阅读说明：本技术 一种电涡流探头及其制造方法 (Electric eddy current probe and manufacturing method thereof ) 是由 徐健 于 2021-08-20 设计创作，主要内容包括：一种电涡流探头及其制造方法,包括电缆和外套件,电缆的端部分别设置有第一铜环、第二铜环和第三铜环；铜环外表面包覆有封装壳体,封装壳体表面分别开设有第一过线槽和第二过线槽,封装壳体端部设置有线圈安装座,线圈安装座外表面固定绕接有线圈,封装壳体外表面设置有限位凸起,限位凸起与线圈安装座之间套接有螺纹套,螺纹套外表面通过螺纹连接有不锈钢壳体,不锈钢壳体外表面与外壳体的内腔相连接。本发明克服了现有技术的不足,以第一铜环和第二铜环为媒介,以保证铜环与电缆内导体芯线和内层屏蔽层可靠连接,通过钢环边沿与不锈钢壳体前段无螺纹处进行圆周激光焊接为一整体结构,从而让保证了涡流传感器长时间工作稳定性、可靠性、安全性。(An eddy current probe and a manufacturing method thereof comprise a cable and an outer sleeve piece, wherein the end part of the cable is respectively provided with a first copper ring, a second copper ring and a third copper ring; the outer surface of the copper ring is coated with a packaging shell, the surface of the packaging shell is respectively provided with a first wire passing groove and a second wire passing groove, the end part of the packaging shell is provided with a coil mounting seat, the outer surface of the coil mounting seat is fixedly wound with a coil, the outer surface of the packaging shell is provided with a limiting bulge, a threaded sleeve is sleeved between the limiting bulge and the coil mounting seat, the outer surface of the threaded sleeve is connected with a stainless steel shell through threads, and the outer surface of the stainless steel shell is connected with an inner cavity of the outer shell. The invention overcomes the defects of the prior art, the first copper ring and the second copper ring are used as media to ensure that the copper rings are reliably connected with the conductor core wire and the inner shielding layer of the cable, and the edge of the steel ring and the front section of the stainless steel shell are welded into an integral structure by circumferential laser, so that the long-time working stability, reliability and safety of the eddy current sensor are ensured.)

1. An eddy current probe, characterized in that: the cable comprises a cable (1) and an outer sleeve part (10), wherein a first copper ring (2), a second copper ring (3) and a third copper ring (4) are respectively arranged at the end part of the cable (1), and the first copper ring (2), the second copper ring (3) and the third copper ring (4) are respectively and fixedly connected to the outer surface of an inner conductor core wire, the outer surface of an inner shielding layer and the outer surface of an outer shielding layer of the cable (1); the outer surfaces of the first copper ring (2), the second copper ring (3) and the third copper ring (4) are coated with a packaging shell (5), the surface of the packaging shell (5) is respectively provided with a first wire passing groove (6) and a second wire passing groove (7), the first wire passing groove (6) and the second wire passing groove (7) respectively correspond to the outer surface of the first copper ring (2) and the outer surface of the second copper ring (3), the end part of the packaging shell (5) is provided with a coil mounting seat (8), the outer surface of the coil mounting seat (8) is fixedly wound with a coil (9), and leads at two ends of the coil (9) respectively penetrate through the first wire passing groove (6) and the second wire passing groove (7) to be connected with the first copper ring (2) and the second copper ring (3);

the outer surface of the packaging shell (5) is provided with a limiting bulge (11), a threaded sleeve (12) is fixedly sleeved between the limiting bulge (11) and the coil mounting seat (8), the first wire passing groove (6) and the second wire passing groove (7) are both positioned in the threaded sleeve (12), the outer surface of the threaded sleeve (12) is connected with an internal thread of a stainless steel shell (13) through threads, and the outer surface of the stainless steel shell (13) is connected with an inner cavity of an outer shell (14) through external threads;

the outer sleeve piece (10) is sleeved on the outer surface of the coil mounting seat (8), and the end part of the outer sleeve piece (10) is fixedly connected with the outer shell (14) through a steel ring (15).

