Computer Aided Analysis of Bending Strength of Involute Spur Gears with Asymmetric Profile

2004 ◽  
Vol 127 (3) ◽  
pp. 477-484 ◽  
Author(s):  
Kadir Cavdar ◽  
Fatih Karpat ◽  
Fatih C. Babalik
Keyword(s):  
Computer Program ◽  
Bending Strength ◽  
Spur Gears ◽  
Bending Stress ◽  
Contact Ratio ◽  
Computer Aided Analysis ◽  
Tooth Form ◽  
Stress Concentration Factors ◽  
Stress Minimization

This paper presents a method for the determination of bending stress minimization of involute spur gears. A computer program has been developed to investigate the variation of bending stress and contact ratio depending on the pressure angle on the drive side. Since asymmetric tooth is not standard, the tooth model, which was introduced by DIN 3990/Method C and ISO/TC 60, has been adjusted for asymmetric tooth by the authors. The determination of the tooth form and stress concentration factors for asymmetric tooth has been accomplished for each different parameter (pressure angles, tool radius, rack shift, etc.). The sample results, which were obtained by using a developed computer program, are illustrated with numerical examples.

The Changing Law of Tooth Bending Stress for Herringbone Gears with High Contact Ratio

2010 ◽  
Vol 139-141 ◽  
pp. 965-969 ◽  
Author(s):  
Le Hao Chang ◽  
Geng Liu
Keyword(s):  
Maximum Stress ◽  
Bending Strength ◽  
Maximum Load ◽  
Spur Gears ◽  
Bending Stress ◽  
Contact Ratio ◽  
Load Distributions ◽  
Generating Method ◽  
Definition Of ◽  
Herringbone Gear

From the principle of generating method, the precise model of an involute herringbone gear was built. The accurate load distributions of herringbone gear were obtained in different meshing positions in linear programming method. Then the changing course of root bending stress along with the variation of meshing position was gained. The calculation process realized the automatic definition of loads and boundary conditions, and found out the value and the position when the tooth root has maximum bending stress. The results showed that the maximum stress usually appears near the position when the tooth bears maximum load. Be different from spur gears, the maximum stress of herringbone gears will possibly appear in the section where more teeth couples are engaged. The analysis can effectively provide reference for checking tooth bending strength of herringbone gears.

The Design, Generation, and Simulation of Meshing of Worm-Gear Drive With Longitudinally Localized Contacts

2000 ◽  
Vol 122 (2) ◽  
pp. 201-206 ◽  
Author(s):  
I. H. Seol
Keyword(s):  
Computer Program ◽  
Longitudinal Direction ◽  
Worm Gear ◽  
Contact Ratio ◽  
Transmission Errors ◽  
Gear Drive ◽  
Bearing Contact ◽  
Design Generation ◽  
Gear Drives

The design and simulation of meshing of a single enveloping worm-gear drive with a localized bearing contact is considered. The bearing contact has a longitudinal direction and two branches of contact path. The purpose of localization is to reduce the sensitivity of the worm-gear drive to misalignment. The author’s approach for localization of bearing contact is based on the proper mismatch of the surfaces of the hob and drive worm. The developed computer program allows the investigation of the influence of misalignment on the shift of the bearing contact and the determination of the transmission errors and the contact ratio. The developed approach has been applied for K type of single-enveloping worm-gear drives and the developed theory is illustrated with a numerical example. [S1050-0472(00)00502-X]

Determination of Addendum Modification Coefficients for Spur Gears Operating at Non-Standard Center Distances

2003 ◽  
Author(s):  
M. A. Sahir Arikan
Keyword(s):  
Gear Tooth ◽  
Gear Ratio ◽  
Spur Gears ◽  
Contact Ratio ◽  
Performance Variables ◽  
Practical Design ◽  
Gear Drives ◽  
Maximum Contact ◽  
Center Distance

Although it is possible to find some recommended conventional values both for the sum of the addendum modification coefficients and for the allocation of the sum of the addendum modification coefficients (e.g. ISO/TR 4467), a detailed analysis is necessary to determine the addendum modification coefficient values for the desired optimization criteria and the performance since the main objective of the above mentioned sources is to facilitate practical design of non-standard gear drives which will not have problems while operating. They give practical average values within a safe range. In this study, by considering the required gear ratio, center distance and the desired backlash, alternative gear pairs are determined and corresponding gear performance variables are calculated in order to allocate the addendum modification coefficients for the pinion and the gear by using criteria such as: not having undercut or pointed (or excessively-thinned-tip) tooth, having desired proportions for the lengths of the dedendum and addendum portions of the line of action, having maximum contact ratio, having sufficient bottom clearance, having minimum contact stresses, having balanced pinion and gear tooth root stresses, having equal pinion and gear lives, etc.

