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1
Li, Song Sheng, Zhi Hong Hu, Peng Zhou, Peng Chen, Xiao Yang Chen, Jia Ming Gu und Li Xia Fu. „Analysis of Heating Performances for Ultra-High Speed Electric Spindle Bearings Based on the Energy Theory of TEHL in Point Contact State“. Applied Mechanics and Materials 37-38 (November 2010): 135–40. http://dx.doi.org/10.4028/www.scientific.net/amm.37-38.135.
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To analyze the lubricating state and the heating performances of the spindle bearings in ultra-high speed electric spindles, taken the characteristics of oil-air lubrication into account and based on the theories about rolling bearing dynamics and thermal elasto-hydrodynamic lubrication in point contact state, a model was built with the energy method for analyzing the heating performances the ball elements on both raceways in spindle bearings. An equation was derived for calculating the total quality of heat produced in a bearing. The influences of some basic factors such as the running speed, the axial preload, the oil viscidity, the design contact angle of bearing, and the ball materials and so on are analyzed on the heating performances in a bearing. The results show that it is easy to come into being elasto-hydrodynamic lubrication state for a bearing running in an ultra high-speed and lubricated by oil-air. It is also shown that the higher speed is, the more the quality of heat produced inside the oil films in the elasto-hydrodynamic lubrication state will be, which will bring the bearings working conditions worse.
2
Bao, Heyun, Xiaonan Hou, Xin Tang und Fengxia Lu. „Analysis of temperature field and convection heat transfer of oil-air two-phase flow for ball bearing with under-race lubrication“. Industrial Lubrication and Tribology 73, Nr. 5 (13.07.2021): 817–21. http://dx.doi.org/10.1108/ilt-03-2021-0067.
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Purpose Under-race lubrication can increase the amount of lubricating oil entering a bearing and greatly improve lubrication and cooling effects. The oil-air two-phase flow and heat transfer characteristics inside a ball bearing with under-race lubrication play a key role in lubrication and cooling performance. The purpose of this paper is to study these two characteristics, and then provide guidance for lubrication and heat dissipation of bearing with under-race lubrication. Design/methodology/approach In this paper, a simplified three-dimension heat transfer model of ball bearing with under-race lubrication is established; the coupled level set volume of fluid method is used to track the oil-air two-phase flow, and the Palmgren method is used to calculate the heat generation. The influence of rotation speed and inlet velocity on oil volume fraction, temperature and convection heat transfer is investigated. A temperature test for under-race lubrication is carried out. Findings Because of the centrifugal force, lubricating oil is located more on the outer ring raceway. As the rotation speed decreases and the inlet velocity increases, the oil volume fraction increases and the temperature decreases. Furthermore, the area with high oil volume fraction has a large convection heat transfer coefficient and low temperature. The error between the simulation temperature and the test temperature is within 10%. Originality/value The research on the temperature field and convection heat transfer characteristics of under-race lubrication ball bearings at different rotation speeds and inlet velocities is rarely involved.
3
Sun, Jun, Xinlong Zhu, Liang Zhang, Xianyi Wang, Chunmei Wang, Hu Wang und Xiaoyong Zhao. „Effect of surface roughness, viscosity-pressure relationship and elastic deformation on lubrication performance of misaligned journal bearings“. Industrial Lubrication and Tribology 66, Nr. 3 (08.04.2014): 337–45. http://dx.doi.org/10.1108/ilt-12-2011-0110.
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Purpose – Current lubrication analyses of misaligned journal bearings were generally performed under some given preconditions. To make the lubrication analysis closer to the actual situation and usable to the journal bearing design, the purpose of this paper was to calculate the lubrication characteristics of misaligned journal bearings considering the viscosity-pressure effect of the oil, the surface roughness and the elastic deformation of the journal bearing at the same time. Design/methodology/approach – The lubrication of bearings was analyzed using the average Reynolds equation. The deformation of the bearing surface under oil film pressure was calculated by a compliance matrix method. The compliance matrix was established by finite element analysis of the bearing housing. The viscosity-pressure and viscosity–temperature equations were used in the analysis. Findings – The oil viscosity-pressure relationship has a significant effect on the lubrication of misaligned journal bearings. The surface roughness will affect the lubrication of misaligned journal bearings when the eccentricity ratio and angle of journal misalignment are all large. The directional parameter of the surface has an obvious effect on the lubrication of misaligned journal bearings. The deformation of the bearing surface has a remarkable effect on the lubrication of misaligned journal bearings. Originality/value – The lubrication characteristics of misaligned journal bearings were calculated considering the viscosity-pressure effect of the oil, the surface roughness and the elastic deformation of the journal bearing at the same time. The results of this paper are helpful to the design of the bearing.
4
Kingsbury, E. „Parched Elastohydrodynamic Lubrication“. Journal of Tribology 107, Nr. 2 (01.04.1985): 229–32. http://dx.doi.org/10.1115/1.3261026.
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A parched subregime of elastohydrodynamic lubrication is proposed, lying between starved and mixed. Parched EHL is necessary to describe instrument ball bearing behavior, for example: long term transients in film thickness. A parched bearing has the least driving torque demand and best spin axis definition possible from any lubrication regime. Some measurements made in a 40 mm bore bearing show that parched operation is not limited to small bearings.
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CZABAN, Adam. „CFD ANALYSIS OF THE HYDRODYNAMIC LUBRICATION OF A MISALIGNED, SLIDE CONICAL BEARING“. Tribologia 268, Nr. 4 (31.08.2016): 41–53. http://dx.doi.org/10.5604/01.3001.0010.6977.
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The lateral loads carried by hydrodynamic bearings, and also their uneven distribution, introduce an additional axial misalignment between the shaft and sleeve. The machining and mounting errors also result in improper initial alignment of bearing shaft or sleeve. Furthermore, due to vibrations, misalignment of shaft fluctuates during the operation of the bearing. This has an impact on the operating parameters of the bearing, and, in extreme cases, where the maximum allowable value of the misalignment is exceeded, the bearing can be damaged. The aim of this work is to investigate the effect of misalignment on the hydrodynamic pressure distribution in the conical sliding bearing lubrication gap and on the bearing load carrying capacity and friction force values. This paper shows the result of a CFD simulation of hydrodynamic conical bearings lubrication with the assumption that the bearings are misaligned, i.e. where the rotation axis of bearing shaft is not parallel to the axis of the cone of the bearing sleeve. The commercial CFD software ANSYS Fluent was used in this research. It was assumed that the flow of lubricating oil is laminar, without slipping on bearing surfaces, and that the oil has non-Newtonian properties.
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Pratama, Edward Rangga, und Alaya Fadllu Hadi Mukhammad. „Bearing Failure Analysis on Gearbox Forced Draft Fan at LNG Plant“. Indonesian Journal of Science and Technology 3, Nr. 2 (30.08.2018): 124. http://dx.doi.org/10.17509/ijost.v3i2.12756.
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Boilers Forced Draft Fan has a gearbox reducer to reduce speed from steam turbine as a driver and fan as the driven. Based on Predictive Maintenance Group at Machinery and Heavy Equipment Section, it was found that gearbox has high vibration and noise when boilers load on 195 Ton/Hr (Max Load 295 Ton/hr). Vibration Analysis indicates that the source of vibration comes from bearings with peak value 0.572 in/sec at gearbox high speed outboard vertical and 0.593 in/sec at gearbox high speed outboard horizontal (Max Allowance 0.50 in/sec). Lubrication analysis using X-ray Flourescence method, to see wear particle on lubricating oil showed that Tin(Sn) content is very high 203.62 mg/L (maximum allowance for Tin(Sn) at gearbox is 20mg/L), but wear debris are not found in lubricating oil. Gearbox disassembly found that high speed and low speed bearings suffered severe corrosion. Corrosion at bearings are caused by water contamination on lubrication oil, it comes from steam leak due to carbon ring failure at steam turbine which is steam turbine bearing lubrication and gearbox lubrication get into one lubrication system. After Bearings replaced with a new one, vibration analysis shown improved vibration conditions 0.084 in/sec at gearbox high speed outboard vertical and 0.066 in/sec at gearbox high speed outboard horizontal. In conclucion, high vibration and noise at gearbox reducer were caused by bearings failure due to severe corrosion, and water contamination on lubrication oil for gearbox due to carbon ring failure on steam turbine.
