Wenwu Lei, Wentao Tang, Xiaoyu Mo, Z. Tian, Peikang Shen, T. Ouyang
The restricted adsorption capacity of ordinary graphene at high temperature limits its application in engine lubrication. To address this, nitrogen-doped element-modified graphene with strong adsorption and superior lubricating properties is prepared by a bottom-up chemical strategy in this study. The reciprocating tribometer is aimed at simulating the piston operating environment to determine the lubrication performance of nitrogen-doped graphene. The characterization and analysis for the wear marks are performed by means of depth-of-field microscope, scanning electron microscope, energy dispersive spectrometer and other instruments. The experimental data demonstrates that the friction-reduction and anti-wear properties of PAO 6 base oil are enhanced by 22.4% and 56.9% (100 °C), respectively, after the addition of 0.4 wt% nitrogen-doped graphene. Besides, the abrasive and adhesive wear are significantly reduced, which is attributed to its inter-layer slip along the sliding direction and superior adsorption performance. Finally, the interfacial lubrication mechanism of lubricant protective film under high temperature conditions is revealed.
{"title":"Tribological evaluation of few-layer nitrogen-doped graphene as an efficient lubricant additive on engine cylinder liner: Experiment and mechanism investigation","authors":"Wenwu Lei, Wentao Tang, Xiaoyu Mo, Z. Tian, Peikang Shen, T. Ouyang","doi":"10.1115/1.4056905","DOIUrl":"https://doi.org/10.1115/1.4056905","url":null,"abstract":"\u0000 The restricted adsorption capacity of ordinary graphene at high temperature limits its application in engine lubrication. To address this, nitrogen-doped element-modified graphene with strong adsorption and superior lubricating properties is prepared by a bottom-up chemical strategy in this study. The reciprocating tribometer is aimed at simulating the piston operating environment to determine the lubrication performance of nitrogen-doped graphene. The characterization and analysis for the wear marks are performed by means of depth-of-field microscope, scanning electron microscope, energy dispersive spectrometer and other instruments. The experimental data demonstrates that the friction-reduction and anti-wear properties of PAO 6 base oil are enhanced by 22.4% and 56.9% (100 °C), respectively, after the addition of 0.4 wt% nitrogen-doped graphene. Besides, the abrasive and adhesive wear are significantly reduced, which is attributed to its inter-layer slip along the sliding direction and superior adsorption performance. Finally, the interfacial lubrication mechanism of lubricant protective film under high temperature conditions is revealed.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48166208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Traditional bump foil bearing, though widely used, is considered to have the problem of inadequate load capacity due to the effect of foil sag between adjacent bumps. In this paper, the thick top foil is applied to cope with the heavy load conditions, which has one order of magnitude larger top foil thickness than traditional top foil. Thick plate and curve shell models are developed to calculate the load carrying performance of thick top foil bearing based on contact mechanics, and the sag ratio is introduced to describe the degree of foil sag and estimate the bearing load capacity. The impacts of top foil thickness on the stiffness of bearings in different sizes as well on the adaptability to rotor tilt are discussed. The results indicate that the thick top foil (tt=2mm) bearing performs a nearly 100% enhanced load capacity at small gas film thickness whether rotor tilts or not. Thick top foil will increase the bearing stiffness of small size (d=35 mm) and tends to has little influence on large size bearing stiffness (d=70 mm).
