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

Abstract

The application provides a magnetic suspension active three-degree-of-freedom bearing, motor and compressor, which comprises an axial magnetic bearing, a radial magnetic bearing and a bearing rotor, the axial magnetic bearing comprises a first axial stator and a second axial stator, the radial magnetic bearing comprises a radial stator, the radial stator is located at the outer periphery of the bearing rotor and can exert a radial electromagnetic force on the bearing rotor, the first axial stator and the second axial stator can exert an axial electromagnetic force on the bearing rotor, and at least part of the structure of the first axial stator and the second axial stator is located radially outside the radial winding, the part of the structure of the first axial stator and the second axial stator is connected with the radially outer end of the radial core, so that the bias magnetic flux of the radial magnetic bearing is provided by the axial magnetic bearing. According to the application, the first axial stator and the second axial stator can effectively provide a bias magnetic circuit for the radial stator, the original structure such as a bias stator is omitted, 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 application relates to the technical field of magnetic suspension, in particular to a magnetic suspension active three-degree-of-freedom bearing, motor and compressor. BACKGROUND

[0002] The magnetic suspension bearing suspends the rotating shaft by electromagnetic force on the rotor, and the rotating shaft and the stator are in a non-contact state, so it has the advantages of no wear, high speed, high precision and long service life. Magnetic bearings can be divided into three categories according to working principle: active magnetic bearing, passive magnetic bearing and hybrid magnetic bearing.

[0003] The active three-degree-of-freedom magnetic bearing structure in patent number CN110017330A "Axial and radial electromagnetic type magnetic bearing" is complex, which adopts an E-shaped salient radial block stator to form a bias magnetic flux for the radial bearing. Its processing and manufacturing process is complex, difficult to assemble, and there is a radial suspension winding leakage in the axial direction.

[0004] Because the magnetic suspension active three-degree-of-freedom bearing in the prior art forms a bias magnetic flux for the radial bearing by setting a bias stator, resulting in a complex structure, large volume, complex process, difficult assembly and other technical problems, therefore the present application researches and designs a magnetic suspension active three-degree-of-freedom bearing, motor and compressor. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to overcome the defects of the magnetic suspension active three-degree-of-freedom bearing in the prior art, which forms a bias magnetic flux for the radial bearing by setting a bias stator, resulting in a complex structure and large volume, thereby providing a magnetic suspension active three-degree-of-freedom bearing, motor and compressor.

[0006] In order to solve the above problems, the present application provides a magnetic suspension active three-degree-of-freedom bearing, which comprises:

[0007] An axial magnetic bearing and a radial magnetic bearing are sleeved on the outer periphery of a rotating shaft, the axial magnetic bearing comprises a first axial stator and a second axial stator, the radial magnetic bearing comprises a radial stator, a bearing rotor is sleeved on the outer periphery of the rotating shaft and can rotate with the rotating shaft, the radial stator is located on the outer periphery of the bearing rotor and can exert a radial electromagnetic force on the bearing rotor, at least part of the structure of the first axial stator is located at one axial end of the bearing rotor in the axial direction of the rotating shaft, at least part of the structure of the second axial stator is located at the other axial end of the bearing rotor, and the first axial stator and the second axial stator can exert an axial electromagnetic force on the bearing rotor; the radial stator comprises a radial core and a radial winding, the radial core is annular in structure and is sleeved on the radial outer side of the bearing rotor; at least part of the structure of the first axial stator is located on the radial outer side of the radial winding, at least part of the structure of the first axial stator is connected with the radial outer end of the radial core, at least part of the structure of the second axial stator is located on the radial outer side of the radial winding, and at least part of the structure of the second axial stator is connected with the radial outer end of the radial core, so that the bias magnetic flux of the radial magnetic bearing is provided by the axial magnetic bearing.

[0008] In some embodiments, in the axial direction, the axial length of the radial core is smaller than the axial length of the bearing rotor, the first axial end of the bearing rotor opposite to the first axial stator protrudes from the third axial end of the radial core opposite to the first axial stator by a first predetermined distance, so that the third axial end of the radial core is retracted relative to the first axial end to form a first space, and at least part of the structure of the first axial stator extends to connect with the radial outer end of the radial core.

[0009] The second axial end of the bearing rotor opposite to the second axial stator protrudes from the fourth axial end of the radial core opposite to the second axial stator by a second predetermined distance, so that the fourth axial end of the radial core is retracted relative to the second axial end to form a second space, and at least part of the structure of the second axial stator extends to connect with the radial outer end of the radial core.

[0010] In some embodiments, the first axial stator comprises a first axial core and a first axial winding, the first axial core is annular structure, the first axial core comprises a first main body part, a first annular part and a second annular part, the first main body part is disc structure with a first central hole, the first central hole accommodates the rotating shaft therethrough, the second annular part is located radially outward of the first annular part, one end of the first annular part is connected with the first main body part and the other end extends to the opposite side of the bearing rotor, one end of the second annular part is connected with the first main body part and the other end extends to the radial outer end of the radial core, so as to form a first accommodating groove between the radially outer side of the first annular part and the radially inner side of the second annular part, the first axial winding is arranged in the first accommodating groove and wound on the inner periphery of the second annular part.

[0011] In some embodiments, the first annular part extends along the axial direction of the rotating shaft and is spaced apart from the bearing rotor by a third predetermined distance to form an axial working gap; the second annular part also extends along the axial direction of the rotating shaft.

[0012] The axial length of the second annular part is greater than the axial length of the first annular part, and one end of the second annular part opposite to the first main body part is located radially outward of the radial core.