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Jin, Z. M., D. Dowson und J. Fisher. „Analysis of fluid film lubrication in artificial hip joint replacements with surfaces of high elastic modulus“. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 211, Nr. 3 (01.03.1997): 247–56. http://dx.doi.org/10.1243/0954411971534359.
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Lubrication mechanisms and contact mechanics have been analysed for total hip joint replacements made from hard bearing surfaces such as metal-on-metal and ceramic-on-ceramic. A similar analysis for ultra-high molecular weight polyethylene (UHMWPE) against a hard bearing surface has also been carried out and used as a reference. The most important factor influencing the predicted lubricating film thickness has been found to be the radial clearance between the ball and the socket. Full fluid film lubrication may be achieved in these hard/hard bearings provided that the surface finish of the bearing surface and the radial clearance are chosen correctly and maintained. Furthermore, there is a close relation between the predicted contact half width and the predicted lubricating film thickness. Therefore, it is important to analyse the contact mechanics in artificial hip joint replacements. Practical considerations of manufacturing these bearing surfaces have also been discussed.
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Qiu, Jun Peng, Mei Yin und Ling Song Guo. „Lubrication Mode and Selection of the Helicopter Transmission System Roller Bearing“. Applied Mechanics and Materials 86 (August 2011): 156–61. http://dx.doi.org/10.4028/www.scientific.net/amm.86.156.
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The bearings will directly affect the performance of helicopter transmission system whether they are in normal work or not. Lubrication is the essential element for the normal work of bearings. Under the condition of the bearing design and manufacture technique, material technique is becoming more and more advanced, and lubricant becomes “the fifth main part”, which has been got a wide-ranged agreement. One of the most critical factors to improve bearing life is lubricant. This paper analyzes lubrication type and mode, and the failure of helicopter transmission system roller bearing caused by improper lubrication. It further explains the importance of lubrication to the bearings. And how to select lubrication mode and lubricant to improve the bearing life is also summed up.
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Sun, Pei Ming, Xie Ben Wei und Shu Qin Chen. „The Research of Lubricating and Colling System of the Low-Speed and Heavy-Load Sliding Bearing“. Advanced Materials Research 744 (August 2013): 95–99. http://dx.doi.org/10.4028/www.scientific.net/amr.744.95.
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This paper analyzes the influence of lubricating oil film of the low-speed and heavy-load sliding bearing on a variety of factors. It introduces the operation of Bearing for lubricating oil film in monitoring method, common fault causes and treatment measures. Finally, the bearing cooling system structure is discussed, providing reference for practical engineering application. There are many reasons to cause the failure of the bearing lubrication such as bearing assembly defects, the error of size and cooling system problems. By detecting and contrast parameters, this study analyze the determine data and correct the fault. Through the use of reasonable structure of the oil tank and cooling water channel, we can improve the lubrication performance, and extend the bearing life. This paper analyzes the factors restricting the low speed and high load sliding bearing lubricant film, and solves the actual bearing lubrication problem.
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Zhang, Feng, Gong Bo Han und Su Xia Duan. „Paper Machine Bearing’s Temperature and Air-Velocity Optimization under Air-Oil Lubrication“. Advanced Materials Research 550-553 (Juli 2012): 3054–58. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.3054.
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The purpose of this resarch was investigated the air-oil temperature field distribution under air-oil lubrication and oil lublubrication, meanwhile also study the air-oil lubrication effect under different air velocity inlet the bearing cavities of the high-speed paper machine dryer section. Base on the CFD theory, the temperature field of CARB bearing outer ring and the velocity field of the bearing cavities were simulated by the FLUENT software.Result show that air-oil lubricatin can reach the same cooling effect is contras with oil lubrication in the same heat production by roller; the best air-velocity value of air-oil lubrication system is obtain for the change of temperature and pressure in bearing cavities. It is confirm that the air-oil lubrication is viable in the high-speed paper machine dryer section.
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Santos, Ilmar Ferreira, und Fla´vio Yukio Watanabe. „Compensation of Cross-Coupling Stiffness and Increase of Direct Damping in Multirecess Journal Bearings Using Active Hybrid Lubrication: Part I—Theory“. Journal of Tribology 126, Nr. 1 (01.01.2004): 146–55. http://dx.doi.org/10.1115/1.1631015.
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Fluid film forces are generated in hydrostatic journal bearings by two types of lubrication mechanisms: the hydrostatic lubrication in the bearing recesses and hydrodynamic lubrication in the bearing lands, when operating in rotation. The combination of both lubrication mechanisms leads to hybrid journal bearings (HJB). When part of hydrostatic pressure is also dynamically modified by means of hydraulic control systems, one refers to the active lubrication. The main contribution of the present theoretical work is to show that it is possible to reduce cross-coupling stiffness and increase the direct damping coefficients by means of the active lubrication, what leads to rotor-bearing systems with larger threshold of stability.
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Sikorski, Jakub, und Witold Pawlowski. „Internal Friction of Ball Bearings at Very Low Temperatures“. Strojniški vestnik – Journal of Mechanical Engineering 66, Nr. 4 (15.04.2020): 235–42. http://dx.doi.org/10.5545/sv-jme.2019.6398.
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Results of the study on the internal friction of steel ball bearings made of X65Cr14 alloy and ceramic bearings made of zirconium oxide operating at temperatures lowered by liquid nitrogen down to –195 °C are presented in this paper. Standard grease added by the manufacturer, while graphite and molybdenum disulphide powder were used for lubrication of the bearings during the measurements. Tests were also carried out to examine the performance of the bearings operating without lubrication. The power of bearing internal friction versus temperature was measured. The lowest bearing internal friction was observed for molybdenum disulphide, whose effective lubricating performance was verified for both types of ball bearings. Graphite powder was almost equally effective with the advantage of being suitable for use in machines that come into contact with food.
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Raykovskiy, N. A., V. L. Yusha, A. V. Tretyakov und V. A. Zakharov. „Theoretical Estimation of Thermal Deformations of Non-Lubricated Bearings of Low-Flow Turbocharger Units“. Proceedings of Higher Educational Institutions. Маchine Building, Nr. 10 (715) (Oktober 2019): 58–69. http://dx.doi.org/10.18698/0536-1044-2019-10-58-69.
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When designing turbocharger units (microturbines) working with high-temperature flows, it is possible to completely abandon lubrication system and use self-lubricating bearings instead. At the same time, it is important to ensure the required temperature regimes and permissible temperature deformations. Currently, there are no calculation methods that could be used to determine the temperature fields and temperature deformations of the ‘rotor — self-lubrication bearings’ system. The paper proposes a numerical method for calculating bearing assemblies, which takes into account the mutual influence of the operating modes of the turbine unit and the bearing cooling system. The proposed method is tested, and the results of the analysis of temperatures and temperature deformations are presented.
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Zhao, Xiu Xu, An Jian Huang und Zhi Xiang Hu. „Numerical Analysis of High Power Marine Diesel Engine Main Bearing Load and Lubricating Properties“. Applied Mechanics and Materials 331 (Juli 2013): 25–30. http://dx.doi.org/10.4028/www.scientific.net/amm.331.25.
