scholarly journals Lubricant and Additive Effects on Spur Gear Fatigue Life

1986 ◽  
Vol 108 (3) ◽  
pp. 468-475 ◽  
Author(s):  
D. P. Townsend ◽  
E. V. Zaretsky ◽  
H. W. Scibbe
Keyword(s):  
Fatigue Life ◽  
Statistical Difference ◽  
Spur Gear ◽  
Antiwear Additives ◽  
Spur Gears ◽  
Additive Effects ◽  
Viscosity Coefficients ◽  
Surface Fatigue ◽  
Load Carrying ◽  
Endurance Tests

Spur gear endurance tests were conducted with six lubricants using a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The sixth lubricant was divided into four batches each of which had a different additive content. Lubricants tested with a phosphorous-type load carrying additive showed a statistically significant improvement in life over lubricants without this type additive. The presence of sulphur type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears. No statistical difference in life was produced with those lubricants of different base stocks but with similar viscosity, pressure-viscosity coefficients and antiwear additives. Gears tested with a 0.1 wt percent sulfur and 0.1 wt percent phosphorus EP additives in the lubricant had reactive films that were 200 to 400 Å (0.8 to 1.6 μin) thick.

scholarly journals Lubricant and additive effects on spur gear fatigue life

1989 ◽  
Vol 6 (2) ◽  
pp. 83-106 ◽  
Author(s):  
D. P. Townsend ◽  
E. V. Zaretsky ◽  
H. W. Scibbe
Keyword(s):  
Fatigue Life ◽  
Spur Gear ◽  
Additive Effects

scholarly journals Endurance and Failure Characteristics of Modified Vasco X-2, CBS 600 and AISI 9310 Spur Gears

1981 ◽  
Vol 103 (2) ◽  
pp. 506-513 ◽  
Author(s):  
D. P. Townsend ◽  
E. V. Zaretsky
Keyword(s):  
Fatigue Tests ◽  
Tooth Surface ◽  
Spur Gears ◽  
Failure Characteristics ◽  
Surface Fatigue ◽  
Tooth Fracture ◽  
Rolling Element ◽  
Endurance Tests

Gear endurance tests and rolling-element fatigue tests were conducted to compare the performance of spur gears made from AISI 9310, CBS 600 and modified Vasco X-2 and to compare the pitting fatigue lives of these three materials. Gears manufactured from CBS 600 exhibited lives longer than those manufactured from AISI 9310. However, rolling-element fatigue tests resulted in statistically equivalent lives. Modified Vasco X-2 exhibited statistically equivalent lives to AISI 9310. CBS 600 and modified Vasco X-2 gears exhibited the potential tooth fracture occurring at a tooth surface fatigue pit. Case carburization of all gear surfaces for the modified Vasco X-2 gears results in fracture at the tips of the gears.

Performance enhancement of spur gear formed through asymmetric tooth

2019 ◽  
Vol 233 (9) ◽  
pp. 1361-1378 ◽  
Author(s):  
R Prabhu Sekar
Keyword(s):  
Wear Resistance ◽  
Performance Enhancement ◽  
Spur Gear ◽  
Spur Gears ◽  
Comparative Performance ◽  
Gear Design ◽  
Load Carrying ◽  
Gear Efficiency ◽  
Increasing Demand ◽  
The One

Tooth fracture and surface wear are the major failure causes in a gearing system. With increasing demand for high power density gear applications, the need of effective gear design becomes an important requirement to improve gear life. This article presents a method to enhance the load carrying capacity in bending and contact, as well as wear resistance to increase gear efficiency through asymmetric tooth. Asymmetric gear is the one whose pressure angles at pitch circle on drive and coast sides are different. In the present investigation, the load shared by a teeth pair, fillet and contact stresses, wear resistance, frictional power losses and the respective mechanical efficiencies have been determined for comparative performance assessment of symmetric and asymmetric spur gears.

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.

scholarly journals Mapping of scatter in fatigue life assessment of welded structures—a round-robin study

2021 ◽  
Author(s):  
Gustav Hultgren ◽  
Mansoor Khurshid ◽  
Peter Haglund ◽  
Zuheir Barsoum
Keyword(s):  
Fatigue Life ◽  
Round Robin ◽  
Life Assessment ◽  
Fatigue Life Assessment ◽  
Fatigue Life Estimation ◽  
Box Structures ◽  
Load Carrying ◽  
Local Stresses ◽  
Sources Of Variation ◽  
Global And Local

AbstractA round-robin study has been carried out within a national project in Sweden with the addition of an international participant, where several industrial partners and universities are participating. The project aims to identify variation and sources of variation in welding production, map scatter in fatigue life estimation, and define and develop concepts to reduce these, in all steps of product development. The participating organisations were asked to carry out fatigue life assessment of welded box structures, which is a component in load-carrying structures. The estimations of fatigue life have also been compared with fatigue test results. Detailed drawings, loads and material data were also given to the participants. The participants were supposed to use assessment methods based on global and local stresses using the design codes or recommendations they currently use in-house. Differences were identified between both methods and participants using the same codes/recommendations. Applicability and conditions from the cases in the codes were also identified to be differently evaluated between the participants. It could be concluded that for the applied cases the nominal stress method often overestimated the fatigue life and had a high scatter in the estimations by different participants. The effective notch method is conservative in comparison to the life of tested components with little scatter between the results derived by the participants.

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