Magnetic suspension active three-degree-of-freedom bearings, compressors, motors

Abstract

The present invention provides a magnetic suspension active three-degree-of-freedom bearing, a compressor, and a motor, wherein the magnetic suspension active three-degree-of-freedom bearing includes a bearing rotor, a radial stator assembly, etc. The radial stator assembly includes a radial stator, and the radial stator has 16 poles, which are centrally symmetrical about the center of the rotating shaft and distributed in 4 quadrants, each quadrant has a middle pole and two side poles on both sides thereof, the two middle poles and the two side poles are symmetrical about the angular bisector of the corresponding quadrant, and in the same quadrant, the polarities formed by the adjacent side poles and the middle poles are opposite, and the axial stator assembly has an axial coil arranged on a circular rotating shaft. The present invention does not need to assemble a thrust plate separately on the rotating shaft, the structure is more compact, the process is simplified, the bearing volume is effectively reduced, the rotating shaft length is shortened, the critical speed of the rotor is increased, and the operating stability of the magnetic suspension system is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic suspension bearings, and in particular relates to a magnetic suspension active three-degree-of-freedom bearing, a compressor, and a motor. Background Art

[0002] Magnetic bearings (abbreviated as magnetic bearings) use the electromagnetic force on the rotor to suspend the rotating shaft, and the rotating shaft and stator remain in a non-contact state, so they have the advantages of no wear, high speed, high precision, and long life. Magnetic bearings can be divided into three categories according to their working principles: active magnetic bearings, passive magnetic bearings, and hybrid magnetic bearings. Magnetic bearings are further divided into radial magnetic bearings and axial magnetic bearings. The radial magnetic bearings adjust the radial position of the rotating shaft through the electromagnetic force between the radial rotor and the radial rotor, and the axial magnetic bearings adjust the axial position of the rotating shaft through the electromagnetic force between the thrust plate on the rotating shaft. In a magnetic suspension system, radial magnetic bearings and axial magnetic bearings are configured at both ends of the rotating shaft, thereby adjusting the three-degree-of-freedom direction position of the rotating shaft. However, the radial magnetic bearing and the axial magnetic bearing that are independently arranged have a low degree of integration and occupy the size of the rotating shaft, thereby causing the rotating shaft length to be relatively large, which is not conducive to the improvement of the critical speed of the rotor. Of course, in some existing technologies, there are also three-degree-of-freedom magnetic bearings that integrate the radial magnetic bearing and the axial magnetic bearing into a whole. However, the structural design of the radial bearing and the axial bearing in this three-degree-of-freedom magnetic bearing is not reasonable enough, resulting in the magnetic lines of force of the radial bearing and the magnetic lines of force of the axial bearing each forming a passage through the corresponding rotor parts such as the radial rotor or the thrust plate. The overall structure is complex, the processing and manufacturing process is complex, the assembly is difficult, and the degree of integration is relatively low. Summary of the invention

[0003] Therefore, the present invention provides a magnetically suspended active three-degree-of-freedom bearing, a compressor, and a motor, which can solve the technical problems that the structural design of the radial bearing and the axial bearing in the three-degree-of-freedom magnetic bearing in the prior art is not reasonable, resulting in the magnetic lines of force of the radial bearing and the magnetic lines of force of the axial bearing each forming a passage through the corresponding rotor parts, the overall structure is complex, the processing and manufacturing process is complex, the assembly is difficult, and the degree of integration is low.

[0004] In order to solve the above problems, the present invention provides a magnetically suspended active three-degree-of-freedom bearing, comprising a bearing rotor for fixed sleeve connection with a rotating shaft, a radial stator assembly sleeved on the radial outer side of the bearing rotor, and a first axial stator assembly and a second axial stator assembly at both axial ends of the bearing rotor, wherein the first axial stator assembly and the second axial stator assembly respectively form an axial magnetic circuit with the bearing rotor and the radial stator assembly to adjust the axial position of the bearing rotor, and a radial magnetic circuit is formed between the radial stator assembly and the bearing rotor to adjust the radial position of the bearing rotor, and the radial stator assembly The component comprises a radial stator, wherein the radial stator has 16 poles extending toward one side of the bearing rotor. In the axial projection of the rotating shaft, the 16 poles are centrally symmetrical about the center of the rotating shaft and are distributed in 4 quadrants. Each of the quadrants has a middle pole and two side poles on both sides of the middle pole. The two middle poles and the two side poles are symmetrical about the angular bisector of the corresponding quadrant, and in the same quadrant, the polarities formed by the adjacent side poles and the middle poles are opposite. The first axial stator component and the second axial stator component both have axial coils arranged around the rotating shaft.

