Rolling bearing for main spindle of machine tool

TLDR: In this article, the authors proposed a method to prevent deterioration of accuracy based on thermal displacement of a main spindle, by a method wherein an inner and outer races, whose space between them is sealed, are made of a bearing material whose conductivity is poor and a lubrication hole and oil drain hole for lubricating oil are provided on the outer race.

Abstract: PURPOSE:To prevent deterioration of accuracy based on thermal displacement of a main spindle, by a method wherein an inner and outer races, whose space between them is sealed, are made of a bearing material whose conductivity is poor and a lubrication hole and oil drain hole for lubricating oil are provided on the outer race. CONSTITUTION:An inner and outer races 1, 2 are made of a bearing material, whose thermal conductivity is poor, such as fine ceramics, a roller 3 is arranged between the inner and outer races 1, 2, a lubrication hole 5 for lubricating oil is provided on one side out of both side inner circumferential surfaces adjoining to a raceway groove 4 of the outer race 2, an oil drain hole 6 is provided on the other side of the same, and an annular space between the inner and outer races 1, 2 is sealed by sticking annular shield plates 7 on the inner circumference of both ends of the outer race 2. In consequence of the above, heating of the inside of a bearing is hard to transmit to a main spindle and housing of a machine tool and, moreover, the inside of the bearing is cooled by the circulating lubricating oil or the lubricating oil and air.