Radial sensor concentricity detection tool and method for magnetic levitation molecular pump

Abstract

This application discloses a concentricity detection fixture and method for a radial sensor of a magnetically levitated molecular pump, belonging to the technical field of concentricity detection. Its key technical features include: a high-precision rotary platform assembly serving as a platform for placing the radial stator assembly under test; the high-precision rotary platform assembly comprising: a V-shaped positioning block, a clamping device, and a precision rotary spindle drive turntable; the V-shaped positioning block and the clamping device are used to fix the radial stator assembly under test on the precision rotary spindle drive turntable; the precision rotary spindle drive turntable is used to drive the radial stator assembly under test to rotate; and a fixture shaft motion control assembly can control the fixture shaft to enter the radial stator assembly under test. Using the technical solution of this application, the concentricity of the upper and lower radial sensors of the radial stator assembly under test can be tested.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of concentricity testing, more particularly, to a magnetic suspension molecular pump radial sensor concentricity detection tool and method. BACKGROUND

[0002] The radial stator assembly is the most critical core component of the magnetic suspension molecular pump, which directly drives the rotor to rotate at high speed. Figure 1 The structure of the radial stator assembly is shown. The radial stator assembly is composed of an upper magnetic bearing 1, an upper radial sensor 2, a lower radial sensor 3, a lower magnetic bearing 4, a stator motor and a bearing seat. The upper and lower radial sensors are mainly used to read the position information of the center of the rotor rotating shaft in real time, and transmit the position signals to the upper and lower magnetic bearings respectively. The accuracy of the position signal reading depends on the concentricity of the upper and lower radial sensors.

[0003] After the installation of the "upper magnetic bearing, lower magnetic bearing, upper radial sensor, lower radial sensor, stator motor and bearing seat", the coaxiality is guaranteed by the inner hole precision of the external bearing seat (about 0.01mm). However, due to the existence of the adjusting positioning slider of the sensor, during the installation of the single sensor in the early stage, the measuring point on the positioning slider is adjusted to be tangent to the inner circle of the sensor, and is fastened by the positioning screw.

[0004] On the one hand, the size precision requirement of the sensor slider is high, and the tightening of the screw will inevitably cause a certain amount of displacement or small angle rotation of the sensor slider.

[0005] On the other hand, after the installation of the two sensors into the finished product, although the upper and lower radial sensors are guaranteed to be coaxial by the inner diameter of the bearing seat, during the installation process, the bearing seat expands after high temperature baking and realizes interference fit with the outer circles of the five parts after cooling. In addition, the upper and lower bearing seats and the motor shell are made of steel, and only the sensor and the bearing seat are made of aluminum alloy, which will inevitably have a certain amount of change (the actual measurement result is more than 0.005mm, and the basic distribution is between 0.005-0.01mm).

[0006] The difference between the outer diameter of the rotor and the inner diameter of the radial stator is only 0.1mm, and the above two aspects will cause the proportion of part of the data drift to exceed 10%, which will have a great influence on the stability of the rotor during high-speed rotation, causing the vibration of the molecular pump rotor to exceed the tolerance, and in severe cases, even causing the rotor turbine to crack and other serious accident risks.

[0007] The research and development team believes that it is necessary to detect the concentricity of the radial sensor of the magnetic suspension molecular pump. However, there is no related research on the detection of the concentricity of the radial sensor of the magnetic suspension molecular pump in the prior art. SUMMARY

[0008] The purpose of the present application is to provide a magnetic suspension molecular pump radial sensor concentricity detection tool to solve the above problems of the prior art.

[0009] Another purpose of the present application is to provide a magnetic suspension molecular pump radial sensor concentricity detection method.

[0010] Still another purpose of the present application is a magnetic suspension molecular pump radial sensor concentricity qualification detection method.

[0011] The technical solution of the present application is as follows:

[0012] A magnetic suspension molecular pump radial sensor concentricity detection tool tests the concentricity of the upper radial sensor and the lower radial sensor of the radial stator assembly to be tested.

[0013] It comprises:

[0014] a, a tool shaft arranged in a vertical state, arranged at the lower part of the moving end of the tool shaft motion control assembly;

[0015] b, a tool shaft motion control assembly for controlling the position of the tool shaft; the tool shaft motion control assembly can control the tool shaft to move in the vertical direction;

[0016] c, a high-precision rotary platform assembly as a placement platform for the radial stator assembly to be tested; the high-precision rotary platform assembly comprises a V-shaped positioning block, a clamping device, and a precision rotary main shaft driven turntable;

[0017] The V-shaped positioning block and the clamping device are used to fix the radial stator assembly to be tested on the precision rotary main shaft driven turntable;

[0018] The precision rotary main shaft driven turntable is used to drive the radial stator assembly to be tested to rotate;

[0019] d, the tool shaft motion control assembly can control the tool shaft to enter the radial stator assembly to be tested.

[0020] Further, the high-precision rotary platform assembly further comprises an angle sensor; the angle sensor is used to measure the rotation angle of the precision rotary main shaft driven turntable.

[0021] Further, the rotation axis of the precision rotary main shaft driven turntable is coaxial with the rotation axis of the bearing seat of the radial stator assembly to be tested.

[0022] Further, the tool shaft motion control assembly can also control the tool shaft to move in the horizontal direction.

[0023] Further, the difference between the diameter of the inner cylindrical surface of the upper radial sensor of the radial stator assembly and the outer surface diameter of the tool shaft is 2mm.

[0024] Further, the tool shaft motion control assembly can control the tool shaft to extend into the lower part of the lower radial sensor of the radial stator assembly to be tested, so that the upper radial sensor and the lower radial sensor of the radial stator assembly to be tested can measure data.

[0025] A magnetic suspension molecular pump radial sensor concentricity detection method tests the concentricity of the upper radial sensor and the lower radial sensor of the radial stator assembly to be tested.

[0026] The upper radial sensor has four measuring points, and the phase angles of the four measuring points are 90°, which are denoted as the first to fourth measuring points. The lower radial sensor has four measuring points, and the phase angles of the four measuring points are 90°, which are denoted as the fifth to eighth measuring points. The first measuring point is an X+ measuring point, the second measuring point is a Y+ measuring point, the third measuring point is an X- measuring point, and the fourth measuring point is a Y- measuring point. The fifth measuring point is an X+ measuring point, the sixth measuring point is a Y+ measuring point, the seventh measuring point is an X- measuring point, and the eighth measuring point is a Y- measuring point.