{"title":"Investigations of the Bump Foil Bearing with Thick Top Foil Based on Contact Mechanics","authors":"Jie Li, Changlin Li, Jia-min Du","doi":"10.1115/1.4056900","DOIUrl":"https://doi.org/10.1115/1.4056900","url":null,"abstract":"\u0000 Traditional bump foil bearing, though widely used, is considered to have the problem of inadequate load capacity due to the effect of foil sag between adjacent bumps. In this paper, the thick top foil is applied to cope with the heavy load conditions, which has one order of magnitude larger top foil thickness than traditional top foil. Thick plate and curve shell models are developed to calculate the load carrying performance of thick top foil bearing based on contact mechanics, and the sag ratio is introduced to describe the degree of foil sag and estimate the bearing load capacity. The impacts of top foil thickness on the stiffness of bearings in different sizes as well on the adaptability to rotor tilt are discussed. The results indicate that the thick top foil (tt=2mm) bearing performs a nearly 100% enhanced load capacity at small gas film thickness whether rotor tilts or not. Thick top foil will increase the bearing stiffness of small size (d=35 mm) and tends to has little influence on large size bearing stiffness (d=70 mm).","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42460082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. G. Salunkhe, R. Desavale, S. Khot, Nitesh P. Yelve
Roller bearing failure can result in downtime or the entire outage of rotating machinery. As a result, a timely incipient bearing defect must be diagnosed to ensure optimal process operation. Modern condition monitoring necessitates the use of Deep Independent Component Analysis to diagnose incipient bearing failure. This paper presents a Deep Independent Component Analysis method based on variational Modal Decomposition (VMD-ICA) is to diagnose incipient bearing defect. On a newly established test setup for rotor bearings, Fast Fourier Techniques are used to extract the vibration responses of bearings that have been artificially damaged using Electro-chemical Machining. VMD techniques diminish the noise of the measurement data, to decompose data processed into multiple sub-data sets for extracting incipient defect characteristics. The simplicity of the VMD-ICA model enriched the precision of diagnosis correlated to the experimental results with weak fault characteristic signal and noise interference. Moreover, Deep VMD-ICA has additionally demonstrated strong performance in comparison to experimental results and is useful for monitoring the condition of industrial machinery.
{"title":"A Novel Incipient Fault Detection Technique for Roller Bearing Using Deep Independent Component Analysis and Variational Modal Decomposition","authors":"V. G. Salunkhe, R. Desavale, S. Khot, Nitesh P. Yelve","doi":"10.1115/1.4056899","DOIUrl":"https://doi.org/10.1115/1.4056899","url":null,"abstract":"\u0000 Roller bearing failure can result in downtime or the entire outage of rotating machinery. As a result, a timely incipient bearing defect must be diagnosed to ensure optimal process operation. Modern condition monitoring necessitates the use of Deep Independent Component Analysis to diagnose incipient bearing failure. This paper presents a Deep Independent Component Analysis method based on variational Modal Decomposition (VMD-ICA) is to diagnose incipient bearing defect. On a newly established test setup for rotor bearings, Fast Fourier Techniques are used to extract the vibration responses of bearings that have been artificially damaged using Electro-chemical Machining. VMD techniques diminish the noise of the measurement data, to decompose data processed into multiple sub-data sets for extracting incipient defect characteristics. The simplicity of the VMD-ICA model enriched the precision of diagnosis correlated to the experimental results with weak fault characteristic signal and noise interference. Moreover, Deep VMD-ICA has additionally demonstrated strong performance in comparison to experimental results and is useful for monitoring the condition of industrial machinery.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44793020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiawei Wang, Sen Jiang, Jiuqi Huang, Wencai Xiong, Jingwei Hu, Zhaozhe Meng, Ange Nsilani Kouediatouka, G. Dong
The hydrostatic journal bearing's recess pressure is to be determined using a novel approach. This method treats the circumferential bearing lands on both sides of recesses as infinitely long bearings, and the axial bearing lands on both sides of recesses as infinitely short bearings. The newton-Cotes integral formula is used to solve the definite integration. By this simplification, a new analytical expression of recess pressure considering the hydrodynamic effect on bearing land is obtained. The recess pressure versus eccentricity, supply oil pressure, recess wrap angle, and attitude angle solved by the new method is compared with that calculated by the finite difference method and Liang's method from two kinds of four-recess hydrostatic journal bearing compensated by capillary restrictor. The results indicate that the new process has high accuracy and its precision isn't almost affected by the parameters change. Moreover, the new method has low time consumption.
