Magnetic bearings, motors, compressors and air conditioners

Abstract

The present application provides a magnetic bearing, a motor, a compressor and an air conditioner. The magnetic bearing comprises an axial magnetic field control unit, a radial magnetic field control unit and a rotor assembly, wherein the axial magnetic field control unit is configured to provide an axial control magnetic field to the rotor assembly, and the radial magnetic field control unit is configured to provide a radial control magnetic field to the rotor assembly. A permanent magnet (1) is arranged between the axial magnetic field control unit and the radial magnetic field control unit, and the permanent magnet (1) provides a bias magnetic field for the axial magnetic field control unit and the radial magnetic field control unit at the same time. The magnetic bearing according to the present application can effectively shorten the axial length of the rotor, simplify the rotor structure, increase the natural frequency of the shaft, and improve the rotor limit speed.

Description

Technical Field

[0001] The present application relates to the field of magnetic suspension technology, and in particular to a magnetic suspension bearing, a motor, a compressor and an air conditioner. Background Art

[0002] Magnetic bearings have a series of excellent qualities such as no contact, no wear, high speed, high precision, no need for lubrication and sealing, etc. They are high-tech products integrating electromagnetism, electronic technology, control engineering, signal processing and mechanics.

[0003] Magnetic bearings are divided into three types: active, passive, and hybrid. Active magnetic bearings have high stiffness and can be precisely controlled, but the volume and power consumption required to produce unit load-bearing capacity are large; passive magnetic bearings use the attraction or repulsion between magnetic materials to achieve rotor suspension, and have relatively low stiffness and damping; hybrid magnetic bearings use permanent magnets to provide a bias magnetic field to replace the static bias magnetic field generated by the electromagnet in active magnetic bearings, reduce the ampere-turns of the control winding, reduce the volume of the bearing, and improve the bearing load-bearing capacity; hybrid magnetic bearings have irreplaceable advantages in areas with strict requirements on volume and power consumption, and magnetic bearings are mainly used in high-speed and ultra-high-speed applications. Therefore, the integration and miniaturization of magnetic suspension systems and improving the stability and reliability of control systems will be key research directions.

[0004] In order to achieve contactless support for the rotor, the magnetic suspension bearing system needs to control the five degrees of freedom in its space. The traditional magnetic suspension structure uses permanent magnet biased front and rear radial bearings to control the suspension control of the four degrees of freedom of the rotating shaft in the radial direction, and permanent magnet biased axial bearings to control the suspension control of the axial degree of freedom of the rotating shaft. Two sets of permanent magnet biased radial electromagnetic bearings and one set of permanent magnet biased axial bearings realize the five-degree-of-freedom suspension of the rotor space. The permanent magnet generates a bias magnetic field, and a closed loop is formed by auxiliary stator poles, rotating shaft, and radial stator poles to form a permanent magnet bias magnetic field, forming a bias magnetic flux in the radial stator pole and the main air gap of the rotating shaft. The radial horizontal and vertical control windings are fed with control current to generate a control magnetic field, and a control magnetic field is formed through the inside of the stator core and the rotating shaft to adjust the bias magnetic flux between the radial stator pole and the main air gap of the rotating shaft, so as to realize the suspension control of radial two degrees of freedom. The permanent magnet generates a bias magnetic field, which forms a closed loop through the stator core and thrust plate at the left and right ends to form a bias magnetic field, forming a bias magnetic flux in the air gap between the left and right stator cores and thrust plates, and the control winding is passed through a control current to form a control magnetic field, which forms a closed loop through the stator core and thrust plate to form a control magnetic circuit, and adjusts the bias magnetic flux in the stator core and thrust plate at the left and right ends to achieve axial suspension control of the rotating shaft. Each set of radial magnetic bearings controls the two radial degrees of freedom of the rotor, and the axial magnetic bearings control the axial translational degrees of freedom of the rotor.

[0005] The magnetic suspension system structure has the problems of parallel arrangement of radial and axial control systems, increased rotor length, large rotor deflection, small natural frequency and low rotor limit speed. Summary of the invention

[0006] Therefore, the technical problem to be solved by the present application is to provide a magnetic bearing, a motor, a compressor and an air conditioner, which can effectively shorten the axial length of the rotor, simplify the rotor structure, increase the natural frequency of the shaft, and increase the maximum speed of the rotor.

[0007] In order to solve the above problems, the present application provides a magnetic levitation bearing, including an axial magnetic field control part, a radial magnetic field control part and a rotor assembly. The axial magnetic field control part is configured to provide an axial control magnetic field to the rotor assembly, and the radial magnetic field control part is configured to provide a radial control magnetic field to the rotor assembly. A permanent magnet is arranged between the axial magnetic field control part and the radial magnetic field control part, and the permanent magnet provides a bias magnetic field for the axial magnetic field control part and the radial magnetic field control part at the same time.

[0008] Preferably, the rotor assembly comprises a rotor core, the axial magnetic field control portion comprises an axial control end arranged opposite to an end surface of the rotor core, and the axial control end is provided with an axial control winding.

[0009] Preferably, the rotor assembly includes a rotor core, the radial magnetic field control portion includes a radial control end arranged opposite to the outer circumferential surface of the rotor core, and the radial control end is provided with a radial control winding.

