Background: Spherical contacting surfaces are often designed to increase the contact surface
area and bearing ability, and frequently suffer fluctuating loading, which will play an important
role in tribological properties.
Objective: Effects of high-frequency fluctuating loading on friction and wear performance of spherical-
surface contact sliding pairs should be experimentally investigated.
Methods: Bench tests with the differential gear contacting pairs of heave trucks were conducted under
fluctuating loading generated by the traction force of spring-connecting hanging weights.
Results: High amplitude of fluctuating loads tends to result in different wear forms such as fatigue
wear, plowing damages, material side flow and plastic deformation. The amplitude of the fluctuating
loads has significant influence on the tribological performance of the spherical-surface contact sliding
pairs and is apt to break the frictional stability of the friction pairs indicated by the variation of the
signal components of friction force signals decomposed by discrete wavelet transform method.
Conclusion: The high frequency and large amplitude are the main factors of fluctuating loading that
plays very important role in the tribological characteristics of spherical-surface contact sliding pairs.