Preparation and Performance of Gel-Impregnated Bearing Self-Lubricating Material

A new self-lubricating bearing material was prepared by pouring the self-constraint gel lubricant into the porous iron-based and poly-based porous bearing material. The supramolecular gelators described herein are completely dissolved in mineral oil or synthetic oil and self-assemble to form the stable gel. The gel has excellent thixotropic properties, unique physical and chemical properties and lubricating properties. So, the gel lubricant can replace the traditional lubricating oil or grease and be poured into a variety of porous iron-based and poly-based bearing materials by phase transformation of gel to obtain the self-lubricating bearing materials.

These porous bearing materials impregnated with gel can greatly enhance their oil storage capacity by improving their viscosity of the base oil in a liquid state. The centrifugation experiments of the oil-impregnated and gel-impregnated bearing materials were accomplished with the speed test from 1 000 to 7 000 stepped by 1 000 r/min intervals with 15 min test. The centrifuged mass loss of porous polyimide bearing materials impregnated with different lubricant at every speed increased in the order: 500SN > 2% A, PAO > 3% B, Oil > 2% C. Meanwhile, the similar results that the centrifuged mass loss of porous iron-based bearing materials impregnated with oil was far bigger than that of porous polyimide bearing materials impregnated with gel at every speed. The results showed that the new self-lubricating bearing material impregnated with gel can reduce the problems of oil rejection and leakage of oil-impregnated bearings under high-speed operation, and improved the oil storage performance of bearings.

Moreover, these bearing materials had a better lubricating capacity than bearing materials impregnated with base oil. Taken PAO and 3% B as an example, the average friction coefficient of three kinds of porous poly-based bearing self-lubricating materials at 2, 4, 6 and 8 N decreased in the following sequence: oil-free > oil-impregnated > gel-impregnated, and the gel-impregnated porous poly-based bearing materials always had a very small and stable friction coefficient during each load. And the results of gel-impregnated porous iron-based bearing materials at the different load were similar to those of gel-impregnated porous poly-based bearing materials. These friction results indicated that gel-impregnated porous poly-based and iron-based bearing had good lubricating properties and friction reduction performance. It was likely that the gel oozing out of the porous bearing may form an effective boundary protective film via adsorption of supramolecular gelator and tribo-chemistry film under the strong shearing, tribo-heat and high contact pressure. At the end of the friction, the liquid returned to the hole of bearing material, and can be stored in the hole of bearing material by condensing again to gel, effectively reduced the loss of base oil. So, these bearing materials impregnated with gel can achieve self-lubrication and improve their oil storage capacity. It was possible to be applied in oil-containing cages/bearing in industry.