Temat: micro-bearing - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Friction forces and friction coefficient in slide parabolic micro-bearing with consideration of the adhesion force
Autorzy:: Miszczyk, Miszczak, A.
Czaban, A.
Powiązania:: https://bibliotekanauki.pl/articles/244068.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: adsorption
adhesion
capillary forces
micro-bearing lubrication
Opis:: Micro-bearings have many applications in computer devices, such as CPU fans or hard disc drives. So far, rolling bearings and slide bearings have been used,for example micro-bearing with smooth Journal and sleeve surface, which is known as FDB - Fluid Dynamic Bearing. Actually, latter versions of micro-bearings are being launched to the market: Ex-FDB - Extra Fluid Dynamic Bearing. This type of bearings was fabricated by putting some micro-grooves filled with oil on its interna! surfaces. Ex-FDB's are characterized by reduced level of generated noise and guarantee long failure-free fan life, reaching 120 000 hours. In this paper we present our numerical calculations of the friction force and the friction coefficient in the parabolic micro-bearing. Micro-bearing gap height is very low, often less then l micrometer, therefore capillarity and adhesion forces cause an increase of oil viscosity near the Journal and sleeve surfaces. Due to this fact a value of hydrodynamic pressure in micro-bearing gap also increases, what results in observed changes of capacity, friction forces and friction coefficient values. The influence of adhesion and capillarity on friction force and friction coefficient of oil in micro-bearing hasn't been considered from analytical point of view so far. This paper presents numerical results of computed values of friction forces and friction coefficient for parabolic micro-bearing in comparison to values for classical parabolic bearing.
Źródło:: Journal of KONES; 2010, 17, 3; 293-299
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Adhesion and capilarity in micro-bearing lubrication
Autorzy:: Wierzcholski, K.
Miszczak, A.
Powiązania:: https://bibliotekanauki.pl/articles/245795.pdf
Data publikacji:: 2009
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: adsorption
adhesion
capillary forces
micro-bearing lubrication
Opis:: Present paper shows the some main phenomena which have important influence on the micro-bearing operating parameters. To above mentioned phenomena belong: adhesion forces, adsorption forces, capillary forces, elastic and hyperelastic deformations of cooperating micro-bearing surfaces, Van-der Waals electrostatic forces on the micro-bearing surfaces. Because the height of super thin micro-bearing gap is very small often smaller than l micrometer, hence the adhesion forces and capillary forces arising in micro-bearing gap, provoke the oil dynamic viscosity changes. This fact leads to the hydrodynamic pressure and bearing carrying capacity changes. The performed research play off the main role of mechanical micro-deformations of cooperating micro-bearing surfaces on non-Newtonian oil dynamic viscosity and here are indicated the influence of capillary force on adhesion forces in micro-scale. The micro-deformations of the micro-bearing gap height are effecting the changes of oil flow velocity in the gap, this fact leads to the share rate changes and therefore we obtain changes of apparent viscosity of the non-Newtonian oil.
Źródło:: Journal of KONES; 2009, 16, 3; 489-495
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Adhesion influence on the oil velocity and friction forces in hyperbolic microbearing gap
Autorzy:: Wierzcholski, K.
Miszczak, A.
Powiązania:: https://bibliotekanauki.pl/articles/247611.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: adhesion forces
hyperbolic micro-bearing
oil velocity
hydrodynamic pressure
Opis:: In this paper are presented the influences of the adhesion forces occurring in hyperbolic micro contact on the oil velocity and friction forces in hyperbolic micro bearing gap. Here are elaborated the dependences between adhesive forces and oil dynamic viscosity in super thin boundary layer and influences of adhesive forces on the oil velocities and friction forces in micro- and nano-scale arising between two cooperating hyperbolic surfaces in micro-bearings. Oil dynamic viscosity is a sum of classical viscosity and viscosity caused by adhesion and cohesion forces. In hyperbolic micro-bearing the influence of adhesive forces on friction forces is visible not only in friction forces caused by the hydrodynamic pressure but also in friction forces caused by the oil flow velocity. The pressure distributions and capacity values in machine hyperbolic slide micro-bearings are determined in the lubrication region which is defined on the micro-bearing surfaces. Numerical calculations are performed in Mathcad 14 Professional Program implemented by virtue of difference method. In this paper are derived the formulas for velocity components, pressure distributions, friction forces and friction coefficients in hyperbolic coordinates and at the same time the adhesion forces are considered. Up to now the influence of adhesion forces on oil velocity and friction force changes in hyperbolic micro-bearing gap were not considered in analytical way. Present paper elaborat es the preliminary assumptions of hydrodynamic theory of lubrication for hyperbolic micro-bearing in the case if during the lubrication the adhesion forces are taken into account.
