Magnetic bearings, magnetic motors, compressors

Abstract

The present invention provides a magnetic suspension bearing, a magnetic suspension motor, and a compressor, wherein the magnetic suspension bearing comprises an outer iron core, an inner iron core in a mounting ring cavity of the outer iron core, the inner ring wall of the inner iron core is sleeved with a magnetic steel, the outer ring wall of the inner iron core is in contact with the cavity wall of the mounting ring cavity, and a radial gap is formed between the side of the magnetic steel away from the inner iron core and the thrust plate. According to the present invention, it is possible to effectively avoid excessive magnetic leakage of the magnetic steel, improve the utilization rate of the magnetic steel, and thus improve the overall axial output of the bearing, while also being able to reduce the volume of the magnetic steel under the premise of unchanged magnetic force demand, so that the bearing structure is compact and the cost is lower.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic suspension bearing manufacturing, and specifically relates to a magnetic suspension bearing, a magnetic suspension motor, and a compressor. Background Art

[0002] Magnetic bearing is a new type of magnetic machinery. It is a new type of high-performance bearing that uses magnetic force to suspend the rotor in space. Since there is no mechanical contact between the rotor and the stator, there is no mechanical friction. It has the characteristics of low loss, low noise, low vibration, no need for lubrication, low pollution to the environment, and long-term operation at ultra-high speed. Magnetic bearings have advantages that traditional bearings cannot match. When working, they can reach very high speeds, and dynamic parameters such as stiffness and damping can be easily adjusted by adjusting the controller parameters.

[0003] Magnetic bearings are mainly divided into active bearings, passive bearings and hybrid bearings. Figure 1 The hybrid axial bearing in the prior art is shown, which is mainly composed of an inner iron core, an outer iron core, a fixed frame, a coil, a magnetic steel, and a thrust plate. The inner iron core is fixed to the outer iron core by a positioning ring. This structure has the following main disadvantages:

[0004] (1) The magnetic field generated by the magnetic steel must first pass through the inner core, radial gap, thrust plate and then axial gap (working gap). There is magnetic leakage in each process (such as Figure 2 ), which results in low utilization of magnetic steel and greatly reduces the overall axial output of the bearing.

[0005] (2) The fixed frame and the inner iron core are matched by simple mechanical means and then ensured by varnish dipping. In a relatively harsh environment, there is a risk of loosening of the bearing. Summary of the invention

[0006] Therefore, the present invention provides a magnetic levitation bearing, a magnetic levitation motor, and a compressor to overcome the shortcomings of the prior art that the magnetic field generated by the magnetic steel seriously leaks magnetic flux before reaching the axial gap, resulting in low utilization of the magnetic steel and reducing the overall axial output of the bearing.

[0007] In order to solve the above problems, the present invention provides a magnetic levitation bearing, including an outer iron core and an inner iron core located in a mounting ring cavity of the outer iron core, the inner ring wall of the inner iron core is sleeved with magnetic steel, the outer ring wall of the inner iron core is in contact with the cavity wall of the mounting ring cavity, and a radial gap is formed between the side of the magnetic steel facing away from the inner iron core and the thrust plate.

[0008] Preferably, the magnetic steel is a ring.

[0009] Preferably, a cover plate is provided at the first axial end and / or the second axial end of the inner iron core, the cover plate has a cover plate center hole, the aperture of the cover plate center hole is smaller than the aperture of the center hole of the magnetic steel; and / or the magnetic steel is pasted on the inner ring wall of the inner iron core.

[0010] Preferably, a plurality of welding grooves extending along the axial direction are configured on the outer ring wall of the inner core, and the cover plate can be welded to the inner core through the welding grooves.

