Milan Banić

RADIAL FORCE IMPACT ON THE FRICTION COEFFICIENT AND TEMPERATURE OF A SELF-LUBRICATING PLAIN BEARING

Self-lubricating bearings are available in spherical, plain, flanged journal, and rod end bearing configurations. They were originally developed to eliminate the need for re-lubrication, to provide lower torque and to solve application problems where the conventional metal-to-metal bearings would not perform satisfactorily, for instance, in the presence of high frequency vibrations. Among the dominant tribological parameters of the self-lubricating bearing, two could be singled out: the coefficient of friction and temperature. To determine these parameters, an experimental method was applied in this paper. By using this method, the coefficient of friction and temperature were identified and their correlation was established. The aim of this research was to determine the effect of radial force on tribological parameters in order to predict the behavior of sliding bearings with graphite in real operating conditions.

Recommendations for the estimation of the strength of the railway wheel set press fit joint

Although press fit joints are very important in railway engineering, few authors have investigated the strength of press fit joints in terms of their application in railway vehicles. This study analyses the tribological parameters that influence the strength of press fit joints, especially the contact pressure and the static friction coefficient. This research was targeted towards the control of the friction coefficient value to obtain the required strength of a press fit joint in conditions close to the minimum contact pressure that results in less prestressed press fit joints. To estimate press fit joint strength, this study examines the use of minimum and maximum values of the friction coefficient as recommended in the literature considering wide tribological conditions, as well as the experimentally determined friction coefficient values for specific tribological conditions. The study also points out the discrepancy between current railway standards and engineering practice considering the inspection of wheel set press fit joint strength.

Load Capacity of Cylindrical Worm Gears According to DIN 3996-2012

A worm drive is widely used in power and movement transmission, and the proper functioning of the entire machine system depends on it. The advantages of a worm drive, compared to other types of drives, are primarily reflected in its compact design, large transmission ratio, reliability, the possibility of vibration damping, as well as in structural advantages regarding branching and summarising energy, etc. Its capacity is limited by the emergence of a larger number of boundary conditions when in exploitation. This paper considers load capacity calculations of worm gears according to DIN 3996-2012.

DETERMINATION OF RESIDUAL STRESS IN THE RAIL WHEEL DURING QUENCHING PROCESS BY FEM SIMULATION

Residual stresses of the rail wheels are influenced by heat treatment during the manufacturing process. The quenching process during the manufacturing results in the residual stresses within the rail wheel that may be dangerous for the rail wheel during its operation. Determination of the residual stress in the rail wheel is important for understanding the damage mechanisms and their influence on the proper work of rail wheels. This paper presents a method for determining the residual stresses in the rail wheel during the quenching process by using the directly coupled thermal-structural analysis in ANSYS software.

Importance And Role Of Competence In Professional Career Of Product Develop Engineers

Abstract Product development is a creative task where is systematically created a new product, which makes possible to firms to offer attractive, innovative and market oriented products. In conditions of fierce competition and saturated markets, companies that do not innovate are stagnating and disappear from the market. Innovation is therefore every intervention which can reduce production costs, enables optimum utilization of available human, energy and material resources, improve product quality, improve the placement, which leads to an increase in competitiveness. A prerequisite for fulfillment of the above-mentioned tasks is that the companies have engineers with the appropriate competencies, which are able to, through creativity, innovation and fascinating technique of creating new or improving existing products and lunch it on the market. The paper discusses the role and importance of the competences that are necessary for a successful professional career of product development engineers.

Load Capacity of Worm Gears

Worm gearing has very wide use in power transmission in movement and the correct work of the complete machine system depends on it. Latest research in this area shows that there may be a large number of limited states in its work which are identified on the basis of the state of working surface. This paper considers these limited states and gives a critique of load capacity calculation.

The New Engineering Education Model on University of Niš

The engineer must be able to present his work and his position, to defend his opinion and to record it in written form. Therefore, engineers, educated on universities, have to be capable to work with experts from other disciplines in order to take advantage of new technologies and to use them in environmentally friendly products and production processes. This paper presents the university education model in the field of product development.

Crossed Helical Gears with Wheels Manufactured from Sintered Steel with Pyrohydrolysis

Crossed helical gears are used in cars and many household appliances. The trend towards increased comfort in motor vehicles has led to the utilization of more than a hundred servo-drives in luxury class automobiles. Key advantages of crossed helical gears are their simple and inexpensive design, good noise performance and high ratios that can be realized in one step. Sintered steel is a highly favorable material for wheels in crossed helical gears. They are able to satisfy high performance demands in the areas of wear, fretting, tooth fracture and pitting load capacity. This report describes the results of an examination into the use of the iron-based sintered material Fe1.5Cr0.2Mo with pyrohydrolysis in crossed helical gears, in the areas of wear resistance and other damage types under different speeds and loading conditions.