Catia Customization for Design and Modeling of Two Stage Spur Gearbox

In this paper, we describe how the customization of design task, in solid modeling with CATIA V5 for two stage spur gearbox can be approached, by means of macros (piece of code) and with GUI form. The user has to supply some basic requirements of the gearbox and rest of the different parameters for design of gearbox is calculated by formulas. And then with the help of these parameters, part model of gearbox is created.

Applications of Ceemdan in Dynamic Behavior of Defected Spur Gearbox Running Under Acyclism Regime

ABSTRACTEmpirical Mode Decomposition (EMD) and its approaches are powerful techniques in signal processing especially for the diagnosis of rotating machinery running in non-stationary regime. We are interested in this paper to the dynamic behavior of a defected one stage gearbox equipped with an elastic coupling and loaded under acyclism regime generated by a combustion engine. Actually, we adopt an approach to the EMD method called Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) as a technique to perform the diagnosis of the studied system. Since the obtained signals are modulated, all obtained Intrinsic Mode Functions (IMFs) are modulated and are processed and shown by the Wigner-Ville distributions (WVD) as well as the spectrum of their envelope in order to detect defects such as cracked tooth defect in the wheel of the spur gearbox and eccentricity defect in the gear.

Design of spur gearbox shafts for fatigue Fatigue Design of Spur Gearbox Shafts

Spur gearboxes are used in machine drives to transfer torque from the engine to the machine’s working element: the driving wheel of the car, the rotor of the helicopter or the drum of the conveyor. Spur gears and bearings are mounted on the shafts of the gearbox. Under the action of torque and forces in the gearing of the wheels, tangential and normal stresses occur in the cross section of the shaft. Normal stress varies in a symmetrical cycle and leads to material fatigue. In view of this, a mathematical model is proposed to improve the accuracy of calculating the overall safety factor for shaft fatigue resistance. Based on the von Mises deformation theory, equivalent stress parameters (amplitude and the mean) are determined. To assess the safety margin of the shaft, Soderberg, Goodman, Gerber, and ASME criteria are used. The stress amplitude margin is calculated depending on the endurance limit of the shaft material, refined according to the specified conditions. The average stress margin is determined relative to the yield strength of the material or the ultimate strength. Formulae for calculating the overall safety factor of amplitude and average stress are obtained. With a known safety factor and load, it is possible to determine the shaft diameter at the preliminary design stage of the gearbox according to the fatigue resistance condition.