Magnetic bearing protection devices, motors, compressors and air conditioners

Abstract

The present application provides a magnetic bearing protection device, a motor, a compressor and an air conditioner. The magnetic bearing protection device includes a rotor, a thrust plate, a front axial core, a rear axial core, a bearing seat, a protective bearing, a positioning ring and an axial limiter. The positioning ring has an external thread and an inner retaining ring. The positioning ring is threaded with the bearing seat. The protective bearing is sleeved in the positioning ring. The inner retaining ring is located on the axial inner side of the protective bearing. The axial limiter is located on the axial outer side of the protective bearing. A stop step and a rear retaining shoulder are provided on the rotor. The stop step and the rear retaining shoulder form a limit groove. The inner ring of the protective bearing is located in the limit groove. According to the magnetic bearing protection device of the present application, when the rotor is axially unstable, it can effectively avoid the collision between the thrust plate and the magnetic bearing, thereby improving the operating reliability of the magnetic bearing.

Description

Technical Field

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

[0002] Related technologies disclose a method for adjusting the assembly gap between a magnetic bearing, an auxiliary bearing and a rotor, which applies a load to a compressible and deformable spring laminate through a clamping block to adjust the axial position of the protective bearing in the bearing seat, thereby changing the projection position on the rotor. However, the spring laminate has a small stiffness and poor impact resistance. When the rotor becomes axially unstable and collides, there is a risk of failure of the spring laminate or large deformation, resulting in a collision between the thrust plate and the magnetic bearing. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present application is to provide a magnetic bearing protection device, a motor, a compressor and an air conditioner, which can effectively prevent the thrust plate from colliding with the magnetic bearing when the rotor is axially unstable, thereby improving the operating reliability of the magnetic bearing.

[0004] In order to solve the above problems, the present application provides a magnetic bearing protection device, including a rotor, a thrust plate, a front axial iron core, a rear axial iron core, a bearing seat, a protective bearing, a positioning ring and an axial limit piece, the thrust plate is installed on the rotor, the front axial iron core and the rear axial iron core are located at both ends of the thrust plate, the bearing seat is fixed relative to the rear axial iron core, the inner circumferential wall of the bearing seat is provided with an internal thread, the positioning ring has an external thread and an inner retaining ring, the positioning ring is sleeved in the bearing seat and cooperates with the bearing seat thread, the protective bearing is sleeved in the positioning ring, and the inner retaining ring It is located on the axial inner side of the protective bearing, the axial limit piece is located on the axial outer side of the protective bearing, the inner stop ring cooperates with the axial limit piece to form an axial limit for the outer ring of the protective bearing, a stop step and a rear shoulder are provided on the rotor, the stop step and the rear shoulder form a limit groove, the inner ring of the protective bearing is located in the limit groove, the gap between the inner ring and the stop step is d1, the gap between the inner ring and the rear shoulder is d2, the gap between the thrust plate and the front axial iron core is b1, the gap between the thrust plate and the rear axial iron core is b2, wherein b1>d2, b2>d1.

[0005] Preferably, a radial stator core is further sleeved outside the rotor, a radial gap between the radial stator core and the rotor is a, a radial gap between the protective bearing and the rotor is c, and a>c.

[0006] Preferably, one end of the protective bearing facing the axial limiter extends out of the positioning ring in the axial direction, and the extension length is l1, where l1>0.

[0007] Preferably, the inner circumferential wall of the bearing seat further includes a radial positioning section, which is located axially inside the internal thread, and the positioning ring further includes a smooth shaft section, which is sleeved with the radial positioning section.

[0008] Preferably, the inner circumferential wall of the bearing seat includes a groove section, a step is formed between the groove section and the radial positioning section, the internal thread is located on the side wall of the groove section, the positioning ring includes a convex ring section, the external thread is located on the convex ring section, and the convex ring section is located in the groove section.

[0009] Preferably, the axial limiter is arranged on the end surface of the bearing seat and is bolted to the bearing seat, and the bolts can adjust the distance between the axial limiter and the protective bearing.

