False brinelling: Difference between revisions
Content deleted Content added
WindWind5000 (talk | contribs) No edit summary |
WindWind5000 (talk | contribs) m Footnotes are improved. More internal links. |
||
| Line 3: | Line 3: | ||
'''False brinelling''' is a [[Bearing (mechanical)|bearing]] damage caused by [[fretting]], with or without [[corrosion]]<ref>{{Cite web|url=https://www.researchgate.net/publication/316543220_Time-dependent_analyses_of_wear_in_oscillating_bearing_applications|title=Time-dependent analyses of wear in oscillating bearing applications (PDF Download Available)|last=Schwack|first=Fabian|last2=|date=|website=ResearchGate|language=en|archive-url=|archive-date=|dead-url=|access-date=2017-06-27}}</ref>, that causes imprints that look similar to [[brinelling]], but are caused by a different mechanism. False brinelling may occur in bearings which act under small oscillations<ref>{{Cite web|url=https://www.researchgate.net/publication/309585771_Service_Life_of_Blade_Bearings_-_Problems_Faced_in_Service_Life_Estimation_of_Blade_Bearings|title=Service Life of Blade Bearings - Problems Faced in Service Life Estimation of Blade Bearings|last=Schwack|first=Fabian|last2=Poll|first2=Gerhard|authorlink2=|date=|website=ResearchGate|language=en|archive-url=|archive-date=|dead-url=|access-date=2017-06-27}}</ref> or vibrations<ref>{{Cite journal|last=Pittroff|first=Hans|date=1965-09-01|title=Fretting Corrosion Caused by Vibration With Rolling Bearings Stationary|url=http://dx.doi.org/10.1115/1.3650657|journal=Journal of Basic Engineering|volume=87|issue=3|pages=713–723|doi=10.1115/1.3650657|issn=0098-2202}}</ref>. |
'''False brinelling''' is a [[Bearing (mechanical)|bearing]] damage caused by [[fretting]], with or without [[corrosion]]<ref>{{Cite web|url=https://www.researchgate.net/publication/316543220_Time-dependent_analyses_of_wear_in_oscillating_bearing_applications|title=Time-dependent analyses of wear in oscillating bearing applications (PDF Download Available)|last=Schwack|first=Fabian|last2=|date=|website=ResearchGate|language=en|archive-url=|archive-date=|dead-url=|access-date=2017-06-27}}</ref>, that causes imprints that look similar to [[brinelling]], but are caused by a different mechanism. False brinelling may occur in bearings which act under small oscillations<ref>{{Cite web|url=https://www.researchgate.net/publication/309585771_Service_Life_of_Blade_Bearings_-_Problems_Faced_in_Service_Life_Estimation_of_Blade_Bearings|title=Service Life of Blade Bearings - Problems Faced in Service Life Estimation of Blade Bearings|last=Schwack|first=Fabian|last2=Poll|first2=Gerhard|authorlink2=|date=|website=ResearchGate|language=en|archive-url=|archive-date=|dead-url=|access-date=2017-06-27}}</ref> or vibrations<ref>{{Cite journal|last=Pittroff|first=Hans|date=1965-09-01|title=Fretting Corrosion Caused by Vibration With Rolling Bearings Stationary|url=http://dx.doi.org/10.1115/1.3650657|journal=Journal of Basic Engineering|volume=87|issue=3|pages=713–723|doi=10.1115/1.3650657|issn=0098-2202}}</ref>. |
||
The basic cause of false brinelling is that the design of the bearing does not have a method for redistribution of [[lubricant]] without large rotational movement of all bearing surfaces in the raceway. Lubricant is pushed out of a loaded region during small oscillatory movements and vibration where the bearings surfaces repeatedly do not move very far.<ref>{{ |
The basic cause of false brinelling is that the design of the bearing does not have a method for redistribution of [[lubricant]] without large rotational movement of all bearing surfaces in the raceway. Lubricant is pushed out of a loaded region during small oscillatory movements and vibration where the bearings surfaces repeatedly do not move very far.<ref>{{Cite book|url=https://link.springer.com/chapter/10.1007/978-3-642-03653-8_16|title=Advanced Tribology|last=Feng|first=Chen|last2=Maruyama|first2=Taisuke|last3=Saito|first3=Tsuyoshi|date=2009|publisher=Springer, Berlin, Heidelberg|pages=42–43|language=en|doi=10.1007/978-3-642-03653-8_16}}</ref> Without lubricant, wear is increased when the small oscillatory movements occur again. It is possible for the resulting [[wear]] debris to [[Oxide|oxidize]] and form an abrasive compound which further accelerates wear. |
||
==Mechanism of action== |
==Mechanism of action== |
||
