A magnetic bearing, compressor

Abstract

The application provides a magnetic suspension bearing and a compressor, wherein the magnetic suspension bearing comprises an outer iron core, a first iron core is sleeved in the outer iron core, a permanent magnet is arranged between the first iron core and the outer iron core, a bearing rotor is sleeved in the first iron core, a first coil is arranged on only one side of the first iron core in the axial direction, the first coil can generate a magnetic field when electrified, the first coil and the permanent magnet can generate an axial magnetic force on the bearing rotor to make the bearing rotor axially suspended, a second coil is wound on the first iron core, the second coil can generate a magnetic field when electrified, and the second coil and the permanent magnet can generate a radial magnetic force on the bearing rotor to make the bearing rotor radially suspended. The magnetic suspension bearing can overcome the defects of the prior art, i.e. two axial coils are needed, the cost is high, and the axial coil occupies a large space.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bearings, in particular to a magnetic bearing and a compressor. BACKGROUND

[0002] The magnetic bearing suspends the rotating shaft by electromagnetic force of the rotor, and the rotating shaft and the stator keep a non-contact state, thus having advantages of no wear, high rotating speed, high precision, long service life, etc. However, compared with the traditional magnetic bearing, the three-degree-of-freedom magnetic bearing integrates the radial bearing and the axial bearing together, generates a bias magnetic field by using a permanent magnet, and simultaneously realizes the movement of the rotating shaft in three degrees of freedom in the radial and axial directions, so as to effectively reduce the volume and mass of the bearing and the length of the rotor, and improve the critical rotating speed of the rotor.

[0003] The existing three-degree-of-freedom magnetic bearing adopts a symmetrical structure with two axial coils distributed on both sides of the bearing, and the axial coils occupy a large space. The two axial coils are inserted into the iron core, and the stability of the axial coil is poor. Moreover, the cost of designing two axial coils is high. SUMMARY

[0004] Therefore, the present application provides a magnetic bearing and a compressor, which can overcome the defects of the prior art, i.e., the need for two axial coils, high cost, and large space occupied by the axial coil.

[0005] In order to solve the above problems, the present application provides a magnetic bearing, which comprises an outer iron core, a first iron core sleeved in the outer iron core, a permanent magnet arranged between the first iron core and the outer iron core, a bearing rotor sleeved in the first iron core, a first coil arranged on only one side of the first iron core in the axial direction, the first coil being capable of generating a magnetic field when electrified, the first coil and the permanent magnet being capable of generating an axial magnetic force on the bearing rotor to suspend the bearing rotor in the axial direction, and a second coil wound on the first iron core, the second coil being capable of generating a magnetic field when electrified, the second coil and the permanent magnet being capable of generating a radial magnetic force on the bearing rotor to suspend the bearing rotor in the radial direction.

[0006] In some embodiments, a skeleton is further included, the skeleton being fixed on the first iron core by a first locking member, and the first coil being wound on the skeleton.

[0007] In some embodiments, one side of the skeleton is fixed on the first iron core by the first locking member.

[0008] In some embodiments, a mounting ring is further included, the mounting ring being sleeved in the outer iron core, a fourth iron core being sleeved in the mounting ring, the first iron core being sleeved in the fourth iron core, a gap being arranged between the fourth iron core and the outer iron core, and the permanent magnet being arranged in the gap.

[0009] In some embodiments, the mounting ring is located on the other axial side of the first core, and the first coil is located between the fourth core and the inner axial side of the outer core.

[0010] In some embodiments, the permanent magnet is a segmented permanent magnet, and the permanent magnets are uniformly distributed between the first core and the outer core along the circumference of the outer core.

[0011] In some embodiments, a fixing frame is arranged between the first core and the outer core, and the fixing frame can limit the displacement of the permanent magnet.

[0012] In some embodiments, the wall surface on the outer radial side of the first core is a first wall surface, the wall surface on the inner radial side of the first core is a second wall surface, the first coil is located on the first core close to the first wall surface, and the second coil is located on the first core close to the second wall surface.