2. An eddy current probe according to claim 1, wherein: the thread sleeve (12) is coated on the outer surface of the packaging shell (5) by adopting a high-temperature full-sealing injection molding process.

3. An eddy current probe according to claim 2, wherein: the external screw thread of thread bush (12) sets up to 10 tapering structures, the internal thread of stainless steel casing (13) sets up to 10 tapering internal threads, the internal thread of stainless steel casing (13) cooperatees with the external screw thread of thread bush (12) and locks fixedly.

4. An eddy current probe according to claim 3, wherein: annular groove (16) have been seted up to stainless steel casing (13) surface, annular groove (16) inside is provided with two round holes that each other become 180 degrees, install the check pin in the round hole, the check pin passes the round hole and locks mutually with thread bush (12).

5. An eddy current probe according to claim 1, wherein: two wire passing holes are formed in the coil mounting seat (8), and leads at two ends of the coil (9) respectively penetrate through the two wire passing holes and then are connected with the first copper ring (2) and the second copper ring (3) through the first wire passing groove (6) and the second wire passing groove (7).

6. An eddy current probe according to claim 1, wherein: the inner cavity side surface of the outer sleeve piece (10) is provided with a positioning groove, and the outer sleeve piece (10) is connected with the coil mounting seat (8) through the positioning groove.

7. An eddy current probe according to claim 6, wherein: two groups of annular grooves (18) are formed in the outer surface of the steel ring (15), annular connecting protrusions are arranged on the inner side surface of the outer sleeve piece (10) and the inner surface of the end portion of the outer shell (14), and the annular connecting protrusions are welded in the two groups of annular grooves (18) through laser respectively.

8. An eddy current probe according to claim 1, wherein: a sealing groove (19) is formed in the outer surface of the stainless steel shell (13), a sealing ring (20) is fixedly mounted in the sealing groove (19), and the stainless steel shell (13) is in sealing contact with the inner surface of the outer sleeve piece (10) through the sealing ring (20).

9. A method of manufacturing an eddy current probe according to any one of claims 1 to 8, wherein: the method comprises the following steps:

step S1: the diameter of an inner ring hole, the diameter of an outer ring, the number of turns of a coil, the thickness of the coil, direct current resistance, inductance, loss and quality factor of the coil (9) are adjusted as required;

step S2: respectively crimping a first copper ring (2), a second copper ring (3) and a third copper ring (4) on the outer surface of an inner conductor core wire, the outer surface of an inner shielding layer and the outer surface of an outer shielding layer of the cable (1);

step S3: placing the cable wire with the copper ring and the polyphenylene sulfide particle material prepared in the step S2 into a customized plastic mold, and enabling the polyphenylene sulfide particle material to be injected into an integrated structure of a packaging shell (5) and a coil mounting seat (8), so that the packaging shell (5) is coated on the outer surface of the cable (1);

step S4: placing the coil (9) debugged in the step S1 on the plane of the coil mounting seat (8) formed by injection molding in the step S3, and connecting the two ends of the lead of the coil (9) with the first copper ring (2) and the second copper ring (3) in a spot welding manner through a first wire passing groove (6) and a second wire passing groove (7) which are formed by injection molding on the surface of the packaging shell (5);

step S5: putting the parts formed in the step S4 into an injection mold of the thread bush (12) together, and enabling the thread bush (12) formed by injection molding to be tightly wrapped on the outer surface of the packaging shell (5);

step S6: placing the part formed in the step S5 and the steel ring (15) into a mold of an outer sleeve piece (10) for injection molding to form a structure of the outer sleeve piece (10), and enabling the outer sleeve piece (10) and one end of the steel ring (15) to be in an integral structure by injection molding;

step S7: screwing the external thread part of the thread sleeve (12) into the internal thread of the stainless steel shell (13) for sensitivity adjustment, and testing the screwing depth by a special static displacement calibration instrument until the output sensitivity of the sensor reaches the designed 0.787V/mm;

step S8: after the sensitivity is adjusted, namely the position of the thread sleeve (12) screwed into the internal thread of the stainless steel shell (13) is determined, the overlapping contact position of the outer ring of the steel ring (15) and the outer shell (14) is subjected to laser seamless precision welding along the circumference to form an integral structure.

