High temperature wireless temperature probe based on NTC lead time division multiplexing and manufacturing method

Abstract

This application discloses a high-temperature wireless temperature probe and its manufacturing method based on NTC lead time-division multiplexing, relating to the field of wireless temperature probe technology. The high-temperature wireless temperature probe includes: a needle assembly, a ceramic insulating ring, and a coaxial coupling connection shaft connected in sequence; the needle assembly has a built-in PCBA board, on which are integrated: an ambient temperature sensor lead, a time-division multiplexing circuit, and a selective connection to an RF transceiver circuit or an RC charge-discharge temperature measurement circuit; at least two temperature sensors; the ceramic insulating ring is disposed at the junction of the needle assembly and the coaxial coupling connection shaft, forming a sealed cavity; the coaxial coupling connection shaft includes a metal outer wall forming an RF signal ground and a metal inner conductor forming a coaxial transmission structure with the ambient temperature sensor lead. This application effectively eliminates the mutual interference between the RF function and the temperature sensing function of the wireless temperature probe, providing a high-precision temperature measurement performance high-temperature wireless temperature probe.

Description

Technical Field

[0001] This application relates to the field of wireless temperature probe technology, and in particular to a high-temperature wireless temperature probe based on NTC lead time-division multiplexing and its manufacturing method. Background Technology

[0002] Currently, wireless temperature probes are used in scenarios such as food temperature measurement. Existing technologies often employ a single NTC lead multiplexed as an antenna (e.g., US12196619B2). However, this approach has a significant drawback: when the radio frequency signal is coupled to the temperature sensor through the lead, high-frequency noise severely interferes with the temperature measurement accuracy, resulting in a measurement error as high as ±1.5°C. This problem stems from the lack of effective isolation between the physical connection of the lead in radio frequency mode and temperature measurement mode, and the absence of shielding design against electromagnetic interference. Although existing solutions attempt to reduce costs through hardware multiplexing, the core challenge lies in the mutual interference between the radio frequency function and the temperature sensing function, becoming a technical bottleneck restricting high-precision temperature measurement performance. Summary of the Invention

[0003] To address the shortcomings of existing technologies, effectively eliminate the mutual interference between the radio frequency function and temperature sensing function of wireless temperature probes, and provide high-precision temperature measurement performance high-temperature wireless temperature probes, this application provides a high-temperature wireless temperature probe based on NTC lead time-division multiplexing and its manufacturing method.

[0004] Firstly, the objective of this invention is achieved through the following technical solution:

[0005] A high-temperature wireless temperature probe based on NTC lead time-division multiplexing includes: a needle assembly, a ceramic insulating ring, and a coaxial coupling connection shaft connected in sequence; the needle assembly has a built-in PCBA board, and the PCBA board integrates:

[0006] Ambient temperature sensor leads,

[0007] Time-division multiplexing circuit, selectively connected to RF transceiver circuit or RC charge / discharge temperature measurement circuit;

[0008] At least two temperature sensors; the ceramic insulating ring is disposed at the junction of the needle assembly and the coaxial coupling connection shaft, forming a sealed cavity inside;

[0009] The coaxial coupling connection shaft includes:

[0010] The outer metal wall forms the radio frequency signal ground, and the inner metal conductor forms a coaxial transmission structure with the leads of the ambient temperature sensor.

[0011] By adopting the above technical solution, the interference between radio frequency communication and temperature measurement is eliminated based on the time-division multiplexing circuit. By time-division multiplexing the leads of the ambient temperature sensor into a radio frequency antenna and using a coaxial coupling structure to achieve electromagnetic shielding, the interference of radio frequency signals on temperature measurement is effectively eliminated, and the temperature measurement accuracy is improved from ±1.5°C to ±0.3°C. At the same time, by utilizing the thermal expansion compensation design of the ceramic ring and the coaxial shielding characteristics of the metal connecting shaft, the problems of structural cracking and sealing failure under high temperature environment are solved, the overall volume is reduced, and the production yield is improved.

[0012] In a preferred embodiment of this application, the time-division multiplexing circuit includes:

[0013] The first switching module controls the connection and disconnection between the radio frequency matching circuit and the lead of the ambient temperature sensor.

[0014] The second switch module controls the connection and disconnection between the temperature measuring circuit and the lead of the ambient temperature sensor.

[0015] The control unit coordinates the timing actions of the first and second switch modules; the first and second switch modules switch between radio frequency mode and temperature measurement mode through the common I / O port of the control unit.

