Aerodynamic high-precision inductance displacement sensor

Abstract

The application discloses a kind of pneumatic high-precision inductance displacement sensors, belongs to geometric quantity calibration field.The application includes probe head assembly, guide assembly, reset component, coil assembly, pneumatic assembly;Probe head assembly is installed at the bottom of guide assembly, and carries out spherical surface contact with the measured piece;Guide assembly realizes the function of guiding and air tightness;Spring force generated by reset component makes guide rod not rotate along axial movement, guarantee that standard probe head and measured surface are in full contact, and realize high-precision reset;Coil assembly converts displacement into inductance, realizes the output and conversion of displacement;Pneumatic assembly forms air cavity, guide rod moves upward when external gas supply, guide rod moves downward under the action of reset component after external gas supply is disconnected.The application is a kind of automatic reciprocating motion, high-precision, suitable for automatic measurement inductance displacement sensor, in 0~100 μm micro-displacement high-precision measurement, measurement repeatability reaches 10nm.

Description

Technical Field

[0001] The invention relates to a pneumatic high-precision inductive displacement sensor, belonging to the field of geometric quantity calibration. Background Art

[0002] An inductive displacement sensor is a device based on the principle of electromagnetic induction that detects displacement by changes in coil inductance. It has a simple and reliable structure and high measurement accuracy, making it widely used in fields such as micro-displacement measurement. In particular, in gauge block calibration, when the comparison method is used to calibrate gauge blocks, an inductive displacement sensor is usually used to measure the length difference between the measured block and the standard gauge block.

[0003] During gauge block comparison measurements, a high-precision inductive displacement sensor is mounted vertically on the gauge block comparator. Traditional inductive displacement sensors require a fork or other lifting mechanism to be installed on the probe. Manually moving the fork allows the sensor guide rod to move up and down, contacting the piece being measured and acquiring the measured value. For example, when placing or changing the gauge block's position, the fork must be manually pressed to lift the probe. After placing the gauge block at the location to be tested, the fork must be manually moved repeatedly to ensure full contact between the probe and the block being measured. Once the reading stabilizes, the current value can be acquired. Once the gauge block has been verified, the fork must be pressed again to lift the sensor probe and remove the block being measured. Traditional high-precision inductive displacement sensors use a manually-activated shift fork to cause the measuring rod to reciprocate for measurement. This method has the following main disadvantages: First, the force of the shift fork is difficult to control and the consistency of the force is difficult to ensure. Excessive force will cause tiny, irreversible changes in the installation position of the sensor probe, thereby affecting the results of the comparative measurement; if the force is too small, dust and other foreign matter may prevent the probe from fully contacting the object being measured, affecting the measurement results. Therefore, it places high demands on the operator and requires long-term professional training before operation; second, the traditional manual shift fork method is not suitable for automated measurement, and efficiency is difficult to improve.

