A low-loss radial magnetic bearing system

Abstract

The present invention discloses a low-loss radial magnetic suspension bearing system, the structure of which includes an upper stator pressure ring, a lower stator pressure ring, a stator magnetic conductive ring, an upper stator assembly, a lower stator assembly and a rotor assembly. The upper stator assembly and the lower stator assembly have the same structure, the magnetic field polarity of the teeth of the upper stator assembly is N pole, the magnetic field polarity of the teeth of the lower stator assembly is S pole, the inner rings of the teeth of the stators in the magnetic bearings of the upper stator assembly and the lower stator assembly are closed, and each tooth is provided with at least two layers of coil windings. The winding form of the bearing system improves the coverage rate of the enameled wire for the magnetic bearing stator slots, and the process is easy to implement, which can optimize the performance and facilitate mass production. Since the inner ring of the stator tooth pole is also closed, the magnetic field distribution inside the rotor is more uniform, and no sudden change in magnetic field strength will occur at the position where the tooth pole is not closed.

Description

Technical Field

[0001] The invention relates to the field of magnetic suspension bearings, in particular to a low-loss radial magnetic suspension bearing system. Background Art

[0002] For the magnetic levitation motor system, the compactness of the magnetic levitation bearing system and the processability of the system are both worth deep optimization. The conventional magnetic bearing rotor has a stator magnetic pole magnetic field direction distribution of NSSNNSSN, and the internal magnetic field direction changes suddenly during the rotation of the rotor, causing increased iron loss.

[0003] The thicker the winding used in the magnetic bearing stator, the smaller the winding resistance, and the smaller the heat loss generated under rated conditions. Due to the manufacturing process, the traditional magnetic bearing stator cannot use enameled wire to cover all the slots to reduce the winding resistance and reduce the copper loss of the system. The inner circular teeth of the traditional magnetic bearing stator are not closed, and the magnetic fields of the eight tooth poles are arranged in NSSNNSSN. The direction of the internal magnetic field of the silicon steel sheet of the bearing rotor alternates during rotation, and the direction of the NS magnetic field changes back and forth, which easily generates high hysteresis loss and eddy current loss on the rotor. Summary of the invention

[0004] The purpose of the present invention is to provide a low-loss radial magnetic bearing system to solve the problems of low stator slot utilization, large coil resistance, and severe heating after power-on operation of magnetic bearings. The system has low process difficulty, is easy to mass produce, has high stator slot coverage, and reduces system losses.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a low-loss radial magnetic suspension bearing system, whose structure includes an upper stator pressure ring, a lower stator pressure ring, a stator magnetic conductive ring, an upper stator assembly, a lower stator assembly and a rotor assembly, the rotor assembly is coaxial with the upper stator assembly and the lower stator assembly, the upper stator pressure ring, the upper stator assembly, the stator magnetic conductive ring, the lower stator assembly and the lower stator pressure ring are fixed in series from top to bottom by fasteners, the upper stator assembly and the lower stator assembly have the same structure, the tooth magnetic field of the upper stator assembly is an N pole, the tooth magnetic field of the lower stator assembly is an S pole, the inner rings of the teeth of the stators in the magnetic bearings of the upper stator assembly and the lower stator assembly are closed, and each tooth is provided with at least two layers of coil windings.

[0006] Furthermore, the upper stator assembly includes an outer stator of a magnetic bearing, an inner stator of a magnetic bearing, a coil insulation frame assembly and a coil winding assembly. The inner stator of the magnetic bearing is movably connected to the inner ring of the outer stator of the magnetic bearing. A coil insulation frame assembly is provided on the tooth portion of the inner stator of the magnetic bearing, and the coil winding assembly is arranged inside the coil insulation frame assembly.

[0007] Furthermore, a plurality of inner stator teeth are evenly arranged on the outer circumference of the closed inner ring of the inner stator of the magnetic bearing, and a buckle for clamping with the outer stator of the magnetic bearing is respectively arranged at the free end of each inner stator tooth.

[0008] Furthermore, the coil insulation skeleton assembly includes a skeleton body and coil slots. The skeleton body is sleeved with the teeth of the stator in the magnetic bearing. The coil slots for winding the coil winding are located between adjacent partitions of the skeleton body.

[0009] Furthermore, the number of the coil slots is at least two.