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The main bearing is one of the primary friction pairs of a diesel engine. The lubrication condition affects the performance of the marine diesel engine directly. Continuous working time of main bearings is longer, load is higher and working condition is even worse especially in low medium speed marine diesel engine, making it difficult to form good dynamic pressure lubrication.Therefore, this paper takes a high-power marine diesel G32 with 9 cylinders as an example, calculates and analyzes the load, the orbit of main shaft center and the minimum thickness of oil film in each main bearing, providing the basis to estimate each main bearing’s lubricating condition, predicting each main bearing’s performance precisely and judging whether there exists abnormal working conditions in each main bearing.
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Lu, Fengxia, Meng Wang, Wenbin Pan, Heyun Bao und Wenchang Ge. „CFD-Based Investigation of Lubrication and Temperature Characteristics of an Intermediate Gearbox with Splash Lubrication“. Applied Sciences 11, Nr. 1 (31.12.2020): 352. http://dx.doi.org/10.3390/app11010352.
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In this study, we propose a computational fluid dynamics (CFD)-based method to study the lubrication and temperature characteristics of an intermediate gearbox with splash lubrication. A volume of fluid (VOF) multiphase model was used to track the interface between oil and air. A multiple reference frame (MRF) model was adopted to accurately simulate the movement characteristics of the gears, bearings, and the surrounding flow field. The thermal-fluid coupling computational model of an intermediate gearbox with splash lubrication was then established. Combined with experimental results, we verified that the lubricating oil temperature was below the limit requirement (<110 °C). The numerical results revealed that large amounts of lubricating oil were splashed onto the tooth surfaces near the gear meshing area. A large convective heat transfer coefficient corresponds to a low gear tooth surface temperature. The tooth surface temperature of the driving gear is higher than that of the driven gear. The distribution law of oil volume fraction of the bearing roller was jointly affected by the roller rotation direction and gravity. The convective heat transfer coefficient of the roller wall was largely related to the lubrication environment of the roller, including the oil distribution inside the bearing cavity and the flow rate.
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Jones, E., S. C. Scholes, A. Unsworth und I. C. Burgess. „Compliant-layer tibial bearing inserts: Friction testing of different materials and designs for a new generation of prostheses that mimic the natural joint“. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 222, Nr. 8 (01.11.2008): 1197–208. http://dx.doi.org/10.1243/09544119jeim442.
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Total joint replacements (TJRs) have a limited lifetime, but the introduction of devices that exhibit good lubricating properties with low friction and low wear could well extend this. A novel tibial bearing design, using polyurethane (PU) as a compliant layer, to mimic the natural joint, has been developed. To determine accurately the mode of lubrication under which these joints operate, a synthetic lubricant was used in all these tests. Friction tests were carried out to assess the effects of material modulus and surface roughness, together with bearing design parameters such as bearing thickness and conformity, on lubrication. Corethane 80A was the preferred material and was chosen as the compliant layer for subsequent testing. A low surface roughness resulted in lower asperity contact as the asperities were depressed by the pressurized entraining fluid and full-fluid-film lubrication was approached. The three different tibial bearing conformities (low, medium, and high) did not appear to influence the mode of lubrication and all these bearings performed with extremely low friction. Similarly, the bearing thickness effects on lubrication at the levels tested (2 mm, 3 mm, and 4 mm) were minimal, although the effects of layer thickness on interface shear stress could be expected to be significant. This study describes a series of friction tests that have been used to select the most appropriate material and to optimize the design parameters to establish optimum conditions for these compliant layer joints.
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Bao, Heyun, Xiaonan Hou und Fengxia Lu. „Analysis of Oil-Air Two-Phase Flow Characteristics inside a Ball Bearing with Under-Race Lubrication“. Processes 8, Nr. 10 (01.10.2020): 1223. http://dx.doi.org/10.3390/pr8101223.
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Under-race lubrication can increase the amount of lubricating oil entering a bearing and greatly improve lubrication and cooling effects. The oil-air two-phase flow characteristics inside a ball bearing with under-race lubrication play a key role in lubrication and cooling performance. The motions of ball bearing subassemblies are complicated. Ball spin affects the oil volume fraction. In this paper, the coupled level set volume of fluid (CLSVOF) method is used to track the oil-air two-phase flow inside the ball bearing with under-race lubrication. The influence of various factors on the oil volume fraction inside the ball bearing with under-race lubrication is investigated, particularly rotating speeds, inlet velocity and the size of oil supply apertures under the inner ring. The influence of the ball spinning is analyzed separately. The result demonstrates that, on account of the centrifugal force, lubricating oil is located more on the outer ring raceway at rotational speeds of 5000 r/min, 10,000 r/min, 15,000 r/min and 20,000 r/min. The oil volume fraction inside the bearing gradually increases at an oil inlet velocity of 5 m/s, 10 m/s and 15 m/s. The circumferential distribution of oil is also similar. As the diameter of the oil supply aperture increases from 1.5 mm to 2 mm, the oil volume fraction increases inside the ball bearing. However, the oil volume fraction slightly decreases from 2 mm to 2.5 mm of oil supply aperture diameter. Ball spin does not affect the circumferential distribution trend of the lubricating oil, but slightly reduces the oil volume fraction. Furthermore, ball spin causes the surface fluid to rotate around its rotation axis and increases the speed.
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Xiang, Guo, Yanfeng Han, Renxiang Chen, Jiaxu Wang, Xiaokang Ni und Ke Xiao. „A hydrodynamic lubrication model and comparative analysis for coupled microgroove journal-thrust bearings lubricated with water“. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, Nr. 11 (06.11.2019): 1755–70. http://dx.doi.org/10.1177/1350650119884798.
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The novelty of this study is to develop a hydrodynamic lubrication numerical model for coupled microgroove journal-thrust bearings (or coupled bearings) under water-lubricated condition. In the present model, the continuity of the hydrodynamic pressure and the fluid field (or coupled hydrodynamic effect) at common boundary is considered to reveal the mutual effect between the hydrodynamic behavior of the journal bearing and the thrust bearing. The lubrication performances of the coupled microgroove bearing with three bottom shapes, i.e., isosceles triangle, right triangle, and left triangle, are studied comparatively. Additionally, the effects of the microgroove depth on the lubrication performances of the coupled bearing are discussed. The present study reveals that the coupled hydrodynamic effect generated by the coupled bearing can improve the lubrication performance for both the journal and the thrust bearing. The microgroove with left triangle bottom shape yields the optimal lubrication performance as compared to the other two. There is an optimal groove depth that generates the maximum load capacity and the minimum friction coefficient for both the journal and the thrust bearing.
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Guo Xiang, Guo Xiang, Yanfeng Han, Renxiang Chen, Jiaxu Wang Jiaxu Wang und Ni Xiaokang. „A numerical method to investigate the mixed lubrication performances of journal-thrust coupled bearings“. Industrial Lubrication and Tribology 71, Nr. 9 (04.11.2019): 1099–107. http://dx.doi.org/10.1108/ilt-02-2019-0063.
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Purpose This paper aims to present a numerical model to investigate the mixed lubrication performances of journal-thrust coupled bearings (or coupled bearings). Design/methodology/approach The coupled hydrodynamic effect (or coupled effect) between the journal and the thrust bearing is considered by ensuring the continuity of the hydrodynamic pressure and the flow field at the common boundary. The mixed lubrication performances of the coupled bearing are comparatively studied for the cases of considering and not considering coupled effect. Findings The simulated results show that the hydrodynamic pressure distributions for both the journal and thrust bearing are modified due to the coupled effect. The decreased load capacity of the journal bearing and the increased load capacity of the thrust bearing can be observed when the coupled effect is considered. And the coupled effect can facilitate in reducing the asperity contact load for both the journal and thrust bearing. Additionally, the interaction between the mixed lubrication behaviors, especially for the friction coefficient, of the journal and the thrust bearing is significant in the elastohydrodynamic lubrication regime, while it becomes weak in the mixed lubrication regime. Originality/value The developed model can reveal the mutual effects of the mixed lubrication behavior between the journal and the thrust bearing.
