A three-degree-of-freedom magnetic levitation bearing structure and a compressor

Abstract

This invention provides a three-degree-of-freedom magnetic levitation bearing structure and a compressor. The three-degree-of-freedom magnetic levitation bearing structure includes: a thrust disk, a three-degree-of-freedom bearing axial core, and a magnetic ring. The thrust disk is disposed at the stepped surface of the rotor. At least a portion of the structure of the three-degree-of-freedom bearing axial core is located at one axial end of the thrust disk and can abut against the thrust disk. At least a portion of the structure of the magnetic ring is located at the other axial end of the thrust disk and can abut against the thrust disk. Along the axial direction of the rotor, the area of ​​the three-degree-of-freedom bearing axial core relative to the thrust disk along the axial direction is larger than the area of ​​the magnetic ring relative to the thrust disk along the axial direction. According to this invention, axial force control can be achieved with a smaller axial control current, reducing losses and effectively solving the problem of large axial current and significant losses in existing three-degree-of-freedom magnetic levitation bearings.

Description

Technical Field

[0001] This utility model relates to the field of compressor technology, specifically to a three-degree-of-freedom magnetic levitation bearing structure and a compressor. Background Technology

[0002] Magnetic levitation bearings, with their numerous advantages such as non-contact operation, wear-free operation, high speed, high precision, and no need for lubrication or sealing, have become a high-tech product integrating electromagnetics, electronic technology, control engineering, signal processing, and mechanics.

[0003] Magnetic bearings are mainly classified into three types: active, passive, and hybrid. Active magnetic bearings offer high stiffness and precise control, but require a larger volume and consume more power per unit load. Passive magnetic bearings rely on the attractive or repulsive forces between magnetic materials to levitate the rotor, resulting in lower stiffness and damping. Hybrid magnetic bearings use permanent magnets to provide a bias magnetic field, replacing the static bias magnetic field generated by electromagnets in active magnetic bearings. This reduces the ampere-turns of the control windings, shrinks the bearing size, and increases the load-bearing capacity. Hybrid magnetic bearings offer significant advantages in applications with stringent requirements for size and power consumption. Magnetic bearings are widely used in high-speed and ultra-high-speed applications. Therefore, the integration and miniaturization of magnetic levitation systems, as well as improving the stability and reliability of control systems, will be key research areas in the future.

[0004] In existing three-degree-of-freedom bearing solutions, the axial bearing section is designed with symmetrical force output. When the rotor is subjected to axial forces of the same magnitude in both directions, the axial current required for control is equal in magnitude but opposite in direction. Therefore, when the rotor is continuously subjected to axial force on one side under operating conditions, the axial current must be maintained. If the required axial current is large, it will cause significant losses.

[0005] Because existing three-degree-of-freedom magnetic levitation bearings have a symmetrical force output design in the axial bearing section, resulting in a large axial current and causing significant losses, this invention researches and designs a three-degree-of-freedom magnetic levitation bearing structure and a compressor. Utility Model Content

[0006] Therefore, the technical problem to be solved by this utility model is to overcome the defect of the existing three-degree-of-freedom magnetic levitation bearing, which has a large axial current due to the symmetrical force output design of the axial bearing part, resulting in a large loss. Thus, a three-degree-of-freedom magnetic levitation bearing structure and compressor are provided.

[0007] To address the aforementioned problems, this utility model provides a three-degree-of-freedom magnetic levitation bearing structure, comprising:

[0008] The rotor comprises a thrust disk, a three-degree-of-freedom bearing axial core, and a magnetic ring. The thrust disk is disposed on the stepped surface of the rotor. At least a portion of the structure of the three-degree-of-freedom bearing axial core is located at one axial end of the thrust disk and can abut against the thrust disk. At least a portion of the structure of the magnetic ring is located at the other axial end of the thrust disk and can abut against the thrust disk. Along the axial direction of the rotor, the area of ​​the three-degree-of-freedom bearing axial core relative to the thrust disk along the axial direction is larger than the area of ​​the magnetic ring relative to the thrust disk along the axial direction.

[0009] In some implementations...

[0010] In the longitudinal section plane passing through the axis of the rotor, along the radial direction of the rotor, the radial length of the axial core of the three-degree-of-freedom bearing relative to the thrust disk is longer than the radial length of the magnetic ring relative to the thrust disk; thus, the contact area between the axial core of the three-degree-of-freedom bearing and the thrust disk along the axial direction is larger than the contact area between the magnetic ring and the thrust disk along the axial direction.

[0011] In some implementations...

[0012] The thrust disk along the radial direction of the rotor includes a first segment and a second segment that are in contact. The first segment is opposite to the stepped surface of the rotor along the axial direction, and the second segment is not opposite to the stepped surface along the axial direction. The second segment is located on the radial outer periphery of the first segment along the radial direction of the rotor.

[0013] The radial inner end of the axial core of the three-degree-of-freedom bearing is opposite to the first segment along the axial direction of the rotor, and the radial inner end of the magnetic ring is opposite to the second segment along the axial direction of the rotor.

[0014] In some implementations...

[0015] The rotor includes a first shaft segment and a second shaft segment, the outer diameter of the first shaft segment is smaller than the outer diameter of the second shaft segment, the first shaft segment and the second shaft segment are axially connected to form the stepped surface at the connection point, the stepped surface being at least a portion of the axial end face of the second shaft segment;

[0016] The radial inner end of the axial core of the three-degree-of-freedom bearing is opposite to the first shaft segment along the radial direction of the rotor. The radial inner end of the axial core of the three-degree-of-freedom bearing and the first shaft segment have a first gap along the radial direction. The radial length of the first gap is smaller than the radial length of the stepped surface along the radial direction of the rotor.

