Five-degree-of-freedom magnetic levitation bearing and motor

Abstract

The application provides a five-degree-of-freedom magnetic suspension bearing and motor, wherein the five-degree-of-freedom magnetic suspension bearing comprises a magnetic conducting sleeve, the axial two ends of the magnetic conducting sleeve are respectively provided with a radial magnetic conducting ring extending radially inward along the magnetic conducting ring, and the inner ring wall of each radial magnetic conducting ring is provided with a first magnetic steel ring arranged concentrically; the rotor comprises a thrust part and shaft end sections on the axial two sides of the thrust part, and each shaft end section is respectively inserted into the through hole of the first magnetic steel ring. The first magnetic steel ring is arranged at the position of the two end faces of the thrust part of the rotor, and the first magnetic steel ring can improve the magnetic field intensity in the axial air gap between the radial magnetic conducting ring and the thrust part, thereby improving the axial support stiffness of the magnetic suspension bearing and further improving the axial load of the magnetic suspension bearing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of magnetic suspension bearing design, and particularly relates to a five-degree-of-freedom magnetic suspension bearing and motor. BACKGROUND

[0002] The magnetic suspension bearing has the characteristics of no mechanical contact, no lubrication, high speed, high precision, long service life and high reliability, and is widely used in the field of high speed and super high speed.

[0003] The existing magnetic suspension bearing structure is composed of a radial bearing and an axial bearing, and the five degrees of freedom of the rotor are suspended by cooperation of the radial bearing and the axial bearing. Figure 1 As shown in the figure, the radial bearing is composed of five components, namely, a radial winding (1), a magnetic conducting ring (2), a radial magnetic steel (3), an iron core positioning ring (4) and a radial iron core (5), and the axial bearing is composed of five components, namely, a front axial iron core (6), a rear axial iron core (7), an axial magnetic steel (10), an axial iron core (8) and an axial winding (9). The rear three-degree-of-freedom magnetic bearing and the front two-degree-of-freedom radial magnetic bearing of the magnetic suspension bearing with such a structure are arranged along the axis of the rotor in the axial direction, and the axial space volume is large, the length of the rotor is long, the deflection of the rotor is large, the natural frequency is small, and the limit speed of the rotor is low; the rear radial bearing and the axial bearing each use a set of magnetic steel, and there are radial air gaps and axial air gaps, the magnetic field strength of the control magnetic field and the bias magnetic field of the magnetic steel in the axial air gap is low, and there are the disadvantages of low support stiffness and low axial load; the rear radial suspension system and the front radial suspension are independently arranged, and two sets of radial magnetic steels are used for the suspension system, so that the cost of the magnetic suspension product is increased.

[0004] Based on the disadvantages of the prior art, the patent with the application number CN201610112198.1 discloses a self-adjusting five-degree-of-freedom magnetic bearing, wherein the radial iron core and the axial iron core share a set of permanent magnet rings, and the radial magnetic bearing and the axial magnetic bearing are integrated, which can effectively shorten the length of the shaft, but the magnetic field strength of the axial bias magnetic field in the axial air gap is low, and there are still the disadvantages of low support stiffness and low bearing load, based on which the application is proposed. SUMMARY

[0005] Therefore, the application provides a five-degree-of-freedom magnetic suspension bearing and motor, which can solve the technical problems of low magnetic field strength in the axial air gap of the five-degree-of-freedom magnetic suspension bearing in the prior art, low support stiffness and low bearing load.

[0006] In order to solve the above problems, the application provides a five-degree-of-freedom magnetic suspension bearing, which comprises:

[0007] The magnetic sleeve has two radial magnetic rings respectively at the axial ends of the magnetic sleeve, each of the radial magnetic rings has a first magnetic steel ring concentrically arranged on the inner wall of the radial magnetic ring;

[0008] The rotor includes a thrust portion and shaft end sections at the axial sides of the thrust portion, each of the shaft end sections is inserted into the through hole of the first magnetic steel ring.

[0009] In some embodiments,

[0010] Each of the through holes of the first magnetic steel ring is further provided with a first axial magnetic ring, each of the shaft end sections is rotatably inserted into the through hole of the first axial magnetic ring, and the outer edge end surface of the thrust portion is between the two first axial magnetic rings.

[0011] In some embodiments,

[0012] The inner wall of each of the radial magnetic rings has a second axial magnetic ring extending along the axial direction of the rotor, the two second axial magnetic rings are protrudingly arranged in the direction close to each other, and the outer edge end surface of the thrust portion is between the two second axial magnetic rings.

