Abstract: The invention relates to a disk storage device having a direct-driving motor for a hub, which has one or two plane air gaps, whereby information storage disks fixed to a hub and located in an operation chamber rotate so as to store data and whereby optical and/or magnetic write/read heads are provided for reading or writing the data on the information carrier disks, whereby the hub of the information carrier disks and the write/read heads are supported together with their driving units on a device chassis or on a device cover plate and whereby the motor driving the hub is a collectorless DC motor having the permanent magnets at the part of the rotor and an ironless disk winding adjacent to the air gap or air gaps, whereby the soft magnetic yoke parts are provided with collar-like stiffening projections (FIG. 1).

Abstract: A position sensor using a soft magnetic core and a permanent magnet for detecting linear or rotary movements of a part. In one embodiment, a differential transformer is provided with corresponding windings 3, 4 and 5, which are wound on a tubular carrier member 2. Provided inside the carrier member 2 are a saturatable core 6 with a V-shaped crosssection section and a control magnet 8 which slides on the inner surfaces. The core 6 is partially saturated on the contact surfaces, so that a virtual air gap is produced, so that the transformation ratio between the windings 3 and 4, 5 is controlled as a function of position. Other versions employ flat and/or meandering coil arrangements and, in two instances, rotational relative motion.