[0017] In some implementations...

[0018] The inner radial end of the magnetic ring is opposite to the second shaft segment along the radial direction of the rotor, and the inner radial end of the magnetic ring and the second shaft segment have a second gap along the radial direction; along the radial direction of the rotor, the radial dimension of the first gap is smaller than the radial dimension of the second gap.

[0019] In some implementations...

[0020] It also includes an axial winding and a radial winding. The axial winding is located on the radial outer periphery of the thrust disk and is spaced at a predetermined distance from the thrust disk. The radial winding is located on the axial side of the magnetic ring away from the thrust disk, such that the magnetic ring is located between the thrust disk and the radial winding, and along the axial direction of the rotor. At least a portion of the structure of the axial winding is axially opposite to at least a portion of the structure of the radial winding. The radial outer end of the thrust disk is opposite to the radial inner end of the radial winding in the axial direction, or the radial outer end of the thrust disk is not opposite to the radial inner end of the radial winding in the axial direction, and is located at a position opposite to the radial inner side of the radial winding.

[0021] In some implementations...

[0022] At least a portion of the structure of the axial core of the three-degree-of-freedom bearing is located on the radial outer periphery of the axial winding. The radial inner periphery of at least a portion of the structure of the axial core forms a first cavity. The axial winding and the thrust disk are disposed in the first cavity. The bearing also includes a radial core of the three-degree-of-freedom bearing. The radial core has a second cavity located on the radial inner periphery of a portion of its structure. At least a portion of the structure of the radial winding is located in the second cavity. The radial inner wall of the first cavity and the radial inner wall of the second cavity are opposite to each other along the axial direction of the rotor, or the radial inner side of the radial inner wall of the first cavity and the radial inner wall of the second cavity are opposite to each other along the axial direction of the rotor.

[0023] In some implementations...

[0024] The axial core of the three-degree-of-freedom bearing is located at one axial end of the magnetic ring and is in contact with the end face of the magnetic ring at one axial end. The radial core of the three-degree-of-freedom bearing is located at the other axial end of the magnetic ring and is in contact with the end face of the other axial end of the magnetic ring. The radial thickness of a portion of the structure of the axial core of the three-degree-of-freedom bearing on the outer periphery of the first cavity is not less than the radial thickness of a portion of the structure of the radial core of the three-degree-of-freedom bearing on the outer periphery of the second cavity.

[0025] In some implementations...

[0026] It also includes a three-degree-of-freedom bearing radial housing, wherein a portion of the three-degree-of-freedom bearing radial housing is located on the outer periphery of the three-degree-of-freedom bearing radial core, a portion of the three-degree-of-freedom bearing radial housing is located on the outer periphery of the magnetic guide ring, and a portion of the three-degree-of-freedom bearing radial housing is located on the outer periphery of a portion of the three-degree-of-freedom bearing axial core, such that the three-degree-of-freedom bearing radial core, the magnetic guide ring, and the three-degree-of-freedom bearing axial core are respectively fixed to the three-degree-of-freedom bearing radial housing.

[0027] This utility model also provides a compressor, which includes the aforementioned asymmetric three-degree-of-freedom magnetic levitation bearing structure, and also includes a rotor, the rotor being located on the inner circumference of the thrust disk, the axial iron core of the three-degree-of-freedom bearing and the magnetic ring.

[0028] In some implementations...

[0029] It also includes a motor stator, the rotor including at least one stepped surface on one side of the motor stator axial direction and at least one stepped surface on the other side of the motor stator axial direction, the stepped surfaces on both sides of the motor stator axial direction are symmetrically arranged with respect to the motor stator; and the three-degree-of-freedom magnetic levitation bearing structure is provided at the stepped surface on one side of the motor stator axial direction, and the three-degree-of-freedom magnetic levitation bearing structure is also provided at the stepped surface on the other side of the motor stator axial direction.

[0030] The three-degree-of-freedom magnetic levitation bearing structure and compressor provided by this utility model have the following beneficial effects:

[0031] 1. This invention forms an axially asymmetric three-degree-of-freedom magnetic levitation bearing structure by making the area of ​​the axial core of the three-degree-of-freedom bearing relative to the thrust disk along the axial direction larger than the area of ​​the magnetic ring relative to the thrust disk along the axial direction. This results in different output capacities on both sides of the thrust disk along the axial direction. When the axial coil carries currents of the same magnitude but opposite directions, the axial output on one side (axial core side) will be significantly greater than the axial output on the other side (magnetic ring side). When applied to rotors under conditions where one side of the axial direction is continuously stressed, axial force control can be achieved with a smaller axial control current, reducing losses. This invention also effectively reduces heat generation by reducing the axial control current, improving the operating performance and lifespan of the magnetic levitation bearing. It effectively solves the problem in existing three-degree-of-freedom magnetic levitation bearings where the symmetrical output design of the axial bearing section leads to a large axial current and significant losses.

[0032] 2. The heat generation of the high-speed permanent magnet motor rotor of this invention mainly comes from air friction loss. Among the losses of various parts of the rotor, the thrust disk generates the most losses. The thrust disk radius is a crucial parameter affecting the air friction loss of the thrust disk, as it is directly proportional to the difference between the fifth power of its outer diameter and the fifth power of its inner diameter. Existing three-degree-of-freedom bearings employ an axially symmetrical design, requiring a larger outer diameter of the thrust disk and resulting in greater air friction loss in this section. In this invention, the asymmetrical three-degree-of-freedom bearing layout, combined with the stepped rotor structure, achieves the same unilateral axial output force with a smaller outer diameter of the thrust disk, significantly reducing the outer diameter of the thrust disk and thus lowering the rotor's air friction loss.