[0013] In some embodiments, the second axial stator comprises a second axial core and a second axial winding, the second axial core is annular structure, the second axial core comprises a second main body part, a third annular part and a fourth annular part, the second main body part is disc structure with a second central hole, the second central hole accommodates the rotating shaft therethrough, and the fourth annular part is located radially outward of the third annular part, one end of the third annular part is connected with the second main body part and the other end extends to the opposite side of the bearing rotor, one end of the fourth annular part is connected with the second main body part and the other end extends to the radial outer end of the radial core, so as to form a second accommodating groove between the radially outer side of the third annular part and the radially inner side of the fourth annular part, the second axial winding is arranged in the second accommodating groove and wound on the inner periphery of the fourth annular part.

[0014] In some embodiments, the third annular part extends along the axial direction of the rotating shaft and is spaced apart from the bearing rotor by a fifth predetermined distance to form an axial working gap; the fourth annular part also extends along the axial direction of the rotating shaft.

[0015] The fourth annular portion has an axial length greater than that of the third annular portion, and an end of the fourth annular portion opposite to the second main portion is located radially outside the radial core, and the fourth annular portion is connected to the second annular portion or is spaced apart from the second annular portion.

[0016] In some embodiments, the first axial winding and the second axial winding have opposite energization directions.

[0017] In some embodiments, the radial core includes a radial stator yoke and radial stator poles, the radial stator yoke is an annular structure, the radial stator poles have radial outer ends connected to the radial stator yoke and radial inner ends protruding towards the bearing rotor with a radial working gap therebetween, and the radial stator poles are each provided with the radial winding therearound.

[0018] In a radial cross section, the radial stator includes a first quadrant portion located at the upper right, a second quadrant portion located at the upper left, a third quadrant portion located at the lower left, and a fourth quadrant portion located at the lower right, the first, second, third, and fourth quadrant portions are sequentially connected in counterclockwise order, the first and third quadrant portions form opposite angles, the second and fourth quadrant portions form opposite angles, and the magnetic circuit formed by the radial stator poles and yoke portions in the second quadrant portion is in communication with the magnetic circuit formed by the radial stator poles and yoke portions in the fourth quadrant portion, forming a left radial control magnetic circuit, and the magnetic circuit formed by the radial stator poles and yoke portions in the first quadrant portion is in communication with the magnetic circuit formed by the radial stator poles and yoke portions in the third quadrant portion, forming a right radial control magnetic circuit.

[0019] In some embodiments, the number of radial stator poles is 4n, where n is a natural number.

[0020] In some embodiments, in each quadrant portion, two radial stator poles are provided, and the radial stator poles located in the second and fourth quadrant portions are the upper left radial stator poles and the lower right radial stator poles, respectively.

[0021] In some embodiments, the axial magnetic bearing provides an axial bias magnetic circuit for the radial magnetic bearing, and the bias magnetic flux provided by the axial magnetic bearing is in the radial direction towards the center of the rotating shaft; or the axial magnetic bearing provides an axial bias magnetic circuit for the radial magnetic bearing, and the bias magnetic flux provided by the axial magnetic bearing is in the radial direction away from the center of the rotating shaft; in the two opposite angle quadrant portions, the magnetic flux in one of the quadrant portions is in the radial direction towards the center of the rotating shaft, and the magnetic flux in the other of the quadrant portions is in the radial direction away from the center of the rotating shaft.

[0022] In some embodiments, when the first axial stator comprises a first axial core and a first axial winding, the first axial core comprises a first main body part, a first annular part and a second annular part, the second axial stator comprises a second axial core and a second axial winding, the second axial core comprises a second main body part, a third annular part and a fourth annular part, and the radial winding is located radially inside the second annular part and the fourth annular part, and the second annular part and the fourth annular part are located radially outside the radial stator yoke.

[0023] In some embodiments, when the first axial stator comprises a first axial core and a first axial winding, the first axial core comprises a first main body part, a first annular part and a second annular part, the second axial stator comprises a second axial core and a second axial winding, the second axial core comprises a second main body part, a third annular part and a fourth annular part, and the radial winding is located radially inside the second annular part and the fourth annular part, and the second annular part and the fourth annular part are located radially outside the radial stator yoke.

[0024] The application further provides an electric machine comprising the magnetic levitation active three-degree-of-freedom bearing according to any one of the preceding items.

[0025] The application further provides a compressor comprising the magnetic levitation active three-degree-of-freedom bearing according to any one of the preceding items.

[0026] The magnetic levitation active three-degree-of-freedom bearing, the electric machine and the compressor provided by the application have the following beneficial effects:

[0027] 1. The present application is characterized in that the axial magnetic bearing and the radial magnetic bearing are effectively arranged, the radial stator is located at the outer periphery of the bearing rotor and can exert radial electromagnetic force on the bearing rotor, at least part of the structure of the first axial stator is located at one axial end of the bearing rotor, 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 exerted on the bearing rotor by the first axial stator and the second axial stator, so that the bearing rotor can be adjusted in radial offset by the radial electromagnetic force exerted by the radial stator, and the bearing rotor can be adjusted in axial offset by the axial electromagnetic force exerted by the first and second axial stators, so as to achieve the purpose of radial and axial support of the rotating shaft, and at least part of the structure of the first axial stator is located radially outside the radial stator, and at least part of the structure of the second axial stator is located radially outside the radial stator, so that the bias magnetic flux of the radial magnetic bearing is provided by the axial magnetic bearing, so that compared with the existing active three-degree-of-freedom magnetic suspension bearing, the bias magnetic circuit of the radial bearing is provided by setting structures such as bias stators, the first and second axial stators can effectively provide the bias magnetic circuit for the radial stator by setting the above structure, the original structures such as bias stators are omitted, the structure is more compact and simple, the process difficulty is reduced, the volume is reduced, and the assembly is easy; the radial magnetic bearing and the axial magnetic bearing are effectively combined together to form an integrated shaft and radial magnetic bearing structure, compared with the separate axial magnetic bearing and radial magnetic bearing in the prior art, the structure of the thrust bearing for the axial magnetic bearing is effectively omitted, so that the axial size 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 rotor critical speed is improved, and the stability and applicability of the magnetic suspension system are improved; the axial stator provides the bias magnetic circuit for the radial stator, which can effectively omit the structure of the permanent magnet compared with the hybrid magnetic suspension bearing, has low cost, convenient assembly, large bearing capacity, and can operate at high power;

