A motor rotor, a magnetic levitation device, a magnetic levitation motor, a turbine motor system

Abstract

A motor rotor, a magnetic suspension device, a magnetic suspension motor and a turbine motor system. The magnetic suspension device comprises a shell (1), a rotor (2), radial magnetic bearings (31, 32), axial magnetic bearings (41, 42) and a motor stator (5), wherein both sides of the rotor (2) are provided with stepped structures, and the stepped structures on both sides are asymmetric. The rotor can be applied to a magnetic suspension device, which can be applied to a magnetic suspension motor, a compressor and a pump. Through the design of the application, the stable operation of the magnetic suspension motor at high speed is realized, and the volume, mass and production cost of the magnetic suspension motor are reduced.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of magnetic levitation technology, and in particular to a magnetic levitation rotor, a magnetic levitation device, a magnetic levitation motor, and a turbine motor system. Background Technology

[0002] Traditional electric motors use contact bearings. The rotational speed of contact bearings is mainly limited by the temperature rise caused by friction and heat within the bearing. When the speed exceeds a certain limit, the bearing will stop rotating due to burn-out or other reasons. Therefore, it is difficult to further increase the speed of traditional motors. The industrial demand for high-speed motors is becoming increasingly urgent, and research on non-contact bearings, such as magnetic levitation motor technology, is receiving significant attention. Magnetic levitation motors can be applied to turbine motor systems (such as compressors, expanders, and pumps for transporting fluids).

[0003] Magnetic levitation motors use magnetic force to levitate and rotate the rotor, with no contact or friction between the rotor and the bearings. The rotational speed of the bearings is limited only by the rotor material. Therefore, given that the rotor material is fixed, only a well-designed structure can enable the magnetic levitation motor to operate at high speeds.

[0004] The rotor generates enormous centrifugal force when rotating at high speed. Since the centrifugal force is proportional to the rotor radius, the rotor's outer diameter should be as small as possible to reduce the centrifugal force. However, on the other hand, the rotor needs to provide sufficient magnetic area, so the rotor cannot be too small. This increases the overall design difficulty of the magnetic levitation rotor suspension device.

[0005] One existing design mounts the axial magnetic bearing and thrust disk at one end of the rotor, with the thrust disk protruding radially from the rotor. In this configuration, the maximum centrifugal force occurs at the maximum diameter of the thrust disk during rotor rotation. While this design provides magnetic area for the axial magnetic bearing, it neglects the influence of centrifugal force at high speeds, directly limiting the speed of the magnetic levitation motor to the diameter of the thrust disk. To reduce the maximum outer diameter of the rotor, another existing design incorporates symmetrical stepped designs at both ends of the rotor, mounting the axial magnetic bearing on either side of these stepped designs.

[0006] The existing symmetrical stepped rotor design does not take into account the unbalanced axial force characteristic of magnetic levitation motors during actual operation. The magnetic area of ​​this symmetrical stepped design is designed based on the parameters of the end with the greater axial force. The other end experiences less axial force, so not all of the magnetic force is utilized. If the symmetrical stepped rotor is designed with the side with less axial force, a small thrust plate needs to be installed on the side with greater force to balance the axial force. This would lead to a complex internal structure of the magnetic levitation motor and increase the number of components, making assembly and installation more difficult.

[0007] Therefore, the above design wastes excess materials, resulting in high manufacturing costs. Furthermore, the larger radial rotor diameter increases the overall size of the magnetic levitation motor, hindering its miniaturization and weight reduction. Moreover, the increased radial magnetic area leads to an increase in the axial thickness of the electromagnet, directly increasing the rotor's axial length, lowering the critical speed, and hindering the improvement of rotor speed. Summary of the Invention

[0008] In view of this, embodiments of the present invention provide a motor rotor, a magnetic levitation device, a magnetic levitation motor, a compressor, and a pump. At least one objective of the present invention is to enable the levitation rotor of the magnetic levitation device to meet the high-speed operating requirements, while simultaneously achieving miniaturization and weight reduction of the magnetic levitation motor.

