An asymmetric axial magnetic bearing

Abstract

The application relates to an asymmetric axial magnetic suspension bearing, which comprises a rotating shaft connected with a thrust disc, an upper thrust disc stator and a lower thrust disc stator connected with a motor shell respectively, and the end faces of the upper thrust disc stator and the lower thrust disc stator opposite to the thrust disc are provided with a certain distance respectively; the outer diameter of an upper thrust disc stator cover plate matches the outer diameter of the upper thrust disc stator; the upper thrust disc stator cover plate is arranged on the upper thrust disc stator so that a first wire package is fixed in the upper thrust disc stator; the end face of the upper thrust disc stator cover plate is flush with the inner ring end face of the upper thrust disc stator; the outer diameter of a lower thrust disc stator cover plate matches the outer diameter of the lower thrust disc stator; the lower thrust disc stator cover plate is arranged on the lower thrust disc stator so that a second wire package is fixed in the lower thrust disc stator groove; the lower end face of the lower thrust disc stator cover plate is flush with the lower end face of the thrust disc, and the distance between the lower thrust disc stator cover plate and the upper thrust disc stator cover plate is greater than the gap between the lower thrust disc stator cover plate and the thrust disc.

Description

TECHNICAL FIELD

[0001] The present application relates to magnetic bearing technology, in particular to an asymmetric axial magnetic suspension bearing. BACKGROUND

[0002] The existing motor uses mechanical bearing support, which is restricted by mechanical bearing friction and rotor vibration, and the motor can only run at low speed, with small power density and low efficiency. At the same time, the mechanical bearing has high energy consumption, poor reliability, serious noise pollution and oil pollution.

[0003] The high-speed motor supported by the magnetic bearing eliminates friction and wear, and since the magnetic bearing does not need lubrication, the speed of the high-speed motor can be as high as tens of thousands of revolutions per minute, with the advantages of large power density, high energy efficiency, small volume, light weight, fast response, etc. It is an ideal supporting component for the development of future high-speed rotating power machinery. The existing axial magnetic bearing scheme is mostly a single-sided force structure of a thrust disc or a double-sided symmetric force structure of a thrust disc.

[0004] Figure 1 As shown in a single-sided force structure of a thrust disc of an existing axial magnetic bearing, as shown in the figure, Figure 1 The single-sided force structure of the thrust disc is only subjected to the action of electromagnetic force, which overcomes the gravity and axial aerodynamic force of the rotor to make the rotor suspended, and the required electromagnetic force is large, the number of turns of the coil is large, causing energy waste; At the same time, only the single-sided thrust disc stator can be controlled and adjusted, which is not conducive to stable operation of the rotor.

[0005] Figure 2 As shown in a double-sided symmetric force structure of a thrust disc of an existing axial magnetic bearing, as shown in the figure, Figure 2 The double-sided force structure of the thrust disc can adjust the current of the upper and lower stators of the thrust disc through the feedback signal of the sensor at any time to make the rotor run stably, but a large bias current is still needed to overcome the gravity and axial aerodynamic force of the rotor to make the rotor suspended, causing energy waste, and the sensor is placed above the rotating shaft 1, occupying the overall space. SUMMARY

[0006] The purpose of the present application is to provide an asymmetric axial magnetic suspension bearing to solve the problems in the prior art.