[0028] 2. The present application can greatly shorten the outer diameter of the radial stator and the thickness of the axial stator and reduce the volume of the bearing stator under the same radial and axial output, compared with the prior art in which the upper magnetic pole of the axial stator is located beside the magnetic yoke of the radial stator (i.e. the upper magnetic pole of the axial stator is located on the axial side of the magnetic yoke of the radial stator), and the second annular part and the fourth annular part are located outside the radial core. The present application can provide two power amplifiers through the diagonal communication of the radial magnetic circuit, and can effectively reduce the material cost and the current loss, compared with the prior art in which four power amplifiers are used. The magnetic circuit has a wide range of control over the radial direction of the rotating shaft, has good control effect, high precision, and simple control method. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a longitudinal sectional view of the magnetic suspension active three-degree-of-freedom bearing of the present application (axial section, axial magnetic circuit of the three-degree-of-freedom bearing);

[0030] Figure 2 is Figure 1 is a cooperation structure diagram of the axial stator, the radial stator and the bearing rotor in the upper half of

[0031] Figure 3 is a longitudinal sectional view of the magnetic suspension active three-degree-of-freedom bearing of the present application (axial section, axial magnetic circuit of the three-degree-of-freedom bearing).

[0032] The reference signs are as follows:

[0033] 100, axial magnetic bearing; 300, first axial stator; 1, first axial core; 1a, first main body part; 1b, first annular part; 1c, second annular part; 1d, first accommodating groove; 3, first axial winding; 400, second axial stator; 2, second axial core; 2a, second main body part; 2b, third annular part; 2c, fourth annular part; 2d, second accommodating groove; 4, second axial winding; 200, radial magnetic bearing; 500, radial stator; 5, radial winding; 6, radial core; 61, third axial end; 62, fourth axial end; 7, bearing rotor; 71, first axial end; 72, second axial end; 8, rotating shaft; 9, left axial upper magnetic pole; 10, right axial upper magnetic pole; 11, radial stator magnetic yoke; 12, radial stator pole column; 13, left axial lower magnetic pole; 14, right axial lower magnetic pole; 15, radial working gap; 16, axial working gap; 001, axial bias magnetic circuit; 002, left radial control magnetic circuit; 003, right radial control magnetic circuit; 17, left upper radial stator pole column; 18, right lower radial stator pole column. DETAILED DESCRIPTION

[0034] As Figures 1-3As shown, the application provides a magnetic suspension active three-degree-of-freedom bearing, which comprises:

[0035] The axial magnetic bearing 100 and the radial magnetic bearing 200 are sleeved on the outer periphery of the rotating shaft 8, the axial magnetic bearing 100 comprises a first axial stator 300 and a second axial stator 400, the radial magnetic bearing 200 comprises a radial stator 500, the bearing rotor 7 is sleeved on the outer periphery of the rotating shaft 8 and can rotate with the rotating shaft 8, the radial stator 500 is located on the outer periphery of the bearing rotor 7 and can exert a radial electromagnetic force on the bearing rotor 7, at least part of the structure of the first axial stator 300 is located at one axial end of the bearing rotor 7 in the axial direction of the rotating shaft 8, at least part of the structure of the second axial stator 400 is located at the other axial end of the bearing rotor 7, the first axial stator 300 and the second axial stator 400 can exert an axial electromagnetic force on the bearing rotor 7, the radial stator 500 comprises a radial core 6 and a radial winding 5, the radial core 6 is annular in structure and is sleeved on the radial outer side of the bearing rotor 7, at least part of the structure of the first axial stator 300 is located on the radial outer side of the radial winding 5 (i.e. also on the radial outer side of the bearing rotor), at least part of the structure of the first axial stator 300 is connected with the radial outer end of the radial core, at least part of the structure of the second axial stator 400 is located on the radial outer side of the radial winding 5 (i.e. also on the radial outer side of the bearing rotor), at least part of the structure of the second axial stator 400 is connected with the radial outer end of the radial core, so that the bias magnetic flux of the radial magnetic bearing 200 is provided by the axial magnetic bearing 100.

[0036] The axial magnetic bearing and the radial magnetic bearing are effectively arranged, the radial stator is located at the outer periphery of the bearing rotor and can exert radial electromagnetic force on the bearing rotor, at least part of the structure of the first axial stator is located at one axial end of the bearing rotor, 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 exerted on the bearing rotor by the first axial stator and the second axial stator, so that the bearing rotor can be adjusted in radial deviation of the rotating shaft by the radial electromagnetic force exerted by the radial stator, and the bearing rotor can be adjusted in axial deviation of the rotating shaft by the axial electromagnetic force exerted by the first and second axial stators, finally achieving the purpose of radial and axial support of the rotating shaft, and at least part of the structure of the first axial stator is located radially outside the radial stator, at least part of the structure of the second axial stator is located radially outside the radial stator, so that the bias magnetic flux of the radial magnetic bearing is provided by the axial magnetic bearing, compared with the prior art active three-degree-of-freedom magnetic suspension bearing which needs to provide a bias magnetic circuit for the radial bearing by setting structures such as a bias stator, the first and second axial stators can effectively provide a bias magnetic circuit for the radial stator by setting the above structure, the original structure such as the bias stator is omitted, the structure is more compact and simple, the process difficulty is reduced, the volume is reduced, and the assembly is easy; the radial magnetic bearing and the axial magnetic bearing are effectively combined together to form an integrated shaft and a radial integrated magnetic bearing structure, compared with the prior art separate axial magnetic bearing and radial magnetic bearing which needs to separately set a thrust bearing for the axial magnetic bearing to provide axial force for the rotating shaft, and needs to set a radial magnetic bearing rotor for the radial magnetic bearing, the structure of the thrust bearing is effectively omitted, 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 improved, and the stability and applicability of the magnetic suspension system are improved; the axial stator provides a bias magnetic circuit for the radial stator, the structure of the permanent magnet can be effectively omitted compared with the hybrid magnetic suspension bearing, the cost is low, the assembly is convenient, the bearing capacity is large, and high-power operation is possible.

