A magnetic levitation active three-degree-of-freedom bearing, motor and compressor

Abstract

The present invention provides a magnetic levitation active three-degree-of-freedom bearing and a compressor. The magnetic levitation active three-degree-of-freedom bearing includes: an axial magnetic bearing, a radial magnetic bearing, and a bearing rotor. The axial magnetic bearing includes a first axial stator and a second axial stator. The radial magnetic bearing includes a radial stator. The radial stator is located on the outer periphery of the bearing rotor and can apply a radial electromagnetic force to the bearing rotor. The first axial stator and the second axial stator can apply an axial electromagnetic force to the bearing rotor. The bias magnetic flux of the radial magnetic bearing is provided by the axial magnetic bearing. Both the first axial stator and the second axial stator are segmented structures arranged at intervals in the circumferential direction. According to the present invention, the first and second axial stators can effectively provide a bias magnetic path for the radial stator, eliminating the original structures such as a bias stator, etc. The structure is more compact and simple, the process difficulty is reduced, the volume is reduced, and the assembly is easy.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic levitation, and particularly to a magnetic levitation active three-degree-of-freedom bearing, a motor, and a compressor. Background Art

[0002] Magnetic levitation bearings use electromagnetic forces on the rotor to levitate the rotating shaft, keeping the rotating shaft and the stator in a non-contact state, thus having advantages such as no wear, high rotational speed, high precision, and long service life. Magnetic bearings can be classified into three categories according to their working principles: active magnetic bearings, passive magnetic bearings, and hybrid magnetic bearings.

[0003] The active three-degree-of-freedom magnetic bearing in the patent No. CN110017330A, "An Axial-Radial Electromagnetic-Type Magnetic Bearing", has a complex structure. It uses an E-shaped salient pole radial segmented stator to form the bias magnetic flux for the radial bearing. Its processing and manufacturing process are complex, assembly is difficult, and there is magnetic flux leakage in the axial direction of the radial suspension winding.

[0004] Due to the technical problems in the existing magnetic levitation active three-degree-of-freedom bearing, such as forming the bias magnetic flux of the radial bearing by setting a bias stator, resulting in a complex structure, a large volume, a complex process, and difficult assembly, the present invention researches and designs a magnetic levitation active three-degree-of-freedom bearing, a motor, and a compressor. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the existing magnetic levitation active three-degree-of-freedom bearing, which forms the bias magnetic flux of the radial bearing by setting a bias stator, resulting in a complex structure and a large volume, so as to provide a magnetic levitation active three-degree-of-freedom bearing, a motor, and a compressor.

[0006] To solve the above problems, the present invention provides a magnetic levitation active three-degree-of-freedom bearing, which includes:

[0007] Axial magnetic bearings, radial magnetic bearings, and a bearing rotor. The axial magnetic bearings and the radial magnetic bearings are both sleeved on the outer periphery of a rotating shaft. The axial magnetic bearings include a first axial stator and a second axial stator. The radial magnetic bearings include a radial stator. The bearing rotor is sleeved on the outer periphery of the rotating shaft and can rotate together with the rotating shaft. The radial stator is located on the outer periphery of the bearing rotor and can apply a radial electromagnetic force to the bearing rotor. Along the axial direction of the rotating shaft, at least part of the structure of the first axial stator is located at one axial end of the bearing rotor, and at least part of the structure of the second axial stator is located at the other axial end of the bearing rotor. The first axial stator and the second axial stator can apply an axial electromagnetic force to the bearing rotor, and at least part of the structure of the first axial stator is located radially outside the bearing rotor, and at least part of the structure of the second axial stator is located radially outside the bearing rotor, so that the bias magnetic flux of the radial magnetic bearing is provided by the axial magnetic bearing. The first axial stator and the second axial stator are both segmented structures arranged at intervals in the circumferential direction.

[0008] In some embodiments, the structures of the first axial stator and the second axial stator are the same, and both include a first axial stator unit, a second axial stator unit, a third axial stator unit, and a fourth axial stator unit that are sequentially arranged at intervals in the circumferential direction.

[0009] In some embodiments, the radial stator includes a radial iron core and a radial winding. The radial iron core is a ring structure and is sleeved on the radial outer side of the bearing rotor;

[0010] The radial iron core includes a radial stator yoke and radial stator pole columns. The radial stator yoke is a ring structure. The radially outer ends of the radial stator pole columns are connected to the radial stator yoke, and the radially inner ends protrude toward the bearing rotor and have a radial working gap with the bearing rotor. The radial winding is wound around each radial stator pole column;

[0011] And in the radial cross-section, the radial stator includes a first quadrant part located in the upper right, a second quadrant part located in the upper left, a third quadrant part located in the lower left, and a fourth quadrant part located in the lower right. The first quadrant part, the second quadrant part, the third quadrant part, and the fourth quadrant part are sequentially connected counterclockwise. The first quadrant part and the third quadrant part form a diagonal, and the second quadrant part and the fourth quadrant part form a diagonal; the number of the radial stator pole columns is 4n, where n is a natural number.

[0012] In some embodiments, the radial stator pole columns include a second radial magnetic pole and a third radial magnetic pole located in the first quadrant portion, a fourth radial magnetic pole and a fifth radial magnetic pole located in the fourth quadrant portion, a sixth radial magnetic pole and a seventh radial magnetic pole located in the third quadrant portion, and a first radial magnetic pole and an eighth radial magnetic pole located in the second quadrant portion.

[0013] In some embodiments, the magnetic paths inside the first radial magnetic pole, the bearing rotor, the second radial magnetic pole, and the radial stator yoke are connected to form a closed loop, forming a radial bearing magnetic path; the magnetic paths inside the third radial magnetic pole, the bearing rotor, the fourth radial magnetic pole, and the radial stator yoke are also connected to form a closed-loop radial bearing magnetic path; the magnetic paths inside the fifth radial magnetic pole, the bearing rotor, the sixth radial magnetic pole, and the radial stator yoke are also connected to form a closed-loop radial bearing magnetic path; the magnetic paths inside the seventh radial magnetic pole, the bearing rotor, the eighth radial magnetic pole, and the radial stator yoke are also connected to form a closed-loop radial bearing magnetic path.

