R.Prabhu sekar - Academia.edu (original) (raw)
Papers by R.Prabhu sekar
The surface tooth wear which occurs at the gear contact region due to inadequate contact strength... more The surface tooth wear which occurs at the gear contact region due to inadequate contact strength of the tooth is one of the predominant modes of gear failures. Currently, higher contact ratio spur gears are increasingly used in power transmission applications such as aircraft, wind turbine, automobiles and compact tracked vehicles due to their high load carrying capacity. In this work, the direct design is found to be one of the efficient gear design methods to reduce the tooth surface wear on high contact ratio asymmetric spur gears. Asymmetric gear tooth is defined, as one whose tooth geometry of the drive and coast sides is not symmetric. Asymmetry between tooth sides is achieved by providing two different pressure angles at the respective coast and drive side pitch circles. The area of existence diagrams for normal and high contact ratio gears have been developed to select suitable design solution with the given variables of gear ratio, contact ratio and teeth number. The conta...
Teeth Wear Enhancement Along the Tooth Profile of Spur Gear Drive by Balancing the Fillet Stress Through Positive Correction Factor
Advances in Simulation, Product Design and Development, 2019
This article suggests a modification in the correction factor which will improve the wear resista... more This article suggests a modification in the correction factor which will improve the wear resistance for the equalized fillet stress in spur gear drive. As ruled, higher transmission proportional drives have an altering stresses in the fillet of pinion and the wheel. This fillet stress can be equalized by utilizing addendum alteration system. This changed addendum can bring down the fillet stress in the pinion subsequently enhancing the load conveying limit of the drives. Here, the fillet stress is assessed utilizing finite element analysis (FEA) technique for various blends of S+ drives. This correction factor is given in the pinion; wheel with the end goal that the bending strength of the drive is improved. At last, the fillet stress is equalized by varying the correction factors for every one of these drives, and the upgraded estimation of balanced strength with enhanced wear resistance is recommended for the spur gear drive.
Journal of Solid Mechanics, 2020
The surface tooth wear which occurs at the gear contact region due to inadequate contact strength... more The surface tooth wear which occurs at the gear contact region due to inadequate contact strength of the tooth is one of the predominant modes of gear failures. Currently, higher contact ratio spur gears are increasingly used in power transmission applications such as aircraft, wind turbine, automobiles and compact tracked vehicles due to their high load carrying capacity. In this work, the direct design is found to be one of the efficient gear design methods to reduce the tooth surface wear on high contact ratio asymmetric spur gears. Asymmetric gear tooth is defined as one whose tooth geometry of the drive and coast sides is not symmetric. Asymmetry between tooth sides is achieved by providing two different pressure angles at the respective coast and drive side pitch circles. The area of existence diagrams for normal and high contact ratio gears have been developed to select suitable design solution with the given variables of gear ratio, contact ratio and teeth number. The conta...
Effect of Module on Wear Reduction in High Contact Ratio Spur Gears Drive Through Optimized Fillet Stress
The current study intends to predict the wear obstruction of high contact ratio spur gears over o... more The current study intends to predict the wear obstruction of high contact ratio spur gears over optimized fillet stress between the wheel and pinion. As the fillet region of the wheel is considered to be the critical region with high stress concentration, it becomes essential to study the wear depth at this enhanced bending strength. The optimization of fillet stress is carried out through profile modification technique and the tooth wear of the gear drive is examined using contact analysis and analytical method by taking in the tooth load distribution at the contact points, fillet stress and strength during contact for various work cycles. This examination additionally investigates the impact of module over depletion of material from the tooth surface of the transmission system and lastly the outcomes are conferred that the reduced stress for the high contact ratio gear drive has enhanced wear resistance.
