High-temperature wireless temperature probe based on NTC (Negative Temperature Coefficient) lead time division multiplexing and manufacturing method

Abstract

The invention discloses a high-temperature wireless temperature probe based on NTC lead time division multiplexing and a manufacturing method, and relates to the technical field of wireless temperature probes, and the high-temperature wireless temperature probe comprises a needle tube assembly, a ceramic insulating ring and a coaxial coupling connecting shaft which are connected in sequence; a PCBA board is arranged in the needle tube assembly, and an environment temperature sensor lead and a time division multiplexing circuit are integrated on the PCBA board and selectively connected with the radio frequency receiving and transmitting circuit or the RC charging and discharging temperature measuring circuit. At least two temperature sensors; the ceramic insulating ring is arranged at the joint part of the needle tube assembly and the coaxial coupling connecting shaft, and an inner cavity forms a closed cavity; the coaxial coupling connection shaft comprises a metal outer wall which forms a radio frequency signal ground and a metal inner conductor which forms a coaxial transmission structure with an environment temperature sensor lead. According to the high-temperature wireless temperature probe, mutual interference between the radio frequency function and the temperature sensing function of the wireless temperature probe is effectively eliminated, and the high-temperature wireless temperature probe with high-precision temperature measurement performance is provided.

Description

Technical Field

[0001] The present application relates to the technical field of wireless temperature probes, and in particular to a high-temperature wireless temperature probe based on NTC lead time-sharing multiplexing and a manufacturing method thereof. Background Art

[0002] Wireless temperature probes are currently used in scenarios such as food temperature measurement. Existing wireless temperature probes often utilize a single NTC lead wire that doubles as an antenna (e.g., US12196619B2). However, this approach has significant drawbacks: when the RF signal is coupled to the temperature sensor through the lead wire, high-frequency noise can severely interfere with temperature measurement accuracy, resulting in temperature errors as high as ±1.5°. This issue stems from the lack of effective isolation between the physical connection of the lead wire between the RF mode and the temperature measurement mode, as well as the lack of shielding against electromagnetic interference. While existing solutions attempt to reduce costs through hardware reuse, the core issue lies in the mutual interference between the RF and temperature sensing functions, creating a technical bottleneck that restricts high-precision temperature measurement performance. Summary of the Invention

[0003] In order to address the deficiencies of the prior art, effectively eliminate the mutual interference between the radio frequency function and the temperature sensing function of the wireless temperature probe, and provide a high-temperature wireless temperature probe with high-precision temperature measurement performance, the present application provides a high-temperature wireless temperature probe based on NTC lead time-sharing multiplexing and a manufacturing method.

[0004] In the first aspect, the invention objectives of this application are achieved by adopting the following technical solutions: A high-temperature wireless temperature probe based on time-sharing multiplexing of NTC leads includes: a needle-tube assembly, a ceramic insulating ring, and a coaxial coupling connecting shaft connected in sequence; the needle-tube assembly has a built-in PCBA board, and the PCBA board integrates: Ambient temperature sensor leads, Time-sharing multiplexing circuit, selectively connected to the radio frequency transceiver circuit or the RC charge-discharge temperature measurement circuit; At least two temperature sensors; the ceramic insulating ring is arranged at the junction of the needle tube assembly and the coaxial coupling connecting shaft, and the inner cavity forms a closed cavity; The coaxial coupling connecting shaft comprises: The metal outer wall forms a radio frequency signal ground and forms a metal inner conductor of a coaxial transmission structure with the ambient temperature sensor lead.

[0005] By adopting the above technical solution, radio frequency communication and temperature measurement are non-interfering with each other based on a time-sharing multiplexing circuit. By time-sharing multiplexing the leads of the ambient temperature sensor into an 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, the thermal expansion compensation design of the ceramic ring and the coaxial shielding characteristics of the metal connecting shaft are used to solve the problems of structural cracking and sealing failure in high-temperature environments, reduce the overall volume, and improve the production yield.

[0006] In a preferred embodiment of the present application, the time-division multiplexing circuit includes: A first switch module controls the connection and disconnection of the radio frequency matching circuit and the ambient temperature sensor lead; A second switch module controls the on / off of the temperature measurement circuit and the ambient temperature sensor lead; 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 are switched between the radio frequency mode and the temperature measurement mode through the common IO port of the control unit.

