【作者】 王林；

【导师】 董惠娟；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2009， 硕士

【摘要】 磁头是硬盘读写数据的重要部件之一,读写单元就安装在磁头的浮动块上,而浮动块粘接在悬架的挠臂舌尖部分,绕着窝点运动使磁头适应盘面的高低变化。窝点和舌尖的法向和径向微动会造成窝点的磨损,产生的磨屑会严重污染盘面,影响磁头的飞行状态及降低硬盘的可靠性和寿命。针对窝点与舌尖的微动磨损这一问题,本文从接触力学的角度出发,对窝点与舌尖的接触状态进行力学分析及数值仿真,分析载荷、粗糙度、材料特性等参数对磨损的影响,可为研究窝点与舌尖的微动磨损和疲劳损伤机理及控制方法奠定基础,对进行窝点与舌尖的微动磨损实验及优化设计具有一定的指导作用。通过对磁头悬架窝点与挠臂舌尖的接触状态进行理论分析及计算,采用ANSYS有限元仿真方法,建立了在完全粘着条件下悬架窝点与挠臂舌尖的接触有限元模型。研究表明随着法向力的增加,窝点和舌尖接触的最大静摩擦力增加,窝点和舌尖的相对滑动变的更加困难,不容易发生磨损,但是,法向力过大,在接触表面下方出现的塑性变形增加,窝点可能产生疲劳破坏。研究了舌尖厚度和弹性模量对窝点Von Mises应力分布和Von Mises应力大小的影响,舌尖的厚度越小,在大于预紧力作用下,窝点的应力值越小,当舌尖厚度超过一定值时,尺寸的影响可以忽略。相同的外力作用下,舌尖的弹性模量越小,窝点的应力值越小,则不容易发生疲劳破坏。仿真了舌尖受预紧力作用下以及预紧力和气浮力共同作用下窝点的塑性应变情况,得出了窝点最大塑性应变出现位置及接触表面的塑性变形分布,揭示了磁头在工作和非工作状态下,疲劳裂纹可能的萌生位置和接触表面可能发生磨损的区域。随着切向载荷的增加,塑性变形区域增大,塑性应变值增大,越容易发生磨损。通过对悬架窝点和挠臂舌尖的粗糙接触模型进行研究,得出接触表面的粗糙度越小,表面的塑性指数越小,窝点和舌尖发生相对滑动越困难,越难磨损,并且存在着一个与塑性指数相关的法向力阈值,当法向力超过阈值时,接触表面的粗糙度影响可以忽略,窝点和舌尖的粗糙接触问题可以用光滑的球体和平面模型解决。更多还原

【Abstract】 Magnetic head is one of the important component of hardware to read and write data, the read and write element is installed on the slider which is conglutinated onto flexure’s tongue part from suspension and circulates around dimple to adapt the magnetic head to the variation of height of disk surface. normal and tangential fretting of dimple and tongue may cause wear to dimple, produce chippings, create heavy pollution to disk surface and influence the flight state and also the reliability and longevity of hardware would be reduced. Aim at the fretting wear of the dimple and tongue, studying on the contact state of the dimple and tongue and the impact of load, roughness, material properties etc. on the wear from the point of contact mechanic, can lay a foundation to the research on the production mechanism and controlling method of fretting wear and chippings of dimple and tongue, and also serve the instructional function to the fretting and wear experiment and optimal design of dimple and tongue.This paper have constructed and analyze a finite element model under full stick condition using finite element analysis based on the theoretical analysis of the elastic-plastic contact condition and contact state between the dimple and tongue of the magnetic head suspension. The research has showed that with the increase in normal load, the maximum static friction force increase, the dimple and tongue slide more difficulty and not prone to wear and tear, but if the force is too large, plastic deformation appears at the place beneath the contact surface, fatigue failure may have.After the research to the influence of the tongue thickness and Young modulus to the distribution and Von Mises stress of dimple, it has showed that the thinner the tongue under the force larger than preload, the smaller the stress of dimple. The influence coming from the dimension can be ignored as the thicknesses of tongue exceed certain degree. The smaller the Young modulus of tongue, the smaller the stress of dimple under the same normal loading and the more difficult the fatigue failure.Through the simulation of the plastic deformation of the dimple and tongue under the preloading and the combined preloading and air buoyancy force, it has find out the maximum plastic strain location and the plastic deformation in the osculated surface, revealing the possible initiation location of the fatigue crack and the region that wear may occur in contact surface in the working and non-working state. As the tangential load increases, plastic deformation region increase, the value of plastic strain increases, the more prone to wear and tear.Through the rough construction of contact mode of the suspension dimple and flexure tongue, it has showed that the less the roughness of contact surface, the smaller the plastic index of surface, the smaller the stress of dimple under the same normal loading and the more difficulty the wear happens. it denotes the existence of threshold value of normal loading in relation to plastic index. As the normal loading exceeds the threshold value, the influence coming from the roughness can be ignored.更多还原