DE10238543A1 - Passive electromagnetic radial bearing, e.g. for heavy flywheel storage device, has shell field structure, radial air gap, bearing function provided by magnetic binding of ferromagnetic ring body - Google Patents

Abstract

The device has a shell magnetic field structure, within which there is an almost field-free space, with a radial working air gap whose magnetic flux is otherwise completely in ferromagnetic material and whose radial bearing function is provided by the magnetic binding of a ferromagnetic ring body that reduces the magnetic resistance in the shell field circuit by its central position in the air gap.

Description

For heavy flywheel storage, swirl wheels for position control of satellites and for quick running processing machines where high interference forces have to be compensated passive magnetic bearings are not available.

(Note: As a passive magnetic bearing are generally only called magnetic bearings with permanent magnet technology. The invention now disclosed includes an electromagnetic one Bearing whose magnetizing current does not have to be readjusted, and can therefore also be called a passive camp.)

In my patent application dated December 29, 2001

(Title: "Finless jacket field homopolar machine with integrated magnetic bearing ") is a DC operated passive magnetic thrust bearing with a mantle field structure proposed. For the stable, Magnetic bearings of a rotating body in five degrees of freedom are additionally at least two magnetic radial bearings required. For relative Small magnetic bearing applications are already inherently stable, passive Radial bearings, which with the help of two fixed permanent magnetic, axially magnetized rings are produced.

Two stationary ring magnets of the same size are concentrically one above the other arranged and are in an axially attractive arrangement. in the There is an air gap between the ring magnets, a ring made of soft iron for rotation arranged. Information about reluctance bearings are easy to find on the Internet. With the jacket field toroid is the possibility given that on a small scale already proven Transpose reluctance bearing technology into the targeted range.

The mode of operation of permanent magnetic reluctance bearings can be mimicked electromagnetically with the help of cladding field coils be, which makes a relatively simple, maintenance-free and therefore inexpensive storage also for heavy rotating body possible appears. The radial rigidity of a ring bearing increases proportionally with the edge length of the bearing, with what a high interference forces greater Diameter is obviously advantageous. magnetopermanent Rings are only available with a relatively small diameter. The electromagnetic radial bearing proposed here enables diameters of a few meters.

function Description based on the schematic representation of the rotationally symmetrical Lasers cut through the plane of the axis of symmetry

Due to the inner shell winding ( 3 ) and the outer shell winding ( 4 ) flows for the magnetization of the cladding field core ( 1 ) required direct current. The current direction in the outer winding is opposite to the current direction in the inner. The number of current turns should be approximately the same inside and outside in order to ensure the highest possible electromagnetic compatibility.

The non-magnetic support body ( 7 ) prevents the poles from approaching each other at the working air gap and serves as a carrier for the inner winding.

A ferromagnetic ring (the same material as the outer field core) rotates in the center between the pole faces, which is prevented from axial displacement by an axial bearing (not shown) in the central plane between the pole faces. This ring is connected to the rotor axis via a disc (5) ( 6 ) connected. This arrangement resists a radial displacement from the magnetic equilibrium position, which is characterized in that, in the absence of an interference force, the rotating ring within the air gap assumes exactly the radial position at which the magnetic circle of the jacket field, in which the rotating ring is included , has the least magnetic resistance.

Additional comments:

Because of the quadratic dependence the radial stiffness from the air gap induction should (massive) Core material, one if possible high saturation magnetization exhibit.

With superconducting execution of the Shell windings become essential in comparison to the normally conductive version less winding volume required the shell geometry can be reduced overall and thus a drastic Weight saving can be achieved. Thanks to the high-temperature superconductors available today (HTSL) the direct current required for magnetization can Flow through the ring coils of the jacket field magnet without loss. The Solenoids can with liquid Nitrogen inexpensively chilled become. In space you only need the radiation energy of the sun shield to the required low temperature for superconductivity to ensure.

The arrangement with the cladding field structure found can also be reproduced with permanent magnets. Ideally, the core of the cladding field consists entirely of magnetically permanent magnetic material, or is with commercially available ring magnets and connecting egg parts reproduced. If medium diameters are required for which there are no ring magnets, smaller segments can also be put together like a parquet. This can be done on the pole faces themselves and / or on any other cross-sectional planes of the cladding field circle.

Claims (4)

Magnetic radial bearing with a cladding field structure (there is an almost field-free space within the cladding field), characterized in that the cladding field has a radial working air gap, the magnetic flux of which is otherwise completely in ferromagnetic material and the radial bearing function is given by the magnetic integration of a ferromagnetic ring body , which due to its central positioning in the air gap reduces the magnetic resistance in the cladding field circuit. (Short designation for this constellation mentioned under 1: jacket field radial bearing or (MF-RL) MF-RL, whose magnetic excitation by at least one internal and an outer shell winding is realized, the windings of which direct current flows in opposite directions become. Between inner and outer shell winding is the ferromagnetic core. They work in this core Coating pairs magnetizing in the same direction. Outside the core field core the magnetic fields compensate each other. MF-RL, the core of which is wholly or partially made of permanently magnetized Segments, which has a suitable direction of magnetization imprinted is. MF-RL, whose pole faces just like the magnetic ring body of the rotating body to be stored a lower one for the purpose of flow concentration in the air gap Cross section than the rest of the core material.