Influences of Additives on the Wear Protection of PVD-Coated and Ester Lubricated Roller Thrust Bearings

2005 ◽  
Author(s):  
P. W. Gold ◽  
J. Loos ◽  
M. Kuhn
Keyword(s):  
World Wide ◽  
Roller Bearing ◽  
Boundary Friction ◽  
Extreme Pressure ◽  
Pvd Coatings ◽  
Test Rig ◽  
Rolling Bearings ◽  
Thrust Bearings ◽  
Wear Protection ◽  
Cylindrical Roller

Mixed friction cannot always be avoided in rolling bearings. It is therefore necessary to protect the bearings against wear. Nowadays, extreme-pressure- and anti-wear-additives fulfill this function. As these additives are harmful to the environment it was systematically examined to what extent PVD-coatings are able to take over their function. The effectiveness of the coatings was tested in the FE8 lubricant roller bearing test rig on the basis of cylindrical roller thrust bearings. With the help of this world wide established test rig the roller bearings are tested on boundary friction conditions (κ ≪ 1).

scholarly journals Manufacturing and Evaluation of Multi-Material Axial-Bearing Washers by Tailored Forming

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 232 ◽  
Author(s):  
Bernd-Arno Behrens ◽  
Alexander Chugreev ◽  
Tim Matthias ◽  
Gerhard Poll ◽  
Florian Pape ◽  
...  
Keyword(s):  
Layer Structure ◽  
Roller Bearing ◽  
Welding Process ◽  
Rolling Contact ◽  
Acoustic Microscopy ◽  
Research Centre ◽  
Forming Process ◽  
Rolling Bearings ◽  
Cylindrical Roller ◽  
Tailored Forming

Components subject to rolling contact fatigue, such as gears and rolling bearings, are among the fundamental machine elements in mechanical and vehicle engineering. Rolling bearings are generally not designed to be fatigue-resistant, as the necessary oversizing is not technically and economically marketable. In order to improve the load-bearing capacity, resource efficiency and application possibilities of rolling bearings and other possible multi-material solid components, a new process chain was developed at Leibniz University Hannover as a part of the Collaborative Research Centre 1153 “Tailored Forming”. Semi-finished products, already joined before the forming process, are used here to allow a further optimisation of joint quality by forming and finishing. In this paper, a plasma-powder-deposition welding process is presented, which enables precise material deposition and control of the welding depth. For this study, bearing washers (serving as rolling bearing raceways) of a cylindrical roller thrust bearing, similar to type 81212 with a multi-layer structure, were manufactured. A previously non-weldable high-performance material, steel AISI 5140, was used as the cladding layer. Depending on the degree of forming, grain-refinement within the welded material was achieved by thermo-mechanical treatment of the joining zone during the forming process. This grain-refinements lead to an improvement of the mechanical properties and thus, to a higher lifetime for washers of an axial cylindrical roller bearing, which were examined as an exemplary component on a fatigue test bench. To evaluate the bearing washers, the results of the bearing tests were compared with industrial bearings and deposition welded axial-bearing washers without subsequent forming. In addition, the bearing washers were analysed micro-tribologically and by scanning acoustic microscopy both after welding and after the forming process. Nano-scratch tests were carried out on the bearing washers to analyse the layer properties. Together with the results of additional microscopic images of the surface and cross-sections, the causes of failure due to fatigue and wear were identified.

scholarly journals Influence of manufacturing errors of bearing components on rotational accuracy of cylindrical roller bearings

2021 ◽  
Author(s):  
Yongjian Yu ◽  
Jishun Li ◽  
Yujun Xue
Keyword(s):  
Coupling Effect ◽  
Roller Bearing ◽  
Contributing Factors ◽  
Rolling Bearings ◽  
Motion Error ◽  
Manufacturing Errors ◽  
Manufacturing Tolerances ◽  
Component Manufacturing ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Abstract Understanding the influence of bearing component manufacturing errors and roller number on the rotational accuracy of rolling bearings is crucial in the design of high precision bearings. The rotational accuracy of an assembled bearing is dependent upon roller number and manufacturing error of the bearing components. We propose a model for calculating the rotational accuracy of a cylindrical roller bearing; we experimentally verified the effectiveness of the model in predicting the radial run-out of the inner ring proposed in the previous paper in this series. We sought to define the key contributing factors to the rotational accuracy by studying both the influence of the coupling effect of the roller number and the influence of the manufacturing errors in the inner raceway, outer raceway, and rollers on the motion error. The model and results will help engineers choose reasonable manufacturing tolerances for bearing components to achieve the required rotational accuracy.