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Wang, Yingjia, Minshan Liu, Dongchen Qin und Zhenwei Yan. „Performance of high-speed hydrodynamic sliding bearings with lubricating oils combining laminar and turbulent flows“. Advances in Mechanical Engineering 12, Nr. 6 (Juni 2020): 168781402093338. http://dx.doi.org/10.1177/1687814020933389.
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High-speed hydrodynamic sliding bearings use lubricating oil that can have laminar and turbulent flow states, yet turbulent states remain relatively unstudied. This study combines theoretical analysis, numerical modeling, and experiments to analyze lubrication fluids in such bearings. It considers Reynolds equations, energy equations, and temperature-viscosity relationships under laminar and turbulent flows. The governing equations are solved by the finite difference method. Two-dimensional distributions of Reynolds number, pressure, and temperature in the bearing film, as well as the lubrication characteristics like bearing capacity and frictional force under working conditions, are analyzed. Single and mixed flow states are compared, which demonstrates the coexistence states of laminar and turbulent flows in an oil film under specific working conditions. Oil film flow distributions differ significantly according to rotational speed and eccentric conditions. Flow changes under high eccentricity are complex. The characteristics of oil films in a single flow state deviate significantly from those in mixed flow. Changes in flow state and heat should not be ignored during analysis of the lubrication performance of high-speed bearings.
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Zhang, Xiu Li, Zhong Wei Yin, Dan Jiang und Geng Yuan Gao. „Comparison of the Lubrication Performances of Water-Lubricated and Oil-Lubricated Plain Journal Bearings“. Applied Mechanics and Materials 711 (Dezember 2014): 27–30. http://dx.doi.org/10.4028/www.scientific.net/amm.711.27.
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Water-lubricated bearings have attracted increasing attention in recent years because of their environmental sustainability, simplified design, low cost, good cooling performance and low coefficient of friction. To show the characteristic of water lubrication more clearly, this paper quantitatively compares the lubrication performances of water-lubrication plain journal bearing and oil-lubricated plain journal bearing using CFD method. Bearing length, friction coefficients, power losses and temperature rises are obtained under the same working condition. Results show that water-lubricated bearing needs to be 3.4 times longer than oil-lubricated bearing, but its friction coefficient and power loss are only 11.7% of those of oil-lubricated bearing and its maximum temperature rise is less than 2 K, much lower than 96.76 K corresponding to oil lubrication.
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Haral, Ashwini. „An Experimental Study of Tribological Behavior of Journal Bearing Material under Powder and Granular Lubrication“. International Journal for Research in Applied Science and Engineering Technology 9, Nr. 8 (31.08.2021): 2553–57. http://dx.doi.org/10.22214/ijraset.2021.37811.
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Abstract: Proper lubrication of mechanical components is very important for the reliable efficiency and useful life. The working temperature of the components can affect the lubricating oil and can degrade the lubricating characteristics of oil. This paper presents the experimental investigation on tribological behaviour of journal bearing material. Two types of additives are used in lubricating oili.e., powder and granular types of additives. The investigation is carried out on pin-on-disc apparatus to determine the wear and coefficient of friction. The statistical analysis is performed using design of experiments and Taguchi robust design to determine the optimum parameters of lubricating additives. It is found that for constant speed of 400 rpm with 5% concentration with varying size the granular lubrication have lower values than powder lubrication for all load conditions Keywords: Lubrication, pin-on-disc, Taguchi, additives.
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Zhang, Ke, Xianchao Wu, Xiaotian Bai, Zinan Wang, Defang Zou und Jie Sun. „Effect of the Lubrication Parameters on the Ceramic Ball Bearing Vibration in Starved Conditions“. Applied Sciences 10, Nr. 4 (12.02.2020): 1237. http://dx.doi.org/10.3390/app10041237.
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The thickness of the oil film in ceramic ball bearings varies greatly at starved lubrication conditions, thus leading to non-uniform contact between the balls and raceways in the circumference. The lubrication parameters have a direct impact on the thickness of the oil film and then affect the dynamic characteristics of the ceramic ball bearings. A nonlinear dynamic model of ceramic ball bearing with limited lubrication is presented in this paper, and parametric studies on the effect of lubrication parameters are conducted. In starved conditions, the uneven contact between the ball and ring leads to changes in vibration, and the inner ring vibration is applied to evaluate the degree of starved lubrication. The results show that as the oil quantity increases, the bearing stiffness increases and results in increased peak frequency. As the oil quantity decreases, the thickness of the oil film reduces, resulting in the bearing vibration increase. The research findings provide a theoretical reference for ceramic ball bearing design and have guided significance for improving the service performance of ceramic ball bearings.
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Wang, Li Jun, Xiao Kang Yan, Fei Hu Li und Zi Xin Dong. „Numerical Simulation of Magnetic Fluid Lubrication“. Advanced Materials Research 154-155 (Oktober 2010): 1498–501. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.1498.
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This paper was concerned with theoretical analysis and the static characteristics of the journal bearing lubricated with magnetic fluid. A general Reynolds equation based on magnetic fluid model is obtained, which can be easily extended to other non-Newtonian fluids and this equation can provide theoretical basis for hydrodynamic analysis of magnetic fluid journal bearings. For the case of static loaded magnetic journal bearings, the influence of magnetic fluid effects on the lubrication performance is studied under various eccentricity ratios, magnetic intensity and concentration. The numerical results show that: with the increasing of concentration, the bearing capacity is obviously increased; the increase magnitude is larger when the eccentricity ratio is large. Under the effect of magnetic field, the bearing capacity increasing with the increasing of magnetic field intensity. When the eccentricity is small, the side leakage is highly decreased. It can be completely eliminate by appropriately designing the bearing geometry and the magnetic field which can’t be existed in normal journal bearings.
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Liu, Jian Hua. „Study on Material Application of Water Lubrication Bearings in Pump“. Advanced Materials Research 485 (Februar 2012): 381–84. http://dx.doi.org/10.4028/www.scientific.net/amr.485.381.
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In recent years, water lubrication bearing has widely used in pump as support elements， its reliability and life have important influence on pump running, while the material of water lubrication bearing is one of main factors to limit its application. So integrating with its application of bearing lubrication for pump，the paper introduced the characteristics of the water lubrication friction pair and the wear mechanism of materials. Simultaneously characteristics and the scope of application of materials were introduced such as metal materials, plastic, ceramic, wood etc. The use principle and the future research direction was put forward for material of the water lubrication bearings.
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Yu, Xiao Dong, Hong Jun Xiang, Xiao Zhong Lou, Xiu Li Meng, Hui Jiang, Wei Dong Ji, Chang Qing Yang und Xian Zhu Sun. „Influence Research of Velocity on Lubricating Properties of Sector Cavity Multi-Pad Hydrostatic Thrust Bearing“. Advanced Materials Research 129-131 (August 2010): 1104–8. http://dx.doi.org/10.4028/www.scientific.net/amr.129-131.1104.
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Lubricating characteristics of sector cavity multi-pad hydrostatic thrust bearing are affected significantly by velocity, poor design can cause lubricant film rupture and dry friction, even leading to failure of hydrostatic bearing tribology. For this problem, the Computational Fluid Dynamics and the lubrication theory have been used to analyze velocity characteristics of the parameters such as cavity pressure of oil, oil cavity flow and film thickness, to gain relationship between velocity and lubricating properties of sector cavity multi-pad hydrostatic thrust bearing, avoiding the occurrence of hydrostatic bearing tribological failure. It is shown that along with the speed of the worktable increasing, the flow of lubricant oil caused by inertia and centrifugal force become larger, the flow of efflux from the oil cavity also become larger, causing the pressure drop of the oil cavity, the thinning of the film thickness, the occurrence of film rupture and dry friction and failure of hydrostatic bearing tribology. The study provides the basic data for the hydrostatic thrust bearing design, the lubrication and the experiment, implements of the prediction of the hydrostatic thrust bearing lubrication velocity characteristics, and reaches the purpose of reducing economic loss.