[0010] Preferably, the axial limiter has an external thread, and the external thread of the axial limiter matches with the internal thread of the bearing seat to adjust the distance between the axial limiter and the protective bearing.

[0011] Preferably, the axial limiting member is provided with a flange protruding toward the outer ring of the protective bearing.

[0012] Preferably, the axial limiter and the positioning ring are provided with pin holes, the axial limiter is provided with an arc-shaped connecting hole for connecting with the bearing seat, and the arc-shaped connecting hole is coaxially arranged with the positioning ring.

[0013] Preferably, a rotation groove is provided on the end surface of the positioning ring facing the axial outside.

[0014] Preferably, a portion of the rotor located axially outside the protective bearing is provided with a positioning step, and the rear shoulder is axially limited on the positioning step.

[0015] Preferably, the rotor is provided with an external thread, the rear shoulder has an internal thread, and the rear shoulder and the rotor are thread-matched.

[0016] Preferably, the rotor is provided with an external thread, and a locking nut is provided on the axial outer side of the rear shoulder. The locking nut cooperates with the rotor thread and is locked on the axial outer side of the rear shoulder.

[0017] Preferably, the locating ring and the bearing seat are matched with fine pitch threads.

[0018] Preferably, the protective bearing is a deep groove ball bearing or an angular contact ball bearing.

[0019] Preferably, the protective bearing is a ceramic ball bearing.

[0020] According to another aspect of the present application, a motor is provided, comprising a magnetic bearing protection device, wherein the magnetic bearing protection device is the above-mentioned magnetic bearing protection device.

[0021] According to another aspect of the present application, a compressor is provided, comprising a magnetic bearing protection device, wherein the magnetic bearing protection device is the above-mentioned magnetic bearing protection device.

[0022] According to another aspect of the present application, an air conditioner is provided, comprising a magnetic bearing protection device, wherein the magnetic bearing protection device is the above-mentioned magnetic bearing protection device.

[0023] The magnetic bearing protection device provided by the present application includes a rotor, a thrust plate, a front axial iron core, a rear axial iron core, a bearing seat, a protective bearing, a positioning ring and an axial limit piece. The thrust plate is installed on the rotor, the front axial iron core and the rear axial iron core are located at both ends of the thrust plate, the bearing seat is fixed relative to the rear axial iron core, the inner circumferential wall of the bearing seat is provided with an internal thread, the positioning ring has an external thread and an inner retaining ring, the positioning ring is sleeved in the bearing seat and cooperates with the bearing seat thread, the protective bearing is sleeved in the positioning ring, and the inner retaining ring is located at the protective shaft The axial inner side of the bearing, the axial limiter is located at the axial outer side of the protective bearing, the inner stop ring cooperates with the axial limiter to form an axial limit for the outer ring of the protective bearing, a stop step and a rear stop shoulder are provided on the rotor, the stop step and the rear stop shoulder form a limit groove, the inner ring of the protective bearing is located in the limit groove, the gap between the inner ring and the stop step is d1, the gap between the inner ring and the rear stop shoulder is d2, the gap between the thrust plate and the front axial iron core is b1, and the gap between the thrust plate and the rear axial iron core is b2, wherein b1>d2, b2>d1. The magnetic suspension bearing protection device installs the protective bearing in the positioning ring, and adjusts the axial installation position of the protective bearing through the spiral pair formed between the positioning ring and the bearing seat, which can conveniently realize the adjustment of the axial position of the protective bearing, making the magnetic suspension bearing protection device more versatile and simplifying the assembly process. At the same time, the axial adjustment formed by the spiral pair can be used to ensure the impact resistance of the protective bearing, which can effectively avoid the collision between the thrust plate and the magnetic suspension bearing when the rotor is axially unstable, and improve the operation reliability of the magnetic suspension bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of a magnetic bearing protection device according to an embodiment of the present application;

[0025] Figure 2 for Figure 1 A schematic diagram of the enlarged structure at I;

[0026] Figure 3 This is a schematic structural diagram of an axial stopper of a magnetic bearing protection device according to an embodiment of the present application;

[0027] Figure 4 This is a schematic structural diagram of a positioning ring of a magnetic bearing protection device according to an embodiment of the present application.