[0016] By adopting the above technical solution, the radio frequency and temperature measurement circuits are time-division multiplexed, eliminating the interference of high-frequency noise on the temperature sensor and improving the accuracy and reliability of data transmission.

[0017] In a preferred embodiment of this application: the ambient temperature sensor lead multiplexing method includes a single-lead mode; in the single-lead mode...

[0018] The first switching module includes an RF switch and a capacitor. One end of the RF switch is coupled to a lead of the ambient temperature sensor through the capacitor, and the other end is coupled to the control unit through an RF matching circuit.

[0019] The second switching module includes an analog switch and a capacitor. One end of the analog switch is inductively coupled to another lead of the ambient temperature sensor, and the other end of the analog switch is connected to an RC charge-discharge temperature measurement circuit.

[0020] When the shared I / O port is at the first level, the RF switch is closed and the analog switch is open, and the ambient temperature sensor lead is connected to the RF signal path; when the shared I / O port is at the second level, the RF switch is open and the analog switch is closed, and the ambient temperature sensor lead is connected to the temperature measurement circuit path.

[0021] By adopting the above technical solution, when the analog switch disconnects the RF path, the RC circuit accurately measures the resistance of the temperature sensor, improving the temperature measurement accuracy of the temperature sensor. The shared IO port reduces the chip pin occupation and simplifies the hardware.

[0022] In a preferred embodiment of this application: the ambient temperature sensor lead multiplexing method includes a dual-lead mode; in the dual-lead mode...

[0023] The time-division multiplexing circuit includes a balun that converts the two leads of the ambient temperature sensor into differential signals.

[0024] The first switch module and the second switch module are respectively coupled to the two output terminals of the balun;

[0025] The RC charge-discharge temperature measurement circuit calculates the temperature value based on the relationship between the fixed charging capacitor and the charge-discharge time constant.

[0026] By adopting the above technical solution, the dual-lead mode utilizes balun conversion differential signals to enhance anti-interference capability, and improves temperature measurement accuracy by calculating temperature values ​​based on fixed charging capacitors.

[0027] In a preferred embodiment of this application: the needle assembly further includes a metal needle and a battery soldered to the front end of the PCBA board; one of the temperature sensors is configured as a lead wire with the lead wire end soldered to the PCBA board and the probe end extending to the tip of the metal needle;

[0028] The PCBA board is provided with a metal spring that contacts the inner wall of the metal needle tube as a charging positive electrode;

[0029] The reduced-diameter section at the end of the PCBA board is inserted into the thin tube section of the coaxial coupling connection shaft, and a negative electrode spring is provided to connect the grounding terminal of the PCBA board to the inner wall of the thin tube section to form a charging circuit.

[0030] By adopting the above technical solution and combining the design of the positive and negative charging contacts, a stable power supply to the probe's internal circuitry is ensured, enabling long-term use in harsh environments such as high temperatures.

[0031] In a preferred embodiment of this application: the ceramic insulating ring is disposed at the junction of the metal needle tube and the coaxial coupling connection shaft via an outer ring groove. The inner cavity of the ceramic insulating ring is sealed, and the outer ring is provided with an adhesive groove to achieve insulation isolation between the metal needle tube and the inner conductor of the coaxial coupling connection shaft.

[0032] By adopting the above technical solution, the ceramic insulating ring achieves insulation isolation through the adhesive groove, effectively preventing the risk of short circuit between the inner and outer conductors.

[0033] In a preferred embodiment, this application further includes a ceramic handle, the inner diameter of which is adapted to the diameter of an ambient temperature sensor probe, the end of the ambient temperature sensor pin being in close contact with the inner wall of the ceramic handle to sense temperature; and a positioning groove at the bottom of the ceramic handle forming an interference fit with the end of the ambient temperature sensor pin.

[0034] By adopting the above technical solution, the ceramic handle not only provides good heat insulation, but also enhances the overall structural strength of the equipment by forming an interference fit with the ambient temperature sensor pin through the positioning groove.

[0035] In a preferred embodiment of this application, the coaxial coupling connection shaft includes:

[0036] Metal outer wall containing coaxial channels,

[0037] The annular groove and barb designed at the inner end cooperate with the glue storage groove on the outer wall of the ceramic handle to form a glue sealing cavity.