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DellaCorte, Christopher, Antonio R. Zaldana und Kevin C. Radil. „A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery“. Journal of Tribology 126, Nr. 1 (01.01.2004): 200–207. http://dx.doi.org/10.1115/1.1609485.
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Foil air bearings are self-acting hydrodynamic bearings which rely upon solid lubricants to reduce friction and minimize wear during sliding which occurs at start-up and shut-down when surface speeds are too low to allow the formation of a hydrodynamic air film. This solid lubrication is typically accomplished by coating the nonmoving foil surface with a thin, soft polymeric film. The following paper introduces a systems approach in which the solid lubrication is provided by a combination of self lubricating shaft coatings coupled with various wear resistant and lubricating foil coatings. The use of multiple materials, each providing different functions is modeled after oil-lubricated hydrodynamic sleeve bearing technology which utilizes various coatings and surface treatments in conjunction with oil lubricants to achieve optimum performance. In this study, room temperature load capacity tests are performed on journal foil air bearings operating at 14,000 rpm. Different shaft and foil coating technologies such as plasma sprayed composites, ceramic, polymer and inorganic lubricant coatings are evaluated as foil bearing lubricants. The results indicate that bearing performance is improved through the individual use of the lubricants and treatments tested. Further, combining several solid lubricants together yielded synergistically better results than any material alone.
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Wang, You-Qiang, Xiu-Jiang Shi und Li-Jing Zhang. „Experimental and numerical study on water-lubricated rubber bearings“. Industrial Lubrication and Tribology 66, Nr. 2 (04.03.2014): 282–88. http://dx.doi.org/10.1108/ilt-11-2011-0098.
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Purpose – Water-lubricated rubber bearing is one of the most appropriate bearings for underwater use. The most popular design used widely today is the straight fluted rubber bearing. The special configuration leads to partial hydrodynamic lubrication and low load capacity. A new bearing bush structure with two cavities which is favorable for constructing continuous hydrodynamic lubrication was designed and studied. The paper aims to discuss these issues. Design/methodology/approach – A new bearing bush structure with two cavities which is favorable for constructing continuous hydrodynamic lubrication was designed. The apparatus for studying the tribological behaviors of the two types of water-lubricated rubber bearings has been devised and established in the paper. The experimental studies on the tribological properties of the rubber bearings have been conducted under different loads and velocities. The eccentricity ratio of the new structure rubber bearing with two cavities was measured in experiment and the load capacity was calculated by numerical simulation. Findings – The experimental results show that the friction coefficient decreases with increasing velocity; the friction coefficient increases sharply with the rising temperature, the friction coefficient increases at first and then decreases with increasing load for fluted rubber bearings. The numerical results were in good agreement with the experimental results. The numerical results show that complete hydrodynamic lubrication can be formed in the new designed rubber bearing with two cavities. The experimental and numerical results all indicate that there is an appropriate bearing clearance which the friction coefficient is minimum and the load capacity is maximum. Originality/value – A new bearing bush structure with two cavities which is beneficial to constructing continuous hydrodynamic lubrication film was designed. A new apparatus for studying the tribological behaviors of the two types of water-lubricated rubber bearings has been devised and established. Experimental and numerical study on the new structure rubber bearing were conducted in the paper.
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Kim, Byung-Jik, und Kyung-Woong Kim. „Thermo-Elastohydrodynamic Analysis of Connecting Rod Bearing in Internal Combustion Engine“. Journal of Tribology 123, Nr. 3 (04.01.2001): 444–54. http://dx.doi.org/10.1115/1.1353181.
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A comprehensive method of thermo-elastohydrodynamic lubrication analysis for connecting rod bearings is proposed, which includes thermal distortion as well as elastic deformation of the bearing surface. Lubrication film temperature is treated as a time-dependent, two-dimensional variable which is averaged over the film thickness, while the bearing temperature is assumed to be time-independent and three-dimensional. It is assumed that a portion of the heat generated by viscous dissipation in the lubrication film is absorbed by the film itself, and the remainder flows into the bearing structure. Mass-conserving cavitation algorithm is applied, and the effect of variable viscosity is included in the Reynolds equation. Simulation results of the connecting rod bearing of an internal combustion engine are presented. It is shown that the predicted level of the thermal distortion is as large as that of the elastic deformation and the bearing clearance, and that the thermal distortion has remarkable effects on the bearing performance. Therefore, the thermo-elastohydrodynamic lubrication analysis is strongly recommended to predict the performance of connecting rod bearings in internal combustion engines.
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Van Treuren, K. W., D. N. Barlow, W. H. Heiser, M. J. Wagner und N. H. Forster. „Investigation of Vapor-Phase Lubrication in a Gas Turbine Engine“. Journal of Engineering for Gas Turbines and Power 120, Nr. 2 (01.04.1998): 257–62. http://dx.doi.org/10.1115/1.2818113.
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The liquid oil lubrication system of current aircraft jet engines accounts for approximately 10–15 percent of the total weight of the engine. It has long been a goal of the aircraft gas turbine industry to reduce this weight. Vapor-Phase Lubrication (VPL) is a promising technology to eliminate liquid oil lubrication. The current investigation resulted in the first gas turbine to operate in the absence of conventional liquid lubrication. A phosphate ester, commercially known as DURAD 620B, was chosen for the test. Extensive research at Wright Laboratory demonstrated that this lubricant could reliably lubricate rolling element bearings in the gas turbine engine environment. The Allison T63 engine was selected as the test vehicle because of its small size and bearing configuration. Specifically, VPL was evaluated in the number eight bearing because it is located in a relatively hot environment, in line with the combustor discharge, and it can be isolated from the other bearings and the liquid lubrication system. The bearing was fully instrumented and its performance with standard oil lubrication was documented. Results of this baseline study were used to develop a thermodynamic model to predict the bearing temperature with VPL. The engine was then operated at a ground idle condition with VPL with the lubricant misted into the #8 bearing at 13 ml/h. The bearing temperature stabilized at 283°C within 10 minutes. Engine operation was continued successfully for a total of one hour. No abnormal wear of the rolling contact surfaces was found when the bearing was later examined. Bearing temperatures after engine shutdown indicated the bearing had reached thermodynamic equilibrium with its surroundings during the test. After shutdown bearing temperatures steadily decreased without the soakback effect seen after shutdown in standard lubricated bearings. In contrast, the oil-lubricated bearing ran at a considerably lower operating temperature (83°C) and was significantly heated by its surroundings after engine shutdown. In the baseline tests, the final bearing temperatures never reached that of the operating VPL system.
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Gao, L. M., Q. E. Meng, F. Liu, J. Fisher und Z. M. Jin. „The effect of aspherical geometry and surface texturing on the elastohydrodynamic lubrication of metal-on-metal hip prostheses under physiological loading and motions“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 224, Nr. 12 (23.06.2010): 2627–36. http://dx.doi.org/10.1243/09544062jmes2193.
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As an alternative material combination, metal-on-metal (MOM) hip replacement has attracted a revived interest due to its very low wear rates. In this article, an elastohydrodynamic lubrication analysis is performed for an MOM hip replacement with specific geometrical designs: a macro Alpharabola geometry of the cup bearing surface and micro-dimples on the head surface. The corresponding numerical methodology is presented and full numerical solutions are obtained. The effect of the macro- and micro-geometrical designs on the lubrication performance is investigated, under both simplified and physiological walking conditions. The real physiological loading and motion conditions are important to be considered when optimizing the conformity-associated geometry of hip bearings. The Alpharabola geometry of cup bearing surface is found to significantly improve the lubricating film thickness and reduce hydrodynamic pressure of MOM hip implants, when the Alpharabola minimum radius is aligned with the loading direction. Dimpled surface texturing has an adverse effect in a fluid film lubrication regime under the conditions considered in this study.
