Micro pressure sensor single piece flow calibration system, method and assembly line for automotive

Abstract

The application provides a micro pressure sensor single-piece flow calibration system, method and assembly line for automobiles. The system comprises a normal temperature environment calibration unit and a high temperature calibration circulation unit. The normal temperature environment calibration unit comprises a first pressure controller, a first control valve group and a first split type sealing tool, and is used for initial pressure calibration of the sensor in a normal temperature environment. The high temperature calibration circulation unit comprises a second pressure controller, a second control valve group, a second split type sealing tool, a segmented tunnel furnace, a temperature control module and a closed loop pressure control module, and is used for circulation calibration of the sensor in a preset temperature range. The application effectively solves the technical problems of unstable pressure control, poor sealing performance and uneven temperature field in the high temperature calibration link of the existing micro pressure sensor single-piece flow calibration system, resulting in low calibration accuracy and poor product consistency.

Description

Technical Field

[0001] This application belongs to the field of automotive sensor manufacturing technology, specifically relating to a calibration system, calibration method, and automated assembly line integrating the calibration system for a micro pressure sensor used in the thermal management system of new energy vehicles. Background Technology

[0002] With the rapid development of the new energy vehicle industry, thermal management systems are placing higher demands on the measurement accuracy, reliability, and production consistency of miniature pressure sensors. As a key detection component in the thermal management system, the performance of miniature pressure sensors directly affects the energy efficiency and safety of the entire vehicle.

[0003] Currently, the calibration and assembly processes for traditional pressure sensors are mostly decentralized operations. Specifically, room temperature calibration, high and low temperature cycle calibration, performance testing, and assembly are usually completed independently on different equipment, requiring manual transfer of sensors between different workstations. In the high-temperature calibration stage, existing equipment suffers from problems such as unstable pressure control, poor sealing performance, and uneven temperature field. Specifically, ordinary pressure controllers lack accuracy and are prone to leakage when used with simple sealing fixtures, resulting in large fluctuations in calibration pressure and distortion of sensor temperature drift data; traditional box furnaces have poor temperature field uniformity and uncontrollable heating rates, leading to uneven heating of the sensor and making it difficult to guarantee the reliability of temperature drift calibration data.

[0004] In addition, under the decentralized operation mode, calibration and test data rely heavily on manual recording, lacking a fully automated data collection and traceability mechanism. Non-conforming parts are difficult to identify and isolate in a timely manner, and are prone to flowing into subsequent processes, resulting in problems such as high rework costs and low production efficiency. Summary of the Invention

[0005] This application provides a single-piece flow calibration system, method, and assembly line for automotive micro pressure sensors, which solves the technical problems of unstable pressure control, poor sealing performance, and uneven temperature field in the high-temperature calibration process of existing micro pressure sensor single-piece flow calibration systems, resulting in low calibration accuracy and poor product consistency.

[0006] In a first aspect, embodiments of this application provide a single-piece calibration system for a micro pressure sensor used in automobiles, comprising: a room temperature environment calibration unit and a high temperature calibration cycle unit; wherein: the room temperature environment calibration unit includes a first pressure controller, a first control valve group and a first split-type sealing fixture, used for initial pressure calibration of the sensor under room temperature conditions; the high temperature calibration cycle unit includes a second pressure controller, a second control valve group, a second split-type sealing fixture, a segmented tunnel furnace, a temperature control module and a closed-loop pressure control module, used for cyclic calibration of the sensor within a preset temperature range.

[0007] In one implementation of this embodiment, the first split sealing fixture and the second split sealing fixture respectively include an upper mold base, a lower mold base, and a radial sealing assembly; the radial sealing assembly adopts a double-layer composite structure of metal hard seal and fluororubber flexible seal.

[0008] In one implementation of this embodiment, the mating surface between the metal hard seal and the sensor housing is a mirror surface, and the surface roughness of the mirror surface is ≤Ra0.4; the compression of the fluororubber flexible seal is 15%~20%.

[0009] In one implementation of this embodiment, the first control valve group adopts a combination control method of proportional valve and on / off valve, and uses PID closed-loop regulation to control the pressure.

[0010] In one implementation of this embodiment, the segmented tunnel furnace is divided into a preheating section, a high-temperature insulation section, a cooling section, and a low-temperature insulation section along the conveying direction. Each section is independently equipped with a heating module, a cooling module, and a temperature sensor to achieve wide temperature range cyclic control from -40℃ to 150℃.

[0011] In one implementation of this embodiment, the heating rate of the segmented tunnel furnace is continuously adjustable within the range of 1~10℃ / min, and the temperature field uniformity of the heat preservation section is controlled within ±1℃.

[0012] In one implementation of this embodiment, the segmented tunnel furnace is equipped with a hot air circulation system with top air supply and bottom air return.

[0013] In one implementation of this embodiment, the conveyor line inside the segmented tunnel furnace adopts a high-temperature resistant chain plate, and the high-temperature resistant chain plate is provided with a positioning fixture to control the consistency of the position of the sensor inside the furnace.

[0014] Secondly, this application provides a single-piece calibration method for a micro pressure sensor for automobiles, comprising the following steps: under normal temperature conditions, the sensor is initially calibrated using a first pressure controller and a first split-type sealing fixture; the sensor is then fed into a segmented tunnel furnace, sequentially passing through a preheating section, a high-temperature insulation section, a cooling section, and a low-temperature insulation section, with the temperature independently controlled in each temperature zone, and the pressure maintained stable through a closed-loop pressure control module, thereby achieving wide-temperature-range cyclic calibration of the sensor.

[0015] Thirdly, embodiments of this application provide a single-piece flow calibration, testing, and assembly production line for automotive miniature pressure sensors, comprising, arranged sequentially along the process: the single-piece flow calibration system for automotive miniature pressure sensors as described above; a performance testing module for collecting output voltage data and raw parameters of the sensor during the calibration process; an automatic screening module for automatically isolating unqualified sensors based on test results; an automated assembly module for completing subsequent sensor assembly processes; and a control and data traceability module that communicates with each module to automatically store data and link processes.

