Performance enhancement of spur gear formed through asymmetric tooth

2019 ◽  
Vol 233 (9) ◽  
pp. 1361-1378 ◽  
Author(s):  
R Prabhu Sekar
Keyword(s):  
Wear Resistance ◽  
Performance Enhancement ◽  
Spur Gear ◽  
Spur Gears ◽  
Comparative Performance ◽  
Gear Design ◽  
Load Carrying ◽  
Gear Efficiency ◽  
Increasing Demand ◽  
The One

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.

scholarly journals Research on the Design and Modification of Asymmetric Spur Gear

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaohe Deng ◽  
Lin Hua ◽  
Xinghui Han
Keyword(s):  
Computer Aided Design ◽  
Design Method ◽  
Geometric Model ◽  
Simulation Method ◽  
Transmission Error ◽  
Spur Gear ◽  
Geometric Shape ◽  
Spur Gears ◽  
Gear Design ◽  
Aided Design

A design method for the geometric shape and modification of asymmetric spur gear was proposed, in which the geometric shape and modification of the gear can be obtained directly according to the rack-cutter profile. In the geometric design process of the gear, a rack-cutter with different pressure angles and fillet radius in the driving side and coast side was selected, and the generated asymmetric spur gear profiles also had different pressure angles and fillets accordingly. In the modification design of the gear, the pressure angle modification of rack-cutter was conducted firstly and then the corresponding modified involute gear profile was obtained. The geometric model of spur gears was developed using computer-aided design, and the meshing process was analyzed using finite element simulation method. Furthermore, the transmission error and load sharing ratio of unmodified and modified asymmetric spur gears were investigated. Research results showed that the proposed gear design method was feasible and desired spur gear can be obtained through one time rapid machining by the method. Asymmetric spur gear with better transmission characteristic can be obtained via involute modification.

A Visual Basic Program to Calculate Gear Features

2001 ◽  
Author(s):  
Edward M. Vavrek
Keyword(s):  
Engineering Students ◽  
Selection Process ◽  
Visual Basic ◽  
Spur Gear ◽  
Basic Program ◽  
Design Analysis ◽  
Spur Gears ◽  
Analysis Program ◽  
Gear Design ◽  
Visual Basic Program

Abstract This paper describes a spur gear design analysis program written in visual basic. The program is used to assist engineering students in the design of spur gears, which involves many calculations and decisions. This software program simplifies and streamlines the design and selection process. Since the visual basic program is event driven, the user can go through the program by inputting values into text boxes and then initiating events by clicking on command buttons. An important feature of this program is the ability to insert pictures, tables, graphs, drawings, and figures to enhance the program functionality. Most inputs are taken from graphs, charts, or tables so the user knows where and how the information is obtained and used. Outputs are shown with their appropriate figures, drawings, or calculation formulas to assist the user in understanding how the output was derived. The software has the advantage of making minor changes to the problem quickly and easily to see how the output is affected.

scholarly journals Lubricant and Additive Effects on Spur Gear Fatigue Life

1986 ◽  
Vol 108 (3) ◽  
pp. 468-475 ◽  
Author(s):  
D. P. Townsend ◽  
E. V. Zaretsky ◽  
H. W. Scibbe
Keyword(s):  
Fatigue Life ◽  
Statistical Difference ◽  
Spur Gear ◽  
Antiwear Additives ◽  
Spur Gears ◽  
Additive Effects ◽  
Viscosity Coefficients ◽  
Surface Fatigue ◽  
Load Carrying ◽  
Endurance Tests

Spur gear endurance tests were conducted with six lubricants using a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The sixth lubricant was divided into four batches each of which had a different additive content. Lubricants tested with a phosphorous-type load carrying additive showed a statistically significant improvement in life over lubricants without this type additive. The presence of sulphur type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears. No statistical difference in life was produced with those lubricants of different base stocks but with similar viscosity, pressure-viscosity coefficients and antiwear additives. Gears tested with a 0.1 wt percent sulfur and 0.1 wt percent phosphorus EP additives in the lubricant had reactive films that were 200 to 400 Å (0.8 to 1.6 μin) thick.