{"title":"Simplified calculation of recess pressure considering the hydrodynamic effect","authors":"Jiawei Wang, Sen Jiang, Jiuqi Huang, Wencai Xiong, Jingwei Hu, Zhaozhe Meng, Ange Nsilani Kouediatouka, G. Dong","doi":"10.1115/1.4056740","DOIUrl":"https://doi.org/10.1115/1.4056740","url":null,"abstract":"\u0000 The hydrostatic journal bearing's recess pressure is to be determined using a novel approach. This method treats the circumferential bearing lands on both sides of recesses as infinitely long bearings, and the axial bearing lands on both sides of recesses as infinitely short bearings. The newton-Cotes integral formula is used to solve the definite integration. By this simplification, a new analytical expression of recess pressure considering the hydrodynamic effect on bearing land is obtained. The recess pressure versus eccentricity, supply oil pressure, recess wrap angle, and attitude angle solved by the new method is compared with that calculated by the finite difference method and Liang's method from two kinds of four-recess hydrostatic journal bearing compensated by capillary restrictor. The results indicate that the new process has high accuracy and its precision isn't almost affected by the parameters change. Moreover, the new method has low time consumption.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48699742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wyatt L Peterson, F. Sadeghi, A. Meinel, H. Grillenberger
A test rig was designed and developed to assess the lubrication and friction of a single cylindrical roller and a conformal cage pocket. The roller was lubricated via oil bath in a sealed housing. Inner and outer bearing raceway pieces were fixed above and below the roller to mimic the internal geometry of an actual bearing. The cage pocket was made from transparent acrylic to look inside the cage and observe oil flow during operation. A six-axis load cell was used to measure the torque generated by the entire test rig with and without the cage pocket, and used to isolate the friction of the cage pocket. Experiments were conducted to investigate the effects of roller-pocket clearance, roller-race clearance, and roller oil submersion level at rest. Results suggest that roller bearing cage pocket friction increases with decreasing pocket clearance, increasing oil availability, and increasing operating speed. The oil was observed to coalesce into stable striations inside the cage pocket for many operating conditions. Striation width was observed to decrease with increasing speed, increasing pocket clearance, and decreasing oil availability. The striations were summarized by oil volume fraction inside the cage pocket, which decreased with increasing speed, decreasing pocket clearance and decreasing oil availability. The current results provide new information about oil behavior inside roller bearing cage pockets during operation, and an approach is presented to estimate roller bearing cage pocket friction.
{"title":"Investigation of Roller Bearing Cage Pocket Lubrication and Friction","authors":"Wyatt L Peterson, F. Sadeghi, A. Meinel, H. Grillenberger","doi":"10.1115/1.4056649","DOIUrl":"https://doi.org/10.1115/1.4056649","url":null,"abstract":"\u0000 A test rig was designed and developed to assess the lubrication and friction of a single cylindrical roller and a conformal cage pocket. The roller was lubricated via oil bath in a sealed housing. Inner and outer bearing raceway pieces were fixed above and below the roller to mimic the internal geometry of an actual bearing. The cage pocket was made from transparent acrylic to look inside the cage and observe oil flow during operation. A six-axis load cell was used to measure the torque generated by the entire test rig with and without the cage pocket, and used to isolate the friction of the cage pocket. Experiments were conducted to investigate the effects of roller-pocket clearance, roller-race clearance, and roller oil submersion level at rest. Results suggest that roller bearing cage pocket friction increases with decreasing pocket clearance, increasing oil availability, and increasing operating speed. The oil was observed to coalesce into stable striations inside the cage pocket for many operating conditions. Striation width was observed to decrease with increasing speed, increasing pocket clearance, and decreasing oil availability. The striations were summarized by oil volume fraction inside the cage pocket, which decreased with increasing speed, decreasing pocket clearance and decreasing oil availability. The current results provide new information about oil behavior inside roller bearing cage pockets during operation, and an approach is presented to estimate roller bearing cage pocket friction.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46129665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuai Yang, Jiang Xueqing, S. Zhang, Hong Guo, S. Cen
The conical bearing can withstand both journal and axial load because of the conical-shape fluid film, and an investigation concerning the thermodynamic lubrication and stability properties is proposed for a conical hydrostatic/hydrodynamic floating ring bearing theoretically and experimentally. The finite element method is coupled with the finite difference method to solve the variable-viscosity Reynolds equations, thermal energy equations, and the corresponding boundary conditions for the inner and outer films in a floating ring equilibrium state, and the conical bearing-rotor dynamic and stability performance models are built up with the perturbation theory and Routh-Hurwitz method. The primary characteristics parameters that are obtained under different operational conditions suggested that there presents a significant temperature gradient distribution over the lubricated domain, the thermal effects decrease the load carrying capacity, friction power loss, and stiffness and damping coefficients, and the viscous dissipation influences the variation of threshold instability speed with eccentricity and reduces its maximum value. In experiments, the temperature distributions of the oil leakage flow are measured to compare with the calculated results for the validation of the mathematic model using an infrared thermal imager, and the thermal effects need to be taken into consideration for the bearing lubrication analysis and design.