[0004] Currently, pneumatic displacement sensors available on the market from commercial companies such as Switzerland's TESA, Germany's Heidenhain, and Shenzhen Shensijun have a repeatability of 100nm. However, the accuracy of this type of sensor is not enough to meet the comparative measurement needs of second-class gauge blocks and third-class gauge blocks. For example, a Chinese patent with publication number CN105953717B discloses a pneumatic displacement sensor structure, which includes an outer tube and a small cylinder assembly. The outer diameter of the outer tube is less than or equal to 20 mm. The air inlet end and the circular probe of the small cylinder are respectively located at the two ends of the outer tube. The small cylinder assembly also includes a positioning assembly, an iron core, an axis core, a long shaft and a track. The air inlet end is connected to the track. A circular probe is fixed at one end of the long shaft, and an iron core is fixed at the other end. The long shaft performs reciprocating telescopic motion in the track. The axis core is freely accommodated in the track and is in active contact with the iron core. The direction of the long shaft is fixed by the positioning pin of the positioning assembly. When working, a working air pressure of 0.15 MPa to 0.7 MPa is provided to the track to drive the long shaft to reciprocate, thereby measuring the flatness of the object surface by measuring the change in displacement. The device fixes the long shaft by setting a positioning assembly to prevent it from offset. For example, a Chinese patent with publication number CN210603168U discloses a pneumatic displacement sensor, comprising: an outer tube; a rear end cover connected to a gas transmission device at the rear end of the outer tube, the rear end cover being provided with an air outlet; a frame mounted inside the outer tube, one end of the frame being provided with an air inlet pipe that is sealed and plugged into the air outlet, and a coil assembly wound around the frame; a detection assembly that can move back and forth along the axial direction of the outer tube, one end of the detection assembly extending outside the outer tube for detecting the displacement of the object to be measured, and the other end inserted into the coil assembly inside the frame to cooperate with the coil assembly to generate an induced electromotive force when moving along the axial direction. The device achieves guidance by adding a strip groove to the front end cover sleeve as a guide for the shaft positioning pin to prevent the rotation of the moving parts of the shaft connecting rod iron core. The basic principle of achieving positioning and guidance in existing pneumatic displacement sensors is pin hole positioning, which can improve measurement accuracy to a certain extent, but the positioning accuracy is difficult to improve. The measurement accuracy that can be achieved is on the micron level, which cannot meet the measurement requirements of higher precision. Summary of the Invention

[0005] The object of the present invention is to provide a pneumatic high-precision inductive displacement sensor which has automatic reciprocating motion, high precision and is suitable for automated measurement.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A pneumatic high-precision inductive displacement sensor of the present invention comprises: a probe assembly, a guide assembly, a reset assembly, a coil assembly, and a pneumatic assembly;

[0008] The probe assembly includes: a standard probe, a probe locking nut and a standard probe adapter cap;

[0009] The guide assembly includes: a guide rod, a lower dense ball bearing, a lower dense ball bearing chuck, an upper dense ball bearing, an upper dense ball bearing chuck and an outer cylinder;

[0010] The reset assembly includes: a lower circular spring, an outer chuck of the lower circular spring, an inner chuck of the lower circular spring, an upper circular spring, an outer chuck of the upper circular spring, an inner chuck of the upper circular spring, a reset spring, a reset spring adjustment nut mounting seat and a reset spring adjustment nut;

[0011] The coil assembly includes: a magnetic tank mounting base, a magnetic tank connecting guide rod, a lower magnetic tank, a coil and an upper magnetic tank;

[0012] The pneumatic assembly includes: a micro air pipe joint, an air cavity sealing cover, an outer chuck of a lower circular spring piece, and an inner chuck of a lower circular spring piece;

[0013] The connection dimensions of the standard probe in the probe assembly comply with the provisions of GB / T 26094-2010 "Inductive Micrometer". The standard probe is connected to the guide rod via the standard probe adapter cap, making it easy to replace the standard probe according to the type of the measured surface. The probe is then tightened with the probe lock nut to prevent the standard probe from loosening.

[0014] The guide rod is an integrated structure, and an integrated piston column is designed at the bottom of the guide rod, which cooperates with the inner cylindrical surface of the chuck in the lower circular spring piece in the pneumatic assembly to form an air cavity. The upper and lower ends of the outer cylinder are respectively installed with the upper and lower dense ball bearings for guidance. The upper and lower dense ball bearings use precision balls as guide parts, and the precision balls are kept evenly distributed by the embedded ball retainer. The upper and lower dense ball bearings are installed and clamped by the upper and lower dense ball bearing chucks respectively. The inner hole of the outer cylinder adopts a precision grinding process to ensure the coaxiality of the installation positions of the upper and lower dense ball bearings;