[0027] It includes the following steps:

[0028] S100, mounting the radial stator assembly to be tested on a precision rotary main shaft driven turntable: fixing the radial stator assembly to be tested on the precision rotary main shaft driven turntable through a V-shaped positioning block and a clamping device.

[0029] S200, moving the tool shaft by a tool shaft motion control assembly so that the tool shaft is inserted into the radial stator assembly to be tested.

[0030] S300, testing δ 短1 ; 短8 , δ 长1 ; 短8 ;

[0031] For any δ 短i , δ 长i , the testing method is as follows:

[0032] The precision rotary main shaft driven turntable rotates with the radial stator assembly to be tested for one revolution, and in this process, the minimum distance value measured by the ith measuring point is δ 短i , and the maximum distance value is δ 长i .

[0033] S400, solving the eccentricity L between the center points of the upper radial sensor and the lower radial sensor.

[0034] L = 0.5 × [ ( δ 短5 + δ 长5 - δ 短7 - δ 长7 - δ 短1 - δ 长1+ δ 短3 + δ 长3 ) 2 + ( δ 短6 + δ 长6 - δ 短8 - δ 长8 - δ 短2 - δ 长2 + δ 短4 + δ 长4 ) 2 ] 0.5 .

[0035] A magnetic suspension molecular pump radial sensor concentricity detection method tests the concentricity of an upper radial sensor and a lower radial sensor of a radial stator assembly to be measured;

[0036] The upper radial sensor has four measuring points, and the phase angles of the four measuring points are 90°, and are denoted as first to fourth measuring points; the lower radial sensor has four measuring points, and the phase angles of the four measuring points are 90°, and are denoted as fifth to eighth measuring points; the first measuring point is an X+ measuring point, the second measuring point is a Y+ measuring point, the third measuring point 1-3 is an X- measuring point, and the fourth measuring point is a Y- measuring point; the fifth measuring point is an X+ measuring point, the sixth measuring point is a Y+ measuring point, the seventh measuring point is an X- measuring point, and the eighth measuring point is a Y- measuring point;

[0037] It comprises the following steps:

[0038] S100, mounting the radial stator assembly to be measured on a precision rotary main shaft driving turntable: fixing the radial stator assembly to be measured on the precision rotary main shaft driving turntable through a V-shaped positioning block and a clamping device;

[0039] S200, moving a tool shaft of a tool shaft motion control assembly so that the tool shaft is inserted into the radial stator assembly to be measured;

[0040] S300, solving the eccentricity L between the center points of the upper radial sensor and the lower radial sensor;

[0041] L takes the average value of any one or any two of L1, L2, L3 and L4, or the average value of any three or the average value of four;

[0042] L1 is an eccentricity solved by the fourth and second measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor;

[0043] L2 is an eccentricity solved by the fourth and second measuring points of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor;

[0044] L3 is an eccentricity solved by the third and first measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor;

[0045] L4 is the eccentricity solved by the third measuring point of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor;

[0046] Lp,q,m,n is the eccentricity solved by the pth and qth measuring points of the upper radial sensor and the mth and nth measuring points of the lower radial sensor s The method comprises the following sub-steps:

[0047] S401, test δ 短 p, δ 短q , δ 短 m, δ 短 n, δ 长 p, δ 长q , δ 长 m, δ 长 n, D 测p , D 测q , D 测m , D 测n ;

[0048] For any δ 短i , δ 长i , D 测i , i is any value of p, q, m, n, and the acquisition method is as follows:

[0049] The precision rotary spindle driving turntable rotates with the radial stator assembly to be measured for one circle, and the minimum value of the distance measured by the ith measuring point is δ 短i , and the maximum value of the distance is δ 长i ;

[0050] D 测i = δ 短i + δ 长i + D0, D 测i represents the rotating diameter of the ith measuring point, and D0 represents the diameter of the tool shaft;

[0051] S402, test β pq , β mq , β nq :

[0052] For any β vq , it refers to the included angle of the counterclockwise rotation of AQ to AV, wherein v is any value of p, m, n; A, Q, V respectively represent the projection points of the rotating shaft of the precision rotary spindle driving turntable, the qth measuring point and the vth measuring point in the same horizontal plane; and the test method is as follows:

[0053] Step a, rotate the precision rotary main shaft driving turntable so that the first v measuring point measures the minimum distance value as the starting point, and the precision rotary main shaft driving turntable rotates clockwise until the q measuring point measures the minimum distance value as the end point. The angle between the starting point and the end point is recorded as β vq-顺 ;

[0054] Step b, rotate the precision rotary main shaft driving turntable so that the first v measuring point measures the minimum distance value as the starting point, and the precision rotary main shaft driving turntable rotates counterclockwise until the q measuring point measures the minimum distance value as the end point. The angle between the starting point and the end point is recorded as β vq-逆 ;

[0055] β vq =β vq-逆 -(β vq-顺+ β vq-逆 -360°) / 2;

[0056] S403, solve L s :

[0057] L s =0.5×((D 测m ·cosβ mq + D 测n ·cosβ nq -D 测q -D 测p ·cosβ pq ) 2 +(D 测m ·sinβ mq +D 测n ·sinβ nq -D 测p ·sinβ pq ) 2 ) 0.5 .

[0058] Further, S200 also includes: the precision rotary main shaft driving turntable rotates with the radial stator assembly to be measured, and the running-in of the rotating mechanism is performed.

[0059] A magnetic suspension molecular pump radial sensor concentricity qualification detection method, the concentricity of the upper radial sensor and the lower radial sensor of the radial stator assembly to be measured is tested at least twice;

[0060] Each time, the position of the tool shaft is different, that is, the motion control assembly moves the tool shaft to different positions, and then the aforementioned magnetic suspension molecular pump radial sensor concentricity detection method is used to test the concentricity of the upper radial sensor and the lower radial sensor of the radial stator assembly to be measured.

