A small-volume, low-power radial-axial integrated magnetic bearing structure

Abstract

The present invention relates to the technical field of non-contact magnetic suspension bearings, and in particular to a compact, low-power, radial-axial integrated magnetic bearing structure. The structure comprises a rotor shaft, an axial passive magnetic bearing and a radial active magnetic bearing coaxially sleeved on the outer side of the rotor shaft. The axial passive magnetic bearing and the radial active magnetic bearing are located at opposite ends of the rotor shaft, and are connected by an axial magnetic guide ring coaxially disposed with the rotor shaft. The present invention can reduce the size of the magnetic bearing, achieve high axial passive stiffness, and reduce the losses of existing active magnetic bearings under high-stiffness loads.

Description

Technical Field

[0001] The present invention relates to the technical field of non-contact magnetic suspension bearings, and in particular to a small-volume, low-power, radial-axial integrated magnetic bearing structure. Background Art

[0002] Magnetic bearing is a new type of high-performance support structure with the advantages of non-contact, frictionless, high speed, active control, and online monitoring. It is an ideal support method for high-precision, long-life, and high-speed rotor systems.

[0003] Magnetic bearings are categorized as active and passive. Active magnetic bearings provide variable stiffness and damping to the suspended rotor, actively suppressing rotor vibration and achieving extremely low rotor vibration. However, active magnetic bearings are unstable in the open loop and require a closed-loop feedback control system consisting of sensors, controllers, and amplifiers. This consumes a lot of power and is affected by the space environment and electronic components, resulting in low reliability. Passive magnetic bearings rely on the forces between permanent magnets or the magnetic resistance between permanent magnets and magnetic materials for suspension support, and the suspension force cannot be actively controlled. However, passive magnetic bearings have a simple structure, require no control system, consume no energy, and are highly reliable. Active-passive hybrid magnetic bearings combine the characteristics of these two types of magnetic bearings, using active magnetic bearings for control in degrees of freedom where precision and stability are critical, and passive magnetic bearings for support in degrees of freedom where control performance is less stringent. This approach reduces power consumption and size while increasing load capacity.

[0004] However, there are the following deficiencies in the prior art:

[0005] For example, patent number 201510850827.6, patent name is a contactless active-passive hybrid control horizontal axial positioning device, and patent number 201510271298.4, patent name is a magnetic circuit decoupled permanent magnet biased active and passive hybrid radial magnetic levitation bearing. Both adopt an active-passive hybrid magnetic bearing structure. The passive part and the active part do not share the same magnetic circuit, but are integrated in physical space. Two electromagnetically independent structures are used to achieve joint control. This method requires more electromagnetic components, does not fully utilize the magnetomotive force of the permanent magnet, and is large in size, which is not conducive to achieving system optimization design.

[0006] For example, patent 201510017297.7, titled "A Permanent Magnet Biased Outer Rotor Four-Degree-of-Freedom Active-Passive Hybrid Magnetic Bearing," utilizes an active-passive hybrid magnetic bearing structure. While partially sharing the permanent magnet magnetic circuit, this is achieved through the magnetic resistance between the stator and rotor cores of equal axial length. Passive magnetic bearings lack permanent magnets at their poles, resulting in low passive stiffness and inability to meet high load-bearing capacity requirements.

[0007] Therefore, a small-volume, low-power, radial-axial integrated magnetic bearing structure is urgently needed to solve the problem. Summary of the Invention

[0008] The purpose of the present invention is to provide a small-volume, low-power radial-axial integrated magnetic bearing structure to solve the above-mentioned problems.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] A small-volume, low-power radial-axial integrated magnetic bearing structure comprises: a rotor shaft, an outer coaxial sleeve of the rotor shaft is provided with an axial passive magnetic bearing and a radial active magnetic bearing, the axial passive magnetic bearing and the radial active magnetic bearing are respectively located at two ends of the rotor shaft, the axial passive magnetic bearing and the radial active magnetic bearing are connected by an axial magnetic guide ring, and the axial magnetic guide ring is coaxially arranged with the rotor shaft.

[0011] Preferably, the axial passive magnetic bearing includes a rotor permanent magnet coaxially fixed to the outer wall of the rotor shaft, the rotor permanent magnet is located at one end of the rotor shaft, and a stator permanent magnet is coaxially sleeved on the outer side of the rotor permanent magnet. A passive magnetic pole gap is left between the stator permanent magnet and the rotor permanent magnet, and the S pole of the stator permanent magnet is close to the N pole of the rotor permanent magnet.