[0028] The reference numerals are:

[0029] 1. Rotor; 2. Radial stator core; 3. Front axial core; 4. Rear axial core; 5. Bearing seat; 6. Positioning ring; 61. Rotation slot; 62. Inner retaining ring; 7. Axial limiter; 71. Arc-shaped connecting hole; 72. Pin hole; 73. Flange; 8. Pin; 9. Rear shoulder; 10. Locking nut; 11. Thrust plate; 12. Protective bearing; 13. Stop step; 14. Positioning step. DETAILED DESCRIPTION

[0030] See also Figures 1 to 4 As shown, according to an embodiment of the present application, the magnetic bearing protection device includes a rotor 1, a thrust plate 11, a front axial core 3, a rear axial core 4, a bearing seat 5, a protective bearing 12, a positioning ring 6 and an axial limiter 7. The thrust plate 11 is installed on the rotor 1, the front axial core 3 and the rear axial core 4 are located at both ends of the thrust plate 11, the bearing seat 5 is fixed relative to the rear axial core 4, the inner circumferential wall of the bearing seat 5 is provided with an internal thread, the positioning ring 6 has an external thread and an inner retaining ring 62, the positioning ring 6 is sleeved in the bearing seat 5 and is threadedly matched with the bearing seat 5, the protective bearing 12 is sleeved in the positioning ring 6, and the inner retaining ring 62 is located at the protection shaft The axial inner side of the protective bearing 12, the axial limit piece 7 is located on the axial outer side of the protective bearing 12, the inner stop ring 62 cooperates with the axial limit piece 7 to form an axial limit for the outer ring of the protective bearing 12, and a stop step 13 and a rear shoulder 9 are provided on the rotor 1. The stop step 13 and the rear shoulder 9 form a limit groove, and the inner ring of the protective bearing 12 is located in the limit groove. The axial clearance between the inner ring and the stop step 13 is d1, and the axial clearance between the inner ring and the rear shoulder 9 is d2. The axial clearance between the thrust plate 11 and the front axial core 3 is b1, and the axial clearance between the thrust plate 11 and the rear axial core 4 is b2, wherein b1>d2, b2>d1.

[0031] The magnetic bearing protection device installs the protection bearing 12 in the positioning ring 6, and adjusts the axial installation position of the protection bearing 12 by means of the spiral pair formed between the positioning ring 6 and the bearing seat 5, which can conveniently realize the adjustment of the axial position of the protection bearing, making the magnetic bearing protection device more versatile and simplifying the assembly process. At the same time, the axial adjustment formed by the spiral pair can be used to ensure the impact resistance of the protection bearing 12, and can effectively avoid the collision between the thrust plate 11 and the magnetic bearing when the rotor is axially unstable, thereby improving the operating reliability of the magnetic bearing.

[0032] In this embodiment, since there is a threaded fit relationship between the locating ring 6 and the bearing seat 5, the axial position of the locating ring 6 can be adjusted by threaded fit. Therefore, the different axial clearances between the protective bearing and the rotor stop step 13 and the rear shoulder 9 can be adjusted according to different magnetic bearings and rotors, so that the threaded fit structure of the locating ring 6 and the bearing seat 5 can be suitable for different types of protective bearing settings, with better adaptability and simpler assembly requirements.

[0033] In this embodiment, when the rotor 1 becomes unstable, if the rotor 1 moves forward, since the axial clearance between the thrust plate 11 and the front axial core 3 is b1, and the axial clearance between the inner ring and the rear shoulder 9 is d2, b1>d2, the rotor 1 will drive the rear shoulder 9 to move forward, and the rear shoulder 9 will first contact the protective bearing 12, so it can prevent the thrust plate 11 from hitting the front axial core 3, thereby forming effective axial protection for the front axial core 3.

