Magnetic bearing device and method for generating an axial levitation repulsion force

Abstract

The application discloses a magnetic suspension bearing device, which comprises a thrust bearing, an excitation disc and a conductor disc, the conductor disc is wound outside the thrust bearing, the excitation disc and the conductor disc are embedded with each other and are wound on a transmission shaft, the excitation disc is a permanent magnet, and the conductor disc is provided with a hollow coil and a core coil. When the excitation disc rotates along the transmission shaft, a rotating magnetic field rotating around the transmission shaft is generated, the hollow coil and the core coil in the conductor disc generate induced electromotive force under the action of the rotating magnetic field, an induced magnetic field with the same direction as the magnetic pole direction of the excitation disc is outputted, and thus a suspension repulsive force resisting the axial load is generated. The device can reduce the complexity and cost of the magnetic suspension device control and improve the linear consistency resisting the axial load.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic suspension bearing, in particular to a magnetic suspension bearing device and a method for generating axial suspension repulsion. BACKGROUND

[0002] For large power equipment, such as large pump units, wind turbines, hydroelectric generators, air blowers, etc., when the transmission shaft rotates, it will bear axial and radial loads. If the axial load is too large, it will cause the thrust bearing to collapse and fail, making the equipment unstable.

[0003] For example, when the wind blade of a wind turbine encounters strong airflow, vibration will generate axial vibration, especially when the axial vibration approaches the natural frequency, which will cause a huge impact on the axial thrust bearing, causing damage to the bearing assembly and affecting the power generation efficiency and service life of the generator.

[0004] Magnetic suspension bearing is a kind of bearing that uses magnetic force to realize the bearing movement part and the relative static part without friction bearing. It is divided into active magnetic suspension bearing and passive magnetic suspension bearing.

[0005] The existing active magnetic suspension technology usually uses electromagnetic induction principle to generate electromagnetic oscillation under the action of electricity through a closed-loop control system, and then generates a magnetic field through an electromagnetic coil. The suspension force is generated by the interaction of the magnetic field to isolate the transmission mechanism and the motor, thereby reducing wear and tear. However, this active magnetic suspension device requires a complex control loop and has poor load stability. The existing passive magnetic suspension bearing relies on the magnetic force of permanent magnets to bear the axial load and make it float. It does not require additional power supply and energy consumption, and can use multiple permanent magnets to achieve the suspension of the device. However, the generated suspension magnetic chain cannot change linearly with the size of the external axial load. SUMMARY

[0006] In view of the above problems, the present application provides a magnetic suspension bearing device which can reduce the control complexity of electromagnetic magnetic suspension devices and increase the linear consistency of the axial load resistance of permanent magnetic suspension bearings. It can provide a linearly consistent load resistance suspension force according to the speed, thereby improving the stability of the operation of the power equipment.

[0007] According to a first aspect of the present application, a magnetic suspension bearing device is provided, comprising a thrust bearing, an excitation disc and a conductor disc, the conductor disc being wound outside the thrust bearing, the excitation disc and the conductor disc being embedded with each other and wound on the transmission shaft, the excitation disc being a permanent magnet, and the conductor disc being provided with a hollow coil and an iron core coil.

[0008] Optionally, in the magnetic suspension bearing device, the core of the core coil is made of any one of silicon steel sheet, permalloy, amorphous soft magnetic alloy, and nanocrystalline alloy, and the excitation disc is made of any one of neodymium iron boron, samarium cobalt, aluminum nickel cobalt, and ferrite.

[0009] Optionally, in the magnetic suspension bearing device, the excitation disc generates a rotating magnetic field along the rotating transmission shaft when rotating with the transmission shaft, the hollow coil and the core coil generate superimposed induced electromotive force under the action of the rotating magnetic field, and the core coil and the hollow coil generate superimposed induced electromotive force under the action of the pulsating direct current, and output an induced magnetic field with the same direction as the magnetic pole direction of the permanent magnet.

[0010] Optionally, in the magnetic suspension bearing device, the induced magnetic field and the magnetic field of the permanent magnet form a suspension magnetic chain, and the generated suspension repulsive force is conducted out through the core of the core coil.

[0011] Optionally, in the magnetic suspension bearing device, the suspension repulsive force is opposite to the direction of the axial load, and the size of the suspension repulsive force increases with the increase of the axial load and decreases with the decrease of the axial load.

[0012] Optionally, in the magnetic suspension bearing device, an axial position limiter and a closed shell are further included, the axial position limiter is used to fix the axial position of the excitation disc and the conductor disc on the transmission shaft, and the closed shell is used to cover the excitation disc and the conductor disc.

