Eddy current sensor

Abstract

The utility model relates to an eddy current sensor, which comprises a shell, an eddy current assembly and a positioning assembly, wherein the eddy current assembly and the positioning assembly are arranged in the shell; one end of the shell is closed to form an induction surface; the eddy current assembly at least comprises a tank-type magnetic core with an opening facing the induction face and a coil installed in the tank-type magnetic core. The positioning assembly at least comprises a positioning column with one end abutting against the tank-type magnetic core and a positioning plate fixedly connected with the shell, the positioning plate is provided with at least one threaded hole and pre-tightening screws in one-to-one correspondence with the threaded holes, and one end of each pre-tightening screw extends out of the corresponding threaded hole to abut against the positioning column. The utility model has the advantages that the pre-tightening force between the shell and the magnetic core can be flexibly adjusted, the problem that the traditional structural design is easily interfered by environmental temperature fluctuation and the natural aging process of encapsulating materials is effectively solved, the assembly precision is high, the long-term use performance is stable, and the environmental adaptability is strong.

Description

Technical Field

[0001] The utility model relates to the technical field of sensors, in particular to an eddy current sensor. Background Art

[0002] Eddy-current sensors, high-precision measuring devices based on the principle of electromagnetic induction, have been widely used and promoted in fields such as industrial automation, vibration monitoring of rotating machinery, and precision measurement. Their unique operating principle enables efficient and accurate non-contact detection of the distance, displacement, and position of metal objects. In Applied Materials' semiconductor RTP (rapid thermal processing) equipment, eddy-current sensors (P / N: 0190-14176) are used for non-contact, precise detection of the spatial posture of magnetically suspended rotors. These eddy-current sensors consist of at least a metal housing, an eddy-current coil, a pot-shaped magnetic core, a positioning post, and a potting compound for securing them.

[0003] Specifically, when a metal object approaches or moves away from the sensor's eddy current coil, electromagnetic induction generates eddy currents within the metal object. These eddy currents in turn affect the inductance of the sensor's eddy current coil, enabling precise measurement of the distance or displacement between the metal object and the sensor. This measurement method not only offers the advantage of non-contact, avoiding the wear and interference associated with direct contact, but also maintains stable performance in harsh environments such as high temperatures and high pressures.

[0004] Existing eddy-current sensors face the dual challenges of poor long-term stability and inconsistent assembly precision. In particular, when potting adhesive is used to secure the eddy-current coil and pot-shaped magnetic core, sensor performance is susceptible to fluctuations in ambient temperature and the natural aging of the potting material. Over time, the potting material can age, crack, and degrade, especially in environments subject to drastic temperature and humidity fluctuations. This aging can exacerbate the loosening of internal components, directly impairing the sensor's long-term stable operation.

[0005] Furthermore, the uneven distribution of the potting compound during the curing phase, combined with wide tolerances in the manufacturing process, often results in inconsistent distances between the pot core and the housing. This factor becomes a key obstacle to sensor detection accuracy and overall product consistency. Further complicating matters, the significant difference in thermal expansion coefficients between the potting material and metal components (such as the housing and core) triggers significant thermal expansion and contraction effects when exposed to high or low temperatures, subjecting internal components to uneven mechanical stresses that compromise structural stability and measurement accuracy. Under extreme environmental conditions, the sensor may even shift, deform, or even become damaged, severely hindering its proper function. Summary of the Invention

[0006] The technical problem to be solved by the utility model is to provide an eddy current sensor that can flexibly adjust the preload force between the shell and the magnetic core, effectively overcoming the problem that the traditional structural design is easily affected by ambient temperature fluctuations and the natural aging process of the potting material, and has high assembly precision, stable long-term performance and strong environmental adaptability.

[0007] In order to solve the above technical problems, the utility model provides a technical solution, an eddy current sensor, comprising at least a shell, an eddy current component installed in the shell, and a positioning component; one end of the shell is closed to form a sensing surface for detection; the eddy current component comprises at least a pot-shaped magnetic core with an opening facing the sensing surface and a coil installed in the pot-shaped magnetic core; the positioning component comprises at least a positioning column with one end abutting the pot-shaped magnetic core and a positioning plate fixedly connected to the shell, the positioning plate being provided with at least one threaded hole and a pre-tightening screw corresponding one-to-one to the threaded hole, one end of the pre-tightening screw extending out of the threaded hole and abutting against the positioning column.

