• Title/Summary/Keyword: lubrication performance

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Evaluation of Lubrication Performance by Laser Texturing Surface Treatment Patterns through Ring Compression Tests (링 압축 시험을 이용한 레이저 텍스처링 표면처리 패턴별 윤활성능 평가)

  • J. S. Choi;W. J. Song
    • Transactions of Materials Processing
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    • v.33 no.4
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    • pp.291-300
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    • 2024
  • To compare the lubrication performance improvement of different laser texturing surface treatment patterns, ring-shaped specimens were prepared by processing line and dot patterns using a fiber laser device. Ring compression tests were conducted to compare the reduction rates of the inner diameter corresponding to the same height reduction of the specimens. Laser processing conditions were set to create patterns with a depth of 9㎛ and a width of 45㎛. Ring specimens were processed with varying spacings between dots and lines. The forging lubricant TECTYL FORM CF 351S was uniformly applied to the upper and lower compression tools, and the rings were compressed by 40% using a hydraulic press, after which the inner diameter was measured. The comparison of inner diameter reduction rates indicated that pattern processing improves lubrication performance, with line patterns being more effective than dot patterns in enhancing lubrication performance.

Lubrication Performance Analysis of A Low-Speed Dry Gas Seal having An Inner Circular Groove (내부 원형 그루브를 갖는 저속 드라이 가스 시일의 윤활 성능해석)

  • Lee An Sung;Kim Jun Ho
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2004.11a
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    • pp.201-208
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    • 2004
  • In this study a general Galerkin FE lubrication analysis method was utilized to analyze the complex lubrication performance of a spiral groove seal having an additional inner circular groove, which was designed for a chemical process mixer operating at a low speed of the maximum 500 rpm. Equilibrium seal clearance analyses under varying outer pressure revealed that the seal maintains a certain levitation seal clearance under the outer pressure of more than about 1.5 bar, regardless of a rotating speed. Also, under the normal outer pressure of 11 bar, the axial stiffness of the seal was predicted to have a high value of more than 7.0e+07 N/m, regardless of a rotating speed and thereby, the seal is expected to maintain a stable thickness of lubrication film under a certain external excitation acting.

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Simulation of the Initial Wear and Lubrication Performance of Marine Engine Components (선박엔진 부품의 성능 향상을 위한 초기 마모 및 윤활 해석 연구)

  • Cha, Su-Bin;Lee, Hyang;Chung, Koo-Hyun
    • Tribology and Lubricants
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    • v.38 no.6
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    • pp.227-234
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    • 2022
  • Recently, the demand for improving energy efficiency has rapidly increased because of the growing concerns over environmental issues. In this work, the tribo-test and simulation for the initial wear and lubrication performance were performed for the piston pin in the small end system of the connecting rod of a marine engine, to obtain useful data for improving the efficiency of marine engine systems. In addition, a diamond-like carbon (DLC) coating was applied to the piston pin to explore feasibility of eliminating the bush used in the system. The initial wear and lubrication characteristics between the uncoated piston pin and bush were compared with that between the DLC-coated piston pin and connecting rod in the tribo-test. The simulation for the wear and lubrication performance according to the wear progression was conducted based on the data obtained from the test. The wear characteristics were quantitatively assessed by the wear depth and wear volume, and the lubrication performance was characterized with the change of pressure and minimum oil film thickness with respect to the crank angle. It was found that the DLC-coated piston pin may provide better initial wear characteristics and lubrication performance. The results of this work may provide fundamental information for marine engines with improved efficiency.

Grease Life and Degradation Characteristics in Rolling Bearing Lubrication (특성별 그리이스의 수명과 열화특성 연구)

  • 김상근;박창남;한종대
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.11a
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    • pp.179-185
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    • 2001
  • High performance characteristics are required for rolling bearings and the various functions of bearing are greatly influenced by grease. Recently, higher performance is being demanded of rolling bearing greases for bearing lubrication. Four special greases with different composition such as lithium soap/ester oil, urea/ester oil, urea/ether oil and PTFE/fluorine oil were synthesized to compare the performance of these greases with that of the conventional lithium soap/mineral oil grease. The grease properties were investigated using a series of typical grease testing methods and grease life test. After the life test, the greases were charaterized by FTIR analysis and a microscope. And the iron amount in the greases was analyzed by AAS after ashing. The composition and manufacturing process determined the grease performance. The grease with a base oil of synthetic oil showed higher performance and the urea/ester oil and PTFE/fluorine oil showed about three times longer life as compared with conventional lithium grease.

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Study on Boundary Lubrication in the Sliding Bearing System under High Load and Speed (고하중과 고속 미끄럼 베어링 시스템의 경계윤활에 대한 연구)

  • 장시열
    • Tribology and Lubricants
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    • v.15 no.3
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    • pp.248-256
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    • 1999
  • Many tribological components in automobile engine undergo high load and sliding speed with thin film thickness. The lubrication characteristics of the components are regarded as ether hydrodynamic lubrication or boundary lubrication, whereas in a working cycle they actually have both characteristics. Many modem engine lubricants have various additives for better performance which make boundary film formation even under hydrodynamic lubrication regime. Conventional Reynolds equation with the viewpoints of continuum mechanics concerns only bulk viscosity of lubricant, which means that its simulation does not give insights on boundary lubrication characteristics. However, many additives of modern engine lubricant provide mixed modes of boundary lubrication characteristics and hydrodynamic lubrication. Especially, high molecular weight polymeric viscosity index improvers form boundary film on the solid surface and cause non-Newtonian fluid effect of shear thinning. This study has performed the investigation about journal bearing system with the mixed concepts of boundary lubrication and hydrodynamic lubrication which happen concurrently in many engine components under the condition of viscosity index improver added.

