US Patent 8109040 Linear drive arrangement for a sliding door

A linear drive arrangement for a sliding door includes a guide track, a stator arrangement which is fixed with respect to the guide track, a guide carriage to which a door leaf can be fixed for movement parallel to the guide track, and a plurality of permanent magnets fixed to the carriage so that the carriage can be suspended by magnetic forces between the stator and the magnets. A pair of supporting rollers support the carriage on the guide track when the carriage is not fully suspended by the magnetic forces, particularly at the beginning and end of movement of the carriage.