[0016] The single-piece calibration system, method, and assembly line for automotive miniature pressure sensors provided in this application have the following advantages:

[0017] 1. This application significantly improves the stability of pressure control and the uniformity of temperature field by equipping both the normal temperature and high temperature calibration units with high-precision pressure controllers and double-layer composite sealing fixtures, and by adopting a segmented independent temperature-controlled tunnel furnace and hot air circulation system. This ensures the reliability of temperature drift calibration data and effectively solves the technical problems of unstable pressure control, poor sealing performance and uneven temperature field in the high temperature calibration process of existing micro pressure sensor single-piece flow calibration systems, which lead to low calibration accuracy and poor product consistency.

[0018] 2. This application integrates full-process data traceability and automatic isolation of non-conforming parts, which greatly improves production efficiency and product yield, and effectively solves the problems of low calibration accuracy, temperature drift data distortion, untraceable data and scattered processes in the existing technology. Attached Figure Description

[0019] Figure 1 The diagram shown is a schematic block diagram of a single-piece flow calibration system for a miniature pressure sensor for automobiles, according to an embodiment of this application.

[0020] Figure 2 The diagram shown is a structural schematic of a high-temperature calibration cycle unit in a single-piece flow calibration system for a micro pressure sensor for automobiles, according to an embodiment of this application.

[0021] Figure 3 The diagram shown is a schematic diagram of the principle structure of a split sealing fixture in a single-piece flow calibration system for a micro pressure sensor for automobiles, according to an embodiment of this application.

[0022] Figure 4 The diagram shown is a schematic diagram of the principle structure of a split sealing fixture in a single-piece flow calibration system for a micro pressure sensor for automobiles, according to an embodiment of this application.

[0023] Figure 5 The diagram shown is a schematic diagram of the principle structure of a segmented tunnel furnace in a single-piece flow calibration system for a micro pressure sensor for automobiles, according to an embodiment of this application.

[0024] Figure 6 The flowchart shown is a single-piece flow calibration method for a micro pressure sensor for automobiles according to an embodiment of this application.

[0025] Figure 7 The diagram shown is a schematic block diagram of a production line for the calibration, testing, and assembly of a micro pressure sensor for automobiles, according to an embodiment of this application.

[0026] Component designation:

[0027] Automotive miniature pressure sensor single-piece calibration system - 100; ambient temperature calibration unit - 110; first pressure controller - 111; first control valve group - 112; first split-type sealing fixture - 113; high temperature calibration cycle unit - 120; second pressure controller - 121; second control valve group - 122; second split-type sealing fixture - 123; upper mold base - 123a; lower mold base - 123b; radial sealing assembly - 123c; segmented tunnel furnace - 124; temperature control module - 125; closed-loop pressure control module - 126; performance testing module - 200; automatic screening module - 300; automated assembly module - 400; control and data traceability module - 500; S100~S200 - steps. Detailed Implementation

[0028] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0029] In existing technologies, traditional production lines typically use ordinary pressure controllers with simple sealing fixtures, which have low pressure control accuracy and are prone to leakage in the sealing structure. This results in large pressure fluctuations during calibration, distorted sensor temperature drift data, and an inability to meet high-precision calibration requirements.

[0030] This embodiment provides a single-piece calibration system, method, and assembly line for automotive miniature pressure sensors, addressing the technical problems of unstable pressure control, poor sealing performance, and uneven temperature field in existing single-piece calibration systems for miniature pressure sensors during high-temperature calibration, leading to low calibration accuracy and poor product consistency. This embodiment sequentially includes a room-temperature calibration unit and a high-temperature calibration cycle unit, both equipped with a high-precision pressure controller and a separate precision sealing fixture. This sealing fixture employs a double-layer composite structure of a hard metal seal and a flexible fluororubber seal. The mating surface between the hard metal seal and the sensor housing is mirror-finished, and the compression of the flexible fluororubber seal is controlled within a reasonable range. Simultaneously, a precision control valve group consisting of a proportional valve and a switching valve is used, achieving rapid pressure establishment and stabilization through PID closed-loop regulation. By sequentially calibrating at room temperature and high temperature, and performing high- and low-temperature cyclic calibration based on initial room-temperature adjustment, pressure fluctuations and leakage risks across the entire temperature range are further suppressed. This solution effectively solves the technical problems of large pressure fluctuations and sensor temperature drift data distortion caused by insufficient accuracy of ordinary pressure controllers and easy leakage of simple sealing fixtures in existing technologies. It achieves high-precision and stable pressure during calibration, significantly improving the calibration accuracy and product consistency of the sensor across the entire temperature range.

[0031] The following will refer to the appendices in the embodiments of this application. Figure 1 To be continued Figure 5 This application provides a detailed description of the technical solutions in its embodiments. This allows those skilled in the art to understand and implement the automotive miniature pressure sensor single-piece flow calibration system, method, and assembly line of this embodiment without inventive effort.

[0032] Example 1

[0033] First, embodiments of this application provide a single-piece flow calibration system for a miniature pressure sensor used in automobiles. Figure 1 The diagram shown is a schematic block diagram of a single-piece flow calibration system for a miniature pressure sensor used in automobiles, according to an embodiment of this application. Figure 1 As shown, the single-piece calibration system 100 for automotive miniature pressure sensors in this embodiment includes: a normal temperature environment calibration unit 110 and a high temperature calibration cycle unit 120.

[0034] The ambient temperature calibration unit 110 includes a first pressure controller 111, a first control valve group 112, and a first split-type sealing fixture 113, used for initial pressure calibration of the sensor under ambient temperature conditions; Figure 2As shown, the high-temperature calibration cycle unit 120 includes a second pressure controller 121, a second control valve group 122, a second split-type sealing fixture 123, a segmented tunnel furnace 124, a temperature control module 125, and a closed-loop pressure control module 126, which are used to cyclically calibrate the sensor within a preset temperature range.