[0061] If each detected eccentricity L is less than the eccentricity threshold [L], it indicates that the magnetic suspension molecular pump radial sensor concentricity is qualified, otherwise, it is unqualified.

[0062] The beneficial effects of the present application are:

[0063] Firstly, the present application develops a magnetic suspension molecular pump radial sensor concentricity detection tool. In hardware design, the core is that: the tool shaft motion control assembly can control the tool shaft to move in the vertical direction, that is, it can control the tool shaft to be inserted into the radial stator assembly to be measured (the tool shaft has only one vertical degree of freedom) ; the high-precision rotary platform assembly is used as a placement platform for the radial stator assembly to be measured; the high-precision rotary platform assembly comprises a V-shaped positioning block, a clamping device and a precision rotary main shaft driven turntable; the V-shaped positioning block and the clamping device are used to fix the radial stator assembly to be measured on the precision rotary main shaft driven turntable; the precision rotary main shaft driven turntable is used to drive the radial stator assembly to be measured to rotate. Through the cooperative operation of the above design, the concentricity detection of the magnetic suspension molecular pump radial sensor can be realized.

[0064] In addition, in the hardware design, the rotation axis of the precision rotary main shaft driven turntable is coaxial with the rotation axis of the bearing seat of the radial stator assembly to be measured (the accurate expression is that the distance between the rotation axis of the precision rotary main shaft driven turntable and the rotation axis of the bearing seat of the radial stator assembly to be measured is less than half of the difference between the diameter of the upper radial sensor inner cylindrical surface of the radial stator assembly and the outer surface diameter of the tool shaft), so as to avoid the collision between the precision rotary main shaft driven turntable and the tool shaft during the rotary motion of the precision rotary main shaft driven turntable.

[0065] Secondly, the magnetic suspension molecular pump radial sensor concentricity detection method is another research difficulty of the present application. The present application proposes the following two methods for concentricity detection.

[0066] The first method is: S100, installing the radial stator assembly to be measured on the precision rotary main shaft driven turntable: the V-shaped positioning block and the clamping device are used to fix the radial stator assembly to be measured on the precision rotary main shaft driven turntable;

[0067] S200, the tool shaft motion control assembly moves the tool shaft so that the tool shaft is inserted into the radial stator assembly to be measured;

[0068] S300, solving the eccentricity L between the center points of the upper radial sensor and the lower radial sensor;

[0069] L takes the average value of any one or any two of L1, L2, L3 and L4, or the average value of any three or four of them;

[0070] L1 is the eccentricity solved by the fourth and second measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor;

[0071] L2 is the eccentricity solved by the fourth and second measuring points of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor;

[0072] L3 is the eccentricity solved by the third and first measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor;

[0073] L4 is the eccentricity solved by the third and first measuring points of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor;

[0074] Wherein, the eccentricity Lp,qm,n solved by the pth and qth measuring points of the upper radial sensor and the mth and nth measuring points of the lower radial sensor s The method comprises the following sub-steps:

[0075] S401, test δ 短 p, δ 短q , δ 短 m, δ 短 n, δ 长 p, δ 长q , δ 长 m, δ 长 n, D 测p , D 测q , D 测m , D 测n ;

[0076] For any δ 短i , δ 长i , D 测i , i is any value of p, q, m, n, and the method for obtaining i is as follows:

[0077] The precision rotary main shaft driving turntable rotates with the radial stator assembly to be measured for one revolution, and the minimum value of the distance measured by the ith measuring point in this process is δ 短i , and the maximum value of the distance is δ 长i ;

[0078] D 测i = δ 短i + δ 长i + D0, D 测i indicates the rotating diameter of the ith measuring point, and D0 indicates the diameter of the tool shaft;

[0079] S402, test β pq , β mq , β nq :

[0080] For any β vq, which refers to the included angle of AQ counterclockwise rotation to AV, wherein v is any numerical value of p, m, n; A, Q, V respectively represent the rotation axis of the precision rotary main shaft driving turntable, the qth measuring point, and the projection point of the vth measuring point in the same horizontal plane; the test method is as follows:

[0081] Step a, rotate the precision rotary main shaft driving turntable so that the vth measuring point measures the minimum distance value as the starting point, and the precision rotary main shaft driving turntable rotates clockwise until the qth measuring point measures the minimum distance value as the end point; the angle through which the precision rotary main shaft driving turntable rotates between the starting point and the end point is recorded as β vq-顺 ;

[0082] Step b, rotate the precision rotary main shaft driving turntable so that the vth measuring point measures the minimum distance value as the starting point, and the precision rotary main shaft driving turntable rotates counterclockwise until the qth measuring point measures the minimum distance value as the end point; the angle through which the precision rotary main shaft driving turntable rotates between the starting point and the end point is recorded as β vq-逆 ;

[0083] β vq =β vq-逆 -(β vq-顺+ β vq-逆 -360°) / 2;

[0084] S403, solve L s :

[0085] L s =0.5×((D 测m ·cosβ mq + D 测n ·cosβ nq -D 测q -D 测p ·cosβ pq ) 2 +(D 测m ·sinβ mq +D 测n ·sinβ nq -D 测p ·sinβ pq ) 2 ) 0.5 .

[0086] The second method: S100, install the radial stator assembly to be measured on the precision rotary main shaft driving turntable: fix the radial stator assembly to be measured on the precision rotary main shaft driving turntable through the V-shaped positioning block and the clamping device;

[0087] S200, move the tool shaft of the tool shaft motion control assembly so that the tool shaft is inserted into the radial stator assembly to be measured;

[0088] S300, test delta 短1 ~delta 短8 , delta 长1 ~delta 短8 ;

[0089] For any delta 短i , delta 长i , the test method is as follows:

[0090] The precision rotary spindle drive turntable rotates with the radial stator assembly to be tested for one revolution, and in this process, the minimum value of the distance measured by the ith measuring point is delta 短i , delta 长i ;

[0091] S400, solve the eccentricity L between the center points of the upper radial sensor and the lower radial sensor;

[0092] L = 0.5 x [(delta 短5 + delta 长5 - delta 短7 - delta 长7 - delta 短1 - delta 长1 + delta 短3 + delta 长3 ) 2 + (delta 短6 + delta 长6 - delta 短8 - delta 长8 - delta 短2 - delta 长2 + delta 短4 + delta 长4 ) 2 ] 0.5 .

