Milosav Ognjanović

Decisions in gear train transmission design

The main objective of this paper is a practical and useful approach to problem solving in decision making, by an intelligent computer program. The existing theoretical considerations of this problem are not sufficient for practical application, due to the complexity of this subject, numerous related influences, insufficient data, etc. The aim of this paper is to present a structure for decision making in gear train transmission design, to determine the correlation between decisions in this process and to propose a method for their realization.

Design Process for Pressure Housing of Power Systems

Summary The design process of any technical system is based on well-elaborated procedures which lead, step by step, from the idea to the final product. For highly specialized products, such as power systems, this procedure contains some specific details \[1]. There are certain unique operations and activities, with specific constraints, leading to the result of a design process. In this paper the design process of power systems is presented as a set of appropriate models which make possible the evolution of these systems by linked software procedures and reflect themselves on the design process too. Apart from that, they represent the example of transformation of the design process into a form suitable for realization by software systems.

Some Approaches to Machine Parts Modelling Using CAD Software

CAD software is a universal design tool for geometric shape representation, variation of formed shapes and their positions, computation, analysis, and production of such objects. The main objective of this paper is to suggest more effective methods for machine parts modelling using CAD software. This analysis refers to the design phase in which abstract functions have to be transformed into concrete machine parts shapes. Machine parts are classified according to the modelling capability of each part. All discussions and representations refer to three-dimensional models, which are obtained by using existing commercial CAD programs. The main characteristics of the applied software are described in general.

Gear System Reliability-Based Design of Gear Drive Units

In the field of Engineering Design various methods are established for technical systems development. Gear transmission units are really a complex structure with various indicators of their behavior, such as the level of reliability, vibration and sound level, etc. This article contains the application of property-based design approach to gear unit reliability system structuring, and then the application of elementary reliability as a design constraint in design parameters definition. A specific way for elementary reliability and system reliability is introduced. Robust and axiomatic design of gear unit components is adapted for design parameters definition.

Bearings Failure of Gear Drive Unit Caused by Gear Resonance

Gear transmission units could work properly in the resonance conditions but they cause very unfavorable effects on other components and the environment. It is necessary to identify the resonance range, and afterwards to harmonize design parameters with operating conditions, so as to avoid primary and secondary resonance. This article presents the procedures for gear resonance identification and its influence on rapid failure of bearings and other gears of bucket wheel excavator drive’s gearbox, entitled SRs-1301. Thereafter follows the correction of design parameters of critical gear pair in order to avoid its resonance and excitation of natural frequency of gearbox housing. Besides the analysis of dynamic behavior of gears, this article provides FEM analysis of stiffness of gearbox components and modal analysis of gearbox housing. Applying new parameters, calm work of gearbox is obtained, and life cycle of bearings suits service load.

Failure Probability of Gear Teeth Wear

Gear load capacity calculation is defined according to pitting of the teeth flanks. In service conditions, a failure process is combined of a number of damage processes. Which of them will be dominant depends on design parameters, technological and exploitation conditions. Periodically, for some of gears, extremely difficult service conditions exist, which creates a possibility for progressive teeth wear. Results of progressive wear are obtained by experiments. For these results, failure boundaries which can be used for parameters of Weibull’s function definition, for different stress levels and for different stress cycles numbers (teeth mesh revolutions) have been defined.