[0013] In some embodiments, the first core is annular, the first core has at least four radial magnetic poles, the second coil is wound on the radial magnetic poles, four second coils are uniformly distributed on the first core, and every two second coils are arranged in a group.

[0014] In some embodiments, the outer core comprises a second core and a third core, the second core and the third core are annular, the longitudinal section of the second core and the third core is C-shaped, the free end on the outer radial side of the second core is formed into a first surface, the free end on the outer radial side of the third core is formed into a second surface, and the first surface and the second surface are opposite and connected.

[0015] In some embodiments, the magnetic suspension bearing can cooperate with a first rotor of an electric machine, and the bearing rotor comprises a first stopper, a fifth core and a second stopper, the first stopper, the fifth core and the second stopper are sleeved on the first rotor, the fifth core is located between the first stopper and the second stopper, and the first stopper and the second stopper cooperate to limit the fifth core.

[0016] In some embodiments, a protection member is further included, the protection member is sleeved on the rotor, and the first stopper, the fifth core and the second stopper are sleeved on the protection member.

[0017] In some embodiments, a magnetic isolation member is arranged between the first stopper and the fifth core and between the second stopper and the fifth core.

[0018] The application further provides a compressor comprising the magnetic bearing.

[0019] The magnetic bearing and the compressor provided by the application have the following advantages: the axial magnetic circuit is provided by arranging the first coil on one side of the first core in the axial direction, the manufacturing process of the coil is reduced, the process is simple, the internal space of the outer core is saved, the installation is convenient, the assembly is stable, and the processing cost of the magnetic bearing is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a sectional view of the magnetic bearing of the embodiment of the application;

[0021] Figure 2 is a front view of the magnetic bearing of the embodiment of the application;

[0022] Figure 3 is a structural schematic view of the fixing frame in the magnetic bearing of the embodiment of the application;

[0023] Figure 4 is a first structural schematic view of the bearing rotor in the magnetic bearing of the embodiment of the application;

[0024] Figure 5 is a second structural schematic view of the bearing rotor in the magnetic bearing of the embodiment of the application;

[0025] Figure 6 is a third structural schematic view of the bearing rotor in the magnetic bearing of the embodiment of the application;

[0026] Figure 7 is a fourth structural schematic view of the bearing rotor in the magnetic bearing of the embodiment of the application;

[0027] Figure 8 is a fifth structural schematic view of the bearing rotor in the magnetic bearing of the embodiment of the application;

[0028] Figure 9 is a sixth structural schematic view of the bearing rotor in the magnetic bearing of the embodiment of the application;

[0029] Figure 10 is a seventh structural schematic view of the bearing rotor in the magnetic bearing of the embodiment of the application.

[0030] The reference signs are as follows:

[0031] 1. Third iron core; 2. First coil; 3. Fixed frame; 4. Permanent magnet; 5. Mounting ring; 6. Second iron core; 7. Second coil; 8. First locking piece; 9. Fourth iron core; 10. Framework; 11. First iron core; 12. First rotor; 13. Axial magnetic circuit; 14. Permanent magnet bias magnetic circuit; 15. First radial magnetic circuit; 16. Second radial magnetic circuit; 17. First blocking piece; 18. Fifth iron core; 19. Second blocking piece; 20. Guard; 21. Magnetic isolation piece; 22. Second locking piece; 23. Bearing rotor. DETAILED DESCRIPTION

