{"title":"Formation of Nano Interface by Sliding between Hard Coatings and Metals in MoDTC Contained Oil","authors":"Ryo Koike, Atsushi Suzuki, K. Kurihara, K. Adachi","doi":"10.2474/trol.17.1","DOIUrl":"https://doi.org/10.2474/trol.17.1","url":null,"abstract":"","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"99 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2022-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85328187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Malki, S. Larbi, S. Boubendir, D. Hammoudi, R. Bennacer
{"title":"Elastic Deformation Effects on Self-Lubricating Journal Bearings Using Pseudo-Plastic Lubricants","authors":"M. Malki, S. Larbi, S. Boubendir, D. Hammoudi, R. Bennacer","doi":"10.2474/trol.16.299","DOIUrl":"https://doi.org/10.2474/trol.16.299","url":null,"abstract":"","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"22 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77632421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The advent of smart materials and modern control theory has seen the rapid development of ultrasonic motors over the last decades. They have become promising precision driving components due to their unique piezoelectric transduction and friction drive mechanisms. This review summarizes the synthesis of the key technical aspects, research efforts, conclusions, and challenges that need to be highlighted concerning ultrasonic motor structural design and tribological performance. The analysis shows that the development of ultrasonic motor with new principles is in the ascendant. Simplifying the body structure, developing advanced friction contact models and life prediction models, developing new and environmentally friendly friction materials, and developing customized tribological testing devices are goals and tasks that should be considered in the future design of efficient ultrasonic motors.
{"title":"Ultrasonic Motors Structural Design and Tribological Performance -A Review","authors":"J. Puoza, Rajalingam Sakthivelsamy","doi":"10.2474/trol.16.286","DOIUrl":"https://doi.org/10.2474/trol.16.286","url":null,"abstract":"The advent of smart materials and modern control theory has seen the rapid development of ultrasonic motors over the last decades. They have become promising precision driving components due to their unique piezoelectric transduction and friction drive mechanisms. This review summarizes the synthesis of the key technical aspects, research efforts, conclusions, and challenges that need to be highlighted concerning ultrasonic motor structural design and tribological performance. The analysis shows that the development of ultrasonic motor with new principles is in the ascendant. Simplifying the body structure, developing advanced friction contact models and life prediction models, developing new and environmentally friendly friction materials, and developing customized tribological testing devices are goals and tasks that should be considered in the future design of efficient ultrasonic motors.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"47 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78235028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evaluating the Elastic Moduli of Ultra-Thin Liquid Perfluoropolyether Lubricant Films on Diamond-Like Carbon Films Using Ar-Gas Cluster Ion Beams","authors":"H. Tani, Renguo Lu, S. Koganezawa, N. Tagawa","doi":"10.2474/trol.16.309","DOIUrl":"https://doi.org/10.2474/trol.16.309","url":null,"abstract":"","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"7 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87235041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Li-li Wang, Huan Geng, Wei Zhang, X. Ge, Mengxue He
Taking the elliptical bearing as the research object, adopting the mixture two-phase flow model and energy equation, the pressure characteristics, the cavitation distribution and the thermal effect of elliptical bearing with different ellipticities are analyzed. The results show that the maximum temperature rise of elliptical bearing is lower than cylindrical bearing. The optimal ellipticity of elliptical bearing is 0.6, the upper and lower bush of elliptical bearing can form the effective oil film, the proportion of cavitation area and volume is small, the maximum temperature rise of oil film is lowest, which is conducive to the stable operation of journal bearings.