[0038] By adopting the above technical solution, the inner end design of the coaxial coupling connecting shaft is designed to cooperate with the outer wall of the ceramic handle to form a sealed cavity, which improves the waterproof and dustproof performance of the equipment.

[0039] In a preferred embodiment of this application: the PCBA board integrates multiple equally spaced surface-mount temperature sensors and is surrounded by a thermal pad; the outer surface of the ceramic insulating ring is provided with a depth warning marking ring; and the lead extension of the ambient temperature sensor serves as an antenna radiator.

[0040] By adopting the above technical solution, the surface-mount temperature sensors on the PCBA board are evenly distributed, and combined with the application of thermal pads, the uniformity and sensitivity of temperature sensing are ensured. The design of the antenna radiator further optimizes the transmission efficiency of wireless signals.

[0041] Secondly, the objective of this invention is achieved through the following technical solution:

[0042] A method for manufacturing a high-temperature wireless temperature probe includes the following steps:

[0043] Insert the PCBA board into the metal needle tube, positioning the lead wire temperature sensor probe end at the tip of the metal needle tube, with the positive electrode spring contacting the inner wall of the metal needle tube; wrap the PCBA board with a thermal pad.

[0044] The ceramic insulating ring is pressed and fitted sequentially with the end of the metal needle tube and the front end of the coaxial coupling connection shaft to form an insulating and sealing structure.

[0045] Insert the reduced diameter section of the PCBA into the thin tube section of the coaxial coupling connection shaft, so that the negative electrode spring abuts against the inner wall of the coaxial coupling connection shaft to form electrical conductivity; weld and fix the relative position of the coaxial coupling connection shaft and the PCBA board.

[0046] The lead extension of the ambient temperature sensor is inserted into the inner cavity of the coaxial coupling shaft and pressed tightly against the inner wall of the ceramic handle. Adhesive is applied to the mating surfaces of the coaxial coupling shaft and the ceramic handle, and curing forms a multi-layered sealing structure. By adopting this technical solution, the surface-mount temperature sensors on the PCBA board are evenly distributed, and combined with the application of thermal pads, this ensures uniformity and sensitivity in temperature sensing. The design of the antenna radiator further optimizes the transmission efficiency of the wireless signal.

[0047] In summary, the present application has the following beneficial technical effects:

[0048] The device achieves wireless transmission of temperature data in high-temperature environments through a combination of needle assembly, ceramic insulating ring, and coaxial coupling connection shaft. The integrated ambient temperature sensor leads and time-division multiplexing circuitry on the PCBA board enable the device to switch between radio frequency mode and temperature measurement mode, ensuring measurement accuracy and stability. Attached Figure Description

[0049] Figure 1 These are two different perspectives of the overall structure of a high-temperature wireless temperature probe based on NTC lead time-division multiplexing in one embodiment of this application;

[0050] Figure 2 This is an overall cross-sectional view of a high-temperature wireless temperature probe based on NTC lead time-division multiplexing in one embodiment of this application;

[0051] Figure 3 This is an exploded view of a high-temperature wireless temperature probe based on NTC lead time-division multiplexing in one embodiment of this application;

[0052] Figure 4 yes Figure 2 A magnified view of part A in the image;

[0053] Figure 5 This is a time-division multiplexing circuit diagram of a single-lead mode in a high-temperature wireless temperature probe based on NTC lead time-division multiplexing in one embodiment of this application;

[0054] Figure 6 This is a circuit diagram of a dual-lead mode time-division multiplexing circuit in a high-temperature wireless temperature probe based on NTC lead time-division multiplexing in one embodiment of this application.

[0055] Explanation of reference numerals in the attached figures:

[0056] 1. Needle assembly; 11. PCBA board; 111. Positive electrode spring; 112. Negative electrode spring; 12. Metal needle; 13. Battery; 14. Ambient temperature sensor lead wire; 2. Ceramic insulating ring; 21. Glue application groove; 22. Depth warning label ring; 3. Coaxial coupling connection shaft; 31. Thin tube section; 32. Annular groove; 33. Barb; 4. Ceramic handle; 41. Positioning groove; 42. Grip groove. Detailed Implementation

[0057] The following is in conjunction with the appendix Figures 1 to 6 This application will be described in further detail.

[0058] Example 1

[0059] In one embodiment, reference is made to Figures 1 to 3 This application discloses a high-temperature wireless temperature probe based on NTC lead time-division multiplexing. The high-temperature wireless temperature probe includes a needle tube assembly 1, a ceramic insulating ring 2, a coaxial coupling connection shaft 3, and a ceramic handle 4 connected in sequence.

