High-temperature-resistant low-temperature-drift eddy current sensor

Abstract

The utility model discloses a high temperature resistant low temperature drift type electric eddy current sensor relates to electric eddy current sensor technical field, this high temperature resistant low temperature drift type electric eddy current sensor, including protective cover, metal casing, tail support block, armoring cable and the beryllium oxide ceramic integrated double skeleton assembly in protective cover, double skeleton assembly encloses symmetrical coil groove, built -in measurement and reference double coil, its inside is equipped with through heat glue cavity, through the benzene group organic silicon heat conducting adhesive of glue liquid inlet injection, exhaust hole exhaust, realize coil all -round package, and tail support block is equipped with connecting chamber and protective shell protection cable welding spot, the utility model establishes low resistance heat conduction path through ceramic skeleton, realizes double coil heat synchronization, and cooperates elastic heat conducting adhesive and eliminates thermal stress, and the common mode rejection ratio is greatly promoted, and the whole temperature domain measurement stability is excellent, and the precision measurement of adaptable extreme industrial scene.

Description

Technical Field

[0001] This utility model relates to the field of eddy current sensor technology, and in particular to a high-temperature and low-temperature drift-resistant eddy current sensor. Background Technology

[0002] Eddy current sensors, as non-contact measuring devices, are widely used in precision measurement fields such as mechanical vibration, displacement, and thickness measurement due to their advantages such as high resolution, high frequency response, and immunity to oil, sewage, and dust. Their basic working principle is that a coil inside the sensor probe generates an alternating magnetic field when a high-frequency alternating current is applied. When this magnetic field approaches a metal conductor, eddy currents are generated on the conductor's surface. The counter-magnetic field generated by these eddy currents changes the coil's impedance. By measuring the change in coil impedance, the distance between the coil and the conductor surface, or other physical parameters of the measured object, can be determined. However, an inherent and significant technical challenge of traditional single-coil eddy current sensors is temperature drift. That is, when the probe's own temperature changes, even if the distance to the measured target remains constant, the output signal will change, leading to measurement errors. Temperature drift mainly originates from the following factors.

[0003] The thermal effect of coil resistance: Coils are usually wound with copper wire, whose resistivity has a positive temperature coefficient. As the temperature increases, the ohmic resistance of the coil increases.

[0004] Due to the thermal effect of thermal materials, a magnetic core is often installed inside the probe to enhance the magnetic field. The permeability of the core changes with temperature, which affects the coil inductance.

[0005] The thermal effects of electronic components, such as oscillators and amplifiers, and how their parameters change with temperature.

[0006] To address the temperature drift problem, those skilled in the art have proposed a dual-coil differential compensation structure. This structure typically includes a measuring coil and a reference coil. The measuring coil faces the measured metal conductor, and its impedance is affected by both distance and temperature. The reference coil is physically shielded (e.g., a metal cover) to isolate it from the measured conductor, and its impedance is ideally affected only by temperature. Connecting the two coils to a differential circuit such as a Wheatstone bridge can theoretically cancel out the common-mode interference caused by temperature changes, thereby outputting a stable signal that is only dependent on distance. This method is currently the mainstream technology for reducing temperature drift in high-performance eddy current sensors.

[0007] For relevant prior art, please refer to patent literature, such as CN102721378A, which discloses a differential eddy current sensor that uses two inductor coils connected in reverse series to compensate for the effect of temperature. Utility Model Content

[0008] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a high-temperature and low-temperature drift-resistant eddy current sensor that can solve the above-mentioned technical problems.

[0009] To achieve the above objectives, this utility model provides the following technical solution: a high-temperature and low-temperature drift-resistant eddy current sensor, comprising a protective cover, a metal housing, a tail support block, and an armored cable. The metal housing is fixedly connected to the right end of the protective cover, and the tail support block is fixedly connected to the right end of the metal housing. A connecting chamber is provided at the right end of the tail support block, and the armored cable is installed in the connecting chamber. A protective shell is provided between the left end of the armored cable and the inner wall of the connecting chamber. A dual-frame assembly is fixedly installed inside the protective cover.