[0035] In the single-piece calibration system 100 for automotive miniature pressure sensors of this embodiment, the ambient temperature calibration unit 110 applies standard pressure to the sensor at room temperature and collects initial output characteristics using a first pressure controller 111, a first control valve group 112, and a first split-type sealing fixture 113 to complete the basic calibration. The high temperature calibration cycle unit 120 performs cyclic pressure calibration on the sensor within a preset wide temperature range using a second pressure controller 121, a second control valve group 122, a second split-type sealing fixture 123, a segmented tunnel furnace 124, a temperature control module 125, and a closed-loop pressure control module 126. It monitors and records the pressure output under temperature changes in real time, thereby obtaining and correcting the temperature drift characteristics of the sensor. The technical benefits of this system are as follows: it significantly improves the stability of pressure control and the reliability of sealing, ensuring small pressure fluctuations and rapid pressure build-up during calibration; the segmented tunnel furnace 124, combined with an independent temperature control module, ensures a uniform temperature field, making the temperature drift calibration data accurate and reliable; the two units are independently configured with pressure control and sealing structures, avoiding mutual interference, improving overall calibration accuracy and product consistency, and laying a technical foundation for full-process automation and data traceability.

[0036] The following provides a detailed description of the ambient temperature calibration unit 110 and the high temperature calibration cycle unit 120 in the single-piece flow calibration system 100 for automotive micro pressure sensors of this embodiment.

[0037] In this embodiment, the first pressure controller 111 of the ambient temperature calibration unit 110 is used to generate a standard pressure medium, the first control valve group 112 is used to regulate the flow rate and on / off state of the pressure medium, and the first split-type sealing fixture 113 is used to form a sealed pressure chamber with the sensor. Under ambient temperature conditions, the sensor is initially calibrated through the coordinated operation of the above components.

[0038] The ambient temperature calibration unit 110 is used to perform initial pressure calibration of the sensor under room temperature conditions. Its specific working process is as follows:

[0039] 1) Sensor positioning and sealing: The sensor to be calibrated is placed in the first split sealing fixture 113, and the closing action of the fixture forms a sealed pressure chamber between the sensor and the sealing fixture.

[0040] 2) Pressure setting and control: The first pressure controller 111 outputs the target pressure value according to the instructions of the host computer. The first control valve group 112 (including proportional valve and on / off valve) responds to the controller signal, adjusts the flow and on / off of the pressure medium, and introduces the standard pressure medium into the sealed chamber of the sealing fixture.

[0041] 3) Pressure Stabilization and Data Acquisition: The first pressure controller 111 monitors the actual pressure value in the chamber in real time and compares it with the target value. Through closed-loop regulation, the pressure is quickly stabilized at the set value. At this time, the sensor core is subjected to standard pressure and generates a corresponding output voltage signal; the performance testing unit simultaneously acquires this voltage signal and raw parameters such as pressure and temperature.

[0042] 4) Multi-point calibration and data storage: Sequentially set multiple different pressure points (such as zero point, midpoint of the range, and full-scale point), and repeat the above pressurization, stabilization, and data acquisition process. All data is uploaded to the host computer after being bound to the sensor's unique ID, and is used to calculate the sensor's offset and gain coefficient to complete the initial calibration at room temperature.

[0043] In one implementation of this embodiment, the first pressure controller 111 employs a Druck PACE6000 precision pressure controller with a control accuracy of ±0.01% FS, capable of closed-loop pressure control within a pressure range of 0~3.5MPa. The first control valve group 112 uses a combination of proportional and on / off valves for control, and achieves rapid pressure establishment and stabilization through PID closed-loop regulation, with a pressure stabilization time ≤2s. The first split-type sealing fixture 113 is used to form a sealed pressure chamber with the sensor, ensuring that the pressure medium acts on the sensor's pressure-sensing core without leakage during calibration.

[0044] like Figure 3 and Figure 4 As shown, in one implementation of this embodiment, the first split sealing fixture 113 and the second split sealing fixture 123 respectively include an upper mold base 123a, a lower mold base 123b and a radial sealing assembly 123c; the radial sealing assembly 123c adopts a double-layer composite structure of metal hard seal and fluororubber flexible seal.

[0045] The mating surfaces of the metal hard seal and the sensor housing are mirror-finished with a surface roughness ≤ Ra0.4, forming the first rigid sealing barrier. The compression of the fluororubber flexible seal is controlled at 15%~20%, forming the second elastic sealing barrier. When the upper mold base 123a is pressed downward under the action of the drive mechanism, the double-layer sealing structure works together to achieve a leak-free pressure seal.

[0046] During the room temperature calibration process, the sensor is first placed on the positioning position of the lower mold base 123b. The upper mold base 123a is then pressed down to ensure a tight seal between the sealing fixture and the sensor housing, forming a sealed pressure chamber. The first pressure controller 111 outputs a standard pressure medium according to the target pressure value set by the host computer. Under the regulation of the PID algorithm, the proportional valve and the on / off valve in the first control valve group 112 quickly and stably introduce the pressure medium into the sealed chamber through the pipeline, ensuring that the standard pressure is accurately applied to the sensor. Simultaneously, the performance testing unit collects the sensor's output voltage signal at this pressure point, binds it to the sensor's unique ID, and uploads it to the host computer, completing the initial pressure calibration.

[0047] The ambient temperature calibration unit 110 in this embodiment effectively solves the problems of large pressure fluctuations and temperature drift data distortion caused by insufficient accuracy of ordinary pressure controllers and easy leakage of simple sealing fixtures in traditional calibration. By adopting the DruckPACE6000 precision pressure controller and PID closed-loop valve group control, high-precision pressure control with pressure fluctuation ≤ ±0.02% FS and pressure stabilization time ≤ 2s is achieved during the calibration process; the double-layer composite structure of metal hard seal and fluororubber flexible seal ensures leak-free sealing under ambient temperature environment, greatly improving the calibration accuracy of the sensor and product consistency.