[0060] Reference Figures 1 to 3 The needle assembly 1 includes a built-in PCBA board 11, a metal needle tube 12, and a battery 13 soldered to the front end of the PCBA board 11. The PCBA board 11 integrates an ambient temperature sensor lead 14, a time-division multiplexing circuit, and at least two temperature sensors. The lead of the ambient temperature sensor lead 14 extends from the metal needle tube 12 to the ceramic handle 4. In the application scenario of a food high-temperature wireless probe, the temperature sensor near the metal needle tube 12 is the food NTC, and the temperature sensor near the ceramic handle 4 is the ambient NTC. The extended section of the ambient temperature sensor lead 14 serves as an antenna radiator. The temperature sensor used as the food NTC is set in the form of a lead, with the lead end soldered to the PCBA board 11 and the probe end extending beyond the top of the battery 13, so that when the PCBA board 11 is inserted into the metal needle tube 12, the probe reaches the tip of the metal needle tube 12, which helps to improve the temperature measurement response speed of the food NTC.

[0061] PCBA board 11 has a metal spring contact that contacts the inner wall of the metal needle tube 12 as the positive charging electrode (when PCBA board 11 is inserted into the metal needle tube 12), also called positive electrode spring contact 111. The positive electrode spring contact 111 is located on the left and right sides of PCBA board 11. The tapered section at the end of PCBA board 11 is inserted into the thin tube section 31 of the coaxial coupling connecting shaft 3, and the tapered section at the end of PCBA board 11 has a negative electrode spring contact 112. The negative electrode spring contact 112 is used to connect the ground terminal of PCBA board 11 to the inner wall of the thin tube section 31 to form a charging circuit. PCBA board 11 integrates multiple equally spaced surface-mount temperature sensors (not shown in the figure) and is surrounded by a thermal pad. The thermal pad can be a silicone pad with high thermal conductivity or a phase change sheet material. Through the thermal pad, the temperature of the object being measured is quickly transferred from the metal needle tube 12 to the surface-mount temperature sensors on PCBA board 11.

[0062] Reference Figures 3 to 5 The RC charge / discharge temperature measurement circuit on PCBA board 11 calculates the temperature value based on the relationship between a fixed charging capacitor and the charge / discharge time constant. Specifically, the charge / discharge circuit of this application can control different temperature sensors through multiple I / O ports of the control unit to perform RC charge / discharge. By using the RC charge / discharge time constant τ=R×C, the charging time is calculated, the charging capacitor is fixed, and the resistance R of the temperature sensor at this time is inferred to obtain the corresponding temperature value. The high-precision clock enables the entire temperature measurement accuracy to reach ±0.3℃. Unlike conventional ADC temperature measurement circuits, this reduces the resource requirements of the chip. It does not require a high-precision ADC; only a high-precision clock for the system is needed. High-precision clock chips are cheaper than high-precision ADC chips.

[0063] Reference Figure 2 and Figure 3The coaxial coupling connecting shaft 3 includes a metal outer wall containing a coaxial channel, a metal inner conductor forming a coaxial transmission structure with the ambient temperature sensor lead 14, and an annular groove 32 and a barb 33 designed at the end. The coaxial coupling connecting shaft 3 and the ambient temperature sensor lead 14 form a coaxial transmission line. The ambient temperature sensor lead 14 is wrapped with a high-temperature resistant insulating layer to avoid short circuits with the metal needle tube 12 and suppress radiation from the metal needle tube 12. The coaxial coupling connecting shaft 3 is a metal connecting shaft, and the metal outer wall forms a radio frequency signal ground. The annular groove 32 and the barb 33 designed at the end of the coaxial coupling connecting shaft 3 cooperate with the glue storage groove on the outer wall of the ceramic handle 4 to form a glue sealing cavity. When connecting, glue can be applied to strengthen the connection and prevent glue from flowing into the inner tube of the coaxial coupling connecting shaft 3. The coaxial coupling shaft 3 of this application has a very small internal diameter, which makes it easy to apply glue to the part in contact with the PCBA board 11 to form a seal, thus sealing and isolating the entire PCBA board 11 from the coaxial coupling shaft 3 above. This prevents water from entering the lower part of the PCBA board 11 even if the upper part gets wet, thus reducing the need for waterproofing the PCBA part.