[0005] In some embodiments, the circumferential width of the middle pole is greater than the circumferential width of the side pole.

[0006] In some embodiments, the circumferential width of the middle pole is twice the circumferential width of the side poles.

[0007] In some embodiments, a radial coil is wound around each pole, the radial coils wound around two side poles are connected in series, and the radial coils wound around two middle poles are connected in series.

[0008] In some embodiments, the first axial stator assembly includes a first axial stator, the first axial stator having a first inner magnetic ring and a first outer magnetic ring, the axial coil is located between the first inner magnetic ring and the first outer magnetic ring, wherein a first axial inner working gap is formed between the first inner magnetic ring and the left end surface of the bearing rotor, a first axial outer working gap is formed between the first outer magnetic ring and the left end surface of the radial stator, and the first outer magnetic ring is located radially inside the radial coil.

[0009] In some embodiments, the second axial stator assembly includes a second axial stator, the second axial stator having a second inner magnetic ring and a second outer magnetic ring, the axial coil is located between the second inner magnetic ring and the second outer magnetic ring, wherein a second axial inner working gap is formed between the second inner magnetic ring and the right end surface of the bearing rotor, a second axial outer working gap is formed between the second outer magnetic ring and the right end surface of the radial stator, and the second outer magnetic ring is located radially inside the radial coil.

[0010] In some embodiments, the control of the radial coils wound on the middle poles in each quadrant is independent of the control of the radial coils wound on the side poles.

[0011] In some embodiments, the current flowing through the axial coils in the first axial stator assembly is opposite to the current flowing through the axial coils in the second axial stator assembly.

[0012] The present invention also provides a compressor, comprising the above-mentioned magnetic suspension active three-degree-of-freedom bearing.

[0013] The present invention also provides a motor, comprising the above-mentioned magnetic suspension active three-degree-of-freedom bearing.

[0014] The present invention provides a magnetic levitation active three-degree-of-freedom bearing, compressor, and motor. No thrust plate needs to be separately assembled on the rotating shaft, and the overall structure and processing technology are simplified, which is convenient for assembly. The degree of integration is high, the structure is more compact, and the volume of the bearing is effectively reduced, the length of the rotating shaft is shortened, the critical speed of the rotor is increased, and the operating stability of the magnetic levitation system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the internal structure of a magnetically suspended active three-degree-of-freedom bearing according to an embodiment of the present invention, wherein the dotted arrows in the figure indicate the flow direction of the axial magnetic circuit;

[0016] Figure 2 for Figure 1 The relative position relationship between the radial stator and the bearing rotor in the figure. The dotted arrows in the figure show the flow direction of the axial magnetic circuit, and the solid arrows in the figure show the flow direction of the radial magnetic circuit.

[0017] The reference numerals are:

[0018] 1. Bearing rotor; 10. Rotating shaft; 21. Radial stator; 211. Middle pole; 212. Side pole; 214. Stator yoke; 31. First axial stator; 311. First inner magnetic ring; 312. First outer magnetic ring; 41. Second axial stator; 411. Second inner magnetic ring; 412. Second outer magnetic ring; 51. Axial coil; 52. Radial coil; 001. Axial magnetic circuit; 002. Radial magnetic circuit; 003. Radial working gap; 004. First axial inner working gap; 005. Second axial inner working gap. DETAILED DESCRIPTION

