Rotary anode X-ray tube
AssigneeU.S. Philips Corporation
InventorsJan Gerkema, Evert M. H. Kamerbeek
Life of this patent
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Abstract
An X-ray tube having a rotary anode which is supported by a bearing system comprising an axial magnetic bearing and at least one radial sleeve bearing. In operation, mutually cooperating metal (e.g. W or Mo) supporting faces of the sleeve bearing are separated by a liquid layer wetting the supporting faces. The liquid layer consists of a metal or a metal alloy, such as Ga or a Ga alloy, whose vapor pressure at 300.degree. C. is below 10.sup.-5 N/m.sup.2, and which does not attack the supporting faces to any substantial extent. The tube has a long life, produces little noise during operation, and is of relatively simple construction.
Claims10
An X-ray tube comprising:
- an envelope;
- a rotary anode in the envelope, said anode being rotatable around an axis and being axially and radially supported on the axis by a bearing system;
- a motor stator outside the envelope;
- and
- a motor rotor attached to the rotary anode for rotating the rotary anode on the axis in cooperation with the motor stator;
- characterized in that the bearing system comprises:
- a magnetic bearing for supporting the rotary anode axially;
- and
- at least one sleeve bearing for supporting the rotary anode radially, said sleeve bearing comprising cooperating metal supporting faces separated by a liquid layer of a metal or metal alloy which wets the supporting faces without substantially attacking the supporting faces, said metal alloy having a vapor pressure below 10.sup.-5 N/m.sup.2 at 300.degree. C.
Dependencies are inferred from the claim text.