Źródło:: Journal of KONES; 2010, 17, 3; 483-489
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Unified summation equations and their applications in tribology wear process
Autorzy:: Wierzcholski, K.
Powiązania:: https://bibliotekanauki.pl/articles/200950.pdf
Data publikacji:: 2013
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: unified operator of summation
summation equation
micro-bearing wear
Opis:: This paper presents some applications of summation equations with regard to the calculation prognosis of micro-bearing wear parameters. Summation equations are presented in a new form of difference and recurrence equations where the unknown micro-bearing wear function occurs as the argument of the reciprocal unified operator of summation (UOS). In this paper the properties of the UOS and reciprocal UOS as well as the unitary translation operator (UTO) are defined and applied to a micro-bearing wear determination. The approach of both dual and interaction between summation and recurrence equations and micro-bearing wear determination, makes this paper unique.
Źródło:: Bulletin of the Polish Academy of Sciences. Technical Sciences; 2013, 61, 2; 405-417
0239-7528
Pojawia się w:: Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Tribological systems of surfaces with frictional resistance reduction
Autorzy:: Wierzcholski, K.
Miszczak, A.
Powiązania:: https://bibliotekanauki.pl/articles/247630.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: nano-ridges
groove geometry
reduced friction
micro-bearing
shark skin
Opis:: In this paper are assumed micro-ridges and micro-grooves on the Journal and bearing sleeve surfaces. Friction on the boundary layer of the body moving in the oil at high Reynolds numbers may be decreased due to such asculpturing of the surface. The grooved scale of the shark skin is an example of such tribological systems. There size ranges of the grooves are from 200 jum to 400/jm. The surface of the each scale contains parallel groove between so-called ribbed directed almost parallel to the longitudinal body axis. An explanation of the shark skin effect has been proposed recently for the micro-bearing surfaces shapes execution. In the boundary layer, not only longitudinal micro-turbulence but also cross-directed micro-turbulence occurs. The longitudinal grooves of the shark and bearing surface prevent the appearance of the cross-directed micro-turbulences. Forces of the streaming oil in bearing or micro-bearing gap act on the bearing surface in two different ways. On one side, the oil generates the pressure directed normally to the surface of the Journal surface and is responsible for inertiaforces. On the other side, friction or shearing force acts tangentially to the bearing surface. The resulting force depends on the geometry of the body, its relative dimensions to the oilflow and on such characteristics of the oil as its density, viscosity and velocity.
Źródło:: Journal of KONES; 2010, 17, 3; 491-496
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Surface topography of non-operated slide journal micro-bearings
Autorzy:: Czaban, A.
Miszczak, A.
Powiązania:: https://bibliotekanauki.pl/articles/242167.pdf
Data publikacji:: 2011
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: atomic force microscope
surface topography
microgrooves
herringbone grooves
micro-bearing
Opis:: In this paper authors present results of measurements of slide journal bearings surface topography measured with an atomic force microscope (AFM). The results of measurements of surface topography were presented in the form of surface topography maps, three-dimensional graphs and some examples of selected cross-sections of investigated surface in the form of profile graphs. Measurements of surface topography were made for journals and sleeves of slide journal micro-bearings from personal computers' hard drives and fans, with the Atomic Force Microscope NT-206 produced in MTM in Minsk, Republic of Belarus. The values of profile roughness parameters Ra and Rq and the distance between maximum peak height and maximum valley depth are presented as well. The application SurfaceXplorerŽ was used for processing and visualization of the data obtained from AFM NT-206, which besides from generating 2D, 3D and profile diagrams, was used to calculate and draw graph of height distribution. Surface pictures of investigated bearings sleeves were made with the optical microscope Zeiss Axiovert 25+. That measurements give information about micro-grooves dimensions and location. On the surfaces of studied micro-bearings some micro-grooves can be found in form of herringbone, with depth about 1.5mi m and width 150/mi m. Received information about micro-grooves geometry will allow to develop proper theory of hydrodynamic lubrication for micro-bearings with micro-grooves. Topography of surfaces of investigated journal micro-bearings will be reconsidered after exploiting them proper amount of time.