[0034] Similarly, if the rotor 1 moves backward, since the axial clearance between the thrust plate 11 and the rear axial core 4 is b2, and the axial clearance between the inner ring and the stop step 13 is d1, b2>d1, the rotor 1 will drive the stop step 13 to move backward, and the stop step 13 will first contact the protective bearing 12, thereby preventing the thrust plate 11 from hitting the rear axial core 4, thereby forming effective axial protection for the rear axial core 4.

[0035] In one embodiment, b1+b2>d1+d2, b1=b2, d1=d2, which can ensure the centering of the protective bearing 12 and improve the protective performance of the protective bearing 12 on the magnetic suspension bearing.

[0036] In one embodiment, a radial stator core 2 is further sleeved outside the rotor 1, a radial gap between the radial stator core 2 and the rotor 1 is a, a radial gap between the protective bearing 12 and the rotor 1 is c, and a>c.

[0037] In this embodiment, since a>c, when the rotor 1 loses stability and moves radially, the rotor 1 will first contact the inner ring of the protective bearing 12 and be stopped by the inner ring of the protective bearing 12, so it will not come into contact with the radial stator core 2, which can effectively protect the radial stator core 2 and prevent the rotor 1 from colliding with the radial stator core 2 and damaging the radial stator core 2.

[0038] The protective bearing 12 of this embodiment can provide both axial protection and radial protection for the magnetic bearing, thus integrating the radial protection and axial protection of the magnetic bearing into one, simplifying the structure of the magnetic protection system, reducing accessories, and effectively reducing costs.

[0039] In one embodiment, one end of the protective bearing 12 toward the axial limit member 7 axially extends out of the positioning ring 6, and the extension length is l1, l1>0, thereby ensuring that the protective bearing 12 axially protrudes out of the positioning ring 6 toward the axial limit member 7, and can easily achieve the axial limit cooperation between the axial limit member 7 and the protective bearing 12, avoiding the axial limit between the axial limit member 7 and the protective bearing 12 being affected by the structure of the positioning ring 6.

[0040] In one embodiment, the inner circumferential wall of the bearing seat 5 further includes a radial positioning section, which is located axially inside the internal thread, and the positioning collar 6 further includes a smooth shaft section, which is sleeved with the radial positioning section. In this embodiment, by providing a radial positioning section on the inner circumferential wall of the bearing seat 5 and providing a smooth shaft section at a corresponding position of the positioning collar 6, the radial positioning section and the smooth shaft section can be used to cooperate to achieve the radial positioning and load-bearing function of the protective bearing 12, ensure the radial position of the protective bearing 12 is accurate, and can effectively protect the magnetic suspension bearing through the protective bearing 12.

[0041] In one embodiment, the inner peripheral wall of the bearing seat 5 includes a recessed groove section, a step is formed between the recessed groove section and the radial positioning section, the internal thread is located on the side wall of the recessed groove section, and the positioning ring 6 includes a convex ring section, the external thread is located on the convex ring section, and the convex ring section is located in the recessed groove section. In this embodiment, by setting the recessed groove section, the bearing seat 5 can be designed in sections, so that the radial positioning section and the threaded connection section including the internal thread are at different radial heights, and the processing accuracy of the radial positioning section can be guaranteed without affecting the setting of the internal thread, so that the radial positioning section and the positioning ring 6 can be matched to facilitate radial positioning of the protective bearing 12. Similarly, by setting the convex ring section and the halo shaft section, it is not only convenient to realize the connection and positioning with the bearing seat 5, but also the step formed between the recessed groove section and the radial positioning section can be used to limit the axial displacement of the positioning ring 6, thereby improving the stability and reliability of the matching structure between the bearing seat 5 and the positioning ring 6.

[0042] In one embodiment, the axial limiter 7 is arranged on the end face of the bearing seat 5 and is connected to the bearing seat 5 by bolts, and the bolts can adjust the distance between the axial limiter 7 and the protective bearing 12. In this embodiment, as the axial position of the positioning ring 6 is adjusted, the circumferential position of the protective bearing 12 will also be adjusted accordingly. In order to ensure the axial limit of the protective bearing 12, the axial position of the axial limiter 7 also needs to be able to be adjusted accordingly. In this embodiment, the axial limiter 7 is connected to the bearing seat 5 by bolts. When the axial limiter 7 abuts against the protective bearing 12, the axial limiter 7 is fixed to the protective bearing 12 by bolts. At the same time, since the bolts are fixedly connected to the bearing seat 5, the fixed connection between the axial limiter 7 and the bearing seat 5 can also be achieved. In this embodiment, the axial limiter 7 is, for example, a bearing end cover.

