Novi, MI, United States
Novi, MI, United States

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Ashida Y.,NHK International Corporation
NACE - International Corrosion Conference Series | Year: 2016

This study focuses on a better understanding of significant pitting corrosion on coating surface damaged carbon steels, or low alloy steels, during salt spray testing for automotive applications. Anodic cyclic polarization test was used to evaluate the severity of pitting corrosion, and to estimate the corrosion rate of raw materials. Corrosion potential Ecorr, pitting potential Epit, and pitting protection potential Epp were measured by conducting anodic cyclic potentiodynamic polarization (CPP) on 3 carbon steels. The scattering of the three potentials were observed within 35 mV on a 1 cm2 exposure surface of the 3 steels. To simulate the surface damage on automobile suspension coil springs and stabilizer bars, gravel shocking and a hardness indenter were used to generate damage on ZnP pretreated and coated shot peening surfaces. The corrosion potential evolution of steel substrate, ZnP pretreated surface, and damaged coating surface were monitored in 5% NaCI solution for 72 hours. The timing of pretreatment exposure and metal substrate exposure to the NaCI solution were noticeable. A pitting model and a correlation between pitting occurrence and fatigue cracking are further discussed. © 2016 by NACE International.


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.


Li L.,Harbin Institute of Technology | Li L.,University of California at San Diego | Zheng H.,University of California at San Diego | Fanslau E.B.,NHK International Corporation | Talke F.E.,University of California at San Diego
Microsystem Technologies | Year: 2011

A finite element (FE) model for the dimple/gimbal interface of a hard disk drive is developed as a function of normal load, friction coefficient, material properties and dimple geometry. The air bearing force is approximated as a normal load acting on the slider. A rotational acceleration was applied to the dimple to simulate accessing of a hard disk drive suspension during seeking. Results for the relative displacement between the dimple and the gimbal are determined for a typical suspension as a function of normal load, rotational acceleration, friction coefficient, material properties and geometrical parameters of suspension and flexure. © 2011 The Author(s).


Li L.,Harbin Institute of Technology | Li L.,University of California at San Diego | Fanslau E.,NHK International Corporation | Talke F.,University of California at San Diego
Microsystem Technologies | Year: 2011

The contact of the dimple/gimbal interface in a hard disk drive was studied experimentally. Two types of dimples with different surface roughness and several types of gimbal materials were investigated. The load-displacement curves for the contact of the dimple and the gimbal exhibit hysteresis, which is related to the plastic deformation of the asperities, during the first few load/unload cycles. The roughness of dimple and gimbal samples was measured before and after load-unload testing using an AFM. The plasticity index was determined based on the roughness measurement. The results show that the roughness and plasticity index of the non-polished dimple decrease with the number of load/unload cycles significantly, i.e., the contact surface becomes smoother than the original surface due to plastic deformation. The roughness and plasticity index of the laser-polished dimple change slightly before and after the load-unload test. © 2011 The Author(s).


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.


Patent
Nhk International Corporation and Nhk Spring Co. | Date: 2015-02-12

A coil spring modeling apparatus includes an actuator unit formed of a Stewart-platform-type parallel mechanism, a first inner load cell accommodated in a first attachment member, a second inner load cell accommodated in a second attachment member, and a rotation support mechanism. The actuator unit is rotatably supported by the rotation support mechanism about an axis. The first inner load cell is arranged on the first seat adapter coaxially with the rotation support mechanism, and detects an axial force acting on the lower spring seat and a moment. The second inner load cell is arranged under the second seat adapter coaxially with the rotation support mechanism, and detects an axial force acting on the upper spring seat and a moment.


Patent
Nhk International Corporation and Nhk Spring Co. | Date: 2015-02-12

A coil spring modeling apparatus includes a first attachment member disposed on a lower spring seat, a second attachment member disposed on an upper spring seat, an actuator unit formed of a Stewart-platform-type parallel mechanism, a hydraulic pressure supply device, a torsion detection mechanism, and a controller. The torsion detection mechanism is constituted of displacement gauges such as a linear variable differential transformer. The displacement gauges are provided on hydraulic cylinders, and detect amounts of displacement relative to the reference lengths of the hydraulic cylinders, respectively. The controller calculates a relative torsional angle between the first attachment member and the second attachment member based on the detected displacement.


Patent
Nhk Spring Co. and Nhk International Corporation | Date: 2015-02-12

A coil spring modeling apparatus includes a first attachment member disposed on a lower spring seat, a second attachment member disposed on an upper spring seat, an actuator unit formed of a Stewart-platform-type parallel mechanism, a spring height detection mechanism, and a controller. The spring height detection mechanism is constituted of displacement gauges such as a linear variable differential transformer. These gauges are provided on hydraulic cylinders, and detect amounts of displacement relative to the reference lengths of the hydraulic cylinders, respectively. A hydraulic pressure supply device is controlled by the controller and supplies fluid pressure according to the displacement detected by the gauges to the respective hydraulic cylinders.


Patent
NHK Spring Co. and NHK International Corporation | Date: 2010-06-10

A stabilizer bar is intended for use in a vehicle, and a torsion part of the stabilizer bar is fixed to the vehicle body by a fixing member. A resin sheathing is provided integrally on an outer peripheral surface of the stabilizer bar. The fixing member is composed of the sheathing, a rubber bush disposed on the outer periphery of the sheathing, and a mounting fixture for mounting the rubber bush on the vehicle body side so as to cover the outer periphery of the rubber bush. The sheathing and the rubber bush are immovably assembled to each other. Thus, there may be provided a vehicle stabilizer, highly durable, easily mountable and replaceable, low-cost, and highly operable.


Patent
Nhk International Corporation and Nhk Spring Co. | Date: 2012-05-14

A stabilizer bar is intended for use in a vehicle, and a torsion part of the stabilizer bar is fixed to the vehicle body by a fixing member. A resin sheathing is provided integrally on an outer peripheral surface of the stabilizer bar. The fixing member is composed of the sheathing, a rubber bush disposed on the outer periphery of the sheathing, and a mounting fixture for mounting the rubber bush on the vehicle body side so as to cover the outer periphery of the rubber bush. The sheathing and the rubber bush are immovably assembled to each other. Thus, there may be provided a vehicle stabilizer, highly durable, easily mountable and replaceable, low-cost, and highly operable.

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