[0007] The present invention discloses an asymmetric axial magnetic suspension bearing, which comprises: a rotating shaft, a thrust plate, an upper thrust plate stator, a first coil, a second coil, an upper thrust plate stator cover, a lower thrust plate stator, and a lower thrust plate stator cover; the rotating shaft is connected to the thrust plate, and the upper thrust plate stator and the lower thrust plate stator are respectively connected to the motor housing; the upper thrust plate stator, the lower thrust plate stator and the end faces opposite to the thrust plate are respectively at a certain distance; the upper thrust plate stator The outer diameter of the cover plate matches the outer diameter of the upper thrust plate stator, and the inner diameter of the upper thrust plate stator cover plate is smaller than the outer diameter of the thrust plate; the upper thrust plate stator cover plate is arranged on the upper thrust plate stator, and the upper thrust plate stator cover plate is fastened to the upper thrust plate stator, so that the first coil is fixed in the space surrounded by the upper thrust plate stator and one end face of the upper thrust plate stator cover plate; the other end face of the upper thrust plate stator cover plate is flush with the inner ring end face of the upper thrust plate stator; the lower thrust plate stator The outer diameter of the cover plate matches the outer diameter of the lower thrust disc stator, and the inner diameter of the lower thrust disc stator cover plate is larger than the outer diameter of the thrust disc; the lower thrust disc stator cover plate is arranged on the lower thrust disc stator, and the lower thrust disc stator cover plate is fastened to the lower thrust disc stator, so that the second coil is fixed in the space surrounded by the lower thrust disc stator and one end face of the lower thrust disc stator cover plate, and the lower end face of the thrust disc is flush with the end face of the lower thrust disc stator cover plate, and the lower thrust disc stator cover plate is fixed to the lower thrust disc stator. The distance between the plate and the upper thrust plate stator cover is greater than the gap between the lower thrust plate stator cover and the thrust plate; when the current changes, a magnetic circuit is formed between the upper thrust plate stator, the upper thrust plate stator cover and the thrust plate, and the thrust plate is subjected to an upward magnetic pull, while a magnetic circuit is formed between the lower thrust plate stator, the lower thrust plate stator cover and the thrust plate, and the thrust plate is subjected to a downward magnetic pull; the difference in the electromagnetic pull on the thrust plate is equal to the gravity of the rotor itself.

[0008] According to an embodiment of the asymmetric axial magnetic bearing of the present invention, it also includes: a first sensor and a second sensor, the first sensor is embedded in the upper thrust plate stator, and the second sensor is embedded in the lower thrust plate stator. The first sensor and the second sensor are symmetrically arranged to detect the rotor position.

[0009] According to an embodiment of the asymmetric axial magnetic bearing of the present invention, the first sensor and the second sensor are respectively 0.5-0.6 mm away from the upper and lower end surfaces of the thrust plate.

[0010] According to an embodiment of the asymmetric axial magnetic bearing of the present invention, the rotating shaft and the thrust plate are fixed by shrink fitting or threaded connection; the upper thrust plate stator and the lower thrust plate stator are respectively fastened to the outer shell by shrink fitting or screws; the outer ring of the lower thrust plate stator cover is fastened to the lower thrust plate stator by screws, and the outer ring of the upper thrust plate stator cover is fastened to the upper thrust plate stator by screws; the upper thrust plate stator and the lower thrust plate stator are respectively 0.3 to 0.6 mm away from the end faces opposite to the thrust plate.

[0011] According to an embodiment of the asymmetric axial magnetic bearing of the present invention, the first coil and the second coil are made of copper wire, the first coil is arranged in the stator slot of the upper thrust plate, and the second coil is arranged in the stator slot of the lower thrust plate.

[0012] According to an embodiment of the asymmetric axial magnetic bearing of the present invention, the lower thrust plate stator, the upper thrust plate stator, the upper thrust plate stator cover, the lower thrust plate stator cover and the thrust plate are made of soft magnetic materials.

[0013] According to an embodiment of the asymmetric axial magnetic bearing of the present invention, when current is passed through the first coil, the path of the magnetic lines of force is the upper thrust plate stator, the upper thrust plate stator cover, enters the thrust plate, and then returns to the upper thrust plate stator, forming a loop, which generates an upward suction force on the rotor; when current is passed through the second coil, the path of the magnetic lines of force is the lower thrust plate stator, the lower thrust plate stator cover, enters the thrust plate, and then returns to the lower thrust plate stator, forming a loop, which generates a downward suction force on the rotor.

[0014] According to an embodiment of the asymmetric axial magnetic bearing of the present invention, the upper thrust plate stator cover plate, the lower thrust plate stator cover plate and the end surface area of ​​the thrust plate are matched, so that when current is passed through the first coil or the second coil, the axial upward pulling force of the thrust plate stator on the thrust plate is greater than the axial downward pulling force, so that the difference between the upper and lower pulling forces on the thrust plate is equal to the gravity of the rotor itself, achieving force balance and allowing the rotor to be suspended and operate stably.