[0043] In one embodiment, the axial stopper 7 has an external thread, and the external thread of the axial stopper 7 cooperates with the internal thread of the bearing seat 5 to adjust the distance between the axial stopper 7 and the protective bearing 12. During the axial position adjustment of the positioning ring 6, the axial stopper 7 is also adjusted with the displacement of the positioning ring 6. Since the axial stopper 7 and the bearing seat 5 are in a threaded matching relationship, the axial position of the axial stopper 7 in the bearing seat 5 can be easily adjusted, thereby ensuring that the axial position of the protective bearing 12 can always be achieved by cooperating with the positioning ring 6.

[0044] In one embodiment, the axial limit member 7 is provided with a flange 73 protruding toward the outer ring of the protective bearing 12, so that the portion of the axial limit member 7 corresponding to the outer ring of the protective bearing 12 can protrude axially toward the outer ring of the protective bearing 12, and press the outer ring of the protective bearing 12 tightly, thereby making it easier to achieve axial positioning and pre-tightening of the protective bearing 12 and the positioning ring 6.

[0045] In one embodiment, the axial limiter 7 and the positioning collar 6 are provided with a pin hole 72, and a pin 8 for circumferentially limiting the positioning collar 6 is provided in the pin hole 72. The axial limiter 7 is provided with an arc-shaped connection hole 71 for connecting with the bearing seat 5, and the arc-shaped connection hole 71 is coaxially arranged with the positioning collar 6. In this embodiment, the arc-shaped connection hole 71 can adjust the circumferential position of the axial limiter 7 relative to the positioning collar 6, so that the pin hole 72 on the axial limiter 7 can be aligned with the pin hole 72 on the positioning collar 6, effectively avoiding the situation that the positioning collar 6 and the pin hole 72 of the axial limiter 7 cannot be aligned, and improving the adaptability of the pin connection between the positioning collar 6 and the axial limiter 7.

[0046] By means of the cooperation of the pins between the positioning ring 6 and the axial stopper 7, the positioning ring 6 can be positioned circumferentially, thereby preventing the positioning ring 6 from axial displacement, thereby improving the structural stability and reliability of the magnetic bearing protection device.

[0047] In one embodiment, a rotation slot 61 is provided on the end surface of the positioning collar 6 facing the axial outer side. In this embodiment, the rotation slot 61 can be operated by torque, so it is convenient to apply torque to the positioning collar 6 during the process of adjusting the axial position, reducing the difficulty of adjustment. The number of the rotation slots 61 is, for example, two, and they are arranged symmetrically along the end surface center of the positioning collar 6.

[0048] In one embodiment, a portion of the rotor 1 located axially outside the protective bearing 12 is provided with a positioning step 14, and the rear shoulder 9 is axially limited on the positioning step 14. In this embodiment, the axial position of the rear shoulder 9 can be accurately positioned through the cooperation between the positioning step 14 and the rear shoulder 9, thereby ensuring the axial limiting accuracy of the rear shoulder 9 to the protective bearing.

[0049] In one embodiment, the rotor 1 is provided with external threads, the rear shoulder 9 has internal threads, and the rear shoulder 9 is threadedly matched with the rotor 1. In this embodiment, the rear shoulder 9 not only realizes the axial limit of the protective bearing 12, but also realizes its own axial positioning by using the thread structure.

[0050] In this embodiment, the axial limitation of the rotor 1 for the protective bearing 12 and the rear shoulder 9 is achieved by providing a step shaft to form a step.