[0008] In a preferred embodiment, the inner cavity of the shell includes a first mounting cavity and a second mounting cavity, a first step portion is provided at the connection position between the first mounting cavity and the second mounting cavity, the sensing surface is located on the top wall of the first mounting cavity, the pot-shaped magnetic core and the positioning column are installed in the first mounting cavity in sequence, and the positioning plate is adapted to the second mounting cavity and fixedly connected to the first step portion.

[0009] In a preferred embodiment, the side wall of the first installation cavity protrudes outward to form a second step portion, the first step portion is provided with a sealing surface arranged parallel to the sensing surface, and the sealing surface is provided with an annular groove;

[0010] The outer surface of the second step portion protrudes outward to form a third step portion. The top wall of the third step portion is provided with a mounting surface parallel to the sealing surface. The mounting surface is provided with a plurality of mounting holes spaced apart along the circumference.

[0011] In a preferred embodiment, a glue groove communicating with the second installation cavity and a clearance groove arranged in a one-to-one correspondence with the installation holes are provided on a side of the shell away from the first installation cavity.

[0012] In a preferred embodiment, the pot-type magnetic core includes a base adapted to the inner wall surface of the shell, and an annular side wall and the opening formed by extending outward from the edge of the base, the base protrudes along the extension direction of the annular side wall to form a magnetic core portion, and the coil is wound on the outer surface of the magnetic core column and is coaxially arranged with the annular side wall.

[0013] In a preferred embodiment, a through hole is provided at the center of an end face of one side of the base away from the opening; the positioning column is provided with a positioning portion adapted to the through hole, and the positioning portion of the positioning column is embedded in the through hole and abuts against an end face of the side of the base away from the opening, thereby pressing one end of the opening of the pot-shaped magnetic core against the inner wall of the shell.

[0014] In a preferred embodiment, the positioning column includes a first abutting portion for abutting against the base, a second abutting portion for abutting against the pre-tightening screw and arranged parallel to the first abutting portion, and a connecting portion located between the first abutting portion and the second abutting portion, and the positioning portion is located on the first abutting portion.

[0015] In a preferred embodiment, the annular side wall of the pot-shaped magnetic core is provided with at least one wire groove matching the coil lead;

[0016] And / or the base of the pot-type magnetic core is provided with at least one first wire hole matching the coil lead.

[0017] In a preferred embodiment, the gaps between the positioning plate, the positioning posts, the pot-shaped magnetic core and the inner wall of the housing are filled with potting glue.

[0018] Compared with the prior art, the eddy current sensor of the present invention has the following beneficial effects:

[0019] (1) The eddy current sensor of the present invention comprises at least a shell, an eddy current assembly installed in the shell, and a positioning assembly; one end of the shell is closed to form a sensing surface for detection; the eddy current assembly comprises at least a pot-shaped magnetic core with an opening facing the sensing surface and a coil installed in the pot-shaped magnetic core to ensure the accuracy of detection; the positioning assembly comprises at least a positioning post with one end abutting against the pot-shaped magnetic core and a positioning plate fixedly connected to the shell, the positioning plate being provided with at least one threaded hole and a pre-tightening screw corresponding to the threaded hole, one end of the pre-tightening screw extending out of the threaded hole abutting against the positioning post. The pre-tightening screw squeezes the other end of the positioning post, thereby achieving fine adjustment of the position of the pot-shaped magnetic core. With such a structural design, on the one hand, by simply turning the pre-tightening screw, the positioning post can be easily squeezed, and then, through the transmission action of the positioning post, the pot-shaped magnetic core can be fine-tuned relative to the positioning plate until it fits tightly against the inner wall of the shell. This operation process is simple and quick, which greatly improves the assembly efficiency; on the other hand, by accurately adjusting the tightness of the pre-tightening screw, the pre-tightening force between the pot-shaped magnetic core and the shell can be finely controlled. This adjustment mechanism not only ensures high-precision component assembly, but also effectively improves the consistency of product performance, providing strong guarantees for the long-term stable operation of the sensor.

