|Budget Amount *help
¥3,600,000 (Direct Cost : ¥3,600,000)
Fiscal Year 2003 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 2002 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 2001 : ¥1,700,000 (Direct Cost : ¥1,700,000)
This study proposes the combination of some hydrodynamic pressure shapes formed on the end surface or on the annular surface of porous oil impregnated sintered bearing as a DC spindle motor's bearing system, and examines experimentally to optimize the hydrodynamic shape combination as thrust-radial composite bearing. Hydro Wave Bearing or Pump In as a thrust hydrodynamic shape, and Herringbone, Three Lobed Type or Sleeve (as a standard) as a radial hydrodynamic shape, were proposed, and the total of six kinds of combinations was produced as thrust-radial composite bearing.
Floatation, temperature rise, friction torque and shaft whirling, such as the lubrication characteristics we reexamined experimentally. As experimental results, it was confirmed that low shaft whirling, energy-saving and life-longevity of bearing itself, were achieved by hydrodynamic pressure interaction of thrust-radial composite bearing. These experimental results clarified the following points.
1)At the time of floatation characteristic testing, radial hydrodynamic pressure shapes are dominant, floatation characteristic can be improved with the multiplier effect due to adding thrust hydrodynamic pressure shape to this. Furthermore, the satisfactory floatation characteristic which is most stabilized was obtained with combination of the PIN HB. (Almost it becomes complete floatation condition more than 1000 rpm)
2)On the measurements of temperature rise and friction torque, the radial hydrodynamic pressure shape also decrease both characteristic value in order of the TLT<SLV≦HB, it is especially possible for TLT to decrease in half of other combination characteristic value regardless of thrust hydrodynamic pressure shape.
3)The tendency of second point is even with durability test, for the PIN-TLT which is most superior in oil consumption rate, you can expect about twice capability of other combination with respect to energy-saving and bearing life-longevity.