Stress and Vibration Analysis of Motor Back Plate in HDD

2011 ◽  
Vol 275 ◽  
pp. 97-100 ◽  
Author(s):  
Geun Sub Heo ◽  
Oh Hyun Kang ◽  
Cheol Woo Park ◽  
Sang Ryong Lee ◽  
Choon Young Lee
Keyword(s):  
Resonant Frequency ◽  
High Speed ◽  
Vibration Mode ◽  
Hard Disk Drives ◽  
Mode Analysis ◽  
Design Parameters ◽  
Disk Drives ◽  
Ansys Software ◽  
Back Plate ◽  
Plate Shape

In the present study, we have simulated stress characteristics and vibration modes in the back plate of head-stack driving motor of 2.5 inch small sized hard disk drives (HDDs). The magnets in head-stack driving motor have large magnetic fields, and therefore, the resulting large force may induce fracture and deformation in the back plate of the motor. Since the high-speed motion of head-stack motor generates high frequency vibration, we analyzed the vibration mode to avoid resonant frequency. ANSYS software was used in this study to check the deformation of back plate with the following design parameters: thickness of plate, the number of support beams, and the width of support beams. From the vibration mode analysis, we obtained a stable plate shape whose operating frequency is off the resonant frequency.

The Theory Based on the Displacement of Mass of MEMS Gyroscope Used in Spinning Projectiles Analysis and Simulation

2011 ◽  
Vol 291-294 ◽  
pp. 3139-3143
Author(s):  
Xing Cui ◽  
Xiao Ming Zhang ◽  
Guo Bin Chen ◽  
Yong Hui Li ◽  
Jun Liu
Keyword(s):  
Angular Velocity ◽  
Kinetic Parameters ◽  
High Speed ◽  
Vibration Mode ◽  
Single Chip ◽  
Ansys Software ◽  
Mems Gyroscope ◽  
Harmonic Response ◽  
Structural Principle ◽  
The Difference

The MEMS gyroscope used in Spinning Projectiles is a single-chip and axis gyroscope drive by high-speed rotary of Spinning Projectiles. To analysis this theory, a corresponding mathematical module was established based on the structural principle of the gyroscope and the Kinetic parameters included in the mathematical module was analyzed and calculation. By calculation, the paper had drawn the curve between the displacement of mass and the input angular velocity. By using ANSYS software the vibration mode and harmonic response have been done, after comparing the results of imitation and calculation, it is found that the difference is little, so the theory based on the displacement of mass is correct.

Focusing Actuator for Magneto-optical Disk Drives

1993 ◽  
Vol 5 (4) ◽  
pp. 326-331
Author(s):  
Junichi Ichihara ◽  
◽  
Koichi Tezuka ◽  
Akihiko Makita
Keyword(s):  
High Speed ◽  
Hard Disk Drives ◽  
Higher Order ◽  
Optical Disk ◽  
Leaf Spring ◽  
Disk Drives ◽  
Mechanical Resonance ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
And Performance

Magneto-optical disk drives have some disadvantages compared with hard disk drives such as low access speed and low data rate. A small-light optical head and high speed rotation of the drive would improve the performance , as well as achieving over write. This paper details the development of a small-light focusing actuator, which can be used in high speed rotation of disks and make optical heads small and thin. It discusses the actuator suspension which raises the frequencies of higher order mechanical resonance. It also includes a parallel leaf spring suspension with the visco-elastic damping layer. It experimentally evaluates the vibration characteristics. Results show that the frequencies of higher order mechanical resonance are above 50kHz. The actuator is driven by a novel moving coil motor which makes the moving part thin and stiff. This paper describes the design and performance of the motor.

scholarly journals A Micro-Scaled Graphene Based Tree-Shaped Wideband Printed MIMO Antenna For Terahertz Applications

2021 ◽  
Author(s):  
K. Vasu Babu ◽  
Sudipta Das ◽  
Gaurav Varshney ◽  
Gorre Naga Jyothi S ◽  
Boddapati Taraka Phani Madhav
Keyword(s):  
Resonant Frequency ◽  
High Speed ◽  
Chemical Potential ◽  
Surface Current ◽  
Design Parameters ◽  
Impedance Bandwidth ◽  
Mimo Antenna ◽  
Design Evolution ◽  
Terahertz Applications ◽  
Distance Communication

