Dynamic pressure bearing for an X-ray tube having a rotary anode.

摘要

A dynamic pressure bearing for an X-ray tube having a rotary anode (13) has a cylinder member (16) for supporting the anode (13) and a shaft member (15) fitted in the cylinder member (16). Between the cylinder member (16) and the shaft member (15) is formed a given clearance (t), which is filled with lubricant (20) formed of either gallium or gallium alloy. The shaft member (15) has on its outer peripheral surface a plurality of grooves (15c) for generating dynamic pressure. A body (16b, 15b) of each of the cylinder member (16) and the shaft member (15) is formed of ceramic which has corrosion resistance against gallium and gallium alloy of the lubricant. The grooves (15c) for generating dynamic pressure can be easily worked on the body (15b) of the shaft member (15) because it is formed of ceramic having a good workability. Glass, tantalum or tantalum alloy can be used instead of ceramic.