A passive NFC aircraft tire temperature and pressure composite sensor system

Abstract

This invention belongs to the field of sensor technology, and specifically relates to a passive NFC aircraft tire temperature and pressure composite sensor system. The system includes: a connector, a back cover, a pressure core, a conversion circuit board, a conditioning circuit board assembly, and a tag antenna assembly. The connector is a two-stage stepped column. The small-diameter end of the connector has an air inlet, and the large-diameter end has a cavity. The pressure core is disposed in the air inlet. The pressure core is connected to the conversion circuit board. The conversion circuit board is connected to the conditioning circuit board assembly. The conditioning circuit board assembly is fixed to the stepped surface of the cavity at the large-diameter end of the connector by a support screw. The tag antenna assembly is mounted on the support screw by a fixing screw. The back cover is screwed to the large-diameter end of the connector. The small-diameter end of the connector is connected to the tire by an external thread.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, and specifically relates to a passive NFC aircraft tire temperature and pressure composite sensor system. Background Technology

[0002] In the field of pressure sensor applications, customers require the design of near-field communication temperature and pressure composite sensors to facilitate the measurement of gas pressure inside aircraft tires in landing gear systems. Traditional wired tire pressure sensors require electrical connectors and cables for power supply, while wired active tire pressure sensors require battery power, are bulky and heavy, and need to be continuously operational during flight, making them unsuitable for the strong magnetic and vibration environments of flight. Summary of the Invention

[0003] The purpose of this invention is to provide a passive NFC aircraft tire temperature and pressure composite sensor system. Based on the principle of near-field communication, it realizes high-precision pressure and temperature composite measurement and output within a non-contact range of 10cm (inclusive). It is small in size and easy to install and remove. The pressure core adopts an inverted structure, which can measure a large pressure range of aircraft tires, and has good anti-electromagnetic interference capability and environmental adaptability.

[0004] The technical solution of this invention is:

[0005] A passive NFC aircraft tire temperature and pressure composite sensor system includes: a connector, a rear cover, a pressure core, a conversion circuit board, a conditioning circuit board assembly, and a tag antenna assembly.

[0006] The nozzle is a two-stage stepped column; the small diameter end of the nozzle is provided with an air inlet, and the large diameter end is provided with a cavity.

[0007] The pressure core is installed in the air inlet; the pressure core is connected to the conversion circuit board;

[0008] The conversion circuit board connects to the conditioning circuit board assembly;

[0009] The conditioning circuit board assembly is fixed to the stepped surface of the large-diameter end cavity of the connector nozzle by support screws;

[0010] The tag antenna assembly is mounted on the support screws using fixing screws;

[0011] The rear cover is screwed onto the large-diameter end of the connector nozzle;

[0012] The small-diameter end of the nozzle is connected to the tire via an external thread.

[0013] Furthermore, the pressure core is welded to and sealed with the air inlet. The air inlet is connected to the inside of the tire to form a sealed cavity as a pressure-sensing chamber, thereby transmitting the medium pressure to the pressure core 10 to achieve pressure measurement. The outer side is designed with a hexagonal shape for easy disassembly using a socket wrench.

[0014] Furthermore, the pressure core includes: a filter element, a silicon piezoresistive chip, a housing, and pins; the housing is a hollow cylinder with a flange at one end; the filter element is welded to the flangeless end face of the housing; the silicon piezoresistive chip is sealed and bonded to the stepped surface of the hollow cylinder; the pins are welded to the pads of the silicon piezoresistive chip; and the flange of the housing is welded to the stepped surface of the inlet port of the connector.

[0015] The pressure core adopts leadless packaging technology. The pin 18 is directly sintered with the pad of the silicon piezoresistive chip 16 through solder, eliminating the gold wire bonding process in traditional packaging and greatly reducing the core size.

[0016] Furthermore, the conditioning circuit board assembly includes: a circuit board motherboard and a metal electromagnetic shielding cover;

[0017] The metal electromagnetic shield is a shield-shaped structure with one end open, and three first threaded holes are opened on the end face;

[0018] There are three second threaded holes at corresponding positions on the main board of the circuit board;

[0019] The support screws pass through the first and second threaded holes to fix the circuit board main board and the metal electromagnetic shielding cover to the stepped surface inside the large diameter end of the connector nozzle;

[0020] The metal electromagnetic shielding cover has wiring holes on its end face. The shielding cover forms a metal shielding cavity, which can effectively protect against external electromagnetic interference.

