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Magnetic bearing applied ‘ One)

31st July 2013 Bearing Technology 0 Comments

The magnetic bearing supports the load or suspends a kind of supporting form of the trochanter by magnetic force. This kind of bearing is developed quickly in recent years, especially in high speed, low friction drag, high low Warm and application under the vacuum environment. The magnetic bearing has its unique superiority compared with other supporting forms, there is a development prospect very much.

First, characteristic and classification


Friction is small, low power dissipation, can realize ultrafastly that operate.

It is high to support the precision, have steady operation, reliable.

Can operate under high temperature, deep freezing and vacuum environment.

The structure is complicated, require the condition to be harsh, there are magnetical influences on environment, but not polluted by others.


The magnetic bearing, according to classification such as its control mode, magnetic energy source, structural style. In addition, can also divide into permanent magnetical type, electric magnetical type and permanent magnnet – electro-magnet phenotype according to the magnetic field type. Can also divide into suction type and repulsion type according to the lift force type of the bearing. The superconductive magnetic bearing is still divided into two kinds low-temperature superconduction and high-temperature superconduction.

Exist still during the different kinds of various the above-mentioned classification some restrain from specially, should pay special attention to.

The permanent magnet type bearing can only be the passive inactive mode ,The passive bearing can not be steady in 3 directions, a direction should adopt active types at least.

The direct current encouraging bearing is active type taking the initiative type .

The purely electric magnetical type bearing can only be controlled bearing of degree of freedom 5, its volume, quality and power consumption are all greater.

Repulsion type magnetic bearing, because of the low utilization rate of the magnetic force, relatively the suction type is complicated in the structure, generally seldom adopt.

Typical magnetic bearing of two, several kinds

1.Magnetic bearing of permanent magnet type

The magnetic bearing of permanent magnet type is made of permanent magnnet, can make into various shapes. Bearing capacity and rigidity of the bearing are decided by the kind of permanent-magnet material, magnetic pole shape, area, thickness and Direction, bearing clearance, and the partial size of soft magnetic steel. The theoretical calculation of this kind of bearing is very difficult, often adopt ” similitude method of the experiment ” Carry on the constructional design. The instant using experimental method confirms several kinds of typical bearing structure, measure its bearing capacity, rigidity value. Designing the bearing newly so long as fetches the identical material, structural style and size are fixed in proportion, its characteristic can be found in proportion, such as bearing capacity is proportional to square of the bearing characteristic dimension etc..

The experience proves, increase the magnet thickness and adopt the pole piece structure of soft magnetic steel, it is valid to the bearing capacity which improves the bearing. The one that is worth paying special attention to is, forever no matter which kind of permanent-magnet material and any structural style to fetch the magnetic bearing, a maximum size is limited, once exceed this size, the bearing can’t support its autogenous weight. So, the magnetic bearing can’t be designed too big forever.

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