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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society of Tribologists and Lubrication Engineers
Journal Basic Information
Journal DOI :
The Korean Society of Tribologists and Lubrication Engineers
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Volume & Issues
Volume 24, Issue 6 - Dec 2008
Volume 24, Issue 5 - Oct 2008
Volume 24, Issue 4 - Aug 2008
Volume 24, Issue 3 - Jun 2008
Volume 24, Issue 2 - Apr 2008
Volume 24, Issue 1 - Feb 2008
Selecting the target year
Development of Internal Friction Model in Automotive Constant Velocity Joints
Lee, Chul-Hee ; Jang, Min-Gyu ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 5, 2008, Pages 215~220
An internal friction model was developed to model the frictional behavior of automotive Constant Velocity (CV) joints by using the test data from an instrumented CV joint friction apparatus with actual driveshaft assemblies. Experiments were conduced under different realistic operating conditions of oscillatory speeds, CV joint articulation angles, lubrication, and torque. The experimental data were used to develop a physics-based semi-empirical CV joint internal friction coefficient model as a function of different CV Joint operating parameters. It was found that the proposed friction model captures the experimental results well not only the static behavior of friction coefficient, but also the dynamic friction terms, which is the main source of force that causes vehicle vibration problems.
Design of Noncircular Gears for Wire EDM
Lee, Sung-Chul ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 5, 2008, Pages 221~227
This paper presents a step-by-step design of noncircular gears. From the diagram of angular velocity ratio of a noncircular gear pair, the pitch curves of the two mating gears are determined, and the perimeter of the pitch curve has been divided into equal-length segments by the number of teeth. A master tooth profile, which is a composite curve of circular arcs that represents involute, has been introduced. A noncircular gear pair has been designed by imposing the master tooth on the divided points of the pitch curve, and a full fillet has been achieved between neighbour teeth. Thus, the whole profile of the noncircular gear is a composite curve of arcs only, and consequently NC codes for wire EDM can be easily generated.
Design of Shoulder Height for Ball Bearing using Contact Analysis
Kim, Tae-Wan ; Yoon, Ki-Chan ; Cho, Yong-Joo ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 5, 2008, Pages 228~233
In this study, the methodology for determination of shoulder height in the internal shape design of ball bearing using 3D contact analysis is proposed. The static analysis of a ball bearing was performed to calculate the distribution of applied contact load and angles among the rolling elements. From each rolling element loads and the contact geometry between ball and inner/outer raceway, 3D contact analyses using influence function are conducted. These methodology is applied to HDD ball bearing. A critical axial load and a critical shoulder height which are not affected by edge are calculated. The proposed methodology may be applied to other rolling element bearing for the purpose of reducing the material cost and improving the efficiency of the bearing design process.
Effects of Surface Texturing under Grease Lubrication
Kim, Sung-Gi ; Song, Kuen-Chul ; Kim, Sang-Beom ; Chae, Young-Hun ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 5, 2008, Pages 234~240
It is well known that surface texturing improves the tribological properties of mechanical components for enhancing hydro-dynamic effect or serving as a micro reservoir. There are not, however, enough researches to reveal the effects of surface texturing on the tribological properties under grease lubrication which is used in lubricating many mechanical elements. In the present study, therefore, the effects of surface texturing on the tribological properties are investigated under grease lubrication based on an experimental approach. The results show that surface texturing decreases friction coefficient. It is found that the friction coefficient can be decreased by controlling the diameter and density of micro-dimple. The diameter of dimple is more effective under high load and low speed than otherwise. And, the density of dimple is effective under low load and high speed.
Effects of Tribological Parameters on the Nonlinear Behavior of a Spur Gear Pair with One-Way Clutch
Cheon, Gill-Jeong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 5, 2008, Pages 241~249
This paper describes the tribological effects on the nonlinear behavior of a spur gear pair with one-way clutch according to the direct contact elastic deformation model over a wide range of speeds, considering the hydrodynamic effects. The effects of various lubrication parameters, such as viscosity, film width, and friction, on the nonlinear dynamic behavior were analyzed. Forces due to the entraining velocity and the hydrodynamic friction were about two orders smaller than normal forces over the whole speed range. While the viscosity has a strong effect on the behavior of gear pair systems, friction has very little effect on torsional behavior. The inclusion of the hydrodynamic effect facilitates nonlinearity by increasing the overlap and damping, as well as decreasing elastic deformation and tooth reaction forces.
