CN108591750B

CN108591750B - Large-sized precise magnetic suspension rotary worktable

Info

Publication number: CN108591750B
Application number: CN201810440921.8A
Authority: CN
Inventors: 任长志; 叶宇; 乐中宇; 徐进; 张夏杰
Original assignee: Nanjing Institute of Astronomical Optics and Technology NIAOT of CAS
Current assignee: Nanjing Institute of Astronomical Optics and Technology NIAOT of CAS
Priority date: 2018-05-10
Filing date: 2018-05-10
Publication date: 2020-11-10
Anticipated expiration: 2038-05-10
Also published as: CN108591750A

Abstract

The large precise magnetic suspension direct-drive rotary worktable comprises a driving motor of the rotary worktable, an angular displacement feedback system, a radial active bias magnetic suspension bearing, an axial protection bearing and a radial protection bearing, wherein the active bias magnetic suspension bearing is provided with the rotary worktable and restrains the axial movement and the radial movement of the rotary worktable, the protection bearing, a braking device and a position feedback system are also provided, and a signal of the position feedback system is output to a control system to control the driving motor and the braking device. The invention eliminates the friction of the mechanical bearing, is easy to process, assemble and transport, and has low maintenance cost. The device has the advantages of high rotation precision, strong bearing capacity, low power consumption and no crawling during ultra-low speed operation, and can be widely applied to the fields of astronomical observation instruments, numerical control machines, radars, precise turntables and the like.

Description

Large-sized precise magnetic suspension rotary worktable

Technical Field

The invention relates to a magnetic suspension direct-drive rotating device, in particular to a large-scale precise magnetic suspension direct-drive rotating workbench which can be used for an azimuth axis of an astronomical telescope, a precise measurement and control simulation rotating platform and the like.

Background

The large astronomical telescope tracking frame, the spacecraft simulation test platform, the precision machine tool rotary table and the like (hereinafter referred to as a rotary workbench) are high-precision equipment, and are required to have small friction torque, high rigidity of a transmission mechanism, quick dynamic response and high rotation precision. At present, a rotating workbench is generally supported by a hydrostatic bearing and a mechanical bearing, the hydrostatic bearing is very complex in structural design and has very high requirements on machining and manufacturing precision, and the diameter of the hydrostatic bearing required by a large rotating workbench, such as a 30-meter astronomical telescope azimuth axis, can reach 50 meters, which is undoubtedly a very serious challenge. In addition, the performance of the hydraulic oil is greatly influenced by temperature, the oil temperature and the ambient temperature need to be strictly controlled, a reliable oil supply system and an independent standby power supply system are needed, the occupied space is large, the maintenance cost is high, the control system is complex, and the problem is more obvious for a large astronomical instrument with ultra-low-speed precise tracking. The active magnetic suspension supporting technology has the advantages of non-contact, no friction, high precision, low power consumption, low mechanical assembly requirement and the like, and can be integrated with a driving motor, so that the structure is simplified, and the cost is reduced. The direct drive technology can save a speed reduction device in the application occasions of low speed and large torque, so that the design has the advantages of compact structure, high reliability, excellent acceleration performance and the like, and is widely applied to various precision equipment.

Disclosure of Invention

The invention aims to provide a large precise magnetic suspension direct-drive rotating workbench which has a wide application range compared with the prior art. The rotary worktable provided by the invention has the advantages of strong bearing capacity, no friction, low power consumption, high transmission efficiency, high rotation positioning precision, wide speed regulation range and no crawling during ultra-low speed running. Meanwhile, magnetic suspension support and direct drive of the rotary workbench are realized, and the technology has wide application prospect in application occasions such as large astronomical telescopes and spacecraft measurement and control platforms with extremely high requirements on reliability, precision, bearing and the like.

