2013 年 79 巻 6 号 p. 523-528
Hydrodynamic grooved bearings are widely used in the HDD(Hard Disk Drive) mechanism for rotary precision, noise reduction, and superior shock-resistance. Therefore, many studies have been made, but most of them have dealt with the bearing design or vibration analysis. This report studies the viscosity increase of the lubricant that affects the life of the hydrodynamic grooved bearing, which compares the viscosity increase in the continuous driving test in the bearing with that in the accelerated high temperature test. The viscosity increase of the lubricant in the accelerated high temperature test is bigger than that in the continuous driving test in the bearing. Both tests generate the same materials. So, Marangoni effect causes the smaller viscosity increase of the lubricant in the continuous driving test in the bearing. The temperature gradient in the bearing causes the low evaporate materials with high viscosity to move to the gas-liquid boundary, which prevents the low viscous material from evaporating, resulting in the smaller viscosity increase. Therefore, the life of the lubricant in the bearing is longer than what is expected by Arrhenius equation in the accelerated high temperature test.