[0033] 3. In designing the rotor of a high-speed permanent magnet motor, the rotor's fixed-frequency design is a crucial aspect of the overall shaft design. Without skipping steps, the maximum operating speed of the high-speed rotor should be lower than its first-order bending frequency, and a certain isolation margin must be maintained to ensure minimal vibration and prevent resonance during high-speed operation. Therefore, for the design of a high-speed permanent magnet motor rotor, it is desirable that its first-order bending frequency be sufficiently high to meet design requirements. A larger thrust disk outer diameter increases the rotor's gyroscopic effect and decreases the first-order bending frequency, and vice versa. Figure 1-3 As can be seen from the comparison with 4-8, the solution of this utility model can significantly reduce the outer diameter of the thrust disk under similar design conditions, so that the rotor can obtain better dynamic characteristics.

[0034] 4. The bearings of this utility model can also be symmetrically arranged on both sides of the rotor, which can enhance the axial output performance of the rotor, while reducing the axial control current to reduce losses and heat generation. This effectively solves the problem that the existing three-degree-of-freedom magnetic levitation bearings have a large axial current due to the symmetrical output design of the axial bearing part, which causes large losses. Attached Figure Description

[0035] Figure 1 This is a simplified structural diagram of a magnetic levitation compressor based on existing technology.

[0036] Figure 2 This is a longitudinal sectional view of a magnetic levitation compressor based on existing technology.

[0037] Figure 3 yes Figure 2 An enlarged structural diagram of the magnetic levitation bearing section in the image;

[0038] Figure 4 This is a simplified overall structural diagram of the magnetic levitation compressor of this utility model (Scheme 1);

[0039] Figure 5 yes Figure 4 A longitudinal section diagram of the magnetic levitation compressor;

[0040] Figure 6 This is a simplified overall structural diagram of the magnetic levitation compressor of this utility model (Scheme 2);

[0041] Figure 7 yes Figure 6 A longitudinal section diagram of the magnetic levitation compressor;

[0042] Figure 8 yes Figure 5 or Figure 7 An enlarged structural diagram of the three-degree-of-freedom magnetic levitation bearing section.

[0043] Figure 1-3 The reference numerals in the (prior art) figures are indicated as follows:

[0044] 1. Rotor; 2. Thrust disc; 3. Axial core of three-degree-of-freedom bearing; 4. Axial winding; 5. Radial housing of three-degree-of-freedom bearing; 6. Compressor cylinder; 7. Magnetic ring; 8. Radial core of three-degree-of-freedom bearing; 9. Radial winding; 10. Motor stator; 11. Radial winding two; 12. Radial bearing core; 13. Radial bearing housing; 100. Three-degree-of-freedom magnetic levitation bearing; 200. Radial bearing.

[0045] Figure 4-8 The reference numerals in the drawings of (this utility model) are as follows:

[0046] 1. Rotor; 2. Thrust disc; 3. Axial core of three-degree-of-freedom bearing; 4. Axial winding; 5. Radial housing of three-degree-of-freedom bearing; 6. Compressor cylinder; 7. Magnetic ring; 8. Radial core of three-degree-of-freedom bearing; 9. Radial winding; 10. Motor stator; 11. Radial winding two; 12. Radial bearing core; 13. Radial bearing housing; 14. Stepped surface; 15. First shaft section; 16. Second shaft section; 17. First cavity; 18. Second cavity; 100. Three-degree-of-freedom magnetic levitation bearing structure; 200. Radial bearing. Detailed Implementation

[0047] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0048] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0049] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0050] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0051] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0052] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0053] like Figure 4-8 As shown, this utility model provides a three-degree-of-freedom magnetic levitation bearing structure, which includes:

[0054] The rotor 1 comprises a thrust disk 2, a three-degree-of-freedom bearing axial core 3, and a magnetic ring 7. The thrust disk 2 is disposed at the stepped surface 14 of the rotor 1. At least a portion of the structure of the three-degree-of-freedom bearing axial core 3 is located at one axial end of the thrust disk 2 and can abut against the thrust disk 2. At least a portion of the structure of the magnetic ring 7 is located at the other axial end of the thrust disk 2 and can abut against the thrust disk 2. Along the axial direction of the rotor 1, the area of ​​the three-degree-of-freedom bearing axial core 3 relative to the thrust disk 2 along the axial direction is larger than the area of ​​the magnetic ring 7 relative to the thrust disk 2 along the axial direction.

[0055] This invention forms an axially asymmetric three-degree-of-freedom magnetic levitation bearing structure by making the area of ​​the axial core of the three-degree-of-freedom bearing relative to the thrust disk along the axial direction larger than the area of ​​the magnetic ring relative to the thrust disk along the axial direction. This results in different output capacities on both sides of the thrust disk along the axial direction. When the axial coil carries currents of the same magnitude but opposite directions, the axial output on one side (axial core side) will be significantly greater than the axial output on the other side (magnetic ring side). When applied to rotors under conditions where one side of the axial direction is continuously stressed, axial force control can be achieved with a smaller axial control current, reducing losses. This invention also effectively reduces heat generation by reducing the axial control current, improving the operating performance and lifespan of the magnetic levitation bearing. It effectively solves the problem in existing three-degree-of-freedom magnetic levitation bearings where the symmetrical output design of the axial bearing section leads to a large axial current and significant losses.

[0056] The heat generation of the high-speed permanent magnet motor rotor in this invention mainly comes from air friction loss. Among the losses of various parts of the rotor, the thrust disk generates the most losses. The thrust disk radius is a crucial parameter affecting the air friction loss of the thrust disk, as it is directly proportional to the difference between the fifth power of its outer diameter and the fifth power of its inner diameter. Existing three-degree-of-freedom bearings employ an axially symmetrical design, requiring a larger outer diameter of the thrust disk and resulting in greater air friction loss in this section. In this invention, the asymmetrical three-degree-of-freedom bearing layout, combined with the stepped rotor structure, achieves the same unilateral axial output force with a smaller outer diameter of the thrust disk, significantly reducing the outer diameter of the thrust disk and thus lowering the rotor's air friction loss.