[0021] Furthermore, the rear end of the support screw is provided with an internal threaded hole; the tag antenna assembly is screwed into the internal threaded hole at the rear end of the support screw by a fixing screw.

[0022] Furthermore, the back cover is made of non-metallic material to avoid shielding the field strength and ensure that the sensor has high temperature resistance, corrosion resistance, and flame retardancy. The product has no internal power source, eliminating the need for frequent disassembly of the end cover. To improve the overall vibration resistance of the sensor, a sealing rubber ring is provided between the back cover and the connector. Thread-locking agent is applied to the threaded connection between the connector 9 and the non-metallic end cover 4, forming a closed shell that provides physical protection for the internal circuitry.

[0023] Furthermore, the conditioning circuit board assembly and the tag antenna assembly are connected by wires, with shielded heat-shrink tubing covering the wires. This enhances the electromagnetic interference resistance of the non-metallic end cap 4.

[0024] Furthermore, the system operates as follows: When a handheld device approaches the system, the tag antenna assembly receives the field strength signal transmitted from the handheld device; the tag antenna assembly converts the field strength signal into an AC signal; the conditioning circuit board assembly converts the AC signal into a stable DC signal to power the pressure core; the pressure core collects the pressure signal; the conditioning circuit board assembly collects temperature data and compensates for the pressure signal based on the temperature data; the compensated pressure and temperature data are transmitted to the handheld device via the tag antenna assembly. The sensor utilizes Near Field Communication (NFC) for wireless, passive temperature and pressure composite monitoring. It is small in size and easy to install and remove. A temperature and pressure composite demodulation circuit based on NFC is designed to achieve non-contact point-to-point communication, enabling composite monitoring of tire pressure and temperature within a 10cm non-contact range.

[0025] The advantages and beneficial effects of this invention are as follows: This invention belongs to the field of sensors and relates to the system design for manufacturing a small-sized, high-pressure passive NFC aircraft tire temperature and pressure composite sensor. In the field of military pressure sensor applications, customers need to obtain high-pressure, high-precision wireless passive pressure and temperature tests on the ground, while also ensuring that the product can withstand various extreme strong magnetic and high vibration environments. This requires reducing the size of the sensor while maintaining reliability. Therefore, the sensor design process necessitates reducing the size of the core pressure element and implementing a passive sensor design, which has significant practical application value.

[0026] Specific advantages:

[0027] 1. The sensor is based on the near field communication (NFC) principle for wireless passive temperature and pressure composite monitoring. It is small in size and easy to install and remove. It does not contain electrical connectors or batteries or other power sources. It can meet the requirements of passive pressure and temperature composite monitoring within a non-contact range of 10cm.

[0028] 2. The sensor uses a small-sized inverted pressure core with high pressure, which can realize the measurement of absolute pressure 0-10MPa;

[0029] 3. The nozzle, outer cylinder, and support are integrated into a single design. The nozzle replaces the function of the outer cylinder and support, reducing welding, miniaturizing the product, and improving structural strength to meet vibration test requirements.

[0030] 4. A metal shielding cover is designed on the conditioning circuit board. The shielding cover is pressed onto the conditioning circuit board by three support screws to form a metal shielding cavity, which meets the requirements of electromagnetic compatibility test assessment. Attached Figure Description

[0031] Figure 1 Cross-sectional view of a pressure sensor;

[0032] Figure 2Schematic diagram of a pressure sensor explosion;

[0033] Figure 3 Cross-sectional view of the pressure-sensitive component;

[0034] Figure 4 Schematic diagram of an explosion of a pressure-sensitive component;

[0035] Figure 5 Cross-sectional view of the pressure core;

[0036] Figure 6 Working principle diagram;

[0037] Figure 7 Schematic diagram of signal conditioning circuit, linear voltage regulator circuit and near-field communication circuit;

