Composite Fabric Blankets for Plastic Gears

2018 ◽  
Author(s):  
S. Kini ◽  
A. Fuentes Aznar ◽  
H. Ghoneim
Keyword(s):  
Gear Tooth ◽  
Load Capacity ◽  
Research Work ◽  
Maximum Level ◽  
Contact Stresses ◽  
Composite Surface ◽  
Tooth Surfaces ◽  
Bending Stresses ◽  
Future Work ◽  
Plastic Gears

Two approaches for increasing the load capacity of plastic gears in general are proposed and investigated: modifying the conventional involute profile of the gear tooth surfaces by applying a parabolic-crowned profile, and introducing a composite fabric, which blankets the surface of the teeth. The investigation is carried out using the finite element method (IGD/ANSYS). A five-tooth model is applied for the gears, and nylon and carbon/nylon are adopted for the materials. The evolution of maximum contact and bending stresses is evaluated over two cycles of meshing for both the pure plastic (nylon) gears and the gears with the composite surface blanket (carbon/nylon) to investigate the process of transfer of load between consecutive pairs of teeth and detect possible edge contacts. The results indicate that selecting the proper parabolic-crowned profile helps to alleviate the contact stress, and more specifically, to reduce the peaks of contact stresses due to edge contacts at the tip of the teeth. The results also indicate that there are an optimum parabolic-crowned profile and an optimum thickness of the composite blanket, which render the lowest maximum level of contact stresses over the cycle of meshing and bending stresses at the fillet. However, this preliminary research work suggests that, for the case considered, the novel idea of composite blanket is inconclusive — though the blanket may protect the plastic core, it itself becomes vulnerable to failure. The idea is being explored more, and the results will be disseminated in a future work.

Mathematical models of hobs for conjugate-curve gears having three contact points

2014 ◽  
Vol 229 (13) ◽  
pp. 2402-2411 ◽  
Author(s):  
Yan’e Gao ◽  
Bingkui Chen ◽  
Dong Liang
Keyword(s):  
Mathematical Models ◽  
Contact Stress ◽  
Gear Tooth ◽  
Load Capacity ◽  
Point Contact ◽  
Curvature Radius ◽  
Circular Arc ◽  
Normal Section ◽  
Contact Points ◽  
Tooth Surfaces

Conjugate-curve gears are the gears which are point contact and the locus curves of the contact points are conjugate curves. The contact pattern of the conjugate-curve gear tooth surfaces are convex to concave, which reduces the contact stress of the tooth surfaces due to the small value of the relative curvature radius at the contact point. The tubular tooth surfaces of the conjugate-curve gears have one pair of conjugate curves. To decrease the running-in time and increase the load capacity, the conjugate-curve gears having three pairs of conjugate curves are designed. The contact stress of the tooth surfaces having three contact points is much smaller than that of the tubular tooth surfaces in the computer contact analysis. For the further study of the performance of the conjugate-curves gears having three contact points, hobs are considered to manufacture the gears. Two mismatched rack cutters having three contact points are applied for the design of hobs. The working edge in the normal section profile of the rack cutter for the hob generating the pinion is a circular arc and the working edges in the normal section of the rack cutter for the hob generating the gear are two parabolic curves that are tangent to the convex circular arc. By applying the designed rack cutter profiles, the principle of coordinate transformation, the differential geometry theory, and the theory of gearing, mathematical models of the hobs are established. To verify the proposed tooth profile and the hobs, the experimental cutting trials and the load capacity test are carried out. The final accuracy of the gear satisfies the design requirements. The results demonstrate the feasible of the proposed design method.

scholarly journals Application of the Bilateral Filter for the Reconstruction of Spiral Bevel Gear Tooth Surfaces From Point Clouds

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Ignacio Gonzalez-Perez ◽  
Pedro L. Guirao-Saura ◽  
Alfonso Fuentes-Aznar
Keyword(s):  
Gear Tooth ◽  
Maximum Level ◽  
Bilateral Filter ◽  
Point Clouds ◽  
Bevel Gear ◽  
Spiral Bevel Gear ◽  
Tooth Contact Analysis ◽  
Contact Patterns ◽  
Tooth Surfaces ◽  
Spiral Bevel