[0010] Furthermore, the rotor assembly includes a rotor sleeve, a rotor magnetic ring, a magnetic bearing upper rotor and a magnetic bearing lower rotor. The rotor sleeve is coaxial with the inner stators of the upper stator assembly and the lower stator assembly. The rotor magnetic ring is sleeved on the middle part of the rotor sleeve and has an interference fit. The magnetic bearing upper rotor and the magnetic bearing lower rotor are respectively sleeved on the upper and lower ends of the rotor sleeve and have an interference fit. The magnetic bearing upper rotor, the rotor magnetic ring and the magnetic bearing lower rotor are tightly fitted axially.

[0011] Furthermore, the inner ring of the outer stator of the magnetic bearing is provided with a slot corresponding to the teeth of the inner stator.

[0012] Beneficial effects of the present invention:

[0013] The winding form of the bearing system of the present invention improves the coverage rate of the enameled wire for the stator slots of the magnetic bearing, and at the same time, the process is easy to implement, which can not only optimize the performance, but also facilitate mass production. Since the magnetic field of the stator tooth pole presents an NNNNNNNN arrangement at the upper end and an SSSSSSSS arrangement at the lower end, the magnetic field of the bearing rotor will not alternate during rotation, which greatly reduces the eddy current loss. In addition, the inner ring of the stator tooth pole is also closed, so that the magnetic field distribution inside the rotor is more uniform, and no sudden changes in the magnetic field strength will occur at the position where the tooth pole is not closed. The sudden changes in the magnetic field strength and magnetic field direction will increase the hysteresis loss and eddy current loss of the magnetic bearing rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 An axonometric view of the present invention as a whole;

[0015] Figure 2 It is an exploded view of the installation of the present invention as a whole;

[0016] Figure 3 for Figure 1 Schematic diagram of the internal structure;

[0017] Figure 4 for Figure 1 The main view of

[0018] Figure 5 for Figure 4 AA section view;

[0019] Figure 6 is an exploded view of the upper stator assembly;

[0020] Figure 7 It is a schematic diagram of the structure of the coil insulation skeleton;

[0021] Figure 8 It is a schematic diagram of the structure of the outer stator of the magnetic bearing;

[0022] Fig. 9 It is a schematic diagram of the structure of the stator in the magnetic bearing;

[0023] Fig.10 An exploded view of the rotor assembly.

[0024] In the figure:

[0025] 1 upper stator pressure ring, 2 rotor assembly, 21 rotor sleeve, 22 rotor magnetic ring, 23 magnetic bearing upper rotor, 24 magnetic bearing lower rotor, 3 upper stator assembly, 31 magnetic bearing outer stator, 311 outer stator body, 312 slot, 32 magnetic bearing inner stator, 321 inner stator tooth, 322 buckle, 323 through hole, 33 coil insulation skeleton assembly, 331 skeleton body, 332 coil slot, 34 coil winding assembly, 4 lower stator assembly, 5 lower stator pressure ring, 6 stator magnetic ring, 7 fastener. DETAILED DESCRIPTION

[0026] A low-loss radial magnetic bearing system of the present invention is described in detail below with reference to the accompanying drawings.

[0027] like Figures 1 to 10As shown, a low-loss radial magnetic suspension bearing system of the present invention comprises an upper stator pressure ring 1, a lower stator pressure ring 5, a stator magnetic ring 6, an upper stator assembly 3, a lower stator assembly 4 and a rotor assembly 2, wherein the rotor assembly 2 is coaxial with the upper stator assembly 3 and the lower stator assembly 4, and the upper stator pressure ring 1, the upper stator assembly 3, the stator magnetic ring 6, the lower stator assembly 4 and the lower stator pressure ring 5 are fixed in series from top to bottom by a fastener 7, and the fastener 7 can be a screw, and one end of the screw passes through the upper stator pressure ring 1, the upper stator assembly 3, the stator magnetic ring 6, the lower stator assembly 4 and the lower stator pressure ring 5 in sequence to form a whole, forming a magnetic bearing stator assembly. The upper stator assembly 3 and the lower stator assembly 4 have the same structure, the magnetic field polarity of the teeth of the upper stator assembly 3 is N pole, and the magnetic field polarity of the teeth of the lower stator assembly 4 is S pole, and the magnetic field of the bearing rotor does not alternate during rotation, which greatly reduces eddy current loss. The inner rings of the teeth of the stators in the magnetic bearings of the upper stator assembly and the lower stator assembly are closed, and each tooth is provided with at least two layers of coil windings. The closed inner ring makes the magnetic field inside the rotor more uniform, and does not produce a sudden change in magnetic field strength at the position where the teeth are not closed. The sudden change in magnetic field strength and magnetic field direction will increase the hysteresis loss and eddy current loss of the magnetic bearing rotor.