Tooth root crack is considered as one of the crucial causes of failure in the gearing system and ... more Tooth root crack is considered as one of the crucial causes of failure in the gearing system and it occurs at the tooth root due to an excessive bending stress developed in the root region. The modern power transmission gear drives demand high bending load capacity, increased contact load capacity, low weight, reduced noise and longer life. These subsequent conditions are satisfied by the aid of precisely designed asymmetric tooth profile which turns out to be a suitable alternate for symmetric spur gears in applications like aerospace, automotive, gear pump and wind turbine industries. In all step up and step down gear drives (gear ratio > 1), the pinion (smaller in size) is treated as a vulnerable one than gear (larger in size) which is primarily due to the development of maximum root stress in the pinion tooth. This paper presents an idea to improve the bending load capacity of asymmetric spur gear drive system by achieving the same stresses between the asymmetric pinion and g...
Estimation of loss factor based on the load share model in improved bending strength spur gear drive system
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology
This paper demonstrates the prediction of loss factor for non-standard gear drives with equal str... more This paper demonstrates the prediction of loss factor for non-standard gear drives with equal stresses in the root region of the pinion and wheel. This implementation of equal stresses in the root region is achieved in the described model of a spur gear drive with higher transmission ratio using non-standard rack cutter. The aim is to discover the optimal modification point in the tooth profile by varying values of tooth thickness with at most balanced stresses in the gear pair considered for the study. A loss factor is predicted along the path of contact for a complete meshing cycle using finite element method. This paper studies and compares the distinct models and thereby identifies the suitable and appropriate models. The predicted loss factor includes the distribution of load sharing effect during the meshing which is excluded in the compared models. The gear pair is analyzed, and the loss factor is predicted for influence over the major drive parameters. It was observed that t...
Journal of Mechanical Engineering and Sciences
As lined, higher transmission ratio drives system will have uneven stresses in the root region of... more As lined, higher transmission ratio drives system will have uneven stresses in the root region of the pinion and wheel. To enrich this agility of uneven stresses in normal-contact ratio (NCR) gearing system, an enhanced system is desirable to be industrialized. To attain this objective, it is proposed to put on the idea of modifying the correction factor in such a manner that the bending strength of the gearing system is improved. In this work, the correction factor is modified in such a way that the stress in the root region is equalized between the pinion and wheel. This equalization of stresses is carried out by providing a correction factor in three circumstances: in pinion; wheel and both the pinion and the wheel. Henceforth performances of this S+, S0 and S- drives are evaluated in finite element analysis (FEA) and compared for balanced root stresses in parallel shaft spur gearing systems. It is seen that the outcomes gained from the modified drive have enhanced performance th...
IOP Conference Series: Materials Science and Engineering
Gear loss factor is one of the imperative parameter in estimating the power loss in a meshing gea... more Gear loss factor is one of the imperative parameter in estimating the power loss in a meshing gear pair. This paper demonstrates the prediction of gear loss factor parameter in spur gear drive using the load distribution technique. The aptness of two distinct contact ratios is studied and compared in this paper: Normal Contact Ratio (NCR) and High Contact Ratio (HCR). The described model is studied for gearing strength which is improved through profile modification technique. The ultimate focus is to enhance the gearing strength of the pinion in a spur gear drive by discovering the optimal modification point in the tooth profile with at most balanced stresses in the gear pair considered for the study. Using contact analysis, the stresses developed over the contracting surfaces are predicted through finite element method and it is balanced between the gear and pinion. A gear loss factor is predicted along the path of contact for a complete meshing cycle for this balanced drive. It is...
Influence of gear ratio on wear depth of nonstandard HCR spur gear drive with balanced fillet stress
Materials Today: Proceedings
Abstract In this paper, the wear depth of a nonstandard High Contact Ratio (HCR) spur gear drive ... more Abstract In this paper, the wear depth of a nonstandard High Contact Ratio (HCR) spur gear drive is investigated using contact analysis considering the load share between the tooth in contact, fillet stress and contact stress for number of mesh cycles in steel gears. The fillet stresses obtained using finite element method is balanced by varying the tooth thickness along the reference line. This method of changing the tooth thickness is referred as nonstandard HCR spur gear drive. Using this method, an improved nonstandard HCR spur gear drive is obtained in terms of bending strength. In this enhanced nonstandard HCR spur gear drive the wear depth is estimated analytically for balanced fillet stress. Also, this paper explores the influence of gear ratio over wear depth of nonstandard HCR spur gear drive and finally the results are discussed.
