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.

scholarly journals Optimization of Tooth Root Profile Using Bezier Curve with G2 Continuity to Reduce Bending Stress of Asymmetric Spur Gear Tooth

2018 ◽  
Vol 237 ◽  
pp. 03010 ◽  
Author(s):  
Priyakant Vaghela ◽  
Jagdish Prajapati
Keyword(s):  
Stress Concentration ◽  
Gear Tooth ◽  
Spur Gear ◽  
Bézier Curve ◽  
Bezier Curve ◽  
Tooth Root ◽  
Geometric Continuity ◽  
Bending Stress ◽  
Gear Design ◽  
G2 Continuity

This research describes simple and innovative approach to reduce bending stress at tooth root of asymmetric spur gear tooth which is desire for improve high load carrying capacity. In gear design at root of tooth circular-filleted is widely used. Blending of the involute profile of tooth and circular fillet creates discontinuity at root of tooth causes stress concentration occurs. In order to minimize stress concentration, geometric continuity of order 2 at the blending of gear tooth plays very important role. Bezier curve is used with geometric continuity of order 2 at tooth root of asymmetric spur gear to reduce bending stress.

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.

Deformation and Bending Stress Analysis of a Three-dimensional, Thin-rimmed Gear

2001 ◽  
Vol 124 (1) ◽  
pp. 129-135 ◽  
Author(s):  
Shuting Li
Keyword(s):  
Critical Stress ◽  
Gear Tooth ◽  
Three Dimensional ◽  
Deformation Model ◽  
Tooth Root ◽  
Bending Stress ◽  
The Finite Element Method ◽  
Stress Point ◽  
Bending Stresses ◽  
The Web

This paper analyzed the deformations and bending stresses of a three-dimensional (3D), thin-rimmed gear (TRG) through using the finite element method (FEM) and a whole gear deformation model. The gear’s deformations and stresses at every part are analyzed in detail. In contrast with tooth bending deformations of a solid gear, 3D-TRG has not only tooth bending deformations, but also rim and web bending deformations. This paper found that the thin rim and web share about 70% deformations in the total deformations of the 3D-TRG and the gear tooth share only about 30%. It is also pointed out by this paper that not only the root stresses of the 3D-TRG are much greater than the solid gear because of the rim and web deformations, but also there are much greater stresses existing in the joint of the thin rim and the web. Especially, when the rim thickness becomes very thin, stresses at the joint shall become much greater than the root stresses. It is very necessary to regard the joint as the second critical stress point as well as the tooth root when to design 3D-TRG.

An Approach to the Determination of Spur Gear Tooth Root Fillet

2004 ◽  
Vol 126 (2) ◽  
pp. 336-340 ◽  
Author(s):  
V. B. Math ◽  
Satish Chand
Keyword(s):  
Gear Tooth ◽  
Spur Gear ◽  
Tooth Root ◽  
Base Circle ◽  
Point Of Intersection

The purpose of this paper is to present an approach for the determination of geometry of spur gear tooth root fillet. An equation is developed to determine the point of tangency of involute profile and root fillet on the base circle for a spur gear without undercutting and the point of intersection of root fillet and involute profile above the base circle for an undercut gear. Generation using a hob or rack type cutter with protuberance (increase in tooth thickness at the tip of the hob tooth) is also discussed.

Determination of the ISO tooth form factor for involute spur and helical gears

1999 ◽  
Vol 34 (1) ◽  
pp. 89-103 ◽  
Author(s):  
J.I. Pedrero ◽  
A. Rueda ◽  
A. Fuentes
Keyword(s):  
Form Factor ◽  
Helical Gears ◽  
Tooth Form

Numerical Modelling of the Crack Propagation Path at Gear Tooth Root

2003 ◽  
Author(s):  
Damir T. Jelaska ◽  
Srecko Glodez ◽  
Srdjan Podrug
Keyword(s):  
Fatigue Crack ◽  
Service Life ◽  
Crack Propagation ◽  
Experimental Testing ◽  
Gear Tooth ◽  
Fatigue Crack Initiation ◽  
Propagation Path ◽  
Tooth Root ◽  
Stress Cycles

A numerical model for determination of service life of gears in regard to bending fatigue in a gear tooth root is presented. The Coffin-Manson relationship is used to determine the number of stress cycles Ni required for the fatigue crack initiation, where it is assumed that the initial crack is located at the point of the largest stresses in a gear tooth root. The simply Paris equation is then used for the further simulation of the fatigue crack growth, where required material parameters have been determined previously by the appropriate test specimens. The functional relationship between the stress intensity factor and crack length K = f(a), which is needed for determination of the required number of loading cycles Np for a crack propagation from the initial to the critical length, is obtained numerically. The total number of stress cycles N for the final failure to occur is then a sum N = Ni + Np. Although some influences were not taken into account in the computational simulations, the presented model seems to be very suitable for determination of service life of gears because numerical procedures used here are much faster and cheaper if compared with the experimental testing.

Bending Fatigue Analysis of PM Gears

2017 ◽  
Vol 754 ◽  
pp. 299-302 ◽  
Author(s):  
Srečko Glodež ◽  
Marko Šori
Keyword(s):  
Service Life ◽  
Computational Model ◽  
Gear Tooth ◽  
Tooth Root ◽  
Experimental Procedure ◽  
Bending Fatigue ◽  
Custom Made ◽  
Root Strength ◽  
Service Life Estimation

The paper discusses the computational and experimental approach for determination of the PM gears service life concerning bending fatigue in a gear tooth root. A proposed computational model is based on the stress-life approach where the stress field in a gear tooth root is determined numerically using FEM. The experimental procedure was done on a custom made back-to-back gear testing rig. The comparison between computational and experimental results has shown that the proposed computational approach is appropriate calculation method for service life estimation of sintered gears regarding tooth root strength. Namely, it was shown that in the case of proper heat treatment of tested gears, the tooth breakage occurred inside the interval with 95 % probability of failure, which has been determined using proposed computational model.

Immediate implantation in a patient with chronic generalized parodontitis and apical granuloma

2019 ◽  
Vol 24 (2) ◽  
pp. 145-149
Author(s):  
A. I. Musienko ◽  
K. I. Nesterova
Keyword(s):  
Tooth Extraction ◽  
Tooth Root ◽  
Duration Of Treatment ◽  
Promising Direction ◽  
Aesthetic Result ◽  
Bone Atrophy ◽  
Alveolar Tissue ◽  
High Level ◽  
Immediate Implantation

Relevance. Rehabilitation of patients with moderate to severe generalized periodontitis is a leading problem in periodontology. It was the determination of the prospects for immediate implantation in patients with chronic periodontitis, combined with the pathology of the tooth root and maxillary sinus.Materials and methods. A group of 94 people with periodontitis and chronic odontogenic rhinosinus was observed who underwent sinus surgical treatment, tooth extraction and one-stage implantation with FRP growth factor according to the author's technology.Results. The method showed high efciency on the basis of assessing the clinical, aesthetic result and restoration of bone density after surgery.Conclusions. The developed technology is a promising direction, it allows to combine a high level of sanation of alveolar tissue with the advantages of immediate implantation, prevents bone atrophy, helps reduce the duration of treatment and the number of surgical and orthopedic interventions.

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