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Effects of grease types on vibration and acoustic emission of defective linear-guideway type recirculating ball bearings / Ohta, Hiroyuki in Transactions of the ASME . Journal of tribology, Vol. 133 N° 2 (Avril 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 133 N° 2 (Avril 2011) . - 09 p. Titre : Effects of grease types on vibration and acoustic emission of defective linear-guideway type recirculating ball bearings Type de document : texte imprimé Auteurs : Ohta, Hiroyuki, Auteur ; Shinya Hayashi, Auteur ; Kato, Soichiro, Auteur Année de publication : 2012 Article en page(s) : 09 p. Note générale : Tribology Langues : Anglais (eng) Mots-clés : Acoustic  emission  Ball  bearings  Greases  Impact  testing  Lubrication  Vibrations  Viscosity Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper deals with effects of grease types on vibrations and acoustic emissions (AEs) of linear-guideway type recirculating ball bearings with a millimeter-sized artificial defect in the carriage. First, the vibration and AE of one normal bearing without a defect (Type N) and six defective bearings (Types D1–D6) were measured using a linear velocity of 1 m/s. Three types of grease are used for the lubrication of test bearings. The experimental results show that the vibration and AE amplitudes (the pulse amplitudes, the root-mean-square (RMS) values, and component amplitudes in the spectra) of both the normal and defective bearings have a tendency to be reduced when a grease with higher base oil viscosity is used. Under the same type of grease, the RMS values of the vibrations and AE of the defective bearings increase as the defect angle increases. However, the increases of the RMS values due to increased defect angle (the increasing rates of the RMS values) are reduced when a grease with higher base oil viscosity is used. To explain these experimental results, grease impact tests are carried out. The grease impact tests show that a grease with higher base oil viscosity reduces the impact velocity and the maximum impact forces. This implies that a grease with higher base oil viscosity generate greater viscous resistance to balls in the test bearings then reduces the ball impact forces in the ball circulation collisions and ball-defect collisions. Because of the reduction of the ball impact forces, both the vibration and AE amplitudes as well as the increasing rate of the RMS values are reduced. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...] [article] Effects of grease types on vibration and acoustic emission of defective linear-guideway type recirculating ball bearings [texte imprimé] / Ohta, Hiroyuki, Auteur ; Shinya Hayashi, Auteur ; Kato, Soichiro, Auteur . - 2012 . - 09 p. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 133 N° 2 (Avril 2011) . - 09 p. Mots-clés : Acoustic  emission  Ball  bearings  Greases  Impact  testing  Lubrication  Vibrations  Viscosity Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper deals with effects of grease types on vibrations and acoustic emissions (AEs) of linear-guideway type recirculating ball bearings with a millimeter-sized artificial defect in the carriage. First, the vibration and AE of one normal bearing without a defect (Type N) and six defective bearings (Types D1–D6) were measured using a linear velocity of 1 m/s. Three types of grease are used for the lubrication of test bearings. The experimental results show that the vibration and AE amplitudes (the pulse amplitudes, the root-mean-square (RMS) values, and component amplitudes in the spectra) of both the normal and defective bearings have a tendency to be reduced when a grease with higher base oil viscosity is used. Under the same type of grease, the RMS values of the vibrations and AE of the defective bearings increase as the defect angle increases. However, the increases of the RMS values due to increased defect angle (the increasing rates of the RMS values) are reduced when a grease with higher base oil viscosity is used. To explain these experimental results, grease impact tests are carried out. The grease impact tests show that a grease with higher base oil viscosity reduces the impact velocity and the maximum impact forces. This implies that a grease with higher base oil viscosity generate greater viscous resistance to balls in the test bearings then reduces the ball impact forces in the ball circulation collisions and ball-defect collisions. Because of the reduction of the ball impact forces, both the vibration and AE amplitudes as well as the increasing rate of the RMS values are reduced. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...]