[0037] The active three-degree-of-freedom magnetic bearing provided by the application adopts a single-coil mode for an axial winding, is installed in left and right axial stators, is located at both ends of a radial stator yoke (or is fixed on the radial stator yoke), saves space, provides an axial magnetic circuit, controls axial movement of a bearing rotor, has 4n magnetic poles (n is 1, 2, 3, 4, …), the upper end magnetic pole of the radial stator is an N pole, the upper end magnetic pole of the radial stator is an S pole (or the upper end is an S pole and the lower end is an N pole), the axial magnetic circuit strengthens or weakens a radial air gap magnetic field in the radial direction, controls movement of the rotor in the radial direction, simultaneously realizes movement of the rotor in three degrees of freedom in the radial and axial directions, effectively reduces the size of the bearing stator, shortens the length of the rotor, and improves the stability of the rotor in operation under the condition of equal radial and axial output.

[0038] The application effectively removes the thrust disc, replaces it with a bearing rotor, and integrates the radial bearing and the axial bearing. Compared with the conventional active magnetic bearing, the application does not need to install a thrust disc, has a compact structure, and is simple in process; compared with the conventional hybrid three-degree-of-freedom magnetic bearing, the application does not have a permanent magnet, provides a bias magnetic field and a control magnetic field by electromagnetic force, has large carrying capacity, high stiffness, and flexible control, can operate at high power and high critical speed, and improves the stability and applicability of the magnetic suspension system.

[0039] The technical problem solved by the application is:

[0040] 1. The application integrates the radial bearing and the axial bearing, does not have a thrust disc, has a compact structure, reduces the size of the bearing, shortens the length of the rotor, improves the critical speed of the rotor, and improves the stability and applicability of the magnetic suspension system.

[0041] 2. Compared with the magnetic pole in the axial direction being located beside the radial stator yoke, the application can greatly shorten the outer diameter of the radial stator and the thickness of the axial stator under the condition of equal radial and axial output, and reduce the size of the bearing stator.

[0042] Advantages of the application:

[0043] 1. The radial and axial bearing stator of the application is simple in processing and manufacturing process, and convenient in axial magnetic circuit control.

[0044] 2. The application is integrated in the radial and axial directions, does not have a thrust disc, reduces cost, has a compact structure, is simple in process, has high critical speed, and is stable in performance; the application does not have a permanent magnet, is low in cost, is convenient to assemble, has large carrying capacity, and can operate at high power.

[0045] In some embodiments, in the axial direction, the axial length of the radial core 6 is less than the axial length of the bearing rotor 7, the first axial end 71 of the bearing rotor 7 opposite to the first axial stator 300 protrudes a first preset distance than the third axial end 61 of the radial core 6 opposite to the first axial stator 300, so that the third axial end 61 of the radial core 6 is retracted relative to the first axial end 71 to form a first space, and at least part of the structure of the first axial stator 300 extends to the radial outer end of the radial core 6;

[0046] The second axial end 72 of the bearing rotor 7 opposite to the second axial stator 400 protrudes a second preset distance than the fourth axial end 62 of the radial core 6 opposite to the second axial stator 400, so that the fourth axial end 62 of the radial core 6 is retracted relative to the second axial end 72 to form a second space, and at least part of the structure of the second axial stator 400 extends to the radial outer end of the radial core 6.

[0047] The axial length of the radial core is less than the axial length of the bearing rotor, and the magnetic flux leakage of the axial stator is placed in the retracted space, which effectively ensures that the magnetic flux of the two axial stators can enter the radial stator, thereby providing bias magnetic flux for the radial stator without adding bias stators, permanent magnets and other structures, and the structure is more compact, the volume is reduced, and a integrated active three-degree-of-freedom magnetic suspension bearing is formed.

[0048] This is the preferred cooperation structure form between the radial core, the first axial stator and the second axial stator of the present application, that is, the first space formed by the inward retraction of the third axial end of the radial core relative to the first axial end of the bearing rotor by a first preset distance can prevent the magnetic flux of the axial stator from leaking from the radial stator part at the first space position if the first space is not provided, at least part of the structure of the first axial stator extends to the outer end of the radial stator, so that the magnetic flux generated by the first axial stator can enter the radial stator and then enter the bearing rotor, thereby providing bias magnetic circuit for the radial stator without adding bias stators, permanent magnets and other structures, and the structure is more compact and the volume is reduced; the second space formed by the inward retraction of the fourth axial end of the radial core relative to the second axial end of the bearing rotor by a second preset distance can prevent the magnetic flux of the axial stator from leaking from the radial stator part at the first space position if the first space is not provided, at least part of the structure of the second axial stator extends to the outer end of the radial stator, so that the magnetic flux generated by the second axial stator can enter the radial stator and then enter the bearing rotor, thereby providing bias magnetic circuit for the radial stator without adding bias stators, permanent magnets and other structures, and the structure is more compact and the volume is reduced.

[0049] In some embodiments, the first axial stator 300 comprises a first axial core 1 and a first axial winding 3, the first axial core 1 is annular structure, the first axial core 1 comprises a first main body part 1a, a first annular part 1b (i.e. left axial lower magnetic pole 13 in Figure 1 Figure 1 the first annular part 1b is annular structure, the first annular part 1b comprises a first annular hole, the first annular hole is arranged to accommodate the bearing rotor 7 to pass through, the first annular part 1b is arranged to be opposite to the bearing rotor 7, the first annular part 1b is arranged to be opposite to the first main body part 1a (preferably the radial inner end) and the other end extends to the radial outer end of the radial core 6, so as to form a first accommodating slot 1d between the radial outer side of the first annular part 1b and the radial inner side of the second annular part 1c, the first axial winding 3 is arranged in the first accommodating slot 1d and wound on the inner periphery of the second annular part 1c.

