TWI787770B - Magnetic levitation type rotor device and method for calibrating axial levitation height of the same - Google Patents

Abstract

A magnetic levitation type rotor device and a method for calibrating an axial levitation height of the same are provided. The magnetic levitation type rotor device includes a rotor element, a floating plate assembly, at least one axial magnetic bearing, an axial position sensor, and a processor. The floating plate assembly is disposed at a bottom of the rotor element, and includes a floating plate and a metal member connected to the floating plate. The at least one axial magnetic bearing is in proximity to the floating plate. The axial position sensor is arranged beneath the metal member. The processor is electrically connected to the axial position sensor. In use, the position of an induction coil of the axial position sensor can be adjusted to change a vertical distance between the induction coil and the metal member. Therefore, a floating height error of the rotor device can be effectively reduced, and the rotor device can work in a stable state.

Description

Magnetic levitation rotor device and its axial floating height correction method

The invention relates to a rotor device, in particular to a magnetic levitation rotor device and an axial floating height correction method thereof.

Magnetic bearings are bearings that support the rotating shaft of pumps (such as turbomolecular pumps) in a non-contact manner. But it is difficult to control the rotor at the proper height position to ensure the smooth and reliable operation of the pump.

In addition, magnetic bearings have different structural components according to the designs of different manufacturers, and the requirements for assembly precision are relatively high. Once human-made assembly errors occur, it is easy to cause deviations in the floating position of the rotor; Cause heavy work or product scrapping.

The technical problem to be solved by the present invention is to provide a magnetic levitation rotor device for the deficiencies of the prior art, which can achieve precise control of the axial floating height, thereby ensuring operational stability. Furthermore, a method for correcting the axial floating height of the magnetic levitation rotor device is provided.

In order to solve the above-mentioned technical problems, one of the technical solutions adopted by the present invention is to provide an axial floating height correction method for a magnetic levitation rotor device, which includes: a rotor element; a floating plate assembly arranged on the rotor The bottom of the element, and includes a floating plate and a metal piece connected to the floating plate; at least one axial magnetic bearing, arranged near the floating plate; an axial position sensor, arranged below the metal piece and a controller electrically connected to the axial position sensor. The axial floating height correction method includes: step A: driving the floating plate through the at least one axial magnetic bearing, so that the rotor element is at a floating height; step B: obtaining the same value as the axial position sensor through the axial position sensor An electrical signal related to the buoyant height; step C: judge whether the buoyant height reaches an allowable height range through the controller according to the electrical signal; and step D: if the buoyant height does not reach the allowable height range, Then adjust the position of an induction coil of the axial position sensor to change a vertical distance between it and the metal part.

In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a magnetic levitation rotor device, which includes a rotor element, a floating plate assembly, at least one axial magnetic bearing, an axial position sensor and a controller. The floating plate assembly is arranged at the bottom of the rotor element, and includes a floating plate and a metal piece connected to the floating plate. The at least one axial magnetic bearing is disposed adjacent to the buoyant plate and is configured to drive the buoyant plate such that the rotor element is at a buoyant height. The axial position sensor is arranged under the metal part and configured to obtain an electric signal related to the buoyancy height. The controller is electrically connected to the axial position sensor, so as to judge whether the floating height reaches an allowable height range according to the electric signal. If the buoyant height does not reach the allowable height range, the position of an induction coil of the axial position sensor can be adjusted to change a vertical distance between it and the metal part.

Furthermore, the axial floating height correction method further includes: repeating step A to step D until the floating height of the rotor element is within the allowable height range.

Furthermore, the electrical signal obtained by the axial position sensor is an inductance signal or a voltage signal.

Furthermore, the controller is configured to execute the following judgment procedure: judge whether the value corresponding to the electric signal falls within a predetermined value range; if the value corresponding to the electric signal does not fall within the predetermined value range, Then it is judged that the buoyancy height has not reached the allowable height range; if the value corresponding to the electrical signal falls within the predetermined value range, it is judged that the buoyant height has reached the allowable height range.