[0048] In one implementation of this embodiment, the structures of the second pressure controller 121, the second control valve group 122, and the second split-type sealing fixture 123 in the high-temperature calibration cycle unit 120 are the same as those in the normal temperature environment calibration unit 110. They all employ a Druck PACE6000 precision pressure controller, a valve group combining a proportional valve and a switching valve, and a double-layer composite sealing fixture consisting of a metal hard seal and a fluororubber flexible seal. The high-temperature calibration cycle unit 120 is used to cyclically calibrate the sensor within a preset wide temperature range to obtain and correct the sensor's temperature drift characteristics.

[0049] Figure 5 The diagram shown illustrates the principle structure of the segmented tunnel furnace 124 in a single-piece flow calibration system 100 for automotive micro pressure sensors according to an embodiment of this application. Figure 5 As shown, in one implementation of this embodiment, the segmented tunnel furnace 124 is sequentially divided into a preheating section, a high-temperature insulation section, a cooling section, and a low-temperature insulation section along the conveying direction. Each temperature zone is independently equipped with a heating module, a cooling module, and a temperature sensor, achieving wide-range cyclic control from -40℃ to 150℃. The temperature control module 125 is electrically connected to the temperature sensors and actuators of each temperature zone. By independently adjusting the heating or cooling power of each section, each temperature zone can be stabilized within its target temperature range, meeting the calibration requirements of the sensors at different temperature points.

[0050] In one implementation of this embodiment, the heating rate of the segmented tunnel furnace 124 is continuously adjustable within the range of 1~10℃ / min, allowing for flexible setting of the heating speed according to process requirements. Simultaneously, the temperature field uniformity of the holding section is controlled within ±1℃, ensuring that the sensor within this temperature zone is in a uniform temperature environment. Furthermore, the tunnel furnace is equipped with a top-supply, bottom-return hot air circulation system. Forced convection eliminates local temperature gradients, further improving the uniformity of temperature distribution within the furnace, thereby ensuring the accuracy and reliability of temperature drift calibration data.

[0051] In one implementation of this embodiment, the conveyor line within the segmented tunnel furnace 124 employs a high-temperature resistant chain plate to ensure long-term stable operation across a wide temperature range. Positioning fixtures are installed on the high-temperature resistant chain plate to control the consistent positioning of sensors within the furnace, preventing uneven heating or sealing errors caused by placement deviations. The sensors sequentially pass through each temperature zone along with the chain plate. At the calibration station in each temperature zone, a second split-type sealing fixture 123 accurately docks with the sensor to complete pressure loading and data acquisition.

[0052] During the high-temperature calibration process, the second pressure controller 121 and the second control valve group 122, through PID closed-loop regulation, output a stable standard pressure medium to the second split-type sealing fixture 123 inside the furnace. The closed-loop pressure control module 126 monitors the pressure feedback value in real time and compares it with the target value, dynamically adjusting the valve group opening to ensure that the pressure remains stable even under high-temperature conditions. The temperature control module 125 synchronously maintains the set temperature of the current temperature range. While the sensor is subjected to standard pressure, its output voltage signal is acquired by the performance testing unit and bound to the current temperature value, pressure value, and sensor ID to obtain the pressure-output characteristics at that temperature point, completing the full-temperature-range cyclic calibration.

[0053] The high and low temperature calibration unit in this application adopts a segmented tunnel furnace 124 structure, which is divided into a preheating section, a high-temperature insulation section, a cooling section, and a low-temperature insulation section along the conveying direction. Each section is independently equipped with a heating module, a cooling module, and a temperature sensor, achieving precise cyclic control over a wide temperature range of -40℃ to 150℃. Compared with traditional box furnaces, this solution significantly improves the uniformity of the temperature field (uniformity of the insulation section is controlled within ±1℃) through segmented independent temperature control and a hot air circulation system (top air supply, bottom air return), and makes the heating rate continuously adjustable within the range of 1~10℃ / min, solving the problems of uneven temperature field and uncontrollable heating rate in traditional equipment. The sensor is heated uniformly when passing through each temperature zone, avoiding temperature drift calibration errors caused by local temperature gradients, thus ensuring that the repeatability error of the temperature drift calibration data is ≤0.5%. The high-temperature resistant chain plate and positioning fixture ensure the consistency of the sensor's position in the furnace; combined with a high-precision pressure controller and double-layer sealing fixture, leakage-free pressure control in high-temperature environments is achieved. This significantly improves the sensor's calibration accuracy and product consistency across the entire temperature range. Furthermore, combined with a high-precision pressure controller and double-sealed tooling, stable pressure loading is achieved simultaneously in high-temperature environments, further enhancing the reliability of full-temperature calibration and product consistency.

[0054] As can be seen from the above, this embodiment achieves the following technical effects through the coordinated operation of the ambient temperature calibration unit 110 and the high temperature calibration cycle unit 120: The ambient temperature unit adopts a high-precision pressure controller, a valve group combining proportional valves and switching valves, and a double-layer composite tooling with metal hard seals and fluororubber flexible seals, realizing high-stability pressure control and leak-free sealing at ambient temperature, ensuring initial calibration accuracy; the high temperature unit, based on the pressure control of the ambient temperature unit, further introduces a tunnel furnace with segmented independent temperature control, a hot air circulation system, and a closed-loop pressure control module 126, realizing a uniform temperature field and stable high-temperature pressure loading over a wide temperature range, effectively eliminating the interference of temperature gradients on temperature drift calibration. The two units are arranged sequentially along the process, first completing the basic calibration at ambient temperature, and then correcting the temperature drift characteristics of the sensor in high and low temperature cycles, which avoids the limitations of single-unit calibration and ensures the consistency of pressure-temperature response across the entire temperature range. Therefore, the single-piece calibration system for automotive miniature pressure sensors in this embodiment significantly improves the stability of pressure control and sealing reliability, ensures the authenticity and reliability of temperature drift calibration data, and greatly improves the calibration accuracy and product consistency of the sensor across the entire operating temperature range.

