• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.348-354
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• 2003

An analysis of the dynamic behavior between disk and roller has been performed when the torque is transmitted to toroidal IVT (Infinitely Variable Transmission). The contact area, shape and pressure with elliptical shapes between disk and roller are computed as the transmission ratios are changed. This study will give the information of contact shapes between roller-input dist and roller-output disk which are working under the most severe condition. The computed results are expected to guide the design criteria for the enhanced endurance li(e. Furthermore, the investigation of contact behaviors is very crucial to develop the traction oil that the efficiency of IVT system is most dependent on.

• International Journal of Highway Engineering
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• v.3 no.4 s.10
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• pp.127-136
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• 2001

To increase the structural integrity of concrete box culvert good compaction by the dynamic compaction roller with bi9 capacity is as effective as good backfill materials. It is needed for effective compaction that a compaction roller closes to concrete structure with high frequency. However structural distress of the culvert could be occur due to the excessive earth pressure by great dynamic compaction load. To investigate the characteristics of Induced stress by compaction, a box culvert was constructed with changing cushion materials and compaction methods. Two types of cushion material such as tire rubber chip and EPS(Expanded Polystyrene) were used as cushion panels and they are set on the culverts before backfill construction. Laboratory test result of cushion material says that the value of dynamic elastic modulus of rubber is lesser than that of EPS. On the other hand, material damping of rubber material is greater than that of EPS. In most case, dynamic compaction rollers with 10.5 ton weights were used and vibration frequency was applied 30Hz for the great compaction energy. This paper presents the main results on the characteristics of dynamic earth pressures during compaction. The amounts of induced dynamic pressures$(\Delta\sigma\;h)$ by compaction are affected with construction condition such as compaction frequency, depth of pressure cell, distance between roller and the wall of culvert and roller direction. Based on the measured values dynamic lateral pressure on the culverts, it could be said that orthogonal direction of roller to the length of culvert is more effective to compaction efficiency than parallel direction.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.1
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• pp.28-34
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• 2023

In the anchovy boat seine fishing boat, it is necessary to select other aquatic organisms other than live anchovies, which are the target species of catch. By making a rotating roller sorter using hydraulic pressure, the anchovy sorting amount was compared and the sorting accuracy of the rotary roller sorter, and the discharge speed of butter fish and jerry fish according to the number of roller revolutions were analyzed. The rotating roller sorter increases the weight of the sorted raw anchovy by 54%, 74% and 91.5% compared to the round bar fixed type, so it can reduce the required time by an average of 73.2%. As a result of converting the sorting accuracy to the weight of pure anchovies excluding the catch weight, the round bar fixed type was 89%; however, the average of the rotating roller sorter was 97.7%. Thus, the sorting accuracy of the rotary roller sorter was further improved by about 8.7%. The roller speed moved 7% at 300 rpm, 7.5% at 600 rpm, and 16% at 900 rpm, so butter fish were discharged overboard 10% faster than jelly fish on average. In addition, the average feed speed of butter fish and jelly fish is 1,400 mm/s when the roller rotation speed is 300 rpm, 1,480 mm/s at 600 rpm, and 1,850 mm/s at 900 rpm. A Φ58 mm roller rotates once it moved about 1.23 mm. In the future, a follow-up study of quantitative evaluation is needed targeting more non-target fish species of anchovy boat seine.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1975-1981
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• 1991

A new numerical solution of the elastohydrodynamic lubrication(EHL) problem of an axially profiled cylindrical roller is presented. A finite difference method and the Newton-Raphson method are used to solve the nonlinear system equations. A non-uniform grid system is adopted to reduce the number of grid points and to obtain accurate solution. For two different types of profiles which have similar elastostatic pressure distribution, the EHL results show large differences. Especially the difference in film shape is larger than in pressure distribution. Therefore, the magnitude of the minimum film thickness should be a major criteria to design the axial profile of the roller. Variations of the minimum film thickness with dimensionless parameters show considerably different behavior from those of infinite solution and show a good agreement with the experimental data in literatures. Present numerical scheme can be used generally in the analysis of three-dimensional EHL problem.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.1
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• pp.137-146
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• 2008

Proper amount of entrained air and nip force should be also considered to minimize ballooning phenomenon since tight contact between a roller and web is required. In this paper, various web materials, PET(Polyester) and OPP(Oriented Poly Propylene) have been selected and investigated to satisfy high-speed printing requirement. Several web speeds, web tensions, and temperature conditions are imposed on each web materials and the pressure and gap profiles as well as nip force have been calculated. Increase of both the winding roller radius and the incoming wrap angle is considered under proper taper tension at 500 m/min of rewinding roller. By solving coupled Reynolds equation and web deflection equation simultaneously, the fluid-structure interaction process has been developed and is applied to the rewinding roller to investigate the ballooning phenomenon which causes guiding problems in high-speed printing performance conditions. By adjusting the linear taper tension, stress distribution between rewinding webs can be remarkably reduced and stable pressure and gap profile with ignorable ballooning phenomenon have been found.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.241-247
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• 2013

