The aim of this paper is to investigate the influence of pressure angle on drive and coast sides in conventional design asymmetric normal contact ratio spur gear, considering the load sharing between the gear teeth pair. The multi pair contact model in finite element analysis is used to find the load sharing ratio and respective stresses. It has been found out that the predictions through multipoint contact model are in good agreement with the available literature. A unique Ansys parametric design language code is developed for this study. It is found that, the maximum fillet stress decreases up to the threshold point for drive side (35o) and coast side (25o) pressure angles, beyond this point it increases. The load share based maximum fillet and contact stresses are lower in the high pressure angle side than that of the low pressure angle side, when it is loaded at the critical loading points. © (2014) Trans Tech Publications, Switzerland.

G. Muthuveerappan

ANSYS parametric design language

CONTACT MODELING

contact stress

Conventional design

CRITICAL LOADING

Load sharing

Multi-point contacts

SPUR GEAR DRIVES

End effectors

finite element method

Industrial engineering

SPUR GEARS

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Applied Mechanics and Materials

Influence of pressure angle on load sharing based stresses in asymmetric normal contact ratio spur gear drives

An optimum design of high-quality gears requires an accurate estimation of the tooth load. Since only a fraction of the total load is shared by each pair, when there is contact in more than one pair during transmission, the same has been estimated with a reasonable accuracy through the load-sharing ratio calculated using the single-point loaded model. The reliability of this method has also been justified by comparison with multipair contact models and also by checking with the values available in the literature. The influence of finite-element modeling, boundary conditions, gear ratio, teeth number, module, pressure angle at pitch circle, backup ratio, generating rack cutter tip radius, and addendum modification factor on the load-sharing ratio and in turn in the maximum fillet stress has been studied and discussed using single-point loaded model of normal contact ratio gear pairs in this study. 2010 Copyright © Taylor & Francis Group, LLC.

Mechanics Based Design of Structures and Machines

Maximum fillet stress analysis based on load sharing in normal contact ratio spur gear drives

In a given size of symmetric involute gear designed through conventional approach, as the load carrying capacity is restricted at the higher pressure angle due to tipping formation, the use of the asymmetric toothed gear to improve the fillet capacity in bending is examined in this study. Non-standard asymmetric rack cutters with required pressure angles and module are developed to generate the required pinion and gear of a drive with asymmetric involute surfaces and trochoidal fillet profiles. The respective profiles thus generated are optimized for balanced fillet stresses that are equal and possibly the lowest also. For this study of optimization, several non-standard asymmetric rack cutters are designed to accommodate different combinations in the values of pressure angle, top land thickness ratio, profile shift, speed ratio and the asymmetric factors. However for any drive with a given center distance and a speed ratio, only two non-standard asymmetric rack cutters, one for the pinion and other for the gear are used to generate a required numbers of pinion and gear with different cutter shift values for the purpose of optimization. The influence of these parameters on the maximum fillet stress has been analyzed to suggest the optimum values of these parameters that improve the fillet capacity in bending. The optimization of the asymmetric spur gear drive is carried out using an iterative procedure on the calculated maximum fillet stresses through FEM for different rack cutter shifts and finally the optimum values of rack cutter shifts are suggested for the given center distance and the speed ratio of an asymmetric gear drive. Comparisons have also been made successfully with the results of the AGMA and the ISO codes for symmetric gears to justify the results of the finite element method pertaining to this study. © 2007 Elsevier Ltd. All rights reserved.

Mechanism and Machine Theory

Optimization of asymmetric spur gear drives to improve the bending load capacity

Two procedures to optimize a given asymmetric gear drive have been developed through direct gear design method. Considering several sets of the addendum pressure angles of pinion and gear for a required contact ratio, first the nonstandard rack cutters and subsequently the asymmetric tooth profiles of pinion and gear are generated for each set. FEM analysis has been carried out to determine maximum fillet stress in pinion and gear at each set. The set of profiles that develops an equal and possible lowest minimum of the maximum fillet stress at its respective fillet is considered as the optimum one for a maximum load carrying capacity. In this connection, the influence of speed ratio, asymmetric factor, number of teeth, and center distance on the maximum fillet stress is also studied.

Optimization of asymmetric spur gear drives for maximum bending strength using direct gear design method

JSME International Journal Series C

Bending Load Capacity Enhancement Using an Asymmetric Tooth Profile

Journal	Applied Mechanics and Materials
ISSN	16609336
Open Access	No