[0011] Preferably, a fixed frame is provided on the axial first end and the axial second end of the inner iron core, and the fixed frame includes a first plate body, a second plate body and a connecting plate body connected between the first plate body and the second plate body which are parallel to each other, and the first plate body, the connecting plate body and the second plate body form a U-groove structure for winding the coil, the outer diameter of the second plate body is larger than the outer diameter of the first plate body, and the second plate body in the fixed frame at the axial first end of the inner iron core is connected to the second plate body in the fixed frame at the axial second end of the inner iron core by threaded fasteners.

[0012] Preferably, the inner core is formed by stacking punching sheets, and the punching sheets are provided with connecting holes.

[0013] Preferably, the outer core includes a first core and a second core, and the first core is bolted to the second core.

[0014] Preferably, the outer annular wall of the inner core is connected to the mounting annular cavity by interference fit.

[0015] The present invention also provides a magnetic levitation motor, comprising a magnetic levitation bearing, wherein the magnetic levitation bearing is the above-mentioned magnetic levitation bearing.

[0016] The present invention also provides a compressor, comprising a magnetic suspension bearing, wherein the magnetic suspension bearing is the above-mentioned magnetic suspension bearing.

[0017] The present invention provides a magnetic levitation bearing, a magnetic levitation motor, and a compressor, in which the inner iron core is adjusted from a position between the magnetic steel and the thrust plate in the prior art to a side of the magnetic steel away from the thrust plate, thereby effectively avoiding excessive magnetic leakage of the magnetic steel, improving the utilization rate of the magnetic steel and thus improving the overall axial output of the bearing, while also being able to reduce the volume of the magnetic steel while keeping the magnetic force demand unchanged, making the bearing structure compact and lower in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the internal structure of a hybrid magnetic suspension bearing in the prior art;

[0019] Figure 2 for Figure 1Simulation diagram of magnetic circuit leakage of magnetic bearing in the figure;

[0020] Figure 3 A schematic diagram of the internal structure of a magnetic bearing according to an embodiment of the present invention;

[0021] Figure 4 for Figure 3 A partial enlarged view of the middle A;

[0022] Figure 5 for Figure 1 A schematic diagram of the three-dimensional structure of the inner iron core;

[0023] Figure 6 for Figure 1 A schematic diagram of the structure of the fixed skeleton in FIG.

[0024] Figure 7 A schematic diagram of a magnetic circuit of a magnetic bearing according to an embodiment of the present invention;

[0025] Figure 8 for Figure 3 Simulation diagram of magnetic circuit leakage of magnetic bearing in the figure;

[0026] Fig. 9 It is a schematic diagram of the assembly of some components of the magnetic bearing according to an embodiment of the present invention.

[0027] The reference numerals are:

[0028] 1. Outer iron core; 11. First iron core; 12. Second iron core; 2. Inner iron core; 21. Welding groove; 22. Connecting hole; 3. Magnetic steel; 4. Thrust plate; 5. Cover plate; 51. Center hole of cover plate; 6. Fixed frame; 61. First plate body; 62. Second plate body; 63. Connecting plate body; 64. Threaded fastener; 7. Coil. DETAILED DESCRIPTION

[0029] See also Figures 1 to 9 As shown, according to an embodiment of the present invention, a magnetic suspension bearing is provided, comprising an outer core 1, an inner core 2 in a mounting ring cavity of the outer core 1, the inner ring wall of the inner core 2 being sleeved with a magnetic steel 3, the outer ring wall of the inner core 2 being in contact with the cavity wall of the mounting ring cavity, and a radial gap being formed between the side of the magnetic steel 3 away from the inner core 2 and the thrust plate 4. In this technical solution, the inner core 2 is adjusted from the position between the magnetic steel and the thrust plate in the prior art to the side of the magnetic steel 3 away from the thrust plate 4, which can effectively avoid excessive magnetic leakage of the magnetic steel 3, improve the utilization rate of the magnetic steel and thus improve the overall axial output of the bearing, while also reducing the volume of the magnetic steel under the premise of unchanged magnetic force demand, making the bearing structure compact and lower in cost.

