• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1437-1442
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• 2010

A slipper metal is used for power transmission in the aluminum hot rolling process. The slipper metal connects a spindle with a coupling. Therefore, if the slipper metal is seriously damaged, the spindle and the coupling will crash into each other. Therefore, preventing the destruction of the slipper metal is essential for ensuring a long mechanical life cycle. In this study, the structural analysis and optimal design of the slipper metal was carried out by finite element method for life extension of the slipper metal. To verify the interference of spindle assembly with modified slipper metal, a kinematics simulation was performed by applying various combinations of dynamic boundary conditions. As a result of structural analysis and optimal design of the slipper metal, the maximum stress of the modified slipper metal was lower than that of the initial model by 22%.

• Tribology and Lubricants
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• v.29 no.3
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• pp.186-191
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• 2013

Hydraulic systems are used to transform mechanical energy into fluid energy and vice versa. They are widely applied in various industries; e.g., they are used in automobiles, public works, rockets, machine tools, heavy construction equipment, and airplanes. Hydraulic pumps are used to transform the energy in these systems. In this study, with the basic operation principles as a starting point, I attempted to clarify how the shape of a slipper affects the lubrication characteristics under practical conditions. A swashplate with a tilt angle of zero and capable of rotating motion was used, along with other devices. A slipper was located at 45 mm eccentricity from the center of the swashplate. The results of this experiment indicated that the shape of the bottom surface of a slipper affects the load capacity, leakage flow, and lubrication characteristics and that the slipper is one of the most important parts for improving the pump efficiency.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.62-67
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• 2000

This paper was undertaken to do morphological analysis of wear debris for slipper-Pad of hydraulic rotary acuator. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters(50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear debris. The results showed that the four shape parameters of wear debris depend on a kind of the lubricating condition. It was capable of presuming wear volume for slipper-pad of hydraulic rotary acuator on driving time.

• Journal of Drive and Control
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• v.10 no.1
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• pp.14-20
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• 2013

In the high rotational speed and pressure state, the leakage flow rate of the axial piston pump is one of the serious problems and make great reasons to decrease the volume efficiency. In this study, tribology characteristics is clarified for the hydrostatic slipper bearing in the swash plate type axial piston pump, by means of theoretical analysis for the different shape of the hydrostatic slipper bearing. It was analyzed by Mathcad software and used equal conditions at $0^{\circ}$ swash plate angle in each model. The results show that performance characteristics of the swash plate type axial piston pump are significantly influenced by the shape of the hydrostatic slipper bearing.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.645-649
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• 1997

In case of swash plate type axial piston hydraulic motor, hydrostatic bearing used to achieve the lubrication effect on the mechanical sliding contact areas between the following parirs ; sliooer-pad and swash plate,piston and cylinder bore,valve plate and cylinder block, etc. This study discussed the basic charateristic for the hydrostatic slipper-pad bearings with the capillary or orifice restrictor under static load condition. And, we also development of hydrostatic bearing tester for hydrostatic balancing test of pistion & slipper-pad assembly, and some experimental data on supply pressure step responce are reported.

• Tribology and Lubricants
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• v.24 no.6
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• pp.343-348
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• 2008

In this paper, a CFD (Computational fluid dynamics) code, FLUENT is adopted to investigate accurate flow characteristics for a slipper bearing which is used swash plate type hydraulic axial piston pump. Static pressure and velocity distributions, and velocity vectors are plotted for different film thickness and slipper rotational velocity. In recess region, there exists a doughnut shaped vortex ring. The static pressure distributions are non-uniform and the flow fields are highly asymmetrical under bearing rotation. Therefore the numerical method adopted in this paper can be use in design of hydrostatic components and further studies are required.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.674-680
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• 2005

The top spindle, end coupling and slipper metal are important components of the hot rolling process and are used for transmission of heavy rotational power. In this study, kinematic analysis is conducted using finite element method for hot rolling process under slipper metal combination types and operation situations. The structural analysis is performed by applying the combination type, rotational boundary condition of top spindle, end coupling and slipper metal. This study aims to minimize the mechanical problems which might happen in the production process.

• Journal of the Korean Society of Physical Medicine
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• v.2 no.2
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• pp.161-171
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• 2007

Purpose : The purpose of this study was to evaluate the effect of footwear on gait in older adults. Methods : The footwear consists of loafer with fixation and mule and slipper without fixation. Twenty one female older adults voluntarily participated in this study. Each participant walked on the gait system GAITRite and measured temporal-spatial gait parameters. And the participants wore loafer, mule, slipper randomly. We measured stance time, swing time, heel-to-heel BOS, double support time, velocity, cadence, FAP as temporal-spatial gait parameters. Results : Three gait parameters showed significant difference statistically among 7 gait parameters. The stance time increased as loafer, mule, barefoot, slipper orderly. And there was a significant difference statistically (p<.05). The swing time increased as slipper, barefoot, mule, loafer orderly. And there was a significant difference statistically(p<.05). And the heel-to-heel BOS increased as barefoot, loafer, mule, slipper orderly. And there was a significant difference statistically(p<.05) according to footwear type. Conclusion : The footwear type with high stability like loafer is considered better than footwear type with low stability like mule and slipper for the elderly.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.3
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• pp.1-6
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• 2007

The leakage generated from the clearance between the cylinder bore and the piston is one of the most serious problems in the hydraulic piston pump, and it even results in terrible decrease of the volume efficiency at a great velocity and high pressure. In this paper, the lubrication characteristic of the hydrostatic slipper bearing equipped in the hydraulic piston pump has been worked out by experimentation with three model bearings of different shape. Preparatory to this, not only the three models of piston-slipper were designed, but the corresponding experimental apparatus were also manufactured. As a result, it was verified that, according to the supply pressure, the hydrostatic bearing part of the slipper is severely affected by the pocket pressure, land pressure, oil film thickness, and leakage flow.

• Mycobiology
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• v.50 no.2
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• pp.142-149
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• 2022

Orchids live with mycorrhizal fungi in mutualism. This symbiotic relationship plays an essential role in the overall life cycle of orchids from germination, growth, settlement, and reproduction. Among the 1000 species of the orchid, the Korean lady's slipper, Cypripedium japonicum, is known as an endangered species. Currently, only five natural habitats of the Korean lady's slipper remain in South Korea, and the population of Korean lady's slipper in their natural habitat is not increasing. To prevent extinction, this study was designed to understand the fungal community interacting in the rhizosphere of the Korean lady's slipper living in the native and artificial habitats. In-depth analyses were performed to discover the vital mycorrhizal fungi contributing to habitat expansion and cultivation of the endangered orchid species. Our results suggested that Lycoperdon nigrescens contributed most to the increase in natural habitats and Russula violeipes as a characteristic of successful cultivation. And the fungi that helped L. nigrescens and R. violeipes to fit into the rhizosphere community in Korean lady's slipper native place were Paraboeremia selaginellae and Metarhizium anisopliae, respectively. The findings will contribute to restoring and maintaining the endangered orchid population in natural habitats.