{"title":"On the Lubrication and Stability Behaviors of a Conical Hybrid Floating Ring Bearing with Thermal Effects","authors":"Shuai Yang, Jiang Xueqing, S. Zhang, Hong Guo, S. Cen","doi":"10.1115/1.4056631","DOIUrl":"https://doi.org/10.1115/1.4056631","url":null,"abstract":"\u0000 The conical bearing can withstand both journal and axial load because of the conical-shape fluid film, and an investigation concerning the thermodynamic lubrication and stability properties is proposed for a conical hydrostatic/hydrodynamic floating ring bearing theoretically and experimentally. The finite element method is coupled with the finite difference method to solve the variable-viscosity Reynolds equations, thermal energy equations, and the corresponding boundary conditions for the inner and outer films in a floating ring equilibrium state, and the conical bearing-rotor dynamic and stability performance models are built up with the perturbation theory and Routh-Hurwitz method. The primary characteristics parameters that are obtained under different operational conditions suggested that there presents a significant temperature gradient distribution over the lubricated domain, the thermal effects decrease the load carrying capacity, friction power loss, and stiffness and damping coefficients, and the viscous dissipation influences the variation of threshold instability speed with eccentricity and reduces its maximum value. In experiments, the temperature distributions of the oil leakage flow are measured to compare with the calculated results for the validation of the mathematic model using an infrared thermal imager, and the thermal effects need to be taken into consideration for the bearing lubrication analysis and design.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48810241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The current work investigates the influence of real lubricant density-pressure behavior on the dynamic response of elastohydrodynamic lubricated conjunctions. Such a response is often based on a non-realistic universal equation of state, despite longstanding evidence of its lack of support by measurements. A finite element framework is employed to investigate the damping and stiffness characteristics of line contact EHD lubricating films, subject to a harmonic loading. Both the equivalent stiffness and damping coefficients of lubricating films are found to increase with the base applied external load, and its amplitude of oscillation. They decrease however with increasing mean entrainment speed and load oscillation frequency. That is, they both increase as lubricant films get thinner. By comparison with the real density-pressure response of a highly compressible silicon oil, the universal equation of state is shown to underestimate the lubricant film's stiffness and damping characteristics. The relative deviations in equivalent damping and stiffness coefficients can reach up to about 12% and 25%, respectively. Therefore, realistic lubricant characteristics should always be considered. In particular, the use of the universal equation of state should not be taken for granted, as is customary in the EHL literature. Lubricant density-pressure response is not of a secondary nature, when it comes to predicting the dynamic performance characteristics of EHL conjunctions.
{"title":"Influence of Real Lubricant Density-Pressure Behavior on the Dynamic Response of Elastohydrodynamic Lubricated Conjunctions","authors":"J. Issa, W. Habchi","doi":"10.1115/1.4056629","DOIUrl":"https://doi.org/10.1115/1.4056629","url":null,"abstract":"\u0000 The current work investigates the influence of real lubricant density-pressure behavior on the dynamic response of elastohydrodynamic lubricated conjunctions. Such a response is often based on a non-realistic universal equation of state, despite longstanding evidence of its lack of support by measurements. A finite element framework is employed to investigate the damping and stiffness characteristics of line contact EHD lubricating films, subject to a harmonic loading. Both the equivalent stiffness and damping coefficients of lubricating films are found to increase with the base applied external load, and its amplitude of oscillation. They decrease however with increasing mean entrainment speed and load oscillation frequency. That is, they both increase as lubricant films get thinner. By comparison with the real density-pressure response of a highly compressible silicon oil, the universal equation of state is shown to underestimate the lubricant film's stiffness and damping characteristics. The relative deviations in equivalent damping and stiffness coefficients can reach up to about 12% and 25%, respectively. Therefore, realistic lubricant characteristics should always be considered. In particular, the use of the universal equation of state should not be taken for granted, as is customary in the EHL literature. Lubricant density-pressure response is not of a secondary nature, when it comes to predicting the dynamic performance characteristics of EHL conjunctions.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43329162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The reasonable electric current and graphite content will slow down the wear failure of friction pair and prolong service life of slip ring. To study the wear behaviors of copper/graphite composites under different currents, the composites with graphite content of 30%, 25%, 20% and 15%, denoted as CG30, CG25, CG20 and CG15, were prepared as the material of slip ring. A series of friction and wear tests were carried out, and wear topography and friction vibration were measured. With the increase of electric current, the wear mechanism of CG30 is adhesive wear, and that of CG25 changes from adhesive wear to combined effect of adhesive wear and arc ablation. The anti-wear effect of CG30 is better than CG25. However, the ability of arc suppression of CG25 is better than that of CG30. Therefore, in order to improve service life of slip ring, it is recommended to choose the composite CG25.