[0030] In some embodiments, the magnetic steel 3 is a ring body, that is, the magnetic steel 3 is a circular magnetic ring. In this case, the magnetic steel 3 can be connected to the inner ring wall of the inner core 2 by pasting, thereby reducing the difficulty of assembling the magnetic steel 3.

[0031] Furthermore, a cover plate 5 is provided at the axial first end and / or the axial second end of the inner iron core 2, and the cover plate 5 has a cover plate center hole 51, and the aperture of the cover plate center hole 51 is smaller than the aperture of the center hole of the magnetic steel 3. Preferably, the cover plate 5 is connected to the axial first end and the axial second end of the inner iron core 2. Since the aperture of the cover plate center hole 51 is smaller than the aperture of the center hole of the magnetic steel 3, it can prevent the thrust plate 4 from radially fluctuating and rubbing against the magnetic steel 3 when the thrust plate 4 is working, thereby protecting the magnetic steel 3.

[0032] In some embodiments, a plurality of welding grooves 21 extending axially thereof are constructed on the outer ring wall of the inner core 2, and the cover plate 5 can be welded to the inner core 2 through the welding grooves 21, which can further enhance the connection strength between the inner core 2 and the cover plate 5, and is particularly suitable for the case where the inner core 2 is formed by stacking punching sheets.

[0033] In some embodiments, a fixed skeleton 6 is provided on the axial first end and the axial second end of the inner iron core 2, and the fixed skeleton 6 includes a first plate body 61 and a second plate body 62 which are parallel to each other, and a connecting plate body 63 connected between the first plate body 61 and the second plate body 62. The first plate body 61, the connecting plate body 63, and the second plate body 62 form a U-groove structure for winding the coil 7. The outer diameter of the second plate body 62 is larger than the outer diameter of the first plate body 61. The second plate body 62 in the fixed skeleton 6 at the axial first end of the inner iron core 2 and the second plate body 62 in the fixed skeleton 6 at the axial second end of the inner iron core 2 are connected by threaded fasteners 64, thereby effectively ensuring the assembly stability between the fixed skeleton 6 and the inner iron core 2, and then ensuring the overall structural stability of the bearing.

[0034] It can be understood that the punching sheet is configured with a connecting through hole 22 to ensure that the threaded fastener 64 can pass through and connect, thereby improving the overall structural stability of the inner core 2.

[0035] In some embodiments, the outer core 1 includes a first core 11 and a second core 12, and the first core 11 is bolted to the second core 12. The outer ring wall of the inner core 2 is connected to the mounting ring cavity by interference fit.

[0036] Figure 7The figure shows a schematic diagram of the magnetic circuit of the magnetic bearing of the embodiment of the invention, wherein a is the bias magnetic field path provided by the magnetic steel 3, specifically: magnetic steel 3-radial gap-thrust plate 4-axial air gap-outer iron core 1-inner iron core 2-magnetic steel 3; b is the control magnetic field path provided by the coil, specifically: thrust plate 4-axial air gap-outer iron core 1-axial air gap-thrust plate 4.

[0037] Figure 8 This is a simulation diagram of magnetic leakage of the magnetic circuit of the magnetic bearing using the technical solution of the present invention. Figure 2 By comparing the simulation diagram of magnetic circuit leakage of the magnetic bearing in the prior art, it can be seen that the magnetic leakage phenomenon of the magnetic steel is significantly improved. According to relevant data, the magnetic leakage rate of the magnetic steel is reduced from the original 44% to 12%.