The technical scheme for completing the invention task is as follows: the utility model provides a large-scale accurate magnetic suspension directly drives swivel work head, including swivel work head's driving motor, angle displacement feedback system, radial active bias magnetic suspension bearing, axial protection bearing and radial protection bearing, the device has the swivel work head rotatory around the rotation center and retrains this swivel work head axial motion and radial motion's active bias magnetic suspension bearing to the design has corresponding protection bearing, arresting gear and position feedback system, and control system is given to this position feedback system's signal output, and control system controls driving motor and arresting gear's work, its characterized in that: the rotary worktable is supported in a magnetic suspension manner by an active bias magnetic suspension bearing, is provided with a protection bearing for protection, and directly drives the rotary worktable through a permanent magnet synchronous torque motor.

The driving part of the rotary worktable is realized by a permanent magnet synchronous torque motor. The stator of the energizable base part of the permanent-magnet synchronous torque motor is rigidly connected to the base, the rotor part of the motor is designed as a permanently excited armature which is rigidly connected to the rotary table via a connecting part, and the device for detecting the angle and/or phase position is advantageously arranged axially and/or radially between the armature.

Aiming at a large-diameter permanent magnet synchronous torque motor, according to an optimized scheme, the permanent magnet synchronous torque motor adopts a splicing type and unit type structural design, and each independent winding is assembled into a complete stator unit through a positioning structure by a minimum stator winding unit. The silicon steel sheet is insulated from the coil by an insulating isolation cover.

The permanent magnet synchronous torque motor is a three-phase permanent magnet torque motor, adopts a radial magnetic field structure, and is designed into 2L (L =1, 2, 3, 4 … …) minimum unit motors, wherein the 2L minimum units can be flexibly and freely combined into P unit motors with larger power, the P unit motors share one rotor, and according to the size of the model, P =1, 2, 3, 4, … …. The P independent unit motors can independently or cooperatively drive the rotary table.

The stator of the permanent magnet synchronous torque motor adopts a unit structure design, and each independent and complete stator unit is formed by combining a plurality of minimum stator winding units; m (M =1, 2, 3, 4, … …) stator units are uniformly distributed on the same circumference, and each independent stator unit can be independently operated as a motor and also can be operated in a synergic or redundant mode. The stator core of each winding unit is formed by punching a 0.3mm silicon steel sheet through a progressive die at one time.

The motor rotor of the permanent magnet synchronous torque motor is formed by alternately and uniformly sticking N N poles and N S poles (N =1, 2, 3 and …) on a rotor shaft. The permanent magnet adopts a radial magnetizing mode; each magnetic pole is composed of m (m =1, 2, 3, …) permanent magnets with equal length and same polarity; the m permanent magnets with equal length and same polarity are uniformly bonded on the motor rotor shaft by an automatic gluing assembly mechanism along the circumferential direction in an N, S-pole alternating mode; a stainless steel protective cover is designed outside the permanent magnet of each magnetic pole to prevent the permanent magnet from falling off.

The designed permanent magnet synchronous torque motor is also provided with a cooling system, a cooling medium circulation channel is arranged on a motor stator shell, sealing grooves are arranged on two sides of the motor stator shell, O-shaped rubber sealing rings are embedded in the sealing grooves, and a cooling shell is matched on the outer side of the motor stator shell and is fixedly connected with the motor stator shell and an equipment base through bolts; two cooling joint threaded holes are processed on the cooling shell, the inlet cooling joint and the outlet cooling joint are respectively connected with the cooling joint threaded holes, during cooling, the cooling medium input pipe is connected with the inlet cooling joint, and the output pipe is connected with the outlet cooling joint.

In order to restrict the radial degree of freedom and protect the rotary worktable when the magnetic suspension bearings fail, at least one set of radial magnetic suspension bearings and one set of radial protection bearings are required, wherein the radial protection bearings are preferably rolling bearings, ball bearings or roller bearings which can be used as protection bearings. In all cases, in order to achieve frictionless suspension of the rotary table, the balls or rollers protecting the rolling bearings are kept at the same distance from a cylindrical surface on the rotary table of the central rotary member and smaller than the air gap of the radial magnetic bearing, confining the rotary table within the effective space of movement. The radial active magnetic suspension bearing is a non-mechanical contact bearing. The radial active bias magnetic suspension bearing is in a unitized design, is distributed on the circumference of the rotary worktable in pairs, and has the logarithm w (w =1, 2, 3, 4, … …), and the typical structure is 2. In order to effectively and accurately control the radial active magnetic suspension bearing to ensure the rotation precision of the rotary worktable of the central rotating part, 2 the position of the rotary center of the rotary worktable is measured in real time by uniformly distributed radial bearing position sensors, and the radial active magnetic suspension bearing is controlled in real time according to the detected deviation to ensure that the rotary central shaft of the rotary worktable is in a specified precision space.