Simplified Spur Gear Design

2016 ◽  
Author(s):  
Edward E. Osakue
Keyword(s):  
Contact Stress ◽  
Design Method ◽  
Spur Gear ◽  
Load Factor ◽  
Spur Gears ◽  
Bending Stress ◽  
Hertz Contact ◽  
Gear Design ◽  
Simplified Method ◽  
The Difference

A simplified design method (SDM) for spur gears is presented. The Hertz contact stress and Lewis root bending stress capacity models for spur gears have been reformulated and formatted into simplified forms. A scheme is suggested for estimating the AGMA J-factor in Lewis root bending stress for spur gears from a single curve for both pinion and gear instead of the conventional two curves. A service load factor is introduced in gear design that accounts for different conventional rated load modifier factors. It represents a magnification factor for the rated load in a gear design problem. Two design examples are considered for applications of the stress capacity models. In Example 1, the Hertz contact stress of the SDM deviates from AGMA value by 1.95%. The variance in Example 2 between the contact stress of the SDM and FEM is 1.184% while that between SDM and AGMA is 0.09%. The root bending stress of AGMA and SDM for the pinion in Example 1 differs by 1.44% and that for the gear by 6.59%. The difference between the root bending stress of AGMA and SDM for pinion and gear in Example 2 is 0.18%. These examples suggest that the new simplified method gives results that compare very favorably with both AGMA and FEM solutions. The simplified method developed is recommended mainly for preliminary design when quick but reliable solutions are sought.

scholarly journals An Analytical Method to Predict Efficiency of Aircraft Gearboxes

1986 ◽  
Vol 108 (3) ◽  
pp. 424-432 ◽  
Author(s):  
N. E. Anderson ◽  
S. H. Loewenthal ◽  
J. D. Black
Keyword(s):  
Friction Coefficient ◽  
Test Data ◽  
Analytical Method ◽  
Power Loss ◽  
Large Scale ◽  
Prediction Method ◽  
Computer Programs ◽  
Spur Gear ◽  
Spur Gears ◽  
Gear Efficiency

A spur gear efficiency prediction method previously developed by the authors was extended to include power loss of planetary gearsets. A friction coefficient model was developed for MIL-L-7808 oill based on disk machine data. This, combined with the recent capability of predicting losses in spur gears of nonstandard proportions, allows the calculation of power loss for complete aircraft gearboxes that utilize spur gears. The method was applied to the T56/501 turboprop gearbox and compared with measured test data. Bearing losses were calculated with large-scale computer programs. Breakdowns of the gearbox losses point out areas for possible improvement.

scholarly journals A Practical Approach to Gear Design and Lubrication: A Review

Lubricants ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 84
Author(s):  
Dario Croccolo ◽  
Massimiliano De Agostinis ◽  
Giorgio Olmi ◽  
Nicolò Vincenzi
Keyword(s):  
Weight Ratio ◽  
Point Of View ◽  
Spur Gears ◽  
Gear Design ◽  
Comprehensive Collection ◽  
Load Carrying ◽  
Definition Of ◽  
The Right ◽  
High Level ◽  
Continuous Demand

The modern design of mechanical parts, such as gears, goes through the continuous demand for a high level of efficiency and reliability, as well as an increased load carrying capacity and endurance life. The aim of the present paper was to perform a review and to collect practical examples in order to provide interesting tips and guidelines for gear design, including both its dimensioning and its lubrication. From this point of view, this paper is particularly novel, as it is a full-comprehensive collection of all the tools supporting gear design. Several practical aspects have been taken into account, including the definition of the right profile shifting, the selection of a proper lubricant, and the definition of the quality grade and of the tolerances needed to obtain the correct backlash. Finally, a numerical example is provided, addressing the research of the best solution to fit a given space, while maximizing the transmittable torque over weight ratio for two mating spur gears.