[0009] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0010] At least one embodiment of the present invention provides a magnetic levitation device, including: a housing, and a rotor, a radial magnetic bearing, an axial magnetic bearing, and a motor stator disposed inside the housing; wherein, the rotor is provided with stepped structures on both sides of the central section of the motor stator, and the stepped structures on both sides of the rotor are asymmetrical structures.

[0011] For example, the diameter of the rotor portion between the stepped structures on both sides of the rotor is the same; the maximum step diameter of the stepped structure on one side of the rotor is the same as the diameter of the rotor portion between the stepped structures on both sides; and the maximum step diameter of the stepped structure on the other side of the rotor is greater than the diameter of the rotor portion between the stepped structures on both sides.

[0012] For example, the diameter of the stepped structure on both sides of the rotor is smaller closer to the rotor end on that side.

[0013] For example, in the stepped structures on both sides of the rotor, the first step depth on the side with the largest step diameter is greater than the first step depth on the other side; and the second step depth on the side with the largest step diameter is greater than the second step depth on the other side.

[0014] For example, the side with the larger step diameter on the rotor is located on the side opposite to the direction of the axial resultant force when the magnetic levitation motor using the magnetic levitation device is working normally.

[0015] For example, the resultant force refers to the sum of all forces in the axial direction when the magnetic levitation motor is working; and if the rotor's axial direction is not parallel to the horizontal plane, the resultant force also includes gravity.

[0016] For example, the stepped structures on both sides of the rotor have stepped surfaces, which are respectively opposite to the first axial magnetic bearing and the second axial magnetic bearing; and the first axial magnetic bearing and the second axial magnetic bearing generate axial attraction on the stepped surfaces of the rotor.

[0017] For example, the motor stator is located near the middle section of the rotor, and the axial magnetic bearing is located closer to the middle section of the rotor than the radial magnetic bearing.

[0018] For example, one end of the rotor is the output end.

[0019] For example, the other end of the rotor is also the output end.

[0020] For example, the asymmetrical stepped structure on both sides is provided with a groove structure.

[0021] At least one embodiment of the present invention also provides a magnetic levitation motor, including any of the magnetic levitation devices described above, and a working component disposed at at least one end of the rotor, the working component including an impeller.

[0022] For example, the magnetic levitation motor also includes an axial sensor disposed on one side of the rotor and radial sensors disposed on both sides of the rotor.

[0023] At least one embodiment of the present invention also provides a turbine motor system, including the magnetic levitation motor.

[0024] At least one embodiment of the present invention also provides a motor rotor, including a middle section and two end sections located outside the middle section, wherein the middle section has stepped structures on both sides, and the stepped structures on both sides are asymmetrical structures.

[0025] For example, the diameter of the middle section between the two stepped structures is the same; the maximum step diameter of the stepped structure on one side of the middle section is the same as the diameter of the middle section between the two stepped structures; and the maximum step diameter of the stepped structure on the other side of the middle section is greater than the diameter of the middle section between the two stepped structures.

[0026] For example, the diameter of the stepped structure on both sides of the middle section is smaller as it gets closer to the end of the end section on that side.

[0027] For example, in the stepped structure on both sides, the first step depth on the side with the largest step diameter is greater than the first step depth on the other side; and the second step depth on the side with the largest step diameter is greater than the second step depth on the other side.

[0028] For example, the stepped structures on both sides have stepped surfaces. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a magnetic levitation device provided in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of an asymmetric magnetic levitation rotor structure provided in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of an asymmetric magnetic levitation rotor structure provided in an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of an asymmetric magnetic levitation rotor structure provided in an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of an asymmetric magnetic levitation rotor structure provided in an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of an asymmetric magnetic levitation rotor structure provided in an embodiment of the present invention; and

[0035] Figure 7 This is a schematic diagram of the asymmetric magnetic levitation rotor structure in the magnetic levitation device provided in the embodiment of the present invention, which is in the form of a groove. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of the embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0037] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” “fourth,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “including” or “comprising” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, which may change accordingly when the absolute position of the described object changes.

