Adjustable magnetic buoyancy gravity compensator

Patent metadata

Field	Value
Publication number	US-10415639-B2
Application number	US-201615553724-A
Country	US
Kind code	B2
Filing date	Feb 24, 2016
Priority date	Feb 28, 2015
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A magnetic gravity compensator comprises a stator (1), a rotor (2), a base (4) and an adjustment mechanism (6). The stator (1) is disposed on the base (4), and the rotor (2) is levitated with respect to the stator (1). The stator (1) comprises a central cylindrical magnet (11) that is fixed to the base (4) by the adjustment mechanism (6) and consists of at least two arc magnets (111). The adjustment mechanism (6) has a first end fixed to the base (4) and a second end securely connected to the at least two arc magnets (111). The adjustment mechanism (6) is configured to drive the at least two arc magnets (111) to synchronously move radially with respect to a central axis of the central cylindrical magnet (11) so as to change a magnetic circuit between the central cylindrical magnet (11) and the rotor (2), and thereby adjust a magnetic levitation force between the stator (1) and the rotor (2).

First claim

What is claimed is:

1. A magnetic gravity compensator, comprising a stator, a rotor, a base and an adjustment mechanism, the stator disposed on the base, the rotor levitated with respect to the stator, wherein the stator comprises a central cylindrical magnet that is coupled to the base by the adjustment mechanism and consists of at least two arc magnets, the adjustment mechanism configured to drive the at least two arc magnets to synchronously move radially with respect to a central axis of the central cylindrical magnet so as to change a magnetic circuit between the central cylindrical magnet and the rotor, and thereby adjust a magnetic levitation force between the stator and the rotor;
wherein the adjustment mechanism comprises a driver, at least two followers connected to the driver and an adjuster, the driver connected to the base, the at least two followers in fixed connection with the at least two arc magnets, the adjuster configured to actuate the driver to adjust radial positions of the at least two followers and the at least two arc magnets with respect to the central axis of the central cylindrical magnet.

2. The magnetic gravity compensator according to claim 1 , wherein the rotor comprises an inner magnet ring and an outer magnet ring, wherein the stator further comprises a coil of a voice coil motor, and wherein the central cylindrical magnet, the inner magnet ring, the coil of the voice coil motor and the outer magnet ring are disposed concentrically, from innermost to outermost.

3. The magnetic gravity compensator according to claim 2 , wherein the inner magnet ring and the outer magnet ring are fixed by a rotor frame.

4. The magnetic gravity compensator according to claim 2 , wherein the coil of the voice coil motor is secured to the base by a coil frame.

5. The magnetic gravity compensator according to claim 1 , wherein a number of the at least two followers corresponds to a number of the at least two arc magnets.

6. The magnetic gravity compensator according to claim 1 , wherein the driver is a threaded disc with which the at least two followers are threadedly engaged, and wherein the adjuster is disposed on the base such that the threaded disc rotates with the adjuster, thereby causing the at least two followers and the at least two arc magnets to synchronously move radially with respect to the central axis of the central cylindrical magnet.

7. The magnetic gravity compensator according to claim 1 , wherein the driver is a frustum and the at least two followers are wedge-shaped blocks corresponding to the frustum, and wherein the adjuster is disposed on the base such that rotation of the adjuster causes the frustum to move vertically and causes the at least two followers and the at least two arc magnets to synchronously move radially with respect to the central axis of the central cylindrical magnet.

8. The magnetic gravity compensator according to claim 1 , wherein the driver is a cylindrical base with a central protrusion and the at least two followers are slide blocks connected to the driver by movable hinges, and wherein the adjuster comprises an adjusting nut and an screw rod engaged with the adjusting nut, the screw rod disposed inside the cylindrical base with ends thereof connected to the movable hinges and the base, respectively.

9. The magnetic gravity compensator according to claim 1 , wherein the central cylindrical magnet consists of six or eight arc magnets.

10. The magnetic gravity compensator according to claim 1 , wherein the central cylindrical magnet is magnetized along the central axis thereof.

11. The magnetic gravity compensator according to claim 2 , wherein each of the at least two arc magnets, the inner magnet ring and the outer magnet ring is made of NdFeB.

Assignees

• Shanghai Micro Electronics Equipment Group Co Ltd

Inventors

• Ji Hanchuan
• Chen Qingsheng

Classifications

• H02K33/18

  with coil systems moving upon intermittent or reversed energisation thereof by interaction with a fixed field system, e.g. permanent magnets · CPC title

• G03F7/70758 Primary

  Drive means, e.g. actuators, motors for long- or short-stroke modules or fine or coarse driving · CPC title

• H02K41/031

  of the permanent magnet type · CPC title

• F16C32/0603

  supported by a gas cushion, e.g. an air cushion · CPC title

• H02K1/27

  Rotor cores with permanent magnets · CPC title