Performance enhancement of spur gear formed through asymmetric tooth
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology
Tooth fracture and surface wear are the major failure causes in a gearing system. With increasing... more Tooth fracture and surface wear are the major failure causes in a gearing system. With increasing demand for high power density gear applications, the need of effective gear design becomes an important requirement to improve gear life. This article presents a method to enhance the load carrying capacity in bending and contact, as well as wear resistance to increase gear efficiency through asymmetric tooth. Asymmetric gear is the one whose pressure angles at pitch circle on drive and coast sides are different. In the present investigation, the load shared by a teeth pair, fillet and contact stresses, wear resistance, frictional power losses and the respective mechanical efficiencies have been determined for comparative performance assessment of symmetric and asymmetric spur gears.
Evolution of balanced root stress and tribological properties in high contact ratio spur gear drive
Mechanism and Machine Theory
Abstract Tooth bending and surface wear are the two major causes of failure modes which occur due... more Abstract Tooth bending and surface wear are the two major causes of failure modes which occur due to inadequate bending and contact strength. In a gear drive, when the gear ratio is more than one the bending strength of the pinion and gear it is different. Consequently gear drive with an equivalent bending strength in the gear and pinion is called as a balanced gear drive. This can be attained by providing non-standard tooth thickness at the pitch circle in High Contact Ratio (HCR) spur gears. Non-standard HCR spur gear drive is one in which the tooth thickness at the pitch circle of the gear and pinion is not same. In the present study, tooth wear over the contacting surfaces for non-standard HCR spur gear drive is probed numerically through finite element analysis (FEA). In addition, the tooth load, contact stress, film thickness and sliding distance are also estimated for a balanced non-standard HCR spur gear drive. Also the effect of different gear parameters like pinion teeth number, pressure angle, addendum height and gear ratio on tooth wear along the line of action on non-standard HCR spur gear has been evaluated and discussed.
A mixed finite element and analytical method to predict load, mechanical power loss and improved efficiency in non-standard spur gear drives
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2017
A reasonably accurate estimation of gear power loss is desirable to maximize gear performance. Th... more A reasonably accurate estimation of gear power loss is desirable to maximize gear performance. The load share by teeth pair, contact stress, sliding speed, elastohydrodynamic film thickness and coefficient of friction are some of the most important contributing factors which determine frictional power losses in gears. This paper presents an improvement concept to minimize the load-related power losses (sliding and rolling power losses), which will lead to an enhancement in gear efficiency by selection of non-standard gears. The tooth thickness at the pitch circle of the pinion and gear is different in non-standard gears (kpπm > 0.5 πm and kgπm
Enhancement of Wear Resistance on Normal Contact Ratio Spur Gear Pairs through Non-Standard Gears
Wear, 2017
Abstract Tooth wear is considered to be one of the major causes of failure modes in gearing syste... more Abstract Tooth wear is considered to be one of the major causes of failure modes in gearing systems. The achieved service life of the geared unit mainly depends on the gear tooth strength and surface wear. Excessive wear is characterized by loss of tooth profile, which results in high noise and vibration, a minor loss of conjugate action and a reduction in efficiency. Hence, enhancement of gear life against wear becomes an important requirement for effective design detailing of gears. This article presents an idea to minimize the wear of the gear teeth by adopting non-standard gear. Non-standard gear is defined as one whose tooth thickness at the pitch circle is not equal to 0.5πm. In this study, the impact of the tooth thickness coefficient on tooth wear for standard and non-standard spur gears is numerically investigated. The non-standard tooth thickness in the pinion leads to enhancement of the tooth strength and leading to reduction of tooth wear. Finally, the influence of gear parameters such as gear ratio, pressure angle and pinion teeth number on wear depth, for non-standard pinion and gear has been investigated and the results of the parametric study are discussed.
