共查询到18条相似文献,搜索用时 609 毫秒
1.
用动态飞行高度测试仪DFHT测试了在不同转速下磁头的飞高、俯仰角和侧翻角,磁头飞行高度和俯仰角,随着磁盘转速的增大而增大,而侧翻角则先增加后减小。由结果可以看出,随着转速的增加,俯仰角变化比较大,说明磁盘转速对磁头的左右翻转运动的影响比较大,而侧翻角变化相对比较微弱,用动态电性能测试机测试相同情况下不同转速下输出磁信号的幅值,可以看出随着飞高的增加,输出信号的幅值也随着减小。 相似文献
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Bai Shaoxian Peng Xudong Meng Yonggang Wen Shizhu.Zhejiang University of Technology Hangzhou .State Key Laboratory of Tribology Tsinghua University Beijing 《中国机械工程》2009,(1)
根据热力学理论,建立了硬盘磁头热力学分析模型,利用数值方法分析了绝热过程中热效应及热蠕流效应对磁头承载能力、飞行姿态等性能的影响,并与实验结果进行了对比分析。数值分析结果表明,绝热过程中热蠕流效应对磁头的压力分布和承载力没有明显影响,但热效应对气体黏度和磁头飞行姿态影响明显。热效应使气体黏度和承载能力增加,从而使磁头飞行高度和俯仰角增大,但对侧翻角没有明显影响。理论分析与实验结果的对比分析表明,磁头的飞行过程不是绝热过程。 相似文献
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采用优化设计方法优化一种皮米磁头的形状,能够降低磁头飞高,提高硬盘的存储密度及磁头的飞行稳定性。优化设计以磁头俯仰角和形状尺寸为约束,以磁头在磁盘半径方向内侧、中间、外侧稳定飞行时的飞行高度和侧倾角与优化目标值间的波动最小为优化目标建立优化模型,采用模拟退火算法对优化模型求解。优化结果表明,优化后磁头的飞浮高度可从7 nm降低到5 nm,而且磁头寻轨时磁头的稳态飞行波动得到明显改善,能够满足工程上对飞高的波动性要求。最后,比较了提高磁盘转速后初始磁头和优化磁头的稳态飞行特性,结果表明磁盘转速对优化结果有影响,改变磁盘转速建立新的优化模型可以得到适合新条件的优化磁头。 相似文献
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刘丽华 《机械工程与自动化》2009,(6):161-163
分析了磁头飞行角度调校仪器不同工位测量磁头俯仰角和翻转角之间的相关性,并简单介绍了角度调校方法.实验结果表明,用此方法,减小了磁头的安装误差,使该仪器的角度测量精度得到了提高. 相似文献
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计算机硬盘向小型化和高密度存储量方向发展,硬盘磁头的飞行高度越来越低,同时磁头的厚度也越来越小,更容易发生热变形,从而影响飞行高度。目前产品设计中采用多种措施降低热变形以图保证飞行高度稳定性,影响了其他性能。用数值仿真的方法分析磁头热变形与其稳态飞行高度之间的关系,再利用高阶滑移模型修正超薄气膜雷诺方程,采用加权余量法和有限元方法求解气膜压力方程组,得出气膜压力分布,建立磁头在盘片上飞行的简化物理模型,分析磁头热变形与稳态飞行高度之间的关系。计算结果表明,一定的热变形反而有利于稳定磁头飞行高度。 相似文献
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为了提高寄生式时栅行波信号的质量和传感器的测角精度,研究了离散式测头安装误差对传感器测角精度的影响。介绍了寄生式时栅的结构组成和工作原理,建立了三维仿真模型,应用Ansoft Maxwell仿真软件对测头与转子不同间隙、测头的俯仰角和偏摆角大小变化对传感器测角精度的影响进行了仿真实验分析,同时应用84对级的寄生式时栅搭建实验平台进行了实际实验验证。仿真和实验结果显示:安装误差中的间隙、俯仰角、测头的偏摆角等因素变化对传感器测量精度均有影响。间隙变化对测量精度的影响具有规律,可通过建模进行修正。实验所用的84对级的寄生式时栅最佳安装间隙大小为0.2mm。俯仰角、偏摆角的变化对测量精度的影响规律变化较复杂,故文中建立了相应的误差补偿模型。本文的研究结果可用于指导传感器的结构优化设计、测头的安装和误差精确补偿,进而提高传感器的测角精度。 相似文献
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针对捷联惯性导航系统(SINS)的安装误差影响管道地理坐标测量精度的问题,提出SINS安装误差标定算法,推导了SINS安装误差动态传递模型,将SINS的俯仰角和航向角安装误差作为状态变量,建立一种新的SINS/里程仪/管道磁标点GPS组合导航模型,利用容积卡尔曼滤波实现俯仰角和航向角安装误差的标定。实验结果表明,该方法安装误差的估计精度为0.2'~0.6'。经误差补偿后,1 km长程管道地理坐标高度测量精度为1.59E-3,水平测量精度可达1.07E-3,能够满足长距离管道地理位置测量精度的工程需要,具有一定的实用性。 相似文献
11.