[0013] According to the second aspect of the present application, an axial suspension repulsive force generation method is provided, which is realized by the magnetic suspension bearing device as claimed in the above, and includes: when the transmission shaft rotates, the excitation disc rotates around the transmission shaft to generate a rotating magnetic field; under the action of the rotating magnetic field, the hollow coil and the core coil in the conductor disc generate superimposed induced electromotive force, and output an induced magnetic field with the same direction as the magnetic pole direction of the permanent magnet; the induced magnetic field and the magnetic field of the permanent magnet form a suspension magnetic chain, and generate a suspension repulsive force with the same size and opposite direction as the axial load; with the increase of the rotating speed of the transmission shaft, the superimposed induced electromotive force in the conductor disc increases, and the size of the suspension repulsive force increases with the increase of the axial load and decreases with the decrease of the axial load.

[0014] Optionally, in the axial suspension repulsive force generation method, when the rotating speed of the transmission shaft is less than a preset threshold value, the induced electromotive force generated by the hollow coil provides the suspension repulsive force against the axial load, and when the rotating speed of the transmission shaft is greater than the preset threshold value, the superimposed induced electromotive force of the hollow coil and the core coil jointly provides the suspension repulsive force against the axial load.

[0015] The magnetic suspension bearing device provided by the application can automatically improve excitation capacity according to the high or low rotating speed, provide suspension force resisting bearing load linearly consistent with the bearing load, effectively block vibration and solve the problems of complex power supply and poor stability of conventional magnetic suspension devices.

[0016] The above description is only a summary of the technical scheme of the application, in order to more clearly understand the technical means of the application, the content of the specification can be implemented, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the following specific embodiments of the application are described. BRIEF DESCRIPTION OF DRAWINGS

[0017] Various other advantages and benefits will become apparent to those of ordinary skill in the art, upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not meant to limit the present application. Furthermore, the same reference numerals are intended to denote the same components throughout the accompanying drawings. In the drawings:

[0018] Figure 1 A structural schematic diagram of a magnetic suspension bearing device according to one embodiment of the application is shown;

[0019] Figure 2 An end surface structure schematic diagram of a conductor disk according to one embodiment of the application is shown;

[0020] Figure 3 An end surface structure schematic diagram of an excitation disk according to one embodiment of the application is shown;

[0021] Figure 4 A vortex circuit topology diagram according to one embodiment of the application is shown;

[0022] Figure 5 A flowchart of an axial suspension magnetic force generation method according to one embodiment of the application is shown. DETAILED DESCRIPTION

[0023] Exemplary embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. While example embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be embodied in various forms without being limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thoroughly and completely understood, and so that the scope of the present disclosure will be completely conveyed to those skilled in the art.

[0024] Shaft is a mechanical component that is worn in the middle of the bearing to support the rotating part and rotates with it to transmit motion and torque. Large power equipment will cause damage to the shaft and bearing due to large axial pressure load when rotating at high speed, affecting the service life of the product. Among them, the axial load refers to the load generated in the axial direction of the bearing, which widely exists in various structural vibrations. Therefore, the axial suspension repulsive force can be generated by the magnetic suspension technology to reduce the axial load.

[0025] Conventional magnetic suspension bearings usually need complex electronic control technology to generate a suspension magnetic chain, for example, when the rotor is disturbed downward, it will deviate from its reference position, at this time the sensor detects the displacement of the rotor deviating from the reference point, and the microcontroller converts the detected displacement into a control signal. The power amplifier converts this control signal into a control current, which generates a magnetic force in the executing magnet, thereby driving the rotor to return to the original equilibrium position.

[0026] Such magnetic suspension bearings need to generate electromagnetic oscillation under the action of electricity through the control system, then generate a magnetic field through the electromagnetic coil, and generate suspension through the interaction of the magnetic field, and need a complex closed-loop control circuit to realize the linear consistency of the load and the suspension magnetic force.

[0027] While the permanent magnet suspension bearing can work without external power supply and energy consumption, it cannot provide axial repulsive force with linear consistency with the axial load, and cannot guarantee the stable operation of the power equipment.

[0028] In order to reduce the power supply and control complexity of the magnetic suspension device, and improve the linear consistency of the axial load, the present scheme provides a magnetic suspension bearing device, which generates a rotating magnetic field by rotating a permanent magnet, generates a superimposed induced electromotive force in a conductor disc formed by a combination of a hollow coil and an iron core coil under the action of the rotating magnetic field, forms a suspension magnetic chain with the same direction as the excitation magnetic chain, and forms an axial repulsive force; and can automatically adjust the excitation ability according to the speed of the transmission shaft, generate an axial repulsive force with linear consistency with the axial load, reduce the wear between the bearing and the shaft, and thus improve the stability of the transmission mechanism. The magnetic suspension bearing device has simple structure, low cost and easy maintenance, and is suitable for various large power equipment.