Abstract Reconstruction of gear tooth surfaces from point clouds obtained by noncontact metrology machines constitutes a promising step forward not only for a fast gear inspection but also for reverse engineering and virtual testing and analysis of gear drives. In this article, a new methodology to reconstruct spiral bevel gear tooth surfaces from point clouds obtained by noncontact metrology machines is proposed. The need of application of a filtering process to the point clouds before the process of reconstruction of the gear tooth surfaces has been revealed. Hence, the bilateral filter commonly used for 3D object recognition has been applied and integrated in the proposed methodology. The shape of the contact patterns and the level of the unloaded functions of transmission errors are considered as the criteria to select the appropriate settings of the bilateral filter. The results of the tooth contact analysis of the reconstructed gear tooth surfaces show a good agreement with the design ones. However, stress analyses performed with reconstructed gear tooth surfaces reveal that the maximum level of contact pressures is overestimated. A numerical example based on a spiral bevel gear drive is presented.

scholarly journals Operating behavior and performance of oil-lubricated plastic gears

2021 ◽  
Author(s):  
C. M. Illenberger ◽  
T. Tobie ◽  
K. Stahl
Keyword(s):  
Material Properties ◽  
Load Capacity ◽  
Research Work ◽  
Experimental Studies ◽  
Experimental Investigations ◽  
Market Shares ◽  
Large Numbers ◽  
And Performance ◽  
Tooth Flank ◽  
Plastic Gears

AbstractPlastic gears and their numerous applications have become an integral part of industrial practice. In particular, the ability to produce large numbers of gears cost-effectively using injection molding techniques is making a significant contribution to growing market shares. Compared to conventional steel materials, however, the material properties of thermoplastics differ fundamentally. In particular, the high temperature dependence of the material properties and the lower strength pose challenges for designers. Against this background, theoretical and experimental studies on the operating and service life behavior of different thermoplastic materials have been conducted and evaluated. In addition to theoretical investigations on the tooth flank load carrying capacity, comprehensive measurements on temperature behavior were carried out and compared to common methods of temperature calculation for plastic gears. Experimental investigations on the tooth flank load capacity by means of back-to-back tests of different materials and their evaluation show the potential of thermoplastic materials for the application in power transmitting drivetrains. This contribution will give an overview of the performed research work and summarizes main results of these studies.

Contact Stress and Root Stress Analyses of Thin-Rimmed Spur Gears With Inclined Webs

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Shuting Li
Keyword(s):  
Contact Stress ◽  
Contact Stresses ◽  
Spur Gears ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Contact Patterns ◽  
Tooth Surfaces ◽  
Bending Stresses ◽  
The Right ◽  
The Web

Loaded tooth contact analysis (LTCA), deformation, and stress calculations of three types of thin-rimmed spur gears with inclined webs at the left side, the center, and the right side of the tooth are conducted in this paper with finite element methods (FEM) combined with a mathematical programming method when these gears are engaged with a solid mating gear. The contact stresses on the tooth surfaces, the bending stresses at the tooth roots, and the joint stresses of the rim and the web are analyzed as the web position and the web angle are changed. It was found that the web position and the web angle of the thin-rimmed gears have a significant effect on the tooth contact stresses, the root bending stresses, and the joint stresses. The maximum contact stress of the right web gear becomes very small when the web is inclined from 0 to 30 deg, and it increases again when the web angles are changed from 45 to 60 deg. This interesting relationship between the web angle and the tooth contact stresses of thin-rimmed right inclined web gears is used to absorb the misalignment errors in the gears and improve the partial tooth contact pattern resulting from the misalignment errors. A calculation example is provided to illustrate how to improve the partial tooth contact patterns in gears with misalignment errors.

scholarly journals Contact Stresses and Bending stresses for Worm & Helical Gear

2019 ◽  
Vol 8 (4) ◽  
pp. 11326-11328
Keyword(s):  
Contact Stress ◽  
Applied Load ◽  
Gear Tooth ◽  
Helical Gear ◽  
Contact Stresses ◽  
Bending Stress ◽  
Surface Strength ◽  
Face Width ◽  
The Face ◽  
Bending Stresses

Surface Strength of the gear tooth depends on the contact stress and the bending stress caused due to the applied load on the tip of its gear tooth. Analysis has become popular in decreasing the failures. Fatigue causes in the root bending stress and Surface indentation causes in the contact stress. Then modified Lewis beam strength is used for bending stress and the AGMA method is used for contact stresses by varying the face width. Analytical results are based on Lewis formula and the theoretical values were calculated by AGMA standard so the results were validated.

