CN108757731A - A kind of radial-axial Three Degree Of Freedom magnetic bearing of permanent magnet axial magnetized - Google Patents

Abstract

A radial and axial three-degree-of-freedom magnetic bearing with permanent magnets magnetized axially, comprising a stator and a rotor. The radial control core on the radial outer side of the radial part of the core, and the two axial control cores arranged symmetrically on both sides of the radial control core. air gap, radial suspension windings are wound on the radial control core; permanent magnets are respectively connected between the outer edges of the two axial control cores and the radial control core, and two A suction disk, a control disk is concentrically arranged between the two suction disks, and an axial suspension winding is wound on each of the two suction disks.

Description

A radial and axial three-degree-of-freedom magnetic bearing with axial magnetization of permanent magnets

technical field

The invention relates to the field of three-degree-of-freedom magnetic bearings, in particular to a radial and axial three-degree-of-freedom magnetic bearing with axial magnetization of permanent magnets.

Background technique

Compared with the mechanical bearings used in traditional motors, magnetic bearings can effectively solve the vibration, wear, Friction, need for lubrication, etc. The unique design principle of the magnetic bearing makes it have high application value and broad application prospects in the fields of high speed, high precision and vacuum.

Patent Publication No. CN201410156526, a patent document named a three-degree-of-freedom magnetic bearing and patent publication No. CN201410461449, a three-degree-of-freedom hybrid magnetic bearing proposed in a patent document named a new axial-radial three-degree-of-freedom hybrid magnetic bearing , the stator is composed of axial and radial iron cores, and the rotor is always in a state of free movement in the axial direction. The principle of minimum is to select the stator axial core magnetic circuit on the side with the reduced axial air gap instead of the magnetic circuit on the side with the increased axial air gap. As we all know, for the same air gap size, due to high performance The use of permanent magnet materials leads to a large air gap magnetic field strength generated by the permanent magnet, which can reach 0.8T or higher, while the air gap magnetic field strength generated by the winding electrification is small, about 0.2T~0.3T, and the suspension controls the magnetic flux When adjusting the bias flux, one side decreases from 0.8T to 0.5T, while the other side increases from 0T to 0.3T, the force direction of the rotor does not change, which leads to the axial failure to start.

Patent Publication No. CN201110232913, named as a radial-axial three-degree-of-freedom AC-DC hybrid magnetic bearing, adopts double permanent magnets to provide axial and radial bias magnetic flux structure, although it solves the problem of axial start-up difficulty, but The two permanent magnets in its structure occupy the inner space of the bearing, so that the winding occupies a small space, the axial and radial magnetic pole areas are reduced, and the axial and radial levitation forces generated are reduced; in addition, because the thickness of the magnetic isolation material must be Determined according to the thickness of the air gap, the use of multiple magnetic isolation rings results in a complex structure, high manufacturing process requirements, and high prices.

Contents of the invention

The purpose of the present invention is to address the shortcomings of the existing three-degree-of-freedom magnetic bearings, to provide a magnetic bearing with small volume, simple manufacturing process, compact structure, no coupling between axial suspension force and radial suspension force, and axial offset on both sides of the radial part of the rotor. Radial and axial three-degree-of-freedom magnetic bearings with axial magnetization of permanent magnets whose magnetic flux is always equal.

The present invention is realized through the following technical solutions:

A radial and axial three-degree-of-freedom magnetic bearing with permanent magnets magnetized axially, comprising a stator and a rotor. The radial control core on the radial outside of the radial part of the core, and the two axial control cores symmetrically arranged on both sides of the radial control core, and a radial working core is arranged between the radial control core and the radial part of the rotor core. air gap, radial suspension windings are wound on the radial control core; permanent magnets are respectively connected between the outer edges of the two axial control cores and the radial control core, and two A suction disk, a control disk is concentrically arranged between the two suction disks, and an axial suspension winding is wound on each of the two suction disks.

