An investigation of tribological behaviors of dynamically loaded non-grooved and micro-grooved journal bearings (original) (raw)
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Tribology International, 2011
Performances of plain and micro-grooved engine journal bearings were investigated in this study. Numerous experiments were performed under different static loads by using the purpose-built journal bearing test rig. Micro-grooves were made by cutting micro-channels both around and across the engine journal bearing surfaces. Stribeck curves for the micro-grooved and the plain journal bearings were then experimentally and theoretically generated while frictional torque versus angular velocity curves were also plotted. The results showed that the highest value of coefficient of friction as well as the frictional torque was obtained on the transversal micro-grooved journal bearings.
International Journal of Engineering Research and
In this study, performances of engine bearings with microgrooved circumferentially, transversally and as herringbone (Vshaped) on their surfaces were investigated under dynamic loading conditions both experimentally and numerically. The frictional force resulted from the applied dynamic load on the bearings was determined experimentally by using a developed frictional force measuring device. Finally, the results of performances of the microgrooved bearings and those of plain bearings were compared and presented.
Lubricants, 2020
Optimizing the surface topography of cast iron crankshafts offers the opportunity to use this material as an alternative to steel in high-performance combustion engines. In the past, this was not possible due to the higher wear on bearing shells and the higher friction losses in relation to forged steel shafts. In order to find an optimized shaft micro topography, the friction and wear behavior of steel and cast iron shafts with different surface treatments were compared to each other, using a combined physical (experimental) and a virtual (computational) simulation approach. The experiments were carried out with a rotary tribometer using a journal bearing test configuration with the possibility to test real-life bearing shells and shaft specimens, manufactured from real-life crankshafts. In the experiments, a polished steel shaft with low bearing wear was effective. The optimization of cast iron crankshafts by a novel surface treatment showed a significant reduction of bearing wear...
Effect of cylindricity on the tribological performance of heavily loaded slow-speed journal bearing
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2014
Theoretical and experimental studies have been conducted to analyze the effect of cylindricity on performance of a heavily loaded slow-speed journal bearing. The design of experiments has been employed to quantify the effect of bearing clearance and cylindricity on the wear. Since the initial experimental results did not establish any definitive trend, the effect of running-in was considered and the sliding distance required for reaching steady wear was estimated by conducting tests on lubricity tester employing conformal block and disc configuration. Further experiments incorporating the running-in were then conducted on journal bearing test rig. The wear coefficient was determined using the steady wear data obtained experimentally on the lubricity tester. A mathematical model was formulated to estimate wear of the bearing incorporating the actual cylindricity. The theoretical and experimental results corresponded well indicating a strong dependence of wear on the bearing cylindricity at the contact zone.
Journal of Tribology, 2009
Recently, herringbone-grooved journal bearings (HGJBs) have important applications in high-speed rotating machinery. The groove action in pumping the lubricating fluid inward generates supporting stiffness and improves the stability of the bearing when operating concentrically. Several researchers have investigated the static and dynamic characteristics of HGJBs and grooved thrust bearings. Most of these investigations were theoretical and concentrated on HGJBs with rectangular-profile grooves. In the present work, the static and dynamic characteristics of the beveled-step HGJBs are experimentally investigated. The bearing attitude angle, pressure distribution, and bearing friction torque were measured on a hydrodynamic lubrication unit, and then the static and dynamic characteristics were determined. The obtained experimental results are compared to the obtained experimental results for plain journal bearing. The merits as well as the demerits of the groove profile were discussed through comparisons with plain journal bearings.
Determination of friction coefficient in journal bearings
Materials & Design, 2007
Knowing friction coefficient is important for the determination of wear loss conditions at journal bearings. Tribological events that influence wear and its variations effect experimental results. In this study, friction coefficient as example at bronze radial bearings has been determined by a new approach. In experiments, friction effects of bearings have been examined at dry and lubricated conditions and at different loads and velocities.
IJRASET, 2021
Proper lubrication of mechanical components is very important for the reliable efficiency and useful life. The working temperature of the components can affect the lubricating oil and can degrade the lubricating characteristics of oil. This paper presents the experimental investigation on tribological behaviour of journal bearing material. Two types of additives are used in lubricating oil i.e., powder and granular types of additives. The investigation is carried out on pin-on-disc apparatus to determine the wear and coefficient of friction. The statistical analysis is performed using design of experiments and Taguchi robust design to determine the optimum parameters of lubricating additives. It is found that for constant speed of 400 rpm with 5% concentration with varying size the granular lubrication have lower values than powder lubrication for all load conditions
Steady state and dynamic characteristics of axial grooved journal bearings
2009
The steady state and dynamic characteristics including whirl instability of oil journal bearings with single axial groove located at the top of the bearing and then at some angular interval from the top from which oil is supplied at constant pressure are obtained theoretically. The Reynolds equation is solved numerically by finite difference method satisfying the appropriate boundary conditions. The dynamic behaviour in terms of stiffness and damping coefficients of fluid film and stability are found using a first-order perturbation method for each location of the groove. It has been shown that both load capacity, end flow is maximum when the feeding groove is at 121 location and thereafter the load capacity falls, stability improves for smaller groove angle and groove length at higher value of eccentricity ratio and speed. The stiffness and damping coefficient magnitude is found to be higher for the bearing with smaller groove angle and groove length, the difference between the hydrodynamic and hydrostatic load increases at 121 groove location.