{"title":"Effect of Ellipticity on Cavitation Mechanism and Thermal Effect of Elliptical Journal Bearings","authors":"Li-li Wang, Huan Geng, Wei Zhang, X. Ge, Mengxue He","doi":"10.2474/trol.16.279","DOIUrl":"https://doi.org/10.2474/trol.16.279","url":null,"abstract":"Taking the elliptical bearing as the research object, adopting the mixture two-phase flow model and energy equation, the pressure characteristics, the cavitation distribution and the thermal effect of elliptical bearing with different ellipticities are analyzed. The results show that the maximum temperature rise of elliptical bearing is lower than cylindrical bearing. The optimal ellipticity of elliptical bearing is 0.6, the upper and lower bush of elliptical bearing can form the effective oil film, the proportion of cavitation area and volume is small, the maximum temperature rise of oil film is lowest, which is conducive to the stable operation of journal bearings.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"75 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86359839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ball bearings on the main shaft of rocket engine turbopumps which supply cryogenic propellants to the main combustion chamber are critical elements of the entire propulsion system of a rocket. A self-lubricating ball bearing with a retainer made of glass-cloth-polytetrafluoroethylene (PTFE) laminate has been used in turbopumps developed in Japan. In the operation of the turbopump, the bearing heat generation is possible to cause sudden temperature rises of bearing elements which finally result in bearing seizure. Therefore, it is important to predict the accurate bearing heat generation under various operating conditions. In this research, the bearing heat generation operated in cryogenic hydrogen was experimentally investigated under the various operating conditions where the rotational speed and the bearing coolant condition were changed. In addition, the bearing heat generation was compared with that theoretically predicted on a numerical model of mechanical losses. It was finally clarified that the bearing heat generation is influenced dominantly by the friction loss on balls and the drag loss on an inner race.
{"title":"Heat Generation in Cryogenic Turbopump Bearing","authors":"Hiromitsu Kakudo, S. Takada, T. Hirayama","doi":"10.2474/trol.16.271","DOIUrl":"https://doi.org/10.2474/trol.16.271","url":null,"abstract":"Ball bearings on the main shaft of rocket engine turbopumps which supply cryogenic propellants to the main combustion chamber are critical elements of the entire propulsion system of a rocket. A self-lubricating ball bearing with a retainer made of glass-cloth-polytetrafluoroethylene (PTFE) laminate has been used in turbopumps developed in Japan. In the operation of the turbopump, the bearing heat generation is possible to cause sudden temperature rises of bearing elements which finally result in bearing seizure. Therefore, it is important to predict the accurate bearing heat generation under various operating conditions. In this research, the bearing heat generation operated in cryogenic hydrogen was experimentally investigated under the various operating conditions where the rotational speed and the bearing coolant condition were changed. In addition, the bearing heat generation was compared with that theoretically predicted on a numerical model of mechanical losses. It was finally clarified that the bearing heat generation is influenced dominantly by the friction loss on balls and the drag loss on an inner race.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"6 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88380637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Takumi Kani, T. Tokoroyama, N. Umehara, M. Murashima, Woo-Young Lee, K. Yagishita
In general, several mechanical parts are subjected to friction and wear. To prevent wear and high friction coefficient under lubrication, additives can work to reduce friction force, to build up thin film on surfaces which is so-called tribofilm. Recently, Diamond-Like Carbon (DLC) is focused because it has excellent low friction and high wear proof as solid lubricant. However, several researchers already reported that tetrahedral amorphous carbon (ta-C) showed abnormal wear when it rubbed with glycerol mono-oleate (GMO) that is a kind of additive, although it showed very low friction coefficient. To improve tribological properties, new additives were developed that had both phosphate-oxide structure derived from ZnDTP which had high wear resistance and hydroxy group derived from GMO in one structure. To clarify the effects of the additives, friction tests were performed fixed-roller-on-disk type rotating friction tester. In the friction tests, hydrogenated amorphous carbon (a-C:H) disks, and a-C:H coated rollers were used under boundary lubrication condition at 20-80°C. Friction tests were conducted in Poly-α-olefin (PAO) oil with each GMO and the additives. The results exhibited that a-C:H gave ultra-low friction with the additive. Elemental analysis of the surface showed that tribofilm of phosphorus and oxygen was detected on the a-C:H surface in the additive used condition.