[0055] Example 2

[0056] This embodiment provides a single-piece calibration method for a miniature pressure sensor used in automobiles. Figure 6 The flowchart shown is a single-piece calibration method for a miniature pressure sensor for automobiles according to an embodiment of this application. Figure 6As shown, the single-piece calibration method for automotive miniature pressure sensors in this embodiment includes the following steps:

[0057] S100, under normal temperature conditions, performs initial pressure calibration of the sensor through the first pressure controller 111 and the first split-type sealing fixture 113.

[0058] This step is performed at room temperature to obtain the sensor's baseline pressure-output characteristics under room temperature conditions. The specific process is as follows:

[0059] First, the sensor to be calibrated is placed on the positioning position of the lower mold base 123b of the first split-type sealing fixture 113. The upper mold base 123a of the first split-type sealing fixture 113 moves downward under the action of the drive mechanism, pressing the sensor housing, so that the radial sealing component 123c (metal hard seal and fluororubber flexible seal) inside the fixture forms a sealed pressure chamber with the sensor. Subsequently, the first pressure controller 111 outputs a standard pressure medium according to the target pressure value set by the host computer. The proportional valve and on / off valve in the first control valve group 112, under PID closed-loop regulation, precisely control the flow and on / off of the pressure medium, quickly and stably introducing the standard pressure into the sealed chamber, acting on the pressure-sensing core of the sensor. The performance testing unit synchronously collects the output voltage signal of the sensor at this pressure point, binds the data with the sensor's unique ID, and uploads it to the host computer. By sequentially applying multiple preset pressure points (e.g., zero point, full scale, and intermediate point), the input-output relationship curve of the sensor at room temperature is obtained, completing the initial pressure calibration.

[0060] S200, the sensor is fed into the segmented tunnel furnace 124 and passes through the preheating section, high temperature insulation section, cooling section and low temperature insulation section in sequence. The temperature is independently controlled in each temperature zone, and the pressure is kept stable through the closed-loop pressure control module 126 to achieve wide temperature range cyclic calibration of the sensor.

[0061] This step involves feeding the sensor into a segmented tunnel furnace 124, where it sequentially passes through a preheating section, a high-temperature holding section, a cooling section, and a low-temperature holding section. Temperature is independently controlled within each temperature zone, and pressure is maintained stable through a closed-loop pressure control module 126, enabling wide-temperature-range cyclic calibration of the sensor. The specific process is as follows:

[0062] After the sensors complete their room temperature calibration, they enter the segmented tunnel furnace 124 via a high-temperature resistant conveyor belt. The tunnel furnace is divided into a preheating section, a high-temperature insulation section, a cooling section, and a low-temperature insulation section along the conveying direction. Positioning fixtures are installed on the conveyor belt to ensure the consistent position of each sensor inside the furnace.

[0063] In the preheating section, the temperature control module 125 activates the heating module, gradually raising the furnace temperature from room temperature to near the target temperature of the high-temperature insulation section. The heating rate can be continuously adjusted according to process requirements. During the preheating process, the closed-loop pressure control module 126 controls the second pressure controller 121 and the second control valve group 122 to output a stable standard pressure to the second split-type sealing fixture 123. The performance testing unit collects the sensor's output voltage at this temperature and pressure in real time.

[0064] The sensor then enters a high-temperature insulation zone. The temperature in this zone is maintained at a set high value (e.g., 125°C), and temperature uniformity is ensured by independent temperature control and a hot air circulation system. The closed-loop pressure control module 126 continuously maintains stable pressure and collects the sensor's pressure-output data at the high-temperature point.

[0065] Next, the cooling phase begins. The temperature control module 125 activates the cooling module, gradually lowering the furnace temperature to the target temperature of the low-temperature insulation phase. During this process, the closed-loop pressure control module 126 maintains stable pressure and records the sensor output changes during the cooling process.

[0066] Finally, the sensor enters the low-temperature holding phase. The temperature in this phase is maintained at a set low temperature (e.g., -40℃), while the pressure remains stable and data is collected. As needed, the above cycle of heating-holding-cooling-low temperature can be repeated multiple times to obtain the sensor's complete temperature drift characteristics across the entire temperature range.

[0067] At each calibration station within each temperature range, the second split-type sealing fixture 123 docks with the sensor and applies standard pressure. All collected temperature, pressure, and output voltage data are bound to the sensor ID and uploaded to the host computer. The host computer analyzes the full-temperature-range data, calculates the sensor's temperature drift compensation coefficient, and burns it into the sensor's internal memory, completing the wide-temperature-range cyclic calibration.

[0068] The single-piece calibration method for automotive miniature pressure sensors in this embodiment is based on the aforementioned calibration system, and the same technical features will not be repeated. The method includes: First, under normal temperature conditions, the sensor undergoes initial pressure calibration using a first pressure controller 111 and a first split-type sealing fixture 113. The pressure is rapidly established and stabilized using a first control valve group 112 and PID closed-loop regulation, and the pressure-output characteristics at normal temperature are collected. Then, the sensor is fed into a segmented tunnel furnace 124, sequentially passing through a preheating section, a high-temperature insulation section, a cooling section, and a low-temperature insulation section. The temperature is independently controlled within each temperature zone, and the pressure is kept stable through a closed-loop pressure control module 126. Pressure-output data at different temperature points are collected in real time during the wide-temperature-range cycling process, thereby obtaining the sensor's temperature drift characteristics. This method achieves accurate calibration of the sensor across its entire operating temperature range through the synergy of initial calibration at normal temperature and cyclic calibration at high temperature. Through these two steps, the automotive miniature pressure sensor method in this embodiment achieves a complete process from initial calibration at normal temperature to cyclic calibration across a wide temperature range, ensuring the measurement accuracy and consistency of the sensor across its entire operating temperature range.

[0069] Example 3

[0070] To address the problems of fragmented calibration, testing, and assembly processes, low efficiency due to manual handling, and susceptibility to errors, this embodiment provides an integrated solution. Specifically, the production line integrates room temperature calibration, high and low temperature cycle calibration, performance testing, defective part isolation, and automated assembly processes onto a single conveyor line. This conveyor line is driven by servo motors, enabling precise positioning and transport of sensors between units. Furthermore, the conveyor cycle is synchronized with the working cycle of each unit, eliminating the need for manual transfer. Simultaneously, the automated assembly unit is equipped with an automatic feeding mechanism, a pressing mechanism, and a detection mechanism. Based on signals from the central control traceability system, it performs assembly only on qualified sensors, avoiding unnecessary processing of defective parts. Through this integrated design, the production line's efficiency is increased by over 40%, errors caused by manual handling are eliminated, and consistency between processes is ensured.