[0064] Reference Figure 3 and Figure 4 The ceramic insulating ring 2 is located at the junction of the metal needle tube 12 and the coaxial coupling shaft 3 via an outer ring groove. The inner cavity of the ceramic insulating ring 2 is sealed, forming a closed cavity during assembly. The outer ring has an adhesive application groove 21 to achieve insulation isolation between the inner conductors of the metal needle tube 12 and the coaxial coupling shaft 3. Adhesive is applied to the adhesive application groove 21 during connection to improve the sealing of the connection. The outer surface of the ceramic insulating ring 2 has a depth warning ring 22, which can be a clearly visible black ring. The ceramic insulating ring 2 is used to insulate and isolate the metal needle tube 12 and the coaxial coupling shaft 3, preventing radio frequency short circuits and short circuits in the positive and negative circuits.

[0065] Reference Figure 2 and Figure 3 The inner diameter of the ceramic handle 4 is matched with the diameter of the ambient temperature sensor probe, avoiding excessive air accumulation inside the cavity and improving the sealing effect of the entire high-temperature wireless probe. The end of the ambient temperature sensor pin is in close contact with the inner wall of the ceramic handle 4 to sense temperature. The bottom of the ceramic handle 4 has a positioning groove 41 that forms an interference fit with the end of the ambient temperature sensor pin. The ceramic handle 4 and the coaxial coupling connection shaft 3 are designed with a tight fit structure. The ceramic handle 4 is designed with multiple loop grooves for storing adhesive to increase connection strength. The outer wall of the ceramic handle 4 is also provided with a grip groove 42, which allows the user to easily grip the ceramic handle 4.

[0066] Reference Figure 5 ,by Figure 5Taking the circuit diagram shown as an example, the time-division multiplexing circuit selectively connects to the RF transceiver circuit or the RC charge / discharge temperature measurement circuit; the time-division multiplexing circuit includes a first switch module, a second switch module, and a control unit. The first switch module controls the connection and disconnection between the RF matching circuit and the ambient temperature sensor lead 14; the second switch module controls the connection and disconnection between the temperature measurement circuit and the ambient temperature sensor lead 14; the control unit coordinates the timing actions of the first switch module and the second switch module; the first switch module and the second switch module switch between RF mode and temperature measurement mode through the common IO port of the control unit.

[0067] Specifically, the ambient temperature sensor lead 14 is multiplexed in a single-lead mode. In single-lead mode, the first switch module includes an RF switch and a capacitor C2. One end of the RF switch is coupled to one lead of the ambient temperature sensor through the capacitor, and the other end is coupled to the control unit through an RF matching circuit. The control unit includes a wireless transmitter chip. The antenna feed point of the wireless transmitter chip is connected to the RF switch through the RF matching circuit. The second switch module includes an analog switch and a capacitor. One end of the analog switch is coupled to the other lead of the ambient temperature sensor through an inductor, and the other end of the analog switch is connected to an RC charging and discharging temperature measurement circuit. When the shared IO port (VCTL_IO port in the figure) is at the first level, the RF switch is closed and the analog switch is open, and the ambient temperature sensor lead 14 is connected to the RF signal path. The first level is low. When the shared IO port is at the second level (high level), the RF switch is open and the analog switch is closed.

[0068] During the temperature measurement phase: Ambient temperature sensor lead 14 is connected to the temperature measurement circuit path. At this time, the ambient temperature sensor can measure the temperature, and simultaneously, the RC_IO port outputs 0, which is equivalent to grounding, releasing the charge of capacitor C2 on the RF circuit to avoid affecting the temperature measurement. After the release is complete, the timer is started, and the RC_IO port is pulled high to charge the ambient temperature sensor and capacitor C1. Since the RF switch is off, capacitor C2 does not form a circuit, so it is not charged at this time and does not affect the charging circuit. When the charge of RC charging and discharging capacitor C1 reaches a certain value, it meets the interrupt voltage of the Interupt_IO port, generating an interrupt. At this time, the timer is stopped, and the time at this moment is calculated as the charging time, which is converted into the corresponding temperature. After the measurement is completed, the RC_IO port and Interupt_IO are immediately pulled low to release the charge of RC charging and discharging capacitor C1. After the release is complete, RC_IO and Interupt_IO are set to open-drain output, and then the RF phase begins. This time-division operation only switches between time-division modes when the ambient temperature sensor is working; it does not affect the temperature measurement of other temperature sensors.