[0010] Preferably, the dual-frame assembly includes a main frame, connecting blocks, and secondary frames. The main frame is the body of the dual-frame assembly. There are two connecting blocks, which are fixedly connected to the middle of the left and right ends of the main frame. There is one secondary frame, which is fixedly connected to the opposite ends of the two connecting blocks. The main frame, connecting block, and secondary frame are integrally formed, and the main frame, connecting block, and secondary frame together form a coil groove.

[0011] Preferably, the coil slot is composed of a second coil slot located at the left end of the dual-frame assembly and a first coil slot located at the right end, with the first coil installed in the second coil slot and the second coil installed in the first coil slot.

[0012] Preferably, a set of through-hole hot glue cavities are provided on the main frame and the secondary frame.

[0013] Preferably, the hot glue cavity is filled with thermally conductive adhesive.

[0014] Preferably, the main frame has four glue inlets and vent holes.

[0015] Preferably, the four adhesive inlets are located above the main frame, and the four vent holes are located below the main frame.

[0016] Preferably, both the adhesive inlet and the vent are connected to the hot adhesive chamber.

[0017] Compared with the prior art, the beneficial effects of this utility model are: 1. This high-temperature and low-temperature drift-resistant eddy current sensor uses a symmetrical design with an integrated beryllium oxide ceramic double frame to ensure consistent heat conduction paths for both coils, achieving synchronous thermal response and significantly improving the common-mode rejection ratio. At the same time, the highly adaptable phenyl silicone thermally conductive adhesive can eliminate thermal mismatch stress between the package and the coil, avoiding nonlinear drift of coil parameters. Compared with conventional differential structures, it has a more stable compensation effect in a wide temperature range and under conditions of rapid temperature changes, meeting the stringent requirements of high-precision measurement scenarios.

[0018] 2. This high-temperature and low-temperature drift-resistant eddy current sensor uses beryllium oxide ceramic material for its dual-frame assembly, abandoning the traditional magnetic core structure and reducing the interference of magnetic material thermal effects on inductance parameters. The low thermal expansion coefficient of beryllium oxide ceramic can avoid coil relative position shift caused by frame deformation. The elastic properties of phenyl silicone thermally conductive adhesive can absorb thermal stress and prevent additional fluctuations in coil resistance due to mechanical stress. Combined with the differential compensation structure, it achieves comprehensive suppression of multi-dimensional temperature drift factors such as coil resistance thermal effects and magnetic element thermal effects. The overall measurement error is far lower than that of traditional single-coil sensors.

[0019] 3. This high-temperature and low-temperature drift-resistant eddy current sensor adopts a dual-coil differential compensation structure. Coil 1 is used as the measuring coil, and coil 2 is used as the reference coil and connected to the differential circuit. This can cancel the common-mode interference caused by temperature changes to the dual coils, so that the output signal is only related to physical parameters such as the measured distance. At the same time, it is equipped with a beryllium oxide ceramic dual-frame component and phenyl silicone thermal conductive adhesive to establish a low-resistance heat conduction path and realize the thermal synchronous response of the dual coils. This solves the problem of compensation failure during temperature transients caused by insufficient thermal coupling in conventional differential structures. Compared with traditional single-coil sensors, the drift of the measurement signal is greatly reduced across the entire temperature range, and the measurement accuracy and stability are significantly improved. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the high-temperature and low-temperature drift-type eddy current sensor of this utility model; Figure 2 This is a schematic diagram of the internal assembly structure of the probe in the high-temperature and low-temperature drifting eddy current sensor of this utility model. Figure 3 This is a schematic diagram of the skeleton structure of the high-temperature and low-temperature drifting eddy current sensor of this utility model; Figure 4 This is a schematic diagram of the internal structure of the tail support block in the high-temperature and low-temperature drifting eddy current sensor of this utility model.

[0021] Reference numerals: 1. Protective cover; 2. Metal shell; 3. Tail support block; 4. Armored cable; 5. Main frame; 6. Adhesive inlet; 7. Vent; 8. Cable groove one; 9. Cable groove two; 10. Secondary frame; 11. Connecting block; 12. Coil one; 13. Coil two; 14. Thermally conductive adhesive; 15. Hot glue cavity; 16. Connecting chamber; 17. Protective shell. Detailed Implementation

[0022] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0023] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] In the description of this utility model, terms such as greater than, less than, and exceeding are understood to exclude the stated number, while terms such as above, below, and within are understood to include the stated number. The use of terms like "first" and "second" is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the quantity or sequence of the indicated technical features.