Running torque of ball bearings with polymer lubricant (running torque formulas of deep groove ball bearings under axial loads) / Masayuki Kanatsu in Transactions of the ASME . Journal of tribology, Vol. 130 N° 4 (Octobre 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 130 N° 4 (Octobre 2008) . - 10 p. Titre : Running torque of ball bearings with polymer lubricant (running torque formulas of deep groove ball bearings under axial loads) Type de document : texte imprimé Auteurs : Masayuki Kanatsu, Auteur ; Ohta, Hiroyuki, Auteur Article en page(s) : 10 p. Note générale : Tribology Langues : Anglais (eng) Mots-clés : Torque  Friction  Stress  Release  agents  (Additives)  Bearings  Ball  bearings  Mineral  oil  Rolling  friction  Shearing  Electrical  resistance Résumé : A running torque analysis was performed on axially loaded deep groove ball bearings lubricated with a polymer lubricant. The analysis included a Type I and a Type II bearing. The Type I bearing has a stamped steel riveted cage with its cavity packed with the polymer lubricant. The ball surface, except for the contact points of the ball and the raceways, was covered with the polymer lubricant. The Type II bearing had the polymer lubricant packed only on the riveted parts of the cage; the balls were not covered with the polymer lubricant. The analysis was applied to a 6206 deep groove ball bearing axially loaded in a range typical of preloads applied in actual application to this size bearing to establish bearing tare torque. The results were compared to an available database. The running torque formulas for deep groove ball bearings with polymer lubricant under axial load were proposed as the sums of the running torque caused by the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant, the elastic hysteresis, the differential slip, the spinning friction of the balls, the elastohydrodynamic lubrication (EHL) viscous rolling resistance, and the friction between the balls and the polymer lubricant (or the cage). The effects of the sources of the running torque were investigated. In the case of the Type I bearing, the running torque caused by the friction between the balls and the polymer lubricant, the EHL viscous rolling resistance, and the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant significantly affect the running torque. In the case of the Type II Bearing, the running torque caused by the EHL viscous rolling resistance and the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant significantly affect the running torque. A reasonable correlation exists between the analysis and the database. However, the analysis needs to be further validated with bearing data from different size deep groove ball bearings run under varying loads and speeds. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleid=1468113 [article] Running torque of ball bearings with polymer lubricant (running torque formulas of deep groove ball bearings under axial loads) [texte imprimé] / Masayuki Kanatsu, Auteur ; Ohta, Hiroyuki, Auteur . - 10 p. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 130 N° 4 (Octobre 2008) . - 10 p. Mots-clés : Torque  Friction  Stress  Release  agents  (Additives)  Bearings  Ball  bearings  Mineral  oil  Rolling  friction  Shearing  Electrical  resistance Résumé : A running torque analysis was performed on axially loaded deep groove ball bearings lubricated with a polymer lubricant. The analysis included a Type I and a Type II bearing. The Type I bearing has a stamped steel riveted cage with its cavity packed with the polymer lubricant. The ball surface, except for the contact points of the ball and the raceways, was covered with the polymer lubricant. The Type II bearing had the polymer lubricant packed only on the riveted parts of the cage; the balls were not covered with the polymer lubricant. The analysis was applied to a 6206 deep groove ball bearing axially loaded in a range typical of preloads applied in actual application to this size bearing to establish bearing tare torque. The results were compared to an available database. The running torque formulas for deep groove ball bearings with polymer lubricant under axial load were proposed as the sums of the running torque caused by the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant, the elastic hysteresis, the differential slip, the spinning friction of the balls, the elastohydrodynamic lubrication (EHL) viscous rolling resistance, and the friction between the balls and the polymer lubricant (or the cage). The effects of the sources of the running torque were investigated. In the case of the Type I bearing, the running torque caused by the friction between the balls and the polymer lubricant, the EHL viscous rolling resistance, and the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant significantly affect the running torque. In the case of the Type II Bearing, the running torque caused by the EHL viscous rolling resistance and the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant significantly affect the running torque. A reasonable correlation exists between the analysis and the database. However, the analysis needs to be further validated with bearing data from different size deep groove ball bearings run under varying loads and speeds. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleid=1468113

Vertical stiffnesses of preloaded linear guideway type ball bearings incorporating the flexibility of the carriage and rail / Ohta, Hiroyuki in Transactions of the ASME . Journal of tribology, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Titre : Vertical stiffnesses of preloaded linear guideway type ball bearings incorporating the flexibility of the carriage and rail Type de document : texte imprimé Auteurs : Ohta, Hiroyuki, Auteur ; Tanaka, Keisuke, Auteur Article en page(s) : 09 p. Langues : Anglais (eng) Mots-clés : Linear  guideway  Ball  bearings  Stiffness  Carriage  Rail  Flexibility Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This article deals with the vertical stiffnesses of preloaded linear guideway type ball bearings (linear bearings) incorporating the flexibility of the carriage and rail. First the vertical stiffnesses of light and medium preloaded linear bearings were measured, as well as the outward carriage deformations in the width direction. Compared with the stiffnesses calculated by the conventional rigid model (assuming the carriage and rail are rigid, except for the contact points with the balls), the measured stiffnesses were about 40% less. In preloaded linear bearings under a vertical load, the side faces of the carriage deformed outward. The deformations were minimal at the top, increased toward the bottom, and had a tendency to be greater under either a larger preload or a smaller vertical load. The measured stiffnesses and outward carriage deformations cannot be explained using the conventional rigid model. To overcome these problems with the conventional rigid model, a flexible model (taking into account the flexibility of the carriage and rail) is presented in this article. The flexible model deformations were estimated through finite element (FE) analysis. The Hertzian contacts between the balls and the carriage or rail also were considered. With relative errors of 9–21%, the calculated stiffnesses using the flexible model more closely matched the measured stiffnesses. Also, the calculated outward carriage deformations matched the measured deformations well. Clearly, there is a better match between the calculated results of the flexible model and the measurements than with the conventional rigid model. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...] [article] Vertical stiffnesses of preloaded linear guideway type ball bearings incorporating the flexibility of the carriage and rail [texte imprimé] / Ohta, Hiroyuki, Auteur ; Tanaka, Keisuke, Auteur . - 09 p. Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Mots-clés : Linear  guideway  Ball  bearings  Stiffness  Carriage  Rail  Flexibility Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This article deals with the vertical stiffnesses of preloaded linear guideway type ball bearings (linear bearings) incorporating the flexibility of the carriage and rail. First the vertical stiffnesses of light and medium preloaded linear bearings were measured, as well as the outward carriage deformations in the width direction. Compared with the stiffnesses calculated by the conventional rigid model (assuming the carriage and rail are rigid, except for the contact points with the balls), the measured stiffnesses were about 40% less. In preloaded linear bearings under a vertical load, the side faces of the carriage deformed outward. The deformations were minimal at the top, increased toward the bottom, and had a tendency to be greater under either a larger preload or a smaller vertical load. The measured stiffnesses and outward carriage deformations cannot be explained using the conventional rigid model. To overcome these problems with the conventional rigid model, a flexible model (taking into account the flexibility of the carriage and rail) is presented in this article. The flexible model deformations were estimated through finite element (FE) analysis. The Hertzian contacts between the balls and the carriage or rail also were considered. With relative errors of 9–21%, the calculated stiffnesses using the flexible model more closely matched the measured stiffnesses. Also, the calculated outward carriage deformations matched the measured deformations well. Clearly, there is a better match between the calculated results of the flexible model and the measurements than with the conventional rigid model. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...]

Vibration and acoustic emission of linear-guideway type recirculating ball bearings with a millimeter-sized artificial defect in the carriage / Ohta, Hiroyuki in Transactions of the ASME . Journal of tribology, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 132 N° 1 (Janvier 2010) . - pp. 1-6 Titre : Vibration and acoustic emission of linear-guideway type recirculating ball bearings with a millimeter-sized artificial defect in the carriage Type de document : texte imprimé Auteurs : Ohta, Hiroyuki, Auteur ; Matsuura, Kazuya, Auteur ; Kato, Soichiro, Auteur ; Igarashi, Yutaka Article en page(s) : pp. 1-6 Note générale : Tribology Langues : Anglais (eng) Mots-clés : Minear-guideway  Recirculating  linear  ball  bearing  Carriage  Defect  Vibration  Acoustic  emission Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper deals with vibrations and acoustic emissions (AEs) of linear-guideway type recirculating ball bearings with a millimeter-sized artificial defect in the carriage. The vibration and AE of one normal bearing without a defect (Type N), and six defective bearings (Types D1–D6) were measured using a linear velocity of 1 m/s. The defects in the bearings range from 1.87 mm to 6.77 mm in length, 2.45 mm to 3.80 mm in width, and 23.3 µm to 68.0 µm in depth. The experimental results show that the pulse amplitudes of the vibrations and AE (both the peak-to-peak and RMS values) of the defective bearings have a tendency to be greater than those of the normal bearing. Both the measured vibration and AE components over 30 kHz increased in the carriages with defects. To explain these increases in the defective bearings, a collision model with balls and one defect in the carriage is presented. That collision model shows that the increases in both the vibrations and AE of the defective bearings are caused by increases in the defect angle. A reasonable correlation exists between the presented collision model and the measured vibrations or AE of the defective bearings. DEWEY : 621.5 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013200 [...] [article] Vibration and acoustic emission of linear-guideway type recirculating ball bearings with a millimeter-sized artificial defect in the carriage [texte imprimé] / Ohta, Hiroyuki, Auteur ; Matsuura, Kazuya, Auteur ; Kato, Soichiro, Auteur ; Igarashi, Yutaka . - pp. 1-6. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 132 N° 1 (Janvier 2010) . - pp. 1-6 Mots-clés : Minear-guideway  Recirculating  linear  ball  bearing  Carriage  Defect  Vibration  Acoustic  emission Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper deals with vibrations and acoustic emissions (AEs) of linear-guideway type recirculating ball bearings with a millimeter-sized artificial defect in the carriage. The vibration and AE of one normal bearing without a defect (Type N), and six defective bearings (Types D1–D6) were measured using a linear velocity of 1 m/s. The defects in the bearings range from 1.87 mm to 6.77 mm in length, 2.45 mm to 3.80 mm in width, and 23.3 µm to 68.0 µm in depth. The experimental results show that the pulse amplitudes of the vibrations and AE (both the peak-to-peak and RMS values) of the defective bearings have a tendency to be greater than those of the normal bearing. Both the measured vibration and AE components over 30 kHz increased in the carriages with defects. To explain these increases in the defective bearings, a collision model with balls and one defect in the carriage is presented. That collision model shows that the increases in both the vibrations and AE of the defective bearings are caused by increases in the defect angle. A reasonable correlation exists between the presented collision model and the measured vibrations or AE of the defective bearings. DEWEY : 621.5 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013200 [...]