Abstract: The invention relates to a planet gear having a planet carrier rotatable around an axis of rotation, comprising at least one planet wheel arranged on the planet carrier, a sun wheel and a ring gear, wherein the planet wheel is arranged in a movable manner at least radially with respect to the axis of rotation of the planet carrier. To minimize the backlash of a planet gear of this type, it is further provided that the ring gear is formed in two pieces on a plane perpendicular to the axis of rotation of the planet carrier, wherein the two halves of the ring gears can be rotated against each other and thereby effect a radial shift of the planet wheel in the direction towards the sun wheel in order to reduce backlash.

Abstract: A multistage spur-type gearing for small and miniature electric motors having a gearing housing and at least two gear shafts or axles held in the gearing housing, with spur gears of different diameters arranged on the gear shafts or axles. To achieve an extremely small construction at maximum reduction ratios in comparison with conventional spur-type gearings, at least two spur gears are fixedly connected to one another and combined to form a dual gear set, with the dual gear set rotatably supported on a gear axle made from a hard material, such as ceramics. At least one of the gear shafts should fixedly be held as a gear axle in the housing. An input shaft opening through which a motor shaft projects into the gearings is arranged to be substantially coaxial to the center axis of the gearing housing with which the gear shafts also extend in parallel and at some distance. Such a gearing makes it possible to arrange several reduction stages on one gear axle. Preferably, only two gear shafts or axles are used.

Abstract: Methods for fabricating a friction bearing, in particular for ceramic shafts, made of metallic hardenable sintered material having an open pore volume of at least 15%, wherein the sintered material is brought into a predetermined shape and is subsequently sintered. For improving the known friction bearings in that a local wear and tear of shaft and bearing is avoided or at least considerably reduced in the region of mixed friction with high lateral forces, it is provided to harden the friction bearing after the sintering.