[0012] Preferably, the radial active magnetic bearing includes a radial magnetic pole rotor coaxially fixed to the outer side wall of the rotor shaft, the radial magnetic pole rotor is located at the end of the rotor shaft away from the rotor permanent magnet, a radial stator core is provided at the outer edge of the radial magnetic pole rotor, the radial stator core and the radial magnetic pole rotor are coaxially arranged, and a radial magnetic pole gap is left between the radial stator core and the radial magnetic pole rotor.

[0013] Preferably, the radial stator core includes a plurality of magnetic poles, which are arranged at equal intervals in the circumferential direction, and a magnetic pole connecting yoke is coaxially fixed to the outer edges of the plurality of magnetic poles. A radial coil is wound around the outer side of the magnetic pole, and the axis of the radial coil is located on the straight line where the diameter of the magnetic pole connecting yoke is located.

[0014] Preferably, a radial magnetic conductive ring is coaxially fixed to the outer edge of the stator permanent magnet, and the radial magnetic conductive ring is fixed to the magnetic pole connecting yoke via the axial magnetic conductive ring.

[0015] Preferably, the material of the stator permanent magnet and the rotor permanent magnet includes one of ferrite permanent magnet material and rare earth permanent magnet material.

[0016] Preferably, the material of the radial magnetic conductive ring and the axial magnetic conductive ring includes one of electrical pure iron and low carbon steel.

[0017] Preferably, the material of the radial stator core includes one of silicon steel, 1J50, and 1J22.

[0018] Preferably, the material of the rotor shaft includes 40Cr.

[0019] The present invention has the following technical effects:

[0020] The present invention proposes an active and passive hybrid magnetic bearing structure. An axial passive magnetic bearing and a radial active magnetic bearing are respectively provided at both ends of the rotor shaft. The axial passive magnetic bearing and the radial active magnetic bearing are connected via an axial magnetic guide ring. A connected permanent magnetic circuit is formed between the axial passive magnetic bearing and the radial active magnetic bearing, and the axial passive magnetic bearing and the radial active magnetic bearing share the permanent magnetic flux, thereby reducing the volume of the magnetic bearing.

[0021] Through the polar position relationship between the rotor permanent magnet and the stator permanent magnet, an axial restoring force is formed between the rotor permanent magnet and the stator permanent magnet, which plays the role of axial passive suspension, achieves high axial passive stiffness, and reduces the loss of existing active magnetic bearings under high stiffness loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is the front view of the present invention;

[0024] Figure 2 It is a bottom view of the present invention;

[0025] Figure 3 Schematic diagram of the magnetic path of the axial passive magnetic bearing part of the present invention;

[0026] Figure 4 Schematic diagram of the magnetic path of the radial active magnetic bearing part of the present invention;

[0027] Among them, 1. rotor shaft; 2. rotor permanent magnet; 3. passive magnetic pole gap; 4. stator permanent magnet; 5. radial magnetic guide ring; 6. axial magnetic guide ring; 7. radial stator core; 8. radial coil; 9. radial magnetic pole gap; 10. radial magnetic pole rotor; 11. magnetic pole connecting yoke. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Reference Figure 1-4 The present invention provides a small-volume, low-power radial-axial integrated magnetic bearing structure, comprising: a rotor shaft 1, an outer coaxial sleeve of the rotor shaft 1 is provided with an axial passive magnetic bearing and a radial active magnetic bearing, the axial passive magnetic bearing and the radial active magnetic bearing are respectively located at both ends of the rotor shaft 1, the axial passive magnetic bearing and the radial active magnetic bearing are connected by an axial guide magnetic ring 6, and the axial guide magnetic ring 6 is coaxially arranged with the rotor shaft 1.

[0031] This device proposes an active and passive hybrid magnetic bearing structure, by arranging an axial passive magnetic bearing and a radial active magnetic bearing at both ends of the rotor shaft 1, and connecting the axial passive magnetic bearing and the radial active magnetic bearing through an axial magnetic guide ring 6, so that a connected permanent magnetic circuit is formed between the axial passive magnetic bearing and the radial active magnetic bearing, so that the axial passive magnetic bearing and the radial active magnetic bearing share the permanent magnetic flux, thereby reducing the volume of the magnetic bearing.

[0032] A further optimized solution is provided, in which the axial passive magnetic bearing includes a rotor permanent magnet 2 coaxially fixed to the outer wall of the rotor shaft 1. The rotor permanent magnet 2 is located at one end of the rotor shaft 1, and a stator permanent magnet 4 is coaxially sleeved on the outer side of the rotor permanent magnet 2. A passive magnetic pole gap 3 is left between the stator permanent magnet 4 and the rotor permanent magnet 2, and the S pole of the stator permanent magnet 4 is close to the N pole of the rotor permanent magnet 2.

