Patent ID: 7324629

Claim:
A rotary anode X-ray tube, comprising: a vacuum envelope; a cathode arranged within the vacuum envelope, which emits an electron beam; a rotary anode arranged within the vacuum envelope, on which the electron beam impinges to generate X-rays; a rotary structure supporting the rotary anode, including a cylindrical portion having two open ends and a rotor section provided for generating a rotating force to rotate the cylindrical portion together with the rotary anode, the rotary anode fixed to the cylindrical portion and arranged within the vacuum envelope, the rotary anode being arranged around the cylindrical portion so that a center of gravity of the rotary anode with the rotary structure is in the cylindrical portion; a stationary shaft having two ends and an axis, and including a middle section having two ends, which is fitted into the cylindrical portion, a first section extending along the axis between one end of the middle section and one end of the stationary shaft and having a first shaft length, a second section extending along the axis between the other end of the middle section and the other end of the stationary shaft and having a second shaft length, the first shaft length being larger than the second shaft length, a transverse stiffness of the second section being larger than a transverse stiffness of the first section, and the center of gravity is positioned in the middle section; a dynamic pressure radial bearing arranged between the cylindrical portion and the middle section of the stationary shaft; and first and second supporting sections arranged within and fixed to the vacuum envelope, the second supporting section fixedly supporting the second section such that the second section does not slide, and the first supporting section supporting the first section in such a manner that the first section is configured to slide on the first supporting section.