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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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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 14, Issue 4 - Dec 1998
Volume 14, Issue 3 - Sep 1998
Volume 14, Issue 2 - Jun 1998
Volume 14, Issue 1 - Mar 1998
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An Experimental Study of Environmental Effects on the Rolling Resistance of Bearings Coated by Soft Metallic Films
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 1~6
An experimental study was performed to discover the effect of environmental conditions on the rolling resistance behavior of pure silver and lead coated 52100 bearing steel. Pure silver and lead coatings were produced by a thermal evaporation coating method. Experiments using a thrust ball bearing-typed rolling test-rig were performed under vacuum, dry air and controlled humidity conditions. Results showed that agglomeration of particles were suppressed in vacuum environment and resulted in low and stable rolling resistance by shakedown phenomena. Also, humidity related closely to the agglomeration of particles and the rolling resistance after the failure of coated layer.
The Effect of the Activation of Phosphoric Ester Cellulose Particles on the Electrotheological Properties of Anhydrous ER Fluids
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 7~16
The electrorheological (ER) behavior of suspensions in silicone oil of phosphoric ester cellulose powder (average particle size: 17.77
m) was investigated at room temperature with electric fields up to 2.5 KV/mm. For development of anhydrous ER suspensions using at wide temperature range, we aimed to know the effect of activation of phosphoric ester cellulose particles on the ER activities. As a first step, the anhydrous ER suspensions mixing with the phosphoric ester cellulose particles which were treated with 2M phosporic acid and 4M urea were measured. After activating the anhydrous ER suspensions at 12
, not only the analysis of dispersing cellulose particles which were reacted by phosphoric ester but also the electrorheological characteristics of ER suspensions such as dielectric constant, current density, electrical conductivity and rheological properties were studied. From the experimental results, the activation of phosphoric ester cellulose particles had an influence on the ER properties of anhydrous ER suspensions. As the activation time went by, the size and number of dispersing particles, the electrical properties and the initial apparent viscosity
of ER suspensions were increased till the activation time passed 5 hours. Also, it was possible, the electrorheological effect $(
_0)$ of ER fluids was grown by the activation of phosphoric ester cellulose particles.
Effect of Different Solid Lubricants in the Automotive Friction Material on Friction Characteristics
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 17~23
Friction materials with three different formulations containing different solid lubricants were investigated to study the role of lubricants on the friction performance. The three friction materials contained graphite 10 vol.%, graphite 7 vol.%+
3 vol.%, and graphite 7 vol.%+
3 vol.%, respectively, with the same amount of other ingredients. Results of this work showed that each formulation with different lubricants had unique advantages and disadvantages. The friction materials containing graphite 7 vol.%+
3 vol.% and graphite 7 vol.%+
3 vol.% showed better resistance to fading and improved friction stability compared to the friction materials containing graphite only as a lubricant. However, the friction materials with two lubricants (graphite+
) showed disadvantages on DTV generation and rotor wear.
A Digital Control of Squeeze Film Damper
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 24~31
A new type squeeze film damper is proposed and its dynamic characteristics are investigated experimentally. The new one has a pulsating flow supply system which properly adds high pressure oil to the oil film of the damper so that the rotor vibration can be controlled actively. As the result, the amplitude of the rotor vibration can be reduced considerably. The algorithm which compensates the phase lag of servo valve as well as the high-performance servo valve are required in order that a new type squeeze film damper can be more effective device to attenuate the rotor vibration than typical one.
Numerical Study on the Magnetic Flux Distribution of a Magnetic Fluid Seal
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 32~38
This paper presents the magnetic flux distributions of a ferrofluid seal at the sealing gap between the pole pieces and the rotating shaft. The optimized shape of pole pieces has been determined by using the computer simulations. The computed results indicate that the sloped pole piece of 27
shows good flux distributions compared with that of the conventional flat pole pieces and may reduce frictional heats due to a reduced surface contact areas of magnetic fluids.
Analysis of Connecting Rod Bearings Using Mass-Conserving Boundary Condition
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 39~45
Reynolds equation, which describes behavior of fluid film in journal bearings, basically satisfies mass conservation. But, boundary conditions usually used with this equation, e.g. half Sommerfeld or Reynolds boundary conditions, cannot fulfill this natural law of conservation. In the case of connecting rod bearing, where applied load is dynamic and its magnitude is relatively large, such unrealistic boundary conditions have serious influence on calculation results, especially on lubricant flow rate or power disspation which are important parameters in thermal analysis. In this paper, mass-conserving boundary condition was applied in the finite element analysis of connecting rod bearings. Lubricant flow rate and power dissipation rate were calculated together with journal center locus, minimum film thickness and maxmium film pressure. These computation results were compared with those of the case of Reynolds boundary condition. Balance between inlet and outlet flow rate was well achieved in the case of mass-conserving boundary condition.
