Rotary anode type X-ray tube

#This application is the National Phase of International Application No. PCT/JP02/08699 filed Aug. 29, 2002, which designated the U.S. and was published on Mar. 6, 2003 as International Publication No. WO 03/019610 A1, which is based upon and claims the benefit of priority from prior Japanese Patent Application Nos. 2001-259087, filed Aug. 29, 2001, 2001-264281, filed Aug. 31, 2001, and 2002-018592, filed Jan. 28, 2002, the entire contents all of which are incorporated herein by reference.

#The present invention relates to a rotary anode type X-ray tube using dynamic pressure type sliding bearings.

#The rotary anode type X-ray tube has a structure that an anode target for radiating X-rays is rotatably supported by a rotating mechanism, and an electron beam is emitted to the anode target rotating at a high speed to irradiate the X-rays from the anode target. The rotating mechanism for supporting the anode target is comprised of a rotary body, a stationary body and the like, and bearings are disposed between the rotary body and the stationary body. For a bearing section, there is used a rolling-element bearing such as a ball bearing or a dynamic pressure type sliding bearing which has helical grooves formed on a bearing surface and supplies a liquid metal lubricant such as gallium (Ga) or gallium (Ga)-indium (In)-tin (Sn) alloy to the helical grooves and the like.

#FIG. 1 is a vertical sectional diagram showing a structure of the main part of the rotary anode type X-ray tube according to a first embodiment of a first aspect of the invention.

#FIG. 2 is a vertical sectional diagram showing a structure of the main part of the rotary anode type X-ray tube according to a second embodiment of the first aspect of the invention.

#FIG. 3 is a vertical sectional diagram showing a structure of the main part of the rotary anode type X-ray tube according to a third embodiment of the first aspect of the invention.

#Embodiments of the invention will be described with reference to the accompanying drawings.

#First, embodiments of the rotary anode type X-ray tube according to a first aspect of the invention will be described. FIG. 1 is a vertical sectional diagram showing a structure of the main part of the rotary anode type X-ray tube according to a first embodiment of the first aspect of the invention. A rotary anode type X-ray tube 20 shown in FIG. 1 has, for example, a glass vacuum vessel 21. The vacuum vessel 21 shown in FIG. 1 is its part. A disk-shape anode target 22 for emitting X-rays is disposed in the vacuum vessel 21. The anode target 22 is formed of a heavy metal or the like.

#The anode target 22 is fixed to the outer peripheral surface of a cylindrical rotary body 23 of a high melting-point metal with a nut 24. The rotary body 23 configures a rotating portion of a rotating mechanism 25 for rotatably supporting the anode target 22. The rotary body 23 has a first section 231 located on the top, a second section 232 having an outside diameter larger than that of the first section and located at the middle portion and a third section 233 having an outside diameter larger than that of the second section 232 and located below the second section 232. A high conductive cylindrical rotary body 26 is connected to a part of the third section 233.