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Xing, Hui, Hui Zhang, Qili Wu und Shu Lin Duan. „Full Shafting-Based Elastohydrodynamic Lubrication Simulation for Main Bearings of Marine Diesel Engine“. Advanced Materials Research 479-481 (Februar 2012): 1119–23. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.1119.
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To predict and analyze accurately the lubrication characteristics and its influencing factors of main bearing for large low-speed two-stroke marine diesel engine, based on EHD lubrication model of dynamically loaded bearing, coupling simulation between EHD and MBD for main bearing of marine diesel engine was carried out. Systemic models were established separately considering the independent crankshaft of diesel engine and the full shafting of propulsion power plant. Main bearing load, peak oil film pressure, oil film pressure distribution, MOFT and orbital path in one working cycle under rated working conditions were investigated, and simulation results were compared based on both models. The results show that, if the impact of full shafting was considered, the lubrication characteristics of No.8 main bearing changed significantly, the lubrication characteristics of other main bearings were similar as the simulation results of the independent crankshaft model.
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Pleskach, V., und V. Ol’shanetskii. „About design and use of powder plain bearings“. Innovative Materials and Technologies in Metallurgy and Mechanical Engineering, Nr. 2 (18.03.2021): 45–49. http://dx.doi.org/10.15588/1607-6885-2020-2-6.
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Purpose. Optimization of methods of design, calculation and use of slip bearings; elaboration of recommendations on the use of powder materials and lubricants for the production of slip bearings.
Research methods. Analysis of existing calculations of slip bearings, of efficiency of the bearing under conditions of self-lubrication and features of using hydrodynamic lubrication theory for calculations of slip bearings in the presence of liquid lubrication.
Results. The area of predominant application of slip bearings, their main elements are clarified and described; recommendations on the sizes of structural elements of bearings are given. The main types of slipping friction and their relationship with the bearing design and operating conditions are analyzed.
The possible composition of powder materials for slip bearings, the interdependence of bearing porosity and the viscosity of the oil used to ensure the of its longevity is analyzed. Recommendations for the design of bearings in conditions of liquid friction are given. Generalized methodology for calculating the efficiency of slip bearings is proposed.
Based on the theory of hydrodynamic lubrication, a method for calculating slip bearings for liquid lubrication conditions, which provides optimal operating conditions is proposed.
Scientific novelty. Optimized selection of powder material and structure to improve lubrication conditions is proposed. The analysis of the influence of the chemical composition of the oil to ensure maximum adhesion of this oil with a bearing surface is resulted; the analysis of the influence of the chemical composition of the oil to ensure maximum adhesion of this oil with a bearing surface, as well as mathematical dependencies that make it possible to adjust the composition of the oil by adding specially selected microadditives is resulted. Generalized approaches to the method of calculation of powder slip bearings, which operating under different friction conditions are proposed.
Practical value. Practical methods of designing and calculating slip bearings from powder materials are offered.
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Xiang, Chang Zheng, Yu Juan Wang und Yun Fei Chen. „Hydrodynamic Lubrication in a Nanoscale Bearing“. Advanced Materials Research 60-61 (Januar 2009): 1–5. http://dx.doi.org/10.4028/www.scientific.net/amr.60-61.1.
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Nonequilibrium molecular dynamics simulation is used to simulate the hydrodynamics lubrication in the nanoscale bearing. A physical model of the nanascale bearing that the thin liquid water film confined between two solid walls has been set up. The simulation results indicate that the hydrodynamic pressure profiles as the macroscopic state are formed in nanoscale bearings. The hydrodynamic pressure increases with increasing shear velocity, and corresponding load capacity also increases with increasing sliding velocity of the upper driven wall. These results are in accordance with classical Reynolds’ theory about hydrodynamic lubrication. On the other hand, the shear thinning behavior of the liquid water film appears, so that effective viscosity decreases under high shear velocity. Although effective viscosity of water film decreases under high shear velocity, this phenomenon doesn’t affect the hydrodynamic lubrication of the nanoscale bearing.
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Wang, Xin Rong, Xiao Hai Li, Ya Chao Cui und Li Hua Yang. „Design of Main Pump Motor’s Water Lubricated Bearing and Research on its Lubrication Performances“. Advanced Materials Research 538-541 (Juni 2012): 1971–74. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.1971.
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Water-lubricated thrust bearing is a key component of certain main pump motor. In this paper, the right structure of water-lubricated thrust graphite bearings is designed based on low viscosity hydrodynamic lubrication theory by combining the bearings running working condition, and the frictional accessory material is also determined by theoretical analysis and test. The factors influencing lubrication performances of water-lubricated thrust bearings are analyzed; the methods improving lubrication performances are put forward to guarantee that water-lubricated thrust graphite bearings have the good lubrication performances, good carrying capacity and longer work life.
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Wang, You Qiang, und Chao Li. „Numerical Analysis of Hydrodynamic Lubrication on Water-Lubricated Rubber Bearings“. Advanced Materials Research 299-300 (Juli 2011): 12–16. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.12.
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Water lubricated rubber bearings are one of the most appropriate bearings for underwater use. The most popular design used widely today is the straight fluted rubber bearing. The special configuration leads to partial hydrodynamic lubrication and low load capacity. A new bearing bush structure which is favorable for constructing continuous hydrodynamic lubrication was designed and produced for experiment in the paper. The eccentricity ratio of the new structure rubber bearing was measured under different loads in experiment. Used the measured eccentricity ratios, the load capacity was calculated by numerical simulation and compared with the given test values. The calculated values were in good agreement with the given test results. The results show that complete hydrodynamic lubrication can be formed in the new designed rubber bearing. The experimental results also indicate that there is an appropriate bearing clearance which the load capacity is up to the maximum.
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Ursolov, Aleksandr, Yuriy Batrak und Wieslaw Tarelko. „Application of the Optimization Methods to the Search of Marine Propulsion Shafting Global Equilibrium in Running Condition“. Polish Maritime Research 26, Nr. 3 (01.09.2019): 172–80. http://dx.doi.org/10.2478/pomr-2019-0058.
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Abstract Full-film hydrodynamic lubrication of marine propulsion shafting journal bearings in running condition is discussed. Considerable computational difficulties in non-linear determining the quasi-static equilibrium of the shafting are highlighted. To overcome this problem the approach using two optimization methods (the particle swarm method and the interior point method) in combination with the specially developed relaxation technique is proposed. The developed algorithm allows to calculate marine propulsion shafting bending with taking into account lubrication in all journal bearings and exact form of journal inside bearings, compared to results of most of the publications which consider lubrication only in the aft most stern tube bearing and assume rest of bearings to be represented by points. The calculation results of typical shafting design with four bearings are provided. The significance of taking into account lubrication in all bearings is shown, specifically more exact values of bearings’ reactions, shafting deflections, minimum film thickness and maximum hydrodynamic pressure in the stern tube bearing in case of considering lubrication in all bearings.
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Santos, I. F., und F. H. Russo. „Tilting-Pad Journal Bearings With Electronic Radial Oil Injection“. Journal of Tribology 120, Nr. 3 (01.07.1998): 583–94. http://dx.doi.org/10.1115/1.2834591.