[0007] 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.

[0008] In a preferred example of the present application: the ambient temperature sensor lead multiplexing mode includes a single lead mode. In the single lead mode, The first switch module includes a radio frequency switch and a capacitor, one end of the radio frequency switch is coupled to a lead of the ambient temperature sensor via the capacitor, and the other end is coupled to the control unit via a radio frequency 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 the RC charge-discharge temperature measurement circuit. When the common IO port is at a first level, the RF switch is closed and the analog switch is opened, and the ambient temperature sensor lead is connected to the RF signal path; when the common IO port is at a second level, the RF switch is opened and the analog switch is closed, and the ambient temperature sensor lead is connected to the temperature measurement circuit path.

[0009] 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, thereby improving the temperature measurement accuracy of the temperature sensor. The shared IO port reduces the chip pin occupancy and realizes hardware simplification.

[0010] In a preferred example of the present application: the ambient temperature sensor lead multiplexing method 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 a differential signal; 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 capacitance and the charge-discharge time constant.

[0011] By adopting the above technical solution, the dual-lead mode uses a balun to convert the differential signal, which enhances the anti-interference ability, and calculates the temperature value based on the fixed charging capacitor, thereby improving the temperature measurement accuracy.

[0012] In a preferred embodiment of the present application, the needle tube assembly further comprises a metal needle tube and a battery welded to the front end of the PCBA board; one of the temperature sensors is provided in the form of a lead, the lead end is welded to the PCBA board, and the probe end extends to the tip of the metal needle tube; The PCBA board is provided with a metal spring that contacts the inner wall of the metal needle tube as a charging positive electrode; The reduced diameter section at the end of the PCBA board is inserted into the thin tube section of the coaxial coupling connecting shaft, and a negative spring is provided to connect the ground end of the PCBA board and the inner wall of the thin tube section to form a charging circuit.

[0013] By adopting the above technical solution and combining it with the design of the positive and negative charging springs, the stable power supply of the internal circuit of the probe is ensured, making it suitable for long-term use in harsh environments such as high temperature.

[0014] In a preferred example of the present application: the ceramic insulating ring is arranged at the junction of the metal needle tube and the coaxial coupling connecting shaft through an outer ring groove, the inner cavity of the ceramic insulating ring is sealed, and the outer ring is provided with a glue coating groove to achieve insulation isolation between the metal needle tube and the inner conductor of the coaxial coupling connecting shaft.

[0015] By adopting the above technical solution, the ceramic insulating ring achieves insulation isolation through the glue-coated slots, effectively preventing the risk of short circuit between the inner and outer conductors.

[0016] In a preferred example, the present application further includes a ceramic handle, the inner cavity diameter of the ceramic handle is adapted to the diameter of the ambient temperature sensor probe, and the end of the ambient temperature sensor pin is close to the inner wall of the ceramic handle to sense the temperature; the bottom of the ceramic handle is provided with a positioning groove that forms an interference fit with the end of the ambient temperature sensor pin.

[0017] By adopting the above technical solution, the ceramic handle not only provides good heat insulation effect, but also forms an interference fit with the ambient temperature sensor pin through the positioning groove, thereby enhancing the overall structural strength of the equipment.

[0018] In a preferred embodiment of the present application, the coaxial coupling connecting shaft includes: The metal outer wall contains the coaxial channel. The annular groove and the 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.

[0019] By adopting the above technical solution, the inner end design of the coaxial coupling connecting shaft cooperates with the outer wall of the ceramic handle to form a sealed cavity, thereby improving the waterproof and dustproof performance of the equipment.

[0020] In a preferred example of the present application: the PCBA board integrates multiple equidistantly distributed patch temperature sensors inside and is wrapped with a thermal pad on the outside; the outer surface of the ceramic insulation ring is provided with a depth warning marking ring; the extended section of the ambient temperature sensor lead serves as an antenna radiator.

[0021] By adopting this technical solution, the chip temperature sensors on the PCBA are evenly spaced. Combined with the use of thermal pads, this ensures uniform and sensitive temperature sensing. The design of the antenna radiator further optimizes the transmission efficiency of wireless signals.