[0038] like Figure 1As shown, an embodiment of the present invention provides a magnetic levitation device, including: a housing 1, a rotor 2 located inside the housing, a first radial magnetic bearing 31, a second radial magnetic bearing 32, a first axial magnetic bearing 41, a second axial magnetic bearing 42, and a motor stator 5. The radial magnetic bearings, axial magnetic bearings, and motor stator are part of the stator. When the magnetic levitation device is in operation, the rotor is suspended in the stator.

[0039] like Figure 1 As shown, most of the rotor 2, the first radial magnetic bearing 31, the second radial magnetic bearing 32, the first axial magnetic bearing 41, the second axial magnetic bearing 42, and the motor stator 5 are coaxially mounted inside the housing 1. For example, the rotor 2 can rotate around the direction of arrow A in the figure.

[0040] Continue as Figure 1 As shown, the stepped surfaces S1 and S2 on both sides of the rotor 2 are respectively opposite to the first axial magnetic bearing 41 and the second axial magnetic bearing 42. The first axial magnetic bearing 41 and the second axial magnetic bearing 42 generate axial attraction on the stepped surfaces S1 and S2 on the rotor 2, respectively, and the axial attraction is used to control the axial non-contact levitation of the rotor.

[0041] like Figure 2 As shown, for example, the rotor 2 of the present invention has asymmetrical stepped structures on both sides corresponding to the axial magnetic bearings. Each side of the stepped structure on both sides of the rotor 2 has two steps that cooperate with the axial magnetic bearings to generate axial attraction. The first step 21 of the left stepped step has a depth of a1, and the second step 22 has a depth of a2. The diameter of the first step 21, measured from its outermost point away from the rotor rotation axis A, is greater than the diameter d1 of the rotor portion between the two stepped structures. The first step 23 (or third step 23) of the right stepped step has a depth of b1, and the second step 24 (or fourth step 24) has a depth of b2. The diameter of the right first step 23, measured from its outermost point away from the rotor rotation axis A, is equal to the diameter d1 of the rotor portion between the two stepped structures.

[0042] Furthermore, the step depth on both sides of the asymmetric stepped structure of rotor 2 is related to the magnitude of the axial force on the motor during operation. In order to achieve miniaturization and weight reduction of the magnetic levitation motor, for example, the rotor diameter d1 is designed based on the side with smaller axial force, so the diameter of the first step 23 (or the third step 23) on the right side is equal to the rotor diameter d1 between the two stepped structures.

[0043] According to the inventor, in existing symmetrical stepped designs, the height of the steps must be designed according to the side with greater axial force; otherwise, the magnetic levitation motor cannot function properly. Therefore, the diameter between the two steps in existing designs is relatively large, requiring the selection of a larger diameter motor stator for installation, resulting in a radial dimension larger than that of the present invention. Furthermore, the symmetrical design of existing systems also dictates that the core thickness of the axial magnetic bearing is designed according to the side with greater axial force. This leads to an increase in the axial length of the rotor, reducing its critical speed and hindering the improvement of rotor speed.

[0044] Therefore, this invention achieves a reduction in rotor diameter compared to existing designs. Consequently, a smaller diameter motor stator can be selected and mounted on a smaller diameter rotor, thus realizing the miniaturization of the magnetic levitation motor.

[0045] Furthermore, for example, not only is the step diameter reduced on the side with smaller axial force, but the thickness of the axial magnetic bearing is also decreased. This reduces the rotor length and increases the rotor's critical speed (the speed at which the rotor vibrates strongly) without affecting the magnetic levitation performance. Furthermore, for example, since rotors used in magnetic levitation motors are often expensive, the design of this invention reduces the rotor diameter, decreases material usage, and achieves lightweighting of the magnetic levitation motor while controlling its cost.

[0046] For example, the depth a1 of the first step 21 on the left is greater than the depth b1 of the first step 23 on the right, and the depth a2 of the second step 22 on the left is greater than the depth b2 of the second step on the right.