[0025] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0026] Please see Figure 1-4 This utility model provides a technical solution: a high temperature and low temperature drift type eddy current sensor, including a protective cover 1, a metal shell 2 and an armored cable 4. The metal shell 2 is fixedly connected to the right end of the protective cover 1. A tail support block 3 is fixedly connected to the right end of the metal shell 2. A connecting chamber 16 is opened at the right end of the tail support block 3. The armored cable 4 is installed in the connecting chamber 16. A protective shell 17 is provided between the left end of the armored cable 4 and the inner wall of the connecting chamber 16. The protective cover 1 is fixedly installed with a double frame assembly, including a main frame 5, a connecting block 11 and a secondary frame 10. The main frame 5 is the main body of the double frame assembly. There are two connecting blocks 11, and the connecting blocks 11 are fixedly connected to the middle of the left and right ends of the main frame 5. The secondary frames 10 are all fixedly connected to one end of the same connecting block 11. The main frame 5, the connecting block 11 and the secondary frame 10 are integrally formed. A coil groove is formed between the main frame 5, the connecting block 11 and the secondary frame 10. The coil groove is composed of the second wire groove 9 at the left end and the first wire groove 8 at the right end. Coil 12 is installed in the second wire groove 9, and coil 23 is installed in the first wire groove 8. The double frame assembly is a one-piece molded structure. Its low thermal expansion coefficient can prevent the frame and protective cover 1 from deforming due to drastic temperature changes, prevent the relative position of coil 12 and coil 23 from shifting, and reduce parameter drift caused by structural deformation. Both the secondary frame 10 and the main frame 5 have through-hole hot glue cavities 15. The main frame 5 has a set of eight circular array holes in the middle. The four upper holes are glue inlets 6, and the four lower holes are vent holes 7. The glue inlets 6 and the hot glue cavities 15 are connected, and the vent holes 7 are also connected to the hot glue cavities 15. Thermally conductive adhesive 14 is installed in the hot glue cavities 15. A low-resistance heat conduction path is established inside the dual frame assembly, so that the coil 13 in the first slot 8 and the coil 12 in the second slot 9 can achieve thermal synchronization response, which greatly improves the common mode rejection ratio. The circular array layout of multiple inlets and multiple vent holes 7 makes the thermally conductive adhesive 14 more evenly distributed in the hot glue cavities 15, further enhancing the heat conduction consistency of the dual coil area, and can wrap the coil in all directions, improving the sealing and protection capabilities of the overall structure. Both the protective cover 1 and the dual-frame assembly are made of beryllium oxide ceramic. Because beryllium oxide ceramic has a low coefficient of thermal expansion and a high thermal conductivity, it ensures the consistency, high temperature resistance and high thermal conductivity during the assembly of the dual coils. The thermally conductive adhesive 14 is made of phenyl silicone thermally conductive adhesive 14. The phenyl silicone thermally conductive adhesive 14 can fully penetrate between the turns of the dual coil, eliminate all air, and reduce the internal stress generated on the coil during the curing process. After curing, the adhesive should have a certain elasticity to absorb thermal stress and prevent the hard and brittle epoxy resin from cracking under thermal shock.