[0093] Thirdly, the application provides a magnetic suspension molecular pump radial sensor concentricity qualification detection method, which tests the concentricity of the upper radial sensor and the lower radial sensor of the radial stator assembly to be tested at least twice.

[0094] In each detection, the position of the tooling shaft is different, that is, the motion control assembly moves the tooling shaft to different positions (this is the purpose of the tooling shaft being able to move along the horizontal direction), and the magnetic suspension molecular pump radial sensor concentricity detection method is used to test the concentricity of the upper radial sensor and the lower radial sensor of the radial stator assembly to be tested.

[0095] If the eccentricity L detected each time is less than the eccentricity threshold [L] (for example, 0.01216 mm), it indicates that the magnetic suspension molecular pump radial sensor concentricity is qualified, otherwise, it is not qualified. BRIEF DESCRIPTION OF DRAWINGS

[0096] The application will be further described in detail below with reference to the embodiments in the drawings, but does not constitute any limitation to the application.

[0097] Figure 1 is a schematic view of the radial stator assembly.

[0098] Figure 2 is a three-dimensional structure diagram of a magnetic suspension molecular pump radial sensor concentricity detection tool of the application.

[0099] Figure 3 is a three-dimensional structure design schematic diagram of a high-precision rotary platform assembly.

[0100] Figure 4 is a schematic diagram of the physical meaning of O, A, and B.

[0101] Figure 5 is a physical meaning diagram of δ 短i , δ 长i , and D 测i .

[0102] Figure 6 is a physical meaning diagram of β 42 .

[0103] Figure 7 is a coordinate system schematic diagram when the fourth and second measuring points of the upper radial sensor are used to solve the coordinates of point O, and the eighth and sixth measuring points of the lower radial sensor are used to solve the coordinates of point O'.

[0104] The drawings are described as follows:

[0105] The upper magnetic bearing 1, the upper radial sensor 2, the lower radial sensor 3, the lower magnetic bearing 4, the first measuring point 1-1, the second measuring point 1-2, the third measuring point 1-3, and the fourth measuring point 1-4.

[0106] The magnetic suspension molecular pump radial sensor concentricity detection tool 1000, and the radial stator assembly 2000 to be measured.

[0107] The tool shaft 100, the tool shaft motion control assembly 200, the high-precision rotary platform assembly 300, the V-shaped positioning block 301, the clamping device 302, and the precision rotary main shaft driving turntable 303. DETAILED DESCRIPTION

[0108] In order to make the purpose, technical scheme and advantages of the application more clear, the technical scheme of the application will be described clearly and completely below with reference to the specific embodiments of the application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0109] <Embodiment One>

[0110] Figure 2 A three-dimensional structure diagram of a magnetic suspension molecular pump radial sensor concentricity detection tool 1000 is shown. A magnetic suspension molecular pump radial sensor concentricity detection tool tests the concentricity of the upper radial sensor and the lower radial sensor of the radial stator assembly 2000 to be measured;

[0111] It comprises:

[0112] a, the tool shaft 100 is arranged in a vertical state, which is arranged at the lower part of the moving end of the tool shaft motion control assembly 200.

[0113] b, the tool shaft motion control assembly 200 is used to control the position of the tool shaft 100.

[0114] c, the high-precision rotary platform assembly 300 is used as a placement platform for the radial stator assembly to be measured.

[0115] Figure 3 A three-dimensional structure diagram of the high-precision rotary platform assembly 300 is shown. The high-precision rotary platform assembly 300 comprises a V-shaped positioning block 301, a clamping device 302, and a precision rotary main shaft driven turntable 303. The radial stator assembly to be measured is fixed on the precision rotary main shaft driven turntable 303 through the V-shaped positioning block 301 and the clamping device 302. After clamping and fixing, the rotation axis of the precision rotary main shaft driven turntable is coaxial with the rotation axis of the bearing seat of the radial stator assembly to be measured, and the precision rotary main shaft driven turntable 303 rotates with the radial stator assembly 2000.

[0116] d, the relationship among the tool shaft 100, the tool shaft motion control assembly 200, and the precision rotary main shaft driven turntable 303 is that the tool shaft 100 can be inserted into the radial stator assembly 2000 to be measured under the operation of the tool shaft motion control assembly 200.

[0117] It should be noted that the high-precision rotary platform assembly 300 further comprises an angle sensor, which is used to measure the rotation angle of the precision rotary main shaft driven turntable 303.

[0118] It should be noted that the tool shaft motion control assembly 200 has one or two or three degrees of freedom. That is, it is necessary for the tool shaft 100 to be able to move vertically. In addition, as Figure 1As shown, the tooling axis motion control assembly 200 can control the tooling axis 100 to move in the vertical direction and the horizontal direction (i.e., the X direction) (i.e., the tooling axis motion control assembly 200 can control the tooling axis 100 to move in two directions). In addition, the tooling axis motion control assembly 200 uses a robotic arm, which makes it possible for the tooling axis 100 to move in the vertical direction and two horizontal directions.

[0119] It should be noted that after the radial stator assembly 2000 under test is installed, the distance between the spindle of its bearing housing and the rotating spindle of the precision rotary spindle drive turntable 303 is less than 2mm. Preferably, after the radial stator assembly 2000 under test is installed, the spindle of its bearing housing coincides with the rotating spindle of the precision rotary spindle drive turntable 303. This is to ensure that when the radial stator assembly 2000 under test rotates under the drive of the precision rotary spindle drive turntable 303, it avoids collision with the tooling shaft 100.

[0120] It should be noted that during testing, the tooling shaft 100 extends into the lower radial sensor of the radial stator assembly 2000 under test, ensuring that both the upper and lower radial sensors of the radial stator assembly 2000 under test can measure data.

[0121] It should be noted that the difference between the diameter of the inner cylindrical surface of the upper radial sensor of the radial stator assembly and the outer surface diameter of the tooling shaft 100 is 2mm.