[0019] See also Figure 1 to Figure 2As shown, a magnetic suspension active three-degree-of-freedom bearing is provided, including a bearing rotor 1 for fixedly sleeved with a rotating shaft 10, a radial stator assembly sleeved on the radial outer side of the bearing rotor 1, and a first axial stator assembly and a second axial stator assembly respectively located at two axial ends of the bearing rotor 1, the first axial stator assembly and the second axial stator assembly respectively form an axial magnetic circuit 001 with the bearing rotor 1 and the radial stator assembly to adjust the axial position of the bearing rotor 1, and a radial magnetic circuit 002 is formed between the radial stator assembly and the bearing rotor 1 to adjust the radial position of the bearing rotor 1, the radial stator assembly includes a radial stator 21, and the radial stator 21 includes a stator yoke 214, and the inner ring of the stator yoke 214 has 16 poles extending toward one side of the bearing rotor 1, and in the axial projection of the rotating shaft 10, the 16 poles are centrally symmetrical about the center of the rotating shaft 10 and are distributed in 4 quadrants, and the 3 poles in each quadrant have an intermediate pole 211 and Two side poles (212) are located on both sides of the middle pole 211, the two middle poles (211) and the two side poles (212) are symmetrical about the angular bisector of the corresponding quadrant, and in the same quadrant, the polarities formed by adjacent side poles (212) and the middle pole (211) are opposite, one side pole 212, two middle poles 211 and another side pole 212 form a └┴┴┘-shaped structure, and the first axial stator component and the second axial stator assembly both have an axial coil (51) arranged around the rotating shaft (10), that is, the axial coil 51 is arranged around the rotating shaft 10 (also called a single coil mode). It can be understood that the aforementioned four quadrants specifically refer to the center of the rotating shaft 10 as the coordinate origin O, and an orthogonal coordinate system XOY is established through the O point. The orthogonal coordinate system XOY divides the aforementioned axial projection into four adjacent quadrants. This aspect is basic geometric knowledge and will not be elaborated. In this technical solution, the bearing rotor is simultaneously used as a conducting component of the axial magnetic circuit 001 and the radial magnetic circuit 002, and the thrust plate and the bearing rotor in the prior art are integrated into one. The integration degree of the bearing is further improved. There is no need to assemble the thrust plate separately on the rotating shaft 10, and the bearing rotor is a magnetic circuit shared by the radial stator assembly and the axial stator assembly. The overall structure and processing technology are simplified, easy to assemble, with a high degree of integration and a more compact structure. The bearing volume is effectively reduced, the shaft length is shortened, the rotor critical speed is increased, and the operation stability of the magnetic suspension system is improved.

[0020] Specific combination Figure 2As shown, the aforementioned four quadrants are respectively the first quadrant on the upper right, the second quadrant on the upper left, the third quadrant on the lower left, and the fourth quadrant on the lower right. Taking the three poles in the first quadrant as an example, the energizing direction of each radial coil 52 shown in the figure is used as the standard, wherein the free ends of the middle pole 211 present an S pole (upper left) and the other present an N pole (lower right), the free end of one side pole 212 presents an N pole, and the other side pole 212 presents an S pole. In the side pole 212 on the upper left and the middle pole 211 on the lower right, the flow direction of the radial magnetic circuit 002 is the same as the flow direction of the axial magnetic circuit 001, so that the two poles can be increased respectively with the bearing rotation. The magnetic flux between the poles 211 and the bearing rotor 1 is weakened, thereby increasing the radial force at these two places. In the middle pole 211 on the upper left and the side pole 212 on the lower right, the flow directions of the radial magnetic circuit 002 and the axial magnetic circuit 001 are opposite. This weakens the magnetic flux between the two poles and the bearing rotor 1, thereby reducing the radial force at these places. The aforementioned content is aimed at the influence of the axial magnetic flux on the poles in one quadrant, and the enhancement and weakening of the radial magnetic flux in the four quadrants offset each other. Although the radial magnetic circuit and the axial magnetic circuit of the integrated magnetic bearing both flow through the bearing rotor 1, the change of the axial magnetic circuit will not affect the radial magnetic circuit as a whole, thereby simplifying the control of the magnetic bearing.