Furthermore, when the position of the induction coil is adjusted up, the vertical distance is shortened, and the buoyant height is therefore reduced to a certain extent; wherein, when the position of the induction coil is adjusted down, that is The vertical distance is increased and the buoyancy height is thus increased to some extent.

Furthermore, the rotor element includes a rotor shaft, the floating plate and the metal part are connected to a tail end of the rotor shaft, and the metal part fixes the floating plate from below.

One of the beneficial effects of the present invention is that the magnetic levitation rotor device of the present invention and its axial floating height correction method can obtain electrical signals related to the floating height of the rotor element through the "axial position sensor" , and the controller judges whether the lift height of the rotor element reaches the allowable height range according to the obtained electric signal" and "if the lift height of the rotor element does not reach the allowable height range, adjust the induction of the axial position sensor The position of the coil to change the vertical distance between it and the floating plate of the rotor element" technical means, so that the rotor element can be accurately lifted to the desired height, thereby eliminating or reducing the influence of cumulative assembly tolerances, allowing the rotor device in Work in a stable state.

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings related to the present invention. However, the provided drawings are only for reference and description, and are not intended to limit the present invention.

The following is a description of the implementation of the "magnetic levitation rotor device and its axial floating height correction method" disclosed by the present invention through specific specific examples. Those skilled in the art can understand the present invention from the content disclosed in this specification advantages and effects. The present invention can be implemented or applied through other different specific embodiments, and various modifications and changes can be made to the details in this specification based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only for simple illustration, and are not drawn according to the actual size, which is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the protection scope of the present invention. In addition, the term "or" used herein may include any one or a combination of more of the associated listed items depending on the actual situation.

Please refer to FIG. 1 , which is a schematic structural diagram of a turbomolecular pump using a magnetic levitation rotor device R according to an embodiment of the present invention. As shown in FIG. 1 , the magnetic levitation rotor device R mainly includes a rotor element 1 a , a floating plate assembly 2 , at least one axial magnetic bearing 3 , an axial position sensor 4 and a controller 5 . The floating plate assembly 2 is disposed on the bottom of the rotor element 1a, the axial magnetic bearing 3 is disposed near the floating plate assembly 2, the axial position sensor 4 is disposed below the floating plate assembly 2, and the controller 5 is electrically connected to Axial position sensor 4.

In this embodiment, the floating plate assembly 2 includes a floating plate 21 and a metal piece 22 , and the metal piece 22 is connected to the floating plate 21 . Wherein the floating plate 21 has magnetic permeability, and the floating plate 21 can be disc-shaped, but it can also have different shapes; the metal part 22 can be configured to fix the floating plate 21 on the rotor element 1a from below, the metal part 22 It can be a metal screw, but it can also be other forms of metal fixing parts.

The axial magnetic bearing 3 can be configured to drive the floating plate 21 so that the rotor element 1a is at a buoyant height; A magnetic force can be generated between them to drive the rotor element 1a for axial displacement (that is, to push the rotor element 1a in the +Z direction).

The axial position sensor 4 can obtain an electrical signal related to the floating height of the rotor element 1a, which can be an inductive position sensor, that is, the obtained electrical signal is an inductive signal or a voltage signal, but is not limited to this. In other embodiments, the axial position sensor 4 can be other sensors that work on the principle of impedance variation.

The controller 5 can receive the electric signal obtained by the axial position sensor 4, and judge whether the floating height of the rotor element 1a is within an allowable height range or not.

Please refer to FIG. 2 and FIG. 3 , together with FIG. 1 , FIG. 2 and FIG. 3 are schematic diagrams illustrating the operation of the axial position sensor 4 of the magnetic levitation rotor device R according to the embodiment of the present invention. The axial position sensor 4 includes an induction coil 41 (which can be single-layer or multi-layer); before the magnetic levitation rotor device R enters the normal operation mode, if the judging result of the controller 5 is that the lift height of the rotor element 1a has not reached Within the allowable height range, the position of the induction coil 41 is manually adjusted (but not limited to), that is, the induction coil 41 is raised or lowered step by step to change the distance between it and the metal part 22 of the rotor element 1a, thereby realizing Correction of the flying height of the rotor element 1a.