Technical Field

The invention relates to the technical field of eddy current probes, in particular to an eddy current probe and a manufacturing method thereof.

Background

The most typical application of 25mm diameter eddy current probe is in large turbines to monitor thermal expansion or cooling shrinkage of the cylinder and rotor during start-up heating or shutdown cooling of the turbine and during load changes. Because the heated area of the rotor is larger than that of the cylinder, the mass of the rotor is smaller than that of the corresponding cylinder, and the heat release coefficient of steam on the rotor surface is larger, under the same condition, the temperature of the rotor changes faster than that of the cylinder, expansion difference exists between the rotor and the cylinder, and the difference is that the rotor is relative to the cylinder, an eddy current sensor probe with the diameter of 25mm is usually fixed on the inner side of the cylinder by a firm support, and the probe monitors the displacement change generated by the rotor disc in a non-contact mode.

At present, the traditional eddy current probe is manufactured by adhering a shaped coil and a common plastic skeleton together by glue, and then fixing the coil end on a cable, so that the assembly gap is large and the size precision is not high. When the probe is used in a working temperature environment and a vibration environment of more than 100 ℃ for a long time under certain physical impact, the coil is easy to shift and loosen, so that the probe is unstable and unreliable in work. And the two ends of the lead of the probe coil are connected with the inner conductor and the inner shielding layer of the coaxial cable by adopting tin wires for welding, and the product manufactured by the probe coil connecting method is easy to oxidize and desolder at a soldering joint when used in a high-temperature environment for a long time, thereby causing the damage of the probe. And after the coil and the coil supporting framework are arranged in the protective cover, only 0.15-0.2 mm of gaps are reserved between the inner wall of the protective cover and the outer edges of the coil and the coil supporting framework, so that less epoxy glue can permeate into the gaps, and when the protective cover works in a high-temperature and vibration environment for a long time, the inner wall of the periphery of the protective cover can be separated from the thin and thin adhesive epoxy glue, so that the coil is displaced and loosened. And because there is not any locking connection structure between stainless steel casing inner wall and front end, and the coil support skeleton of coil bonding, only fill them fixedly through the epoxy glue, when the product works in the environment of higher temperature, greasy dirt and vibration for a long time, stainless steel casing inner wall can separate with the epoxy glue, lead to the probe head body to take place to shift, become flexible, cause the probe to work unstably, unreliable.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the eddy current probe and the manufacturing method thereof, which overcome the defects of the prior art, have reasonable design, use the first copper ring and the second copper ring as media, ensure that the inner conductor core wire and the inner shielding layer of the cable can be in large-area contact with the copper ring so as to ensure that the copper ring can be reliably connected with the inner conductor core wire and the inner shielding layer of the cable, and carry out circumferential laser welding on the unthreaded part at the front section of the stainless steel shell through the edge of the steel ring to form an integral structure, thereby ensuring the long-time working stability, reliability and safety of the eddy current sensor.