[0122] A method for detecting the concentricity of a radial sensor for a magnetically levitated molecular pump includes the following steps:

[0123] S100, the radial stator assembly 2000 to be tested is installed on the test station, that is, the radial stator assembly 2000 to be tested is installed on the precision rotary spindle drive turntable 303: the radial stator assembly to be tested is fixed on the precision rotary spindle drive turntable 303 by the V-shaped positioning block 301 and the clamping device 302.

[0124] S200, the tooling axis motion control assembly 200 moves the tooling axis 100 so that the tooling axis 100 is inserted into the radial stator assembly 2000 to be tested;

[0125] S300, the precision rotary spindle drives the turntable 303 to rotate the radial stator assembly 2000 under test, and performs the running-in of the rotating mechanism (about 1 minute).

[0126] S400, calculate the eccentricity L between the upper radial sensor and the lower radial sensor;

[0127] The upper radial sensor has four measuring points, with a phase angle of 90° between the four measuring points, and these are referred to as the first to the fourth measuring points; the lower radial sensor has four measuring points, with a phase angle of 90° between the four measuring points, and these are referred to as the fifth to the eighth measuring points.

[0128] The first measuring point 1-1 is an X+ measuring point, the second measuring point 1-2 is a Y+ measuring point, the third measuring point 1-3 is an X- measuring point, and the fourth measuring point 1-4 is a Y- measuring point;

[0129] The fifth measuring point is an X+ measuring point, the sixth measuring point is a Y+ measuring point, the seventh measuring point is an X- measuring point, and the eighth measuring point is a Y- measuring point;

[0130] For any of the first to eighth measuring points, it is a calibrated eddy current sensor capable of measuring the distance from the tooling shaft;

[0131] L is L1 or L2 or L3 or L4 or the average of L1, L2 or the average of L1, L3 or the average of L1, L4 or the average of L2, L3 or the average of L2, L4 or the average of L3, L4 or the average of L1, L2, L3 or the average of L1, L2, L4 or the average of L1, L3, L4 or the average of L2, L3, L4 or the average of L1, L2, L3, L4;

[0132] L1 is the eccentricity solved by the fourth and second measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor;

[0133] L2 is the eccentricity solved by the fourth and second measuring points of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor;

[0134] L3 is the eccentricity solved by the third and first measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor;

[0135] L4 is the eccentricity solved by the third and first measuring points of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor.

[0136] The eccentricity L solved by the pth and qth measuring points of the upper radial sensor and the mth and nth measuring points of the lower radial sensor s The method comprises the following sub-steps:

[0137] S401, test δ 短 p, δ 短q , δ 短 m, δ 短 n, δ 长 p, δ 长q , δ 长 m, δ 长 n, D 测p , D 测q , D 测m , D 测n ;

[0138] As Figure 4As shown, points A, B, and O are the projection points of the rotation axis of the precision rotary spindle drive turntable, the central axis of the tooling axis, and the midpoint of the upper radial sensor on the same horizontal plane, respectively.

[0139] Figure 5 It shows δ 短i δ 长i D 测i The physical meaning of δ. 短i δ 长i D 测i , where i is any value of p, q, m, n, and is obtained as follows:

[0140] The precision rotary spindle drives the turntable to rotate the radial stator assembly under test one revolution. During this process, the minimum distance measured at the i-th measuring point is δ. 短i The maximum distance is δ 长i ;

[0141] D 测i =δ 短i +δ 长i +D0,D 测i Di represents the rotation diameter of the i-th measuring point, and D0 represents the diameter of the tooling shaft;

[0142] S402, Test β pq β mq β nq :

[0143] For any β vq , refers to the angle between AQ and AV when AQ rotates counterclockwise, where v is any value of p, m, and n; A, Q, and V represent the rotation axis of the precision rotary spindle drive turntable, the projection points of the q-th and v-th measuring points on the same horizontal plane, respectively; the test method is as follows:

[0144] Test β pq β mq β nq :

[0145] For any β vq , refers to the angle between AQ and AV when AQ rotates counterclockwise, where v is any value of p, m, and n; A, Q, and V represent the rotation axis of the precision rotary spindle drive turntable, the projection points of the q-th and v-th measuring points on the same horizontal plane, respectively; the test method is as follows:

[0146] Step a: Rotate the precision rotary spindle drive turntable until the minimum distance value measured at the v-th measuring point is obtained, taking this as the starting point. Rotate the precision rotary spindle drive turntable clockwise until the minimum distance value measured at the q-th measuring point is obtained, taking this as the ending point. The angle rotated by the precision rotary spindle drive turntable from the starting point to the ending point is denoted as β. vq-顺 ;

[0147] Step b: Rotate the precision rotary spindle drive turntable until the minimum distance measured at the v-th measuring point is obtained, taking this as the starting point. Rotate the precision rotary spindle drive turntable counterclockwise until the minimum distance measured at the q-th measuring point is obtained, taking this as the ending point. The angle rotated by the precision rotary spindle drive turntable from the starting point to the ending point is denoted as β. vq-逆 ;

[0148] β vq =β vq-逆 -(β) vq-顺+ β vq-逆 -360°) / 2;

[0149] S403, Solve for L s :

[0150] With point A as the origin, the direction AQ points to is the positive X-axis, and AQ rotated 90° counterclockwise is the positive Y-axis; O and O' represent the coordinates of the projection points of the upper and lower radial sensors on the horizontal plane in the above-mentioned planar coordinate system.

[0151] The coordinates of the projection of the q-th measuring point onto the horizontal plane are (D 测q ,0);

[0152] The coordinates of the projection of the p-th measuring point onto the horizontal plane are (D 测p ·cosβ pq D 测p ·sinβ pq );

[0153] The coordinates of the projection of the m-th measuring point onto the horizontal plane are (D 测m ·cosβ mq D 测m ·sinβ mq );

[0154] The coordinates of the projection of the nth measuring point onto the horizontal plane are (D 测n ·cosβ nq D 测n ·sinβ nq );

[0155] Then we have:

[0156] X O =(D 测q + D 测p ·cosβ pq ) / 2;

[0157] Y O= D 测p ·sinβ pq / 2;

[0158] Xo'=(D 测m ·cosβ mq + D 测n ·cosβ nq ) / 2;

[0159] Yo' = (D) 测m ·sinβ mq + D 测n ·sinβ nq ) / 2;

[0160] Therefore, the eccentricity L between the upper radial sensor and the lower radial sensor can be determined as follows:

[0161] L = ((Xo' - Xo)) 2 +(Yo'- Yo) 2 ) 0.5 .