[0050] This is the preferred structure of the first axial stator of the present application, the first accommodating slot for accommodating the first axial winding is formed by the first annular part and the second annular part, and the first annular part is opposite to the bearing rotor to accommodate the magnetic circuit to pass through, and the second annular part extends to the radial outer end of the radial stator and is connected with the radial stator, which can effectively improve the radial core and the second annular part, so that the second annular part, the radial core, the bearing rotor, the first annular part and the first main body part form a closed magnetic circuit, and such structure can provide radial bias magnetic flux for the radial stator, so that the first axial stator and the radial stator are integrated into a structure, effectively saving the structure of thrust disc, permanent magnet, bias stator and the like, and the structure is compact and the volume is effectively reduced.

[0051] In some embodiments, the first annular part 1b extends along the axial direction of the rotating shaft 8 and is spaced apart from the bearing rotor 7 by a third predetermined distance to form an axial working gap 16; the second annular part 1c also extends along the axial direction of the rotating shaft 8;

[0052] The axial length of the second annular part 1c is greater than the axial length of the first annular part 1b, and the end of the second annular part 1c opposite to the first main body part 1a is located on the radial outer side of the radial core 6.

[0053] ​This is a preferred structural form of the first and second annular portions of the present invention. The first annular portion extends axially and forms an axial working gap with the bearing rotor, allowing magnetic flux to pass between the first annular portion and the bearing rotor. The first annular portion does not rotate with the bearing rotor. The second annular portion is connected to the outer end of the radial iron core, allowing magnetic flux to pass between the second annular portion and the radial iron core. The axial length of the second annular portion is greater than that of the first annular portion, so that the second annular portion in the radial direction is partially opposite to the bearing rotor. This allows the magnetic circuit in the first axial stator to be transmitted to the radial iron core and the bearing rotor, forming a more compact integrated bearing stator and radial stator structure. This eliminates the need for thrust disks, offset stators, permanent magnets, and other structures, reducing the volume.

[0054] In some embodiments, the second axial stator 400 includes a second axial core 2 and a second axial winding 4. The second axial core 2 is an annular structure, comprising a second main body 2a, a third annular portion 2b, and a fourth annular portion 2c. The second main body 2a is a disc structure with a second central hole, through which the rotating shaft 8 passes. The fourth annular portion 2c is located radially outside the third annular portion 2b. One end of the third annular portion 2b is connected to the second main body 2a (preferably radially inner end), and the other end extends toward the bearing rotor 7 to be opposite to the bearing rotor 7. One end of the fourth annular portion 2c is connected to the second main body 2a (preferably radially outer end), and the other end extends to the radially outer end of the radial core 6 to form a second receiving groove 2d between the radially outer side of the third annular portion 2b and the radially inner side of the fourth annular portion 2c. The second axial winding 4 is disposed in the second receiving groove 2d and wound around the inner circumference of the fourth annular portion 2c.

[0055] This is a preferred structural form of the second axial stator of the present invention. The third and fourth annular portions can form a second receiving groove to accommodate the second axial winding. The third annular portion is opposite to the bearing rotor to accommodate the magnetic circuit. The fourth annular portion extends to the outer end of the radial stator and connects with the radial stator. This can effectively improve the radial core and the fourth annular portion, so that the fourth annular portion, the radial core, the bearing rotor, the third annular portion and the second main body form a closed magnetic path. This structure can enable the second axial stator to provide radial bias magnetic flux to the radial stator, so that the second axial stator and the radial stator are integrated into a single structure. This effectively eliminates the need for thrust disk, permanent magnet, bias stator and other structures, resulting in a compact structure and a significant reduction in volume.

[0056] In some embodiments, the third annular portion 2b extends along the axial direction of the rotating shaft 8 and is spaced apart from the bearing rotor 7 by a fifth preset distance to form an axial working gap 16; the fourth annular portion 2c also extends along the axial direction of the rotating shaft 8.

[0057] The axial length of the fourth annular portion 2c is greater than the axial length of the third annular portion 2b, and the end of the fourth annular portion 2c opposite to the second main portion 2a is located radially outside the radial core 6.

[0058] This is the preferred structure of the third annular portion and the fourth annular portion of the application, that is, the third annular portion extends along the axial direction and forms an axial working gap between the third annular portion and the bearing rotor, so that the magnetic flux can pass between the third annular portion and the bearing rotor, and the third annular portion does not rotate with the bearing rotor, and the fourth annular portion is connected to the outer end of the radial core, so that the magnetic flux can pass between the fourth annular portion and the radial core; the axial length of the fourth annular portion is greater than the axial length of the third annular portion, so that the part of the fourth annular portion in the radial direction is opposite to the part of the bearing rotor, and the magnetic circuit in the second axial stator can be transmitted to the radial core and the bearing rotor, forming a structure of the integrated bearing stator and the radial stator with more compact structure, and the structures such as the thrust disc, the biasing stator and the permanent magnet are omitted, and the volume is reduced.

[0059] In some embodiments, the energization directions of the first axial winding 3 and the second axial winding 4 are opposite. The opposite energization directions of the two axial windings can make the biasing magnetic flux generated by the two axial stators on the radial stator all point to the radial inner side, so that a larger biasing magnetic circuit can be provided for the radial core, and thus the radial magnetic flux of the radial winding can be reduced, the power of the radial winding can be reduced, and the utilization rate of the axial magnetic bearing can be improved; the radial winding wound along the axial direction can generate magnetic flux along the radial direction, which can point to the radial inner side or the radial outer side, thereby providing a control magnetic flux path for the radial output of the magnetic levitation bearing.

