Rotary-anode x-ray tube comprising a helical-groove sleeve bearing and

Abstract

The invention relates to a rotary-anode X-ray tube comprising a sleeve bearing, notably a helical-groove bearing, for journalling the rotary anode in the axial direction, which bearing comprises at least two pairs of bearing surfaces for taking up axial forces acting in opposite directions, each pair comprising two bearing surfaces which are present on bearing portions which are rotatable with respect to one another and which bearing surfaces cooperate via a lubricant, the helical-groove bearing communicating with the vacuum space of the X-ray tube via at least opening. Because at the area between the pairs of bearing surfaces there is provided a lubricant reservoir which communicates with the lubricant in the pairs of bearing surfaces and in the stationary bearing portion there is provided a duct which connects the lubricant reservoir to the vacuum space of the X-ray tube, it is achieved that the bearing will not be damaged in the case of loss of lubricant.