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This paper gives a theoretical treatment of the problem of journal bearings modeling connected to electronic oil injection into the bearing gap. The feasibility of influencing the static behavior of hydrodynamic forces by means of such oil injection is investigated. The lubricant is injected into the bearing gap by two mechanisms of lubrication: the conventional hydrodynamic lubrication and through orifices distributed along the bearing surface (active lubrication in the radial direction). By controlling the pressure of the oil injection, it is possible to get large variations in the active hydrodynamic forces; such effects could be useful for reducing vibrations in rotating machines.
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Li, Yang, Zhaojun Yang, Fei Chen und Jin Zhao. „Effect of air inlet flow rate on flow uniformity under oil-air lubrication“. Industrial Lubrication and Tribology 70, Nr. 2 (12.03.2018): 282–89. http://dx.doi.org/10.1108/ilt-12-2016-0296.
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Purpose This paper aims to investigate the effects of air inlet flow rate on the bearing cavity and operating conditions during the oil-air lubrication. Design/methodology/approach A model of oil-air lubrication of rolling bearings is established using computational fluid dynamics numerical simulation. Moreover, temperature and vibration experiments are carried out for comparisons and validation. Findings Results suggest that the velocity and pressure distributions of the oil-air flow inside the chamber are not uniform. Moreover, the uniform decreases with increasing air inlet flow rate. The non-uniform oil distribution inside the bearing significantly influences the bearing temperature rise and lubrication effect. Furthermore, the decrease in pressure uniformity enhances the vibration intensity and increases the amplitude of the vibration acceleration by more than 40 per cent. Increasing the air inlet flow rate improves lubrication and cooling efficiency but produces intense vibrations. Originality/value A method of establishing rolling bearings model under oil-air lubrication is presented in the paper. The effect of air inlet flow rate on flow uniform under oil-air lubrication has been researched insightfully. The results provide a useful reference to improve the oil-air lubrication system and enhance the operational stability of the motorized spindle.
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Yusof, N. F. M., und Z. M. Ripin. „The Effect of Lubrication on the Vibration of Roller Bearings“. MATEC Web of Conferences 217 (2018): 01004. http://dx.doi.org/10.1051/matecconf/201821701004.
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Proper lubrication is crucial to ensure smooth operation in machineries. In rolling bearing, the improper lubrication may induce high friction and vibration level due to metal to metal contact between the rolling elements. In this study, the roller bearings with and without lubrication are investigated. the natural surface degradation of the roller bearing is monitored and the surface roughness is measured for the lubricant film thickness calculation. the film thickness is determined by the Hamrock-Dowson equation which showed that the grease lubricated bearing operated under the elastro-hydrodynamic lubrication, with the ratio of lubrication film thickness to the surface roughness of λ in the range of 0.9 to 3.65. the un-lubricated bearing was damaged after 20 minutes whereas the grease lubricated bearing continued to operate for 6600 minutes. the observation under microscope showed that the surface underwent smoothening process where the surface roughness decreases initially (running-in state) followed by roughening at the steady state where the surface roughness increases. At damage, the value of λ = 0.9 can be associated with the high level of the bearing vibration. the increase of vibration level becomes rapid at the critical value of λ = 1.6. As such the overall vibration level of the bearing can be related to the surface degradation and low film thickness.
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Wang, Jin Li, Li Quan Li und Shao Gang Liu. „The Research on Oil-Air Lubrication in Grooved Sliding Bearing“. Key Engineering Materials 572 (September 2013): 384–87. http://dx.doi.org/10.4028/www.scientific.net/kem.572.384.
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Many Factors affect the oil-air lubrication of sliding bearing such as oil supply, air pressure, load, bearing structure and so on. In order to study the effects of bearing structure on oil-air lubrication in sliding bearing, the oil-air lubrication and oil lubrication experiments of grooved sliding bearing have been done by using friction-abrasion testing machine. By means of measuring the temperature rise and the friction coefficient of grooved sliding bearing on oil-air lubrication and oil lubrication with different level of load at the same rotating speed, the results obtained show that the friction coefficient of oil-air lubrication with oil supply 30ml/h, air pressure 0.25MPa is almost the same as oil lubrication with oil supply 1.4L/h. The oil-air lubrication temperature rise is much lower than the oil lubrication in grooved sliding bearing with the same experimental conditions.
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K.P., Lijesh, Muzakkir S.M., Harish Hirani und Gananath Doulat Thakre. „Control on wear of journal bearing operating in mixed lubrication regime using grooving arrangements“. Industrial Lubrication and Tribology 68, Nr. 4 (13.06.2016): 458–65. http://dx.doi.org/10.1108/ilt-11-2015-0162.
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Purpose The journal bearings subjected to heavy load and slow speed operate in mixed lubrication regime causing contact between the interacting surfaces and resulting in wear. Complexity of wear behavior and lack of unifying theory/model make wear-control very challenging. Design/methodology/approach In the present research work, theoretical and experimental investigations have been conducted to explore the effect of grooving arrangements on the wear behavior of journal bearing operating in mixed lubrication regime. The theoretical model of Hirani (2005) that uses mass conserving cavitation algorithm has been used to determine the bearing eccentricity for different groove arrangements (with varying groove location and extent) for identifying a groove arrangement that minimizes the wear. The wear tests on the grooved bearings were conducted after suitable running-in of the new bearings on a fully automated journal bearing test set-up. A load and speed combination required to operate the bearing in mixed lubrication was used. The performance of different arrangement of bearing was evaluated by measuring their weight loss after the test. Findings Wear was significantly reduced with the use of proper groove arrangement for a bearing operating in mixed lubrication regime. Originality/value The improvement in bearing performance by providing grooves has been the subject matter of several studies in the past, but these studies were confined to the hydrodynamic operative regime of the bearing. In the present work, seven different combinations of axial and radial groove arrangement were tried, which has not been reported in any other work.
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Zhou, Hui, Jun Zheng, Ji Xing Hu, Rui Peng Sang und Zhi Hua Wan. „Study of MoS2-Ti Composite Coatings Applied in Precision Ball Bearings“. Advanced Materials Research 538-541 (Juni 2012): 281–85. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.281.
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708C Ball bearings were made of 9Cr18 steel which had precision of class 4, MoS2-Ti composite coatings were deposited on inner and outer races of ball bearings by unbalanced magnetron sputtering system, and bearing cages were made of PTFE-based self-lubricating polymers. Bearing’s tribological torques as a function of storage time in high humidity environment were studied by using LHU-2 thermal & humidity test chamber and Bearing 2000 torque measurement device. Developing bearing vacuum performance test rig to research bearing’s torque as a function of running time, bearings were dismantled after test and using XPS to analyze the surfaces of bearing’s races and balls. The results show that storied in the environment of 30°C, 85% RH, bearing’s running torques increased proportionally as the storage time went on. When run-in the bearings which were storied for 440 days, the start and average running torques of bearings could come back to the level which was the same as the test start, but the fluctuation of bearing’s average running torque increased. Running in one direction at the speed of 650 r/min, in vacuum environment (~10-4Pa) and ambient temperature, tested bearings showed good running performance with low friction torque varied only between 1g·cm~2 g·cm until to the test ended at 1.872×108 revolutions. XPS analysis showed that a stable and sustainable solid lubrication system was established among bearing’s races, balls and cages.
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Czaban, Adam, und Andrzej Miszczak. „Simulations of the Influence of the Heat Flux at the Shaft Surface of the Conical Slide Bearing on Its Hydrodynamic Lubrication and Operating Parameters“. Journal of KONES 26, Nr. 4 (01.12.2019): 29–37. http://dx.doi.org/10.2478/kones-2019-0086.