[0015] According to an embodiment of the asymmetric axial magnetic bearing of the present invention, the distance between the upper thrust plate stator and one end surface of the thrust plate is smaller than the distance between the lower thrust plate stator and the other end surface of the thrust plate.

[0016] According to an embodiment of the asymmetric axial magnetic bearing of the present invention, the number of turns of the first wire is different from the number of turns of the second wire, so as to adjust the difference between the upper and lower pulling forces on the thrust plate.

[0017] The asymmetric axial magnetic suspension bearing of the present invention has the advantages of low loss, simple control and small space occupation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure shows a single-side force structure diagram of an existing axial magnetic bearing thrust plate;

[0019] Figure 2 The figure shows a bilaterally symmetrical force structure diagram of a thrust plate of an existing axial magnetic bearing;

[0020] Figure 3 Shown is a schematic diagram of an asymmetric axial magnetic bearing of the present invention;

[0021] Figure 4The figure shows the position relation diagram of the asymmetric axial magnetic suspension bearing of the present application.

[0022] Figure 5 The figure shows the perspective view of the single axial magnetic suspension bearing of the present application.

[0023] Figure 6 The figure shows the system explosion diagram of the asymmetric axial magnetic suspension bearing of the present application.

[0024] Figure 7 The figure shows the distance diagram of the thrust disc stator cover plate and the thrust disc end surface.

[0025] Figure 8 The figure shows the magnetic circuit diagram of the asymmetric axial magnetic suspension bearing of the present application.

[0026] Figure 9 The figure shows the axial force diagram of the thrust disc.

[0027] Figure 10 The figure shows the distance diagram of the upper thrust disc stator and the lower thrust disc stator and the thrust disc end surface.

[0028] Figure 11 The figure shows the first and second wire winding number diagram. DETAILED DESCRIPTION

[0029] In order to make the purpose, content and advantages of the present application more clear, the specific embodiment of the present application is described in further detail below in combination with the drawings and examples.

[0030] Figure 3 The figure shows the schematic diagram of the asymmetric axial magnetic suspension bearing of the present application, Figure 4 The figure shows the position relation diagram of the asymmetric axial magnetic suspension bearing of the present application, Figure 5 The figure shows the perspective view of the single axial magnetic suspension bearing of the present application, Figure 6 The figure shows the system explosion diagram of the asymmetric axial magnetic suspension bearing of the present application, such as Figures 3 to 6 As shown in the figure, the asymmetric axial magnetic suspension bearing of the present application comprises a rotating shaft 1, a thrust disc 2, an upper thrust disc stator 3, a first wire winding 4, a second wire winding 8, an upper thrust disc stator cover plate 5, a lower thrust disc stator 7, a lower thrust disc stator cover plate 9, a first sensor 6 and a second sensor 10.

[0031] As shown in the figure, the asymmetric axial magnetic suspension bearing of the present application comprises a rotating shaft 1, a thrust disc 2, an upper thrust disc stator 3, a first wire winding 4, a second wire winding 8, an upper thrust disc stator cover plate 5, a lower thrust disc stator 7, a lower thrust disc stator cover plate 9, a first sensor 6 and a second sensor 10. Figures 3 to 6As shown, the rotating shaft 1 and the thrust plate 2 are fixed by shrink fitting or threaded connection. The upper thrust plate stator 3 and the lower thrust plate stator 7 are fastened to the motor housing by shrink fitting or screws 11 respectively. The end faces of the upper thrust plate stator 3 and the lower thrust plate stator 7 relative to the thrust plate 2 are 0.3 to 0.6 mm apart. The first sensor 6 is embedded in the upper thrust plate stator 3, and the second sensor 10 is embedded in the lower thrust plate stator 7. The first sensor 6 and the second sensor 10 are symmetrically arranged, each 0.5 to 0.6 mm away from the end face of the thrust plate 2, and are used to detect the position of the rotating shaft in real time, and to adjust the rotor position from time to time by feeding back the current signal, so that the rotor can operate stably in suspension.