[0013] In some embodiments,

[0014] Corresponding to the same end of the rotor, the minimum distance between the end surfaces of the first axial magnetic ring, the second axial magnetic ring and the end surface of the thrust portion is less than the minimum distance between the end surface of the first magnetic steel ring and the end surface of the thrust portion.

[0015] In some embodiments,

[0016] Each of the axial control coils is wound around each of the second axial magnetic rings.

[0017] In some embodiments, the five-degree-of-freedom magnetic levitation bearing further includes:

[0018] A second magnetic steel ring is concentrically arranged on the inner wall of the cylinder of the magnetic sleeve;

[0019] A stator core is concentrically arranged on the inner wall of the second magnetic steel ring, has a stator yoke ring and a plurality of stator teeth uniformly and spacedly arranged along the circumferential direction of the stator yoke ring, and has two groups, and the two groups of stator cores are spacedly arranged along the axial direction of the rotor;

[0020] Radial control windings are wound around each of the stator teeth.

[0021] In some embodiments,

[0022] Each of the stator cores has four stator teeth, and the radial control windings are wound on two stator teeth that are symmetric about the center of the stator core in the axial projection of the rotor.

[0023] In some embodiments,

[0024] Each of the stator cores has four stator teeth, and the radial control windings are wound on two stator teeth that are symmetric about the center of the stator core in the axial projection of the rotor.

[0025] In some embodiments,

[0026] The first magnetic steel ring and the second magnetic steel ring are both radially magnetized.

[0027] The application also provides an electric machine comprising the five-degree-of-freedom magnetic suspension bearing.

[0028] The application provides a five-degree-of-freedom magnetic suspension bearing and an electric machine, wherein a first magnetic steel ring is arranged at each of the two end surfaces of the thrust portion of the rotor, and the first magnetic steel ring can improve the magnetic field strength in the axial air gap between the radial magnetic conducting ring and the thrust portion, thereby improving the axial support stiffness of the magnetic suspension bearing and further improving the axial load of the magnetic suspension bearing. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Fig. 1 is a schematic view of the internal structure of a magnetic suspension bearing in the prior art;

[0030] Figure 2 Fig. 2 is a schematic view of the internal structure of a five-degree-of-freedom magnetic suspension bearing according to an embodiment of the application (axial section);

[0031] Figure 3 Fig. 3 is a schematic view of the magnetic circuit in the state shown in Fig. 2; Figure 2 Fig. 4 is a schematic view of the magnetic circuit in the state shown in Fig. 3;

[0032] Figure 4 Fig. 5 is a side view (i.e., axial projection) of the five-degree-of-freedom magnetic suspension bearing according to an embodiment of the application; Figure 2 Fig. 6 is a side view (i.e., axial projection) of the five-degree-of-freedom magnetic suspension bearing according to an embodiment of the application;

[0033] Figure 5 Fig. 7 is an exploded view of the five-degree-of-freedom magnetic suspension bearing according to an embodiment of the application.

[0034] The reference signs are as follows:

[0035] 1, radial winding; 2, magnetic conducting ring; 3, radial magnetic steel; 4, core positioning ring; 5, radial core; 6, front axial core; 7, rear axial core; 8, axial core; 9, axial winding; 10, axial magnetic steel;

[0036] 11, magnetic sleeve; 111, radial magnetic ring; 112, second axial magnetic ring; 12, rotor; 121, thrust portion; 122, shaft end section; 13, first magnetic steel ring; 14, first axial magnetic ring; 15, axial control coil; 16, stator core; 161, stator yoke ring; 162, stator tooth; 17, radial control winding; 18, second magnetic steel ring. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions will be described clearly and completely below with reference to the specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0038] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in other than the order illustrated or described herein.

[0039] With reference to Figure 1 and Figure 5 shown, according to an embodiment of the present application, a five-degree-of-freedom magnetic levitation bearing is provided, comprising:

[0040] The magnetic sleeve 11 is made of a magnetic material, and in specific applications, it is assembled in a housing or bearing seat made of a magnetic material. In order to facilitate the assembly of the components inside, it can be designed as two separate structures connected together. The axial ends of the magnetic sleeve 11 each have a radial magnetic ring 111 extending radially inward along the magnetic sleeve 11. The inner ring wall of each radial magnetic ring 111 has a first magnetic steel ring 13 arranged concentrically thereon. The first magnetic steel ring 13 can be a permanent magnet.