Źródło:: Journal of KONES; 2011, 18, 2; 109-115
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Surface topography of operated slide journal micro - bearings used in computer fans
Autorzy:: Miszczak, A.
Czaban, A.
Labuda, W.
Powiązania:: https://bibliotekanauki.pl/articles/242980.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: atomic force microscope
surface topography
microgrooves
herringbone grooves
micro-bearing
Opis:: In this paper authors present results of measurements of slide journal bearings surface topography measured with a profilometer and an atomic force microscope (AFM). Surface topography of investigated bearings (i.e. journals and sleeves) was measured using the Hommeltester T8000- R60 profilometer. The results of these measurements give information about micro-grooves dimensions and location. Measurements of surface topography were made for journals and sleeves of slide journal micro-bearings from personal computers fans, with the Atomic Force Microscope NT-206 produced in MTM in Minsk, Republic of Belarus. The results of measurements of surface topography were presented in the form of surface topography maps, threedimensional graphs and some examples of selected cross-sections of investigated surfaces in the form of profile graphs. The values of profile roughness parameters Ra and Rq and the distance between maximum peak height and maximum valley depth are presented as well. The application SurfaceXplorer registered trademark was used for processing and visualization of the data obtained from AFM NT-206, which besides from generating 2D, 3D and profile diagrams, was used to calculate and draw graphs of height distribution. In this research authors used two identical sets of micro-bearings. The investigated bearings are: a) Kama Flow SP0825FDB12H fan with grooved surface of bearing sleeve, b) Xilence Case fan which sleeve surface was without grooves. First set of that micro-bearings functioned for a year at rated RPM continuously (i.e. 24 hours a day). Second set of the same micro-bearings also functioned for a year at rated RPM, but in intermittent mode (i.e. 15 minutes on, 15 minutes off). On the surfaces of studied micro-bearings some microgrooves can be found in form of herringbone, with depth about 1-2..m and width 100-150..m. Received information about microgrooves geometry will help to develop proper theory of hydrodynamic lubrication for micro-bearings with microgrooves and allows determining how the mode of operating affects on the wear of co-operating surfaces.
Źródło:: Journal of KONES; 2012, 19, 4; 457-463
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Intelligent microbearings project with memory of stress-strain history
Autorzy:: Wierzcholski, K.
Miszczak, A.
Kosowski, K.
Powiązania:: https://bibliotekanauki.pl/articles/241991.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: Curvilinear grooved journals
micro bearing in computer disks
capacity memory simulations
Opis:: Taking into account the increasing need of intelligent micro-bearing with memory, this paper presents the optimization, simulation and practical application of operating parameters(load carrying capacity, friction forces, friction coefficient, wear), simulation for hydrodynamic HDD micro-bearing with curvilinear nano-grooved journal profile. One of the reason of such journal profile is that this journal profile contributes to the variation (an increase or decrease) the memory capacity of HDD drive operating on hydrodynamic micro-bearings. Such properties are very important and required in HDD micro-bearings. A general theory of materials with memory is the theory developed by Noll and Koleman. The simple solid body and liquid theory presented in this paper is based on the assumption that stress is defined by a whole deformation history. The changes of micro-bearing superficial surfaces presented in this paper are described by the process of changes of mass of a body system defined by non-classical intelligent oil and bearing material properties. Scientific problems considered in the paper are focused on comparisons and practical applications of tribological processes, which occur during fluid flow around cells lubrication on the nano-surfaces in bio-bearings as well as surfaces of micro-bearings used in micro-mechanisms. Up to now, the dynamic behaviour of HDD spindle system with fluid micro-bearings was considered by Jang at al. [7]. They simulated an increase in the memory capacity by increase in the bearing width and by application herringbone or spiral grooves on the sleeve and journal surfaces of HDD micro-bearings. After proposal contained in this project it is additionally possible to make capacity memory simulations by the various shapes of micro-bearing journal application.