[0057] In designing a high-speed permanent magnet motor rotor, the rotor's fixed-frequency design is a crucial aspect of the overall shaft design. Without skipping steps, the rotor's maximum operating speed should be lower than its first-order bending frequency, and a certain isolation margin is required to ensure minimal vibration and prevent resonance during high-speed operation. Therefore, for the design of a high-speed permanent magnet motor rotor, a sufficiently high first-order bending frequency is desirable to meet design requirements. Increasing the outer diameter of the thrust disk amplifies the rotor's gyroscopic effect, lowering the first-order bending frequency, and vice versa. Figure 1-3 As can be seen from the comparison with 4-8, the solution of this utility model can significantly reduce the outer diameter of the thrust disk under similar design conditions, so that the rotor can obtain better dynamic characteristics.

[0058] In some implementations...

[0059] In the longitudinal section plane passing through the axis of the rotor 1, along the radial direction of the rotor 1, the radial length of the three-degree-of-freedom bearing axial core 3 relative to the thrust disk 2 is longer than the radial length of the magnetic ring 7 relative to the thrust disk 2; thus, the contact area of ​​the three-degree-of-freedom bearing axial core 3 and the thrust disk 2 along the axial direction is larger than the contact area of ​​the magnetic ring 7 and the thrust disk 2 along the axial direction.

[0060] This is a further optimized structural form of the three-degree-of-freedom bearing axial core, thrust disk, and magnetic ring of this utility model. Specifically, the axial length (radial) of the three-degree-of-freedom bearing axial core relative to the thrust disk is longer than the axial length (radial) of the magnetic ring relative to the thrust disk. This results in a larger contact area between the three-degree-of-freedom bearing axial core and the thrust disk along the axial direction compared to the contact area between the magnetic ring and the thrust disk along the axial direction. This forms an axially asymmetric three-degree-of-freedom magnetic levitation bearing structure. The axially asymmetric three-degree-of-freedom bearing can increase the magnetic pole area between the thrust disk and the axial bearing on one side, making the output force on the axial core side significantly greater than the axial output force on the magnetic ring side. Axial force control can be achieved with a smaller axial control current, achieving the output level of existing solutions and reducing losses.

[0061] In some implementations...

[0062] The thrust disk 2 along the radial direction of the rotor 1 includes a first segment and a second segment that are connected. The first segment is opposite to the stepped surface 14 of the rotor 1 along the axial direction, and the second segment is not opposite to the stepped surface 14 along the axial direction. The second segment is located on the radial outer periphery of the first segment along the radial direction of the rotor 1.

[0063] The radial inner end of the axial core 3 of the three-degree-of-freedom bearing is opposite to the first segment along the axial direction of the rotor 1, and the radial inner end of the magnetic ring 7 is opposite to the second segment along the axial direction of the rotor 1.

[0064] This invention relates to the relative relationships between the axial core, magnetic ring, and thrust disk of a three-degree-of-freedom bearing. Specifically, the radially inner end of the axial core is opposite to the first section along the rotor's axial direction, and the radially inner end of the magnetic ring is opposite to the second section along the rotor's axial direction. This results in the axial core's radially inner extension being longer than the magnetic ring's radially inner extension. Consequently, the magnetic pole area on one side of the axial core and thrust disk is larger than that on the magnetic ring side, leading to a significantly greater axial output force on the core side compared to the magnetic ring side. This allows for axial force control with a smaller axial control current, achieving the same output level as existing solutions while reducing losses. Furthermore, by using a smaller thrust disk outer diameter, the same axial output force on one side is achieved, significantly reducing the thrust disk's outer diameter and thus lowering rotor air friction losses. Additionally, by reducing the thrust disk's outer diameter, the first-order bending frequency of the rotor can be increased while keeping other design parameters constant, resulting in superior dynamic characteristics.

[0065] In some implementations...

[0066] The rotor 1 includes a first shaft segment 15 and a second shaft segment 16. The outer diameter of the first shaft segment 15 is smaller than the outer diameter of the second shaft segment 16. The first shaft segment 15 and the second shaft segment 16 are axially connected to form the stepped surface 14 at the connection point. The stepped surface 14 is at least a portion of the axial end face of the second shaft segment 16.

[0067] The radial inner end of the axial core 3 of the three-degree-of-freedom bearing is opposite to the first shaft segment 15 along the radial direction of the rotor 1. The radial inner end of the axial core 3 of the three-degree-of-freedom bearing and the first shaft segment 15 have a first gap along the radial direction. The radial length of the first gap is smaller than the radial length of the stepped surface 14 along the radial direction of the rotor 1.

[0068] This is a preferred structural form between the rotor and the axial core of the three-degree-of-freedom bearing of this utility model. Specifically, the radially inner end of the axial core of the three-degree-of-freedom bearing is opposite to the first shaft segment along the radial direction of the rotor. The radially inner end of the axial core of the three-degree-of-freedom bearing and the first shaft segment have a first gap along the radial direction. The radial length of the first gap is smaller than the radial length of the stepped surface, allowing the radially inner end of the axial core to extend beyond the outer circumference of the second shaft segment of the rotor. This further increases the magnetic pole area on one side of the three-degree-of-freedom bearing axial core and the thrust disk, resulting in a significantly greater axial output force on the axial core side than on the magnetic ring side. Axial force control can be achieved with a smaller axial control current, reaching the output level of existing solutions and reducing losses. Simultaneously, achieving the same axial output force on one side using a smaller thrust disk outer diameter greatly reduces the outer diameter of the thrust disk, thereby reducing the rotor's air friction loss. Furthermore, by reducing the outer diameter of the rotor thrust disk, the first-order bending frequency of the rotor can be increased while keeping other design parameters unchanged, resulting in superior dynamic characteristics.