[0015] The reset assembly adopts double circular spring plates to increase the rebound stiffness, and adopts a clearance reverse adjustment threaded disk to adjust the stroke of the guide rod and the reverse locking during transportation; the upper circular spring plate and the lower circular spring plate adopt a circular structure, the inner ring spring of the upper circular spring plate is connected to the guide rod through the inner chuck of the upper circular spring plate, the outer ring spring of the upper circular spring plate is connected to the outer cylinder through the outer chuck of the upper circular spring plate, the inner ring spring of the lower circular spring plate is connected to the step surface on the guide rod through the inner chuck of the lower circular spring plate, and the outer ring spring of the lower circular spring plate is contacted and connected with the step surface on the outer cylinder through the outer chuck of the lower circular spring plate, and the material of the upper circular spring plate and the lower circular spring plate is elastic material; the reverse clearance adjustment disk is installed in the air cavity sealing cover by threading, and the step at the front end of the guide rod is pushed by rotation adjustment to make the guide rod move up and down, thereby adjusting the stroke of the guide rod, and reverse adjustment can make the upper and lower magnetic tanks fit together, thereby ensuring reverse locking during transportation;

[0016] The upper magnetic tank in the coil assembly is connected to the magnetic tank mounting seat, the magnetic tank mounting seat is connected to the outer cylinder, the coil is bonded to the upper magnetic tank, the lower magnetic tank is connected to the magnetic tank connecting guide rod, the magnetic tank connecting guide rod is mounted on the guide rod, the guide rod moves up and down to drive the lower magnetic tank on the magnetic tank connecting guide rod to move, so that the gap between the lower magnetic tank and the upper porcelain tank changes, resulting in a change in inductance, the assembly coaxiality of the upper magnetic tank and the lower magnetic tank is better than 20μm, so as to improve the linearity of the inductance change, the coil cover is mounted on the outside of the magnetic tank mounting seat with an integrated structure and metal material to prevent external magnetic interference, preferably hard aluminum material, the lower magnetic tank and the magnetic tank connecting guide rod are fixed with pin holes and glued to ensure the rigidity of the installation;

[0017] In the pneumatic assembly, the air cavity sealing cover and the outer chuck of the lower circular spring piece together form an air cavity, and the inner chuck of the lower circular spring piece is connected to the guide rod to form a piston. When the guide rod moves up and down, the inner chuck of the lower circular spring piece is driven to move up and down to change the air pressure in the air cavity;

[0018] The probe assembly is installed at the bottom of the guide assembly and makes spherical contact with the measured part. The guide assembly uses a ball bearing to guide the guide rod, thereby increasing the guiding accuracy and structural stability, and ensuring that the guide rod and the inner cylindrical surface of the chuck in the lower circular spring piece in the pneumatic assembly meet the airtightness requirements. The reset assembly generates a reset force to make the guide rod move axially while ensuring that the guide rod does not rotate, ensuring that the standard probe is in full contact with the measured surface and has a high reset accuracy. The coil assembly is used to convert the displacement of the reciprocating motion of the guide rod into inductance, thereby realizing the output and conversion of the displacement. The pneumatic assembly and the piston column on the guide rod form an air cavity. When external air is supplied, the guide rod moves upward under the action of air pressure. After the air is cut off, the guide rod moves downward under the action of the reset assembly.

[0019] Beneficial effects:

[0020] 1. A pneumatic high-precision inductive displacement sensor of the present invention forms an air cavity through an air cavity sealing cover and an outer chuck of a lower circular spring piece, and the inner chuck of the lower circular spring piece is connected to a guide rod to form a piston, and an air pipe joint is led out at the air cavity. After the external air source is connected, the guide rod is driven up and down by changing the air pressure inside the air cavity. No external lifting mechanism such as a fork is required. Under the action of compressed air, the guide rod is driven upward. When the compressed air pressure is released, the guide rod moves downward under the action of a reset spring. The action of the sensor only needs to be controlled by on and off of the compressed air. The operation is convenient and easy to integrate automatically. By adjusting the pressure of the compressed air, the measuring force is adjusted to an appropriate size, avoiding the adverse effects caused by uneven measuring force of the fork. The force of the pneumatic drive method acts evenly on the piston, and the direction of the force is consistent with the direction of movement, avoiding the influence of the radial force generated when the fork is moved on the measurement accuracy.