{"title":"Effect of electric current and graphite content on the wear behaviors of copper/graphite composites","authors":"Rui Zhu, Xue Zuo, Yuankai Zhou, Wenxin Xie","doi":"10.1115/1.4056630","DOIUrl":"https://doi.org/10.1115/1.4056630","url":null,"abstract":"\u0000 The reasonable electric current and graphite content will slow down the wear failure of friction pair and prolong service life of slip ring. To study the wear behaviors of copper/graphite composites under different currents, the composites with graphite content of 30%, 25%, 20% and 15%, denoted as CG30, CG25, CG20 and CG15, were prepared as the material of slip ring. A series of friction and wear tests were carried out, and wear topography and friction vibration were measured. With the increase of electric current, the wear mechanism of CG30 is adhesive wear, and that of CG25 changes from adhesive wear to combined effect of adhesive wear and arc ablation. The anti-wear effect of CG30 is better than CG25. However, the ability of arc suppression of CG25 is better than that of CG30. Therefore, in order to improve service life of slip ring, it is recommended to choose the composite CG25.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43562787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The calculating method for fatigue life of rolling bearings is based on the theory of Lundberg and Palmgren. The rated life is determined from the ratio of the dynamic load rating of the bearing to the dynamic equivalent load. However, in actual applications, flaking damage may occur earlier than this rated life. For example, surface initiated flaking may occur due to contamination in the lubricant. In addition, differences in the internal clearance of bearings are also thought to influence the occurrence of surface initiated flaking. This study aims to investigate the effect of different internal clearance on surface initiated flaking in tapered roller bearings. Firstly, rotating tests were conducted on combination tapered roller bearings with dented raceways under several axial clearances different from the standard condition. Secondly, the surface profiles of the bearings before and after the tests were compared to investigate the relationship between the distribution of flaking area and the axial clearance. Furthermore, the effect of axial clearance on the surface initiated flaking life was clarified from the comparison between the results of the rotating tests. Finally, the theoretical and experimental lives were compared. As a result, it has been found that when the axial clearance is excessively large, the distribution of flaking is biased toward the large diameter side of the outer raceway. In addition, it has been demonstrated that the bearing life is substantially affected by the axial clearance, and that the bearing life shortens as the axial clearance increases.