[0028] like Figure 6 As shown, the upper stator assembly 3 includes a magnetic bearing outer stator 31, a magnetic bearing inner stator 32, a coil insulation skeleton assembly 33 and a coil winding assembly 34. The magnetic bearing inner stator 32 is movably buckled with the inner ring of the magnetic bearing outer stator 31. The teeth of the magnetic bearing inner stator 32 are provided with a coil insulation skeleton assembly 33. The coil insulation skeleton assembly is composed of a plurality of skeleton bodies respectively sleeved with the corresponding teeth. The coil winding assembly 34 is arranged in the coil insulation skeleton assembly 33. The coil winding assembly is wound with a plurality of coils corresponding to the position and number of each skeleton body. The outer circumference of the closed inner ring of the magnetic bearing inner stator 32 is evenly provided with a plurality of inner stator teeth 321. The free end of each inner stator tooth 321 is respectively provided with a buckle 322 for buckling with the magnetic bearing outer stator 31. As shown Fig. 9 As shown, eight inner stator teeth 321 are evenly arranged on the outer circumference of the closed inner ring of the magnetic bearing inner stator 32, and the free ends of the eight inner stator teeth 321 are all provided with buckles 322, and the magnetic fields of the eight inner stator teeth are all N poles. The closed inner ring outer circumference of the magnetic bearing inner stator of the lower stator assembly 4 is also evenly arranged with eight inner stator teeth, and the magnetic fields of the eight inner stator teeth are all S poles.

[0029] The coil insulation skeleton 33 assembly includes a skeleton body 331 and a coil slot 332. The skeleton body 331 is sleeved with the tooth portion of the stator 32 in the magnetic bearing, and the adjacent partitions of the skeleton body 331 are coil slots 332 for winding the coil winding. The number of the coil slots 332 is at least two, and the specific number can be set differently according to the use requirements. The coil is wound in the coil slot, and the winding diameter of each coil slot is different. For the magnetic bearing stator, the thicker the winding used, the smaller the winding resistance, and the smaller the heat loss generated under the rated working conditions. Due to the manufacturing process reasons, the traditional magnetic suspension bearing stator cannot use enameled wire to cover all the slots to reduce the winding resistance and reduce the copper loss of the system. The present invention improves the coverage rate of the enameled wire for the magnetic bearing stator slot by setting an insulating skeleton, and the process is easy to implement, which can not only optimize the performance, but also facilitate mass production.

[0030] like Fig.10 As shown, the rotor assembly 2 includes a rotor sleeve 21, a rotor magnetic ring 22, a magnetic bearing upper rotor 23 and a magnetic bearing lower rotor 24. The rotor sleeve 21 is coaxial with the inner stator of the upper stator assembly 3 and the lower stator assembly 1. The rotor magnetic ring 22 is sleeved and interference fit with the middle of the rotor sleeve 21. The magnetic bearing upper rotor 23 and the magnetic bearing lower rotor 24 are sleeved and interference fit with the upper and lower ends of the rotor sleeve 21 respectively. The magnetic bearing upper rotor 23, the rotor magnetic ring 22 and the magnetic bearing lower rotor 24 are tightly fitted axially. The magnetic bearing upper rotor 23 and the magnetic bearing lower rotor 24 are both silicon steel sheets, and the rotor sleeve 21 and the rotor magnetic ring 22 are magnetic carbon steel.

[0031] The inner circle of the outer stator body 311 of the magnetic bearing outer stator 31 is provided with a slot 312 corresponding to the inner stator tooth portion. When the inner stator and the outer stator are installed, the buckle 322 at the end of the tooth portion is engaged with the slot 312, so that the inner stator is embedded in the outer stator, ensuring the firmness of the assembly.

[0032] The magnetic field distribution during operation is shown in the figure above:

[0033] The magnetic field lines of the upper stator flow in from the outside and point inward, and the magnetic field distribution of the upper tooth pole is NNNNNNNN. The magnetic field lines of the lower stator flow out from the inside and point outward, and the magnetic field distribution of the lower tooth pole is SSSSSSSS. The magnetic field direction of the rotor will not change suddenly during the rotation process. This reduces the hysteresis loss and eddy current loss of the rotor material itself.