Estimation of tooth form factor for normal contact ratio asymmetric spur gear tooth
Mechanism and Machine Theory, 2015
Abstract To estimate the tooth form factor for a loaded symmetric spur gear tooth, some normalize... more Abstract To estimate the tooth form factor for a loaded symmetric spur gear tooth, some normalized standards like International Organization for Standardization (ISO) and American Gear Manufacturers Association (AGMA) are available. However, the tooth form factor for a loaded asymmetric spur gear tooth cannot be estimated through the available standards. An asymmetric spur gear tooth is one whose drive side pressure angle is different from the coast side pressure angle. In the present work, the standard ISO B methodology has been adapted suitably for estimating the tooth form factor and the stress correction factor in asymmetric spur gear tooth. Also, the critical root fillet parameters (critical root tooth thickness, bending moment arm and radius of curvature) and the tooth form factor for asymmetric spur gear tooth with several sets of drive side and coast side pressure angles are determined through an adapted ISO method and a comparative study with FEM is also carried out.
Load sharing based maximum fillet stress analysis of asymmetric helical gears designed through direct design — A parametric study
Abstract Direct gear design method is one of the most effective gear design approaches, which pro... more Abstract 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.
Determination of load dependent gear loss factor on asymmetric spur gear
Mechanism and Machine Theory
Abstract This paper shows the prediction of coefficient of friction and load dependent loss facto... more Abstract This paper shows the prediction of coefficient of friction and load dependent loss factor for spur gear drives with asymmetric tooth. An accurate evaluation of gear loss factor is important to exactly calculate the power loss and the corresponding mechanical efficiency of the asymmetric spur gear drive. In the present investigative research work, a formulation to accurately estimate the gear loss factor on asymmetric gear has been developed. The tooth load and the corresponding contact stress that develops at the symmetric and asymmetric gear contact surfaces are also evaluated through finite element method in order to deduce the friction coefficient and loss factor. The suitability of three distinct models is studied and compared in this paper. The asymmetric gear pair is analyzed and the loss factor is predicted for influence over the major drive parameters. It is revealed that the approach employed facilitate substantial enhancement in the efficiency which is confined by the detailed parametric study.
The surface tooth wear which occurs at the gear contact region due to inadequate contact strength... more The surface tooth wear which occurs at the gear contact region due to inadequate contact strength of the tooth is one of the predominant modes of gear failures. Currently, higher contact ratio spur gears are increasingly used in power transmission applications such as aircraft, wind turbine, automobiles and compact tracked vehicles due to their high load carrying capacity. In this work, the direct design is found to be one of the efficient gear design methods to reduce the tooth surface wear on high contact ratio asymmetric spur gears. Asymmetric gear tooth is defined, as one whose tooth geometry of the drive and coast sides is not symmetric. Asymmetry between tooth sides is achieved by providing two different pressure angles at the respective coast and drive side pitch circles. The area of existence diagrams for normal and high contact ratio gears have been developed to select suitable design solution with the given variables of gear ratio, contact ratio and teeth number. The conta...
Teeth Wear Enhancement Along the Tooth Profile of Spur Gear Drive by Balancing the Fillet Stress Through Positive Correction Factor
Advances in Simulation, Product Design and Development, 2019
This article suggests a modification in the correction factor which will improve the wear resista... more This article suggests a modification in the correction factor which will improve the wear resistance for the equalized fillet stress in spur gear drive. As ruled, higher transmission proportional drives have an altering stresses in the fillet of pinion and the wheel. This fillet stress can be equalized by utilizing addendum alteration system. This changed addendum can bring down the fillet stress in the pinion subsequently enhancing the load conveying limit of the drives. Here, the fillet stress is assessed utilizing finite element analysis (FEA) technique for various blends of S+ drives. This correction factor is given in the pinion; wheel with the end goal that the bending strength of the drive is improved. At last, the fillet stress is equalized by varying the correction factors for every one of these drives, and the upgraded estimation of balanced strength with enhanced wear resistance is recommended for the spur gear drive.