[0010] Preferably, the permanent magnet is arranged on the outer peripheral side of the axial magnetic field control portion, and the radial magnetic field control portion is arranged on the outer peripheral side of the permanent magnet.

[0011] Preferably, the axial magnetic field control unit further comprises an axial iron core, the axial iron core is arranged opposite to the end surface of the rotor iron core, and the axial control winding is arranged at one end of the axial iron core facing the rotor iron core.

[0012] Preferably, the axial core includes a magnetic conductive plate, which is provided with an annular protrusion protruding toward the rotor core, an annular wire groove is provided on the annular protrusion, the axial control winding is arranged in the annular wire groove, and the permanent magnet is arranged on the outer peripheral side of the magnetic conductive plate.

[0013] Preferably, the radial magnetic field control part includes a magnetic ring and a radial iron core. The magnetic ring is arranged on the outer peripheral side of the permanent magnet. The radial iron core and the magnetic ring are arranged in sequence along the axial direction. The radial iron core is sleeved outside the rotor iron core. The radial iron core includes radial teeth, and the radial control winding is wound on the radial teeth.

[0014] Preferably, the radial core is divided into a plurality of core segments along the circumferential direction, and the plurality of core segments are magnetically isolated by magnetic isolation structures.

[0015] Preferably, the magnetic isolation structure comprises a magnetic isolation plate, and the magnetic isolation plate is arranged between two adjacent core segments.

[0016] Preferably, the magnetic isolation structure also includes a magnetic isolation ring, which is spaced between the magnetic conductive ring and the radial iron core, a magnetic isolation plate is arranged on the magnetic isolation ring, an avoidance groove is arranged on the magnetic isolation ring, a magnetic conductive protrusion is arranged on the magnetic conductive ring, the magnetic conductive protrusion is arranged in the avoidance groove, and a magnetic conductive channel is formed between the magnetic conductive ring and the radial iron core through the magnetic conductive protrusion.

[0017] Preferably, the magnetic isolation plates are evenly spaced along the circumference of the magnetic isolation ring, the avoidance grooves are evenly spaced along the circumference of the magnetic isolation ring, and the magnetic isolation plates and the avoidance grooves are alternately arranged along the circumference of the magnetic isolation ring.

[0018] Preferably, the magnetic isolation plate and the magnetic isolation ring are integrally formed.

[0019] Preferably, the avoidance groove is located in the middle of two adjacent magnetic isolation plates along the circumferential direction.

[0020] Preferably, the radial core is divided into four core segments along the circumferential direction, and the four core segments are divided into two relatively arranged groups, wherein one group of core segments is arranged along the vertical direction to adjust the upper and lower positions of the rotor assembly, and the other group of core segments is arranged along the horizontal direction to adjust the horizontal position of the rotor assembly; or, the four core segments are evenly arranged along the circumference of the radial core, and two core segments are located on the upper side, and two core segments are located on the lower side, and the two core segments on the upper side and the two core segments on the lower side are symmetrical about the horizontal plane.

[0021] Preferably, axial magnetic field control parts are respectively provided at both ends of the rotor assembly, and the axial magnetic field control parts at both ends of the rotor assembly are separately designed and independently controlled; and / or, radial magnetic field control parts are respectively provided at both ends of the rotor assembly, and the radial magnetic field control parts at both ends of the rotor assembly are separately designed and independently controlled.

[0022] Preferably, the axial magnetic field control portion and the radial magnetic field control portion are independent of each other.

[0023] Preferably, the magnetic suspension bearing further comprises a shell, and the axial magnetic field control part, the radial magnetic field control part and the permanent magnet are fixedly installed in the shell.

[0024] According to another aspect of the present application, a motor is provided, comprising a magnetic bearing, wherein the magnetic bearing is the magnetic bearing described above.

[0025] According to another aspect of the present application, a compressor is provided, comprising a magnetic bearing, wherein the magnetic bearing is the magnetic bearing described above.

[0026] According to another aspect of the present application, an air conditioner is provided, comprising a magnetic bearing, wherein the magnetic bearing is the magnetic bearing described above.

[0027] The magnetic bearing provided by the present application includes an axial magnetic field control unit, a radial magnetic field control unit and a rotor assembly, wherein the axial magnetic field control unit is configured to provide an axial control magnetic field to the rotor assembly, and the radial magnetic field control unit is configured to provide a radial control magnetic field to the rotor assembly. A permanent magnet is arranged between the axial magnetic field control unit and the radial magnetic field control unit, and the permanent magnet provides a bias magnetic field for the axial magnetic field control unit and the radial magnetic field control unit at the same time. The magnetic bearing uses the axial magnetic field control unit to control the axial displacement of the rotor assembly, and uses the radial magnetic field control unit to control the radial displacement of the rotor assembly. At the same time, the axial magnetic field control unit and the radial magnetic field control unit located at the same end of the rotor assembly share a permanent magnet, and a permanent magnet is used to simultaneously form a radial bias magnetic field and an axial bias magnetic field, thereby realizing an integrated design of the axial and radial displacement control of the magnetic bearing, so that the radial and axial force positions of the motor rotor assembly are integrated, thereby effectively shortening the axial length of the rotor assembly, simplifying the rotor structure, increasing the natural frequency of the shaft, and increasing the limiting speed of the rotor assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A three-dimensional cross-sectional schematic diagram of a magnetic bearing according to an embodiment of the present application;

[0029] Figure 2 This is a schematic diagram of the exploded structure of a magnetic bearing according to an embodiment of the present application;

[0030] Figure 3 A schematic diagram of the magnetic structure of a magnetic bearing according to an embodiment of the present application;

[0031] Figure 4 for Figure 3 Schematic diagram of the magnetic structure in the AA direction.

