An Approach for Solving the Contact Problem in Spur Gear Transmissions Considering Gear Misalignments

2015 ◽  
Author(s):  
V. Roda-Casanova ◽  
F. Sanchez-Marin ◽  
J. L. Iserte
Keyword(s):  
Contact Problem ◽  
Computational Cost ◽  
Element Model ◽  
Spur Gear ◽  
New Approach ◽  
Load Distributions ◽  
Bending Stresses ◽  
Gear Drives ◽  
Contact Pressures

Gear misalignments originate unwanted uneven load distributions that increase contact pressures and the bending stresses, reducing the service life of gear drives. Therefore, it is very important to take into account the misalignments in the determination of contact pressures when designing a gear transmission. Some of these misalignments are related to manufacturing and assembly errors, but others are produced by the deformation of the shafts when power is transmitted. These deformations cause misalignment of the gears, modifying the contact bearing and the pressure distribution, which modifies the deformation of the shafts, leading to a coupled problem not always easy to solve. In this work, a new approach to solve this problem is proposed, based on an iterative algorithm which uncouples the determination of the deformation of the shafts from the contact problem. The proposed approach has been tested through various configurations of spur gear drives. The obtained results are compared with those obtained using a finite element model, showing a good correlation between them, but with a significant reduction of the computational cost.

Implementation of a Finite Element Model for Gear Stress Analysis Based on Tie-Surface Constraints and Its Validation Through the Hertz's Theory

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Ignacio Gonzalez-Perez ◽  
Alfonso Fuentes-Aznar
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Element Model ◽  
Gear Drive ◽  
Bearing Contact ◽  
Stress Maximum ◽  
Bending Stresses ◽  
Gear Drives ◽  
Surface Constraints

A new finite element model for stress analysis of gear drives is proposed. Tie-surface constraints are applied at each tooth of the gear model to obtain meshes that can be independently defined: a finer mesh at contact surfaces and fillet and a coarser mesh in the remaining part of the tooth. Tie-surface constraints are also applied for the connection of several teeth in the model. The model is validated by application of the Hertz's theory in a spiral bevel gear drive with localized bearing contact and by observation of convergency of contact and bending stresses. Maximum contact pressure, maximum Mises stress, maximum Tresca stress, maximum major principal stress, and loaded transmission errors are evaluated along two cycles of meshing. The effects of the boundary conditions that models with three, five, seven, and all the teeth of the gear drive provide on the above-mentioned variables are discussed. Several numerical examples are presented.

Enhanced Approach for Application of Longitudinal Plunging in Manufacturing of Spur Gear Drives

2003 ◽  
Author(s):  
Claudio Zanzi ◽  
Jose´ I. Pedrero
Keyword(s):  
Manufacturing Process ◽  
Spur Gear ◽  
Numerical Examples ◽  
Bearing Contact ◽  
Bending Stresses ◽  
Gear Drives ◽  
Curvilinear Trajectory

This paper represents an enhanced approach for application of longitudinal plunging in the manufacturing process of spur gear drives in order to localize the bearing contact. The proposed approach is based on application of a grinding disk performing a planar curvilinear trajectory. The main innovation is the tilt of the plane containing the curvilinear trajectory performed by the center of the grinding disk. The proposed manufacturing process allows the following improvements to be obtained: (i) uniform length of the major axes of the instantaneous contact ellipses all over the path of contact, (ii) reduced sensitivity of the shift of the path of contact to errors of alignment, and (iii) reduced level of contact and bending stresses. Numerical examples of design are represented.

Finite element method analysis of a spur gear with a corrected profile

2007 ◽  
Vol 42 (5) ◽  
pp. 281-292 ◽  
Author(s):  
A Pasta ◽  
G Virzí Mariotti
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
Spur Gear ◽  
Material Strength ◽  
Mechanical Resistance ◽  
Spur Gears ◽  
The Difference ◽  
Element Method

The difference between the stress value calculated by a two-dimensional finite element model of spur gears and those obtained by the rules in ISO 6336 was evaluated. Hertz theory, which provides information on the extension of the contact area and the maximum value of the contact pressure, was used to choose the dimensions of the elements. The mesh was created using the stress analytical solution relative to a model consisting of two cylinders in contact. Analogous optimization was executed for the mesh of the teeth feet; a mesh of 15 elements was considered optimum, because it minimized the difference to 0.5 per cent in the bending stress calculation. Stress values, obtained using the finite element method (FEM), are generally lower than those obtained with the ISO rules. Hence, this approach yields a conservative determination of the effective material strength. In all the examined cases, the difference was less than 2.5 per cent. The set FEM technique gives a result accuracy of better than 1 per cent; the difference between the stress obtained by FEM and those obtained by ISO 6336 is less than 2.5 per cent, so that the FEM confirmed, consistent with the ISO rules, that correction of the profile results in significant benefits with respect to determination of the mechanical resistance of spur gears.

Die Shape Optimal Design in Bimetal Extrusion by the Finite Element Method

1997 ◽  
Vol 119 (2) ◽  
pp. 143-150 ◽  
Author(s):  
S. M. Byon ◽  
S. M. Hwang
Keyword(s):  
Finite Element ◽  
Optimal Design ◽  
Optimization Problem ◽  
Element Model ◽  
The Finite Element Method ◽  
Constrained Optimization Problem ◽  
New Approach ◽  
The Core ◽  
The Finite Element Model

A new approach to die shape optimal design in bimetal extrusion of rods is presented. In this approach, the design problem is formulated as a constrained optimization problem incorporated with the finite element model, and optimization of the die shape is conducted on the basis of the design sensitivities. The approach is applied to the determination of the optimal die shapes for several combinations of the core and sleeve materials.

