Abstract: An X-ray tube has a rotating anode and a plain bearing for mounting the rotating anode in a vacuum housing. The plain bearing has an inner bearing part that is stationary in relation to the vacuum housing, and a rotating outer bearing part that is connected with the rotating anode and that rotates with this anode relative to the vacuum housing during the operation of the X-ray tube. Between these inner and outer bearing parts there is a bearing gap filled with lubricant at least in the region provided for the transmission of force. The inner bearing part, which extends through the outer bearing part, is connected to the vacuum housing at both ends. The bearing gap has the same outer diameter at each of its two ends.

Abstract: A liquid metal plain bearing has a rotating and a stationary bearing part between which a bearing gap filled with liquid metal is located. The rotating bearing part has in relation at least one ring groove arranged to the bearing gap so that liquid metal possibly emerging from the bearing becomes located in the ring groove during the operation of the bearing and is held in the ring groove by the effect of centrifugal force.

Abstract: A plain bearing having a bearing gap filled with liquid metal has two plain bearing parts each having a surface contiguous to the liquid metal, these surfaces delimiting a gap connecting the bearing gap with the surrounding space. At least one of the surfaces is provided, in its area contiguous to the liquid metal, with a layer of a material that is effective as a wetting agent for the liquid metal.