The flying height sensitivity of pico and femto sliders on air bearing contour design, operating conditions and manufacturing tolerances was studied numerically. A Monte Carlo analysis was performed to evaluate the distribution of flying height, pitch angle and roll angle, assuming the selected independent variables have normal distributions. Two types of pico sliders and one type of femto sliders were modeled and simulated. The results show that flying height is strongly influenced by the contour design of the air bearing slider. The resulting distributions of flying height, pitch angle and roll angle are near Gaussian. 相似文献
12.
With the decrease in slider flying height, slider flying instability caused by slider–disk interactions is becoming a big
concern. Novel technology has to be employed to further improve our understandings about slider–disk interaction. In this
work, a slider flying height-attitude testing (3D) system was employed to study slider–disk interaction during a slider landing
process to demonstrate its capability for the application. It is shown that great details of slider–disk interactions and
subtle variations of the slider flying attitude during the landing process can be revealed with the 3D system. Slider dynamic
flying height and attitude (pitch and roll angles) during the landing process can be determined from the data recorded in
one test. Furthermore, analysis in frequency domain can be done not only on flying height, but also on pitch and roll angles
directly. It is found that the slider landing process can have different stages during which slider performance and characteristics
of slider–disk interaction are different. 相似文献
13.
Deng Pan Andrey Ovcharenko Min Yang Filippo Radicati Frank E. Talke 《Tribology Letters》2014,53(1):261-270
A precision spin stand was used to study the effects of pitch static angle and roll static angle on lubricant transfer between a disk and a slider in a hard disk drive. The lubricant distribution on the slider was determined by time-of-flight secondary ion mass spectrometry, while the lubricant distribution on the disks was obtained using optical surface analysis. Lubricant transfer from the disk to the slider was found to increase as a function of the pitch static angle of the slider. Negative roll static angles were found to have a larger effect on lubricant transfer and the formation of lubricant moguls than positive roll static angles. Suspension frequencies and pitch mode frequencies were observed in the lubricant mogul patterns for negative roll static angles. 相似文献
14.
A numerical model is developed to study the effect of texture on air bearing sliders for large Knudsen numbers. The effect
of texture location, texture size, and density on the pressure generation is studied. First, a textured plane slider parallel
to the disk surface is investigated, and the texture parameters are determined that result in optimum pressure generation.
Then, a plane inclined slider is studied using optimum texture parameters found in the parallel slider case. Thereafter, the
effect of texture on the steady state flying characteristics of an actual magnetic recording slider is investigated. Finally,
the flying height modulation, pitch, and roll motion of a textured slider (pico and femto form factors) are determined numerically
by exciting the slider using a step on the disk. Comparison of the results for textured and untextured sliders is made. It
is found that textured sliders show better dynamic performance compared to the untextured sliders in terms of stiffness and
damping. 相似文献
15.
The use of patterned media is a new approach proposed to extend the recording densities of hard disk drives beyond 1 Tb/in.2. Bit-patterned media (BPM) overcome the thermal stability problems of conventional media by using single-domain islands for
each bit of recorded information, thereby eliminating the magnetic transition noise (Albrecht et al., Magnetic Recording on
Patterned Media, 2003). Considering steady state conditions, we have transferred the pattern from the disk surface onto the
slider surface and have investigated the pressure generation due to the bit pattern. To reduce the numerical complexity, we
have generated the bit pattern only in the areas of the slider near the trailing edge, where the spacing is small. Cylindrical
protrusions were modeled using very small mesh size on the order of nanometers to obtain the flying characteristics for the
entire slider air bearing surface (ABS) using the “CMRR” finite element Reynolds equation simulator (Duwensee et al., Microsyst
Technol, 2006; Wahl et al., STLE Tribol Trans, 39(1), 1996). The effect of pattern height, pattern diameter, slider skew angle,
and slider pitch angle on flying height of a typical slider is investigated. Numerical results show that the flying height
decreases for a patterned slider and the change in flying height is a function of the pattern height and ratio of the pattern
diameter to the pattern pitch. In comparison to discrete track media, the flying height loss is larger for a patterned slider
disk interface for the same recessed area of pattern. 相似文献
16.