The doctor blade is equipped in a toner cartridge and is a device to maintain the uniform thickness of a toner by controlling the pressure on the developing roller. The contact pressure between the developing roller and the doctor blade is one of the significant factors for image quality and durability of toner cartridge. The purpose of this study is to develop approximation model in order to minimize the time and cost which are needed much required in making optimal design of the doctor blade. Central composite design was used for the design of experiment and response surface design was used for approximation. The data for contact pressure were acquired through finite element analysis and data of image density and toner weight were acquired through experiment. The approximation model developed in this study has presented very high fitness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.487-493
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• 2020

Recently, the ministry of environment banned the use of the existing airless method using the spray in painting industrial facilities. Therefore, it is necessary to develop a pressure-roller attached to existing airless painting systems. The hole design of the SUS piping and drum-bases of pressure-rollers currently developed and sold have not been studied in detail, so their efficiency is questionable. In particular, if sufficient paint is not supplied to both ends of the roller, it is necessary to rework with a brush after painting. Therefore, the holes of the drum base need to be distributed so that the paint can flow to both ends of the roller. In this study, numerical analysis was performed to determine the effects of the hole design in the SUS piping and drum-base on the flow patterns of the paint and to suggest more efficient design measures. The analysis results showed that the uniform placement of the holes in the SUS piping is good for the balanced inflow of the paint. For the drum-base, the paint can flow better into both ends of the roller when the holes are concentrated and machined on both ends of the drum-base.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.961-968
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• 2022

Hydrogen embrittlement leads to the damages in bolts, nut, especially, high pressure valves, in the semiconductor facilities, hydrogen vehicles, hydrogen stations and so on. Monel material has higher strength than SUS material. Therefore, even though Monel material with special alloy is usually used to prevent the hydrogen embrittlement, it needs powerful drawing system to manufacture the rectangular or hexagonal bar using circular bar. The purpose of this study is to investigate the characteristics of plastic deformation of Monel material and 2 rollers of rolling unit in plastic limit through numerical analysis. As the results, it was predicted that, based on mean stress, as the rolling step was increased, the rolling force of rolling unit was decreased. In addition, the heat treatment for Monel material was needed because of residual stress due to plastic deformation. As for rollers, the roller was safe about 1.86 times compared with that of ultimate strength. In this study, as the roller 2 showed larger stress than roller 1, thus, roller 2 should be designed carefully to guarantee the safety. Further it was confirmed that the reaction force of roller could be helpful in bearing design.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.123-124
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• 2002

A press shoe is an element of a machine for squeezing water from wood pulp in the field of manufacturing paper. This is used to compress the pulp enveloped by felt sheet with a large roller. The squeezing force is made by hydraulic pressure. The press shoe has a mechanism similar to a partial hydrostatic bearing. The pressure profile between press shoe and roller affects their squeezing ability, and partial peak pressure can tear the wet pulp. The curvature of the surface of press shoe varies to reduce the peak pressure and increase the mean pressure simultaneously. Therefore, the prediction of pressure distribution considering partially changed curvature of hydrostatic bearing is very important for designing the press shoe. In this study, the difference formulation of Reynolds' equation for partial hydrostatic bearing is by direct numerical method and a computer program to calculate the pressure distribution is developed. We investigate the effect of partially changed curvature of bearing surface on the pressure distribution. Other design parameter for hydrostatic bearing such as depth of pocket and relative velocity are also studied.

• KSTLE International Journal
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• v.3 no.2
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• pp.90-94
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• 2002

A press shoe is an element of a machine for squeezing water from wood pulp in the field of manufacturing paper. This is used to compress the pulp enveloped by felt sheet with a large roller. The squeezing farce is made by hydraulic pressure. The press shoe has a mechanism similar to a partial hydrostatic bearing. The pressure profile between press shoe and roller affects their squeezing ability, and partial peak pressure can tear the wet pulp. The curvature of the surface of press shoe varies to reduce the peak pressure and increase the mean pressure simultaneously, Therefore, the prediction of pressure distribution considering partially changed curvature of hydrostatic bearing is very important far designing the press shoe. In this study, the difference formulation of Reynolds equation far partial hydrostatic bearing is derived by direct numerical method and a computer program to calculate the pressure distribution is developed. We investigate the effect of partially changed curvature of bearing surface on the pressure distribution. Other design parameter far hydrostatic bearing such as depth of pocket and relative velocity are also studied.