[0021] In some embodiments, the circumferential width of the middle pole 211 is greater than the circumferential width of the side pole 212. Figure 2 As shown, the middle pole 211 also serves as a flow component for the magnetic lines of force in the side poles 212. The circumferential width of the middle pole 211 is designed to be larger than the circumferential width of the two adjacent poles, so that the magnetic circuits on both sides can be optimized. In a preferred embodiment, the circumferential width of the middle pole 211 is twice the circumferential width of the side poles 212. In this way, the magnetic pole area of ​​the middle pole 211 is twice that of the two end poles, that is, the side poles 212. At the same time, the middle pole 211 and the side poles 212 are connected in series to ensure that the radial control turns and the radial current are consistent, so that only one current needs to be adjusted to control the radial movement. This control method is simple, ensuring that the radial magnetic flux of the middle pole 211 is twice that of the two ends, the radial magnetic flux density on the four poles is consistent and the magnetic circuit is not easy to saturate. At the same time, the influence of the middle axial magnetic circuit can also be taken into account, and the axial magnetic flux density on the four poles is consistent and the magnetic circuit is not easy to saturate.

[0022] Each pole is wound with a radial coil 52. The radial coils 52 wound with the two side poles 212 are connected in series, and the radial coils 52 wound with the two middle poles 211 are connected in series. Figure 2As shown, in the first quadrant, the current flow direction of the radial coil 52 corresponding to the upper left side pole 212 and the lower right middle pole 211 is left-in and right-out, while the current flow direction of the radial coil 52 corresponding to the upper left middle pole 211 and the lower right side pole 212 is right-in and left-out, thereby achieving that the magnetic poles of the four poles in the first quadrant are NSNS in the clockwise direction. Of course, the current flow direction can be exactly opposite so that the magnetic poles of the four poles in the first quadrant are SNSN in the clockwise direction. It should be noted that the polarity of the poles in other quadrants should meet the requirement of symmetry about the center of the rotating shaft 10. In this technical solution, by connecting the radial coils 52 of the two side poles 212 in series and the radial coils 52 of the two middle poles 211 in series, the magnetic forces presented by the two poles are completely consistent, which is convenient for adjusting and controlling the radial position.

[0023] In some embodiments, the first axial stator assembly includes a first axial stator 31, the first axial stator 31 has a first inner magnetic ring 311 and a first outer magnetic ring 312, the axial coil 51 is located between the first inner magnetic ring 311 and the first outer magnetic ring 312, wherein a first axial inner working gap 004 is formed between the first inner magnetic ring 311 and the left end face of the bearing rotor 1, a first axial outer working gap is formed between the first outer magnetic ring 312 and the left end face of the radial stator 21, and the first outer magnetic ring 312 is located radially inside the radial coil 52. Similarly, the second axial stator assembly includes a second axial stator 41, which has a second inner magnetic ring 411 and a second outer magnetic ring 412, and the axial coil 51 is located between the second inner magnetic ring 411 and the second outer magnetic ring 412, wherein a second axial inner working gap 005 is formed between the second inner magnetic ring 411 and the right end face of the bearing rotor 1, a second axial outer working gap is formed between the second outer magnetic ring 412 and the right end face of the radial stator 21, and the second outer magnetic ring 412 is located radially inside the radial coil 52. In this technical solution, the first outer magnetic ring 312 or the second outer magnetic ring 412 is arranged corresponding to the pole position of the radial stator 21 and is located inside the radial coil 52, but is not arranged corresponding to the stator yoke 214 of the radial stator 21, which can reduce the leakage magnetic flux of the radial magnetic circuit 002 in the axial direction and prevent the occurrence of circumferential unevenness of the axial output.

