scholarly journals A Life Study of AISI M-50 and Super Nitralloy Spur Gears With and Without Tip Relief

1974 ◽  
Vol 96 (4) ◽  
pp. 583-589 ◽  
Author(s):  
D. P. Townsend ◽  
E. V. Zaretsky
Keyword(s):  
Gear Tooth ◽  
Spur Gear ◽  
Consumable Electrode ◽  
Spur Gears ◽  
Life Study ◽  
Tooth Fracture ◽  
The Difference

Tests were conducted at 350 K (170 deg F) with groups of 8.9 cm (3.5-in.)-pitch-diameter spur gear with and without tip relief made of consumable-electrode vacuum melted (CVM) Super Nitralloy (5Ni-2Al) and CVM AISI M-50 steel. The AISI M-50 gears without tip relief had lives approximately 50 percent longer than the Super Nitralloy gears without tip relief. However, the Super Nitralloy gears with tip relief had lives equal to the AISI M-50 gears without tip relief. The difference in lives were not statistically significant. All gears failed by classical pitting fatigue at the pitch circle. However, the AISI M-50 gears with tip relief failed by tooth fracture. AISI M-50 gear sets without tip relief having a spalled gear tooth which were deliberately overrun after spalling had occurred, failed by tooth fracture.

scholarly journals A Life Study of Ausforged, Standard Forged, and Standard Machined AISI M-50 Spur Gears

1976 ◽  
Vol 98 (3) ◽  
pp. 418-425 ◽  
Author(s):  
D. P. Townsend ◽  
E. N. Bamberger ◽  
E. V. Zaretsky
Keyword(s):  
Fatigue Life ◽  
Gear Tooth ◽  
Vacuum Arc ◽  
Spur Gears ◽  
Bending Fatigue ◽  
Life Study ◽  
Tooth Fracture ◽  
The Difference

Tests were conducted at 350 K (170° F) with three groups of 8.9 cm (3.5 in.) pitch diameter spur gears made of vacuum-induction melted (VIM), vacuum-arc remelted (VAR), AISI M-50 steel and one group of vacuum-arc remelted (VAR) AISI 9310 steel. The pitting fatigue life of the standard forged and ausforged gears was approximately five times that of the VAR AISI 9310 gears and ten times that of the bending fatigue life of the standard machined VIM-VAR AISI M-50 gears run under identical conditions. There was a slight decrease in the 10-percent life of the ausforged gears from that for the standard forged gears. However, the difference is not statistically significant. The standard machined gears failed primarily by gear tooth fracture while the forged and ausforged VIM-VAR AISI M-50 and the VAR AISI 9310 gears failed primarily by surface pitting fatigue. The ausforged gears had a slightly greater tendency to fail by tooth fracture than the standard forged gears.

scholarly journals A Method of Selecting Grid Size to Account for Hertz Deformation in Finite Element Analysis of Spur Gears

1982 ◽  
Vol 104 (4) ◽  
pp. 759-764 ◽  
Author(s):  
J. J. Coy ◽  
C. Hu-Chih Chao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Gear Tooth ◽  
Spur Gear ◽  
Grid Size ◽  
Spur Gears ◽  
Element Analysis ◽  
Element Size ◽  
Full Effect ◽  
The Finite Element Analysis

A method of selecting grid size for the finite element analysis of gear tooth deflection is presented. The method is based on a finite element study of two cylinders in line contact, where the criterion for establishing element size was that there be agreement with the classic Hertzian solution for deflection. Many previous finite element studies of gear tooth deflection have not included the full effect of the Hertzian deflection. The present results are applied to calculate deflection for the gear specimen used in the NASA spur gear test rig. Comparisons are made between the present results and the results of two other methods of calculation. The results have application in design of gear tooth profile modifications to reduce noise and dynamic loads.

Explicit Parametric Method for Optimal Spur Gear Tooth Profile Definition

2013 ◽  
Vol 633 ◽  
pp. 87-102 ◽  
Author(s):  
Ivana Atanasovska ◽  
Radivoje Mitrovic ◽  
Dejan Momcilovic
Keyword(s):  
Gear Tooth ◽  
Load Capacity ◽  
Parametric Method ◽  
Spur Gear ◽  
Tooth Profile ◽  
Spur Gears ◽  
Element Analysis ◽  
Engineering Research ◽  
Profile Optimization ◽  
Current Engineering

