pressure sensor. Furthermore, the metal coating has good anti-corrosion and anti-ion migration properties, and can resist external moisture and corrosion. The corrosion of corrosive fluids improves the reliability and extends the lifespan of the integrated temperature and pressure sensor. Using an expensive metal plating only in the first-stage sheath reduces costs while maintaining the sensor's thermal response speed. Furthermore, the thicker second-stage sheath provides sufficient support to ensure the sensor's stability during installation or vibration, preventing deformation or damage. Moreover, filling the first-stage sheath only with thermally conductive adhesive and the second-stage sheath with potting compound further enhances the thermal response speed of the first-stage sheath and improves the sensor's overall performance.

[0015] 2. The method for fabricating the integrated temperature and pressure sensor provided in this application sets the metal plating layer as a composite plating structure of nickel plating and gold plating. The nickel plating layer provides good adhesion to the gold plating layer, ensuring that the gold plating layer will not peel off during subsequent use. In addition, the nickel plating layer can also provide a barrier to the gold plating layer, preventing the metal atoms of the first-stage sheath from diffusing into the gold plating layer under high temperature or long-term use, further preventing the gold plating layer from being contaminated and failing. By setting the ratio of the thickness of the nickel plating layer to the thickness of the gold plating layer to be between 3:5 and 5:1, the thermal response speed of the integrated temperature and pressure sensor can be improved while reducing costs and improving the reliability and lifespan of the integrated temperature and pressure sensor.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the fabrication method of the integrated temperature and pressure sensor provided in this application embodiment; Figure 2 This is a schematic diagram of the stainless steel sheath of the integrated temperature and pressure sensor provided in the embodiments of this application; Figure 3 This is a schematic diagram of the integrated temperature and pressure sensor provided in an embodiment of this application.

[0019] Explanation of reference numerals in the attached figures: 100 - First-level sheath; 200 - Second-level sheath; 300 - Stainless steel sheath. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this application, it should be noted that the terms "inner," "outer," "upper," "lower," "vertical," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, features in the following embodiments can be combined with each other.

[0025] In view of the shortcomings of the prior art, the technical solution of this application is proposed. The technical solution of this application will be described in detail below.

[0026] Please see Figures 1-3 , Figure 1 A flowchart illustrating the fabrication method of the integrated temperature and pressure sensor provided in this application embodiment; Figure 2 This is a schematic diagram of the stainless steel sheath of the integrated temperature and pressure sensor provided in the embodiments of this application; Figure 3 This is a schematic diagram of the integrated temperature and pressure sensor provided in an embodiment of this application. The fabrication method of this integrated temperature and pressure sensor includes the following steps: Step S11: Provide a temperature sensing module and a pressure sensing module, which are used to measure temperature signals and pressure signals, respectively. The temperature sensing module includes a temperature-sensing element and lead terminals. The temperature-sensing element is used to collect temperature change values ​​and can use a negative temperature coefficient thermistor or other suitable thermistors; this application does not limit this. The lead terminals are electrically connected to the temperature-sensing element, and the two are fixedly connected by welding. After welding, the solder joints are insulated and encapsulated with epoxy resin to ensure no air bubbles or short circuit risks. The pressure sensing module includes a pressure-sensitive chip, a pressure interface, and a signal processing circuit. The pressure-sensitive chip can use a piezoresistive or capacitive pressure-sensing element, which is connected to the pressure interface through glass micro-fusion or silicon-silicon bonding processes. The pressure interface has an external thread or flange structure for communication with the measured medium. The output signal of the pressure sensing module is amplified and digitized by the signal processing circuit to output an electrical signal.