[0060] The active three-degree-of-freedom magnetic bearing structure of the application is shown in Figure 1 Compared with the conventional active magnetic bearing structure, the thrust disc is removed and replaced by the bearing rotor, the axial stators are located at the two ends of the radial stator, and the radial bearing and the axial bearing are integrated. The structure mainly comprises the left axial stator (including the first axial core 1 and the first axial winding 3), the right axial stator (including the second axial core 2 and the second axial winding 4), the radial winding 5, the radial stator (including the radial core 6 and the radial winding 5), the bearing rotor 7, the rotating shaft 8 and other parts.

[0061] Figure 1The axial magnetic circuit of the active three-degree-of-freedom axial bearing is shown. The axial stator structure is as shown in the figure. The upper magnetic poles of the axial stator are located in the radial stator yoke 11, and the lower magnetic poles of the axial stator are located at both ends of the bearing rotor 7. The axial bias magnetic circuit 001 generated by the axial winding includes a left axial magnetic circuit and a right axial magnetic circuit, which are used to control the axial movement of the bearing rotor. The left axial magnetic circuit passes through the left axial upper magnetic pole 9-radial stator yoke 11-radial stator pole column 12-radial working gap 15-bearing rotor 7-axial working gap 16-left axial lower magnetic pole 13 back to the left axial stator (i.e. the first main body part 1a) to close. The right axial magnetic circuit passes through the right axial upper magnetic pole 10-radial stator yoke 11-radial stator pole column 12-radial working gap 15-bearing rotor 7-axial working gap 16-right axial lower magnetic pole 14 back to the right axial stator (i.e. the second main body part 2a) to close. When the bearing rotor needs to move to the left, the current of the left axial winding is increased, and the bearing rotor receives a larger force to the left. Conversely, when the bearing rotor needs to move to the right, the current of the right axial winding is increased, and the bearing rotor receives a larger force to the right. Thus, by controlling the current of the left and right axial windings, the axial movement of the bearing rotor can be controlled.

[0062] In some embodiments, the radial core 6 includes a radial stator yoke 11 and a radial stator pole column 12. The radial stator yoke 11 is in the form of a ring structure. The radial outer end of the radial stator pole column is connected to the radial stator yoke 11, and the radial inner end protrudes towards the bearing rotor 7 and has a radial working gap 15 with the bearing rotor 7. The radial winding 5 is wound around each radial stator pole column.

[0063] 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, second, third, and fourth quadrant portions are sequentially connected in counterclockwise direction. The first and third quadrant portions form a diagonal, and the second and fourth quadrant portions form a diagonal. The magnetic circuit formed by the radial stator pole column and the yoke portion in the second quadrant portion is in communication with the magnetic circuit formed by the radial stator pole column and the yoke portion in the fourth quadrant portion, forming a left radial control magnetic circuit 002. The magnetic circuit formed by the radial stator pole column and the yoke portion in the first quadrant portion is in communication with the magnetic circuit formed by the radial stator pole column and the yoke portion in the third quadrant portion, forming a right radial control magnetic circuit 003.

[0064] The application can provide 2-way power amplifier by the radial magnetic circuit pair diagonal communication setting form, compared with the existing 4-way power amplifier structure, the application can effectively reduce material cost, and reduce current loss, and the above-mentioned magnetic circuit control radial direction moving position of the rotating shaft is wide, the control effect is good, the precision is high, and the control method is simple.

[0065] Figure 3 As shown in the figure, it is a radial magnetic circuit of the active three-degree-of-freedom radial bearing of the application, the radial stator structure is as shown in the figure, there are 4n magnetic poles (n is 1, 2, 3, 4, …), the upper end magnetic pole of the radial stator is N pole, and the lower end magnetic pole of the radial stator is S pole (or the upper end is S pole, and the lower end is N pole), and the radial magnetic circuit is as shown in the figure. Figure 3 The upper left coil of the radial stator is connected in series with the lower right coil, to generate left radial control magnetic circuit 002, and the upper right coil of the radial stator is connected in series with the lower left coil, to generate right radial control magnetic circuit 003, for example, if the bearing rotor moves to the left upper direction, the coil is connected with positive current, the left radial control magnetic circuit 002 is closed through the left upper radial stator pole column 17-radial working gap 15-bearing rotor 7-radial working gap 15-right lower radial stator pole column 18-radial stator yoke 11-back to the left upper radial stator pole column 17, and the axial bias magnetic circuit 001 provided by the axial direction is as shown by the dotted line, all pointing to the center of the circle (or pointing to the circumference), the magnetic field of the left upper magnetic pole of the radial stator is enhanced, the magnetic field of the right lower magnetic pole is weakened, so that the bearing rotor is subjected to force to the left upper direction, and the same is true if the bearing rotor moves to the right upper direction, the magnetic field of the right upper magnetic pole of the radial stator is enhanced, and the magnetic field of the left lower magnetic pole is weakened. Figure 3 The radial direction movement of the bearing rotor is controlled by adjusting the size and polarity of the radial current, to realize radial stable suspension, the above-mentioned magnetic circuit controls the radial direction movement of the rotating shaft, and the control method is simple. The three-degree-of-freedom magnetic bearing structure integrates the radial bearing and the axial bearing, without thrust disc, compact structure, simple process, effectively reduces the bearing volume under the condition of the same output, improves the rotor critical speed, and improves the system running stability.

[0066] In some embodiments, 2 radial stator pole columns 12 are arranged in each quadrant part, and the radial stator pole column located in the second quadrant part is the left upper radial stator pole column 17, and the radial stator pole column located in the fourth quadrant part is the right lower radial stator pole column 18. The number of radial stator pole columns is 4n, wherein n is a natural number. The circumferential widths of the plurality of radial stator pole columns are preferably equal, so that the magnetic flux passing through is the same.