[0051] In one embodiment, the rotor 1 is provided with an external thread, and a locking nut 10 is provided on the axial outer side of the rear shoulder 9. The locking nut 10 is threadedly matched with the rotor 1, and the locking nut 10 is locked on the axial outer side of the rear shoulder 9. In this embodiment, the axial limit accuracy of the rear shoulder 9 for protecting the bearing 12 is achieved by the processing accuracy of the rear shoulder 9 itself and the matching accuracy of the rotor 1. The processing accuracy of the locking nut 10 does not need to be considered, and it only needs to be able to lock the axial position of the rear shoulder 9. Therefore, the processing accuracy requirement is reduced, the processing cost is lower, and the axial limit accuracy of the protective bearing 12 is also easier to ensure.

[0052] In one embodiment, the positioning ring 6 and the bearing seat 5 are matched with fine pitch threads. In this embodiment, the thread type of the screw pair is preferably a fine pitch metric triangular thread, which has good self-locking properties and can effectively improve the self-locking performance between the positioning ring 6 and the bearing seat 5.

[0053] In one embodiment, the protective bearing 12 is a deep groove ball bearing or an angular contact ball bearing, and may be a steel ball bearing or a ceramic ball bearing.

[0054] As a preferred embodiment, the protective bearing 12 is an angular contact ceramic ball bearing.

[0055] During the assembly process of the magnetic suspension bearing protection device, the axial limiter 7 and the pin 8 are not assembled first. The positioning ring 6 is rotated to the front end, and the rotor 1 is sucked to the front end. At this time, the thrust plate 11 is in contact with the front axial core 3. The positioning ring 6 is rotated backward so that the protection bearing 12 is in contact with the rear shoulder 9, and the amount of backward movement of the rotor 1 is ensured to be (b1+b2-d1-d2) / 2, that is, the axial clearance is adjusted to the right position. When the rotor 1 is suspended, the thrust plate 11 is located between the front axial core 3 and the rear axial core 4 under the action of the axial magnetic suspension force, and the protection bearing 12 is located between the stop step 13 and the rear shoulder 9. Then the pin 8 is nailed in and the locking axial limiter 7 is assembled.

[0056] According to an embodiment of the present application, the motor includes a magnetic bearing protection device, which is the magnetic bearing protection device mentioned above.

[0057] According to an embodiment of the present application, the compressor includes a magnetic bearing protection device, which is the above-mentioned magnetic bearing protection device.

[0058] According to an embodiment of the present application, the air conditioner includes a magnetic bearing protection device, which is the above-mentioned magnetic bearing protection device.

[0059] 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.

[0060] 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 protection device, characterized in that: The invention comprises a rotor (1), a thrust plate (11), a front axial core (3), a rear axial core (4), a bearing seat (5), a protective bearing (12), a positioning ring (6) and an axial stopper (7), wherein the thrust plate (11) is mounted on the rotor (1), the front axial core (3) and the rear axial core (4) are located at two ends of the thrust plate (11), the bearing seat (5) is fixedly arranged relative to the rear axial core (4), the inner peripheral wall of the bearing seat (5) is provided with an internal thread, the positioning ring (6) has an external thread and an inner retaining ring (62), the positioning ring (6) is sleeved in the bearing seat (5) and is threadedly matched with the bearing seat (5), the protective bearing (12) is sleeved in the positioning ring (6), and the inner retaining ring (62) is located at the protective bearing ( The protective bearing (12) is axially inner than the axial inner side of the protective bearing (12), the axial limiting member (7) is located on the axial outer side of the protective bearing (12), the inner stop ring (62) cooperates with the axial limiting member (7) to form an axial limit for the outer ring of the protective bearing (12), a stop step (13) and a rear stop shoulder (9) are provided on the rotor (1), the stop step (13) and the rear stop shoulder (9) form a limit groove, the inner ring of the protective bearing (12) is located in the limit groove, the gap between the inner ring and the stop step (13) is d1, the gap between the inner ring and the rear stop shoulder (9) is d2, the gap between the thrust plate (11) and the front axial core (3) is b1, and the gap between the thrust plate (11) and the rear axial core (4) is b2, wherein b1>d2, b2>d1.