[0069] In some implementations...

[0070] The inner radial end of the magnetic ring 7 is opposite to the second shaft segment 16 along the radial direction of the rotor 1, and the inner radial end of the magnetic ring 7 and the second shaft segment 16 have a second gap along the radial direction; along the radial direction of the rotor 1, the radial dimension of the first gap is smaller than the radial dimension of the second gap.

[0071] This is a further optimized structural relationship between the magnetic guide ring and the axial core of the bearing in this utility model. Specifically, the radial dimension of the first gap between the radial inner end of the axial core and the first shaft segment is set to be greater than the radial dimension of the second gap between the radial inner end of the magnetic guide ring and the second shaft segment. This further increases the axial core side output force, making it significantly greater than the magnetic guide ring side output force. Axial force control can be achieved with a smaller axial control current, reaching the output level of existing solutions and reducing losses. Simultaneously, the same unilateral axial output force is achieved using a smaller thrust disk outer diameter, greatly reducing the outer diameter of the thrust disk and thus reducing rotor air friction losses. Furthermore, by reducing the outer diameter of the rotor thrust disk, the first-order bending frequency of the rotor can be increased while other design parameters remain unchanged, resulting in superior dynamic characteristics.

[0072] In some implementations...

[0073] It also includes an axial winding 4 and a radial winding 9. The axial winding 4 is located on the radial outer periphery of the thrust disk 2 and is spaced at a predetermined distance from the thrust disk 2. The radial winding 9 is located on the axial side of the magnetic ring 7 away from the thrust disk 2, such that the magnetic ring 7 is located between the thrust disk 2 and the radial winding 9, and along the axial direction of the rotor 1. At least a portion of the structure of the axial winding 4 is axially opposite to at least a portion of the structure of the radial winding 9. The radial outer end of the thrust disk 2 is opposite to the radial inner end of the radial winding 9 in the axial direction, or the radial outer end of the thrust disk 2 is not opposite to the radial inner end of the radial winding 9 in the axial direction, and is located at a position opposite to the radial inner side of the radial winding 9.

[0074] This is a further preferred structural form of the three-degree-of-freedom magnetic levitation bearing of this invention. Specifically, at least a portion of the axial winding and at least a portion of the radial winding are axially opposite each other. Compared to the prior art where the axial winding is located axially on the outer axis of the radial winding, the axial winding of this invention is moved radially inward. This is due to the reduction in the radial dimension of the thrust disk. The reduction in the radial dimension of the thrust disk comes from the increase in the single-sided contact area between the bearing axial core and the thrust disk. Therefore, it is possible to increase the contact area between the bearing axial core and the thrust disk while still reducing the radial dimension of the thrust disk. By reducing air friction loss, this invention, through the aforementioned structure, allows the outer radial end of the thrust disk to be opposite to the inner radial end of the radial winding in the axial direction, or the outer radial end of the thrust disk to be opposite to the inner radial end of the radial winding in the axial direction, and located at a position opposite to the inner radial side of the radial winding. This further reduces the radial dimension of the thrust disk, further reduces the air friction loss of the rotor, and achieves the same unilateral axial output force with a smaller thrust disk outer diameter. At the same time, axial force control can be achieved with a smaller axial control current, reducing losses.

[0075] The implementation scheme and axial magnetic circuit of this utility model's three-degree-of-freedom bearing are as follows: Figure 4-8 As shown, the three-degree-of-freedom bearing consists of an axial core 3, an axial winding 4, a radial housing 5, a compressor cylinder 6, a magnetic ring 7, a radial core 8, and a radial winding 9. It achieves an integrated design by sharing a portion of the axial and radial magnetic circuits, saving space. The various parts of the three-degree-of-freedom bearing are mainly assembled using heat fittings, screws, and adhesive. The radial core and housing are assembled with an interference fit using heat fittings; the radial core is assembled with the magnets and magnetic ring using adhesive and screws; and the remaining parts are assembled with clearance fits using screws. Figure 8This is a detailed diagram of the assembly position of the existing three-degree-of-freedom bearing. The three-degree-of-freedom bearing is assembled with the compressor body 6 by fixing with screws and using clearance fit. During assembly, the radial part of the three-degree-of-freedom bearing (radial housing 5, magnetic ring 7, radial core 8, and radial winding 9) is first assembled onto the compressor body. Then, the rotor 1 is assembled. After the rotor is inserted into the shaft, the axial part of the three-degree-of-freedom bearing (axial core 3 and axial winding 4) is assembled. The thrust disk 2 is press-fitted onto the step of the rotor 1 by heat fitting. The part that overlaps with the axial core 3 and magnetic ring 7 of the three-degree-of-freedom bearing forms a closed magnetic circuit. Axial control is achieved by passing axial control currents of different directions and magnitudes through the axial winding 4.

