Rotary-anode type X-ray tube

A rotary-anode type X-ray tube comprising:

• an anode target;
• a rotary structure which has a rotation center axis and to which said anode target is fixed;
• a stationary structure, coaxially arranged with said rotary structure, for rotatably supporting said rotary structure;
• a hydrodynamic bearing formed between said rotary structure and said stationary structure, said hydrodynamic bearing having a gap in which a metal lubricant is applied, the metal lubricant being in liquid state during rotation of said rotary structure, said hydrodynamic bearing including a reaction layer in contact with the metal lubricant, the reaction layer having been reacted with at least one element of gallium (Ga), indium (In), bismuth (Bi) or tin (Sn);
• and
• a lubricant storage chamber for receiving the metal lubricant, said lubricant storage chamber formed by at least one of said stationary and rotary structures, the one of said stationary and rotary structures being arranged on the rotation center axis, said lubricant storage chamber communicate with the gap in said hydrodynamic bearing.

A rotary-anode type X-ray tube comprising:

• an anode target;
• a rotary structure which has a rotation center axis and to which said anode target is fixed;
• a stationary structure, coaxially arranged with said rotary structure, for rotatably supporting said rotary structure;
• a hydrodynamic bearing formed between said rotary structure and said stationary structure, said hydrodynamic bearing having a gap in which a metal lubricant is applied, the metal lubricant being in liquid state during rotation of said rotary structure, said hydrodynamic bearing including a bearing surface formed on at least one of said stationary and rotary structures, and said bearing surface including a material selected from the group essentially consisting of nitride ceramic, carbide ceramic, and carbonitride ceramic.