Rotating anode X-ray tube

A rotating anode X-ray tube comprising:

• a fixed body having a radial sliding bearing surface on a side surface thereof and a channel therein through which a coolant flows;
• a rotor including a discoid large-diameter portion, which has a recess fitted with one end portion of the fixed body with a clearance therebetween and constitutes an anode target, and a small-diameter portion, which surrounds the side surface of the fixed body, has on an inner surface thereof a radial sliding bearing surface which faces the aforesaid radial sliding bearing surface with a clearance, and is united with the large-diameter portion at one end portion thereof;
• a lubricant filling the clearances;
• a cathode arranged opposite to the anode target of the large-diameter portion;
• and
• a vacuum envelope which contains the fixed body, the rotor, the lubricant and the cathode, and fixes the fixed body at another end portion of the fixed body situated opposite the one end portion of the fixed body fitted in the recess.