{"title":"The Tribological Properties of Hydrogenated DLC Coating Lubrication with Additive Having Glycerol and Phosphonate Structure","authors":"Takumi Kani, T. Tokoroyama, N. Umehara, M. Murashima, Woo-Young Lee, K. Yagishita","doi":"10.2474/trol.16.263","DOIUrl":"https://doi.org/10.2474/trol.16.263","url":null,"abstract":"In general, several mechanical parts are subjected to friction and wear. To prevent wear and high friction coefficient under lubrication, additives can work to reduce friction force, to build up thin film on surfaces which is so-called tribofilm. Recently, Diamond-Like Carbon (DLC) is focused because it has excellent low friction and high wear proof as solid lubricant. However, several researchers already reported that tetrahedral amorphous carbon (ta-C) showed abnormal wear when it rubbed with glycerol mono-oleate (GMO) that is a kind of additive, although it showed very low friction coefficient. To improve tribological properties, new additives were developed that had both phosphate-oxide structure derived from ZnDTP which had high wear resistance and hydroxy group derived from GMO in one structure. To clarify the effects of the additives, friction tests were performed fixed-roller-on-disk type rotating friction tester. In the friction tests, hydrogenated amorphous carbon (a-C:H) disks, and a-C:H coated rollers were used under boundary lubrication condition at 20-80°C. Friction tests were conducted in Poly-α-olefin (PAO) oil with each GMO and the additives. The results exhibited that a-C:H gave ultra-low friction with the additive. Elemental analysis of the surface showed that tribofilm of phosphorus and oxygen was detected on the a-C:H surface in the additive used condition.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"328 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73138759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Tokoroyama, T. Nishimoto, Y. Murakami, Akiyuki Honda, Hideaki Mitsui, Y. Terai, M. Murashima, Woo-Young Lee, N. Umehara
In this study, nano-scratch tests were conducted using atomic force microscope (AFM) to clarify the hardness of a tribofilm derived from an additive (Fluid A or Fluid B in automatic-transmission fluid) formed on an SKS3 cold work tool steel substrate surface. Comparisons between nano-indentation hardness tests and AFM nano-scratch tests were performed for each specimen. Prior to these tests, the tribofilms on the SKS3 substrate were examined with energy-dispersive spectroscopy (EDS). In order to calculate the hardness of the tribofilm from the nano-scratch results, we assumed that the AFM diamond tip acted as an abrasive to plough the tribofilm. The phosphorous-derived tribofilm formed from Fluid A was harder than the sulfur-derived tribofilm from Fluid B, and it was calculated that the phosphorous-derived tribofilm was approximately 2.64 GPa and the sulfur-derived tribofilm was 1.89 GPa. After 10 nanoindentation hardness tests on each tribofilm, the maximum indentation depth into the tribofilm formed from Fluid A was approximately 31 nm, while it was approximately 36 nm for Fluid B. These results are qualitatively consistent with the hardness results obtained by the AFM nano-scratch test method.
{"title":"Evaluation of Mechanical Characteristics of Tribofilm Formed on the Surface of Metal Material Due to Friction under Lubrication with Automatic Transmission Fluid","authors":"T. Tokoroyama, T. Nishimoto, Y. Murakami, Akiyuki Honda, Hideaki Mitsui, Y. Terai, M. Murashima, Woo-Young Lee, N. Umehara","doi":"10.2474/trol.16.255","DOIUrl":"https://doi.org/10.2474/trol.16.255","url":null,"abstract":"In this study, nano-scratch tests were conducted using atomic force microscope (AFM) to clarify the hardness of a tribofilm derived from an additive (Fluid A or Fluid B in automatic-transmission fluid) formed on an SKS3 cold work tool steel substrate surface. Comparisons between nano-indentation hardness tests and AFM nano-scratch tests were performed for each specimen. Prior to these tests, the tribofilms on the SKS3 substrate were examined with energy-dispersive spectroscopy (EDS). In order to calculate the hardness of the tribofilm from the nano-scratch results, we assumed that the AFM diamond tip acted as an abrasive to plough the tribofilm. The phosphorous-derived tribofilm formed from Fluid A was harder than the sulfur-derived tribofilm from Fluid B, and it was calculated that the phosphorous-derived tribofilm was approximately 2.64 GPa and the sulfur-derived tribofilm was 1.89 GPa. After 10 nanoindentation hardness tests on each tribofilm, the maximum indentation depth into the tribofilm formed from Fluid A was approximately 31 nm, while it was approximately 36 nm for Fluid B. These results are qualitatively consistent with the hardness results obtained by the AFM nano-scratch test method.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"270 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86414887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tomonobu Komoriya, Ryosuke Ichimura, T. Kochi, Michitaka Yoshihara, Masataka Sakai, D. Dong, Y. Kimura
