• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.344-349
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• 2005

This paper presents a geometrical error analysis of wheel curve generation method for micro aspheric surface machining using parallel grinding method. In aspheric grinding, wheel wear in process is crucial parameter for profile error of the ground surface. To decrease wheel weal parallel grinding method is adopted. Wheel and work piece (Tungsten carbide) contact point changes during machining process. In truing process of the wheel radius is determined by the angle and distance between wheel and truer. Wheel radius error is predominantly affected by vertical deviation between the wheel rotation center and the truer center Simulation for vertical error and wheel radius error shows same tendency that expected by geometrical analysis. Experimental results show that the analysis of curve generation method matches with simulations and wheel radius errors.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.81-86
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• 2005

The agricultural working tractor of this study is equipped with 4 wheel driving system developed in study 1 and 4-type wheel steering system. The wheel steering system has four type of steering methods that are front wheel steering, rear wheel steering, 4 wheel steering with opposite phase, and 4 wheel steering with corresponding phase. This study introduces the hydraulic circuit of the 4-type wheel steering system and the construction of working tractor. Judging from the field test results of the developed working tractor, it is apparent that 4-type wheel steering system has many advantages when driving in a narrow corral.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.854-859
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• 2008

In a railway vehicle, contact between wheel and rail is a peculiar characteristic and variations of wheel and rail profile influence on the dynamic characteristics of railway vehicle. Thus the variations of the wheel and rail profile are very important in railway dynamics. Recently a research relating to active steering to improve the curving performance of vehicle is progressing actively at home and abroad. In this field, a pre-study for the wheel/rail contact geometry is needed and especially the variation of the wheel/rail contact geometry with wheel wear is the key design parameter to develop the controller of the active steering bogie. In this paper, we have experimentally studied to analyze the variation of the wheel/rail contact geometry with wheel wear as a pre-study to develop the active steering bogie for electric multiple unit (EMU). For this, we have made an experiment with EMU operating in curving area. We have measured the wear profiles of the wheel of the test vehicle and analyzed the wheel/rail contact geometry with a mileage of the test vehicle. In experiment with test vehicle, we have got the useful data to design the steering controller of the wheelset.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.656-662
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• 2003

The rolling-stocks used in conventional line have suffered wheel problems due to lack of adaptability with track. These brought out severe wheel wear and inefficiency of wheel maintenance. Especially, tight wheel maintenance criteria have caused waste factors of wheel machining, these increases rolling-stock maintenance costs. Thus, this study was started to Propose the wheel maintenance plans to improve maintenance efficiency in respect to wheel maintenance process in rolling-stock workshop. Here, we describe some results

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1868-1873
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• 2011

In this paper, a theoretical formulation of a simplified wheel-set model for collision-induced derailments was evaluated by numerical simulations for the wheel-climb derailment and wheel-lift derailment types. The derailment types were classified into the wheel-climb derailment and the wheel-lift derailment according to the friction force direction of the wheel-flange. The wheel-climb derailment type was classified into Climb-up, Climb/Roll-over, and Roll-over-C, and wheel-lift derailment type was classified into Slip-up, Slip/Roll-over and Roll-over-L. To verify the theoretical equations derived for the wheel-climb derailment and the wheel-lift derailment, dynamic simulations using RecurDyn of Functionbay and Ls-Dyna of LSTC were performed and compared for some examples. The derailment predictions of the suggested theoretical formulation were in good agreement with those of the numerical simulations. The direction of the frictional force between the wheel-flange and the rail can be well predicted using the suggested derailment formulation at a initial derailment.