[0027] Working principle: First, both the protective cover 1 and the dual-frame assembly are made of beryllium oxide ceramic, and the dual-frame assembly is a one-piece molded structure. Its low coefficient of thermal expansion can prevent the frame and protective cover 1 from deforming due to drastic temperature changes, ensuring that the relative positions of coil 13 in wire slot 8 and coil 12 in wire slot 9 are fixed. At the same time, phenyl silicone thermally conductive adhesive 14 is injected into the hot glue cavity 15 through the adhesive inlet 6. Air is discharged through the exhaust hole 7. The thermally conductive adhesive 14 is evenly filled and fully wraps the dual coils. Its elastic properties can absorb thermal stress and prevent the coils from drifting due to stress, thus laying a solid structural and thermal protection foundation for the stable operation of the sensor. Next, high-frequency alternating current is applied to coil 12 and coil 23. When coil 12 is brought close to the metal conductor being tested, the alternating magnetic field it generates will induce eddy currents on the surface of the conductor. The reverse magnetic field formed by these eddy currents will change the impedance of coil 12. The amount of impedance change is related to physical parameters such as the distance between coil 12 and the conductor being tested. However, due to the shielding and structural design of the dual-frame assembly, coil 23 does not induce eddy currents with the conductor being tested and is only affected by the ambient temperature. Then, the beryllium oxide ceramic material of the dual-framework assembly has a high thermal conductivity, and a low-resistance heat conduction path is established inside it, which allows coil 12 and coil 23 to achieve thermal synchronous response. The impedance of the two will generate consistent common-mode interference due to temperature changes. At the same time, the uniformly distributed thermally conductive adhesive 14 further enhances the consistency of heat conduction in the dual-coil area, ensuring that the temperature affects the dual coils synchronously and equally. Then, by connecting the two coils to the differential circuit, the common-mode interference caused by temperature can be canceled out, and only the impedance change signal related to the measured physical parameter is retained, which greatly improves the measurement accuracy. Finally, the effective electrical signal after differential compensation is transmitted through the armored cable 4 connected to the dual coil. The connecting chamber 16 in the tail support block 3 provides a stable installation space for the armored cable 4. The protective shell 17 between the cable and the inner wall of the chamber can protect the welded joint between the cable and the coil, avoiding external environmental corrosion and external force pulling that may affect signal transmission. Finally, the accurate measured physical parameter signal is stably output to the external receiving device, completing the entire measurement process.