[0032] BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 to 10As shown, according to the embodiment of the present application, a magnetic suspension bearing is provided, comprising: an outer core, a first core 11 is sleeved in the outer core, a permanent magnet 4 is arranged between the first core 11 and the outer core, a bearing rotor 23 is sleeved in the first core 11, a first coil 2 is arranged on only one side of the first core 11 in the axial direction, the first coil 2 can generate a magnetic field when electrified, the first coil 2 and the permanent magnet 4 can generate an axial magnetic force on the bearing rotor 23 to make the bearing rotor 23 axially suspended, and a second coil 7 is wound on the first core 11, the second coil 7 can generate a magnetic field when electrified, and the second coil 7 and the permanent magnet 4 can generate a radial magnetic force on the bearing rotor 23 to make the bearing rotor 23 radially suspended. In the technical scheme, the first core 11 is preferably a silicon steel sheet, the two-side axial coil in the prior art is replaced by a single-side axial coil, the number of turns of the coil is increased, the first coil 2 and the permanent magnet 4 can generate an axial magnetic force on the bearing rotor 23 to make the bearing rotor 23 axially suspended, the space in the outer core is ensured, the structure is simpler, the implementation is easier, the overall structure of the bearing is more compact, the bearing size can be greatly reduced in the axial and radial directions, and the production cost is reduced. The axial magnetic circuit 13 generated by the axial first coil 2 is used to control the axial movement of the bearing rotor, the first coil 2 is electrified with a positive current, the axial magnetic circuit 13 is closed through the third core 1, the second core 6 and the bearing rotor 23, the permanent bias magnetic circuit 14 generated by the permanent magnet 4 is divided into two paths of left and right ends, the left end magnetic circuit is closed through the fourth core 9, the first core 11, the fifth core 18, the first stop piece 17, the third core 1 and the permanent magnet 4, the left end magnetic circuit of the bearing rotor 23 is consistent in direction, the magnetic fields are superposed, and the left end output is increased; the right end magnetic circuit is closed through the fourth core 9, the first core 11, the fifth core 18, the second stop piece 19, the second core 6 and the permanent magnet 4, the right end magnetic circuit of the bearing rotor 23 is opposite in direction, the magnetic fields are weakened, and the right end output is reduced, the bearing rotor 23 is subjected to a larger leftward force, and the first rotor 12 moves to the left, conversely, the bearing rotor 23 is subjected to a larger rightward force when the first coil 2 is electrified with a negative current, and the first rotor 12 moves to the right, so that the axial direction movement of the first rotor 12 is controlled by controlling the size and polarity of the current. The second coil 7 generates a radial first radial magnetic circuit 15, the coil is electrified with a positive current, the first radial magnetic circuit 15 is closed, and the bearing rotor 23 is subjected to a larger radial force when the first radial magnetic circuit 15 is closed, and the bearing rotor 23 moves to the left, conversely, the bearing rotor 23 is subjected to a larger radial force when the first radial magnetic circuit 15 is opened, and the bearing rotor 23 moves to the right, so that the radial direction movement of the bearing rotor 23 is controlled by controlling the size and polarity of the current. Figure 2As shown, the upper right path is closed clockwise, the lower left path is closed counterclockwise, the bias magnetic path generated by the permanent magnet 4 points to the center of the circle, the magnetic field of the upper left magnetic pole is weakened, the magnetic field of the lower right magnetic pole is enhanced, the bearing rotor 23 is subjected to a large force to the lower right; the second coil 7 generates a second radial magnetic path 16, the coil is connected to a positive current, the second radial magnetic path 16 is closed, and the magnetic field of the upper right magnetic pole is weakened under the influence of the magnetic field of the permanent magnet 4, and the magnetic field of the lower left magnetic pole is enhanced, the bearing rotor 23 is subjected to a large force to the lower left, and vice versa. By adjusting the size and polarity of the radial current, the radial movement of the bearing rotor 23 is controlled. Although the above-mentioned magnetic path has coupling phenomenon, the control method is simple and the control method is simple.

[0033] In a specific embodiment, the wall surface radially outside the first core 11 is a first wall surface, the wall surface radially inside the first core 11 is a second wall surface, the first coil 2 is located on the first core 11 close to the first wall surface, and the second coil 7 is located on the first core 11 close to the second wall surface.

[0034] In the technical solution, the first coil 2 is located on the first core 11 close to the first wall surface, and the second coil 7 is located on the first core 11 close to the second wall surface, which can form a more balanced magnetic path, effectively improve the stability of the magnetic circuit of the magnetic suspension bearing, and improve the working performance of the magnetic suspension bearing.

[0035] In a specific embodiment, the skeleton 10 is further provided, the skeleton 10 is fixed on the first core 11 through the first locking piece 8, and the first coil 2 is wound on the skeleton 10. Specifically, the skeleton 10 is U-shaped, the opening of the skeleton 10 faces the outer core, and one side of the skeleton 10 is fixed on the first core 11 through the first locking piece 8.