In order to achieve the purpose, the invention is realized by the following technical scheme:

the invention discloses an eddy current probe, which comprises a cable and an outer sleeve part, wherein the end part of the cable is respectively provided with a first copper ring, a second copper ring and a third copper ring, and the first copper ring, the second copper ring and the third copper ring are respectively and fixedly connected with the outer surface of an inner conductor core wire, the outer surface of an inner shielding layer and the outer surface of an outer shielding layer of the cable; the outer surfaces of the first copper ring, the second copper ring and the third copper ring are wrapped with a packaging shell, the surface of the packaging shell is respectively provided with a first wire passing groove and a second wire passing groove, the first wire passing groove and the second wire passing groove respectively correspond to the outer surface of the first copper ring and the outer surface of the second copper ring, the end part of the packaging shell is provided with a coil mounting seat, the outer surface of the coil mounting seat is fixedly wound with a coil, and leads at two ends of the coil respectively penetrate through the first wire passing groove and the second wire passing groove to be connected with the first copper ring and the second copper ring;

the outer surface of the packaging shell is provided with a limiting bulge, a threaded sleeve is fixedly sleeved between the limiting bulge and the coil mounting seat, the first wire passing groove and the second wire passing groove are both positioned in the threaded sleeve, the outer surface of the threaded sleeve is connected with an internal thread of the stainless steel shell through a thread, and the outer surface of the stainless steel shell is connected with an inner cavity of the outer shell through an external thread;

the outer sleeve is sleeved on the outer surface of the coil mounting seat, and the end part of the outer sleeve is fixedly connected with the outer shell through a steel ring.

Preferably, the threaded sleeve is coated on the outer surface of the packaging shell by adopting a high-temperature full-sealed injection molding process.

Preferably, the external thread of the thread bush is set to be a 10-degree taper structure, the internal thread of the stainless steel shell is set to be a 10-degree taper internal thread, and the internal thread of the stainless steel shell is matched with the external thread of the thread bush to be locked and fixed.

Preferably, the outer surface of the stainless steel shell is provided with an annular groove, two round holes which are 180 degrees away from each other are formed in the annular groove, a locking nail is installed in each round hole, and the locking nail penetrates through each round hole to be locked with the threaded sleeve.

Preferably, two wire passing holes are formed in the coil mounting seat, and leads at two ends of the coil respectively penetrate through the two wire passing holes and then are connected with the first copper ring and the second copper ring through the first wire passing groove and the second wire passing groove.

Preferably, the inner cavity side surface of the outer sleeve member is provided with a positioning groove, and the outer sleeve member is connected with the coil mounting seat through the positioning groove.

Preferably, two groups of annular grooves are formed in the outer surface of the steel ring respectively, annular connecting protrusions are arranged on the inner side surface of the outer sleeve piece and the inner surface of the end part of the outer shell, and the annular connecting protrusions are welded in the two groups of annular grooves through laser respectively.

Preferably, a sealing groove is formed in the outer surface of the stainless steel shell, a sealing ring is fixedly mounted in the sealing groove, and the stainless steel shell is in sealing contact with the inner surface of the outer sleeve piece through the sealing ring.

The invention also discloses a manufacturing method of the eddy current probe, which comprises the following steps:

step S1: the diameter of an inner ring hole, the diameter of an outer ring, the number of turns of a coil, the thickness of the coil, direct current resistance, inductance, loss and quality factor of the coil are adjusted as required;

step S2: respectively crimping a first copper ring, a second copper ring and a third copper ring on the outer surface of an inner conductor core wire, the outer surface of an inner layer shielding layer and the outer surface of an outer layer shielding layer of the cable;

step S3: placing the cable wire with the copper ring and the polyphenylene sulfide particle material prepared in the step S2 into a customized plastic mold, and injecting the polyphenylene sulfide particle material into an integrated structure of a packaging shell and a coil mounting seat, so that the packaging shell is coated on the outer surface of the cable;

step S4: placing the coil debugged in the step S1 on the plane of the coil mounting seat formed by injection molding in the step S3, and connecting the two ends of the lead of the coil with the first copper ring and the second copper ring through the first wire passing groove and the second wire passing groove formed by injection molding on the surface of the packaging shell in a spot welding manner;

step S5: putting the parts formed in the step S4 into an injection mold of the thread bush together, so that the thread bush formed by injection molding is tightly wrapped on the outer surface of the packaging shell;