[0071] Specifically, this embodiment provides a production line for the calibration, testing, and assembly of a single component of a miniature pressure sensor for automobiles. Figure 7 The diagram shown is a schematic block diagram illustrating the calibration, testing, and assembly production line for a micro pressure sensor for automobiles, according to an embodiment of this application. Figure 7As shown, the automotive micro pressure sensor single-piece flow calibration, testing, and assembly production line in this embodiment includes the following components arranged sequentially along the process: the automotive micro pressure sensor single-piece flow calibration system 100 as described above; a performance testing module 200, used to collect the output voltage data and raw parameters of the sensor during the calibration process; an automatic screening module 300, used to automatically isolate unqualified sensors based on the test results; an automated assembly module 400, used to complete the subsequent assembly process of the sensor; and a control and data traceability module 500, which communicates with each module to automatically store data and link processes.

[0072] The automotive miniature pressure sensor single-piece calibration system 100 used in this embodiment, as described above, consists of a room temperature environment calibration unit 110 and a high temperature calibration cycle unit 120. The room temperature environment calibration unit 110 includes a first pressure controller 111, a first control valve group 112, and a first split-type sealing fixture 113, used for initial pressure calibration of the sensor at room temperature. The high temperature calibration cycle unit 120 includes a second pressure controller 121, a second control valve group 122, a second split-type sealing fixture 123, a segmented tunnel furnace 124, a temperature control module 125, and a closed-loop pressure control module 126, used for cyclic calibration of the sensor within a preset temperature range. Through the sequential cooperation of the two units, the pressure-output characteristics of the sensor across the entire temperature range are obtained, providing benchmark data for subsequent performance testing.

[0073] In this embodiment, the performance testing module 200 integrates a voltage acquisition module, a data processing module, and a barcode scanning module. During the calibration process, the performance testing module 200 acquires the sensor's output voltage data and raw parameters (including pressure values, temperature values, etc.) in real time, and reads the unique ID of each sensor through barcode scanning. After binding the acquired data with the sensor ID, it uploads it to the control and data traceability system. The performance testing module 200 can be set up at various temperature zone calibration stations after room temperature calibration and / or during high-temperature cyclic calibration, realizing fully automated acquisition of calibration data throughout the entire process.

[0074] In this embodiment, the performance testing module 200 integrates a voltage acquisition module, a data processing module, and a barcode scanning module. The voltage acquisition module uses a high-precision analog-to-digital converter circuit, which can acquire the weak voltage signals output by the sensor under different pressure and temperature conditions in real time, and convert them into digital quantities for subsequent processing. It has multi-channel synchronous acquisition capability and anti-aliasing filtering function to ensure the authenticity and stability of the acquired data.

[0075] The data processing module incorporates an embedded microprocessor or FPGA, responsible for preprocessing the acquired voltage signals through digital filtering, zero-point calibration, and range normalization. Simultaneously, it receives standard pressure values ​​from the pressure controller and actual temperature values ​​from the temperature control module 125 in real time via a communication interface, aligning the pressure, temperature, and voltage data sets by timestamp to form a complete calibration record. The barcode scanning module employs an industrial-grade laser or image scanner, installed at a fixed position in the calibration station or driven by a small cylinder for telescopic reading. Upon entering the station, the barcode scanning module automatically reads its unique ID barcode, ensuring that each sensor's identity is uniquely traceable throughout the entire production process.

[0076] During the calibration process, the barcode scanning module first obtains the sensor ID, and then the voltage acquisition module continuously reads the sensor's output voltage at a predetermined sampling rate, while simultaneously recording the pressure and temperature values. The data processing module binds these data to the sensor ID, adds a timestamp and workstation number, and uploads them in real time to the central control and traceability system via industrial Ethernet or RS485 communication methods.

[0077] In this embodiment, the performance testing module 200 can be flexibly deployed at multiple key workstations: after room temperature calibration, the initial pressure-output characteristics at room temperature are collected; the performance testing module 200 is set up in the preheating section, high temperature insulation section, cooling section, and low temperature insulation section of the segmented tunnel furnace 124 to independently collect the sensor output, pressure, and temperature at each temperature point, thereby obtaining complete temperature drift curve data; a retesting workstation can also be set up before the automatic screening module 300 for secondary verification.

[0078] In this embodiment, the performance testing module 200 completely replaces the traditional manual recording method, avoiding human errors such as omissions and misrecordings, and ensuring that the calibration data of each sensor is strictly bound to its ID. The data is uploaded to the central traceability system in real time, providing a reliable basis for qualification judgment, temperature drift analysis and quality traceability. Multi-point deployment provides a data source for big data analysis of the entire process, which helps to optimize calibration parameters and improve the consistency and yield of the production line.

[0079] In this embodiment, the automatic sorting module 300 is equipped with a sorting cylinder, a qualified parts conveyor, and a non-qualified parts conveyor. The control and data traceability system, based on preset qualification thresholds (such as pressure deviation, temperature drift error, etc.), marks sensors with unqualified test results as non-qualified parts and sends a control signal to the sorting cylinder to automatically push the non-qualified parts into the non-qualified parts conveyor, achieving physical isolation from qualified parts. This module effectively prevents non-qualified parts from flowing into subsequent assembly processes, reducing rework costs.

[0080] In this embodiment, the sorting cylinder is installed at the corresponding station on the conveyor line, typically after the performance testing module 200 and before the automated assembly module 400. Its push rod end is equipped with a pusher made of flexible material to prevent damage to the sensor housing during rejection. The qualified and unqualified parts channels are located on opposite sides of the conveyor line or in the branching direction, separated by a physical partition to ensure that rejected unqualified parts do not accidentally slip into the qualified parts area.