Effect of Crystalline Lameliar Orientation on the Creep and Wear of Ultra-high Molecular Weight Polyethylene
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 46~50
Analysis for Lubrication of the Piston Ring Considering Oil Transport
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 51~58
This paper considers analysis of the lubrication between the piston ring and the cylinder liner. Piston ring lubrication analysis considering oil transport is important because oil consumption is an essential factor to design the piston assembly. To develop the lubrication analysis program for the piston ring, oil continuity condition and open-end boundary assumption are used for computational boundaries. Results show that oil continuity can be almost satisfied at any crank angle in and out of the piston ring clearance. Therefore the amount of oil consumption and the dynamic behavior of ring pack can be estimated using this algorithm. And it can be known that the effective width may be smaller than the full width of the piston ring, so oil starvation condition should be considered for the lubrication analysis of the piston ring.
A Study on the Cam Ring Deformation in a Balanced Type Vane Pump
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 59~64
This paper presents the deformation characteristics of cam ring in a balanced type vane pump. Cam ring is operated in the high-pressure condition. Therefore the local deformation of cam ring affects the characteristics of compression, vane motion and noise and vibration. We analyzed the deformation of cam ring for the three types by using the finite element method. The deformed shape of cam ring and the effects of deformation on the compression are presented. As a result of analysis, we know that the right hole of the cam ring has advantage for reducing the pressure overshoot.
A Study on Dynamic Analysis and Friction Loss of Swash Plate Compressor
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 65~73
A dynamic analysis and friction loss of non-variable swash plate compressor are studied theoretically. Rotating swash plate and reciprocating pistons are modelled kinematically, and forces and torques acting on rotor-bearing system are analyzed. Then, friction losses on 4 roller bearings, 10 sliding parts between swash plate and shoes, and 10 lubricating surfaces between cylinders and pistons are calculated. On each frictional element of sliding surfaces and roller bearings, the same friction loss is obtained, respectively.
Applicaion of Neural Network for Machine Condition Monitoring and Fault Diagnosis
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 74~80
The morphologies of the wear particles are directly indicative of wear process occuring in the machine. The analysis of wear particle morphology can therefore provide very early detection of a fault and can also ofen facilitate a dignosis. For this work, the neural network was applied to identify friction coefficient through four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) of wear debris generated from the machine. The averages of these parameters were used as inputs to the network. It is shown that collect identification of friction coefficient depends on the ranges of these shape parameters learned. The various kinds of the wear debris had a different pattern characteristics and recognized relation between the friction condition and materials very well by neural network. We discuss how the network determines difference in wear debris feature, and this approach can be applied for machine condition monitoring and fault diagnosis.
Development of Measurement System for Tappet Rotation in the Valve Train System
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 81~86
The purpose of this paper is to measure the rotational speed of tappet in OHC valve train system. Tappet has eccentricity about cam center, which induces the tappet rotation and prevents from wear. In this paper, the experimental test rig which composes of one cam system is developed to measure the tappet rotation by using the laser generating system, rotary encoder, optical fiber, and photo transistor. The direction of tappet rotation is judged from the oder of optical signal. As results of experiment, average and instant rotational speed and average rotation angle per one cam revolution are presented. Measured results show that eccentricity ratio is dominant factor for the tappet rotation, and tappet is rotated at the base circle.
Analysis of Crank Pin Bearing with Various Inlet Groove Shape for Marine Engine
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 87~93
Crank pin bearing in two-stroke marine diesel engine is operated under quite severe conditions since the elements are big and heavy and the sliding speed is very slow. Therefore it is very difficult to form oil film. In this paper, two types of bearings with different groove shape are compared. One has circumferential oil groove at lower position and the other has lengthwise oil groove at upper position. Bearing clearance, oil inlet pressure and length to diameter ratio are selected as design parameters. Locus of journal center and minimum oil film thickness are investigated to compare two cases.
The Static Equivalent Radial Load under the Moment and Radial Force for the Deep Groove Ball Bearings
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 3, 1998, Pages 94~99
Generally not only the radial load but also the moment may be applied to the ball bearings for a shaft system. However it has been difficult to determine the static equivalent load because there is the radial static equivalent equation only for the axial and radial force on the bearings. In this paper, the same static equivalent radial load which makes the maximum contact force at the interface between the ball and groove as the applied radial force and moment generate is calculated under the condition that the radial force and the moment are applied to the bearings simultaneously. The relation between the static equivalent load and applied force is studied. Therefore the simple and effective equation for the static equivalent radial load of the radial load and moment is proposed for the deep groove ball bearings.