[0038] 1. Pressure-sensitive component; 2. Conditioning circuit board assembly; 3. Tag antenna assembly; 4. Non-metallic end cap; 5. Screw; 6. Gasket; 7. Support screw; 8. Sealing rubber ring; 9. Connecting nozzle; 10. Inverted pressure core; 11. Conversion circuit board; 12. Circuit board main board; 13. Metal shield; 14. Through hole; 15. Filter; 16. Silicon piezoresistive chip; 17. Tube shell; 18. Pin. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0040] A system design for a passive NFC aircraft tire temperature and pressure composite sensor comprises a pressure-sensitive component 1, a conditioning circuit board assembly 2, a tag antenna assembly 3, a non-metallic end cap 4, screws 5, washers 6, and support screws 7. The conditioning circuit board assembly 2 has three mounting holes, which are connected to the pressure-sensitive component 1 via wires. The conditioning circuit board assembly 2 and a metal shield 13 are fixed to the threaded holes of a connector 9 by three support screws 7. The tag antenna assembly 3 is fixed to the mounting surface formed by the three support screws 7 by three screws 5 and washers 6, and is connected to the conditioning circuit board assembly 2 via wires.

[0041] To manufacture a small-sized, high-pressure passive NFC aircraft tire temperature and pressure composite sensor, the sensor underwent the following optimization designs.

[0042] The sensor utilizes Near Field Communication (NFC) for wireless, passive temperature and pressure composite monitoring. It is small in size and easy to install and remove. A NFC-based temperature and pressure composite demodulation circuit was designed to achieve non-contact point-to-point communication, enabling composite monitoring of tire pressure and temperature within a 10cm non-contact range.

[0043] The conditioning circuit board assembly 2 consists of a main circuit board 12, a metal electromagnetic shield 13, and a cable pass-through hole 14. The main circuit board 12 includes a signal conditioning circuit, a linear voltage regulator circuit, and a near-field communication circuit. When the tag antenna assembly 3 receives the electromagnetic field strength from the transmitting field, the near-field communication circuit on the main circuit board 12 converts the alternating current signal into a voltage signal, which is then powered by the linear voltage regulator circuit to the signal conditioning circuit and the communication circuit. The signal conditioning circuit generates excitation to power the pressure-sensitive component 1. The pressure-sensitive component 1 senses the pressure of the gas inside the tire. After the conditioning circuit board assembly 2 performs full-temperature compensation on the electrical signal, it connects to the tag antenna assembly 3 to complete the demodulation and transmission of near-field communication data, outputting a non-contact digital signal proportional to the measured medium pressure and temperature.

[0044] 2. A small-sized flip-chip pressure core with high pressure was designed. The pressure core uses a silicon piezoresistive chip as the pressure-sensing element. To meet the requirements of high impact pressure environments, the sensing element needs to be encapsulated. The encapsulation structure of the sensing element consists of a filter 15, a silicon piezoresistive chip 16, a housing 17, and leads 18.

[0045] The filter 15 has a porous structure, which can filter out impurities in the air and prevent impurities from accumulating on the silicon piezoresistive chip 16, causing abnormal chip pressure sensing.

[0046] The pressure-sensing element in the silicon piezoresistive chip 16 uses a silicon film as an elastic sensitive element, and adopts a square flat film form with peripheral fixed support.

[0047] The housing 17 is made of stainless steel, providing physical protection for the internal silicon piezoresistive chip 16.

[0048] The small-sized flip-chip pressure core adopts leadless packaging technology. The pin 18 is directly sintered with the pad of the silicon piezoresistive chip 16 through solder, eliminating the gold wire bonding process in traditional packaging and greatly reducing the core size.

[0049] 3. The nozzle, outer cylinder and support are integrated into one design. The nozzle replaces the function of the outer cylinder and support, reducing welding, realizing product miniaturization while improving structural strength and enhancing the sensor's vibration resistance.

[0050] The connector 9 is made of stainless steel and has good welding compatibility with the pressure core 10. The mechanical interface has external threads for connection to the air inlet of an aircraft tire. An air inlet is designed at the front end, forming a pressure-sensing chamber with the pressure core 10, which is welded to the connector 9, thereby transmitting the medium pressure to the pressure core 10 for pressure measurement. The outer side is hexagonal for easy disassembly using sockets and wrenches.