[0014] In some embodiments, the first axial stator unit faces the first radial magnetic pole and the eighth radial magnetic pole in the second quadrant portion, and provides a bias magnetic path to the first radial magnetic pole and the eighth radial magnetic pole through the first axial stator unit; the second axial stator unit faces the second radial magnetic pole and the third radial magnetic pole in the first quadrant portion, and provides a bias magnetic path to the second radial magnetic pole and the third radial magnetic pole through the second axial stator unit; the third axial stator unit faces the fourth radial magnetic pole and the fifth radial magnetic pole in the fourth quadrant portion, and provides a bias magnetic path to the fourth radial magnetic pole and the fifth radial magnetic pole through the third axial stator unit; the fourth axial stator unit faces the sixth radial magnetic pole and the seventh radial magnetic pole in the third quadrant portion, and provides a bias magnetic path to the sixth radial magnetic pole and the seventh radial magnetic pole through the fourth axial stator unit.

[0015] In some embodiments, the bias magnetic paths provided by the first axial stator unit to the first radial magnetic pole and the eighth radial magnetic pole both extend in the radial direction towards the center of the rotation axis; the bias magnetic paths provided by the second axial stator unit to the second radial magnetic pole and the third radial magnetic pole both extend in the radial direction away from the center of the rotation axis; the bias magnetic paths provided by the third axial stator unit to the fourth radial magnetic pole and the fifth radial magnetic pole both extend in the radial direction towards the center of the rotation axis; the bias magnetic paths provided by the fourth axial stator unit to the sixth radial magnetic pole and the seventh radial magnetic pole both extend in the radial direction away from the center of the rotation axis.

[0016] In some embodiments, the first axial stator includes a first axial iron core and a first axial winding. The first axial iron core is of an annular structure and includes a first main body portion, a first annular portion, and a second annular portion. The first main body portion is a disc structure having a first central hole for receiving the rotating shaft to pass through. The second annular portion is located radially outside the first annular portion. One end of the first annular portion is connected to the first main body portion and the other end extends towards the bearing rotor to be opposite to the bearing rotor. One end of the second annular portion is connected to the first main body portion and the other end extends towards the radial iron core to be opposite to the radial iron core, so as to form a first accommodation groove between the radially outer side of the first annular portion and the radially inner side of the second annular portion. The first axial winding is wound around the second annular portion.

[0017] In some embodiments, the first annular portion extends along the axial direction of the rotating shaft and is spaced from the bearing rotor by a third preset distance to form a first axial working gap; the second annular portion also extends along the axial direction of the rotating shaft and is spaced from the radial iron core by a fourth preset distance to form a second axial working gap.

[0018] In some embodiments, the second axial stator includes a second axial iron core and a second axial winding. The second axial iron core is of an annular structure and includes a second main body portion, a third annular portion, and a fourth annular portion. The second main body portion is a disc structure having a second central hole for receiving the rotating shaft to pass through. One end of the third annular portion is connected to the second main body portion and the other end extends towards the bearing rotor to be opposite to the bearing rotor. One end of the fourth annular portion is connected to the second main body portion and the other end extends towards the radial iron core to be opposite to the radial iron core, and the fourth annular portion is located radially outside the third annular portion, so as to form a second accommodation groove between the radially outer side of the third annular portion and the radially inner side of the fourth annular portion. The second axial winding is wound around the fourth annular portion.

[0019] In some embodiments, the third annular portion extends along the axial direction of the rotating shaft and is spaced from the bearing rotor by a fifth preset distance to form a first axial working gap; the fourth annular portion also extends along the axial direction of the rotating shaft and is spaced from the radial iron core by a sixth preset distance to form a second axial working gap.

[0020] In some embodiments, the energization directions of the first axial winding and the second axial winding are opposite; the radial winding is simultaneously located radially outside the second annular portion and the fourth annular portion, and both the second annular portion and the fourth annular portion are opposite to the radial stator poles.

[0021] The present invention also provides a motor, which includes the magnetic levitation active three-degree-of-freedom bearing described in any one of the preceding items.

[0022] The present invention also provides a compressor, which includes the magnetic levitation active three-degree-of-freedom bearing described in any one of the preceding items.

[0023] The magnetic levitation active three-degree-of-freedom bearing, motor and compressor provided by the present invention have the following beneficial effects:

[0024] 1. Through the effective arrangement of the axial magnetic bearing and the radial magnetic bearing, the radial stator is located on the outer periphery of the bearing rotor and can apply a radial electromagnetic force to the bearing rotor. At least part of the structure of the first axial stator is located at one axial end of the bearing rotor, and at least part of the structure of the second axial stator is located at the other axial end of the bearing rotor. Axial electromagnetic force can be applied to the bearing rotor through the first axial stator and the second axial stator, so that the bearing rotor can be subjected to a radial electromagnetic force by the radial stator to adjust the radial offset of the rotating shaft. At the same time, the bearing rotor can be subjected to an axial electromagnetic force by the first and second axial stators to adjust the axial offset of the rotating shaft, and finally the purpose of realizing radial and axial support for the rotating shaft is achieved. The bias magnetic flux of the radial magnetic bearing is provided by the axial magnetic bearing. Compared with the existing active three-degree-of-freedom magnetic levitation bearing that needs to set structures such as bias stators to provide a bias magnetic path for the radial bearing, through the above structure setting of the present invention, the first and second axial stators can effectively provide a bias magnetic path for the radial stator, eliminating the original structures such as bias stators, with a more compact and simple structure, reduced process difficulty, reduced volume, and easy assembly; the present invention effectively combines the radial magnetic bearing and the axial magnetic bearing together to form an integrated axial and radial magnetic bearing structure. Compared with the existing separate axial magnetic bearing and radial magnetic bearing in the prior art that need to separately set a thrust bearing for the axial magnetic bearing to provide an axial force for the rotating shaft and need to set a radial magnetic bearing rotor for the radial magnetic bearing, the structure of the thrust bearing is effectively eliminated, effectively reducing and shortening the axial dimension of the rotor, integrating the radial bearing and the axial bearing, without a thrust disk, with a compact structure, reduced bearing size, shortened rotor length, increased rotor critical speed, and improved stability and applicability of the magnetic levitation system; by providing a bias magnetic path for the radial stator through the axial stator, the present invention can effectively eliminate the structure of the permanent magnet compared with the hybrid magnetic levitation bearing, with low cost, convenient assembly, large bearing capacity, and can operate at high power; the present invention also makes the axial stator poles into a segmented structure, which can effectively reduce and avoid the magnetic leakage phenomenon of the radial magnetic path on the outer circle of the axial stator, thereby effectively enhancing the air-gap magnetic field on the radial poles, improving the control magnetic flux, increasing the radial output force, and improving the control performance;