Lubrication Performance Analyses of Spiral Groove Dry Gas Seals - Part I: EE Analysis and Basic Performance Evaluation (스파이럴 그루브 드라이 가스 시일의 윤활 성능해석 - Part I: 유한요소 해석 및 기본 성능평가)

  • Lee An Sung;Yang Jae-Hun;Choi Dong-Hoon
    • Tribology and Lubricants
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    • v.20 no.2
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    • pp.58-67
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    • 2004
  • In this study a general Galerkin FE lubrication analysis method for the compressible Reynolds equation in cylindrical coordinates is presented. Then, the method is applied for analyzing lubrication performances of spiral groove dry gas seals. The effects of toning and number of groove on performance indices are evaluated at low and high rotating speeds: 3,600 and 15,000 rpm. Results show that, for the primary design consideration performances such as the opening force and axial and angular stiffnesses, a negative or small coning and a large number of groove are preferred.

Lubrication Performance Analysis and Experiment of a Low-Speed Dry Gas Seal having an Inner Circular Groove (내부 원형 그루브를 갖는 저속 드라이 가스 시일의 윤활 성능해석 및 실험)

  • Lee, An-Sung;Kim, Jun-Ho
    • Tribology and Lubricants
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    • v.21 no.2
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    • pp.53-62
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    • 2005
  • In this study a general Galerkin FE lubrication analysis method was utilized to analyze the complex lubrication performance of a spiral groove seal having an additional inner circular groove, which was designed for a chemical process mixer operating at a low speed of the maximum 500 rpm. Equilibrium seal clearance analyses under varying outer pressure revealed that the seal maintains a certain levitation seal clearance under the outer pressure of more than about 1.5 bar, regardless of a rotating speed. Also, under the normal outer pressure of 11 bar, the axial stiffness of the seal was predicted to have a high value of more than 7.0 e + 07 N/m, regardless of a rotating speed and thereby, the seal is expected to maintain a stable thickness of lubrication film under a certain external excitation acting. A seal levitation test rig was designed and constructed. Experimental results at 500 rpm agreed well with analytical predictions and the applied lubrication analysis method was verified.

INVESTIGATIONS ON DRILLING SCM 440 STEEL WITH ELECTRO STATIC LUBRICANTION (ESL) SYSTEM

  • Reddy, N. Suresh Kumar;Jeon, Kang-Min;Yang, Min-Yang
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1010-1015
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    • 2008
  • The rapid wear rate of cutting tools due to high cutting temperature is a critical problem to be solved in machining of hardened steel. Application of cutting fluid influences the performance of machining because of its lubrication and cooling actions. But, the environmental concerns call for the reduced use of cutting fluids in machining operations. Near-dry machining such as minimum quantity lubrication is regarded as one of the solutions to this difficulty. In the present work, cutting fluid was applied as a high velocity jet at the machining zone continuously at an extreme low rate using a fluid application system developed namely Electro Static Lubrication (ESL) during drilling of hardened steel. The performance of ESL has been compared with that of dry and MQL (minimum quantity lubrication) machining.

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Lubrication Performance Analysis of Deep Straight Groove Seal (깊은 직선 홈 시일의 윤활 성능해석)

  • Lee An Sung;Kim Jun Ho
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2003.11a
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    • pp.193-200
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    • 2003
  • In this study a general Galerkin FE formulation of the incompressible Reynolds equation is derived for lubrication analyses of noncontacting mechanical face seals. Then, the formulation is applied to analyze the flexibly mounted stator-type reactor coolant pump seals of local nuclear power plants, which have deep straight grooves or plane coning on their primary seal ring faces. Their various lubrication performances have been predicted. Results show that the analyzed deep straight groove seal should have a net coning of less than $0.6\;{\mu}m$ to satisfy the leakage limit. And for the same amount of equilibrium opening force the plane coning seal requires to have a 3 times higher dimensionless coning than the deep straight groove seal.

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A Study on Synthesis and Characteristics of The Optimum Rolling Bearing Greases (최적 베어링 윤활 그리이스의 합성과 특성연구)

  • Kim Sang-Keun;Park Chang-Nam;Han Jong-Dae;Son Gwan-Su
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2003.11a
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    • pp.129-138
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    • 2003
  • Rolling bearings are classified one of the most important machine elements. The various function of bearings are greatly influenced by grease, and higher performance of rolling bearing greases is required in improve bearing lubrication. Three urea/ether oil greases with identical composition were synthesized to compare the performance of these greases according to the thickener content of grease. The typical grease physical properties were investigated. And life test of these greases was conducted by FE-9 grease life tester. The characteristics of the greases before and after life test were investigated using FT-IR, microscope, OIT and TAN meter. Large differences in the grease performance depending on the content of the thickener were observed. The grease with higher content of the hickener showed higher performance such as long life time and low TAN value. After preliminary test, twelve greases were synthesized and evaluated the performance of dropping point and OIT, then optimized two greases were selected by SSRED (Six Sigma Robust Engineering Design) using dropping point and OIT data. Characteristics of the optimized two greases were on the same level with estimated value. The optimized grease by means of OIT value showed longer grease life in comparison with optimized grease by dropping point. However two greases showed higher performance than typical urea/ether oil.

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