In normal operation, a rolling-element [[Bearing (mechanical)|bearing]] has the rollers and races separated by a thin layer of lubricant such as [[grease (lubricant)|grease]] or [[oil]]. Although these lubricants normally appear liquid (not solid), under high pressure they act as solids and keep the bearing and race from touching<ref>{{ |
In normal operation, a rolling-element [[Bearing (mechanical)|bearing]] has the rollers and races separated by a thin layer of lubricant such as [[grease (lubricant)|grease]] or [[oil|oil.]]<ref>{{Cite journal|last=Maruyama|first=Taisuke|last2=Saitoh|first2=Tsuyoshi|last3=Yokouchi|first3=Atsushi|date=2017-05-04|title=Differences in Mechanisms for Fretting Wear Reduction between Oil and Grease Lubrication|url=http://dx.doi.org/10.1080/10402004.2016.1180469|journal=Tribology Transactions|volume=60|issue=3|pages=497–505|doi=10.1080/10402004.2016.1180469|issn=1040-2004}}</ref> Although these lubricants normally appear liquid (not solid), under high pressure they act as solids and keep the bearing and race from touching.<ref>{{Cite web|url=https://de.scribd.com/document/122449861/Fretting-Corrosion-or-False-Brinelling|title=Fretting Corrosion or False Brinelling {{!}} Wear {{!}} Surface Science|last=Godfrey|first=Douglas|date=|website=Scribd|language=en|archive-url=|archive-date=|dead-url=|access-date=2017-06-27}}</ref><ref>{{Cite web|url=https://www.researchgate.net/publication/286233368_Another_perspective_False_brinelling_and_fretting_corrosion|title=Another perspective: False brinelling and fretting corrosion (PDF Download Available)|last=Errichello|first=Robert|date=|website=ResearchGate|language=en|archive-url=|archive-date=|dead-url=|access-date=2017-06-27}}</ref> |
||
If the lubricant is removed |
If the lubricant is removed, the bearings and races can touch directly. While bearings and races appear smooth to the eye, they are microscopically rough. Thus, high points of each surface can touch, but "valleys" do not. The bearing load is thus spread over much less area increasing the contact [[Stress (mechanics)|stress]]<ref>{{Cite journal|last=Tonazzi|first=D.|last2=Komba|first2=E. Houara|last3=Massi|first3=F.|last4=Le Jeune|first4=G.|last5=Coudert|first5=J. B.|last6=Maheo|first6=Y.|last7=Berthier|first7=Y.|date=2017-04-15|title=Numerical analysis of contact stress and strain distributions for greased and ungreased high loaded oscillating bearings|url=http://www.sciencedirect.com/science/article/pii/S0043164816308729|journal=Wear|series=21st International Conference on Wear of Materials|volume=376–377, Part B|pages=1164–1175|doi=10.1016/j.wear.2016.11.037}}</ref>, causing pieces of each surface to break off or to become pressure-welded then break off when the bearing rolls on. |
||
The broken-off pieces are also called ''wear debris''. Wear debris is bad because it is relatively large compared to the surrounding surface finish and thus creates more regions of high contact stress. Worse, the steel in ordinary bearings can oxidize (rust), producing a more abrasive compound which accelerates wear. |
The broken-off pieces are also called ''wear debris''. Wear debris is bad because it is relatively large compared to the surrounding surface finish and thus creates more regions of high contact stress. Worse, the steel in ordinary bearings can oxidize ([[rust]])<ref>{{Cite journal|last=Tomlinson|first=G. A.|date=1927-07-01|title=The Rusting of Steel Surfaces in Contact|url=http://rspa.royalsocietypublishing.org/content/115/771/472|journal=Proceedings of the Royal Society of London A: Mathematical, Physical and Engineering Sciences|language=en|volume=115|issue=771|pages=472–483|doi=10.1098/rspa.1927.0104|issn=1364-5021}}</ref>, producing a more abrasive compound which accelerates wear. |
||
[[File:False brinelling schwack.png|thumb|Microscopy of an false brinelling damaged bearing raceway]] |
[[File:False brinelling schwack.png|thumb|Microscopy of an false brinelling damaged bearing raceway]] |
||
==Examples== |
==Examples== |
||