[0027] Step S12: Provide a stainless steel sheath 300, which includes at least a first-stage sheath 100 and a second-stage sheath 200 connected sequentially along the axial direction. The thickness of the stainless steel sheath 300 is controlled such that the thickness of the first-stage sheath 100 is less than the thickness of the second-stage sheath 200. The outer wall of the first-stage sheath 100 is provided with a metal plating layer, while the outer wall of the second-stage sheath 200 is not provided with the metal plating layer. The stainless steel sheath 300 is generally a stepped, slender cylinder, divided along the axial direction into at least a first-stage sheath 100 and a second-stage sheath 200 connected sequentially. The shape of the first-stage sheath 100 matches the shape of the temperature sensing element and covers the temperature sensing element; the second-stage sheath 200 covers the lead terminal. The first-stage sheath 100 and the second-stage sheath 200 are connected by an integral molding process, and the connection point has a smoothly transitioning stepped structure to avoid stress concentration and breakage. The thickness of the first-stage sheath 100 is less than the thickness of the second-stage sheath 200. The wall thickness of the first-stage sheath 100 is controlled between 0.14 and 0.20 mm, preferably 0.17 mm, and the wall thickness of the second-stage sheath 200 is controlled between 0.15 and 0.21 mm, preferably 0.18 mm. The thicknesses of the first-stage sheath 100 and the second-stage sheath 200 are achieved through CNC turning, cold heading, or precision tube diameter reduction processes. The outer wall of the first-stage sheath 100 is provided with a metal plating layer, which includes a nickel plating layer in close contact with the outer wall of the first-stage sheath 100 and a gold plating layer in close contact with the nickel plating layer. The nickel plating layer is achieved by electroplating, and the gold plating layer can be formed by electroplating or chemical plating.

[0028] Step S13: Inject thermally conductive silicone grease into the first-level sheath 100 and inject potting compound into the second-level sheath 200. Furthermore, in step S13, the area in the first-level sheath 100 where the thermally conductive silicone grease is injected coincides with the area covered by the metal plating. The first-stage sheath 100 is filled with high thermal conductivity silicone grease, preferably an organosilicon-based paste. To further improve thermal conductivity, fillers such as boron nitride, alumina, or silicon carbide can be added to the silicone grease. The thermal conductivity silicone grease can be injected into the first-stage sheath 100 using precision dispensing or vacuum pressure injection. The temperature sensing element inside the first-stage sheath 100 is fully covered by the thermal conductivity silicone grease without leaving any gaps. The second-stage sheath 200 is filled with epoxy resin and covers the lead terminals. After the thermal conductivity silicone grease is injected and stabilized, the potting compound is injected. During the injection, the uniformly mixed potting compound is slowly injected along the inner wall of the second-stage sheath 200. The fluidity of the potting compound allows it to naturally penetrate and fill the gaps. Alternatively, a vacuum potting process can be used, utilizing the pressure difference to more thoroughly remove internal air bubbles from the potting compound.

[0029] In this embodiment, only the thickness of the first-stage sheath 100 is reduced, and the highly thermally conductive metal coating is only provided on the outer wall of the first-stage sheath 100. The first-stage sheath 100 is the part that is in direct and continuous contact with the external measured medium and is also the core area where heat exchange occurs. Reducing its thickness and providing the metal coating can reduce heat capacity and thermal resistance, shorten the thermal response time, and improve the thermal efficiency, thereby enabling the temperature and pressure integrated sensor to measure temperature quickly and accurately. Furthermore, the metal coating has good anti-corrosion and anti-ion migration properties, which can resist the erosion of external water vapor and corrosive fluids, improving the temperature and pressure integrated sensor. This improves the reliability and extends the lifespan of the device. The expensive metal plating on only the first-stage sheath 100 reduces costs while maintaining the thermal response speed of the integrated temperature and pressure sensor. Furthermore, the thicker second-stage sheath 200 provides sufficient support strength to ensure the stability of the integrated temperature and pressure sensor in installation or vibration environments, preventing deformation or damage. Moreover, filling the first-stage sheath 100 with thermally conductive adhesive and the second-stage sheath 200 with potting compound further enhances the thermal response speed of the first-stage sheath 100 and improves the performance of the integrated temperature and pressure sensor.