Similarly, in order to restrict the axial degree of freedom and protect the rotary table when the magnetic suspension bearings fail, at least one set of axial magnetic suspension bearings and one set of axial protection bearings are required to be arranged, in order to realize frictionless suspension of the rotary table, the axial protection bearings do not contact the rotary table when in operation, only when the axial magnetic suspension bearings fail or are impacted by a large load, the axial protection bearings have a protection function, and the axial magnetic suspension bearings and other parts of the device are protected from being damaged. The axial protective bearing is preferably a rolling bearing, a ball bearing or a roller bearing. In all cases, in order to achieve frictionless suspension of the rotary table, the balls or rollers of the axial protection bearings are kept at the same distance from the only axial bearing surface of the rotary table of the central rotary member, which is smaller than the air gap of the axial magnetic suspension bearings, thus limiting the axial movement of the rotary table within the effective movement space. The axial magnetic suspension bearing is a non-mechanical contact bearing and can be a permanent magnet biased, electromagnetic controlled active magnetic suspension bearing or a mixed bearing combining the permanent magnet biased and the electromagnetic controlled active magnetic suspension bearing. According to an optimized design scheme, the axial offset magnetic suspension bearings are in a unitized design, are distributed on the circumference of the rotary worktable in pairs, and have the logarithm r (r =1, 2, 3, 4, … …), and the typical structure is 2. Similarly, the axially active controllable magnetic suspension bearings are also of unitized design, and are distributed on the circumference of the rotary worktable in pairs, and the axially active controllable magnetic suspension bearings are distributed on the same circumference in a manner of being orthogonal to the positions of the offset magnetic suspension bearings, the logarithm of the axially active controllable magnetic suspension bearings is t (t =1, 2, 3, 4 and … …), and the typical structure of the axially active controllable magnetic suspension bearings is 2. 2, the position deviation of the rotary worktable is measured in real time by the uniformly distributed axial magnetic bearing position sensors, the axial active controllable magnetic suspension bearing is controlled in real time, the axial position of the rotary worktable is ensured, and the high-precision capacitive sensor is preferentially selected by the axial active magnetic suspension bearing position sensor.

The angular displacement sensor is used for realizing precise position control and speed control of the rotary worktable. The rotary worktable of the central rotating part can be arranged on the inner cylindrical surface and can also be arranged on the outer cylindrical surface. The angular displacement sensor can be an incremental sensor or an absolute sensor. According to a preferred embodiment, the angular displacement sensor is an incremental sensor, which is fixed in a designed groove of the rotary table of the central rotary part by means of an adhesive connecting medium. Alternatively, to construct a redundant system and improve the reliability of the system, the angular displacement sensor is equipped with p (p =1, 2, 4, 8) signal reading devices. The angular displacement signal is processed by the controller and is used for controlling the position and the speed of the rotary worktable.

In order to realize emergency braking of the large rotary worktable, at least one set of brake is required to be arranged, and the brake is preferably an electromagnetic brake, a hydraulic brake or a pneumatic brake which can be used as the brake of the rotary worktable. According to the optimized design scheme, preferably, the electromagnetic brakes are arranged, z (z =1, 2, 3, 4 and … …) electromagnetic brakes are symmetrically and uniformly arranged on the circumference of the base, the brake plane of each brake keeps the same distance with the unique brake plane on the rotary worktable, and when power is lost, the brake plane of each brake is in contact with the unique brake plane on the rotary worktable to realize the braking of the rotary worktable.