[0028] Structural Description: Protective Cover 1: Protective Cover 1 is made of beryllium oxide ceramic material, which houses and fixes the dual-frame assembly, providing external protection for core components such as internal coils. This material has a low coefficient of thermal expansion and a high thermal conductivity. On the one hand, it can prevent deformation caused by drastic temperature changes, prevent the installation position of the internal dual-frame assembly and coils from shifting, and reduce parameter drift caused by structural deformation. On the other hand, it can help the dual-frame assembly establish an overall low-resistance thermal conduction environment, improve the thermal response consistency of the dual coils, and also isolate external dust, moisture and other corrosion, enhancing the environmental adaptability of the sensor. Metal housing 2: Metal housing 2 is fixedly connected to the right end of protective cover 1, connecting protective cover 1 and tail support block 3 to form the middle section protection structure of the sensor, enhancing the overall mechanical rigidity and impact resistance of the sensor. At the same time, with the protective properties of metal material, it further protects the internal components from external force collision damage, ensures the stability of the overall sensor structure, and provides a solid transition support for the connection of core components and tail cable. Tail support block 3: Tail support block 3 is fixedly connected to the right end of metal shell 2. A connection chamber 16 is opened to install armored cable 4, providing a fixed space for the connection between the cable and the internal coil, limiting the connection end of armored cable 4, preventing the cable from loosening due to external force, ensuring the stability of signal transmission, and providing an installation base for protective shell 17 to enhance the protection effect at the cable connection point. Armored cable 4: The armored cable 4 is installed in the connection chamber 16 and transmits the effective electrical signal after differential compensation. It stably transmits the measurement signal inside the sensor to the external receiving device. The armored characteristics make it resistant to bending and interference. With the protection of the protective shell 17, it can avoid interference from the external environment to the signal transmission and ensure accurate and stable output of measurement data. Main frame 5: The main frame 5 is the main body of the dual frame assembly. Together with the connecting block 11 and the secondary frame 10, it is an integrally formed beryllium oxide ceramic structure, which forms the mounting foundation for the dual coils. At the same time, it has a hot glue cavity 15 and a circumferential array of holes. The integrally formed beryllium oxide ceramic has a low coefficient of thermal expansion, which can prevent the coils from shifting due to its own deformation. The high thermal conductivity can establish a low-resistance heat conduction path and realize the thermal synchronous response of the dual coils. The hot glue cavity 15 and the hole array provide channels for the filling and venting of the thermally conductive adhesive 14, ensuring uniform distribution of the adhesive. Adhesive Inlet 6: Adhesive inlet 6 consists of four through holes located above the middle of the main frame 5 and connected to the hot glue cavity 15. It provides an injection channel for the phenyl silicone thermal conductive adhesive 14. This multi-inlet circumferential array layout allows the thermal conductive adhesive 14 to enter the hot glue cavity 15 simultaneously from multiple directions, ensuring that the adhesive can penetrate evenly between the turns of the dual coils and the gaps in the frame, avoiding local adhesive accumulation or insufficient filling, and providing all-round wrapping and protection for the coil. Vent 7: Vent 7 consists of four through holes located in the lower middle part of the main frame 5 and connected to the hot glue cavity 15 to expel air from the hot glue cavity 15. The circumferential array layout of the multiple vent holes 7 can completely expel residual air from the cavity when the thermally conductive adhesive 14 is injected, avoid the generation of air bubbles in the adhesive, ensure the density of the thermally conductive adhesive 14 filling, and at the same time enhance the heat conduction consistency of the dual coil area and improve the temperature compensation effect. Wire slot 1 8: Wire slot 1 8 is the right-side coil slot formed by the main frame 5, connecting block 11 and secondary frame 10, which fixes and installs coil 2 13. This symmetrical wire slot structure can ensure that the installation position of coil 2 13 is accurate and stable, avoid the displacement of the coil during use, and ensure the stability of parameters such as inductance and resistance of coil 2 13. At the same time, the symmetrical layout can make the heat conduction path of coil 2 13 and coil 1 12 consistent, realize thermal synchronous response, and improve common mode rejection ratio. Wire slot 2 9: Wire slot 2 9 is the left coil slot formed by the main frame 5, connecting block 11 and secondary frame 10. Coil 1 12 is fixedly installed there. This structure is symmetrically designed with wire slot 1 8, which can ensure that the installation environment of coil 1 12 and coil 2 13 is consistent, providing a physical basis for the matching of dual coil parameters. Precise positioning can prevent coil 1 12 from shifting due to external force or temperature deformation, reducing parameter drift, while ensuring the stability of its relative position with the conductor being measured, thus improving measurement accuracy. Secondary frame 10: The secondary frame 10, the main frame 5, and the connecting block 11 are beryllium oxide ceramic integral molding structures. They are fixed at opposite ends of the two connecting blocks 11 respectively. Together with the main frame 5 and the connecting block 11, they form a coil groove and open a through hot glue cavity 15. This integral molding structure has a low coefficient of thermal expansion and a high thermal conductivity, which can prevent its own deformation from affecting the coil position. At the same time, it can help the main frame 5 establish a complete low-resistance heat conduction path to achieve thermal synchronization of the two coils. The hot glue cavity 15 can ensure that the thermally conductive adhesive 14 evenly covers the coil and absorbs thermal stress. Connecting Block 11: There are two connecting blocks 11, which are fixed in the middle of the left and right ends of the main frame 5 respectively. They are integrally formed with the main frame 5 and the secondary frame 10, and are made of beryllium oxide ceramic. They connect the main frame 5 and the secondary frame 10, and together they enclose the coil groove to ensure the symmetry of the double coil groove and provide consistent installation space for the double coil. The integrally formed ceramic material can ensure the continuity of the heat conduction path, help the double coil to achieve thermal synchronous response, and at the same time enhance the overall mechanical rigidity of the double frame assembly to avoid loosening of the assembly. Coil 12: Coil 12 is installed in slot 29 and serves as a measuring coil. When high-frequency alternating current is applied, an alternating magnetic field is generated, which induces eddy currents in the metal conductor being measured. The measured physical parameters are then fed back through impedance changes. This coil and coil 213 are wound with the same batch of wire, resulting in low parameter deviation. Combined with the thermal synchronization design of the dual-frame assembly, it can form common-mode interference with the reference coil while being affected by temperature. After being connected to the differential circuit, the temperature drift effect can be canceled, retaining only the effective measurement signal and improving measurement accuracy. Coil 2 13: Coil 2 13 is installed in slot 1 8 as a reference coil. After being energized with high-frequency AC, it is only affected by the ambient temperature and does not generate eddy current induction with the conductor being measured. This coil is symmetrical in structure and matched with the parameters of coil 1 12. With the thermal synchronization design of the beryllium oxide ceramic skeleton, it can generate the same temperature-type impedance change as the measuring coil. After being connected to the differential circuit, it can completely cancel the common-mode interference caused by temperature, ensuring that the output signal is only related to the measured physical parameters and greatly reducing temperature drift error. Thermally conductive adhesive 14: Thermally conductive adhesive 14 is made of phenyl silicone and is filled in the hot adhesive cavity 15. It completely wraps the dual coils and fills the gap between the skeleton and the coils. This adhesive has a high thermal conductivity, which can enhance the heat conduction consistency of the dual coil area and help the thermal synchronous response. The low curing shrinkage rate can reduce the internal stress on the coils during the curing process. The elastic properties can absorb thermal stress and avoid the problem of cracking of hard and brittle epoxy resin. At the same time, it can isolate external moisture and dust, improve the protection capability and service life of the sensor. Hot glue cavity 15: Hot glue cavity 15 is a cavity that runs through the secondary frame 10 and the main frame 5, providing a space for thermally conductive adhesive 14. It also connects the adhesive inlet 6 and the vent 7. This through-type cavity allows the thermally conductive adhesive 14 to fully penetrate between the turns of the dual coils and the gaps in the frame, ensuring uniform distribution of the adhesive. At the same time, the high thermal conductivity of the adhesive can enhance the heat conduction path of the dual frame assembly, achieving thermal synchronization of the dual coils. It can also provide mechanical protection for the coils by wrapping them with the adhesive, reducing stress damage. Connection chamber 16: The connection chamber 16 is located at the right end of the tail support block 3, providing installation space for the armored cable 4 and a placement position for the protective shell 17. It precisely limits the connection end of the armored cable 4 to prevent the cable from loosening due to external force pulling, ensuring the stability of signal transmission. At the same time, it creates an independent protective space for the connection between the cable and the internal coil to reduce the risk of external environmental corrosion. Protective housing 17: The protective housing 17 is located between the left end of the armored cable 4 and the inner wall of the connecting chamber 16. It protects the welded joint between the armored cable 4 and the internal coil, achieving insulation protection, avoiding short circuits at the solder joints, and buffering the stress on the internal coil pins caused by cable pulling, preventing pin breakage or loosening, ensuring the continuity and stability of signal transmission, and extending the service life of the sensor.

