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.

G. Muthuveerappan

Accurate estimation

CONTACT MODELS

CONTACT RATIO

contact stress

FILLET STRESS

Finite element modeling

Gear ratios

High quality

Load sharing

MODIFICATION FACTORS

Optimum designs

PRESSURE ANGLES

RACK CUTTERS

Reasonable accuracy

SPUR GEAR DRIVES

STRESS LOAD

TIP RADIUS

TOOTH LOAD

TOTAL LOAD

Dentistry

Gear teeth

Model Checking

SPUR GEARS

Stiffness

Stress analysis

finite element method

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IIT Madras

Maximum Fillet Stress Analysis Based on Load Sharing in Normal Contact Ratio Spur Gear Drives

Mechanics Based Design of Structures and Machines

The current computation models for gear contact analysis and wear prediction are mostly based on finite element principles which consumes a lot of computation time and effort. In this paper, an alternate approach of linear complementarity is used for gear contact analysis. This approach was successfully applied for a pair of rigid spur gears in our previous paper. In this paper, we are extending this to a planetary gear train. The linear complementarity problem formulation is revised to take bilateral constraints into consideration. A linear complementarity solver computes the contact forces between meshing teeth of gears in gear train. From the contact forces, sliding wear in gear teeth is predicted. Archard's wear model is used for the wear prediction. © 2019 IOP Publishing Ltd. All rights reserved.

Fulltext

IOP Conference Series: Materials Science and Engineering

Contact analysis of a planetary gear train using linear complementarity

This article presents an idea to remove the inequality in maximum fillet stresses developed between pinion and gear of a step up gear drive. This uniform fillet strength of the gear drive can be achieved by using nonstandard pinion and gear with appropriate addendum modifications generated by nonstandard basic racks of respective tooth thickness not equal to 0.5πm at the pitch circle. The influence of gear parameters such as gear ratio, pressure angle, addendum factor, pinion teeth number, and addendum modifications on the maximum fillet stress on the nonstandard pinion and gears of different tooth thickness has been analyzed through finite element method and finally the optimum value of rack tooth thickness coefficients (kpc and kgc) are suggested for the given gear drive (defined by i) that improves the fillet capacity in bending. This study has been extended for various drives like Sstd, So, S+, and S- drives. © 2015 Copyright Taylor & Francis Group, LLC.

A balanced maximum fillet stresses on normal contact ratio spur gears to improve the load carrying capacity through nonstandard gears

Direct gear design method is one of the most effective gear design approaches, which provides the high performance gears without concern for any predefined tooling parameters. In the present work, the load sharing ratio (LSR) and the corresponding LSR based maximum fillet stresses in terms of non-dimensional stress number have been estimated for the conventionally designed and direct designed symmetric helical gears. It is also extended for direct designed asymmetric helical gears. The area of existence procedure is developed and using the same, the possible existence of design solutions for a drive of required constant transverse contact ratio and different addendum pressure angles is chosen to develop the rack dimensions. Finally, the influence of a few parameters such as gear ratio, transverse contact ratio, top land thickness coefficient and the pinion teeth number on area of existence, load sharing ratio and the corresponding values of non-dimensional stress number in the asymmetric helical gear drives designed through the direct design method has been carried out and discussed. © 2014 Elsevier Ltd.

Mechanism and Machine Theory

Load sharing based maximum fillet stress analysis of asymmetric helical gears designed through direct design - A parametric study

In direct design method, gear pair is selected from area of existence diagram. This area of existence diagram gives N number of possible gear pairs. From this possible gear pairs it is important to optimize the fillet strength of pinion and gear with respect to the optimum profile shift. Optimum design of gear drive means the maximum fillet stresses developed at the pinion and gear are to be equal. Hence the present work attempts for a reasonably accurate estimation of optimum profile shifts based on pinion and gear tooth fillet strength for a load at critical loading point considering the load sharing between the gear pair on asymmetric normal and high contact ratio asymmetric spur gear through direct design. © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

Procedia Engineering

Optimum profile shift estimation on direct design asymmetric normal and high contact ratio spur gears based on load sharing

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.

Applied Mechanics and Materials

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

Because of the lower dynamic load, the noise level during operation and the demand for lighter and smaller automotive transmissions, helical gears have become the subject of attention. The three-dimensional way of calculating the root stresses of helical gears gives realistic results. This paper explains about the geometry of helical gears by simple mathematical equations, the load distribution for various positions of the contact line and the stress analysis of helical gears using the three-dimensional finite element method. A computer program has been developed for the stress analysis of the gears. Root stresses are evaluated for different positions of the contact line when it moves from the root to the tip. To check the validity of the present program, the changes in the trend of the maximum root stress values at various places of the tooth along the face width have been compared with the experimental results from other literature. A parametric study is made by varying the face width and the helix angle to study their effect on the root stresses of helical gears. Based on this investigation the effect of helix angle and face width on the root stresses of helical gears has been clarified for different positions of the contact line. © 1994.

Computers and Structures

Finite element modelling and stress analysis of helical gear teeth

Finite element modelling and the analysis of a straight bevel gear tooth is carried out to evaluate the bending stresses. An isoparametric brick element is used for finite element analysis. The stress distribution obtained at the root of the tooth is compared with the experimental results available in the literature and the tooth behaviour at the root is studied by changing the various parameters such as torque, pressure angle, shaft angle, rim thickness and face width of the gear pair. This paper also discusses the load distribution on the face of the tooth as well as the variation of load in magnitude and position as the tooth rotates. © 1993.

Finite element modelling and analysis of a straight bevel gear tooth

Effect of addendum on contact strength, bending strength and basic performance parameters of a pair of spur gears

Journal of Tribology

Finite Element Analysis of High Contact Ratio Spur Gears in Mesh

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science

The torsional stiffness of involute spur gears

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

Journal	Mechanics Based Design of Structures and Machines
ISSN	15397734
Open Access	No