According to the integrated optimization design, a bearing plane, a braking plane, a circular grating mounting groove, a protection bearing supporting surface, a magnetic suspension bearing rotor and the like are effectively integrated and designed on one component by the designed central cylinder rotary worktable; in a more effective form, the axial offset magnetic suspension bearing unit and the axial active magnetic suspension bearing unit share the same rotor plane (magnetic conduction structure), and the rotor plane is simultaneously used as a braking plane of the braking device. Furthermore, the radial offset magnetic suspension bearing unit and the radial active magnetic suspension bearing unit share the same rotor cylinder (magnetic conduction structure), and the rotor cylinder can be used as a support cylindrical surface of a radial protection bearing.

The invention has the advantages that the active bias magnetic suspension bearing technology and the direct drive technology are combined, the friction of a mechanical bearing is eliminated, and the integrated large-scale precise magnetic suspension direct drive rotary worktable is easy to process, assemble, transport and maintain and has low maintenance cost. The rotary worktable has the advantages of high rotation precision, strong bearing capacity, low power consumption and no crawling during ultra-low speed operation.

Drawings

FIG. 1 is an overall cross-sectional view of a large self-bearing direct drive magnetic levitation rotary table;

FIG. 2 is an axial partial sectional view of a large self-bearing directly driven magnetic levitation rotary table;

FIG. 3 is an overall sectional view of a direct drive motor;

FIG. 4 is an overall cross-sectional view of an axial active magnetic suspension bearing;

FIG. 5 is a cross-sectional view of the brake;

FIG. 6 is an overall cross-sectional view of the radial protection bearing;

FIG. 7 is an overall view of the radial protection bearing;

FIG. 8 is a structural diagram of an axial active magnetic suspension bearing;

FIG. 9 is a view of the structure of an axially offset magnetic bearing;

FIGS. 10-1, 10-2, and 10-3 are schematic diagrams of the structure of a direct drive motor;

FIG. 11 is a schematic diagram of a radial active magnetic suspension bearing mechanism;

FIG. 12 is a schematic diagram of the structure of an axial protection bearing and a radial offset magnetic suspension bearing;

FIG. 13 is a view showing a structure of a part of the rotary table.

Detailed Description

In embodiment 1, a large-scale precise magnetic suspension direct-drive rotating table is mainly composed of a base 1, a permanent magnet synchronous torque motor 6, a radial active magnetic suspension bearing 7, a radial offset magnetic suspension bearing 8, a radial protection bearing 9, a rotating table 5, an axial active magnetic suspension bearing 2, an axial offset magnetic suspension bearing 4, an axial protection bearing 12, an angular displacement sensor 10, a sensor seal cover 11, a motor seal cover 13 and an electromagnetic brake 3, as shown in fig. 1-6. The device is horizontally placed, a load is installed on a rotary worktable 5, initialization is firstly carried out during working, an axial active type magnetic suspension bearing 2 is initialized, control current is initialized and the axial position is controlled according to the position calibrated by an axial active type magnetic suspension bearing position sensor, meanwhile, a radial active type magnetic suspension bearing 7 is initialized, and control current is initialized and the rotary center position of the rotary worktable is controlled according to the position calibrated by a radial active type magnetic suspension bearing position sensor. When the rotary worktable 5 needs to rotate or rotate a certain angle, the controller controls the permanent magnet synchronous torque motor 6 to execute a system command. The axial active magnetic suspension bearing 2 and the radial active magnetic suspension bearing 7 respectively control the rotation center and the axial position of the rotary worktable 5 in real time through respective controllers by utilizing feedback information of an axial active magnetic suspension bearing position sensor and a radial active magnetic suspension bearing position sensor.

The driving of the rotary worktable 5 is realized by a permanent magnet synchronous torque motor 6 (see fig. 9), the permanent magnet synchronous torque motor 6 is a three-phase permanent magnet synchronous torque motor, a radial magnetic field adopts a unit type and splicing type design structure, and the main stator shell 601, an O-shaped sealing ring 602, a cooling medium input interface 606, a cooling medium output interface 603, a cooling sealing shell 604, a cooling medium flow channel 605, a motor sealing cover plate 616, a phase-finding sensor 617 and 619, a rotor magnetic ring 612, a permanent magnet 613, a permanent magnet protective cover 614, a magnetic air gap 615, epoxy resin 611, a stator winding 609, a stator core 608 and a stator core fixing key 610.