[0041] The rotor 12 includes a thrust portion 121 and shaft end sections 122 on both axial sides of the thrust portion 121. Each shaft end section 122 is inserted into the through hole of the first magnetic steel ring 13, so that the two end faces of the thrust portion 121 of the rotor 12 are between the two first magnetic steel rings 13.

[0042] The technical scheme is characterized in that the first magnetic steel rings 13 are arranged at the two end surfaces of the thrust portion 121 of the rotor 12, and the first magnetic steel rings 13 can improve the magnetic field strength in the axial air gap formed between the radial magnetic conducting ring 111 and the thrust portion 121, thereby improving the axial support stiffness of the magnetic suspension bearing and further improving the axial load of the magnetic suspension bearing.

[0043] In a feasible embodiment, the first magnetic steel rings 13 are assembled on the inner ring wall of the radial magnetic conducting ring 111 in an interference fit.

[0044] In some embodiments,

[0045] The through hole of each first magnetic steel ring 13 is further provided with a first axial magnetic conducting ring 14, each axial end section 122 is rotatably inserted into the through hole of the first axial magnetic conducting ring 14, and the outer edge end surface of the thrust portion 121 is between the two first axial magnetic conducting rings 14. The first axial magnetic conducting ring 14 is specifically inserted on the inner ring wall of the first magnetic steel ring 13 in an interference fit.

[0046] In the technical scheme, the gap between one end of the first axial magnetic conducting ring 14 facing the thrust portion 121 and the thrust portion 121 is part of the aforementioned axial air gap, which can further improve the magnetic field strength in the axial air gap, thereby further improving the axial support stiffness of the magnetic suspension bearing and improving the axial load of the magnetic suspension bearing.

[0047] Further referring to Figure 1 In some embodiments,

[0048] The inner ring wall of each radial magnetic conducting ring 111 has a second axial magnetic conducting ring 112 extending along the axial direction of the rotor 12, and the two second axial magnetic conducting rings 112 are arranged in a direction close to each other, that is, both of the two second axial magnetic conducting rings 112 extend close to the thrust portion 121 from the side away from the thrust portion 121, and the outer edge end surface of the thrust portion 121 is between the two second axial magnetic conducting rings 112, that is, the thrust portion 121 is between the two second axial magnetic conducting rings 112.

[0049] In the technical scheme, the close second axial magnetic conducting ring 112 extending towards the thrust portion 121 can reduce the thickness of the axial air gap between the radial magnetic conducting ring 111 and the thrust portion 121, ensure the conduction of the magnetic field at this position, and further ensure the reliability of the axial control.

[0050] In another preferred embodiment,

[0051] The axial control coils 15 are respectively wound on the second axial magnetic conductive rings 112, that is, the second axial magnetic conductive rings 112 serve as the winding carriers of the axial control coils 15 while serving as the magnetic conductive paths, so that the internal structure of the magnetic suspension bearing is more compact.

[0052] Further referring to Figure 1 As shown in a preferred embodiment,

[0053] Corresponding to the same end of the rotor 12, the minimum distance between the end face of the first axial magnetic conductive ring 14 and the end face of the thrust portion 121 is less than the minimum distance between the end face of the first magnetic steel ring 13 and the end face of the thrust portion 121, and further, the length of the first magnetic steel ring 13 arranged at each end of the rotor 2 is shorter than the length of the first axial magnetic conductive ring 14 and the second axial magnetic conductive ring 112.

[0054] In the technical solution, the distance between the first magnetic steel ring 13 and the thrust portion 121 is greater than the distance between the first axial magnetic conductive ring 14 and the second axial magnetic conductive ring 112 and the thrust portion 121, that is, the first magnetic steel ring 13 is designed to be concave, so that the first magnetic steel ring 13 is protected from being damaged by directly impacting the first magnetic steel ring 13 when the thrust portion 121 axially moves too much.

[0055] In a preferred embodiment, the five-freedom magnetic suspension bearing further comprises:

[0056] The second magnetic steel ring 18 is concentrically assembled on the inner wall of the magnetic conductive sleeve 11, and the specific manufacturing material thereof can be the same as or different from that of the first magnetic steel ring 13, for example, a permanent magnet, and specifically, the second magnetic steel ring 18 is assembled on the inner wall of the magnetic conductive sleeve 11 in an interference fit;

[0057] The stator core 16 is concentrically assembled on the inner ring wall of the second magnetic steel ring 18, and specifically, the stator core 16 can also be assembled on the inner ring wall of the second magnetic steel ring 18 in an interference fit. The stator core 16 has a stator yoke ring 161 and a plurality of stator teeth 162 uniformly and spaced apart along the circumference of the stator yoke ring 161. The stator core 16 has two groups, and the two groups of stator cores 16 are spaced apart along the axial direction of the rotor 12. The axial spacing between the two groups of stator cores 16 can be reasonably selected according to the design length of the rotor 2. In principle, a single group of the five-freedom magnetic suspension bearing of the present application can be used to reliably support the rotor 2 and adjust the position in the radial and axial directions.

