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The increased demands for driver comfort and stringent pollution control measures have resulted in a revival of planetary gearboxes for road applications, due to their possibility to change the transmission ratio under load in synchronism with engine operation. Modern boxes provide as many transmission ratios as possible from the least possible number of simple component planetary gear trains (PGTs) by providing links between elements of multiple component PGTs. The application conditions decide to prioritize either the maximum number of transmission ratios, or ruggedness and reliability. Power circulation, hollow shafts, or complex planet carrier arrangements are avoided if possible. This paper deals with multispeed complex PGTs composed of at least two interconnected simple component PGTs controlled by brakes and clutches. Several variants of complex PGTs and the placement of brakes and clutches on external shafts of the gear trains are examined, and the transmission ratio functions derived. The kinematics of multi speed gear trains are obtained as combinations of two or more two-speed gear trains. An analysis of several contemporary gearbox layouts is provided together with the transmission ratio functions, together with an overview of the procedure for the calculation of creation of multi-speed gear trains is given. [ABSTRACT FROM AUTHOR]

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During operation, it is essential to know theoperating temperature of the bearing in order to determine the thermal stability of the sliding bearing. This paper presents results of measuring the operating temperature of the sliding bearing using FLIR camera, on the testing table in the Laboratory of Applied Mechanics and Mechatronics, in Mechanical Engineering Faculty in East Sarajevo. Experimental results are presented ona diagram, followed by their comparison with the values of the operating temperature obtained analytically. Based on the operating temperature obtained through experiments and analytical calculation, thermal stability of the sliding bearing hasbeen tested. [ABSTRACT FROM AUTHOR]

During exploitation motor vehicle gearboxes are exposed to varying conditions. The changes are stochastic and dependent on many factors. These changes directly affect also to the gearboxes damage, and therefore the gears damage. Different types of damage can occur on gears, so that this paper will give focus on the damage on gears. According to DIN 3979 over 20 types of damage appearing on gear are given, while in this paper only damages on gears that are in gearboxes embedded will be presented. The paper contains the results of the damage percentage of manual gearboxes and the results of cumulative damage of manual six-speed gearboxes. [ABSTRACT FROM AUTHOR]

Before analysis, development or improvement of existing structure of drive unit or gearboxes, the load that appearing in exploitation must be known. This paper presents a method of load (torque) measurement, on the cardan shaft embedded in the freight vehicle, using strain gages. The aim of the study is to determine torque variation depending on the exploitation conditions (road surface, speed transmission, vehicle load, etc). The measurement was performed for different road characteristics (vehicle movement on flat terrain, up and down the slope). Results are presented using tables and diagrams, and percentage utilization of the power drive unit, embedded into freight vehicle, was calculated based on obtained values of torque. Obtained results have an important role for designers because they give a general insight in the load on the cardan shaft, which represent the basis for future development or redesign of power unit or gearboxes and basis for forming of specter of gear load and bearing embedded into gearbox. [ABSTRACT FROM AUTHOR]

The paper represents a solution example of a specific engineering problem using thermo-mechanical analysis. The paper provides theoretical basis of numerical solving the problem of heat conducting through continuum using the finite element method. Calculation of heat conducting using the finite element method determines the temperature field used as an input for thermo-mechanical calculation. The basic task of thermo-mechanical calculation was the identification of the cause of cracks on the powder material transport wagon. After the analysis of the wagon crack causes, repair of the cracks is suggested. Repeating of the FEM analysis on the reconstructed model confirms that the wagon satisfies the criteria of static and fatigue strength appointed by the standards. [ABSTRACT FROM AUTHOR]