Influence of Groove Dimensions on the Tribological Behavior of Textured Cylindrical Roller Thrust Bearings under Starved Lubrication

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Risheng Long ◽  
Chao Zhao ◽  
Zhihao Jin ◽  
Yimin Zhang ◽  
Zhen Pan ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Tribological Behavior ◽  
Roller Bearing ◽  
Wear Loss ◽  
Wear Properties ◽  
Content Type ◽  
Thrust Bearings ◽  
Surface Stresses ◽  
Starved Lubrication ◽  
Cylindrical Roller

Purpose The purpose of this paper is to reveal the friction and wear performance of grooves textured cylindrical roller thrust bearings with different groove dimensions under starved lubrication. Design/methodology/approach The groove dimensions include: width of grooves (WOG, 50 µm, 100 µm and 150 µm), depth of grooves (DPOG, 7 µm, 11 µm and 15 µm) as well as groove deflection angle (GDA, 45°). A fiber laser marking system was used to prepare groove patterns on the raceways of shaft washers. The friction and wear properties of grooves textured bearings were researched through a vertical universal wear test rig using a customized roller bearing tribo-pair under starved lubrication. Static finite element analyses were conducted to reveal their surface stresses. Through the comprehensive comparison and analyses, the influence mechanism of grooves on the tribological behavior of cylindrical roller thrust bearings was proposed and discussed. Findings When grooves textured bearings run under starved lubrication, their average coefficients of friction (COFs) and wear losses are all significantly reduced and much lower than those of smooth group. The influence of DPOG on the COF curves is significant, while the influence of WOG on the COF curves is a little weak. The influence of groove dimensions on the surface stresses of grooves textured bearings is weak, whether the WOG or DPOG. In this work, when the WOG is 100 µm and the DPOG is 15 µm, its average COF and wear loss are both the lowest, 0.0066 and 0.61 mg, respectively. Compared with the data of smooth group, its friction coefficient is reduced by 75.3% and its mass loss is reduced by 95.8%, showing a significant improvement in this condition. Originality/value This work can provide a valuable reference for the raceway design and reliability optimization of rolling element bearings.

scholarly journals Post-testing measurement of freely movable and diffusible hydrogen in context of WEC formation at cylindrical roller thrust bearings from 100Cr6

Friction ◽  
2020 ◽  
Author(s):  
Martin Linzmayer ◽  
Francisco Gutiérrez Guzmán ◽  
Gregor Manke ◽  
Georg Jacobs ◽  
Christopher Sous ◽  
...  
Keyword(s):  
Hydrogen Content ◽  
Atomic Hydrogen ◽  
Test Rig ◽  
Diffusible Hydrogen ◽  
Comparative Tests ◽  
Thrust Bearings ◽  
Bearing Failures ◽  
Type Test ◽  
Hydrogen Analysis ◽  
Cylindrical Roller

AbstractSub-surface crack networks in areas of altered microstructure are a common cause for bearing failures. Due to its appearance under light microscopy, the damage pattern is referred to as White Etching Cracks (WEC). The root causes leading to the formation of WEC are still under debate. Nevertheless, it has already been shown that atomic hydrogen can have an accelerating effect on the formation and propagation of WEC. In addition to hydrogen pre-charging, hydrogen can be released and absorbed during rolling/sliding due to the decomposing of the lubricant and water. The current work focuses on the analysis of the hydrogen content of cylindrical roller thrust bearings after testing in a FE8 type test rig using two different lubricants. Within the framework of this work, two different hydrogen analysis methods were used and assessed regarding their applicability. The results show that the so-called Hydrogen Collecting Analysis (HCA) is more suitable to investigate the correlation between lubricant chemistry and hydrogen content in the test bearings than the Local Hydrogen Analysis (LHA). The measurements with the HCA show a continuously increasing freely movable and diffusible hydrogen content under tribological conditions, which leads to the formation of WEC. Comparative tests with an oil without hydrogen showed that the tendency of the system to fail as a result of WEC can be reduced by using a lubricant without hydride compounds.

scholarly journals Dynamic Performance of a Squeeze Film Damper with a Cylindrical Roller Bearing under a Large Static Radial Loading Range

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 14 ◽  
Author(s):  
Hans Meeus ◽  
Jakob Fiszer ◽  
Gabriël Van De Velde ◽  
Björn Verrelst ◽  
Wim Desmet ◽  
...  
Keyword(s):  
Roller Bearing ◽  
Squeeze Film ◽  
Stable Operation ◽  
Large Power ◽  
Squeeze Film Damper ◽  
Depth Analysis ◽  
Rotor Support ◽  
Cylindrical Roller Bearing ◽  
Radial Loading ◽  
Cylindrical Roller

Turbomachine rotors, supported by little damped rolling element bearings, are generally sensitive to unbalance excitation. Accordingly, most machines incorporate squeeze film damper technology to dissipate mechanical energy caused by rotor vibrations and to ensure stable operation. When developing a novel geared turbomachine able to cover a large power range, a uniform mechanical drivetrain needs to perform well over the large operational loading range. Especially, the rotor support, containing a squeeze film damper and cylindrical roller bearing in series, is of vital importance in this respect. Thus, the direct objective of this research project was to map the performance of the envisioned rotor support by estimating the damping ratio based on the simulated and measured vibration response during run-up. An academic test rig was developed to provide an in-depth analysis on the key components in a more controlled setting. Both the numerical simulation and measurement results exposed severe vibration problems for an insufficiently radial loaded bearing due to a pronounced anisotropic bearing stiffness. As a result, a split first whirl mode arose with its backward component heavily triggered by the synchronous unbalance excitation. Hence, the proposed SFD does not function properly in the lower radial loading range. Increasing the static load on the bearing or providing a modified rotor support for the lower power variants will help mitigating the vibration issues.

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