False brinelling was first mentioned by Almen in 1937<ref>{{cite journal|last1=Almen|first1=J.O.|title=Lubricants and False Brinelling of Ball and Roller Bearings|journal=Mechanical Engineering|date=1937|volume=59|issue=6|pages=415-422}}</ref>. Almen found that wheel bearings were damaged before they were used by customers. Furthermore, he found that the bearings were more damaged for long-distance shipping of the cars and that the season of shipping also had an influence. The reason for the damaged bearings were micro-oscillations<ref>{{cite journal|last1=Pittroff|first1=Hans|title=Fretting Corrosion Caused by Vibration With Rolling Bearings Stationary|journal=Journal of Basic Engineering|date=1965|volume=87|issue=3|page=713-723}}</ref> which occurred due to the shipping. Because the damage has a similar look to brinelling, it was called false brinelling.<ref>{{ |
False brinelling was first mentioned by Almen in 1937<ref>{{cite journal|last1=Almen|first1=J.O.|title=Lubricants and False Brinelling of Ball and Roller Bearings|journal=Mechanical Engineering|date=1937|volume=59|issue=6|pages=415-422}}</ref>. Almen found that wheel bearings were damaged before they were used by customers. Furthermore, he found that the bearings were more damaged for long-distance shipping of the cars and that the season of shipping also had an influence. The reason for the damaged bearings were micro-oscillations<ref>{{cite journal|last1=Pittroff|first1=Hans|title=Fretting Corrosion Caused by Vibration With Rolling Bearings Stationary|journal=Journal of Basic Engineering|date=1965|volume=87|issue=3|page=713-723}}</ref> which occurred due to the shipping. Because the damage has a similar look to brinelling, it was called false brinelling.<ref>{{Cite web|url=https://www.researchgate.net/publication/309585771_Service_Life_of_Blade_Bearings_-_Problems_Faced_in_Service_Life_Estimation_of_Blade_Bearings|title=Service Life of Blade Bearings - Problems Faced in Service Life Estimation of Blade Bearings|last=Schwack|first=Fabian|last2=Poll|first2=Gerhard|date=|website=ResearchGate|language=en|archive-url=|archive-date=|dead-url=|access-date=2017-06-27}}</ref> |
||
Although the auto-delivery problem has been solved, there are many modern examples. For example, [[Electrical generator|generator]]s or [[pump]]s may fail or need service, so it is common to have a nearby spare unit which is left off most of the time but brought into service when needed. Surprisingly, however, vibration from the operating unit can cause bearing failure in the unit which is switched off. When that unit is turned on, the bearings may be noisy due to damage, and may fail completely within a few days or weeks<ref>{{cite journal|last1=Schwack|first1=Fabian|title=Comparison of Life Calculations for Oscillating Bearings Considering Individual Pitch Control in Wind Turbines|journal=Journal of Physics - Conference Series|date=2016|issue=753|pages=11|doi=10.1088/1742-6596/753/11/112013}}</ref> even though the unit and its bearings are otherwise new. Common solutions include: keeping the spare unit at a distance from the one which is on and vibrating; manually rotating shafts of the spare units on a regular (for example, weekly) basis; or regularly switching between the units so that both are in regular (for example, weekly) operation. |
Although the auto-delivery problem has been solved, there are many modern examples. For example, [[Electrical generator|generator]]s or [[pump]]s may fail or need service, so it is common to have a nearby spare unit which is left off most of the time but brought into service when needed. Surprisingly, however, vibration from the operating unit can cause bearing failure in the unit which is switched off. When that unit is turned on, the bearings may be noisy due to damage, and may fail completely within a few days or weeks<ref>{{cite journal|last1=Schwack|first1=Fabian|title=Comparison of Life Calculations for Oscillating Bearings Considering Individual Pitch Control in Wind Turbines|journal=Journal of Physics - Conference Series|date=2016|issue=753|pages=11|doi=10.1088/1742-6596/753/11/112013}}</ref><ref>{{Cite web|url=https://www.tib.eu/en/search/id/tema:TEMA20130803793/False-brinelling-standstill-marks-on-roller-bearings/?tx_tibsearch_search%5Bsearchspace%5D=tn|title=False brinelling standstill marks on roller bearings - Technische Informationsbibliothek (TIB)|website=www.tib.eu|language=en|access-date=2017-06-27}}</ref> even though the unit and its bearings are otherwise new. Common solutions include: keeping the spare unit at a distance from the one which is on and vibrating; manually rotating shafts of the spare units on a regular (for example, weekly) basis; or regularly switching between the units so that both are in regular (for example, weekly) operation. |