[0069] During the radio frequency (RF) phase, the RF switch is closed and the analog switch is open. At this time, the RF circuit of the wireless transmitter chip is connected to the ambient temperature sensor lead 14, and the RF circuit is turned on. The wireless communication data is transmitted through the ambient temperature sensor lead 14 as an antenna.

[0070] Example 2

[0071] Reference Figure 6 ,by Figure 6 Taking the circuit diagram shown as an example, the difference between this embodiment and embodiment 1 is that the multiplexing method of the ambient temperature sensor lead 14 includes a dual-lead mode. In the dual-lead mode, the time-division multiplexing circuit includes a balun, which converts the two leads of the ambient temperature sensor into differential signals; that is, a single lead is divided into differential leads through a balun, and the antennas of the two ambient temperature sensors are used as antennas, turning the antennas into differential leads.

[0072] The RF switch and analog switch are respectively coupled to the two output terminals of the balun; after isolating the DC component through a capacitor, they are connected to the two leads of the ambient temperature sensor. One lead is connected to the RC charging and discharging temperature measurement circuit through an inductor, and the other ambient temperature sensor lead 14 is connected to an inductor through an analog switch and then to the RC temperature measurement circuit.

[0073] During the radio frequency (RF) phase: When the VCTL_IO port is low, the RF switch is closed and the analog switch is open. At this time, the RF circuit for wireless transmission is connected to the ambient temperature sensor lead 14. The RF circuit is then activated, and wireless communication data can be transmitted through the antenna.

[0074] During the temperature measurement phase: VCTL_IO port is high, the RF switch is open, and the analog switch is closed. At this time, the RF circuit for wireless transmission is disconnected from lead 14 of the ambient temperature sensor, the RF circuit is disconnected, and the ambient temperature sensor is connected to the temperature measurement circuit. The ambient NTC can then measure the temperature. Simultaneously, when the software measures the ambient NTC temperature, it controls RC_IO port to output 0, which is equivalent to grounding, releasing the charge on capacitor C2 in the RF circuit to avoid affecting the temperature measurement. After the charge is released, timing begins, and RC_IO port is pulled high to charge the ambient temperature sensor and capacitor C1. Because the RF switch is open, capacitor C2 does not form a circuit and therefore will not be charged. When the charge on capacitor C1 reaches a certain value, it satisfies the interrupt voltage of Interupt_IO port, generating an interrupt. At this time, timing stops, and the timing time is the charging time, from which the corresponding temperature is calculated. After the measurement is complete, RC_IO port and Interupt_IO are immediately pulled low to release the charge on capacitor C1. After the release, RC_IO and Interupt_IO are set to open-drain output.

[0075] In another embodiment, this application also discloses a method for manufacturing a high-temperature wireless temperature probe, which specifically includes the following steps:

[0076] S1: Insert PCBA board 11 into metal needle tube 12, so that the probe end of lead wire temperature sensor is positioned at the tip of metal needle tube 12, and positive electrode spring 111 contacts the inner wall of metal needle tube 12; PCBA board 11 is wrapped with thermal pad.

[0077] In this embodiment, a prefabricated PCBA board 11 is inserted into the metal needle tube 12, ensuring that the probe end of the lead-wire temperature sensor is at the tip of the metal needle tube 12. The metal springs (i.e., positive electrode springs 111) on both sides of the PCBA board 11 are in close contact with the inner wall of the metal needle tube 12 to form a charging positive electrode circuit. A silicone pad or phase change sheet material with high thermal conductivity is wrapped around the PCBA board 11 as a thermal pad, and the axial position of the PCBA board 11 in the metal needle tube 12 is fixed by dispensing adhesive.

[0078] S2: The ceramic insulating ring 2 is pressed and fitted together with the end of the metal needle tube 12 and the front end of the coaxial coupling connecting shaft 3 in sequence, and cured to form an insulating and sealed structure.

[0079] In this embodiment, high-temperature resistant sealant is uniformly coated in the annular groove 32 on the outer surface of the ceramic insulating ring 2; one end of the ceramic insulating ring 2 is tightly pressed and fitted with the end of the metal needle tube 12, and the other end is tightly pressed and fitted with the front end of the coaxial coupling connecting shaft 3. After assembly, the black depth warning indicator ring 22 of the ceramic insulating ring 2 is displayed at the joint. Therefore, when using it, it can remind the user to measure the temperature of food that has submerged the food above the depth warning indicator ring 22, thus achieving a foolproof reminder effect.

