Analytical procedure for the optimization of plastic gear tooth root

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.

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Dynamic characteristics of cracked gear and three-dimensional crack propagation analysis

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406212461326 ◽

2012 ◽

Vol 227 (6) ◽

pp. 1341-1361 ◽

Cited By ~ 11

Author(s):

Renping Shao ◽

Purong Jia ◽

Feifei Dong

Keyword(s):

Crack Propagation ◽

Dynamic Characteristics ◽

Gear Tooth ◽

Three Dimensional ◽

Beam Theory ◽

Circular Crack ◽

Propagation Path ◽

Tooth Root ◽

3D Crack Propagation ◽

Three Dimensional Finite Element

The dynamic model and three-dimensional finite element analytical model of cracked gear structure are established respectively according to the cracked beam theory, and the dynamic characteristics (natural frequency, vibration shape) of cracked gear body are investigated. Further the influences of crack position and crack length on the dynamic characteristics of gear structure are simulated and discussed. On this basis, the fracture and damage of gear structure are investigated according to the theory of fracture mechanics. Using FRANC3D software, the three-dimensional (3D) propagation of crack at tooth root for involute gear is simulated, and stress intensity factor (SIF)s of semi-circular crack at tooth root including three types are analyzed, their variation laws are gained, then the expressions of SIFs are obtained by numerical fitting FEM results. Based on this, the 3D crack propagation path at tooth root is simulated and discussed, then, it is verified by comparing to experimental results, according to the mutation of the maximum SIF at crack tip, the fracture and damage of gear tooth are judged, and its work life also is predicted. These have very important value for damage monitoring and diagnosis of gear.

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42CrMo Hard Surface Gear Intensity Tests and Modified Parameter Correction

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.246-247.145 ◽

2012 ◽

Vol 246-247 ◽

pp. 145-148

Author(s):

Nai Gen Li ◽

Nan Xu ◽

Nian Jun Zhang ◽

Meng Guo Zhu

Keyword(s):

Fatigue Strength ◽

Gear Tooth ◽

Coincidence Degree ◽

High Strength ◽

Tooth Root ◽

Bending Fatigue ◽

Hard Surface ◽

Basic Parameters ◽

Bending Fatigue Strength ◽

Research Intensity

Hard surface gears drive is considering mainly how to improve the tooth root bending fatigue strength and wear resistance of the teeth. Based on the analysis of sliding ratio, coincidence degree and the gear tooth root bending fatigue strength, basic parameters of gear can be modified to improve strength. Although these gears must be cut by the standard tools, high strength gears are needed in machinery. In this research, intensity experiments were conducted with 42CrMo modified and standard hard surface gears. Experiment results show that the improvements of 42CrMo gear parameters are effective and teeth strength is improved for the modified parameters of gears.

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

Journal of Mechanical Design ◽

10.1115/1.1427928 ◽

2001 ◽

Vol 124 (1) ◽

pp. 129-135 ◽

Cited By ~ 19

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.

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Study on vibration characteristics of a locomotive with gear tooth root crack by simulation

2016 Prognostics and System Health Management Conference (PHM-Chengdu) ◽

10.1109/phm.2016.7819813 ◽

2016 ◽

Cited By ~ 1

Author(s):

Zaigang Chen ◽

Jie Zhang ◽

Zichao Wang ◽

Tao Zhang ◽

Zhifang Zhu

Keyword(s):

Gear Tooth ◽

Vibration Characteristics ◽

Tooth Root ◽

Root Crack

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ESTIMATING SIZE OF GEAR TOOTH ROOT CRACK USING EMBEDDED MODELLING

Mechanical Systems and Signal Processing ◽

10.1006/mssp.2001.1452 ◽

2002 ◽

Vol 16 (5) ◽

pp. 841-852 ◽

Cited By ~ 20

Author(s):

C. JAMES LI ◽

HYUNGDAE LEE ◽

SUK HWAN CHOI

Keyword(s):

Gear Tooth ◽

Tooth Root ◽

Root Crack

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Crack Identification in Gear Tooth Root Using Adaptive Analysis

Advances in Fracture and Damage Mechanics VI - Key Engineering Materials ◽

10.4028/0-87849-448-0.697 ◽

2007 ◽

pp. 697-700

Author(s):

Ales Belsak ◽

Jože Flašker

Keyword(s):

Gear Tooth ◽

Crack Identification ◽

Tooth Root ◽

Adaptive Analysis

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

Volume 8: 11th International Power Transmission and Gearing Conference; 13th International Conference on Advanced Vehicle and Tire Technologies ◽

10.1115/detc2011-47404 ◽

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.

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