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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
Editor in Chief :
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
Selecting the target year
Electrorheological Properties of Anhydrous ER Suspensions Based on Phosphated Cellulose
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 1~9
The electrorheological (ER) behavior of suspensions in silicone oil of phosphated cellulose particles (average particle size 17.77
) was investigated at room temperature with electric fields up to 2.5 KV/mm. In this paper, for development of anhydrous ER suspensions using at wide temperature range, we would like to know fundamental understandings on the ER activity. As a first step, the anhydrous ER suspensions dispersed the phosphated cellulose particles were measured, and not only the electrical characteristics such as dielectric constant, current density and electrical conductivity but also the rheological properties on strength of electric field and quantity of dispersed phase were studied. From the experimental results, the anhydrous ER suspensions dispersed phosphated cellulose particles showed a stable current density and very high performance of ER effect
on the 2.5 KV/mm and the dynamic yield stress
was in exponential proportion to the strength of electric fields.
The Effects of Relative Material Properties on the Friction and Wear Behavior of Pure Metals
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 10~20
In this paper, the effects of material properties on the friction and wear behavior of pure metals are investigated. The sliding material pairs are selected based on their relative compatibility and relative hardness ratio of the specimen. The initial and steady-state friction coefficients are obtained in the experiments and the wear rates are quantitatively investigated. It is shown that the initial friction coefficient is affected by the hardness ratio of sliding materials. Furthermore, in steady state condition, neither hardness ratio nor compatibility has significant influence on the frictional behavior. As for wear, the ductility of the metal affects the wear particle generation process which in turn affects the frictional behavior. The findings of this research suggest that frictional interaction cannot be simply characterized by either compatibility or hardness ratio of the materials undergoing sliding contact.
Experimental Study on Friction Characteristics in Lip-Type Oil Seals
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 21~25
This paper presents the experimental results of the friction characteristics of double liptype oil seals which show an improvement in sealing performance over single lip-type oil seals. The major differences between two oil seals are the number of contact lip, and seal materials; Nitrile Butadine Rubber(NBR) and urethane rubber. The measured results show that the friction torques of double lip seals show 12-17% increases compared with those of single lip-type seals. But the sealing performance and service life of double lip oil seals have been increased and stabilized due to an optimized design of the seal lip and material properties.
Performance Analysis of High-Speed Ceramic Ball Bearings Under Thrust Loads in EHD Lubrication
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 26~34
This paper presents a high-speed performance analysis of ball bearings with ceramic balls under thrust loads. The sliding velocity profiles between a ball and raceways were obtained by the 3-D quasi-dynamic equations of motion including both centrifugal force and gyroscopic moment derived by vector matrix algebra. The friction at the contact areas was obtained by the Bair-Winer's non-Newtonian rheological model and the Hamrock-Dowson's central film thickness in EHL analysis. The nonlinear equations were solved by the Newton-Raphson method and the underrelaxation iterative method. The friction torques and ball behaviors with various loads, ball materials, and contact angles were predicted by this model. It was shown that the friction torque was sensitive to thrust load and contact angle, and that the friction torque and the pitch angle of the bearing with ceramic balls are smaller than those of the bearing with steel balls.
Tribological Behaviour of
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 35~41
solid lubricant synthesized through the vapour phase transport method was coated on the commercial bearing steel (SUJ 2) substrate, and the tribological behaviour of the lubricant was investigated using a ball-on-disk type tester. The
powder was spray-coated at room temperature using compressed air, and the change of friction coefficient was examined in various conditions, i.e., specimen configuration, atmosphere (air and nitrogen), applied load and rotating speed.
