Design of Permanent Magnet Bearings with high stiffness

The stiffness of permanent magnet bearings, PMB’s, composed of only two magnet rings is limited, and it is well known that increasing the size of these magnets by increasing their cross section area has a very limited effect on bearing performance. Instead, in order to gain enough stiffness, axially stacked structures of comparatively smaller permanent magnets are frequently being used. By arranging the magnets with alternating polarity, the flux derivatives as well as the bearing stiffness are known to be increased.