[0030] Furthermore, by injecting high thermal conductivity silicone grease inside the first-stage sheath 100, thermal resistance can be further reduced, improving the response speed of the integrated temperature and pressure sensor. By injecting potting compound inside the second-stage sheath 200, the overall strength of the integrated temperature and pressure sensor can be improved, preventing it from loosening due to vibration. The potting compound also protects the lead terminals and electrical connections inside the second-stage sheath 200 from corrosion by moisture, salt spray, electrolyte, and other substances. By filling the front and rear ends of the stainless steel sheath 300 with flexible silicone grease and rigid potting compound respectively, the soft silicone grease at the front end can absorb some of the stress from thermal expansion and contraction, preventing damage to the fragile internal temperature-sensing element. The rigid potting compound at the rear end provides stable support, ensuring the stability of the integrated temperature and pressure sensor measurement and improving its lifespan.

[0031] In one embodiment, the sum of the thickness of the first-level sheath 100 and the thickness of the metal plating layer is equal to the thickness of the second-level sheath 200. The thickness of the first-level sheath 100 is 0.15~0.2mm, which, while ensuring the structural integrity and mechanical strength of the integrated temperature and pressure sensor, can minimize the thermal resistance of the first-level sheath 100. The thickness of the metal plating layer is 2.67~3.75um, and the thickness of the second-level sheath 200 is 0.15~0.21mm. During processing, the stainless steel sheath 300 is first processed into a stepped integral sheath using precision cold drawing or CNC turning. Then, the thicknesses of the first-level sheath 100 and the second-level sheath 200 are set according to the target dimensions. To ensure a smooth transition between the outer walls of the first-level sheath 100 and the second-level sheath 200, the geometry of the transition area is set as a micro-conical surface or an arc surface.

[0032] In this embodiment, by setting the thickness of the first-level sheath 100 with the metal coating to be equal to the thickness of the second-level sheath 200, it can be ensured that the outer walls of the first-level sheath 100 and the second-level sheath 200 can be smoothly and continuously connected in the axial direction, ensuring that there are no steps or abrupt changes, avoiding stress concentration caused by sudden changes in cross-section, enhancing the bending and vibration resistance of the stainless steel sheath 300 at the connection between the first-level sheath 100 and the second-level sheath 200, and improving the reliability of the integrated temperature and pressure sensor.

[0033] In one embodiment, the ratio of the thickness of the metal coating to the thickness of the first-stage sheath 100 is between 1:75 and 1:40. The thickness of the first-stage sheath 100 is 0.15~0.2mm, and the thickness of the metal coating is 2.67~3.75um. If the metal coating is too thin, for example, the ratio is close to or less than 1:75, its effect on improving the thermal conductivity of the integrated temperature and pressure sensor is limited, and pitting corrosion may occur in harsh environments, reducing the ion migration blocking ability. However, when the metal coating is too thick, for example, the ratio is close to or greater than 1:40, although it can further improve the thermal conductivity and corrosion resistance of the integrated temperature and pressure sensor, the excessively thick metal coating will cause internal stress accumulation, which can easily lead to cracking or even peeling of the metal coating, and will increase costs.

[0034] In this embodiment, by setting the ratio of the thickness of the metal plating layer to the thickness of the first-level plastic sheath 100 to between 1:75 and 1:40, it is possible to reduce the thermal resistance of the first-level sheath 100 and improve the thermal response speed, while avoiding cracking and peeling of the metal plating layer on the outer wall of the first-level sheath 100 due to excessive internal stress, thus ensuring the measurement stability of the integrated temperature and pressure sensor and improving its lifespan and reliability.

