CN2597738Y - Hybrid Magnetic Bearing - Google Patents

Abstract

The hybrid magnetic suspension bearing belongs to the mechanical field and consists of three parts: a high temperature superconducting magnetic suspension bearing, an active magnetic suspension bearing and a permanent magnetic suspension bearing. The high temperature superconducting magnetic suspension bearing is installed at the bottom, and the axial permanent magnetic suspension bearing is installed on the top. Two radial active magnetic suspension bearings are installed inside the permanent magnetic magnetic suspension bearing and the high temperature superconductive magnetic suspension bearing. The radial active magnetic suspension bearing improves the The radial stiffness and damping of the superconducting magnetic suspension bearing can overcome the resonance generated at the critical speed of the rotor, reduce mechanical vibration and loss, and ensure the high-speed and stable rotation of the system. The utility model can solve the problems of low bearing capacity, low stiffness, small damping, uncertain working position, field cooling and zero-field cooling existing in the current high-temperature superconducting magnetic suspension bearing, and is beneficial to the development of magnetic suspension bearing technology and high-temperature superconducting block material engineering The application has great theoretical research significance and practical application value.

Description

Hybrid Magnetic Bearing

technical field

The utility model relates to a hybrid magnetic suspension bearing, which belongs to the field of machinery.

Background technique

Magnetic suspension bearing is a new type of high-performance bearing that uses magnetic field force to suspend the rotor in the air, so that there is no mechanical contact between the rotor and the stator. Magnetic suspension bearings have no mechanical friction, can reduce energy consumption and noise, have the advantages of no need for lubrication, no oil pollution, long life, and can be applied to many application environments, so they have advantages that cannot be compared with general traditional bearings and support technologies.

There are three types of existing magnetic suspension bearings: permanent magnet, superconducting, and active. According to the different ways of generating magnetic levitation force, the magnetic levitation bearing composed of permanent magnets is called permanent magnetic levitation bearing, and the bearing that generates magnetic levitation by superconductor is called superconducting magnetic levitation bearing. The magnetic levitation bearing generated by electromagnetic attraction is called active magnetic levitation bearing.

The permanent magnet magnetic levitation bearing has the advantages of simplicity, reliability and low price, but the suspension system composed entirely of permanent magnetic materials has the problems of damping and instability. Similarly, the traditional active magnetic suspension bearing using electromagnetic attraction is itself an unstable system, which must be controlled by a fast-response feedback system. The high-temperature superconducting magnetic suspension bearing made of high-temperature superconductor is itself a stable system without active control. However, the superconducting magnetic suspension bearing using high-temperature superconductors has problems such as flux creep, low load-carrying capacity, low stiffness, small damping, and uncertain working positions.

Contents of the invention

In order to overcome the shortcomings of the above-mentioned prior art, the utility model proposes a vertical high-temperature superconducting active permanent magnet hybrid magnetic suspension bearing, which is composed of a high-temperature superconducting magnetic suspension bearing, an active magnetic suspension bearing and a permanent magnetic suspension bearing. The high temperature superconducting magnetic suspension bearing is installed at the bottom, and the top is equipped with an axial permanent magnetic suspension bearing. Determine and field cooling and zero-field cooling problems; at the same time, the utility model installs two radial active magnetic suspension bearings inside the permanent magnetic magnetic suspension bearing and the high temperature superconducting magnetic suspension bearing, and the radial active magnetic suspension bearing improves the performance of the superconducting magnetic suspension bearing. The radial stiffness and damping overcome the resonance generated at the critical speed of the rotor, reduce mechanical vibration and loss, and ensure the stable rotation of the system at high speed. Therefore, the utility model can solve the problems of low bearing capacity, low stiffness, small damping, uncertain working position, field cooling and zero field cooling existing in the current high temperature superconducting magnetic suspension bearing.

