比特图案化介质磁盘-磁头的气膜静态特性研究

Study on Static Characteristics of Air Bearing Films over Bit Pattern Media in Hard Disk Drives

为了研究比特图案化介质磁盘(bit pattern media,BPM)对磁头静态性能的影响,采用有限元法和牛顿-拉普森迭代法,对不同BPM结构和几何尺寸对应的磁头静态特性进行了计算。研究结果表明,与光滑磁盘相比,在立方形BPM上飞行的浮动块上靠近读写磁头中心区域的表面压力分布呈现离散化特征。随BPM磁单元高度增加,浮动块的最小气膜厚度和气膜承载力逐渐减小,而最大气膜压力等性能的变化则与磁单元分布密切相关。与圆柱形BPM的对比发现,立方形BPM在较小的浮动块翻转角下具有较大的最大气膜压力、承载力和最小气膜厚度,其对应的浮动块具有比圆柱形BPM更好的静态性能,这对BPM的结构及几何参数的设计有重要意义。

A method that combines the finite element method and Newton-Raphson iterative method is applied to study the effects of bit pattern media（BPM）on the static characteristics of slider in the hard disk drive.The static characteristics of sliders with different structures and geometry dimensions of BPM such as pitch angle,roll angle,air bearing film thickness,pressure and load capacity are calculated.The numerical results show that the bit shape and its dimension parameters have significant effects on the static performances of the slider.Compared with the smooth disk,when the slider is flying over the bit pattern media,the pressure distribution in the central region which is close to its read/write head shows a discretization feature.The gas-film load capacity and minimum film thickness of the slider gradually decrease as the bit height increases,while the changes of other characteristics are closely related with the bit distribution.Moreover,a comparison with a cylindrical bit pattern media shows that the smaller roll angle may produce lager maximum film pressure,load capacity and minimum film thickness,and that the static characteristics of the slider flying over cuboidal bit pattern media are better than those over cylindrical bit pattern media.These results are of great significance for the design of structure and geometry parameters of bit pattern media.