[0024] In some embodiments, the control of the radial coil 52 wound on the middle pole 211 in each quadrant is independent of the control of the radial coil 52 wound on the side pole 212. Figure 2 As shown, the radial stator assembly has 16 magnetic poles (specifically the aforementioned poles), which are symmetrically distributed in four The two ends of the structure are small teeth (that is, the side poles 212 mentioned above, the same below), and the middle is a large tooth (that is, the middle pole 211 mentioned above, the same below). The magnetic poles of the shaped structure are distributed in NSNS (or SNSN) in space, and the radial magnetic circuit 002 is as follows Figure 2 As shown by the solid line, The first radial magnetic circuit on the axial structure passes through radial small tooth a (for example, the upper left side pole 212 in the first quadrant, the same below) - radial working gap 003 - bearing rotor 1 - radial working gap 003 - radial large tooth b (for example, the upper left middle pole 211 in the first quadrant, the same below) - stator yoke 214 to radial small tooth a and is closed; the second radial magnetic circuit passes through radial large tooth c (for example, the lower right middle pole 211 in the first quadrant, the same below) - radial working gap 003 - bearing rotor 1 - radial working gap 003 - radial large tooth b - stator yoke 214 to radial large tooth c and is closed; the third radial magnetic circuit passes through radial large tooth c - radial working gap 003 - bearing rotor 1 - radial working gap 003 - radial small tooth d (for example, the lower right side pole 212 in the first quadrant, the same below) - stator yoke 214 to radial large tooth c and is closed. The axial magnetic circuit 001 is as shown in FIG. Figure 2 As shown by the dotted lines, all point to the center of the circle. The air gap magnetic field of the radial small tooth a and radial large tooth c of the shaped structure is enhanced, and the air gap magnetic field of the radial large tooth b and radial small tooth d is weakened. On the contrary, when the axial magnetic circuit direction is all pointing to the circumference, The air gap magnetic field of the radial large tooth b and radial small tooth d of the shaped structure is enhanced, while the air gap magnetic field of the radial small tooth a and radial large tooth c is weakened. When the bearing rotor needs to be controlled to move to the upper left, the upper left radial winding is energized to provide the bearing rotor with a radial force to the upper left; when the bearing rotor needs to be controlled to move upward, the upper left and right radial windings are energized to provide the bearing rotor with an upward radial force. This control has a wide range of radial movement directions and flexible control.

[0025] In some embodiments, the current flowing through the axial coil 51 in the first axial stator assembly is opposite to the current flowing through the axial coil 51 in the second axial stator assembly to ensure that the radial magnetic circuit 001 generated by the axial stator assemblies at both ends simultaneously enhances or weakens the radial magnetic circuit 002, thereby facilitating the control of the bearing rotor 1 to adjust the axial position of the bearing rotor 1.

[0026] Axial magnetic circuit 001 can be found in detail Figure 1 As shown, the outer magnetic ring of the axial stator is located at the lower end of the radial coil 52 ( Figure 1The inner magnetic ring of the axial stator is located at both ends of the bearing rotor 1. The axial magnetic circuit 001 generated by the axial coil 51 includes a first axial magnetic circuit and a second axial magnetic circuit, which are used to control the axial movement of the bearing rotor. The first axial magnetic circuit passes through the first outer magnetic ring 312-pole-radial working gap 003-bearing rotor 1-first axial inner working gap 004-first inner magnetic ring 311 back to the first axial stator 31 and closes in the clockwise direction. The second axial magnetic circuit passes through the second outer magnetic ring 412-pole-radial working gap 003-bearing rotor 1-first axial inner working gap 004-first inner magnetic ring 311 back to the first axial stator 31 and closes in the clockwise direction. 03-bearing rotor 1-second axial inner working gap 005-the second inner magnetic ring 411 returns to the second axial stator 41 and closes counterclockwise. When the bearing rotor 1 needs to be controlled to move to the left, the current of the left bearing winding (that is, the left axial coil 51) is increased, and the bearing rotor 1 is subjected to a large force to the left. Conversely, when the bearing rotor 1 needs to be controlled to move to the right, the current of the right bearing winding (that is, the right axial coil 51) is increased, and the bearing rotor 1 is subjected to a large force to the right. Therefore, the axial movement of the bearing rotor 1 is controlled by controlling the current of the left second axial winding.

[0027] It should be particularly noted that the bearing of the present invention is an active electromagnetic bearing and does not have a permanent magnet to provide a bias magnetic field, so that the bearing of the present invention has the advantages of low cost, easy assembly, large bearing capacity, and high-power operation.

[0028] According to an embodiment of the present invention, there is further provided a compressor, comprising the above-mentioned magnetically suspended active three-degree-of-freedom bearing.