The rotor of the permanent magnet magnetic suspension bearing of the utility model is fixed on the rotating shaft of the magnetic suspension bearing through interference fit, and the stator thereof is fixed on the outer cover of the magnetic suspension bearing through the stator bushing. The permanent magnetic levitation bearing adopts the upper and lower permanent magnet rings with opposite radial magnetization directions, and the cross-sectional area of each permanent magnet ring is equal. The magnetic induction strength and magnetic pressure of the air gap generate greater interaction force between the two permanent magnetic rings, thereby improving the bearing capacity and rigidity of the permanent magnetic levitation bearing, and also solving the problem of magnetic shielding.

Description of drawings:

Fig. 1 is the mechanical structure drawing of the present utility model: 1, wiring socket; 2, end cap; 3, upper end axial sensor; 4, end cap; 5, protective bearing; 6, upper end radial sensor probe; 7, permanent magnet Magnetic levitation bearing stator; 8. Permanent magnetic levitation bearing rotor; 9. Permanent magnetic levitation bearing stator bushing; 10. Magnetic levitation bearing jacket; 11. Active magnetic levitation bearing rotor at the upper end; 12. Active magnetic levitation bearing stator at the upper end; Active magnetic suspension bearing stator bushing; 14. Rotating shaft; 15. Motor stator; 16. Motor rotor; 17. Active magnetic suspension bearing rotor at the lower end; 18. Active magnetic suspension bearing stator at the lower end; 19. Active magnetic suspension bearing stator bushing at the lower end ;20, the lower end radial sensor probe; 21, the lower end cover; 22, the support plate; 23, the coupling; 24, the support cylinder; 25, the high temperature superconducting magnetic suspension bearing rotor--flywheel; Superconducting block material yttrium barium copper oxide (YBCO)]; 27, liquid nitrogen; 28, liquid nitrogen container; 29, base; 30, adjusting bolt.

Fig. 2 is the structural sectional view of the permanent magnetic levitation bearing of the present utility model: 7, the permanent magnetic levitation bearing stator; 8, the permanent magnetic levitation bearing rotor; 31, the permanent magnetic ring; 32, the permanent magnetic ring; 33, the iron yoke.

Fig. 3 is a single-degree-of-freedom structural block diagram of the active magnetic suspension bearing of the present invention.

Fig. 4 is the structural diagram of the high temperature superconducting magnetic suspension bearing rotor of the present invention - the flywheel: 25, the high temperature superconducting magnetic suspension bearing rotor - the flywheel; 34, the cylindrical permanent magnet; 35, the annular permanent magnet.

Fig. 5 is a layout diagram of the superconducting blocks of the stator of the high temperature superconducting magnetic suspension bearing of the present invention.

Fig. 6 is a schematic block diagram of the HTS hybrid magnetic suspension bearing system of the present invention.

Mechanical structure of the present utility model as shown in Figure 1:

The upper permanent magnetic bearings 7, 8, 9, motors 15, 16, and active magnetic bearing stators 12, 18, rotors 11, 17 are respectively fixed on the magnetic bearing cover 10 and the rotating shaft 14 through interference fit. The displacement sensor probes 6, 20 and the protective bearing 5 are respectively fixed on the upper and lower end covers 4 and 21. The rotating shaft 14 is connected with the flywheel 25 through an interference fit through a coupling 23 to ensure the concentricity of the rotating shaft. The superconducting magnetic bearing stator 26 is housed in a liquid nitrogen container 28 . The whole device is fixed on the base 29 through the support plate 22 and the support cylinder 24 . In addition, the utility model can adjust the levelness of the device system through the supporting cylinder 24 and the adjusting bolt 30 .

Because the high temperature superconducting hybrid magnetic suspension bearing of the utility model adopts three kinds of magnetic suspension bearings, its rotor includes the rotors of these three kinds of bearings. As shown in Figure 1, the rotating shaft and the parts assembled on the rotating shaft are collectively called the rotor, and from top to bottom are: permanent magnetic magnetic suspension bearing rotor 8, upper end radial magnetic suspension bearing rotor 11, motor rotor 16, lower end radial magnetic suspension bearing Rotor 17, shaft coupling 23, high temperature superconducting magnetic suspension bearing rotor 25.