[0032] Figure 7 The figure shows the distance between the stator cover and the end face of the thrust disc. Figures 3 to 7 As shown, the outer diameter of the upper thrust plate stator cover 5 matches that of the upper thrust plate stator 3, while its inner diameter is slightly smaller than the outer diameter of the thrust plate 2. The upper thrust plate stator cover 5 is mounted on the upper thrust plate stator 3 and fastened to the upper thrust plate stator 3 with screws at its outer ring, securing the first coil 4 within the slots of the upper thrust plate stator 3. The end surface of the upper thrust plate stator cover 5 is flush with the inner ring end surface of the upper thrust plate stator 3 and is 0.3 to 0.6 mm away from the upper end surface of the thrust plate 2.

[0033] like Figures 3 to 7 As shown, the outer diameter of the lower thrust disc stator cover 9 matches that of the lower thrust disc stator 7. The inner diameter of the lower thrust disc stator cover 9 is slightly larger than the outer diameter of the thrust disc 2, for example, 1-2 mm. The lower thrust disc stator cover 9 is positioned on the lower thrust disc stator 7 and is fastened to the lower thrust disc stator 7 with screws at its outer ring, securing the second coil 8 within the slot of the lower thrust disc stator 7. The lower end surface of the lower thrust disc stator cover 9 is flush with the lower end surface of the thrust disc. Once flush, only radial forces act between the lower thrust disc stator cover 9 and the thrust disc 2, eliminating pull-off forces and further reducing the outer diameter of the thrust disc 2. The distance between the lower thrust disc stator cover 9 and the upper thrust disc stator cover 5 is greater than the gap between the lower thrust disc stator cover 9 and the thrust disc 2. This prevents interference between the upper thrust disc stator 3 and the lower thrust disc stator 7, thus reducing magnetic flux leakage. This structure ensures that the difference in electromagnetic pull on the thrust plate 2 equals the weight of the rotor itself. This creates an effective magnetic circuit between the lower thrust plate stator 7, lower thrust plate stator cover 9, and thrust plate 2, as well as between the upper thrust plate stator 3, upper thrust plate stator cover 5, and thrust plate 2. The magnetic circuits of the upper and lower magnetic bearings (thrust plate stator assembly) complement each other, minimizing ineffective magnetic leakage.

[0034] like Figures 3 to 7As shown, the first coil 4 and the second coil 8 are both copper wires wound in the thrust plate stator slots. The lower thrust plate stator 7, the upper thrust plate stator 3, the upper thrust plate stator cover 5, the lower thrust plate stator cover 9 and the thrust plate 2 are all made of soft magnetic materials.

[0035] Figure 8 FIG. 1 is a schematic diagram of the magnetic circuit of the asymmetric axial magnetic bearing of the present invention, as shown in FIG. Figure 8 As shown (the stereoscopic diagram shows one rotation along the Z axis), the lower thrust plate stator 7, upper thrust plate stator 3, upper thrust plate stator cover 5, lower thrust plate stator cover 9, and thrust plate 2 are all made of magnetically conductive materials. When current flows through the first coil 4, a magnetic field is generated in the surrounding area. The magnetic lines of force flow along, for example, the upper thrust plate stator 3 and upper thrust plate stator cover 5, into the thrust plate 2, and then back to the upper thrust plate stator 3, forming a loop, exerting an upward suction on the thrust plate. When current flows through the second coil 8, the magnetic lines of force flow along the lower thrust plate stator 7 and lower thrust plate stator cover 9, into the thrust plate 2, and then back to the lower thrust plate stator 7, forming a loop, exerting a downward suction on the thrust plate. Sensors are provided to continuously monitor the position of the thrust plate 2, feedback and adjust the current in the upper and lower thrust plate stators, thereby adjusting the force applied to the thrust plate 2, ensuring that the thrust plate 2 remains stably suspended between the upper and lower thrust plate stators.