step S6: placing the part formed in the step S5 and the steel ring into a mold of an outer sleeve piece together for injection molding to form an outer sleeve piece structure, and enabling the outer sleeve piece and one end of the steel ring to be in an integral structure through injection molding;

step S7: screwing the external thread part of the thread sleeve into the internal thread of the stainless steel shell for sensitivity adjustment, and testing the screwing depth by a special static displacement calibration instrument until the output sensitivity of the sensor reaches the designed 0.787V/mm;

step S8: after the sensitivity is adjusted, namely the position of the thread bush screwed into the internal thread of the stainless steel shell is determined, laser seamless precision welding is carried out on the coincident contact position of the outer ring of the steel ring and the outer shell along the circumference to form an integral structure.

The invention provides an eddy current probe and a manufacturing method thereof. The method has the following beneficial effects: the first copper ring, the second copper ring and the third copper ring are respectively and fixedly connected to the outer surface of an inner conductor core wire, the outer surface of an inner layer shielding layer and the outer surface of an outer layer shielding layer of the cable; use first copper ring and second copper ring as the medium, make cable inner conductor heart yearn and inlayer shielding layer can with the large tracts of land contact of copper ring to at copper ring surface cladding encapsulation casing, with guarantee that copper ring and cable inner conductor heart yearn and inlayer shielding layer can reliably be connected, thereby also can guarantee that the junction is difficult to the oxidation under high temperature environment and drops, and then can effectively guarantee reliably to connect the transmission signal. The internal thread through with the stainless steel casing sets up to carrying out tapering sealing connection with the external thread of thread bush, rather than the smooth connection of free state to can prevent that the greasy dirt from afterbody infiltration, also can further guarantee fixed not shifting, not hard up, the not oxidation of probe coil simultaneously, can effectively guarantee the stability and the reliability of probe long-time work. And the steel ring edge and the front section of the stainless steel shell are subjected to circumferential laser welding to form an integral structure, so that the long-time working stability, reliability and safety of the eddy current sensor are ensured.

Drawings

In order to more clearly illustrate the present invention or the prior art solutions, the drawings that are needed in the description of the prior art will be briefly described below.

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural diagram of a cable according to the present invention connected to a first copper ring, a second copper ring and a third copper ring;

FIG. 3 is a schematic view of the mounting structure of the package housing and the coil mounting base according to the present invention;

FIG. 4 is a schematic view showing an installation structure of the thread bush according to the present invention;

FIG. 5 is a schematic cross-sectional view of a stainless steel case according to the present invention;

FIG. 6 is a schematic cross-sectional view of a steel ring according to the present invention;

FIG. 7 is a schematic view showing an installation structure of the outer case of the present invention;

the reference numbers in the figures illustrate:

1. a cable; 2. a first copper ring; 3. a second copper ring; 4. a third copper ring; 5. a package housing; 6. a first wire passing groove; 7. a second wire passing groove; 8. a coil mounting seat; 9. a coil; 10. an outer sleeve member; 11. a limiting bulge; 12. a threaded sleeve; 13. a stainless steel housing; 14. an outer housing; 15. a steel ring; 16. an annular groove; 18. an annular groove; 19. a sealing groove; 20. and (5) sealing rings.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings.