Fig. 2 is a structural sectional view of the permanent magnet magnetic suspension bearing of the present invention. Both the rotor 8 and the stator 7 of the permanent magnet magnetic levitation bearing adopt upper and lower permanent magnet rings 31 and 32 with different radial magnetization directions, and the cross-sectional area of each permanent magnet ring is equal. In order to reduce flux leakage and improve the utilization efficiency of permanent magnet materials, in addition to the air gap of the permanent magnet rings interacting with each other, the inner and outer rings of the permanent magnets all use iron yokes 33 for magnetic conduction and shielding, which reduces flux leakage and permanent magnets The magnetic induction intensity at the ring air gap is improved, and the magnetic force is proportional to the square of the magnetic induction intensity, so the suspension force and stiffness performance of the permanent magnetic suspension bearing can be greatly improved.

Fig. 3 is a single-degree-of-freedom structural block diagram of the active magnetic suspension bearing of the present invention. It is mainly composed of active magnetic suspension bearing stators 12, 18, rotors 11, 17, sensors, controllers and power amplifiers. In the active magnetic suspension bearing system, each active magnetic suspension bearing stator 12, 18 is composed of four electromagnets, and the four electromagnets are arranged symmetrically along the circumference of the rotor 11, 17, so that a pair of symmetrical Electromagnets, which can control two radial degrees of freedom. As shown in Figure 3, the displacement signal is detected by the sensor, and a pair of symmetrical power amplifier circuits drive the electromagnet in a differential mode, so that the rotor is subjected to two electromagnetic forces in opposite directions on one degree of freedom at the same time.

Fig. 4 shows the structure of the high temperature superconducting magnetic suspension bearing rotor-flywheel 25. The rotor—the flywheel 25 includes a centrally located cylindrical permanent magnet 34 and an annular permanent magnet 35 . In order to increase the magnetic field strength gradient of the permanent magnet structure, the magnetization directions of the cylinder and the ring are opposite, one direction is upward and the other is downward.

Fig. 5 shows the layout of the superconducting blocks of the stator of the high-temperature superconducting magnetic suspension bearing. The utility model adopts seven yttrium barium copper oxides (YBCO) prepared by melting texture method with the same size. One of them is placed in the center, and the other six pieces surround the center. The blocks are evenly arranged on the circumference and aligned with the central circle of the permanent magnet ring.

Since the high-temperature superconductor in the superconducting state has strong diamagnetism and magnetic flux pinning, the high-temperature superconducting magnetic suspension bearing itself is a stable system. It is not only an axial magnetic suspension bearing, but also a radial magnetic suspension bearing, which can realize the rotor stable suspension and operation. In order to improve the carrying capacity of the superconducting magnetic suspension bearing, an axial permanent magnetic suspension bearing 7, 8, and 9 is placed on the top of the utility model for axial unloading so as to suspend the rotor with a larger mass. The radial stiffness and damping of the bearing are small. Two radial active magnetic suspension bearings 11, 12, 13, 17, 18, and 19 are installed in the middle of the utility model to control the dynamic state of the rotor when it transitions from static stable floating to stable operation. The radial swing generated during the process improves the radial stiffness and damping, thereby realizing the high-speed operation of the rotor. Protective bearings 5 are installed at both ends of the rotor for system debugging and for protection when the system runs out of control at high speed. Three-phase asynchronous intermediate frequency motors 15 and 16 are installed in the middle of the system device to drive the rotor to rotate at high speed. A flywheel 25 with embedded cylindrical permanent magnet 35 and annular permanent magnet 36 is installed at the bottom of the rotor, which together with the stator at the lower end—seven high-temperature superconducting blocks of yttrium barium copper oxide (YBCO) 26 form a high-temperature superconducting magnetic levitation bearings.