[0076] The implementation scheme and axial magnetic circuit of the three-degree-of-freedom bearing of this utility model are as follows: Figure 8 As shown, by reducing the gap between the axial core 3 of the three-degree-of-freedom bearing and the rotor 1, the overlap area between the axial core 3 and the thrust disk 2 is increased. Simultaneously, the outer diameter of the thrust disk 2 is reduced. Combined with the stepped structure of the rotor 1, the overlap area between the magnetic ring 7 and the thrust disk 2 is reduced while ensuring that the overlap area between the axial core 3 and the thrust disk 2 is greater than that of existing three-degree-of-freedom bearing implementations, thus achieving an axially asymmetrical structural design. In this utility model's three-degree-of-freedom bearing implementation, the axial output of the three-degree-of-freedom bearing in the directions on both sides of the thrust disk 2 is no longer symmetrical. When the same axial control current is applied as in the existing three-degree-of-freedom bearing implementation, the output on one side of the axial core 3 will be higher than in the existing scheme, while the output on the one side of the magnetic ring 7 will be lower.

[0077] In some implementations...

[0078] At least a portion of the structure of the three-degree-of-freedom bearing axial core 3 is located on the radial outer periphery of the axial winding 4. The radial inner periphery of at least a portion of the structure of the three-degree-of-freedom bearing axial core 3 forms a first cavity 17. The axial winding 4 and the thrust disk 2 are disposed in the first cavity 17. The first cavity 17 also includes a three-degree-of-freedom bearing radial core 8. The three-degree-of-freedom bearing radial core 8 has a second cavity 18 located on the radial inner periphery of a portion of its structure. At least a portion of the structure of the radial winding 9 is located in the second cavity 18. The radial inner periphery wall of the first cavity 17 and the radial inner periphery wall of the second cavity 18 are opposite each other along the axial direction of the rotor 1, or the radial inner side of the radial inner periphery wall of the first cavity 17 and the radial inner periphery wall of the second cavity 18 are opposite each other along the axial direction of the rotor 1.

[0079] This is the preferred positional relationship between the axial core and radial core of the three-degree-of-freedom bearing of this utility model. The axial core includes a first cavity for accommodating the axial winding and the thrust disk, and the radial core includes a second cavity for accommodating the radial winding. Furthermore, the radial inner circumferential wall of the first cavity and the radial inner circumferential wall of the second cavity are aligned axially with each other along the rotor, or the radial inner circumferential wall of the first cavity and the radial inner circumferential wall of the second cavity are aligned radially inward along the rotor's axial direction. This can further reduce the radial outer circumferential position of the axial winding, further shorten the radial dimension of the thrust disk, further reduce the air friction loss of the rotor, achieve the same unilateral axial output force with a smaller thrust disk outer diameter, and also achieve axial force control with a smaller axial control current, reducing losses.

[0080] In some implementations...

[0081] The axial core 3 of the three-degree-of-freedom bearing is located at one axial end of the magnetic ring 7 and is in contact with the end face of the axial end of the magnetic ring 7. The radial core 8 of the three-degree-of-freedom bearing is located at the other axial end of the magnetic ring 7 and is in contact with the end face of the other axial end of the magnetic ring 7. The radial thickness of a portion of the structure of the axial core 3 of the three-degree-of-freedom bearing on the outer periphery of the first cavity 17 is not less than the radial thickness of a portion of the structure of the radial core 8 of the three-degree-of-freedom bearing on the outer periphery of the second cavity 18.

[0082] This invention further shortens the radial inner wall of the first cavity by using a portion of the radial thickness of the three-degree-of-freedom bearing axial core structure on the outer periphery of the first cavity, which is not less than the radial thickness of a portion of the three-degree-of-freedom bearing radial core structure on the outer periphery of the second cavity. This further shortens the radial dimension of the thrust disk, further reduces the air friction loss of the rotor, and achieves the same unilateral axial output force with a smaller thrust disk outer diameter. At the same time, axial force control can be achieved with a smaller axial control current, reducing losses.

[0083] In some implementations...

[0084] It also includes a three-degree-of-freedom bearing radial housing 5, a portion of which is located on the outer periphery of the three-degree-of-freedom bearing radial core 8, a portion of which is located on the outer periphery of the magnetic ring 7, and a portion of which is located on the outer periphery of a portion of the three-degree-of-freedom bearing axial core 3, such that the three-degree-of-freedom bearing radial core 8, the magnetic ring 7, and the three-degree-of-freedom bearing axial core 3 are respectively fixed to the three-degree-of-freedom bearing radial housing 5.

[0085] This is a preferred structural form of the three-degree-of-freedom bearing of this utility model. The magnetic ring, the radial iron core, and the axial iron core of the three-degree-of-freedom bearing can be connected into one unit through the radial housing of the three-degree-of-freedom bearing.

[0086] This utility model also provides a compressor (preferably a magnetic levitation compressor), which includes the aforementioned three-degree-of-freedom magnetic levitation bearing structure 100, and also includes a rotor 1, which is located on the inner periphery of the thrust disk 2, the three-degree-of-freedom bearing axial iron core 3 and the magnetic ring 7.

[0087] The compressor of this invention includes an axially asymmetric three-degree-of-freedom bearing, which can increase the magnetic pole area of ​​the thrust disc on one side and the axial bearing, thereby making the axial output performance of one side stronger. Under specific working conditions, it can achieve the output level of existing solutions with a smaller axial current, thus reducing losses.

[0088] This invention can reduce axial current and provide the same axial output force (support force) as the prior art with a smaller axial current, thereby reducing heat generation. Reducing the diameter of the thrust disk can also reduce heat generation, enhance dynamic characteristics, and make the modes better (less prone to resonance).

[0089] The axial asymmetric three-degree-of-freedom bearing provided by this utility model, through its stepped structure at the rotor mounting thrust plate position (the original technology has a symmetrical arrangement on both sides of the thrust plate, while this utility model has an asymmetric structure relative to the thrust plate, that is, the contact area between the bearing axial iron core and the thrust plate is greater than the contact area between the magnetic ring and the thrust plate), can meet the output requirements (the effect on the bearing) with a smaller outer diameter of the thrust plate, and can effectively reduce the air friction loss at the rotor thrust plate.

