Patent ID: 7406149

Claim:
An X-ray computed tomography apparatus comprising: a stationary tubular frame having a cross section formed in a substantially tapered shape with respect to a tube axis; a bearing arranged at a small diameter portion of the stationary tubular frame; a rotational tubular frame which is connected to a movable side of the bearing at one end side thereof and which is formed to have a substantially tapered cross section with respect to the tube axis; an X-ray tube mounted on the rotational tubular frame; an X-ray detector which detects an X-ray that is emitted from the X-ray tube and transmitted through a target to be inspected; a rotational position detecting device which detects a rotational position of the X-ray tube in response to the rotation of the rotational tubular frame; a computer section which reconstructs tomographic image data on the target to be inspected based on an output of the X-ray detector and a rotational position of the X-ray tube detected by the rotational position detecting device; a ring shaped rotor having a rotor core and a permanent magnet disposed and fixed at a link portion of the rotational tubular frame, the permanent magnet being adopted to rotate the rotational tubular frame, the permanent magnet configuring a plurality of magnetic poles on an outer periphery side of the rotor core; a stator which is at an outer periphery side of the rotor and which is fixed with respect to an inner periphery face of the stationary tubular frame via a predetermined gap from the rotor; and a magnetic pole position detecting device which detects a magnetic pole position of the rotor; a slip ring disposed and fixed at a large diameter portion of the rotational tubular frame, the rotational tubular frame fixed in abutment with the rotor core, the slip ring configured to supply power to the X-ray tube.