The permanent magnet synchronous torque motor is provided with M (M =1, 2, 3, 4, … …) independent stator units which are uniformly distributed on the same circumference (see figure 2), and each independent stator unit (motor) 6 can be independently used as a motor to operate and also can be operated synchronously or redundantly. In this embodiment there are 4 stator units 6, sharing a single rotor, which can independently or cooperatively drive the rotary table 5.

Aiming at a large-scale precise rotary workbench in an implementation example, the permanent magnet synchronous torque motor 6 adopts a 9-slot/8-pole splicing type unit structure design. As an example of this patent, but not limited thereto, each winding stator core unit 608 is stamped from 1000 sheets of 0.3mm silicon steel, and the tooth slots of each internal unit are of a structure for reducing the cogging; and the outermost winding unit of each complete stator unit adopts an optimized design for reducing the end effect. Stator core 608 is insulated from stator winding 609 by an insulating cage.

The optimized design for reducing the end effect is shown in fig. 10, specifically, a favorable magnetic line loop structure is designed on the two outermost stator cores 608 of the stator unit.

The permanent magnet synchronous torque motor 6 realizes the phase searching of the motor through a phase searching sensor 617-619 to determine the phase, wherein the phase searching sensor is an HALL sensor.

The motor rotor consists of p N poles and p S poles (p =1, 2, 3, …); each magnetic pole 613 is composed of m (m =1, 2, 3, …) permanent magnets with equal length and same polarity, and the permanent magnets adopt a radial magnetizing mode; the m permanent magnets with equal length and same polarity are uniformly bonded on the motor rotor shaft by an automatic gluing assembly mechanism in an N, S-pole alternating mode; the protection device is designed outside the permanent magnet to strengthen the adhesion strength of the permanent magnet.

More specifically, as a specific implementation example, the motor rotor is formed by bonding 512N poles and 512S poles alternately and uniformly on the rotor shaft 612; the whole rotor consists of 64 rotor units, 8N-pole permanent magnet magnetic poles and 8S-pole permanent magnet magnetic poles are alternately and uniformly distributed on each rotor unit, and each permanent magnet magnetic pole 613 consists of 3 permanent magnets with equal length and same polarity and adopting a design for reducing the cogging; the 3 permanent magnets with equal length and same polarity are uniformly distributed and bonded on the motor rotor shaft 612 by an automatic gluing assembly mechanism in an N, S-pole alternating mode; to prevent damage due to the falling-off of the permanent magnet, a stainless steel protective cover 614 is mounted on the outside of the permanent magnet pole 613 and fixed to the motor rotor shaft 612 by screws.

According to an optimized scheme, the designed direct-drive torque motor is designed with a cooling system, wherein the cooling system consists of O rows of sealing rubber rings 602, a cooling medium input interface 606, a cooling medium output interface 603, a cooling shell 604, a cooling medium and a cooling medium circulating channel 605: the motor stator housing 601 is provided with a cooling medium circulation channel 605, two sides of the cooling medium circulation channel 605 are provided with sealing grooves, an O-shaped rubber sealing ring 602 is embedded in each sealing groove, the cooling housing 605 is matched with the outer side of the sealing groove, and the cooling housing is connected and fixed with the motor stator housing 601 and the equipment base 1 through bolts. During cooling, the cooling medium flows into the cooling medium circulation passage 605 through the input port 606, and the heated cooling medium flows back to the cooling system through the output port 603.

The rotary worktable 5 adopts an integrated optimization design, and a bearing plane 502, a braking plane 501, a circular grating mounting groove 504, protective

bearing supporting surfaces

503 and 505 and magnetic suspension bearing rotors (magnetic conduction structures) 501 and 503 are effectively designed on one component. Specifically, the component mainly comprises a brake plane, wherein the axial active bias

magnetic suspension bearings

2 and 4 share one structural component 501, the radial active bias

magnetic suspension bearings

7 and 8 share one rotor cylinder (magnetic conduction structure) 503, and the axial protection bearings share the same rotor cylinder (magnetic conduction structure).

