Projekt niekonwencjonalnego smarowania mikrołożysk ślizgowych

• Autorzy: Wierzcholski K. , Miszczak A.

Warianty tytułu

EN

The project of non conventional slide micro-bearing lubrication

• Języki publikacji: PL

Abstrakty

PL

Hydrodynamiczna teoria smarowania w zakresie mikrołożysk ślizgowych, a nawet tocznych jest jedną z najszybciej rozwijających się dziedzin tribologii stosowanej. Według aktualnej informacji autorów bardzo mało jest takich badań naukowych prowadzonych w Polsce natomiast na świecie hydrodynamiczna teoria smarowania dla mikro- oraz nanołożysk rozwija się bardzo szybko ze względu na liczne ich zastosowania, między innymi w dyskach komputerowych HDD, mikroturbinach oraz mikrorobotach, a także mikrosilnikach. W niniejszym projekcie autorzy proponują wyznaczać: prędkości przepływów cieczy o własnościach nienewtonowskich w supercienkich warstwach granicznych w skali mikro i nano, ciśnienia hydrodynamiczne i naprężenia, mikro- lub nanosiły tarcia, współczynniki tarcia. Badania uwzględniają zmiany lepkości cieczy w zależności od współczynników materiałowych warstwy wierzchniej panewki.

EN

Hydrodynamic theory of the lubrication of slide micro-bearings is one of the most quickly developing applied tribological domains. In the authors’ opinion, at present, scientific research performed in Poland lacks in the field of micro-nano-tribology; but in the world, such investigations have been very quickly developed and applied in hard computer disks micro-bearings, micro-motors, micro-turbines, and micro-robots. In slide micro-bearings, the lubricant flows in very thin (smaller than 1 micrometer) boundary layers around the rotating journals about 20 000 rpm. The lubricant in such thin layers attains other properties in comparison with lubricant properties flowing in thin boundary layers occurring in classical bearings. The presented research contains the following: the determination of non-Newtonian fluid velocities at the micro- and nano-level occurring in very thin boundary layers flowing inside the microbearing gap, hydrodynamic pressure and stress calculations, the determination of micro- and nano-friction forces to obtain proper friction coefficients in HDD micro-bearings. The existing shear rates during the flow have an influence on the apparent viscosity in the thin layer between the journal and micro-bearing sleeve. In the ultra thin boundary layer, the viscosity additionally changes in the gap height direction. The authors have taken into account the newest theoretical models in the field of micro- and nano-mechanics for the fluid flow in ultra thin boundary layer around the co-operating surfaces in microbearings, and experience gained during the solutions of human biobearings lubrication problems. Up until now, such research has not been performed. For the solving the HDD problems of micro-bearing lubrication, it is very important to perform the measurements of values of material coefficients, i.e. fluid pseudo-viscosity, describing the physical relations between stresses and shear rate tensor coefficients for non-Newtonian lubricants. Such measurements are possible only by using the AFM microscope and new mathematical programs. Moreover, the measurements of micro-bearing surface roughness and friction forces at the nano level during the lubrication are possible only by using the atomic force microscope. Many damages of HDD micro-bearings are connected mainly with the decreasing of the fluid dynamic viscosity. Hence, the presented research has practical meaning, because the lack of knowledge in the field of tribological parameters of HDD micro-bearing operation leads to improper exploitation, and thus to the mechanical reconstruction of the whole HDD micro-bearing spindle system.

Słowa kluczowe

PL

mikrołożyska; mikroszczelina; mikroskop sił atomowych (AFM); wzrost pamięci nośności

EN

micro-bearings; microgap; atomic force microscope; memory capacity increases

• Wydawca: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
• Czasopismo: Tribologia
• Rocznik: 2008
• Tom: nr 4
• Strony: 283--290
• Opis fizyczny: Bibliogr. 16 poz., rys.

Twórcy

autor

Wierzcholski K.

autor

Miszczak A.

• Akademia Morska w Gdyni, ul. Morska 83, 81-225 Gdynia

Bibliografia

• 1. Asada T., Saito H., Asaida Y., Itoh K.: Design of hydrodynamic bearing for high-speed HDD. Microsystem Technologies, Springer Verlag, 2002, 8, pp. 220-226.
• 2. Bekir Sadik Unlu, Denver Atik: Determination of friction coefficient in journal bearing. Material & Design, 2007, 28, pp. 973-977.
• 3. Bharat Bhushan: A Handbookof Nanotribology. Springer Verlag, Berlin-Heidelberg 2004.
• 4. Bharat Bhushan: Micro/nanotribology and its applications to magnetic storage devices and MEMS. Tribology International, 1995, 28, No.2, pp. 85-96.
• 5. Horvath I., Panayotatos P., Yicheng Lu.: A Si MEMS microbearing with integrated safety sensors for surgical applications. Microelectronic Journal, 2001, 32, pp. 1-9.
• 6. Jang G.H., Seo C.H., Ho Seong Lee: Finie element modal analysis of an HDD considering the flexibility of spinning disk- spindle , head - suspension - actuator and supporting structure. Microst. Technol., (Technical Paper), 2007, 13, pp. 837-847.
• 7. Jang G.H., Han J.H., Seo C.H.: Finite element modal analysis of a rotating disk-spindle system in HDD with hydrodynamic bearing considering the flexibility of a complicated supporting structure. Microsyst. Technol., (Technical Paper), 2005, 11, pp. 488-498.
• 8. Jang G.H., Lee S.H., Kim H.W, Kim C.S.: Dynamic analysis of a HDD spindle system with FDBs due to the bearing width and asymmetric grooves of journal bearing. Microsyst. Technol., (Technical Paper), 2005, 11, pp. 499-505.
• 9. Jang G.H., Kim D.K., Han J.H., Kim C.S.: Analysis of dynamic characteristics of a HDD spindle system supported by ball bearing due to temperature variation. Microsystem Technologies, Springer Verlag, 2003, 9, pp. 243-249.
• 10. Jang G.H., Kim D.K., Kim C.S., Lee S.H.: Improvement of dynamic characteristics of a HDD spindle system supported by ball bearing at elevated temperature. Microsyst. Technol., (Technical Paper), 2005, 11, pp. 758-765.
• 11. Jang G.H., Yoon J.W.: Dynamic characteristics of a coupled journal and thrust hydrodynamic bearing in a HDD spindle system due to its groove location. Microsystem Technologies, Springer Verlag, 2002, 8, pp. 261-270.
• 12. Jang G.H., Park S.J., Kim C.S., Han J.H.: Investigation of the electromechanical variables of the spindle motor and the actuator of a HDD due to positioning and free fall. Microsyst. Technol., (Technical Paper), 2007, 13, pp. 797-809.
• 13. Kim D., Lee S., Jin Y., Desta Y., Bryant M.D., Goettert J.: Micro gas bearings fabricated by X-ray lithography. Microsystem Technologies, Springer Verlag, 2004, 10, pp. 456-461.
• 14. Shan X.C, Zhang Q.D., Sun Y.F., Maeda R.: Studies on a micro turbine device with both journal -and thrust-air bearings. Microsyst. Technol., (Technical Paper), 2007, 13, pp. 1501-1508.
• 15. Stephens L.S., Siripuram R., Hayden M., McCart B.: Deterministic Micro Asperities on Bearings and Seals Using a Modified. LIGA Process, 2007, 13, pp. 1501-1508.
• 16. Teo C.J., Spakovszky Z.S.: Analysis of Tilting Effects and Geometric Non-uniformities in Micro-hydrostatic Gas Thrust Bearings. Transaction of the ASME, 2006, Vol. 128, pp. 606.