[0022] In the second aspect, the invention objective of this application is achieved by adopting the following technical solutions: A method for manufacturing a high-temperature wireless temperature probe comprises the following steps: Insert the PCBA into the metal needle tube, position the lead temperature sensor probe end to the tip of the metal needle tube, and make sure the positive spring contacts the inner wall of the metal needle tube; wrap the PCBA with the thermal pad. The ceramic insulating ring is tightly fitted and pressed with the end of the metal needle tube and the front end of the coaxial coupling connecting shaft in sequence, and solidified to form an insulating sealing structure; Insert the reduced diameter section of the PCBA into the thin tube section of the coaxial coupling shaft so that the negative electrode spring contacts the inner wall of the coaxial coupling shaft to achieve electrical conduction; weld and fix the relative positions of the coaxial coupling shaft and the PCBA board; The extended lead of the ambient temperature sensor is inserted into the inner cavity of the coaxial coupling shaft and placed against the inner wall of the ceramic handle. Glue is applied to the mating surface of the coaxial coupling shaft and the ceramic handle and cured to form a multi-seal structure. This technical solution ensures that the chip temperature sensors on the PCBA are evenly spaced. Combined with the use of thermal pads, this ensures uniform and sensitive temperature sensing. The design of the antenna radiator further optimizes the transmission efficiency of the wireless signal.

[0023] In summary, this application has the following beneficial technical effects: The combined design of a needle-tube assembly, ceramic insulating ring, and coaxial coupling shaft enables wireless transmission of temperature measurements in high-temperature environments. The integrated ambient temperature sensor leads and time-division multiplexing circuit on the PCBA board enable the device to switch between RF mode and temperature measurement mode, ensuring measurement accuracy and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an overall structural diagram from two different perspectives of a high-temperature wireless temperature probe based on time-sharing multiplexing of NTC leads in one embodiment of the present application; Figure 2 This is an overall cross-sectional view of a high-temperature wireless temperature probe based on time-sharing multiplexing of NTC leads in one embodiment of the present application; Figure 3 This is an exploded view of a high-temperature wireless temperature probe based on time-sharing multiplexing of NTC leads in one embodiment of the present application; Figure 4 yes Figure 2 A partial enlarged view of middle A; Figure 5 This is a time-sharing multiplexing circuit diagram of a single-lead mode in a high-temperature wireless temperature probe based on NTC lead time-sharing multiplexing in one embodiment of the present application; Figure 6 This is a time-sharing multiplexing circuit diagram of a dual-lead mode in a high-temperature wireless temperature probe based on NTC lead time-sharing multiplexing in one embodiment of the present application.

[0025] Description of reference numerals: 1. Needle tube assembly; 11. PCBA board; 111. Positive electrode spring; 112. Negative electrode spring; 12. Metal needle tube; 13. Battery; 14. Ambient temperature sensor lead; 2. Ceramic insulating ring; 21. Glue coating slot; 22. Depth warning mark ring; 3. Coaxial coupling connecting shaft; 31. Thin tube section; 32. Annular groove; 33. Barb; 4. Ceramic handle; 41. Positioning slot; 42. Gripping slot. DETAILED DESCRIPTION

[0026] The following is combined with Figures 1 to 6 This application is described in further detail.

[0027] Example 1 In one embodiment, referring to Figures 1 to 3 The present application discloses a high-temperature wireless temperature probe based on time-sharing multiplexing of NTC leads. The high-temperature wireless temperature probe includes a needle tube assembly 1, a ceramic insulating ring 2, a coaxial coupling connecting shaft 3 and a ceramic handle 4 connected in sequence.

[0028] Reference Figures 1 to 3The needle tube assembly 1 includes a built-in PCBA board 11, a metal needle tube 12, and a battery 13 welded to the front end of the PCBA board 11. The PCBA board 11 is integrated with an ambient temperature sensor lead 14, a time-sharing 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 the food high-temperature wireless probe, the temperature sensor close to the metal needle tube 12 is the food NTC, and the temperature sensor close to 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, the lead end is welded to the PCBA board 11, and the probe end passes over 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 is beneficial to improving the temperature measurement response speed of the food NTC.