[0032] The reference numerals are as follows:

[0033] 1. Permanent magnet; 2. Rotor core; 3. Axial control winding; 4. Radial control winding; 5. Axial core; 6. Magnetic plate; 7. Annular protrusion; 8. Annular wire groove; 9. Radial core; 10. Magnetic ring; 11. Radial teeth; 12. Magnetic isolation plate; 13. Magnetic isolation ring; 14. Magnetic protrusion; 15. Avoidance groove; 16. Shell. DETAILED DESCRIPTION

[0034] See also Figures 1 to 4As shown, according to an embodiment of the present application, the magnetic suspension bearing includes an axial magnetic field control part, a radial magnetic field control part and a rotor assembly, the axial magnetic field control part is configured to provide an axial control magnetic field to the rotor assembly, the radial magnetic field control part is configured to provide a radial control magnetic field to the rotor assembly, and a permanent magnet 1 is arranged between the axial magnetic field control part and the radial magnetic field control part, and the permanent magnet 1 provides a bias magnetic field for the axial magnetic field control part and the radial magnetic field control part at the same time. In this embodiment, the rotor assembly is mounted on the rotating shaft and rotates synchronously with the rotating shaft.

[0035] The magnetic bearing uses an axial magnetic field control unit to control the axial displacement of the rotor assembly, and uses a radial magnetic field control unit to control the radial displacement of the rotor assembly. At the same time, the axial magnetic field control unit and the radial magnetic field control unit located at the same end of the rotor assembly share a permanent magnet 1. A permanent magnet 1 is used to simultaneously form a radial bias magnetic field and an axial bias magnetic field, thereby realizing an integrated design of the axial and radial displacement control of the magnetic bearing, and integrating the radial and axial force positions of the motor rotor assembly. Therefore, the axial length of the rotor assembly can be effectively shortened, the rotor structure can be simplified, the natural frequency of the shaft can be increased, and the limiting speed of the rotor assembly can be increased.

[0036] In this embodiment, since the axial magnetic field control unit and the radial magnetic field control unit share a permanent magnet 1, the permanent magnet 1 can provide axial and radial bias magnetic fields at the same time, thereby saving the amount of permanent magnets, improving the utilization efficiency of the permanent magnets 1, and saving costs. In addition, since the number of permanent magnets 1 is reduced, the space occupied by the permanent magnets can also be saved, further realizing the miniaturization design of the magnetic suspension bearing, making the structure of the magnetic suspension bearing more compact.

[0037] In one embodiment, the rotor assembly includes a rotor core 2, and the axial magnetic field control unit includes an axial control end arranged opposite to the end surface of the rotor core 2, and the axial control end is provided with an axial control winding 3. In this embodiment, the axial control winding 3 is sleeved outside the rotating shaft and is arranged at the axial control end. The axial magnetic field control unit forms an axial control magnetic field with the rotor core 2 through the axial control winding 3, so the rotor core 2 can be used to provide a thrust function, and there is no need to set a separate thrust bearing, which can simplify the rotating shaft structure and improve the reliability and stability of the rotating shaft operation.

[0038] In one embodiment, the rotor assembly includes a rotor core 2, and the radial magnetic field control unit includes a radial control end arranged relative to the outer peripheral surface of the rotor core 2, and the radial control end is provided with a radial control winding 4. The radial magnetic field control unit is arranged relative to the outer peripheral surface of the rotor core 2, and can adjust the radial displacement of the rotor assembly by adjusting the magnetic field of the radial control winding 4. Generally speaking, the radial displacement adjustment of the rotor assembly is mainly in the vertical direction and the horizontal direction. Therefore, the radial magnetic field control unit is also correspondingly designed into four parts, the upper and lower parts are a group to achieve the vertical displacement adjustment of the rotor assembly, and the left and right parts are a group to achieve the horizontal displacement adjustment of the rotor assembly, so that the displacement adjustment of the magnetic suspension bearing is flexible and convenient.

[0039] In the embodiment of the present application, the axial magnetic field control part, the permanent magnet 1 and the radial magnetic field control part are combined together, and the three are equivalent to being combined into a whole, thus forming an integrated structure of the radial bearing and the axial bearing, and the force-bearing position also forms an integrated structure, which effectively reduces the occupied length of the three in the axial direction of the rotor assembly, thereby shortening the axial length of the rotor assembly, simplifying the structure of the rotor assembly, increasing the natural frequency of the shaft, and improving the rotor limit speed.

