Determination of the ISO face load factor in spur gear drives by the finite element modeling of gears and shafts

Precise modeling of arc tooth face-gear with transition curve

Generalised non-dimensional multi-parametric involute spur gear design model considering manufacturability and geometrical compatibility

Purpose – The purpose of this paper is to investigate the effect of pressure angle, and module of spur gear teeth on stress concentration factor, using photoelasticity method, and numerical MSC/NASTRAN finite element package.Design/methodology/approach – The stress concentration factor is determined as a ratio between maximum stress (determined in the fillet radius by photoelastic and finite element methods), and nominal stress (calculated by a common standard formulas). In order to specify the geometric parameters (height and thickness) of gears, both standard Deutsches Institut fur Normung (DIN)/Japanese Gear Manufactures Association (JGMA), and five other non‐standard approaches are used.Findings – The results show that the stress concentration factor increases by decreasing the pressure angle. In addition, the values which are obtained by finite element analyses exhibit more uniformity than photoelastic method.Practical implications – An accurate determination of stress concentration factors will limi...

The pressure angle effects of spur gears on stress concentration factor

Combined Effects of Lead Crowning and Assembly Deviations on Meshing Characteristics of Helical Gears

In this study, attempts are carried out to determine the amount of stress at the fillet radius region of spur gears when the applied load location changes, along the involute curve, from the top surface to the bottom. For this purpose the photoelastic method and numerical MSC/NASTRAN software are used. The gears with pressure angle (ϕ) 20o, and 25o were prepared from photoelastic material type PLM-4B in this study. Practical calibration is used to determine the fringe order value of this material. Four different modules (m); 6, 10, 14, and 20 mm were prepared for two different numbers of teeth (N); 18 and 26, with different face widths (B1, B2, B3); 10, 17, 25.4 mm respectively. Four load values were applied on each tooth at five to six different load locations along the involutes curve profile. In order to accomplish the comparison between the results for different methods, the same sample dimensions and parameters were prepared again for the MSC/NASTRAN software.



The results showed that the maximum applied stress at the fillet radius occur when the applied load location is on the top land of a tooth, and then that amount is decreased when the applied load positions change toward the bottom land. The results of the NASTRAN method showed that the applied stress at the fillet radius would be minimum when the loading point locates between the pitch circle and dedendum circle, in particular around 1.5 times module (1.5 m) of the total tooth height which equals 2.25 module, and then the applied stresses are increased again. However, in the photoelastic method the applied stresses were decreased continuously to the bottom land. The reasons behind such results can be attributed to the type of failure theories that can be used in NASTRAN software for characterization the applied stresses, i.e. considering types of applied stresses into account, such as bending, direct compressive, and shear stresses. Moreover, in order to compare the applied stress values at fillet regions, obtained by theoretical and practical approaches, four different standard mathematical equations are used for stress calculation at fillet radius of spur gears to show the difference of the parameters and variables that can affect the applied stress results.

N. M. Ahmed

Papers

Effect of the load location along the involute curve of spur gears on the applied stress at the fillet radius