scholarly journals Compliance and Stress Sensitivity of Spur Gear Teeth

1981 ◽  
Vol 103 (2) ◽  
pp. 447-459 ◽  
Author(s):  
R. W. Cornell
Keyword(s):  
Closed Form Solution ◽  
Time History ◽  
Peak Stress ◽  
Spur Gear ◽  
Stress Sensitivity ◽  
Form Solution ◽  
Sensitivity Analyses ◽  
Spur Gears ◽  
Contact Ratio ◽  
Gear Teeth

The magnitude and variation of tooth pair compliance with load position affects the dynamics and loading significantly, and the tooth root stressing per load varies significantly with load position. Therefore, the recently developed time history, interactive, closed form solution for the dynamic tooth loads for both low and high contact ratio spur gears [1] was expanded to include improved and simplified methods for calculating the compliance and stress sensitivity for three involute tooth forms as a function of load position. The compliance analysis is based on Weber [2] and O’Donnell [3] but with an improved fillet/foundation compliance analysis. The stress sensitivity analysis is a modified version of the Heywood method [4] but with an improvement in the magnitude and location of the peak stress in the fillet. These improved compliance and stress sensitivity analyses are presented along with their evaluation using test, finite element, and analytic transformation results, which showed good agreement.

scholarly journals Dynamic Tooth Loads and Stressing for High Contact Ratio Spur Gears

1978 ◽  
Vol 100 (1) ◽  
pp. 69-76 ◽  
Author(s):  
R. W. Cornell ◽  
W. W. Westervelt
Keyword(s):  
Dynamic Model ◽  
Gear Tooth ◽  
Closed Form Solution ◽  
Time History ◽  
Spur Gear ◽  
Form Solution ◽  
Tooth Profile ◽  
Contact Ratio ◽  
Modification System ◽  
Work Done

A time history, closed form solution is presented for a dynamic model of spur gear systems for all practical contact ratios. The analysis determines the dynamic response of the gear system and the associated tooth loads and stressing. The dynamic model is based on work done by Richardson and Howland [2, 3], and assumes the two gears act as a rigid inertia and the teeth act as a variable spring of a dynamic system excited by the meshing action of the teeth. Included in the analysis are the effects of the non-linearity of the tooth pair stiffness during mesh, the tooth errors, and the tooth profile modifications. Besides reviewing the features, solution, and program of this analysis, preliminary results from applying the analysis are presented, which show that tooth profile modification, system inertia and damping, and system critical speeds can affect the dynamic gear tooth loads and stressing significantly.

Studies on the Dynamic Performance of a Spur Gear With Hollow Teeth

1992 ◽  
Author(s):  
A. Ramamohana Rao ◽  
B. Srinivasulu
Keyword(s):  
Damping Ratio ◽  
Dynamic Performance ◽  
Spur Gear ◽  
Dynamic Loads ◽  
Response Analysis ◽  
Spur Gears ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Direction Parallel ◽  
Gear Teeth

Abstract Performance of spur gears largely depends on the magnitude and nature of variation of dynamic loads occuring between mating teeth. Variable tooth mesh stiffness is one of the primary sources causing parametric excitations resulting in dynamic loads. The usual method of varying the mesh stiffness to reduce dynamic loads is to use high contact ratio and profile modified gears. In this paper, a new type of tooth design to improve the dynamic performance of spur gears is presented. In this, a through hole is drilled in each tooth in a direction parallel to the gear axis. The diameter of the hole and its position on the tooth centre line are variable. Such a gear is called a hollow gear. Dynamic analysis is carried out for the mesh of hollow pinions mating with solid gears. The results are compared with solid pinions (no holes in teeth) meshing with solid gears. Finite element method is used for the analysis. For estimation of the dynamic load variation in hollow-solid and solid-solid gear meshes, a model incorporating the varying mesh stiffness and damping of gear teeth is used. Governing differential equations are solved using unconditionally stable Newmark-beta algorithm. The dynamic loads obtained are used as an input time varying loads for the determination of dynamic fillet and hole stress response of solid and hollow gear teeth whichever is applicable. Modal superposition technique is used for transient response analysis. The study shows that for the same damping ratio, dynamic loads in hollow-solid meshes are nearly the same as in a solid-solid mesh. In reality, the dynamic loads in a hollow-solid mesh are less than a solid-solid mesh due to its inherent higher material damping.

