No abstract

A reliable model of the heat transfer at the air bearing surface of a flying head slider is important for treating thermomechanical aspects of the molecular gas lubrication system in today’s hard disk drives. This article proposes a new model for heat transfer in the head disk interface, which considers both the heat conduction and viscous dissipation. The conduction heat flux based on this model shows better agreement with the numerical results of the linearized Boltzmann equation than existing models derived from the temperature jump theory. The viscous dissipation of plane Couette flow as well as that of plane Poiseuille flow in the gas film is analyzed using the energy conservation equation instead of the linearized Boltzmann equation, which is incapable of calculating the viscous dissipation at the boundaries. The new model gives simple analytical expressions for the heat flux contributed by heat conduction and viscous dissipation, and it is applicable to numerical thermomechanical simulations of the slider’s performance.

Slip-corrected Reynolds equations have not been widely used in the air bearing simulations for the head-disk interface in hard disk drives since Fukui and Kaneko [Trans ASME J Tribol 110:253-262, 1988] published a more accurate generalized lubrication equation (FK model) based on the linearized Boltzmann equation for molecular gas lubrication. However, new slip models and slip-corrected Reynolds equations continue to be proposed with certain improvements or with the more physical basis of kinetic theory. Here, we reanalyze those slip models and lubrication equations developed after the FK model was published. It is found that all of the slip-corrected Reynolds equations are of limited use in the air bearing simulations, and that these new slip-corrected Reynolds equations cannot replace the FK model for calculating an accurate pressure distribution of molecular gas lubrication.

No abstract

A six-degree-of-freedom slider dynamic simulator is developed to analyze the slider's motion in the vertical, pitch, roll, yaw, length and width directions. The modified time-dependent Reynolds equation is used to model the air bearing and a new second order slip model is used for a bounded contact air bearing pressure. The simulator considers the air bearing shear acting on the air bearing surface and the slider-disk contact and adhesion. Simulation results are analyzed for the effects of the disk surface micro-waviness and roughness, skew angle, sliderdisk friction and micro-trailing pad width on the vertical bouncing, down-track and off-track vibrations of a microtrailing pad partial contact slider.