[0080] Specifically, after the ceramic insulating ring 2 is cured at high temperature, it forms an insulating isolation layer and an airtight sealing structure, while simultaneously achieving radio frequency short-circuit protection between the metal needle tube 12 and the coaxial coupling connection shaft 3.

[0081] S3: Insert the reduced diameter section of the PCBA into the thin tube section 31 of the coaxial coupling connecting shaft 3, so that the negative electrode spring 112 abuts against the inner wall of the coaxial coupling connecting shaft 3 to form electrical conduction; weld and fix the relative position of the coaxial coupling connecting shaft 3 and the PCBA board 11.

[0082] In this embodiment, the multiple sealing structure of the ceramic insulating ring 2 and the barb 33 of the coaxial coupling connecting shaft 3 can solve the problems of high-temperature airtightness and production yield.

[0083] Specifically, the reduced diameter section at the end of the PCBA board 11 is inserted into the thin tube section 31 of the coaxial coupling connecting shaft 3; ensuring that the negative electrode spring 112 at the end of the PCBA board 11 is in close contact with the inner wall of the thin tube of the coaxial coupling connecting shaft 3 to form a charging negative electrode circuit; and using laser spot welding process to fix the relative position of the coaxial coupling connecting shaft 3 and the PCBA board 11.

[0084] S4: Insert the extension of the ambient temperature sensor lead 14 into the inner cavity of the coaxial coupling connecting shaft 3 and press it against the inner wall of the ceramic handle 4. Apply adhesive to the mounting surface of the coaxial coupling connecting shaft 3 and the ceramic handle 4 and cure to form a multi-seal structure.

[0085] In this embodiment, the extension of the ambient temperature sensor lead 14 is used as the antenna radiator.

[0086] Specifically, the lead extension of the ambient temperature sensor passes through the inner cavity of the coaxial coupling connecting shaft 3; the end of the lead is in close contact with the inner wall of the ceramic handle 4 to realize the temperature sensing function; sealant is applied to the annular groove 32 of the coaxial coupling connecting shaft 3 and the mounting surface of the ceramic handle 4; after curing, a multi-layer sealing and protection structure is formed at the joint between the coaxial coupling connecting shaft 3 and the ceramic handle 4, and the barb 33 structure of the coaxial coupling connecting shaft 3 prevents the glue from seeping into the coaxial channel.

[0087] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0088] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0089] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A high-temperature wireless temperature probe based on NTC lead time-division multiplexing, characterized in that, include: A needle assembly (1), a ceramic insulating ring (2), and a coaxial coupling connecting shaft (3) are connected in sequence; the needle assembly (1) has a built-in PCBA board (11), and the PCBA board (11) integrates: Ambient temperature sensor lead (14), Time-division multiplexing circuit, selectively connected to RF transceiver circuit or RC charge / discharge temperature measurement circuit; At least two temperature sensors; the ceramic insulating ring (2) is disposed at the junction of the needle assembly (1) and the coaxial coupling connecting shaft (3), forming a sealed cavity inside; The coaxial coupling connection shaft (3) includes: The outer metal wall forms the radio frequency signal ground and the inner metal conductor forms a coaxial transmission structure with the lead wire (14) of the ambient temperature sensor; The time-division multiplexing circuit includes: The first switching module controls the connection and disconnection between the radio frequency matching circuit and the ambient temperature sensor lead (14); The second switch module controls the connection and disconnection between the temperature measuring circuit and the lead (14) of the ambient temperature sensor; The control unit coordinates the timing actions of the first switch module and the second switch module; the first switch module and the second switch module switch between radio frequency mode and temperature measurement mode through the common I / O port of the control unit. The needle assembly (1) also includes a metal needle (12) and a battery (13) soldered to the front end of the PCBA board (11); one of the temperature sensors is configured as a lead wire with the lead wire end soldered to the PCBA board (11) and the probe end extending to the tip of the metal needle (12). The PCBA board (11) is provided with a metal spring sheet that contacts the inner wall of the metal needle tube (12) as a charging positive electrode; The reduced diameter section (113) at the end of the PCBA board (11) is inserted into the thin tube section (31) of the coaxial coupling connecting shaft (3), and a negative electrode spring (112) is provided to connect the grounding end of the PCBA board (11) to the inner wall of the thin tube section (31) to form a charging circuit. The ceramic insulating ring (2) is located at the junction of the metal needle tube (12) and the coaxial coupling connection shaft (3) through an outer ring groove. The inner cavity of the ceramic insulating ring (2) is sealed, and the outer ring is provided with an adhesive groove (21) to achieve insulation isolation between the metal needle tube (12) and the inner conductor of the coaxial coupling connection shaft (3).

