• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.97-103
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• 2008

In general, the strength of gears is calculated using the formula of AGMA or JGMA. But these formula can not be applied directly to the strength calculation of the rack and pinion of steering gear assay, because of complex tooth and contact shapes. So Lewis bending stress and Hertzian contact stress formula are generally used for the design of rack and pinion of steering gear assay. But these formula do not also give the exact stress of rack and pinion. In this paper, comparing the finite element analysis results and the experimentally measured values, it is shown that the finite element modeling technique of the rack and pinion of steering assay is reasonable.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.43-53
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• 1998

This paper addresses an optimization for reducing a steering error of a rack-and-pinion steering linkage with a MacPherson strut independent front suspension system. The length, orientations and inner joint positions of a tie-rod are selected as design variables and Ackerman geonetry, understeer effect, minimum turn radius, wheel alignment and packaging are considered as design constraints. Nonlinear kinematic analysis of the steering system is performed for calculating the values of cost and constraints, and Augmented Lagrange Multiplier(ALM) method is used for solving the constrained optinization problem. The optimization results show that the steering error are considerably reduced while satisfying all the constraints.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.3
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• pp.40-49
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• 1996

The problem related to the rotational vibration at steering wheel end of passenger cars during high speed driving is investigated. to analyze vibration of steering wheel, a steering system of passenger car is modelled in twelve degrees of freedom including backlash effect of rack and pinion gear system. The one degree of freedom system with backlash in investigated by the analytical method. Consequently the skeleton curve and the frequency response curves are computed. The steering system is analyzed by the numerical simulation using the 4th order Runge-Kutta method, the obtained results are compared with the experimental data. Also the effects of the change of rack gear tooth stiffness and backlash on the acceleration level of steering wheel are investigated. As a result, it can be found that the acceleration level of steering wheel becames lower as the rack gear tooth stiffness becames higher, and that acceleration level becames high as the magnitude of backlash between rack and pinion gear increase.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.214-221
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• 1999

In this research, a power-assisted steering system is modeled as a part of a full vehicle dynamic model. The dynamic model of the steering system incorporates hydraulic and dynamic relations between major parts of a steering system, such as steering column, control valve, rack and pinion gear. Through an experimental setup of the steering system, the steering system model is validated. The steering model is included in a full vehicle dynamic model of a car, where kinematic relations between steering and suspension system are defined, and various simulations are performed to evaluate the performance of steering system in conjunction with overall dynamic performance of the vehicle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.747-748
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• 2008

• Tribology and Lubricants
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• v.26 no.1
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• pp.61-67
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• 2010

The purpose of this paper is to study and analyze the failure examples on tribological characteristics of an automotive steering system. In this failure study, the grease leakage may stick leaked grease, dust, and wear particles between pinion and rack gears in mechanical steering system. In the case of seal failures such as a rod seal, o-ring and oil seals, the gear box and oil pump do not operate properly due to lack of oils. This means that oil pump does not supply a working fluid and produce a normal oil pressure of the steering system. This leads to leak a working fluid from the seals and produce a wear between pinion and rack gears. Especially, the leaked oil is usually mixed with internal wear particles and foreign dust/fine sands. Thus no leakage of working oils is very important design concepts, which is strongly related to the sealing components and smoothly operating of the mechanical friction parts of power steering system.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.127-134
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• 2002

This study present a direct steering system using rack and pinion for ultra-small vehicles. The traditional small vehicles for special use had the limitation of space by reason of short wheel tread. These vehicles has adopted a indirect steering system or a center arm system for steering. The disadvantages of these system were deterioration of gear efficiency and increase of parts. For direct-linkage to both knuckles, steering system is made up of out-side tie rods, tie-rod ends, and gear box. Thus, the proposed system has a minimum number of parts. The experimental results show a maximum efficiency at minimum steering angle and a minimum clearance circle. These effects were accomplished by adopting a Ackerman-Jantaud theory.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10b
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• pp.59-62
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• 2003

The precision cold forging of helical gear for steering pinion has been studied. Because of the large helix angle, there are many difficult problems to control the material flow and part dimension. The die shape was proposed to improve the flow of workpiece. In order to improve the dimensional accuracy of forged part, a FE analysis was performed. The proposed die shape drives to flow amicably workpiece. The applied load was reduced up to 10 percent, compared to the conventional-shaped-die. The elastic deformation of die has been investigated quantitatively by the 3-dimensional FE analysis. The die-land has been expanded up to $10{\mu}m$ on loading stage, based on the FEM results. Therefore, the elastic deformation amounts should be taken into consideration to improve the dimensional accuracy of forged helical gear.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.39-47
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• 1997

The focus of this research is to set up and describe the mathematical derivation of an automobile power-assisted rack and pinion steering system dynamics. The mathematical model of the power steering system dynamics with a 5 DOF linear vehicle model will be used in the computer simulation and evaluated comparing with the experimental results. This model is flexible to accommodate different vehicles through simple parameter changes. The developed mathematical model will attempt to provide enhanced driver realism to a Systems Technology, Inc. driving SIMulator(STISIM).

• Transactions of Materials Processing
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• v.32 no.6
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• pp.376-383
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• 2023

The torsion bar, which is a steering torque sensor, is mounted between the steering pinion and the input shaft in the IPA(input pinion assembly). Accurate torque measurement is important to improve the sense of operation, and the straightness of the torsion bar can affect torque measurement. In this study, the amount of bending was measured and the exact shape was analyzed regarding the bending phenomenon in the press-fitting process for torsion bars. The effect of alignment error was analyzed through finite element forming analysis. Process data analysis was conducted for the double-end press fit model. If there is an alignment error of about 10% of the serration tooth height, the indentation load is reduced by about 10%. If there is an alignment error, the torsion bar is rotated.