A further solution of the present invention is that the length of the air gap between the control disc and the radial part of the rotor core is greater than the length of the air gap between the suction disc and the radial part of the rotor core.

A further solution of the present invention is that the permanent magnet is an axially magnetized annular permanent magnet.

A further solution of the present invention is that the permanent magnet is made of rare earth permanent magnet material or ferrite permanent magnet material.

The advantage of the present invention compared with prior art is:

1. Two axially magnetized permanent magnets provide axial and radial bias fluxes respectively. When the axial bias flux is shifted in the axial direction of the rotor, it can still ensure the left and right sides of the radial part of the rotor. The lateral axial bias magnetomotive force is always equal, which solves the problem of difficult axial start of the magnetic bearing; the inner edge of the axial control core facing the radial part of the rotor core adopts a " The E" shape structure ensures the smooth path of the axially controlled levitation flux, and realizes the stable levitation of the rotor in the axial direction through the interaction between the axial levitation winding and the axial bias flux;

2. There is no coupling problem between the radial suspension force and the axial suspension force, which reduces the difficulty of control, is conducive to the application in high-speed occasions, and is easy to realize industrially;

3. Compared with the prior art that uses two axially magnetized permanent magnets to provide static bias magnetic flux, the two axially magnetized permanent magnets used in the present invention are embedded in the radial control core without occupying The internal space of the bearing increases the space for radial and axial control windings, which can increase the axial and radial suspension force;

4. The "E" shape structure adopted by the axial control core provides a closed path for the axial suspension control flux, which is the condition that the axial bias magnetomotive force on the left and right sides of the rotor shaft is always equal.

Description of drawings

Fig. 1 is a structural sectional view of the present invention.

Detailed ways

A radial and axial three-degree-of-freedom magnetic bearing with permanent magnets axially magnetized as shown in Figure 1 includes a stator and a rotor, and the rotor is composed of a rotating shaft 16, a radial portion 14 of the rotor core and an axial portion 15 of the rotor core .

The stator includes a radial control core 3 arranged at intervals on the radially outer side of the radial part 14 of the rotor core to form a radial working air gap, and left axial control cores 1 and 1 symmetrically arranged on both sides of the radial control core 3 . The side axial control core 5 ; the radial suspension winding 26 is wound on the radial control core 3 .

Between the outer edges of the left axial control core 1 and the right axial control core 5 and the radial control core 3, there are ring-shaped left permanent magnets 2 and right permanent magnets 4 respectively. The magnet 2 and the permanent magnet 4 on the right are axially magnetized annular permanent magnets made of rare earth permanent magnet materials or ferrite permanent magnet materials, which provide bias magnetic flux to the radial and axial three degrees of freedom respectively; the left Two left suction discs 6 and two right suction discs 7 are concentrically arranged on the inner walls of the side axial control core 1 and the right axial control core 5 respectively, and the gap between the two left suction discs 6 and A left control disc 8 and a right control disc 9 are arranged concentrically between the two right suction discs 7 respectively. The air gap between the left control disc 8 and the right control disc 9 and the radial part 14 of the rotor core The length is greater than the air gap length between the left suction disk 6, the right suction disk 7 and the radial part 14 of the rotor core, and the two left suction disks 6 and the two right suction disks 7 are respectively wound with left Axial suspension winding 10, right axial suspension winding 12; two left suction disks 6, left control disk 8 and left axial core 1, and two right suction disks 7, right control disk 9 and right The lateral axial iron cores 5 form an "E"-shaped structure respectively.

The radial part 14 of the rotor core, the axial part (15) of the rotor core, the left axial core 1, the right axial core 5, and the radial control core 3 are all made of materials with good axial and radial magnetic permeability, Both the left axial suspension winding 10 and the right axial suspension winding 12 are formed by winding electromagnetic coils with good electrical conductivity and drying them with varnish.

The left axial core 1, the left axial suspension winding 10, the radial control core 3, the radial suspension winding 26, the right axial core 5, the right axial suspension winding 12, the left permanent magnet 2, the right The permanent magnets 4 are stacked axially.