[0021] 2. The pneumatic high-precision inductive displacement sensor of the present invention uses ball bearings as guide mechanisms at the upper and lower ends. The coaxiality of the upper and lower ball bearing installation positions is better than 5μm, ensuring that the guide displacement is within 0 to 100μm, the straightness change is less than 0.2μm, and the offset of the guide rod during reciprocating motion is extremely small, thereby improving measurement accuracy. The use of ball bearings for guidance reduces the resistance of the guide rod during movement, thereby improving sensor performance.

[0022] 3. The pneumatic high-precision inductive displacement sensor of the present invention adopts a reset method combining double circular springs and a reset spring. The reset spring is installed directly below the lower magnetic tank to generate a spring force along the axial direction of the guide rod, ensuring that the guide rod has good rebound performance. Two circular springs with a circular structure are installed at the upper and lower ends respectively to ensure that the guide rod does not rotate when moving up and down, which can effectively improve the measurement accuracy of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a pneumatic high-precision inductive displacement sensor of the present invention;

[0024] In the figure, 1-standard probe, 2-probe locking nut, 3-standard probe adapter cap, 4-gap reverse adjustment threaded disk, 5-micro air pipe connector, 6-air cavity sealing cover, 7-lower circular spring outer chuck, 8-lower circular spring inner chuck, 9-lower circular spring, 10-lower ball bearing chuck, 11-lower ball bearing, 12-guide rod, 13-outer cylinder, 14-upper ball bearing, 15-upper ball bearing chuck, 16-upper circular spring, 17-upper circular spring outer chuck, 17-1 upper circular spring inner chuck, 18-magnetic tank mounting seat, 19-reset spring, 20-reset spring adjustment nut mounting seat, 21-reset spring adjustment nut, 22-magnetic tank connecting guide rod, 23-lower magnetic tank, 24-coil, 25-upper magnetic tank. DETAILED DESCRIPTION

[0025] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0026] Example 1:

[0027] like Figure 1 As shown, a pneumatic high-precision inductive displacement sensor of the present invention includes: a probe assembly, a guide assembly, a reset assembly, a coil assembly, and a pneumatic assembly;

[0028] The probe assembly includes: a standard probe 1, a probe locking nut 2 and a standard probe adapter cap 3;

[0029] The guide assembly includes: a guide rod 12, a lower dense ball bearing 11, a lower dense ball bearing chuck 10, an upper dense ball bearing 14, an upper dense ball bearing chuck 15 and an outer cylinder 13;

[0030] The reset assembly includes: a lower circular spring 9, a lower circular spring outer chuck 7, a lower circular spring inner chuck 8, an upper circular spring 16, an upper circular spring outer chuck 17, an upper circular spring inner chuck 17-1, a reset spring 19, a reset spring adjustment nut mounting seat 20 and a reset spring adjustment nut 21;

[0031] The coil assembly includes: a magnetic tank mounting base 18, a magnetic tank connecting guide rod 22, a lower magnetic tank 23, a coil 24 and an upper magnetic tank 25;

[0032] The pneumatic assembly includes: a micro air pipe connector 5, an air cavity sealing cover 6, an outer chuck of a lower circular spring piece 7 and an inner chuck of a lower circular spring piece 8;

[0033] The connection dimensions of the standard probe 1 in the probe assembly comply with the provisions of GB / T 26094-2010 "Inductive Micrometers". The standard probe 1 is connected to the guide rod 12 via the standard probe adapter cap 3, making it easy to replace the standard probe 1 according to the type of surface being measured. The probe is then tightened with the probe lock nut 2 to prevent the standard probe 1 from loosening.

