Abstract: A friction clutch or friction brake is provided having a basic body and a friction body portion. The friction body portion can be mass-produced separately from the basic body, using a planar metal sheet-like material which is treated leading to a sintered powder friction facing. The friction clutch has a non-planar friction surface, operating in a box filled with oil as a lubricant. The friction body is applied to the basis body by form-locking friction, friction-gripping and/or material-locking techiques. In a preferred embodiment, the friction clutch or brake is a synchronizing ring and/or a correcting ring for motor vehicle shift gears.The friction clutch or friction brake according to the invention has particularly favorable friction properties, a long service life and low manufacturing costs. In a great number of applications, the shaping of separte draining grooves for expelling the oil when the friction grip is produced between matching components can be omitted.

Abstract: An apparatus and a method for the testing of synchronizing devices. In contrast to a conventional apparatus, in which only one rotating transmission gear or rather its synchronizing cone cooperates with a nonrotating synchronizing ring, it is now possible to test a complete synchronizing device consisting of two transmission gears, two synchronizing rings and one gear-shift sleeve with a hub. A transmission gear is fixedly connected to a rigid frame, the other transmission gear is connected to the drive through a drive shaft. The hub with the gear-shift sleeve is coupled with a flywheel mass on the driven side. The flywheel mass on the driven side is during a first shifting operation connected to the drive and is accelerated to the driving speed for testing. The flywheel mass now rotating at the driving speed is then again delayed until standstill through the synchronizing device during a second shifting operation.

Abstract: In lubricated friction couplings, at least two surfaces are connected by frictional engagement. These surfaces in engagement with one another are termed friction partners. One friction partner consists of a ceramic material and the other friction partner consists of a metallic material or a ceramic material having a chemical composition other than that of the first friction partner. The metallic material is a material of the iron group, preferably sintered metal. The ceramic material is oxide ceramic, especially aluminium oxide or zirconium oxide or silicon nitride. The pairing of metal, especially sintered steel, against oxide ceramic increases the service life of the coupling while at the same time reducing the coupling travel.The ceramic material can be connected to a carrier member, for example in the form of segments sintered into the carrier member.