{"title":"Effects of Axial Clearance on Surface Initiated Flaking in Tapered Roller Bearings","authors":"Ken Takahashi, Takafumi Nagatomo","doi":"10.1115/1.4056627","DOIUrl":"https://doi.org/10.1115/1.4056627","url":null,"abstract":"\u0000 The calculating method for fatigue life of rolling bearings is based on the theory of Lundberg and Palmgren. The rated life is determined from the ratio of the dynamic load rating of the bearing to the dynamic equivalent load. However, in actual applications, flaking damage may occur earlier than this rated life. For example, surface initiated flaking may occur due to contamination in the lubricant. In addition, differences in the internal clearance of bearings are also thought to influence the occurrence of surface initiated flaking. This study aims to investigate the effect of different internal clearance on surface initiated flaking in tapered roller bearings. Firstly, rotating tests were conducted on combination tapered roller bearings with dented raceways under several axial clearances different from the standard condition. Secondly, the surface profiles of the bearings before and after the tests were compared to investigate the relationship between the distribution of flaking area and the axial clearance. Furthermore, the effect of axial clearance on the surface initiated flaking life was clarified from the comparison between the results of the rotating tests. Finally, the theoretical and experimental lives were compared. As a result, it has been found that when the axial clearance is excessively large, the distribution of flaking is biased toward the large diameter side of the outer raceway. In addition, it has been demonstrated that the bearing life is substantially affected by the axial clearance, and that the bearing life shortens as the axial clearance increases.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45251549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Honing is one of the abrasive-based machining processes to remove material through the asperity interaction between numerous stochastic grains distributed on oilstone (also called honing stone) and workpiece. Therefore, the oilstone surface topography characterized with grain morphology, size, posture and position distribution, protrusion heights and etc., is of great significance to understand honing mechanism in terms of establishing an accurate kinematic model and further analyzing the oilstone property's impact on honing process and honed surface texture characteristics including groove density, roughness heights and plateau/valley amplitudes. Conventionally, two typical approaches have been employed to establish the surface topography of abrasive-based cutting tools: experimentally microscopic observation and backward modeling/simulation from the assumed ideal distribution laws such as Gaussian or uniform distribution for stochastic grain characteristics. The first method is usually time-consuming and only measures surface topography within rather small area; whereas the second one is highly dependent on the authenticity of assumed statistical distribution laws. To overcome these weaknesses, the research proposed a functional forward method (FFM) to accurately predict surface topography of oilstone based on simulating its manufacturing processes in succession to avoid distributional assumptions and geometrical simplification. The methodology takes into consideration five important stochastic characteristics of oilstone including grain morphology, size, posture, position distribution and grain wear during honing process, to guarantee the credibility, authenticity and generality of the surface topography generated from honing. Based on the oilstone surface topography, a kinematic simulation method (KISM) was proposed to analyze the honed surface texture characteristics of cylinder bore with oilstone samples under different stirring times. Therefore, the methodology bridges oilstone manufacturing parameters, oilstone surface topography and further the honed surface texture to provide a fresh insight into the parameter's optimization of oilstone manufacturing process by achieving a better control on the honed surface texture of cylinder bore.
{"title":"Oilstone Processing and Its Impact on the Surface Texture of Cylinder Bore","authors":"Xin Zhang, Xijuan Liu, Xueping Zhang","doi":"10.1115/1.4056628","DOIUrl":"https://doi.org/10.1115/1.4056628","url":null,"abstract":"\u0000 Honing is one of the abrasive-based machining processes to remove material through the asperity interaction between numerous stochastic grains distributed on oilstone (also called honing stone) and workpiece. Therefore, the oilstone surface topography characterized with grain morphology, size, posture and position distribution, protrusion heights and etc., is of great significance to understand honing mechanism in terms of establishing an accurate kinematic model and further analyzing the oilstone property's impact on honing process and honed surface texture characteristics including groove density, roughness heights and plateau/valley amplitudes. Conventionally, two typical approaches have been employed to establish the surface topography of abrasive-based cutting tools: experimentally microscopic observation and backward modeling/simulation from the assumed ideal distribution laws such as Gaussian or uniform distribution for stochastic grain characteristics. The first method is usually time-consuming and only measures surface topography within rather small area; whereas the second one is highly dependent on the authenticity of assumed statistical distribution laws. To overcome these weaknesses, the research proposed a functional forward method (FFM) to accurately predict surface topography of oilstone based on simulating its manufacturing processes in succession to avoid distributional assumptions and geometrical simplification. The methodology takes into consideration five important stochastic characteristics of oilstone including grain morphology, size, posture, position distribution and grain wear during honing process, to guarantee the credibility, authenticity and generality of the surface topography generated from honing. Based on the oilstone surface topography, a kinematic simulation method (KISM) was proposed to analyze the honed surface texture characteristics of cylinder bore with oilstone samples under different stirring times. Therefore, the methodology bridges oilstone manufacturing parameters, oilstone surface topography and further the honed surface texture to provide a fresh insight into the parameter's optimization of oilstone manufacturing process by achieving a better control on the honed surface texture of cylinder bore.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49585836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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