Furthermore, if the judging result of the controller 5 is that the floating height of the rotor element 1a exceeds the upper limit height of the allowable height range, the position of the induction coil 41 can be adjusted up so that there is a gap between it and the floating metal piece 22. A shorter vertical distance D1, as shown in Figure 2, so that the lift height of the rotor element 1a can also be reduced to a certain extent; when the judgment result of the controller 5 is that the lift height of the rotor element 1a is lower than the allowable height When the height of the lower limit of the range is lower, the position of the induction coil 41 can be lowered so that there is a longer vertical distance D2 between it and the metal part 22, as shown in Figure 3, so that the floating height of the rotor element 1a can also be increased. rise to a certain extent.

In actual application, an AC signal (such as a sine wave signal) needs to be applied to the axial position sensor 4; the signal source can be an LCR meter or an eddy current drive circuit. Furthermore, the axial position sensor 4 may include a lifting table 42, which can drive the induction coil 41 to perform axial displacement (ie move in the axial direction of the rotor element 1a) while rotating.

After receiving the electric signal from the axial position sensor 4, the controller 5 executes the following judgment procedure: judge whether the numerical value (such as inductance value) corresponding to the electric signal falls within a predetermined numerical range; If the value falls within the predetermined value range, it is determined that the buoyant height of the rotor element 1a is not within the allowable height range; It should be noted that the rotor element 1a has a variety of specifications and models, and each has a different allowable height range. Therefore, at the beginning of the judgment process, the target specification and model should be selected first to determine the applicable predetermined value range, which can be used alone or in combination with actual conditions. It is determined by operating experience, historical operating data and test data. In actual application, the controller 5 can be a computer or the central controller of a computer system, and the judgment program executed can be an application program installed in the computer or control device, but the present invention is not limited thereto.

Referring back to FIG. 1, the magnetic levitation rotor device R of the present invention can be applied to a turbomolecular pump, wherein the rotor element 1a can rotate relative to a stator element 1b to evacuate a semiconductor process chamber (not shown in the figure), The specific implementation details are described as follows.

The rotor element 1a may include a rotor shaft 11a, a rotor base 12a and a plurality of rotating wings 13a, wherein the rotor shaft 11a passes through the center of the rotor base 12a and is integrated with the rotor base 12a, and the plurality of rotating wings 13a They are fixedly connected to the outer wall of the rotor base 12a in a manner of distributing up and down (arranged in layers). The rotor base 12a, the rotor shaft 11a and the rotor blade 13a can be integrally formed by machining, or can be assembled into one body. In addition, the floating plate 21 and the metal piece 22 can be connected to the tail end of the rotor shaft 11 a and located between the two axial magnetic bearings 3 , wherein the metal piece 22 fixes the floating plate 21 from below.

The stator element 1b may include a plurality of fixed wings 11b and an air guide ring 12b, wherein the plurality of fixed wings 11b are alternately arranged with the plurality of rotating wings 13a, that is, each fixed wing 11b is located in a space between two rotating wings 13a In the gap, the air guide ring 12b is disposed under the rotating wing 13a and the fixed wing 11b, and the air guide ring 12b and the rotor base 12a jointly define an annular gas channel G. Also, each rotary wing 13a includes a plurality of rotor blades arranged radially, and each fixed wing 11b includes a plurality of stator blades arranged radially. Thereby, when the rotor element 1a rotates at a high speed, it can produce the effect of dragging gas, so that the gas enters from the inlet A1 and flows irreversibly to the gas channel G, and then is guided by the gas guide ring 12b to be discharged from the exhaust port A2. In actual application, the gas guide ring 12b may have a threaded groove (not shown in the figure), and the gas may be compressed in the threaded groove.

When applied to a turbomolecular pump, the magnetic levitation rotor device R of the present invention may further include at least one radial magnetic bearing 6 and a motor module 7 . Both the radial magnetic bearing 6 and the motor module 7 are arranged around the rotor shaft 11a, and are separated by a certain distance in the axial direction, wherein the radial magnetic bearing 6 can be configured to control the radial displacement of the rotor shaft 11a, so that the rotor element 1a is located at an appropriate radial position, and the motor module 7 can be configured to drive the rotor element 1a to rotate at a high speed.