Źródło:: Journal of KONES; 2008, 15, 4; 583-589
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Surface topography of operated slide journal micro - bearings used in HDD
Autorzy:: Miszczak, A.
Powiązania:: https://bibliotekanauki.pl/articles/242978.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: atomic force microscope
surface topography
microgrooves
herringbone grooves
micro bearing in HDD
Opis:: In this paper author present results of measurements of slide journal micro-bearings surface topography measured with an atomic force microscope (AFM). The results of measurements of surface topography were presented in the form of surface topography maps, three-dimensional graphs and some examples of selected cross-sections of investigated surface in the form of profile graphs. Measurements of surface topography were made for journals and sleeves of slide journal micro-bearings from personal computers' hard disc drives, with the Atomic Force Microscope NT-206 produced in MTM in Minsk, Republic of Belarus. In this research author used two identical sets of micro-bearings from 2.5" HDD Samsung HM160HI 5400rpm and 3.5" HDD Seagate Barracuda 7200.10 ST380815AS 7200 rpm hard disc drives. First set of those four microbearings worked for a year at rated RPM continuously (i.e. 24 hours a day). Second set of the same micro-bearings also worked for a year at rated RPM, but in intermittent mode (i.e. 15 minutes on, 15 minutes off). The values of profile roughness parameters Ra and Rq and the distance between maximum peak height and maximum valley depth are presented as well. The application SurfaceXplorer registered trademark was used for processing and visualization of the data obtained from AFM NT-206, which besides from generating 2D, 3D and profile diagrams, was used to calculate and draw graph of height distribution. Surface topography of investigated bearings sleeves was also measured using Hommeltester T8000-R60 profilometer. Those measurements give information about micro-grooves dimensions and location. On the surfaces of studied micro-bearings, some micro-grooves can be found in form of herringbone, with depth about 1.5..m and width 150..m. Received information about micro-grooves geometry will allow developing proper theory of hydrodynamic lubrication for micro-bearings with micro-grooves.
Źródło:: Journal of KONES; 2012, 19, 4; 449-456
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: The viscoelastic lubrication problem of micro-bearing
Problem lepkosprężystego smarowania mikrołożysk
Autorzy:: Wierzcholski, K.
Powiązania:: https://bibliotekanauki.pl/articles/188010.pdf
Data publikacji:: 2010
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: lepkosprężysty olej
walcowe mikrołożysko
prędkość oleju
ciśnienie
siły tarcia
cylindrical micro-bearing
viscoelastic oil
pressure
friction forces
Opis:: In this paper we show the method of solving the lubrication problem occurring in cylindrical micro-bearing gap. Oil velocity components, hydrodynamic pressure and friction forces are derived. We assume complete visco-elastic non-Newtonian lubricant directly near the cooperating surfaces. Viscoelastic oil properties are described by means of Rivlin-Ericksen constitutive relations. Up to now the influences of complete visco-elastic non-Newtonian oil on the pressure and friction forces in cylindrical micro-bearing gap were not considered in analytical way. Paper elaborates analytical formulae for velocity components, pressure distributions, friction forces in cylindrical microbearings.