[0081] In this embodiment, the control and data traceability system has preset pass / fail thresholds. These thresholds can be flexibly configured according to different sensor models and customer requirements. Typical parameters include: allowable range of calibration pressure deviation at room temperature (e.g., ±0.5% FS), upper limit of temperature drift error at high temperature (e.g., ±1.0% FS), and repeatability error limit at low temperature. When the sensor data (pressure value, temperature value, output voltage, etc.) uploaded by the performance testing module 200 is returned to the central system, the system automatically compares the data with the preset thresholds: if all indicators are within the pass / fail range, the sensor is judged as a qualified part; if any indicator exceeds the threshold, the sensor is marked as a unqualified part.

[0082] After the judgment is completed, the control and data traceability system sends a control signal to the sorting cylinder. The signal controls the opening and closing of the solenoid valve through a digital output module (such as the DO point of a PLC or industrial remote I / O), thereby driving the cylinder to move. For defective parts, when the sensor is transported to the sorting station, the system calls the judgment result based on its ID and triggers the cylinder push rod to extend at the precise time point, pushing the sensor laterally into the defective part channel. The stroke and speed of the push rod are adjustable to accommodate sensors of different sizes. For qualified parts, the cylinder remains in its initial retracted state, and the sensor continues to move forward in a straight line into the qualified part channel, flowing to the automated assembly module 400.

[0083] The non-conforming parts conveyor is typically connected to the finished product box or non-conforming parts collection box. Cushioning material can be installed inside the conveyor to prevent damage to the sensors if they fall. Simultaneously, the system can be equipped with an audible and visual alarm device to prompt operators to check equipment status or process parameters when multiple non-conforming parts are detected consecutively. Furthermore, the central traceability system records the ID of each non-conforming part, the reason for non-conformity (specific deviation), the time of non-conformity, and the corresponding process information, facilitating subsequent quality analysis and process improvement.

[0084] Through the aforementioned automatic screening mechanism, this embodiment achieves physical isolation between defective and qualified parts. The entire process requires no manual intervention, completely avoiding the problems of missed or incorrect inspections caused by manual screening. Defective parts are promptly intercepted before the assembly process, preventing ineffective subsequent processing of defective parts, thereby significantly reducing rework costs and material waste, while ensuring the final product's pass rate. Furthermore, the automatic screening module 300 also supports statistical process control (SPC), which can periodically output reports such as defect rate and distribution of defect causes, helping production managers optimize and calibrate processes.

[0085] In this embodiment, the automated assembly module 400 is equipped with an automatic feeding mechanism, a pressing mechanism, and a detection mechanism. Based on signals from the control and data traceability system, this module only performs subsequent assembly processes (such as shell pressing and terminal connection) on sensors that have been determined to be qualified by the automatic screening module 300, avoiding unnecessary processing of unqualified parts. After assembly, the detection mechanism can perform final appearance or functional spot checks on the finished product to ensure factory quality.

[0086] In this embodiment, the automatic feeding mechanism is installed at the end of the qualified part channel and is used to receive sensors that have been determined to be qualified by the automatic screening module 300. Exemplarily, the automatic feeding mechanism consists of a vibratory feeder, a linear feeder, or a gripping robot, capable of feeding qualified sensors into the assembly station in the correct orientation and sequence. The automatic feeding mechanism is linked to the control and data traceability system: when the system determines that the current sensor is a qualified part, it is allowed to enter the feeding area; if it is a non-qualified part, the feeding mechanism does not operate, and the sensor flows directly into the non-qualified part collection box, thereby avoiding ineffective processing of non-qualified parts.

[0087] In this embodiment, the pressing mechanism is located at the core of the assembly station and includes an upper pressing head, a lower mold base 123b, and a pressure sensor. Once a qualified sensor is precisely positioned on the lower mold base 123b, the control and data traceability system sends a start signal to the pressing mechanism. Driven by a servo motor or cylinder, the upper pressing head moves downwards at a set pressure and speed, pressing the sensor housing against the internal circuit board or terminals to complete the housing encapsulation or terminal connection. During the pressing process, the pressure sensor monitors the pressing force value in real time and feeds the data back to the control system to ensure that the pressing quality meets the process requirements. If the pressing force exceeds the allowable range, the system automatically alarms and suspends assembly to prevent batch defects.

[0088] In this embodiment, the inspection mechanism is located after the pressing process and includes an appearance visual inspection subsystem and a functional sampling inspection subsystem. The appearance visual inspection subsystem uses an industrial camera and light source to photograph the assembled sensor from a specific angle, and identifies appearance defects such as shell scratches, pressing gaps, and terminal misalignment through image processing algorithms. The functional sampling inspection subsystem performs electrical performance retesting on the assembled sensor according to a preset sampling ratio (e.g., 1 sensor out of every 50 produced), including key indicators such as output impedance, insulation resistance, and sealing performance. The sampling inspection results are uploaded to the control and data traceability system, bound to the sensor ID, and used as the basis for determining the quality of the finished product.

[0089] Through the above design, the automated assembly module 400 in this embodiment only performs assembly processes on qualified sensors, avoiding the waste of materials and time caused by ineffective processing. Simultaneously, the closed-loop force control of the pressing mechanism and the visual and functional inspection of the testing mechanism effectively ensure assembly consistency. Defect information discovered by the testing mechanism can be traced back to previous calibration or screening stages, helping to quickly locate the root cause of quality problems and ensuring the final quality of the products leaving the factory.

[0090] In this embodiment, the control and data traceability module 500 is communicatively connected to the calibration system, performance testing module 200, automatic sorting module 300, and automated assembly module 400, respectively. This module performs the following functions: receiving and storing all process data from each sensor starting with material feeding (including feeding time, room temperature calibration data, high and low temperature cycle data, performance test results, assembly process information, etc.); enabling one-click traceability of the entire product production process via sensor ID; and simultaneously, sending control commands to each execution unit (such as pressure controllers, valve groups, sorting cylinders, and assembly mechanisms) according to preset logic to achieve linkage and coordination of process cycles, ensuring efficient and automated operation of the production line.