[0035] In one embodiment, the metal plating includes a nickel plating layer and a gold plating layer, and the thickness ratio of the nickel plating layer to the gold plating layer is between 3:5 and 5:1. The nickel plating layer is formed on the outer wall of the first-stage sheath 100 using an electroplating process, and then the gold plating layer is deposited on the outer wall of the nickel plating layer using an electroplating or chemical plating process. The nickel plating layer can form a strong metallurgical bond with the first-stage sheath 100, providing a foundation for the subsequent adhesion of the gold plating layer. If the nickel plating layer is too thin, for example, if the ratio is close to or less than 3:5, the effect of the nickel plating layer as a bonding underlayer will be significantly reduced, which may lead to insufficient adhesion of the gold plating layer, or diffusion problems of matrix elements in the first-stage sheath 100 during subsequent use, affecting the performance of the gold plating layer. If the nickel plating layer is too thick, for example, if the ratio is close to or greater than 5:1, the excessively thick nickel plating layer may increase the thermal resistance of the metal plating layer, reduce the thermal response speed of the integrated temperature and pressure sensor, and also lead to increased internal stress and increased cost.

[0036] In this embodiment, by setting the metal plating layer as a composite plating structure of nickel plating and gold plating, the nickel plating layer provides good adhesion to the gold plating layer, ensuring that the gold plating layer will not peel off during subsequent use. Furthermore, the nickel plating layer can also provide a barrier to the gold plating layer, preventing metal atoms from the first-level sheath 100 from diffusing into the gold plating layer under high temperature or long-term use, further preventing the gold plating layer from being contaminated and failing. By setting the ratio of the thickness of the nickel plating layer to the thickness of the gold plating layer to between 3:5 and 5:1, the thermal response speed of the integrated temperature and pressure sensor can be improved while reducing costs and increasing the reliability and lifespan of the integrated temperature and pressure sensor.

[0037] In one embodiment, the preparation of the metal coating in step S12 includes the following steps: Step S101: Perform pretreatment on the stainless steel sheath 300, wherein the pretreatment temperature is 50~80℃ and the pretreatment time is 30s~5mins; perform chemical degreasing, water washing, acid pickling activation, secondary water washing and drying on the stainless steel sheath 300 in sequence. The degreasing solution can be a solution containing sodium hydroxide, sodium carbonate and surfactant, and the degreasing temperature is 50-80℃. The acid pickling activation solution can be dilute sulfuric acid, dilute hydrochloric acid or a mixture thereof, and the acid pickling time is 30s-5mins. Through the above pretreatment steps, the surface oil, rust and oxide layer of the stainless steel sheath 300 are removed to ensure that its surface is clean and rough and enhances the bonding force.

[0038] Step S102: Pre-plat the nickel layer on the outer wall of the first-stage sheath 100 after pretreatment, wherein the pre-plating current density is 1~5A / dm.2 The nickel plating layer is pre-plated onto the outer wall of the first-stage sheath 100 after pretreatment using an electroplating process. The current density of the electroplating process is 1-5 A / dm³. 2 This ensures the adhesion between the nickel plating layer and the first-level sheath 100.

[0039] Step S103: Using electroplating or chemical plating processes, deposit the gold plating layer on the outer wall of the first-level sheath 100 to form the metal plating layer; a continuous gold plating layer with uniform thickness, dense crystals and low porosity can be deposited on the outer wall of the nickel plating layer using electroplating or chemical plating processes. The gold plating layer is in direct contact with the external environment, thereby improving the thermal response speed of the integrated temperature and pressure sensor.

[0040] In this embodiment, the stainless steel sheath 300 is pre-treated to ensure that its surface is clean and rough, thereby improving the adhesion between it and the subsequent metal plating layer and fundamentally preventing the metal plating layer from falling off. The pre-plated, flat and dense nickel plating layer serves as the bottom layer, which ensures the uniform deposition of the gold plating layer and can prevent the metal atoms of the first-stage sheath 100 from damaging the gold plating layer.

