Theoretical prediction of ramp loading unloading process in hard disk drives

Air bearing slider dynamic performance during the ramp loading and unloadin g processes was investigated theoretically in this paper The air bearing wa s modeled by the modified compressible Reynolds equation, and it was sah ed by the finite volume method. Slider dynamic equations were derived in this paper to include the ramp loading/unloading mechanism. These two sets of c oupled equations were salved iteratively Bath Tripad and negative pressure air bearing (NPAB) were included in the analysis. Effects of loading/unload ing velocity, disk rotational speed, as well as suspension flexure stiffnes s, were investigated. Slider-disk impact will occur during the Tripad loadi ng process, especially, at high loading velocity. On the other hand this im pact can be avoided for an NPAB at loading velocity up to 200 mm/s. However , an NPAB requires a longer unloading time due to its suction force. This u nloading process is further delayed if a soft flexure is combined with an N PAB.