coated ball and disk showed the optimum friction coefficient of 0.07 and wear life of 45,000 cycles in the nitrogen atmosphere under 0.3 kgf and 100 rpm, whereas relatively high coefficient of 0.13 and reduced wear life of 4,000 cycles were observed in air atmosphere. The effect of rotating speed on the friction coefficient was not observed both in nitrogen and in air atmospheres. This confirmed that the spray-coated
solid lubricant was effective in reducing the friction coefficient and improving wear life in nitrogen atmosphere, and the oxygen and moisture existing in air could seriously deteriorate the lubrication effect of
Evaluation of Apparent Viscosity Properties for Electro-Rheological Fluid
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 42~48
Electro-Rheological (ER) fluid is a class of functional fluid whose apparent viscosity can be varied by the applied electric field strength. The ER fluid is classified into two types; one is a dispersive fluid and the other is a homogeneous. Dispersive ER fluid is a colloidal suspension of fine semiconducting particles in a dielectric liquid and liquid crystal (LC) is classed as homogeneous type ER fluid. LC has been originally developed for some electronic display devices. Various mechanical components applying ER fluid have been developed, and the their performance typically depends on the characteristics of ER fluid which have generally been evaluated by a rotational viscometer. However, the ER fluid introduced into various mechanical components undergoes not only simple shear flow but press flow or oscillating flow. For the evaluation of ER fluid, the authors developed an reciprocating type viscometer. The amplitude is controlled on 5 mm at the frequency from 50 to 1000 Hz. In the present paper, the performance of several types of ER fluid is evaluated by the reciprocating type viscometer and compared with those evaluated by a rotational viscometer.
Numerical Study of Thermal Deformations Due to Frictional Heatings in a Mechanical Face Seal
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 49~56
The thermal deformation of the contact seal components has been analyzed using the finite element method. The temperature distributions, the thermal deformations and contact stresses are solved numerically for the contact surface with wear coning effects. The thermal deformation is always shown to distort the sealing surface along the radius of the seal ring. The results show that the deformations of inner radius side are significant compared with those of outer radius. Thus, the thermal deformation due to thermal heatings may promote the coned face wear or wear related thermal cracks at the contacting face of the seal ring component.
Effects of Tribological Characteristics on Lubricants Properties (The 1st)
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 57~62
When lubricants is used under severe running conditions, their tribological characteristics are very important. We have studied the lubricating oil viscosity, kinds of additives and their amounts, and lubricating oil temperatures were changed. In order to study the effect of oil temperature on the wear of the surface, the temperature of the oil was changed for the same sample. Moreover, the temperatures of three kinds of oils which have very different viscosities at room temperature, were varied between 6
while the oil viscosity was unchanged. It was shown from the test results that surface wear is not greatly affected by the amount of ZnDTP (Zinc dialkyl dithio phosphate) antiwear agent, but EP (Extreme pressure) additives are less effective against wear than ZnDTP additives. The viscosity of lubricating oil and its temperature greatly affect the wear of the surface. Combining all the wear data with those of the surface strength, it was observed that the higher the load, the wider the scratching of wear, and also in the case of the same running load, the lower the wear, the longer the life of the surface strength.
Wear Reduction of Tappet Surface by Undulated Surface
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 63~74
The damage of cam/tappet surface is one of the major reasons for energy loss in an I.C. engine. High friction causes the accelerated wear of the cam/tappet surfaces which in turn changes the valve opening/closing timing. During the accelerated test evidence of both rolling fatigue and sliding abrasive wear could be found. Based on the results of the accelerated test, a scheme was devised to decrease tappet wear. Wear reduction of the tappet was achieved by using undulated surface topography in the tappet center region. The wear reduction is achieved by trapping of the wear particles in the undulations as well as by increasing the supply of lubricant to the sliding interface.
Condition Monitoring Technology for Plant Machinery System Based on Integrated Wear Monitoring
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 14, issue 2, 1998, Pages 75~81
Condition monitoring technology was applied for an air compressor lubricating system to achieve a proactive maintenance, which could prevent a catastrophic failure and detect root causes of the conditional failure of the system. For this work, various types of wear monitoring technology were used and compared with the results of vibration and temperature measurements. The Results generally showed that every technology has a limitation to failure detection, and integrated-based condition monitoring should be performed for the best results. In this work, an idea for the implementing integrated wear monitoring was suggested and demonstrated.