In a first embodiment, as shown in fig. 1 to 7, the present invention discloses an eddy current probe, which includes a cable 1 and an outer sleeve 10, wherein the end of the cable 1 is respectively provided with a first copper ring 2, a second copper ring 3 and a third copper ring 4, and the first copper ring 2, the second copper ring 3 and the third copper ring 4 are respectively and fixedly connected to the outer surface of an inner conductor core wire, the outer surface of an inner shielding layer and the outer surface of an outer shielding layer of the cable 1; the outer surfaces of the first copper ring 2, the second copper ring 3 and the third copper ring 4 are coated with a packaging shell 5, the surface of the packaging shell 5 is respectively provided with a first wire passing groove 6 and a second wire passing groove 7, the first wire passing groove 6 and the second wire passing groove 7 respectively correspond to the outer surface of the first copper ring 2 and the outer surface of the second copper ring 3, the end part of the packaging shell 5 is provided with a coil mounting seat 8, the outer surface of the coil mounting seat 8 is fixedly wound with a coil 9, and leads at two ends of the coil 9 respectively pass through the first wire passing groove 6 and the second wire passing groove 7 to be connected with the first copper ring 2 and the second copper ring 3; in this embodiment, the coil mounting seat 8 is provided with two wire passing holes, and the leads at two ends of the coil 9 respectively pass through the two wire passing holes and then are connected with the first copper ring 2 and the second copper ring 3 through the first wire passing groove 6 and the second wire passing groove 7.

The outer surface of the packaging shell 5 is provided with a limiting bulge 11, a threaded sleeve 12 is fixedly sleeved between the limiting bulge 11 and the coil mounting seat 8, the first wire passing groove 6 and the second wire passing groove 7 are both positioned in the threaded sleeve 12, the outer surface of the threaded sleeve 12 is connected with an internal thread of a stainless steel shell 13 through a thread, and the outer surface of the stainless steel shell 13 is connected with an inner cavity of an outer shell 14 through an external thread;

a positioning groove is formed in the inner cavity side surface of the outer sleeve member 10, and the outer sleeve member 10 is connected with the coil mounting seat 8 through the positioning groove; the end of the outer jacket element 10 is fixedly connected to the outer housing 14 by means of a steel ring 15.

The working principle is as follows:

the invention is characterized in that a first copper ring 2, a second copper ring 3 and a third copper ring 4 are respectively and fixedly connected with the outer surface of an inner conductor core wire, the outer surface of an inner layer shielding layer and the outer surface of an outer layer shielding layer of a cable 1; the first copper ring 2 and the second copper ring 3 are used as media, so that an inner conductor core wire and an inner shielding layer of the cable 1 can be in large-area contact with the copper rings, the outer surfaces of the copper rings are coated with the packaging shell 5 to ensure that the copper rings can be reliably connected with the inner conductor core wire and the inner shielding layer of the cable, the connection position can be ensured not to be easily oxidized and fall off under a high-temperature environment, the reliable connection and signal transmission can be effectively ensured, then two ends of a lead wire of the coil 9 are respectively welded on the first copper ring 2 and the second copper ring 3 by adopting laser spot welding, and the outer surfaces of the copper rings are coated with the threaded sleeve 12 for fixed positioning, and in the embodiment, the threaded sleeve 12 is coated on the outer surface of the packaging shell 5 by adopting a high-temperature full-sealing injection molding process; thereby further ensuring that the two ends of the coil lead are reliably connected with the coaxial cable. Therefore, the stability, reliability and safety performance of the eddy current sensor probe of the traditional eddy current sensing probe are effectively ensured; the temperature drift performance of the sensor probe is greatly reduced; because of the totally-sealed non-oxidation forming, the service life of the probe can be prolonged to more than 10 years from three years of the traditional production process.

In the second embodiment, as a further improvement of the first embodiment, the external thread of the threaded sleeve 12 is set to be a 10 ° taper structure, the internal thread of the stainless steel shell 13 is set to be a 10 ° taper internal thread, and the internal thread of the stainless steel shell 13 is matched with the external thread of the threaded sleeve 12 for locking and fixing. The internal thread of the stainless steel shell 13 and the external thread of the thread sleeve 12 are set to be in taper sealing connection instead of smooth connection in a free state, so that oil stains can be prevented from permeating from the tail, the probe coil can be further fixed without displacement, loosening and oxidation, and the stability and reliability of long-time work of the probe can be effectively guaranteed.