The gear tooth profile has an immense effect on the main operating parameters of gear pairs (load capacity, working life, efficiency, vibrations, etc). In current engineering research and practice, there is a strong need to develop methods for tooth profile optimization. In this paper a new method for selecting the optimal tooth profile parameters of spur gears is described. This method has been named the Explicit Parametric Method (EPM). The addendum modification coefficient, radius of root curvature, and pressure angle of the basic rack for cylindrical gears, have been identified as the main tooth profile parameters of spur gears. Therefore, the EPM selects the optimal values for these three tooth profile parameters. Special attention has been paid to develop a method of adjustment for the particular working conditions and explicit optimization requirements. The EPM for optimal tooth profile parameters of gears uses contact nonlinear Finite Element Analysis (FEA) for calculation of deformations and stresses of gear pairs, in addition to explicit comparative diagrams for optimal tooth profile parameter selection.

scholarly journals Study of Lubricant Jet Flow Phenomena in Spur Gears

1975 ◽  
Vol 97 (2) ◽  
pp. 283-288 ◽  
Author(s):  
L. S. Akin ◽  
J. J. Mross ◽  
D. P. Townsend
Keyword(s):  
Motion Picture ◽  
High Speed ◽  
Drop Size ◽  
Gear Tooth ◽  
Jet Flow ◽  
Spur Gear ◽  
Spur Gears ◽  
Gear Teeth ◽  
Flow Phenomena ◽  
Oil Jet

Lubricant jet flow impingement and penetration depth into a gear tooth space were measured at 4920 and 2560 using a 8.89-cm- (3.5-in.) pitch dia 8 pitch spur gear at oil pressures from 7 × 104 to 41 × 104 N/m2 (10 psi to 60 psi). A high speed motion picture camera was used with xenon and high speed stroboscopic lights to slow down and stop the motion of the oil jet so that the impingement depth could be determined. An analytical model was developed for the vectorial impingement depth and for the impingement depth with tooth space windage effects included. The windage effects on the oil jet were small for oil drop size greater than 0.0076 cm (0.003 in.). The analytical impingement depth compared favorably with experimental results above an oil jet pressure of 7 × 104 N/m2 (10 psi). Some of this oil jet penetrates further into the tooth space after impingement. Much of this post impingement oil is thrown out of the tooth space without further contacting the gear teeth.

Determining the Lewis Factor for Plastic Spur Gears With Asymmetric Teeth

2009 ◽  
Author(s):  
J. L. Moya ◽  
A. S. Machado ◽  
A. M. Becerra ◽  
J. A. Vela´zquez ◽  
R. Goytisolo
Keyword(s):  
Theoretical Analysis ◽  
Direct Effect ◽  
Spur Gear ◽  
Spur Gears ◽  
Gear Teeth ◽  
Tooth Fracture ◽  
Tooth Width

The basic weakness of plastic spur gear teeth is tooth fracture brought on by the accumulation of stress at the root of the tooth and by the geometry of the tooth. Tooth width and height play a major role in failure, as does the Lewis factor, which has a direct effect on the expression to calculate tooth strength. This study describes a theoretical analysis of a procedure to determine the Lewis factor for asymmetric teeth.

Prediction of stress in fillet portion of spur gears using artificial neural networks

2007 ◽  
Vol 22 (1) ◽  
pp. 41-51
Author(s):  
M.S. Shunmugam ◽  
N. Siva Prasad
Keyword(s):  
Neural Network ◽  
Gear Tooth ◽  
Spur Gear ◽  
Activation Function ◽  
Training Data ◽  
Spur Gears ◽  
Pressure Angle ◽  
The Neural Network ◽  
Artificial Neural ◽  
Taguchi’S Design Of Experiments

AbstractA fillet curve is provided at the root of the spur gear tooth, as stresses are high in this portion. The fillet curve may be a trochoid or an arc of suitable size as specified by designer. The fillet stress is influenced by the fillet geometry as well as the number of teeth, modules, and the pressure angle of the gear. Because the relationship is nonlinear and complex, an artificial neural network and a backpropagation algorithm are used in the present work to predict the fillet stresses. Training data are obtained from finite element simulations that are greatly reduced using Taguchi's design of experiments. Each simulation takes around 30 min. The 4-5-1 network and a sigmoid activation function are chosen. TRAINLM function is used for training the network with a learning rate parameter of 0.01 and a momentum constant of 0.8. The neural network is able to predict the fillet stresses in 0.03 s with reasonable accuracy for spur gears having 25–125 teeth, a 1–5 mm module, a 0.05–0.45 mm fillet radius, and a 15°–25° pressure angle.