Ze względu na bardzo małą wysokość szczeliny mikrołożyska, jak również bardzo małą grubość warstwy smarującej w mikrołożyskach ślizgowych mamy do czynienia z wpływem parametrów mechanicznych warstwy wierzchniej na wartość lepkości dynamicznej czynnika smarującego. Ten wpływ ujawnia się poprzez rozbudowane i zmodyfikowane związki konstytutywne o modelu Rivlina-Ericksena. Związki takie wprowadzone do równań ruchu cieczy smarującej wzbogacają te równania o nowe człony, które nie ulegają pominięciu po dokonaniu typowych uproszczeń łożyskowej warstwy granicznej i są związane z liczbami Deboraha, które w rozpatrywanych przypadkach nie są małe. Uwzględnienie tych członów o charakterze lepkosprężystym związanych z wpływem parametrów mechanicznych warstwy wierzchniej na lepkość czynnika smarującego przy rozwiązaniu hydrodynamicznego smarowania mikrołożysk ślizgowych został przedstawiony w pracy [L. 4]. Specyfika i odrębność warunków brzegowych w mikrołożyskach ślizgowych w porównaniu z warunkami brzegowymi aplikowanymi w klasycznym hydrodynamicznym smarowaniu polega na uwzględnieniu wpływu właściwości mechanicznych warstwy wierzchniej na przepływ czynnika smarującego w bardzo cienkiej warstewce filmu o wartościach poniżej jednego mikrometra.
Źródło:: Tribologia; 2010, 3; 231-240
0208-7774
Pojawia się w:: Tribologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: The Dynamic Performance Analysis of the Foil Bearing Struture
Autorzy:: Żywica, G.
Powiązania:: https://bibliotekanauki.pl/articles/386913.pdf
Data publikacji:: 2013
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:: łożysko foliowe
systemy łożyskowania
mikroturbiny
wirnik
foil bearing
bearing systems
micro-turbines
Opis:: Foil bearings are a variety of slide bearings in which an additional set of foils is applied between journal and bush, in order to improve the selected static and dynamic properties. Engineers and researchers from all over the world investigate bearings of this type since many years - both from numerical as well as experimental point of view. Due to the complexity of construction, the reliable simulation models are all the time being searched for. This paper discusses the important stages of elaboration of the structural supporting layer numerical model of the foil bearing as well as results of verification tests. The main goal of the conducted study was assessment of reliability of the elaborated numerical model, in scope of dynamic properties. In the near future it will be used for elaboration of the numerical model of the entire foil bearing, which will take into account also phenomena in fluid-film layer. Those models will be used together to describe bearing system in operation.
Źródło:: Acta Mechanica et Automatica; 2013, 7, 1; 58-62
1898-4088
2300-5319
Pojawia się w:: Acta Mechanica et Automatica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Effect of micro protrusions on the performance of elliptical journal bearings operating with couple stress lubricant
Autorzy:: Abass, Basim Ajeel
Mahdi, Mushrek A.
Powiązania:: https://bibliotekanauki.pl/articles/1840900.pdf
Data publikacji:: 2021
Wydawca:: Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:: elliptical journal bearing
hydrodynamic lubrication
micro-protrusions
couple-stress lubricant
non-Newtonian fluids
smarowanie hydrodynamiczne
płyny nienewtonowskie
Opis:: Elliptical bearing is characterized by low induced temperature and high stability at higher speed in comparison with the cylindrical journal bearing. The performance of such bearings can be affected by the type of oil used and its surface properties. The main goal of this work is to study the surface micro protrusion effect on the steady state operation of elliptical journal bearing lubricated with couple stress lubricant. The modified Reynolds’ equation to take into account the effects of couple stress lubricant and micro protrusions of the bearing surfaces is solved using finite difference method. The governing equations were solved using a prepared FORTRAN computer program. Pressure distribution, load carrying capacity and coefficient of friction have been studied for a bearing in laminar flow regime. The mathematical model was validated by comparing pressure results for the elliptical bearing of the present work with that obtained by Hussain et al.(1996). The obtained results demonstrate that the lubricant pressure and the load carried by the bearing decrease for the bearing with higher ellipticity factor while the load carried by the bearing increases for the bearing with higher protrusions or when using a couple stress fluid with higher couple stress variable.
Źródło:: Diagnostyka; 2021, 22, 2; 97-104
1641-6414
2449-5220
Pojawia się w:: Diagnostyka
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: An attempt at identifying the influence of test head assembly stiffness on the results of a tribological experiment conducted under micro-oscillation conditions
Próba identyfikacji wpływu cech sztywnościowych głowicy badawczej na wynik eksperymentu tribologicznego w warunkach mikrooscylacji
Autorzy:: Gawarkiewicz, R.