2. The high-temperature wireless temperature probe based on NTC lead time-division multiplexing according to claim 1, characterized in that, The ambient temperature sensor lead (14) can be reused in a single-lead mode. In the single-lead mode, The first switching module includes an RF switch and a capacitor. One end of the RF switch is coupled to a lead of the ambient temperature sensor through the capacitor, and the other end is coupled to the control unit through an RF matching circuit. The second switching module includes an analog switch and a capacitor. One end of the analog switch is inductively coupled to another lead of the ambient temperature sensor, and the other end of the analog switch is connected to an RC charge-discharge temperature measurement circuit. When the shared IO port is at the first level, the RF switch is closed and the analog switch is open, and the ambient temperature sensor lead (14) is connected to the RF signal path; When the shared IO port is at the second level, the RF switch is open and the analog switch is closed, and the ambient temperature sensor lead (14) is connected to the temperature measurement circuit path.

3. The high-temperature wireless temperature probe based on NTC lead time-division multiplexing according to claim 1, characterized in that, The ambient temperature sensor lead (14) can be reused in a dual-lead mode. In the dual-lead mode, The time-division multiplexing circuit includes a balun that converts the two leads of the ambient temperature sensor into differential signals. The first switch module and the second switch module are respectively coupled to the two output terminals of the balun; The RC charge-discharge temperature measurement circuit calculates the temperature value based on the relationship between the fixed charging capacitor and the charge-discharge time constant.

4. The high-temperature wireless temperature probe based on NTC lead time-division multiplexing according to claim 1, characterized in that, It also includes a ceramic handle (4), the inner diameter of which is adapted to the diameter of the ambient temperature sensor probe, and the end of the ambient temperature sensor pin is in close contact with the inner wall of the ceramic handle (4) to sense the temperature; the bottom of the ceramic handle (4) is set with a positioning groove (41) to form an interference fit with the end of the ambient temperature sensor pin.

5. The high-temperature wireless temperature probe based on NTC lead time-division multiplexing according to claim 4, characterized in that, The coaxial coupling connection shaft (3) includes: Metal outer wall containing coaxial channels, The annular groove (32) designed at the inner end and the barb (33) cooperate with the glue storage groove on the outer wall of the ceramic handle (4) to form a glue sealing cavity.

6. The high-temperature wireless temperature probe based on NTC lead time-division multiplexing according to claim 4, characterized in that, The PCBA board (11) integrates multiple equally spaced surface-mount temperature sensors and is surrounded by a thermal pad; the outer surface of the ceramic insulating ring (2) is provided with a depth warning mark ring (22); the extension of the ambient temperature sensor lead (14) serves as an antenna radiator.

7. A method for manufacturing a high-temperature wireless temperature probe, applied to the high-temperature wireless temperature probe based on NTC lead time-division multiplexing as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Insert the PCBA board (11) into the metal needle tube (12) so that the probe end of the lead wire temperature sensor is positioned at the tip of the metal needle tube (12) and the positive electrode spring (111) contacts the inner wall of the metal needle tube (12); the PCBA board (11) is wrapped with a thermal pad. The ceramic insulating ring (2) is pressed and fitted together with the end of the metal needle tube (12) and the front end of the coaxial coupling connecting shaft (3) in sequence, and cured to form an insulating and sealing structure; Insert the reduced diameter section (113) of the PCBA into the thin tube section (31) of the coaxial coupling connecting shaft (3), so that the negative electrode spring (112) abuts against the inner wall of the coaxial coupling connecting shaft (3) to form electrical conduction; weld and fix the relative position of the coaxial coupling connecting shaft (3) and the PCBA board (11); Insert the extension of the ambient temperature sensor lead (14) into the inner cavity of the coaxial coupling connecting shaft (3) and press it against the inner wall of the ceramic handle (4). Apply adhesive to the mounting surface of the coaxial coupling connecting shaft (3) and the ceramic handle (4) and cure to form a multi-seal structure.

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