[0036] Figure 9 The diagram shows the axial force of the thrust plate. Figure 9 As shown, due to the asymmetric structure of the upper thrust plate stator cover 5 and the lower thrust plate stator cover 9, the axial upward pulling force of the thrust plate stator on the thrust plate 2 is greater than the axial downward pulling force, so that the difference between the upper and lower pulling forces on the thrust plate is equal to the gravity of the rotor itself, achieving force balance and making the rotor suspended and stable.

[0037] like Figure 9 As shown, the axial force analysis of the thrust plate includes: the thrust plate 2 and the rotor's own gravity, and the downward magnetic pull F generated by the lower thrust plate stator 7. 下 , the upper thrust plate stator 3 generates an upward magnetic pull F 上1 and F 上2 The simplified formula of magnetic pull is F=1 / 2u*B2S, where u is the air magnetic permeability, B is the air gap magnetic density, and S is the annular area of ​​the thrust plate and the thrust plate stator. Therefore, according to the present invention, those skilled in the art can reasonably select the matching area of ​​the upper and lower thrust plate covers and the end surface of the thrust plate 2. For example, in this embodiment, the upper thrust plate stator cover 5 increases the matching area with the thrust plate 2, so that the thrust plate 2 is subjected to an additional upward magnetic pull F. 上2 , used to offset the gravity of the rotor itself.

[0038] Figure 10 The diagram shows the distance between the upper thrust plate stator and the lower thrust plate stator and the thrust plate end face. Figure 10As shown, for one embodiment, the present invention can be further adjusted so that the distance between the upper thrust plate stator 3 and the end surface of the thrust plate 2 is smaller than the distance between the lower thrust plate stator 7 and the end surface of the thrust plate 2, and the difference between the upper and lower pulling forces on the thrust plate 2 is adjusted to be equal to the rotor gravity by affecting the air gap magnetic density.

[0039] Figure 11 The figure shows the number of turns of the first line and the number of turns of the second line. Figure 11 As shown, for another embodiment, the present invention can also adjust the number of turns of the first coil 4 and the second coil 8. For example, the number of turns of the first coil 4 is greater than the number of turns of the second coil 8, and the difference between the upper and lower pulling forces on the thrust plate 2 is further adjusted to be equal to the rotor gravity.

[0040] The present invention utilizes an asymmetric design of the upper and lower thrust disc stator covers, distributing a small bias current to overcome the rotor's inherent gravity and levitate it, thus saving energy. The thrust disc's double-sided force-bearing structure ensures that the difference in upper and lower tension applied to the disc equals the rotor's inherent gravity, resulting in stable rotor operation and ease of control and adjustment. The asymmetric design of the upper and lower thrust disc stator covers ensures that the difference in upper and lower tension applied to the disc equals the rotor's inherent gravity, resulting in stable rotor operation and ease of control and adjustment. Furthermore, the sensor is located within the thrust disc stator, saving overall space.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An asymmetric axial magnetic bearing, characterized in that: include: Rotating shaft, thrust plate, upper thrust plate stator, first coil package, second coil package, upper thrust plate stator cover, lower thrust plate stator, lower thrust plate stator cover; The rotating shaft is connected to the thrust plate, and the upper thrust plate stator and the lower thrust plate stator are respectively connected to the motor housing; the upper thrust plate stator, the lower thrust plate stator and the end faces opposite to the thrust plate are respectively at a certain distance; The outer diameter of the upper thrust plate stator cover matches the outer diameter of the upper thrust plate stator, and the inner diameter of the upper thrust plate stator cover is smaller than the outer diameter of the thrust plate; the upper thrust plate stator cover is arranged on the upper thrust plate stator, and the upper thrust plate stator cover is fastened to the upper thrust plate stator so that the first coil is fixed in the space surrounded by the upper thrust plate stator and one end face of the upper thrust plate stator cover; the other end face of the upper thrust plate stator cover is flush with the inner ring end face of the upper thrust plate stator; The outer diameter of the lower thrust disc stator cover plate matches the outer diameter of the lower thrust disc stator, and the inner diameter of the lower thrust disc stator cover plate is larger than the outer diameter of the thrust disc; the lower thrust disc stator cover plate is arranged on the lower thrust disc stator, and the lower thrust disc stator cover plate is fastened to the lower thrust disc stator, so that the second coil is fixed in the space surrounded by the lower thrust disc stator and one end surface of the lower thrust disc stator cover plate, and the lower end surface of the thrust disc is flush with the end surface of the lower thrust disc stator cover plate, and the distance between the lower thrust disc stator cover plate and the upper thrust disc stator cover plate is larger than the gap between the lower thrust disc stator cover plate and the thrust disc; When the current changes, a magnetic circuit is formed between the upper thrust plate stator, the upper thrust plate stator cover, and the thrust plate, and the thrust plate is subjected to an upward magnetic pull, while a magnetic circuit is formed between the lower thrust plate stator, the lower thrust plate stator cover, and the thrust plate, and the thrust plate is subjected to a downward magnetic pull; the difference in the electromagnetic pull on the thrust plate is equal to the gravity of the rotor itself.