[0038] Fig. 9 Schematic diagram of the assembly of some parts of the magnetic bearing, the specific assembly process is: the fixed frame 6 is wound and dipped in paint to realize the coil frame production, the inner iron core 2 is pressed by silicon steel sheets; the magnetic steel is annular magnetic steel, which is adhered to the inner ring wall of the inner iron core 2 by magnetic force, ensuring that the upper and lower end faces of the magnetic steel 3 are flush with the upper and lower end faces of the inner iron core (that is, corresponding to the axial first end and the axial second end of the inner iron core 2); the outer diameter of the cover plate 5 is aligned with the outer diameter of the inner iron core 2, and the through hole of the skeleton coil frame is aligned with the through hole of the cover plate 5 and the inner iron core 2, and the threaded fastener 64 is used. The inner axial core assembly is fixed and locked, and the cover plate 5 is welded to the silicon steel sheet through the welding groove 21 to further improve the overall stability of the inner axial assembly; at this time, the outer core 1 is heated, and the inner axial core assembly formed in the previous step is heat-fitted with the first core 11 in the outer core 1 to realize the rear axial bearing assembly; when assembling the whole machine, the second core 12 in the outer core 1 is first assembled with the compressor housing, and then the rotating shaft equipped with the thrust plate 4 is inserted into the stator, and finally the threaded holes on the first core 11 and the second core 12 are aligned and fastened by screws.

[0039] According to an embodiment of the present invention, there is further provided a magnetic levitation motor, comprising a magnetic levitation bearing, wherein the magnetic levitation bearing is the magnetic levitation bearing described above.

[0040] According to an embodiment of the present invention, there is further provided a compressor, comprising a magnetic bearing, wherein the magnetic bearing is the magnetic bearing described above.

[0041] 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.

[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. The above are only preferred embodiments of the present invention. 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 invention, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A magnetic bearing, characterized in that: The invention comprises an outer iron core (1), an inner iron core (2) located in a mounting annular cavity of the outer iron core (1), the inner annular wall of the inner iron core (2) being sleeved with a magnetic steel (3), the outer annular wall of the inner iron core (2) being in contact with and connected to the cavity wall of the mounting annular cavity, and a radial gap being formed between a side of the magnetic steel (3) facing away from the inner iron core (2) and a thrust plate (4); the magnetic steel (3) being a ring body; a cover plate (5) being provided at the axial first end and / or the axial second end of the inner iron core (2), the cover plate (5) having a cover plate center hole (51), the aperture of the cover plate center hole (51) being smaller than the aperture of the center hole of the magnetic steel (3).

2. The magnetic bearing according to claim 1, characterized in that: The magnetic steel (3) is adhered to the inner ring wall of the inner iron core (2).

3. The magnetic bearing according to claim 1, characterized in that: The outer ring wall of the inner iron core (2) is provided with a plurality of welding grooves (21) extending along the axial direction thereof, and the cover plate (5) can be welded to the inner iron core (2) through the welding grooves (21).

4. The magnetic bearing according to claim 3, characterized in that: A fixed frame (6) is provided at the first axial end and the second axial end of the inner iron core (2); the fixed frame (6) comprises a first plate (61), a second plate (62) and a connecting plate (63) connected between the first plate (61) and the second plate (62), the first plate (61), the connecting plate (63) and the second plate (62) forming a U-groove structure for winding a coil (7); the outer diameter of the second plate (62) is greater than the outer diameter of the first plate (61); the second plate (62) in the fixed frame (6) at the first axial end of the inner iron core (2) and the second plate (62) in the fixed frame (6) at the second axial end of the inner iron core (2) are connected via a threaded fastener (64).

5. The magnetic bearing according to claim 4, characterized in that: The inner iron core (2) is formed by stacking punching sheets, and the punching sheets are provided with connecting through holes (22).

6. The magnetic bearing according to claim 1, characterized in that: The outer iron core (1) comprises a first iron core (11) and a second iron core (12), and the first iron core (11) and the second iron core (12) are bolted together.

7. The magnetic bearing according to claim 1, characterized in that: The outer annular wall of the inner iron core (2) is connected to the mounting annular cavity by interference fit.

8. A magnetic levitation motor, comprising a magnetic levitation bearing, characterized in that: The magnetic bearing is the magnetic bearing according to any one of claims 1 to 7.

9. A compressor, comprising a magnetic bearing, characterized in that: The magnetic bearing is the magnetic bearing according to any one of claims 1 to 7.

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