[0036] In the technical solution, the first locking piece 8 is preferably a screw, the skeleton 10 is assembled on the first core 11 by locking screws, the assembly is stable, the first coil 2 is wound on the skeleton 10, which can provide a control magnetic field to control the axial movement of the bearing rotor 23, the opening of the skeleton 10 faces the outer core, which is convenient for winding the coil, the opening of the skeleton 10 faces the outer core, and the assembly of the skeleton 10 is facilitated.

[0037] In a specific embodiment, the mounting ring 5 is further provided, the mounting ring 5 is sleeved in the outer core, the fourth core 9 is sleeved in the mounting ring 5, the first core 11 is sleeved in the fourth core 9, and the fourth core 9 and the outer core are provided with a gap, and the permanent magnet 4 is arranged in the gap. Specifically, the mounting ring 5 is located on the other side of the first core 11 in the axial direction, and the first coil 2 is located between the inner side of the fourth core 9 and the outer core in the axial direction.

[0038] In the technical solution, the fourth iron core 9 is used to facilitate the installation of the first iron core 11. The installation ring 5 is arranged on the other side of the first iron core 11 in the axial direction, so as to avoid the installation ring 5 from being arranged in a compact position of the skeleton 10 and affecting the installation of the skeleton 10. The installation ring 5 is used to facilitate the interference fit of the first iron core 11 and facilitate the gap fit of the fourth iron core 9 and the outer iron core for the permanent magnet 4. The first coil 2 is wound on the axial skeleton 10, and the axial skeleton 10 is locked on the first iron core 11 by the first locking member 8, so as to fix the first coil 2 and prevent the axial coil from being loose.

[0039] The segmented permanent magnet 4 is arranged on the second iron core 6 in the aligned notch, the N pole faces the center of the circle, so that the bias magnetic circuit points to the center of the circle, and then the permanent magnet fixing frame 3 is used to fix the permanent magnet, so that the permanent magnet is not easy to be loose. The S pole can also face the center of the circle, the bias magnetic circuit points to the circumference from the center, but it should be noted that the moving direction of the radial shaft is opposite to the direction described above. The three-degree-of-freedom magnetic bearing structure integrates the radial bearing and the axial bearing together, effectively reduces the bearing volume, shortens the length of the rotor, improves the critical speed of the rotor, saves the cost, and improves the performance of the compressor.

[0040] In a specific embodiment, the permanent magnet 4 is a segmented permanent magnet, which is uniformly distributed between the first iron core 11 and the outer iron core along the circumferential direction of the outer iron core. Specifically, as shown in Figure 3 The first iron core 11 and the outer iron core are provided with a fixing frame 3, and the fixing frame 3 can limit the displacement of the permanent magnet 4.

[0041] In the technical solution, the N pole of the permanent magnet 4 faces the center of the circle, so that the bias magnetic circuit points to the center of the circle. The segmented permanent magnet is easy to process, simple to magnetize, and convenient to install. The bias magnetic circuit is provided for the radial and axial directions at the same time, the number of permanent magnets is reduced, the cost is reduced, and the permanent magnet 4 is prevented from being loose by the fixing frame 3.

[0042] In a specific embodiment, the first iron core 11 is annular, the first iron core 11 has at least four radial magnetic poles, the second coil 7 is wound on the radial magnetic pole, and four second coils 7 are uniformly distributed on the first iron core 11. Each two second coils 7 are divided into a group, each two second coils 7 in the group are oppositely arranged, and each two second coils 7 in the group are connected in series. In the technical solution, the first iron core 11 has four magnetic poles, and four coils are wound thereon to provide a radial magnetic field to ensure the radial magnetic force and realize the control of the movement of the bearing rotor 23 in the radial direction.