[0020] (2) In the eddy current sensor of the present invention, the threaded hole of the positioning plate is adapted to the pre-tightening screw, and one end of the pre-tightening screw extends out of the threaded hole and abuts against the end face of the positioning column. Through the relative rotational movement between the pre-tightening screw and the thread, the positioning column can be accurately driven to move slightly relative to the positioning plate. This movement process then drives the position adjustment of the pot-shaped magnetic core, thereby achieving precise adjustment of the pre-tightening force between the pot-shaped magnetic core and the inner wall of the shell. The tiny gaps between the positioning plate, the positioning column, the pot-shaped magnetic core and the inner wall of the shell are filled with potting glue, which further enhances the structural stability and environmental adaptability of the sensor. It not only effectively seals the interior of the sensor to prevent the intrusion of the external harsh environment, but also provides additional mechanical support for the sensor through its tough properties after curing. By combining the adjustment of the mechanical structure pre-tightening screw with the filling of potting glue, a dual protection mechanism of the eddy current sensor is formed. The adjustment of the mechanical structure pre-tightening screw ensures the precise control of the pre-tightening force between the pot-shaped magnetic core and the inner wall of the shell, while the potting glue further enhances the overall rigidity and seismic resistance of the sensor. Therefore, even in high temperature, low temperature or severe vibration environments, the eddy current sensor of the present invention can maintain excellent stability and reliability, providing solid technical support for various precision measurement tasks.

[0021] (3) The eddy current sensor of the present invention has a pot-shaped magnetic core including a base adapted to the inner wall surface of the shell and an annular side wall and an opening formed by extending outward from the edge of the base. The base protrudes along the extension direction of the annular side wall to form a magnetic core portion. The coil is wound on the outer surface of the magnetic core column and is coaxial with the annular side wall. The coil is wound on the outer surface of the magnetic core portion and maintains a coaxial relationship with the annular side wall. This coaxial setting not only optimizes the distribution of the electromagnetic field, but also greatly improves the sensing accuracy of the eddy current sensing component during operation, ensuring the high stability of the signal output. Through this series of ingenious designs, the eddy current sensor of the present invention has achieved a significant improvement in performance, providing a more reliable technical guarantee for various precision measurement scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A three-dimensional partial cross-sectional view of the overall structure of an eddy current sensor embodiment of the present utility model;

[0023] Figure 2 This is a cross-sectional view of the overall structure of an eddy current sensor embodiment of the present utility model;

[0024] Figure 3 This is a schematic structural diagram of an eddy current component of an eddy current sensor embodiment of the present utility model.

[0025] Description of reference numerals:

[0026] 1 - housing; 11 - sensing surface; 12 - first mounting cavity; 13 - second mounting cavity; 14 - first step; 15 - second step; 151 - sealing surface; 152 - annular groove; 16 - third step; 161 - mounting surface; 162 - mounting hole; 17 - adhesive groove; 18 - clearance groove;

[0027] 2- eddy current component; 21- pot-shaped magnetic core; 211- opening; 212- base; 2121- through hole; 2122- first wire hole; 213- annular side wall; 2131- wire groove; 214- magnetic core; 22- coil;

[0028] 3-positioning assembly; 31-positioning column; 311-positioning portion; 312-first abutting portion; 313-second abutting portion; 314-connecting portion; 32-positioning plate; 321-threaded hole; 322-pre-tightening screw;

[0029] 4-Potting glue. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, an integral connection, or a detachable connection; it can be the internal communication of two components; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] An eddy current sensor of this embodiment, such as Figure 1 and Figure 2 As shown, the housing 1 and the eddy current component 2 and the positioning component 3 are installed in the housing. One end of the housing is closed to form a sensing surface 11 for detection. Figure 2As shown, the eddy current assembly comprises at least a pot-shaped magnetic core 21 with an opening 211 facing the inductive surface and a coil 22 mounted within the pot-shaped magnetic core 21. The positioning assembly 3 comprises at least a positioning post 31, one end of which abuts the pot-shaped magnetic core 21, and a positioning plate 32 fixedly connected to the housing. The positioning plate is provided with at least one threaded hole 321 and a pre-tightening screw 322 corresponding to each threaded hole. One end of the pre-tightening screw extends through the threaded hole to squeeze the other end of the positioning post, driving the pot-shaped magnetic core relative to the positioning plate through the positioning post, thereby pressing the pot-shaped magnetic core against the inner wall of the housing. With this structural design, the positioning post can be easily squeezed by simply turning the pre-tightening screw. The transmission action of the positioning post allows the pot-shaped magnetic core to be fine-tuned relative to the positioning plate until it fits tightly against the inner wall of the housing. This simple and quick operation greatly improves assembly efficiency. Furthermore, by precisely adjusting the tightness of the pre-tightening screw, the pre-tightening force between the pot-shaped magnetic core and the housing can be precisely controlled. This adjustment mechanism not only ensures high-precision component assembly, but also effectively improves the consistency of product performance, providing strong guarantees for the long-term stable operation of the sensor.