2. The magnetic bearing protection device according to claim 1, characterized in that: A radial stator core (2) is also sleeved outside the rotor (1), a radial gap between the radial stator core (2) and the rotor (1) is a, and a radial gap between the protective bearing (12) and the rotor (1) is c, where a>c.

3. The magnetic bearing protection device according to claim 1, characterized in that: One end of the protective bearing (12) facing the axial limiting member (7) extends axially out of the positioning ring (6), and the extension length is l1, where l1>0.

4. The magnetic bearing protection device according to claim 1, characterized in that: The inner peripheral wall of the bearing seat (5) further comprises a radial positioning section, which is located axially inside the internal thread. The positioning ring (6) further comprises a smooth shaft section, which is sleeved with the radial positioning section.

5. The magnetic bearing protection device according to claim 4, characterized in that: The inner peripheral wall of the bearing seat (5) includes a recessed groove section, a step is formed between the recessed groove section and the radial positioning section, the internal thread is located on the side wall of the recessed groove section, the positioning ring (6) includes a convex ring section, the external thread is located on the convex ring section, and the convex ring section is located in the recessed groove section.

6. The magnetic bearing protection device according to claim 1, characterized in that: The axial limiter (7) is arranged on the end surface of the bearing seat (5) and is bolted to the bearing seat (5), and the bolt can adjust the distance between the axial limiter (7) and the protective bearing (12).

7. The magnetic bearing protection device according to claim 1, characterized in that: The axial limiter (7) has an external thread, and the external thread of the axial limiter (7) cooperates with the internal thread of the bearing seat (5) to adjust the distance between the axial limiter (7) and the protective bearing (12).

8. The magnetic bearing protection device according to claim 6 or 7, characterized in that: The axial limiting member (7) is provided with a flange (73) protruding toward the outer ring of the protective bearing (12).

9. The magnetic bearing protection device according to claim 6, characterized in that: The axial limiting member (7) and the positioning ring (6) are provided with a pin hole (72), and a pin (8) for circumferentially limiting the positioning ring (6) is provided in the pin hole (72). The axial limiting member (7) is provided with an arc-shaped connecting hole (71) for connecting with the bearing seat (5), and the arc-shaped connecting hole (71) is coaxially arranged with the positioning ring (6).

10. The magnetic bearing protection device according to claim 1, characterized in that: The positioning ring (6) is provided with a rotation slot (61) on the end surface facing the axial outside.

11. The magnetic bearing protection device according to claim 1, characterized in that: A portion of the rotor (1) located axially outside the protective bearing (12) is provided with a positioning step (14), and the rear shoulder (9) is axially limited on the positioning step (14).

12. The magnetic bearing protection device according to claim 11, characterized in that: The rotor (1) is provided with an external thread, the rear shoulder (9) has an internal thread, and the rear shoulder (9) and the rotor (1) are thread-matched.

13. The magnetic bearing protection device according to claim 11, characterized in that: The rotor (1) is provided with an external thread, and a locking nut (10) is provided on the axial outer side of the rear shoulder (9). The locking nut (10) is threadably matched with the rotor (1), and the locking nut (10) is locked on the axial outer side of the rear shoulder (9).

14. The magnetic bearing protection device according to claim 1, characterized in that: The positioning ring (6) and the bearing seat (5) are matched with each other through fine pitch threads.

15. The magnetic bearing protection device according to claim 1, characterized in that: The protective bearing (12) is a deep groove ball bearing or an angular contact ball bearing.

16. The magnetic bearing protection device according to claim 15, characterized in that: The protective bearing (12) is a ceramic ball bearing.

17. A motor, comprising a magnetic bearing protection device, characterized in that: The magnetic bearing protection device is the magnetic bearing protection device according to any one of claims 1 to 16.

18. A compressor, comprising a magnetic bearing protection device, characterized in that: The magnetic bearing protection device is the magnetic bearing protection device according to any one of claims 1 to 16.

19. An air conditioner, comprising a magnetic bearing protection device, characterized in that: The magnetic bearing protection device is the magnetic bearing protection device according to any one of claims 1 to 16.

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