[0034] The guide rod 12 is an integrated structure. There is a piston column at the bottom of the guide rod 12, which cooperates with the inner cylindrical surface of the chuck 8 of the lower circular spring in the pneumatic component to form an air cavity. The upper and lower ends of the outer cylinder 13 are respectively installed with an upper dense ball bearing 14 and a lower dense ball bearing 11 for guidance. The upper and lower dense ball bearings 14 and 11 use precision balls as guide parts, and the precision balls are kept evenly distributed by the embedded ball retainer. The upper and lower dense ball bearings 14 and 11 are respectively installed and clamped by the upper dense ball bearing chuck 15 and the lower dense ball bearing chuck 7. The inner hole of the outer cylinder 13 adopts a precision grinding process. The coaxiality of the installation position of the upper and lower dense ball bearings 14 and 11 is better than 5μm, and the linearity variation is less than 0.2μm.

[0035] The reset assembly adopts double circular springs to increase the rebound stiffness; the upper circular spring 16 and the lower circular spring 9 adopt a circular structure, the inner ring spring of the upper circular spring 16 is connected to the guide rod 12 through the upper circular spring inner chuck 17-1, the outer ring spring of the upper circular spring 16 is connected to the outer cylinder 13 through the upper circular spring outer chuck 17, the inner ring spring of the lower circular spring 9 is connected to the step surface on the guide rod 12 through the lower circular spring inner chuck 8, and the outer ring spring of the lower circular spring 9 is in contact with the step surface on the outer cylinder 13 through the lower circular spring outer chuck 7. The material of the upper circular spring 16 and the lower circular spring 9 is elastic material; the reverse clearance adjustment disk 4 is installed in the air cavity sealing cover 6 by threading, and the step at the front end of the guide rod 12 is pushed by rotation adjustment to make the guide rod 12 move up and down, thereby adjusting the stroke of the guide rod 12, and the reverse adjustment can make the lower magnetic tank 23 fit with the upper magnetic tank 25, thereby ensuring reverse locking during transportation.

[0036] The upper magnetic tank 25 in the coil assembly is connected to the magnetic tank mounting base 18, which is connected to the outer cylinder 13. The coil 24 is bonded to the upper magnetic tank 25, and the lower magnetic tank 23 is connected to the magnetic tank connecting guide rod 22. The magnetic tank connecting guide rod 22 is mounted on the guide rod 12. The guide rod 12 moves up and down, driving the lower magnetic tank 23 on the magnetic tank connecting guide rod 22 to move, causing the gap between the lower magnetic tank 23 and the upper porcelain tank 25 to change, resulting in a change in inductance. The assembly coaxiality of the upper magnetic tank 25 and the lower magnetic tank 23 is better than 20μm to improve the linearity of the inductance change. The coil cover is made of hard aluminum to prevent external magnetic interference. The installation of the lower magnetic tank 23 and the magnetic tank connecting guide rod 22 is fixed with pin holes and glued to ensure the rigidity of the installation.

[0037] In the pneumatic assembly, the air cavity sealing cover 6 and the lower circular spring outer chuck 7 together form the air cavity, and the lower circular spring inner chuck 8 is connected to the guide rod 12 to form a piston. When the guide rod 12 moves up and down, it drives the lower circular spring inner chuck 8 to move up and down to change the air pressure in the air cavity;

[0038] The probe assembly is installed at the bottom of the guide assembly and makes spherical contact with the workpiece to be measured. The guide assembly adopts upper dense ball bearings 14 and lower dense ball bearings 11 to guide the guide rod 12, thereby increasing the guiding accuracy and structural stability, and ensuring that the guide rod 12 and the inner cylindrical surface of the chuck 8 in the lower circular spring in the pneumatic assembly meet the airtightness requirements. The reset assembly generates a reset force to make the guide rod 12 move axially while ensuring that the guide rod 12 does not rotate, ensuring that the standard probe 1 is in full contact with the measured surface and has high reset accuracy. The coil assembly is used to convert the displacement of the reciprocating motion of the guide rod 12 into inductance, thereby realizing the output and conversion of the displacement. The pneumatic assembly and the piston column on the guide rod 12 form an air cavity. When external air is supplied, the guide rod 12 moves upward under the action of air pressure. After the air is cut off, the guide rod 12 moves downward under the action of the reset assembly.