[0029] Figure 1 The structure of the magnetic suspension bearing device according to an embodiment of the present application is shown. As shown in Figure 1 The magnetic suspension bearing device includes a thrust bearing, an excitation disc and a conductor disc. The conductor disc is wound outside the thrust bearing, and the excitation disc and the conductor disc are embedded with each other and wound on the transmission shaft, and the diameters are substantially the same. The excitation disc is a permanent magnet, and the conductor disc is provided with a hollow coil and an iron core coil (not shown) inside. Figure 1

[0030] ​It may also include an axial limiter and a closed housing. The axial limiter is used to fix the axial position of the excitation disk and the conductor disk on the drive shaft, and the closed housing is used to cover the excitation disk and the conductor disk to reduce external electromagnetic interference.

[0031] The excitation disk is a permanent magnet made of materials such as ferrite, samarium cobalt, neodymium iron boron, and AlNiCo alloy. As the driving element, the excitation disk generates a rotating magnetic field around the drive shaft. The core of the iron core coil is made of any one of the following soft magnetic materials: silicon steel sheet, permalloy, amorphous soft magnetic alloy, or nanocrystalline alloy. These materials have high permeability, reducing the air gap between the iron core and the permanent magnet of the excitation disk, thus ensuring the coupling strength between the induced magnetic field and the permanent magnet's magnetic field.

[0032] Figure 2 A schematic diagram of the conductor disk end face structure according to an embodiment of the present invention is shown. Figure 2 As shown, the end face of the conductor disk and the excitation disk embedded part includes an excitation body surface and a magnetic conductor surface. The other end face is provided with a main carrier and an embedding slot for embedding the hollow coil and the iron core coil, and for transmitting energy through the hollow coil and the iron core coil.

[0033] Figure 3 A schematic diagram of the excitation disk end face structure according to an embodiment of the present invention is shown. Figure 3 As shown, the embedded part of the excitation disk and conductor disk is equipped with an eddy current generator, an upper fixed plate for the generator, and an upper protective plate for the generator. The eddy current generator is composed of an iron core and an excitation coil. A radial rib cover plate is provided on the other side of the excitation disk and is fixed to the drive shaft by an axial limiter.

[0034] When the excitation disk rotates along the drive shaft, it generates a rotating magnetic field around the drive shaft. Under the action of the rotating magnetic field, the hollow coil and iron core coil in the conductor disk cut the magnetic field lines to generate an induced electromotive force, which generates eddy currents in the coil. The induced magnetic field generated by the eddy currents is in the same direction as the magnetic pole of the permanent magnet of the excitation disk. The induced magnetic field and the magnetic field of the permanent magnet form a levitation magnetic chain. The resulting levitation repulsive force is conducted out through the iron core of the iron core coil, thereby outputting an axial levitation repulsive force that is opposite in direction and equal in magnitude to the axial load.

[0035] The rotational frequency of the magnetic field can be calculated from the rotational speed and the number of pole pairs, i.e., f = NP / 60, where N is the rotational speed and P is the number of pole pairs. Based on the relationship between magnetic force and magnetic flux density, rotational angular velocity, radius of the rotating body, and conductor resistance, we have F = nB²L²V / R = nB²L²ωr cos θ / R, where V is the relative velocity between the conductor disk and the excitation disk. The direction of the magnetic force is perpendicular to the direction of rotation. The magnitude of the magnetic force is directly proportional to the square of the effective length L² of the conductor cutting the magnetic field lines, the square of the magnetic flux density B², the angular velocity ω, and the radius r of the rotating body, and inversely proportional to the conductor resistance R.

[0036] Therefore, the induced magnetic field and the permanent magnet magnetic field form a suspension magnetic chain, and the size of the induced magnetic field increases with the increase of the rotating speed, thereby providing a suspension repulsive force against the axial load which is linearly consistent with the axial load, and the suspension repulsive force is flexible and linearly consistent with the axial load.

[0037] Due to the hollow coil and the core coil arranged in the conductor disc, under the action of the rotating magnetic field, the induced electromotive force E1 generated by the core coil and the self-induced electromotive force E2 generated by the hollow coil are superimposed in series as E=E1+E2. Since the two coils have the same angular speed, they have the same period and frequency, and under the condition that the applied magnetic field is the same, the induced electromotive forces generated are the same, that is, E1=E2, therefore, the superimposed electromotive force E=2E1. After the superposition of the induced electromotive force, the suspension repulsive force against the axial load is formed in the core and conducted out through the core of the core coil.