[0091] The control and data traceability module 500 not only stores the calibration data collected by the online performance testing unit, but also summarizes all process information for each sensor from its entry into the production line, including: feeding time, room temperature calibration data, high and low temperature cycle calibration data, performance test results for each temperature zone, automatic screening and judgment results, and automated assembly process information. All data is linked and indexed through the sensor ID. When it is necessary to query the production process of a product, the operator only needs to enter the ID of the sensor, and the system can retrieve its complete historical data with one click, quickly locating the root cause of potential quality problems (such as large fluctuations in the room temperature calibration pressure of a batch of sensors, or abnormal temperature control in a certain temperature zone).

[0092] Through the sequential arrangement and collaborative operation of the five modules described above, the production line in this embodiment achieves automatic data collection and automatic isolation of non-conforming parts throughout the entire process, completely eliminating the reliance on manual recording and screening. On the one hand, it avoids the problems of missed or incorrect inspections that may be caused by manual operation, reducing rework costs; on the other hand, by binding sensor IDs with data from all processes, it achieves full traceability of product quality, providing reliable data support for rapid tracing of quality problems and process improvement, significantly enhancing the intelligence level and quality management capabilities of the production line.

[0093] The protection scope of the single-piece flow calibration system 100 for automotive miniature pressure sensors described in this application is not limited to the execution order of the steps listed in this embodiment. Any solution implemented by adding, subtracting, or replacing steps in the prior art based on the principles of this application is included within the protection scope of this application.

[0094] In summary, this embodiment significantly improves pressure control stability and temperature field uniformity by equipping both the ambient and high-temperature calibration units with high-precision pressure controllers and double-layer composite sealing fixtures, and by employing a segmented, independently temperature-controlled tunnel oven and a hot air circulation system. This ensures the reliability of temperature drift calibration data and effectively solves the technical problems of unstable pressure control, poor sealing performance, and uneven temperature field in the high-temperature calibration stage of existing micro pressure sensor single-piece flow calibration systems, leading to low calibration accuracy and poor product consistency. This embodiment also integrates full-process data traceability and automatic isolation of non-conforming parts, greatly improving production efficiency and product yield, and effectively solving the problems of low calibration accuracy, distorted temperature drift data, untraceable data, and fragmented processes in existing technologies. Therefore, this application effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0095] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A single-piece calibration system for a miniature pressure sensor used in automobiles, characterized in that, include: A normal temperature environment calibration unit and a high temperature calibration cycle unit; wherein: The ambient temperature calibration unit includes a first pressure controller, a first control valve group, and a first split-type sealing fixture, which is used to perform initial pressure calibration of the sensor under ambient temperature conditions. The high-temperature calibration cycle unit includes a second pressure controller, a second control valve group, a second split-type sealing fixture, a segmented tunnel furnace, a temperature control module, and a closed-loop pressure control module, which are used to cyclically calibrate the sensor within a preset temperature range.

2. The single-piece calibration system for a miniature pressure sensor for automobiles according to claim 1, characterized in that, The first split-type sealing fixture and the second split-type sealing fixture each include an upper mold base, a lower mold base, and a radial sealing assembly; the radial sealing assembly adopts a double-layer composite structure of metal hard seal and fluororubber flexible seal.

3. The single-piece calibration system for automotive miniature pressure sensors according to claim 2, characterized in that, The mating surface between the metal hard seal and the sensor housing is mirror-like, and the surface roughness of the mirror is ≤Ra0.4; the compression of the fluororubber flexible seal is 15%~20%.

4. The single-piece calibration system for a miniature pressure sensor for automobiles according to claim 1, characterized in that, The first control valve group adopts a combination control method of proportional valve and on-off valve, and uses PID closed-loop regulation to control the pressure.

5. The single-piece calibration system for automotive miniature pressure sensors according to claim 1, characterized in that, The segmented tunnel furnace is divided into a preheating section, a high-temperature insulation section, a cooling section, and a low-temperature insulation section along the conveying direction. Each section is independently equipped with a heating module, a cooling module, and a temperature sensor to achieve wide temperature range cyclic control from -40℃ to 150℃.

6. The single-piece calibration system for a miniature pressure sensor for automobiles according to claim 5, characterized in that, The heating rate of the segmented tunnel furnace is continuously adjustable within the range of 1~10℃ / min, and the temperature field uniformity of the heat preservation section is controlled within ±1℃.

7. The single-piece calibration system for a miniature pressure sensor for automobiles according to claim 5, characterized in that, The segmented tunnel furnace is equipped with a hot air circulation system with top air supply and bottom air return.

8. The single-piece calibration system for a miniature pressure sensor for automobiles according to claim 5, characterized in that, The conveyor line inside the segmented tunnel furnace uses a high-temperature resistant chain plate, and the high-temperature resistant chain plate is equipped with a positioning fixture to control the consistency of the sensor's position inside the furnace.

9. A method for single-piece calibration of a miniature pressure sensor for automobiles, characterized in that, Includes the following steps: Under normal temperature conditions, the sensor is initially calibrated using the first pressure controller and the first split-type sealing fixture; The sensor is fed into a segmented tunnel furnace and passes through a preheating section, a high-temperature insulation section, a cooling section, and a low-temperature insulation section in sequence. The temperature is independently controlled in each temperature zone, and the pressure is kept stable through a closed-loop pressure control module to achieve wide-temperature-range cyclic calibration of the sensor.

10. A production line for single-piece calibration, testing, and assembly of a miniature pressure sensor for automobiles, characterized in that, Includes, arranged sequentially along the process: a single-piece flow calibration system for automotive miniature pressure sensors as described in any one of claims 1 to 8; The performance testing module is used to collect the sensor's output voltage data and raw parameters during the calibration process; An automatic screening module is used to automatically isolate unqualified sensors based on test results; An automated assembly module is used to complete the subsequent assembly processes of the sensor; The control and data traceability module communicates and connects with other modules to automatically store data and link processes.

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