[0051] The non-metallic end cap 4 has internal threads and an O-ring groove. The O-ring 8 is installed in the O-ring groove of the non-metallic end cap 4 and is connected to the connector 9 by screwing on. It is made of polyetheretherketone material to avoid shielding the electric field strength and ensure that the sensor has high temperature resistance, corrosion resistance, and flame retardancy. The product has no internal power source and does not require frequent disassembly of the end cap. To improve the overall vibration resistance of the sensor, thread-locking agent is applied to the threaded connection between the connector 9 and the non-metallic end cap 4, forming a closed shell with the non-metallic end cap 4 to provide physical protection for the internal circuitry.

[0052] 4. A metal shielding cover 13 is designed on the conditioning circuit board assembly 2. The shielding cover is pressed onto the main board 12 of the circuit board by three support screws 7 to form a metal shielding cavity, which can effectively protect against external electromagnetic interference. Two wire holes 14 are opened on the metal shielding cover. The conditioning circuit board assembly 2 and the tag antenna assembly 3 are connected by wires. The wires are covered with shielded heat shrink tubing to enhance the electromagnetic interference resistance of the non-metallic end cap 4.

[0053] Example

[0054] A system design for a passive NFC aircraft tire temperature and pressure composite sensor comprises a pressure-sensitive component 1, a conditioning circuit board assembly 2, a tag antenna assembly 3, a bracket, a metal outer cylinder, a non-metallic end cap 4, screws 5, washers 6, and support screws 7. The conditioning circuit board assembly 2 has three mounting holes, which are connected to the pressure-sensitive component 1 via wires. The conditioning circuit board assembly 2 and the metal shield 13 are fixed to the threaded holes of the connector 9 by the three support screws 7. The tag antenna assembly 3 is fixed to the mounting surface formed by the three support screws 7 by the three screws 5 and the washers 6, and is connected to the conditioning circuit board assembly 2 via wires.

[0055] The pressure-sensitive component 1 consists of a connector 9, an inverted pressure core 10, and a conversion circuit board 11. By customizing the core housing, the pressure chip is designed as an inverted structure and a leadless packaging technology is adopted. The pins 18 are directly sintered with the pads of the silicon piezoresistive chip 16 through solder, and the housing 17 is connected to the filter 15 by welding.

[0056] The conditioning circuit board assembly 2 consists of a main circuit board 12, a metal electromagnetic shielding cover 13, and wire-passing holes 14. The shielding cover is pressed onto the main circuit board 12 by three support screws 7, forming a metal shielding cavity, which can effectively protect against external electromagnetic interference. Two wire-passing holes 14 are opened on the metal shielding cover, and the conditioning circuit board 2 is connected to the tag antenna assembly 3 by wires. The wires are covered with shielded heat-shrink tubing to enhance the electromagnetic interference resistance of the non-metallic end cap 4. The main circuit board 12 includes a signal conditioning circuit, a linear voltage regulator circuit, and a near-field communication circuit. The tire air inlet is connected to the sensor. When the tag antenna assembly 3 receives the electromagnetic field strength from the transmission field, the near-field communication circuit on the main circuit board 12 converts the alternating current signal into a voltage signal, which is then powered by the linear voltage regulator circuit to the signal conditioning circuit and the communication circuit. The signal conditioning circuit generates current to power the pressure-sensitive component 1. The pressure-sensitive component 1 senses the pressure of the gas inside the tire and converts the pressure signal into a millivolt-level electrical signal. The electrical signal is then compensated for across the entire temperature range by the conditioning circuit board component 2 and connected to the tag antenna component 3 to complete the demodulation and transmission of near-field communication data. The output is a non-contact digital signal that is proportional to the pressure and temperature of the measured medium.

[0057] The tag antenna assembly 3 is wired according to the irregular structure formed by the connector 9 and the support screw 7, and uses a printed circuit board FR-4 as the substrate, which is soldered to the conditioning circuit board assembly 2 through wires.

