A study on the effect of acceleration on slip velocity and lubrication performance in cylindrical roller bearings

2016 ◽  
Vol 230 (10) ◽  
pp. 1231-1243 ◽  
Author(s):  
Wei Cao ◽  
Jiaxu Wang ◽  
Wei Pu ◽  
Ying Zhang ◽  
Jiqiang Wu ◽  
...  
Keyword(s):  
Slip Velocity ◽  
Roller Bearings ◽  
Lubrication Performance ◽  
Cylindrical Roller

Film Thickness, Friction, and Scuffing Failure of Rib/Roller End Contacts in Cylindrical Roller Bearings

1992 ◽  
Vol 114 (2) ◽  
pp. 311-316 ◽  
Author(s):  
H. Aramaki ◽  
H. S. Cheng ◽  
D. Zhu
Keyword(s):  
Film Thickness ◽  
Critical Load ◽  
Strongly Correlated ◽  
Wear Process ◽  
Load Dependence ◽  
Roller Bearings ◽  
High Speeds ◽  
Lubrication Performance ◽  
Minimum Film Thickness ◽  
Cylindrical Roller

The lubrication performance of rib/roller end contacts of cylindrical roller bearings was studied both theoretically and experimentally for end-crowned rollers and inclined ribs. A partial EHL program was used to calculate the film thickness and the friction in the rib/roller end contact. Calculated minimum film thickness shows a strong load dependence although the central film thickness is still a weak function of the load. The influence of the contact position on the film thickness was also investigated for roller skewness and design tolerance. It was found that the contact location affects the minimum film thickness strongly in spite of a weak influence on the central film thickness. Friction and scuffing experiments were conducted on a special rig, which can achieve arbitrary slide/roll ratio to simulate the rib/roller end contacts. Good agreements were found between measured and calculated friction based on the assumption that the lubricant was Newtonian. In scuffing experiments, scuffing propagation was observed on the rib contact surface. The critical load for scuffing is strongly correlated with the sliding velocity. The critical load at high speeds is lower than that at low speeds although the friction at high speeds is lower. These data imply the importance of the contact location and the wear process for film breakdown.

Theoretische Analyse eines neuen Loslagerkonzepts*/Theoretical analysis of a new floating bearing - The simulated operational behavior of FRB bearings in comparison to reference bearings

2015 ◽  
Vol 105 (05) ◽  
pp. 285-290
Author(s):  
C. Brecher ◽  
M. Fey ◽  
J. Falker
Keyword(s):  
Experimental Investigation ◽  
Theoretical Analysis ◽  
High Speed ◽  
Contact Point ◽  
Ball Bearings ◽  
Roller Bearings ◽  
Cylindrical Roller ◽  
Bearing System

Das Floating-Roller-Ball (FRB)-Lager ist ein Konzept für Radiallager als Loslager für Hochgeschwindigkeits-Motorspindeln, das die Vorteile von Zylinderrollenlagern und angestellten Mehrpunktlagern in einer neuen Wälzkörpergeometrie kombiniert. Zur Auslegung des ersten Prototyps wurde mithilfe eines Berechnungstools das theoretische Betriebsverhalten untersucht. Die Berechnungsergebnisse liefern Randbedingungen als Grundlage zur experimentellen Untersuchung des Lagerkonzepts.   Floating roller ball bearings provide a new floating bearing system for high-speed motor spindles, combining the advantages of both cylindrical roller bearings and elastically mounted multi-contact point bearings in a new roller geometry. To design the first prototype, the operational behavior of the bearing system was analyzed theoretically by a new calculation tool. The results provide the basis for the experimental investigation of the bearing concept.

Some Effects of Lubricant Starvation in Cylindrical Roller Bearings

1976 ◽  
Vol 98 (1) ◽  
pp. 66-71 ◽  
Author(s):  
R. A. Hargreaves ◽  
G. R. Higginson
Keyword(s):  
Friction Torque ◽  
Roller Bearings ◽  
Oil Mist ◽  
Operating Temperatures ◽  
Cylindrical Roller

Experiments on cylindrical roller bearings of 50-mm bore lubricated by an air/oil mist show that friction torque and operating temperatures are much reduced by running at low lubricant supply rates.

scholarly journals Comparison of planetary bearing load-sharing characteristics in wind turbine gearboxes

2018 ◽  
Vol 3 (2) ◽  
pp. 947-960 ◽  
Author(s):  
Jonathan Keller ◽  
Yi Guo ◽  
Zhiwei Zhang ◽  
Doug Lucas
Keyword(s):  
Fatigue Life ◽  
Wind Turbine ◽  
Load Sharing ◽  
Position Error ◽  
Bearing Clearance ◽  
Roller Bearings ◽  
Bearing Load ◽  
Tapered Roller ◽  
Tapered Roller Bearings ◽  
Cylindrical Roller

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.

An Optimum Design of Crowned Cylindrical Roller Bearings Using Genetic Algorithms

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
K. Sunil Kumar ◽  
Rajiv Tiwari ◽  
P. V. V. N. Prasad
Keyword(s):  
Genetic Algorithms ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Stress Concentrations ◽  
Rolling Bearings ◽  
Design Constraint ◽  
Roller Bearings ◽  
Edge Stress ◽  
Heavy Loads ◽  
Cylindrical Roller

The long fatigue life is the one of the most important criterion for the design of rolling bearings, however, due to complex and diverse internal geometries, each type of rolling bearings require a different design formulation. To increase the life of cylindrical roller bearings, the profile (or the crowning) of the roller plays an important role. A flat profile of the rolling element results in the edge stress concentrations at roller ends. A circular crowning of roller eliminates the edge stress concentration at the lower and moderate loads only; however, it develops edge stress concentrations at heavy loads. The logarithmic profile of the roller results in no edge stress concentration at the low, medium, and heavy loads; distribution of contact stresses is also nearly uniform along the length of the roller. A design methodology for the optimum design of cylindrical roller bearings with the logarithmic profile has been outlined. A nonlinear constrained optimization problem has been formulated for the design of cylindrical roller bearings with logarithmic profiles and is optimized by using real-coded genetic algorithms. The change in roller profile has not been accounted for explicitly in the standard definition of the dynamic capacity; hence, for the present case directly the Lundberg–Palmgren life equation has been chosen as an objective function. Design variables include four bearing geometrical parameters and the two logarithmic profile generating parameters are considered. In addition to these, another five design constraint constants are also included, which indirectly affect the fatigue life of cylindrical roller bearings. The five design constraint constants have been given bounds based on the parametric studies through initial optimization runs. The effective length of the roller is taken corresponding to the standard roller diameter, which has standard discrete dimensions. Constraint violation study has been performed to have an assessment of the effectiveness of each of the constraints. A convergence study has been carried out to ensure the global optimum point in the design. A sensitivity analysis of various geometric design parameters has been performed using the Monte Carlo simulation technique, in order to see changes in the fatigue life of the bearing. Illustrations show that the multiplier of the logarithmic profile deviation parameter has more effect on the fatigue life as compared with other geometric parameters.

scholarly journals Prevention of Smearing Damage in Cylindrical Roller Bearings

2013 ◽  
Vol 56 (5) ◽  
pp. 703-716 ◽  
Author(s):  
Ryan D. Evans ◽  
Todd A. Barr ◽  
Luc Houpert ◽  
Steven V. Boyd
Keyword(s):  
Roller Bearings ◽  
Cylindrical Roller
Sign in / Sign up

Export Citation Format

Share Document