[0025] 2. The present invention also arranges the radial windings on the radial outer sides of the first axial iron core and the second axial iron core, and both the second annular portion and the fourth annular portion face the radial stator pole columns. Compared with the existing solution where the upper magnetic pole of the axial stator is located beside the radial stator yoke (i.e., the upper magnetic pole of the existing axial stator is located on the axial side of the radial stator yoke), it can effectively reduce the magnetic leakage of the radial magnetic circuit in the axial direction and effectively prevent the uneven circumferential distribution of the axial output force. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is an exploded structural view of the magnetic levitation active three - degree - of - freedom bearing of the present invention;

[0027] Figure 2 is a cross - sectional structural view of the magnetic levitation active three - degree - of - freedom bearing of the present invention (radial section, radial magnetic circuit of the three - degree - of - freedom bearing);

[0028] Figure 3 is a longitudinal sectional structural view of the magnetic levitation active three - degree - of - freedom bearing of the present invention ( Figure 2 A - A sectional axial section, axial magnetic circuit of the three - degree - of - freedom bearing);

[0029] Figure 4 is Figure 3 a mating structural view of the upper half of the axial stator, radial stator and bearing rotor in

[0030] Figure 5 is a longitudinal sectional structural view of the magnetic levitation active three - degree - of - freedom bearing of the present invention ( Figure 2 B - B sectional axial section, axial magnetic circuit of the three - degree - of - freedom bearing);

[0031] Figure 6 is a cross - sectional schematic view of the axial stator of the magnetic levitation active three - degree - of - freedom bearing of the present invention.

[0032] The reference numerals are shown as:

[0033] 100, Axial magnetic bearing; 300, First axial stator; 1, Radial stator yoke; 2, Rotating shaft; 3, Radial bearing magnetic circuit; 31, Upper radial bearing magnetic circuit at section A; 32, Lower radial bearing magnetic circuit at section A; 4, Axial bearing magnetic circuit; 41, Upper axial bearing magnetic circuit at section A; 42, Lower axial bearing magnetic circuit at section A; 43, Upper axial bearing magnetic circuit at section B; 44, Lower axial bearing magnetic circuit at section B; 6, First axial iron core; 6a, First main body part; 6b, First annular part; 6c, Second annular part; 6d, First receiving groove; 61, First axial stator unit; 62, Second axial stator unit; 63, Third axial stator unit; 64, Fourth axial stator unit; 7, First axial winding; 400, Second axial stator; 11, Second axial iron core; 11a, Second main body part; 11b, Third annular part; 11c, Fourth annular part; 11d, Second receiving groove; 12, Second axial winding; 200, Radial magnetic bearing; 500, Radial stator; 5, Radial winding; 9, Bearing rotor; 10, Radial iron core; 8, Radial stator pole column; 81, First radial magnetic pole; 82, Second radial magnetic pole; 83, Third radial magnetic pole; 84, Fourth radial magnetic pole; 85, Fifth radial magnetic pole; 86, Sixth radial magnetic pole; 87, Seventh radial magnetic pole; 88, Eighth radial magnetic pole; 15, Radial working gap; 16, First axial working gap; 19, Second axial working gap. Detailed implementation manners

[0034] As Figures 1-6 shown, the present invention provides a magnetic levitation active three - degree - of - freedom bearing, which includes:

[0035] An axial magnetic bearing 100, a radial magnetic bearing 200, and a bearing rotor 9. The axial magnetic bearing 100 and the radial magnetic bearing 200 are both sleeved on the outer periphery of a rotating shaft 2. The axial magnetic bearing 100 includes a first axial stator 300 and a second axial stator 400. The radial magnetic bearing 200 includes a radial stator 500. The bearing rotor 9 is sleeved on the outer periphery of the rotating shaft 2 and can rotate together with the rotating shaft 2. The radial stator 500 is located on the outer periphery of the bearing rotor 9 and can apply a radial electromagnetic force to the bearing rotor 9. Along the axial direction of the rotating shaft 2, at least part of the structure of the first axial stator 300 is located at one axial end of the bearing rotor 9, and at least part of the structure of the second axial stator 400 is located at the other axial end of the bearing rotor 9. The first axial stator 300 and the second axial stator 400 can apply an axial electromagnetic force to the bearing rotor 9, so that the bias magnetic flux of the radial magnetic bearing 200 is provided by the axial magnetic bearing 100. Both the first axial stator 300 and the second axial stator 400 are block - like structures arranged at intervals in the circumferential direction.