[0033] The north pole of the rotor permanent magnet 2 and the south pole of the stator permanent magnet 4 are close to each other, creating an attractive force between the rotor permanent magnet 2 and the stator permanent magnet 4, which acts as an axial passive suspension, achieving high axial passive stiffness and reducing the losses of existing active magnetic bearings under high stiffness loads. The rotor permanent magnet 2 and the stator permanent magnet 4 are both annular and concentrically arranged. The axial lengths of the rotor permanent magnet 2 and the stator permanent magnet 4 are equal and axially aligned. The south pole of the stator permanent magnet 4 can be close to the north pole of the rotor permanent magnet 2, and the north pole of the stator permanent magnet 4 can be close to the south pole of the rotor permanent magnet 2. It is only necessary to ensure that there is an attractive force between the rotor permanent magnet 2 and the stator permanent magnet 4. The width of the passive magnetic pole gap 3 is 1mm to 2mm.

[0034] A further optimized solution is provided, in which the radial active magnetic bearing includes a radial magnetic pole rotor 10 coaxially fixed to the outer wall of the rotor shaft 1. The radial magnetic pole rotor 10 is located at the end of the rotor shaft 1 away from the rotor permanent magnet 2. A radial stator core 7 is provided at the outer edge of the radial magnetic pole rotor 10. The radial stator core 7 and the radial magnetic pole rotor 10 are coaxially arranged, with a radial magnetic pole gap 9 being left between the radial stator core 7 and the radial magnetic pole rotor 10. The width of the radial magnetic pole gap 9 is 0.5 mm to 1 mm.

[0035] In a further optimized solution, the radial stator core 7 includes a plurality of magnetic poles, which are evenly spaced circumferentially. A magnetic pole connection yoke 11 is coaxially fixed to the outer edges of the magnetic poles. A radial coil 8 is wound around the outer edges of the magnetic poles, with the axis of the radial coil 8 lying along a straight line extending from the diameter of the magnetic pole connection yoke 11. The number of magnetic poles is preferably four, and the radial coil 8 is preferably made of copper wire with a diameter of 0.2 mm to 1 mm.

[0036] According to a further optimized solution, a radial magnetic conductive ring 5 is coaxially fixed to the outer edge of the stator permanent magnet 4 , and the radial magnetic conductive ring 5 is fixed to the magnetic pole connection yoke 11 via an axial magnetic conductive ring 6 .

[0037] According to a further optimization scheme, the material of the stator permanent magnet 4 and the rotor permanent magnet 2 includes one of ferrite permanent magnet material and rare earth permanent magnet material.

[0038] According to a further optimization scheme, the material of the radial magnetic guide ring 5 and the axial magnetic guide ring 6 includes one of electrical pure iron and low carbon steel.

[0039] According to a further optimization scheme, the material of the radial stator core 7 includes one of silicon steel, 1J50, and 1J22.

[0040] According to a further optimization solution, the material of the rotor shaft 1 includes 40Cr.

[0041] The working process of this device is as follows:

[0042] Reference Figure 3 In an axial passive magnetic bearing, the magnetic flux generated by the permanent magnets originates from the north pole of the rotor permanent magnet 2, passes through the passive magnetic pole gap 3, the stator permanent magnet 4, the radial magnetic guide ring 5, the axial magnetic guide ring 6, the radial stator core 7, the radial magnetic pole gap 9, the radial magnetic pole rotor 10, the rotor shaft 1, and finally returns to the south pole of the rotor permanent magnet 2. The permanent magnets form a working magnetic flux in the passive magnetic pole gap 3, which provides the passive suspension force for axial translational freedom. Simultaneously, the permanent magnets form a working magnetic flux in the radial magnetic pole gap 9, which provides the bias magnetic flux for the radial active magnetic bearing.

[0043] Reference Figure 4In a radial active magnetic bearing, taking the magnetic flux generated by energizing radial coil 8 on the Y-direction magnetic pole as an example, the electromagnetic field passes through the Y+ radial magnetic pole gap 9, the magnetic poles of the Y+ radial stator core 7, the magnetic pole connecting yoke 11, the magnetic poles of the Y-direction radial stator core 7, the Y-direction radial magnetic pole gap 9, and finally through the radial magnetic pole rotor 10 to form a closed loop. When a radial disturbance occurs on the rotor shaft 1, a regulating magnetic field is generated by controlling the current in radial coil 8. This magnetic field, combined with the bias magnetic field generated by the permanent magnets, changes the strength of the magnetic field in the radial magnetic pole gap 9, thereby generating an actively adjustable radial electromagnetic force.