[0041] In one embodiment, the gold plating layer is deposited on the outer wall of the first-stage sheath 100 using an electroplating process to form the metal plating layer, wherein the electroplating temperature is 20~60°C and the current density is 0.5~3A / dm³. 2 The pH value is 4-6; the gold plating layer is formed by depositing it on the outer wall of the nickel plating layer using an electroplating process. During electroplating, the stainless steel sheath 300 is used as the cathode and immersed in the gold plating solution. This application selects a gold salt solution as the electrolyte, with a gold salt concentration of 5-20 g / L, a pH value of 4-6, a temperature of 20-60℃, and a current density of 0.5-3 A / dm³. 2 Using this process, gold ions are deposited under the action of an electric current to form the gold plating layer. The deposition rate is controllable, the uniformity of the plating layer is good, and it is easy to achieve automated production.

[0042] Alternatively, a chemical plating process can be used to deposit the gold plating layer on the outer wall of the first-stage sheath 100 to form the metal plating layer, wherein the temperature of the chemical plating is 60~90℃. This process relies on a reducing agent (e.g., sodium hypophosphite) in the plating solution to chemically reduce gold ions and deposit them on the surface of the nickel plating layer. This process controls the deposition rate and plating quality by controlling the concentration of the reducing agent, temperature and pH value. This process does not require electricity and the plating layer has strong coverage.

[0043] After the gold plating layer is formed, the stainless steel sheath 300 is post-treated by washing it with room temperature water and drying it at 60-100℃ to prevent the metal plating layer from corroding or discoloring.

[0044] In another embodiment, the metal coating may also be a titanium plating layer. If it is a titanium plating layer, after the surface oil, rust, and oxide layer of the stainless steel sheath 300 are removed by pretreatment, it is placed in a vacuum coating machine and vacuumed to 10°C. -3 ~10 -4 After removing air impurities, an inert gas (such as argon) is introduced at a flow rate of 10-50 sccm. A negative bias voltage of 500-1000V is applied, and high-energy ions bombard the workpiece surface for 5-15 minutes to further purify and activate the surface of the stainless steel sheath 300. Then, the titanium target is ionized into titanium ions by magnetron sputtering, arc ion plating, etc., and a titanium plating layer or titanium compound plating layer is deposited on the surface of the first-stage sheath 100. The target current is 5-30A, and the deposition temperature is 150-500℃. After the titanium plating layer is formed, the stainless steel sheath 300 is post-processed, vacuum cooled, and then removed. Polishing or testing of the plating performance is performed if necessary.

[0045] In one embodiment, after step S13, the method further includes: Step S14: providing an adapter, wherein the adapter has a boss at one end facing the temperature sensing module, the outer diameter of the boss being smaller than the inner diameter of the second-level sheath 200, and the second-level sheath 200 is fitted onto the boss. The boss has a cylindrical cross-section, and its outer diameter is smaller than the inner diameter of the second-level sheath 200. The two are connected by an interference fit, and epoxy resin is applied to the mating surfaces to enhance the connection strength between the boss and the second-level sheath 200. After step S13 is completed, epoxy resin is immediately applied to the outer wall of the boss, and the stainless steel sheath 300 and the adapter are aligned and pressed together. Then, the entire assembly is placed in a curing oven for curing, so that the stainless steel sheath 300 and the adapter form an integral structure.

[0046] In this embodiment, potting compound is used to bond the stainless steel sheath 300 to the adapter, forming a tight connection between the two. This prevents the integrated temperature and pressure sensor from undergoing axial displacement or circumferential rotation during subsequent use, thus improving the stability of the integrated temperature and pressure sensor. At the same time, the cured potting compound can also form a seal between the second-level sheath 200 and the boss, preventing external moisture, salt spray, oil, electrolyte, and other impurities from entering the integrated temperature and pressure sensor and causing contamination, further improving the reliability and lifespan of the integrated temperature and pressure sensor.

