| Popis: |
The results of research on lubricants which are magnetic fluids are presented. The positive effect on the characteristics of the lubricant of pondemotor force that occurs when an external magnetic field is applied is noted. The purpose of this work is to study the properties of magnetic lubricants based on polyethylsiloxane liquids and confirm the previously stated theoretical assumptions. The main objectives of the research are to develop the composition of a lubricant based on a polyethylsiloxane magnetic fluid, to determine the characteristics of adhesion of this material to a metal base, to obtain an adequate mathematical model describing the characteristics of adhesion of the lubricant to the surface, and to determine its stability during operation. Experimental installations and methods for determining the characteristics of the coupling of magnetic fluids with the friction surface, as well as the stability of magnetic fluid itself during operation, have been developed. The prospects of introducing oleic acid into the organosilicon base of the magnetic liquid are noted. A decrease in the adhesion coefficient with an increase in the rotational speed of the samples at loads from 160 N to 320 N was revealed by an average of 1.6...2.7 times. It is proved that the magnetic lubricant adheres to the metal base more strongly than Litol-24 by an average of 6 times, which prevents the rolling elements from slipping during the operation of the samples. Different patterns of changes in adhesion to metal surfaces of Litol-24 and magnetic fluids are noted. An increase in the adhesion coefficient of magnetic fluids under the conditions of applying a constant magnetic field at loads on samples from 480 N to 800 N due to the magnetorheological effect by 20...30% is established. A mathematical model is obtained that adequately describes the change in the adhesion coefficient of the obtained magnetic lubricant. The composition of the magnetic liquid is recommended, consisting of a polyethylene siloxane carrier liquid, a surfactant-oleic acid, and a ferromagnetic phase-magnetite with a particle size of 7.5 nm. High stability of the developed magnetic fluids during longterm operation has been experimentally established. The stability coefficient of the magnetic fluid decreased by 2.51 times in 366 hours. |