Tooth Load Sharing in High-Contact Ratio Spur Gears

1985 ◽  
Vol 107 (1) ◽  
pp. 11-16 ◽  
Author(s):  
A. H. Elkholy
Keyword(s):  
Contact Stress ◽  
Applied Load ◽  
Normal Load ◽  
Closed Form Solution ◽  
Load Sharing ◽  
Form Solution ◽  
Spur Gears ◽  
Contact Ratio ◽  
Profile Modification ◽  
The Individual

A closed-form solution is presented for calculating the load sharing among meshing teeth in high contact ratio gearing (HCRG). The procedure is based upon the assumption that the sum of the tooth deflection, profile modification and spacing error at each of two or three pairs of contacts are all equal. It is also assumed that the sum of the normal loads contributed by each of two or three pairs of contacts is equal to the maximum normal load. Once the individual loads are determined, the tooth fillet stress, contact stress may be determined from the applied load and tooth geometry. An experimental example appears to verify the method.

Dynamic Analysis of High-Contact-Ratio Spur Gears With Asymmetric Teeth

2008 ◽  
Author(s):  
F. Karpat ◽  
S. Ekwaro-Osire
Keyword(s):  
Numerical Technique ◽  
Spur Gear ◽  
Dynamic Loads ◽  
Spur Gears ◽  
Load Carrying Capacity ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Gear Teeth ◽  
Load Carrying ◽  
Gear Contact

In this research, a numerical technique is used to study the performance of high-contact-ratio (HCR) spur gears with asymmetric teeth. Asymmetric teeth have been shown to minimize dynamic loads and to increase the load carrying capacity. This is due to the fact that these teeth have a larger pressure angle on the drive side compared to the coast side. In literature, symmetric gear teeth with HCR have been shown to also yield low dynamic loads and high load capacities. HCR gears have these positive attributes because for gears in a mesh, the number of tooth pairs sharing the transmitted load alternates between two and three. In this study, the separate benefits of an HCR gear and asymmetric teeth are unified into a spur gear with asymmetric teeth. In this case, the effect of the gear contact ratio, addendum factor, mesh stiffness, pressure angles, and operation speeds on dynamic tooth loads are considered. The influences of these parameters on dynamic response are presented and discussed. A comparison between standard and non standard gear pairs in literature is also presented, with respect to dynamic tooth loads. Sample simulation results, which were obtained by using an in-house computer program, are discussed. The results obtained are shown to match well with some related analytical and experimental results in literature. It is further demonstrated that HCR spur gears with asymmetric teeth do provide a marked advantage compared to the conventional spur gears with symmetric teeth.

Effect of change of contact ratio on contact fatigue stress of involute spur gears

2018 ◽  
Vol 8 (3) ◽  
Author(s):  
Michael Gebremariam ◽  
Ashish Thakur ◽  
Equbamariam Leake ◽  
Daniel Tilahun
Keyword(s):  
Applied Load ◽  
Contact Fatigue ◽  
Spur Gear ◽  
Spur Gears ◽  
Contact Ratio ◽  
Gear Teeth ◽  
Fatigue Stress ◽  
Solid Works ◽  
To Come ◽  
Ansys Workbench

This paper dealt on the effect of change of contact ratio on the contact fatigue stresses generated on meshing involute spur gear teeth during operation. In this study, different cases of six contact ratio gearing between and have been analyzed. For each contact ratio the rate of load sharing and angular and radial position of load were determined on the involute profile of meshing tooth of each gearing to determine contact fatigue stress at critical condition. To come up at the result CATIA and Solid Works software involute spur gear models have been developed for stress analysis on ANSYS Workbench (FEM). Because of the decrease in value and the change in location and direction of applied load, higher contact ratio gearing resulted higher generated tooth fatigue contact stress life. The results obtained from ANSYS Workbench are compared with results of the AGMA gear formula results.

The Compliance of Solid, Wide-Faced Spur Gears

1990 ◽  
Vol 112 (4) ◽  
pp. 590-595 ◽  
Author(s):  
J. H. Steward
Keyword(s):  
Experimental Data ◽  
Contact Line ◽  
Load Distribution ◽  
3D Model ◽  
Spur Gear ◽  
Point Load ◽  
Spur Gears ◽  
Line Load ◽  
Gear Teeth ◽  
Theoretical Results

In this paper, the requirements for an accurate 3D model of the tooth contact-line load distribution in real spur gears are summarized. The theoretical results (obtained by F.E.M.) for the point load compliance of wide-faced spur gear teeth are set out. These values compare well with experimental data obtained from tests on a large spur gear (18 mm module, 18 teeth).

scholarly journals Study of Lubricant Jet Flow Phenomena in Spur Gears

1975 ◽  
Vol 97 (2) ◽  
pp. 283-288 ◽  
Author(s):  
L. S. Akin ◽  
J. J. Mross ◽  
D. P. Townsend
Keyword(s):  
Motion Picture ◽  
High Speed ◽  
Drop Size ◽  
Gear Tooth ◽  
Jet Flow ◽  
Spur Gear ◽  
Spur Gears ◽  
Gear Teeth ◽  
Flow Phenomena ◽  
Oil Jet

