Drive assembly for an x-ray tube having a rotating anode

An anode drive assembly for providing rotational support to an anode target within an x-ray tube, the anode drive assembly comprising:.

• (a) a target rotor assembly comprising:
• a cylindrical sleeve that provides the rotor portion of an induction motor that is capable of inducing rotational motion to the sleeve;
• and
• a rotor shaft assembly having a first end connected to the sleeve so that rotation of the sleeve induces a corresponding rotation in the shaft, and a second end connected to the anode target and wherein the rotor shaft is comprised of a material having a first predetermined coefficient of thermal expansion that is substantially equal to that of a material used to construct the anode target;
• (b) a bearing assembly comprising:
• a bearing shaft rotationally supported by a bearing surface, the bearing shaft being comprised of a material having a second predetermined coefficient of thermal expansion that is greater than the first predetermined coefficient of thermal expansion;
• and
• a bearing hub that interconnects the bearing shaft with the target rotor assembly, wherein the bearing hub is comprised of a material having a coefficient of thermal expansion that is intermediate to the first and the second predetermined coefficient of thermal expansion, the bearing hub further comprising:
• an annular flange portion, the flange portion including a raised portion that extends from a surface of the flange portion, wherein the target rotor assembly contacts the bearing hub only along the raised portion.

An x-ray tube, comprising:

• (a) an evacuated envelope;
• (b) an electron source and an anode disposed in a spaced apart configuration within the evacuated envelope so that the anode is arranged to receive electrons emitted by the electron source;
• and
• (c) an anode drive assembly operably connected to the anode and comprising:
• (i) a target rotor assembly including a rotor stem upon which the anode is mounted, the rotor stem substantially comprising a material having a first coefficient of thermal expansion;
• (ii) a bearing assembly including a bearing shaft substantially comprised of a material having a second coefficient of thermal expansion;
• and
• (iii) a bearing hub that interconnects the bearing shaft and the target rotor assembly, the bearing hub substantially comprising a material having a coefficient of thermal expansion with a value between the first and second coefficients of thermal expansion, the bearing hub further comprising:
• a radially extending flange portion having at least one raised structure orthogonally extending from a surface of the flange portion, wherein the raised structure substantially limits direct contact between the bearing hub and the target rotor assembly to the at least one raised structure.

An anode drive assembly suitable for use in conjunction with an anode of an x-ray device, the anode drive assembly comprising:

• (a) a target rotor assembly including a rotor stem adapted to mate with the anode, the rotor stem substantially comprising a material having a first coefficient of thermal expansion;
• (b) a bearing assembly including a bearing shaft substantially comprised of a material having a second coefficient of thermal expansion;
• and
• (c) means for interconnecting the bearing shaft and the target rotor assembly, the means for interconnecting serving to implement an intermediate coefficient of thermal expansion within the anode drive assembly, the intermediate coefficient of thermal expansion having a value between the first and second coefficients of thermal expansion, the means for interconnecting further comprising means for resisting the transfer of heat from the target rotor assembly to the bearing shaft.

An x-ray tube, comprising:

• (a) an evacuated envelope;
• (b) an electron source and an anode disposed in a spaced apart configuration within the evacuated envelope so that the anode is arranged to receive electrons emitted by the electron source;
• and
• (c) an anode drive assembly operably connected to the anode and comprising:
• (i) a target rotor assembly including a rotor stem upon which the anode is mounted, the rotor stem substantially comprising a material having a first coefficient of thermal expansion;
• (ii) a bearing assembly including a bearing shaft substantially comprised of a material having a second coefficient of thermal expansion;
• and
• (iii) a bearing hub that interconnects the bearing shaft and the target rotor assembly, the bearing hub substantially comprising a material having a coefficient of thermal expansion with a value between the first and second coefficients of thermal expansion, the bearing hub further comprising:
• a radially extending flange portion having at least one ridge orthogonally extending from a surface of the flange portion, wherein the at least one ridge substantially limits direct contact between the bearing hub and the target rotor assembly to the at least one ridge.