[0043] In a specific embodiment, preferably, as shown in Figure 2As shown, the upper left coil is connected in series with the lower right coil, and the lower left coil is connected in series with the upper right coil, to control the movement of the rotating shaft in the radial direction, the outer core comprises a second core 6 and a third core 1, the second core 6 and the third core 1 are annular, the longitudinal section of the second core 6 and the third core 1 are C-shaped, the free end of the second core 6 on the radial outside is formed into a first surface, the free end of the third core 1 on the radial outside is formed into a second surface, and the first surface is opposite and connected with the second surface. In the technical scheme, the outer core is annular, the bearing rotor 23 is located between the C-shaped openings of the outer core 2, which can more conveniently arrange the components in the outer core 2, and is more conducive to forming a complete magnetic circuit and has better magnetic performance.

[0044] In a specific embodiment, referring to Figure 9 As shown, the magnetic suspension bearing can cooperate with the first rotor 12 of the motor, the bearing rotor 23 comprises a first stop piece 17, a fifth core 18 and a second stop piece 19, the first stop piece 17, the fifth core 18 and the second stop piece 19 are all sleeved on the first rotor 12, and the fifth core 18 is located between the first stop piece 17 and the second stop piece 19, and the first stop piece 17 and the second stop piece 19 cooperate to limit the fifth core 18. In the technical scheme, the first stop piece 17, the fifth core 18 and the second stop piece 19 are all in interference fit with the first rotor 12.

[0045] In a specific embodiment, referring to Figure 4 As shown, it further comprises a protective piece 20, the protective piece 20 is sleeved on the first rotor 12, and the first stop piece 17, the fifth core 18 and the second stop piece 19 are all sleeved on the protective piece 20.

[0046] In the technical scheme, the fifth core 18 is preferably a silicon steel sheet, the second core 6 and the third core 1 are aligned with the protective piece 20, the axial control magnetic circuit is from the second core 6, the protective piece 20 to the third core 1, the permanent magnet bias magnetic circuit is from the fifth core 18, the protective piece 20 to the second core 6, and from the fifth core 18, the protective piece 20 to the third core 1;

[0047] Referring to Figure 5 As shown, the second core 6 and the third core 1 are aligned with the first stop piece 17 and the second stop piece 19, the axial control magnetic circuit is from the second core 6, the second stop piece 19, the fifth core 18, the first stop piece 17 to the third core 1, and the permanent magnet bias magnetic circuit is from the fifth core 18, the second stop piece 19 to the second core 6, and from the fifth core 18, the first stop piece 17 to the third core 1;

[0048] In a specific embodiment, referring to Figure 6As shown, the first stopper 17 and the fifth core 18, the second stopper 19 and the fifth core 18 are provided with a magnetic isolation piece 21.

[0049] In the technical scheme, the first stopper 17 and the fifth core 18, the second stopper 19 and the fifth core 18 are provided with a magnetic isolation piece 21, the second core 6 and the third core 1 are aligned with the first stopper 17 and the second stopper 19, the axial control magnetic circuit is from the second core 6, the second stopper 19, the protection piece 20, the first stopper 17 to the third core 1, the permanent magnet bias magnetic circuit is from the fifth core 18, the protection piece 20, the first stopper 17 to the third core 1, and from the fifth core 18, the protection piece 20, the second stopper 19 to the second core 6.

[0050] Referring to Figure 7 As shown, the first stopper 17 and the second stopper 19 are L-shaped, the first stopper 17, the second stopper 19 and the fifth core 18 constitute a bearing rotor 23, and all of them adopt an interference fit;

[0051] Referring to Figure 8 As shown, the first stopper 17 is L-shaped, the first stopper 17, the second stopper 19 and the fifth core 18 constitute a bearing rotor 23, and all of them adopt an interference fit;

[0052] Referring to Figure 10 As shown, the second locking piece 22 is arranged in the first rotor 12 in the radial direction to the middle on the basis of the bearing rotor 23, the second locking piece 22 is preferably a screw, and the screw is locked in the radial direction, so as to ensure that the bearing rotor 23 is installed stably.

[0053] The application also provides a compressor comprising the magnetic suspension bearing.

[0054] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application. The above only describes the preferred embodiments of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be regarded as the protection scope of the present application.