Determination of Maximum Possible Contact Ratios for Spur Gear Drives With Small Number of Teeth

1995 ◽  
Author(s):  
M. A. Sahir Arikan
Keyword(s):  
Spur Gear ◽  
Number Of Teeth ◽  
Fillet Radius ◽  
Gear Drives

Abstract Maximum possible contact ratios which can be obtained by making use of x-zero gear pairs are determined for spur gear drives with small number of teeth. Rack cutter tip fillet radius and rack cutter geometry are taken into consideration in the analysis. Results for gear drives with various numbers of teeth and cut by rack cutters standardized by ISO and AGMA are given in forms of tables. Results are also compared with addendum modification coefficients recommended by ISO.

Optimization Design for Spur Gear with Stress-Relieving Holes

2015 ◽  
Vol 12 (02) ◽  
pp. 1550006
Author(s):  
Pham Van Thoan ◽  
Guilin Wen ◽  
Hanfeng Yin ◽  
Hieu Ld ◽  
Van Sy Nguyen
Keyword(s):  
Finite Element ◽  
Optimization Design ◽  
Design Method ◽  
Computational Cost ◽  
Element Model ◽  
Spur Gear ◽  
Element Analysis ◽  
Design Objective ◽  
Stress Relieving ◽  
Polynomial Response Surface

By designing stress-relieving holes in the stressed zone, an optimization design for reduction of root fillet stress in spur gear is presented based on the stress redistribution techniques. The design method consists of two parts as follows. In the first part, a finite element model that is combined with two gear segments for pinion gear and driven gear is built and the bending stress is analyzed. In the second part, the sizes and the locations of the stress-relieving holes of the gear teeth are optimized in order to reduce the root fillet stress. In the procedures of optimization design, the numerical simulation results by using Ansys Workbench are first used to construct the metamodels which can reduce the computational cost of the finite element analysis (FEA). In the metamodeling process, the optimal Space-Filling design (SFD) method is employed for the selection of sampling design points in design space, and the polynomial response surface (PRS) is utilized to formulate the design objective σmax. Based on the metamodels of the design objective, the genetic algorithm (GA) methodology is employed to find out the optimized locations and sizes of the holes at the root fillet. An illustrated example shows that the maximum principal stress in gear root fillet has been reduced by 14.69% based on the proposed optimization design. This implies the feasibility of the optimization design for increasing the life of gear by designing stress-relieving holes.

scholarly journals Determination of the ISO face load factor in spur gear drives by the finite element modeling of gears and shafts

2013 ◽  
Vol 65 ◽  
pp. 1-13 ◽  
Author(s):  
Victor Roda-Casanova ◽  
Francisco T. Sanchez-Marin ◽  
Ignacio Gonzalez-Perez ◽  
Jose L. Iserte ◽  
Alfonso Fuentes
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Spur Gear ◽  
Load Factor ◽  
Element Modeling ◽  
Gear Drives

A Finite Element Model for Consideration of the Torsional Effect on the Bearing Contact of Gear Drives

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Ignacio Gonzalez-Perez ◽  
Victor Roda-Casanova ◽  
Alfonso Fuentes ◽  
Francisco T. Sanchez-Marin ◽  
Jose L. Iserte
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Gear Tooth ◽  
Element Model ◽  
Element Analysis ◽  
Bearing Contact ◽  
Torque Transmission ◽  
Tooth Surfaces ◽  
Bending Stresses ◽  
Gear Drives

The finite element method is widely applied for the determination of contact and bending stresses in gear drives. It is based on the finite element model of the gear drive that is built by the discretization of the pinion and gear teeth and usually does not take into account the supporting components of the gears, as shafts, their bearings, or the gear case. Such components have an important influence in the formation of the bearing contact due to their deformations under load. Recently, some improved models have been proposed for finite element analysis of gear drives including their shafts. Those models have allowed shaft deflections to be taken into account for the investigation of formation of the bearing contact under load and its influence on bending and contact stresses. In this paper, an enhanced finite element model that takes into account not only the shaft deflections but also the torsional deformation of gear tooth surfaces due to torque transmission is proposed. Some numerical examples have been included.

The Mechanical Efficiency of Epicyclic Gear Trains

1993 ◽  
Vol 115 (3) ◽  
pp. 645-651 ◽  
Author(s):  
E. Pennestri` ◽  
F. Freudenstein
Keyword(s):  
Mechanical Efficiency ◽  
Spur Gear ◽  
Efficiency Analysis ◽  
Gear Drive ◽  
Epicyclic Gear ◽  
Gear Trains ◽  
Gear Drives ◽  
General Computer Program ◽  
General Computer

The analysis of mechanical efficiency constitutes an important phase in the design analysis of gear drives. The objective of this investigation has been the development of a general algorithm for the determination of efficiency in split-power spur-gear trains. The model includes meshing losses only; for a more realistic estimation other sources can be considered separately. The systematic nature of the formulation, based on the dual correspondence between the kinematic structure of the gear drive and a labelled graph, allows a ready coding of the efficiency analysis in a general computer program. The numerical results are in line with those given by other authors using different methodologies.

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