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Zheng H.,University of California at San Diego | Murthy A.N.,Hitachi GST Inc. | Fanslau Jr. E.B.,NHK International Corporation | Talke F.E.,University of California at San Diego
Microsystem Technologies | Year: 2010

Hard disk drives must be designed to be resistant to operational and non-operational shock (Jayson et al. in IEEE Trans Magn 38(5):2150-2152, 2002). Numerical and experimental results show that "lift-tab separation" and "dimple separation" are two possible failure modes of presently used head suspension assemblies (Murthy in Ph.D. thesis, Center for Magnetic Recording Research, University of California, San Diego, 2007). In addition, "dimple and tongue wear" at the interface of gimbal and dimple are areas of concern in the design and operation of high performance suspensions during shock. In this investigation, an improved numerical model for non-operational shock response of a load/unload hard disk drive is implemented by including design parameters of suspension such as dimple preload, suspension material, dimple height and the surface diameter of the dimple in the model. Results for dimple and lift-tab separation, as well as the maximum impact stress at the dimple region, as a function of preload and suspension design parameters, will be presented. Source


Nishizawa S.,NHK International Corporation | Nakamura T.,NHK SPRING CO. | Furukawa K.,NHK SPRING CO. | Moriyama S.,NHK SPRING CO. | Sato R.,NHK SPRING CO.
SAE International Journal of Passenger Cars - Mechanical Systems | Year: 2014

In McPherson strut applications for automotive suspension systems, the desired coil spring reaction force vector (FLP: force line position) that minimizes damper friction and king pin moment is typically determined by Statics/Kinematics calculations. There is not a device available on the open market today which can mimic the coil spring reaction force vector within the suspension system. Such a programmable coil spring reaction force vector generator, named "Universal Spring", was developed in 2003 (USPG2003), and was then improved in 2013 (USPG2013) from the standpoint of accuracy, durability and reliability. The device is actuated by six hydraulic cylinders constructing a Stewart platform type parallel mechanism. Accuracy of FLP generated by USPG2013 is 1.1mm at maximum in φ{symbol}80mm area around strut axis. Using this modified device, the relationship between the spring reaction force vector and damper friction, as well as spring reaction force vector and king pin moment, can be experimentally studied to confirm vehicle characteristics without actually producing any prototype coil springs. These studies will be discussed in this paper with showing actual measured data. Furthermore, it was found that approximately 70% of moment generated by upper bearing friction was transferred to king pin moment for the suspension system used in this experiment. The validity of this device was proven by comparing to actual coil spring based testing data. Copyright © 2014 SAE International. Source


Raeymaekers B.,University of California at San Diego | Helm S.,University of California at San Diego | Brunner R.,University of California at San Diego | Fanslau E.B.,NHK International Corporation | Talke F.E.,University of California at San Diego
Wear | Year: 2010

Fretting wear of the dimple/gimbal interface in a hard disk drive suspension is investigated. The energy dissipated between the dimple and the gimbal spring is determined as a function of operating conditions and material properties, and related to the wear observed at the interface. Abrasive, adhesive and tribo-chemical wear are found to be present. A thin film of gold on the gimbal resulted in the best wear behavior. © 2010 Elsevier B.V. All rights reserved. Source


Raeymaekers B.,University of California at San Diego | Helm S.,University of California at San Diego | Brunner R.,University of California at San Diego | Fanslau E.B.,NHK International Corporation | Talke F.E.,University of California at San Diego
Proceedings of the ASME/STLE International Joint Tribology Conference 2009, IJTC2009 | Year: 2010

Wear particles in a hard disk drive may cause the head/disk interface to fail. We have experimentally investigated wear particle generation resulting from fretting wear between the dimple on the suspension and the gimbal spring. We have found that increasing the normal load as well as using a low friction coating reduces the formation of wear particles. Copyright © 2009 by ASME. Source


Tang Z.,South China University of Technology | Tang Z.,University of California at San Diego | Salas Mendez P.A.,University of California at San Diego | Hogan J.,NHK International Corporation | Talke F.E.,University of California at San Diego
Microsystem Technologies | Year: 2013

A dynamic simulation is performed to investigate contact and friction forces at the dimple/gimbal interface. The time history of slider motion, the resultant force as well as the pitch and roll moments acting on the slider are determined. The time-dependent contact and friction forces at the dimple/gimbal interface are obtained. The effect of material properties on contact and friction forces at the dimple/gimbal interface is investigated. Experimental results for touch-down and take-off characteristics are presented. © 2013 Springer-Verlag Berlin Heidelberg. Source

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