Powiązania:: https://bibliotekanauki.pl/articles/188439.pdf
Data publikacji:: 2016
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: dry bearing materials
micro-oscillations
experimental investigations
theoretical analyses
simulation
bezsmarowe materiały łożyskowe
mikrooscylacje
badania doświadczalne
badania teoretyczne
symulacja
Opis:: The outcome of experimental research on a group of dry bearing materials carried out under small oscillation conditions and using a test rig designed and made at Gdansk University of Technology inspired the decision to find out if the stiffness of test head elements influenced the generated results. Therefore, a computer model utilising finite elements was devised and used to simulate the workings of the test head. The model enabled full control of the head’s geometry, and loading and boundary conditions at every stage of simulation. Moreover, the simulation includes the preparation of test head elements, fixings, and the specimen loading, and executes the displacement of the counter-face during full-cycle reciprocating motion. Finally, the results of computer simulation are compared with those produced by experimental testing.
Po badaniach tribologicznych grupy bezsmarowych materiałów łożyskowych w warunkach małych oscylacji, na specjalnie wykonanym w Politechnice Gdańskiej stanowisku badawczym, postanowiono zbadać, czy sztywność elementów głowicy badawczej wpływa na otrzymany wynik eksperymentu. W tym celu przeprowadzono komputerowe symulacje pracy węzła badawczego, wykorzystując metodę elementów skończonych. Model stworzono w taki sposób, aby była możliwa pełna kontrola jego geometrii, obciążenia, warunków brzegowych – i to na każdym etapie symulacji. Badania teoretyczne objęły etapy przygotowania elementów głowicy badawczej do testu, mocowania próbek oraz przeprowadzenie pełnego cyklu ich współpracy z przeciwpróbką w ruchu posuwisto-zwrotnym. Na koniec porównano otrzymane wyniki z wynikami z badań doświadczalnych.
Źródło:: Tribologia; 2016, 268, 4; 79-89
0208-7774
Pojawia się w:: Tribologia
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: Surface Modification Of The High Temperature Porous Sliding Bearings With Solid Lubricant Nanoparticles
Modyfikacja powierzchni porowatych bieżni łożysk do pracy w wysokich temperaturach z zastosowaniem nanocząstek stałego smaru
Autorzy:: Wiśniewska-Weinert, H.
Powiązania:: https://bibliotekanauki.pl/articles/355607.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: bearing sleeve
solid lubricant
powder layers
powder metallurgy
nano- and micro-particles
bieżnia łożyska
smar stały
warstwy proszkowe
metalurgia proszków
nano- i mikrocząstki
Opis:: A surface modification of stainless steel bearing sleeves is developed to improve the tribology characteristics at high temperature. Solid lubricant nano- and microparticles are applied for this purpose. To create the quasi-hydrodynamic lubrication regimes, the solid lubricant powder layer is made by developed pressure impregnation technique. Porous sliding bearing sleeve prototypes were made by powder metallurgy technique. The purpose of the paper is to define the friction and wear characteristics of the sleeves and to determine the influence of sealing of the sliding interface on these characteristics. It is found that application of WS₂ sold lubricant nano- and micro-particles and preservation of a particle leakage out of interface allows to achieve at the high temperature the friction coefficients comparable to those at ambient temperature.
Opracowano modyfikację powierzchni bieżni łożysk wykonanych ze stali nierdzewnej w celu poprawy charakterystyki tribologicznej w podwyższonej temperaturze poprzez zastosowanie stałego czynnika smarnego w postaci nano- i mikro-cząstek. W celu wytworzenia warunków kwasi-hydrodynamicznego smarowania, wytworzono warstwę z proszku smarnego na drodze infiltracji ciśnieniowej. Celem pracy było wyznaczenie charakterystyki ściernej i zużyciowej bieżni oraz określenie wpływu uszczelnienia ślizgających się powierzchni na te charakterystyki. Stwierdzono, że zastosowanie WS₂ jako stałego smaru w postaci nano- i mikro-cząstek oraz zabezpieczenie wypływu z granicy fazowej pozwala uzyskać wartość współczynnika tarcia porównywalną z otrzymywaną dla temperatury otoczenia.