[0036] Through the effective arrangement of the axial magnetic bearing and the radial magnetic bearing, the radial stator is located on the outer periphery of the bearing rotor and can apply a radial electromagnetic force to the bearing rotor. At least part of the structure of the first axial stator is located at one axial end of the bearing rotor, and at least part of the structure of the second axial stator is located at the other axial end of the bearing rotor. The axial electromagnetic force can be applied to the bearing rotor through the first axial stator and the second axial stator, so that the bearing rotor can be applied with a radial electromagnetic force by the radial stator to adjust the radial offset of the rotating shaft. At the same time, the bearing rotor can be applied with an axial electromagnetic force by the first and second axial stators to adjust the axial offset of the rotating shaft. Finally, the purpose of realizing radial and axial support for the rotating shaft is achieved, and the bias magnetic flux of the radial magnetic bearing is provided by the axial magnetic bearing. Compared with the existing active three-degree-of-freedom magnetic suspension bearing that needs to set structures such as a bias stator to provide a bias magnetic path for the radial bearing, through the above structure setting of the present invention, the first and second axial stators can effectively provide a bias magnetic path for the radial stator, eliminating the original structures such as the bias stator. The structure is more compact and simple, the process difficulty is reduced, the volume is reduced, and the assembly is easy; the present invention effectively combines the radial magnetic bearing and the axial magnetic bearing together to form an integrated axial and radial magnetic bearing structure. Compared with the existing separate axial magnetic bearing and radial magnetic bearing in the prior art that need to separately set a thrust bearing for the axial magnetic bearing to provide an axial force for the rotating shaft and need to set a radial magnetic bearing rotor for the radial magnetic bearing, the structure of the thrust bearing is effectively eliminated, the axial dimension of the rotor is effectively reduced and shortened, the radial bearing and the axial bearing are integrated, there is no thrust disc, the structure is compact, the bearing size is reduced, the rotor length is shortened, the critical speed of the rotor is increased, and the stability and applicability of the magnetic suspension system are improved; through the axial stator providing a bias magnetic path for the radial stator, the present invention can effectively eliminate the structure of the permanent magnet compared with the hybrid magnetic suspension bearing, with low cost, convenient assembly, large bearing capacity, and can operate at high power; by making the axial stator magnetic poles into a segmented structure, the present invention can effectively reduce and avoid the magnetic leakage phenomenon of the radial magnetic path on the outer circle of the axial stator, thereby effectively enhancing the air-gap magnetic field on the radial magnetic poles, improving the control magnetic flux, increasing the radial output force, and improving the control performance.

[0037] In some embodiments, the first axial stator 300 and the second axial stator 400 have the same structure, and both include a first axial stator unit 61, a second axial stator unit 62, a third axial stator unit 63, and a fourth axial stator unit 64 that are sequentially arranged at intervals in the circumferential direction. This is the preferred segmented form of the axial stator of the present invention, that is, a plurality of axial stator units are formed at intervals in the circumferential direction, which can enable a single axial stator unit to form a magnetic flux closed loop with some pole columns of the radial stator. While providing a bias magnetic flux for the radial stator, it can also effectively prevent the magnetic leakage phenomenon of the magnetic circuit of the radial stator on the outer circle of the axial stator, thereby improving the radial output and improving the radial control performance.

[0038] 1. The present invention provides a radial / axial integrated three-degree-of-freedom control active magnetic bearing structure; the thrust disk is removed and replaced by a bearing rotor, and the radial bearing and the axial bearing are integrated. Compared with the conventional active magnetic bearing, there is no need to install a thrust disk, the structure is compact, and the process is simple; compared with the usual hybrid three-degree-of-freedom magnetic bearing, there is no permanent magnet, and the bias magnetic field and the control magnetic field are provided by electromagnetic force, with large bearing capacity, high stiffness, and flexible control. This three-degree-of-freedom magnetic bearing can operate at high power and has a high critical speed, improving the stability and applicability of the magnetic levitation system.

[0039] 2. The present invention also provides two methods for energizing the bearing coils. A-A and B-B are one method of energization, and the other method of energization is to make the axial energization completely opposite, aiming to control the radial movement of the rotor, improve the radial output, and improve the working efficiency of magnetic levitation.

[0040] The present invention solves the following technical problems:

[0041] 1. Integrate the radial bearing and the axial bearing, without a thrust disk, with a compact structure, reducing the bearing size, shortening the rotor length, increasing the rotor critical speed, and improving the stability and applicability of the magnetic levitation system.

[0042] 2. When the axial magnetic pole is located at the lower end of the radial stator, magnetic leakage of the radial magnetic circuit on the outer circle of the axis is likely to occur, reducing the radial output.

[0043] In some embodiments, the radial stator 500 includes a radial iron core 10 and a radial winding 5. The radial iron core 10 is of an annular structure and is sleeved on the radial outer side of the bearing rotor 9;

[0044] The radial iron core 10 includes a radial stator yoke 1 and radial stator pole columns 8. The radial stator yoke 1 is of an annular structure. The radially outer ends of the radial stator pole columns are connected to the radial stator yoke 1, and the radially inner ends protrude toward the bearing rotor 9 and have a radial working gap 15 with the bearing rotor 9. Each radial stator pole column is wound with the radial winding 5;

[0045] And in the radial cross-section, the radial stator 500 includes a first quadrant portion located in the upper right, a second quadrant portion located in the upper left, a third quadrant portion located in the lower left, and a fourth quadrant portion located in the lower right. The first quadrant portion, the second quadrant portion, the third quadrant portion, and the fourth quadrant portion are connected in sequence counterclockwise. The first quadrant portion and the third quadrant portion form a diagonal, and the second quadrant portion and the fourth quadrant portion form a diagonal. The number of the radial stator pole columns is 4n, where n is a natural number.

[0046] This is the preferred structural form of the radial stator of the present invention. Through the radial stator pole columns and the radial stator yoke, a small closed-loop magnetic flux and a large closed-loop magnetic flux can be formed with the bearing rotor, so as to provide radial magnetic force for the bearing rotor. The distribution form of the 4 quadrants and the number of the radial stator pole columns are the preferred distribution forms of the present invention. The present invention is preferably 8 poles, that is, 8 radial stator pole columns.

[0047] The present invention further preferably has the same circumferential width for multiple radial stator pole columns, that is, the formed radial magnetic fluxes are the same.

[0048] In some embodiments, the radial stator pole column 8 includes a second radial magnetic pole 82 and a third radial magnetic pole 83 located in the first quadrant portion, a fourth radial magnetic pole 84 and a fifth radial magnetic pole 85 located in the fourth quadrant portion, a sixth radial magnetic pole 86 and a seventh radial magnetic pole 87 located in the third quadrant portion, and a first radial magnetic pole 81 and an eighth radial magnetic pole 88 located in the second quadrant portion.

[0049] This is the further preferred structural form of the radial stator pole column of the present invention, that is, two radial magnetic poles are distributed in the first quadrant portion, two magnetic poles are distributed in the second quadrant, two magnetic poles are distributed in the third quadrant, and two magnetic poles are distributed in the fourth quadrant, forming an 8-pole radial bearing, with simple processing and manufacturing process and convenient radial magnetic circuit control.

