| 摘要 |
PURPOSE:To reduce change in clearance of ball bearing due to thermal expansion of X-ray tube in the axial direction, stabilize rotation and reduce noise level by using a material having a thermal expansion coefficient smaller than that of stationary side as the cylindrical material which specifies interval of bearing device in the rotating side material. CONSTITUTION:An anode target 1 is coupled to the one end of a drive motor rotor 3 and two ball bearings 4 are fixed in the specified interval with the cylindrical member 6 in the outer ring (rotating) side and the cylindrical member 7 in the inner ring (stationary) side. The compositions of cylindrical member 6 in the outer ring side is, for example, Fe-40Ni-0.45Mn, while the cylindrical member 7 in the inner ring side is SUS316. The cylindrical member 9 of the outer ring has the thermal expansion of about 1/4 the thermal expansion of the cylindrical member 78 in the inner ring side. Since the thermal expansion difference is generated even in the radius direction when the outer ring side becomes longer than the inner ring side, elongation in the axial direction can be eliminated sufficiently by the groove at the running surface of ball bearing and the clearance in the axial direction which is equal to the initial condition or more can be assured. |