||
Until recently, bicycle [[Headset (bicycle part)|headsets]] tended to suffer from false brinelling in the "straight ahead" steering position, due to small movements caused by flexing of the fork. Good modern headsets incorporate a plain bearing to accommodate this flexing, leaving the ball race to provide pure rotational movement. |
Until recently, bicycle [[Headset (bicycle part)|headsets]] tended to suffer from false brinelling in the "straight ahead" steering position, due to small movements caused by flexing of the fork. Good modern headsets incorporate a plain bearing to accommodate this flexing, leaving the ball race to provide pure rotational movement. |
||
Revision as of 10:21, 27 June 2017
False brinelling is a bearing damage caused by fretting, with or without corrosion[1], that causes imprints that look similar to brinelling, but are caused by a different mechanism. False brinelling may occur in bearings which act under small oscillations[2] or vibrations[3].
The basic cause of false brinelling is that the design of the bearing does not have a method for redistribution of lubricant without large rotational movement of all bearing surfaces in the raceway. Lubricant is pushed out of a loaded region during small oscillatory movements and vibration where the bearings surfaces repeatedly do not move very far.[4] Without lubricant, wear is increased when the small oscillatory movements occur again. It is possible for the resulting wear debris to oxidize and form an abrasive compound which further accelerates wear.
Mechanism of action
In normal operation, a rolling-element bearing has the rollers and races separated by a thin layer of lubricant such as grease or oil.[5] Although these lubricants normally appear liquid (not solid), under high pressure they act as solids and keep the bearing and race from touching.[6][7]
If the lubricant is removed, the bearings and races can touch directly. While bearings and races appear smooth to the eye, they are microscopically rough. Thus, high points of each surface can touch, but "valleys" do not. The bearing load is thus spread over much less area increasing the contact stress[8], causing pieces of each surface to break off or to become pressure-welded then break off when the bearing rolls on.
The broken-off pieces are also called wear debris. Wear debris is bad because it is relatively large compared to the surrounding surface finish and thus creates more regions of high contact stress. Worse, the steel in ordinary bearings can oxidize (rust)[9], producing a more abrasive compound which accelerates wear.
Examples
False brinelling was first mentioned by Almen in 1937[10]. Almen found that wheel bearings were damaged before they were used by customers. Furthermore, he found that the bearings were more damaged for long-distance shipping of the cars and that the season of shipping also had an influence. The reason for the damaged bearings were micro-oscillations[11] which occurred due to the shipping. Because the damage has a similar look to brinelling, it was called false brinelling.[12]
Although the auto-delivery problem has been solved, there are many modern examples. For example, generators or pumps may fail or need service, so it is common to have a nearby spare unit which is left off most of the time but brought into service when needed. Surprisingly, however, vibration from the operating unit can cause bearing failure in the unit which is switched off. When that unit is turned on, the bearings may be noisy due to damage, and may fail completely within a few days or weeks[13][14] even though the unit and its bearings are otherwise new. Common solutions include: keeping the spare unit at a distance from the one which is on and vibrating; manually rotating shafts of the spare units on a regular (for example, weekly) basis; or regularly switching between the units so that both are in regular (for example, weekly) operation.
Until recently, bicycle headsets tended to suffer from false brinelling in the "straight ahead" steering position, due to small movements caused by flexing of the fork. Good modern headsets incorporate a plain bearing to accommodate this flexing, leaving the ball race to provide pure rotational movement.