The levitation principle is: the left permanent magnet 2 and the right permanent magnet 4 generate two parts, the left bias magnetic flux 20 and the right bias magnetic flux 25 respectively; Starting from the pole, the two left suction disks 6 are divided into two parts: the left inner bias magnetic flux 19 and the left outer bias magnetic flux 27, and then pass between the two left suction disks 6 and the radial part 14 of the rotor core. The left axial air gap, the rotor core radial part 14, the radial working air gap, the radial control core 3, return to the S pole of the left permanent magnet 2 to form a left closed magnetic circuit.

The right bias magnetic flux 25 starts from the N pole of the right permanent magnet 4, and is divided into two parts, the right inner bias magnetic flux 23 and the right outer bias magnetic flux 24, through two right suction discs 7, and then passes through two parts respectively. The right side axial air gap between the right suction disk 7 and the radial part 14 of the rotor core, the radial part 14 of the rotor core, the radial working air gap, the radial control core 3, and the right side permanent magnet 4 The S pole forms a right closed magnetic circuit.

The radial suspension winding 26 is energized to generate a radial suspension magnetic flux 28, and the radial suspension magnetic flux 28 passes through the upper side of the radial control core 3, the upper radial air gap, the radial part 14 of the rotor core, the axial part 15 of the rotor core, The radial air gap on the lower side and the lower side of the radial control core 3 form a closed path; it is used to change the strength of the air gap magnetic field on both sides of the magnetic bearing rotor core in the radial direction. According to the prior art, a radial displacement sensor is installed on the stator to establish The radial displacement closed-loop control system keeps the air gap between the stator and the rotor even in the radial direction, and realizes the stable suspension of the rotor in the radial direction; two sets of left axial suspension windings 10 and two sets of right axial suspension windings 12 are energized to generate four axial suspensions respectively The magnetic fluxes are respectively: left inner axial suspension magnetic flux 17, left outer axial suspension magnetic flux 18, right inner axial suspension magnetic flux 21, right outer axial suspension magnetic flux 22, and the four axial suspension magnetic fluxes are commonly used to change The strength of the magnetic field in the air gap on both sides of the rotor core in the magnetic bearing axis is established by installing an axial displacement sensor on the stator to establish an axial displacement closed-loop control system to keep the air gap between the stator and rotor axially uniform and to achieve stable suspension of the rotor in the axial direction .

Claims (4)

1. a kind of radial-axial Three Degree Of Freedom magnetic bearing of permanent magnet axial magnetized, including stator and rotor, the rotor is by turning Axis（16）, rotor core radial part（14）With rotor core axial part（15）Composition, it is characterised in that：The stator includes interval It is set to rotor core radial component（14）The radial control iron core in outside（3）, and it is symmetrically disposed on radial control iron core（3） The axial control iron core of two of both sides, the radial control iron core（3）With rotor core radial component（14）Between be provided with diameter To working gas gap, the radial control iron core（3）On be wound with radial suspension winding（26）；Described two axial control iron cores Outer and radial control iron core（3）Between be connected separately with permanent magnet, along being arranged concentrically twice suction disk respectively in inner wall, Control disk has been arranged concentrically between the twice suction disk, be respectively wound on the twice suction disk axial suspension around Group.

2. a kind of radial-axial Three Degree Of Freedom magnetic bearing of permanent magnet axial magnetized as described in claim 1, it is characterised in that： The control disk and rotor core radial component（14）Between gas length be more than suction disk and rotor core radial part Point（14）Between gas length.

3. a kind of radial-axial Three Degree Of Freedom magnetic bearing of permanent magnet axial magnetized as described in claim 1, it is characterised in that： The permanent magnet is the annular permanent magnet of axial charging.

4. a kind of radial-axial Three Degree Of Freedom magnetic bearing of permanent magnet axial magnetized as described in claim 1 or 3, feature exist In：The permanent magnet is made of rare earth permanent-magnetic material or iron oxygen permanent-magnet material.