A Study on Fretting Wear of CrN and TiN coated Tubes in a Nuclear Steam Generator
Lee, Young-Ze ; Park, Jung-Min ; Jeong, Sung-Hoon ; Kim, Jin-Seon ; Park, Se-Min ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 5, 2008, Pages 250~254
The steam generator of nuclear power plant is composed with the bundles of long tubes. It is exposed fluid flow and weak in the vibration. The tubes are supported by anti-vibration bars. Due to vibration the wear damage is called as the fretting wear. It should be minimized for the safety of the plants. The hard coatings are very effective to reduce the amount of wear. The coatings of TiN and CrN are introduced in this study to protect the fretting surfaces. The tube-on-flat type tester was used for fretting wear tests. The results show that the wear amounts of the coated tubes were decreased depending on coating thickness. CrN was very effective to reduce the wear. In case of TiN the wear amounts were dependent on the coating thickness. Thick coating of TiN was very effective for wear resistance.
Adhesion Characteristics between Mold and Thermoplastic Polymer Film in Thermal Nanoimprint Lithography
Kim, Kwang-Seop ; Kang, Ji-Hoon ; Kim, Kyung-Woong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 5, 2008, Pages 255~263
Adhesion tests were conducted to investigate the adhesion characteristics between mold and thermoplastic polymer film. Coating of anti-sticking layer (ASL), a kind of polymer material, imprint pressure, and separation velocity were considered as the process conditions. A piece of fused silica without patterns on its surface was used as a mold and the thermoplastic polymer films were made on Si substrate by spin-coating the commercial polymer solution such as mr-I PMMA and mr-I 7020. The ASL was derived from (1H, 1H, 2H, 2H - perfluorooctyl) trichlorosilane(
-OTS) and coated on the fused silica mold in vapor phase. The pull-off force was measured in various process conditions and the surfaces of the mold and the polymer film were observed after separation. It was found that the adhesion characteristics between the mold and the thermoplastic polymer film and the release performance of ASL were changed according to the process conditions. The ASL was effective to reduce the pull-off force and the damage of polymer film. In cases of the mold coated with ASL, the pull-off force did not depend on imprint pressure and separation velocity.
A Study on Friction and Wear Characteristics of Nano-size Carbon
Jung, Kwang-Woo ; Choi, Jeong-Kyu ; Moon, Seong-Yong ; Chung, Keun-Woo ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 5, 2008, Pages 264~268
A large number of additives have been used with the efforts of improving the performance of lubricants used along with the development of internal combustion engine. In this study, nano-sized graphite was used as liquid-lubricant additive. In order to disperse graphite into oil, we esterified the nano-carbon manufactured by our company with various types of alcohol. After measuring the anti-wear in accordance with the types of alcohol and added concentration, it has been found that its anti-wear/friction decrease has been improved in case of adding 0.1% of the sample composed with C12/14 mixed alcohol & hexadecanol.
Tribological Characteristics of Carbon Nanotube Aluminum Composites According to Fabrication Method and Content of Carbon Nanotube
Lee, Young-Ze ; Lee, Jung-Hee ; Kim, Il-Young ; Lee, Gyu-Sun ; Baik, Seung-Hyun ; Youn, Jeong-Il ; Kim, Young-Jig ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 5, 2008, Pages 269~274
Carbon nanotube composite is considered to be a good candidate material for composite material because of its excellent mechanical property and low density under high temperature as well as good wear and frictional properties. In this study, tribological characteristics of carbon nanotube aluminum composite were evaluated using pin-on-disk wear tester. Spark Plasma Sintering method is more effective than Hot Pressing method in terms of wear and friction. The composite with 1% CNT has the lowest friction and wear characteristic.