[0067] In some embodiments, the axial magnetic bearing 100 forms an axial bias magnetic circuit 001 with the bias magnetic flux provided by the radial magnetic bearing 200 in a radial direction towards the center of the rotating shaft 8; or the axial magnetic bearing 100 forms an axial bias magnetic circuit 001 with the bias magnetic flux provided by the radial magnetic bearing 200 in a radial direction away from the center of the rotating shaft 8; in two opposite quadrants, the magnetic flux in one of the quadrants is in a radial direction towards the center of the rotating shaft 8, and the magnetic flux in the other quadrant is in a radial direction away from the center of the rotating shaft 8.

[0068] The axial magnetic bearing of the present application provides bias magnetic flux in a radial direction towards the center of the rotating shaft or in a radial direction away from the center of the rotating shaft, thereby forming a relatively constant bias magnetic circuit, and the bias magnetic flux generated by the two axial stators is in a radial direction towards the inside or in a radial direction towards the outside, which can effectively increase the magnetic flux, thereby reducing the radial magnetic flux of the radial winding, reducing the power of the radial winding, improving the utilization rate of the axial magnetic bearing; in two opposite quadrants, the magnetic flux in one of the quadrants is in a radial direction towards the inside, and the magnetic flux in the other quadrant is in a radial direction towards the outside, which can enter the bearing rotor through the magnetic flux on the inside, and the magnetic circuit in the other quadrant can be led out to the stator yoke, thereby forming a closed loop, and such control means can greatly enhance the control ability, for example, if it is necessary to drive the rotating shaft in the upper left direction, the present application increases the winding current of the second quadrant and the fourth quadrant, which can simultaneously drive the second quadrant to move in the upper left direction and drive the fourth quadrant to move in the upper left direction, thereby effectively increasing the control ability and control efficiency of the rotating shaft relative to the existing magnetic suspension bearing.

[0069] In some embodiments, when the first axial stator 300 includes a first axial core 1 and a first axial winding 3, the first axial core 1 includes a first main body part 1a, a first annular part 1b, and a second annular part 1c, the second axial stator 400 includes a second axial core 2 and a second axial winding 4, the second axial core 2 includes a second main body part 2a, a third annular part 2b, and a fourth annular part 2c:

[0070] The radial winding 5 is located radially inside the second annular part 1c and the fourth annular part 2c, and the second annular part 1c and the fourth annular part 2c are located radially outside the radial stator yoke 11.

[0071] The present application also can greatly shorten the outer diameter of the radial stator and the thickness of the axial stator, and reduce the volume of the bearing stator, compared with the prior art in which the upper magnetic pole of the axial stator is located on the side of the axial stator in the axial direction, under the condition of the same radial and axial output.

[0072] The present application also provides an electric machine comprising the magnetic levitation active three-degree-of-freedom bearing according to any one of the preceding items.

[0073] The present application also provides a compressor comprising the magnetic levitation active three-degree-of-freedom bearing according to any one of the preceding items.

[0074] The above description is merely preferred embodiments of the present application but not to confine the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above description is merely preferred embodiments of the present application but not to confine the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A magnetically levitated active three-degree-of-freedom bearing, characterized in that: include: An axial magnetic bearing (100), a radial magnetic bearing (200), and a bearing rotor (7) are provided. Both the axial magnetic bearing (100) and the radial magnetic bearing (200) are sleeved on the outer periphery of a rotating shaft (8). 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 (7) is sleeved on the outer periphery of the rotating shaft (8) and can rotate with the rotating shaft (8). The radial stator (500) is located on the outer periphery of the bearing rotor (7) and can apply radial electromagnetic force to the bearing rotor (7). At least a portion of the structure of the first axial stator (300) is located at one axial end of the bearing rotor (7) along the axial direction of the rotating shaft (8), and at least a portion of the structure of the second axial stator (400) is located at one axial end of the bearing rotor (7). At the other axial end of 7), the first axial stator (300) and the second axial stator (400) can apply axial electromagnetic force to the bearing rotor (7); the radial stator (500) includes a radial core (6) and a radial winding (5), the radial core (6) is an annular structure and is sleeved on the radial outer side of the bearing rotor (7); at least a portion of the structure of the first axial stator (300) is located on the radial outer side of the radial winding (5), at least a portion of the structure of the first axial stator (300) is connected to the radial outer end of the radial core, at least a portion of the structure of the second axial stator (400) is located on the radial outer side of the radial winding (5), at least a portion of the structure of the second axial stator (400) is connected to the radial outer end of the radial core, such that the bias magnetic flux of the radial magnetic bearing (200) is provided by the axial magnetic bearing (100); The radial core (6) includes a radial stator yoke (11) and a radial stator pole (12). The radial stator yoke (11) is a ring structure. The radial outer end of the radial stator pole is connected to the radial stator yoke (11), and the radial inner end protrudes toward the bearing rotor (7) and has a radial working gap (15) between it and the bearing rotor (7). The radial winding (5) is wound on each radial stator pole. Furthermore, within the radial 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 sequentially in a counterclockwise direction. 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 magnetic circuit formed by the radial stator pole and the yoke portion in the second quadrant portion is connected to the magnetic circuit formed by the radial stator pole and the yoke portion in the fourth quadrant portion, forming a left radial control magnetic circuit (002). The magnetic circuit formed by the radial stator pole and the yoke portion in the first quadrant portion is connected to the magnetic circuit formed by the radial stator pole and the yoke portion in the third quadrant portion, forming a right radial control magnetic circuit (003).