The axial active type magnetic suspension bearing mainly comprises an axial bias magnetic suspension bearing unit 4 and an axial active type magnetic suspension bearing unit 2, and is a non-mechanical contact bearing. The magnetic suspension bearing can be a permanent magnet biased active magnetic suspension bearing or a hybrid bearing combining the permanent magnet biased active magnetic suspension bearing and the electromagnetic active magnetic suspension bearing, and a hybrid magnetic suspension bearing structure is selected as an implementation example, in the implementation example, 4 axial biased magnetic

suspension bearing units

4 and 4 axial active magnetic suspension bearing units 2 share one axial rotor. The 4 axial offset magnetic suspension bearing units 4 and the 4 axial active magnetic suspension bearing units 2 are alternately and uniformly arranged on the same circumference. The axial active magnetic suspension bearing unit 2 and the axial rotor 5 form an axial main control controllable magnetic suspension bearing, and the axial position of the rotary worktable 5 is controlled by the controller in real time according to the feedback information of the axial active bias magnetic suspension bearing position sensor.

In the axial active bias magnetic bearing described in fig. 8, the axial active magnetic suspension bearing unit 2 is mainly composed of a stator core 206, an outer magnetic conductive ring 202, an inner magnetic conductive ring (rotor) 202, an exciting coil 203, epoxy resin 209, a magnetic air gap 202, and an axial active magnetic suspension bearing position sensor 207, four axial active magnetic suspension bearing units 2 are uniformly distributed on the same circumference, and each unit is fixed on the base 1 by 36 bolts. The axial bias magnetic suspension bearing unit 4 is mainly installed on a base 401, magnetic conductive rings 402, permanent magnets 403, magnetic air gaps 404, rotor magnetic conductive rings 405, a positioning key slot 406 and locking screws 407, four axial bias magnetic suspension bearing units 4 and the axial active magnetic suspension bearing unit 2 are uniformly distributed on the same circumference in a rotating staggered mode at 45 degrees, and similarly, each unit is fixed on the base 1 through 36 bolts. The 4 axial magnetic bearing position sensors which are distributed in an orthogonal mode send detection signals to the axial permanent magnet bias active magnetic bearing by measuring axial displacement signals in 2 orthogonal directions in the z direction of the rotary worktable 5, and after the detection signals are converted into control quantity, the rotary worktable 5 of the central rotating part of the shaft is controlled in real time.

As shown in fig. 11, the axial auxiliary bearing 12 is mainly used to protect the entire rotary table from being damaged when the rotary table 5 is impacted by a large external load or the axial active bias magnetic suspension bearing fails. The designed axial auxiliary bearing 12 mainly comprises a bearing mounting base 1201, a large ball 1202, a small ball 1203, a bearing end cover 1204, a base 1, a rotating table 5 bearing supporting groove 1205 and a gap 1207. According to the preferred mode, 36 sets of auxiliary protective bearing units 12 are uniformly distributed on the same circumference, the number of the design is not limited to 36, and the auxiliary protective bearing units can be freely combined according to the size and the bearing capacity of the device. A spherical groove 505 matched with the large ball 1202 is designed on the rotary workbench 5, and the distance between each axial auxiliary bearing unit and the spherical groove 505 on the workbench 5 is consistent by adjusting the bearing mounting base 1201. Then, the base is fixed on the designed installation plane of the base 1 through a locking nut.

In a further optimized mode, a pressure sensor is further designed on the bearing mounting base 1201, whether the rotary table 5 is in contact with the axial auxiliary bearing 12 or not and whether an overload problem exists or not can be detected, and the working state of the rotary table 5 is monitored according to the detection value of the pressure sensor.