[0050] In some embodiments, the magnetic paths inside the first radial magnetic pole 81, the bearing rotor 9, the second radial magnetic pole 82, and the radial stator yoke 1 are connected to form a closed loop, forming a radial bearing magnetic path 3; the magnetic paths inside the third radial magnetic pole 83, the bearing rotor 9, the fourth radial magnetic pole 84, and the radial stator yoke 1 are also connected to form a closed-loop radial bearing magnetic path 3; the magnetic paths inside the fifth radial magnetic pole 85, the bearing rotor 9, the sixth radial magnetic pole 86, and the radial stator yoke 1 are also connected to form a closed-loop radial bearing magnetic path 3; the magnetic paths inside the seventh radial magnetic pole 87, the bearing rotor 9, the eighth radial magnetic pole 88, and the radial stator yoke 1 are also connected to form a closed-loop radial bearing magnetic path 3. The present invention further preferably enables a closed-loop magnetic flux to be formed between the first radial magnetic pole in the second quadrant and the second radial magnetic pole in the first quadrant, capable of providing a radially inward magnetic flux on the first radial magnetic pole and a radially outward magnetic flux on the second radial magnetic pole. The same applies to the magnetic poles in the third and fourth quadrants, so that the radial magnetic flux provided by the pole columns in the first quadrant is the same as the radial magnetic flux provided by the pole columns in the third quadrant, the direction of the radial magnetic flux provided by the pole columns in the first quadrant is opposite to that provided by the pole columns in the second quadrant, and the radial magnetic flux provided by the pole columns in the second quadrant is the same as the radial magnetic flux provided by the pole columns in the third quadrant; an axial bias magnetic flux is formed to enhance or weaken the radial magnetic flux in any quadrant uniformly.

[0051] In some embodiments, the first axial stator unit 61 faces (covers) the first radial magnetic pole 81 and the eighth radial magnetic pole 88 in the second quadrant portion, and provides a bias magnetic path for the first radial magnetic pole 81 and the eighth radial magnetic pole 88 through the first axial stator unit 61; the second axial stator unit 62 faces the second radial magnetic pole 82 and the third radial magnetic pole 83 in the first quadrant portion, and provides a bias magnetic path for the second radial magnetic pole 82 and the third radial magnetic pole 83 through the second axial stator unit 62; the third axial stator unit 63 faces (covers) the fourth radial magnetic pole 84 and the fifth radial magnetic pole 85 in the fourth quadrant portion, and provides a bias magnetic path for the fourth radial magnetic pole 84 and the fifth radial magnetic pole 85 through the third axial stator unit 63; the fourth axial stator unit 64 faces the sixth radial magnetic pole 86 and the seventh radial magnetic pole 87 in the third quadrant portion, and provides a bias magnetic path for the sixth radial magnetic pole 86 and the seventh radial magnetic pole 87 through the fourth axial stator unit 64.

[0052] This is the preferred distribution and corresponding relationship between the segmented axial stator unit of the present invention and multiple radial magnetic poles, that is, the first axial stator unit faces the radial magnetic poles in the second quadrant to provide bias magnetic flux thereto, the second axial stator unit faces the radial magnetic poles in the first quadrant to provide bias magnetic flux thereto, the third axial stator unit faces the radial magnetic poles in the fourth quadrant to provide bias magnetic flux thereto, and the fourth axial stator unit faces the radial magnetic poles in the third quadrant to provide bias magnetic flux thereto.

[0053] In some embodiments, the bias magnetic paths provided by the first axial stator unit 61 to the first radial magnetic pole 81 and the eighth radial magnetic pole 88 both extend in the radial direction towards the center of the rotating shaft 2; the bias magnetic paths provided by the second axial stator unit 62 to the second radial magnetic pole 82 and the third radial magnetic pole 83 both extend in the radial direction away from the center of the rotating shaft 2; the bias magnetic paths provided by the third axial stator unit 63 to the fourth radial magnetic pole 84 and the fifth radial magnetic pole 85 both extend in the radial direction towards the center of the rotating shaft 2; and the bias magnetic paths provided by the fourth axial stator unit 64 to the sixth radial magnetic pole 86 and the seventh radial magnetic pole 87 both extend in the radial direction away from the center of the rotating shaft 2.

[0054] This is the further preferred magnetic flux relationship between the axial stator unit of the present invention and the radial magnetic poles in different quadrants, that is, the bias magnetic fluxes provided by the first axial stator unit and the third axial stator unit are directed towards the radial outer side, and the bias magnetic fluxes provided by the second axial stator unit and the fourth axial stator unit are directed towards the radial inner side. Combining with the distribution form of the radial magnetic poles in different quadrants of the present invention as described above, the radial magnetic fluxes provided by the radial pole columns in each quadrant are in the same direction as the bias radial magnetic fluxes provided by the segmented axial stator units in that quadrant (i.e., both are directed towards the radial inner side or both are directed towards the radial outer side), so that the finally formed radial output force is effectively enhanced. The present invention can maximize the enhancement of the radial output force, improve the effect of the magnetic suspension bearing, and improve the efficiency through such different distribution forms and energization methods of the segmented axial stator and the radial pole columns.

[0055] The structure of the active three-degree-of-freedom magnetic bearing of the present invention is as Figure 1 shown. Compared with the traditional active magnetic bearing structure, the thrust disk is removed and replaced by the bearing rotor. The axial stator is located at both ends of the radial stator, and the radial bearing and the axial bearing are integrated. This structure is mainly composed of parts such as a radial stator yoke 1; a bearing rotor 9; a radial winding 5; a first axial iron core 6; a first axial winding 7; a second axial iron core 11; a second axial winding 12; and a radial bearing stator magnetic pole (radial stator pole column 8).

[0056] In this structure, the radial bearing magnetic poles are arranged in the form of SNNS. If the axial bearing is a complete circle, the axial bearing will partially cancel and partially enhance the magnetic flux of the radial magnetic circuit, resulting in inconsistent coupling of each magnetic pole of the radial bearing, and thus it is difficult to control the output force. In this structure, the axial bearing is divided into blocks. As shown in Figure 2 the two axial bearing blocks shown in the A-A section and the two axial bearing blocks shown in the B-B section in will both enhance the magnetic flux of the corresponding radial magnetic circuit. In this way, the mutual influence between the axial magnetic flux and the radial magnetic flux will be smaller, so as to reduce the overall volume of the bearing while minimizing the control difficulty.