[0047] In one embodiment, after step S14, the method further includes: step S15: providing a sealing ring, the sealing ring being fitted onto the outer wall of the connection between the second-stage sheath 200 and the boss. The sealing ring is an O-ring, made of a high-temperature, oil-resistant, and chemically resistant material, and is fitted onto the outer wall of the connection between the second-stage sheath 200 and the boss to form a seal between the second-stage sheath 200 and the external device after the integrated temperature and pressure sensor is installed on the external device.

[0048] In this embodiment, by setting a sealing ring on the outer wall of the connection between the second-level sheath 200 and the boss, the internal moisture, dust and other impurities of the integrated temperature and pressure sensor can be completely isolated from the external environment, avoiding contamination of the internal temperature and pressure sensor and further improving the reliability and lifespan of the integrated temperature and pressure sensor.

[0049] Please refer to the figure, which is a schematic diagram of the structure of the integrated temperature and pressure sensor provided in an embodiment of this application. The integrated temperature and pressure sensor includes: A temperature sensing module is used to measure temperature signals; the temperature sensing module includes a temperature sensing element and lead terminals, the temperature sensing element is used to collect temperature change values; the lead terminals are electrically connected to the temperature sensing element.

[0050] A pressure sensing module is used to measure pressure signals. The pressure sensing module includes a pressure-sensitive chip, a pressure interface, and a signal processing circuit. The pressure-sensitive chip can be a piezoresistive or capacitive pressure-sensing element, which is connected to the pressure interface through glass micro-fusion or silicon-silicon bonding processes. The pressure interface has an external thread or flange structure for communicating with the measured medium. The output signal of the pressure sensing module is amplified and digitized by the signal processing circuit to output an electrical signal.

[0051] A stainless steel sheath 300 includes at least a first-stage sheath 100 and a second-stage sheath 200 connected sequentially along the axial direction. The thickness of the first-stage sheath 100 is less than the thickness of the second-stage sheath 200, and the outer wall of the first-stage sheath 100 is provided with a metal plating layer. The stainless steel sheath 300 is generally a stepped, slender cylinder, divided into at least a first-stage sheath 100 and a second-stage sheath 200 connected sequentially along the axial direction. The shape of the first-stage sheath 100 matches the shape of the temperature sensing element and covers the temperature sensing element; the second-stage sheath 200 covers the lead terminal. The first-stage sheath 100 and the second-stage sheath 200 are connected by integral molding, and the connection between the two has a smoothly transitioned stepped structure to avoid stress concentration and cracking. The thickness of the first-stage sheath 100 is less than the thickness of the second-stage sheath 200. The wall thickness of the first-stage sheath 100 is controlled between 0.14 and 0.20 mm, preferably 0.17 mm, and the wall thickness of the second-stage sheath 200 is controlled between 0.15 and 0.21 mm, preferably 0.18 mm. The outer wall of the first-stage sheath 100 is provided with a metal plating layer, which includes a nickel plating layer in close contact with the outer wall of the first-stage sheath 100 and a gold plating layer in close contact with the nickel plating layer. The nickel plating layer is achieved by electroplating, and the gold plating layer can be formed by electroplating or chemical plating.

[0052] In this embodiment, by reducing the thickness of the first-stage sheath 100 and providing a highly thermally conductive metal coating on its outer wall, the heat capacity and thermal resistance are reduced, thereby reducing the thermal response time and improving the heat conduction efficiency, enabling the integrated temperature and pressure sensor to measure temperature quickly and accurately. Furthermore, the metal coating has excellent anti-corrosion and anti-ion migration properties, which can resist the erosion of external moisture, corrosive fluids, dust and other impurities, improving the reliability of the integrated temperature and pressure sensor and extending its lifespan. The thicker second-stage sheath 200 can provide sufficient support strength to ensure the stability of the integrated temperature and pressure sensor in the installation or vibration environment, preventing it from deforming or being damaged.