The radial active magnetic suspension bearing (shown in figure 11) is a non-mechanical contact bearing, can be a permanent magnet biased bearing, can also be an active magnetic suspension bearing or the combination of the permanent magnet biased bearing and the active magnetic suspension bearing, and the device of the invention adopts 4 active control

magnetic bearing units

7 and 4 permanent magnet biased magnetic bearing units 8 to share one rotor (the rotary worktable 5 is designed to be equivalent to a magnetic suspension rotor rotary cylinder). The 4 radial active control magnetic bearing units 7 are uniformly distributed and installed on the same circumference. The active control magnetic bearing unit 7 controls the rotating center position of the rotating workbench in real time by a controller of the radial active control magnetic bearing unit 7 through a space vector analysis control algorithm according to the feedback information of the radial active magnetic bearing position sensor.

As shown in fig. 11, the radial active magnetic suspension bearing 7 mainly comprises an outer magnetic conductive ring 701, a stator core 702, an excitation coil 704, epoxy 703, a magnetic air gap 705, a rotor magnetic conductive ring, a sensor, and the like, and the four radial active control magnetic bearing units 7 are uniformly distributed on the motor stator mounting base 1. The rotary worktable 5 is provided with a rotor magnetic conduction ring. 4 radial active magnetic suspension bearing position sensors which are distributed in an orthogonal mode are installed on the end cover, detection signals are sent to a controller of the radial active magnetic suspension bearing through measuring displacement signals in 5 x and y 2 orthogonal directions of the main rotating table, and after the detection signals are converted into control quantity, the rotating center of the rotating table 5 is controlled in real time.

As shown in fig. 7, the radial auxiliary bearing 9 is mainly used for protecting the entire rotary table from being damaged when the rotary table 5 is impacted by a large external load or the axial active bias magnetic suspension bearing fails. The designed axial auxiliary bearing 9 mainly comprises a bearing mounting base 901, a bearing roller 902, a cylindrical roller bearing 906, an upper bearing end cover 905, a bolt 904, a lower bearing end cover 907, a bolt 906 and a bearing cylindrical surface of the rotary workbench 5. According to the preferred mode, 8 sets of auxiliary protection bearing units are uniformly distributed on the same circumference, the number of the design is not limited to 8, and the auxiliary protection bearing units can be freely combined according to the size and the bearing capacity of the device. The rotary table 5 is designed with a cylindrical support surface for supporting the axial auxiliary bearing 9, and the distance between each axial auxiliary bearing unit and the bearing support surface on the table 10 is made to be consistent by adjusting the support base 901.

Claims

1. The utility model provides a large-scale accurate magnetic suspension directly drives swivel work head, including swivel work head's driving motor, angle displacement feedback system, radial active bias magnetic suspension bearing, axial protection bearing and radial protection bearing, this swivel work head has the swivel work head rotatory around the rotation center and retrains this swivel work head axial motion and radial movement's active bias magnetic suspension bearing to the design has corresponding protection bearing, arresting gear and position feedback system, and control system is given to this position feedback system's signal output, and control system controls driving motor and arresting gear's work, its characterized in that: the rotary worktable is supported in a magnetic suspension manner by an active bias magnetic suspension bearing, is provided with a protection bearing for protection, and directly drives the rotary worktable through a permanent magnet synchronous torque motor;

the permanent magnet synchronous torque motor adopts a splicing type and unit type structure design, each independent winding is assembled into a complete stator unit by a minimum stator winding unit through a positioning structure, and the tooth grooves of the internal units adopt a structure for reducing the tooth groove effect; the outermost winding unit of each complete stator unit adopts an optimized design for reducing the end face effect, and the silicon steel sheet is insulated from the coil through an insulating isolation cover;

the permanent magnet synchronous torque motor is a three-phase permanent magnet torque motor, adopts a radial magnetic field structure and is designed into 2L minimum unit motors, wherein L =1, 2, 3, 4 … … and 2L minimum units are freely combined into P unit motors with larger power, the P unit motors share one rotor, and the P independent unit motors independently or cooperatively drive a rotary workbench according to the size of the model, P =1, 2, 3, 4 … …;