[0057] The flow direction of the magnetic circuit of the first radial bearing in this structure is: the first radial magnetic pole 81 → the bearing rotor 9 → the second radial magnetic pole 82 → the radial stator yoke 1 → the first radial magnetic pole 81 (circulation). The number of this circulation is half of the number of the stator magnetic poles of the radial bearing (the radial stator pole columns 8). The number of the radial stator pole columns 8 is a, a ≥ 4 and is an even number. In the present invention, it is preferably 8.

[0058] The flow direction of the magnetic circuit of the axial bearing in this structure is: in the A section, the first axial iron core 6 → the first radial magnetic pole 81 → the bearing rotor 9 → the first axial iron core 6 (circulation); in the B section, the first axial iron core 6 → the second radial magnetic pole 82 → the bearing rotor 9 → the first axial iron core 6 (circulation), and the same applies to other sections.

[0059] The magnetic poles of the first axial stator unit 61 cover the first radial magnetic pole 81 and the eighth radial magnetic pole 88; the magnetic poles of the second axial stator unit 62 cover the second radial magnetic pole 82 and the third radial magnetic pole 83; the magnetic poles of the third axial stator unit 63 cover the fourth radial magnetic pole 84 and the fifth radial magnetic pole 85; the magnetic poles of the fourth axial stator unit 64 cover the sixth radial magnetic pole 86 and the seventh radial magnetic pole 87.

[0060] When controlling this bearing, separate control of the radial and axial directions can still be achieved. The method is simple, and the azimuth of the radial movement of the control shaft is wide. For this three-degree-of-freedom magnetic bearing, the radial bearing and the axial bearing are integrated, the rotor length is shortened, the critical speed of the rotor is increased, the magnetic poles of the axial bearing are divided into blocks, the magnetic leakage phenomenon of the radial magnetic circuit on the outer circle of the axial stator is avoided, the air-gap magnetic field on the radial magnetic poles is enhanced, and stable suspension in the radial direction is achieved.

[0061] In some embodiments, the first axial stator 300 includes a first axial iron core 6 and a first axial winding 7. The first axial iron core 6 is of an annular structure and includes a first main body portion 6a, a first annular portion 6b, and a second annular portion 6c. The first main body portion 6a is of a disc structure having a first central hole through which the rotating shaft 2 passes. The second annular portion 6c is located radially outside the first annular portion 6b. One end of the first annular portion 6b is connected to the first main body portion 6a and the other end extends towards the bearing rotor 9 to face the bearing rotor 9. One end of the second annular portion 6c is connected to the first main body portion 6a and the other end extends towards the radial iron core 10 to face the radial iron core 10, so as to form a first receiving groove 6d between the radially outer side of the first annular portion 6b and the radially inner side of the second annular portion 6c. The first axial winding 7 is wound around the second annular portion 6c.

[0062] This is a preferred structural form of the first axial stator of the present invention. The first receiving groove for arranging the first axial winding can be formed by the first annular portion and the second annular portion. The first annular portion faces the bearing rotor to allow the magnetic path to pass through. The second annular portion faces the radial iron core, which can effectively improve the radial iron core and the second annular portion, so that the second annular portion, the radial iron core, the bearing rotor, the first annular portion, and the first main body portion form a closed-loop magnetic path. Such a structure can enable the first axial stator to provide a radial bias magnetic flux for the radial stator, so that the first axial stator and the radial stator are integrated into an integral structure, effectively eliminating structures such as a thrust disc, a permanent magnet, and a bias stator, with a compact structure and an effectively reduced volume.

[0063] In some embodiments, the first annular portion 6b extends along the axial direction of the rotating shaft 2 and is spaced from the bearing rotor 9 by a third preset distance to form a first axial working gap 16. The second annular portion 6c also extends along the axial direction of the rotating shaft 2 and is spaced from the radial iron core 10 by a fourth preset distance to form a second axial working gap 19. This is a preferred structural form of the first annular portion and the second annular portion of the present invention, that is, the first annular portion extends axially and forms a first axial working gap with the bearing rotor, so that a magnetic flux can pass between the first annular portion and the bearing rotor, and the first annular portion does not rotate with the bearing rotor. The second annular portion is spaced from the radial iron core by a second axial working gap, so that a magnetic flux can pass between the second annular portion and the radial iron core, and no friction or magnetic leakage is formed between the second annular portion and the radial stator.

[0064] In some embodiments, the second axial stator 400 includes a second axial iron core 11 and a second axial winding 12. The second axial iron core 11 is of an annular structure and includes a second main body portion 11a, a third annular portion 11b, and a fourth annular portion 11c. The second main body portion 11a is of a disc structure having a second central hole, and the second central hole accommodates the rotation shaft 2 passing therethrough. One end of the third annular portion 11b is connected to the second main body portion 11a and the other end extends toward the bearing rotor 9 to be opposite to the bearing rotor 9. One end of the fourth annular portion 11c is connected to the second main body portion 11a and the other end extends toward the radial iron core 10 to be opposite to the radial iron core 10, and the fourth annular portion 11c is located radially outside the third annular portion 11b to form a second accommodation groove 11d between the radially outer side of the third annular portion 11b and the radially inner side of the fourth annular portion 11c. The second axial winding 12 is wound around the fourth annular portion 11c.

[0065] This is a preferred structural form of the second axial stator of the present invention. The second accommodation groove for arranging the second axial winding can be formed by the third annular portion and the fourth annular portion. The third annular portion is opposite to the bearing rotor to accommodate the magnetic path passing through. The fourth annular portion is opposite to the radial iron core, which can effectively improve the radial iron core and the fourth annular portion, so that a closed-loop magnetic path is formed among the fourth annular portion, the radial iron core, the bearing rotor, the third annular portion, and the second main body portion. Such a structure can enable the second axial stator to provide a radial bias magnetic flux for the radial stator, so that the second axial stator and the radial stator are integrated into an integral structure, effectively eliminating structures such as a thrust disc, a permanent magnet, and a bias stator, with a compact structure and an effectively reduced volume.