[0162] Taking the calculation of eccentricity using the fourth and second measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor as an example.

[0163] First, measure β 42 β 82 β 62 The projections of the i-th and j-th measuring points onto the horizontal plane are points i and j, respectively, and β ij This refers to the angle between Aj and Ai when Aj rotates counterclockwise.

[0164] any β ij The testing method is:

[0165] Step a: When the distance measured at the i-th measuring point is at its minimum value, the precision rotary spindle drives the turntable 303 to rotate clockwise until the distance measured at the j-th measuring point is at its minimum value. The angle through which the precision rotary spindle drives the turntable 303 rotates is denoted as β. ij-顺 ;

[0166] Step b: When the minimum distance is measured at the i-th measuring point, the precision rotary spindle drives the turntable 303 to rotate counterclockwise until the minimum distance is measured at the j-th measuring point. The angle through which the precision rotary spindle drives the turntable 303 rotates is denoted as β. ij-逆 ;

[0167] β ij =β ij-逆 -(β) ij-顺+ β ij-逆 -360°) / 2.

[0168] By rotating clockwise and counterclockwise, measurement errors are reduced.

[0169] The above method can measure β42 β 82 β 62 .

[0170] Then, the coordinates of point O are solved using the fourth and second measuring points of the upper radial sensor, and the coordinates of point O' are solved using the eighth and sixth measuring points of the lower radial sensor.

[0171] The method for calculating the coordinates of point O using the datasets from the fourth and second measurement points is as follows:

[0172] like Figure 7 As shown, with point A as the origin of the coordinate system, the direction in which point A points to the projection of the second measuring point on the horizontal plane is the positive X-direction, and the positive Y-direction is the direction rotated 90° counterclockwise from the aforementioned positive X-direction.

[0173] The coordinates of the projection of the second measuring point onto the horizontal plane are (D) 测2 ,0);

[0174] The coordinates of the projection of the fourth measuring point onto the horizontal plane are (D) 测4 ·cosβ 42 D 测4 ·sinβ 42 );

[0175] have:

[0176] X O =(D 测2 + D 测4 ·cosβ 42 ) / 2;

[0177] Y O= D 测4 ·sinβ 42 / 2;

[0178] The coordinates of the projection of the eighth measuring point onto the horizontal plane are (D) 测8 ·cosβ 82 D 测8 ·sinβ 82 );

[0179] The coordinates of the projection of the sixth measuring point onto the horizontal plane are (D) 测6 ·cosβ 62 D 测6 ·sinβ 62 );

[0180] have:

[0181] Xo'=(D 测8 ·cosβ 82 + D 测6 ·cosβ 62 ) / 2;

[0182] Yo' = (D) 测8 ·sinβ 82 + D 测6 ·sinβ 62 ) / 2;

[0183] Therefore, the eccentricity L between the upper radial sensor and the lower radial sensor can be determined as follows:

[0184] L = ((Xo' - Xo)) 2 +(Yo'- Yo) 2 ) 0.5 .

[0185] It should be noted that, for L, the second simplified algorithm can also be used:

[0186] With point A as the origin of the coordinate system, the detection direction of the third measuring point 1-3 pointing to the first measuring point 1-1 is the positive X direction, and the detection direction of the fourth measuring point 1-4 pointing to the second measuring point 1-2 is the positive Y direction.

[0187] The coordinates of point O can be approximately solved using the following formula:

[0188] Xo≈D 测1 / 2-D 测3 / 2=(δ 短1 +δ 长1 -δ 短3 -δ 长3 ) / 2,Yo≈D 测2 / 2-D 测4 / 2=(δ 短2 +δ 长2 -δ 短4 -δ 长4 ) / 2.

[0189] Correspondingly, point O' is the projection of the midpoint of the lower radial sensor onto the horizontal plane. Therefore:

[0190] With point A as the origin, the coordinates of point O' can be approximately solved using the following formula:

[0191] Xo'≈D 测5 / 2-D 测7 / 2=(δ 短5 +δ 长5 -δ 短7 -δ 长7 ) / 2,Yo'≈D 测6 / 2-D 测8 / 2=(δ 短6 +δ 长6 -δ 短8 -δ 长8 ) / 2.

[0192] Therefore, the eccentricity L between the upper radial sensor and the lower radial sensor can be determined as follows:

[0193] L = ((Xo' - Xo)) 2 +(Yo'- Yo) 2 ) 0.5 .

[0194] In other words, when detecting the concentricity of a radial sensor for a magnetic levitation molecular pump, the tooling shaft remains stationary. The test can be completed simply by rotating the precision rotary spindle to drive the turntable to rotate synchronously and cause the radial stator assembly under test to rotate.

[0195] In actual testing, the concentricity detection of a radial sensor of a magnetic levitation molecular pump is performed multiple times. That is, when the tooling shaft motion control component 200 moves the tooling shaft to different positions, the concentricity of the radial sensor of the magnetic levitation molecular pump is detected separately.

[0196] If the detected eccentricity L is less than the eccentricity [L] threshold each time, it indicates that the concentricity of the radial sensor of the magnetic levitation molecular pump meets the requirements; otherwise, it does not meet the requirements.

[0197] The meanings of the physical symbols used in this application are explained below:

[0198] A, B, O, and O' represent the projection points of the rotation axis of the precision rotary spindle drive turntable, the central axis of the tooling axis, the midpoint of the upper radial sensor, and the midpoint of the lower radial sensor onto the same horizontal plane, respectively.

[0199] L1 represents the eccentricity calculated using the fourth and second measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor.

[0200] L2 represents the eccentricity calculated using the fourth and second measuring points of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor.

[0201] L3 represents the eccentricity calculated using the third and first measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor.

[0202] L4 represents the eccentricity calculated using the third and first measuring points of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor.

[0203] L is the eccentricity between the upper radial sensor and the lower radial sensor.

[0204] (Xo, Yo) and (Xo', Yo') represent the coordinates of O and O' in the same coordinate system, respectively.

