| 摘要 |
<p>PURPOSE:To improve wear resistance of a bearing and reduce centrifugal force acting on balls and contact surface pressure between a raceway ring and the balls by partially using balls made of ceramics in at least a partial group of radial ball bearings for protection located on plural places. CONSTITUTION:In case of high speed touch down, as each ball 11 is made of ceramics, its hardness is high and its wear resistance is improved, and as the density of ceramics is small, centrifugal force acting on the ball 11 becomes smaller and contact surface pressure between the ball 11 and an outer ring 13 becomes smaller. As the coefficient of linear expansion of the ceramics is small, clearance change in this bearing generated by heating is smaller than that of a steel ball and deformation of the ball 11 is small and its rotation becomes smoother, because coefficient of elasticity of the ceramics is larger. Therefore, durability of the ball 11 can be improved by making the ball out of ceramics.</p> |