[0038] In order to generate excitation eddy current in the conductor disc, the hollow coil and the core coil in the conductor disc are cross-connected, and excitation eddy current is generated in the hollow coil and the core coil under the action of the rotating magnetic field. The excitation eddy current forms a pulsating direct current after shaping, and the core coil and the hollow coil generate superimposed induced electromotive force under the action of the pulsating direct current. Figure 4 A vortex circuit topology diagram according to an embodiment of the present application is shown. As shown in Figure 4 The hollow coil L1 and the core coil L2 are rectified by the diode D1 to generate a single-phase pulsating direct current, and the full-wave E=|A sinx | (the initial phase is zero) is rectified to a half-wave E=A sinx (E≥0, the initial phase is zero).

[0039] The direction of the axial suspension repulsive force is opposite to the direction of the axial load, and the size is linearly consistent with the size of the axial load, that is, the size of the magnetic force increases with the increase of the axial load and decreases with the decrease of the axial load.

[0040] Figure 5 A flowchart of an axial suspension magnetic force generation method according to an embodiment of the present application is shown. As shown in Figure 5 The method comprises:

[0041] When the transmission shaft rotates, the excitation disc rotates around the transmission shaft to generate a rotating magnetic field;

[0042] Under the action of the rotating magnetic field, the superimposed induced electromotive force is generated in the hollow coil and the core coil in the conductor disc, and the induced magnetic field with the same direction as the magnetic pole direction of the permanent magnet is output;

[0043] The induced magnetic field and the permanent magnet magnetic field form a suspension magnetic chain, and generate a suspension repulsive force with the same size and opposite direction as the axial load;

[0044] With the increase of the rotating speed of the transmission shaft, the superimposed induced electromotive force in the conductor disk increases, and the suspension repulsive force increases with the increase of the axial load and decreases with the decrease of the axial load.

[0045] According to one embodiment of the present application, when the rotating speed of the transmission shaft is less than a preset threshold, the induced electromotive force generated by the hollow coil provides the suspension repulsive force against the axial load, and when the rotating speed of the transmission shaft is greater than the preset threshold, the superimposed induced electromotive force of the hollow coil and the core coil jointly provides the suspension repulsive force against the axial load.

[0046] Due to the presence of the permanent magnet, at low rotating speed (for example, low wind speed of wind power), the permanent magnet provides the suspension force, and with the increase of the rotating speed, the friction of the contact surface increases, which causes the increase of heat, and the high heat damages the oil film protection of the thrust bearing, at this time, the suspension repulsive force increases, which can eliminate the wear of the bearing and the shaft and improve the service life and reliability of the bearing.

[0047] According to the magnetic suspension bearing device provided by the present application, the structure is relatively simple and the cost is low, which can not only reduce the power supply and control complexity of the electromagnetic magnetic suspension device, but also provide the anti-load suspension force linearly consistent with the axial load according to the high or low rotating speed, improve the stability of the operation of the power equipment, automatically improve the excitation capacity according to the high or low rotating speed, effectively block the vibration, and solve the problems of complex power supply and poor linear consistency of the existing magnetic suspension device.

[0048] The magnetic suspension bearing device provided by the present application can be applied to wind power generation, water power generation, air blower, pulverizer and other various large power transmission mechanisms, vertical rotor part of unmanned aerial vehicle and other equipment, and solves the problems of poor equipment reliability and high maintenance cost.

[0049] In the description provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some examples, well-known methods, structures and techniques are not shown in detail in order not to obscure the understanding of the present description.

[0050] Similarly, it should be appreciated that the various illustrative embodiments described above in the specification can relate to one or more aspects of the application, and that the various illustrative embodiments do not necessarily have to relate to the same aspect of the application, and that they can provide independent and separate advantages. Furthermore, the illustrative embodiments described in the specification can be implemented and / or combined in any way and / or number.

[0051] Those skilled in the art will understand that the modules, or units, or components of the devices in the examples disclosed herein can be arranged in a device as described in the example, or alternatively can be located in one or more devices different from the device in the example. The modules in the foregoing examples can be combined as a module or further divided into multiple sub-modules.

[0052] Those skilled in the art will appreciate that the modules in the devices in the examples can be changed adaptively and disposed in one or more devices different from the example. The modules or units or components in the examples can be combined as a module or unit or component, and further divided into multiple sub-modules or sub-units or sub-components. All the features disclosed in this specification (including the claims, abstract and drawings) and all the processes or units of any methods or apparatuses so disclosed can be combined in any combination, except where such features or processes exclude each other. Each feature disclosed in this specification (including the claims, abstract and drawings) can also be replaced by an alternative feature providing the same, equivalent or similar functionality unless expressly stated otherwise.