[0029] The PCBA board 11 is equipped with a metal spring that contacts the inner wall of the metal needle tube 12, serving as the positive charging electrode (when the PCBA board 11 is inserted into the metal needle tube 12). This spring, also known as the positive spring 111, is located on both sides of the PCBA board 11. 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. A negative spring 112 is also located at the reduced diameter section of the PCBA board 11. This connects the ground terminal of the PCBA board 11 to the inner wall of the thin tube section 31, forming a charging circuit. The PCBA board 11 integrates multiple evenly spaced surface mount temperature sensors (not shown) and is surrounded by a thermal pad. The thermal pad can be made of high-thermal-conductivity silicone or phase-change material. This thermal pad allows the temperature of the object being measured to be quickly transferred from the metal needle tube 12 to the surface mount temperature sensors on the PCBA board 11.

[0030] Reference Figures 3 to 5 The RC charge-discharge temperature measurement circuit on the PCBA board 11 calculates the temperature value based on the relationship between the fixed charging capacitor and the charging and discharging time constant. Specifically, the charge-discharge circuit of the present application can control the RC charging and discharging of different temperature sensors at multiple IO ports of the control unit. 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 reversed to obtain the corresponding temperature value. The high-precision clock can make the entire temperature measurement accuracy reach ±0.3°C. Different from the conventional ADC temperature measurement circuit, it reduces the resource requirements for the chip. It does not require a high-precision ADC, but only a high-precision clock for the system. The price of a high-precision clock chip is lower than that of a high-precision ADC chip.

[0031] Reference Figure 2 and Figure 3The coaxial coupling connecting shaft 3 includes a metal outer wall containing a coaxial channel, a metal inner conductor that forms 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 lead of the ambient temperature sensor form a coaxial transmission line. The ambient temperature sensor lead 14 is wrapped with a high-temperature resistant insulation layer to avoid contact and short circuit with the metal needle tube 12, thereby suppressing the radiation of the metal needle tube 12. The coaxial coupling connecting shaft 3 is a metal connecting shaft, and the metal outer wall forms the 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 chamber. When the glue sealing chamber is connected, 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 internal diameter of the coaxial coupling connecting shaft 3 of the present application is very small, so that the part in contact with the PCBA board 11 can be simply glued to form a seal, thereby sealing and isolating the entire PCBA board 11 from the coaxial coupling connecting shaft 3 above. Even if water enters the upper part, it will not enter the lower part of the PCBA board 11, thereby reducing the waterproof process of the PCBA part.

[0032] Reference Figure 3 and Figure 4 The ceramic insulating ring 2 is arranged at the junction of the metal needle tube 12 and the coaxial coupling connecting shaft 3 through the outer ring groove. The inner cavity of the ceramic insulating ring 2 is sealed. The inner cavity of the ceramic insulating ring 2 forms a closed cavity during assembly, and the outer ring is provided with a glue coating groove 21 to achieve insulation isolation between the metal needle tube 12 and the inner conductor of the coaxial coupling connecting shaft 3. Glue is applied to the glue coating groove 21 during connection to improve the sealing of the connection part. A depth warning identification ring 22 is provided on the outer surface of the ceramic insulating ring 2, such as a conspicuous black ring. The ceramic insulating ring 2 is used to insulate and isolate the metal needle tube 12 from the coaxial coupling connecting shaft 3 to prevent radio frequency short circuit and positive and negative circuit short circuit.

[0033] Reference Figure 2 and Figure 3 The inner diameter of the ceramic handle 4 is adapted to the diameter of the ambient temperature sensor probe to avoid too much air in the inner cavity, which is conducive to improving the sealing effect of the entire high-temperature wireless probe; the end of the ambient temperature sensor pin is close to the inner wall of the ceramic handle 4 to sense the temperature; the positioning groove 41 set at the bottom of the ceramic handle 4 forms an interference fit with the end of the ambient temperature sensor pin. The ceramic handle 4 and the coaxial coupling connecting shaft 3 are designed as a tight fit structure. The ceramic handle 4 is designed with multiple loop grooves for storing glue to increase the connection strength; the outer wall of the ceramic handle 4 is also provided with a gripping groove 42, which is convenient for people to pinch the ceramic handle 4 through the gripping groove 42.

[0034] Reference Figure 5 ,by Figure 5Taking the circuit diagram shown as an example, the time-sharing multiplexing circuit selectively connects the RF transceiver circuit or the RC charge and discharge temperature measurement circuit; the time-sharing multiplexing circuit includes a first switch module, a second switch module and a control unit, the first switch module controls the on-off of the RF matching circuit and the ambient temperature sensor lead 14; the second switch module controls the on-off of 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 are switched between the RF mode and the temperature measurement mode through the common IO port of the control unit.