[0029] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A high-temperature and low-temperature drift-resistant eddy current sensor, comprising a protective cover (1), a metal housing (2), a tail support block (3), and an armored cable (4), characterized in that: The metal shell (2) is fixedly connected to the right end of the protective cover (1), the tail support block (3) is fixedly connected to the right end of the metal shell (2), the right end of the tail support block (3) is provided with a connecting chamber (16), the armored cable (4) is installed in the connecting chamber (16), and a protective shell (17) is provided between the left end of the armored cable (4) and the inner wall of the connecting chamber (16). A double-frame assembly is fixedly installed inside the protective cover (1).

2. The high-temperature and low-temperature drift-resistant eddy current sensor according to claim 1, characterized in that: The dual-frame assembly includes a main frame (5), connecting blocks (11) and a secondary frame (10). The main frame (5) is the main body of the dual-frame assembly. There are two connecting blocks (11) and they are fixedly connected to the middle of the left and right ends of the main frame (5). There is one secondary frame (10) and it is fixedly connected to the opposite ends of the two connecting blocks (11). The main frame (5), connecting block (11) and secondary frame (10) are integrally formed structures, and the main frame (5), connecting block (11) and secondary frame (10) enclose a coil groove.

3. The high-temperature and low-temperature drift-resistant eddy current sensor according to claim 2, characterized in that: The coil slot is composed of a second (9) slot located at the left end of the double-frame assembly and a first (8) slot located at the right end. The first (12) coil is installed in the second (9) slot and the second (13) coil is installed in the first (8) slot.

4. The high-temperature and low-temperature drift-resistant eddy current sensor according to claim 3, characterized in that: The main frame (5) and the secondary frame (10) are provided with through-hole hot glue cavities (15).

5. The high-temperature and low-temperature drift-resistant eddy current sensor according to claim 4, characterized in that: Each of the hot glue cavities (15) is filled with thermally conductive adhesive (14).

6. The high-temperature and low-temperature drift-resistant eddy current sensor according to claim 5, characterized in that: The main frame (5) has four glue inlets (6) and vent holes (7).

7. The high-temperature and low-temperature drift-resistant eddy current sensor according to claim 6, characterized in that: The four adhesive inlets (6) are located above the main frame (5), and the four vent holes (7) are located below the main frame (5).

8. The high-temperature and low-temperature drift-resistant eddy current sensor according to claim 7, characterized in that: The adhesive inlet (6) and the vent (7) are both connected to the hot adhesive chamber (15).

Images