Journal of Solid Mechanics, 2020
The surface tooth wear which occurs at the gear contact region due to inadequate contact strength... more The surface tooth wear which occurs at the gear contact region due to inadequate contact strength of the tooth is one of the predominant modes of gear failures. Currently, higher contact ratio spur gears are increasingly used in power transmission applications such as aircraft, wind turbine, automobiles and compact tracked vehicles due to their high load carrying capacity. In this work, the direct design is found to be one of the efficient gear design methods to reduce the tooth surface wear on high contact ratio asymmetric spur gears. Asymmetric gear tooth is defined as one whose tooth geometry of the drive and coast sides is not symmetric. Asymmetry between tooth sides is achieved by providing two different pressure angles at the respective coast and drive side pitch circles. The area of existence diagrams for normal and high contact ratio gears have been developed to select suitable design solution with the given variables of gear ratio, contact ratio and teeth number. The conta...
Effect of Module on Wear Reduction in High Contact Ratio Spur Gears Drive Through Optimized Fillet Stress
The current study intends to predict the wear obstruction of high contact ratio spur gears over o... more The current study intends to predict the wear obstruction of high contact ratio spur gears over optimized fillet stress between the wheel and pinion. As the fillet region of the wheel is considered to be the critical region with high stress concentration, it becomes essential to study the wear depth at this enhanced bending strength. The optimization of fillet stress is carried out through profile modification technique and the tooth wear of the gear drive is examined using contact analysis and analytical method by taking in the tooth load distribution at the contact points, fillet stress and strength during contact for various work cycles. This examination additionally investigates the impact of module over depletion of material from the tooth surface of the transmission system and lastly the outcomes are conferred that the reduced stress for the high contact ratio gear drive has enhanced wear resistance.
Tooth root crack is considered as one of the crucial causes of failure in the gearing system and ... more Tooth root crack is considered as one of the crucial causes of failure in the gearing system and it occurs at the tooth root due to an excessive bending stress developed in the root region. The modern power transmission gear drives demand high bending load capacity, increased contact load capacity, low weight, reduced noise and longer life. These subsequent conditions are satisfied by the aid of precisely designed asymmetric tooth profile which turns out to be a suitable alternate for symmetric spur gears in applications like aerospace, automotive, gear pump and wind turbine industries. In all step up and step down gear drives (gear ratio > 1), the pinion (smaller in size) is treated as a vulnerable one than gear (larger in size) which is primarily due to the development of maximum root stress in the pinion tooth. This paper presents an idea to improve the bending load capacity of asymmetric spur gear drive system by achieving the same stresses between the asymmetric pinion and g...
Estimation of loss factor based on the load share model in improved bending strength spur gear drive system
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology
This paper demonstrates the prediction of loss factor for non-standard gear drives with equal str... more This paper demonstrates the prediction of loss factor for non-standard gear drives with equal stresses in the root region of the pinion and wheel. This implementation of equal stresses in the root region is achieved in the described model of a spur gear drive with higher transmission ratio using non-standard rack cutter. The aim is to discover the optimal modification point in the tooth profile by varying values of tooth thickness with at most balanced stresses in the gear pair considered for the study. A loss factor is predicted along the path of contact for a complete meshing cycle using finite element method. This paper studies and compares the distinct models and thereby identifies the suitable and appropriate models. The predicted loss factor includes the distribution of load sharing effect during the meshing which is excluded in the compared models. The gear pair is analyzed, and the loss factor is predicted for influence over the major drive parameters. It was observed that t...
Journal of Mechanical Engineering and Sciences
As lined, higher transmission ratio drives system will have uneven stresses in the root region of... more As lined, higher transmission ratio drives system will have uneven stresses in the root region of the pinion and wheel. To enrich this agility of uneven stresses in normal-contact ratio (NCR) gearing system, an enhanced system is desirable to be industrialized. To attain this objective, it is proposed to put on the idea of modifying the correction factor in such a manner that the bending strength of the gearing system is improved. In this work, the correction factor is modified in such a way that the stress in the root region is equalized between the pinion and wheel. This equalization of stresses is carried out by providing a correction factor in three circumstances: in pinion; wheel and both the pinion and the wheel. Henceforth performances of this S+, S0 and S- drives are evaluated in finite element analysis (FEA) and compared for balanced root stresses in parallel shaft spur gearing systems. It is seen that the outcomes gained from the modified drive have enhanced performance th...
