Some Observations on Scuffing in Tapered Roller Bearings

1998 ◽  
Vol 120 (3) ◽  
pp. 427-435 ◽  
Author(s):  
Harry Zantopulos

Tests were run on tapered roller bearings under severe operating conditions to promote the incidence of scuffing. This resulted in varying degrees of scuffing damage on the cone (inner race) ribs and/or spherical roller ends of some of the bearings. These were then examined using both the optical microscope and the scanning electron microscope (SEM). In addition, metallographic examinations were conducted on some of the damaged areas. On the basis of these observations, a qualitative model for the onset of scuffing is outlined. The quantitative data obtained from these tests was then analyzed in terms of Blok’s critical temperature criterion and also the scuffing criterion of the form WVx = constant.

Author(s):  
I Bercea ◽  
D Nélias ◽  
S Cretu

A method to determine the optimum value of the initial axial compression or preload between two tapered roller bearings has been described in Part 1 of this paper. The optimization consists in maximizing the fatigue life of the bearing arrangement. The method is applied here to the transfer shaft of an automobile automatic transaxle, and the results are analysed. Numerical results show the importance of an adequate axial compression to ensure a maximum bearing arrangement reliability for a complex cycle of operating conditions in terms of load and speed.


Author(s):  
G. R. Higginson ◽  
R. H. Leaver

A new test rig is used to investigate the mode of lubrication of tapered roller bearings under axial loading. Two different bearing configurations for a 21/4-in shaft are used. The lubricants are mineral oils. The investigation establishes the nature of the lubrication at the load-carrying points in the bearing, at the inner and outer rings, and at the flange on the inner ring. Measurements of friction losses are made over a wide range of operating conditions; these are analysed theoretically, and are substantially accounted for by modern lubrication theory and a detailed consideration of the geometry of the bearings as a whole.


Lubricants ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 67
Author(s):  
Sven Wirsching ◽  
Max Marian ◽  
Marcel Bartz ◽  
Thomas Stahl ◽  
Sandro Wartzack

In the context of targeted improvements in energy efficiency, secondary rolling bearing contacts are gaining relevance. As such, the elastohydrodynamically lubricated (EHL) roller face/rib contact of tapered roller bearings significantly affects power losses. Consequently, this contribution aimed at numerical optimization of the pairing’s macro-geometric parameters. The latter were sampled by a statistical design of experiments (DoE) and the tribological behavior was predicted by means of EHL contact simulations. For each of the geometric pairings considered, a database was generated. Key target variables such as pressure, lubricant gap and friction were approximated by a meta-model of optimal prognosis (MOP) and optimization was carried out using an evolutionary algorithm (EA). It was shown that the tribological behavior was mainly determined by the basic geometric pairing and the radii while eccentricity was of subordinate role. Furthermore, there was a trade-off between high load carrying capacity and low frictional losses. Thereby, spherical or toroidal geometries on the roller end face featuring a large radius paired with a tapered rib geometry were found to be advantageous in terms of low friction. For larger lubricant film heights and load carrying capacity, spherical or toroidal roller on toroidal rib geometries with medium radii were favorable.


2021 ◽  
Vol 157 ◽  
pp. 106876
Author(s):  
Justino A.O. Cruz ◽  
Pedro M.T. Marques ◽  
Jorge H.O. Seabra ◽  
Ramiro C. Martins

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1371 ◽  
Author(s):  
Francisco Brosed ◽  
A. Zaera ◽  
Emilio Padilla ◽  
Fernando Cebrián ◽  
Juan Aguilar

Tapered roller bearings can accommodate high radial loads as well as high axial loads. The manufacturing process consists of machining processes for ring and component assembly. In this contribution, the parameters of influence on the measurement procedure were studied. These parameters of influence were classified as environmental, process, and machine parameters. The main objective of this work was to optimize the process using real-time measurements, which required the study of the influence of several parameters on the measurement uncertainty and how to correct their effects.


2018 ◽  
Vol 3 (2) ◽  
pp. 947-960 ◽  
Author(s):  
Jonathan Keller ◽  
Yi Guo ◽  
Zhiwei Zhang ◽  
Doug Lucas

Abstract. In this paper, the planetary load-sharing behavior and fatigue life of different wind turbine gearboxes when subjected to rotor moments are examined. Two planetary bearing designs are compared – one design using cylindrical roller bearings with clearance and the other design using preloaded tapered roller bearings to support both the carrier and planet gears. Each design was developed and integrated into a 750 kW dynamometer tests, the loads on each planet bearing row were measured and compared to finite-element models. Bearing loads were not equally shared between the set of cylindrical roller bearings supporting the planets even in pure torque conditions, with one bearing supporting up to 46 % more load than expected. A significant improvement in planetary bearing load sharing was demonstrated in the gearbox with preloaded tapered roller bearings with maximum loads 20 % lower than the gearbox with cylindrical roller bearings. Bearing life was calculated with a representative duty cycle measured from field tests. The predicted fatigue life of the eight combined planet and carrier bearings for the gearbox with preloaded tapered roller bearings is 3.5 times greater than for the gearbox with cylindrical roller bearings. The influence of other factors, such as carrier and planet bearing clearance, gravity, and tangential pin position error, is also investigated. The combined effect of gravity and carrier bearing clearance was primarily responsible for unequal load sharing. Reducing carrier bearing clearance significantly improved load sharing, while reducing planet clearance did not. Normal tangential pin position error did not impact load sharing due to the floating sun design of this three-planet gearbox.


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