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AbstractThe aim of this work is to investigate, how in the adopted model of hydrodynamic lubrication of a conical slide bearing, the change of the heat flux value at the bearing shaft, affects bearing operating parameters. In this research, the authors use, the known from the literature, Reynolds type equation, describing the stationary hydrodynamic lubrication process of a conical slide bearing. The analytical, solutions, that determine the components of the lubricating oil velocity vector and the equation (analytical solution of energy equation) determining the three-dimensional temperature distribution in the lubrication gap, was also adopted from previous works. In order to obtain numerical solutions, the Newton’s method was used, and the derivatives in the Reynolds type equation were approximated by the finite differences. An application of the method of subsequent approximations allowed considering the influence of temperature, pressure and shearing rate on the viscosity of lubricating oil. The considerations were performed by adopting the Reynolds condition of the hydrodynamic oil film. It was tested, how the assumed value of the heat flux on the bearing shaft surface affects the values of the obtained operating parameters, i.e. the transverse and longitudinal component of the load carrying capacity, friction force and coefficient of friction.
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Sun, Qi Guo, Yue Fei Wang, Ying Wang und Hong Bo Lv. „Comparing of Temperatures of Rolling Bearing under the Oil-Air Lubrication to the Spray Lubrication“. Applied Mechanics and Materials 395-396 (September 2013): 763–68. http://dx.doi.org/10.4028/www.scientific.net/amm.395-396.763.
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The heat generating mechanism inside the cavity of rolling bearing is analyzed and the convective heat transfer coefficient of bearing raceway surface in different rotational speed is calculated under the oil-air lubrication and the spray lubrication in this paper. The fluid domain geometry model of deep groove ball bearing SKF6208 is established, employing the flow field module in Workbench. The comparing simulations of the temperatures of rolling bearing cavity under the oil-air lubrication to the spray lubrication are done in different rotational speed. The simulation results show that the highest temperature of bearing cavity with the oil-air lubrication is almost the same to the spray lubrication when the bearing rotational speed is lower, and the highest temperature of bearing cavity with the oil-air lubrication is far lower than the spray lubrication when the bearing rotational speed is higher. Those conclusions verify the advantages of the oil-air lubrication in high rotational speed.
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Han, Yanxiang, und Yonghong Fu. „Influence of micro-grooves on the lubrication performance of a misaligned bearing“. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, Nr. 6 (01.08.2019): 887–99. http://dx.doi.org/10.1177/1350650119867506.
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Surface texturing for improving the lubrication performance of journal bearings has been widely investigated in the last two decades. In practical applications, the misalignment of a journal bearing occurs due to the asymmetric bearing load, elastic deflection, manufacturing tolerances, and installation errors. However, there has been little discussion on the influence of grooves on the lubrication performance of misaligned bearings. In the present work, numerical predictions of lubrication performances are presented to test the influence of the grooves. Based on the JFO boundary condition, a mass conservation algorithm is implemented to automatically determine the position of oil film rupture and reformation. The load-carrying capacity, friction force, friction coefficient, and bearing moment are computed numerically. The influence of angular position of the groove is first conducted in a misaligned bearing. Subsequently, the groove depth and width are investigated with different values of [Formula: see text] and [Formula: see text] ratios, respectively.
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Yu, Xiang Jun, Jing Yang, Yong Shuai Wang und Ke Li. „Hydrokinetic Analysis of Crankshaft Main Bearings in High-Speed Gasoline Engine“. Advanced Materials Research 680 (April 2013): 322–26. http://dx.doi.org/10.4028/www.scientific.net/amr.680.322.
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To a particular inline-four high-speed gasoline engine as the research object, main bearing lubrication analysis model of four-cylinder engine is based on AVL-Excite Power Unit software and couples the mechanical dynamics with lubricating fluid dynamics. On the basis of this model, we are focusing on the influence of parameters such as grease groove width on the engine main bearing lubrication performance. According to the analysis of simulation results on the minimum film thickness and maximum film pressure, and combined with the analysis report of disassembling the engine, it is easy to know why bearing bushes wear and provide the basis for the optimized design of the crankshaft main bearing. Improving design of the main bearing is more useful for operating requirement.
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Fukui, S., R. Matsuda und R. Kaneko. „On the Physical Meanings of Λ/Q˜p0 and σ/Q˜p0 in Molecular Gas Film Lubrication Problems“. Journal of Tribology 118, Nr. 2 (01.04.1996): 364–69. http://dx.doi.org/10.1115/1.2831310.
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To estimate molecular gas film lubrication (MGL) characteristics, we propose a modified bearing number Λ′ and a modified squeeze number σ′, which are, respectively, the conventional bearing Λ and squeeze number σ divided by the relative Poiseuille flow rate Q˜p0. Using Λ′ and σ′, the linearized MGL problem can be reduced to the continuum gas film lubrication problem and the MGL characteristics can be exactly estimated, if the characteristic flow rate corresponding to the spacing, Q˜p0, is known. For nonlinear MGL problems, the lubrication characteristics can be verified to be roughly estimated by Λ′ and σ′ both in rectangular slider bearings and in circular squeeze-film thrust bearings.
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Miszczak, Andrzej, und Krzysztof Wierzcholski. „Operating Parameters of a Slide Bearing with Parabolic-Shaped Slide Surfaces with Consideration of the Stochastic Changes in the Lubrication Gap Height“. Journal of KONES 26, Nr. 4 (01.12.2019): 171–78. http://dx.doi.org/10.2478/kones-2019-0105.
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AbstractIn this article, the authors present the equations of the hydrodynamic theory for a slide bearing with parabolic-shaped slide surfaces. The lubricating oil is characterized by non-Newtonian properties, i.e. an oil for which, apart from the classic oil viscosity dependence on pressure and temperature, also an effect of the shear rate is taken into account. The first order constitutive equation was adopted for considerations, where the apparent viscosity was described by the Cross equation. The analytical solution uses stochastic equations of the momentum conservation law, the stream continuity and the energy conservation law. The solution takes into account the expected values of the hydrodynamic pressure EX[p(ϕ,ζ)], of the temperature EX[T(ϕ,y,ζ)], of the velocity value of lubricating oil EX[vi(ϕ,y,ζ)], of the viscosity of lubricating oil EX[ηT(ϕ,y,ζ)] and of the lubrication gap height EX[εT(ϕ,ζ)]. It was assumed, that the oil is incompressible and the changes in its density and thermal conductivity were omitted. A flow of lubricating oil was laminar and non-isothermal. The research concerned the parabolic slide bearing of finite length, with a smooth sleeve surface, with a full wrap angle. The aim of this work is to derive the stochastic equations, that allow to determine the temperature distribution, hydrodynamic pressure distribution, velocity vector components, load carrying capacity, friction force and friction coefficient, in the parabolic sliding bearing, lubricated with non-Newton (Cross) oil, including the stochastic changes in the lubrication gap height. The paper presents the results of analytical and numerical calculation of flow and operating parameters in parabolic sliding bearings, taking into account the stochastic height of the lubrication gap. Numerical calculations were performed using the method of successive approximations and finite differences, with own calculation procedures and the Mathcad 15 software.
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Turis, Ján, Pavel Beňo und Witold Biały. „The Optimal Tribotechnical Factors in the Design of Machines – Environmental Element in the Production Systems“. Management Systems in Production Engineering 26, Nr. 4 (01.12.2018): 207–11. http://dx.doi.org/10.1515/mspe-2018-0033.
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Abstract The article deals with the experimental detection of the tribotechnical parameters for two different types of sliding bearings which are intended for operation without an additional lubrication due to the increasing requirements in ecology and environment. The dominant tribotechnical parameters of the self-lubricating bearing are the coefficient of friction and temperature. To determine these parameters, an experimental method was applied in this paper. The introductory part deals with materials of self-lubricating sliding bearings, their properties and usage. The experimental part consists of the evaluation of friction characteristics and geometric change of a surface after sliding pairs were being worn. Experimental examined sliding pairs comprise a sliding bearing and the shaft. The aim of this research was to determine the effect of radial force on tribotechnical parameters in order to predict the behavior of examined sliding bearings in real operating conditions.