[0058] The non-metallic end cap 4 is provided with an M27×1-6g internal thread and an O-ring groove, and is made of polyetheretherketone material. It has a built-in tag antenna assembly 3 to avoid blocking the field strength signal.

[0059] The O-ring 8 is installed in the O-ring groove of the non-metallic end cap 4.

[0060] The connector 9 has an M27×1-6H internal thread, is made of stainless steel (0Cr18Ni9 grade), and is integrally welded to the metal outer cylinder, adopting an integrated hexagonal structure. It is connected to the pressure core 10 by laser welding and to the non-metallic end cap 4 by threaded tightening. The connection is coated with thread-locking agent. It also has an M12×1.5-6g external thread, which serves as a mechanical interface for connection with aircraft tires. The front end is designed with an air inlet, which forms a pressure-sensing chamber with the pressure core 10, which is fixed to the connector 9 by welding. This allows the medium pressure to be transmitted to the pressure core 10 for pressure measurement.

[0061] The inverted pressure core 10 consists of a filter element 15, a silicon piezoresistive chip 16, a housing 17, and pins 18. Pins 18 are directly sintered to the pads of the silicon piezoresistive chip 16 using solder. The housing 17 is laser-welded to the filter element 15 and then welded to the nozzle 9.

Claims

1. A passive NFC aircraft tire temperature and pressure composite sensor system, characterized in that, The system includes: a connector, a back cover, a pressure core, a conversion circuit board, a conditioning circuit board assembly, and a tag antenna assembly; The nozzle is a two-stage stepped column; the small diameter end of the nozzle is provided with an air inlet, and the large diameter end is provided with a cavity. The pressure core is installed in the air inlet; the pressure core is connected to the conversion circuit board; The conversion circuit board connects to the conditioning circuit board assembly; The conditioning circuit board assembly is fixed to the stepped surface of the large-diameter end cavity of the connector nozzle by support screws; The tag antenna assembly is mounted on the support screws using fixing screws; The rear cover is screwed onto the large-diameter end of the connector nozzle; The small-diameter end of the connector nozzle is connected to the tire via an external thread. The conditioning circuit board assembly includes: a circuit board main board and a metal electromagnetic shielding cover; the metal electromagnetic shielding cover is a cover-shaped structure with one end open, and three first threaded holes are opened on the end face; three second threaded holes are opened at corresponding positions on the circuit board main board; support screws pass through the first and second threaded holes to fix the circuit board main board and the metal electromagnetic shielding cover to the stepped surface inside the large diameter end of the connector nozzle; the end face of the metal electromagnetic shielding cover has a wire through hole. The support screw has an internal threaded hole at its rear end; the tag antenna assembly is screwed into the internal threaded hole at the rear end of the support screw by a fixing screw. The working process is as follows: When the handheld device approaches the system, the tag antenna assembly receives the field strength signal from the handheld device; the tag antenna assembly converts the field strength signal into an AC signal; the conditioning circuit board assembly converts the AC signal into a stable DC signal to power the pressure core; the pressure core collects the pressure signal; the conditioning circuit board assembly collects temperature data and compensates the pressure signal based on the temperature data; the compensated pressure and temperature data are sent to the handheld device through the tag antenna assembly.

2. The system according to claim 1, characterized in that: The pressure core is welded to and sealed with the air intake, and the air intake is connected to the inside of the tire to form a sealed cavity.

3. The system according to claim 2, characterized in that: The pressure core includes: a filter element, a silicon piezoresistive chip, a housing, and pins; The shell is a hollow cylinder with a flange at one end; The filter element is welded to the flangeless end face of the tube shell; The silicon piezoresistive chip is sealed and bonded to the stepped surface of the hollow cylinder; The pins are soldered onto the pads of the silicon piezoresistive chip; The flange edge of the pipe shell is welded to the stepped surface of the air inlet of the pipe nozzle.

4. The system according to claim 3, characterized in that, The back cover is made of non-metallic material, and a sealing rubber ring is provided between the back cover and the connector.

5. The system according to claim 4, characterized in that, The conditioning circuit board assembly and the tag antenna assembly are connected by wires, and the wires are covered with shielded heat shrink tubing.

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