Stability Analysis of Grooved Journal Bearings in High-Speed Hard Disk Drive Considering Thermal Effect

2009 ◽  
Author(s):  
Honglai Li ◽  
Shuzhong Lin ◽  
Jing Wang ◽  
Zhiguo Zheng ◽  
Jintai Lin ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Thermal Effect ◽  
Hard Disk Drive ◽  
High Speed ◽  
Hard Disk ◽  
Disk Drive ◽  
Journal Bearings

Experimental Characterization Techniques for High Performance Hard Disk Drive Ball Bearing Spindle Motors

1999 ◽  
Author(s):  
Andrew Chong ◽  
Lu Yi ◽  
S. X. Chen ◽  
Q. D. Zhang
Keyword(s):  
Hard Disk Drive ◽  
High Speed ◽  
High Performance ◽  
Ball Bearing ◽  
Hard Disk ◽  
Disk Drive ◽  
Spindle Motor ◽  
Hard Disks ◽  
Steel Balls ◽  
Test Requirements

Abstract The key task for the spindle motor in a hard disk drive is to provide stable, reliable and consistent turning power for many years to allow the hard drive to function properly. As hard disks become more advanced, virtually every component in them is required to do more & perform better, and the spindle motor is no exception. Increasing the rotational speed at which the platters spin means that the data can be read off the disk faster, and also reduces rotational latency, the time that the heads must wait for the correct sector number to come under the head. For this reason, there has been a push to increase the speed of the spindle motor. Since the launching of hydro-dynamic bearing spindle technology for high speed application will not be in due course, current ball bearing technology will still be around for a couple of years provided the spindle speed does not exceed around 15 Krpm. Therefore optimizing the steel balls in the spindle system is an alternative to deal with the ever-increasing performance requirements of the hard disk drive. To accomplish this, we have to understand the failure phenomenon in the spindle, thereby set test requirements to overcome the failure mechanism. These test requirements will help us to understand the performance characteristic and robustness of the spindle motor. In this paper, the test requirements is set according to modal, load and vibration methods to quantify the hard disk drive ball bearing spindle motor.

Deformation of Hard Disk Drive Media Caused by Thermal Stress and Induced Air Flow

2014 ◽  
Vol 1061-1062 ◽  
pp. 866-873
Author(s):  
Pakornwit Padtha ◽  
Kiatfa Tangchaichit
Keyword(s):  
Thermal Stress ◽  
Hard Disk Drive ◽  
High Speed ◽  
Air Flow ◽  
Voice Coil Motor ◽  
Hard Disk ◽  
Disk Drive ◽  
Spindle Motor ◽  
High Rotational Speed ◽  
The Media

The spindle motor in a hard disk drive spins at a high rotational speed. These rotations generate air flow and thermal stress. Air flow is induced by the surface roughness of the media that is moving at a high speed through air. This air passes over the surface of many parts in the drive, including the media. Thermal stress is generated by heat in the parts, e.g. voice coil motor, pre-amplifier, slider pole tips, which are heated by electric power and by the spinning of the spindle motor. The air flow and thermal stress cause a change in the media shape called deformation.Simulation results show the trend of deformation has more bending when the slider moves outward from the media axis. The pressure acted more on the underside than on the upper side which caused the media to bend up to the top cover side of hard disk drive. The maximum deformation, 15 μm, occurred at the rim of media while the distance between the media and the slider is 30 μm; thus they did not contact each other.

The dimensional effects of windowing on crosstalk for high speed hard disk drive interconnects

2013 ◽  
Vol 24 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Krisada Prachumrasee ◽  
Arkom Kaewrawang ◽  
Apirat Siritaratiwat ◽  
Roong Sivaratana ◽  
Anan Kruesubthaworn
Keyword(s):  
Hard Disk Drive ◽  
High Speed ◽  
Hard Disk ◽  
Disk Drive ◽  
Dimensional Effects

A Method to Reduce Calculation Time for a Study of a Damper Plate in a High Speed Hard Disk Drive Simulation

2013 ◽  
Vol 423-426 ◽  
pp. 1940-1943 ◽  
Author(s):  
Jarupol Suriyawanakul ◽  
Kiatfa Tangchaichit
Keyword(s):  
Hard Disk Drive ◽  
High Speed ◽  
Computing Time ◽  
Hard Disk ◽  
Disk Drive ◽  
Computational Domain ◽  
Hexahedral Mesh ◽  
Design Work ◽  
Future Design ◽  
Eddy Simulation

The damper plate effect in a hard disk drive is studied using computational fluid dynamics technique. The well known Large Eddy Simulation technique needs high resources for computing power and time. This study presents a steady k-e turbulent model which needs lower resources but can predict the flow effect. The 3.5 inch hard disk drive is modeled with a hexahedral mesh for the computational domain. First, the RMS velocities of the model without damper plate and head stack assembly compared with LES and the transient k-e method are less than 6 %. After that, the damper plate is inserted into the model and the RMS velocity is compared using 4 methods which are LES, transient k-e, steady-transient k-e and steady k-e respectively. The results of k-e are very close to each other. The RMS velocity errors compared with LES rises up to 12.35-13.20 percent in the middle diameter zone, where there is an effect from diverted flow. The steady k-e provides a good computing time with 20 min/100 iterations and can show the trend of the damper plate effect which can be used usefully in future design work for various variables.

scholarly journals Development of High Speed Head for Hard Disk Drive Using Electron Beam Tomography.

Materia Japan ◽  
2000 ◽  
Vol 39 (2) ◽  
pp. 175-177
Author(s):  
Kimio Nakamura ◽  
Hiroshi Suzuki ◽  
Hisashi Takano
Keyword(s):  
Electron Beam ◽  
Hard Disk Drive ◽  
High Speed ◽  
Hard Disk ◽  
Disk Drive ◽  
Electron Beam Tomography

Decreasing Airflow Velocity in High Speed Hard Disk Drive by Using Spoiler

2014 ◽  
Vol 1061-1062 ◽  
pp. 862-865 ◽  
Author(s):  
Waranya Kankaew ◽  
Kiatfa Tangchaichit ◽  
Jarupol Suriyawanakul
Keyword(s):  
Hard Disk Drive ◽  
Computational Fluid Dynamic ◽  
Rotational Speed ◽  
High Speed ◽  
Fluid Dynamic ◽  
Hard Disk ◽  
Disk Drive ◽  
Airflow Velocity ◽  
Commercial Software ◽  
Airflow Simulation

This research aims at presenting the airflow simulation within the high speed Hard Disk Drive by installing the device called Spoiler which helps to reduce the airflow velocity before colliding with the read/write head. Due to the high speed airflow within the hard disk drive, it directly impacts on the vibration of the read/write arm and consequently causing the damage and inaccuracy function of the read/write head. The rotational speed of the platter is specified at 20,000 rpm (round per minute). According to this study, the length of Spoiler is divided into 4 values which are 15, 20, 25 and 30 millimeters respectively. Thereafter, apply each length of the Spoiler to the commercial software called Computational Fluid Dynamic (CFD) by using K-epsilon model. The result shows that the length of Spoiler at 30 millimeters can reduce the average airflow velocity by 57.18%.

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