[0040] In one embodiment, the permanent magnet 1 is arranged on the outer peripheral side of the axial magnetic field control part, and the radial magnetic field control part is arranged on the outer peripheral side of the permanent magnet 1. In this embodiment, since the axial magnetic field control part, the permanent magnet 1 and the radial magnetic field control part are arranged in sequence along the radial direction, and the three are fitted to each other, the positions of the three can be reasonably arranged, and the occupied length of the three in the axial direction of the rotor assembly can be effectively reduced, thereby further shortening the axial length of the rotor assembly, simplifying the structure of the rotor assembly, increasing the natural frequency of the shaft, and improving the rotor limit speed.

[0041] In one embodiment, the axial magnetic field control part, the permanent magnet 1 and the radial magnetic field control part can also be arranged in sequence along the axial direction and fit closely together, which can also reduce the occupied length of the three in the axial direction of the rotor assembly to a certain extent.

[0042] In one embodiment, the axial magnetic field control unit further includes an axial core 5, which is arranged opposite to the end surface of the rotor core 2, and the axial control winding 3 is arranged at one end of the axial core 5 facing the rotor core 2. An annular wire groove 8 is arranged on the end surface of the axial core 5 facing the rotor core 2, and the axial control winding 3 is installed in the annular wire groove 8. The side wall of the annular wire groove 8 can form a magnetic conductive channel, so that the magnetic lines of force reach the rotor core 2 through the axial core 5, forming an axial thrust, and then the axial position of the rotor assembly can be adjusted.

[0043] In one embodiment, the axial core 5 includes a magnetic plate 6, the magnetic plate 6 is provided with an annular protrusion 7 protruding toward the rotor core 2, an annular groove 8 is provided on the annular protrusion 7, the axial control winding 3 is arranged in the annular groove 8, and the permanent magnet 1 is arranged on the outer peripheral side of the magnetic plate 6. In this embodiment, the magnetic plate 6 is used to cooperate with the permanent magnet 1 to form a radial path, so that the axial bias magnetic field generated by the permanent magnet 1 can reach the annular protrusion 7 through the magnetic plate 6, and then reach the rotor core 2 through the annular protrusion 7, thereby forming a closed magnetic circuit structure, and the axial position of the rotor assembly can be adjusted. By providing the annular protrusion 7, the structure of the annular protrusion 7 can be used to regularize the magnetic lines of force, so that the axial force generated between the axial core 5 and the rotor core 2 is more concentrated, the action position is more accurate, and the consistency of the axial action position at both ends of the rotor core 2 can be more conveniently ensured.

[0044] In one embodiment, the radial magnetic field control unit includes a magnetic ring 10 and a radial core 9, the magnetic ring 10 is arranged on the outer peripheral side of the permanent magnet 1, the radial core 9 and the magnetic ring 10 are arranged in sequence along the axial direction, the radial core 9 is sleeved outside the rotor core 2, the radial core 9 includes radial teeth 11, and the radial control winding 4 is wound on the radial teeth 11. In this embodiment, the magnetic ring 10 cooperates with the permanent magnet 1 to form a magnetic channel of the radial bias magnetic field, guides the magnetic lines of force generated by the permanent magnet 1 to the radial core 9, and then reaches the rotor core 2 through the radial core 9 to form a radial force, and the radial control winding 4 is wound on the radial teeth 11, which can form a control magnetic field, adjust the radial force, and then realize the radial position adjustment of the rotor assembly.

[0045] For radial bearings, they are mainly used to adjust the radial position of the rotor assembly. Therefore, it is necessary to ensure that the flow of magnetic lines of force is concentrated in the radial direction. After reaching the radial core 9, the magnetic lines of force generated by the permanent magnet 1 will be divided into two parts. One part of the magnetic lines of force will reach the rotor core 2 from the radial teeth 11 to form a radial force, and the other part of the magnetic lines of force will flow along the circumference of the radial core 9. The magnetic lines of force in multiple different areas flowing along the circumferential flow of the radial core 9 are in opposite directions, which will cause the magnetic lines of force to cancel each other out, which will not only affect the permanent magnet 1 to generate an effective radial bias magnetic field, but also make it difficult to ensure that the radial core 9 generates an effective radial effect, and it is difficult to form an effective radial adjustment effect on the rotor assembly. Therefore, in order to avoid this situation, the radial core 9 needs to be segmented to cut off the magnetic lines of force between adjacent core segments so that the magnetic lines of force are concentrated on the radial teeth 11, thereby forming an effective radial magnetic field and forming an effective radial adjustment of the rotor assembly.

[0046] In one embodiment, the radial core 9 is divided into a plurality of core segments along the circumferential direction, and the plurality of core segments are magnetically isolated by a magnetic isolation structure. In this embodiment, each core segment includes three radial teeth 11, and the widths of the three radial teeth 11 are different, wherein the tooth width of the radial tooth 11 located in the middle position is greater than or equal to the sum of the widths of the two radial teeth 11 on both sides, which can ensure that the three radial teeth 11 can form two complete closed magnetic circuits and provide a greater radial force, and can ensure that the radial teeth 11 in the middle have sufficient width to accommodate sufficient magnetic lines of force to pass through, thereby improving the utilization rate of the permanent magnet 1. As a preferred embodiment, the width of the radial tooth 11 in the middle is the sum of the widths of the two radial teeth 11 on both sides, and the widths of the two radial teeth 11 on both sides are equal, which can further improve the balance of the radial forces of each core segment of the radial core 9.