2. The magnetically levitated active three-degree-of-freedom bearing according to claim 1, characterized in that: In the axial direction, the axial length of the radial core (6) is less than the axial length of the bearing rotor (7). The first axial end (71) of the bearing rotor (7) opposite to the first axial stator (300) protrudes by a first predetermined distance than the third axial end (61) of the radial core (6) opposite to the first axial stator (300), so that the third axial end (61) of the radial core (6) is retracted relative to the first axial end (71) to form a first space. At least a portion of the structure of the first axial stator (300) extends to connect with the radial outer end of the radial core (6). The second axial end (72) of the bearing rotor (7) opposite to the second axial stator (400) protrudes by a second predetermined distance than the fourth axial end (62) of the radial core (6) opposite to the second axial stator (400), so that the fourth axial end (62) of the radial core (6) is retracted relative to the second axial end (72) to form a second space, and at least a portion of the structure of the second axial stator (400) extends to connect with the radial outer end of the radial core (6).

3. The magnetically levitated active three-degree-of-freedom bearing according to claim 2, characterized in that: The first axial stator (300) includes a first axial core (1) and a first axial winding (3). The first axial core (1) is an annular structure, comprising a first main body (1a), a first annular portion (1b), and a second annular portion (1c). The first main body (1a) is a disc structure with a first central hole through which the rotating shaft (8) passes. The second annular portion (1c) is located radially outside the first annular portion (1b), and one end of the first annular portion (1b) is connected to the first axial winding (3). A main body (1a) is connected to the bearing rotor (7) and the other end extends toward the bearing rotor (7) to be opposite to the bearing rotor (7). One end of the second annular part (1c) is connected to the first main body (1a) and the other end extends to the radial outer end of the radial core (6) to form a first receiving groove (1d) between the radial outer side of the first annular part (1b) and the radial inner side of the second annular part (1c). The first axial winding (3) is disposed in the first receiving groove (1d) and wound around the inner circumference of the second annular part (1c).

4. The magnetically levitated active three-degree-of-freedom bearing according to claim 3, characterized in that: The first annular portion (1b) extends along the axial direction of the rotating shaft (8) and is spaced from the bearing rotor (7) by a third preset distance, forming an axial working clearance (16); the second annular portion (1c) also extends along the axial direction of the rotating shaft (8); The axial length of the second annular portion (1c) is greater than the axial length of the first annular portion (1b), and the end of the second annular portion (1c) opposite to the first main body portion (1a) is located on the radial outer side of the radial core (6).

5. The magnetically levitated active three-degree-of-freedom bearing according to claim 3, characterized in that: The second axial stator (400) includes a second axial core (2) and a second axial winding (4). The second axial core (2) is an annular structure, comprising a second main body (2a), a third annular part (2b), and a fourth annular part (2c). The second main body (2a) is a disc structure with a second central hole, through which the rotating shaft (8) passes. The fourth annular part (2c) is located radially outside the third annular part (2b), and one end of the third annular part (2b) is connected to the... The second main body (2a) is connected to the bearing rotor (7) and the other end extends toward the bearing rotor (7) to be opposite to the bearing rotor (7). One end of the fourth annular part (2c) is connected to the second main body (2a) and the other end extends to the radial outer end of the radial core (6) to form a second receiving groove (2d) between the radial outer side of the third annular part (2b) and the radial inner side of the fourth annular part (2c). The second axial winding (4) is disposed in the second receiving groove (2d) and wound around the inner circumference of the fourth annular part (2c).

6. The magnetically levitated active three-degree-of-freedom bearing according to claim 5, characterized in that: The third annular portion (2b) extends along the axial direction of the rotating shaft (8) and is spaced a fifth preset distance from the bearing rotor (7) to form an axial working clearance (16); the fourth annular portion (2c) also extends along the axial direction of the rotating shaft (8); The axial length of the fourth annular portion (2c) is greater than the axial length of the third annular portion (2b), and the end of the fourth annular portion (2c) opposite to the second main body portion (2a) is located on the radial outer side of the radial core (6). The fourth annular portion (2c) is connected to or spaced apart from the second annular portion (1c).

7. The magnetically levitated active three-degree-of-freedom bearing according to claim 5, characterized in that: The first axial winding (3) is energized in the opposite direction to the second axial winding (4).

8. The magnetically levitated active three-degree-of-freedom bearing according to claim 1, characterized in that: The number of radial stator poles is 4n, where n is a natural number.

9. The magnetically levitated active three-degree-of-freedom bearing according to claim 8, characterized in that: In each quadrant, two radial stator poles (12) are provided, and the radial stator pole located in the second quadrant is the upper left radial stator pole (17), and the radial stator pole located in the fourth quadrant is the lower right radial stator pole (18).

10. The magnetically levitated active three-degree-of-freedom bearing according to any one of claims 1-9, characterized in that: The axial magnetic bearing (100) provides bias magnetic flux to the radial magnetic bearing (200) in a radial direction toward the center of the rotating shaft (8) to form an axial bias magnetic circuit (001); or, the axial magnetic bearing (100) provides bias magnetic flux to the radial magnetic bearing (200) in a radial direction toward the center of the rotating shaft (8) to form an axial bias magnetic circuit (001); in the two diagonally opposite quadrants, the magnetic flux in one quadrant is radially toward the center of the rotating shaft (8), and the magnetic flux in the other quadrant is radially away from the center of the rotating shaft (8).

11. The magnetically levitated active three-degree-of-freedom bearing according to any one of claims 1-10, characterized in that: When the first axial stator (300) includes a first axial core (1) and a first axial winding (3), the first axial core (1) includes a first main body (1a), a first annular part (1b) and a second annular part (1c), and the second axial stator (400) includes a second axial core (2) and a second axial winding (4), the second axial core (2) includes a second main body (2a), a third annular part (2b) and a fourth annular part (2c): The radial winding (5) is located radially inside both the second annular portion (1c) and the fourth annular portion (2c), and both the second annular portion (1c) and the fourth annular portion (2c) are located radially outside the radial stator yoke (11).

12. An electric motor, characterized in that: Includes the magnetically levitated active three-degree-of-freedom bearing as described in any one of claims 1-11.

13. A compressor, characterized in that: Includes the magnetically levitated active three-degree-of-freedom bearing as described in any one of claims 1-11.

Images