[0029] According to an embodiment of the present invention, there is further provided a motor, comprising the above-mentioned magnetically suspended active three-degree-of-freedom bearing.

[0030] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0031] 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 magnetically suspended active three-degree-of-freedom bearing, characterized in that: The invention comprises a bearing rotor (1) for fixedly sleeved with a rotating shaft (10), a radial stator assembly sleeved on the radial outer side of the bearing rotor (1), and a first axial stator assembly and a second axial stator assembly respectively located at two axial ends of the bearing rotor (1), wherein the first axial stator assembly and the second axial stator assembly respectively form an axial magnetic circuit (001) with the bearing rotor (1) and the radial stator assembly to adjust the axial position of the bearing rotor (1), and a radial magnetic circuit (002) is formed between the radial stator assembly and the bearing rotor (1) to adjust the radial position of the bearing rotor (1), and the radial stator assembly comprises a radial stator (21), wherein the radial stator (21) has 16 poles extending toward one side of the bearing rotor (1), and in the axial projection of the rotating shaft (10), the 16 poles are centrally symmetrical about the center of the rotating shaft (10) and distributed in four quadrants, and each quadrant has two middle poles (211) and a middle pole ( The two side poles (212) are arranged on both sides of the first axial stator assembly (10), the two middle poles (211) and the two side poles (212) are all symmetrical about the angular bisector of the corresponding quadrant, and in the same quadrant, the polarities formed by the adjacent side poles (212) and the middle poles (211) are opposite, the first axial stator assembly and the second axial stator assembly both have axial coils (51) arranged around the rotating shaft (10), and the currents of the two axial coils (51) are in opposite directions; each A radial coil (52) is wound around each of the poles; the first axial stator assembly comprises a first axial stator (31), the first axial stator (31) has a first outer magnetic ring (312), and the first outer magnetic ring (312) is located radially inside the radial coil (52); the second axial stator assembly comprises a second axial stator (41), the second axial stator (41) has a second outer magnetic ring (412), and the second outer magnetic ring (412) is located radially inside the radial coil (52).

2. The magnetically suspended active three-degree-of-freedom bearing according to claim 1, characterized in that: The circumferential width of the middle pole (211) is greater than the circumferential width of the side pole (212).

3. The magnetically suspended active three-degree-of-freedom bearing according to claim 2, characterized in that: The circumferential width of the middle pole (211) is twice the circumferential width of the side pole (212).

4. The magnetically suspended active three-degree-of-freedom bearing according to any one of claims 1 to 3, characterized in that: The radial coils (52) wound around the two side poles (212) are connected in series, and the radial coils (52) wound around the two middle poles (211) are connected in series.

5. The magnetically suspended active three-degree-of-freedom bearing according to claim 4, characterized in that: The first axial stator (31) also has a first inner magnetic ring (311), and the axial coil (51) is located between the first inner magnetic ring (311) and the first outer magnetic ring (312), wherein a first axial inner working gap (004) is formed between the first inner magnetic ring (311) and the left end face of the bearing rotor (1), and a first axial outer working gap is formed between the first outer magnetic ring (312) and the left end face of the radial stator (21).

6. The magnetically suspended active three-degree-of-freedom bearing according to claim 4, characterized in that: The second axial stator (41) also has a second inner magnetic ring (411), and the axial coil (51) is located between the second inner magnetic ring (411) and the second outer magnetic ring (412), wherein a second axial inner working gap (005) is formed between the second inner magnetic ring (411) and the right end face of the bearing rotor (1), and a second axial outer working gap is formed between the second outer magnetic ring (412) and the right end face of the radial stator (21).

7. The magnetically suspended active three-degree-of-freedom bearing according to claim 4, characterized in that: The control of the radial coil (52) wound on the middle pole (211) in each quadrant is independent of the control of the radial coil (52) wound on the side pole (212).

8. A compressor, characterized in that: A magnetically suspended active three-degree-of-freedom bearing comprising any one of claims 1 to 7.

9. A motor, characterized in that: A magnetically suspended active three-degree-of-freedom bearing comprising any one of claims 1 to 7.

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