[0058] The radial control winding 17 is respectively wound on each stator tooth 162.

[0059] In the technical solution, the two groups of stator cores 16 arranged axially and spaced apart are all arranged on the inner ring wall of the second magnetic steel ring 18, the second magnetic steel ring 18 can simultaneously provide an axial bias magnetic circuit and a radial bias magnetic circuit, that is, the five-degree-of-freedom magnetic suspension bearing of the application adopts one second magnetic steel ring 18 to simultaneously provide an axial bias magnetic circuit and a radial bias magnetic circuit, which reduces the occupation of the axial space of the internal space of the magnetic suspension bearing, reduces the axial length limit of the magnetic suspension bearing, and further helps to improve the stiffness and anti-deformation capability of the rotor 2, improves the fixed frequency of the rotor 2, and the allowable speed of the rotor 2 can be designed to be higher.

[0060] It should be noted that in the technical solution, the stator core 16 can also be referred to as a radial core, and the two stator cores 16 are integrated in one magnetic suspension bearing, effectively reducing the number of parts and material cost in the five-degree-of-freedom suspension system, and improving the market competitiveness of the product.

[0061] Specifically referring to Figure 2 As shown in the figure, the flow direction of each magnetic field in the magnetic suspension bearing of the application is shown, and as can be seen from the figure, two groups of axial bias magnetic fields are formed at the positions of the two ends of the thrust part 121, and because the first magnetic steel ring 13 of the application is added at this position, the axial bias magnetic circuit generated by the first magnetic steel ring 13 and the axial bias magnetic field strength generated by the second magnetic steel ring 18 form superposition, so that the axial magnetic field strength at the two positions is significantly improved, thereby realizing the axial support stiffness of the magnetic suspension bearing of the application, and further improving the axial load of the magnetic suspension bearing; as Figure 2 As shown in the figure, the second magnetic steel ring 18 also simultaneously provides a radial bias magnetic field.

[0062] In some embodiments,

[0063] Figure 4 The axial projection of the magnetic suspension bearing in the application is shown in the figure, and as can be seen from the figure, each group of stator cores 16 has four stator teeth 162, and in the axial projection of the rotor 12, the two stator teeth 162 symmetrically arranged about the center of the stator core 16 are serially connected with the radial control winding 17 arranged thereon, the two horizontal and vertical dashed lines in the figure divide the axial projection of the stator core 16 into four different quadrants, and each radial control winding 17 is arranged in each quadrant, and because the two groups of radial control windings 17 are in series, specifically, Figure 4The X+ coil and X- coil are connected in series to form an X coil group, while the Y+ coil and Y- coil are connected in series to form a Y coil group. When it is necessary to adjust the radial position of rotor 2, only the corresponding current needs to be supplied to the X coil group and the Y coil group, which greatly simplifies the circuit control. It is understandable that when current is supplied to the X coil group, assuming the current flow direction in the X+ coil is counterclockwise, the current flow direction in the X- coil is also clockwise. This ensures that the magnetic poles formed at the two symmetrical stator teeth 162 have the same polarity, ensuring the consistency of the radial force direction on rotor 2. Similarly, when current is supplied to the Y coil group, assuming the current flow direction in the Y+ coil is counterclockwise, the current flow direction in the Y- coil is also clockwise. This ensures that the magnetic poles formed at the two symmetrical stator teeth 162 have the same polarity, ensuring the consistency of the radial force direction on rotor 2. The specific control strategy for the current flow direction and magnitude can follow the existing control strategy for radial magnetic bearings.

[0064] In a preferred embodiment,

[0065] Each set of stator cores 16 has four stator teeth 162 that are aligned one by one in the axial direction of the rotor 12. That is, each stator tooth 162 has a corresponding relationship with each other in the axial direction, which can ensure the consistency of the radial force output direction of each stator tooth 162 and ensure reliable adjustment of the radial position of the rotor 2.

[0066] In some implementations...

