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Study on Self-Induced Contact Bouncing Vibration and Stable Contact Sliding Conditions

自感接触弹跳振动与稳定接触滑动条件的研究

基本信息

批准号：
15360081
负责人：
ONO Kyosuke
金额：
$ 10.11万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15360081/
关键词：
Magnetic Disk Drive Near-Contact Flying Head Slider Dynamic Contact Behavior Contact Characteristics Self-Excited Vibration Stable Flying Condition Adhesion Force Friction Force 高速道的接触現象

项目摘要

1)Experimental measurement and analysis of the unstable bouncing vibrationWe experimentally clarified the details of the contact bouncing vibration of two kinds of currently used flying head slider in near-contact regime by decreasing its flying height by reducing the ambient pressure. As a result, we found that the critical flying height (take-off height) can be decreased by increasing static pitch angle. This is because the adhesion force can be decreased by a decrease in contact area in which the meniscus can form. The unstable bouncing vibration is induced in such a way that the trailing edge is first attracted to the disk and thereby the friction force acting on the slider excites the bouncing vibration. The unstable vibration mode is likely to be the lower pitch mode, but theoretically is close to the anti-resonance mode of the slider-air bearing system. Unstable vibration mode is a coupled vibration between translation and pitch motion with a small phase shift and does not conta … More in the rolling motion.2)Theoretical study of the bouncing vibration of a 2-DOF slider model considering the nonlinearity of air bearing stiffnessContact characteristics between slider pad and disk with a small asperity height is first studied, including meniscus force and bulk deformation. Then we found that the contact characteristics can be modeled by the contact stiffness in bulk deformation, meniscus adhesion force, and pull-in and pull-off separations for smooth disks to be used for a high-density recording. Next, by using these contact characteristics, we analyzed the bouncing vibration of a 2-DOF slider model considering a shearing friction force of lubricant in addition to the ordinary dry friction force. The, we found that the hysteresis phenomena of the bouncing vibration, the mode of the bouncing vibration, its destabilizing process can well be estimated by this theory. From parametric study, we found that the critical flying height (take-off height) can be decreased by decreasing adhesion force, friction force, and shearing friction force of the lubricant, and increasing air bearing stiffness, particularly trailing air bearing stiffness.3)Identification of contact force, adhesion force and damping force by means of collision motion of a spherical slider on stationary magnetic disks.By using glass hemispherical sliders of 1 and 2 mm in radius, and magnetic disks of 0,1,2,3 nm lubricant thickness with/without UV treatment, we experimentally measured the displacement, velocity and acceleration of the slider motion by means of digital laser Doppler vibrometer, and identified the contact reacting force and adhesion force acting on the slider at the instant of separation. As a result, we found that the contact reacting force can well be predicted by Hertzian contact theory and that the dynamic adhesion force is almost equal to the static meniscus force. The adhesion force tends to decrease from the theoretical value of the meniscus force when the radius of contact increases, the separation velocity increase, and the bonded ratio increases due to UV irradiation treatment. This indicates that a meniscus bridge can hardly form in these conditions. These results can justify the fact that the adhesion force between a flying head slider and magnetic disk is caused not by Van del Waals force but by meniscus force. Less

1)非稳定弹跳振动的实验测量与分析通过降低环境压力来降低浮动磁头的浮动高度，实验研究了两种浮动磁头在近接触区的接触弹跳振动。结果表明，增大静态俯仰角可以降低临界飞行高度（起飞高度）。这是因为可以通过减小其中可以形成弯月面的接触面积来减小粘附力。不稳定的跳动振动是以这样的方式引起的，即后缘首先被吸引到盘上，从而作用在滑块上的摩擦力激发跳动振动。不稳定的振动模式可能是下节距模式，但理论上接近滑块-空气轴承系统的反共振模式。不稳定振动模式是平移和俯仰运动之间的耦合振动，具有小的相移，并且不与振动相接触。 ...更多信息 2）考虑空气轴承刚度非线性的二自由度滑块模型的弹跳振动理论研究首先研究了具有小微凸体高度的滑块与磁盘的接触特性，包括弯月面力和体变形。然后，我们发现，接触特性可以建模的接触刚度在体变形，弯月面的粘附力，和拉在和拉脱分离的光滑磁盘用于高密度记录。接着，利用这些接触特性，我们分析了一个2自由度滑块模型的弹跳振动，除了普通的干摩擦力，还考虑了润滑剂的剪切摩擦力。同时，我们发现，该理论可以很好地估计跳跃振动的滞后现象、跳跃振动的模式及其失稳过程。通过参数研究，我们发现临界飞行高度（起飞高度）可以通过减小润滑剂的粘附力、摩擦力和剪切摩擦力以及增加空气轴承刚度，特别是后空气轴承刚度来减小。3）接触力的识别，本文用1.5mm厚的玻璃半球形滑块，通过对球形滑块在静止磁盘上的碰撞运动所产生的粘着力和阻尼力的分析，得出了球形滑块在静止磁盘上的碰撞运动所产生的粘着力和阻尼力和2 mm的滑块，以及润滑剂厚度为0、1、2、3 nm的经过UV处理的磁盘，用数字激光多普勒测振仪对滑块运动的位移、速度和加速度进行了实验测量，确定了滑块分离瞬间的接触反作用力和附着力。结果表明，动态附着力与静态弯月面力几乎相等，可以用赫兹接触理论来预测。随着接触半径的增大、分离速度的增大以及紫外光照射处理后的结合率的增大，附着力趋于从弯月面力的理论值下降。这表明在这些条件下几乎不能形成弯月面桥。这些结果证明了磁头浮动块与磁盘之间的粘附力不是由货车范德华力引起的，而是由弯月面力引起的。少