Bearings of modern wind turbines are often affected by false brinelling. Especially the pitch bearing[15], which is used under oscillation, shows often false brinelling damages.[16]
External links
- Emerson Bearing picture of false Brinelling
- Precision Spindle explanation of false Brinelling
- MRO Today on rotating spares
- US Motors service bulletin case study, explanation, and pictures (PDF)
- ^ Schwack, Fabian. "Time-dependent analyses of wear in oscillating bearing applications (PDF Download Available)". ResearchGate. Retrieved 2017-06-27.
{{cite web}}: Cite has empty unknown parameter:|dead-url=(help) - ^ Schwack, Fabian; Poll, Gerhard. "Service Life of Blade Bearings - Problems Faced in Service Life Estimation of Blade Bearings". ResearchGate. Retrieved 2017-06-27.
{{cite web}}: Cite has empty unknown parameter:|dead-url=(help) - ^ Pittroff, Hans (1965-09-01). "Fretting Corrosion Caused by Vibration With Rolling Bearings Stationary". Journal of Basic Engineering. 87 (3): 713–723. doi:10.1115/1.3650657. ISSN 0098-2202.
- ^ Feng, Chen; Maruyama, Taisuke; Saito, Tsuyoshi (2009). Advanced Tribology. Springer, Berlin, Heidelberg. pp. 42–43. doi:10.1007/978-3-642-03653-8_16.
- ^ Maruyama, Taisuke; Saitoh, Tsuyoshi; Yokouchi, Atsushi (2017-05-04). "Differences in Mechanisms for Fretting Wear Reduction between Oil and Grease Lubrication". Tribology Transactions. 60 (3): 497–505. doi:10.1080/10402004.2016.1180469. ISSN 1040-2004.
- ^ Godfrey, Douglas. "Fretting Corrosion or False Brinelling | Wear | Surface Science". Scribd. Retrieved 2017-06-27.
{{cite web}}: Cite has empty unknown parameter:|dead-url=(help) - ^ Errichello, Robert. "Another perspective: False brinelling and fretting corrosion (PDF Download Available)". ResearchGate. Retrieved 2017-06-27.
{{cite web}}: Cite has empty unknown parameter:|dead-url=(help) - ^ Tonazzi, D.; Komba, E. Houara; Massi, F.; Le Jeune, G.; Coudert, J. B.; Maheo, Y.; Berthier, Y. (2017-04-15). "Numerical analysis of contact stress and strain distributions for greased and ungreased high loaded oscillating bearings". Wear. 21st International Conference on Wear of Materials. 376–377, Part B: 1164–1175. doi:10.1016/j.wear.2016.11.037.
- ^ Tomlinson, G. A. (1927-07-01). "The Rusting of Steel Surfaces in Contact". Proceedings of the Royal Society of London A: Mathematical, Physical and Engineering Sciences. 115 (771): 472–483. doi:10.1098/rspa.1927.0104. ISSN 1364-5021.
- ^ Almen, J.O. (1937). "Lubricants and False Brinelling of Ball and Roller Bearings". Mechanical Engineering. 59 (6): 415–422.
- ^ Pittroff, Hans (1965). "Fretting Corrosion Caused by Vibration With Rolling Bearings Stationary". Journal of Basic Engineering. 87 (3): 713-723.
- ^ Schwack, Fabian; Poll, Gerhard. "Service Life of Blade Bearings - Problems Faced in Service Life Estimation of Blade Bearings". ResearchGate. Retrieved 2017-06-27.
{{cite web}}: Cite has empty unknown parameter:|dead-url=(help) - ^ Schwack, Fabian (2016). "Comparison of Life Calculations for Oscillating Bearings Considering Individual Pitch Control in Wind Turbines". Journal of Physics - Conference Series (753): 11. doi:10.1088/1742-6596/753/11/112013.
- ^ "False brinelling standstill marks on roller bearings - Technische Informationsbibliothek (TIB)". www.tib.eu. Retrieved 2017-06-27.
- ^ Stammler, Matthias (März 2015). "Blade bearings: Damage mechanisms and test strategies". CWD 2015: 371–379.
{{cite journal}}: Check date values in:|date=(help) - ^ Schwack, Fabian (2017). "Time-depending analyses of wear in oscillating bearings". STLE (72th).