Źródło:: Archives of Metallurgy and Materials; 2015, 60, 3; 2209-2214
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Tytuł:: The analysis of hydrodynamic pressure distribution and load carrying capacity in the gap of slide journal bearings with micro-grooves
Analiza rozkładu ciśnienia hydrodynamicznego oraz siły nośnej w szczelinie poprzecznego łożyska ślizgowego z mikrorowkami
Autorzy:: Miszczak, A.
Powiązania:: https://bibliotekanauki.pl/articles/190378.pdf
Data publikacji:: 2017
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: slide bearing lubrication
journal bearings
hydrodynamic pressure
non-classical surface
micro-grooves
load carrying capacity
friction force
smarowanie łożysk ślizgowych
poprzeczne łożysko ślizgowe
ciśnienie hydrodynamiczne
nieklasyczna powierzchnia
mikrorowki
siła nośna
siła tarcia
Opis:: The purpose of this paper is to analyse the distribution of hydrodynamic pressure, load carrying capacities, and friction force in the gap of the slide bearing on account of the type, number, and size of micro-grooves on the surface of the sleeve. It was assumed that micro-grooves were distributed equally on the circumference of the sleeve as well as parallel to its axis. Micro-bearings with micro-grooves are more and more of ten utilized in the technical applications, e.g., in HDD disks or in computer fans. It is advisable to carry out a numerical analysis on the influence of the number and the size of micro-grooves on the value of the Basic flow parameters in the slide micro-bearing. A laminar flow of lubricating fluid and an isothermal model of the lubrication of the slide bearing was used for the analysis. A classical Newtonian model was applied as the constitutive equation. A cylindrical slide Bering with the finished length and smooth sleeve, and a full wrap angle was used for the research. The density and thermal conductivity of the oil were considered to be constant in the thin film of oil. The results of measurements of shape and sizes of micro-grooves in real micro-slide bearings were presented by the author in the previous publications. The results of that research are used at present to determine the preliminary assumptions concerning the shape and the size of the micro-grooves. The results obtained in the research show the minor influence of micro-grooves on the value of the friction force and a few percentages rate influence of micro-grooves on the value of load carrying capacity.
Celem niniejszej pracy jest analiza rozkładu ciśnienia hydrodynamicznego, siły nośnej i siły tarcia w szczelinie poprzecznego łożyska ślizgowego ze względu na rodzaj, liczby i wielkość mikrorowków na powierzchni panewki. Do analizy przyjęto mikrorowki rozłożone równo po obwodzie panewki i równoległe do osi panewki. Mikrołożyska ślizgowe z mikrorowkami są coraz częściej stosowane w technice, np. w dyskach HDD czy też wentylatorach komputerowych. Celowym jest dokonanie analizy numerycznej, jaki wpływ na wartość podstawowych parametrów przepływowych ma liczba i wielkość mikrorowków. Do analizy hydrodynamicznego smarowania przyjęto laminarny przepływ cieczy smarującej oraz izotermiczny model smarowania łożyska ślizgowego. Jako równanie konstytutywne zastosowano klasyczny model newtonowski. Do rozważań przyjęto walcowe łożysko ślizgowe o skończonej długości z gładką panewką o pełnym kącie opasania. W cienkiej warstwie filmu olejowego przyjęto niezmienność gęstości i współczynnika przewodzenia ciepła oleju. Wyniki pomiaru kształtu i wymiaru mikrorowków w rzeczywistych mikrołożyskach ślizgowych autor przedstawiał we wcześniejszych publikacjach. Wyniki tych badań służą obecnie do określenia wstępnych założeń dotyczących kształtu i wielkości mikrorowków. Uzyskane wyniki badań wskazują na znikomy wpływ mikrorowków na wartość siły tarcia i kilkuprocentowy wpływ mikrorowków na wartość siły nośnej.
Źródło:: Tribologia; 2017, 272, 2; 119-126
0208-7774
Pojawia się w:: Tribologia
Dostawca treści:: Biblioteka Nauki

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