[0047] In one embodiment, the magnetic isolation structure includes a magnetic isolation plate 12, and the magnetic isolation plate 12 is arranged between two adjacent core segments. In this embodiment, the magnetic isolation plate 12 is a flat plate structure, and the shape of the plate surface is consistent with the cross-sectional shape of the yoke of the core segment, so as to form a good magnetic field isolation effect, and at the same time, after the core segments are combined together, they are still a complete annular core structure.

[0048] In one embodiment, the core segment and the magnetic isolation plate 12 can be fixed together by bonding, or the core segment and the magnetic isolation plate 12 can be fixedly connected together by other means. In this case, the magnetic ring 10 can directly contact the core segment to conduct magnetic lines of force. In order to ensure that the magnetic lines of force of the magnetic ring 10 are accurately transferred and can effectively form multiple closed magnetic circuits, preferably, the magnetic ring 10 is provided with multiple magnetic protrusions 14 at the end facing the core segment, and the magnetic protrusions 14 are arranged one by one with the core segments, and the circumferential width of each magnetic protrusion 14 is not greater than the circumferential width of the radial teeth 11 in the middle of each core segment, and each magnetic protrusion 14 is arranged corresponding to the radial teeth 11 in the middle.

[0049] In one embodiment, the magnetic isolation structure further includes a magnetic isolation ring 13, which is arranged between the magnetic conductive ring 10 and the radial core 9, and a magnetic isolation plate 12 is arranged on the magnetic isolation ring 13, and a avoidance groove 15 is arranged on the magnetic isolation ring 13. A magnetic conductive protrusion 14 is arranged on the magnetic conductive ring 10, and the magnetic conductive protrusion 14 is arranged in the avoidance groove 15. The magnetic conductive ring 10 forms a magnetic conductive channel with the radial core 9 through the magnetic conductive protrusion 14. In this embodiment, the magnetic isolation ring 13 can block the magnetic lines of force between the magnetic conductive ring 10 and the radial core 9, and the radial bias magnetic field generated by the permanent magnet 1 can only reach the radial core 9 through the magnetic conductive protrusion 14, so as to generate a closed magnetic circuit. By providing the magnetic isolation ring 13, and providing the avoidance groove 15 on the magnetic isolation ring 13, and providing the magnetic conductive protrusion 14 passing through the avoidance groove 15 on the magnetic conductive ring 10, the flow direction of the magnetic lines of force can be accurately controlled, and the radial adjustment effect of the radial core 9 can be more accurately controlled.

[0050] In one embodiment, the magnetic isolation plates 12 are evenly spaced along the circumference of the magnetic isolation ring 13, the avoidance grooves 15 are evenly spaced along the circumference of the magnetic isolation ring 13, and the magnetic isolation plates 12 and the avoidance grooves 15 are alternately arranged along the circumference of the magnetic isolation ring 13. This structural design can avoid the conflict between the setting position of the avoidance grooves 15 and the setting position of the magnetic isolation ring 13, ensure the rationality of the arrangement of the avoidance grooves 15 and the magnetic isolation plates 12 along the circumference of the magnetic isolation ring 13, and thus more effectively realize the radial position adjustment of the rotor assembly.

[0051] In one embodiment, the magnetic isolation plate 12 and the magnetic isolation ring 13 are integrally formed, which can not only reduce the difficulty of processing and improve the processing efficiency by utilizing the integral structure between the magnetic isolation plate 12 and the magnetic isolation ring 13, but also effectively ensure the structural strength between the magnetic isolation plate 12 and the magnetic isolation ring 13. In addition, the magnetic isolation plate 12 is fixed on the magnetic isolation ring 13, which can also facilitate the installation and fixation of each core segment, and the magnetic isolation ring 13 is used to provide a mounting structure for the radial core.

[0052] In one embodiment, the avoidance groove 15 is located in the middle position of two adjacent magnetic isolation plates 12 along the circumferential direction, so that the magnetic isolation plates 12 and the magnetic conductive protrusions 14 can be evenly arranged along the circumference of the magnetic isolation ring 13, so that the magnetic isolation part and the magnetic conductive part are evenly distributed, thereby ensuring that the radial force applied by the radial core 9 to the rotor core 2 is evenly distributed along the circumferential direction.

[0053] In one embodiment, the radial core 9 is divided into four core segments along the circumferential direction, and the four core segments are divided into two groups arranged opposite to each other, one group of core segments is arranged along the vertical direction to adjust the upper and lower positions of the rotor assembly, and the other group of core segments is arranged along the horizontal direction to adjust the horizontal position of the rotor assembly. The four core segments have the same structure, so that the four core segments are evenly distributed along the circumferential direction. When no radial control magnetic field is applied, the radial force on the rotor core 2 under the same current is the same, which can improve the consistency of the force. In this way, the radial control magnetic field can more accurately control the force on the rotor core 2, and the radial position adjustment is more accurate and reliable.