IOP Conference Series: Materials Science and Engineering
Gear loss factor is one of the imperative parameter in estimating the power loss in a meshing gea... more Gear loss factor is one of the imperative parameter in estimating the power loss in a meshing gear pair. This paper demonstrates the prediction of gear loss factor parameter in spur gear drive using the load distribution technique. The aptness of two distinct contact ratios is studied and compared in this paper: Normal Contact Ratio (NCR) and High Contact Ratio (HCR). The described model is studied for gearing strength which is improved through profile modification technique. The ultimate focus is to enhance the gearing strength of the pinion in a spur gear drive by discovering the optimal modification point in the tooth profile with at most balanced stresses in the gear pair considered for the study. Using contact analysis, the stresses developed over the contracting surfaces are predicted through finite element method and it is balanced between the gear and pinion. A gear loss factor is predicted along the path of contact for a complete meshing cycle for this balanced drive. It is...
Influence of gear ratio on wear depth of nonstandard HCR spur gear drive with balanced fillet stress
Materials Today: Proceedings
Abstract In this paper, the wear depth of a nonstandard High Contact Ratio (HCR) spur gear drive ... more Abstract In this paper, the wear depth of a nonstandard High Contact Ratio (HCR) spur gear drive is investigated using contact analysis considering the load share between the tooth in contact, fillet stress and contact stress for number of mesh cycles in steel gears. The fillet stresses obtained using finite element method is balanced by varying the tooth thickness along the reference line. This method of changing the tooth thickness is referred as nonstandard HCR spur gear drive. Using this method, an improved nonstandard HCR spur gear drive is obtained in terms of bending strength. In this enhanced nonstandard HCR spur gear drive the wear depth is estimated analytically for balanced fillet stress. Also, this paper explores the influence of gear ratio over wear depth of nonstandard HCR spur gear drive and finally the results are discussed.
Performance enhancement of spur gear formed through asymmetric tooth
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology
Tooth fracture and surface wear are the major failure causes in a gearing system. With increasing... more Tooth fracture and surface wear are the major failure causes in a gearing system. With increasing demand for high power density gear applications, the need of effective gear design becomes an important requirement to improve gear life. This article presents a method to enhance the load carrying capacity in bending and contact, as well as wear resistance to increase gear efficiency through asymmetric tooth. Asymmetric gear is the one whose pressure angles at pitch circle on drive and coast sides are different. In the present investigation, the load shared by a teeth pair, fillet and contact stresses, wear resistance, frictional power losses and the respective mechanical efficiencies have been determined for comparative performance assessment of symmetric and asymmetric spur gears.
Evolution of balanced root stress and tribological properties in high contact ratio spur gear drive
Mechanism and Machine Theory
Abstract Tooth bending and surface wear are the two major causes of failure modes which occur due... more Abstract Tooth bending and surface wear are the two major causes of failure modes which occur due to inadequate bending and contact strength. In a gear drive, when the gear ratio is more than one the bending strength of the pinion and gear it is different. Consequently gear drive with an equivalent bending strength in the gear and pinion is called as a balanced gear drive. This can be attained by providing non-standard tooth thickness at the pitch circle in High Contact Ratio (HCR) spur gears. Non-standard HCR spur gear drive is one in which the tooth thickness at the pitch circle of the gear and pinion is not same. In the present study, tooth wear over the contacting surfaces for non-standard HCR spur gear drive is probed numerically through finite element analysis (FEA). In addition, the tooth load, contact stress, film thickness and sliding distance are also estimated for a balanced non-standard HCR spur gear drive. Also the effect of different gear parameters like pinion teeth number, pressure angle, addendum height and gear ratio on tooth wear along the line of action on non-standard HCR spur gear has been evaluated and discussed.