A Method for Determining the AGMA Tooth Form Factor from Equations for the Generated Tooth Root Fillet

1986 ◽  
Vol 108 (2) ◽  
pp. 270-279 ◽  
Author(s):  
M. A. Lopez ◽  
R. T. Wheway
Keyword(s):  
Form Factor ◽  
Iterative Procedure ◽  
Gear Tooth ◽  
Critical Section ◽  
Tooth Root ◽  
Bending Stress ◽  
Tooth Form ◽  
Computer Generation ◽  
Tooth Section

The determination of the AGMA tooth form factor requires that the dimensions of the critical tooth section, at which the maximum bending stress is deemed to occur, be found. Critical section dimensions have traditionally been measured from a scaled generated layout of the tooth profile. The layout procedure, however, requires very careful drafting, and even then it is difficult to achieve really satisfactory accuracy because of the complex operations required to produce the fillet curve, with the added difficulty of estimating the point of tangency with the Lewis iso-bending stress parabola. Although a number of analytical methods are available for computing the critical section dimensions, their solution has generally been cumbersome, or convergence on the correct solution remained a problem. This paper presents equations for the gear tooth root fillet curve which have been derived from an analysis of the relative motion between a rack cutter and gear tooth during the generating cycle. An improved iterative procedure is used to find the critical tooth section dimensions from these equations. A further application of the root fillet equations, which is also covered, is in the computer generation of tooth profiles for assessment of the final tooth shape.

Paper 5: Design Aspects of Large Marine Engines

1966 ◽  
Vol 181 (8) ◽  
pp. 10-19
Author(s):  
J. F. Butler ◽  
F. Ørbeck
Keyword(s):  
Thermal Loading ◽  
Bending Moments ◽  
Bending Stress ◽  
Slow Speed ◽  
Piston Head ◽  
Marine Engines ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Frame Stiffness

The paper deals with large slow-speed marine engines with a section on crankshaft stresses, including dynamic torque calculation; static bending moments owing to firing pressure, inertia, and misalignment; combined torque and bending stress; and experimental determination of stress concentration factors in the fillet radii. Other sections deal with top end bearing loading including cyclic variation, piston head stresses, deflection of bearing housings, prestressing of main bolts, frame stiffness, and stress in combustion chamber studs as a result of pressure and thermal loading.

scholarly journals Real contact ratio and tooth bending stress calculation for plastic/plastic and plastic/steel spur gears

2021 ◽  
Vol 22 ◽  
pp. 30
Author(s):  
Toni Jabbour ◽  
Ghazi Asmar ◽  
Mohamad Abdulwahab ◽  
Jose Nasr
Keyword(s):  
Spur Gears ◽  
Bending Stress ◽  
Contact Ratio ◽  
Stress Variation ◽  
Real Contact ◽  
Number Of Teeth ◽  
Effective Contact ◽  
Critical Configurations ◽  
Plastic Gears ◽  
Plastic Steel

This paper presents an iterative method for calculating the effective contact ratio and the bending tooth stress for a pair of plastic/plastic and plastic/steel spur gears with an involute profile. In this method, the pinion and the gear are modeled, at each moment of the mesh cycle, as equivalent springs in parallel undergoing the same displacement along the line of action. This leads to the calculation of the bending stress by taking into account the number of teeth initially in contact and those which enter in contact prematurely. We also investigate the influence of certain gear parameters, such as, the number of teeth, the pressure angle, and the module on the behavior of a pair of meshed gears. In addition, the variation of the bending stress at the tooth fillet is investigated for a pair of plastic/plastic and a pair of plastic/steel spur gears, in order to determine the critical configurations for which the bending stress is maximum. In general, the results obtained from the present method also show that the stress variation in plastic/plastic gears differs markedly from that in plastic/steel gears.

Compact Design of High-Contact-Ratio Spur Gears

2020 ◽  
Author(s):  
Tuan H. Nguyen
Keyword(s):  
Spur Gear ◽  
Operating Parameters ◽  
Spur Gears ◽  
Bending Stress ◽  
Contact Ratio ◽  
Dynamic Design ◽  
Compact Design ◽  
Profile Errors ◽  
Tooth Profile Errors ◽  
Root Stress

Abstract This study presents a computer simulation for the dynamic design of compact high-contact-ratio spur gear transmissions. High contact ratio gears have the potential to produce lower dynamic tooth loads and minimum root stress but they can be sensitive to tooth profile errors. The analysis presented in this work was performed by using the NASA gear dynamics code DANST (Dynamic Analysis of Spur Gear Transmissions). In the analysis, the addendum ratio (addendum/diametral pitch) was varied over the range 1.30 to 1.40 to obtain a contact ratio of 2.00 or higher. The constraints of bending stress limit and involute interference provide the main criteria for this investigation. Compact design of high-contact-ratio gears with different gear ratios and pressure angles was investigated. Comparison of compact design between low-contact-ratio and high-contact-ratio gears was conducted. With the same operating parameters, high-contact-ratio gears appear to have much more compact design than low-contact-ratio gears. For compact design of high-contact-ratio gears, a diametral pitch of 6.00 appears to be the best choice for an optimal gear set.