2. The asymmetric axial magnetic bearing according to claim 1, characterized in that: Also includes: The first sensor and the second sensor are embedded in the upper thrust plate stator and the second sensor is embedded in the lower thrust plate stator. The first sensor and the second sensor are symmetrically arranged and are used to detect the rotor position.

3. The asymmetric axial magnetic bearing according to claim 2, characterized in that: The first sensor and the second sensor are respectively 0.5 to 0.6 mm away from the upper and lower end surfaces of the thrust plate.

4. The asymmetric axial magnetic bearing according to claim 1, characterized in that: The rotating shaft and the thrust plate are fixed by shrink fitting or threaded connection; The upper thrust plate stator and the lower thrust plate stator are fastened to the housing by shrink fitting or screws respectively; The outer ring of the lower thrust plate stator cover is fastened to the lower thrust plate stator by screws, and the outer ring of the upper thrust plate stator cover is fastened to the upper thrust plate stator by screws; The upper thrust plate stator and the lower thrust plate stator are respectively 0.3-0.6 mm away from the end faces opposite to the thrust plate.

5. The asymmetric axial magnetic bearing according to claim 1, characterized in that: The first wire package and the second wire package are made of copper wire material. The first wire package is arranged in the stator slot of the upper thrust plate, and the second wire package is arranged in the stator slot of the lower thrust plate.

6. The asymmetric axial magnetic bearing according to claim 1, characterized in that: The lower thrust plate stator, the upper thrust plate stator, the upper thrust plate stator cover, the lower thrust plate stator cover and the thrust plate are made of soft magnetic materials.

7. The asymmetric axial magnetic bearing according to claim 1, characterized in that: When current flows through the first coil, the path of the magnetic lines of force is the upper thrust plate stator, the upper thrust plate stator cover, into the thrust plate, and then back to the upper thrust plate stator, forming a loop and exerting an upward suction on the rotor. When current flows through the second coil, the path of the magnetic lines of force is the lower thrust plate stator, the lower thrust plate stator cover, enters the thrust plate, and then returns to the lower thrust plate stator, forming a loop and exerting downward suction on the rotor.

8. The asymmetric axial magnetic bearing according to claim 1, wherein: The upper thrust plate stator cover, the lower thrust plate stator cover and the end surface area of ​​the thrust plate are matched so that when current is passed through the first coil or the second coil, the axial upward pulling force of the thrust plate stator on the thrust plate is greater than the axial downward pulling force, so that the difference between the upper and lower pulling forces on the thrust plate is equal to the gravity of the rotor itself, achieving force balance and making the rotor suspended and stable.

9. The asymmetric axial magnetic bearing according to claim 1, wherein: The distance between the upper thrust plate stator and one end surface of the thrust plate is smaller than the distance between the lower thrust plate stator and the other end surface of the thrust plate.

10. The asymmetric axial magnetic bearing according to claim 1, characterized in that: The number of turns of the first wire is different from the number of turns of the second wire to adjust the difference between the upper and lower pulling forces on the thrust plate.

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