[0047] It is understandable that the design of the asymmetrical stepped structure is related to the ideal axial force conditions under normal rotor operation. When the rotor is horizontal relative to the placement surface, such as... Figure 3 As shown, when the axial resultant force F is directed to the right during normal operation, the first step 21 and the second step 22 are designed on the left side of the rotor, and the third step 23 and the fourth step 24 are designed on the right side of the rotor. Conversely, as... Figure 4 As shown, when working normally, the axial resultant force F points to the left. Therefore, the first step 21 and the second step 22 are designed on the right side of the rotor, and the third step 23 and the fourth step 24 are designed on the left side of the rotor.

[0048] For example, the rotor is not necessarily horizontal to the placement surface; for example, ... Figure 5 As shown, when the rotor is not placed horizontally relative to the ground plane, the axial resultant force also includes gravity. During normal operation, the axial resultant force F points downwards, so a first step 21 and a second step 22 are designed on the upper side of the rotor, and a third step 23 and a fourth step 24 are designed on the lower side of the rotor. Conversely, for example, as... Figure 6As shown, when working normally, the axial resultant force F points upward. Therefore, the first step 21 and the second step 22 are designed on the lower side of the rotor, and the third step 23 and the fourth step 24 are designed on the upper side of the rotor.

[0049] However, the embodiments disclosed herein are not limited to the above-described placement and usage of the rotor. Accordingly, when the rotor is placed at other angles relative to the horizontal plane, the corresponding step design can also be adjusted according to the direction of the axial resultant force during normal operation of the rotor.

[0050] For example, in the asymmetrical stepped structure of rotor 2, the step diameter on both sides of rotor 2 is smaller the closer it is to the rotor ends. That is, the closer the step diameter on one side of rotor 2 is to the end of that side of the rotor, the smaller its step diameter. This design facilitates rotor machining and subsequent motor installation.

[0051] For example, see Figure 1 and 7 As shown, the motor stator 5 is installed near the middle section of the rotor 2. For example, the motor stator 5 is arranged around the rotor 2, or the rotor 2 is inserted into the stator 5. The first axial magnetic bearing 41 is closer to the center of the rotor 2 than the first radial magnetic bearing 31, and the second axial magnetic bearing 42 is closer to the center of the rotor than the second radial magnetic bearing 32. For example, to facilitate rotor machining and motor installation, the stepped diameter on both sides of the rotor 2 is smaller closer to the rotor ends. Therefore, to obtain a larger magnetic area, the axial magnetic bearings are installed near the rotor center with relatively larger diameters, thereby obtaining a larger magnetic area.

[0052] For example, such as Figure 7 As shown, in order to prevent magnetic leakage, groove structures G1 and G2 can be set near the asymmetrical design steps on both sides.

[0053] For example, embodiments of the present invention also provide a magnetic levitation motor, the magnetic levitation motor including the magnetic levitation device with an asymmetrical stepped structure on both sides of the rotor as described in any of the above embodiments.

[0054] The magnetic levitation motor can have working components installed at both ends of the rotor 2, or it can have working components installed at only one end. For example, taking a two-stage centrifugal air compressor as an example, a two-stage centrifugal compressor using the magnetic levitation motor designed in this invention can have working components installed at both ends of the rotor. For example, taking a one-stage centrifugal compressor or centrifugal pump as an example, a working component can be installed on only one side, and no working component can be installed on the other side. For example, the working component can be an impeller.

[0055] The magnetic levitation motor is equipped with axial and radial sensors. For example, the radial sensors can be installed on both sides of the rotor and fitted with radial magnetic bearings. For example, the axial sensors can be installed only on the side of the rotor with the larger stepped diameter, because the magnetic force of the axial magnetic bearing on the side with the larger stepped diameter is greater, and the accuracy requirement for axial displacement is higher. However, the embodiments of the present invention are not limited to these.

[0056] Magnetic levitation motors can achieve a wider speed range through the aforementioned magnetic levitation device, and can also achieve lightweight and miniaturization, further reducing production and manufacturing costs.

[0057] The magnetic levitation motor can be applied in turbine motor systems (such as compressors, expanders, pumps for conveying fluids, etc.).