Search method applied for gear tooth bending stress prediction in normal contact ratio asymmetric spur gears

2018 ◽  
Vol 232 (24) ◽  
pp. 4647-4663 ◽  
Author(s):  
Benny Thomas ◽  
K Sankaranarayanasamy ◽  
S Ramachandra ◽  
SP Suresh Kumar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Gear Tooth ◽  
Search Method ◽  
International Organization ◽  
Spur Gears ◽  
Bending Stress ◽  
Contact Ratio ◽  
Element Analysis ◽  
Normal Contact

Various analytical methods have been developed by designers to predict gear tooth bending stress in asymmetric spur gears with an intention to improve the accuracy of predicted results and to reduce the need for time consuming finite element analysis at the early stages of gear design. Asymmetry in the drive and coast side of asymmetric spur gears poses difficulty in direct application of well-known procedures like American Gear Manufacturers Association and International Organization for Standardization in the prediction of gear tooth bending stress. In earlier works, ISO-6336-3 methodology was suitably modified and adapted to predict asymmetric spur gear tooth bending stress. This approach is based on certain assumptions on the location of critical section which could introduce error in the predicted maximum bending stress. The present work is to analytically predict gear tooth bending stress in normal contact ratio asymmetric spur gears based on a more rigorous analytical approach. This includes a fundamental study on the gear tooth orientation used to define the coordinate system, determination of maximum bending stress by search along the fillet profile and to obtain stress profile along the fillet. Gear tooth bending stress obtained from the present work using Search method is compared against the results obtained from earlier adapted International Organization for Standardization method and Finite Element Analysis. This study recommends a new coordinate system and method for analytical prediction of gear tooth bending stress in normal contact ratio asymmetric spur gears.

Effect of Drive Side Contact Ratio on Direct Design Asymmetric High Contact Ratio Spur Gear Based on Load Sharing

2014 ◽  
Vol 592-594 ◽  
pp. 2292-2296 ◽  
Author(s):  
P. Marimuthu ◽  
G. Muthuveerappan
Keyword(s):  
Parametric Design ◽  
Load Sharing ◽  
Spur Gear ◽  
Spur Gears ◽  
Bending Stress ◽  
Contact Ratio ◽  
Normal Contact ◽  
Critical Loading ◽  
Direct Design ◽  
Single Tooth

The aim of this paper is to determine the effect on direct design asymmetric high contact ratio spur gear based on tooth load sharing. A unique Ansys parametric design language code is developed for this study. The load sharing based bending and contact stresses are determined for different drive side contact ratios. In addition to that the location of critical loading point is determined. Because the critical loading point for high contact ratio spur gear not lies on fixed point like normal contact ratio spur gears namely highest point of single tooth contact. In conclusion an increase in drive side contact ratio leads to increase in the load sharing based bending stress and decrease in the contact stress at the critical loading point.

The Synthesis of Tooth Profile Shapes and Spur Gears of High Load Capacity

1970 ◽  
Vol 92 (3) ◽  
pp. 543-551 ◽  
Author(s):  
A. O. Lebeck ◽  
E. I. Radzimovsky
Keyword(s):  
Bending Strength ◽  
Load Capacity ◽  
High Capacity ◽  
High Hardness ◽  
Spur Gear ◽  
Speed Ratio ◽  
Spur Gears ◽  
Gear Pair ◽  
Contact Ratio ◽  
High Load Capacity

In this work a method is presented for the synthesis of high capacity noninvolute spur gears and tooth profiles. Two gear capacity criteria are used in the synthesis: (1) the capacity based on maximum allowable Hertz stress and (2) the capacity based on the bending strength of the tooth. These capacity criteria are related to a generalized noninvolute gear geometry which includes the factors number of teeth and contact ratio. It was found that there are certain optimal relationships which exist among the noninvolute parameters which lead to a solution, for a maximum capacity noninvolute gear pair. For a speed ratio of one to five it was found that a significant capacity advantage exists for the synthesized noninvolute gear pair (compared to a 20-deg involute spur gear pair) for moderate as well as high hardness values. For a speed ratio of one to one a capacity advantage was found for moderate hardness but the advantage decreased significantly for high hardness.

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