Analysis of Radial Air-Shear Force on Magnetic Disks for Reducing the Spin-off of Lubricants

To reduce the spin-off of lubricants, which is caused by the radial component of air-shear force on a magnetic disk, we analyzed the air-velocity distribution and the air-shear force by using the three dimensional large eddy simulation (LES) and the finite-element method. A sensitivity analysis of five design parameters showed that disk/arm clearance and arm thickness had greater effect on the mean radial air-shear force than the other three parameters. The air-shear force was decreased when these two parameters became small. The force on the disk with the optimum parameters is 12% less than the force on a current design disk. The optimized drive can thus be operated at 14% higher rotational speed with the same reliability as current drives.