Claims

1. A magnetic levitation bearing, characterized in that: include: An outer iron core is provided, and a first iron core (11) is provided inside the outer iron core. A permanent magnet (4) is provided between the first iron core (11) and the outer iron core. A bearing rotor (23) is provided inside the first iron core (11). A first coil (2) is provided on only one side of the first iron core (11) along the axial direction. The first coil (2) generates a magnetic field when energized. The first coil (2) and the permanent magnet (4) work together to generate an axial magnetic force on the bearing rotor (23) so that the bearing rotor (23) is axially suspended. A second coil (7) is wound on the first iron core (11). The second coil (7) generates a magnetic field when energized. The second coil (7) and the permanent magnet (4) work together to generate a radial magnetic force on the bearing rotor (23) so that the bearing rotor (23) is radially suspended. The magnetic levitation bearing also includes a mounting ring (5), which is sleeved inside the outer iron core. A fourth iron core (9) is sleeved inside the mounting ring (5), and the first iron core (11) is sleeved inside the fourth iron core (9). A gap is provided between the fourth iron core (9) and the outer iron core, and the permanent magnet (4) is disposed in the gap. The mounting ring (5) is located on the other side of the first iron core (11) in the axial direction, and the first coil (2) is located between the fourth iron core (9) and the outer iron core in the axial direction. The outer core includes a second core (6) and a third core (1). Both the second core (6) and the third core (1) are annular. The free end of the second core (6) located on the radial outer side is formed as a first surface, and the free end of the third core (1) located on the radial outer side is formed as a second surface. The first surface is opposite to and connected to the second surface.

2. The magnetic levitation bearing according to claim 1, characterized in that: The outer radial wall of the first iron core (11) is the first wall, the inner radial wall of the first iron core (11) is the second wall, the first coil (2) is located on the first iron core (11) near the first wall, and the second coil (7) is located on the first iron core (11) near the second wall.

3. The magnetic levitation bearing according to claim 1, characterized in that: It also includes a frame (10), which is fixed to the first iron core (11) by a first locking member (8), and the first coil (2) is wound on the frame (10).

4. The magnetic levitation bearing according to claim 3, characterized in that: One side of the frame (10) is fixed to the first iron core (11) by the first locking member (8).

5. The magnetic levitation bearing according to claim 1, characterized in that: The permanent magnet (4) is a segmented permanent magnet, and along the circumference of the outer iron core, the permanent magnet (4) is evenly distributed between the first iron core (11) and the outer iron core.

6. The magnetic levitation bearing according to claim 5, characterized in that: A fixing frame (3) is provided between the first iron core (11) and the outer iron core, and the fixing frame (3) can restrict the displacement of the permanent magnet (4).

7. The magnetic levitation bearing according to claim 1, characterized in that: The first iron core (11) is ring-shaped and has at least 4 radial magnetic poles. The second coil (7) is wound around the radial magnetic poles. The 4 second coils (7) are evenly distributed on the first iron core (11). Every two second coils (7) are divided into a group. The two second coils (7) in each group are arranged opposite each other, and the two second coils (7) in each group are connected in series.

8. The magnetic levitation bearing according to claim 1, wherein the magnetic levitation bearing can cooperate with the first rotor (12) of the motor, characterized in that: The bearing rotor (23) includes a first stop (17), a fifth iron core (18), and a second stop (19). The first stop (17), the fifth iron core (18), and the second stop (19) are all sleeved on the first rotor (12). The fifth iron core (18) is located between the first stop (17) and the second stop (19). The first stop (17) and the second stop (19) cooperate to limit the fifth iron core (18).

9. The magnetic levitation bearing according to claim 8, characterized in that: It also includes a protective component (20), which is sleeved on the first rotor (12), and the first stop (17), the fifth iron core (18), and the second stop (19) are all sleeved on the protective component (20).

10. The magnetic levitation bearing according to claim 8, characterized in that: A magnetic shielding component (21) is provided between the first stop (17) and the fifth iron core (18), and between the second stop (19) and the fifth iron core (18).

11. A compressor, characterized in that: The magnetic levitation bearing includes any one of claims 1 to 10.

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