[0039] The working process of the pneumatic high-precision inductive displacement sensor of the present invention is as follows: external compressed air is connected through a micro air pipe connector 5, a valve is set to control the on-off of the compressed air, and the air pressure of the compressed air is determined by the size of the measuring force of the present invention;

[0040] When the compressed air is turned on, the pressure in the air cavity formed by the air cavity sealing cover 6 and the lower circular spring piece outer chuck 7 increases, driving the piston formed by the lower circular spring piece inner chuck 8 and the guide rod 12 to move upward, driving the standard probe 1 fixedly connected to the guide rod 12 to move upward synchronously. At this time, the standard probe 1 is away from the measured surface to adjust the position of the measured object or replace the measured object. At the same time, the lower magnetic tank 23 fixedly connected to the guide rod 12 also moves upward synchronously, and the fixed connection position of the upper magnetic tank 25, the magnetic tank mounting base 18 and the outer cylinder 13 remains unchanged. Therefore, the distance between the lower magnetic tank 23 and the upper magnetic tank 25 is reduced. When the coil 24 has current, the inductance generated by the coil assembly increases, converting the change in displacement into a change in inductance.

[0041] When the compressed air is released, the guide rod 12 moves downward under the action of the reset spring 19 and the reset assembly, and the standard probe 1 and the lower magnetic can 23 move downward synchronously. The distance between the lower magnetic can 23 and the upper magnetic can 25 increases, and the inductance generated by the coil assembly decreases. When the standard probe 1 contacts the measured surface, the standard probe 1 fully contacts the measured surface under the downward force generated by the reset spring 19 and the reset assembly.

[0042] During the movement of the guide rod 12, the guide assembly ensures that the guide rod 12 moves with high straightness, small offset and small resistance, and the reset assembly ensures that the guide rod 12 does not rotate and has high reset accuracy.

[0043] The above specific description further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pneumatic high-precision inductive displacement sensor, characterized by: include: Probe assembly, guide assembly, reset assembly, coil assembly, pneumatic assembly; The probe assembly includes: a standard probe (1), a probe locking nut (2) and a standard probe adapter cap (3); the guide assembly includes: a guide rod (12), a lower dense ball bearing (11), a lower dense ball bearing chuck (10), an upper dense ball bearing (14), an upper dense ball bearing chuck (15) and an outer cylinder (13); the reset assembly includes: a lower circular spring (9), a lower circular spring outer chuck (7), a lower circular spring inner chuck (8), an upper circular spring (16), an upper circular spring outer chuck ( 17), an upper circular spring inner chuck (17-1), a return spring (19), a return spring adjustment nut mounting seat (20) and a return spring adjustment nut (21); the coil assembly includes: a magnetic tank mounting seat (18), a magnetic tank connecting guide rod (22), a lower magnetic tank (23), a coil (24) and an upper magnetic tank (25); the pneumatic assembly includes: a micro air pipe connector (5), an air cavity sealing cover (6), a lower circular spring outer chuck (7) and a lower circular spring inner chuck (8); The probe assembly is installed at the bottom of the guide assembly and makes spherical contact with the measured object. The guide assembly uses a dense ball bearing to guide the guide rod (12), effectively increasing the guide accuracy and structural stability, ensuring that the guide rod (12) and the inner cylindrical surface of the lower circular spring plate chuck (8) in the pneumatic assembly meet the airtightness requirements. The reset assembly generates a reset force that causes the guide rod (12) to move axially while ensuring that the guide rod (12) does not rotate, ensuring that the standard probe (1) is in full contact with the measured surface and has high reset accuracy. The coil assembly is used to convert the displacement of the reciprocating motion of the guide rod (12) into inductance, thereby realizing the output and conversion of the displacement. The pneumatic assembly and the piston column on the guide rod (12) form an air cavity. When external air is supplied, the guide rod (12) moves upward under the action of air pressure. After the air is cut off, the guide rod (12) moves downward under the action of the reset assembly. The guide rod (12) is an integrated structure. The bottom of the guide rod (12) is in the form of a piston column. The guide rod (12) and the outer cylinder (13) form a piston. The guide rod (12) cooperates with the inner cylindrical surface of the chuck (8) of the lower circular spring in the pneumatic component to form an air cavity. The inner hole of the outer cylinder (13) adopts a precision grinding process. The guide rod (12) is guided to move inside the outer cylinder (13) through the upper dense ball bearing (14) and the lower dense ball bearing (11). The coaxiality of the installation position of the upper dense ball bearing (14) and the lower dense ball bearing (11) is better than 5μm, ensuring that the linearity change of the guide rod (12) is less than 0.2μm within the stroke range. In the pneumatic assembly, the air cavity sealing cover (6) and the lower circular spring piece outer chuck (7) together form the air cavity, and the lower circular spring piece inner chuck (8) is connected to the guide rod (12) to form a piston. When the guide rod (12) moves up and down, it drives the lower circular spring piece inner chuck (8) to move up and down, so that the air pressure in the air cavity changes.