In the third embodiment, as a further improvement of the second embodiment, an annular groove 16 is formed in the outer surface of the stainless steel shell 13, two circular holes which are 180 degrees away from each other are formed in the annular groove 16, a locking nail is installed in each circular hole, and the locking nail penetrates through the circular holes to be locked with the threaded sleeve 12. The stainless steel shell 13 and the threaded sleeve 12 are further tightly locked and connected into a whole through the locking nail.

In a fourth embodiment, as a further improvement of the second embodiment, two sets of annular grooves 18 are respectively formed in the outer surface of the steel ring 15, and annular connecting protrusions are respectively formed on the inner side surface of the outer sleeve 10 and the inner surface of the end portion of the outer casing 14 and are respectively welded in the two sets of annular grooves 18 by laser. The annular groove 18 is used to increase the contact area between the steel ring 15 and the outer sleeve member 10 and the outer casing 14, thereby further ensuring the stability of the connection between the outer sleeve member 10 and the outer casing 14.

In a fifth embodiment, as a further improvement of the second embodiment, a sealing groove 19 is formed in an outer surface of the stainless steel casing 13, a sealing ring 20 is fixedly installed in the sealing groove 19, and the stainless steel casing 13 is in sealing contact with an inner surface of the outer sleeve 10 through the sealing ring 20. The sealing effect inside the outer sleeve 10 is ensured by the sealing ring 20.

The invention also discloses a manufacturing method of the eddy current probe, which comprises the following steps:

step S1: the diameter of an inner ring hole, the diameter of an outer ring, the number of turns of a coil, the thickness of the coil, direct current resistance, inductance, loss and quality factor of the coil 9 are adjusted as required;

step S2: respectively crimping a first copper ring 2, a second copper ring 3 and a third copper ring 4 on the outer surface of an inner conductor core wire, the outer surface of an inner layer shielding layer and the outer surface of an outer layer shielding layer of the cable 1;

step S3: placing the cable wire with the copper ring and the polyphenylene sulfide particle material prepared in the step S2 into a customized plastic mold, and injecting the polyphenylene sulfide particle material into an integrated structure of the packaging shell 5 and the coil mounting seat 8, so that the packaging shell 5 is coated on the outer surface of the cable 1; therefore, the probe coil can be fixedly positioned without moving or loosening, and the stability and reliability of signal transmission can be ensured;

step S4: placing the coil 9 debugged in the step S1 on the plane of the coil mounting seat 8 formed by injection molding in the step S3, and connecting the two ends of the lead of the coil 9 with the first copper ring 2 and the second copper ring 3 through the first wire passing groove 6 and the second wire passing groove 7 formed by injection molding on the surface of the packaging shell 5 in a spot welding manner;

step S5: putting the parts formed in the step S4 into an injection mold of the threaded sleeve 12 together, so that the threaded sleeve 12 formed by injection molding is tightly wrapped on the outer surface of the packaging shell 5; the coil core structure block and the cable structure body can be tightly and firmly fixed together, and the polyphenylene sulfide material can also reliably fix the 3 copper rings and the cable together through injection molding. A thread structure is formed on the injection molding structure body and is used for precisely adjusting the sensitivity when the injection molding structure body is in threaded connection with the inside of the stainless steel shell at the back;

step S6: placing the part formed in the step S5 and the steel ring 15 into a mold of the outer sleeve 10 for injection molding to form the structure of the outer sleeve 10, and injecting the outer sleeve 10 and one end of the steel ring 15 into an integral structure; the connection with the stainless steel shell of the probe is convenient;

step S7: screwing the external thread part of the thread sleeve 12 into the internal thread of the stainless steel shell 13 for sensitivity adjustment, and testing the screwing depth by a special static displacement calibration instrument until the output sensitivity of the sensor reaches the designed 0.787V/mm;

step S8: after the sensitivity is adjusted, namely the position of the thread bush 12 screwed into the internal thread of the stainless steel shell 13 is determined, laser seamless precision welding is carried out on the superposed contact position of the outer ring of the steel ring 15 and the outer shell 14 along the circumference to form an integral structure.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.