[0053] Further, those skilled in the art will appreciate that the features of the different examples described herein mean within the scope of the application and form different examples, although some examples described herein include certain features and not others that are included in other examples. For example, in the following claims, any of the claimed examples can be used in any combination.

[0054] Further, some of the examples described herein are combinations of methods or method elements with the necessary instructions for implementing the methods or method elements. Thus, the processor with the necessary instructions for implementing the methods or method elements forms the means for implementing the methods or method elements. Further, the elements of the device examples described herein are examples of means for implementing the functions performed by the elements for the purpose of the application.

[0055] As used herein, unless otherwise specified, the use of the ordinal adjectives "first", "second", "third", etc., merely to distinguish different instances of an object to which the ordinal adjectives apply, and are not intended to denote a given sequence or order of such objects. Thus, a first object and a second object, for example, are both objects, merely with different reference labels.

[0056] While the application has been described in accordance with the various embodiments shown and described, it is to be understood that the application is not limited to those precise embodiments, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the present application. It is intended that the scope of the application should only be limited as recited in the appended claims.

Claims

1. A method for generating axial suspension repulsion, characterized in that, This is achieved through a magnetic levitation bearing device, which includes a thrust bearing, an excitation disk, and a conductor disk. The conductor disk is wound around the outside of the thrust bearing. The excitation disk and the conductor disk are interlocked and wound around a drive shaft. The excitation disk is a permanent magnet. A hollow coil and an iron-core coil are disposed within the conductor disk, and the hollow coil and the iron-core coil are cross-connected. The end face of the conductor disk and the interlocked portion of the excitation disk includes an excitation surface and a magnetically conductive surface. The other end face is provided with a main carrier and an interlocking slot for embedding the hollow coil and the iron-core coil, and for transmitting energy through the hollow coil and the iron-core coil. The interlocked portion of the excitation disk and the conductor disk is provided with an eddy current generator, an upper fixed plate for the generator, and an upper protective plate for the generator. The eddy current generator is internally composed of an iron core and an excitation coil. The other side of the excitation disk is provided with... The device has a radial ribbed cover plate and is fixed to the drive shaft by an axial limiter. When the excitation disk rotates with the drive shaft, it generates a rotating magnetic field that rotates along the drive shaft. Under the action of this rotating magnetic field, the hollow coil and iron core coil in the conductor disk cut magnetic field lines to generate an induced electromotive force, producing eddy currents in the coils. The induced magnetic field generated by the eddy currents is in the same direction as the magnetic poles of the permanent magnet in the excitation disk. The induced magnetic field and the permanent magnet magnetic field form a levitation magnetic chain, and the resulting levitation repulsive force is conducted out through the iron core of the iron core coil, outputting an axial levitation repulsive force that is opposite in direction and equal in magnitude to the axial load. The device also includes an axial limiter and a closed housing. The axial limiter is used to fix the axial position of the excitation disk and the conductor disk on the drive shaft, and the closed housing is used to cover the excitation disk and the conductor disk. The method includes: When the drive shaft rotates, the excitation disk rotates around the drive shaft to generate a rotating magnetic field; Under the action of the rotating magnetic field, superimposed induced electromotive forces are generated in the hollow coil and iron core coil in the conductor disk, and an induced magnetic field with the same direction as the magnetic pole of the permanent magnet is output. The induced magnetic field and the permanent magnet magnetic field form a levitation magnetic chain, generating a levitation repulsive force that is equal in magnitude and opposite in direction to the axial load. As the rotational speed of the drive shaft increases, the induced electromotive force superimposed in the conductor disk increases, and the magnitude of the suspension repulsion force increases with the increase of axial load and decreases with the decrease of axial load.

2. The method for generating axial suspension repulsion according to claim 1, characterized in that, When the rotational speed of the drive shaft is less than a preset threshold, the induced electromotive force generated by the hollow coil provides a levitation repulsive force against axial load. When the rotational speed of the drive shaft is greater than the preset threshold, the induced electromotive force superimposed by the hollow coil and the iron core coil jointly provides a levitation repulsive force against axial load.

3. The method for generating axial suspension repulsion according to claim 1, characterized in that, The core of the iron core coil is made of any one of the following soft magnetic materials: silicon steel sheet, permalloy, amorphous soft magnetic alloy, and nanocrystalline alloy. The excitation disk is made of any one of the following permanent magnet materials: neodymium iron boron, samarium cobalt, alnico, and ferrite.

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