[0205] p, q, m, n are the parameters of the measuring point, such as: p=4, q=2 or p=2, q=4 or p=3, q=1 or p=1, q=3, m=8, n=6 or m=6, n=8 or m=7, n=5 or m=5, n=7.

[0206] L s L1, L2, L3, or L4 represents the eccentricity calculated by measuring the p and q points of the upper radial sensor and the m and n points of the lower radial sensor.

[0207] δ 短 p、δ 短q δ 短 m、δ 短 n、δ 短i These represent the minimum distance values ​​measured at measuring points p, q, m, n, and i when the precision rotary spindle drives the turntable to rotate one revolution with the radial stator assembly under test.

[0208] δ 长 p、δ 长q δ 长 m、δ 长 n、δ 长i These represent the maximum distance values ​​measured at measuring points p, q, m, n, and i respectively, when the precision rotary spindle drives the turntable to rotate the radial stator assembly under test for one revolution.

[0209] D 测p D 测q D 测m D 测n D 测i These represent the rotation diameters of the p-th, q-th, m-th, n-th, and i-th measuring points when the precision rotary spindle drives the turntable to rotate with the radial stator assembly under test.

[0210] D0 represents the diameter of the tooling shaft.

[0211] B vq : The counterclockwise rotation angle from the q-th measuring point to the v-th measuring point, specifically, refers to the angle between AQ and AV when rotated counterclockwise; A, Q, and V represent the rotation axis of the precision rotary spindle drive turntable, the projection points of the q-th measuring point, and the v-th measuring point on the same horizontal plane, respectively.

[0212] β vq-顺 Let β be the starting point, where the distance measured at the v-th measuring point is minimized by rotating the precision rotary spindle drive turntable. The turntable then rotates clockwise until the distance measured at the q-th measuring point is minimized, which is the ending point. The angle β traversed by the precision rotary spindle drive turntable from the starting point to the ending point is denoted as β. vq-顺 .

[0213] β vq-逆Let β be the starting point, where the distance measured at the v-th measuring point is minimized by rotating the precision rotary spindle drive turntable. The turntable then rotates counter-clockwise until the distance measured at the q-th measuring point is minimized, which is the ending point. The angle β traversed by the precision rotary spindle drive turntable from the starting point to the ending point is denoted as β. vq-逆 .

[0214] The above-described embodiments are preferred embodiments of this application and are only used to facilitate the illustration of this application. They are not intended to limit this application in any way. Any person with ordinary knowledge in the art can make equivalent embodiments by making partial modifications or alterations to the technical content disclosed in this application without departing from the scope of the technical features of this application. Such equivalent embodiments are still within the scope of the technical features of this application.