Please refer to FIG. 4 , and as shown in FIG. 1 to FIG. 3 , the present invention also provides a method for correcting axial floating height, which can be used in the above-mentioned magnetic levitation rotor device R. The axial floating height correction method of the present invention includes: step S1: driving the rotor element 1a of the magnetic levitation rotor device R, so that the rotor element 1a is at a floating height; An electrical signal related to the lift height; step S3: judge whether the lift height is within the allowable height range according to the obtained electrical signal; and step S4: if the lift height does not reach the allowable height range, adjust the axial position The position of the induction coil 41 of the sensor 4 to correct the lift height of the rotor element 1a.

Furthermore, in step S2, an AC signal (such as a sine wave signal) is applied to the axial position sensor 4, so that the impedance of the induction coil 41 changes (also the magnitude and phase of the current change), so that Obtain an electrical signal reflecting the buoyant height (the distance between the induction coil 41 and the metal piece 22 ), such as an inductance signal or a voltage signal.

In step S3, the controller 5 executes the following judging procedure: judging whether the value corresponding to the electrical signal (such as the inductance value) falls within a predetermined value range; The floating height of the element 1a is not within the allowable height range; if the value falls within the predetermined value range, it is determined that the floating height of the rotor element 1a is within the allowable height range. It should be noted that the rotor element 1a has a variety of specifications and models, and each has a different allowable height range. Therefore, at the beginning of the judgment process, the target specification and model should be selected first to determine the applicable predetermined value range, which can be used alone or in combination with actual conditions. It is determined by operating experience, historical operating data and testing data.

In step S4, if the judging result of the controller 5 is that the floating height of the rotor element 1a exceeds the upper limit height of the allowable height range, the position of the induction coil 41 can be adjusted up so that there is a gap between it and the metal part 22. The shorter vertical distance D1, as shown in Figure 2, can also reduce the lift height of the rotor element 1a to a certain extent; when the judgment result of the controller 5 is that the lift height of the rotor element 1a is lower than the allowable height range When the lower limit height is lower, the position of the induction coil 41 can be lowered so that there is a longer vertical distance D2 between it and the metal part 22, as shown in Figure 3, so that the floating height of the rotor element 1a can also be certain. degree of rise.

[Advantageous Effects of Embodiment]

One of the beneficial effects of the present invention is that the magnetic levitation rotor device of the present invention and its axial floating height correction method can obtain electrical signals related to the floating height of the rotor element through the "axial position sensor" , and the controller judges whether the lift height of the rotor element reaches the allowable height range according to the obtained electric signal" and "if the lift height of the rotor element does not reach the allowable height range, adjust the induction of the axial position sensor The position of the coil to change the vertical distance between it and the floating plate of the rotor element" technical means, so that the rotor element can be accurately lifted to the desired height, thereby eliminating or reducing the influence of cumulative assembly tolerances, allowing the rotor device in Work in a stable state.

In addition, the axial floating height correction method of the present invention is easy to operate, and can adjust the detection parameter range according to different magnetic levitation systems, and has high flexibility in use. Moreover, all calibration results can be recorded and stored as a reference for future quality inspections.

The content disclosed above is only a preferred feasible embodiment of the present invention, and does not therefore limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made by using the description and drawings of the present invention are included in the application of the present invention. within the scope of the patent.

R: Magnetic levitation rotor device 1a: Rotor element 11a: rotor shaft 12a: rotor base 13a: Rotary wing 1b: Stator element 11b: fixed wing 12b: Air guiding ring 2: Floating plate assembly 21: floating board 22: metal parts 3: Axial magnetic bearing 4: Axial position sensor 41: induction coil 42: Lifting platform 5: Controller 6: Radial magnetic bearing 7:Motor module A1: air inlet A2: Exhaust port D1, D2: vertical distance G: gas channel

Fig. 1 is a schematic structural view of a turbomolecular pump applying the magnetic levitation rotor device of the present invention.