[0090] The axial asymmetric three-degree-of-freedom bearing of this invention, by cooperating with the stepped structure of the rotor mounting thrust disk position, can effectively reduce the outer diameter of the rotor thrust disk, and increase the first-order bending frequency of the rotor while keeping other design parameters unchanged, thereby obtaining better dynamic characteristics (less prone to resonance, and better rotor performance).

[0091] In some implementations...

[0092] It also includes a motor stator 10, and the rotor 1 includes at least one stepped surface 14 located on one side of the axial direction of the motor stator 10 and at least one stepped surface 14 located on the other side of the axial direction of the motor stator 10. The stepped surfaces 14 on both sides of the axial direction of the motor stator 10 are symmetrically arranged with respect to the motor stator 10. The three-degree-of-freedom magnetic levitation bearing structure is provided at the stepped surface 14 on one side of the axial direction of the motor stator 10, and the three-degree-of-freedom magnetic levitation bearing structure 100 is also provided at the stepped surface 14 on the other side of the axial direction of the motor stator 10.

[0093] Based on the overall layout of the compressor, the three-degree-of-freedom bearing of this utility model will mainly have two categories of overall technical solutions. Figure 2 The diagram shows the overall design of the existing technology. The compressor has a centrally located motor layout. One side of the rotor has a three-degree-of-freedom bearing and a thrust plate, while the other side has a two-degree-of-freedom radial bearing. The three-degree-of-freedom bearing has an axially symmetrical structure, thus achieving five-degree-of-freedom suspension control of the compressor rotor. Figure 5 The overall structure of this utility model's technical solution 1 is the same as that of existing solutions, with a three-degree-of-freedom bearing and thrust disc arranged on one side and a two-degree-of-freedom radial bearing arranged on the other side. It is mainly used in machine models subjected to continuous axial force on one side. The side with higher axial output performance... Figure 5 The axial core 3 of the three-degree-of-freedom bearing is assembled with the continuous axial output direction, which can achieve axial suspension control with a smaller axial current. At the same time, the reduction of the outer diameter of the thrust disk can increase the first-order bending frequency of the rotor, and have a larger resonance isolation margin under the same speed conditions, so that the rotor vibrates less when running at high speed. Figure 7 Overall technical solution of this utility model Figure 2 This approach involves symmetrically distributing three-degree-of-freedom bearings on both sides of the compressor rotor, further reducing the outer diameter of the inference force plate. The axial portion of the three-degree-of-freedom bearing on one side only provides axial force on that side, and axial control is achieved through the combined axial portions of the three-degree-of-freedom bearings on both sides. This layout can be applied to a wider range of operating conditions.

[0094] The bearings of this invention can also be symmetrically arranged on both sides of the rotor, which can enhance the axial force output performance of the rotor, while reducing the axial control current to reduce losses and heat generation. This effectively solves the problem that the existing three-degree-of-freedom magnetic levitation bearings have a large axial current due to the symmetrical force output design of the axial bearing part, which causes large losses.

[0095] This utility model designs the axial bearing of a three-degree-of-freedom bearing to be asymmetrical through structural design, as shown in the proposed solution. Figure 4 As shown, this asymmetric design, due to its special magnetic circuit, can achieve a larger unilateral axial output force with a smaller current. It can be applied to specific working conditions where the axial force is more biased to one side, reducing the axial current. Simultaneously, the thrust disk adopts a more optimized design, reducing its diameter, improving the rotor's dynamic characteristics at high speeds, and reducing losses and heat generation. This utility model solution is simple. Figure 6 The diagram shows a scheme in which the axially asymmetric three-degree-of-freedom bearing is arranged at both ends of the rotor. In this case, the axial rotor can be suspended by a smaller axial current, and a smaller diameter thrust disk design can be used, so that the rotor has better dynamic characteristics while reducing losses.

[0096] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. The above description is only a preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A three degree of freedom magnetic levitation bearing structure, characterized by: include: The rotor (1) comprises a thrust disk (2), a three-degree-of-freedom bearing axial core (3), and a magnetic ring (7). The thrust disk (2) is disposed on the stepped surface (14) of the rotor (1). At least a portion of the structure of the three-degree-of-freedom bearing axial core (3) is located at one axial end of the thrust disk (2) and can abut against the thrust disk (2). At least a portion of the structure of the magnetic ring (7) is located at the other axial end of the thrust disk (2) and can abut against the thrust disk (2). Along the axial direction of the rotor (1), the area of ​​the three-degree-of-freedom bearing axial core (3) relative to the thrust disk (2) along the axial direction is larger than the area of ​​the magnetic ring (7) relative to the thrust disk (2) along the axial direction.

2. The three-degree-of-freedom magnetic levitation bearing structure according to claim 1, characterized in that: In the longitudinal section plane passing through the axis of the rotor (1), along the radial direction of the rotor (1), the radial length of the three-degree-of-freedom bearing axial core (3) and the thrust disk (2) relative to each other along the axial direction is longer than the radial length of the magnetic ring (7) and the thrust disk (2) relative to each other along the axial direction; so that the contact area of ​​the three-degree-of-freedom bearing axial core (3) and the thrust disk (2) along the axial direction is larger than the contact area of ​​the magnetic ring (7) and the thrust disk (2) along the axial direction.

3. The three-degree-of-freedom magnetic levitation bearing structure according to claim 1, characterized in that: The thrust disk (2) along the radial direction of the rotor (1) includes a first segment and a second segment connected together. The first segment is opposite to the step surface (14) of the rotor (1) along the axial direction. The second segment is not opposite to the step surface (14) along the axial direction. The second segment is located on the radial outer periphery of the first segment along the radial direction of the rotor (1). The radial inner end of the axial core (3) of the three-degree-of-freedom bearing is opposite to the first segment along the axial direction of the rotor (1), and the radial inner end of the magnetic ring (7) is opposite to the second segment along the axial direction of the rotor (1).