A mixed finite element and analytical method to predict load, mechanical power loss and improved efficiency in non-standard spur gear drives
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2017
A reasonably accurate estimation of gear power loss is desirable to maximize gear performance. Th... more A reasonably accurate estimation of gear power loss is desirable to maximize gear performance. The load share by teeth pair, contact stress, sliding speed, elastohydrodynamic film thickness and coefficient of friction are some of the most important contributing factors which determine frictional power losses in gears. This paper presents an improvement concept to minimize the load-related power losses (sliding and rolling power losses), which will lead to an enhancement in gear efficiency by selection of non-standard gears. The tooth thickness at the pitch circle of the pinion and gear is different in non-standard gears (kpπm > 0.5 πm and kgπm
Enhancement of Wear Resistance on Normal Contact Ratio Spur Gear Pairs through Non-Standard Gears
Wear, 2017
Abstract Tooth wear is considered to be one of the major causes of failure modes in gearing syste... more Abstract Tooth wear is considered to be one of the major causes of failure modes in gearing systems. The achieved service life of the geared unit mainly depends on the gear tooth strength and surface wear. Excessive wear is characterized by loss of tooth profile, which results in high noise and vibration, a minor loss of conjugate action and a reduction in efficiency. Hence, enhancement of gear life against wear becomes an important requirement for effective design detailing of gears. This article presents an idea to minimize the wear of the gear teeth by adopting non-standard gear. Non-standard gear is defined as one whose tooth thickness at the pitch circle is not equal to 0.5πm. In this study, the impact of the tooth thickness coefficient on tooth wear for standard and non-standard spur gears is numerically investigated. The non-standard tooth thickness in the pinion leads to enhancement of the tooth strength and leading to reduction of tooth wear. Finally, the influence of gear parameters such as gear ratio, pressure angle and pinion teeth number on wear depth, for non-standard pinion and gear has been investigated and the results of the parametric study are discussed.
Estimation of tooth form factor for normal contact ratio asymmetric spur gear tooth
Mechanism and Machine Theory, 2015
Abstract To estimate the tooth form factor for a loaded symmetric spur gear tooth, some normalize... more Abstract To estimate the tooth form factor for a loaded symmetric spur gear tooth, some normalized standards like International Organization for Standardization (ISO) and American Gear Manufacturers Association (AGMA) are available. However, the tooth form factor for a loaded asymmetric spur gear tooth cannot be estimated through the available standards. An asymmetric spur gear tooth is one whose drive side pressure angle is different from the coast side pressure angle. In the present work, the standard ISO B methodology has been adapted suitably for estimating the tooth form factor and the stress correction factor in asymmetric spur gear tooth. Also, the critical root fillet parameters (critical root tooth thickness, bending moment arm and radius of curvature) and the tooth form factor for asymmetric spur gear tooth with several sets of drive side and coast side pressure angles are determined through an adapted ISO method and a comparative study with FEM is also carried out.
Load sharing based maximum fillet stress analysis of asymmetric helical gears designed through direct design — A parametric study
Abstract Direct gear design method is one of the most effective gear design approaches, which pro... more Abstract 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.
Determination of load dependent gear loss factor on asymmetric spur gear
Mechanism and Machine Theory
Abstract This paper shows the prediction of coefficient of friction and load dependent loss facto... more Abstract This paper shows the prediction of coefficient of friction and load dependent loss factor for spur gear drives with asymmetric tooth. An accurate evaluation of gear loss factor is important to exactly calculate the power loss and the corresponding mechanical efficiency of the asymmetric spur gear drive. In the present investigative research work, a formulation to accurately estimate the gear loss factor on asymmetric gear has been developed. The tooth load and the corresponding contact stress that develops at the symmetric and asymmetric gear contact surfaces are also evaluated through finite element method in order to deduce the friction coefficient and loss factor. The suitability of three distinct models is studied and compared in this paper. The asymmetric gear pair is analyzed and the loss factor is predicted for influence over the major drive parameters. It is revealed that the approach employed facilitate substantial enhancement in the efficiency which is confined by the detailed parametric study.