Mixed Lubricated Line Contact Analysis for Spur Gears using a Deterministic Model

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Huaiju Liu ◽  
Ken Mao ◽  
Caichao Zhu ◽  
Xiangyang Xu
Keyword(s):  
Deterministic Model ◽  
Gear Tooth ◽  
Spur Gear ◽  
Tooth Surface ◽  
Spur Gears ◽  
Line Contact ◽  
Unified Approach ◽  
Asperity Contacts ◽  
Newtonian Behavior ◽  
Pressure Ripples

The unified approach based upon the Reduced Reynolds technique is applied to develop a deterministic transient mixed lubrication line contact model. This model is used in spur gear applications to comprehensively show effects of roughness, working conditions, i.e., rotational speeds and loads on pressure ripples and severity of asperity contacts. Results show effects of the speed, the load, as well as the RMS value are coupled which makes it difficult to evaluate lubrication states by only considering one variable. Considering the Ree-Eyring non-Newtonian behavior could alleviate pressure ripples significantly, compared with the Newtonian fluid assumption. Small RMS values of surfaces, which could be achieved by superfinish techniques, would be desirable when evaluating gear tooth surface contact performances.

Investigation on Structural Steel and Silicon Carbide Aluminum Metal Matrix Composite Spur Gears Using PTC Creo and ANSYS 16.0

2018 ◽  
Vol 937 ◽  
pp. 33-41
Author(s):  
S. Nallusamy ◽  
M. Rajaram Narayanan ◽  
S. Saravanan
Keyword(s):  
Composite Materials ◽  
Structural Steel ◽  
Power Transmission ◽  
Gear Tooth ◽  
Minimum Weight ◽  
Spur Gear ◽  
Spur Gears ◽  
Assembly Model ◽  
Aluminum Metal Matrix Composite ◽  
Engineering And Technology

In the field of Engineering and Technology, Gear is one of the most significant and essential component in mechanical power transmission system. General devices have major applications in various fields like automotives, industrial rotational machines, lifting devices, etc. Gears are usually subjected to fluctuating loads while in action. Gear tooth mainly fails due to excessive bending stress and excessive contact stress. Thus while designing the gear it is very necessary and vital to analyze the stresses induced in the gear for its safe operation. Weight reduction of gear is also one of the main design criteria as it has a great role in improving the efficiency of the entire system. Nowadays engineering components made up of composite materials and plastics find increasing applications. The components made by the composite materials provide reasonable mechanical properties with minimum weight. The objective of this research is to develop the spur gear and pinion assembly model using engineering simulation PTC Creo and imported to 3-D design software ANSYS workbench 16.0 for working on the static structural analysis. The analysis was carried out by considering different materials for gears like structural steel, polycarbonate and 20%AlSiC. From the observed results it was found that, 20%AlSiC composite material has mass reduction of about 45%, hence it is suitable for light weight applications.

Further Evaluation of Spur Gear Tooth Profile Designs Used in Heavily Loaded Transmissions

2011 ◽  
Author(s):  
Nihat Yıldırım ◽  
Hakan I˙s¸c¸i ◽  
Abdullah Akpolat
Keyword(s):  
Gear Tooth ◽  
Transmission Error ◽  
Spur Gear ◽  
Tooth Profile ◽  
Design Parameters ◽  
Preference Order ◽  
Spur Gears ◽  
Tooth Root ◽  
Contact Ratio ◽  
Practical Applications

Aerospace applications require special procedures for component design and manufacturing. Spur gears of different designs, because of their simpler geometries, are used in vital units-transmissions of helicopters and alike aerospace vehicles. In this study, performances of various profile designs of previously researched low and high contact ratio spur gears with some realistic design parameters are studied. Effects of the realistic parameters of variable tooth pair stiffness, relief shape, and adjacent pitch error on Transmission Error (TE), tooth loads and root stresses are presented; composition of these parameters determines the efficiency of the gearbox assembly. Detail of minimization of tooth root stress through optimized/proper design of relief is described. More comprehensive comparison of the gear tooth profile design cases is done to be able to guide aerospace transmission designers for practical applications with realistic parameters for each of the design cases. A preference order is done among the design cases, depending on effect of some design parameters on the results such as tooth loads, tooth root stresses, TE curves and peak-to-peak TE values.

A New Photoelastic Investigation of the Dynamic Bending Stress of Spur Gears

2003 ◽  
Vol 125 (2) ◽  
pp. 365-372 ◽  
Author(s):  
Ming-Jong Wang
Keyword(s):  
Critical Points ◽  
Gear Tooth ◽  
Spur Gear ◽  
Behavioral Characteristics ◽  
Spur Gears ◽  
Bending Stress ◽  
Dynamic Effects ◽  
Contact Points ◽  
Photoelastic Investigation ◽  
Bending Stresses

In this paper, the maximum tensile bending stress (MTBS) and the critical point in the root fillet of spur gear tooth during transmission are determined by a digital photoelastic system involving real time imaging. The behavioral characteristics of the bending stresses of the gear tooth are analyzed at different rotation speeds, transmitted torques, and contact points. Then, the dynamic effects, the various critical points and the maximum tensile bending stresses are compared experimentally and theoretically, and discussed. Finally, the best approaches for determining the maximum bending stress and its position in the root fillet of spur gear tooth are recommended.

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