Lubricant jet flow impingement and penetration depth into a gear tooth space were measured at 4920 and 2560 using a 8.89-cm- (3.5-in.) pitch dia 8 pitch spur gear at oil pressures from 7 × 104 to 41 × 104 N/m2 (10 psi to 60 psi). A high speed motion picture camera was used with xenon and high speed stroboscopic lights to slow down and stop the motion of the oil jet so that the impingement depth could be determined. An analytical model was developed for the vectorial impingement depth and for the impingement depth with tooth space windage effects included. The windage effects on the oil jet were small for oil drop size greater than 0.0076 cm (0.003 in.). The analytical impingement depth compared favorably with experimental results above an oil jet pressure of 7 × 104 N/m2 (10 psi). Some of this oil jet penetrates further into the tooth space after impingement. Much of this post impingement oil is thrown out of the tooth space without further contacting the gear teeth.

scholarly journals Baseline Experimental Results on the Effect of Oil Temperature on Shrouded Meshed Spur Gear Windage Power Loss

2017 ◽  
Author(s):  
Irebert R. Delgado ◽  
Michael J. Hurrell
Keyword(s):  
Experimental Test ◽  
Power Loss ◽  
Spur Gear ◽  
Spur Gears ◽  
Test Results ◽  
Oil Viscosity ◽  
Gear Teeth ◽  
Temperature Load ◽  
Loss Efficiency

Rotorcraft gearbox efficiencies are reduced at increased surface speeds due to viscous and impingement drag on the gear teeth. This windage power loss can affect overall mission range, payload, and frequency of transmission maintenance. Experimental and analytical studies on shrouding for single gears have shown it to be potentially effective in mitigating windage power loss. Efficiency studies on unshrouded meshed gears have shown the effect of speed, oil viscosity, temperature, load, lubrication scheme, etc. on gear windage power loss. The open literature does not contain experimental test data on shrouded meshed spur gears. Gear windage power loss test results are presented on shrouded meshed spur gears at elevated oil inlet temperatures and constant oil pressure both with and without shrouding. Shroud effectiveness is compared at four oil inlet temperatures. The results are compared to the available literature and follow-up work is outlined.

Determining the Lewis Factor for Plastic Spur Gears With Asymmetric Teeth

2009 ◽  
Author(s):  
J. L. Moya ◽  
A. S. Machado ◽  
A. M. Becerra ◽  
J. A. Vela´zquez ◽  
R. Goytisolo
Keyword(s):  
Theoretical Analysis ◽  
Direct Effect ◽  
Spur Gear ◽  
Spur Gears ◽  
Gear Teeth ◽  
Tooth Fracture ◽  
Tooth Width

The basic weakness of plastic spur gear teeth is tooth fracture brought on by the accumulation of stress at the root of the tooth and by the geometry of the tooth. Tooth width and height play a major role in failure, as does the Lewis factor, which has a direct effect on the expression to calculate tooth strength. This study describes a theoretical analysis of a procedure to determine the Lewis factor for asymmetric teeth.

scholarly journals Gear Teeth Deflection Model for Spur Gears: Proposal of a 3D Nonlinear and Non-Hertzian Approach

Machines ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 223
Author(s):  
Fabio Bruzzone ◽  
Tommaso Maggi ◽  
Claudio Marcellini ◽  
Carlo Rosso
Keyword(s):  
A Priori ◽  
Three Dimensional ◽  
Spur Gear ◽  
Test Case ◽  
Spur Gears ◽  
Three Dimensional Model ◽  
Gear Teeth ◽  
Face Width ◽  
Mechanics Model ◽  
Pressure Distributions

In this paper, a three-dimensional model for the estimation of the deflections, load sharing attributes, and contact conditions will be presented for pairs of meshing teeth in a spur gear transmission. A nonlinear iterative approach based on a semi-analytical formulation for the deformation of the teeth under load will be employed to accurately determine the point of application of the load, its intensity, and the number of contacting pairs without a priori assumptions. At the end of this iterative cycle the obtained deflected shapes are then employed to compute the pressure distributions through a contact mechanics model with non-Hertzian features and a technique capable of obtaining correct results even at the free edges of the finite length contacting bodies. This approach is then applied to a test case with excellent agreement with its finite element counterpart. Finally, several results are shown to highlight the influence on the quasi-static behavior of spur gears of different kinds and amounts of flank and face-width profile modifications.

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