[0044] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0045] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A small-volume, low-power radial-axial integrated magnetic bearing structure, characterized in that: include: A rotor shaft (1), wherein an axial passive magnetic bearing and a radial active magnetic bearing are coaxially sleeved on the outer side of the rotor shaft (1), the axial passive magnetic bearing and the radial active magnetic bearing are respectively located at two ends of the rotor shaft (1), the axial passive magnetic bearing and the radial active magnetic bearing are connected via an axial magnetic guide ring (6), and the axial magnetic guide ring (6) is coaxially arranged with the rotor shaft (1); The axial passive magnetic bearing comprises a rotor permanent magnet (2) coaxially fixed to the outer wall of the rotor shaft (1), the rotor permanent magnet (2) being located at one end of the rotor shaft (1), a stator permanent magnet (4) being coaxially sleeved on the outer side of the rotor permanent magnet (2), a passive magnetic pole gap (3) being left between the stator permanent magnet (4) and the rotor permanent magnet (2), and the S pole of the stator permanent magnet (4) being close to the N pole of the rotor permanent magnet (2); The radial active magnetic bearing comprises a radial magnetic pole rotor (10) coaxially fixed to the outer wall of the rotor shaft (1), the radial magnetic pole rotor (10) being located at an end of the rotor shaft (1) away from the rotor permanent magnet (2), a radial stator core (7) being provided at the outer edge of the radial magnetic pole rotor (10), the radial stator core (7) being coaxially arranged with the radial magnetic pole rotor (10), and a radial magnetic pole gap (9) being left between the radial stator core (7) and the radial magnetic pole rotor (10); The radial stator core (7) includes a plurality of magnetic poles, the plurality of magnetic poles being arranged at equal intervals in the circumferential direction, a magnetic pole connection yoke (11) being coaxially fixed to the outer edges of the plurality of magnetic poles, a radial coil (8) being wound around the outer sides of the magnetic poles, and an axis of the radial coil (8) being located on a straight line where the diameter of the magnetic pole connection yoke (11) is located; A radial magnetic conductive ring (5) is coaxially fixed to the outer edge of the stator permanent magnet (4), and the radial magnetic conductive ring (5) is fixed to the magnetic pole connection yoke (11) via the axial magnetic conductive ring (6); In the axial passive magnetic bearing, the magnetic flux starts from the N pole of the rotor permanent magnet (2), passes through the passive magnetic pole gap (3), the stator permanent magnet (4), the radial magnetic guide ring (5), the axial magnetic guide ring (6), the radial stator core (7), the radial magnetic pole gap (9), the radial magnetic pole rotor (10), the rotor shaft (1), and finally returns to the S pole of the rotor permanent magnet (2), forming a working magnetic flux at the passive magnetic pole gap (3) to provide a passive suspension force for the axial translational freedom degree; at the same time, a working magnetic flux is formed at the radial magnetic pole gap (9), providing a bias magnetic flux for the radial active magnetic bearing; In the radial active magnetic bearing, the radial coil (8) on the Y-direction magnetic pole generates magnetic flux after being energized, and the electromagnetic magnetic field passes through the radial magnetic pole gap (9) in the Y+ direction, the magnetic pole of the radial stator core (7) in the Y+ direction, the magnetic pole connecting yoke (11), the magnetic pole of the radial stator core (7) in the Y-direction, the radial magnetic pole gap (9) in the Y-direction, and finally forms a closed loop through the radial magnetic pole rotor (10); when the rotor shaft (1) experiences radial disturbance, an adjustment magnetic field is formed by controlling the current in the radial coil (8), and the magnetic field is superimposed on the bias magnetic field generated by the permanent magnet to change the strength of the magnetic field in the radial magnetic pole gap (9), thereby generating an actively adjustable radial electromagnetic force.

2. The small-volume, low-power radial-axial integrated magnetic bearing structure according to claim 1, characterized in that: The material of the stator permanent magnet (4) and the rotor permanent magnet (2) includes one of ferrite permanent magnet material and rare earth permanent magnet material.

3. The small-volume, low-power radial-axial integrated magnetic bearing structure according to claim 1, characterized in that: The material of the radial magnetic conductive ring (5) and the axial magnetic conductive ring (6) includes one of electrical pure iron and low carbon steel.

4. The small-volume, low-power radial-axial integrated magnetic bearing structure according to claim 1, characterized in that: The material of the radial stator core (7) includes one of silicon steel, 1J50 and 1J22.

5. The small-volume, low-power radial-axial integrated magnetic bearing structure according to claim 1, characterized in that: The material of the rotor shaft (1) includes 40Cr.

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