[0058] Embodiments of the present invention also provide a turbine motor system, which includes the magnetic levitation motor described above.

[0059] It should be noted that, without conflict, those skilled in the art can combine the relevant technical features or examples in the above examples according to the actual situation to achieve the corresponding technical effects. Specific details of the various combinations are not elaborated here.

[0060] The above description is merely an example embodiment of the present invention and is not intended to limit the present invention in any way. Any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A magnetic levitation device, comprising: Housing, rotor disposed inside the housing, radial magnetic bearing, axial magnetic bearing, and motor stator; The rotor has stepped structures on both sides of the central section relative to the motor stator, and the stepped structures on both sides of the rotor are asymmetrical. The axial magnetic bearing includes a first axial magnetic bearing and a second axial magnetic bearing. The stepped structures on both sides of the rotor have stepped surfaces, which are respectively opposite to the first axial magnetic bearing and the second axial magnetic bearing. The first axial magnetic bearing and the second axial magnetic bearing generate axial attraction on the stepped surfaces of the rotor. The rotor portions between the stepped structures on both sides of the rotor have the same diameter. The maximum step diameter of the stepped structure on one side of the rotor is the same as the diameter of the rotor portion between the stepped structures on both sides; and The maximum step diameter of the stepped structure on the other side of the rotor is greater than the diameter of the rotor between the stepped structures on both sides. Among the stepped structures on both sides of the rotor, the first step depth on the side with the largest step diameter is greater than the first step depth on the other side; and the second step depth on the side with the largest step diameter is greater than the second step depth on the other side.

2. The magnetic levitation device according to claim 1, wherein, The diameter of the stepped structures on both sides of the rotor is smaller as it gets closer to the rotor end on that side.

3. The magnetic levitation device according to claim 1, wherein, The side with the larger step diameter on the rotor is positioned opposite to the direction of the axial resultant force when the magnetic levitation motor using the magnetic levitation device is operating normally.

4. The magnetic levitation device according to claim 3, wherein, The resultant force refers to the sum of all forces in the axial direction when the magnetic levitation motor is working; and if the rotor's axial direction is not parallel to the horizontal plane, the resultant force also includes gravity.

5. The magnetic levitation device according to claim 1, wherein, The motor stator is located near the middle section of the rotor, and the axial magnetic bearing is located closer to the middle section of the rotor than the radial magnetic bearing.

6. The magnetic levitation device according to claim 1, wherein, One end of the rotor is the output end.

7. The magnetic levitation device according to claim 6, wherein, The other end of the rotor is also the output end.

8. The magnetic levitation device according to any one of claims 1 to 7, wherein, The asymmetrical stepped structure on both sides is provided with a groove structure.

9. A magnetic levitation motor, comprising a magnetic levitation device according to any one of claims 1 to 8, and a working component disposed at at least one end of the rotor, the working component comprising an impeller.

10. The magnetic levitation motor according to claim 9 further includes an axial sensor disposed on one side of the rotor and radial sensors disposed on both sides of the rotor.

11. A turbine motor system comprising the magnetic levitation motor of claim 10.

12. An electric motor rotor, comprising a middle section and two end sections respectively located outside the middle section, wherein, The middle section has stepped structures on both sides, and the stepped structures on both sides are asymmetrical; the stepped structures on both sides have stepped surfaces for generating axial attraction relative to the axial magnetic bearing. The diameter of the middle section between the two stepped structures is the same. The maximum step diameter of the stepped structure on one side of the middle section is the same as the diameter of the middle section between the stepped structures on both sides; and The maximum step diameter of the stepped structure on the other side of the middle section is greater than the diameter of the middle section between the stepped structures on both sides. Among the stepped structures on both sides, the first step depth on the side with the largest step diameter is greater than the first step depth on the other side; and the second step depth on the side with the largest step diameter is greater than the second step depth on the other side.

13. The rotor according to claim 12, wherein, The diameter of the stepped structure on both sides of the middle section is smaller as it gets closer to the end of the end section on that side.

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