The air bearing’s response to regions of elevated temperature on its bounding surfaces (the slider and disk) may be an important consideration in the head–disk interface design of heat-assisted magnetic recording (HAMR) systems. We implement the general non-isothermal molecular gas lubrication equation into an iterative static solver and dynamic air-bearing solver to evaluate the effect of localized heating of the air-bearing surface (ABS) due to the near-field transducer (NFT). The heat-dissipating components in our simplified HAMR design are the NFT, laser diode, and thermal flying height control (TFC) heater. We investigate the effect of each HAMR slider component on ABS temperature and thermal deformation and the slider’s flying height. The NFT induces a localized thermal spot and protrusion on the larger TFC bulge, and it is the location of maximum temperature. This ABS temperature profile alters the air-bearing pressure distribution, increasing the pressure at the hot NFT location compared with predictions of an isothermal air-bearing solver, so that the center of the pressure acting on the ABS is slightly closer to the trailing edge, thereby decreasing the pitch angle and increasing the minimum flying height. Other researchers have shown that the NFT’s thermal response time may be much faster than its protrusion response time (Xu et al. in IEEE Trans Magn 48:3280–3283, 2012). The slider’s dynamic response to a time-varying NFT thermal spot on the ABS while the combined TFC and NFT induced thermal protrusion remains constant is investigated with our dynamic air-bearing solver. We simulate the slider’s step response to a suddenly applied ABS temperature profile and a pulsed temperature profile that represents laser-on over data zones and laser-off over servo zones. The sudden (step) or rapid (pulse) increase in ABS temperature induces a sudden or rapid increase in pressure at the NFT location, thereby exciting the air bearing’s first pitch mode. For the slider design and simulation conditions used here, the result of the pitch mode excitation is to alter the position of the center of pressure in the slider’s length direction, thereby changing the pitch moment. In response, the pitch angle and minimum flying height change. The step response decays after approximately 0.15 ms. Because the laser duty cycle is much shorter than this response time, a periodic disturbance is predicted for the center of pressure coordinate, pitch angle, and minimum flying height. The peak-to-peak minimum flying height modulations are relatively small (only up to 0.126 nm); more significantly, the time-averaged minimum flying height increases 0.5 nm for the NFT that reached 208 °C compared to simulations of the isothermal ABS at ambient temperature. 相似文献
17.
It is a big challenge to determine ultra-low slider flying height accurately. The intensity interferometry flying height testing
method is widely used to determine slider flying height. However, the intrinsic measurement errors of the method are becoming
non-negligible with the decrease in slider flying height. Strategies have to be developed to minimize the errors. To measure
flying height with a normal incidence optical flying height tester, a calibration process is required to determine several
constants used in flying height calculation. In practice, the calibration is usually done simply by retracting the slider
from the disk and measuring the intensity minima and maxima of the interferogram during the retracting process. It has been
demonstrated that the single most important source of error in the flying height measurement is associated with errors in
the determination of the intensity maxima and minima. In this work, the effects of optical filter, the responding frequency
of photodetector, and the lack of the first order intensity minimum on the determination of the intensity maxima and minima
are studied. Methodologies to minimize the errors in flying height measurement caused by the above factors are developed. 相似文献
18.
The design of a head-disk interface for ultra-low flying height has been studied from the viewpoint of contact vibration. It is known that a super-smooth disk is necessary for a slider to fly at an ultra-low flying height; however, such a disk increases the friction force, which potentially increases the vibration of the slider. To solve this problem, the head-disk interface must be optimized to reduce this increased vibration. It has been shown that a large pitch angle and center-pad-mounted read/write elements have advantages in terms of slider/disk contact. It has also been found that a micro-texture on the air bearing surface can prevent contact vibration. Moreover, a frequency-shift-damping slider was found to damp the vibration effectively. To further investigate these findings, numerical simulation and modeling of slider dynamics during contact have been performed. Their results revealed two zones of contact vibration: a stable zone and an unstable zone. 相似文献