Film thickness in miniature ball bearing grease lubricated
| Autor: | D Cojocaru, G Ianuş, V Cârlescu |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | IOP Conference Series: Materials Science and Engineering. 1262:012005 |
| ISSN: | 1757-899X 1757-8981 |
| DOI: | 10.1088/1757-899x/1262/1/012005 |
| Popis: | In this paper the authors theoretically evaluated the film thickness in a miniature angular contact ball bearing in grease and oil lubricated conditions and correlated with the variation of the electrical resistance experimentally determined by using tribometer CETR UMT-2. For grease the authors determined the film thickness considering base oil viscosity. The rotational speed of the inner race varied between 1 and 500 rpm and the axial load applied on a 7000C angular contact ball bearing was 8.1 N. The IVR and EHD lubrication regimes were analytically evaluated depending on the rotational speed and lubricants for both inner and outer race. Based of the dependence between film thickness and electrical resistance obtained for oil was evaluated the real film thickness obtained by using the grease. In case of oil lubricated condition, the experimental results showed an increase of electrical resistance with the rotational speed caused by increasing of the film thickness according to the theoretical model. For grease lubricated condition, ”a V-shaped pattern” was obtained. High values of electrical resistance at very low rotational speeds were observed. By increasing the rotational speed the electrical resistance for grease decreases until a limit speed and increase continuum over this limit. This behaviour was also reported in literature by ball-disc interferometry that showed at very low speeds that the thickener is dominant and over a speed limit the base oil is dominant in generating the film thickness. |
| Databáze: | OpenAIRE |
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