[0035] Specifically, the multiplexing mode for the ambient temperature sensor lead 14 includes 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 via the capacitor, and the other end is coupled to the control unit via 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 via 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 via the inductor, and the other end of the analog switch is connected to the RC charge-discharge temperature measurement circuit. When the shared IO port (VCTL_IO port in the figure) is at a first level, the RF switch is closed and the analog switch is open, connecting the ambient temperature sensor lead 14 to the RF signal path, and the first level is low. When the shared IO port is at a second level (high), the RF switch is open and the analog switch is closed.

[0036] During the temperature measurement phase: the 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 at the same time, the RC_IO port is controlled to output 0, which is equivalent to grounding, releasing the charge of the C2 capacitor on the RF circuit to avoid affecting the temperature measurement. After the release is completed, the timing is turned on, and the RC_IO port is controlled to be pulled high at the same time to charge the ambient temperature sensor and capacitor C1. Since the RF switch is disconnected, capacitor C2 does not form a loop, so capacitor C2 is not charged at this time, and the charging circuit is not affected. When the charge of the RC charging and discharging capacitor C1 reaches a certain value, it meets the interrupt voltage of the Interupt_IO port, and an interrupt is generated. At this time, the timing is turned off, and the time at this time is calculated as the charging time, and the corresponding temperature is converted; immediately after the measurement, the RC_IO port and Interupt_IO are pulled low at the same time to release the charge of the RC charging and discharging capacitor C1. After the release is completed, RC_IO and Interupt_IO are set to open-drain output, and then the RF phase is entered. This time-sharing operation is only switched when the ambient temperature sensor is working, and the temperature measurement of other temperature sensors is not affected.

[0037] In the RF stage, the RF switch is closed and the analog switch is opened. At this time, the RF circuit of the wireless transmitter chip is connected to the ambient temperature sensor lead 14. At this time, the RF circuit is connected, and the wireless communication data is transmitted through the ambient temperature sensor lead 14 as an antenna.

[0038] Example 2 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 mode of the ambient temperature sensor lead 14 includes a dual-lead mode. In the dual-lead mode, the time-sharing multiplexing circuit includes a balun, which converts the two leads of the ambient temperature sensor into a differential signal; 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 to convert the antennas into differential leads.

[0039] The RF switch and the analog switch are coupled to the two output ends of the balun respectively; the DC component is isolated by a capacitor and then connected to the two leads of the ambient temperature sensor, one of which is connected to the RC charge and discharge 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.

[0040] In the RF stage: the VCTL_IO port is at a low level, the RF switch is closed, and the analog switch is disconnected. At this time, the RF circuit for wireless transmission is connected to the ambient temperature sensor lead 14. At this time, the RF circuit is connected, and the wireless communication data can be sent through the antenna.

[0041] During the temperature measurement phase: VCTL_IO is high, the RF switch is off, and the analog switch is closed. This disconnects the wireless transmitter's RF circuit from ambient temperature sensor lead 14, disconnecting the RF circuit and connecting the ambient temperature sensor to the temperature measurement circuit. The ambient NTC can now measure temperature. Simultaneously, when the software performs ambient NTC temperature measurement, RC_IO is controlled to output 0, effectively grounding the circuit. This discharges the charge in capacitor C2 in the RF circuit and prevents it from affecting temperature measurement. After discharge, the timing is started, and RC_IO is simultaneously pulled high to charge the ambient temperature sensor and capacitor C1. Because the RF switch is off, capacitor C2 does not form a circuit and therefore does not charge. When the charge in the RC charge / discharge capacitor C1 reaches a certain value, meeting the interrupt voltage at Interupt_IO, an interrupt is generated. The timing is then stopped, and the charging time is calculated as the corresponding temperature. Immediately after the measurement, both RC_IO and Interupt_IO are pulled low to discharge the charge in the RC charge / discharge capacitor C1. After discharge, RC_IO and Interupt_IO are set to open-drain outputs.

[0042] In another embodiment, the present application also discloses a method for manufacturing a high-temperature wireless temperature probe, which specifically includes the following steps: S1: Insert the PCBA board 11 into the metal needle tube 12, position the lead temperature sensor probe end to the tip of the metal needle tube 12, and make the positive spring 111 contact the inner wall of the metal needle tube 12; wrap the PCBA board 11 with the thermal pad.