[0053] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0054] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included 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 method for fabricating a temperature and pressure integrated sensor, characterized in that, Includes the following steps: Step S11: Provide a temperature sensing module and a pressure sensing module, wherein the temperature sensing module and the pressure sensing module are used to measure temperature signals and pressure signals, respectively; Step S12: Provide a stainless steel sheath, the stainless steel sheath comprising at least a first-level sheath and a second-level sheath connected sequentially along the axial direction, controlling the thickness of the stainless steel sheath such that the thickness of the first-level sheath is less than the thickness of the second-level sheath, wherein the outer wall of the first-level sheath is provided with a metal plating layer, and the outer wall of the second-level sheath is not provided with the metal plating layer. Step S13: Inject thermally conductive silicone grease into the first-stage sheath and inject potting compound into the second-stage sheath.

2. The method for preparing the integrated temperature and pressure sensor according to claim 1, characterized in that, In step S13: the area where thermally conductive silicone grease is injected into the first-level sheath is consistent with the area covered by the metal plating.

3. The method for preparing the integrated temperature and pressure sensor according to claim 1, characterized in that, The sum of the thickness of the first-level sheath and the thickness of the metal plating layer is equal to the thickness of the second-level sheath.

4. The method for preparing the integrated temperature and pressure sensor according to claim 1, characterized in that, The ratio of the thickness of the metal plating to the thickness of the first-level sheath is between 1:75 and 1:

40.

5. The method for preparing the integrated temperature and pressure sensor according to claim 1, characterized in that, The metal plating layer includes a nickel plating layer and a gold plating layer, and the ratio of the thickness of the nickel plating layer to the thickness of the gold plating layer is between 3:5 and 5:

1.

6. The method for preparing the integrated temperature and pressure sensor according to claim 5, characterized in that, The preparation of the metal coating in step S12 includes the following steps: Step S101: Perform a pretreatment on the stainless steel sheath, wherein the temperature of the pretreatment is 50~80℃ and the time of the pretreatment is 30s~5mins; Step S102: Pre-plat the nickel layer on the outer wall of the first-stage sheath after pretreatment, wherein the pre-plating current density is 1~5A / dm. 2 ; Step S103: Using electroplating or chemical plating processes, deposit the gold plating layer on the outer wall of the first-level sheath to form the metal plating layer.

7. The method for preparing the integrated temperature and pressure sensor according to claim 6, characterized in that, The gold plating layer is deposited on the outer wall of the first-stage sheath using an electroplating process to form the metal plating layer. The electroplating temperature is 20~60℃, and the current density is 0.5~3A / dm³. 2 The pH value is 4~6; or, The gold plating layer is deposited on the outer wall of the first-level sheath using a chemical plating process to form the metal plating layer, wherein the temperature of the chemical plating is 60~90℃.

8. The method for preparing the integrated temperature and pressure sensor according to claim 1, characterized in that, The process after step S13 also includes: Step S14: Provide an adapter, the adapter having a boss at one end facing the temperature sensing module, the outer diameter of the boss being smaller than the inner diameter of the second-level sheath, and the second-level sheath being fitted onto the boss.

9. The method for preparing the integrated temperature and pressure sensor according to claim 8, characterized in that, The process after step S14 also includes: Step S15: Provide a sealing ring, which is fitted onto the outer wall of the connection between the second-stage sheath and the boss.

10. A temperature and pressure integrated sensor, prepared using the method for preparing a temperature and pressure integrated sensor as described in any one of claims 1-9, characterized in that, include: Temperature sensing module, used to measure temperature signals; Pressure sensing module, used to measure pressure signals; A stainless steel sheath, comprising at least a first-stage sheath and a second-stage sheath connected sequentially along the axial direction, wherein the thickness of the first-stage sheath is less than the thickness of the second-stage sheath, and the outer wall of the first-stage sheath is provided with a metal plating layer.

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