the stator of the permanent magnet synchronous torque motor adopts a unit structure design, and each independent and complete stator unit is formed by combining a plurality of minimum stator winding units; the M stator units are uniformly distributed on the same circumference, wherein M =1, 2, 3, 4 … …, and each independent stator unit independently operates as a motor or operates in a synergic or redundant mode; the stator iron core of each winding unit is formed by punching a 0.3mm silicon steel sheet through a progressive die at one time, and the silicon steel sheets of the two stator windings on the left and right outermost sides of the stator unit are provided with favorable closed loop structures of magnetic force lines;

the number of poles of the permanent magnet synchronous torque motor 6 is 1024, the permanent magnet synchronous torque motor is composed of 4 stator units and 64 rotor units, and the permanent magnet synchronous torque motor drives the rotary worktable independently or cooperatively; each stator unit is provided with a respective independent phase searching sensor, and the used phase searching sensor adopts a Hall sensor;

the motor rotor of the permanent magnet synchronous torque motor is formed by alternately and uniformly sticking N N poles and N S poles on a rotor shaft; n =1, 2, 3 … …, and the permanent magnet adopts a radial magnetizing mode; each magnetic pole consists of m permanent magnets with equal length and same polarity, wherein m =1, 2, 3 … …, and the m permanent magnets with equal length and same polarity are uniformly bonded on the motor rotor shaft by an automatic gluing assembly mechanism along the circumferential direction in a mode of N, S poles in an alternating mode; a stainless steel protective cover is designed outside the permanent magnet of each magnetic pole to prevent the permanent magnet from falling off;

the permanent magnet synchronous torque motor is a three-phase permanent magnet torque motor, adopts a 9-slot/8-pole design, and has a radial magnetic field distribution; each independent unit motor independently operates as a motor, or operates redundantly or synchronously;

the permanent magnet synchronous torque motor is also provided with a cooling system: a cooling medium circulation channel is arranged on the motor stator shell, sealing grooves are formed in two sides of the motor stator shell, an O-shaped rubber sealing ring is embedded in each sealing groove, and the cooling shell is matched with the outer side of the sealing groove and is fixedly connected with the motor stator shell and the equipment base through bolts; two cooling joint threaded holes are processed on the cooling shell, the inlet cooling joint and the outlet cooling joint are respectively connected with the cooling joint threaded holes, during cooling, the cooling medium input pipe is connected with the inlet cooling joint, and the output pipe is connected with the outlet cooling joint.

2. The large-scale precise magnetic suspension direct-drive rotating workbench according to claim 1, wherein the whole rotor of the permanent magnet synchronous torque motor consists of 64 rotor units, each rotor unit is alternately and uniformly distributed with 8N-pole and 8S-pole permanent magnets, each magnetic pole consists of 3 permanent magnets with equal length and same polarity, and the design of reducing the cogging effect is adopted; the 3 permanent magnets with equal length and same polarity are uniformly assembled on the motor rotor shaft by an automatic gluing assembly mechanism in an N, S-pole alternating mode; and a stainless steel protective cover is arranged outside the permanent magnet and is fixed on the connecting part of the motor rotor through screws.

3. The large-scale precise magnetic suspension direct-drive rotary worktable as claimed in claim 1 or 2, wherein the radial active magnetic suspension bearing and the axial active magnetic suspension bearing are non-mechanical contact magnetic suspension bearings, or electrically excited magnetic suspension bearings, or permanent magnet bias control active magnetic suspension bearings, or electromagnetic control active magnetic suspension bearings, or permanent magnet passive magnetic suspension bearings; l radial active magnetic suspension bearings are uniformly distributed on the same circumference, L =1, 2 … …, the radial permanent magnet biased magnetic suspension bearing is responsible for bearing the turntable, the radial active magnetic suspension bearing is responsible for dynamic compensation, P axial active magnetic suspension bearings are uniformly distributed on the same circumference, P =1, 2 … …, the radial permanent magnet biased magnetic suspension bearing is responsible for bearing the turntable, the radial active magnetic suspension bearing is responsible for dynamic compensation, and the whole magnetic suspension bearing supporting system operates cooperatively.