The active magnetic suspension bearing control system is mainly composed of active magnetic suspension bearing stators 12, 18, rotors 11, 17, sensors, controllers and power amplifiers. It uses two upper and lower radial active magnetic suspension bearings 11, 12, 13, 17, 18, and 19, and uses displacement sensors 6, 20 to detect the displacement deviation signal of the rotor. , adjust the excitation current of the radial electromagnet to adjust the electromagnetic attraction to the rotor, so that the rotor is controlled at the position of the axis, so as to realize the control of the radial movement of the rotor.

The structure schematic diagram of the whole HTS hybrid magnetic suspension bearing system is shown in Fig. 6, in which the dotted line part in the figure is the HTS hybrid magnetic suspension bearing. The whole high temperature superconducting hybrid magnetic bearing system includes permanent magnetic bearing, active magnetic bearing, high temperature superconducting magnetic bearing rotor - flywheel 25, high temperature superconducting magnetic bearing stator 26, liquid nitrogen container 28, displacement sensor, controller and power Amplifier, three-phase asynchronous motor and variable frequency power supply.

The working principle and process of the hybrid magnetic suspension bearing are described in detail below in conjunction with Fig. 6:

Permanent magnet magnetic levitation bearings rely on the interaction force between permanent magnets to generate levitation and do not require active control. Therefore, the utility model adopts axial permanent magnet magnetic suspension bearing to provide axially stable levitation force, so it can be used to unload axially, levitate the rotor, and determine the axial position of the rotor in advance. For vertical systems, the system is always in axial suspension. In order to improve the bearing capacity and rigidity of the permanent magnetic suspension bearing, the rotor 8 and the stator 7 of the permanent magnetic suspension bearing all adopt upper and lower permanent magnetic rings 31, 32 with different radial magnetization directions, and each permanent magnetic ring The cross-sectional area is equal. In order to reduce flux leakage and improve the utilization efficiency of permanent magnet materials, except for the gaps between the interacting permanent magnet rings, the inner and outer rings of the permanent magnets all use iron yokes 33 for magnetic conduction.

The working process of the utility model high-temperature superconducting active permanent magnet hybrid magnetic suspension bearing is as follows: firstly, inject liquid nitrogen from the liquid nitrogen Dewar container to the liquid nitrogen container, after the high-temperature superconducting block material yttrium-barium-copper-oxygen (YBCO) is cooled, That is, in the superconducting state, it has diamagnetism and flux pinning. High-temperature superconducting magnetic suspension bearings use the diamagnetism of superconducting blocks to provide a static magnetic suspension force, and use pinning to provide a stable force to achieve stable suspension. Therefore, it is both an axial magnetic suspension bearing and a radial magnetic suspension bearing. However, the magnetic levitation force of the high-temperature superconducting magnetic levitation bearing is related to the initial state and historical process of the external magnetic field before cooling. It has hysteresis characteristics, the working position is uncertain, and there are problems of field cooling and zero field cooling. The zero-field cold condition can provide greater magnetic levitation force, but the stiffness is not as good as the field cold condition. The utility model adopts the axial permanent magnetic levitation bearing, utilizes the permanent magnet to provide greater magnetic levitation force, the axial position is determined, and can adjust the high temperature superconducting magnetic levitation bearing rotor - flywheel 25 and The working clearance distance of the stator 26. The smaller the working gap is, the closer the embedded cylindrical permanent magnet 34 and the annular permanent magnet 35 at the bottom of the rotor-flywheel 25 are to the high-temperature superconducting block, the higher the background magnetic field of the high-temperature superconducting block is. The superconducting block is cooled in the magnetic field, that is, the high-temperature superconducting magnetic levitation shaft works in the field cooling mode, thus solving the problems of low carrying capacity, uncertain working position, zero-field cooling and field cooling of the high-temperature superconducting magnetic levitation bearing.