[0054] In one embodiment, the four core segments are evenly arranged along the circumference of the radial core, and two core segments are located on the upper side, and two core segments are located on the lower side. The two core segments located on the upper side and the two core segments located on the lower side are symmetrical about the horizontal plane. Since the four core segments are evenly distributed along the circumference, the two core segments located at the first end of the horizontal diameter of the radial core and the two core segments located at the second end of the horizontal diameter of the radial core are also symmetrical about the vertical plane, so that the four core segments are grouped in pairs. When the same current is passed, they can apply forces of the same magnitude and opposite directions to the rotor core 2, so that the rotor core 2 remains in the middle position, thereby improving the accuracy of the radial core in adjusting the radial position of the rotor core 2.

[0055] In one embodiment, the permanent magnet 1 is an annular structure, which is sleeved outside the magnetic conductive plate 6 of the axial iron core 5 and has an interference fit with the magnetic conductive plate 6. The magnetic conductive ring 10 is sleeved outside the permanent magnet 1 and has an interference fit with the permanent magnet 1, so that the axial magnetic field control part, the permanent magnet 1 and the radial magnetic field control part form an integrated structure fixed together.

[0056] The two ends of the rotor assembly are respectively provided with axial magnetic field control parts, which are designed separately and controlled independently. The front and rear axial bearings are designed separately and have independent processing systems, so that the limit load of the axial bearing is not limited by the magnetic field of the permanent magnet 1. Under the performance conditions of the axial control winding 3 and the magnetic conductive material, the axial output can be continuously improved according to the demand, thereby reducing the material cost of the permanent magnet and improving the performance of the magnetic suspension bearing.

[0057] In one embodiment, radial magnetic field control parts are respectively provided at both ends of the rotor assembly, and the radial magnetic field control parts at both ends of the rotor assembly are separately designed and independently controlled. In this embodiment, radial magnetic field control parts are respectively provided at both ends of the rotor assembly, and each radial magnetic field control part is separately designed and exists independently, so that each independent magnetic field control part can control the radial position of the rotor assembly at its end, and can achieve fine adjustment of the radial position of the rotor assembly, with higher control accuracy.

[0058] In one embodiment, the axial magnetic field control part and the radial magnetic field control part are independent of each other and do not interfere with each other, and share a permanent magnet 1, which effectively shortens the axial occupied space, reduces the number of parts, and saves material costs.

[0059] In this embodiment, the front and rear ends of the rotating shaft are respectively provided with independently controlled axial magnetic field control parts and radial magnetic field control parts. The axial magnetic field control part can be used to realize axial position adjustment, and the radial magnetic field control part can be used to realize vertical direction, horizontal direction, front and rear tilt, up and down tilt and other multiple degrees of freedom adjustment, thereby realizing five-degree-of-freedom suspension control of the motor rotor.

[0060] In one embodiment, the magnetic bearing further comprises a housing 16, and the axial magnetic field control unit, the radial magnetic field control unit and the permanent magnet 1 are fixedly installed in the housing 16. In this embodiment, the housing 16 comprises an end cover and an outer cylinder, wherein the end cover is provided with an axial hole for the main shaft to pass through, the axial core 5, the permanent magnet 1 and the magnetic conductive ring 10 are all matched with the end cover to form an axial stop, and the outer cylinder is sleeved outside the magnetic conductive ring 10, the magnetic isolation ring 13 and the radial core 9, and can form an installation and fixation for the magnetic conductive ring 10, the magnetic isolation ring 13 and the radial core 9. The inner hole diameter of the end cover is smaller than the outer diameter of the magnetic plate 6 of the axial core 5, and the axial position of the magnetic plate 6 can be limited by the end cover to prevent the magnetic plate 6 from escaping from the axial hole of the end cover. The axial length of the outer cylinder is greater than or equal to the total axial length of the magnetic ring 10, the magnetic isolation ring 13 and the radial core 9 after being combined, so that the magnetic ring 10, the magnetic isolation ring 13 and the radial core 9 can be included, and the shell 16 can also be used to protect the magnetic ring 10, the magnetic isolation ring 13 and the radial core 9.

[0061] Since the axial bearing and the radial bearing are both installed and fixed in the housing 16, a structurally stable axial-radial integrated magnetic suspension structure can be formed through the housing 16, and the structural stability is better.

[0062] In this embodiment, the shell 16, axial bearing, permanent magnet 1 and radial bearing located at the front end form a front bearing structure, and the shell 16, axial bearing, permanent magnet 1 and radial bearing located at the rear end form a rear bearing structure. The two bearing structures are designed separately and independently of each other, which can further improve the flexibility of the position adjustment of the rotor core.

[0063] The assembly process of the magnetic bearing is as follows:

[0064] The magnetic ring 10 is fixed inside the housing 16 by providing a shrink fit and screw connection to achieve radial and axial positioning. The axial control winding 3 is embedded in the groove of the axial core 5 by potting and self-tapping thread connection to achieve axial and radial positioning of the axial control winding 3, forming an axial bearing assembly. The radial control winding 4 is wound on the main magnetic pole of the radial core 9 and fixed by winding and varnishing to form a radial bearing assembly. The radial bearing assembly is embedded in the magnetic isolation structure to form a radial bearing assembly. The housing 16 is heated and expanded, and the axial bearing, permanent magnet 1, and radial bearing are installed in the housing 16 in sequence to achieve radial positioning of the bearing assembly. The axial positioning of the bearing assembly is achieved by threaded connection to form a front axial-radial bearing assembly. Similarly, the installation process of the rear axial-radial bearing assembly is the same. The front and rear axial-radial bearing assemblies are respectively installed at both ends of the rotor core 2 to achieve the installation of a new type of thrust-free five-degree-of-freedom magnetic suspension bearing.

