• Journal of the Korean Society for Precision Engineering
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• v.15 no.3
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• pp.11-17
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• 1998

The mecanum wheel was originaly developed in sweden to realize the omni-directional motion of the cart. The circumference of each wheel is lined with rollers set at 45 degrees relative to the main wheel. This paper proves that the roller of the mecanum wheel shapes the ellipsoid, derives the kinematic relationships between the parameters of the wheel and rollers, and proposes the procedure to determine the parameters of the wheel. The result was implemented into the computer program for the design of the mecanum wheel.

• Journal of Sericultural and Entomological Science
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• v.23 no.2
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• pp.55-58
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• 1982

This survey was carried out at the Sericultural Experiment Station. Suweon to clarify the kinds of leaf rollers damaging mulberry leaves and determine the dominant species of them. The results obtained are as follow: 1. A total of seven species including 2 unrecorded species, Olethreutes hemiplaca MAYRICK. and Olethreutes doubledayana BARRET, were found as mulberry attacking leaf rollers. 2. The dominant species of mulberry leaf rollers in Korea was identified as O. hemiplaca M. followed by Adoxophyes orana B.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.743-750
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• 2016

Track rollers are the key parts that support the weight applied to the caterpillar track of construction machinery. The operating conditions of construction machinery are harsh; hence, the track rollers exposed to these conditions can experience failures such as oil leakage and breakdown of the machine, because of impacts during driving. The failure of track-rollers has a major effect on the operation of the construction machinery. Therefore, each manufacturer tries to evaluate the performance of their products by conducting a self-test. However, only the vertical loads applied to the track rollers are considered in most of the self-tests. This method has the problem of ignoring the horizontal loads that are applied to the track rollers while rotary driving, and hence it does not create the practical operating condition of the construction machinery. In this study, we have determined the experimental conditions that effectively consider the magnitudes of the vertical and horizontal loads. The results of simulations and experiments conducted to assess the influence of horizontal loads on the failure of track rollers are presented in this paper.

• Journal of the Korean Institute of Gas
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• v.19 no.4
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• pp.55-61
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• 2015

In this paper, the displacement behavior characteristic of hollow rollers with various cross sectional area profiles and circular plate for load supporting capacity increment has been presented using a finite element method. The FEM results present that the hollow roller with X-shaped or Y-shaped columns between outer tube, middle tube and inner tube reduces a maximum displacement at the middle length of hollow rollers. And the circular plate, which is inserted at the middle of the hollow roller, is very useful to reduce the maximum displacement of hollow rollers with the plate thickness of 30~40mm. This paper presents the weight vs the maximum displacement ratio in which is represented for the optimized design as a function of a hollow roller total weight. The FEM analyzed results recommend the design model 4, 5 and 6 of hollow rollers for decreasing the ratio of maximum displacement and total weight of hollow rollers.

• Journal of Ocean Engineering and Technology
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• v.16 no.2
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• pp.38-43
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• 2002

Die-less forming is a cold forming process which is to bend thick flat plates into compound curved plates using two asymmetric rollers. This forming method has several advantages compared with line heating which is widely used to fabricate compound curved pieces in shipyards. The die-less forming, however, has scarcely been studied. Even the deformation mechanism in this forming process has not been understood clearly. So, in this paper, the deformation characteristics of die-less forming is investigated analytically and numerically. for the analytic investigation, slab method based on equilibrium equation is applied. And the mechanism of curvature generation is derived for the asymmetry in roller applied. And three dimensional numerical analyses are performed with realistic modeling of interactions between the rollers and work-piece using finite element program, ABAQUS. It is shown that curvature generation is mainly due to the difference of normal positive strain distribution between the top and bottom surface of the work-piece. And a convex-type curved plate is formed if the center region of the work-piece is rolled with asymmetric rollers of which the lower is larger than the upper in diameter.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.11
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• pp.911-918
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• 2016

A conical roll-shaping process was proposed for fabrication of a metallic spiral blade applied to a small-scale wind turbine system. A spiral blade has continuously different curvatures, with a range of 100 to 350 mm radius. To fabricate this complex shape, we developed a conical roll-shaping process having two main conical rollers for feeding a blank sheet, and two cylindrical side rollers for control of local bending. For clear understanding of the process parameters, numerical analyses were conducted using a commercial code, Pam-Stamp. This study optimized the effects of process parameters, such as gap and angle between the main rollers and side rollers, and also the movement of side rollers. In order to increase the forming efficiency, a central rotation point was also calculated by the analytical approach. This developed rolling process can thus be utilized in a sheet metal forming process for obtaining spirally curved sheet metal shapes.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.291-292
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• 2002

Using a low viscosity synthetic traction oil and a low viscosity mineral oil with nearly equal viscosity grade of ISO VG 32, the effect of kind of oil on the fatigue life of bearing steel rollers was examined. A pair of rollers finished the contact surfaces to a mirror-like condition were driven under rolling with sliding conditions of s = -3.2% and a maximum Hertzian stress in the range of $P_H=2.8GPa{\sim}4.0GPa$ was applied in point contact condition. As a result of experiments, the fatigue life with a mineral oil was longer than that with a traction oil under higher stress conditions above $P_H=3.4GPa$. Based on the numerical calculation results of the thermal EHL which simulates the present experiment, the authors discuss the reason why such a difference in the fatigue life comes out.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.803-810
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• 2000

Red pepper powder is produced from dried red pepper through milling process with roller mill. Traditional Roller mill is convenient for crushing wax and fiber parts in red pepper. However, some metallics are produced by the friction of two rollers when it operates without feeding of red peppers. In order to reduce this metallic problems created in the roller mill in the process of red pepper, a new roller mill mechanism which enables two roller to apart when red pepper is not fed between two rollers was introduced. Adjustment of clearance between two rollers was able to conducted by the current difference between idling and crushing process. Two types of roller surface, grove and flat, and two different roller mills, cast iron and Ti coating, are tested and compared in this experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1262-1265
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• 2004

A cycloidal speed reducer is a type of the speed reducers of machinery. The cycloidal speed reducer consists of two cycloidal plate gears, housing roller gear, input shaft, output pin and shaft, and eccentric bearings. Especially the cycloidal plate gear has the peculiar parts of the teeth, because of gearing with the housing roller gear that has the several rollers on the circular line. And then all teeth on the cycloidal plate gear can be designed to contact with the rollers on the housing roller gear at the same time. Therefore the cycloidal plate gear has always contact motion with rollers and the force is interacted between roller gear with cycloidal plate gear. Because the contact force and friction force must be required to improve the accuracy in design procedures of cycloidal speed reducers, this paper presents a force analysis considered friction effect approach derived by static force equilibrium condition, geometrical adaptation, instant velocity center method and relative velocity method.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.39-43
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• 2012

This paper presents a study on the design of a pulling module for silicon ingot and an apparatus of manufacturing silicon single crystal ingot using the same method. The pulling module is conceptually designed by using TRIZ. Czochralski method(CZ) is representative way to manufacture single crystal ingot for wafers. The seed can be broken by high tension which is caused by large weight of a silicon ingot. The solution of this problem has been derived using 6SC(6 steps creativity)TRIZ. The pulling module is actuated by DC motor and rollers. High tension in the seed is removed by the rotate-elevate motion of rollers in the pulling module. A rubber belt is included in the rotate-elevate mechanism for increasing friction between rollers and silicon ingot.