The life of rolling bearings can be limited by sudden increase in friction torque due to exhaustion of lubricant after long-term operations. With the purpose of developing grease having long “service life”, research has been conducted with angular contact ball bearings lubricated with urea greases, and the present First Report describes experimental work. The life was determined on FAG-FE9 rolling bearing grease testers, and considerable difference in the life was found among the greases with different type thickeners. Observation of bearings by interrupting the run inferred the following scenario. In a short churning period, grease was re-distributed to form a lump on the front face of the outer ring and thin layers on some other parts of the bearing. The lump served as an oil reservoir, and the oil bled from it infiltrated through the thin layer on the outer ring to lubricate the raceways. A part of the oil was then carried by the balls to lubricate the sliding interface between the cage and the balls and, when this lubrication became insufficient, seizure initiated to limit the life.
{"title":"Service Life of Lubricating Grease in Ball Bearings (Part 1) Behavior of Grease and Its Base Oil in a Ball Bearing","authors":"Tomonobu Komoriya, Ryosuke Ichimura, T. Kochi, Michitaka Yoshihara, Masataka Sakai, D. Dong, Y. Kimura","doi":"10.2474/trol.16.236","DOIUrl":"https://doi.org/10.2474/trol.16.236","url":null,"abstract":"The life of rolling bearings can be limited by sudden increase in friction torque due to exhaustion of lubricant after long-term operations. With the purpose of developing grease having long “service life”, research has been conducted with angular contact ball bearings lubricated with urea greases, and the present First Report describes experimental work. The life was determined on FAG-FE9 rolling bearing grease testers, and considerable difference in the life was found among the greases with different type thickeners. Observation of bearings by interrupting the run inferred the following scenario. In a short churning period, grease was re-distributed to form a lump on the front face of the outer ring and thin layers on some other parts of the bearing. The lump served as an oil reservoir, and the oil bled from it infiltrated through the thin layer on the outer ring to lubricate the raceways. A part of the oil was then carried by the balls to lubricate the sliding interface between the cage and the balls and, when this lubrication became insufficient, seizure initiated to limit the life.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"45 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83060198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A previously developed and validated rolling bearing life model that separates the surface and the subsurface survivals is now adapted to account for superior bearing steel that allows bearings to operate in the region near contact pressures of 3 GPa and speeds of ndm = 3 × 10 (n is the rotational speed in rpm and dm is the bearing mean diameter in mm), common of high-load and high-speeds applications like modern spindle bearings. The adapted model is verified with the support of endurance testing and its range of application is also verified with the support of a full non-seizure test. The adapted model can now be used in the bearing selection process for those tough application conditions.
{"title":"Application of a Rolling Bearing Life Model with Surface and Subsurface Survival to Hybrid Bearings in High-Load and High-Speed Applications","authors":"G. Morales-Espejel, A. Félix-Quiñonez","doi":"10.2474/trol.16.216","DOIUrl":"https://doi.org/10.2474/trol.16.216","url":null,"abstract":"A previously developed and validated rolling bearing life model that separates the surface and the subsurface survivals is now adapted to account for superior bearing steel that allows bearings to operate in the region near contact pressures of 3 GPa and speeds of ndm = 3 × 10 (n is the rotational speed in rpm and dm is the bearing mean diameter in mm), common of high-load and high-speeds applications like modern spindle bearings. The adapted model is verified with the support of endurance testing and its range of application is also verified with the support of a full non-seizure test. The adapted model can now be used in the bearing selection process for those tough application conditions.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"11 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2021-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83001795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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