FIG. 2 is a schematic diagram of the operation of the axial position sensor of the magnetic levitation rotor device of the present invention.

FIG. 3 is another schematic view of the operation of the axial position sensor of the magnetic levitation rotor device of the present invention.

Fig. 4 is a flow chart of the axial floating height correction method used in the magnetic levitation rotor device of the present invention.

Step S1 to Step S4: Calibration method steps

Claims (10)

A method for correcting axial floating height, which is used for a magnetic levitation rotor device, comprising: a rotor element; a floating plate assembly, which is arranged at the bottom of the rotor element, and includes a floating plate and a metal plate connected to the floating plate parts; at least one axial magnetic bearing disposed near the floating plate; an axial position sensor disposed below the metal part; and a controller electrically connected to the axial position sensor; Among them, the axial buoyancy correction method includes: Step A: driving the buoyant plate through the at least one axial magnetic bearing so that the rotor element is at a buoyant height; Step B: obtaining an electrical signal related to the buoyancy height through the axial position sensor; Step C: judging by the controller according to the electrical signal whether the buoyant height is within an allowable height range; and Step D: If the buoyant height does not reach the allowable height range, then adjust the position of an induction coil of the axial position sensor to change a vertical distance between it and the metal part. The axial floating height correction method as described in Claim 1, wherein, in step B, the electrical signal obtained by the axial position sensor is an inductance signal or a voltage signal. The axial buoyancy correction method as described in claim 2, wherein, in step C, the controller executes the following judging procedure: judging whether the value corresponding to the electric signal falls within a predetermined value range; if the electric signal If the value corresponding to the electrical signal does not fall within the predetermined value range, it is judged that the buoyant height has not reached the allowable height range; if the value corresponding to the electrical signal falls within the predetermined value range, it is judged that the buoyant height The lift height is within the allowable height range. The axial floating height correction method as described in claim 3, wherein, in step D, the position of the induction coil is adjusted up or down; wherein, when the position of the induction coil is adjusted up, the The vertical distance and thus the buoyant height are decreased to a certain extent; wherein, when the position of the induction coil is lowered, the vertical distance is increased, and the buoyant height is therefore increased to a certain extent. The axial floating height correction method according to claim 1, further comprising: repeating step A to step D until the floating height of the rotor element is within the allowable height range. A magnetic levitation rotor device, comprising: a rotor element; A floating plate assembly is arranged at the bottom of the rotor element and includes a floating plate and a metal part connected to the floating plate; at least one axial magnetic bearing disposed adjacent the buoyant plate and configured to drive the buoyant plate such that the rotor element is at a buoyant height; an axial position sensor disposed below the metal member and configured to obtain an electrical signal related to the buoyancy height; and a controller electrically connected to the axial position sensor to judge whether the buoyant height reaches an allowable height range according to the electrical signal; Wherein, if the floating height does not reach the allowable height range, the position of an induction coil of the axial position sensor can be adjusted to change a vertical distance between it and the metal part. The magnetic levitation rotor device as claimed in claim 6, wherein the electrical signal obtained by the axial position sensor is an inductance signal or a voltage signal. The magnetic levitation rotor device as described in claim 7, wherein the controller is configured to execute the following judging procedure: judging whether the value corresponding to the electric signal falls within a predetermined value range; if the value corresponding to the electric signal If it does not fall within the predetermined numerical range, it is judged that the buoyant height has not reached the allowable height range; if the value corresponding to the electrical signal falls within the predetermined numerical range, it is judged that the buoyant height has reached the allowable height height range. The magnetic levitation rotor device as described in Claim 8, wherein, when the position of the induction coil is adjusted up, the vertical distance is shortened, and the buoyant height decreases to a certain extent; wherein, when the induction coil When the position of the coil is lowered, the vertical distance is increased and the buoyancy height is thus increased to some extent. The magnetic levitation rotor device as claimed in claim 8, wherein the rotor element includes a rotor shaft, the floating plate and the metal piece are connected to a tail end of the rotor shaft, and the metal piece fixes the floating plate from below .

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