A Novel Method for Calculation Gear Tooth Stiffness for Dynamic Analysis of Spur Gears With Asymmetric Teeth

2014 ◽  
Author(s):  
F. Karpat ◽  
O. Dogan ◽  
S. Ekwaro-Osire ◽  
C. Yuce
Keyword(s):  
Gear Tooth ◽  
Load Capacity ◽  
Operating Conditions ◽  
Spur Gears ◽  
Finite Elements Analysis ◽  
Gear Teeth ◽  
Research Activities ◽  
Tooth Surfaces ◽  
Tooth Stiffness ◽  
Tooth Flank

Recently, there have been a number of research activities on spur gears with asymmetric teeth. The benefits of asymmetric gears are: higher load capacity, reduced bending and contact stress, lower weight, lower dynamic loads, reduced wear depths on tooth flank, higher reliability, and higher efficiency. Each of the benefits can be obtained through asymmetric teeth designed correctly. Gears operate in several conditions, such as inappropriate lubrication, excessive loads and installation problems. In working conditions, damage can occur in tooth surfaces due to excessive loads and unsuitable operating conditions. One of the important parameters of the tooth is stiffness, which is found to be reduced proportionally to the severity of the defect by asymmetric tooth design as described in this paper. The estimation of gear stiffness is an important parameter for determining loads between the gear teeth when two sets of teeth are in contact. In this paper, a 2-D tooth model is developed for finite elements analysis. A novel formula is derived from finite element results in order to estimate tooth stiffness depending on the tooth number and pressure angle on the drive side. Tooth stiffness for spur gears with asymmetric teeth is calculated and the results were compared with well known equations in literature.

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.

Tooth geometry and bending stress analysis of conjugate meshing face-gear pairs

2012 ◽  
Vol 227 (6) ◽  
pp. 1302-1314 ◽  
Author(s):  
Zihni B Saribay
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Gear Tooth ◽  
Spur Gear ◽  
Gear Pair ◽  
Bending Stress ◽  
Face Gear ◽  
Element Analysis ◽  
Tooth Surfaces ◽  
Bending Stresses

The conjugate meshing face-gear pairs are implemented to high shaft angle intersecting axis gears such as the pericyclic transmission system. The meshing face-gear pair tooth surfaces are generated with a mutually conjugate spur shaper. The established tooth geometry and the dimensions of the conjugate face-gear pairs are summarized in this article. Four different example face-gear pairs are generated at various shaft angles and numbers of tooth combinations. Tooth bending stresses of these face-gear pair teeth are investigated based on finite element analysis methods. In these analyses, only single pairs of teeth are investigated. These results are compared to analog the spur gear tooth bending stresses calculated by finite element analysis and standard spur gear stress formulas. Meshing face-gear pair single tooth bending stress levels show approximately 3% to 6% difference from same size spur gear tooth.

scholarly journals Computerized Design and Generation of Low-Noise Helical Gears with Modified Surface Topology

1995 ◽  
Vol 117 (2A) ◽  
pp. 254-261 ◽  
Author(s):  
F. L. Litvin ◽  
N. X. Chen ◽  
J. Lu ◽  
R. F. Handschuh
Keyword(s):  
Gear Tooth ◽  
Error Function ◽  
Transmission Error ◽  
Low Noise ◽  
Surface Topology ◽  
Helical Gears ◽  
Transmission Errors ◽  
Bearing Contact ◽  
Pinion Gear ◽  
Tooth Surfaces

An approach for the design and generation of low-noise helical gears with localized bearing contact is proposed. The approach is applied to double circular arc helical gears and modified involute helical gears. The reduction of noise and vibration is achieved by application of a predesigned parabolic function of transmission errors that is able to absorb a discontinuous linear function of transmission errors caused by misalignment. The localization of the bearing contact is achieved by the mismatch of pinion-gear tooth surfaces. Computerized simulation of meshing and contact of the designed gears demonstrated that the proposed approach will produce a pair of gears that has a parabolic transmission error function even when misalignment is present. Numerical examples for illustration of the developed approach are given.

Identification and Minimization of Deviations of Real Gear Tooth Surfaces

1989 ◽  
Author(s):  
F. L. Litvin ◽  
Y. Zhang ◽  
J. Kieffer ◽  
R. F. Handschuh
Keyword(s):  
Machine Tool ◽  
Gear Tooth ◽  
Real Surface ◽  
The Real ◽  
Tooth Surfaces ◽  
Coordinate Measurements

Abstract The authors propose an approach that uses coordinate measurements of the real surface to: (i) determine the real applied machine-tool settings, (ii) determine the deviations of the real surface from the theoretical one, (iii) minimize the deviations by correction of the machine-tool settings, and (iv) represent the real surface analytically in the same Gaussian coordinates as the theoretical one.

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