小径転動体を有する転がり軸受の転勤疲労寿命に及ぼす転動体サイズと潤滑状態の影響（第2報）: 流体潤滑状態での転動疲労寿命

摘要

The design of the fatigue life of a rolling bearing is based on the Lundberg-Palmgren theory. This theory suggests that the fatigue life of a rolling bearing is influenced by the size of the volume under shear stress. Thus, a rolling bearing with small balls is expected to display a different fatigue life from one with larger balls, even if their maximum contact pressures are the same. The reason for this difference is that the volumes that are under the shear stress between different-sized bearings are different. However, when the contact equivalent radius of a rolling bearing is 1 mm or less, there is no confirmation whether its fatigue life can be designed according to the Lundberg-Palmgren theory. For this reason, the fatigue life of ball bearings with small balls is measured under a fluid lubricating condition. The results obtained are as follows. 1) The difference in ball size is not a significant influence on the fatigue life of the ball bearing. 2) The rolling fatigue life of a rolling bearing with small balls, as well as rolling bearings with typical sized balls, can be designed using the conventional method.%マイクロマシン技術の発展や，機械装置の効率，性能向上の観点から機械装置の小型化が必要とされる．それに伴って転がり軸受の小型化が必要になるが，その設計にあたり信頼性，効率，コスト低減の観点から最適な転がり軸受の寿命設計手法が必要とされる．しかしながら，転がり軸受の小型化にあたり転動体は小径になり，その転動体と軌道の接触領域のサイズが小さくなる条件において，従来のサイズの転動体を有する転がり軸受と同様の疲労寿命予測手法を用いて問題ないかが明らかになっていない．