[0034] In this embodiment, the positioning plate 32 is provided with two threaded holes 321. One end of a preload screw extends through the threaded hole and abuts against the end face of the positioning post. The relative rotation between the preload screw and the thread precisely drives the positioning post to move slightly relative to the positioning plate. This movement, in turn, drives the position of the pot core, thereby achieving precise adjustment of the preload force between the pot core and the inner wall of the housing.

[0035] It should be noted that the positioning plate 32 can be fixedly connected to the housing 1 by screw connection or welding. In this embodiment, the inner cavity of the housing 1 includes a first mounting cavity 12 and a second mounting cavity 13. A first step portion 14 is provided at the connection position between the first mounting cavity and the second mounting cavity. The sensing surface is located on the top wall of the first mounting cavity. The pot-shaped magnetic core 21 and the positioning post 31 are sequentially installed in the first mounting cavity. The positioning plate is adapted to the second mounting cavity and is fixedly connected to the first step portion 14.

[0036] The side wall of the first mounting cavity 12 protrudes outward to form a second step portion 15. The first step portion is provided with a sealing surface 151 arranged parallel to the sensing surface. The sealing surface is provided with an annular groove 152. The annular groove is used to install a sealing ring. The sealing ring can elastically deform in time according to the fitting error during installation to compensate for the fitting error between the two. This design avoids the phenomenon of being too loose or too tight and ensures the reliability of the seal. The outer surface of the second step portion protrudes outward to form a third step portion 16. The top wall of the third step portion is provided with a mounting surface 161 arranged parallel to the sealing surface. The mounting surface is provided with a plurality of mounting holes 162 spaced along the circumference. The design of multiple steps can increase the strength and stability of the overall structure. This design helps to disperse stress and prevent structural damage due to overload of a single part.

[0037] Preferably, a glue groove 17 communicating with the second installation cavity 13 and a clearance groove 18 corresponding to the installation hole 162 are provided on a side of the housing 1 away from the first installation cavity 12 .

[0038] like Figure 3 As shown, the pot-shaped magnetic core 21 includes a base 212 adapted to the inner wall of the shell, and an annular side wall 213 and an opening 211 formed by extending outward from the edge of the base. The base protrudes along the extension direction of the annular side wall to form a magnetic core portion 214. The coil 22 is wound on the outer surface of the magnetic core column and is coaxial with the annular side wall. This coaxial setting not only optimizes the distribution of the electromagnetic field, but also greatly improves the induction accuracy of the eddy current sensing component during operation, ensuring the high stability of the signal output. Through this series of ingenious designs, the eddy current sensor of the utility model has achieved a significant improvement in performance, providing a more reliable technical guarantee for various precision measurement scenarios.

[0039] like Figure 2 As shown, a through-hole 2121 is provided at the center of the end face of the base 212, facing away from the opening 211. The positioning post 31 is provided with a positioning portion 311 that matches the through-hole. The positioning portion of the positioning post is embedded in the through-hole and abuts against the end face of the base facing away from the opening, thereby firmly abutting one end of the pot-shaped magnetic core's opening 211 against the inner wall of the housing. The through-hole structure design not only provides space for the positioning portion 311 of the positioning post 31 to be embedded, but also meets the wiring requirements of the coil leads, achieving dual functional integration.

[0040] Preferably, the positioning column 31 includes a first abutting portion 312 for abutting against the base, a second abutting portion 313 for abutting against the pre-tightening screw and arranged parallel to the first abutting portion, and a connecting portion 314 located between the first abutting portion and the second abutting portion. The positioning portion 311 is located on the first abutting portion. This parallel design not only enables the pre-tightening screw to be evenly stressed when adjusting the pre-tightening force between the pot-shaped magnetic core and the inner wall of the shell, avoiding the jamming phenomenon caused by uneven force, but also further improves the stability and reliability of the entire structure.

[0041] Preferably, the annular side wall 213 of the pot-shaped magnetic core is provided with at least one wire groove 2131 matching the lead wire of the coil 22 ; and / or the base 212 of the pot-shaped magnetic core is provided with at least one first wire hole 2122 matching the lead wire of the coil 22 .

[0042] In this embodiment, the leads of the coil 22 are routed through the wire groove 2131 and the first wire hole 2122 .