• International Journal of Railway
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• v.1 no.2
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• pp.31-36
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• 2008

$DF_{21}$ diesel locomotive was designed to satisfy the requirement of Kunming Meter track and the 2Co self-guided radial bogie was used to suit the complex curve track. There are totally 12 locomotives was served on the track. The first two locomotives were devotion running on the track since April 2003, the wheel tread splling was occurred on the middle wheel set of the two locomotives after running nearly 150 thousands km on the track of the two locomotives at August 2004. The dynamic analysis was carried out to find the reason. The wheel set longitudinal vibration resonance phenomenon was existed on the locomotive dynamic performance, and this was caused by the too big longitudinal stiffness of the journal box bar on the middle wheel set. Wheel set longitudinal vibration resonance maybe an important reason of lead to wheel tread spalling. The corresponding mend methods were put forward from the point of view of wheel set longitudinal vibration resonance. All the wheel tread of the 12 locomotives on the middle wheel set were in good condition and not occurred the wheel tread spalling after the mend till December 2007 after 350 thousands km were finished. The mechanism of the wheel tread splling and corresponding mend method was discussed in detail in this paper.

• Journal of KSNVE
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• v.10 no.4
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• pp.629-635
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• 2000

Wheel /rail interaction has been known as a major source of railway noise. In this paper, a low noise wheel structure is developed and its effect on noise reduction is investigated. The developed low noise wheel employees a rubber material inserted into a steel rim or mounted on the wheel surface. Since the low noise wheel has low stiffness and high damping ratio compared to a solid wheel, the measurement results show that it reduces the rolling and squeal noise. It turns out that the proposed wheel could reduce interior noise level by 4∼5dB(A) and vehicle vibration level by 7∼10 dB. Although the proposed structure seems to be promising in noise reduction of railway vehicles, the low noise wheel is to be verified in endurance and cost effect.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.66-71
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• 2006

A geometric contact conditions of wheel/rail affect the dynamic behavior of rolling stock. Mechanical force acted on the wheel/rail causes excessive wear and increase the maintenance cost. In this study, we have studied the dynamic behavior of the urban railway vehicle with new and worn wheel by VAMPIRE program. And we have tested the accelerations of wheelset on the conventional line. The results of simulation are compared with the measuring data of field test. It shows that the acceleration of worn wheel is greater than the acceleration of new wheel in the straight track line but on the contrary, the acceleration of new wheel is greater than the acceleration of worn wheel in curved track. That results explain that the new wheel is worn out greater than the worn wheel in curved track line and need to be maintained more seriously when running in curved track line.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.291-298
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• 1998

The object of this study is to investigate the effect of elastic wheel from the viewpoint of noise and vibration of railway vehicle. The vibration reduction was predicted from the FRF difference between elastic wheel and solid wheel by FEM simulation. The elastic wheel and solid wheel were compared in viewpoint of carbody vibration and car interior noise level. The effect of elastic wheel on the noise and vibration of subway vehicle was obtained. But, the application of elastic wheel must be reviewed in some aspect.

• Journal of Biosystems Engineering
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• v.21 no.1
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• pp.34-43
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• 1996

The present pesticide application technology widely used with a power sprayer in Korea is assessed as the problem awaiting solution in the point of view of its ineffectiveness, inefficiency, and environmental contamination. As one approach to get rid of these problems, the boom spraying with ultra-low volume and precision application technology has been recommended. The study was undertaken to investigate plants damages incurred by the self-propelled boom-sprayer vehicle, to develop the design criteria of vehicle wheel, and to compare plant damages caused by the front wheel steering vehicle, the 4-wheel drive vehicle and the articulated vehicle, by the computer simulation. The experiment showed that the amount of damaged plants incurred by the self-propelled boom sprayer were about 0.29% in average in the field size of 100m$\times$50m(0.5ha), about 60~80% of which recovering while growing. The recommandable wheel size was analyzed to be 70~100cm in diameter, 8~15cm in width from the vehicle-plant-soil relationship. The simulation on damaged plants anticipated to be incurred by various steering vehicles showed that the smaller the turning radius, the lesser the damaged plants within its range of 3~5m. Average plant damage rate by the front wheel steering vehicle, the 4-wheel drive vehicle and articulated vehicle was relatively assessed to be 2 : 1.8 : 1.