[0065] Combine the following Figures 1 to 4 The working principle of the magnetic bearing according to the embodiment of the present application is described.

[0066] like Figure 1 and 2 As shown, the annular permanent magnet 1 generates a bias magnetic field, which forms a closed loop through the upper magnetic pole of the axial core 5, the rotor core 2, the radial core 9, and the magnetic ring 10 to form an axial-radial bias magnetic field. The axial-radial bias magnetic field forms an axial bias magnetic flux in the air gap between the rotor core 2 and the upper magnetic pole of the axial core 5, and a radial bias magnetic flux in the air gap between the rotor core 2 and the radial core 9. The axial control winding 3 is fed with a control current to form a control magnetic field through the upper and lower magnetic poles of the axial core 5 and the rotor core 2 to form a closed loop, forming an axial control magnetic field, adjusting the magnetic flux density in the axial air gap, and realizing the axial suspension control of the rotor core 2. The radial control winding 4 is fed with a control current to generate a control magnetic field through the main magnetic pole of the radial core 9, the rotor core 2, and the auxiliary magnetic poles on both sides of the radial core 9 to form a closed loop, forming a radial control magnetic field, adjusting the magnetic flux density at the magnetic pole gap between the radial core 9 and the rotor core 2, and realizing the front and rear radial four-degree-of-freedom suspension control of the rotor assembly, thereby realizing the five-degree-of-freedom suspension of the motor rotor. The radial bearing and axial core are integrated, and the radial-axial force position of the motor rotor is integrated, which effectively shortens the axial length of the rotor, simplifies the rotor structure, increases the natural frequency of the shaft, and increases the rotor limit speed. The front and rear axial cores are separated and do not interfere with each other. The axial output is not limited by the permanent magnet. Under the conditions of meeting the performance of the control winding and magnetic conductive materials, the axial load can be continuously increased.

[0067] When the rotating shaft is in the axial equilibrium position, the magnetic flux density at the gap between the rotor core 2 and the left and right axial cores 5 is the same, and the rotor is under balanced load. When the rotating shaft is subjected to a left impact load, the rotating shaft deviates to the left, the gap between the rotor core 2 and the left axial core 5 decreases, the bias magnetic flux density on the left increases, the gap on the right increases, the bias magnetic flux density on the right decreases, and the axial suction force of the left axial core 5 on the rotor core 2 is greater than that of the right axial core 5. Without external control, the rotating shaft will continue to deviate to the left. The left control current decreases and the right control current increases, and the bias magnetic flux density at the left and right air gaps is adjusted to make the magnetic flux density in the right air gap greater than that on the left. The rotating shaft will deviate to the right. If the axial load to the left is large, the left control current will stop decreasing after it decreases to 0, and the right control current will continue to increase until the axial load is balanced, so that the rotating shaft deviates to the right until the equilibrium position is reached, and the suspension control of the axial degree of freedom is realized.

[0068] When the rotating shaft is in the radial equilibrium position, the gap between the upper and lower magnetic poles of the rotor core 2 and the radial core 9 is the same, the magnetic flux density of the bias magnetic field in the gap is the same, the upper and lower magnetic poles of the radial core 9 have the same suction force on the rotor core 2, and the rotor core 2 is continuously in the equilibrium position. When the rotating shaft is subjected to a vertical downward impact load, the rotating shaft deviates downward, the upper gap becomes larger, the lower gap becomes smaller, the magnetic flux density of the lower gap is greater than the magnetic flux density of the upper gap, and the downward suction force of the radial core 9 on the rotor core 2 is greater than the upward suction force. Without external regulation, the rotating shaft will continue to deviate downward. The radial control winding 4 passes a control current to generate a control magnetic field, increase the magnetic flux density in the upper gap, and reduce the magnetic flux density in the lower gap, so that the upward suction force of the radial core 9 on the rotor core 2 is greater than the downward suction force, and the motor rotor deviates upward until the equilibrium position, realizing the front and rear radial four-degree-of-freedom suspension control.

[0069] According to an embodiment of the present application, the motor includes a magnetic bearing, which is the magnetic bearing mentioned above.

[0070] According to an embodiment of the present application, the compressor includes a magnetic suspension bearing, which is the magnetic suspension bearing mentioned above.

[0071] According to an embodiment of the present application, the air conditioner includes a magnetic suspension bearing, which is the magnetic suspension bearing mentioned above.