[0043] In this embodiment, the gaps and glue grooves 17 between the positioning plate, the positioning column, the pot-shaped magnetic core, and the inner wall of the shell are filled with potting glue 4. This further enhances the structural stability and environmental adaptability of the sensor, effectively sealing the interior of the sensor to prevent the intrusion of harsh external environments, and providing additional mechanical support for the sensor through its tough properties after curing. By combining the adjustment of the mechanical structure pre-tightening screws with the potting glue filling, a dual protection mechanism for the eddy current sensor is formed. The adjustment of the mechanical structure pre-tightening screws ensures the precise controllability of the pre-tightening force between the pot-shaped magnetic core and the inner wall of the shell, while the potting glue further enhances the overall rigidity and shock resistance of the sensor. Therefore, even in high temperature, low temperature or severe vibration environments, the eddy current sensor of the present invention can maintain excellent stability and reliability, providing solid technical support for various precision measurement tasks.

[0044] In short, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An eddy current sensor, characterized in that: The invention comprises at least a shell (1), an eddy current component (2) installed in the shell, and a positioning component (3); one end of the shell is sealed to form an induction surface (11) for detection; the eddy current component comprises at least a pot-shaped magnetic core (21) with an opening (211) facing the induction surface and a coil (22) installed in the pot-shaped magnetic core; the positioning component comprises at least a positioning column (31) with one end abutting against the pot-shaped magnetic core and a positioning plate (32) fixedly connected to the shell, the positioning plate being provided with at least one threaded hole (321) and a pre-tightening screw (322) corresponding to the threaded hole, one end of the pre-tightening screw extending out of the threaded hole and abutting against the positioning column.

2. An eddy current sensor according to claim 1, characterized in that: The inner cavity of the shell (1) includes a first mounting cavity (12) and a second mounting cavity (13); a first step portion (14) is provided at the connection position between the first mounting cavity and the second mounting cavity; the sensing surface is located on the top wall of the first mounting cavity; the pot-shaped magnetic core (21) and the positioning column (31) are sequentially installed in the first mounting cavity; the positioning plate is adapted to the second mounting cavity and is fixedly connected to the first step portion (14).

3. An eddy current sensor according to claim 2, characterized in that: The side wall of the first installation cavity (12) protrudes outward to form a second step portion (15), the first step portion is provided with a sealing surface (151) arranged parallel to the sensing surface, and the sealing surface is provided with an annular groove (152); The outer surface of the second step portion protrudes outward to form a third step portion (16), and the top wall of the third step portion is provided with a mounting surface (161) arranged parallel to the sealing surface, and the mounting surface is provided with a plurality of mounting holes (162) spaced along the circumference.

4. An eddy current sensor according to claim 3, characterized in that: A glue groove (17) communicating with the second installation cavity and a clearance groove (18) arranged in one-to-one correspondence with the installation hole (162) are provided on a side of the housing (1) away from the first installation cavity (12).

5. An eddy current sensor according to any one of claims 1 to 4, characterized in that: The pot-shaped magnetic core (21) comprises a base (212) adapted to the inner wall surface of the shell, an annular side wall (213) formed by extending outward from the edge of the base, and the opening (211); the base protrudes along the extension direction of the annular side wall to form a magnetic core portion (214); the coil (22) is wound on the outer surface of the magnetic core portion and is coaxially arranged with the annular side wall.

6. An eddy current sensor according to claim 5, characterized in that: A through hole (2121) is provided at the center of an end face of one side of the base (212) away from the opening (211); the positioning column (31) is provided with a positioning portion (311) adapted to the through hole, the positioning portion of the positioning column is embedded in the through hole, and abuts against an end face of the side of the base away from the opening, thereby pressing one end of the opening (211) of the pot-shaped magnetic core against the inner wall of the shell.

7. An eddy current sensor according to claim 6, characterized in that: The positioning column (31) comprises a first abutting portion (312) for abutting against the base, a second abutting portion (313) for abutting against the pre-tightening screw and arranged parallel to the first abutting portion, and a connecting portion (314) located between the first abutting portion and the second abutting portion, and the positioning portion (311) is located on the first abutting portion.

8. An eddy current sensor according to claim 7, characterized in that: The annular side wall (213) of the pot-shaped magnetic core is provided with at least one wire slot (2131) matching the lead wire of the coil (22); And / or the base (212) of the pot-shaped magnetic core is provided with at least one first wire hole (2122) matching the lead wire of the coil (22).

9. An eddy current sensor according to any one of claims 1 to 4 or 6 to 8, characterized in that: The gaps between the positioning plate (32), the positioning column (31), the pot-shaped magnetic core (21) and the inner wall of the housing (1) are filled with potting glue (4).

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