[0067] Both the first magnetic ring 13 and the second magnetic ring 18 are radially magnetized, such as Figure 3 As shown in the figure, the outer radial side of each magnet ring is the S pole and the inner radial side is the N pole. In another feasible embodiment, the outer radial side of each magnet ring is the N pole and the inner radial side is the S pole. It should be understood that the inner radial poles of the two magnet rings should be the same and the outer radial poles should also be the same.

[0068] According to the embodiment of the present application, a motor is also provided, which comprises the five-degree-of-freedom magnetic suspension bearing. Due to the adoption of the five-degree-of-freedom magnetic suspension bearing, the first magnetic steel ring 13 is arranged at each end surface position of the thrust portion 121 of the rotor 12, and the first magnetic steel ring 13 can improve the magnetic field intensity in the axial air gap between the radial magnetic guide ring 111 and the thrust portion 121, thereby improving the axial support stiffness of the magnetic suspension bearing, and further improving the axial load of the magnetic suspension bearing. In a specific embodiment, the motor comprises a motor rotor assembly and a motor stator assembly, wherein the motor rotor assembly comprises a rotor core and a rotor magnetic steel assembled on the rotor core, and the rotor core is sleeved on the shaft end segment of the rotor 2 extending out of the magnetic guide sleeve 11. Since the five-degree-of-freedom magnetic suspension bearing of the present application has two stator cores 16 arranged in the axial direction of the rotor 2, reliable suspension support can be formed for the motor rotor assembly.

[0069] It is easy for those skilled in the art to understand that the advantageous technical features of each mode described above can be freely combined and superimposed without conflict.

[0070] The above is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above is only the preferred embodiment 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 variations can be made, and these improvements and variations should be considered as the protection scope of the present application.

Claims

1. A five-degree-of-freedom magnetic levitation bearing, characterized in that, include: A magnetic sleeve (11) has a radial magnetic ring (111) extending inward along the radial direction of the magnetic sleeve (11) at each of its axial ends. Each radial magnetic ring (111) has a first magnetic steel ring (13) arranged concentrically on its inner ring wall. The rotor (12) includes a thrust portion (121) and shaft end sections (122) located on both axial sides of the thrust portion (121). Each shaft end section (122) is inserted into a through hole of a first magnetic ring (13). A first axial guide magnetic ring (14) is also installed in the through hole of each first magnetic ring (13). Each shaft end section (122) is rotatably inserted into the through hole of the first axial guide magnetic ring (14), and the outer edge end face of the thrust portion (121) is located between two first axial guide magnetic rings (14). Each radial guide magnetic ring (111) has... The inner ring wall has a second axial guide magnetic ring (112) extending along the axial direction of the rotor (12), and the two second axial guide magnetic rings (112) are arranged to protrude in a direction close to each other. The outer edge end face of the thrust portion (121) is located between the two second axial guide magnetic rings (112). Corresponding to the same end of the rotor (12), the minimum distance between the end face of the first axial guide magnetic ring (14) and the second axial guide magnetic ring (112) and the end face of the thrust portion (121) is less than the minimum distance between the end face of the first magnetic ring (13) and the end face of the thrust portion (121).

2. The five-degree-of-freedom magnetic levitation bearing according to claim 1, characterized in that, Each axial control coil (15) is wound on each of the second axial guide magnetic rings (112).

3. The five-degree-of-freedom magnetic levitation bearing according to claim 1, characterized in that, Also includes: The second magnetic ring (18) is concentrically assembled on the inner wall of the magnetic sleeve (11); The stator core (16) is concentrically assembled on the inner ring wall of the second magnetic steel ring (18), and has a stator yoke ring (161) and a plurality of stator teeth (162) evenly spaced along the circumference of the stator yoke ring (161). The stator core (16) has two sets, and the two sets of stator cores (16) are spaced apart along the axial direction of the rotor (12). Radial control windings (17) are wound on each of the stator teeth (162).

4. The five-degree-of-freedom magnetic levitation bearing according to claim 3, characterized in that, Each group of stator cores (16) has four stator teeth (162). On the axial projection of the rotor (12), the radial control windings (17) wound on two stator teeth (162) symmetrical about the center of the stator core (16) are connected in series.

5. The five-degree-of-freedom magnetic levitation bearing according to claim 4, characterized in that, The four stator teeth (162) of each group of stator cores (16) are aligned one by one in the axial direction of the rotor (12).

6. The five-degree-of-freedom magnetic levitation bearing according to claim 3, characterized in that, Both the first magnetic ring (13) and the second magnetic ring (18) are radially magnetized.

7. An electric motor, characterized in that, The five-degree-of-freedom magnetic levitation bearing includes any one of claims 1 to 6.

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