Abstract A tree-shaped graphene based microstrip MIMO antenna for terahertz applications is proposed. The proposed MIMO antenna is designed on a 600×300 µm2 polyimide substrate. The designed MIMO antenna exhibits a wide impedance bandwidth of 88.14% (0.276–0.711 THz) due to the suggested modifications in the antenna configuration. The MIMO design parameters like total active reflection coefficient (TARC), mean effective gain (MEG), envelope correlation coefficient (ECC) and diversity gain (DG), Channel capacity loss (CCL) are evaluated and their values are found within acceptable limits. The proposed MIMO structure offers MEG ≤ -3.0 dB, TARC≤ -10.0 dB, DG≈ 10 dB, CCL < 0.5 bps/Hz/sec and ECC < 0.01 at the resonant frequency. At the resonant frequency, the isolation between the radiating elements of the proposed MIMO is recorded as -52 dB. The variations in operating frequency and S-parameters are also analyzed as a function of the chemical potential (µc) of the graphene material. The parametric analysis, structural design evolution steps, surface current distribution, antenna characteristics parameters and diversity parameters are discussed in detail in this paper. The designed MIMO antenna is suitable for high speed short distance communication, video rate imaging, biomedical imaging, sensing, and security scanning in the THz frequency band.

On the quasi-rigid body motion of the head actuator assembly in hard disk drives

2002 ◽  
Vol 216 (12) ◽  
pp. 1259-1262
Author(s):  
S Zeng
Keyword(s):  
Rigid Body ◽  
Vibration Mode ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Areal Density ◽  
Body Motion ◽  
Fe Model ◽  
Disk Drives ◽  
Rigid Body Mode ◽  
Set Up

A quasi-rigid (QR) vibration mode between 3 and 5 kHz is common in current hard disk drives (HDDs), which hinders servo bandwidth improvement and thus limits growth in the areal density (numbers of bits that can be stored per unit area) of HDDs. In this paper, a finite element (FE) model of a head actuator assembly (HAA) is developed and an experimental set-up is established to study the quasi-rigid body mode. The FE model result is compared with the experimental data. It is found that the quasi-rigid body mode is in fact a butterfly-like mode, which integrates the flexibility of the pivot assembly as well as the flexibility and the mass of the whole head actuator body.

Experimental Study on Flow-Induced Disk Flutter Dynamics by Measuring the Pressure Between Disks

2006 ◽  
Vol 129 (3) ◽  
pp. 368-375 ◽  
Author(s):  
Shigenori Takada ◽  
Norio Tagawa ◽  
Atsunobu Mori ◽  
Yoshiaki Mizoh ◽  
Masaru Nakakita
Keyword(s):  
Pressure Fluctuation ◽  
High Speed ◽  
Static Pressure ◽  
Dynamic Pressure ◽  
Hard Disk Drives ◽  
Laser Doppler Vibrometer ◽  
Disk Drives ◽  
Flow Induced Vibrations ◽  
The Mean ◽  
Disk Flutter

It is important to clarify the characteristics of flow-induced vibrations in hard disk drives in order to achieve an ultrahigh magnetic recording density. In particular, it is necessary to reduce the flow-induced disk vibrations referred to as disk flutter. This paper describes the correlation between the disk vibration amplitude and the pressure fluctuation between a pair of high-speed corotating disks. It also reveals the effects of the arm thickness and arm shape on the disk vibrations and the static pressure between the disks. The disk vibrations were measured using a laser Doppler vibrometer (LDV). The static pressure downstream of the arm between a pair of narrow disks was measured by a method in which a side-hole needle was used as a measurement probe. In addition, the direction of air flow along the trailing edge of the arm was measured using a hot-wire anemometer. The experimental results revealed that the arm inserted between the disks suppresses the disk vibrations. However, the shape and thickness of the arm did not quantitatively affect the disk vibrations. The root-mean-square (RMS) static pressure fluctuation downstream of the arm decreased remarkably, whereas the mean static pressure increased when the arm was inserted between the disks. Furthermore, the circumferential variations in both the RMS and mean static pressures reduced when the arm was inserted. Therefore, it is suggested that the disk vibrations are excited by an increase in the static pressure fluctuation, mean dynamic pressure, and circumferential variation in the static pressure between the disks. Consequently, the disk vibrations can be suppressed by inserting the arm or a spoiler.

scholarly journals Optimum Design of Oil Lubricated Thrust Bearing for Hard Disk Drive with High Speed Spindle Motor

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Yuta Sunami ◽  
Mohd Danial Ibrahim ◽  
Hiromu Hashimoto
Keyword(s):  
High Speed ◽  
Thrust Bearing ◽  
Dynamic Stiffness ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Optimization Method ◽  
Spindle Motor ◽  
Disk Drives ◽  
Thrust Bearings

This paper presents the application of optimization method developed by Hashimoto to design oil lubricated thrust bearings for 2.5 inch form factor hard disk drives (HDD). The designing involves optimization of groove geometry and dimensions. Calculations are carried out to maximize the dynamic stiffness of the thrust bearing spindle motor. Static and dynamic characteristics of the modeled thrust bearing are calculated using the divergence formulation method. Results show that, by using the proposed optimization method, dynamic stiffness values can be well improved with the bearing geometries not being fixed to conventional grooves.

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