[0043] In this embodiment, the prefabricated PCBA board 11 is inserted into the metal needle tube 12, ensuring that the probe end of the lead temperature sensor is at the tip of the metal needle tube 12, and the metal springs on both sides of the PCBA board 11 (i.e., the positive springs 111) are in close contact with the inner wall of the metal needle tube 12 to form a charging positive electrode circuit; a high thermal conductivity silicone pad or phase change sheet material is wrapped around the outer periphery of 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 glue.

[0044] S2: The ceramic insulating ring 2 is tightly fitted and pressed with the end of the metal needle tube 12 and the front end of the coaxial coupling connecting shaft 3 in sequence, and solidified to form an insulating sealing structure.

[0045] In this embodiment, high-temperature resistant sealant is evenly 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 fitted and pressed with the end of the metal needle tube 12, and the other end is tightly fitted and pressed with the front end of the coaxial coupling connecting shaft 3. After assembly, the black depth warning identification ring 22 of the ceramic insulating ring 2 is displayed at the joint position. Therefore, when in use, the user can be reminded to submerge the food in the depth warning identification ring 22 for temperature measurement, which has a fool-proof reminder effect.

[0046] Specifically, the ceramic insulating ring 2 forms an insulating isolation layer and an airtight sealing structure after being cured at high temperature, and at the same time realizes radio frequency short circuit protection between the metal needle tube 12 and the coaxial coupling connecting shaft 3.

[0047] 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; and weld and fix the relative positions of the coaxial coupling connecting shaft 3 and the PCBA board 11.

[0048] 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.

[0049] 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; ensure 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 loop; and use a laser spot welding process to fix the relative position of the coaxial coupling connecting shaft 3 and the PCBA board 11.

[0050] S4: Insert the extended section of the ambient temperature sensor lead 14 into the inner cavity of the coaxial coupling connecting shaft 3 and close to the inner wall of the ceramic handle 4, apply glue on the assembly surface of the coaxial coupling connecting shaft 3 and the ceramic handle 4, and solidify to form a multiple sealing structure.

[0051] In this embodiment, the extended section of the ambient temperature sensor lead 14 is used as an antenna radiator.

[0052] Specifically, the lead extension section of the ambient temperature sensor is passed through the inner cavity of the coaxial coupling connecting shaft 3; the end of the lead is close to 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 assembly surface of the ceramic handle 4; after curing, a multiple sealing protection structure is formed at the joint of the coaxial coupling connecting shaft 3 and the ceramic handle 4, and the barb 33 structure of the coaxial coupling connecting shaft 3 prevents glue from penetrating into the coaxial channel.

[0053] It should be understood that the serial numbers of the steps in the above embodiments do not imply the order of execution. The order of execution 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 the present application.

[0054] Those skilled in the art will clearly understand that for the sake of convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by 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.

[0055] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, it should be understood by those skilled in the art that the technical solutions described in the aforementioned embodiments may still be modified, or some of the features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. High-temperature wireless temperature probe based on NTC lead time-sharing multiplexing, characterized by: include: A needle tube assembly (1), a ceramic insulating ring (2), and a coaxial coupling connecting shaft (3) are connected in sequence; the needle tube assembly (1) has a built-in PCBA board (11), and the PCBA board (11) is integrated with: Ambient temperature sensor lead (14), Time-sharing multiplexing circuit, selectively connected to the radio frequency transceiver circuit or the RC charge-discharge temperature measurement circuit; At least two temperature sensors; the ceramic insulating ring (2) is arranged at the junction of the needle tube assembly (1) and the coaxial coupling connecting shaft (3), and the inner cavity forms a closed cavity; The coaxial coupling connecting shaft (3) comprises: The metal outer wall forms a radio frequency signal ground and forms a metal inner conductor of a coaxial transmission structure with the ambient temperature sensor lead (14).

2. The high-temperature wireless temperature probe based on NTC lead time-sharing multiplexing according to claim 1, characterized in that: The time-division multiplexing circuit comprises: a first switch module for controlling the connection and disconnection between the radio frequency matching circuit and the ambient temperature sensor lead (14); a second switch module for controlling the connection and disconnection between the temperature measuring 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 are switched between the radio frequency mode and the temperature measurement mode through the common IO port of the control unit.

