Study of Wear Resistance of Joint Bearings Made of Glass-Epoxy Composite Material

The aim of the work is to evaluate the influence of various antifriction additives on the tribological characteristics of spherical plain bearings made of glass-epoxy composite material under conditions close to operational ones. Tribological tests were conducted on an tribometer IMASH-JOINT plain bearing machine using a shaft-sleeve configuration with reciprocating rotation at a rotation angle of 52° and a frequency of up to 0.5 Hz in air and water environments at specific pressures of 2.7—8.3 MPa. Test results showed that adding PTFE in the form of ground Fluoroplast-4 powder to the glass composite (30 g of the mixture) has a beneficial effect on the friction coefficient of the spherical plain bearing when operating in air in a load range of 2.7—8.3 MPa and an oscillation frequency of 0.25 Hz. Using Fluoroplast-4 powder additive according to GOST 10007–72 leads to a decrease in the friction coefficient and increased wear resistance during longterm tests in water. The friction coefficient of this material when tested in water at p = 8.3 MPa does not exceed 0.24 after 4 hours of operation. The minimum wear rate of the hinge joint in water was observed for the sample of Fluoroplast-4 powder additive according to GOST 10007–72 and amounted to 3.34×10^–6 mm per cycle. The study revealed the effect of PTFE and graphite additives in the studied volumes on the friction coefficient kinetics of a plain bearing during long-term testing. The obtained results allow us to recommend an optimal formulation for the manufacture of bearings made of glass-epoxy composite material for use in hydraulic turbine units.

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