Claims

1. A magnetic suspension molecular pump radial sensor concentricity detection method, which adopts a magnetic suspension molecular pump radial sensor concentricity detection tool to test the concentricity of an upper radial sensor and a lower radial sensor of a radial stator assembly to be tested. The magnetic suspension molecular pump radial sensor concentricity detection tool comprises: a, a tool shaft arranged in a vertical state, which is arranged at the lower part of the moving end of a tool shaft movement control assembly; b, a tool shaft movement control assembly for controlling the position of the tool shaft; the tool shaft movement control assembly can control the tool shaft to move in the vertical direction; c, a high-precision rotary platform assembly as a placement platform for the radial stator assembly to be tested; The high-precision rotary platform assembly comprises a V-shaped positioning block, a clamping device, and a precision rotary main shaft driving turntable; the V-shaped positioning block and the clamping device are used to fix the radial stator assembly to be tested on the precision rotary main shaft driving turntable; the precision rotary main shaft driving turntable is used to drive the radial stator assembly to be tested to rotate; d, the tool shaft movement control assembly can control the tool shaft to enter the radial stator assembly to be tested; The upper radial sensor has four measuring points, and the phase angles of the four measuring points are 90°, which are recorded as the first to fourth measuring points; the lower radial sensor has four measuring points, and the phase angles of the four measuring points are 90°, which are recorded as the fifth to eighth measuring points; the first measuring point is an X+ measuring point, the second measuring point is a Y+ measuring point, the third measuring point is an X- measuring point, and the fourth measuring point is a Y- measuring point; the fifth measuring point is an X+ measuring point, the sixth measuring point is a Y+ measuring point, the seventh measuring point is an X- measuring point, and the eighth measuring point is a Y- measuring point; It is characterized by the following steps: S100, installing the radial stator assembly to be tested on the precision rotary main shaft driving turntable: fixing the radial stator assembly to be tested on the precision rotary main shaft driving turntable through the V-shaped positioning block and the clamping device; S200, moving the tool shaft by the tool shaft movement control assembly, so that the tool shaft is inserted into the radial stator assembly to be tested; S300, test delta 短1 delta 短8 delta 长1 delta 短8 ; For any δ 短i , δ 长i , the test method is as follows: The precision rotary main shaft drives the rotary table to rotate one circle with the radial stator assembly to be measured, and in the process, the minimum value of the distance measured by the ith measuring point is δ 短i , and the maximum value of the distance is δ 长i . S400, solving the eccentricity L between the center points of the upper radial sensor and the lower radial sensor; L = 0.5 x [(δ 短5 + δ 长5 - δ 短7 - δ 长7 - δ 短1 - δ 长1 + δ 短3 + δ 长3 ) 2 + (δ 短6 + δ 长6 - δ 短8 - δ 长8 - δ 短2 - δ 长2 + δ 短4 + δ 长4 ) 2 ] 0.5 . 2.A magnetic suspension molecular pump radial sensor concentricity detection method, which adopts a magnetic suspension molecular pump radial sensor concentricity detection tool to test the concentricity of an upper radial sensor and a lower radial sensor of a radial stator assembly to be tested. The magnetic suspension molecular pump radial sensor concentricity detection tool comprises: a, a tool shaft arranged in a vertical state, which is arranged at the lower part of the moving end of a tool shaft movement control assembly; b, a tool shaft movement control assembly for controlling the position of the tool shaft; the tool shaft movement control assembly can control the tool shaft to move in the vertical direction; c, a high-precision rotary platform assembly as a placement platform for the radial stator assembly to be tested; The high-precision rotary platform assembly comprises a V-shaped positioning block, a clamping device, and a precision rotary main shaft driving turntable; the V-shaped positioning block and the clamping device are used to fix the radial stator assembly to be tested on the precision rotary main shaft driving turntable; the precision rotary main shaft driving turntable is used to drive the radial stator assembly to be tested to rotate; d. the tooling shaft motion control assembly is capable of controlling the tooling shaft to enter into the radial stator assembly to be measured; The upper radial sensor has four measuring points, and the phase angles of the four measuring points are 90°, and are recorded as the first to fourth measuring points. The lower radial sensor has four measuring points, and the phase angles of the four measuring points are 90°, and are recorded as the fifth to eighth measuring points. The first measuring point is an X+ measuring point, the second measuring point is a Y+ measuring point, the third measuring point is an X- measuring point, and the fourth measuring point is a Y- measuring point. The fifth measuring point is an X+ measuring point, the sixth measuring point is a Y+ measuring point, the seventh measuring point is an X- measuring point, and the eighth measuring point is a Y- measuring point. The method comprises the following steps: S100, mounting the radial stator assembly to be measured on the precision rotary main shaft driving turntable: the radial stator assembly to be measured is fixed on the precision rotary main shaft driving turntable through the V-shaped positioning block and the clamping device; S200, moving the tooling shaft by the tooling shaft motion control assembly, so that the tooling shaft is inserted into the radial stator assembly to be measured; S300, solving the eccentricity L between the center points of the upper radial sensor and the lower radial sensor; L is the average value of any one or any two of L1, L2, L3 and L4, or the average value of any three or four of L1, L2, L3 and L4; L1 is the eccentricity solved by the fourth and second measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor; L2 is the eccentricity solved by the fourth and second measuring points of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor; L3 is the eccentricity solved by the third and first measuring points of the upper radial sensor and the eighth and sixth measuring points of the lower radial sensor; L4 is the eccentricity solved by the third and first measuring points of the upper radial sensor and the seventh and fifth measuring points of the lower radial sensor; Wherein the eccentricity L is solved by the pth and qth measuring points of the upper radial sensor and the mth and nth measuring points of the lower radial sensor s The method comprises the following sub-steps: S401, test delta 短 p, delta 短q , delta 短 m, delta 短 n, delta 长 p, delta 长q , delta 长 m, delta 长 n, D 测p , D 测q , D 测m , D 测n ; For any δ 短i , δ 长i , D 测i , i is any value of p, q, m, n, which is obtained as follows: The precision rotary main shaft drives the rotary table to rotate one circle with the radial stator assembly to be measured, and in the process, the minimum value of the distance measured by the ith measuring point is δ 短i , and the maximum value of the distance is δ 长i ; D 测i =δ 短i +δ 长i +D0,D 测i denotes the rotational diameter of the i-th measuring point, D0denotes the diameter of the tool shaft; S402, test β pq , β mq , β nq : for any β vq , refers to the included angle between AQ and AV counterclockwise, wherein v is any value of p, m, n; A, Q, V represent the projection points of the rotation axis of the precision rotary main shaft driving rotary table, the qth measuring point and the vth measuring point in the same horizontal plane respectively; and the testing method is as follows: Step a, rotate the precision rotary main shaft drive turntable so that the minimum value of the distance measured by the vth measuring point is taken as the starting point, and the precision rotary main shaft drive turntable is rotated clockwise until the minimum value of the distance measured by the qth measuring point is taken as the end point. The angle rotated between the starting point and the end point is recorded as β vq-顺 ; Step b, rotate the precision rotary main shaft drive turntable so that the minimum value of the distance measured by the vth measuring point is taken as the starting point, and the precision rotary main shaft drive turntable is counterclockwise rotated until the minimum value of the distance measured by the qth measuring point is taken as the end point. The angle rotated between the starting point and the end point is recorded as β vq-逆 ; β vq =β vq-逆 -（β vq-顺+ β vq-逆 -360°） / 2； S403, solving L s : L s = 0.5 x ((D 测m · cos β mq + D 测n · cos β nq − D 测q − D 测p · cos β pq ) 2 + (D 测m · sin β mq + D 测n · sin β nq − D 测p · sin β pq ) 2 ) 0.5 .

3. The method of claim 2, wherein the method further comprises: The high-precision rotary platform assembly further comprises an angle sensor; the angle sensor is used to measure the rotation angle of the precision rotary main shaft driving turntable.

4. The method of claim 2, wherein the method further comprises: The rotation axis of the precision rotary main shaft driving turntable is coaxial with the rotation axis of the bearing seat of the radial stator assembly to be measured.

5. The method of claim 2, wherein the method further comprises: The tooling shaft motion control assembly is also capable of controlling the tooling shaft to move in the horizontal direction.

6. The method of claim 2, wherein the method is a method of detecting concentricity of a radial sensor of a magnetic levitation molecular pump. The difference between the diameter of the inner cylindrical surface of the upper radial sensor of the radial stator assembly and the diameter of the outer surface of the tooling shaft is 2 mm.

7. The method of claim 2, wherein the method further comprises: The tooling shaft motion control assembly is capable of controlling the tooling shaft to extend into the lower part of the lower radial sensor of the radial stator assembly to be measured, so that the upper radial sensor and the lower radial sensor of the radial stator assembly to be measured can both measure data.

8. The method of claim 2, wherein the method is a method of detecting concentricity of a radial sensor of a magnetic levitation molecular pump. S200 further comprises: rotating the precision rotary main shaft driving turntable with the radial stator assembly to be measured, and performing rotation mechanism running-in.

9. A method for detecting the concentricity eligibility of a radial sensor of a magnetic levitation molecular pump, characterized in that, The concentricity of the upper radial sensor and the lower radial sensor of the radial stator assembly to be measured is tested at least twice; In each detection, the position of the tooling shaft is different, that is, the motion control assembly moves the tooling shaft to different positions, and the concentricity of the upper radial sensor and the lower radial sensor of the radial stator assembly to be measured is tested by using the magnetic suspension molecular pump radial sensor concentricity detection method in claim 1 or 2. If the eccentricity L detected each time is less than the eccentricity threshold [L], it indicates that the concentricity of the magnetic suspension molecular pump radial sensor is qualified; otherwise, it is unqualified.

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