[0066] In some embodiments, the third annular portion 11b extends along the axial direction of the rotation shaft 2 and is spaced from the bearing rotor 9 by a fifth preset distance to form a first axial working gap 16; the fourth annular portion 11c also extends along the axial direction of the rotation shaft 2 and is spaced from the radial iron core 10 by a sixth preset distance to form a second axial working gap 19. This is a preferred structural form of the third annular portion and the fourth annular portion of the present invention, that is, the third annular portion extends axially and forms a first axial working gap with the bearing rotor, enabling a magnetic flux to pass between the third annular portion and the bearing rotor, and the third annular portion does not rotate with the bearing rotor. The fourth annular portion is spaced from the radial iron core by the second axial working gap, enabling a magnetic flux to pass between the fourth annular portion and the radial iron core, and the fourth annular portion does not form friction or magnetic leakage with the radial stator.

[0067] In some embodiments, the energization directions of the first axial winding 7 and the second axial winding 12 are opposite; the radial winding 5 is simultaneously located radially outside the second annular portion 6c and the fourth annular portion 11c, and both the second annular portion 6c and the fourth annular portion 11c are opposite to the radial stator pole column 8. The present invention also arranges the radial winding radially outside the first axial iron core and the second axial iron core, and both the second annular portion and the fourth annular portion are opposite to the radial stator pole column, so that compared with the existing solution where the upper magnetic pole of the axial stator is located beside the radial stator yoke (i.e., the upper magnetic pole of the existing axial stator is located on the axial side of the radial stator yoke), it can effectively reduce the magnetic leakage of the radial magnetic circuit in the axial direction and effectively prevent the unevenness of the axial output force in the circumferential direction.

[0068] The present invention also provides a motor, which includes the magnetic levitation active three-degree-of-freedom bearing described in any one of the previous items.

[0069] Advantages of the present invention:

[0070] 1. An 8-pole radial bearing is adopted, and the processing and manufacturing process is simple, and the radial magnetic circuit control is convenient. The axial stator magnetic poles adopt a segmented structure, which avoids the magnetic leakage phenomenon of the radial magnetic circuit on the outer circle of the axial stator and only enhances the air-gap magnetic field on the radial magnetic poles.

[0071] 2. There is no permanent magnet, the cost is low, the assembly is convenient, the bearing capacity is large, and it can operate at high power; the radial and axial integration is high, there is no thrust disk, the cost is reduced, the structure is compact, the process is simple, the critical speed is high, and the performance is stable.

[0072] The present invention also provides a compressor, which includes the magnetic levitation active three-degree-of-freedom bearing described in any one of the previous items.

[0073] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the technical principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A magnetic levitation active three-degree-of-freedom bearing, characterized in that: Comprising: An axial magnetic bearing (100), a radial magnetic bearing (200), and a bearing rotor (9). The axial magnetic bearing (100) and the radial magnetic bearing (200) are both sleeved on the outer periphery of a rotating shaft (2). The axial magnetic bearing (100) includes a first axial stator (300) and a second axial stator (400). The radial magnetic bearing (200) includes a radial stator (500). The radial stator (500) includes a radial iron core (10). The bearing rotor (9) is sleeved on the outer periphery of the rotating shaft (2) and can rotate together with the rotating shaft (2). The radial stator (500) is located on the outer periphery of the bearing rotor (9) and can apply a radial electromagnetic force to the bearing rotor (9). Along the axial direction of the rotating shaft (2), at least part of the structure of the first axial stator (300) is located at one axial end of the bearing rotor (9), and at least part of the structure of the second axial stator (400) is located at the other axial end of the bearing rotor (9). The first axial stator (300) and the second axial stator (400) can apply an axial electromagnetic force to the bearing rotor (9), so that the bias magnetic flux of the radial magnetic bearing (200) is provided by the axial magnetic bearing (100). The first axial stator (300) and the second axial stator (400) are both block structures arranged at intervals in the circumferential direction; The first axial stator (300) includes a first axial iron core (6) and a first axial winding (7). The first axial iron core (6) is of an annular structure. The first axial iron core (6) includes a first main body portion (6a), a first annular portion (6b), and a second annular portion (6c). The first main body portion (6a) is a disc structure having a first central hole. The first central hole accommodates the rotating shaft (2) to pass through. The second annular portion (6c) is located radially outside the first annular portion (6b). One end of the first annular portion (6b) is connected to the first main body portion (6a) and the other end extends towards the bearing rotor (9) to be opposite to the bearing rotor (9). One end of the second annular portion (6c) is connected to the first main body portion (6a) and the other end extends towards the radial iron core (10) to be opposite to the radial iron core (10), so as to form a first accommodation groove (6d) between the radially outer side of the first annular portion (6b) and the radially inner side of the second annular portion (6c). The first axial winding (7) is wound on the second annular portion (6c); The second axial stator (400) includes a second axial iron core (11) and a second axial winding (12). The second axial iron core (11) has an annular structure and includes a second main body portion (11a), a third annular portion (11b), and a fourth annular portion (11c). The second main body portion (11a) has a disc structure with a second central hole, and the second central hole accommodates the rotating shaft (2) passing therethrough. One end of the third annular portion (11b) is connected to the second main body portion (11a), and the other end extends towards the bearing rotor (9) to face the bearing rotor (9). One end of the fourth annular portion (11c) is connected to the second main body portion (11a), and the other end extends towards the radial iron core (10) to face the radial iron core (10). The fourth annular portion (11c) is located radially outside the third annular portion (11b) to form a second accommodation groove (11d) between the radially outer side of the third annular portion (11b) and the radially inner side of the fourth annular portion (11c). The second axial winding (12) is wound around the fourth annular portion (11c).

2. The magnetic levitation active three-degree-of-freedom bearing according to claim 1, wherein: The first axial stator (300) and the second axial stator (400) have the same structure and both include a first axial stator unit (61), a second axial stator unit (62), a third axial stator unit (63), and a fourth axial stator unit (64) that are sequentially arranged at intervals in the circumferential direction.

