Abstract: In rotary anodes which are journalled on two sides a problem occurs, notably as regards the bearing which is arranged on the side of the anode disc which is remote from the rotor. The problem involves excessive discharge of heat via the shaft and the bearing. A possibility of reducing the quantity of heat applied to the bearing consists in the increasing of the length of the anode shaft to increase the heat resistance. However, the length of the X-ray tube is then also increased. The invention provides a combination of smaller length, substantially free choice of the material of the anode shaft and hence overcritical speeds for the tube during operation by forming the anode shaft as a hollow rotor shaft coupled to the anode disc and a further shaft journalled at both ends to the respective bearings and connected to the hollow shaft.

Abstract: X-ray tubes with a magnetic bearing either have the disadvantage that the anode must be at earth potential, so that an asymmetric high-voltage supply is required or that -- in the case of a symmetric high voltage -- a relatively wide air gap is necessary which requires a high driving force and a bearing which has a certain amount of drawbacks. The invention provides an insulator between the anode which is at the high-voltage potential and the rotor which is at the earth potential, so that the air-gap between the rotor and stator can be relatively small and an effective magnetic bearing is possible.

Abstract: A rotary anode X-ray tube wherein the anode carries the high voltage during operation; to achieve shorter acceleration times of the rotor, an insulator is provided between the rotor and the anode disc so that only a minimum air gap is required between the rotor and the stator.