[0072] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0073] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A magnetic bearing, characterized in that: The invention comprises an axial magnetic field control part, a radial magnetic field control part and a rotor assembly, wherein the axial magnetic field control part is configured to provide an axial control magnetic field to the rotor assembly, and the radial magnetic field control part is configured to provide a radial control magnetic field to the rotor assembly, and a permanent magnet (1) is arranged between the axial magnetic field control part and the radial magnetic field control part, and the permanent magnet (1) provides a bias magnetic field for the axial magnetic field control part and the radial magnetic field control part at the same time; the rotor assembly comprises a rotor core (2), the axial magnetic field control part comprises an axial control end arranged opposite to an end surface of the rotor core (2), and the axial control end is provided with an axial control winding (3); The radial magnetic field control portion comprises a radial control end arranged opposite to the outer peripheral surface of the rotor core (2), the radial control end being provided with a radial control winding (4); The radial magnetic field control unit comprises a magnetic conductive ring (10) and a radial iron core (9), the magnetic conductive ring (10) being arranged on the outer peripheral side of the permanent magnet (1), the radial iron core (9) and the magnetic conductive ring (10) being arranged in sequence along the axial direction, the radial iron core (9) being sleeved outside the rotor iron core (2), the radial iron core (9) comprising radial teeth (11), and the radial control winding (4) being wound on the radial teeth (11); The radial iron core (9) is divided into a plurality of iron core segments along the circumferential direction, and the plurality of iron core segments are magnetically isolated by magnetic isolation structures; The magnetic isolation structure comprises a magnetic isolation plate (12), wherein the magnetic isolation plate (12) is arranged at intervals between two adjacent core segments; The magnetic isolation structure further comprises a magnetic isolation ring (13), wherein the magnetic isolation ring (13) is arranged between the magnetic conductive ring (10) and the radial iron core (9), the magnetic isolation plate (12) is arranged on the magnetic isolation ring (13), the magnetic isolation ring (13) is provided with an avoidance groove (15), the magnetic conductive ring (10) is provided with a magnetic conductive protrusion (14), the magnetic conductive protrusion (14) is arranged in the avoidance groove (15), and the magnetic conductive ring (10) forms a magnetic conductive channel with the radial iron core (9) through the magnetic conductive protrusion (14).

2. The magnetic bearing according to claim 1, characterized in that: The permanent magnet (1) is arranged on the outer peripheral side of the axial magnetic field control portion, and the radial magnetic field control portion is arranged on the outer peripheral side of the permanent magnet (1).

3. The magnetic bearing according to claim 1, characterized in that: The axial magnetic field control unit further comprises an axial iron core (5), the axial iron core (5) being arranged opposite to an end surface of the rotor iron core (2), and the axial control winding (3) being arranged at one end of the axial iron core (5) facing the rotor iron core (2).

4. The magnetic bearing according to claim 3, characterized in that: The axial core (5) comprises a magnetic conductive plate (6), the magnetic conductive plate (6) being provided with an annular protrusion (7) protruding toward the rotor core (2), an annular wire groove (8) being provided on the annular protrusion (7), the axial control winding (3) being arranged in the annular wire groove (8), and the permanent magnet (1) being arranged on the outer peripheral side of the magnetic conductive plate (6).

5. The magnetic bearing according to claim 1, characterized in that: The magnetic isolation plates (12) are evenly spaced along the circumference of the magnetic isolation ring (13), the avoidance grooves (15) are evenly spaced along the circumference of the magnetic isolation ring (13), and the magnetic isolation plates (12) and the avoidance grooves (15) are alternately arranged along the circumference of the magnetic isolation ring (13).

6. The magnetic bearing according to claim 1, characterized in that: The magnetic isolation plate (12) and the magnetic isolation ring (13) are integrally formed.

7. The magnetic bearing according to claim 5, characterized in that: The avoidance groove (15) is located in the middle of two adjacent magnetic isolation plates (12) along the circumferential direction.

8. The magnetic bearing according to claim 1, characterized in that: The radial core (9) is divided into four core segments along the circumferential direction, and the four core segments are divided into two groups arranged opposite to each other, wherein one group of core segments is arranged along the vertical direction to adjust the upper and lower positions of the rotor assembly, and the other group of core segments is arranged along the horizontal direction to adjust the horizontal position of the rotor assembly; or, the four core segments are evenly arranged along the circumferential direction of the radial core, and two of the core segments are located on the upper side, and two of the core segments are located on the lower side, and the two core segments located on the upper side and the two core segments located on the lower side are symmetrical about the horizontal plane.

9. The magnetic bearing according to any one of claims 1 to 8, characterized in that: The axial magnetic field control parts are respectively provided at both ends of the rotor assembly, and the axial magnetic field control parts at both ends of the rotor assembly are separately designed and independently controlled; and / or, the radial magnetic field control parts are respectively provided at both ends of the rotor assembly, and the radial magnetic field control parts at both ends of the rotor assembly are separately designed and independently controlled.

10. The magnetic bearing according to any one of claims 1 to 8, characterized in that: The axial magnetic field control portion and the radial magnetic field control portion are independent of each other.

11. The magnetic bearing according to any one of claims 1 to 8, characterized in that: The magnetic suspension bearing further comprises a housing (16), wherein the axial magnetic field control portion, the radial magnetic field control portion and the permanent magnet (1) are fixedly mounted in the housing (16).

12. A motor, characterized in that: It comprises a magnetic bearing, and the magnetic bearing is the magnetic bearing according to any one of claims 1 to 11.

13. A compressor, characterized in that: It comprises a magnetic bearing, and the magnetic bearing is the magnetic bearing according to any one of claims 1 to 11.

14. An air conditioner, characterized in that: It comprises a magnetic bearing, and the magnetic bearing is the magnetic bearing according to any one of claims 1 to 11.

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