Dynamic Analysis of High-Contact-Ratio Spur Gears With Asymmetric Teeth

2008 ◽  
Author(s):  
F. Karpat ◽  
S. Ekwaro-Osire
Keyword(s):  
Numerical Technique ◽  
Spur Gear ◽  
Dynamic Loads ◽  
Spur Gears ◽  
Load Carrying Capacity ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Gear Teeth ◽  
Load Carrying ◽  
Gear Contact

In this research, a numerical technique is used to study the performance of high-contact-ratio (HCR) spur gears with asymmetric teeth. Asymmetric teeth have been shown to minimize dynamic loads and to increase the load carrying capacity. This is due to the fact that these teeth have a larger pressure angle on the drive side compared to the coast side. In literature, symmetric gear teeth with HCR have been shown to also yield low dynamic loads and high load capacities. HCR gears have these positive attributes because for gears in a mesh, the number of tooth pairs sharing the transmitted load alternates between two and three. In this study, the separate benefits of an HCR gear and asymmetric teeth are unified into a spur gear with asymmetric teeth. In this case, the effect of the gear contact ratio, addendum factor, mesh stiffness, pressure angles, and operation speeds on dynamic tooth loads are considered. The influences of these parameters on dynamic response are presented and discussed. A comparison between standard and non standard gear pairs in literature is also presented, with respect to dynamic tooth loads. Sample simulation results, which were obtained by using an in-house computer program, are discussed. The results obtained are shown to match well with some related analytical and experimental results in literature. It is further demonstrated that HCR spur gears with asymmetric teeth do provide a marked advantage compared to the conventional spur gears with symmetric teeth.

A mixed finite element and analytical method to predict load, mechanical power loss and improved efficiency in non-standard spur gear drives

2017 ◽  
Vol 231 (11) ◽  
pp. 1408-1424 ◽  
Author(s):  
R Prabhu Sekar ◽  
V Edwin Geo ◽  
Leenus Jesu Martin
Keyword(s):  
Power Loss ◽  
Mixed Finite Element ◽  
Mechanical Efficiency ◽  
Spur Gear ◽  
Gear Ratio ◽  
Accurate Estimation ◽  
Power Losses ◽  
Contributing Factors ◽  
Comparative Performance ◽  
Gear Efficiency

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 < 0.5 πm), whereas it is equal in standard gears (kpπm = kgπm = 0.5 πm). In this work, the load share-based frictional power loss and the respective mechanical efficiency have been determined for comparative performance of standard and non-standard gears. Finally, the influence of various gear and drive parameters such as gear ratio, pressure angle pinion teeth number and addendum height factor on gear efficiency has also been investigated and the results of the parametric study are discussed.

Effect of design parameters on stresses occurring at the tooth root in a spur gear pressed on a shaft

2021 ◽  
pp. 095440892199529
Author(s):  
Fatih Güven
Keyword(s):  
Internal Pressure ◽  
Tangential Stress ◽  
Spur Gear ◽  
Design Parameters ◽  
Interference Fit ◽  
Gear Design ◽  
Compact Design ◽  
Fit Tolerance ◽  
Moderate Stress ◽  
Good Agreement

Gears are commonly used in transmission systems to adjust velocity and torque. An integral gear or an interference fit could be used in a gearbox. Integral gears are mostly preferred as driving gear for a compact design to reduce the weight of the system. Interference fit makes the replacement of damaged gear possible and re-use of the shaft compared to the integral shaft. However, internal pressure occurs between mating surfaces of the components mated. This internal pressure affects the stress distribution at the root and bottom land of the gear. In this case, gear parameters should be re-considered to assure gear life while reducing the size of the gear. In this study, interference fitted gear-shaft assembly was examined numerically. The effects of rim thickness, profile shifting, module and fit tolerance on bending stress occurring at the root of the gear were investigated to optimize gear design parameters. Finite element models were in good agreement with analytical solutions. Results showed that the rim thickness of the gear is the main parameter in terms of tangential stress occurring at the bottom land of the gear. Positive profile shifting reduces the tangential stress while the pitch diameter of the gear remains constant. Also, lower tolerance class could be selected to moderate stress for small rim thickness.

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