3. The high-temperature wireless temperature probe based on time-sharing multiplexing of NTC leads according to claim 2, characterized in that: The multiplexing mode of the ambient temperature sensor lead (14) includes a single lead mode. In the single lead mode, The first switch module includes a radio frequency switch and a capacitor, one end of the radio frequency switch is coupled to a lead of the ambient temperature sensor via the capacitor, and the other end is coupled to the control unit via a radio frequency 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 the RC charge-discharge temperature measurement circuit. When the common IO port is at a first level, the radio frequency switch is closed and the analog switch is opened, and the ambient temperature sensor lead (14) is connected to the radio frequency signal path; When the common IO port is at the second level, the radio frequency switch is disconnected and the analog switch is closed, and the ambient temperature sensor lead (14) is connected to the temperature measurement circuit path.

4. The high-temperature wireless temperature probe based on NTC lead time-sharing multiplexing according to claim 2, characterized in that: The multiplexing mode 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 a differential signal; 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 capacitance and the charge-discharge time constant.

5. The high-temperature wireless temperature probe based on NTC lead time-sharing multiplexing according to claim 1, characterized in that: The needle tube assembly (1) further comprises a metal needle tube (12) and a battery (13) welded to the front end of the PCBA board (11); one of the temperature sensors is provided in the form of a lead, the lead end is welded to the PCBA board (11), and the probe end extends to the tip of the metal needle tube (12); The PCBA board (11) is provided with a metal spring that contacts the inner wall of the metal needle tube (12) as a charging positive electrode; 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), and a negative electrode spring (112) is provided to connect the grounding end of the PCBA board (11) and the inner wall of the thin tube section (31), thereby forming a charging circuit.

6. The high-temperature wireless temperature probe based on time-division multiplexing of NTC leads according to claim 5, characterized in that: The ceramic insulating ring (2) is arranged at the joint between the metal needle tube (12) and the coaxial coupling connecting 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 a glue coating groove (21) to achieve insulation isolation between the metal needle tube (12) and the inner conductor of the coaxial coupling connecting shaft (3).

7. The high-temperature wireless temperature probe based on NTC lead time-sharing multiplexing according to claim 1, characterized in that: The invention also comprises a ceramic handle (4), wherein the inner diameter of the ceramic handle (4) is adapted to the diameter of the ambient temperature sensor probe, and the end of the ambient temperature sensor pin is closely attached to the inner wall of the ceramic handle (4) to sense the temperature; and a positioning groove (41) is set at the bottom of the ceramic handle (4) to form an interference fit with the end of the ambient temperature sensor pin.

8. The high-temperature wireless temperature probe based on time-division multiplexing of NTC leads according to claim 7, characterized in that: The coaxial coupling connecting shaft (3) comprises: The metal outer wall contains the coaxial channel. The annular groove (32) and the barb (33) designed at the inner end cooperate with the glue storage groove on the outer wall of the ceramic handle (4) to form a glue sealing cavity.

9. The high-temperature wireless temperature probe based on time-division multiplexing of NTC leads according to claim 7, characterized in that: The PCBA board (11) has a plurality of equidistantly distributed patch temperature sensors integrated therein and a thermal pad wrapped around the periphery; the outer surface of the ceramic insulating ring (2) is provided with a depth warning marking ring (22); and the extended section of the ambient temperature sensor lead (14) serves as an antenna radiator.

10. A method for manufacturing a high-temperature wireless temperature probe, characterized in that: The following steps are involved: Insert the PCBA board (11) into the metal needle tube (12), position the lead-type temperature sensor probe end at the tip of the metal needle tube (12), and make the positive electrode spring (111) contact the inner wall of the metal needle tube (12); wrap the PCBA board (11) with the thermal pad; The ceramic insulating ring (2) is tightly fitted and pressed with the end of the metal needle tube (12) and the front end of the coaxial coupling connecting shaft (3) in sequence, and solidified to form an insulating sealing structure; 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; and weld and fix the relative positions of the coaxial coupling connecting shaft (3) and the PCBA board (11); The extended section of the ambient temperature sensor lead (14) is inserted into the inner cavity of the coaxial coupling connecting shaft (3) and is closely attached to the inner wall of the ceramic handle (4). Glue is applied to the assembly surface of the coaxial coupling connecting shaft (3) and the ceramic handle (4) and cured to form a multiple sealing structure.

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