2. The pneumatic high-precision inductive displacement sensor according to claim 1, characterized in that: The connection dimensions of the standard probe (1) in the probe assembly comply with the provisions of GB / T 26094-2010 "Inductive Micrometer". The standard probe (1) is connected to the guide rod (12) through the standard probe adapter cap (3), so that the standard probe (1) can be easily replaced according to the type of the measured surface; and then the probe is tightened by the probe locking nut (2) to prevent the standard probe (1) from loosening.

3. The pneumatic high-precision inductive displacement sensor according to claim 1, characterized in that: The reset assembly adopts a double-circle spring to increase the rebound stiffness; the upper circle spring (16) and the lower circle spring (9) adopt a circular structure, the inner ring spring of the upper circle spring (16) is connected to the guide rod (12) through the upper circle spring inner chuck (17-1), the outer ring spring of the upper circle spring (16) is connected to the outer cylinder (13) through the upper circle spring outer chuck (17), the inner ring spring of the lower circle spring (9) is connected to the step surface on the guide rod (12) through the lower circle spring inner chuck (8), and the outer ring spring of the lower circle spring (9) is connected to the guide rod (12) through the upper circle spring inner chuck (17-1). The outer chuck (7) is in contact with the step surface on the outer cylinder (13) through the lower circular spring piece, and the material of the upper circular spring piece (16) and the lower circular spring piece (9) is an elastic material; the gap reverse adjustment threaded disk (4) is installed in the air cavity sealing cover (6) through the thread, and the step at the front end of the guide rod (12) is pushed by rotation adjustment to make the guide rod (12) move up and down, thereby adjusting the stroke of the guide rod (12). The reverse adjustment can make the lower magnetic tank (23) fit with the upper magnetic tank (25), thereby ensuring reverse locking during transportation.

4. The pneumatic high-precision inductive displacement sensor according to claim 1, characterized in that: In the coil assembly, the coil (24) is bonded to the upper magnetic tank (25) and fixed to the outer cylinder (13) through the magnetic tank mounting seat (18). The lower magnetic tank (23) is fixed to the guide rod (12) through the magnetic tank connecting guide rod (22). The guide rod (12) moves up and down to drive the lower magnetic tank (23) to move, so that the gap between the lower magnetic tank (23) and the upper magnetic tank (25) changes, thereby changing the inductance of the coil (24).

5. The pneumatic high-precision inductive displacement sensor according to claim 4, characterized in that: The assembly coaxiality of the upper magnetic tank (25) and the lower magnetic tank (23) is better than 20 μm to improve the linearity of the inductance change.

6. The pneumatic high-precision inductive displacement sensor according to claim 4, characterized in that: The coil cover is made of metal material to prevent external magnetic interference, and the installation of the lower magnetic tank (23) and the magnetic tank connecting guide rod (22) is fixed by pin holes and coated with glue to ensure the rigidity of the installation.

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