4. The three-degree-of-freedom magnetic levitation bearing structure according to claim 1, characterized in that: The rotor (1) includes a first shaft segment (15) and a second shaft segment (16), the outer diameter of the first shaft segment (15) is smaller than the outer diameter of the second shaft segment (16), the first shaft segment (15) and the second shaft segment (16) are axially connected to form the stepped surface (14) at the connection, the stepped surface (14) is at least a portion of the axial end face of the second shaft segment (16); The radial inner end of the axial core (3) of the three-degree-of-freedom bearing is opposite to the first shaft segment (15) along the radial direction of the rotor (1). The radial inner end of the axial core (3) of the three-degree-of-freedom bearing has a first gap with the first shaft segment (15) along the radial direction. The radial length of the first gap is smaller than the radial length of the stepped surface (14) along the radial direction of the rotor (1).

5. The three-degree-of-freedom magnetic levitation bearing structure according to claim 4, characterized in that: The inner radial end of the magnetic ring (7) is opposite to the second shaft segment (16) along the radial direction of the rotor (1), and the inner radial end of the magnetic ring (7) and the second shaft segment (16) have a second gap along the radial direction; along the radial direction of the rotor (1), the radial dimension of the first gap is smaller than the radial dimension of the second gap.

6. The three-degree-of-freedom magnetic levitation bearing structure according to claim 1, characterized in that: It also includes an axial winding (4) and a radial winding (9). The axial winding (4) is located on the radial outer periphery of the thrust disk (2) and is spaced at a predetermined distance from the thrust disk (2). The radial winding (9) is located on the axial side of the magnetic ring (7) away from the thrust disk (2), such that the magnetic ring (7) is located between the thrust disk (2) and the radial winding (9) and along the axial direction of the rotor (1). At least a portion of the structure of the axial winding (4) is axially opposite to at least a portion of the structure of the radial winding (9). The radial outer end of the thrust disk (2) is opposite to the radial inner end of the radial winding (9) in the axial direction, or the radial outer end of the thrust disk (2) is not opposite to the radial inner end of the radial winding (9) in the axial direction and is located at a position opposite to the radial inner side of the radial winding (9).

7. The three-degree-of-freedom magnetic levitation bearing structure according to claim 6, characterized in that: At least a portion of the structure of the three-degree-of-freedom bearing axial core (3) is located on the radial outer periphery of the axial winding (4). The radial inner periphery of at least a portion of the structure of the three-degree-of-freedom bearing axial core (3) forms a first cavity (17). The axial winding (4) and the thrust disk (2) are disposed in the first cavity (17). The three-degree-of-freedom bearing radial core (8) also includes a three-degree-of-freedom bearing radial core (8). The three-degree-of-freedom bearing radial core (8) has a second cavity (18) located on the radial inner periphery of a portion of its structure. At least a portion of the structure of the radial winding (9) is located in the second cavity (18). The radial inner periphery wall of the first cavity (17) and the radial inner periphery wall of the second cavity (18) are opposite to each other along the axial direction of the rotor (1), or the radial inner side of the radial inner periphery wall of the first cavity (17) and the radial inner periphery wall of the second cavity (18) are opposite to each other along the axial direction of the rotor (1).

8. The three-degree-of-freedom magnetic levitation bearing structure according to claim 7, characterized in that: The axial core (3) of the three-degree-of-freedom bearing is located at one axial end of the magnetic ring (7) and is connected to the end face of one axial end of the magnetic ring (7). The radial core (8) of the three-degree-of-freedom bearing is located at the other axial end of the magnetic ring (7) and is connected to the end face of the other axial end of the magnetic ring (7). The radial thickness of a portion of the structure of the axial core (3) of the three-degree-of-freedom bearing on the outer periphery of the first cavity (17) is not less than the radial thickness of a portion of the structure of the radial core (8) of the three-degree-of-freedom bearing on the outer periphery of the second cavity (18).

9. The three-degree-of-freedom magnetic levitation bearing structure according to claim 7, characterized in that: It also includes a three-degree-of-freedom bearing radial housing (5), a portion of which is located on the outer periphery of the three-degree-of-freedom bearing radial core (8), a portion of which is located on the outer periphery of the magnetic ring (7), and a portion of which is located on the outer periphery of a portion of the three-degree-of-freedom bearing axial core (3), such that the three-degree-of-freedom bearing radial core (8), the magnetic ring (7), and the three-degree-of-freedom bearing axial core (3) are respectively fixed to the three-degree-of-freedom bearing radial housing (5).

10. A compressor, characterized in that: The three-degree-of-freedom magnetic levitation bearing structure according to any one of claims 1-9 further includes a rotor (1), the rotor (1) being located on the inner periphery of the thrust disk (2), the three-degree-of-freedom bearing axial core (3) and the magnetic ring (7).

11. The compressor according to claim 10, characterized in that: It also includes a motor stator (10), the rotor (1) includes at least one stepped surface (14) on one side of the axial direction of the motor stator (10) and at least one stepped surface (14) on the other side of the axial direction of the motor stator (10), the stepped surfaces (14) on both sides of the axial direction of the motor stator (10) are symmetrically arranged with respect to the motor stator (10); and the three-degree-of-freedom magnetic levitation bearing structure is provided at the stepped surface (14) on one side of the axial direction of the motor stator (10), and the three-degree-of-freedom magnetic levitation bearing structure is also provided at the stepped surface (14) on the other side of the axial direction of the motor stator (10).

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