Air Bearing Design to Prevent Reverse Flow from the Trailing Edge of the Slider

A simulation approach that relies on an analysis of the flow patterns closest to an air bearing surface (ABS) was used to predict the lubricant accumulation on the ABS of a head slider. The lubricant accumulation patterns obtained through the simulation were in good agreement with experimental results and with our experimental apparatus. We used this method to study and analyze flow pattern droplets close to the trailing edge of a number of sliders and found that there was a reverse flow from the slider’s trailing edge on both sides of the trailing pad and behind the read/write element, which could result in a lubricant accumulation on the slider surface close to the trailing edge of a slider and thus lead a transient slider vibration and magnetic-signal loss in a hard disk drive. Further simulations and analyses revealed that the reverse flow is dependent on the depth of slider surface on adjacent to the trailing edge of the slider, and that if the depth is less than a critical depth, which is dependent on the velocity of the disk, the reverse flow could be eliminated. On the basis of these findings, we propose a new ABS design concept for effectively suppressing the reverse flow of lubricants from the trailing edge of the slider. In this concept, the slider has a “smooth flow pad” and the depths of outlet recesses are specified as being smaller than the critical depth. It was confirmed by both simulation and experiment that lube accumulation on the slider surface is obviously decreased and the reliability of a hard disk drive with this air bearing design is consequently improved.