The hybrid magnetic levitation bearing system composed of high temperature superconducting magnetic levitation bearing and axial permanent magnetic levitation bearing can rotate smoothly at low speed. However, when the rotor accelerates from low frequency to high frequency, there is a critical speed problem. The radial stiffness and damping are small, and it is difficult to smoothly cross the critical speed. In order to smoothly cross the critical speed, as shown in Figure 1, between the motors 15, 16 installed in the middle of the rotating shaft 14 of the present invention and the upper end axial permanent magnetic levitation bearings 7, 8, and between the motor and the lower end high temperature superconducting magnetic levitation bearing 25 , 26, respectively install a radial active magnetic bearing 11, 12, 13 and 17, 18, 19, respectively control two radial degrees of freedom at the upper end of the rotor, and two radial degrees of freedom at the lower end, a total of four In this way, the radial swing generated when the rotor transitions from static stable floating to stable operation can be controlled, the radial stiffness and damping can be improved, and the high-speed operation of the rotor can be realized.

Detailed ways

Fig. 1 is a structural diagram of a specific embodiment. As shown in Figure 1, the high temperature superconducting magnetic suspension bearings 25,26 of the present embodiment are installed at the bottom, the axial permanent magnetic suspension bearings 7,8,9 are installed on the top, and the motors 15,16 and the upper end are installed in the middle of the rotating shaft 14 A radial active magnetic suspension bearing 11, 12, 13 and 17, 18, 19 is respectively installed between the axial permanent magnetic suspension bearings 7 and 8, and between the motor and the lower HTS magnetic suspension bearings 25 and 26. Both the rotor 8 and the stator 7 of the permanent magnet magnetic suspension bearing adopt upper and lower permanent magnet rings 31 and 32 with different radial magnetization directions, and the cross-sectional area of each permanent magnet ring is equal. In order to reduce flux leakage and improve the utilization efficiency of permanent magnet materials, except for the gaps between the interacting permanent magnet rings, the inner and outer rings of the permanent magnets all use iron yokes 33 for magnetic conduction.

The superconducting magnetic levitation bearing of this embodiment adopts seven pieces of yttrium barium copper oxide (YBCO) blocks with a diameter of φ30×18 mm, and the maximum magnetic buoyancy density can reach 14.4 N/cm ² . The performance indicators are: the mass of the rotor is about 3.5kg, the radial stiffness is about 1.68MN/m, the axial stiffness is about 65N/mm, and the operating speed is 9,600rpm. High temperature superconducting magnetic suspension bearings have low stiffness, about 10N/mm. In order to improve the stiffness of the superconducting magnetic suspension bearing, this embodiment adopts the radial active magnetic suspension bearing, and the radial stiffness reaches 1.68MN/m, which improves the radial stiffness of the superconducting magnetic suspension bearing by two orders of magnitude; in addition, the axial permanent The magnetic magnetic suspension bearing not only unloads axially, but also increases the axial stiffness of the high temperature superconducting magnetic suspension bearing by more than six times, reaching 65N/mm. Wide range of stability.

The utility model has great theoretical research significance and practical application value for the development of magnetic suspension bearing technology and the engineering application of high-temperature superconducting blocks.

Claims (2)

1, a kind of hybrid magnetic suspension bearing, it is characterized in that constituting by permanent magnetism magnetic suspension bearing, active magnetic bearing and super-conductive magnetic suspension bearing, a hts magnetic levitation bearing is installed in the bottom, an axial permanent magnetic magnetic suspension bearing is equipped with at the top, and two radially active magnetic bearings have been installed between permanent magnetism magnetic suspension bearing and hts magnetic levitation bearing.

2, according to the described hybrid magnetic suspension bearing of claim 1, it is characterized in that following two section area equate in the employing of permanent magnetism magnetic suspension bearing rotor and stator, the permanent-magnetic clamp that the diametrical magnetization direction is different, the permanent magnetism inner and outer rings adopts iron yoke magnetic conduction and shielding.

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