3. The magnetic levitation active three-degree-of-freedom bearing according to claim 2, wherein: The radial stator (500) further includes a radial winding (5). The radial iron core (10) has an annular structure and is sleeved on the radially outer side of the bearing rotor (9). The radial iron core (10) includes a radial stator yoke (1) and radial stator pole columns (8). The radial stator yoke (1) has an annular structure. The radially outer ends of the radial stator pole columns are connected to the radial stator yoke (1), and the radially inner ends protrude towards the bearing rotor (9) and have a radial working gap (15) with the bearing rotor (9). The radial winding (5) is wound around each radial stator pole column. And in the radial cross-section, the radial stator (500) includes a first quadrant portion in the upper right, a second quadrant portion in the upper left, a third quadrant portion in the lower left, and a fourth quadrant portion in the lower right. The first quadrant portion, the second quadrant portion, the third quadrant portion, and the fourth quadrant portion are sequentially connected counterclockwise. The first quadrant portion and the third quadrant portion form a diagonal, and the second quadrant portion and the fourth quadrant portion form a diagonal. The number of the radial stator pole columns is 4n, where n is a natural number.

4. The magnetic levitation active three-degree-of-freedom bearing according to claim 3, wherein: The radial stator pole column (8) includes a second radial magnetic pole (82) and a third radial magnetic pole (83) located in the first quadrant portion, a fourth radial magnetic pole (84) and a fifth radial magnetic pole (85) located in the fourth quadrant portion, a sixth radial magnetic pole (86) and a seventh radial magnetic pole (87) located in the third quadrant portion, and a first radial magnetic pole (81) and an eighth radial magnetic pole (88) located in the second quadrant portion.

5. The magnetic levitation active three-degree-of-freedom bearing according to claim 4, wherein: The magnetic paths inside the first radial magnetic pole (81), the bearing rotor (9), the second radial magnetic pole (82), and the radial stator yoke (1) are connected to form a closed loop, forming a radial bearing magnetic path (3); the magnetic paths inside the third radial magnetic pole (83), the bearing rotor (9), the fourth radial magnetic pole (84), and the radial stator yoke (1) are also connected to form a closed-loop radial bearing magnetic path (3); the magnetic paths inside the fifth radial magnetic pole (85), the bearing rotor (9), the sixth radial magnetic pole (86), and the radial stator yoke (1) are also connected to form a closed-loop radial bearing magnetic path (3); the magnetic paths inside the seventh radial magnetic pole (87), the bearing rotor (9), the eighth radial magnetic pole (88), and the radial stator yoke (1) are also connected to form a closed-loop radial bearing magnetic path (3).

6. The magnetic levitation active three-degree-of-freedom bearing according to claim 4, wherein: The first axial stator unit (61) faces the first radial magnetic pole (81) and the eighth radial magnetic pole (88) in the second quadrant portion, and provides a bias magnetic path to the first radial magnetic pole (81) and the eighth radial magnetic pole (88) through the first axial stator unit (61); the second axial stator unit (62) faces the second radial magnetic pole (82) and the third radial magnetic pole (83) in the first quadrant portion, and provides a bias magnetic path to the second radial magnetic pole (82) and the third radial magnetic pole (83) through the second axial stator unit (62); the third axial stator unit (63) faces the fourth radial magnetic pole (84) and the fifth radial magnetic pole (85) in the fourth quadrant portion, and provides a bias magnetic path to the fourth radial magnetic pole (84) and the fifth radial magnetic pole (85) through the third axial stator unit (63); the fourth axial stator unit (64) faces the sixth radial magnetic pole (86) and the seventh radial magnetic pole (87) in the third quadrant portion, and provides a bias magnetic path to the sixth radial magnetic pole (86) and the seventh radial magnetic pole (87) through the fourth axial stator unit (64).

7. The magnetic levitation active three-degree-of-freedom bearing according to claim 6, wherein: The bias magnetic paths provided by the first axial stator unit (61) for the first radial magnetic pole (81) and the eighth radial magnetic pole (88) both extend in the radial direction towards the center of the rotating shaft (2); the bias magnetic paths provided by the second axial stator unit (62) for the second radial magnetic pole (82) and the third radial magnetic pole (83) both extend in the radial direction away from the center of the rotating shaft (2); the bias magnetic paths provided by the third axial stator unit (63) for the fourth radial magnetic pole (84) and the fifth radial magnetic pole (85) both extend in the radial direction towards the center of the rotating shaft (2); the bias magnetic paths provided by the fourth axial stator unit (64) for the sixth radial magnetic pole (86) and the seventh radial magnetic pole (87) both extend in the radial direction away from the center of the rotating shaft (2).

8. The magnetic levitation active three-degree-of-freedom bearing according to claim 1, wherein: The first annular portion (6b) extends along the axial direction of the rotating shaft (2) and is spaced from the bearing rotor (9) by a third preset distance to form a first axial working gap (16); the second annular portion (6c) also extends along the axial direction of the rotating shaft (2) and is spaced from the radial iron core (10) by a fourth preset distance to form a second axial working gap (19).

9. The magnetic levitation active three-degree-of-freedom bearing according to claim 1, wherein: The third annular portion (11b) extends along the axial direction of the rotating shaft (2) and is spaced from the bearing rotor (9) by a fifth preset distance to form a first axial working gap (16); the fourth annular portion (11c) also extends along the axial direction of the rotating shaft (2) and is spaced from the radial iron core (10) by a sixth preset distance to form a second axial working gap (19).

10. The magnetic levitation active three-degree-of-freedom bearing according to claim 3, wherein: The energization directions of the first axial winding (7) and the second axial winding (12) are opposite; the radial winding (5) is simultaneously located radially outside the second annular portion (6c) and the fourth annular portion (11c), and both the second annular portion (6c) and the fourth annular portion (11c) are opposite to the radial stator pole posts (8).

11. A motor, characterized in that: Comprising the magnetic levitation active three-degree-of-freedom bearing according to any one of claims 1-10.

12. A compressor, characterized in that: Comprising the magnetic levitation active three-degree-of-freedom bearing according to any one of claims 1-10.

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