[0034] Working principle:

[0035] like Figure 2As shown, the upper stator assembly 3 includes 8 teeth, and every two teeth form an N-pole magnetic force generator in one direction. The lower stator assembly 4 includes 8 teeth, and every two teeth form an S-pole magnetic force generator in one direction. The four teeth corresponding to the upper and lower ends together form a magnetic force generator in one direction of the system. The magnetic force direction is the four directions X+X-Y+Y- of the two-dimensional plane coordinate system. When the magnetic force in the X+ direction is required, the two teeth at the upper end and the two teeth at the lower end form the magnetic field distribution shown in the figure, as shown in FIG. Figure 5 As shown in the figure, a larger current is passed through the upper part, which generates a larger magnetic flux density, and a larger magnetic flux density generates a larger magnetic force. No current or less current is passed through the lower part, which forms a smaller magnetic density and generates a smaller magnetic force. The unbalanced magnetic force forms a magnetic force in one direction, so that the rotor can adjust its position during rotation according to the change in the size of the magnetic force, so as to achieve the function and purpose of the magnetic suspension bearing.

[0036] The above description is only used to illustrate some principles of the present invention. This specification is not intended to limit the present invention to the specific structure and application scope shown and described. Therefore, all corresponding modifications and equivalents that may be used belong to the patent scope applied for by the present invention.

[0037] Except for the technical features described in the specification, the other technical features are known technologies to those skilled in the art.

Claims

1. A low-loss radial magnetic bearing system, comprising an upper stator pressure ring, a lower stator pressure ring, a stator magnetic ring, an upper stator assembly, a lower stator assembly and a rotor assembly, wherein the rotor assembly is coaxial with the upper stator assembly and the lower stator assembly, and the upper stator pressure ring, the upper stator assembly, the stator magnetic ring, the lower stator assembly and the lower stator pressure ring are fixed in series from top to bottom by fasteners, characterized in that: The upper stator assembly and the lower stator assembly have the same structure, the magnetic field polarity of the teeth of the upper stator assembly is N pole, the magnetic field polarity of the teeth of the lower stator assembly is S pole, the inner rings of the teeth of the stators in the magnetic bearings of the upper stator assembly and the lower stator assembly are closed, and each tooth is provided with at least two layers of coil windings; The upper stator assembly comprises an outer stator of a magnetic bearing, an inner stator of a magnetic bearing, a coil insulation skeleton assembly and a coil winding assembly, the inner stator of the magnetic bearing is movably buckled with the inner ring of the outer stator of the magnetic bearing, a coil insulation skeleton assembly is provided on the teeth of the inner stator of the magnetic bearing, and the coil winding assembly is provided in the coil insulation skeleton assembly; The outer circumference of the closed inner ring of the inner stator of the magnetic bearing is evenly provided with a plurality of inner stator teeth, and the free end of each inner stator tooth is respectively provided with a buckle for clamping with the outer stator of the magnetic bearing; The rotor assembly includes a rotor sleeve, a rotor magnetic ring, a magnetic bearing upper rotor and a magnetic bearing lower rotor. The rotor sleeve is coaxial with the inner stators of the upper stator assembly and the lower stator assembly. The rotor magnetic ring is sleeved on the middle part of the rotor sleeve and has an interference fit. The magnetic bearing upper rotor and the magnetic bearing lower rotor are respectively sleeved on the upper and lower ends of the rotor sleeve and have an interference fit. The magnetic bearing upper rotor, the rotor magnetic ring and the magnetic bearing lower rotor are tightly fitted axially.

2. A low-loss radial magnetic bearing system according to claim 1, characterized in that: The coil insulation skeleton assembly comprises a skeleton body and coil slots. The skeleton body is sleeved with the teeth of the stator in the magnetic bearing. The coil slots for winding the coil winding are located between adjacent partitions of the skeleton body.

3. A low-loss radial magnetic bearing system according to claim 2, characterized in that: The number of the coil slots is at least two.

4. A low-loss radial magnetic bearing system according to claim 1, characterized in that: The inner ring of the outer stator of the magnetic bearing is provided with a clamping groove corresponding to the teeth of the inner stator.

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